A couple of lectures


September 29, 2013 Posted by | Lectures, Physics | Leave a comment

Dinosaurs past and present (2)

You can read my first post about the book here. I ended up giving it three stars on goodreads. I’m closer to two stars than four. It’s an old book, and although this ads to the reading experience at some points (see also some of the quotes below) it subtracts elsewhere. I wouldn’t recommend it, but it was okay and at times somewhat interesting. Some quotes from the last half of the book:

“Failure to recognize the full potential of trackways and track sites has frequently been a contributing factor in the proliferation of incorrect reconstructions of dinosaur activity. Even where good trackway evidence existed and was well known the interpretation rarely was adequate. For example, the Texan track sites reviewed here tell us that sauropods did not drag their tails, yet probably ninety-nine percent of all sauropod reconstructions made in the last fifty years have suggested that they did.”

“The widely debated issue of dinosaur endothermy and ectothermy has a direct bearing on the question of whether smaller dinosaurs like dromacosaurids or hypsilophodontids should be shown with an outer insulating fur or featherlike pelt. To date no direct evidence exists that any known dinosaur had such a covering…” (As many of you would probably know, we do have such evidence today. See e.g. this and this.)

“Until recently most restored dinosaurs were either drab gray, drab brown, or drab green. The assumption was that since the actual colors were unknown, these were “safe” colors. […] At present there is no proof for pattern or colors in dinosaurs. Considering the likelihood that their lives were governed by the same behavioral principles as modern vertebrates, it seems probable that most of these animals may have had patterns and colors of almost any kind rather than being drab and patternless. […] most baby dinosaurs would almost certainly have needed cryptic markings to help them hide from predators.”

“[A] fascinating possibility would be to re-create as a computer-animated simulation an event like the Glen Rose Sauropod Migration or Lark Quarry Dinosaur Stampede from Australia described by Thulborn and Wade (1979). To do so a map of the trackway assemblage would be recorded on a data tablet and programmed as a perspective view on a computer screen. Since the size, depth, and angle of the tracks can often furnish information about the size, weight, and approximate speed of an animal, the data from a single indivdual’s footprints, if these could be isolated, could be used to construct and program dinosaur images that would fit the size of each set of tracks. Combined with texture mapping and shading techniques, these images could be animated to show the sauropod herd migrating from a moving “camera-eye” vantage point in a simulated Jurassic landscape.” (…just 6 years later people could watch Jurassic Park in movie theatres around the world – I know this was not what the author had in mind, but…)

“During the Mesozoic era herbaceous plants were less abundant than they are now. Larger plants produce less new growth in proportion to their weight than do herbs. Plant biomass must therefore have been more highly visible in dinosaurian landscapes and imparted much “character” to ancient terrestrial ecosystems. Complete plants are seldom found in the fossil record, and whole-plant restorations are rarely made. It is thus very difficult to estimate the appearance of ancient plantscapes.”

“Relative to six other international groups (Hoffman and Nitecki 1985), vertebrate paleontologists are the least supportive of the asteroid-impact hypothesis and the most confident that there was not a Cretaceous mass extinction. In a survey taken during the annual Society of Vertebrate Paleontology meetings in the fall of 1985 (Browne 1985), twenty-seven percent of the respondents saw no evidence for a mass extinction at the end of the Cretaceous and forty-three percent believed that the approximately coincidental impact of an asteroid did not cause the extinctions. […] The point of view I hold cannot have been popular, for only four percent of the respondents at the 1985 meeting (I was unable to attend) felt that an asteroid impact resulted in the extinction of the dinosaurs.”

In case some of you have a desire to read a little more about ‘this kind of stuff’, I’ve posted a few links below:

Petrified Forest National Park (featured wikipedia article).

September 29, 2013 Posted by | Biology, Books, Botany, Paleontology, Zoology | Leave a comment

Dumb Witness

I have given the book four stars on goodreads (average rating: 3.73), even though I’m still considering whether to add a fifth. I got a lot of the details right and I made a lot of correct inferences, but I still didn’t get it completely right in the end (some might argue that I got it very wrong, but I wouldn’t go quite that far) – it’s a really clever setup. The ‘key detail’ so to speak I did not figure out. I thoroughly enjoyed this book.

Books like this one derive most of their success from being brilliant crime stories with intelligent plots, rather than from being highly quotable. So I’ll not quote from the book here. But I think I should add a comment on a related matter. I’ve justified reading fiction over the last few years in part by arguing that doing so on a regular basis would improve my reading speed and my vocabulary. I’m sure you could find worse arguments for reading fiction books. But at least as for the latter part, I’m not sure it’s actually a particularly efficient process.

In my experience most people seem to stop working systematically towards improving their vocabularies once they’ve left the educational system – arguably in some cases they stop far sooner than that. I haven’t really done much over the last years to systematically learn new words – this is not to say that I have not encountered a lot of new concepts and so on while reading a book or an article about a new topic, or while watching a lecture or something like that, the point is just that this process has been somewhat haphazard; new words and concepts have sort of come along for the ride every now and then, but I have done much less to invite them inside than I might have done. Interestingly, this is not even something I’ve given much thought. And so my vocabulary is really quite deficient. I plan to change that, and I think the site, to which I’ve linked before, might be a good tool for that purpose. I’ve created an account on the site and so far it looks like a useful tool. 10 minutes of focused language improvement activities per day would be 60 hours per year. This is more than just a few extra words.

September 28, 2013 Posted by | Books | 2 Comments

Self-pity and self-esteem…

i. “Pity has been defined as “sympathetic heartfelt sorrow for one that is suffering physically or mentally or that is otherwis e distressed or unhappy” (Webster’s Third New International Dictionary, 1961, p. 1726). Self-pity is pity directed toward the self. Consequently, self-pity may be defined as a sympathetic, heartfelt sorrow for oneself prompted by one’s own physical or mental suffering, distress, or unhappiness. Interviews with individuals suffering from chronic illness (Charmaz, 1980) have indicated that self-pity is often accompanied by feelings of sadness and loss and a heightened sense of injustice. Moreover, for a person who feels self-pity, it is characteristic to feel envy of others who have not suffered a similar loss or fate. This is expressed in questions like “Why not them?”, “Why me?”, or “What did I do to de serve this?”, which typically accompany the internal monologue associated with experiences of self-pity (Charmaz, 1980; Grunert, 1988). The experience of self-pity is not restricted to individuals suffering from chronic illness or severe losses. Rather, it is an emotional experience which, in all likelihood, all humans encounter occasionally (Kahn, 1965). Life holds many opportunities to feel sorry for oneself. […]

Self-pitying persons are characterized as likely to overindulge in their failures, hardships, and losses, and the circumstances elicited by these setbacks, thus becoming self-consciously preoccupied with their own suffering (Charmaz, 1980). Nevertheless, self-pity is not an emotional response directed exclusively towards the self. Whereas the primary focus in self-pity may be on the self , self-pity also has a strong interpersonal component. Quite often, self-pity is an emotional response directed towards others with the goal of attracting attention, empathy, or help (Kahn, 1965). In this respect, however, it is a strategy doomed to fail. Whereas initially the display of self-pity may evoke empathy from others (Milrod, 1972), pervasive self-pity will not. On the contrary, people who show pervasive self-pity are most likely to be rejected. Even for individuals who suffer from chronic illness, the period of time is quite limited during which the social environment will allow for a display of self-pity. After a while, people are expected to accept their fate, stop complaining, and carry on with their lives (Charmaz, 1980).”

“the psychiatric and psychoanalytic literature holds that self-pity is linked to feelings of both loneliness and anger. Clinical observations suggest that individuals who experience self-pity usually expect more from the environment than the environment is willing to give (Kahn, 1965). Personal relationships are perceived as unstable and characterized by high demandingness on the part of the person who experiences self-pity, and who sees his or her environment as unwilling to provide the empathy, comfort, and support he or she demands. Consequently, a person who feels self-pity is permanently frustrated. This permanent frustration with others may have two consequences. First, it may lead to social withdrawal and feelings of loneliness (Charmaz, 1980; Kahn, 1965). Second, it may lead to feelings of aggression, hostility, and anger (Kahn, 1965; Milrod, 1972; Wilson, 1985). However, open displays of aggression, hostility, and anger are in conflict with the aims of attracting empathy, support, and acknowledgment from others. […] individuals with a susceptibility for self-pity often are characterized by great self-insecurity. Thus, they may lack the self-assertiveness needed to confront others openly. As a consequence, the direct expression of aggression and hostility will be inhibited. Only mild forms of anger will be expressed, whereas strong anger will be suppressed, turned inward, or even turned against oneself (Milrod, 1991; Wilson, 1985). Under the surface, however, the anger against others will continue to exist, often accompanied by ruminations about retributions for the past (Charmaz, 1980). […] self-pity clearly falls into the class of ineffective coping strategies that are more likely to exaggerate a problem and create new difficulties than to help deal successfully with stressful situations. […] the present findings confirm observations reported in the clinical literature that self-pity is related to loneliness. However, as the two-dimensional conceptualization following Weiss’s (1973) typology of loneliness showed, self-pity was related only to emotional loneliness, but not to social loneliness. […] in line with the clinical literature and previous findings, the present findings show that self-pity is closely related to depression, even when common variance with gender and other facets of neuroticism are controlled for.”

Above quotes are from: Self-Pity: Exploring the Links to Personality, Control Beliefs, and Anger, by Joachim Stöber.

ii. Rumination mediates the prospective effect of low self-esteem on depression: a five-wave longitudinal study.

“Previous research supports the vulnerability model of low self-esteem and depression, which states that low self-esteem operates as a prospective risk factor for depression. However, it is unclear which processes mediate the effect of low self-esteem. To test for the mediating effect of rumination, the authors used longitudinal mediation models, which included exclusively prospective effects and controlled for autoregressive effects of the constructs. Data came from 663 individuals (aged 16 to 62 years), who were assessed 5 times over an 8-month period. The results indicated that low self-esteem predicted subsequent rumination, which in turn predicted subsequent depression, and that rumination partially mediated the prospective effect of low self-esteem on depression. These findings held for both men and women, and for both affective-cognitive and somatic symptoms of depression.” […]

“A growing body of research suggests that low self-esteem is a risk factor for the development of depression (e.g., Kernis et al., 1998; Orth, Robins, & Roberts, 2008; Orth, Robins, Trzesniewski, Maes, & Schmitt, 2009; Roberts & Monroe, 1992; Sowislo & Orth, 2011). In these studies, which used longitudinal designs and controlled for prior levels of the constructs, low self-esteem — which is defined as “a person’s appraisal of his or her value” (Leary & Baumeister, 2000, p. 2) — prospectively predicted changes in the level of depression. Overall, the evidence supports the vulnerability model, which states that low self-esteem is a diathesis exerting causal influence in the onset and maintenance of depression (e.g., Beck, 1967; Metalsky, Joiner, Hardin, & Abramson, 1993). […] An alternative model of the relation between low self-esteem and depression is the scar model, which states that low self-esteem is an outcome rather than a cause of depression, because episodes of depression may leave permanent scars in the self-concept of the individual (cf. Coyne, Gallo, Klinkman, & Calarco, 1998; Rohde, Lewinsohn, & Seeley, 1990; Shahar & Davidson, 2003; for an overview of the scar and vulnerability model, see Zeigler-Hill, 2011). It is important to note that the vulnerability model and the scar model are not mutually exclusive because both processes (i.e., low self-esteem contributing to depression and depression eroding self-esteem) might operate simultaneously. Yet, the extant literature speaks against the scar model (cf. Ormel, Oldehinkel, & Vollebergh, 2004; Orth et al., 2008; Orth, Robins, & Meier, 2009; Orth, Robins, Trzesniewski, et al., 2009; Sowislo & Orth, 2011; but see Shahar & Davidson, 2003).”

iii. “our review showed that high self-esteem is closely associated with self-enhancement, a bias that has both beneficial and detrimental consequences. Jean Twenge, Keith Campbell, and their colleagues have recently found that narcissism, the dark side of high self-esteem, has risen dramatically over the last 25 years (Associated Press, 2007)

The motive of self-enhancement and the dependency of self-esteem on the approval of others who are also motivated to self-enhance virtually ensure that not everyone will get the esteem they desire. Research inspired by sociometer theory has shown that self-esteem is closely attuned to social acceptance (Leary, 2004). Consider a pair of individuals, each of whom has a choice between approving of the other and withholding approval. The self-enhancement motive implies a preference ranking that constitutes a Prisoner’s Dilemma. […] Matters improve inasmuch as people find a way to coordinate their behaviors by projecting their own choices strategically onto one another or by playing the approval game repeatedly (Krueger, 2007). Still, it is unrealistic to expect perfect coordination where everyone pats everyone else on the back. Members of human groups are notorious for negotiating status, power, and prestige, often by creatively deceitful means. In a provocative urban ethnography, Anderson (1994) found self-esteem to be a scarce and contested resource, which individuals could gain at the expense of others. The goal of raising self-esteem across the board is seductive because it is not a zero-sum game. Yet because individuals are, in part, the source of the self-esteem of others, not everyone can attain the highest score.”

From Is the Allure of Self-Esteem a Mirage After All?, a brief note by Krueger, Vohs and Baumeister.

iv. Self-Esteem Development From Age 14 to 30 Years: A Longitudinal Study, by Erol and Orth.

“We examined the development of self-esteem in adolescence and young adulthood. Data came from the Young Adults section of the National Longitudinal Survey of Youth, which includes 8 assessments across a 14-year period of a national probability sample of 7,100 individuals age 14 to 30 years. Latent growth curve analyses indicated that self-esteem increases during adolescence and continues to increase more slowly in young adulthood. Women and men did not differ in their self-esteem trajectories. […] At each age, emotionally stable, extraverted, and conscientious individuals experienced higher self-esteem than emotionally unstable, introverted, and less conscientious individuals. Moreover, at each age, high sense of mastery, low risk taking, and better health predicted higher self-esteem. Finally, the results suggest that normative increase in sense of mastery accounts for a large proportion of the normative increase in self-esteem.”

“Low self-esteem in adolescence and young adulthood is a risk factor for negative outcomes in important life domains. For example, Trzesniewski et al. (2006) found that low self-esteem during adolescence predicts poorer mental and physical health, worse economic well-being, and higher levels of criminal activity in young adulthood. Similarly, other studies found that low self-esteem prospectively predicts antisocial behavior, eating disturbances, depression, and suicidal ideation (Donnellan, Trzesniewski, Robins, Moffitt, & Caspi, 2005; McGee & Williams, 2000; Orth, Robins, & Roberts, 2008).”

v. Identity Status and Self-Esteem: A Meta-Analysis, by Ryeng, Kroger and Martinussen. Unfortunately I’ve not been able to find an ungated version to which I can link, but here’s part of the abstract:

“This study examines the relationship between Marcia’s identity statuses and self-esteem measures through techniques of meta-analysis. Global self-esteem, as used here, refers to one’s positive or negative attitudes toward oneself, degree of self-respect, self-worth, and faith in one’s own capacities. Identity theory would predict strong linkages between the development of self-esteem and identity; however, previous research findings have been inconsistent regarding the nature of this relationship. Two conflicting explanatory models are examined here: (a) high self-esteem is linked with “high” identity status (achievement and moratorium) and low self-esteem with “low” identity status (foreclosure and diffusion); and (b) high self-esteem is linked with identity commitment and low self-esteem with lack of identity commitment. […] Results do not provide clear support for either explanatory model, although support exists from categorical measures of identity status that high self-esteem is linked with the committed identity statuses.”

vi. Does low self-esteem predict depression and anxiety? A meta-analysis of longitudinal studies, by Sowislo and Orth.

“Low self-esteem and depression are strongly related, but there is not yet consistent evidence on the nature of the relation. Whereas the vulnerability model states that low self-esteem contributes to depression, the scar model states that depression erodes self-esteem. Furthermore, it is unknown whether the models are specific for depression or whether they are also valid for anxiety. We evaluated the vulnerability and scar models of low self-esteem and depression, and low self-esteem and anxiety, by meta-analyzing the available longitudinal data (covering 77 studies on depression and 18 studies on anxiety). The mean age of the samples ranged from childhood to old age. In the analyses, we used a random-effects model and examined prospective effects between the variables, controlling for prior levels of the predicted variables. For depression, the findings supported the vulnerability model: The effect of self-esteem on depression ( .16) was significantly stronger than the effect of depression on self-esteem ( .08). In contrast, the effects between low self-esteem and anxiety were relatively balanced: Self-esteem predicted anxiety with .10, and anxiety predicted self-esteem with .08. Moderator analyses were conducted for the effect of low self-esteem on depression; these suggested that the effect is not significantly influenced by gender, age, measures of self-esteem and depression, or time lag between assessments. If future research supports the hypothesized causality of the vulnerability effect of low self-esteem on depression, interventions aimed at increasing self-esteem might be useful in reducing the risk of depression.”

vii. Life-Span Development of Self-Esteem and Its Effects on Important Life Outcomes, by Orth, Robins, and Widaman.

“We examined the life-span development of self-esteem and tested whether self-esteem influences the development of important life outcomes, including relationship satisfaction, job satisfaction, occupational status, salary, positive and negative affect, depression, and physical health. Data came from the Longitudinal Study of Generations. Analyses were based on 5 assessments across a 12-year period of a sample of 1,824 individuals ages 16 to 97 years. First, growth curve analyses indicated that self-esteem increases from adolescence to middle adulthood, reaches a peak at about age 50 years, and then decreases in old age. Second, cross-lagged regression analyses indicated that self-esteem is best modeled as a cause rather than a consequence of life outcomes. Third, growth curve analyses, with self-esteem as a time-varying covariate, suggested that self-esteem has medium-sized effects on life-span trajectories of affect and depression, small to medium-sized effects on trajectories of relationship and job satisfaction, a very small effect on the trajectory of health, and no effect on the trajectory of occupational status. These findings replicated across 4 generations of participants—children, parents, grandparents, and their great-grandparents. Together, the results suggest that self-esteem has a significant prospective impact on real-world life experiences and that high and low self-esteem are not mere epiphenomena of success and failure in important life domains.”

A figure from the article (click to view full size):

Self-esteem life trajectory

“Although the present study suggests an earlier peak of the self-esteem trajectory (i.e., at about age 50 years) than in previous research (at about age 60 years; Orth et al., 2010), the overall shape of the trajectory was similar. The repeated finding of a relatively strong decline of self-esteem in old age is of particular importance, given conflicting reviews of the literature […]

Surprisingly, gender did not affect the level or the trajectory of self-esteem; in contrast, previous research has suggested that men tend to report higher self-esteem than women, at least in adolescence and adulthood, although the effect size is generally small (Kling, Hyde, Showers, & Buswell, 1999; Orth et al., 2010; Robins, Trzesniewski, Tracy, Gosling, & Potter, 2002). Moreover, in the present study, no cohort differences in the trajectory of self-esteem were found, replicating findings from Erol and Orth (2011) and Orth et al. (2010). Thus, although the claim that there has been a generational increase in self-esteem levels (i.e., that more recent generations have higher self-esteem than previous generations) has intuitive appeal (Twenge & Campbell, 2001, 2008), the available evidence suggests that the average self-esteem trajectory has not changed across the generations born in the 20th century (Trzesniewski & Donnellan, 2010; Trzesniewski, Donnellan, & Robins, 2008) […]

The present research also addressed the important question of whether self-esteem is better thought of as a cause or a consequence of life outcomes. We tested for reciprocal prospective relations between self-esteem and a set of life outcomes that are central to having a successful and fulfilling life, including measures of well-being (positive affect, negative affect, and depression), enjoying and succeeding in work, having a satisfying romantic relationship, and physical health. With regard to depression, we replicated previous studies showing that low self-esteem prospectively predicts depression but that the effect of depression on low self-esteem is small or nonsignificant (Metalsky et al., 1993; Orth, Robins, & Meier, 2009; Orth, Robins, Trzesniewski, et al., 2009; Roberts & Monroe, 1992). A similar pattern emerged for measures of dispositional positive and negative affect: Self-esteem predicted increases in positive affect and decreases in negative affect, controlling for prior levels in the constructs, but positive affect did not predict subsequent self-esteem, and negative affect had a statistically significant but small negative effect on self-esteem. In addition, we found that self-esteem was prospectively related to higher levels of relationship satisfaction, job satisfaction, occupational status, salary, and physical health, con- trolling for prior levels of these variables, but none of these life outcomes had reciprocal effects on self-esteem (or, if significant, the coefficients were small). Moreover, all results held across generations. Thus, regardless of whether one was born in the early 1900s or in the 1980s, self-esteem had significant benefits for people’s experiences of love, work, and health, supporting hypotheses about the beneficial consequences of high self-esteem (Donnellan, Trzesniewski, Robins, Moffitt, & Caspi, 2005; Swann et al., 2007; Trzesniewski et al., 2006; but see Baumeister et al., 2003).”

September 27, 2013 Posted by | Psychology, Studies | Leave a comment

Dinosaurs past and present (1)

It’s a neat little book.

Some quotes from the first half:

“most trackways of extant mammal species seen in the wild record leisurely paces made during the slow, unhurried daily and seasonal routine […] Top-speed runs are very important in the evolution of limb structure, but maximum speed accounts for only a tiny fraction of the total footsteps taken by an individual animal during its lifetime. Fossil footprints should be viewed as the documentation of an average daily cruising speed, not of top speed.  […] dinosaurs had cruising speeds as high or higher than that of mammals with comparable body size and feeding habits. Mammoths cruised at speeds no higher than that of nodosaurid and sauropod dinosaurs. Moa cruising speed was no higher than that of duck-billed dinosaurs. Theropod dinosaurs cruised at higher speeds than that of modern mammals. Therefore we can conclude that the average everyday pace of dinosaurian locomotor activity was as quick as or quicker than that of the present-day Mammalia.

In addition, the footprint survey showed that the primitive reptiles and amphibians of the Paleozoic cruised at speeds far slower than that of dinosaurs and mammals. Life in the Carboniferous and early Permian must have been played out at a toad’s pace. A sudden and dramatic increase in average cruising speed coincided with the rise of the advanced mammallike reptiles (therapsids) and thecodonts at the beginning of the Triassic. And the Triassic acceleration of cruising speed coincides precisely with change in bone histology, documented by Ricqlès (1974)”

“MacArthur and Wilson (1967) argue that on a continuous scale of reproductive strategies there are two extreme kinds. One is “r selection” (r stands for rate of increase by reproduction) in which an individual has many offspring either by having a few offspring at frequent intervals or by having large numbers of offspring at one time. One characteristic of organisms that exhibit r selection is that they are small. A good example among mammals is mice versus elephants; mice show r selection, elephants do not. A pair of mice will produce many generations in a short time, while a pair of elephants have few young and each generation takes more than ten years. Elephants show “K selection” (K stands for the carrying capacity of the environment, which becomes the limiting factor for these animals). Two features of animals that exhibit K selection are large size and long generation time.
K and r selections are the two extremes of a range of reproductive strategies. K selection is especially suited to stable climates in which the full resources of the environment can be exploited safely. The tropics are a good example. […] In contrast, r selection is best suited to unpredictable environments, such as temperate and subpolar regions where the production of large numbers of offspring insures against environmental catastrophe, freeze, flood, or drought. Clutch sizes correlate inversely with body size (Calder 1983).” [To me this was just review of stuff I already knew, but I figured some of you didn’t know about r/K selection theory, and the tradeoff between quality and quantity of offspring is an important concept one should know about so I decided to include the quote in the post. Some of the stuff below is review as well, but again – it’s important stuff you should know and it doesn’t hurt to go over it again.]

“The larger the animal, the lower the metabolic rate per unit body weight. Although metabolic rate seems to be related to surface area, it is not. (Not all mammals are constantly warm; those that are not will lose heat to the air when the air is cooler than they are and gain heat when the air temperature exceeds their own. Yet, in heterotherms the larger the animal, the lower the metabolic rate and their metabolic rates also correlate with their surface areas.) Coulson (1984) theorizes that metabolic rate is determined principally by the distance blood has to travel from the heart to the capillary, and the greater the distance, the greater the resistance and the slower the flow through the capillaries and veins and return to the heart.”

“Stepping frequency is inversely related to body size or limb length (Calder 1984). Stridelength increases with size (Maloiy et al. 1979). The total energy cost of travel increases with size but is cheaper per kilogram (Bennett 1982, for reptiles; Taylor, Heglund, and Maloiy, 1982, for mammals).”

“For mammals, at least, size is a significant factor in determining a sense of hearing. Mice can hear more than two octaves higher than elephants at an intensity level of sixty decibels. A strong inverse relationship can be recorded between the high-frequency cutoff (at sixty decibels) and the time difference between the arrival of sounds at the two ears in mammals (Heffner and Masterton 1980; Heffner and Heffner 1980). Birds do not seem to exhibit such a relationship with the high-frequency cutoff, but extremely large birds have not been examined (Knudsen 1980; Dooling 1980).”

Volume is proportional to length cubed; surface area is proportional to length squared. If a simple geometric shape such as a cube doubles in length, it will acquire four times the original surface area and eight times the original volume. When we think of tiny dinosaurs, it is helpful to think of the converse of the consequences such scaling where volume is dramatically reduced relative to surface area […] The result is a tiny individual with a high surface to volume ratio. […] this most profoundly affects heat exchange and other exchange phenomena […] Tiny animals are more likely to seek shelter when stressed by temperature change.”

September 26, 2013 Posted by | Biology, Books, Paleontology, Zoology | 3 Comments


i. I’ve played some good chess over the last few weeks. I’m currently participating in an unrated chess tournament –  the format is two games per evening (one with the white pieces and one with the black), with 45 minutes per person per game. The time control means that although the games aren’t rated, they’re at least long enough to be what I’d consider ‘semi-serious’.

Here’s a recent game I played, from that tournament – I was white. It wasn’t without flaws on my part but it was ‘good enough’ as he was basically lost out of the opening. I wasn’t actually sure if 7.Qd4 could be played (this should tell you all you need to know about how much I know about the Pirc…) but I was told after the game that it was playable – my opponent had seen it in a book before, but he’d forgotten how the theory went and so he made a blunder. It was the second game that evening, played shortly after I’d held my opponent, a ca. 2000 FIDE rated player, to a draw in the first game. I mention the first game also because I think it’s quite likely that the outcome of that game played a role in the mistake he made in the second game. The average rating of my opponents so far has been 1908 (I’ve also drawn a 2173 FIDE guy along the way, though the chess in that case was not that great), and I’m at +1 after six games. I’ve beaten FMs before in bullet and blitz, but as mentioned these games are a tad more serious than, say, random 3 minute games online, and this is one of the first times I’ve encountered opponents as strong as this in a ‘semi-serious’ setting. And I’m doing quite well. It probably can’t go on, but I’m enjoying it while it lasts.

ii. An interesting medical lecture about vaccines:

iii. Estimating Gender Disparities in Federal Criminal Cases.

“This paper assesses gender disparities in federal criminal cases. It finds large gender gaps favoring women throughout the sentence length distribution (averaging over 60%), conditional on arrest offense, criminal history, and other pre-charge observables. Female arrestees are also significantly likelier to avoid charges and convictions entirely, and twice as likely to avoid incarceration if convicted. Prior studies have reported much smaller sentence gaps because they have ignored the role of charging, plea-bargaining, and sentencing fact-finding in producing sentences. Most studies control for endogenous severity measures that result from these earlier discretionary processes and use samples that have been winnowed by them. I avoid these problems by using a linked dataset tracing cases from arrest through sentencing. Using decomposition methods, I show that most sentence disparity arises from decisions at the earlier stages, and use the rich data to investigate causal theories for these gender gaps.”

Here’s what she’s trying to figure out: “In short, I ask: do otherwise-similar men and women who are arrested for the same crimes end up with the same punishments, and if not, at what points do their fates diverge?”

Some stuff from the paper:

“The estimated gender disparities are strikingly large, conditional on observables. Most notably, treatment as male is associated with a 63% average increase in sentence length, with substantial unexplained gaps throughout the sentence distribution. These gaps are much larger than those estimated by previous research. This is because, as the sequential decomposition demonstrates, the gender gap in sentences is mostly driven by decisions earlier in the justice process—most importantly sentencing fact-finding, a prosecutor-driven process that other literature has ignored.

But why do these disparities exist? Despite the rich set of covariates, unobservable gender differences are still possible, so I cannot definitively answer the causal question. However, several plausible theories have testable implications, and I take advantage of the unusually rich dataset to explore them. I find substantial support for some theories (particularly accommodation of childcare responsibilities and perceived role differences in group crimes), but that these appear only to partially explain the observed disparities.” […]

“Columns 11-12 of Table 5 show that the gender gap is substantially larger among black than non-black defendants (74% versus 51%). The race-gender interaction adds to our understanding of racial disparity: racial disparities among men significantly favor whites,29 but among women, the race gap in this sample is insignificant (and reversed in sign). The interaction also offers another theory for the gender gap: it might partly reflect a “black male effect”—a special harshness toward black men, who are by far the most incarcerated group in the U.S. […] This theory only goes so far, however — the gender gap even among non-blacks is over 50%, far larger than the race gap among men.”

iv. Low glycaemic index, or low glycaemic load, diets for diabetes mellitus?

“Nutritional factors affect blood glucose levels, however there is currently no universal approach to the optimal dietary strategy for diabetes. Different carbohydrate foods have different effects on blood glucose and can be ranked by the overall effect on the blood glucose levels using the so-called glycaemic index. By contributing a gradual supply of glucose to the bloodstream and hence stimulating lower insulin release, low glycaemic index foods, such as lentils, beans and oats, may contribute to improved glycaemic control, compared to high glycaemic index foods, such as white bread. The so-called glycaemic load represents the overall glycaemic effect of the diet and is calculated by multiplying the glycaemic index by the grammes of carbohydrates.

We identified eleven relevant randomised controlled trials, lasting 1 to 12 months, involving 402 participants. Metabolic control (measured by glycated haemoglobin A1c (HbA1c), a long-term measure of blood glucose levels) decreased by 0.5% HbA1c with low glycaemic index diet, which is both statistically and clinically significant. Hypoglycaemic episodes significantly decreased with low glycaemic index diet compared to high glycaemic index diet. No study reported on mortality, morbidity or costs.”

v. I started reading Dinosaurs Past and Present a few days ago. It’s actually a quite short and neat book, but I haven’t gotten very far as other things have gotten in the way. I just noticed that a recently published PlosOne study deals with some of the same topics covered in the book – I haven’t read it yet but if you’re curious you can read the article on Forearm Posture and Mobility in Quadrupedal Dinosaurs here.

September 25, 2013 Posted by | Chess, Data, Diabetes, Immunology, Lectures, Medicine, Paleontology, Personal, Studies | Leave a comment

Wikipedia articles of interest

It’s been a while since I’ve posted one of these and my collection of ‘articles I’d like to blog at some point’ has accumulated for a while, so I decided to post a few more links than I usually do while also limiting coverage of specific articles a little:

i. Halifax Explosion.

“The Halifax Explosion occurred near Halifax, Nova Scotia, Canada, on the morning of Thursday, December 6, 1917. SS Mont-Blanc, a French cargo ship fully laden with wartime explosives, collided with the Norwegian vessel SS Imo[2] in the Narrows, a strait connecting the upper Halifax Harbour to Bedford Basin. Approximately twenty minutes later, a fire on board the French ship ignited her explosive cargo, causing a cataclysmic explosion that devastated the Richmond District of Halifax. Approximately 2,000 people were killed by debris, fires, and collapsed buildings, and it is estimated that nearly 9,000 others were injured.[3] The blast was the largest man-made explosion prior to the development of nuclear weapons[4] with an equivalent force of roughly 2.9 kilotons of TNT. […]

While the exact number killed by the disaster is unknown, a common estimate is 2,000. The Halifax Explosion Remembrance Book, an official database compiled in 2002 by the Nova Scotia Archives and Records Management identified 1,950 victims.[66] As many as 1,600 people died immediately in the blast, the tsunami, and collapse of buildings. The last body, a caretaker killed at the Exhibition Grounds, was not recovered until the summer of 1919.[67] An additional 9,000 were injured, 6,000 of them seriously; 1,630 homes were destroyed in the explosion and fires, with 12,000 more houses damaged. This disaster left roughly 6,000 people homeless and without shelter and 25,000 without adequate housing. The city’s industrial sector was in large part gone, with many workers among the casualties and the dockyard heavily damaged.

The explosion was responsible for the vast majority of Canada’s World War I-related civilian deaths and injuries, and killed more Nova Scotian residents than were killed in combat. Detailed estimates showed that among those killed, 600 were under the age of 15, 166 were labourers, 134 were soldiers and sailors, 125 were craftsmen, and 39 were workers for the railway.

Many of the wounds inflicted by the blast were permanently debilitating, with many people partially blinded by flying glass or by the flash of the explosion. Thousands of people had stopped to watch the ship burning in the harbour, with many people watching from inside buildings, leaving them directly in the path of flying glass from shattered windows. Roughly 600 people suffered eye injuries, and 38 of those lost their sight permanently.”

ii. Taman Shud Case.

“The Taman Shud Case,[notes 1] also known as the Mystery of the Somerton Man, is an unsolved case of an unidentified man found dead at 6:30 a.m., 1 December 1948, on Somerton beach in Adelaide, South Australia. It is named for a phrase, tamam shud, meaning “ended” or “finished”, on a scrap of the final page of The Rubaiyat, found in the hidden pocket of the man’s trousers.

Considered “one of Australia’s most profound mysteries” at the time,[1] the case has been the subject of intense speculation over the years regarding the identity of the victim, the events leading up to his death, and the cause of death. Public interest in the case remains significant because of a number of factors: the death occurring at a time of heightened tensions during the Cold War, what appeared to be a secret code on a scrap of paper found in his pocket, the use of an undetectable poison, his lack of identification, and the possibility of unrequited love.

iii. Bird strike. These are actually a much bigger deal than I’d imagined:

“A bird strike—sometimes called birdstrike, avian ingestion (only if in an engine), bird hit, or BASH (for Bird Aircraft Strike Hazard)—is a collision between an airborne animal (usually a bird or bat[1]) and a human-made vehicle, especially aircraft. The term is also used for bird deaths resulting from collisions with human-made structures such as power lines, towers and wind turbines (see Bird-skyscraper collisions and Towerkill).[2] A bug strike is an impairment of an aircraft or aviator by an airborne insect.

Bird strikes are a significant threat to flight safety, and have caused a number of accidents with human casualties.[3] The number of major accidents involving civil aircraft is quite low and it has been estimated that there is only about 1 accident resulting in human death in one billion (109) flying hours.[4] The majority of bird strikes (65%) cause little damage to the aircraft;[5] needless to say, the collision is usually fatal to the bird.

Most accidents occur when the bird hits the windscreen or flies into the engines. These cause annual damages that have been estimated at $400 million[3] within the United States of America alone and up to $1.2 billion to commercial aircraft worldwide.[6] […]

Jet engine ingestion is extremely serious due to the rotation speed of the engine fan and engine design. As the bird strikes a fan blade, that blade can be displaced into another blade and so forth, causing a cascading failure. Jet engines are particularly vulnerable during the takeoff phase when the engine is turning at a very high speed and the plane is at a low altitude where birds are more commonly found.

The force of the impact on an aircraft depends on the weight of the animal and the speed difference and direction at the impact. The energy of the impact increases with the square of the speed difference. Hence a low-speed impact of a small bird on a car windshield causes relatively little damage. High speed impacts, as with jet aircraft, can cause considerable damage and even catastrophic failure to the vehicle. The energy of a 5 kg (11 lb) bird moving at a relative velocity of 275 km/h (171 mph) approximately equals the energy of a 100 kg (220 lb) weight dropped from a height of 15 metres (49 ft). […]

The largest numbers of strikes happen during the spring and fall migrations. Bird strikes above 500 feet (150 m) altitude are about 7 times more common at night than during the day during the bird migration season.[17]

Large land-bound animals, such as deer, can also be a problem to aircraft during take off and landing, and over 650 civil aircraft collisions with deer were reported in the U.S. between 1990 and 2004.

An animal hazard reported from London Stansted Airport in England is rabbits: they get run over by ground vehicles and planes, and they pass large amounts of droppings, which attract mice, which attract owls, which become another birdstrike hazard.[18] […]

The energy that must be dissipated in the collision is approximately the relative kinetic energy [Ek] of the bird, defined by the equation  [Ek=1/2*mv2] where [m] is the mass and [v] is the relative velocity (the difference of the velocities of the bird and the plane if they are flying in the same direction and the sum if they are flying towards each other). Therefore the speed of the aircraft is much more important than the size of the bird when it comes to reducing energy transfer in a collision. The same can be said for jet engines: the slower the rotation of the engine, the less energy which will be imparted onto the engine at collision.

The body density of the bird is also a parameter that influences the amount of damage caused.[24]

iv. Tacoma Narrows Bridge (1940).

“The 1940 Tacoma Narrows Bridge was the first Tacoma Narrows Bridge, a suspension bridge in the U.S. state of Washington that spanned the Tacoma Narrows strait of Puget Sound between Tacoma and the Kitsap Peninsula. It opened to traffic on July 1, 1940, and dramatically collapsed into Puget Sound on November 7 of the same year. At the time of its construction (and its destruction), the bridge was the third longest suspension bridge in the world in terms of main span length, behind the Golden Gate Bridge and the George Washington Bridge.

Construction on the bridge began in September 1938. From the time the deck was built, it began to move vertically in windy conditions, which led to construction workers giving the bridge the nickname Galloping Gertie. The motion was observed even when the bridge opened to the public. Several measures aimed at stopping the motion were ineffective, and the bridge’s main span finally collapsed under 40-mile-per-hour (64 km/h) wind conditions the morning of November 7, 1940.”

Don’t miss Barney Elliott’s video footage (roughly in the middle of the article)  of the disaster!

v. Myrtle Corbin.

Josephine Myrtle Corbin (May 12, 1868 in Lincoln County, Tennessee[1] – May 6, 1928 in Cleburne, Texas) was born a dipygus. This referred to the fact that she had two separate pelvises side by side from the waist down, as a result of her body axis splitting as it developed. Each of her smaller inner legs was paired with one of her outer legs. She was said to be able to move her inner legs, but they were too weak for walking.”

Here’s an image from the article:

“At the age of 19 she married Clinton Bicknell, and she would go on to give birth to four daughters and a son.”

vi. Black mamba. (Add to the list of reasons why I’m glad I don’t live in Africa…)

“The black mamba (Dendroaspis polylepis), also called the common black mamba or black-mouthed mamba,[4] is the longest venomous snake in Africa, averaging around 2.5 to 3.2 m (8.2 to 10 ft) in length, and sometimes growing to lengths of 4.45 m (14.6 ft).[5] It is named for the black colour of the inside of the mouth rather than the colour of its scales which varies from dull yellowish-green to a gun-metal grey. It is also the fastest snake in the world, capable of moving at 4.32 to 5.4 metres per second (16–20 km/h, 10–12 mph).[6] The black mamba has a reputation for being very aggressive, but it usually attempts to flee from humans like most snakes, unless it is threatened.[7] Without rapid and vigorous antivenom therapy, a bite from a black mamba is almost always fatal.[7][8][9] […]

Among mambas, toxicity of individual specimens within the same species and subspecies can vary greatly based on several factors, including geographical region (there can be great variation in toxicity from one town or village to another).[30] […] It is estimated that only 10 to 15 mg will kill a human adult, and its bites delivers about 50–120 mg of venom on average.[40][14] The largest envenomation on record is 400 mg.[36] Its bite is often called “the kiss of death” because, before antivenom was widely available, the mortality rate from a bite was 100% since this species always delivers fatal dosage of venom during every envenomation.[7][8][9] Severe black mamba envenomation can kill a person in 30 minutes,[9] but sometimes it takes up to 2–3 hours,[15][9] depending upon many factors.[9] […] Due to antivenom, a bite from a black mamba is no longer a certain death sentence. But in order for the antivenom to be successful, vigorous antivenom therapy must be administered very rapidly post-envenomation.”

Despite how dangerous these animals are, it’s not the snake species that causes the most deaths in Africa. That’s this one.

vii. Wernher von Braun.

Wernher Magnus Maximilian, Freiherr von Braun (March 23, 1912 – June 16, 1977) was a German, and later naturalized, American rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and, subsequently, in the United States. He is credited as being the “Father of Rocket Science”.

In his 20s and early 30s, von Braun was the central figure in Germany’s rocket development program, responsible for the design and realization of the V-2 combat rocket during World War II. After the war, he and some select members of his rocket team were taken to the United States as part of the then-secret Operation Paperclip. Von Braun worked on the United States Army intermediate range ballistic missile (IRBM) program before his group was assimilated by NASA. Under NASA, he served as director of the newly formed Marshall Space Flight Center and as the chief architect of the Saturn V launch vehicle, the superbooster that propelled the Apollo spacecraft to the Moon.[1]

viii. Taiwan under Japanese rule.

“Between 1895 and 1945, Taiwan (including the Pescadores) was a dependency of the Empire of Japan. The expansion into Taiwan was a part of Imperial Japan’s general policy of southward expansion during the late 19th century.[2]

As Taiwan was Japan’s first overseas colony, Japanese intentions were to turn the island into a showpiece “model colony”.[3] As a result, much effort was made to improve the island’s economy, industry, public works and to change its culture.

The relative failures of immediate post–World War II rule by the Kuomintang led to a certain degree of nostalgia amongst the older generation of Taiwanese who experienced both. This has affected, to some degree, issues such as national identity, ethnic identity and the Taiwan independence movement. Partly as a result, the people of Taiwan in general feel much less antipathy towards the legacy of Japanese rule than other countries in Asia.[4] […]

As part of the colonial government’s overall goal of keeping the anti-Japanese movement in check, public education became an important mechanism for facilitating both control and intercultural dialogue. While secondary education institutions were restricted mostly to Japanese nationals, the impact of compulsory primary education on the Taiwanese was immense.

On July 14, 1895, Isawa Shūji was appointed as the first Education Minister, and proposed that the Colonial Government implement a policy of compulsory primary education for children (a policy that had not even been implemented in Japan at the time). The Colonial Government established the first Western-style primary school in Taipei (the modern day Shilin Elementary School) as an experiment. Satisfied with the results, the government ordered the establishment of fourteen language schools in 1896, which were later upgraded to become public schools. During this period, schools were segregated by ethnicity. Kōgakkō (公學校, Public Schools) were established for Taiwanese children, while shōgakkō (小學校, Elementary Schools) were restricted to the children of Japanese nationals. Schools for aborigines were also established in aboriginal areas. Criteria were established for teacher selection, and several teacher training schools such as Taihoku Normal School were founded. Secondary and post-secondary educational institutions, such as Taihoku Imperial University were also established, but access was restricted primarily to Japanese nationals. The emphasis for locals was placed on vocational education, to help increase productivity. […]

By 1944, there were 944 primary schools in Taiwan with total enrollment rates of 71.3% for Taiwanese children, 86.4% for aboriginal children, and 99.6% for Japanese children in Taiwan. As a result, primary school enrollment rates in Taiwan were among the highest in Asia, second only to Japan itself.[8]

ix. LGM-118 Peacekeeper.

“The LGM-118A Peacekeeper, also known as the MX missile (for Missile-eXperimental), was a land-based ICBM deployed by the United States starting in 1986. The Peacekeeper was a MIRV missile; it could carry up to 10 re-entry vehicles, each armed with a 300-kiloton W87 warhead/MK-21 RVs. A total of 50 missiles were deployed after a long and troubled development period.”

Long and troubled indeed:

“The operational missile was first manufactured in February 1984 and was deployed in December 1986 to the Strategic Air Command, 90th Strategic Missile Wing at the Francis E. Warren Air Force Base in Cheyenne, Wyoming in re-fitted Minuteman silos. However, the AIRS was not yet ready and the missiles were deployed with non-operational guidance units. AIRS had 19,000 parts and some of these required as many as 11,000 testing steps.[28] Bogged down in paperwork due to government procurement policies, managers started bypassing official channels and buying replacement parts wherever they could be found, including claims that some of the parts were sourced at Radio Shack. In other cases, managers had created false shell companies to order needed test equipment.[28]

When these allegations were released by 60 Minutes and the Los Angeles Times, the fallout was immediate. Northrop was slapped with a $130 million fine for late delivery, and when they reacted against employees they were countersued in whistleblower suits. The Air Force also admitted that 11 of the 29 missiles deployed were not operational. A Congressional report stated that “Northrop was behind schedule before it even started” and noted that the Air Force knew as early as 1985 that there were “serious system deficiencies as well as a lack of effective progress”.[28] They complained that the Air Force should have come clean and simply pushed back the deployment date, but instead, in order to foster the illusion of progress, the missiles were deployed in a non-operational state.[28]

x. The Middle Ages (featured). Much of this stuff’s known to me of course, but there’s still a lot of good stuff here.

September 22, 2013 Posted by | Biology, Engineering, History, Wikipedia, Zoology | Leave a comment

Stuff (and a few personal remarks)

i. Yesterday I had a very bad and prolonged hypoglycemic episode which lasted hours. I was in a semi-conscious state for a long time before realizing there was a problem, and the situation did not improve much even after intake of significant amounts of dextrose. This is by far the closest I’ve been to a hospital admission for more than a year – I had both severe neurological symptoms and GI-tract involvement. I don’t think I’ve ever been admitted without GI-tract involvement, and this tends to worsen outcomes significantly – it’s hard to reverse a disease process the main treatment of which is putting stuff into your stomach and keeping it there if you have severe nausea and vomit up the stuff you eat.

I really hope that if something like this happens again I’ll be smart enough to actually call an ambulance, or at the very least involve other people so that they can help me if things go really bad. I like to tell myself that I am a very self-reliant and independent person in general – the sort of person who don’t like to ask other people for help and so rarely do. And nobody likes to be seen and judged by others when they’re at their weakest. Combine these facts with the inherent difficulty of assessing when a situation such as this one is sufficiently severe to merit involving other people while you’re having neurological symptoms impacting your thought processes and impairing judgment, and you have the perfect recipe for a situation where you end up making bad decisions and running a major risk of things going very wrong by not getting help. I should really become better at reminding myself (to the extent that it’s possible; as mentioned impaired judgment is a symptom here, so this stuff is not completely under my control) that when I’m in a state like this I’m just a very sick person who very well may need other people’s help simply to survive. Type 1 diabetics die from such hypoglycemic episodes all the time.

Here’s a related post from the past.

ii. (Yet) A(nother) medical lecture:

iii. An event that changed the world:

Here’s more.

iv. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials.


Objectives To determine whether parachutes are effective in preventing major trauma related to gravitational challenge.

Design Systematic review of randomised controlled trials.

Data sources: Medline, Web of Science, Embase, and the Cochrane Library databases; appropriate internet sites and citation lists.

Study selection: Studies showing the effects of using a parachute during free fall.

Main outcome measure Death or major trauma, defined as an injury severity score > 15.

Results We were unable to identify any randomised controlled trials of parachute intervention.

Conclusions As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.”

v. On Being Sane in Insane Places, by David L. Rosenhan.

“At its heart, the question of whether the sane can be distinguished from the insane (and whether degrees of insanity can be distinguished from each other) is a simple matter: Do the salient characteristics that lead to diagnoses reside in the patients themselves or in the environments and contexts in which observers find them? From Bleuler, through Kretchmer, through the formulators of the recently revised Diagnostic and Statistical Manual of the American Psychiatric Association, the belief has been strong that patients present symptoms, that those symptoms can be categorized, and, implicitly, that the sane are distinguishable from the insane. More recently, however, this belief has been questioned. Based in part on theoretical and anthropological considerations, but also on philosophical, legal, and therapeutic ones, the view has grown that psychological categorization of mental illness is useless at best and downright harmful, misleading, and pejorative at worst. Psychiatric diagnoses, in this view, are in the minds of observers and are not valid summaries of characteristics displayed by the observed. [3-5]

Gains can be made in deciding which of these is more nearly accurate by getting normal people (that is, people who do not have, and have never suffered, symptoms of serious psychiatric disorders) admitted to psychiatric hospitals and then determining whether they were discovered to be sane and, if so, how. If the sanity of such pseudopatients were always detected, there would be prima facie evidence that a sane individual can be distinguished from the insane context in which he is found. Normality (and presumably abnormality) is distinct enough that it can be recognized wherever it occurs, for it is carried within the person. If, on the other hand, the sanity of the pseudopatients were never discovered, serious difficulties would arise for those who support traditional modes of psychiatric diagnosis. Given that the hospital staff was not incompetent, that the pseudopatient had been behaving as sanely as he had been out of the hospital, and that it had never been previously suggested that he belonged in a psychiatric hospital, such an unlikely outcome would support the view that psychiatric diagnosis betrays little about the patient but much about the environment in which an observer finds him.

This article describes such an experiment.”

Here’s the wikipedia article about the experiment. Below some more stuff from the paper:

“Eight sane people gained secret admission to 12 different hospitals [6]. […] the pseudopatients were never detected. Admitted, except in one case, with a diagnosis of schizophrenia [10], each was discharged with a diagnosis of schizophrenia “in remission.” The label “in remission” should in no way be dismissed as a formality, for at no time during any hospitalization had any question been raised about any pseudopatient’s simulation. Nor are there any indications in the hospital records that the pseudopatient’s status was suspect. Rather, the evidence is strong that, once labeled schizophrenic, the pseudopatient was stuck with that label. If the pseudopatient was to be discharged, he must naturally be “in remission”; but he was not sane, nor, in the institution’s view, had he ever been sane. […] Length of hospitalization ranged from 7 to 52 days, with an average of 19 days.” […]

“Failure to detect sanity during the course of hospitalization may be due to the fact that physicians operate with a strong bias toward what statisticians call the Type 2 error [5]. This is to say that physicians are more inclined to call a healthy person sick (a false positive, Type 2) than a sick person healthy (a false negative, Type 1). The reasons for this are not hard to find: it is clearly more dangerous to misdiagnose illness than health. Better to err on the side of caution, to suspect illness even among the healthy.” […]

“The following experiment was arranged at a research and teaching hospital whose staff had heard these findings but doubted that such an error could occur in their hospital. The staff was informed that at some time during the following three months, one or more pseudopatients would attempt to be admitted into the psychiatric hospital. Each staff member was asked to rate each patient who presented himself at admissions or on the ward according to the likelihood that the patient was a pseudopatient. A 10-point scale was used, with a 1 and 2 reflecting high confidence that the patient was a pseudopatient.

Judgments were obtained on 193 patients who were admitted for psychiatric treatment. All staff who had had sustained contact with or primary responsibility for the patient — attendants, nurses, psychiatrists, physicians, and psychologists — were asked to make judgments. Forty-one patients were alleged, with high confidence, to be pseudopatients by at least one member of the staff. Twenty-three were considered suspect by at least one psychiatrist. Nineteen were suspected by one psychiatrist and one other staff member. Actually, no genuine pseudopatient (at least from my group) presented himself during this period.

The experiment is instructive. It indicates that the tendency to designate sane people as insane can be reversed when the stakes (in this case, prestige and diagnostic acumen) are high. But what can be said of the 19 people who were suspected of being “sane” by one psychiatrist and another staff member? Were these people truly “sane” or was it rather the case that in the course of avoiding the Type 2 error the staff tended to make more errors of the first sort — calling the crazy “sane”? There is no way of knowing. But one thing is certain: any diagnostic process that lends itself too readily to massive errors of this sort cannot be a very reliable one. […]

It is clear that we cannot distinguish the sane from the insane in psychiatric hospitals. The hospital itself imposes a special environment in which the meaning of behavior can easily be misunderstood. The consequences to patients hospitalized in such an environment — the powerlessness, depersonalization, segregation, mortification, and self-labeling — seem undoubtedly counter-therapeutic.”

September 21, 2013 Posted by | Diabetes, Immunology, Lectures, Medicine, Papers, Personal, Psychology | 2 Comments

The Double Helix (II)

I probably didn’t need to write two posts about this book as it’s not very long, but there was a lot of good stuff in there. I’ve given it four stars on goodreads. The main reason why it doesn’t get five stars is that you actually need to know some stuff about these things in order to understand the stuff that’s going on in the book; ideally a book like this would in my view contain detailed enough descriptions of the various problems they encountered along the way not to leave you any more confused than they were, but perhaps that’s too much to ask from a book like this – I occasionally felt that I had to look up stuff in Russell or at wikipedia in order to figure out the details of what he was talking about, and I’m not really sure you should have to do that when reading a book like this. On the other hand some people might rather say that if a book is sufficiently interesting to have you look up stuff in genetics textbooks or online encyclopedias, then that should truly lead to a feeling of ‘mission accomplished’ on part of the author.. As can probably be inferred from these remarks, I’ve not quoted from the most technical parts of the book – I decided to leave such quotes out, as well as potential major ‘spoiler’-quotes.

Aside from some technical stuff a few places which is not quite as clear as I’d have liked it to be, which arguably is just me asking a bit too much from a book like this, it’s a great read. A few quotes from the last half:

“I pilfered Barnal’s and Fankucken’s paper from the Philosophical Library and brought it up to the lab so that Francis could inspect the TMV X-ray picture. When he saw the blank regions that characterize helical patterns, he jumped into action, quickly spilling out several possible helical TMV structrues. From this moment on, I knew I could no longer avoid actually understanding the helical theory. Waiting until Francis had free time to help me would save me from having to master the mathematics, but only at the penalty of my standing still if Francis was out of the room.”

“The chilling prospect of enduring Francis throughout the remaining years of his tenure as the Cavendish Professor was too much to ask of Bragg or anyone with a normal set of nerves.”

“If a student had made a similar mistake, he would be thought unfit to benefit from Cal Tech’s chemistry faculty. Thus, we could not but initially worry whether Linus‘s model followed from a revolutionary re-evaluation of the acid-base properties of very large molecules. The tone of the manuscript, however, argued against any such advance in chemical theory. […] Linus’s chemistry was screwy.”

“Bertrand and Elizabeth looked pleased with themselves. They had just returned from motoring in a friend’s Rolls to a celebrated country house near Bedford. Their host, an antiquarian architect, had never truckled under to modern civilization and kept his house free of gas and electricity. In all ways possible he maintained the life of an eighteenth-century squire, even to providing special walking sticks for his guests as they accompanied him around his grounds.”

“As the clock went past midnight I was becoming more and more pleased. There had been far too many days when Francis and I worried that the DNA structure might turn out to be superficially very dull, suggesting nothing about either its replication or its function in controlling biochemistry. But now, to my delight and amazement, the answer was turning out to be profoundly interesting. For over two hours i happily lay awake with pairs of adenine residues whirling in front of my closed eyes. Only for brief moments did the fear shoot through me that an idea this good could be wrong. […] My scheme was torn to shreds by the following noon.”

“we had lunch, telling each other that a structure this pretty just had to exist.”

“For a while Francis wanted to expand our note to write at length about the biological implications. But finally he saw the point to a short remark and composed the sentence: ‘It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.'”

Watson & Crick’s original 1953 paper, A Structure for Deoxyribose Nucleic Acid, and some related papers are available here. They’re very short (a few pages) and do not take a lot of time to read.

September 18, 2013 Posted by | Biology, Books, Genetics | Leave a comment

The Double Helix (I)

By James Watson. It’s a classic which I’ve long felt that I had to read at some point. I’m roughly half way through – and so far I really enjoy it. The book may be said to be a lot of things, but it is most certainly not boring.

Some quotes:

“One could not be a successful scientist without realizing that, in contrast to the popular conception supported by newspapers and mothers of scientists, a goodly number of scientists are not only narrow-minded and dull, but also just stupid.”

“Clearly Rosy [Rosalind Franklin – US] had to go or be put in her place. The former was obviously preferable […] Unfortunately, Maurice could not see any decent way to give Rosy the boot. […] The thought could not be avoided that the best home for a feminist was in another person’s lab.”

“I was principally interested in birds and managed to avoid taking any chemistry or physics courses which looked of even medium difficulty. Briefly the Indiana biochemists encouraged me to learn organic chemistry, but after I used a bunsen burner to warm up some benzene, I was relieved from further true chemistry. It was safer to turn out an uneducated Ph.D. than to risk another explosion.”

“I was especially interested to hear the talk on nucleic acids to be given by Randall. At that time almost nothing was published about the possible three-dimensional configurations of a nucleic acid molecule. […] The odds, however, were against any real revelation then. Much of the talk about the three-dimensional structure of proteins and nucleic acids was hot air. Though this work had been going on for over fifteen years, most if not all of the facts were soft. Ideas put forward with conviction were likely to be the products of wild crystallographers who delighted in being in a field where their ideas could not be easily disproved.”

“By the time I was back in Copenhagen, the journal containing Linus’s article had arrived from the States. I quickly read it and immediately reread it. Most of the language was above me, and so I could only get a general impression of his argument. I had no way of judging whether it made sense. The only thing I was sure of was that it was written with style.”

“He had lived alone for several years until Odile, some five years his junior, came to Cambridge and hastened his revolt against the stodginess of the middle classes, which delight in unwicked amusements like sailing and tennis, habits particularly unsuited to the conversational life. […] There was no restraint in Francis’s enthusiasms about young women – that is, as long as they showed some vitality and were distinctive in any way that permitted gossip and amusement.”

“it was possible to get a university degree in biology without learning any genetics. That was not to say that the geneticists themselves provided any intellectual help. You would have thougt that with all their talk about genes they should worry about what they were. Yet almost none of them seemed to take seriously the evidence that genes were made of DNA. This fact was unnecessarily chemical.”

“Though Odile could not follow what we were saying, she was obviously cheered by the fact that Francis was about to bring off his second triumph within the month. If this course of events went on, they would soon be rich and could own a car. At no moment did Francis see any point in trying to simplify the matter for Odile’s benefit. Ever since she had told him that gravity went only three miles into the sky, this aspect of their relationship was set. Not only did she not know any science, but any attempt to put some in her head would be a losing fight against the years of her convent upbringing. The most to hope for was an appreciation of the linear way in which money was measured.”

September 17, 2013 Posted by | Biology, Books, Genetics | 4 Comments

The Developing Heart in Health and Disease

This lecture was interesting, for more than one reason. The lecture is about pediatric cardiology. You’ll learn some stuff about how much things have changed, how far ‘we’ have come. You’ll learn about some new and interesting techniques. But you’ll implicitly also learn a little about how much money is thrown after children who, if costs were not shared quite as widely as is the case now, would never, ever be allowed to survive. There are various ways to argue that such costs are nevertheless justified and I could easily come up with a few, but I’ve worked with cost-efficiency stuff before and the justifications I can come up with for at least some of these procedures look, well, sketchy, to me. A couple of quotes from the lecture:

“she had been spending, oh, at the time where she was nine months old I think she had spent three or four months of her life in the intensive care unit off and on because she was so sick […]
she’s actually now […] four or five years out after the procedure and she’s done well and she’s not yet have had to have another procedure, although she will at some point. […] The problem with these valves is that they’re not living tissue so they don’t grow, and they also tend to deteriorate very quickly, within four or five years. […] even if I had a perfect valve that I could put in my little nine-month old, by the time she was four years of age I’d have to go in and replace it again, and by the time she was, oh, eight-nine years of age, I’d have to go and replace it again. And then maybe if I’m lucky I’ll get one more operation when she’s a teenager, and then finally when she’s an adult I can put in one of those mechanical valves which will last her thirty years. But that’s four or five open heart surgeries.”

After this, he does ask the question if there isn’t a better way to do things – and they’re working on that now. But there isn’t a better way to do things now, and it seems like these kids actually do get all those operations. This study from 2011 (page 6) provides average baseline costs of roughly $5.000 per day of PICU (pediatric intensive care unit) admission; this should give you some idea of how much money we’re actually talking about when we’re discussing 3 month long stays in a PICU. Cost-estimates of open-heart surgeries are not easy to find, but I think it’s safe to say that those aren’t exactly cheap either.

Here’s the lecture:

September 16, 2013 Posted by | Cardiology, Lectures, Medicine | Leave a comment

The Incas and their Ancestors: The Archaeology of Peru (II)

Here’s my first post about the book. I gave it 3 stars on goodreads. This is my 49th completed book this year.

The last two-thirds or so of the book actually doesn’t have a lot of stuff about the Incas – that part of the book mostly deals with the people who came before them. I knew very little about this part of South American prehistory, so I learned a lot and it was quite interesting.

I should note that in the Epilogue (last three pages) Moseley can’t stop himself from displaying some of that bottled-up hatred he clearly has towards the later colonial rulers and the current “international financial institutions” that ‘indirectly govern’ “a denigrated ethnic underclass”. Just to make clear – if there’d been just two sentences like that in the first 10 pages of the book, I’d have slammed the book shut and given it one star on goodreads. I have zero tolerance for overt politicizing in books like these. But there weren’t any such sentences to be found – the book is about the archaeology of prehistoric Peru and surrounding areas, and he keeps his mouth shut about ‘other stuff’ until the very last few pages, where you can sort of forgive such digressions. In the last couple of pages he incidentally also repeats a problematic claim from the beginning: “The era opened when Tahuantinsuyu was arguably the largest nation on earth”. This sentence really annoyed me. Has he heard about the Ottoman Empire? The Ming Dynasty? The Grand Duchy of Moscow? For those who haven’t, here are a few numbers:

Inca Empire in 1527: 2,000,000 km².
Ottoman Empire in 1520: Roughly 4,000,000 km²
Grand Duchy of Moscow in 1533: Roughly 2,800,000 km².

Wikipedia doesn’t have an area estimate for the Ming Dynasty during the 1500s, but in 1403 it was estimated at 6,500,000 km² and it didn’t lose more than two-thirds of its total area during the intervening 100-150 years (the population doubled during that century). The estimated Ming population around the year 1500 incidentally was 125 million people (Inca empire: 20 million).

Authors of books like this one tend to feel very strongly about the things they write about and sometimes that means they end up exaggerating certain things. The rest of the book is fine and it’s the only place where I’m aware that he does it – but when I see stuff like that, it annoys me a lot. There’s no doubt the Inca state was a major international player, you don’t need to add inaccurate claims to the mix to impress me.

All that said, most of the book is solid (and interesting!) work. In the stuff below I’ve mostly focused on agricultural developments in part because that’s much easier to blog. There’s a lot of stuff about the platform mounds, sunken courts, ceremonial architecture, sanctuaries, etc. in the book, and in order not to completely disregard all that stuff I decided to add some links at the bottom. Here are also a few pictures:


450px-Sechín_Archaeological_site_-_relief_(warrior)(image credit: Wikipedia)


(image credit: Wikipedia)

Anyway, below some stuff from the last five chapters:

“The spread of intensive farming and pottery followed the path of least resistance, moving from low to high and moist to dry environments. In the well-watered tropical north of Colombia and Ecuador, agriculture was adopted well before 3000 BC. However, extension down the arid Cordillera lagged, and only after an episode of dusty, and apparently dry, climatic times did farming take hold in northern and central Peru around 1800 BC. Further south there was again a lag until 1600 BC when rainfall increased in the Titicaca region and supported the rise of agropastoralism. From here it still took many hundreds of years for farm plants and pottery to diffuse into the hyper-arid environments of San Pedro de Atacama and the very dry Chilean coast. […] As mountain populations decreased their dependence on wild resources and increased their reliance on cultivation, they were slowly drawn away from the higher elevations to lower settings where warmer temperatures and milder conditions favoured plant tending in the bottomlands of sierra drainages. A gradual downward shift in the locations of camps and residential sites is well-documented during pre-pottery times […] human colonization of the Andes was a gradual matter of sedentary parental communities giving rise to more mobile daughter colonies seeking new terrain […] Andean people experienced a many-fold increase in their numbers during the Preceramic Period. In the sierra, residential sites became more numerous and scattered, on the coast fisherfolk filled in the littoral around sources of potable water, and large civic-ceremonial complexes arose in the mountains and deserts of northern and central Peru.” […]

“In many valleys it seems that irrigation developed along the path of least resistance, and most canal systems were situated well inland. Developments began in canyons and valley necks where river gradients are relatively steep […] Reclamation then advanced downstream where shallow gradients required greater investments in canal construction. In many valleys land immediately behind the coast was either never irrigated or only reclaimed very late. Because canal irrigation pulls farmers inland, the Initial Period is marked by split patterns of residence, with fisherfolk living along the littoral and farmers settling inland. […] less than 5 percent of the desert that is farmed today could be easily reclaimed by individual effort, and this condition certainly worked against the rise of independent farmers during the Initial Period. Preceramic economies supported the evolution of corporate organizations capable of executing large building projects.” […]

“In the Ayacucho region Initial Period settlements have yielded pottery assemblages, called Andamarca and Wichqana, with limited decoration and few suggestions of tropical influence. The Wichqana site has a ceremonial structure […] associated with the buried skulls of decapitated women. In the nearby Andahuaylas Valley, excavations in the Muyu Moqo sector of the Waywaka site produced a 3,440-year-old stone bowl containing metalworking tools and gold beated into thin foil. This is the earliest evidence of precious metalworking in the Andes.” [Severed heads? Gold? What’s not to like?]

“In the beginning, mountain agropastoralism and desert irrigation fostered economic boom times with people spreading into under-exploited niches, prospering and increasing their numbers. Yet growth inevitably slowed, and by the time of Christ refinements of Arid Montane and Maritime-Oasis adaptions had led to the filling-in of easily exploited habitats and further agrarian expansion required substantial investment. […] now governance was in the hands of an elite class, the kuraka, who claimed special descent from founding figures. This fostered great elaboration of ancestor veneration among commoners in general and elites in particular. […] competition and hostilities increased as easily farmed land was filled in by growing populations and during episodes of drought” […]

“Geoglyphs at Nazca and elsewhere certainly served more than one function. Calendrial significance for the lines has long been suspecteed, but not yet demonstrated. The great concentration of figures on the Nazca pampa represents by far the largest cultural artifacts of the region’s ancient inhabitants. Similar to the many mounds at Cahuachi, they are numerous and impressive, but do not represent great expenditures of energy. Although the geoglyphs are technically similar, each seems to have been created separately, used for a time, and then forgotten. New figures cross old ones in amazing confusion, and the works were obviously not part of a larger, centralized conception planned by one mind at one time.” […]

“Triggered by deep drought, the Middle Horizon was an era of punctuated cultural change as old empires withered and new ones arose. […] Technically the horizon dates between AD 600 and 1000 in the Ica Valley. Yet it was set in motion in AD 562 when rainfall began a 25-30 percent plunge that lasted until AD 594. This was the most pronounced Andean rainfall abnormality of the last 1,500 years […] Famine certainly occured because agrarian systems in many settings stretched beyond their modern limits. We can infer that the productivity of highland rainfall farming declined proportionally by 25-30 percent and that the productivity of desert irrigation declined disproportionally by at least twice as much due to dry mountain soils absorbing scant runoff moisture. Consequently coastal populations were more severely disadvantaged than their sierra counterparts. During drought, however, both populations were ill-equipped to deal with normal disasters, such as large-magnitude earthquakes and El Niño crises […] Huarpa people in the Ayacucho area were among the first to terrace and irrigate inclined terrain. […] Building such a reclamation system required substantially more labor than other communities were investing in agricultural works at the time. Nonetheless, such investment gave Huari distinct economic advantages over its neighbors, and in a sense preadapted it to weather the great drought. […] The demise of Huari remains undated and not understood, but the original spread of its appealing ideology, featuring a resurrected Staff God, was farreaching due to accompanying agrarian innovations. By introducing mountain-slope, terrace farming to many highland regions Huari preadapted sierra populations to drought […] intensification of pastoralism was an important response to drought.” […]

Tiwanaku people considered cranial deformation a mark of beauty and bound the heads of babies to shape their skull growth. Individuals in a cemetery shared the same deformation pattern, and patterns varied from one Omo graveyard to another.” [And you thought foot binding was bad! (okay, foot binding is bad, but…] […]

“beginning around AD 1100, four centuries of climate change saw precipitation decline and reach a 10-15 percent below-normal nadir shortly after AD 1300. Drought endured until AD 1500, and we can see a range of human responses to the waxing and waning of protracted stress. Sierra populations dispersed to higher altitudes where rainfall could still support farming, albeit with large investments in terracin mountain slopes. There was also migration into the wet eastern face of the Cordillera, where tarracing was again essential. Desert farmers fared very poorly […] the pre-Inca altiplano was a landscape of combative señoríos that the lords of Cuzco played off against one another and conquered in piecemeal fashion. […] The Incas conquered the lake region as drought waned and gave way to exceptionally wet conditions that permitted farming to be renewed at lower, less hostile elevations. Consequently, Tahuantinsuyu often moved people out of fortified hilltops and resettled them in low-lying localities that gave better yields, afforded easier political control and were closer to the imperial highway system. […] Pushing north as dry times waned, Cuzco’s forces often encountered little organized opposition. […] In overview, from northern Chile through northern Peru drought prompted mountain people to move higher, as well as eastward where rainfall could still sustain farming and herding. Opening these vast reaches of the Cordillera to intensive production required extensive investments in terracing and agricultural infrastructure, but they sustained significant population growth in spite of dry times. This changed the demographic balance of power in favor of the sierra, as coastal populations wilted in the wake of protracted drought.” […]

“It is doubtful that combat and blood sacrifice permeated everyday life. More likely, iconographic themes expressed ideological rituals that were scheduled and enacted over the course of an annual ceremonial calender, much like the Inca’s sacramental almanac.” [Note that people in power didn’t suddenly start all that human sacrifice stuff when the Inca’s came into power. This stuff was tradition at that point and had been for a while.]

Links: MocheEl Paraíso, Huaca del Sol. Chan ChanChavín de Huántar. Lima Culture. Nazca Lines. Pachacamac. Wari culture, Pikillaqta.

September 14, 2013 Posted by | Anthropology, Archaeology, Books | Leave a comment

Random stuff

i. I went to my first Mensa meeting a couple of days ago. It was nice, I felt very welcome. When I’m to participate in such a ‘new/unknown type of social event’, I always think a bit beforehand about how to approach things and how to handle various contingencies – below a couple of remarks I made in a skype conversation shortly before the meeting:

“I have been wondering what [would be] the best communications strategy today. I think I’ll probably just keep in the background, to the extent I’m allowed to do that, and observe what’s going on. It’s what I usually do when I’m in groups with lots of people. […]

On the other hand I should also use such activities to improve my social skills, and that involves actually talking to- and interacting with other people.. […]

And there’s a path-dependence aspect to consider as well. People usually categorize others and put them into some box quite quickly. If I’m put into the antisocial don’t-want-to-talk-with-others box from the start, it might be hard to break out of that later on.”

In the end I actually ended up talking myself into thinking that I should try to participate in conversations as much as possible, and try not to hold back like I usually do. As I put it in a later Skype conversation, “I actually made a point out of being significantly more verbose than I normally am. Maybe it was a bad strategic choice.”

Well, we’ll see. This was certainly not my last Mensa meeting.

ii. A look over my shoulder:



On a very slightly related point, I just started reading Tom Apostol’s Introduction to Analytic Number Theory.

iii. Another Stanford lecture:

You can easily skip the first 6 minutes without missing out on anything important. I think the first lecturer goes a bit overboard towards the end, and in general I’d say I preferred Erik Knudsen’s part of the lecture. I found it annoying that it was sometimes hard to figure out which figures or elements of a slide they were actually talking about – they’ll point to a specific part of a slide, but you can’t see where they’re pointing so you have no idea which dendrite ‘this dendrite’ actually is, and even though you can usually infer it it’s still confusing and suboptimal.

I know most readers don’t actually watch these lectures, so a couple of points to take with you that don’t require you to know much about the details:

“Human speech is about 500 to 3000 Hz. […] the low-frequency part of speech [are] vowels […] they’re lower tones […] Consonants […] give the sense to speech [and are higher frequency sounds]. And what happens as people lose high-frequency hearing [is] they become confused between the consonant sounds of speech. So hope and soap and cope begin to run together.” (I didn’t know this)

“the cues that you use to localise sounds in space are largely based on inter-oral differences in the timing and the level or intensity of sound in your two ears.”

They also argue (around the 1:30 mark) that given how important binaural interactions are, people shouldn’t wear hearing aids on just one ear.

iv. Schooling Is Not Education! – A Report of the Center for Global Development Study Group on Measuring Learning Outcomes. This point was also emphasized in one of my previous courses and I think I’ve covered this stuff before, but I haven’t linked to this paper yet. Some stuff from the paper:

“In India, national survey evidence reveals that only about one-third of children in grade 5 can perform long division, and one-third cannot perform two-digit subtraction.[11] Nearly one-half of grade 5 students cannot read a grade 2 text and one in five cannot follow a grade 1 text.[12] Sixty percent of Indian children enrolled in grade 8 cannot use a ruler to measure a pencil. Only 27 percent of Indian children who complete primary school can read a simple passage, perform division, tell time, and handle money, although students should master each of these skills by the end of the second year of school.[13] These statistics compare starkly with the official 81 percent youth literacy rate reported by the United Nations Education, Scientific and Cultural Organization (UNESCO).[14]

Similar findings have emerged elsewhere.[15] […]

A flat learning trajectory through successive school grades is reflected in low test scores among older students. Using several sources of recent data from India, the Center for Global Development’s Lant Pritchett examined the number of repeat questions that fourth, sixth, and eighth graders answered correctly. For language, the percentage climbs from 51 to 57 percent between fourth and eighth grades. For math, it climbs from 36 to 53 percent. This suggests that it would take 32 years of schooling for 90 percent of all students to correctly answer a language question that more than half of all fourth graders already correctly answered. India is hardly unique in its flat learning trajectories. Studies of the impact of education on learning in Bangladesh in the 1990s found that three additional years of schooling had no appreciable impact on learning achievement.[18]

At higher levels, results are perhaps even more worrying. Internationally comparable mathematics tests under the Trends in International Mathematics and Science Study (TIMSS) suggest that the average eighth grader in Ghana has a test score that would place her in the bottom 0.2 percent of US students. Even in considerably richer developing countries, the learning gap is large: the average Chilean student would be in the bottom 6.4 percent of US students, based on TIMSS scores. [19]”

Fig 3

Fig 4

“Until school systems can guarantee that students will learn while sitting in class, it may even be counterproductive to encourage longer periods of universal education.[24] In fact, expanded enrollments can actually harm overall learning outcomes if quality cannot be broadly maintained. While grade 8 enrollment in India increased from 82 to 87 percent from 2006 to 2011, ASER tests suggests the fraction of grade 8 children who could do division fell from 70 percent to 57 percent. This suggests that fewer school-age children actually learned division, despite climbing enrollments.” […]

“on an average school day, 11 percent of teachers are absent in Peru, 16 percent are absent in Bangladesh, and 27 percent are absent in Uganda.[29] Even when they are present, teachers may make limited efforts to create a friendly learning environment. ASER’s observation of rural education practices in 1,075 classrooms across five Indian states reveals that in only about a quarter of classrooms was a student witnessed asking a question. Other child-friendly practices […] were even less common.

Direct methods to improve teacher attendance and effort have improved test scores with mixed results,[31] as has the use of contract teachers.[32] The importance of systemic issues is demonstrated by the fact that interventions that successfully improve teacher performance in one system can fail when applied elsewhere. For example, Paul Atherton and Geeta Kingdon show that students taught by contract teachers in public schools in Uttar Pradesh learned about twice as much per year as those taught by civil service teachers.[33] At the same time, an attempt to scale contract teachers in Kenya revealed that contract teachers only influenced test scores when hired by a nongovernmental organization, not the Kenyan government.[34] A randomized study in the Indian state of Andhra Pradesh suggests that bonuses for teachers based on exam results can improve outcomes.[35] In Kenya, however, teacher performance incentives related to test scores increased student learning only in the short run.[36] […]

“It is perhaps not surprising that there is a gap between schooling and learning, and that education reform is difficult. Schools and education systems are about a lot more than learning. For students, schools are also about signaling innate intelligence, status, and social networks. For parents, they are also a form of daycare. For teachers, they are a stable source of income. For governments, schools are also about socialization, employment, and rent generation.[45] A complex story of political economy lies behind the schooling-learning gap. Given the complex political economy of systemic reform, and the considerable diversity in existing educational systems around the world, solutions to learning stagnation will vary immensely across countries.”

Fig 5

September 12, 2013 Posted by | Books, Economics, education, Lectures, Mathematics, Medicine, Personal | Leave a comment

Wikipedia articles of interest

i. Scattered disc (featured).

“The scattered disc (or scattered disk) is a distant region of the Solar System that is sparsely populated by icy minor planets, a subset of the broader family of trans-Neptunian objects. The scattered-disc objects (SDOs) have orbital eccentricities ranging as high as 0.8, inclinations as high as 40°, and perihelia greater than 30 astronomical units (4.5×109 km; 2.8×109 mi). These extreme orbits are believed to be the result of gravitational “scattering” by the gas giants, and the objects continue to be subject to perturbation by the planet Neptune. While the nearest distance to the Sun approached by scattered objects is about 30–35 AU, their orbits can extend well beyond 100 AU. This makes scattered objects “among the most distant and cold objects in the Solar System”.[1] The innermost portion of the scattered disc overlaps with a torus-shaped region of orbiting objects traditionally called the Kuiper belt,[2] but its outer limits reach much farther away from the Sun and farther above and below the ecliptic than the belt proper.[a]

Because of its unstable nature, astronomers now consider the scattered disc to be the place of origin for most periodic comets observed in the Solar System, with the centaurs, a population of icy bodies between Jupiter and Neptune, being the intermediate stage in an object’s migration from the disc to the inner Solar System.[4] Eventually, perturbations from the giant planets send such objects towards the Sun, transforming them into periodic comets. Many Oort-cloud objects are also believed to have originated in the scattered disc. […]

The Kuiper belt is a relatively thick torus (or “doughnut”) of space, extending from about 30 to 50 AU[18] comprising two main populations of Kuiper belt objects (KBOs): the classical Kuiper-belt objects (or “cubewanos”), which lie in orbits untouched by Neptune, and the resonant Kuiper-belt objects; those which Neptune has locked into a precise orbital ratio such as 3:2 (the object goes around twice for every three Neptune orbits) and 2:1 (the object goes around once for every two Neptune orbits). These ratios, called orbital resonances, allow KBOs to persist in regions which Neptune’s gravitational influence would otherwise have cleared out over the age of the Solar System, since the objects are never close enough to Neptune to be scattered by its gravity. Those in 3:2 resonances are known as “plutinos“, because Pluto is the largest member of their group, whereas those in 2:1 resonances are known as “twotinos“.

In contrast to the Kuiper belt, the scattered-disc population can be disturbed by Neptune.[19] […] The MPC […] makes a clear distinction between the Kuiper belt and the scattered disc; separating those objects in stable orbits (the Kuiper belt) from those in scattered orbits (the scattered disc and the centaurs).[10] However, the difference between the Kuiper belt and the scattered disc is not clearcut, and many astronomers see the scattered disc not as a separate population but as an outward region of the Kuiper belt.”

ii. Bobcat (featured).


“The bobcat (Lynx rufus) is a North American mammal of the cat family Felidae, appearing during the Irvingtonian stage of around 1.8 million years ago (AEO).[3] With 12 recognized subspecies, it ranges from southern Canada to northern Mexico, including most of the continental United States. The bobcat is an adaptable predator that inhabits wooded areas, as well as semidesert, urban edge, forest edges, and swampland environments. It persists in much of its original range, and populations are healthy.

With a gray to brown coat, whiskered face, and black-tufted ears, the bobcat resembles the other species of the mid-sized Lynx genus. It is smaller on average than the Canada lynx, with which it shares parts of its range, but is about twice as large as the domestic cat. It has distinctive black bars on its forelegs and a black-tipped, stubby tail, from which it derives its name.

Though the bobcat prefers rabbits and hares, it will hunt anything from insects, chickens, and small rodents to deer. Prey selection depends on location and habitat, season, and abundance. Like most cats, the bobcat is territorial and largely solitary […]

The bobcat is believed to have evolved from the Eurasian lynx, which crossed into North America by way of the Bering Land Bridge during the Pleistocene, with progenitors arriving as early as 2.6 mya.[5] The first wave moved into the southern portion of North America, which was soon cut off from the north by glaciers. This population evolved into modern bobcats around 20,000 years ago. A second population arrived from Asia and settled in the north, developing into the modern Canada lynx.[4] Hybridization between the bobcat and the Canada lynx may sometimes occur […]

The bobcat has long been valued both for fur and sport; it has been hunted and trapped by humans, but has maintained a high population, even in the southern United States, where it is extensively hunted. Indirectly, kittens are most vulnerable to hunting given their dependence on an adult female for the first few months of life. […] The IUCN lists it as a species of “least concern“, noting it is relatively widespread and abundant”

iii. Luis Walter Alvarez (good article). A remarkable man who lived a remarkable life:

Luis W. Alvarez (June 13, 1911 – September 1, 1988) was an American experimental physicist and inventor, who was awarded the Nobel Prize in Physics in 1968. […]

After receiving his PhD from the University of Chicago in 1936, Alvarez went to work for Ernest Lawrence at the Radiation Laboratory at the University of California, Berkeley. Alvarez devised a set of experiments to observe K-electron capture in radioactive nuclei, predicted by the beta decay theory but never observed. He produced 3H using the cyclotron and measured its lifetime. In collaboration with Felix Bloch, he measured the magnetic moment of the neutron.

In 1940 Alvarez joined the MIT Radiation Laboratory, where he contributed to a number of World War II radar projects […] Alvarez spent a few months at the University of Chicago working on nuclear reactors for Enrico Fermi before coming to Los Alamos to work for Robert Oppenheimer on the Manhattan project. Alvarez worked on the design of explosive lenses, and the development of exploding-bridgewire detonators. As a member of Project Alberta, he observed the Trinity nuclear test from a B-29 Superfortress, and later the bombing of Hiroshima from the B-29 The Great Artiste. […]

After the war Alvarez was involved in the design of a liquid hydrogen bubble chamber that allowed his team to take millions of photographs of particle interactions, develop complex computer systems to measure and analyze these interactions, and discover entire families of new particles and resonance states. This work resulted in his being awarded the Nobel Prize in 1968. He was involved in a project to x-ray the Egyptian pyramids to search for unknown chambers. He analyzed film footage of the Kennedy assassination, and with his son, geologist Walter Alvarez, developed the Alvarez hypothesis which proposes that the extinction event that wiped out the dinosaurs was the result of an asteroid impact. […]

As a result of his radar work and the few months spent with Fermi, Alvarez arrived at Los Alamos in the spring of 1944, later than many of his contemporaries. The work on the “Little Boy” (a uranium bomb) was far along so Alvarez became involved in the design of the “Fat Man” (a plutonium bomb). The technique used for uranium, that of forcing the two sub-critical masses together using a type of gun, would not work with plutonium because the high level of background spontaneous neutrons would cause fissions as soon as the two parts approached each other, so heat and expansion would force the system apart before much energy has been released. It was decided to use a nearly critical sphere of plutonium and compress it quickly by explosives into a much smaller and denser core, a technical challenge at the time.[27]

To create the symmetrical implosion required to compress the plutonium core to the required density, thirty two explosive charges were to be simultaneously detonated around the spherical core. Using conventional explosive techniques with blasting caps, progress towards achieving simultaneity to within a small fraction of a microsecond was discouraging. Alvarez directed his graduate student, Lawrence H. Johnston, to use a large capacitor to deliver a high voltage charge directly to each explosive lens, replacing blasting caps with exploding-bridgewire detonators. The exploding wire detonated the thirty two charges to within a few tenths of a microsecond. The invention was critical to the success of the implosion-type nuclear weapon.”

iv. Nuclear binding energy. The ‘main article’ about binding energy is less detailed, but if you’re interested in this stuff you may want to check that one out too. It’s clearly still ‘a work in progress’, but there’s some good stuff here. From the article:

Nuclear binding energy is the energy required to split a nucleus of an atom into its component parts. The component parts are neutrons and protons, which are collectively called nucleons. The binding energy of nuclei is always a positive number, since all nuclei require net energy to separate them into individual protons and neutrons. Thus, the mass of an atom’s nucleus is always less than the sum of the individual masses of the constituent protons and neutrons when separated. This notable difference is a measure of the nuclear binding energy, which is a result of forces that hold the nucleus together. Because these forces result in the removal of energy when the nucleus is formed, and this energy has mass, mass is removed from the total mass of the original particles, and the mass is missing in the resulting nucleus. This missing mass is known as the mass defect, and represents the energy released when the nucleus is formed.

The term nuclear binding energy may also refer to the energy balance in processes in which the nucleus splits into fragments composed of more than one nucleon, and in this case the binding energies for the fragments, as compared to the whole, may be either positive or negative, depending on where the parent nucleus and the daughter fragments fall on the nuclear binding energy curve. If new binding energy is available when light nuclei fuse, or when heavy nuclei split, either of these processes result in releases of the binding energy. This energy, available as nuclear energy, can be used to produce electricity (nuclear power) or as a nuclear weapon. When a large nucleus splits into pieces, excess energy is emitted as photons (gamma rays) and as kinetic energy of a number of different ejected particles (nuclear fission products).

Total mass is conserved throughout all such processes, so long as the system is isolated. During each nuclear transmutation, the “mass defect” mass is relocated to, or carried away by, other particles that are no longer a part of the original nucleus.

The nuclear binding energies and forces are on the order of a million times greater than the electron binding energies of light atoms like hydrogen.[1]

The mass defect of a nucleus represents the mass of the energy of binding of the nucleus, and is the difference between the mass of a nucleus and the sum of the masses of the nucleons of which it is composed. […]

Small nuclei that are larger than hydrogen can combine into bigger ones and release energy, but in combining such nuclei, the amount of energy released is much smaller compared to hydrogen fusion. The reason is that while the overall process releases energy from letting the nuclear attraction do its work, energy must first be injected to force together positively charged protons, which also repel each other with their electric charge.[5]

For elements that weigh more than iron (a nucleus with 26 protons), the fusion process no longer releases energy. In even heavier nuclei energy is consumed, not released, by combining similar sized nuclei. With such large nuclei, overcoming the electric repulsion (which affects all protons in the nucleus) requires more energy than what is released by the nuclear attraction (which is effective mainly between close neighbors). […]

Nuclei heavier than uranium spontaneously break up too quickly to appear in nature, though they can be produced artificially. Generally, the heavier the nuclei are, the faster they spontaneously decay.[5]

Iron nuclei are the most stable nuclei (in particular iron-56), and the best sources of energy are therefore nuclei whose weights are as far removed from iron as possible. One can combine the lightest ones—nuclei of hydrogen (protons)—to form nuclei of helium, and that is how the Sun generates its energy. Or else one can break up the heaviest ones—nuclei of uranium—into smaller fragments, and that is what nuclear power reactors do.[5]


v. Surrender of Japan (featured). Lots of good stuff here I did not know.

vi. Spinal cord injury.

“A spinal cord injury (SCI) refers to any injury to the spinal cord that is caused by trauma instead of disease.[1] Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence.[2][3] Spinal cord injuries are described at various levels of “incomplete”, which can vary from having no effect on the patient to a “complete” injury which means a total loss of function.

Treatment of spinal cord injuries starts with restraining the spine and controlling inflammation to prevent further damage. The actual treatment can vary widely depending on the location and extent of the injury. In many cases, spinal cord injuries require substantial physical therapy and rehabilitation, especially if the patient’s injury interferes with activities of daily life.

Spinal cord injuries have many causes, but are typically associated with major trauma from motor vehicle accidents, falls, sports injuries, and violence. Research into treatments for spinal cord injuries includes controlled hypothermia and stem cells, though many treatments have not been studied thoroughly and very little new research has been implemented in standard care. […]

In a “complete” spinal injury, all function below the injured area are lost. In an “incomplete” injury, some or all of the functions below the injured area may be unaffected. If the patient has the ability to contract the anal sphincter voluntarily or to feel a pinprick or touch around the anus, the injury is considered to be incomplete. The nerves in this area are connected to the very lowest region of the spine, the sacral region, and retaining sensation and function in these parts of the body indicates that the spinal cord is only partially damaged. An incomplete spinal cord injury involves preservation of motor or sensory function below the level of injury in the spinal cord.[8] […]

Spinal cord injuries frequently result in at least some incurable impairment even with the best possible treatment. In general, patients with complete injuries recover very little lost function and patients with incomplete injuries have more hope of recovery. Some patients that are initially assessed as having complete injuries are later reclassified as having incomplete injuries.

The place of the injury determines which parts of the body are affected. The severity of the injury determines how much the body will be affected. Consequently, a person with a mild, incomplete injury at the T5 vertebrae will have a much better chance of using his or her legs than a person with a severe, complete injury at exactly the same place in the spine.

Recovery is typically quickest during the first six months, with very few patients experiencing any substantial recovery more than nine months after the injury.[43] […]

In the United States, the incidence of spinal cord injury has been estimated to be about 40 cases (per 1 million people) per year or around 12,000 cases per year.[44][45] The most common causes of spinal cord injury are motor vehicle accidents, falls, violence and sports injuries.[45] The average age at the time of injury has slowly increased from a reported 29 years of age in the mid-1970s to a current average of around 40. Over 80% of the spinal injuries reported to a major national database occurred in males.[46] In the United States there are around 250,000 individuals living with spinal cord injuries.[25][47]

vii. Rhabdomyolysis (featured).

Rhabdomyolysis /ˌræbdɵmˈɒlɨsɪs/ is a condition in which damaged skeletal muscle tissue (Greek: ῥαβδω rhabdo- striped μυς myo- muscle) breaks down (Greek: λύσις –lysis) rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure. The severity of the symptoms, which may include muscle pains, vomiting and confusion, depends on the extent of muscle damage and whether kidney failure develops. The muscle damage may be caused by physical factors (e.g. crush injury, strenuous exercise), medications, drug abuse, and infections. Some people have a hereditary muscle condition that increases the risk of rhabdomyolysis. The diagnosis is usually made with blood tests and urinalysis. The mainstay of treatment is generous quantities of intravenous fluids, but may include dialysis or hemofiltration in more severe cases.[1][2]

Rhabdomyolysis and its complications are significant problems for those injured in disasters such as earthquakes and bombings. […]

Damage to skeletal muscle may take various forms. Crush injuries and other physical causes damage muscle cells directly or interfere with their blood supply, while non-physical causes interfere with muscle cell metabolism. When damaged, muscle tissue rapidly fills with fluid from the bloodstream, including sodium ions. The swelling itself may lead to destruction of muscle cells, but those cells that survive are subject to various disruptions that lead to rise in intracellular calcium ions; the accumulation of calcium in the sarcoplasmic reticulum leads to continuous muscle contraction and depletion of ATP, the main carrier of energy in the cell.[3][7] ATP depletion can itself lead to uncontrolled calcium influx.[2] The persistent contraction of the muscle cell leads to breakdown of intracellular proteins and disintegration of the cell.[2]

Neutrophil granulocytes—the most abundant type of white blood cell—enter the muscle tissue, producing an inflammatory reaction and releasing reactive oxygen species,[3] particularly after crush injury.[2] Crush syndrome may also cause reperfusion injury when blood flow to decompressed muscle is suddenly restored.[2]

The swollen, inflamed muscle may directly compress structures in the same fascial compartment, causing compartment syndrome. The swelling may also further compromise blood supply into the area. Finally, destroyed muscle cells release potassium ions, phosphate ions, the heme-containing protein myoglobin, the enzyme creatine kinase and uric acid (a breakdown product of purines from DNA) into the blood. Activation of the coagulation system may precipitate disseminated intravascular coagulation.[3] High potassium levels may lead to potentially fatal disruptions in heart rhythm. Phosphate binds to calcium from the circulation, leading to low calcium levels in the blood.[3]

Rhabdomyolysis may cause renal failure by several mechanisms. The most important problem is the accumulation of myoglobin in the kidney tubules.[2][3][7] […]

The prognosis depends on the underlying cause and whether any complications occur. Rhabdomyolysis complicated by acute kidney impairment in patients with traumatic injury may have a mortality rate of 20%.[1] Admission to the intensive care unit is associated with a mortality of 22% in the absence of acute kidney injury, and 59% if renal impairment occurs.[2] Most people who have sustained renal impairment due to rhabdomyolysis fully recover their renal function.[2] […]

Up to 85% of people with major traumatic injuries will experience some degree of rhabdomyolysis.[1] Of those with rhabdomyolysis, 10–50% develop acute kidney injury.[1][2] […] Rhabdomyolysis accounts for 7–10% of all cases of acute kidney injury in the U.S.[2][7]

September 11, 2013 Posted by | Astronomy, Biology, History, Medicine, Nephrology, Neurology, Physics, Wikipedia, Zoology | Leave a comment

The (Honest) Truth about Dishonesty

Here’s the link. It’s an easy read, the kind of book where I’m at one page per minute or more. I gave it two stars on goodreads. It doesn’t have a lot of new stuff I didn’t already know and the coverage is very superficial. I already knew about Becker’s model of crime, the Benjamin Franklin effect, the Israeli parole board study, the ego depletion theory, the broken window hypothesis, etc. – and even though it increases reading speed I don’t really like reading books which cover a lot of stuff I already know. At least not unless I feel that I’m also learning a lot of new stuff, or perhaps make new connections between different stuff I already know – and I didn’t feel that while reading this book.

I don’t trust all the inferences made, and I think some of the findings are quite shaky – especially, but certainly not only, the ones about a potential link between creativity and dishonesty in chapter 7. I simply don’t believe one of the findings described in the book – that the amount of money to be gained from cheating does not affect the level of cheating. I think this finding is just a consequence of the experimental setups applied, and that it would break down if you increase the monetary amounts involved. $10 is peanuts to a US college student, try raising the stakes to $1.000 or $10.000 and see what happens. I am aware that one way to increase monetary amounts dramatically in such experimental settings without drastically increasing research costs along the way is to conduct such research in poorer countries than the US (one dollar is worth a lot more in Bangladesh than it is in the US), but I don’t know if people have actually done this at this point. I don’t really care enough about this research to find out, but if any of the readers know more about this do let me know in the comments.

I wouldn’t recommend the book and I take this book to make yet another strong case for avoiding popular science books. It has way more pages than were necessary to cover the material actually covered.

A little bit of stuff from the book below:

“Becker’s […] approach to dishonesty are comprised of three basic elements: (1) the benefit that one stands to gain from the crime; (2) the probability of getting caught; and (3) the expected punishment if one is caught.” (Here’s a link. Incidentally some of this stuff was covered in one of my previous courses.)

“the central thesis is that our behaviour is driven by two opposing motivations. […] we want to view ourselves as honest, honorable people. We want to be able to look at ourselves in the mirror and feel good about ourselves […] On the other hand, we want to benefit from cheating and get as much money as possible […] as long as we cheat by only a little bit, we can benefit from cheating and still view ourselves as marvelous human beings. […] In short, I believe that all of us continuously try to identify the line where we can benefit from dishonesty without damaging our own self-image.”

“When the rules are somewhat open to interpretation, when there are gray areas, and when people are left to score their own performance—even honorable games such as golf can be traps for dishonesty.”

“when our deliberate reasoning ability is occupied, the impulsive system gains more control over our behavior. […] The basic idea behind ego depletion is that resisting temptation takes considerable effort and energy. […] Each of the decisions we make to avoid temptation takes some degree of effort […] and we exhaust our willpower by using it over and over […] experiments with depletion suggest that, in general, we would be well served to realize that we are continually tempted throughout the day and that our ability to fight this temptation weakens with time and accumulated resistance.”

“The basic idea behind self-signaling is that despite what we tend to think, we don’t have a very clear notion of who we are. We generally believe that we have a privileged view of our own preferences and character, but in reality we don’t know ourselves that well (and definitely not as well as we think we do). Instead, we observe ourselves in the same way we observe and judge the actions of other people—inferring who we are and what we like from our actions. […] We may not always know exactly why we do what we do, choose what we choose, or feel what we feel. But the obscurity of our real motivations doesn’t stop us from creating perfectly logical-sounding reasons for our actions, decisions, and feelings.”

“We have an incredible ability to distance ourselves in all kinds of ways from the knowledge that we are breaking the rules, especially when our actions are a few steps removed from causing direct harm to someone else.”

“In many areas of life, we look to others to learn what behaviors are appropriate and inappropriate. Dishonesty may very well be one of the cases where the social norms that define acceptable behavior are not very clear, and the behavior of others […] can shape our ideas about what’s right and wrong.”

“Across all our experiments we’ve tested thousands of people, and from time to time, we did see aggressive cheaters who keep as much money as possible. In the matrix experiment, for example, we have never seen anyone claim to solve eighteen or nineteen out of the twenty matrices. But once in a while, a participant claimed to have solved all twenty matrices correctly. These are the people who, having made a cost-benefit analysis, decided to get away with as much money as possible. Fortunately, we didn’t encounter many of those folks […] they seemed to be the exception and not the rule”

A few final remarks related to that last quote. Ariely calls such behaviour ‘cheating’. I call it ‘doing the math’, ‘responding to incentives,’ or perhaps just ‘optimizing’. Incentives in these experiments were such that your payoff was unrelated to the factual accuracy of the numbers you reported, and depended only upon which numbers you actually reported. In such a setting, I’d just optimize. This is indicative, incidentally, I believe of a serious problem with these experiments more generally (and this is part of why I’m skeptical about more than a few of the findings). External validity may be quite low – the experiments may tell you very little about how people behave in the real world. I could tell the old story about the weird test subjects, the presence of significant Hawthorne effects, and so on and so forth – but you’ve all heard this stuff many times before if you’ve read along here. Anyway, from my behaviour in such experiments, if I were to partake in them, Ariely would infer that I was an ‘aggressive cheater’, one of the least trustworthy individuals of the people involved. Maybe I actually am that untrustworthy, maybe the results do have external validity. But if so, I should very much hope that Ariely at the very least would be considered just as dishonest as me in these experiments. I’d never pretend to be a cripple to skip the line in the airport, and I find such behaviour morally questionable at best.

September 10, 2013 Posted by | Books, Psychology | Leave a comment

(Part of…) why I’m single

How I spent my Saturday evening:

September 7, 2013 Posted by | Lectures, Medicine, Microbiology, Neurology, Personal | 2 Comments

Some physics videos

I’ve posted a few already, but these guys have put up a lot of good stuff:

(Of course I agree with Bowley’s observation that what you’re getting in a video like this is a garbled version – without understanding the math you won’t truly understand this stuff. But I still thought it was an interesting video.)

September 7, 2013 Posted by | Physics | Leave a comment


i. More U.S. Men Are Living Alone:

“The share of one-person households in the U.S. maintained by men ages 15 to 64 rose to 34% in 2012, up from 23% in 1970, according to a Census report on the status of families released Tuesday. For women of the same age, this figure actually dropped slightly, to 30% in 2012 from 31% in 1970.

The findings may reflect, in part, the sharp increase in divorce rates in the U.S. throughout the 1970s, Census said. The dominant living arrangement for children following their parents’ divorce is custody by mothers.”

I would have preferred to read the actual Census report and I did go have a look for it; but when I click the pdf link to the report in question at the census site all I get is an error message (link) – they seem to have put up a corrupt link. Annoying. Here are some related Danish numbers which I blogged a while ago. Although the 2012 report doesn’t seem to be available, there’s a lot of 2009-2011 data on related matters here. I messed around a little with that data – below some stuff from that source:

Naturally there’s a big gender disparity; at the age range of 24-29, 89.1% of males have never married whereas only 80,7% of the females have never married. For people in the 25-29 year age range 64% of males and 50,1% of females have never married. You’d expect the numbers to converge somewhat ‘over time’ (/as people get older) and they do, but not until we reach the age group of 55-64 year olds do the proportion of females who have never married surpass the proportion of males who have not (and these numbers are quite small – less than 9% have never married at that age, both when looking at males and females).

Higher earnings seem to confer an advantage when it comes to minimizing the risk of never getting married, which is of course a big surprise. For example, of the 45-49 year old people with a reported income of $25,000 to $39,999 17,6% of them have never married, whereas the corresponding number for people with an income of $40,000-75,000 is 11,5%. For people with incomes in the $75,000-$100,000 range the number is 5.5%, and incidentally the number of 45-49 year olds with incomes above $100k who’ve never married is also 5,5%. The relationship is not perfectly linear, but it’s clear that people with higher earnings have a higher likelihood of getting married. Incidentally almost a third of people in that age range who reported annual earnings less than $5000 have never married (29.2%).

The numbers above are from the first third of the first document. There’s a lot of data available here if you’re curious.

ii. Global Reality of Type 1 Diabetes Care in 2013. Not much to see here – here’s why I bookmarked it:

“from a global perspective, the most common cause of death for a child with type 1 diabetes is lack of access to insulin (2). Yet, this is not just a problem for low-income countries, with one recent study in the U.S. noting that discontinuation of insulin therapy represents the leading precipitating cause of diabetic ketoacidosis (3). Indeed, lack of insulin explained 68% of such episodes in people living in an inner-city setting, with approximately one-third of people reporting a lack of financial resources to buy insulin and eking out their insulin supplies.”

We’re talking about the United States of America, a very rich country – and in fact the country in the world with the highest health care expenditures. And still you have type 1 diabetics who go into ketoacidosis because they can’t afford their drugs. That’s messed up. Note that low medical subsidies to type 1s may not necessarily be cost saving at a systemic level as hospital admissions are very expensive; based on the average estimates at the link and these length of stay estimates, a back of the envelope estimate of the average cost of a DKA-related hospital admission would be $5.500. This estimate is probably too low as this study (which I may blog in more detail later) estimated non-compliance-related DKA-admissions to cost on average roughly $7.500 (and the non-compliance admissions were actually significantly cheaper than the other admissions on a per-case basis). To put this estimate into perspective, the mean annual cost of intensive diabetes care per diabetic patient in the U.S. is $4,000 (same link).

iii. Related to i., but I figured it deserved to be linked to separately: A theory of marriage, by Gary Becker.

iv. Some maps illustrating racial segregation patterns in the US. Don’t miss the sixth map of Detroit. The one of Saint Louis is also…

v. I haven’t used it much yet, so I don’t really know if it’s any good – but it looks interesting and I’ve missed such a resource. I sometimes feel a bit guilty about not working harder on improving my vocabulary, especially on account of the fact that I’ve basically ended up only speaking two languages – I used to speak French reasonably well, but that’s many years ago and at this point I’d rather spend time improving my English than spend a lot of effort on a third language which most likely will only be of very limited use to me.

vi. PLOS ONE: What Are You or Who Are You? The Emergence of Social Interaction between Dog and an Unidentified Moving Object (UMO). Here’s the abstract:

“Robots offer new possibilities for investigating animal social behaviour. This method enhances controllability and reproducibility of experimental techniques, and it allows also the experimental separation of the effects of bodily appearance (embodiment) and behaviour. In the present study we examined dogs’ interactive behaviour in a problem solving task (in which the dog has no access to the food) with three different social partners, two of which were robots and the third a human behaving in a robot-like manner. The Mechanical UMO (Unidentified Moving Object) and the Mechanical Human differed only in their embodiment, but showed similar behaviour toward the dog. In contrast, the Social UMO was interactive, showed contingent responsiveness and goal-directed behaviour and moved along varied routes. The dogs showed shorter looking and touching duration, but increased gaze alternation toward the Mechanical Human than to the Mechanical UMO. This suggests that dogs’ interactive behaviour may have been affected by previous experience with typical humans. We found that dogs also looked longer and showed more gaze alternations between the food and the Social UMO compared to the Mechanical UMO. These results suggest that dogs form expectations about an unfamiliar moving object within a short period of time and they recognise some social aspects of UMOs’ behaviour. This is the first evidence that interactive behaviour of a robot is important for evoking dogs’ social responsiveness.”

From the discussion:

“The aim of this study was to investigate whether dogs are able to differentiate agents on the basis of their behaviour and show social behaviours toward an UMO (Unidentified Moving Object) if the agent behaves appropriately in an interactive situation. In order to observe such interaction we modelled an experimental situation in which the dog is faced with inaccessible food. Miklósi et al [21] showed that in this case dogs increase their looking time at a human helper and show gaze alternation between the inaccessible food and the human. These observations have been replicated by Gaunet [23] and Horn et al [26], and the authors implicated that the dogs’ behaviour reflects communicative intentions. The present experiment showed that these behaviour features also emerge in the dogs while they are interacting with an UMO, moreover the onset of these behaviours is facilitated by the social features of the UMO: Dogs look longer and show more gaze alternation if the UMO carries eyes, shows variations in its path of movement, displays goal-directed behaviour and contingent reactivity (reacts to the looking action of the dog by retrieving the inaccessible food item).”

If you’re curious about how they actually did this stuff, don’t miss the neat video towards the end.

September 4, 2013 Posted by | Data, Demographics, Diabetes, marriage, Papers | Leave a comment

Back to work

“This text is the one of choice for micro courses in econ PhD programs. I (and several of my colleagues) almost quit the program because of this book (some in fact did). […] the econ was lost in this book, with math taking primary importance […] it is basically a math textbook with econ terminology sprinkled around”

“The authors present almost every idea in the most complicated way they could find.”

“This book […] is really an exercise in mathematical gymnastics.”

“Extremely technical and based around logical proofs of theory. You must learn to speak and read math as a language.”

As some people might already have inferred, I’ll be reading Mas-Colell this semester. Above quotes are from reviews of the book. A few more quotes:

“The problems in the text are among the most difficult I’ve ever encountered. They’re classified by difficulty A, B, & C, but even the A problems are often challenging and the C problems are practically impossible to understand–it’s no surprise that the solutions manual to this text is one of the most sought-after items in the econ grad student community.” (from this review).

“The exam difficulty will be about the same as the homework assignments.” (from the course description – all problems in the first assignment are taken directly from the book, and most of them are in the B category).

Given that the new semester has started, you can expect a lower posting frequency in the months to come. I assume some readers may have had difficulty keeping up with the posts I’ve written recently as I’ve covered a lot of stuff and blogged more than I ought to have, and if you’re one of those readers you may benefit from having a look at this summer’s archives instead of just hanging around getting annoyed at me for not updating more often in the time to come. In general I don’t cover current affairs stuff, so a lot of the stuff I’ve written in the past will be just as relevant in two months as it is now, and as mentioned I was quite productive during the last few months – e.g. I’ve read and blogged roughly 25 books since the start of June. As long as you don’t go back too far in the archives, you’ll be fine (I certainly wouldn’t recommend anyone reading stuff I wrote more than a few years ago).

September 2, 2013 Posted by | academia, Books, Economics, Personal | Leave a comment

The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (2)

Given the title of the post and some of the material covered, this post may by some be considered NSFW. I don’t know. Now you’re warned anyway.

I finished the book. My goodreads review reads as follows:

“Torn between two stars and three, I may still decide to give it two stars. First half was interesting (3,5 stars), second half was in my opinion very weak (1,5 stars). I was close to not finishing it. Very speculative, especially towards the end – it devolves into more or less pure storytelling.”

I’m quite disappointed. There’s good stuff in the second half, especially in the first part of the second half, but there’s a lot of crap too – chapter 9 was weak, and chapter 10 was bad too. Some of the stuff looked to me to be pretty much nothing but wild speculation supported by very little evidence, and bad evidence at that. Even worse, I get the distinct impression at least a few places that he seems to deliberately pick evidence that supports his views even though different evidence (and more relevant evidence) might very well lead to different conclusions – why would you use the vocabulary size of modern English speakers (60.000 words) to infer stuff about the language abilities and behaviours of our far ancestors, when it would presumably be much more informative to look at the vocabulary sizes of e.g. today’s Bushmen or Australian Aboriginals? And to which extent does it even make sense to make such inferences in the first place? On a different if related note he at one point spends a couple of pages to motivate why the reciprocity theory of courtship is obviously wrong, but what he’s actually arguing against is a straw-man that is very hard to take seriously and seems completely irrelevant to the validity of the model. He employs manipulative argumental strategies along the way more than once and when he does this it makes it hard for me not to jump to the conclusion that his arguments stink even though they may not actually do so – I don’t like it when I get the impression that someone is trying to manipulate me, and Miller comes off as occasionally quite manipulative to me in this book.

Anyway, some quotes from the last half as well as a few comments. I’ve mostly (but not only) quoted from the good stuff because I don’t want to spend a lot of time on the other stuff:

“When we see a human perceptual or cognitive ability that looks curiously sensitive to stimulation yet resistant to satisfaction, we should not assume that it is a poorly designed information processing system. It may be part of a system for sexual or social discrimination. […] Female orgasm seems poorly designed as a pair-bonding mechanism, but it is perfectly designed as a discriminatory system that separates the men from the boys.”

“It seems likely that male choice shaped breasts not to distinguish girls from young women, but to distinguish young women from older women. Here, the informative thing about breasts is the way they droop with the effects of age and gravity. There is a relatively narrow age window in which large breasts can appear pert before repeated cycles of pregnancy and breast-feeding causes them to sag. There were no bras or breast-lift operations in the Pleistocene. […] hominid males probably favoured younger women for their higher fertility. Any indicator of youth, such as large, pert breasts, would tend to be favoured by males. […] an attractiveness benefit in youth can often outweigh an unattractiveness cost in older age. This is why it can be in the interest of females to evolve youth indicators such as large breasts that tend to droop, fine skin that tends to wrinkle, and buttocks that tend to develop stretch marks. […] women with more symmetric breasts tend to be more fertile. […] The larger the breasts, the easier it is to notice asymmetries. […] The role of breasts as fitness indicators may help to explain why there is so much variation in breast size between women. […] fitness indicators do not tend to converge on a single size in a population. They maintain their variation indefinitely, due to the effects of genetic mutation and variation in condition.”

“Most evolutionary psychologists have viewed human morality as a question of altruism, and have tried to explain altruism as a side-effect of instincts for nepotism (kindness to those who may reciprocate). I think human morality is much more likely to be a direct result of sexual judgments today because our ancestors favored sexual partners who were kind, generous, helpful, and fair. We still have the same preferences. David Buss’s study of global sexual preferences found that ‘kindness’ was the single most important feature desired in a sexual partner by both men and women in every one of the 37 cultures he studied. It ranked above intelligence, above beauty, and above status.” (If not for the fact that he actually thinks this stuff is true, it’d be hilarious. Here’s a link. I’m pretty sure Buss’s study belongs in the “completely useless” category. This is just stupid.)

“Ecologists have long understood that the typical interaction between any two individuals or species is neither competition nor cooperation, but neutralism. Neutralism means apathy: the animals just ignore each other. If their paths threaten to cross, they get out of each other’s way. Anything else usually takes too much energy. Being nasty has costs, and being nice has costs, and animals evolve to avoid costs whenever possible. […] most of the violent competition happens within a species, because animals of the same species are competing for the same resources and the same mates. […] If we were typical animals, our attitudes to others would be dominated not by hate, exploitation, spite, competitiveness, or treachery, but by indifference. And so they are.”

“Verbal courtship can be viewed narrowly as face-to-face flirtation, or broadly as anything we say in public that might increase our social status or personal attractiveness in the eyes of potential mates. […] Verbal courtship in the broader sense explains why we compete to say interesting, relevant things in groups. Sexual choice permeates human social life, because anything that raises social status tends to improve mating prospects.” […] In cooperative communication, the receiver may be mildly skeptical about the information conveyed. In courtship, the receiver is extremely judgmental not only about the information, but about the signaller. When listening, we automatically evaluate whether what is being said makes sense, whether it is congruent with what we know and believe, whether it is novel and interesting, and whether we can draw intriguing inferences from it. But we also use all of these judgments to form an impression of the speaker’s intelligence, creativity, knowledge, status, and personality. We assess the information content of utterances not just to make inferences about the world, but to make attributions about the speaker.”

“People tend to socialize with friends and sexual partners who show roughly their own verbal ability level – their verbal compatibility has already determined which social relationships were formed. The majority of human conversation occurs between sexual partners and long-term friends. They have already chosen each other as mates or friends precisely because their first few conversations were mutually interesting, evoking mutual respect and attraction.”

“we present our lives in the best possible light. We mention our successes rather than our failures, impressive relatives rather than wastrels, dramatic trips more than solitary depressions, and palatable beliefs more than secret bigotries. Our life stories presents us as the heroes of the grand adventures that are our lives, rather than the Rosenkrantz and Guildenstern to someone else’s Hamlet. Nevertheless, because most people distort their life stories to more or less the same degree, they remain a valid basis for mate choice. Initially at least, our life stories will be compared not to the truth, but to the equally distorted life stories of our sexual competitors.” (No, honest signalling in this framework simply doesn’t make any sense. Lying isn’t optional.)

“How should we interpret the female superiority on language comprehension tests [“women comprehend more words on average, and this sex difference accounts for almost 5 percent of the individual variation in vocabulary size.”], given the greater male motivation to produce public verbal displays? The latter has not been so well quantified yet, but it is still obvious. Men write more books. Men give more lectures. Men ask more questions after lectures. Men dominate mixed-sex committee discussions. […] men can’t be quiet because that would give other men a chance to show off verbally. Men often bully women into silence, but this is usually to make room for their own display. ”

“Human courtship, like courtship in other animals, has a typical time-course. Courtship effort is low when first assessing a sexual prospect, increases rapidly if the prospect reciprocates one’s interest, peaks when the prospect is deciding whether to copulate, and declines once a long-term relationship is established.”

“People act differently when they’re in love with different people. We tend to match our expressed interests and preferences to those of a desired individual. […] In courtship, we work our way into roles that we think will prove attractive. […] Acting is not the prerogative of a few highly strung professionals, but a human birthright, automatically activated whenever we fall in love. In courtship, all the world became a stage, and all the proto-humans merely players.” (link in case you didn’t get the reference)

September 1, 2013 Posted by | Anthropology, Biology, Books, Ecology, Evolutionary biology, Language, Psychology | 14 Comments