On the origins of birds: the sequence of character acquisition in the evolution of avian flight

Assessment of competing theories for the evolution of avian flight is problematic, and tends to rest too heavily on reconstruction of the mode of life of one or a few specimens representing still fewer species. A more powerful method is to compare the sequence of character acquisition predicted by the various theories with the empirical sequence provided by cladistic phylogeny. Arboreal and cursorial theories incorrectly predict the sequence of character acquisition for several key features of avian evolution. We propose an alternative ''pouncing proavis'' model for the evolution of flight. As well as being both biologically and evolutionarily plausible, the pouncing proavis model correctly predicts the evolutionary sequence of all five key features marking the evolution of birds.     

Ever Try Teaching a Dog To Read? Implicit Theories of Reading Ability

ABSTRACT

When explaining academic outcomes in specific content areas, people reveal their implicit theories of academic ability. Those who hold an entity theory generally attribute differences in achievement to stable, uncontrollable factors. In contrast, those who hold an incremental theory take into account controllable psychological or environmental variables. Implicit theories affect motivation and are expected to crystallize by about fourth grade. This research examined changes in southwest suburban third graders' implicit theories of reading ability for self, others, and other species in a quasi-experimental, crossover design employing entity and incremental treatments. Seventy-one third-graders completed a 16-week reading program teaching a dog tasks that supported and challenged entity theories of what dogs can do. A therapy dog acted as our confederate because reading to dogs has been shown to improve children's reading skills, but not necessarily change their beliefs about reading ability, because beliefs are resistant to change and require personal experiences that encourage revision. Repeated measures analysis of co-variance (ANCOVA) revealed a significant change in students' theories of reading ability (F_{(1, 59)} = 60.61, p < 0.001). Students' incremental scores increased following the entity condition (F_{(1, 64)} = 1.165, p < 0.02); their entity scores decreased following both conditions (F_{(1, 59)} = 21.90, p < 0.001). Students' implicit theories of reading ability for self, other, and other species did not differ; a significant effect of belief in dogs' reading ability (F_{(1, 59)} = 29.04 p < 0.001) was observed. Implications for increasing children's reading motivation and achievement are discussed.     

CMA-cosponsored conference raises many questions about future of regionalized health care.

Is regionalization better because it''s cheaper? Or because it provides better outcomes? Or simply because it''s different from whatever went before? Those were some of the questions asked during a recent conference cosponsored by the CMA and Queen''s University. With each successive speaker, says Charlotte Gray, the message became clearer: there are more muddled theories behind the trend and more pitfalls ahead than planners ever expected when they embarked on the exercise to decentralize health care in Canada and elsewhere.     

The role of pattern recognition in creative problem solving: A case study in search of new mathematics for biology

Rosen classified sciences into two categories: formalizable and unformalizable. Whereas formalizable sciences expressed in terms of mathematical theories were highly valued by Rutherford, Hutchins pointed out that unformalizable parts of soft sciences are of genuine interest and importance. Attempts to build mathematical theories for biology in the past century was met with modest and sporadic successes, and only in simple systems. In this article, a qualitative model of humans' high creativity is presented as a starting point to consider whether the gap between soft and hard sciences is bridgeable. Simonton's chance-configuration theory, which mimics the process of evolution, was modified and improved. By treating problem solving as a process of pattern recognition, the known dichotomy of visual thinking vs. verbal thinking can be recast in terms of analog pattern recognition (non-algorithmic process) and digital pattern recognition (algorithmic process), respectively. Additional concepts commonly encountered in computer science, operations research and artificial intelligence were also invoked: heuristic searching, parallel and sequential processing. The refurbished chance-configuration model is now capable of explaining several long-standing puzzles in human cognition: a) why novel discoveries often came without prior warning, b) why some creators had no ideas about the source of inspiration even after the fact, c) why some creators were consistently luckier than others, and, last but not least, d) why it was so difficult to explain what intuition, inspiration, insight, hunch, serendipity, etc. are all about. The predictive power of the present model was tested by means of resolving Zeno's paradox of Achilles and the Tortoise after one deliberately invoked visual thinking. Additional evidence of its predictive power must await future large-scale field studies. The analysis was further generalized to constructions of scientific theories in general. This approach is in line with Campbell's evolutionary epistemology. Instead of treating science as immutable Natural Laws, which already existed and which were just waiting to be discovered, scientific theories are regarded as humans' mental constructs, which must be invented to reconcile with observed natural phenomena. In this way, the pursuit of science is shifted from diligent and systematic (or random) searching for existing Natural Laws to firing up humans' imagination to comprehend Nature's behavioral pattern. The insights gained in understanding human creativity indicated that new mathematics that is capable of handling effectively parallel processing and human subjectivity is sorely needed. The past classification of formalizability vs. non-formalizability was made in reference to contemporary mathematics. Rosen's conclusion did not preclude future inventions of new biology-friendly mathematics.     

Nucleosomes,transcription, and probability

Speaking of current measurements on single ion channel molecules, David Colquhoun wrote in 2006, “Individual molecules behave randomly, so suddenly we had to learn how to deal with stochastic processes.” Here I describe theoretical efforts to understand recent experimental observations on the chromatin structure of single gene molecules, a molecular biologist''s path toward probabilistic theories.     

Research on dead human bodies: African perspectives on moral status

A useful concept that can be invoked to resolve complex bioethical issues is that of moral status (or, human dignity). In this article, we apply this concept to dead human bodies in order to support our view that research on such bodies is permissible. Instead of drawing from salient Western theories of human dignity that account for it by appeals to autonomy or rationality, we will base our investigation on emerging conceptions in African theories of moral status as articulated by Thaddeus Metz and Munamato Chemhuru. Our conclusion is that neither of these theories of moral status, one secular, and the other religious, can accommodate the intuition that we have direct duties of respect towards such bodies because, in relation to Metz's conception, they lack the capacity to enter into social relationships while on Chemhuru's conception, dead bodies appear not to have any meaningful purpose within the hierarchy that captures the ontological systems that determine such status. Consequently, we argue that our analysis provides support for the use of unclaimed cadavers in training and research in medical institutions.     

Family Socialization Practices and Their Effects on the Internalization of Educational Values for Asian and White American Adolescents

Based on the theories of internalization and the self, this article examines effective family socialization practices of Asian and White Americans. The results indicated that parental support for autonomy and adolescents' perceived competence while studying favorably affected Asian Americans' internalization of their cultural values relevant to education and academic success. In contrast, for White Americans, these internalization factors did not have a substantial effect on adolescents' school performance. Moreover, for Asian Americans, parents' attitudes had stronger effects on adolescents' school performance in comparison to White American adolescents, whose teacher-awarded grades were attributed to their own academic aspirations. Differences in family socialization practices between Asian and White Americans are discussed within a context of underlying cultural frameworks that promote adolescents' school performance.     

Inner Speech And The Processes of Grammatical Generation of Utterances

The present article contains no ultimate truths. As indicated in the title, the author's aim is to present, on the basis of presently available data, a few hypotheses concerning socalled "inner speech" in order to provide a foundation for experimental investigations. These hypotheses have as their premise the general conception of processes of speech generation that is current in contemporary Soviet psychology, in particular, in L. S. Vygotsky's school, as well as in another school of Soviet physiology of higher nervous activity associated with the name of N. A. Bernshteyn. However, these hypotheses are not, in principle, incompatible with certain other theories of verbal activity (verbal behavior); indeed, as will be evident later, they are partially based on material accumulated with the aid of these theories.     

Gendering unemployment in postsocialist Germany: ‘what I do is work,even if it's not paid’

This article uses feminist theories of the family to examine women's unemployment in the early years of German postsocialism. It is based on qualitative fieldwork, including 80 in-depth interviews, conducted in three cities in the formerly socialist region of Germany. In this article, three cases of couples coping with a wife's unemployment are analyzed in terms of micro-processes of negotiating work-family balance, redefining employment and domesticity, and reconstructing gendered identities. The central argument is that a couple's stance on emerging market institutions shaped how they re-negotiated their gender division of labor during postsocialism.     

Negative refraction angular characterization in one-dimensional photonic crystals

Background

Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here we experimentally characterize negative refraction in a one dimensional photonic crystal structure; near the low frequency edge of the fourth photonic bandgap. We compare the experimental results with current theory and a theory based on the group velocity developed here. We also analytically derived the negative refraction correctness condition that gives the angular region where negative refraction occurs.

Methodology/Principal Findings

By using standard photonic techniques we experimentally determined the relationship between incidence and negative refraction angles and found the negative refraction range by applying the correctness condition. In order to compare both theories with experimental results an output refraction correction was utilized. The correction uses Snell''s law and an effective refractive index based on two effective dielectric constants. We found good agreement between experiment and both theories in the negative refraction zone.

Conclusions/Significance

Since both theories and the experimental observations agreed well in the negative refraction region, we can use both negative refraction theories plus the output correction to predict negative refraction angles. This can be very useful from a practical point of view for space filtering applications such as a photonic demultiplexer or for sensing applications.     

Women's Representation in 60 Occupations from 1972 to 2010: More Women in High-Status Jobs,Few Women in Things-Oriented Jobs

To explore factors associated with occupational sex segregation in the United States over the past four decades, we analyzed U.S. Bureau of Labor Statistics data for the percent of women employed in 60 varied occupations from 1972 to 2010. Occupations were assessed on status, people-things orientation, and data-ideas orientation. Multilevel linear modeling (MLM) analyses showed that women increasingly entered high-status occupations from 1972 to 2010, but women''s participation in things-oriented occupations (e.g., STEM fields and mechanical and construction trades) remained low and relatively stable. Occupations'' data-ideas orientation was not consistently related to sex segregation. Because of women''s increased participation in high-status occupations, occupational status became an increasingly weak predictor of women''s participation rates in occupations, whereas occupations'' people-things orientation became an increasingly strong predictor over time. These findings are discussed in relation to theories of occupational sex segregation and social policies to reduce occupational sex segregation.     

The exotic and the mundane

The HIV/AIDS epidemic in Haiti has often been referred to as a “mystery,” and “striking similarities” between patterns of disease in Haiti and in sub-Saharan Africa are often underlined. The occurrence of AIDS in Haitians has also led to the postulation of a number of theories positing a Haitian origin for AIDS and linking the syndrome in Haitians to voodoo. A review of the epidemiological data gathered and published in the early years of the pandemic suggests that these “exotic” theories are not necessary to explain the Haitian epidemic, which is clearly linked not to Africa but to the United States. Patterns of risk identified among many of the first Haitians with AIDS are similar to risk factors identified in North America and Europe (same-sex contact with an HIV-infected individual and blood transfusion). The Haitian epidemicsubsequently came to resemble patterns seen in sub-Saharan Africa, where AIDS is predominantly a heterosexually transmitted disease. Similarly shifting patterns are described for several other Caribbean nations, underlining the importance of a historical analysis of the Caribbean pandemic as well as the necessity to link analysis of local epidemiology of AIDS/HIV to larger considerations of political economy.     

Constructing difference and sameness: the politics of assimilation in London's Arab communities

Contemporary migration has spurred reconsideration of the theoretical concepts used to explain immigrant-host society relationships. Traditional conceptions of assimilation have been an important topic of debate. Some urban sociologists question whether timeworn assimilation models 'fit' contemporary circumstances. Others challenge assimilation theories on a more fundamental level, abandoning notions of 'group adaptation' and focusing instead on social difference and cultural identity. Thus far, there has been very little dialogue between different theoretical perspectives. I attempt to bridge this gap by conceptualizing assimilation as observable, material processes of accommodation of and conformity to dominant norms. Assimilation, in this respect, is profoundly political rather than ecological or 'natural', and is relevant across geographical and historical contexts. Drawing on interviews with Arab immigrants in London, I shall illustrate the ways in which the construction of sameness (as well as difference) is central to immigrant experiences.     

The Development of Play in Preschoolers

The motives of play activity constitute a key question. It is no accident that views on play diverge most conspicuously with regard to the the stimuli leading to play. Theories of satisfaction, pleasure, internal primary drives and self-affirmation—all "in-depth theories"—are essentially theories of the motivating forces that give rise to play. The principal flaw in these conceptions is how they construe the motivating forces of play: they are situated in the subject, in the child and in the child's experiences. These theories discount the fact that these experiences are but secondary to an activity, i.e., they are symptomatic in that they indicate the activity is indeed taking place, but they tell us nothing about the real, objective, stimuli of the activity.     

The semantic approach to evolutionary theory

Paul Thompson, John Beatty, and Elisabeth Lloyd argue that attempts to resolve certain conceptual issues within evolutionary biology have failed because of a general adherence to the received view of scientific theories. They maintain that such issues can be clarified and resolved when one adopts a semantic approach to theories. In this paper, I argue that such conceptual issues are just as problematic on a semantic approach. Such issues arise from the complexity involved in providing formal accounts of theoretical laws and scientific explanations. That complexity is due to empirical and pragmatic considerations, not one's adherence to a particular formal approach to theories. This analysis raises a broader question. How can any formal account properly represent the complex nature of empirical phenomena?     

Dynamic actin interaction of crossbridges: A general principle and its implications for crossbridge action in muscle

The oar-like crossbridge cycle, developed up to the mid-1970's, was shown to be inconsistent with more recent biochemical results. In crossbridge theories developed on the basis of the more recent kinetic schemes of the actomyosin ATPase in solution (Eisenberg and co-workers), however, the key elements proposed by Huxley (1957) were retained, one of which is the assumption that detachment of a force-generating crossbridge can only occur via completion of the ATPase cycle (release of ADP and rebinding of ATP). Furthermore, in these theories regulation is assumed to act by blocking/unblocking of a step subsequent to crossbridge attachment (e.g., P_i-release step). Both concepts, however, were recently shown to be in conflict with studies on skinned muscle fibers (still low ATPase activity at high-speed isotonic shortening, regulation acts via turnover kinetics and not recruitment (39)). By incorporation of the observed reversible actin interaction of crossbridges in all states, including the force-generating states, a working hypothesis can be developed (Fig. 5) which can account for the isotonic data. A mechanism by which such a scheme can also account for regulation via turnover kinetics was previously discussed (39).     

Knowledge-based vision and simple visual machines.

The vast majority of work in machine vision emphasizes the representation of perceived objects and events: it is these internal representations that incorporate the ''knowledge'' in knowledge-based vision or form the ''models'' in model-based vision. In this paper, we discuss simple machine vision systems developed by artificial evolution rather than traditional engineering design techniques, and note that the task of identifying internal representations within such systems is made difficult by the lack of an operational definition of representation at the causal mechanistic level. Consequently, we question the nature and indeed the existence of representations posited to be used within natural vision systems (i.e. animals). We conclude that representations argued for on a priori grounds by external observers of a particular vision system may well be illusory, and are at best place-holders for yet-to-be-identified causal mechanistic interactions. That is, applying the knowledge-based vision approach in the understanding of evolved systems (machines or animals) may well lead to theories and models that are internally consistent, computationally plausible, and entirely wrong.