Somites are transient structures which represent the most overt segmental feature of the vertebrate embryo. The strict temporal regulation of somitogenesis is of critical developmental importance since many segmental structures adopt a periodicity based on that of the somites. Until recently, the mechanisms underlying the periodicity of somitogenesis were largely unknown. Based on the oscillations of c-hairy1 and lunatic fringe RNA, we now have evidence for an intrinsic segmentation clock in presomitic cells. Translation of this temporal periodicity into a spatial (...) periodicity, through somite formation, requires Notch signaling. While the Hox genes are certainly involved, it remains unknown how the metameric vertebrate axis becomes regionalized along the antero–posterior (AP) dimension into the occipital, cervical, thoracic, lumbar, and sacral domains. We discuss the implications of cell division as a clock mechanism underlying the regionalization of somites and their derivatives along the AP axis. Possible links between the segmentation clock and axial regionalization are also discussed. (shrink)

Given the widening gap between the number of individuals on transplant waiting lists and the availability of donated organs, as well as the recent plateau in donations based on neurological criteria, there has been a growing interest in expanding donation after circulatory determination of death. While the prevalence of this form of organ donation continues to increase, many thorny ethical issues remain, often creating moral distress in both clinicians and families. In this article, we address one of these issues, namely, (...) the challenges surrounding patient and surrogate informed consent for donation after circulatory determination of death. First we discuss several general concerns regarding consent related to this form of organ donation, and then we address additional issues that are unique to three different patient categories: adult patients with medical decision-making capacity or potential capacity, adult patients who lack capacity, and pediatric patients. (shrink)

Chow's monograph exhibits four prototypical symptoms of psychology's enduring scientific crisis: it equates empirical science with statistical analysis; it settles for qualitative rather than quantitative theories; it ignores the role of ecological validity in the generalizability of theories; and it puts rigid adherence to arbitrary but documentable rules over critical thinking about the meaning of results.

: This article describes a psychological test of Hull's (1988) theory of science as an evolutionary process by seeing if it can account for how scientists sometimes remember and cite the scientific literature. The conceptual adequacy of Hull's theory was evaluated by comparing it to Bartlett's (1932) seminal theory of human remembering. Bartlett found that remembering is an active, reconstructive process driven by a schema that biases recall in the direction of proto- typicality and personal involvement. This account supports Hull's (...) theory of science because it shows that the characteristics of reconstructive remembering are consistent with the generic properties of an evolutionary process. The empirical adequacy of Hull's theory was evaluated by comparing the predictions made from this evolutionary viewpoint against evidence from the history of science. Six cases studies of well-known psychological experiments that had been subject to repeated miscitation errors were collected and reviewed. All six case studies revealed a systematic pattern of distortions that is consistent with the schema-induced biases of reconstructive remembering. These findings support Hull's claim that science is an evolutionary process with scientists as interactors, scientific beliefs as replicators, and schemata as means for that replication. (shrink)

Abstract(1) The miscitations of seminal experiments in the base rate literature adds to the existing database of systematic miscitations of wellknown psychological experiments. These miscitations may be caused by a process of reconstructive remembering. (2) Representative design should be the methodological core of Koehler's call for ecologically valid research. This approach can benefit both basic and applied research.

Im Jahre 1998 verblüfften Andy Clark und David Chalmers die philosophische Gemeinschaft mit der so genannten These des erweiterten Geistes, die im Kern besagt, dass kognitive Systeme nicht-biologische Komponenten enthalten können und sich damit über die Grenzen biologischer Organismen hinaus erstrecken können. Die These wird seitdem nicht nur von Philosophen, sondern auch von Kognitions- und Neurowissenschaftlern intensiv und kontrovers diskutiert. In den Beiträgen, die in dem vorliegenden ersten deutschsprachigen Band zur These des erweiterten Geistes versammelt sind, werden u.a. die folgenden (...) Fragen behandelt: Was soll es heißen, dass der Geist nicht (nur) im Kopf ist? In welchem Sinne könnte er erweitert sein, und welche Möglichkeiten der Erweiterung gibt es? Welche Zusammenhänge bestehen zwischen Geist und Kognition sowie zwischen Kopplung und Konstitution? Was genau besagt der von Clark und Chalmers vorgebrachte aktive Externalismus? Welche Bedeutung hat die These des erweiterten Geistes für repräsentationalistische und für funktionalistische Theorien des Geistes sowie für Theorien kollektiver Intentionalität und sozialer Kognition? Welche Anwendungen der These könnte es geben? (shrink)

Anthony Giddens’ theory of structuration is a theory of social action, which claims that society should be understood in terms of action and structure; a duality rather than two separate entities. This paper introduces some of the central characteristics of structuration theory, presenting a conceptual framework that helps to explore how people produce the systems and structures that shape their practice. By understanding how people produce and reproduce structures, then there is the potential for changing them. Criticisms that have been (...) raised about the theory are introduced, followed by examples of how the theory might be useful to nursing research. Structuration theory can be employed to explore how nurses produce, reproduce, and transform nursing practice through social interaction across time and space. (shrink)

Postural reflexes are essential for locomotion and postural stability, and may play an important role in the etiology of chronic back pain. It has recently been theoretically predicted, and with the help of unilateral perturbations of the trunk experimentally confirmed that the sensorimotor control must lower the reflex amplitude for increasing reflex delays to maintain spinal stability. The underlying neuromuscular mechanism for the compensation of postural perturbations, however, is not yet fully understood. In this study, we applied unilateral and bilateral (...) sudden external perturbations to the trunk of healthy subjects and measured the muscular activity and the movement onset of the trunk. We found that the onset of the trunk muscle activity is prior to, or coincident with, the onset of the trunk movement. Additionally, the results of our experiments imply that the muscular response mechanism integrates distant sensory information from both sides of the body. These findings rule out a simple monosynaptic stretch reflex in favor of a more complex polysynaptic postural reflex mechanism to compensate postural perturbations. Moreover, the previously predicted negative correlation between reflex delay and reflex gain was also confirmed for bilateral perturbations. (shrink)

The language $L_A(\Finv)$ is formed by adding the quantifier $\Finv x$ , "few x", to the infinitary logic L A on an admissible set A. A complete axiomatization is obtained for models whose universe is the set of ordinals of A and where $\Finv x$ is interpreted as there exist A-finitely many x. For well-behaved A, every consistent sentence has a model with an A-recursive diagram. A principal tool is forcing for $L_A(\Finv)$.

The language $L_A$ is formed by adding the quantifier $\Finv x$ , "few x", to the infinitary logic L A on an admissible set A. A complete axiomatization is obtained for models whose universe is the set of ordinals of A and where $\Finv x$ is interpreted as there exist A-finitely many x. For well-behaved A, every consistent sentence has a model with an A-recursive diagram. A principal tool is forcing for $L_A$.

In this study, we elaborate connections among gender, structure, and practice to suggest how social structural relations shape social sexual practice and, in the process, reshape gender relations. Using survey data from a study of a community mobilization intervention, we investigate the connection between institutional arrangements and condom use practice in sexual encounters with commercial clients and intimate partners among 410 women engaged in sex trade in a semiurban town in southern India. Multinomial logistic regression analysis uncovers the effects of (...) 16 measures of gendered structural relations in three contexts—livelihood resources, household circumstances, and community mobilization intervention priorities. We compare women who practice either consistent or inconsistent condom use with both clients and partners with a reference group of women who practice consistent condom use with clients but not with partners. Results reveal the importance of household and community relations for consistent safer sex practice over and above the organization of sex trade. Our analysis advances gender theory in two interrelated ways: We contribute to gender theorizing in the implementation of health interventions, and to gender change more generally by thinking through possibilities emerging from recursive influences between reordered institutional configurations and altered expectations in interaction. (shrink)

During somitogenesis an oscillatory mechanism termed the “segmentation” clock generates periodic waves of gene expression, which translate into the periodic spatial pattern manifest as somites. The dynamic expression of the clock genes shares the same periodicity as somitogenesis. Notch signaling is believed to play a role in the segmentation clock mechanism. The paper by Hirata et al.(1) identifies a biological clock in cultured cells that is dependent upon the Notch target gene Hes1, and which shows a periodicity similar to that (...) of the segmentation clock. This finding opens the possibility that the same oscillator mechanism might also operate in other tissues or cell types. BioEssays 25:200–203, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

During somitogenesis an oscillatory mechanism termed the “segmentation” clock generates periodic waves of gene expression, which translate into the periodic spatial pattern manifest as somites. The dynamic expression of the clock genes shares the same periodicity as somitogenesis. Notch signaling is believed to play a role in the segmentation clock mechanism. The paper by Hirata et al.(1) identifies a biological clock in cultured cells that is dependent upon the Notch target gene Hes1, and which shows a periodicity similar to that (...) of the segmentation clock. This finding opens the possibility that the same oscillator mechanism might also operate in other tissues or cell types. BioEssays 25:200–203, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Negative campaigning is a central component of political campaigns in the United States. Yet, until now, most evidence has suggested that negative campaigning has little effect on voters. How can we reconcile the findings of a plethora of empirical studies with the methods of political elites? This book cuts through to the central issue: how such advertising influences voters' attitudes and their actions during campaigns. Focusing on U.S. senatorial campaigns, Kim Fridkin and Patrick Kenney draw from surveys, experiments, facial expression (...) emotion tests, content analyses, and focus groups. They develop the "tolerance and tactics theory of negativity" and demonstrate the divergent effects of tone and content on voter outcomes. Using their new framework, they find that harsh messages seen as relevant to the opponent's ability to govern are indeed likely to be noticed and acted upon. (shrink)

In this paper we introduce the concept of d-fuzzy function which generalizes the concept of fuzzy subalgebra to a much larger class of functions in a natural way. In addition we discuss a method of fuzzification of a wide class of algebraic systems onto [0, 1] along with some consequences.

Are risk behaviours in adolescence differentiated according to same-sex vs opposite-sex interest? For all respondents a five-point scale of interest in each sex used information from both of the first two in-home waves of the National Longitudinal Study of Adolescent Health (Add Health). Logistic regression predicted the probability of experiencing each risk behaviour from the same-sex and opposite-sex interest scores. Same-sex interests have more effect on emotional risk, and opposite-sex interests have more effect on substance use. Nevertheless, all risk variables (...) except boys’ depression are responsive to both same-sex and opposite-sex interest. The same-sex interest component of risk is attributed to the emotional strain of living with an anomalous sex interest in a heterosexual society. (shrink)

While stigmatisation is universal, stigma research in low- and middle-income countries (LMIC) is limited. LMIC stigma research predominantly concerns health-related stigma, primarily regarding HIV/AIDS or mental illness from an adult perspective. While there are commonalities in stigmatisation, there are also contextual differences. The aim of this study in DR Congo (DRC), as a formative part in the development of a common stigma reduction intervention, was to gain insight into the commonalities and differences of stigma drivers (triggers of stigmatisation), facilitators (factors (...) positively or negatively influencing stigmatisation), and manifestations (practices and experiences of stigmatisation) with regard to three populations: unmarried mothers, children formerly associated with armed forces and groups (CAAFAG), and an indigenous population. Group exercises, in which participants reacted to statements and substantiated their reactions, were held with the ‘general population’ (15 exercises, n = 70) and ‘populations experiencing stigma’ (10 exercises, n = 48). Data was transcribed and translated, and coded in Nvivo12. We conducted framework analysis. There were two drivers mentioned across the three populations: perceived danger was the most prominent driver, followed by perceived low value of the population experiencing stigma. There were five shared facilitators, with livelihood and personal benefit the most comparable across the populations. Connection to family or leaders received mixed reactions. If unmarried mothers and CAAFAG were perceived to have taken advice from the general population and changed their stereotyped behaviour this also featured as a facilitator. Stigma manifested itself for the three populations at family, community, leaders and services level, with participation restrictions, differential treatment, anticipated stigma and feelings of scapegoating. Stereotyping was common, with different stereotypes regarding the three populations. Although stigmatisation was persistent, positive interactions between the general population and populations experiencing stigma were shared as well. This study demonstrated utility of a health-related stigma and discrimination framework and a participatory exercise for understanding non-health related stigmatisation. Results are consistent with other studies regarding these populations in other contexts. This study identified commonalities between drivers, facilitators and manifestations—albeit with population-specific factors. Contextual information seems helpful in proposing strategy components for stigma reduction. (shrink)

Editorial for ‘One Christ—Many Witnesses: Marking the Completion of the Regnum Edinburgh Centenary Series’, a special issue to celebrate the Regnum Edinburgh Centenary Issue.

In many traditional, small-scale societies, death and other misfortunes are commonly explained as a result of others’ malign occult agency. Here, we call this family of epistemic tendencies “the agential view of misfortune.” After reviewing several ethnographic case studies that illustrate this view, we argue that its origins and stability are puzzling from an evolutionary perspective. Not only is the agential view of misfortune false; it imposes costs on individuals and social groups that seem to far outweigh whatever benefits the (...) view might provide. We thus doubt that the agential view of misfortune is explainable in terms of adaptive effects. However, neither does it seem readily explainable as a consequence of belief formation strategies that are on the whole adaptive (as is plausibly the case for certain other of our false beliefs, including some that are costly). Accordingly, we contend that the commonness of the agential view of misfortune demands a special evolutionary explanation of some kind. We provide a partial explanation of this phenomenon by highlighting the adaptive benefits that often flow to occult specialists in environments where the agential view of misfortune is entrenched. What this does not explain, however, is the general lack of resistance we observe in response to occultists’ exploitative behaviours over (cultural) evolutionary timescales. We conclude by canvassing a few possible explanations for this puzzling lack of resistance, and while we commit ourselves to none, we do find one option more promising than the others. (shrink)

Over the past 20 years or so, a small but growing literature has emerged with the aim of modeling agents who are unaware of certain things. In this paper we compare two different approaches to modeling unawareness: the object-based approach of Board and Chung (Object-based unawareness: theory and applications. University of Minnesota, Mimeo, 2008) and the subjective-state-space approach of Heifetz et al. (J Econ Theory 130: 78-94,2006). In particular, we show that subjectivestate-space models (henceforth HMS structures) can be embedded within (...) object-based models (henceforth OBU structures), demonstrating that the latter are at least as expressive. As long as certain restrictions are imposed on the form of the OBU structure, the embedding can also go the other way. A generalization of HMS structures (relaxing the partitional properties of knowledge) gives us a full converse. (shrink)

The controversy around the accommodation of conscientious objections in medicine persists, especially for such contentious services as abortions. COs are typically considered in their negativ...

Written in an engaging narrative style these philosophical investigations undermine racist hierarchies along with false natualistic conceptions of the meanings of race and universalistic understandings of gender, by considering whiteness as it shapes and is infused by gender, class, sexuality, and culture. Central to this project are questions about how it is that culture and the state create such a wide range of different people who understand themselves as white. The essays collected here discuss how one learns to be a (...) good white Southern woman, what it means to pass as white, and whether there really is a dilemma that accompanies white privilege. (shrink)

The papers in this issue are based on presentations by the authors at the 163nd National Meeting of the American Association for the Advancement of Science, Seattle, Washington, 13–18 February 1997 in the session entitled Damned If You Do, Damned If You Don’t: What the Scientific Community Can Do about Whistleblowing organized by Stephanie J. Bird and Diane Hoffman-Kim. The papers have been modified following double blind peer review.

The spatial dynamics of the optical emission from an array of 50 times 50 individual microcavity plasma devices is investigated. The array is operated in argon and argon-neon mixtures close to atmospheric pressure with an ac voltage. The optical emission is analysed with phase and space resolution. It has been found that the emission is not continuous over the entire ac period, but occurs once per half period. Each of the observed emission phases shows a self-pulsing of the discharge, with (...) several bursts of emission of fixed width and repetition rate. The number of emission bursts depends on applied voltage and frequency. Spatially resolved measurements prove that the emission bursts are formed by overlapping emission pulses from single discharge cavities. Intensity differences between positive and negative half-wave can be interpreted through spatially resolved measurements of single discharge cavities. (shrink)