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)

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)

The scope of Philosophy in Multiple Voices provides the reader with eight philosophical streams of thought-African-American, Afro-Caribbean, Asian-American, Feminist, Latin-American, Lesbian, Native-American and Queer-that introduce readers to alternative, complex philosophical questions concerning gendered, sexed, racial and ethnic identities, canon formation, and meta-philosophy. The overriding theme of the text is that philosophy is pluralistic in voice, rich in diversity, and ought to valorize democratic intellectual spaces of philosophical engagement.

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.

This study investigated the perceptions and attitudes of ICU nurses towards the ‘do not resuscitate’ (DNR) decision and changes in their nursing activities after implementation of the DNR decision in South Korea. A data survey was conducted in South Korea between August and October 2008, with a convenience sample of 252 ICU nurses who had more than one year of clinical experience. The data were collected via a self-administered questionnaire. Most of the nurses perceived the necessity of the DNR decision (...) in cases where there would be no chance of patient recovery despite massive efforts. Very few of the nurses' activities changed, either passively or actively, after implementation of the DNR decision. Moreover, the findings of this research provide suggestions for the future direction of the DNR decision and ethical nursing guidelines in South Korea. Further investigations are needed for the development of decision-making skills and intervention guidelines for end-of-life nursing. (shrink)

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)

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)

This research explores the dynamics of interpersonal arguing in South Korea by considering cultural influence, individual traits, and contexts. In a cross-cultural study where Koreans were compared to U.S. Americans on basic measures of argument orientations, several interesting contrasts emerged, along with considerable similarity. Koreans evaluated conflicts more positively than Americans even though they were more worried about the relational consequences of arguing. Within the Korean sample, sex difference was pronounced. Study 2 found that power distance orientation was critical individual-level (...) cultural value for Koreans’ argument motivations. When power distance orientation was controlled, argument partner’s social status was significantly associated with Koreans’ motivation to both avoid and approach arguing but not with verbal aggressiveness. The discussion highlights the importance of considering situational as well as individual factors in intercultural studies. (shrink)

How do communities establish shared communication systems? The Common Knowledge view assumes that symbolic conventions develop through the accumulation of common knowledge regarding communication practices among the members of a community. In contrast with this view, it is proposed that coordinated communication emerges a by‐product of local interactions among dyads. A set of multi‐agent computer simulations show that a population of “egocentric” agents can establish and maintain symbolic conventions without common knowledge. In the simulations, convergence to a single conventional system (...) was most likely and most efficient when agents updated their behavior on the basis of local rather than global, system‐level information. The massive feedback and parallelism present in the simulations gave rise to phenomena that are often assumed to result from complex strategic processing on the part of individual agents. The implications of these findings for the development of theories of language use are discussed. (shrink)

Current understanding of the development of quantity representations is based primarily on performance in the number‐line task. We posit that the data from number‐line tasks reflect the observer's underlying representation of quantity, together with the cognitive strategies and skills required to equate line length and quantity. Here, we specify a unified theory linking the underlying psychological representation of quantity and the associated strategies in four variations of the number‐line task: the production and estimation variations of the bounded and unbounded number‐line (...) tasks. Comparison of performance in the bounded and unbounded number‐line tasks provides a unique and direct way to assess the role of strategy in number‐line completion. Each task produces a distinct pattern of data, yet each pattern is hypothesized to arise, at least in part, from the same underlying psychological representation of quantity. Our model predicts that the estimated biases from each task should be equivalent if the different completion strategies are modeled appropriately and no other influences are at play. We test this equivalence hypothesis in two experiments. The data reveal all variations of the number‐line task produce equivalent biases except for one: the estimation variation of the bounded number‐line task. We discuss the important implications of these findings. (shrink)

The paper aims to provide an analysis and critique of Carl Wellman’s account of conduction presented in Challenge and Response and Morals and Ethics. It considers several issues, including: reason-ing vs. argument, the definition vs. the three patterns of conduction, pro and con arguments as dialogues, their assessment, the concept of validity, applications beyond moral arguments, argument type vs. as crite-rion of evaluation.