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Traditional Concept (traditional + concept)
Selected AbstractsChordate phylogeny and evolution: a not so simple three-taxon problemJOURNAL OF ZOOLOGY, Issue 2 2008T. Stach Abstract Traditional concepts of chordate phylogeny have recently been in turmoil: in a large-scale molecular study, the traditional hypothesis that cephalochordates are sister taxon to craniates was replaced by the hypothesis of a sister group relationship between tunicates and craniates. It was claimed that the morphological evidence that supported traditional phylogeny was weak and that morphological characters at least equally strong could be mustered in support of the ,new phylogeny.' In the present review, it is shown that the uncritical use of published codings of morphological characters in recent phylogenetic analyses is responsible for this perception. To ameliorate this situation, the main focus of the present publication is a review of the morphological evidence that has been deemed relevant in chordate phylogeny. Characters are presented in enough detail to allow readers to make self-reliant informed decisions on character coding. I then analyze these characters cladistically, and it is demonstrated that support of the traditional hypothesis is substantial. I briefly evaluate molecular systematic studies and criticize ,evo-devo' studies for lack of cladistic rigor in the evolutionary interpretations of their data by (1) failing to formally code their characters (2) failing to subject their data to the congruence test with other characters, the crucial test in phylogenetic analyses. Finally, a short and by necessity eclectic discussion of suggested evolutionary scenarios is presented. [source] The Not-So-Simple Process of Sickle Cell VasoocclusionMICROCIRCULATION, Issue 2 2004STEPHEN H. EMBURY ABSTRACT Traditional concepts of sickle cell disease as a monogenically inherited disorder that is understood completely on the basis of polymerization based pathophysiology are more simple that what clinical observations allow. Detailed explications of the determinants of polymerization can be counted, but these do not account for all aspects of sickle cell disease. Neither can all perturbations that count in the course of sickle cell disease be counted as determinants of polymerization. The polymerization based theory that has been extrapolated to describe clinical disease often is not identical to clinical reality. Although contemporary understandings of sickle cell pathophysiology have been described as crazy by those bound to traditional polymerization based understandings, increasingly iconoclastic, seemingly crazy notions are regularly providing important new understandings of sickle cell disease. One of the major challenges to contemporary investigators is to describe new scientific insights in a way that can be understood by others, particularly those reluctant to afford polymerization independent discoveries validity among the interdependent processes that account for sickle cell disease. [source] Task-dependent modulation of functional connectivity between hand motor cortices and neuronal networks underlying language and music: a transcranial magnetic stimulation study in humansEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2007R. Sparing Abstract Although language functions are, in general, attributed to the left hemisphere, it is still a matter of debate to what extent the cognitive functions underlying the processing of music are lateralized in the human brain. To investigate hemispheric specialization we evaluated the effect of different overt musical and linguistic tasks on the excitability of both left and right hand motor cortices using transcranial magnetic stimulation (TMS). Task-dependent changes of the size of the TMS-elicited motor evoked potentials were recorded in 12 right-handed, musically naive subjects during and after overt speech, singing and humming, i.e. the production of melody without word articulation. The articulation of meaningless syllables served as control condition. We found reciprocal lateralized effects of overt speech and musical tasks on motor cortex excitability. During overt speech, the corticospinal projection of the left (i.e. dominant) hemisphere to the right hand was facilitated. In contrast, excitability of the right motor cortex increased during both overt singing and humming, whereas no effect was observed on the left hemisphere. Although the traditional concept of hemispheric lateralization of music has been challenged by recent neuroimaging studies, our findings demonstrate that right-hemisphere preponderance of music is nevertheless present. We discuss our results in terms of the recent concepts on evolution of language and gesture, which hypothesize that cerebral networks mediating hand movement and those subserving language processing are functionally linked. TMS may constitute a useful tool to further investigate the relationship between cortical representations of motor functions, music and language using comparative approaches. [source] MULTILEVEL SELECTION AND THE PARTITIONING OF COVARIANCE: A COMPARISON OF THREE APPROACHESEVOLUTION, Issue 3 2004Samir Okasha Abstract Where the evolution of a trait is affected by selection at more than one hierarchical level, it is often useful to compare the magnitude of selection at each level by asking how much of the total evolutionary change is attributable to each level of selection. Three statistical partitioning techniques, each designed to answer this question, are compared, in relation to a simple multilevel selection model in which a trait's evolution is affected by both individual and group selection. None of the three techniques is wholly satisfactory: one implies that group selection can operate even if individual fitness is determined by individual phenotype alone, whereas the other two imply that group selection can operate even if there is no variance in group fitness. This has significant implications both for our understanding of what the term "multilevel selection" means and for the traditional concept of group selection. [source] The Politics of Social Learning: Finance, Institutions, and Pension Reform in the United States and CanadaGOVERNANCE, Issue 4 2006DANIEL BÉLANDArticle first published online: 27 OCT 200 Because the traditional concept of social learning has faced significant criticism in recent years, more analytical work is required to back the claim that the lessons drawn from existing institutional legacies can truly impact policy outcomes. Grounded in the historical institutionalist literature, this article formulates an amended concept of social learning through the analysis of the relationship between finance, social learning, and institutional legacies in the 1990s debate over the reform of earnings-related pension schemes in the United States and Canada. The article shows how social learning related to specific ideological assumptions and policy legacies in the public and the private sectors has affected policymaking processes. At the theoretical level, this contribution stresses the political construction of learning processes, which is distinct from the technocratic model featured in the traditional literature on social learning. This article also distinguishes between high- and low-profile social learning while emphasizing the impact of private policy legacies on learning processes. [source] Quaternary reactivation of Tertiary faults in the southeastern Korean Peninsula: Age constraint by optically stimulated luminescence datingISLAND ARC, Issue 1 2003Jin-Han Ree Abstract Two groups of Quaternary faults occur in the southeastern Korean Peninsula. The first group is north-northeast-striking, high-angle dextral strike,slip faults. The second group is north-northeast-striking, low-angle reverse faults that represent the reactivation of the pre-existing normal faults. Optically stimulated luminescence dating of Quaternary sediments cut by one of the reverse faults constrains the faulting age to post-32 Ka. These faults seem to be capable of further slip under the current tectonic stress regime, as determined by recent earthquake events in northeast Asia. Therefore, the traditional concept that the southeastern Korean Peninsula is seismically stable should be reappraised. [source] Statistical morphological analysis of hippocampal principal neurons indicates cell-specific repulsion of dendrites from their own cellJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2003Alexei V. Samsonovich Abstract Traditionally, the sources of guidance cues for dendritic outgrowth are mainly associated with external bodies (A) rather than with the same neuron from which dendrites originate (B). To quantify the relationship between factors A and B as determinants of the adult dendritic shape, the morphology of 83 intracellularly characterized, stained, completely reconstructed, and digitized principal neurons of the rat hippocampus was statistically analyzed using Bayesian optimization. It was found that the dominant directional preference (tropism) manifested in dendritic turns is to grow away from the soma rather than toward the incoming fibers or in any other fixed direction; therefore, B is predominant. Results are robust and consistent for all examined morphological classes (dentate gyrus granule cells, basal and apical trees of CA3 and CA1 pyramidal cells). In addition, computer remodeling of neurons based on the measured parameters produced virtual structures consistent with real morphologies, as confirmed by measurement of several global emergent parameters. Thus, the simple description of dendritic shape based on dendrites' tendency to grow straight, away from their own soma, and with additional random deflections, proves remarkably accurate and complete. Although based on adult neurons, these results suggest that dendritic guidance during development may be associated primarily with the host cell. This possibility challenges the traditional concept of dendritic guidance: in that hippocampal cells are densely packed and have highly overlapping dendritic fields, the somatodendritic repulsion must be cell specific. Plausible mechanisms involving extracellular effects of spikes are discussed, together with feasible experimental tests and predicted results. © 2002 Wiley-Liss, Inc. [source] On Robert Jenson's Trinitarian ThoughtMODERN THEOLOGY, Issue 1 2002Brian K. Sholl This paper addresses Robert Jenson's critique of impassibility along with his Trinitarian formulations. Jenson's decision to eschew a doctrine of divine impassibility leads him to adopt a Kantian conception of subjectivity in order to explicate the traditional concept of hypostasis. In turn, Jenson advocates a Hegelian notion of determinate negation to relate to a concept of being dependent upon a German Idealist figuration of temporality. The final section of the paper contrasts Jenson's modernist immanentism with the positive perichoretic movement of Jonathan Edwards' trinitarian thought. For Edwards, the Trinity cannot be known as a repeatable object of knowledge reflected within human consciousness, but as a non-identical repletion of eternal love to which univocal categories do not apply. [source] The concept of disease: ethical challenges and relevance to dentistry and dental educationEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 1 2001Bjørn M. Hofmann Modern medicine and dentistry face fundamental ethical challenges. To treat or not to treat, that is the question! Can these challenges be met with a rigorous and consistent concept of disease? This is the key question of this article and the ensuing debate is of fundamental importance in the teaching of ethics to medical and dental students. The investigation of traditional concepts of disease reveals that they are flawed and do not withstand ethical challenges. An alternative concept of human ailment is elaborated on, based on the triad disease, illness and sickness. This model is applied to representative cases in medicine in general and dentistry in particular. It is argued that the concepts of disease, illness and sickness represent a framework for analysing and coping with inherent ethical challenges. This reveals that medicine and dentistry are concerned both with biological explanations and with questions of the virtuous life, i.e., both with science and with ethics. These considerations pose challenges for the health professions as a whole, but particularly for those concerned with educating the practitioners of the future. [source] Using historical ecology to understand patterns of biodiversity in fragmented agricultural landscapesJOURNAL OF BIOGEOGRAPHY, Issue 11 2005Ian D. Lunt Abstract Aim, To enhance current attempts to understand biodiversity patterns by using an historical ecology approach to highlight the over-riding influence of land-use history in creating past, current and future patterns of biodiversity in fragmented agricultural landscapes. Methods, We develop an integrative conceptual framework for understanding spatial and temporal variations in landscape patterns in fragmented agricultural landscapes by presenting five postulates (hypotheses) which highlight the important role of historical, anthropogenic disturbance regimes. We then illustrate each of these postulates with examples drawn from fragmented woodlands in agricultural areas of south-eastern Australia, and discuss these findings in an international context. Location examples are drawn from agricultural areas in south-eastern Australia. Results, We conclude that there is limited potential to refine our understanding of patterns of biodiversity in human-modified landscapes based on traditional concepts of island biogeography, or simple assumptions of ongoing destruction and degradation. Instead, we propose that in agricultural landscapes that were largely cleared over a century ago: (1) present-day remnant vegetation patterns are not accidental, but are logically arrayed due to historic land-use decisions, (2) historic anthropogenic disturbances have a major influence on current ecosystem conditions and diversity patterns, and (3) the condition of remnant ecosystems is not necessarily deteriorating rapidly. Main conclusions, An historical ecology approach can enhance our understanding of why different species and ecosystem states occur where they do, and can explain internal variations in ecological conditions within remnant ecosystems, too often casually attributed to the ,mess of history'. This framework emphasizes temporal changes (both past and future) in biotic patterns and processes in fragmented agricultural landscapes. Integration of spatially and temporally explicit historical land-use information into ecological studies can prove extremely useful to test hypotheses of the effects of changes in landscape processes, and to enhance future research, restoration and conservation management activities. [source] Particulate delivery systems for vaccines: what can we expect?JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2006Vincent W. Bramwell In our attempts to thwart the unwanted attentions of microbes by prophylactic and therapeutic vaccination, the knowledge of interactions at the molecular level may prove to be an invaluable asset. This article examines how particulate delivery systems such as liposomes and polymer micro-spheres can be applied in the light of recent advances in immunological understanding. Some of the biological interactions of these delivery systems are discussed with relevance for antigen trafficking and molecular pathways of immunogenicity and emphasis on the possible interaction of liposomal components. In particular, traditional concepts such as antigen protection, delivery to antigen presenting cells and depot formation remain important aspects, whilst the inclusion of selected co-adjuvants and enhanced delivery of these moieties in conjunction with antigen now has a firm rationale. [source] The role of second health professionals under New Zealand mental health legislationJOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 3 2006A. J. O'BRIEN rgn rpn ba mphil The development of generic statutory roles in mental health care has been the subject of discussion by New Zealand nurses for the past decade. One such role is that of second health professional in judicial reviews of civil commitment. Issues identified by New Zealand nurses have also been raised in England, where it seems that nurses are likely to assume the role of Approved Mental Health Worker under English mental health law. A survey of mental health nurses found that few had received any preparation for the role of second health professional and 45% did not feel adequately prepared for the role. Some of these issues are reflected in a New Zealand inquiry which resulted in the Ministry of Health developing a written report form for second health professionals. However, the form has the potential to reduce the mental health nursing role to a narrow legal role. Statutory roles such as that of second health professional challenge mental health nurses to critically reflect on the conceptual and ethical basis of their practice. While traditional concepts such as therapeutic relationships and advocacy need to be reviewed in light of these changes, nurses need to be vigilant in articulating the moral and clinical basis of their roles. The development of guidelines for he second health professional role is suggested as a way of supporting clinical practice in this area. [source] | ||||||||||||||||