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Central Goal (central + goal)
Selected AbstractsGenerality with specificity: the dynamic field theory generalizes across tasks and time scalesDEVELOPMENTAL SCIENCE, Issue 4 2008Vanessa R. Simmering A central goal in cognitive and developmental science is to develop models of behavior that can generalize across both tasks and development while maintaining a commitment to detailed behavioral prediction. This paper presents tests of one such model, the Dynamic Field Theory (DFT). The DFT was originally proposed to capture delay-dependent biases in spatial recall and developmental changes in spatial recall performance. More recently, the theory was generalized to adults' performance in a second spatial working memory task, position discrimination. Here we use the theory to predict a specific, complex developmental pattern in position discrimination. Data with 3- to 6-year-old children and adults confirm these predictions, demonstrating that the DFT achieves generality across tasks and time scales, as well as the specificity necessary to generate novel, falsifiable predictions. [source] Microevolutionary support for a developmental hourglass: gene expression patterns shape sequence variation and divergence in DrosophilaEVOLUTION AND DEVELOPMENT, Issue 5 2008Tami Cruickshank SUMMARY A central goal of evolutionary developmental biology (Evo-Devo) is to synthesize comparative molecular developmental genetics and its description of the dynamic relationship between genotype and phenotype with the microevolutionary processes (mutation, random drift, and selection) of population genetics. To this end, we analyzed sequence variation of five gene classes that act sequentially to shape early embryo development in Drosophila: maternal, gap, pair-rule, segment polarity, and segment identity genes. We found two related patterns: (1) a microevolutionary pattern, wherein relative sequence variation within species is 2- to 3-fold higher for maternal-effect genes than for any other gene class; and, (2) a macroevolutionary pattern, wherein the relative sequence divergence among species for maternal-effect genes is 2- to 4-fold greater than for any other gene class. Both patterns are qualitatively and quantitatively consistent with the predictions of microevolutionary theory. Our findings connect within-species genetic variation to between-species divergence and shed light on the controversy over the existence of a "developmental hourglass," where mid-embryonic stages are more evolutionarily constrained than either earlier or later stages. Because maternal-effect genes experience relaxed selective constraint relative to zygotic-effect genes, they explore a wider mutational and phenotypic space. As a result, early acting maternal-effect genes diverge more widely across taxa and thereby broaden the base of the developmental hourglass. In contrast, later acting zygotic genes are relatively more constrained and limited in their diversification across taxa, narrowing the waist of the developmental hourglass. This pattern is obscured by genes with both maternal and zygotic expression, which experience the strongest evolutionary constraint. [source] The Fate of Jewish Historiography after the Bible: A New InterpretationHISTORY AND THEORY, Issue 2 2004Amram Tropper What caused the eventual decline in later Jewish history of the vibrant historiographical tradition of the biblical period? In contrast to the plethora of historical writings composed during the biblical period, the rabbis of the early common era apparently were not interested in writing history, and when they did relate to historical events they often introduced mythical and unrealistic elements into their writings. Scholars have offered various explanations for this phenomenon; a central goal of this article is to locate these explanations within both the immediate historical setting of Roman Palestine and the overarching cultural atmosphere of the Greco-Roman Near East. In particular, I suggest that the largely ahistorical approach of the rabbis functioned as a local Jewish counterpart to the widespread classicizing tendencies of a contemporary Greek intellectual movement, the Second Sophistic. In both cases, eastern communities, whose political aspirations were stifled under Roman rule, sought to express their cognitive and spiritual identities by focusing on a glorious and idealized past rather than on contemporary history. Interestingly, the apparent lack of rabbinic interest in historiography is not limited to the early rabbinic period. Throughout the Middle Ages and into the Renaissance, Jews essentially did not write their political, diplomatic, or military history. Instead, Jews composed "traditional historiography" which included various types of literary genres among which the rabbinic "chain of transmission" was the most important. The chain of transmission reconstructs (or fabricates) the links that connect later rabbinic sages with their predecessors. Robert Bonfil has noted the similarity between this rabbinic project and contemporary church histories. Adding a diachronic dimension to Bonfil's comparison, I suggest that rabbinic chains of transmission and church histories are not similar though entirely independent phenomena, but rather their shared project actually derives from a common origin, the Hellenistic succession list. The succession list literary genre, which sketches the history of an intellectual discipline, apparently thrived during the Second Sophistic and diffused then into both rabbinic Judaism and early Christianity. Thus, even though historiography was not terribly important to the early rabbis or to most Second Sophistic intellectuals, the succession list schematic, or the history of an intellectual discipline, was evaluated differently. Rabbis and early Christians absorbed the succession list from Second Sophistic culture and then continued to employ this historiographical genre for many centuries to come. [source] Spatial regression techniques for inter-population data: studying the relationships between morphological and environmental variationJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2010S. I. PEREZ Abstract Understanding the importance of environmental dimensions behind the morphological variation among populations has long been a central goal of evolutionary biology. The main objective of this study was to review the spatial regression techniques employed to test the association between morphological and environmental variables. In addition, we show empirically how spatial regression techniques can be used to test the association of cranial form variation among worldwide human populations with a set of ecological variables, taking into account the spatial autocorrelation in data. We suggest that spatial autocorrelation must be studied to explore the spatial structure underlying morphological variation and incorporated in regression models to provide more accurate statistical estimates of the relationships between morphological and ecological variables. Finally, we discuss the statistical properties of these techniques and the underlying reasons for using the spatial approach in population studies. [source] Co-evolution of plumage characteristics and winter sociality in New and Old World sparrowsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 12 2009E. A. TIBBETTS Abstract Understanding the evolution of phenotypic diversity, including the stunning array of avian plumage characters, is a central goal of evolutionary biology. Here, we applied a comparative analysis to test factors associated with the origin and maintenance of black chest and throat patches, which in some taxa are referred to as ,badges-of-status'. Specifically, we tested whether the evolution of black colour patches in Old and New World sparrows is consistent with a signalling function during the nonbreeding season or breeding season. We found no positive associations between patch evolution and polygyny or summer sociality. Instead, patch evolution is significantly associated with sociality during the nonbreeding season. Additionally, unlike typical plumage characteristics under sexual selection, these patches are visible throughout the nonbreeding season. Further, the pattern of patch dimorphism uncovered in this study does not match expectations for a trait that evolved in a reproductive context. In particular, patch dimorphism is not associated with polygyny or the presence of extra-pair mating although other types of plumage dimorphism are strongly associated with nonmonogamous mating systems. Overall, patterns of patch evolution suggest that they are more strongly associated with social competition during the nonbreeding season than sexual competition during the breeding season. These results clarify why some previous work has uncovered puzzling relationships between black plumage patches and reproductive behaviour. We discuss these findings in the context of signal theory and previous work on badges-of-status. [source] 122 Local to Coastal-Scale Macrophyte Community Structure: Surprizing Patterns and Possible MechanismsJOURNAL OF PHYCOLOGY, Issue 2003B. A. Menge Understanding large-scale patterns in ecological communities is a central goal of ecology, and yet, rigorous quantitative geographic data on distribution, abundance and diversity are almost totally lacking. Even in rocky intertidal habitats, our data on community structure are spatially and temporally limited, with most surveys limited to a few sites over short time periods. When linked to studies of community dynamics on similar scales, such studies should provide insights into the determinants of pattern at more relevant scales. In 1999 PISCO, the Partnership for Interdisciplinary Studies of Coastal Oceans, initiated survey programs aimed at determining patterns of community structure along the US west coast from Washington to Baja California. Sites are regularly spaced along the coast in a nested design, and were physically similar. Surveys used randomly placed quadrats in transects run parallel to shore in high, mid and low zones. Results show that, contrary to expectation, macroalgal diversity along the northern coast was higher, not lower than that along the southern coast. Possible factors associated with this unexpected pattern include along-coast variation in tidal amplitude, time of tide, thermal stress, upwelling intensity and resulting nutrient gradients, disturbance from storms or sand burial, and grazing. We review evidence relevant to these factors, and focus on the possible role of grazing, using field experiments done under differing oceanographic conditions along the Oregon coast as a model. Although short-term grazing rates can vary with oceanographic condition, we hypothesize that despite these results and those of many similar studies showing strong grazing effects on local spatial and short time scales, that bottom-up factors are stronger determinants of macroalgal community structure on larger spatial scales and longer time scales. [source] Views of nature of science questionnaire: Toward valid and meaningful assessment of learners' conceptions of nature of scienceJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 6 2002Norm G. Lederman Helping students develop informed views of nature of science (NOS) has been and continues to be a central goal for kindergarten through Grade 12 (K,12) science education. Since the early 1960s, major efforts have been undertaken to enhance K,12 students and science teachers' NOS views. However, the crucial component of assessing learners' NOS views remains an issue in research on NOS. This article aims to (a) trace the development of a new open-ended instrument, the Views of Nature of Science Questionnaire (VNOS), which in conjunction with individual interviews aims to provide meaningful assessments of learners' NOS views; (b) outline the NOS framework that underlies the development of the VNOS; (c) present evidence regarding the validity of the VNOS; (d) elucidate the use of the VNOS and associated interviews, and the range of NOS aspects that it aims to assess; and (e) discuss the usefulness of rich descriptive NOS profiles that the VNOS provides in research related to teaching and learning about NOS. The VNOS comes in response to some calls within the science education community to go back to developing standardized forced-choice paper and pencil NOS assessment instruments designed for mass administrations to large samples. We believe that these calls ignore much of what was learned from research on teaching and learning about NOS over the past 30 years. The present state of this line of research necessitates a focus on individual classroom interventions aimed at enhancing learners' NOS views, rather than on mass assessments aimed at describing or evaluating students' beliefs. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 497,521, 2002 [source] Epistemic Presuppositions and their ConsequencesMETAPHILOSOPHY, Issue 1-2 2003Juli Eflin Traditional epistemology has, in the main, presupposed that the primary task is to give a complete account of the concept knowledge and to state under what conditions it is possible to have it. In so doing, most accounts have been hierarchical, and all assume an idealized knower. The assumption of an idealized knower is essential for the traditional goal of generating an unassailable account of knowledge acquisition. Yet we, as individuals, fail to reach the ideal. Perhaps more important, we have epistemic goals not addressed in the traditional approach , among them, the ability to reach understanding in areas we deem important for our lives. Understanding is an epistemic concept. But how we obtain it has not traditionally been a focus. Developing an epistemic account that starts from a set of assumptions that differ from the traditional starting points will allow a different sort of epistemic theory, one on which generating understanding is a central goal and the idealized knower is replaced with an inquirer who is not merely fallible but working from a particular context with particular goals. Insight into how an epistemic account can include the particular concerns of an embedded inquirer can be found by examining the parallels between ethics and epistemology and, in particular, by examining the structure and starting points of virtue accounts. Here I develop several interrelated issues that contrast the goals and evaluative concepts that form the structure of both standard, traditional epistemological and ethical theories and virtue,centered theories. In the end, I sketch a virtue,centered epistemology that accords with who we are and how we gain understanding. [source] Mechanisms in macroecology: AWOL or purloined letter?OIKOS, Issue 4 2010Towards a pragmatic view of mechanism Ecologists often believe the discovery of mechanism to be the central goal of scientific research. While many macroecologists have inherited this view, to date they have been much more efficient at producing patterns than identifying their underlying processes. We discuss several possible attitudes for macroecologists to adopt in this context while also arguing that in fact macroecology already has many mechanisms that are ignored. We briefly describe six of these: central limit theorem, fractals, random sampling and placement, neutral theory (and descendents), concordance of forces, and maximum entropy. We explore why these mechanisms are overlooked and discuss whether they should be. We conclude that macroecology needs to take a more pragmatic, less ideological approach to mechanism. We apply this viewpoint to the recent controversy over maximum entropy and suggest that maximum entropy needs to be viewed more pragmatically and less ideologically. [source] Insulin therapy and quality of life.DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue S1 2009A review Abstract Three central goals in the treatment of diabetes mellitus are (1) the avoidance of hyperglycaemia to prevent the development or progression of diabetes complications over time, (2) the avoidance of hypoglycaemia and (3) the maintenance or achievement of good quality of life. Insulin is the most powerful agent that can be used to control blood glucose levels. This article reviews the studies that have investigated the effects of different types of insulin and insulin delivery techniques on quality of life of patients with type 1 or type 2 diabetes. First, the concept of ,quality of life' (QoL) is defined and different ways of measuring QoL are explained. Secondly, the effects of different aspects of insulin therapy on QoL are reviewed: (1) the phenomenon of ,psychological insulin resistance'; (2) the effects of different types of insulin: regular insulin versus short-acting insulin analogues, long-acting insulin analogues or biphasic mixtures; (3) multiple daily injections versus pump therapy. Having multiple complications of diabetes is clearly associated with decreased QoL. Results from large studies such as the Diabetes Control and Complications Trial (DCCT) and United Kingdom Prospective Diabetes Study (UKPDS) suggest that intensive treatment itself does not impair QoL. Recent findings further suggest that pump therapy, compared to multiple daily injections, has beneficial effects on QoL. The fact that multiple tools are used to assess QoL makes it difficult to draw conclusions regarding the effects of different types of insulin on QoL. More work on the standardization of the assessment of QoL in diabetes is urgently needed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Challenges in the application of geometric constraint modelsGLOBAL ECOLOGY, Issue 3 2007Craig R. McClain ABSTRACT Discerning the processes influencing geographical patterns of species richness remains one of the central goals of modern ecology. Traditional approaches to exploring these patterns have focused on environmental and ecological correlates of observed species richness. Recently, some have suggested these approaches suffer from the lack of an appropriate null model that accounts for species ranges being constrained to occur within a bounded domain. Proponents of these null geometric constraint models (GCMs), and the mid-domain effect these models produce, argue their utility in identifying meaningful gradients in species richness. This idea has generated substantial debate. Here we discuss what we believe are the three major challenges in the application of GCMs. First, we argue that there are actually two equally valid null models for the random placement of species ranges within a domain, one of which actually predicts a uniform distribution of species richness. Second, we highlight the numerous decisions that must be made to implement a GCM that lead to marked differences in the predictions of the null model. Finally, we discuss challenges in evaluating the importance of GCMs once they have been implemented. [source] | |||||||||||||||||||||||||