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Unwarranted Assumptions (unwarranted + assumption)

Distribution by Scientific Domains
Life Sciences50%

Selected Abstracts

Gain functions for large herbivores: tests of alternative models

JOURNAL OF ANIMAL ECOLOGY, Issue 1 2005
KATE R. SEARLE
Summary 1The gain function describes the amount of food consumed in a patch as a function of patch residence time. Gain functions play a central role in foraging theory but alternative functional forms portraying dynamics of gain have not been evaluated. We evaluated the strength of evidence in the data for alternative gain functions of mule deer (Odocoileus hemionus, Rafinesque 1817) and blue duikers (Cephalophus monticola, Blythe 1848) feeding in patches composed of different plant species and plant sizes. 2Gain functions decelerated with patch residence time, but there was considerable variation among individual animals and patch types in the nature of this response. Asymptotic and piecewise-linear models received the greatest support in the data. 3Deceleration in gain was caused by a composite of effects that retarded instantaneous intake rate, including reductions in bite mass and increases in bite interval (time between successive bites). Bite interval increased as a result of increases in processing time of accumulated forage in the mouth, rather than increases in time allocated to cropping. 4We demonstrated that unwarranted assumptions about the shape of gain functions can have profound effects on predictions of patch models. Predictions of the classical patch model using purely asymptotic gain functions contrasted sharply with predictions of model-averaged gain functions that were supported by the data. [source]

The Wildlife Picture Index: monitoring top trophic levels

ANIMAL CONSERVATION, Issue 4 2010
T. G. O'Brien
Abstract Although recent biodiversity loss has been compared with cataclysmic mass extinctions, we still possess few indicators that can assess the extent or location of biodiversity loss on a global scale. The Convention on Biological Diversity (CBD) has mandated development of indicators that can meet the needs of monitoring biodiversity by 2010. To date, many indicators rely on unwarranted assumptions, secondary data, expert opinion and retrospective time series. We present a new biodiversity indicator, the Wildlife Picture Index (WPI) that targets medium and large-sized terrestrial birds and mammals in forested and savannah ecosystems that. The WPI is a composite indicator based on the geometric mean of relative occupancy estimates derived from camera trap sampling at a landscape scale. It has been designed to meet the needs of a CBD indicator while avoiding many of the pitfalls that characterize some CBD indicators. We present an example using 8 years of camera trap data from Bukit Barisan Selatan National Park, Indonesia to show that the WPI is capable of detecting changes in the rate of loss of biodiversity, a key requirement of a CBD indicator. We conclude that the WPI should be effective at monitoring top trophic levels in forest and savannah ecosystems using primary data and can fill the gap in knowledge about trends in tropical biodiversity. [source]

The Marketization of Education: Public Schools for Private Ends

ANTHROPOLOGY & EDUCATION QUARTERLY, Issue 1 2002
Assistant Professor Lesley Bartlett
This article argues that the neoliberal renaissance of the 1980s marketized education, with distinctly negative social consequences. We examine the emergence and promotion of a national-level discourse that positioned schools in the service of the economy. Based on ethnographic research conducted in North Carolina, we then show how local growth elite utilized this discourse to further their own race and class interests to the exclusion and detriment of poorer, African American parents and students. We suggest that ethnographic studies of policy formation help to socially and historically contextualize contemporary debates and denaturalize unwarranted assumptions about the public good. [source]

Industrial and Organisation Research on Self-Regulation: From Constructs to Applications

APPLIED PSYCHOLOGY, Issue 2 2005
Jeffrey B. Vancouver
L'autorégulation rencontre actuellement du succès en psychologie industrielle et organisationnelle. Les travaux théoriques et empiriques englobent des processus allant de l'entrée dans l'organisation à la sortie et à la réembauche. Les interventions et les concepts clés de l'autorégulation dans le monde du travail sont recensés en insistant sur la validité interne et de construction. Quelques concepts comme l'efficacité personnelle et l'implication ont bénéficié d'un grand intérêt de la part des psychométriciens et semblent constituer des cibles de premier ordre lors des interventions. Néanmoins, ces concepts restent entachés d'hypothèses dont la validité n'est pas garantie. D'autres concepts, en particulier la rétroaction et la divergence, souffrent de significations sensiblement différentes dans la littérature sur l'autorégulation, ce qui nuit à la compréhension et à la communication entre les universitaires et les praticiens. On a lancé des interventions relevant des principes de l'autorégulation; celles-ei ont ensuite étéévaluées avec sérieux: il est apparu qu'elles avaient un impact sur un ensemble de variables pertinentes du point de vue organisationnel comme l'amélioration des performances et la réduction de l'absentéisme. Malheureusement, les interventions sont rarement étudiées de façon détaúllée et systématique, ce qui ne permet pas de tirer des conclusions sur les aspects de l'intervention qui sont pertinents du point de vue de la causalité. La discussion insiste sur les lacunes dans la connaissance et l'appréhension des processus de l'autorégulation dans les contextes organisationnels, ainsi que sur la façon dont la discipline pourrait tenter de combler ces lacunes. The self-regulation perspective is currently well received in the industrial and organisational psychology literature. Theoretical and empirical work span processes ranging from organisation entry to exit and reentry. Key self-regulation constructs and interventions in work contexts are reviewed with a focus on construct and internal validity. Some constructs, such as self-efficacy and goal commitment, have received substantial psychometric attention and seem important targets for interventions. Nonetheless, potentially unwarranted assumptions remain regarding these constructs. Other constructs, particularly feedback and discrepancy, have acquired substantially different meanings within the self-regulation literature that inhibit understanding and communication among scholars and practitioners. Interventions based on self-regulatory principles have been developed, and rigorous tests of these interventions have been conducted. These interventions were found to influence a range of organisationally relevant outcomes such as increasing performance and reducing absenteeism. Unfortunately, studies of comprehensive interventions are rare and often lacked controls, making it difficult to draw conclusions regarding what aspects of the interventions are causally relevant. Discussion focuses on the gaps in the field's knowledge and understanding regarding self-regulatory processes in organisational settings and how the field might attempt to fill those gaps. [source]