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Traditional Studies (traditional + studies)

Distribution by Scientific Domains

Medical Sciences	37%
Life Sciences	37%

Selected Abstracts

The complexity of school and neighbourhood effects and movements of pupils on school differences in models of educational achievement

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 3 2009
George Leckie
Summary., Traditional studies of school differences in educational achievement use multilevel modelling techniques to take into account the nesting of pupils within schools. However, educational data are known to have more complex non-hierarchical structures. The potential importance of such structures is apparent when considering the effect of pupil mobility during secondary schooling on educational achievement. Movements of pupils between schools suggest that we should model pupils as belonging to the series of schools that are attended and not just their final school. Since these school moves are strongly linked to residential moves, it is important to explore additionally whether achievement is also affected by the history of neighbourhoods that are lived in. Using the national pupil database, this paper combines multiple membership and cross-classified multilevel models to explore simultaneously the relationships between secondary school, primary school, neighbourhood and educational achievement. The results show a negative relationship between pupil mobility and achievement, the strength of which depends greatly on the nature and timing of these moves. Accounting for pupil mobility also reveals that schools and neighbourhoods are more important than shown by previous analysis. A strong primary school effect appears to last long after a child has left that phase of schooling. The additional effect of neighbourhoods, in contrast, is small. Crucially, the rank order of school effects across all types of pupil is sensitive to whether we account for the complexity of the multilevel data structure. [source]

A scalar analysis of landscape connectivity

OIKOS, Issue 2 2003
Article first published online: 4 JUL 200
Landscape connectivity is critical to the maintenance of spatially-structured populations and consists of both a structural component, which describes the shape, size and location of landscape features; and a biological component, which consists of both the response of individuals to landscape features, and the patterns of gene flow that result from those individual responses. Traditional studies of landscape connectivity have attempted to discern individual behavioral responses to landscape features, but this methodology is intractable for many species. This paper is an attempt to relate the components of landscape connectivity through the explicit treatment of their spatial and temporal scales. Traditional measures of structural and biological components of connectivity are reviewed and more recently developed methods for the analysis of scale for each are introduced. I then present a framework for the comparison of scalar phenomena based on Watt's unit pattern, describe the potential outcomes of the comparison and discuss the implications of each. Several testable hypotheses emerge from the analysis that may serve as a useful framework for the investigation of landscape connectivity in the future. [source]

Substantive Symbols: The Attitudinal Dimension of Black Political Incorporation in Local Government

AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 1 2007
Melissa J. Marschall
Traditional studies of minority incorporation focus on the redistribution of public resources that purportedly follows black gains in representation. The present study departs from this approach by focusing on the attitudinal effects of black leadership. Two research questions guide this study: To what extent do blacks' assessments of neighborhood services and conditions stem from black representation in local executive and legislative offices? Are these attitudinal effects rooted in policy and service delivery outcomes? Employing survey data from 3,000 blacks embedded in 52 cities and 53 school districts, this study reveals that blacks report higher levels of satisfaction with their neighborhood conditions, police services, and public schools when represented by blacks in city hall and on school boards and that these evaluations are most positive when improvements in local services are conspicuous. Overall, these findings extend conventional conceptualizations of substantive benefits and challenge more pessimistic accounts regarding the effects of black representation in local politics. [source]

The role of allergen challenge chambers in the evaluation of anti-allergic medication: an international consensus paper

CLINICAL & EXPERIMENTAL ALLERGY REVIEWS, Issue 2 2006
J. H. Day
Summary Allergic rhinitis (AR) is a common condition with quality of life and economic implications for those affected. Numerous studies have attempted to evaluate treatments for rhinitis, seeking clinically meaningful efficacy and safety results to enable evidence-based treatment decisions. Traditional studies of medications for AR are hampered by many confounding environmental factors as well as suboptimal medication compliance. They are also an unsuitable setting for determination of precise pharmacodynamic properties of medications, including onset and duration of action. Allergen challenge chambers (ACCs) were developed to provide predetermined, controlled allergen levels and to limit variables inherent in traditional studies. An ACC hosts a number of allergen-sensitive subjects who may receive either medication or placebo in a closed environment regulated for temperature, humidity and other variables. Subjects' allergic responses are monitored using subjective and objective assessments throughout the study, and the resultant information contributes significantly to the clinical profile of a medication. This consensus paper provides an in-depth review of the role of ACCs as a means to evaluate treatments in AR, and concludes that ACC trials fulfil an important supportive role in the assessment of anti-allergic medication. [source]

Comparison of serological markers of inflammatory bowel disease with clinical diagnosis in children

INFLAMMATORY BOWEL DISEASES, Issue 3 2004
Sandeep K. Gupta MD
Abstract Background: Our purpose was to study the concordance of serological tests for inflammatory bowel disease with clinical diagnosis established by traditional testing in children. Methods: All children seen in our division who had IBD Diagnostic System (ie, pANCA, ASCA IgA, and ASCA IgG) performed over a 21-month period (June 1998 to February 2000) were identified. Their medical records were reviewed for basic demographics, test results (endoscopy, histology, and radiology), IBD Diagnostic System results, and patient symptoms/medications. Results of the IBD Diagnostic System were compared with several patient characteristics including age, sex, absence/presence of symptoms, medication use, disease activity and duration. Results: One hundred seven patients were divided into 6 groups based on clinical diagnosis and IBD Diagnostic System results. The sensitivity, specificity and +/, predictive values of the IBD Diagnostic System for ulcerative colitis were 69.2, 95.1, 90.0, and 87.1%, respectively, and for Crohn's disease were 54.1, 96.8, 90.9, and 80.8%, respectively. Overall, the results of the IBD Diagnostic System were concordant with the clinical diagnosis in 76 of the 107 (71%) patients. Conclusions: In our experience, the specificity of IBD Diagnostic System is better than the sensitivity; the sensitivity is better for ulcerative colitis than Crohn's disease (69.2% vs 54.1%). The low sensitivity, especially for Crohn's disease, precludes the possibility that the IBD Diagnostic System can replace traditional studies when evaluating for inflammatory bowel disease. Though we do not exclude inflammatory bowel disease solely by IBD Diagnostic System results, it is reassuring to note that all patients without clinical evidence of inflammatory bowel disease also had negative IBD Diagnostic System results. [source]

Beta diversity of plant,insect food webs in tropical forests: a conceptual framework

INSECT CONSERVATION AND DIVERSITY, Issue 1 2009
VOJTECH NOVOTNY
Abstract., 1Beta diversity of plant,herbivore food webs, defined as turnover of trophic interactions between the food webs, represents a potentially useful extension of traditional studies of plant and herbivore beta diversity as it integrates spatial turnover of plant and herbivore species with changes in herbivore host plant preferences. 2Beta diversity of plant,herbivore food webs can be partitioned into four components, corresponding to the turnover of plant,herbivore interactions due to change in (i) both plant and herbivore species, (ii) plant, but not herbivore, species, (iii) herbivore, but not plant, species, and (iv) herbivore host preferences between food webs. These components can be quantified using a range of existing beta diversity indices. 3Relative magnitude of plant and herbivore beta diversity of plant,herbivore food webs can be analysed as an outcome of herbivore (i) host specificity, (ii) ability to track host plant populations by dispersal, and (iii) response to environmental conditions, competitors and enemies. The relative importance of these factors in tropical ecosystems remains to be determined. [source]

Breeding birds on small islands: island biogeography or optimal foraging?

JOURNAL OF ANIMAL ECOLOGY, Issue 2 2006
GARETH J. RUSSELL
Summary 1We test MacArthur and Wilson's theory about the biogeography of communities on isolated habitat patches using bird breeding records from 16 small islands off the coasts of Britain and Ireland. 2A traditional examination of patterns of species richness on these islands suggests that area and habitat diversity are important predictors, but that isolation and latitude have a negligible impact in this system. 3Unlike traditional studies, we directly examine the fundamental processes of colonization and local extinction (cessation of breeding), rather than higher-order phenomena such as species richness. 4We find that many of MacArthur and Wilson's predictions hold: colonization probability is lower on more isolated islands, and extinction probability is lower on larger islands and those with a greater diversity of habitats. 5We also find an unexpected pattern: extinction probability is much lower on more isolated islands. This is the strongest relationship in these data, and isolation is the best single predictor of colonization and extinction. 6Our results show that examination of species richness alone is misleading. Isolation has a strong effect on both of the dynamic processes that underlie richness, and in this system, the reductions in both colonization and extinction probability seen on more distant islands have opposing influences on species richness, and largely cancel each other out. 7We suggest that an appropriate model for this system might be optimal foraging theory, which predicts that organisms will stay longer in a resource patch if the distance to a neighbouring patch is large. If nest sites and food are the resources in this system, then optimal foraging theory predicts the pattern we observe. 8We advance the hypothesis that there is a class of spatial systems, defined by their scale and by the taxon under consideration, at which decision-making processes are a key driver of the spatiotemporal dynamics. The appropriate theory for such systems will be a hybrid of concepts from biogeography/metapopulation theory and behavioural ecology. [source]