42,591 research outputs found
The dynamics of acculturation: an intergroup perspective
The growing global trend of migration gives social psychological enquiry into acculturation processes particular contemporary relevance. Inspired by one of the earliest definitions of acculturation [Redfield, R., Linton, R., & Herskovits, M. (1936). Memorandum on the study of acculturation. American Anthropologist,38, 149152.], we present a case for considering acculturation as a dynamic intergroup process. We first review research stimulated by the dominant perspective in the field, Berry's acculturation framework. Noting several limitations of that work, we identify five issues which have defined our own research agenda: (1) the mutual influence of acculturation preferences and intergroup attitudes; (2) the influence of the perceived acculturation preferences of the outgroup on own acculturation and intergroup attitudes; (3) discrepancies between ingroup and outgroup acculturation attitudes as a determinant of intergroup attitudes; (4) the importance of the intergroup climate in which acculturation takes place; and (5) acculturation as a processdevelopmental and longitudinal perspectives. We review research of others and our own that document each of these points: longitudinal and experimental studies, rarities in the acculturation literature, figure prominently. Research settings include TurkishGerman relations in Germany, indigenousnonindigenous relations in Chile, African migrants to Italy and ethnic majorityminority relations in the United Kingdom. We conclude with an agenda for future acculturation research and some policy implications of our analysis
Ethnic Education: A Clash of Cultures in Progressive Chicago
The City of Chicago recently embarked upon a pioneering effort to transform the quality of its public school system. The concept of decentralization that allows for neighborhood councils, greater decision-making at the local level, and increased parental involvement in the schools is not a new one. Similar governance structures of a century ago fell victim to class and ethnic factionalism. The progressive vision of a homogenous society assumed a passive clientele and a consensus culture. Particular educational programs brought diverse groups closer to the mainstream, but the resultant mass culture accommodated pluralistic values rather than the sought-after homogeneity
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Exome resequencing and GWAS for growth, ecophysiology, and chemical and metabolomic composition of wood of Populus trichocarpa.
BackgroundPopulus trichocarpa is an important forest tree species for the generation of lignocellulosic ethanol. Understanding the genomic basis of biomass production and chemical composition of wood is fundamental in supporting genetic improvement programs. Considerable variation has been observed in this species for complex traits related to growth, phenology, ecophysiology and wood chemistry. Those traits are influenced by both polygenic control and environmental effects, and their genome architecture and regulation are only partially understood. Genome wide association studies (GWAS) represent an approach to advance that aim using thousands of single nucleotide polymorphisms (SNPs). Genotyping using exome capture methodologies represent an efficient approach to identify specific functional regions of genomes underlying phenotypic variation.ResultsWe identified 813 K SNPs, which were utilized for genotyping 461 P. trichocarpa clones, representing 101 provenances collected from Oregon and Washington, and established in California. A GWAS performed on 20 traits, considering single SNP-marker tests identified a variable number of significant SNPs (p-value < 6.1479E-8) in association with diameter, height, leaf carbon and nitrogen contents, and δ15N. The number of significant SNPs ranged from 2 to 220 per trait. Additionally, multiple-marker analyses by sliding-windows tests detected between 6 and 192 significant windows for the analyzed traits. The significant SNPs resided within genes that encode proteins belonging to different functional classes as such protein synthesis, energy/metabolism and DNA/RNA metabolism, among others.ConclusionsSNP-markers within genes associated with traits of importance for biomass production were detected. They contribute to characterize the genomic architecture of P. trichocarpa biomass required to support the development and application of marker breeding technologies
Multiscale metabolic modeling of C4 plants: connecting nonlinear genome-scale models to leaf-scale metabolism in developing maize leaves
C4 plants, such as maize, concentrate carbon dioxide in a specialized
compartment surrounding the veins of their leaves to improve the efficiency of
carbon dioxide assimilation. Nonlinear relationships between carbon dioxide and
oxygen levels and reaction rates are key to their physiology but cannot be
handled with standard techniques of constraint-based metabolic modeling. We
demonstrate that incorporating these relationships as constraints on reaction
rates and solving the resulting nonlinear optimization problem yields realistic
predictions of the response of C4 systems to environmental and biochemical
perturbations. Using a new genome-scale reconstruction of maize metabolism, we
build an 18000-reaction, nonlinearly constrained model describing mesophyll and
bundle sheath cells in 15 segments of the developing maize leaf, interacting
via metabolite exchange, and use RNA-seq and enzyme activity measurements to
predict spatial variation in metabolic state by a novel method that optimizes
correlation between fluxes and expression data. Though such correlations are
known to be weak in general, here the predicted fluxes achieve high correlation
with the data, successfully capture the experimentally observed base-to-tip
transition between carbon-importing tissue and carbon-exporting tissue, and
include a nonzero growth rate, in contrast to prior results from similar
methods in other systems. We suggest that developmental gradients may be
particularly suited to the inference of metabolic fluxes from expression data.Comment: 57 pages, 14 figures; submitted to PLoS Computational Biology; source
code available at http://github.com/ebogart/fluxtools and
http://github.com/ebogart/multiscale_c4_sourc
A web-based teaching/learning environment to support collaborative knowledge construction in design
A web-based application has been developed as part of a recently completed research which proposed a conceptual framework to collect, analyze and compare different design experiences and to construct structured representations of the emerging knowledge in digital architectural design. The paper introduces the theoretical and practical development of this application as a teaching/learning environment which has significantly contributed to the development and testing of the ideas developed throughout the research. Later in the paper, the application of BLIP in two experimental (design) workshops is reported and evaluated according to the extent to which the application facilitates generation, modification and utilization of design knowledge
Immigrant Integration in Los Angeles: Strategic Directions for Funders
Provides an overview of the immigrant population; their contributions and challenges; the need for leadership development and other efforts to support their economic mobility, civic participation, and integration; and strategies for funding such efforts
Resting vs. active: a meta-analysis of the intra- and inter-specific associations between minimum, sustained, and maximum metabolic rates in vertebrates
Variation in aerobic capacity has far reaching consequences for the physiology, ecology, and evolution of vertebrates. Whether at rest or active, animals are constrained to operate within the energetic bounds determined by their minimum (minMR) and sustained or maximum metabolic rates (upperMR). MinMR and upperMR can differ considerably among individuals and species but are often presumed to be mechanistically linked to one another. Specifically, minMR is thought to reflect the idling cost of the machinery needed to support upperMR. However, previous analyses based on limited datasets have come to conflicting conclusions regarding the generality and strength of their association.
Here we conduct the first comprehensive assessment of their relationship, based on a large number of published estimates of both the intra-specific (n = 176) and inter-specific (n = 41) phenotypic correlations between minMR and upperMR, estimated as either exercise-induced maximum metabolic rate (VO2max), cold-induced summit metabolic rate (Msum), or daily energy expenditure (DEE).
Our meta-analysis shows that there is a general positive association between minMR and upperMR that is shared among vertebrate taxonomic classes. However, there was stronger evidence for intra-specific correlations between minMR and Msum and between minMR and DEE than there was for a correlation between minMR and VO2max across different taxa. As expected, inter-specific correlation estimates were consistently higher than intra-specific estimates across all traits and vertebrate classes.
An interesting exception to this general trend was observed in mammals, which contrast with birds and exhibit no correlation between minMR and Msum. We speculate that this is due to the evolution and recruitment of brown fat as a thermogenic tissue, which illustrates how some species and lineages might circumvent this seemingly general association.
We conclude that, in spite of some variability across taxa and traits, the contention that minMR and upperMR are positively correlated generally holds true both within and across vertebrate species. Ecological and comparative studies should therefore take into consideration the possibility that variation in any one of these traits might partly reflect correlated responses to selection on other metabolic parameters
Psychosocial mediators of change in physical activity in the Welsh national exercise referral scheme: secondary analysis of a randomised controlled trial
Objective:
While an increasing number of randomised controlled trials report impacts of exercise referral schemes (ERS) on physical activity, few have investigated the mechanisms through which increases in physical activity are produced. This study examines whether a National Exercise Referral Scheme (NERS) in Wales is associated with improvements in autonomous motivation, self-efficacy and social support, and whether change in physical activity is mediated by change in these psychosocial processes.<p></p>
Methods:
A pragmatic randomised controlled trial of NERS across 12 LHBs in Wales. Questionnaires measured demographic data and physical activity at baseline. Participants (N = 2160) with depression, anxiety or CHD risk factors were referred by health professionals and randomly assigned to control or intervention. At six months psychological process measures were collected by questionnaire. At 12 months physical activity was assessed by 7 Day PAR telephone interview. Regressions tested intervention effects on psychosocial variables, physical activity before and after adjusting for mediators and socio demographic patterning.<p></p>
Results:
Significant intervention effects were found for autonomous motivation and social support for exercise at 6 months. No intervention effect was observed for self-efficacy. The data are consistent with a hypothesis of partial mediation of the intervention effect by autonomous motivation. Analysis of moderators showed significant improvements in relative autonomy in all subgroups. The greatest improvements in autonomous motivation were observed among patients who were least active at baseline.<p></p>
Discussion:
The present study offered key insights into psychosocial processes of change in an exercise referral scheme, with effects on physical activity mediated by autonomous motivation. Findings support the use of self-determination theory as a framework for ERS. Further research is required to explain socio-demographic patterning in responses to ERS, with changes in motivation occurring among all sub-groups of participants, though not always leading to higher adherence or behavioural change. This highlights the importance of socio-ecological approaches to developing and evaluating behaviour change interventions, which consider factors beyond the individual, including conditions in which improved motivation does or does not produce behavioural change
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