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Broad Patterns (broad + pattern)
Selected AbstractsA test of the community conditioning hypothesis: Persistence of effects in model ecological structures dosed with the jet fuel jp-8ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000Wayne G. Landis Abstract The foundation of the community conditioning hypothesis, the persistence of effects, was tested in a series of microcosm experiments. Experiments were conducted with the water-soluble fraction of the turbine fuel JP-8 using the standard protocols for the standardized aquatic microcosm (SAM). A repeat trial was conducted using the SAM protocol but with a 126-d test period, twice the standard duration. The results were examined using a variety of conventional univariate, multivariate, and graphical techniques. The principal conclusions were as follows. Effects are persistent in these model ecological systems long after the degradation of the toxicant. Patterns of impacts are detectable at concentrations 15 times lower than an experimentally derived single-species EC50. The replicate experiments are not replicable in the specific, but the broad pattern of the disruption of algal- herbivore dynamics followed by more subtle effects are consistently repeated. The durability of the indirect effects and therefore the information about historical events appears to be a consistent feature of these microcosm systems. The identity of the treatment groups persists. The critical features of the community conditioning hypothesis,persistence of information within ecologicalsystems and the reappearance of patterns and therefore the nonequilibrium dynamics,are again confirmed. The implications of these findings for environmental toxicology, monitoring, and ecological risk assessment are discussed. [source] Sex- and region-specific alterations of basal amino acid and monoamine metabolism in the brain of aquaporin-4 knockout miceJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2005Yi Fan Abstract Aquaporin-4 (AQP4), a predominant water channel of the brain, mediates transmembrane water movement at the blood,brain barrier and brain,cerebrospinal fluid interface. A broad pattern of evidence indicates that AQP4 and regulators of its expression are potential targets for treatment of brain swelling, but whether it participates in the regulation of neurotransmission has not been reported. We examined neurochemical differences between AQP4-knockout and wild-type mice with particular focus on neurotransmission. Basal tissue neurotransmitter and metabolite levels were measured by high-performance liquid chromatography. Significant sex- and region-specific differences of amino acids and monoamines were found in the brain of wild-type and AQP4-knockout mice. In cortex, striatum, and hippocampus of male AQP4-knockout mice, an increase of glutamine and decrease of aspartate were observed. Glutamate was increased only in female AQP4-knockout mice. The lack of AQP4 failed to affect the levels of ,-aminobutyric acid and taurine. In the medial prefrontal cortex of AQP4-knockout mice, the levels of serotonin and norepinephrine were increased, but no significant change in dopamine level was found. In the striatum of male AQP4-knockout mice, the levels of dopamine and serotonin were remarkably increased, which was not found in female mice. In the hypothalamus of AQP4-knockout mice, only the serotonin level was altered. These results provide the first evidence that the lack of AQP4 expression is accompanied by sex- and region-specific alterations in brain amino acid and monoamine metabolism. © 2005 Wiley-Liss, Inc. [source] Is There a Dark Side to Government Supportfor Nonprofits?PUBLIC ADMINISTRATION REVIEW, Issue 3 2000Arthur C. Brooks The relationship between government social spending and private donations to the nonprofit sector is an issue that is relevant to both public administrators and nonprofit managers. Does government funding displace philanthropy, or encourage it? This article introduces the debate into the public administration literature. First, I survey and interpret the empirical work performed to date in this area by economists. Second, I retest this question across four nonprofit subsectors using data on both federal and state/local spending. My survey of the literature shows mixed results, although a broad pattern indicates that "crowding out" tends to dominate, particularly in the areas of social service provision and health. My empirical results are consistent with these findings, although they must be interpreted cautiously from a policy perspective: While results are statistically significant, the degree of crowding out is generally small. On the other hand, the claim that government funding stimulates giving seems to lack both statistical and policy significance. [source] The lifespan and life-cycle of self-help groups: a retrospective study of groups in Nottingham, UKHEALTH & SOCIAL CARE IN THE COMMUNITY, Issue 4 2010Sarah Chaudhary LLB (Hons) MA Abstract This article is based on an analysis of a practice database held by Self Help Nottingham, an organisation that supports local self-help groups. The database contains details of 936 groups that closed between 1982 and 2007. The aim of the study is to provide qualitative and descriptive quantitative information about the life-cycles of self-help groups, the problems that they face throughout their existence and the likelihood of different problems leading to their closure. The database was not collated for research purposes and so we restrict our discussion of the findings to identification of broad patterns regarding the birth and closure rates of different types of group and questions for future research. Comparisons were made between groups that addressed different types of problem, groups with different memberships and groups that had reached different stages in their existence. There was reasonable consistency in the survival rates of different types of group with physical health groups being the most likely to reach maturity followed by mental health and lastly social issue groups. Survival rates for groups that serve different membership populations were reasonably constant although there were some anomalies. There were high levels of consistency regarding the reasons for closure for groups closing at different stages of maturity. The most commonly cited reasons among all groups were the withdrawal of a ,key' member and a decline in membership. The article suggests that some of the assumptions and prescriptions within the existing literature need to be considered in light of more detailed empirical evidence, and it raises questions about the theoretical understanding of self-help groups. [source] Breeding latitude and timing of spring migration in songbirds crossing the Gulf of MexicoJOURNAL OF AVIAN BIOLOGY, Issue 3 2009Kathryn M. Langin Each spring, millions of songbirds migrate across the Gulf of Mexico on their way to breeding sites in North America. Data from radar and migration monitoring stations have revealed broad patterns in the spatial and temporal course of trans-Gulf migration. Unfortunately, we have limited information on where these birds have previously spent the winter and where they are migrating to breed. Here we measure stable-hydrogen isotopes in feathers (,Df) to infer the breeding latitude of five species of songbirds , hooded warblers Wilsonia citrina, American redstarts Setophaga ruticilla, black-and-white warblers Mniotilta varia, ovenbirds Seiurus aurocapilla, and northern waterthrushes S. noveboracensis, that were captured at a stopover site along the coast of southwestern Louisiana in spring 2004. Values of ,Df across all species ranged from ,163 to ,35, (n=212), and within most species the range was consistent with the latitudinal extent of known breeding sites in central and eastern North America. Individuals that arrived first along the northern Gulf coast had ,Df values indicative of southerly breeding sites in hooded warblers, American redstarts, black-and-white warblers, and ovenbirds, but no relationship was found between passage timing and ,Df for northern waterthrushes. Our findings suggest that spring passage is often timed to coincide with the emergence of suitable conditions on breeding areas, with southern breeding birds migrating first. [source] Representing species in reserves from patterns of assemblage diversityJOURNAL OF BIOGEOGRAPHY, Issue 7 2004M. B. Araújo Abstract Aim, A positive relationship between assemblage diversity (AD) , equivalent to the biotic version of the environment diversity, ED, method , and species diversity has been reported. This being true, reserve networks with many different assemblages would be expected to represent more species than reserve networks including fewer and less different assemblages. This idea was tested using European species atlas distributions of terrestrial vertebrates and plants. It is asked whether: (1) maximizing AD within one group would represent species diversity of this group better than expected by chance; and (2) maximizing AD within one group would represent species diversity of other groups better than expected by chance. Location, Europe. Methods, Three ordination techniques (non-metric multidimensional scaling, detrended correspondence analysis and correspondence analysis) are used to summarize patterns of compositional turnover within assemblages. p -Median location-allocation models are then calculated from ordination space to measure the degree of expected species representation within the group being sampled as well as the expected representation within other groups. Results are compared with near-optimal solutions obtained with complementarity-based algorithms and to a null model obtained by simulating selection of areas at random. Matrix correlation analysis was also performed to investigate broad patterns of covariation in compositional turnover of assemblages of species belonging to different taxonomic groups and these values were compared with correlation in species richness scores between groups. Results, The AD model did not always represent more species of the group being sampled than expected by chance (P < 0.05). Results were independent of the method and taxonomic group considered. Effectiveness of AD within one group to represent species of other groups varied, but in most cases it was worse than using complementarity-based algorithms as a surrogate strategy. Even when correlations indicated high coincidence between assemblages, taxonomic-based surrogates did not always recover more species than expected by chance (P < 0.05). Main conclusions, Results are discussed in the light of two possible explanations: (1) the AD model is based on unrealistic assumptions, namely that species have equal probability of having the centre of their distributions anywhere in ordination space and that species display unimodal, symmetrical, bell-shaped response curves to gradients; (2) particular implementation of methods may be inadequate to summarize useful complementarity among assemblages, especially for restricted-range species. We conclude that both arguments are likely to play a role in explaining results, but that opportunities exist to improve performance of existing surrogate strategies. [source] Culture and Women's SexualitiesJOURNAL OF SOCIAL ISSUES, Issue 2 2000Evelyn Blackwood Anthropological studies of women's same-sex relations in non-Western societies provide an important source for theorizing women's sexuality because they allow us to go beyond a narrow focus on Western cultures and concepts. Looking at studies from groups other than the dominant societies of Europe and America, I explore the diversity of women's sexualities and the sociocultural factors that produce sexual beliefs and practices. This article argues that sexual practices take their meaning from particular cultures and their beliefs about the self and the world. Cultural systems of gender, in particular, construct different sexual beliefs and practices for men and women. I conclude the article by suggesting some broad patterns at work in the production of women's sexualities across cultures. [source] A political ecology of violence and territory in West KalimantanASIA PACIFIC VIEWPOINT, Issue 1 2008Nancy Lee Peluso Abstract: This paper uses a political ecology perspective to examine relationships between violence and territory in West Kalimantan, focusing on the violent incidents of 1996,1997 and 1967,1968. Besides a regional account, the paper examines some of the ways residents of one village were drawn into and chose to participate in violence. The author concludes that while regional analyses can identify broad patterns, local analyses enable a greater understanding of both variation and the processes by which ethnic categories are constructed through violence. [source] | |||||||||||||