78 research outputs found

    Minority Social Work Educators\u27 Perspective on Minority Issues in Higher Education

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    The data set utilized for this exploratory research was the result of a survey sent by the Commission on Minority Group Concerns to minority members of the Council on Social Work Education. Members who identified minority status on their Council on Social work membership form were mailed a survey in January of 1994. The intent of this qualitative inquiry was to offer the respondents the opportunity to express their concerns regarding minority issues in social work education and provide suggestions to improve services to the Council on Social Work Education. In response to the surveys, the commission will be able to address minority issues and share the faculty views with the Council on Social Work Education. The findings will benefit the profession of social work by providing a focus on areas that have a need for further study. Social workers, as a result, will be better able to meet the needs of minority populations

    Expedition Programme PS132

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    Schreiben in der Sozialen Arbeit Zwischen Macht, Verantwortung und Befreiung

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    Schreiben ist mächtig. Was geschrieben steht, kann schwerwiegende Konsequenzen für die Beschriebenen haben. Gleichzeitig ist Schreiben ein machtvolles Werkzeug der Erkenntnis und der Selbstbefreiung für die Schreibenden selbst. In einer Summer School befassten sich Bachelor-Studierende damit, was dies für das Schreiben in der Sozialen Arbeit bedeutet

    Mark-recapture Estimates of Survival in Populations of the Asp Viper, Vipera aspis aspis

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    We estimated th eannual survivorship of two populations of the asp viper, Vipera aspis aspis, by recapturing known dult individuals in the field over six and nine years respectively. The snakes at the two study sites in th eJura mountains of northwestern Switzerland were active between mid-March and mid-October. Vispera a. aspis is easily captured by hand, has individually recognizable marks and is, therefore, well suited for long-term mark-recapture studies. The maximum likelihood estimates of annual survivorship are about 0.75 in both populations. The probability that a snake will be recaptured in any given year is about 0.4 (habita A) and about 0.33 (habitat B). Sampling effort within a year had little effect on the probability of recapture. Our best estimate of annual survibval of 0.75 for the two habitats combined compares well with other previous estimates in viperids and in V. aspis in particular. We found no detectable differences in the survival rates between sexes even when the two habitats were combined. We found weak evidence that there was a difference in the recapture probability between the sexes. The minimal adequate model for the combined data set suggested that there is a higher probability of recapturing surviving females (0.545) than males (0.331)

    Halocarbon emissions by selected tropical seaweeds: species-specific and compound-specific responses under changing pH

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    Five tropical seaweeds, Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, Padina australis Hauck, Sargassum binderi Sonder ex J. Agardh (syn. S. aquifolium (Turner) C. Agardh), Sargassum siliquosum J. Agardh and Turbinaria conoides (J. Agardh) Kützing, were incubated in seawater of pH 8.0, 7.8 (ambient), 7.6, 7.4 and 7.2, to study the effects of changing seawater pH on halocarbon emissions. Eight halocarbon species known to be emitted by seaweeds were investigated: bromoform (CHBr3), dibro-momethane (CH2Br2), iodomethane (CH3I), diiodomethane (CH2I2), bromoiodomethane (CH2BrI), bromochlorometh-ane (CH2BrCl), bromodichloromethane (CHBrCl2), and dibro-mochloromethane (CHBr2Cl). These very short-lived halocarbon gases are believed to contribute to stratospheric halogen concentrations if released in the tropics. It was observed that the seaweeds emit all eight halocarbons assayed, with the exception of K. alvarezii and S. binderi for CH2I2 and CH3I respectively, which were not measurable at the achievable limit of detection. The effect of pH on halocarbon emission by the seaweeds was shown to be species-specific and compound specific. The highest percentage changes in emissions for the halocarbons of interest were observed at the lower pH levels of 7.2 and 7.4 especially in Padina australis and Sargassum spp., showing that lower seawater pH causes elevated emissions of some halocarbon compounds. In general the seaweed least affected by pH change in terms of types of halocarbon emission, was P. australis. The commercially farmed seaweed K. alvarezii was very sensitive to pH change as shown by the high increases in most of the compounds in all pH levels relative to ambient. In terms of percentage decrease in maximum quantum yield of photosynthesis (Fv∕Fm) prior to and after incubation, there were no significant correlations with the various pH levels tested for all seaweeds. The correlation between percentage decrease in the maximum quantum yield of photosynthesis (Fv∕Fm) and halocarbon emission rates, was significant only for CH2BrCl emission by P. australis (r = 0.47; p ≤ 0.04), implying that photosynthesis may not be closely linked to halocarbon emissions by the seaweeds studied. Bromine was the largest contributor to the total mass of halogen emitted for all the seaweeds at all pH. The highest total amount of bromine emitted by K. alvarezii (an average of 98% of total mass of halogens) and the increase in the total amount of chlorine with decreasing seawater pH fuels concern for the expanding seaweed farming activities in the ASEAN region

    The diversity of population responses to environmental change

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    This is the final version. Available from Wiley via the DOI in this record.Data available from the Dryad Digital Repository: https:// doi.org/10.5061/dryad.d5f54s7The current extinction and climate change crises pressure us to predict population dynamics with ever-greater accuracy. Although predictions rest on the well-advanced theory of age-structured populations, two key issues remain poorly explored. Specifically, how the age-dependency in demographic rates and the year-to-year interactions between survival and fecundity affect stochastic population growth rates. We use inference, simulations and mathematical derivations to explore how environmental perturbations determine population growth rates for populations with different age-specific demographic rates and when ages are reduced to stages. We find that stage- vs. age-based models can produce markedly divergent stochastic population growth rates. The differences are most pronounced when there are survival-fecundity-trade-offs, which reduce the variance in the population growth rate. Finally, the expected value and variance of the stochastic growth rates of populations with different age-specific demographic rates can diverge to the extent that, while some populations may thrive, others will inevitably go extinct.Max Planck Society, Marie Curie FellowshipERCGerman Research FoundationSwiss National Science FoundationNational Science FoundationNational Institute of AgingRamon y Cajal Research GrantWenner-Gren FoundationLeakey FoundationNational Geographic SocietyZoological Society of San DiegoUniversity of PennsylvaniaArgentinean National Council of Researc

    Weak interpolation in Banach spaces

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    1. Trait-based approaches predict ecosystem functioning under environmental change by relating traits predicting changes in species densities (response traits) to traits driving ecosystem functioning (effect traits). Stressors can however affect ecosystem functioning not only by altering species densities, but also by directly changing species effect traits. 2. We first identified the response traits predicting the cell density of 18 marine benthic diatom strains along gradients of two chemical stressors (a pesticide and a metal, atrazine and copper). We then tested if response traits could predict stressor-induced changes in ecosystem functioning, i.e. changes in the effect traits driving the diatoms’ potential contribution to primary production, sediment stabilization and energy content in intertidal systems. Finally, we examined if changes in density and changes in ecosystem functioning were correlated, to assess whether species capable of growing under stressful conditions could maintain their contribution to ecosystem functioning. 3. The relationship between response traits and stressor-induced changes in density and ecosystem functioning was different depending on stressor type: a set of intercorrelated morphological traits predicted changes in both density and ecosystem functioning under metal stress, with large cells being more stress-resistant. Changes in density and changes in ecosystem functioning were positively related: diatoms whose density was least affected by the metal were also able to sustain functioning under metal exposure. 4. In contrast, the capacity for mixotrophic growth predicted changes in density, but not changes in ecosystem functioning under pesticide stress. Pesticide effects on density and on ecosystem functioning were negatively related for energy content and sediment stabilization, indicating a limited capacity of pesticide-tolerant diatoms to maintain their contribution to ecosystem functioning. Synthesis. Ecosystem functioning under stress can depend on whether response traits driving changes in density also predict direct stress effects on the species’ contribution to ecosystem functioning. Based on our results, we expect a disproportionate loss of functioning when traits driving species densities do not allow to maintain ecosystem functioning under stress

    Light and brominating activity in two species of marine diatom

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    Marine organisms mediate the formation of volatile inorganic (e.g. HOBr) and organic halogens (e.g. CHBr3) and contribute to the sea-to-air emission of bromine and iodine. This air-sea halogen exchange has implications for atmospheric chemistry. It is important to establish the physiological function of halogen metabolism in key groups of marine organisms to permit predictive model development. In this study a series of laboratory experiments was performed to investigate the link between the availability of photosynthetically active radiation (PAR) and brominating activity, as measured by the bromination of phenol red, in two cold-water marine diatoms (Thalassiosira antarctica, CCAP 1085/25; Porosira glacialis, CCMP 668). Brominating activity in T. antarctica was found to change in response to short term changes in photon flux density and to have a strong positive linear relationship with gross photosynthetic rate up to 260 µmol O2 (mg chla)-1 hr-1. Experiments performed across multiple diel cycles showed that light-phase brominating activities in T. antarctica were a factor of 2.8 (±1.0) higher than those measured in the dark. Whilst P. glacialis showed no response to short term changes in PFD, measurements across a number of diel cycles revealed that light-phase brominating activities in this diatom were significantly higher than those in the dark by a factor of 1.3 (±0.3). The addition of 0.1 µM H2O2 to the medium of T. antarctica cultures led to a significant increase in brominating activity by a factor of 2.4 (±0.3) relative to no-addition controls but no such response was seen in P. glacialis. These results suggest that there is a link between PAR light availability and brominating activity in marine diatoms but that the nature of this relationship differs between species. By establishing a potential link with common ecosystem model state variables (light and photosynthesis) this work provides the first step towards developing a predictive capability for brominating activity in the marine environment. More work is needed to assess the potential for developing generalised parameterisations between PAR light availability and brominating activity in diatom species representative of a wider range of ocean regions
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