65 resultados para nonorthogonal contrasts


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Fluxes of HCH isomers α- and γ-HCH dynamics were determined in four industrial U.K. rivers feeding the North Sea. Sampling was conducted weekly basis over a 2-year period. This was complemented by discrete studies of events where two hourly sampling periods were used to investigate the fine time scale dynamics of fluxes. Two intensively industrialized rivers had average isomer concentrations of ~20 ng L-1 for both isomers, while average concentrations in the two less industrialized rivers ranged between 1.5 and 5.0 ng L-1. α-HCH concentrations showed no strong temporal patterns on any river, which contrasts with γ-HCH levels that increased considerably during late summer/early autumn following sustained periods of low river flow. Sampling during high river flow events on rivers with differing HCH pollution histories both showed the same dynamics in HCH isomer concentrations. γ-HCH concentrations decreased 4-fold during events while α-HCH-concentrations stayed constant. The increases in γ-HCH concentrations under low flow conditions and the rapid dilution of this isomer during events indicate that γ-HCH has current inputs to these river systems. It was calculated that these four rivers export 30.8 kg yr-1 of γ-HCH and 14.8 kg yr-1 of α-HCH to the North Sea.

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This article draws on an institutional ethnographic inquiry into the work of paramedics and the institutional setting that organizes and coordinates their work processes. Drawing on over 200 hours of observations and over 100 interviews with paramedics (average length of 18 minutes) and other emergency medical personnel, this article explores the standard and not so standard work of paramedics as they assess and care for their patients on the front lines of emergency health services. More specifically, I focus on the multiplicity of interfacing social, demographic, locational, situational, and institutional factors that shape and organize the work of paramedics. In doing so, this article provides insights into how paramedics orient to the social context in which their work occurs and contrasts this actual work with how their work is institutionally reported and made visible; what gets counted institutionally is not necessarily the same as what counts for the paramedics. This article problematizes this demarcation between what is known institutionally and “systematic practices of ‘not knowing’” (DeVault, 2008, p. 290).

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Single component geochemical maps are the most basic representation of spatial elemental distributions and commonly used in environmental and exploration geochemistry. However, the compositional nature of geochemical data imposes several limitations on how the data should be presented. The problems relate to the constant sum problem (closure), and the inherently multivariate relative information conveyed by compositional data. Well known is, for instance, the tendency of all heavy metals to show lower values in soils with significant contributions of diluting elements (e.g., the quartz dilution effect); or the contrary effect, apparent enrichment in many elements due to removal of potassium during weathering. The validity of classical single component maps is thus investigated, and reasonable alternatives that honour the compositional character of geochemical concentrations are presented. The first recommended such method relies on knowledge-driven log-ratios, chosen to highlight certain geochemical relations or to filter known artefacts (e.g. dilution with SiO2 or volatiles). This is similar to the classical normalisation approach to a single element. The second approach uses the (so called) log-contrasts, that employ suitable statistical methods (such as classification techniques, regression analysis, principal component analysis, clustering of variables, etc.) to extract potentially interesting geochemical summaries. The caution from this work is that if a compositional approach is not used, it becomes difficult to guarantee that any identified pattern, trend or anomaly is not an artefact of the constant sum constraint. In summary the authors recommend a chain of enquiry that involves searching for the appropriate statistical method that can answer the required geological or geochemical question whilst maintaining the integrity of the compositional nature of the data. The required log-ratio transformations should be applied followed by the chosen statistical method. Interpreting the results may require a closer working relationship between statisticians, data analysts and geochemists.

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This paper revisits work on the socio-political amplification of risk, which predicts that those living in developing countries are exposed to greater risk than residents of developed nations. This prediction contrasts with the neoliberal expectation that market driven improvements in working conditions within industrialising/developing nations will lead to global convergence of hazard exposure levels. It also contradicts the assumption of risk society theorists that there will be an ubiquitous increase in risk exposure across the globe, which will primarily affect technically more advanced countries. Reviewing qualitative evidence on the impact of structural adjustment reforms in industrialising countries, the export of waste and hazardous waste recycling to these countries and new patterns of domestic industrialisation, the paper suggests that workers in industrialising countries continue to face far greater levels of hazard exposure than those of developed countries. This view is confirmed when a data set including 105 major multi-fatality industrial disasters from 1971 to 2000 is examined. The paper concludes that there is empirical support for the predictions of socio-political amplification of risk theory, which finds clear expression in the data in a consistent pattern of significantly greater fatality rates per industrial incident in industrialising/developing countries.

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Background
In dementia, advance care planning (ACP) of end-of-life issues may start as early as possible in view of the patient’s decreasing ability to participate in decision making. We aimed to assess whether practicing physicians in the Netherlands and the United Kingdom who provide most of the end-of-life care, differ in finding that ACP in dementia should start at diagnosis.

Methods
In a cross-sectional study, we surveyed 188 Dutch elderly care physicians who are on the staff of nursing homes and 133 general practitioners from Northern Ireland. We compared difference by country in the outcome (perception of ACP timing), rated on a 1–5 agreement scale. Regression analyses examined whether a country difference can be explained by contrasts in demographics, presence, exposure and role perceptions.

Results
There was wide variability in agreement with the initiation of ACP at dementia diagnosis, in particular in the UK but also in the Netherlands (60.8% agreed, 25.3% disagreed and 14.0% neither agreed, nor disagreed). Large differences in physician characteristics (Dutch physicians being more present, exposed and adopting a stronger role perception) hardly explained the modest country difference. The perception that the physician should take the initiative was independently associated with agreeing with ACP at diagnosis.

Conclusions
There is considerable ambiguity about initiating ACP in dementia at diagnosis among physicians practicing in two different European health care systems and caring for different patient populations. ACP strategies should accommodate not only variations in readiness to engage in ACP early among patient and families, but also among physicians.