Geostatistical analysis of hydraulic conductivity related data based on core samples from a heterogeneous fluvial aquifer

Summary This paper presents a case study for the geostatistical characterization of the hydraulic conductivity field of a fluvial aquifer. An experimental distribution of hydraulic conductivity values was obtained from core samples, which were analysed in the laboratory with regard to their grain size distribution. The geostatistical analysis was performed on (i) hydraulic conductivity data derived from the grain size distributions applying an empirical relationship, (ii) binary transforms of the hydraulic conductivity data using thresholds, and (iii) categorical variables obtained by a K-means clustering of the grain size distributions. Although the available data base is rather small, the results show that the investigated aquifer is distinctly heterogeneous and anisotropic with respect to hydraulic conductivity and soil texture.     

Editorial

Ohne Zusammenfassung

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Editorial

     

Soziologie der Gleichgewichtsökonomie

In particular industries, primarily Information- and Communications Technology and theCreative Industries, there has been a development away from the standard working model towards atypical work and increased self-employed work. The new work arrangements are characterized by more freedom, flexibility and autonomy, but also by new problems, different from the ones of standard work. As a reaction to the new work order new forms of shared offices have been emerging in different countries all around the world during the past years. For my diploma thesis I conducted an empirical study about this phenomena. My essential hypothesis is, that Coworking Spaces can be seen as a spatial manifestation of new work arrangements and the ways people approach them. This article is about requirements and demands that are fundamental for the emergence of Coworking Spaces, as well as the possibilities to support users in their individual work lives.     

Estimation of Unit Risk for Coke Oven Emissions

In 1984, based on epidemiological data on cohorts of coke oven workers, USEPA estimated a unit risk for lung cancer associated with continuous exposure from birth to 1 pg/m3 of coke oven emissions, of 6.2 × This risk assessment was based on information on the cohorts available through 1966. Follow-up of these cohorts has now been extended to 1982 and, moreover, individual job histories, which were not available in 1984, have been constructed. In this study, lung cancer mortality in these cohorts of coke oven workers with extended follow-up was analyzed using standard techniques of survival analysis and a new approach based on the two stage clonal expansion model of carcinogenesis. The latter approach allows the explicit consideration of detailed patterns of exposure of each individual in the cohort. The analyses used the extended follow-up data through 1982 and the detailed job histories now available. Based on these analyses, the best estimate of unit risk is 1.5 × with 95% confidence interval = 1.2 × 10-"1.8 X     

Quantitative Assessment of the Risk of Lung Cancer Associated with Occupational Exposure to Refractory Ceramic Fibers

We present the results of a quantitative assessment of the lung cancer risk associated with occupational exposure to refractory ceramic fibers (RCF). The primary sources of data for our risk assessment were two long-term oncogenicity studies in male Fischer rats conducted to assess the potential pathogenic effects associated with prolonged inhalation of RCF. An interesting feature of the data was the availability of the temporal profile of fiber burden in the lungs of experimental animals. Because of this information, we were able to conduct both exposure–response and dose–response analyses. Our risk assessment was conducted within the framework of a biologically based model for carcinogenesis, the two-stage clonal expansion model, which allows for the explicit incorporation of the concepts of initiation and promotion in the analyses. We found that a model positing that RCF was an initiator had the highest likelihood. We proposed an approach based on biological considerations for the extrapolation of risk to humans. This approach requires estimation of human lung burdens for specific exposure scenarios, which we did by using an extension of a model due to Yu. Our approach acknowledges that the risk associated with exposure to RCF depends on exposure to other lung carcinogens. We present estimates of risk in two populations: (1) a population of nonsmokers and (2) an occupational cohort of steelworkers not exposed to coke oven emissions, a mixed population that includes both smokers and nonsmokers.     

MMCTest—A Safe Algorithm for Implementing Multiple Monte Carlo Tests

Consider testing multiple hypotheses using tests that can only be evaluated by simulation, such as permutation tests or bootstrap tests. This article introduces MMCTest , a sequential algorithm that gives, with arbitrarily high probability, the same classification as a specific multiple testing procedure applied to ideal p‐values. The method can be used with a class of multiple testing procedures that include the Benjamini and Hochberg false discovery rate procedure and the Bonferroni correction controlling the familywise error rate. One of the key features of the algorithm is that it stops sampling for all the hypotheses that can already be decided as being rejected or non‐rejected. MMCTest can be interrupted at any stage and then returns three sets of hypotheses: the rejected, the non‐rejected and the undecided hypotheses. A simulation study motivated by actual biological data shows that MMCTest is usable in practice and that, despite the additional guarantee, it can be computationally more efficient than other methods.     

The Politics of Public and Private Pension Generosity in Advanced Democracies

The quantitative strand of social policy research suffers from a triple deficit: analyses of aggregate expenditure dominate, most of the few studies of replacement rates focus on unemployment or sickness benefits while pensions are excluded, and the interdependence between public and private pension plans is often ignored. This article addresses the said deficits, first, by discussing the pension sectors' theoretical peculiarities and by proposing two hypotheses: one on the role played by political parties in implementing public pension retrenchment, and the second on their role in extending private pension plans. Second, the article presents regression results of public pension replacement rate changes in 18 developed democracies. The findings show considerably smaller cuts to pensions than to unemployment or sickness benefits, and striking differences regarding partisan effects between the sectors. Lastly, the article assesses partisan effects on private pension plans, detecting some rather surprising effects. Most noteworthy is the fact that those parties which reduced public pension generosity during the 1990s (i.e. Social Democrats) cannot claim responsibility for compensating these cuts by eliciting higher private engagement.     

For the Love of Art? Episodic Volunteering at Cultural Events

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Although episodic volunteering is a popular form of volunteering and has received increasing attention from researchers,...