A model of the antecedents of early union commitment: The role of socialization experiences and steward characteristics

The present study aimed at investigating the influence of shop steward characteristics and early union socialization experiences on new members' attitudes toward unions and their affective commitment to the union. Two thousand surveys were mailed to the most recent members of the National Association of Letter Carriers. Of these, 658 (33 per cent) were returned. Focusing on those individuals who had joined the union within the past 12 months yielded a usable sample of 585. A two-stage, structural equation modeling approach indicated a satisfactory goodness-of-fit for both the measurement and structural models. Individual socialization experiences significantly affected union attitudes. The latter variable was a significant predictor of union commitment. These results are discussed in the context of the organizational socialization literature and union commitment research.     

Occurrence of sulfonamide antimicrobials in private water wells in Washington County, Idaho, USA

Samples from six private wells formerly used as sources for drinking water by the residents of Washington County (Weiser, Idaho) were collected to assess the impact of a nearby confined animal feeding operation (CAFO) on the quality of the local groundwater. All six samples were found contaminated by two veterinary antimicrobials, sulfamethazine (at concentrations from 0.076 to 0.22 μg/l) and sulfadimethoxine (at concentrations from 0.046 to 0.068 μg/l). These groundwater samples also contained elevated concentrations of nitrate and ammonium. Three of the sampled wells have nitrate levels that exceeded the maximum contaminant level set by the US Environmental Protection Agency for drinking water, with nitrate concentration as high as 39.1 mg/l. All but one well showed nitrate, which instead contained ammonium at 1.22 mg/l. Analysis of the nitrate and ammonium in these samples by isotopic ratio mass spectrometry indicated δ¹⁵N characteristic of an animal or human waste source. Results from this study underscore the role of CAFO as an important source of antibiotic contamination of groundwater.     

Release of colloidal particles in natural porous media by monovalent and divalent cations

We study mobilization of colloidal particles from natural porous media, such as soils and groundwater aquifers. Extensive laboratory scale column experiments of particle release from four different subsurface materials are presented. The important characteristics of the release process are (i) its non-exponential kinetics, (ii) the finite supply of colloidal particles and (iii) the strong dependence of the release kinetic on the nature of the adsorbed cations. Particle release depends most sensitively on the relative saturation of the medium with divalent cations. We propose a mathematic model, which captures all these aspects quantitatively, and can be used to describe the coupling between transport of major cations and the release of colloidal particles. The present experimental investigations as well as the developed modeling framework represent an important step towards the understanding of colloid-facilitated transport phenomena in natural porous media.     

废弃电子设备的资源化研究发展现状

分析了废弃电子设备的主要特点、资源化回收与利用的不同方法及其优缺点，并详细介绍了废弃电子设备机械处理的研究及工业应用现状。     

Influence of CO<Subscript>2</Subscript> on the micro-structural properties of spider dragline silk: X-ray microdiffraction results

The mechanical properties of spider dragline fibres are altered by CO₂ exposure under anaesthetizing conditions during the spinning process. In order to relate these macroscopic changes to a microscopic model, the extrusion of dragline silk was studied by synchrotron radiation microdiffraction. A brief exposure of a female Nephila senigalensis spider to CO₂ results after an incubation time of less than 7 min in the extrusion of a thread (two fibres) swollen with water. The data are interpreted for a model of crystalline -sheet domains containing nanofibrils, which reinforce a network of protein chains. The protein network absorbs water, leaving the nanofibrils unaffected. A continuous flow of CO₂ results in a co-extrusion of a dragline thread and an isotropic silk fraction, which probably has a glycine-rich sequence. Long CO₂ exposure reduces the axial alignment of nanofibrils, presumably due to a partial destruction of the amorphous network.     

Exploring future agricultural development and biodiversity in Uganda,Rwanda and Burundi: a spatially explicit scenario-based assessment

Regional Environmental Change - Competition for land is increasing as a consequence of the growing demands for food and other commodities and the need to conserve biodiversity and ecosystem...     

Changes in the spatial patterns of human appropriation of net primary production (HANPP) in Europe 1990–2006

Understanding patterns, dynamics, and drivers of land use is crucial for improving our ability to cope with sustainability challenges. The human appropriation of net primary production (HANPP) framework provides a set of integrated socio-ecological indicators that quantify how land use alters energy flows in ecosystems via land conversions and biomass harvest. Thus, HANPP enables researchers to systematically and consistently assess the outcome of changes in land cover and land-use intensity across spatio-temporal scales. Yet, fine-scale HANPP assessments are so far missing, an information important to address site-specific ecological implications of land use. Here, we provide such an assessment for Europe at a 1-km scale for the years 1990, 2000, and 2006. The assessment was based on a consistent land-use/biomass flow dataset derived from statistical data, remote sensing maps, and a dynamic global vegetation model. We find that HANPP in Europe amounted to ~43 % of potential productivity, well above the global average of ~25 %, with little variation in the European average since 1990. HANPP was highest in Central Europe and lower in Northern and Southern Europe. At the regional level, distinct changes in land-use intensity were observed, most importantly the decline of cropland areas and yields following the breakdown of socialism in Eastern Europe and the subsequent recovery after 2000, or strong dynamics related to storm events that resulted in massive salvage loggings. In sum, however, these local dynamics cancelled each other out at the aggregate level. We conclude that this finding warrants further research into aspects of the scale-dependency of dynamics and stability of land use.     

Guidelines for Expert Witnesses

The legal gauntlet is remarkably visible in today’s technical society. Unfortunately, engineering and scientific personnel are often poorly prepared for trial-type proceedings. Consequently, experts not only need to know their respective fields, but how to be prepared as expert witnesses.