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11.
A. P. Lemes M. A. Soto-Oviedo W. R. Waldman L. H. Innocentini-Mei N. Durán 《Journal of Polymers and the Environment》2010,18(3):250-259
The effect of lignosulfonate on poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, was studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and
thermogravimetric analysis (TGA). The PHBV/lignosulfonate samples were prepared by melt mixing in an internal mixer. SEM showed
that PHBV/lignosulfonate samples present a cracked surface that is more intense in mixtures with high lignosulfonate proportions.
According to DSC, melting and glass transition temperatures of the PHBV matrix decrease with lignosulfonate addition. The
same effect was observed for melting enthalpies (ΔHm), which indicates a decrease of crystallinity. TGA showed that thermal stability of PHBV/lignosulfonate samples was shifted
to lower temperatures, which indicates the existence of an interaction between the thermal decomposition processes of PHBV
and lignosulfonate. 相似文献
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The international community has compelling humanitarian, political, security and economic reasons to engage in rebuilding and strengthening health systems in fragile states. Improvements in health services and systems help to strengthen civil society and to restore legitimacy to governments. Effective engagement with fragile states to inform the design of health programmes and selection of interventions depends on donor coordination and an understanding of health system challenges. Planning requires consideration of allocation (services to be delivered), production (organisation of services), distribution (beneficiaries of services) and financing. The criteria for selecting interventions are: their impact on major health problems; effectiveness; the possibility of scale-up; equity; and sustainability. There are various options for financing and models of engagement, but support should always combine short-term relief with longer-term development. Stakeholders should aim not only to save lives and protect health but also to bolster nations' ability to deliver good-quality services in the long run. 相似文献
14.
C.J. Watras K.A. Morrison J.L. Rubsam B. Rodger 《Atmospheric environment (Oxford, England : 1994)》2009,43(26):4070-4077
Total gaseous mercury (TGM) in the lower atmosphere of northern Wisconsin exhibits strong annual and diurnal cycles similar to those previously reported for other rural monitoring sites across mid-latitude North America. Annually, TGM was highest in late winter and then gradually declined until late summer. During 2002–04, the average TGM concentration was 1.4 ± 0.2 (SD) ng m?3, and the amplitude of the annual cycle was 0.4 ng m?3 (~30% of the long-term mean). The diurnal cycle was characterized by increasing TGM concentrations during the morning followed by decreases during the afternoon and night. The diurnal amplitude was variable but it was largest in spring and summer, when daily TGM oscillations of 20–40% were not uncommon. Notably, we also observed a diurnal cycle for TGM indoors in a room ventilated through an open window. Even though TGM concentrations were an order of magnitude higher indoors, (presumably due to historical practices within the building: e.g. latex paint, fluorescent lamps, thermometers), the diurnal cycle was remarkably similar to that observed outdoors. The indoor cycle was not directly attributable to human activity, the metabolic activity of vegetation or diurnal atmospheric dynamics; but it was related to changes in temperature and oxidants in outdoor air that infiltrated the room. Although there was an obvious difference in the proximal source of indoor and outdoor TGM, similarities in behavior suggest that common TGM cycles may be driven largely by adsorption/desorption reactions involving solid surfaces, such as leaves, snow, dust and walls. Such behavior would imply a short residence time for Hg in the lower atmosphere and intense recycling – consistent with the “ping-pong ball” or “multi-hop” conceptual models proposed by others. 相似文献
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Carl P. Maertz Jr Rodger W. Griffeth Nathanael S. Campbell David G. Allen 《组织行为杂志》2007,28(8):1059-1075
This study examines mediated effects of perceived supervisor support (PSS) and perceived organizational support (POS) on turnover cognitions, and their interactive effects on turnover behavior in a sample of 225 social services workers. In this study, we address a seeming contradiction in current findings regarding support and attachments to managers versus attachments to the organization itself. The POS literature suggests fully mediated causal paths to turnover from POS and PSS, through affective commitment. Whereas, the commitment, LMX, and turnover literatures suggest alternative causal paths that imply broader effects for POS and PSS on turnover. Contrary to earlier POS literature, findings showed that PSS had independent effects on turnover cognitions not mediated through POS. Model tests also indicated that POS had significant effects on turnover mediated through normative commitment, as well as affective organizational commitment. Moreover, a new significant interactive relationship was discovered such that low PSS strengthened the negative relationship between POS and turnover, while high PSS weakened it. Implications for research and practice are discussed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Waldman P. Lucas F. S. Varrault G. Moulin L. Wurtzer S. 《Food and environmental virology》2020,12(2):118-129
Food and Environmental Virology - In urban rivers, many of which are used for drinking water production, viruses encounter a range of particulate, colloidal, and dissolved organic and inorganic... 相似文献
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Organizational neuroscience has great promise for advancing organizational research and practice. The field, however, is developing rapidly and has also become the subject of technological and methodological challenges that must be considered when conducting or interpreting neuroscience research as applied to organizational behavior. We explore four issues we deem to be important in understanding the role of neuroscience in organizational behavior research: (i) neuroscientific research and reductionism; (ii) the need to address methodological and technological challenges in conducting this type of research; (iii) how neuroscientific research is meaningful in organizations (the “So what?” issue); and (iv) neuroscience as just another management fad. In addressing these issues, we hope to set out a roadmap that will enable organizational scholars to avoid past mistakes and thus serve to advance multidisciplinary research in organizational behavior using neuroscientific approaches. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
20.
Keith V. Slack Rodger F. Ferreira Robert C Averett 《Journal of the American Water Resources Association》1986,22(2):237-248
ABSTRACT: Four different bottom-placed artificial substrates were compared with the Ponar grab for collecting benthic invertebrates. Artificial substrate samples of organisms were larger and more diverse than those of the grab. Barbeque Basket samplers caught the most taxa and individuals and Beak Trays caught the least. Chironomids and crustaceans were dominant in artificial substrate samples. Exposure habitat (left or right bank) determined taxa availability, whereas sampler design determined suitability for colonization by the taxa. Diversity for Beak Tray samples was lower than that for other artificial substrates but higher than for Ponar samples. The Barbeque Basket, Bull Basket, and Multiple Plate samples were taxonomically similar. Ponar samples were different, and Beak Trays were of intermediate similarity. As qualitative samplers, Barbeque Baskets were 63 percent efficient, followed by Bull Baskets (55 percent), Multiple Plates (48 percent), Beak Trays (38 percent), and Ponar Grabs (6–10 percent). Bull Baskets required the least and Beak Trays the most replicates to be within a preselected percentage error of the mean at the 95 percent probability level for numbers of taxa and individuals, and for diversity. Under conditions of the study, Bull Baskets ranked highest, followed by Barbeque Baskets and Multiple Plates, in selected performance criteria. Differences between grab and artificial substrate samples are explainable in terms of major riverine habitats and characteristics of the collection methods. 相似文献