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Under current climate change scenarios, temperatures in Siberia are expected to increase, and consequently, fire is also expected to increase. Potential climate-induced change is difficult to assess in Siberia because ground-based fire data are not complete. This investigation introduces a method by which potential climate-induced change can be remotely evaluated. Mean fire return intervals are established for 58 ecosystems across Siberia using eight years of satellite-based area burned data (1995 to 2002). Mean fire return intervals should decrease under current climate change scenarios, however the results do not currently demonstrate consistent evidence of fire-induced change. The overall boreal forest mean fire return interval is lower than the published mean, inferring increased fire. Most notably, using satellite data to calculate mean fire return intervals in individual ecosystems for the entire population of fire is shown to be a viable method by which potential climate-induced land cover change can be evaluated.  相似文献   
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We report three cases of amniocentesis in which mosaicism for trisomy 12 was detected in two or more independent cultures. The parents elected to terminate the pregnancy in all three cases. Follow-up studies in two of the cases confirmed the mosaicism in fetal tissues (in subcutaneous tissue in one case; in fetal lung in the other), but not in blood. No fetal anomalies were evident by ultrasound or at autopsy. These results along with other reported cases demonstrate the difficulty in counselling for mosaic trisomy 12.  相似文献   
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The West-Gaeke method has been shown to be feasible for detecting changes in SO2 concentration greater than 10%. Reliable results can be obtained if one makes up stock solutions of the pararosaniline dye from the same powder batch at the same time. Gum arabic stabilizes the SOvtetrachloromercurate complex at concentrations of SO2 > 8 μg/ml.  相似文献   
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Cane sugar production by-products can be considered either as waste, affecting the environment, or as a resource when an appropriate valorization technology is implemented.This study is made with the objective of identifying and quantifying the aspects which have the largest environmental impact of four alternatives for using by-products and wastes from the cane sugar process and suggest improvements in the systems.For this analysis a cane sugar mill was chosen in Cuba and four alternatives were designed for the by-product valorization. The first alternative represents the conventional sugar production; its main characteristics are the use of synthetic fertilizers, pesticides, the bagasse combustion and the usage of molasses and agricultural wastes as animal food. Other wastes constitute emissions to the environment. Alternatives II, III and IV incorporate more use of by-products and wastes. Alternative II considers the use of wastewater, filter cake and ashes for the substitution of synthetic fertilizers. In Alternative III, the filter cake and wastewater are used for biogas production and Alternative IV integrates alcohol and biogas production into the sugar production process.The assessment is done by means of Life Cycle Assessment, according to the ISO 14040 series by using the SimaPro 6.0 LCA software, Ecoinvent database and the Eco-indicator 99 methodology. As a functional unit the daily sugar production of the mill was defined (216 t/d). The sugar was selected as main product and all the by-products were assumed to substitute other products on the market, avoided products.For the four alternatives, the agricultural stage shows the greatest impact due to land use, fuel and agrochemicals consumption. In the industrial stage, the electricity cogeneration with bagasse has the highest impact as to respiratory effects due to the emission of tiny particle material into the atmosphere. The major difference between the alternatives is found in the resource impact category. The advantage of producing alcohol, biogas, animal food and fertilizers from the by-products is made obvious through the comparative study for resource savings.  相似文献   
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An interaction effect indicates that a relationship is contingent upon the values of another (moderator) variable. Thus, interaction effects describe conditions under which relationships change in strength and/or direction. Understanding interaction effects is essential for the advancement of the organizational sciences because they highlight a theory's boundary conditions. We describe procedures for estimating and interpreting interaction effects using moderated multiple regression (MMR). We distill the technical literature for a general readership of organizational science researchers and include specific best‐practice recommendations regarding actions researchers can take before and after data collection to improve the accuracy of MMR‐based conclusions regarding interaction effects. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
69.
The West African Sahel is a harsh environment stressed by a fast-growing population and increasing pressure on the scarce natural resources. Agriculture is the main source of livelihood of the majority of the people living in the area. Increases in temperature and/or modifications in rainfall quantities and distribution will substantially impact on the natural resource on which agriculture depends. The vulnerability of livelihoods based on agriculture is increased and most likely exacerbate and accelerate the current ‘downward spiral’ of underdevelopment, poverty and environmental degradation. Notably, droughts, a short rainy season and/or very low rainfall will be felt by current systems. To cope with the difficult climatic situation, farm households have developed a range of strategies including selling of animals and on-farm diversification or specialization. At regional level, early warning systems including an operational agro-meteorological information system already provide farmers with crucial information. Substantial political, institutional and financial efforts at national and international level are indispensable for the sustenance of millions of lives. In terms of development, priority needs to be given to adaptation and implementation of comprehensive programs on water management and irrigation, desertification control, development of alternative sources of energy and the promotion of sustainable agricultural practices by farmers.  相似文献   
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