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61.
Soil microbial biomass (MB) facilitates key ecosystem functions such as soil aggregation and nutrient cycling and makes a substantial contribution to soil organic matter. While agricultural conversion drastically reduces MB, the use of organic amendments is an effective way to rebuild depleted MB. Yet, little is known about broad-scale, global controls over MB responses to organic inputs. We used a meta-analysis to identify the degree to which soil properties, agricultural management, and geographic location regulate MB response (carbon, Cmic; nitrogen, Nmic; and C:N ratio, C:Nmic) to animal manure-based inputs relative to inorganic fertilizers. We show that organic amendments increased Cmic by 36% and Nmic by 27% across all observations. The chemistry of amendments and their application rates were the strongest regulators of Cmic but edaphic properties were also important. C:Nmic averaged 8.6 and was not influenced by organic amendments under any conditions, providing evidence that the physiological requirements of microbes, rather than management or environmental factors, constrain their elemental stoichiometry. Our study indicates that even small quantities of organic amendments can be used to rapidly restore MB across a range of cropping systems but specific responses depend upon the type and rate of inputs as well soil characteristics.  相似文献   
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63.
经过近4年时间的准备之后,非洲即将开始一个创新的举措.非洲库存计划(ASP)是一个涉及非洲国家、国际机构、非政府组织、私营部门CropLife国际(CLI)和区域性团体的多风险承担者伙伴关系.非洲库存计划的目标是雄心勃勃的:在下一个10年到15年清理和处理整个非洲现有的库存农药,并帮助防止未来的农药积累,总成本约为2.5-3.0亿美元.幸亏有全球环境机构(GEF)的2500万美元的基本支持以及捐献国政府的共筹资金,在15个国家的第一阶段活动资金已经增加到5000多万美元.然而第一阶段的工作和第二阶段计划仍然需要另外的2000万美元资金.  相似文献   
64.
Content analysis of newspaper coverage of the Florida panther   总被引:1,自引:0,他引:1  
Populations of large carnivores are declining globally, and analysis of public discourse about carnivores is useful for understanding public opinion and influences on management and policy. Portrayal of carnivores in the media affects public perceptions and support for their conservation. We conducted a content analysis of 513 articles about Florida panthers (Puma concolor coryi) published from 2003 to 2006 in newspapers with local circulation in core panther habitat in southwest Florida and papers with statewide circulation to compare the differences in the amount of coverage and portrayals of panther risks to people and property on the basis of proximity of human communities to panthers. Local papers published significantly more news articles and significantly longer news articles primarily about panthers. Articles in local and statewide papers used both episodic frames, which focus on specific occurrences (e.g., a panther sighting or predation) and thematic frames, which focus on general trends (e.g., abundance of panthers over time). Local articles more often emphasized risks that panthers might harm people, pets, or livestock than statewide papers. Our results are consistent with theory that proximity to human-carnivore conflict influences perceptions and salience of risks posed by large carnivores. Most articles mentioned panthers as a secondary topic, which we believe was a result of the relevance an endangered carnivore has in discussions of public land management, development, and regulations in Florida. Claims made by sources quoted in each article had a neutral to positive depiction of panthers, and most quotations were from federal and state agency scientists. We suggest continued use by the media of agency sources provides the opportunity for clear, concordant messages about panther management. Content analysis provides a way to monitor media portrayal of carnivores for consistency with agency outreach goals.  相似文献   
65.
ABSTRACT: :The model described herein was used to assess effects of the Suwannee River sill (a low earthen dam constructed to impound the Suwannee River within the Okefenokee National Wildlife Refuge to eliminate wildfires) on the hydrologic environment of Okefenokee Swamp, Georgia. Developed with Arc/Info Macro Language routines in the GRID environment, the model distributes water in the swamp landscape using precipitation, inflow, evapotranspiration, outflow, and standing water. Water movement direction and rate are determined by the neighborhood topographic gradient, determined using survey grade Global Positioning Systems technology. Model data include flow rates from USGS monitored gauges, precipitation volumes and water levels measured within the swamp, and estimated evapotranspiration volumes spatially modified by vegetation type. Model output in semi‐monthly time steps includes water depth, water surface elevation above mean sea level, and movement direction and volume. Model simulations indicate the sill impoundment affects 18 percent of the swamp during high water conditions when wildfires are scarce and has minimal spatial effect (increasing hydroperiods in less than 5 percent of the swamp) during low water and drought conditions when fire occurrence is high but precipitation and inflow volumes are limited.  相似文献   
66.
This is the first report of prenatal diagnosis of a fetus with brachio-oto-renal dysplasia (BOR) syndrome with right-sided renal agenesis and severe left hypoplasia. The father of this fetus had malformed external ears, a left-sided preauricular pit and branchial cyst, and bilateral mild to moderate deafness without a demonstrable renal anomaly. This family highlights the variable expressivity seen in the autosomal dominant BOR syndrome, the importance of genetic counselling for families with BOR syndrome, and the aetiologic heterogeneity of renal agenesis.  相似文献   
67.
This paper reports the development of the Career–Family Attitudes Measure (CFAM), a new 56-item instrument for measuring individuals' attitudes towards managing the career and family interface. The measure was administered to a large sample of high school students and factor analyzed to reveal six dimensions of career and family attitudes, which were then scaled. Females in the sample had significantly more positive attitudes towards Balance and Independence than did males, while males had significantly more positive attitudes towards Dominance and Spousal Support than did females. Antecedents such as parental employment history and educational aspirations were significantly related to several of the scales. Results indicated that career–family attitudes involve preferences for the integration of career and family rather than for trade-offs between them. Research to establish the validity and explore the many applications of the CFAM is needed. © 1998 John Wiley & Sons, Ltd.  相似文献   
68.
INTRODUCTION: This longitudinal field study was designed to encourage Appalachian coal miners in West Virginia and Pennsylvania to engage in hearing-protection behaviors. METHOD: Participants were mailed postcards that featured either a positive, negative, or neutral message on the outside of the postcard and a message encouraging hearing protection behaviors on the inside. The first posttest measurement of the effectiveness of the persuasive messages was conducted about a week after the postcards were mailed. The delayed posttest measurement was conducted six weeks later. RESULTS: Responses from 307 coal miners revealed that the positive or neutral messages generated significantly more self-reported hearing protection behaviors than the negative message. Identical results were obtained in a delayed posttest assessment of miners' self-reported hearing protection behaviors. The positive message was also more effective than either the neutral or negative message in preventing defensive mechanisms from emerging over time. IMPACT ON INDUSTRY: Positive and neutral messages were convincingly more successful than negative messages in facilitating self-reported hearing protection behaviors among coal miners. Similarly, the positive messages kept defensive processes at bay.  相似文献   
69.
Levels and trends of brominated flame retardants in the Arctic   总被引:24,自引:0,他引:24  
de Wit CA  Alaee M  Muir DC 《Chemosphere》2006,64(2):209-233
Polybrominated diphenyl ethers (PBDEs) containing two to seven bromines are ubiquitous in Arctic biotic and abiotic samples (from zooplankton to polar bears (Ursus maritimus) and humans; air, soil, sediments). The fully brominated decabromodiphenyl ether (BDE-209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA) and polybrominated biphenyls (PBBs) are also present in biotic and abiotic samples. Spatial trends of PBDEs and HBCD in top predators are similar to those seen for polychlorinated biphenyls (PCBs) and indicate western Europe and eastern North America as source regions. Concentrations of tetra- to heptaBDEs have increased significantly in North American and Greenlandic Arctic biota and in Greenland freshwater sediments paralleling trends seen further south. For BDE-209, increasing concentrations in Greenlandic peregrine falcons (Falco peregrinus) and in dated lake sediment cores in the Canadian Arctic have been seen during the 1990s. BDE-47, -99, -100 and -153 are observed to biomagnify in Arctic food webs. summation operatorPBDE concentrations in Arctic samples are lower than in similar sample types from more southerly regions and are one or more orders of magnitude lower than summation operatorPCB concentrations except for some levels for air. Air and harbor sediment results for PBDEs indicate that there are local sources near highly populated areas within the Arctic. Findings of PBBs on moss and TBBPA on an air filter, and that both are found in biota at high trophic levels indicates that these compounds may also reach the Arctic by long-range atmospheric transport. Based on the evidence of their presence in the Arctic and indications that most if not all are undergoing long-range transport, these brominated flame retardants (BFRs) have characteristics that qualify them as POPs according to the Stockholm Convention.  相似文献   
70.
We studied the formation of four nitrogenous DBPs(N-DBPs) classes(haloacetonitriles,halonitromethanes, haloacetamides, and N-nitrosamines), as well as trihalomethanes and total organic halogen(TOX), after chlorination or chloramination of source waters. We also evaluated the relative and additive toxicity of N-DBPs and water treatment options for minimisation of N-DBPs. The formation of halonitromethanes, haloacetamides, and N-nitrosamines was higher after chloramination and positively correlated with dissolved organic nitrogen or total nitrogen. N-DBPs were major contributors to the toxicity of both chlorinated and chloraminated waters. The strong correlation between bromide concentration and the overall calculated DBP additive toxicity for both chlorinated and chloraminated source waters demonstrated that formation of brominated haloacetonitriles was the main contributor to toxicity. Ozone–biological activated carbon treatment was not effective in removing N-DBP precursors. The occurrence and formation of N-DBPs should be investigated on a case-by-case basis, especially where advanced water treatment processes are being considered to minimise their formation in drinking waters, and where chloramination is used for final disinfection.  相似文献   
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