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Plants offer metabolically rich floral nectar to attract visiting pollinators. The composition of nectar includes not only sugars, but also amino acids. We have examined the amino acid content of the nectar of ornamental tobacco and found that it is extremely rich (2 mM) in proline. Because insect pollinators preferentially utilize proline during the initial phases of insect flight and can reportedly taste proline, we determined whether honeybees showed a preference for synthetic nectars rich in proline. We therefore established an insect preference test and found that honeybees indeed prefer nectars rich in the amino acid proline. To determine whether this was a general phenomenon, we also examined the nectars of two insect-pollinated wild perennial species of soybean. These species also showed high levels of proline in their nectars demonstrating that plants often produce proline-rich floral nectar. Because insects such as honeybees prefer proline-rich nectars, we hypothesize that some plants offer proline-rich nectars as a mechanism to attract visiting pollinators.  相似文献   
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Women, Health and Humanitarian Aid in Conflict   总被引:4,自引:0,他引:4  
The burden of political conflict on civilian populations has increased significantly over the last few decades. Increasingly, the provision of resources and services to these populations is coming under scrutiny; we highlight here the limited attention to gender in their provision. Women and men have different exposures to situations that affect health and access to health-care and have differential power to influence decisions regarding the provision of health services. We argue that the role of women in planning is central to the provision of effective, efficient and sensitive health-care to conflict-affected populations.  相似文献   
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The performance characteristics of commercially available sulfur dioxide monitors were determined. Con-ductimetric, colorimetric, and coulometric analyzers were investigated. During this phase of the study, characteristics that were more closely related to field operation were studied. These included comparability of data among the instruments over a period of time, weekly calibration drift, maintenance requirements (including operating cost), unattended operation performance, and the effect of rotameter changes on calibration. The methodology and apparatus used to determine each operational parameter are described. The results of this study should be useful in the selection of instruments for monitoring sulfur dioxide.  相似文献   
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To effectively reduce the environmental compliance costs associated with meeting specific requirements under the Aerospace Manufacturing and Rework Facility's National Emission Standard for Hazardous Air Pollutants rule, the U.S. Environmental Protection Agency's (EPA) Data Quality Objective (DQO) process has been proposed as a suitable framework for developing a scientifically defensible surface compliance monitoring program. By estimating the variability associated with the air cap pressure of high- volume, low-pressure (HVLP) surface-coating spray equipment, the number of monitoring samples necessary for an affected facility to claim compliance with a desired statistical confidence level was established. Using data taken from the pilot test facility, the DQO process indicated that the mean of at least 21 HVLP air cap pressure samples taken over the compliance period must be < or = 10 pounds per square inch (psig) gauge for the facility to claim regulatory compliance with 99.99% statistical confidence. Fewer compliance samples could be taken, but that decision would lead to a commensurate reduction in the compliance confidence level. Implementation of the DQO-based compliance sampling plan eliminates the need for an affected facility to sample all regulated HVLP surface-coating processes while still maintaining a high level of compliance assurance.  相似文献   
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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   
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Internet-based research is increasingly important for conservation science and has wide-ranging applications and contexts, including culturomics, illegal wildlife trade, and citizen science. However, online research methods pose a range of ethical and legal challenges. Online data may be protected by copyright, database rights, or contract law. Privacy rights may also restrict the use and access of data, as well as ethical requirements from institutions. Online data have real-world meaning, and the ethical treatment of individuals and communities must not be marginalized when conducting internet-based research. As ethics frameworks originally developed for biomedical applications are inadequate for these methods, we propose that research activities involving the analysis of preexisting online data be treated analogous to offline social science methods, in particular, nondeceptive covert observation. By treating internet users and their data with respect and due consideration, conservationists can uphold the public trust needed to effectively address real-world issues.  相似文献   
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