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1.
Flavonoid wing pigments increase attractiveness of female common blue (Polyommatus icarus) butterflies to mate-searching males 总被引:1,自引:0,他引:1
Common blue butterflies (Polyommatus icarus) sequester flavonoids from their larval host plants and allocate these UV-absorbing pigments to the wings. In field experiments
using dummies constructed from female butterflies, mate-searching males inspected flavonoid-rich dummies more intensively
than those with little or no flavonoids. Flavonoid content as signalled by UV-wing pattern may indicate ontogenetically determined
female quality or enhance detectability to males.
Received: 21 March 2000 / Accepted in revised form: 17 May 2000 相似文献
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2,2′-Dichlorodivinylarsine chloride (Lewisite II) react by room temperature quickly with alcohols in an equilibrium reaction to yield 2,2′-Dichlorodivinylarsine ether. The reactions are not quantitative. The methyl-, ethyl-and propylether are not stable. 相似文献
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Many reports and studies have noted that a significant portion of problem-oriented coastal science does not actually link to decisions. Here, three competitively funded project case studies are studied to determine what funders can and should do to better link science with decisions. The qualitative analysis used for this study indicates that the studied program was seen as being unusually attentive to the issue of linking science to decisions, as opposed to simply generating new knowledge. Nevertheless, much of the data indicate that funders can and should do more. Three ideas figured most prominently in the qualitative data: (1) funders should do more to ensure that the problem itself is defined more thoroughly with people who are envisioned as potential users of the science; (2) funders need to allocate more resources and attention to communicating effectively (with users) throughout the project; and (3) funders need to demand more engagement of users throughout the project. These findings have important implications for how funders review and support science, especially when competitive processes are used. Most importantly, funders should adjust what kind of science they ask for. Secondly, funders need to change who is involved in the review process. Currently, review processes focus on knowledge generation, which means that the reviewers themselves have expertise in that area. Instead, review panels should be balanced between those who focus on knowledge generation and those who focus on linking knowledge to decisions; this is a separate but critical discipline currently left out of the review process. 相似文献
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Factors influencing farmers’ decisions on nitrogen fertilizer application in the Liangzihu Lake basin,Central China 总被引:3,自引:0,他引:3
Jin Zhang Günther Manske Pi Qi Zhou Bernhard Tischbein Mathias Becker Zhao Hua Li 《Environment, Development and Sustainability》2017,19(3):791-805
Overuse of nitrogen (N) fertilizers in agriculture activities has caused severe water pollution in China. The lack of data at producer level hampers decision makers in the development and implementation of efficient policies to curb excessive N-fertilizer use. In a survey of 300 farm households in the Liangzihu Lake basin, we identified factors associated with farmers’ decisions on N-fertilizer use and application rate. Household survey and multiple linear regression models indicate that the average application rate in the study region is 229 kg N ha?1, which exceeds the recommended rate for maximum profit for cereal crops (maize, wheat, and rice) in China of 150–180 kg N ha?1. High N-application rates are associated with low farmland productivity (coefficient = ?15.66, p = 0.02), a high share of off-farm income (coefficient = 27.14, p = 0.003), and a low education level of the household head (coefficient = ?10.83, p = 0.039). Neither physical infrastructure nor access to input markets appears to be related to N-application rates. It may be concluded that excessive use of N in agriculture of Central China is mainly a problem of insufficient awareness and high share of off-farm income. 相似文献
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Arsenic geochemistry and health 总被引:19,自引:0,他引:19
Arsenic occurs naturally in the earth's crust and is widely distributed in the environment. Natural mineralization and activities of microorganisms enhance arsenic mobilization in the environment but human intervention has exacerbated arsenic contamination. Although arsenic is useful for industrial, agricultural, medicinal and other purposes, it exerts a toxic effect in a variety of organisms, including humans. Arsenic exposure may not only affect and disable organs of the body, especially the skin, but may also interfere with the proper functioning of the immune system. This paper, therefore, generally highlights the toxic effects of arsenic as well as its mobilization in the natural environment and possible controls. It also briefly attempts to outline the impact of arsenic on the immune system, whose alteration could lead to viral/bacterial infections. 相似文献
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Consanguineous partners had a boy with campomelic dysplasia who died of increasing respiratory distress soon after birth. The next pregnancy was monitored frequently by ultrasonography and a healthy male infant was born at term. During a further pregnancy, ultrasonography suggested campomelic dysplasia in the 16th week of gestation. This was confirmed in the 18th week. The pregnancy was terminated and the fetus showed the typical radiological, anatomical and histological findings. 相似文献
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