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281.
The function of hatching asynchrony in the blue-footed booby 总被引:3,自引:0,他引:3
The blue-footed booby (Sula nebouxii) commonly hatches two eggs 4 days apart; then the senior (first-hatched) chick aggressively dominates the other and sometimes kills it. Two hypotheses explaining the function of the hatching interval were tested by creating broods with synchronous hatching: the facultative brood reduction hypothesis of Lack (1954) and the sibling rivalry reduction hypothesis of Hahn (1981). The results contradicted most predictions of both hypotheses: synchronous broods formed an aggressive hierarchy similarly to asynchronous broods (controls), and subordinate chicks grew poorly (Fig. 1) and died frequently, similarly to junior chicks in control broods. However, compared with synchronous broods, asynchronous broods showed less aggression (Fig. 2), diminished food allocation to subordinate chicks (Fig. 3) and less total food consumption (30% fewer feeds at age 0–10 days). These behavioral comparisons took into account the different ages of chicks in different treatments. The results suggest that natural asynchrony makes brood reduction more efficient and decreases the costs of sibling aggression to parents, in terms of their future survival or fecundity, as proposed by Mock and Ploger (1987). Further, in exaggeratedly asynchronous broods (8-day hatch interval) junior chicks suffered more aggression (Fig. 4) and grew more slowly than junior chicks in control broods. This result supports the hypothesis of optimal hatch asynchrony of Mock and Ploger (1987). 相似文献
282.
WASP—5系统及其述评 总被引:13,自引:1,他引:13
WASP5(The water quality analysis simulation program-5,水质分析模拟程序5),是EPA推荐使用的水质模型软件。该文介绍了WASP5的组成、功能、原理、应用步骤、适用范围、输入输出,并对其优缺点进行了评论,最后还介绍了WASP5在浦西河网水质模拟中的应用。 相似文献
283.
环境污染与住房价格的计量经济分析模式 总被引:1,自引:0,他引:1
对人的生活环境如何评价进行定量化的探讨,即城市住房价格如何引入计量经济模式,给出一个定量回归分析方法,得出比较科学可靠和准确的结果. 相似文献
284.
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286.
物元分析在水质污染综合评价中的应用 总被引:1,自引:0,他引:1
本文首次提出一种用物元分析进行水质污染综合评价的新方法.该方法将水质级别、评价项目及其特征值作为物元,根据水质分级标准建立关联函数,通过计算综合关联度判断水质级别.用实例与其它方法进行了对比,结果完全一致.该方法计算简便,评价合理,实用性强,具有推广价值. 相似文献
287.
On a small island such as Malta where many developers and policy makers place a large emphasis on social use and develoment
values, which encourages recreational/industrial development, it is often hard to promote the monetary value of coastal conservation
due to strong competition with the large tourism industry. An assessment of the ecological (conservation) and economic (use/development)
values of four popular Maltese bathing areas (Mellieha, St. George’s, Ramla and Ghajn Tuffieha Bay) was carried out by evaluating
their ability to provide a number of functions. This is dependent on the environments’ inherent characteristics within the
context of locally applicable time and space functions. Function Analysis is an innovative technique able to provide a means
for assessing changes in environmental quality of an area and evaluating the sustainability of applied management regimes.
This paper is a first example of an application of the Functional Analysis approach in Malta. Local application of this technique
indicates a need for additional refinement in application to coastal areas. Analysis showed that St. George’s, had the lowest
conservation value, Ramla and Ghajn Tuffieha bay had the highest conservation values, Mellieha Bay had high conservation value
and use/development potential. In this context, conservation value is understood to reflect values of biodiversity, information/knowledge
and environmental quality. 相似文献
288.
289.
重大决策的环境影响评价实证探讨 总被引:2,自引:0,他引:2
该文在阐述亟待建立重大决策环评制度的基础上,提出了重大决策环评的特点,程序,方法,并以江苏省和第三次发展机遇-结构调整为实例,进行实证研究。 相似文献
290.
The Yellow River in winter as source water is characterized as high alkalinity, low temperature and low particle concentrations,
which have brought many difficulties to water treatment plants. This study fully examines the optimized coagulation process
of the Yellow River by conventional and pre-polymerized metal coagulants, pH adjustment and polyelectrolytes as the primary
coagulants or coagulant aids. For all the metal coagulants, polyaluminum chlorides are superior to traditional metal coagulants
due to their stable polymeric species and low consumption of alkalinity. The removal of natural organic matter by monomeric
metal coagulants can be improved through pH adjustment, which is in accordance with the higher concentration of polymeric
species formed at corresponding pH value. With the addition of polyelectrolytes as coagulant aids, the coagulation performance
is significantly improved. The effective removal of dissolved organic matter is consistent with high charge density, while
molecular weight is relatively important for removing particles, which is consistent with polyelectrolytes as primary coagulants.
These results suggest that the coagulation mechanisms in the removal of dissolved organic matter and particles are different,
which may be exploited for optimized coagulation for the typical source water in practice. 相似文献