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1.
ABSTRACT: This paper first discusses the results of sensitivity analyses conducted on various parameters of the San Francisco Stormwater Model ta version of WREM) and the Penn State Runoff Model in terms of their impact on outflow hydrographs. The parameters considered within a idealized catchment include: basin shape, imperivous fraction, overland roughness and slope: deterntion depth; infiltration capacity; and hyetograph timing. Second, the results for the hypothetical catchment are extended to the lazzard laboratory surfaces (asphalt, grass, roofing material) as a mean of illustrating the need for changes in model structure, as opposed to continued parameter adjustment Finally the effect of altering the scale of hydraulic representation in the surface runoff and sewer transport calculations are demonstrated for two gaged watersheds in Hamburg, West Germany.  相似文献   
2.
基于SPA模型的煤矿瓦斯危险源风险评价   总被引:1,自引:0,他引:1  
根据危险源理论和三类危险源的观点,采用集对分析(SPA)方法,进行了安全一事故集对的同异反分析,指出应采取措施控制不确定项,尤其要控制其中的第二类、第三类危险源才能使系统趋于安全状态;同时建立了煤矿瓦斯危险源风险评价模型,通过联系度的计算得出煤矿瓦斯的安全等级.研究表明,将集对分析方法应用于某煤矿瓦斯危险源风险评价,计算简单,结果较为精确、可靠,为不确定系统的评价提供了一条新思路.  相似文献   
3.
Forecasting the temporal trend of a focal species, its range expansion or retraction, provides crucial information regarding population viability. To this end, we require the accumulation of temporal records which is evidently time consuming. Progress in spatial data capturing has enabled rapid and accurate assessment of species distribution across large scales. Therefore, it would be appealing to infer the temporal trends of populations from the spatial structure of their distributions. Based on a combination of models from the fields of range dynamics, occupancy scaling and spatial autocorrelation, here I present a model for forecasting the population trend solely from its spatial distribution. Numerical tests using cellular automata confirm a positive correlation, as inferred from the model, between the temporal change in species range sizes and the exponent of the power-law scaling pattern of occupancy. The model is thus recommended for rapid estimation of species range dynamics from a single snapshot of its current distribution. Further applications in biodiversity conservation could provide a swift risk assessment, especially, for endangered and invasive species.  相似文献   
4.
Individual recognition is generally assumed to be a prerequisite for establishing and maintaining a complex social system. Indeed, there is good evidence that highly social species have complex systems of vocal communication with individual recognition by acoustic cues. In this study, we provide experimental evidence that vocal class and individual recognition is present in a non-passerine bird, the spectacled parrotlet (Forpus conspicillatus). Spectacled parrotlets live in a complex system of social relationships. Soon after fledging, the young establish close sibling relationships which are important for successful socialization, pairing and reproduction. In a series of playback experiments we tested if spectacled parrotlets use contact calls for vocal recognition. The results showed that spectacled parrotlets discriminate between the contact calls of different social categories. Adult birds preferred to respond to the contact calls of their mates. Subadult individuals recognized the contact calls of their siblings. During the period of pair bond formation, the affiliative contacts to the siblings decrease, but the parrotlets continue to respond to the calls of their siblings. This is the first evidence that vocal sibling recognition might outlast the period of strong sibling interaction and extends into the period of pair bond formation. In cases of mate loss or divorce, the acoustic contact to their siblings might facilitate the re-establishment of close sibling relationships. Received: 29 October 1997 / Accepted after revision: 5 April 1998  相似文献   
5.
The results of censuses of 335 bird species and estimation of environmental factors in 1163 habitats located in undeveloped areas of the Western Siberian Plain were analyzed. The data for analysis were obtained from the databank of the Laboratory of Zoological Monitoring of the Institute of Animal Ecology and Systematics (Siberian Division, Russian Academy of Sciences). The material was collected in the first half of summer (between May 16 and July 15) in 1936–1938 and 1959–1999 (mostly beginning from 1967). A learning sample (863 variants) was used to approximate the abundance of each species with respect to each factor (including calculation by the principal-component method), and the approximation was integrated with respect to all these factors. The approximation coefficients were used to make a prognosis of species abundance based on the values of environmental factors in the control sample (300 variants). For the 50 most prevalent species, accounting for more than 80% of total bird abundance, the values of explained variances of approximation and prognosis averaged 53.5 (r = 0.73) and 47% (r = 0.68), respectively.  相似文献   
6.
Biparental incubation is frequent among shorebirds and is expected when the survival prospects of offspring increase relative to uniparental incubation. To understand why this occurs, it is important to identify the factors that constrain uniparental incubation. It is assumed that birds choose nesting sites that provide an appropriate microclimate for incubation. Many shorebirds nest in sites with no or little cover, where ambient temperatures at ground level might be >50°C during very hot days. Shorebirds nest in exposed sites because predation risk on incubating adults is higher in covered sites. In hot environments, incubating shorebirds might experience heat stress in exposed sites, and this may compromise nesting success if adults are unable to attend their nests continuously, limiting the possibilities of uniparental incubation and thus the expression of a sexual conflict over incubation. The operative temperatures of Kentish plovers (Charadrius alexandrinus) were recorded in exposed and covered sites, and the thermal behaviour and incubating tactics of pair members were studied in a hot environment. During the hottest part of the day, there was a difference of 10–15°C in the operative temperatures of plovers between covered and exposed sites. Plovers in covered sites did not exhibit any thermoregulatory behaviour indicative of thermal stress, probably because the thermal range encountered by them in such places during most of the daytime was close to the thermo-neutral zone. The frequency with which plovers in exposed sites exhibited thermoregulatory behaviour was related to ambient temperature. Under very hot conditions, incubating birds were probably unable to maintain homeostasis for long periods and pair members resorted to shortening incubation bouts. Female Kentish plovers mainly incubate in the daytime and males during the night. However, the probability of diurnal incubation by males increased with ambient temperature in exposed nests, but not in covered ones. In fact, the frequency of participation in diurnal incubation by males was greater in exposed than in covered sites, suggesting that the participation of males in diurnal incubation may be related to the inability of females to stay at the nest during long periods when the ambient temperature is high. Even after resorting to shortened incubation bouts, the plovers may be unable to attend their nests continuously during heat waves, and the nests may be deserted. The propensity of plovers to desert their nests was affected by proximity to water, with nests located close to water being deserted less frequently. It seems likely that susceptibility to thermal stress changed in relation to proximity to water because in sites close to water it was possible to belly-soak, which would allow a more continuous nest attendance. Therefore, despite the adoption of behavioural solutions to face heavy heat loads, nesting success was vulnerable to these solutions because heat stress during extended periods may constrain parental nest attendance, and this may limit the opportunities for sexual conflicts over incubation.Communicated by J. Graves  相似文献   
7.
五元联系数在湖泊水质综合评价中的应用   总被引:1,自引:0,他引:1  
集对分析是一种新的处理模糊和不确定问题的系统理论方法,运用同异反表达式可解决各种模糊不确定问题,而五元联系数又是集对分析理论的拓展. 针对当前众多湖泊富营养化评价方法过程复杂繁琐问题,提出利用基于五元联系数的系统态势对湖泊富营养化程度进行等级评价,其评价结果与其他评价方法基本一致;并且用集对分析法对湖泊富营养化程度进行等级评价,评价结果更符合实际情况,对监测数据的利用率高,对营养化程度的划分更细致,能够得到属于同一级别的湖泊富营养化程度的排序. 五元联系数克服了以往集对分析评价级别只有3个等级的缺点,扩大了评价等级范围,因此可在更多领域得到广泛应用.   相似文献   
8.
地下水环境质量评价的一种新方法--集对分析法   总被引:19,自引:0,他引:19  
提出了一种新的地下水环境质量评价模型———集对分析法。该方法是一种处理不确定性问题的理论,其模型数学表达简单,物理意义明确,所含意义深远。研究结果表明:集对分析法简便易行,评价结果准确,在环境质量综合评价中具有广泛的实用价值。  相似文献   
9.
10.
Night-time OH levels have been determined for UK urban surface environments using two methods, the decay and steady state approximation methods. Measurement data from the UK National Environmental Technology Centre archive for four urban sites (Bristol, Harwell, London Eltham and Edinburgh) over the time period of 1996 to 2000 have been used in this study. Three reactive alkenes, namely isoprene, 1,3-butadiene and trans-2-pentene were chosen for the calculation of OH levels by the decay method. Hourly measurements of NO, NO2, O3, CO and 20 VOCs were used to determine night-time OH level using the steady state approximation method. Our results showed that the night-time OH levels were in the range of 1 105–1 106 molecules/cm3 at these four urban sites in the UK. The application of a t-test of these analyses indicated that except Bristol, there was no significant di erence between the OH levels found from the decay and steady state approximation methods. Night-time levels of the OH radical appeared to peak in summer and spring time tracking the night-time O3 levels which also passed through a maximum at this time.  相似文献   
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