Limb regeneration and subsequent asymmetry in a male secondary sexual character influences sexual selection in wolf spiders

Males of the brush-legged wolf spider Schizocosa ocreata (Hentz) have conspicuously decorated forelegs used in courtship and agonistic displays. Approximately one in five juvenile males has a missing or regenerating foreleg, and regeneration of a leg lost during development usually results in the absence of a decorative tuft on that leg. The subsequent asymmetry in this male secondary character significantly decreases success in both courtship of females and male-male agonistic interactions. Experimental removal of tufts from one leg of previously successful symmetric males produces similar results. As a test for concomitant behavioral effects, female spiders were shown video images of a courting male with symmetric tufts and the same video image altered to have asymmetric tufts. Female receptivity to the asymmetric video image was lower. In contrast to fluctuating asymmetry resulting from developmental instability, leg tuft asymmetry in S. ocreata most likely arises from a single event during ontogeny – possibly leg loss from an aggressive or predator encounter  – and may serve as a quality indicator in female mate choice. Received: 27 July 1995/ Accepted after revision: 19 November 1995     

Permanent exposure versus facultative concealment of sexual traits: an experimental study in the house sparrow

In many bird species the cryptic winter plumage is due to the presence of light feather tips that conceal conspicuous colorations. The gradual abrasion of these tips that makes sexual traits visible has been interpreted as a strategy to improve mating success (here referred as the permanent exhibition hypothesis). However, under some circumstances, the maintenance of a full plumage that facultatively enables the bird to exhibit or cover aggression-inducing traits has proved to be advantageous (the coverable badge hypothesis). In a population of house sparrows where black throat patches (here called badges) are used in intrasexual competition, the degree of abrasion of dull feather tips that conceal bright colour early in the breeding season correlated neither with badge size nor with traits indicating morphology and body condition. These results are only in accordance with predictions of the coverable badge hypothesis. In 1992 experimental clipping of badge feather tips, which forced permanent exposure of badges, negatively affected birds with the largest badges in terms of nest acquisition, but an opposite trend was indicated for birds with the smallest badges. In 1993, when more novel birds in the study area were competing for nesting sites than in 1992, only badge size, but not the experimental manipulation, affected nesting success. These results suggest that the loss of the ability to conceal badges was disadvantageous, and more so if most competing individuals had already been resident in the colony in previous years and the larger their badges were. There is a striking contrast between the results reported for this study population, where badges mainly signal fighting ability, and those reported for another house sparrow population, where badges are mainly used in mate choice. In this last population, tip abrasion is advantageous for dominant individuals showing the largest badges. This suggests that the trade-off between conserving versus wearing off the feathers that conceal ornaments could have different optimal resolutions depending on the relative importance of inter and intrasexual selection on indicator traits. Received: 29 September 1995/Accepted after revision: 14 July 1996     

Manipulation of Olfactory Signaling and Mate Choice for Conservation Breeding: a Case Study of Harvest Mice

Abstract:  Mate choice by females can introduce difficulties to captive breeding programs because there may be a conflict between the conservation manager's choice of mate (based on random allocation or maximizing heterogeneity) and the females' own preferences, often resulting in incompatibility and aggression. Similar effects are caused by inappropriate social contexts at the time of pairing. We manipulated the social experience of male and female harvest mice ( Micromys minutus ) to investigate whether we could enhance compatibility between randomly allocated mates by altering female preferences. In one experiment, we used a choice test to identify female preferences between two males and then varied the competitive context of unpreferred males by transferring competitor's scent marks into their cages. The manipulation caused them to increase their investment in a form of olfactory signaling (scent marking), which female rodents use as an indicator of male quality when choosing mates. The manipulation increased their attractiveness relative to the initially preferred male when the choice test was repeated. In a second experiment, we tested the effect of females' familiarity with the odor of males by transfer of male scent marks to female cages. Females preferred familiar males in choice tests and were less aggressive toward them when pairs were introduced than females paired with unfamiliar males. This kind of approach can influence mate choice, and transferring scent marks between cages or collections is an effective and practical behavioral means of improving success in conservation breeding programs.     

Personal desires of patients and social obligations of geneticists: applying preimplantation genetic diagnosis for non-medical sex selection

The arguments against the use of preimplantation genetic diagnosis (PGD) for non-medical sex selection are analysed. It is concluded that the distinction between medical and non-medical reasons is difficult to maintain, that the disproportionality of means and end is not a decisive counterargument and that the fear of damage to the reputation of PGD does not justify the refusal of controversial applications. Moreover, since non-medical sex selection does not belong to basic health care, it should not be equally accessible to all. The position defended in this article is founded on two basic principles: (1) medical reasons have priority on non-medical reasons, and (2) personal reasons do not qualify for public funding. In order to respect both principles, it is proposed that restrictions should be installed to control the number of requests for social sexing and that a tax should be imposed on these elective services. The tax should compensate the society for the investment it made in the training and education of the physician. Copyright © 2002 John Wiley & Sons, Ltd.     

瀑河水库蓄水后水质变化预测

瀑河水库拟作为南水北调中线的一个调蓄水库。在瀑河水库淹没区内布10个采样点，分别采集0－20、20－40、40－60cm深度的土壤，实验室中模拟水库蓄水淹没情景，连续监测“库水”水质，试验表明：蓄水初期土壤中营养物质溶出对库水水质有一定影响，且随着时间的推移，各营养物质溶出的速度及浓度变化不同，蓄水16天后浓度趋于平稳，库水水质达到地表水环境质量Ⅱ类标准，将模拟值作为初始值，利用WQRRS模型进行运行期水质预测，得到结论为：（1）当调水水质为Ⅰ和Ⅱ类标准值的中值、流域汛期径流水质为Ⅱ－Ⅴ类时，预测库水水质为Ⅱ－Ⅲ类；（2）当调水水质为Ⅱ类标准值的下限值、流域汛期径流水质为Ⅱ－Ⅴ类时，预测库水水质大多为Ⅲ类，部分情况下为Ⅳ类，且N、P超标；（3）当调水水质为Ⅰ和Ⅱ类标准值的中值、流域径流水质为Ⅱ类时，在2010、2020和2030水平年水库水质全部为Ⅱ类；当调水水质为Ⅱ类标准值的下限值时库水水质则为Ⅲ类。     

获取日均值的大气监测时段选择

利用数理统计方法，以污染物瞬时监测数据为基础数据，选用控制在一定置信度下最大允许误差的统计公式确定出样本容量，并采用模糊集合运算—优化组合选择法，确定出获取日均值的最佳监测时段．     

浅谈环境监测分析实验室在流动分析技术上的选择

从环境监测实验室的角度对比了流动分析技术中目前比较常用的2种技术(即FIA和SFA)的优缺点,并指出目前在环境监测实验室中最适用的技术。     

半结构决策方法在松花江蓄洪区选址问题中的研究

研究松花江蓄洪区选址问题的决策方法.松花江蓄滞洪区选址问题涉及诸多定性指标和定量指标,属于半结构决策问题.本文综合层次分析法和模糊优选法,提出求解这类问题的一种半结构决策方法.基本方法是:将评价指标分为定性指标和定量指标;对于定性应用层次分析法,求其评价矩阵;对于定量指标应用相对隶属度方法,求其评价矩阵;二者合成得到全体指标的评价矩阵;最后利用模糊优选法求得最优决策.应用该方法于松花江流域蓄滞洪区的方案选择中.     

化工园区定量风险评价中危险源初选方法的研究

在进行化工园区定量风险评价中,危险源的梳理和筛选是首要步骤。分析了欧盟ARAMIS方法、荷兰PURPLE BOOK方法和新西兰的HFSP方法在危险源初选中的适用性,指出对于区域危险源初选用HFSP方法可以全面考虑区域中的各类危险源,快速准确地对危险源进行排序,并提出了HFSP方法用于区域危险源初选的调整方法,给出了危险设施单元的定义和进行QRA的选择判据。     

基于DEMATEL方法的海运行为形成因子影响关系分析

为揭示并量化海运人因可靠性分析(HRA)中行为形成因子(PSF)间复杂的影响关系,采用DEMATEL方法对航海人员值班任务中9个PSF的依赖关系进行建模和分析,并验证该方法的有效性。结果表明:船上组织的完善程度、驾驶台班组成员的合作质量、可用时间等PSF在系统中的作用大;船上组织的完善程度、人机界面(MMI)与运行支持的完善性、值班区间以及培训和准备的充分性4个PSF为原因因素,驾驶台班组成员的合作质量、同时出现的目标任务数量、可用时间、船上工作及船舶航行条件和操作规程/计划的可用性5个PSF为结果因素。安全管理人员应针对作用大或原因因素中的PSF制定安全管理措施,改善情景环境,提高人因可靠性。