Social status in relation to Sindbis virus infection clearance in greenfinches

The ability to resist infections can differ between individuals of different social rank. This study investigates if the clearance of an avian virus infection (Sindbis virus) was related to the social status of greenfinches (Carduelis chloris) and if infected birds would decline in social status. The results showed that virus clearance patterns were related to social status. Within groups of birds with similar plumage color (a social status signal), body mass and age, a birds social status could be used to predict virus clearance patterns. Dominant birds had higher virus concentrations early in the infection and lower virus titres during later stages of the infection as compared to birds that were subordinates. The infection had no significant effect on previously established social ranks, and ranks that were established during the infection did not appear to be influenced by a birds infection status. In conclusion, this study exemplifies a case where the social rank of an individual was a predictor of the ability to clear a viral infection. The underlying physiological mechanisms of this relationship remain to be further investigated.Communicated by C. Brown     

Nontraditional settlement patterns and typhoon hazard on contemporary Majuro atoll,Republic of the Marshall Islands

Low-lying islands and atolls are particularly prone to storm surges created by tropical depressions and typhoons. This paper presents a case study of traditional and contemporary settlement patterns of Majuro, the capital of the Republic of the Marshall Islands, and discusses its vulnerability to such storm surges. The paper shows that the application of traditional knowledge extends to the realm of urban planning and that, in fact, ignoring this traditional knowledge as expressed in pre-World War II settlement patterns, exposes urban development to increased flood hazards, a risk which may exact a price too high in life and property.     

缝纫工腰椎X线检查改变与下背痛的初步调查

５７名缝纫流水线作业工人和３１名缝纫作业辅工的腰椎Ｘ线检查发现，有腰椎改变者分别为８０．７０％ 和７４．１９％ 。其中以骨质增生最多，其次为脊柱侧弯。骨质增生与年龄，工龄有关。下背痛与骨质增生间未见相关关系     

BENTHIC INVERTEBRATES IN A NORTH-FLOWING STREAM AND A SOUTH-FLOWING STREAM,BROOKS RANGE,ALASKA1

ABSTRACT: Benthic invertebrate faunas were compared to two fifth-order streams, the Atigun River flowing northward and the Dietrich River flowing southward. Sixty-eight taxa were collected, forty-nine from each stream. Aquatic insects comprised 88% of the taxa and 97% of the individuals from the Dietrich River and 73% of the taxa and 97% of the individuals from the Atigun River. Diptera, especially Chironomidae, were most abundant. Plecoptera, Ephemeroptera, Oligochaeta, Acarina, and Collembola were significant. In both streams the headwaters were dominated by the subfamily Diamesinae which was replaced by Orthocladiinae downstream. Diversity seemed to increase with stream order. Cluster analysis showed a high degree of resemblance between the benthic faunas of the rivers. Faunal resemblance decreased with increasing distance between stations, both within and between the streams. Although some taxa may occur in only one stream, the evidence for faunal resemblance is stronger than for faunal differences. Other studies have shown that differences in total radiation associated with valley aspect affect local climate, hydrology, and distribution of terrestrial plants and animals. However, the benthic faunas of Atigun and Dietrich Rivers were remarkably similar. Factors which operate independently of aspect, possibly freezing solid in winter, may control the occurrence of species in these streams.     

LIMNOLOGICAL PROPERTIES OF A ROCKY MOUNTAIN HEADWATER RESERVOIR1

ABSTRACT: Hyalite Reservoir, Montana, was studied to determine properties of this small, montane, headwater, deep-release reservoir relative to reservoirs at lower elevations. While retention times for waters were as brief as 12 d, the mean residency of 40 d from mid-March to mid-December was within the range reported for other reservoirs. No significant through-reservoir gradients for suspended sediments were observed, contrasting to observations for most reservoirs. Thermal stratification, evident during the first part of the summer, was disrupted in August by cool, dense tributary inflows and strong wind-induced mixing. Dissolved oxygen concentrations paralleled temperature patterns in the reservoir; lowest average values for both occurred in waters sampled nearest the outlet. Total phosphorus averaged greater than twice the total nitrogen concentrations; greatest average concentrations for both were found in the near-bottom waters nearest the outlet. Enrichment of nitrogen concentrations in outflow over inflow waters is hypothesized to occur through nitrogen fixation by Aphanizonwnon flos-aquae. Despite the relatively high quality of waters from tributary inflows, an algal bloom, chlorophyll a concentrations, and primary productivity estimates suggested that the reservoir was mesotrophic. Circulation of waters within the reservoir was primarily influenced by wind-induced mixing, thermal gradients, and currents produced by the deep-water outlet.     

公共场所泄漏、中毒事故的个人风险水平的估计

笔者研究目的在于对人群聚集公共场所某种类型事故所导致的个人风险进行定量。首先,在前期研究的基础上,推出人群聚集公共场所个人风险定量计算模型。其次,根据火灾的发生率、死亡率及两类事故之间的发生次数比率,估计出国内毒物泄漏、中毒事故发生率和死亡率。最后,根据个人风险的定义求得公共场所毒物泄漏、中毒事故的个人风险的初始值,并进行了进一步的结论修正。对比国外的个人风险标准,结果表明,从整体上看2001—2005年公共场所毒物泄漏、中毒事故的个人风险是可以接受的。该研究结论可以为制定我国个人风险标准提供理论参考依据。     

核电厂密封段加速寿命试验研究

堆芯中子注量率测量系统是30万千瓦核电厂监测系统的重要组成部分之一。该系统中的密封段要在工作温度不大于100℃、设计压力为17.16 MPa条件下满足长期密封要求。根据Arrhenius定律及《机械密封试验方法》,计算出了保证密封段正常工作5 a不泄漏需在240℃条件下进行加速寿命试验所需的试验时间。同时还制定了密封段加速寿命试验方案并进行了加速寿命试验,对试验测量参数进行了分析。分析结果表明密封段满足正常工作5 a不泄漏的要求。密封段加速寿命试验是密封段型式试验的重要步骤,还可作为其它密封设备加速寿命试验的参考。     

某型手榴弹用延期组合件改进设计研究

通过分析某式手榴弹用延期组合件长期贮存的失效机理,改进了药剂配方,优化了结构设计,并通过了试验验证.试验结果表明,该方法提高了手榴弹用延期组合件的长期贮存的安定性,有效解决了手榴弹用延期组合件长期贮存失效的问题.     

Association patterns among wild chimpanzees (<Emphasis Type="Italic">Pan troglodytes schweinfurthii</Emphasis>) reflect sex differences in cooperation

Theory predicts that frequent dyadic association should promote cooperation through kin selection or social tolerance. Here we test the hypothesis that sex differences in the strength and stability of association preferences among free-ranging chimpanzees conform to sex differences in cooperative behavior. Using long-term data from the Kanyawara chimpanzee (Pan troglodytes schweinfurthii) community (Kibale National Park, Uganda), we calculated indices of intra-sexual dyadic association over a 10-year period. We found that (1) male–male dyads had significantly stronger association indices than female–female dyads, (2) the pattern of association preferences in both sexes changed little over the entire study period, and (3) when comparing periods with different alpha males, changes in association strength were more frequent among males. These results demonstrate that both the strength and stability of association patterns are important components of social relationships. Male chimpanzees, which are characterized by frequent cooperation, had association preferences that were both strong and stable, suggesting that forming long-term bonds is an important dominance strategy. However, the fact that male association patterns were sensitive to upheaval in the male dominance hierarchy suggests that males also take advantage of a changing social climate when choosing association partners. By contrast, the overall strength of female associations was relatively weak. Female association preferences were equally stable as males’; however, this reflected a dyad’s tendency to be found in the same party rather than to associate closely within that party. Therefore, in this community, female association patterns appear to be more a consequence of individual ranging behavior rather than a correlate of cooperation.     

An ergonomics study on wrist posture when using laparoscopic tools in four techniques in minimally invasive surgery

Purpose. With reference to four minimally invasive surgery (MIS) cholecystectomies, the aims were (a) to recognize the factors influencing dominant wrist postures manifested by the surgeon; (b) to detect risk factors involved in maintaining deviated wrist postures; (c) to compare the wrist postures of surgeons while using laparoscopic tools. Methods. Video films were recorded during live surgeries. The films were synchronized with wrist joint angles obtained from wireless electrogoniometers placed on the surgeon's hand. The analysis was conducted for five laparoscopic tools used during all surgical techniques. Results. The most common wrist posture was extension. In the case of one laparoscopic tool, the mean values defining extended wrist posture were distinct in all four surgical techniques. For one type of surgical technique, considered the most beneficial for patients, more extreme postures were noticed regarding all laparoscopic tools. We recognized a new factor, apart from the tool's handle design, that influences extreme and deviated wrist postures. It involves three areas of task specification including the type of action, type of motion patterns and motion dynamism. Conclusions. The outcomes proved that the surgical technique which is best for the patient imposes the greatest strain on the surgeon's wrist.?