Seasonal life cycle and autogeny in the mosquitoAedes togoi in northern Kyushu, Japan, with experimental analysis of the effects of temperature, photoperiod and food on life-history traits

We studied seasonal changes in the larval population structure, adult size, and autogeny (egg production without a bloodmeal) of the mosquitoAedes togoi on the seacoast of northern Kyushu, Japan. The effects of temperature, photoperiod and food conditions on larval development, adult size and autogeny were studied in the laboratory.Aedes togoi overwintered in both the egg and larval stages and was multivoltine. Adult size was greater in spring and autumn and smaller in summer. Autogeny occurred in spring and autumn but not in summer. Autogenous females were larger than anautogenous females, and larger autogenous females produced more eggs. Laboratory experiments showed that autogeny was promoted under low temperature and short-day conditions which corresponded with spring/autumn conditions in the field. Experimental food limitation in the larval stage greatly reduced adult size and autogenous egg production. In the field, large inter-pool variations in adult size and autogeny rate probably resulted from variations in nutrient and crowding conditions. Seasonal autogeny ofAedes togoi was discussed in terms of life-history strategy under fluctuating environmental conditions where relative advantages of autogenous and anautogenous reproduction alternate seasonally.     

Factors and consequences of a non-functional alary polymorphism inPyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

Functional alary polymorphisms have been studied rather extensively in several insect species. This review article deals with factors controlling wing polymorphism in a flightless species,Pyrrhocoris apterus (L.), and discusses its adaptive significance and mechanisms for their persistence under natural conditions. The macropterous morph is determined by a recessive allele whose penetrance depends on photoperiod and temperature. Natural populations of this species contain a small fraction of flightless macropters. The disadvantages of being a macropter (increase of development time, decrease of fecundity) are minimal, while the benefit may consist in the tendency to prereproductive arrest of ovarian development in teneral females. It prevents establishing a second generation which would mostly die during the next winter. The mechanism of alary morph regulation may be an ancestral trait linkingP. apterus with other polymorphic Heteroptera, while its decreased penetrance may be a derivative character. Variation in fitness due to alary morphs is small compared to the one associated with differences in body size. The latter is environmentally determined, and not linked to the genetic basis of wing polymorphism. In the “mosaic” of phenotypes of various size the significance of the genetic macroptery may be close to neutral.     

Longevity, flight ability and reproductive performance of the diamondback moth,Plutella xylostella (L.) (Lepidoptera: Yponomeutidae), related to adult body size

Plutella xylostella in the temperate zone shows a clear seasonal change in adult body size. In the laboratory, large and small moths were produced during immature stages at 15°C and 25°C, respectively. These moths were then used to evaluate longevity, age-specific flight ability, flight ability of mated and unmated females, and the influence of flight experience on the subsequent reproductive success. The large moths lived longer and displayed a greater flight ability over 3 weeks. Irrespective of body size, unmated females flew for a longer time than mated females, and flight experience affected their subsequent reproductive success. Females of both sizes mated and laid eggs soon after emergence, without any obvious pre-reproductive period. More flight experience did not delay oviposition, but did reduce egg production. It is likely that large moths with a longer adult life span and greater flight ability are better fitted for long-distance flight and more fecund than small ones. These experimental results may explain why long-distance migration ofP. xylostella is mostly seen during cool seasons, when relatively large moths with long forewing appear in the field.     

可视化技术在机器马步行机构尺度综合系统中的应用

科学计算可视化是近年来发展起来的一门新兴技术。本文就机器马步机构尺度综合系统中可视化技术的应用作一介绍，以探讨和扩大可视化技术的应用范围。     

A Sociodemographic Risk Index

In this paper, we conceptualize and develop an index of sociodemographic risk that we hypothesize will be an improvement over the standard poverty measure as a measure of risk for children’s development. The poverty line is widely used in government statistics and in research but is also widely acknowledged to have multiple shortcomings. Using recent data from the National Survey of America’s Families, we develop and examine a Sociodemographic Risk Index for two potential purposes: (a) to serve as a summary indicator of children’s environments that affect their well-being, and (b) to serve as a variable that can be used to identify at-risk subgroups of children whose well-being should be examined separately in indicator reports. Based on substantial research on children’s development, we chose five variables for the index: family income, family structure, parent education, family size, and home ownership. An additive sociodemographic risk index using these variables is strongly associated with multiple measures of child well-being in both bivariate and multivariate analyses. Hence, it serves as a good marker of risk for children and therefore as an indicator that could be monitored over time, across groups, and across places, as well as a variable that could be used to identify subgroups of at-risk children whose well-being should be monitored. However, analyses do not indicate that it performs better at identifying at-risk children than the current poverty measure. Therefore, we recommend the Sociodemographic Risk Index primarily as an additional summary indicator to be monitored, rather than as a replacement for the poverty measure.     

家庭规模缩小对家庭经济保障能力的影响:苏南实例

本文通过实验设计方法 ,并利用苏南农村居民的数据资料 ,分析实证了在有收入积累的前提下 ,家庭规模缩小不仅不会弱化家庭保障能力 ,而且会强化家庭保障能力。不同规模家庭保障能力差别 ,随时间推移和在家庭生命周期的不同阶段具有波动性。家庭保障能力会因家庭规模的大小、消费和积累模式的差异和在家庭生命周期中的不同阶段而不同 ,并可能发生相互转换。     

论中国城市规模分布的区域差异

本文分析了建国以后中国三大地区的城市增长状况 ,三大地区的城市规模分布特征及其成因 ,探讨了中国中、西部地区城市规模结构的缺陷可能给对外开放和西部大开发带来的负面影响 ,同时指出了“控制大城市规模”的城市发展方针与对外开放政策、社会主义市场经济体制的建立以及西部大开发战略等的矛盾。本文认为 :大城市是地区经济发展的“增长极” ,中、西部地区缺少具有较大影响范围的大城市和特大城市 ,使得这些地区在市场经济条件下和改革开放过程中的创新机会和领先条件大为减少 ,而且会影响到西部大开发战略的顺利实施     

Framing,probability distortions,and insurance decisions

A series of studies examines whether certain biases in probability assessments and perceptions of loss, previously found in experimental studies, affect consumers' decisions about insurance. Framing manipulations lead the consumers studied here to make hypothetical insurance-purchase choices that violate basic laws of probability and value. Subjects exhibit distortions in their perception of risk and framing effects in evaluating premiums and benefits. Illustrations from insurance markets suggest that the same effects occur when consumers make actual insurance purchases.Presented at the Conference onMaking Decisions about Liability and Insurance, The Wharton School, University of Pennsylvania, Philadelphia, PA, 6–7 December, 1991. This research is supported by National Science Foundation Grant SES88-09299. The authors thank Jon Baron, Colin Camerer, Neil Doherty, Paul Kleindorfer, Amos Tversky, and two anonymous referees for many helpful comments. We particularly acknowledge the efforts of Matthew Robinson and Penny Pollister for their help with data analysis.     

Why Doesn't Technology Flow From Rich to Poor Countries?

What is the role of a country's financial system in determining technology adoption? To examine this, a dynamic contract model is embedded into a general equilibrium setting with competitive intermediation. The terms of finance are dictated by an intermediary's ability to monitor and control a firm's cash flow, in conjunction with the structure of the technology that the firm adopts. It is not always profitable to finance promising technologies. A quantitative illustration is presented where financial frictions induce entrepreneurs in India and Mexico to adopt less‐promising ventures than in the United States, despite lower input prices.     

Robust group testing for multiple traits with misclassification

Determining group size is a crucial stage before conducting experiments using group testing methods. Considering misclassification, we propose D-criterion and A-criterion to determine a robust group size for screening multiple infections simultaneously. Extensive simulation shows the advantage of the proposed method when the goal is estimation.