Seasonality and vertical structure of light-attracted insect communities in a dipterocarp forest in Sarawak

Nocturnal flying insects were collected monthly for 13 months using ultra violet light-traps set at various vertical levels in a weakly-seasonal, tropical lowland dipterocarp forest in Sarawak, Malaysia. Abundance, faunal composition, size distribution and guild structure of these samples were analyzed with respect to temperal and vertical distributions. The nocturnal flying insect community in the canopy level was highly dominated by fig wasps (84%) in individual number, and by scarabaeid beetles (28%) in weight. A principal component analysis on monthly catches detected non-random, seasonal trends of insect abundance. The first two principal trends were an alternation of wetter (September to January) and less wet seasons (February to August) and an alternation between the least wet (January to March) and the other seasons. Many insect groups were less abundant in the least wet season than the other seasons, whilst inverse patterns were found in Scarabaeidae and Tenebrionidae. Significantly positive and negative correlations between monthly catch and rainfall were detected only in ovule-feeders and in phloem-feeders, respectively. Delayed, significant negative correlations between monthly catch and 1–3 month preceding rainfall were more frequently detected in phytophages, phloem-feeders, seed-feeders, wood-borers and scavengers. The peak in abundance along vertical levels were found at the canopy level (35 m) for phloem-, ovule-, seed-, root-, fungal-feeders and nectar collectors, at an upper subcanopy level (25 m) for scavengers and aquatic predators, and at a middle subcanopy level (17 m) for ants. Catches at the emergent level (45 m) did not exceed those at the canopy level.     

Robust estimation for linear regression with asymmetric errors

The authors propose a new class of robust estimators for the parameters of a regression model in which the distribution of the error terms belongs to a class of exponential families including the log‐gamma distribution. These estimates, which are a natural extension of the MM‐estimates for ordinary regression, may combine simultaneously high asymptotic efficiency and a high breakdown point. The authors prove the consistency and derive the asymptotic normal distribution of these estimates. A Monte Carlo study allows them to assess the efficiency and robustness of these estimates for finite samples.     

On the identification of ARMA echelon-form models

An identification procedure for multivariate autoregressive moving average (ARMA) echelon-form models is proposed. It is based on the study of the linear dependence between rows of the Hankel matrix of serial correlations. To that end, we define a statistical test for checking the linear dependence between vectors of serial correlations. It is shown that the test statistic t?_n considered is distributed asymptotically as a finite linear combination of independent chi-square random variables with one degree of freedom under the null hypothesis, whereas under the alternative hypothesis, t?_N/N converges in probability to a positive constant. These results allow us, in particular, to compute the asymptotic probability of making a specification error with the proposed procedure. Links to other methods based on the application of canonical analysis are discussed. A simulation experiment was done in order to study the performance of the procedure. It is seen that the graphical representation of t?_N, as a function of N, can be very useful in identifying the dynamic structure of ARMA models. Furthermore, for the model considered, the proposed identification procedure performs very well for series of 100 observations or more and reasonably well with short series of 50 observations.     

Dynamic Simulation as an Approach to Understanding Hurricane Risk Response: Insights from the Stormview Lab

This article investigates the use of dynamic laboratory simulations as a tool for studying decisions to prepare for hurricane threats. A prototype web‐based simulation named Stormview is described that allows individuals to experience the approach of a hurricane in a computer‐based environment. In Stormview participants can gather storm information through various media, hear the opinions of neighbors, and indicate intentions to take protective action. We illustrate how the ability to exert experimental control over the information viewed by participants can be used to provide insights into decision making that would be difficult to gain from field studies, such as how preparedness decisions are affected by the nature of news coverage of prior storms, how a storm's movement is depicted in graphics, and the content of word‐of‐mouth communications. Data from an initial application involving a sample of Florida residents reveal a number of unexpected findings about hurricane risk response. Participants who viewed forecast graphics, which contained track lines depicting the most likely path of the storm, for example, had higher levels of preparation than those who saw graphics that showed only uncertainty cones—even among those living far from the predicted center path. Similarly, the participants who were most likely to express worry about an approaching storm and fastest to undertake preparatory action were those who, ironically, had never experienced one. Finally, external validity is evidenced by a close rank‐order correspondence between patterns of information use revealed in the lab and that found in previous cross‐sectional field studies.     

The Gender Wage Gap in the Turkish Labor Market

Abstract. This paper examines the sources of the gender wage gap in the Turkish labor market by using matched employer–employee data and the standard wage regression estimations as well as the Oaxaca decomposition method. The extensive number of variables in the data set enables a thorough quantitative analysis of the role of various individual‐ as well as firm‐related factors leading to wage differentials between men and women, namely human capital endowments including job tenure, occupational and industrial segregation, private/public sector location, coverage of the workplace under collective labor bargaining, and firm size. It also examines the extent of gender‐based industry and occupational segregation within the confines of data set and computes the Duncan & Duncan segregation index. We find that a large portion of the gender wage gap is attributable to women's considerably lower levels of work experience and job tenure. Other important variables that lead to pay differentials are women's lower concentration in jobs covered by collective labor bargaining and a substantial degree of occupational and industrial segregation. The differential rates of return to many of the wage determinant variables are also found to be significant in the formation of the gender wage gap.     

让你的谈话发挥效力

让我们想象这样一幅场景：一位人类学家来到你的办公室，他用了一整天时间跟在你身边，寸步不离地观察你的一言一行。当你一天工作结束之后，他告诉你，在这一整天当中，他只看到了一件事情——人们在不停地进行沟通。这位人类学家告诉你，在这一天的时间里，他参加了一些正式的会议，看到人们在进行面对面的交流，进行随机的讨论，或者是通过电子邮件进行沟通。“没错，确实如此，”你说道，“可那叉怎样呢？”人类学家告诉你，你在这一天当中所说的话大多数都是重复的。“这很好，”你告诉自己，     

Backward Induction Foundations of the Shapley Value

We present a noncooperative game model of coalitional bargaining, closely based on that of Gul (1989) but solvable by backward induction. In this game, Gul's condition of “value additivity” does not suffice to ensure the existence of a subgame perfect Nash equilibrium that supports the Shapley value, but a related condition—“no positive value‐externalities”—does. Multiple equilibria can arise only in the event of ties, and with a mild restriction on tie‐break rules these equilibria all support the Shapley value.     

几种电路分析方法适用范围的讨论

通过实例讨论了支路电流法、网孔分析法、节点电压法、叠加原理和戴维南定理的适用性 ,最后对电路分析时不同电路如何选用合适方法给出了一个参考性选择     

Global value chains for medical gloves during the COVID-19 pandemic: Confronting forced labour through public procurement and crisis

This paper evaluates ways in which labour issues in global value chains for medical gloves have been affected by, and addressed through, the COVID-19 pandemic. It focuses on production in Malaysia and supply to the United Kingdom's National Health Service and draws on a large-scale survey with workers and interviews with UK government officials, suppliers and buyers. Adopting a Global Value Chain (GVC) framework, the paper shows how forced labour endemic in the sector was exacerbated during the pandemic in the context of increased demand for gloves. Attempts at remediation are shown to operate through both a reconfigured value chain in which power shifted dramatically to the manufacturers and a context where public procurement became higher in profile than ever before. It is argued that the purchasing power of governments must be leveraged in ways that more meaningfully address labour issues, and that this must be part of value chain resilience.