达尔文对我的影响

查尔斯·达尔文生于1809年2月12日。200年后,他在我的祖国英国成了民族英雄。全世界各地都在以各种形式纪念他的200年诞辰,比如,电视、广播、图书、博物馆展览、研讨会,以及各种各样的活动。今年也正值达尔文的著作《物种起源》——这本备受争议的书一一出版150年。     

Measurement of non-randomness in spatial distributions

Summary The measurement of departure from randomness in spatial distributions has widespread application in ecological work. Several “indices of non-randomness” are compared with regard to their dependence on sample number, sample size and density. Criteria for the best choice of index for specific situations are discussed. A new coefficientC _x is proposed for use with positively contagious distributions and tests of significance are given. WhenC _x and another index (S ²/m−1) are used for positive and negative contagion respectively, values ranging from −1 through 0 (random) to +1 are obtained, regardless of sample number, sample size or density.     

Cultural Endorsement of Broad Leadership Prototypes and Wealth as Predictors of Corruption

Corruption is a social ill that involves public officials’ misuse of entrusted power, which is a function of sociocultural factors. Rarely, however, do researchers view corruption as a leadership-related problem. In the current research, we conceptualize corruption as a leadership-related problem, and propose three broad leadership prototypes based on social value orientation theory and research. We seek to examine (1) how cultural endorsement of self-serving, prosocial, and individualistic leadership prototypes is related to corruption at the societal level and (2) how wealth moderates the relationship between cultural endorsement of self-serving leadership and corruption. Using archival data of 53 societies, we found that cultural endorsement of self-serving leadership was positively related to corruption, strengthened by wealth. Cultural endorsement of prosocial leadership and individualistic leadership, however, was not significantly related to corruption, and wealth did not moderate either of the relationships. The implications of these findings for theory and future research are discussed.     

INSTRUCTING OPERATIONS DESIGN: AN EXPERIENTIAL APPROACH

Teaching an operations design course has major pedagogical challenges. (1) The design topics—output, process, facility, and work design—are necessarily taught sequentially, yet the decisions are integrative. (2) Instruction must be generic to service or product producers. (3) Discussing output design is difficult since students typically have had no exposure to the “product language” of engineering graphics. (4) No text is available which examines in sufficient depth all the operations design decisions. (5) Cases necessarily depict historical situations—process technologies and economic data—while operations managers must plan future directions for their productive systems. (6) While the commercial world contains fresh information and data, students are inexperienced in obtaining knowledge from the real world. (7) While the course presents an operations management perspective, students must recognize the information, data, and cooperation necessary from the other functional areas to successfully complete the operations design. To help overcome these seven pedagogical challenges, the students in the undergraduate and graduate operation design courses complete a comprehensive feasibility study for a new product or service and the entire productive system.     

Trends in bird species richness,abundance and biomass along a tropical urbanization gradient

Impacts of urbanization on biodiversity are commonly studied using urbanization gradients which provide a space-for-time substitution in estimating consequences of urban expansion. Rates of urbanization and human population growth are high in tropical countries of the developing world, which also hold most of the world’s biodiversity hot-spots, yet few studies have considered biodiversity trends along urban gradients in these regions. Bird communities across a gradient of nine sites in Uganda, from the city centre of Kampala to outlying rural locations, were studied over a six year period. These sites were ordered along an urbanization gradient using Principle Components Analysis based on habitat variables estimated at each site. Bird species richness showed a decrease from rural to urban sites, a trend especially evident in forest birds. There was no clear pattern in total abundance, total biomass or biomass per individual along the gradient. However, this latter result was heavily influenced by a colony of Marabou Storks at one site. When this species was omitted, there was evidence of a positive trend with urbanization, showing that as species richness decreased, the bird community was increasingly dominated by larger species with increasing urbanization, which were mainly scavengers able to exploit human refuse. These results provide further support for the negative impacts of urbanization on species richness, but also demonstrate trends in abundance and biomass are variable across different regions. In particular, the increasing dominance of larger species in urban areas may be relevant to certain geographic and/or socioeconomic contexts.     

Residential Remittances and Food Security in the Upper West Region of Ghana

In recent years, out migration from the Upper West Region to the southern belt of Ghana for farming has become commonplace. The natural question that has arisen is: what is the potential impact of remittances from this migration pattern on food security in the region? Using multivariate ordered logistic regression this study assesses the linkage between remittances and household food security (derived using the HFIAS) among urban and rural households (n=1,438) in the region. The findings show that urban remittance‐receiving households and rural remittance and non‐remittance receiving households were more likely (OR=2.44, p<0.05; OR=2.46, p<0.001; and OR=1.49, p<0.1, respectively) to report being more severely food‐insecure than urban non‐remittance receiving households. The findings demonstrate that household strategies such as migration and remittances on their own are not sufficient to ameliorate the precarious food insecurity situation of the region. The study calls for development of alternative livelihoods in the region.     

A cross-border perspective on migration: beyond the assimilation/transnationalism debate

The transnational perspective emerged in the early 1990s as an alternative to assimilation theory, gaining instant and wide influence. But curiously, the intellectual confrontation between these two perspectives was averted, as scholars concluded that persistent homeland engagement was fully compatible with hostland integration. This paper seeks to pick up that challenge. I demonstrate how a cross-border perspective, encompassing places of origin and destination and the flows of people, ideas, and resources between them, highlights the ways in which population movements across state borders create tensions on both receiving and sending sides. In the process, I will show how looking across borders paradoxically highlights the centrality of the territorial boundary, as it simultaneously underscores the importance of dissimilation – the social and political separation of immigrants from the people they have left behind – yet also the ways in which non-citizen status and foreign origins simultaneously hamper immigrants’ ability to gain acceptance in receiving states while furnishing sending states with opportunities to reconnect with nationals abroad.     

The Use of Simulation to Reduce the Domain of “Black Swans” with Application to Hurricane Impacts to Power Systems

Recently, the concept of black swans has gained increased attention in the fields of risk assessment and risk management. Different types of black swans have been suggested, distinguishing between unknown unknowns (nothing in the past can convincingly point to its occurrence), unknown knowns (known to some, but not to relevant analysts), or known knowns where the probability of occurrence is judged as negligible. Traditional risk assessments have been questioned, as their standard probabilistic methods may not be capable of predicting or even identifying these rare and extreme events, thus creating a source of possible black swans. In this article, we show how a simulation model can be used to identify previously unknown potentially extreme events that if not identified and treated could occur as black swans. We show that by manipulating a verified and validated model used to predict the impacts of hazards on a system of interest, we can identify hazard conditions not previously experienced that could lead to impacts much larger than any previous level of impact. This makes these potential black swan events known and allows risk managers to more fully consider them. We demonstrate this method using a model developed to evaluate the effect of hurricanes on energy systems in the United States; we identify hurricanes with potentially extreme impacts, storms well beyond what the historic record suggests is possible in terms of impacts.