Allocating the weights in the linear opinion pool

A standard approach to the combination of probabilistic opinions involves taking a weighted linear average of the individuals distributions. This paper reviews some of the possible interpretations that have been proposed for these weights in the literature on expert use. Several paradigms for selecting weights are also considered. Special attention is devoted to the Bayesian mechanism used for updating expert weights in the face of new information. An asymptotic result is proved which highlights the importance of choosing the initial weights carefully.     

从服务中心到战略推动者:香港中文大学信息化建设的未来展望

香港中文大学历经半个世纪风雨,如今已发展成为世界知名研究型大学.与此同时,计算机和网络技术的日新月异,极大地改变着人们的生活、学习、工作和社交模式,也给大学提出了源源不断的新挑战.如今,IT已不再是实验室里高高在上的尖端科技,而是维持社会正常运作的基础设施和服务,并且拥有着巨大的潜力给生活带来更多的智慧.作为高等教育的IT部门,如何应对这业务格局的转变,如何了解和满足用户日益提升的服务需求,如何发挥IT技术的价值以推动大学战略发展,都是我们应当考虑的问题.本文将介绍香港中文大学的信息化管理与发展现状,讨论当前遇到的问题并分析应对方法,探索为实现大学信息化战略推动者之愿景应选择的未来道路.     

Epitypification： should we epitypify？

Epitypification can solve many taxonomic problems and stabilize the understanding of species, genera, families or orders. The aim of this paper is to illustrate how to epitypify. A few examples where taxa have been epitypified are considered and the benefits and disadvantages of epitypification are discussed. We also outline some examples of taxa which need to be epitypifled with reasons.     

Recent Advances in the Development of Polymer-supported Phosphines

1 Introduction Recent years have seen a growing use of polymer-supported reagents by organic chemists in traditional solution-phase synthesis.Of the many reagents supported by polymers available, variations of triphenylphosphine are among the most broadly used. This is because triphenylphosphine is not only a reagent in a wide range of organic reactions~([1]), but it also serves as a ligand in many organometallic reagents~([2]).Most importantly, polymer-supported triphenylphosphine affords the…     

STRATEGIC EXERCISE OF REAL OPTIONS：INVESTMENT DECISIONS IN TECHNOLOGICAL SYSTEMS

Viewing investment projects in new technologies as real options, this paper studies the effects ofendogenous competition and asymmetric information on the strategic exercise of real options. We firstdevelop a multi-period, game-theoretic model and show how competition leads to early exercise andaggressive investment behaviors and how competition erodes option values. We then relax the typicalfull-information assumption found in the literature and allow information asymmetry to exist acrossfirms. Our model shows, in contrast to the literature that payoff is independent of the ordering ofexercise, that the sequential exercise of real options may generate both informational and payoffexternalities. We also find some surpising but interesting results such as having more information isnot necessarily better.     

Intragenic tandem repeats generate functional variability

Tandemly repeated DNA sequences are highly dynamic components of genomes. Most repeats are in intergenic regions, but some are in coding sequences or pseudogenes. In humans, expansion of intragenic triplet repeats is associated with various diseases, including Huntington chorea and fragile X syndrome. The persistence of intragenic repeats in genomes suggests that there is a compensating benefit. Here we show that in the genome of Saccharomyces cerevisiae, most genes containing intragenic repeats encode cell-wall proteins. The repeats trigger frequent recombination events in the gene or between the gene and a pseudogene, causing expansion and contraction in the gene size. This size variation creates quantitative alterations in phenotypes (e.g., adhesion, flocculation or biofilm formation). We propose that variation in intragenic repeat number provides the functional diversity of cell surface antigens that, in fungi and other pathogens, allows rapid adaptation to the environment and elusion of the host immune system.     

Negative epistasis between the malaria-protective effects of alpha+-thalassemia and the sickle cell trait

The hemoglobinopathies, disorders of hemoglobin structure and production, protect against death from malaria. In sub-Saharan Africa, two such conditions occur at particularly high frequencies: presence of the structural variant hemoglobin S and alpha(+)-thalassemia, a condition characterized by reduced production of the normal alpha-globin component of hemoglobin. Individually, each is protective against severe Plasmodium falciparum malaria, but little is known about their malaria-protective effects when inherited in combination. We investigated this question by studying a population on the coast of Kenya and found that the protection afforded by each condition inherited alone was lost when the two conditions were inherited together, to such a degree that the incidence of both uncomplicated and severe P. falciparum malaria was close to baseline in children heterozygous with respect to the mutation underlying the hemoglobin S variant and homozygous with respect to the mutation underlying alpha(+)-thalassemia. Negative epistasis could explain the failure of alpha(+)-thalassemia to reach fixation in any population in sub-Saharan Africa.     

Electronic tagging and population structure of Atlantic bluefin tuna

Electronic tags that archive or transmit stored data to satellites have advanced the mapping of habitats used by highly migratory fish in pelagic ecosystems. Here we report on the electronic tagging of 772 Atlantic bluefin tuna in the western Atlantic Ocean in an effort to identify population structure. Reporting electronic tags provided accurate location data that show the extensive migrations of individual fish (n = 330). Geoposition data delineate two populations, one using spawning grounds in the Gulf of Mexico and another from the Mediterranean Sea. Transatlantic movements of western-tagged bluefin tuna reveal site fidelity to known spawning areas in the Mediterranean Sea. Bluefin tuna that occupy western spawning grounds move to central and eastern Atlantic foraging grounds. Our results are consistent with two populations of bluefin tuna with distinct spawning areas that overlap on North Atlantic foraging grounds. Electronic tagging locations, when combined with US pelagic longline observer and logbook catch data, identify hot spots for spawning bluefin tuna in the northern slope waters of the Gulf of Mexico. Restrictions on the time and area where longlining occurs would reduce incidental catch mortalities on western spawning grounds.