Auction equilibrium strategies for task allocation in uncertain environments

In this paper we address a model of self interested information agents competing to perform tasks. The agents are situated in an uncertain environment while different tasks dynamically arrive from a central manager. The agents differ in their capabilities to perform a task under different world states. Previous models concerning cooperative agents aiming for a joint goal are not applicable in such environments, since self interested agents have a motivation to deviate from the joint allocation strategy, in order to increase their own benefits. Given the allocation protocol set by the central manager, a stable solution, is a set of strategies, derived from an equilibrium where no agent can benefit from changing its strategy given the other agents ’ strategies. Specifically we focus on a protocol in which, upon arrival of a new task, the central manager starts a reverse auction among the agents, and the agent who bids the lowest cost wins. We introduce the model, formulate its equations and suggest equilibrium strategies for the agents. By identifying specific characteristics of the equilibria, we manage to suggest an efficient algorithm for enhancing the agents ’ calculation of the equilibrium strategies. A comparison with the central allocation mechanism, and the effect of environmental settings on the perceived equilibrium are given using several sample environments

Nascent RNA antagonizes the interaction of a set of regulatory proteins with chromatin.

A number of regulatory factors are recruited to chromatin by specialized RNAs. Whether RNA has a more general role in regulating the interaction of proteins with chromatin has not been determined. We used proteomics methods to measure the global impact of nascent RNA on chromatin in embryonic stem cells. Surprisingly, we found that nascent RNA primarily antagonized the interaction of chromatin modifiers and transcriptional regulators with chromatin. Transcriptional inhibition and RNA degradation induced recruitment of a set of transcriptional regulators, chromatin modifiers, nucleosome remodelers, and regulators of higher-order structure. RNA directly bound to factors, including BAF, NuRD, EHMT1, and INO80 and inhibited their interaction with nucleosomes. The transcriptional elongation factor P-TEFb directly bound pre-mRNA, and its recruitment to chromatin upon Pol II inhibition was regulated by the 7SK ribonucleoprotein complex. We postulate that by antagonizing the interaction of regulatory proteins with chromatin, nascent RNA links transcriptional output with chromatin composition

Community college transfer students’ probabilities of baccalaureate receipt as a function of their prevalence in four‐year colleges and departments

The present paper determines whether community college transfer students have higher baccalaureate rates when they enroll in four‐year colleges and departments that have larger shares of transfer students. Transfers attending non‐technical campuses with larger shares of transfers have higher eight‐year baccalaureate rates, but within‐campus increases in share transfers do not increase transfer graduation rates. Transfers in departments with large shares of transfer students have significantly lower graduation rates, but natives in such departments do not. Within‐department increases in transfer student presence are positively correlated with transfer eight‐year graduation rates and negatively correlated with native eight‐year graduation rates, indicating an opportunity for efficiency gains if influxes of transfers are separated from natives.peer effects, transfer education, community colleges, human capital,

Estudos histoplásticos da interação Colletotrichum gloeosporioides: cafeeiro Histopathological studies of the interaction Colletotrichum gloeosporioides: coffee tree

Nos estudos envolvendo a interação Colletotrichum gloeosporioides-cafeeiro (Coffea arabica L.), poucas são as informações a respeito do modo de penetração e colonização deste patógeno. Estudou-se por meio da microscopia eletrônica de varredura (MEV), os eventos de pré-penetração e penetração de C. gloeosporioides em hipocótilos de cafeeiros e a colonização natural de ramos e frutos provenientes de plantas com mancha manteigosa. Realizaram-se três ensaios. No primeiro, fez-se a observação dos eventos de pré-penetração de C. gloeosporioides inoculados em hipocótilos de plântulas da cv. Acaiá Cerrado com e sem ferimentos; no segundo, observou-se a colonização de ramos enfermos em que havia murcha drástica e necrose local e, no terceiro, a colonização de frutos enfermos. A germinação dos conídios nos hipocótilos feridos ocorreu 6 horas após a inoculação, com a formação de um ou dois tubos germinativos terminais e a adesão dos conídios nas depressões dos hipocótilos. Apressórios globosos a subglobosos e de contorno regular surgiram 12 horas após a inoculação. Até 72 horas, não foi possível observar a formação de acérvulos sobre os tecidos submetidos à inoculação. Nos ramos observava-se colonização nos vasos floema e parênquima cortical. Nos frutos em diferentes estádios de maturação foi observada a colonização do tecido próximo à epiderme e colapso dos estômatos na área lesionada.<br>In studies involving the interaction Colletotrichum gloeosporioides - coffee trees (Coffea arabica L.) there is little information regarding the pre-penetration, penetration and colonization pathways of this pathogen. The objectives of this work were: 1. to study through scanning electron microscopy (SEM) the pre-penetration and penetration events of C. gloeosporioides in hypocotyls of coffee plantlets; 2. to observe the colonization of Colletotrichum spp. in branches and fruits of coffee trees with blister spot symptoms. The study took place in three trials. In the first trial, it was observed and reported the pre-penetration events of C. gloeosporioides inoculated on hypocotyls of coffee cv. Acaiá Cerrado with and without wounds. The second trial was performed to investigate the colonization of diseased coffee branches that presented drastic wilt and local necrosis was observed. Finally the third trial investigated the colonization of this pathogen in diseased coffee fruits. When C. gloeosporioides was inoculated, germination could be observed in wounded hypocotyls 6 hours after inoculation. Better adhesion of conidia was evident at surface depressions of hypocotyls and germination started by emission of one or two terminal germ tubes. Round or sub-round shaped apressoria appeared 12 hours after inoculation. Up to 72 hours, acervula formation was not observed on inoculated tissues. The wilted branches presented colonization in the phloem and cortical tissues. In fruits at different stages of maturation, it was observed colonization in tissues near the epidermis and collapse of the stomata in the affected area

Some problems with property ascription

We discuss the practice of property ascription in anthropology. While recognizing that it is an inevitable and often useful way to convey the knowledge that anthropologists have acquired through ethnographic fieldwork, we identify three of the most common ways in which ascription can be misleading. First, when a property is ascribed to a collective entity, but it is unevenly distributed among social sub-groupings; second, when an ascribed mental property is alleged to cause an individual's behaviour, but the property proves to be empirically unsupported; third, when a belief is ascribed to an individual, while another belief that effectively contradicts the first one is also entertained by that same individual. We review anthropological and psychological solutions to these problems