Conditioned place preference for mating is preserved in rats with pelvic nerve transection.

Female rats exhibit a conditioned place preference (CPP) for a context paired with mating. The present experiment tested the hypothesis that the activation of the pelvic nerve mediates the reinforcing effects of mating for female rats. Rats underwent bilateral pelvic nerve or sham transection and then received paced mating, nonpaced mating, or the control treatment during a CPP procedure. Pelvic nerve transection did not affect the CPP for paced or nonpaced mating. In tests of paced mating behavior, contact-return latencies following intromissions were significantly shorter in rats with pelvic nerve transection than they were in rats with sham transections. These results show that the pathway conveying the reinforcing effects of mating stimulation does not depend on the integrity of the pelvic nerve, but that activation of the pelvic nerve contributes to the display of paced mating behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

1. Use of a novel laboratory stream system to study the ecological impact of PCB exposure in a periphytic biolayer

This research on PCB impact in stream sediments seeks to integrate ecological perspectives into the traditional physicochemical approach to hydrophobic organic chemical (HOC) study. This paper presents the design and use of a novel laboratory stream system with a natural sediment substrate to study the response of a periphytic biolayer to low level PCB exposure over a 2-month time period. The results demonstrate that the laboratory stream system is a powerful tool to evaluate the biological impact and fate of PCBs. The results of biological monitoring demonstrated that the structure of the periphytic community changed with exposure to PCBs. The periphytic community shifted from one dominated solely by a diverse array of diatom taxa to one co-dominated by fewer types of cyanobacteria (blue–green algae) and a single diatom taxon. This suggests that the structural changes in the community are a good early bioindicator of contamination, whereas periphyton biomass (chlorophyll a and biovolume), cell number or the presence/absence of particular species are not sensitive measures for assessing the ecological impact of pollutants.     

Recovery from udder cleft dermatitis in dairy cows

Udder cleft dermatitis (UCD) is a common skin problem in dairy cows, localized at the fore udder attachment or between the udder halves. The main objectives of this study were to investigate spontaneous recovery from UCD in a longitudinal study and to investigate the treatment effect on UCD of a topical spray containing chelated copper and zinc in an additional treatment trial. Spontaneous recovery was investigated during a 1-yr longitudinal study in which 7 Swedish dairy herds were visited 9 times each, at 6-wk intervals. During the visits, all cows milked in the milking parlor were examined for mild and severe UCD, udder conformation traits, hygiene, and hock lesions. Additional cow and herd data were obtained from the Swedish official milk recording scheme. Recovery was defined as 2 consecutive observations of no UCD after a UCD case (1 or more consecutive observations of UCD). The recovery rate was calculated and factors associated with recovery were analyzed using discrete-time survival analysis. A treatment study was conducted in 4 of the herds after completion of the longitudinal study. Cows with UCD were allocated to treatment or a control group, and cows in the treatment group were treated once every day for 14 to 28 d. At follow-up visits on d 14, 28, and 56, all cows were scored for UCD. To investigate the effect of treatment, an ordered logistic regression model was used, with UCD score on d 56 (no, mild, or severe) as the outcome. Other potential explanatory variables were also included in the model. A total of 38% (126 of 329) of the cows in the longitudinal study made a spontaneous recovery from UCD. A long duration of UCD, severe lesions and higher parity reduced the chance of recovery. Among the recovered cows, 47% (59 of 126 cows) had a recurrent case of UCD after the recovery. In the treatment study, there was no difference in UCD score on d 56 between the treatment and control groups. Factors that affected the UCD score on d 56 were the duration of UCD before the treatment study started, UCD score on d 1 and udder conformation. Our findings emphasize the importance of further studies to identify effective treatment regimens as well as further studies to unravel the pathophysiology of UCD to improve the recommendations on how to prevent these lesions.     

Platinum oxidation and sulphur deactivation in NO x storage catalysts

A review covering some of the key catalytic transformations of the major monoterpene feedstocks. Monoterpenes are key ingredients in the flavor and fragrance industry, with α- and β-pinene (obtained from turpentine) being some of the most important. The review focuses on the hydrocarbons; pinene, limonene, carene, and the interconversion of the monooxygenates; geraniol/nerol, citronellol, citral, and citronellal. The major areas covered are catalytic hydrogenation/hydrogenolysis, dehydrogenation, rearrangement/isomerization/aromatization, reactions with carbon monoxide, epoxidation, and the addition of alcohols and acids.     

无线传感器网络能量自调Q路由算法

无线传感器是一种非常微小、精密的,内嵌微处理器的设备,其特点在于当传感器在区域内布点后,这些节点不能再充电;所以在无线传感器网络设计中,能量的开销及网络负载平衡是首先应考虑的因素.提出了一种能量自调式Q路由算法(Q routing with energy and position awareness).使用开放的模拟器OMNET ,比较了QREA协议与传统的路由协议一完全位置路由(geographical routing)的性能.通过实验得出了一个近优化的路由模型.     

Motion Control of Rigid Robot Manipulators via First and Second Order Sliding Modes

A motion control strategy for rigid robot manipulators based on sliding mode control techniques and the compensated inverse dynamics method is presented in this paper. The motivation for using sliding mode mainly relies on its appreciable features, such as simplicity and robustness versus matched uncertainties and disturbances. Furthermore the proposed approach avoids the estimation of the time-varying inertia matrix. As a preliminary step a first order sliding mode control law is presented. Then a second order strategy is discussed. In both cases the problem of chattering, typical of sliding mode control, is suitably circumvented. Simulations results demonstrates the good tracking properties of the proposed control strategy.     

The imagination market

Information markets are typically used as prediction tools, aggregating opinions about the likelihood of future events, or as preference indicators, identifying participants’ product preferences. However, the basic information market concept is more widely applicable. In our experiment, we utilized information markets within the domains of idea generation and group decisioning. Participants were allowed to propose ideas regarding potential technology research areas; these ideas were represented as securities on a virtual financial market. Participants were able to trade shares of technology ideas over the course of 3 weeks, resulting in the market identifying the “best” idea as the highest priced security. Our findings suggest that information markets for idea generation result in more ideas and more participants than traditional idea generation techniques; however, using markets to rank ideas may be no better than other methods of idea ranking. Additional benefits include providing immediate feedback, allowing visibility of all ideas to all contributors, and being a fun mechanism for consensus building.     

Trading reliability targets within a supply chain using Shapley's value

The development of complex systems involves a multi-tier supply chain, with each organisation allocated a reliability target for their sub-system or component part apportioned from system requirements. Agreements about targets are made early in the system lifecycle when considerable uncertainty exists about the design detail and potential failure modes. Hence resources required to achieve reliability are unpredictable. Some types of contracts provide incentives for organisations to negotiate targets so that system reliability requirements are met, but at minimum cost to the supply chain. This paper proposes a mechanism for deriving a fair price for trading reliability targets between suppliers using information gained about potential failure modes through development and the costs of activities required to generate such information. The approach is based upon Shapley's value and is illustrated through examples for a particular reliability growth model, and associated empirical cost model, developed for problems motivated by the aerospace industry. The paper aims to demonstrate the feasibility of the method and discuss how it could be extended to other reliability allocation models.     

Estimating rate of occurrence of rare events with empirical bayes: A railway application

Classical approaches to estimating the rate of occurrence of events perform poorly when data are few. Maximum likelihood estimators result in overly optimistic point estimates of zero for situations where there have been no events. Alternative empirical-based approaches have been proposed based on median estimators or non-informative prior distributions. While these alternatives offer an improvement over point estimates of zero, they can be overly conservative. Empirical Bayes procedures offer an unbiased approach through pooling data across different hazards to support stronger statistical inference.This paper considers the application of Empirical Bayes to high consequence low-frequency events, where estimates are required for risk mitigation decision support such as as low as reasonably possible. A summary of empirical Bayes methods is given and the choices of estimation procedures to obtain interval estimates are discussed. The approaches illustrated within the case study are based on the estimation of the rate of occurrence of train derailments within the UK. The usefulness of empirical Bayes within this context is discussed.