8 resultados para Sexual selection in animals

em Aston University Research Archive


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This paper suggests a data envelopment analysis (DEA) model for selecting the most efficient alternative in advanced manufacturing technology in the presence of both cardinal and ordinal data. The paper explains the problem of using an iterative method for finding the most efficient alternative and proposes a new DEA model without the need of solving a series of LPs. A numerical example illustrates the model, and an application in technology selection with multi-inputs/multi-outputs shows the usefulness of the proposed approach. © 2012 Springer-Verlag London Limited.

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The pharmacological effects of a number of centrally acting drugs have been compared in euthyroid mice and mice made hyperthyroid by pretreatment with sodium-1-thyroxine. The potencies of two barbiturates, pentobarbitone and thiopentone - as indicated by the duration of their hypnotic actions and their acute toxicities - are increased in hyperthyroid mice. An acutely active uncoupler of phosphorylative oxidation is 2, 4-dinitrophenol, an agent which proved to be a potent hypnotic when administered intracerebrally. An attempt has been made to relate the mechanism of action of the barbiturates to the uncoupling effects of thyroxine and 2, 4-dinitrophenol. The pharmacological effects of chlorpromazine, reserpine and amphetamine-like drugs have also been studied in hyperthyroid mice. After pretreatment with thyroxine, mice show a reduced tendency to become hypothermic after chlorpromazine or reserpine; in fact, under suitable laboratory conditions these agents produce a hyperthermic effect. Yet their known depressant effects upon locomotor activity were not substantially altered. Thus it appeared that depression of locomotor activity and hypothermia are not necessarily correlated, an observation at variance with previously held opinion. These results have been discussed in the light of our knowledge of the role of the thyroid gland in thermoregulation. The actions of tremorine and its metabolite, oxotremorine, have also been examined. Hyperthyroid animals are less susceptible to both the hypothermia and tremor produced by these agents. An attempt is made to explain these observations, in view of the known mechanism of action of oxotremorine and the tremorgenic actions that thyroxine may have. A number of experimental methods have been used to study the anti-nociceptive (analgesic) effects of drugs in euthyroid and hyperthyroid mice. The sites and mechanisms of action of these drugs and the known actions of thyroxine have been discussed.

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This paper presents the first academic case study of a UK cyberstalking incident that involved an individual known to have harassed at least four victims. The case study describes how the harasser selected victims, his use of technology to gather confidential information about them and his use of multiple personalities as part of the process of harassment. The discussion section of the paper raises a broad range of issues, including whether the case represents a genuine cyberstalking incident, how technology was used to assist the harasser's activities and how the harasser attempted to avoid detection

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OBJECTIVE: Breast cancer diagnosis and treatments can have a profound impact upon women's well-being, body image, and sexual functioning, but less is known about the relational context of their coping and the impact upon their intimate partners. Our study focuses upon couples' experiences of breast cancer surgery, and its impact on body image and sexual intimacy. METHOD: Utilizing a dyadic design, we conducted 8 semistructured individual interviews, with 4 long-term heterosexual couples, after the women had undergone mastectomy with reconstruction. Interviews explored both partners' experiences of diagnosis, decision-making, and experiences of body image and sexual intimacy. Interpretative phenomenological analysis (IPA) was adopted; this is a qualitative research approach characterized by in-depth analysis of the personal meaning of experiences. RESULTS: Findings illustrate the positive acceptance that partners may express toward their wives' postsurgical bodies. They illuminate ways in which gendered coping styles and normative sexual scripts may shape couples' negotiations of intimacy around "altered embodiment." Reciprocal communication styles were important for couples' coping. The management of expectations regarding breast reconstruction may also be helpful. CONCLUSIONS: The insights from the dyadic, multiple perspective design suggest that psychologists must situate the meaning of supportive relationships and other protective factors in the context of complex life events and histories, in order to understand and support people's developing responses to distress. (PsycINFO Database Record

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Relay selection has been considered as an effective method to improve the performance of cooperative communication. However, the Channel State Information (CSI) used in relay selection can be outdated, yielding severe performance degradation of cooperative communication systems. In this paper, we investigate the relay selection under outdated CSI in a Decode-and-Forward (DF) cooperative system to improve its outage performance. We formulize an optimization problem, where the set of relays that forwards data is optimized to minimize the probability of outage conditioned on the outdated CSI of all the decodable relays’ links. We then propose a novel multiple-relay selection strategy based on the solution of the optimization problem. Simulation results show that the proposed relay selection strategy achieves large improvement of outage performance compared with the existing relay selection strategies combating outdated CSI given in the literature.

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We compare spot patterns generated by Turing mechanisms with those generated by replication cascades, in a model one-dimensional reaction-diffusion system. We determine the stability region of spot solutions in parameter space as a function of a natural control parameter (feed-rate) where degenerate patterns with different numbers of spots coexist for a fixed feed-rate. While it is possible to generate identical patterns via both mechanisms, we show that replication cascades lead to a wider choice of pattern profiles that can be selected through a tuning of the feed-rate, exploiting hysteresis and directionality effects of the different pattern pathways.

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Selection in privatization is a decision-making process of choosing state-owned enterprises (SOEs), prioritizing and sequencing privatizing events, and determining the extent of private ownership in partial privatization. We investigate this process in an important but rarely studied case of China. Based on the SOE population over 1998-2008, we track 49,456 wholly SOEs and identify 9,359 privatization cases over time. Our econometric analysis concludes: (i) The privatization selection is a complex decision-making process in which local governments balance between various economic, financial and political objectives. (ii) In the recent Chinese privatization, firm performance relates to the selection, staging and sequencing in privatization in an inverted-U fashion. The worse and the best performing SOEs are more likely to remain state-owned, maintain higher state holding when privatized, and are less likely to be privatized later in time. These patterns suggest the privatization reform slowdown and the underlying changes in the privatization policy.