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Porcine-specific polymerase chain reaction (PCR) and a pig–rodent somatic cell hybrid panel were used to map two members of the MyoD gene family. MYOD1 was assigned to pig chromosome 2 and MYF5 to chromosome 5.  相似文献   

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Genetic manipulation that reduces the competence of a vector population to transmit pathogens would provide a useful tool to complement current control strategies, which are based primarily on the reduction/exclusion of vector populations and the prophylactic/therapeutic treatment of the vertebrate host population. Genetic drive is an important component of vector population replacement strategies, facilitating the replacement of natural populations with a genetically modified population. Genetic drive is reviewed here, emphasizing strategies that would employ infections of intracellular Wolbachia bacteria as a vehicle for population replacement. Also discussed are strategies for the retarding, arresting or reversing of Wolbachia-based population replacement. These strategies are based upon altering the conditions required for transgene invasion and are a prudent safeguard, should unexpected detrimental effects become associated with transgene spread.  相似文献   

5.
Functional-anatomic correlates of individual differences in memory   总被引:3,自引:0,他引:3  
Kirchhoff BA  Buckner RL 《Neuron》2006,51(2):263-274
Memory abilities differ greatly across individuals. To explore a source of these differences, we characterized the varied strategies people adopt during unconstrained encoding. Participants intentionally encoded object pairs during functional MRI. Principal components analysis applied to a strategy questionnaire revealed that participants variably used four main strategies to aid learning. Individuals' use of verbal elaboration and visual inspection strategies independently correlated with their memory performance. Verbal elaboration correlated with activity in a network of regions that included prefrontal regions associated with controlled verbal processing, while visual inspection correlated with activity in a network of regions that included an extrastriate region associated with object processing. Activity in regions associated with use of these strategies was also correlated with memory performance. This study reveals functional-anatomic correlates of verbal and perceptual strategies that are variably used by individuals during encoding. These strategies engage distinct brain regions and may separately influence memory performance.  相似文献   

6.
Depressed mood in severely obese, bariatric surgery-seeking candidates is influenced by obesity stigma, yet the strategies for coping with this stigma are less well understood. This study hypothesized that coping strategies are significantly associated with depressed mood above and beyond demographic factors and frequency of weight-related stigma, with specific coping strategies differing between racial groups. Severely obese, bariatric surgery-seeking adults (N = 234; 91 African Americans) completed the Beck Depression Inventory (BDI) and Stigmatizing Situations Inventory (SSI). Two hierarchical linear regressions were conducted separately for African Americans and whites. For both racial groups, age, sex, BMI, years overweight, annual income, and education level did not account for a significant portion of the variance in BDI scores. The frequency of stigmatizing situations and coping strategies significantly explained 16.4% and 33.2%, respectively, of the variance for whites, and 25.9% and 25%, respectively, for African Americans (P < 0.001). Greater depressed mood in whites was associated with older age, lower education, fewer positive self-statements, and less self-love and more crying; while in African Americans greater depressed mood was associated only with ignoring the situation (P < 0.05). The study found that regardless of race, depressed mood in severely obese, bariatric surgery-seeking clients is related to the frequency of stigmatizing experiences and associated coping strategies. This suggests that efforts to reduce the deleterious effects of weight-related stigma need to focus both on reducing the frequency of stigmatization and on teaching effective coping strategies. These efforts also need to take into account the client's racial background.  相似文献   

7.
Background and objective Empirical data are scarce regarding the adaptive response to stress for patients with somatoform disorders. Our objective was to identify the preferred coping strategies of patients with abridged somatisation, a common condition in primary care. Because of the functional impairment associated with somatisation, we predicted a preference for less effective, emotion-focused coping strategies over more effective, problem-focused adaptations.Design We conducted a cross-sectional, observational study of physician referred primary care patients who presented with persistent, medically unexplained, physical symptoms. Patients were classified into two abridged somatisation groups by symptom frequency and duration, as determined by the Diagnostic Interview Schedule. The groups were compared with each other and with a non-clinical reference group; outcome variables were eight emotion- and problem-focused strategies, as measured by the Ways of Coping Questionnaire.Results Of the 72 eligible individuals, 48 participated in the study. Median age was 48 years and 75% of patients were women; 26 had somatic syndrome and 22 had a subthreshold somatising level. Patients with abridged somatisation disorders preferred emotion-focused coping strategies - typically detachment and impact minimisation, wishful thinking and problem avoidance.Conclusions Patients with abridged somatising disorder responded to stress with predominantly emotion-focused strategies, which may be associated with a lower level of positive adaptive outcome. Our findings suggest that patients with abridged somatising disorders might benefit from emphasis on problem-focused coping strategies, delivered through primary care, to improve quality of life and decrease healthcare utilisation costs.  相似文献   

8.
Ola Olsson  Joel S. Brown 《Oikos》2010,119(2):292-303
Animals possess different abilities to gain and use information about the foraging patches they exploit. When ignorant of the qualities of encountered patches, a smart forager should leave all patches after the same amount of fixed search time. A smarter forager can be Bayesian by using information on cumulative harvest and time spent searching a patch to better inform its patch‐departure decision. The smartest forager has immediate and continuous knowledge about patch quality, and can make a perfect decision about when to leave each patch. Here we let each of these three strategies harvest resources from a slowly regenerating environment. Eventually a steady‐state distribution of prey among patches arises where the environment‐wide resource renewal just balances the environment‐wide harvest of the foragers. The fixed time forager creates a distribution with the highest mean and highest variance of patch qualities, followed by the Bayesian and the prescient in that order. The less informed strategies promote distributions with both more resources and more exploitable information than the more informed strategies. While it is true that a better‐informed strategy will always out‐perform a less well‐informed, its increase in performance may not compensate it for any costs associated with being better informed. We imagine that the fixed time strategy may be least expensive and the prescient strategy most expensive in terms of sensory organs and associated assess and respond capabilities. To consider competition between such strategies with varying costs, we introduced a single individual of each of the strategies into the environments created by populations of the other strategies. There are threshold costs associated with the better‐informed strategy such that it can or cannot outcompete a less‐informed strategy. However, over a relatively narrow range of foraging costs, less‐informed and better‐informed strategies will coexist. Furthermore, for the prescient and the Bayesian strategies, some combinations of foraging costs produce alternate stable states – whichever strategy establishes first remains safe from invasion by the other.  相似文献   

9.
This paper analyzes feeding strategies in a sequential batch reactor (SBR) with the objective of reaching a given (low) substrate level as quickly as possible for a given volume of water. Inside the SBR, several species compete for a single substrate, which leads to a minimal time control problem in which the control variable is the feeding rate. Following Gajardo et al. (2008) SIAM J Control Optim 47(6):2827–2856, we allow the control variable to be a bounded measurable function of time combined with possible impulses associated with instantaneous dilutions. For this problem, the extremal trajectories of the singular arc type are characterized as the strategies used to maintain the substrate at a constant level. Since this optimization problem is difficult to solve, this characterization provides a valuable tool for investigating the optimality of various feeding strategies. Our aim is thus to illustrate the use of this tool by proposing potential optimal feeding strategies, which may then be compared with other more intuitive strategies. This aim was accomplished via several numerical experiments in which two specific strategies are compared.  相似文献   

10.
Unwanted cats surrendered to nonhuman animal shelters are generally categorized as either “owned” or “stray.” This classification is misleading because “stray” cats may include many “semiowned” cats, for which people provide care but who are not perceived as being owned. This differentiation is important because effective strategies designed to reduce cat admissions to, and euthanasia rates in, shelters rely on accurate information about cat populations contributing to shelter intake; cat semiowners will likely respond to different strategies than people with no relationship with the cats they surrender. People surrendering cats to four Australian animal shelters were surveyed to identify factors associated with perception of ownership. Many self-classified nonowners had fed the cats they surrendered, often for a considerable period of time. The factor most strongly associated with ownership perception was an increasing association time with the cat. These findings confirm that enduring relationships between surrenderers and cats, consistent with cat semiownership, are common for cats surrendered to Australian animal shelters. This finding should be taken into account when planning education messages and cat population management strategies aimed at reducing cat admissions.  相似文献   

11.
This study examined the role of religious and nonreligious cognitive-behavioral coping in a sample of 61 chronic pain patients from a midwestern pain clinic. Participants described their chronic pain and indicated their use of religious and nonreligious cognitive-behavioral coping strategies. Results supported a multidimensional conceptualization of religious coping that includes both positive and negative strategies. Positive religious coping strategies were associated significantly with positive affect and religious outcome after statistically controlling for demographic variables. In contrast, measures of negative religious coping strategies were not associated significantly with outcome variables. Several significant associations also were found between nonreligious cognitive-behavioral coping strategies and outcome variables. The results underscore the need for further research concerning the contributions of religious coping in adjustment to chronic pain. Practitioners of applied psychophysiology should assess their chronic pain patients' religious appraisals and religious coping as another important stress management strategy.  相似文献   

12.
Much social psychological research has been dedicated to understanding mating strategies from the standpoint of genetic-fitness payout (e.g., Simpson and Gangestad, 2000). The current work is designed to provide a coherent, quantitative model for predicting different classes of mating strategies in both males and females. Specifically, the framework developed in this paper is an elaboration of Dawkins' (1989) quantitative assessment of different male and female mating strategies. Dawkins suggests that the prevalence of different strategies employed should be predictable in terms of evolutionary stable strategies. In the current work, a quantitative analysis predicting the prevalence of different mating strategies within each sex was conducted. The mathematical functions derived suggest that variability in the costs associated with raising offspring affects the expected prevalence of mating strategies differently for males and females. According to the present model, variability in female strategies should be less affected by changes in parental investment (PI) than variability in male strategies. Important predictions regarding male and female mating strategies across cultures are discussed.  相似文献   

13.
Molecular techniques have revealed striking variation among bird species in the rates of extra-pair paternity (EPP) and intraspecific brood parasitism (IBP). In terms of the proportion of broods affected, rates of EPP and IBP vary across species from 0-95% and 0-50%, respectively. Despite a plethora of hypotheses and several careful comparative analyses, few robust correlates of this interspecific variation have been identified. One explanation for this shortfall is that most comparative studies have tended to focus on contemporary ecological factors and ignored fundamental differences in reproductive biology that evolved millions of years ago. We show that, for both EPP and IBP, over 50% of interspecific variation is due to differences among taxonomic families and orders. Therefore, we test hypotheses that predict interspecific variation in the rate of alternative reproductive strategies should be associated with differences in life history and the form of parental care. Our analyses largely support these predictions, with high rates of reproductive cheating being associated with 'fast' life histories. High EPP rates are associated with high rates of adult mortality and reduced paternal care. High IBP rates are associated with high-fecundity rates. These patterns remain intact whether we use species as independent data points or evolutionary contrasts based on either molecular or morphological phylogenies. These results are interpreted as supporting the idea that alternative reproductive strategies are most common in taxa in which the risks of retaliation are low. We suggest a hierarchical explanation for interspecific variation in the incidence of alternative reproductive strategies. Variation between major avian lineages in the EPP and IBP rates are determined by fundamental differences in life history and parental care that evolved many millions of years ago. Variation between populations or individuals of the same species, however, are more likely to be determined by differences in contemporary ecological and genetic factors.  相似文献   

14.
The Chicxulub bolide impact caused the end-Cretaceous mass extinction of plants, but the associated selectivity and ecological effects are poorly known. Using a unique set of North Dakota leaf fossil assemblages spanning 2.2 Myr across the event, we show among angiosperms a reduction of ecological strategies and selection for fast-growth strategies consistent with a hypothesized recovery from an impact winter. Leaf mass per area (carbon investment) decreased in both mean and variance, while vein density (carbon assimilation rate) increased in mean, consistent with a shift towards “fast” growth strategies. Plant extinction from the bolide impact resulted in a shift in functional trait space that likely had broad consequences for ecosystem functioning.  相似文献   

15.
Toward an ecological synthesis: a case for habitat selection   总被引:15,自引:0,他引:15  
Morris DW 《Oecologia》2003,136(1):1-13
Habitat selection, and its associated density and frequency-dependent evolution, has a profound influence on such vital phenomena as population regulation, species interactions, the assembly of ecological communities, and the origin and maintenance of biodiversity. Different strategies of habitat selection, and their importance in ecology and evolution, can often be revealed simply by plots of density in adjacent habitats. For individual species, the strategies are closely intertwined with mechanisms of population regulation, and with the persistence of populations through time. For interacting species, strategies of habitat selection are not only responsible for species coexistence, but provide one of the most convenient mechanisms for measuring competition, and the various community structures caused by competitive interactions. Other kinds of interactions, such as those between predators and prey, demonstrate that an understanding of the coevolution of habitat-selection strategies among strongly interacting species is essential to properly interpret their spatial and temporal dynamics. At the evolutionary scale, the frequency dependence associated with habitat selection may often allow populations to diverge and diversify into separate species. Habitat selection thereby demonstrates how we can map microevolutionary strategies in behavior onto their population and community consequences, and from there, onto macroevolutionary patterns of speciation and adaptive radiation. We can anticipate that future studies of habitat selection will not only help us complete those maps, but that they will also continue to enrich the panoply of ideas that shape evolutionary ecology.  相似文献   

16.
Abstract

Much social psychological research has been dedicated to understanding mating strategies from the standpoint of genetic‐fitness payout (e.g., Simpson and Gangestad, 2000). The current work is designed to provide a coherent, quantitative model for predicting different classes of mating strategies in both males and females. Specifically, the framework developed in this paper is an elaboration of Dawkins’ (1989) quantitative assessment of different male and female mating strategies. Dawkins suggests that the prevalence of different strategies employed should be predictable in terms of evolutionary stable strategies. In the current work, a quantitative analysis predicting the prevalence of different mating strategies within each sex was conducted. The mathematical functions derived suggest that variability in the costs associated with raising offspring affects the expected prevalence of mating strategies differently for males and females. According to the present model, variability in female strategies should be less affected by changes in parental investment (PI) than variability in male strategies. Important predictions regarding male and female mating strategies across cultures are discussed.  相似文献   

17.
Abstract  Willows ( Salix spp.) are Weeds of National Significance in Australia where a large number of taxa are naturalised in temperate regions and can cause serious environmental degradation of riparian and wetland habitats. Several species are of economic or ornamental value and conflicts of interest could arise with planning their suppression. Biological control of six willow species ( S. alba L., S. cinerea L . , S. fragilis L., S. nigra Marshall, S. viminalis L., S . x  rubens Schrank) is under consideration in Australia using three approaches based on targeting different morphological structures. A rich phytophagous biota associated with Salix in their regions of origin indicate a range of organisms are available for development as biological control agents. Implementation strategies will depend on the host species targeted for biological control, their reproductive strategies, the level of control required to reduce environmental impacts and the level of conflict of interest associated with a biological control program.  相似文献   

18.
基于高通量测序的全基因组关联研究策略   总被引:1,自引:0,他引:1  
周家蓬  裴智勇  陈禹保  陈润生 《遗传》2014,36(11):1099-1111
全基因组关联研究(Genome-wide association study, GWAS)是人类复杂疾病研究的重要组成部分之一,在群体水平检测全基因组范围的遗传变异与可观测性状间的遗传关联。传统的GWAS是以芯片(Array)技术获得高密度的遗传变异,尽管硕果累累,但也存在不少问题。如:所谓的“缺失的遗传力”,即利用关联分析检测达到全基因组水平显著的遗传变异位点只能解释小部分遗传力;在某些性状上不同研究的结果一致性较弱;显著关联的遗传变异位点的功能较难解释等。高通量测序技术,也称第二代测序(Next-generation sequencing, NGS)技术,可以快速、准确地产出高通量的变异位点数据,为解决以上问题提供了可行的方案。基于NGS技术的GWAS方法(NGS-GWAS),可在一定程度上弥补传统GWAS的不足。文章对NGS-GWAS策略和方法进行了系统性调研,提出了目前较为可行的NGS-GWAS的实施策略和方法,并对NGS-GWAS如何应用于个体化医疗(Personalized medicine, PM)进行了展望。  相似文献   

19.
Transmissible spongiform encephalopathies, also known as prion-related diseases, are a group of fatal neurodegenerative disorders associated with the misfolding of the prion protein. In this article, the potential use of the principles of prion replication to develop novel therapeutic and diagnostic strategies for these devastating diseases are described.  相似文献   

20.
In this paper, different strategies to test for association in samples with related individuals designed for linkage studies are compared. Because no independent controls are available, a family-based association test and case-control tests corrected for the presence of related individuals in which unaffected relatives are used as controls were tested. When unrelated controls are available, additional strategies including selection of a single case per family considering either all families or a subset of linked families, are also considered. Analyses are performed on the simulated dataset, blind to the answers. The case-control test corrected for the presence of related individuals is the most powerful strategy to detect three loci associated with the disease under study. Using a correction factor for the case-control test performed conditional on the marker information rather than unconditional does not impact the power significantly.  相似文献   

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