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21.
Spatial variation in resources is a fundamental driver of habitat quality but the realized value of resources at any point in space may depend on the effects of conspecifics and stochastic factors, such as weather, which vary through time. We evaluated the relative and combined effects of habitat resources, weather, and conspecifics on habitat quality for ferruginous pygmy-owls (Glaucidium brasilianum) in the Sonoran Desert of northwest Mexico by monitoring reproductive output and conspecific abundance over 10 years in and around 107 territory patches. Variation in reproductive output was much greater across space than time, and although habitat resources explained a much greater proportion of that variation (0.70) than weather (0.17) or conspecifics (0.13), evidence for interactions among each of these components of the environment was strong. Relative to habitat that was persistently low in quality, high-quality habitat buffered the negative effects of conspecifics and amplified the benefits of favorable weather, but did not buffer the disadvantages of harsh weather. Moreover, the positive effects of favorable weather at low conspecific densities were offset by intraspecific competition at high densities. Although realized habitat quality declined with increasing conspecific density suggesting interference mechanisms associated with an Ideal Free Distribution, broad spatial heterogeneity in habitat quality persisted. Factors linked to food resources had positive effects on reproductive output but only where nest cavities were sufficiently abundant to mitigate the negative effects of heterospecific enemies. Annual precipitation and brooding-season temperature had strong multiplicative effects on reproductive output, which declined at increasing rates as drought and temperature increased, reflecting conditions predicted to become more frequent with climate change. Because the collective environment influences habitat quality in complex ways, integrated approaches that consider habitat resources, stochastic factors, and conspecifics are necessary to accurately assess habitat quality.  相似文献   
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The availability of monoclonal antibodies (mAbs) against the proteins of the oxidative phosphorylation chain (OXPHOS) and other mitochondrial components facilitates the analysis and ultimately the diagnosis of mitochondrially related diseases. mAbs against each of the five complexes and pyruvate dehydrogenase (PDH) are the basis of a rapid and simple immunocytochemical approach [Hanson, B.J., Capaldi, R.A., Marusich, M.F. and Sherwood, S.W., J. Histochem. Cytochem. 50 (2002) 1281-1288]. This approach can be used to detect if complexes have altered assembly in mitochondrial disease due to mutations in nuclear encoded genes, such as in Leigh's disease, or in mitochondrially encoded genes, e.g., MELAS. Other mAbs have recently been obtained that can immunocapture each of the five OXPHOS complexes, PDH and the adenine nucleotide translocase (ANT) from very small amounts of tissue such as that obtained from cell culture or needle biopsies from patients. When adapted to a 96-well plate format, these mAbs allow measurement of the specific activity of each of the mitochondrial components individually and analysis of their subunit composition and state of posttranslational modification. The immunocapture protocol should be useful not only in the analysis of genetic mitochondrial diseases but also in evaluating and ultimately diagnosing late-onset mitochondrial disorders including Parkinson's disease, Alzheimer's disease, and late-onset diabetes, which are thought to result from accumulated oxidative damage to mitochondrial proteins such as the OXPHOS chain.  相似文献   
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Conservation successes of the past several decades provide natural settings to study post-bottleneck evolutionary processes in species undergoing recovery. Here, we study the impact of demographic change on genetic diversity in parallel natural experiments of historical decline and subsequent recovery in two sympatric pinniped species in the Northwest Atlantic, the gray seal (Halichoerus grypus atlantica) and harbor seal (Phoca vitulina concolor). We compare genetic diversity at the mitochondrial control region today to diversity in archaeological specimens, which represent the populations prior to the regional bounties of the late 1800s to mid-1900s that drastically reduced population sizes and led to local extirpations. We further assess genetic diversity throughout recovery, using biological collections from ongoing long-term studies of both species. Overall, the genetic data are consistent with the historical presence of large, genetically diverse populations of pinnipeds prior to human exploitation, and suggest that gray seals were more dramatically impacted by historical bottlenecks than harbor seals in the Northwest Atlantic. Current mitochondrial diversity in both species is relatively high, and we observe little change over the past several decades during a period of roughly parallel rapid population increases. However, there remain large differences in haplotype composition between pinniped populations of pre-exploitation and today, a lasting genetic signature of historical exploitation that is likely to persist into the future.  相似文献   
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Background

Q fever is a common cause of febrile illness and community-acquired pneumonia in resource-limited settings. Coxiella burnetii, the causative pathogen, is transmitted among varied host species, but the epidemiology of the organism in Africa is poorly understood. We conducted a systematic review of C. burnetii epidemiology in Africa from a “One Health” perspective to synthesize the published data and identify knowledge gaps.

Methods/Principal Findings

We searched nine databases to identify articles relevant to four key aspects of C. burnetii epidemiology in human and animal populations in Africa: infection prevalence; disease incidence; transmission risk factors; and infection control efforts. We identified 929 unique articles, 100 of which remained after full-text review. Of these, 41 articles describing 51 studies qualified for data extraction. Animal seroprevalence studies revealed infection by C. burnetii (≤13%) among cattle except for studies in Western and Middle Africa (18–55%). Small ruminant seroprevalence ranged from 11–33%. Human seroprevalence was <8% with the exception of studies among children and in Egypt (10–32%). Close contact with camels and rural residence were associated with increased seropositivity among humans. C. burnetii infection has been associated with livestock abortion. In human cohort studies, Q fever accounted for 2–9% of febrile illness hospitalizations and 1–3% of infective endocarditis cases. We found no studies of disease incidence estimates or disease control efforts.

Conclusions/Significance

C. burnetii infection is detected in humans and in a wide range of animal species across Africa, but seroprevalence varies widely by species and location. Risk factors underlying this variability are poorly understood as is the role of C. burnetii in livestock abortion. Q fever consistently accounts for a notable proportion of undifferentiated human febrile illness and infective endocarditis in cohort studies, but incidence estimates are lacking. C. burnetii presents a real yet underappreciated threat to human and animal health throughout Africa.  相似文献   
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The developmental origins of health and disease hypothesis holds that inappropriate environmental cues in utero, a period marked by tremendous developmental sensitivity, facilitate cellular reprogramming to ultimately predispose disease in adulthood. In this review, we analyze if stress during early stages of development can affect future health. This has wide clinical importance, given that 5 million children have been conceived with assisted reproductive technologies (ART). Because the primary outcome of assisted reproduction procedures is delivery at term of a live, healthy baby, the postnatal effects occurring outside ofthe neonatal period are often overlooked. To this end, the long‐term outcome of ART is appropriately the most relevant concern of the field today. Evidence of adverse consequences is controversial. The majority of studies have concluded no obvious problems in IVF‐conceived children, although a number of isolated cases of imprinted diseases, cancers, or malformations have been reported. Given that animal studies suggest alteration of metabolic pathways following preimplantation stress, it will be of great importance to follow‐up ART individuals as they enter later stages of adult life. Birth Defects Research (Part C) 96:299–314, 2012. © 2013 Wiley Periodicals, Inc.  相似文献   
27.
Three different estimators are presented for the types of parameters present in mathematical models of animal epidemics. The estimators make use of the data collected during an epidemic, which may be limited, incomplete, or under collection on an ongoing basis. When data are being collected on an ongoing basis, the estimated parameters can be used to evaluate putative control strategies. These estimators were tested using simulated epidemics based on a spatial, discrete-time, gravity-type, stochastic mathematical model containing two parameters. Target epidemics were simulated with the model and the three estimators were implemented using various combinations of collected data to independently determine the two parameters.  相似文献   
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We examined if smallholders that immigrated to the Amazon over the last 40 years (highway-era families) and households with historical ties to the region (rubber-era families) adopt different livelihood activities and land-use/land-cover (LULC) patterns, in four communities along the Tapajós River in the Brazilian Amazon. Using quantitative data, we characterized three portfolios of livelihood activities, each associated to different LULC. Both rubber-era and highway-era families practice a wide range of activities from all portfolios; however, families that have been in the region for several generations tend to adopt traditional activities (e.g., fishing, non-timber forest product gathering and sales), while recently settled families tend to practice agrarian activities more intensively (e.g., cattle ranching, sale of non-native crops). We then draw on qualitative data to examine some of the underlying reasons for these differences. While recognizing that livelihoods are complex systems with many influential factors, we reflect on some of the overlooked drivers of livelihood and LULC choices such as knowledge, visions of development, and the immaterial value and symbolic meaning of resources. We also reflect on how they shape intended land management choices and relate to household settlement histories. The implications for regional resource-use planning and future research are mentioned.  相似文献   
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