共查询到20条相似文献，搜索用时 0 毫秒
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从2013年1月开始欧盟将实施新的保护试验用动物指令2010/63/EU,新指令与旧指点令相比在涉及动物福利和3R原则的许多条款上做了完善,体现了国际社会对实验动物使用和管理的最新理念。欧盟保护实验动物法规的变迁,以及适应社会形势和科技进步做出的调整,对于当前中国实验动物实现规范化管理,融入国际实验动物科学发展主流理念具有重要借鉴意义。对指令条款的理解也有助于推动实验动物行业参与国际竞争、外包服务和对外贸易中发挥专业作用。 相似文献
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Epistasis refers to gene interaction effect involving two or more genes. Statistical methods for mapping quantitative trait loci (QTL) with epistasis effects have become available recently. However, little is known about the statistical power and sample size requirements for mapping epistatic QTL using genetic markers. In this study, we developed analytical formulae to calculate the statistical power and sample requirement for detecting each epistasis effect under the F-2 design based on crossing inbred lines. Assuming two unlinked interactive QTL and the same absolute value for all epistasis effects, the heritability of additive × additive (a × a) effect is twice as large as that of additive × dominance (a × d) or dominance × additive (d × a) effect, and is four times as large as that of dominance × dominance (d × d) effect. Consequently, among the four types of epistasis effects involving two loci, ''a × a'' effect is the easiest to detect whereas ''d × d'' effect is the most difficult to detect. The statistical power for detecting ''a × a'' effect is similar to that for detecting dominance effect of a single QTL. The sample size requirements for detecting ''a × d'', ''d × a'' and ''d × d'' are highly sensitive to increased distance between the markers and the interacting QTLs. Therefore, using dense marker coverage is critical to detecting those effects. 相似文献
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Dawkins MS 《Zoology (Jena, Germany)》2003,106(4):383-387
A central issue in animal welfare research is how to assess the welfare state of animals objectively and scientifically. I argue that this issue can be approached by asking two key questions: 1) is the animal physically healthy and 2) does the animal have what it wants? Behaviour is used to answer both of these questions. In the assessment of physical health, it can be used for clinical and pre-clinical diagnosis. In the assessment of what animals want, it has a major role through choice and preference testing. It is particularly important that applied ethologists develop methods for assessing welfare in situ--in the places where concern for animal welfare is greatest such as on farms and in zoos. 相似文献
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H. E. Walsh M. G. Kidd T. Moum V. L. Friesen 《Evolution; international journal of organic evolution》1999,53(3):932-937
Although phylogenetic hypotheses can provide insights into mechanisms of evolution, their utility is limited by our inability to differentiate simultaneous speciation events (hard polytomies) from rapid cladogenesis (soft polytomies). In the present paper, we tested the potential for statistical power analysis to differentiate between hard and soft polytomies in molecular phytogenies. Classical power analysis typically is used a priori to determine the sample size required to detect a particular effect size at a particular level of significance (a) with a certain power (1 – β). A posteriori, power analysis is used to infer whether failure to reject a null hypothesis results from lack of an effect or from insufficient data (i.e., low power). We adapted this approach to molecular data to infer whether polytomies result from simultaneous branching events or from insufficient sequence information. We then used this approach to determine the amount of sequence data (sample size) required to detect a positive branch length (effect size). A worked example is provided based on the auklets (Charadriiformes: Alcidae), a group of seabirds among which relationships are represented by a polytomy, despite analyses of over 3000 bp of sequence data. We demonstrate the calculation of effect sizes and sample sizes from sequence data using a normal curve test for difference of a proportion from an expected value and a t-test for a difference of a mean from an expected value. Power analyses indicated that the data for the auklets should be sufficient to differentiate speciation events that occurred at least 100,000 yr apart (the duration of the shortest glacial and interglacial events of the Pleistocene), 2.6 million years ago. 相似文献
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Sandra Strong Jennifer Federico Ron Banks Cathy Williams 《Journal of applied animal welfare science : JAAWS》2019,22(3):267-278
Companion-animal hoarding is a significant problem in the United States and internationally. Hoarding situations can incubate for years before a case is reported to law enforcement or animal control agencies. According to a survey by Gary Patronek, animal control agencies have estimated there are approximately 3000 reportable cases of animal hoarding annually in the United States. Animal hoarding cases vary in size from fewer than 20 animals to hundreds of animals. Every case of animal hoarding results in suboptimal animal welfare. Wake County, North Carolina, developed a proactive plan for addressing companion-animal hoarding that implemented a team approach to assist animals at risk, hold people accountable, address the mental health component of this problem, and create a more humane community. The plan involved animal control officers, crisis intervention counselors, law enforcement officers, veterinarians, veterinary technicians, and animal rescue partners. This intervention strategy was implemented in 2015, and cases were tracked to document animal outcomes. The conclusion of this experience is that a diverse team approach can best address the animal and human welfare challenges and the environmental concerns associated with animal hoarding. 相似文献
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Oliver Selmoni Elia Vajana Annie Guillaume Estelle Rochat Stphane Joost 《Molecular ecology resources》2020,20(1):154-169
An increasing number of studies are using landscape genomics to investigate local adaptation in wild and domestic populations. Implementation of this approach requires the sampling phase to consider the complexity of environmental settings and the burden of logistical constraints. These important aspects are often underestimated in the literature dedicated to sampling strategies. In this study, we computed simulated genomic data sets to run against actual environmental data in order to trial landscape genomics experiments under distinct sampling strategies. These strategies differed by design approach (to enhance environmental and/or geographical representativeness at study sites), number of sampling locations and sample sizes. We then evaluated how these elements affected statistical performances (power and false discoveries) under two antithetical demographic scenarios. Our results highlight the importance of selecting an appropriate sample size, which should be modified based on the demographic characteristics of the studied population. For species with limited dispersal, sample sizes above 200 units are generally sufficient to detect most adaptive signals, while in random mating populations this threshold should be increased to 400 units. Furthermore, we describe a design approach that maximizes both environmental and geographical representativeness of sampling sites and show how it systematically outperforms random or regular sampling schemes. Finally, we show that although having more sampling locations (between 40 and 50 sites) increase statistical power and reduce false discovery rate, similar results can be achieved with a moderate number of sites (20 sites). Overall, this study provides valuable guidelines for optimizing sampling strategies for landscape genomics experiments. 相似文献
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Katherine A. Leighty Joseph Soltis Christina M. Wesolek Anne Savage Jill Mellen John Lehnhardt 《Zoo biology》2009,28(1):16-28
The movements of elephants in captivity have been an issue of concern for animal welfare activists and zoological professionals alike in recent years. In order to fully understand how movement rates reflect animal welfare, we must first determine the exact distances these animals move in the captive environment. We outfitted seven adult female African elephants (Loxodonta africana) at Disney's Animal Kingdom with collar-mounted global positioning recording systems to document their movement rates while housed in outdoor guest viewing habitats. Further, we conducted preliminary analyses to address potential factors impacting movement rates including body size, temperature, enclosure size, and social grouping complexity. We found that our elephants moved at an average rate of 0.409±0.007 km/hr during the 9-hr data collection periods. This rate translates to an average of 3.68 km traveled during the observation periods, at a rate comparable to that observed in the wild. Although movement rate did not have a significant relationship with an individual's body size in this herd, the movements of four females demonstrated a significant positive correlation with temperature. Further, females in our largest social group demonstrated a significant increase in movement rates when residing in larger enclosures. We also present preliminary evidence suggesting that increased social group complexity, including the presence of infants in the herd, may be associated with increased walking rates, whereas factors such as reproductive and social status may constrain movements. Zoo Biol 28:16–28, 2009. © 2008 Wiley-Liss, Inc. 相似文献
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Austin Leeds Julie Good Mandi W. Schook Patricia M. Dennis Tara S. Stoinski Mark A. Willis Kristen E. Lukas 《Zoo biology》2020,39(1):51-55
Positive reinforcement training (PRT) is associated with increases in species-typical behavior and decreases in stereotypic and abnormal behavior in participating animals. Physiological changes following PRT, for example, increases in oxytocin (OXT) and/or decreases in cortisol (CORT), may facilitate these behavioral changes. This study evaluated salivary OXT and salivary CORT concentrations in two adult male western lowland gorillas (Gorilla gorilla gorilla) following PRT with their primary animal care staff. Following PRT, no change in OXT was observed. CORT decreased in one subject following PRT. Changes in endogenous OXT are related to affiliative interactions and interact with strongly bonded conspecifics. PRT may not activate the oxytocinergic system because PRT is not a species-specific affiliative interaction and/or animal care staff are not viewed as conspecifics. Regardless, PRT may still be viewed as a positive interaction resulting in stress reduction via a decrease in CORT. Relationships are unique, thus these results only apply to these two gorillas and one animal caregiver. Larger population-level studies are needed to understand overall trends in human–animal interactions, and ultimately human–animal relationships. Further evaluation of physiological changes following human–animal interactions should be informative for understanding the human–animal relationship in zoos. 相似文献
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Michael Hutchins 《Zoo biology》1990,9(6):447-460
Biological materials obtained during routine veterinary treatment and necropsies on zoo and aquarium animals provide opportunities to study a wide variety of phenomena, many of which have important implications for wildlife conservation and captive animal management. Collection and shipment of biological materials require extensive coordination, and few zoological institutions have developed detailed, standardized protocols to facilitate these efforts. The value of using biological materials is reviewed and a set of policies and guidelines are outlined for their collection, preservation, and shipment. Several related issues are discussed, including health hazards and liability issues, permit requirements, and animal welfare considerations. 相似文献
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The increasing interest in subpopulation analysis has led to the development of various new trial designs and analysis methods in the fields of personalized medicine and targeted therapies. In this paper, subpopulations are defined in terms of an accumulation of disjoint population subsets and will therefore be called composite populations. The proposed trial design is applicable to any set of composite populations, considering normally distributed endpoints and random baseline covariates. Treatment effects for composite populations are tested by combining p-values, calculated on the subset levels, using the inverse normal combination function to generate test statistics for those composite populations while the closed testing procedure accounts for multiple testing. Critical boundaries for intersection hypothesis tests are derived using multivariate normal distributions, reflecting the joint distribution of composite population test statistics given no treatment effect exists. For sample size calculation and sample size, recalculation multivariate normal distributions are derived which describe the joint distribution of composite population test statistics under an assumed alternative hypothesis. Simulations demonstrate the absence of any practical relevant inflation of the type I error rate. The target power after sample size recalculation is typically met or close to being met. 相似文献
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Xin Wang Tu Xu Sheng Zhong Yijie Zhou Lu Cui 《Biometrical journal. Biometrische Zeitschrift》2019,61(3):769-778
In clinical trials, sample size reestimation is a useful strategy for mitigating the risk of uncertainty in design assumptions and ensuring sufficient power for the final analysis. In particular, sample size reestimation based on unblinded interim effect size can often lead to sample size increase, and statistical adjustment is usually needed for the final analysis to ensure that type I error rate is appropriately controlled. In current literature, sample size reestimation and corresponding type I error control are discussed in the context of maintaining the original randomization ratio across treatment groups, which we refer to as “proportional increase.” In practice, not all studies are designed based on an optimal randomization ratio due to practical reasons. In such cases, when sample size is to be increased, it is more efficient to allocate the additional subjects such that the randomization ratio is brought closer to an optimal ratio. In this research, we propose an adaptive randomization ratio change when sample size increase is warranted. We refer to this strategy as “nonproportional increase,” as the number of subjects increased in each treatment group is no longer proportional to the original randomization ratio. The proposed method boosts power not only through the increase of the sample size, but also via efficient allocation of the additional subjects. The control of type I error rate is shown analytically. Simulations are performed to illustrate the theoretical results. 相似文献
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Research examining the effects of electromagnetic fields (EMFs) on human performance and physiology has produced inconsistent results; this might be attributable to low statistical power. Statistical power refers to the probability of obtaining a statistically significant result, given the fact that a real effect exists. The results of a survey of published investigations of the effects of EMFs on human performance and physiology show that statistical power levels are very low, ranging from a mean of.08 for small effect sizes to .46 for large effect sizes. Implications of these findings for the interpretation of results are discussed along with suggestions for increasing statistical power. © 1996 Wiley-Liss, Inc. 相似文献
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《Animal : an international journal of animal bioscience》2016,10(1):142-149
Production systems for fattening pigs have been characterized over the last 2 decades by rising farm sizes coupled with increasing group sizes. These developments resulted in a serious public discussion regarding animal welfare and health in these intensive production systems. Even though large farm and group sizes came under severe criticism, it is still unknown whether these factors indeed negatively affect animal welfare. Therefore, the aim of this study was to assess the effect of group size (<15 v. 15 to 30 v. >30 pigs/pen) on various animal-based measures of the Welfare Quality® protocol for growing pigs under conventional fattening conditions. A total of 60 conventional pig fattening farms with different group sizes in Germany were included. Moderate bursitis (35%) was found as the most prevalent indicator of welfare-related problems, while its prevalence increased with age during the fattening period. However, differences between group sizes were not detected (P>0.05). The prevalence of moderately soiled bodies increased from 9.7% at the start to 14.2% at the end of the fattening period, whereas large pens showed a higher prevalence (15.8%) than small pens (10.4%; P<0.05). With increasing group size, the incidence of moderate wounds with 8.5% and 11.3% in small- and medium-sized pens, respectively, was lower (P<0.05) than in large-sized ones (16.3%). Contrary to bursitis and dirtiness, its prevalence decreased during the fattening period. Moderate manure was less often found in pigs fed by a dry feeder than in those fed by a liquid feeding system (P<0.05). The human–animal relationship was improved in large in comparison to small groups. On the contrary, negative social behaviour was found more often in large groups. Exploration of enrichment material decreased with increasing live weight. Given that all animals were tail-docked, tail biting was observed at a very low rate of 1.9%. In conclusion, the results indicate that BW and feeding system are determining factors for the welfare status, while group size was not proved to affect the welfare level under the studied conditions of pig fattening. 相似文献