The impact of truncating data on the predictive ability for single‐step genomic best linear unbiased prediction          下载免费PDF全文

Jeremy T. Howard  Tom A. Rathje  Caitlyn E. Bruns  Danielle F. Wilson‐Wells  Stephen D. Kachman  Matthew L. Spangler 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2018,135(4):251-262

Simulated and swine industry data sets were utilized to assess the impact of removing older data on the predictive ability of selection candidate estimated breeding values (EBV) when using single‐step genomic best linear unbiased prediction (ssGBLUP). Simulated data included thirty replicates designed to mimic the structure of swine data sets. For the simulated data, varying amounts of data were truncated based on the number of ancestral generations back from the selection candidates. The swine data sets consisted of phenotypic and genotypic records for three traits across two breeds on animals born from 2003 to 2017. Phenotypes and genotypes were iteratively removed 1 year at a time based on the year an animal was born. For the swine data sets, correlations between corrected phenotypes (Cp) and EBV were used to evaluate the predictive ability on young animals born in 2016–2017. In the simulated data set, keeping data two generations back or greater resulted in no statistical difference (p‐value > 0.05) in the reduction in the true breeding value at generation 15 compared to utilizing all available data. Across swine data sets, removing phenotypes from animals born prior to 2011 resulted in a negligible or a slight numerical increase in the correlation between Cp and EBV. Truncating data is a method to alleviate computational issues without negatively impacting the predictive ability of selection candidate EBV.  相似文献   

Investigation and clinical application of a novel axial pattern flap for nasal and facial reconstruction in the dog     

Yates G  Landon B  Edwards G 《Australian veterinary journal》2007,85(3):113-118

OBJECTIVE: To describe the vascular supply to a facial skin flap based at the commissure of the lip in the dog and report on its use in four dogs. STUDY DESIGN: Experimental and prospective clinical study. Animals Five canine cadavers and four client-owned dogs. METHODS: In the cadavers, the ventral aspect of the zygomatic arch, the ventral margin of the caudal mandible and the wing of the atlas were marked as anatomical boundaries of a skin flap that was elevated from the subcutaneous tissues to the level of the medial canthus of the eye. Methylene blue dye and barium sulphate solution were independently infused through a common carotid (three dogs) or facial artery (two dogs) catheter. Distribution of dye throughout the harvested skin was assessed subjectively. After contrast infusion the flap was excised and radiographed. The technique was used to reconstruct large facial or nasal defects in four dogs after tumour or skin lesion excision. RESULTS: Cadaver dissections and contrast studies clearly demonstrated three direct cutaneous arteries, the superior and inferior labial arteries and the angularis oris artery, arborising within the base of the flap. A separate direct cutaneous branch of the angularis oris artery was identified. An arterial plexus was identified within the distal flap, within which this artery communicates with the transverse facial artery and a cutaneous branch of the masseteric artery. Dye infusion caused discolouration of the elevated skin and vasculature within the flap. The flap survived in all clinical cases with marginal distal necrosis in one dog. CONCLUSIONS: The complex facial flap described is perfused by three direct cutaneous arteries and functions reliably in clinical cases.  相似文献   

苏州市不同区域水稻籽粒重金属积累特征与健康风险评价     

齐雁冰  黄标  杨玉峰  Darilek J L  赵永存  孙维侠  王志刚 《农业环境保护》2010,(4):659-665

以苏州市7个县市的水稻籽粒为研究对象,在2006年采集的449份水稻籽粒样品的基础上,分析了稻米中Cu、Pb、Cd、Cr和Zn的积累特征,并评价了样品的健康风险。结果显示,苏州市水稻籽粒重金属积累平均含量均不超标,但水稻籽粒Pb存在29．49％的样点超标率,Cu、Cd和Cr的超标样点一般在4个以下。单因子污染指数评价结果显示,水稻籽粒重金属元素污染指数高低顺序为Pb＞Cr＞Cu、Zn＞Cd,其中昆山和吴江水稻籽粒受到Pb的轻度污染。综合污染指数评价表明,水稻籽粒重金属污染处于警戒线级别,且水稻籽粒的污染是由于Pb的积累量较高引起的,其中太仓和张家港两市水稻籽粒属于安全等级,昆山、吴中、相城和常熟处于警戒线等级,吴江风险较高。暴露风险评价结果显示,研究区存在水稻籽粒Cr暴露风险,而水稻籽粒Pb仅在个别县市暴露风险高,整体风险并不高。  相似文献   

基于稳健统计学确定高潜在污染土壤Cu、Pb基线值     

王志刚  赵永存  孙维侠  黄标  邵学新  Jeremy L. Darilek 《土壤学报》2011,48(2):246-254

土壤重金属基线值的确定对于评价重金属积累现状具有重要意义。在存在人为污染的情况下,土壤重金属数据经常强烈地偏离正态分布和对数正态分布,影响统计分析结果的可信度,而稳健统计方法可以降低离群值对统计分析结果的影响。本研究以张家港为研究区域,采用稳健回归方法,建立表层和底层土壤Cu、Pb的回归关系,通过底层土壤Cu、Pb含量计算表层土壤Cu、Pb基线值,并对土壤Cu、Pb积累状况进行评价。结果表明,稳健回归方法确定的表层土壤Cu、Pb基线值可以反映出不同样点间,土壤Cu、Pb背景含量的自然变异。与稳健统计学方法相比,使用国家土壤环境质量标准值,或大区域(江苏省)的土壤背景值,评价自然背景本身存在变异区域的土壤重金属积累状况时,可能会产生较大的误差。  相似文献   

基于稳健统计学确定高潜在污染土壤Cu、Pb基线值     

王志刚  赵永存  孙维侠  黄标  邵学新  Jeremy L. Darilek 《土壤学报》2010,47(6)

土壤重金属基线值的确定对于评价重金属积累现状具有重要意义。在存在人为污染的情况下,土壤重金属数据经常强烈地偏离正态分布和对数正态分布,影响统计分析结果的可信度,而稳健统计方法可以降低离群值对统计分析结果的影响。本研究以张家港为研究区域,采用稳健回归方法,建立表层和底层土壤Cu、Pb的回归关系,通过底层土壤Cu、Pb含量计算表层土壤Cu、Pb基线值,并对土壤Cu、Pb积累状况进行评价。结果表明,稳健回归方法确定的表层土壤Cu、Pb基线值可以反映出不同样点间,土壤Cu、Pb背景含量的自然变异。与稳健统计学方法相比,使用国家土壤环境质量标准值,或大区域（江苏省）的土壤背景值,评价自然背景本身存在变异区域的土壤重金属积累状况时,可能会产生较大的误差。  相似文献   

Non-random patterns of vegetation clearing and potential biases in studies of habitat area effects     

Jeremy S. Simmonds  Berndt J. van Rensburg  Martine Maron 《Landscape Ecology》2017,32(4):729-743

  相似文献   

First transgenic trait for control of plant bugs and thrips in cotton     

Waseem Akbar  Anilkumar Gowda  Jeffrey E Ahrens  Jason W Stelzer  Robert S Brown  Scott L Bollman  John T Greenplate  Jeffrey Gore  Angus L Catchot  Gus Lorenz  Scott D Stewart  David L Kerns  Jeremy K Greene  Michael D Toews  David A Herbert  Dominic D Reisig  Gregory A Sword  Peter C Ellsworth  Larry D Godfrey  Thomas L Clark 《Pest management science》2019,75(3):867-877

  相似文献   

A new framework of spatial targeting for single-species conservation planning     

Burgess  Malcolm  Gregory  Richard  Wilson  Jeremy  Gillings  Simon  Evans  Andy  Chisholm  Kenna  Southern  Adrian  Eaton  Mark 《Landscape Ecology》2019,34(12):2765-2778

Context

Organisations acting to conserve and protect species across large spatial scales prioritise to optimise use of resources. Spatial conservation prioritization tools typically focus on identifying areas containing species groups of interest, with few tools used to identify the best areas for single-species conservation, in particular, to conserve currently widespread but declining species.

Objective

A single-species prioritization framework, based on temporal and spatial patterns of occupancy and abundance, was developed to spatially prioritize conservation action for widespread species by identifying smaller areas to work within to achieve predefined conservation objectives.

Methods

We demonstrate our approach for 29 widespread bird species in the UK, using breeding bird atlas data from two periods to define distribution, relative abundance and change in relative abundance. We selected occupied 10-km squares with abundance trends that matched species conservation objectives relating to maintaining or increasing population size or range, and then identified spatial clusters of squares for each objective using a Getis-Ord-Gi* or near neighbour analysis.

Results

For each species, the framework identified clusters of 20-km squares that enabled us to identify small areas in which species recovery action could be prioritized.

Conclusions

Our approach identified a proportion of species’ ranges to prioritize for species recovery. This approach is a relatively quick process that can be used to inform single-species conservation for any taxa if sufficiently fine-scale occupancy and abundance information is available for two or more time periods. This is a relatively simple first step for planning single-species focussed conservation to help optimise resource use.

  相似文献   

Evidence from tag recapture experiments that fish learn to avoid fishing gear     

David J. Gilbert  Jeremy R. McKenzie  Nicholas M. Davies 《Journal of Agricultural, Biological & Environmental Statistics》2001,6(2):281-291

We found evidence that tagging induced trap shyness in snapper (Pagrus auratus), i.e., tagged fish had a reduced probability of recapture by the method by which they had originally been caught. Tagging experiments in 1985 and 1994 involving single release over a short period and single recapture were conducted on a closed population (SNA 1: East Northland-Hauraki Gulf-Bay of Plenty). Initial capture was by trawling and by line fishing, while recapture over an extended period included other methods. A test for trap shyness that removed the possible effects of spatial and fish size heterogeneity gave a significant result for both years. The data suggested that the trap shyness effect might have been smaller for trawl-released fish than for line-released fish. However, we estimated a single trap shyness factor (0.71). There was also some evidence for attenuation of trap shyness over time.  相似文献   

Spatiotemporal Distribution of Two Euschistus spp. Stink Bugs (Hemiptera: Pentatomidae) in Southeastern Farmscapes     

Erin E Grabarczyk  Russell F Mizell  III  Jeremy K Greene  Gary A Herzog  P Glynn Tillman  Ted E Cottrell 《Journal of insect science (Online)》2022,22(1)

Stink bugs (Hemiptera: Pentatomidae) are ubiquitous, cryptic, phytophagous pests that are found in many crops. In agroecosystems, individuals disperse from adjacent noncrop hosts and tend to aggregate or cluster within fields. In this study, we characterized the distribution of Euschistus servus (Say) and Euschistus tristigmus (Say) (Hemiptera: Pentatomidae) over 2 yr at three southeastern United States farmscapes. Stink bugs were captured in pheromone-baited traps, and Spatial Analysis by Distance Indices (SADIE) used to identify the location of significant aggregations by habitat type and season. Euschistus servus adults were more likely to be captured in pecan orchards, cotton, other crops, or unmanaged habitats than in woodland habitats. Significant aggregations of E. servus were detected in a variety of habitats including pecan, corn, cotton, peanut, and tobacco, as well as fallow and hay fields, pastures, and hedgerows. Fewer adult E. tristigmus were captured than E. servus adults, and E. tristigmus adults were typically trapped and aggregated in woodland habitats. The resulting data provide an important understanding regarding the seasonal movement and relative abundance levels of stink bug populations, which are critical to the development of integrated pest management strategies.  相似文献