Gametic gene flow method accounts for genomic imprinting

Findings within the last 15 years emphasize the possible role of genomic imprinting for trait expression in livestock species. In genetic evaluation, genomically imprinted traits can be treated by models with two different breeding values per animal; one accounts for the paternal and the other for the maternal expression pattern. Relative weighting factors for these breeding values were derived by a generalized version of the discounted gene flow method, which was extended to a gametic level to account for parent‐of‐origin effects. The gametic approach proved also useful for calculating the expected increase in inbreeding induced by one round of selection and its dynamics over time. The gametic gene flow method was applied to a hypothetical pig breeding programme. Relative weighting factors were higher for the paternally inherited genetic effect even in female selection paths, but depend on the breeding scheme heavily. The maximum medium‐term increase in inbreeding due to selection exceeded the long‐term increase in a range of 20–100%.     

不同剂量中波紫外线照射对鹌鹑内脏器官重量的影响

将10日龄鹌鹑300只(公、母各半)随机分成5组,每组60只(公、母各30只),以功率为15 W的中波紫外灯为紫外线光源,以每天连续照射1 h、2 h、4 h和6 h(紫外线照射剂量分别为1.4μW.h/cm2、2.8μW.h/cm2、5.6μW.h/cm2和8.4μW.h/cm2)的鹌鹑为试验组,未接受紫外线照射的鹌鹑为对照组,试验期为4周。系统比较了不同紫外线照射剂量下鹌鹑心脏、肝脏、脾脏、肺脏、肾脏、肌胃和腺胃等各内脏器官的重量。结果表明:每天照射1 h的中波紫外线(照射剂量为1.4μW.h/cm2)可显著增加心脏和肝脏的重量。     

Genetic parameters for body weights,egg traits and antibody response against Newcastle Disease Virus (NDV) vaccine among two Tanzania chicken ecotypes

Genetic parameters were estimated for production traits and primary antibody response (Ab) against Newcastle diseases virus (NDV) vaccine among two Tanzania chicken ecotypes viz. Kuchi and Tanzania Medium (Medium). Production traits studied were body weights at 8 (Bwt8), 12(Bwt12), 16(Bwt16), and 20 (Bwt20) weeks of age, age at first egg (AFE), egg number in the first 90 days after sexual maturity (EN-90), egg weight (EW), egg shell thickness (STH), and egg shape index (ESI). Heritability estimates for Bwt8, Bwt12, Bwt16, Bwt20, AFE, EN-90, EW, STH, ESI and Ab for Kuchi chicken were 0.38 ± 0.10, 0.41 ± 0.07, 0.44 ± 0.08, 0.45 ± 0.09, 0.42 ± 0.10, 0.31 ± 0.05, 0.43 ± 0.08, 0.53 ± 0.11, 0.48 ± 0.13 and 0.27 ± 0.06, respectively. Corresponding estimates for Medium ecotype were 0.39 ± 0.09, 0.43 ± 0.10, 0.42 ± 0.08, 0.43 ± 0.07, 0.52 ± 0.11, 0.32 ± 0.06, 0.50 ± 0.07, 0.61 ± 0.13, 0.52 ± 0.10 and 0.29 ± 0.05, respectively. Genetic (r _g) and phenotypic (r_p) correlations in both ecotypes were highest among body weights (i.e. r_g = 0.60 to 0.93 and r_p = 0.54 to 0.78), and were lowest (around 0.10 and below, ranging from positive to negative) among primary antibody response against NDV vaccine and production traits, and among eggshell thickness, egg shape index and other production traits. The magnitudes of heritability estimates obtained in this study indicate good prospects of improving these traits in both ecotypes through selection.     

基于证据权模型的退耕还林(草)驱动力因素分析——以陕西省吴起县为例

以2000年、2011年的Landsat TM影像为数据源,通过遥感解译和GIS空间技术集成,得到吴起县两期土地利用覆盖分类图,采用证据权模型研究吴起县154个村2000-2011年退耕还林（草）的格局演变及内在驱动机制。结果表明:11年来,吴起县耕地面积显著减少,林地、草地面积明显增加;耕地有84.6%退耕成林地、草地,其中,耕地的坡度、距离公路的距离、人均耕地面积与退耕还林（草）的分布呈正相关关系;高程与退耕还林（草）的分布呈倒U形关系;道路密度与退耕还林（草）分布呈负相关关系,但是显著程度并不明显;阴坡退耕还林（草）面积相对于阳坡面积较大;距离农村道路的距离对退耕还林（草）的分布没有显著的影响。气象数据相关变量中,年均相对湿度与退耕还林（草）分布呈倒U形关系,20-20时平均年降水量与退耕还林（草）分布呈正相关关系。     

Development of economic forest tree breeding objectives: review of existing methodology and discussion of its application in Swedish conditions

Abstract

Genetic selection in forest tree breeding requires multiple traits to be considered simultaneously. Based on an economic breeding objective, traits are weighted according to their economic importance to create an index used for selection. Economic breeding objectives have mainly been developed in animal breeding and have only recently been applied to forest tree breeding. A review of the general methodology highlights the decisions associated with developing economic breeding objectives and their effects. Furthermore, studies concerning economic forest tree breeding objectives provide a bulk of knowledge and practical experience for fast growing, short rotation species. We have identified and discussed challenges when applying this methodology in Swedish tree breeding. Major challenges are: (1) managing the uncertainty of future industrial uses of wood and industrial processing, originating from long rotations; (2) various issues associated with having a production system describing an entire nation; (3) the size and effects of the discount rate; (4) developing models capable of representing genetic changes in the complex and dynamic system of growing and harvesting trees. We believe that these challenges must be tackled by a joint multi-disciplinary effort, involving stakeholders and researchers in several areas (e.g. forest genetics, economics, wood engineering), to make significant progress.     

Combination Forecasting Models Using Regression Analysis Method

Using regression analysis method,the methods for solving the weights of combination forecasting model(CFM) are proposed. At first, the linear regress CFM are presented based on the least absolute criteria and least square criteria. Then the weights can be evaluated using the least square princinple. Because the objective function of CFM based on least absolute criteria is non differential, the traditional programming methods can not solve it. So the least square method with the modified weights is proposed to solve this problem. At the same time, methods for solving CFM is given with the aim of minimizing sum of percentage error absolutes. From many cases, the results show that the forecasting precision of CFM is very high and the effect of regression is remarkable.     

Semi‐synthetic diet versus diet using natural ingredients—Comparative study in female Golden Syrian hamsters

Semi‐synthetic diets (SSD) are recommended and are widely used to carry out experiments in rodents. However, in our experiments planned to carry out generation studies in female Golden Syrian hamsters using semi‐synthetic diets, it was observed that the hamsters did not conceive as a result of decreased food intake. In this paper, we present the effects of both semi‐synthetic diets and natural source diets (NSD) on food intake, body weight and reproductive performance of this species. Four‐week‐old female hamsters were equally divided into 3 groups and initially acclimatized for 2 weeks on natural chow diet (NCD). Thereafter, they were fed either control diet, high fat diet (HFD) or low protein diet (LPD) based on semi‐synthetic/natural source ingredients until 12 weeks. Daily food intake and weekly body weights were monitored. Hamsters were kept for mating for about 2 weeks from 10th week onwards, during which the pregnancy confirmation test was done using standard vaginal smear examination. In all the groups fed SSD, the food intake was very poor, hamsters lost body weight and did not conceive, thus preventing us from carrying out further experiments. Hamsters fed NCD/NSD ingested more than twice as much as hamsters fed SSD (7–8 g/day/hamster against 3 g/day/hamster on average respectively). Based on the results of the current research, we conclude that the routinely used semi‐synthetic diet is not suitable for carrying out studies in female hamsters. We suggest that scientists must also consider the unusual biological characteristics of a given species besides other biological factors. It is therefore critical to select appropriate biological models and diets that provide optimal sensitivity and specificity to accomplish the research objectives.     

Selection of Objective Traits and Estimation of Economic Weights for Chinese Simmental Beef Cattle

In order to breed a beef line in Chinese Simmental cattle,this research defined breeding objective traits and selected traits according to real breeding condition of Chinese Simmental beef cattle.Using the balance method to calculate the marginal benefit of each objective trait and getting the corresponding economic weight of breeding objective traits through the standard value of the error corrected marginal benefit of breeding objective traits.The results showed that breeding objective traits mainly included growth traits (including weaning weight,fattening daily gain,18th month weight),carcass traits (including carcass quality,dressing percentage,pure meat percentage) as well as reproductive traits (including age at first calving,calving interval,stay group time).In the current market and production conditions,the marginal benefit of the breeding objective traits were 17.93 yuan/kg,16.2 yuan/kg,7.17 yuan/kg,297.99 yuan/grade,497.82 yuan/%,594.46 yuan/%,-3.62 yuan/d,-26.55 yuan/d and 232.75 yuan/y,respectively,and the ratio of relative economic weights of three kinds of traits was 31.49%:15.86%:52.65%,similar to 2:1:3,and reproductive traits occupied larger economic weight,was better than growth traits and carcass traits.The results indicated that reproductive traits played an important role in the process of breeding in Chinese Simmental beef cattle,and we needed to strengthen the selection of reproductive traits.     

内梅罗指数法在环境质量评价中的适用性与修正原则

为研究内梅罗指数法在环境要素质量评价中的适用性及确定其修正原则,将方法的计算公式进行了数学推导。结果表明:典型内梅罗指数法的计算公式可变换为线性表达式,其斜率和截距分别为最大值(F_(j,max))和算术平均值(F_(j,ave))的权重系数;随着F_(j,max)与F_(j,ave)比值的增大,F_(j,max)权重增大,F_(j,ave)权重减小。参评污染因子数量(n)对方法的评分结果具有重要影响,典型内梅罗指数法更适用于区域中目的性和指向性较明确或总体污染程度较轻的环境要素质量评价。为提高方法的适用性,确定了2种修正内梅罗指数法的划分原则,Ⅰ型和Ⅱ型修正内梅罗指数法分别以n和F_(j,max)/F_(j,ave)等于5作为划分结点,其中:Ⅰ型修正内梅罗指数法倾向于参评因子不多、评价目的性和指向性较强的环境要素质量评价;Ⅱ型修正内梅罗指数法是对Ⅰ型修正内梅罗指数法的拓展和延伸,更适用于多因子综合性质量评价。由内梅罗指数法线性表达式的数学内涵可知,在n或F_(j,max)/F_(j,ave)≤5时,方法可不作修正,此时并不影响评价结果的客观性和准确性。     

基于融合权重的云模型在西昌某地区地下水水质评价中的应用

准确的评价地下水质量是地区居民饮水安全的重要保证。针对地下水水质评价中的模糊性和随机性,考虑到评价过程中权重的重要性,建立基于AHP-CRITIC博弈论组合赋权的云模型水质评价体系,结合西昌市某地区进行实例对比分析,结果表明该评价体系具备实用性。同时,针对评价过程中所发现的问题,即单一超标污染物受到其他指标极小值的影响导致正态云模型评价结果出现失真,提出在云特征参数选取过程中加入各项指标实测数据值,主观消除评价结果误差性。