坡耕地地表糙度的量测与计算

在回顾了地表糙度的测量和计算方法后,经实验证实,Brough D L,Linden D R和Van Doren D M等人提出的糙度测量和计算方法,均能满足黄土高原坡耕地人为耕作管理形成的微地形特征的研究需求。     

Selection on multiple QTL with control of gene diversity and inbreeding for long-term benefit

The purpose of this study was to develop and investigate selection strategies that aim at maximizing long-term genetic response while conserving gene diversity and controlling inbreeding in populations of limited effective size, assuming complete knowledge of all genes affecting a quantitative trait. Three selection strategies were proposed to select on 100 quantitative trait loci (QTL) and compared with truncation selection on breeding value. Alternative selection strategies aimed at maximizing the average breeding value of parents with a penalty on (1) the number of unfavourable QTL genotypes among parents (OS-I), (2) the negative of the logarithm of the frequency of the favourable allele at each QTL among parents (OS-II), and (3) the average pedigree relationship among parents (OS-III). When all QTL and their effects were known, the strategies examined were able to obtain extra long-term responses, conserve QTL diversity and reduce inbreeding, compared with truncation selection. Strategy OS-II was the most effective in conserving QTL diversity and OS-III in reducing inbreeding. By changing the magnitude of the penalties applied, the impact on long-term response, inbreeding and diversity can be controlled. Extra long-term responses over truncation selection of OS-I and OS-II were even greater when effects of QTL were estimated rather than assumed known, indicating the applicability of results to practical strategies for marker-assisted selection. Extra responses are expected to be reduced for larger population sizes.     

二次回归正交旋转组合设计优化21～42日龄肉仔鸡胆碱和蛋氨酸需要量

本试验以低胆碱、低蛋氨酸饲粮为基础饲粮,通过两因子二次回归正交旋转组合设计,对21～42日龄肉仔鸡胆碱和蛋氨酸需要量进行研究.试验选用21日龄爱拔益加(AA)肉仔鸡480只,随机分为12个组,其中1～8组为试验组,9～12组为中心组,每组4个重复,每个重复10只鸡,公母各占1/2.分别以胆碱和蛋氨酸为自变量,以反映肉仔鸡生长性能和屠宰性能的各项指标为因变量拟合回归方程,估计21 ～ 42日龄肉仔鸡胆碱和蛋氨酸的需要量.试验期21 d.结果表明:胆碱和蛋氨酸水平对21～42日龄肉仔鸡的平均日采食量、料重比、腹脂率和肝脂率有显著影响(P＜0.05).当胆碱水平在860～1 120mg/kg时,肉仔鸡平均日采食量随着蛋氨酸水平的增加而升高,蛋氨酸水平增至0.40％后,继续增加对平均日采食量的改善作用不明显;蛋氨酸水平在0.35％～0.42％,胆碱水平在860 ～1 120mg/kg时,肉仔鸡的料重比达到最低值;蛋氨酸水平在0.30％～0.47％时,随着胆碱水平的增加肉仔鸡腹脂率呈下降趋势;当蛋氨酸水平在0.30％ ～0.40％,胆碱水平在1 000 ～1 400mg/kg时,肉仔鸡肝脂率随着胆碱水平的增加和蛋氨酸水平的降低呈下降趋势.在本试验条件下,当胆碱水平为990 ～1 030mg/kg,蛋氨酸水平为0.40％ ～0.43％时,肉仔鸡可达到最佳生长性能;当胆碱水平为1 780～1 880 mg/kg,蛋氨酸水平为0.37％ ～0.38％时,肉仔鸡可达到最佳屠宰性能.     

假苍耳的地理分布及潜在适生区预测

外来入侵植物假苍耳在中国东北部地区快速蔓延,威胁自然生态系统的结构并对人们的健康产生危害。本研究通过野外调查获得假苍耳在东北地区的分布范围,采用Maxent模型软件对假苍耳在我国及世界的潜在适生区进行预测,运用ArcGIS软件中的自然间断点分级法进行适生等级分类,ROC曲线评价Maxent模型预测的准确性,并结合刀切法及环境变量反应曲线判断分析影响假苍耳分布的主要环境变量。结果表明,假苍耳的适生区较广,扩散范围可能继续增大。我国的华北地区、东北地区、华东地区、华中地区、西南地区、西北地区均存在适生区,高度适生区主要分布在我国的黑龙江省、吉林省、辽宁省、内蒙古自治区、山西省、陕西省、河南省、河北省、山东省、北京市、天津市、新疆维吾尔族自治区。世界范围内除南极洲外均存在假苍耳的适生区,高度适生区主要在北美洲的加拿大和美国,非洲的摩洛哥,欧洲的西班牙、克罗地亚、匈牙利、斯洛伐克、波黑、塞尔维亚、马其顿、保加利亚、格鲁吉亚、亚美尼亚和阿塞拜疆,亚洲的土耳其、伊朗、哈萨克斯坦、吉尔吉斯斯坦、塔吉克斯坦、中国、朝鲜、韩国和日本。上述适生区预测显示出假苍耳适宜生长在年均温度较高,最冷月份最低温和最冷季度平均温度较低的中纬度地区。     

抑制USP7活性对鸡抗沙门菌感染的影响

本研究旨在阐明去泛素酶USP7对雏鸡抵抗鼠伤寒沙门菌感染的影响。选用3日龄的白来航鸡40只,随机分为2组,每组20只,隔天腹腔注射USP7抑制剂P5091或对照溶剂,连续注射5次,待最后一次注射结束后第4天,对雏鸡人工口服感染鼠伤寒沙门菌,感染24 h后,采集样品,RT-qPCR检测IL-1β、IL-8、TNFα以及NF-κB的mRNA表达,平板涂布法检测雏鸡肝载菌量,H&E染色观察肝和肺的炎症状况。结果表明,P5091抑制USP7活性后,转录因子NF-κB mRNA水平显著降低,并且下游细胞因子IL-1β、IL-8以及TNF-α的表达均下调,雏鸡载菌量下降,H&E染色显示肝与肺炎症反应加剧。综上表明,USP7可能在机体抗沙门菌感染方面起重要作用。     

Estimation of the total surface area in Indian elephants (Elephas maximus indicus)

Twenty-four adult Indian elephants (Elephas maximus indicus) of both sexes and different ages and weights, belonging to the Temple Devaswoms, the Forest Department of the Government of Kerala and the Gemini Circus formed the experimental subjects from which formulae were derived to predict the total surface area from either body measurements or areas of individual regions. Several models, using the parameters studied either singly or in combination, were tried independently for males and females and also for adults irrespective of sex. The best prediction of total surface area (S) in m² was obtained for adults irrespective of sex by using the two parameters, the height at the shoulders (H) in m and forefoot pad circumference (FFC) in m in the formula S=–8.245+6.807H+7.073FFC. No significant improvement in the accuracy of prediction resulted from the use of the independent best fit formulae for males and females. The conventional method of using the exponential of body weight (kg) for predicting suface area was not found to yield an equivalent accuracy in these animals.     

江苏省蚕桑综合利用模式分析

本文阐述了蚕桑综合利用是提高蚕桑产业经济效益的重要途径之一.江苏省是蚕桑生产大省,桑、蚕及其附属物和衍生物资源丰富,综合利用的潜能很大.文章结合江苏省蚕桑综合利用实际,分析蚕桑综合利用几种发展模式及经济效益.分析了当前江苏省蚕桑综合利用存在的主要问题,提出了蚕桑综合利用发展建议.     

Audiograms estimated from brainstem tone-evoked potentials in dogs from 10 days to 1.5 months of age

The objective of this study was to build audiograms from thresholds of brainstem tone-evoked potentials in dogs and to evaluate age-related change of the audiogram in puppies. Results were obtained from 9 Beagle puppies 10-47 days of age. Vertex to mastoid brainstem auditory-evoked potentials in response to 5.1-millisecond Hanning-gated sine waves with frequencies octave-spaced from 0.5 to 32 kHz were recorded. Three dogs were examined at 10, 13, 19, 25, and 45 days. Four other dogs were examined at 16 days. Data from 7 dogs between 42 and 47 days of age were pooled to obtain audiogram reference values in 1.5-month-old puppies. The best auditory threshold lowered from above 60 dB sound pressure level (SPL) to values close to 0 dB SPL between 13 and 25 days of age and then stabilized. The audible frequency range widened, including 32 kHz in all tested dogs from the 19th day. In the 7 1.5-month-old puppies, the mean auditory threshold decreased by 11 dB per octave from 0.5 to 2 kHz. The auditory threshold was lowest and held the same value from 2 to 8 kHz. The mean auditory threshold increased by 20 dB per octave from 8 to 32 kHz. Near threshold, click-evoked potentials test only a small part of the audible frequency range in dogs. Use of tone-evoked potentials may become a powerful tool in investigating dogs with possible partial hearing loss, including during the auditory system maturation period.     

银翘天甘含药血清制备工艺的优化

本研究通过单因素试验和响应面分析设计优化银翘天甘醇提物制剂含药血清的制备工艺,研究采血时间、给药次数及给药浓度对小鼠血清中绿原酸含量的影响。结果表明,银翘天甘醇提物制剂含药血清最佳制备工艺条件为:给药浓度为0.024 g/mL,给药4次,于最后一次给药后33 min采血。此条件下含药血清中绿原酸含量达到33.34μg/mL。     

PET/CT today and tomorrow in veterinary cancer diagnosis and monitoring: fundamentals,early results and future perspectives

Functional imaging using positron emission tomography (PET) plays an important role in the diagnosis, staging, image‐guided treatment planning and monitoring of malignant diseases. PET imaging complements conventional anatomical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI). The strength of CT scanning lies in its high spatial resolution, allowing for anatomical characterization of disease. PET imaging, however, moves beyond anatomy and characterizes tissue based on functions such as metabolic rate. Combined PET/CT scanners were introduced commercially in 2001 and a number of technological advancements have since occurred. Radiolabelled tracers such as ¹⁸F‐fluorodeoxyglucose (FDG) and ¹⁸F‐fluorothymidine (FLT) allow visualization of various metabolic processes within cancer cells. Many studies in human oncology evaluating the utility of PET/CT have demonstrated clinical benefits. Few veterinary studies have been performed, but initial studies show promise for improved detection of malignancy, more thorough staging of canine cancer and determination of early response and disease recrudescence.