Exploring the limitations of pathophysiological indicators used for targeted selective treatment in sheep experimentally infected with Haemonchus contortus

Identifying which sheep to treat as part of a Targeted Selective Treatment approach to gastro-intestinal nematode control relies entirely on the efficacy of the indicators. Indicators such as FAMACHA© (anaemia), DISCO (diarrhea) and reductions in weight gains were designed specifically to reflect those sheep experiencing symptomatic consequences of infection. Using the gastro-intestinal nematode Haemonchus contortus as a model species, this study explored the utility and sensitivity of these indicators under controlled experimental conditions on 63 adult sheep. The potential effect of sheep with different H. contortus resistance phenotypes on indicator efficacy was compared in three different phenotypes, i.e. high (Blackbelly females), medium (Blackbelly rams) and low resistance (Romane rams). The potential effect of the H. contortus isolate on indicator efficacy was also explored by using four different isolates, with varying anthelmintic resistance capacities, to infect the sheep. We limited the study to the first month of infection to evaluate the interest of these indicators as an early predictive means for controlling infection. The pathophysiological indicators FAMACHA© and DISCO do not reflect infection intensity based on Faecal Egg Counts, nor do reductions in weight gains. FAMACHA© was however a good indicator of anaemia with strong correlations to haematocrit. There was little agreement among the three indicators to identify the same animals in need of treatment and even combining them did not increase their predictive value of infection intensity or relative host damage from infection. The indicator sensitivity was influenced by the H. contortus isolate and sheep resistance phenotype in which they were tested. One isolate was poorly infective but induced high levels of anaemia (FAMACHA©) and diarrhea (DISCO) compared to the three others. The FAMACHA© and DISCO had higher values in the sheep group with a medium resistance phenotype (Blackbelly rams) indicating higher levels of damage compared to the high and low resistance phenotypes. We conclude that there is no ‘one size fits all’ approach to the use of indicators for Targeted Selective Treatment and the indicators should be calibrated to farm-specific conditions to increase their efficacy.     

广丰马家柚成熟前期品质与环境因子研究＋增刊

马家柚是我国柑橘地方良种,但品质易受环境影响。为进一步明确气象因子对马家柚品质的影响,本研究测定并分析了2013-2023年的气象数据和马家柚品质数据,为下一步通过栽培措施或者设施条件等技术提升马家柚品质提供依据。结果表明：①8月至11月中旬的气象条件对马家柚影响最大,其9月是最关键月份。②有效积温高,日较差大,日照时数多,有利于提升马家柚品质,而降水量多会显著降低马家柚品质。③根据综合评比,正常管理条件下,有利于马家柚达到可溶性固形物为10 %以上的气象指标：8月-11月中旬的有效积温1545.9 ℃以上,日较差9.5 ℃以上,日照时数616.3 h以上,降水量163.1mm以下。④关键月份9月的气象指标为有效积温481.1℃以上,日较差8.9 ℃以上,日照时数累计180.5 h以上,降水量小于97.6 mm以下。     

西藏拉孜县草地植物群落的TWINSPAN分类及其物种多样性研究

应用双向指示种(TWINSPAN)分类技术对西藏拉孜县草地植物群落的71个样方进行分类和生物多样性研究;根据丰富度、均匀度和多样性指数,对分类后得到的群落类型进行排序,并探讨环境因子和草地植物群落多样性指标之间的关系。TWINSPAN分类的结果表明,上述草地植物群落可以划分为22个群落类型。通过海拔高度、经度、纬度、坡向和坡度与3个多样性指标的相关分析,只有海拔高度与均匀度之同星显著的负相关关系,即随着海拔的升高均匀度降低,而其它的环境因子与多样性指标之间无显著相关关系存在。     

区域土地资源可持续利用评价指标体系的研究

从土地利用系统的角度,分析土地资源可持续利用的标准.构建了区域土地资源可持续利用指标体系的基本框架,其指标体系包括目标层、准则层、分目标层、指标层4个层次,并对各指标层进行说明。     

Carabid beetle (Coleoptera: Carabidae) diversity in the black spruce succession of eastern Canada

This study provides the first assessment of carabid beetle diversity in a natural forest context that encompasses a complete black spruce (Picea mariana) natural succession. Boreal forest conservation has been based on several assumptions about forest age that only consider species richness without accounting for species composition. It has also been guided by studies of incomplete chronologies that do not include naturally burned or old-growth stages. Twenty-one forest stands of different ages following fire - from recently burned to old-growth stages (0-340 years of age) - were sampled, revealing a strong relationship between age of forest and diversity of Carabidae. Over time, species richness followed a parabolic U-shaped pattern both with observed (Obs) and predicted richness (ACE). Chronological clustering identified four groups of species in the succession: the ‘burned’ group characterized 0-2-year-old forests, ‘regenerating’ (21-58 year), ‘mature’ (70-170 year) and ‘old-growth’ (177-340 year). The time spans corresponding to each of these assemblages lengthen with age of forest at an exponential rate. Ward’s and K-means (clustering without constraint) provided support for the four assemblages but showed variation between individual successions, particularly for the ‘regenerating’ assemblage, identified as the most heterogeneous. The IndVal method identified characteristic species in every stage of the succession, particularly Sericoda spp. in the burned stage and Dromius piceus and Platynus mannerheimii associated with old-growth stands. The results obtained here show that diversity of Carabidae varies in primeval conditions according to age of forest and such variation should be taken into account when conservation issues are involved.     

绥中干旱分析

利用绥中县1956-2012年气象资料,采用统计分析方法,对近57年绥中的干旱状况进行分析,并对此提出了相应的防御对策。结果表明,在57年中,绥中共发生春旱27年,严重春旱15年;共发生伏旱30年,严重伏旱21年;共发生秋吊19年,严重秋吊12年;共发生春夏连旱14年,伏秋连旱13年,春旱、伏旱和秋吊同时出现的三季连旱8年。     

我国农村贫困测度动态指标体系的构建

从我国农村贫困的实际出发,利用福利经济学的相关理论,在分析国际上衡量贫困的主要指标的基础上,通过引入"动态贫困差异率",构建起一套测度我国农村贫困状况的动态指标体系。     

农业综合开发项目绩效评价指标体系研究

为了客观衡量农业综合开发的实际业绩和效率,设定定量与定性指标,构建了农业综合开发绩效评价指标体系,并将绩效评价指标体系应用到2009-2012年农业综合开发3年总验收工作中,以进一步验证指标标准的合理性和数据资料的评价的准确性,科学地指导验收工作。     

毛乌素沙地与植被有关的地下水环境研究

[目的]研究毛乌素沙地与植被有关的地下水环境。[方法]选择毛乌素沙漠腹地,研究沙漠地区植被与地下水的关系,建立了沙漠地区的研究植被与地下水关系的指标体系,即植被的种群、地下水埋深、包气带含水率、地下水矿化度和包气带含盐量等,以及相应的野外工作方法。[结果]结果表明,研究区分布有9个主要的植被种群,沙蒿（Artemisia）、沙柳（Salixpsammophila）和苔草（Carex）是优势植被;地下水矿化度在沙丘地区为100～300mg/L,滩地为800mg/L左右;包气带含水率全年维持在8%～16%;沙丘含盐量小于0.2%,滩地含盐量大于0.3%。[结论]这些成果为研究该区植被与地下水的关系提供了依据。     

葫芦岛市春旱监测和春季第一场透雨指标的确定

利用葫芦岛地区1959年到2005年3~5月的逐日气温和降水资料,确立了不同干旱程度下春季第一场透雨指标,并对春季干旱进行了分析。