基于叶片面积玉米叶片保绿度开花后衰减特性初步研究

采用Excel工作表Origin7.0统计分析软件对基于绿叶面积玉米叶片保绿度开花后衰减特性进行了初步研究,结果表明:玉米开花后叶片保绿度衰减符合方程y=aeb-cx/(1+eb-cx);不同基因型玉米叶片保绿度衰减启动时间、最大衰减速率和最大衰减速率出现时间等衰减特性差异较大;即使相同基因型在不同环境条件下叶片衰减特性也不尽相同.采用y=aeb-cx/(1+eb-cx)模拟方程能比较全面揭示叶片保绿度的动态变化过程.     

美国大学商业化现象及其启示

商业化已经成为美国大学校园里一个普遍的现象.文章首先引入SWOT分析机制,从内部和外部两方面深入探讨美国大学商业化现象产生的原因.接着对商业化现象的四种主要表现形式,即体育竞赛、产学研合作、推广教育课程以及大学内部课程结构的商业化等进行分析.这些商业化既给大学带来利益,也使大学付出代价.大学应该划出一条适当的界限,既保护大学核心价值,又推动大学更好地为社会发展服务.     

Comparison of Multistix PRO dipsticks with other biochemical assays for determining urine protein (UP), urine creatinine (UC) and UP:UC ratio in dogs and cats

BACKGROUND: Urine protein: urine creatinine (UP:UC) ratio determined from the quantitative measurement of protein and creatinine in a single urine sample is the best feasible assessment of clinically significant proteinuria in dogs and cats. A dipstick that measures urine protein, urine creatinine, and UP:UC ratio has been used in human medicine and could have application for veterinary practice. OBJECTIVE: The objective of this study was to compare the Multistix PRO dipstick (Bayer Corporation, Elkhart, IN, USA) to other biochemical methods for determination of urine protein and creatinine, and UP:UC ratio in canine and feline urine. METHODS: A complete urinalysis, including sulfosalicylic acid (SSA) precipitation, was performed on urine samples submitted to our laboratory between February and April 2003 from 100 dogs and 49 cats. Urine protein and creatinine concentrations were determined by the Multistix PRO dipstick using a Clinitek 50 analyzer (Bayer) and compared with the results of SSA precipitation and quantitative biochemical analysis. The UP:UC ratios from the dipstick results (calculated by the Clinitek 50 and also manually) were compared with those calculated from quantitative values. Pearson product-moment correlation analysis and diagnostic sensitivity and specificity (using quantitative results as the gold standard) were determined. RESULTS: For both canine and feline urine, protein and creatinine concentrations determined by the Multistix PRO correlated closely with quantitative concentrations for protein (dogs r = .78, P = .0001; cats r = .87, P = .0001) and creatinine (dogs r = .78, P = .0001; cats r = .76, P = .0001). The Multistix PRO was more sensitive and less specific than SSA precipitation for diagnosing clinically significant proteinuria. UP:UC ratios obtained by manual calculation of dipstick results correlated best with quantitative UP:UC ratios in dogs, and had higher specificity but lower sensitivity for the diagnosis of proteinuria. In cats, UP:UC ratios determined by the dipstick method did not correlate (r = -.24, P = .0974) with quantitative values. CONCLUSIONS: The Multistix PRO, with manual calculation of UP:UC, may be a good alternative for the diagnosis of clinically significant proteinuria in dogs, but not cats. Dipstick creatinine concentration should be considered as an estimate.     

中国大鲵子二代制种技术的研究

为了推动中国大鲵人工生态繁殖和迁地保护的成功 ,系统介绍了中国大鲵子二代制种的技术路线 ,首先收集野生中国大鲵经人工驯养成为亲本种鲵 ,种鲵进行人工催产获得卵子、精子 ,经人工授精产生受精卵 ,再经人工孵化获得子一代幼苗 ,子一代经人工培育 2～ 3年产生子一代后备种鲵 ,再通过生理生态人工强化培育获得 1998年、1999年子一代亲本 ,然后经人工繁殖产生子二代大鲵 ,子二代大鲵可以放归自然保护区或供科研、观赏、商品鲵等利用。从 1998～ 2 0 0 3年共生产子一代 1 5万余尾 ,2 0 0 2年生产子二代 12 6 0尾 ,2 0 0 3年 4 80 6尾 (2年合计子二代 6 6 0 6尾 ) ,种群数量从最初的 1996年的 10 0尾增加到 2 0 0 3年的 2 31万尾 ,增长2 31倍 ,实践证明 ,此技术路线正确、可行。     

GMOs in animal agriculture: time to consider both costs and benefits in regulatory evaluations

In 2012, genetically engineered (GE) crops were grown by 17.3 million farmers on over 170 million hectares. Over 70% of harvested GE biomass is fed to food producing animals, making them the major consumers of GE crops for the past 15 plus years. Prior to commercialization, GE crops go through an extensive regulatory evaluation. Over one hundred regulatory submissions have shown compositional equivalence, and comparable levels of safety, between GE crops and their conventional counterparts. One component of regulatory compliance is whole GE food/feed animal feeding studies. Both regulatory studies and independent peer-reviewed studies have shown that GE crops can be safely used in animal feed, and rDNA fragments have never been detected in products (e.g. milk, meat, eggs) derived from animals that consumed GE feed. Despite the fact that the scientific weight of evidence from these hundreds of studies have not revealed unique risks associated with GE feed, some groups are calling for more animal feeding studies, including long-term rodent studies and studies in target livestock species for the approval of GE crops. It is an opportune time to review the results of such studies as have been done to date to evaluate the value of the additional information obtained. Requiring long-term and target animal feeding studies would sharply increase regulatory compliance costs and prolong the regulatory process associated with the commercialization of GE crops. Such costs may impede the development of feed crops with enhanced nutritional characteristics and durability, particularly in the local varieties in small and poor developing countries. More generally it is time for regulatory evaluations to more explicitly consider both the reasonable and unique risks and benefits associated with the use of both GE plants and animals in agricultural systems, and weigh them against those associated with existing systems, and those of regulatory inaction. This would represent a shift away from a GE evaluation process that currently focuses only on risk assessment and identifying ever diminishing marginal hazards, to a regulatory approach that more objectively evaluates and communicates the likely impact of approving a new GE plant or animal on agricultural production systems.     

菜小脉蚜茧蜂发育速率与温度及寄主龄期关系研究

以桃蚜Myzus persicae为寄主,测定了菜小脉蚜茧蜂Diaeretiella rapae在不同温度及不同龄期寄主中的发育速率。算得该蜂的发育起点温度t=8.76±0.13℃,有效温积常数K=139.51±1.60日度。在不同龄期无翅蚜虫中平均发育速率有显著差异,依次为:三龄>四龄>二龄>成蚜>一龄,最快与最慢相差5%。进一步的分析表明,不同龄期对蜂发育适合性的这种差异是由于个体大小不一和内含物营养不同两方面综合导致的     

壮蚕期不同的给桑量对蚕茧产量和质量的影响

本文利用不同的给桑量分别饲养四、五龄蚕,其结果表明:不同的龄期,给桑量对蚕茧的产量和质量的影响是不一致的.四龄期是影响和决定质量的主要时期,五龄是高产的最重要的环节.     

球痢清等药物对人工感染兔肠球虫病的治疗比较试验

４８只３０日龄大耳白杂种兔，试验接种感染兔肠球虫的５种混合孢子化卵囊，将球痢清Ｉ、球痢清Ⅱ、莫能霉素和氯苯胍分别拌在饲料中饲喂，以比较其抗兔肠球虫的效果。通过临床观察，分析克粪便卵囊数的变化，记录增重、计算饲料转化率和对每组扑杀兔作病理组织学检查，结果表明：球痢清抑制卵囊产生、减轻肠道病变、增重及饲料转化率的效果明显，与莫能霉素相近，并显著优于氯苯胍。氯苯胍效果较差，几乎与接种不给药组相同。无显著性差异。因此说明氯苯胍不宜单一继续使用。应引入新的高效抗球虫药，并指导正确使用抗球虫药物。     

Therapeutic Efficacy of Zinc Sulphate Used in Clustered Model Treatment in Alleviating Zinc Deficiency in Cattle and Its Effect on Hormones,Vitamins and Production Parameters

A survey was conducted in 10 districts of northern India. Significant deficiency of zinc was observed in soil, fodders and (cattle) serum samples. The animals showed typical signs of zinc deficiency, namely stiff gait, swelling of hocks and knees, subcutaneous fluid accumulation, rough coat, etc. of variable intensity. A clustered model therapeutic trial was conducted and zinc-deficient cattle were divided into three groups. Group A was provided with mineral mixture containing zinc sulphate. Group B was given mineral mixture without zinc sulphate and group C was given no mineral mixture. Significant improvement (p < 0.01) was observed in the haemoglobin (Hb), total white blood cells (WBC) and total erythrocyte count (TEC) levels at the 7th day of treatment in the animals of group A. Significant improvement in enzyme serum alkaline phosphatase (SAP) was observed in group A animals at the 7th day, while improvement in asparatate aminotransferase (AST), alanine aminotransferase (ALT) and ceruloplasmin (Cp) was observed after 21 days of treatment. Regarding hormones, significant improvement was observed in thyroxine (T₃) and triiodothyronine (T₄), oestrogen and progesterone in group A animals within 14 days of treatment. The values of vitamin A showed a highly significant (p < 0.01) improvement within 7 days of treatment in group A animals and that of vitamin E on the 21 st day of treatment. The milk yield of lactating cattle and body weight of growing calves in group A showed highly significant (p < 0.01) increases at about 14 and 30 days, respectively. It is concluded that zinc sulphate supplementation is highly effective in alleviating zinc deficiency and improving various biochemical and production parameters in cattle. The clustered model treatment provides a better indicator of the most limiting element under field conditions where simultaneous deficiency of various minerals is prevalent.     

基于VB的二维条码识别

对应用最广泛的PDF417二维条码的符号结构及编码原理研究的基础上,建立起一个基于VB的二维条形码识别系统.整个识别算法由图像采集、图像预处理和译码算法三部分组成.实验结果令人满意,为二维条码的识别提供了一条有效的途径.