Pleistocene extinction of genyornis newtoni: human impact on australian megafauna

More than 85 percent of Australian terrestrial genera with a body mass exceeding 44 kilograms became extinct in the Late Pleistocene. Although most were marsupials, the list includes the large, flightless mihirung Genyornis newtoni. More than 700 dates onGenyornis eggshells from three different climate regions document the continuous presence of Genyornis from more than 100,000 years ago until their sudden disappearance 50,000 years ago, about the same time that humans arrived in Australia. Simultaneous extinction of Genyornis at all sites during an interval of modest climate change implies that human impact, not climate, was responsible.     

Monensin toxicosis in water buffaloes (Bubalus bubalis).

The consumption of monensin-containing feed resulted in deaths of water buffaloes from a feedlot in which cattle and buffaloes were kept together. The monensin formulation was recommended only for use in cattle. Anorexia, muscular weakness, dyspnea, and recumbency were the major clinical findings. The most significant gross lesions were focal pale areas in semitendinosus and semimembranosus muscles, in which segmental necrosis of myofibers was seen microscopically. To compare susceptibilities of species to monensin, 3 bovine calves and 3 buffalo calves were orally dosed. At 5, 7.5, and 10 mg/kg of monensin, only the buffaloes became ill and died. Clinical signs initiated 18-20 h postdosing and were comparable to those from field cases. Gross changes consisted of ascites, hydrothorax, hydropericardium, hepatomegaly, and focal pale areas in the myocardium and to a lesser degree in semitendinosus and semimembranosus muscles. Histopathological changes also resembled those from the field cases, but were especially pronounced in the myocardial cells. The hypothesis that buffaloes could have a lower tolerance to monensin than cattle has been supported by experimental cases.     

内蒙古典型草原羊草生长高度研究

通过对内蒙古典型草原羊草的试验研究,得出羊草的旬生长高度与旬平均气温、旬降水量和土壤含水量相关密切,5～8月牧草每旬的生长高度与前一旬生长高度相关系数达0.964,羊草的生长符合线性生长规律。由于羊草在生长后期受到自身生长节律的影响,符合Logistic生长曲线的特征。在研究中建立了多元线性回归模型和Logistic生长曲线模型,并建立了生长高度预测模型。经拟合检验效果较好,预测模型能在一定精度水平上准确地预测羊草的生长高度。     

Serum biochemical profile,enzymatic activity and lipid peroxidation in organs of laying hens fed diets containing cashew nut shell liquid

The objective of this study was to evaluate the effect of feeding laying hens diets containing cashew nut shell liquid (CNSL) as a source of anacardic acid on the blood biochemical parameters as well as the enzymatic activity and lipid peroxidation of liver and tissues of the reproductive system (ovary, magnum, and uterus). A total of 216 Hisex White commercial laying hens were distributed randomly into six treatments, with six replicates of six birds. Treatments consisted of a diet without growth promoter (GP); a diet with GP; and diets without GP, with addition of increasing levels of CNSL (0.25, 0.50, 0.75 and 1.0%). Addition of CNSL to the diet did not affect the blood biochemical parameters (uric acid, creatinine, alanine aminotransferase, aspartate aminotransferase, total cholesterol, high density lipoproteins, low‐density lipoproteins and triglycerides), the enzymatic activity (superoxide dismutase and nonprotein sulphydryl groups) in the organs (liver, ovary, magnum and uterus) or the peroxidation of lipids from the blood serum, liver, magnum and uterus (p > 0.05). However, the addition of 0.75% and 1.00% CNSL provided a lower thiobarbituric acid reactive substances content in the birds' ovary (p < 0.001) compared to birds of other treatments, whereas the treatment without the GP provided a higher value. Addition of up to 1% of the CNSL as a source of anacardic acid in the laying hens' diets does not influence blood biochemical parameters or the endogenous enzymatic activity in the liver, ovary, magnum and uterus, but affects the lipid peroxidation in the ovary, although the problem is reduced from the inclusion of 0.75% CNSL.     

野罂粟种芽低温发育及叶片冰点的研究

通过对野罂粟种芽低温发育情况、叶片冰点及单株野罂粟受冻害后活力恢复情况的研究,了解到其种芽可以在3.0~5.0℃低温范围内进行根、茎、叶分化生长。单株野罂粟芯部嫩叶和外部老叶的冰点不同,芯部叶片冰点为-6.0℃,外部叶片冰点为-5.0℃。历经一夜低温冻害后,外部老叶受冻枯萎,不能恢复活力,而芯部叶片仍能恢复生长。     

离子束介导转基因技术的研究及应用进展

对离子束介导转基因技术的原理及优点、转基因方法、在农作物育种上的应用、研究现状、存在的问题等方面进行了评述，并对离子束介导转基因技术的应用前景进行了展望。     

农业生产计划模拟退火算法应用

针对有些企业生产计划编制问题，提出了基于模拟退火算法(SA)的生产计划算法，并给出了生产计划算法的描述，依据实验数据分析了生产计划算法的性能。     

需求开发的知识转移模型研究

本文首先论述了知识转移和需求工程的主要内容,并对需求开发主体的知识势能及特点进行界定,得出需求工程的成功取决于需求开发双方良好的知识转移,最后文章提出适用于需求开发的知识转移模型。