Controlling factors of sheet erosion under degraded grasslands in the sloping lands of KwaZulu-Natal, South Africa

The current increase in the global demand for food and fresh water and the associated land use changes or misuses exacerbate water erosion which has become a major threat to the sustainability of the soil and water resources. Soil erosion by rainfall and runoff is a natural and geologic phenomenon, and one of the most important components of the global geochemical cycle.Despite numerous studies on crop lands, there is still a need to quantify soil sheet erosion (an erosion form that uniformly removes fertile upper soil horizons) under grasslands and to assess the factors of the environment that control its spatial variation. For that purpose, fifteen 1 m² micro-plots installed within a 23 ha catchment under pasture in the sloping lands of KwaZulu-Natal (South Africa) were monitored during the 2007-2008 rainy season to evaluate runoff (R) and sediment losses (SL). Soil losses computed from the 37 rainfall events with soil erosion averaged 6.45 ton ha⁻¹ year⁻¹with values from 3 to 13 ton ha⁻¹ year⁻¹. SL were significantly correlated with the proportion of soil surface coverage by the vegetation (P < 0.01) whereas the slope gradient, and soil characteristics such as bulk density or clay content were not correlated. R and SL increased as the proportion of soil surface coverage decreased and this trend was used to predict the spatial variations of sheet erosion over the 23 ha catchment. Greater sheet erosion occurred at the catchment plateau and at the vicinity of gully head cuts probably in relation to regressive erosion. Mitigating sheet erosion would require an appropriate management of the soil cover through appropriate management of cattle grazing, especially at places where “natural” erosion is likely to occur.     

斜拉索-粘性阻尼器系统动力特性分析的模态坐标法

粘性阻尼器是抑制斜拉桥拉索振动的一种有效方式.设计拉索减振系统的一个关键步骤是确定斜拉桥-粘性阻尼器系统的等效阻尼比,因此提出了一种分析这一问题的模态坐标法.通过准确地选取第一振型的振型函数,只需50阶振型就可得到满意的效果.以一根实桥拉索的设计参数为例,应用本方法考察了各种因素对模态阻尼比的影响.     

Thymoquinone enhances the activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic rats

The aim of this study was to examine the effect of glycemic control using thymoquinone (TQ) on energy metabolism related enzymes in leukocytes of streptozotocin (STZ)-induced diabetic rats. The treatment of both TQ and insulin commenced 4 weeks after induction of diabetes. Plasma glucose, cholesterol and triglycerides levels were significantly reduced after TQ treatment, whereas immunoreactive insulin (IRI) showed significant increase. The activities of malate dehydrogenase (MDH) in cytosolic and mitochondrial fractions of peripheral blood leukocytes were significantly higher in rats treated with TQ and insulin as compared to that in diabetic controls. On the other hand the activities of lactic dehydrogenase (LDH) showed no significant changes between groups. ML ratio (cytosolic MDH/LDH specific activity ratio) was restored to those in the control rats. The results of this study demonstrate that TQ significantly increased insulin level and the activities of cytosolic and mitochondrial MDH in leukocytes of STZ-diabetic rats.     

关于天方茶叶集团绿色农产品的一体化经营研究

在分析安徽天方茶叶集团绿色农产品一体化经营中的成功经验与存在不足的基础上,提出了选择合适的组织形式,真正发挥合约效力;协调好企业与农户之间的利益关系;重视产品品牌和企业形象的整体战略实施;重视科技的进步和推广;加强与政府部门沟通,充分发挥政府部门的协调作用等完善天方茶叶集团绿色农产品一体化经营的对策与建议,以供相关企业借鉴。     

如何实现预算管理的实效

全面预算管理是现代化企业管理的一种重要手段，也是一种使企业的资源获得最佳生产率的管理模式，在企业规划、协调、控制、考评、激励等活动中有显著的作用。本文从形成良好的预算管理系统、建立健全预算管理网络、建立灵敏的财务反应机制、完善预算控制、创造推行全面预算管理的环境5个方面，对实施预算管理进行了论述，以期树立正确的预算观念，真正实现预算管理的实效。     

四轮驱动汽车牵引力模糊控制方法仿真研究

建立了四轮驱动汽车加速过程的数学模型,采用模糊控制方法,建立了以滑转率为控制对象的汽车牵引力控制系统TCS(Traction Control System),用Matlab的模糊工具箱进行了模糊控制器的设计,并在Simulink仿真环境下进行了动态仿真,结果表明:基于模糊控制的TCS可将驱动轮滑转率控制在最佳值附近,有效地改善车辆的牵引性和动力性,抑制驱动轮过度滑转。     

米象金小蜂生物学特性及其对玉米象种群控制作用研究

本项研究明确了玉米象的寄生性天敌米象金小蜂Ｌａｒｉｏｐｈａｇｕｓｄｉｓｔｉｎｇｕｅｎｓｉｓ（Ｆｅｒｓｔｅｒ）在山东省泰安地区室内变温条件下,一年发生５代,以老熟幼虫在寄主体内越冬。在２６～３２℃、相对湿度７８％～８５％时,完成一代平均１７．６ｄ。当每公斤虫粮有玉米象幼虫６００头左右时,分别接雌雄成蜂１０和２０对以上,２个月后的控害效果依次为７１．６３％和９０％以上。由此,提出了益害比为１∶３０的该峰保护利用指标。根据连续两代蜂不同密度（ｘ１与ｘ２）分别对玉米象控制后的残虫数量（ｙ１与ｙ２）,组建了相关回归式：Ｙ１＝９８．４８２９－２．９１７７ｘ１;Ｙ２＝４４７．８１３６－８．２４０５ｘ２。为预测不同蜂量的控害作用提供了科学依据。     

How widespread is Parthenium hysterophorus and its biological control agent Zygogramma bicolorata in South Asia?

Parthenium hysterophorus is a weed of global significance causing severe economic, environmental, human and animal health problems in Asia, Africa, Australia and the Pacific. In South Asia, P. hysterophorus occurs in India, Pakistan, Sri Lanka, Bangladesh and Nepal. A host-specific leaf-feeding beetle Zygogramma bicolorata from México was introduced into India in 1984, as a biological control agent for P. hysterophorus . In this study, a GIS-based distribution map of P. hysterophorus and its biological control agent Z. bicolorata in South Asia based on meta-analysis is presented. The map highlights the limited published information on P. hysterophorus incidence in many of the states and territories in India, as well as in neighbouring Bangladesh, Bhutan, Nepal and Pakistan. Incidence of Z. bicolorata was recorded as three distinct clusters, covering many states in India. In Pakistan, Z. bicolorata was recorded in the Punjab region bordering India. A CLIMEX model based on the current distribution of Z. bicolorata in India suggests that the geographic range of this agent in India and Pakistan can extend to other P. hysterophorus -infested areas in the region. The CLIMEX model also suggests that all of Bangladesh and Sri Lanka, and parts of Nepal are climatically suitable for Z. bicolorata.