母牛胎衣不下因素的调查

母牛分娩12小时后胎膜仍滞留可视为病态,叫胎衣不下,往往因此引起生殖器官的疾病,甚至发生微生物感染继发败血症,对养牛业影响极大。笔者整理了1993年至1994年中48头胎衣不下母牛的临床资料,就季节、胎次、营养、子宫疾病以及运动等问题找到一定关系。 季节关系 临床上发现,母牛胎衣不下,有明显的季节性,以冬春季节发病率高,占总数的80％,其原因与冬春姑饲期,缺乏必要维生素、矿物质、尤其用棉籽多影响VA的吸收有关,此外冬春农闲,母牛运动少、不放牧也是一个重要因素。

牛群卸任与谢军落选

尽管存在程序上的瑕疵,四年前牛群仍然顺利当选为蒙城副县长,掀起了轰轰烈烈的"造牛运动";四年后,尽管已有北京棋院院长的资历和国际棋界的影响力,谢军却因为笔试成绩未进前五名,未获面试资格,无缘北京市体育局副局长的职位。牛群是娱乐界的大腕,谢军是棋界的明星,这两位在社会公共生活中的名气和各自领域的影响力可谓旗鼓相当。然而牛群当年顺利任职,谢军本次无奈落选。

头号女斗牛士败在“男牛”手下

西班牙最著名的女斗牛土斯蒂娜·桑切斯要退役了!她告别斗牛场的原因不是庞大的斗牛过于凶猛,而是这一职业中的大男子主义难以抵御。 桑切斯一年前成为马德里最富盛名的拉斯文塔斯斗牛场唯一女斗牛士,已俨然确立世界一流斗牛士的地位。然而,据桑切斯的父亲和经纪人介绍。

早春如何养护耕牛

俗话说:“冬冷不算冷,春冷冻死牛。”由于耕牛经过一个冬季的关栏饲养,再加上长期饲喂稻草,营养不足,牛体消瘦,抗寒能力减弱,遇上“早春寒”,则极有可能被冻死。那么如何在“早春寒”的情况下避免耕牛死亡呢?

Boundary layer flow of third grade nanofluid with Newtonian heating and viscous dissipation

Two-dimensional boundary layer flow of an incompressible third grade nanofluid over a stretching surface is investigated.Influence of thermophoresis and Brownian motion is considered in the presence of Newtonian heating and viscous dissipation.Governing nonlinear problems of velocity, temperature and nanoparticle concentration are solved via homotopic procedure.Convergence is examined graphically and numerically. Results of temperature and nanoparticle concentration are plotted and discussed for various values of material parameters, Prandtl number, Lewis number, Newtonian heating parameter, Eckert number and thermophoresis and Brownian motion parameters. Numerical computations are performed. The results show that the change in temperature and nanoparticle concentration distribution functions is similar when we use higher values of material parameters β1 andβ2. It is seen that the temperature and thermal boundary layer thickness are increasing functions of Newtonian heating parameter γ.An increase in thermophoresis and Brownian motion parameters tends to an enhancement in the temperature.

Existence and Uniqueness of Nested Regular Quadrilateral Central Configurations

Two cases of the nested configurations in R3 consisting of two regular quadrilaterals are discussed. One case of them do not form central configuration, the other case can be central configuration. In the second case the existence and uniqueness of the central configuration are studied. If the configuration is a central configuration, then all masses of outside layer are equivalent, similar to the masses of inside layer. At the same time the following relation between r(the ratio of the sizes) and mass ratio b = m/m must be satisfied in which the masses at outside layer are not less than the masses at inside layer, and the solution of this kind of central configuration is unique for the given ratio (6) of masses.

Classical Mechanics and Quantum Mechanics

The Newton equation of motion is derived from quantum mechanics.

Thermodynamic Equilibrium

The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accounts for all factors that determine it for all types of equilibrium. Standard definitions of thermodynamic equilibrium are incomplete. They do not take account of all factors that determine such equilibriums, discuss the impediments which may prevent them being reached or relate the properties that define equilibriums to the physical reasons that determine them when impediments are present. The laws of thermodynamics determine the requirements for equilibrium. These laws arise from the physical behaviour of the molecules in molecular systems and are consequences of the conservation of energy, the energies of molecules, statistics, Newton＇s laws of motion, and the equi-partition of energy. The standard definition of thermodynamic equilibrium correctly defines equilibrium whenever impediments are not factors. The discussion demonstrates how impediments arise, accounts for their role in defining equilibrium and how they relate to the energies of molecules at the conditions of the system. The new definition applies to all types of equilibrium.

Identification of Sperm Subpopulations in Water Buffalo Ejaculates： Changes in Cryopreservation Stages and Bull Variation

This study aimed to identify and characterize the sperm subpopulations existing in water buffalo semen using a computer assisted sperm analyzer （CASA）, as well as assess the effects of cryopreservation on the sperm subpopulation structure and evaluate bull variability. The semen of eight Bulgarian Murrah bulls was collected by four times in an interval of one week each. The semen was cryopreserved following a standard protocol and sperm kinematics was assessed. Clustering methods were applied to individual sperms, forming two significantly different （P 〈 0.05） subpopulations （P1 and P2）. Subpopulation P1 represents those spermatozoa that moved most rapidly and progressively （46.29%）, and subpopulation P2 includes spermatozoa with relatively low velocity or poorly motile but with high progressiveness （53.41%）. There was a decline on the population of P1 sperms from fresh （52.52%）, pre-freeze （45.73%） to post-thaw （35.17%） stages and significant difference on the sperm kinematics between P1 and P2. A significant decline in the values of distance, velocity and amplitude of lateral head （ALH） parameters were observed at post-thaw stage, while an increase was observed on trajectory and beat cross frequency （BCF） kinematics. Values of sperm kinematics were also significantly different （P 〈 0.05） among all bulls. The frequency distribution of spermatozoa on both subpopulations P1 and P2 was quite similar for all bulls in pre-freeze and post-thaw stages, but with significant （P 〈 0.05） variability on fresh stage. Bulls with the highest maintained frequency of P1 sperms are denoted as good freezer bulls. In sum, kinematic characterization of water buffalo sperm and clustering into subpopulation enable to identify bulls that are more resistant to cryopreservation and production of quality semen for genetic propagation.

Light Propagation in the Second post-Newtonian Approximation of Scalar-Tensor Theory of Gravity

In this paper, we use the metric coefficients and the equation of motion obtained in the second post- Newtonian approximation of scalar-tensor theory to derive the second-order light propagation equation and the light deflection angle and compare it with previous works. These results are useful for precision astrometry missions like ASTROD, GALA, Darwin and SIM which aim at astrometry with micro-arcsecond and nano-aresecond accuracies, and need for the second post-Newtonian framework and ephemeris for observations to determine the stellar and spacecraft positions.

Digital Ecologies as Tractarian Systems

This paper explores Wittgenstein＇s early work as it relates to emerging philosophical problems in ecological modeling. Here I use his thought to structure a logical framework from which to discuss ecological simulation models in a way that captures how these dynamic representations describe a world from which we can draw logical inferences about real-world ecological processes. I argue that Wittgenstein＇s Tractatus Logico-Philosophicus provides a way of reading problems that arise in using simulation as a way to make inferences about the world. Conversely, ecological simulation provides an illustration of a Tractarian system, because the digital world it creates completely describes and is defined by the programing language. This reading is a novel, but productive, way that notes that the language used in modeling requires a hermeneutical approach to make inferences about modeling/real-world relationships.

Effect of Transport Time and Handling on Physiological Responses of Cattle

The objective of this work was to determine the effect of transport time （up to 11 hours） on animal welfare. 540 animals （cows, bulls and calves）, three transport times of 2, 4 to 6, and 10 to 11 hours, and two space allowances （2 m2 and 1.5 m2 per animal for cows and bulls; and 1.2 m2 and 0.8 m2 per animal for calves） were used for the experiment during transport from farms to the abattoir in Uppsala, Sweden. Measurements were made on five animals on each trip. Stress response parameters considered were cortisol, glucose, lactate, creatine kinase and heart rate. Blood samples were taken before and after transport. Heart rate sensors were mounted on the animals at least 30 minutes before loading and measurements were made continuously from farms to the abattoirs until stunning. The results of heart rate measurement indicated that loading, un-loading and forced movement in the stunning box were the most stressful events. However, the results of statistical analysis confirmed that transport time doesn＇t have significant effect （P 〈 0.05） on heart rate. Concentration level of cortisol increased by 10 folds during short transport. However, cortisol concentration decreased with an increase of transport times （P 〈 0.01）. Glucose concentrations increased with transport time in all animal categories （P ≤ 0.01）. Transport time has significant effect on concentration levels of glucose （P ≤ 0.01）, creatine kinase （P 〈 0.001） and lactate （P 〈 0.01） particularly after 6 hours journey time.

The Bovine Tuberculosis Campaign in Mexico： Present and Perspectives

Mexico is considered by different international organizations as a country where the bovine tuberculosis is an endemic problem. However, there are important and consistent improvements in eradicating the disease by the implementation of government policies and with the livestock organization support. The current situation of the program shows good results regarding decreasing the prevalence, and as a consequence, the risk of this disease for public health and animal health, as well as the improvement in animal production and international and national trade. Today, the bovine tuberculosis distribution is almost known in Mexico. In addition, a series of controls and indicators have been established, which allow maintain consistency and reliability in the data that are managed and analyzed.

On the correction of the boundary deficiency in SPH for the frictional contact simulation

Smoothed particle hydrodynamics(SPH)is a mesh-free method which is powerful for large deformation computation of soils.However,the algorithm for the simulation of frictional contact which is common in geotechnical engineering is still quite immature due to the boundary deficiency.In this study,the cause of boundary deficiency in the SPH simulation for frictional contact is analysed.Then,based on mathematical derivation,the method to correct boundary deficiency related to frictional contact is discussed theoretically,where the frictional contact algorithm is established by dividing the computational domain into several subdomains according to the existing contact boundaries and by using contact forces as bridges of these subdomains to fulfil problem solving,and the value of correction coefficient is obtained by comparing the SPH outcome of the contact particles with that calculated through Newton’s second law of motion.At the same time,from the perspective of numerical computation,an optimized value for the correction coefficient is proposed,and a thorough investigation is performed on the cubic spline kernel function and quintic spline kernel function,whose correction coefficients are found to be 2.0 and[2.0,2.16],respectively.Finally,numerical tests are carried out to verify the proposed method.The outcome of the study is helpful to providing theoretical support for the research of frictional contact simulation within the framework of SPH.

Physiological Flow of Jeffrey Six Constant Fluid Model due to Ciliary Motion

The main purpose of this article is to present a mathematical model of ciliary motion in an annulus. In this analysis, the peristaltic motion of non-Newtonian Jeffrey six constant fluid is observed in an annulus with ciliated tips in the presence of heat and mass transfer. The effects of viscous dissipation are also considered. The flow equations of non-Newtonian fluid for the two-dimensional tube in cylindrical coordinates are simplified using the low Reynolds number and long wave-length approximations. The main equations for Jeffrey six constant fluid are considered in cylindrical coordinates system. The resulting nonlinear problem is solved using the regular perturbation technique in terms of a variant of small dimensionless parameter α. The results of the solutions for velocity, temperature and concentration field are presented graphically. B_k is Brinkman number, ST is soret number, and SH is the Schmidth number. Outcome for the longitudinal velocity, pressure rise, pressure gradient and stream lines are represented through graphs. In the history, the viscous-dissipation effect is usually represented by the Brinkman number.

Latest advances in discontinuous deformation analysis method

Discontinuous deformation analysis （DDA） method, proposed firstly by Shi [1] in 1988, is a novel numerical approach to simulate the discontinuous deformation behaviors of blocky rock structures. In DDA, the domain of interest is represented as an assemblage of discrete blocks and the joints are treated as interfaces between blocks. The governing equations of DDA are derived from Newton’s Second Law of Motion and the Principle of Minimum Potential Energy.

Experimental Investigation of Dimensionless Velocity and Shearing Stress in Boundary Layer Flow on Continuous Moving Surface in Power Law Fluids

An analysis is carried out to study the steady flow characteristics from a continuous flat surface moving in a parallel free stream of non-Newtonian power law fluid. The constitutive equations of the fluid are transformed into dimensionless ones. The velocity field is measured by Particle Image Velocimetry. Experimental results are obtained for the distribution of velocity. The influence of wall velocity ratio parameter on boundary layer flow field is observed in the experiment. Dimensionless velocity distribution and shearing stress distribution are obtained by post-processing experimental results. The effects of various physical parameters like velocity ratio parameter and similarity variable on various momentum transfer characteristics are discussed in detail and shown graphically. It is indicated that dimensionless velocity increases with velocity ratio parameter and similarity variable, and that dimensionless shearing stress decreases with velocity ratio parameter and similarity variable.