Evaluation of three hormonal protocols for anovulatory lactating cows under regulations restricting the use of estrogenic compounds

When European Union regulations restricted the use of estrogenic compounds in food‐producing animals, refined hormonal protocols were no longer applicable for anovulatory cows. However, Ovsynch and its adaptations are routinely and uniformly applied to all cows regardless of ovarian function. To evaluate their efficacy on anovulatory cows, 143, 147 and 144 anovulatory cows received Ovsynch, Presynch and G6G protocols, respectively. In comparison, 150 cyclic cows were bred without using a synchronized protocol. Results showed that cows in the Presynch group had luteolysis responding to the last prostaglandin F_2α (PGF_2α) injection greater than the Ovsynch group. The serous progesterone levels at the first gonadotropin‐releasing hormone of Ovsych and the last PGF_2α injection was greater in the G6G group than the other two hormonal treatment groups. Concentrations of Ca²⁺ and total protein in cervical mucus in all three hormone‐treated groups before artificial insemination (AI) were significantly different from the controls. The G6G group obtained a greater pregnancy rate compared with Ovsynch and Presynch, but significantly less than the controls. For open cows in the Ovsynch group, estrus rate within 24 days after the first AI was significantly less than the controls. In conclusion, the G6G treatment resulted to better reproductive performance in anovulatory cows.     

Rapid brain MRI protocols result in comparable differential diagnoses versus a full brain protocol in most canine and feline cases

Evaluation of brain disease in veterinary patients uses a wide variety of MRI sequences. A shortened protocol that maintains consistency of interpretation would reduce radiologist reporting time, patient anesthetic time, and client cost. The aims of this retrospective, methods comparison, observer agreement study were to evaluate whether abbreviated MRI protocols alter differential diagnoses and recommendations compared to our institution's standard protocol; evaluate interobserver agreement on standard brain MRIs; and assess whether differential diagnoses change after postcontrast images. Normal and pathologic canine and feline brain MRIs were retrieved from hospital archives. Three protocols were created from each: a 5-sequence noncontrast enhanced Fast Brain Protocol 1 (FBP1); a 6-sequence contrast-enhanced Fast Brain Protocol 2 (FBP2); and an 11-sequence standard brain protocol (SBP). Three blinded veterinary radiologists interpreted FBP images for 98 cases (1 reader/case) and SBP images for 20 cases (3 readers/case). A fourth observer compared these interpretations to the original MRI reports (OMR). Overall agreement between FBPs and OMR was good (k = 0.75) and comparable to interobserver agreement for multiple reviews of SBP cases. Postcontrast images substantially altered conclusions in 17/97 cases (17.5%), as well as improved interobserver agreement compared to noncontrast studies. The conclusions reached with shortened brain protocols were comparable to those of a full brain study. The findings supported the use of a 6-sequence brain MRI protocol (sagittal T2-weighted [T2w] TSE; transverse T2w turbo spin echo fluid-attenuated inversion recovery, T2*-weighted gradient recalled echo, T1-weighted spin echo, and diffusion weighted imaging/apparent diffusion coefficient; and postcontrast transverse T1-weighted spin echo) for dogs and cats with suspected intracranial disease.     

Preventive effects of CIDR-based protocols on premature ovulation before timed-AI in Ovsynch in cycling beef cows

Ovsynch is a program developed to synchronize ovulation for timed breeding. In this paper, the authors investigate whether controlled internal drug release (CIDR)-based protocols prevent premature ovulation before timed-artificial insemination (AI) when Ovsynch is started a few days before luteolysis in cycling beef cows. Nine beef cows at 16 days after oestrus were treated with (1) Ovsynch, i.e. gonadotropin releasing hormone (GnRH) analogue on day 0, prostaglandin (PG) F(2alpha) analogue on day 7 and GnRH analogue on day 9 with timed-AI on day 10, (n=3); (2) Ovsynch+CIDR (Ovsynch protocol plus a CIDR for 7 days from day 0, n=3), or (3) oestradiol benzoate (OB)+CIDR+GnRH (OB on day 0 in lieu of the first GnRH treatment, followed by the Ovsynch+CIDR protocol, n=3). In the Ovsynch group (1) plasma progesterone concentrations fell below 0.5 ng/mL earlier (day 5) than in both CIDR-treated groups (2) and (3), where this occurred on day 8. Plasma oestradiol-17beta concentrations peaked on day 8 in the Ovsynch group and on day 9 in both CIDR-treated groups. The dominant follicle ovulated on day 10 in the Ovsynch group and on day 11 in both CIDR-treated groups. Thus, both CIDR-based protocols prevented premature ovulation before timed-AI in Ovsynch when the protocol was started a few days before luteolysis. This reflects the fact that progesterone levels remained high until the beef cattle were treated with PGF(2alpha).     

改进的Dijkstra算法及其在网络中的应用

提高计算机网络网络传输速度的关键是找到最佳的路由实现算法,本文从节约存储空间和提高运算效率方面对传统Dijkstra算法进行了改进,通过分析与比较,这种改进算法的效率优于传统的Dijkstra算法,特别适用于大规模网络。     

适于双向电泳分析的水稻纹枯病菌菌体蛋白提取方法的比较

为建立水稻纹枯病菌菌体蛋白的双向电泳技术,获得分辨度高、重复性好的双向电泳图谱.采用了酚抽提法、TCA/丙酮沉淀法和丙酮沉淀法进行水稻纹枯病菌菌体蛋白质的提取,利用17cm、pH 5 ～8的IPG胶条对样品进行双向电泳,用PDQuest 8.0软件对电泳图谱进行分析,确定电泳的最佳参数.结果显示:采用17cm、pH 5 ～8的IPG胶条能得到较好的双向电泳图谱;同一样品的三种不同蛋白提取方法(酚抽提法、TCA/丙酮沉淀法和丙酮沉淀法)分别得到1278、885、827个蛋白质点.酚抽提法能有效去除样品中的盐分和小分子的干扰,得到背景清晰的蛋白图谱;TCA/丙酮沉淀法和丙酮沉淀法所得图谱有一定的杂质干扰,同时TCA/丙酮沉淀法和丙酮沉淀法有蛋白点缺失,尤其在碱性端存在明显缺失现泉.研究结果建立了一套适于水稻纹枯病菌菌体蛋白的可靠提取方法和双向电泳体系,为进一步研究其蛋白质组学奠定了基础.     

水声通信网MAC协议的分析与仿真

基于水声通信网的特殊的组网形式,它的MAC层协议的设计目标不同于传统的陆地无线网,节约能量是其首要考虑的问题。在目前现有的MAC协议中,802.11的DCF机制是基于竞争类的代表;而S-MAC协议则综合了固定分配类和随机竞争类的优点并以节能和可扩展性为主要设计目标。本文通过NS仿真对水声通信网应用这两种协议的性能进行了分析比较。     

TCP/IP协议脆弱性分析

TCP/IP协议是网络发展的一个基础，但是该协议确存在着致命的弱点，盲目的使用与该协议相关的服务或应用会给网络安全带来隐患，认识到TCP/IP协议的脆弱性进对我们加强网络管理和采用安全技术手段具有指导性作用。     

线切割与镂铣图形的CNC自动编程及虚拟加工技术研究

以AutoCAD R14为开发平台，综合运用ObjectARX SDK、Visual C^ 6.0及CNC技术，在研究了AutoCAD R14的数据结构、平面图形CNC自动编程及加工过程仿真和虚拟现实算法基础上，开发出一种适用于CNC木工镂铣、CNC线切割和CNC激光平面轨迹加工的、集CAD／CNC APT／虚拟加工功能于一体的集成技术。该技术可直接将二维AutoCAD图形快速自动转换成二维CNC加工程序，并可对所编程序进行虚拟加工实验，以检验加工的正确性和可靠性；解决了实际二维平面图形加工CAD／CAM集成及其一体化的瓶颈问题。     

动态车辆路径问题研究综述

指出了动态车辆路径问题是运筹学和组合优化领域的前沿研究方向,研究动态车辆路径问题具有重要的理论和现实意义。阐述了动态车辆问题（DVRP）,根据动态信息的特征将动态车辆路径问题分为随机车辆路径问题（SVRP）和模糊车辆路径问题（FVRP）。从动态车辆路径问题的建模、算法和仿真优化三个方面分析了其研究成果,对现有研究的不足进行了探讨,提出了动态车辆路径问题的进一步研究方向。