内蒙古边境地区动物棘球绦虫感染状况调查报告

2008-2010年,在内蒙古自治区选择了6个边境旗(县),借助细粒棘球绦虫粪抗原抗体夹心酶联免疫吸附试验,调查了家(牧)犬棘球绦虫感染率;经屠宰场调查,检查了羊、牛棘球蚴感染水平;通过走访当地疾病防控中心,了解人感染包虫痛的基本情况.连续3年的调查结果显示,犬粪便抗原平均阳性率为13.16%,感染严重地区的犬粪便抗原阳性率最高为16.15%,以牧区的阳性率为最高,且越靠近边境地区感染越严重;羊、牛棘球蚴感染率平均为13.66%,感染严重地区的感染率最高为17.90%,平均感染强度达到了1.36个.调查表明,内蒙古边境地区棘球蚴病依然存在,且严重威胁着人类和家畜的健康,应引起重视.     

紫茎泽兰入侵地土壤微生物对紫茎泽兰和本地植物的反馈

植物与土壤微生物互作及其反馈影响自然界植物群落的竞争性演替。为了明确土壤微生物在我国恶性入侵植物紫茎泽兰传入定殖后迅速竞争性扩张中的作用,通过接种植物根际微生物（紫茎泽兰和本地植物的根际土壤分别进行灭菌处理、添加杀真菌剂处理和无处理（对照））的盆栽法,比较了土壤微生物对紫茎泽兰和2种本地植物（林泽兰和狗尾草）的生长反馈效应。结果显示,根际土壤微生物对3种植物的生长均产生正反馈,紫茎泽兰、林泽兰和狗尾草在添加杀真菌剂处理或灭菌处理的生物量均比对照显著下降。林泽兰和狗尾草的根系AMF侵染率在对照的紫茎泽兰土壤和本地植物土壤中没有显著差异;但在添加杀真菌剂处理后,林泽兰和狗尾草的根系AMF侵染率在紫茎泽兰土壤中比在本地植物土壤中分别高出8102%和897%,说明紫茎泽兰土壤的真菌具有更强的正反馈作用。磷脂脂肪酸（PLFAs）分析土壤微生物群落多样性和功能微生物丰度的结果显示,入侵植物紫茎泽兰土壤和本地植物土壤的土壤微生物群落存在显著差异。综合推断认为,紫茎泽兰入侵后改变了土壤微生物群落结构,从而产生更有利于自身生长的正反馈,进而进一步促进了竞争性扩张。     

Toxicity of the herbicide glufosinate-ammonium to Tetranychus urticae (Acari: Tetranychidae) under laboratory and field conditions

The toxicity of herbicides widely used in apple orchards to the two-spotted spider mite (Tetranychus urticae) was evaluated in laboratory and field studies. In a laboratory study with susceptible T. urticae, glufosinate-ammonium was highly effective against larvae, protonymphs and adults, but non-toxic to eggs. Its efficacy was much greater than that of the commonly used acaricide azocyclotin. The immatures died within 24 h after treatment, suggesting that the nymphicidal action may be attributable to a direct effect rather than an inhibitory action of chitin synthesis. Glufosinate-ammonium showed a positive temperature coefficient of toxicity against T. urticae adults at six temperatures from 10 to 32°C, being more toxic at higher temperatures. Very low levels of resistance to the herbicide were observed in the seven field-collected T. urticae populations resistant to various acaricides. Treatment with glufosinate-ammonium did not cause a repellent response from either adults or immature stages of T. urticae. Paraquat dichloride and glyphosate were ineffective against all stages of T. urticae. In a field study of a population of T. urticae, glufosinate-ammonium when sprayed to weeds caused significant decrease in T. urticae population densities in apple trees for nine weeks after treatment, as compared with the control. Thereafter, a single application of standard acaricides to apple foliage greatly reduced population densities, although there was no difference in the densities between the glufosinate-ammonium-treated and control plots. Based upon laboratory and field data, two single treatments with glufosinate-ammonium to weeds in May and a selective acaricide to apple trees in July may be used to prevent damage by T. urticae. ©1997 SCI     

大模数直齿圆柱齿轮精锻模具的设计

利用积极摩擦一步成形的工艺方案设计大模数直齿圆柱齿轮精锻模具,以工业纯铅为试样进行试验,结果表明:利用积极摩擦作用和新型飞边结构形式能够有效保证直齿圆柱齿轮精锻时齿腔充满,但同时增加了变形力。     

基于改进势场蚁群算法的移动机器人最优路径规划

首先,针对传统人工势场算法存在死锁及局部路径欠优等问题,对其进行改进。利用障碍物检测算法识别出有效障碍物和有效路径中间点,通过引力场和边界条件规划出起点到中间点的局部路径,将中间点置为新的起点进行反复迭代,直至起点与目标点重合则规划完成。其次,针对蚁群算法容易陷入局部最优以及收敛速度较慢等问题,对其进行改进。以改进人工势场算法规划出的路径启发蚁群进行路径搜索,从而避免算法早期由于盲目搜索而导致的路径交叉及收敛速度慢等问题,同时以收敛次数构建负反馈通道,使全局信息素和局部信息素的更新速率跟随收敛次数的变化自适应调节,从而保证了算法全程中收敛速度与全局搜索能力的协调与统一。最后,在Matlab中对本文算法、基本蚁群算法以及文献[23]所述算法分别进行仿真实验。结果表明:在相同的环境模型下,本文算法的收敛速度和搜索能力均优于另两种算法;在给定的简单环境模型下进行路径规划时,本文算法的迭代次数为3次,运行时间为0. 892 s,最优路径长度为28. 627 m;在给定的复杂环境模型下进行路径规划时,本文算法的迭代次数为8次,运行时间为3. 376 s,最优路径长度为31. 556 m,所寻路径对环境的覆盖率为73. 63%。     

Mammary gland tumors in male dogs

BACKGROUND: Reports of mammary-gland tumors in male dogs are lacking. OBJECTIVE: To describe the clinical characteristics of mammary-gland tumors in male dogs. ANIMALS: Eight male dogs diagnosed with mammary-gland tumors. METHODS: Retrospective study. Medical databases from 3 institutions were searched. Medical records were abstracted, and owners and referring veterinarians contacted for follow-up information. Tissues were reviewed for histologic type, and immunohistochemical staining for estrogen and progesterone receptors (ER, PR) was performed. RESULTS: Eight dogs with histologically confirmed mammary-gland tumors were included in this retrospective study. Median age at diagnosis was 11.5 years. Four dogs were sexually intact; 4 were neutered. All were purebred. Mammary-gland tumors were incidental findings in 7 of 8 dogs. All dogs were treated with only surgical excision. All but 1 dog had benign epithelial tumors. The dog with the malignant tumor was the only dog to develop possible local recurrence but de novo tumor development cannot be excluded. No dog had evidence of metastatic disease at diagnosis. Based on institutional population data, it was determined that female dogs are 62 times more likely to develop mammary-gland tumors than male dogs (P < .001). Estrogen-receptor expression was strong in the majority of tumors; progesterone-receptor expression, although present in all tumors, was less intense. CONCLUSIONS/CLINICAL IMPORTANCE: This study suggests that mammary-gland tumors in male dogs are rare, usually benign, and surgery alone can provide long-term control in most dogs.     

关于方程∑d|nS(d)=φ(n)的可解性

利用初等方法以及Euler函数φ(n)的性质研究了一个包含Smarandache函数与Euler函数的方程的可解性问题,即研究方程∑d|nS(d)＝φ(n)的可解性,证明了该方程有且仅有一个正整数解n＝1.     

基于动态信息反馈的员工绩效管理

员工绩效是受多种因素共同作用的结果,而信息反馈是其中的重要因素。本文首先探讨了激励机制、动态信息反馈与员工绩效的关系;接着构建了动态信息反馈模型,对企业的信息反馈机制进行了深入的分析;最后在动态信息反馈模型的基础上提出了员工绩效管理的一些基本思路和方法,以达到提高员工绩效、增加员工自我意识的目的。     

具多滞量差分方程的振动性

讨论了一性差分方程和非线性差分方程解的振动性。在一定条件下得到动的充分条件，对现有文献中的某些结果进行了改进和推广。