Effect of road density on abundance of white-footed mice

While several studies have demonstrated that roads can act as barriers to small mammal movement, the relationship between road density and small mammal abundance has not yet been investigated. In southeastern Ontario, Peromyscus leucopus (white-footed mice) suffer high over-winter mortality rates, resulting in small springtime populations and frequent local extinctions. Peromyscus leucopus movement is known to be inhibited by roads, which should result in lower rates of immigration into and recolonization of habitats in landscapes with high road density. We tested two predictions: (1) Forest sites situated in landscapes with high road densities have a higher chance of P. leucopus being absent during the early spring than forest sites situated in landscapes with low road densities and (2) P. leucopus populations during the summer are smaller in forest sites situated in landscapes with high road densities than in landscapes with low road densities. We sampled P. leucopus in focal patches within nineteen landscapes (7 rural, low-road-density landscapes; 7 rural, high-road-density landscapes; 5 urban landscapes). There was no significant relationship between road density and the presence/absence of P. leucopus during the early spring. We found a significant positive effect of road density on P. leucopus relative abundance during the summer, even when we excluded the urban landscapes and based the analysis on only the 14 rural landscapes. Our results suggest that any negative effect of roads on P. leucopus populations, created by their inhibition to moving across roads, is far outweighed by some positive effect of roads on P. leucopus abundance. We suggest that the two most likely explanations are that roads are positively correlated with an important as-yet-undetermined component of habitat quality, or that roads positively affect P. leucopus by negatively affecting their predators.     

花后温度和湿度条件对台农1号杧坐果率的影响

为探索杧果坐果率与开花后温度和湿度条件的关系,以台农1号杧为试材,应用生物统计学方法计算分析了80个温度和湿度自变量与不同时期坐果率的相关关系。结果表明:(1)花后14d的坐果率受温度和湿度条件影响最大。(2)花后7d两性花坐果率与花后1～6d平均空气相对湿度呈显著直线线性负相关,与花后1～2d、1～4d、1～6d的平均最高温度、平均温度、平均最低温度、>10℃积温无显著相关关系。(3)花后14d坐果率与花后6～10d的平均最高温度、4～10d平均温度、2～10d平均最低温度、4～14d>10℃积温呈显著或极显著的直线相关;与花后1～14d平均最高温度、平均温度呈显著的多项式线性相关;与花后1～14d平均空气相对湿度呈极显著的直线线性负相关。(4)花后25d坐果率与花后1～10d的平均最高温度、平均温度、>10℃积温以及花后1～14d平均最高温度呈显著的多项式线性相关。(5)有利于花后14d坐果的花后4～14d的下限平均温度为20.6℃,最适温度为24.7℃。     

Catecholamine and cortisol responses of horses to incremental exertion

The responses of the plasma concentrations of catecholamines and cortisol in horses to varied relative intensities of exertion were examined. The plasma concentrations of cortisol, epinephrine and norepinephrine increased significantly (p<0.05) with exertion. The plasma cortisol concentrations at relative work intensities of 48.3%±1.4%, 82.3%±2.0% and 99.6%±0.4% of VO_2max were 114%, 124%, and 126%, respectively, of those at rest, whereas the plasma epinephrine concentrations were 239%, 772% and 3483%, and the norepinephrine concentrations were 138%, 255%, and 1121% of the values at rest. There was a significant (p<0.0001) relationship between the plasma epinephrine and norepinephrine concentrations. The blood lactate concentration and the plasma epinephrine and norepinephrine concentrations were significantly (p<0.0001) related, as were the relative work intensity (%VO_2max) and the plasma epinephrine and norepinephrine concentrations. The relationships between the plasma cortisol concentration and work intensity or blood lactate concentration were not significant (p>0.05). This study demonstrates a relationship between relative work intensity and indicators of adrenal medullary and sympathetic activity during brief exertion in horses.     

Factors Associated with Survival in Septicemic Foals: 65 Cases (1988–1995)

In order to identify variables obtained at admission that could be used to predict survival in septicemic foals, medical records of 65 foals diagnosed with septicemia were reviewed. Initially, variables were analyzed independently (univariate analysis) for association with survival. Of the physical examination and historical data examined using univariate analysis, the ability to stand at admission, respiratory rate ≥ 60 breaths per minute (bpm), and normal-appearing mucous membranes were significantly associated with survival. Foals with history of induced parturition were significantly less likely to survive. The following hematologic and serum biochemical variables determined at admission were significantly associated with survival: white blood cell count a 6,000 cells/μL, neutrophil count <4,000 cells/μL, serum albumin concentration <2.2 g/dL, serum glucose concentration <120 mg/ dL, blood pH ≥ 7.35, and positive base excess. The administration of plasma at admission was significantly associated with survival. Stepwise multiple logistic regression analysis was performed to evaluate the association between survival and variables identified as significantly associated with survival in bivariate analysis. The final multivariate model selected included the variables standing, duration of clinical signs (24-hour intervals) prior to admission, respiratory rate a 60 bpm, neutropenia (> 4,000 cells/μL), and neonatal age category. The probability of survival was significantly increased for foals that were standing, had a respiratory rate a 60 bpm, and that had a neutrophil count <4,000 cells/μL at admission. Probability of survival was significantly decreased for foals that had a longer duration of clinical signs prior to admission. For each 24 hours of duration, the estimated risk of death was increased by 5.8-fold.     

双峰驼精清及其活性组分凝集素寡糖的初步研究

应用植物血凝素与寡糖结构相同或相似的糖复合物专一凝集的原理与方法,结合小鼠排卵试验,间接观察了公驼精清及其经ＤＥ－５２离子交换层析和高效液相层析提取分离的活性组分的蛋白组成。结果表明,公驼精清内糖蛋白含有２种以上的寡糖,其内的活性组分及诱导排卵因子与所试植物血凝素不发生反应     

欠发达地区旅游业可持续发展技术路径选择研究

结合欠发达地区旅游业发展特点和经济学竞争优势相关理论认为,欠发达地区旅游业可持续发展通常遵循以下技术路径:即起步阶段充分发挥区域资源的绝对优势或比较优势,赢得起步发展空间;中期阶段充分利用后发优势,加速产业升级,实现跨跃式发展;成熟阶段加强资源整合,培育区域旅游业可持续发展的核心竞争优势。     

高温条件下复合抗应激剂对肉鸡的影响

本文研究了高温条件下复合抗应激剂对肉鸡的影响。结果表明：经历３２ ℃一周的５ ～８ 周龄肉鸡采食量、增重、饲料转化率均显著下降（Ｐ＜ ０ ．０１） ，饮服复合抗应激剂显著改善增重和饲料转化率（Ｐ＜ ０ ．０１） ， 采食量未见明显改变，饲料转化率达到常温水平。３２ ℃１６ 小时血浆皮质酮、Ｔ３ 显著下降（Ｐ＜ ０ ．０１） 、Ｔ４ 显著升高（Ｐ＜ ０ ．０１） ；３２ ℃１２０ 小时血浆皮质酮、Ｔ３ 升高并超出常温组（Ｐ＜ ０ ．０５） 、Ｔ４ 较１６ 小时下降但仍高出常温组（Ｐ＜ ０ ．０５） 。饮服复合抗应激剂时血浆皮质酮、Ｔ３ 、Ｔ４ 显现相同变化规律，但这种变化得到显著缓解     

等离子体聚合法制备聚二乙胺

以二乙胺为单体，采用等离子聚合法，在盖破片等基片上制得了稳定性和附着性均好的聚二乙胺膜，考察了聚合工艺参数对聚合物性状及表现形貌的影响，红外光谱与元素分析结果表明聚合膜的结构具有高度支化与交联特征，且聚合膜中有－ＮＨ２和（或）＝ＮＨ基团。     

K均值和分层聚类法在大米产地鉴别中的应用

大米称誉为"五谷之首",是我国的主要粮食作物。大米产地鉴别方法的研究对于保护广大消费者和生产厂家的利益、推动我国大米出口业的发展等都具有重要意义。为此,选取了19个响水大米样品和10个非响水大米样品,使用等离子体原子发射光谱的方法测定了样品中P,B,Zn,Fe,Cu,Mn,Na,K,Mg和Ca等10种微量元素的含量,并利用样品中的微量元素含量数据,使用K-Means聚类法和Hierarchical聚类法对大米样品进行了聚类分析。结果表明,K-Means和Hierarchical聚类法对于样品有聚类趋势。研究结果能够为大米生产厂商与质检部门鉴别大米产地提供参考和借鉴。