The efficacy of disinfectant misting in the lairage of a pig abattoir to reduce Salmonella and Enterobacteriaceae on pigs prior to slaughter

Water misting/showers are used in abattoir lairages to improve meat quality, and to cool and calm pigs after transport and during hot weather. One novel approach, which has not been investigated to date, is to add a disinfectant to the misting water as a means of topically reducing Salmonella on pigs prior to slaughter, thereby potentially controlling this organism in the abattoir. The objective of this study was therefore to evaluate misting with water or with Virkonup>®up> S (an approved disinfectant for use in the presence of animals), for their ability to topically reduce Salmonella on high seroprevalence pig herds before stunning and to reduce Enterobacteriaceae.Three experimental groups were investigated: control group (i.e., no misting); water group (misting with cold, 15–17 °C, water, herein referred to as water); and a disinfectant group (misting with 0.5% Virkonup>®up> S). As pigs entered the abattoir, each animal was swabbed along its back before being allocated to its experimental group. Each group was randomly assigned to one of 3 lairage pens that were separated by non-trial pens. After 30 min of misting with water or disinfectant, pigs were moved to the stunning area, where each pig was again swabbed, as above. Swabs were analyzed for the presence of Salmonella and enumeration of Enterobacteriaceae.Before misting, Salmonella prevalence on the pigs was 79.0%, 72.1% and 83.6% for the control, water and disinfectant groups, respectively. After misting, Salmonella prevalence increased to 94.3% in the water group; whereas for the disinfectant group, the prevalence increased marginally to 85.9%. No change in Salmonella prevalence was detected for the control group. In line with the Salmonella results, no significant differences were observed in Enterobacteriaceae counts in the control group at either time point (4.37 and 5.01 logub>10ub> CFU/cmup>2up>, respectively) or in the disinfectant group before and after misting (4.02 and 4.26 logub>10ub> CFU/cmup>2up>, respectively). However, a 2.3 logub>10ub> CFU/cmup>2up> increase in Enterobacteriaceae was recorded for the water group after misting as compared to before misting (p < 0.05).Since misting with water alone increased topical Salmonella contamination on pigs before slaughter, a risk assessment based on known Salmonella data, meat quality and welfare is recommended to determine whether its use is justifiable. On the other hand, the findings from this study suggest that misting with Virkonup>®up> S at 0.5% could have a role in topical antisepsis of pigs contaminated with Salmonella prior to slaughter and as such this warrants further investigation.     

中国古代学校的三种“学规传统”

作为传统教育文化的载体之一,学规蕴含了丰富的教育理念,展现了古代学校的教学和生活情形。十一世纪起,学规被视作是学校管理的一个重要组成部分,官学、书院和蒙学之中形成了相应的“学规传统”。官学学规详订管理规条,具有权威性和惩罚性,缺少对于教学、学习的阐释。这促发了注重劝谕、启发的书院学规传统的诞生,《白鹿洞书院揭示》就是典型的代表作。朱熹等人还开启了以“须知”、“学则”训练儿童道德行为习惯的蒙学学规传统。明清之际,三类学规传统形成定式。钦定“卧碑”、“圣谕”的出现意在管制士子、教化百姓;书院学规以生徒进德立品、读书治学为中心,亦会受到官方教育政策、科考举业和不同学术思想的影响;蒙学学规以训练道德行为和传授基础知识为鹄的,以达“蒙以养正”的“圣功”。     

溶胶-凝胶法合成Gd2O3:Eu纳米晶及荧光性质的研究

采用溶胶-凝胶法合成了Gd2O3:Eu纳米晶.利用X射线衍射,热重及差热分析和荧光光谱等测试手段对Gd2O3:Eu的结晶过程、发光性质进行了研究.XRD结果表明,合成的样品在550℃开始结晶,晶粒随着温度的升高而长大,发光光谱测试表明,宽的主激发峰是由Eu3 电荷迁移态吸收与Gd3 离子的的激发峰重叠而成,主发射峰为610nm,它们的强度随烧结温度的提高而增强.     

从混合模空间到加权Bloch空间的积分算子Cφn,u的有界性和紧性

主要讨论了单位圆盘上从混合模空间到Bloch型空间的积分算子Cφn,u的有界性和紧性,（Cφn,uf）（z）=∫f（n）（φ（ξ））u（ξ）dξ,from 0 to z,u∈H（D）.在文献中讨论了算子IgCφ,JgCφ,让n=1,u（z）=φ′（z）g（z）,Cn,uφ就是IgCφ,让n=0,u（z）=g′（z）,Cφn,u就是JgCφ.在此基础上得到了从混合模空间到Bloch型空间的积分算子的有界性和紧性的充要条件.     

火电厂主厂房建筑三维设计应用与开发

火力发电厂主厂房建筑三维设计内容繁多、过程较复杂,为了保证主厂房内各专业协同设计、有关数据的统一性和唯一性,应使主厂房建筑三维模型建模程序标准化、规范化,明确建模内容和有关分类,解决好数据传递的接口和方式。本文为解决上述问题,进行了较详细的分析和研究,并提出了具体方法和措施,在满足主厂房协同工作的同时,也为后续工作提供必要的数据和背景资料,保证建筑设计文件与主厂房三维模型同步更新,进一步提高建筑设计效率和质量。这将在实际工程中产生明显的设计效率和经济效益。     

类单叶算子的(u+k)轨道闭包

在一定条件下,刻画了类单叶算子的(u+k)轨道闭包,并证明了单叶算子包含在类单叶算子的(u+k)轨道闭包中。     

Effects of ozonation and ultraviolet irradiation on biodegradability of oil shale wastewater organic solutes

Ozonation and u.v. irradiation were evaluated for their abilities to (1) mineralize organic solutes that remained in a biooxidized oil shale process wastewater and (2) effect sufficient structural modification of the remaining biorefractory organic solutes to promote secondary biooxidation. Full-spectrum u.v. radiation (5 h, total dose of 10.2 × 10up>6up> J lup>−1up>) failed to mineralize or effect the biooxidation of any of the biorefractory carbon. Although ozonation (5 h, total dose of 1.6 g Oub>3ub> lup>−1up>) directly mineralized only 8% of the biorefractory carbon, it enhanced secondary biooxidation; 26% of the refractory carbon was mineralized by an acclimated microbial inoculum. When u.v. irradiation and ozonation were combined simultaneously, a synergistic effect was observed; 3 h of combined treatment (5.9 × 10up>6up> J lup>−1up> and 0.83 g Oub>3ub> lup>−1up>) was as effective a pretreatment for secondary biooxidation as was 5 h of ozonation. Sequential application of primary biooxidation, 6 h of combined u.v./ozonation, and secondary biooxidation removed only 59% of the dissolved organic carbon; total reduction of 87% was achieved by using a culture in the secondary biooxidation step that was specifically adapted to this oxidized water. Each time-course sample was analyzed for the distribution of polar and nonpolar organic solutes. In general, ozonation and combined u.v./ozonation mineralized carbon from the nonpolar fraction; biooxidation of formerly refractory carbon was promoted by oxidation of nonpolar carbon to yield more polar or lower-molecular-weight species.     

Disturbance rejecting optimal regulation of hyperbolic systems

Optimal regulation of hyperbolic systems in the presence of unknown exogenous and initial disturbances is considered. Necessary conditions for determining the optimal control that tracks a desired trajectory in the presence of disturbances are developed. These necessary conditions have the form of a twopoint boundary-value problem along with certain equality and inequality conditions. The results also characterize the worst possible disturbances that are accommodated by the optimum controller without any serious performance degradation. Numerical results on the control of a vibrating beam are presented.     

格空间上算子方程组新的不动点定理

在u0-r完备Archimedean型向量格中利用半序的方法研究了一类带有次线性扰动的算子方程组,在非紧非连续的假设下证明了不动点的存在唯一性,并给出了迭代误差估计式.     

On the Complexity of 2-Monotone Restarting Automata

The u4118h728k8148/224_2007_9004_Article_IEq1.gif" alt="$\mathsf{R}$" align="middle" border="0"> -automaton is the weakest form of the nondeterministic version of the restarting automaton that was introduced by Jančar et al. to model the so-called analysis by reduction. Here it is shown that the class ℒ(R) of languages that are accepted by u4118h728k8148/224_2007_9004_Article_IEq2.gif" alt="$\mathsf{R}$" align="middle" border="0"> -automata is incomparable under set inclusion to the class u4118h728k8148/224_2007_9004_Article_IEq3.gif" alt="$\mathsf{CRL}$" align="middle" border="0"> of Church-Rosser languages and to the class u4118h728k8148/224_2007_9004_Article_IEq4.gif" alt="$\mathsf{GCSL}$" align="middle" border="0"> of growing context-sensitive languages. In fact this already holds for the class u4118h728k8148/224_2007_9004_Article_IEq6.gif" alt="$\mathcal{L}(\mbox{2-\textsf {mon-R}})$" align="middle" border="0"> of languages that are accepted by 2-monotone u4118h728k8148/224_2007_9004_Article_IEq7.gif" alt="$\mathsf{R}$" align="middle" border="0"> -automata. In addition, we prove that already the latter class contains u4118h728k8148/224_2007_9004_Article_IEq8.gif" alt="$\mathsf{NP}$" align="middle" border="0"> -complete languages, showing that already the 2-monotone u4118h728k8148/224_2007_9004_Article_IEq9.gif" alt="$\mathsf{R}$" align="middle" border="0"> -automaton has a surprisingly large expressive power. The results of this paper have been announced at DLT 2004 in Auckland, New Zealand. This work was mainly carried out while T. Jurdziński was visiting the University of Kassel, supported by a grant from the Deutsche Forschungsgemeinschaft (DFG). F. Mráz and M. Plátek were partially supported by the Grant Agency of the Czech Republic under Grant-No. 201/04/2102 and by the program ‘Information Society’ under project 1ET100300517. F. Mráz was also supported by the Grant Agency of Charles University in Prague under Grant-No. 358/2006/A-INF/MFF.