The number of replicates,and pooling versus individual measurements for analytical imprecision calculations: Does it matter?     

Fernando Tecles  Alberto Muñoz  José J Cerón  Kathleen Freeman 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2020,49(1):112-118

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Personal and household factors involved in recent Rickettsia exposure in a rural population from Yucatán,Mexico     

Marco Torres‐Castro  Enrique Reyes‐Novelo  Henry Noh‐Pech  Raúl Tello‐Martín  Csar Lugo‐Caballero  Karla Dzul‐Rosado  Fernando Puerto‐Manzano  Roger Ivn Rodríguez‐Vivas 《Zoonoses and public health》2020,67(5):506-515

The aim of the study was to describe the epidemiological factors associated with the risks of recent Rickettsia exposure in inhabitants of a rural population from Yucatán, Mexico. The study included 130 inhabitants from Maxcanú, Yucatán. Blood samples were collected to detect IgM and IgG antibodies against Rickettsia typhi and Rickettsia rickettsii by an indirect immunofluorescence antibody test. Additionally, nested polymerase chain reaction was performed to amplify fragments of the 17kDa and sca5 genes. Previously, an epidemiological questionnaire was applied focused on collecting information on personal and housing exposure variables related to the recent infection with Rickettsia to determine epidemiological associations. Results that exhibited a p‐value < .25 were included in a generalized multinomial logistic linear model to determine the variables involved with the risk of contact or Rickettsia infection. In all, 76% (99/130) of the participants presented with immunoglobulin titres against the Rickettsia species evaluated, while rickettsial DNA was detected in 35.4% (46/130) of the participants. The association analysis with the personal exposure variables showed that the productive age group (OR = 0.32; 95% CI = 0.10–1.03) and the elders group (OR = 0.12; 95% CI = 0.01–0.83) were protective factors for recent infection with R. typhi, taking as reference the school group. The presence of a family orchard in the home (OR = 7.56; 95% CI = 1.62–35.29) was a risk factor for recent infection with R. rickettsii. Presumably, the presence of ectoparasites (OR = 2.71; 95% CI = 0.90–8.09) at home was a risk factor for recent infection with both Rickettsia species. Recent infection was demonstrated in inhabitants from Maxcanú, Yucatán. A high seropositive frequency was obtained. The results highlight the importance of the family garden and the presence of ectoparasites in the home as risk factors associated with recent infection with Rickettsia in inhabitants from Maxcanú.  相似文献   

论新农村建设与农村宅基地合理利用   总被引：13，自引：1，他引：13  

陈士银  周飞  吴明发 《安徽农业科学》2007,35(14):4354-4356,4396

从农村宅基地利用管理的角度出发,总结了新农村建设对我国农村宅基地利用与管理的新要求,分析了我国农村宅基地利用与管理的现状及存在的主要问题,并提出通过改革现行农村宅基地产权制度、完善管理制度和促进宅基地合理利用的对策措施来加强农村宅基地的利用与管理,以适应社会主义新农村建设的需要。  相似文献   

草莓株体年生长动态的研究     

辛培刚  王存喜 《山东农业大学学报(自然科学版)》1988,(3)

将草莓分为无性株系和母体单株两类分別调查,則无性株系总鲜重、叶鲜重、叶面积增长动态皆为S型曲线,由此曲线公式可计算出最大生长速度出现时间为8月中下旬,并可求算出最大生长速度及最大速度时的生长量。无性株系的新根鲜重及吸收面积动态基本一致,皆为具三次波峰的曲线,高峰分别在4月中、7月下10月底出现,最后一次高峯持续时间较长。而无性株系的变(褐)色根的年动态变化为一开口向上的抛物线。母体单株的鲜重、地上部干、鲜重、叶鲜重等均为开口向下的抛物线;而其根鲜重年内有三次波峯,分別在4月中旬、7月上旬和10月下旬,以中间的波峯持续时间较长。  相似文献   

基于分层贝叶斯方法的高山松单木生物量模型     

黄金君  舒清态  王柯人  席磊  孙杨  罗浩 《西北林学院学报》2022,37(3):126-132

以香格里拉市典型森林生态系统高山松林为对象,在前期进行Ⅰ区和Ⅱ区共115株高山松单木地上生物量实测基础上,以异速生长方程为单木生物量基础模型,并采用分层贝叶斯方法、非线性混合模型法、贝叶斯方法和非线性最小二乘法进行异速生长参数拟合,运用决定系数(R²)、估测精度(E)、均方根误差(RMSE)等指标对模型参数拟合效果进行评价。结果表明:1)从拟合精度看,4种方法的模型拟合效果均较好,R²均达到了0.98以上。但分层贝叶斯方法估计结果更优,其R²=0.985 6,E=84.76%和R_MSE=39.75 kg;2)通过对比不同方法的差异发现,加入了区域随机效应的分层贝叶斯方法和非线性混合模型法的拟合效果均优于未加入区域随机效应的贝叶斯方法和非线性最小二乘法。分层贝叶斯方法在拟合高山松单木生物量模型中具有更大优势,模型拟合效果最好。加入了随机效应的分层贝叶斯方法和非线性混合模型法可以提高单木生物量模型的估计精度,采用分层贝叶斯方法进行高山松单木生物量模型参数估测,为大尺度样本数据模型参数估测方法提供新思路。  相似文献   

高校图书馆个性化信息服务探究   总被引：6，自引：0，他引：6  

侯福丽 《农业图书情报学刊》2007,19(3):45-46,64

分析了国内外高校图书馆个性化信息服务发展的现状，指出国内高校图书馆个性化信息服务存在的问题，提出了高校图书馆实现个性化信息服务的策略。  相似文献   

关于中国农村宅基地使用权流转问题的探讨     

江辉  焦卫平  路婕  徐丹 《勤云标准版测试》2007,(12)

农村宅基地使用权流转问题是我国土地管理中的热点和难点。笔者以农村宅基地为研究对象,对宅基地使用权流转进行了探讨。文章阐述了农村宅基地使用权流转现状和存在的问题,并分析其产生问题的原因,最后提出了完善宅基地使用权流转的一些建议,以期宅基地流转逐渐走向制度化、规范化和法制化。  相似文献   

冬前高温和播期密度对小麦苗期个体及群体生长的影响     

梁志刚  王娟玲  崔欢虎  王裕智  靖华 《勤云标准版测试》2007,(8)

在山西临汾采用连续递增密度试验小区设计法,开展了播期密度对小麦苗期个体和群体生长的影响研究。结果表明,在冬前气温偏高的年型条件下,播种密度在225￣450万粒/hm2范围内,随着播种密度的增加株高增加,单株茎数、单株次生根数、单株绿叶数减少并存在显著性差异,而主茎叶龄则无显著性差异;播种期在9月24日￣10月4日范围内,株高、主茎叶龄和单株次生根3个性状均随播种期的推迟株高降低、主茎叶龄和单株次生根减少,单株茎数和绿叶均为9月29日播种的居多;播种期和播种密度对株高、主茎叶龄、单株茎数、单株次生根数和单株绿叶性状的变异系数影响不同。9月24日和9月29日播种的4个播种量冬前群体均分别不足1200万/hm2和超过了1200万/hm2。本试验达到壮苗和合理群体指标的组合为播期10月4日、播种量225万/hm2。  相似文献   

滩地淹水胁迫对杨树生长与木材显微结构的影响   总被引：7，自引：1，他引：7  

汤玉喜  刘友全吴立勋吴敏 《中南林学院学报》2005,25(6):29-33

对5种不同淹水时间类型滩地1～10年生杨树单株材积生长动态进行了分析．结果表明。不同类型之间单株材积生长量均存在显著差异．且随着林龄增长，其差异逐步减小；不同淹水胁迫下，当年年轮宽度、纤维细胞数量、木材基本密度均存在显著差异，纤维长度和宽度差异不显著，杨树年轮宽度与径向纤维细胞数、导管数、径向纤维比量呈正相关；随淹水胁迫程度加深，当年形成层细胞分裂受到了显著抑制，纤维细胞以及导管数量减少，林木径向生长量下降．径向导管比量提高，纤维比量下降，细胞壁腔比减小，木材密度明显降低．对5种淹水类型滩地的林木生长进行了系统聚类，合并划分为4种生长类型，对其中3种常规造林宜林类型杨树生长潜力进行了预测。  相似文献   

Research of New Housing Design Leaping over the Era     

Jia Yao- chai 《保鲜与加工》1996,(3):15-23

Housing design in Chinese cities has reached a new summit since the middle of 1980's.In the past decade,great changes have taken place about conception and method of housing design.During the alternation of two centuries,people pay much more attention to the new housing design.This paper is concerned with the conception and principle of new housing design and architectural pattern of new housing. The design conception,of coexistence between housing and environment and the balance of ecosystem,should be set up in design of the new housing leaping over the era.We should consider human being as the core of housing design,improve the quality of housing environment adaptability and changeableness of housing to make housing grow with the development of living- pattern and society.The Architecture pattern of new housing in the period of nineth five year plan is as follows: The housing which save the land,energy and material.The living- style housing with complete function and all necessary fittings;adaptable and changeable house,with household participation;The growing- style housing completed gradually.  相似文献