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1.
河北农业大学高水平科技论文统计与分析   总被引:2,自引:0,他引:2  
采用统计分析的方法,对河北农业大学2003--2007年被美国三大英文检索系统收录(SCI、EI、ISTP)和河北农业大学认定的一级学报上发表的学术论文,按总量,学院分布,论文作者年龄、职称、学位分布情况逐一进行了统计分析。分析结果从一个侧面反映了河北农业大学科学研究现状,并对其有关问题进行了探讨。  相似文献   
2.
To evaluate the utility of random-effects linear modeling for herd-level evaluation of trace mineral status, we performed a retrospective analysis of the results for trace mineral testing of bovine liver samples submitted to the Michigan State University Veterinary Diagnostic Laboratory between 2011 and 2017. Our aim was to examine random-effects models for their potential utility in improving interpretation with minimal sample numbers. The database consisted of 1,658 animals distributed among 121 herds. Minerals were assayed by inductively coupled plasma–mass spectroscopy, and included cobalt, copper, iron, molybdenum, manganese, selenium, and zinc. Intraclass correlation coefficients for each mineral were significantly different (p < 0.001) from zero and ranged from 0.38 for manganese to 0.82 for selenium, indicating that the strength of herd effects, which are presumably related to diet, vary greatly by mineral. Analysis of the distribution and standard errors of best linear unbiased predictor (BLUP) values suggested that testing 5–10 animals per herd could place herds within 10 percentile units across the population of herds with 70–95% confidence, the confidence level varying among minerals. Herd means were generally similar to BLUPs, suggesting that means could be reasonably compared to BLUPs with respect to the distributions reported here. However, caution in interpreting means relative to BLUPs should be exercised when animal numbers are small, the standard errors of the means are large, and/or the values are near the extremes of the distribution.  相似文献   
3.
光合有效辐射吸收比率(Fraction of Absorbed Photosynthetically Active Radiation,FPAR)是主要的植物生理参数之一。本研究根据地面实测数据和由HJ-1CCD(Charge-coupled Device,CCD)及Landsat-8OLI(Operational Land Imager,OLI)影像提取的NDVI,分别建立研究区FPAR估算模型,对比分析和评价了CCD和OLI数据在反演研究区FPAR的精度。结果表明,基于CCD和OLI数据计算的NDVI与实测FPAR之间均呈现良好的正相关关系;针对每个基本采样单元(Elementary Sampling Units,ESU),两种数据反演的FPAR具有显著的一致性,且反演值相差甚少;剔除影像中受到云和云影影响的区域,整个研究区利用CCD与OLI数据反演的FPAR相关性好、分布趋势一致,且反演值均值差很小。本研究结果对该区域FPAR的进一步研究具有借鉴和指导意义,在以后的研究中可以尝试使用HJ-1CCD数据。  相似文献   
4.
High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method‐comparison studies, and patient‐based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method‐comparison studies evaluate agreement between techniques or between observers. Patient‐based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross‐sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments.  相似文献   
5.
Zoonotic cutaneous leishmaniasis (ZCL), a vector‐borne disease, poses serious psychological as well as social and economic burden to many rural areas of Iran. The main objectives of this study were to analyse yearly spatial distribution and the possible spatial and spatio‐temporal clusters of the disease to better understand spatio‐temporal epidemiological aspects of ZCL in rural areas of an endemic province, located in north‐east of Iran. Cross‐sectional survey was performed on 2983 recorded cases during the period of 2010–2012 at village level throughout the study area. Global clustering methods including the average nearest‐neighbour distance, Moran's I, general G indices and Ripley's K‐function were applied to investigate the annual spatial distribution of the existing point patterns. Presence of spatial and spatio‐temporal clusters was investigated using the spatial and space–time scan statistics. For each year, semivariogram analysis and all global clustering methods indicated meaningful persistent spatial autocorrelation and highly clustered distribution of ZCL, respectively. Eight significant spatial clusters, mainly located in north and northeast of the province, and one space–time cluster, observed in northern part of the province and during the period of September 2010–November 2010, were detected. Comparison of the location of ZCL clusters with environmental conditions of the study area showed that 97.8% of cases in clusters were located at low altitudes below 725 m above sea level with predominantly arid and semi‐arid climates and poor socio‐economic conditions. The identified clusters highlight high‐risk areas requiring special plans and resources for more close monitoring and control of the disease.  相似文献   
6.
暴发高致病禽流感疫区鸟类禽流感的血清学调查   总被引:1,自引:0,他引:1  
本研究应用血凝抑制试验(H I),2004年初H 5亚型禽流感在中国内地发生前后,于湖北、广西二疫区市县的生态系中,自健康的鹰、鸽子、野鸭和鹌鹑中采集了54份血清,对其进行了血清学检测,并将获得的血清学检测数据进行了统计学分析。分析结果显示,在总共采集的54份血清样品中,抗H 6亚型禽流感病毒(H 6)抗体、抗H 9亚型禽流感病毒(H 9)抗体、抗H 5亚型禽流感病毒(H 5)抗体阳性率分别为64.8%、75.9%、29.6%。推断,这一时期,H 6亚型禽流感病毒(H 6)、H 9亚型禽流感病毒(H 9)和H 5亚型禽流感病毒(H 5)共循环于该生态系中,其中H 9、H 6亚型禽流感病毒长期、稳定循环于该生态系中,为该生态系禽流感主要流行血清型。血凝抑制试验检测结果发现,H 5亚型禽流感病毒抗体滴度较低,最高仅为640×,其阳性率为29.6%,推断其可能为新近传入的病毒或新近重组变异出现的新病毒,可能为与该次禽流感暴发相关的新病毒,这一推断还有待于通过对病毒基因序列的分析而做进一步验证。  相似文献   
7.
A manual kit for determining serum 5'nucleotidase (5'NT, EC 3.1.3.5) activity was adapted for use with rat samples on a large discrete clinical chemistry analyzer. The precision of the method was good (within-run C.V. = 2.14%; between-run C.V. = 5.5%). A comparison of the new automated method with a manual and semi-automated method gave regression statistics of y = 1.18X -3.66 (Sy. x = 4.54), and y = 0.733X + 1.97 (Sy. x = 1.69), respectively. Temperature conversion factors provided by the kit manufacturer for human samples were determined to be inaccurate for converting results from rat samples. Analysis of components contributing to normal variation in rat serum 5'NT activity showed age and sex to be major factors. Increased serum 5'NT activity was observed in female rats when compared to male rats beginning at about 5 to 6 weeks of age. An analysis of variance of serum 5'NT, alkaline phosphatase, and GGT activities observed over a 9-week period in normal rats suggests several advantages for 5'NT as a predictor of biliary lesions in rats.  相似文献   
8.
Pathogens such as Escherichia coli O157:H7 and Campylobacter spp. have been implicated in outbreaks of food poisoning in the UK and elsewhere. Domestic animals and wildlife are important reservoirs for both of these agents, and cross-contamination from faeces is believed to be responsible for many human outbreaks. Appropriate parameterisation of quantitative microbial-risk models requires representative data at all levels of the food chain. Our focus in this paper is on the early stages of the food chain-specifically, sampling issues which arise at the farm level. We estimated animal–pathogen prevalence from faecal-pat samples using a Bayesian method which reflected the uncertainties inherent in the animal-level prevalence estimates. (Note that prevalence here refers to the percentage of animals shedding the bacteria of interest). The method offers more flexibility than traditional, classical approaches: it allows the incorporation of prior belief, and permits the computation of a variety of distributional and numerical summaries, analogues of which often are not available through a classical framework. The Bayesian technique is illustrated with a number of examples reflecting the effects of a diversity of assumptions about the underlying processes. The technique appears to be both robust and flexible, and is useful when defecation rates in infected and uninfected groups are unequal, where population size is uncertain, and also where the microbiological-test sensitivity is imperfect. We also investigated the determination of the sample size necessary for determining animal-level prevalence from pat samples to within a pre-specified degree of accuracy.  相似文献   
9.
对《草业学报》从创刊到1996年发表论文的引文数量、引文语种、引文类型、自引率、衰减系数等进行了统计和分析,结果表明,《草业学报》的引文率为8.46条/篇,引文语种:中文占58.20%,英文占40.91%,此两项测度值均较高;自引率为2.76%,衰减系数为33.96%,均较低;引文类型主要为期刊,占67.86%,其次为图书占28.49%。上述统计与分析,可供作者、读者和编者全面了解、评价和改进《草业学报》质量作为参考。  相似文献   
10.
依据文献计量学的一般方法,对2005-2009年《河北北方学院学报》(自然科学版)出版的30期学报载文的作者信息进行统计,就论文合著率、作者的性别年龄和职称结构、作者地域和机构分布几项指标,对作者群的现状作出分析和评价.分析结果显示,《河北北方学院学报》(自然科学版)论文合著率在逐年提高,社会影响力和传播广度有较大程度的提升,作者分布广泛,拥有一支年轻化、有活力、相对稳定的作者队伍.  相似文献   
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