Leslie矩阵模型在油松毛虫种群动态分析中的应用研究   总被引：4，自引：0，他引：4  

张素芬 《林业科学》1991,27(4):470-474

油松毛虫(Dendrolimus tabulaeformis)是我国华北地区油松林的重要害虫之一。其分布面积广、发生频繁、危害严重。有人曾对油松毛虫种群的生物学特性、防治以及种群动态的研究作过有关的报道,本文则通过对油松毛虫的数量变动进行跟踪调查,并用Leslie矩阵模型对其种群动态进行了模拟,这对害虫的测报具有重要的实践意义。一、材料与方法 (一)标准地概况 1984—1986年与1988—1989年我们分别在密云县五座楼场和石墙沟村选择了5块油松纯林作为标准地,概况列在表1中:  相似文献   

国家林业局工作组赴吉林、黑龙江检查森林防火工作情况的报告     

赴吉林 《森林防火》2007,(2):1-3

2007年5月13~23日,在全国政协委员、国家森林防火指挥部森林防火专家组组长、国家林业局原副局长马福同志带领下,我们一行4人对吉林和黑龙江省2007年春季森林防火工作进行了检查调研。在检查过程中,针对当前森林防火形势、防  相似文献   

落叶松落叶病预测预报技术的研究     

刘国荣  王世君 《林业科学》1992,28(3):220-225

我们通过对气象因子与落叶松落叶病发病关系的研究,和对入选的主要气象因子在各月份中作用的分析,将六七月份降水量、平均相对湿度和四五月份平均气温确定为病情测报因子。其当年值预测式为y=b_0+b_1x_1+b_2x_2……+b_(12)x_(12)(x_1、x_2……x_(12)为前1—12年测报因子观测值;b_0、b_1……b_(12)为相应回归系数);由23年全省历史资料建立的病情指数预测式为y=68.31-1.68x_1-0.5638x_2+0.36x_3(x_1、x_2、x_3分别为气温、湿度、降水预测值);全省发病面积预测式为y=(-0.13325+0.00533x)Sy(式中,x为病情指数预测值;Sy为全省幼龄落叶松人工林面积)。根据各地区发病面积比例系数和各地区轻、中、重发病面积的百分比,可预测各地区发病面积和轻、中、重发病面积。应防治面积为重、中级发病面积与20％轻病级面积之和。  相似文献   

湖北省核桃品种资源和栽培区划   总被引：3，自引：1，他引：3  

湖北省核桃课题协作组 《经济林研究》1996,14(1):7-9

本文概述了湖北省核桃的栽培现状和生境条件，以及核桃品种资源及其分布，提出了湖北省核桃栽培区划。还对发展核桃生产的有关经营方向和措施进行探讨。  相似文献   

Surveillance of Human Rabies by National Authorities – A Global Survey          下载免费PDF全文

L. H. Taylor  L. Knopf  the Partners for Rabies Prevention 《Zoonoses and public health》2015,62(7):543-552

Effective prevention of deaths due to human rabies is currently hampered by a lack of understanding of the scale of the problem, and the distribution of both animal and human cases across countries, regions and continents. Unfortunately, despite the severity of the disease, accurate data on which to assess these questions and to prioritize and direct public health interventions are not available for many parts of the world. This survey sought to understand the current global situation regarding the surveillance of human rabies. Data were collected from 91 countries across all continents and all categories of human rabies risk, generating the most complete and representative global data set currently available. Respondents were asked key questions about whether human rabies was a notifiable disease, how the surveillance system for human rabies operated and whether the respondent considered that the surveillance system was working effectively. Across the 91 countries from which data were collated, human rabies was a notifiable disease in all but eight. Despite international guidance, surveillance systems were very varied. Even where rabies is a notifiable disease, many countries had surveillance system judged to be ineffective, almost all of these being high and moderate rabies risk countries in Africa and Asia. Overall, 41% of the population covered by this survey (around 2.5 billion people) live in countries where there is no or ineffective rabies surveillance. The lack of robust surveillance is hindering rabies control efforts. However, whilst worldwide rabies surveillance would be improved if rabies were notifiable in all countries, many other challenges to the implementation of effective global human rabies surveillance systems remain.  相似文献   

Demographic factors associated with the diet quality of older US men: baseline data from the Osteoporotic Fractures in Men (MrOS) study     

Shannon J  Shikany JM  Barrett-Connor E  Marshall LM  Bunker CH  Chan JM  Stone KL  Orwoll E;Osteoporotic Fractures in Men 《Public health nutrition》2007,10(8):810-818

OBJECTIVE: Throughout the world, the proportion of the male population aged 65 years and older is increasing. Yet, we have limited information regarding diet quality and predictors of diet quality in this segment of the population. The objectives of the current analyses are to describe the diet quality of a cohort of men >65 years of age, and identify lifestyle factors associated with poor diet quality. METHODS: We present a cross-sectional analysis of the diet quality of 5928 men, aged 65-100 years, who are participants in the Osteoporotic Fractures in Men (MrOS) cohort study. Dietary intake was determined using a modified Block 98 food-frequency questionnaire. Diet quality was calculated using the previously validated Diet Quality Index-Revised (DQI-R). Univariate and multivariate modelling was used to estimate the variance in diet quality predicted by a number of sociodemographic factors, including age, race/ethnicity, body mass index (BMI), marital status, education, smoking status, physical activity, self-perceived health and nutritional supplement use. RESULTS: Overall, we found that in this geographically diverse group of older men, diet quality was low, with a mean modified DQI-R for the entire study population of 62.5 (standard deviation 13.1) out of an ideal of 100. Further, younger age, very low total calorie intake (< or = 1187 kcal day- 1), higher BMI, residence in a North or Southeast community, being of African-American or Hispanic race, being less educated, not using dietary supplements and smoking were each significant independent predictors of a poorer diet. CONCLUSION: These data may prove useful in both understanding the dietary intake of older US men as it relates to published dietary guidelines, and for targeting future dietary intervention programmes.  相似文献   

Do early infant feeding practices vary by maternal ethnic group?     

Griffiths LJ  Tate AR  Dezateux C;Millennium Cohort Study Child Health Group 《Public health nutrition》2007,10(9):957-964

OBJECTIVE: To examine UK country and ethnic variations in infant feeding practices. DESIGN: Cohort study. SETTING: Infants enrolled in the Millennium Cohort Study, born between September 2000 and January 2002. SUBJECTS: A total of 18 150 natural mothers (11 286 (8207 white) living in England) of singleton infants. OUTCOME MEASURES: Breast-feeding initiation, breast-feeding discontinuation and introduction of solid foods before 4 months. EXPLANATORY VARIABLES: Maternal ethnic group, education and social class. RESULTS: Seventy per cent of UK mothers started to breast-feed, of whom 62% stopped before 4 months. Median age at discontinuing breast-feeding was 14, 13, 10 and 6 weeks in Scotland, England, Wales and Northern Ireland, respectively. Thirty-six per cent of UK mothers (34% in England) introduced solids before 4 months. White mothers were more likely to discontinue breast-feeding (62%) and introduce solids early (37%) than most other ethnic minority groups; those stopping before 4 months were more likely to introduce solids early compared with those continuing to breast-feed beyond this age (adjusted rate ratio (95% confidence interval): 1.3 (1.1-1.2)). Educated mothers were less likely to stop breast-feeding before 4 months (white mothers, 0.8 (0.8-0.9); non-white mothers, 0.9 (0.8-1.0)) than those with no/minimal qualifications but, among ethnic minorities, were more likely to introduce solids early (1.3 (1.0-1.6)). Socio-economic status was positively associated with breast-feeding continuation among white women, and with age at introduction of solids among non-white women. CONCLUSIONS: We have identified important geographic, ethnic and social inequalities in breast-feeding continuation and introduction of solids within the UK, many of which have not been reported previously. The factors mediating these associations are complex and merit further study to ensure that interventions proposed to promote maternal adherence to current infant feeding recommendations are appropriate and effective.  相似文献   

Phenotypic and genotypic background underlying variations in fatty acid composition and sensory parameters in European bovine breeds     

Natalia Sevane  Hubert Leveziel  Geoffrey R Nute  Carlos Sanudo  Alessio Valentini  John Williams  Susana Dunner  the GeMQual Consortium 《畜牧与生物技术杂志(英文版)》2014,(2):154-162

Background： Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients, in this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated. Methods： A sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids （FA） profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used. Results： The correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA （PUFA） were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between fiavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis （PCA） mainly reflects their known trait associations, although influenced by their specific breed allele frequencies. Conclusions： The results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic information on polymorphisms previo  相似文献   

牛膝细胞转化苗的田间培植     

郑州牧专牛膝课题组 《郑州牧业工程高等专科学校学报》1999,(1)

经过近1年的实验室工作,于1997年5月得到发育良好的牛膝细胞转化苗.1997年6月将室内培植14日的6棵幼苗移栽至田间.种植1O日后去弱保留3棵.1997年1O月收获种子.一部分留样,一部分于1998年5月进行田间播种,扩大种植.  相似文献   

Fangat Khamatovich Khaziev is 70     

Institute of Biology of the Ufa Research Center of the Russian Academy of Sciences 《Eurasian Soil Science》2006,39(6):689-690

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