襄樊保康野生蜡梅资源及园林应用

通过对襄樊市保康县野生蜡梅资源的研究状况与园林应用等分析研究,指出了保康县野生蜡梅资源园林应用技术研究的途径,提出了利用保康县野生蜡梅资源优势因地制宜打造襄樊特色景观的构思。     

县域生态经济发展模式研究——以湖北省保康县为例

根据保康县自然条件和资源特点,分析提出了保康县生态经济＂三位一体＂发展模式,即花茶联合深加工子模式、磷资源垂直加工子模式、旅游有机结合子模式。针对保康县生态经济发展存在的问题,提出了优化保康县生态经济发展的对策建议。     

湖北省保康县生态经济发展模式研究

生态经济是指生态系统与经济系统共同形成的复合系统,具有生态与经济的双重特性。根据保康县自然条件和资源特点,分析提出了保康县生态经济"三位一体"发展模式,即花茶联合深加工子模式,磷资源垂直加工子模式,旅游有机结合子模式。针对保康县生态经济发展存在的问题,进一步提出优化保康县生态经济发展的对策措施     

湖北省保康县统筹区域土地利用功能分区的研究

以湖北省保康县为例,对土地利用总体规划中统筹区域土地利用规划专题的功能分区进行研究.所涉及到的数据均来自湖北省保康县(注:只作为参考教据).     

保康县国家重点保护野生植物名录与分布

对保康县分布的国家重点保护野生植物进行了调查。结果表明:保康县的国家重点保护野生植物共有29种,占湖北省总数57种的50.88%,是湖北省野生植物保护的重要区域。其中一级7种(栽培2种),二级22种(栽培2种)。并对这些重点保护植物的大致分布情况作了介绍。     

湖北省保康县统筹区域土地利用功能分区的研究

以湖北省保康县为例,对土地利用总体规划中统筹区域土地利用规划专题的功能分区进行研究。所涉及到的数据均来自湖北省保康县(注:只作为参考数据)。     

用共产党员的忠诚拓出小康路——孙开林在清华大学的演讲

保康县尧治河村党支部从1988年开始带领群众劈山修路、筑坝发电、开发矿山,实现了由"贫困村"向保康县"首富村"的跨越。我们编发此文意在使读者朋友进一步了解、学习尧治河人战天斗地、不怕牺牲,在逆境中奋起的高贵品质。     

山区烟叶生产技术推广问题的探析——以保康县烟叶生产技术推广为例

本文以保康县烟叶生产技术推广为例,对适合山区技术推广新模式进行了探索。     

药王带富一大批

在湖北保康县大山深处的寺坪镇,十里八户的农民都得过他的帮助,全镇有3000多户在他的帮助下,每户年收入过万元,最高的年收入8万多元。他就是保康县寺坪镇药材经销大户柳长礼。     

毁坏油菜一亩五 换来徒刑二年半

只因邻居摘了自家的金银花,王某便采取毁田、威胁的手段疯狂进行报复。近日,湖北省保康县法院以破坏生产经营罪判处王某有期徒刑二年零六个月。2005年5月2日下午5时许,保康县马良镇长岭湾村村民王某外出回家时,看见邻居村妇周某在他家的责任田边坎上摘野生金银花。王某即指责周     

猴头杜鹃种群结构和分布格局研究

研究浙江省凤阳山猴头杜鹃(Rhododendron simiarum)种群的大小级、存活曲线和分布格局,结果表明:不同样地猴头杜鹃的年龄结构不同,有稳定型或增长型、稳定型趋向衰退型以及衰退型等,总体上多数样地猴头杜鹃种群幼苗库数量较为丰富,种群年龄结构为稳定型,猴头杜鹃种群在群落中能得到稳定的发展。猴头杜鹃种群的分布格局呈集群型,这是由物种本身生物学特性和环境条件的综合影响所决定的。     

梭鱼养殖群体与自然群体的遗传结构研究

[目的]掌握渤海地区梭鱼种群的种质资源状况。[方法]应用随机扩增多态DNA(RAPD)技术,对梭鱼养殖群体与自然群体的遗传多样性进行了分析。[结果]从45个随机引物中选出20个扩增效果稳定的引物进行群体分析。其中,梭鱼自然群体共检出了204个扩增位点,多态位点136个,多态位点比例为66.7%;养殖群体中共检出了217个扩增位点,多态位点130个,多态位点比例为59.9%。[结论]目前梭鱼群体的遗传多样性较为丰富,人工养殖还未对其造成明显的影响。     

辣椒DH群体果实性状的分离及与F2群体的比较

为分析DH群体的遗传稳定性及其DH群体内性状分离与同来源的F2群体之间异同,本研究利用辣椒花药培养技术,构建一个由“羊角椒(97403)×方灯笼甜椒(97410)”的杂交而成的牛角椒组合作为供体的且由103个DH系组成的DH群体,对该DH群体进行单果重等5个主要果实性状的遗传表现进行分析,并与同来源的F2群体进行比较。结果表明:原供体及其双亲的5个果实性状的变异系数均较小,三者之间的各性状均存在显著差异,说明原供体及其双亲的整齐一致性;对DH群体和F2群体各性状的平均值、变异系数及其性状分离区间的分析和对比结果表明,5个果实性状均是受多基因控制的数量性状,且由于基因重组无论是DH群体还是F2群体均能产生正向和负向两个方向的超亲基因型。但DH群体与F2群体比较各性状的分离区间明显增大,超亲分离类型明显增加,且获得的各DH系均为稳定遗传的自交系,提高了花培育种的选择效率。     

种群遗传学研究进展

主要分析扩散、环境因子和渐渗杂交对种群遗传结构的影响以及边缘种群遗传多样性等方面的研究进展。     

America's Soaring Prison Population

Factors widely reported to explain record prison population increases since 1973 were generally not substantiated in national data. No clear evidence was found that prosecutors were increasingly using mandatory prison sentencing laws, that judges were imposing longer prison sentences than previously, or that parole boards were making prisoners serve longer before their first release. Changes since 1973 in population demographics and in police-recorded crime and arrest rates were found to have only a modest impact on prison population growth. The war on drugs was found to have only a small impact despite increased drug arrest and imprisonment rates. One change found to have a major impact was the increased chance of a prison sentence after arrest for nearly every type of crime. This change has helped to drive incarceration rates to their highest levels ever. Accompanying rising incarceration rates have been gradual reductions in U.S. crime rates after 1973, according to annual crime victimization surveys. The possibility that rising incarceration rates are helping to reduce crime must be weighed in debates about America's prisons.     

年龄结构种群模型的研究进展

综述了年龄结构种群模型的研究进展与研究这类问题的多种数值方法,并就年龄结构种群模型未来的研究重点和需要解决的问题进行了展望。     

长白山自然保护区中国林蛙种群现状及增殖措施

分析了长白山自然保护区中国林蛙种群的现状,观察了在采用相应措施的情况下林蛙种群的增长情况.结果表明：长白山自然保护区林蛙种群结构保持幼蛙占多的格局,但种群统计数量较过去已明显减少,同时林蛙个体大小的总体水平也已不如过去.采用为林蛙创造适宜繁殖生境和补充种源、加强放养管理等措施,可有效地促进林蛙种群的增长进程.     

Population cycles in small rodents

We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive potential and are able to exploit a new environment rapidly. Dispersing voles seem to be r strategists. Young females in breeding condition were over-represented in dispersing female Microtus (17). The Tf(C)/Tf(E) females, which were more common among dispersers during the phase of population increase (Fig. 6), also have a slight reproductive advantage over the other Tf genotypes (19). Thus in Microtus populations the animals with the highest reproductive potential, the r strategists, are dispersing. The segment of the population which remains behind after the selection-via-dispersal are those individuals which are less influenced by increasing population densities. These are the individuals which maximize use of the habitat, the K strategists in MacArthur and Wilson's terminology, or voles selected for spacing behavior. Thus we can describe population cycles in Microtus in the same theoretical framework as colonizing species on islands. Our work on Microtus is consistent with the hypothesis of genetic and behavioral effects proposed by Chitty (6) (Fig. 7) in that it shows both behavioral differences in males during the phases of population fluctuation and periods of strong genetic selection. The greatest gaps in our knowledge are in the area of genetic-behavioral interactions which are most difficult to measure. We have no information on the heritability of aggressive behavior in voles. The pathways by which behavioral events are translated into physiological changes which affect reproduction and growth have been carefully analyzed by Christian and his associates (28) for rodents in laboratory situations, but the application of these findings to the complex field events described above remains to be done. Several experiments are suggested by our work. First, other populations of other rodent species should increase to abnormal densities if enclosed in a large fenced area (29). We need to find situations in which this prediction is not fulfilled. Island populations may be an important source of material for such an experiment (30). Second, if one-way exit doors were provided from a fenced area, normal population regulation through dispersal should occur. This experiment would provide another method by which dispersers could be identified. Third, if dispersal were prevented after a population reached peak densities, a normal decline phase should occur. This prediction is based on the assumption that dispersal during the increase phase is sufficient to ensure the decline phase 1 or 2 years later. All these experiments are concerned with the dispersal factor, and our work on Microtus can be summarized by the admonition: study dispersal.     

农村女性人口素质与未来人口素质的关系

妇女是人口再生产的主要承担者,当前我国城乡妇女生育状况表明,农村母亲对人口再生产的作用明显增强,城市母亲对人口再生产作用下降,而农村女性人口的素质状况堪忧.农村女性人口素质不仅关系到农村未来人口素质,而且关系到整个国家未来人口素质,提高农村女性人口素质十分迫切.提出目前提高农村女性人口素质的重点是:提高农村女性人口的文化水平,提高农村妇女家庭教育能力,引导农村妇女学习市场经济知识,确立与时代发展相适应的思想观念,提高农业科技水平.提高农村女性人口素质的途径是:政府、群团组织、事业单位各自发挥应有的作用;充分发挥各种媒体的作用,特别是发挥电视、网络、图书和报刊的作用.     

New Grouped Harvesting-Based Population Structures of Cotton

The construction of rational population structures is an important cultivation basis to achieve high yield and quality of cotton. ‘Small-sized plant under high plant density’, ‘moderate-sized plant under moderate plant density’ and ‘large-sized plant under low plant density’ are three types of traditional cotton population structures in China, which have been widely used in China's major cotton planting regions of Northwest inland, Yellow River and Yangtze River valley, respectively, and have played key roles in achieving stable and high yields of cotton in the nation. However, in the new era of cotton industry development, there occur such disadvantages that the traditional population structures are not suitable for grouped harvesting as well as both fiber quality and production efficiency improvements. The exploration of new population structures has become an important approach in the new period of cotton cultivation. In this paper, we concisely reviewed the main features and the disadvantages of traditional population structures. Based on the needs of light and cost-saving cultivation as well as quality improving and efficiency increasing in the new era, it was suggested that constructing 3 new types of population structures adapted to grouped harvesting, ‘reduced plant density with healthy plants’, ‘increased plant density with robust plants’, and ‘direct seeding and close planting with short plants’ to substitute the three traditional structures. On this basis, the key indicators and regulation technologies of the 3 new population structures were mainly discussed, and the future development of the new population structures both in research and practice were also prospected.