污染环境中种群的最优收获问题

研究了污染环境中可再生资源的最优收获问题，利用Pontryagin极大值原理，得到了处理资源毒素的努力度与收获资源的努力度的一种最优分配方案，同时还得到次最优轨线，且此轨线最终趋近于最优解。     

污染环境中具有阶段结构的种群模型的生存分析

研究了污染环境对具有阶段结构的种群模型的影响,考虑到新生个体的出生对种群体内毒素的影响,以及死亡的种群个体将毒素带回环境。主要运用比较定理,给出了种群一致持续生存,弱持续生存和绝灭的判据。     

污染环境中具有阶段结构的种群模型的生存分析

研究了污染环境对具有阶段结构的种群模型的影响,考虑到新生个体的出生对种群体内毒素的影响,以及死亡的种群个体将毒素带回环境.主要运用比较定理,给出了种群一致持续生存,弱持续生存和绝灭的判据.     

脉冲作用对环境污染中单种群动力学行为影响

研究了一个在污染环境中的单种群模型,该模型考虑外界污染源在固定时刻排放毒素到本环境中以及在同一时刻考虑通过一些因素作用使该种群生物体排泄毒素.利用脉冲微分方程的比较定理及周期单种群Logistic模型的一些已知结论,证明了当脉冲周期小于某个阈值时,该种群灭绝,反之,则该种群持续生存.并且还证明了上述的持续生存条件也能确保该系统存在惟一的全局渐近稳定的正周期解.     

环境污染下与年龄相关模糊随机种群系统的均方散逸性

讨论了一类在环境污染下与年龄相关的模糊随机种群系统,该系统受随机和模糊两种不确定性因素的影响.在有界条件(弱于线性增长条件)和Lipschitz条件下,利用It8公式和Bellman-Gronwall-type引理,建立了均方意义下与年龄相关的模糊随机种群系统均方散逸性的判定准则.并通过数值例子对所给出的结论进行了验证.     

环境污染、内生人口增长与经济增长模型

通过把环境污染与生产总量联系起来,由消费物质多少及环境好坏、人口增长率大小这三个因素来确定效用,建立一个环境内生人口增长的经济增长模型,并按照微分方程的稳定性理论对模型进行了均衡分析和动态分析．     

Mapping QTLs on BTA6 affecting milk production traits in a Chinese Holstein population

To make marker-assisted selection (MAS) more effi-cient in improving economically important traits for farm animals, one important factor is to find markers linked to the quantitative trait loci (QTL) as closely as possible. So it is best to use the gene per se underlying the QTL. A whole genome scan for QTL is the prerequisite in the be-ginning, then mapping on some special important chro-mosomes, and then fine mapping in some target region on given chromosome aiming at gene cloning and c…     

一类污染环境下具有扩散和年龄结构的随机单种群系统分析

建立并研究了一类污染环境下具有扩散和年龄结构的随机单种群动力系统,在Hilbert空间中,通过应用It(^overo)公式证明了随机种群系统强解的存在唯一性。加入毒素对种群的影响,推广了一般的具有年龄结构和扩散的随机生物种群模型。     

历史时期湖北人口与环境

明代中叶以前，湖北人口增长缓慢，人口主要分布在岗地和丘陵地带，江汉平原的垸田开发外于健康发展阶段，人口对环境的影响是积极的、合理的，表现为地域开发的不断扩大和农田生态系统的逐步建立；明中叶之后，随着人口的快速增长，江汉平原和鄂西山地成为开发的重点，因开发时违背自然规律，人口与环境关系日见紧张与恶化。     

墨962群体主要农艺性状的遗传特征分析

对热带玉米群体墨962主要农艺性状进行了综合分析,结果表明:墨962群体遗传基础较遗传变异丰富,抗病、抗逆性强,丰产性突出.在进行群体籽粒产量改良时,百粒重的选择意义不大,而穗粗不受其他性状选择的干扰.在墨962群体的利用方面,应注重低穗位、长穗、高出籽率的选择.     

贵州苗族、水族5项群体遗传学特征的研究

对贵州苗族、水族人群共913人（苗族448人,水族465人）的叠舌、卷舌、前额发际、耳耵聍和足趾长5项群体遗传学特征进行了调查．结果显示：两民族叠舌、卷舌、前额发际和耵聍4项群体遗传学特征存在显著性差异（P〈0．05或P〈0．01）,足趾长差异不明显（P〉0．05）;两民族性别间前额发际差异极显著（P〈0．01）,苗族男女间卷舌差异明显（P〈0．01）;5项群体遗传学特征间相关性不大;贵州苗族与水族遗传距离较远．     

Response of rice cultivation to fluctuating sea level during the Mid-Holocene

Archaeological analysis of a section of ancient rice fields at Tianluoshan for diatoms, seeds and phytoliths has shown that the highest local sea level in eastern China during the Holocene appeared before 7.0 ka BP. Entering the Mid-Holocene, as seawater regressed, a vast wetland plain appeared in the coastal area, where farmers of the Neolithic Hemudu culture cultivated rice. However, there were still several sea-level fluctuations in the Mid-Holocene, of which the biggest were from 6.4 to 6.3 ka BP and from 4.6 to 2.1 ka BP. In addition, in the period dominated by wetland grass vegetation, 6.3 to 4.6 ka BP, smaller fluctuations appar- ently pushed the coastline back on to the land. Even though the sea-level rises associated with these shoreline transgressions did not have the intensity of the highest sea level period, there still would have been profound impacts on the lives and production activities of people living in the region. Archaeological evidence from ancient rice fields at Tianluoshan shows that larger sea-level rise events pushed seawater onto the land and inundated large areas of rice fields, whereas weaker sea-level rise events resulted in the intrusion of seawater along rivers, causing an increase in soil salinity and a decrease in rice yields. The impact of sea-level rise on rice cultivation caused changes in local diet. In regions where rice production fell, the prevalence of gathering and hunting rose. High sea levels in the early Holocene imply that the origin of rice cultivation in the eastern coastal plain is likely to have been in small nearby mountain basins.     

企业市场占优投资竞争策略研究

应用博弈论Cournot和Stackelberg竞争模型,并引入投资期权的分析工具研究两个竞争企业的市场占优投资决策的纯策略和混合策略.用数学模拟方法分析不同市场条件下具有或不具有垄断投资机会的企业市场占优投资决策策略,以及市场波动对不同性质企业进行市场占优投资决策的影响.结果表明,当面临激烈的市场竞争时,企业往往希望通过市场占优的投资进一步培育或发展自身的核心能力,以期望在未来的竞争中获取优势,占有更大的市场份额.但是,由于市场的不确定性,进行市场占优投资的决策可能给企业带来收益,也可能带来损失,如何进行市场占优投资的决策是企业应该切实关注的问题.     

周期环境下具有年龄结构种群动力系统的最优控制

在周期环境下,研究一类具有年龄结构种群线性动力系统的最优控制问题.利用Mazur’s定理,证明最优控制问题最优解的存在性,由法锥概念的特征刻画,得到最优控制问题最优解存在的必要条件.     

Relationship between El Nino /South Oscillation (ENSO) and population outbreaks of some lemmings and voles in Europe

Ecologists have been puzzled by population cycles of lemmings and voles for the over 70 years. At present, our understanding and explanation to this phenomenon remain controversial. Recently, El Ni?o/South Oscillation has attracted attention of ecologists on its links with population outbreaks of terrestrial animals. This paper aims to investigate the statistical relationship between outbreaks of microtine rodents and ENSO events by scanning available literature. During 1862—1894, outbreaks of Norway lemmings in Norway tended to occur in the Southern Oscillation Index (SOI) peak years or 1 year after the SOI peak years with an approximate significance level ( p = 0.057). During 1885—1931, outbreaks of voles in France tended to occur 1 year before the SOI peak years (p = 0.01). During 1946—1993, outbreaks of lemmings and voles in North Finland tended to occur 1 year before the SOI peak years with a significant level (p = 0.022); the peaks of population abundance corresponded well to the SOI trough years (equal to 1 year before the SOI peak years). Outbreaks of common voles in Poland during 1946—1975 tended to occur in the SOI peak years or 1 year before the SOI peak years (p = 0.011), and also tended to occur 1 year before the SOI peak years (p = 0.030). It was also found that the rodent outbreaks in Norway and France, rodent outbreaks in Finland and Poland synchronized well. It was suggested that the ENSO-related climate or food were key factors in causing outbreaks of microtine rodents in Europe.     

哲学视野中的人口、资源、环境的关系

人口爆炸、资源枯竭、环境恶化等一系列的发展问题 ,使人们对人与自然的关系问题感到迷惑、茫然 ,人与自然的关系越来越紧张。究其根源 ,主要是主体意识的恶性膨胀。人们在重新审视这一关系的同时 ,也极力倡导建构人与自然共生共存、共同和谐发展的新型关系。     

Cryptic evolution in a wild bird population.

Microevolution is expected to be commonplace, yet there are few thoroughly documented cases of microevolution in wild populations. In contrast, it is often observed that apparently heritable traits under strong and consistent directional selection fail to show the expected evolutionary response. One explanation proposed for this paradox is that a genetic response to selection may be masked by opposing changes in the environment. We used data from a 20-year study of collared flycatchers (Ficedula albicollis) to explore selection on, and evolution of, a heritable trait: relative body weight at fledging ('condition'). Despite consistent positive directional selection, on both the phenotypic and the additive genetic component (breeding values, estimated from an animal model) of condition, the mean phenotypic value of this trait in the population has declined, rather than increased, over time. Here we show that, despite this decline, the mean breeding value for condition has increased over time. The mismatch between response to selection at the levels of genotype and phenotype can be explained by environmental deterioration, concealing underlying evolution. This form of cryptic evolution may be common in natural environments.     

麻疯树幼苗耐旱的保护性应答

采用聚乙二醇(PEG6000)胁迫,研究了干旱胁迫条件下麻疯树幼苗叶组织中抗氧化系统的变化.结果表明:在0～60 h胁迫中,麻疯树幼苗叶片相对含水量(Rwc)明显下降;处理36 h内,丙二醛(MDA)含量略有增加,但增幅不大,叶绿素含量增加;处理36 h后,MDA含量大幅增加,叶绿素含量逐渐下降;抗坏血酸(ASA)含量...