环鄱阳湖区分区土地利用景观格局变化模拟研究

依据水环境约束力的大小,将环鄱阳湖区划分为核心、边缘和外围3个影响区。以该地区2005~2010年间土地利用情况为基准,通过构建CA-Markov-Logistic模型模拟2015年该地区土地利用格局情景,并采用景观格局指数进一步分析3个影响区土地利用景观格局变化趋势。研究表明:(1)从土地利用类型变化来看,覆盖环鄱阳湖区约82%土地面积的耕地和林地将有较大幅度的减少,而城建用地所占比重将大幅上升,对环鄱阳湖区的开发在逐渐加快;(2)从土地利用影响力来看,地类分布概率与人口城市化率、生活城市化率以及经济城市化率的空间分布有着一定的相关关系;(3)从模拟结果来看,环鄱阳湖区核心区耕地范围将缩小而水体范围将扩大,边缘区其他建设用地和农村居民点面积增加,外围区水体范围将大幅缩减,土地景观破碎化程度依次从边缘区-外围区-核心区的顺序下降,表明对鄱阳湖保护的作用正在显现,整个土地利用景观格局取向更为合理。     

Exposing males to female scent increases the cost of controlling <Emphasis Type="Italic">Salmonella</Emphasis> infection in wild house mice

Secondary sexual characters often provide indicators of a male’s resistance to infectious diseases to rivals and potential mates, but it is unclear why. It is often suggested that males honestly signal their health due to energetic and other physiological trade-offs between investing into secondary sexual traits vs resistance to infectious diseases. Our aim was to determine whether such a trade-off exists using wild-derived male house mice (Mus domesticus). We exposed male mice to female scent, a manipulation that induces elevations in testosterone concentration and the expression of a variety of testosterone-mediated secondary sexual traits, and tested whether this sexual stimulation impaired the males’ ability to resolve or cope with an experimental infection (Salmonella enterica). We kept the males on a controlled diet to prevent them from compensating by eating more food. We found that sexually stimulated males were able to control bacterial growth as effectively as sham-stimulated controls; however, to do so, they lost more body mass during infection compared to the controls. In contrast, we found no evidence that sexual stimulation reduced the body mass of uninfected male mice. These results indicate that males’ responses to female odor are not immunosuppressive per se, yet they increase the energetic costs of controlling infection. Our findings support the idea that there is a physiological trade-off between secondary sexual signaling vs resistance to infectious diseases and suggest that studies using only immunocompetence assays might fail to detect such energetic trade-offs. We dedicate this paper to the late Professor Chris Barnard who conducted pioneering research on this topic.     

基于元胞自动机的低影响开发对城市内涝削减效果模拟

低影响开发措施是解决城市内涝问题的重要途径。为评估其对城市内涝的防控效果,论文以福建省长汀县县城为研究案例,提出适宜在研究区开展的透水铺装、下凹式绿地、雨水罐等低影响开发措施方案,利用基于元胞自动机模型的城市内涝模型进行模拟,并通过验证发现元胞自动机模型可有效模拟城市内涝过程。对比低影响开发改造前后的内涝情况,结果显示：1）低影响开发措施能使内涝积水总量削减超过50%,暴雨重现期越长对内涝现象的削弱效果越低;2）通过分析改造前后内涝积水区的空间格局及变化特征,可见大部分内涝积水区在改造后积水削减幅度较大,卧龙山北部及汀江干流左岸的积水区内涝情况改善幅度较小;3）低影响开发改造削减效果最好的为积水深度低于0.2 m的区域,其次为积水深度高于0.5 m的区域,对积水深度处于0.2~0.5 m的区域削减效果并不明显。研究表明低影响开发措施可有效控制城市的内涝灾害。     

基于元胞自动机的复杂建筑物中人员逃生模型研究

针对复杂建筑物中人群安全疏散问题,在原有的元胞自动机行人流模型基础上,利用不同人员行进速度、不同方向行进速度的差异以及疏散连续性等特征优化该模型,使其在模拟逃生规律和疏散时间方面更加合理、可靠。通过多组人群行进速度测定试验,利用曲线拟合方法,获取不同属性人群向不同高度的台阶行进的速度,并制定台阶等级划分规则,优化人员速度计算方法,结合累积位移量,构建复杂建筑元胞自动机模型。利用Matlab软件建立原有疏散模型及复杂建筑元胞自动机模型,分别模拟某海豚表演馆疏散情况。结果表明,复杂建筑元胞自动机模型的模拟数据与实际演习数据相比,在疏散总时间方面存在5%~8%相对偏差,相比原有疏散模型,在模拟复杂建筑疏散问题中更具说服力。     

Effects of elevated yolk testosterone levels on survival, growth and immunity of male and female yellow-legged gull chicks

Androgen hormones of maternal origin contained in the eggs of avian species are considered to have positive effects on offspring characteristics and performance. However, negative consequences have also been reported, suggesting that mothers may experience a trade-off between beneficial and detrimental effects of egg androgens to offspring fitness. We studied the effects of elevated yolk testosterone (T) concentration on survival, development and phenotype of male and female yellow-legged gull (Larus michahellis) chicks by injecting egg yolks with physiological doses of the hormone. Elevated yolk T resulted in a male-biased post-hatching sex ratio, T-treated clutches producing a greater proportion of males compared to control ones at day 4 post-hatching, likely resulting from a reduction of female embryonic survival, whereas no effect of hormone treatment on hatching success or short-term chick survival was observed. In addition, T depressed post-hatching body mass in both sexes but had no effects on the intensity of the cell-mediated immune response or skeletal growth. No sex differences in egg characteristics or chick phenotype were detected. Time to hatching was not affected by T, but females originating from first laid eggs hatched earlier than males of the same laying order, independently of hormone treatment. However, the implications of sex differences in hatching times are unclear in the study species. Taken together, our results suggest that female yellow-legged gulls may be constrained in transferring androgens to their eggs by negative consequences on the viability of female offspring and growth of chicks of the two sexes.     

Immunoregulatory activity of different dietary carotenoids in male zebra finches

Summary. Many animals use carotenoid pigments to color their integument and become sexually attractive. These colorants can also serve physiological functions, protecting cells and tissues from oxidative damage as well as stimulating the immune system. Because animals often acquire several different carotenoid pigments from their diet, there is the potential for different carotenoids to exhibit different free-radical-scavenging or immunoenhancing activity. We experimentally tested how two common dietary xanthophylls - lutein and zeaxanthin - may differentially affect the immune system in male zebra finches (Taeniopygia guttata). Male T. guttata derive their red sexual beak colorants from these two carotenoids, and prior studies with this species have shown that lutein and zeaxanthin together boost cell-mediated immunity. We experimentally elevated these two dietary carotenoids separately in two groups of non-breeding zebra finches, but found that lutein-supplemented and zeaxanthin-supplemented males mounted similar cell-mediated immune responses (to phytohaemagglutinin, or PHA). Although zeaxanthin is a more conjugated carotenoid than lutein and has the potential to be a more potent antioxidant, our study suggests that such a subtle structural difference between these two biochemicals does not differentially affect immune performance in this songbird.     

多区蜂窝CDMA系统中的干扰及其抑制

在分析多区蜂窝ＣＤＭＡ系统干扰的基础上,提出了开,闭环结合的功控方式,要求和以载干比（ＣＩＲ）为基础的功控算法,从而抑制干扰,改善系统性能,增加系统容量。     

氯化汞、氯化甲基汞对大鼠肾近曲小管细胞损伤机理的研究

研究了HgCl₂和CH₃HgCl对大鼠游离肾近曲小管细胞的毒性作用及其机理.结果显示,HgCl₂和CH₃HgCl均对肾细胞有明显毒性,表现为细胞内乳酸脱氢酶（LDH）和溶酶体β-葡糖苷酸酶（β-GD）漏出增加,还原型谷胱甘肽（GSH）和蛋白巯基（PSH）含量降低,同时GSH和PSH含量的降低与LDH及β-GD漏出之间呈良好的相关关系.未观察到CH₃HgCl明显诱发肾细胞脂质过氧化作用,HgCl₂仅在50μmol/L以上才出现轻度脂质过氧化效应.     

氯化汞、氯化甲基汞对大鼠肾近曲小管细胞损伤机理的研究

研究了HgCl_2和CH_3HgCl对大鼠游离肾近曲小管细胞的毒性作用及其机理.结果显示,HgCl_2和CH_3HgCl均对肾细胞有明显毒性,表现为细胞内乳酸脱氢酶(LDH)和溶酶体β-葡糖苷酸酶(β-GD)漏出增加,还原型谷胱甘肽(GSH)和蛋白巯基(PSH)含量降低,同时GSH和PSH含量的降低与LDH及β-GD漏出之间呈良好的相关关系.未观察到CH_3HgCl明显诱发肾细胞脂质过氧化作用,HgCl_2仅在50μmol/L以上才出现轻度脂质过氧化效应.