哈尔滨市绿地系统生态功能分析

将哈尔滨市的典型绿地分为片状绿地和带状绿地,按乔灌草、乔草、灌草、乔木、灌木和草坪等种植结构类型,定点定时测定绿地中心和对照点的光照,温度、湿度及CO2浓度,结果表明,在片状绿地中,除草坪外,其它绿地均具有一定的遮荫效应,乔灌草、乔木、乔草和灌木结构绿地在降温、增湿和调节CO2浓度方面也均明显高于草坪,带状绿地在遮荫、降温、增温和调节CO2浓度方面也有一定的作用,其中灌木结构地遮荫效应最强,乔灌结构绿地在降温、增湿、释氧固碳方面表现最佳,相同种植结构的绿地中片状绿地的生态效益大于带状绿地,片状绿地或带状绿地的复层结构生态效益均大于单层结构。     

城市带状绿地结构类型与温湿效应的关系

利用小尺度定量测定的方法,选择北京典型的城市带状绿地--西四环旁侧4种不同内部结构以及5种不同郁闭度带状绿地(绿地宽度42 m)作为研究对象,研究带状绿地结构类型与温湿效应的关系.结果表明:与对照相比,草坪的降温增湿效应不显著,灌-草、乔-草和乔-灌-草绿地的降温增湿效果显著.当郁闭度为10%～31%时,绿地具有一定的降温增湿效应,但效应不显著;当郁闭度超过44%时,绿地降温增湿效应显著;当郁闭度超过67%时,绿地降温增湿效应显著且趋于稳定.     

北京公园绿地夏季温湿效应

选取北京典型的城市园林绿地--元大都城垣遗址公园北段不同覆盖率的乔-灌-草、乔-草型复层结构的公园绿地作为研究对象,以草坪型绿地作为对照,从水平和立体空间两个角度进行测试,研究局部绿地的覆盖率、复层结构对环境的温湿效应.结果表明:在夏季高温时段,绿地的温度随覆盖率的增加而降低,当覆盖率达到或高于60%时,其绿地才具有明显的降温增湿效果;覆盖率较高的乔-灌-草复合型绿地给环境带来的温湿度的空间影响范围较大,乔-灌-草复合型绿地的降温增湿效应好于草坪.合理的绿化结构及植物配置能使城市园林绿地较好地发挥其夏季的降温增湿效应,有利于改善城市热环境、减缓城市热岛效应.     

扬州古运河风光带不同绿地类型的降温增湿效应分析

采用LI-6400型便携式光合仪测定了扬州古运河风光带不同绿地类型气温及空气相对湿度的日变化。在夏季7：30至16：30,乔-草型和灌-草型绿地的气温均随时间推移而上升,最高值出现在12：00,但各时段的气温均低于对照点（园路）。绿地内的空气相对湿度随时间推移呈梯度下降的趋势,但绿地内的空气相对湿度明显高于对照点。研究结果表明,与对照点相比,2种绿地类型均具有明显的降温增湿效应,且乔-草型绿地的降温增湿效应优于灌-草型绿地。此外,乔-草型绿地的垂柳（Salix babylonica L．）林中,距林地中心越远,林地的降温增湿效应越弱。     

城市不同绿地结构对空气负离子水平的影响

选择佳木斯市具有代表性的绿地作为对象,对不同结构绿地的空气负离子水平进行了测定。结果表明：不同结构绿地的空气负离子水平差异极显著,以乔灌草复层结构绿地空气负离子水平最高,空气质量最佳;城市不同结构绿地空气负离子浓度大小、空气质量优劣的排序均为乔灌草结构>乔草结构>灌草结构>草坪。     

城市不同植被配置类型空气负离子效应评价

通过对南宁城区、城郊绿地及农田开发区进行负离子含量的测定,找出不同植被配置类型空气负离子效应的差别。结果表明,就空气负离子而言,城郊大规模绿地的空气质量〉农田开发区〉城区;植被配置的复层结构（乔灌草）〉简单植被配置结构（乔灌、乔草、灌草）〉单一配置结构（草坪、稀乔、稀灌草）。溪流和瀑布对增加负离子浓度的作用显著。随着海拔和郁闭度的增加,空气负离子含量有上升的趋势。空气负离子含量随季节有一定的波动。     

城市工业区园林绿地滞尘效应的研究--以武汉钢铁公司厂区绿地为例

在测定武钢工业区园林植物滞尘能力的基础上,结合绿地实地调查和武钢工业区园林绿地GIS,比较分析了园林绿地不同植物种类和层片类型的滞尘能力,并定量研究了武钢厂区园林绿地的滞尘效应.结果表明,不同园林植物的滞尘能力有较大差异,这主要与不同植物的叶表面特性、树冠结构、枝叶密集程度等差异有关.不同层片类型滞尘能力依次为落叶阔叶灌木＞常绿阔叶灌木＞绿篱＞常绿阔叶乔木＞落叶阔叶乔木＞针叶乔木＞草本.武钢厂区园林绿地的日滞尘量是9.51 t,年总滞尘量为3 089.98 t.其中常绿阔叶乔木层片年滞尘量最大,达991.68 t,落叶阔叶灌木层片最小,只有0.0181 t.由于园林绿地的滞尘量取决于所构成植物的滞尘能力及其叶面积绿量,因此,选择滞尘能力强的植物,并以乔灌草不同生活型植物进行合理配置,是提高园林绿地滞尘效应的有效途径.     

华东热湿地区四种植物群落类型对降温效应的影响研究

中国城市化进程不断推进,城市热岛效应的强度和负面影响越来越大,因此研究绿地植物群落类型对城市降温效应的影响具有重要意义。在实地调研的基础上,采用多元统计和拟合函数模型等方法,利用叶面积指数、三维绿量等因子分析4种植物群落类型的降温效应,以揭示绿地植物群落类型对降温效应影响的内在机制。夏季,4种植物群落类型对降温效应影响趋势分布排序为：乔木—灌木—草坪群落>群植小乔木群落> 乔木—草坪群落>乔木—硬质铺装群落;其中乔木—草坪群落与乔木—硬质铺装群落的降温效应较为接近。将反映植物群落特征的因子导入拟合数学方程模型,从而形成对降温效应作用较好的群落结构。研究结果和研究创新之处在于研究结果阐述了绿地植物群落类型对降温效应影响的内在作用机制。     

城市居住区绿地斑块的降温效应及影响因素分析

在夏季的高温季节对上海市 21个居住区的130个绿地斑块的环境温度和相对湿度进行了测定,比较研究了不同绿地斑块的降温效果及其影响因素.结果表明,城市绿地斑块对周围环境具有明显的降温增湿作用,能明显改善人体的舒适度,绿地中心温度降低2.6 ℃、相对湿度增加8.3%、人体舒适度增加0.8.环境温度和相对湿度对绿地斑块的降温幅度有显著影响且环境温度的影响大于相对湿度;降温幅度与环境温度呈显著正相关(R＝0.416)、与相对湿度呈显著负相关(R＝0.460);随环境温度升高、相对湿度降低,绿地中心的降温幅度最大.在影响绿地斑块降温幅度的主要结构指标中,大乔木盖度的影响力最强,其次为小乔木盖度和灌木盖度,并随盖度增加,绿地尤其是绿地中心的降温效果越来越明显.绿地类型、遮阳程度及配置不同的树种对绿地斑块的降温幅度也有显著影响;大乔木绿地的降温幅度最大(2.8 ℃),其次为小乔木绿地(2.0 ℃),乔灌相间和灌草结合的绿地平均降温幅度分别仅为1.4 ℃和1.2 ℃;以雪松[Cedrus deodara (Roxb.) G.Don]和香樟[Cinnamomum camphora (L.) Presl]为优势树种的绿地斑块降温效果最明显,草坪的降温效果最差.从降温角度考虑,居住区的绿化应多采用以乔木为主、灌草为辅的绿地结构类型,尽量避免使用单一的草地绿化类型.     

上海城市公共开放空间夏季小气候及舒适度

基于2006年5—8月上海城区5种类型公共开放空间（广场、喷泉、草坪、廊道、林地）的空气温度、相对湿度、风速和辐射强度等小气候指标,分析了各空间类型对小气候的调节作用,并采用体感气象指数（discomfort index, DI）作为评价指标,比较了各空间类型对人体舒适程度影响的差异.结果表明：上海市5种类型公共开放空间的平均温度、相对湿度等小气候因子存在一定差异;平均气温依次为广场＞草坪＞喷泉＞廊道＞林地;平均空气相对湿度依次为林地＞廊道＞喷泉＞草坪＞广场;广场面积、喷泉水体附近的风速及风向、草坪的草种类型、廊道的宽度及乔木盖度、林地的盖度及乔木林冠层高度等非气候指标分别与各自空间的气候指标呈显著相关.与其他3种空间类型相比,林地和廊道具有明显的遮荫、降温、增湿作用,对小气候的调节能力更佳.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.