云南鹤庆盆地末次盛冰期的孢粉记录与古季风

通过研究相当于末次盛冰期鹤庆古湖泊沉积物4．6－9．0m段的孢粉记录,对该区末次盛冰期阶段的植被与古季风变迁模式进行了恢复。该区末次盛冰期冷湿的气候特点与同时东部干旱的草原植被、青藏、高原的荒漠植被和黄土高原区风尘堆积存在明显差异,而与滇池的气候记录有较好的一致性。冰期内部的气候波动与深海氧同位素记录有较好的可比性。冰期冷锋强度的增加,与北方冬季风的经常入侵和冰期青藏高原的冷源效应有关。     

末次冰期南海巽他陆架上的植被和气候——17962孔孢粉记录

提供了南海大陆坡上17962孔深海沉积物的孢粉记录.该孔长8 m,底部14C年龄为30 000 a BP,跨越了深海氧同位素3期、末次冰期、冰消期和全新世几个地质历史阶段.孢粉记录显示末次冰期低海面时南海南部出露的陆架上覆盖了低地雨林.同时,在邻近的岛屿上山地雨林扩张,表明气候比现在凉,但是没有变干的迹象.冰消期植被和气候都经历了快速变暖和变凉的波动.全新世时,红树林和低地雨林的扩张以及孢粉沉积率的明显降低均表明气候变暖,海面上升,大陆架被淹没.     

东欧黄土-古土壤剖面的孢粉和气候地层学记录及其与ESR测年的海相地层对比

记述东欧平原黄土－古土壤剖面多重年代地层的划分结果,评估黄土地区更新世主要的古地理事件的对比,建立东欧平原黄土－古土壤发育时期的17个期－9个间冰期和8个冰期,间冰期内次一级单元是吸热凉温阶（endothermal coolings)（冷时段,cold speels),干热阶,湿热阶（thermoxerotic and thermohygrotic stges)和间冰期中次级气候韵律,以及冰期内的冰阶（Stadials),间冰阶（Interstadials),中间阶（interphasials),湿冷阶（cryohygrotic),干冷阶（Cryoxerotic stages) 和冰期中的次级气候韵律,其中吸热凉温阶占据了间冰期的大部分。东欧平面黄土－古土壤形成时期的环境和植被演化由以下剖面的孢粉资料构成：上Oka(Likhvin-Chekalin section),上Don(Strelitsa Section),中Kuma(Otkaznoe,setion),中Dniester(Molodova section,Ketrosy section)和中Desna (Arapovichi section),根据孢粉－气候地层研究获得的原始资料,本文重建了欧亚大陆北部60万年以来的古气候事件,古基岩沉积,冰川,冰缘,外冰缘带沉积,并进行了周期的确定和远距离对比,在综合年代地层柱上的古环境事件及其相应的带和年代地层的对比,是依据亚化石化的软体动物外壳的电子自旋共振分析结果,已知的间冰期集中在58万年,40万年,31万年,22万年及14．5－7万年之间,这些孢粉序列,电子自旋共振测年的气候温暖事件及其他文献记载 的古环境事件的对比关系都标注在上部11个氧同位素阶段里。     

南海184站深海沉积中孢粉、藻类研究及古环境分析

对南海184站深海柱状剖面进行了孢粉、藻类研究,根据孢粉成分的变化将南海184站深海沉积从下至上划分了5个孢粉组合带,依次为:Ⅰ带(460-370 cm):Quercus(常绿)-Pinus-Dacrydium-Magnolia-Polypodiaceae孢粉带;Ⅱ带(370-250 cm):Taxodiaceae-Quercus(常绿)-Pinus-Polypodiaceae孢粉带;Ⅲ带(250-140 cm):Pinus-Polypodiaceae-Gramineae-Pteridium孢粉带;Ⅳ带(140-95 cm):Polypodiaceae-Pinus-Quercus(常绿)-Gramineae孢粉带;Ⅴ带(95-0 cm):Dacrydium-Pinus-Cyathea-Polypodiaceae孢粉带.并相应恢复了南海东部12万年以来4个植被、气候和古环境演替阶段,结合氧同位素测年资料,对184站柱状地层时代划分做了讨论,为南海古植被、古气候和古环境演变研究提供了科学依据.     

根据日本中部琵琶湖深井孢粉资料重建第四纪古植被和古气候及全球古气候对比

根据日本中部琵琶湖深井钻探资料研究了过去3Ma的古植被、地层及古气候。由湖底取得的200m和1400m样品的孢粉组合可分别划分出19个和37个带,反映了湖区及其周围自晚上新世以来的古植被和古气候演变史。在冰期阶时琵琶湖附近山区的典型植被为亚北极带,低地为冷温带。而在间冰期阶里山区一般为温带或冷温带植被,低地则主要由落叶和常绿树组成的温带和暖温带的植被。在进行过去3Ma古植被、古气候演变对比中,当地古气候史和以下资料显示出明显的一致,例如加勒比海、西太平洋及赤道海洋的氧同位素资料,地中海西部(Mallorca)的沉积旋回,欧洲中部的风成沉积序列,日本关东和新几内亚的海平面变化记录,以及在南美波哥大高地和以色列死海裂谷根据孢粉得出的古气候变化记录。     

末次冰期南海巽他陆架上的植被和气候——17962孔孢粉记录

提供了南海大陆坡上17962孔深海沉积物的孢粉记录。该孔长8m,底部^14C年龄为30000aBP,跨越了深海氧同位素3期,末次初期,冰消期和全新世几个地质历史阶段。孢偻记录显示末次冰期低海面时南海南部出露的陆架上了低地雨林。同时,在邻近的岛屿上山地雨林扩张,表明气候比较在凉,但是没有变干的迹象,冰消期植被和气候都经历了快速变暖的变凉的波动。全新世时,红树林和低地雨林的扩及孢粉沉积率的明显降低均表明气候变暖,海面上升,大陆架被淹没。     

南海北部更新世高分辨率孢粉序列与气候变化

依据南海ODP1144站下段（225.7-501.3m,ca.0.36-1.02Ma)孢粉记录,将1144站下段225.7-501.3m划分19个组合带（11-29）,并分别与氧同位素11-29期（MISs11-29)相对应。冰期时,花粉总沉积率增加,孢粉组合以松粉（Pinus),蕨类植物孢子（Fern)含量降低,草木植物花粉（Herb)含量增加为特征。气候干冷;间冰期时,则相反,间冰期孢粉组合特征反映其气候特征与现代相似,约0.82Ma后孢粉组合中的热带山地针叶类分子叶枝杉（Phyllocladus)的出现,以及草本植物禾本科（Gramineae),莎草科（Cyperaceae)取代耐干冷的蒿属（Artemisia),可能与夏季风增强有关,这一现象可与中国第四纪黄土-古土壤记录进行比较。     

再论南京直立人和北京直立人的年代与环境

以更新世全球性气候变化规律为基准,结合深海氧同位素阶段的划分,以及中国冰期与其对比关系等方面的研究进展,对以往学者所提出的一些更新世事件与氧同位素时段的对比关系进行了检验。结果佐证了南京直立人生活于昆仑主冰期,年代约为距今642ka—620ka,可能与MIS16相当的观点。研究同时表明:北京直立人可能生存于前大间冰期(MIS15—13)的初期,推测最早的北京直立人的年代为距今约620ka。     

南海北部0.36-1.02Ma高分辨率碳屑记录及天然火

依据南海ODP1144站下段（225．7－501．3m,ca.0.36-1.02Ma)碳屑、孢粉记录,将1144站下段225.7-501.3m划分19个碳屑、孢粉组合带（11－29）,并分别与氧同位素11－29期（MIS11－29）相对应。冰期时,草本植物花粉和碳屑总沉积率增加,气候干燥,天然火的强度较大;冰期MIS24,大陆内部及冰期出露的大陆架上的天然火灾强度相对最弱;而冰期MIS12,大陆内部及冰期出露的大陆架上的天然火灾强度相对最强;间冰期气候湿润,草本花粉和碳屑总沉积率降低。一方面由于间冰期海平面上升,大陆架被淹没,导致碳屑来源减少;另一方面亦反应天然火灾强度减低。间冰期MIS17,25和27碳屑沉积率分别较冰期MIS18,24及26略高,推测间冰期MIS17,25和27冬季风强度仍相对较强,大陆内部天然火灾强度亦相对较强。     

四万年来南海北部周边地区植被演替序列—孢粉生物群区化方法恢复古植被的尝试

就南海北部海域17940孔的孢粉资料,利用孢粉生物群区化方法和因子分析方法,对南海北部周边地区4万年以来的植被演替序列进行研究。结果表明：对于深海沉积物,在排除远距离搬运的花粉尤其是松属（Pinus L.)花粉的噪音后,可以利用孢粉生物群区化方法恢复周边大陆古植被演替序列。因子分析表明,湿度和温度的变化是影响南海北部周边大陆植被演化的主要因子。在40500－11100aBP南海北部沿海大陆地区的古植被,主要为常绿阔叶林（WAMF）,山地针叶林（MRGF）分布于低山、丘陵、而广泛出露的大陆架上则发育了以蒿属(Artemisia L.)为主的草原（STEP）景观：末次冰期时环境变化的突出特征山地针叶林（MRGF）、常绿阔叶林（WAMF）与草原（STEP）之间的频繁交替,反映了气候冷湿和温干的千年级尺度的迅速变化,可以与Heinrich事件以及Dansggard-Oscherge事件进行对比。其中在7.0m处（12700aBP)所恢复的山地针叶林（MRGF）景观反映了一次气候变冷变湿的事件,可能与新仙女木事件相对应。全新世早期和末期较多出现热带雨林（TRFO0以及热带季雨林（TSFO）景观,而全新世中期以常绿阔叶林（WAMF）为主,缺乏热带雨林（TRFO）以及热带季雨林（TSFO）景观,可能表明在全新世中期尽管温度升高,但湿度有可能降低。     

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.