荒漠珍稀灌木半日花种群的年龄结构与生命表分析

根据对不同坡位的半日花种群的调查资料,分析了其年龄结构,编制了静态生命表,分析了存活曲线和死亡率曲线、损失度曲线,并利用生存分析理论进行了函数分析。结果表明：不同坡位的半日花种群存在下降趋势。幼龄级和老龄级个体少,中龄级个体多。不同坡位的半日花种群密度存在差异,坡上部种群密度最大,坡下部最小,坡中部居中。不同坡位半日花种群在Ⅰ龄级时期望寿命达到最大,并在Ⅶ、Ⅷ龄级时期望寿命出现波动;不同坡位的半日花种群的存活曲线整体上趋于Deevy Ⅱ～Ⅲ型之间;在第Ⅵ~Ⅷ龄级半日花种群死亡率较高,且坡中部和坡下部种群死亡率峰值比坡上部种群滞后一个龄级。生存分析引入生命表中的4个函数能较好地说明不同坡位半日花种群的结构和动态变化。     

小麦和彭梯卡偃麦草杂种及其衍生后代的细胞遗传学研究：Ⅰ.彭梯卡…

花粉母细胞中期Ⅰ染色体配对观察发现,长穗偃麦草平均染色体配对构型为：２７．６５Ⅱ（２０－３５）＋１．１５Ⅲ（０－４）＋１．２２Ⅳ（０－４）＋０．４２Ⅴ（０－２）＋０．４３Ⅵ（０－２）＋０．２０Ⅶ（０－１）＋０．０６Ⅷ（０－１）＋０．０２Ⅸ（０－１）＋０．７５Ⅰ（０－５）。大量多价体的出现说明在Ｔｋ．ｐｏｎｔｉｃｕｍ中必然存在着染色体组重复。小麦和长穗偃麦草杂种Ｆ１根尖细胞及花粉母细胞染色体醋酸洋红     

大鼠颈段脊髓灰质板层及其细胞构筑

取12只SD(Sprague-Dawley)大鼠颈段脊髓横断面冰冻切片,用焦油紫和Pal-Weigert染色法染色,光镜观察SD大鼠颈段脊髓的组织结构,对SD大鼠脊髓灰质板层的细胞构筑进行研究。结果显示,Ⅰ层边界呈长弧形,Ⅰ、Ⅱ、Ⅲ、Ⅳ层呈层叠状排列,细胞多为椭圆形。Ⅴ、Ⅵ层均可分为内侧部和外侧部,外侧部分布大型细胞,Ⅴ层内侧部以中型椭圆形、三角形细胞为主,Ⅵ层内侧部以中型梭形细胞为主。Ⅶ层位于中间带,C5-C7Ⅶ层向前角延伸和Ⅷ层一起占据前角大部,Ⅶ及Ⅷ层的中型和大型细胞呈集中分布。Ⅷ层在C1-C4及C8占前角大部,在C5-C7位于前角内侧部。Ⅸ层主要由含大型运动神经元的核团组成。Ⅹ层由中型梭形细胞和小型星状细胞组成。对比观察发现,SD大鼠脊髓颈段板层类似于猫的Rexed分层,但灰质轮廓、板层出现节段、板层形态及其变化等方面均有所不同。     

安徽巢县发现的人类枕骨化石和哺乳动物化石

1982年在安徽巢县银山发现的化石材料表明,该地点下部堆积的时代为早更新世,上部堆积的时代相当于北京猿人地点的1—4层或稍晚。一块人类枕骨化石出自上部堆积,代表一青年女性个体,很可能是属于早期智人的杭骨。该地点的动物群具有东洋界和古北界的色彩。     

新疆布尔津盆地晚始新世一早渐新世岩石及生物地层

布尔津盆地中的第三纪地层过去被称为“乌伦古河组”。该套地层的岩性组合独特 ,不同于乌伦古河流域该组命名剖面的乌伦古河组。依据布尔津县城西北 2 0km处的额尔齐斯河北岸出露的地层剖面 ,建立两个岩石地层单位 :下部额尔齐斯河组和上部克孜勒托尕依组。额尔齐斯河组为一套富含铁质的色彩鲜艳的碎屑堆积 ,克孜勒托尕依组是一套浅黄绿色砂岩夹杂色泥岩地层。克孜勒托尕依村附近的建组剖面为一连续沉积剖面 ,含有 3个确切的哺乳动物化石层位、5个化石地点。最下部化石层含有典型的始新世Ergilian期哺乳动物 ,其余两个层位的化石均属早渐新世Shandgolian期哺乳动物。因此 ,该剖面为一Ergilian Shandgolian(晚始新世—早渐新世 )过渡时期的地层剖面 ,是进一步研究该过渡期哺乳动物群替代及Ergilian/Shandgolian地层界线的理想剖面。     

秦岭核桃坝石炭纪牙形石及其生物相

陕西凤县核桃坝剖面下部以细、粉砂岩和碳酸盐岩为主,上部以重力流沉积的砂岩、砾岩为主。根据牙形石组合,剖面１－３层为下石炭统杜内阶,与镇安地区界河街组下部相当;４－８层为上石炭统维斯发阶,与华北本溪组可能相当,剖面第３和４层之间可能由于构造关系缺失或未出露相当韦宪至纳缪尔阶的大部分地层。根据牙形石生物相、沉积相和遗迹化石特征,石炭纪时这一地区为一较广阔和海盆,由于受构造控制,盆地向北加深,总体呈楔形     

广西来宾蓬莱滩二叠纪牙形刺与吴家坪阶（乐平统）的底界

蓬莱滩剖面的牙形刺最早是由Ｍｅｉｅｔａｌ．（１９９４ｃ）研究的。本文重点讨论了蓬莱滩剖面吴家坪阶和茅口阶界线层的牙形刺,对有关牙形刺种的时限、分带及层位提出了一些不同的看法。本文着重指出,吴家坪阶的底界在茅口组的最上部,即在１８层上部２ｍ厚的浅水相灰岩内部通过,至少比１８层顶低０．５５ｍ,不应把吴家坪阶底界划在１８层与１７层之间,它比事件地层界线稍高,与吴家坪组和茅口组的界线并不一致。所谓“最佳自然界线”的概念,在蓬莱滩剖面并不能得到证实。Ｊｉｎｏｇｏｎｄｏｌｅｌａ和Ｐｓｅｕｄｏｃｌａｒｋｉｎａ属名无效。     

内蒙古额济纳旗发现的一种泥盆纪菊石

1977和1978年,宁夏地质局综合研究队和西安地质矿产研究所部分同志,在内蒙古自治区西部巴丹吉林沙漠北缘的珠斯楞海尔罕一带,调查古生代地层时,在珠斯楞海尔罕峰之北西五公里的Ⅷ-Ⅷ'剖面的珠斯楞组底部,采得数枚菊石标本,经笔者鉴定为Anarcestes (Anarcestes) praecursor Frech。Ⅷ—Ⅷ'剖面珠斯楞组下部的岩性如下: 珠斯楞组(下部) 3.灰色薄层粗粒含绢云母钙质砂岩夹薄层细砾岩,产牙形刺Pandorinella steinhornensis cf.steinhornensis Ziegler,及腕足类、三叶虫、腹足类和双壳类等化石 12米 2.灰色中薄层含绢云母钙质粗砂岩与细砾岩互层,产菊石.Anarcestes(Anarcestes)Praecursor Frech,及鹦鹉螺类、腕足类、三叶虫、腹足类、双壳类、苔藓虫和鱼类碎片 8米 1.灰色厚层砾岩,灰岩砾石中含志留纪四射珊瑚     

中国浙江长兴县煤山二叠—三叠系界线：三叠系底界的全球界线…

浙江长兴煤山剖面的二叠－三叠系界线层为连续的浮游相沉积没有任何间断,侧向上也是连续的。煤山是长兴阶的层型剖面所在地,长兴阶的上部,界线层和三叠系的下部,每一层都发现有牙形刺,可以逐层追索牙形刺的演化关系。煤山剖面几乎没有任何热力变质（ＣＡＩ＝１－１．５）。煤山剖面的菊石、牙形刺、双壳类、腕足类等多门类化石以及有关事件已得到了很好的研究。绝对年龄和古地磁也已得到深入研究。孢子的存在和易于识别的事件能     

三峡库区二级阶地发现的东方剑齿象化石及其环境与考古学意义

本文记述的象化石产自三峡库区长江右岸二级阶地。该二级阶地沉积物可分为两个沉积单元:由下部含化石的砂砾层和上部具乌木的土状堆积组成。显然,这些沉积物反映不同的古环境。据铀系法测定,下部沉积的年代约为距今6.4万年前,而上部堆积层的14C测年值为距今约8 000年。依二级阶地上、下层间呈不整合接触和测年数据,下部沉积之后曾有较长时间的沉积间断。下部埋藏阶地的砂砾石层被钙质胶结的现象表明,该地区在二级阶地形成后有一段气候干燥而寒冷的时期。迄今三峡库区已发现了55处旧石器地点,大多数位于二级阶地中,但缺乏化石和测年的可靠证据。这次埋藏阶地象化石的发现为三峡地区二级阶地的旧石器遗址提供了可资对比的地层和时代依据,对古人类在该地区生存行为演变的阐释及旧石器分期提供了重要参照。     

New chronometric data from Ifri n'Ammar (Morocco) and the chronostratigraphy of the Middle Palaeolithic in the Western Maghreb

In addition to South Africa, the Northwestern corner of the African continent is providing a wealth of data for the understanding of the behaviour of early modern humans. In NW Africa, this modern behaviour is associated with a technocomplex called 'Aterian'. However, its definition as well as chronological position is heavily debated. As a common notion, the 'Aterian' is placed as the (more or less) last technocomplex of the Middle Stone Age/Middle Palaeolithic. However, the stratigraphy of the Moroccan site of Ifri n'Ammar provides evidence that the 'Aterian' cannot serve as a chronostratigraphic entity because of its presence in a stratigraphical sequence before as well as after Middle Palaeolithic industries lacking tanged tools. These should supposedly all occur beneath any layer containing tanged lithic objects, which are, at present, the main criteria for assigning an assemblage to the 'Aterian'. According to the sequence of Ifri n'Ammar, the relative chronostratigraphical position of tanged tools is therefore shown not to be a single unit. Thermoluminescence (TL) dating of heated artefacts from the main layers of Ifri n'Ammar provides a first chronostratigraphic backbone for the site and for the Maghreb. Layer 'Upper OS', which contains tanged items as well as personal ornaments is dated to 83.3 ± 5.6 ka (n = 10), while the underlying 'Lower OS', which is lacking tanged pieces, is dated to 130.0 ± 7.8 ka (n = 9). The following layer (Upper OI), which again contains tanged items, and thus provides the earliest appearance of the technique of tanging is dated to 145 ± 9 ka. The base of the sequence is formed by a Middle Palaeolithic layer (Lower OI) again lacking tanged objects and dated to 171 ± 12 ka by TL on heated lithic artefacts. These data significantly push back in time the earliest occurrence of tanged tools and the sequence calls for a complete revision of the Maghreb chronostratigraphy.     

古人类遗址湖北郧西黄龙洞的铀系年代

湖北郧西黄龙洞为近年来发现的晚期智人遗址。本文报道该地点具明确层位意义的洞穴次生碳酸盐岩和骨化石样铀系测年的结果。含文化堆积下伏一局部钙板的年代为约100ka BP, 其中部偏上一局部钙板为约77ka BP, 表层钙板形成于27—57ka BP间。人类化石和石制品出土于文化堆积的底部, 其年代应在57—100ka BP, 并很可能在77—100ka BP间。与人牙化石同层的四枚犀牛牙化石在35—72ka BP间, 与基于次生碳酸盐岩的年代框架没有冲突。本文结果为中国现代人类的早期出现和距今40—100ka BP间有人类活动提供了有力证据。     

Thermoluminescence dating tests of Pleistocene sediments from uplifted marine shorelines along the southwest coastline of the Calabrian Peninsula (southern Italy)

This paper presents TL age estimates of Pleistocene raised marine terraces from southern Calabria (southern Italy). It focuses on the dating of last interglacial shallow-marine sand deposits, including several Tyrrhenian key reference deposits whose stratigraphic assignment is based on biostratigraphic evidence (presence of a Strombus bubonius fauna) and geochronometric data (amino-acid data calibrated with U/Th dates on coral). The TL age estimates are obtained on alkali feldspar coarse grains using their blue TL emission. They are in good agreement with the IR-OSL age estimates obtained on the same feldspar samples. Our feldspar TL method is tested on two Tyrrhenian key reference sites, Ravagnese and Bovetto, in the Reggio di Calabria area. Their measured TL age estimates (97 ± 11 ka and 100 ± 10 ka) are lower than their estimated geological age (i.e. Oxygen Isotope Substage 5e). The correction for long-term fading suggested by Mejdahl (1988), is tested on these two samples using a lifetime of 446 ka as estimated from both Calabrian and Miocene sand collected within the same area. This correction would yield preliminary TL ages (116 ± 13 ka and 116 ± 12 ka) that are in better agreement with the expected geological age. The application of our TL method to paleoshorelines lying below the Tyrrhenian reference shoreline of Ravagnese-Bovetto, yields stratigraphically consistent TL age estimates. The TL method is also applied to two supposedly pre-last interglacial paleoshorelines which are geomorphologically older than the Tyrrhenian reference shorelines. They remain however chronologically undifferentiated, both by the TL and the amino-acid methods. Finally, the preliminary feldspar TL results obtained on the Miocene and the Calabrian sand deposits (> 1 Ma), suggest that our feldspar TL method is limited, in the SW Calabrian area, to about 200 ka.     

Newly recognized Pleistocene human teeth from Tabun Cave, Israel

Seven human teeth from Tabun Cave, Israel, curated at the Natural History Museum London since 1955, are of uncertain provenance and identity. They are all from the upper dentition, without duplications, and are characterized by a similar preservation. The Catalogue of Fossil Hominids (1975) suggested that they might have derived from Tabun Layer A (Bronze Age to Recent). However, one of us (AC) noted some distinctive features of these teeth that warranted further study. They are here assigned to a single individual, Tabun BC7. Their morphology and metrics were then compared with the frequency of Late Pleistocene and Early Holocene groups from Europe, North Africa and Middle East. A fragment of the right M3 crown of Tabun BC7 was removed for ESR and U-analysis, and it was determined that only samples from Layer B have similar dose values. Using the sediment dose values of layer B, preliminary age estimates of 82 +/- 14 ka (early U-uptake) and 92+/-18 ka (linear uptake) were obtained. U-series disequilibrium determined from other samples attributed to Layer B resulted in a U-uptake history close to linear uptake, giving a very comparable age estimate of 90(+30)(-16) ka. The dose value previously obtained on an enamel fragment from the Tabun C1 dentition is nearly double the value measured for BC7, and tentative age estimates for C1 were in the range of 143+/-37 ka. However, due to uncertainties in the exact provenance of the human fossils, we cannot confirm that C1 is older than the new tooth sampled here, and both C1 and BC7 can be attributed to Layer B on chronological grounds. On the basis of chronology, dental morphology and metrics, the specimen named Tabun BC7 was identified as a probable Neanderthal.     

Luminescence chronology of cave sediments at the Atapuerca paleoanthropological site, Spain

Ascertaining the timing of the peopling of Europe, after the first out-of-Africa demographic expansion at the end of the Pliocene, is of great interest to paleoanthropologists. One of the earliest direct evidences for fossil hominins in western Europe comes from an infilled karstic cave site called Gran Dolina at Atapuerca, in a stratum approximately 1.5m below the Brunhes-Matuyama (B-M) geomagnetic boundary (780ka) within lithostratigraphic unit TD6. However, most of the meters of fossil- and tool-bearing strata at Gran Dolina have been difficult to date. Therefore, we applied both thermoluminescence (TL) and infrared-stimulated-luminescence (IRSL) multi-aliquot dating methods to fine-silt fractions from sediment samples within Gran Dolina and the nearby Galería cave site. We also applied these methods to samples from the present-day surface soils on the surrounding limestone hill slopes to test the luminescence-clock-zeroing-by-daylight assumption. Within the uppermost 4m of the cave deposits at Gran Dolina, TL and paired TL and IRSL ages range stratigraphically from 198+/-19ka to 244+/-26ka. Throughout Gran Dolina, all luminescence results are stratigraphically self-consistent and, excepting results from two stratigraphic units, are consistent with prior ESR-U-series ages from progressively deeper strata. Thermoluminescence ages culminate at 960+/-120ka approximately 1m below the 780ka B-M boundary. At Galería, with one exception, TL and IRSL ages range stratigraphically downward from 185+/-26ka to 503+/-95ka at the base of the lowermost surface-inwash facies. These results indicate that TL and (sometimes) IRSL are useful dating tools for karstic inwash sediments older than ca. 100ka, and that a more accurate chronostratigraphic correlation is now possible among the main Atapuerca sites (Gran Dolina, Galería, Sima de los Huesos). Furthermore, the oldest TL age of ca. 960ka from Gran Dolina, consistent with biostratigraphic and paleomagnetic evidence, implies a probable numeric age of 900-950ka for the oldest hominin remains ( approximately 0.8m below the TL sample). This age window suggests a correspondence to Marine Isotope Stage (MIS) 25, a relatively warm and humid interglaciation.     

Structural and functional analysis of extracellular loop 4 of the Nhe1 isoform of the Na(+)/H(+) exchanger

The mammalian Na(+)/H(+) exchanger isoform 1 (NHE1) is a ubiquitously expressed plasma membrane protein. It regulates intracellular pH by removing a single intracellular H(+) in exchange for one extracellular Na(+). The membrane domain of NHE1 comprises the 500 N-terminal amino acids and is made of 12 transmembrane segments. The extracellular loops of the transmembrane segments are thought to be involved in cation coordination and inhibitor sensitivity. We have characterized the structure and function of amino acids 278-291 representing extracellular loop 4. When mutated to Cys, residues F277, F280, N282 and E284 of EL4 were sensitive to mutation and reaction with MTSET inhibiting NHE1 activity. In addition they were found to be accessible to extracellular applied MTSET. A peptide of the amino acids of EL4 was mostly unstructured suggesting that it does not provide a rigid structured link between TM VII and TM VIII. Our results suggest that EL4 makes an extension upward from TM VII to make up part of the mouth of the NHE1 protein and is involved in cation selectivity or coordination. EL4 provides a flexible link to TM VIII which may either allow movement of TM VII or allow TM VIII to not be adjacent to TM VII.     

Evolutional process and depositional cycles of Peking Man Cave in relation to the living environments and cultural development of Peking Man

Evolutional process of the Peking Man Cave, from funnel and vertical channel development in the Early Pliocene to the cave close in the late Middle Pleistocene, may be divided into six stages. Cave deposits in filling process of the cave from Layer 13 to Layer 1 can be divided into seven depositional cycles. These cycles allow a correspond with the loess sequences S7-L2 in China and oxygen isotope stages 19-6 of climatic cycles I-C of deep sea records. The living environments and cultural development of Peking Man in closely related to the cave environments of each stage in evolutional process and each cycle in depositional process of the cave are researched in this paper. The cave evolutional process has gone through about 4 Ma. The Peking Man start entered into the cave and made stone implements before 580 ka B.P. The cultural development of Peking Man may be divided into the early, middle and late three stages about in 580–420 ka, 420–340 ka and 340–250 ka, respectively. Peking Man's first used fire is about 530 ka B.P. Habitation of Peking Man concetrated in the western part of the cave after 340 ka B.P. when eastern cave roof was collapsed. Peking Man left the cave after 250 ka B.P. during the cave was continuous collapsed and almost filled up.     

Structural and functional analysis of extracellular loop 4 of the Nhe1 isoform of the Na+/H+ exchanger

The mammalian Na⁺/H⁺ exchanger isoform 1 (NHE1) is a ubiquitously expressed plasma membrane protein. It regulates intracellular pH by removing a single intracellular H⁺ in exchange for one extracellular Na⁺. The membrane domain of NHE1 comprises the 500 N-terminal amino acids and is made of 12 transmembrane segments. The extracellular loops of the transmembrane segments are thought to be involved in cation coordination and inhibitor sensitivity. We have characterized the structure and function of amino acids 278–291 representing extracellular loop 4. When mutated to Cys, residues F277, F280, N282 and E284 of EL4 were sensitive to mutation and reaction with MTSET inhibiting NHE1 activity. In addition they were found to be accessible to extracellular applied MTSET. A peptide of the amino acids of EL4 was mostly unstructured suggesting that it does not provide a rigid structured link between TM VII and TM VIII. Our results suggest that EL4 makes an extension upward from TM VII to make up part of the mouth of the NHE1 protein and is involved in cation selectivity or coordination. EL4 provides a flexible link to TM VIII which may either allow movement of TM VII or allow TM VIII to not be adjacent to TM VII.     

High-precision U-series dating of Locality 1 at Zhoukoudian, China

Thermal ionization mass spectrometric(230)Th/(234)U dating has been carried out on intercalated speleothem samples from the limestone cave occupied by Homo erectus at Zhoukoudian, China. The samples were recently collected in proper stratigraphic context after detailed field examinations. The results show that the age of the No. 5 Skull from Layer 3 is >400 ka, possibly in the range of about 400-500 ka, and that the hominid fossils from the lower strata are at least 600 ka and possibly >800 ka, much older than previously thought. The near-equilibrium(230)Th/(234)U ratios and internal consistency of the dates and stratigraphy lend credence to the results and allow us to comment on their important implications for human evolution.     

Biostratigraphy and paleoceanographic significance of Paleocene radiolarians from offshore eastern New Zealand

A 100-m-thick Paleocene sequence of mainly pelagic sediments at ODP Site 1121, on the eastern flanks of the Campbell Plateau, contains few to common radiolarians of relatively low diversity in the lower 40 m (Early to early Late Paleocene) and abundant, diverse radiolarian assemblages in the upper 60 m (mid-Late Paleocene). The 150 taxa recorded from the entire Paleocene interval are thought to under-represent the actual species diversity by at least one half as many morphotypes have not been differentiated below the level of genus. Assemblages in the lower 40 m are similar to those described from onland New Zealand and DSDP Site 208 (northern Lord Howe Rise); they are correlated with South Pacific radiolarian zones RP4 and RP5. Assemblages in the upper 60 m differ from other known Late Paleocene assemblages in the great abundance of plagiacanthids and cycladophorids. Similarities are noted with later Cenozoic cool-water assemblages. This upper interval is correlated with South Pacific zone RP6, as revised herein, based on comparison with faunas from Site 208 and Marlborough, New Zealand. The interval is also correlated with the upper part of North Atlantic zone RP6 (RP6b–c) based on the presence of Aspis velutochlamydosaurus, Plectodiscus circularis and Pterocodon poculum. Other species, such as Buryella tetradica and Buryella pentadica, are valuable for local correlation but exhibit considerable diachroneity between the Pacific, Indian and Atlantic Oceans. An age model for the Paleocene interval at Site 1121, based on well-constrained nannofossil and radiolarian datums, indicates that the rate of compacted sediment accumulation doubles from 15 to 30 mm/ka at the RP5/RP6 zonal boundary. In large part this is due to a sudden and pronounced increase in accumulation rates for all siliceous fossils; radiolarians and larger diatoms increase from <100 to >10 000 specimens/cm²/ka. This apparent increase in biosiliceous productivity is age-equivalent to a mid-Paleocene cooling event (57–59 Ma) identified from global stable isotope records that is associated with the heaviest δ¹³C values for the entire Cenozoic.