The Younger Dryas and millenial-scale oceanographic variability in the Sulu Sea, tropical western Pacific

EXTRACT (SEE PDF FOR FULL ABSTRACT): A high resolution, AMS carbon-14-dated sediment record from the Sulu Sea clearly indicates the Younger Dryas climatic event affected the western equatorial Pacific. Presence of the Younger Dryas in the tropical western Pacific indicates this climatic event is not restricted to the North Atlantic nor to high latitudes, but is global in extent.

Paleorecords of interdecadal variability from mid-latitude varved sediments and tropical corals of the eastern Pacific [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Reconstruction of proxy variables from massive corals and varved sediments of the eastern Pacific allow us to compare variability in the ocean climate from equatorial and mid-latitude sites for a significantly longer period than is available from the instrumental record.

Oceanographic variability at Clipperton Atoll since the 1880s: stable isotopic evidence from massive corals [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Clipperton Atoll (10°18'N, 109°13'W), lies within the eastern Pacific elongated warm water pool centered at 10°N and is situated at the boundary of the North Equatorial Counter-Current (NECC) and westward-flowing eddy currents moving away from Central America. ... Fifteen coral cores were collected from massive heads of Porites lobata in April 1994 for the purpose of reconstructing oceanographic and climatic conditions at this open ocean site in the eastern Pacific.

Apparent abundance of yellowfin and bigeye tuna in the inshore, off shore and near oceanic ranges around Ceylon

Sri Lanka entered oceanic longline fishery in 1967 and have limited the areas of operation to the central equatorial belt, thus limiting their fishery to the yellowfin and bigeye tunas. Sri Lanka while developing her coastal fishery took a leap into oceanic longlining and in view of her programme for accelerated development of the fishing industry, has to fill the gap between the two fisheries by exploiting the intermediate range (off shore and near oceanic) which would chiefly be for tunas and sharks. The present paper has been prepared in this context, utilizing available data and information on the tuna longline fishery in the inshore (approximately 6-15 miles), off shore (approximately 15-100 miles) and near oceanic (approximately 100-300 miles) ranges (Fig, 1).

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 4. List of reptilia and amphibia collected in the mountains of south-west Ceylon, with notes on finding localities

Sri Lanka is a comparatively small island (65.584 km²) within the equatorial belt of calms. There are only slight seasonal variations in temperature, air humidity and day length. A description is given of the amphibian and reptile material brought back from the Austrian Indo-Pacific expedition, 1970-71. Some notes on the habitat of the animals are included.

An experimental semi-active anti-roll system

The use of anti-roll bars to provide additional roll stiffness and therefore to reduce the trade-off between ride and rollover performance has previously been studied. However, little work has been carried out to investigate the benefits of a switchable roll stiffness. Such a semi-active anti-roll system has the ability to have a low roll stiffness during straight-ahead driving for improved ride performance and high roll stiffness during cornering for improved roll performance. Modelling of such a system is conducted and the model is validated against a semi-active anti-roll system fitted to an experimental vehicle. Experimental and theoretical investigations are used to investigate the performance of such a system with several different strategies employed to switch to the high-stiffness state. The use of an air suspension on the vehicle to roll into corners is also investigated, as is the possibility of exploiting the road layout by allowing the vehicle to be in a low-roll-stiffness configuration during a corner, and then to switch to the high-roll-stiffness configuration midcorner, hence 'locking in' a roll angle. The best rollover performance improvement that was achieved was 12.5 per cent. © IMechE 2008.

抗人体艾滋病毒的核糖体失活蛋白

核糖体失活蛋白是一类作用于真核细胞核糖体, 抑制蛋白质合成的毒蛋白。近年来, 发现核糖体失活蛋白能抑制急性感染的T细胞和慢性感染的单核巨噬细胞中HIV的复制和增殖, 其作用方式独特, 不产生耐药性。至少已知8种核糖体失活蛋白有抗HIV的作用。这些核糖体失活蛋白的序列有一定的同源性。

Vibration of a high-altitude tethered balloon with application to climate engineering

A balloon tethered at an altitude of 20 km could deliver a particulate cloud leading to global cooling. Tethering a balloon at this altitude poses significant problems with respect to vibration and stability, especially in regions of high wind. No-one has ever proposed, yet alone launched, a balloon at an altitude of 20 km tethered to the ground. Owing to wind, the tether needs to be 23 km in length and is to be fixed to a ship at sea or on land in equatorial regions. Whilst the balloon at 20 km is subject to relatively modest wind conditions, at jet stream altitudes (10km) the tether will experience much higher wind loadings, not only because of the high wind speeds of up to 300 km / hr but also because of the high air density. A tether of circular cross section in these high winds will be subject to horizontal and downward drag forces that would bring the aerostat down. For this reason it is advantageous to consider a self-aligning tether of an aerodynamic cross section whereby it is possible to reduce the drag substantially. One disadvantage of a non-circular tether is the possibility of flutter and galloping instabilities. It is reasonably straightforward to model these phenomena for short lengths of aerofoil, but the situation becomes more complex for a 20 km tensioned tether with large deflection and curvature, variable wind speed, variable air density and variable tension. Analysis using models of infinite length are used to establish the stability at a local scale where the tension, aerodynamic and geometric properties are considered constant. Dispersion curve analysis is useful here. But for dynamics on a long-wavelength scale (several km) then a full non-linear analysis is required. This non-linear model can be used to establish the local values of tension appropriate for the dispersion analysis. This keynote presentation will give some insight into these issues.

Redescription of Difflugia tuberspinifera Hu, Shen, Gu et Gong, 1997 (Protozoa : Rhizopoda : Arcellinida : Difflugiidae) from China

The freshwater testate amoeba Difflugia tuberspinifera Hu et al. 1997 collected from pond and lake in China, is investigated by light and scanning electron microscopy. This little known taxon is redescribed and its morphology, biometry and ecology are supplied. After carefully comparison with other six similar species including Difflugia bartosi Stepanek, D. corona Wallich, D. corona cashi Deflandre, D. corona tuberculata Vucetich, D. muriformis Gauthier-Lievre et Thomas and Netzelia tuberculata (Wallich) Netzal we believe that the sub-spherical to spherical shell, the mulberry-shaped appearance, the 7-10 apertural tooth-like structures, the short collar and the conical spines numbering from 4 to 8 at the upper equatorial region in D. tuberspinifera set it apart from other species. Besides, statistical analysis indicates that D. tuberspinifera is a size-monomorphic species characterized by a main-size class and a small size range and the shell height is significant correlated with other morphometric characters at p < 0.05 excepting the number of aperture tooth-like structures and the number of spines. Moreover, D. tuberspinifera inhabits not only lotic but also lentic environment.

Recent progresses of silicon-based optoelectronic devices for application in fiber communication

Si-based optoelectronic devices, including stimulated emission from Si diode, 1.3 and 1.5mum SiGe photodetector with quantum structures, 1GHz MOS optical modulator, SOI optical switch matrix and wavelength tunable filter are reviewed in the paper.

不同施肥制度下潮棕壤钾素肥力演变

1990～2004年在下辽河平原进行的长期定位试验，对不同施肥制度下作物（玉米、大豆）产量及潮棕壤钾素收支和肥力变化进行了研究；同时用两种不同的方法研究了作物（玉米和大豆）的土壤缺钾临界值。 研究结果表明，不同处理对土壤K素收支状况产生不同的影响：N肥或NP肥并用加剧了土壤K的收支赤字；保持系统中养分的循环再利用，可以缓解但不能从根本上消除土壤K素的收支赤字，只有在K素循环回田的基础上配施K化肥能保持系统内部K素平衡。 未施K肥的各处理土壤速效钾和缓效K浓度均有明显的下降，其中NP和N处理土壤缓效K浓度下降幅度最大；施NPK肥的处理，土壤速效钾和缓效K浓度有所提高；K肥配合循环猪圈肥的施用，能明显提高土壤速效钾和缓效钾浓度。 根据历年试验结果进行统计，用十字交叉法得出玉米的土壤速效K临界值为78mg∙kg-1，大豆的土壤速效K临界值为74mg∙kg-1。将土壤速效K与作物相对产量进行相关分析，根据回归方程计算，玉米和大豆土壤速效K的临界值分别为82.59mg∙kg-1、81.56mg∙kg-1。 K肥对玉米和大豆的增产有一定的效果；施加循环猪圈肥的处理也能在一定程度上提高作物产量，且循环猪圈肥有稳产的作用；化学钾肥配合循环猪圈肥能显著提高玉米和大豆的籽实产量（p<0.01）。

能同时高对映选择性还原酮和亚胺的有机小分子催化体系的设计与合成

不对称催化还原反应是当今有机化学研究中最具活力的研究方向之一。在这一研究领域中，已有不少催化剂体系能够对前手性酮或亚胺进行高对映选择性还原，但极少能够对酮和亚胺同时具有很好的催化效果。本论文从光学纯的哌啶酸出发，设计与合成了一系列结构简单、合成方便的手性有机小分子路易斯碱催化剂，并研究了该系列催化剂在酮和亚胺不对称还原本课题组前期研究中开发出L-哌啶酸和（1S,2R）-1,2-二苯基氨基乙醇衍生的路易斯碱催化剂，在三氯氢硅对亚胺的还原反应中显示出很高的催化活性和对映选择性，但对酮的还原却没有得到很理想的催化效果。本研究对该催化剂进行一定的结构改造和修饰，获得了能够同时高对映选择性催化还原酮和亚胺两类底物的有机小分子催化剂。通过优化条件，取得了很好的收率（高达99%）和对映选择性（高达93%的ee 值）。而且，其底物普适性也是前所未有的，对芳香酮和脂肪酮，芳香亚胺和脂肪亚胺都具有很好的催化效果。通过机理方面的探讨，我们推测该催化体系对酮的还原和对亚胺的还原反应可能分别采用了七配位和六配位过渡态模型。Asymmetric reduction is one of the most active research areas in modernasymmetric synthesis. A number of highly efficient methods have been developed forthe asymmetric reduction of either ketones or ketimines. However, there have beenextremely rare examples of catalytic systems that allow for highly enantioselectivereductions of both ketones and ketimines.In this study, starting from optically pure pipecolinic acid, we designed andsynthesized a series of structurally simple and easily accessible chiral organic Lewisbasic catalysts and employed them in asymmetric reduction of ketones and ketimines.Previously our group has developed a highly enantioselective Lewis basiccatalyst for the asymmetric reduction of ketimines by trichlorosilane starting fromL-piperdine-2-carboxylic acid and (1R,2S)-2-amino-1,2-diphenylethanol. But thiscatalyst was found not to be very effective in the asymmetric reduction of ketones.Slight modifications of this catalyst has led to a new highly enantioselective catalystapplicable for the reduction of both ketones and ketimines by trichlorosilane. Underthe optimal conditions, this catalyst afforded excellent yields (up to 99%) andenantioselectivities (up to 93% ee). Moreover, an unprecedented substrate spectrumwas observed with this catalyst, which are highly effective for aromatic and aliphaticketones as well as aromatic and aliphatic ketimines. A heptacoordinate silicontransition structure and a hexacoordinate one were proposed for the reduction of ketones and ketimines, respectively.

N-烷基氮杂糖及其衍生物的合成

多羟基哌啶类化合物通常称为氮杂糖，由于与糖结构的相似性，亚胺基环醇表现出强的糖苷酶和糖基转移酶抑制活性，可调控在生物识别及酶结构控制中起到重要作用的糖蛋白的生物合成与水解。因此这类抑制剂有望成为与糖代谢紊乱有关的疾病的治疗药物，如：抗糖尿病、抗肿瘤、抗溶酶体贮积症及抗病毒感染（包括艾滋病）等药物。正是由于氮杂糖的重要生物活性及诱人的药用开发前景，近年来，有关氮杂糖及其衍生物的合成、生物活性及应用研究备受关注。 本论文探索了一系列的作为潜在的迈克加成中间体1-C-乙酰甲基/甲氧羰基甲基-5-N-取代呋喃核糖碳苷衍生物在碱的作用下先发生β-消除反应，接着发生分子内的迈克加成反应生成1-C-乙酰甲基-N-取代氮杂吡喃糖碳苷衍生物及1-C-甲氧羰基甲基-N-取代氮杂吡喃糖碳苷衍生物的方法，该转变过程为先通过β-消除得到非环状的α/β不饱和共轭酮或酯的中间体，接着5-N-取代氨基与分子内的α/β不饱和共轭酮或酯发生分子内的1,4-亲核加成，其中，2'-酯的环加成立体选择性的得到β型1-C-乙酰甲基-N-取代氮杂吡喃糖碳苷衍生物，而2'-酮的环加成得到立体异构体1-C-乙酰甲基-N-取代氮杂吡喃糖碳苷衍生物。此外，该类N-取代氮杂吡喃糖碳苷衍生物进一步脱除保护基，得到了一系列新的N-取代氮杂吡喃糖衍生物，拓展了氮杂吡喃糖碳苷分子库。 中间体1-C-(2'-oxoalkyl)-5-N-alkylated glycoribofuranoside的合成是由核糖为原料，通过对其结构修饰，在C-5氮原子上先引入不同的取代基，在C-1上引入乙酰甲基或甲氧羰基甲基。C-5取代氨基的引入通过两种方法：(a) 5-取代链状脂肪氨基可由链状的伯胺直接与5-甲磺酰基发生SN2亲核取代得到；(b) 5-取代芳香氨基可通过芳香醛与C-5氨基缩合再由硼氢化钠还原得到。2'-酰基的引入通过烯丙基氧化得到：2'-酮羰基由醋酸汞和琼斯试剂氧化得到；2'-酯基由高锰酸钾氧化再碘甲烷的作用下得到。 The polyhydroxylated piperidines, commonly be called azasugars. Iminocyclitols and their derivatives have exhibited remarkable biological activity to inhibit glycosidase-processing enzymes, with resulting potential chemotherapeutic applications against diabetes, cancer, lysosomal storage disorders and viral infections including AIDS. Recently, because of the important biological activity and excellent foreground on pharmaceutical application, great attention has been attracted to the synthesis of the new derivatives and analogues. In this dissertation, 1-C-(2'-oxoalkyl)-5-N-substituted-glycoribofuranosides, which used as latent substrates for intramolecular hetero-Michael addition, were converted to 2-ester and 2-ketone aza-C-glycopyranosides by base treatment. The transformation was achieved through β-elimination to an acyclic α/β-conjugated ketone or ester, followed by an intramolecular hetero-Michael addition by the 5-N-alkylated amino group. The 2-ester cycloaddition was highly stereoselective in favor of an equatorial 1-C-substitution while the 2-ketone cycloaddition was produced a pair of stereoisomers of 2′-ketonyl aza-C-glycoside. Additionally, the resultant different N-alkylated aza-C-glycopyranosides could be further prepared for various azasugar library constructions by removal of protecting groups. Synthesis of the key intermediate 1-C-(2'-oxoalkyl)-5-N-alkylated glycoribo- furanoside involved the introduction of 5-substituted amino and 1-C-2′-oxoalkyl groups from D-ribose. The 5-alkylated amino was introduced through two methods: (a) the 5-aliphatic series amino synthesized by the nucleophilic substitution of 5-mesylate using neat ethylamine, propylamine, butylamine, and hexylamine, (b) the 5-aromatic series amino synthesized by various aromatic aldehydes with C-5 amino under NaBH4 reduction. The 1-C-2′-oxoalkyl groups were introduced through oxidation of the ally group: the 1-C-allyl group was oxidized with Hg(OAc)2 and Jones reagent to the 2-ketonyl C-glycoside; the 1-C-allyl group was oxidized with KMnO4 and CH3I/NaHCO3 to 1-C-methyl acetate glycoside.

中国蔷薇属芹叶组（Rosa Sect. Pimpinellifoliae DC. ex Ser.）的分类学研究

本研究通过我国CDBI、 KUN、PE、SZ等主要标本馆约3, 500份馆藏标本的研究和野外考察相结合，对我国蔷薇属（Rosa L.）芹叶组(Sect. pimpinellifoliae DC. ex Ser.）植物以及相关组的一些种进行了性状特征、形态和微形态的研究，对该组的一些种的形态特征描述进行了补充，同时给出详细的地理和海拔范围分布图。综合花粉以及种子（瘦果）形态的研究结果重新制订了分种检索表，同时，对该组一些形态相近容易混淆的种进行了对比研究，特别对一直存在争议的绢毛复合体（绢毛蔷薇R. sericea Lindl.和峨眉蔷薇R. omeiensis Rolfe）进行了大量宏观形态特征的研究，并用光学显微镜（LM）和扫描电镜(SEM)对二者的花粉及种子形态、微形态进行对比研究和分析，主要研究内容包括： 1. 芹叶组孢粉研究 对芹叶组的10个种及相关的4个组共17个种（18个样品）的植物花粉进行了光镜和扫描电镜观察和比较研究。研究结果表明：蔷薇属植物花粉粒大小为中等偏小，极轴长23.98[21.82(R. graciliflora Rehd. et Wils.)～29.18(R. tsinglingensis Pax. et Hoffm.)] μm，赤道轴长28.65[24.15（R. graciliflora）～34.70(R. davidii Crép.)] μm；花粉属辐射对称等极单花粉，花粉形态赤道面观呈球形到超长球形；极面观为三裂圆形或近圆形,三孔沟，孔缘加厚,具中部突起的桥状盖。花粉外壁纹饰为条纹状，光镜下形态特征相差不大；在电镜下外壁条纹和脊沟内穿孔的形状、大小和频度等特征，常具组至种水平上的可见变异，可作为组至种水平划分的依据。 根据花粉外壁条纹特征及穿孔形状和数目等特征，本研究将这些植物的花粉归为5个类型，并编制了分组检索表。同时，根据条纹状的清晰度，排列方式、条纹形状、穿孔大小及其频度等方面的差异，各有特点，对该组的10个种编制了分种检索表。 2. 芹叶组种子形态研究 应用光学显微镜和扫描电镜对我国蔷薇属芹叶组14个种及相关组5个组共36种植物的种子宏观形态及种皮微形态特征进行了观察研究。结果显示，蔷薇属种子形态多样,形状分别为肾形、卵形或锥形等；种子颜色以淡棕色、褐色以及土黄色为主；种子大小种间相差悬殊，相对体积为（长×宽×厚）36.66（4.79～114.47) mm3。光镜下，种子宏观形态特征具组内一致性，在扫描电镜下种子表面结构特征因种而异，其纹饰以网纹为主，可分为3种类型，即近平滑型、负网纹型和网纹型。研究结果表明，蔷薇属种子表面纹饰与地理分布关系不大,具有组及种内稳定性。其种子形态、大小、表而纹饰类型等特征可作为蔷薇属组及种水平上的分类依据。 结合蔷薇属花粉形态研究结果，得出蔷薇属种皮微形态特征与花粉外壁纹饰特征相吻合，在代表组及种的特征上具相关性的结论。同时根据种子形态、微形态结构特征的组间区别和种间差异编制了分组及芹叶组14个种的分种检索表。 3. 绢毛蔷薇复合体的研究 通过对大量标本的研究、野外观察以及扫描电镜对绢毛蔷薇复合体的花粉形态和种皮表面结构进行研究，通过对小叶、花粉及种子的形态定量分析结果支持Rowley (1959)的观点，将峨眉蔷薇处理为绢毛蔷薇的一个变种。 综上研究结果得出，蔷薇属植物的小叶片数目、花被基数以及花粉及种子形态等性状是较为稳定的，这些特征可很好的作为分类学依据。 The morphology, pollen exine sculpture and seed coat structure of the species of Rosa sect. Pimpinellifoliae and related sections were studied.About 3,500 herbarium specimens at CDBI, KUN, PE, and SZ were examined. Field work in Sichuan and Yunnan were conducted. Revisions of some species were carried out and a new key to species of sect. Pimpinellifoliae was proposed based on morphology, pollen exine sculpture and seed coat structure, Detailed morphological descriptions, geographical distributions and the altitudinal ranges of some taxa are given. The systematics of the species complex, the Rosa sericea complex (R. sericea Lindl. & R. omeiensis Rolfe), was emphasized. This thesis focused on the following three aspects: 1. Pollen morphology of Rosa sect. Pimpinellifoliae The pollen morphology of 18 samples representing 10 species of the Eurasian Rosa sect. Pimpinellifoliae and 7 additional species of related sections was investigated under LM and SEM. The pollen grains are monadic, actinomorphic, equipolar, medium-sized, spheroidal to perprolate in equatorial view, 3-lobed circular or semi-circular in polar view, crassimarginate, pontoperculate, and with striate exine sculpture. The striate sculpture varies among sections and species. The equatorial axis ranges from 17.97 μm (R. sikangensis) to 29.18 μm (R. tsinglingensis) with an average of 23.98 μm in length, while polar axis varies from 24.15 μm (R. gracilifolra) to 34.70 μm (R. davidii) with an average of 28.65 μm in length. The pollens can be divided into five types based on striate sculpture and a key to the sections sampled was proposed accordingly. The pollen morphology of species of sect. Pimpinellifoliae is more homogeneous and different from other sections sampled and did not support the two-series subdivisions in sect. Pimpinellifoliae. A key is also provided based on characers of pollen morphology among species in sect. Pimpinellifoliae. 2. Seed coat structure of Rosa sect. Pimpinellifoliae The seed coat structure of 39 samples representing 14 species of Rosa sect. Pimpinellifoliae and 12 additional species of related sections was investigated under LE and SEM. The seed relative volume (Length × width × thickness) ranges from 4.79 to 114.47 mm3 with an average of 36.66. mm3. The seeds are reniform, ovate or oblong in shape, with orange-brown, light brown or deep brown color. Seed coat sculpture was reticulate or striate-like reticulate. There was no difference in sculpture character of various speices under LM, while three types of seed coat sculpture were identified under SEM and a key to species based on the seed coat sculpture was provided. The three types of seed coat sculpture were nearly smooth, areolate and reticulate. The study of the seed coat sculpture of same species sampled from different populations showed that characters on the seed coat are stable, and thus the size, shape and seed coat sculpture can be used in species level identification. Interestingly, characters in the seed coat sculpture and the pollen morphology in sect. Pimpinellifoliae are consistent at in specific or sectional levels. A key to the 14 species sampled was given based on seed coat sculpture. 3. The study on Rosa sericea complex The Rosa sericea complex contains R. omeiensis and R. sericea. They are morphologically similar to one another and the systematic status of R. omeiensis has been controversial. In this study we examined large numbers of herbarium specimens of R. omeiensis and R. sericea and conducted field observations in the Hengduan Mts.. We also performed SEM study of pollen morphology and seed coat structure of R. omeiensis and R. sericea. We further carried out intensive morphometric study on the leaflet, pollen, and seed morphology. Our results showed that R. omeiensis should be sunk to be a variety of R. sericea, just as Rowley’s treatment in 1959. In conclusion, the features in the number of leaflet and petal, and the morphological character on pollen and seed are relatively stable. Therefore these characters are very useful in taxon delimition.

~(12)C与~(133)Cs反应中Ba同位素的Q_(gg)产额依赖

使用47MeV/u12C离子轰击133Cs靶,由多核子转移反应产生Ba同位素。使用放射化学方法,从133Cs和反应产物中分离出产物Ba,再使用高纯Ge探测器测量Ba放射性同位素的γ活性,根据Ba同位素的活度和其他相关数据,确定Ba同位素的产生截面。通过分析测得的Ba同位素的厚靶平均产生截面,发现缺中子Ba同位素的独立截面不遵从规则的Qgg系统性。该结果可用重离子碰撞中的次级过程加以解释。