7.0Ma以来中国黄土粉尘源区的化学风化历史研究-Sr同位素比值的证据

To investigate the changes in the chemical weathering intensity of dust source region in Asia continent, ~(87)Sr/~(86)Sr ratios of acid-washed residues from the loess deposits in China and Tajikistan were analyzed, respectively. The results and conclusions are listed as below. 1. The oscillation of ~(87)Sr/~(86)Sr ratios of acid-insoluble residues in the Chinese Loess Plateau was mainly attributed to the chemical weathering intensity of the source region and the grain size. Counteracted the effect of particle size, the calibrated 87Sr/S6Sr ratio can be used as a proxy for the chemical weathering intensity of the source region. 2. The Sr/ Sr ratios of red clay-loess sequence from the Loess Plateau indicate that the chemical weathering intensity of the dust source region between 7.0 and 2.6 Ma is stronger than that in the Quaternary period. This also suggests a general decline in chemical weathering intensity of the source region from 2.6 Ma to the present. Such pattern is more remarkable since 1.0 Ma BP. 3. The ~(87)Sr/~(86)Sr ratios of the Tajik loess during 0.8-1.8 Ma is much more higher than those from 0.8 Ma to the present. This implies that the chemical weathering intensity of the source region in Central Asia is much stronger during 0.8-1.8 Ma than the period since 0.8 Ma. 4. The record of Sr isotope ratios from both sections shows an accelerating course of aridity of the Asian dust source region over the Quaternary period.

西南天山托云盆地白垩-新生代古地磁结果及其构造意义

Western China is regarded as an assemblage of blocks or microplates. The India/Asia postcollisional kinematics of these blocks has attracted many geologists to pay attentions, especially on the geodynamics and intracontinental deformation of Tibetan and adjoining parts of central Asia. So far there are still many debates on the amount of continental shortening and extrusion within Western China blocks. Paleomagnetism plays a very important role in the paleogeographic reconstruction and depiction of kinematics of the blocks, however the unequilibrium of paleomagentic data obtained from Western China prevents paleomagnetists from studying the kinematics and intracontinental deformation on the Tibetan plateau and the central Asia. Moreover, shallower inclinations observed in the Cretaceous and Cenozoic terrestrial red sediments in central Asia makes it difficult to precisely estimate the northward convergence of Tibetan plateau and its adjacent areas since the onset of the Indian/Asian collision. In this thesis, detailed rock magnetic, chronological and paleomagnetic studies have been carried out on the Tuoyun Basin in the southwestern Tianshan to discuss the possible continental shortening and tectonic movements since the Cretaceous-Tertiary. Ar-Ar geochronological study has been conducted on the upper and lower basalt series from the Tuoyun Basin, yielding that the lower and upper basalt series were extruded during 115-113 Ma and 61.8-56.9 Ma, respectively. Both the age spectrum and inverse isochron show that the samples from the upper and lower basalt series have experienced no significant thermal events since extrusion of the baslts. Rock magnetic studies including temperature dependence of magnetization and susceptibility during a heating-cooling cycle from temperature up to 600 ℃ suggest that the baslt samples from the lower and upper basalt series are ferromagnetically predominant of magnetite and a subordinate hematite with a few sites of titanomagnetite. The predominant magnetic mineral of the intercalated red beds is magnetite and hematite. Anisotropy of magnetic susceptibility shows that both the baslts and the intercalated red beds are unlikely to have undergone significant strain due to compaction or tectonic stress since formation of the rocks. The stable characteristic remanent magnetization (ChRM) isolated from the most samples of the upper and lower basalt series and intercalated red beds, passes fold test at the 99% confidence level. Together with the geochronological results, we interpret the characteristic component as a primary magnetization acquired in the formation of rocks. Some sites from both the upper and lower basalts yielded shallower inclinations than the reference field computed from the Eurasia APW, we prefer to argue that these shallow inclinations might be related to geomagnetic secular variation, whereas the shallow inclination in the intercalated red beds is likely to be related to detrital remanent magnetization. Paleomagnetic results from the early Cretaceous-Paleogene basalts indicate that no significant N-S convergence has taken place between the Tuoyun Basin and the south margin of Siberia. Furthermore, the Cretaceous and Tertiary paleomagnetic results suggest that the Tuoyun Basin was subjected to a local clockwise rotation of 20°-30° with respect to Eurasia since the Paleocene time, which is probably subsequent to the Cenozoic northward compression of the Pamir arc.

宁夏固原寺口子剖面磁性地层与孢粉植物群初步研究

In Asia continent, several significant environmental events happened during the Cenozoic era, such as uplift of the Tibet Plateau, formation of the Asian Monsoon system, aridification of the temperate inland region in Central Asia. To investigate the history of long-term palaeoclimate evolution during the late Cenozoic, a lacustrine sequence located at Sikouzi, Guyuan county, Ningxia-Hui Autonomous Region, was studied. The Sikouzi section is about 2880 m in thickness and has a general continuous nature according to field observation. Thus this thick lacustrine record is an important archive to further understand those environmental events. In this study, detailed field measurement, layer-after-layer description and sampling, and magnetostratigraphy and palynoflora investigations are conducted at the Sikouzi section and some preliminary results have been achieved as follows. Based on Hipparion fauna, pollen data and long distinctive patterns of the local magnetozones, the confident correlation of the Sikouzi magnetostratigraphic polarity to the GPTS (CK95) is best established, indicating that the top boundary of the Sikouzi formation is dated back to -19.8 Ma B.P. and consequently no Oligocene sediments deposited locally. On the other hand, both the field observation and the correlation to GPTS indicate a nearly continuous nature for the whole sequence. The palynological results show that the grassland has been a dominant vegetation in the Sikouzi area since ~19.8 Ma B.P, although some trees/shrubs were present sparsely during the intervals of relatively warm and wet climatic conditions. This implies that the onset of the aridification in northwestern China is dated back to at least 19.8 Ma B.P. ago. The Neogene Global Climatic Optimum (-16.0 Ma B.P.) occurring between the late Early Miocene and the early Middle Miocene is well documented in the Shanwang formation, Shandong Province. However, such event was not found in the Sikouzi record, and neither in the Guide and the Hualong basins, Qinghai province. This may lead us to the conclusion that the East-Asian Summer Monsoon system remained weak during the period of the Miocene Climatic Optimum although the onset of it was traced back to the Early Oligocene. In the Sikouzi area, it was warm between the latest Miocene and the early Pliocene and then became cool in the late Pliocene. This pattern is consistent with the palaeoclimate record of the Pliocene from other areas in the world.

Borehole Optimisation System (BOS) - a case study assessing options for abstraction of urban groundwater in Nottingham, UK

The recognition that urban groundwater is a potentially valuable resource for potable and industrial uses due to growing pressures on perceived less polluted rural groundwater has led to a requirement to assess the groundwater contamination risk in urban areas from industrial contaminants such as chlorinated solvents. The development of a probabilistic risk based management tool that predicts groundwater quality at potential new urban boreholes is beneficial in determining the best sites for future resource development. The Borehole Optimisation System (BOS) is a custom Geographic Information System (GIs) application that has been developed with the objective of identifying the optimum locations for new abstraction boreholes. BOS can be applied to any aquifer subject to variable contamination risk. The system is described in more detail by Tait et al. [Tait, N.G., Davison, J.J., Whittaker, J.J., Lehame, S.A. Lerner, D.N., 2004a. Borehole Optimisation System (BOS) - a GIs based risk analysis tool for optimising the use of urban groundwater. Environmental Modelling and Software 19, 1111-1124]. This paper applies the BOS model to an urban Permo-Triassic Sandstone aquifer in the city centre of Nottingham, UK. The risk of pollution in potential new boreholes from the industrial chlorinated solvent tetrachloroethene (PCE) was assessed for this region. The risk model was validated against contaminant concentrations from 6 actual field boreholes within the study area. In these studies the model generally underestimated contaminant concentrations. A sensitivity analysis showed that the most responsive model parameters were recharge, effective porosity and contaminant degradation rate. Multiple simulations were undertaken across the study area in order to create surface maps indicating areas of low PCE concentrations, thus indicating the best locations to place new boreholes. Results indicate that northeastern, eastern and central regions have the lowest potential PCE concentrations in abstraction groundwater and therefore are the best sites for locating new boreholes. These locations coincide with aquifer areas that are confined by low permeability Mercia Mudstone deposits. Conversely southern and northwestern areas are unconfined and have shallower depth to groundwater. These areas have the highest potential PCE concentrations. These studies demonstrate the applicability of BOS as a tool for informing decision makers on the development of urban groundwater resources. (c) 2007 Elsevier Ltd. All rights reserved.

Food-web structure in low- and high-dimensional trophic niche spaces

A question central to modelling and, ultimately, managing food webs concerns the dimensionality of trophic niche space, that is, the number of independent traits relevant for determining consumer-resource links. Food-web topologies can often be interpreted by assuming resource traits to be specified by points along a line and each consumer's diet to be given by resources contained in an interval on this line. This phenomenon, called intervality, has been known for 30 years and is widely acknowledged to indicate that trophic niche space is close to one-dimensional. We show that the degrees of intervality observed in nature can be reproduced in arbitrary-dimensional trophic niche spaces, provided that the processes of evolutionary diversification and adaptation are taken into account. Contrary to expectations, intervality is least pronounced at intermediate dimensions and steadily improves towards lower- and higher-dimensional trophic niche spaces.

Estimating the Density of Honeybee Colonies across Their Natural Range to Fill the Gap in Pollinator Decline Censuses

Although pollinator declines are a global biodiversity threat, the demography of the western honeybee (Apis mellifera) has not been considered by conservationists because it is biased by the activity of beekeepers. To fill this gap in pollinator decline censuses and to provide a broad picture of the current status of honeybees across their natural range, we used microsatellite genetic markers to estimate colony densities and genetic diversity at different locations in Europe, Africa, and central Asia that had different patterns of land use. Genetic diversity and colony densities were highest in South Africa and lowest in Northern Europe and were correlated with mean annual temperature. Confounding factors not related to climate, however, are also likely to influence genetic diversity and colony densities in honeybee populations. Land use showed a significantly negative influence over genetic diversity and the density of honeybee colonies over all sampling locations. In Europe honeybees sampled in nature reserves had genetic diversity and colony densities similar to those sampled in agricultural landscapes, which suggests that the former are not wild but may have come from managed hives. Other results also support this idea: putative wild bees were rare in our European samples, and the mean estimated density of honeybee colonies on the continent closely resembled the reported mean number of managed hives. Current densities of European honeybee populations are in the same range as those found in the adverse climatic conditions of the Kalahari and Saharan deserts, which suggests that beekeeping activities do not compensate for the loss of wild colonies. Our findings highlight the importance of reconsidering the conservation status of honeybees in Europe and of regarding beekeeping not only as a profitable business for producing honey, but also as an essential component of biodiversity conservation.

Protecting peaceful protest:The OSCE/ODIHR and freedom of peaceful assembly

This article reviews ongoing work to increase awareness of, and raise standards in relation to, freedom of peaceful assembly across Europe, the South Caucasus, and Central Asia. The work is led by the Office of Democratic Institutions and Human Rights (ODIHR) at the Organisation of Security and Co-operation in Europe (OCSE). The article begins by highlighting the importance of freedom of peaceful assembly within democratic societies, and then describes the development of the ODIHR Guidelines on Peaceful Assembly. The article outlines some of the key issues of contention relating to the regulation of freedom of assembly, and discusses the process of reviewing the existing and draft legislation against the standards articulated in the Guidelines. In this context, the article also explores the potential for constructive engagement between government, civil society, and the OSCE to facilitate legislative amendments that respect key human rights norms and principles. Finally, the article reviews recent developments in training monitors of public assemblies with the aim of building local monitoring capacity and thus developing an evidence base of the practical implementation of laws relating to freedom of peaceful assembly. © The Author (2009). Published by Oxford University Press. All rights reserved.

Human height since 1820

Average height is an important indicator of people’s well-being. It is also a relatively undistorted and easy-to-measure indicator, which makes it particularly suitable for comparisons across time and space. Drawing upon an extensive body of research, the chapter describes the strengths and weaknesses of this indicator. It finds that during the 19th century, average height in Western Offshoots was much higher than elsewhere. Differences between Western Europe and the rest of the world (Eastern Europe, East Asia) were marginal, in spite of the much higher real incomes in the former region. This changed after about 1870, when people’s height began to increase in Western Europe, whereas this lagged behind elsewhere. Africans were relatively tall during much of the period studied, but experienced declining height in many countries after the 1960s. People in Southeast Asia stayed relatively short throughout the period.

Recent Developments in the Analysis of the Black Mat Layer and Cosmic Impact at 12.8ka

Recent analyses of sediment samples from "black mat" sites in South America and Europe support previous interpretations of an ET impact event that reversed the Late Glacial demise of LGM ice during the Bølling Allerød warming, resulting in a resurgence of ice termed the Younger Dryas (YD) cooling episode. The breakup or impact of a cosmic vehicle at the YD boundary coincides with the onset of a 1-kyr long interval of glacial resurgence, one of the most studied events of the Late Pleistocene. New analytical databases reveal a corpus of data indicating that the cosmic impact was a real event, most possibly a cosmic airburst from Earth's encounter with the Taurid Complex comet or unknown asteroid, an event that led to cosmic fragments exploding interhemispherically over widely dispersed areas, including the northern Andes of Venezuela and the Alps on the Italian/French frontier. While the databases in the two areas differ somewhat, the overall interpretation is that microtextural evidence in weathering rinds and in sands of associated paleosols and glaciofluvial deposits carry undeniable attributes of melted glassy carbon and Fe spherules, planar deformation features, shock-melted and contorted quartz, occasional transition and platinum metals, and brecciated and impacted minerals of diverse lithologies. In concert with other black mat localities in the Western USA, the Netherlands, coastal France, Syria, Central Asia, Peru, Argentina and Mexico, it appears that a widespread cosmic impact by an asteroid or comet is responsible for deposition of the black mat at the onset of the YD glacial event. Whether or not the impact caused a 1-kyr interval of glacial climate depends upon whether or not the Earth had multiple centuries-long episodic encounters with the Taurid Complex or asteroid remnants; impact-related changes in microclimates sustained climatic forcing sufficient to maintain positive mass balances in the reformed ice; and/or inertia in the Atlantic thermohaline circulation system persisted for 1kyr. 

Survival for oesophageal, stomach and small intestine cancers in Europe 1999-2007: Results from EUROCARE-5

Background: European regional variation in cancer survival was reported in the EUROCARE-4 study for patients diagnosed in 1995-1999. Relative survival (RS) estimates are here updated for patients diagnosed with cancer of the oesophagus, stomach and small intestine from 2000 to 2007. Trends in RS from 1999-2001 to 2005-2007 are presented to monitor and discuss improvements in patient survival in Europe. Materials and methods: EUROCARE-5 data from 29 countries (87 cancer registries) were used to investigate 1- and 5-year RS. Using registry-specific life-tables stratified by age, gender and calendar year, age-standardised 'complete analysis' RS estimates by country and region were calculated for Northern, Southern, Eastern and Central Europe, and for Ireland and United Kingdom (UK). Survival trends of patients in periods 1999-2001, 2002-2004 and 2005-2007 were investigated using the 'period' RS approach. We computed the 5-year RS conditional on surviving the first year (5-year conditional survival), as the ratio of age-standardised 5-year RS to 1-year RS. Results Oesophageal cancer 1- and 5-year RS (40% and 12%, respectively) remained poor in Europe. Patient survival was worst in Eastern (8%), Northern (11%) and Southern Europe (10%). Europe-wide, there was a 3% improvement in oesophageal cancer 5-year survival by 2005-2007, with Ireland and the UK (3%), and Central Europe (4%) showing large improvements. Europe-wide, stomach cancer 5-year RS was 25%. Ireland and UK (17%) and Eastern Europe (19%) had the poorest 5-year patient survival. Southern Europe had the best 5-year survival (30%), though only showing an improvement of 2% by 2005-2007. Small intestine cancer 5-year RS for Europe was 48%, with Central Europe having the best (54%), and Ireland and UK the poorest (37%). Five-year patient survival improvement for Europe was 8% by 2005-2007, with Central, Southern and Eastern Europe showing the greatest increases (≥9%). Conclusions Survival for these cancer sites, particularly oesophageal cancer, remains poor in Europe with wide variation. Further investigation into the wide variation, including analysis by histology and anatomical sub-site, will yield insights to better monitor and explain the improvements in survival observed over time.

Le grenadier tunisien (Punica granatum) stimule le transport de glucose dans les cellules musculaires C2C12 via la voie insulino-dépendante de l’Akt et la voie insulino-indépendante de l’AMPK

Le diabète est reconnu comme un problème majeur de santé publique causant des conséquences humaines et économiques redoutables. La phytothérapie s’offre comme une nouvelle avenue thérapeutique pour le contrôle de la glycémie. Le grenadier, Punica granatum, a servi de remède contre le diabète dans le système Unani de la médecine pratiquée en Inde et au Moyen Orient. Des études ont démontré un effet hypoglycémiant des extraits de grenadier via divers mécanismes notamment par une amélioration de la sensibilité à l’insuline et la régénération des cellules béta-pancréatiques. Cependant, aucune étude n’a démontré à ce jour, l’effet de grenadier sur le transport de glucose dans le muscle, étape cruciale dans la régulation de l’homéostasie glucidique postprandiale. De plus, l’effet de la maturation sur le potentiel antidiabétique du fruit de grenadier n’a pas été étudié. Ainsi, le but de ce projet est d’évaluer l’effet antidiabétique des extraits de grenadier sur le transport de glucose dans les cellules musculaires C2C12 en fonction de la variété et du stade de maturation du fruit et d’élucider les mécanismes d’action. Le choix des variétés du grenadier tunisien (Espagnoule [EP] et Gabsi [GB]) a été orienté pour leur pouvoir antioxydant et leur consommation locale. Deux parties de la plante ont été utilisées, les fleurs et les fruits à 3 stades de maturation soit 2, 4 et 6 mois. Les résultats ont montré que seule la variété du grenadier Gabsi stimule significativement le transport de glucose par rapport au contrôle (DMSO), et ceci sans être toxique. Cet effet est plus prononcé au stade de fruit mûr (à 6 mois) que celui de la fleur. De plus, l’extrait de fleurs stimule la voie insulino-indépendante de l’AMPK et augmente le niveau d’expression des transporteurs spécifiques de glucose (GLUT-4). Par contre, l’extrait de fruits mûrs, en plus de ces deux mécanismes, active fortement aussi la voie insulino-dépendante de l’AKT. En conclusion, cette étude présente un nouveau mécanisme d’action antidiabétique de grenadier (plus particulièrement du fruit mûr) qui est dépendant de la variété.

Studies on the mineralogy, geochemistry and origin of the modern sediments of the ashtamudy lake, Kerala

This study enfolds the environment of deposition and the lateral variation in texture, mineralogy and geochemistry of the Ashtamudy lake sediments. While the heavy mineral and clay mineral investigations enable us to decipher the nature, texture and source of sediments; organic matter and carbonate contents and the geochemical analysis of major and minor elements help establish the distribution and concentration of the same in regard to the various physico-chemical processes operating in the lake. Study of trace elements holds prime importance in this work, since their concentrations can be used to outline the extent of contaminated bottom area, as well as the source and dispersal paths of discharged_pollutants. In short, this study brings out a vivid picture of the mineralogy and geochemistry of the lake sediments in different environments, viz., the freshwater, brackish water and marine environments that are confined to the eastern, central and western parts of the lake respectively. For the better understanding and expression of the results of the analysis, the lake has been divided into 3 zones namely: eastern part, central part and western part.

La importancia de Chechenia para los intereses geopolíticos de la Federación Rusa

La importancia de Chechenia para la Federación Rusa radica en una serie de elementos históricos, religiosos, económicos. Tiene una posición privilegiada en el Cáucaso como zona de paso de recursos estratégicos provenientes del Asia Central. A nivel geopolítico tiene una importancia en el Cáucaso y sus zonas adyacentes.