85 resultados para Millennium Eruption


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Over the course of the past two decades there has been growing research interest in the site formation processes of shell middens. This stands along-side and is being used to inform cultural, dietary and palaeo-environmental reconstructions. Just as midden site formation processes have turned out to be many and varied, however, the kinds of shell-bearing sites that past human communities created are likely to have been no less diverse. Subsuming such sites under a single category - shell middens - normalises that variation and may lead to the misinterpretation of site function. The greater part of research in this field also continues to focus on coastal shell middens; comparatively little attention has been paid to middens containing freshwater and especially terrestrial molluscs from hinterland locations. As a result, much of the current understanding about shell-midden sites carries a spatial as well as a functional bias. This paper hopes to contribute towards discussion on both fronts. It presents a detailed examination of the formation processes that went into the creation of a land snail-dominated late- to post-glacial midden from northern Vietnam, and considers the role that it may have played in the early settlement of this area. The data presented comes from ongoing archaeological excavations at Hang Boi, a cave located in the sub-coastal karstic uplands of Trang An park, in the Vietnamese Province of Ninh Binh. (C) 2010 Elsevier Ltd and INQUA. All rights reserved.

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The Terminal Pleistocene zooarchaeological evidence from Lobang Hangus, an east-facing entrance to the Niah Cave complex, provides unique insights into the hunting habits of the human inhabitants of this cave. The composition and structure of the vertebrate accumulation indicates that a variety of locally available terrestrial, arboreal and aquatic taxa were being exploited, The age structure of the principal predated species, the presence of bone points and evidence from modern rainforest hunting combine to suggest that some form of projectile weaponry as well as trapping technologies were probably being employed by the hunters at Niah before the end of the Pleistocene. Copyright (C) 2009 John Wiley & Sons, Ltd.

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From 1989 to 1994 a series of papers outlined evidence for a brief episode of climate change from arid to humid, and then back to arid, during the Carnian Stage of the late Triassic. This time of climate change was compared to marine and terrestrial biotic changes, mainly extinction and then radiation of flora and fauna. Subsequently termed, albeit incorrectly, the Carnian Pluvial Event (CPE) by successive authors, interest in this episode of climatic change has increased steadily, with new evidence being published as well as several challenges to the theory. The exact nature of this humid episode, whether reflecting widespread precipitation or more local effects, as well as its ultimate cause remains equivocal. Bed-by-bed sampling of the Carnian in the Southern Alps (Dolomites), shows the episode began with a negative carbon isotope excursion that lasted for only part of one ammonoid zone (A. austriacum). However, that the Carnian Humid Episode represents a significantly longer period, both environmentally and biotically, is irrefutable. The evidence is strongest in the European, Middle East, Himalayan, North American and Japanese successions, but not always so clear in South America, Antarctica and Australia. The eruption of the Wrangellia Large Igneous Province and global warming (causing increased evaporation in the Tethyan and Panthalassic oceans) are suggested as causes for the humid episode.

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Volatiles erupted from large-scale explosive volcanic activities have a significant impact on climate and environmental changes. As an important ecological factor, the occurrence of fire is affected by vegetation cover, and fire can feed back into both vegetation and climatic change. The causes of fire events are diverse; and can include volcanic eruptions. The amount of charcoal in sediment sequences is related to the frequency and intensity of fire, and hence under good preservation conditions fire history can be reconstructed from fossil charcoal abundance. Until now, little research on the role of fire has been carried out in northeastern China. In this study, through research on charcoal and tephra shards from Gushantun and Hanlongwan, Holocene vegetation change in relation to fire and volcanic events in Jilin, Northeastern China, was investigated. Where tephra shards are present in Gushantun it is associated with low level of both conifers and broadleaved trees, and is also associated with a pronounced charcoal peak. This suggests forest cover was greatly reduced from a fire caused by an eruption of the Tianchi volcano. We also detected one tephra layer in Hanlongwan, which also has the almost same depth with low level forest pollen values and one charcoal peak. This was caused probably by an eruption of the Jinlongdingzi volcano.

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Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.

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Molecular Medicine and Molecular Pathology are integral parts of Haematology as we enter the new millennium. Their origins can be linked to fundamental developments in the basic sciences, particularly genetics, chemistry and biochemistry. The structure of DNA and the genetic code that it encrypts are the critical starting points to our understanding of these new disciplines. The genetic alphabet is a simple one, consisting of just 4 letters, buts its influence is crucial to human development and differentiation. The concept of a gene is not a new one but the Human Genome Project (a joint world-wide effort to characterise our entire genetic make-up) is providing an invaluable understanding of how genes function in normal cellular processes and pinpointing how disruption of these processes can lead to disease. Transcription and translation are the key events by which our genotype is converted to our phenotype (via a messenger RNA intermediate), producing the myriad proteins and enzymes which populate the cellular factory of our body. Unlike the bacterial or prokaryotic genome, the human genome contains a large amount of non coding DNA (less than 1% of our genome codes for proteins), and our genes are interrupted, with the coding regions or exons separated by non coding introns. Precise removal of the intronic material after transcription (though a process called splicing) is critical for efficient translation to occur. Incorrect splicing can lead to the generation of mutant proteins, which can have a dilaterious effect on the phenotype of the individual. Thus the 100,000-200,000 genes which are present in each cell in our body have a defined control mechanism permitting efficient and appropriate expression of proteins and enzymes and yet a single base change in just one of those genes can lead to diseases such as haemophilia or fanconis anaemia.

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The Neolithic and Bronze Age transitions were profound cultural shifts catalyzed in parts of Europe by migrations, first of early farmers from the Near East and then Bronze Age herders from the Pontic Steppe. However, a decades-long, unresolved controversy is whether population change or cultural adoption occurred at the Atlantic edge, within the British Isles. We address this issue by using the first whole genome data from prehistoric Irish individuals. A Neolithic woman (3343–3020 cal BC) from a megalithic burial (10.3× coverage) possessed a genome of predominantly Near Eastern origin. She had some hunter–gatherer ancestry but belonged to a population of large effective size, suggesting a substantial influx of early farmers to the island. Three Bronze Age individuals from Rathlin Island (2026–1534 cal BC), including one high coverage (10.5×) genome, showed substantial Steppe genetic heritage indicating that the European population upheavals of the third millennium manifested all of the way from southern Siberia to the western ocean. This turnover invites the possibility of accompanying introduction of Indo-European, perhaps early Celtic, language. Irish Bronze Age haplotypic similarity is strongest within modern Irish, Scottish, and Welsh populations, and several important genetic variants that today show maximal or very high frequencies in Ireland appear at this horizon. These include those coding for lactase persistence, blue eye color, Y chromosome R1b haplotypes, and the hemochromatosis C282Y allele; to our knowledge, the first detection of a known Mendelian disease variant in prehistory. These findings together suggest the establishment of central attributes of the Irish genome 4,000 y ago.

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BACKGROUND: As progress is made towards attaining Millennium Development Goal 4, further reductions in paediatric mortality will only be achieved by concentrating on the burden of non-communicable or neglected diseases. The literature relating to paediatric cardiac disease in sub-Saharan Africa is sparse. There are no published descriptions of paediatric cardiac disease from Malawi, making it impossible to estimate the contribution it makes to childhood morbidity and mortality.

FINDINGS: In 2008, a paediatric cardiac clinic with echocardiogram scanning was established in Blantyre, southern Malawi. Between January 2009 and February 2011, the age and cardiac diagnosis of every child with an abnormal echocardiogram was recorded in a database. Of 250 children, 139 (55.6%) had congenital heart disease, and 111 (44.4%) acquired heart disease. Ventricular septal defect (VSD) (24%), Tetralogy of Fallot (10%) and patent ductus arteriousus (7.2%) were the commonest forms of congenital heart disease. Rheumatic heart disease (RHD) (22.4%) and dilated cardiomyopathy (13.6%) were the commonest acquired diseases. The mean age of presentation was 3 years 2 months for VSD and 11 years 6 months for RHD.

CONCLUSIONS: In this cohort of children from one centre in Malawi, acquired heart disease - in particular rheumatic heart disease was almost as common as congenital heart disease. Most presented late. It is likely that untreated cardiac disease causes a large number of childhood deaths in Malawi. In addition to renewing secondary preventative efforts against rheumatic heart disease, adequate and accessible cardiothoracic surgical services should be established at a regional level.