991 resultados para Rare events


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Data on rock temperatures has previously been collected to characterise typical diurnal regimes, and more recently to describe short-term variability in extreme locations. However, there is also the case that little is understood concerning the impact of extreme events in otherwise temperate environments. Internal stone temperatures (5?cm) collected during the atypical cold extreme experienced, throughout the UK, in December 2010 show a difference between ambient air temperatures and aspect-related thermal differences, particularly concerning temperature lows and the influence of radiative heating. In this case, debris release was not visible; however, laboratory simulations have shown that under such conditions, surface loss does not necessarily negate the occurrence of internal stone modifications. This preparatory sequence of change demonstrates that surface loss is not the result of one process, but rather many operating over time to sufficiently decrease stone strength to facilitate obvious damage.

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To investigate whether work related stress, measured and defined as job strain, is associated with the overall risk of cancer and the risk of colorectal, lung, breast, or prostate cancers.

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The search for materials or systems exhibiting a high magnetic saturation has been of longstanding importance. It has been suggested that increased saturation could be achieved by coupling a transition metal via a spacer to a rare earth. We report Gd/Cr/Fe70Co30 multilayer stacks and find reduced yet modulating magnetic moment as a function of Cr thickness. Through a micro structural analysis the lowered moment is indicated by the nucleation of the ultrathin Gd films into an fcc phase. We discuss the possible solution in terms of quasi-perfect lattice match seed material to promote growth of hcp Gd.

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Colistin resistance is rare in Acinetobacter baumannii, and little is known about its mechanism. We investigated the role of PmrCAB in this trait, using (i) resistant and susceptible clinical strains, (ii) laboratory-selected mutants of the type strain ATCC 19606 and of the clinical isolate ABRIM, and (iii) a susceptible/resistant pair of isogenic clinical isolates, Ab15/133 and Ab15/132, isolated from the same patient. pmrAB sequences in all the colistin-susceptible isolates were identical to reference sequences, whereas resistant clinical isolates harbored one or two amino acid replacements variously located in PmrB. Single substitutions in PmrB were also found in resistant mutants of strains ATCC 19606 and ABRIM and in the resistant clinical isolate Ab15/132. No mutations in PmrA or PmrC were found. Reverse transcriptase (RT)-PCR identified increased expression of pmrA (4- to 13-fold), pmrB (2- to 7-fold), and pmrC (1- to 3-fold) in resistant versus susceptible organisms. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry showed the addition of phosphoethanolamine to the hepta-acylated form of lipid A in the resistant variants and in strain ATCC 19606 grown under low-Mg induction conditions. pmrB gene knockout mutants of the colistin-resistant ATCC 19606 derivative showed >100-fold increased susceptibility to colistin and 5-fold decreased expression of pmrC; they also lacked the addition of phosphoethanolamine to lipid A. We conclude that the development of a moderate level of colistin resistance in A. baumannii requires distinct genetic events, including (i) at least one point mutation in pmrB, (ii) upregulation of pmrAB, and (iii) expression of pmrC, which lead to addition of phosphoethanolamine to lipid A. Copyright © 2011, American Society for Microbiology. All Rights Reserved.

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Our review of paleoclimate information for New Zealand pertaining to the past 30,000 years has identified a general sequence of climatic events, spanning the onset of cold conditions marking the final phase of the Last Glaciation, through to the emergence to full interglacial conditions in the early Holocene. In order to facilitate more detailed assessments of climate variability and any leads or lags in the timing of climate changes across the region, a composite stratotype is proposed for New Zealand. The stratotype is based on terrestrial stratigraphic records and is intended to provide a standard reference for the intercomparison and evaluation of climate proxy records. We nominate a specific stratigraphic type record for each climatic event, using either natural exposure or drill core stratigraphic sections. Type records were selected on thebasis of having very good numerical age control and a clear proxy record. In all cases the main proxy of the type record is subfossil pollen. The type record for the period from ca 30 to ca 18 calendar kiloyears BP (cal. ka BP) is designated in lake-bed sediments from a small morainic kettle lake (Galway tarn) in western South Island. The Galway tarn type record spans a period of full glacial conditions (Last Glacial Coldest Period, LGCP) within the Otira Glaciation, and includes three cold stadials separated by two cool interstadials. The type record for the emergence from glacial conditions following the termination of the Last Glaciation (post-Termination amelioration) is in a core of lake sediments from a maar (Pukaki volcanic crater) in Auckland, northern North Island, and spans from ca 18 to 15.64±0.41 cal. ka BP. The type record for the Lateglacial period is an exposure of interbedded peat and mud at montane Kaipo bog, eastern North Island. In this high-resolution type record, an initial mild period was succeeded at 13.74±0.13 cal. ka BP by a cooler period, which after 12.55±0.14 cal. ka BP gave way to a progressive ascent to full interglacial conditions that were achieved by 11.88±0.18 cal. ka BP. Although a type section is not formally designated for the Holocene Interglacial (11.88±0.18 cal. ka BP to the present day), the sedimentary record of Lake Maratoto on the Waikato lowlands, northwestern North Island, is identified as a prospective type section pending the integration and updating of existing stratigraphic and proxy datasets, and age models. The type records are interconnected by one or more dated tephra layers, the ages of which are derived from Bayesian depositional modelling and OxCal-based calibrations using the IntCal09 dataset. Along with the type sections and the Lake Maratoto record, important, well-dated terrestrial reference records are provided for each climate event. Climate proxies from these reference records include pollen flora, stable isotopes from speleothems, beetle and chironomid fauna, and glacier moraines. The regional composite stratotype provides a benchmark against which to compare other records and proxies. Based on the composite stratotype, we provide an updated climate event stratigraphic classification for the New Zealand region. © 2013 Elsevier Ltd.

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Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10,337 cases and 11,174 controls (OR=1.10; p-value=3.79×10(-5)). Thus, it appears that rare and common variants in a single gene - FBN2 - can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

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To test the applicability of the sex-specific 2008 Framingham general cardiovascular risk equation for coronary heart disease (CHD) and stroke in European middle-aged men from Ireland and France.

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Despite being the most suitable candidates for solenoid pole pieces in state-of-the-art superconductor- based electromagnets, the intrinsic magnetic properties of heavy rare earth metals and their alloys have gained comparatively little attention. With the potential of integration in micro- and nanoscale devices, thin films of Gd, Dy, Tb, DyGd and DyTb were plasma-sputtered and investigated for their in-plane magnetic properties, with an emphasis on magnetisation vs. temperature profiles. Based on crystal structure analysis of the polycrystalline rare earth films, which consist of a low magnetic moment FCC layer at the seed interface topped with a higher moment HCP layer, an experimental protocol is introduced which allows the direct magnetic analysis of the individual layers. In line with the general trend of heavy lanthanides, the saturation magnetisation was found to drop with increasing unit cell size. In-situ annealed rare earth films exceeded the saturation magnetisation of a high-moment Fe65Co35 reference film in the cryogenic temperature regime, proving their potential for pole piece applications; however as-deposited rare earth films were found completely unsuitable. In agreement with theoretical predictions, sufficiently strained crystal phases of Tb and Dy did not exhibit an incommensurate magnetic order, unlike their single-crystal counterparts which have a helical phase. DyGd and DyTb alloys followed the trends of the elemental rare earth metals in terms of crystal structure and magnetic properties. Inter-rare-earth alloys hence present a desirable blend of saturation magnetisation and operating temperature.

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Sport Mega-event hosting faces opposition that is manifested with different intensity during the different phases of the event, from its inception as an idea to its delivery and legacy. Some Social Movements Organisations (SMOs) have acted as indefatigable monitors of the Sustainable Development (SD) dimension of sporting events in general and, in some of the most recent sport mega-events, in particular the Olympics, they have served as important advisors and facilitators. Nevertheless, in many cases we see enthusiastic supporters turning to vehemently challenging whatever positives have been associated with hosting the event. In addition, there is opposition to sport Mega-events in their entirety. That type of opposition tends to employ a holistic prism that manages to identify multiple interconnected negative aspects of hosting a sport mega-event and incorporate them into an anti-systemic discourse. It is important to bear in mind that irrespective of many proclamations to the opposite as far as megas are concerned (projects and/or events), a number of studies have demonstrated that citizen participation and democratic accountability in decision-making have been notoriously absent. After all, the idea of citizen participation in the planning of sport mega-event is essentially the public response to a plan conceived by others. There were, of course, some notable cases of democratic consultation at the early stages of bidding to host a sport mega-event but these more democratic approaches resulted in the failure of the bid (for e.g. Toronto 1996). The knowledge of this by the groups that initiated the hosting idea and the bidding process has led to discouraging in depth public consultation that may fit perfectly to the democratic process but not to the tight schedules of associated projects completion. That produces ‘autocracy against which opposition may arise’ (Hiller, 2000, p. 198). It is this democratic deficit that has led to important instances of social contestation and protest mobilizations by citizen groups as well as the more regular corps of social activists. From a perspective borrowed from the sociology of protest and social movements, sport mega-events hosting can operate as an issue that stimulates protest activities by an existing protest milieu and new actors as well as an important mobilizing resource. In fact, some scholars have also argued that the Olympic Games were an important frame for the transnational activism that was marked by anti-globalization protest in Seattle in 1999 (Cottrell & Nelson, 201; Lenskyj, 2008). In addition, it’s important not to lose sight of other acts dissent that take place in relatively close proximity, about a year before the event when most infrastructural and societal changes brought by hosting the event and impact start to become apparent by the host communities, like the rioting of August 2011 in the London Olympic Boroughs and the 2012 riots of June 2013 in Sao Paulo and other Brazilian cities. This paper starts by outlining the SD claims made in the bidding to host the summer Olympic Games by five prospective hosts (Sydney; Athens; Beijing; London and Rio) proceeds towards examining the opposition and challenges that was manifested in relation to these claims. In Particular it provides an assessment of protest-events over the aforementioned different phases of sport mega-events hosting. A different picture emerges for each of the host nation that is partly explained by local, national and global configuration of protest politics. Whereas the post-event legacy of the first two hosts of the Games can be assessed and that way see the validity of claims made by challengers in the other phases, in the other three cases, the implementation of Olympic Games Impact (OGI) studies offers the tool for discussing the post-event phase for Beijing and London and engage in a speculative exercise for the case of Rio. Judging by available findings, the paper concludes that the SD aspiration made in the bid documents are unlikely to be met and social contestation based on the same issues is likely to increase due to the current global economic crisis and BRICS, like China and Brazil, having entered the process of becoming global economic hegemons.

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This article examines the difficulties of finding local solutions to the problem of contentious events in contemporary Northern Ireland. In so doing, it offers a sociological perspective on fundamental divisions in Northern Ireland: between classes and between communities. It shows how its chosen case study—parades and associated protests in north Belfast—exemplifies the most fundamental problem that endures in post-Agreement Northern Ireland, namely that political authority is not derived from a common civic culture (as is the norm in Western liberal democracy) but rather that legitimacy is still founded on the basis of the culture of either one or the other community. Haugaard’s reflections on authority and legitimacy are used to explore Northern Ireland’s atypical experience of political conflict vis-`a-vis the Western liberal democratic model. The Bourdieusian concepts of field illusio and doxa help to explain why it is that parading remains such an important political and symbolic touchstone in this society.