586 research outputs found

    Shape coexistence from lifetime and branching-ratio measurements in 68,70Ni

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    © 2016 The Author(s) Shape coexistence near closed-shell nuclei, whereby states associated with deformed shapes appear at relatively low excitation energy alongside spherical ones, is indicative of the rapid change in structure that can occur with the addition or removal of a few protons or neutrons. Near 68Ni (Z=28, N=40), the identification of shape coexistence hinges on hitherto undetermined transition rates to and from low-energy 0+ states. In 68,70Ni, new lifetimes and branching ratios have been measured. These data enable quantitative descriptions of the 0+ states through the deduced transition rates and serve as sensitive probes for characterizing their nuclear wave functions. The results are compared to, and consistent with, large-scale shell-model calculations which predict shape coexistence. With the firm identification of this phenomenon near 68Ni, shape coexistence is now observed in all currently accessible regions of the nuclear chart with closed proton shells and mid-shell neutrons

    The composition of the protosolar disk and the formation conditions for comets

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    Conditions in the protosolar nebula have left their mark in the composition of cometary volatiles, thought to be some of the most pristine material in the solar system. Cometary compositions represent the end point of processing that began in the parent molecular cloud core and continued through the collapse of that core to form the protosun and the solar nebula, and finally during the evolution of the solar nebula itself as the cometary bodies were accreting. Disentangling the effects of the various epochs on the final composition of a comet is complicated. But comets are not the only source of information about the solar nebula. Protostellar disks around young stars similar to the protosun provide a way of investigating the evolution of disks similar to the solar nebula while they are in the process of evolving to form their own solar systems. In this way we can learn about the physical and chemical conditions under which comets formed, and about the types of dynamical processing that shaped the solar system we see today. This paper summarizes some recent contributions to our understanding of both cometary volatiles and the composition, structure and evolution of protostellar disks.Comment: To appear in Space Science Reviews. The final publication is available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-

    Functional diversity of chemokines and chemokine receptors in response to viral infection of the central nervous system.

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    Encounters with neurotropic viruses result in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences to relatively benign infection. One of the principal factors that control the outcome of infection is the localized tissue response and subsequent immune response directed against the invading toxic agent. It is the role of the immune system to contain and control the spread of virus infection in the central nervous system (CNS), and paradoxically, this response may also be pathologic. Chemokines are potent proinflammatory molecules whose expression within virally infected tissues is often associated with protection and/or pathology which correlates with migration and accumulation of immune cells. Indeed, studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV), have provided important insight into the functional roles of chemokines and chemokine receptors in participating in various aspects of host defense as well as disease development within the CNS. This chapter will highlight recent discoveries that have provided insight into the diverse biologic roles of chemokines and their receptors in coordinating immune responses following viral infection of the CNS

    Environmental baseline monitoring : Phase III final report (2017-2018)

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    High-quality environmental baseline monitoring data are being collected in areas around two proposed shale gas sites near Kirby Misperton, North Yorkshire and Little Plumpton Lancashire. Monitoring has now been on-going for over two years and has produced an internationally unique data set that will allow any future changes that arise from industrial activities at either or both shale gas sites to be detected and characterised, as well as providing a significant resource for future research. The monitoring includes: water quality, air quality, seismicity, ground motion, soil gas and radon in air. This report presents the results of monitoring in the Vale of Pickering, within which the Kirby Misperton shale gas site (KM8) is located, for the period April 2017–March 2018. It also includes the results of atmospheric composition measurements made near the Little Plumpton (Preston New Road) site. Earlier results and other monitoring in Lancashire are reported elsewhere and can be accessed from the British Geological Survey’s website1. As well as providing valuable insight into the importance of establishing robust information on the conditions before shale gas operations start, it also highlights the challenges in establishing effective monitoring and producing reliable results. For groundwater, this includes the importance of: developing and flushing newly installed boreholes; the spatial variation in water quality and; the selection of monitoring and measuring techniques. Having two years of data has allowed comparison between years. The preliminary analysis reported here has shown that sample populations were not significantly different between the two years. This is directly relevant to the duration of monitoring required by legislation, with the evidence supporting a baseline monitoring period of at least 12 months before any site operations start. The seismic monitoring network installed for measuring background seismicity has operated successfully throughout the reporting period. All but one station show levels of data completeness over 90% which represents a high-quality dataset. There has been no significant change in recorded noise levels at any of the stations in the network. This combined with instrument performance means the network is capable of detecting seismic events with magnitudes of 0.5 ML or less around Kirby Misperton. The monitoring has detected successfully a number of earthquakes around both the Vale of Pickering and the Fylde peninsula. However, all of these are at some distance from the shale gas sites. The Vale of Pickering network has also detected a number of other seismic events that have been attributed to quarry blasts. The magnitudes of these events range from 0.7 ML to 1.6 ML. We have also developed and applied a new magnitude scale to correct for overestimation of magnitudes at small epicentral distances. This results in a significant reduction of the magnitudes of quarry blasts in the Vale of Pickering by over 0.5 magnitude units in some cases. The variance in the magnitude estimates is also slightly reduced. This issue is critical for correct estimation of the magnitudes of any earthquakes that might be induced by hydraulic fracturing. The greenhouse gas monitoring continues to reinforce the conclusion that a baseline at one location is not applicable to other locations. However, the consistency of the baseline measurements (and baseline variability within each year) at both sites clearly suggests that 12 months of baseline monitoring is sufficient to establish a meaningful climatology to compare with analogous climatologies during the operational lifetime of the shale gas sites. Twelve months of data allow differentiation of local and long-range sources of greenhouse gases. At both sites, local (<10 km) sources dominate the contribution to statistically elevated concentration observations. We conclude that: the consistency of the baseline statistics year-to-year at each site separately, strongly validates the utility of these statistics in future comparative work; repeatability and similarity in both mean and statistical variability at each individual site across both annual periods suggests that 12 months of monitoring is sufficient to characterise the baseline at future sites usefully and; the large differences between the baselines at both sites, due to influence of local sources, demonstrate that careful thought and further work may be required to assess the spatial scale over which baselines can be usefully applicable. The baseline distribution of air pollutants measured at the Lancashire site has been broadly similar in 2017 to previous years, but there have been substantial changes observed at Kirby Misperton. There was a noticeable increase in NOx from Autumn 2017 as the site was prepared for hydraulic fracturing operations to begin. The high level of vehicle movements and operation of equipment during this period led to enhanced local NOx emissions. The equipment was removed after operations were suspended and the NOx concentrations returned to broadly the same concentrations seen previously during the baseline period. This highlights the importance of measuring the whole shale-gas operational cycle for air quality as the preparative operations can have a substantial impact on air pollution. In the Vale of Pickering, 133 households volunteered to have detectors for measuring indoor radon concentrations. The results were consistent with the usual log-normal distribution for indoor radon and reflected the locations of the monitoring with respect to whether they were in Radon Affected Areas or not, i.e. radon levels above 200 Bq/m3 were measured in homes in Malton which confirmed the PHE/BGS classification of this location as a Radon Affected Area. Outdoor radon was also measured. There is no indication of elevated outdoor radon concentrations in either the Pickering or Malton Radon Affected Areas, or elsewhere. Results from an active monitor and passive detectors, placed on the Kirby Misperton well site were in good agreement with the average outdoor radon concentrations for the area around Kirby Misperton. The active monitoring showed significant short-term variations over time. However the annual average was consistent, whichever of the techniques was used. Seasonal variability in baseline soil gas and flux values continues to be observed as well as shorter-term diurnal changes and event-driven variations, for example related to the passage of weather systems. The longer-time-series data and the preliminary geostatistical appraisal of selected data suggest that any emissions related to shale gas operations will be easiest to detect in the autumn when baseline biological activity is lower and the soil remains dry. Saturation of the ground in the winter months precludes free gas measurements. A further component of the study is to characterise ground motion (subsidence and/or uplift) in the study areas using satellite data. The objective being to determine what the current situation is, so that any changes that might be caused by hydraulic fracturing, if it takes place, can be identified. The baseline conditions have previously been reported (Ward et al, 2018) and as now hydraulic fracturing has yet taken place, no further analysis has been carried out during this reporting period

    Environmental monitoring : phase 5 final report (April 2019 - March 2020)

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    This report presents the results and interpretation for Phase 5 of an integrated environmental monitoring programme that is being undertaken around two proposed shale gas sites in England – Preston New Road, Lancashire and Kirby Misperton, North Yorkshire. The report should be read in conjunction with previous reports freely available through the project website1 . These provide additional background to the project, presentation of earlier results and the rationale for establishment of the different elements of the monitoring programme

    Environmental monitoring : phase 4 final report (April 2018 - March 2019)

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    This report describes the results of activities carried out as part of the Environmental Monitoring Project (EMP) led by the British Geological Survey (BGS) in areas around two shale gas sites in England – Kirby Misperton (Vale of Pickering, North Yorkshire) and Preston New Road (Fylde, Lancashire). It focuses on the monitoring undertaken during the period April 2018–March 2019 but also considers this in the context of earlier monitoring results that have been covered in reports for earlier phases of the project (Phases I–IV) 2 . The EMP project is a multi-partner project involving BGS together with Public Health England (PHE), University of Birmingham, University of Bristol, University of Manchester, Royal Holloway University of London (RHUL) and University of York. The work has been enabled by funding from a combination of the BGS National Capability programme, a grant awarded by the UK Government’s Department for Business Energy & Industrial Strategy (BEIS) and additional benefit-in-kind contributions from all partners. The project comprises the comprehensive monitoring of different environment compartments and properties at and around the two shale-gas sites. The component parts of the EMP are all of significance when considering environmental and human health risks associated with shale gas development. Included are seismicity, ground motion, water (groundwater and surface water), soil gas, greenhouse gases, air quality, and radon. The monitoring started before hydraulic fracturing had taken place at the two locations, and so the results obtained before the initiation of operations at the shale-gas sites represent baseline conditions. It is important to characterise adequately the baseline conditions so that any future changes caused by shale gas operations, including hydraulic fracturing, can be identified. This is also the case for any other new activities that may impact those compartments of the environment being monitored as part of the project. In the period October 2018–December 2018, an initial phase of hydraulic fracturing took place at the Preston New Road (PNR) shale-gas site (shale gas well PNR1-z) in Lancashire. This was followed by a period of flow testing of the well to assess its performance (to end of January 2019). The project team continued monitoring during these various activities and several environmental effects were observed. These are summarised below and described in more detail within the report. The initiation of operations at the shale-gas site signified the end of baseline monitoring. At the Kirby Misperton site (KMA), approval has not yet been granted for hydraulic fracturing of the shale gas well (KM8), and so no associated operations have taken place during the period covered by this report. The effects on air quality arising from the mobilisation of equipment in anticipation of hydraulic fracturing operations starting was reported in the Phase III report, and in a recently published paper3 . Following demobilisation of the equipment and its removal from the site, conditions returned to baseline and the on-going monitoring (reported in this report) is effectively a continuation of baseline monitoring

    SPACA3gene variants in a New Zealand cohort of infertile and fertile couples

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    SPRASA (also referred to as SLLP1) is a protein identified in the acrosome of human sperm and encoded by the gene SPACA3. SPRASA is associated with sperm-oocyte recognition and binding, and may play a role in fertility. In order to determine whether variants in the SPACA3 gene are associated with human infertility, we undertook a genetic analysis of 102 infertile and 104 fertile couples. Three gene variants were identified using PCR-based DNA sequencing; 1) an insertion of TGC within a quadruple tri-nucleotide (TGC) repeat region in the 5’ untranslated region (UTR) (g.–22TGC(4_5), 2) a guanine to adenosine transition at position 239 (c.239G> A) resulting in a non-synonymous amino acid substitution from cysteine to tyrosine (p.C80Y) at position 80 in the putative transmembrane region, and 3) a novel nucleotide variant (c.691G> C) located in the 3’UTR. A functional effect of the g.–22TGC (4_5) was confirmed by a luciferase expression assay, while the effects of the variants c.239G> A and c.691G> C were predicted using in silico analysis. Although the frequencies of these variants were not significantly different between the infertile and fertile populations, we present evidence that the variants could affect the expression levels or function of SPRASA, thereby affecting a couple's fertility. Larger populations, especially individuals/couples with unexplained infertility, need to be screened for these variants to validate a relationship with fertility

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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