233 research outputs found

    Extrasolar Planet Transits Observed at Kitt Peak National Observatory

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    We obtained J-, H- and JH-band photometry of known extrasolar planet transiting systems at the 2.1-m Kitt Peak National Observatory Telescope using the FLAMINGOS infrared camera between October 2008 and October 2011. From the derived lightcurves we have extracted the mid-transit times, transit depths and transit durations for these events. The precise mid-transit times obtained help improve the orbital periods and also constrain transit-time variations of the systems. For most cases the published system parameters successfully accounted for our observed lightcurves, but in some instances we derive improved planetary radii and orbital periods. We complemented our 2.1-m infrared observations using CCD z'-band and B-band photometry (plus two Hydrogen Alpha filter observations) obtained with the Kitt Peak Visitor's Center telescope, and with four H-band transits observed in October 2007 with the NSO's 1.6-m McMath-Pierce Solar Telescope. The principal highlights of our results are: 1) our ensemble of J-band planetary radii agree with optical radii, with the best-fit relation being: (Rp/R*)J = 0.0017 + 0.979 (Rp/R*)optical, 2) We observe star spot crossings during the transit of WASP-11/HAT-P-10, 3) we detect star spot crossings by HAT-P-11b (Kepler-3b), thus confirming that the magnetic evolution of the stellar active regions can be monitored even after the Kepler mission has ended, and 4) we confirm a grazing transit for HAT-P-27/WASP-40. In total we present 57 individual transits of 32 known exoplanet systems.Comment: 33 pages, 6 figures, accepted in Publications of the Astronomical Society of the Pacifi

    Developing a typology for peer education and peer support delivered by prisoners

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    Peer interventions delivered for prisoners by prisoners offer a means to improve health and reduce risk factors for this population. The variety of peer programs poses challenges for synthesizing evidence. This paper presents a typology developed as part of a systematic review of peer interventions in prison settings. Peer interventions are grouped into four modes: peer education, peer support, peer mentoring and bridging roles, with the addition of a number of specific interventions identified through the review process. The paper discusses the different modes of peer delivery with reference to a wider health promotion literature on the value of social influence and support. In conclusion, the typology offers a framework for developing the evidence base across a diverse field of practice in correctional health care

    (Invited) The inversion behaviour of narrow band gap MOS systems: experimental observations, physics based simulations and applications

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    Impedance spectroscopy of the metal-oxide semiconductor (MOS) system has played a central role in the development of silicon-based complementary MOS (CMOS) technology over the past 50 years [1, 2]. With current research interest into alternative semiconductor channels to silicon for MOSFET and tunnel FET technologies, the measurement and interpretation of the overall impedance of the MOS structure requires detailed analysis to separate and quantify the contribution of interface states, and near interface traps (border traps), on the capacitance and conductance response, and to separate the contribution of these electrically active defect states from the ac response of minority carriers in the case of genuine inversion of the semiconductor/dielectric interface

    A qualitative synthesis of the positive and negative impacts related to delivery of peer-based health interventions in prison settings

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    Background Peer interventions involving prisoners in delivering peer education and peer support in a prison setting can address health need and add capacity for health services operating in this setting. This paper reports on a qualitative synthesis conducted as part of a systematic review of prison-based peer interventions. One of the review questions aimed to investigate the positive and negative impacts of delivering peer interventions within prison settings. This covered organisational and process issues relating to peer interventions, including prisoner and staff views. Methods A qualitative synthesis of qualitative and mixed method studies was undertaken. The overall study design comprised a systematic review involving searching, study selection, data extraction and validity assessment. Studies reporting interventions with prisoners or ex-prisoners delivering education or support to prisoners resident in any type of prison or young offender institution, all ages, male and female, were included. A thematic synthesis was undertaken with a subset of studies reporting qualitative data (n=33). This involved free coding of text reporting qualitative findings to develop a set of codes, which were then grouped into thematic categories and mapped back to the review question. Results Themes on process issues and wider impacts were grouped into four thematic categories: peer recruitment training and support; organisational support; prisoner relationships; prison life. There was consistent qualitative evidence on the need for organisational support within the prison to ensure smooth implementation and on managing security risks when prisoners were involved in service delivery. A suite of factors affecting the delivery of peer interventions and the wider organisation of prison life were identified. Alongside reported benefits of peer delivery, some reasons for non-utilisation of services by other prisoners were found. There was weak qualitative evidence on wider impacts on the prison system, including better communication between staff and prisoners. Gaps in evidence were identified. Conclusions The quality of included studies limited the strength of the conclusions. The main conclusion is that peer interventions cannot be seen as independent of prison life and health services need to work in partnership with prison services to deliver peer interventions. More research is needed on long-term impacts

    Tyrosine Phosphorylation of the E3 Ubiquitin Ligase TRIM21 Positively Regulates Interaction with IRF3 and Hence TRIM21 Activity

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    Patients suffering from Systemic Lupus Erythematous (SLE) have elevated type I interferon (IFN) levels which correlate with disease activity and severity. TRIM21, an autoantigen associated with SLE, has been identified as an ubiquitin E3 ligase that targets the transcription factor IRF3 in order to turn off and limit type I IFN production following detection of viral and bacterial infection by Toll Like Receptors (TLRs). However, how the activity of TRIM21 is regulated downstream of TLRs is unknown. In this study we demonstrate that TRIM21 is tyrosine phosphorylated following TLR3 and TLR4 stimulation, suggesting that its activity is potentially regulated by tyrosine phosphorylation. Using Netphos, we have identified three key tyrosines that are strongly predicted to be phosphorylated, two of which are conserved between the human and murine forms of TRIM21, at residues 343, 388, and 393, all of which have been mutated from tyrosine to phenylalanine (Y343F, Y388F, and Y393F). We have observed that tyrosine phosphorylation of TRIM21 only occurs in the substrate binding PRY/SPRY domain, and that Y393, and to a lesser extent, Y388 are required for TRIM21 to function as a negative regulator of IFN-β promoter activity. Further studies revealed that mutating Y393 to phenylalanine inhibits the ability of TRIM21 to interact with its substrate, IRF3, thus providing a molecular explanation for the lack of activity of Y393 on the IFN-β promoter. Our data demonstrates a novel role for tyrosine phosphorylation in regulating the activity of TRIM21 downstream of TLR3 and TLR4. Given the pathogenic role of TRIM21 in systemic autoimmunity, these findings have important implications for the development of novel therapeutics

    Structural and Electrical Properties of HfO2/n-InxGa1-xAs structures (x: 0, 0.15, 0.3 and 0.53)

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    7th International Symposium on High Dielectric Constant Materials and Gate Stacks - 216th Meeting of the Electrochemical Society; Vienna; Austria; 5 October 2009 through 7 October 2009; Code 79118In this work results are presented of an investigation into the structural and electrical properties of HfO2 films on GaAs and InxGa1-xAs substrates for x: 0.15, 0.30, and 0.53. The capacitancevoltage responses of the GaAs and InxGa1-xAs (x: 0.15 and 0.30) are dominated by an interface defect response. Analysis of these samples at 77K indicates that the defect density is > 2.5x1013 cm-2. For the HfO2/In0.53Ga0.47As system, 77K capacitance-voltage responses indicate surface accumulation is achieved. The results are consistent with a high defect density, with an energy level {greater than or equal to}0.75 eV above the valence band in the HfO2/InxGa1-xAs system, where the defect energy with respect to the valence band, does not change with the composition of the InxGa1-xAs. The HfO2/In0.53Ga0.47As interface exhibits two defects at 0.3eV (1.7x1013cm-2eV) and 0.61eV (1.5x1013cm-2eV) above the valance band edge. The defect at 0.61eV is removed by forming gas annealing at 325oC
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