808 research outputs found

    Magnetosphereā€Ionosphereā€Thermosphere coupling at Jupiter using a threeā€dimensional atmospheric general circulation model

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    Jupiter's upper atmosphere is āˆ¼700 K hotter than predicted based on solar extreme ultraviolet heating alone. The reason for this still remains a mystery and is known as the ā€œenergy crisis.ā€ It is thought that the interaction between Jupiter and its dynamic magnetosphere plays a vital role in heating its atmosphere to the observed temperatures. Here, we present a new model of Jupiter's magnetosphereā€ionosphereā€thermosphereā€coupled system where we couple a threeā€dimensional atmospheric general circulation model to an axisymmetric magnetosphere model. We find that the model temperatures are on average āˆ¼60 K, with a maximum of āˆ¼200 K, hotter than the model's twoā€dimensional predecessor making our highā€latitude temperatures comparable to the lower limit of observations. Stronger meridional winds now transport more heat from the auroral region to the equator increasing the equatorial temperatures. However, despite this increase, the modeled equatorial temperatures are still hundreds of kelvins colder than observed. We use this model as an intermediate step toward a threeā€dimensional atmospheric model coupled to a realistic magnetosphere model with zonal and radial variation

    Evidence-informed health policy 1 ā€“ Synthesis of findings from a multi-method study of organizations that support the use of research evidence

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    Background: Organizations have been established in many countries and internationally to support the use of research evidence by producing clinical practice guidelines, undertaking health technology assessments, and/or directly supporting the use of research evidence in developing health policy on an international, national, and state or provincial level. Learning from these organizations can reduce the need to 'reinvent the wheel' and inform decisions about how best to organize support for such organizations, particularly in low- and middle-income countries (LMICs). Methods: We undertook a multi-method study in three phases ā€“ a survey, interviews, and case descriptions that drew on site visits ā€“ and in each of the second and third phases we focused on a purposive sample of those involved in the previous phase. We used the seven main recommendations that emerged from the advice offered in the interviews to organize much of the synthesis of findings across phases and methods. We used a constant comparative method to identify themes from across phases and methods. Results: Seven recommendations emerged for those involved in establishing or leading organizations that support the use of research evidence in developing health policy: 1) collaborate with other organizations; 2) establish strong links with policymakers and involve stakeholders in the work; 3) be independent and manage conflicts of interest among those involved in the work; 4) build capacity among those working in the organization; 5) use good methods and be transparent in the work; 6) start small, have a clear audience and scope, and address important questions; and 7) be attentive to implementation considerations, even if implementation is not a remit. Four recommendations emerged for the World Health Organization (WHO) and other international organizations and networks: 1) support collaborations among organizations; 2) support local adaptation efforts; 3) mobilize support; and 4) create global public goods. Conclusion: This synthesis of findings from a multi-method study, along with the more detailed findings from each of the three phases of the study (which are reported in the three following articles in the series), provide a strong basis on which researchers, policymakers, international organizations (and networks) like WHO can respond to the growing chorus of voices calling for efforts to support the use of research evidence in developing health policy

    Evidence-informed health policy 3 ā€“ Interviews with the directors of organizations that support the use of research evidence

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    Background: Previous surveys of organizations that support the development of evidence-informed health policies have focused on organizations that produce clinical practice guidelines (CPGs) or undertake health technology assessments (HTAs). Only rarely have surveys focused at least in part on units that directly support the use of research evidence in developing health policy on an international, national, and state or provincial level (i.e., government support units, or GSUs) that are in some way successful or innovative or that support the use of research evidence in low- and middle-income countries (LMICs). Methods: We drew on many people and organizations around the world, including our project reference group, to generate a list of organizations to survey. We modified a questionnaire that had been developed originally by the Appraisal of Guidelines, Research and Evaluation in Europe (AGREE) collaboration and adapted one version of the questionnaire for organizations producing CPGs and HTAs, and another for GSUs. We sent the questionnaire by email to 176 organizations and followed up periodically with non-responders by email and telephone. Results: We received completed questionnaires from 152 (86%) organizations. More than one-half of the organizations (and particularly HTA agencies) reported that examples from other countries were helpful in establishing their organization. A higher proportion of GSUs than CPG-or HTA-producing organizations involved target users in the selection of topics or the services undertaken. Most organizations have few (five or fewer) full-time equivalent (FTE) staff. More than four-fifths of organizations reported providing panels with or using systematic reviews. GSUs tended to use a wide variety of explicit valuation processes for the research evidence, but none with the frequency that organizations producing CPGs, HTAs, or both prioritized evidence by its quality. Between one-half and two-thirds of organizations do not collect data systematically about uptake, and roughly the same proportions do not systematically evaluate their usefulness or impact in other ways. Conclusion: The findings from our survey, the most broadly based of its kind, both extend or clarify the applicability of the messages arising from previous surveys and related documentary analyses, such as how the 'principles of evidence-based medicine dominate current guideline programs' and the importance of collaborating with other organizations. The survey also provides a description of the history, structure, processes, outputs, and perceived strengths and weaknesses of existing organizations from which those establishing or leading similar organizations can draw

    ACL reconstruction with unicondylar replacement in knee with functional instability and osteoarthritis

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    Severe symptomatic osteoarthritis in young and active patients with pre-existing deficiency of the anterior cruciate ligament and severe functionally instability is a difficult subgroup to manage. There is considerable debate regarding management of young patients with isolated unicompartment osteoarthritis and concomitant ACL deficiency. A retrospective analysis of was done in 9 patients with symptomatic osteoarthritis with ACL deficiencies and functional instability that were treated with unicompartment knee arthroplasty and ACL reconstruction between April 2002 and June 2005. The average arc of flexion was 119Ā° (range 85Ā° to 135Ā°) preoperatively and 125Ā° (range 105Ā° to 140Ā°). There were no signs of instability during the follow up of patients. No patients in this group were reoperated. In this small series we have shown that instability can be corrected and pain relieved by this combined procedure

    Calculating the QED correction to the hadronic vacuum polarisation on the lattice

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    Isospin-breaking corrections to the hadron vacuum polarization component of the anomalous magnetic moment of the muon are needed to ensure the theoretical precision of gĪ¼ - 2 is below the experimental precision. We describe the status of our work calculating, using lattice QCD, the QED correction to the light and strange connected hadronic vacuum polarization in a Dashen scheme. We report results using physical N f = 2 + 1 + 1 HISQ ensembles at three lattice spacings and three heavier-than-light valence quark masses

    Massive stars as thermonuclear reactors and their explosions following core collapse

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    Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most of the time are also considered. Stellar thermonuclear reactions involving protons in hydrostatic burning are discussed first. Then I discuss triple alpha reactions in the helium burning stage. Carbon and oxygen survive in red giant stars because of the nuclear structure of oxygen and neon. Further nuclear burning of carbon, neon, oxygen and silicon in quiescent conditions are discussed next. In the subsequent core-collapse phase, neutronization due to electron capture from the top of the Fermi sea in a degenerate core takes place. The expected signal of neutrinos from a nearby supernova is calculated. The supernova often explodes inside a dense circumstellar medium, which is established due to the progenitor star losing its outermost envelope in a stellar wind or mass transfer in a binary system. The nature of the circumstellar medium and the ejecta of the supernova and their dynamics are revealed by observations in the optical, IR, radio, and X-ray bands, and I discuss some of these observations and their interpretations.Comment: To be published in " Principles and Perspectives in Cosmochemistry" Lecture Notes on Kodai School on Synthesis of Elements in Stars; ed. by Aruna Goswami & Eswar Reddy, Springer Verlag, 2009. Contains 21 figure

    Structural analysis of MDM2 RING separates degradation from regulation of p53 transcription activity

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    MDM2ā€“MDMX complexes bind the p53 tumor-suppressor protein, inhibiting p53's transcriptional activity and targeting p53 for proteasomal degradation. Inhibitors that disrupt binding between p53 and MDM2 efficiently activate a p53 response, but their use in the treatment of cancers that retain wild-type p53 may be limited by on-target toxicities due to p53 activation in normal tissue. Guided by a novel crystal structure of the MDM2ā€“MDMXā€“E2(UbcH5B)ā€“ubiquitin complex, we designed MDM2 mutants that prevent E2ā€“ubiquitin binding without altering the RING-domain structure. These mutants lack MDM2's E3 activity but retain the ability to limit p53ā€²s transcriptional activity and allow cell proliferation. Cells expressing these mutants respond more quickly to cellular stress than cells expressing wild-type MDM2, but basal p53 control is maintained. Targeting the MDM2 E3-ligase activity could therefore widen the therapeutic window of p53 activation in tumors

    Hypoglycemia Assessed by Continuous Glucose Monitoring Is Associated with Preclinical Atherosclerosis in Individuals with Impaired Glucose Tolerance

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    Hypoglycemia is associated with increased risk of cardiovascular adverse clinical outcomes. There is evidence that impaired glucose tolerance (IGT) is associated with cardiovascular morbidity and mortality. Whether IGT individuals have asymptomatic hypoglycemia under real-life conditions that are related to early atherosclerosis is unknown. To this aim, we measured episodes of hypoglycemia during continuous interstitial glucose monitoring (CGM) and evaluated their relationship with early manifestation of vascular atherosclerosis in glucose tolerant and intolerant individuals. An oral glucose tolerance test (OGTT) was performed in 79 non-diabetic subjects. Each individual underwent continuous glucose monitoring for 72 h. Cardiovascular risk factors and ultrasound measurement of carotid intima-media thickness (IMT) were evaluated. IGT individuals had a worse cardiovascular risk profile, including higher IMT, and spent significantly more time in hypoglycemia than glucose-tolerant individuals. IMT was significantly correlated with systolic (rā€Š=ā€Š0.22; Pā€Š=ā€Š0.05) and diastolic blood pressure (rā€Š=ā€Š0.28; Pā€Š=ā€Š0.01), total (rā€Š=ā€Š0.26; Pā€Š=ā€Š0.02) and LDL cholesterol (rā€Š=ā€Š0.27; Pā€Š=ā€Š0.01), 2-h glucose (rā€Š=ā€Š0.39; P<0.0001), insulin sensitivity (rā€Š=ā€Šāˆ’0.26; Pā€Š=ā€Š0.03), and minutes spent in hypoglycemia (rā€Š=ā€Š0.45; P<0.0001). In univariate analyses adjusted for gender, minutes spent in hypoglycemia were significantly correlated with age (rā€Š=ā€Š0.26; Pā€Š=ā€Š0.01), waist circumference (rā€Š=ā€Š0.33; Pā€Š=ā€Š0.003), 2-h glucose (rā€Š=ā€Š0.58; P<0.0001), and 2-h insulin (rā€Š=ā€Š0.27; Pā€Š=ā€Š0.02). In a stepwise multivariate regression analysis, the variables significantly associated with IMT were minutes spent in hypoglycemia (r2ā€Š=ā€Š0.252; P<0.0001), and ISI index (r2ā€Š=ā€Š0.089; Pā€Š=ā€Š0.004), accounting for 34.1% of the variation. Episodes of hypoglycemia may be considered as a new potential cardiovascular risk factor for IGT individuals

    IAP Display: A Simple Method to Identify Mouse Strain Specific IAP Insertions

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    Intracisternal A-type particle (IAP) elements are high copy number long terminal repeat (LTR) rodent retrotransposons. Some IAP elements can transpose, and are responsible for ~12% of spontaneous mouse mutations. Inbred mouse strains show variation in genomic IAP distribution, contributing to inter-strain genetic variability. Additionally IAP elements can influence the transcriptional regulation of neighbouring genes through their strong LTR promoter, effecting phenotypic variation. This genetic and phenotypic variability can translate into experimental variability between mouse strains. For example, it has been demonstrated that strain-specific genetic/epigenetic factors can interact to yield variable responses to drugs. Therefore, in experimental contexts it is essential to unequivocally identify mouse strains. Recently it was estimated that any two inbred strains share only ~40% of their IAP insertions. Of the remaining 60%, some insertions will be strain specific, fixed during inbreeding. These fixed insertions can be exploited as genetic markers to identify inbred strains, if they can be identified simply and efficiently. Here, we report the development of a PCR-based system allowing direct acquisition of strain-specific IAP insertions. In a pilot study, we identified 21 IAP loci, genotyped IAP insertions at 9 loci, and discovered two strain-specific insertions that could reliably identify these strains

    Combined distributed turbo coding and space frequency block coding techniques

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    The distributed space-time (frequency) coding and distributed channel turbo coding used independently represent two cooperative techniques that can provide increased throughput and spectral efficiency at an imposed maximum Bit Error Rate (BER) and delay required from the new generation of cellular networks. This paper proposes two cooperative algorithms that employ jointly the two types of techniques, analyzes their BER and spectral efficiency performances versus the qualities of the channels involved, and presents some conclusions regarding the adaptive employment of these algorithms. Ā© 2010 V. Bota et al.FP7/ICT/2007/21547
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