744 research outputs found

    Liquid-gas phase transition in nuclear multifragmentation

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    The equation of state of nuclear matter suggests that at suitable beam energies the disassembling hot system formed in heavy ion collisions will pass through a liquid-gas coexistence region. Searching for the signatures of the phase transition has been a very important focal point of experimental endeavours in heavy ion collisions, in the last fifteen years. Simultaneously theoretical models have been developed to provide information about the equation of state and reaction mechanisms consistent with the experimental observables. This article is a review of this endeavour.Comment: 63 pages, 27 figures, submitted to Adv. Nucl. Phys. Some typos corrected, minor text change

    Recommendations for a core outcome set for measuring standing balance in adult populations: a consensus-based approach

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    Standing balance is imperative for mobility and avoiding falls. Use of an excessive number of standing balance measures has limited the synthesis of balance intervention data and hampered consistent clinical practice.To develop recommendations for a core outcome set (COS) of standing balance measures for research and practice among adults.A combination of scoping reviews, literature appraisal, anonymous voting and face-to-face meetings with fourteen invited experts from a range of disciplines with international recognition in balance measurement and falls prevention. Consensus was sought over three rounds using pre-established criteria.The scoping review identified 56 existing standing balance measures validated in adult populations with evidence of use in the past five years, and these were considered for inclusion in the COS.Fifteen measures were excluded after the first round of scoring and a further 36 after round two. Five measures were considered in round three. Two measures reached consensus for recommendation, and the expert panel recommended that at a minimum, either the Berg Balance Scale or Mini Balance Evaluation Systems Test be used when measuring standing balance in adult populations.Inclusion of two measures in the COS may increase the feasibility of potential uptake, but poses challenges for data synthesis. Adoption of the standing balance COS does not constitute a comprehensive balance assessment for any population, and users should include additional validated measures as appropriate.The absence of a gold standard for measuring standing balance has contributed to the proliferation of outcome measures. These recommendations represent an important first step towards greater standardization in the assessment and measurement of this critical skill and will inform clinical research and practice internationally

    Ethnic differences in urinary calcium and phosphate excretion between Gambian and British older adults

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    Summary: Ethnic differences in renal calcium and phosphate excretion exist, which may depend on differences in their dietary intakes and regulatory factors. We report highly significant differences in urinary calcium and phosphate excretion between white British and Gambian adults after statistical adjustment for mineral intakes, indicating an independent effect of ethnicity.  Introduction: Populations vary in their risk of age-related osteoporosis. There are racial or ethnic differences in the metabolism of the bone-forming minerals calcium (Ca) and phosphate (P), with a lower renal Ca and P excretion in African-Americans compared to white counterparts, even at similar intakes and rates of absorption. Also, Africans in The Gambia have a lower Ca excretion compared to white British subjects, groups known to differ in their dietary Ca intake. Here, we report on differences in urinary Ca and P excretion between Gambian and white British adults while allowing for known predictors, including dietary intakes.  Methods: Participants were healthy white British (n = 60) and Gambian (n = 61) men and women aged 60–75 years. Fasting blood and 2-h urine samples were collected. Markers of Ca and P metabolism were analysed. Dietary intake was assessed with country-specific methods.  Results: White British older adults had higher creatinine-corrected urinary Ca and P excretion (uCa/uCr, uP/uCr) and lower tubular maximum of Ca and P compared to Gambian counterparts. The predictors of urinary Ca and P differed between groups. Multiple regression analysis showed that dietary Ca and Ca/P were predictors of uCa/uCr and uP/uCr, respectively. Ethnicity remained a significant predictor of uCa/uCr and uP/uCr after adjustment for diet and other factors.  Conclusions: Gambian older adults have higher renal Ca conservation than British counterparts. Dietary mineral intakes were predictors of the differences in urinary Ca and P excretion, but ethnicity remained a highly significant predictor after statistical adjustment. This suggests that ethnicity has an independent effect on renal Ca and P handling

    Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

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    Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

    Quantum Measurement Theory in Gravitational-Wave Detectors

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    The fast progress in improving the sensitivity of the gravitational-wave (GW) detectors, we all have witnessed in the recent years, has propelled the scientific community to the point, when quantum behaviour of such immense measurement devices as kilometer-long interferometers starts to matter. The time, when their sensitivity will be mainly limited by the quantum noise of light is round the corner, and finding the ways to reduce it will become a necessity. Therefore, the primary goal we pursued in this review was to familiarize a broad spectrum of readers with the theory of quantum measurements in the very form it finds application in the area of gravitational-wave detection. We focus on how quantum noise arises in gravitational-wave interferometers and what limitations it imposes on the achievable sensitivity. We start from the very basic concepts and gradually advance to the general linear quantum measurement theory and its application to the calculation of quantum noise in the contemporary and planned interferometric detectors of gravitational radiation of the first and second generation. Special attention is paid to the concept of Standard Quantum Limit and the methods of its surmounting.Comment: 147 pages, 46 figures, 1 table. Published in Living Reviews in Relativit

    Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

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    The azimuthal anisotropy of charged particles in PbPb collisions at nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pt) range up to approximately 60 GeV. The data cover both the low-pt region associated with hydrodynamic flow phenomena and the high-pt region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0-60% most-central events, the observed v2 values are found to first increase with pt, reaching a maximum around pt = 3 GeV, and then to gradually decrease to almost zero, with the decline persisting up to at least pt = 40 GeV over the full centrality range measured.Comment: Replaced with published version. Added journal reference and DO

    Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy

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    A search for new physics is performed in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state. The analysis is based on a data sample corresponding to an integrated luminosity of 4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of 140 increase in integrated luminosity over previously published results. The observed yields agree with the standard model predictions and thus no evidence for new physics is found. The observations are used to set upper limits on possible new physics contributions and to constrain supersymmetric models. To facilitate the interpretation of the data in a broader range of new physics scenarios, information on the event selection, detector response, and efficiencies is provided.Comment: Published in Physical Review Letter

    Prognostic factors in solitary plasmacytoma of the bone: a multicenter Rare Cancer Network study

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    BACKGROUND: Solitary plasmacytoma (SP) of the bone is a rare plasma-cell neoplasm. There are no conclusive data in the literature on the optimal radiation therapy (RT) dose in SP. Therefore, in this large retrospective study, we wanted to assess the outcome, prognostic factors, and the optimal RT dose in patients with SP. METHODS: Data from 206 patients with bone SP without evidence of multiple myeloma (MM) were collected. Histopathological diagnosis was obtained for all patients. The majority (n = 169) of the patients received RT alone; 32 chemotherapy and RT, and 5 surgery. Median follow-up was 54 months (7–245). RESULTS: Five-year overall survival, disease-free survival (DFS), and local control was 70%, 46%, and 88%; respectively. Median time to MM development was 21 months (2–135) with a 5-year probability of 51%. In multivariate analyses, favorable factors were younger age and tumor size < 5 cm for survival; younger age for DFS; anatomic localization (vertebra vs. other) for local control. Older age was the only predictor for MM. There was no dose-response relationship for doses 30 Gy or higher, even for larger tumors. CONCLUSION: Younger patients, especially those with vertebral localization have the best outcome when treated with moderate-dose RT. Progression to MM remains the main problem. Further investigation should focus on adjuvant chemotherapy and/or novel therapeutic agents

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    P73 regulates cisplatin-induced apoptosis in ovarian cancer cells via a calcium/calpain-dependent mechanism

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    P73 is important in drug-induced apoptosis in some cancer cells, yet its role in the regulation of chemosensitivity in ovarian cancer (OVCA) is poorly understood. Furthermore, if and how the deregulation of p73-mediated apoptosis confers resistance to cisplatin (CDDP) treatment is unclear. Here we demonstrate that TAp73α over-expression enhanced CDDP-induced PARP cleavage and apoptosis in both chemosensitive (OV2008 and A2780s) and their resistant counterparts (C13* and A2780cp) and another chemoresistant OVCA cells (Hey); in contrast, the effect of ΔNp73α over-expression was variable. P73α downregulation attenuated CDDP-induced PUMA and NOXA upregulation and apoptosis in OV2008 cells. CDDP decreased p73α steady-state protein levels in OV2008, but not in C13*, although the mRNA expression was identical. CDDP-induced p73α downregulation was mediated by a calpain-dependent pathway. CDDP induced calpain activation and enhanced its cytoplasmic interaction and co-localization with p73α in OV2008, but not C13* cells. CDDP increased the intracellular calcium concentration ([Ca2+]i) in OV2008 but not C13* whereas cyclopiazonic acid (CPA), a Ca2+-ATPase inhibitor, caused this response and calpain activation, p73α processing and apoptosis in both cell types. CDDP-induced [Ca2+]i increase in OV2008 cells was not effected by the elimination of extracellular Ca2+, but this was attenuated by the depletion of internal Ca2+ store, indicating that mobilization of intracellular Ca2+] stores was potentially involved. These findings demonstrate that p73α and its regulation by the Ca2+-mediated calpain pathway are involved in CDDP-induced apoptosis in OVCA cells and that dysregulation of Ca2+/calpain/p73 signaling may in part be the pathophysiology of CDDP resistance. Understanding the cellular and molecular mechanisms of chemoresistance will direct the development of effective strategies for the treatment of chemoresistant OVCA
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