4,029 research outputs found

    Higgs Boson Decay in the Large N Limit

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    The Equivalence Theorem is commonly used to calculate perturbatively amplitudes involving gauge bosons at energy scales higher than gauge boson masses. However, when the scalar sector is strongly interacting the theory is non-perturbative. We show that the Equivalence Theorem holds in the large N limit at next-to-leading order by calculating the decay widths h → W + W − and h → π + π − . We also show, in the same scheme of calculations, that unitarity is fulfilled for the process h → π + π −

    Intraoperative goal directed hemodynamic therapy in noncardiac surgery: a systematic review and meta-analysis

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    Background: The goal directed hemodynamic therapy is an approach focused on the use of cardiac output and related parameters as end-points for fluids and drugs to optimize tissue perfusion and oxygen delivery. Primary aim: To determine the effects of intraoperative goal directed hemodynamic therapy on postoperative complications rates. Methods: A meta-analysis was carried out of the effects of goal directed hemodynamic therapy in adult noncardiac surgery on postoperative complications and mortality using Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology. A systematic search was performed in Medline PubMed, Embase, and the Cochrane Library (last update, October 2014). Inclusion criteria were randomized clinical trials in which intraoperative goal directed hemodynamic therapy was compared to conventional fluid management in noncardiac surgery. Exclusion criteria were trauma and pediatric surgery studies and that using pulmonary artery catheter. End-points were postoperative complications (primary) and mortality (secondary). Those studies that fulfilled the entry criteria were examined in full and subjected to quantifiable analysis, predefined subgroup analysis (stratified by type of monitor, therapy, and hemodynamic goal), and predefined sensitivity analysis. Results: 51 RCTs were initially identified, 24 fulfilling the inclusion criteria. 5 randomized clinical trials were added by manual search, resulting in 29 randomized clinical trials in the final analysis, including 2654 patients. A significant reduction in complications for goal directed hemodynamic therapy was observed (RR: 0.70, 95% CI: 0.62-0.79, p < 0.001). No significant decrease in mortality was achieved (RR: 0.76, 95% CI: 0.45-1.28, p = 0.30). Quality sensitive analyses confirmed the main overall results. Conclusions: Intraoperative goal directed hemodynamic therapy with minimally invasive monitoring decreases postoperative complications in noncardiac surgery, although it was not able to show a significant decrease in mortality rate

    Pilot multicenter study to determine the utility of point-of-care ultrasound to predict difficulty of tracheal intubation using videolaryngoscopy with the McGrath™ Mac videolaryngoscope.

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    BACKGROUND Clinical airway screening tests used to predict difficulties during airway management have low sensitivity and specificity. Point-of-care airway ultrasound has described measurements related to problems with difficult direct laryngoscopy. Nevertheless, the correlation between ultrasound parameters and videolaryngoscopy has not been published yet. The aim of this multicenter, prospective observational pilot study was to evaluate the applicability of clinical parameters and ultrasound measurements to find potential tracheal intubation difficulties when videolaryngoscopy is used. METHODS Preoperatively, six clinical airway assessments were performed: (1) modified Mallampati score, (2) thyromental distance, (3) sternomental distance, (4) interincisal distance, (5) upper lip bite test, and (6) neck circumference. Six ultrasound parameters were measured in awake patients: (1) distance from skin to hyoid bone, (2) distance from skin to epiglottis, (3) hyomental distance in neutral head position, (4) hyomental distance in head-extended position, (5) distance from skin to the deepest part of the palate, and (6) sagittal tongue area. And finally, there was one ultrasound measure obtained in anesthetized patients, the compressed sagittal tongue area during videolaryngoscopy. The difficulty for tracheal intubation using a McGrath™ Mac videolaryngoscope, the percentage of glottic opening, and Cormack-Lehane grade were also assessed. RESULTS In this cohort of 119 subjects, tongue dimensions, particularly the sagittal tongue area, showed a robust association with increased intubation difficulty using videolaryngoscopy. A multiparametric model combining the following three ultrasound variables in awake patients: (a) the distance from skin to epiglottis, (b) the distance from skin to the deepest part of the palate, and (c) the sagittal tongue area, yielded a sensitivity of 92.3%, specificity of 94.5%, positive predictive value of 82.8%, and negative predictive value of 97.8% (p < 0.001). CONCLUSION Point-of-care airway ultrasound emerges as a more useful tool compared to traditional clinical scales to anticipate possible challenges during videolaryngoscopic intubation

    The alhambra survey: evolution of galaxy spectral segregation

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    We study the clustering of galaxies as a function of spectral type and redshift in the range 0.35 <z <1.1 using data from the Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The data cover 2.381 deg2 in 7 fields, after applying a detailed angular selection mask, with accurate photometric redshifts down to IAB <24. From this catalog we draw five fixed number density redshift-limited bins. We estimate the clustering evolution for two different spectral populations selected using the ALHAMBRA-based photometric templates: quiescent and star-forming galaxies. For each sample we measure the real-space clustering using the projected correlation function. Our calculations are performed over the range [0.03, 10.0] h-1 Mpc, allowing us to find a steeper trend for Mpc, which is especially clear for star-forming galaxies. Our analysis also shows a clear early differentiation in the clustering properties of both populations: star-forming galaxies show weaker clustering with evolution in the correlation length over the analyzed redshift range, while quiescent galaxies show stronger clustering already at high redshifts and no appreciable evolution. We also perform the bias calculation where similar segregation is found, but now it is among the quiescent galaxies where a growing evolution with redshift is clearer (abrigatted). These findings clearly corroborate the well-known color-density relation, confirming that quiescent galaxies are mainly located in dark matter halos that are more massive than those typically populated by star-forming galaxies.Ministerio de Economía y Competitividad y FEDER AYA2010-22111-C03-02 AYA2013-48623-C2-2 AYA2012-39620 AYA2013-40611-P AYA2013-42227-P AYA2013-43188-P AYA2013-48623-C2-1 ESP2013-48274 AYA2014-58861-C3-1Junta de Andalucía TIC114 JA2828 P10-FQM-644

    Autoantibodies against EPCR are found in antiphospholipid syndrome and are a risk factor for fetal death

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    The antiphospholipid syndrome (APS) is associated with thrombosis and fetal death but the pathologic mechanisms are poorly understood. Since endothelial protein C receptor (EPCR) plays a role in the anticoagulant system and in placental development, we hypothesized that anti-EPCR autoantibodies may be involved in clinical manifestations of APS and in fetal loss. The levels of immunoglobulin M (IgM) and IgG anti-EPCR autoantibodies were analyzed by enzyme-linked immunosorbent assay (ELISA) in 43 patients with APS and 43 controls. Anti-EPCR levels were higher in APS patients than in controls. Interestingly, one of the IgM anti-EPCR autoantibodies inhibited the generation of activated protein C on endothelium. Since markedly high anti-EPCR levels were found in women with fetal death, 87 patients with a first episode of unexplained fetal death were subsequently analyzed and their anti-EPCR levels were compared with 87 matched controls. We found that anti-EPCR autoantibodies constitute an independent risk factor for a first fetal death episode: the adjusted odds ratios (ORs) for anti-EPCR autoantibodies above the 95th percentile were 23.0 (95% confidence interval [CI], 2.0-266.3) for IgM and 6.8 (95% CI, 1.2-38.4) for IgG. Anti-EPCR autoantibodies can be detected in APS patients and are independent risk factors for fetal death

    Chemical composition, in vitro cytotoxic and antioxidant activities of the essential oil of Peruvian Minthostachys mollis Griseb

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    The composition of the essential oil obtained by hydrodistillation from Minthostachys mollis Griseb (Lamiaceae) aerial parts was determined by GC and GC/MS. Menthone (13.2%), pulegone (12.4%), cis-dihydrocarvone (9.8%) and carvacrol acetate (8.8%) were the main essential oil components. The cytotoxic activity of the essential oil was in vitro measured using the MTT colorimetric assay. IC50values were calculated on healthy non-tumor cells (HEK-293) and three human cancer cell lines (T24, DU-145 and MCF-7). In such latter cells, the estimated values were around 0.2 mg/mL. In addition, the antioxidant activity was determined by interaction with the stable freeradical 2,2”-diphenyl-1-picrylhydrazyl. The essential oil was almost devoid of antioxidant activity indicating that its anti-proliferative action relies on other unknown mechanism

    Direct Measurement of Nuclear Dependence of Charged Current Quasielastic-like Neutrino Interactions using MINERvA

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    Charged-current νμ\nu_{\mu} interactions on carbon, iron, and lead with a final state hadronic system of one or more protons with zero mesons are used to investigate the influence of the nuclear environment on quasielastic-like interactions. The transfered four-momentum squared to the target nucleus, Q2Q^2, is reconstructed based on the kinematics of the leading proton, and differential cross sections versus Q2Q^2 and the cross-section ratios of iron, lead and carbon to scintillator are measured for the first time in a single experiment. The measurements show a dependence on atomic number. While the quasielastic-like scattering on carbon is compatible with predictions, the trends exhibited by scattering on iron and lead favor a prediction with intranuclear rescattering of hadrons accounted for by a conventional particle cascade treatment. These measurements help discriminate between different models of both initial state nucleons and final state interactions used in the neutrino oscillation experiments
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