94 research outputs found

    Dark-Matter-Induced Weak Equivalence Principle Violation

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    A long-range fifth force coupled to dark matter can induce a coupling to ordinary matter if the dark matter interacts with Standard Model fields. We consider constraints on such a scenario from both astrophysical observations and laboratory experiments. We also examine the case where the dark matter is a weakly interacting massive particle, and derive relations between the coupling to dark matter and the coupling to ordinary matter for different models. Currently, this scenario is most tightly constrained by galactic dynamics, but improvements in Eotvos experiments can probe unconstrained regions of parameter space.Comment: 4 page

    Efficacy of Direct-Acting Antiviral Combination for Patients with Hepatitis C Virus Genotype 1 Infection and Severe Renal Impairment or End-Stage Renal Disease

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    © 2016 AGA Institute. Background & Aims Although hepatitis C virus (HCV) infection is common in patients with end-stage renal disease, highly efficacious, well-tolerated, direct-acting antiviral regimens have not been extensively studied in this population. We investigated the safety and efficacy of ombitasvir co-formulated with paritaprevir and ritonavir, administered with dasabuvir (with or without ribavirin) in a prospective study of patients with stage 4 or 5 chronic kidney disease (CKD). Methods We performed a single-arm, multicenter study of treatment-naïve adults with HCV genotype 1 infection, without cirrhosis and with CKD stage 4 (estimated glomerular filtration rate, 15-30 mL/min/1.73 m2) or stage 5 (estimated glomerular filtration rate, /min/1.73 m2or requiring hemodialysis). Twenty patients were given ombitasvir co-formulated with paritaprevir and ritonavir, administered with dasabuvir for 12 weeks. Patients with HCV genotype 1a infections also received ribavirin (n = 13), whereas those with genotype 1b infection did not (n = 7). The primary end point was sustained virologic response (serum HCV RNA /mL) 12 weeks after treatment ended (SVR12). We collected data on on-treatment adverse events (AEs), serious AEs, and laboratory abnormalities. Results All 20 patients completed 12 weeks of treatment. Eighteen of the 20 patients achieved SVR12 (90%; 95% confidence interval: 69.9-97.2). One patient death after the end of the treatment (unrelated to the treatment) and 1 relapse accounted for the 2 non-SVRs. Adverse events were primarily mild or moderate, and no patient discontinued treatment due to an AE. Four patients experienced serious AEs; all were considered unrelated to treatment. Ribavirin therapy was interrupted in 9 patients due to anemia; 4 received erythropoietin. No blood transfusions were performed. Conclusions In a clinical trial, the combination of ombitasvir, paritaprevir, and ritonavir, administered with dasabuvir, led to an SVR12 in 90% of patients with HCV genotype 1 infection and stage 4 or 5 CKD. The regimen is well tolerated, though RBV use may require a reduction or interruption to manage anemia. ClinicalTrials.gov ID NCT02207088

    Forward Jets and Energy Flow in Hadronic Collisions

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    We observe that at the Large Hadron Collider, using forward + central detectors, it becomes possible for the first time to carry out calorimetric measurements of the transverse energy flow due to "minijets" accompanying production of two jets separated by a large rapidity interval. We present parton-shower calculations of energy flow observables in a high-energy factorized Monte Carlo framework, designed to take into account QCD logarithmic corrections both in the large rapidity interval and in the hard transverse momentum. Considering events with a forward and a central jet, we examine the energy flow in the interjet region and in the region away from the jets. We discuss the role of these observables to analyze multiple parton collision effects.Comment: 9 pages, 5 figures. Version2: added results on azimuthal distributions and more discussion of energy flow definition using jet clusterin

    The prevalence and incidence of mental ill-health in adults with autism and intellectual disabilities

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    The prevalence, and incidence, of mental ill-health in adults with intellectual disabilities and autism were compared with the whole population with intellectual disabilities, and with controls, matched individually for age, gender, ability-level, and Down syndrome. Although the adults with autism had a higher point prevalence of problem behaviours compared with the whole adult population with intellectual disabilities, compared with individually matched controls there was no difference in prevalence, or incidence of either problem behaviours or other mental ill-health. Adults with autism who had problem behaviours were less likely to recover over a two-year period than were their matched controls. Apparent differences in rates of mental ill-health are accounted for by factors other than autism, including Down syndrome and ability level

    Strong Phases and Factorization for Color Suppressed Decays

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    We prove a factorization theorem in QCD for the color suppressed decays B0-> D0 M0 and B0-> D*0 M0 where M is a light meson. Both the color-suppressed and W-exchange/annihilation amplitudes contribute at lowest order in LambdaQCD/Q where Q={mb, mc, Epi}, so no power suppression of annihilation contributions is found. A new mechanism is given for generating non-perturbative strong phases in the factorization framework. Model independent predictions that follow from our results include the equality of the B0 -> D0 M0 and B0 -> D*0 M0 rates, and equality of non-perturbative strong phases between isospin amplitudes, delta(DM) = delta(D*M). Relations between amplitudes and phases for M=pi,rho are also derived. These results do not follow from large Nc factorization with heavy quark symmetry.Comment: 38 pages, 6 figs, typos correcte

    Nonfactorizable contributions to BD()MB \to D^{(*)} M decays

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    While the factorization assumption works well for many two-body nonleptonic BB meson decay modes, the recent measurement of BˉD()0M0\bar B\to D^{(*)0}M^0 with M=πM=\pi, ρ\rho and ω\omega shows large deviation from this assumption. We analyze the BD()MB\to D^{(*)}M decays in the perturbative QCD approach based on kTk_T factorization theorem, in which both factorizable and nonfactorizable contributions can be calculated in the same framework. Our predictions for the Bauer-Stech-Wirbel parameters, a2/a1=0.43±0.04|a_2/a_1|= 0.43\pm 0.04 and Arg(a2/a1)42Arg(a_2/a_1)\sim -42^\circ and a2/a1=0.47±0.05|a_2/a_1|= 0.47\pm 0.05 and Arg(a2/a1)41Arg(a_2/a_1)\sim -41^\circ, are consistent with the observed BDπB\to D\pi and BDπB\to D^*\pi branching ratios, respectively. It is found that the large magnitude a2|a_2| and the large relative phase between a2a_2 and a1a_1 come from color-suppressed nonfactorizable amplitudes. Our predictions for the Bˉ0D()0ρ0{\bar B}^0\to D^{(*)0}\rho^0, D()0ωD^{(*)0}\omega branching ratios can be confronted with future experimental data.Comment: 25 pages with Latex, axodraw.sty, 6 figures and 5 tables, Version published in PRD, Added new section 5 and reference

    Factorization and resummation of s-channel single top quark production

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    In this paper we study the factorization and resummation of s-channel single top quark production in the Standard Model at both the Tevatron and the LHC. We show that the production cross section in the threshold limit can be factorized into a convolution of hard function, soft function and jet function via soft-collinear-effective-theory (SCET), and resummation can be performed using renormalization group equation in the momentum space resummation formalism. We find that in general, the resummation effects enhance the Next-to-Leading-Order (NLO) cross sections by about 33%-5% at both the Tevatron and the LHC, and significantly reduce the factorization scale dependence of the total cross section at the Tevatron, while at the LHC we find that the factorization scale dependence has not been improved, compared with the NLO results.Comment: 29 pages, 7 figures; version published in JHE

    Factorization Theorem For Drell-Yan At Low q_T And Transverse-Momentum Distributions On-The-Light-Cone

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    We derive a factorization theorem for Drell-Yan process at low q_T using effective field theory methods. In this theorem all the obtained quantities are gauge invariant and the special role of the soft function--and its subtraction thereof--is emphasized. We define transverse-momentum dependent parton distribution functions (TMDPDFs) which are free from light-cone singularities while all the Wilson lines are defined on-the-light-cone. We show explicitly to first order in \alpha_s that the partonic Feynman PDF can be obtained from the newly defined partonic TMDPDF by integrating over the transverse momentum of the parton inside the hadron. We obtain a resummed expression for the TMDPDF, and hence for the cross section, in impact parameter space. The universality of the newly defined matrix elements is established perturbatively to first order in \alpha_s. The factorization theorem is validated to first order in \alpha_s and also the gauge invariance between Feynman and light-cone gauges.Comment: Minor changes. Version published in JHE

    ELEVATED PHENYLACETIC ACID LEVELS DO NOT CORRELATE WITH ADVERSE EVENTS IN PATIENTS WITH UREA CYCLE DISORDERS OR HEPATIC ENCEPHALOPATHY AND CAN BE PREDICTED BASED ON THE PLASMA PAA TO PAGN RATIO

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    Background Phenylacetic acid (PAA) is the active moiety in sodium phenylbutyrate (NaPBA) and glycerol phenylbutyrate (GPB, HPN-100), both are approved for treatment of urea cycle disorders (UCDs) - rare genetic disorders characterized by hyperammonemia. PAA is conjugated with glutamine in the liver to form phenylacetyleglutamine (PAGN), which is excreted in urine. PAA plasma levels ≥500 μg/dL have been reported to be associated with reversible neurological adverse events (AEs) in cancer patients receiving PAA intravenously. Therefore, we have investigated the relationship between PAA levels and neurological AEs in patients treated with these PAA pro-drugs as well as approaches to identifying patients most likely to experience high PAA levels. Methods The relationship between nervous system AEs, PAA levels and the ratio of plasma PAA to PAGN were examined in 4683 blood samples taken serially from: [1] healthy adults [2], UCD patients ≥2 months of age, and [3] patients with cirrhosis and hepatic encephalopathy (HE). The plasma ratio of PAA to PAGN was analyzed with respect to its utility in identifying patients at risk of high PAA values. Results Only 0.2% (11) of 4683 samples exceeded 500 ug/ml. There was no relationship between neurological AEs and PAA levels in UCD or HE patients, but transient AEs including headache and nausea that correlated with PAA levels were observed in healthy adults. Irrespective of population, a curvilinear relationship was observed between PAA levels and the plasma PAA:PAGN ratio, and a ratio > 2.5 (both in μg/mL) in a random blood draw identified patients at risk for PAA levels > 500 μg/ml. Conclusions The presence of a relationship between PAA levels and reversible AEs in healthy adults but not in UCD or HE patients may reflect intrinsic differences among the populations and/or metabolic adaptation with continued dosing. The plasma PAA:PAGN ratio is a functional measure of the rate of PAA metabolism and represents a useful dosing biomarker
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