94 research outputs found
Dark-Matter-Induced Weak Equivalence Principle Violation
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
© 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
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
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
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 decays
While the factorization assumption works well for many two-body nonleptonic
meson decay modes, the recent measurement of with
, and shows large deviation from this assumption. We
analyze the decays in the perturbative QCD approach based on
factorization theorem, in which both factorizable and nonfactorizable
contributions can be calculated in the same framework. Our predictions for the
Bauer-Stech-Wirbel parameters, and and and , are
consistent with the observed and branching ratios,
respectively. It is found that the large magnitude and the large
relative phase between and come from color-suppressed
nonfactorizable amplitudes. Our predictions for the , 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
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 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
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
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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