144 research outputs found
Nonperturbative contributions to a resummed leptonic angular distribution in inclusive boson production
We summarize a new analysis of the distribution of charged
leptons produced in decays of and bosons in the
Collins-Soper-Sterman (CSS) formalism for transverse momentum resummation. By
comparing the distribution measured at the Tevatron with the
resummed CSS cross section with approximate Wilson
coefficients, we constrain the magnitude of the nonperturbative Gaussian
smearing factor and analyze its uncertainty caused by variations in scale
parameters. We find excellent agreement between the data and
our theoretical prediction, provided by the \textsc{ResBos} resummation
program. The nonperturbative factor that we obtained can be used to update
resummed QCD predictions for precision measurements in inclusive and
production and for comparisons to various models of nonperturbative dynamics.Comment: 8 pages, 3 figures. Presented at conference: "The QCD Evolution
Workshop", May 14-17 2012, Thomas Jefferson National Accelerator Facility,
Newport News, V
Utility of MF-non coding region for measles molecular surveillance during post-elimination phase, Spain, 2017-2020
Background: In countries entering the post-elimination phase for measles, the study of variants by sequencing of 450 nucleotides of the N gene (N450) does not always allow the tracing of chains of transmission. Indeed, between 2017 and 2020, most measles virus sequences belonged to either the MVs/Dublin.IRL/8.16 (B3-Dublin) or the MVs/Gir Somnath.IND/42.16 (D8-Gir Somnath) variants. We evaluated the additional use of a non-coding region (MF-NCR) as a tool to enhance resolution and infer case origin, chains of transmission and characterize outbreaks. Methods: We obtained 115 high-quality MF-NCR sequences from strains collected from Spanish patients infected with either B3-Dublin or D8-Gir Somnath variants between 2017 and 2020, performed epidemiological, phylogenetic and phylodynamic analyses and applied a mathematical model to determine relatedness among identified clades. Results: Applying this model allowed us to identify phylogenetic clades potentially derived from concomitant importations of the virus rather than single chain of transmission, inferred based on only N450 and epidemiology data. In a third outbreak, we found two related clades that corresponded to two chains of transmission. Discussion: Our results show the ability of the proposed method to improve identification of simultaneous importations in the same region which could trigger enhanced contact tracing. Moreover, the identification of further transmission chains indicates that the size of import-related outbreaks was smaller than previously found, supporting the interpretation that endemic measles transmission was absent in Spain between 2017 and 2020. We suggest considering the use of the MF-NCR region in conjunction with the study of N450 variants in future WHO recommendations for measles surveillance.This work was supported by the “Instituto de Salud Carlos III” (PI15CIII/00023, PI19ICIII/0041). AG was funded by CIBER de Epidemiología y Salud Pública (CIBERESP), ISCIII. CJ was funded by the ECDC/EUPHEM fellowship.S
Gauge invariant definition of the jet quenching parameter
In the framework of Soft-Collinear Effective Theory, the jet quenching
parameter, , has been evaluated by adding the effect of Glauber gluon
interactions to the propagation of a highly-energetic collinear parton in a
medium. The result, which holds in covariant gauges, has been expressed in
terms of the expectation value of two Wilson lines stretching along the
direction of the four-momentum of the parton. In this paper, we show how that
expression can be generalized to an arbitrary gauge by the addition of
transverse Wilson lines. The transverse Wilson lines are explicitly computed by
resumming interactions of the parton with Glauber gluons that appear only in
non-covariant gauges. As an application of our result, we discuss the
contribution to coming from transverse momenta of order in a
medium that is a weakly-coupled quark-gluon plasma.Comment: 31 pages, 7 figures; journal versio
Characterization of methicillin-resistant Staphylococcus aureus strains colonizing the nostrils of Spanish children
Objective: To characterize the Staphylococcus aureus strains colonizing healthy Spanish children. Methods: Between March and July 2018, 1876 Spanish children younger than 14 years attending primary healthcare centers were recruited from rural and urban areas. Staphylococcus aureus colonization of the anterior nostrils was analyzed. MecA and mecC genes, antibiotic susceptibility, and genotyping according to the spa were determined in all strains, and the following toxins were examined: Panton-Valentine leucocidin (pvl), toxic shock syndrome toxin (tst), and exfoliative toxins (eta, etb, etd). Multilocus sequence typing (MLST) and staphylococcal cassette chromosome (SCCmec) typing were performed on methicillin-resistant Staphylococcus aureus (MRSA) strains, as well as pulsed-field gel electrophoresis (PFGE). Results: 619 strains were isolated in 1876 children (33%), and 92% of them were sent for characterization to the Spanish National Centre of Microbiology (n = 572). Twenty (3.5%) of these strains were mecA-positive. Several spa types were detected among MRSA, being t002 the most frequently observed (30%), associating with SCCmec IVc. Among MSSA, 33% were positive for tst, while only 0.73% were positive for pvl. The 20 MRSA strains were negative for pvl, and 6 (30%) harbored the tst gene. Conclusions: methicillin-resistant Staphylococcus aureus nasal colonization in Spanish children is rare, with t002 being the most observed spa type, associated with SCCmec IVc. None of the MRSA strains produced pvl, but up to 30% of S. aureus strains were positive for tst
European mitochondrial haplogroups predict liver-related outcomes in patients coinfected with HIV and HCV: a retrospective study
BACKGROUND: Mitochondrial DNA (mtDNA) haplogroups have been associated with advanced liver fibrosis and cirrhosis in patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). Our aim was to determine whether mtDNA haplogroups are associated with liver-related events (LREs) in HIV/HCV-coinfected patients. METHODS: We carried out a retrospective cohort study in HIV/HCV-coinfected patients who were potential candidates for therapy with interferon and ribavirin (IFN/Rib) between 2000 and 2009. The primary endpoint was the occurrence of LREs (decompensation or hepatocellular carcinoma). mtDNA genotyping was performed using the Sequenom MassARRAY platform. We used Fine and Gray proportional hazards model to test the association between mtDNA haplogroups and LREs, considering death as a competitive risk. RESULTS: The study population comprised 243 patients, of whom 40 had advanced fibrosis or cirrhosis. After a median follow-up of 7.7 years, 90 patients treated with IFN/Rib achieved sustained viral response (SVR), 18 patients had LREs, and 11 patients died. Patients with haplogroup H had lower cumulative incidence than patients with other haplogroups (p = 0.012). However, patients with haplogroup T had higher cumulative incidence than patients with other haplogroups (p = 0.074). In the multivariate analysis, haplogroup T was associated with an increased hazard of developing LREs [adjusted subhazard ratio (aSHR) = 3.56 (95% CI 1.13;11.30); p = 0.030]; whereas haplogroup H was not associated with lower hazard of LREs [aSHR = 0.36 (95% CI 0.10;1.25); p = 0.105]. When we excluded patients who achieved SVR during follow-up, we obtained similar SHR values. CONCLUSIONS: European mitochondrial haplogroups may influence the natural history of chronic hepatitis C.This study was supported by grants from Fondo de Investigación de Sanidad en España (Spanish Funds for Health Research [FIS]), grant numbers PI14/01094 and PI17/00657 to JB, PI14CIII/00011 and PI17CIII/00003 to SR. The study was also funded by the RD16CIII/0002/0002 and RD16/0025/0017 projects as part of the Plan Nacional R + D + I and cofunded by ISCIII- Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER). JB is an investigator from the Programa de Intensificación de la Actividad Investigadora en el Sistema Nacional de Salud (I3SNS), Refs INT15/00079 and INT16/00100. LMM, MAJS, and PGB are supported by “Instituto de Salud Carlos III” (grant numbers CD14/00002, CD13/00013, CP14/0010, and FI12/00036; respectively).S
Factorizing the hard and soft spectator scattering contributions for the nucleon form factor F_1 at large Q^2
We investigate the soft spectator scattering contribution for the FF .
We focus our attention on factorization of the hard-collinear scale corresponding to transition from SCET-I to SCET-II. We compute the
leading order jet functions and find that the convolution integrals over the
soft fractions are logarithmically divergent. This divergency is the
consequence of the boost invariance and does not depend on the model of the
soft correlation function describing the soft spectator quarks. Using as
example a two-loop diagram we demonstrated that such a divergency corresponds
to the overlap of the soft and collinear regions. As a result one obtains large
rapidity logarithm which must be included in the correct factorization
formalism. We conclude that a consistent description of the factorization for
implies the end-point collinear divergencies in the hard and soft
spectator contributions, i.e. convolution integrals with respect to collinear
fractions are not well-defined. Such scenario can only be realized when the
twist-3 nucleon distribution amplitude has specific end-point behavior which
differs from one expected from the evolution of the nucleon distribution
amplitude. Such behavior leads to the violation of the collinear factorization
for the hard spectator scattering contribution. We suggest that the soft
spectator scattering and chiral symmetry breaking provide the mechanism
responsible for the violation of collinear factorization in case of form factor
.Comment: 25 pages, 6 figures, text is improved, few typos corrected, one
figure added, statement about end-point behavior of the nucleon DA is
formulated more accuratel
Investigating Local Patterns of Mumps Virus Circulation, Using a Combination of Molecular Tools
Mumps is a vaccine-preventable disease caused by the mumps virus (MuV). However, MuV has re-emerged in many countries with high vaccine coverage. The World Health Organization (WHO) recommends molecular surveillance based on sequencing of the small hydrophobic (SH) gene. Additionally, the combined use of SH and non-coding regions (NCR) has been described in different studies, proving to be a useful complement marker to discriminate general patterns of circulation at national and international levels. The aim of this work is to test local-level usefulness of the combination of SH and MF-NCR sequencing in tracing hidden transmission clusters and chains during the last epidemic wave (2015-2020) in Spain. A database with 903 cases from the Autonomous Community of Madrid was generated by the integration of microbiological and epidemiological data. Of these, 453 representative cases were genotyped. Eight different SH variants and thirty-four SH haplotypes were detected. Local MuV circulation showed the same temporal pattern previously described at a national level. Only two of the thirteen previously identified outbreaks were caused by more than one variant/haplotype. Geographical representation of SH variants allowed the identification of several previously undetected clusters, which were analysed phylogenetically by the combination of SH and MF-NCR, in a total of 90 cases. MF-NCR was not able to improve the discrimination of geographical clusters based on SH sequencing, showing limited resolution for outbreak investigations.A.M.G. was funded by CIBER de Epidemiología y Salud Pública (CIBERESP), ISCIII. This work was supported by the “Instituto de Salud Carlos III” (PI15CIII/00023 and PI19ICIII/0041).S
Model Independent Evolution of Transverse Momentum Dependent Distribution Functions (TMDs) at NNLL
We discuss the evolution of the eight leading twist transverse momentum
dependent parton distribution functions, which turns out to be universal and
spin independent. By using the highest order perturbatively calculable
ingredients at our disposal, we perform the resummation of the large logarithms
that appear in the evolution kernel of transverse momentum distributions up to
next-to-next-to-leading logarithms (NNLL), thus obtaining an expression for the
kernel with highly reduced model dependence. Our results can also be obtained
using the standard CSS approach when a particular choice of the
prescription is used. In this sense, and while restricted to the perturbative
domain of applicability, we consider our results as a "prediction" of the
correct value of which is very close to . We
explore under which kinematical conditions the effects of the non-perturbative
region are negligible, and hence the evolution of transverse momentum
distributions can be applied in a model independent way. The application of the
kernel is illustrated by considering the unpolarized transverse momentum
dependent parton distribution function and the Sivers function.Comment: To appear in EPJC. 17 pages, 7 figure
Epidemiological and virological surveillance of mumps, Spain 2005-2022
Artículo[ES]Introducción: La parotiditis es una enfermedad frecuente, que sigue causando brotes incluso en poblaciones bien vacunadas. El objetivo de este estudio ha sido describir el patrón epidemiológico de la enfermedad y la calidad de la vigilancia de la parotiditis en España. Método: Fuentes: casos notificados a Red Nacional de Vigilancia Epidemiológica (RENAVE) entre 2005-2022 y resultados del programa de vigilancia microbiológica de parotiditis (PVMP) del Centro Nacional de Microbiología (CNM) entre 2016-2021. Se analizaron los casos por año, comunidad autónoma, sexo, edad, tipo de caso, vacunación e investigación de laboratorio. Se calcularon tasas anuales y de periodo. Del PVMP se analizaron muestras y determinaciones realizadas. Se analizó la cumplimentación de variables y la integración de la información de laboratorio en los casos notificados. Resultados: Se describen tres ondas epidémicas: 2005-2009, 2010-2014 y 2015-2020. La incidencia fue mínima en 2021 recuperándose ligeramente en 2022. La parotiditis afectó fundamentalmente a adolescentes y adultos jóvenes. El 32% de todos los casos estaban vacunados con dos dosis. Solo El 48% de los casos sospechosos investigados se confirmaron La saliva presentó la mayor tasa de positividad de PCR. La cumplimentación es adecuada para variables sociodemográficas, baja para la vacunación y muy baja para la gravedad. La información de laboratorio obtenida en el CNM en general no se notifica a RENAVE. Conclusiones: la parotiditis es una enfermedad frecuente que se debe monitorizar. Toda la información generada en actividades de vigilancia debe integrarse en un mismo sistema que sirva para la acción en salud pública. [EN] Introduction: mumps is a common disease, which continues to cause outbreaks even in well-vaccinat-ed vaccinated populations. The objective is to describe the surveillance of mumps in Spain. We present the analysis of cases reported to RENAVE (National epidemiological surveillance network) between 2005 and 2022 and the results of the mumps microbiological surveillance programme (PVMP) of the CNM (National Center of Microbiology) between 2016 and 2021. The completion of the variables and the integration of laboratory information in the reported cases are analysed.Method: Sources: cases reported to RENAVE and cases and samples from the CNM’s PVMP. Cases are analysed by year, autonomous community, sex and age, type of case, vaccination and laboratory data. Annual and period rates are calculated. Samples and determinations are analysed for PVMP.Results: Three epidemic waves are described: 2005-2009, 2010-2014 and 2015-2020. Incidence was minimal in 2021, recovering slightly in 2022. Mumps mainly affects adolescents and young adults. 32% of cases are vaccinated with two doses. Only 48% of investigated cases are confirmed. Saliva has the best PCR positivity rate. Completion is adequate for sociodemographic variables, low for vaccination and very low for severity. Information on laboratory studies performed in CNM is generally, not re-ported to RENAVE.Conclusions: Mumps is a common disease that should be monitored. All information generated in surveillance activities should be integrated into a single system devoted for public health action.N
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