We consider the transverse-momentum (
q
T
) distribution of generic high-mass systems (lepton pairs, vector bosons, Higgs particles, …) produced in hadron collisions. At small
q
T
, we concentrate on ...the all-order resummation of the logarithmically-enhanced contributions in QCD perturbation theory. We elaborate on the
b-space resummation formalism and introduce some novel features: the large logarithmic contributions are systematically exponentiated in a process-independent form and, after integration over
q
T
, they are constrained by perturbative unitarity to give a vanishing contribution to the total cross section. At intermediate and large
q
T
, resummation is consistently combined with fixed-order perturbative results, to obtain predictions with uniform theoretical accuracy over the entire range of transverse momenta. The formalism is applied to Standard Model Higgs boson production at LHC energies. We combine the most advanced perturbative information available at present for this process: resummation up to next-to-next-to-leading logarithmic accuracy and fixed-order perturbation theory up to next-to-leading order. The results show a high stability with respect to perturbative QCD uncertainties.
Objectives: The management of healthcare workers (HCWs) exposed to confirmed cases of coronavirus disease 2019 (COVID-19) is still a matter of debate. We aimed to assess in this group the attack rate ...of asymptomatic carriers and the symptoms most frequently associated with infection.
Occupational and clinical characteristics of HCWs who underwent nasopharyngeal swab testing for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a university hospital from 24 February 2020 to 31 March 2020 were collected. For those who tested positive and for those who tested positive but who were asymptomatic, we checked the laboratory and clinical data as of 22 May to calculate the time necessary for HCWs to then test negative and to verify whether symptoms developed thereafter. Frequencies of positive tests were compared according to selected variables using multivariable logistic regression models.
There were 139 positive tests (8.8%) among 1573 HCWs (95% confidence interval, 7.5–10.3), with a marked difference between symptomatic (122/503, 24.2%) and asymptomatic (17/1070, 1.6%) workers (p < 0.001). Physicians were the group with the highest frequency of positive tests (61/582, 10.5%), whereas clerical workers and technicians had the lowest frequency (5/137, 3.6%). The likelihood of testing positive for COVID-19 increased with the number of reported symptoms; the strongest predictors of test positivity were taste and smell alterations (odds ratio = 76.9) and fever (odds ratio = 9.12). The median time from first positive test to a negative test was 27 days (95% confidence interval, 24–30).
HCWs can be infected with SARS-CoV-2 without displaying any symptoms. Among symptomatic HCWs, the key symptoms to guide diagnosis are taste and smell alterations and fever. A median of almost 4 weeks is necessary before nasopharyngeal swab test results are negative.
Vbfnlo is a fully flexible parton level Monte Carlo program for the simulation of vector boson fusion, double and triple vector boson production in hadronic collisions at next-to-leading order in the ...strong coupling constant.
Vbfnlo includes Higgs and vector boson decays with full spin correlations and all off-shell effects. In addition,
Vbfnlo implements
CP
-even and
CP
-odd Higgs boson via gluon fusion, associated with two jets, at the leading-order one-loop level with the full top- and bottom-quark mass dependence in a generic two-Higgs-doublet model.
A variety of effects arising from beyond the Standard Model physics are implemented for selected processes. This includes anomalous couplings of Higgs and vector bosons and a Warped Higgsless extra dimension model. The program offers the possibility to generate Les Houches Accord event files for all processes available at leading order.
Program title:
Vbfnlo
Catalogue identifier: AEDO_v1_0
Program summary URL:
http://cpc.cs.qub.ac.uk/summaries/AEDO_v1_0.html
Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland
Licensing provisions: GPL version 2
No. of lines in distributed program, including test data, etc.: 339 218
No. of bytes in distributed program, including test data, etc.: 2 620 847
Distribution format: tar.gz
Programming language: Fortran, parts in C++
Computer: All
Operating system: Linux, should also work on other systems
Classification: 11.1, 11.2
External routines: Optionally Les Houches Accord PDF Interface library and the GNU Scientific library
Nature of problem: To resolve the large scale dependence inherent in leading order calculations and to quantify the cross section error induced by uncertainties in the determination of parton distribution functions, it is necessary to include NLO corrections. Moreover, whenever stringent cuts are required on decay products and/or identified jets the question arises whether the scale dependence and a k-factor, defined as the ratio of NLO to LO cross section, determined for the inclusive production cross sections are valid for the search region one is interested in.
Solution method: The problem is best addressed by implementing the one-loop QCD corrections in a fully flexible NLO parton-level Monte Carlo program, where arbitrary cuts can be specified as well as various scale choices. In addition, any currently available parton distribution function set can be used through the LHAPDF library.
Running time: Depending on the process studied. Usually from minutes to hours.
We consider the transverse-momentum (qT) distribution of Higgs bosons produced at hadron colliders. We use a formalism that uniformly treats both the small-qT and large-qT regions in QCD perturbation ...theory. At small qT (qT⪡MH, MH being the mass of the Higgs boson), we implement an all-order resummation of logarithmically-enhanced contributions up to next-to-next-to-leading logarithmic accuracy. At large qT (qT≳MH), we use fixed-order perturbation theory up to next-to-leading order. The resummed and fixed-order approaches are consistently matched by avoiding double-counting in the intermediate-qT region. In this region, the introduction of unjustified higher-order terms is avoided by imposing unitarity constraints, so that the integral of the qT spectrum exactly reproduces the perturbative result for the total cross section up to next-to-next-to-leading order. Numerical results at the LHC are presented. These show that the main features of the qT distribution are quite stable with respect to perturbative QCD uncertainties.
HIV persistence during combination antiretroviral therapy (cART) is the principal obstacle to cure. Mechanisms responsible for persistence remain uncertain; infections may be maintained by ...persistence and clonal expansion of infected cells or by ongoing replication in anatomic locations with poor antiretroviral penetration. These mechanisms require different strategies for eradication, and determining their contributions to HIV persistence is essential. We used phylogenetic approaches to investigate, at the DNA level, HIV populations in blood, lymphoid, and other infected tissues obtained at colonoscopy or autopsy in individuals who were on cART for 8 to 16 years. We found no evidence of ongoing replication or compartmentalization of HIV; we did detect clonal expansion of infected cells that were present before cART. Long-term persistence, and not ongoing replication, is primarily responsible for maintaining HIV. HIV-infected cells present when cART is initiated represent the only identifiable source of persistence and is the appropriate focus for eradication.
We present a computation of the O(αs) QCD corrections to W±Zγ production at the Large Hadron Collider. The photon is considered as real, and we include full leptonic decays for the W- and Z-bosons. ...Based on the structure of the VBFNLO program package, we obtain numerical results via a Monte Carlo program, which allows to implement general cuts and distributions of the final-state particles. The NLO QCD corrections are sizable and strongly exceed the theory error obtained by a scale variation of the leading-order result. Also, the shapes of relevant observables are significantly altered.
Objectives
The aim of this study was to evaluate the factors that can influence an incomplete viral response (IVR) after acute and early HIV infection (AEHI).
Methods
This was a retrospective, ...observational study including patients with AEHI (Fiebig stages I–V) diagnosed between January 2008 and December 2014 at 20 Italian centres. IVR was defined by: (1) viral blip (51–1000 HIV‐1 RNA copies/mL after achievement of < 50 HIV‐1 RNA copies/mL); (2) virologic failure > 1000 copies/mL after achievement of < 200 copies/mL, or ≥ 200 copies/mL after 24 weeks on an antiretroviral therapy (ART); (3) suboptimal viral response (> 50 copies/mL after 48 weeks on ART or two consecutive HIV‐1 RNA levels with ascending trend during ART). Cox regression analysis was used to calculate the hazard ratios (HRs) and 95% confidence intervals (95% CIs) for IVR.
Results
In all, 263 patients were studied, 227 (86%) males, with a median interquartile range (IQR) age of 38 (30–46) years. During a median follow‐up of 13.0 (5.7–31.1) months, 38 (14.4%) had IVR. The presence of central nervous system (CNS) symptoms was linked to a higher risk of IVR (HR = 4.70, 95% CI: 1.56–14.17), while a higher CD4/CD8 cell count ratio (HR = 0.13, 95% CI: 0.03–0.51 for each point increase) and first‐line ART with three‐drug regimens recommended by current guidelines (HR = 0.40, 95% CI: 0.18–0.91 compared with other regimens including four or five drugs, older drugs or non‐standard backbones) were protective against IVR.
Conclusions
Patients with lower CD4/CD8 ratio and CNS symptoms could be at a higher risk of IVR after AEHI. The use of recommended ART may be relevant for improving short‐term viral efficacy in this group of patients.
•Impact of BMI on long-term medical spending using twelve years of panel data.•First two-stage residual inclusion analysis of BMI on health spending.•New instrument in this setting: BMI of adult ...biological sibling in separate household.•Insurers pay $130 more annually per BMI unit, which is double the non-causal estimate.
While high body mass index (BMI) is believed to be a major driver of poor health, there is little evidence about whether it leads to higher health care spending. Understanding the causal contribution of BMI to health care spending is necessary to estimate the returns to investment in weight loss efforts. We exploit genetic variation in BMI across siblings as a natural experiment to estimate the impact of BMI on cumulative third party and out-of-pocket health care spending among adults using the Panel Study of Income Dynamics data from 1999 through 2011. We estimate a two-stage residual inclusion model with a generalized linear model. We find a $611.60 increase in cumulative insurer spending for each one-unit increase in BMI. This amounts to $130.49 in mean annual spending, and is two times higher than the non-causal estimate. We find no difference in out-of-pocket spending by BMI. These findings suggest that having a higher BMI in young/middle adulthood leads to significantly higher insurer health expenditures over the life course, which can help to inform public and private insurer policies on BMI reduction and control.
We calculate cross sections and asymmetries for slepton pair production through neutral and charged electroweak currents in polarized hadron collisions for general slepton masses and including mixing ...of the left- and right-handed interaction eigenstates relevant for third generation sleptons. Our analytical results confirm and extend a previous calculation. Numerically, we show that measurements of the longitudinal single-spin asymmetry at the existing polarized pp collider RHIC and at possible polarization upgrades of the Tevatron or the LHC would allow for a determination of the tau slepton mixing angle and/or the associated supersymmetry breaking parameters Λ for gauge mediation and A0 for minimal supergravity. Furthermore, the Standard Model background from tau pair production can be clearly distinguished due to the opposite sign of the associated asymmetry.
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