Multiple Interactions and the Structure of Beam Remnants

Recent experimental data have established some of the basic features of multiple interactions in hadron-hadron collisions. The emphasis is therefore now shifting, to one of exploring more detailed aspects. Starting from a brief review of the current situation, a next-generation model is developed, wherein a detailed account is given of correlated flavour, colour, longitudinal and transverse momentum distributions, encompassing both the partons initiating perturbative interactions and the partons left in the beam remnants. Some of the main features are illustrated for the Tevatron and the LHC.Comment: 69pp, 33 figure

SARS-CoV-2 infection among people living with HIV compared with people without HIV: Survey results from the MACS-WIHS combined cohort study

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) symptoms among people living with HIV (PLWH) are not well described. Setting: Longitudinal survey within the MACS/WIHS Combined Cohort Study (MWCCS) of PLWH compared with similar HIVseronegative (SN) individuals. Methods: Telephone-administered survey of MWCCS participants at 13 clinical research sites across the United States addressing COVID-19 symptoms, SARS-CoV-2 testing, and pandemic impact on social distancing and antiretroviral therapy (ART) use. Primary data collection occurred during May (wave 1), June-July (wave 2), and August-September, 2020 (wave 3). Results: One-third of MWCCS participants were tested for SARSCoV- 2 infection; 10% was tested ≥2 times. Similar proportions of PLWH and SN participants were tested, but SARS-CoV-2 positivity was higher among PLWH than among SN individuals (9.4% vs 4.8%, P = 0.003). Odds of SARS-CoV-2 positivity remained higher among PLWH after adjusting for age, sex, race/ethnicity, and study site (adjusted odds ratio = 2.0, 95% confidence interval = 1.2 to 3.2). SARS-CoV-2 positivity was not associated with CD4 cell counts among PLWH. Among SARS-CoV-2 positive participants, 9% had no symptoms, 7% had 1-2 mild symptoms, and 84% had ≥3 symptoms. Most of the (98%) participants reported physical distancing during all survey waves; self-reported ART adherence among PLWH was not adversely affected during the pandemic compared with the previous year (similar adherence in 89% of participants, improved in 9% of participants, and decreased in 2% of participants). Conclusions: Despite similar SARS-CoV-2 testing and physical distancing profiles by HIV serostatus among MWCCS participants, PLWH who reported SARS-CoV-2 testing were more likely to have a positive test result. Additional studies are needed to determine whether and why PLWH are at increased risk of SARS-CoV-2 infection

COVID-19 symptoms and SARS-CoV-2 infection among people living with HIV in the US: the MACS/WIHS combined cohort study

Background: SARS-CoV-2 infection among People Living With HIV (PLWH) is not well-described. Objective: To study COVID-19 symptoms and SARS-CoV-2 PCR-based swab testing among participants of the Multicenter AIDS Cohort Study (MACS) and Women’s Interagency HIV Study (WIHS). Methods: A telephone survey was collected April-June 30, 2020. Symptom and testing prevalence were explored. Multivariable logistic regression was used to examine the factors associated with SARS-CoV-2 positivity. Results: The survey was completed by 3411 participants, including 2078 (61%) PLWH and 1333 HIV-seronegative (SN) participants from across the US. Thirteen percent (n = 441) were tested for SARS-CoV-2 infection (13.4% of PLWH vs 12.2% of SN). Among those tested, positivity was higher in PLWH than SN (11.2% vs 6.1%, p = 0.08). Reasons for not being tested included testing not being available (30% of participants) and not knowing where to get tested (16% of participants). Most symptoms reported since January 2020 were similar in PLWH and SN, including headache (23% vs. 24%), myalgias (19% vs 18%), shortness of breath (14% vs 13%), chills (12% vs 10%), fever (6% vs 6%) and loss of taste or smell (6% vs 7%). Among PLWH who tested positive for SARS-CoV-2 DNA, the most common symptoms were headache (71%), myalgia (68%), cough (68%) and chills (65%). In multivariable analysis among those tested, the odds of SARS-CoV-2 positivity were higher among PLWH than SN (aOR = 2.22 95%CI = 01.01–4.85, p = 0.046) and among those living with others versus living alone (aOR = 2.95 95%CI = 1.18–7.40). Conclusion: Prevalence and type of COVID-19 symptoms were similar in PLWH and SN. SARS-CoV-2 infection may be elevated among PLWH

Menopause Is Associated with Immune Activation in Women with HIV

Background: Persistent immune activation due to gut barrier dysfunction is a suspected cause of morbidity in HIV, but the impact of menopause on this pathway is unknown. Methods: In 350 women with HIV from the Women's Interagency HIV Study, plasma biomarkers of gut barrier dysfunction (intestinal fatty acid binding protein; IFAB), innate immune activation (soluble CD14 and CD163; sCD14, sCD163), and systemic inflammation (interleukin-6 and tumor necrosis factor receptor 1; IL-6, TNFR1) were measured at 674 person-visits spanning ≤2 years. Results: Menopause (post-vs premenopausal status) was associated with higher plasma sCD14 and sCD163 in linear mixed-effects regression adjusting for age and other covariates (β=161.89 ng/mL; 95% confidence interval [CI], 18.37-305.41 and 65.48 ng/mL, 95% CI, 6.64-124.33, respectively); but not with plasma IFAB, IL-6, or TNFR1. In piece-wise linear mixed-effects regression of biomarkers on years before/after the final menstrual period, sCD14 increased during the menopausal transition by 250.71 ng/mL per year (95% CI, 16.63-484.79; P=.04), but not in premenopausal or postmenopausal periods. Conclusions: In women with HIV, menopause may increase innate immune activation, but data did not support an influence on the gut barrier or inflammation. Clinical implications of immune activation during menopausal transition warrant further investigation

Gauge invariant sub-structures of tree-level double-emission exact QCD spin amplitudes

In this note we discuss possible separations of exact, massive, tree-level spin amplitudes into gauge invariant parts. We concentrate our attention on processes involving two quarks entering a color- neutral current and, thanks to the QCD interactions, two extra external gluons. We will search for forms compatible with parton shower languages, without applying approximations or restrictions on phase space regions. Special emphasis will be put on the isolation of parts necessary for the construction of evolution kernels for individual splittings and to some degree for the running coupling constant as well. Our aim is to better understand the environment necessary to optimally match hard matrix elements with partons shower algorithms. To avoid complications and ambiguities related to regularization schemes, we ignore, at this point, virtual corrections. Our representation is quite universal: any color-neutral current can be used, in particular our approach is not restricted to vector currents only.Comment: 27 pages, formula in section 5 correcte

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Whole genome sequencing of Shigella sonnei through PulseNet Latin America and Caribbean: advancing global surveillance of foodborne illnesses

Objectives Shigella sonnei is a globally important diarrhoeal pathogen tracked through the surveillance network PulseNet Latin America and Caribbean (PNLA&C), which participates in PulseNet International. PNLA&C laboratories use common molecular techniques to track pathogens causing foodborne illness. We aimed to demonstrate the possibility and advantages of transitioning to whole genome sequencing (WGS) for surveillance within existing networks across a continent where S. sonnei is endemic. Methods We applied WGS to representative archive isolates of S. sonnei (n = 323) from laboratories in nine PNLA&C countries to generate a regional phylogenomic reference for S. sonnei and put this in the global context. We used this reference to contextualise 16 S. sonnei from three Argentinian outbreaks, using locally generated sequence data. Assembled genome sequences were used to predict antimicrobial resistance (AMR) phenotypes and identify AMR determinants. Results S. sonnei isolates clustered in five Latin American sublineages in the global phylogeny, with many (46%, 149 of 323) belonging to previously undescribed sublineages. Predicted multidrug resistance was common (77%, 249 of 323), and clinically relevant differences in AMR were found among sublineages. The regional overview showed that Argentinian outbreak isolates belonged to distinct sublineages and had different epidemiologic origins. Conclusions Latin America contains novel genetic diversity of S. sonnei that is relevant on a global scale and commonly exhibits multidrug resistance. Retrospective passive surveillance with WGS has utility for informing treatment, identifying regionally epidemic sublineages and providing a framework for interpretation of prospective, locally sequenced outbreaks

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society