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The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2–100 GeV/ c . The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types ( π , K, p) is achieved.

Mucosal IgA is key in preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Several mucosal vaccines are in development, and consistent methodologies assessing mucosal IgA are crucial for evaluation across clinical trials. We compared SARS-CoV-2 ancestral spike-specific IgA and secretory IgA (SIgA) in nasal secretions and saliva from 20 adults enrolled at Danderyd Hospital, Stockholm, Sweden, and 23 adults enrolled at the Icahn School of Medicine at Mount Sinai, New York, USA. Nasal secretions were collected by Nasosorption® and nasal swabs, and saliva by passive drooling, Salivette®, and saliva swabs. Antibody levels were measured in all samples using an electrochemiluminescence assay (ECL) and two enzyme-linked immunosorbent assays (ELISAs). Spike-specific IgA and SIgA levels measured by ECL correlated well with those measured by ELISA across nasal and saliva samples (range 0.42–0.94, p < 0.01), except for saliva collected by saliva swabs yielding lower IgA concentrations and weaker correlations (range − 0.21-0.27). Spike-specific IgA levels also correlated well across collection methods (range 0.7–0.9, p < 0.0001), with a weaker correlation between saliva collected by passive drooling and saliva swab (r = 0.55, p < 0.001). Although antibody levels correlated well between nasal secretions and saliva collected by passive drooling or Salivette® (range 0.64–0.86, p < 0.01), the overall levels were > 3-fold higher in nasal secretions compared to saliva (p < 0.01). This multi-center study demonstrates an overall good comparability between spike-specific IgA and SIgA across assays and collection methods, except for saliva swabs. Our findings suggest that nasal secretions may be preferable due to higher spike-specific IgA levels compared to in saliva.

Introduction The gold-standard sleep assessment technique, polysomnography (PSG), is impractical for use in many settings and populations (e.g., military) where objective sleep tracking is needed. Consumer-available sleep-tracking devices are being rapidly developed and, if validated, may be used to effectively track sleep in diverse settings and populations outside the laboratory or clinic. Therefore, we performed validation testing and comparison of wearable and non-wearable consumer sleep-tracking devices against PSG. Methods In an ongoing study, we tested 18 healthy participants (6 men and 12 women, 27.1±4.0 y; mean±SD) who slept 8 hours with PSG on 3 consecutive nights in a controlled sleep laboratory along with a set of consumer-available sleep-tracking devices. This included two wrist-worn devices (LifeTrak Brite R440, Fitbit Alta HR), an under-mattress device (EarlySense Live), and a bedside device (ResMed S+). Participants also wore a standard wrist actigraph for comparison (Philips Respironics Actiwatch-2). They maintained consistent 8-hour sleep schedules at home for 4 nights prior to the study and abstained from naps, caffeine, and alcohol. Epoch-by-epoch validation statistics of sensitivity (for sleep), specificity (for wakefulness), and Cohen’s kappa were calculated for each device and compared with PSG-scored sleep and wakefulness. Results Preliminary results for the device epoch-by-epoch measures of sensitivity, specificity, and Cohen’s kappa, respectively, were as follows: Actiwatch-2 (97.1%, 36.8%, 0.42), Brite R440 (98.5%, 28.3%, 0.36), Alta HR (94.3%, 46.2%, 0.42), Live (96.1%, 45.4%, 0.47), and S+ (93.3%, 50.0%, 0.44). Conclusion Overall, the consumer sleep-tracking devices we tested showed relatively high sensitivity but lower specificity, indicating a tendency for sleep devices to accurately detect sleep but to underdetect wakefulness. In this preliminary analysis, one wrist-worn device (Alta HR) and two non-wearable devices (Live and S+) showed the highest specificities, indicating these devices are promising for detection of wakefulness and comparable to standard wrist actigraphy. Further testing is needed to determine the validity and practicality for use of these consumer sleep-tracking devices within different settings and populations. Support (If Any) Office of Naval Research (ONR), Code 30

LHCb is a next-generation forward spectrometer for CP violation measurements, using the Large Hadron Collider at CERN. In order to achieve its goals a high overall track reconstruction performance is needed. The LHCb tracking system comprises three main sub-systems: the vertex locator, the trigger tracker and the downstream tracking stations.

This note investigates the effects of a misaligned tracking system on the analysis of B decays. Misalignment effects of both the vertex locator and the inner and outer T-stations have been studied. \\(z\\)-scaling effects of the vertex locator are also considered. It is proven that misalignments of the order of the detector single-hit resolutions have little or negligible effects on the quality of the reconstruction and of the analysis of B decays. The studies were performed with a sample of \\(B^0_{(s)} \\to h^+h^{'-}\\) decays, but the impact of misalignments on the performance of the pattern recognition algorithms and on the primary vertex resolutions, assessed for the first time, are rather general and not restricted to \\(B^0_{(s)} \\to h^+h^{'-}\\) decays.

The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2-100 GeV/c. The operation and control software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (pion, kaon and proton) is achieved.

A search for the decays Bs-->mumu and Bd-->mumu is performed with about 37 pb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are BR(Bs-->mumu) < 5.6 x 10^{-8} and BR(Bd-->mumu) <1.5 x 10^{-8} at 95% confidence level.

Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic \"van der Meer scan\" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.

The cross-section for inclusive phi meson production in pp collisions at a centre-of-mass energy of sqrt(s) = 7 TeV has been measured with the LHCb detector at the Large Hadron Collider. The differential cross-section is measured as a function of the phi transverse momentum p_T and rapidity y in the region 0.6 < p_T < 5.0 GeV/c and 2.44 < y < 4.06. The cross-section for inclusive phi production in this kinematic range is sigma(pp -> phi X) = 1758 pm 19(stat) ^{+43}_{-14}(syst) pm 182(scale) microbarn, where the first systematic uncertainty depends on the p_T and y region and the second is related to the overall scale. Predictions based on the Pythia 6.4 generator underestimate the cross-section.

The production of J/psi mesons in proton-proton collisions at sqrt(s)=7 TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/psi production is measured as a function of the J/psi transverse momentum pT and rapidity y in the fiducial region 0

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