Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at √sNN = 5.02 TeV with the LHCb detector

Flow harmonic coefficients, v n , which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02 TeV . The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features

Helium identification with LHCb

The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at √(s) = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb-1. A total of around 105 helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10^12). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei

Curvature-bias corrections using a pseudomass method

Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using Z→μ + μ - decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z→μ + μ - mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass

Unveiling melanomagenesis through the dermatoscope

Linked article: O. Reiter et al. J Eur Acad Dermatol Venereol 2021; 35: 1111–1118. https://doi.org/10.1111/jdv.17133

Scaling relationships of source parameters of Mw 6.9-8.1 earthquakes in the cocos-rivera-north american subduction zone

Seven slip models currently available from kinematic inversions, derived from near-source strong-motion and teleseismic body waves in the 0-1.25 Hz frequency range from Mexico's subduction zone, are used to estimate source-scaling relationships applicable to the region. Our results are compared with existing scaling relations for subduction environments. The relationships for the rupture area of our results are closer to those of Somerville et al. (2002) than to any other, but, like the others, they have smaller areas than predicted by Somerville et al. (2002). Concerning the combined area of asperities, Murotani et al. (2008) and our results predict smaller areas than those obtained by Somerville et al. (2002). Concerning the area of largest asperity, the relationships obtained in this study are slightly smaller than those described by Somerville et al. (2002); this is a consistent result with the relationships of total rupture area and combined area of asperities. In general, the error estimates for the constrained equations derived in this study in all cases are smaller than those relationships compared here. This might suggest that the expressions obtained in this study could be appropriate for the simulations of strong ground motion for a specific scenario of earthquake slip in the region. Also, these results could be an indication that the relationships vary depending on a specific subduction tectonic region. On the other hand, Aguirre and Irikura (2007) estimated the source area for 31 Mexican earthquakes using corner frequencies; these areas show close resemblance with those predicted by the relationships derived in this study. Based on these findings, an important implication is that two different methodologies to determine the total area of asperities based on either low- or high-frequency data generate similar results

Coherence enhancement in coupled chaotic neurons

Through numerical simulations and electronic experiments we demonstrate the improved regularity in inter-spike intervals of a chaotic Hindmarsh-Rose neuron affected by another chaotic neuron

Association between the dermoscopic morphology of peripheral globules and melanocytic lesion diagnosis

Background The presence of peripheral globules is associated with enlarging melanocytic lesions; however, there are numerous patterns of peripheral globules distribution and it remains unknown whether specific patterns can help differentiate enlarging naevi from melanoma. Objective To investigate whether morphological differences exist between the peripheral globules seen in different subsets of naevi and in melanoma. Methods A cross‐sectional study of clinical notes that mentioned peripheral globules, in addition to all melanoma images with peripheral globules on the International Skin Imaging Collaboration archive. Dermoscopic images were reviewed and annotated. Associations between diagnosis and categorical features were measured with odds ratios. Non‐parametric tests were used for continuous factors. Results 184 lesions with peripheral globules from our clinic were included in the analysis; only 6 of these proved to be melanoma. 109 melanomas with peripheral globules from the International Skin Imaging Collaboration archive were added to the analysis. Melanomas were more common on the extremities and among older individuals. Melanomas were more likely to display atypical, tiered and/or focal peripheral globules. Only 5% of melanomas lacked dermoscopic melanoma‐specific structures compared to 48% of naevi. Conclusions Melanocytic lesions with atypical or asymmetrically distributed peripheral globules, especially when located on the extremities, should raise suspicion for malignancy. Melanocytic lesions with typical and symmetrically distributed peripheral globules, and with no other concerning dermoscopic features, are unlikely to be malignant

Validez del exceso de bases como factor pronóstico de mortalidad en pacientes traumatizados

5 páginasBackground: Base excess is used to determine the mag-nitude of metabolic abnormality secondary to hemorrhage or direct organ damage of patients with polytrauma Objective: To determine what are the values of change that BE can have over time and that allow predicting early mortality in patients with polytrauma. Methods: Retrospective cohort study in subjects older than 18 years, who were admitted to the intensive care unit for any type of trauma. The response to the change of the base excess at 6, 12 and 24 hours after the trauma was evaluated. Results: 261 subjects were included, 22.6% (59/261) died. Polytrauma occurred in 73.2% (191/261) and traf-fic accident was the most common mechanism of trauma in the study population with 75.9%. The change in BE between admission and the first 6 hours was 1.7 mEq/L (SD: 4.02) in the living population and 1.9 mEq/L (SD: 8.1) in the deceased (p<0.001). The change in mEq/L between admission and first 6 hours showed a low receiver operat-ing characteristics curve area of 0.661 (95% CI: 0.523-0.8; p=0.025). Conclusión: The change in base excess between the first 6 to 12 hours after patient admission can be used to esti-mate mortality in patients diagnosed with trauma. © 2023, Venezuelan Society of Pharmacology and Clinical and Therapeutic Pharmacology. All rights reserved