Mendelian randomization implies no direct causal association between leukocyte telomere length and amyotrophic lateral sclerosis

We employed Mendelian randomization (MR) to evaluate the causal relationship between leukocyte telomere length (LTL) and amyotrophic lateral sclerosis (ALS) with summary statistics from genome-wide association studies (n = ~ 38,000 for LTL and ~ 81,000 for ALS in the European population; n = ~ 23,000 for LTL and ~ 4,100 for ALS in the Asian population). We further evaluated mediation roles of lipids in the pathway from LTL to ALS. The odds ratio per standard deviation decrease of LTL on ALS was 1.10 (95% CI 0.93–1.31, p = 0.274) in the European population and 0.75 (95% CI 0.53–1.07, p = 0.116) in the Asian population. This null association was also detected between LTL and frontotemporal dementia in the European population. However, we found that an indirect effect of LTL on ALS might be mediated by low density lipoprotein (LDL) or total cholesterol (TC) in the European population

Production of light-flavor hadrons in pp collisions at √s = 7 and √s = 13 TeV

The production of π±, K±, K0S, K∗(892)0, p, ϕ(1020), Λ, Ξ−, Ω−, and their antiparticles was measured in inelastic proton–proton (pp) collisions at a center-of-mass energy of s√ = 13 TeV at midrapidity (|y|<0.5) as a function of transverse momentum (pT) using the ALICE detector at the CERN LHC. Furthermore, the single-particle pT distributions of K0 S, , and in inelastic pp collisions at √s = 7 TeV are reported here for the first time. The pT distributions are studied at midrapidity within the transverse momentum range 0 ≤ pT ≤ 20 GeV/c, depending on the particle species. The pT spectra, integrated yields, and particle yield ratios are discussed as a function of collision energy and compared with measurements at lower √s and with results from various general-purpose QCD-inspired Monte Carlo models. A hardening of the spectra at high pT with increasing collision energy is observed, which is similar for all particle species under study. The transverse mass and xT ≡ 2pT/ √s scaling properties of hadron production are also studied. As the collision energy increases from √s = 7–13 TeV, the yields of non- and single-strange hadrons normalized to the pion yields remain approximately constant as a function of √s, while ratios for multi-strange hadrons indicate enhancements. The pT-differential cross sections of π±, K± and p (p) are compared with next-to-leading order perturbative QCD calculations, which are found to overestimate the cross sections for π± and p (p) at high pT

Production of light-flavor hadrons in pp collisions at √s = 7 and √s = 13 TeV

The production of π±, K±, K0S, K∗(892)0, p, ϕ(1020), Λ, Ξ−, Ω−, and their antiparticles was measured in inelastic proton–proton (pp) collisions at a center-of-mass energy of s√ = 13 TeV at midrapidity (|y|<0.5) as a function of transverse momentum (pT) using the ALICE detector at the CERN LHC. Furthermore, the single-particle pT distributions of K0S, Λ, and Λ¯¯¯¯ in inelastic pp collisions at s√=7 TeV are reported here for the first time. The pT distributions are studied at midrapidity within the transverse momentum range 0≤pT≤20 GeV/c, depending on the particle species. The pT spectra, integrated yields, and particle yield ratios are discussed as a function of collision energy and compared with measurements at lower s√ and with results from various general-purpose QCD-inspired Monte Carlo models. A hardening of the spectra at high pT with increasing collision energy is observed, which is similar for all particle species under study. The transverse mass and xT≡2pT/s√ scaling properties of hadron production are also studied. As the collision energy increases from s√ = 7–13 TeV, the yields of non- and single-strange hadrons normalized to the pion yields remain approximately constant as a function of s√, while ratios for multi-strange hadrons indicate enhancements. The pT-differential cross sections of π±, K± and p (p¯¯¯) are compared with next-to-leading order perturbative QCD calculations, which are found to overestimate the cross sections for π± and p (p¯¯¯) at high pT

Production of light-flavor hadrons in pp collisions at √s=7and√s=13TeV

The production of π±, K±, K0 S, K∗(892)0, p, φ(1020), , −, −, and their antiparticles was measured in inelastic proton–proton (pp) collisions at a center-of-mass energy of √s = 13 TeV at midrapidity (|y| < 0.5) as a function of transverse momentum (pT) using the ALICE detector at the CERN LHC. Furthermore, the single-particle pT distributions of K0 S, , and in inelastic pp collisions at √s = 7 TeV are reported here for the first time. The pT distributions are studied at midrapidity within the transverse momentum range 0 ≤ pT ≤ 20 GeV/c, depending on the particle species. The pT spectra, integrated yields, and particle yield ratios are discussed as a function of collision energy and compared with measurements at lower √s and with results from various general-purpose QCD-inspired Monte Carlo models. A hardening of the spectra at high pT with increasing collision energy is observed, which is similar for all particle species under study. The transverse mass and xT ≡ 2pT/ √s scaling properties of hadron production are also studied. As the collision energy increases from √s = 7–13 TeV, the yields of non- and single-strange hadrons normalized to the pion yields remain approximately constant as a function of √s, while ratios for multi-strange hadrons indicate enhancements. The pT-differential cross sections of π±, K± and p (p) are compared with next-to-leading order perturbative QCD calculations, which are found to overestimate the cross sections for π± and p (p) at high pT

Measurement of the production cross section of prompt Ξc0 baryons at midrapidity in pp collisions at √s = 5.02 TeV

The transverse momentum (pT) differential cross section of the charm-strange baryon Ξ0c is measured at midrapidity (|y| < 0.5) via its semileptonic decay into e+Ξ−νe in pp collisions at s√ = 5.02 TeV with the ALICE detector at the LHC. The ratio of the pT-differential Ξ0c-baryon and D0-meson production cross sections is also reported. The measurements are compared with simulations with different tunes of the PYTHIA 8 event generator, with predictions from a statistical hadronisation model (SHM) with a largely augmented set of charm-baryon states beyond the current lists of the Particle Data Group, and with models including hadronisation via quark coalescence. The pT-integrated cross section of prompt Ξ0c-baryon production at midrapidity is also reported, which is used to calculate the baryon-to-meson ratio Ξ0c/D0 = 0.20 ± 0.04 (stat.)+0.08−0.07 (syst.). These results provide an additional indication of a modification of the charm fragmentation from e+e− and e−p collisions to pp collisions

Λk femtoscopy in Pb-Pb collisions at sNN =2.76 TeV

The first measurements of the scattering parameters of K pairs in all three charge combinations (K+, K−, and K0 S ) are presented. The results are achieved through a femtoscopic analysis of K correlations in Pb-Pb collisions at √sNN = 2.76 TeV recorded by ALICE at the Large Hadron Collider. The femtoscopic correlations result from strong final-state interactions and are fit with a parametrization allowing for both the characterization of the pair emission source and the measurement of the scattering parameters for the particle pairs. Extensive studies with the THERMINATOR 2 event generator provide a good description of the nonfemtoscopic background, which results mainly from collective effects, with unprecedented precision. Furthermore, together with HIJING simulations, this model is used to account for contributions from residual correlations induced by feed-down from particle decays. The extracted scattering parameters indicate that the strong force is repulsive in the K+ interaction and attractive in the K− interaction. The data hint that the K0 S interaction is attractive; however, the uncertainty of the result does not permit such a decisive conclusion. The results suggest an effect arising either from different quark-antiquark interactions between the pairs (ss in K+ and uu in K−) or from different net strangeness for each system (S = 0 for K+, and S = −2 for K−). Finally, the K systems exhibit source radii larger than expected from extrapolation from identical particle femtoscopic studies. This effect is interpreted as resulting from the separation in space-time of the single-particle and K source distributions

Soft-Dielectron Excess in Proton-Proton Collisions at s =13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at √s=13 TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass mee and pair transverse momentum pT,ee that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of mee, pT,ee, and event multiplicity dNch/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π0 ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15 < mee < 0.6 GeV/c2 and for pT,ee < 0.4 GeV/c indicates an enhancement of soft dielectrons, reminiscent of the “anomalous” soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61 ± 0.13(stat) ± 0.17(syst, data) ± 0.34(syst, cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in mee and pT,ee are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.publishedVersio

Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at √sNN=5.02 TeV

The elliptic flow of electrons from beauty hadron decays at midrapidity ( | y | < 0.8 ) is measured in Pb-Pb collisions at √ s N N = 5.02     TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v 2 . The v 2 coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum ( p T ) range 1.3 – 6     GeV / c in the centrality class 30%–50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length c τ ≈ 500     μ m compared to that of charm hadrons and most of the other background sources. The v 2 of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75     σ . The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high p T , but is in agreement with the results at low p T . Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties

Λk femtoscopy in Pb-Pb collisions at sNN =2.76 TeV

The first measurements of the scattering parameters of ΛK pairs in all three charge combinations (ΛK+, ΛK−, and ΛK0S) are presented. The results are achieved through a femtoscopic analysis of ΛK correlations in Pb-Pb collisions at √sNN=2.76 TeV recorded by ALICE at the Large Hadron Collider. The femtoscopic correlations result from strong final-state interactions and are fit with a parametrization allowing for both the characterization of the pair emission source and the measurement of the scattering parameters for the particle pairs. Extensive studies with the THERMINATOR 2 event generator provide a good description of the nonfemtoscopic background, which results mainly from collective effects, with unprecedented precision. Furthermore, together with HIJING simulations, this model is used to account for contributions from residual correlations induced by feed-down from particle decays. The extracted scattering parameters indicate that the strong force is repulsive in the ΛK+ interaction and attractive in the ΛK− interaction. The data hint that the ΛK0S interaction is attractive; however, the uncertainty of the result does not permit such a decisive conclusion. The results suggest an effect arising either from different quark-antiquark interactions between the pairs (s¯s in ΛK+ and u¯u in ΛK−) or from different net strangeness for each system (S=0 for ΛK+, and S=−2 for ΛK−). Finally, the ΛK systems exhibit source radii larger than expected from extrapolation from identical particle femtoscopic studies. This effect is interpreted as resulting from the separation in space-time of the single-particle Λ and K source distributions

ΛK femtoscopy in Pb-Pb collisions at √sNN=2.76 TeV

The first measurements of the scattering parameters of K pairs in all three charge combinations (K+, K−, and K0 S ) are presented. The results are achieved through a femtoscopic analysis of K correlations in Pb-Pb collisions at √sNN = 2.76 TeV recorded by ALICE at the Large Hadron Collider. The femtoscopic correlations result from strong final-state interactions and are fit with a parametrization allowing for both the characterization of the pair emission source and the measurement of the scattering parameters for the particle pairs. Extensive studies with the THERMINATOR 2 event generator provide a good description of the nonfemtoscopic background, which results mainly from collective effects, with unprecedented precision. Furthermore, together with HIJING simulations, this model is used to account for contributions from residual correlations induced by feed-down from particle decays. The extracted scattering parameters indicate that the strong force is repulsive in the K+ interaction and attractive in the K− interaction. The data hint that the K0 S interaction is attractive; however, the uncertainty of the result does not permit such a decisive conclusion. The results suggest an effect arising either from different quark-antiquark interactions between the pairs (ss in K+ and uu in K−) or from different net strangeness for each system (S = 0 for K+, and S = −2 for K−). Finally, the K systems exhibit source radii larger than expected from extrapolation from identical particle femtoscopic studies. This effect is interpreted as resulting from the separation in space-time of the single-particle and K source distributions