Cross Section Measurements Research Articles

APOE4 impact on soluble and insoluble tau pathology is mostly influenced by amyloid-beta

Abstract The APOE4 allele is the strongest genetic risk factor for sporadic Alzheimer’s disease (AD). While APOE4 is strongly associated with amyloid-beta (Aβ), its relationship with tau accumulation is less understood. Studies evaluating the role of APOE4 on tau accumulation showed conflicting results, particularly regarding the independence of these associations from Aβ load. In this study, we examined three independent longitudinal cohorts (BioFINDER-1, BioFINDER-2 and WRAP) in which participants had cross-sectional and longitudinal measures of tau tangles (tau-PET; temporal meta-ROI and entorhinal) or soluble p-tau (p-tau217), Aβ-PET and APOE genotype. The study included a total of 1370 cognitively unimpaired (CU) and 449 mild cognitive impairment (MCI) subjects, followed longitudinally with tau-PET and p-tau217. APOE4 carriers accounted for 40.2-50% of the cohorts. Different linear regressions (cross-sectional) and linear mixed-effect models (longitudinal) with tau measures as outcomes were fitted to test the effect of APOE4 as independent predictor, as well as in combination with baseline Aβ load (including interaction). All models included age, sex and cognitive status as covariates. We found no independent effects of the APOE4 carriership on insoluble tau in either cohort (BioFINDER-2 or WRAP), both on cross-sectional and longitudinal tau-PET in the temporal meta-ROI, when Aβ was present in the model (p=0.531-0.949). Aβ alone was the best predictor of insoluble tau accumulation, with no interaction between APOE4 and Aβ on tau-PET. In BioFINDER-2, there was a significant interaction between APOE4 and Aβ (b=0.166, p<0.001) in the entorhinal cortex at baseline. However, the interaction was not present in WRAP PET. No independent effects of the APOE4 carriership on baseline (p=0.683-0.708) and longitudinal (p=0.188-0.570) soluble p-tau217 were observed when Aβ was included in the model in BioFINDER-1 and WRAP. Similarly, no interaction between APOE4 and Aβ on soluble p-tau217 was observed. Mediation analysis revealed that Aβ load fully mediated most associations between APOE4 and tau (46-112%, either cross-sectional or longitudinal tau-PET or soluble p-tau217). In the largest cohort (BioFINDER-2), looking at APOE4 groups by number of ε4 alleles, we found an interaction between APOE4 homozygotes and Aβ on tau-PET levels at baseline and over time in the temporal meta-ROI, while in the entorhinal cortex this effect was observed only at baseline. In conclusion, although APOE4 is strongly associated with Aβ aggregation, it seems to be minimally associated with longitudinal changes in soluble or insoluble p-tau levels at a given level of Aβ pathology, confirming the primacy of Aβ in driving tau pathology.

On the Ar I 419.8 nm/751.5 nm (3p5/2p5) line intensity ratio for electric field measurement in dielectric barrier discharge in argon at atmospheric pressure

Abstract Ar I 419.8 nm/751.5 nm line intensity ratio is suggested as a measure of the electric field in atmospheric pressure dielectric barrier discharges in argon. Using the electron distribution function calculated from the Boltzmann equation, electron impact excitation cross sections, quenching coefficients and other atomic data, theoretical dependencies of several line intensity ratios constructed from Ar I 3p5 4p and 3p5 5p argon lines on the electric field were calculated. Among them, the intensity ratio of 5p line at 419.8 nm (1s4–3p5 in Paschen notation) to 4p line at 751.5 nm line (1s4-2p5) was found to be sensitive in both the theory and the experiment.

The suggested line ratio was applied to the study of an atmospheric pressure volume dielectric barrier discharge in pure argon with sinusoidal voltage excitation. The spatiotemporal distribution of light emissions on 4p and 5p lines was measured using the time-correlated single photon counting technique (TCSPC) with high temporal (180 ps) and spatial (25 μm) resolution. The light emission on 419.8 nm line indicated the high electric field region in the propagating cathode-directed streamer due to a high excitation energy (14.58 eV) and a short effective lifetime (150 ps) of the 3p5 level. 

Several measured and calculated electron impact excitation cross sections were examined to interpret the measured line intensity ratio. Using the calculation based on a combination of the calculated (Zatsarinny 2014) and the measured cross section (Boffard 2007) for 2p5 and 3p5 levels, the electric field strengths reaching 110–120 Td were measured in the streamer head. 

The assumptions and limitations of this approach, as well as its instrumentation requirements, are discussed.

UHPLC-TIMS-PASEF®-MS for Lipidomics: From Theory to Practice.

Trapped ion mobility spectrometry (TIMS) using parallel accumulation serial fragmentation (PASEF®) is an advanced analytical technique that offers several advantages in mass spectrometry (MS)-based lipidomics. TIMS provides an additional dimension of separation to mass spectrometry and accurate collision cross-section (CCS) measurements for ions, aiding in the structural characterization of molecules. This is especially valuable in lipidomics for identifying and distinguishing isomeric or structurally similar compounds. On the other hand, PASEF technology allows for fast and efficient data acquisition by accumulating ions in parallel and then serially fragmenting them. This accelerates the analysis process and improves throughput, making it suitable for high-throughput applications. Moreover, the combination of TIMS and PASEF reduces co-elution and ion coalescence issues, leading to cleaner and more interpretable mass spectra. This results in higher data quality and more confident identifications. In this chapter, a data-dependent TIMS-PASEF® workflow for lipidomics analysis is presented.

Simultaneous Unbinned Differential Cross-Section Measurement of Twenty-Four Z+jets Kinematic Observables with the ATLAS Detector

Z boson events at the Large Hadron Collider can be selected with high purity and are sensitive to a diverse range of QCD phenomena. As a result, these events are often used to probe the nature of the strong force, improve Monte Carlo event generators, and search for deviations from standard model predictions. All previous measurements of Z boson production characterize the event properties using a small number of observables and present the results as differential cross sections in predetermined bins. In this analysis, a machine learning method called is used to produce a simultaneous measurement of twenty-four Z+jets observables using 139 fb−1 of proton-proton collisions at s=13 TeV collected with the ATLAS detector. Unlike any previous fiducial differential cross-section measurement, this result is presented unbinned as a dataset of particle-level events, allowing for flexible reuse in a variety of contexts and for new observables to be constructed from the twenty-four measured observables. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

The azimuthal correlation between the leading jet and the scattered lepton in deep inelastic scattering at HERA

The azimuthal correlation angle, Δϕ, between the scattered lepton and the leading jet in deep inelastic e±p scattering at HERA has been studied using data collected with the ZEUS detector at a centre-of-mass energy of s=318GeV, corresponding to an integrated luminosity of 326pb-1. A measurement of jet cross sections in the laboratory frame was made in a fiducial region corresponding to photon virtuality 10GeV2<Q2<350GeV2, inelasticity 0.04<y<0.7, outgoing lepton energy Ee>10GeV 10 {\\,\ ext {Ge}\\hspace{-0.66666pt}\ ext {V}}$$\\end{document}]]>, lepton polar angle 140∘<θe<180∘, jet transverse momentum 2.5GeV<pT,jet<30GeV, and jet pseudorapidity -1.5<ηjet<1.8. Jets were reconstructed using the kT algorithm with the radius parameter R=1. The leading jet in an event is defined as the jet that carries the highest pT,jet. Differential cross sections, dσ/dΔϕ, were measured as a function of the azimuthal correlation angle in various ranges of leading-jet transverse momentum, photon virtuality and jet multiplicity. Perturbative calculations at O(αs2) accuracy successfully describe the data within the fiducial region, although a lower level of agreement is observed near Δϕ→π for events with high jet multiplicity, due to limitations of the perturbative approach in describing soft phenomena in QCD. The data are equally well described by Monte Carlo predictions that supplement leading-order matrix elements with parton showering.

Assessment of peripheral nerve affection of the lower limbs in type 2 diabetic patients using neuromuscular ultrasound and electrodiagnostic studies

BackgroundDiabetic peripheral neuropathy is regarded as one of the most common microvascular sequalae of type 2 diabetes mellitus which leads to lower limb complications. Lately, the focus has shifted to early detection of diabetic neuropathy in the subclinical stage. While nerve conduction studies are considered non-invasive, sensitive and objective procedures for diagnosis of neuropathies, the missed diagnosis rate is high in early neuropathy. Recently, ultrasonography use has been regarded as an alternative method for detecting neuropathies, being an inexpensive and a more comfortable tool. The aim of this study was to define the pattern of affection of lower limb peripheral nerves in type 2 diabetic patients using neuromuscular ultrasound and to assess its utility in evaluation of diabetic peripheral neuropathy in asymptomatic diabetic patients.MethodsThis cross-sectional study included 40 type 2 diabetic patients and 20 healthy age- and sex-matched controls. All patients were subjected to full history taking, clinical examination, electrodiagnostic studies and neuromuscular ultrasound. Neuromuscular ultrasound was performed for tibial, fibular and sural nerves bilaterally for all patients and controls. Nerve cross-sectional area was measured at multiple sites for each nerve.ResultsDiabetic patients had statistically significant higher mean cross-sectional area values than controls in nearly all examined sites of all nerves. Furthermore, patients with electrophysiological diabetic peripheral neuropathy (EDPN) had higher statistically significant mean sural cross-sectional area values than patients without EDPN. There were no statistically significant differences in mean cross-sectional area values between symptomatic and asymptomatic patients with EDPN in all measured nerves. ROC analysis showed that sural nerve cross-sectional area cut off value of > 5 mm2 was predictive for diagnosis of EDPN.ConclusionsDiabetic cases, even asymptomatic ones, had statistically significant higher mean cross-sectional area values than controls on neuromuscular ultrasound. In addition, patients with EDPN showed higher cross-sectional area values of lower limbs peripheral nerves. Thus, neuromuscular ultrasound could be used as a screening tool for diabetic peripheral neuropathy using sural nerve cross-sectional area measurement at the ankle even in asymptomatic diabetic patients.

Production Cross-Section of γ-Rays from (p,p′γ) Reactions: Measurements and Theoretical Analysis

This paper reviews our work on the measurements of absolute production cross sections of γ-rays from the (p,p′γ) reactions on 12C and 16O. The measurements cover a range of 8–16 MeV for the incident proton beam. The angular distributions of the γ-rays have been measured. A detailed phenomenological analysis within the framework of optical model formalism has been carried out to reproduce the experimental data. The existing global set of elastic, polarization and total reaction data for protons and neutrons have been used to generate the optical model potential. The nuclear structure effects have been included in the calculations by considering the roles of coupling of the low-lying states, the presence of resonances and nuclear deformations. The potentials so generated have been used to calculate the differential and total cross sections for both (p,p′) and (p,p′γ) reactions. The results of the analysis are in good agreement with the measured data for the observed γ-rays. However, discrepancies still exist in reproducing the finer details of the cross sections. The existing discrepancies between our phenomenological analysis and the experimental data demonstrate the rather complex roles of channel couplings, resonances in the compound nuclear system and target deformation. The significant contribution of nuclear structure effects in light mass nucleus like 12C and 16O, leads to an apparent loss of predictive power of the theoretical calculation for low-energy region (less than 10 MeV) of the projectile energy.

Windowed anisotropic local inverse distance-weighted (WALID) interpolation method for riverbed mapping

AbstractDigital elevation models (DEMs) are pivotal in river engineering and management, making their accuracy paramount. This paper introduces a novel interpolation method that addresses the challenges of data point distributions, anisotropic river topography, and meandering rivers. The windowed anisotropic local inverse distance-weighted (WALID) method is tested and compared with conventional methods through a case study. Elevation data are generated from multi-beam echosounder data to mimic conventional cross-sectional measurements, while ground truth data provides qualitative comparisons. Root-mean-square error and volumetric differences are used as criteria for validation and comparison. Sensitivity analysis of the method’s free parameters demonstrated its robustness. Notably, the proposed algorithm exhibited superior volumetric accuracy compared to other methods when considering literature recommendations for optimal transect spacing.

Measurement of the Se78(n,γ)Se79 cross section up to 600 keV at the n_TOF facility at CERN

The Se78(n,γ)Se79 cross section has a high impact on the abundances of Se78 produced during the slow neutron capture process (s process) in massive stars. A measurement of the Se78 radiative neutron capture cross section has been performed at the Neutron Time-of-Flight facility at CERN using a set of liquid scintillation detectors that have been optimized for a low sensitivity to neutrons. We present resonance capture kernels up to 70 keV and cross section from 70 to 600 keV. Maxwellian-averaged cross section (MACS) values were calculated for stellar temperatures between kT=5 and 100 keV, with uncertainties between 4.6% and 5.8%. The new MACS values result in substantial decreases of 20–30% of Se78 abundances produced in the s process in massive stars and AGB stars. Massive stars are now predicted to produce subsolar Se78/Se76 ratios, which is expected since Se76 is an s-only isotope, while solar Se78 abundances have also contributions from other nucleosynthesis processes. Published by the American Physical Society 2024

Variational inference of effective range parameters for 3He−4He scattering

Abstract We use two different methods, Monte Carlo sampling and variational inference (VI), to perform a Bayesian calibration of the effective-range parameters in 3He–4He elastic scattering. The parameters are calibrated to data from a recent set of 3He–4He elastic scattering differential cross section measurements. Analysis of these data for E lab ≤ 4.3 MeV yields a unimodal posterior for which both methods obtain the same structure. However, the effective-range expansion amplitude does not account for the 7/2− state of 7Be so, even after calibration, the description of data at the upper end of this energy range is poor. The data up to E lab = 2.6 MeV can be well described, but calibration to this lower-energy subset of the data yields a bimodal posterior. After adapting VI to treat such a multi-modal posterior we find good agreement between the VI results and those obtained with parallel-tempered Monte Carlo sampling.

Electron‐Beam‐Induced Adatom‐Vacancy‐Complexes in Mono‐ and Bilayer Phosphorene

AbstractPhosphorene, a puckered 2D allotrope of phosphorus, has sparked considerable interest in recent years due to its potential especially for optoelectronic applications with its layer‐number‐dependant direct band gap and strongly bound excitons. However, detailed experimentalcharacterization of its intrinsic defects as well as its defect creation characteristics under electron irradiation are scarce. Here, the creation and stability of a variety of defect configurations under 60 kV electron irradiation in mono‐ and bilayer phosphorene are reported including the first experimental reports of stable adatom‐vacancy‐complexes. Displacement cross section measurements in bilayer phosphorene yield a value of 7.7 ± 1.4 barn with an estimated lifetime of adatom‐vacancy‐complexes of 19.9 ± 0.7 s, while some are stable for up to 68 s under continuous electron irradiation. Surprisingly, ab initio‐based simulations indicate that the complexes should readily recombine, even in structures strained by up to 3%. The presented results will help to improve the understanding of the wide variety of defects in phosphorene, their creation, and their stability, which may enable new pathways for defect engineered phosphorene devices.

Unveiling radii and neutron skins of unstable atomic nuclei via nuclear collisions

Total reaction, interaction, and charge-changing cross sections, which are kinds of cross sections standing for total nuclear collision probability in medium-to high-energy region from a few to several hundred MeV, have been extensively utilized to probe nuclear sizes especially for unstable nuclei. In this mini review, experimental techniques and recent findings from these cross sections are briefly overviewed. Additionally, two new methods to extract neutron skin thickness solely from the above cross sections are explained: One is utilizing the energy and isospin dependence of the total reaction cross sections, and the other is the combination of the total reaction and charge-changing cross section measurements.

Interference effects in differential cross sections for two-electron transfer

AbstractDifferential cross sections for simultaneous capture of both electrons by alpha particles from helium targets are computed. Employed are several quantum-mechanical distorted wave four-body methods of first- and second-orders. The main focus is on the cross section sensitivity as a function of different perturbation interactions and scattering states. Two aspects are considered. One is for theories with the same perturbation interactions and different scattering states. The other is for theories with the same scattering states and different perturbation interactions. In this context, the interference effect on two levels is examined. One compares the yields from the internuclear potential and the interactions between nuclei and two electrons. The other contrasts the contributions from the channel states with and without the distorted waves generated by the relative motions of nuclei. Depending on the employed theory, differential cross sections can be strongly or mildly influenced by the variability in all the mentioned frameworks. The salient illustrations are reported at intermediate energies 180-900 keV for which the experimental data are available. It is found that the second-order theories are in much better agreement with the measured cross sections than the first-order theories.

High-temperature measurements of acetylene VUV absorption cross sections and application to warm exoplanet atmospheres

Most observed exoplanets have high equilibrium temperatures (T$_ eq $ &gt; 500 K). Understanding the chemistry of their atmospheres and interpreting their observations requires the use of chemical kinetic models including photochemistry. The thermal dependence of the vacuum ultraviolet (VUV) absorption cross sections of molecules used in these models is poorly known at high temperatures, leading to uncertainties in the resulting abundance profiles. The aim of our work is to study experimentally the thermal dependence of VUV absorption cross sections of molecules of interest for exoplanet atmospheres and provide accurate data for use in atmospheric models. This study focuses on acetylene (C$_ $H$_ We measured absorption cross sections of C$_ $H$_ $ at seven temperatures ranging from 296 to 773 K recorded in the 115-230 nm spectral domain using VUV spectroscopy and synchrotron radiation. These data were used in our 1D thermo-photochemical model, to assess their impact on the predicted composition of a generic hot Jupiter-like exoplanet atmosphere. The absolute absorption cross sections of C$_ $H$_ $ increase with temperature. This increase is relatively constant from 115 to 185 nm and rises sharply from 185 to 230 nm. The abundance profile of C$_ $H$_ $ calculated using the model shows a slight variation, with a maximum decrease of 40&lt;!PCT!&gt; near 5 times 10$^ $ bar, when using C$_ $H$_ $ absorption cross sections measured at 773 K compared to those at 296 K. This is explained by the absorption, higher in the atmosphere, of the actinic flux from 150 to 230 nm due to the increase in the C$_ $H$_ $ absorption in this spectral range. This change also impacts the abundance profiles of other by-products such as methane (CH$_ $) and ethylene (C$_ $H$_ We present the first experimental measurements of the VUV absorption cross sections of C$_ $H$_ $ at high temperatures. Similar studies of other major species are needed to improve our understanding of exoplanet atmospheres.

Measurement of boosted Higgs bosons produced via vector boson fusion or gluon fusion in the H →bb¯ decay mode using LHC proton-proton collision data at s = 13 TeV

A measurement is performed of Higgs bosons produced with high transverse momentum (pT) via vector boson or gluon fusion in proton-proton collisions. The result is based on a data set with a center-of-mass energy of 13 TeV collected in 2016–2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb−1. The decay of a high-pT Higgs boson to a boosted bottom quark-antiquark pair is selected using large-radius jets and employing jet substructure and heavy-flavor taggers based on machine learning techniques. Independent regions targeting the vector boson and gluon fusion mechanisms are defined based on the topology of two quark-initiated jets with large pseudorapidity separation. The signal strengths for both processes are extracted simultaneously by performing a maximum likelihood fit to data in the large-radius jet mass distribution. The observed signal strengths relative to the standard model expectation are 4.9−1.6+1.9 and 1.6−1.5+1.7 for the vector boson and gluon fusion mechanisms, respectively. A differential cross section measurement is also reported in the simplified template cross section framework.

Recent Results from the FASER Experiment at the LHC

The ForwArd Search ExpeRiment (FASER), is an LHC experiment that aims to: (1) detect and study TeV-energy neutrinos, the most energetic neutrinos ever detected from a humanmade source and (2) search for new light and very weakly interacting particles. The FASER detector is located 480 m downstream of the ATLAS p-p interaction point, along the beam collision axis. FASER was designed, constructed, installed, and commissioned during 2019–2022 and has been taking physics data since the start of LHC Run 3 in July 2022. Recently, FASER reported the first measurement of ve and vμ interaction cross sections at the LHC with its sub-detector FASERv , FASER’s emulsion detector, first results on Axion-Like Particles at FASER and dark photons limits. These results will be reported in this article.

The Discovery of the Odderon by the D0 and TOTEM Collaborations

After a brief introduction of the odderon, we will describe its experimental discovery by the D0 and TOTEM collaborations by comparing pp and pp- elastic scattering data and by combining it with the ρ and total cross section measurements by the TOTEM collaboration.

Coupled channel analysis of neutron transfer in 6,7Li-induced reactions around the Coulomb barrier

Abstract The coupled reaction channel approach has proven to be quite effective in explaining the mechanism of nucleon transfer in heavy-ion reactions. Nevertheless, significant ambiguities remain regarding the selection of potential parameters and the states of the nuclei that should be coupled together for a specific reaction channel. Using the coupled reaction channel formalism, we have analyzed the excitation functions for one- and two-neutron transfer in 6,7Li-induced reactions on various targets. Spectroscopic amplitudes are taken from existing literature and shell model calculations. The one-neutron transfer cross sections from 6Li+93Nb and 7Li+115In reactions are reasonably well reproduced by coupled reaction channel calculations. A reasonable match for the measured cross sections was obtained for the two-neutron transfer in 7Li+181Ta reaction by employing the extreme cluster model.

Measurement of Neutron-Induced Single-Event Upset Cross Section of UltraScale Kintex FPGA Using Time-of-Flight Technique

Measurement of Neutron-Induced Single-Event Upset Cross Section of UltraScale Kintex FPGA Using Time-of-Flight Technique

Measurement of O2 and O3 absorption cross-sections in the 180–270 nm by controlling the conversion of O2 to O3 in the linear-absorption region

Measurement of O2 and O3 absorption cross-sections in the 180–270 nm by controlling the conversion of O2 to O3 in the linear-absorption region