1,431 research outputs found

    Simultaneous determination of <sup>210</sup>Pb and <sup>90</sup>Sr and <sup>210</sup>Po isolation in sludge samples using a plastic scintillation resin

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    This study describes a new and fast method for separating 210Po from 210Pb and 90Sr, before simultaneously measuring the individual activities of the latter two radionuclides using a plastic scintillation resin (PSresin) in sludge samples taken from a drinking water treatment plant. This method speeds up the analysis process significantly by simultaneously measuring 210Pb and 90Sr in a single step. The method is reproducible and has a relative standard deviation of less than 25% for 210Pb, 210Po and 90Sr. The method was satisfactorily validated with an intercomparison sample and applied to sludge samples from a drinking water treatment plant. The minimum detectable activities for 0.9 g of sludge are 5.5 Bq/kg and 8 Bq/kg for 210Pb and 90Sr respectively when measured for 180 min, and 0.5 Bq/kg for 210Po when measured for 5000 min

    Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory

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    Relevance of subclinical right ventricular dysfunction measured by feature-tracking cardiac magnetic resonance in non-ischemic dilated cardiomyopathy

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    Abstract Background Right ventricular (RV) dysfunction in patients with non-ischemic dilated cardiomyopathy (NICM) is associated with cardiovascular events. To analyze the feasibility of assessing RV myocardial deformation by feature tracking (FT)-cardiac magnetic resonance (CMR), and its usefulness as a prognostic marker. Methods Retrospective study of NICM patients undergoing CMR. Longitudinal FT-RV free wall (LFT-RVFW) and fractional area change (FAC) were obtained. Correlation with standard RV parameters was studied. An association with combined event (heart failure (HF), ICD implantation or cardiovascular death) was assessed using a logistic regression model. Results 98 patients (64‚ÄȬĪ‚ÄČ13¬†years) were included. Left ventricular (LV) systolic function (LVEF 29.5‚ÄȬĪ‚ÄČ9.6%, 47% with LVEF‚ÄČ‚Č•‚ÄČ30%) and RV (RVEF 52.2‚ÄȬĪ‚ÄČ14.6%, 72% with RVEF‚ÄČ‚Č•‚ÄČ45%). Follow-up of 38‚ÄȬĪ‚ÄČ17¬†months, 26.5% presented at least one admission for HF. An excellent correlation of LFT-RVFW (r‚ÄČ=‚ÄČ0.82) and FAC (r‚ÄČ=‚ÄČ0.83) with RVEF was evident. No association of RV-FT parameters with prognosis entire study population was found. However, in patients with LVEF‚ÄČ‚Č•‚ÄČ30%, admissions for HF were associated with lower LFT-RVFW (‚ąí21.6¬†¬Ī 6.6% vs ‚ąí31.3¬†¬Ī 10%; p = 0.006) and FAC (36.6¬†¬Ī 9.6% vs 50.5¬†¬Ī 13.4%; p < 0.001) values. Similar differences were observed when only patients with RVEF‚ÄČ‚Č•‚ÄČ45% were considered. An LFT-RVFW cut-off point of -19.5% and FAC of 36.5% showed good prognostic performance. Decreased LFT-RVFW or FAC represented an independent predictor of combined event in patients with LVEF‚ÄČ‚Č•‚ÄČ30%. Conclusions In NICM patients without severe LV dysfunction, decreased values of LFT-RVFW and/or FAC were associated with HF admissions, independently of RVEF

    Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

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    This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena

    The UHECR dipole and quadrupole in the latest data from the original Auger and TA surface detectors

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    The sources of ultra-high-energy cosmic rays are still unknown, but assuming standard physics, they are expected to lie within a few hundred megaparsecs from us. Indeed, over cosmological distances cosmic rays lose energy to interactions with background photons, at a rate depending on their mass number and energy and properties of photonuclear interactions and photon backgrounds. The universe is not homogeneous at such scales, hence the distribution of the arrival directions of cosmic rays is expected to reflect the inhomogeneities in the distribution of galaxies; the shorter the energy loss lengths, the stronger the expected anisotropies. Galactic and intergalactic magnetic fields can blur and distort the picture, but the magnitudes of the largest-scale anisotropies, namely the dipole and quadrupole moments, are the most robust to their effects. Measuring them with no bias regardless of any higher-order multipoles is not possible except with full-sky coverage. In this work, we achieve this in three energy ranges (approximately 8--16 EeV, 16--32 EeV, and 32--‚ąě EeV) by combining surface-detector data collected at the Pierre Auger Observatory until 2020 and at the Telescope Array (TA) until 2019, before the completion of the upgrades of the arrays with new scintillator detectors. We find that the full-sky coverage achieved by combining Auger and TA data reduces the uncertainties on the north-south components of the dipole and quadrupole in half compared to Auger-only results

    A Novel Tool for the Absolute End-to-End Calibration of Fluorescence Telescopes -The XY-Scanner

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    Radio Measurements of the Depth of Air-Shower Maximum at the Pierre Auger Observatory

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    International audienceThe Auger Engineering Radio Array (AERA), part of the Pierre Auger Observatory, is currently the largest array of radio antenna stations deployed for the detection of cosmic rays, spanning an area of 1717 km2^2 with 153 radio stations. It detects the radio emission of extensive air showers produced by cosmic rays in the 30‚ąí8030-80 MHz band. Here, we report the AERA measurements of the depth of the shower maximum (XmaxX_\text{max}), a probe for mass composition, at cosmic-ray energies between 1017.510^{17.5} to 1018.810^{18.8} eV, which show agreement with earlier measurements with the fluorescence technique at the Pierre Auger Observatory. We show advancements in the method for radio XmaxX_\text{max} reconstruction by comparison to dedicated sets of CORSIKA/CoREAS air-shower simulations, including steps of reconstruction-bias identification and correction, which is of particular importance for irregular or sparse radio arrays. Using the largest set of radio air-shower measurements to date, we show the radio XmaxX_\text{max} resolution as a function of energy, reaching a resolution better than 1515 g cm‚ąí2^{-2} at the highest energies, demonstrating that radio XmaxX_\text{max} measurements are competitive with the established high-precision fluorescence technique. In addition, we developed a procedure for performing an extensive data-driven study of systematic uncertainties, including the effects of acceptance bias, reconstruction bias, and the investigation of possible residual biases. These results have been cross-checked with air showers measured independently with both the radio and fluorescence techniques, a setup unique to the Pierre Auger Observatory

    Reproductive inequality in humans and other mammals

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    To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited degree of polygyny in the human societies that practice it, and to the importance of unequally held rival resources to women's fitness. The muted reproductive inequality observed in humans appears to be linked to several unusual characteristics of our species-including high levels of cooperation among males, high dependence on unequally held rival resources, complementarities between maternal and paternal investment, as well as social and legal institutions that enforce monogamous norms

    UHECR arrival directions in the latest data from the original Auger and TA surface detectors and nearby galaxies

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    The distribution of ultra-high-energy cosmic-ray arrival directions appears to be nearly isotropic except for a dipole moment of order 6√ó(E/10¬†EeV)6 \times (E/10~\mathrm{EeV}) per cent. Nonetheless, at the highest energies, as the number of possible candidate sources within the propagation horizon and the magnetic deflections both shrink, smaller-scale anisotropies might be expected to emerge. On the other hand, the flux suppression reduces the statistics available for searching for such anisotropies. In this work, we consider two different lists of candidate sources: a sample of nearby starburst galaxies and the 2MRS catalog tracing stellar mass within 250 Mpc. We combine surface-detector data collected at the Pierre Auger Observatory until 2020 and the Telescope Array until 2019, and use them to test models in which UHECRs comprise an isotropic background and a foreground originating from the candidate sources and randomly deflected by magnetic fields. The free parameters of these models are the energy threshold, the signal fraction, and the search angular scale. We find a correlation between the arrival directions of 11.8%‚ąí3.1%+5.0%11.8\%_{-3.1\%}^{+5.0\%} of cosmic rays detected with E‚Č•38¬†EeVE \ge 38~\mathrm{EeV} by Auger or with E‚Č≥49¬†EeVE \gtrsim 49~\mathrm{EeV} by TA and the position of nearby starburst galaxies on a 15.5‚ąė‚ąí3.2‚ąė+5.3‚ąė{15.5^\circ}_{-3.2^\circ}^{+5.3^\circ} angular scale, with a 4.2ŌÉ post-trial significance, as well as a weaker correlation with the overall galaxy distribution
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