681 research outputs found

    Azimuthal correlation in DIS

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    We introduce the azimuthal correlation for the deep inelastic scattering process. We present the QCD prediction to the level of next-to-leading log resummation, matching to the fixed order prediction. We also estimate the leading non-perturbative power correction. The observable is compared with the energy-energy correlation in e+e- annihilation, on which it is modelled. The effects of the resummation and of the leading power correction are both quite large. It would therefore be particularly instructive to study this observable experimentally.Comment: 33 pages, 4 figures, JHEP class included. One figure and some clarifications adde

    Assessing the survival of carbonaceous chondrites impacting the lunar surface as a potential resource

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    The Moon offers a wide range of potential resources that may help sustain a future human presence, but it lacks indigenous carbon (C) and nitrogen (N). Fortunately, these elements will have been delivered to the Moon’s surface by carbonaceous chondrite (CC) asteroid impactors. Here, we employ numerical modelling to assess the extent to which these materials may have sufficiently survived impact with the lunar surface to be viable sources of raw materials for future exploration. We modelled the impact of a 1 km diameter CC-like asteroid, considering impact velocities between 5 and 15 km/s, and impact angles between 15 and 60◦ to the horizontal. The most favourable conditions for the survival of C-rich, and especially N-rich materials, are those with the lowest impact velocities (≤10 km/s) and impact angles (≤15◦). Impacts with velocities >10 km/s and angles >30◦ were found not to yield any significant amount of surviving solid material, where bulk survival is defined as material experiencing temperatures less than the impactor material’s estimated melting temperature (~2100 K, based on a commonly adopted Equation of State for serpentine). Importantly, oblique and low velocity impacts result in concentrations of unmelted projectile material down-range from the impact site. For the canonical 1 kmdiameter CC impactor considered here, with an impact angle ≤15◦ and velocity ≤10 km/s, this results in ~10^9–10^10 kg of C and ~10^8–10^9 kg of N being deposited a few tens of km down-range from the impact crater, where it might be accessible as a potential resource. Such low-velocity and oblique impacts have a low probability - we estimate that only ~5 such impacts may have occurred on the Moon in the last 3 billion years (the number of impacts of smaller impactors will have been higher, but they will concentrate lower masses of potential resources). As the estimated C and N concentrations from such impacts greatly exceed those expected for ices within individual permanently shadowed polar craters, searching for these rare impact sites may be worthwhile from a resource perspective. We briefly discuss how this might be achieved by means of orbital infrared remote-sensing measurements

    Thermodynamic behavior of IIA string theory on a pp-wave

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    We obtain the thermal one loop free energy and the Hagedorn temperature of IIA superstring theory on the pp-wave geometry which comes from the circle compactification of the maximally supersymmetric eleven dimensional one. We use both operator and path integral methods and find the complete agreement between them in the free energy expression. In particular, the free energy in the μ\mu \to \infty limit is shown to be identical with that of IIB string theory on maximally supersymmetric pp-wave, which indicates the universal thermal behavior of strings in the large class of pp-wave backgrounds. We show that the zero point energy and the modular properties of the free energy are naturally incorporated into the path integral formalism.Comment: 25 pages, Latex, JHEP style, v4: revised for clarity without change in main contents, version to appear in JHE

    PAM50 molecular intrinsic subtypes in the nurses' health Study cohorts

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    Background: Modified median and subgroup-specific gene subtypes by PAM50 and IHC surrogates improved to fair centering are two essential preprocessing methods to assign when Luminal subtypes were grouped together. Using the breast cancer molecular subtypes by PAM50. We evaluated the modified median method, our study consisted of 46% PAM50 subtypes derived from both methods in a subset of Luminal A, 18% Luminal B, 14% HER2-enriched, 15% Nurses' Health Study (NHS) and NHSII participants; correlat-Basal-like, and 8% Normal-like subtypes; 53% of tumor-ed tumor subtypes by PAM50 with IHC surrogates; and adjacent tissues were Normal-like. Women with the Basal-characterized the PAM50 subtype distribution, proliferation like subtype had a higher rate of relapse within 5 years. scores, and risk of relapse with proliferation and tumor size HER2-enriched subtypes had poorer outcomes prior to weighted (ROR-PT) scores in the NHS/NHSII. 1999. Methods: PAM50 subtypes, proliferation scores, and Conclusions: Either preprocessing method may be uti-ROR-PT scores were calculated for 882 invasive breast tumors lized to derive PAM50 subtypes for future studies. The and 695 histologically normal tumor-adjacent tissues. Cox majority of NHS/NHSII tumor and tumor-adjacent tissues proportional hazards models evaluated the relationship were classified as Luminal A and Normal-like, respectively. between PAM50 subtypes or ROR-PT scores/groups with Impact: Preprocessing methods are important for the recurrence-free survival (RFS) or distant RFS. accurate assignment of PAM50 subtypes. These data provide Results: PAM50 subtypes were highly comparable evidence that either preprocessing method can be used in between the two methods. The agreement between tumor epidemiologic studies

    Three decades of advancements in osteoarthritis research: insights from transcriptomic, proteomic, and metabolomic studies.

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    Osteoarthritis (OA) is a complex disease involving contributions from both local joint tissues and systemic sources. Patient characteristics, encompassing sociodemographic and clinical variables, are intricately linked with OA rendering its understanding challenging. Technological advancements have allowed for a comprehensive analysis of transcripts, proteomes and metabolomes in OA tissues/fluids through omic analyses. The objective of this review is to highlight the advancements achieved by omic studies in enhancing our understanding of OA pathogenesis over the last three decades. We conducted an extensive literature search focusing on transcriptomics, proteomics and metabolomics within the context of OA. Specifically, we explore how these technologies have identified individual transcripts, proteins, and metabolites, as well as distinctive endotype signatures from various body tissues or fluids of OA patients, including insights at the single-cell level, to advance our understanding of this highly complex disease. Omic studies reveal the description of numerous individual molecules and molecular patterns within OA-associated tissues and fluids. This includes the identification of specific cell (sub)types and associated pathways that contribute to disease mechanisms. However, there remains a necessity to further advance these technologies to delineate the spatial organization of cellular subtypes and molecular patterns within OA-afflicted tissues. Leveraging a multi-omics approach that integrates datasets from diverse molecular detection technologies, combined with patients' clinical and sociodemographic features, and molecular and regulatory networks, holds promise for identifying unique patient endophenotypes. This holistic approach can illuminate the heterogeneity among OA patients and, in turn, facilitate the development of tailored therapeutic interventions

    Synchronization and resonance in a driven system of coupled oscillators

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    We study the noise effects in a driven system of globally coupled oscillators, with particular attention to the interplay between driving and noise. The self-consistency equation for the order parameter, which measures the collective synchronization of the system, is derived; it is found that the total order parameter decreases monotonically with noise, indicating overall suppression of synchronization. Still, for large coupling strengths, there exists an optimal noise level at which the periodic (ac) component of the order parameter reaches its maximum. The response of the phase velocity is also examined and found to display resonance behavior.Comment: 17 pages, 3 figure

    Saturn's icy satellites and rings investigated by Cassini - VIMS. III. Radial compositional variability

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    In the last few years Cassini-VIMS, the Visible and Infared Mapping Spectrometer, returned to us a comprehensive view of the Saturn's icy satellites and rings. After having analyzed the satellites' spectral properties (Filacchione et al. (2007a)) and their distribution across the satellites' hemispheres (Filacchione et al. (2010)), we proceed in this paper to investigate the radial variability of icy satellites (principal and minor) and main rings average spectral properties. This analysis is done by using 2,264 disk-integrated observations of the satellites and a 12x700 pixels-wide rings radial mosaic acquired with a spatial resolution of about 125 km/pixel. The comparative analysis of these data allows us to retrieve the amount of both water ice and red contaminant materials distributed across Saturn's system and the typical surface regolith grain sizes. These measurements highlight very striking differences in the population here analyzed, which vary from the almost uncontaminated and water ice-rich surfaces of Enceladus and Calypso to the metal/organic-rich and red surfaces of Iapetus' leading hemisphere and Phoebe. Rings spectra appear more red than the icy satellites in the visible range but show more intense 1.5-2.0 micron band depths. The correlations among spectral slopes, band depths, visual albedo and phase permit us to cluster the saturnian population in different spectral classes which are detected not only among the principal satellites and rings but among co-orbital minor moons as well. Finally, we have applied Hapke's theory to retrieve the best spectral fits to Saturn's inner regular satellites using the same methodology applied previously for Rhea data discussed in Ciarniello et al. (2011).Comment: 44 pages, 27 figures, 7 tables. Submitted to Icaru

    Phase synchronization and noise-induced resonance in systems of coupled oscillators

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    We study synchronization and noise-induced resonance phenomena in systems of globally coupled oscillators, each possessing finite inertia. The behavior of the order parameter, which measures collective synchronization of the system, is investigated as the noise level and the coupling strength are varied, and hysteretic behavior is manifested. The power spectrum of the phase velocity is also examined and the quality factor as well as the response function is obtained to reveal noise-induced resonance behavior.Comment: to be published in Phys. Rev.

    Sex Segregation and Salary Structure in Academia

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    This article reports a study of aggregate unit salary levels, within a major research university. We analyze these salary levels, as they are influenced by unit sex composition, and modified by unit attainment levels—where unit refers to the departments, colleges and schools, and other academic divisions of the university. We investigate three central issues of sex and salary, previously overlooked in salary studies of academic employees: Do high proportions of women depress men's unit salary levels ("competition" hypothesis)? Are women's salary levels higher in male-dominated, and lower in female-dominated, units ("concentration" hypothesis)? Are men salary-compensated for working with women ("compensation" hypothesis)? The findings support none of these hypotheses. Rather, the relationship between unit sex composition and salary rests upon the connection between units' composition and attainment levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69126/2/10.1177_073088848100800103.pd

    Study of Tau-pair Production in Photon-Photon Collisions at LEP and Limits on the Anomalous Electromagnetic Moments of the Tau Lepton

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    Tau-pair production in the process e+e- -> e+e-tau+tau- was studied using data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000. The corresponding integrated luminosity is 650 pb^{-1}. The values of the cross-section obtained are found to be in agreement with QED predictions. Limits on the anomalous magnetic and electric dipole moments of the tau lepton are deduced.Comment: 20 pages, 9 figures, Accepted by Eur. Phys. J.
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