347 research outputs found

    Nucleon Resonances and Quark Structure

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    A pedagogical review of the past 50 years of study of resonances, leading to our understanding of the quark content of baryons and mesons. The level of this review is intended for undergraduates or first-year graduate students. Topics covered include: the quark structure of the proton as revealed through deep inelastic scattering; structure functions and what they reveal about proton structure; and prospects for further studies with new and upgraded facilities, particularly a proposed electron-ion collider.Comment: 21 pages, 15 figure

    Clinical Efficacy and Tolerability of Antihypertensive Therapy with Single Pill Combinations of Telmisartan in Patients with Arterial Hypertension in Clinical Practice According to the ON TIME Observational Study

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    Aim. To assess the clinical outcomes and tolerability of antihypertensive therapy with single pill combinations (SPC) amlodipine + telmisartan and hydrochlorothiazide + telmisartan in clinical practice.Material and methods. Patients with hypertension of grade 1-3 (n=13647; 57.6% women; age 59.3±11.4 years) who received therapy with SPC amlodipine + telmisartan or hydrochlorothiazide + telmisartan were included in an observational multicenter study. Information on complaints, history, previous therapy, history of novel coronavirus infection (COVID-19) during the previous year was obtained. Also, measurement of height, body weight, waist circumference (WC) and hips (HC), office blood pressure (BP) three times with an interval of 4 weeks, completion of questionnaires of satisfaction with therapy using the Likert scale, and assessement of adherence to therapy according to the patient's opinion was performed.Results. A statistically significant decrease in systolic (SBP) and diastolic blood pressure (DBP) was found both in all patients and in the analysis of subgroups according to the grade of hypertension (p<0.001 between visits in all cases). The degree of BP reduction depended on baseline BP levels. The average decrease in SBP/DBP at the 3rd visit for the grade 1 hypertension was 24.5/14.6 mm Hg, for the grade 2 hypertension – 34.4/16.8 mmHg, for the grade 3 hypertension – 49.6/22.1 mmHg (p<0.001 between groups). Target levels of SBP (≤140 mmHg) and DBP (≤90 mmHg) were achieved in 95.3% and 98.1% of patients, respectively. Target levels of SBP (≤130 mmHg) and DBP (≤80 mmHg) were achieved in 74.9% and 78.2% of patients, respectively. WC decreased by 0.5%; HC – by 1.5%; body weight – by 0.42% (p<0.001 in all cases). Scores in patients with a history of COVID-19 did not differ from those in individuals without a history of COVID-19. There were no violations of the therapy regimen during the observation period in 94% of patients. Most doctors and patients were "satisfied" or "completely satisfied" with the clinical effect, convenience and tolerability of therapy. Adverse events occurred in 1.35% of patients.Conclusion. Therapy with SPC amlodipine + telmisartan or hydrochlorothiazide + telmisartan in clinical practice had a high antihypertensive efficacy and had an optimal safety profile. The efficacy of therapy did not depend on the initial grade of hypertension, as well as the past infection with COVID19. The results of the ON TIME study confirm the feasibility of using the SPC amlodipine + telmisartan and hydrochlorothiazide + telmisartan for a wide range of hypertensive patients

    Improved approximation algorithm for k-level UFL with penalties, a simplistic view on randomizing the scaling parameter

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    The state of the art in approximation algorithms for facility location problems are complicated combinations of various techniques. In particular, the currently best 1.488-approximation algorithm for the uncapacitated facility location (UFL) problem by Shi Li is presented as a result of a non-trivial randomization of a certain scaling parameter in the LP-rounding algorithm by Chudak and Shmoys combined with a primal-dual algorithm of Jain et al. In this paper we first give a simple interpretation of this randomization process in terms of solving an aux- iliary (factor revealing) LP. Then, armed with this simple view point, Abstract. we exercise the randomization on a more complicated algorithm for the k-level version of the problem with penalties in which the planner has the option to pay a penalty instead of connecting chosen clients, which results in an improved approximation algorithm

    A new approach to calculate the gluon polarization

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    We derive the Leading-Order master equation to extract the polarized gluon distribution G(x;Q^2) = x \deltag(x;Q^2) from polarized proton structure function, g1p(x;Q^2). By using a Laplace-transform technique, we solve the master equation and derive the polarized gluon distribution inside the proton. The test of accuracy which are based on our calculations with two different methods confirms that we achieve to the correct solution for the polarized gluon distribution. We show that accurate experimental knowledge of g1p(x;Q^2) in a region of Bjorken x and Q^2, is all that is needed to determine the polarized gluon distribution in that region. Therefore, to determine the gluon polarization \deltag /g,we only need to have accurate experimental data on un-polarized and polarized structure functions (F2p (x;Q^2) and g1p(x;Q^2)).Comment: 12 pages, 5 figure

    Scanning Probe Techniques for Characterization of Vertically Aligned Carbon Nanotubes

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    This chapter presents the results of experimental studies of the electrical, mechanical and geometric parameters of vertically aligned carbon nanotubes (VA CNTs) using scanning probe microscopy (SPM). This chapter also presents the features and difficulties of characterization of VA CNTs in different scanning modes of the SPM. Advanced techniques for VA CNT characterization (the height, Young’s modulus, resistivity, adhesion and piezoelectric response) taking into account the features of the SPM modes are described. The proposed techniques allow to overcome the difficulties associated with the vertical orientation and high aspect ratio of nanotubes in determining the electrical and mechanical parameters of the VA CNTs by standard methods. The results can be used in the development of diagnostic methods as well as in nanoelectronics and nanosystem devices based on vertically aligned carbon nanotubes (memory elements, adhesive structures, nanoelectromechanical switches, emission structures, etc.)

    Patient adherence after coronary bypass grafting: different facets of same matter. A systematic review

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    Background. Adherence in cardiological patients is a leading challenge due to a high society burden imposed by cardiovascular diseases (CVDs) through morbidity, reduced life expectancy, disability and high mortality rates in population. Despite the availability of highly effective medicines and high-technology care, the success of CVD treatment remains insufficient. A particular focus should be placed on patients with previous coronary artery bypass grafting (CABG).Objectives. A review of reasoning for non-adherence to medication and non-medication management in post-CABG patients and current methods influencing it.Methods. Russian-language and foreign literature was mined in the eLibrary and PubMed databases with the query keywords “medication adherence” [приверженность терапии], “coronary artery disease” [ишемическая болезнь сердца], “coronary artery bypass surgery” [коронарное шунтирование], “coronary revascularisation” [вторичная профилактика после коронарного шунтирования]. The review included papers published within 2016–2020, as well as selected relevant publications from 2003–2015, to cover 52 sources irrespective of study design and language. Content and descriptive analyses were used as research tools.Results. Coronary heart disease (CHD) poses an important health, social and economic problem worldwide as a leading cause of reduced life expectancy, disability and high mortality. Non-compliance with medication significantly bursts medical expenditures [1]. Coronary artery bypass grafting is used widely to treat multivessel coronary lesions both in stable and acute CHD. Secondary preventive techniques successfully preclude adverse post-CABG events, but adherence to post-CABG treatment is often low. The non-adherence rationale rarely links to a single factor but is rather complex and multifaceted. It includes social and economic reasons, systemic health care or personnel, therapy and patient-related factors. Methods are developing and refining to improve adherence to both non-medication and medication interventions.Conclusion. Clinical trials to improve secondary prevention adherence in patients after coronary artery bypass grafting will allow a wider implementation of relevant methods in outpatient management of this patient category

    Exploring the polarization of gluons in the nucleon

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    We give an overview of the current status of investigations of the polarization of gluons in the nucleon. We describe some of the physics of the spin-dependent gluon parton distribution and its phenomenology in high-energy polarized hadronic scattering. We also review the recent experimental results.Comment: 10 pages, 13 figures. Talk presented at the "Second Meeting of the APS Topical Group on Hadronic Physics", Nashville, Tennessee, October 22-24, 2006. Reference adde

    Dijet production as a centrality trigger for p-p collisions at CERN LHC

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    We demonstrate that a trigger on hard dijet production at small rapidities allows to establish a quantitative distinction between central and peripheral collisions in pbar-p and p-p collisions at Tevatron and LHC energies. Such a trigger strongly reduces the effective impact parameters as compared to minimum bias events. This happens because the transverse spatial distribution of hard partons (x >~ 10^{-2}) in the proton is considerably narrower than that of soft partons, whose collisions dominate the total cross section. In the central collisions selected by the trigger, most of the partons with x >~ 10^{-2} interact with a gluon field whose strength rapidly increases with energy. At LHC (and to some extent already at Tevatron) energies the strength of this interaction approaches the unitarity ('black-body') limit. This leads to specific modifications of the final state, such as a higher probability of multijet events at small rapidities, a strong increase of the transverse momenta and depletion of the longitudinal momenta at large rapidities, and the appearance of long-range correlations in rapidity between the forward/backward fragmentation regions. The same pattern is expected for events with production of new heavy particles (Higgs, SUSY). Studies of these phenomena would be feasible with the CMS-TOTEM detector setup, and would have considerable impact on the exploration of the physics of strong gluon fields in QCD, as well as the search for new particles at LHC.Comment: 17 pages, Revtex 4, 14 EPS figures. Expanded discussion of some points, added 3 new figures and new references. Included comment on connection with cosmic ray physics near the GZK cutoff. To appear in Phys Rev

    MODELING THE PROCESSES OF MOISTURE SEPARATION IN THE PGV‑1000M STEAM GENERATOR OF A VVER‑1000 REACTOR

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    The paper considers the process of modeling moisture separation in the PGV‑1000M steam generator, and the possibility of using this model in the development and research of NPP steam generators.В работе рассмотрен процесс моделирования сепарации влаги в парогенераторе ПГВ‑1000 М и возможность применения настоящей модели при разработке парогенераторов АЭС и исследовании происходящих в них процессов
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