344 research outputs found

    Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in √sNN = 200 GeV Au+Au Collisions

    Get PDF
    A data-driven method was applied to measurements of Au+Au collisions at √sNN = 200 GeV made with the STAR detector at RHIC to isolate pseu- dorapidity distance ∆η-dependent and ∆η-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a component of the correlation that is ∆η-independent, which is likely dom- inated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity |η| 0.7

    Isolation of Flow and Nonflow Correlations by Two and Four Particle Cumulant Measurements of Azimuthal Harmonics in √Sɴɴ = GeV Au+Au Collisions

    Get PDF
    A data-driven method was applied to Au+Au collisions at √Sɴɴ = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δ η-dependent and Δ η-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a Δ η-independent component of the correlation, which is dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity | η | \u3c 1. In 20-30% central Au+Au collisions, the relative flow fluctuation was found to be 34% ± 2%(stat.) ± 3%(sys.) for particles with transverse momentum pT less than 2 GeV/c. The Δ η-dependent part, attributed to nonflow correlations, is found to be 5% ± 2%(sys.) relative to the flow of the measured second harmonic cumulant at | Δ η | \u3e 0.7

    Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in √\u3csup\u3es\u3c/sup\u3eNN=200 GeV Au+Au collisions

    Get PDF
    A data-driven method was applied to Au+Au collisions at √sNN = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δη-dependent and Δη-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a Δη-independent component of the correlation, which is dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity |η| \u3c 1. In 20–30% central Au+Au colli- sions, the relative flow fluctuation was found to be 34% ± 2%(stat.) ± 3%(sys.) for particles with transverse momentum PT less than 2 GeV/c. The Δη-dependent part, attributed to nonflow correlations, is found to be 5% ± 2%(sys.) relative to the flow of the measured second harmonic cumulant at |Δη| \u3e 0.7

    Сравнение показателей соотношений тромбоциты / лимфоциты и нейтрофилы / лимфоциты в качестве предикторов исхода COVID-19

    Get PDF
    Clinical presentation is an undependable prognostic indicator of COVID-19 (COronaVIrus Disease 2019). So, a more objective predictor is needed to precisely evaluate and classify the prognosis. Immune dysregulation to lymphocytes, mainly T-lymphocytes, have been noticed between COVID-19 patients. The aim. This study was planned to determine the role of platelet-to-lymphocyte count ratio and neutrophil-to-lymphocyte ratio in assessment of COVID-19 prognosis. Methods. 70 hospitalized patients with confirmed COVID-19 were included in this study. All included patients underwent a consistent clinical, radiological and blood examination. Laboratory analysis was made by means of a commercially accessible kit. Blood cells ratios were computed by dividing their absolute counts. Results. Non-significant association was found between laboratory data and COVID-19 clinical severity. A significant association between CT classification and platelet-to-lymphocyte count ratio (higher value in L type; p = 0.001) was detected. Platelet-to-lymphocyte count ratio was significantly higher among intubated cases. However, Non-significant association was found between neutrophil-to-lymphocyte ratio and need of endotracheal intubation. Conclusion. Routine blood values are abnormal in patients with COVID-19. Platelet-to-lymphocyte count ratio ratios could be used as more meaningful biomarker than other values in predicting the prognosis of COVID-19. LMR helpful in COVID-19 severity.Клиническая картина является ненадежным показателем прогноза исхода новой коронавирусной инфекции (НКИ), поэтому для точной оценки и классификации прогноза необходим более объективный прогнозирующий фактор. У пациентов, перенесших НКИ, отмечается нарушение регуляции иммунного ответа со стороны лимфоцитов, в основном Т-лимфоцитов. Целью исследования явилось определение роли показателей соотношений тромбоциты / лимфоциты и нейтрофилы / лимфоциты при оценке прогноза COVID-19. Материалы и методы. В исследование были включены госпитализированные пациенты (n = 70) с подтвержденным COVID-19 (COronaVIrus Disease 2019). У всех пациентов проводились последовательное клиническое и рентгенологическое обследование и анализ крови. Лабораторные анализы выполнялись с помощью коммерческого набора. Соотношения показателей клеток крови рассчитывались путем деления их абсолютного количества. Результаты. Обнаружена незначимая связь между лабораторными показателями и степенью тяжести COVID-19. Выявлена значимая связь между степенью поражения легких по данным компьютерной томографии и показателем соотношения тромбоциты / лимфоциты (более высокое значение для L-типа; p = 0,001). У интубированных пациентов соотношение показателя тромбоциты / лимфоциты было значимо выше. Однако обнаружена незначимая связь между показателем соотношения нейтрофилы / лимфоциты и необходимостью интубации трахеи. Заключение. У пациентов с COVID-19 наблюдаются отклонения показателей рутинных анализов крови. Показатель соотношения тромбоциты / лимфоциты может служить биомаркером при прогнозировании течения COVID-19, а показатель соотношения лимфоциты / моноциты полезен при прогнозировании степени тяжести COVID-19

    A new approach to cosmological perturbations in f(R) models

    Full text link
    We propose an analytic procedure that allows to determine quantitatively the deviation in the behavior of cosmological perturbations between a given f(R) modified gravity model and a LCDM reference model. Our method allows to study structure formation in these models from the largest scales, of the order of the Hubble horizon, down to scales deeply inside the Hubble radius, without employing the so-called "quasi-static" approximation. Although we restrict our analysis here to linear perturbations, our technique is completely general and can be extended to any perturbative order.Comment: 21 pages, 2 figures; Revised version according to reviewer's suggestions; Typos corrected; Added Reference

    A Unified Approach to Variational Derivatives of Modified Gravitational Actions

    Full text link
    Our main aim in this paper is to promote the coframe variational method as a unified approach to derive field equations for any given gravitational action containing the algebraic functions of the scalars constructed from the Riemann curvature tensor and its contractions. We are able to derive a master equation which expresses the variational derivatives of the generalized gravitational actions in terms of the variational derivatives of its constituent curvature scalars. Using the Lagrange multiplier method relative to an orthonormal coframe, we investigate the variational procedures for modified gravitational Lagrangian densities in spacetime dimensions n3n\geqslant 3. We study well-known gravitational actions such as those involving the Gauss-Bonnet and Ricci-squared, Kretchmann scalar, Weyl-squared terms and their algebraic generalizations similar to generic f(R)f(R) theories and the algebraic generalization of sixth order gravitational Lagrangians. We put forth a new model involving the gravitational Chern-Simons term and also give three dimensional New massive gravity equations in a new form in terms of the Cotton 2-form

    The metabolomic analysis of five Mentha species: cytotoxicity, anti-Helicobacter assessment, and the development of polymeric micelles for enhancing the anti-Helicobacter activity

    Get PDF
    Mentha species are medicinally used worldwide and remain attractive for research due to the diversity of their phytoconstituents and large therapeutic indices for various ailments. This study used the metabolomics examination of five Mentha species (M. suaveolens, M. sylvestris, M. piperita, M. longifolia, and M. viridis) to justify their cytotoxicity and their anti-Helicobacter effects. The activities of species were correlated with their phytochemical profiles by orthogonal partial least square discriminant analysis (OPLS-DA). Tentatively characterized phytoconstituents using liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS) included 49 compounds: 14 flavonoids, 10 caffeic acid esters, 7 phenolic acids, and other constituents. M. piperita showed the highest cytotoxicity to HepG2 (human hepatoma), MCF-7 (human breast adenocarcinoma), and CACO2 (human colon adenocarcinoma) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. OPLS-DA and dereplication studies predicted that the cytotoxic activity was related to benzyl glucopyranoside-sulfate, a lignin glycoside. Furthermore, M. viridis was effective in suppressing the growth of Helicobacter pylori at a concentration of 50 mg mL−1. OPLS-DA predicted that this activity was related to a dihydroxytrimethoxyflavone. M. viridis extract was formulated with Pluronic® F127 to develop polymeric micelles as a nanocarrier that enhanced the anti-Helicobacter activity of the extract and provided minimum inhibitory concentrations and minimum bactericidal concentrations of 6.5 and 50 mg mL−1, respectively. This activity was also correlated to tentatively identified constituents, including rosmarinic acid, catechins, carvone, and piperitone oxide

    Compactifying the state space for alternative theories of gravity

    Full text link
    In this paper we address important issues surrounding the choice of variables when performing a dynamical systems analysis of alternative theories of gravity. We discuss the advantages and disadvantages of compactifying the state space, and illustrate this using two examples. We first show how to define a compact state space for the class of LRS Bianchi type I models in RnR^n-gravity and compare to a non--compact expansion--normalised approach. In the second example we consider the flat Friedmann matter subspace of the previous example, and compare the compact analysis to studies where non-compact non--expansion--normalised variables were used. In both examples we comment on the existence of bouncing or recollapsing orbits as well as the existence of static models.Comment: 18 pages, revised to match published versio

    Dynamics of f(R)-cosmologies containing Einstein static models

    Full text link
    We study the dynamics of homogeneous isotropic FRW cosmologies with positive spatial curvature in f(R)f(R)-gravity, paying special attention to the existence of Einstein static models and only study forms of f(R)=Rnf(R)=R^n for which these static models have been shown to exist. We construct a compact state space and identify past and future attractors of the system and recover a previously discovered future attractor corresponding to an expanding accelerating model. We also discuss the existence of universes which have both a past and future bounce, a phenomenon which is absent in General Relativity.Comment: 14 pages, 6 figure

    Radiological Hazards and Natural Radionuclide Distribution in Granitic Rocks of Homrit Waggat Area, Central Eastern Desert, Egypt

    Full text link
    Natural radioactivity, radiological hazard, and petrological studies of Homrit Waggat granitic rocks, Central Eastern Desert, Egypt were performed in order to assess their suitability as ornamental stone. On the basis of mineralogical and geochemical compositions, Homrit Waggat granitic rocks can be subdivided into two subclasses. The first class comprises granodiorite and tonalite (I-type) and is ascribed to volcanic arc, whereas the second one includes alkali-feldspar granite, syenogranite, and albitized granite with high-K calc alkaline character, which is related to post-orogenic granites.238 U,226 Ra,232 Th, and40 K activities of natural radionuclides occurring in the examined rocks were measured radiometrically using sodium iodide detector. Furthermore, assessment of the hazard indices—such as: annual effective dose (AED) with mean values (0.11, 0.09, 0.07, 0.05, and 0.03, standard value = 0.07); gamma radiation index (Iγ) with mean values (0.6, 0.5, 0.4, 0.3, and 0.14, standard value = 0.5); internal (Hin) with mean values (0.6, 0.5, 0.4, 0.3, and 0.2, standard value = 1.0); external (Hex) index (0.5, 0.4, 0.3, 0.24, and 0.12, standard value = 1.0); absorbed gamma dose rate (D) with mean values (86.4, 75.9, 53.5, 43.6, and 20.8, standard value = 57); and radium equivalent activity (Raeq) with mean values (180, 154, 106.6, 90.1, and 42.7, standard value = 370)—were evaluated with the knowledge of the natural radionuclides. The result of these indices falls within the acceptable worldwide limits. Therefore, we suggest that these rocks are safe to be used in industrial applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.RF 3621/2021The researcher (Hamdy A. Awad) is funded by a scholarship under the Joint Executive Program between Egypt and Russian Federation. The work of the author A.E. and the APC were funded by the “Dunarea de Jos” University of Galati, Romania and grant no. RF 3621/2021
    corecore