269 research outputs found

    INFLUENCE OF NORMS AND METHODS OF PLANT GROWTH REGULATOR VERMYSTYM APPLICATION ON QUALITY INDICATORS AND PRODUCTIVITY OF POTATO

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    The article investigates the effect of different norms and methods of plant growth regulator Vermystym application on plant height, number of stems in a bush, stand density, yield and quality of two varieties of potato tubers. It is found that pre-planting cultivation of potato tubers with Vermystym in a dose of 8 l/t and double spraying of potato tops of mid-season potato variety Roko and middle-late potato variety Picasso in periods of bud-formation and blooming at a rate of 14l/ha increased the number of stems, average potato weight yield, and the content of dry matter and starch. According to the conducted research, an environmentally-friendly potato production gain method is developed

    Impact of breastfeeding on the incidence of respiratory and somatic pathology in infants and preschool children

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    The purpose of the study is to evaluate the history and morbidity data in children with different durations of breastfeeding.Цель исследования – оценка анамнеза, данных заболеваемости у детей с различной продолжительностью грудного вскармливания

    Fostering University Students’ Digital Skills: De Jure vs De Facto

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    В данной исследовательской статье рассматривается вопрос формирования цифровых навыков в процессе обучения у студентов, осваивающих в вузах различные направления подготовки. Обсуждается ситуация с наличием специфических, актуальных для конкретных направлений подготовки, и сквозных, общих, цифровых навыков, формируемых за пределами связанных с ИТ-индустрией направлений подготовки. Высказано предположение, что во всех направлениях подготовки заложена «подушка» общих цифровых навыков, которая может быть закреплена как де-юре – в методической и нормативной базе образовательного процесса, так и де-факто – в практиках обучения. Входе исследования определена рамка общих и специфических цифровых навыков. Для проверки гипотез анализируются две группыданных: нормативная иметодическая базыобразовательных программ (развитие де-юре) и результатыанкетирования студентов, позволяющего определить, как интегрированы практики развития и использования цифровых навыков в их учебе (развитие де-факто). Исследование проводилось по семи направлениям подготовки с заведомо широким диапазоном – от медицины до информационных технологий и филологии. Показано, что цифровые навыки де-юре отражены во всех направлениях подготовки, но нормативное закрепление преимущественно имеют общие, а не специфические цифровые навыки. Установлено наличие разрыва между де-юре и де-факто развитием цифровых навыков, данный разрыв варьируется на различных направлениях подготовки. Результаты исследования могут быть полезны в разработке стратегий развития цифровых навыков в вузах, а также при корректировке методической базы образовательных программ в части развития цифровых навыков.The article discusses the problem of within-the-education-process fostering digital skills among university students of various training programs. The specific skills (relevant to a particular sphere) are differentiated from the general ones (digital skills formed beyond the IT industry). The authors suggest that all training programs contain a «pillow» of general digital skills, which can be fixed both de jure – in the methodological and regulatory bases of the educational process, and de facto – in teaching practices. The study identifies a framework for general and specific digital skills. To test the hypotheses, two groups of data are analyzed: the normative and methodological bases of educational programs (fostering skills de jure) and students’ questionnaire answers on how the practices of developing and using digital skills in their studies are integrated (fostering skills de facto). The research is carried out in seven programs with obviously wide differences – from medicine to information technology and philology. The research has shown that digital skills are de jure represented in all programs, but normative consolidation is more typical for general skills, not for specific digital ones. There is identified a gap between de jure and de facto fostering digital skills, and this gap is various for different programs. The research results can be used in universities when designing strategies to form digital skills or when modifying such skills-related methodological bases of training programs.Авторы выражают особую благодарность Вере Андреевне Мальцевой, научному сотруднику Института образования НИУ ВШЭ, за подробные консультации и поддержку при проведении исследования и подготовке текста статьи. Также авторы выражают признательность проректору по учебной работе Московского политехнического университета Гюзель Харрясовне Шарипзяновой и начальнику управления маркетинга Московского Политеха Сергею Юрьевичу Рясову – за помощь в сборе эмпирических данных, а рецензентам – за ценные замечания в ходе подготовки данной статьи к публикации.The authors would like to express special gratitude to Vera A. Maltseva, Research Fellow at the Institute of Education, National Research University Higher School of Economics, for detailed advice and support during the research and preparation of the article text. We also express our gratitude to Guzel Kh. Sharipzyanova, Vice-Rector for Academic Affairs of Moscow Polytechnic University, and to Sergei Yu. Ryasov, Head of the Marketing Department of Moscow Polytechnic University, for their help in collecting empirical data. Special thanks to the reviewers of this article for valuable pre-publication comment

    Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV Au+Au Collisions

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    A data-driven method was applied to measurements of Au+Au collisions at sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δη\Delta\eta-dependent and Δη\Delta\eta-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a component of the correlation that is Δη\Delta\eta-independent, which is likely dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η\eta within the measured range of pseudorapidity η<1|\eta|<1. The relative flow fluctuation was found to be 34%±2%(stat.)±3%(sys.)34\% \pm 2\% (stat.) \pm 3\% (sys.) for particles of transverse momentum pTp_{T} less than 22 GeV/cc. The Δη\Delta\eta-dependent part may be attributed to nonflow correlations, and is found to be 5%±2%(sys.)5\% \pm 2\% (sys.) relative to the flow of the measured second harmonic cumulant at Δη>0.7|\Delta\eta| > 0.7

    Inclusive charged hadron elliptic flow in Au + Au collisions at sNN\sqrt{s_{NN}} = 7.7 - 39 GeV

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    A systematic study is presented for centrality, transverse momentum (pTp_T) and pseudorapidity (η\eta) dependence of the inclusive charged hadron elliptic flow (v2v_2) at midrapidity(η<1.0|\eta| < 1.0) in Au+Au collisions at sNN\sqrt{s_{NN}} = 7.7, 11.5, 19.6, 27 and 39 GeV. The results obtained with different methods, including correlations with the event plane reconstructed in a region separated by a large pseudorapidity gap and 4-particle cumulants (v24v_2{4}), are presented in order to investigate non-flow correlations and v2v_2 fluctuations. We observe that the difference between v22v_2{2} and v24v_2{4} is smaller at the lower collision energies. Values of v2v_2, scaled by the initial coordinate space eccentricity, v2/εv_{2}/\varepsilon, as a function of pTp_T are larger in more central collisions, suggesting stronger collective flow develops in more central collisions, similar to the results at higher collision energies. These results are compared to measurements at higher energies at the Relativistic Heavy Ion Collider (sNN\sqrt{s_{NN}} = 62.4 and 200 GeV) and at the Large Hadron Collider (Pb + Pb collisions at sNN\sqrt{s_{NN}} = 2.76 TeV). The v2(pT)v_2(p_T) values for fixed pTp_T rise with increasing collision energy within the pTp_T range studied (<2GeV/c< 2 {\rm GeV}/c). A comparison to viscous hydrodynamic simulations is made to potentially help understand the energy dependence of v2(pT)v_{2}(p_{T}). We also compare the v2v_2 results to UrQMD and AMPT transport model calculations, and physics implications on the dominance of partonic versus hadronic phases in the system created at Beam Energy Scan (BES) energies are discussed.Comment: 20 pages, 12 figures. Version accepted by PR

    Measurements of D0D^{0} and DD^{*} Production in pp + pp Collisions at s\sqrt{s} = 200 GeV

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    We report measurements of charmed-hadron (D0D^{0}, DD^{*}) production cross sections at mid-rapidity in pp + pp collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays D0Kπ+D^{0}\rightarrow K^{-}\pi^{+}, D+D0π+Kπ+π+D^{*+}\rightarrow D^{0}\pi^{+}\rightarrow K^{-}\pi^{+}\pi^{+} and their charge conjugates, covering the pTp_T range of 0.6-2.0 GeV/cc and 2.0-6.0 GeV/cc for D0D^{0} and D+D^{*+}, respectively. From this analysis, the charm-pair production cross section at mid-rapidity is dσ/dyy=0ccˉd\sigma/dy|_{y=0}^{c\bar{c}} = 170 ±\pm 45 (stat.) 59+38^{+38}_{-59} (sys.) μ\mub. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a Fixed-Order Next-to-Leading Logarithm calculation.Comment: 15 pages, 16 figures. Revised version submitted to Phys. Rev.

    Charged-to-neutral correlation at forward rapidity in Au+Au collisions at sNN\sqrt{s_{NN}}=200 GeV

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    Event-by-event fluctuations of the ratio of inclusive charged to photon multiplicities at forward rapidity in Au+Au collision at sNN\sqrt{s_{NN}}=200 GeV have been studied. Dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidences of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as baselines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A non-zero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation due to particle decay. Results are compared to the expectations based on the generic production mechanism of pions due to isospin symmetry, for which no significant (<1%) deviation is observed.Comment: 14 pages, 6 figure

    Studies of di-jet survival and surface emission bias in Au+Au collisions via angular correlations with respect to back-to-back leading hadrons

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    We report first results from an analysis based on a new multi-hadron correlation technique, exploring jet-medium interactions and di-jet surface emission bias at RHIC. Pairs of back-to-back high transverse momentum hadrons are used for triggers to study associated hadron distributions. In contrast with two- and three-particle correlations with a single trigger with similar kinematic selections, the associated hadron distribution of both trigger sides reveals no modification in either relative pseudo-rapidity or relative azimuthal angle from d+Au to central Au+Au collisions. We determine associated hadron yields and spectra as well as production rates for such correlated back-to-back triggers to gain additional insights on medium properties.Comment: By the STAR Collaboration. 6 pages, 2 figure

    Observation of the antimatter helium-4 nucleus

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    High-energy nuclear collisions create an energy density similar to that of the universe microseconds after the Big Bang, and in both cases, matter and antimatter are formed with comparable abundance. However, the relatively short-lived expansion in nuclear collisions allows antimatter to decouple quickly from matter, and avoid annihilation. Thus, a high energy accelerator of heavy nuclei is an efficient means of producing and studying antimatter. The antimatter helium-4 nucleus (4Heˉ^4\bar{He}), also known as the anti-{\alpha} (αˉ\bar{\alpha}), consists of two antiprotons and two antineutrons (baryon number B=-4). It has not been observed previously, although the {\alpha} particle was identified a century ago by Rutherford and is present in cosmic radiation at the 10% level. Antimatter nuclei with B < -1 have been observed only as rare products of interactions at particle accelerators, where the rate of antinucleus production in high-energy collisions decreases by about 1000 with each additional antinucleon. We present the observation of the antimatter helium-4 nucleus, the heaviest observed antinucleus. In total 18 4Heˉ^4\bar{He} counts were detected at the STAR experiment at RHIC in 109^9 recorded Au+Au collisions at center-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon pair. The yield is consistent with expectations from thermodynamic and coalescent nucleosynthesis models, which has implications beyond nuclear physics.Comment: 19 pages, 4 figures. Submitted to Nature. Under media embarg

    Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at sNN=200\sqrt{s_{NN}}=200 GeV

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    Dihadron azimuthal correlations containing a high transverse momentum (\pt) trigger particle are sensitive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium, i.e. jet-quenching. Previous measurements revealed a strong modification to dihadron azimuthal correlations in Au+Au collisions with respect to \pp\ and \dAu\ collisions. The modification increases with the collision centrality, suggesting a path-length dependence to the jet-quenching effect. This paper reports STAR measurements of dihadron azimuthal correlations in mid-central (20-60\%) Au+Au collisions at \snn=200~GeV as a function of the trigger particle's azimuthal angle relative to the event plane, \phis=|\phit-\psiEP|. The azimuthal correlation is studied as a function of both the trigger and associated particle \pt. The subtractions of the combinatorial background and anisotropic flow, assuming Zero Yield At Minimum (\zyam), are described. The away-side correlation is strongly modified, and the modification varies with \phis, which is expected to be related to the path-length that the away-side parton traverses. The pseudo-rapidity (\deta) dependence of the near-side correlation, sensitive to long range \deta correlations (the ridge), is also investigated. The ridge and jet-like components of the near-side correlation are studied as a function of \phis. The ridge appears to drop with increasing \phis while the jet-like component remains approximately constant. ...Comment: 50 pages, 39 figures, 6 table
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