294 research outputs found

    M. M. Bakhtin as a University Professor

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    This article presents M. M. Bakhtin as a University professor through his own views of on the nature of university teaching: lecturing, seminars and colloquia, engaging students in debates and reflexive analysis of literary texts, “scientific thinking”, and working with bibliography. As a Chair of Russian and Foreign Literature department of the Mordovian National Pedagogical Institute (later the Mordovia State University), for a quarter of a century, Bakhtin was promoting teaching approaches that would support students’ informed, independent, analytical and reflexive learning. According to the minutes from different department meetings at his university, over the years, Bakhtin struggled to define and improve his own guidance and teaching in the Literature studies and the overall work of his department. His three pedagogical goals for a literary lecture were: 1) Communication of certain information on a given topic - establishing the level of students’ familiarity with the topic; 2) Fostering students’ scientific thinking; and 3) Fostering students’ aesthetic perception and taste. Some of his former students emphasized his erudition, pedagogic skill, and ability to stimulate his students’ imagination and reflective thinking

    M. M. Bakhtin as a University Professor

    Get PDF
    This article presents M. M. Bakhtin as a University professor through his own views of on the nature of university teaching: lecturing, seminars and colloquia, engaging students in debates and reflexive analysis of literary texts, “scientific thinking”, and working with bibliography. As a Chair of Russian and Foreign Literature department of the Mordovian National Pedagogical Institute (later the Mordovia State University), for a quarter of a century, Bakhtin was promoting teaching approaches that would support students’ informed, independent, analytical and reflexive learning. According to the minutes from different department meetings at his university, over the years, Bakhtin struggled to define and improve his own guidance and teaching in the Literature studies and the overall work of his department. His three pedagogical goals for a literary lecture were: 1) Communication of certain information on a given topic - establishing the level of students’ familiarity with the topic; 2) Fostering students’ scientific thinking; and 3) Fostering students’ aesthetic perception and taste. Some of his former students emphasized his erudition, pedagogic skill, and ability to stimulate his students’ imagination and reflective thinking

    The origins and spread of domestic horses from the Western Eurasian steppes

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    This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: All collapsed and paired-end sequence data for samples sequenced in this study are available in compressed fastq format through the European Nucleotide Archive under accession number PRJEB44430, together with rescaled and trimmed bam sequence alignments against both the nuclear and mitochondrial horse reference genomes. Previously published ancient data used in this study are available under accession numbers PRJEB7537, PRJEB10098, PRJEB10854, PRJEB22390 and PRJEB31613, and detailed in Supplementary Table 1. The genomes of ten modern horses, publicly available, were also accessed as indicated in their corresponding original publications57,61,85-87.NOTE: see the published version available via the DOI in this record for the full list of authorsDomestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 BC. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 BC, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 BC driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium BC Sintashta culture

    Polarization of a stored beam by spin-filtering

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    The PAX Collaboration has successfully performed a spin-filtering experiment with protons at the COSY-ring. The measurement allowed the determination of the spin-dependent polarizing cross section, that compares well with the theoretical prediction from the nucleon-nucleon potential. The test confirms that spin-filtering can be adopted as a method to polarize a stored beam and that the present interpretation of the mechanism in terms of the proton-proton interaction is correct. The outcome of the experiment is of utmost importance in view of the possible application of the method to polarize a beam of stored antiprotons.QC 20121212</p

    Direct observation of the dead-cone effect in quantum chromodynamics

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    The direct measurement of the QCD dead cone in charm quark fragmentation is reported, using iterative declustering of jets tagged with a fully reconstructed charmed hadron

    Direct observation of the dead-cone effect in quantum chromodynamics

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    At particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD) [1]. The vacuum is not transparent to the partons and induces gluon radiation and quark pair production in a process that can be described as a parton shower [2]. Studying the pattern of the parton shower is one of the key experimental tools in understanding the properties of QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass m and energy E, within a cone of angular size m/E around the emitter [3]. A direct observation of the dead-cone effect in QCD has not been possible until now, due to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible bound hadronic states. Here we show the first direct observation of the QCD dead-cone by using new iterative declustering techniques [4, 5] to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD, which is derived more generally from its origin as a gauge quantum field theory. Furthermore, the measurement of a dead-cone angle constitutes the first direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.The direct measurement of the QCD dead cone in charm quark fragmentation is reported, using iterative declustering of jets tagged with a fully reconstructed charmed hadron.In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass mQm_{\rm{Q}} and energy EE, within a cone of angular size mQm_{\rm{Q}}/EE around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics

    Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at <math display="inline"><mrow><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>200</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>

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    The polarization of Λ and Λ¯ hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sNN=200  GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild pT dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and pT dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.The polarization of Λ\Lambda and Λˉ\bar{\Lambda} hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sNN\sqrt{s_{NN}} = 200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild pTp_T dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagree with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and pTp_T dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy

    Heavy flavour decay muon production at forward rapidity in proton–proton collisions at √s=7 TeV

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    The production of muons from heavy flavour decays is measured at forward rapidity in proton–proton collisions at √s=7 TeV collected with the ALICE experiment at the LHC. The analysis is carried out on a data sample corresponding to an integrated luminosity Lint=16.5 nb−1. The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5<y<4, over the transverse momentum range 2<pt<12 GeV/c. The results are compared to predictions based on perturbative QCD calculations

    Measurement of the radius dependence of charged-particle jet suppression in Pb–Pb collisions at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV

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    The ALICE Collaboration reports a new differential measurement of inclusive jet suppression using pp and Pb–Pb collision data at center-of-mass energy per nucleon–nucleon collision sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV. Charged-particle jets are reconstructed using the anti-kTk_{\rm T} algorithm with resolution parameters RR = 0.2, 0.3, 0.4, 0.5, and 0.6 in pp collisions and RR = 0.2, 0.4, 0.6 in central (0–10\%), semi-central (30–50\%), and peripheral (60–80\%) Pb–Pb collisions. The analysis uses a novel approach based on machine learning to mitigate the influence of jet background in central heavy-ion collisions, which enables measurements of inclusive jet suppression for jet pT≄40p_{\rm T} \ge 40 GeV/cc in central collisions at a resolution parameter of RR = 0.6. This is the lowest value of jet pTp_{\rm T} achieved for inclusive jet measurements at RR = 0.6 at the LHC, and is an important step for discriminating different models of jet quenching in the quark-gluon plasma. The transverse momentum spectra, nuclear modification factors, and derived cross section and nuclear modification factor ratios for different jet resolution parameters of charged-particle jets are presented and compared to model predictions. A mild dependence of the nuclear modification factor ratios on collision centrality and resolution parameter is observed. The results are compared to a variety of jet quenching models with varying levels of agreement, demonstrating the effectiveness of this observable to discriminate between models.The ALICE Collaboration reports a new differential measurement of inclusive jet suppression using pp and Pb−-Pb collision data at center-of-mass energy per nucleon-nucleon collision sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV. Charged-particle jets are reconstructed using the anti-kTk_{\rm T} algorithm with resolution parameters R=R = 0.2, 0.3, 0.4, 0.5, and 0.6 in pp collisions and R=R = 0.2, 0.4, 0.6 in central (0−-10%), semi-central (30−-50%), and peripheral (60−-80%) Pb−-Pb collisions. The analysis uses a novel approach based on machine learning to mitigate the influence of jet background in central heavy-ion collisions, which enables measurements of inclusive jet suppression for jet pT≄40p_{\rm T} \geq 40 GeV/cc in central collisions at a resolution parameter of R=0.6R = 0.6. This is the lowest value of jet pTp_{\rm T} achieved for inclusive jet measurements at R=0.6R=0.6 at the LHC, and is an important step for discriminating different models of jet quenching in the quark-gluon plasma. The transverse momentum spectra, nuclear modification factors, and derived cross section and nuclear modification factor ratios for different jet resolution parameters of charged-particle jets are presented and compared to model predictions. A mild dependence of the nuclear modification factor ratios on collision centrality and resolution parameter is observed. The results are compared to a variety of jet quenching models with varying levels of agreement, demonstrating the effectiveness of this observable to discriminate between models
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