921 research outputs found

    Measurement of jet pTp_{\mathrm{T}} spectra in Pb-Pb collisions at sNN=2.76 TeV\sqrt{s_{\mathrm{NN}}}=2.76~\mathrm{TeV} with the ALICE detector at the LHC

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    Reconstruction of jets in high-energy heavy-ion collisions is challenging due to the large and fluctuating background coming from the underlying event. We report results on full jet reconstruction, obtained from data collected in 2011 by the ALICE detector at LHC for Pb-Pb collisions at sNN=2.76 TeV\sqrt{s_{\mathrm{NN}}}=2.76~\mathrm{TeV}. The analysis makes use of the tracking system and the electromagnetic calorimeter. Signal jets, which come from hard scattered partons, are reconstructed using the anti-kTk_{\mathrm{T}} jet finder algorithm. The average background is subtracted on a jet-by-jet basis to reduce the contribution to the jet reconstructed energy coming from the underlying event. The jet spectrum is corrected to account for fluctuations in the background momentum density and detector effects through unfolding.Comment: 4 Pages, Hot Quarks 2012 Proceeding

    New results on jets and heavy flavor in heavy-ion collisions with ALICE

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    The large statistics accumulated during the LHC Run-1 and Run-2 have provided the unique opportunity to study the properties of the Quark-Gluon Plasma using rare hard probes. The ALICE Collaboration has presented new results on the jet shape observables in p--Pb and Pb--Pb collision. Using data from Run-2, the elliptic flow of open and hidden charm mesons have been measured with much better precision, confirming that charm quarks participate in the collective dynamic expansion with the medium. In p--Pb collisions the absence of jet quenching correlated with high event activity has been confirmed by a self-normalized semi-inclusive hadron+jet measurement.Comment: 8 pages, 5 figures, Proceedings of the Fifth Annual Conference of Large Hadron Collider Physics, May 15-20, 2017, Shanghai, Chin

    Measurement of jet pTp_{\rm T} spectra and RAAR_{\rm AA} in pp and Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector

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    Hard-scattered partons provide an ideal probe for the study of the Quark-Gluon Plasma because they are produced prior to the formation of the QCD medium in heavy-ion collisions. Jet production is therefore susceptible to modifications induced by the presence of the medium ("jet quenching"). Both RHIC and LHC experiments have provided compelling evidence of jet quenching. Jets are reconstructed in ALICE utilizing the central tracking system for the charged constituents and the Electromagnetic Calorimeter for the neutral constituents. Jet spectra are reported for central (0-10%) and semi-central (10-30%) Pb-Pb events at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV. The nuclear modification factor, determined using a pp baseline measured at the same collisional energy, shows a strong suppression of jet production in central Pb-Pb collisions with the expected centrality ordering. Observations are in qualitative agreement with medium-induced energy loss models. Furthermore, indication of a path-length dependence of jet suppression is inferred from measurements of the yields relative to the orientation of the event plane.Comment: 5 pages, 3 figures, Proceedings of the XXIV International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions Quark Matter 201

    UPAYA MENINGKATKAN MOTIVASI BELAJAR SISWA MELALUI MEDIA GAME EDUCATION DALAM PEMBELAJARAN IPS DI MTs HASBUR RACHMAN ALIF DESA LENGKONG WETAN KABUPATEN MAJALENGKA

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    ASEP SAMSUL MA'ARIF : Berdasarkan Observasiawal di kelas VII MTs Hasbur Rachman Alif terlihat proses pembelajaran IPS masih menggunakan media spidol dan papan tulis. Sehingga banyak siswa yang kurang memperhatikan guru pada saat proses pembelajaran., Hal ini berakibat pada kejenuhan dan kebosanan yang berdampak pada hasil belajar siswa yang kurang dari KKM yang diterapkan di MTs Hasbur Rachman Alif yakni 70. Tujuan penelitian ini untuk mengetahui bagaimana penerapan pembelajaran dengan menggunakan media Game Education pada mata pelajaran IPS Terpadu, aktivitas siswa dan kinerja guru dengan pembelajaran dengan menggunakan media Game Education, dan mengetahui motivasi belajar siswa sebelum dan setelah diterapkannya pembelajaran dengan menggunakan media Game education pada mata pelajaran IPS Terpadu di MTs Hasbur Rachman Alif. Pembelajaran dengan menggunakan media Game Education menekankan motivasi siswa untuk berpikir kritis dan menuangkan. Hal ini memudahkan siswa untuk mengakses materi IPS yang banyak dimanapun, serta mempemudah daya ingat siswa tentang apayatgtelah didapatkan selama proses pembelajaran. Penelitian ini menggunakan Penelitian Tindakan Kelas (pTK) yang dilaksanakan selama tiga siklus. Teknik Pengumpulan data menggunakan observasi, tes, dan dokumentasi. Subjek penelitian ini adalah siswa kelas VII MTs Hasbur Rachman Alif sebanyak 31 siswa yang terdiri dari 18 siswa laki-laki dan 13 siswa perempuan. Pembelajaran dengan menggunakan media Game Education dapat meningkatkan motivasi belajar siswa hal ini terlihat dari hasil tes yang telah dilakukan selama tiga siklus, dimana pada pratindakan (pretes) nilai sebesar 65,25 dan ketuntasan belajar 25 yo, siklus I nilai rata-rata sebesar 76,75 dan ketuntasan_ belajar siswa sebesar 65,5%o siklus II nilai rata-rata siswa 85,75 dan nilai ketuntasan belajar sebesar 90% siklus III dengan nilai rata-rata 92,25 dan ketuntasan belajar mengalami peningkatanya itu 97,5yo. Dengan demikian dapat disimpulkan bahwa pembelajaran dengan menggunakan media Game Education merupakan salah satu upaya untuk meningkatkan hasil belajar siswa pada mata pelajaran IPS Terpadu di MTs Hasbur Rachman Alif. Kata Kunci: Game Education, MotivasiBelajar, PTK

    Measurement of quarkonium production at forward rapidity in pp collisions at √s=7 TeV

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    The inclusive production cross sections at forward rapidity of J/ψ , ψ(2S) , Υ (1S) and Υ (2S) are measured in pp collisions at s√=7 TeV with the ALICE detector at the LHC. The analysis is based on a data sample corresponding to an integrated luminosity of 1.35 pb‾¹ . Quarkonia are reconstructed in the dimuon-decay channel and the signal yields are evaluated by fitting the μ+μ− invariant mass distributions. The differential production cross sections are measured as a function of the transverse momentum pT and rapidity y , over the ranges 0<pT<20 GeV/c for J/ψ , 0<pT<12 GeV/c for all other resonances and for \(2.5 . The measured cross sections integrated over pT and y , and assuming unpolarized quarkonia, are: σJ/ψ=6.69±0.04±0.63 μ b, σψ(2S)=1.13±0.07±0.19 μ b, σΥ(1S)=54.2±5.0±6.7 nb and σΥ(2S)=18.4±3.7±2.9 nb, where the first uncertainty is statistical and the second one is systematic. The results are compared to measurements performed by other LHC experiments and to theoretical models

    Event-by-event mean pT fluctuations in pp and Pb–Pb collisions at the LHC

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    Event-by-event fluctuations of the mean transverse momentum of charged particles produced in pp collisions at TeX TeX 0.9, 2.76 and 7 TeV, and Pb–Pb collisions at TeX TeX 2.76 TeV are studied as a function of the charged-particle multiplicity using the ALICE detector at the LHC. Dynamical fluctuations indicative of correlated particle emission are observed in all systems. The results in pp collisions show little dependence on collision energy. The Monte Carlo event generators PYTHIA and PHOJET are in qualitative agreement with the data. Peripheral Pb–Pb data exhibit a similar multiplicity dependence as that observed in pp. In central Pb–Pb, the results deviate from this trend, featuring a significant reduction of the fluctuation strength. The results in Pb–Pb are in qualitative agreement with previous measurements in Au–Au at lower collision energies and with expectations from models that incorporate collective phenomena

    Suppression of ψ(2S) production in p-Pb collisions at √sNN=5.02 TeV .

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    The ALICE Collaboration has studied the inclusive production of the charmonium state ψ(2S) in proton-lead (p-Pb) collisions at the nucleon-nucleon centre of mass energy √sNN = 5.02TeV at the CERN LHC. The measurement was performed at forward (2.03 < ycms < 3.53) and backward (−4.46 < ycms < −2.96) centre of mass rapidities, studying the decays into muon pairs. In this paper, we present the inclusive production cross sections σ (2S), both integrated and as a function of the transverse momentum pT, for the two ycms domains. The results are compared to those obtained for the 1S vector state (J/ψ), by showing the ratios between the production cross sections, as well as the double ratios [σ (2S)/σJ/ ]pPb/[σ (2S)/σJ/ ]pp between p-Pb and proton-proton collisions. Finally, the nuclear modification factor for inclusive ψ(2S) is evaluated and compared to the measurement of the same quantity for J/ψ and to theoretical models including parton shadowing and coherent energy loss mechanisms. The results show a significantly larger suppression of the ψ(2S) compared to that measured for J/ψ and to models. These observations represent a clear indication for sizeable final state effects on ψ(2S) production

    Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at s\sqrt{s} = 7 TeV

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    Prompt D meson and non-prompt J/ψ\psi yields are studied as a function of the multiplicity of charged particles produced in inelastic proton-proton collisions at a centre-of-mass energy of s=7\sqrt{s}=7 TeV. The results are reported as a ratio between yields in a given multiplicity interval normalised to the multiplicity-integrated ones (relative yields). They are shown as a function of the multiplicity of charged particles normalised to the average value for inelastic collisions (relative charged-particle multiplicity). D\)^0\), D\)^+\) and D\)^{*+}\) mesons are measured in five pTp_{\rm T} intervals from 1 to 20 GeV/cc and for ∣y∣1.3|y|1.3 GeV/cc and ∣y∣0|y|0, The fraction of non-prompt J/ψ\psi in the inclusive J/ψ\psi yields shows no dependence on the charged-particle multiplicity at central rapidity. Charm and beauty hadron relative yields exhibit a similar increase with increasing charged-particle multiplicity. The measurements are compared to PYTHIA 8, EPOS 3 and percolation calculations.publishedVersio

    Dehydroepiandrosterone sulfate mediates activation of transcription factors CREB and ATF-1 via a Gα11-coupled receptor in the spermatogenic cell line GC-2

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    AbstractDehydroepiandrosterone sulfate (DHEAS) is a circulating steroid produced in the adrenal cortex, brain, and gonads. Whereas a series of investigations attest to neuroprotective effects of the steroid in the brain, surprisingly little is known about the physiological effects of DHEAS on cells of the reproductive system. Here we demonstrate that DHEAS acting on the spermatogenic cell line GC-2 induces a time- and concentration-dependent phosphorylation of c-Src and Erk1/2 and activates the transcription factors activating transforming factor-1 (ATF-1) and cyclic AMP-responsive element binding protein (CREB). These actions are consistent with the non-classical signaling pathway of testosterone and suggest that DHEAS is a pro-androgen that is converted into testosterone in order to exert its biological activity. The fact, however, that steroid sulfatase mRNA was not detected in the GC-2 cells and the clear demonstration of DHEAS-induced activation of Erk1/2, ATF-1 and CREB after silencing the androgen receptor by small interfering RNA (siRNA) clearly contradict this assumption and make it appear unlikely that DHEAS has to be converted in the cytosol into a different steroid in order to activate the kinases and transcription factors mentioned. Instead, it is likely that the DHEAS-induced signaling is mediated through the interaction of the steroid with a membrane-bound G-protein-coupled receptor, since silencing of Guanine nucleotide-binding protein subunit alpha-11 (Gnα11) leads to the abolition of the DHEAS-induced stimulation of Erk1/2, ATF-1, and CREB. The investigation presented here shows a hormone-like activity of DHEAS on a spermatogenic cell line. Since DHEAS is produced in male and female reproductive organs, these findings could help to define new roles for DHEAS in the physiology of reproduction
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