354 research outputs found

    Penggunaan Model Pembelajaran Kooperatif Tipe Two Stay Two Stray (Tsts) Untuk Meningkatkan Hasil Belajar Siswa Pada Materi Statistika

    Full text link
    Student learning achievement in statistical material is still relatively low, because the learning method used is still monotonous (conventional).  This study aims to improve the learning achievement of class XII Students of SMA Negeri 2 Salahutu on statistical material through the cooperative learning type two stay two stray. This type of research is a class action research consisting of two cycles, with each cycle consisting of two meeting. The subjects in this study were students of class XII-MIA2 with a sample of 20 students. Data collection techniques in this study were obtained from the results of observations and final test results of students in each cycle. Classical student learning outcomes from cycle I to cycle II increased by 15%. Based on results obtained, it can be concluded that using the cooperative learning of the two stay two stray type can improve the learning outcomes of class XII students of SMA Negeri 2 Salahutu on statistical matrial

    Measurements of Heavy Flavor and Di-electron Production at STAR

    Full text link
    Heavy quarks are produced early in the relativistic heavy ion collisions, and provide an excellent probe into the hot and dense nuclear matter created at RHIC. In these proceedings, we will discuss recent STAR measurements of heavy flavor production, to investigate the heavy quark interaction with the medium. Electromagnetic probes, such as electrons, provide information on the various stages of the medium evolution without modification by final stage interactions. Di-electron production measurements by STAR will also be discussed.Comment: 5 pages, 6 figures, proceedings for CPOD201

    Toward a Sustainable Marketplace: Expanding Options and Benefits for Consumers

    Get PDF
    While popular interest in sustainable consumption continues to grow, there is a persistent gap between consumers’ typically positive explicit attitudes towards sustainability and their actual consumption behaviours. This gap can be explained, in part, by the belief that choosing to consume sustainably is both constraining and reduces individual-level benefits. While the belief that sustainable consumption depends on making trade-offs is true in some contexts, increasingly consumers are finding that more sustainable forms of consumption can provide both an expanded set of options and additional, individual-level benefits. In this essay, we discuss and illustrate an expanded set of options and benefits across the consumption cycle: from acquisition to usage and disposition. An underlying theme is the separation of material ownership from the extraction of consumer benefits across the consumption cycle. We believe that this ongoing evolution of products - and even business models - has the potential to simultaneously increase value to consumers as well as speed progress towards a more sustainable marketplace

    Escherichia coli Nissle 1917 Antagonizes Candida albicans Growth and Protects Intestinal Cells from C. albicans -Mediated Damage

    Get PDF
    Candida albicans is a pathobiont of the gastrointestinal tract. It can contribute to the diversity of the gut microbiome without causing harmful effects. When the immune system is compromised, C. albicans can damage intestinal cells and cause invasive disease. We hypothesize that a therapeutic approach against C. albicans infections can rely on the antimicrobial properties of probiotic bacteria. We investigated the impact of the probiotic strain Escherichia coli Nissle 1917 (EcN) on C. albicans growth and its ability to cause damage to intestinal cells. In co-culture kinetic assays, C. albicans abundance gradually decreased over time compared with C. albicans abundance in the absence of EcN. Quantification of C. albicans survival suggests that EcN exerts a fungicidal activity. Cell-free supernatants (CFS) collected from C. albicans -EcN co-culture mildly altered C. albicans growth, suggesting the involvement of an EcN-released compound. Using a model of co-culture in the presence of human intestinal epithelial cells, we further show that EcN prevents C. albicans from damaging enterocytes both distantly and through direct contact. Consistently, both C. albicans ’s filamentous growth and microcolony formation were altered by EcN. Taken together, our study proposes that probiotic-strain EcN can be exploited for future therapeutic approaches against C. albicans infections

    System size and energy dependence of near-side di-hadron correlations

    Get PDF
    Two-particle azimuthal (Δϕ\Delta\phi) and pseudorapidity (Δη\Delta\eta) correlations using a trigger particle with large transverse momentum (pTp_T) in dd+Au, Cu+Cu and Au+Au collisions at sNN\sqrt{s_{{NN}}} =\xspace 62.4 GeV and 200~GeV from the STAR experiment at RHIC are presented. The \ns correlation is separated into a jet-like component, narrow in both Δϕ\Delta\phi and Δη\Delta\eta, and the ridge, narrow in Δϕ\Delta\phi but broad in Δη\Delta\eta. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated pTp_T. The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at sNN\sqrt{s_{{NN}}} = 200 GeV, is also found in Cu+Cu collisions and in collisions at sNN\sqrt{s_{{NN}}} =\xspace 62.4 GeV, but is found to be substantially smaller at sNN\sqrt{s_{{NN}}} =\xspace 62.4 GeV than at sNN\sqrt{s_{{NN}}} = 200 GeV for the same average number of participants (Npart \langle N_{\mathrm{part}}\rangle). Measurements of the ridge are compared to models.Comment: 17 pages, 14 figures, submitted to Phys. Rev.

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

    Get PDF
    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.

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

    Full text link
    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

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

    Get PDF
    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

    Strangeness Enhancement in Cu+Cu and Au+Au Collisions at \sqrt{s_{NN}} = 200 GeV

    Get PDF
    We report new STAR measurements of mid-rapidity yields for the Λ\Lambda, Λˉ\bar{\Lambda}, KS0K^{0}_{S}, Ξ\Xi^{-}, Ξˉ+\bar{\Xi}^{+}, Ω\Omega^{-}, Ωˉ+\bar{\Omega}^{+} particles in Cu+Cu collisions at \sNN{200}, and mid-rapidity yields for the Λ\Lambda, Λˉ\bar{\Lambda}, KS0K^{0}_{S} particles in Au+Au at \sNN{200}. We show that at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parameterization based on the fraction of participants that undergo multiple collisions

    An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement

    Full text link
    The QCD phase diagram lies at the heart of what the RHIC Physics Program is all about. While RHIC has been operating very successfully at or close to its maximum energy for almost a decade, it has become clear that this collider can also be operated at lower energies down to 5 GeV without extensive upgrades. An exploration of the full region of beam energies available at the RHIC facility is imperative. The STAR detector, due to its large uniform acceptance and excellent particle identification capabilities, is uniquely positioned to carry out this program in depth and detail. The first exploratory beam energy scan (BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades, most importantly a full barrel Time of Flight detector, are now completed which add new capabilities important for the interesting physics at BES energies. In this document we discuss current proposed measurements, with estimations of the accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure
    corecore