475 research outputs found

    Il barone rampante di Italo Calvino: una lettura “didattica”

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    Il barone rampante di Italo Calvino non è semplicemente una fiaba, ma un testo composito che si presta a varie interpretazioni e appare ricco di implicazioni di natura “formativa”. In questo intervento, pur facendo cenno a molte possibili chiavi di lettura dell’opera, se ne propone un approccio finalizzato alla discussione del problema della ribellione adolescenziale e giovanile, partendo dalla riflessione sul significato pedagogico che l’atto di ribellione di Cosimo può assumere. L’opera di Calvino infatti appare adatta ad affrontare, nel vivo del contesto scolastico ma in forma mediata, una delle questioni che si presentano costantemente quasi in ogni classe e in ogni livello di scuola, quella del rifiuto, da parte di uno o più allievi, dello studio, dell’istituzione scolastica, delle istituzioni in genere.Not a mere fable, Calvino’s The Baron in the Trees is a multifaceted text which may have various interpretations and many implications for its “formative” nature. While touching on the many possible readings of Calvino’s novel, this essay aims, above all, to highlight and discuss the issue of youth rebellion, as exemplified by an analysis of Cosimo’s act of rebellion and its pedagogical meaning. Thus, Calvino’s novel can be seen as an ideal medium for tackling one of the more common issues found in schools at almost every stage within the school system, that is, students’ refusal of schooling, educational systems and institutions

    TAKE-OFF FORCES AND IMPULSES IN THE LONG JUMP

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    A series of jumps by an experienced female athlete were recorded with a force platform and a high-speed video camera. We obtained a wide range of run-up velocities by using direct intervention to set the length of the athlete’s run-up. In all jumps the horizontal take-off force was predominantly a backwards braking force and so the athlete’s horizontal velocity was substantially reduced during the take-off. The athlete’s breaking impulse increased with increasing run-up velocity, but not so much as to negate the increase in run-up velocity. The optimum long jump take-off technique is a compromise between the conflicting desires of generating vertical impulse and minimising the horizontal braking impulse. We currently have no firm recommendation as to the usefulness of a force platform in improving an athlete’s take-off technique

    Half-metallicity and Slater-Pauling behavior in the ferromagnetic Heusler alloys

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    Introductory chapter for the book "Halfmetallic Alloys - Fundamentals and Applications" to be published in the series Springer Lecture Notes on Physics, P. H. Dederichs and I. Galanakis (eds). It contains a review of the theoretical work on the half-metallic Heusler alloys.Comment: Introductory chapter for the book "Halfmetallic Alloys - Fundamentals and Applications" to be published in the series Springer Lecture Notes on Physics, P. H. Dederichs and I. Galanakis (eds

    Search for Λc+pK+π\Lambda_c^+ \to p K^+ \pi^- and Ds+K+K+πD_s^+ \to K^+ K^+ \pi^- Using Genetic Programming Event Selection

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    We apply a genetic programming technique to search for the double Cabibbo suppressed decays Λc+pK+π\Lambda_c^+ \to p K^+ \pi^- and Ds+K+K+πD_s^+ \to K^+ K^+ \pi^-. We normalize these decays to their Cabibbo favored partners and find BR(\text{BR}(\Lambda_c^+ \to p K^+ \pi^-)/BR()/\text{BR}(\Lambda_c^+ \to p K^- \pi^+)=(0.05±0.26±0.02)) = (0.05 \pm 0.26 \pm 0.02)% and BR(\text{BR}(D_s^+ \to K^+ K^+ \pi^-)/BR()/\text{BR}(D_s^+ \to K^+ K^- \pi^+)=(0.52±0.17±0.11)) = (0.52\pm 0.17\pm 0.11)% where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find <0.46< 0.46 % and <0.78 < 0.78% respectively. This is the first successful use of genetic programming in a high energy physics data analysis.Comment: 10 page

    Measurement of the D+ and Ds+ decays into K+K-K+

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    We present the first clear observation of the doubly Cabibbo suppressed decay D+ --> K-K+K+ and the first observation of the singly Cabibbo suppressed decay Ds+ --> K-K+K+. These signals have been obtained by analyzing the high statistics sample of photoproduced charm particles of the FOCUS(E831) experiment at Fermilab. We measure the following relative branching ratios: Gamma(D+ --> K-K+K+)/Gamma(D+ --> K-pi+pi+) = (9.49 +/- 2.17(statistical) +/- 0.22(systematic))x10^-4 and Gamma(Ds+ --> K-K+K+)/Gamma(Ds+ --> K-K+pi+) = (8.95 +/- 2.12(statistical) +2.24(syst.) -2.31(syst.))x10^-3.Comment: 10 pages, 8 figure

    A Non-parametric Approach to the D+ to K*0bar mu+ nu Form Factors

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    Using a large sample of D+ -> K- pi+ mu+ nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first measurements of the helicity basis form factors free from the assumption of spectroscopic pole dominance. We also present the first information on the form factor that controls the s-wave interference discussed in a previous paper by the FOCUS collaboration. We find reasonable agreement with the usual assumption of spectroscopic pole dominance and measured form factor ratios.Comment: 14 pages, 5 figures, and 2 tables. We updated the previous version by changing some words, removing one plot, and adding two tables. These changes are mostly stylisti

    Measurements of Ξc+\Xi_c^{+} Branching Ratios

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    Using data collected by the fixed target Fermilab experiment FOCUS, we measure the branching ratios of the Cabibbo favored decays Ξc+Σ+Kπ+\Xi_c^+ \to \Sigma^+K^-\pi^+, Ξc+Σ+Kˉ(892)0\Xi_c^+ \to \Sigma^+ \bar{K}^{*}(892)^0, and Ξc+Λ0Kπ+π+\Xi_c^+ \to \Lambda^0K^-\pi^+\pi^+ relative to Ξc+Ξπ+π+\Xi_c^+ \to \Xi^-\pi^+\pi^+ to be 0.91±0.11±0.040.91\pm0.11\pm0.04, 0.78±0.16±0.060.78\pm0.16\pm0.06, and 0.28±0.06±0.060.28\pm0.06\pm0.06, respectively. We report the first observation of the Cabibbo suppressed decay Ξc+Σ+K+K\Xi_c^+ \to \Sigma^+K^+K^- and we measure the branching ratio relative to Ξc+Σ+Kπ+\Xi_c^+ \to \Sigma^+K^-\pi^+ to be 0.16±0.06±0.010.16\pm0.06\pm0.01. We also set 90% confidence level upper limits for Ξc+Σ+ϕ\Xi_c^+ \to \Sigma^+ \phi and Ξc+Ξ(1690)0(Σ+K)K+\Xi_c^+ \to \Xi^*(1690)^0(\Sigma^+ K^-) K^+ relative to Ξc+Σ+Kπ+\Xi_c^+ \to \Sigma^+K^-\pi^+ to be 0.12 and 0.05, respectively. We find an indication of the decays Ξc+ΩK+π+\Xi_c^+ \to \Omega^-K^{+}\pi^+ and Ξc+Σ(1385)+Kˉ0\Xi_c^+ \to \Sigma^{*}(1385)^+ \bar{K}^0 and set 90% confidence level upper limits for the branching ratios with respect to Ξc+Ξπ+π+\Xi_c^+ \to \Xi^-\pi^+\pi^+ to be 0.12 and 1.72, respectively. Finally, we determine the 90% C.L. upper limit for the resonant contribution Ξc+Ξ(1530)0π+\Xi_c^+ \to \Xi^{*}(1530)^0 \pi^+ relative to Ξc+Ξπ+π+\Xi_c^+ \to \Xi^-\pi^+\pi^+ to be 0.10.Comment: 14 pages, 8 figure

    Dalitz plot analysis of D_s+ and D+ decay to pi+pi-pi+ using the K-matrix formalism

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    FOCUS results from Dalitz plot analysis of D_s+ and D+ to pi+pi-pi+ are presented. The K-matrix formalism is applied to charm decays for the first time to fully exploit the already existing knowledge coming from the light-meson spectroscopy experiments. In particular all the measured dynamics of the S-wave pipi scattering, characterized by broad/overlapping resonances and large non-resonant background, can be properly included. This paper studies the extent to which the K-matrix approach is able to reproduce the observed Dalitz plot and thus help us to understand the underlying dynamics. The results are discussed, along with their possible implications on the controversial nature of the sigma meson.Comment: To be submitted to Phys.Lett.B A misprint corrected in formula

    Measurement of the branching ratio of the decay D^0 -> \pi^-\mu^+\nu relative to D^0 -> K^-\mu^+\nu

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    We present a new measurement of the branching ratio of the Cabibbo suppressed decay D^0\to \pi^-\mu^+\nu relative to the Cabibbo favored decay D^0\to K^-\mu^+\nu and an improved measurement of the ratio |\frac{f_+^{\pi}(0)}{f_+^{K}(0)}|. Our results are 0.074 \pm 0.008 \pm 0.007 for the branching ratio and 0.85 \pm 0.04 \pm 0.04 \pm 0.01 for the form factor ratio, respectively.Comment: 13pages, 3 figure

    New Measurements of the D+ to K* mu nu Form Factor Ratios

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    Using a large sample of D+ to K- pi+ mu+ nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of two semileptonic form factor ratios: rv and r2. We find rv = 1.504 \pm 0.057 \pm 0.039 and r2 = 0.875 \pm 0.049 \pm 0.064. Our form factor results include the effects of the s-wave interference discussed in a previous paper.Comment: 12 pages, 5 figure
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