1,160 research outputs found

    Inclusive pion double charge exchange on O-16 above the delta resonance

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    The forward inclusive pion double charge exchange reaction, ^{16}O(pi^-,pi^+)X, at T_0 = 0.50 and 0.75 GeV has been studied in the kinematical region where an additional pion production is forbidden by energy-momentum conservation. The experiment was performed with the SKS spectrometer at KEK PS. The measured ratio of double charge exchange cross-section for these energies dsigma(0.50 GeV)/dOmega / dsigma(0.75 GeV)/dOmega = 1.7 +/- 0.2, disagrees with the value of 7.2 predicted within the conventional sequential single charge exchange mechanism. Possible reasons for the disagreement are discussed in connection with the Glauber inelastic rescatterings.Comment: 4 pages, 5 figure

    NEPA at 21: Over the Hill Already?

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    The first part of this Comment will briefly review the somewhat meteoric rise of NEPA including the increase in public awareness which led to federal action, its projected effect, and the manner in which the courts seemed to be heading in their treatment of NEPA. The Comment will then review the decline of NEPA due to subsequent Supreme Court decisions. Finally, the Comment will consider possible remedies for the present anemic condition of this first federal environmental statute

    Artificial Insemination of Dairy Cattle.

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    Charge Form Factor and Cluster Structure of 6^6Li Nucleus

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    The charge form factor of 6{}^6Li nucleus is considered on the basis of its cluster structure. The charge density of 6{}^6Li is presented as a superposition of two terms. One of them is a folded density and the second one is a sum of 4{}^4He and the deuteron densities. Using the available experimental data for 4{}^4He and deuteron charge form factors, a good agreement of the calculations within the suggested scheme is obtained with the experimental data for the charge form factor of 6{}^6Li, including those in the region of large transferred momenta.Comment: 12 pages 5 figure

    Anticipatory and reactive mechanisms of habituation to visual distractors.

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    Human attention can rapidly habituate to irrelevant and repetitive visual distractors. Although this phenomenon is well-documented in behavioral studies, the neural mechanisms involved remain largely unknown. In this study, we investigated the neural correlates of attentional habituation using scalp electroencephalography (EEG). Participants performed a visual discrimination task while intermittently presented with salient distractor stimuli. The cost in reaction times (RT) associated with the distractor exhibited the typical time course of habituation, decreasing as a function of repeated exposure to the distractor. We found that this habituation coincided with both reactive and proactive changes in EEG activity. Post-distractor reactive EEG components emerged gradually over the course of the experiment, likely reflecting the operation of an inhibitory network aimed at suppressing distractor interference in the main task. Pre-stimulus α rhythms gradually tuned their power peaks to the anticipated moment of the distractor, suggesting the involvement of predictive inhibitory models based on prior experience with the distractor. Collectively, our findings suggest that attentional habituation involves multi-stage interacting mechanisms that anticipate the occurrence of a distractor and facilitate the rapid reallocation of attentional resources away from the distractor

    Pion-nucleus elastic scattering on 12C, 40Ca, 90Zr, and 208Pb at 400 and 500 MeV

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    Pion-nucleus elastic scattering at energies above the Delta(1232) resonance is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The present data provide an opportunity to study the interaction of pions with nuclei at energies where second-order corrections to impulse approximation calculations should be small. The results are compared with other data sets at similar energies, and with four different first-order impulse approximation calculations. Significant disagreement exists between the calculations and the data from this experiment

    The effects of perceived and received support on objective performance outcome.

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    This is a postprint of an article published in European Journal of Sport Science, 2008, Vol. 8, Issue 6, pp. 359 – 368 © 2008 copyright Taylor & Francis. European Journal of Sport Science is available online at: http://www.tandfonline.com/loi/tejs20In this study, we examined the main and stress-buffering effects of perceived and received support upon objective performance outcome. The sample consisted of 123 male British high performance golfers, mean age 25.3 years (SD = 5.4). Participants completed measures of perceived support, stressors, stress, and received support before competitions. After the competitions, performance outcome (number of shots) was recorded. When both types of support were considered separately, there were significant main effects for perceived (ΔR2 = .08, b = -.81, p < .01) and received support (ΔR2 = .05, b = -.68, p < .01) on performance. There were also significant stress-buffering effects for perceived (ΔR2 = .03, b = -.48, p = .02) and received support (ΔR2 = .06, b = -.61, p < .01). When both types of support were considered simultaneously, the significant main effect (DR2 = .09, p < .01) was primarily attributable to perceived support (b = -.63, p = .02). The significant stress-buffering effect (DR2 = .06, p = .01) was primarily attributable to received support (b = -.56, p = .04). These results demonstrate the beneficial influence of social support on performance. The findings highlight the need to recognise the distinction between perceived and received support, both in terms of theory and the design of social support interventions with athletes

    Artificial Insemination of Dairy Cattle.

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