563 research outputs found

    Target and Projectile: Material Effects on Crater Excavation and Growth

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    Scaling relationships allow the initial conditions of an impact to be related to the excavation flow and final crater size and have proven useful in understanding the various processes that lead to the formation of a planetary-scale crater. In addition, they can be examined and tested through laboratory experiments in which the initial conditions of the impact are known and ejecta kinematics and final crater morphometry are measured directly. Current scaling relationships are based on a point-source assumption and treat the target material as a continuous medium; however, in planetary-scale impacts, this may not always be the case. Fragments buried in a megaregolith, for instance, could easily approach or exceed the dimensions of the impactor; rubble-pile asteroids could present similar, if not greater, structural complexity. Experiments allow exploration into the effects of target material properties and projectile deformation style on crater excavation and dimensions. This contribution examines two of these properties: (1) the deformation style of the projectile, ductile (aluminum) or brittle (soda-lime glass) and (2) the grain size of the target material, 0.5-1 mm vs. 1-3 mm sand

    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

    Which comforting messages really work best? A different perspective on Lemieux and Tighe’s “receiver perspective”

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    Abstract OnlyThis article responds critically to a recent article by Lemieux and Tighe (Communication Research Reports, 21, 144–153, 2004) in which the authors conclude that recipients of comforting efforts prefer messages that exhibit a moderate rather than high level of person centeredness. It is argued that an erroneous assumption made by Lemieux and Tighe about the status of “receiver perspective” research on the comforting process led to faulty interpretations of the data and unwarranted conclusions about recipient preferences regarding comforting messages. Alternative interpretations of Lemieux and Tighe's data are presented; these are guided by the extensive previous research that has assessed evaluations and outcomes of comforting messages

    The CSU Accelerator and FEL Facility

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    The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discusse

    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

    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
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