130 research outputs found

    Nuclear Physics Neutrino PreTown Meeting: Summary and Recommendations

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    In preparation for the nuclear physics Long Range Plan exercise, a group of 104 neutrino physicists met in Seattle September 21-23 to discuss both the present state of the field and the new opportunities of the next decade. This report summarizes the conclusions of that meeting and presents its recommendations. Further information is available at the workshop's web site. This report will be further reviewed at the upcoming Oakland Town Meeting.Comment: Latex, 31 pages. This version has been updated to include final Comments from the working group

    10,000 Standard Solar Models: a Monte Carlo Simulation

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    We have evolved 10,000 solar models using 21 input parameters that are randomly drawn for each model from separate probability distributions for every parameter. We use the results of these models to determine the theoretical uncertainties in the predicted surface helium abundance, the profile of the sound speed versus radius, the profile of the density versus radius, the depth of the solar convective zone, the eight principal solar neutrino fluxes, and the fractions of nuclear reactions that occur in the CNO cycle or in the three branches of the p-p chains. We also determine the correlation coefficients of the neutrino fluxes for use in analysis of solar neutrino oscillations. Our calculations include the most accurate available input parameters, including radiative opacity, equation of state, and nuclear cross sections. We incorporate both the recently determined heavy element abundances recommended by Asplund, Grevesse & Sauval (2005) and the older (higher) heavy element abundances recommended by Grevesse & Sauval (1998). We present best-estimates of many characteristics of the standard solar model for both sets of recommended heavy element compositions.Comment: ** John N. Bahcall passed away on August 17, 2005. Manuscript has 60 pages including 10 figure

    Implications of New Gallex Results for the MSW Solution of the Solar Neutrino Problem

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    We compare the implications for 7Be and pp neutrinos of the two MSW fits to the new GALLEX solar neutrino measurements . Small mixing angle solutions tend to suppress the former as electron-neutrinos, but not the latter, and large angle solutions tend to reduce both by about a factor of 2. The consequences for BOREXINO and similar solar neutrino--electron scattering experiments are discussed.Comment: 7 pages (plus 3 figures available upon request) UTAPHY-HEP-

    The Impact of Integrated Student Experiences on Learning

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    In a cluster of courses called Food for Thought, seven faculty from different departments (including Biology, Economics, Sociology, Chemistry, Health and Wellness, and Foreign Language) teach students about food information, food consumerism, nutrition and health. The classes all have a shared learning outcome focused on developing the student as an informed consumer of food.  Each semester, faculty teach a food-related course from their respective disciplinary perspective while also incorporating cross-course interactions that allow for both integration of disciplinary knowledge and student-to-student learning opportunities. Previous research demonstrated that this approach leads to student perceptions of learning gains (Authors, 2011). Building on that work, this research directly assesses student learning in the Food for Thought cluster. The results demonstrate that exposure to multiple disciplines covering a shared topic enhances learning through greater student ability to integrate diverse forms of knowledge and to see an issue from multiple perspectives. These findings demonstrate the value of multidisciplinary learning opportunities for students

    The Central Temperature of the Sun can be Measured via the 7^7Be Solar Neutrino Line

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    A precise test of the theory of stellar evolution can be performed by measuring the difference in average energy between the neutrino line produced by 7Be{\rm ^7Be} electron capture in the solar interior and the corresponding neutrino line produced in a terrestrial laboratory. The high temperatures in the center of the sun broaden the line asymmetrically, FWHM = 1.6~keV, and cause an average energy shift of 1.3~keV. The width of the 7^7Be neutrino line should be taken into account in calculations of vacuum neutrino oscillations.Comment: RevTeX file, 9 pages. For hardcopy with figure, send to [email protected]. Institute for Advanced Study number AST 93/4

    Enhancement of Radiation Effect on Cancer Cells by Gold-pHLIP

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    Previous research has shown that gold nanoparticles can increase the effectiveness of radiation on cancer cells. Improved radiation effectiveness would allow lower radiation doses given to patients, reducing adverse effects; alternatively, it would provide more cancer killing at current radiation doses. Damage from radiation and gold nanoparticles depends in part on the Auger effect, which is very localized; thus, it is important to place the gold nanoparticles on or in the cancer cells. In this work, we use the pH-sensitive, tumor-targeting agent, pH Low-Insertion Peptide (pHLIP), to tether 1.4-nm gold nanoparticles to cancer cells. We find that the conjugation of pHLIP to gold nanoparticles increases gold uptake in cells compared with gold nanoparticles without pHLIP, with the nanoparticles distributed mostly on the cellular membranes. We further find that gold nanoparticles conjugated to pHLIP produce a statistically significant decrease in cell survival with radiation compared with cells without gold nanoparticles and cells with gold alone. In the context of our previous findings demonstrating efficient pHLIP-mediated delivery of gold nanoparticles to tumors, the obtained results serve as a foundation for further preclinical evaluation of dose enhancement
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