1,086 research outputs found
Systematic Search of Exactly Solvable Non-Central Potentials
Recently developed supersymmetric perturbation theory has been successfully
employed to make a complete mathematical analysis the reason behind exact
solvability of some non-central potentials. This investigation clarifies once
more the effectiveness of the present formalism.Comment: 7 pages, no figure
Implications of a Quantum Mechanical Treatment of the Universe
We attempt to treat the very early Universe according to quantum mechanics.
Identifying the scale factor of the Universe with the width of the wave packet
associated with it, we show that there cannot be an initial singularity and
that the Universe expands. Invoking the correspondence principle, we obtain the
scale factor of the Universe and demonstrate that the causality problem of the
standard model is solved.Comment: LaTex, 5 pages, 1 figure, to be published in Mod. Phys. Lett.
COMPARISON OF PHYSICAL ACTIVITY LEVELS OF MIDDLE SCHOOL AND HIGH SCHOOL STUDENTS
The aim of this study is to compare the physical activity levels of middle school and high school students in Çanakkale province. The study included 426 female and 417 male students aged 10-17 years who voluntarily participated. The PAQ survey developed by Kowalski et al. was used to determine physical activity levels of students participating in the study. The responses of students to the survey questions had mean and standard deviation calculated and the T test used for analysis with SPSS. For middle school students, the mean age of female students was 12.16±1.23 and the mean age of male students was 12.23±1.24 years. For high school, the mean age of female students was 16.31±1.17 and the mean age of male students was 16.32±1.29 years. In terms of BMI, the value for female middle school students was 18.95±3.13 and for male middle school students was 19.18±3.78, while for female high school students it was 20.92±3.31 and for male high school students it was 22.21±5.36. The physical activity scores for female and male middle school students were 2.71±0.79 and 2.93±0.77, respectively. The physical activity scores for female and male high school students were 1.88±0.61 and 2.36±0.73, respectively. For middle school students the physical activity scores were found to be high for both genders compared to high school students. Physical activity scores for female students were lower compared to males in both school types. Article visualizations
Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH_(2)PO_4
We demonstrate cathodes for solid acid fuel cells fabricated by vapor deposition of platinum from the metalorganic precursor Pt(acac)_2 on the solid acid
CsH_(2)PO_4 at 210 °C. A network of platinum nanoparticles with diameters of 2−4 nm serves as both the oxygen reduction catalyst and the electronic conductor in the electrode. Electrodes with a platinum content of 1.75 mg/cm^2 are more active for oxygen reduction than previously reported electrodes with a platinum content of 7.5 mg/cm^2. Electrodes containing <1.75 mg/cm^2 of platinum show significantly reduced catalytic activity and increased ohmic resistance indicative of a highly discontinuous catalytic-electronic platinum network
An Upper Bound on the Higgs Boson Mass from a Positivity Condition on the Mass Matrix
We impose the condition that the eigenvalues of the mass matrix in the
shifted Lagrangian density be positive at \phi=\phi_{0}, the vacuum expectation
value of the scalar field. Using the one-loop effective potential of the
standard model, this condition leads to an upper bound on the Higgs boson mass
m_{H}: m_{H}<230GeV, for a top quark mass of 175GeV.Comment: LaTex, 5 page
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