33,993 research outputs found

    Magnetic Properties of Pd_(0.996)Mn_(0.004) Films for High Resolution Thermometry

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    We have previously reported on the temperature and magnetic field dependence of the magnetic susceptibility of thin Pd_(1−x)Mn_x alloy films. Extensive new measurements on sputtered films show that a commercial quality sputtering process produces a film with the same dependence of Curie temperature on x as previously reported for bulk samples of the same material. These measurements and parameters from the Renormalization Group theory for a Heisenberg ferromagnet, yield an estimate for T_c of 1.16 ± 0.01 K when x − 0.004, consistent with previously reported bulk result

    Status Buying Responses in a Survey of Students and Variations in Informational Levels.

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    This article reports on a survey of a large number of undergraduate students in the U.S. They were queried about whether they preferred living in a society where they had high relative income (status) but low purchasing power or a society where they have low status, but high purchasing power.While the overwhelming majority indicate a desire to buy status, the information given about intergenerational mobilty and amenities like health available in the different socities makes a big difference in the responses. The data indicate that that the majority desiring to buy status disappears with better information.

    How mobile are dye adsorbates and acetonitrile molecules on the surface of TiO2 nanoparticles? A quasi-elastic neutron scattering study

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    Motions of molecules adsorbed to surfaces may control the rate of charge transport within monolayers in systems such as dye sensitized solar cells. We used quasi-elastic neutron scattering (QENS) to evaluate the possible dynamics of two small dye moieties, isonicotinic acid (INA) and bis-isonicotinic acid (BINA), attached to TiO2 nanoparticles via carboxylate groups. The scattering data indicate that moieties are immobile and do not rotate around the anchoring groups on timescales between around 10 ps and a few ns (corresponding to the instrumental range). This gives an upper limit for the rate at which conformational fluctuations can assist charge transport between anchored molecules. Our observations suggest that if the conformation of larger dye molecules varies with time, it does so on longer timescales and/or in parts of the molecule which are not directly connected to the anchoring group. The QENS measurements also indicate that several layers of acetonitrile solvent molecules are immobilized at the interface with the TiO2 on the measurement time scale, in reasonable agreement with recent classical molecular dynamics results

    Global constants in (2+1)--dimensional gravity

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    The extended conformal algebra (so)(2,3) of global, quantum, constants of motion in 2+1 dimensional gravity with topology R x T^2 and negative cosmological constant is reviewed. It is shown that the 10 global constants form a complete set by expressing them in terms of two commuting spinors and the Dirac gamma matrices. The spinor components are the globally constant holonomy parameters, and their respective spinor norms are their quantum commutators.Comment: 14 pages, to appear in Classical and Quantum Gravity, Spacetime Safari: Essays in Honor of Vincent Moncrief on the Classical Physics of Strong Gravitational Field

    Climate change and gender: what role for agricultural research among smallholder farmers in Africa?

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    This study was commissioned to provide an understanding of the complex impacts climate change will likely have on existing gender and social inequalities. It presents a conceptual framework for understanding the gender dimensions of climate change and smallholder agriculture in Sub-Saharan Africa; it outlines why climate change mitigation and adaptation activities should seek positive, equitable and empowering outcomes for disadvantaged and less powerful groups; and it identifies some of the questions and priorities that can be addressed in agricultural research in order to mitigate these inequities. Commissioned with support from CIAT, the Pan-Africa Bean Research Alliance (PABRA), the Eastern and Central Africa Bean Research Network (ECABREN), the Southern Africa Bean Research Network (SABRN), and the University of Greenwich
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