40,078 research outputs found

    About An Apology for Idlers

    Get PDF
    I am in complete argument with Robert Louis Stevenson in his essay An Apology for Idlers. However, I cannot help wishing he were here today, so that he could tell me how to accomplish the nearly insurmountable task of being a successful idler..

    Brain food for babies

    Get PDF
    How does a mother supply a key building block of the brain required for neurodevelopment to her fetus in pregnancy? The critical requirement of docosahexaenoic acid (DHA) for fetal brain development, and the poor efficiency of its synthesis in humans, is a tricky metabolic problem to be overcome in pregnant women. Supplying this unique fatty acid to the fetus requires exquisite specificity and timing, processes that can unravel in disease conditions such as pre-eclampsia

    Emergence of equilibrium thermodynamic properties in quantum pure states. II. Analysis of a spin model system

    Full text link
    A system composed of identical spins and described by a quantum mechanical pure state is analyzed within the statistical framework presented in Part I of this work. We explicitly derive the typical values of the entropy, of the energy, and of the equilibrium reduced density matrix of a subsystem for the two different statistics introduced in Part I. In order to analyze their consistency with thermodynamics, these quantities of interest are evaluated in the limit of large number of components of the isolated system. The main results can be summarized as follows: typical values of the entropy and of the equilibrium reduced density matrix as functions of the internal energy in the fixed expectation energy ensemble do not satisfy the requirement of thermodynamics. On the contrary, the thermodynamical description is recovered from the random pure state ensemble (RPSE), provided that one considers systems large enough. The thermodynamic limit of the considered properties for the spin system reveals a number of important features. First canonical statistics (and thus, canonical typicality as long as the fluctuations around the average value are small) emerges without the need of assuming the microcanonical space for the global pure state. Moreover, we rigorously prove (i) the equivalence of the "global temperature," derived from the entropy equation of state, with the "local temperature" determining the canonical state of the subsystems; and (ii) the equivalence between the RPSE typical entropy and the canonical entropy for the overall system.Comment: 30 pages, 10 figure

    HOUSEHOLD EXPENDITURE ON MEAT VERSUS NONMEAT SOURCES OF PROTEIN IN THE UNITED STATES

    Get PDF
    Food Consumption/Nutrition/Food Safety,
    • …
    corecore