488 research outputs found

    Affine su(3) and su(4) fusion multiplicities as polytope volumes

    Get PDF
    Affine su(3) and su(4) fusion multiplicities are characterised as discretised volumes of certain convex polytopes. The volumes are measured explicitly, resulting in multiple sum formulas. These are the first polytope-volume formulas for higher-rank fusion multiplicities. The associated threshold levels are also discussed. For any simple Lie algebra we derive an upper bound on the threshold levels using a refined version of the Gepner-Witten depth rule.Comment: 16 pages, LaTe

    Surface Layers in General Relativity and Their Relation to Surface Tensions

    Full text link
    For a thin shell, the intrinsic 3-pressure will be shown to be analogous to -A, where A is the classical surface tension: First, interior and exterior Schwarzschild solutions will be matched together such that the surface layer generated at the common boundary has no gravitational mass; then its intrinsic 3-pressure represents a surface tension fulfilling Kelvin's relation between mean curvature and pressure difference in the Newtonian limit. Second, after a suitable definition of mean curvature, the general relativistic analogue to Kelvin's relation will be proven to be contained in the equation of motion of the surface layer.Comment: 12 pages, LaTeX, no figur

    Bures volume of the set of mixed quantum states

    Full text link
    We compute the volume of the N^2-1 dimensional set M_N of density matrices of size N with respect to the Bures measure and show that it is equal to that of a N^2-1 dimensional hyper-halfsphere of radius 1/2. For N=2 we obtain the volume of the Uhlmann 3-D hemisphere, embedded in R^4. We find also the area of the boundary of the set M_N and obtain analogous results for the smaller set of all real density matrices. An explicit formula for the Bures-Hall normalization constants is derived for an arbitrary N.Comment: 15 revtex pages, 2 figures in .eps; ver. 3, Eq. (4.19) correcte

    The Quantity Theory of Money is Valid. The New Keynesians are Wrong!

    Get PDF
    We test the quantity theory of money (QTM) using a novel approach and a large new sample. We do not follow the usual approach of first differentiating the logarithm of the Cambridge equation to obtain an equation relating the growth rate of real GDP, the growth rate of money and inflation. These variables must then again be ‘integrated’ by averaging in order to obtain stable relationships. Instead we suggest a much simpler procedure for testing directly the stability of the coefficient of the Cambridge equation. For 125 countries and post-war data we find the coefficient to be surprisingly stable. We do not select for high inflation episodes as was done in most empirical studies; inflation rates do not even appear in our data set. Much work supporting the QTM has been done by economic historians and at the University of Chicago by Milton Friedman and his associates. The QTM was a foundation stone of the monetarist revolution. Subsequently belief in it waned. The currently dominant New Keynesian School, implicitly or explicitly denies the validity of the QTM. We survey this history and argue that the QTM is valid and New Keynesians are wrong

    The Role of Strangeness in Astrophysics - an Odyssey through Strange Phases

    Get PDF
    The equation of state for compact stars is reviewed with special emphasis on the role of strange hadrons, strange dibaryons and strange quark matter. Implications for the properties of compact stars are presented. The importance of neutron star data to constrain the properties of hypothetic particles and the possible existence of exotic phases in dense matter is outlined. We also discuss the growing interplay between astrophysics and heavy-ion physics.Comment: invited talk given at Strange Quark Matter 2001, Frankfurt, Germany, 8 pages, uses iopart.cls, minor modifications, version to appear in J. Phys.

    ATPase activity in macula densa cells of the rabbit kidney

    Full text link
    Na-K- and Mg-activated ATPase activities were determined in maculae densae and glomeruli dissected from both superficial and juxtamedullary nephrons of normal rabbits, using an ultramicro method including a cycling reaction. Activities were expressed as P i generated per macula densa or per glomerulus and normalized for tissue volume. Results indicate that the mean volume of superficial and juxtamedullary macula densa samples was not statistically different, while glomeruli from deep nephrons had sample volumes that were 29% larger than those from superficial nephrons ( P <0.001). Correcting for volume both superficial and juxtamedullary macula densa samples had an Na-K-ATPase activity of 0.37±0.21 fmol · h −1 · (μm 3 ) −1 . Mg-ATPase activity in both pools was also similar [0.41±0.07 and 0.52±0.1 fmol · h −1 · (μm 3 ) −1 ]. Na-K-ATPase activity in macula densa cells is estimated to be about 1/40th the activity of surrounding cortical thick ascending limb cells. Total glomerular ATPase per unit volume was significantly higher in glomeruli from superficial than from deep nephrons [0.41±0.04 vs. 0.28±0.04 fmol · h −1 · (μm 3 ) −1 P <0.05]. There was no statistically significant activity of Na-K-ATPase in either superficial or deep glomeruli. These results suggest that in contrast to previous reports, the macula densa contains Na-K-ATPase, but at a low level relative to surrounding tubular cells. Further, in normal rabbits, this activity is invariant in superficial and juxtamedullary samples.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47454/1/424_2004_Article_BF00580725.pd

    Sustainable Human Development: Corporate Challenges and Potentials the Case of Bayer CropScience's Cotton Seed Production in Rural Karnataka (India)

    Get PDF
    This paper aims to explore concepts, methods and empirical results of potential impacts of Transnational Corporations (TNC) on Sustainable Human Development (SHD) in emerging market countries. In doing so, a further major goal is to explain, illustrate and discuss how the theoretical CA framework used in the GeNECA project2 can be applied to corporate SHD impacts. Our findings are based on the case of Bayer CropScience’s Model Village Project in rural Karnataka, India. To achieve our goals, we first establish a theoretical framework for assessing corporate impacts on SHD to capture SHD effects. Thereafter, we introduce the case of Bayer CropScience’s seed production in rural India, for which a “Model Village Project (MVP)” has been established to explore ways, potentials and challenges of promoting SHD of the villagers and corporate goals in a win-win-strategy. Afterwards, we explain methodological requirements, our representative database for the quantitative analyses, and the qualitative methods that we use for project evaluation. Based on findings of the authors’ external evaluation of the MVP, we discuss the baseline situation in the model villages with respect to corporate potentials, challenges and limitations to foster SHD impacts. Methodologically, we find the combination of quantitative representative methods and qualitative assessments to be most effective to capture corporate potentials and risks. Furthermore it turns out to be promising to extend the analyses beyond standardized benchmarks like the MDGs. We show that major determinants of SHD established in the paper result in a portfolio of corporate opportunities and risks. For instance, the reality of underemployment in the model villages provides specific corporate opportunities like an abundant pool of labor supply. However, it also produces corporate risks, e.g. lack of capital available for necessary investment by suppliers who frequently suffer from poverty, risk of over-indebtedness and a resulting inability to accumulate enough capital and to raise productivity. In the comprehensive opportunity and riskportfolio of this Bayer CropScience case, we find abundant potential business cases which we discuss further in the text. We conclude that corporate potentials as well as risks of corporate neglect and violations of people-centered SHD also depend on how much the villagers are enabled and empowered to make most of their agency as individuals and as groups. Furthermore, it depends on trust building as a prerequisite of awareness raising of the villagers themselves, so that they are willing and able to participate successfully in the undertaken procedures
    corecore