7,014 research outputs found

    Generalized Wilson Chain for solving multichannel quantum impurity problems

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    The Numerical Renormalization Group is used to solve quantum impurity problems, which describe magnetic impurities in metals, nanodevices, and correlated materials within DMFT. Here we present a simple generalization of the Wilson Chain, which improves the scaling of computational cost with the number of channels/bands, bringing new problems within reach. The method is applied to calculate the t-matrix of the three-channel Kondo model at T=0, which shows universal crossovers near non-Fermi liquid critical points. A non-integrable three-impurity problem with three bands is also studied, revealing a rich phase diagram and novel screening/overscreening mechanisms.Comment: 5 pages + 5 pages supplementary materia

    Growing Pains or Opportunities? A Customer Survey of Three Farmers\u27 Markets in One Rural Community

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    The continued growth of farmers\u27 markets is presenting new challenges to Extension. As the number of markets expands, how can Extension help those in the same community work together for mutual benefit? The study reported here examined similarities and differences among customers attending three different farmers\u27 markets within a single locality in Gettysburg, Pennsylvania. Based on 370 customer surveys, study results underscore the diversity of markets operating within the same community and provide insights into ways Extension might assist markets to work together to expand their shared customer base, increase revenues, and better serve local residents

    Controlling the uncontrolled: Are there incidental experimenter effects on physiologic responding?

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    The degree to which experimenters shape participant behavior has long been of interest in experimental social science research. Here, we extend this question to the domain of peripheral psychophysiology, where experimenters often have direct, physical contact with participants, yet researchers do not consistently test for their influence. We describe analytic tools for examining experimenter effects in peripheral physiology. Using these tools, we investigate nine data sets totaling 1,341 participants and 160 experimenters across different roles (e.g., lead research assistants, evaluators, confederates) to demonstrate how researchers can test for experimenter effects in participant autonomic nervous system activity during baseline recordings and reactivity to study tasks. Our results showed (a) little to no significant variance in participants' physiological reactivity due to their experimenters, and (b) little to no evidence that three characteristics of experimenters that are well known to shape interpersonal interactions-status (using five studies with 682 total participants), gender (using two studies with 359 total participants), and race (in two studies with 554 total participants)-influenced participants' physiology. We highlight several reasons that experimenter effects in physiological data are still cause for concern, including the fact that experimenters in these studies were already restricted on a number of characteristics (e.g., age, education). We present recommendations for examining and reducing experimenter effects in physiological data and discuss implications for replication

    Nutrient Digestibility of Condensed Algal Residue Solubles in Beef Cattle Fishing Diets

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    Condensed algal residue solubles (CARS) were evaluated in finishing cattle diets. Six treatments were evaluated (2 × 3 factorial arrangement), CARS inclusion in the diet at 0, 5, or 10% of diet dry matter with 0 or 20% wet distillers grains. Th e remainder of the diets consisted of 57.5– 87.5% dry rolled corn, 7.5% sorghum silage and 5% supplement. Increasing wet distillers grains in the diet had no effect on dry matter and organic matter intake but decreased dry matter and organic matter digestibility. Increasing CARS inclusion in the diet resulted in lower dry matter and organic matter intake with no effect on dry matter and organic matter digestibility. Replacing up to 10% dry rolled corn with CARS in diets with or without wet distillers grains had little effect on digestibility of finishing beef cattle diets

    Scaling algebras and pointlike fields: A nonperturbative approach to renormalization

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    We present a method of short-distance analysis in quantum field theory that does not require choosing a renormalization prescription a priori. We set out from a local net of algebras with associated pointlike quantum fields. The net has a naturally defined scaling limit in the sense of Buchholz and Verch; we investigate the effect of this limit on the pointlike fields. Both for the fields and their operator product expansions, a well-defined limit procedure can be established. This can always be interpreted in the usual sense of multiplicative renormalization, where the renormalization factors are determined by our analysis. We also consider the limits of symmetry actions. In particular, for suitable limit states, the group of scaling transformations induces a dilation symmetry in the limit theory.Comment: minor changes and clarifications; as to appear in Commun. Math. Phys.; 37 page

    Banking from Leeds, not London: regional strategy and structure at the Yorkshire Bank, 1859–1952

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    Industrial philanthropist Edward Akroyd created the Yorkshire Penny Savings Bank in 1859. Despite competition from the Post Office Savings Bank after 1861 and a serious reserve problem in 1911, it sustained his overall strategy to become a successful regional bank. Using archival and contemporary sources to build on recent scholarship illustrating how savings banks were integrated into local economies and the complementary roles of philanthropy and paternalism, we analyse an English regional bank's strategy, including an assessment of strategic innovation, ownership changes and management structure. This will demonstrate that the founder's vision continued, even though the 1911 crisis radically altered both strategy and structure
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