1,305 research outputs found

    A bijection between unicellular and bicellular maps

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    In this paper we present a combinatorial proof of a relation between the generating functions of unicellular and bicellular maps. This relation is a consequence of the Schwinger-Dyson equation of matrix theory. Alternatively it can be proved using representation theory of the symmetric group. Here we give a bijective proof by rewiring unicellular maps of topological genus (g+1)(g+1) into bicellular maps of genus gg and pairs of unicellular maps of lower topological genera. Our result has immediate consequences for the folding of RNA interaction structures, since the time complexity of folding the transformed structure is O((n+m)5)O((n+m)^5), where n,mn,m are the lengths of the respective backbones, while the folding of the original structure has O(n6)O(n^6) time complexity, where nn is the length of the longer sequence.Comment: 18 pages, 13 figure

    The Splendid and the Savage: The Dance of the Opposites in Indigenous Andean Thought

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    One of the most well-known and defining characteristics of indigenous Andean thought is its adherence to a “complementary dualism” in which the “opposites” of existence are viewed as interdependent parts of a harmonious whole. This is in many ways in stark contrast to Western philosophical models, which have historically tended towards an “antagonistic dualism,” the view that the opposites are engaged in an eternal struggle for dominance. This paper considers how a culture’s relationship to the opposites—whether seen as a “war” or a “dance”—influences the way an individual creates psychological meaning. The results of my research into Andean complementary dualism are first presented. I then consider how this cultural-philosophical worldview compares to other complementary models, specifically that of G.W. Hegel and C. G. Jung. The paper concludes with a consideration of how the similar ideals of these complementary worldviews might inform the work of transpersonal researchers and practitioners

    Consumer Perceptions of Sustainable Farming Practices: A Best-Worst Scenario

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    This paper uses data collected in the summer and fall of 2010 from a national, web-based survey of 1002 households to initiate the process of examining consumer inferences and valuations of food products making "sustainably produced” claims. A Best-Worst scaling framework was implemented to identify what consumers believe “sustainably produced” labels mean and their preferences for each of the individual sustainable farming practices. The best-worst survey method forces respondents to make trade-offs by simultaneously choosing the most and least preferred attributes. The measured level of concern is then applied to a ratio scale. The ability of a firm to differentiate their product hinges critically on an accurate understanding of the perceptions consumers hold regarding what a credence labelling claim implies. Building upon existing work evaluating other food attribute labels (e.g., genetically-modified products, region of origin, use of growth hormones) and the impact of consumer inferences (e.g., implicit associations made from explicitly provided information), this work begins to address gaps in the literature regarding food products with “sustainably produced” claims.Sustainably Produced Food, Consumer Perceptions, Best-Worst, Agricultural and Food Policy, Consumer/Household Economics, Research Methods/ Statistical Methods, Q01, Q13, Q11,

    Timing and Determinants of Tuberculosis Treatment Interruption in Nairobi County, Kenya

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    Tuberculosis (TB) treatment is a key pillar in the management and control of TB. Service delivery within the treatment facilities plays an important role in ensuring treatment adherence by TB patients. A prospective cohort study involving 25 health facilities, 25 facility in-charge officers and 291 patients diagnosed as new sputum smear positive (SM+) between December 2014 and July 2015 was undertaken. The aim of the study was to estimate the median time to treatment interruption, associated factors and overall predictors of non-adherence to TB treatment. A total of 19 (6.5%) treatment interruptions were observed. The median time to default was 56 [95% CI, 36-105] days. Treatment in a non-public facility [AOR=0.210, 95% CI (0.046-0.952)] and facilities perceived to have adequate number of health care workers to offer Directly Observed Therapy (DOT) [AOR=0.195, 95% CI (0.068-0.56)] showed a lower odds of treatment interruption whereas attainment of secondary level education [AOR=5.28, 95% CI (1.18-23.59)] indicated a higher odds of treatment interruption. Non-clinical aspects of health care service delivery influence patient adherence to TB treatment. Health seeking behavior of groups considered to be high risk for treatment interruption should be incorporated into the design and delivery of TB treatment

    Effectiveness of zinc supplementation on diarrhea and average daily gain in pre-weaned dairy calves: A double-blind, block-randomized, placebo-controlled clinical trial.

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    The objective of this clinical trial was to evaluate the effectiveness of zinc supplementation on diarrhea and average daily weight gain (ADG) in pre-weaned dairy calves. A total of 1,482 healthy Holstein heifer and bull calves from a large California dairy were enrolled at 24 to 48 hours of age until hutch exit at approximately 90 days of age. Calves were block-randomized by time to one of three treatments: 1) placebo, 2) zinc methionine (ZM), or 3) zinc sulfate (ZS) administered in milk once daily for 14 days. Serum total protein at enrollment and body weight at birth, treatment end, and hutch exit were measured. Fecal consistency was assessed daily for 28 days post-enrollment. For a random sample of 127 calves, serum zinc concentrations before and after treatment and a fecal antigen ELISA at diarrhea start and resolution for Escherichia coli K99, rotavirus, coronavirus, and Cryptosporidium parvum were performed. Linear regression showed that ZM-treated bull calves had 22 g increased ADG compared to placebo-treated bulls (P = 0.042). ZM-treated heifers had 9 g decreased ADG compared to placebo-treated heifers (P = 0.037), after adjusting for average birth weight. Sex-stratified models showed that high birth weight heifers treated with ZM gained more than placebo-treated heifers of the same birth weight, which suggests a dose-response effect rather than a true sex-specific effect of ZM on ADG. Cox regression showed that ZM and ZS-treated calves had a 14.7% (P = 0.015) and 13.9% (P = 0.022) reduced hazard of diarrhea, respectively, compared to placebo-treated calves. Calves supplemented for at least the first five days of diarrhea with ZM and ZS had a 21.4% (P = 0.027) and 13.0% (P = 0.040) increased hazard of cure from diarrhea, respectively, compared to placebo-treated calves. Logistic regression showed that the odds of microbiological cure at diarrhea resolution for rotavirus, C. parvum, or any single fecal pathogen was not different between treatment groups. Zinc supplementation delayed diarrhea and expedited diarrhea recovery in pre-weaned calves. Additionally, zinc improved weight gain differentially in bulls compared to heifers, indicating a research need for sex-specific dosing

    A phase transition in energy-filtered RNA secondary structures

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    In this paper we study the effect of energy parameters on minimum free energy (mfe) RNA secondary structures. Employing a simplified combinatorial energy model, that is only dependent on the diagram representation and that is not sequence specific, we prove the following dichotomy result. Mfe structures derived via the Turner energy parameters contain only finitely many complex irreducible substructures and just minor parameter changes produce a class of mfe-structures that contain a large number of small irreducibles. We localize the exact point where the distribution of irreducibles experiences this phase transition from a discrete limit to a central limit distribution and subsequently put our result into the context of quantifying the effect of sparsification of the folding of these respective mfe-structures. We show that the sparsification of realistic mfe-structures leads to a constant time and space reduction and that the sparsifcation of the folding of structures with modified parameters leads to a linear time and space reduction. We furthermore identify the limit distribution at the phase transition as a Rayleigh distribution.Comment: 34 pages, 6 figure
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