6,080 research outputs found

    Kearney State College 1905-1980: A History of the first seventy-five years

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    History of Kearney State College, produced for the 75th anniversary of the institution.https://openspaces.unk.edu/spec-coll/1004/thumbnail.jp

    Counterexamples to the Low-Degree Conjecture

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    A conjecture of Hopkins (2018) posits that for certain high-dimensional hypothesis testing problems, no polynomial-time algorithm can outperform so-called "simple statistics", which are low-degree polynomials in the data. This conjecture formalizes the beliefs surrounding a line of recent work that seeks to understand statistical-versus-computational tradeoffs via the low-degree likelihood ratio. In this work, we refute the conjecture of Hopkins. However, our counterexample crucially exploits the specifics of the noise operator used in the conjecture, and we point out a simple way to modify the conjecture to rule out our counterexample. We also give an example illustrating that (even after the above modification), the symmetry assumption in the conjecture is necessary. These results do not undermine the low-degree framework for computational lower bounds, but rather aim to better understand what class of problems it is applicable to

    Schizoaffective disorder. How much belongs to schizophrenia? How much belongs to bipolar disorder?

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    Indexación: Web of Science; ScieloIntroducción: El Trastorno Esquizoafectivo constituye un área de controversias respecto a su nosología y criterios para su clasificación. Ha sido considerado como una variante de la Esquizofrenia, un cuadro mixto en el cual coexisten la Esquizofrenia y el Trastorno Bipolar y como un subtipo del Trastorno Bipolar. Método: Se revisan aspectos diagnósticos, clasificatorios y características psicopatológicas del trastorno en su concepción actual y aportes desde la perspectiva de la investigación neuropsicológica y la genética. Discusión y Conclusiones: El concepto actual de Trastorno Esquizoafectivo, difiere de su descripción original manteniéndose la falta de claridad definitiva respecto a su nosología. Tomando en consideración las alteraciones neurocognitivas que acompañan su evolución, el Trastorno Esquizoafectivo guardaría una mayor afinidad con las psicosis afectivas que con la Esquizofrenia. Desde la investigación genética surgen datos que cuestionan la distinción dicotómica clásica entre las psicosis afectivas y la Esquizofrenia establecida por E. Kraepelin, replanteándose la formulación de la psicosis en un continuum del cual el Trastorno Esquizoafectivo podría representar un estadio intermedio.Introduction: Schizoaffective Disorder represents a controversial clinical entity, in regard to nosology and classification criteria. It has been considered as a variant of Schizophrenia, as a mixed entity between Schizophrenia and Bipolar Disorder and as a Bipolar Disorder subtype Method: Classificatory, clinical issues, neuropsychology and genetics research contributions are reviewed. Discussion and Conclusion: Schizoaffective Disorder concept at present time, differs from its original description, maintaining lack of definitive clarity with respect to its nosology. Considering neurocognitive impairment within its course, Schizoaffective Disorder looks much closer to affective psychosis than to Schizophrenia. From genetic research field emerges data that challenge the classic dichotomist distinction between affective psychosis and Schizophrenia established by E. Kraepelin, raising again the question about thinking in psychosis as a continuum in which Schizoaffective Disorder could represent an intermediate state.http://ref.scielo.org/4rww3

    Cutting edges at random in large recursive trees

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    We comment on old and new results related to the destruction of a random recursive tree (RRT), in which its edges are cut one after the other in a uniform random order. In particular, we study the number of steps needed to isolate or disconnect certain distinguished vertices when the size of the tree tends to infinity. New probabilistic explanations are given in terms of the so-called cut-tree and the tree of component sizes, which both encode different aspects of the destruction process. Finally, we establish the connection to Bernoulli bond percolation on large RRT's and present recent results on the cluster sizes in the supercritical regime.Comment: 29 pages, 3 figure

    Global affordability of fluoride toothpaste

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    <p>Abstract</p> <p>Objective</p> <p>Dental caries remains the most common disease worldwide and the use of fluoride toothpaste is a most effective preventive public health measure to prevent it. Changes in diets following globalization contribute to the development of dental caries in emerging economies. The aim of this paper is to compare the cost and relative affordability of fluoride toothpaste in high-, middle- and low-income countries. The hypothesis is that fluoride toothpaste is not equally affordable in high-, middle- and low-income countries.</p> <p>Methods</p> <p>Data on consumer prices of fluoride toothpastes were obtained from a self-completion questionnaire from 48 countries. The cost of fluoride toothpaste in high-, middle- and low-income countries was compared and related to annual household expenditure as well as to days of work needed to purchase the average annual usage of toothpaste per head.</p> <p>Results</p> <p>The general trend seems to be that the proportion of household expenditure required to purchase the annual dosage of toothpaste increases as the country's per capita household expenditure decreases. While in the UK for the poorest 30% of the population only 0.037 days of household expenditure is needed to purchase the annual average dosage (182.5 g) of the lowest cost toothpaste, 10.75 days are needed in Kenya. The proportion of annual household expenditure ranged from 0.02% in the UK to 4% in Zambia to buy the annual average amount of lowest cost toothpaste per head.</p> <p>Conclusion</p> <p>Significant inequalities in the affordability of this essential preventive care product indicate the necessity for action to make it more affordable. Various measures to improve affordability based on experiences from essential pharmaceuticals are proposed.</p

    Defects and boundary layers in non-Euclidean plates

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    We investigate the behavior of non-Euclidean plates with constant negative Gaussian curvature using the F\"oppl-von K\'arm\'an reduced theory of elasticity. Motivated by recent experimental results, we focus on annuli with a periodic profile. We prove rigorous upper and lower bounds for the elastic energy that scales like the thickness squared. In particular we show that are only two types of global minimizers -- deformations that remain flat and saddle shaped deformations with isolated regions of stretching near the edge of the annulus. We also show that there exist local minimizers with a periodic profile that have additional boundary layers near their lines of inflection. These additional boundary layers are a new phenomenon in thin elastic sheets and are necessary to regularize jump discontinuities in the azimuthal curvature across lines of inflection. We rigorously derive scaling laws for the width of these boundary layers as a function of the thickness of the sheet
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