242 research outputs found

    Functionally Countable Spaces and Baire Functions

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    The concept of the distinguished sets is applied to the investigation of the functionally countable spaces. It is proved that every Baire function on a functionally countable space has a countable image. This is a positive answer to a question of R. Levy and W. D. Rice

    Lepton pair production by high-energy neutrino in an external electromagnetic field

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    The process of the lepton pair production by a neutrino propagating in an external electromagnetic field is investigated in the framework of the Standard Model. Relatively simple exact expression for the probability as the single integral is obtained, which is suitable for a quantitative analysis.Comment: 9 pages, LATEX, 2 PS figures, submitted to Modern Physics Letters

    Continuous selections of multivalued mappings

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    This survey covers in our opinion the most important results in the theory of continuous selections of multivalued mappings (approximately) from 2002 through 2012. It extends and continues our previous such survey which appeared in Recent Progress in General Topology, II, which was published in 2002. In comparison, our present survey considers more restricted and specific areas of mathematics. Note that we do not consider the theory of selectors (i.e. continuous choices of elements from subsets of topological spaces) since this topics is covered by another survey in this volume

    Multiple fixed point theorems for contractive and Meir-Keeler type mappings defined on partially ordered spaces with a distance

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    [EN] We introduce and study a general concept of multiple fixed point for mappings defined on partially ordered distance spaces in the presence of a contraction type condition and appropriate monotonicity properties. This notion and the obtained results complement the corresponding ones from [M. Choban, V. Berinde, A general concept of multiple fixed point for mappings defined on spaces with a distance, Carpathian J. Math. 33 (2017), no. 3, 275--286] and also simplifies some concepts of multiple fixed point considered by various authors in the last decade or so.This second author acknowledges the support provided by the Deanship of Scientific Research at King Fahd University of Petroleum and Minerals for funding this work through the projects IN151014 and IN141047.Choban, MM.; Berinde, V. (2017). Multiple fixed point theorems for contractive and Meir-Keeler type mappings defined on partially ordered spaces with a distance. Applied General Topology. 18(2):317-330. https://doi.org/10.4995/agt.2017.7067SWORD31733018

    Selections, Paracompactness and Compactness

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    In the present paper, the Lindelof number and the degree of compactness of spaces and of the cozero-dimensional kernel of paracompact spaces are characterized in terms of selections of lower semi-continuous closed-valued mappings into complete metrizable (or discrete) spaces.Comment: 23 page

    Nonharmonic Contributions To The High-Temperature Phonon Thermodynamics Of Cr

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    Phonon densities of states (DOSs) of body-centered cubic chromium were measured by time-of-flight inelastic neutron scattering at temperatures up to 1493 K. Density functional theory calculations with both quasiharmonic (QH) and anharmonic (AH) methods were performed at temperatures above the Néel temperature. Features in the phonon DOSs decrease in energy (soften) substantially with temperature. A Born–von Kármán analysis using fits to the experimental DOSs reveals a softening of almost 17% of the high-transverse phonon branch between 330 and 1493 K. The low-transverse branch changes by approximately half this amount. The AH calculations capture the observed behavior of the two transverse phonon branches, but the QH calculations give some inverted trends. Vibrational entropies from phonons and electrons are obtained, and their sum is in excellent agreement with the entropy of chromium obtained by calorimetry, indicating that above 330 K, no explicit temperature-dependent magnetic contributions are necessary

    Diffuse Inelastic Neutron Scattering from Anharmonic Vibrations in Cuprite

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    Atomic vibrational dynamics in cuprite, Cu2O, was studied by inelastic neutron scattering and molecular dynamics (MD) simulations from 10 K to 900 K. Above 300 K, a diffuse inelastic intensity (DII) appeared, obscuring the high-energy phonon modes. Classical MD simulations with a machine learning interatomic potential reproduced general features of the DII, especially with a Langevin thermostat. The DII originates from random phase shifts of vibrating O-atoms that have anharmonic interactions with neighboring Cu-atoms

    Bariatric surgery: evidence-based practical recommendations

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    [Resumen] La obesidad mórbida es, habitualmente, refractaria a los tratamientos convencionales, por lo que la modificación de hábitos dietéticos y de actividad física y/o el uso de fármacos consiguen pérdidas de peso parciales con habitual recuperación posterior. La cirugía bariátrica constituye una opción terapéutica para los casos de obesidad con elevado índice de masa corporal (IMC) asociada a comorbilidades, con buenos resultados a corto y largo plazo. El Grupo de Trabajo sobre Obesidad de la Sociedad Española de Endocrinología y Nutrición (GOSEEN) ha elaborado un documento con recomendaciones prácticas basadas en la evidencia para el tratamiento quirúrgico de la obesidad. La revisión se estructura en 3 partes. En la primera se definen los conceptos de obesidad y comorbilidades asociadas, los tratamientos médicos y sus resultados, las indicaciones y contraindicaciones para el tratamiento quirúrgico con los criterios de selección de los pacientes, el manejo pre y perioperatorio y la valoración de grupos especiales, como adolescentes y personas de edad avanzada. En la segunda parte se describen las distintas técnicas quirúrgicas, las vías de acceso y los resultados comparativos, las complicaciones tanto a corto como a largo plazo, la repercusión de la pérdida ponderal sobre las comorbilidades y los criterios para evaluar la efectividad de la cirugía. En la tercera parte se desarrolla el seguimiento postoperatorio, el control dietético en fases tempranas y más tardías tras la cirugía, y el calendario de control médico y analítico con la suplementación de los distintos macro y micronutrientes en función de la técnica quirúrgica empleada. Se incluye un apartado final sobre gestación y cirugía bariátrica, así como tablas y gráficos complementarios al texto desarrollado. La cirugía bariátrica sigue siendo un tratamiento discutido para la obesidad, pero los resultados en la corrección del exceso ponderal con mejoría en las patologías asociadas y en la calidad de vida confirman que puede ser el tratamiento de elección en pacientes seleccionados, con la técnica quirúrgica apropiada y con un correcto control pre y postoperatorio.[Abstract] Morbid obesity is usually refractory to conventional treatments. Consequently, weight that is lost by modifying diet and exercise and/or the use of drugs is usually later regained. Bariatric surgery constitutes a therapeutic option in obese patients with a high body mass index associated with comorbidities and achieves good results in both the short and the long term. The Obesity Working Group of the Spanish Society of Endocrinology and Nutrition has produced a document with practical, evidencebased recommendations for the surgical treatment of obesity. The review is structured in three parts. The first part defines the concepts of obesity and associated comorbidities, medical treatments, their results, and the indications and contraindications for surgical treatment, as well as the criteria for patient selection, pre- and perisurgical management, and assessment of special groups such as adolescents and the elderly. The second part discusses the different surgical techniques, approaches and comparative results, short- and long-term complications, the repercussions of weight loss on comorbidities, and the criteria for assessing the effectiveness of surgery. The third part discusses postsurgical follow-up, dietary control in the early and subsequent stages after surgery and the schedule for medical and laboratory follow-up, together with the different macro- and micronutrient supplements that should be used depending on the surgical technique employed. A final section is included on pregnancy and bariatric surgery, as well as tables and figures that complement the text. Although bariatric surgery continues to be a questionable treatment for obesity, the results correcting excess weight, with improvements in associated comorbidities and in quality of life, confirm that this option could be the treatment of choice in selected patients when the appropriate surgical technique and correct preand postoperative follow-up are employed

    Underweight is independently associated with mortality in post-operative and non-operative patients admitted to the intensive care unit: a retrospective study

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    BACKGROUND: Low and high body mass index (BMI) have been recently shown to be associated with increased and decreased mortality after ICU admission, respectively. The objective of this study was to determine the impact of BMI on mortality and length of stay in patients admitted to the intensive care unit (ICU). METHODS: In this retrospective cohort study, the Acute Physiology and Chronic Health Evaluation (APACHE) III database of patients admitted to the ICUs of a tertiary academic medical center, from January 1997 to September 2002, was crossed with a Hospital Rule-based Systems database to obtain the height and weight of the patients on admission to the ICU. The cohort was divided in post-operative and non-operative groups. We created the following five subgroups based on the BMI: <18.5, 18.5 to 24.9, 25 to 29.9, 30.0 to 39.9, ≥ 40.0 Kg/m(2). A multiple logistic regression analysis was used to determine the independent impact of BMI on hospital mortality. The ICU length of stay ratio was defined as the ratio of the observed to the predicted LOS. P-value < 0.05 was considered significant. The 95% confidence interval (CI) was calculated for the odds ratio (OR). RESULTS: BMI was available in 19,669 of the 21,790 patients in the APACHE III database; 11,215 (57%) of the patients were admitted post-operatively. BMI < 18.5 was associated with increased mortality in both post-operative (OR = 2.14, 95% CI, 1.39 to 3.28) and non-operative (OR = 1.51, 95% CI, 1.13 to 2.01) patients. Post-operative patients with a BMI between 30.0 to 39.9 had a lower mortality rate (OR = 0.68, 95% CI, 0.49 to 0.94). Post-operative patients with BMI <18.5 or BMI ≥ 40 had an ICU length of stay ratio significantly higher than patients with BMI between 18.5 to 24.9. The addition of BMI < 18.5 did not improve significantly the accuracy of our prognostic model in predicting hospital mortality. CONCLUSIONS: Low BMI is associated with higher mortality in both post- and non-operative patients admitted to the ICU. LOS is increased in post-operative patients with low and high BMIs
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