On the minimum genus problem on bordered Klein surfaces

The minimum genus problem consists in determining the minimum algebraic genus of a surface on which a viven group G acts. For cyclic groups G this problem on bordered Klein surfaces was solved in 1989. The next step is to fix the number of boundary components of the surface and to obtain the minimum algebraic genus, and so the minimum topological genus. It was achieved for cyclic groups of prime and prime-power order in the nineties. In this work the corresponding results for cyclic groups of order N=pq, where p and q are different odd primes, is obtained. There appear different results depending on the orientability of the surface. Finally we obtain general results when the number of boundary components is small, which are valid for any odd N

Sobre grupos de automorfismos de superficies de Klein

El objetivo de esta memoria es el estudio de los grupos de automorfismos de las superficies de Klein, el concepto de superficie de Klein surge como extensión del de superficie de Riemann que resulta ser un caso particular. La técnica que hemos utilizado en el estudio de los grupos no euclídeos cristalográficos - grupos nec- que fueron estudiados por primera vez en Wilkie en 1966. Esta técnica permite no solo el estudio indicado en superficies de Klein sino también el de los automorfismos no orientables en superficies de Riemann

El género real de los grupos C2m ×Dn

Todo grupo finito G actúa como grupo de automorfismos de diversas superficies de Klein con borde. Al menor de los géneros algebraicos de estas superficies se le llama género real ρ(G) del grupo G. Se conocen todos los grupos con0 ≤ ρ(G) ≤ 8, ası como el género real para varias familias de grupos. En este trabajo calculamos el género real de los grupos 0 = C2m × Dn, en función delos números m y n

Fórmulas para polígonos hiperbólicos de ángulos rectos

En el polígono hiperbólico con todos los águlos rectos, se obtienen fórmulas explícitas parael coseno y el seno y el seno hiperbólicos de la longitud de un lado l en función de las longintudes de los N-3 lados dictintos a l y a sus adyacentes. También se obtiene la cotangente hiperbólica de los adyacentes en función de los mismos N-3 lados

Automorphism-Groups Of Real Algebraic-Curves Of Genus-3

Let C be an algebraic curve of genus 3, defined over the real field R. The automorphism group of C is studied in this paper. In a paper by the same authors [Mich. Math. J. 33, 55-74 (1986; see 20043 below)], the hyperelliptic case was solved, the authors found 5 abstract groups in that case. In the paper under review, a full classification is announced, in which 8 abstract groups appear. A sketch of one of the new cases is given, full proofs appeared in Mem. R. Acad. Cienc. Exactas Fis. Nat. Madrid, Ser. Cienc. Exactas 19 (1985; see the following review)]

Groups Of Automorphisms Of Hyperelliptic Klein Surfaces Of Genus 3

The order of a group of automorphisms of a compact Klein surface of genus 3 with boundary does not exceed 24 [see C. L. May, Pac. J. Math. 59, 199-210 (1975; Zbl 0422.30037)]. These groups of automorphisms are quotients of NEC groups of isometries of the hyperbolic plane since the Klein surface may be represented as the quotient of the hyperbolic plane by an NEC group. Being hyperelliptic places certain restrictions on the possible signatures of the corresponding NEC groups. By an exhaustive search starting with the finite groups of order less than 24 and using a variety of structural results on NEC groups (several proved in earlier papers by one or more of these authors) those finite groups which can occur as the full group of automorphisms of a hyperelliptic Klein surface of genus 3 are precisely determined. The fullness is exhibited by a simple argument on dimensions of Teichm¨uller spaces

Vascular NADH/NADPH oxidase is involved in enhanced superoxide production in spontaneously hypertensive rats

This study was designed to test the hypothesis that stimulation of nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NADH/NADPH) oxidase is involved in increased vascular superoxide anion (*O(2)(-)) production in spontaneously hypertensive rats (SHR). The study was performed in 16-week-old and 30-week-old normotensive Wistar-Kyoto rats (WKY(16) and WKY(30), respectively) and in 16-week-old and 30-week-old SHR (SHR(16) and SHR(30), respectively). In addition, 16-week-old SHR were treated with oral irbesartan (average dose 20 mg/kg per day) for 14 weeks (SHR(30)-I). Aortic NADH/NADPH oxidase activity was determined by use of chemiluminescence with lucigenin. The expression of p22phox messenger RNA was assessed by competitive reverse transcription-polymerase chain reaction. Vascular responses to acetylcholine were determined by isometric tension studies. Aortic wall structure was studied, determining the media thickness and the cross-sectional area by morphometric analysis. Whereas systolic blood pressure was significantly increased in the 2 groups of hypertensive animals compared with their normotensive controls, no differences were observed in systolic blood pressure between SHR(30) and SHR(16). No other differences in the parameters measured were found between WKY(16) and SHR(16). In SHR(30) compared with WKY(30), we found significantly greater p22phox mRNA level, NADH/NADPH-driven *O(2)(-) production, media thickness, and cross-sectional area and an impaired vasodilation in response to acetylcholine. Treated SHR had similar NADH/NADPH oxidase activity and p22phox expression as the WKY(30) group. The vascular functional and morphological parameters were improved in SHR(30)-I. These findings suggest that an association exists between p22phox gene overexpression and NADH/NADPH overactivity in the aortas of adult SHR. Enhanced NADH/NADPH oxidase-dependent *O(2)(-) production may contribute to endothelial dysfunction and vascular hypertrophy in this genetic model of hypertension

Sobre compactificaciones de Wallman-Frink de espacios discretos

Dado un espacio T3α (X,T), es posible obtener una compactificación T2 del mismo, mediante ultrafiltros asociados a ciertas bases distinguidas de cerrados de (X,T) (Frink [4]). Se plantea así el problema siguiente: ¿Puede obtenerse toda compactificación T2 de (X,T) por este método? Desde el año 1964 en que Frink lo planteó, este interrogante ha tenido respuestas afirmativas parciales. Sin embargo, la solución definitiva es negativa

Elementos de Matemáticas y aplicaciones

Material elaborado por profesores de la UCM para la asignatura de este nombre del grado en Ingeniería Matemáticas, el grado en Matemáticas y el grado en Matemáticas y Estadística. Contenidos: - Números enteros. Dígitos de control y criptografía. - Grupos de simetrías. Mosaicos. - Trigonometría plana y esférica. Aplicaciones (Navegación, Astronomía de posición, GPS). - Dinámica discreta. Aplicaciones (Finanzas, introducción al caos). - Teoría de grafos. Algoritmo de ordenación de Google

Body composition changes during a multidisciplinary treatment programme in overweight adolescents: EVASYON Study

Resumen Introducción: el principal objetivo de las intervenciones de pérdida de peso es disminuir la masa grasa manteniendo la masa libre de grasa. Objetivo: evaluar la efectividad de una intervención multidisciplinar en la composición corporal de adolescentes con sobrepeso, evaluados mediante diferentes métodos de composición corporal. Material y métodos: la intervención fue multidisciplinar sobre el estilo de vida, aplicada durante 13 meses. Los participantes eran adolescentes entre 13 y 16 años con sobrepeso y obesidad. Los adolescentes (n = 156; 54,8% mujeres) fueron evaluados mediante antropometría, absorciometría dual de rayos X y pletismografía por desplazamiento de aire. Todas las mediciones se realizaron al inicio, a los 2 y a los 13 meses. Se aplicaron análisis de la covarianza de medidas repetidas y la corrección de Bonferroni. Se realizó la imputación de las medidas antropométricas. Resultados: se logró una alta disminución significativa en el índice de masa grasa en los hombres después de 2 y 13 meses de intervención, según antropometría (1,16 y 1,56 kg/m2, respectivamente), absorciometría de rayos X (1,51 y 1,91 kg/m2) y pletismografía (2,13 y 2,44 kg/m2). Por otra parte, el mantenimiento a corto y largo plazo de la grasa y libre de grasa en el índice de masa fue observado por absorciometría de rayos X en las mujeres (0,94 y 0,68 kg/m2).Abstract Introduction: the main objectives of weight-loss interventions are to decrease fat mass while maintaining fatfree mass. Objective: our aim was to address effectiveness body composition changes in overweight adolescents assessed by different body composition methods following an obesity intervention programme. Material and methods: the life-style intervention was multi-disciplinary, with 13 months follow-up. Participants were 13-to-16 year-old overweight, or obese, Spanish adolescents. The adolescents (n = 156; 54.8% females) had body composition measured with anthropometry, dual-energy X-ray absorptiometry and air-displacement plethysmography. All measurements were made at baseline, and after 2- and 13-months. Repeated measures analysis of covariance to compare mean anthropometric changes over time and the Bonferroni correction were applied. Imputation of anthropometric measures was performed. Results: a high significant decrease in fat mass index was achieved in males after 2-and 13-months of intervention as measured by anthropometry (1.16 and 1.56 kg / m2, respectively), X-ray absorptiometry (1.51 and 1.91 kg / m2) and plethysmography (2.13 and 2.44 kg/m2). Moreover, a short and long-term maintenance of fat-and fat-free mass index was observed by X-ray absorptiometry in females (0.94 and 0.68 kg/m2)