Suchergebnisse

In this article, the axial vibrations of a rod with a clamped end and the transversal vibrations of a cantilever beam, both with a time-dependent and non-harmonic force applied on their free ends, are analysed. These are problems in which the traction and the shear, for the rod and the beam, respectively, prescribed in the boundaries of the bodies vary with time. The problems can be solved by the method proposed by Mindlin and Goodman. However, it is usual to solve this problem by the classic variable-separation method (which does not properly fulfil the time-dependent boundary conditions). The displacements and the forces along the systems are derived from both cited methods, and the results are compared. These results highlight the importance of using the proper solution method for the vibration problems with time-dependent boundary conditions. ; Comisión Interministerial de Ciencia y Tecnología of the Spanish Government and to the Comunidad Autónoma de Madrid for partial support of this work through the research projects DPI2011-23191 and CCG10-UC3M-DPI-5596, respectively. ; Publicado

In this work, closed-form expressions for the buckling loads of weakened Timoshenko columns with different boundary conditions and shear force approaches (proportional to the bending rotation or to the total slope) are presented. The crack model used promotes discontinuities in both transversal displacements and rotation due to bending. To solve the buckling problem, the perturbation method is used, considering that the solutions for both the cracked and the uncracked columns are slightly different. This procedure leads to firstorder closed-form expressions for the buckling loads of the Timoshenko cracked column, which were compared with those found by directly solving the corresponding eigenvalue problem, establishing validity limits for these solutions. ; The authors would like to thank the Comisión Interministerial de Ciencia y Tecnología of the Spanish Government and to the Comunidad Autónoma de Madrid for partial support of this work through the research projects DPI2011-23191 and CCG10-UC3M-DPI-5596, respectively. ; Publicado

The natural frequencies of the flapwise bending vibrations of a nonuniform rotating nanocantilever has been calculated, considering the true spatial variation of the axial force due to the rotation. The area of the nanobeam cross section is assumed to change linearly. The problem has been formulated using the nonlocal Eringen elasticity theory and it was solved by a pseudo spectral collocation method based on Chebyshev polynomials. The effect of the nonlocal small scale, angular speed, nonuniformity of the sec tion and hub radius on the vibration behavior of the nanocantilever is discussed. ; The authors thank the Comisión Interministerial de Ciencia y Tecnología of the Spanish Government and to the Comunidad Autónoma de Madrid for partial support of this work through the Research Projects DPI2011 23191 and CCG10 UC3M DPI 5596, respectively. ; Publicado

(1) Background: There is a lack of data on the long-term training characteristics and performance markers of elite young female endurance athletes. The aim of this study was to present the training load (ECOs), as well as the evolution of the anthropometric values and performance of three elite U23 female triathletes over a season. (2) Methods: General training data and performance data relating to the swimming, cycling, and running legs of the 2021 season were described. The training intensity distribution (TID) was presented using the triphasic model, while the training load was based on the ECO model. An anthropometric analysis was also conducted in accordance with the ISAK standards. (3) Results: Triathletes increased their VO2max in cycling (6.9–10%) and running (7.1–9.1%), as well as their power and speed associated with the VO2max (7.7–8.6% in cycling and 5.1–5.3% in running) and their swimming speed associated with the lactate thresholds (2.6–4.0% in LT2 and 1.2–2.5% in LT1). The triathletes completed more than 10 h of weekly average training time, with peak weeks exceeding 15 h. The average TID of the three triathletes was 82% in phase 1, 6% in phase 2, and 12% in phase 3. A decrease in the sum of skinfolds and fat mass percentage was observed during the season in the three triathletes, although the last measurement revealed a stagnation or slight rise in these parameters. (4) Conclusions: The triathletes performed a combination of two training periodization models (traditional and block periodization) with a polarized TID in most of the weeks of the season. Improvements in performance and physiological parameters were observed after the general preparatory period as well as a positive body composition evolution throughout the season, except at the end, where the last measurement revealed stagnation or a slight decline. This study can be useful as a general guide for endurance coaches to organize a training season with female U23 triathletes.

Antecedentes/Objetivos: El impacto de la democracia en indicadores de mortalidad infantil, materna y en esperanza de vida ha sido demostrado. Objetivo: explorar la relación entre la democracia y la soberanía y seguridad alimentaria en Iberoamérica, considerando la riqueza de los países en 2012. Métodos: Estudio transversal ecológico, que utiliza el país como unidad de análisis sobre la relación entre el índice de libertad (como proxy de la democracia) y las variables de 1. Soberanía alimentaria: Bajo peso al nacer, desnutrición aguda y crónica infantil, % de población bajo la línea de pobreza; y 2. Seguridad alimentaria: prevalencia de subnutrición, acceso agua potable, suministro de proteínas promedio, y intensidad del déficit alimentario. Fuentes información: Estadísticas de Naciones Unidas, Banco Mundial, FAO, Freedom House. Todos los datos son referidos a 2012. Los países se estratificaron según su nivel de riqueza (Producto interior bruto-PIB) siguiendo la clasificación del Banco Mundial: baja, media, alta. También se clasificó la democracia en 3 categorías según Freedom House: países libres, medianamente libres y dictaduras. Se realizó un modelo de regresión lineal simple, y ajustado para controlar el efecto potencial de la riqueza del país. Resultados: El índice de libertad de los países estudiados, controlado por el PIB, se detecta asociado especialmente a la soberanía alimentaria. En concreto, se asocia a la desnutrición aguda infantil R2 = 49,8% (p = 0,02), desnutrición crónica infantil R2 = 51,4% (p = 0,04), y al % de población bajo la línea de pobreza R2 = 61,6% (p = 0,002). De los indicadores de seguridad alimentaria, solo el acceso al agua potable se detecta asociado R2 = 60,3% (p = 0,01), el consumo de proteínas promedio se asocia al índice de libertad, pero al controlar por el PIB se pierde la asociación. Conclusiones: La economía de los países Iberoamericanos pierde peso en la influencia sobre la seguridad y soberanía alimentaria al considerar su nivel de democracia. Este estudio muestra una fuerte asociación positiva de importantes condiciones como la desnutrición infantil y el acceso al agua potable con los derechos políticos y las libertades civiles, los cuales son políticamente modificables. ; Proyecto Prometeo. SENESCYT. Ecuador.

Fundamentos: Existe una gran diferencia entre el consumo de agua y las bebidas que contiene agua (bebidas carbonatadas, azucaradas, zumos o bebidas alcohólicas). El consumo de estas bebidas está relacionado con el desarrollo de enfermedades crónicas (obesidad, diabetes tipo 2, hipertensión arterial o dislipemias). El objetivo es determinar la frecuencia de consumo de bebidas de los estudiantes de la Universidad de Alicante. Métodos: Estudio transversal descriptivo. Población 26.273 estudiantes. Se seleccionaron 396 mediante muestreo aleatorio simple. Se utilizó un cuestionario frecuencia consumo para estimar la ingesta individual. Variables: bebidas (n=12) y frecuencia de consumo (n=4). Resultados: El 29,6% de hombres y el 13,0% de mujeres consumen bebidas carbonatadas con azúcar a diario (p-valor<0,001). El consumo diario de vino es nulo. El 41,4% de la población consume cerveza y destilados semanalmente. El 76,1% de hombres y el 58,7% de mujeres, consumen alcohol como mínimo una vez a la semana, p-valor=0,001. Conclusiones: Los resultados plantean la necesidad de estudios epidemiológicos que orienten el desarrollo de políticas nutricionales dirigidas a reducir el consumo de bebidas azucaradas y alcohólicas entre la población joven. Mediante un trabajo conjunto entre las autoridades gubernamentales, medios de comunicación, industria alimentaria y la sociedad en general. ; Background: There is a difference between drinking water and water-containing drinks (soft drinks, sugary juices or alcoholic beverages). The consumption of these beverages is related to the development of chronic diseases (obesity, type 2 diabetes, hypertension or dyslipidemia). The objective is to determine the frequency of consumption of different types of drinks of students at the University of Alicante. Methods: Descriptive cross-sectional study. From a population of 26,273 students, a sample of 396 was selected by simple random sampling. Frequency questionnaire was used to estimate beverage consumption, including as variables beverages (n = 12) and frequency of consumption (n = 4). Results: 29.6% of men and 13.0% of women consumed sugary soft drinks daily (p-value <0.001). Daily consumption of wine is null. The 41.4% of the population consumed beer and spirits weekly. 76.1% of men and 58.7% of women consumed alcohol at least once a week, p-value = 0.001. Conclusions: The results suggest the need for epidemiological studies to guide the development of nutrition policies aimed at reducing consumption of sugary drinks and alcohol among young people through a partnership between government authorities, media, food industry and society in general.

Some countries reached, in 2015, the Millennium Development Goal of reducing maternal mortality to 96 or less maternal deaths per 100,000 live births. Others, however, did not. This paper analyses the strength of the association between maternal mortality and each of the six components of Governance-a political determinant scarcely explored in the literature-in 174 countries. It was found that the greater the governance, the lower maternal mortality, independently of a country's wealth. We used all six indicators of the World Bank's Worldwide Governance Indicators Project in 2015: government effectiveness, regulatory quality, rule of law, control of corruption, voice and accountability, and political stability and absence of violence. Findings were encouraging as maternal mortality in low-income countries with higher government effectiveness and regulatory quality was similar to that of medium-income countries with lower government effectiveness and regulatory quality. To achieve the post-2015 sustainable development goal on preventable maternal mortality-which persists despite economic development-all governance dimensions are essential and represent interdependent cornerstones.

Some countries reached, in 2015, the Millennium Development Goal of reducing maternal mortality to 96 or less maternal deaths per 100,000 live births. Others, however, did not. This paper analyses the strength of the association between maternal mortality and each of the six components of Governance—a political determinant scarcely explored in the literature—in 174 countries. It was found that the greater the governance, the lower maternal mortality, independently of a country's wealth. We used all six indicators of the World Bank's Worldwide Governance Indicators Project in 2015: government effectiveness, regulatory quality, rule of law, control of corruption, voice and accountability, and political stability and absence of violence. Findings were encouraging as maternal mortality in low-income countries with higher government effectiveness and regulatory quality was similar to that of medium-income countries with lower government effectiveness and regulatory quality. To achieve the post-2015 sustainable development goal on preventable maternal mortality—which persists despite economic development—all governance dimensions are essential and represent interdependent cornerstones. ; Research reported in this publication was supported by the National Institute on Minority Health and Health Disparities of the National Institutes of Health under Award Number T37MD008647.

When looking at life expectancy (LE) by sex, women live longer than men in all countries. Biological factors alone do not explain gender differences in LE, and examining structural differences may help illuminate other explanatory factors. The aim of this research is to analyse the influence of gender inequality on the gender gap in LE globally. We have carried out a regression analysis between the gender gap in relativised LE and the UN Gender Inequality Index (GII), with a sensitivity analysis conducted for its three dimensions, stratified by the six World Health Organization (WHO) regions. We adjusted the model by taking into consideration gross national income (GNI), democratic status and rural population. The results indicated a positive association for the European region (ß=0.184) and the Americas (ß=0.136) in our adjusted model. Conversely, for the African region, the relations between gender equality and the LE gender gap were found to be negative (ß=-0.125). The findings suggest that in the WHO European region and the Americas, greater gender equality leads to a narrowing of the gender LE gap, while it has a contrary relationship in Africa. We suggest that this could be because only higher scores in the GII between men and women show health benefits. ; This work was supported by the UK Academy of Medical Sciences Global Challenges Research Fund Networking Grant under Grant ACP Ref No. 102292 'Punching above their weight: Building capacity for research on some countries have better life expectancies than predicted by national income.'