Ingresos y bienes en la vejez, un acercamiento a la configuración de la seguridad económica de los adultos mayores mexiquenses

El propósito del artículo es establecer la conformación de la seguridad económica de la población adulta mayor mexiquense con base en las fuentes de ingreso y bienes a las que tiene acceso. Los resultados de la encuesta ESEDEM 2008 comprueban la hipótesis de que la seguridad económica está fuertemente relacionada con el perfil sociodemográfico del adulto mayor y muestra serias desventajas para los grupos que presentan características asociadas con mayores niveles de exclusión

Modelling of power electronics controllers for harmonic analysis in power systems

The research work presented in this thesis is concerned with the modelling of this new generation of power electronics controllers with a view to conduct comprehensive power systems harmonic analyses. An issue of paramount importance in this research is the representation of the self-commutated valves used by the controllers addressed in this work. Such a representation is based on switching functions that enable the realization of flexible and comprehensive harmonic models. Modularity is another key issue of great importance in this research, and the model of the voltage source converter is used as the basic building block with which to assemble harmonic models of actual power systems controllers. In this research the complex Fourier series in the form of operational matrices was used to derive the harmonic models. Also, a novel methodology is presented in this thesis for conducting transient analysis of electric networks containing non-linearities and power electronic components. The methodology is termed the extended harmonic domain. This method is based on the use of time-dependent Fourier series, operational matrices, state-space representation and averaging methods. With this method, state-space equations for linear circuit, non-linear circuits, and power electronics controllers models are obtained. The state variables are the harmonic coefficients of x(t) instead of x(t) itself. The solution of the state-space equations gives the dynamic response of the harmonic coefficients of x(t). Moreover, a new harmonic power flow methodology, based on the instantaneous power flow balance concept, the harmonic domain, and Newton-Raphson method, is developed and explained in the thesis. This method is based on the instantaneous power balance as opposed to the active and reactive power balance, followed by traditional harmonic power flow methods. The power system and the power electronics controllers are modelled entirely in the harmonic domain

The next-to-leading order vertex for a forward jet plus a rapidity gap at high energies

We present the results for the calculation of the forward jet vertex associated to a rapidity gap (coupling of a hard pomeron to the jet) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism at next-to-leading order (NLO). We handle the real emission contributions making use of the high energy effective action proposed by Lipatov, valid for multi-Regge and quasi-multi-Regge kinematics. This result is important since it allows, together with the NLO non-forward gluon Green function, to perform NLO studies of jet production in diffractive events (Mueller-Tang dijets, as a well-known example).Comment: 12 pages, some figure

Utilizacion de grasas de origen vegetal en raciones de vacas lecheras: rendimentos productivos, reproductivos y composición de la grasa

El objetivo del presente trabajo fue estudiar los efectos de la incorporación de aceites vegetales con distinto grado de saturación en raciones de vacas lecheras, sobre la producción, composición de la leche y de la grasa, y sobre los rendimientos reproductivos. Las raciones experimentales fueron: CONTROL (sin grasa añadida, TC), SOJA (con un 4% de aceite de soja en el concentrado, TS) y LINAZA (con un 4% de aceite de linaza en el concentrado, TL). La incorporación de aceite no afectó la producción de leche, pero redujo el contenido en grasa y proteína. Las raciones con aceite de SOJA y LINAZA presentaron un mayor contenido en ácido Vaccénico y CLA; y una mejor relación poli insaturados/saturados y n6/n3 que las raciones control. Las raciones con aceite de LINAZA dieron lugar a una mayor producción de leche al pico y tardaron menos días en alcanzar el pico de producción que las dietas CONTROL y SOJA. En general, la incorporación de aceite en las raciones dio lugar a una mejora significativa en los índices reproductivos

Development and validation of the competence in evidence based practice questionnaire (EBP-COQ) among nursing students

BACKGROUND: Nursing educators need rigorously developed instruments to assess competency in evidence based practice (EBP) at undergraduate level. This concept is defined as the capability to choose and use an integrated combination of knowledge, skills and attitudes with the intention to develop a task in a certain context. Also, we understand that EBP is gaining knowledge and skills, as well as increasing positive attitudes toward EBP that will promote a change in behaviour to implement EBP in practice. This study aims to develop a psychometric test of the Evidence Based Practice Evaluation Competence Questionnaire (EBP-COQ) among undergraduate nursing students. METHODS: The questionnaire was developed by item generation through a review of scientific literature and focus groups. The instrument was validated in terms of content validity through an expert review. The EBP-COQ was administered to a cohort of nursing students (n =100) to evaluate test reliability and select the best items. Psychometric properties of the final instrument were assessed in a sample of 261 nursing students. RESULTS: The EBP-COQ consisted of 25 items. A factorial analysis grouped the items into the three categories that define competence relating to EBP: attitude, knowledge and skills. Cronbach's alpha was 0.888 for the entire questionnaire. The factor solution explained 55.55% of the variance. CONCLUSIONS: EBP-COQ appears to measure with adequate reliability the attributes of undergraduate nursing students' competence in EBP. The instrument is quick to disseminate and easy to score, making it a suitable instrument for nursing educators to evaluate students' self-perceived competence in EBP.This work has been supported by a grant from FIS (Fondo de Investigación Sanitaria, Grant PI060913S

Genotoxicity and oxidative stress induced by cadmium and zinc in the planarian, Dugesia dorotocephala

This study sought to determine the DNA damage, and the lipoperoxidative effect, as well as changes in the superoxide dismutase (SOD) and catalase (CAT) activities induced by CdSO4 (Cd), and ZnSO4 (Zn), in addition to two different mixtures of the metals. Planarian Dugesia dorotocephala collected in the Ignacio Ramirez reservoir, México, adapted to laboratory conditions, and exposed to the metals in a controlled system was used. Initially, LC50 at 96 h of exposure was determined and the result obtained were 0.69 mg/L for Cd, 11.99 mg/L for Zn, 10.28 mg/L for mix 1, and 8.11 mg/L for mix 2. Then, the comet assay showed a DNA damage increase induced by Cd (0.13 and 0.2 mg/L) as high as 94% over the control level; the effect by Zn (from 0.2 to 2.7 mg/L) was clearly lower, although statistically significant with the high concentrations tested. As regards the two mixtures, we observed a concentration dependent increase. Similarly, in respect to lipoperoxidation, we found a strong effect by Cd, a slight effect by Zn, and a concentration dependent effect induced by the mixtures. Finally, the activity of the tested enzymes was modified by the metals in relation to the concentration applied.Keywords: Zinc, cadmium, planarian, DNA damage, oxidative stressAfrican Journal of Biotechnology Vol. 12(25), pp. 4028-403

Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor

Currently existing data show that the capability for long-chain PUFA (LC-PUFA) biosynthesis in teleost fish is more diverse than in other vertebrates. Such diversity has been primarily linked to the subfunctionalization that teleostei fatty acyl desaturase (Fads)2 desaturases have undergone during evolution. We previously showed that Chirostoma estor, one of the few representatives of freshwater atherinopsids, had the ability for LC-PUFA biosynthesis from C18 PUFA precursors, in agreement with this species having unusually high contents of DHA. The particular ancestry and pattern of LC-PUFA biosynthesis activity of C. estor make this species an excellent model for study to gain further insight into LC-PUFA biosynthetic abilities among teleosts. The present study aimed to characterize cDNA sequences encoding fatty acyl elongases and desaturases, key genes involved in the LC-PUFA biosynthesis. Results show that C. estor expresses an elongase of very long-chain FA (Elovl)5 elongase and two Fads2 desaturases displaying Δ4 and Δ6/Δ5 specificities, thus allowing us to conclude that these three genes cover all the enzymatic abilities required for LC-PUFA biosynthesis from C18 PUFA. In addition, the specificities of the C. estor Fads2 enabled us to propose potential evolutionary patterns and mechanisms for subfunctionalization of Fads2 among fish lineages

Perception of body image as indicator of weight status in the European union

Objective To identify the factors associated with an adequate perception of body image in relation to body weight. Material and methods An observational, cross-sectional study was conducted in a representative sample of the European Union (7155 men and 8077 women). Body Mass Index (BMI) was grouped into four categories, perceived body image was assessed using the nine silhouettes drawing scheme. A multivariable logistic regression model for each sex was used to adjust for potentially confounding variables. Results Underweight men and women classi®ed themselves better than other groups (92.9% of correct answers among men and 79.3% among women). Overall, women classi®ed themselves better than men (57.6% vs. 32.7%). Discussion Perceived body image as a method of assessment for body weight has different validity depending on sociodemographic or attitudinal categories. Perceived body image as an estimate of the nutritional status has a limited individualized application. Thus, perhaps it could be applied as a proxy measure of adiposity among slim males and among slim and overweight females, but not among the other groups

Regeneración post-incendio de Pinus pinaster Ait. en la Sierra de Guadarrama (Sistema Central, España): modelos descriptivos de los factores influyentes en la densidad inicial y la supervivencia

Natural regeneration of Pinus pinater after wildfire is quite irregular and depends on several unwellknown factors. The objective of this research work is to analyze said process in the forest fire which took place in summer 1999, affecting a total surface of 450 ha, in the Monte Abantos (Sierra de Guadarrama), located in the region of Madrid (Central Spain). This study was carried out in 50 permanent plots, 3 × 3 m size, over the following four years after the fire, collecting data about density, height, slenderness and mortality of the P. pinaster natural regeneration. The final results show that there are a large number of factors which affect seedlings emergency and mortality. A linear pattern that reveals the importance of germination layer physical properties (litter, outcrops and erosion), physiography and interspecific competition, has been obtained. According with the logistical pattern generated, interspecific competition is the most important factor to determine seedlings survival, although physiography, potential forest productivity, basal area, and erosion are also determinant.La regeneración natural post-incendio de Pinus pinaster es bastante irregular dependiendo de numerosos factores no bien conocidos. En este trabajo se pretende analizar dicho proceso en el incendio que tuvo lugar, el verano de 1999, en el Monte Abantos (Sierra de Guadarrama) de la Comunidad de Madrid (Sistema Central, España), con una superficie total afectada de 450 ha. El seguimiento de la densidad, la altura, la esbeltez y la mortalidad del regenerado de P. pinaster, durante los cuatro años siguientes al incendio, se ha llevado a cabo a través de 50 parcelas permanentes de 3 m × 3 m. Los resultados obtenidos revelan la existencia de un elevado número de factores que afectan a la emergencia y la mortalidad de las plántulas. Sí bien, se ha obtenido un modelo lineal que pone de manifiesto el papel fundamental en la emergencia de las características físicas del lecho de germinación (capa de hojarasca y mantillo, pedregosidad y afloramientos, y erosión), la fisiografía y la competencia interespecífica. A su vez este factor es el que más ha condicionado la supervivencia, según el modelo logístico generado, resultando también determinantes la fisiografía, la productividad potencial forestal, el área basal de la masa anterior al incendio y la erosión

Estimación del riesgo a la exposición de partículas suspendidas en el Valle de Toluca

Las partículas PM10 suspendidas en la atmósfera afectan el sistema respiratorio humano, además presentan un riesgo potencial cancerígeno debido a la gran cantidad de hidrocarburos que se quema en la atmósfera. Se estimó la exposición de las partículas PM10 suspendidas en el Valle de Toluca y sus alrededores, con la información de 8 años, proporcionada por la Red Automática Monitoreo de la Zona Metropolitana del Valle de Toluca (rama t). Para la estimación de riesgo se tomó en consideración la distribución de Gumbel-1 de Valores Extremos, asimismo se utilizaron diferentes periodos de retorno y la ocurrencia probabilística en intervalos de tiempo de 1, 5, 10, 12.5, 15, 17.5 y 20 años. Se infirió, estadísticamente, un alto grado de riesgo a la salud, debido a la magnitud de la concentración media de estas partículas y se predice que, de existir las condiciones actuales, esta relación estadística permanecerá invariante dentro de los próximos 20 años