Héctor Varela

Valoración multidimensional del envejecimiento en la ciudad de Antofagasta

BACKGROUND: The effects of aging on people must be evaluated to adequate sanitary actions. AIM: To assess the characteristics of older subjects living in Antofagasta, Chile. MATERIAL AND METHODS: Cross sectional assessment of 602 subjects without dementia, aged more than 60 years (55% females). A socioeconomic and medical history was obtained and Barthel, Lawton, Yesavage depression, Tromp fall risk and Folstein Mini mental scales were applied. RESULTS: Sixty eight percent of subjects had more than six years of studies. Forty six percent had hypertension, 28% had osteoarticular problems, 20% had hypercholesterolemia and 17% diabetes mellitus. Four percent had depression and falls were reported by 35%. Seventy four percent were independent in basic and instrumental activities. Ninety four percent had normal cognitive functions. Age was an important determinant of functional capacity. CONCLUSIONS: The main problems detected in this sample were the risk of falls and the presence of chronic diseases. Language: es

A new class of skew-symmetric distributions and related families

In this work, we investigate a new class of skew-symmetric distributions, which includes the distributions with the probability density function (pdf) given by g α(x)=2f(x) G(α x), introduced by Azzalini [A class of distributions which includes the normal ones, Scand. J. Statist. 12 (1985), pp. 171–178]. We call this new class as the symmetric-skew-symmetric family and it has the pdf proportional to f(x) G β(α x), where G β(x) is the cumulative distribution function of g β(x). We give some basic properties for the symmetric-skew-symmetric family and study the particular case obtained from the normal distribution.

On the Skew-Normal-Cauchy Distribution

In this article, we study further properties of a skew normal distribution, called the skew-normal-Cauchy (SNC) distribution by Nadarajah and Kotz (2003). A stochastic representation is obtained which allows alternative derivations for moments, moments generating function, and skewness and kurtosis coefficients. Issues related to singularity of the Fisher information matrix are investigated.

Evaluación experimental de la eficiencia de una pintura repelente para arañas del género Loxosceles

Loxosceles laeta (la arana de rincon), es la principal especie causante del cuadro de loxoscelismo en nuestro pais. Recientemente una pintura con propiedades repelentes ha sido promocionada comercialmente para la prevencion de este cuadro, no conociendose evidencias experimentales que demuestren su real efectividad. Por lo anterior se evaluo experimentalmente el efecto de la pintura frente a L. laeta . Ejemplares machos, hembras y ninfas de L. laeta , fueron depositados en habitaculos que permiten el desplazamiento de la arana con la mitad de su espacio con pintura repelente y la otra mitad sin pintar. Se observo diariamente por siete dias la frecuencia con que los aracnidos se encontraban en el espacio pintado o en el sin pintar. Estos experimentos fueron realizados en triplicado. La frecuencia de permanencia de los aracnidos sobre superficie recubierta con pintura repelente respecto de la observada sobre la superficie cubierta con pintura no repelente, no mostro diferencias estadisticamente significativas: 87,15 % versus 67,15% (ninfas); 72,85 % versus 77,14% (machos) y 91,42 % versus el 84,29% (hembras). Estos resultados sugieren que la pintura repelente, en las condiciones evaluadas, no cumple con tal funcion. Por lo anterior, las medidas de vigilancia y la educacion sanitaria de la poblacion continuan siendo las principales herramientas en la prevencion del loxoscelismo, mientras que la busqueda de nuevos compuestos con efecto repelente contra L. laeta pareciera ser una real necesidad.

TRICOMONOSIS EN ADOLESCENTES EMBARAZADAS DE ANTOFAGASTA, CHILE

RESUMEN Los problemas de salud de la adolescencia se caracterizan por una carga psicosocial elevada y un nivel de dano relativamente bajo en terminos de morbilidad y mortalidad, sin embargo, la disminucion de la edad promedio de la menarquia y el inicio precoz de actividad sexual coital son factores de riesgo para el embarazo y las enfermedades de transmision sexual (ETS) entre los adolescentes. En este trabajo se investigo la infeccion por Trichomonas vaginalis y los factores epidemiologicos y obstetricos relacionados entre 300 adolescentes embarazadas de la ciudad de Antofagasta, cuyas edades variaron entre 12 y 18 anos, de las cuales el 87,7 % se concentro en el rango 15 y 17 anos, en tanto que el 76,0 % tuvo su menarquia entre los 12 - 14 anos y el 27,3 % inicio su actividad sexual antes de los 15 anos. Se determino una tasa de infeccion por T. vaginalis de un 5,7 % .

Indicadores de fragilidad en adultos mayores del sistema público de salud de la ciudad de Antofagasta

BACKGROUND Frailty is not universal among older people but increases the risk of dependence. AIM To assess frailty among older people and its relationship with biological, psychological and social factors. MATERIAL AND METHODS Seven hundred fifty four older people aged 73 ± 6 years (61% females), attending a public primary care were assessed. Frailty was defined according to Fried criteria that considers inexplicable weight loss, tiredness, muscle weakness and lack of physical activity. RESULTS Absence of frailty, pre-frailty and frailty was found in 26, 69 and 5% of participants, respectively. Significant differences between frailty groups were observed for age, gender, years of studies, minimental and self-efficacy scores. Among participants defined as being in a pre-frail condition, 59% were non-disabled without risk and 41% non-disabled in risk, according to the functional assessment for older people used in Chilean primary care clinics. CONCLUSIONS Frailty among older people is associated with increasing age, education, cognitive status and self-efficacy.Background: Frailty is not universal among older people but increases the risk of dependence. Aim: To assess frailty among older people and its relationship with biological, psychological and social factors. Material and methods: Seven hundred fifty four older people aged 73 ± 6 years (61% females), attending a public primary care were assessed. Frailty was defined according to Fried criteria that considers inexplicable weight loss, tiredness, muscle weakness and lack of physical activity. Results: Absence of frailty, pre-frailty and frailty was found in 26, 69 and 5% of participants, respectively. Significant differences between frailty groups were observed for age, gender, years of studies, minimental and self-efficacy scores. Among participants defined as being in a pre-frail condition, 59% were non-disabled without risk and 41% non-disabled in risk, according to the functional assessment for older people used in Chilean primary care clinics. Conclusions: Frailty among older people is associated with increasing age, education, cognitive status and self-efficacy.

Melatonin Relations With Respiratory Quotient Weaken on Acute Exposure to High Altitude

High altitude (HA) exposure may affect human health and performance by involving the body timing system. Daily variations of melatonin may disrupt by HA exposure, thereby possibly affecting its relations with a metabolic parameter like the respiratory quotient (RQ). Sea level (SL) volunteers (7 women and 7 men, 21.0 ± 2.04 y) were examined for daily changes in salivary melatonin concentration (SMC). Sampling was successively done at SL (Antofagasta, Chile) and, on acute HA exposure, at nearby Caspana (3,270 m asl). Saliva was collected in special vials (Salimetrics Oral Swab, United Kingdom) at sunny noon (SMCD) and in the absence of blue light at midnight (SMCN). The samples were obtained after rinsing the mouth with tap water and were analyzed for SMC by immunoassay (ELISA kit; IBL International, Germany). RQ measurements (n = 12) were realized with a portable breath to breath metabolic system (OxiconTM Mobile, Germany), between 8:00 PM and 10:00 PM, once at either location. At SL, SMCD, and SMCN values (mean ± SD) were, respectively, 2.14 ± 1.30 and 11.6 ± 13.9 pg/ml (p < 0.05). Corresponding values at HA were 8.83 ± 12.6 and 13.7 ± 16.7 pg/ml (n.s.). RQ was 0.78 ± 0.07 and 0.89 ± 0.08, respectively, at SL and HA (p < 0.05). Differences between SMCN and SMCD (SMCN–SMCD) strongly correlate with the corresponding RQ values at SL (r = -0.74) and less tight at HA (r = -0.37). Similarly, mean daily SMC values (SMC) tightly correlate with RQ at SL (r = -0.79) and weaker at HA (r = -0.31). SMCN–SMCD, as well as, SMC values at SL, on the other hand, respectively, correlate with the corresponding values at HA (r = 0.71 and r = 0.85). Acute exposure to HA appears to loosen relations of SMC with RQ. A personal profile in daily SMC variation, on the other hand, tends to be conserved at HA.

Slashed generalized Rayleigh distribution

ABSTRACT We introduce a new family of distributions suitable for fitting positive data sets with high kurtosis which is called the Slashed Generalized Rayleigh Distribution. This distribution arises as the quotient of two independent random variables, one being a generalized Rayleigh distribution in the numerator and the other a power of the uniform distribution in the denominator. We present properties and carry out estimation of the model parameters by moment and maximum likelihood (ML) methods. Finally, we conduct a small simulation study to evaluate the performance of ML estimators and analyze real data sets to illustrate the usefulness of the new model.