Carlos Mena

Role of access to parks and markets with anthropometric measurements, biological markers, and a healthy lifestyle

Background: This study examined the association between access to urban green spaces and markets with anthropometric measurements, biological markers, sociodemographic, and healthy lifestyle. Methods: Geographic information systems were used to establish a correlation between environmental features and cardiovascular risk parameters. A total number of 832 (age range 18–74 years) individuals were selected for this study. Results: Body mass index was significantly and positively related to the distance to parks (ρ = 0.079, p < 0.05), but negatively related to the distance to markets (ρ = −0.125, p < 0.05). In addition, waist circumference was similar and positively related to distance to parks (ρ = 0.097, p < 0.05) and negatively related to distance to markets (ρ = −0.092, p < 0.05). With respect to biochemical parameters, when there was an increase in the distance to markets, high-density lipoprotein cholesterol increased and glycemia decreased. Conclusion: The results of this study suggest the importance of the role of environmental factors such as parks and markets in the development of cardiovascular risk.

Efecto de la cobertura y de la fertilización en el desarrollo de plantas de Nothofagus alessandrii cultivadas en contenedor

Nothofagus alessandrii es una especie en peligro de extincion, de la cual aun no hay informacion suficiente sobre el cultivo de plantas en vivero. Por ello, el objetivo de este estudio fue analizar el efecto de la cobertura y de la fertilizacion en el desarrollo inicial de las plantas durante una temporada. Utilizando un diseno en parcelas divididas en bloques al azar, se ensayaron tres niveles de sombra (malla Raschel® de 35, 50, y 80 %) y tres dosis de fertilizante de entrega lenta (4, 6, y 10 g de Osmocote® por litro de sustrato). Los resultados muestran que hubo un efecto significativo de la sombra en el desarrollo de las plantas, observandose mejores atributos en plantas con 35-50 % de sombra, respecto de las cultivadas con 80 %. En general, la fertilizacion no afecto el desarrollo de las plantas. Se puede concluir que es mas eficiente cultivar plantas de N. alessandrii en vivero bajo una cobertura de 35 % de sombra y fertilizando con 4 g L-1. Asi, es posible producir, en promedio, plantas de 28 cm de longitud de tallo, 4 mm de diametro de cuello de la raiz, 3,2 g planta-1 de biomasa total e indices de calidad de 6,9 para el de esbeltez, 2,2 para el de tallo-raiz y 2,1 para el de Dickson.

Spatial analysis for the epidemiological study of cardiovascular diseases: A systematic literature search

Cardiovascular diseases (CVDs) are the primary cause of death and disability in de world, and the detection of populations at risk as well as localization of vulnerable areas is essential for adequate epidemiological management. Techniques developed for spatial analysis, among them geographical information systems and spatial statistics, such as cluster detection and spatial correlation, are useful for the study of the distribution of the CVDs. These techniques, enabling recognition of events at different geographical levels of study (e.g., rural, deprived neighbourhoods, etc.), make it possible to relate CVDs to factors present in the immediate environment. The systemic literature presented here shows that this group of diseases is clustered with regard to incidence, mortality and hospitalization as well as obesity, smoking, increased glycated haemoglobin levels, hypertension physical activity and age. In addition, acquired variables such as income, residency (rural or urban) and education, contribute to CVD clustering. Both local cluster detection and spatial regression techniques give statistical weight to the findings providing valuable information that can influence response mechanisms in the health services by indicating locations in need of intervention and assignment of available resources.

Spatial distribution and physical activity: implications for prevention of cardiovascular diseases

BackgroundThe current lifestyle of the population contributes to the development of cardiovascular diseases (CVD). Physical inactivity has become a major public health concern that is associated with increased risk of morbidity or worsening CVD risk factors. Studies have shown that the area of residence is associated with obesity and physical inactivity.AimsIn this context, it has been found that the tools of geomatics help to improve public health policies since through these it is possible to improve the environment-health relationship.MethodsPUBMED and ScienceDirect databases were searched.ResultsSpatial clustering techniques can identify high and low risk areas for physical activity and CVD risk factors. Thus, the highest levels of physical activity are concentrated in places where there is proximity to connecting areas, trails and high density of parks and green areas.ConclusionsTherefore, the application of geomatics will allow the development of methodologies for the registration of spatiotemporal characteristics of diseases related to different characteristics of people. The present article aims to highlight the relative contribution of spatial distribution on physical activity and its implications for prevention of CVD.

Impact of walkability with regard to physical activity in the prevention of diabetes

Walkability, a component of urban design intended to facilitate pedestrian traffic, depends on parameters associated with the connectivity of routes, population density and availability of destinations in the neighbourhood. The aim is to achieve levels of physical activity related to the prevention of risk factors associated with diseases, such as diabetes and the improvement of glycaemia control. It is important to consider that the effects of walkability depend on its relation with other variables present in the neighbourhood, e.g., environmental and socioeconomic factors. Considering this, improving walkability levels could be an effective strategy to reduce disease, the prevalence of diabetes in particular, in the population and thus reduce public spending. To investigate these relationships, PUBMED and ScienceDirect databases were searched using the following key words: Diabetes, Walkability and Physical activity.

Geographic clustering of elderly people with above-norm anthropometric measurements and blood chemistry

The global percentage of people over 60 is strongly increasing and estimated to exceed 20% by 20,150, which means that there will be an increase in many pathological conditions related to aging. Mapping of the location of aging people and identification of their needs can be extremely valuable from a social-economic point of view. Participants in this study were 148 randomly selected adults from Talca City, Chile aged 60-74 at baseline. Geographic information systems (GIS) analyses were performed using ArcGIS software through its module Spatial Autocorrelation. In this study, we demonstrated that elderly people show geographic clustering according to above-norm results of anthropometric measurements and blood chemistry. The spatial identifications found would facilitate exploring the impact of treatment programmes in communities where many aging people live, thereby improving their quality of life as well as reducing overall costs.

Caracterización y cuantificación de fragmentos de bosque nativo, en un sector del secano interior de la Región del Maule, Chile

Los bosques mediterraneos, en general, han sufrido altos grados de fragmentacion, principalmente por la accion antropogenica, consecuencia de las actividades productivas agro-ganaderas, asentamientos humanos y plantaciones forestales de especies exoticas de rapido crecimiento, derivando en una perdida en la continuidad de los bosques naturales, y, por ende, en una disminucion de la biodiversidad. En este contexto, el objetivo de este trabajo fue evaluar el potencial que tiene el uso de imagenes satelitales y los Sistemas de Informacion Geografica (SIG) para cuantificar y caracterizar la evolucion espacial de los bosques nativos, en un sector del secano interior de la Region del Maule, Chile. El estudio se realizo con imagenes Landsat-5 TM de los anos 2004 y 2008, que fueron clasificadas mediante el metodo supervisado donde fue necesario realizar tratamientos digitales previos, considerando correcciones atmosfericas y geometricas, para disminuir los errores de interpretacion y medicion. Dentro de los analisis, se incorporo informacion tematica digital de uso del suelo, obtenida desde la Corporacion Nacional Forestal (CONAF), y se integro, ademas, una de las tecnicas mas recientes derivada de teledeteccion espacial para el estudio de cambios en la cobertura terrestre, llamada Rotacion Controlada por Eje de No Cambio (RCEN). Finalmente, se estimaron indices de fragmentacion, con la finalidad de caracterizar la configuracion espacial del paisaje. A partir de los resultados de la clasificacion digital fue posible estimar metricas de paisaje que muestran diferencias importantes en la estructura del area estudiada entre los dos periodos. Ademas, se genero una imagen de cambio 2004/2008 que permitio evaluar la consistencia de la tecnica RCEN, demostrando la factibilidad de utilizar esta metodologia alternativa para la deteccion de cambios, en terminos de degradacion y recuperacion de masa boscosa.

Change detection in the semi-arid landscape using radiometric rotation applied to remote sensing data

The main task is to apply in the semi arid landscape of Maule region (Chile), the multi-temporal change detection algorithm ¿RCNA multi-spectral¿, using TM/Landsat images (2004 and 2008). The RCNA is based in angular parameters; those angles are calculated in function of the axis formed by the straight line of regression of those points labeled in the field survey as no-change. The image for detection was transformed from a continuous (floating-point) to thematic image, through a slicing and labeling process. Hence it is possible to discriminate: two classes related to degradation, two referring to regeneration and one of no-change. In the timeframe studied 4.6% of area under study presents degradation patterns, derived from the complete removal of the matorral type, followed by changes of land use. We found out that the application of multi-spectral RCNA technique in semi-arid landscape is sufficiently robust and the complex radiometric correction is not necessary.

Desarrollo de un Sistema de Información Geográfica para Mejorar la Gestión del Agua de Riego del Embalse Convento Viejo, Chile

espanolDentro del proceso de establecimiento de las lineas de desarrollo estrategico para la actividad agricola, la geomatica y sus diversas tecnologias permiten generar una caracterizacion altamente representativa y confiable del territorio, expresada en una base de datos digital dinamica y flexible, que propicia la planificacion y el seguimiento de los cambios productivos observados en los terrenos beneficiados con el incremento del agua de riego y el mejoramiento de su red de distribucion. El objetivo principal de la investigacion fue crear un Sistema de Informacion Geografica (SIG), alimentado con informacion base agropecuaria y socioeconomica, que permita la identificacion de sectores homogeneos de intervencion y el establecimiento de la tipologia de las explotaciones agricolas de las zonas directa o indirectamente beneficiadas con la construccion del Embalse Convento Viejo en su segunda etapa. La metodologia empleada considero la creacion de una base de datos digital a partir de la recopilacion y procesamiento de coberturas geograficas digitales de distintas fuentes y formatos, el geoprocesamiento de coberturas para identificar zonas homogeneas de intervencion, el diseno y aplicacion de una encuesta para tipificar las explotaciones agricolas, y la elaboracion de una interfase de consulta SIG. Se identificaron cuatro sectores geograficos homogeneos delimitados por variables topograficas y agroclimaticas. La tipologia de las explotaciones agricolas arrojo cuatro conglomerados (clusters) agrupados de acuerdo a variables sociales, productivas, financieras y comerciales. El SIG disenado permite consultar y analizar facilmente la informacion, mejorando la gestion y planificacion agricola. EnglishWhen establishing strategic lines for agricultural activities, geomatic and its diverse technologies allow generating a highly representative and reliable characterization of the territory, expressed in a dynamic and flexible digital data base. This helps the planning and monitoring of the productive changes observed in lands benefited with the increase of irrigation water and the improvement of its distribution network. The main goal of the investigation was to create a Geographic Information System (GIS), feed it with farming and socioeconomic information bases allowing the identification of homogeneous intervention sectors and the establishment of an agricultural exploitation typology of the zones directly or indirectly benefited by the construction of the ?Convento Viejo? Dam in its second stage. The methodology employed included the creation of a digital database from the compilation and processing of different sources and formats of digital geographic cover, geo-processing of the covers to identify homogenous intervention zones, design and application of a survey to classify the agricultural exploitations and the elaboration of a GIS consultation interphase. Four homogeneous geographic sectors were identified and delimited by topographic, agricultural and climatic variables. The agricultural exploitations typology resulted in four conglomerates (clusters) grouped according to social, productive, financial and commercial variables. The designed GIS allows easy consultation and analysis of the information and so improves agricultural management and planning.