A Simple Fusion Mehtod for Image Time Series Based on the Estimation of Image Temporal Validity

High-spatial-resolution satellites usually have the constraint of a low temporal frequency, which leads to long periods without information in cloudy areas. Furthermore, low-spatial-resolution satellites have higher revisit cycles. Combining information from high- and low- spatial-resolution satellites is thought a key factor for studies that require dense time series of high-resolution images, e.g., crop monitoring. There are several fusion methods in the bibliography, but they are time-consuming and complicated to implement. Moreover, the local evaluation of the fused images is rarely analyzed. In this paper, we present a simple and fast fusion method based on a weighted average of two input images (H and L ), which are weighted by their temporal validity to the image to be fused. The method was applied to two years (2009-2010) of Landsat and MODIS (MODerate Imaging Spectroradiometer) images that were acquired over a cropped area in Brazil. The fusion method was evaluated at global and local scales. The results show that the fused images reproduced reliable crop temporal profiles and correctly delineated th e boundaries between two neighboring fields. The great est advantages of the proposed method are the execution time and ease of use, which allow us to obtain a fused image in less than five minutes

Evaluation of Disaggregation Methods for Downscaling MODIS Land Surface Temperature to Landsat Spatial Resolution in Barrax Test Site

Thermal infrared (TIR) data are usually acquired at a coarser spatial resolution (CR) than visible and near infrared (VNIR). Several disaggregation methods have been recently developed to enhance the TIR spatial resolution using VNIR data. These approaches are based on the retrieval of a relation between TIR and VNIR data at CR, or training of a neural network, to be applied at the fine resolution afterward. In this work, different disaggregation methods are applied to the combination of two different sensors in the experimental test site of Barrax, Spain. The main objective is to test the feasibility of these techniques when applied to satellites provided with no TIR bands. Landsat and moderate imaging spectroradiometer (MODIS) images were used for this work. Land surface temperature (LST) fromMODIS images was disaggregated to the Landsat spatial resolution using Landsat VNIR data. Landsat LST was used for the validation and comparison of the different techniques. Best results were obtained by the method based on a linear regression between normalized difference vegetation index (NDVI) and LST. An average RMSE = ±1.9 K was observed between disaggregated and Landsat LST fromfour different dates in a study area of 120 km

Thermal-infrared spectral and angular characterization of crude oil and seawater emissivities for oil slick identification

Previous work has shown that crude oil emissivity is lower than that of seawater in the thermal-infrared (TIR) spectrum. Thus, oil slicks cause an emissivity decrease relative to seawater in that region. The aim of this paper was to carry out experimental measurements to characterize crude oil and seawater emissivity spectral and angular variations. The results showed that crude oil emissivity is lower than seawater emissivity and essentially flat in the 8 - 13 μm atmospheric window. Crude oil emissivity has a marked emissivity decrease with angle (from 0.956±0.005 at 15º to 0.873±0.007 at 65º), even higher than that of seawater, and thus the seawater-crude emissivity difference increases with angle (from +0.030±0.007 at close-to-nadir angles up to +0.068±0.010 in average at 65º). In addition, the experimental results were checked by using the dual-angle viewing capability of the ENVISAT-AATSR images (i.e., 0º-22º and 53º-55º for nadir and forward views respectively), with data acquired during the BP Deepwater Horizon oil slick in 2010. The objective was to explore the applicability to satellite observations. Nadir-forward emissivity differences of +0.028 and +0.017 were obtained for the oil slick and surrounding clean seawater respectively. Emissivity differences between the seawater and oil slick were +0.035 and +0.046 for nadir and forward views respectively, in agreement with the experimental data. The increase of seawater-crude emissivity difference with angle gives significant differences for off-nadir observation angles, showing a new chance of crude oil slick identification from satellite TIR data

Impact of Land Cover Change Induced by a Fire Event on the Surface Energy Fluxes Derived from Remote Sensing

Forest fires affect the natural cycle of the vegetation, and the structure and functioning of ecosystems. As a consequence of defoliation and vegetation mortality, surface energy flux patterns can suffer variations. Remote sensing techniques together with surface energy balance modeling offer the opportunity to explore these changes. In this paper we focus on a Mediterranean forest ecosystem. A fire event occurred in 2001 in Almodóvar del Pinar (Spain) affecting a pine and shrub area. A two-source energy balance approach was applied to a set of Landsat 5-TM and Landsat 7-EMT+ images to estimate the surface fluxes in the area. Three post-fire periods were analyzed, six, seven, nine, and 11 years after the fire event. Results showed the regeneration of the shrub area in 6–7 years, in contrast to the pine area, where an important decrease in evapotranspiration, around 1 mm·day−1, remained. Differences in evapotranspiration were mitigated nine and 11 years after the fire in the pine area, whereas significant deviations in the rest of the terms of the energy balance equation were still observed. The combined effect of changes in the vegetation structure and surface variables, such as land surface temperature, albedo, or vegetation coverage, is responsible for these variations in the surface energy flux patterns

Hábitos alimentarios, imagen corporal y bienestar emocional: mens sana in corpore sano

From the time of ancient Rome, it was stated that physical exercise, added to a good diet, were the key to people’s mental well-being. Although the premise is still valid nowadays, young people do not seem to understand it, as being overweight is a real public health problem in this population subgroup. The objective is to know the university population eating habits, seeing how these are related to their body and their emotional well-being. It is hypothesized that those who have worse eating habits will suffer greater discomfort with their body image, in the same way that their mental well-being will be diminished. 600 university students (300 women and 300 men) filled out the Lifestyle and Health Questionnaire (Giménez-García and Ballester-Arnal, 2017). For this work where chosenthose items related to food, body image and mental health. People who take care of their diet have a greater satisfaction with their body ( 2 = 45.86; p smaller than .001). At the same time, people who are proud of their body image report a greater emotional well-being ( 2 = 35.02; p smaller than .001). Youth who define themselves as a fat person report worse mental health than thin or normal-weight people ( 2 = 17.26; p= .002), taking significantly less care of their diet ( 2 = 23.34; p smaller than .001). Emotional well-being, body image and diet care are closely related. A balanced diet not only improves physical health, but also increases mental health. Health and education professionals should encourage young people to improve their diet. This will improve both body satisfaction and emotional well-being.Ya desde la época de la antigua Roma se afirmaba que el ejercicio físico, sumado a una buena alimentación, eran la clave para el bienestar mental. Aunque a día de hoy la premisa sigue siendo válida, muchos jóvenes parecen no tenerlo claro, pues el sobrepeso es un problema de salud pública en este subgrupo poblacional. El objetivo es conocer los hábitos alimentarios de la población universitaria, viendo cómo estos se relacionan con su bienestar corporal y emocional. Se hipotetiza que quienes tengan peores hábitos alimentarios padecerán un mayor malestar con su imagen corporal, de la misma forma que su bienestar mental se verá mermado. La muestra está formada por un total de 600 sujetos universitarios(300 mujeresy 300 hombres). Los participantes rellenaron el Cuestionario de Estilo de Vida y Salud (Giménez-García y Ballester-Arnal, 2017), escogiendo para este trabajo aquellos ítems relacionados con la alimentación, la imagen corporal y la salud mental. Aquellas personas que cuidan más su alimentación gozan de una mayor satisfacción con su cuerpo ( 2=45.86; p menor que .001). Al mismo tiempo, los jóvenes que están más orgullosos de la imagen corporal reportan un mayor bienestar emocional ( 2=35.02; p menor que .001). Aquellas personas que se autodefinen como gruesas reportan peor salud mental que las delgadas o las que tienen un peso dentro de los parámetros de la normalidad ( 2=17.26; p= .002), llegando a cuidar significativamente menos su alimentación ( 2=23.34; p menor que .001). El bienestar emocional, la imagen corporal y el cuidado de la alimentación están estrechamente relacionados. Una dieta equilibrada no solo mejora la salud física, sino que también incrementa la salud mental. Desde los ámbitos de la salud y la educación se ha de concienciar a los jóvenes para mejorar la alimentación. De esta forma se mejorará tanto la satisfacción corporal como su bienestar emocional

Personas mayores en riesgo: uso del preservativo ante las infidelidades

Even though sexually transmitted infections are usually associated with early stages of development, current studies focus on the older population. However, limited efforts are related to this group, due to some aspects such as the invisibility of their sexuality. This is more frequent, when it comes to socially penalized behavior, as the case of infidelity. For this reason, this study analyzes condom use by older people, in the context of infidelity, as well as the role that psychological variables and new sexual contexts, such as the Internet, could play. For this, 244 people (47.5% men and 52.5% women), with an average age of 64.4 years (SD= 5.32), completed a battery of questionnaires on sexuality that evaluated attitudes and practices, as well as condom use. Firstly, 22% of people have been unfaithful to their partners and, only 25.9% of these people have used the condom systematically; 29.7% of men and 17.6% of women have it done (Chi2 =,885; p≤,347). In this context, those people who do not use condoms report a higher level of sexual arousal before physical stimuli (M=4,55, SD=1,83) than those who use it (M=3,36, SD=1,94) (t =-2.05, p≤,045) and a higher use of the Internet for sexual purposes. In particular, online sexual activities would explain 18% of the variance of condom use (F=11,32; p≤,001). Thus, our findings emphasize the importance of opening the coverage of preventive programs to the elderly population, as well as of studying new sexual scenarios such as online that may play an important role in risk behaviors.This project has been funded by the Dávalos Fletcher Foundation.Si bien las infecciones de transmisión sexual suelen relacionarse con etapas evolutivas tempranas, estudios recientes ponen el foco de atención en la población más mayor. Sin embargo, pocos esfuerzos centran su atención en dicho colectivo, entre otros motivos, por la propia invisibilización de su sexualidad. Esto ocurre todavía más, cuando se trata de conductas penalizadas socialmente, como sería el caso de la infidelidad. Por este motivo, el presente estudio busca analizar la conducta de uso del preservativo en personas mayores, en el contexto de la infidelidad, así como el papel que podrían jugar variables psicológicas y nuevos contextos sexuales, como internet. Para ello, 244 personas (47,5% hombres y 52,5% mujeres), con edad promedio de 64,4 años (DT=5,32), cumplimentaron una batería de cuestionarios sobre sexualidad en los que se abordaron actitudes y prácticas sexuales, así como el uso del preservativo. En primer término, se observa cómo el 22% de las personas han sido infieles a sus parejas y, únicamente, el 25,9% de estas personas ha utilizado el preservativo de manera sistemática; haciéndolo el 29,7% de los hombres y el 17,6% de las mujeres (Chi2=,885; p≤,347). En este contexto, aquellas personas que no usan preservativo informan un mayor nivel de excitación sexual ante estímulos físicos (M=4,55, DT=1,83) que las que lo usan (M=3,36, DT=1,94) (t=-2,05; p≤,045) y un mayor uso de internet con fines sexuales. En concreto,  las actividades sexuales online explicarían un 18% de la varianza del uso del preservativo (F=11,32; p≤,001). Así pues, nuestros hallazgos enfatizan la importancia de ampliar la cobertura de los programas preventivos a la población de personas mayores, así como de profundizar nuevos escenarios sexuales como el online que podría estar jugando un importante papel en las conductas de riesgo.Este proyecto ha sido financiado por la Fundación Dávalos Fletcher

Análisis del consumo de sustancias e indicadores de salud física y psicológica en hombres y mujeres jóvenes

Health is a biopsychosocial experience related to certain aspects such as lifestyles and well-being. However, this perspective has not always been studied with regard to both gender and physical and mental health indicators. Objective: to analyze the relationship between specific health habits (tobacco, alcohol and substance consumption) and the subjective perception of physical and mental well-being taking into account gender differences. Method: 600 university students (50% men; 50% women) completed an online questionnaireregarding Lifestylesand Health (Giménez-García and Ballester-Arnal, 2017). Results: 13.5% reported poor physical health (14% men and 13% women) and 17.7% poor mental health (18.3% men and 17% women).Regarding theconsumption of toxicsubstances, 14.7% of thesamplesmokes, 47% of thesample has been quite many times drunk and 34.2% of the sample has consumed other substances. More men than women have been drunk many times (X2=10.13; p=.017) and more men than women have ever used other substances (X2=8.08; p= .004). In general, there is no association between the consumption and abuse of tobacco, alcohol and other substances with the perception of mental or physical health by young people. In spite of there should be a certain relationship between lifestyles such as substance use and mental and physical health, many of these results have not been significant. Given that subjective perception of mental and physical health has been evaluated and objective indicators have not, this may be a resault of the low risk perception of young people, which leads them to carry out unhealthy behaviors without being aware of the consequences at the short term. In prevention programs it is essential to consider this lack of risk perception at young people.La salud es una experiencia biopsicosocial que se relaciona con ciertos aspectos como los estilos de vida y el bienestar. Sin embargo, esta perspectiva no siempre se ha estudiado atendiendo tanto al género como a indicadores de salud física y mental. Objetivo: analizar la relación entre hábitos de salud específicos (tabaco, alcohol y consumo de sustancias) y la percepción subjetiva de bienestar físico y mental, teniendo en cuenta las diferencias de género. Método: 600 universitarios (50% hombres; 50% mujeres) completaron un cuestionario online sobre Estilos de Vida y Salud (Giménez-García y Ballester-Arnal, 2017). Resultados: el 13,5% reporta una mala salud física (14% hombres y 13% mujeres) y el 17,7% una mala salud mental (18,3% hombres y 17% mujeres).En cuanto al consumo de sustancias tóxicas, el 14,7% de la muestra fuma, el 47% se ha emborrachado bastantes-muchas veces y el 34,2% ha consumido otras sustancias. Más hombres que mujeres se han emborrachado muchas veces (X2= 10,13; p= .017) y han consumido otras sustancias alguna vez (X2=8,08; p= ,004). En general, no existe una asociación entre el consumo y abuso de tabaco, alcohol y otras sustancias con la percepción de salud mental ni física por parte de los jóvenes. Así, aunque en teoría debería existir cierta relación entre estilos de vida como el consumo de sustancias y la salud mental y física, gran parte de estos resultados no han sido significativos. Dado que se ha evaluado percepción subjetiva de salud mental y física y no indicadores objetivos,  esto puede deberse a la baja percepción de riesgo de los jóvenes, lo que les lleva a la realización de conductas no saludables sin por ello ser conscientes de las consecuencias no fácilmente reconocibles a corto plazo. En los programas de prevención es fundamental considerar esta falta de percepción de riesgo entre los jóvenes