Detección automática de planos de rueda de ferrocarril mediante tratamiento digital de imágenes empleando la Transformada de Hilbert

El presente artículo muestra una técnica basada en el tratamiento digital de imágenes, para diagnosticar planos de rueda de ferrocarril, para ello: se han extraido todos los picos de la señal; se ha hecho uso del concepto de señal analítica cuya parte real es la propia señal, es decir cada pico de la señal adquirida, y su parte imaginaria es la transformada de Hilbert de la señal original; se ha efectuado la representación de Lissajous de la señal analítica, de esa representación se ha obtenido una imagen a la que se aplican técnicas para la extracción de características de forma y contenido de regiones de pixeles; la selección de estas se ha llevado a cabo mediante búsqueda heurística empleando una función de evaluación basada en matrices de dispersión y su clasificación se ha realizado mediante aprendizaje supervisado empleando una Máquina de Vectores Soporte (MVS), utilizando la validación cruzada para la obtención de sus parámetros óptimos

GrabCut-Based Human Segmentation in Video Sequences

In this paper, we present a fully-automatic Spatio-Temporal GrabCut human segmentation methodology that combines tracking and segmentation. GrabCut initialization is performed by a HOG-based subject detection, face detection, and skin color model. Spatial information is included by Mean Shift clustering whereas temporal coherence is considered by the historical of Gaussian Mixture Models. Moreover, full face and pose recovery is obtained by combining human segmentation with Active Appearance Models and Conditional Random Fields. Results over public datasets and in a new Human Limb dataset show a robust segmentation and recovery of both face and pose using the presented methodology

Desgaste profesional, satisfacción y desempeño laboral en equipos de atención integral en situaciones de violencia a la mujer y familia

La presente investigación tuvo como objetivo determinar la influencia del desgaste profesional en la satisfacción y el desempeño laboral en Equipos de Atención Integral en situaciones de violencia a la Mujer y Familia. La metodología a usar fue de enfoque cuantitativo, no experimental y de corte transversal, de diseño correlacional, se usó una muestra de 52 profesionales. Se usaron los cuestionarios de desgaste profesional de la OIT, satisfacción laboral y desempeño laboral. Los resultados indican que existe influencia negativa de magnitud moderada (.34 ≤ r2 < .68) y estadísticamente significativa (p<.05) del desgaste profesional sobre la satisfacción laboral y además una influencia negativa de magnitud moderada (.34 ≤ r2 < .68) y estadísticamente significativa (p<.05) del desgaste profesional sobre el desempeño laboral de los miembros de los equipos de atención integral para casos de violencia de Trujillo. Se puede concluir que a mayor desgaste exista en los profesionales menor satisfacción laboral tendrán y menor desempeño labora en la realización de sus atenciones a usuarias víctimas de violencia familiar

Influence of the production method on the thermophysical properties of high temperature molten salt-based nanofluids

The potential use of molten salt-based nanofluids as thermal energy storage material in Concentrated Solar Power plants has gained attention over the last years due to their enhanced storage capacity. The possible effects of the salt-based nanofluid production at industrial scale have not been yet investigated, as this could influence the nanoparticles agglomeration and therefore their thermal and flow properties. Four methods were evaluated for the production of solar salt-based nanofluids containing 1 wt% of silica nanoparticles. The particle size distribution, the stability, the rheological behaviour and the specific heat of the samples were measured. Nanofluids prepared by means of a dry mixing method presented the lowest viscosity, trimodal particle size distribution and lack of stability. The commonly used dissolution method coupled with oven drying in a petri dish as well as the ball milling method presented non-Newtonian behaviour and intermediate values of particle size and stability. The new spray drying method proposed provided a monomodal particle size distribution with high stability but the highest viscosity and shear thickening behaviour. Results suggest that the four methods evaluated are appropriate for specific heat enhancement (up to 21.1%) but a commitment between stability and viscosity has to be achieved

Síntesis y caracterización de polímeros conductores basados es polipirrol PPY con dopaje de aleaciones DBS y PSS

En el presente trabajo de grado se presenta el desarrollo de un potenciostato para ciclovoltametría y se presenta la síntesis y caracterización de los siguientes materiales en forma de películas delgadas por medio de voltametría cíclica a potencial constante: polipirrol (PPY); polipirrol dopado con poliestireno sulfonato de sodio (PPY/PSS); polipirrol dopado con ácido dodecil benceno sulfónico (PPY/ DBS); y polipirrol dopado con poliestireno sulfonato de sodio y ácido dodecil benceno sulfónico (PPY/PSS-DBS). Los materiales sintetizados son considerados polímeros conductores con potencial aplicación en el desarrollo de músculos artificiales. Adicionalmente, se comparó la respuesta de cada material desarrollado por medio de voltametría cíclica a diferentes velocidades de barrido (5, 10, 25, 50, 75, 100 mV/s). Finalmente, el nuevo material desarrollado, correspondiente al polipirrol dopado con poliestireno sulfonato de sodio y ácido dodecil benceno sulfónico (PPY/PSS-DBS), fue caracterizado por medio de voltametría cíclica a diferentes velocidades de barrido, variación del límite catódico de potencial, variación de temperatura, variación de concentración del electrolito, y respuesta al número de ciclos.In this research, the development of a potentiostat for cyclovoltammetry is presented and the synthesis and characterization of the following materials in the form of thin films by means of constant potential cyclic voltammetry is presented: polypyrrole (PPY); polypyrrole doped with sodium polystyrene sulfonate (PPY/PSS); polypyrrole doped with dodecyl benzene sulfonic acid (PPY/DBS); and polypyrrole doped with sodium polystyrene sulfonate and dodecyl benzene sulfonic acid (PPY/PSS-DBS). The synthesized materials are considered conductive polymers with potential application in the development of artificial muscles. In addition, the response of each material developed by means of cyclic voltammetry at different scan rates (5, 10, 25, 50, 75, 100 mV/s) was compared. Finally, the new material developed, corresponding to polypyrrole doped with sodium polystyrene sulfonate and dodecyl benzene sulfonic acid (PPY/PSS-DBS), it was characterized by cyclic voltammetry at different scan rates, variation of the cathodic potential limit, variation of temperature, variation of electrolyte concentration, and response to the number of cycles

Optical characterisation and photothermal conversion efficiency of a water-based carbon nanofluid for direct solar absorption applications.

Carbon nanoparticles are very useful in solar thermal applications as they absorb much of the solar spectrum and can be inexpensive. Water-based carbon nanofluids with two different concentrations (3 and 33 mg l−1) were prepared with sodium dodecyl sulphate as surfactant to achieve good high-temperature stability with a constant mean particle size of 200 nm at 25 °C and 85 °C. The morphology of the nanoparticles was observed by Transmission Electron Microscopy and the particle size distribution was studied using Dynamic Light Scattering at room and high temperature. Ballistic transmittance, absorption coefficient and scattering albedo of the three fluids were measured by a spectrophotometer with and without an integrating sphere using the Kubelka-Munk theory. The average value of the absorption coefficient showed important increases when comparing water against the nanofluid with the highest concentration (from 0.1 to 3.3 cm−1). Finally, the temperature change achieved when lighting the samples with an artificial sunlight simulator were measured and photothermal conversion efficiencies were evaluated, with increases of up to 200% when comparing nanofluid and base fluid. The results of this study show this kind of nanofluids to be very interesting for increasing the overall efficiency of the direct absorber solar collectors

Language and Cultural Barriers and Facilitators of Sexual and Reproductive Health Care for Migrant Women in High-Income European Countries: An Integrative Review

Introduction: Dealing with intercultural communicative barriers in European countries' national health services is an increasing and necessary challenge to guarantee migrant women's right to health care. This integrative review describes the communication barriers and facilitators that migrant women encounter to access and use sexual and reproductive health (SRH) services in Europe. Methods: A literature search was performed to identify original studies in PubMed, CINAHL, PsycINFO, Web of Science, and Scopus, using keywords associated with migrant women and SRH services. This was supplemented by scanning the reference lists from relevant studies and similar reviews. Studies exploring the perspective of migrant women about communication barriers and facilitators to the access and use of SRH services were included, whereas those that solely explored health professional's experiences were excluded. Findings were organized into 4 themes: (1) verbal-linguistic barriers, (2) nonverbal language barriers, (3) cultural barriers, and (4) communication facilitators. Results: Nineteen studies met the inclusion criteria. Results showed that when women had problems understanding or being understood by health professionals, they experienced feelings of anxiety, fear, insecurity, and discrimination that discouraged them from using SRH services. The most requested facilitators by women were health education, access to professional interpreters and translation of written information, and increasing the practitioners' cultural competence. Discussion: Communication barriers undermine migrant women's right to benefit from preventive SRH programs and to make informed decisions concerning their health. It is necessary to establish tailored plans in each health care center to improve intercultural communication that integrate facilitators proposed by women. Future research should provide solid evidence on the effectiveness of each facilitator implemented

Detection of Seagrass Distribution Changes from 1991 to 2006 in Xincun Bay, Hainan, with Satellite Remote Sensing

Seagrass distribution is a very important index for costal management and protection. Seagrass distribution changes can be used as indexes to analyze the reasons for the changes. In this paper, in situ hyperspectral observation and satellite images of QuickBird, CBERS (China Brazil Earth Resources Satellite data) and Landsat data were used to retrieve bio-optical models and seagrass (Enhalus acoroides, Thalassia hemperichii) distribution in Xincun Bay, Hainan province, and seagrass distribution changes from 1991 to 2006 were analyzed. Hyperspectral results showed that the spectral bands at 555, 635, 650 and 675 nm are sensitive to leaf area index (LAI). Seagrass detection with QuickBird was more accurate than that with Landsat TM and CBERS; five classes could be classified clearly and used as correction for seagrass remote sensing data from Landsat TM and CBERS. In order to better describe seagrass distribution changes, the seagrass distribution area was divided as three regions: region A connected with region B in 1991, however it separated in 1999 and was wholly separated in 2001; seagrass in region C shrank gradually and could not be detected in 2006. Analysis of the reasons for seagrass reduction indicated it was mainly affected by aquaculture and typhoons and in recent years, by land use changes

Assessing Community Health Workers perceptions of their participation in COVID-19 related projects implemented throughout South Texas and their alignment to the Dimensions of Community Capacity

Background: During the COVID-19 pandemic, Community Health Workers (CHWs) have been vital in helping to mitigate health disparities as they have helped serve as a bridge for communities and needed resources. In addition, they have been vital in improving health as they help build community capacity through their outreach, community education, and advocacy. Thus, the purpose of this project was to assess CHW’s perceptions of their participation in COVID-19 related projects implemented by the South Texas AHEC Program, throughout South Texas, and their alignment to Goodman et al.’s Dimensions of Community Capacity. Methods: Using qualitative description, five individual semi-structured interviews were conducted with CHWs in either English or Spanish based on the participant’s preference. The questions in the interview guide were created based on the Dimensions of Community Capacity and then qualitative content analysis was used to analyze the data. Data were then categorized based on their alignment with the Dimensions of Community Capacity. Results: In this project, CHW’s perceptions aligned well to the following Dimensions of Community Capacity: 1) Social and Interorganizational Networks, 2) Community Values, 3) Community History, 4) Community Power, 5) Leadership, 6) Resources, and 7) Sense of Community. Conclusions: These findings highlight the importance of capturing CHWs perceptions when working with CHWs on public health projects. Moreover, their perceptions of the COVID-19 projects implemented across South Texas provide examples of how their work aligned with seven dimensions that are essential to community capacity building

Estimating occupancy levels in enclosed spaces using environmental variables: A fitness gym and living room as evaluation scenarios

The understanding of occupancy patterns has been identified as a key contributor to achieve improvements in energy efficiency in buildings since occupancy information can benefit different systems, such as HVAC (Heating, Ventilation, and Air Conditioners), lighting, security, and emergency. This has meant that in the past decade, researchers have focused on improving the precision of occupancy estimation in enclosed spaces. Although several works have been done, one of the less addressed issues, regarding occupancy research, has been the availability of data for contrasting experimental results. Therefore, the main contributions of this work are: (1) the generation of two robust datasets gathered in enclosed spaces (a fitness gym and a living room) labeled with occupancy levels, and (2) the evaluation of three Machine Learning algorithms using different temporal resolutions. The results show that the prediction of 3-4 occupancy levels using the temperature, humidity, and pressure values provides an accuracy of at least 97%