1,158 research outputs found
Learning from hydrological and hydrogeological problems in civil engineering. Study of reservoirs in Andalusia, Spain
This study presents a novel review of seven case histories of Andalusian reservoirs (Southern Spain) affected by different hydrological and hydrogeological problems that have led to severe malfunctions. The failures reported are related to (i) water quality degradation due to salinization and acid mine drainage, (ii) leakage in karstified terrains, (iii) environmental and hydrogeological impacts associated with an inadequate water planning and (iv) large evaporative losses from the reservoir. Detailed information on the geological context, hydrological/hydrogeological origin of the problem, repercussions on infrastructure functioning and remedial measures applied or proposed has been gathered for each case. Results of on-site research carried out by the authors in some of the locations studied and a comparative analysis of similar case histories at international level are also included. The purpose of this work is to emphasize the need of learning from past mistakes and provide guidance for future dam construction works, especially in the Mediterranean region. It also highlights the role of geological and hydrogeological research in dam sitting and the consequences of inadequate terrain characterisation, biased hydrological planning and data misinterpretation or undervaluation. This review evidences the need of conducting comprehensive studies that do not only focus on the infrastructure itself, but also on non-constructive aspects (monitoring of geological features and hydrological variables) and relevant processes (e.g. leakage, salinization and contamination) that might compromise the efficient functioning of the infrastructur
Beach Leveling Using a Remotely Piloted Aircraft System (RPAS): Problems and Solutions
The size and great dynamism of coastal systems require faster and more automated mapping methods like the use of a remotely piloted aircraft system (RPAS) or unmanned aerial vehicle (UAV). This method allows for shorter intervals between surveys. The main problem for surveying using low-altitude digital photogrammetry in beach areas is their visual homogeneity. Obviously, the fewer the homologous points defined by the program, the lower the accuracy. Moreover, some factors influence the error performed in photogrammetric techniques, such as flight height, flight time, percentage of frame overlap (side and forward), and the number of ground control points (GCPs). A total of 72 different cases were conducted varying these factors, and the results were analyzed. Among the conclusions, it should be highlighted that the error for noon flights is almost double that for the early morning flights. Secondly, there is no appreciable difference regarding the side overlap. But, on the other side, RMSE increased to three times (from 0.05 to 0.15 m) when forward overlap decreased from 85% to 70%. Moreover, relative accuracy is 0.05% of the flying height which means a significant increase in error (66%) between flights performed at 60 and 100 m height). Furthermore, the median of the error for noon flights (0.12 m) is almost double that for the early morning flights (0.07 m) because of the higher percentage of grids with data for early flights. Therefore, beach levelings must never be performed at noon when carried out by RPAS. Eventually, a new parameter has been considered: the relationship between the number of GCPs and the surface to be monitored. A minimum value of 7 GCP/Ha should be taken into account when designing a beach leveling campaign using RPAS.Fundacion Campus Tecnologico de Algeciras; Coastal Engineering Research group (University of Cadiz
Case report: Challenges and implications of conduction system pacing in pediatrics: Case series
Cardiac electrical stimulation in children usually is needed in the setting of complete congenital atrioventricular block, atrioventricular block after heart surgery, and bradycardia associated with some specific channelopathies. In cases of atrioventricular block, the high percentage of ventricular stimulation raises concern on the deleterious effects of chronic stimulation of the right ventricle. In recent years, physiologic stimulation has developed as a valid approach for adult patients and a great interest has risen in offering conduction system pacing also to the pediatric population. We present three pediatric cases of stimulation of the conduction system (His bundle or left bundle branch), in order to show the intrinsic particularities and challenges implied in these new techniques
Soluciones Creativas de Intervención (LUGH)
En este texto se puede encontrar información sobre los antecedentes del proyecto LUGH ITESO Soluciones creativas de intervención, así como los objetivos del trabajo que incluyen la vinculación entre empresas socialmente responsables con escenarios, comunidades, organizaciones u otros esfuerzos de la sociedad por mejorar su entorno. De este modo la empresa obtiene un beneficio en términos de posicionamiento, a la vez que produce un beneficio social tangible. Durante el período primavera 2016, se desarrollaron estrategias y piezas de comunicación para las organizaciones Plenitud de vida, Concertando México, Juntos por los demás y Capeltic. En este informe se incluye también la descripción del método de trabajo que el proyecto propone para la realización de estrategias de comunicación e intervención social
Simulación avanzada en la docencia práctica de la signatura Pediatría
Depto. de Salud Pública y Materno - InfantilFac. de MedicinaFALSEsubmitte
2013. Documento Sevilla de Consenso sobre Alternativas a la Transfusión de Sangre Alogénica. Actualización del Documento Sevilla
La transfusión de sangre alogénica (TSA) no es inocua, y como consecuencia han surgido múltiples alternativas a la misma (ATSA). Existe variabilidad respecto a las indicaciones y buen uso de las ATSA. Dependiendo de la especialidad de los médicos que tratan a los pacientes, el grado de anemia, la política transfusional, la disponibilidad de las ATSA y el criterio personal, estas se usan de forma variable. Puesto que las ATSA tampoco son inocuas y pueden no cumplir criterios de coste-efectividad, la variabilidad en su uso es inaceptable. Las sociedades españolas de Anestesiología y Reanimación (SEDAR), Hematología y Hemoterapia (SEHH), Farmacia Hospitalaria (SEFH), Medicina Intensiva y Unidades Coronarias (SEMICYUC), Trombosis y Hemostasia (SETH) y Transfusiones Sanguíneas (SETS) han elaborado un documento de consenso para el buen uso de la ATSA. Un panel de expertos de las 6 sociedades ha llevado a cabo una revisión sistemática de la literatura médica y elaborado el 2013. Documento Sevilla de Consenso sobre Alternativas a la Transfusión de Sangre Alogénica. Solo se contempla las ATSA dirigidas a disminuir la transfusión de concentrado de hematíes. Se definen las ATSA como toda medida farmacológica y no farmacológica encaminada a disminuir la transfusión de concentrado de hematíes, preservando siempre la seguridad del paciente. La cuestión principal que se plantea en cada ítem se formula, en forma positiva o negativa, como: «La ATSA en cuestión reduce/no reduce la tasa transfusional». Para formular el grado de recomendación se ha usado la metodología Grades of Recommendation Assessment, Development and Evaluation (GRADE)
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
Type II Supernova Spectral Diversity. I. Observations, Sample Characterization, and Spectral Line Evolution
We present 888 visual-wavelength spectra of 122 nearby type II supernovae (SNe II) obtained between 1986 and 2009, and ranging between 3 and 363 days post-explosion. In this first paper, we outline our observations and data reduction techniques, together with a characterization based on the spectral diversity of SNe II. A statistical analysis of the spectral matching technique is discussed as an alternative to nondetection constraints for estimating SN explosion epochs. The time evolution of spectral lines is presented and analyzed in terms of how this differs for SNe of different photometric, spectral, and environmental properties: velocities, pseudo-equivalent widths, decline rates, magnitudes, time durations, and environment metallicity. Our sample displays a large range in ejecta expansion velocities, from ∼9600 to ∼1500 km s-1 at 50 days post-explosion with a median Hα value of 7300 km s-1. This is most likely explained through differing explosion energies. Significant diversity is also observed in the absolute strength of spectral lines, characterized through their pseudo-equivalent widths. This implies significant diversity in both temperature evolution (linked to progenitor radius) and progenitor metallicity between different SNe II. Around 60% of our sample shows an extra absorption component on the blue side of the Hα P-Cygni profile ("Cachito" feature) between 7 and 120 days since explosion. Studying the nature of Cachito, we conclude that these features at early times (before ∼35 days) are associated with Si ii λ6355, while past the middle of the plateau phase they are related to high velocity (HV) features of hydrogen lines.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
Educar para los nuevos Medios. Claves para el desarrollo de la competencia mediática en el entorno digital
Educar es una de las labores más complejas, intensas y, a la vez, más maravillosas que puede acometer una persona. Ser docente es una tarea ilusionante. En un mundo en el que la información es cada vez más importante por la rapidez con que se produce y consume, la variedad de recursos con que se difunde constituye un reto en el papel de los educadores y educadoras. La educación para la comunicación, a través de los nuevos medios, requiere de habilidades y estrategias específicas e implica prácticas innovadoras. Este texto ofrece claves para desarrollar la competencia mediática necesaria para entender, usar y comunicar en el entorno digital. Desde el concepto de competencia mediática y la escuela prosumidora se muestran experiencias y planteamientos en distintos niveles educativos y contextos curriculares que ofrecen pistas para educar a la ciudadanía. Esta alfabetización aúna la perspectiva de la experiencia de docente receptor y consumidor, atendiendo a la recepción crítica de la información, la selección y administración de la misma, el reconocimiento de valores e ideologías y la gestión emocional, junto a la elaboración y creación de contenidos
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