An advection-diffusion model to explain thermal surface anomalies off Cape Trafalgar

The authors describe an almost permanent thermal anomaly, with low surface-temperature values, off Cape Trafalgar. The existence of strong tidal currents in the alongshore direction, and the local offshore orientation of isobaths at this point, support the hypothesis of vertical forcing by interaction between the barotropic tide and topography. This is simplified for modelisation as the pass of a tidal current over a ridge, which is considered uniform in the crossshore direction. A bidimensional model in finite differences is developed to reproduce the main features observed experimentally. The combined effects of advection (both vertical and horizontal) and diffusion appear to be very important. The model is sensitive to the assumed values of thermal diffusion coefficients and their depth dependence, as well as to heat flux through the sea surface. To have realistic values for these parameters, a unidimensional diffusion model aimed at reproducing the mixed layer and thermocline observed in this area during summer has been developed. Heat flux and diffusion coefficients are adjustment parameters of the model, and, once determined, they are introduced in the 2-D advection-diffusion model. Results from simulation seem to be in good agreement with CTD observations, confirming our initial hypothesis.Se describe una anomalía térmica caracterizada por bajas temperaturas superficiales frente al cabo de Trafalgar. Debido a que la orientación de las isóbatas en esta área es casi perpendicular a la costa y a que existen fuertes corrientes de marea a lo largo de ella, se desarrolla la hipótesis de que la interacción entre las corrientes de marea y la topografía son los mecanismos responsables de esta anomalía. Para revisar esta hipótesis se desarrolla en el presente trabajo un modelo de advección-difusión que estudia el efecto del paso de una corriente de marea sobre un obstáculo. El modelo es sensible a ciertos parámetros, como los coeficientes de difusión térmica y el flujo de calor en la superficie del mar. Por ello desarrollamos un modelo monodimensional que reproduce la formación de la capa de mezcla y la termoclina estacional usando estos parámetros como parámetros de ajuste. Una vez encontrados los valores adecuados, son introducidos en el modelo de advección-difusión. Los resultados obtenidos parecen estar de acuerdo con los datos experimentales.Instituto Español de Oceanografí

Viabilidad económica, social y ambiental del Hyperloop, el tren del futuro

En este documento se analiza la viabilidad económica, social y ambiental de la implementación del Hyperloop (medio de transporte capaz de alcanzar altas velocidades debido a su innovador funcionamiento con aire presurizado en el interior de un tubo), poniendo foco en una hipotética ruta entre las ciudades de Barcelona y Mataró. Este medio de transporte se encuentra en desarrollo actualmente; está siendo diseñado por varias empresas y se están llevando a cabo numerosas pruebas, no obstante, por el momento no se han obtenido los resultados deseados, por lo que nada es definitivo. Primeramente, una vez establecidos los objetivos y alcance de este trabajo, se ha explicado el funcionamiento del Hyperloop, detallando las principales partes que lo forman. Una vez descrito el ámbito más funcional y técnico, se ha procedido a analizar minuciosamente la ruta de estudio, siendo esta como se ha indicado la que une las ciudades de Barcelona a Mataró, estudiando la historia, longitud, elevación, y trayecto, entre otras características. Por otra parte, se ha hecho un estudio de la viabilidad económica de esta ruta de Hyperloop, detallando principalmente la inversión inicial necesaria para su infraestructura y el resultado del ejercicio financiero, tomando como referencia los datos proporcionados en Hyperloop Alpha. También se ha analizado el impacto ambiental que supondría esta implantación, teniendo en cuenta tanto la energía producida como la generada en esta hipotética ruta, llevando a cabo una comparación con los medios de transporte existentes. Por último, se ha elaborado un análisis social y de igualdad de género, focalizándose en el impacto generado en los diferentes medios de transporte tras la inserción del Hyperloop, y el posible efecto inmobiliario generado, cuyo resultado depende principalmente de la localización de la estación. Con todo, se ha concluido que la ruta entre Barcelona y Mataró es viable, sin embargo, se estima que rutas con distancias más largas ofrecerán mejores resultados, principalmente en el sector económico, donde habrá un mayor margen y un tiempo menor para la recuperación de la inversión inicialEn aquest document s'analitza la viabilitat econòmica, social i ambiental de la implementació del Hyperloop (mitjà de transport capaç d'assolir altes velocitats a causa del seu innovador funcionament amb aire pressuritzat a l'interior d'un tub), posant focus en una ruta hipotètica entre les ciutats de Barcelona i Mataró. Aquest mitjà de transport es troba en desenvolupament actualment; està sent dissenyat per diverses empreses i s'estan duent a terme nombroses proves, però de moment no s'han obtingut els resultats desitjats, per la qual cosa res no és definitiu. Primerament, un cop establerts els objectius i l'abast d'aquest treball, s'ha explicat el funcionament de l'Hyperloop, detallant les parts principals que el formen. Un cop descrit l'àmbit més funcional i tècnic, s'ha analitzat minuciosament la ruta d'estudi, essent aquesta com s'ha indicat la que uneix les ciutats de Barcelona a Mataró, estudiant la història, longitud, elevació i trajecte, entre d'altres característiques. D'altra banda, s'ha fet un estudi de la viabilitat econòmica d'aquesta ruta d'Hyperloop, detallant principalment la inversió inicial necessària per a la infraestructura i el resultat de l'exercici financer, prenent com a referència les dades proporcionades a Hyperloop Alpha. També s‟ha analitzat l‟impacte ambiental que suposaria aquesta implantació, tenint en compte tant l‟energia produïda com la generada en aquesta hipotètica ruta, duent a terme una comparació amb els mitjans de transport existents. Finalment, s'ha elaborat una anàlisi social i d'igualtat de gènere, focalitzant-se en l'impacte generat als diferents mitjans de transport després de la inserció de l'Hyperloop, i el possible efecte immobiliari generat, el resultat del qual depèn principalment de la localització de l'estació. Amb tot, s'ha conclòs que la ruta entre Barcelona i Mataró és viable, però, s'estima que rutes amb distàncies més llargues oferiran millors resultats, principalment al sector econòmic, on hi haurà un marge més gran i un temps menor per a la recuperació de la inversió inicialThis document analyzes the economic, social and environmental viability of the implementation of the Hyperloop (a means of transport capable of reaching high speeds due to its innovative operation with pressurized air inside a tube), focusing on a hypothetical route between the cities of Barcelona and Mataró. This means of transport is currently under development; it is being designed by several companies and numerous tests are being carried out, however, for the moment the desired results have not been obtained, so nothing is definitive. Firstly, once the objectives and scope of this work have been established, a functional explanation of the Hyperloop has been carried out, detailing the main parts that make it up. Once the most functional and technical area has been described, the study route has been carefully analyzed, being this, as indicated, the one that connects the cities of Barcelona to Mataró, studying the history, length, elevation, and route, among others. characteristics. On the other hand, a study of the economic viability of this Hyperloop route has been carried out, mainly detailing the initial investment required for its infrastructure and the result of the financial year, taking as reference the data provided in Hyperloop Alpha. The environmental impact that this implementation has also been analyzed, taking into account both the energy produced and that generated on this hypothetical route, carrying out a comparison with existing means of transport. Finally, a social and gender equality analysis has been executed, focusing on the impact generated in the different means of transport after the insertion of the Hyperloop, and the possible real estate effect generated, the result of which depends mainly on the location of the station. All in all, it has been concluded that the route between Barcelona and Mataró is viable, however, it is estimated that routes with longer distances will offer better results, mainly in the economic sector, where there will be a greater margin and a shorter time for the recovery of the initial investmen

Hydrographic conditions of the Ibiza Channel during November 1990, March 1991 and July 1992

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Circulation of water masses through the Ibiza Channel

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Tomosynthesis in pulmonary cystic fibrosis with comparison to radiography and computed tomography: a pictorial review

The purpose of this pictorial review is to illustrate chest imaging findings of cystic fibrosis (CF) using tomosynthesis (digital tomography), in comparison to radiography and computed tomography (CT). CF is a chronic systemic disease where imaging has long been used for monitoring chest status. CT exposes the patient to a substantially higher radiation dose than radiography, rendering it unsuitable for the often needed repeated examinations of these patients. Tomosynthesis has recently appeared as an interesting low dose alternative to CT, with an effective dose of approximately 0.08 mSv for children and 0.12 mSv for adults. Tomosynthesis is performed on the same X-ray system as radiography, adding only about 1 min to the normal examination time. Typical pulmonary changes in CF such as mucus plugging, bronchial wall thickening, and bronchiectases are shown in significantly better detail with tomosynthesis than with traditional radiography. In addition, the cost for a tomosynthesis examination is low compared to CT. To reduce the radiation burden of patients with CF it is important to consider low dose alternatives to CT, especially in the paediatric population. Tomosynthesis has a lower radiation dose than CT and gives a superior visualisation of pulmonary CF changes compared to radiography. It is important to further determine the role of tomosynthesis for monitoring disease progression in CF

Clinical features of infantile hepatic hemangioendothelioma

PurposeInfantile hepatic hemangioendothelioma (IHHE) is the most common type of hepatic vascular tumor in infancy. We conducted this study to review our clinical experience of patients with IHHE and to suggest management strategies.MethodsWe retrospectively analyzed the medical records of 23 IHHE patients (10 males, 13 females) treated at the Asan Medical Center between 1996 and 2009.ResultsMedian age at diagnosis was 38 days (range, 1 to 381 days). Seven patients (30%) were diagnosed with IHHE based on sonographically detected fetal liver masses, 5 (22%) were diagnosed incidentally in the absence of symptoms, 5 (22%) had congestive heart failure, 3 (13%) had skin hemangiomas, 2 (9%) had abnormal liver function tests, and 1 (4%) had hepatomegaly. All diagnoses were based on imaging results, and were confirmed in three patients by histopathology analysis. Six patients were observed without receiving any treatment, whereas 12 received corticosteroids and/or interferon-alpha. One patient with congestive heart failure and a resectable unilobar tumor underwent surgical resection. Three patients with congestive heart failure and unresectable tumors were managed by hepatic artery embolization with/without medical treatment. At a median follow-up of 29 months (range, 1 to 156 months), 21 (91%) patients showed complete tumor disappearance or >50% decrease in tumor size. One patient died due to tumor-related causes.ConclusionIHHE generally has a benign clinical course with low morbidity and mortality rates. Clinical course and treatment outcome did not differ significantly between medically treated and non-treated groups. Surgically unresectable patients with significant symptoms may be treated medically or with hepatic artery embolization