Literature review: a surgeon’s view of recurrent hiatal hernia

Las hernias hiatales recidivantes constituyen una patología común que generan un reto diagnóstico y terapéutico para cirujanos y gastroenterólogos. Generalmente se presentan de forma asintomática o con síntomas atípicos y se asocian a factores fisiológicos, propios del paciente y de la técnica quirúrgica. Su tratamiento es complejo y dependiendo de la causa de los síntomas pueden requerir manejo médico o quirúrgico. En este artículo, se pretenden definir pautas para la identificación y manejo de esta patología, así como establecer claves para el tratamiento desde un enfoque quirúrgico.Recurrent hiatal hernias are a common pathology that generate a diagnostic and therapeutic challenge for surgeons and gastroenterologists. They are generally asymptomatic or present with atypical symptoms and are associated with the patient’s own physiological factors and the surgical technique. Treatment is complex and, depending on the cause of the symptoms, will require either medical or surgical management. This article starts from a surgical approach to define guidelines for identification and management of this condition and to establish keys to treatment

Classification and prioritization of usability problems using an augmented classification scheme

Various methods exist for conducting usability evaluation studies in health care. But although the methodology is clear, no usability evaluation method provides a framework by which the usability reporting activities are fully standardized. Despite the frequent use of forms to report the usability problems and their context-information, this reporting is often hindered by information losses. This is due to the fact that evaluators’ problem descriptions are based on individual judgments of what they find salient about a usability problem at a certain moment in time. Moreover, usability problems are typically classified in terms of their type, number, and severity. These classes are usually devised by the evaluator for the purpose at hand and the used problem types often are not mutually exclusive, complete and distinct. Also the impact of usability problems on the task outcome is usually not taken into account. Consequently, problem descriptions are often vague and even when combined with their classification in type or severity leave room for multiple interpretations when discussed with system designers afterwards. Correct interpretation of these problem descriptions is then highly dependent upon the extent to which the evaluators can retrieve relevant details from memory. To remedy this situation a framework is needed guiding usability evaluators in high quality reporting and unique classification of usability problems. Such a framework should allow the disclosure of the underlying essence of problem causes, the severity rating and the classification of the impact of usability problems on the task outcome. The User Action Framework (UAF) is an existing validated classification framework that allows the unique classification of usability problems, but it does not include a severity rating nor does it contain an assessment of the potential impact of usability flaws on the final task outcomes. We therefore augmented the UAF with a severity rating based on Nielsen’s classification and added a classification for expressing the potential impact of usability problems on final task outcomes. Such an augmented scheme will provide the necessary information to system developers to understand the essence of usability problems, to prioritize problems and to tackle them in a system redesign. To investigate the feasibility of such an augmented scheme, it was applied to the results of usability studies of a computerized physician order entry system (CPOE). The evaluators classified the majority of the usability problems identically by use of the augmented UAF. In addition it helped in differentiating problems that looked similar but yet affect the user–system interaction and the task results differently and vice versa. This work is of value not only for system developers but also for researchers who want to study the results of other usability evaluation studies, because this scheme makes the results of usability studies comparable and easily retrievable

Aplicación para la inspección espacial, volumétrica y seccional interactiva de la Catedral de Santiago de Compostela

[ES] El presente artículo describe el proceso de diseño, producción e implementación de una aplicación destinada a permitir el análisis formal interactivo de la Catedral de Santiago de Compostela. La complejidad geométrica del modelo edificio para el detalle requerido, derivada principalmente de la profusión de elementos estilísticospresentes en el mismo y que constituye al fin y al cabo una de sus señas características, impuso utilizar soluciones basadas en cálculo de radiosidad por refinamiento progresivo para la generación de un modelo que pudiese ser manipulable en tiempo real, con calidad visual de iluminación global, a la vez que seccionable interactivamente mediante interacción multitáctil.[EN] This paper describes the design, production and implementation of an application for the formal analysis of the Cathedral of Santiago de Compostela. The geometrical complexity of the model of this building for the level of detail required, derived from the profusion of stylistic elements present, that constitutes one of its signs of identity leaded to use the progressive refinement radiosity method to generate a model which could be handled in real-time, adding the visual quality of globalillumination, to be implemented in an application that allows the user to interactively inspect and cross-section the model.Barneche Naya, V.; Hernández Ibáñez, LA.; Jaspe Villanueva, A.; Fariña Fernández, G. (2012). Aplicación para la inspección espacial, volumétrica y seccional interactiva de la Catedral de Santiago de Compostela. Virtual Archaeology Review. 3(6):78-82. https://doi.org/10.4995/var.2012.4448OJS788236CONANT, KENNETH, J. (1983): "Arquitectura románica da Catedral de Santiago de Compostela" Ed. Colexio Oficial de Arquitectos de Galicia. Vigo.FRANCO TABOADA, J.A, y TARRIO CARRODEGUAS, S. (1999): "As Catedrais de Galicia. Descrición Gráfica". Departamento de Representación e Teoría Arquitectónicas. Ed. Xunta de Galicia. Santiago de Compostela.ILUX (2010): "Catedral, Libro de Piedra" Ilux Visual Technologies. [on-line] [Consulta 15-04-2011] http://www.ilux.es/es/catedralMARTIN, S. & EINARSSON, P. (2010): "Real Time Radiosity Architecture" Presentación en el curso "Advances in Real-Time Rendering" en SIGGRAPH 2010 [online] [Consulta 15-04-2011]http://publications.dice.se/attachments/Siggraph10-ARR-RealtimeRadiosityArchitecture.pptMARTZ. P. et al. (2007): "OpenSceneGraph Reference Manual v2.2", Ed. Kuehne. B. and Marktz. P [online] [Consulta 15-04-2011] http://www.osgbooks.com/books/osg_refman22.htmlTAÍN GUZMÁN, M. (1999): "Trazas, Planos y Proyectos del Archivo de la Catedral de Santiago", Ed. Diputación Provincial de A Coruña

CHC+RT: coherent hierarchical culling for ray tracing

We propose a new technique for in-core and out-of-core GPU ray tracing using a generalization of hierarchical occlusion culling in the style of the CHC++ method. Our method exploits the rasterization pipeline and hardware occlusion queries in order to create coherent batches of work for localized shader-based ray tracing kernels. By combining hierarchies in both ray space and object space, the method is able to share intermediate traversal results among multiple rays. We exploit temporal coherence among similar ray sets between frames and also within the given frame. A suitable management of the current visibility state makes it possible to benefit from occlusion culling for less coherent ray types like diffuse reflections. Since large scenes are still a challenge for modern GPU ray tracers, our method is most useful for scenes with medium to high complexity, especially since our method inherently supports ray tracing highly complex scenes that do not fit in GPU memory. For in-core scenes our method is comparable to CUDA ray tracing and performs up to 5.94× better than pure shader-based ray tracing

Comparative performance of three propeller blades used for push pumps.

With the increasing trend to use pumps in aquaculture operations, tests were conducted on push pumps with three different propeller types. Type 21, a stainless two-bladed propeller where the blades were aligned together to form the Letter “I”, was found capable of delivering 10 m3/min at zero head. It was also the most efficient. The Type 2S propeller which has two blades made of brass with the blades forming the letter “S”, was found to have the lowest efficiency and also gave the lowest discharge. The performance of Type 3 propeller which has three blades made of brass is intermediate between the two other types. Push pumps are effective alternative pumping system for aquaculture

Physically Walking in Digital Spaces - a Virtual Reality Installation for Exploration of Historical Heritage

Immersive Virtual Reality Systems have been extensively used during recent years for the exploration of architectonic spaces. This paper describes how the use of transitable immersive virtual reality systems, that is, those that allow the user to physically walk while exploring the virtual world, can greatly empower the experience of perception of space in architecture. The text describes a particular example of one installation of this kind that was developed by the authors and how it was implemented for the interactive experience of the virtual reconstruction of a housing unit on a pre-roman settlement. This installation is open to the public as part of a permanent exhibition and constitutes the final output of the research at this time