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Search Results: 1 - 10 of 221659 matches for " Sergio; Pérez Utrilla "
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Nefroureterectomía laparoscópica: nueva posición para el manejo ureteral
Aguilera Bazán,Alfredo; Alonso y Gregorio,Sergio; Pérez Utrilla,Manuel; Cansino Alcaide,Ramón; Cisneros Ledo,Jesús; Pe?a,Javier de la;
Archivos Espa?oles de Urología (Ed. impresa) , 2007, DOI: 10.4321/S0004-06142007000600009
Abstract: objectives: the main challenge of laparoscopic nephroureterectomy is the management of distal ureter, which also will have an important repercussion in the oncological outcome of many cases. we present our experience in such aspect, considering that we performed the last five laparoscopic nephroureterectomies in forced trendelemburg position, resulting in a more comfortable and safe management of the distal ureter. methods: between august and december 2006 we performed five purely laparoscopic nephroureterectomies with bladder cuff positioning the patient in forced trendelemburg, a position similar to that of laparoscopic radical cystectomy or prostatectomy. results: mean surgical time was 182 minutes (170-210). mean blood loss was 100 cc and no patient required transfusion. mean hospital stay was four days. conclusions: we believe this position is a good alternative for the management of the distal ureter during the laparoscopic approach. the technique is very similar to open surgery, which continues being the gold standard today.
Prostatectomía radical laparoscópica versus robótica
Cáceres,Felipe; Sánchez,Carlos; Martínez-Pi?eiro,Luis; Tabernero,Angel; Alonso,Sergio; Cisneros,Jesús; Cabrera Castillo,Pedro Manuel; álvarez Maestro,Mario; Martín Hernández,Mario; Pérez-Utrilla Pérez,Manolo; Pe?a,Jesús J. de la;
Archivos Espa?oles de Urología (Ed. impresa) , 2007, DOI: 10.4321/S0004-06142007000400013
Abstract: objectives: laparoscopic surgery has demonstrated that it is a good alternative to conventional surgery for the treatment of localized prostate cancer. robotic surgery could be a therapeutic option. we try to evaluate both techniques, analyzing a series of parameters that allow us to describe the advantages and disadvantages of both techniques. methods: we performed a medline search and reviewed the main series of laparoscopic radical prostatectomy (lrp) and robotic radical prostatectomy (rrp). the parameters analyzed for each techniques were: oncological results, functional results, blood loss, transfusion rates, surgical times, complications rates, learning curve and cost. results: both techniques have the advantage of being minimally invasive, which results in better recovery and aesthetic results. the learning curve of the robotic prostatectomy is shorter, 10 to 20 cases in comparison with 50 to 60 for the lrp. cost analysis is more favourable for lrp, with a single-use instrument expenditure of 533 dollars per patient in comparison with 1.705 dollars with the robot. the cost of the robot is 1.200.000 dollars plus 100.000 dollars of annual maintenance (1). operative time was 182 minutes [141-250] for robotic surgery and 234 min. [151-453] for lrp. within the same institution, like montsouris, times are very similar: 155 min. for the rrp and 181 min. for the (lrp). mean operative blood loss was 234 ml [75-500] for the robot and 482 ml [185-859] for the lrp, depending on the technique employed and the institution. complication rate is similar for both techniques. the percentage of positive surgical margins is 20.6% for lrp and 19.24% for rrp. long term results on the biochemical psa recurrence cannot be given due to the short life of both techniques. continence rates are 56-100% for lrp and 70-98% for rrp. potency rates are 25-82% for lrp and 79-100% for rrp. it is difficult to evaluate hospital stay because it depends on the politics of the medical institutions;
Methodology and Equations of Mineral Production Forecast
—Part I. Crude Oil in the UK and Gold in Nevada, USA. Prediction of Late Stages of Production

Sergio Pérez Rodríguez
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.35040

The equations of mineral production forecast link the change in time of mineral reserves with the production and the ratio of reserves to production. These equations allow us to model the development of the mineral resources evaluated at any scale. Probabilistic bidimensional charts made from montecarlo simulations provide intervals of confidence for the forecasts. The set of equations is devised and presented for a variety of applications to the oil and gas industry, as well to the production of any other mineral resource, either metals or non metals, whose ore deposit volumes and production might be quantified. The cases studied in the UK and USA are at late stages of production, periods for what the equations are most suitable to be applied without further adjustments. Experimental design allows the diagnosis of the likely values of the variables pertaining to the equations, in order to achieve the results provided by conventional production forecasts or to explore other scenarios of investigation. The method can be practical to evaluate commitments of production of mineral resources with time, to support strategic plans for companies, corporations, countries or regions based on those evaluations, for the screening and ranking of mineral assets based on their production potential and many other tasks where the prediction of future volumes of mineral production is required.

Methodology and Equations of Mineral Production Forecast. Part II. The Fundamental Equation. Crude Oil Production in USA  [PDF]
Sergio Pérez Rodríguez
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.36044

The fundamental equation of mineral production allows to model and design the dynamics of mineral production, however complex they are or could be. It considers not only the case of a constant production to reserves ratio for given intervals of time, but with a piecewise approach, it is also enabled to account the variation on time of this ratio. With a constant production to reserves ratio, the limit expression of the fundamental equation takes the form of an Erlang distribution with a fixed shape parameter. The rate parameter equals the scale factor. The discrete piecewise version, instead of considering the reserves and the production to reserves ratio being constant through certain intervals of time, updates both variables by units of time. This version, using either lineal or non lineal functions for the variables involved, let to model known production profiles or to forecast them by experimental design. The Hubbert’s linearization updated with recent data and the p-box method applied to determine ultimate recovery of U.S. crude oil reserves indicate official accounts underestimate them. The analysis of the ideal model of production based on Hubbert’s linearization and curve, can be made by decomposing it in the distribution with time of the reserves and of the production to reserves ratio. The distribution of reserves with time is synchronized for both the ideal Hubbert’s curve and real profiles, disregarding whether they match or not. The departure of real profiles from the ideal Hubbert’s curve lies on the differences or correspondences of the distribution with time of the production to reserves ratio. The MonteCarlo simulation applied to forecast US crude oil production for the next five years points to a slow decline, with average annual yields presenting a difference lower than 10% between the start and the end of the simulation.

Identidad, diferencia y contradicción en la Lógica de Hegel
Sergio Pérez Cortez
Signos filosóficos , 2006,
Abstract: Resumen: Dentro de todo sistema filosófico existen algunas categoría que resultan fundamentales para la comprensión del conjunto. Este es el caso de las categorías de identidad, diferencia y contradicción para la filosofía de Georg W. F. Hegel. Contenidas en el libro II de la Lógica, tales categorías se sitúan en lo que quizá es el corazón del proyecto hegeliano: establecer una relación crítica con la filosofía trascendental que conduzca a una metafísica poskantiana, manifiesta sobre todo en la unidad del sujeto pensante y del objeto pensado. Por ello, el artículo está estructurado en tres grandes secciones: 1) la relación que Hegel establece con la Crítica de la Razón Pura, 2) un análisis de las categorías de identidad, diferencia y contradicción tal como aparecen en las dos versiones de la Lógica y 3) una serie de conclusiones que surgen de la reivindicación de la categoría de contradicción, sin duda la más controvertida entre las nociones de la filosofía del Concepto. Abstract: Within all philosophical systems there are some categories that are fundamental to the understanding of the whole. This is the case of categories such as identity, difference and contradiction in Hegel’s philosophy. In the second book of the Logik, such categories are set in what appears to be the heart of the hegelian project: to establish a critical relation with transcendental philosophy that leads to a postkantian metaphysics, evident above all in the unity of the thinking subject and the thought object. That is why, this paper is structured into three main sections: 1), the relation that Hegel establishes with the Critique of Pure Reason, 2) an analysis of the categories of identity, difference and contradiction as they appear in the two versions of the Logik and, 3) some conclusions that arise from the vindication of the category of contradiction, without a doubt, the most controversial among the notions of the philosophy of the concept.
El huerto maya yucateco en el siglo XVI
Sergio Moctezuma Pérez
Estudios de cultura maya , 2011,
Sergio Moctezuma Pérez
Ciencia y Sociedad , 2010,
Abstract: El presente artículo tiene por objetivo mostrar cuáles son las principales aportaciones que la antropología puede hacer al estudio de los sistemas agrícolas tradicionales - particularmente al sistema de huertos familiares. Se presenta una revisión de los componentes básicos en las definiciones de huertos para demostrar que su complejidad inherente limita el foco de análisis de las investigaciones. Posteriormente se plantea la manera en que la antropología se acerca al estudio de los huertos mediante técnicas y metodologías dise adas para obtener información socioeconómica y cultural de las familias que lo poseen. Por último se revisa lo que se ha encontrado sobre los huertos de San Francisco Tepeyanco, Tlaxcala que fue el sitio de estudio en los a os 1970 y 1980 de antropólogos y biólogos interesados en conocer la relación entre el hombre y su ambiente, y específicamente entre las familias campesinas y sus huertos.
Nefroureterectomía abierta y laparoscópica en tumores uroteliales del tracto urinario superior: experiencia inicial
Aguilera,Alfredo; Pérez-Utrilla,Manuel; Girón,Manuel; Cansino,Ramón; Gil,Ana; Pe?a,Javier de la;
Actas Urológicas Espa?olas , 2009, DOI: 10.4321/S0210-48062009001000008
Abstract: purpose: advances in urological laparoscopy have increased the oncological safety of this approach for managing upper urinary tract tumours, although the open surgical route remains the method of choice. we present our experience with the laparoscopic approach over the past four years and compare it to open surgery. materials and methods: between 1995 and 2009 a total of 95 nephroureterectomies were carried out for tumours: 70 by open surgery and 25 by laparoscopy. lumbotomy with endoscopic detachment of the ureter was the most common approach in open surgery, while transperitoneal access was used for laparoscopy in all cases, with laparoscopic bladder cuff resection in most patients (56%). results: mean procedure time for the open nephroureterectomies was 205 (130-300) min, with a mean blood loss of 525 (100-1,800) ml and 17 (24.2%) transfusions. the mean hospital stay was 8.4 (3-30) days. mean procedure time for the laparoscopic nephroureterectomies was 189 (120-270) min, with a mean blood loss of 130 (100-400) ml and 4 (16%) transfusions. the mean hospital stay was 4.5 (2-28) days. conclusions: the patients who underwent the laparoscopic procedure had a lower transfusion rate and shorter hospital stay. oncological control was similar for both approaches, although a longer follow-up and a larger series of cases are still needed for the laparoscopic approach.
Los mitos sobre el suicidio. La importancia de conocerlos
Pérez Barrero,Sergio A;
Revista Colombiana de Psiquiatría , 2005,
Abstract: suicide myths are wrong criteria that disrupt the task of suicide prevention. for this reason the diffusion of these myths by the media is necessary in order to take measures to prevent this cause of death.
Los mitos sobre el suicidio. La importancia de conocerlos Suicide Myths. The Importance of their Knowledge
Sergio A Pérez Barrero
Revista Colombiana de Psiquiatría , 2005,
Abstract: Los mitos sobre el suicidio son criterios equivocados que entorpecen la prevención de dicha conducta, por lo que se hace necesario difundirlos para que sean erradicados y se faciliten las acciones preventivas. Suicide myths are wrong criteria that disrupt the task of suicide prevention. For this reason the diffusion of these myths by the media is necessary in order to take measures to prevent this cause of death.
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