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Search Results: 1 - 10 of 240604 matches for " Sergio Pérez Rodríguez "
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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
 [PDF]

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

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
Abstract:

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.

Orbital entanglement production in Andreev billiards with time-reversal symmetry
Sergio Rodríguez-Pérez,Marcel Novaes
Physics , 2013,
Abstract: We study orbital entanglement production in a chaotic cavity connected to four single-channel normal-metal leads and one superconducting lead, assuming the presence of time-reversal symmetry (TRS). The scattered state of two incident electrons is written as the superposition of several two-outgoing quasi-particle states, four of which are orbitally entangled in a left-right bipartition. We calculate numerically the mean value of the squared norm of each scattered state's component, as functions of the number of channels in the superconducting lead. Its behavior is explained as resulting from the proximity effect. We also study statistically the amount of entanglement carried by each pair of outgoing quasi-particles. When the influence of the superconductor is more intense, the average entanglement is found to be considerably larger than that obtained using normal cavities.
Multi-Sensor Person Following in Low-Visibility Scenarios
Jorge Sales,Raúl Marín,Enric Cervera,Sergio Rodríguez,Javier Pérez
Sensors , 2010, DOI: 10.3390/s101210953
Abstract: Person following with mobile robots has traditionally been an important research topic. It has been solved, in most cases, by the use of machine vision or laser rangefinders. In some special circumstances, such as a smoky environment, the use of optical sensors is not a good solution. This paper proposes and compares alternative sensors and methods to perform a person following in low visibility conditions, such as smoky environments in firefighting scenarios. The use of laser rangefinder and sonar sensors is proposed in combination with a vision system that can determine the amount of smoke in the environment. The smoke detection algorithm provides the robot with the ability to use a different combination of sensors to perform robot navigation and person following depending on the visibility in the environment.
Caracterización de la morbilidad materna extremadamente grave
álvarez Toste,Mireya; Salvador álvarez,Sergio; González Rodríguez,Guillermo; Pérez,Disnardo Raúl;
Revista Cubana de Higiene y Epidemiolog?-a , 2010,
Abstract: introduction: at the present time there is an increasing interest in carrying out of critically severe mother morbidity analysis because it is an indicator closely associated with the mother death and a valid alternative to use as assessment measure of maternal cares. objective: to characterize the critically severe mother morbidity in ciudad de la habana from january to june, 2009. methods: a cross-sectional study was conducted in all pregnant diagnosed with critically severe mother morbidity in maternal hospitals and in the gynecology and obstetrics services of general and clinical and surgical hospitals, according to inclusion criteria. information was obtained from the medical record of each pregnant over its prenatal and hospital care. results: diagnosis was made in 46 pregnant with a mean age of 28 years. in 89.1% mother risks were identified where the more frequent ones were high blood pressure, asthma, diabetes mellitus and urinary sepsis. conclusions: critically severe mother morbidity was more frequent after labor. according the inclusion criteria the more prevalent causes were those related to the management of the patient (surgery, icu, transfusion) and specific disease, septic and hypovolemic shock.
Caracterización de la morbilidad materna extremadamente grave Characterization of critically severe mother morbidity
Mireya álvarez Toste,Sergio Salvador álvarez,Guillermo González Rodríguez,Disnardo Raúl Pérez
Revista Cubana de Higiene y Epidemiología , 2010,
Abstract: INTRODUCCIóN: En la actualidad existe un interés creciente por realizar el análisis de la morbilidad materna extremadamente grave, pues resulta ser un indicador muy asociado con la muerte materna y una alternativa válida para utilizarse como medida de evaluación de los cuidados maternos. OBJETIVO: Caracterizar la morbilidad materna extremadamente grave en la Ciudad de La Habana, desde enero hasta junio del a o 2009. MéTODOS: Se realizó un estudio transversal cuyo universo de estudio lo constituyeron todas las gestantes que se diagnosticaron como morbilidad materna extremadamente grave en los hospitales maternos y servicios ginecoobstétricos de hospitales generales y clinicoquirúrgicos, según criterios de inclusión. La información se obtuvo mediante la historia clínica de cada gestante durante su atención prenatal y hospitalaria. RESULTADOS: Se diagnosticaron 46 gestantes, con una edad promedio de 28 a os. Se identificaron riesgos maternos en el 89,1 % de las gestantes. Los riesgos de mayor frecuencia fueron la hipertensión arterial, el asma, la diabetes mellitus y la sepsis urinaria. CONCLUSIONES: La morbilidad materna extremadamente grave ocurrió con mayor frecuencia después del parto. Según los criterios de inclusión, las causas de mayor ocurrencia fueron las relacionadas con el manejo instaurado al paciente (cirugía, UCI, transfusión) y la enfermedad específica (shock séptico e hipovolémico). INTRODUCTION: At the present time there is an increasing interest in carrying out of critically severe mother morbidity analysis because it is an indicator closely associated with the mother death and a valid alternative to use as assessment measure of maternal cares. OBJECTIVE: To characterize the critically severe mother morbidity in Ciudad de La Habana from January to June, 2009. METHODS: A cross-sectional study was conducted in all pregnant diagnosed with critically severe mother morbidity in maternal hospitals and in the Gynecology and Obstetrics services of general and clinical and surgical hospitals, according to inclusion criteria. Information was obtained from the medical record of each pregnant over its prenatal and hospital care. RESULTS: Diagnosis was made in 46 pregnant with a mean age of 28 years. In 89.1% mother risks were identified where the more frequent ones were high blood pressure, asthma, diabetes mellitus and urinary sepsis. CONCLUSIONS: Critically severe mother morbidity was more frequent after labor. According the inclusion criteria the more prevalent causes were those related to the management of the patient (surgery, ICU, transfusion)
Adenoflemón cervical en la tercera edad. Presentación de un caso Cervical adenophlegmon in old age. A case report
Fidel Castro Pérez,Raúl Rodríguez González,Sergio Vento Cruz,Milagros Ramos Cruz
Revista de Ciencias M??dicas de Pinar del R?-o , 2011,
Abstract: Se presenta el caso de una paciente de 70 a os de edad, raza negra, del sexo femenino, con antecedentes de padecer de diabetes mellitus e hipertensión arterial. Se valoró en la consulta externa del Policlínico Universitario Ernesto Guevara de la Serna de Sandino, de Pinar del Río. Fue evaluado en conjunto por un grupo de especialistas, al presentar un cuadro caracterizado por el aumento de volumen superficial de la región lateral izquierda del cuello, por debajo de la rama horizontal de la mandíbula, a nivel del músculo esternocleidomastoideo, cerca y debajo del pabellón auricular y la parótida, de aproximadamente 5 cm. de diámetro, móvil, doloroso, de superficie lisa y consistencia renitente, sin cambios en la coloración de la piel. Al examen físico otorrinolaringológico no se encontraron otras alteraciones. Se le hizo un ultrasonido en la región afectada y valoró en conjunto el caso efectuado el tratamiento médico, al establecerse el diagnóstico clínico e imaginológico de adenoflemón cervical. Se procedió además a la realización de una BAAF. Los autores presentan las experiencias derivadas de la atención del caso, no frecuente a esta edad y revisan la literatura médica sobre el tema, con especial referencia al diagnóstico y tratamiento. A 70 year-old, black race, female patient, suffering from diabetes mellitus and hypertension attended to the consultation. The case was analyzed at "Ernesto Guevara de la Serna" outpatient clinic in Sandino, Pinar del Rio. A group of specialists assessed the case that presented a chart characterized by an increase of superficial volume in left lateral region of the neck, below the horizontal branch of the mandible to the level of sternocleidomastoid muscle, near and below outer ear and the parotid, around 5cm of diameter, movable, painful of smooth surface and renitent consistency, without changes in skin color. No other alterations were found at physical examination or ENT specialist examination while imaging studies in the affected region were as well conducted, the case was assessed considering all these procedures to order medical treatment, clinical and imaging diagnosis established a cervical adenophlegmon. A fine needle aspiration biopsy was also performed. The authors presented the experience derived from the medical care of the case, which is not frequent in this age and reviewed the medical literature about the topic, with special emphasis on diagnosis and treatment.
Dise?o de un medio de ense?anza, para el estudio de técnicas hemostáticas en sangramientos postonsilectomía
Vento Cruz,Sergio J; Ramos Cruz,Milagros; Clemente Rodríguez,María E; Pérez Pérez,Medardo;
Revista de Ciencias M??dicas de Pinar del R?-o , 2007,
Abstract: three otolaryngologists designed a teaching aid at "pepe portilla" provincial children teaching hospital in pinar del rio in 2006. it was shown by means of this model the different anatomical structures of the oro-pharynx and the behavior to be followed in presence of a bleeding in patients underwent a tonsillectomy. disposal and low cost materials were used for the design . a promotion of 100 percent was attained in students from the brigade 88 knowing the oropharyngeal anatomy as well as the techniques for the hemostasis in presence of bleeding in patients undergone a tonsillectomy.
Dise o de un medio de ense anza, para el estudio de técnicas hemostáticas en sangramientos postonsilectomía Design of a Teaching Aid in the Study of the Hemostatic Techniques in Post-tonsillectomy Bleeding
Sergio J Vento Cruz,Milagros Ramos Cruz,María E Clemente Rodríguez,Medardo Pérez Pérez
Revista de Ciencias M??dicas de Pinar del R?-o , 2007,
Abstract: Se confeccionó un medio de ense anza por tres especialistas de Otorrinolaringología del Hospital Pediátrico Provincial Docente "Pepe Portilla" de Pinar del Río en el a o 2006. Se lograron mostrar, mediante el uso de esta maqueta, las diferentes estructuras anatómicas de la orofaringe y la conducta a seguir ante el sangramiento en pacientes amigdalectomizados. Se utilizaron materiales desechables y de bajo costo para su dise o. Se obtuvo el 100 % de promoción en los estudiantes de la brigada # 88 con el aprendizaje de la anatomía orofaríngea y el dominio de las técnicas para hacer hemostasia en el sangramiento de pacientes tonsilectomizados. Three otolaryngologists designed a teaching aid at "Pepe Portilla" Provincial Children Teaching Hospital in Pinar del Rio in 2006. It was shown by means of this model the different anatomical structures of the oro-pharynx and the behavior to be followed in presence of a bleeding in patients underwent a tonsillectomy. Disposal and low cost materials were used for the design . A promotion of 100 percent was attained in students from the Brigade 88 knowing the oropharyngeal anatomy as well as the techniques for the hemostasis in presence of bleeding in patients undergone a tonsillectomy.
Virulence Markers in Staphylococcus aureus Strains Isolated from Hemodialysis Catheters of Mexican Patients  [PDF]
Gloria Paniagua-Contreras, Teresita Sáinz-Espu?es, Eric Monroy-Pérez, José Raymundo Rodríguez-Moctezuma, Diego Arenas-Aranda, Erasmo Negrete-Abascal, Sergio Vaca
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.24061
Abstract: Methicillin-resistant Staphylococcus aureus is an increasingly important cause of nosocomial bacterial infections worldwide. S. aureus is responsible for several pathologies, including skin infections, endocarditis, meningitis, deep-tissue ulcers, and sepsis. S. aureus biofilm formation on catheters and other medical devices is a major post-operative concern, because biofilms are often the source of persistent and difficult to treat bacterial infections. While catheter-related S. aureus infections have been reported, the strains responsible for these infections have not been genetically characterized. We genetically characterized S. aureus strains isolated from hemodialysis catheters in Mexican patients. The frequency of 35 genes coding for adhesins, toxins, and other virulence-associated products in the 55 isolated S. aureus strains was determined using PCR, while real-time PCR was used to examine the level of gene expression. Of the 55 S. aureus strains isolated from 109 patients, 45 (81.8%) were determined to be methicillin-resistant. The icaA, rbf, sarA, and agr genes are involved in biofilm formation and bacterial dispersion and were detected in 96.3%, 40.0%, 74.5%, and 100% of S. aureus strains, respectively, and 70.9% of the strains formed a detectable biofilm. Interestingly, 67.2% of the strains contained the icaA, agr, spa, clfA, sdrC, sdrD, sdrE, seg, seh, and sei genes, suggesting that this gene combination is important for successful catheter colonization. The results of this study provide significant insight into the virulence gene make-up of catheter-colonizing S. aureus strains, and will assist in developing a more targeted treatment approach for persistent S. aureus biofilm contamination of medical devices.
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