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Search Results: 1 - 10 of 430694 matches for " ángel M. Bravo-Santos "
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Dynamic Cognitive Self-Organized TDMA for Medium Access Control in Real-Time Vehicle to Vehicle Communications
Mario Manzano,Felipe Espinosa,ángel M. Bravo-Santos,Enrique Santiso
Mathematical Problems in Engineering , 2013, DOI: 10.1155/2013/574528
Abstract:
Direct Polarization for q-ary Source and Channel Coding
ángel Bravo-Santos
Mathematics , 2015,
Abstract: The basic polar transformation introduced by Arikan for binary codes also polarizes over finite fields of prime order and more general transformations polarize over finite fields. Direct coding of q-ary sources and channels is a process that can be implemented with simple and efficient algorithms. However, direct polar decoding of q-ary sources and channels is a difficult task. In this paper we introduce a likelihood ratio (LR) vector that can be expressed recursively for decoding q-ary polar codes defined via the basic polar transformation for finite fields of prime order, or via an extended polar transformation for finite fields. With the recursive LR the successive cancellation (SC) decoding is applied in a straightforward way. The complexity is quadratic in the order of the field, but the use of the LR vector introduces factors that soften that complexity. The Bhattacharyya parameters are expressed as a function of the LR vectors, as in the binary case, facilitating the construction of the codes. We have applied direct polar coding to sources and channels with alphabets and signal constellations of various sizes, from 5 to 1024, and different codeword lengths. Our results suggest that direct q-ary polar coding could be used in real scenarios.
Communications with decode-and-forward relays in mesh networks
Angel Bravo-Santos,Petar M. Djuric
Mathematics , 2012,
Abstract: We consider mesh networks composed of groups of relaying nodes which operate in decode-and-forward mode, where each node from a group relays information to all the nodes in the next group. We study these networks in two setups, one where the nodes have complete channel state information from the nodes that transmit to them, and another when they only have the statistics of the channel. We derive recursive expressions for the probabilities of errors of the nodes and present several implementations of detectors used in these networks. We compare the mesh networks with multihop networks, the latter being formed by a set of parallel sections of multiple relaying nodes. We demonstrate with numerous simulations that there are significant improvements in performance of mesh over multihop networks in various scenarios.
Comparación de la Eficacia Analgésica de Codeína más paracetamol vs Tramadol en el Tratamiento del Dolor por Cáncer Comparison of the analgesic effectiveness of codeine plus paracetamol vs Tramadol in the Treatment of Cáncer Pain
R. F. Rodríguez,Luís E. Bravo,A. M. ángel,M. F. Rodríguez
Revista de la Sociedad Espa?ola del Dolor , 2008,
Abstract: El dolor es el síntoma más importante en 70% de pacientes que padecen cáncer avanzado. La terapia con analgésicos utilizada en forma adecuada, controla el dolor en 80-90% de los pacientes. Objetivos. Comparar la eficacia analgésica y seguridad de la codeína más acetaminofén (CA) y Clorhidrato de Tramadol (T) en el alivio del dolor por cáncer. Método. Se realizó un ensayo clínico controlado doble ciego, en pacientes con dolor por cáncer de intensidad moderada o severa. En forma aleatoria se asignó un grupo de pacientes para ser tratados con la combinación de Codeína más paracetamol, mientras que el otro grupo recibió Clorhidrato de Tramadol por un periodo de tres semanas. La intensidad del dolor fue medida con una escala numérica de cero a diez, considerándose como dolor de intensidad moderada el marcado en la escala entre 5-7 y de intensidad severa de 8-10. El tratamiento analgésico se consideró eficaz cuando el dolor desapareció o disminuyó a una intensidad leve, comprendida entre 1-4. Resultados. Se incluyeron 115 pacientes: 59 recibieron CA y 56 recibieron T. En el grupo de pacientes que recibió CA 58% aliviaron con una dosis inicial de codeína de 150 mg/día y 8% con la dosis doblada; 34% no aliviaron. En el grupo de pacientes tratado con T el dolor alivió en 62% de los pacientes con la dosis inicial de 200mg/día y 11% con la dosis doblada, mientras que 27% no experimentó alivio. Las diferencias entre los dos grupos no fueron significativas en cuanto a su eficacia analgésica. El grupo que recibió Tramadol presentó en forma significativa, mayor incidencia de efectos colaterales de intensidad leve: náusea (p: 0.05, RR: 0.62; IC95%: 0.38-1.01), mareo (p: 0.04; RR: 0.58; IC95%: 0.33-1.01) y pérdida de apetito (p: 0.001; RR: 0.08; IC95%: 0.01-0.59). Conclusión. No existen diferencias en cuanto a la eficacia analgésica de CA y T en el tratamiento del dolor por cáncer. Con el uso de T se presentó una mayor incidencia de efectos colaterales de intensidad leve. Pain is the principal symptom in 70% of patients with severe cáncer. Analgesics therapy with a proper management controls pain in 80-90% of patients. Objective. Compare the analgesic efficacy and tolerability of codeine plus acetaminophen (CA) and tramadol clorhydrate (T) in the relief of cáncer pain. Method. A double blind, randomize controlled clinical trial was perform in patients with modérate to severe pain intensity. Randomly patients were assigned in a group for receiving codeine plus acetaminophen and in other group for receiving tramadol chlorhydrate for a three weeks period. Pain intensity was
Análisis de la esperanza de vida libre de discapacidad a lo largo de la biografía: de la madurez a la vejez
Escobar Bravo,Miguel ángel; Puga González,M.a Dolores; Martín Baranera,Monserrat;
Gaceta Sanitaria , 2012, DOI: 10.1016/j.gaceta.2011.12.016
Abstract: objective: to determine the life stages in which disability-free life expectancy is shortened before the age of 70 years. method: a retrospective longitudinal analysis was carried out in a cohort of 1,286 non-institutionalized people aged from 70 to 74 years old living in metropolitan areas. disability was measured by instrumental and basic activities of daily living. disability-free life expectancy was calculated. the kaplan-meier method was used to calculate survival probabilities. results: the incidence of basic disability increased from 50 to 54 years old and progressively accelerated until the age of 65-69 years old when the probability of instrumental disability was slightly higher among men than among women (0.23 in men versus 0.19 in women). disability-free survival was lower among women than among men both for all types of disability (logrank = 5.80; p = 0.016) and for basic disability (logrank = 4.315; p = 0.038). conclusions: this study reveals the importance of instrumental disability for domestic tasks among older men. women had a lower probability of disability-free survival and were more likely to be affected by any type of disability as well as by basic disability. for both genders, there is a slight decrease in disability-free survival from the age of 40 to 60 years. from this age onwards, this decrease markedly accelerates.
Gliptodontes (Xenarthra, Glyptodontidae) del Pleistoceno Tardío (Rancholabreano) de Hidalgo, Centro de México
Bravo-Cuevas, Víctor M.;Ortiz-Caballero, Elizabeth;Cabral-Perdomo, Miguel ángel;
Boletín de la Sociedad Geológica Mexicana , 2009,
Abstract: an important sample of glyptodontidae remains was recovered from the south-central region of the state of hidalgo. the fossil material was recovered from aftuviolacustrine unnamed sedimentary sequence that consists of poorly to moderate consolidated clays, silts, and gravels; the specimens are associated with remains of bison (bison), which indicates a rancholabrean land mammal age. the sample includes two carapace fragments and 10 isolate osteoderms. the osteoderms are typical hexagonal with two to five pilose follicles, the central figure is polygonal, concave and slightly raised; there are eight to nine peripheral figures, smaller in size, roughly trapezoidal in shape, and symmetrically arranged around the center. all of these features are comparable to the rosette pattern of glyptotherium floridanum. thus the specimens from hidalgo are assigned to this species. in mexico, the genus glyptotherium is known from sonora, chihuahua, aguascalientes, jalisco, estado de mexico, and veracruz. the presence of this taxon in hidalgo is formally reported and is added to previously known record of north american glyptodonts, extending its distribution range to what is now part of central mexico.
Parasitosis intestinales en ni os ingresados en el Hospital Universitario Pediátrico del Cerro, La Habana, Cuba
Fidel A. Nú?ez,Odalys M. González,. José R. Bravo,ángel A. Escobedo
Revista Cubana de Medicina Tropical , 2003,
Abstract: Se realizó un estudio sobre parasitismo intestinal en 401 ni os ingresados en el Hospital Universitario Pediátrico del Cerro entre los meses de mayo y junio de 1999. Para esta finalidad se tomó una muestra representativa, aleatoria y estratificada por servicios. Por cada ni o, se recogieron 3 muestras de heces preservadas en formaldehído, las que se procesaron por 3 métodos parasitológicos. La prevalencia de parasitismo intestinal fue de 15 % en el hospital, y no se encontraron diferencias entre el estrato de ni os ingresados en Gastroenterología con el resto de los servicios en cuanto a comensales y parásitos en general (p> 0,05); sin embargo, prevalecieron los comensales en el segundo grupo (p< 0,01). Los coccidios intestinales, Cryptosporidium parvum y Cyclospora cayetanensis predominaron en los servicios de Gastroenterología, sobre el resto de los servicios (p< 0,01). El grupo de edad mayor de 4 a os (escolares) fue el más afectado, tanto por protozoos como por comensales (p< 0,01), excepto Cryptosporidium parvum que afectó más a los lactantes (p< 0,05). El análisis de algunos antecedentes epidemiológicos demostró que aquellos ni os que comían frutas con cáscaras sin lavar, los que ingerían vegetales sin lavar, y los que andaban descalzos, estaban más propensos a la infección (RR> 1). Además se demostró una mayor frecuencia de infección por parásitos intestinales, entre los que vivían en zona rural, tomaban agua de pozos o ríos, y defecaban en letrinas o a cielo abierto (RR> 1). Estos resultados sugirieron que a pesar del conocimiento existente sobre los factores epidemiológicos y de riesgo, las parasitosis intestinales continúan incidiendo en las poblaciones infantiles. A study on intestinal parasitism was conducted among 401 children admitted in the Pediatric Teaching Hospital of Cerro, from May to June, 1999. To this end, a representative, randomized and stratified sample by service was taken. 3 samples of feces per child were collected, preserved in formaldehyde, and processed by 3 parasitological methods.There was an intestinal parasitism prevalence of l5 % at the hospital and there were no differences between the stratum of children admitted in Gastroenterology and the rest of the services as regards commensals and parasites in general (p> 0.05); however, commensals predominated in the second group (p< 0.01) The intestinal coccidia, Cryptosporidium parvum and Cyclospora cayetanensis prevailed in the Gastroenterology service over the rest of the services (p< 0.01). The age group over 4 (school children) was the most affected, both by protozoa a
Comparación de la Eficacia Analgésica de Codeína más paracetamol vs Tramadol en el Tratamiento del Dolor por Cáncer
Rodríguez,R. F.; Bravo,Luís E.; ángel,A. M.; Rodríguez,M. F.; León,M. E.;
Revista de la Sociedad Espa?ola del Dolor , 2008,
Abstract: pain is the principal symptom in 70% of patients with severe cáncer. analgesics therapy with a proper management controls pain in 80-90% of patients. objective. compare the analgesic efficacy and tolerability of codeine plus acetaminophen (ca) and tramadol clorhydrate (t) in the relief of cáncer pain. method. a double blind, randomize controlled clinical trial was perform in patients with modérate to severe pain intensity. randomly patients were assigned in a group for receiving codeine plus acetaminophen and in other group for receiving tramadol chlorhydrate for a three weeks period. pain intensity was measure using a numeric scale from zero to ten in which modérate pain goes from 5-7, and severe pain goes from 8-10. analgesic treatment was considered to be effective when pain disappear or become mild, 1-4 in the numeric scale. results. one hundred fifteen patients participated, 59 receive ca and 56 t. in the group of patients that receive ca, 58% achieved pain relief with the initial dose of 150 mg/d and 8% responded to the double dose; 34% didn't experience pain relief. in the group patients treated with t pain relief occurred in 62% of patients with the initial dose of 200mg/d and 11% with the double dose; 27% didn't experienced pain relief. differences between both groups were not significant in the analgesic efficacy. the tramadol group experienced in a significant way a higher incidence of adverse events of mild intensity: nausea (p: 0.05, rr: 0.62; ic95%: 0.38-1.01), dizziness (p: 0.04; rr: 0.58; ic95%: 0.33-1.01) and lost of appetite (p: 0.001; rr: 0.08; ic95%: 0.01-0.59). conclusion. efficacy of c and t during a treatment of 23 days was similar, no statistical differences were found. there were no differences in the analgesic effectiveness between ca and t in the management of cáncer pain. with the use of t a higher incidence of adverse events of mild intensity were reported.
ARQUEOLOGíA APLICADA AL DESARROLLO DE COMUNIDADES ATACAME?AS
Bravo González,ángel;
Chungará (Arica) , 2003, DOI: 10.4067/S0717-73562003000200008
Abstract: i have been working in the native communities of coyo and quitor, since the year 1996, it is located in the community of san pedro de atacama, province of el loa in northern chile (second region). i have worked here in order to value, protect and manage two important archaeological sites called: the tulor village and the quitor fortress, which belong to this worthy cultural patrimony. both projects have been financed by conadi in calama, and the projects have been sponsored by the communities themselves. the main idea of these projects is based on the intrinsically capacity the communities have to manage their own patrimony. for this, they have been trained in management and financial subjects and expert guides in the sites have been also prepared. the performance of both projects has had some obstacles,which are discussed here.
El SaaS y el Cloud-Computing: una opción innovadora para tiempos de crisis
ángel Hernández Bravo
Revista Espa?ola de Innovación, Calidad e Ingeniería del Software , 2009,
Abstract:
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