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Search Results: 1 - 10 of 16839 matches for " Martha Garcia-Murillo "
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The Impact of Incentives in the Telecommunications Act of 1996 on Corporate Strategies
Martha Garcia-Murillo,Ian MacInnes
Computer Science , 2001,
Abstract: Rules are necessary to provide or shape the incentives of individuals and organizations. This is particularly true when free markets lead to undesirable outcomes. The Telecommunications Act of 1996 attempted to create incentives to foster competition. Ambiguity as well as the timing of the Act has led to delays in the clarification of rules and the rapid obsolescence of the document. The paper presents the strategies that common carriers adopted to try to tilt regulation in their favor, slow the entry of competitors, maintain their market leadership, and expand into other segments. Some of the strategies analyzed include lobbying efforts, court challenges, and lack of cooperation with new entrants.
Modelling and Control of Blowing-Venting Operations in Manned Submarines
Roberto Font,Javier Garcia,Jose Alberto Murillo,Francisco Periago
Mathematics , 2011,
Abstract: Motivated by the study of the potential use of blowing and venting operations of ballast tanks in manned submarines as a complementary or alternative control system for manoeuvring, we first propose a mathematical model for these operations. Then we consider the coupling of blowing and venting with the Feldman, variable mass, coefficient based hydrodynamic model for the equations of motion. The final complete model is composed of a system of twenty-four nonlinear ordinary differential equations. In a second part, we carry out a rigorous mathematical analysis of the model: existence of a solution is proved. As one of the possible applications of this model in naval engineering problems, we consider the problem of roll control in an emergency rising manoeuvre by using only blowing and venting. To this end, we formulate a suitable constrained, nonlinear, optimal control problem where controls are linked to the variable aperture of blowing and venting valves of each of the tanks. Existence of a solution for this problem is also proved. Finally, we address the numerical resolution of the control problem by using a descent algorithm. Numerical experiments seem to indicate that, indeed, an appropriate use of blowing and venting operations may help in the control of this emergency manoeuvre.
Abstract sectional category
F. Diaz,J. Calcines,P. Garcia,A. Murillo,J. Remedios
Mathematics , 2011,
Abstract: We study, in an abstract axiomatic setting, the notion of sectional category of a morphism. From this, we unify and generalize known results about this invariant in different settings as well as we deduce new applications.
Biomassa e atividades microbianas em solo sob pastagem com diferentes lota??es de ovinos
Garcia, Martha Regina Lucizano;Nahas, Ely;
Revista Brasileira de Ciência do Solo , 2007, DOI: 10.1590/S0100-06832007000200009
Abstract: the effect of grazing pressure in sheep production has been studied, but not in relation to soil microbiological parameters or the consequences on soil fertility. the effect of grazing pressure (gp) by sheep on biomass and microbial activity related to c and n compounds cycling in subtropical region soil was studied. soil samples were collected from the 0-10 cm and 10-20 cm layers in pastures with low gp (5 animals ha-1), high gp (40-50 animals ha-1) and in absence of animals, in a completely randomized design with 6 replicates. the highest values of microbial biomass and respiratory, nitrifying and enzymatic (urease and protease) activities were found in pasture soil with low gp. this pasture also accumulated highest amounts of organic matter and total n. these variables decreased in pastures without animals or with high gp. discontinuous vegetation and intense mineralization may have caused this reduction in the soils with pastures under high gp. it was observed a high correlation between organic matter, organic c and total n with the amounts of microbial biomass and enzymatic activity. the values of the variables under study were higher in the 0-10 cm than in the 10-20 cm layer.
Chemical Composition of Ground Pearl (Eurhizococcus colombianus) Cysts
Winston Qui?ones,Bernardo Vicente,Fernando Torres,Rosendo Archbold,Walter Murillo,Martha Londo?o,Fernando Echeverri
Molecules , 2008, DOI: 10.3390/molecules13010190
Abstract: Ground pearl (Eurhizococcus colombianus) is a crop pest in Colombia, withspecial impact on fig, grass, rubus and tomato plants. The insect is resistant to externalinsecticide application because it produces a thick waxy shell that isolates it from theenvironment. The composition of this shell was determined by NMR and MS as atriglyceride, whose fatty acid is transformed into other products with the metamorphosis ofthe insect. Additionally, several enzymatic inhibitors were assayed to control the insectwith negative results.
Cardiopatía isquémica en mujeres mexicanas
Solorio, Sergio;Hernández-González, Martha Alicia;Rangel Abundis, Alberto;Murillo-Ortiz, Blanca;
Archivos de cardiología de México , 2007,
Abstract: objective: to identify differences between both genders regarding coronary artery disease occurrence. patients and methods. in referred patients for cardiac catheterization we investigated coronary risk factors, clinical diagnosis, associated diseases, left ventricle ejection fraction, and coronary lesions. data were analyzed by x2 test, student t test, odds ratio and confidence intervals, a p value < 0.05 was considered significant. results: we studied 586 patients, 409 were men. women were older than men (59.43 ± 9.93 vs 56.80 ± 10.14 years old, p < 0.05). the frequency of coronary lesions in women was 56 vs 81% in men. the proportions of positive nuclear medicine studies (14 vs 16%) and exercise treadmill test (36 vs 28%) were similar. acute myocardial infarction was the most frequent diagnosis in men (46%) whereas in women it was angor pectoris (57%). smoking was observed more in men (72 vs 26%) and systemic arterial hypertension in women (65 vs 48%), there were no differences in diabetes mellitus and dyslipidemia frequencies. conclusion: systemic arterial hypertension was the risk factor more frequent in women, where as in men it was smoking. ischemia induction tests are less specific to identify coronary atherosclerosis in women. in spite of the clinical data, image and laboratory results, we had a great proportion of women without coronary lesions.
Paludismo grave en adultos mayores de 18 a os: 1 a o de experiencia Severe malarial infection in adults aged over 18 years: one-year experience
Luis Arencibia Pita,Martha Rosendo Jiménez,Aracelis Serrano Murillo,Reinaldo Menéndez Capote
Revista Cubana de Medicina Tropical , 2006,
Abstract: Se efectuó un estudio descriptivo transversal sobre las formas graves de paludismo que ingresaron en la Clínica Meditex durante el período enero-diciembre de 2004, las cuales constituyen la causa fundamental de ingreso en las unidades de cuidados intensivos de los países africanos. Se evaluó su comportamiento, órganos que mayormente afectaba y cómo puede ser esto influenciado por el grado de parasitemia. Se incluyeron los pacientes graves mayores de 18 a os, con una puntuación Apache II superior a 20 puntos. Al conocerse las formas graves de presentación más frecuentes y su relación con el grado de parasitemia, se evaluaron las complicaciones comunes y su mortalidad. Predominó la forma clínica cerebral (42,2 %) y se presentó con los grados más bajos de parasitemia al ingreso menor que 1 000 x mm3 (68,2 %) p< 0,005. Gran número de pacientes presentaron contracción de volumen como complicación, ocasionado por un déficit aporte hídrico, lo cual se evidencia con la mejoría clínica ante la corrección del medio interno. La mortalidad registrada resultó menor que las reportadas por otros autores. Se concluyó que la toma cerebral y hepática son las formas graves de presentación más frecuentes y su presencia no guarda relación con el grado de parasitemia al ingreso. The severe malarial forms are the main cause of admission to ICU in the majority of African countries, therefore, a cross-sectional descriptive trial was carried out in Meditex Clic in Luanda (January-December 2004) to evaluate the organs mostly affected and how the level of parasitemia influence them. Seriously-ill patients aged over 18 years, with Apache II score exceeding 20 points in Apache II score were included Once the most frequent severe forms of presentation and their association with the level of parasitemia were known, then common complications and mortality were evaluated. Clinical cerebral form (42.2%) prevailed, with the lowest parasitemia on admission, that is below 1000 x mm3 (68.2%), p< 0.005. A great deal of patients suffered reduced fluid volume as a complication resulting from fluid deficit, which clinically overcome after corrective actions based on fluid intake. The mortality rate observed in this study was lower than that reported by other trials. It was concluded that brain and hepatic effects are the most serious and frequent forms of presentation, with no association with the parasitemia level on admission.
Design of two molecular methodologies for the rapid identification of Colombian community-acquired methicillin-resistant Staphylococcus aureus isolates Dise o de dos metodologías moleculares para la rápida identificación de aislamientos de Staphylococcus aureus resistente a meticilina asociados a la comunidad en Colombia
Javier Antonio Escobar,Ingrid Tatiana Gómez,Martha Johanna Murillo,Betsy Esperanza Castro
Biomédica , 2011,
Abstract: Introduction. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates are increasing the frequency of infections in healthy persons in the community and hospitalized patients. In Colombia and the Andean region, CA-MRSA isolates have a genetic background that is related to the pandemic USA300 clone. Objective. To design and standardize two molecular methodologies for the rapid differentiation of Colombian community acquired and hospital acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) isolates. Materials and methods. Two molecular methodologies were standardized for the identification of CA-MRSA isolates. The first methodology is based in the differential digestion of the carbamate kinase (arcC) and guanylate kinase (gmk) genes in the sequences type 5 (ST5) and 8 (ST8), present in the HA-MRSA and CA-MRSA isolates respectively. The second methodology is based on the PCR amplification of the 5 specific virulence factors found in CA-MRSA and HA-MRSA isolates. The specificity and exactitude of each methodology were evaluated using 237 clinical MRSA isolates. Results. The first methodology identified 100% and 93.2% of the CA-MRSA and HA-MRSA isolates, respectively. The second methodology correctly identified the two isolates types (CA-MRSA and HA-MRSA). Conclusions. These two methodologies are a convenient alternative for the rapid identification of the CA-MRSA isolates in Colombia, compared with other techniques such as pulsed field gel electrophoresis and multilocus sequence typing, which take longer and are more expensive. Introducción. Los aislamientos Staphylococcus aureus resistentes a meticilina asociado a la comunidad (SARM-AC) están aumentando la frecuencia de infecciones en personas sanas de la comunidad y en pacientes hospitalizados. En Colombia y la región andina estos aislamientos tienen un componente genético relacionado con el clon pandémico USA300. Objetivo. Dise ar y estandarizar dos metodologías para la diferenciación rápida de aislamientos colombianos de Staphylococcus aureus resistente a meticilina asociado a la comunidad (SARM-AC) de los asociados al hospital (SARM-AH). Materiales y métodos. Se estandarizaron dos metodologías moleculares para la identificación de aislamientos de SARM-AC. La primera se basa en la digestión diferencial con tres enzimas de restricción de los genes carbamato quinasa (arcC) y guanilato quinasa (gmk) para los tipos de secuencia 5 (ST5) y 8 (ST8) correspondientes a aislamientos SARM-AH y SARM-AC, respectivamente. La segunda se basa en la amplificación por reacción en cadena
Control del cáncer cervicouterino en Colombia: la perspectiva de los actores del sistema de salud
Wiesner-Ceballos,Carolina; Moreno,Raúl Hernando Murillo; Pi?eros Petersen,Marion; Tovar-Murillo,Sandra Lourdes; Cendales Duarte,Ricardo; Gutiérrez,Martha Cielo;
Revista Panamericana de Salud Pública , 2009, DOI: 10.1590/S1020-49892009000100001
Abstract: objectives: to characterize the health system stakeholder's perspective on the basics of the political, economic, and sanitary context, as well as the ways in which control activities are being realized in four of colombia's health departments. methods: this was a qualitative study of four colombian health departments chosen for their differing cervical cancer mortality rates and their planned disease control efforts (boyacá, caldas, magdalena, and tolima). semistructured interviews were conducted of health care managers, insurance coordinators, and public and private health institutions at the departmental and municipals levels. focus groups comprised of professionals from health insurance companies and health care services providers were convened. data analysis was based on the grounded theory with open codes related to the roles of health care managers, insurance companies, and heath care services provided. the technical reports were compared to the testimonies of interviewees. results: thirty-eight interviews and 14 focus groups (70.9% response rate) were conducted and 12 technical reports reviewed. cervical cancer is not perceived to be a public health priority. interest centers on the flow of financial resources within the health system. findings indicated unsatisfactory communication among the stakeholders and no consensus on the subject. planning is limited to meeting the status quo. staffing is inadequate. cases with positive outcomes are lost to follow-up due to the fragmentation that results from affiliation with different health care systems. conclusions: the financial situation, normative planning, and the challenges of decentralization affect the skill-building, at-risk coverage, and the control activities needed for effective screening programs. what is needed is an integrated, more efficiently organized program in which all the health system stakeholders participate.
Impact of different grazing systems for bovine cattle on the soil microbiological and chemical characteristics
Garcia, Martha Regina Lucizano;Sampaio, Alexandre Amstalden Moraes;Nahas, Ely;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000700024
Abstract: the objective of this work was to study the effect of grazing systems: rotational, continuous and the absence of cattle, in pastures of brachiaria brizantha on microbial activity (respiratory, potential nitrification, solubilizing, and enzymatic) and on the chemical attributes (contents of organic carbon, total nitrogen, organic phosphorus, and moisture) of eutrustox soil over one year. eight canchim breed animals were used. the samples were collected in the four seasons from 2005 to 2006. the average of organic c, organic p, and moisture contents, as well as potential nitrification and solubilizing activity and urease and acid phosphatase activities were significantly higher in the spring and/or summer than in autumn and/or winter. the total nitrogen amounts did not vary among seasons. while the respiratory activity was larger during winter and summer, cellulase activity was smaller during spring than in the other seasons. except for organic p, higher values of the variables studied were observed in the rotational grazing. the results indicate that the hot and rainy season and the rotational grazing system cause increases in the soil microbiological and chemical attributes.
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