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Search Results: 1 - 10 of 6015 matches for " Ortiz- Ibarra "
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Un testimonio de modernización en la ganadería o en la agricultura?
J. Trinidad Chavéz Ortiz,Eduardo Ibarra Thennet
Nueva antropología , 1987,
Abstract:
Numerical Study of Highly Nonlinear Photonic Crystal Fiber with Tunable Zero Dispersion Wavelengths  [PDF]
Alejandro Barrientos García, Igor A. Sukhoivanov, José Amparo Andrade Lucio, Oscar Gerardo Ibarra Manzano, Igor Guryev, Juan Carlos Hernández García, Gabriel Ramos Ortiz
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2015, DOI: 10.4236/jemaa.2015.75016
Abstract: Solid-core silica photonic crystal fiber is proposed borrowing the concept of golden ratio (1.618) and keeping it between pitch and air hole diameter Λ/d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ = 1 μm), we need air-holes diameters d = 0.618 μm in order to achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm; this gives us the possibility to use the fiber for supercontinuum generation, by pumping close to that points, pulse compression or reshaping. We analyzed a series of fibers using this relation and showed the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm, with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method with perfectly matched layers, including the material dispersion directly into the model applying the Sellmeier’s equation.
Lesiones cutáneas no cicatrizales como único dato clínico del síndrome de varicela congénita: reporte de un caso
Reyna-Figueroa, Jesús;Ortiz-Ibarra, Federico Javier;Pérez-Antonio, Beatriz;
Boletín médico del Hospital Infantil de México , 2006,
Abstract: introduction. varicella infections cases in pregnant women may have a more severe clinical course, and there is also the risk of vertical transmission of the viral infection, with the subsequent development of congenital or neonatal varicella. cases of congenital varicella syndrome (cvs) were first described in 1947, since then, a little more than 60 cases of cvs have been reported. the cvs consists of a spectrum of anomalies including scaring with derma to mal distribution, ocular abnormalities and limb deformities. case report. an unusual case of cvs with dermatologic involvement, but without other injuries at birth is described. the mother contracted chicken pox at 10 weeks' gestation. we didn't find any previous report of newborns with cvs in mexico. conclusion. the particular condition of this case is the presence of non cicatricial injuries as only clinical data, supported by a positive serology against varicella-zoster virus.
Validación de la escala NOSEP-1 para el diagnóstico de sepsis nosocomial en recién nacidos prematuros menores de 1 500 g
Reyna-Figueroa, Jesús;Brise?o-Vázquez, Rafael;Ortiz-Ibarra, Federico Javier;
Boletín médico del Hospital Infantil de México , 2005,
Abstract: introduction. nosep-1 score was developed by mahieu et al, to predict nosocomial sepsis in neonatal intensive care unit patients based on 3 laboratory, 1 clinical, and 1 historical variables potentially related with nosocomial infections. material and methods. nosep-1 score had 5 items including: c reactive protein, neutrophil fraction, thrombocytopenia, fever and parenteral nutrition. we evaluated the nosep score in premature patients lower than 1 500 g to predict nosocomial sepsis in the neonatal intensive care unit of instituto nacional de perinatologia. validity was evaluated using receiver operating characteristic curve (roc), sensitivity, specificity, positive predictive value and negative predictive value. gold standard was the blood culture and 2 or more features of systemic inflammatory response syndrome.we analyzed 2 groups of patients. group 1:50 new-borns with negative blood culture, and group 2: 52 with positive blood culture, respectively. results.the point score was 8, with sensitivity of 62.7%, specificity of 70%, positive predictive value of 53.8%, and negative predictive value of 50%. conclusions. nosep-1 score is a simple indicator for detecting nosocomial infections in premature patients; however in the present study analyzing infants < 1 500 g, the sensitivity, specificity, positive predictive value, negative predictive value were lower than original report. we propose that if some of the variables are modified, the specificity may be improved.
Design of 2nd order low-pass active filters by preserving the physical meaning of design variables
F. Sandoval-Ibarra,M. Cuesta-Claros,R. Moreno-Espinosa,E. Ortiz-Levy
Revista mexicana de física E , 2011,
Abstract: The purpose of this paper is, by one hand, offer to students basics on active filter design by introducing the Butterworth approach as well as some practical examples not only to show the proposed design flow (DF), but also to show that the design flow's stages have physical meaning mainly supported on physical laws. With the help of these laws, further, it is shown how additional filter design specifications can be translated to the physical design without affect neither the design approach nor DF. On the other hand, because any physical implementation suffer of the non-idealities of electronic components, the modeling of some of them based on both experimental results and spice simulations is presented in order to show how unwanted effects may be added to the DF. An advantage of this proposal is that DF preserves the physical meaning of the design variables. The laboratory-based learning adopted in this work has allowed to students be able to understand physical concepts, capture and analyze experimental data, and use design tools in a correct way mainly to avoid "trial and error" approaches. El propósito de este artículo es, por un lado, ofrecer a los estudiantes fundamentos del dise o de filtros activos usando la aproximación Butterworth y presentando ejemplos prácticos no solo para mostrar el flujo de dise o propuesto, sino también para mostrar que las etapas del dise o tiene un significado físico que esta soportado en leyes físicas. Con ayuda de esas leyes se muestra como otras especificaciones de dise o del filtro pueden ser incorporadas en el dise o físico sin afectar la aproximación de dise o ni el flujo mismo de dise o. Por otro lado, porque toda implementación física es afectada por las no idealidades de los componentes electrónicos, se presenta el modelado de varios de ellos soportado en datos de simulación spice y resultados experimentales a manera de mostrar como esa información se incorpora al flujo de dise o. Una ventaja de esta propuesta es que se conserva el significado físico de toda variable de dise o. El aprendizaje basado en el trabajo de laboratorio, que es la técnica adoptada en este trabajo, ha permitido a los estudiantes comprender conceptos físicos, capturar y analizar información experimental, y usar herramientas de dise o de manera correcta para evitar aproximaciones tipo "prueba y error".
Design of 2nd order low-pass active filters by preserving the physical meaning of design variables
F. Sandoval-Ibarra,M. Cuesta-Claros,R. Moreno-Espinosa,E. Ortiz-Levy
Revista mexicana de física , 2011,
Abstract: El propósito de este artículo es, por un lado, ofrecer a los estudiantes fundamentos del dise o de filtros activos usando la aproximación Butterworth y presentando ejemplos prácticos no sólo para mostrar el flujo de dise o propuesto, sino también para mostrar que las etapas del dise o tiene un significado físico que está soportado en leyes físicas. Con ayuda de esas leyes se muestra cómo otras especificaciones de dise o del filtro pueden ser incorporadas en el dise o físico sin afectar la aproximación de dise o ni el flujo mismo de dise o. Por otro lado, porque toda implementación física es afectada por las no idealidades de los componentes electrónicos, se presenta el modelado de varios de ellos soportado en datos de simulación spice y resultados experimentales a manera de mostrar cómo esa información se incorpora al flujo de dise o. Una ventaja de esta propuesta es que se conserva el significado físico de toda variable de dise o. El aprendizaje basado en el trabajo de laboratorio, que es la técnica adoptada en este trabajo, ha permitido a los estudiantes comprender conceptos físicos, capturar y analizar información experimental, y usar herramientas de dise o de manera correcta para evitar aproximaciones tipo "prueba y error".
EVALUACIóN DE DIFERENTES PRUEBAS PARA EL DIAGNóSTICO DE H. PYLORI
José Ignacio Moncayo Ortiz,Adalucy álvarez Aldana,Jorge Javier Santacruz Ibarra,Mario Santacoloma Osorio
Investigaciones Andina , 2011,
Abstract: Introduction: all of the available tests for the diagnosis ofH. pylori have differences in their sensibility and specificity. The purpose of this study is to determine the developmental index, sensibility, specificity and predictable values offour invasive methods, using the case definition as a referential technique; positive culture o concordance of at least two processes ofpositive diagnostics.Methods: five biopsies were taken among seventy two patients, distributed for PCR-ureC, culture, quick ureic test (PRU) and histological examination (EH).Results: the developmental index (ID), sensibility, specificity and predictive measures showed differences. The couple EH-PCF was considerably effective, presenting the greatest values of analyzed indexes. The prevalence of infection was of 86.1%.Conclusion: in order to establish the true status of the infection by H. pylori, it is necessary to use the criteria by case definition.
Decrease in the Hospital Stay of Neonates with Suspected Nosocomial Sepsis with the Use of a Molecular Biology Technique  [PDF]
Jesús Reyna-Figueroa, María Fernanda Rodríguez-Sánchez, Pilar Miyoko Martínez Matsumoto, Federico Javier Ortiz-Ibarra, Ana Elena Limón-Rojas
Journal of Biosciences and Medicines (JBM) , 2019, DOI: 10.4236/jbm.2019.73005
Abstract: Introduction: Diagnostic alternatives that allow microbial identification in blood, such as molecular biology; have shown utility in neonatal sepsis. Objective: To evaluate the impact of a Light Cycler SeptiFast test (LCSF) on days of hospital stay and the use of newborn (NB) antibiotics with suspected sepsis. Methods: We included NB with LCSF test and blood culture (cases) and NB with only blood culture (controls). We evaluated the days of stay, days of antimicrobial use and number of deaths. Statistic analysis: Descriptive statistics was used. The association between the use of LCSF and variables such as mortality, days of stay, use of antimicrobials, and use of mechanical ventilation was analyzed by odds ratio with 95% CI. Results: We included 20 subjects in the case group and 40 in the control group. 8 (40%) of the cases were positive vs 6 (15%) of the controls in the control group. In the controls, the average days of stay were 65 + 15 vs 35 + 10 days of the cases (p < 0.05). There was no significant difference in mortality, nor in antimicrobial use. The use of molecular biology was a protective factor for prolonged stay OR 0.2 (95% CI 0.08 - 0.5) p = 0.001. Conclusions: The LCSF test influences the days of hospital stay, but does not impact mortality or the use of antimicrobials.
Eficacia de la cuantificación de interleucina- 6 en el líquido cefalorraquídeo para el diagnóstico de meningitis bacteriana neonatal
Ortiz- Ibarra, Federico Javier;Reyna- Figueroa, Jesús;Aldana- Cuevas, Rodrigo Efrén;Lara- Sánchez, Jacqueline;
Boletín médico del Hospital Infantil de México , 2005,
Abstract: introduction. a great variety of cytokines are produced locally in the central nervous system in response to microbial infection, and their levels have been used as a diagnostic parameter of infection. objectives: to determine the concentrations of interleukin- 6 (il- 6) in cerebrospinal fluid (csf) of newborns with bacterial meningitis and the effectiveness of the determination as a diagnostic tool. material and methods. this was a prospective study from december 2002 to july 2003, in the instituto nacional de perinatologia (inper), in which the concentrations of il- 6 in the csf were measurered in newborns with a clinical diagnosis of sepsis. results. fourteen out of 58 newborns attended during the study period had bacterial meningitis.the mean il- 6 concentration in the meningitis group was 9 994 pg/ml vs 15.4 pg/ml in the control group (p <0.05). sensitivity was (92%),the specificity (100%);the positive predictive value and area under the roc curve support that il- 6 concentration of >50 pg/ml in csf are the cut- off level of neonatal bacterial meningitis. the concentrations of il- 6 in the csf were greater, demonstrating itself that concentrations of il- 6 equal or greater to 50 pg/ml have a sensitivity of 92% and a specificity of 100%, for the diagnosis of bacterial meningitis. conclusions. the determination of the concentration of il- 6 in csf could be a useful tool in the meningitis diagnosis; however csf conventional analysis and culture are still the gold standard.
Antibacterial activity of chitosan and the interpolyelectrolyte complexes of poly(acrylic acid)-chitosan
Ortega-Ortiz, Hortensia;Gutiérrez-Rodríguez, Baltazar;Cadenas-Pliego, Gregorio;Jimenez, Luis Ibarra;
Brazilian Archives of Biology and Technology , 2010, DOI: 10.1590/S1516-89132010000300016
Abstract: the antimicrobial activity of chitosan and water soluble interpolyelectrolyte complexes of poly(acrylic acid)-chitosan was studied. chitosans of two different molecular weights were tested at different concentration for 0.5 to 5 g·l-1 as antimicrobial agents against p. aeruginosa and p. oleovorans. in both cases, the best microbial inhibition was obtained with the concentration of 5 g·l-1. however, the interpolyelectrolyte complexes of poly(acrylic acid)-chitosan with composition φ =2 produced higher antibacterial activity than the two chitosans at the concentration of 0.5 g·l-1. the npec2 complex was more effective than chitosans. this could be attributed to the number of moles of the amino groups of chitosan and the carboxylic acid groups of the interpolyelectrolyte complexes poly(acrylic acid).
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