1,225 research outputs found

    A 0.18um CMOS Time Amplifier for a Low Power SAR-ADC with Adaptive Conversion Cycle oriented to Audio Applications

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    This document presents the design of a time amplifier circuit in 0.18 m CMOS process with a supply voltage of 1.8 V. Simulation results performed with typical process parameters, nominal supply voltage, room temperature and an operating frequency of 200 KHz, show a time gain of 200, with an error of less than 7%. The power consumption of the designed circuit is 26 W. The circuit can receive signals with a time difference from 10 ps to 4.7 nS. The layout dimension is 149.985 m x 168.536 m, with an area of 25.3 nm2.ITESO, A. C

    Implementing Time Amplifier for a Low Power SAR-ADC with Adaptive Conversion Cycle for High Quality Audio Applications in 0.18um TSMC CMOS Technology

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    This document presents the design of a time amplifier circuit in 0.18 m CMOS process with a supply voltage of 1.8 V. Simulation results performed with typical process parameters, nominal supply voltage, room temperature and an operating frequency of 200 KHz, show a time gain of 200, with an error of less than 7%. The power consumption of the designed circuit is 26 W. The circuit can receive signals with a time difference from 10 ps to 4.7 nS. The layout dimension is 149.985 m x 168.536 m, with an area of 25.3 nm2.ITESO, A. C

    El uso de las TIC en el proceso de enseñanza de las matemáticas en bachillerato

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    Theoretical foundation: The literature supports the use of ICT in mathematics education as a means to enhace teaching and learning processes, however, addressing the challenges associated with the integration of ICT in mathematics education is essential to maximize its benefits. Objective: Determine the relationship between the use of ICT by mathematics teachers and the gender, ethnicity and liking for mathematics of high school students. Methodology: This research employed a non-experimental, descriptive and relational approach, A survey instrument with a Cronbach's Alpha of 0.79 was utilized and administered to 1882 high school students from urban and rural areas. The data were analyzed using descriptive and inferential statistical methods with the SPSS v.25 software. Results: Statistically significant relationships were found in two of the three proposed hypotheses with a significance level of 0.05. Conclusions: Students' attitudes towards mathematics can be influenced by the level of ICT use by subject teachers, emphasizing the need for specific strategies to support mathematics education.Fundamentación: La literatura apoya el uso de las TIC en la educación matemática como un medio para mejorar los procesos de enseñanza y aprendizaje, sin embargo, abordar los desafíos asociados con la integración de las TIC en la educación matemática es esencial para maximizar sus beneficios. Objetivo: Determinar la relación entre el uso de TIC por parte de los docentes de matemáticas y el género, la etnia y el gusto por las matemáticas de estudiantes de bachillerato. Metodología: La investigación es no experimental, de tipo descriptivo y relacional; el instrumento presentó un Alfa de Cronbach de 0,79 y se suministró a 1882 estudiantes de bachillerato del cantón Ibarra de 6 instituciones educativas de los sectores urbano y rural; para el análisis estadístico descriptivo e inferencial se empleó el programa informático SPSS v.25. Resultados: Se encontraron relaciones estadísticamente significativas en dos de las tres hipótesis propuestas con un nivel de significancia de 0,05. Conclusiones: Las actitudes de los estudiantes hacia las matemáticas pueden verse influenciadas por el nivel de uso de las TIC por parte de los docentes de la asignatura, lo que pone de relieve la necesidad de estrategias específicas para apoyar la educación matemática

    APRIL: A double-blind, placebo-controlled, randomized, Phase Ib/IIa clinical study of ApTOLL for the treatment of acute ischemic stroke

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    Inflammation; Neuroprotection; StrokeInflamació; Neuroprotecció; IctusInflamación; Neuroprotección; IctusIn the reperfusion era, a new paradigm of treating patients with endovascular treatment (EVT) and neuroprotective drugs is emerging as a promising therapeutic option for patients with acute ischemic stroke (AIS). In this context, ApTOLL, a Toll-like receptor 4 (TLR4) antagonist with proven neuroprotective effect in preclinical models of stroke and a very good pharmacokinetic and safety profile in healthy volunteers, is a promising first-in-class aptamer with the potential to address this huge unmet need. This protocol establishes the clinical trial procedures to conduct a Phase Ib/IIa clinical study (APRIL) to assess ApTOLL tolerability, safety, pharmacokinetics, and biological effect in patients with AIS who are eligible for EVT. This will be a multicenter, double-blind, randomized, placebo-controlled, Phase Ib/IIa clinical study to evaluate the administration of ApTOLL together with EVT in patients with AIS. The study population will be composed of men and non-pregnant women with confirmed AIS with a <6h window from symptoms onset to ApTOLL/placebo administration. The trial is currently being conducted and is divided into two parts: Phase Ib and Phase IIa. In Phase Ib, 32 patients will be allocated to four dose ascending levels to select, based on safety criteria, the best two doses to be administered in the following Phase IIa in which 119 patients will be randomized to three arms of treatment (dose A, dose B, and placebo).The study is supported by grants from the Spanish Ministry of Science, Innovation and Universities (RTC-2017-6651-1 and RTC2019-006795-1). The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication

    Temperature-mediated biosynthesis of the phytotoxin phaseolotoxin by Pseudomonas syringae pv. phaseolicola depends on the autoregulated expression of the phtABC genes

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    Abstract Pseudomonas syringae pv. phaseolicola produces phaseolotoxin in a temperature dependent manner, being optimally synthesized between 18˚C and 20˚C, while no detectable amounts are present above 28˚C. The Pht cluster, involved in the biosynthesis of phaseolotoxin, contains 23 genes that are organized in five transcriptional units. The function of most of the genes from the Pht cluster is still unknown and little information about the regulatory circuitry leading to expression of these genes has been reported. The purpose of the present study was to investigate the participation of pht genes in the regulation of the operons coded into the Pht cluster. We conducted Northern blot, uidA fusions and reverse transcription-PCR assays of pht genes in several mutants unable to produce phaseolotoxin. This allowed us to determine that, in P. syringae pv. phaseolicola NPS3121, genes phtABC are essential to prevent their own expression at 28˚C, a temperature at which no detectable amounts of the toxin are present. We obtained evidence that the phtABC genes also participate in the regulation of the phtD, phtM and phtL operons. According to our results, we propose that PhtABC and other Pht product activities could be involved in the synthesis of the sulfodiaminophosphinyl moiety of phaseolotoxin, which indirectly could be involved in the transcriptional regulation of the phtA operon

    Causas de retratamiento endodontal.

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    Todo tratamiento odontológico está sujeto a complicaciones. En la endodoncia estas pueden ocurrir principalmente por una iatrogenia del operador o por falta de un procedimiento restaurador definitivo. Al presentarse está indicado realizar un retratamiento endodontal. El objetivo del estudio fue identificar la causa más común de retratamiento endodontal dentro de la clínica de pregrado de la Facultad de Odontología.Se realizó un estudio descriptivo donde se seleccionaron de manera aleatoria 50 expedientes clínicos de pacientes que recibieron retratamiento durante el periodo enero 2013 a enero 2015 en una hoja de captura de datos. Se capturaron las principales causas de retratamiento: filtración coronal, subobturación, tratamiento inconcluso y sobreobturación.Se encontró como principal causa la filtración coronal con un 70%, seguido de las piezas dentales  con una subobturación 18%, tratamiento inconcluso con 10% y por último como menos frecuente fue la sobreobturación de piezas tratadas endodonticamente con 2%.Se concluyó que la causa más frecuente de retratamiento endodontal fue la filtración coronal

    Flora y vegetación de la región semiárida de Acultzingo-Maltrata, Veracruz, México

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    Background and Aims: In the central area of the state of Veracruz there is a semi-arid region, located mainly in the municipalities Acultzingo and Maltrata, within the Cañón del Río Blanco National Park. This region had remained unexplored from the botanical point of view and had therefore not been recorded by botanical literature. The aim of this research is to contribute to the knowledge of flora and vegetation of this region, through a floristic analisis and a description of its plant communities.Methods: Periodic collections of plants from August 2012 to July 2014 were undertaken. Additionally, the CORU and MEXU herbaria were reviewed, as well as the Flora of Veracruz series, to obtain historical records in the study area. In order to determine the taxa shared between this semiarid region and the Tehuacán-Cuicatlán Valley, a presence-absence matrix and a table summarizing the shared taxa were elaborated.Key results: Six hundred and four voucher specimens were collected, 45 records from CORU, 280 from MEXU and 80 from the review of the Flora of Veracruz series were obtained, resulting in a total of 1009 records. These data corresponded to 87 families, 247 genera and 390 taxa. The best-represented families are Asteraceae, Fabaceae, Apocynaceae, Cactaceae, Asparagaceae, Boraginaceae, Bromeliaceae, Orchidaceae and Verbenaceae. Thirty-three species were considered as new records for the state of Veracruz and 43 have a threat status in terms of national and international laws. Three different vegetal associations conforming the xerophytic scrub are extensively described.Conclusions: There are 63 species shared between the study area and the Tehuacán-Cuicatlán valley, thereby confirming the floristic relationships between these two large semi-arid regions; hence, we propose the name “Acultzingo-Tehuacán-Cuicatlán Valley”, covering the states of Veracruz, Puebla and Oaxaca.Antecedentes y Objetivos: En la porción central del estado de Veracruz existe una región semiárida, en los municipios Acultzingo y Maltrata, que forma parte del Parque Nacional Cañón del Río Blanco. Esa zona había permanecido inexplorada desde el punto de vista botánico, por lo que no estaba registrada en la literatura contemporánea. El objetivo de esta investigación es contribuir al conocimiento de la flora y vegetación de esta región, a través de un análisis florístico y una descripción de las comunidades vegetales.Métodos: Se realizaron colectas periódicas de la flora entre agosto 2012 y julio 2014. Se revisaron los herbarios CORU y MEXU, así como la serie Flora de Veracruz para obtener los registros históricos en el área de estudio. Para determinar los taxones compartidos entre esta región semiárida y el Valle de Tehuacán-Cuicatlán, se realizó una matriz de presencia-ausencia y se elaboró un cuadro que los resume.Resultados clave: En total se colectaron 604 especímenes de herbario, se obtuvieron 45 registros de la revisión de CORU, 280 de MEXU y 80 de la revisión de la serie Flora de Veracruz, para un total de 1009 registros. Estos registros comprenden 87 familias, 248 géneros y 390 taxones; las familias mejor representadas son Asteraceae, Fabaceae, Apocynaceae, Cactaceae, Asparagaceae, Boraginaceae, Bromeliaceae, Orchidaceae y Verbenaceae. Se reportan 33 especies como nuevos registros para Veracruz y 43 especies incluidas en categorías de riesgo según normas nacionales e internacionales. Se describen tres asociaciones vegetales que integran al matorral xerófilo de esta área.Conclusiones: Existen 63 especies compartidas entre la región semiárida de Acultzingo-Maltrata y el Valle de Tehuacán-Cuicatlán, confirmándose así las relaciones florísticas entre estas dos grandes regiones, por lo que se propone se denomine “Valle de Acultzingo-Tehuacán-Cuicatlán”, abarcando los estados de Veracruz, Puebla y Oaxaca

    Modelo de capacitación pedagógica para planear el proceso de enseñanza aprendizaje del nivel superior

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    Project is Linking education with competency knowledge, skills and attitudes on social context. Mixed descriptive research to improve teaching and learning process. Trained teachers with enough discipline and without didactic pedagogical training, support teaching-learning process in traditional method; absence of educational planning, which prevents proper development of the educational process reflected in the quality of teaching students. The development and implementation of a model in teacher training will.La educación por competencias vincula conocimientos, habilidades y actitudes bajo contexto social. Investigación descriptiva mixta para mejorar la enseñanza aprendizaje. Docentes con formación disciplinar suficiente y carecen de formación pedagógica didáctica, soportan proceso de enseñanza aprendizaje en método tradicional; carecen de planeación didáctica, que impide un desarrollo adecuado del proceso educativo reflejado en la calidad de la enseñanza en estudiantes. La elaboración y puesta en práctica de un modelo en capacitación pedagógica en este enfoque, contribuirá a mejorar el desempeño docente. Métodos teóricos y empíricos permitieron triangular información y mayor acercamiento a la realidad investigada. Validación del modelo por expertos, determinó Coeficientes para emitir un juicio de calidad, resultando Muy Apropiada para su instrumentación en la Universidad Autónoma de Nayarit
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