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Search Results: 1 - 10 of 177307 matches for " Silvia E. Ibarra-Obando "
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Presence of Sargassum horneri at Todos Santos Bay, Baja California, Mexico: Its Effects on the Local Macroalgae Community  [PDF]
Giuliana I. Cruz-Trejo, Silvia E. Ibarra-Obando, Luis E. Aguilar-Rosas, Miriam Poumian-Tapia, Elena Solana-Arellano
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.617271
Abstract: To describe the annual cycle of Sargassum horneri in Mexican waters, we selected two sites differing in their degree of wave exposure and sediment type: Rincón de Ballenas (RB), and Rancho Packard (RP). From June 2009 to April 2010 we followed the seasonal changes in S. horneri density and biomass along two intertidal transects per site. The effects of this non-indigenous species on the local macroalgae community were assessed by comparing their species composition, density, biomass, species richness, and diversity index in quadrats with and without S. horneri. There were significant differences in S. horneri density and biomass between sites (P < 0.001). At RB the invasive alga density average was 2 ± 0.94 individual m-2, with a mean biomass of 4 ± 0.95 g DW m-2. At RP, S. horneri density average was 10 ± 0.96 individual m-2, and mean biomass of 102 ± 0.97 g DW m-2. At RB, the invasive alga promoted a significant reduction in the four selected structural variables, and the corticated macrophytes and the foliose functional forms were severely reduced. At RP, there were only marginally significant effects (P = 0.06) of S. horneri presence on the local macroalgae community, and higher density, biomass, and diversity values were found when S. horneri was present. Most of the functional forms were found, even if the invasive alga was present. At both locations, the highest biomass corresponded to the articulated calcareous functional form. These contrasting results could be due to the fact that the native macroalgae community has already been altered by the early invasion of S. muticum, with the most resilient species and functional forms remaining in place. One of the most important changes we noticed is the severe reduction of the canopy forming species at both sites.
EFECTOS DE LAS PROPIEDADES FUNDAMENTALES DE AMPICILINA MATERIA PRIMA EN LAS PROPIEDADES DERIVADAS
BENAVIDES A.,Julie F.; IBARRA J.,Esther J.; OBANDO M.,érica J.; PéREZ L.,Juliana; TOBóN Z.,Gloria E.; FLóREZ A.,óscar A.;
Vitae , 2007,
Abstract: antimicrobial agents often generate doubts concerning their therapeutic effects; it is not infrequent to find differences in the clinical effectiveness among products of the same active principle made by different laboratories. it is, therefore, necessary to carry out studies as to the reasons of such variations in order to reduce or eliminate differences in the therapeutic products. we evaluated the fundamental characteristics (external form, internal structure, and physical and chemical identification) of ampicillin powder using a trade name product (powder in capsules), a generic one (powder in capsules), as well as different crystalline forms of the raw material (also in powder), obtained by recrystallization in different solvents at room temperature. after determining the fundamental properties of the aforementioned solids, they were compared on the basis of the results obtained in their derivative properties such as the dissolution profiles analyzed by means of the difference and similarity factors (f1, f2), and the antimicrobial effectiveness indexes by means of the minimal inhibitory concentration (mic).
Migrantes mexicanos en la industria del vestido de Los ángeles.
Guillermo E. Ibarra Escobar
Migraciones internacionales , 2003,
Abstract: Este ensayo analiza la participación de la fuerza de trabajo inmigrante mexicana en la manufactura del vestido de Los ángeles. Se estudia su composición por sexo, estado de origen, perfil socioeconómico, inserción laboral y salarios. El análisis de los datos de una encuesta aplicada en el distrito manufacturero de esta ciudad, llamado Fashion District, en el 2000 muestra cambios importantes en esta población. En primer lugar, se percibe el predominio de mexicanos indocumentados de reciente arribo con un nivel bajo de capital humano. En segundo, se observa una creciente masculinización de la fuerza de trabajo, mediante la sustitución de mujeres por hombres jóvenes y de estados de origen diferentes a los de la región tradicional de migración en México. Finalmente, se encontró que la operación de redes de solidaridad entre los trabajadores mexicanos posibilita su inserción en el mercado de trabajo pero en condiciones cada vez más precarias.
EFECTOS DE LAS PROPIEDADES FUNDAMENTALES DE AMPICILINA MATERIA PRIMA EN LAS PROPIEDADES DERIVADAS EFFECTS OF THE FUNDAMENTAL PROPERTIES OF AMPICILLIN RAW MATERIAL IN THE DERIVATIVE PROPERTIES
Julie F. BENAVIDES A.,Esther J. IBARRA J.,érica J. OBANDO M.,Juliana PéREZ L.
Vitae , 2007,
Abstract: Los agentes antimicrobianos son, con frecuencia, los productos que generan más dudas en cuanto su efecto terapéutico, ya que no son pocos los casos en los cuales se ha presentado diferente eficacia clínica entre productos de un mismo principio activo pero de diferentes laboratorios; por lo tanto, es necesario realizar estudios que puedan proporcionar respuestas al por qué de estas variaciones en estos principios activos, y que apunten a acabar o, por lo menos, reducir,las eventuales diferencias entre estos productos terapéuticos. En este sentido, este trabajo busca evaluar los resultados de las características fundamentales (forma externa, estructura interna, e identificación física y química) de ampicilina en polvo, utilizando un producto de marca (polvo en cápsulas), uno genérico (polvo en cápsulas), y diferentes formas cristalinas de la materia prima (en polvo), obtenidas por recristalización en diferentes solventes y a temperatura ambiente. Luego de determinar las propiedades fundamentales de todos los sólidos anteriores, se comparan entre sí basados en los resultados obtenidos en propiedades derivadas como son los perfiles de disolución, analizados por medio de los factores de diferencia y de similitud (f1, f2), y los índices de eficacia microbiana (por medio de la concentración mínima inhibitoria, CMI). Antimicrobial agents often generate doubts concerning their therapeutic effects; it is not infrequent to find differences in the clinical effectiveness among products of the same active principle made by different laboratories. It is, therefore, necessary to carry out studies as to the reasons of such variations in order to reduce or eliminate differences in the therapeutic products. We evaluated the fundamental characteristics (external form, internal structure, and physical and chemical identification) of ampicillin powder using a trade name product (powder in capsules), a generic one (powder in capsules), as well as different crystalline forms of the raw material (also in powder), obtained by recrystallization in different solvents at room temperature. After determining the fundamental properties of the aforementioned solids, they were compared on the basis of the results obtained in their derivative properties such as the dissolution profiles analyzed by means of the difference and similarity factors (f1, f2), and the antimicrobial effectiveness indexes by means of the minimal inhibitory concentration (MIC).
Physicochemical, Antimicrobial and Antioxidant Properties of Chitosan Films Incorporated with Carvacrol
Marco A. López-Mata,Saul Ruiz-Cruz,Norma P. Silva-Beltrán,José de Jesús Ornelas-Paz,Paul B. Zamudio-Flores,Silvia E. Burruel-Ibarra
Molecules , 2013, DOI: 10.3390/molecules181113735
Abstract: Chitosan films (CF) with carvacrol (CAR) [0.5%, 1.0% and 1.5% v/v] were prepared by the emulsion method. The retained CAR, water solubility, water vapor permeability (WVP), optical, mechanical properties, antibacterial and antioxidant capacity of films were analyzed. The results indicate that the retention of CAR in the CF was ≈50%. The incorporation of CAR to CF decreased the water solubility, the WVP, the yellowing and transparency and the tensile strength, but increased the stiffness. Microcapsules with diameters of 2 to 7 μm were found on the surface CF-CAR. The CF-CAR with highest CAR concentrations showed antibacterial activity against S. t yphimurium and E. coli O157:H7. The CF-CAR had higher antioxidant capacity and an increased protective effect against oxidation of erythrocytes in different grades. These results suggest potential applications of CF-CAR as active packaging to preserve food products.
Applicable Quality Models in Higher Education in Argentina  [PDF]
Lidia Giuffré, Silvia E. Ratto
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.410A005
Abstract: The aim of this paper is the study of quality management systems applied to higher education. The specific objectives are to present different models of approach to the concept of quality education applicable in Argentina: to study the legal framework governing university education, and to introduce considerations about its evaluation. The National Education Law 26026/2006 is clear about State responsibility to ensure quality education for all residents, and implementation of assessment policy to secure it. Accreditation is the process commonly used to give public account of the degree of compliance of higher education institutions. Periodic accreditation of undergraduate careers, whose titles correspond to professions regulated by the State, is performed. External evaluations present evaluation reports that are public.
Some Remarks and Experiences on Higher Education and Sustainable Development  [PDF]
Lidia Giuffré, Silvia E. Ratto
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.43017
Abstract: Education for sustainable development should be based on proper environmental management. The general objective of this study is to highlight key aspects of environmental education, with specific objectives. Inclusive education addresses the learning needs with a focus on those who are vulnerable to marginalization and exclusion. Ethics plays a vital role in environmental management and should be a cornerstone to raise awareness of new forms of relationship with the particular and global environment. The cosmovision of indigenous peoples should be respected, including the indissoluble union of each culture with the environment. The feminization of labor is relevant in horticulture crops, with an active role of women in the organization of work. The connections between education and the world of work are key, with preparation for new and indeterminate forms of employment, paying attention to social skills in the context of increasing globalization. University Social Responsibility (USR) implies that the University must act ethically in knowledge transfer, promoting sustainable development. Sustainable development involves new systems of thought, it requires creativity and critical thinking, and an alternative is the creation of role-playing, to lead people to thinking in different ways. It is essential that the new professionals act without static patterns, integrating interdisciplinary teams, to search for the answer to a problem, offering original and innovative alternatives.
Sobre la primitiva organización gentilicia
Ibarra Grosso, I.E
Bulletin de l'Institut Francais d'études Andines , 1973,
Abstract: L'A. établit la relation entre l'organisation gentilice grecque et romaine et le calendrier de ces peuples. Il montre également la relation entre l'organisation gentilice des indiens nord-américains et un modèle prédéterminé de huit 'gens' pour chaque tribu. Il démontre finalement le caractère décimal de l'organisation gentilice inca qui s'oppose a l'organisation aztèque de type vicésimal liée a son calendrier. En raison de tout ceci, l'A. conclut que le modèle général gentilice de ces peuples est de caractère mythique, rejetant ainsi le concept qui veut que l'organisation gentilice typique se forme a partir de l'évolution naturelle des organisations familiales primitives. Se establece la relación existente entre la organización gentilicia griega y romana con el calendario usado por estos pueblos. Asimismo la relación existente entre la organización gentilicia de los indios norteamericanos y un patrón predeterminado de ocho gens para cada tribu. Finalmente se establece el carácter decimal de la organización gentilicia incaica, en contraposición a la vigesimal azteca que se relaciona con el calendario usado en esta cultura. Con esta evidencia se concluye en que el patrón general gentilicio de estos pueblos es de carácter mítico, rechazándose así el concepto de que la organización gentilicia típica se forma por la evolución natural de las organizaciones familiares primarias.
El diesel para autotransporte en México. Situación actual y prospectiva
Eunice Leticia Taboada Ibarra,Silvia Guadalupe Osnaya García
El Cotidiano , 2009,
Abstract: Aunque nuestras refinerías todavía no están preparadas para producir la gasolina y el diesel de ultra bajo contenido de azufre que exige la normatividad ambiental, y que es requisito indispensable para introducir nuevos motores de tecnología avanzada para reducir las emisiones a la atmósfera, la tendencia en el uso creciente de diesel como combustible en el autotransporte seguirá en aumento. Las marcas que ya han introducido vehículos a diesel en el país, buscarán fortalecer su presencia en el mercado, sobre todo al promover que este tipo de combustible, además de garantizar mayor durabilidad a los sistemas avanzados de control de emisiones, contribuye a reducir las emisiones vehiculares y la concentración de contaminantes en la atmósfera.
El inversor CMOS y su uso en el dise o de sistemas de mayor complejidad
F. Sandoval Ibarra,E. Montoya Suárez
Revista mexicana de física , 2004,
Abstract: En este artículo se presenta el dise o de sistemas digitales a partir del uso de un circuito inversor básico, denominado de aquí en adelante celda básica. El propósito no solo es mostrar la utilidad de la celda en el dise o de sistemas de mayor complejidad sino también mostrar las consideraciones de dise o y de pruebas útiles en el proceso de caracterización de los sistemas bajo análisis. Los circuitos mostrados fueron fabricados en una tecnología CMOS, 1.21m, pozo N.
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