510 research outputs found

    Biofunctionalized Polymer Nanomaterials: Implications on Shapes and Sizes

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    Nanotechnology has been one of the most widely used tools in various industries such as pharmaceutical, food, and chemistry, among others, for the encapsulation of compounds or even microorganisms. However, an analysis of the methodologies or polymer matrices to be used is rarely generated, and these in turn contribute to the objective of the product that is intended to be designed. In addition to the evaluation of its physicochemical, optical, and rheological characteristics, and others, are a set of technological tools that allow predicting the stability of a colloid, however, some of the factors that have less importance as the effect of the synthesis process on the shape and size that a structure may have, studies have been carried out to evaluate this phenomenon, which has become a determining factor in the design of any nanoscale material

    Water quality in the central zone of the Texcoco aquifer, Mexico

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    Objective: Determine the water quality in the central zone of the Texcoco aquifer for human use and consumption and agricultural use. Methodology: Physical, chemical and biological indicators of the water from 16 wells located in urban areas of the central zone of the aquifer were determined. Sampling, determination of the parameters and definition of its quality by uses was made based on current official Mexican standards. Results: According to the physical indicators and the concentrations of CO32-, HCO3-, Ca2+, Mg2+, Cl-, SO42-, PO43-, Na+, K+, Fe, Cu and Zn, the water was suitable for human consumption and agricultural use in the 16 wells studied. Based on the Cadmium concentration (Cd), the water was unsuitable for human consumption and agricultural use, in 12 and 6 wells, respectively. According to the found concentration of Lead (Pb), the water was suitable for agricultural use in the 16 wells studied, but in all of them it was not suitable for human consumption. Water did not meet the microbiological quality required for human consumption in eight of the wells analyzed, but was suitable for agricultural use in all the study wells. Implications: This study complements the research carried out in other areas of the aquifer. The causes of water contamination are unknown and it would be convenient to investigate the vulnerability of the aquifer and possible sources of contamination. Conclusions: The aquifer water in the central zone has limitations for human use and consumption and agricultural use due to the high concentrations of Cd, Pb and poor microbiological quality.Objective: To determine water quality in the central zone of the Texcoco aquifer, Mexico, for human use and consumption and agricultural use. Methodology: The physical, chemical, and biological indicators of the water from 16 wells in urban areas of the central zone of the aquifer were determined. The sampling was carried out, based on the parameters and definition of water quality per use established in the current official Mexican standards. Results: According to the physical indicators and concentrations of CO32-, HCO3-, Ca2+, Mg2+, Cl-, SO42-, PO43-, Na+, K+, Fe, Cu, and Zn, the water in the sample was suitable for human use and consumption and agricultural use. Based on the cadmium (Cd) concentration, the water was unsuitable for human use and consumption and agricultural use, in 12 and 6 wells, respectively. According to the lead (Pb) concentration, water was suitable for agricultural use in the 16 wells studied; however, it was unsuitable for human use and consumption in any of the wells. In eight wells analyzed, the presence of fecal coliforms was lower than the permissible limit for agricultural use. Implications: This study complements researches done in other areas of the aquifer. The causes of water pollution are unknown and researches about the vulnerability of the aquifer and the possible polluting sources should be carried out. Conclusions: The water from the aquifer in the central zone has limitations for human use and consumption and agricultural use, as a consequence of the high Cd and Pb concentrations and its microbiological quality

    Surface water balance at the Chapingo River basin: rainfall intercepted by vegetation and water infiltration into the soil

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    Objective: Estimate the surface water balance in the Chapingo river micro-basin in the period 2014 and 2016-2018 based on information collected on precipitation and runoff, the use of interception simulation models, and the remaining estimate of infiltration. Design/methodology/approach: During the wet season of 2014 and 2016-2018, the water balance in unit depths was estimated from precipitation and runoff data, interception simulation models, and estimation of infiltration as a remnant of the balance. Results: The highest interception rate was found in the year (2014) with the lowest range and least dispersion of precipitation, while the lowest interception occurred in the year (2018) with opposite characteristics of precipitation. In two of the years of study, a linear relationship was found between precipitation and surface runoff with R2 greater than 0.81. The interception rate was lower in the oyamel forest (7.7% -9.3%), the interception variation between grassland, pine forest, oak forest and agricultural area was 20% to 23%. The remaining water for infiltration represented between 85.5% and 88.2% of the precipitated water. Study limitations/implications: It is necessary to know the temporal evolution of the rainfall interception and the soil moisture to specify the potential recharge to the aquifer. Findings/conclusions: Interception is the main vehicle by which water reaches the ground in the presence of areas covered by vegetation. Precipitation intensity negatively affects interception and infiltration. The study basin offers a high recharge potential to the Texcoco aquifer.Objective: To estimate the surface water balance in the Chapingo River microbasin in the years 2014, 2016, 2017, and 2018, based on information collected on rainfall and runoff, the use of interception simulation models, and the estimation of the of infiltration as a remainder of the balance. Design/Methodology/Approach: During the 2014, 2016, 2017, and 2018 wet seasons, the water balance in unit sheet was estimated based on rainfall and runoff data, mathematical interception simulation models, and estimation of infiltration as a remainder of the balance. Results: The highest interception rate was recorded in 2014, with a shorter range and lower dispersion of rainfall, while the lowest interception occurred in 2018 with opposite rainfall characteristics. A linear relationship was found, in two years, between rainfall and surface runoff with R2 greater than 0.81. The interception rate was lower in the oyamel fir forest (7.7-9.3%), while the variation in interception between grasslands, pine forests, oak forests, and agricultural areas ranged from 20% to 23%. The remaining infiltration water represented between 85.5% and 88.2% of the rainfall. Study Limitations/Implications: Determining the temporal evolution of the interception and humidity in the soil is necessary to specify the potential recharge to the aquifer. Findings/Conclusions: Interception is the main vehicle by which water reaches the ground in areas covered by vegetation. Rainfall intensity has a negative impact on interception and infiltration. The basin under study offers a high recharge potential to the Texcoco aquifer

    Determination of cadmium and lead in water, sediment and bioindicator organisms in Estero Salado, Ecuador

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    Evidence of pollution by heavy metals have been detected in the city of Guayaquil, province of Guayas, coastal Ecuador. The water and sediment in the mangrove environs of Puente Portete in Estero Salado were tested for concentrations of cadmium (Cd) and lead (Pb), as well as the following organisms: gastropods, including Littorina varia and Cerithidea mazatlanica, and the leaves of Rhizophora racemosa, Laguncularia racemosa, Avicennia germinans, and Conocarpus erectus. The samples were analyzed using flame atomic absorption spectrophotometry. The values of Cd and Pb in water and sediment exceeded the permissible limits established by Ecuadorian and Canadian standards. The gastropod species L. varia and C. mazatlanica were the best indicator organisms for detecting pollution by accumulating 2.45 ± 0.49 ppm Pb and 1.49 ± 0.67 ppm Cd, respectively. Because of the low bioavailability of heavy metals in sediments, mangrove plants did not accumulate Cd and Pb in leaves

    Cerebral cryptococcosis: description of a series of cases of atypical clinical presentation Hospital Universitario San José Infantil de Bogotá

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    Introducción: la criptococosis cerebral (CC) es la infección fúngica más frecuente del sistema nervioso central; se presenta especialmente en pacientes con algún tipo de inmunodeficiencia, sin embargo también puede encontrarse en inmunocompetentes, casos que son más severos y con manifestaciones neurológicas variables. Si bien las manifestaciones típicas son las más frecuentes, existen manifestaciones atípicas especialmente en pacientes inmunocompetentes que pueden llegar a presentarse en un 60% de los casos según los estudios radiológicos, por lo cual es importante reconocerlas a fin de garantizar un diagnóstico temprano y una intervención oportuna. Objetivo: describir las características clínicas de presentaciones típicas y atípicas de la criptococosis cerebral en el Hospital Universitario San José Infantil de Bogotá. Materiales y métodos: reportamos una serie de casos entre marzo de 2013 y marzo de 2014 en el Hospital Universitario San José Infantil. Se describió un total de ocho casos de criptococosis cerebral. El diagnóstico, en todos los casos, se hizo conforme a los hallazgos histopatológicos o cultivos. Resultados: de los ocho pacientes descritos, seis son hombres (75%), la mayoría menores de 60 años ( =42,25 años DE 13,25); siete pacientes (87,5%) fueron inmunosuprimidos, de los cuales cinco resultaron VIH-seropositivos (62,5%). El principal motivo de consulta fue cefalea (87,5%). La clínica resultó más severa en los pacientes VIH-seronegativos. En varios pacientes se evidenciaron trastornos neuropsiquiátricos. En cinco pacientes (62,5%) se encontraron manifestaciones atípicas: criptococoma cerebral en el 25% (n = 2), ventriculitis en el 12,5% (n = 1) y trombosis séptica de senos venosos en el 25% (n = 2). Conclusión: en nuestra población con CC se evidenciaron características clínicas similares a las reportadas en otros estudios, en los que más de la mitad presentó manifestaciones atípicas, especialmente los pacientes VIHseronegativos. Adicionalmente, se encontraron varias manifestaciones neuropsiquiátricas. Se deben tener en cuenta los cambios neuropsiquiátricos y las presentaciones atípicas sobre todo en los pacientes VIH-seronegativos con el fin de realizar un diagnóstico rápido e iniciar un tratamiento oportuno para la CC.Introduction: Cerebral Cryptococcosis (CC) is the most common CNS fungal infection, it is especially in patients with some type of immunodeficiency, but can also be found in immunocompetent, being more severe and with variable neurological manifestations in that cases. While the typical manifestations are the most frequently seeing, atypical manifestations especially in immunocompetent patients, may present in 60% of cases as radiological studies, so it is important to recognize in order to ensure early diagnosis and timely intervention. Objective: to describe the clinical characteristics of typical and atypical presentations of cerebral cryptococcosis in Hospital Universitario San José Infantil de Bogotá. Materials and methods: we report a series of cases between March 2013 and March 2014 at the Hospital Universitario San Jose Infantil. A total of 8 cases of cerebral cryptococcosis described. The diagnosis in all cases was done according to the histopathological findings or cultures. Results: in 8 patients described 6 were men (75%), most under 60 years ( = 13.25 = 42.25 years), 7 patients (87.5%) were immunosuppressed, of which 5 HIV-seropositive patients (62.5%). The main complaint was headache (87.5%). The clinical manifestations was more severe in HIV-seronegative patients. Several patients showed neuropsychiatric disorders. In 5 patients (62.5%) atypical manifestations were found: cryptococcoma brain in 25% (n = 2), ventriculitis in 12.5% (n = 1) and septic venous sinus thrombosis in 25% (n = 2). Conclusion: in our population CC was similar to those reported in other studies, where more than half had atypical manifestations especially HIV-seronegative. Additionally several neuropsychiatric manifestations were found. Physicians should consider neuropsychiatric changes and atypical presentations essentially in HIVseronegative patients in order to make a quick diagnosis and initiate early treatment for CC

    Re-establishment of the genus Pseudalbizzia (Leguminosae, Caesalpinioideae, mimosoid clade): the New World species formerly placed in Albizia

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    Following recent mimosoid phylogenetic and phylogenomic studies demonstrating the non-monophyly of the genus Albizia, we present a new molecular phylogeny focused on the neotropical species in the genus, with much denser taxon sampling than previous studies. Our aims were to test the monophyly of the neotropical section Arthrosamanea, resolve species relationships, and gain insights into the evolution of fruit morphology. We perform a Bayesian phylogenetic analysis of sequences of nuclear internal and external transcribed spacer regions and trace the evolution of fruit dehiscence and lomentiform pods. Our results find further support for the non-monophyly of the genus Albizia, and confirm the previously proposed segregation of Hesperalbizia, Hydrochorea, Balizia and Pseudosamanea. All species that were sampled from section Arthrosamanea form a clade that is sister to a clade composed of Jupunba, Punjuba, Balizia and Hydrochorea. We find that lomentiform fruits are independently derived from indehiscent septate fruits in both Hydrochorea and section Arthrosamanea. Our results show that morphological adaptations to hydrochory, associated with shifts into seasonally flooded habitats, have occurred several times independently in different geographic areas and different lineages within the ingoid clade. This suggests that environmental conditions have likely played a key role in the evolution of fruit types in Albizia and related genera. We resurrect the name Pseudalbizzia to accommodate the species of section Arthrosamanea, except for two species that were not sampled here but have been shown in other studies to be more closely related to other ingoid genera and we restrict the name Albizia s.s. to the species from Africa, Madagascar, Asia, Australia, and the Pacific. Twenty-one new nomenclatural combinations in Pseudalbizzia are proposed, including 16 species and 5 infraspecific varietal names. In addition to the type species Pseudalbizzia berteroana, the genus has 17 species distributed across tropical regions of the Americas, including the Caribbean. Finally, a new infrageneric classification into five sections is proposed and a distribution map of the species of Pseudalbizzia is presented

    Temporal distribution and genetic variants in influenza A(H1N1)pdm09 virus circulating in Mexico, seasons 2012 and 2013

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    The 2012 and 2013 annual influenza epidemics in Mexico were characterized by presenting different seasonal patterns. In 2012 the A(H1N1)pdm09 virus caused a high incidence of influenza infections after a two-year period of low circulation; whereas the 2013 epidemic presented circulation of the A(H1N1)pdm09 virus throughout the year. We have characterized the molecular composition of the Hemagglutinin (HA) and Neuraminidase (NA) genes of the A(H1N1)pdm09 virus from both epidemic seasons, emphasizing the genetic characteristics of viruses isolated from Yucatan in Southern Mexico. The molecular analysis of viruses from the 2012 revealed that all viruses from Mexico were predominantly grouped in clade 7. Strikingly, the molecular characterization of viruses from 2013 revealed that viruses circulating in Yucatan were genetically different to viruses from other regions of Mexico. In fact, we identified the occurrence of two genetic variants containing relevant mutations at both the HA and NA surface antigens. There was a difference on the temporal circulation of each genetic variant, viruses containing the mutations HA-A141T / NA-N341S were detected in May, June and July; whereas viruses containing the mutations HA-S162I / NAL206S circulated in August and September. We discuss the significance of these novel genetic changes

    Memorias : Coloquio los Métodos en el Diseño y la Arquitectura

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    1 archivo PDF (190 páginas)Memorias del Coloquio Departamental Los Métodos en el Diseño y la Arquitectura, el cual tuvo dos objetivos: el primero, mostrar las reflexiones en tomo a las metodologías en el diseño y la arquitectura que utilizan los profesores tanto en la investigación como en la docencia, y el segundo, exponer ante los alumnos el trabajo previo que los profesores realizan para impartir las Unidades de Enseñanza Aprendizaje en el salón de clases

    Filogenia de Lysiloma (Fabaceae), un género restringido a Megaméxico con especies atípicas en las Antillas y Florida

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    Background and Aims: Lysiloma is a Neotropical genus in the Fabaceae family that comprises eight species, six of which are widely distributed in Mexico, and two more that occur in the Antilles and Florida. Lysiloma is frequent in Megamexico’s dry forests. A previous phylogenetic study included three species of Lysiloma and Hesperalbizia occidentalis. Both genera are closely related, but their divergence has weak support. Our objectives were to test the monophyly of the genus, evaluate the sister relationships within the genus, and estimate the divergence times. Methods: A phylogenetic analysis based on morphological characters, molecular markers (ETS, matK, and trnK), as well as a combined analysis (morphology + molecules) was performed. The data matrices were analyzed both individually and concatenated (total evidence approach) with Bayesian inference and Maximum Parsimony. In addition, molecular divergence times were estimated from the ETS dataset with a Bayesian uncorrelated lognormal relaxed clock. Key results: The morphological analysis supports the monophyly of Lysiloma with Hesperalbizia as sister group. However, the individual and the combined molecular analyses do not provide resolution to clarify the relationships between Hesperalbizia occidentalis, Lysiloma sabicu, and core Lysiloma. The total evidence analysis (including morphology) supports the monophyly of Lysiloma, yet with low support. According to our molecular clock model, the clade Lysiloma+Hesperalbizia diverged from other members of the tribe Acacieae+Ingeae about 32 million years ago, and the diversification of the core of Lysiloma occurred during the Miocene. Conclusions: Lysiloma+Hesperalbizia is an early divergent clade of tribes Acacieae+Ingeae. There are enough morphological differences to recognize both linages. Morphological characters informally used for taxonomic delimitation seem to have evolved homoplasiously. The clade Lysiloma and Hesperalbizia separated from other members of the tribe Acacieae+Ingeae in the Oligocene, but the diversification of the core of the genus coincides with the expansion of the dry forest at the beginning of the Miocene.Antecedentes y Objetivos: Lysiloma es un género neotropical de la familia Fabaceae que comprende ocho especies, seis de las cuales se distribuyen ampliamente en México y dos más que ocurren en las Antillas y La Florida. Lysiloma es frecuente en los bosques secos de Megaméxico. Un estudio filogenético previo incluyó tres especies de Lysiloma y Hesperalbizia occidentalis. Ambos géneros están estrechamente relacionados, pero su divergencia tiene un apoyo débil. Nuestros objetivos fueron probar la monofilia del género, evaluar las relaciones de grupo hermano dentro del género y estimar los tiempos de divergencia. Métodos: Se realizó un análisis filogenético basado en caracteres morfológicos, marcadores moleculares (ETS, matK y trnK), así como un análisis combinado (morfología + moléculas). Las matrices de datos se analizaron tanto individualmente como concatenadas (enfoque de evidencia total) con inferencia Bayesiana y máxima parsimonia. Además, los tiempos de divergencia molecular se estimaron a partir del conjunto de datos ETS con un modelo de reloj bayesiano relajado lognormal no correlacionado. Resultados clave: El análisis morfológico respalda la monofilia del Lysiloma con Hesperalbizia como grupo hermano. Sin embargo, los análisis moleculares individuales y combinado no proporcionan resolución para aclarar las relaciones entre Hesperalbizia occidentalis, Lysiloma sabicu y el núcleo de Lysiloma. El análisis de evidencia total (incluida la morfología) respalda la monofilia de Lysiloma, pero con un bajo soporte. Según nuestro modelo de reloj molecular, el clado Lysiloma+Hesperalbizia se separó de otros miembros de la tribu Acacieae+Ingeae hace unos 32 millones de años y la diversificación del núcleo del Lysiloma se produjo a lo largo del Mioceno.Conclusiones: Lysiloma+Hesperalbizia es un clado de divergencia temprana de las tribus Acacieae+Ingeae. Existen suficientes diferencias morfológicas para reconocer ambos linajes. Los caracteres morfológicos utilizados informalmente para la delimitación taxonómica parecen haber evolucionado de manera homoplásica. El clado de Lysiloma y Hesperalbizia se separó de otros miembros de la tribu Acacieae+Ingeae en el Oligoceno, pero la diversificación del núcleo del género coincidió con la expansión del bosque seco a principios del Mioceno

    Lenguajeando mediación pedagógica

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    PublishedSi lo titulado anteriormente debiera ubicarse dentro de lo que la metodología tradicional considera como un ‘Resumen’, a continuación va entonces lo que en clave podría referirse sobre las ‘Palabras Clave’: brotes porque es lo que surge de las tierras, enacción quizá en el mejor sentido inglés de ‘to enact’, y rizomas en razón de los nacientes tejidos. Anotando al respecto que, si bien Deleuze (2005) acuñó el término en Francia en medio de sus referentes biológicos, es aquí en nuestra denominada Latinoamérica donde los rizomas los hemos ‘platanizado’. Porque aquí los hemos vivenciado y encontrado, hurgando con los dedos entre la tierra. A veces árida y en espera de las gotas de lluvia
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