60 research outputs found

    Expansión Urbana y cambios de cobertura /uso del suelo en Playa del Carmen, Quintana Roo, México (1985-2015)

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    Los cambios de cobertura y uso del suelo han contribuido a la configuración del espacio geográfico. La urbanización es uno de los principales procesos de cambio que ha ocasionado la transformación de los paisajes naturales. Este estudio presenta la evaluación de los cambios de cobertura y usos del suelo originados por la expansión urbana en Playa del Carmen, Quintana Roo (México), durante el periodo 1985-2015. Esto se realizó mediante el cálculo de indicadores y tasas de cambio obtenidos de una matriz de cambios y mapas de cobertura y uso del suelo. Estos últimos se elaboraron a partir de imágenes del Google Earth de los años 1985, 1990, 1995 y 2000, una ortofoto digital del año 2004 e imágenes satelitales QuickBird y WorldView-3 de los años 2007 y 2015 respectivamente. Los resultados muestran que el proceso de urbanización de Playa del Carmen ha ocasionado la pérdida de 2,514.6 hectáreas (ha) de vegetación natural durante el periodo 1985-2015. Entre 2004 y 2015 esta misma cobertura disminuyó 1,080.7 ha, producto del aumento de los usos de suelo urbano. Se concluye que, en un periodo de 30 años, el crecimiento urbano de Playa del Carmen registró una tasa de cambio anual de 11.6% (aumentó 2,514.6 ha), situación que se atribuye al crecimiento demográfico ocasionado por la oferta de trabajo que demandan los servicios turísticos de esta ciudad, generando con ello el aumento de zonas de uso residencial y áreas destinadas a la construcción de equipamiento urbano.Los cambios de cobertura y uso del suelo han contribuido a la configuración del espacio geográfico. La urbanización es uno de los principales procesos de cambio que ha ocasionado la transformación de los paisajes naturales. Este estudio presenta la evaluación de los cambios de cobertura y usos del suelo originados por la expansión urbana en Playa del Carmen, Quintana Roo (México), durante el periodo 1985-2015. Esto se realizó mediante el cálculo de indicadores y tasas de cambio obtenidos de una matriz de cambios y mapas de cobertura y uso del suelo. Estos últimos se elaboraron a partir de imágenes del Google Earth de los años 1985, 1990, 1995 y 2000, una ortofoto digital del año 2004 e imágenes satelitales QuickBird y WorldView-3 de los años 2007 y 2015 respectivamente. Los resultados muestran que el proceso de urbanización de Playa del Carmen ha ocasionado la pérdida de 2,514.6 hectáreas (ha) de vegetación natural durante el periodo 1985-2015. Entre 2004 y 2015 esta misma cobertura disminuyó 1,080.7 ha, producto del aumento de los usos de suelo urbano. Se concluye que, en un periodo de 30 años, el crecimiento urbano de Playa del Carmen registró una tasa de cambio anual de 11.6% (aumentó 2,514.6 ha), situación que se atribuye al crecimiento demográfico ocasionado por la oferta de trabajo que demandan los servicios turísticos de esta ciudad, generando con ello el aumento de zonas de uso residencial y áreas destinadas a la construcción de equipamiento urbano.Universidad de Quintana Roo (Campus Chetumal) CONACYT

    Ara militaris en el centro-occidente de Veracruz: registros recientes

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    Based on interviews and field observations, we present information about individuals of Military Macaw (Ara militaris) in the common of Caballo Blanco, in central western of Veracruz. We obtained observations in 2014 and 2015 on a site with cliffs covered by deciduous forest relicts. However, local people said they had seen Military Macaws in this area at least since 2012. It is important to continue working with the people of Caballo Blanco in order to ensure the preservation of this population of Military Macaw. Also, it is necessary to deepen aspects of their ecology on this site, which would be the only one with recent and constant presence of this species in Veracruz.RESUMEN. Con base en entrevistas y observaciones de campo, presentamos información sobre individuos de la guacamaya verde (Ara militaris) en la comunidad de Caballo Blanco, en el centro occidente de Veracruz. Se obtuvieron observaciones en 2014 y 2015 en un sitio con acantilados cubiertos por relictos de bosques caducifolios. Sin embargo, la población local dijo que había visto guacamayas verdes en esta área por lo menos desde 2012. Es importante seguir trabajando con la gente de Caballo Blanco para asegurar la preservación de esta población de guacamayas verdes. Además, es necesario profundizar aspectos de su ecología en este sitio, que sería el único con presencia reciente y constante de esta especie en Veracruz.

    Global consortium for the classification of fungi and fungus-like taxa

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    The Global Consortium for the Classification of Fungi and fungus-like taxa is an international initiative of more than 550 mycologists to develop an electronic structure for the classification of these organisms. The members of the Consortium originate from 55 countries/regions worldwide, from a wide range of disciplines, and include senior, mid-career and early-career mycologists and plant pathologists. The Consortium will publish a biannual update of the Outline of Fungi and fungus like taxa, to act as an international scheme for other scientists. Notes on all newly published taxa at or above the level of species will be prepared and published online on the Outline of Fungi website (https://www.outlineoffungi.org/), and these will be finally published in the biannual edition of the Outline of Fungi and fungus-like taxa. Comments on recent important taxonomic opinions on controversial topics will be included in the biannual outline. For example, ‘to promote a more stable taxonomy in Fusarium given the divergences over its generic delimitation’, or ‘are there too many genera in the Boletales?’ and even more importantly, ‘what should be done with the tremendously diverse ‘dark fungal taxa?’ There are undeniable differences in mycologists’ perceptions and opinions regarding species classification as well as the establishment of new species. Given the pluralistic nature of fungal taxonomy and its implications for species concepts and the nature of species, this consortium aims to provide a platform to better refine and stabilise fungal classification, taking into consideration views from different parties. In the future, a confidential voting system will be set up to gauge the opinions of all mycologists in the Consortium on important topics. The results of such surveys will be presented to the International Commission on the Taxonomy of Fungi (ICTF) and the Nomenclature Committee for Fungi (NCF) with opinions and percentages of votes for and against. Criticisms based on scientific evidence with regards to nomenclature, classifications, and taxonomic concepts will be welcomed, and any recommendations on specific taxonomic issues will also be encouraged; however, we will encourage professionally and ethically responsible criticisms of others’ work. This biannual ongoing project will provide an outlet for advances in various topics of fungal classification, nomenclature, and taxonomic concepts and lead to a community-agreed classification scheme for the fungi and fungus-like taxa. Interested parties should contact the lead author if they would like to be involved in future outlines

    Ciprofibrate therapy in patients with hypertriglyceridemia and low high density lipoprotein (HDL)-cholesterol: greater reduction of non-HDL cholesterol in subjects with excess body weight (The CIPROAMLAT study)

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    BACKGROUND: Hypertriglyceridemia in combination with low HDL cholesterol levels is a risk factor for cardiovascular disease. Our objective was to evaluate the efficacy of ciprofibrate for the treatment of this form of dyslipidemia and to identify factors associated with better treatment response. METHODS: Multicenter, international, open-label study. Four hundred and thirty seven patients were included. The plasma lipid levels at inclusion were fasting triglyceride concentrations between 1.6–3.9 mM/l and HDL cholesterol ≤ 1.05 mM/l for women and ≤ 0.9 mM/l for men. The LDL cholesterol was below 4.2 mM/l. All patients received ciprofibrate 100 mg/d. Efficacy and safety parameters were assessed at baseline and at the end of the treatment. The primary efficacy parameter of the study was percentage change in triglycerides from baseline. RESULTS: After 4 months, plasma triglyceride concentrations were decreased by 44% (p < 0.001). HDL cholesterol concentrations were increased by 10% (p < 0.001). Non-HDL cholesterol was decreased by 19%. A greater HDL cholesterol response was observed in lean patients (body mass index < 25 kg/m(2)) compared to the rest of the population (8.2 vs 19.7%, p < 0.001). In contrast, cases with excess body weight had a larger decrease in non-HDL cholesterol levels (-20.8 vs -10.8%, p < 0.001). There were no significant complications resulting from treatment with ciprofibrate. CONCLUSIONS: Ciprofibrate is efficacious for the correction of hypertriglyceridemia / low HDL cholesterol. A greater decrease in non-HDL cholesterol was found among cases with excess body weight. The mechanism of action of ciprofibrate may be influenced by the pathophysiology of the disorder being treated

    Quid: observatorio de medios

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    El informe está dividido en cuatro apartados: “Derecho a la información y transparencia”, “La televisión mexicana”, “Empresas y prácticas periodísticas” y “Los que se fueron”. En el primero de ellos se presenta un texto que ayuda a entender cuál es el momento en el que se encuentran las propuestas legislativas para regular a los medios y las telecomunicaciones en México, y una evaluación de los primeros cinco años del Instituto de Transparencia e Información Pública de Jalisco. El segundo apartado del informe es ecléctico, pues se compone de artículos que trabajan distintas temáticas de la televisión:la estructura y oferta de la televisión en nuestro país (en particular en la ciudad de Guadalajara), la televisión por cable (enfatizando el caso de Megacable), un recuento de cómo se gestó el Canal 44 y de sus prospectivas en 2011, y los mundiales de futbol. La tercera parte del informe documenta algunas de las situaciones más importantes que se viven en el periodismo local: estos trabajos presentan sistemas en crisis (alta vulnerabilidad de los periodistas mexicanos ante un clima de violencia que lejos de disminuir va en aumento, y la participación, por acción u omisión, del Estado mexicano en la sistemática violación de los derechos de quienes dedican su vida al trabajo periodístico. Los siguientes artículos tratan sobre las transformaciones de las empresas periodísticas, particularmente las del sector de la prensa escrita: la rápida e inexorable desaparición de los suplementos culturales, y una radiografía sobre las formas de producción de algunas secciones internacionales de los periódicos tapatíos. Al final se presentan las semblanzas de José Galindo, Raúl Mora Lomelí, S.J., Tomás Eloy Martínez y Juan Pablo Rosell.ITESO, A.C

    Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology

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    <p>Abstract</p> <p>Background</p> <p>Worldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City.</p> <p>Methods</p> <p>Included in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level).</p> <p>Results</p> <p>Although a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high risk. There was a positive correlation between the average number of persons per household and the incidence of the pre-B immunophenotype (Pearson's r, 0.789; P = 0.02).</p> <p>Conclusions</p> <p>The frequency of ALL in Mexico City is among the highest in the world, similar to those found for Hispanics in the United States and in Costa Rica.</p

    Global transpiration data from sap flow measurements : the SAPFLUXNET database

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    Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.Peer reviewe

    Pervasive gaps in Amazonian ecological research

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