417 research outputs found

    Existence of constant mean curvature graphs in hyperbolic space

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    Morphometry of the epidermis of an invasive megascoelecid earthworm (Amynthas gracilis, Kinberg 1867) inhabiting actively volcanic soils in the Azores archipelago

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    Copyright (c) 2010 Elsevier Inc. All rights reserved.For the first time, the structure, dimensions, and composition of the epidermis of an invasive earthworm species that has successfully colonized hostile conditions in actively volcanic soil on Sao Miguel (Azores) have been measured. Metal concentrations in actively volcanic (Furnas) and volcanically inactive(Fajã) soils were similar; however, Furnas soil was characterised by elevated temperature (10 1C differential), relative hypoxia, extremely high CO2 tension, and accompanying acidity. The epidermis of earthworm’s resident at Fajã was approximately twice the thickness of the epidermis of conspecifics resident in Furnas soil. Reference worms transferred to Furnas soil for 14 days experienced an epidermal thinning of approximately 51%. In comparison, when Furnas earthworms were transferred to mesocosms at the relatively benign Fajã site, their epidermal thickness increased by approximately 21%over 14 days. Earthworms resident in Furnas soil had higher goblet cell counts than the residents of volcanically inactive soil on a neighbouring island (S.Maria). Transferring worms from S.Maria to mesocosmsat Furnas induced a significant increase in goblet cell counts. Clearly, the active volcanic environment at Furnas poses a multifactorial stress challenge to the epigeic A. gracilis colonizer.This study was financially supported by CIRN (University of the Azores), and DRCT(Government of the Azores). Luis Cunha was supported by a Doctoral grant from DRCT (M312/F/029/2007)

    Características clínicas y epidemiológicas de púrpura de Schönlein Henoch en el Hospital Manuel de Jesús Rivera “La Mascota” en el periodo comprendido de enero del 2012 a diciembre del 2016

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    El presente estudio tuvo como objetivo describir las características epidemiológicas, clínicas de los niños diagnosticados con púrpura de Henoch-Schönlein (PHS) hospitalizados en el Hospital Manuel de Jesús Rivera “La Mascota” durante el periodo enero del 2012 a diciembre del 2016. Se trata de un estudio descriptivo, retrospectivo, longitudinal. Se seleccionaron las historias de pacientes entre 1 y 15 años, hospitalizados con diagnóstico de PHS, que cumplieran con los criterios. Se excluía a todo paciente que hubiera presentado patologías previas con vasculitis o durante el curso de su enfermedad. Los datos obtenidos fueron procesados por SPSS versión 15 y Microsoft Office 2013. Entre los resultados encontrados se estudiaron 21 niños, 57% varones y 43% mujeres, el rango de edades fue de 1 a 15 años (media 8 ±1.2), el grupo etario más afectado fue el escolar (47%), seguido de adolescentes (38%) y del preescolar (15%). Se identificó como posible factor desencadenante la infección de vías respiratorias, de los cuales el número de casos de PHS fue mayor en invierno. Se observó compromiso cutáneo (95%), articular por dolor (85%), inflamación de articulaciones (14%) o cierto grado de limitación (285) digestivo (52%) y renal, principalmente edema y proteinuria (23%). El signo de púrpura palpable se encontró en todos los pacientes y los miembros inferiores fueron los más afectados (98%). A nivel gastrointestinal el dolor abdominal fue el signo de mayor presentación (49%), y la afección renal se presentó en un 23.8%, más frecuentemente con proteinuria. Las características clínicas de la PHS fueron por compromiso cutáneo, articular, digestivo y renal. La púrpura palpable fue la manifestación más importante y constituiría el criterio clínico sine qua non para sospechar o establecer el diagnóstico. El pronóstico de la PHS en el presente estudio es aún incierto, ya que no se cuenta con registro de seguimiento suficiente para poder determinarlo

    The speciation of Noctua atlantica (Lepidoptera, Noctuidae) occurred in the Azores as supported by a molecular clock based on mitochondrial COI sequences

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    The complete sequence of the cytochrome c oxidase subunit I (COI) gene of Noctua atlantica (Warren, 1905) has been determined and deposited in the NCBI GenBank under the Accession number AY600452. Complete and partial COI sequences of other Lepidoptera have been collected and used to reconstruct a phylogeny with both the Neighbor-Joining and the Maximum Likelihood methods. A molecular clock calibrated for our models indicate a divergence time between Noctua atlantica and Noctua pronuba of 4.7-5.9 Million years, consistent with the geological age of the Azores and suggesting that the speciation process of N. atlantica occurred in this archipelago

    Mutation patterns of mtDNA: Empirical inferences for the coding region

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    Background: Human mitochondrial DNA (mtDNA) has been extensively used in population and evolutionary genetics studies. Thus, a valid estimate of human mtDNA evolutionary rate is important in many research fields. The small number of estimations performed for the coding region of the molecule, showed important differences between phylogenetic and empirical approaches. We analyzed a portion of the coding region of mtDNA (tRNALeu, ND1 and tRNAIle genes), using individuals belonging to extended families from the Azores Islands (Portugal) with the main aim of providing empirical estimations of the mutation rate of the coding region of mtDNA under different assumptions, and hence to better understand the mtDNA evolutionary process. Results: Heteroplasmy was detected in 6.5% (3/46) of the families analyzed. In all of the families the presence of mtDNA heteroplasmy resulted from three new point mutations, and no cases of insertions or deletions were identified. Major differences were found in the proportion and type of heteroplasmy found in the genes studied when compared to those obtained in a previous report for the D-loop. Our empirical estimation of mtDNA coding region mutation rate, calculated taking into account the sex of individuals carrying new mutations, the probability of intra-individual fixation of mutations present in heteroplasmy and, to the possible extent, the effect of selection, is similar to that obtained using phylogenetic approaches. Conclusion: Based on our results, the discrepancy previously reported between the human mtDNA coding region mutation rates observed along evolutionary timescales and estimations obtained using family pedigrees can be resolved when correcting for the previously cited factors

    Bioactive compounds, antioxidant and antimicrobial activity of propolis extracts during In vitro digestion

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    The objective of this research was to determine the content of total phenols, total flavonoids, and the antioxidant and antimicrobial activity of the ethanolic extracts of propolis obtained by two methodologies during in vitro digestion. Ethanolic extracts of propolis were obtained by ultrasound and maceration and the yield and content of the bioactive compounds, as well as their antimicrobial and antioxidant activity, were evaluated. Yields higher than those reported in other investigations (71.6%) were obtained. The highest content of phenols and flavonoids in the ethanolic extracts was 34,406.6 mg GAE/100 g in propolis from San Pedro, obtained by maceration (SP M), and 19,523.2 mg QE/100 g in propolis from Teotitlán, obtained by ultrasound (TU), respectively, being higher than what is established in Mexican regulations. The antioxidant and antimicrobial activity of the extracts was not affected by the method of obtaining. At the end of the in vitro digestion there was an 80% loss of the phenolic content and a 90% loss of the flavonoid content. Therefore, antioxidant activity was affected. On the other hand, ultrasound improves the obtaining of bioactive compounds. In vitro digestion decreases the content of bioactive compounds; therefore, their functional properties are affected. Thus, it is important to consider technologies that allow extracts to be protected from in vitro digestion conditions.info:eu-repo/semantics/publishedVersio

    Genetic Evidence Supports the Multiethnic Character of Teopancazco, a Neighborhood Center of Teotihuacan, Mexico (AD 200-600)

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    Multiethnicity in Teopancazco, Teotihuacan, is supported by foreign individuals found in the neighborhood center as well as by the diversity observed in funerary rituals at the site. Studies of both stable and strontium isotopes as well as paleodietary analysis, suggest that the population of Teopancazco was composed by three population groups: people from Teotihuacan, people from nearby sites (Tlaxcala-Hidalgo-Puebla), and people from afar, including the coastal plains. In an attempt to understand the genetic dynamics in Teopancazco we conducted an ancient DNA (aDNA) analysis based on mtDNA. Our results show that the level of genetic diversity is consistent with the multiethnicity phenomenon at the neighborhood center. Levels of genetic diversity at different time periods of Teopancazco's history show that multiethnicity was evident since the beginning and lasted until the collapse of the neighborhood center. However, a PCA and a Neighbor-Joining tree suggested the presence of a genetically differentiated group (buried at the Transitional phase) compared to the population from the initial phase (Tlamimilolpa) as well as the population from the final phase (Xolalpan) of the history of Teopancazco. Genetic studies showed no differences in genetic diversity between males and females in the adult population of Teopancazco, this data along with ample archaeological evidence, suggest a neolocal post-marital pattern of residence in Teopancazco. Nevertheless, genetic analyses on the infant population showed that the males are significantly more heterogeneous than the females suggesting a possible differential role in cultural practices by sex in the infant sector. Regarding interpopulation analysis, we found similar indices of genetic diversity between Teopancazco and heterogeneous native groups, which support the multiethnic character of Teopancazco. Finally, our data showed a close genetic relationship between Teopancazco and populations from the "Teotihuacan corridor" and from Oaxaca and the Maya region, in agreement with previous archaeological evidence

    Efecto de Xoconostle (Opuntia matudae Scheinvar) sobre la concentración de metano y las variables ruminales durante una fermentación in vitro de rastrojo de maíz

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    The effect of the addition of xoconostle on in vitro ruminal fermentation of corn stover was determined in order to reduce methane emission. Previous studies have shown that xoconostle contains bioactive compounds with potential antimicrobial activity that enhance ruminal fermentation. Zero point zero percent, 2.0 %, 4.0 % and 6.0 % of xoconostle were added. The following were determined: chemical composition of the substrates, phenolic compounds, antioxidant capacity, in vitro disappearance of dry matter (IVDDM), the production of volatile fatty acids (VFAs) and the kinetic variables of gas production. The volume of methane was measured using the technique of capturing carbon dioxide in sodium hydroxide solution. The content of protein, ether extract, total phenols and antioxidant activity significantly increased (P<0.05) with the addition of xoconostle. The IVDDM also increased with the addition of xoconostle. Regarding the production of propionic acid, it increased significantly (P<0.05) with 6.0 % of xoconostle. The kinetic parameters obtained by the best fit of the experimental data showed a higher digestion rate and lower methane production with the addition of 4.0 and 6.0 % of xoconostle. The use of xoconostle as an additive in ruminant diets decreases methane production in vitro so it can be an alternative to mitigate the increase in the greenhouse effect and benefit the cultivation of a commercially not very appreciated fruit.Se determinó el efecto de la adición de xoconostle en la fermentación ruminal in vitro de rastrojo de maíz con objeto de reducir la emisión de metano. Estudios previos han demostrado que el xoconostle contiene compuestos bioactivos con actividad antimicrobiana potencial que mejoran la fermentación ruminal. Se adicionaron el 0.0%, 2.0%, 4.0% y 6.0% de xoconostle. Se determinó la composición química de los sustratos, compuestos fenólicos, capacidad antioxidante, desaparición in vitro de la materia seca (DIVMS), la producción de ácidos grasos volátiles (AGV) y las variables de cinética de producción de gas. El volumen de metano se midió utilizando la técnica de captura de bióxido de carbono en solución de hidróxido de sodio. Con la adición del xoconostle se incrementó significativamente (P<0.05) el contenido de proteína, extracto etéreo, fenoles totales y actividad antioxidante. La DIVMS también se incrementó con la adición del xoconostle. Respecto a la producción de ácido propiónico, ésta se incrementó significativamente (P<0.05) con el 6.0 % de xoconostle. Los parámetros cinéticos obtenidos mediante el mejor ajuste de los datos experimentales mostraron una mayor tasa de digestión y menor producción de metano con la adición del 4.0 y 6.0 % de xoconostle. El uso de xoconostle como aditivo en dietas para rumiantes disminuye la producción de metano in vitro por lo que puede ser una alternativa para mitigar el incremento del efecto invernadero y beneficiar el cultivo de un fruto comercialmente no muy apreciado.
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