78 research outputs found

    Síntesis y estudio de las propiedades estructurales de zeolitas crecidas a partir del sistema NaOH+H2O+A* (A*= SiO2, Al) en un medio alcalino (pH > 10)

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    In this paper we present the synthesis of Zeolitesthrough the obtaining of a gel composed forthe mixture of alkaline and aluminosilicate solutes.We studied the kinetics of the structurationof zeolites taking into account the reactions A:NaOH+H2O+SiO2 and B: NaOH+H2O+Al. Thevalues of concentration used on each one of thesesolutes were 4.2 g (NaOH), 60- 20 ml (H2O forthe solutes A and B respectively), 6.0 g (SiO2) y 1,7(Al). For the resulting gel, which was gotten whenadding in a slowly way the solute B to the A one, weobtained a Ph equals 14. The synthesized zeoliteswere under thermic treatments of 120°C per cyclesfrom 8 to 10 hours. The structural properties withthe identification of the growing phases were studiedthrough the technic of X- ray diffraction changing2q in the interval 5-60°. From the spectrums ofXRD we observed a mainly predominance of thecrystal phase in the composition of Zeolita with anamorphous component. The presence of phasescoming from other minerals which have been theproducts of the reaction is reflected in the synthesisof the samples. We studied the morphology ofthe surface through scanning electron microscopy(SEM). Based on SEM images it is seen that someareas of the surface are led by isolated grains andcharacterized for values in the size of the grain atabout 20 mm.En este trabajo se presenta la síntesis de zeolitasmediante la obtención de un gel compuesto por lamezcla de soluciones alcalinas y aluminosilicatos.La cinética de formación de las zeolitas se estudióa partir de las reacciones A: NaOH+H2O+SiO2 yB: NaOH+H2O+Al. Los valores de concentraciónempleados en cada una de las soluciones fueron 4.2g (NaOH), 60-20 ml (H2O para las soluciones A yB respectivamente), 6.0 g (SiO2) y 1,7 (Al). Para elgel resultante de la zeolita obtenido al añadir lentamentela disolución B a la A se obtuvo un pH=14.Las zeolitas sintetizadas fueron sometidas a tratamientostérmicos de 120 ºC por ciclos de 8 a 10horas. Las propiedades estructurales junto con laidentificación de las fases de crecimiento fueron estudiadasmediante la técnica de difracción de rayosX (XRD), variando 2q en el rango entre 5-60º. Apartir de los espectros de XRD se observa un predominiode la fase cristalina en la composición dela zeolita acompañado de una componente amorfa.La presencia de fases de otros minerales, productosde la reacción, es evidenciada en el crecimientode las muestras. La morfología de la superficie fueestudiada por microscopia electrónica de barrido(SEM). A partir de las imágenes de SEM se observaque algunas regiones de la superficie son gobernadaspor granos aislados caracterizadas por valoresen el tamaño de grano alrededor de 20 nm

    Multimodal Stimulation of Colorado Potato Beetle Reveals Modulation of Pheromone Response by Yellow Light

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    Orientation of insects to host plants and conspecifics is the result of detection and integration of chemical and physical cues present in the environment. Sensory organs have evolved to be sensitive to important signals, providing neural input for higher order multimodal processing and behavioral output. Here we report experiments to determine decisions made by Colorado potato beetle (CPB), Leptinotarsa decemlineata, in response to isolated stimuli and multimodal combinations of signals on a locomotion compensator. Our results show that in complete darkness and in the absence of other stimuli, pheromonal stimulation increases attraction behavior of CPB as measured in oriented displacement and walking speed. However, orientation to the pheromone is abolished when presented with the alternative stimulation of a low intensity yellow light in a dark environment. The ability of the pheromone to stimulate these diurnal beetles in the dark in the absence of other stimuli is an unexpected but interesting observation. The predominance of the phototactic response over that to pheromone when low intensity lights were offered as choices seems to confirm the diurnal nature of the insect. The biological significance of the response to pheromone in the dark is unclear. The phototactic response will play a key role in elucidating multimodal stimulation in the host-finding process of CPB, and perhaps other insects. Such information might be exploited in the design of applications to attract and trap CPB for survey or control purposes and other insect pests using similar orientation mechanisms

    Timed daily exercise remodels circadian rhythms in mice

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    Regular exercise is important for physical and mental health. An underexplored and intriguing property of exercise is its actions on the body’s 24 h or circadian rhythms. Molecular clock cells in the brain’s suprachiasmatic nuclei (SCN) use electrical and chemical signals to orchestrate their activity and convey time of day information to the rest of the brain and body. To date, the long-lasting effects of regular physical exercise on SCN clock cell coordination and communication remain unresolved. Utilizing mouse models in which SCN intercellular neuropeptide signaling is impaired as well as those with intact SCN neurochemical signaling, we examined how daily scheduled voluntary exercise (SVE) influenced behavioral rhythms and SCN molecular and neuronal activities. We show that in mice with disrupted neuropeptide signaling, SVE promotes SCN clock cell synchrony and robust 24 h rhythms in behavior. Interestingly, in both intact and neuropeptide signaling deficient animals, SVE reduces SCN neural activity and alters GABAergic signaling. These findings illustrate the potential utility of regular exercise as a long-lasting and effective non-invasive intervention in the elderly or mentally ill where circadian rhythms can be blunted and poorly aligned to the external world

    DEXi-Dairy: an ex post multicriteria tool to assess the sustainability of dairy production systems in various European regions

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    Growing awareness of global challenges and increasing pressures on the farming sector, including the urgent requirement to rapidly cut greenhouse gases (GHG) emissions, emphasize the need for sustainable production, which is particularly relevant for dairy production systems. Comparing dairy production systems across the three sustainability dimensions is a considerable challenge, notably due to the heterogeneity of production conditions in Europe. To overcome this, we developed an ex post multicriteria assessment tool that adopts a holistic approach across the three sustainability dimensions. This tool is based on the DEXi framework, which associates a hierarchical decision model with an expert perspective and follows a tree shaped structure; thus, we called it the DEXi-Dairy tool. For each dimension of sustainability, qualitative attributes were defined and organized in themes, sub-themes, and indicators. Their choice was guided by three objectives: (i) better describe main challenges faced by European dairy production systems, (ii) point out synergies and trade-offs across sustainability dimensions, and (iii) contribute to the identification of GHG mitigation strategies at the farm level. Qualitative scales for each theme, sub-theme, and indicator were defined together with weighting factors used to aggregate each level of the tree. Based on selected indicators, a list of farm data requirements was developed to populate the sustainability tree. The model was then tested on seven case study farms distributed across Europe. DEXi-Dairy presents a qualitative method that allows for the comparison of different inputs and the evaluation of the three sustainability dimensions in an integrated manner. By assessing synergies and trade-offs across sustainability dimensions, DEXi-Dairy is able to reflect the heterogeneity of dairy production systems. Results indicate that, while trade-offs occasionally exist among respective selected sub-themes, certain farming systems tend to achieve a higher sustainability score than others and hence could serve as benchmarks for further analyses

    Resultados clínicos en receptores de trasplante renal posterior a la conversión a ImTOR

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    Introducción: los ImTOR, sirolimus y everolimus son una alternativa de inmunosupresión en personas que han recibido transplantes rena-les. En este artículo, se describe la experiencia de pacientes que han experimentado una conversión a ImTOR, y a los que se les ha hecho un seguimiento por más de cinco años.Materiales y métodos: se incluyeron pacientes con transplantes renales desde 1995 hasta 2013, quienes tuvieron indicación de suspensión del inhibidor de calcineurina (ICN) después del tercer mes posterior al trasplante. Todos los pacientes fueron sometidos a biopsia renal antes de la administración de ImTOR. Ningún paciente tuvo diagnóstico de nefropatía crónica, IFTA >40 % o proteinuria >350 mg/24h. Se elaboró un análisis descriptivo para todas las variables. Para estudiar la supervivencia del paciente y del injerto, y la incidencia de rechazo agudo, se usó el método de Kaplan-Meier.Resultados: de 1273 trasplantes renales, la conversión de ICN a ImTOR se realizó en 166 casos (13 %). Al 78 % (n=129) se le administró sirolimus. El 13 % de los pacientes perdió la función del injerto y 7 pacientes (4,2 %) fallecieron. En el 37 % de los casos, se retiró el ImTOR. La principal causa de retiro fue el hallazgo de proteinuria patológica. La incidencia de rechazo agudo después del cambio a ImTOR fue de 9,6 %. La supervivencia del injerto tras uno y cinco años fue de 96,6 % y 83,5 %, respectivamente; y la supervivencia del paciente a uno y cinco años fue de 98 % y 97 %, respectivamente.Conclusiones: el uso de inhibidores ImTOR parece ser seguro en este grupo de pacientes trasplantados, pues hubo una baja tasa de rechazo y buena supervivencia del injert

    DarkCideS 1.0, a global database for bats in karsts and caves

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    Tanalgo, Krizler C., Tabora, John Aries G., de Oliveira, Hernani Fernandes Magalhães, Haelewaters, Danny, Beranek, Chad T., Otálora-Ardila, Aída, Bernard, Enrico, Gonçalves, Fernando, Eriksson, Alan, Donnelly, Melissa, González, Joel Monzón, Ramos, Humberto Fernández, Rivas, Alberto Clark, Webala, Paul W., Deleva, Stanimira, Dalhoumi, Ridha, Maula, Jaycelle, Lizarro, Dennis, Aguirre, Luis F., Bouillard, Nils, Quibod, Ma. Niña Regina M., Barros, Jennifer, Turcios-Casco, Manfredo Alejandro, Martínez, Marcio, Ordoñez-Mazier, Diego Iván, Orellana, José Alejandro Soler, Ordoñez-Trejo, Eduardo J., Ordoñez, Danny, Chornelia, Ada, Lu, Jian Mei, Xing, Chen, Baniya, Sanjeev, Muylaert, Renata L., Dias-Silva, Leonardo Henrique, Ruadreo, Nittaya, Hughes, Alice Catherine (2022): DarkCideS 1.0, a global database for bats in karsts and caves. Scientific Data 9 (1): 155, DOI: 10.1038/s41597-022-01234-4, URL: http://dx.doi.org/10.1038/s41597-022-01234-

    A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

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    The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome and are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. The L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest

    Transoceanic Dispersal and Subsequent Diversification on Separate Continents Shaped Diversity of the Xanthoparmelia pulla Group (Ascomycota)

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    In traditional morphology-based concepts many species of lichenized fungi have world-wide distributions. Molecular data have revolutionized the species delimitation in lichens and have demonstrated that we underestimated the diversity of these organisms. The aim of this study is to explore the phylogeography and the evolutionary patterns of the Xanthoparmelia pulla group, a widespread group of one of largest genera of macrolichens. We used a dated phylogeny based on nuITS and nuLSU rDNA sequences and performed an ancestral range reconstruction to understand the processes and explain their current distribution, dating the divergence of the major lineages in the group. An inferred age of radiation of parmelioid lichens and the age of a Parmelia fossil were used as the calibration points for the phylogeny. The results show that many species of the X. pulla group as currently delimited are polyphyletic and five major lineages correlate with their geographical distribution and the biosynthetic pathways of secondary metabolites. South Africa is the area where the X. pulla group radiated during the Miocene times, and currently is the region with the highest genetic, morphological and chemical diversity. From this center of radiation the different lineages migrated by long-distance dispersal to others areas, where secondary radiations developed. The ancestral range reconstruction also detected that a secondary lineage migrated from Australia to South America via long-distance dispersal and subsequent continental radiation
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