1,486 research outputs found

    A Lagrangian Analysis of Cold Cloud Clusters and Their Life Cycles With Satellite Observations

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    Cloud movement and evolution signify the complex water and energy transport in the atmosphere-ocean-land system. Detecting, clustering, and tracking clouds as semi coherent cluster objects enables study of their evolution which can complement climate model simulations and enhance satellite retrieval algorithms, where there are large gaps between overpasses. Using an area-overlap cluster tracking algorithm, in this study we examine the trajectories, horizontal extent, and brightness temperature variations of millions of individual cloud clusters over their lifespan, from infrared satellite observations at 30-minute, 4-km resolution, for a period of 11 years. We found that the majority of cold clouds were both small and short-lived and that their frequency and location are influenced by El Nino. More importantly, this large sample of individually tracked clouds shows their horizontal size and temperature evolution. Longer lived clusters tended to achieve their temperature and size maturity milestones at different times, while these stages often occurred simultaneously in shorter lived clusters. On average, clusters with this lag also exhibited a greater rainfall contribution than those where minimum temperature and maximum size stages occurred simultaneously. Furthermore, by examining the diurnal cycle of cluster development over Africa and the Indian subcontinent, we observed differences in the local timing of the maximum occurrence at different life cycle stages. Over land there was a strong diurnal peak in the afternoon while over the ocean there was a semi-diurnal peak composed of longer-lived clusters in the early morning hours and shorter-lived clusters in the afternoon. Building on regional specific work, this study provides a long-term, high-resolution, and global survey of object-based cloud characteristics

    Native CuA Redox Sites are Largely Resilient to pH Variations within Physiological Range

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    Previous studies on engineered CuA centres have shown that one of the histidine ligands is protonated and dissociated from the metal site at physiological pH values, thus suggesting a role in regulating proton-coupled electron transfer of cytochrome c oxidases in vivo. Here we report that for native CuA such protonation does not take place at physiologically relevant pH values and, furthermore, no significant changes in the spectroscopic and redox properties of the metal site occur at low pH.Fil: Álvarez Paggi, Damián Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; ArgentinaFil: Abriata, Luciano Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Murgida, Daniel Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; ArgentinaFil: Vila, Alejandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Biología Molecular y Celular de Rosario; Argentin

    Climatological Behavior of Precipitating Clouds in the Northeast Region of Brazil

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    This study aims to analyze the climatological classification of precipitating clouds in the Northeast of Brazil using the radar on board the Tropical Rainfall Measuring Mission (TRMM) satellite. Thus, for this research a time series of 15 years of satellite data (period 1998–2012) was analyzed in order to identify what types of clouds produce precipitation estimated by Precipitation Radar (PR) and how often these clouds occur. From the results of this work it was possible to estimate the average relative frequency of each type of cloud present in weather systems that influence the Northeast of Brazil. In general, the stratiform clouds and shallow convective clouds are the most frequent in this region, but the associated rainfall is not as abundant as precipitation caused by deep convective clouds. It is also seen that a strong signal of shallow convective clouds modulates rainfall over the coastal areas of Northeast of Brazil and adjacent ocean. In this scenario, the main objective of this study is to contribute to a better understanding of the patterns of cloud types associated with precipitation and building a climatological analysis from the classification of clouds

    Thermometric data from cultivated valleys in Mendoza and San Juan (Argentina) : temporality problems

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    Habitualmente los registros meteorológicos de Mendoza y San Juan (Argentina) son de corta duración y no contemporáneos, limitando el análisis y la caracterización climática zonal. Para realizar un estudio a agroclimático es necesario contar con información meteorológica completa de muchos sitios dentro de una zona. Objetivo de este trabajo fue la caracterización de ambas provincias. Con los datos disponibles y apoyándose en estaciones de referencia con más de 30 años de registros meteorológicos completos se integraron los datos de estaciones con información parcial. Para ello se aplicó un modelo basado en la correlación entre los datos de las estaciones de referencia y los de las demás. Obtenidos los datos faltantes se elaboró una cartografía de isotermas sobre mapas de Mendoza y San Juan. En todos los casos las correlaciones entre las estaciones tuvieron valores superiores a r = 0.92. La distribución de las isotermas presentó un patrón lógico con respecto a la latitud y al paisaje (altitud). Las temperaturas máximas medias están relacionadas con la altitud, al igual que las mínimas medias, cuando el sitio está por encima de los 900 msnm. Por debajo de esta altura, están más relacionadas con la latitud.The provinces 01 Mendoza and San Juan have in general meteorological data 01 short periods 01 time and not always at the same time. This is a practica llimitation when climatic annalysis and characterization is intendet to be performed. In order to performan agroclimatic study it is necessary to have complete meteorologic information at several mesoclimática sites in the area that is going to be characterized. The goal 01 this work was to perform a mesoclimatic characterization 01 Mendoza and San Juan provinces. In order to this, with the available data and supporting the work on the relerence meteorological stations, the missing data 01 some of the stations was filled. The reference meteorological stations were those that have more than 30 years of complete data. A sim model based on the correlations between the data from the reference stations and the stations with incomplete data was applied. Once the missing data were filled, the isothermals were drawn on Mendoza and San Juan maps. The correlations between stations presented values of r = 0.92 or higher. The isotherms distribution showed a logical paltern according to latitude and landscape (altitude). The maximum average temperatures were related with the altitud as the minimum average temperatures when the site was above 900 over sea level, while below this altitud the lalter ones were more related to the latitud.Fil: Bohigas, Miquel. Universidad de BarcelonaFil: Ortega, Alejandro. Instituto Nacional de Tecnología Agropecuaria (Argentina)Fil: Vila, Hernán. Instituto Nacional de Tecnología Agropecuaria (Argentina)Fil: Caretta, Adriana I.. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Pérez Peña, Jorge. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Fontagnol , Daniel. Instituto Nacional de Tecnología Agropecuaria (Argentina

    Trapping and Characterization of a Reaction Intermediate in Carbapenem Hydrolysis by \u3cem\u3eB. cereus\u3c/em\u3e Metallo-β-lactamase

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    Metallo-β-lactamases hydrolyze most β-lactam antibiotics. The lack of a successful inhibitor for them is related to the previous failure to characterize a reaction intermediate with a clinically useful substrate. Stopped-flow experiments together with rapid freeze−quench EPR and Raman spectroscopies were used to characterize the reaction of Co(II)−BcII with imipenem. These studies show that Co(II)−BcII is able to hydrolyze imipenem in both the mono- and dinuclear forms. In contrast to the situation met for penicillin, the species that accumulates during turnover is an enzyme−intermediate adduct in which the β-lactam bond has already been cleaved. This intermediate is a metal-bound anionic species with a novel resonant structure that is stabilized by the metal ion at the DCH or Zn2 site. This species has been characterized based on its spectroscopic features. This represents a novel, previously unforeseen intermediate that is related to the chemical nature of carbapenems, as confirmed by the finding of a similar intermediate for meropenem. Since carbapenems are the only substrates cleaved by B1, B2, and B3 lactamases, identification of this intermediate could be exploited as a first step toward the design of transition-state-based inhibitors for all three classes of metallo-β-lactamases

    The role of molecular crowding in long-range metalloprotein electron transfer: Dissection into site- and scaffold-specific contributions

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    Here we report the effect of molecular crowding on long-range protein electron transfer (ET) and disentangle the specific responses of the redox site and the protein milieu. To this end, we studied two different one-electron redox proteins that share the cupredoxin fold but differ in the metal center, T1 mononuclear blue copper and binuclear CuA, and generated chimeras with hybrid properties by incorporating different T1 centers within the CuA scaffold or by swapping loops between orthologous proteins from different organisms to perturb the CuA site. The heterogeneous ET kinetics of the different proteins was studied by protein film electrochemistry at variable electronic couplings and in the presence of two different crowding agents. The results reveal a strong frictional control of the ET reactions, which for 10 Å tunnelling distances results in a 90% drop of the ET rate when viscosity is matched to that of the mitochondrial interior (ca. 55 cP) by addition of either crowding agent. The effect is ascribed to the dynamical coupling of the metal site and the milieu, which for T1 is found to be twice stronger than for CuA, and the activation energy of protein-solvent motion that is dictated by the overall scaffold. This work highlights the need of explicitly considering molecular crowding effects in protein ET.Fil: Zitare, Ulises Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Szuster, Jonathan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Scocozza, Magali Franca. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Espinoza Cara, Andrés Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Leguto, Alcides José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Morgada, Marcos Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Vila, Alejandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Murgida, Daniel Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

    Planar Wideband Antenna Designs for Wireless Applications in Portable Devices

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    [EN] This paper summarizes the research that has been developed by the authors for the last six years, concerning the design of planar wideband antennas for portable devices. Basic structures combining electric and magnetic elements are proposed, which lead to antennas with large bandwidth. Thus, by using these basic structures, a polarization diversity antenna, a wideband antenna for DVB-H applications and a wideband MIMO antenna have been proposed for wireless applications in mobile terminals. Prototypes of all the antennas have been fabricated and measured at iTEAM and/or CWC facilities.This work was supported by the Spanish Ministerio de Economía y Competitividad under the projects TEC2010-20841-C04-01 and CSD2008-00068, and by the Finnish Funding Agency for Technology and Innovation (Tekes projects AATE and MIMOTA) and its industrial partners, EB, ETS Lindgren, Nokia Devices Oulu and Pulse Finland Inc. Mr. Sonkki also would like to thank the Nokia Foundation and the Infotech Oulu Doctoral Program for financially supporting his PhD studies.Antonino Daviu, E.; Sonkki, M.; Cabedo Fabrés, M.; Ferrando Bataller, M.; Salonen, ET.; Sánchez Escuderos, D.; Herranz Herruzo, JI.... (2014). Planar Wideband Antenna Designs for Wireless Applications in Portable Devices. Waves. 6:17-28. http://hdl.handle.net/10251/52905S1728

    Respuesta a herbicidas con diferentes modos de acción (HRAC) en poblaciones de Amaranthus hybridus L. de la Argentina

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    Amaranthus hybridus L. (yuyo colorado) es actualmente una de las especies maleza más problemáticas en los sistemas de producción de cultivos primavera estivales. Durante diciembre y febrero (2018-2019) se estudió en la Facultad de Ciencias Agrarias de la UNR y la Facultad de Agronomía de la UBA, la respuesta a distintos herbicidas de 50 poblaciones de A. hybridus. Los individuos de cada una de las poblaciones estudiadas se obtuvieron a partir de semillas cosechadas en lotes de producción de soja de diferentes áreas de producción, durante la campaña 2017-18. Se evaluó la respuesta a 2,4-D (1140 g e.a. ha-1), dicamba (560 g e.a. ha-1), fomesafén (250 g ha-1), topramezone (34 g ha-1) y glifosato (1080 g e.a. ha-1). Los herbicidas se aplicaron en cabina estática con un volumen de 140 l ha-1 y sobre plantas entre 2 a 6 hojas. A los 30 días de aplicados se cuantificó la supervivencia de individuos para cada tratamiento. En el conjunto de las poblaciones 84% y 76% fueron absolutamente susceptibles (supervivencia 0%) a 2,4-D y dicamba, respectivamente. No se identificaron poblaciones absolutamente susceptibles a los otros herbicidas evaluados. El 43%, 72% y 82% de las poblaciones presentaron supervivencia mayor a 60% a fomesafén, topramezone y glifosato, respectivamente. Más del 90% de las poblaciones presentaron elevados valores de supervivencia a glifosato, sin embargo, siguen encontrándose algunas susceptibles. Las diferencias en los valores de supervivencia permiten inferir la existencia de variabilidad genética para estos modos de acción, sobre la que podrían actuar los herbicidas, promoviendo procesos de selección de resistencia. Los resultados obtenidos sugieren la necesidad prioritaria de aplicar otras prácticas de manejo culturales que conserven la utilidad y la eficacia de los diferentes herbicidas, particularmente de los auxínicos.Amaranthus hybridus L. (pigweed) is currently one of the most problematic weed species in spring-summer crop production systems During December and February (2018-19) the response to different herbicides from fifty populations of A. hybridus was studied at the Faculty of Agronomy (UNR) and the Faculty of Agronomy (UBA). Individuals from each of the studied populations were obtai - ned from seeds harvested in soybean fields from different production areas, during the 2017-18 season. The response to 2,4-D (1140 g e. a.ha-1), Dicamba (560 g e.a. ha-1), Fomesafén (250 g ha-1), Topramezone (34 g ha-1) and Glyphosate (1080 g e.a. ha-1) were evaluated. Herbi - cides were applied in a static cabin with volume of 140 l ha-1 and 30 days after application, the survival of individuals was quantified for each treatment. In all the populations, 84% and 76% were absolutely susceptible (survival 0%) to 2,4-D and Dicamba, respectively. There were not totally susceptible populations to the other herbicides evaluated. The 43%, 72% and 82% of the populations presented survival greater than 60% to fomesafén, topramezone and glyphosate, respectively. More than 90% of the populations presented high glyphosate survival values, however some susceptible ones are still found. The differences in survival values allow us to infer the existence of genetic variability for these modes of action, on which herbicides could act, promoting resistance selection processes. The results obtained suggest the priority to apply management practices that preserve the usefulness and efficacy of different herbicides, particularly auxinics.Fil: Scursoni, Julio Alejandro. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Vila Aiub, Martin Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Tuesca, Daniel Horacio. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Balassone, Federico Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Morello, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Medina Herrera, Daniela. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Lescano Martinez, María Cecilia. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Montero Bulacio, Nicolás. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Crespo, Roberto Javier. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Depetris, María Rosa. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

    Genomic heterogeneity underlies multidrug resistance in Pseudomonas aeruginosa: A population-level analysis beyond susceptibility testing.

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    BACKGROUND: Pseudomonas aeruginosa is a persistent and difficult-to-treat pathogen in many patients, especially those with Cystic Fibrosis (CF). Herein, we describe a longitudinal analysis of a series of multidrug resistant (MDR) P. aeruginosa isolates recovered in a 17-month period, from a young female CF patient who underwent double lung transplantation. Our goal was to understand the genetic basis of the observed resistance phenotypes, establish the genomic population diversity, and define the nature of sequence evolution over time. METHODS: Twenty-two sequential P. aeruginosa isolates were obtained within a 17-month period, before and after a double-lung transplant. At the end of the study period, antimicrobial susceptibility testing, whole genome sequencing (WGS), phylogenetic analyses and RNAseq were performed in order to understand the genetic basis of the observed resistance phenotypes, establish the genomic population diversity, and define the nature of sequence changes over time. RESULTS: The majority of isolates were resistant to almost all tested antibiotics. A phylogenetic reconstruction revealed 3 major clades representing a genotypically and phenotypically heterogeneous population. The pattern of mutation accumulation and variation of gene expression suggested that a group of closely related strains was present in the patient prior to transplantation and continued to change throughout the course of treatment. A trend toward accumulation of mutations over time was observed. Different mutations in the DNA mismatch repair gene mutL consistent with a hypermutator phenotype were observed in two clades. RNAseq performed on 12 representative isolates revealed substantial differences in the expression of genes associated with antibiotic resistance and virulence traits. CONCLUSIONS: The overwhelming current practice in the clinical laboratories setting relies on obtaining a pure culture and reporting the antibiogram from a few isolated colonies to inform therapy decisions. Our analyses revealed significant underlying genomic heterogeneity and unpredictable evolutionary patterns that were independent of prior antibiotic treatment, highlighting the need for comprehensive sampling and population-level analysis when gathering microbiological data in the context of CF P. aeruginosa chronic infection. Our findings challenge the applicability of antimicrobial stewardship programs based on single-isolate resistance profiles for the selection of antibiotic regimens in chronic infections such as CF
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