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An inside look at the sensory biology of triatomines
Barrozo, Romina; Reisenman, Carolina Esther; Guerenstein, Pablo Gustavo; Lazzari, Claudio Ricardo; Lorenzo, Marcelo Gustavo
Although kissing bugs (Triatominae: Reduviidae) are perhaps best known as vectors of Chagas disease, they are important experimental models in studies of insect sensory physiology, pioneered by the seminal studies of Wigglesworth and Gillet more than eighty years ago. Since then, many investigations have revealed that the thermal, hygric, visual and olfactory senses play critical roles in the orientation of these blood-sucking insects towards hosts. Here we review the current knowledge about the role of these sensory systems, focussing on relevant stimuli, sensory structures, receptor physiology and the molecular players involved in the complex and cryptic behavioural repertoire of these nocturnal insects. Odours are particularly relevant, as they are involved in host search and are used for sexual, aggregation and alarm communication. Tastants are critical for a proper recognition of hosts, food and conspecifics. Heat and relative humidity mediate orientation towards hosts and are also important for the selection of resting places. Vision, which mediates negative phototaxis and flight dispersion, is also critical for modulating shelter use and mediating escape responses. The molecular bases underlying the detection of sensory stimuli started to be uncovered by means of functional genetics due to both the recent publication of the genome sequence of Rhodnius prolixus and the availability of modern genome editing techniques.
Adsorption dynamics of molecular nitrogen at an Fe(111) surface
Adsorption dynamics of molecular nitrogen at an Fe(111) surface
Nosir, M. A.; Martin Gondre, L.; Bocan, Gisela Anahí; Díez Muiño, R.
We present an extensive theoretical study of N2 adsorption mechanisms on an Fe(111) surface. We combine the static analysis of a six-dimensional potential energy surface (6D-PES), based on ab initio density functional theory (DFT) calculations for the system, with quasi-classical trajectory (QCT) calculations to simulate the adsorption dynamics. There are four molecular adsorption states, usually called γ, δ, α, and ε, arising from our DFT calculations. We find that N2 adsorption in the γ-state is non-activated, while the threshold energy is associated with the entrance channel for the other three adsorption states. Our QCT calculations confirm that there are activated and nonactivated paths for the adsorption of N2 on the Fe(111) surface, which is in agreement with previous experimental investigations. Molecular dynamics at a surface temperature Ts = 300 K and impact energies Ei in the 0-5 eV range show the relative occupancy of the γ, δ, α, and ε states. The δ-state, however, is only marginally populated despite its adsorption energy being very similar to that of the γ-state. Our QCT calculations trace the dependence of molecular trapping on the surface temperature Ts and initial impact energy Ei and quantify the rates of the different competitive channels that eventually lead to molecular adsorption.
Hydriding kinetics of Mg[sbnd]TiH2 fine dispersions obtained by mechanosynthesis
Hydriding kinetics of Mg[sbnd]TiH2 fine dispersions obtained by mechanosynthesis
Biasetti, Andrés Tobías; Meyer, Marcos; Mendoza Zélis, Luis Alejandro
Mg80[sbnd]Ti20 hydride systems were prepared via reactive ball milling following two different procedures: grinding Mg with Ti or TiH2, in both cases under H2 atmosphere. Such systems were subjected to several cycles of hydrogen uptake and release in volumetric Sieverts apparatus under different pressure and temperature conditions. A structural characterization from SEM images and XRD patterns reveals no essential microstructural differences between the samples obtained by different routes, although a growth in domain size with temperature is observed. Also, the slowing of the kinetics when the temperature goes down is more pronounced in the specimen fabricated by the second route. The influence of the transformed and untransformed phase fractions on the absorption kinetics can be well described using a double Hill function. Such complex function takes into account two distinguishable processes, with and without nucleation, that differentiate themselves as temperature increases. The first one may be related to surface absorption and the second tentatively ascribed to reactions at grain boundaries, dislocations and other extended defects. The fitted values may then be associated to physical constants of the processes occurring during hydrogen absorption in both regions.
Marcadores de formación y resorción ósea y su utilidad para determinar el final del periodo de aposición ósea
Marcadores de formación y resorción ósea y su utilidad para determinar el final del periodo de aposición ósea; Bone formation and resorption markers to evaluate the end of bone apposition
Seijo, Mariana; Oliveri, María Beatriz; Deferrari, Juan Mariano; Casco, Cristina; Zeni, Susana Noemi
El pico de masa ósea (PMO) se alcanza entre los 20 y 35 años, pero la aposición ósea continúa hasta alcanzar el pico de fortaleza ósea (PFO). Se crea así una ventana entre ambos picos que podría ser evaluada mediante marcadores bioquímicos de recambio óseo, ya que durante dicho período la densidad mineral permanece constante. El objetivo fue determinar el final de la aposición ósea mediante marcadores bioquímicos óseos. Se evaluaron por décadas entre 20 y 49 años de edad 139 sujetos sanos de ambos sexos (69 hombres y 70 mujeres), determinando fosfatasa alcalina ósea (FAO), osteocalcina (OC), propéptido amino terminal del colágeno tipo 1 (P1NP) y telopéptido C-terminal del colágeno tipo 1 (CTX). Los marcadores correlacionan negativamente con la edad (OC: r= -0,3; p<0,01; P1NP: r= -0,4; p< 0,01 y CTX: r= -0,4; p< 0,01), exceptuando FAO. En hombres de 20-29 años, P1NP y el CTX fueron significativamente mayores vs. 30-39 años (p<0,05 y p<0,001, respectivamente), y entre 30-39 años vs. de 40-49 años en P1NP y CTX (p<0,05; p<0,001, respectivamente). En mujeres de 20-29 años, P1NP y CTX fueron significativamente mayores vs. 30-39 años (p<0,0001 y p<0,01, respectivamente). Conclusión: los marcadores de remodelado óseo más sensibles y específicos permitirían determinar bioquímicamente el fin de la aposición ósea que se produce entre el PMO y el PFO. Si bien es necesario ampliar el número de sujetos evaluados, los datos que surgen de la presente investigación sentarían las bases para futuros estudios epidemiológicos referidos al fin de la aposición ósea.; Peak bone mass is achieved between 20- 35 years; however bone apposition continues to reach an optimal skeleton strength. The window between peak bone mass and peak bone apposition may be evaluated by biochemical bone turnover markers. The objective of this study was to determine the end of bone apposition through biochemical bone markers in both sexes. A total of 139 subjects (69 men and 70 women) were divided by decades between 20 and 49 years of age. Bone alkaline phosphatase (BAL), osteocalcin (OC), type I collagen propeptide (P1NP) and type I collagen C-terminal telopeptide (CTX) were evaluated. Except BAL, the other bone markers negatively correlated with the age [OC (r= -0.3; p<0.01); P1NP (r= -0.4; p<0.01) and CTX (r= -0.4; p<0.01)]. Regarding men aged 20 to 29 years, P1NP and CTX were significantly higher vs. 30-39 years (p<0.05 y p<0.001, respectively) and. vs. 40-49 years (p<0.05; p<0.001, respectively). In women, the results were similar. Regarding 20-29 years, P1NP and CTX were higher vs. 30-39 years (p<0.001 y p<0.01, respectively). Bone remodeling rate decreases after the third decade, suggesting the end of the apposition period of peak bone mass. Conclusion: The most specific and sensitive bone markers would biochemically determine the end of bone apposition that extends between the peak of bone mass and the peak of bone strength. Although it is necessary to increase the number of subjects evaluated, the data that emerge from the present study would establish the bases for future epidemiological studies referring to the end of bone apposition.
Conformational diversity analysis reveals three functional mechanisms in proteins
Conformational diversity analysis reveals three functional mechanisms in proteins
Monzón, Alexander; Zea, Diego Javier; Fornasari, Maria Silvina; Saldaño, Tadeo Enrique; Fernández Alberti, Sebastián; Tosatto, Silvio C. E.; Parisi, Gustavo Daniel
Protein motions are a key feature to understand biological function. Recently, a large-scale analysis of protein conformational diversity showed a positively skewed distribution with a peak at 0.5 Å C-alpha root-mean-square-deviation (RMSD). To understand this distribution in terms of structure-function relationships, we studied a well curated and large dataset of ~5,000 proteins with experimentally determined conformational diversity. We searched for global behaviour patterns studying how structure-based features change among the available conformer population for each protein. This procedure allowed us to describe the RMSD distribution in terms of three main protein classes sharing given properties. The largest of these protein subsets (~60%), which we call "rigid" (average RMSD = 0.83 Å), has no disordered regions, shows low conformational diversity, the largest tunnels and smaller and buried cavities. The two additional subsets contain disordered regions, but with differential sequence composition and behaviour. Partially disordered proteins have on average 67% of their conformers with disordered regions, average RMSD = 1.1 Å, the highest number of hinges and the longest disordered regions. In contrast, malleable proteins have on average only 25% of disordered conformers and average RMSD = 1.3 Å, flexible cavities affected in size by the presence of disordered regions and show the highest diversity of cognate ligands. Proteins in each set are mostly non-homologous to each other, share no given fold class, nor functional similarity but do share features derived from their conformer population. These shared features could represent conformational mechanisms related with biological functions.
Optimum PR Control applied to LCL filters with Low Resonance Frequency
Optimum PR Control applied to LCL filters with Low Resonance Frequency
Fantino, Roberto Armin; Busada, Claudio; Solsona, Jorge Alberto
A control strategy for LCL Grid-connected voltage source inverters is proposed. Using the injected grid current measurement exclusively, the proposal allows the use of the proportional plus resonant regulator (PR) optimum design, regardless of the filter resonance frequency. Simulation and experimental results that demonstrate the validity and effectiveness of the proposal for different LCL filter resonance frequency values are presented. Also its superiority compared to a control methodrecently proposed in the literature is shown.
ANR INT 3500 - Proceso de evaluación
El Fondo Tecnológico Argentino (FONTAR) anuncia los resultados del proceso de evaluación para la ventanilla ANR INT 3500 mediante Resolución de Directorio N° 028/17.
ANR 2200 2015 C2 - Proceso de evaluación
El Fondo Tecnológico Argentino (FONTAR) anuncia los resultados del proceso de evaluación para la convocatoria ANR 2200 2015 C2 mediante Resolución de Directorio N° 031/17.
ANR 1700 2015 C1 - Proceso de reconsideración
El Fondo Tecnológico Argentino (FONTAR) anuncia los resultados del proceso de reconsideración para la convocatoria ANR 1700 2015 C1 mediante Resolución de Directorio N° 032/17.
ANR 3500 2016 C1 - Proceso de evaluación
El Fondo Tecnológico Argentino (FONTAR) anuncia los resultados del proceso de evaluación para la convocatoria ANR 3500 2016 C1 mediante Resolución de Directorio N° 035/17.
NiNbO Catalyst Deposited on Anodized Aluminum Monoliths for the Oxidative Dehydrogenation of Ethane
NiNbO Catalyst Deposited on Anodized Aluminum Monoliths for the Oxidative Dehydrogenation of Ethane
Santander, José Anibal; Boldrini, Diego Emmanuel; Pedernera, Marisa Noemi; Tonetto, Gabriela Marta
Aluminum monoliths were used as substrates to prepare structured catalysts. A rough alumina layer was generated on the surface of the substrates by anodizing followed by hydrothermal treatments. The dip-coating technique was used for coating the monolithic substrates. Aqueous suspensions with 0.15 and 0.30 g/g of Ni-Nb mixed oxides catalysts were prepared for that purpose. Colloidal SiO2 was added as a binder in order to obtain homogeneous and adherent coatings. The samples were characterized by SEM, TPR, XPS, XRD, and N2 adsorption and tested in the oxidative dehydrogenation (ODH) of ethane to ethylene. The silica particles produced a drop in catalytic activity without affecting ethylene selectivity. The former effect was attributed mainly to a decrease in surface nickel concentration and an increase in reduction temperature. The presence of anodized aluminum substrates in the reaction environment did not have a significant influence on catalytic activity and product distribution, as observed for the coated monoliths used in this work, thus being a useful material to prepare structured catalysts for low-temperature ethane ODH.
ANR 3500 2016 C1 - Proceso de evaluación
El Fondo Tecnológico Argentino (FONTAR) anuncia los resultados del proceso de evaluación para la convocatoria ANR 3500 2016 C1 mediante Resolución de Directorio N°551/16.
Bono para becas PID y PICT
Se comunica que, a través de la Resolución RESOL-2017-21-APN-DANPCYT#MCT, se ha otorgado una bonificación extraordinaria a las Becas PID y PICT financiadas por la Agencia Nacional de Promoción Científica y Tecnológica.
ANR FONSOFT 2015 C1 - Proceso de reconsideración
El Fondo Fiduciario de Promoción de la Industria del Software (FONSOFT) anuncia los resultados del proceso de reconsideración para la convocatoria ANR FONSOFT 2015 C1 mediante Resolución de Directorio N°621/16.
ANR FONSOFT I+D 2014 - Proceso de evaluación
El Fondo Fiduciario de Promoción de la Industria del Software (FONSOFT) anuncia los resultados del proceso de evaluación para la ventanilla ANR FONSOFT I+D 2014 mediante Resolución de Directorio N°617/16.
Emprendedores FONSOFT 2015 C2 - Proceso de evaluación y reconsideración
El Fondo Fiduciario de Promoción de la Industria del Software (FONSOFT) anuncia los resultados del proceso de evaluación y reconsideración para la convocatoria Emprendedores FONSOFT 2015 C2 mediante Resolución de Directorio N°616 y 622/16.
Informes Técnicos - Actualización
Se recuerda a los responsables de los proyectos adjudicados y que actualmente se encuentran en ejecución, que es requisito presentar un informe técnico por cada año transcurrido desde la fecha de inicio del proyecto.
Nest niche overlap among the endangered Vinaceous-breasted Parrot (Amazona vinacea) and sympatric cavity-using birds, mammals, and social insects in the subtropical Atlantic Forest, Argentina
Nest niche overlap among the endangered Vinaceous-breasted Parrot (Amazona vinacea) and sympatric cavity-using birds, mammals, and social insects in the subtropical Atlantic Forest, Argentina
Bonaparte, Eugenia Bianca; Cockle, Kristina Louise
Many forest bird species require tree cavities for nesting, and share this resource with a diverse community of animals. When cavities are limited, niche overlap can result in interspecific competition, with negative consequences for threatened populations. Vinaceous-breasted Parrots (Amazona vinacea) are endangered cavity nesters endemic to the subtropical Atlantic Forest, where cavities are scarce. We examined nest niche overlap among Vinaceous-breasted Parrots and 9 potential competitors (birds and mammals >140 g, and social insects) in Argentina, considering (1) timing of breeding, (2) characteristics of cavities (depth, entrance diameter, height), trees (diameter at breast height DBH, species, condition), and habitat (surrounding land use, distance to edge), and (3) interspecific cavity reuse. During 10 breeding seasons we studied nests and roosts, measured their characteristics, and monitored cavities to detect reuse. We used multinomial logistic regression to determine whether the 6 most abundant taxa differed in nest and roost site characteristics. Timing of breeding overlapped for all bird species except the White-eyed Parakeet (Psittacara leucophthalmus). No combination of cavity, tree, and habitat characteristics predicted the taxa that utilized cavities. Moreover, 8 of the 10 taxa reused cavities interspecifically. The high level of overlap in realized nest niche, combined with previous evidence that cavities could limit bird density in our study area, suggest the possibility of interspecific competition for cavities among multiple taxa. Although models did not perform well at classifying cavities by taxon, some characteristics of cavities, trees, and habitat were selected more by Vinaceous-breasted Parrots than by other taxa, and we recommend targeting conservation efforts toward cavities and trees with these characteristics (7-40 cm entrance diameter, >10 m high, DBH >55 cm). We found 62% of Vinaceous-breasted Parrot nests on farms (vs. ≤50% for other taxa), highlighting the importance of working with local farmers to conserve cavities in anthropogenic habitats as well as in protected areas.
FONREBIO - Manual de Operación
Se informa que se encuentran disponibles los Manuales de Operaciones de FONREBIO para Empresas Privadas e Instituciones Públicas.
PICT 2016 CABBIO - Proceso de adjudicación
El Fondo para la Investigación Científica y Tecnológica (FONCyT) anuncia los resultados del proceso de adjudicación de la convocatoria PICT 2016 Categoría Internacional "CABBIO" mediante la Resolución N° 012/17 del Directorio de la Agencia con fecha 10/01/17.
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