Agencia Nacional de Promocion Cientifica y Tecnologica

Argentina

Agencia Nacional de Promocion Cientifica y Tecnologica

Argentina
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Rodriguez Iglesias R.M.,National University of the South | Rodriguez Iglesias R.M.,CONICET | Ciccioli N.H.,National University of the South | Ferreria J.,Agencia Nacional de Promocion Cientifica y Tecnologica | And 4 more authors.
Animal Reproduction Science | Year: 2013

When induced to ovulate during anoestrus, ewes, does and cows frequently develop a short-lived corpora lutea (SLCL) syndrome associated to lack of previous progesterone. Exogenous progesterone precludes SLCL by blocking oxytocin endometrial receptors, thus inducing normal life-span CL (NLCL). Paradoxically, circa 50% of unprimed ewes do not develop SLCL. We report results from 3 trials assessing follicular, oestrous, ovulatory, and luteal end-points after 17β-oestradiol or MAP treatments. Oestradiol benzoate (50μg) induced follicular turnover, provoked ovulation in 40% (24/60) of ewes treated (93% of which developed SLCL), but did not affect the incidence of SLCL (26/53) after an allogenic sexual stimulation (ASS) by rams and oestrous ewes. By the onset of the ASS, most NLCL ewes (26/27) had already experienced turnover of their largest follicle, had smaller largest and second largest follicles, and ovulated their largest follicle more frequently than SLCL ewes did. Most SLCL ewes (19/25) did not ovulate their largest follicles, ovulating instead smaller follicles of identical size to those of NLCL ewes. Priming (40mg of MAP for 12 days) was partially effective at preventing SLCL even when terminated 14 days in advance of an ASS, but failed at completely preventing SLCL when terminated 6 or more days in advance. The coupling of a timed acquisition of full steroidogenic capability before ovulation with a system of endometrial oestradiol-progesterone-oxytocin receptors linked in an unstable equilibrium controlling the amplification of the luteolytic feed-forward loop of oxytocin and prostaglandin F2α explains occurrence and relative incidences of both NLCL and SLCL, and links proximate and ultimate causes of the SLCL syndrome. © 2012 Elsevier B.V.


Tramontina D.,Agencia Nacional de Promocion Cientifica y Tecnologica | Tramontina D.,National University of Cuyo | Erhart P.,Lawrence Livermore National Laboratory | Erhart P.,Gothenburg University | And 12 more authors.
High Energy Density Physics | Year: 2014

We present Non-Equilibrium Molecular Dynamics (NEMD) simulations of shock wave compression along the [001] direction in monocrystalline Tantalum, including pre-existing defects which act as dislocation sources. We use a new Embedded Atom Model (EAM) potential and study the nucleation and evolution of dislocations as a function of shock pressure and loading rise time. We find that the flow stress and dislocation density behind the shock front depend on strain rate. We find excellent agreement with recent experimental results on strength and recovered microstructure, which goes from dislocations to a mixture of dislocations and twins, to twinning dominated response, as the shock pressure increases. © 2013 Elsevier B.V.


Garrido C.E.,Agencia Nacional de Promocion Cientifica y Tecnologica | Hernandez Pezzani C.,National University of Luján | Pacin A.,Fundacion de Investigaciones Cientificas Teresa Benedicta de la Cruz | Pacin A.,National University of Luján
Food Control | Year: 2012

The natural occurrence of mycotoxins in maize in Argentina, from 1999 to 2010 was analysed. Total aflatoxins, deoxynivalenol and zearalenone, were detected and quantified by TLC. Each aflatoxins and fumonisins was quantified by HPLC. A total of 3246 samples for freshly harvested (1655) and storage (1591) was obtained from different regions, from 1999 to 2010. Except for 2003 year in harvest, and for 2007 in storage, aflatoxins levels were low. Average values of aflatoxin B1 for freshly harvested samples were between 0.38 and 2.54μgkg-1 and for storage samples were between 0.22 and 4.5μgkg-1. The average values and frequency of contamination for zearalenone and deoxynivalenol, were low for all years. The average zearalenone contamination in samples of freshly harvested, showed values from no detected up to 83μgkg-1, and in storage samples, from no detected to 17μgkg-1. The average deoxynivalenol contamination of freshly harvested, showed values from no detected up to 140μgkg-1, and for storage samples showed values from no detected to 14μgkg-1. The percentage of maize samples contaminated by fumonisins was between 90 and 100% for all years studied; the average levels were from 1773 to 9093μgkg-1 for freshly harvested maize and for storage from 2525 to 11,528μgkg-1.Co-occurrence of aflatoxins and fumonisin was the most frequent (8.4%), followed by zearalenone and fumonisins (2%). © 2011 Elsevier Ltd.


Rigacci L.N.,Agencia Nacional de Promocion Cientifica y Tecnologica | Rigacci L.N.,National University of Luján | Giorgi A.D.N.,CONICET | Giorgi A.D.N.,National University of Luján | And 4 more authors.
Environmental Monitoring and Assessment | Year: 2013

The lower portion of the Reconquista River is highly polluted. However, little is known about the state of the high and middle basins. The aims of this work were to assess the water quality on the high and middle Reconquista River basins and to determinate if the presence of a reservoir in the river has a positive effect on the water quality. We conducted a seasonal study between August 2009 and November 2010 at the mouth of La Choza, Durazno, and La Horqueta streams at the Roggero reservoir - which receives the water from the former streams - at the origin of the Reconquista River and 17 km downstream from the reservoir. We measured 25 physical and chemical parameters, including six heavy metal concentrations, and performed a multivariate statistical analysis to summarize the information and allow the interpretation of the whole data set. We found that the Durazno and La Horqueta streams had better water quality than La Choza, and the presence of the reservoir contributed to the improvement of the water quality, allowing oxygenation of the water body and processing of organic matter and ammonia. The water quality of the Reconquista River at its origin is good and similar to the reservoir, but a few kilometers downstream, the water quality declines as a consequence of the presence of industries and human settlements. Therefore, the Roggero reservoir produces a significant improvement of water quality of the river, but the discharge of contaminants downstream quickly reverses this effect. © 2013 Springer Science+Business Media Dordrecht.


Alvarez M.G.,Comision Nacional de la Energia Atomica | Lapitz P.,Agencia Nacional de Promocion Cientifica y Tecnologica | Ruzzante J.,Comision Nacional de la Energia Atomica
Corrosion Science | Year: 2012

This paper presents a comparison between the acoustic emission (AE) signals generated by the transgranular stress corrosion cracking (TGSCC) of Ag-10Au (at.%) single crystals and those originated by the intergranular stress corrosion cracking (IGSCC) of a polycrystalline silver-gold alloy under the same experimental conditions. No significant difference is found between the mean amplitude and rise-time of the AE signals registered during the propagation of TGSCC and those measured for IGSCC propagation. Results also show that the AE signals generated by either TGSCC or IGSCC propagation in three different alloys such as AISI 304 SS, α-brass and Ag-Au alloys show similar AE parameters and similar amplitude distribution. © 2011.


Munitz M.S.,National University of Entre Rios | Garrido C.E.,Agencia Nacional de Promocion Cientifica y Tecnologica | Gonzalez H.H.L.,CONICET | Gonzalez H.H.L.,University of Buenos Aires | And 5 more authors.
International Journal of Fruit Science | Year: 2013

Blueberries cv. Misty (2009) and cvs. Emerald, Jewel, and Misty (2010) were analyzed for mycoflora occurrence in the main production area of Argentina. Isolation frequencies and relative densities of the fungal species were statistically compared. Alternaria tenuissima was predominant and the potential presence of Alternaria toxins may pose a risk for blueberries consumption. This is the first report of Aspergillus flavus, Alternaria alternata, Alternaria vaccinii, Arthrinium phaeospermum, Cladosporium cladosporioides, Curvularia lunata, Epicoccum nigrum, Eurotium chevalieri, Fusarium graminearum, Fusarium semitectum, Fusarium verticillioides, Geotrichum candidum, Mucor racemosus, Penicillium citrinum, Trichoderma harzianum and Trichocladium spp. isolated from blueberries in Argentina. © 2013 Copyright Taylor & Francis Group, LLC.


Tramontina D.,Agencia Nacional de Promocion Cientifica y Tecnologica | Tramontina D.,National University of Cuyo | Tramontina D.,University of Mendoza | Ruestes C.,Agencia Nacional de Promocion Cientifica y Tecnologica | And 4 more authors.
Computational Materials Science | Year: 2014

Defective Tantalum monocrystals are expected to display a particularly rich behavior when stressed along different directions. Using molecular dynamics simulations, we model Ta monocrystals containing a single spherical void of different sizes, under uniaxial compression, for two empirical potentials. Differences on the yield point, dislocation generation and plastic heating are observed depending on the void size and stress direction, as distinct slip systems are activated, resulting in a variety of dislocation structures and mobilities. © 2014 Elsevier B.V. All rights reserved.


The aim of this paper is to evaluate the effects of the anthropogenic modifications on the aquifer recharge in coastal dunes zones. The study area is San Clemente del Tuyú, at the marine littoral of the province of Buenos Aires, where the land use has generated significant modifications in the hydrological cycle. Three areas with different types of land use were defined, isophreatic maps were elaborated for the years 1976, 1987, 2006 and the groundwater volume for each survey was estimated. This information was integrated to a Geographic Information System (GIS). The obtained results show that there is a direct relationship between land use evolution and the amount of groundwater stored. The dune zone has reduced its areal distribution in detriment of urbanized areas, that behavior is related to the decrease of fresh water volumes stored in that area. In conclusion, the modifications in land use through the time are reflecting in the phreatic aquifer behavior. Recent detail studies demonstrate that the urbanization brings about the decrease of the water excesses infiltration possibilities, restricting the aquifer natural recharge areas and consequently, the available fresh water reserves. Therefore, for sustainable groundwater management it is necessary to develop a rational plan for land use by preservation of sectors without urbanization or establishing protected areas to facilitate the aquifer recharge.

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