National University of Tucumn


National University of Tucumn

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Lomascolo S.B.,CONICET | Monmany A.C.,University of Puerto Rico at San Juan | Monmany A.C.,National University of Tucumn | Malizia A.,National University of Tucumn | Martin T.E.,University of Montana
Wilson Journal of Ornithology | Year: 2010

We studied the consequences of nest-site choice on nesting success under differing disturbance levels for the Rufous-bellied Thrush (Turdus rufiventris). We compared nest-site choice and nest success between a disturbed site and an undisturbed site in a montane subtropical forest in northwestern Argentina. We found no overall difference in daily predation rate (DPR) between the disturbed and undisturbed sites. However, DPR of nests on bromeliads was significantly lower at the microhabitat level than on other types of subtrates at the disturbed site. T. rufiventris used bromeliads for nesting more often than expected by chance at the disturbed site. DPR did not differ between substrates at the undisturbed site and T. rufiventris used all substrates according to their availability. Nests had higher predation at the disturbed site when DPR on non-bromeliad substrates was compared between disturbed and undisturbed sites. Nest fate was independent of nest height. Our results suggest T. rufiventris' flexibility in nest-site choice, as reflected by increased use of the safest sites, i.e., bromeliads, in the disturbed site compared to the undisturbed site, may allow this species to survive in an otherwise much riskier habitat. Our results illustrate how microhabitat-scale effects can mediate landscape scale effects. © 2010 by the Wilson Ornithological Society.

Dantur Juri M.J.,National University of Tucumn | Liria J.,University of Carabobo | Navarro J.C.,Central University of Venezuela | Rodriguez R.,Laboratorio Of Entomologa Medica | Fritz G.N.,Eastern Illinois University
Florida Entomologist | Year: 2011

Anopheles pseudopunctipennis is a New World species extending from about 30°S in central Argentina to about 40°N in the USA. It is considered one of the most important malaria vectors in South America and its implication in malaria transmission varies along its distribution. We evaluated the effect of ecoregion and geographical distances on the traits or morphological characters of An. pseudopunctipennis females from 15 localities in Argentina and Bolivia using cladistic and morphometric analyses. The cladistic analysis (Maximum Parsimony) demonstrated that the effect of ecoregion characterization in distinguishing between Bolivian and Argentinean populations was stronger than the effect of geographical distances. Morphometric analysis (Discriminant analysis) did not reveal a pattern between Bolivian and Argentinean populations based on geographical distances. Ecoregional characterization of An. pseudopunctipennis populations throughout is range, caused us to conclude that studies of morphological traits characteristics are necessary in differentiating between populations. Moreover, molecular studies are required to determine whether geographical distances influence population differentiation in An. pseudopunctipennis from Argentina and Bolivia, in the extreme south of South America. Copyright © 2011 BioOne All rights reserved.

Dantur Juri M.J.,National University of Tucumn | Dantur Juri M.J.,National University of Chilecito | Stein M.,Northeast National University | Rossi G.C.,CONICET | And 3 more authors.
Journal of the American Mosquito Control Association | Year: 2012

Eleven mosquito species, namely Aedes hastatus, Ae. fulvus, Coquillettidia albicosta, Cq. juxtamansonia, Culex aliciae, Cx. delpontei, Cx. oedipus, Cx. pedroi, Mansonia flaveola, Uranotaenia leucoptera, and Wyeomyia oblita, are recorded for the first time from northwestern Argentina. In addition, 3 species, Cx. brethesi, Limatus durhami, and Ur. nataliae, are reported for the first time from Salta Province. These records extend the geographical distribution of these 3 species to Salta Province. This study also extends the geographical distributions of Cq. nigricans, Cx. chidesteri, and Ma. humeralis to Jujuy Province and of Ae. meprai, Ae. milleri, Ae. oligopistus, Cx. brethesi, Cx. fernandezi, and Cx. tatoi to Tucumn Province. © 2012 by The American Mosquito Control Association, Inc.

Borrero-Gonzlez L.J.,University of Sao Paulo | Nunes L.A.O.,University of Sao Paulo | Guimaraes F.E.G.,University of Sao Paulo | Wojcik J.,McMaster University | And 4 more authors.
Journal of Physics Condensed Matter | Year: 2011

Synchrotron x-ray absorption spectroscopy (XAS) and electron spin resonance (ESR) experiments were performed to determine, in combination with Raman spectroscopy and x-ray diffraction (XRD) data from previous reports, the structure and paramagnetic defect status of Si-nanoclusters (ncls) at various intermediate formation stages in Si-rich Si oxide films having different Si concentrations (y=0.360.42 in Si yO 1y), fabricated by electron cyclotron resonance plasma-enhanced chemical vapor deposition and isochronally (2h) annealed at various temperatures (T a=9001100°C) under either Ar or (Ar+5%H 2) atmospheres. The corresponding emission properties were studied by stationary and time dependent photoluminescence (PL) spectroscopy in correlation with the structural and defect properties. To explain the experimental data, we propose crystallization by nucleation within already existing amorphous Si-ncls as the mechanism for the formation of the Si nanocrystals in the oxide matrix. The cluster-size dependent partial crystallization of Si-ncls at intermediate T a can be qualitatively understood in terms of a crystalline coreamorphous shell Si-ncl model. The amorphous shell, which is invisible in most diffraction and electron microscopy experiments, is found to have an important impact on light emission. As the crystalline core grows at the expense of a thinning amorphous shell with increasing T a, the PL undergoes a transition from a regime dominated by disorder-induced effects to a situation where quantum confinement of excitons prevails. © 2011 IOP Publishing Ltd.

Visintin A.M.,National University of Crdoba | Visintin A.M.,National University of La Rioja | Laurito M.,National University of Crdoba | Stein M.,Northeast National University | And 4 more authors.
Journal of the American Mosquito Control Association | Year: 2010

The geographical distribution of Aedes pennai, Anopheles galvaoi, Coquillettidia albicosta, Cq. nigricans, Culex usquatissimus, Cx. apicinus, Cx. chidesteri, Cx. coronator s.l., Cx. interfor, Cx. maxi, Cx. pipiens, Cx. saltanensis, Cx. educator, Cx. serratimarge, Cx. theobaldi, Psorophora cyanescens, Ps. cilipes, Ps. cingulata, Ps. pallescens, Uranotaenia lanei, Ur. nataliae, Wyeomyia diabolica, and Wy. melanocephala is extended, including new records for 6 provinces and 2 new records for the country, increasing the number of species in Argentina from 226 to 228. © 2010 by The American Mosquito Control Association, Inc.

De Moreno De Leblanc A.,CONICET | Perdigon G.,CONICET | Perdigon G.,National University of Tucumn
Proceedings of the Nutrition Society | Year: 2010

Lactic acid bacteria are present in many foods such as yoghurt and are frequently used as probiotics to improve some biological functions of the host. Many researchers have evaluated the effects of yoghurt and lactic acid bacteria against diseases such as cancer and intestinal inflammation. The preventive effect of probiotics on intestinal carcinogenesis may be associated with changes in the intestinal microbiota, suppressing the growth of bacteria that convert procarcinogens into carcinogens. Other mechanisms could be related to the immune response modulation and have been evaluated using milks fermented with lactic acid bacteria in chemically induced colon cancer and hormone-dependent breast cancer models. We demonstrated, using a murine colon cancer model, that yoghurt consumption inhibited tumour growth by decreasing the inflammatory response by increasing IL-10-secreting cells, cellular apoptosis and diminishing procarcinogenic enzymes. Milk fermented with Lactobacillus helveticus R389 delayed breast tumour growth by decreasing IL-6 and increasing IL-10 in serum and in the mammary glands and tumour-infiltrating immune cells. Previous results obtained with yoghurt administration in a colon cancer model led us to analyse its effect on a trinitrobenzenesulfonic acid-induced intestinal inflammation model in mice. Yoghurt was able to attenuate the symptoms of acute inflammation by reducing inflammatory cytokines, and increasing regulatory cytokine IL-10-producing cells, leading to desirable changes of the intestinal microbiota. It was demonstrated, by using murine models, that the consumption of fermented milks can modulate the immune system and can maintain it in a state of surveillance, which could affront different pathologies such as cancer and intestinal inflammation. Copyright © 2010 The Authors.

Caram J.,National University of Tucumn | Sandoval C.,National University of Tucumn | Tirado M.,National University of Tucumn | Comedi D.,National University of Tucumn | And 4 more authors.
Nanotechnology | Year: 2010

GaAs nanowire (NW)-based p-n photovoltaic devices, with two distinct p and n spatial distributions and where Te was the n-dopant, have been studied by impedance spectroscopy in the 103-107Hz frequency range and the - 1.5-1.5V bias range. For a large n-core/p-shell overlap region within NWs in a coaxial geometry, the p-n junction properties (DC rectification and p-n depletion capacitance) are found to prevail. The impedance data at low bias for both NW devices show large frequency dispersions with relaxation frequencies that are compatible with carrier re-emission times from traps due to GaAs surface states. An increasing conductance with increasing frequency for low bias is observed, suggesting hopping transport through localized states. For large bias the conductance increases exponentially with bias and is frequency independent, indicating conduction through extended states in this regime. © 2010 IOP Publishing Ltd.

Veggiani Aybar C.A.,National University of Tucumn | Dantur Juri M.J.,National University of Tucumn | Lizarralde De Grosso M.S.,National University of Tucumn | Spinelli G.R.,Museo de la Plata
Journal of the American Mosquito Control Association | Year: 2011

Culicoides debilipalpis, C. insignis, C. lahillei, and C. venezuelensis are reported for the first time for Bolivia. The geographical distribution of C. paraensis extends to the Tarija Department. © 2011 by The American Mosquito Control Association, Inc.

Zapata C.,National University of Tucumn | Khalid M.,University of Leipzig | Simonelli G.,National University of Tucumn | Villafuerte M.,National University of Tucumn | And 2 more authors.
Applied Physics Letters | Year: 2011

Magnetic field dependent photoresistivity was measured at 280 K in ZnO ferromagnetic films grown on r-plane Al2O3 under a N 2 atmosphere. A correlation between the negative magneto photoresistivity and the existence of defect-induced magnetic order was found. The effect of magnetic field on the transient photoresistivity is to slow down the recombination process enhancing the photocarriers density. The experimental results demonstrate the possibility of tuning photocarriers life time using magnetic field in diluted magnetic semiconductors. © 2011 American Institute of Physics.

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