Buenos Aires, Argentina

National University of Lomas de Zamora

Buenos Aires, Argentina

The National University of Lomas de Zamora is an Argentine state national university located in Lomas de Zamora, Buenos Aires Province. Maintaining extensive research facilities, and with over 30,000 students, UNLZ is one of the most important universities of the Greater Buenos Aires area.The university includes five departments: Agronomy, Economics, Engineering, Law, and Social science. The Media Department, part of the School of Social science, publishes InfoRegión, an online periodical covering the Greater Buenos Aires area. Wikipedia.

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Rivera O.E.,National University of Lomas de Zamora | Varayoud J.,National University of Santa | Rodriguez H.A.,National University of Santa | Munoz-de-Toro M.,National University of Santa | Luque E.H.,National University of Santa
Reproductive Toxicology | Year: 2011

We hypothesized that neonatal xenoestrogen exposure affects the ovarian follicular dynamics in lambs. Female lambs were exposed from postnatal day (PND) 1-14 to low doses of diethylstilbestrol (DES) or bisphenol A (BPA). At PND 30, the follicular dynamics and ovarian biomarkers (ERα, ERβ, AR, Ki67, p27) were evaluated. Lambs exposed to DES or BPA showed a decline in the stock of primordial follicles with stimulation of follicular development. BPA reduced ovarian weight and increased the number of multioocyte follicles. BPA promoted proliferation of granulosa/theca cells in antral follicles, and increased both the number of antral atretic follicles and p27 expression. Neonatal exposure to BPA or DES reduced the primordial follicle pool by stimulating their initial recruitment and subsequent follicle development until antral stage. In prepubertal lambs, the accelerated folliculogenesis resulted in increased incidence of atretic follicles. These alterations may affect the ovarian function in the adult. © 2011 Elsevier Inc.

Zachman P.P.,National University of the Chaco Austral | Redchuk A.,National University of Lomas de Zamora
Advances in Intelligent Systems and Computing | Year: 2016

Summary- In recent decades, argentinian u niversities, are inserted into the productive environment from creating business incubators university, turned into one of the mechanisms for technology transfer reference. These companies, known as Spin-Off, ideally arise from the knowledge generated within universities. This paper presents a brief summary, the findings of a study of the main characteristics and current status, degree of technological linkage of argentinian universities geographically located in the north, to the conversion of scientific research in business and commercial value. The information was obtained through semi-structured interviews with a representative sample of spin-off members of accredited at the Ministry of Industry of the Nation and of secondary sources for the analysis of the factors affecting the growth of these companies interviews. The creation of companies born in the university is a complex phenomenon to study multifactorial reasons for intervening in it. This exploratory study can give some guidance to universities not copy a system, but that adapt best practices to their regional needs, academic infrastructure and economic investments and to obtain optimal results in the creation of technology-based companies. © Springer International Publishing Switzerland 2016.

Guida Johnson B.,Maimónides University | Guida Johnson B.,National University of Lomas de Zamora | Zuleta G.A.,Maimónides University | Zuleta G.A.,National University of Lomas de Zamora
Agriculture, Ecosystems and Environment | Year: 2013

Land-use land-cover (LULC) changes are one of the major threats to biodiversity worldwide, since their principal consequences are the loss, fragmentation or degradation of the habitat available for most species. Therefore, in order to provide guidelines for environmental management at the regional scale and thus reverse the trend in degradation, transformations of natural remnants into anthropogenic land uses must be identified and quantified. This study examines LULC transitions from 1987 to 2001 and from 2001 to 2009 in two adjacent watersheds located in the Espinal, one of the least protected ecoregions of Argentina. We detected a 20% loss in ecosystems for the period analyzed and, in particular, 60% of native forests were lost. Changes were mainly driven by the expansion of croplands, which directly transformed wetlands and also acted as an underlying cause of the displacement of ranching activities, which in turn replaced Espinal forests. We developed a conceptual model of observed LULC changes for the study area, which we then complemented by proposing an alternative scenario that reconciles agriculture and biodiversity conservation. These results have implications for provincial land use planning and could contribute to the participatory processes demanded by the recent national legislation sanctioned for the protection of native forests. © 2013 Elsevier B.V.

Alvarez Prado S.,National University of Rosario | Lopez C.G.,National University of Lomas de Zamora | Gambin B.L.,National University of Rosario | Abertondo V.J.,Nidera SA | Borras L.,National University of Rosario
Field Crops Research | Year: 2013

Knowledge on the genetic bases of physiological processes determining maize kernel weight (KW) is relevant for maize yield improvement. However, little is known about the genetic control of KW and its component traits: kernel growth rate (KGR) and grain-filling duration (GFD). We phenotyped several grain-filling traits in 245 RILs from the IBM Syn4 population (B73×Mo17) under two environments, and a multi-trait multi-environment quantitative trait loci (QTL) analysis was conducted. We were specifically interested in seeking genetic links of known correlated traits at the phenotypic level, like kernel maximum water content (MWC) and KGR. Our specific objectives were (i) to conduct a QTL analysis over grain-filling traits to determine their genetic complexity, (ii) to study the relationships between kernel developmental traits at phenotypic and genetic levels, and (iii) to suggest possible candidate genes for each specific trait using detected QTL and B73 sequence data.All traits showed significant genotype × environment interactions (p< 0.001) and large phenotypic variability. KW variability was positively associated (p< 0.01) with variations in KGR (r= 0.79) and GFD (r= 0.32). As expected, KGR was positively correlated to MWC, while GFD was negatively correlated to the kernel moisture concentration at physiological maturity (MCPM). A total of 10 joint QTL were detected under both environments, located on chromosomes 1, 2, 4, 5, 6, 7, 9 and 10. Most QTL showed inconsistent effects underlying genotype × environment interactions. However, the multi-trait multi-environment approach helped understand genetic correlations between traits, where positive and consistent genetic correlations were observed between KW, KGR and MWC on chromosomes 2, 6, 9 and 10. Only one consistent QTL for KW, GFD and kernel desiccation rate (KDR) was detected. KGR and GFD showed no common consistent QTL, supporting previous observations on independent physiological control. Several detected QTL co-localized with previous mapping studies. With the use of B73 sequence data we described genes within QTL marker intervals, and discussed relevant candidate ones for future dissection. Results showing the co-localization of consistent QTL for KW, KGR and MWC suggest a common genetic basis for these critical secondary traits measured under field conditions. © 2013 Elsevier B.V.

Tobon C.,Polytechnic University of Valencia | Ruiz-Villa C.A.,University of Caldas | Ruiz-Villa C.A.,National University of Colombia | Heidenreich E.,National University of Lomas de Zamora | And 3 more authors.
PLoS ONE | Year: 2013

The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block) and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: 1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, 2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, 3) double potentials related with wave fragmentations or blocking lines and 4) fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship between different atrial arrhythmic propagation patterns and the electrograms observed at more than 43000 points on the atrial surface. © 2013 Tobón et al.

Cabra D.C.,National University of La Plata | Cabra D.C.,National University of Lomas de Zamora | Lamas C.A.,National University of La Plata | Rosales H.D.,National University of La Plata
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

In the present paper we study the phase diagram of the Heisenberg model on the honeycomb lattice with antiferromagnetic interactions up to third neighbors along the line J2=J3 that includes the point J 2=J3=J1/2, corresponding to the highly frustrated point where the classical ground state has macroscopic degeneracy. Using the linear spin-wave theory and the Schwinger boson technique followed by a mean field decoupling and exact diagonalization for small systems, we find an intermediate phase with a spin gap and short-range Néel correlations in the strong quantum limit (S=12). All techniques provide consistent results which allow us to predict the existence of a quantum disordered phase, which may have been observed in recent high-field ESR measurements in manganites. © 2011 American Physical Society.

Huarte H.R.,Argentine Catholic University | Huarte H.R.,National University of Lomas de Zamora | Benech-Arnold R.L.,University of Buenos Aires
Seed Science Research | Year: 2010

Cynara cardunculus (L.) seeds require incubation at fluctuating temperatures to terminate dormancy. In this study, we analysed the physiological mechanisms underlying such a requirement, focusing on the role of abscisic acid (ABA) and gibberellin (GA). As a conceptual framework, we considered the possibility that fluctuating temperatures and light trigger a similar set of hormonal processes after stimulus perception. To test this possibility, we (1) carried out hydrotime analysis of germination in seeds exposed to fluctuating temperatures (25/15°C) and constant temperature (20°C) with or without gibberellin (GA3) or red light; (2) determined the responses of seeds incubated at fluctuating or constant temperature to ABA, GA3, fluridone, an inhibitor of ABA biosynthesis, and paclobutrazol, an inhibitor of GA biosynthesis; and (3) determined the ABA content of seeds incubated at fluctuating or constant temperature. Incubation at 25/15°C or 20°C in the presence of GA3 reduced the mean base water potential [b(50)] of the population to a similar extent, compared to that observed with seeds incubated at 20°C without GA3. Irradiation with red light also reduced b(50) to a lesser extent than incubation in the presence of GA3. At all concentrations tested, exogenously applied GA3 did not promote germination of seeds incubated at 25/15°C. However, paclobutrazol inhibited germination, suggesting that fluctuating temperatures terminate dormancy through de novo GA biosynthesis. Fluctuating temperatures enhanced seed germination in the presence of ABA, but ABA content did not differ between seeds incubated at fluctuating and constant temperatures. This study provides clear evidence for the involvement of hormonal regulation in dormancy termination by fluctuating temperatures. Copyright © Cambridge University Press 2010.

Laserna M.P.,University of Buenos Aires | Maddonni G.A.,University of Buenos Aires | Lopez C.G.,National University of Lomas de Zamora
Field Crops Research | Year: 2012

The use of transgenic maize (Zea mays L.) hybrids (Bt, RR, Bt-RR) has simplified crop husbandry, mainly due to a more effective control of pests and weeds. The effects of transgenes insertion on phenotypic traits of maize hybrids are not fully documented, especially without the incidence of pests and weeds. The objectives of this work were (i) to establish phenotypic differences in terms of phenology, growth and yield among a non-transgenic maize hybrid and their transgenic versions (Bt hybrid, RR hybrid and Bt-RR hybrid) and among the transgenic versions of other genetic background and (ii) to analyze the impact of crowding stress on inter-plant variability of the different traits under study. Field experiments were conducted in Buenos Aires (34°36'S, 58°26'W), Argentina during 2008-2009 (Exp 1), 2009-2010 (Exp 2) and 2010-2011 (Exp 3). Genotypes were cultivated at contrasting plant densities (6 and 12plm -2 in Exp 1 and Exp 2) and with contrasting inter-plant spaces within the row (Exp 3), irrigated, without nutrient limitations, and with chemical and mechanical controls of weed and animal pests. At both plant densities, phenotypic variability of several traits among versions within each group was recorded. For example, the RR version of DK747 group had the shortest thermal time to flowering. The stacked transgenic hybrids DK747MGRR and DK190MGRR, exhibited the highest ear growth rate (EGR CP) during the critical period for kernel set. However, both genotypes had the lowest reproductive efficiency (i.e. kernel number per unit of EGR CP), that counterbalanced their higher EGR CP. Only the Bt-RR version of DK747 showed a higher inter-plant variability (CV) of EGR CP at low mean EGR CP values a symptom of the intolerance of this genotype to crowing stress. Consequently, the different versions of each group of hybrids had a similar kernel number per plant and grain yield. We conclude that the introduction of transgenes may alter in some way, the behavior of plants in different eco-physiological aspects in the absence of pests and weeds. © 2012 Elsevier B.V.

Lovisolo M.R.,National University of Lomas de Zamora | Galati B.G.,University of Buenos Aires
Boletin de la Sociedad Argentina de Botanica | Year: 2012

Anthers of ten species of Poaceae from the province of Buenos Aires (Argentina) were investigated with scanning and transmission electron microscopes. The orbicules can be defined as corpuscles of variable size that show the same electron-density, reaction to the dyes, autofluorescence and resistance to acetolysis as pollen exine does. The orbicules are randomly dispersed on the inner anther locule and they are often attached to a tapetal membrane. In this study, four different types and four subtypes of orbicules were identified. We conclude that the different orbicules types described in this work are representative of the studied tribes, and we suggest that the orbicules morphology may be a useful character in systematic studies.

Chena P.,National University of Lomas de Zamora
Journal of Post Keynesian Economics | Year: 2014

This article explores the linkages between the balance of payment and income growth in countries for which exports are mainly food items while imports are mainly industrial goods. To capture the consequence of this structure of international specialization, the study proposes to modify the balance-of-payments-constrained growth "standard" rule (Thirlwall's law) by including the effects of different levels of elasticity of the domestic demand for food. An econometric model is used to test Argentina's behavior on the matter during the period 1976-2006. © 2014 M.E. Sharpe, Inc.

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