Canopy structure analysis for estimating forest regeneration dynamics and growth in Nothofagus pumilio forests. Martínez Pastur, Guillermo José; Peri, Pablo Luis; Cellini, Juan Manuel; Lencinas, María Vanessa; Barrera, Marcelo Daniel; Ivancich, Horacio Simón Introduction Silviculture systems applied in Nothofaguspumilio forests are based on opening the canopy tostimulate natural regeneration by modifying light and soilmoisture. The objective is to evaluate regeneration dynamicsof N. pumilio along different forest canopy and solarradiation gradients.& Materials and methods Regeneration data and seedproduction were obtained in 98 permanent plots establishedin old-growth and harvested stands along a crown covergradient (19?93%). Volumetric soil water content and basalarea were also measured, while crown cover and solarradiation transmission were estimated using hemisphericalphotographs. Sapling height was modeled using plant age,crown cover, and solar radiation transmission of the standsas explanatory variables.& Results Natural regeneration dynamics were closelyrelated to crown cover values, which determined seedproduction and the successful establishment and subsequentregeneration growth. Height growth was found to be relatedto crown cover and solar radiation transmission, where N.pumilio regeneration is optimized at intermediate crowncover levels (45% crown cover, 0.5 effective leaf areaindex, 26 W m2 global radiation, and 65% percentage ofglobal radiation).& Conclusion These findings can be used to develop newsilvicultural methods or to adjust the current practices toensure regeneration establishment and maximize heightgrowth at the stand level.

Phospholipases A in Trypanosomatids Belaunzarán, María Laura; Lammel, Estela María; de Isola, Elvira Luisa Durante Phospholipases are a complex and important group of enzymes widespread in nature, that play crucial roles in diverse biochemical processes and are classified as A1, A2, C, and D. Phospholipases A1 and A2 activities have been linked to pathogenesis in various microorganisms, and particularly in pathogenic protozoa they have been implicated in cell invasion. Kinetoplastids are a group of flagellated protozoa, including extra- and intracellular parasites that cause severe disease in humans and animals. In the present paper, we will mainly focus on the three most important kinetoplastid human pathogens, Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp., giving a perspective of the research done up to now regarding biochemical, biological, and molecular characteristics of Phospholipases A1 and A2 and their contribution to pathogenesis.

Lower complexity bounds for interpolation algorithms Gimenez, Nardo Ariel; Heintz, Joos Ulrich; Matera, Guillermo; Solernó, Pablo Luis We introduce and discuss a new computational model for the HermiteLagrange interpolation with nonlinear classes of polynomial interpolants. We distinguish between an interpolation problem and an algorithm that solves it. Our model includes also coalescence phenomena and captures a large variety of known HermiteLagrange interpolation problems and algorithms. Like in traditional HermiteLagrange interpolation, our model is based on the execution of arithmetic operations (including divisions) in the field where the data (nodes and values) are interpreted and arithmetic operations are counted at unit cost. This leads us to a new view of rational functions and maps defined on arbitrary constructible subsets of complex affine spaces. For this purpose we have to develop new tools in algebraic geometry which themselves are mainly based on Zariski's Main Theorem and the theory of places (or equivalently: valuations). We finish this paper by exhibiting two examples of Lagrange interpolation problems with nonlinear classes of interpolants, which do not admit efficient interpolation algorithms (one of these interpolation problems requires even an exponential quantity of arithmetic operations in terms of the number of the given nodes in order to represent some of the interpolants). In other words, classic Lagrange interpolation algorithms are asymptotically optimal for the solution of these selected interpolation problems and nothing is gained by allowing interpolation algorithms and classes of interpolants to be nonlinear. We show also that classic Lagrange interpolation algorithms are almost optimal for generic nodes and values. This generic data cannot be substantially compressed by using nonlinear techniques. We finish this paper highlighting the close connection of our complexity results in HermiteLagrange interpolation with a modern trend in software engineering: architecture tradeoff analysis methods (ATAM).

A comparative study of the O-3 reactivity of isomeric N-dimethylmaleoyl- protected d-glucosamine and d-allosamine acceptors Colombo, María Inés; Stortz, Carlos Arturo; Ruveda, Edmundo Four isomeric N-dimethylmaleoyl 4,6-O-benzylidene-protected d-hexosamine acceptors (2, 3, 4, and 5) with all possible configurations at C-1 and C-3 (e.g., derived from d-glucosamine and d-allosamine) were prepared, and the assessment of their O-3 relative reactivity through competition experiments using the known per-O-acetylated d-galactopyranosyl trichloroacetimidate donor (15) was then carried out. The reactivities are in the order 4 ≫ 2 > 5 > 3. The analysis of the NMR spectra of 2-5 at different temperature and modeling experiments carried out on analogs of 2-5 (DFT) and on the acceptors themselves (MM) are coincident, and have helped to establish the stability of the different hydrogen bonds, and of the conformers which carry them. The whole results suggest that the electronic effects (hydrogen bonds) are required to explain the observed trend, in spite of the axial conformation of the most reactive hydroxyl group. The steric effects appear only when hydrogen bonds are weak.

Riesgo y derecho, perspectivas sobre el uso de agroquímicos en Argentina Berros, María Valeria El presente trabajo intenta efectuar un aporte sobre la relación entre derecho y riesgos. Para ello se utilizan elementos provenientes de un análisis de caso, el uso de agroquímicos en Argentina, como disparador para escrutar en la temática propuesta. Se recorren las líneas generales de la institucionalización del tema en el ámbito de las agencias estatales y las legislaciones nacionales y locales, lo que permite visibilizar la injerencia de las ciencias y las técnicas en la arquitectura jurídica. Por otro lado, se indaga cómo se traducen las diversas percepciones sociales respecto de la introducción de este riesgo, focalizando en la emergencia de algunos conflictos socio-ambientales y su re-significación al franquear las fronteras de ingreso al campo jurídico.

Relevance of biofilms in pediatric tonsillar disease Diaz, R. R.; Picciafuoco, S.; Paraje, María Gabriela; Villegas, N. A.; Miranda, J. A.; Albesa, Inés; Cremonezzi, David César; Commisso, R.; Paglini Oliva, P. In this investigation, we study the relation between chronic inflammation of the tonsils, clinical features, and the presence of biofilms in the crypts in patients presenting with obstructive hypertrophy and recurrent upper airway pathology. Thirty-six patients who needed to undergo a tonsillectomy for obstructive reasons (aged 1 to 6 years), among which none of them had taken any antibiotics 30 days prior to surgery, were included. Samples were examined with hematoxylin-eosin and Gram staining, fluorescent microscopy, and confocal laser microscopy. The predominance of symptoms were those related to obstructive pathology rather than infection (p∈<∈0.01). All patients had tonsillar hypertrophy (grade III or IV), but an association with adenoids hypertrophy was detected in 66.66% of cases (p∈<∈0.05). 77.28% of tonsils presented biofilms in their crypts, but hypertrophy and tonsillar follicle number were not related to the presence or absence of biofilms. Here, we demonstrated that symptoms like harsh raucous sound, tonsillar and adenoids hypertrophy, apnea, and cervical adenopathies are clearly related to the presence of biofilm in tonsils. Our results allow us to propose that biofilms are involved in the pathogenesis of tonsils and adenoids hypertrophy. The prevention of biofilms formation should be focused in the early stages, attempting to restrain bacterial attachment to the respiratory mucosa.

Convergence of an adaptive Kačanov FEM for quasi-linear problems Garau, Eduardo Mario; Morin, Pedro; Zuppa, Carlos We design an adaptive finite element method to approximate the solutions of quasi-linear elliptic problems. The algorithm is based on a Kačanov iteration and a mesh adaptation step is performed after each linear solve. The method is thus inexact because we do not solve the discrete nonlinear problems exactly, but rather perform one iteration of a fixed point method (Kačanov), using the approximation of the previous mesh as an initial guess. The convergence of the method is proved for any reasonable marking strategy and starting from any initial mesh. We conclude with some numerical experiments that illustrate the theory.

El trabajo infantil como estrategia de sostén de las familias pobres en la Argentina, la necesidad de rediseñar el objeto de las políticas públicas; Child labour as support for poor families in Argentina:the need to revise the objectives of public policies Noceti, Maria Belen La siguiente ponencia pretende discutir a través del análisis de datos obtenidos durante el desarrollo de Proyectos de Investigación Acción llevados adelante desde la Universidad Nacional del Sur, Argentina, la necesidad de rediseñar las políticas publicas existentes en torno a la erradicación del trabajo infantil en la Argentina. En la actualidad este fenómeno social se aborda teniendo como eje de trabajo los individuos, esta ponencia propone que el eje de trabajo necesariamente deben ser los grupos de referencia de los niños trabajadores ya sean grupos de pares o familias, puesto que el trabajo infantil se gesta en una red de relaciones sociales. Siendo así si se erradica debe ofrecer otra red de contención al niño ya que la necesidad de afiliación social es uno de los derechos que como ser humano debe prevalecer. Las políticas publicas deben generar dispositivos de afiliación social que reinserten a los niños en el sistema de educación formal, para ello la educación popular es un instrumento y quizás los técnicos deban diseñar muchos más en función de las características culturales de cada población, en este sentido la antropología puede ofrecer interesantes aportes.; The aim of this research is to discuss the need to revisethe current public policies on the eradication of child labour in Argen-tina by means of the analysis of the data obtained during the develop-ment of research projects carried out by the Universidad Nacional delSur in Argentina. Currently, this social phenomenon is analysed fromthe point of view of the individual. This research suggests that the focusshould instead shift to the working children’s reference groups, whethercouples or families, since child labour is the outcome of a network ofsocial relations. Hence, if child labour is eradicated a different meansof contention should be offered to the child since the need for social affiliation is one of the rights which should prevail for the child as ahuman being. Public policies should create tools for social affiliation facilitating the child’s incorporation into the formal education system.Popular education is a useful tool for achieving this objective, which iswhy professionals should design tools by taking into consideration thecultural aspects of different communities. In this sense, anthropology might offer interesting input.

Earthquake deformation in the northwestern Sierras Pampeanas of Argentina based on seismic waveform modelling Alvarado, Patricia Monica; Ramos, Victor Alberto We investigate the seismic properties of modern crustal seismicity in the northwestern Sierras Pampeanas of the Andean retroarc region of Argentina. We modelled the complete regional seismic broadband waveforms of two crustal earthquakes that occurred in the Sierra de Velasco on 28 May 2002 and in the Sierra de Ambato on 7 September 2004. For each earthquake we obtained the seismic moment tensor inversion (SMTI) and tested for its focal depth. Our results indicate mainly thrust focal mechanism solutions of magnitudes Mw 5.8 and 6.2 and focal depths of 10 and 8km, respectively. These results represent the larger seismicity and shallower focal depths in the last 100 years in this region. The SMTI 2002 and 2004 solutions are consistent with previous determinations for crustal seismicity in this region that also used seismic waveform modelling. Taken together, the results for crustal seismicity of magnitudes ≥5.0 in the last 30 years are consistent with an average P-axis horizontally oriented by an azimuth of 125° and T-axis orientation of azimuth 241° and plunge 58°. This modern crustal seismicity and the historical earthquakes are associated with two active reverse faulting systems of opposite vergences bounding the eastern margin of the Sierra de Velasco in the south and the southwestern margin of the Sierra de Ambato in the north. Strain recorded by focal mechanisms of the larger seismicity is very consistent over this region and is in good agreement with neotectonic activity during the last 11,000 years by Costa (2008) and Casa et al. (in press); this shows that the dominant deformation in this part of the Sierras Pampeanas is mainly controlled by contraction. Seismic deformation related to propagation of thrusts and long-lived shear zones of this area permit to disregard previous proposals, which suggested an extensional or sinistral regime for the geomorphic evolution since Pleistocene.

Candida albicans Tpk1p and Tpk2p isoforms differentially regulate pseudohyphal development, biofilm structure, cell aggregation and adhesins expression Giacometti, Romina; Kronberg, Maria Florencia; Biondi, Ricardo Miguel; Passeron, Susana Candida albicans undergoes a reversible morphological transition from single yeast cells to pseudohyphal and hyphal filaments. In this organism, cAMP-dependent protein kinase (PKA), coded by two catalytic subunits (TPK1 and TPK2) and one regulatory subunit (BCY1), mediates basic cellular processes, such as the yeast-to-hypha transition and cell cycle regulation. It is known that both Tpk isoforms play positive roles in vegetative growth and filamentation, although distinct roles have been found in virulence, stress response and glycogen storage. However, little is known regarding the participation of Tpk1p and/or Tpk2p in pseudohyphal development. This point was addressed using several C. albicans PKA mutants having heterozygous or homozygous deletions of TPK1 and/or TPK2 in different BCY1 genetic backgrounds. We observed that under hypha-only inducing conditions, all BCY1 heterozygous strains shifted growth toward pseudohyphal morphology; however, the pseudohypha:hypha ratio was higher in strains devoid of TPK2. Under pseudohypha-only inducing conditions, strains lacking TPK2 were prone to develop short and branched pseudohyphae. In tpk2Δ/tpk2Δ strains, biofilm architecture was markedly less dense, composed of short pseudohyphae and blastospores with reduced adhesion ability to abiotic material, suggesting a significant defect in cell adherence. Immunolabelling assays showed a decreased expression of adhesins Als1p and Als3p only in the tpk2Δ/tpk2Δ strain. Complementation of this mutant with a wild-type copy of TPK2 restored all the altered functions: pseudohyphae elongation, biofilm composition, cell aggregation and adhesins expression. Our study suggests that the Tpk2p isoform may be part of a mechanism underlying not only polarized pseudohyphal morphogenesis but also cell adherence.

Role of MMPs in Metastatic Dissemination: Implications for Therapeutic Advances Simian, Marina; Raffo, Diego Alejandro; Pontiggia, Osvaldo Alejandro Matrix metalloproteinases (MMPs) have been implicated in both normal and pathologic processes. In cancer in particular, in vitro and animal studies showed an involvement of MMPs in many stages of cancer progression. This led to the development of MMP inhibitors that in most cases failed in clinical trials. In this review we go over the role of MMPs in the different stages of cancer progression and try to understand why the early generation of MMP inhibitors failed. The analysis of the lessons from this first experience, plus the review of the current knowledge that shows that MMPs may be pro-or anti-tumorigenic may set the stage for a future success for this therapeutic strategy in cancer.

Relatos de jóvenes sobre el wichí y el español en sus trayectorias escolares en la provincia de Salta Ossola, María Macarena; Hecht, Ana Carolina Desde una perspectiva antropológica, se sistematizan reflexiones de un grupo de jóvenes wichí acerca de los usos de las leguas wichí y español en sus trayectorias escolares en la provincia de Salta. A partir de retomar sus voces, el análisis ahonda en la complejidad de los procesos de enseñanza y aprendizaje en contextos de diversidad cultural y lingüística.

Primeros ensayos petrofísicos sobre la roca dimensional de Tierra del Fuego; First petrophysical trials over dimension stones of Tierra del Fuego Acevedo, Rogelio Daniel; Gonzalez Guillot, Mauricio Alberto Se muestran aquí los primeros ensayos de laboratorio sobre las rocas dimensionales de Tierra del Fuego, región que tenía una potencialidad no evaluada respecto al uso posible de este recurso nativo. Nunca habían sido empleadas hasta ahora rocas duras (ígneas) ni pizarras en la construcción residencial, el revestimiento de fachadas ó pisos. Dos pequeñas canteras de rocas plutónicas han sido abiertas recientemente: una de ellas en el cerro Jeu-Jepén, aprovechada para la construcción de la escollera marina del puerto de Río Grande y la ruta nacional, y la otra en la península de Ushuaia, iniciada con el propósito de remover un morro para localizar el aeropuerto y usada últimamente como revestimiento de viviendas. Sobre un grupo de muestras fueguinas se realizaron para este trabajo ensayos físicos de densidad aparente, absorción de agua y porosidad abierta, como asimismo ensayos mecánicos de resistencia a la compresión y a la tensión, y también algunos ensayos Dorry para medir su resistencia a la abrasión. En la Isla Grande de Tierra del Fuego los tipos más apropiados como rocas ornamentales han resultado ser las distintas variedades de rocas granitoides, con relativamente altas resistencias a la compresión y a la tensión. Las rocas del cerro Jeu-Jepén analizadas reúnen entonces las mejores condiciones para su aprovechamiento inmediato: buenos resultados petrofísicos, posibilidad de obtención de bloques de tamaño adecuado, descubrimiento de la cantera y fácil acceso.; These are the first trials in laboratory over dimension stones of Tierra del Fuego. The Fuegian territory had a not evaluated potential respect of the possible use of this native resource. Neither hard rocks nor metamorphic rocks (slates) have been applied ever for residential construction, facades and flooring in Fuegian buildings until now. Only in recent years, two little quarries of plutonic rocks have been opened. One of them in the Jeu-Jepen hill, worked firstly to build the breakwaves of Río Grande harbour and then the National railroad. The other one is located in the Ushuaia Peninsula and was started initially to remove a hill for locate the airport and lately used for facings. In the present work, selected stone samples were analysed under standard ASTM test methods for determining compressional strength and modulus of rupture, practiced in accord to IRAM specification for determining apparent density, water absorption and open porosity and Dorry hardness test for measuring the resistance to abrasion. In Isla Grande of Tierra del Fuego the major types of dimension rocks are scarce and randomly distributed granitic bodies, any of them with relatively high compressional and tensional resistance. Therefore, the analyzed rocks of the Jeu-Jepén hill combine among others the best conditions for its immediate use: high petrophysical responses, possibility of obtaining useful-sized blocks, open quarry and easy access.

Revitalización desde las bases del sindicalismo argentino Lenguita, Paula Andrea Reprimidos por la dictadura en la década de los 70 y bloqueados por los sindicalistas empresarios en los 90, los cuerpos de delegados han vuelto al escenario sindical argentino. Este artículo reflexiona sobre la reemergencia de un sindicalismo de base, a menudo alentado por jóvenes sin experiencia gremial, que ha logrado éxitos resonantes como en el caso de los trabajadores del transporte subterráneo de Buenos Aires. En el marco de direcciones sindicales burocratizadas e incapaces de transmitir la experiencia del pasado, muchos de los nuevos activistas se han visto influidos por luchas fuera del lugar de trabajo, como asambleas barriales, corte de ruta o la militancia en partidos de izquierda.

Organization of the synthesis of glycolipid oligosaccharides in the Golgi complex Maccioni, Hugo Jose Fernando; Quiroga, Rodrigo; Spessott, Waldo Andrés Glycolipids constitute a complex family of amphipathic molecules structurally characterized by ahydrophilic mono- or oligo-saccharide moiety linked to a hydrophobic ceramide moiety. Due totheir asymmetric distribution in cell membranes, exposing the saccharide moiety to the extracytoplasmicside of the cell, glycolipids participate in a variety of cell?cell and cell?ligand interactions.Here we summarize aspects of the cell biology of the stepwise synthesis of the saccharide moiety inthe Golgi complex of cells from vertebrates. In particular we refer to the participant glycosyltransferases,with emphasis on their trafficking along the secretory pathway, their retention and organizationin the Golgi complex membranes and their dependence on the Golgi complex ultra structuralorganization for proper function.

Robust model predictive control of Wiener systems Biagiola, Silvina Ines; Figueroa, Jose Luis Block-oriented models (BOMs) have shown to be appealing and efficient as nonlinear representations for many applications. They are at the same time valid and simple models in a more extensive region than time-invariant linear models. In this work, Wiener models are considered. They are one of the most diffused BOMs, and their structure consists in a linear dynamics in cascade with a nonlinear static block. Particularly, the problem of control of these systems in the presence of uncertainty is treated. The proposed methodology makes use of a robust identification procedure in order to obtain a robust model to represent the uncertain system. This model is then employed to design a model predictive controller. The mathematical problem involved in the controller design is formulated in the context of the existing linear matrix inequalities (LMI) theory. The main feature of this approach is that it takes advantage of the static nature of the nonlinearity, which allows to solve the control problem by focusing only in the linear dynamics. This formulation results in a simplified design procedure, because the original nonlinear model predictive control (MPC) problem turns into a linear one.

Para una crítica a los medios masivos. Consideraciones a partir del caso argentino Fair, Hernán Resulta común creer que los medios de comunicación masivos median sobre la realidad social, actuando como un vínculo democrático que nos informa de modo objetivo e imparcial sobre los acontecimientos sociales. El siguiente ensayo se propone cuestionar esta representación social hegemónica. Para ello, parte de la base de que los medios masivos son empresas concentradas, lo que limita su supuesta mediación objetiva y plural de la realidad.; It is commonly believed that mass media mediate social reality, acting as a democratic link that informs us of an objective and impartial on the social events. This essay seeks to challenge this hegemonic social representation. To do so, assumes that the mass media are concentrated companies, which limits their alleged objective and plural mediation of reality.

Synthesis, characterization and performance of membranes for clarification of lemon juice Chornomaz, Patricia Mariana; Ochoa, Nelio Ariel; Pagliero, Cecilia Liliana; Marchese, Jose Two membranes named M1 and M2 from polysulfone (PSF) and polyvinylidenefluoride (PVDF), respectively, were prepared in our laboratory in order to determine their structural characteristics and to evaluate their efficiency in lemon juice clarification. Both membranes were characterized by scanning electron microscopy (SEM), liquid-liquid displacement, contact angle measurements, and the water permeability (Lh). Asymmetric membranes with a sponge-like and finger-like substructure for M1 and M2, respectively, were obtained. M1 PSF membrane had a smaller pore size and a higher porosity than PVDF but it had a higher value of permeate flux and lower fouling. The quality of clarified juice was evaluated in terms of: total soluble solids (TSS), suspended solids (TS), pH, citric acid content (% citric ac.). The resulting clarified lemon juice was highly similar to the initial juice but the reduction of the hesperidin (HSP) was lower for M2 (34%) when is compared to M1 (41%).

Clases altas y clases medias en la Argentina, 1880-1930: notas para una agenda de investigación Hora, Roy; Losada, Leandro Agustín Este ensayo explora las relaciones entre la elite social y las clases medias en el período 1880-1930. En particular, presenta algunas hipótesis acerca de las circulaciones culturales y las influencias recíprocas entre los estilos de vida y las convenciones sociales de los sectores medios y los grupos encumbrados. Luego de una breve caracterización de ambos grupos, este ensayo sugiere que el ascendiente de la elite social, de gran importancia en el cambio de siglo, comenzó a menguar hacia el Centenario. El ensayo explora los procesos que afectaron el influjo de la elite, y dieron lugar a la emergencia de una sociedad y una cultura que poseían su centro de gravedad en las clases medias.; This essay analyses the relationship between the social elite and the middle classes in Argentina during the 1880-1930 period. It focuses on the way the upper and middle class interacted in the realm of social customs and lifestyle. The essay offers a brief description of both groups, and then argues Este ensayo explora las relaciones entre la elite social y las clases medias en el período 1880-1930. En particular, presenta algunas hipótesis acerca de las circulaciones culturales y las influencias recíprocas entre los estilos de vida y las convenciones sociales de los sectores medios y los grupos encumbrados. Luego de una breve caracterización de ambos grupos, este ensayo sugiere que el ascendiente de la elite social, de gran importancia en el cambio de siglo, comenzó a menguar hacia el Centenario. El ensayo explora los procesos que afectaron el influjo de la elite, y dieron lugar a la emergencia de una sociedad y una cultura que poseían su centro de gravedad en las clases medias. that the ascendancy of the social elite peaked at the turn of the century, and thereafter lost much of its former force. Finally, the essay looks at the way in which the middle classes became the central element of Argentine culture and society, displacing the elite from its former dominant position.

A 50 años de "Producción de Mercancías por medio de Mercancías" de Piero Sraffa Crespo, Eduardo; Lazzarini, Andrés Lucas Rodrigo Este artículo discute los puntos salientes del libro de Piero Sraffa "Producción de mercancías por medio de mercancías" (1960) en el 50 aniversario de su publicación. Se examinan los antecedentes históricos de la obra y la estrecha relación entre la teoría de la distribución de la economía clásica y la obra del economista Italiano. También se subrrayan algunos de los factores que podrían ayudar a explicar el impacto de la obra en la disciplina en general.