Isolation of Bacteria from Remote High Altitude Andean Lakes Able to Grow in the Presence of Antibiotics Dib, Julian Rafael; Weiss, Annika; Neumann, Anna; Ordoñez, Omar Federico; Estévez, Maria Cristina; Farias, Maria Eugenia High altitude Andean lakes are placed in Puna desert over 4400 above sea level. Completely isolated, they are exposed to extreme environmental factors like high levels of salinity, UV radiation and heavy metals and low concentrations of phosphorus. Nevertheless, they are the habitat of enormous populations of three flamingo species that migrate among these Lakes. Previous reports have determined that bacteria isolated from these environments present high levels of resistance to antibiotics. The aim of this work was to determine the diversity of antibiotic resistant bacteria in water from Andean Lakes and their connection with flamingo enteric biota. Bacteria from water and birds faeces from high altitude Lakes: Laguna (L.) Aparejos, L. Negra, L. Vilama and L. Azul (all are located between 4,200 and 4,600 m altitude) were isolated by plating in five different Antibiotics (ampicillin, 100 microg ml(-1); chloramphenicol, 170 microg ml(-1); colistin , 20 microg ml(-1); erythromycin, 50 microg ml(-1) and tetracycline 50 microg ml(-1)). 56 bacteria were isolated and identified by 16 S rDNA sequencing. Antibiotic resistance profiles of isolated bacteria were determined for 22 different antibiotics. All identified bacteria were able to growth in multiple ATBs. Colistin, ceftazidime, ampicillin/sulbactam, cefotaxime, cefepime, cefalotin, ampicillin and erythromycin were the most distributed resistances among the 56 tested bacteria. The current results demonstrated that antibiotic resistance was abundant and diverse in high altitude Lakes. Also the present article indicates some useful patents regarding the isolation of bacteria able to grow in the present of antibiotics.

Addition to the knowledge of Xylaria (Xylariaceae, Ascomycota) in Santa Catarina, Southern Brazil Trierveiler Pereira, Larissa; Romero, Andrea Irene; Baltazar, Juliano Marcon; Loguercio Leite, Clarice Xylaria specimens have been collected in the State of Santa Catarina, Southern Brazil, since the 19th century, primarily by European naturalists such as Ernst Ule and Alfred Möller. Few comprehensive surveys or Xylaria collections have been made by Brazilians in the State until recently. New knowledge has been gained from the authors' recent survey and examination of specimens from the Florianópolis metropolitan area. Among the species discussed are a new species, Xylaria nigromedullosa, and eleven other species, including X. adscendens, X. allantoidea, X. anisopleura, X. comosa, X. cubensis, X. curta, X. ianthinovelutina, X. magnoliae var. microspora, X. mellissii, X. obovata, and X. telfairii. Most collections were obtained from dead wood, with a few found growing on fallen fruits. Seven species are new records from Santa Catarina and X. magnoliae is a new record for Brazil. Full descriptions, illustrations, and a key to the Xylaria collections now curated in FLOR are provided.

Involvement of nitric oxide synthase in the mechanism of histamine-induced inhibition of Leydig cell steroidogenesis via histamine receptor subtypes in Sprague-Dawley rats Mondillo, Carolina; Pagotto, Romina María del Luján; Piotrkowski, Barbara; Reche, Cecilia; Patrignani, Zoraida Judith; Cymeryng, Cora Beatriz; Pignataro, Omar Pedro The present study was conducted to shed light on the so far unexplored intracellular mechanisms underlying negative modulation of Leydig cell steroidogenesis by histamine (HA). Using the MA-10 cell line and highly purified rat Leydig cells as experimental models, we examined the effect of the amine on biochemical steps known to be modulated by HA, or involved in LH/hCG action. In agreement with previous findings, HA at 10 microM showed a potent inhibitory effect on hCG-stimulated steroid synthesis, regardless of the gonadotropin concentration used. Moreover, HA not only decreased LH/hCG-induced cAMP production but also steroid synthesis stimulated by the permeable cAMP analog dibutyryl cAMP (db-cAMP). Considering the post-cAMP sites of HA action, it is shown herein that HA markedly inhibited db-cAMP-stimulated acute regulatory (STAR) protein expression, as well as steps catalyzed by P450-dependent enzymes, mainly the conversion of cholesterol to pregnenolone by cholesterol side-chain cleavage enzyme (CYP11A). The antisteroidogenic action of HA was blocked by addition of the PLC-inhibitor U73122, and HA significantly augmented IP3 production, suggesting a major role for the PLC/IP3 pathway in HA-induced inhibition of Leydig cell function. Finally, HA increased nitric oxide synthase (NOS) activity, and the NOS inhibitor L-N(G)-nitro-arginine methyl ester (L-NAME) markedly attenuated the effect of the amine on steroid synthesis. On the basis of our findings, HA antagonizes the gonadotropin action in Leydig cells at steps both pre- and post-cAMP formation. NOS activation is the main intracellular mechanism by which HA exerts its antisteroidogenic effects.

Photocatalytic degradation of Dichloroacetic acid: a kinetic study with a mechanistically based reaction model Ballari, Maria de Los Milagros; Alfano, Orlando Mario; Cassano, Alberto Enrique In the present work, a study of the reaction kinetics of the photocatalytic degradation of dichloroacetic acid (DCA) employing UV radiation and titanium dioxide suspensions is reported. This study involved the development of a kinetic model from a proposed complete reaction sequence and estimation of the kinetic parameters from experimental data. The experimental data were obtained using a perfect mixed photoreactor, because the operating conditions were chosen in compliance with restrictive conditions established in a previous work in which the possibility of mass-transfer limitations in slurry reactors was investigated. The significant variables in this study were (1) the initial DCA concentration, (2) the catalyst loading, and (3) the light intensity. Simulation results from the complete reactor mass balance, including radiation transport in the bulk and resistances inside the catalytic particle agglomeration, are in good agreement with  experiments, which provides confidence in the estimation of the kinetic parameters within the range of the explored variables.

Dynamics of sonoluminescing bubbles within a liquid hammer device Urteaga, Raul; Garcia Martinez, Pablo Luis; Bonetto, Fabian Jose We studied the dynamics of a single sonoluminescing bubble (SBSL) in a liquid hammer device. In particular, we investigated the phosphoric acid–xenon system, in which pulses up to four orders of magnitude brighter than SBSL in water systems (about 1012 photons per pulse)have been previously reported [Chakravarty et al., Phys. Rev. E 69, 066317 (2004)]. We used stroboscopic photography and a Mie scattering technique in order to measure the radius evolution of the bubbles. Under adequate conditions we may position a bubble at the bottom of the tube (cavity) and a second bubble trapped at the middle of the tube (upper bubble). During its collapse, the cavity produces the compression of the liquid column. This compression drives impulsively the dynamics of the upper bubble. Our measurements reveal that the observed light emissions produced by the upper bubble are generated at its second collapse. We employed a simple numerical model to investigate the conditions that occur during the upper bubble collapse. We found good agreement between numerical and experimental values for the light intensity (fluence) and light pulse widths. Results from the model show that the light emission is increased mainly due to an increase in noble gas ambient radius and not because the maximum temperature increases. Even for the brightest pulses obtained (2x1013 photons, about 20 W of peak power) the maximum temperatures computed for the upper bubble are always lower than 20000 K.

Electrodeposition of CuInSe2 and In2Se3 on flat and nanoporous TiO2 substrates Valdes, Matias Hernan; Vazquez, Marcela Vivian; Goossens, A. In2Se3 and CuInSe2 films have been prepared by potentiostatic electrodeposition from deareated aqueous solutions. The substrate consisted of a duplex layer of dense and nanoporous TiO2 obtained by spray pyrolysis deposition (SPD) and doctor blading. In2Se3 thin films are electrodeposited in between the TiO2/CuInSe2 pn heterojunction to block the electron back flow and lower the interfacial recombination produced upon illumination. The films have been characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and optical transmission. Annealing the samples in Se atmosphere is essential to improve the crystallinity of the In2Se3 and CuInSe2 films. The combination of TiO2/In2Se3/CuInSe2 shows very good diode behavior with a rectification ratio higher than 100 at ±1 V.

Las empresas centenarias de Rosario y su región: Molino Victoria S.A. y Alabern Fábrega y Cía. S.A. de Marco, Miguel Angel L. La ubicación estratégica de la firma Molino Victoria. La localidad de María Juana en la década del 80 del siglo XIX. La familia Boero. Evolución del Molino. La relación de los Boero y la Bolsa de Comercio de Rosario. El siglo XX. Federico Alabern y los comienzos de la firma Alabern Fábrega y Cía. Ernesto Fábrega: la ampliación del campo de acción. La sociedad anónima. Los funcionarios de la firma y su inserción de las instituciones rosarinas. Los Weskamp: ciencia, empresa y vinculación internacional. La firma en la segunda mitad del siglo XX.

Fire retardant impregnants for woods based on alkaline silicates Pereyra, Andrea Marisa; Giudice, Carlos Alberto The aim of this paper was to determine the fire performance of wood panels (Araucaria angustifolia) impregnated in a pressure vessel with post-cured alkaline silicates (water glasses). Several commercial silicates based on sodium ions and potassium ions with 3.0/1.0 and 3.5/1.0 silica/alkali molar ratios were selected. Various treatments for curing were applied for polymerization, creating metal silicate polymers of high water insolubility. Experimental panels were tested in a limiting oxygen chamber (limiting oxygen index) and in a twofoot tunnel (flame-spread index and panel consumption). Test results displayed a high fire-retardant efficiency of some post-cured alkaline silicates.

50 años de CONICET: los avatares de la ciencia Hurtado de Mendoza, Diego Fabian; Feld, Adriana La historia del CONICET está marcada por una trayectoria errática. Nacido durante un gobierno dictatorial, el organismo estatal dedicado a la investigación científica y tecnológica sufrió las oscilaciones de la vida institucional del país, con gobiernos civiles y militares y la falta de una estrategia a largo plazo, que hoy intenta revertir, de cara a un proceso a futuro que vincule la indagación con la producción. Estos son algunos de los lineamientos que sigue este artículo.

Insertion/Deletion Polymorphisms in Indian Tribal Populations Veerraju, P.; Demarchi, Dario; Lakshmi, N.; Venkateswara Rao, T. Five Alu markers (Alu APO, PV 92, TPA 25, D1 and ACE) were studied in five tribal populations namely, Konda Reddi, Koya Dora and Konda Kammara of East Godavari district, Lambada and Chenchu of Mahaboobnagar district of Andhra Pradesh. All the five loci were found to be highly polymorphic. While the lowest heterozygosity was observed in the Chenchu the Lambadi shows the highest. Both Neighbour Joining tree and Principal Component analysis based on genetic distances suggest two broad clusters, one formed by the Lambada and Chenchu and the other by the Konda Reddi and Koya Dora with Konda Kammara as an outer element to this three-point cluster. Another cluster analysis carried out along with 19 other Indian populations brings out no distinct cluster of the 5 AP tribes; instead these AP tribal populations are integrated into different subclusters of the UP and Bengal suggesting lack of distinct genetic identity of these AP tribes as far as the few Alu markers are concerned.

A general tumour control probability model for non-uniform dose distributions González, Sara Josefina; Carando, Daniel Germán Perfectly uniform dose distributions over target volumes are almost impossible to achieve in clinical practice, due to surrounding normal tissues dose constraints that are commonly imposed to treatment plans. This article introduces a new approach to compute tumour control probabilities (TCPs) under inhomogeneous dose conditions. The equivalent subvolume model presented here does not assume independence between cell responses and can be derived from any homogeneous dose TCP model. To check the consistency of this model, some natural properties are shown to hold, including the so-called uniform dose theorem. In the spirit of the equivalent uniform dose (EUD) concept introduced by Niemierko (1997, Med. Phys., 24, 103–110), the probability-EUD is defined. This concept together with the methodology introduced to compute TCPs for inhomogeneous doses is applied to different uniform dose TCP models. As expected, the TCP takes into account the whole dose distribution over the target volume, but it is influenced more strongly by the low-dose regions. Finally, the proposed methodology and other approaches to the inhomogeneous dose scenario are compared.

Protesta social y cultura política: aportes para pensar los años ‘90 en Neuquén; Social protest and political culture: contributions for the interpretation of the 90´ in Neuquén Aiziczon, Fernando Cristian Durante la década del ´90 la provincia norpatagónica de Neuquén vive un intenso proceso caracterizado por una fuerte conflictividad social, anclada en un contexto particular y con diversos actores como protagonistas, con renovados contenidos y prácticas, aunque también impregnada por el rescate de ciertas tradiciones discursivas que remiten a un pasado combativo. Lo distintivo de Neuquén y que pretendo señalar aquí, parece ser la configuración de un campo de protesta social que se despliega en dos direcciones: a) como lugar simbólico para el resto de los fenómenos de protesta social en la Argentina de la década del ’90 (p.e. las organizaciones piqueteras), y b) como momento emergente de una cultura política que tras las puebladas cutralquenses de 1996/97 adquiere un claro perfil contestatario.; During the 90’s, the northern patagonic province of Neuquén goes through a very intense process, marked by strong social conflicts, anchored in a special context and with different kinds of actors in the leading roles. This process includes new practices and contents, though it is also permeated by certain speech traditions that reminds of a struggling pass. The distinctive tract of Neuquen –and I intend to point it here- seems to be the creation of a field for social protest that spreads towards two directions: a) as a symbolic place for the rest of the social protest phenomena in the 90’s of Argentina (v.g., the “piqueteros” (picketing) organizations), and b) as the emerging moment of a political culture that gets a clear defiant profile, after the village upraisings of Cutral Co during 1996/7.

How to Approximate the Heat Equation with Neumann Boundary Conditions by Nonlocal Diffusion Problems Cortazar, Carmen; Elgueta, Manuel; Rossi, Julio Daniel; Wolanski, Noemi Irene We present a model for nonlocal diffusion with Neumann boundaryconditions in a bounded smooth domain prescribing the flux throughthe boundary. We study the limit of this family of nonlocaldiffusion operators when a rescaling parameter related to thekernel of the nonlocal operator goes to zero. We prove that thesolutions of this family of problems converge to a solution of theheat equation with Neumann boundary conditions.

Ultrastructure and potential taxonomic importance of euspermatozoa and paraspermatozoa in the volutid gastropods Zidona dufresnei and Provocator mirabilis (Caenogastropoda, Mollusca) Giménez, Juliana; Healy, John M.; Hermida, Gladys Noemí; Lo Nostro, Fabiana Laura; Penchaszadeh, Pablo Enrique The ultrastructure of mature spermatozoa is investigated for the first time in the Volutidae, based on the commercially significant South American species Zidona dufresnei (Donovan, 1823) (fresh material) and supplemented with observations on testicular (museum) material of the deep sea New Zealand species Provocator mirabilis (Finlay, 1926). Euspermatozoa of Z. dufresnei (ex sperm duct) consist of: (1) a tall-conical acrosomal vesicle (with short basal invagination, constricted anteriorly) which is flattened anteriorly and associated with an axial rod, centrally perforate basal plate and short accessory membrane; (2) a rod-shaped, solid and highly electron-dense nucleus (with short basal fossa containing centriolar complex and initial portion of a 9 + 2 axoneme); (3) an elongate midpiece consisting of the axoneme sheathed by 5–6 helical mitochondrial elements, each exhibiting a dense U-shaped outer layer; (4) an elongate glycogen piece (axoneme sheathed by nine tracts of putative glycogen granules); (5) a dense annulus at the junction of the midpiece and glycogen piece and (6) a short free tail region (axoneme surrounded only by plasma membrane). Paraspermatozoa of Z. dufresnei are vermiform and dimorphic: the first type contains approximately 14–20 axonemes (arranged peripherally and interspersed with microtubules) and numerous oblong dense vesicles, numerous less dense (round) vesicles, occasional, large lipid-like vesicles, and scattered mitochondria; the second type contains 25–31 axonemes (peripherally arranged, interspersed with microtubules), occasional mitochondria and extensive cytoplasm. Results obtained for P. mirabilis from testis material are essentially as observed in Z. dufresnei, although the euspermatozoan acrosome still has to achieve its compressed transverse profile. Observations on paraspermatozoa were limited by fixation quality of available (testis) tissues, but these cells are similar to the first type of Zidona paraspermatozoa. Although most of the euspermatozoal features are also observed in many neotaenioglossans and neogastropods, the U-shaped outer layer of each mitochondrial element has not previously been reported and may prove a diagnostic feature of the Volutidae, the subfamily Zidoniinae or possibly only the Zidonini (in which Z. dufresnei and P. mirabilis are currently placed).

Acerca de una inhumación temprana (CA. 2500 AP) en el sitio Cruz Chiquita 3 (Valle de Salsacate, Córdoba, Argentina) Pastor, Sebastián Se presentan los resultados del estudio de una inhumación localizada en el sitio Cruz Chiquita 3, en el valle de Salsacate, al occidente de la provincia de Córdoba (Argentina). La misma cuenta con una datación temprana -ca. 2500 AP- obtenida por AMS a partir de la fracción de colágeno de una muestra ósea. Se busca contextualizar el caso considerando los tratamientos mortuorios a escala regional. En tal sentido, se evalúan tendencias homogeneizantes y diversificadoras, así como continuas y discontinuas, observadas en torno a dichos tratamientos a lo largo de un extenso período. Por otra parte, el análisis de los fitolitos asociados al tártaro de las piezas dentarias permitió reconocer la presencia de maíz (Zea mays), en una fecha temprana para las Sierras de Córdoba y en general para el área Andina Meridional. A partir de la información disponible a escala regional y macro-regional, se considera la conveniencia de interpretar o no estos datos en términos de una producción agrícola local.; This paper presents the study of a burial found in Cruz Chiquita 3, a site located in Salsacatevalley, in the western sector of Córdoba province, Argentina. AMS dating of a human bone samplereveals an antiquity of 2500 BP. The mortuary practices are evaluated on a regional scale in order tocontextualize the case. We analyze the degree of diversity/homogeneity, and continuity/discontinuityof the trends regarding mortuary practices for a long period. In parallel, the phytolithic analysis ofteeth reveals the presence of maize (Zea mays), in an early time for Córdoba Hills and in general for theSouth Andes region. We evaluate the potential existence of a local agricultural production, in accordancewith available information at a regional and macro-regional scale.

A triangular finite element with local remeshing for the large strain analysis of axisymmetric solids Castello, Walter Braulio; Flores, Fernando Gabriel In this work a three-node triangular finite element with two degrees of freedom per node for the large strain elasto-plastic analysis of axisymmetric solids is presented. The formulation resorts to the adjacent elements to obtain a quadratic interpolation of the geometry over a patch of four elements from which an average deformation gradient is defined. Thus the element formulation falls within the framework of assumed strain elements or more precisely of F-bar type formulations. The in-plane behavior of the element is similar to the linear strain triangle, but without the drawbacks of the quadratic triangle, e.g. contact or distortion sensitivity. The element does not suffer of volumetric locking in problems with isochoric plastic flow and the implementation is simple. It has been implemented in a finite element code with explicit time integration of the momentum equations and tools that allow the simulation of industrial processes. The widely accepted multiplicative decomposition of the deformation gradient in elastic and plastic components is adopted here. An isotropic material with non-linear isotropic hardening has been considered. Two versions of the element have been implemented based on a Total and an Updated Lagrangian Formulation respectively. Some approximations have been considered in the latter formulation aimed to reduce the number of operations in order to increase numerical efficiency. To consider bulk forming, with large geometric changes, an automatic local remeshing strategy has been developed. Several examples are considered to assess the element performance with and without remeshing.

A new search strategy for microquasar candidates using NVSS/2MASS and XMM-Newton data Combi, Jorge Ariel; Albacete Colombo, Juan Facundo; Martí, Josep Aims.Microquasars are ideal natural laboratories for understanding accretion/ejection processes, studying the physics of relativistic jets, and testing gravitational phenomena. Nevertheless, these objects are difficult to find in our Galaxy. The main goal of this work is to increase the number of known systems of this kind, which should allow better testing of high-energy phenomena and more realistic statistical studies of this galactic population to be made. Methods: We have developed an improved search strategy based on positional cross-identification with very restrictive selection criteria to find new MQs, taking advantage of more sensitive modern X-ray data. To do this, we made combined use of the radio, infrared, and X-ray properties of the sources, using different available catalogs. Results: We find 86 sources with positional coincidence in the NVSS/XMM catalogs at galactic latitudes |b| ¡Ü 10¡ã. Among them, 24 are well-known objects and the remaining 62 sources are unidentified. Out of 86 sources, 31 have one or two possible infrared counterparts in the 2MASS catalog. For the fully coincident sources, whenever possible, we analyzed color-color and hardness ratio diagrams and found that at least 3 of them display high-mass X-ray binary characteristics, making them potential microquasar candidates.

La savia del tiempo. Apuntes para una concepción relacional del tiempo; The sap of time. Notes for a relational conception of time Garrido Maturano, Ángel Enrique El artículo primero «abre» la tijera del tiempo y muestra por qué tiempo cósmico y tiempo vivido son irreductibles uno a otro. En segundo lugar «afila» las hojas de la tijera y analiza tanto tiempo cósmico cuanto tiempo vivido como categorías relacionales y la alteridad como conditio sine qua non de la efectividad del tiempo. En tercer lugar «cierra» la tijera señalando los rasgos formales comunes a tiempo cósmico y vivido. Finalmente se pregunta en qué medida estos rasgos comunes presuponen un sentido religioso último del tiempo; The article first «opens» the scissors of time, and shows why cosmic time and lived time are irreducible one to another. Second, it «sharpens» the blades of the scissors an analyzes both cosmic time and lived time as relational categories, and alterity as the conditio sine qua non of the actuality of time. Third, the article «closes» the scissors by pointing out the formal traits common to cosmic and lived time. Fainally, it raises the question about how far these common features presuppose an ultimate religious meaning of time.

The spatial orientation of Planetary Nebulae within the milky way Weidmann, Walter Alfredo; Diaz, Ruben Joaquin We analyze the spatial orientation of a homogenous sample of 440 elongated Planetary Nebulae (PNe) in order to determine the orientation of their apparent major axis with respect to the Milky Way plane. We present some important geometrical and statistical considerations that have been overlooked by previous works on the subject. The global distribution of galactic position angles (GPA) of PNe is quantitatively not very different from a random distribution of orientations in the Galaxy. Nevertheless, we find that there is at least one region on the sky, toward the Galactic center, where a weak correlation may exist between the orientation of the major axis of some PNe and the Galactic equator, with an excess of axes with GPA ∼100°. Therefore, we confirm that "extrinsic" phenomena (i.e., global Galactic magnetic fields, shell compression from motion relative to the Interstellar Medium) do not determine the morphology of PNe on most of the sky, with a possible exception toward the Galactic center.

Aportes de la enseñanza de la autogestión a la construcción de proyectos de vida diferentes. Una experiencia con mujeres trabajadoras del conurbano bonaerense Miano, María Amalia; Heras Monner Sans, Ana Ines; Burin, David En este escrito analizamos una experiencia pedagógica que se desarrolló con mujeres en una localidad del conurbano bonaerense y que tuvo como objetivo enseñar a sus participantes algunos conceptos básicos acerca del cooperativismo de trabajo. Nos propusimos reflexionar sobre: 1) los aprendizajes incorporados por las mujeres en el proceso de la experiencia pedagógica en función de la historia de los grupos de trabajo que conforman y de las concepciones previas que tenían acerca del cooperativismo y, 2) los criterios y dispositivos que organizaron la enseñanza a partir de analizar las interacciones que tuvieron lugar en las jornadas de capacitación. Para esto nos preguntamos desde el enfoque etnográfico y la sociolinguística de la interacción ¿quién enseña qué, a quién y con qué resultados identificables, al menos a corto plazo?; In this article we analyze an educational experience aimed at teaching basic concepts on worker cooperatives to women living in a small town in the peripheral Buenos Aires area. We present our findings organized around two themes: (1) what this educational experience contributed to accessing knowledge on the basic procedures and ideas that ground worker cooperatives, by analyzing participants´ processes of change over time; (2) the educational tools and criteria that framed the educational process itself, by analyzing face to face interactions that took place during the teaching and learning experience. We have used an 2 ethnographic and interactional sociolinguistic approach to answer an underlying question: who teaches what, to whom, and with what identifiable results, at least in the short term?