Hidrogeología de Argentina; Hydrogeology of Argentina Auge, Miguel Pedro; Wetten, Cristian; Baudino, Guillermo; Bonorino, Alfredo Guillermo; Gianni, R.; González, N.; Grizinik, M.; Hernandez, Mario Alberto; Rodríguez, J.; Sisul, Ana Clara; Tineo, Alfredo; Torres, C. Se mencionan las características hidrogeológicas de la República Argentina, en su ámbito continental que ocupa 2.800.000 km2 y otro que contiene a la Antártida Argentina, Islas Malvinas, Georgias, Sandwich, Orcadas y Shetland, del Sur, en 1.000.000 de km2 adicionales. Para la caracterización se subdividió al territorio en 18 regiones hidrogeológicas, sobre la base de la incidencia que ejercen en el agua subterránea, los componentes geológico, climático, geomórfico y biótico. Además, se citan los usos actuales del agua y los previstos en el futuro, como así también los conflictos derivados de su empleo. Finalmente se sintetiza el ordenamiento institucional y legal, referidos a los recursos hídricos.; The hydrogeologic behavior of the Argentine Republic is mentioned, in their continental environment that occupies 2,800,000 km2 and another that contains the Argentine Antartic and the islands of Malvinas, Georgias, Sandwich, Orcadas and Shetland, of the South (1,000,000 additional km2). For the characterization the territory was subdivided in 18 hydrogeologic regions, on the base of the incidence that exert in the groundwater, the geologic, climatic, geomorphic, and biotic components. The current uses of the water are mentioned and it forseen in the future, how so also the conflicts derived of their employment. Finally the institutional and legal arrangement referred to the water resources is synthesized.

Pressure sensitivity of the ferromagnetic transition in perovskite manganites revisited Garbarino, Gaston Leonel; Acha, Carlos Enrique; Polla, Gabriela Maria; Leyva, Adelma Graciela It was already shown that a qualitative understanding of the pressure effects on the ferromagnetic transition temperature (Tc) of the perovskite manganites (AMnO3) results from the variation of the geometric factors that control the bandwidth, the Mn-O-Mn bond angle and the Mn-O bond length and also from the reduction of the effective mass related to the polaronic nature of the carriers. But, up to now, a quantitative agreement was not really obtained, particularly for the hole-doped manganites. Here, we present results on the pressure effects in the Tc of La 0.8(Ca,Sr)0.2MnO3 ceramic samples. Our results are described within a phenomenological approach based on the well known dependence of Tc on the mean A ionic radius, that gives a good quantitative agreement of the pressure sensitivity of Tc for several hole-doped manganites. © 2006 American Institute of Physics.

CDW and CDW-EIS calculations for FDCSs in highly charged ion impact ionization of helium Ciappina, Marcelo Fabián; Cravero, Walter Ruben In this work we present fully differential cross sections (FDCS) calculations using CDW and CDW-EIS theories for helium single ionization by 100 MeV/amu and 2 MeV/amu C6+ and 3.6 MeV/amu Au24+ and Au53+ ions. We performed our calculations for different momentum transfers and ejected electron energies. We study the influence of the internuclear potential on the ejected electron spectra. We discuss different regimes where the internuclear interaction can or cannot be neglected. We compare our calculations with experimental data available. It is shown that for high impact energy and small momentum transfer, internuclear potential effects can be neglected in FDCSs.

Classification of dispersion equations for homogeneous, dielectric-magnetic, uniaxial materials Depine, Ricardo Angel; Inchaussandague, Marina Elizabeth; Lakhtakia, Akhlesh The geometric representation at a fixed frequency of the wave vector (or dispersion) surface ω(k) for lossless, homogeneous, dielectric-magnetic uniaxial materials is explored for the case when the elements of the relative permittivity and permeability tensors of the material can have any sign. Electromagnetic plane waves propagating inside the material can exhibit dispersion surfaces in the form of ellipsoids of revolution, hyperboloids of one sheet, or hyperboloids of two sheets. Furthermore, depending on the relative orientation of the optic axis, the intersections of these surfaces with fixed planes of propagation can be circles, ellipses, hyperbolas, or straight lines. The understanding obtained is used to study the reflection and refraction of electromagnetic plane waves due to a planar interface with an isotropic medium. © 2006 Optical Society of America.

Plane-Wave Diffraction at a Periodically Corrugated Interface Between an Isotropic Medium and a Gyroelectromagnetic Uniaxial Medium Gigli, Miriam Laura; Inchaussandague, Marina Elizabeth; Depine, Ricardo Angel A formulation of the Rayleigh method for modeling unidimensional periodically corrugated gyroelectromagnetic uniaxial gratings with shallow grooves is presented. The orientation of the preferred axis of the anisotropic medium is arbitrary and incidences from both media are considered. We show that the present method gives reliable results for groove height to period ratio up to 0.3. Numerical examples for sinusoidal gratings in classical and conical mountings are provided. © 2006, The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.

Modeling broadband electromagnetic induction responses of 2-D multilayered structures Martinelli, Hilda Patricia; Osella, Ana Maria; Lascano, Eugenia Dual-coil frequency-domain electromagnetic induction (EMI) systems are commonly used as detectors of buried metallic objects, but they are also increasingly used for environmental purposes such as detection of contaminant plumes and archaeological prospection. Usually, data are analyzed directly by visualizing the in-phase and quadrature components, and also by applying one-dimensional inversion methods. Besides, there exist three-dimensional (3-D) forward and inverse modeling codes based on finite-difference techniques, but these methods are not routinely applied because their computation cost for real geophysical situations is still too high. The computation cost is significantly lower for two-dimensional (2-D) structures since this problem is not 3-D but 2.5-D. Few 2.5-D methods have been published in the last years, based on finite-element techniques, but for the case of electric dipole sources. In this paper, the authors present a 2.5-D forward-modeling algorithm, based on Rayleigh-Fourier expansions, for calculating the response of 2-D multilayered earth with irregular boundaries to the magnetic-dipole sources. Using this code, the authors numerically simulated the dual-coil frequency-domain EMI response of a soil model that could be found in environmental research. They considered a buried nonmetallic object, conductive with respect to the host media, and calculated its response for different orientations of the transmitter and receiver coils. The best resolution for detecting and characterizing this object corresponded to the configuration in which the axes of the transmitter and receiver dipoles were parallel to the ground surface and perpendicular to the symmetry axis of the buried objects, and the axis of the instrument was parallel to that symmetry axis. Finally, the authors interpreted the field data from a profile exhibiting resistive anomalies, corresponding to underground contamination, by using their forward code and a trial-and-error procedure. This profile had been previously characterized through the inversion of dipole-dipole electrical data. They considered that result to select their starting multilayered model. They obtained a good correlation between the EMI data and the synthetic response of the final multilayered model. Besides, this model is consistent with the image of the electrical inversion. During the modeling process, the method showed to be practical and versatile and to have a good convergence. © 2006 IEEE.

Endogenous or exogenous coagulation factor level and the response to activated protein C Gennari, Laura C.; Blanco, Alicia Noemi; Dominguez, Maria Paula; Grosso, Silvia H.; Lazzari, María Ángela The abnormal response to activated protein C could be the mechanism to explain the prothrombotic role of elevated coagulation factor levels. We evaluated the effect of factor VIII, II, or X (FVIII, FII, or FX) levels on activated protein C resistance technique and its association with the resistant phenotype.

The biological sense of cancer: a hypothesis Ruggiero, Raul Alejandro; Bustuoabad, Oscar David Most theories about cancer proposed during the last century share a common denominator: cancer is believed to be a biological nonsense for the organism in which it originates, since cancer cells are believed to be ones evading the rules that control normal cell proliferation and differentiation. In this essay, we have challenged this interpretation on the basis that, throughout the animal kingdom, cancer seems to arise only in injured organs and tissues that display lost or diminished regenerative ability.

Amyloid-β peptide remnants in AN-1792-immunized Alzheimer's disease patients: A biochemical analysis Patton, R. Lyle; Kalback, Walter M.; Esh, Chera L.; Kokjohn, Tyler A.; Van Vickle, Gregory D.; Luehrs, Dean C.; Kuo, Yu-Min; Lopez, John; Brune, Daniel; Ferrer, Isidro; Masliah, Eliezer; Newel, Amanda J.; Beach, Thomas G.; Castaño, Eduardo Miguel; Roher, Alex E. Experiments with amyloid-β (Aβ)-42-immunized transgenic mouse models of Alzheimer's disease have revealed amyloid plaque disruption and apparent cognitive function recovery. Neuropathological examination of patients vaccinated against purified Aβ-42 (AN-1792) has demonstrated that senile plaque disruption occurred in immunized humans as well. Here, we examined tissue histology and quantified and biochemically characterized the remnant amyloid peptides in the gray and white matter and leptomeningeal/cortical vessels of two AN-1792-vaccinated patients, one of whom developed meningoencephalitis. Compact core and diffuse amyloid deposits in both vaccinated individuals were focally absent in some regions. Although parenchymal amyloid was focally disaggregated, vascular deposits were relatively preserved or even increased. Immunoassay revealed that total soluble amyloid levels were sharply elevated in vaccinated patient gray and white matter compared with Alzheimer's disease cases. Our experiments suggest that although immunization disrupted amyloid deposits, vascular capture prevented large-scale egress of Aβ peptides. Trapped, solubilized amyloid peptides may ultimately have cascading toxic effects on cerebrovascular, gray and white matter tissues. Anti-amyloid immunization may be most effective not as therapeutic or mitigating measures but as a prophylactic measure when Aβ deposition is still minimal. This may allow Aβ mobilization under conditions in which drainage and degradation of these toxic peptides is efficient.

Differential involvement of ERK1-2 and p38MAPK activation on Swiss 3T3 cell proliferation induced by prostaglandin F2alpha Dekanty, Andres; Giulianelli, Sebastian Jesus; Coso, Omar Adrian; Rudland, Phillip S.; Jimenez de Asua, Luis Adan Felipe Prostaglandin F2alpha (PGF2alpha) induces cyclin D1 expression and DNA synthesis in Swiss 3T3 cells. In order to assess which signaling mechanisms are implicated in these processes, we have used both a pharmacological approach and interfering mutants. We demonstrate that PGF2alpha induces extracellular-signal-regulated kinase (ERK1-2) and p38MAPK activation, and inhibition of any of these signaling pathways completely blocks PGF2alpha-stimulated DNA synthesis. We also show that ERK1-2, but not p38MAPK activation is required to induce cyclin D1 expression, strongly suggesting that the concerted action of cyclin D1 gene expression and other events are required to induce complete phosphorylation of retinoblastoma protein and S-phase entry in response to PGF2alpha.

Retinal dysfunction in patients with chronic Chagas’disease is associated to anti-Trypanosoma cruzi antibodies that crossreact with rhodopsin Matsumoto, Silvia C.; Labovsky, Vivian; Roncoroni, Marcela; Guida, Maria Catalina; Gimenez, Luisa; Mitelman, Jorge; Gori, Horacio; Jurgelevicius, Renata; Grillo, Alejandro; Manfredi, Pablo; Levìn, Mariano J.; Paveto, Cristina To investigate retinal involvement in chronic Chagas' disease, we performed electroretinography and retinal fluorescein angiography studies in chagasic patients. Our results demonstrated a dissociated electrophysiological response characterized by both an abnormal reduction of the electroretinographic b-wave amplitude and a delayed latency, under the dark-adaptated condition. These alterations are compatible with a selective dysfunction of the rods. Antibodies raised against Trypanosoma cruzi that also interact with beta1-adrenergic receptor blocked light stimulation of cGMP-phosphodiesterase in bovine rod membranes. The specificity from the antibody-rhodopsin interaction was confirmed by Western blot analysis and antigenic competition experiments. Our results suggest an immunomediated rhodopsin blockade. T. cruzi infection probably induces an autoimmune response against rhodopsin in the chronic phase of Chagas' disease through a molecular mimicry mechanism similar to that described previously on cardiac human beta1-adrenergic and M2-cholinergic receptors, all related to the same subfamily of G-protein-coupled receptors.

Alfa-enolasa: a novel autoantigen in patients with premature ovarian failure Sundblad, Victoria; Bussmann, Leonardo Edmundo; Chiauzzi, Violeta Alicia; Pancholy, Vijay; Charreau, Eduardo Hernan Although controversial, the presence of circulating antiovarian antibodies (AOA) may be considered a marker of autoimmune premature ovarian failure (POF). The purpose of the present work was to evaluate the presence of AOA in POF patients, and to identify a possible autoantigen in order to develop a reliable diagnostic tool that might help to determine the real prevalence of autoimmune POF.

Metodología para determinar el potencial solar de entornos de baja densidad del área metropolitana de Mendoza Arboit, Mariela Edith; Diblasi, Angela Magdalena; Mesa, Nestor Alejandro; de Rosa, Carlos El presente estudio intenta aportar conocimientos y metodologías para evaluar el acceso al recurso solar del parque edilicio urbano existente, reconociendo su complejidad y definiendo con precisión las variables significativas que definen la utilización del recurso, para los usos de calefacción de espacios (muros al norte) y calentamiento de agua para uso doméstico (techos horizontales y proyección horizontal de techos con pendiente). El objetivo del mismo es aplicar un modelo estadístico de regresión lineal múltiple que permita estudiar la correlación existente entre el potencial solar del parque edilicio urbano actual (variable respuesta), y un conjunto de variables explicativas, urbanas y edilicias: forma y orientación de las manzanas, ancho de los cañones urbanos, incidencia del arbolado, morfología edilicia, áreas de parcelas, ocupación del suelo y densidad edilicia. Se propone desarrollar una metodología que permita cuantificar el potencial de la edilicia del Área Metropolitana de Mendoza (AMM), y elaborar lineamientos de diseño apropiados para formular e implementar una legislación que establezca rangos de valores para cada variable significativa, tendiente al aprovechamiento pleno del recurso solar en la ciudad, y por lo tanto al desarrollo ambiental y energéticamente sustentable.; The present study aims at contributing knowledge and methodology to assess the access to the solar resource of the existing urban building stock, a knewedging its complexity and precisely defining the utilization of the resources, for the uses of space heating (north facing walls) and domestic water heating ( horizontal roofs and horizontal projection of tilted roofs). The objective of the study is to utilize a statistical multiple linear regression model that would allow to define the correlations between the solar potential of the present building stock (variable response) and a set of urban and building explanatory variables: form and orientation of city blocks, urban canyon width, urban forest incidence, building morphology, parcel dimensions, soil occupation and building density. It is expected that the results of the study will allow to quantify the solar potential of the present building stock in MMA and elaborate suitable design guidelines for the elaboration and implementation of norms that would establish value ranges for each significant variable, aiming at the maximum utilization of the solar resource in the city, as a significant contribution to its environmental and energy sustainable development

Comparación de métodos de lisis y extracción de ADN de trofozoiteos de Giardia lamblia; Comparison of lysis methods and DNA extraction of Giardia lamblia trophozoites Molina, Nora Beatriz; Polverino, Daniela; Minvielle, Marta Cecilia; Apezteguía, María; Aguilar, Orlando Mario; Basualdo, Juan A. The efficiency of lysis procedures and DNA purification treatments of Giardia lamblia trophozoites were evaluated regarding the breaking-up efficiency, quantity and pureness of DNA, processing time and costs. Five lysis methods (distilled water and heating; distilled water, heating and proteinase K; buffer D Lysis; buffer E lysis, and commercial kit), and three DNA purification methods (phenol:chloroform:isoamilic, Chelex 100 and commercial kit) were tested. The obtained data were statistically analyzed. The buffer E lysis and Chelex combination was simple and economic method which produced high DNA performance with low pureness. Commercial kit was simple and expensive method which generated low yields of DNA with appropriate purity level for molecular analysis.; Se evaluó la eficiencia de procedimientos de lisis y tratamientos de extracción de ADN de trofozoítos de Giardia lamblia respecto a la eficiencia de ruptura, cantidad y pureza de ADN, además de los tiempos de procesamiento y costos. Se testearon cinco métodos de lisis (agua destilada y calor; agua destilada, calor y proteinasa K; buffer de lisis D; buffer de lisis E y un kit comercial) y tres métodos de purificación de ADN (fenol:cloroformo: isoamílico; Chelex 100 y un kit comercial). Los datos obtenidos se analizaron estadísticamente. La combinación de buffer de lisis E y Chelex fue un método simple y económico, que produjo alto rendimiento de ADN con baja pureza. Ella técnica comercial fue un método simple, más costoso que produjo bajas cantidades de ADN con un nivel de pureza apropiado para estudios moleculares.

The equilibrium limit of the Casati-Prosen model Castagnino, Mario Alberto G. J. An alternative explanation of the decoherence in the Casati–Prosen model is presented. It is based on the self-induced decoherence formalism extended to non-integrable systems.

Description of Maunder-like events from a stochastic Alpha–Omega model Gomez, Daniel Osvaldo; Mininni, Pablo Daniel One of the most impressive solar phenomena is its magnetic activity cycle. The number of sunspots observed in the solar surface varies with a period of approximately 11 years. Superimposed to this cyclic behavior, there are sporadic events such as the Maunder minimum, during which very few sunspots were detected. In the present work, an Alpha–Omega dynamo model is proposed to study these phenomena. We use velocity profiles of the solar interior obtained from helioseismology, which include differential rotation (the X-effect), a meridional flow and the turbulent velocity field of the convective region (the a-effect). By simulating the helicoidal and disordered flow of the giant cells through a stochastic component in the a coefficient, we reproduce not only the periodic behavior of the solar cycle, but also sporadic events such as the Maunder minimum. This model suggests the existence of a link between giant cell fluctuations and the irregularities observed in the solar cycle, such as north–south asymmetries and secular variations like the Maunder minimum.

Redescription of Excirolana armata (Dana, 1853) and synonymy of Cirolana argentina Giambiagi, 1930 (Crustacea: Isopoda: Cirolanidae) Ribetti, Virginia L.; Roccatagliata, Daniel Carlos Excirolana armata (Dana, 1853) is redescribed on the basis of material collected from Puerto Quequén, Argentina, the type locality of Cirolana argentina Giambiagi, 1930. Based on this material, it is concluded that C. argentina is a junior synonym of E. armata. The distribution of E. armata is extended from Rio de Janeiro to Golfo San José (northern Patagonia). Excirolana armata is most similar to the Chilean species Excirolana hirsuticauda Menzies, 1962 and Excirolana monodi Carvacho, 1977; a table comparing these three species is provided. The male second pleopod and pleotelson of E. hirsuticauda are illustrated.

Photophysics of anthracene–indole systems in unilamellar vesicles of DMPC and POPC: Exciplex formation and temperature effects Novaira, Ana Ines; Previtali, Carlos Mario The quenching of anthracene fluorescence by indole (IN), 1,2-dimethylindole (DMI), tryptophan (Trp) and indole 3-acetic acid (IAA) in dimiristoylphophatidylcholine (DMPC) and palmitoyloleoylphosphatidylcholine (POPC) lipid bilayers was investigated. The studies were carried out at 25 ºC in POPC vesicles and below (15 C) and above (35 C) the phase transition temperature (24 ºC) of DMPC. A very efficient quenching of the anthracene fluorescence by IN and DMI in the lipid membrane is observed in all cases. It is less efficient in the case of Trp and IAA. Stern–Volmer plots are linear for DMI but present a downward curvature for the other quenchers. This was interpreted as an indication of the presence of an inaccessible fraction of anthracene molecules. By a modified Stern–Volmer analysis the fraction accessible to the quenchers and the quenching constant were determined. Partition constants of the quenchers were obtained from the changes in the fluorescence emission of the indole moiety caused by the presence of the phospholipid. Using the partition constants bimolecular quenching rate constants were determined in terms of the local concentration of quencher in the lipid bilayer. These corrected rate constants are lower than those in homogeneous solvents. In the case of DMPC values the gel phase are higher than in the liquid-crystalline phase. In the quenching by IN and DMI a new, red shifted, emission band appears which could be assigned to an exciplex emission. The exciplex band is absent in the quenching by IAA and Trp.

Impact on growth and aflatoxin B1 accumulation by Kluyveromyces isolates at different water activity conditions La Penna, Mariángeles; Etcheverry, Miriam Graciela This study showed the impact on germination, mycelial growth and aflatoxin B1 accumulation when interacting Aspergillus aflatoxigenic strains with Kluyveromyces isolates and the effect of water activity on this relationship. Isolates Y14 and Y16 reduced the percentage of germination of all Aspergillus strains and decrease germ tube elongation rate at majority of water activity assayed. Similarly they produced an increase of germination lag phase and lag phase of growth beside decreased growth rate of all Aspergillus strains. At water activities 0.994, 0.982, 0.955 and 0.937, no aflatoxins were produced in paired cultures with isolates Y25, Y22, Y16, and Y14, and Kluyveromyces isolates Y14 and Y16 impact both growth and aflatoxin accumulation at wide range of water activity.

Monte Carlo simulation of metal deposition on foreign substrates Giménez, María Cecilia; Ramirez Pastor, Antonio Jose; Leiva, Ezequiel Pedro M. The deposition of a metal on a foreign substrate is studied by means of grand canonical Monte Carlo simulations and a lattice-gas model with pair potential interactions between nearest neighbors. The influence of temperature and surface defects on adsorption isotherms and differential heat of adsorption is considered. The general trends can be explained in terms of the relative interactions between adsorbate atoms and substrate atoms. The systems Ag/Au(1 0 0), Ag/Pt(1 0 0), Au/Ag(1 0 0) and Pt/Ag(1 0 0) are analyzed as examples.