A multicoincidence study of ionic fragmentation of methyl tiocyanate, CH3SCN involving S 2p electrons Cortés, E.; Erben, Mauricio Federico; Gerones, Mariana; Romano, Rosana Mariel; Della Vedova, Carlos Omar We report a study of the photon impact excitation and dissociation dynamics of CH3SCN exited at the S 2p level by using synchrotron radiation. Within our knowledge ionic fragmentation of photon excited CH3SCN has not been previously described. The transitions observed in the TIY spectrum around the S 2p edge shows an excellent agreement with the optical oscillator strengths derived from electron energy loss spectra recorded under electric dipole dominated conditions.3SCN exited at the S 2p level by using synchrotron radiation. Within our knowledge ionic fragmentation of photon excited CH3SCN has not been previously described. The transitions observed in the TIY spectrum around the S 2p edge shows an excellent agreement with the optical oscillator strengths derived from electron energy loss spectra recorded under electric dipole dominated conditions.

Intensity ratios of H lines: Departures from the ideal conditions in the range of laser-induced breakdown spectroscopy experiments Cruzado, Alicia; Di Rocco, Hector Omar In the present paper we analyze the behavior of H line intensity ratios with electron density and electron temperature in intermediate-density plasmas. We analyze the influence on the line intensity ratios of (1) the departures from local thermodynamic equilibrium (LTE) of the level population ratios, (2) the plasma opacity, and (3) the lowering of the ionization potential. We look, particularly, at the lines Hα, Hβ, Hγ, and Hδ and the energy levels involved in the corresponding atomic transitions for their use as diagnostics in laser-induced breakdown spectroscopy (LIBS) experiments. One important conclusion is that, for typical values of the plasma dimension and the electron temperature taking place in LIBS, i.e., L = 1 mm and Te = 10 000 K, respectively, the intensity ratios Hβ/Hα, Hγ/Hα and Hδ/Hα depart from the ideal values by less than 10% in the interval 0.65 × 1014 part/cm3 ≤ NHI ≤ 3.6 × 1017 part/cm3, which means 1 × 1014 part/cm3 ≤ Ne, ≤ 1 × 10 16 part/cm3 for a gas of pure hydrogen. For higher densities, the departures from ideal conditions increase very quickly due to opacity effects.

Apoptosis y autofagia en las células estrelladas: Un nuevo potencial de los tocotrienoles en reducir la fibrogénesis asociada a la pancreatitis crónica Ropolo, Alejandro Javier; Vaccaro, Maria Ines Objetivo: la eliminación selectiva de células estrelladas pancreáticas (PSC) activadas a través de la inducción de su propia muerte programada es un objetivo de interés terapéutico en pacientes con pancreatitis crónica. En este trabajo se investigaron los efectos de los tocotrienoles sobre la muerte de PSC activadas. Materiales y métodos: PSC activadas y quiescentes, y células acinaresde páncreas de rata fueron tratadas con diferentes derivados de la vitamina E, α-tocoferol, α-, β-, γ- y δ-tocotrienoles, y una fracción rica en tocotrienoles de aceite de palma. Resultados: la fracción rica en tocotrienoles (TRF), pero no α-tocoferol, redujo la viabilidad de PSC activadas mediante el establecimiento de un programa de muerte, independiente de la regulación del ciclo celular. Las PSC activadas murieron por apoptosis, como fue indicado por un incremento en lafragmentación de ADN y la activación de caspasas, y a través de autofagia, como demostró la formación de vacuolas autofágicas y la acumulación de LC3-II. En contraste con los α-tocoferoles, la TRF causó una intensa y sostenida despolarización de la membrana mitocondrial y una gran liberación de citocromo c. La inhibición de caspasas con zVAD-fmk suprimió la apoptosis inducida por tocotrienoles pero amplificó la autofagia. Sin embargo, el bloqueo del poro de transición de permeabilidad mitocondrial con ciclosporina A abolió completamente los efectos letales de los tocotrienoles sobre las PSC. La inducción de muerte por tocotrienoles fue restringida a las PSC activadas, ya que no causó apoptosis ni en las PSC quiescentes ni en las células acinares. Conclusiones: los tocotrienoles gatillan selectivamente la muerte de PSC activadas actuando sobre el poro de transición de permeabilidad mitocondrial.Los hallazgos revelan un nuevo potencial para los tocotrienoles en reducir la fibrogénesis asociada a la pancreatitis crónica.

Estudio electroquímico del Ácido 3,4-Dihidroxifenilacético (DOPAC) adsorbido sobre oro; Electrochemical study of 3,4-Dihydroxyphenylacetic Acid (DOPAC) adsorbed on gold Esquenoni, Sylvia Matilde; Von Mengershausen, Alicia Elena; Sustersic, Maria Gisela El objetivo de este estudio es conocer el comportamiento del ácido 3,4 dihidroxifenilacético (DOPAC) como adsorbato y como reactivo electroquímico adsorbido sobre oro. Las características de la reacción redox del anillo catecol permite estudiar esta sustancia adsorbida a circuito abierto. El procedimiento consiste en las etapas de adsorción, enjuague con el electrolito y barridos de voltametría cíclica para determinar la cantidad de sustancia adsorbida y el comportamiento electroquímico de la misma. Se trabajó con dos celdas, una de adsorción y otra electroquímica, termostatizadas a 25°C. La adsorción del DOPAC es débil, consolidándose el enlace con el tiempo para formar una ligadura tipo σ. Se determina un área por molécula de 47 Å2, similar a la obtenida para la dopamina.; The objective of this study was to obtain knowledge on the behavior of acid 3,4 dihydroxyphenylacetic (DOPAC) as an adsorbate and electrochemical reagent adsorbed on gold. The redox reaction characteristic of the catechol ring allows the study of the substance adsorption under open circuit conditions. The step of the procedure include adsorption, rinsing with electrolyte, and making cyclic voltammetric scan to determine the amount of adsorbed substance and its electrochemical behavior. For this, two cells were employed, one for adsorption, and the other electrochemical, both were thermostatted at 25°C. The DOPAC adsorption is weak. The adsorption bound is strengthening with the time forming a σ bound. The area per molecule of 47 Å2 , very near of that of the dopamine is obtained.

Relaciones potenciodinámicas corriente/potencial para la formación electroquímica de capas yuxtapuestas; Potentiodynamic current/potential relationships for electrochemical formation of yuxtaposed layers Moreno, Dora Elia; Sustersic, Maria Gisela El objetivo de este trabajo es analizar y comparar las distintas propuestas teóricas presentadas para la formación electroquímica de monocapas y capas yuxtapuestas. Se estudia la variación del grado de cubrimiento de la superficie del electrodo en función del tiempo en la electroadsorción para procesos reversibles. El modelo básico considerado es el de Sirinivasan-Gileadi. Este ha sido ampliado por acoplamiento de un proceso de disolución química y por la participación de una resistencia óhmica. Recientemente se ha elaborado un modelo de formación de multicapas, aplicando las ecuaciones de Srinivasan-Gileadi a cada una de ellas, teniendo en cuenta la resistencia ohmica que cada capa opone al paso de corriente. Se analiza, además de la ley de cubrimiento superficial, el comportamiento de la relación corriente/potencial en los casos de monocapas y capas yuxtapuestas con o sin resistencia óhmica, mostrándose su influencia en el potencial del máximo.; The objective of this work is to analyze and to compare different models for electrochemical formation of mono and yuxtaposed-layer. In particular, the variation of electrode surface coverage as a function of time is studied for electro-adsorption in reversible reactions. The basic model is that of SrinivasanGileadi. This has been extended by coupling a chemical dissolution process and an ohmic resistance. A model for multi-layers formation elaborated taking into account the Srinivasan-Gileadi model for each of them and considering the ohmic resistance that each layer opposes to the electrical current has also been analyzed. Besides the surface coverage law, the behavior of the current/potential relation in the cases of mono and yuxtaposed-layers with and without ohmic resistance are considered. The influence of these variables in the peak potential is shown.

Regional geoid determination in Tierra del Fuego including GPS levelling del Cogliano, Daniel Hector; Dietrich, R.; Richter, Andreas Jorg; Perdomo, Raul Anibal; Hormaechea, José Luis; Liebsch, G.; Fritsche, M. A regional geoid model for the Argentine part of the Isla Grande de Tierra del Fuego, established in previous works on the basis of GPS levelling, suffers a lack of observation data in the remote south-western investigation area. In order to improve the data distribution in this region, the mean lake level of Lago Fagnano has been regarded as a natural indicator for the local geoid. Using a GPS buoy and pressure tide gauges, a method to determine the mean lake surface topography with respect to the ellipsoid has been developed. It is shown thatthe obtained lake level geometry is essentially controlled by the regional gravity field. The derived information on the mean lake level has been included in the geoid model, which results in a more detailed and plausible representation of the regional geoid.

El efecto ansiolítico de testosterona en ratas macho no se debe a la aromatización de estrógeno: evidencias preliminares Yunes, Roberto Miguel Federico; Boulin F.; Cabrera Kreiker, Ricardo Jorge Se sabe que testosterona (T) y sus metabolitos dihidrotestosterona y 3œandrostanediol presentan propiedades ansiolíticas en modelos animales de ansiedad. Sin embargo, y dado que T puede ser aromatizada a estradiol (E2), no se puede descartar un rol ansiolítico de este último compuesto orgánico. En este trabajo, mediante la utilización de ratas macho intactas y castradas, y empleando T o E2 como terapia de reemplazo, pudimos comprobar que E2 no posee efectos ansiolíticos, en tanto sí están presentes posterior a la impregnación con T o eventualmente con sus metabolitos no aromatizables; It has been reported that testosterone (T) and its metabolites dihydrotestosterone and 3œ-androstanediol exhibit anxiolytic properties. However, and since T is also usually aromatized to estradiol (E2), it has not been ruled out the possibility of E2 being responsible for the aforementioned effect, at least partially. In this report, by using intact and castrated male rats, with or without E2 or T replacement, we could conclude that the anxiolytic effect is not due to E2 but to T and, eventually its non aromatizable metabolites.

In Vivo Crosslinking Methods for Analyzing the Assembly and Architecture of Chemoreceptor Arrays Studdert, Claudia Alicia; Parkinson, John S. The chemoreceptor molecules that mediate chemotactic responses in bacteria and archaea are physically clustered and operate as highly cooperative arrays. Few experimental approaches are able to investigate the structure-function organization of these chemoreceptor networks in living cells. This chapter describes chemical crosslinking methods that can be applied under normal physiological conditions to explore physical interactions between chemoreceptors and their underlying genetic and structural basis. Most of these crosslinking approaches are based on available atomic structures for chemoreceptor homodimers, the fundamental building block for higher-order networks. However, the general logic of our in vivo crosslinking approaches is readily applicable to other protein-protein interactions and other organisms, even when high-resolution structural information is not available.

A new species of Uristes Dana, 1849 (Amphipoda: Lysianassoidea: Uristidae) from the Beagle Channel, Argentina Chiesa, Ignacio Luis; Alonso, Gloria Maria A new species of Uristes Dana, 1849 (Uristidae) collected from shallow waters in the Beagle Channel, Argentina, is described and illustrated. Uristes yamana n. sp., the third species of this genus reported for the Magellan area, is closely related to U. serratus Schellenberg 1931, principally by the possession of an unusual stout gnathopod 1 propodus. Both species can be separated by telson shape and relative setosity of uropod 3. The geographical distribution of U. gigas Dana 1849 is also emended.

Pobreza y salud en la Argentina: descripción de una relación asimétrica en base a la Encuesta de Condiciones de Vida del año 2001 Bergesio, Liliana del Carmen; Golovanevsky, Laura Andrea El trabajo muestra la inequidad en cuestiones de salud en la República Argentina, a partir de la comparación de regiones geográficas. Para ello se realiza un análisis de la relación entre conductas vinculadas a la salud y pobreza de los hogares, en base a microdatos de la Encuesta de Condiciones de Vida del año 2001 (ECV-2001). Se concluye que la relación entre pobreza y salud tiene una variedad de aspectos y connotaciones que la tornan muy compleja, presentándose los efectos de la pobreza sobre las condiciones de salud de niños, mujeres y dificultades de accesibilidad como los más relevantes. Para la Argentina, el principal problema es que los servicios y la cobertura de la salud pública son deficitarios y fuertemente inequitativos, desatendiendo a los más pobres (sean estos individuos o regiones).; The work shows the inequity in health issues in the Argentine Republic, based on the comparison of geographical regions. To do this, an analysis of the relationship between behaviors related to health and poverty in households is carried out, based on microdata from the 2001 Survey of Living Conditions (ECV-2001). It is concluded that the relationship between poverty and health has a variety of aspects and connotations that make it very complex, presenting the effects of poverty on the health conditions of children, women and accessibility difficulties as the most relevant. For Argentina, the main problem is that public health services and coverage are deficient and strongly inequitable, neglecting the poorest (be they individuals or regions).

Análisis paleoambiental sobre la base del estudio malacológico del sitio Paso Otero 1 (región pampeana, Argentina); Paleoenvironmental Analysis of the Malacological Studies Conducted at paso Otero 1 Site (Pampean Region, Argentina) Steffan, Pamela Guillermina Se infieren las condiciones paleoclimáticas y paleoambientales en Paso Otero 1 durante el Holoceno, particularmente desde los ca. 4800 AP a 2900 años AP. Paso Otero 1 está ubicado en el área del curso medio del río Quequén Grande (área Interserrana Bonaerense, región pampeana). El análisis de la composición de la fauna de gasterópodos comprende distintos aspectos: diversidad de especies representadas en el muestreo, medidas de abundancia relativa de individuos por especie y distribución de frecuencias por niveles muestreados. Los resultados indican una mayor humedad hacia los 4800 años AP y un ascenso en la temperatura hacia los 2900 años AP. Estos análisis permitieron evaluar la información paleoambiental de los gasterópodos fósiles y aportar datos acerca de las condiciones ambientales locales.; In this paper, paleoclimatic and paleoenvironmental conditions at Paso Otero 1 are inferred for the Holocene, particularly from ca. 4800 to 2900 BP. Paso Otero 1 is located in the area of the middle basin of the Quequén Grande river (Interserrana Bonaerense area, Pampean region). Analysis of the faunal composition of gastropod fauna included different aspects: diversity of represented species in the sample, measurements of relative abundance of individuals by species, and the distribution of frequencies for sampled levels. The results indicate greater humidity toward ca. 4800 BP and an increase in temperature toward 2900 BP. The analyses enable the environmental information of the fossil gastropods to be evaluated, contributing data on local environmental conditions.

Explosion time in stochastic differential equations with small diffusion Groisman, Pablo Jose; Rossi, Julio Daniel We consider solutions of a one dimensional stochastic differential equations that explode in finite time. We prove that, under suitable hypotheses, the explosion time converges almost surely to the one of the ODE governed by the drift term when the diffusion coefficient approaches zero.

The best Sobolev trace constant in a domain with oscillating boundary Fernandez Bonder, Julian; Orive, Rafael; Rossi, Julio Daniel In this paper we study homogenization problems for the best constant for the Sobolev trace embedding W1, p (Ω) {right arrow, hooked} Lq (∂ Ω) in a bounded smooth domain when the boundary is perturbed by adding an oscillation. We find that there exists a critical size of the amplitude of the oscillations for which the limit problem has a weight on the boundary. For sizes larger than critical the best trace constant goes to zero and for sizes smaller than critical it converges to the best constant in the domain without perturbations.

On the embedding problem for 2+s4 representations Pacetti, Ariel Martín Let 2+S4 denote the double cover of S4 corresponding to the element in H2(S4, Z/2Z) where transpositions lift to elements of order 2 and the product of two disjoint transpositions to elements of order 4. Given an elliptic curve E, let E[2] denote its 2-torsion points. Under some conditions on E elements in H1(GalQ, E[2])\{0} correspond to Galois extensions N of Q with Galois group (isomorphic to) S4. In this work we give an interpretation of the addition law on such fields, and prove that the obstruction for N having a Galois extension N˜ with Gal(N/˜ Q) 2+S4 gives a homomorphism s+ 4 : H1(GalQ, E[2]) → H2(GalQ, Z/2Z). As a corollary we can prove (if E has conductor divisible by few primes and high rank) the existence of 2-dimensional representations of the absolute Galois group of Q attached to E and use them in some examples to construct 3/2 modular forms mapping via the Shimura map to (the modular form of weight 2 attached to) E.

Los Salesianos y la conquista de la Patagonia: desde Don Bosco hasta sus primeros textos escolares e historias oficiales; The Salesians and the Conquest of the Patagonia: From Don Bosco to their first school texts and official history records Nicoletti, Maria Andrea La Congregación Salesiana de Don Bosco llegó a la Argentina en 1875 con la intención de evangelizar “infieles” en la Patagonia, mediante un plan concreto de adoctrinamiento y educación para los pueblos originarios. Para ello, Don Bosco formuló un proyecto en el que el daba cuenta acerca de la situación violenta entre los indígenas y el Estado argentino en Patagonia. Tras algunos intentos fallidos de ingresar a la Patagonia, los Salesianos acompañan al ejército de Julio Roca en 1879. Este suceso fue narrado por los primeros misioneros como un hecho cruel y violento perpetrado por el ejército, al que criticaron fuertemente, narrando la situación de marginalidad, pobreza y exclusión de los sobrevivientes. Sin embargo, justificaron esta acción en función de la “acción civilizadora” del Estado y la “necesidad” de cristianización de sus habitantes. Estas primeras fuentes se fueron reinterpretando en distintos textos salesianos: desde los informes internos (Anales) hasta sus propios los textos escolares y sus narraciones históricas. Cada fuente seleccionó y justificó esta información de primera mano de acuerdo al lector, el contexto historiográfico y a su propia reelaboración sobre este tema clave: la violencia y la evangelización.; The Salesian Congregation of Don Bosco arrived in Argentina in 1875 with the aim of evangelizing “infidels” in the Patagonia with a specific plan of indoctrination and education for the originary people. For this purpose, Don Bosco formulated a project where he stated the violent situation between the indigens and the Argentinean state in Patagonia. After some unsuccessful attempts of entering the Patagonia, the Salesians went along with the army of Julio Roca in 1879. This event was narrated by the first missioners as a cruel and violent action perpetrated by the army, which they criticized heavily, telling about the situation of marginality, poverty and exclusion of the survivors. However, they justified this action according to the “civilizing action” of the State and the “necessity” of Christianization of its inhabitants. These first sources have been reinterpreted in different Salesian texts: from the internal reports (Annals) to their own school texts and historical narrations. Each source selected and justified this first-hand information according to the reader, the historiographical context and their own re-elaboration of this key subject: violence and evangelization.

Hb Alesha [β67(E11)Val→Met, GTG→ATG] in an Argentinean girl Eberle, Silvia Eandi; Noguera, Nelida Ines; Sciuccati, Gabriela; Bonduel, Mariana; Díaz, Lilian; Staciuk, Raquel; Targovnik, Hector Manuel; Feliu Torres, Aurora Hb Alesha is caused by a GTG>ATG mutation at codon 67 of the b-globin gene, resulting in abnormal beta-globin chains in which the normal beta67(E11) valine is changed to methionine. This hemoglobin (Hb) is also known as Hb Bristol, the first unstable Hb described, since in a fraction of the variant the methionine is modified into an aspartic acid by a posttranslational modification. This replacement disrupts the apolar bonds between the valine and the heme group, producing an unstable Hb and severe hemolysis. We have identified this rare hemoglobinopathy in an Argentinean girl with severe hemolytic anemia, splenomegaly and frequent requirement for red blood cell transfusions.

Rafael Bielsa y la conformación de un nuevo modelo de formación científica universitaria de Marco, Miguel Angel L. El presente artículo se enmarca en el abordaje biográfico del doctor Rafael Bielsa efectuado en el marco del Proyecto "Juristas, Derecho y Sociedad en la Argentina contemporánea. Ideas y mentalidades de los operadores jurídicos (1901-1970)", del Instituto de Investigaciones en Historia del Derecho. Siguiendo un camino abierto por el doctor Víctor Tao Anzoátegui en la década del 70, se profundiza en la obra de Rafael Bielsa en su prédica por la superación del positivismo, el fomento de los estudios jurídicos y sus iniciativas en reformar el sistema jurídico. Analiza la influencia de lo regional en la visión de Bielsa y sus propuestas superadoras de la Reforma Universitaria, poniendo a la luz el valioso contenido de las actas del Consejo Directivo de la Facultad de Ciencias Económicas, Comerciales y Políticas y del Colegio de Abogados de Rosario. La primera parte se refiere a la incidencia de la Facultad de Ciencias Económicas, Comerciales y Política en la formación de recursos para la región; la segunda, al decanato de Rafael Bielsa y la proyección internacional de la Facultad; la tercera, a la situación en tiempos de intervenciones nacionales y el Golpe de Estado de 1930; la cuarta parte: al breve rectorado de Bielsa al frente de la Universidad Nacional del Litoral y su tercer decanato; la quinta parte: a la consolidación de los flamantes institutos de investigación; y la sexta parte, al cuarto decanato de Bielsa, coincidente con el inicio de la década del 40. El relevamiento de actas concluye en 1943, cuando un nuevo golpe de Estado implicó un cambio de rumbo en la política universitaria argentina.

Infection by Rickettsia bellii and Candidatus "Rickettsia amblyommii" in Amblyomma neumanni ticks from Argentina Labruna, Marcelo B.; Pacheco, Richard C.; Nava, Santiago; Brandão, Paulo E.; Richtzenhain, Leonardo J.; Guglielmone, Alberto Alejandro The tick species, Amblyomma neumanni (Acari: Ixodidae) is the most frequent tick parasitizing humans in northwestern Argentina. The present study evaluated the rickettsial infection among 55 A. neumanni adult free-living ticks collected in Dean Funes, Córdoba Province. Ticks were individually processed by the hemolymph test with Gimenez staining, isolation of rickettsia in Vero cell culture by the shell vial technique, and polymerase chain reaction (PCR) targeting the citrate synthase rickettsial gene. Through the shell vial technique, rickettsiae were successfully isolated and established in Vero cell culture from two ticks (ticks 4 and 13), which previously showed to contain Rickettsia-like organisms by the hemolymph test. These two Rickettsia isolates were designated as An4 and An13. Molecular characterization (partial DNA sequences of two to three rickettsial genes were determined) of these two isolates and phylogenetic analyses identified them as Rickettsia bellii (isolate An4) and Candidatus "Rickettsia amblyommii" (isolate An13). After testing all A. neumanni ticks by PCR, the prevalence of Candidatus R. amblyommii and R. bellii was 23.6% (13/55) and 3.6% (2/55), respectively. These two rickettsiae have been considered of unknown pathogenicity and appropriate studies to test their pathogenicity to humans or animals need to be conducted. This is the first report of Rickettsia in ticks from Argentina, and also in the species A. neumanni. The results reinforce previous findings that R. bellii (and probably Candidatus R. amblyommii) are widespread among some Neotropical Amblyomma species, suggesting that these ticks gained these bacterial agents from a common ancestor and/or by recent horizontal transmission of rickettsiae between ticks.

Phosphorous amount in floating and rooted macrophytes growing in wetlands from the Middle Paraná River floodplain (Argentina) Hadad, Hernán Ricardo; Maine, Maria Alejandra Biomass, P concentration, P amount and chlorophyll in three floating and three rooted macrophytes growing in wetlands of the Middle Paraná River floodplain measured in winter and summer were compared. Macrophytes were sampled three times in summer and twice in winter, in the period 2002/2004. Although Pistia stratiotes was the species with the highest P concentration in leaves and roots, Typha domingensis, Eichhornia crassipes and Pontederia cordata were the most efficient species in P retention in natural wetlands because of their higher biomass. Total P amount in rooted species did not show seasonal variations. However, T. domingensis accumulated a greater P amount in its aerial part in summer, whereas in winter it did so in its below-ground parts, indicating an important P dynamic regarding translocation within the plant. In summer, floating species were able to accumulate great quantities of P in a short period due to their high growth rate. In order to optimize and maintain the efficiency of constructed wetlands for P removal throughout the year, a selection of floating and rooted species should be used.

Effects of enzymatic treatment on cellulosic fibres from recycled paper. Analysis of the experimental design Taleb, María Claudia; Maximino, Mirta Graciela An enzymatic preparation consisting of cellulases and hemicellulases significantly affected the drainability and strength properties of an unbleached softwood Kraft pulp repulped in laboratory. The independent variables, treatment time and enzyme dose, were analysed using a central composite design for both the whole pulp and its fibrous fractions. Statistical analysis showed significant improvements in drainability. The effects of enzymatic treatments on strength properties were: increase in tensile index and apparent density and decrease in tear index and light scattering coefficients. Changes in fibre surfaces (initial and with enzyme treatment) could be observed by Simons´ differential stain.