Palynological zonation of the Lajas Formation (Middle Jurassic) of the Neuquén Basin, Argentina; Zonación palonológica de la Formación Lajas (Jurásico Medio), Cuenca Neuquina Martinez, Marcelo Adrian En este trabajo es presentada una nueva zonación palinológica para el Jurásico Medio del sector sur de la Cuenca Neuquina, con dos zonas y ocho subzonas creadas en base a esporomorfos y microplanton asociado, con un rango de edad que abarca desde el Aaleniano tardío hasta el Caloviano temprano. La zonación es correlacionada con zonaciones palinológicas previas de la mencionada cuenca. Se menciona el contenido macropaleontológico (principalmente amonites) y micropaleontológico (frecuencias relativas de taxones y grupos supragenéricos); A new palynological zonation for the Middle Jurassic of the southern part of the Neuquén Basin is presented. Two zones and eight subzones based on sporomorphs and associated microplankton of late Aalenian to early Callovian age are defined. These zones are correlated with previous palynological zonations in the Neuquén Basin. The macropaleontologic (mainly ammonites) and micropaleontologic content (relative frequencies of taxa and suprageneric groups) of each depositional sequence previously identified in the study area by other workers are given

Estimation of the plain high-cycle fatigue propagation resistance in steels Chapetti, Mirco Daniel In this work a method to estimate the high cyclic fatigue propagation life of steel specimens under constant loading is presented. This method is based in experimental evidence that the fatigue limit represents the threshold stress for the propagation of nucleated cracks, so that both the fatigue limit and the fatigue resistance depend on the effective resistance of the microstructural barriers that have to be overcome by the nucleated cracks. It is proposed also, that in those cases where the number of cycles that is necessary for the nucleation of the cracks can be neglected, the fatigue crack propagation life can be taken as an estimation of the total fatigue life. The high cycle fatigue propagation life of a structural steel of the type JIS 10C is estimated.

Brief commentary Schattner, Mirta Ana; Lazzari, María Ángela Recently, Tibbles et al. [1] reported that thrombopoietin (TPO) was capable of inducing P-selectin expression independently of calcium movements or platelet aggregation. They also found that leukocyte– platelet aggregates occurred after TPO cell stimulation most probably mediated by P-selection expression. Although they stated that they described a novel role for TPO in platelet function and platelet–leukocyte interactions both activities have been previously described by severalgroups [2–6]. Most of the studies showed that although TPO was not able to induce platelet activation alone it synergized platelet responses, including P-selectin expression, triggered by different agonists.

Reforma a la gestión educativa e identidad profesional de los docentes en Argentina: Estudio de un caso; Educational management reform and professional teacher identity in Argentina: A case study Freytes Frey, Ada Cora Dentro de la reforma educativa argentina, el 3° ciclo de la Educación General Básica (EGB) constituye un aspecto central, ya que plantea importantes quiebres con respecto a la estructura anterior. Este ciclo está integrado por los antiguos 7° grado de la escuela primaria y 1° y 2° año de la secundaria, por lo que implica la convivencia de dos culturas profesionales diferentes: la de los maestros y la de los profesores. A esto se suma la reformulación del rol docente que impulsa la reforma. En este trabajo, se analiza la incidencia de estos procesos en la constitución de la identidad profesional de los docentes del 3° ciclo en la provincia de Buenos Aires. Esto supone una indagación en diversos planos: a) las interpelaciones acerca de la identidad docente presentes en los discursos y lineamientos acerca de la implementación del 3º ciclo de la EGB en dicha provincia; b) los significados y representaciones identitarias que se van constituyendo en las interacciones cotidianas en las escuelas; c) las maneras en que son recibidas y procesadas estas interpelaciones y representaciones por los docentes del 3º ciclo, en un trabajo interpretativo que supone también resistencias y reformulaciones. Este planteo supone un contrapunto entre lo macro -abordado a través del análisis de contenido de ciertos discursos públicos- y lo micro -examinado a través de un estudio de casos múltiples en diversas escuelas bonaerenses-.; Within Argentine educational reform, the 3rd stage of General Basic Education (EGB) is a central aspect, since it involves important differences with regard to the former educative system structure. This stage is composed by the former primary school 7th grade and secondary school 1st and 2nd year. Therefore, it involves the daily interaction of two distinct professional cultures: that of primary and secondary school teachers. In addition, the reform policy promotes a redefinition of teachers’ roles. The paper analyses the impact of this process on the construction of 3rd stage teachers’ professional identity in the Argentine Buenos Aires province. It encompasses different levels of research: a) the interpellations about teaches’ identity found in discourses and political measures regarding the 3rd stage implementation; b) the meanings and representations as to identity constructed during daily interactions in schools; c) the diverse ways these interpellations and representations are received, interpreted and processed by 3rd stage teachers. This approach attempts to explore the macro level through content analysis of public discourses and the micro level through a multiple case study in schools. It also attempts to relate both levels.

Androgen receptors in human melanoma cell lines IIB-MEL-LES and IIB-MEL-IAN and in human melanoma metastases Morvillo, V.; Luthy, Isabel Alicia; Bravo, A. I.; Capurro, M. I.; Portela, P.; Calandra, Ricardo Saul; Mordoh, Jose The presence and characteristics of androgen receptors (AR) have been des­cribed by our group in one human melanoma cell line. We now investigated their presence in two other human melanoma cell lines, IIB-MEL-LES and IIB-MEL-IAN, as well as in biopsies of human metastatic melanoma. Scatchard analysis revealed a single binding component for both cell lines, the apparent dissociation constant obtained being 15 nM, with a binding capacity of 280 fmol/mg total cell protein for IIB-MEL-LES cells and of 14 nM with a binding capacity of 206 fmol/mg total cell protein for IIB-MEL-IAN. When specifi­ci­ty was assessed, as seen before, not only androgen and anti­an­dro­gen, but also non-andro­ge­nic com­pounds were able to compete for [3H]-R1881 binding. When immu­nocyto­che­mis­try of IIB-MEL-LES and IIB-MEL-IAN cells was performed for AR, both cell lines were deeply stained in the nu­cleus whe­reas no staining was found for oestrogen and pro­ges­te­rone receptors. Every specimen of mela­no­ma metas­ta­ses tested for the presence of AR was deeply stained, and the intensity of the stai­ning was high in the majority. Several hormones and antihormones were tested for their ability to affect cell proli­fe­ration. On both cell lines, Testosterone, Dihydrotesterone, Oestradiol and Pro­ges­terone significantly stimulated cell proliferation, with reversion by Hydroxy-Flutamide, Casodex or Tamo­xi­fen.

Carboxylate-Bridged Copper(II)-Lanthanide(III) Complexes [{Cu3Ln2(oda)6(H2O)6}.12H2O]n (Ln = Dy, Ho, Er, Y; oda = oxydiacetate Rizzi, Alberto Claudio; Calvo, Rafael; Baggio, Ricardo Fortunato; Garland, María Teresa; Peña, Octavio; Perec, Mireille The hydrothermal reaction of Ln2O3 (Ln = Dy and Ho), Cu(OAc)2·2H2O, and oxydiacetic acid in the approximate mole ratio of 1:3:8 resulted in the formation of two new members of the isostructural series of polymers formulated as [{Cu3Ln2(oda)6(H2O)6}·12H2O]n, crystallizing in the hexagonal crystal system, space group P6/mcc (No. 192). Temperature-dependent magnetic susceptibilities and EPR spectra are reported for the heterometallic compounds Cu−Dy 1, Cu−Ho 2, Cu−Er 3, and Cu−Y 4. The results are discussed in terms of the structure of the compounds, the electronic properties of the lanthanide ions, and the exchange interactions between the magnetic ions.

A nonlinear panel method in the time domain for seakeeping flow problems D'elia, Jorge; Storti, Mario Alberto; Oñate, Eugenio; Idelsohn, Sergio Rodolfo A Lagrangian-type panel method, in the time domain, is  proposed for potential flows with a moving free surface. After a spatial semi-discretization, with a low-order scheme, the instantaneous velocity-potential and normal displacement on the moving free surface, are obtained by means of a time-marching scheme. The kinematic and dynamic boundary conditions, at the free surface, are non-lineal restrictions over the related Ordinary Differential Equation system and, for handle them, an alternative Steklov-Poincare operator  technique is proposed. The method is applied to sloshing like flow problems.

Optimal Design of Cams Cardona, Alberto; Lens, Elisabeth; Nigro, Norberto Marcelo We present a methodology to design cams for motor engine valve trains using a constrained optimization algorithm. The imposed constraints are the maximum valve lift and timings while the objective function is to maximize the time integral of the valve area opened to gas flow. A piecewise analytically defined acceleration is imposed, so that the time instants controlling the profile of accelerations are used as variables for optimization. The strategy takes into account some geometrical constraints, e.g. to avoid interference between intake and exhaust valves, and between valves and piston. Also, minimum and maximum levels of acceleration are limited to avoid excessive forces in the mechanisms chain, and to prevent the possibility of separation between cam and follower. Once an optimal lift profile is determined, the cam shape is computed using an inverse kinematics analysis that takes into account all the geometric nonlinearities introduced by the kinematical chain. Finally, the whole mechanism is verified in a dynamics analysis to check satisfaction of the criteria for design. Comparisons with standard profiles of motion were made. Also, the profile was evaluated in an experimental device, where the actual valve displacement was measured.

All-hexahedral element meshing: Automatic elimination of self-intersecting dual lines Calvo, Nestor Alberto; Idelsohn, Sergio Rodolfo There has been some degree of success in all-hexahedral meshing. Standard methods start with the object geometry defined by means of an all-quadrilateral mesh, followed by the use of the combinatorial dual to the mesh in order to define the internal connectivities among elements. For all of the known methods using the dual concept, it is necessary to first prevent or eliminate self-intersecting (SI) dual lines of the given quadrilateral mesh. The relevant features of SI lines are studied, giving a method to remove them, which avoids deforming the original geometry. Some examples of resulting meshes are shown where the current meshing method has been successfully applied.

Energy of interaction in colloids and its implications in rheological modeling Quemada, Daniel; Berli, Claudio Luis Alberto This work deals with the problem of deriving theoretical connections between rheology and interparticle forces in colloidal suspensions. The nature of interparticle forces determines the colloidal structure (crystalline order due to long range repulsive forces, flocculation due to attractive forces, etc.) and hence, the flow behavior of suspensions. The aim of this article is to discuss how these interactions enter the modeling of rheometric functions, in particular, the shear viscosity. In this sense, the main interactions commonly appearing in colloids are reviewed, as well as the role they play in phase transition behavior. Then, a series of approaches relating the interaction potential to viscosity is examined. The results of applying these models to experimental data are also discussed. Finally, examples of viscosity modeling for different interaction potentials are given, by using the structural model proposed previously by the authors. The possibility of relating the flow behavior of colloidal suspensions to the interaction between particles offers new perspectives for the study and technical applications of these systems.

Lista de los escorpiones bolivianos (Chelicerata: Scorpiones), con notas sobre su distribución; Checklist of the Bolivian scorpions (Chelicerata: Scorpiones), with notes on their distribution Acosta, Luis Eduardo; Ochoa, José A. Se presenta una lista actualizada de los escorpiones de Bolivia. Se mencionan 24 especies (tres de elias con dudas) y una subespecie, pertenecientes a las familias Bothriuridae, Buthidae e luridae. Para cadaespecie se proporciona una referencia bibliografica abreviada, así como la nómina completa de las localidades para las que ha sido citada. Brachistosternus ferrugineus (Thorell) y el genero andino Orobothriurus Maury (Bothriuridae) se citan por prirnera vez para Bolivia. Se discuten los motivos para excluir de la escorpiofauna boliviana a siete especies nominales citadas por autores previos. Se adjunta una lista de las localidades bolivianas, con sus coordenadas, donde se han recolectado escorpiones.; An updated checklist of the scorpions of BoIivia is presented. Twenty four species (three of them, with doubts) and one subspecies, belonging to the families Bothriuridae, Buthidae and luridae are listed. For each species, an abbreviated bibliographic reference and the complete list of known localities are given. Brachistosternus ferrugineus (Thorell) and the Andean genus Orobothriurus Maury (Bothriuridae) are mentioned for the first time from Bolivia. Seven nominal species cited by previous authors are excluded from the Bolivian scorpiofauna, and the reasons for these exclusions are discussed. All Bolivian localities where scorpions have been collected are listed in a gazetteer.

The arginine deiminase pathway in the wine lactic acid bacterium Lactobacillus hilgardii X1B: Structural and functional study of the arcABC genes Arena, Mario Eduardo; Manca, Maria Cristina; Muñoz, Rosario The genes implicated in the catabolism of the amino acid arginine by Lactobacillus hilgardii X1B were investigated to assess the potential for formation of ethyl carbamate precursors in wine. L. hilgardii X1B can use arginine via the arginine deiminase pathway. The complete nucleotide sequence of the arc genes involved in this pathway has been determined. They are clustered in an operon-like structure in the order arcABC. No evidence was found for the presence of a homologue of the arcD gene, coding for the arginine/ornithine antiporter. The arc genes have been expressed in Escherichia coli resulting in arginine deiminase (ArcA), ornithine carbamoyltransfera (ArcB) and carbamate kinase (ArcC) activities. The results indicate the need for caution in the selection of lactic acid bacteria for conducting malolactic fermentation in wine since arginine degradation could result in high amounts of ethyl carbamate.

ACTH regulation of mitochondrial acyl-CoA thioesterase activity in Y1 adrenocortical tumour cells Castilla Lozano, Maria del Rocio; Maloberti, Paula Mariana; Mendez, Carlos Fernando; Paz, Cristina del Valle; Podesta, Ernesto Jorge We have previously purified and cloned a phosphoprotein, Arachidonic acid-Related Thioesterase Involved in Steroidogenesis (ARTISt), involved in steroid synthesis through Arachidonic Acid (AA) release. Arachidonic acid-related thioesterase involved in steroidogenesis resulted to be a member of a new family of acyl-CoA thioesterases. The protein was identified by its biocapacity to increase mitochondrial steroidogenesis in a cell free bioassay. In the present study we measure the activity of ARTISt using arachidonoyl-CoA (AA-CoA) as substrate. We demonstrate that ACTH significantly stimulates endogenous mitochondrial thioesterase activity as early as 5 min after ACTH stimulation of Y1 cells. Nordihydroguaiaretic acid (NDGA), an inhibitor of AA release known to affect steroidogenesis, affects the in vitro activity of recombinant ARTISt and also the endogenous mitochondrial acyl-CoA thioesterases. ACTH activation of the enzyme protected ARTISt to the inhibitory effect of NDGA. These results show that an enzyme that release AA from AA-CoA can be regulated in intact cells by steroidogenic hormones.

Telomerase as a cancer target. Development of new molecules Mengual Gómez, Diego Luis; Armando, Romina Gabriela; Cerrudo, Carolina Susana; Ghiringhelli, Pablo Daniel; Gomez, Daniel Eduardo Telomeres are the terminal part of the chromosome containing a long repetitive and non-codifying sequence that has as function protecting the chromosomes. In normal cells, telomeres lost part of such repetitive sequence in each mitosis, until telomeres reach a critical point, triggering at that time senescence and cell death. However, in most of tumor cells in each cell division a part of the telomere is lost, however the appearance of an enzyme called telomerase synthetize the segment that just has been lost, therefore conferring to tumor cells the immortality hallmark. Telomerase is significantly overexpressed in 80?95% of all malignant tumors, being present at low levels in few normal cells, mostly stem cells. Due to these characteristics, telomerase has become an attractive target for new and more effective anticancer agents. The capability of inhibiting telomerase in tumor cells should lead to telomere shortening, senescence and apoptosis. In this work, we analyze the different strategies for telomerase inhibition, either in development, preclinical or clinical stages taking into account their strong points and their caveats. We covered strategies such as nucleosides analogs, oligonucleotides, small molecule inhibitors, G-quadruplex stabilizers, immunotherapy, gene therapy, molecules that affect the telomere/telomerase associated proteins, agents from microbial sources, among others, providing a balanced evaluation of the status of the inhibitors of this powerful target together with an analysis of the challenges ahead.

Antiphospholipid antibodies impact the protein C (PC) pathway behavior Gennari, Laura C.; Blanco, Alicia N.; Alberto, Maria Fabiana; Grosso, Silvia H.; Peirano, Andrea A.; Lazzari, María Ángela Antiphospholipid antibodies may interfere with the PC pathway, displaying a resistance to the activated PC (resistant phenotype). This effect was evaluated by the APCR and the ProCG systems in 36 lupus anticoagulant samples, yielding abnormal results in 47% of APCRoriginal, 17% of APCRmodified, and 22% of ProCG test. ProCG values correlated with APCRoriginal but not with APCRmodified. Most of lupus anticoagulants affecting the PC pathway showed abnormal APCRoriginal results but not abnormal ProCG values. The different behavior between both systems may be due to the heterogeneity of the antibodies or could be attributed to the fact that, in the ProCG, a PC activator is added, while the APCR employs already activated exogenous PC.

Computer aided model analysis and dynamic simulation of a wastewater treatment plant Mussati, Miguel Ceferino; Gernaey, Krist; Gani, Rafiqul; Jørgensen, Sten A nitrogen removal benchmark was analyzed using the Activated Sludge Models No. 1 (ASM1) and No. 3 (ASM3) in order to establish a basis for designing an experimental comparison of the two model types. Differences in steady state effluent concentrations predicted by both models could to a large extent be explained by different model concepts. The steady state system performance was analyzed by evaluating the Monod factor values, and through a sensitivity analysis of the kinetic model parameters. Both methods complement each other. Analysis of the Monod factor values can lead to determination of parameters to be estimated during model calibration. The steady state system response to manipulation of the potential actuators for control was evaluated via a sensitivity analysis. The concept of relative sensitivity was introduced to compare the relative effect of each actuator in both models. The negative relative sensitivities of X S to four of the five control handles analyzed imply an opposite response of both models, which can be important for control structure design. The analysis of the process behavior to different disturbances showed different dynamics of both models. ASM3 simulation results are easier to interpret because the model structure is more transparent, mainly due to the simpler cell decay model principle considered in ASM3. An inverse response was obtained for the return sludge and nitrate recycle flow rate, indicating that multivariable control design is required.

Brain somatostatin receptors are up-regulated in somatostatin-deficient mice Ramírez, José L.; Mouchantaf, Rania; Kumar, Ujendra; Otero Corchon, Veronica; Rubinstein, Marcelo; Low, Malcolm J.; Patel, Yogesh C. The peptide somatostatin (SST) is widely synthesized in the brain and periphery and acts through a family of five receptors (SSTR1-5) to exert numerous effects. A gene product related to SST, cortistatin (CST), also interacts with SSTR1-5. Here we have investigated the regulation of SSTR1-5 and of CST in SST knockout (SSTKO) mice. The five SSTRs were quantitated individually by subtype-selective binding analysis, by immunocytochemistry, and by mRNA measurement and showed, in the brain of SSTKO mice, up-regulation of subtypes 1, 2, 4, and 5, and down-regulation of SSTR3. Peripheral tissues displayed both subtype- and tissue-specific changes in SSTR1-5 mRNA levels of expression. Lack of SST did not up-regulate normal CST expression in brain nor did it induce its expression in the periphery. SST-like immunoreactivity, however, was induced in the proximal midgut in SSTKO animals, suggesting intestinal expression of a novel SST-like gene.

Nicotinic receptor M3 transmembrane domain: Position 8′ contributes to channel gating de Rosa, Maria Jose; Rayes, Diego Hernán; Spitzmaul, Guillermo Federico; Bouzat, Cecilia Beatriz The nicotinic acetylcholine receptor (nAChR) is a pentamer of homologous subunits with composition α2βεδ in adult muscle. Each subunit contains four transmembrane domains (M1-M4). Position 8′ of the M3 domain is phenylalanine in all heteromeric α subunits, whereas it is a hydrophobic nonaromatic residue in non-α subunits. Given this peculiar conservation pattern, we studied its contribution to muscle nAChR activation by combining mutagenesis with single-channel kinetic analysis. Construction of nAChRs carrying different numbers of phenylalanine residues at 8′ reveals that the mean open time decreases as a function of the number of phenylalanine residues. Thus, all subunits contribute through this position independently and additively to the channel closing rate. The impairment of channel opening increases when the number of phenylalanine residues at 8′ increases from two (wild-type nAChR) to five. The gating equilibrium constant of the latter mutant nAChR is 13-fold lower than that of the wild-type nAChR. The replacement of αF8′, βL8′, δV8′ and εV8′ by a series of hydrophobic amino acids reveals that the structural bases of the observed kinetic effects are nonequivalent among subunits. In the α subunit, hydrophobic amino acids at 8′ lead to prolonged channel lifetimes, whereas they lead either to normal kinetics (δ and ε subunits) or impaired channel gating (β subunit) in the non-α subunits. The overall results indicate that 8′ positions of the M3 domains of all subunits contribute to channel gating.

Detailed structure of configuration space and its importance on ergodic separation of ±J Ising lattices Vogel, Eugenio E.; Ramirez Pastor, Antonio Jose; Nieto Quintas, Felix Daniel A complete and exact characterization of the configuration space of 2-D ±J Ising lattices is performed. A new algorithm is introduced here representing advantages for reaching all states for small samples and doing a non-biased sampling of ground states for larger samples. We report efficient procedures to find all ground states grouped in local ensembles of ground states (LEGs) and also a convenient way of storing and comparing states. Properties of such LEGs differ from some approximate descriptions reported in the literature. The onset of lattice size dependence of properties is discussed. Four different ways of performing ergodic separation are used to calculate order parameters. The most significant way of doing ergodic separation requires previous classification of states in LEGs.

Misiones "ad gentes": Manuales misioneros salesianos para la evangelización de la Patagonia (1910-1924) Nicoletti, Maria Andrea Nos proponemos en este trabajo analizar cómo, a través de un escrito inédito del padre Domenico Milanesio (1843-1922) a modo de reglamento misionero, se desprendieron las directivas y manuales de misión a través de los cuales se llevó a cabo la evangelización “ad gentes” de los Salesianos en la Patagonia. Uno de sus protagonistas volcó a través de sus conocimientos teóricos, pero fundamentalmente por su experiencia de misión, las características que debía tener un misionero que decidiera evangelizar en los territorios del sur. Escrito en medio de un vertiginoso período de misiones y del afianzamiento de la obra de la Congregación salesiana (1880-1934)1, analizaremos cómo se desprendieron de este primer manual, los marcos reglamentarios para la Patagonia que siguieron durante las dos inspectorías sucesivas de los padres Giuseppe Maria Vespignani (1909-1911, Inspectoría San Francisco de Sales) y Luigi Pedemonte (1911-1924, Inspectoría San Francisco Javier) respectivamente, en medio de una crisis ocasionada por la falta de personal y de reorganización de los centros de misión. Los documentos centrales que analizaremos a lo largo de este trabajo son: el reglamento misionero escrito por padre Milanesio en 1810, el Reglamento para las misiones escrito por el padre Vespignani en 1914 y, finalmente, la reunión con los misioneros y el padre Pedemonte en 1914. Complementariamente contamos con la documentación original del Archivo histórico de las Misiones salesianas de la Patagonia Norte, Bahía Blanca, que contiene la mayor parte de los escritos de Domenico Milanesio, complementado con los epistolarios de los padres Vespignani y Pedemonte en los Archivos Centrales salesianos de Buenos Aires y Roma.