El problema de diagenesis y metamorfismo en el grupo de Bokkeveld de Sud África y las Sierras Australes de la provincia de Buenos Aires

En base a la estratigrafía y tectónica del Grupo de Bokkeveld, suministrado por S0EK0R de Sud Africa, se han ubicado las muestras utilizadas en el presente trabajo. Las muestras de las Sierras Australes, fueron tomadas de los Grupos de Ventana y Pillahuincó, de uno de los perfiles realizados por T. Suero (1967). El estudio Petrográfico de las Rocas de Bokkeveld y S. de la Ventana, muestran una gran similitud y homogeneidad entre ellas. Deben considerarse como rocas Sedimentarias, por la presencia de montmorillonita y de minerales interestratificados de arcillas. Las plagioclasas presentan una composición demasiado básica para incluir las rocas dentro del metamorfismo de bajo rango. Lá presencia de epidoto en las formaciones Bonete y Tunas se considera de origen hidrotermal.The samples used in this study have been selected taking into account the stratigraphy and tectonic of the Bokkeveld Group, submitted by SOEKOR Co. The rocks from the Southern Hills, Buenos Aires, were obtained from Ventana and Pilla- huincd Groups, on the basis of the profile from T. Suero. The petrographic studies of the rocks of Bokkeveld and Ventana Hills, show that there is homogenity and similitude in them. They should be considered as sedimentary rocks, sincje there is montmorillonite and interstratified clay minerals in them. The plagioclases are too basic to include this rocks in the very low range of metamorphism. Epidote, in Bonete and Tunas Formations, should be considered of hydrothermal and not of metamorphic origin

Estudio mineralógico de algunas calcedonias argentinas

El trabajo se realizó teniendo en cuenta la reacción de este mineral con el cemento portland, la cuál produce efectos perjudiciales en los hormigones. Se comprobó que en ciertos casos la reacción no se produce. Se investigan las causas de tal comportamiento. El material utilizado para el estudio proviene de los ríos Uruguay y Paraná, ya que son las principales fuentes de abastecimiento de agregados del Gran Buenos Aires. Las "calcedonias" estudiadas están compuestas por un agregado fino de cuarzo, calcedonia y ópalo. La proporción relativa de dichos minerales condiciona la reactividad de los mismos.This paper deals with the reaction between chalcedony and Portland cement. This reaction damages the structure of the reinforced concrete, when aggregates of this kind are used for that purpose. In certain cases the concerned reaction do not take place. For that reason a detailed study was carried out to determine the behavior of the materials. The aggregates used for this, study come from Paraná and Uruguay rivers; the sediments of this area supply enough material from the Gran Buenos Aires market. The so call "chalcedony" studies are mainly composed of fine quartz, chalcedony and opal. The relative amounts of these minerals are thought to affect the behavior of the aggregates when they are mixed with portland cement

Lazy states: sufficient and necessary condition for zero quantum entropy rates under any coupling to the environment

We find the necessary and sufficient conditions for the entropy rate of the system to be zero under any system-environment Hamiltonian interaction. We call the class of system-environment states that satisfy this condition lazy states. They are a generalization of classically correlated states defined by quantum discord, but based on projective measurements of any rank. The concept of lazy states permits the construction of a protocol for detecting global quantum correlations using only local dynamical information. We show how quantum correlations to the environment provide bounds to the entropy rate, and how to estimate dissipation rates for general non-Markovian open quantum systems.Comment: 4 page

La promoción del desarrollo de habilidades metacognoscitivas en los alumnos del nivel medio superior: una propuesta de abordaje para el Taller de Programación y Cómputo

Esta investigación se realizó con el objetivo de construir un modelo de intervención para promover el desarrollo del pensamiento metacognoscitivo en alumnos de bachillerato en la asignatura de Taller de Programación y Cómputo. El trabajo estuvo enfocado en saber cómo se promueve el desarrollo de la metacognición, para lo que se diseñaron distintas estrategias. La investigación se desarrolló a través de una metodología cualitativa; se emplearon diversos instrumentos para recopilar información que permitiera recolectar evidencias de las estrategias empleadas por el profesor para promover este tipo de pensamiento y de los productos resultantes de la reflexión metacognitiva. En el análisis de los datos se encontraron seis categorías que permiten ver los modos como las estrategias metacognoscitivas fueron puestas en práctica y cómo los alumnos ejercieron su pensamiento de modo metacognoscitivo

How state preparation can affect a quantum experiment: Quantum process tomography for open systems

We study the effects of preparation of input states in a quantum tomography experiment. We show that maps arising from a quantum process tomography experiment (called process maps) differ from the well know dynamical maps. The difference between the two is due to the preparation procedure that is necessary for any quantum experiment. We study two preparation procedures, stochastic preparation and preparation by measurements. The stochastic preparation procedure yields process maps that are linear, while the preparations using von Neumann measurements lead to non-linear processes, and can only be consistently described by a bi-linear process map. A new process tomography recipe is derived for preparation by measurement for qubits. The difference between the two methods is analyzed in terms of a quantum process tomography experiment. A verification protocol is proposed to differentiate between linear processes and bi-linear processes. We also emphasize the preparation procedure will have a non-trivial effect for any quantum experiment in which the system of interest interacts with its environment.Comment: 13 pages, no figures, submitted to Phys. Rev.

Positivity in the presence of initial system-environment correlation

The constraints imposed by the initial system-environment correlation can lead to nonpositive Dynamical maps. We find the conditions for positivity and complete positivity of such dynamical maps by using the concept of an assignment map. Any initial system-environment correlations make the assignment map nonpositive, while the positivity of the dynamical map depends on the interplay between the assignment map and the system-environment coupling. We show how this interplay can reveal or hide the nonpositivity of the assignment map. We discuss the role of this interplay in Markovian models.Comment: close to the published version. 5 pages, 1 figur

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

We analysed collisionless N-body simulations of intermediate and minor dry mergers onto S0s to test whether these mergers can generate S0 galaxies with kinematics intermediate between fast and slow rotators. We find that minor mergers induce a lower decrease of the global rotational support than encounters of lower mass ratios, which results in S0s with properties intermediate between fast and slow rotators. The resulting remnants are intrinsically more triaxial, less flattened, and span the whole range of apparent ellipticities up to $\epsilon_\mathrm{e} \sim 0.8$. They do not show lower apparent ellipticities in random projections than initially; on the contrary, the formation of oval distortions and the disc thickening increase the percentage of projections at $0.4 < \epsilon_\mathrm{e} < 0.7$. In the experiments with S0b progenitor galaxies, minor mergers tend to spin up the bulge and to decrease slightly its intrinsic ellipticity, whereas in the cases of primary S0c galaxies they keep the rotational support of the bulge nearly constant and decrease significantly its intrinsic ellipticity. The remnant bulges remain nearly spherical ($B/A \sim C/A > 0.9$), but exhibit a wide range of triaxialities ($0.20 < T < 1.00$). In the plane of global anisotropy of velocities ($\delta$) vs. intrinsic ellipticity ($\epsilon_\mathrm{e,intr}$), some of our models extend the linear trend found in previous major merger simulations towards higher $\epsilon_\mathrm{e,intr}$ values, while others depart from it. This is consistent with the wide dispersion exhibited by real S0s in this diagram compared with ellipticals, which follow the linear trend drawn by major merger simulations. The different trends exhibited by ellipticals and S0 galaxies in the $\delta$ - $\epsilon_\mathrm{e}$ diagram may be pointing to the different role played by major mergers in the build-up of each morphological type.Comment: Corrected typos. 20 pages, 14 figures. Accepted for publishing in A&

Haemophilus parasuis Subunit Vaccines Based on Native Proteins with Affinity to Porcine Transferrin Prevent the Expression of Proinflammatory Chemokines and Cytokines in Pigs

8 p.The expression of chemokines (CCL-2 and CXCL-8) and cytokines (IL-1, IL-1, IL-6, TNF-, and IL-10) was evaluated by RTqPCR in colostrum-deprived pigs vaccinated and challenged with Haemophilus parasuis serovar 5. Two vaccines containing native proteins with affinity to porcine transferrin (NPAPTim and NPAPTit) were tested, along with two control groups: one inoculated with PBS instead of antigen (challenge group (CHG)), and another one nonimmunized and noninfected (blank group). The use of NPAPTim and NPAPTit resulted in complete protection against H. parasuis (no clinical signs and/or lesions), and both vaccines were capable of avoiding the expression of the proinflammatory molecules to levels similar to physiological values in blank group. However, overexpression of all proinflammatory molecules was observed in CHG group, mainly in the target infection tissues (brain, lungs, and spleen). High expression of CCL-2, CXCL-8, IL-1, IL-1, and IL-6 can be considered one of the characteristics of H. parasuis infection by serovar 5S

Neutral molecular markers support common origin of aluminium tolerance in three congeneric grass species growing in acidic soils

Aluminium (Al) toxicity is the main abiotic stress limiting plant productivity in acidic soils that are widely distributed among arable lands. Plant species differ in the level of Al resistance showing intraspecific and interspecific variation in many crop species. However, the origin of Al-tolerance is not well known. Three annual species, difficult to distinguish phenotypically and that were until recently misinterpreted as a single complex species under Brachypodium distachyon, have been recently separated into three distinct species: the diploids B. distachyon (2n = 10) and B. stacei (2n = 20), and B. hybridum (2n = 30), the allotetraploid derived from the two diploid species. The aims of this work were to know the origin of Al-tolerance in acidic soil conditions within these three Brachypodium species and to develop new DNA markers for species discrimination. Two multiplex SSR-PCRs allowed to genotype a group of 94 accessions for 17 pentanucleotide microsatellite (SSRs) loci. The variability for 139 inter-microsatellite (ISSRs) markers was also examined. The genetic relationships obtained using those neutral molecular markers (SSRs and ISSRs) support that all Al-tolerant allotetraploid accessions of B. hybridum have a common origin that is related with both geographic location and acidic soils. The possibility that the adaptation to acidic soils caused the isolation of the tolerant B. hybridum populations from the others is discussed. We finally describe a new, easy, DNA barcoding method based in the upstream-intron 1 region of the ALMT1 gene, a tool that is 100 % effective to distinguish among these three Brachypodium species