Nota preliminar sobre investigaciones arqueológicas en el NE de Entre Ríos y SE de Corrientes: El sitio Rancho Colorado (ENT. FED. 20)

El propósito de esta nota es dar a conocer algunos resultados de las investigaciones antropológicas que se vienen desarrollado en la margen derecha del Río Uruguay Medio; prioritariamente nos ocuparemos aquí del sitio Rancho Colorado, haciendo mención de sus características generales y de las tareas que en él y con los materiales se ejecutaron, definiremos y caracterizaremos las unidades arqueológicas presentes así como lanaturaleza de los materiales de cada una de ellas, presentaremos y evaluaremos nuevasdataciones radiocarbónicas, finalmente relacionaremos estas unidades con otras de laregión y trataremos de proponer algunos planteamientos y conclusiones tentativas. Este sitio catalogado como ENT. FED. 20, fue localizado en el año 1977 en la localidad de Santo Grande (Departamento de Federación, Entre Ríos), zona derápidos en el Río Uruguay que desde 1979 ha sido inundada al formarse el lago de la Represa Hidroeléctrica de Salto Grande, construida pocos kilómetros al sur

In vitro dynamics of HIV-1 BF intersubtype recombinants genomic regions involved in the regulation of gene expression

HIV-1 intersubtype recombination is a very common phenomenon that has been shown to frequently affect different viral genomic regions. Vpr and Tat are viral proteins known to interact with viral promoter (LTR) during the replication cycle. This interaction is mainly involved in the regulation of viral gene expression, so, any structural changes in the LTR and/or these regulatory proteins may have an important impact on viral replication and spread. It has been reported that these genetic structures underwent recombination in BF variants widely spread in South America. To gain more insight of the consequences of the BF intersubtype recombination phenomenon on these different but functionally related genomic regions we designed and performed and in vitro study that allowed the detection and recovery of intersubtype recombinants sequences and its subsequent analysis. Our results indicate that recombination affects differentially these regions, showing evidence of a time-space relationship between the changes observed in the viral promoter and the ones observed in the Vpr/Tat coding region. This supports the idea of intersubtype recombination as a mechanism that promotes biological adaptation and compensates fitness variations

A blind hierarchical coherent search for gravitational-wave signals from coalescing compact binaries in a network of interferometric detectors

We describe a hierarchical data analysis pipeline for coherently searching for gravitational wave (GW) signals from non-spinning compact binary coalescences (CBCs) in the data of multiple earth-based detectors. It assumes no prior information on the sky position of the source or the time of occurrence of its transient signals and, hence, is termed "blind". The pipeline computes the coherent network search statistic that is optimal in stationary, Gaussian noise, and allows for the computation of a suite of alternative statistics and signal-based discriminators that can improve its performance in real data. Unlike the coincident multi-detector search statistics employed so far, the coherent statistics are different in the sense that they check for the consistency of the signal amplitudes and phases in the different detectors with their different orientations and with the signal arrival times in them. The first stage of the hierarchical pipeline constructs coincidences of triggers from the multiple interferometers, by requiring their proximity in time and component masses. The second stage follows up on these coincident triggers by computing the coherent statistics. The performance of the hierarchical coherent pipeline on Gaussian data is shown to be better than the pipeline with just the first (coincidence) stage.Comment: 12 pages, 3 figures, accepted for publication in Classical and Quantum Gravit

The configuration of the seismic zone and the downgoing slab in southern Peru

Using data from temporary networks of portable seismographs in southern Peru, we located 888 shallow and intermediate depth events near a proposed discontinuity in the seismic zone there. These events reveal a prominent contortion, instead of a discontinuity, that trends approximately N80°E, parallel to the direction of relative plate motion. North of about 15°S, the seismic zone beneath Peru is nearly horizontal, but south of about 15.5°S, it dips at about 25°. Volcanoes lie above the more steeply dipping zone where earthquakes occur between 120 and 140 km, and the volcanic line in southern Peru stops abruptly at the contortion

Muon-spin rotation and magnetization studies of chemical and hydrostatic pressure effects in EuFe_{2}(As_{1-x}P_{x})_{2}

The magnetic phase diagram of EuFe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ was investigated by means of magnetization and muon-spin rotation studies as a function of chemical (isovalent substitution of As by P) and hydrostatic pressure. The magnetic phase diagrams of the magnetic ordering of the Eu and Fe spins with respect to P content and hydrostatic pressure are determined and discussed. The present investigations reveal that the magnetic coupling between the Eu and the Fe sublattices strongly depends on chemical and hydrostatic pressure. It is found that chemical and hydrostatic pressure have a similar effect on the Eu and Fe magnetic order.Comment: 11 pages, 10 figure

Sílice de las Algas Diatomeas (Clase Bacillariophyceae) como material complejo y su importancia nanotecnológica

The presence of mineral deposition is very common in microorganisms, plants, mushrooms and mammals. This organisms are an excellent natural model to study the relation between the principal parts involved in the process, the biopolymeric and mineral phases. The importance of this kind of studies is the relation with nanotechnology. Being a relatively new science, nanotechnology studies the chemical and physical phenomena is a scale under the 500 nanometers. When the system under study has a biological significance, with active biologic structures, the term bionanotechnology is used. This is the case of the study of the biomineralization in diatomeas seaweed. Due to the difficulty in the production of controlled micro and nanostructures containing silica (SiO2), this study is relevant. The possible technological applications of this kind of crystals are drug liberation structures, photovoltaic cells and high performance ceramic materials. Factors that affect the geometry, mechanical and physicochemical properties are poorly understood, whereby this kind of studies are important. Understanding the interactions and processes involved in the production of biological crystals could yield to a rational production of new and sophisticated nanostructured material with a broad application in nanotechnology (hybrid semiconductors), biology and biomedicime (biomaterials, drug liberation structures). In the work we establish a “bottom up” draft of the synthesis of “biosilica” by diatomeas emphasizing the impact in nanotechnology.La presencia de depósitos minerales es muy común en microorganismos, plantas, hongos y mamíferos. Estos organismos son, por lo tanto, un modelo natural excelente para estudiar la relación entre las principales partes que los componen, es decir la fase biopolímérica y la mineral. La importancia de este tipo de estudios se relaciona directamente con la nanotecnología, una rama científica relativamente reciente, encargada de estudiar los fenómenos químicos y físicos a escalas menores a los 500 nm. Cuando el sistema de estudio tiene importancia biológica, posee estructuras biológicamente activas o procede de un sistema biológico, se llama entonces bionanotecnología. Este es el caso del estudio de la biomineralización en las algas diatomeas. Esta línea de investigación tiene alta relevancia por la dificultad de producir micro y nanoestructuras altamente controladas de dióxido de silicio o sílice (SiO2), un tipo de vidrio que tiene potencialmente aplicaciones tecnológicas en liberación de drogas, celdas solares y materiales cerámicos de alto rendimiento. Los factores que afectan la geometría, las propiedades mecánicas y fisicoquímicas en estas estructuras son pobremente comprendidos, por lo que este tipo de estudios es de suma importancia. Si se logra entender las interacciones y los procesos de formación en estos sistemas que producen vidrio en entes biológicos, podremos acercarnos racionalmente a la síntesis de nuevos y sofisticados materiales nanoestructurados, con aplicaciones en una gran gama de áreas que van desde la nanotecnología (semiconductores híbridos) hasta la biología y biomedicina (biomateriales y estructuras liberadoras de drogas). En el presente trabajo se hace un esbozo “ascendente” (bottomup) de la síntesis de “biosilice” en diatomeas donde se enfatiza la importancia de este fenómeno en la nanotecnología

Inventory and review of the Mio–Pleistocene São Jorge flora (Madeira Island, Portugal): palaeoecological and biogeographical implications

The occurrence of plant fossils on Madeira Island has been known since the mid-nineteenth century. Charles Lyell and George Hartung discovered a leaf bed rich in Lauraceae and fern fossils at S~ao Jorge in 1854. The determinations were controversial but a full review was never performed. Here we propose possible geological settings for the fossiliferous outcrop, and present an inventory and a systematic review of the surviving specimens of the S~ao Jorge macroflora. The S~ao Jorge leaf bed no longer outcrops due to a landslide in 1865. It was possible to establish the two alternative volcano stratigraphical settings in the sedimentary intercalations from the Middle Volcanic Complex, ranging in age from 7 to 1.8 Ma. The descriptions of Heer (1857), Bunbury (1859) and Hartung & Mayer (1864) are reviewed based on 82 surviving specimens. From the initial 37 taxa, we recognize only 20: Osmunda sp., Pteridium aquilinum, Asplenium cf. onopteris, aff. Asplenium, cf. Polystichum, cf. Davallia, Woodwardia radicans, Filicopsida gen. et sp. indet. 1 and 2, Ocotea foetens, Salix sp., Erica arborea, cf. Vaccinium, Rubus sp, cf. Myrtus, Magnoliopsida gen. et sp. indet. 1 to 3, Liliopsida gen. et sp. indet. 1. Magnoliopsida gen. et sp. indet. 4 is based on one previously undescribed flower or fruit. The floristic composition of the S~ao Jorge fossils resembles the current floristic association of temperate stink laurel (Ocotea foetens) forest, suggesting a warm and humid palaeoclimate and indicating that laurel forests were present in Macaronesia at least since the Gelasian, a time when the palaeotropical geofloral elements were almost extinct in Europe.info:eu-repo/semantics/publishedVersio

Chronology of the sedimentary processes during the postglacial sea level rise in two estuaries of the Algarve coast, Southern Portugal

Four profiles of estuarine sediments obtained from boreholes drilled in the Algarve, Southern Portugal were studied in order to reconstruct the process of sediment accumulation driven by the postglacial sea level rise. In addition to the sedimentological analysis, the Foraminifera Index of Marine Influence (FIMI) permitted assessment of the nature and organization of sedimentary facies in the BelicheeGuadiana and Gilão-Almargem estuaries. The Beliche- Guadiana CM5 and Almargem G2 profiles accumulated in a sheltered environment, with the former presenting an almost continuous record of the sea level rise since ca 13 000 cal yr BP. The G1 and G3 profiles from the Gilão-Almargem area represent a more discontinuous record of the last 8000 years, which accumulated in the more dynamic environment of an outer estuary. The integration of all radiocarbon ages of dated levels, led to an estimate of sediment accumulation rates. Assuming a constant position of the sediment surface with respect to the tidal range and a negligible compaction of sediment, the sea level rose at the rate of 7 mm yr ^-1 in the period from 13 000 to 7500 cal yr BP. This process slowed down to ca 0.9 mm yr 1 from 7500 cal yr BP until the present. The marked historical change in the rate of sediment accumulation in these estuaries also occurred with the accumulation of organic matter and is, therefore, important data for global biogeochemical models of carbon. The main obstacle to obtain higher temporal resolution of the sedimentary processes was the intense anaerobic respiration of organic matter via sulphate reduction, which did not allow any accumulation of peat and, furthermore, led to erasure of the palaeontological record by acid formed from the subsequent oxidation of sulphides.FORMOSE- Sources and Retention of Organic Matter in the Estuarine Zones, PRAXIS XXI program of Portuguese Science and Technology Foundation and project MEGASIG, INTERREG IIIa program of the European Union