Quantitative characterisation of contourite deposits using medical CT

Five sediment cores, retrieved from four different depositional contouritic morphological settings (a sheeted drift, a confined mounded drift, a mounded elongated drift and a plastered drift) from the Northern Gulf of Cadiz and the Alboran Sea have been analysed using medical X-ray computed tomography (medical CT). A quantitative approach has been used, resulting in a workflow that delineates several radio-density ranges based on the Hounsfield Unit (HU) histogram of each core and tracks these ranges throughout the cores. In order to derive the geological significance, the radio-density ranges of all cores have been compared to non-destructive, continuous chemical and physical proxies as well as grain size measurements. The highest correlations occurred between high HU and proxies indicating elevated bottom currents, such as Zr/Al and sortable silt. Additionally, a continuous increase in average HU and inferred bottom current velocities, needed for the creation of the specific contourite setting, could be observed throughout the five cores. Despite imperfections and the requirement of additional research, promising results have been obtained which could improve the detection of diagnostic criteria for contourites. Moreover, the CT data can give more conclusive evidence on the nature of the (contourite) sedimentary sequence boundaries

The role of late Quaternary tectonic activity and sea-level changes on sedimentary processes interaction in the Gulf of Cadiz upper and middle continental slope (SW Iberia)

A morphological and seismic-stratigraphic analysis of the Gulf of Cadiz area near the Strait of Gibraltar is presented in this work, focused on the sedimentary evolution of the upper and proximal middle-continental slope since the Mid-Pleistocene. Based on the analysis of seismic reflection profiles and swath bathymetry data, this work analyses the close influence of the activity of buried and outcropping diapiric ridges and late Quaternary sea-level changes on the evolution of contouritic features related to the Mediterranean Outflow Water (MOW) and Eastern North Atlantic Central Water (ENACW), gravitational features and fluid-escape structures. The stratigraphic architecture reveals that, under active diapiric deformation, the upper slope plastered drift grew during low sea-level stages, when sediment supply was high and the ENACW swept the upper slope, contrasting with the present-day highstand situation dominated by northwest-trending MOW flow. The south-estward ENACW flow forced asymmetry and lateral migration of gullies incised in the plastered drift. Two evolutionary stages have been established: 1) After the Mid Pleistocene, activity of diapirs with a NE trend determined the location of the deepest depressions which were infilled by plastered contouritic drifts; 2) Between Late Quaternary and present, a drastic change of buried diapirs growth pattern and orientation to a NW trend enhanced slope-derived gravitational processes affecting the bottom current dynamics. Adjustments to tectonic changes led to a phase of plastered drift growth on the upper slope during which depocenters varied their distribution and orientation. In a long-term the structural control on sedimentation shows a northwestward displacement of deformation, resulting in an overall extension of the contourite depositional system to the NW. In a short-term, sea-level changes favored drift deposition, gullies incision and the strengthening of water masses. This work evidences the importance of tectonic deformation in sedimentation at recent time scales, and the twodirectional interplay between recent tectonic activity and bottom current dynamics.Versión del edito

In silico and In vitro analysis of MAP3773c protein from Mycobacterium avium subsp. Paratuberculosis

Paratuberculosis is a disease caused by Mycobacterium avium subsp. paratuberculosis (MAP). It is of great interest to better understand the proteins involved in the pathogenicity of this organism in order to be able to identify potential therapeutic targets and design new vaccines. The protein of interest–MAP3773c–was investigated, and molecular modeling in silico, docking, cloning, expression, purification, and partial characterization of the recombinant protein were achieved. In the in silico study, it was shown that MAP3773c of MAP has 34% sequence similarity with Mycobacterium tuberculosis (MTB) FurB, which is a zinc uptake regulator (Zur) protein. The docking data showed that MAP3773c exhibits two metal-binding sites. The presence of structural Zn2+ in the purified protein was confirmed by SDS-PAGE PAR staining. The purification showed one band that corresponded to a monomer, which was confirmed by liquid chromatography–mass spectrometry (LC-MS). The presence of a monomer was verified by analyzing the native protein structure through BN-SDS-PAGE (Native Blue (BN) Two-Dimensional Electrophoresis) and BN–Western blotting. The MAP3773c protein contains structural zinc. In conclusion, our results show that MAP3773c displays the features of a Fur-type protein with two metal-binding sites, one of them coordinating structural Zn2+

Resultados preliminares de las emisiones COVs generada por el tráfico de vehículos por carretera en Santa Cruz de Tenerife

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)Los hidrocarburos emitidos directamente por los vehículos influyen en la salud humana como consecuencia de su toxicidad (e.g. benceno), pero además estos compuestos son precursores de contaminantes atmosféricos secundarios formados por procesos fotoquímicos tales como el ozono. Investigaciones sobre las variaciones espaciales y temporales de compuestos orgánicos volátiles COVs en el interior del túnel de la Avda. Tres de Mayo, SIC de Tenerife, permiten estimar la emisión de COVs generada por el tráfico de vehículos por carretera en SIC de Tenerife. Los resultados preliminares reflejan que las emisiones de específicos COVs tales como el benceno, tolueno, etilbenceno y xilenos (BTEX) generadas por el trafico que entra y sale diariamente de SIC de Tenerife es del orden de decenas de kilogramos por kilómetro recorrido

Emisiones no-controladas a la atmósfera de gases inorgánicos tóxicos (CO, H2S, HG0 Y NH3) por vertederos en la Isla de Tenerife

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna

Emisiones no controladas a la atmósfera de COVs por el vertedero de Arico, Tenerife, Islas Canarias

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)Un gran número de compuestos orgánicos volátiles (COVs) están presentes en el biogas de los vertederos en cantidades trazas. A pesar de la existencia de sistemas de extracción de biogas en los vertederos para reducir el impacto medio ambiental de estas emisiones, una fracción de las mismas puede escapar a la atmósfera a través de la superficie del vertedero de forma no controlada. En el año 2002 se materializó un estudio con la finalidad de estimar la emisión no controlada de COVs por el vertedero de Arico. La emisión no-controlada de COVs a la atmósfera por el vertedero de Arico se estimó en 2.108 kg·cf 1, de los cuales 1.638 kg·cf1 son componentes BTEX

Diversidad fúngica de las reservas de la biosfera de Cuba / Fungus diversity of the reserves of biosphere in Cuba

Se relacionan los hongos que han sido recolectados en las seis reservas de la biosfera, declaradas por la UNESCO, que forman parte del Sistema Nacional de Áreas Protegidas de Cuba. Se presentan de manera comparativa el número de especies, familias y órdenes que se encuentran en cada una de ellas y las especies que son comunes a todas las reservas.The fungus that have been collected in the six reserves of biosphere, declared by UNESCO, that are included in the National System of Protected Areas in Cuba are offered. There is a presentation by comparison of the number of species, families and orders that are found in each of them and the species that are common in all reserves.

The porin and the permeating antibiotic: A selective diffusion barrier in gram-negative bacteria

Gram-negative bacteria are responsible for a large proportion of antibiotic resistant bacterial diseases. These bacteria have a complex cell envelope that comprises an outer membrane and an inner membrane that delimit the periplasm. The outer membrane contains various protein channels, called porins, which are involved in the influx of various compounds, including several classes of antibiotics. Bacterial adaptation to reduce influx through porins is an increasing problem worldwide that contributes, together with efflux systems, to the emergence and dissemination of antibiotic resistance. An exciting challenge is to decipher the genetic and molecular basis of membrane impermeability as a bacterial resistance mechanism. This Review outlines the bacterial response towards antibiotic stress on altered membrane permeability and discusses recent advances in molecular approaches that are improving our knowledge of the physico-chemical parameters that govern the translocation of antibiotics through porin channel

Dark coupling

The two dark sectors of the universe - dark matter and dark energy - may interact with each other. Background and linear density perturbation evolution equations are developed for a generic coupling. We then establish the general conditions necessary to obtain models free from early time non-adiabatic instabilities. As an application, we consider a viable universe in which the interaction strength is proportional to the dark energy density. The scenario does not exhibit "phantom crossing" and is free from instabilities, including early ones. A sizeable interaction strength is compatible with combined WMAP, HST, SN, LSS and H(z) data. Neutrino mass and/or cosmic curvature are allowed to be larger than in non-interacting models. Our analysis sheds light as well on unstable scenarios previously proposed.Comment: 30 pages, 10 figure

Aplicación y uso de la espectrometría de infrarrojo de campo abierto (OP-FTIR) para la monitorización de contaminantes atmosféricos

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)La espectroscopia de absorción infrarroja de campo abierto (OP-FTIR) se ha aplicado en los últimos años en la medida de componentes traza y contaminantes en la atmósfera procedentes tanto de fuentes naturales como antropogénicas. Con la finalidad de evaluar la emisión de gases contaminantes asociada tanto a la producción de biogas por vertederos como al tráfico rodado, en Julio de 2003 se realizó un estudio preliminar consistente en la medida tanto espectral como radiométrica de gases en el ambiente atmosférico del vertedero de Arico y de la autopista Norte Santa Cruz-La Laguna, en Tenerife. Los resultados reflejaron valores medios de metano (CH4), monóxido de carbono (CO) y acetileno (C2H2) superiores a los estimados para la troposfera, indicando que tanto los vertederos como el tráfico rodado son importantes fuentes de contaminación atmosférica en la isla de Tenerife