158 research outputs found

    Combined use of the GGSFT data base and on Board Marine Collected Data to Model the Moho Beneath the Powell Basin, Antarctica

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    The Powell Basin is a small oceanic basin located at the NE end of the Antarctic Peninsula developed during the Early Miocene and mostly surrounded by the continental crusts of the South Orkney Microcontinent, South Scotia Ridge and Antarctic Peninsula margins. Gravity data from the SCAN 97 cruise obtained with the R/V Hespérides and data from the Global Gravity Grid and Sea Floor Topography (GGSFT) database (Sandwell and Smith, 1997) are used to determine the 3D geometry of the crustal-mantle interface (CMI) by numerical inversion methods. Water layer contribution and sedimentary effects were eliminated from the Free Air anomaly to obtain the total anomaly. Sedimentary effects were obtained from the analysis of existing and new SCAN 97 multichannel seismic profiles (MCS). The regional anomaly was obtained after spectral and filtering processes. The smooth 3D geometry of the crustal mantle interface obtained after inversion of the regional anomaly shows an increase in the thickness of the crust towards the continental margins and a NW-SE oriented axis of symmetry coinciding with the position of an older oceanic spreading axis. This interface shows a moderate uplift towards the western part and depicts two main uplifts to the northern and eastern sectors

    QSAR and molecular docking modelling of anti-leishmanial activities of organic selenium and tellurium compounds

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    Leishmaniasis affects mainly rural areas and the poorest people in the world. A computational study of the antileishmanial activity of organic selenium and tellurium compounds was performed. The 3D structures of the compounds were optimized at the wb97xd/lanl2dz level and used in the quantitative structure-activity relationship (QSAR) analysis. The antileishmanial activity was measured by L. donovani β carbonic anhydrase inhibition (Ki) and the half-maximal inhibitory concentration (IC50) against L. infantum amastigotes. The dataset was divided into training (75%) and test sets (25%) by using a k-means clustering algorithm. For pKi prediction, model M3 with seven 3D topographic descriptors was characterized by the following statistical parameters: r 2 = 0.879, Q 2 LOO = 0.822, and Q 2 ext = 0.840. For pIC50 prediction, model M12 with six attributes was characterized by the following statistical parameters: r 2 = 0.907, Q 2 LOO = 0.824, and Q 2 ext = 0.795. Both models met all the requirements of Tropsha´s test, which implies predictions of pIC50 and pKi activities with high accuracy. Concomitantly, favourable interactions of the sulphonamide group with the Zn atom in the protein were revealed by the docking analysis

    Inversión numérica 3D de datos gravimétricos procedentes de campañas marinas y de satélite. Aplicación a un área antártica

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    Se presenta la modelización gravimétrica de la corteza oceánica en la zona de central del Pasaje del Drake, en la Fractura Shackleton (Antártida) a modo de ejemplo de aplicación de inversión numérica en 3D de datos de gravedad discutiendo los métodos utilizados. Los datos tratados corresponden a una campaña realizada por el barco oceanográfico español Hespérides y a la base «Global Gravity Grid and Global Sea Floor Topography» (GGSFT) (Sandwell y Smith, 1997). Se comentan y analizan las limitaciones de aplicación del Método de Factorización Espectral (Spector y Grant, 1970) que permite separar la contribución de las distintas fuentes de la anomalía de gravedad. En particular, en el caso de datos marinos y satelitales que hemos utilizado se considera el efecto negativo en el espectro radial de la mezcla indiscriminada de datos de diverso origen. Se comenta, también, el método de inversión utilizado basado en Parker (1973) y la utilización de la corrección de placa de agua (WPC) aplicada a la anomalía de Aire libre para la obtención de la anomalía Total, punto de partida del proceso de inversión

    Estudi computacional de les interaccions moleculars entre l'àcid itacònic i compostos antimalàrics: un pas important per al disseny racional de sistemes d'alliberament controlat de fàrmacs

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    Las interacciones moleculares entre cuatro antimaláricos: cloroquina, primaquina, quinina y amodiaquina, con un dímero del ácido itacónico, fueron estudiadas a través de la teoría del funcional de la densidad usando B3LYP/++6-31G(d,p) y el modelo CPCM para el solvente. Cloroquina, primaquina y quinina presentan interacción apreciable con el dímero del ácido itacónico, con energías de interacción en el rango de -17 hasta -6,7 kcal/mol, de naturaleza exotérmica, a través de un proceso de fisisorción. El valor positivo de la energía de interacción para la amodiaquina sugiere una menor probabilidad de que este sea adsorbido por un dímero de ácido itacónico. Los cálculos NBO y la aplicación de la teoría de perturbación de segundo orden indican transferencia de carga desde los compuestos cloroquina y primaquina. Adicionalmente, los resultados sugieren que las interacciones principales son de naturaleza polar, donde los enlaces de hidrógenos juegan un rol principal. Los resultados encontrados a través del método CPCM indican que los complejos entre el dímero de ácido itacónico con cloroquina y primaquina son bastante estables en disolución acuosa; además presentan valores adecuados de LogP y momento dipolar, indicando alta la interacción con el solvente que permitiría el hinchamiento y la liberación controlada de estos fármacos.The molecular interactions between four widely used antimalaric i.e, chloroquine, primaquine, quinine and amodiaquine, with an itaconic acid dimer as a hydrogel model, have been studied by the mean of the Density Functional Theory calculation in both, vacuum and water environment, using B3LYP/++6-31G(d,p) basis set and PCM model of solvent. Chloroquine, primaquine, and quinine show a suitable interaction with the itaconic acid dimer, with binding energy into the range of -17 to -6.7 kcal/ mol. These values of binding energies suggest the formation of stable and exothermic complexes in the range of physisorption energy. By contrast, the positive value of binding energy for amodiaquine indicates a little chance to be absorbed into the hydrogel polymer. The NBO calculation and the second order perturbation theory indicate a strong charge-transference from chloroquine and primaquine to itaconic acid dimer. In addition, these results suppose the interactions are mainly polar in nature where the hydrogen bond plays a pivotal role in complex stabilization. On the other hand, the CPCM calculations suggest the chloroquine and primaquine complex are stables, with suitable values of both, LogP and dipole momentum implying the swelling of these complex in water and the eventual drugs controlled-delivery from the polymeric matrix

    Grosor de la corteza oceánica en dorsales de expansión y alrededores en el Paso del Drake (Antártida) a partir de inversión numérica de datos gravimétricos

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    The high density of geophysical data (gravity, bathymetry...) collected in the ANTPAC 97/98 cruise by the Spanish BIO Hespérides allows us to obtain the crustal thickness of the areas near the intersection of the Shackleton Fracture Zone and the West Scotia Ridge (Z1), and the P2 segment of the Phoenix-Antarctic Ridge (Z2) by means of inversion methods. Data were merged with that of the Global Gravity Grid and the Global Sea Floor Topography (Sandwell and Smith, 1997). The effect of the bathymetry on the Free Air anomaly was eliminated previously. Differences in the crustal thickness in both areas are presented

    Statistical features of seismoelectric signals prior to M7.4 Guerrero-Oaxaca earthquake (México)

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    In this paper a statistical analysis of seismoelectric ULF signals prior to the M7.4 Guerrero-Oaxaca earthquake (EQ) occurred at the Mexican Pacific coast on 14 September 1995, has been performed. The signals were simultaneously recorded at three monitoring stations from the last months of 1994 until July of 1996. The nonlinear time series methods of Higuchi fractal dimension (HFD) and detrended fluctuation analysis (DFA) have been used. In the three data sets we found some complex dynamical behaviors that seemingly reflect a relaxation-EQ preparation-main shock-relaxation process. In particular, clear spike-like anomalies in both DFA- and HFD-exponents some months before the main shock are revealed

    MASSIV: Mass Assembly Survey with SINFONI in VVDS. III. Evidence for positive metallicity gradients in z~1.2 star-forming galaxies

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    A key open issue for galaxy evolution and formation models is the understanding of the different mechanisms of galaxy assembly at various cosmic epochs. The aim of this study is to derive the global and spatially-resolved metal content in high-redshift galaxies. Using VLT/SINFONI IFU spectroscopy of a first sample of 50 galaxies at z~1.2 in the MASSIV survey, we are able to measure the Ha and [NII]6584 emission lines. Using the N2 ratio as a proxy for oxygen abundance in the interstellar medium, we measure the metallicity of the sample galaxies. We develop a tool to extract spectra in annular regions of these galaxies, leading to a spatially-resolved estimate of the oxygen abundance in each galaxy. We derive a metallicity gradient for 26 galaxies in our sample and discover a significant fraction of galaxies with a "positive" gradient. Using a simple chemical evolution model, we derive infall rates of pristine gas onto the disks. Seven galaxies display a positive gradient at a high confidence level. Four out of these are interacting and one is a chain galaxy. We suggest that interactions might be responsible for shallowing and even inverting the abundance gradient. We also identify two interesting correlations in our sample: a) galaxies with higher gas velocity dispersion have shallower/positive gradients; and b) metal-poor galaxies tend to show a positive gradient whereas metal-rich ones tend to show a negative one. This last observation can be explained by the infall of metal-poor gas into the center of the disks. We address the question of the origin of this infall under the influence of gas flows triggered by interactions and/or cold gas accretion.Comment: 13 pages, 9 figures. Accepted for publication in A&

    Geography and ecology shape the phylogenetic composition of Amazonian tree communities.

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    Aim Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location Amazonia. Taxon Angiosperms (Magnoliids; Monocots; Eudicots). Methods Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions.Na publicação: Joice Ferreira

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Biased-corrected richness estimates for the Amazonian tree flora

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    Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come
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