1,733 research outputs found
Gravity Anomalies, Geodynamic Modelling and the Eastern Venezuela Basin Evolution.
This work examines the tectonic evolution of the Eastern Venezuela foreland basin by analysis of gravity anomalies and geodynamical modelling. Gravity data (8ÂșN-12ÂșN and 60ÂșW-66ÂșW) were processed to produce gravity anomaly maps, the most prominent feature being the minimum of -200 mGal isostatic, Bouguer and free-air anomalies associated with the basin. Positive gravity values characterize the northern terranes. Backstripping analysis of the sedimentary successions of four boreholes penetrating the Eastern Venezuela basin was applied to evaluate the history of subsidence. This demonstrated that an early passive margin phase (Cretaceous to early Oligocene) was followed by Oligocene to Recent tectonic subsidence of the foreland basin linked to the northern coastal compressional tectonic belt. Geohistorical analysis shows a major contribution to subsidence from early Oligocene, renewed during mid-Miocene times, in response to the loading of the South American plate on its northern margin. This tectonic loading pattern is younger from north to south. The observed gravity anomaly paired in eastern Venezuela is adequately reproduced by crustal models along profiles OOÂŽ and IIÂŽ showing the isostatic negative anomaly over the foreland basin, primarily caused by the 10-13 km of sediments, the downwarping of dense lower crust and Moho down to 48 km depth. The positive gravity anomalies to the North are associated with southward thrusting of metamorphic and magmatic terranes, and dense Caribbean lithosphere. Dense subducting mantle may also be contributing to the northern positive anomaly belt as deep seismicity suggests.
Two mechanisms were applied to explain the formation of the Eastern Venezuela foreland basin during a collisional regime. First, the âhidden loadâ approach explains the deflection but includes an intracrustal load whose magnitude is around a third of the supracrustal loads computed by an iterative process. This gives rise to a major misfit between the gravity anomaly computed for the structural model which takes into account all the geological and geophysical constraints when the contribution of the âhidden loadâ is included in the calculations. Second, since the hidden load hypothesis fails to explain the gravity profiles, a remaining viable explanation is release of compressional strain energy involving N-S crustal shortening involving faulting. I therefore explored a fault-based hypothesis which does not depend on hidden gravitational loads, but takes into account the clear relationship between the subsidence and the complementary uplift. In conclusion the prime cause of the evolution of the system depends on the forces on fault planes as they move, where the tractions on a thrust fault develop when a frictionless fault occurs in response to horizontal deviatoric compression of an elastic layer. As compression acts at the edges of the plate, the stresses are re-orientated producing the movement of the two plates along dipping fault planes (including the El Pilar fault). This led to the formation of the Eastern Venezuela foreland basin and linked uplift of the Eastern SerranĂa del Interior by spasmodic release of elastic strain energy
Magnetically-induced ferroelectricity in the (ND4)2[FeCl5(D2O)] molecular compound
The number of magnetoelectric multiferroic materials reported to date is
scarce, as magnetic structures that break inversion symmetry and induce an
improper ferroelectric polarization typically arise through subtle competition
between different magnetic interactions. The (NH4)2[FeCl5(H2O)] compound is a
rare case where such improper ferroelectricity has been observed in a molecular
material. We have used single crystal and powder neutron diffraction to obtain
detailed solutions for the crystal and magnetic structures of
(NH4)2[FeCl5(H2O)], from which we determined the mechanism of multiferroicity.
From the crystal structure analysis, we observed an order-disorder phase
transition related to the ordering of the ammonium counterion. We have
determined the magnetic structure below TN, at 2K and zero magnetic field,
which corresponds to a cycloidal spin arrangement with magnetic moments
contained in the ac-plane, propagating parallel to the c-axis. The observed
ferroelectricity can be explained, from the obtained magnetic structure, via
the inverse Dzyaloshinskii-Moriya mechanism
Liberacion comercial y crecimiento economico en Mercosur 1994-2000
El presente trabajo es un estudio del desarrollo del Mercado Comun del Sur, desde sus antecedentes juridicos y su creacion en 1991 hasta la actualidad, señalando una fecha de referencia (1995), con objeto de analizar los efectos de la entrada en vigor del arancel externo comun en el crecimiento economico del Mercosur, contrastando el "shock" producido por la apertura de sus mercados al exterior, si bien la liberalizacion comercial venia siendo progresiva, de acuerdo al programa de desgravacion arancelaria. This paper studies the evolution of Mercosur, from its regulatory commences and its birth in 1991 to the present day. In order to analyse the effects of the implementation of a common external tariff in 1995 over the economic growth of Mercosur, we tested the shock caused for this policy measure. However, we should take into account that a policy addressed to achieve more international openness of these economies had been being progressively implemented before this date.
Hybrid Control Strategy for Force and Precise End Effector Positioning of a Twisted String Actuator
Funding Agency: Swiss Innovation Agency, InnosuissePeer reviewedPostprin
Quantifying the Performance Enhancement Facilitated by Fractional-Order Implementation of Classical Control Strategies for Nanopositioning
Open Access via the Elsevier/JISC agreementPeer reviewe
Increasing the damping of oscillatory systems with an arbitrary number of time varying frequencies using fractional-order collocated feedback
Acknowledgements: This research was sponsored in part by the Spanish Government Research Program with the project DPI2016-80547-R (Ministerio de EconomĂa y Competitividad), in part by the University of Castilla-La Mancha under Project 2019-GRIN-26969 and in part by the European Social Fund (FEDER, EU).Peer reviewedPublisher PD
Protein Interactions and Nanomaterials: A Key Role of the Protein Corona in Nanobiocompatibility
The protein corona is still somewhat of a mysterious consequence of the nanoparticlesâ application in theranostics. In this review, several critical aspects related to the protein corona are described, in particular which influences more specifically its formation, how to evaluate/characterize it, and what interactions to expect when the nanoparticle and the protein corona are inside the cell. Despite these issues, which have been studied in a general way, it has been verified that thereâs still much information missing when it comes to specific nanoparticles. Here, a few proteins are also highlighted as examples, which have been identified as part of the protein corona; in addition, several factors related to the formation of protein corona are discussed due to their important role in the different adsorbed proteins
Advanced Motor Control for Improving the Trajectory Tracking Accuracy of a Low-Cost Mobile Robot
This research was funded by the Grant PID2019-111278RB-C21 funded by MCIN/AEI/ 10.13039/501100011033 and âERDF A way of making Europeâ.Peer reviewedPublisher PD
Early Surgery with Neuraxial Anaesthesia in Patients on Chronic Antiplatelet Therapy with a Proximal Femur Fracture: Multicentric Randomised Clinical Trial
Medicamentos antiplaquetarios; Fractura de fĂ©mur; Ensayo clĂnico aleatorizadoAntiplatelet drugs; Femur fracture; Randomized clinical trialFĂ rmacs antiagregants plaquetaris; Fractura de fĂšmur; Assaig clĂnic aleatoritzatBackground: Patients with proximal femur fracture on antiplatelet treatment benefit from early surgery. Our goal was to perform early surgery under neuraxial anaesthesia when indicated by the platelet function test. Methods: We conducted a multicentre randomised open-label parallel clinical trial. Patients were randomised to either early platelet function-guided surgery (experimental group) or delayed surgery (control group). Early surgery was programmed when the functional platelet count (as measured by Plateletworks) was >80 Ă 109/L. The primary outcome was the emergency admission-to-surgery interval. Secondary outcomes were platelet function, postoperative bleeding, medical and surgical complications, and mortality. Results: A total of 156 patients were randomised, with 78 in each group, with a mean (SD) age of 85.96 (7.9) years, and 67.8% being female. The median (IQR) time to surgery was 2.3 (1.5â3.7) days for the experimental group and 4.9 (4.4â5.6) days for the control group. One-third of patients did not achieve the threshold functional platelet count on the first day of admission, requiring more than one test. There was no difference in clinical outcomes between groups. Conclusions: A strategy individualised according to the platelet function test shortens the time to proximal femur fracture surgery under neuraxial anaesthesia in patients on chronic antiplatelet treatment. Better powered randomised clinical trials are needed to further evaluate the clinical impact and safety of this strategy.This research was funded by Instituto de Salud Carlos III and European Regional Development Fund (ERDF), âA way to make Europeâ, grant number PI16/01879 and Spanish Clinical Research Network (PT17/0017/0034 and PT20/00096). Biometa Tecnologias y Sistemas (33428 Llanera, Asturias, Spain) partially funded the PLATELETWORKS reagent kits. The sponsor and funders are not involved in study design; collection, management, analysis, and interpretation of data; writing of the report; and the decision to submit the report for publication
Low-optical-loss, low-resistance Ag/Ge based ohmic contacts to n-type InP for membrane based waveguide devices
We present the development of Ag/Ge based ohmic contacts to n-type InP with both low contact resistances and relatively low optical losses. A specific contact resistance as low as 1.5Ă10-6 O cm2 is achieved by optimizing the Ge layer thickness and annealing conditions. The use of Ge instead of metal as the first deposited layer results in a low optical absorption loss in the telecommunication wavelength range. Compared to Au based contacts, the Ag based metallization also shows considerably reduced spiking effects after annealing. Contacts with different lengths are deposited on top of InP membrane waveguides to characterize the optical loss before and after annealing. A factor of 5 reduction of the propagation loss compared to the conventional Au/Ge/Ni contact is demonstrated. This allows for much more optimized designs for membrane photonic devices
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