3,265 research outputs found
Finite elements numerical solution of a coupled profile–velocity–temperature shallow ice sheet approximation model
AbstractThis work deals with the numerical solution of a complex mathematical model arising in theoretical glaciology. The global moving boundary problem governs thermomechanical processes jointly with ice sheet hydrodynamics. One major novelty is the inclusion of the ice velocity field computation in the framework of the shallow ice model so that it can be coupled with profile and temperature equations. Moreover, the proposed basal velocity and shear stress laws allow the integration of basal sliding effects in the global model. Both features were not taking into account in a previous paper (Math. Model. Methods Appl. Sci. 12 (2) (2002) 229) and provide more realistic convective terms and more complete Signorini boundary conditions for the thermal problem. In the proposed numerical algorithm, one- and two-dimensional piecewise linear Lagrange finite elements in space and a semi-implicit upwinding scheme in time are combined with duality and Newton's methods for nonlinearities. A simulation example involving real data issued from Antarctic shows the temperature, profile and velocity qualitative behaviour as well as the free boundaries and basal effects
Peroxisome proliferator-activated receptor β/δ activation inhibits hypertrophy in neonatal rat cardiomyocytes
Objective: Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) is the predominant PPAR subtype in cardiac cells and plays a prominent role in the regulation of cardiac lipid metabolism. However, the role of PPARβ/δ activators in cardiac hypertrophy is not yet known. Methods and Results: In cultured neonatal rat cardiomyocytes, the selective PPARβ/δ activator L-165041 (10 μmol/L) inhibited phenylephrine (PE)-induced protein synthesis ([3H]leucine uptake), induction of the fetal-type gene atrial natriuretic factor (ANF) and cardiac myocyte size. Induction of cardiac hypertrophy by PE stimulation also led to a reduction in the transcript levels of both muscle-type carnitine palmitoyltransferase (50%, P<0.05) and pyruvatedehydrogenase kinase 4 (30%, P<0.05), and these changes were reversed in the presence of the PPARβ/δ agonist L-165041. Stimulation of neonatal rat cardiomyocytes with PE and embryonic rat heart-derived H9c2 cells with lipopolysaccharide (LPS) enhanced the expression of the nuclear factor (NF)-κB-target gene monocyte chemoattractant protein 1 (MCP-1). The induction of MCP-1 was reduced in the presence of L-165041, suggesting that this compound prevented NF-κB activation. Electrophoretic mobility shift assay (EMSA) revealed that L-165041 significantly decreased LPS-stimulated NF-κB binding activity in H9c2 myotubes. Finally, coimmunoprecipitation studies showed that L-165041 strongly enhanced the physical interaction between PPARβ/δ and the p65 subunit of NF-κB, suggesting that increased association between these two proteins is the mechanism responsible for antagonizing NF-κB activation by PPARβ/δ activators. Conclusion: These results suggest that PPARβ/δ activation inhibits PE-induced cardiac hypertrophy and LPS-induced NF-κB activatio
In situ optimization methodology for ground source heat pump systems: Upgrade to ensure user comfort
[EN] Ground source heat pump systems have been proved to be one of the most efficient systems for heating and cooling in buildings. However, an optimal energy performance depends on a good control of the auxiliaries, which stand for an important part of the total energy consumption. The authors previously developed an experimental in situ optimization methodology for the water circulation pumps frequency of ground source heat pump systems when single stage and multi-stage ON/OFF regulation is employed. However, the user comfort was not completely met under extreme weather conditions during summer. This paper presents the upgrading of this energy optimization strategy combining circulation pumps frequency variation and building supply temperature compensation in order to ensure the user comfort while keeping high energy savings. Experimental results show that the user comfort is met by means of this new methodology and the energy savings (33%) are even higher than those obtained with the previous methodology. (C) 2015 Elsevier B.V. All rights reserved.This work was supported by the "Programa de Ayudas de Investigacion y Desarrollo (PAID)" of the Universitat Politecnica de Valencia. This work was also supported by the European FP7 project "Advanced ground source heat pump systems for heating and cooling in Mediterranean climate" (GROUND-MED).Cervera Vázquez, J.; Montagud Montalvá, CI.; Corberán Salvador, JM. (2015). In situ optimization methodology for ground source heat pump systems: Upgrade to ensure user comfort. Energy and Buildings. 109:195-208. https://doi.org/10.1016/j.enbuild.2015.10.026S19520810
Transferring orbital and spin angular momenta of light to atoms
Light beams carrying orbital angular momentum, such as Laguerre-Gaussian
beams, give rise to the violation of the standard dipolar selection rules
during the interaction with matter yielding, in general, an exchange of angular
momentum larger than hbar per absorbed photon. By means of ab initio 3D
numerical simulations, we investigate in detail the interaction of a hydrogen
atom with intense Gaussian and Laguerre-Gaussian light pulses. We analyze the
dependence of the angular momentum exchange with the polarization, the orbital
angular momentum, and the carrier-envelope phase of light, as well as with the
relative position between the atom and the light vortex. In addition, a
quantum-trajectory approach based on the de Broglie-Bohm formulation of quantum
mechanics is used to gain physical insight into the absorption of angular
momentum by the hydrogen atom
An integrated approach to define new plays in mature oil basins: the example from the Middle Magdalena Valley basin (Colombia)
An integrated approach to detect new areas of potential interest associated with stratigraphic traps in mature basins is presented. The study was carried out in the Middle Magdalena Valley basin, Colombia. The workflow integrates outcrop and subsurface interpretationsoffacies,activityoffaults,anddistributionofdepocenters and paleocurrents and makes use of them to construct a threedimensionalexploration-scalegeocellularfaciesmodelofthebasin. The outcrop and well log sedimentological analysis distinguished faciesassociationsofalluvialfan,overbank, floodplain,andchannel fill,thelastoneconstitutingthereservoirrock.Theseismicanalysis showedthattectonicactivitywas coevalwiththedepositionofthe productive units in the basin and that the activity ended earlier (before the middle Miocene) along the western margin than along the eastern margin. Paleogeographic reconstructions depict transverse and longitudinal fluvial systems, alluvial fans adjacent to the activebasinmargins,and floodplainfaciesdominatingthestructural highs and the southwestern depositional limit. These reconstructions provided statistical data (lateral variograms) to construct the model. The exploration-scale facies model depicts the complete structureofthebasininthreedimensionsandthegrossdistribution of the reservoir and seal rocks. The predictive capability of the model was evaluated positively, and the model was employed to detect zones of high channel fill facies probability that form bodies that are isolated or that terminate upward in pinchouts or are truncated bya fault. Our approach canprovehelpfulinimproving general exploration workflows in similar settings
The wideband backend at the MDSCC in Robledo. A new facility for radio astronomy at Q- and K- bands
The antennas of NASA's Madrid Deep Space Communications Complex (MDSCC) in
Robledo de Chavela are available as single-dish radio astronomical facilities
during a significant percentage of their operational time. Current
instrumentation includes two antennas of 70 and 34 m in diameter, equipped with
dual-polarization receivers in K (18 - 26 GHz) and Q (38 - 50 GHz) bands,
respectively. We have developed and built a new wideband backend for the
Robledo antennas, with the objectives (1) to optimize the available time and
enhance the efficiency of radio astronomy in MDSCC; and (2) to tackle new
scientific cases impossible to that were investigated with the old, narrow-band
autocorrelator. The backend consists of an IF processor, a FFT spectrometer
(FFTS), and the software that interfaces and manages the events among the
observing program, antenna control, the IF processor, the FFTS operation, and
data recording. The whole system was end-to-end assembled in August 2011, at
the start of commissioning activities, and the results are reported in this
paper. Frequency tunings and line intensities are stable over hours, even when
using different synthesizers and IF channels; no aliasing effects have been
measured, and the rejection of the image sideband was characterized. The first
setup provides 1.5 GHz of instantaneous bandwidth in a single polarization,
using 8192 channels and a frequency resolution of 212 kHz; upgrades under way
include a second FFTS card, and two high-resolution cores providing 100 MHz and
500 MHz of bandwidth, and 16384 channels. These upgrades will permit
simultaneous observations of the two polarizations with instantaneous
bandwidths from 100 MHz to 3 GHz, and spectral resolutions from 7 to 212 kHz.Comment: 9 pages, 8 figures. Accepted to Astronomy and Astrophysic
Scaf1 promotes respiratory supercomplexes and metabolic efficiency in zebrafish
The oxidative phosphorylation (OXPHOS) system is a dynamic
system in which the respiratory complexes coexist with superassembled quaternary structures called supercomplexes (SCs). The
physiological role of SCs is still disputed. Here, we used zebrafish
to study the relevance of respiratory SCs. We combined immunodetection analysis and deep data-independent proteomics to
characterize these structures and found similar SCs to those
described in mice, as well as novel SCs including III2 + IV2, I + IV,
and I + III2 + IV2. To study the physiological role of SCs, we generated two null allele zebrafish lines for supercomplex assembly
factor 1 (scaf1). scaf1 / fish displayed altered OXPHOS activity
due to the disrupted interaction of complexes III and IV. scaf1 /
fish were smaller in size and showed abnormal fat deposition and
decreased female fertility. These physiological phenotypes were
rescued by doubling the food supply, which correlated with
improved bioenergetics and alterations in the metabolic gene
expression program. These results reveal that SC assembly by Scaf1
modulates OXPHOS efficiency and allows the optimization of
metabolic resources.Microscopy Imaging Center of the University of BernSpanish Ministry of Economy and Competitiveness, MINECO
SAF2015-65633-RSpanish Ministry of Economy and Competitiveness, MINECO
SAF2015-65633-RHuman Frontier Science Program
RGP0016/2018European Research Council (ERC)
337703SNF
31003A-159721Swiss National Science Foundation (SNSF)
320030_170062MINECO
BIO2015-67580-PCarlos III Institute of Health-Fondo de Investigacion Sanitaria)
PRB3
IPT17/0019Fundacion La Marato TV3La Caixa Foundation
HR17-00247Ministry of Economy, Industry and Competitiveness (MEIC)Pro-CNIC FoundationSevero Ochoa Center of Excellence (MEIC award)
SEV-2015-050
Ruta geomonumental: materiales de construcción utilizados en el Monasterio de Santa María de Pelayos de la Presa y antiguas canteras explotadas para la extracción de la piedra granítica (Madrid).
9 págs, 8 figuras.-- Itinerario incluido entre las actividades de divulgación y comunicación social de la Semana de la Ciencia y la Tecnología en el CSIC (Consejo Superior de Investigaciones Científicas, Nov 2010): http://www.madrimasd.org/semanaciencia/2010/.-- Texto correspondiente a la memoria entregada a los participantes que asistieron a la ruta geomonumentalLas Rutas Geomonumentales suponen una metodología diferente para la difusión cultural y científica del patrimonio arquitectónico, atendiendo a los materiales pétreos, naturales y artificiales, que lo configuran. El prefijo “Geo” indica el fuerte condicionante geológico que tradicionalmente ha influido en los asentamientos urbanos y en su desarrollo, así como la relación existente entre la arquitectura y la geología, en tanto que gran parte de los materiales de construcción se extraen de la tierra. Además, el comportamiento y deterioro de los materiales pétreos está en gran parte condicionado por el entorno que rodea a los inmuebles que constituyen. El Monasterio de Pelayos de la Presa resulta un inmueble ideal para realizar una Ruta Geomonumental como la que se propone. Por un lado, para la construcción del monasterio se utilizaron muy diversos materiales pétreos de construcción (naturales y artificiales) y su emplazamiento en gran parte estuvo condicionado por la existencia de canteras de granito en la zona. Por otro, el estado de conservación que presenta el inmueble, posibilita atender a interesantes aspectos constructivos y a formas de deterioro sufridas por los materiales, así como a las causas que las generan.Peer reviewe
Inhibition of Cardiac Hypertrophy by Triflusal (4-Trifluoromethyl Derivative of Salicylate) and Its Active Metabolite
ABSTRACT The nuclear factor (NF)-B signaling pathway is an important intracellular mediator of cardiac hypertrophy. The aim of the present study was to determine whether triflusal (2-acetoxy-4-trifluoromethylbenzoic acid), a salicylate derivative used as antiplatelet agent, and its active metabolite 2-hydroxy-4-trifluoromethylbenzoic acid (HTB) inhibit cardiac hypertrophy in vitro and in vivo by blocking the NF-B signaling pathway. In cultured neonatal rat cardiomyocytes, HTB (300 M, a concentration reached in clinical use) inhibited phenylephrine (PE)-induced protein synthesis ([ 3 H]leucine uptake), induction of the fetal-type gene atrial natriuretic factor (ANF), and sarcomeric disorganization. Assessment of the effects of triflusal in pressure overload-induced cardiac hypertrophy by aortic banding resulted in a significant reduction in the ratio of heart weight to body weight and in a reduction of the mRNA levels of the cardiac hypertrophy markers ANF and ␣-actinin compared with untreated banded rats. Electrophoretic mobility shift assay revealed an increase in the NF-B binding activity in cardiac nuclear extracts of banded rats that was prevented by triflusal treatment. It is noteworthy that banded rats treated with oral triflusal, compared with untreated rats, showed enhanced protein levels of IB␣, which forms a cytoplasmic inactive complex with the p65-p50 heterodimeric complex. Finally, HTB increased phospho-IB␣ levels in neonatal cardiomyocytes and inhibited proteosome activity, suggesting that this drug prevented proteosome-mediated degradation of IB␣. These results indicate that triflusal, a drug with a well characterized pharmacological and safety profile currently used as antiplatelet, inhibits cardiomyocyte growth by interfering with the NF-B signaling pathway through a post-transcriptional mechanism involving reduced-proteosome degradation of IB␣. Cardiac hypertrophy is a response of the heart to a wide range of extrinsic stimuli, such as arterial hypertension, valvular heart disease, myocardial infarction, and cardiomyopathy. Although this process is initially compensatory for an increase workload, its prolongation frequently results in congestive heart failure, arrhythmia, and sudden deat
- …