6,567 research outputs found
Coarse-grained reconfigurable array architectures
Coarse-Grained Reconfigurable Array (CGRA) architectures accelerate the same inner loops that benefit from the high ILP support in VLIW architectures. By executing non-loop code on other cores, however, CGRAs can focus on such loops to execute them more efficiently. This chapter discusses the basic principles of CGRAs, and the wide range of design options available to a CGRA designer, covering a large number of existing CGRA designs. The impact of different options on flexibility, performance, and power-efficiency is discussed, as well as the need for compiler support. The ADRES CGRA design template is studied in more detail as a use case to illustrate the need for design space exploration, for compiler support and for the manual fine-tuning of source code
Comprehensive Solution to Scattering by Bianisotropic Objects of Arbitrary Shape
This paper presents a method of moments (MoM) solution for the problems of electromagnetic scattering by inhomogeneous three- dimensional bianisotropic scatterers of any shape. The electromagnetic response of bianisotropy has been described by the constitutive relations of the most general form composed of four 3 X 3 matrices or tensors. The volume equivalence principle is used to obtain a set of mixed potential formulations for a proper description of the original scattering problem. Here, the total fields are separated into the incident fields and the scattered fields. The scattered fields are related to the electric and magnetic potentials which are excited by electric and magnetic bound charges and polarization currents. The body of the scatterer is meshed through the use of tetrahedral cells with face-based functions used to expand unknown quantities. At last, the Galerkin test method is applied to create a method of moments (MoM) matrix from which the numerical solution is obtained. Implemented in a MATLAB program, the numerical formulation is evaluated and verified for various types of scatterers. The results are compared with those of previous work, and a good agreement is observed. Finally, a scattering from a two-layered dispersive chiroferrite sphere is presented as the most general example
The glucocorticoid-Angptl4-ceramide axis induces insulin resistance through PP2A and PKCζ.
Chronic glucocorticoid exposure is associated with the development of insulin resistance. We showed that glucocorticoid-induced insulin resistance was attenuated upon ablation of Angptl4, a glucocorticoid target gene encoding the secreted protein angiopoietin-like 4, which mediates glucocorticoid-induced lipolysis in white adipose tissue. Through metabolomic profiling, we revealed that glucocorticoid treatment increased hepatic ceramide concentrations by inducing enzymes in the ceramide synthetic pathway in an Angptl4-dependent manner. Angptl4 was also required for glucocorticoids to stimulate the activities of the downstream effectors of ceramide, protein phosphatase 2A (PP2A) and protein kinase Cζ (PKCζ). We further showed that knockdown of PP2A or inhibition of PKCζ or ceramide synthesis prevented glucocorticoid-induced glucose intolerance in wild-type mice. Moreover, the inhibition of PKCζ or ceramide synthesis did not further improve glucose tolerance in Angptl4-/- mice, suggesting that these molecules were major downstream effectors of Angptl4. Overall, our study demonstrates the key role of Angptl4 in glucocorticoid-augmented hepatic ceramide production that induces whole-body insulin resistance
Evolution of surface gravity waves over a submarine canyon
The effects of a submarine canyon on the propagation of ocean surface waves
are examined with a three-dimensional coupled-mode model for wave propagation
over steep topography. Whereas the classical geometrical optics approximation
predicts an abrupt transition from complete transmission at small incidence
angles to no transmission at large angles, the full model predicts a more
gradual transition with partial reflection/transmission that is sensitive to
the canyon geometry and controlled by evanescent modes for small incidence
angles and relatively short waves. Model results for large incidence angles are
compared with data from directional wave buoys deployed around the rim and over
Scripps Canyon, near San Diego, California, during the Nearshore Canyon
Experiment (NCEX). Wave heights are observed to decay across the canyon by
about a factor 5 over a distance shorter than a wavelength. Yet, a spectral
refraction model predicts an even larger reduction by about a factor 10,
because low frequency components cannot cross the canyon in the geometrical
optics approximation. The coupled-mode model yields accurate results over and
behind the canyon. These results show that although most of the wave energy is
refractively trapped on the offshore rim of the canyon, a small fraction of the
wave energy 'tunnels' across the canyon. Simplifications of the model that
reduce it to the standard and modified mild slope equations also yield good
results, indicating that evanescent modes and high order bottom slope effects
are of minor importance for the energy transformation of waves propagating
across depth contours at large oblique angles
Comprehensive Solution to Scattering by Bianisotropic Objects of Arbitrary Shape
This paper presents a method of moments (MoM) solution for the problems of electromagnetic scattering by inhomogeneous three- dimensional bianisotropic scatterers of any shape. The electromagnetic response of bianisotropy has been described by the constitutive relations of the most general form composed of four 3 £ 3 matrices or tensors. The volume equivalence principle is used to obtain a set of mixed potential formulations for a proper description of the original scattering problem. Here, the total ¯elds are separated into the incident ¯elds and the scattered ¯elds. The scattered ¯elds are related to the electric and magnetic potentials which are excited by electric and magnetic bound charges and polarization currents. The body of the scatterer is meshed through the use of tetrahedral cells with face-based functions used to expand unknown quantities. At last, the Galerkin test method is applied to create a method of moments (MoM) matrix from which the numerical solution is obtained. Implemented in a MATLAB program, the numerical formulation is evaluated and veri¯ed for various types of scatterers. The results are compared with those of previous work, and a good agreement is observed. Finally, a scattering from a two-layered dispersive chiroferrite sphere is presented as the most general example
Tactile Sensors Based on Conductive Polymers
This paper presents results from a selection of tactile sensors that have been designed and fabricated. These sensors are based on a common approach that consists in placing a sheet of piezoresistive material on the top of a set of electrodes. We use a thin film of conductive polymer as the piezoresistive mate¬rial. Specifically, a conductive water-based ink of this polymer is deposited by spin coating on a flexible plastic sheet, giving it a smooth, homogeneous and conducting thin film. The main interest in this procedure is that it is cheap and it allows the fabrication of flexible and low cost tactile sensors. In this work we present results from sensors made using two technologies. Firstly, we have used a flexible Printed Circuit Board (PCB) technology to fabricate the set of electrodes and addressing tracks. The result is a simple, flexible tactile sensor. In addition to these sensors on PCB, we have proposed, designed and fabricated sensors with screen printing technology. In this case, the set of electrodes and addressing tracks are made by printing an ink based on silver nanoparticles. The intense characterization provides us insights into the design of these tactile sensors.This work has been partially funded by the spanish government under contract TEC2006-12376-C02
Quantifying Inactive Lithium in Lithium Metal Batteries
Inactive lithium (Li) formation is the immediate cause of capacity loss and
catastrophic failure of Li metal batteries. However, the chemical component and
the atomic level structure of inactive Li have rarely been studied due to the
lack of effective diagnosis tools to accurately differentiate and quantify Li+
in solid electrolyte interphase (SEI) components and the electrically isolated
unreacted metallic Li0, which together comprise the inactive Li. Here, by
introducing a new analytical method, Titration Gas Chromatography (TGC), we can
accurately quantify the contribution from metallic Li0 to the total amount of
inactive Li. We uncover that the Li0, rather than the electrochemically formed
SEI, dominates the inactive Li and capacity loss. Using cryogenic electron
microscopies to further study the microstructure and nanostructure of inactive
Li, we find that the Li0 is surrounded by insulating SEI, losing the electronic
conductive pathway to the bulk electrode. Coupling the measurements of the Li0
global content to observations of its local atomic structure, we reveal the
formation mechanism of inactive Li in different types of electrolytes, and
identify the true underlying cause of low Coulombic efficiency in Li metal
deposition and stripping. We ultimately propose strategies to enable the highly
efficient Li deposition and stripping to enable Li metal anode for next
generation high energy batteries
Circulating microRNAs Reveal Time Course of Organ Injury in a Porcine Model of Acetaminophen-Induced Acute Liver Failure
Acute liver failure is a rare but catastrophic condition which can progress rapidly to multi-organ failure. Studies investigating the onset of individual organ injury such as the liver, kidneys and brain during the evolution of acute liver failure, are lacking. MicroRNAs are short, non-coding strands of RNA that are released into the circulation following tissue injury. In this study, we have characterised the release of both global microRNA and specific microRNA species into the plasma using a porcine model of acetaminophen-induced acute liver failure. Pigs were induced to acute liver failure with oral acetaminophen over 19h±2h and death occurred 13h±3h thereafter. Global microRNA concentrations increased 4h prior to acute liver failure in plasma (P<0.0001) but not in isolated exosomes, and were associated with increasing plasma levels of the damage-associated molecular pattern molecule, genomic DNA (P<0.0001). MiR122 increased around the time of onset of acute liver failure (P<0.0001) and was associated with increasing international normalised ratio (P<0.0001). MiR192 increased 8h after acute liver failure (P<0.0001) and was associated with increasing creatinine (P<0.0001). The increase in miR124-1 occurred concurrent with the pre-terminal increase in intracranial pressure (P<0.0001) and was associated with decreasing cerebral perfusion pressure (P<0.002)
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