Einstein-Weyl structures and Bianchi metrics

We analyse in a systematic way the (non-)compact four dimensional Einstein-Weyl spaces equipped with a Bianchi metric. We show that Einstein-Weyl structures with a Class A Bianchi metric have a conformal scalar curvature of constant sign on the manifold. Moreover, we prove that most of them are conformally Einstein or conformally K\"ahler ; in the non-exact Einstein-Weyl case with a Bianchi metric of the type $VII_0, VIII$ or $IX$, we show that the distance may be taken in a diagonal form and we obtain its explicit 4-parameters expression. This extends our previous analysis, limited to the diagonal, K\"ahler Bianchi $IX$ case.Comment: Latex file, 12 pages, a minor modification, accepted for publication in Class. Quant. Gra

Compact Einstein-Weyl four-dimensional manifolds

We look for four dimensional Einstein-Weyl spaces equipped with a regular Bianchi metric. Using the explicit 4-parameters expression of the distance obtained in a previous work for non-conformally-Einstein Einstein-Weyl structures, we show that only four 1-parameter families of regular metrics exist on orientable manifolds : they are all of Bianchi $IX$ type and conformally K\"ahler ; moreover, in agreement with general results, they have a positive definite conformal scalar curvature. In a Gauduchon's gauge, they are compact and we obtain their topological invariants. Finally, we compare our results to the general analyses of Madsen, Pedersen, Poon and Swann : our simpler parametrisation allows us to correct some of their assertions.Comment: Latex file, 13 pages, an important reference added and a critical discussion of its claims offered, others minor modification

Progressive Filtering Using Multiresolution Histograms for Query by Humming System

The rising availability of digital music stipulates effective categorization and retrieval methods. Real world scenarios are characterized by mammoth music collections through pertinent and non-pertinent songs with reference to the user input. The primary goal of the research work is to counter balance the perilous impact of non-relevant songs through Progressive Filtering (PF) for Query by Humming (QBH) system. PF is a technique of problem solving through reduced space. This paper presents the concept of PF and its efficient design based on Multi-Resolution Histograms (MRH) to accomplish searching in manifolds. Initially the entire music database is searched to obtain high recall rate and narrowed search space. Later steps accomplish slow search in the reduced periphery and achieve additional accuracy. Experimentation on large music database using recursive programming substantiates the potential of the method. The outcome of proposed strategy glimpses that MRH effectively locate the patterns. Distances of MRH at lower level are the lower bounds of the distances at higher level, which guarantees evasion of false dismissals during PF. In due course, proposed method helps to strike a balance between efficiency and effectiveness. The system is scalable for large music retrieval systems and also data driven for performance optimization as an added advantage.Comment: 12 Pages, 6 Figures, Full version of the paper published at ICMCCA-2012 with the same title, Link:http://link.springer.com/chapter/10.1007/978-81-322-1143-3_2

Metabolomic Profiling of Aqueous Humor in Glaucoma Points to Taurine and Spermine Deficiency: Findings from the Eye-D Study

We compared the metabolomic profile of aqueous humor from patients with primary open-angle glaucoma (POAG; n = 26) with that of a group of age- and sex-matched non-POAG controls (n = 26), all participants undergoing cataract surgery. Supervised paired partial least-squares discriminant analysis showed good predictive performance for test sets with a median area under the receiver operating characteristic of 0.89 and a p-value of 0.0087. Twenty-three metabolites allowed discrimination between the two groups. Univariate analysis after the Benjamini-Hochberg correction showed significant differences for 13 of these metabolites. The POAG metabolomic signature indicated reduced concentrations of taurine and spermine and increased concentrations of creatinine, carnitine, three short-chain acylcarnitines, 7 amino acids (glutamine, glycine, alanine, leucine, isoleucine, hydroxyl-proline, and acetyl-ornithine), 7 phosphatidylcholines, one lysophosphatidylcholine, and one sphingomyelin. This suggests an alteration of metabolites involved in osmoprotection (taurine and creatinine), neuroprotection (spermine, taurine, and carnitine), amino acid metabolism (7 amino acids and three acylcarnitines), and the remodeling of cell membranes drained by the aqueous humor (hydroxyproline and phospholipids). Five of these metabolic alterations, already reported in POAG plasma, concern spermine, C3 and C4 acylcarnitines, PC aa 34:2, and PC aa 36:4, thus highlighting their importance in the pathogenesis of glaucoma

Corrosion in MEA units for CO2 capture: Pilot plant studies

AbstractAmong the technologies that are under study for CO2 capture from flue gas, the separation process using monoethanolamine (MEA) could be the first to be available for immediate industrial applications in the next few years. The principles of CO2 separation using alkanolamines were discovered nearly a century ago. The process has been applied successfully for several decades in areas such as natural gas processing or coal gasification. The application to flue gas treatment was introduced in the early 1980s, but was not widespread.In such industrial processes, corrosion represents one of the major operational problems. For the capture of CO2 from flue gas using MEA, the problem is even more critical since (i) MEA is one of the most corrosive amine when compared to secondary or tertiary amines that are also used for gas sweetening, and (ii) flue gas contains a certain amount of oxygen, which can react with the amine to form corrosive degradation products.In the framework of the CAPRICE project, which is an International cooperation and exchange project supported by the EU, The International Test centre for CO2 Capture from the University of Regina (CA) and IFP (F) have shared their experience on corrosion monitoring from CO2 capture pilot plants. The first pilot plant facility is owned by ITC. It has a capacity to capture 1 ton CO2/day from a natural gas burner. It is equipped with corrosion control instruments and other monitoring systems. The second pilot plant is located in a coal fired power station in Esbjerg (DK). It was built with the financial support of the UE through the CASTOR project under the lead of IFP. It has been in operation since early 2006, and has a capacity of 1.0 ton CO2/hour. It is equipped with weight loss coupons for corrosion evaluation at different locations in the process.This paper presents the major results of corrosion testing from both pilot plants under MEA operation. It appeared from both pilot plants that the areas most susceptible to corrosion were the stripper inlet and outlet, with corrosion rates around 1 mm.year−1 for carbon steel

Neutron Diffuse Scattering from Polar Nanoregions in the Relaxor Pb(Mg1/3Nb2/3)O3

We have studied the neutron diffuse scattering in the relaxor PMN. The diffuse scattering appears around the Burns temperature (~620K), indicating its origin from the polar nanoregions (PNR). While the relative diffuse intensities are consistent with previous reports, they are entirely different from those of the lowest-energy TO phonon. Because of that, it has been considered that this TO mode could not be the ferroelectric soft mode. Recently, a neutron scattering study has unambiguously shown that the TO mode does soften on cooling. If the diffuse scattering in PMN originates from the soft mode condensation, then the atomic displacements must satisfy the center of mass condition. But, the atomic displacements determined from diffuse scattering intensities do not fulfill this condition. To resolve this contradiction, we propose a simple model in which the total atomic displacement consists of two components: $\delta_{CM}$ is created by the soft mode condensation, satisfying the center of mass condition, and, $\delta_{shift}$ represents a uniform displacement of the PNR along their polar direction relative to the surrounding (unpolarized) cubic matrix. Within this framework, we can successfully describe the neutron diffuse scattering intensities observed in PMN.Comment: 7 pages, 7 figures (Revised: 11-16-2001

The addition of ketone bodies alleviates mitochondrial dysfunction by restoring complex I assembly in a MELAS cellular model

Ketogenic Diet used to treat refractory epilepsy for almost a century may represent a treatment option for mitochondrial disorders for which effective treatments are still lacking. Mitochondrial complex I deficiencies are involved in a broad spectrum of inherited diseases including Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes syndrome leading to recurrent cerebral insults resembling strokes and associated with a severe complex I deficiency caused by mitochondrial DNA (mtDNA) mutations. The analysis of MELAS neuronal cybrid cells carrying the almost homoplasmic m.3243A>G mutation revealed a metabolic switch towards glycolysis with the production of lactic acid, severe defects in respiratory chain activity and complex I disassembly with an accumulation of assembly intermediates. Metabolites, NADH/NAD ratio, mitochondrial enzyme activities, oxygen consumption and BN-PAGE analysis were evaluated in mutant compared to control cells. A severe complex I enzymatic deficiency was identified associated with a major complex I disassembly with an accumulation of assembly intermediates of 400kDa. We showed that Ketone Bodies (KB) exposure for 4weeks associated with glucose deprivation significantly restored complex I stability and activity, increased ATP synthesis and reduced the NADH/NAD+ ratio, a key component of mitochondrial metabolism. In addition, without changing the mutant load, mtDNA copy number was significantly increased with KB, indicating that the absolute amount of wild type mtDNA copy number was higher in treated mutant cells. Therefore KB may constitute an alternative and promising therapy for MELAS syndrome, and could be beneficial for other mitochondrial diseases caused by complex I deficiency

Violation of the Cauchy-Schwarz inequality with matter waves

The Cauchy-Schwarz (CS) inequality -- one of the most widely used and important inequalities in mathematics -- can be formulated as an upper bound to the strength of correlations between classically fluctuating quantities. Quantum mechanical correlations can, however, exceed classical bounds.Here we realize four-wave mixing of atomic matter waves using colliding Bose-Einstein condensates, and demonstrate the violation of a multimode CS inequality for atom number correlations in opposite zones of the collision halo. The correlated atoms have large spatial separations and therefore open new opportunities for extending fundamental quantum-nonlocality tests to ensembles of massive particles.Comment: Final published version (with minor changes). 5 pages, 3 figures, plus Supplementary Materia