11,709 research outputs found

    Detection of Change--Points in the Spectral Density. With Applications to ECG Data

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    We propose a new method for estimating the change-points of heart rate in the orthosympathetic and parasympathetic bands, based on the wavelet transform in the complex domain and the study of the change-points in the moments of the modulus of these wavelet transforms. We observe change-points in the distribution for both bands.Comment: proceeding of the workshop 'Fouille de donn\'ees temporelles et analyse de flux de donn\'ees' EGC'2009, january 27, Strasbourg, Franc

    Gravitational radiation from inspiralling compact binaries completed at the third post-Newtonian order

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    The gravitational radiation from point particle binaries is computed at the third post-Newtonian (3PN) approximation of general relativity. Three previously introduced ambiguity parameters, coming from the Hadamard self-field regularization of the 3PN source-type mass quadrupole moment, are consistently determined by means of dimensional regularization, and proved to have the values xi = -9871/9240, kappa = 0 and zeta = -7/33. These results complete the derivation of the general relativistic prediction for compact binary inspiral up to 3.5PN order, and should be of use for searching and deciphering the signals in the current network of gravitational wave detectors.Comment: 4 pages in 2-column format, LaTeX 2e, REVTeX 4, no figur

    Job Turnover, Unemployment and Labor Market Institutions

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    This paper studies the role of labor market institutions on unemployment and on the cyclical properties of job flows. We construct an intertemporal general equilibrium model with search unemployment and endogenous job turnover, and examine the consequences of introducing an unemployment benefit, a firing cost and a downward wage rigidity. The simulations suggest that downward wage rigidities, rather than unemployment benefit or firing cost, may well play a dominant role in explaining both the high unemployment rate and the job flows dynamics of such an economy.Unemployment, Job flows dynamics, Institutions

    Phonon-phonon interactions in transition metals

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    In this paper the phonon self energy produced by anharmonicity is calculated using second order many body perturbation theory for all bcc, fcc and hcp transition metals. The symmetry properties of the phonon interactions are used to obtain an expression for the self energy as a sum over irreducible triplets, very similar to integration in the irreducible part of the Brillouin zone for one particle properties. The results obtained for transition metals shows that the lifetime is on the order of 10^10 s. Moreover the Peierls approximation for the imaginary part of the self energy is shown to be reasonable for bcc and fcc metals. For hcp metals we show that the Raman active mode decays into a pair of acoustic phonons, their wave vector being located on a surface defined by conservation laws.Comment: 14 pages, 3 figure

    Organic ‘compensatory’ osmolytes in osmolarity control and hydration changes in animal cells

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    This paper briefly reviews some aspects of the research on organic solutes in osmolarity control and hydration changes of animal cells. It is concerned with the nature of these solutes, their roles in acclimation to hyperosmotic situations, the control of their concentration, and the sensing and signalling of osmolarity changes

    From Classical State-Swapping to Quantum Teleportation

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    The quantum teleportation protocol is extracted directly out of a standard classical circuit that exchanges the states of two qubits using only controlled-NOT gates. This construction of teleportation from a classically transparent circuit generalizes straightforwardly to d-state systems.Comment: Missing daggers added to Figures 13, 14, and 15. Otherwise this is the version that appeared in Physical Revie

    HRTEM and Molecular Modeling of the MoS 2-Co9 S 8 Interface: Understanding the Promotion Effect in Bulk HDS Catalysts

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    As environmental regulations increase, more selective transition metal sulfide (TMS) catalytic materials for hydrotreating applications are needed. Highly active TMS catalysts become more and more desirable triggering new interest for unsupported Co-promoted MoS2-based systems that have high volumetric activity as reported here. Contrary to the common observation for alumina-supported MoS2-based catalysts, we found in our previous studies with dibenzothiophene (DBT) hydrodesulfurization (HDS) that the catalytic activity is directly proportional to the increase of surface area of the sulfide phases (Co9S8 and MoS2) present in Co-promoted MoS2 unsupported catalysts. This suggests that activity is directly connected with an increase of the contact surface area between the two sulfide phases. Understanding of the nature of the possible interaction between MoS2 and Co9S8 in unsupported catalytic systems is therefore critical in order to get a more generalized overview of the causes for synergy. This has been achieved herein through the detailed characterization by XRD, XPS, and HRTEM of the highly active Co9S8/MoS2 catalyst resulting in a proposed model for a Co9S8/MoS2 interface. This model was then subjected to a DFT analysis to determine a reasonable description of the surface contact region between the two bulk phases. Modelling of the interface shows the creation of open latent vacancy sites on Mo atoms interacting with Co and formation of direct Co-Mo bonds. Strong electron donation from Co to Mo also occurs through the intermediate sulfur atom bonded to both metals while an enhanced metallic character is also found. These changes in coordination and electronic properties are expected to favor a synergetic effect between Co and Mo at the proposed localized interface region between the two bulk MoS2 and Co9S8 phases.CONACYT, Mexico 207997MRTI of UTEP, Cotton Trust UTEPMicrolectronics Research Lab of UT-Austin and Departamento de Educacion y Cultura of Gobierno del Estado de ChihuahuaMicroelectronics Research Cente
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