7,752 research outputs found

    Approximate Sum Rules of CKM Matrix Elements from Quasi-Democratic Mass Matrices

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    To extract sum rules of CKM matrix elements, eigenvalue problems for quasi-democratic mass matrices are solved in the first order perturbation approximation with respect to small deviations from the democratic limit. Mass spectra of up and down quark sectors and the CKM matrix are shown to have clear and distinctive hierarchical structures. Numerical analysis shows that the absolute values of calculated CKM matrix elements fit the experimental data quite well. The order of the magnitude of the Jarlskog parameter is estimated by the relation J2(mc/mt+ms/mb)Vus2Vcb/4|J| \approx \sqrt{2}(m_c/m_t + m_s/m_b)|V_{us}|^2|V_{cb}|/4.Comment: Latex, 15 pages, no figure

    The cross-frequency mediation mechanism of intracortical information transactions

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    In a seminal paper by von Stein and Sarnthein (2000), it was hypothesized that "bottom-up" information processing of "content" elicits local, high frequency (beta-gamma) oscillations, whereas "top-down" processing is "contextual", characterized by large scale integration spanning distant cortical regions, and implemented by slower frequency (theta-alpha) oscillations. This corresponds to a mechanism of cortical information transactions, where synchronization of beta-gamma oscillations between distant cortical regions is mediated by widespread theta-alpha oscillations. It is the aim of this paper to express this hypothesis quantitatively, in terms of a model that will allow testing this type of information transaction mechanism. The basic methodology used here corresponds to statistical mediation analysis, originally developed by (Baron and Kenny 1986). We generalize the classical mediator model to the case of multivariate complex-valued data, consisting of the discrete Fourier transform coefficients of signals of electric neuronal activity, at different frequencies, and at different cortical locations. The "mediation effect" is quantified here in a novel way, as the product of "dual frequency RV-coupling coefficients", that were introduced in (Pascual-Marqui et al 2016, http://arxiv.org/abs/1603.05343). Relevant statistical procedures are presented for testing the cross-frequency mediation mechanism in general, and in particular for testing the von Stein & Sarnthein hypothesis.Comment: https://doi.org/10.1101/119362 licensed as CC-BY-NC-ND 4.0 International license: http://creativecommons.org/licenses/by-nc-nd/4.0

    Transmission Spectroscopy of Molecular Spin Ensembles in the Dispersive Regime

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    The readout in the dispersive regime is originally developed—and it is now largely exploited—for non-demolitive measurement of super- and semiconducting qubits. More recently it has been successfully applied to probe collective spin excitations in ferro(i)magnetic bulk samples or collections of paramagnetic spin centers embedded into microwave cavities. The use of this readout technique within a semiclassical limit of excitation is only marginally investigated although it holds for a wide class of problems, including advanced magnetic resonance techniques. In this work, the coupling between a coplanar microwave resonator and diphenyl-nitroxide organic radical diluted in a fully deuterated benzophenone single crystal is investigated. Two-tone transmission spectroscopy experiments demonstrate the possibility to reconstruct the spectrum of the spin system with little loss of sensitivity with respect to the resonant regime. Likewise, pulse sequences of detuned microwave frequency allow the measurement of the spin-lattice relaxation time (T1). The independent tunability of the probe and the drive power enables one to adjust the signal-to-noise ratio of the spectroscopy. These results suggest that electron spin dispersive spectroscopy can be used as a complementary tool of electron spin resonance to investigate the spin response

    A Phase-Space Approach to Collisionless Stellar Systems Using a Particle Method

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    A particle method for reproducing the phase space of collisionless stellar systems is described. The key idea originates in Liouville's theorem which states that the distribution function (DF) at time t can be derived from tracing necessary orbits back to t=0. To make this procedure feasible, a self-consistent field (SCF) method for solving Poisson's equation is adopted to compute the orbits of arbitrary stars. As an example, for the violent relaxation of a uniform-density sphere, the phase-space evolution which the current method generates is compared to that obtained with a phase-space method for integrating the collisionless Boltzmann equation, on the assumption of spherical symmetry. Then, excellent agreement is found between the two methods if an optimal basis set for the SCF technique is chosen. Since this reproduction method requires only the functional form of initial DFs but needs no assumptions about symmetry of the system, the success in reproducing the phase-space evolution implies that there would be no need of directly solving the collisionless Boltzmann equation in order to access phase space even for systems without any special symmetries. The effects of basis sets used in SCF simulations on the reproduced phase space are also discussed.Comment: 16 pages w/4 embedded PS figures. Uses aaspp4.sty (AASLaTeX v4.0). To be published in ApJ, Oct. 1, 1997. This preprint is also available at http://www.sue.shiga-u.ac.jp/WWW/prof/hozumi/papers.htm

    ARSENIC REMOVAL FROM GROUNDWATER USING INDIGENOUS IRON AND MANGANESE OXDIZING BACTERIA

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    Joint Research on Environmental Science and Technology for the Eart

    Underwater 3D Scanner Using RGB Laser Pattern

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    For efficiency surveying fishery resource, the authors developed the scanner which measure the target shape at once time. The scanner based on the structured light method irradiated the laser patter coded on De Bruijn for high resolution the measurement under water. The evaluation experiment results showed that the scanner can measure the target shape less than 1.4 % error for the measurement range.2021 IEEE/SICE International Symposium on System Integration (SII 2021), January 11-14, 2021, Iwaki, Fukushima, Japan (Virtual Conference

    Radiomitigative Effects of Approved Hematopoietic Drugs on Mice Exposed to Lethal Total-body Irradiation

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    In cases of radiological accidents, especially for victims exposed to high-dose total-body irradiation (TBI), the administration of appropriate approved hematopoietic drugs is the most rapid medical treatment for preventing severe acute radiation syndrome, which is associated with a high mortality rate. However, at present, there are few suitable pharmaceutical drugs available in Japan, aside from granulocyte colony-stimulating factor (G-CSF). Depending on the situation surrounding the accident, various drug treatment options and the development of effective drug therapies may be required. In the present study, we assessed various combinations of seven commercially available drugs-G-CSF, erythropoietin (EPO), romiplostim (RP), ancer (AN), cepharanthine (CE), leucon (LC) and leukoprol (LP)-in mice exposed to a lethal dose of 7 or 8 Gy of X-ray irradiation. Each drug was administered as a single or mixed intraperitoneal injection once or twice daily for three consecutive days. The single administration of the approved hematopoietic drugs CE, LC, or LP twice a day for 3 days significantly improved the 30-day survival rate of lethal TBI mice (p < 0.05; 75%, 100%, or 100%, respectively) compared with the untreated TBI mice, accompanied by a gradual increase in the body weight. Furthermore, the combined administration of RP, EPO and G-CSF or single administration of RP alone gradually increased the body weight of mice exposed to lethal TBI, with 30-day survival rates of 75% or 100%, respectively (p < 0.05). This study suggested that some new domestically approved hematopoietic drugs may have radiomitigative potential for mice exposed to lethal TBI, and the 12-h interval administration of LC or LP for 3 days to 7-Gy-TBI mice and 12-h interval administration of RP alone for 3 days to 8-Gy-TBI mice were the most suitable medications with respect to the 30-day survival rate. As long as the threat of nuclear disaster exists, diverse efforts in thefield of radiation emergency medicine, including the development of effective drug therapies, will be necessary
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