2,681 research outputs found

    Trends in velocity and policy expectations

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    U.S. velocity of base money exhibits three distinct trends since 1950. After rising steadily for thirty years, it flattens out in the 1980s and falls substantially in the 1990s. This paper explores whether the observed secular movements in velocity can be accounted for exclusively by endogenous responses to changing expectations about monetary and fiscal policy. We use a model with two key features: a substitute for money in transactions and an array of assets that includes money, nominal bonds, and physical capital. The model maps policy expectations into portfolio decisions, making equilibrium velocity a function of expected future money growth, tax rates, and government spending. When expectations are estimated using Bayesian updating, simulated velocity matches the trends in actual velocity surprisingly well.Macroeconomics ; Money supply ; Monetary policy ; Velocity of money

    Zero Field precession and hysteretic threshold currents in spin torque oscillators with tilted polarizer

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    Using non-linear system theory and numerical simulations we map out the static and dynamic phase diagram in zero applied field of a spin torque oscillator with a tilted polarizer (TP-STO).We find that for sufficiently large currents, even very small tilt angles (beta>1 degree) will lead to steady free layer precession in zero field. Within a rather large range of tilt angles, 1 degree< beta <19 degree, we find coexisting static states and hysteretic switching between these using only current. In a more narrow window (1 degree<beta<5 degree) one of the static states turns into a limit cycle (precession). The coexistence of static and dynamic states in zero magnetic field is unique to the tilted polarizer and leads to large hysteresis in the upper and lower threshold currents for TP-STO operation.Comment: 5 pages, 4 figure

    Exploring Women’s Lived Experiences of Early Marriage in Rural Indonesia

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    Early marriage is still a global concern, and Indonesia ranks second behind Cambodia in the number of early marriages within the ASEAN region. Despite the spread of technology and the influence of Western media, some Indonesian families, especially those who live in rural areas, continue to practice early marriage. Therefore, the purpose of this study was to understand the reasons behind early marriage based on the perspective of Indonesian women who were married before the age of 18. Based on a phenomenological approach, thirty women, ages 18-45, from the Madurese community in Situbondo, East Java participated in the study. Results showed that young Madurese women decided to get married for love and companionship, as well as for economic benefits and protecting the family’s honor. Participants also believed that cultural norms and values related to marriage, sexual purity, and gender expectations play a role in early marriage. Suggestions for future studies and community interventions are discussed

    Model of C-Axis Resistivity of High-\Tc Cuprates

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    We propose a simple model which accounts for the major features and systematics of experiments on the cc-axis resistivity, ρc\rho_c, for \lsco, \ybco and \bsco . We argue that the cc-axis resistivity can be separated into contributions from in-plane dephasing and the cc-axis ``barrier'' scattering processes, with the low temperature semiconductor-like behavior of ρc\rho_c arising from the suppression of the in-plane density of states measured by in-plane magnetic Knight shift experiments. We report on predictions for ρc\rho_c in impurity-doped \ybco materials.Comment: 10 pages + figures, also see March Meeting J13.1

    Magnetic Coherence in Cuprate Superconductors

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    Recent inelastic neutron scattering (INS) experiments on La2x_{2-x}Srx_xCuO4_4 observed a {\it magnetic coherence effect}, i.e., strong frequency and momentum dependent changes of the spin susceptibility, χ\chi'', in the superconducting phase. We show that this effect is a direct consequence of changes in the damping of incommensurate antiferromagnetic spin fluctuations due to the appearance of a d-wave gap in the fermionic spectrum. Our theoretical results provide a quantitative explanation for the weak momentum dependence of the observed spin-gap. Moreover, we predict {\bf (a)} a Fermi surface in La2x_{2-x}Srx_xCuO4_4 which is closed around (π,π)(\pi,\pi) up to optimal doping, and {\bf (b)} similar changes in χ\chi'' for all cuprates with an incommensurate magnetic response.Comment: 5 pages, 4 figures, Fig.3 is in colo

    Doping Dependence of the Magnetic Resonance Peak in YBa_2 Cu_3 O_{6+x}

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    We report inelastic neutron scattering experiments on the doping dependence of the energy and spectral weight of the sharp magnetic resonance peak in YBa_2 Cu_3 O_{6+x}. These measurements also shed light on the relationship between the magnetic excitations in the normal and superconducting states.Comment: (mostly corrections to figures and minor change to caption in Fig.5) 5 figures. It will be published in the proceedings of M2S-HTSC-V. It needs the elsevier style file (not included) to convert to postscrip

    Inhibition of P-Glycoprotein by HIV Protease Inhibitors Increases Intracellular Accumulation of Berberine in Murine and Human Macrophages

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    Background HIV protease inhibitor (PI)-induced inflammatory response in macrophages is a major risk factor for cardiovascular diseases. We have previously reported that berberine (BBR), a traditional herbal medicine, prevents HIV PI-induced inflammatory response through inhibiting endoplasmic reticulum (ER) stress in macrophages. We also found that HIV PIs significantly increased the intracellular concentrations of BBR in macrophages. However, the underlying mechanisms of HIV PI-induced BBR accumulation are unknown. This study examined the role of P-glycoprotein (P-gp) in HIV PI-mediated accumulation of BBR in macrophages. Methodology and Principal Findings Cultured mouse RAW264.7 macrophages, human THP-1-derived macrophages, Wild type MDCK (MDCK/WT) and human P-gp transfected (MDCK/P-gp) cells were used in this study. The intracellular concentration of BBR was determined by HPLC. The activity of P-gp was assessed by measuring digoxin and rhodamine 123 (Rh123) efflux. The interaction between P-gp and BBR or HIV PIs was predicated by Glide docking using Schrodinger program. The results indicate that P-gp contributed to the efflux of BBR in macrophages. HIV PIs significantly increased BBR concentrations in macrophages; however, BBR did not alter cellular HIV PI concentrations. Although HIV PIs did not affect P-gp expression, P-gp transport activities were significantly inhibited in HIV PI-treated macrophages. Furthermore, the molecular docking study suggests that both HIV PIs and BBR fit the binding pocket of P-gp, and HIV PIs may compete with BBR to bind P-gp. Conclusion and Significance HIV PIs increase the concentration of BBR by modulating the transport activity of P-gp in macrophages. Understanding the cellular mechanisms of potential drug-drug interactions is critical prior to applying successful combinational therapy in the clinic

    Probing vertically graded anisotropy in FePtCu films

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    Field-dependent polarized neutron reflectivity (PNR) and magnetometry are employed to study the magnetic properties of compositionally uniform and graded FePtCu films as a function of annealing temperature (TA). The PNR results are able to directly probe the compositional and anisotropy variations through the film thickness. Further details about how the reversal mechanisms evolve are then elucidated by using a first-order reversal curve technique. The reversal of the graded sample annealed at 300º C occurs by an initial rapid switching of the dominant soft A1 phase toward the surface of the film, followed by the gradual reversal of the residual hard phase components toward the bottom. This indicates that the anisotropy gradient is not well established at this low TA. A fundamentally different mechanism is found after annealing at 400ºC, where the rapid switching of the entire film is preceded by a gradual reversal of the soft layers. This suggests that the anisotropy gradient has become better established through the film thickness. The field-dependent PNR measurements confirm the existence of an anisotropy gradient, where the lower (higher) anisotropy portions are now toward the bottom (top) of the film because of the Cu compositional gradient. However, after annealing at 500º C,a single rapid reversal is found, indicating the formation of a uniform hard film. In this case, PNR demonstrates a more uniform magnetic depth profile that is consistent with a uniform reference sample, suggesting significant interdiffusion of the Cu is degrading the compositional and induced anisotropy gradient at this elevated TA
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