Search results for "current"
showing 10 items of 2224 documents
Concurrent TMS-fMRI for causal network perturbation and proof of target engagement
2021
The experimental manipulation of neural activity by neurostimulation techniques overcomes the inherent limitations of correlative recordings, enabling the researcher to investigate causal brain-behavior relationships. But only when stimulation and recordings are combined, the direct impact of the stimulation on neural activity can be evaluated. In humans, this can be achieved non-invasively through the concurrent combination of transcranial magnetic stimulation (TMS) with functional magnetic resonance imaging (fMRI). Concurrent TMS-fMRI allows the assessment of the neurovascular responses evoked by TMS with excellent spatial resolution and full-brain coverage. This enables the functional ma…
Banking Crises and Short and Medium Term Output Losses in Developing Countries: The Role of Structural and Policy Variables
2010
The aim of this work is to assess the short and medium term impact of banking crises on developing economies. Using an unbalanced panel of 159 countries from 1970 to 2006, the paper shows that banking crises produce significant output losses, both in the short and in the medium term. The effect depends on structural and policy variables. Output losses are larger for relatively more wealthy economies, characterized by a higher level of financial deepening and larger current account imbalances. Flexible exchange rates, fiscal and monetary policy have been found to be efficient tools to attenuate the effect of the crises. Among banking intervention policies, liquidity support resulted to be th…
Intercurrent factors associated with the development of open-angle glaucoma in The European Glaucoma Prevention Study
2007
Purpose: To evaluate the intercurrent factors for the development of open-angle glaucoma (OAG) in ocular hypertensive patients who were enrolled in the European Glaucoma Prevention Study (EGPS). Design: Randomized, double masked, controlled clinical trial. Methods: setting: Multicenter. study population: A total of 1,077 patients fulfilled a series of inclusion criteria, including intraocular pressure (IOP) 22 to 29 mm Hg, normal and reliable visual fields (VFs) and normal optic disks. intervention: Treatment with dorzolamide or placebo. main outcome measures: Glaucoma-related VF or optic disk changes. Clinical data were collected every six months during a five-year follow-up. Proportional …
In vitro pulsatile and continuous transdermal delivery of buserelin by iontophoresis
1993
Abstract Transdermal delivery of buserelin, a nonapeptide, from hydroxyethylcellulose hydrogel through isolated human stratum comeum was studied. In vitro studies were carried out in a drug release apparatus (DAB 10/USP XII) using self designed rotary disk cells equipped with platinum electrodes. Different forms of current were examined. A pulsatile application of continuous current resulted in a step-like permeation profile. Different on/off ratios (5 min/55 min; 10 min/50 min; 15 min/45 min)) were studied. When continuous non-interrupted current with different current densities (0.1–0.3 mA·cm −2 ) was applied, linear dependence of the final cumulative amount of buserelin on current durati…
A Simulation Analysis of VSM Control for RES plants in a Small Mediterranean Island
2020
The paper presents an application of Virtual Synchronous Machine control for managing inverter-interfaced renewable energy sources in a small Mediterranean island not supplied by the main grid. In the proposed analysis, the island's renewables-based generators area assumed interfaced to the grid by voltage source converters with a swing controller and a vector-current controller with two different options for the reference current for regulating the voltage at the Point of Common Coupling and the active power output. The system, modeled in PScad environment, allows to verify the response of the renewables-based generators with VSM control in the presence of a fault in the grid.
Josephson-based Threshold Detector for Lévy-Distributed Current Fluctuations
2019
We propose a threshold detector for Lévy-distributed fluctuations based on a Josephson junction. The Lévy-noise current added to a linearly ramped bias current results in clear changes in the distribution of switching currents out of the zero-voltage state of the junction. We observe that the analysis of the cumulative distribution function of the switching currents supplies information on both the characteristics' shape parameter α of the Lévy statistics. Moreover, we discuss a theoretical model, which allows characteristic features of the Lévy fluctuations to be extracted from a measured distribution of switching currents. In view of these results, this system can effectively find an appl…
Tunneling junctions of the heavy-fermion superconductor UPd2Al3
1998
Abstract Tunneling spectroscopy on planar Giaever-type junctions is a powerful tool for the investigation of the superconducting state of metals. Since it is possible to prepare high-quality epitaxial thin films of the heavy-fermion compound UPd 2 Al 3 , this method can be used to examine the energy gap of this presumably unconventional superconductor. We prepared cross-junctions consisting of a UPd 2 Al 3 base electrode and a metal counter electrode (Au, Al or Ag). These small area contacts without artificial barriers have only low junction resistances and suffer from irreproducibility. On the other hand, on some of those junctions we observed BCS-like tunneling conductivity. In order to i…
Very large thermophase in ferromagnetic josephson junctions
2014
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Adiabatic transport of Cooper pairs in arrays of Josephson junctions
1999
We have developed a quantitative theory of Cooper pair pumping in gated one-dimensional arrays of Josephson junctions. The pumping accuracy is limited by quantum tunneling of Cooper pairs out of the propagating potential well and by direct supercurrent flow through the array. Both corrections decrease exponentially with the number N of junctions in the array, but give a serious limitation of accuracy for any practical array. The supercurrent at resonant gate voltages decreases with N only as sin(v/N)/N, where v is the Josephson phase difference across the array.
Noise Induced Phenomena in point Josephson junctions
2008
We present the analysis of the mean switching time and its standard deviation of short overdamped Josephson junctions, driven by a direct current and a periodic signal. The effect of noise enhanced stability is investigated. It is shown that fluctuations may both decrease and increase the switching time.