1,648 research outputs found
Feasibility of an Incoherent-scatter Radar Aboard the Space Shuttle
The results of a preliminary study to investigate the feasibility of conducting an incoherent scatter radar experiment on board the space shuttle are presented. The results indicate that such an experiment is technically feasible. The more difficult questions to answer are whether the system can be made flexible enough to justify the problems and costs involved. The design parameters and the tradeoffs that are available in the consideration of these questions are evaluated. Some of the more serious limitations pertain to: (1) the presence of ground clutter and F region auroral clutter; (2) available average power; (3) weight and volume associated with required antenna size, transmitter, and energy storage devices; and (4) antenna breakdown associated with high power transmitter problems
On the application of differential phase measurements to study the zonal large scale wave structure (LSWS) in the ionospheric electron content
Double-sided coaxial circuit QED with out-of-plane wiring
Superconducting circuits are well established as a strong candidate platform
for the development of quantum computing. In order to advance to a practically
useful level, architectures are needed which combine arrays of many qubits with
selective qubit control and readout, without compromising on coherence. Here we
present a coaxial circuit QED architecture in which qubit and resonator are
fabricated on opposing sides of a single chip, and control and readout wiring
are provided by coaxial wiring running perpendicular to the chip plane. We
present characterisation measurements of a fabricated device in good agreement
with simulated parameters and demonstrating energy relaxation and dephasing
times of s and s respectively. The architecture
allows for scaling to large arrays of selectively controlled and measured
qubits with the advantage of all wiring being out of the plane.Comment: 4 pages, 3 figures, 1 tabl
Stabilizing the intensity of a wave amplified by a beam of particles
The intensity of an electromagnetic wave interacting self-consistently with a
beam of charged particles as in a free electron laser, displays large
oscillations due to an aggregate of particles, called the macro-particle. In
this article, we propose a strategy to stabilize the intensity by re-shaping
the macro-particle. This strategy involves the study of the linear stability
(using the residue method) of selected periodic orbits of a mean-field model.
As parameters of an additional perturbation are varied, bifurcations occur in
the system which have drastic effect on the modification of the self-consistent
dynamics, and in particular, of the macro-particle. We show how to obtain an
appropriate tuning of the parameters which is able to strongly decrease the
oscillations of the intensity without reducing its mean-value
Cu-NMR study on the disordered quantum spin magnet with the Bose-glass ground state
Cu-NMR study has been performed on the disordered spin-gap system
Tl1-xKxCuCl3 In the high-field H > HC=\Delta/\mu_B, where \Delta is the
spin-gap, the hyperfine field becomes extremely inhomogeneous at low
temperatures due to the field-induced magnetic order, indicating that the
ordered spin state must be different from the pure TlCuCl3. In the low field H
< HC, a saturating behavior in the longitudinal nuclear spin relaxation rate
1/T1 was observed at low temperatures, indicating existence of the magnetic
ground state proposed to be Bose-glass phase by Fisher.Comment: RHMF200
Protein fold recognition using HMM–HMM alignment and dynamic programming
Detecting three dimensional structures of protein sequences is a challenging task in biological sciences.
For this purpose, protein fold recognition has been utilized as an intermediate step which helps in
classifying a novel protein sequence into one of its folds. The process of protein fold recognition
encompasses feature extraction of protein sequences and feature identification through suitable classi-
fiers. Several feature extractors are developed to retrieve useful information from protein sequences.
These features are generally extracted by constituting protein’s sequential, physicochemical and evolutionary
properties. The performance in terms of recognition accuracy has also been gradually improved over the last decade. However, it is yet to reach a well reasonable and accepted level. In this work, we first applied HMM–HMM alignment of protein sequence from HHblits to extract profile HMM (PHMM) matrix. Then we computed the distance between respective PHMM matrices using kernalized dynamic
programming. We have recorded significant improvement in fold recognition over the state-of-the-art feature extractors. The improvement of recognition accuracy is in the range of 2.7–11.6% when experimented on three benchmark datasets from Structural Classification of Proteins
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Initial Development toward Non-Invasive Drug Monitoring via Untargeted Mass Spectrometric Analysis of Human Skin.
Drug monitoring is crucial for providing accurate and effective care; however, current methods (e.g., blood draws) are inconvenient and unpleasant. We aim to develop a non-invasive method for the detection and monitoring of drugs via human skin. The initial development toward this aim required information about which drugs, taken orally, can be detected via the skin. Untargeted liquid chromatography-mass spectrometry (LC-MS) was used as it was unclear if drugs, known drug metabolites, or other transformation products were detectable. In accomplishing our aim, we analyzed samples obtained by swabbing the skin of 15 kidney transplant recipients in five locations (forehead, nasolabial area, axillary, backhand, and palm), bilaterally, on two different clinical visits. Untargeted LC-MS data were processed using molecular networking via the Global Natural Products Social Molecular Networking platform. Herein, we report the qualitative detection and location of drugs and drug metabolites. For example, escitalopram/citalopram and diphenhydramine, taken orally, were detected in forehead, nasolabial, and hand samples, whereas N-acetyl-sulfamethoxazole, a drug metabolite, was detected in axillary samples. In addition, chemicals associated with environmental exposure were also detected from the skin, which provides insight into the multifaceted chemical influences on our health. The proof-of-concept results presented support the finding that the LC-MS and data analysis methodology is currently capable of the qualitative assessment of the presence of drugs directly via human skin
Universal trapping scaling on the unstable manifold for a collisionless electrostatic mode
An amplitude equation for an unstable mode in a collisionless plasma is
derived from the dynamics on the two-dimensional unstable manifold of the
equilibrium. The mode amplitude decouples from the phase due to the
spatial homogeneity of the equilibrium, and the resulting one-dimensional
dynamics is analyzed using an expansion in . As the linear growth rate
vanishes, the expansion coefficients diverge; a rescaling
of the mode amplitude absorbs these
singularities and reveals that the mode electric field exhibits trapping
scaling as . The dynamics for
depends only on the phase where is the derivative of the dielectric as
.Comment: 11 pages (Latex/RevTex), 2 figures available in hard copy from the
Author ([email protected]); paper accepted by Physical Review
Letter
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