241,058 research outputs found
Feasiblity study for a 34 GHz (Ka band) gyroamplifier
The feasibility of using a gyroklystron power tube as the final amplifier in a 400 kW CW 34 GHz transmitter on the Goldstone Antenna is investigated. A conceptual design of the gyroklystron and the transmission line connecting it with the antenna feed horn is presented. The performance characteristics of the tube and transmission line are compared to the transmitter requirements for a deep space radar system. Areas of technical risk for a follow-on hardware development program for the gyroklystron amplifier and overmoded transmission line components are discussed
Heat-transfer experiments on a 34-ampere-hour nickel-cadmium cell
measurement of temperature distribution in operating nickel-cadmium electric batterie
System for measuring roundness and concentricity of large tanks
Equipment measures the roundness and concentricity of large, massive tanks. The equipment includes a 34-foot rotary table, a variable reluctance displacement transducer, an electronics console, a digital computer, and a 5-foot plotter used for final data display
Event Reconstruction in the PHENIX Central Arm Spectrometers
The central arm spectrometers for the PHENIX experiment at the Relativistic
Heavy Ion Collider have been designed for the optimization of particle
identification in relativistic heavy ion collisions. The spectrometers present
a challenging environment for event reconstruction due to a very high track
multiplicity in a complicated, focusing, magnetic field. In order to meet this
challenge, nine distinct detector types are integrated for charged particle
tracking, momentum reconstruction, and particle identification. The techniques
which have been developed for the task of event reconstruction are described.Comment: Accepted for publication in Nucl. Instrum. A. 34 pages, 23 figure
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An Atypical Presentation of Cystic Echinococcosis
Cystic echinococcosis (CE) is an infection caused by the Echinococcus granulosus tapeworm. CE generally manifests in the liver, but it may present in any organ. These patients often first present to the emergency department. Mortality over 10 years is significant for those who go undiagnosed. We report the case of a 34-year-old patient who immigrated from Yemen six years earlier. She presented with acute onset dysuria, suprapubic pain, and fever. Imaging revealed a primary multicystic mass on the right renal pole with a secondary lesion in the right hepatic lobe. On further investigation, the patient’s serum was positive for echinococcus antibodies
Generalized-Ensemble Simulations of the Human Parathyroid Hormone Fragment PTH(1-34)
A generalized-ensemble technique, multicanonical sampling, is used to study
the folding of a 34-residue human parathyroid hormone fragment. An all-atom
model of the peptide is employed and the protein-solvent interactions are
approximated by an implicit solvent. Our results demonstrate that
generalized-ensemble simulations are well suited to sample low-energy
structures of such large polypeptides. Configurations with a root-mean-square
deviation (rmsd) to the crystal structure of less than one \AA are found.
Finally, we discuss limitations of our implicit solvent model.Comment: To appear in J. Chem. Phy
OverSketch: Approximate Matrix Multiplication for the Cloud
We propose OverSketch, an approximate algorithm for distributed matrix
multiplication in serverless computing. OverSketch leverages ideas from matrix
sketching and high-performance computing to enable cost-efficient
multiplication that is resilient to faults and straggling nodes pervasive in
low-cost serverless architectures. We establish statistical guarantees on the
accuracy of OverSketch and empirically validate our results by solving a
large-scale linear program using interior-point methods and demonstrate a 34%
reduction in compute time on AWS Lambda.Comment: Published in Proc. IEEE Big Data 2018. Updated version provides
details of distributed sketching and highlights other advantages of
OverSketc
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