1,159 research outputs found
Estimating a function of the scale parameter in a gamma distribution with bounded variance
Given a gamma population with known shape parameter , we develop a
general theory for estimating a function of the scale parameter
with bounded variance. We begin by defining a sequential sampling
procedure with satisfying some desired condition in proposing the
stopping rule, and show the procedure enjoys appealing asymptotic properties.
After these general conditions, we substitute with specific
functions including the gamma mean, the gamma variance, the gamma rate
parameter, and a gamma survival probability as four possible illustrations. For
each illustration, Monte Carlo simulations are carried out to justify the
remarkable performance of our proposed sequential procedure. This is further
substantiated with a real data study on weights of newly born babies
The interaction between the GÜ subunit of the heterotrimeric G protein complex with calcium binding proteins, AtClo3/RD20, and AtClo7 from Arabidopsis and TaClo3 from wheat, Triticum aestivum
The alpha subunits of heterotrimeric G proteins and calcium binding proteins play important roles in signal transduction and cellular regulation in plants. However, the molecular function of GÜ proteins in plants is still poorly understood. In order to understand the role of GÜ proteins in signaling pathways, the downstream effectors and upstream regulators need to be investigated. Here we report the first study of interactions between a canonical GÜ subunit, GPA1, and calcium binding proteins in plants. Two of these proteins in Arabidopsis are caleosins, RD20/AtClo3 and AtClo7, which are small Ca 2+ binding proteins with single EF hand domains. Interactions between the two calcium binding proteins and On were studied using bimolecular fluorescence complementation (BiFC) in vivo . RD20/AtClo3 and AtClo7 localized to the ER and tonoplast, however interactions between RD20/Clo3 and Clo7 with GÜ were detected in the ER and PM respectively. A similar approach was used to determine the interaction between TaClo3, a homolog of the caleosins, and TaGA3, a GÜ from wheat. Similar to Arabidopsis caleosins, the TaClo3 protein also localized to the ER and tonoplast. Interactions between TaClo3 and TaGA3 were detected by BiFC in Nicotiana benthamiana , though their localization is not clear. Wheat is hexaploid and is expected to contain more than one GÜ. The detection of the five GÜ genes, some of which contain small insertions in the coding region, suggests a diversity of functions among GÜ wheat homologs. The role of proteins is discussed as a basis for future studies
Ballistic Thermal Rectification in Asymmetric Three-Terminal Mesoscopic Dielectric Systems
By coupling the asymmetric three-terminal mesoscopic dielectric system with a
temperature probe, at low temperature, the ballistic heat flux flow through the
other two asymmetric terminals in the nonlinear response regime is studied
based on the Landauer formulation of transport theory. The thermal
rectification is attained at the quantum regime. It is a purely quantum effect
and is determined by the dependence of the ratio
on , the phonon's frequency.
Where and are respectively the
transmission coefficients from two asymmetric terminals to the temperature
probe, which are determined by the inelastic scattering of ballistic phonons in
the temperature probe. Our results are confirmed by extensive numerical
simulations.Comment: 10 pages, 4 figure
A novel inductor for stabilizing the dc link of adjustable speed drive
The DC-link filter which includes a magnetic inductor and a storage capacitor is one of the key parts of adjustable speed drives in the market. It significantly affects the stability, reliability, and power density of the motor-drive system. This paper proposes a novel, variable active inductor to improve the performance of DC links in terms of stability, reliability, size, and cost. In contrast to conventional DC-link magnetic inductors, the variable active inductor is made of power electronic circuits, including active switches, passive filters, and smart controllers, which no longer rely on magnetic material. The demonstration shows that the inductor can emulate the electrical characteristics of the magnetic inductor for filtering harmonics and stabilizing the DC link, meanwhile representing a smaller size, lighter weight, and lower cost compared with a conventional one. Furthermore, this paper proposes a variable inductance control method which is able to adaptively tune the inductance value with the operating conditions of the drive system. The DC link can be stabilized, and high performance can be maintained in both balanced and unbalanced grid voltage conditions. A case study of the proposed variable inductor in a motor drive with a three-phase diode-bridge rectifier as the front end is discussed. Experimental results are given to verify the functionality and effectiveness of the proposed variable inductor
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