5,680 research outputs found
Thermal Mitigation in Mobile Devices
In order to prevent damage and component failure from excess heat in a portable electronic device, thermal mitigation measures often are implemented by a thermal control module of the device. Temperature sensors, such as thermistors, provided with individual components of the device provide temperature information to a processor, which also receives information about the use of the device and its environment. Based on the temperature, usage, and environmental information, the processor determines whether thermal mitigation measures should be implemented to lower the temperature of one or more components to below a threshold and, if so, which mitigation measures to implement in order to do so with minimal impact on the experience of the user of the device
Holonomic quantum computation using rf superconducting quantum interference devices coupled through a microwave cavity
We propose a different scheme to realize holonomic quantum computation with rf superconducting quantum interference device (SQUID) qubits in a microwave cavity. In this scheme associated with the non-Abelian holonomies, the single-qubit gates and a two-qubit controlled-PHASE gate as well as a controlled-NOT gate can be easily constructed by tuning adiabatically the Rabi frequencies of classical microwave pulses coupled to the SQUIDs. The fidelity of these gates is estimated to be possibly higher than 90% with the current technology. © 2005 The American Physical Society.published_or_final_versio
Soft gluon resummation in Higgs boson plus two jet production at the LHC
The soft gluon resummation effect in the Higgs boson plus two-jet production at the LHC is studied by applying the transverse momentum dependent factorization formalism. The large logarithms, introduced by the small total transverse momentum of the Higgs boson plus two-jet final state system, are resummed to all orders in the expansion of the strong interaction coupling with the accuracy of Next-to-Leading Logarithm order. This significantly improves the theoretical prediction. We also compare our result with the prediction of the Monte Carlo event generator Pythia8, and find noticeable difference in the distributions of the total transverse momentum and the azimuthal angle correlations of the final state Higgs boson and two-jet system, when applying similar kinematic cuts used in the LHC data analysis. This difference is large enough to affect the measurement of Higgs boson coupling to the vector boson at the future High luminosity LHC
A Quantile Variant of the EM Algorithm and Its Applications to Parameter Estimation with Interval Data
The expectation-maximization (EM) algorithm is a powerful computational
technique for finding the maximum likelihood estimates for parametric models
when the data are not fully observed. The EM is best suited for situations
where the expectation in each E-step and the maximization in each M-step are
straightforward. A difficulty with the implementation of the EM algorithm is
that each E-step requires the integration of the log-likelihood function in
closed form. The explicit integration can be avoided by using what is known as
the Monte Carlo EM (MCEM) algorithm. The MCEM uses a random sample to estimate
the integral at each E-step. However, the problem with the MCEM is that it
often converges to the integral quite slowly and the convergence behavior can
also be unstable, which causes a computational burden. In this paper, we
propose what we refer to as the quantile variant of the EM (QEM) algorithm. We
prove that the proposed QEM method has an accuracy of while the MCEM
method has an accuracy of . Thus, the proposed QEM method
possesses faster and more stable convergence properties when compared with the
MCEM algorithm. The improved performance is illustrated through the numerical
studies. Several practical examples illustrating its use in interval-censored
data problems are also provided
The effects of rotation on the lithium depletion of G- and K-dwarfs in Messier 35
New fibre spectroscopy and radial velocities from the WIYN telescope are used to measure photospheric lithium in 242 high-probability, zero-age-main-sequence (ZAMS) F- to K-type members of the rich cluster M35. Combining these with published rotation periods, the connection between lithium depletion and rotation is studied in unprecedented detail. At K there is a strong relationship between faster rotation and less Li depletion, although with a dispersion larger than measurement uncertainties. Components of photometrically identified binary systems follow the same relationship. A correlation is also established between faster rotation rate (or smaller Rossby number), decreased Li depletion and larger stellar radius at a given . These results support models where starspots and interior magnetic fields lead to inflated radii and reduced Li depletion during the pre main sequence (PMS) phase for the fastest rotators. However, the data are also consistent with the idea that all stars suffered lower levels of Li depletion than predicted by standard PMS models, perhaps because of deficiencies in those models or because saturated levels of magnetic activity suppress Li depletion equally in PMS stars of similar regardless of rotation rate, and that slower rotators subsequently experience more mixing and post-PMS Li depletion
Dynamic sensitivity of photon-dressed atomic ensemble with quantum criticality
We study the dynamic sensitivity of an atomic ensemble dressed by a single-mode cavity field (called a photon-dressed atomic ensemble), which is described by the Dicke model near the quantum critical point. It is shown that when an extra atom in a pure initial state passes through the cavity, the photon-dressed atomic ensemble will experience a quantum phase transition showing an explicit sudden change in its dynamics characterized by the Loschmidt echo of this quantum critical system. With such dynamic sensitivity, the Dicke model can resemble the cloud chamber for detecting a flying particle by the enhanced trajectory due to the classical phase transition. © 2009 The American Physical Society.published_or_final_versio
Identification of transient receptor potential channels in human atrial myocytes
In Hong Kong Medical Journal, 2011, v. 17, suppl. 1, p. 68, abstract no. 115published_or_final_versionThe 16th Medical Resarch Conference (MRC), The University of Hong Kong, Hong Kong, China, 22 January 2011. In Hong Kong Medical Journal, 2011, v. 17, suppl. 1, p. 68, abstract no. 11
Molecular characterization and expression analysis of a hepcidin gene from rice field eel (Monopterus albus)
Hepcidin is a cysteine-rich, dual-function peptide with antimicrobial activity that plays crucial roles in iron homeostasis. A few hepcidin-like genes have been isolated from teleost. Here, we have identified a hepcidin-like gene from rice field eel (RFE), Monopterus albus. Nucleotide sequences including cDNA and genomic DNA (GenBank accession numbers: FJ436808 and FJ594996, respectively) and deduced amino acid sequences were presented. In the 949 bp-long genomic sequence, two introns and three exons were identified. The full-length cDNA encodes a prepropeptide of 90 amino acid residues. RTPCR analysis suggested that hepcidin transcripts are highly abundant in the liver and kidney, less abundant in the heart, skin, brain, blood cells, intestine, spleen and stomach and undetectable in muscle. After challenged with Aeromonas hydrophila infection or iron-dextran stimulation, the hepcidin transcript levels were analyzed by RT-PCR. The results revealed that the expression of hepcidin dramatically increased at 24 h post-infection of the pathogen injection. Moreover, hepcidin mRNAs in the liver, intestine and brain were 2.4, 1.5 and 2-fold increase, respectively, compared with the control animals after 5 days in iron-dextran injected RFEs.Key words: Rice field eel, Monopterus albus, hepcidin, gene expressio
Holographic Superconductors from Einstein-Maxwell-Dilaton Gravity
We construct holographic superconductors from Einstein-Maxwell-dilaton
gravity in 3+1 dimensions with two adjustable couplings and the charge
carried by the scalar field. For the values of and we
consider, there is always a critical temperature at which a second order phase
transition occurs between a hairy black hole and the AdS RN black hole in the
canonical ensemble, which can be identified with the superconducting phase
transition of the dual field theory. We calculate the electric conductivity of
the dual superconductor and find that for the values of and where
is small the dual superconductor has similar properties to the
minimal model, while for the values of and where is
large enough, the electric conductivity of the dual superconductor exhibits
novel properties at low frequencies where it shows a "Drude Peak" in the real
part of the conductivity.Comment: 25 pages, 13 figures; v2, typos corrected; v3, refs added, to appear
in JHE
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