764 research outputs found
Multirate Kalman filtering approach for optimal two-dimensional signal reconstruction from noisy subband systems
The International Conference on Image Processing, Santa Barbara, California, 26-29 October 1997Conventional synthesis filters in subband systems lose their optimality when additive noise due, for example, to signal quantization, disturbs the subband components. The multichannel representation of subband signal is combined with the statistical model of input signal to derive the multirate state-space model for filter bank system with additive noises. Thus the signal reconstruction problem in subband system can be formulated as the process of optimal state estimation in the equivalent multirate state-space model. With the input signal embedded in the state vector, the multirate Kalman filtering provides the minimum-variance reconstruction of input signal. Using the powerful Kronecker product notation, the results and derivations can then be extended to the 2-D cases. Incorporated with the vector dynamical model, the 2-D multirate state-space model for 2-D Kalman filtering is developed. Computer simulation with the proposed 2-D multirate Kalman filter gives favorable results.published_or_final_versio
Cell number quantification of USPIO-labeled stem cells by MRI: An in vitro study
MRI plays an expanding role in stem cell therapies. The non-invasive nature and high spatial resolution of MR imaging make MR imaging a powerful tool to investigate biologic processes at the molecular and cellular level in vivo longitudinally. Quantitative detection of stem cells after transplantation may allow assessment of stem cell localization and migration, and monitoring of the therapeutic effectiveness of stem cell therapy. In this study, we present a technique for MR quantification of magnetically labeled mouse embryonic stem cells distributed or injected in agarose gel phantoms. Apparent transverse relaxation rate enhancements (ΔR2*) were measured by gradient echo sequences. The linear relationship between ΔR2* and the concentration of USPIO-labeled mouse embryonic stem cells was observed and used for quantifying cell density and cell number after injection or transplantation. The MRI acquisition and analysis protocol were validated by good agreement between actual cell numbers and MRI-estimated cell numbers over a wide range of cell numbers. This MR technique for cell number and cell density quantification is applicable to future in vivo studies. © 2006 IEEE.published_or_final_versio
Water Oxidation Catalysed by Iron Complex of N,N′-dimethyl-2,11-diaza[3,3](2,6)pyridinophane. Spectroscopy of Iron–oxo Intermediates and Density Functional Theory Calculations
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A new mib allele with a chromosomal deletion covering foxc1a exhibits anterior somite specification defect
mibnn2002, found from an allele screen, showed early segmentation defect and severe cell death phenotypes, which are different from previously known mib mutants. Despite distinct morphological phenotypes, the typical mib molecular phenotypes: her4 down-regulation, neurogenic phenotype and cold sensitive dlc expression pattern, still remained. The linkage analysis also indicated that mibnn2002 is a new mib allele. Failure of specification in anterior 7-10 somites is likely due to lack of foxc1a expression in mibnn2002 homozygotes. Somites and somite markers gradually appeared after 7-10 somite stage, suggesting that foxc1a is only essential for the formation of anterior 7-10 somites. Apoptosis began around 16-somite stage with p53 up-regulation. To find the possible links of mib, foxc1a and apoptosis, transcriptome analysis was employed. About 140 genes, including wnt3a, foxc1a and mib, were not detected in the homozygotes. Overexpression of foxc1a mRNA in mibnn2002 homozygotes partially rescued the anterior somite specification. In the process of characterizing mibnn2002 mutation, we integrated the scaffolds containing mib locus into chromosome 2 (or linkage group 2, LG2) based on synteny comparison and transcriptome results. Genomic PCR analysis further supported the conclusion and showed that mibnn2002 has a chromosomal deletion with the size of about 9.6 Mbp.published_or_final_versio
Trends in oral anticoagulant prescribing in individuals with type 2 diabetes mellitus: a population-based study in the UK
OBJECTIVE: To evaluate oral anticoagulant (OAC) prescribing trends in type 2 diabetes mellitus (T2DM) in the UK from 2001 to 2015. DESIGN: A cross-sectional drug utilisation study. SETTING: Electronic health records from The Health Improvement Network primary care database in the UK. PARTICIPANTS: Individuals with T2DM who received a record of OAC prescription. OUTCOME MEASURES: The prescribing trends of OAC medications in individuals with T2DM were examined from 2001 to 2015, stratified by age, gender and therapeutic classifications. RESULTS: A total of 361 635 individuals with T2DM were identified, of whom 36 570 were prescribed OAC from 2001 to 2015. The prevalence of OAC prescribing increased by 50.0%, from 1781 individuals receiving OAC prescriptions (IROACP) (4.4 (95% CI 4.2 to 4.6) per 100 persons) in 2001, to 17 070 IROACP (6.6 (95% CI 6.5 to 6.7) per 100 persons) in 2015. The prevalence of warfarin prescribing decreased by 14.0%, from 1761 individuals receiving warfarin prescriptions (IRWP) (98.9 (95% CI 98.4 to 99.4) per 100 persons) in 2001, to 14 533 IRWP (85.1 (95% CI 84.6 to 85.7) per 100 persons) in 2015. This corresponded with increased prescribing of direct oral anticoagulants (DOACs), from 18 individuals receiving DOAC prescriptions (IRDOACP) (0.1 (95% CI 0.08 to 0.23) per 100 persons) in 2010, to 3016 IRDOACP (17.6 (95% CI 17.1 to 18.2) per 100 persons) in 2015, during the same period. CONCLUSIONS: Prescribing of OACs in individuals with T2DM increased from 2001 to 2015. Since the introduction of DOACs, there has been a clear shift in prescribing towards these agents. Future studies are needed to assess the safety of coadministration of OAC medications and antidiabetic therapy with T2DM
Introduction to Configuration Path Integral Monte Carlo
In low-temperature high-density plasmas quantum effects of the electrons are
becoming increasingly important. This requires the development of new
theoretical and computational tools. Quantum Monte Carlo methods are among the
most successful approaches to first-principle simulations of many-body quantum
systems. In this chapter we present a recently developed method---the
configuration path integral Monte Carlo (CPIMC) method for moderately coupled,
highly degenerate fermions at finite temperatures. It is based on the second
quantization representation of the -particle density operator in a basis of
(anti-)symmetrized -particle states (configurations of occupation numbers)
and allows to tread arbitrary pair interactions in a continuous space.
We give a detailed description of the method and discuss the application to
electrons or, more generally, Coulomb-interacting fermions. As a test case we
consider a few quantum particles in a one-dimensional harmonic trap. Depending
on the coupling parameter (ratio of the interaction energy to kinetic energy),
the method strongly reduces the sign problem as compared to direct path
integral Monte Carlo (DPIMC) simulations in the regime of strong degeneracy
which is of particular importance for dense matter in laser plasmas or compact
stars. In order to provide a self-contained introduction, the chapter includes
a short introduction to Metropolis Monte Carlo methods and the second
quantization of quantum mechanics.Comment: chapter in book "Introduction to Complex Plasmas: Scientific
Challenges and Technological Opportunities", Michael Bonitz, K. Becker, J.
Lopez and H. Thomsen (Eds.) Springer Series "Atomic, Optical and Plasma
Physics", vol. 82, Springer 2014, pp. 153-194 ISBN: 978-3-319-05436-0 (Print)
978-3-319-05437-7 (Online
Estudo comparativo de soluções em alvenaria estrutural e betão armado
No setor da construção, a principal prioridade é a redução de custos relacionados com os processos
construtivos e a sua execução. Devido à crise económica global e ao crescimento da competitividade
do setor da construção, é necessário analisar outras opções que confiram boas práticas de construção,
cumprindo os requisitos definidos na regulamentação atual.
Este estudo aborda a temática de algumas das soluções construtivas normalmente utilizadas, focando aspetos
de normalização, custos, vantagens e desvantagens. É também apresentada uma avaliação comparativa
entre dois sistemas construtivos, alvenaria estrutural vs. betão armado, de uma moradia construída
ao abrigo de um projeto de investigação. Nessa avaliação é feita a apresentação do processo de conceção
modular e conceção estrutural para ambas as soluções em fase de projeto. Este estudo também apresenta
uma comparação de custos entre dois sistemas construtivos, nomeadamente a construção em alvenaria
estrutura vs. construção em betão armado.
Com o estudo realizado constatou-se que no projeto é notória a complexidade da alvenaria estrutural em
detrimento do betão armado. A alvenaria estrutural também apresenta limitações a eventuais alterações
executadas durante a vida útil do edifício. Relativamente à comparação de custos efetuada, os resultados
mostram que a construção em alvenaria estrutural é um processo tecnológico apropriado e a redução de
custos é significativa
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Low-density superhard materials: Computational study of Li-inserted B-substituted closo-carboranes LiBC<inf>11</inf> and Li<inf>2</inf>B<inf>2</inf>C<inf>10</inf>
Insertion of Li atoms into a B-substituted carbon cage produces two superhard compounds with relatively low density: LiBC11 and Li2B2C10.X. F. and Q. L. acknowledge the funding supports from the National Natural Science Foundation of China under Grant No. 11474125, 11274136 and 11534003. J. T. and H. L. acknowledge the National Science Foundation of China (11474126) and support from the University of Saskatchewan research computing group and the use of the HPC resources (Plato machine).This is the author accepted manuscript. The final version is available from the Royal Society Of Chemistry via http://dx.doi.org/10.1039/C6RA10177
International Collaborative Partnership for the Study of Atrial Fibrillation (INTERAF): Rationale, Design, and Initial Descriptives.
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Crystal Structures of CaB3N3 at High Pressures
Using global structure searches, we have explored the structural stability of CaBN, a compound analogous to CaC, under pressure. There are two high-pressure phases with space groups and that were found to be stable between 29 and 42 GPa, and above 42 GPa, respectively. The two phases show different structural frameworks, analogous to graphitic CaC. Phonon calculations confirm that both structures are also dynamically stable at high pressures. The electronic structure calculations show that the phase is a semiconductor with a band gap of 2.21 eV and that the phase is a semimetal. These findings help advance our understanding of the Ca-B-N ternary system.This research was supported by the Natural Science Foundation of China under No. 11504007, 11404035, and the Scientific and Technological Research Project of the ‘‘13th Five-Year Plan’’ of Jilin Provincial Education Department under Grant No. 201648 and 201649. Work at Carnegie was supported by EFree, an Energy Frontier Research Center funded by the DOE, Office of Science, Basic Energy Sciences under Award No. DE-SC-0001057. The infrastructure and facilities used at Carnegie were supported by NNSA Grant No. DE-NA-0002006, CDAC. JST thanks the National Natural Science Foundation of China under Grant No. 11474126
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