13,881 research outputs found
Relativistic Heavy Quark Effective Action
We study the fermion action needed to accurately describe the low energy
physics of systems including heavy quarks in lattice QCD even when the heavy
fermion mass is on the order of, or larger than, the inverse lattice
spacing: . We carry out an expansion through first order in (where is the heavy quark momentum) and all orders in ,
refining the analysis of the Fermilab and Tsukuba groups. We demonstrate that
the spectrum of heavy quark bound states can be determined accurately through
and for arbitrary exponent by using a lattice action
containing only three unknown coefficients: , and (a
generalization of ), which are functions of . In a companion paper,
we show how these three coefficients can be precisely determined using
non-perturbative techniques.Comment: 40 pages, 1 figur
Remarks on the Theory of Cosmological Perturbation
It is shown that the power spectrum defined in the Synchronous Gauge can not
be directly used to calculate the predictions of cosmological models on the
large-scale structure of universe, which should be calculated directly by a
suitable gauge-invariant power spectrum or the power spectrum defined in the
Newtonian Gauge.Comment: 13 pages, 1 figure, minor changes, to be published in Chinese Physics
Letter
First Lattice Study of the - Transition Form Factors
Experiments at Jefferson Laboratory, MIT-Bates, LEGS, Mainz, Bonn, GRAAL, and
Spring-8 offer new opportunities to understand in detail how nucleon resonance
() properties emerge from the nonperturbative aspects of QCD. Preliminary
data from CLAS collaboration, which cover a large range of photon virtuality
show interesting behavior with respect to dependence: in the region
, both the transverse amplitude, , and the
longitudinal amplitude, , decrease rapidly. In this work, we
attempt to use first-principles lattice QCD (for the first time) to provide a
model-independent study of the Roper-nucleon transition form factor.Comment: 4 pages, 2 figures, double colum
Expression of Green Fluorescence Protein (GFP) in Zebrafish Muscle through Injection: A Gene Therapy Model
Expression of the target gene is important for gene therapy. Presently, localized transgenesis is used for gene therapy which can be achieved by a target gene expression. Here, we have reported the plasmid mediated gene therapy to zebrafish model. For this purpose, we have chosen green fluorescent protein (GFP) as a target gene because the expression can be detected easily. GFP was inserted in a plasmid vector, pQE30 to develop the vector pQE30GFP. The plasmid pQE30GFP was constructed form plasmid, pQE30 and pEGFPC2. pQE30GFP injected directly in one group of fish into the muscle where luciferase expression was noted. In another group, after injection electroporation was performed where we have also noted luciferase expression; but, electroporation cause muscle injury to the zebrafish. In our case, the expression was very strong at the site of injection in first group in compare to electroporation group and in both the cases expression was stable more than two weeks
Cost of health care utilization among homeless frequent emergency department users
Research demonstrates that homelessness is associated with frequent use of emergency department (ED) services, yet prior studies have not adequately examined the relationship between frequent ED use and utilization of non-ED health care services among those experiencing homelessness. There has also been little effort to assess heterogeneity among homeless individuals who make frequent use of ED services. To address these gaps, the present study used Medicaid claims data from 2010 to estimate the association between the number of ED visits and non-ED health care costs for a cohort of 6,338 Boston Health Care for the Homeless Program patients, and to identify distinct subgroups of persons in this cohort who made frequent use of ED services based on their clinical and demographic characteristics. A series of gamma regression models found more frequent ED use to be associated with higher non-ED costs, even after adjusting for demographic and clinical characteristics. Latent class analysis was used to examine heterogeneity among frequent ED users, and the results identified 6 characteristically distinct subgroups among these persons. The subgroup of persons with trimorbid illness had non-ED costs that far exceeded members of all 5 other subgroups. Study findings reinforce the connection between frequent ED use and high health care costs among homeless individuals and suggest that different groups of homeless frequent ED users may benefit from interventions that vary in terms of their composition and intensity
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Photothermal Conversion Characteristics of Silver Nanoparticle Dispersions
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Nanoparticle-based direct absorption system is a recent development, which employs nanoparticles to absorb and convert solar energy directly into thermal energy within the fluid volume. This work reports for the first time the use of plasomic nanoparticles (PNPs) to improve the direct photo-thermal conversion efficiency. Rod-shaped silver nanoparticles are synthesized and used as an example to illustrate the photo-thermal conversion characteristics of PNPs and the effect of particle shape. The result reveals a significant role of particle morphology on the photo-thermal conversion efficiency (PTE). For spherical silver particles, constant specific absorption rate (SAR), ~0.14 kW/g, is observed and the PTE increases nearly linearly with the particle concentration. For rod-shaped silver nanoparticles, much higher SARs (2~5 kW/g) are obtained, and the PTE increases from 43% (pure DI water) to 61% at a low concentration of 0.0028%. It is suggested that the increased specific surface area and the absorption spectrum variation are the two main reasons for the strong heating effect of rod-shaped silver nanoparticles
1082 Free-breathing single-shot DENSE myocardial strain imaging using deformable registration
Free-breathing scans are often desirable in patients who find breath-holding difficult. We present a new approach for free-breathing myocardial strain imaging with displacement-encoding (DENSE) [1]. It acquires images with a single-shot sequence and removes respiratory motion using deformable registration
Interrogation of alternative splicing events in duplicated genes during evolution
<p>Abstract</p> <p>Background</p> <p>Gene duplication provides resources for developing novel genes and new functions while retaining the original functions. In addition, alternative splicing could increase the complexity of expression at the transcriptome and proteome level without increasing the number of gene copy in the genome. Duplication and alternative splicing are thought to work together to provide the diverse functions or expression patterns for eukaryotes. Previously, it was believed that duplication and alternative splicing were negatively correlated and probably interchangeable.</p> <p>Results</p> <p>We look into the relationship between occurrence of alternative splicing and duplication at different time after duplication events. We found duplication and alternative splicing were indeed inversely correlated if only recently duplicated genes were considered, but they became positively correlated when we took those ancient duplications into account. Specifically, for slightly or moderately duplicated genes with gene families containing 2 - 7 paralogs, genes were more likely to evolve alternative splicing and had on average a greater number of alternative splicing isoforms after long-term evolution compared to singleton genes. On the other hand, those large gene families (contain at least 8 paralogs) had a lower proportion of alternative splicing, and fewer alternative splicing isoforms on average even when ancient duplicated genes were taken into consideration. We also found these duplicated genes having alternative splicing were under tighter evolutionary constraints compared to those having no alternative splicing, and had an enrichment of genes that participate in molecular transducer activities.</p> <p>Conclusions</p> <p>We studied the association between occurrences of alternative splicing and gene duplication. Our results implicate that there are key differences in functions and evolutionary constraints among singleton genes or duplicated genes with or without alternative splicing incidences. It implies that the gene duplication and alternative splicing may have different functional significance in the evolution of speciation diversity.</p
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