50,105 research outputs found
Quantifying the roles of cell motility and cell proliferation in a circular barrier assay
No full textMoving fronts of cells are essential features of embryonic development, wound repair and cancer metastasis. This paper describes a set of experiments to investigate the roles of random motility and proliferation in driving the spread of an initially confined cell population. The experiments include an analysis of cell spreading when proliferation was inhibited. Our data have been analysed using two mathematical models: a lattice-based discrete model and a related continuum partial differential equation model. We obtain independent estimates of the random motility parameter, D, and the intrinsic proliferation rate, λ, and we confirm that these estimates lead to accurate modelling predictions of the position of the leading edge of the moving front as well as the evolution of the cell density profiles. Previous work suggests that systems with a high λ/D ratio will be characterized by steep fronts, whereas systems with a low λ/D ratio will lead to shallow diffuse fronts and this is confirmed in the present study. Our results provide evidence that continuum models, based on the Fisher–Kolmogorov equation, are a reliable platform upon which we can interpret and predict such experimental observations.Matthew J. Simpson, Katrina K. Treloar, Benjamin J. Binder, Parvathi Haridas, Kerry J. Manton, David I. Leavesley, D. L. Sean McElwain and Ruth E. Bake
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
Get PDFFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Non-alcoholic steatohepatitis in children and adolescents
No full textCopyright © 2000 Australasian Medical PublishingWe describe 17 children with non-alcoholic steatohepatitis. All had elevated levels of serum liver enzymes and 16 were morbidly obese. Liver biopsy showed variable steatosis and fibrosis in nine patients. At follow-up, 12 of 14 patients had persistent morbid obesity and 11 had elevated liver enzyme levels.Nicholas D Manton, Jill Lipsett, David J Moore, Geoffrey P Davidson, Anthony J Bourne and Richard T L Coupe
Detection and diagnosis of carious lesions:Factual clinical approaches
Get PDFMinimal intervention dentistry is the accepted contemporary approach for caries management -both for the disease and the lesion. The development of adjunctive technologies to assist early lesion detection and quantifcation has led to the marketing of various devices over the past two decades. A thorough understanding of the clinical relevance of these devices is important to make precise interpretation of the information provided by the individual technologies. In this chapter, we will describe and discuss the most common commercially available carious lesion detection technologies in order to give dental practitioners clear information about the technology details and reliable and reproducible use of each device, its advantages and limitations, using a clinical approach.</p
Measurement of the B0–B0 oscillation frequency Δmd with the decays B0→D−π+ and B0→ J/ψK∗0
Get PDFThe B
0
–B
0
oscillation frequency Δmd is measured by the LHCb experiment using a dataset corresponding
to an integrated luminosity of 1.0 fb−1
of proton–proton collisions at √
s = 7 TeV, and is found to be
Δmd
=0.5156±0.0051 (stat.)±0.0033 (syst.) ps−1
. The measurement is based on results from analyses
of the decays B
0
→ D
−π
+ (D
−
→ K
+π
−π
−) and B
0
→ J/ψK
∗0
(J/ψ →μ
+μ
−,K
∗0
→ K
+π
−) and
their charge conjugated modes
Aspects of D-Branes as BPS monopoles
Get PDFWe investigate some of the properties of D-brane configurations which behave as BPS monopoles. The two D-brane configurations we will study are the enhançon and D-strings attached to D3-branes.We will start by investigating D3-branes wrapped on a K3 manifold, which are known as enhançons. They look like regions of enhanced gauge symmetry in the directions transverse to the branes, and therefore behave as BPS monopoles. We calculate the metric on moduli space for n enhançons, following the methods used by Ferrell and Eardley for black holes. We expect the result to be the higher-dimensional generalisation of the Taub-NUT metric, which is the metric on moduli space for n BPS monopoles. Next we will study D-strings attached to D3-branes; the ends of the D-strings behave as BPS monopoles of the world volume gauge theory living on the D3-branes. In fact the D-string/D3-brane system is a physical realisation of the ADHMN construction for BPS monopoles. We aim to test this correspondence by calculating the energy radiated during D-string scattering, working with the non-Abelian Born-Infeld action for D-strings. We will then compare our result to the equivalent monopole calculation of Manton and Samols
Search for the rare decays J/y -> D-s(-) rho(+) and J/psi -> <(D)over bar(0)<(K)over bar*(0)
No full textA search for the rare decays of J/psi -> D-S(-) rho(+) + c.c. and J/psi -> D-S(-)rho(+) + c.c.) <1.3 x 10(-5) and beta(J/psi -
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Search for the weak decays J/psi -> D-s(()*()-) e(+)nu(e) + c.c.
No full textUsing a sample of 2.25 x 10(8) J/psi events collected with the BESIII detector at the BEPCII collider, we search for the J/psi semileptonic weak decay J/psi -> D-s(-) e(+)nu(e) +c.c. with a much higher sensitivity than previous searches. We also perform the first search for J/psi -> D-s(*-) e(+) nu(e) + c.c. No significant excess of a signal above background is observed in either channel. At the 90% confidence level, the upper limits are determined to be B(J/psi -> D-s(-) e(+) nu(e) + c.c.) D-s*(-) e(+) nu(e) + c.c.) <1.8 x 10(-6), respectively. Both are consistent with Standard Model predictions
The R&D Tax Incentives
No full textThis article sets out some background information and reflections of the author on the R&D tax incentive schemes included in the Common Corporate Tax Base (CCTB) Proposal. In particular the author analyzes the stimulus to private R&D through ad hoc tax incentives included in the CCTB Proposal and dives into the actual provisions included in the Proposal highlighting the most relevant issues connected with their design and interpretation. Moreover, the author explores the interaction between the CCTB Proposal and the granting by Member States of domestic R&D tax incentives
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