453 research outputs found
Relativistic Meson Spectroscopy and In-Medium Effects
We extend our earlier model of mesons using relativistic
quasipotential (QP) wave equations to include open-flavor states and running
quark-gluon coupling effects. Global fits to meson spectra are achieved with
rms deviations from experiment of 43-50 MeV. We examine in-medium effects
through their influence on the confining interaction and predict the confining
strength at which the masses of certain mesons fall below the threshold of
their dominant decay channel.Comment: 12 Pages, 2 Postscript figures (appended at the end with
instructions, available also from [email protected]
Intermingled basins in coupled Lorenz systems
We consider a system of two identical linearly coupled Lorenz oscillators,
presenting synchro- nization of chaotic motion for a specified range of the
coupling strength. We verify the existence of global synchronization and
antisynchronization attractors with intermingled basins of attraction, such
that the basin of one attractor is riddled with holes belonging to the basin of
the other attractor and vice versa. We investigated this phenomenon by
verifying the fulfillment of the mathematical requirements for intermingled
basins, and also obtained scaling laws that characterize quantitatively the
riddling of both basins for this system
The FLUKA code for application of Monte Carlo methods to promote high precision ion beam therapy
Monte Carlo (MC) methods are increasingly being utilized to support several aspects of commissioning and clinical operation of ion beam therapy facilities. In this contribution two emerging areas of MC applications are outlined. The value of MC modeling to promote accurate treatment planning is addressed via examples of application of the FLUKA code to proton and carbon ion therapy at the Heidelberg Ion Beam Therapy Center in Heidelberg, Germany, and at the Proton Therapy Center of Massachusetts General Hospital (MGH) Boston, USA. These include generation of basic data for input into the treatment planning system (TPS) and validation of the TPS analytical pencil-beam dose computations. Moreover, we review the implementation of PET/CT (Positron-Emission-Tomography / Computed- Tomography) imaging for in-vivo verification of proton therapy at MGH. Here, MC is used to calculate irradiation-induced positron-emitter production in tissue for comparison with the +-activity measurement in order to infer indirect information on the actual dose delivery
Effective Swarm Parameters And Transport Coefficients In CO2 Laser Mixtures
A pulsed electron swarm technique has been used to obtain effective attachment and ionization cross-sections as well as electron drift velocities in mixtures of CO2 laser interest. In binary CO2:N 2 mixtures, below a reduced electric field of E/N=60*10 -17 V cm2, attachment was the principal ion production process. (N is the total gas number density.) The reduced attachment coefficients measured were small and in excellent agreement with numerical predictions. In ternary mixtures of He:CO2:N2, positive ion formation described by Townsend\u27s first ionisation coefficient played a more important role over the same range of E/N. The reduced coefficient for total ion formation was measured and found to be in good agreement with numerical calculations. Electron drift velocities in both the binary and ternary mixtures were determined using a time-of-flight technique. Overall agreement with previous experimental and numerical results was good
The Determinants Of Human Wellbeing In Professional Activities
The article discusses the issue of person's attitude towards success in his professional activities, which are the value of human labor and his wellbeing in professioanl activity. Personal attitude and substantial components of socio-psychological factors of attitude development provides the field of welfare of the employee. It focuses on the implementation of efficient technologies of formation attitude towards success in the process of training and retraining. The object of the research was the OJSC Evrazruda candidate pool members studying at the Evraz Siberia Regional Staff Training Center, as well as a group of experts (engineer, metallurgists). The techniques of V. K. Gerbachevsky, V. V. Stolin, S. R. Panteleyev, H. J. Eysenck, M. Rokeach, N. M. Peysakhov and J. Rotter were used in the research. The study showed the interconnection of a person's attitude with the dominant features of the component structure of motivational, volitional and self-consciousness factors. They are the determinants of wellbeing and quality of life in professional activity
On the Aggregation of Inertial Particles in Random Flows
We describe a criterion for particles suspended in a randomly moving fluid to
aggregate. Aggregation occurs when the expectation value of a random variable
is negative. This random variable evolves under a stochastic differential
equation. We analyse this equation in detail in the limit where the correlation
time of the velocity field of the fluid is very short, such that the stochastic
differential equation is a Langevin equation.Comment: 16 pages, 2 figure
The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?
This work seeks to understand the kinetics of O2 and SO2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620 nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO2 consumption is favoured by low levels of SO2, by a low availability of free SO2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins
study protocol for a randomised controlled trial
Background Immunosuppression with calcineurin inhibitors remains the mainstay
of treatment after kidney transplantation; however, long-term use of these
drugs may be associated with nephrotoxicity. In this regard, the current
approach is to optimise available immunosuppressive regimens to reduce the
calcineurin inhibitor dose while protecting renal function without affecting
the efficacy. The ATHENA study is designed to evaluate renal function in two
regimens: an everolimus and reduced calcineurin inhibitor-based regimen versus
a standard treatment protocol with mycophenolic acid and tacrolimus in de novo
kidney transplant recipients. Method/Design ATHENA is a 12-month, multicentre,
open-label, prospective, randomised, parallel-group study in de novo kidney
transplant recipients (aged 18 years or older) receiving renal allografts from
deceased or living donors. Eligible patients are randomised (1:1:1) prior to
transplantation to one of the following three treatment arms: everolimus
(starting dose 1.5 mg/day; C0 3–8 ng/mL) with cyclosporine or everolimus
(starting dose 3 mg/day; C0 3–8 ng/mL) with tacrolimus or mycophenolic acid
(enteric-coated mycophenolate sodium at 1.44 g/day or mycophenolate mofetil at
2 g/day) with tacrolimus; in combination with corticosteroids. All patients
receive induction therapy with basiliximab. The primary objective is to
demonstrate non-inferiority of renal function (eGFR by the Nankivell formula)
in one of the everolimus arms compared with the standard group at month 12
post transplantation. The key secondary objective is to assess the incidence
of treatment failure, defined as biopsy-proven acute rejection, graft loss, or
death, among the treatment groups. Other objectives include assessment of the
individual components of treatment failure, incidence and severity of viral
infections, incidence and duration of delayed graft function, incidence of
indication biopsies, slow graft function and wound healing complications, and
overall safety and tolerability. Exploratory objectives include evaluation of
left ventricular hypertrophy assessed by the left ventricular mass index,
evolution of human leukocyte antigen and non-human leukocyte antigen
antibodies, and a cytomegalovirus substudy. Discussion As one of the largest
European multicentre kidney transplant studies, ATHENA will determine whether
a de novo everolimus-based regimen can preserve renal function versus the
standard of care. This study further assesses a number of clinical issues
which impact long-term outcomes post transplantation; hence, its results will
have a major clinical impact
Unmixing in Random Flows
We consider particles suspended in a randomly stirred or turbulent fluid.
When effects of the inertia of the particles are significant, an initially
uniform scatter of particles can cluster together. We analyse this 'unmixing'
effect by calculating the Lyapunov exponents for dense particles suspended in
such a random three-dimensional flow, concentrating on the limit where the
viscous damping rate is small compared to the inverse correlation time of the
random flow (that is, the regime of large Stokes number). In this limit
Lyapunov exponents are obtained as a power series in a parameter which is a
dimensionless measure of the inertia. We report results for the first seven
orders. The perturbation series is divergent, but we obtain accurate results
from a Pade-Borel summation. We deduce that particles can cluster onto a
fractal set and show that its dimension is in satisfactory agreement with
previously reported in simulations of turbulent Navier-Stokes flows. We also
investigate the rate of formation of caustics in the particle flow.Comment: 39 pages, 8 figure
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