3D elastic inversion of vertical seismic profiles in horizontally stratified media; Inversion elastique 3D de profils sismiques verticaux en milieux stratifies horizontalement

Energy Technology Data Exchange (ETDEWEB)

Petit, J.L.

1997-07-21

This thesis is devoted to the inversion of VSP (vertical seismic profile) seismic data in order to determine the elastic properties of horizontally stratified media. The VSP records are computed using the full wave elastic modelling in isotropic and transversely isotropic media using Hankel transform, a finite difference scheme and an inverse Hankel transform algorithm, and the propagation equations are determined and numerically solved; the importance of considering a 3D wave propagation model instead of a 1 D one is emphasized. The theoretical VSP inverse problem is then considered, with the seismic waveform inversion set as a least-squares problem, consisting in recovering the distribution of physical parameters which minimize the misfit between calculated and observed VSP. The corresponding problem requires the knowledge of the source function

Hydrodynamic and hydromagnetic stability

CERN Document Server

Chandrasekhar, S

1981-01-01

Dr. Chandrasekhar's book received high praise when it first appeared in 1961 as part of Oxford University Press' International Series of Monographs on Physics. Since then it has been reprinted numerous times in its expensive hardcover format. This first lower-priced, sturdy paperback edition will be welcomed by graduate physics students and scientists familiar with Dr. Chandrasekhar's work, particularly in light of the resurgence of interest in the Rayleigh-Bénard problem. This book presents a most lucid introduction to the Rayleigh-Bénard problem: it has also been applauded for its thorough, clear coverage of the theory of instabilities causing convection. Dr. Chandrasekhar considers most of the typical problems in hydromagnetic stability, with the exception of viscous shear flow; a specialized domain deserving a book unto itself. Contents include: Rotation; Stability of More General Flows; Bénard Problem; Gravitational Equilibrium and Instability; Stability of a Magnetic Field; Thermal Instability of a L...

Thermo-diffusion effect on free convection heat and mass transfer in a thermally linearly stratified non-darcy porous media

KAUST Repository

Murthy, P.V.S.N.

2011-12-26

Thermo-diffusion effect on free convection heat and mass transfer from a vertical surface embedded in a liquid saturated thermally stratified non - Darcy porous medium has been analyzed using a local non-similar procedure. The wall temperature and concentration are constant and the medium is linearly stratified in the vertical direction with respect to the thermal conditions. The fluid flow, temperature and concentration fields are affected by the complex interactions among the diffusion ratio Le, buoyancy ratio N, thermo-diffusion parameter Sr and stratification parameter ?. Non-linear interactions of all these parameters on the convective transport has been analyzed and variation of heat and mass transfer coefficients with thermo-diffusion parameter in the thermally stratified non-Darcy porous media is presented through computer generated plots.

Thermo-diffusion effect on free convection heat and mass transfer in a thermally linearly stratified non-darcy porous media

KAUST Repository

Murthy, P.V.S.N.; El-Amin, Mohamed

2011-01-01

Thermo-diffusion effect on free convection heat and mass transfer from a vertical surface embedded in a liquid saturated thermally stratified non - Darcy porous medium has been analyzed using a local non-similar procedure. The wall temperature and concentration are constant and the medium is linearly stratified in the vertical direction with respect to the thermal conditions. The fluid flow, temperature and concentration fields are affected by the complex interactions among the diffusion ratio Le, buoyancy ratio N, thermo-diffusion parameter Sr and stratification parameter ?. Non-linear interactions of all these parameters on the convective transport has been analyzed and variation of heat and mass transfer coefficients with thermo-diffusion parameter in the thermally stratified non-Darcy porous media is presented through computer generated plots.

Hydromagnetic modes in an inhomogeneous collisionless plasma of finite pressure

International Nuclear Information System (INIS)

Klimushkin, D.Yu.

2006-01-01

One studied three-dimensional structure and rate of growth of hydromagnetic waves. The mode is shown to be the Alfven modified inhomogeneity, finite pressure and plasma anisotropy. The mode structure transverse the magnetic shells may be of two types. Under some specific conditions one may observe image-drift waves in the magnetosphere. The described modes may be responsible for some types of geomagnetic field oscillations [ru

Stochastic line motion and stochastic flux conservation for nonideal hydromagnetic models

International Nuclear Information System (INIS)

Eyink, Gregory L.

2009-01-01

We prove that smooth solutions of nonideal (viscous and resistive) incompressible magnetohydrodynamic (MHD) equations satisfy a stochastic law of flux conservation. This property implies that the magnetic flux through a surface is equal to the average of the magnetic fluxes through an ensemble of surfaces advected backward in time by the plasma velocity perturbed with a random white noise. Our result is an analog of the well-known Alfven theorem of ideal MHD and is valid for any value of the magnetic Prandtl number. A second stochastic conservation law is shown to hold at unit Prandtl number, a random version of the generalized Kelvin theorem derived by Bekenstein and Oron for ideal MHD. These stochastic conservation laws are not only shown to be consequences of the nonideal MHD equations but are proved in fact to be equivalent to those equations. We derive similar results for two more refined hydromagnetic models, Hall MHD and the two-fluid plasma model, still assuming incompressible velocities and isotropic transport coefficients. Finally, we use these results to discuss briefly the infinite-Reynolds-number limit of hydromagnetic turbulence and to support the conjecture that flux conservation remains stochastic in that limit.

Hydromagnetic flow and radiative heat transfer of nanofluid past a vertical plate

Directory of Open Access Journals (Sweden)

B. Ganga

2017-11-01

Full Text Available Hydromagnetic flow of an incompressible viscous nanofluid past a vertical plate in the presence of thermal radiation is investigated both analytically and numerically. The radiative heat flux is described by the Rosseland diffusion approximation in the energy equation. The governing non-linear partial differential equations are converted into a set of ordinary differential equations by suitable similarity transformations. The resulting ordinary differential equations are successfully solved analytically with the help of homotopy analysis method and numerically by the fourth order Runge–Kutta method with shooting technique. The effects of various physical parameters are analyzed and discussed in graphical and tabular forms. The effects of some physical parameters such as Lewis number, Prandtl number, buoyancy ratio, thermophoresis, Brownian motion, radiation parameter and magnetic parameter are analyzed on the velocity, temperature and solid volume fraction profiles as well as on the reduced Nusselt number and the local Sherwood number. An excellent agreement is observed between present analytical and numerical results. Keywords: Nanofluid, Hydromagnetic, Homotopy analysis method, Vertical plate and thermal radiation

Thermal radiation effects on hydromagnetic flow

International Nuclear Information System (INIS)

Abdelkhalek, M.M.

2005-01-01

Numerical results are presented for the effects of thermal radiation, buoyancy and heat generation or absorption on hydromagnetic flow over an accelerating permeable surface. These results are obtained by solving the coupled nonlinear partial differential equations describing the conservation of mass, momentum and energy by a perturbation technique. This qualitatively agrees with the expectations, since the magnetic field exerts a retarding force on the free convection flow. A parametric study is performed to illustrate the influence of the radiation parameter, magnetic parameter, Prandtl number, Grashof number and Schmidt number on the profiles of the velocity components and temperature. The effects of the different parameters on the velocity and temperature profiles as well as the skin friction and wall heat transfer are presented graphically. Favorable comparisons with previously published work confirm the correctness of numerical results

Hydromagnetic turbulence in the direct interaction approximation

International Nuclear Information System (INIS)

Nagarajan, S.

1975-01-01

The dissertation is concerned with the nature of turbulence in a medium with large electrical conductivity. Three distinct though inter-related questions are asked. Firstly, the evolution of a weak, random initial magnetic field in a highly conducting, isotropically turbulent fluid is discussed. This was first discussed in the paper 'Growth of Turbulent Magnetic Fields' by Kraichnan and Nagargian. The Physics of Fluids, volume 10, number 4, 1967. Secondly, the direct interaction approximation for hydromagnetic turbulence maintained by stationary, isotropic, random stirring forces is formulated in the wave-number-frequency domain. Thirdly, the dynamical evolution of a weak, random, magnetic excitation in a turbulent electrically conducting fluid is examined under varying kinematic conditions. (G.T.H.)

Low Energy Particle Oscillations and Correlations with Hydromagnetic Waves in the Jovian Magnetosphere: Ulysses Measurements

Science.gov (United States)

Krupp, N.; Tsurutani, B. T.; Lanzerotti, L. J.; Maclennan, C. G.

1996-01-01

We report on measurements of energetic particle modulations observed by the HI-SCALE instrument aboard the Ulysses Spacecraft that were associated with the only hydromagnetic wave event measured inside the Jovian magnetosphere by the Ulysses magnetometer investigation.

Layer contributions to the nonlinear acoustic radiation from stratified media.

Science.gov (United States)

Vander Meulen, François; Haumesser, Lionel

2016-12-01

This study presents the thorough investigation of the second harmonic generation scenario in a three fluid layer system. An emphasis is on the evaluation of the nonlinear parameter B/A in each layer from remote measurements. A theoretical approach of the propagation of a finite amplitude acoustic wave in a multilayered medium is developed. In the frame of the KZK equation, the weak nonlinearity of the media, attenuation and diffraction effects are computed for the fundamental and second harmonic waves propagating back and forth in each of the layers of the system. The model uses a gaussian expansion to describe the beam propagation in order to quantitatively evaluate the contribution of each part of the system (layers and interfaces) to its nonlinearity. The model is validated through measurements on a water/aluminum/water system. Transmission as well as reflection configurations are studied. Good agreement is found between the theoretical results and the experimental data. The analysis of the second harmonic field sources measured by the transducers from outside the stratified medium highlights the factors that favor the cumulative effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Possibilities of heating a TFR plasma by absorption of the fast hydromagnetic wave

International Nuclear Information System (INIS)

Adam, J.

The prospects of TFR heating by fast hydromagnetic waves are considered by an examination of the following topics: (1) characteristics of the dispersion relation, (2) the charge impedance of an antenna capable of exciting these modes, and (3) the heating effects which would be caused by dissipation of these waves around ω = ω/sub ci/ and ω = 2ω/sub ci/

Destabilization of hydromagnetic drift-Alfven waves in a finite pressure collisional plasma

International Nuclear Information System (INIS)

Tang, J.T.

1974-01-01

In a finite beta (β = 8πn 0 kT 0 /B 0 2 ) plasma, where the plasma pressure n 0 kT 0 is an appreciable fraction of the confining magnetic field energy-density B 0 2 /8π, density-gradient driven drift waves couple with Alfven waves when the phase velocities of the two waves become comparable. The resulting hydromagnetic drift-Alfven waves separate into two branches--a drift mode and an Alfven mode, with both modes exhibiting magnetic field and localized density fluctuations near the coupling point. The dispersion relation of the collisional drift-Alfven wave is derived by using a slab-geometry, two-fluid model which includes finite beta, electron-ion collisions, ion-ion collisions, finite ion larmar radius, temperature fluctuations, and an axial electron current. A hydromagnetic drift mode is found to be unstable in a moderately dense plasma. A localized ''Alfven'' mode is destabilized only with the passage of an axial current along the plasma column. In order to check the theoretical predictions an experiment is performed in a finite-beta plasma of density n 0 = 10 13 -10 15 cm -3 and temperature T/sub e/ approximately T/sub i/ = 1-7 eV. (U.S.)

Electromagnetic fields in stratified media

CERN Document Server

Li, Kai

2009-01-01

Dealing with an important branch of electromagnetic theory with many useful applications in subsurface communication, radar, and geophysical prospecting and diagnostics, this book introduces electromagnetic theory and wave propagation in complex media.

Shear flow stabilization of the hydromagnetic Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Roderick, N.F.; Shumlak, U.; Douglas, M.; Peterkin, R.E. Jr.; Ruden, E.

1997-01-01

Numerical simulations have indicated that shear flow may help stabilize the hydromagnetic Rayleigh-Taylor instability in imploding plasma z-pinches. A simple extension to a model presented in Chandrasekhar has been developed to study the linear stability of incompressible plasma subjected to both a shear flow and acceleration. The model has been used to investigate the stability plasma implosion schemes using externally imposed velocity shear which develops from the plasma flow itself. Specific parameters were chosen to represent plasma implosions driven by the Saturn and PBFA-Z, pulsed power generators at Sandia National Laboratories. Results indicate a high shear is necessary to stabilize the z-pinch implosions studied

Computation of potentials from current electrodes in cylindrically stratified media: A stable, rescaled semi-analytical formulation

Science.gov (United States)

Moon, Haksu; Teixeira, Fernando L.; Donderici, Burkay

2015-01-01

We present an efficient and robust semi-analytical formulation to compute the electric potential due to arbitrary-located point electrodes in three-dimensional cylindrically stratified media, where the radial thickness and the medium resistivity of each cylindrical layer can vary by many orders of magnitude. A basic roadblock for robust potential computations in such scenarios is the poor scaling of modified-Bessel functions used for computation of the semi-analytical solution, for extreme arguments and/or orders. To accommodate this, we construct a set of rescaled versions of modified-Bessel functions, which avoids underflows and overflows in finite precision arithmetic, and minimizes round-off errors. In addition, several extrapolation methods are applied and compared to expedite the numerical evaluation of the (otherwise slowly convergent) associated Sommerfeld-type integrals. The proposed algorithm is verified in a number of scenarios relevant to geophysical exploration, but the general formulation presented is also applicable to other problems governed by Poisson equation such as Newtonian gravity, heat flow, and potential flow in fluid mechanics, involving cylindrically stratified environments.

Coupled hydromagnetic wave excitation and ion acceleration upstream of the earth's bow shock

International Nuclear Information System (INIS)

Lee, M.A.

1982-01-01

A self-consistent theory is presented for the excitation of hydromagnetic waves and the acceleration of diffuse ions upstream of the earth's bow shock in the quasi-equilibrium that results when the solar wind velocity and the interplanetary magnetic field are nearly parallel. For the waves the quasi-equilibrium results from a balance between excitation by the ions, which stream relative to the solar wind plasma, and convective loss to the magnetosheath. For the diffuse ions the quasi-equilibrium results from a balance between injection at the shock front, confinement to the foreshock by pitch angle scattering on the waves, acceleration by compression at the shock front, loss to the magnetosheath, loss due to escape upstream of the foreshock, and loss via diffusion perpendicular to the average magnetic field onto field lines that do not connect to the shock front. Diffusion equations describing the ion transport and wave kinetic equations describing the hydromagnetic wave transport are solved self-consistently to yield analytical expressions for the differential wave intensity spectrum as a function of frequency and distance from the bow shock z and for the ion omnidirectional distribution functions and anisotropies as functions of energy and z, In quantitative agreement with observations, the theory predicts (1) exponential spectra at the bow shock in energy per charge, (2) a decrease in intensity and hardening of the ion spectra with increasing z, (3) a 30-keV proton anisotropy parallel to z increasing from -0.28 at the bow shock to +0.51 as z→infinity (4) a linearly polarized wave intensity spectrum with a minimum at approx.6 x 10 -3 Hz and a maximum at approx.2--3 x 10 -2 Hz, (5) a decrease in the wave intensity spectrum with increasing z, (6) a total energy density in protons with energies >15 keV about eight times that in the hydromagnetic waves

On field line resonances of hydromagnetic Alfven waves in dipole magnetic field

International Nuclear Information System (INIS)

Chen, Liu; Cowley, S.C.

1989-07-01

Using the dipole magnetic field model, we have developed the theory of field line resonances of hydromagnetic Alfven waves in general magnetic field geometries. In this model, the Alfven speed thus varies both perpendicular and parallel to the magnetic field. Specifically, it is found that field line resonances do persist in the dipole model. The corresponding singular solutions near the resonant field lines as well as the natural definition of standing shear Alfven eigenfunctions have also been systematically derived. 11 refs

Indirect boundary element method on recursive matrix operation to compute waves in irregularly stratified media with infinitely extended interfaces. Perturbation by a point source; Kansetsu kyokai yosoho ni yoru fukisoku seiso kozochu no hadoba no keisanho. Tenshingen ni taisuru reference solution no riyo

Energy Technology Data Exchange (ETDEWEB)

Yokoi, T [Akita University, Akita (Japan). Mining College

1996-05-01

As a method of computation of wave fields in irregularly stratified media by use of the indirect boundary element method, an induction formula was proposed in a previous report, utilizing the reference solution representing the wave field in corresponding horizontally stratified media. This algorithm applies to other types of vibration source. In computation of a wave field with the focus in presence on the ground or in the ground, the algorithm is incorporated into the computation as a vector including the reference solution as a variable. There exists no need to modify the algorithm. Once the reference solution is obtained, the wave field in the irregularly stratified media is automatically constructed by the proposed algorithm. The wave field to be the reference solution to a point source in the horizontally stratified media, is determined when the solution is obtained of the frequency/wavenumber domain by use of the reflection/transmission matrix of Kennet (1983) and converted into the solution of the spatial domain by use of the discrete wavenumber representation of Bouchon and Aki (1977). 8 refs., 2 figs.

Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders

International Nuclear Information System (INIS)

Rana, M.A.; Siddiqui, A.M.; Qamar, Rashid

2009-01-01

The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties

Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders

Energy Technology Data Exchange (ETDEWEB)

Rana, M.A. [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)], E-mail: mafzalrana@yahoo.com; Siddiqui, A.M. [Department of Mathematics, Pennsylvania State University, York Campus, York, PA 17403 (United States); Qamar, Rashid [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)

2009-01-15

The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties.

Nonlinear radiative peristaltic flow of hydromagnetic fluid through porous medium

Science.gov (United States)

Hussain, Q.; Latif, T.; Alvi, N.; Asghar, S.

2018-06-01

The radiative heat and mass transfer in wall induced flow of hydromagnetic fluid through porous medium in an asymmetric channel is analyzed. The fluid viscosity is considered temperature dependent. In the theory of peristalsis, the radiation effects are either ignored or taken as linear approximation of radiative heat flux. Such approximation is only possible when there is sufficiently small temperature differences in the flow field; however, nonlinear radiation effects are valid for large temperature differences as well (the new feature added in the present study). Mathematical modeling of the problems include the complicated system of highly nonlinear differential equations. Semi-analytical solutions are established in the wave reference frame. Results are displayed graphically and discussed in detail for the variation of various physical parameters with the special attention to viscosity, radiation, and temperature ratio parameters.

Hydromagnetic instabilities and magnetic field amplification in core collapse supernovae

Energy Technology Data Exchange (ETDEWEB)

Cerda-Duran, P; Obergaulinger, M; Mueller, E [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-st. 1, 85748 Garching (Germany); Aloy, M A; Font, J A, E-mail: cerda@mpa-garching.mpg.de [Departamento de Astronomia y Astrofisica, Universidad de Valencia, 46100 Burjassot, Valencia (Spain)

2011-09-22

Some of the most violent events in the universe, the gamma ray burst, could be related to the gravitational collapse of massive stellar cores. The recent association of long GRBs to some class of type Ic supernova seems to support this view. In such scenario fast rotation, strong magnetic fields and general relativistic effects are key ingredients. It is thus important to understand the mechanism that amplifies the magnetic field under that conditions. I present global simulations of the magneto-rotational collapse of stellar cores in general relativity and semi-global simulations of hydromagnetic instabilities under core collapse conditions. I discuss effect of the magneto-rotational instability and the magnetic field amplification during the collapse, the uncertainties in this process and the dynamical effects in the supernova explosion.

Model for the saturation of the hydromagnetic Rayleigh--Taylor instability

International Nuclear Information System (INIS)

Roderick, N.F.; Hussey, T.W.

1984-01-01

The saturation of the hydromagnetic Rayleigh--Taylor instability is caused by the reduction of driving current in the bubble region between the spikes formed as the instability develops. For short wavelengths linear magnetic field diffusion provides the necessary smoothing of the magnetic field to reduce the driving force. For wavelengths longer than the magnetic field diffusion length, the current is shorted through material which expands into the bubble region. This initially low density accumulates in the bubble and eventually provides a source of sufficiently high conductivity plasma which reduces the magnetic field penetration to the front of the bubble. Simple analytic models have been developed to verify and and quantify these predictions. These models have been compared with two-dimensional magnetohydrodynamic calculations for imploding plasma shells and give good agreement with these more detailed simulations

On the stability of certain collisional configurations of hydromagnetic flows

Energy Technology Data Exchange (ETDEWEB)

Nunez, Manuel, E-mail: mnjmhd@am.uva.e [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)

2010-09-06

We study the flow of a hydromagnetic fluid toward an obstacle in two different cases: when this is a rigid wall or when two plasma masses collide with each other. The magnetic field far from the obstacle is assumed to be aligned with the flow. The diffusivity is taken as low, and a boundary layer approach for the stationary MHD system is considered. The relevant equations turn out to be a generalization of the Falkner-Skan ones, and while analytical solutions are impossible to obtain, a qualitative analysis shows that whenever the size of the Alfven speed far from the interface exceeds the size of the fluid velocity, the system has no nontrivial solutions. The interpretation of this is that in this case disturbances occurring in the boundary layer travel upstream and disturb the boundary conditions at the outer layers.

Classification of hydromagnetic emissions based on frequency--time spectra

International Nuclear Information System (INIS)

Fukunishi, H.; Toya, T.; Koike, K.; Kuwashima, M.; Kawamura, M.

1981-01-01

By using 3035 hydromagnetic emission events observed in the frequency range of 0.1--2.0 Hz at Syowa (Lapprox.6), HM emissions have been classified into eight subtypes based on their spectral structures, i.e., HM whistler, periodic HM emission, HM chorus, HM emission burst, IPDP, morning IPDP, Pc 1--2 band, and irregular HM emission. It is seen that each subtype has a preferential magnetic local time interval and also a frequency range for its occurrence. Morning IPDP events and irregular HM emissions occur in the magnetic morning hours, while dispersive periodic HM emissions and HM emission bursts occur around magnetic local noon, then HM chorus emissions occur in the afternoon hours and IPDP events occur in the evening hours. Furthermore, it is noticed that the mid-frequencies of these emissions vary from high frequencies in the morning hours to low frequencies in the afternoon hours. On the basis of these results, the generation mechanisms of each subtype are discussed

Hydromagnetic flow of third grade nanofluid with viscous dissipation and flux conditions

Energy Technology Data Exchange (ETDEWEB)

Hussain, T. [Faculty of Computing, Mohammad Ali Jinnah University, Islamabad 44000 (Pakistan); Shehzad, S. A., E-mail: ali-qau70@yahoo.com [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alsaedi, A. [Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2015-08-15

This article investigates the magnetohydrodynamic flow of third grade nanofluid with thermophoresis and Brownian motion effects. Energy equation is considered in the presence of thermal radiation and viscous dissipation. Rosseland’s approximation is employed for thermal radiation. The heat and concentration flux conditions are taken into account. The governing nonlinear mathematical expressions of velocity, temperature and concentration are converted into dimensionless expressions via transformations. Series solutions of the dimensionless velocity, temperature and concentration are developed. Convergence of the constructed solutions is checked out both graphically and numerically. Effects of interesting physical parameters on the temperature and concentration are plotted and discussed in detail. Numerical values of skin-friction coefficient are computed for the hydrodynamic and hydromagnetic flow cases.

Effect of wall conductances on hydromagnetic flow and heat transfer in a rotating channel

International Nuclear Information System (INIS)

Mazumder, B.S.

1977-01-01

Wall conductance effects on the hydromagnetic flow and heat transfer between two parallel plates in a rotating frame of reference has been studied when the liquid is permeated by a transverse magnetic field. An exact solution of the governing equation has been obtained. It is found that the velocity current density and the temperature depend only on the sum of the wall conductances phi 1 + phi 2 = phi but magnetic field depends on the individual values of phi 1 and phi 2 where phi 1 and phi 2 are respectively the wall conductance ratios of the upper and lower walls. (Auth.)

Nonlinear radiative peristaltic flow of hydromagnetic fluid through porous medium

Directory of Open Access Journals (Sweden)

Q. Hussain

2018-06-01

Full Text Available The radiative heat and mass transfer in wall induced flow of hydromagnetic fluid through porous medium in an asymmetric channel is analyzed. The fluid viscosity is considered temperature dependent. In the theory of peristalsis, the radiation effects are either ignored or taken as linear approximation of radiative heat flux. Such approximation is only possible when there is sufficiently small temperature differences in the flow field; however, nonlinear radiation effects are valid for large temperature differences as well (the new feature added in the present study. Mathematical modeling of the problems include the complicated system of highly nonlinear differential equations. Semi-analytical solutions are established in the wave reference frame. Results are displayed graphically and discussed in detail for the variation of various physical parameters with the special attention to viscosity, radiation, and temperature ratio parameters. Keywords: Nonlinear thermal radiation, Variable viscosity, Porous medium, Soret and Dufour effects, Peristalsis

Numerical treatment of the unsteady hydromagnetic thermal boundary layer problem

International Nuclear Information System (INIS)

Drymonitou, M.A.; Geroyannis, V.S.; Goudas, C.L.

1980-01-01

This paper presents a suitable numerical method for the treatment of the unsteady hydromagnetic thermal boundary layer problem for flows past an infinite porous flat plate, the motion of which is governed by a general time-dependent law, under the influence of a transverse externally set magnetic field. The normal velocity of suction/injection at the plate is also assumed to be time-dependent. The results obtained on the basis of numerical approximations seem to compare favourably with earlier results (Pande et al., 1976; Tokis, 1978). Analytical approximations are given for the cases of a plate (i) generally accelerated and (ii) harmonically oscillating. The direct numerical treatment is obviously advantageous since it allows handling of cases where the known methods for analytical approximations are not applicable. This problem is closely related to the motions and heat transfer occurring locally on the surfaces of stars. (orig.)

Studies of hydromagnetic waves and oscillations in plasmas

International Nuclear Information System (INIS)

Sawley, M.L.

1980-10-01

Small amplitude magnetoacoustic oscillations in a partially ionized, non-uniform, current carrying plasma column of finite beta are considered. The linearized magnetohydrodynamic equations are used to develop a theory describing both free and forced magnetoacoustic oscillations. The results of numerical calculations are given for the specific case of diffuse pinch equilibrium configurations. In an experimental study the amplitude of the oscillating axial magnetic flux is determined for several frequencies in the vicinity of the first magnetoacoustic resonance. Accurate determination of the plasma density profile is shown to be possible. Finite-amplitude effects on the propagation of axisymmetric hydromagnetic waves are examined. A nonlinear theory is developed which describes the second-order perturbation that accompanies the primary wave. The influence of Hall currents and the presence of neutral atoms on the second-order fields is treated. In an investigation on the propagation of torsional waves the observed second-order fields are shown to exhibit good quantitative agreement with theoretical calculations for moderate primary wave amplitudes. The re-ionization of the plasma by a torsional wave is investigated. A theoretical description is given of the nonlinear excitation of magnetoacoustic oscillations by means of an oscillating axial current

The Fokker-Planck equation for ray dispersion in gyrotropic stratified media

NARCIS (Netherlands)

Golynski, S.M.

1984-01-01

The Hamilton equations of geometrical optics determine the rays of the relevant wave field in the short wavelength. We give a systematic derivation of the Fokker-Planck equation for the joint probability density of the position and unit direction vector of rays propagating in a gyrotropic stratified

Universal shift of the Brewster angle and disorder-enhanced delocalization of p waves in stratified random media.

Science.gov (United States)

Lee, Kwang Jin; Kim, Kihong

2011-10-10

We study theoretically the propagation and the Anderson localization of p-polarized electromagnetic waves incident obliquely on randomly stratified dielectric media with weak uncorrelated Gaussian disorder. Using the invariant imbedding method, we calculate the localization length and the disorder-averaged transmittance in a numerically precise manner. We find that the localization length takes an extremely large maximum value at some critical incident angle, which we call the generalized Brewster angle. The disorder-averaged transmittance also takes a maximum very close to one at the same incident angle. Even in the presence of an arbitrarily weak disorder, the generalized Brewster angle is found to be substantially different from the ordinary Brewster angle in uniform media. It is a rapidly increasing function of the average dielectric permittivity and approaches 90° when the average relative dielectric permittivity is slightly larger than two. We make a remarkable observation that the dependence of the generalized Brewster angle on the average dielectric permittivity is universal in the sense that it is independent of the strength of disorder. We also find, surprisingly, that when the average relative dielectric permittivity is less than one and the incident angle is larger than the generalized Brewster angle, both the localization length and the disorder-averaged transmittance increase substantially as the strength of disorder increases in a wide range of the disorder parameter. In other words, the Anderson localization of incident p waves can be weakened by disorder in a certain parameter regime.

Hydromagnetic nonlinear thermally radiative nanoliquid flow with Newtonian heat and mass conditions

Directory of Open Access Journals (Sweden)

Muhammad Ijaz Khan

Full Text Available This paper communicates the analysis of MHD three-dimensional flow of Jeffrey nanoliquid over a stretchable surface. Flow due to a bidirectional surface is considered. Heat and mass transfer subject to volume fraction of nanoparticles, heat generation and nonlinear solar radiation are examined. Newtonian heat and mass transportation conditions are employed at surface. Concept of boundary layer is utilized to developed the mathematical problem. The boundary value problem is dictated by ten physical parameters: Deborah number, Hartman number, ratio of stretching rates, thermophoretic parameter, Brownian motion parameter, Prandtl number, temperature ratio parameter, conjugate heat and mass parameters and Lewis number. Convergent solutions are obtained using homotopic procedure. Convergence zone for obtained results is explicitly identified. The obtained solutions are interpreted physically. Keywords: Hydromagnetic flow, Viscoelastic nanofluid, Thermophoretic and Brownian moment, Nonlinear thermal radiation, Heat generation

Viscous potential flow analysis of magnetohydrodynamic interfacial stability through porous media

International Nuclear Information System (INIS)

Obied Allah, M.H.

2013-01-01

In the view of viscous potential flow theory, the hydromagnetic stability of the interface between two infinitely conducting, incompressible plasmas, streaming parallel to the interface and subjected to a constant magnetic field parallel to the streaming direction will be considered. The plasmas are flowing through porous media between two rigid planes and surface tension is taken into account. A general dispersion relation is obtained analytically and solved numerically. For Kelvin-Helmholtz instability problem, the stability criterion is given by a critical value of the relative velocity. On the other hand, a comparison between inviscid and viscous potential flow solutions has been made and it has noticed that viscosity plays a dual role, destabilizing for Rayleigh-Taylor problem and stabilizing for Kelvin-Helmholtz. For Rayleigh-Taylor instability, a new dispersion relation has been obtained in terms of a critical wave number. It has been found that magnetic field, surface tension, and rigid planes have stabilizing effects, whereas critical wave number and porous media have destabilizing effects. (author)

Two-dimensional simulation of the hydromagnetic Rayleigh-Taylor instability in an imploding foil plasma

International Nuclear Information System (INIS)

Roderick, N.F.; Hussey, T.W.; Faehl, R.J.; Boyd, R.W.

1978-01-01

Two-dimensional (r-z) magnetohydrodynamic simulations of the electromagnetic implosion of metallic foil plasmas show, for certain initial configurations, a tendency to develop large-amplitude perturbations characteristic of the hydromagnetic Rayleigh-Taylor instability. These perturbations develop at the plasma magnetic field interface for plasma configurations where the density gradient scale length, the characteristic dimension for the instability, is short. The effects on the plasma dynamics of the implosion will be discussed for several initial foil configurations. In general, the growth rates and linear mode structure are found to be influenced by the plasma shell thickness and density gradient scale length, in agreement with theory. The most destructive modes are found to be those with wavelengths of the order of the plasma shell thickness

Antennas in inhomogeneous media

CERN Document Server

Galejs, Janis; Fock, V A; Wait, J R

2013-01-01

Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

Potential flow model for the hydromagnetic Rayleigh--Taylor instability in cylindrical plasmas

International Nuclear Information System (INIS)

Hwang, C.S.; Roderick, N.F.

1987-01-01

A potential flow model has been developed to study the linear behavior of the hydromagnetic equivalent of the Rayleigh--Taylor instability in imploding cylindrical plasmas. Ordinary differential equations are obtained for both (r,z) and (r,θ) disturbances. The model allows the study of the dynamic effects of the moving plasma on the development of the instability. The perturbation equations separate into a geometric part associated with the motion of the interface and a nongeometric part associated with the stability of the interface. In both planes the geometric part shows growth of perturbations for imploding plasmas. The surface is also unstable in both planes for plasmas being imploded by magnetic fields. Analytic solutions are obtained for constant acceleration. These show that the short wavelength perturbations that are most damaging in the (r,z) plane are not affected by the motion of the interface. In the (r,θ) plane the growth of longer wavelength disturbances is affected by the interface motion

Hall effects on free convection hydromagnetic boundary layer flow of Rivlin-Ericksen fluid past a vertical plate

International Nuclear Information System (INIS)

Jha, P.K.

1986-01-01

An attempt has been made to study the problem of free convection hydromagnetic flow of an elastico-viscous fluid past a porous vertical plate in a rotating frame of reference taking ohmic and viscous dissipations into account in the presence of Hall current. The nature of velocity profile shows the existence of multiple boundary layers. Their 'thickness' is seen to decrease with increasing values of Ekman, Hartman and Prandtl numbers and Hall parameter. The graphical study reveals that the increasing values of Hall parameter and Ekman number (for a fixed large value of Hall parameter) exert opposite influence on the flow. (author). 11 refs., 2 tables

Stable pseudoanalytical computation of electromagnetic fields from arbitrarily-oriented dipoles in cylindrically stratified media

Science.gov (United States)

Moon, Haksu; Teixeira, Fernando L.; Donderici, Burkay

2014-09-01

Computation of electromagnetic fields due to point sources (Hertzian dipoles) in cylindrically stratified media is a classical problem for which analytical expressions of the associated tensor Green's function have been long known. However, under finite-precision arithmetic, direct numerical computations based on the application of such analytical (canonical) expressions invariably lead to underflow and overflow problems related to the poor scaling of the eigenfunctions (cylindrical Bessel and Hankel functions) for extreme arguments and/or high-order, as well as convergence problems related to the numerical integration over the spectral wavenumber and to the truncation of the infinite series over the azimuth mode number. These problems are exacerbated when a disparate range of values is to be considered for the layers' thicknesses and material properties (resistivities, permittivities, and permeabilities), the transverse and longitudinal distances between source and observation points, as well as the source frequency. To overcome these challenges in a systematic fashion, we introduce herein different sets of range-conditioned, modified cylindrical functions (in lieu of standard cylindrical eigenfunctions), each associated with nonoverlapped subdomains of (numerical) evaluation to allow for stable computations under any range of physical parameters. In addition, adaptively-chosen integration contours are employed in the complex spectral wavenumber plane to ensure convergent numerical integration in all cases. We illustrate the application of the algorithm to problems of geophysical interest involving layer resistivities ranging from 1000 Ω m to 10-8 Ω m, frequencies of operation ranging from 10 MHz down to the low magnetotelluric range of 0.01 Hz, and for various combinations of layer thicknesses.

Reflection and transmission of electromagnetic waves in planarly stratified media

International Nuclear Information System (INIS)

Caviglia, G.

1999-01-01

Propagation of time-harmonic electromagnetic waves in planarly stratified multilayers is investigated. Each layer is allowed to be inhomogeneous and the layers are separated by interfaces. The procedure is based on the representation of the electromagnetic field in the basis of the eigenvectors of the matrix characterizing the first-order system. Hence the local reflection and transmission matrices are defined and the corresponding differential equations, in the pertinent space variable are determined. The jump conditions at interfaces are also established. The present model incorporates dissipative materials and the procedure holds without any restrictions to material symmetries. Differential equations appeared in the literature are shown to hold in particular (one-dimensional) cases or to represent homogeneous layers only

Induced Electromagnetic Field by Seismic Waves in Stratified Media in Earth's Magnetic Field

Science.gov (United States)

Yamazaki, K.

2017-12-01

Seismic waves accompany electromagnetic (EM) variations because Earth's crust involves a variety of EM properties such as finite electrical conductivity and ion contents. If we can catch the EM variations just after the earthquake rupture, we will know the occurrence of earthquake before the arrival of seismic waves at observation point. However, quantitative aspects of EM variations arising from seismic waves have not sufficiently understood. Together with observational works, theoretical works have been made to simulate EM variations arising from seismic waves. The generation mechanisms of EM variations include electrokinetic effect (Pride, 1994), motional induction (Gao et al., 2014), piezo-electric effect (Ogawa and Utada, 2000), piezo-magnetic effect (Yamazaki, 2016), etc. It is widely accepted that the electrokinetic effect is the dominant mechanism. Theoretical calculation of EM variations assuming the electrokinetic effect roughly explains the observed EM variations accompanying with earthquake ground motions (e.g. Gao et al. 2016). However, there are a significant disagreement between observed and predicted EM variations. In the present study, I focus on the motional induction mechanism that possibly explain some parts of EM variations accompanying with seismic waves. A theoretical work on EM variations arising from the motional induction has been presented by Gao et al. (2014), but their work assumed uniform full-space medium. In contrast, the present work assumes stratified media which correctly incorporate the effect of the ground surface. I apply a calculating method developed in seismology (e.g. Kennett, 2013) and in EM studies (Haartsen and Pride, 1997), and derive a set of expressions describing the spatial-temporal variations of the EM field after the onset of rupture. The derived formula is used to calculate EM variations for actual earthquakes to compare the theoretical prediction to observed EM variations.

The mutual attraction of magnetic knots. [solar hydromagnetic instability in sunspot regions

Science.gov (United States)

Parker, E. N.

1978-01-01

It is observed that the magnetic knots associated with active regions on the sun have an attraction for each other during the formative period of the active regions, when new magnetic flux is coming to the surface. The attraction disappears when new flux ceases to rise through the surface. Then the magnetic spots and knots tend to come apart, leading to disintegration of the sunspots previously formed. The dissolution of the fields is to be expected, as a consequence of the magnetic repulsion of knots of like polarity and as a consequence of the hydromagnetic exchange instability. The purpose of this paper is to show that the mutual attraction of knots during the formative stages of a sunspot region may be understood as the mutual hydrodynamic attraction of the rising flux tubes. Two rising tubes attract each other, as a consequence of the wake of the leading tube when one is moving behind the other, and as a consequence of the Bernoulli effect when rising side by side.

Hydromagnetic Rayleigh endash Taylor instability in high-velocity gas-puff implosions

International Nuclear Information System (INIS)

Roderick, N.F.; Peterkin, R.E. Jr.; Hussey, T.W.; Spielman, R.B.; Douglas, M.R.; Deeney, C.

1998-01-01

Experiments using the Saturn pulsed power generator have produced high-velocity z-pinch plasma implosions with velocities over 100 cm/μs using both annular and uniform-fill gas injection initial conditions. Both types of implosion show evidence of the hydromagnetic Rayleigh endash Taylor instability with the uniform-fill plasmas producing a more spatially uniform pinch. Two-dimensional magnetohydrodynamic simulations including unsteady flow of gas from a nozzle into the diode region have been used to investigate these implosions. The instability develops from the nonuniform gas flow field that forms as the gas expands from the injection nozzle. Instability growth is limited to the narrow unstable region of the current sheath. For the annular puff the unstable region breaks through the inner edge of the annulus increasing nonlinear growth as mass ejected from the bubble regions is not replenished by accretion. This higher growth leads to bubble thinning and disruption producing greater nonuniformity at pinch for the annular puff. The uniform puff provides gas to replenish bubble mass loss until just before pinch resulting in less bubble thinning and a more uniform pinch. copyright 1998 American Institute of Physics

Investigation of single-mode and multi-mode hydromagnetic Rayleigh-Taylor instability in planar geometry

International Nuclear Information System (INIS)

Roderick, N.F.; Cochrane, K.; Douglas, M.R.

1998-01-01

Previous investigations carried out to study various methods of seeding the hydromagnetic Rayleigh-Taylor instability in magnetohydrodynamic simulations showed features similar to those seen in hydrodynamic calculations. For periodic single-mode initiations the results showed the appearance of harmonics as the single modes became nonlinear. For periodic multi-mode initiations new modes developed that indicated the presence of mode coupling. The MHD simulations used parameters of the high velocity large radius z-pinch experiments performed in the Z-accelerator at Sandia National Laboratories. The cylindrical convergent geometry and variable acceleration of these configurations made comparison with analytic, developed for planar geometry with constant acceleration, difficult. A set of calculations in planar geometry using constant current to produce acceleration and parameters characteristic of the cylindrical implosions has been performed to allow a better comparison. Results of these calculations, comparison with analytic theory, and comparison with the cylindrical configuration calculations will be discussed

Unsteady Hydromagnetic Flow of Radiating Fluid Past a Convectively Heated Vertical Plate with the Navier Slip

Directory of Open Access Journals (Sweden)

O. D. Makinde

2014-01-01

Full Text Available This paper investigates the unsteady hydromagnetic-free convection of an incompressible electrical conducting Boussinesq’s radiating fluid past a moving vertical plate in an optically thin environment with the Navier slip, viscous dissipation, and Ohmic and Newtonian heating. The nonlinear partial differential equations governing the transient problem are obtained and tackled numerically using a semidiscretization finite difference method coupled with Runge-Kutta Fehlberg integration technique. Numerical data for the local skin friction coefficient and the Nusselt number have been tabulated for various values of parametric conditions. Graphical results for the fluid velocity, temperature, skin friction, and the Nusselt number are presented and discussed. The results indicate that the skin friction coefficient decreases while the heat transfer rate at the plate surface increases as the slip parameter and Newtonian heating increase.

Upscaling of Two-Phase Immiscible Flows in Communicating Stratified Reservoirs

DEFF Research Database (Denmark)

Zhang, Xuan; Shapiro, Alexander; Stenby, Erling Halfdan

2011-01-01

A semi-analytical method for upscaling two-phase immiscible flows in heterogeneous porous media is described. This method is developed for stratified reservoirs with perfect communication between layers (the case of vertical equilibrium), in a viscous dominant regime, where the effects of capillary...... forces and gravity may be neglected. The method is discussed on the example of its basic application: waterflooding in petroleum reservoirs. We apply asymptotic analysis to a system of two-dimensional (2D) mass conservation equations for incompressible fluids. For high anisotropy ratios, the pressure...... and piston-like displacement, and it presumes non-zero exchange between layers. The method generalizes also the study of Yortsos (Transp Porous Media 18:107–129, 1995), taking into account in a more consistent way the interactions between the layers....

On the Application of the Fourier Series Solution to the Hydromagnetic Buoyant Two-Dimensional Laminar Vertical Jet

Directory of Open Access Journals (Sweden)

Marco Rosales-Vera

2012-01-01

Full Text Available The problem of a hydromagnetic hot two-dimensional laminar jet issuing vertically into an otherwise quiescent fluid of a lower temperature is studied. We propose solutions to the boundary layer equations using the classical Fourier series. The method is essentiall to transform the boundary layer equations to a coupled set of nonlinear first-order ordinary differential equations through the Fourier series. The accuracy of the results has been tested by the comparison of the velocity distributions obtained by the Fourier series with those calculated by finite difference method. The results show that the present method, based on the Fourier series, is an efficient method, suitable to solve boundary layer equations applied to plane jet flows with high accuracy.

Oblique propagation of nonlinear hydromagnetic waves: One- and two-dimensional behavior

International Nuclear Information System (INIS)

Malara, F.; Elaoufir, J.

1991-01-01

The one- and two-dimensional behavior of obliquely propagating hydromagnetic waves is analyzed by means of analytical theory and numerical simulations. It is shown that the nonlinear evolution of a one-dimensional MHD wave leads to the formation of a rotational discontinuity and a compressive steepened quasi-linearly polarized pulse whose structure is similar to that of a finite amplitude magnetosonic simple wave. For small propagation angles, the pulse mode (fast or slow) depends on the value of β with respect to unity while for large propagation angles the wave mode is fixed by the sign of the initial density-field correlation. The two-dimensional evolution shows that an MHD wave is unstable against a small-amplitude long-wavelength modulation in the direction transverse to the wave propagation direction. A two-dimensional magnetosonic wave solution is found, in which the density fluctuation is driven by the corresponding total pressure fluctuation, exactly as in the one-dimensional simple wave. Along with the steepening effect, the wave experiences both wave front deformation and a self-focusing effect which may eventually lead to the collapse of the wave. The results compare well with observations of MHD waves in the Earth's foreshock and at comets

Irreversibility analysis of hydromagnetic flow of couple stress fluid with radiative heat in a channel filled with a porous medium

Directory of Open Access Journals (Sweden)

A.S. Eegunjobi

Full Text Available Numerical analysis of the intrinsic irreversibility of a mixed convection hydromagnetic flow of an electrically conducting couple stress fluid through upright channel filled with a saturated porous medium and radiative heat transfer was carried out. The thermodynamics first and second laws were employed to examine the problem. We obtained the dimensionless nonlinear differential equations and solves numerically with shooting procedure joined with a fourth order Runge-Kutta-Fehlberg integration scheme. The temperature and velocity obtained, used to analyse the entropy generation rate together with some various physical parameters of the flow. Our results are presented graphically and talk over. Keywords: MHD channel flow, Couple stress fluid, Porous medium, Thermal radiation, Entropy generation, Injection/suction

Dynamic shear stabilization of hydromagnetic instabilities in low-beta plasma column by a frequency near the ion cyclotron frequency

International Nuclear Information System (INIS)

Minami, Kazuo; Sato, Kazunori.

1978-09-01

The dynamic shear stabilization of the hydromagnetic instability in low-beta plasmas by an axial RF current whose frequency is not much smaller than the ion cyclotron frequency ωsub(ci) is analyzed in some detail. We adopt the simple model of a uniform plasma column with infinite conductivity. Attention is limited to the case of the m = 1 kink mode with long wave lengths. The Mathieu equation, in which the effect of the ion cyclotron motion is taken into account, is derived. It is shown that the dynamic shear stabilization is still effective, even if the frequency of the applied RF current is of the order of ωsub(ci), which is considerably higher than the frequencies believed to be available in the previous analyses. (author)

Nonlinear two-fluid hydromagnetic waves in the solar wind: Rotational discontinuity, soliton, and finite-extent Alfven wave train solutions

International Nuclear Information System (INIS)

Lyu, L.H.; Kan, J.R.

1989-01-01

Nonlinear one-dimensional constant-profile hydromagnetic wave solutions are obtained in finite-temperature two-fluid collisionless plasmas under adiabatic equation of state. The nonlinear wave solutions can be classified according to the wavelength. The long-wavelength solutions are circularly polarized incompressible oblique Alfven wave trains with wavelength greater than hudreds of ion inertial length. The oblique wave train solutions can explain the high degree of alignment between the local average magnetic field and the wave normal direction observed in the solar wind. The short-wavelength solutions include rarefaction fast solitons, compression slow solitons, Alfven solitons and rotational discontinuities, with wavelength of several tens of ion inertial length, provided that the upstream flow speed is less than the fast-mode speed

Aligned Magnetic Field, Radiation, and Rotation Effects on Unsteady Hydromagnetic Free Convection Flow Past an Impulsively Moving Vertical Plate in a Porous Medium

Directory of Open Access Journals (Sweden)

Sandeep Naramgari

2014-01-01

Full Text Available We analyse the effects of aligned magnetic field, radiation, and rotation on unsteady hydromagnetic free convection flow of a viscous incompressible electrically conducting fluid past an impulsively moving vertical plate in a porous medium in presence of heat source. An exact solution of the governing equations in dimensionless form is obtained by Laplace transform technique in ramped temperature case. To compare the results obtained in this case with that of isothermal plate, the exact solution of the governing equations is also obtained for isothermal plate and results are discussed graphically in both ramped temperature and isothermal cases.

Keratinocytes propagated in serum-free, feeder-free culture conditions fail to form stratified epidermis in a reconstituted skin model.

Directory of Open Access Journals (Sweden)

Rebecca Lamb

Full Text Available Primary human epidermal stem cells isolated from skin tissues and subsequently expanded in tissue culture are used for human therapeutic use to reconstitute skin on patients and to generate artificial skin in culture for academic and commercial research. Classically, epidermal cells, known as keratinocytes, required fibroblast feeder support and serum-containing media for serial propagation. In alignment with global efforts to remove potential animal contaminants, many serum-free, feeder-free culture methods have been developed that support derivation and growth of these cells in 2-dimensional culture. Here we show that keratinocytes grown continually in serum-free and feeder-free conditions were unable to form into a stratified, mature epidermis in a skin equivalent model. This is not due to loss of cell potential as keratinocytes propagated in serum-free, feeder-free conditions retain their ability to form stratified epidermis when re-introduced to classic serum-containing media. Extracellular calcium supplementation failed to improve epidermis development. In contrast, the addition of serum to commercial, growth media developed for serum-free expansion of keratinocytes facilitated 3-dimensional stratification in our skin equivalent model. Moreover, the addition of heat-inactivated serum improved the epidermis structure and thickness, suggesting that serum contains factors that both aid and inhibit stratification.

Magnetic superstorm on August 4-5, 1972 in connection with a hydromagnetic structure of the interplanetary plasma stream from a powerful flare

International Nuclear Information System (INIS)

Ivanov, K.G.; Mikerina, N.V.

1977-01-01

A comparison is made between the hydromagnetic structure of the interplanetary plasma flux from the powerful solar flare occurred on 4.08.1972 and the magnetic storm of 4-5.08.1972. The geomagnetic effects of the head impact layer of the interplanetary flux are being considered. The world-wide disturbances being most intensive in the Polar regions corresponded to the elements of the substructure of the impact layer. These disturbances are interpreted as the superposition of magnetic fields from reconnection currents on the magnetopause and in the neutral layer of the magnetosphere trail. The qualitative description of the effects under investigation has been made on the assumption that the magnetopause is a rotational impact wave

Analytical solutions for hydromagnetic natural convection flow of a particulate suspension through isoflux-isothermal channels in the presence of a heat source or sink

International Nuclear Information System (INIS)

Chamkha, Ali J.; Al-Rashidi, Seham S.

2010-01-01

This work considers the problem of steady natural convection hydromagnetic flow of a particulate suspension through an infinitely long channel in the presence of heat generation or absorption effects. The channel walls are maintained at isoflux-isothermal condition. That is, the thermal boundary conditions are such that one of the channel walls is maintained at constant heat flux while the other is maintained at a constant temperature. Various closed-form solutions of the governing equations for different special cases are obtained. A parametric study of the physical parameters involved in the problem is done to illustrate the influence of these parameters on the velocity and temperature profiles of both phases.

On the propagation of hydromagnetic waves in a plasma of thermal and suprathermal components

Science.gov (United States)

Kumar, Nagendra; Sikka, Himanshu

2007-12-01

The propagation of MHD waves is studied when two ideal fluids, thermal and suprathermal gases, coupled by magnetic field are moving with the steady flow velocity. The fluids move independently in a direction perpendicular to the magnetic field but gets coupled along the field. Due to the presence of flow in suprathermal and thermal fluids there appears forward and backward waves. All the forward and backward modes propagate in such a way that their rate of change of phase speed with the thermal Mach number is same. It is also found that besides the usual hydromagnetic modes there appears a suprathermal mode which propagates with faster speed. Surface waves are also examined on an interface formed with composite plasma (suprathermal and thermal gases) on one side and the other is a non-magnetized plasma. In this case, the modes obtained are two or three depending on whether the sound velocity in thermal gas is equal to or greater than the sound velocity in suprathermal gas. The results lead to the conclusion that the interaction of thermal and suprathermal components may lead to the occurrence of an additional mode called suprathermal mode whose phase velocity is higher than all the other modes.

Spectral transfer functions of body waves propagating through a stratified medium. Part 1: Basic theory by means of matrix propagators

International Nuclear Information System (INIS)

Macia, R.; Correig, A.M.

1987-01-01

Seismic wave propagation is described by a second order differential equation for medium displacement. By Fourier transforming with respect to time and space, wave equation transforms into a system of first order linear differential equations for the Fourier transform of displacement and stress. This system of differential equations is solved by means of Matrix Propagator and applied to the propagation of body waves in stratified media. The matrix propagators corresponding to P-SV and SH waves in homogeneous medium are found as an intermediate step to obtain the spectral response of body waves propagating through a stratified medium with homogeneous layers. (author) 14 refs

Stable evaluation of Green's functions in cylindrically stratified regions with uniaxial anisotropic layers

Science.gov (United States)

Moon, H.; Donderici, B.; Teixeira, F. L.

2016-11-01

We present a robust algorithm for the computation of electromagnetic fields radiated by point sources (Hertzian dipoles) in cylindrically stratified media where each layer may exhibit material properties (permittivity, permeability, and conductivity) with uniaxial anisotropy. Analytical expressions are obtained based on the spectral representation of the tensor Green's function based on cylindrical Bessel and Hankel eigenfunctions, and extended for layered uniaxial media. Due to the poor scaling of these eigenfunctions for extreme arguments and/or orders, direct numerical evaluation of such expressions can produce numerical instability, i.e., underflow, overflow, and/or round-off errors under finite precision arithmetic. To circumvent these problems, we develop a numerically stable formulation through suitable rescaling of various expressions involved in the computational chain, to yield a robust algorithm for all parameter ranges. Numerical results are presented to illustrate the robustness of the formulation including cases of practical interest.

Design of dry sand soil stratified sampler

Science.gov (United States)

Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

2018-04-01

This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

When outcome expectations become habitual : explaining vs. predicting new media technology use from a social cognitive perspective

NARCIS (Netherlands)

Peters, O.

2007-01-01

This study examined the triadic relationship between expected outcomes, habit strength, and media technology use within the model of media attendance (Larose & Eastin, 2004). Mobile phone users (N = 664) were divided into two groups using a stratified random sampling method. Respondents of group one

A Fast MHD Code for Gravitationally Stratified Media using Graphical Processing Units: SMAUG

Science.gov (United States)

Griffiths, M. K.; Fedun, V.; Erdélyi, R.

2015-03-01

Parallelization techniques have been exploited most successfully by the gaming/graphics industry with the adoption of graphical processing units (GPUs), possessing hundreds of processor cores. The opportunity has been recognized by the computational sciences and engineering communities, who have recently harnessed successfully the numerical performance of GPUs. For example, parallel magnetohydrodynamic (MHD) algorithms are important for numerical modelling of highly inhomogeneous solar, astrophysical and geophysical plasmas. Here, we describe the implementation of SMAUG, the Sheffield Magnetohydrodynamics Algorithm Using GPUs. SMAUG is a 1-3D MHD code capable of modelling magnetized and gravitationally stratified plasma. The objective of this paper is to present the numerical methods and techniques used for porting the code to this novel and highly parallel compute architecture. The methods employed are justified by the performance benchmarks and validation results demonstrating that the code successfully simulates the physics for a range of test scenarios including a full 3D realistic model of wave propagation in the solar atmosphere.

The effect of surfactant on stratified and stratifying gas-liquid flows

Science.gov (United States)

Heiles, Baptiste; Zadrazil, Ivan; Matar, Omar

2013-11-01

We consider the dynamics of a stratified/stratifying gas-liquid flow in horizontal tubes. This flow regime is characterised by the thin liquid films that drain under gravity along the pipe interior, forming a pool at the bottom of the tube, and the formation of large-amplitude waves at the gas-liquid interface. This regime is also accompanied by the detachment of droplets from the interface and their entrainment into the gas phase. We carry out an experimental study involving axial- and radial-view photography of the flow, in the presence and absence of surfactant. We show that the effect of surfactant is to reduce significantly the average diameter of the entrained droplets, through a tip-streaming mechanism. We also highlight the influence of surfactant on the characteristics of the interfacial waves, and the pressure gradient that drives the flow. EPSRC Programme Grant EP/K003976/1.

Jovian electron bursts: Correlation with the interplanetary field direction and hydromagnetic waves

International Nuclear Information System (INIS)

Smith, E.J.; Tsurutani, B.T.; Chenette, D.L.; Conlon, T.F.; Simpson, J.A.

1976-01-01

The bursts of relativistic electrons detected on Pioneer 10 upstream from Jupiter and within 400r/subj/ of the planet have been found to be correlated with the interplanetary magnetic field. In the three examples upon which this study is based, during the month prior to the Pioneer 10 encounter, electrons with energies between 3 and 6 MeV escaping from Jupiter's magnetosphere were observed only when the interplanetary magnetic field was along the Jupiter-spacecraft line. In addition, large-amplitude interplanetary waves with characteristic periods of 10 min were observed and found to be well correlated with intervals during which the field was along the Jupiter-spacecraft line. Abrupt changes in the field away from the preferred direction caused equally abrupt terminations of the waves with an accompanying reduction in the electron flux. These results are consistent with propagation of the electrons from Jupiter to Pioneer along, rather than across, the magnetic field lines. The direction of the interplanetary magnetic field is apparently not affected by the electron bursts or by other particles from Jupiter. The average Parker spiral direction is clear with no enhancement in the Jupiter-spacecraft direction. Two alternative possibilities are considered for the origin of the waves. If they were generated near Jupiter, they would have to propagate to the spacecraft in the whistler mode. The expected attenuation of these waves over distances of several hundred r/subj/ an their long travel times make this explanation unattractive. Alternatively, hydromagnetic wave generation by Jovian charged particles, presumably the relativistic electrons themselves, as they travel upstream, appears to be an attractive explanation

Stable evaluation of Green's functions in cylindrically stratified regions with uniaxial anisotropic layers

Energy Technology Data Exchange (ETDEWEB)

Moon, H., E-mail: haksu.moon@gmail.com [ElectroScience Laboratory, The Ohio State University, Columbus, OH 43212 (United States); Donderici, B., E-mail: burkay.donderici@halliburton.com [Sensor Physics & Technology, Halliburton Energy Services, Houston, TX 77032 (United States); Teixeira, F.L., E-mail: teixeira@ece.osu.edu [ElectroScience Laboratory, The Ohio State University, Columbus, OH 43212 (United States)

2016-11-15

We present a robust algorithm for the computation of electromagnetic fields radiated by point sources (Hertzian dipoles) in cylindrically stratified media where each layer may exhibit material properties (permittivity, permeability, and conductivity) with uniaxial anisotropy. Analytical expressions are obtained based on the spectral representation of the tensor Green's function based on cylindrical Bessel and Hankel eigenfunctions, and extended for layered uniaxial media. Due to the poor scaling of these eigenfunctions for extreme arguments and/or orders, direct numerical evaluation of such expressions can produce numerical instability, i.e., underflow, overflow, and/or round-off errors under finite precision arithmetic. To circumvent these problems, we develop a numerically stable formulation through suitable rescaling of various expressions involved in the computational chain, to yield a robust algorithm for all parameter ranges. Numerical results are presented to illustrate the robustness of the formulation including cases of practical interest.

Analysis of Turbulent Combustion in Simplified Stratified Charge Conditions

Science.gov (United States)

Moriyoshi, Yasuo; Morikawa, Hideaki; Komatsu, Eiji

The stratified charge combustion system has been widely studied due to the significant potentials for low fuel consumption rate and low exhaust gas emissions. The fuel-air mixture formation process in a direct-injection stratified charge engine is influenced by various parameters, such as atomization, evaporation, and in-cylinder gas motion at high temperature and high pressure conditions. It is difficult to observe the in-cylinder phenomena in such conditions and also challenging to analyze the following stratified charge combustion. Therefore, the combustion phenomena in simplified stratified charge conditions aiming to analyze the fundamental stratified charge combustion are examined. That is, an experimental apparatus which can control the mixture distribution and the gas motion at ignition timing was developed, and the effects of turbulence intensity, mixture concentration distribution, and mixture composition on stratified charge combustion were examined. As a result, the effects of fuel, charge stratification, and turbulence on combustion characteristics were clarified.

Effective Social Media Engagement for Nonprofits: What Matters?

Directory of Open Access Journals (Sweden)

Julia L Carboni

2015-03-01

Full Text Available We employ public management relationship theory to examine how nonprofits can effectively engage social media stakeholders in two-way communication. Though many nonprofit organizations have a social media presence, there is variance in how well organizations use social media to engage stakeholders. Simply having a social media presence is not enough to engage stakeholders.  We examine Facebook posts of a stratified random sample of youth development organizations to determine what predicts stakeholder engagement. We find the type of Facebook post is a significant predictor of stakeholder engagement.  Longer posts also significantly predict increased stakeholder engagement.  At the organizational level, having many posts is a significant negative predictor of stakeholder engagement, indicating that users may feel bombarded and are less likely to engage.  Increased organizational spending on advertising as a proportion of total budget is positively associated with stakeholder engagement. 

Grain distinct stratified nanolayers in aluminium alloys

Energy Technology Data Exchange (ETDEWEB)

Donatus, U., E-mail: uyimedonatus@yahoo.com [School of Materials, The University of Manchester, Manchester, M13 9PL, England (United Kingdom); Thompson, G.E.; Zhou, X.; Alias, J. [School of Materials, The University of Manchester, Manchester, M13 9PL, England (United Kingdom); Tsai, I.-L. [Oxford Instruments NanoAnalysis, HP12 2SE, High Wycombe (United Kingdom)

2017-02-15

The grains of aluminium alloys have stratified nanolayers which determine their mechanical and chemical responses. In this study, the nanolayers were revealed in the grains of AA6082 (T6 and T7 conditions), AA5083-O and AA2024-T3 alloys by etching the alloys in a solution comprising 20 g Cr{sub 2}O{sub 3} + 30 ml HPO{sub 3} in 1 L H{sub 2}O. Microstructural examination was conducted on selected grains of interest using scanning electron microscopy and electron backscatter diffraction technique. It was observed that the nanolayers are orientation dependent and are parallel to the {100} planes. They have ordered and repeated tunnel squares that are flawed at the sides which are aligned in the <100> directions. These flawed tunnel squares dictate the tunnelling corrosion morphology as well as appearing to have an affect on the arrangement and sizes of the precipitation hardening particles. The inclination of the stratified nanolayers, their interpacing, and the groove sizes have significant influence on the corrosion behaviour and seeming influence on the strengthening mechanism of the investigated aluminium alloys. - Highlights: • Stratified nanolayers in aluminium alloy grains. • Relationship of the stratified nanolayers with grain orientation. • Influence of the inclinations of the stratified nanolayers on corrosion. • Influence of the nanolayers interspacing and groove sizes on hardness and corrosion.

The stratified H-index makes scientific impact transparent

DEFF Research Database (Denmark)

Würtz, Morten; Schmidt, Morten

2017-01-01

The H-index is widely used to quantify and standardize researchers' scientific impact. However, the H-index does not account for the fact that co-authors rarely contribute equally to a paper. Accordingly, we propose the use of a stratified H-index to measure scientific impact. The stratified H......-index supplements the conventional H-index with three separate H-indices: one for first authorships, one for second authorships and one for last authorships. The stratified H-index takes scientific output, quality and individual author contribution into account....

Adenoid ciliostimulation in children with chronic otitis media.

Science.gov (United States)

Andreoli, Steven M; Schlosser, Rodney J; Wang, Ling-Feng; Mulligan, Ryan M; Discolo, Christopher M; White, David R

2013-01-01

Adenoid hypertrophy and chronic adenoiditis are associated with an increased incidence of chronic otitis media. This study intends to determine the relationship between chronic otitis media and dynamic ciliary beat frequency in children undergoing adenoidectomy. Prospective, controlled study. Pediatric tertiary care hospital. Children undergoing adenoidectomy were enrolled. Patients were stratified according to their indication for surgery, including adenotonsillar hypertrophy with obstructive sleep apnea, chronic otitis media with effusion, or recurrent episodes of acute otitis media. Adenoids were harvested using the curette. Tissue was sectioned and allowed to equilibrate in basal media for 24 hours. Cilia-bearing tissue was then stimulated using isoproterenol or methacholine. Ciliary beat frequency was serially reordered and analyzed using the Sisson-Ammons Video Analysis software program. Baseline ciliary beat frequency was similar in all groups (N = 47, total). Using isoproterenol, children with chronic otitis media with effusion demonstrated a blunted dynamic ciliary response at 2 and 3 hours relative to control (P = .0176 and P = .0282). Methacholine-stimulated ciliary beat frequency was not different between each group. At 2 and 3 hours following isoproterenol stimulation, there was a significant blunting of dynamic ciliary beat frequency in children with chronic otitis media with effusion. This ciliary dysfunction may provide a physiological explanation related to chronic adenoiditis in children with chronic otitis media.

Newtonian heating effect on unsteady hydromagnetic Casson fluid flow past a flat plate with heat and mass transfer

Directory of Open Access Journals (Sweden)

M. Das

2015-12-01

Full Text Available The influence of Newtonian heating on heat and mass transfer in unsteady hydromagnetic flow of a Casson fluid past a vertical plate in the presence of thermal radiation and chemical reaction is studied. The Casson fluid model is used to distinguish the non-Newtonian fluid behavior. The fluid flow is induced due to periodic oscillations of the plate along its length and a uniform transverse magnetic field is applied in a direction which is normal to the direction of fluid flow. The partial differential equations governing the flow, heat, and mass transfer are transformed to non-dimensional form using suitable non-dimensional variables which are then solved analytically by using Laplace transform technique. The numerical values of the fluid velocity, fluid temperature, and species concentration are depicted graphically whereas the values of skin-friction, Nusselt number, and Sherwood number are presented in tabular form. It is noticed that the fluid velocity and temperature decrease with increasing values of Casson parameter while concentration decreases with increasing values of chemical reaction parameter and Schmidt number. Such a fluid flow model has several industrial and medical applications such as in glass manufacturing, paper production, purification of crude oil and study of blood flow in the cardiovascular system.

A chemically defined culture medium containing Rho kinase inhibitor Y-27632 for the fabrication of stratified squamous epithelial cell grafts

International Nuclear Information System (INIS)

Aslanova, Afag; Takagi, Ryo; Yamato, Masayuki; Okano, Teruo; Yamamoto, Masakazu

2015-01-01

With the development of a culture method for stratified squamous epithelial cells, tissue-engineered epithelial cell sheets have been successfully applied as clinical cell grafts. However, the implementation of these cell sheets without the use of any animal-derived materials is highly desirable. In this study, Rho-associated protein kinase inhibitor Y-27632 was used to develop a chemically defined culture medium for the fabrication of stratified epithelial cell grafts consisting of human epidermal and oral keratinocytes, and the proliferation activity, cell morphology, and gene expressions of the keratinocytes were analyzed. The results of a colorimetric assay indicated that Y-27632 significantly promoted the proliferation of the keratinocytes in culture media both with and without fetal bovine serum (FBS), although there were no indications of Y-27632 efficacy on cell morphology and stratification of the keratinocytes in culture medium without any animal-derived materials. The results of quantitative RT-PCR revealed that gene expressions correlated with cell adhesion, cell–cell junction, proliferation markers, and stem/progenitor markers in cultured keratinocytes were not strongly affected by the addition of Y-27632 to the culture medium. Moreover, gene expressions of differentiation markers in stratified keratinocytes cultured in medium without FBS were nearly identical to those of keratinocytes co-cultured with 3T3 feeder cells. Interestingly, the expressions of differentiation markers in cultured stratified keratinocytes were suppressed by FBS, whereas they were reconstructed by either co-culture of a 3T3 feeder layer or addition of Y-27632 into the culture medium containing FBS. These findings indicate that Y-27632 is a useful supplement for the development of a chemically defined culture medium for fabrication of stratified epithelial cell grafts for clinical applications for the purpose of developing the culture medium with a lower risk of pathogen

A chemically defined culture medium containing Rho kinase inhibitor Y-27632 for the fabrication of stratified squamous epithelial cell grafts

Energy Technology Data Exchange (ETDEWEB)

Aslanova, Afag [Department of Surgery, Institute of Gastroenterology, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Institute of Advanced Biomedical Engineering and Science, Tokyo Women' s Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Takagi, Ryo; Yamato, Masayuki; Okano, Teruo [Institute of Advanced Biomedical Engineering and Science, Tokyo Women' s Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Yamamoto, Masakazu, E-mail: yamamoto.ige@twmu.ac.jp [Department of Surgery, Institute of Gastroenterology, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan)

2015-05-01

With the development of a culture method for stratified squamous epithelial cells, tissue-engineered epithelial cell sheets have been successfully applied as clinical cell grafts. However, the implementation of these cell sheets without the use of any animal-derived materials is highly desirable. In this study, Rho-associated protein kinase inhibitor Y-27632 was used to develop a chemically defined culture medium for the fabrication of stratified epithelial cell grafts consisting of human epidermal and oral keratinocytes, and the proliferation activity, cell morphology, and gene expressions of the keratinocytes were analyzed. The results of a colorimetric assay indicated that Y-27632 significantly promoted the proliferation of the keratinocytes in culture media both with and without fetal bovine serum (FBS), although there were no indications of Y-27632 efficacy on cell morphology and stratification of the keratinocytes in culture medium without any animal-derived materials. The results of quantitative RT-PCR revealed that gene expressions correlated with cell adhesion, cell–cell junction, proliferation markers, and stem/progenitor markers in cultured keratinocytes were not strongly affected by the addition of Y-27632 to the culture medium. Moreover, gene expressions of differentiation markers in stratified keratinocytes cultured in medium without FBS were nearly identical to those of keratinocytes co-cultured with 3T3 feeder cells. Interestingly, the expressions of differentiation markers in cultured stratified keratinocytes were suppressed by FBS, whereas they were reconstructed by either co-culture of a 3T3 feeder layer or addition of Y-27632 into the culture medium containing FBS. These findings indicate that Y-27632 is a useful supplement for the development of a chemically defined culture medium for fabrication of stratified epithelial cell grafts for clinical applications for the purpose of developing the culture medium with a lower risk of pathogen

Exploring the role of wave drag in the stable stratified oceanic and atmospheric bottom boundary layer in the cnrs-toulouse (cnrm-game) large stratified water flume

NARCIS (Netherlands)

Kleczek, M.; Steeneveld, G.J.; Paci, A.; Calmer, R.; Belleudy, A.; Canonici, J.C.; Murguet, F.; Valette, V.

2014-01-01

This paper reports on a laboratory experiment in the CNRM-GAME (Toulouse) stratified water flume of a stably stratified boundary layer, in order to quantify the momentum transfer due to orographically induced gravity waves by gently undulating hills in a boundary layer flow. In a stratified fluid, a

Finite-time singularities and flow regularization in a hydromagnetic shell model at extreme magnetic Prandtl numbers

International Nuclear Information System (INIS)

Nigro, G; Carbone, V

2015-01-01

Conventional surveys on the existence of singularities in fluid systems for vanishing dissipation have hitherto tried to infer some insight by searching for spatial features developing in asymptotic regimes. This approach has not yet produced a conclusive answer. One of the difficulties preventing us from getting a definitive answer is the limitations of direct numerical simulations which do not yet have a high enough resolution so far as to properly describe spatial fine structures in asymptotic regimes. In this paper, instead of searching for spatial details, we suggest seeking a principle, that would be able to discriminate between singular or not-singular behavior, among the integral and purely dynamical properties of a fluid system. We investigate the singularities developed by a hydromagnetic shell model during the magnetohydrodynamic turbulent cascade. Our results show that when the viscosity is equal to the magnetic diffusivity (unit magnetic Prandtl number) singularities appear in a finite time. A complex behavior is observed at extreme magnetic Prandtl numbers. In particular, the singularities persist in the limit of vanishing viscosity, while a complete regularization is observed in the limit of vanishing diffusivity. This dynamics is related to differences between the magnetic and the kinetic energy cascades towards small scales. Finally a comparison between the three-dimensional and the two-dimensional cases leads to conjecture that the existence of singularities may be related to the conservation of different ideal invariants. (paper)

Social Media in Pediatric Orthopaedics.

Science.gov (United States)

Lander, Sarah T; Sanders, James O; Cook, Peter C; O'Malley, Natasha T

Internet searches and social media utilization in health care has exploded over the past 5 years, and patients utilize it to gain information on their health conditions and physicians. Social media has the potential to serve as a means for education, communication, and marketing in all health care specialties. Physicians are sometimes reluctant to engage because of concerns of privacy, litigation, and lack of experience with this modality. Many surgical subspecialties have capitalized on social media but no study to date has examined the specific footprint of pediatric orthopaedic surgeons in this realm. We aim to quantify the utilization of individual social media platforms by pediatric orthopaedic surgeons, and identify any differences between private and hospital-based physicians, but also regional differences. Using the Pediatric Orthopaedic Society of North America Member Directory, each active member's social media presence was reviewed through an Internet search. Members were stratified on the basis of practice model and geographic location. Individual Internet searches, social media sites, and number of publications were reviewed for social media presence. Of 987 Pediatric Orthopaedic Society of North America members, 95% had a professional webpage, 14.8% a professional Facebook page, 2.2% a professional Twitter page, 36.8% a LinkedIn profile, 25.8% a ResearchGate profile, 33% at least 1 YouTube. Hospital-based physicians had a lower mean level of utilization of social media compared with their private practice peers, and a higher incidence of Pubmed publications. Private practice physicians had double the social media utilization. Regional differences reveal that practicing Pediatric Orthopaedists in the Northeast had increased utilization of ResearchGate and LinkedIn and the West had the lowest mean social media utilization levels. The rapid expansion of social media usage by patients and their family members is an undeniable force affecting the health

Relationships of the phase velocity with the microarchitectural parameters in bovine trabecular bone in vitro: Application of a stratified model

Science.gov (United States)

Lee, Kang Il

2012-08-01

The present study aims to provide insight into the relationships of the phase velocity with the microarchitectural parameters in bovine trabecular bone in vitro. The frequency-dependent phase velocity was measured in 22 bovine femoral trabecular bone samples by using a pair of transducers with a diameter of 25.4 mm and a center frequency of 0.5 MHz. The phase velocity exhibited positive correlation coefficients of 0.48 and 0.32 with the ratio of bone volume to total volume and the trabecular thickness, respectively, but a negative correlation coefficient of -0.62 with the trabecular separation. The best univariate predictor of the phase velocity was the trabecular separation, yielding an adjusted squared correlation coefficient of 0.36. The multivariate regression models yielded adjusted squared correlation coefficients of 0.21-0.36. The theoretical phase velocity predicted by using a stratified model for wave propagation in periodically stratified media consisting of alternating parallel solid-fluid layers showed reasonable agreements with the experimental measurements.

Aligning the Economic Value of Companion Diagnostics and Stratified Medicines

Directory of Open Access Journals (Sweden)

Edward D. Blair

2012-11-01

Full Text Available The twin forces of payors seeking fair pricing and the rising costs of developing new medicines has driven a closer relationship between pharmaceutical companies and diagnostics companies, because stratified medicines, guided by companion diagnostics, offer better commercial, as well as clinical, outcomes. Stratified medicines have created clinical success and provided rapid product approvals, particularly in oncology, and indeed have changed the dynamic between drug and diagnostic developers. The commercial payback for such partnerships offered by stratified medicines has been less well articulated, but this has shifted as the benefits in risk management, pricing and value creation for all stakeholders become clearer. In this larger healthcare setting, stratified medicine provides both physicians and patients with greater insight on the disease and provides rationale for providers to understand cost-effectiveness of treatment. This article considers how the economic value of stratified medicine relationships can be recognized and translated into better outcomes for all healthcare stakeholders.

Large eddy simulation of stably stratified turbulence

International Nuclear Information System (INIS)

Shen Zhi; Zhang Zhaoshun; Cui Guixiang; Xu Chunxiao

2011-01-01

Stably stratified turbulence is a common phenomenon in atmosphere and ocean. In this paper the large eddy simulation is utilized for investigating homogeneous stably stratified turbulence numerically at Reynolds number Re = uL/v = 10 2 ∼10 3 and Froude number Fr = u/NL = 10 −2 ∼10 0 in which u is root mean square of velocity fluctuations, L is integral scale and N is Brunt-Vaïsälä frequency. Three sets of computation cases are designed with different initial conditions, namely isotropic turbulence, Taylor Green vortex and internal waves, to investigate the statistical properties from different origins. The computed horizontal and vertical energy spectra are consistent with observation in atmosphere and ocean when the composite parameter ReFr 2 is greater than O(1). It has also been found in this paper that the stratification turbulence can be developed under different initial velocity conditions and the internal wave energy is dominated in the developed stably stratified turbulence.

Stratified medicine and reimbursement issues

NARCIS (Netherlands)

Fugel, Hans-Joerg; Nuijten, Mark; Postma, Maarten

2012-01-01

Stratified Medicine (SM) has the potential to target patient populations who will most benefit from a therapy while reducing unnecessary health interventions associated with side effects. The link between clinical biomarkers/diagnostics and therapies provides new opportunities for value creation to

The Stratified Legitimacy of Abortions.

Science.gov (United States)

Kimport, Katrina; Weitz, Tracy A; Freedman, Lori

2016-12-01

Roe v. Wade was heralded as an end to unequal access to abortion care in the United States. However, today, despite being common and safe, abortion is performed only selectively in hospitals and private practices. Drawing on 61 interviews with obstetrician-gynecologists in these settings, we examine how they determine which abortions to perform. We find that they distinguish between more and less legitimate abortions, producing a narrative of stratified legitimacy that privileges abortions for intended pregnancies, when the fetus is unhealthy, and when women perform normative gendered sexuality, including distress about the abortion, guilt about failure to contracept, and desire for motherhood. This stratified legitimacy can perpetuate socially-inflected inequality of access and normative gendered sexuality. Additionally, we argue that the practice by physicians of distinguishing among abortions can legitimate legislative practices that regulate and restrict some kinds of abortion, further constraining abortion access. © American Sociological Association 2016.

Stratified charge rotary engine for general aviation

Science.gov (United States)

Mount, R. E.; Parente, A. M.; Hady, W. F.

1986-01-01

A development history, a current development status assessment, and a design feature and performance capabilities account are given for stratified-charge rotary engines applicable to aircraft propulsion. Such engines are capable of operating on Jet-A fuel with substantial cost savings, improved altitude capability, and lower fuel consumption by comparison with gas turbine powerplants. Attention is given to the current development program of a 400-hp engine scheduled for initial operations in early 1990. Stratified charge rotary engines are also applicable to ground power units, airborne APUs, shipboard generators, and vehicular engines.

Relationships of the phase velocity with the micro architectural parameters in bovine trabecular bone in vitro: application of a stratified model

Energy Technology Data Exchange (ETDEWEB)

Lee, Kang Il [Kangwon National University, Chuncheon (Korea, Republic of)

2012-08-15

The present study aims to provide insight into the relationships of the phase velocity with the micro architectural parameters in bovine trabecular bone in vitro. The frequency-dependent phase velocity was measured in 22 bovine femoral trabecular bone samples by using a pair of transducers with a diameter of 25.4 mm and a center frequency of 0.5 MHz. The phase velocity exhibited positive correlation coefficients of 0.48 and 0.32 with the ratio of bone volume to total volume and the trabecular thickness, respectively, but a negative correlation coefficient of -0.62 with the trabecular separation. The best univariate predictor of the phase velocity was the trabecular separation, yielding an adjusted squared correlation coefficient of 0.36. The multivariate regression models yielded adjusted squared correlation coefficients of 0.21 - 0.36. The theoretical phase velocity predicted by using a stratified model for wave propagation in periodically stratified media consisting of alternating parallel solid-fluid layers showed reasonable agreements with the experimental measurements.

Relationships of the phase velocity with the micro architectural parameters in bovine trabecular bone in vitro: application of a stratified model

International Nuclear Information System (INIS)

Lee, Kang Il

2012-01-01

The present study aims to provide insight into the relationships of the phase velocity with the micro architectural parameters in bovine trabecular bone in vitro. The frequency-dependent phase velocity was measured in 22 bovine femoral trabecular bone samples by using a pair of transducers with a diameter of 25.4 mm and a center frequency of 0.5 MHz. The phase velocity exhibited positive correlation coefficients of 0.48 and 0.32 with the ratio of bone volume to total volume and the trabecular thickness, respectively, but a negative correlation coefficient of -0.62 with the trabecular separation. The best univariate predictor of the phase velocity was the trabecular separation, yielding an adjusted squared correlation coefficient of 0.36. The multivariate regression models yielded adjusted squared correlation coefficients of 0.21 - 0.36. The theoretical phase velocity predicted by using a stratified model for wave propagation in periodically stratified media consisting of alternating parallel solid-fluid layers showed reasonable agreements with the experimental measurements.

Media Portrayals of Female Perpetrators of Intimate Partner Violence.

Science.gov (United States)

Carlyle, Kellie E; Scarduzio, Jennifer A; Slater, Michael D

2014-09-01

Preventing intimate partner violence (IPV) is a public health priority. An important component of designing prevention programs is developing an understanding of how media portrayals of health issues influence public opinion and policy. To better understand the ways in which media images may be informing our understanding of IPV, this study content analyzed portrayals of IPV in news media articles. Stratified media outlets were used to obtain a representative sample of daily newspapers based on their designated market areas. Researchers created constructed months using weeks from each season across a 2-year period. The first part of the study investigated quantitative differences in the coverage of female and male perpetrators (n = 395) and identified several areas where coverage differed. The second part of the study qualitatively examined coverage of female perpetrators (n = 61) to provide a richer description of such coverage. This study contributes to our understanding of female perpetrators and how these portrayals may contribute to the larger gender symmetry debate surrounding female aggressors. Implications for public health policy and research are discussed. © The Author(s) 2014.

Nitrogen transformations in stratified aquatic microbial ecosystems

DEFF Research Database (Denmark)

Revsbech, Niels Peter; Risgaard-Petersen, N.; Schramm, Andreas

2006-01-01

Abstract  New analytical methods such as advanced molecular techniques and microsensors have resulted in new insights about how nitrogen transformations in stratified microbial systems such as sediments and biofilms are regulated at a µm-mm scale. A large and ever-expanding knowledge base about n...... performing dissimilatory reduction of nitrate to ammonium have given new dimensions to the understanding of nitrogen cycling in nature, and the occurrence of these organisms and processes in stratified microbial communities will be described in detail.......Abstract  New analytical methods such as advanced molecular techniques and microsensors have resulted in new insights about how nitrogen transformations in stratified microbial systems such as sediments and biofilms are regulated at a µm-mm scale. A large and ever-expanding knowledge base about...... nitrogen fixation, nitrification, denitrification, and dissimilatory reduction of nitrate to ammonium, and about the microorganisms performing the processes, has been produced by use of these techniques. During the last decade the discovery of anammmox bacteria and migrating, nitrate accumulating bacteria...

The effects of ventilation tubes versus no ventilation tubes for recurrent acute otitis media or chronic otitis media with effusion in 9 to 36 month old Greenlandic children, the SIUTIT trial

DEFF Research Database (Denmark)

Demant, Malene Nøhr; Jensen, Ramon Gordon; Jakobsen, Janus Christian

2017-01-01

BACKGROUND: The prevalence of otitis media in Greenlandic children is one of the highest in the world. International studies have shown that otitis-prone children may benefit from tubulation of the tympanic membrane. However, it is unknown whether these results can be applied to Greenlandic......) in Greenlandic children aged 9-36 months with chronic otitis media with effusion or recurrent acute otitis media. With randomization stratified by otitis media subtype and trial site, a type 1 error of 5% and a power of 80%, a total of 230 participants are needed to detect a decrease of two visits to a health...... clinic during 2 years, which is considered the minimal clinical relevant difference. The primary outcome measure will be assessed blindly by investigating medical records. Secondary outcome measures are number of episodes of acute otitis media, quality of life, number of episodes of antibiotics...

The DC field components of horizontal and vertical electric dipole sources immersed in three-layered stratified media

Directory of Open Access Journals (Sweden)

D. Llanwyn Jones

1997-04-01

Full Text Available Formulas for computing the Cartesian components of the static (DC fields of horizontal electric dipoles ( HEDs and vertical electric dipoles ( VEDs located in the central zone of a three-layer horizontally stratified medium are derived and presented in a summary form suitable for immediate computation. Formulas are given for the electric and magnetic field components in the upper and central regions. In the general case the computation involves the summation of a convergent infinite series. For the particular case of an infinitely thick central region (corresponding to the two-layer problem, the analysis produces relatively simple closed-form equations for the field components which are suitable for a 'hand calculation'. Specimen calculations for dipoles in seawaters are included and the derived results are compared with computations made using an ac model.

Simulation model of stratified thermal energy storage tank using finite difference method

Science.gov (United States)

Waluyo, Joko

2016-06-01

Stratified TES tank is normally used in the cogeneration plant. The stratified TES tanks are simple, low cost, and equal or superior in thermal performance. The advantage of TES tank is that it enables shifting of energy usage from off-peak demand for on-peak demand requirement. To increase energy utilization in a stratified TES tank, it is required to build a simulation model which capable to simulate the charging phenomenon in the stratified TES tank precisely. This paper is aimed to develop a novel model in addressing the aforementioned problem. The model incorporated chiller into the charging of stratified TES tank system in a closed system. The model was developed in one-dimensional type involve with heat transfer aspect. The model covers the main factors affect to degradation of temperature distribution namely conduction through the tank wall, conduction between cool and warm water, mixing effect on the initial flow of the charging as well as heat loss to surrounding. The simulation model is developed based on finite difference method utilizing buffer concept theory and solved in explicit method. Validation of the simulation model is carried out using observed data obtained from operating stratified TES tank in cogeneration plant. The temperature distribution of the model capable of representing S-curve pattern as well as simulating decreased charging temperature after reaching full condition. The coefficient of determination values between the observed data and model obtained higher than 0.88. Meaning that the model has capability in simulating the charging phenomenon in the stratified TES tank. The model is not only capable of generating temperature distribution but also can be enhanced for representing transient condition during the charging of stratified TES tank. This successful model can be addressed for solving the limitation temperature occurs in charging of the stratified TES tank with the absorption chiller. Further, the stratified TES tank can be

Free Falling in Stratified Fluids

Science.gov (United States)

Lam, Try; Vincent, Lionel; Kanso, Eva

2017-11-01

Leaves falling in air and discs falling in water are examples of unsteady descents due to complex interaction between gravitational and aerodynamic forces. Understanding these descent modes is relevant to many branches of engineering and science such as estimating the behavior of re-entry space vehicles to studying biomechanics of seed dispersion. For regularly shaped objects falling in homogenous fluids, the motion is relatively well understood. However, less is known about how density stratification of the fluid medium affects the falling behavior. Here, we experimentally investigate the descent of discs in both pure water and in stable linearly stratified fluids for Froude numbers Fr 1 and Reynolds numbers Re between 1000 -2000. We found that stable stratification (1) enhances the radial dispersion of the disc at landing, (2) increases the descent time, (3) decreases the inclination (or nutation) angle, and (4) decreases the fluttering amplitude while falling. We conclude by commenting on how the corresponding information can be used as a predictive model for objects free falling in stratified fluids.

Approaches to large scale unsaturated flow in heterogeneous, stratified, and fractured geologic media

International Nuclear Information System (INIS)

Ababou, R.

1991-08-01

This report develops a broad review and assessment of quantitative modeling approaches and data requirements for large-scale subsurface flow in radioactive waste geologic repository. The data review includes discussions of controlled field experiments, existing contamination sites, and site-specific hydrogeologic conditions at Yucca Mountain. Local-scale constitutive models for the unsaturated hydrodynamic properties of geologic media are analyzed, with particular emphasis on the effect of structural characteristics of the medium. The report further reviews and analyzes large-scale hydrogeologic spatial variability from aquifer data, unsaturated soil data, and fracture network data gathered from the literature. Finally, various modeling strategies toward large-scale flow simulations are assessed, including direct high-resolution simulation, and coarse-scale simulation based on auxiliary hydrodynamic models such as single equivalent continuum and dual-porosity continuum. The roles of anisotropy, fracturing, and broad-band spatial variability are emphasized. 252 refs

The Amount of Media and Information Literacy Among Isfahan University of Medical Sciences' Students Using Iranian Media and Information Literacy Questionnaire (IMILQ).

Science.gov (United States)

Ashrafi-Rizi, Hasan; Ramezani, Amir; Koupaei, Hamed Aghajani; Kazempour, Zahra

2014-12-01

Media and Information literacy (MIL) enables people to interpret and make informed judgments as users of information and media, as well as to become skillful creators and producers of information and media messages in their own right. The purpose of this research was to determine the amount of Media and Information Literacy among Isfahan University of Medical Sciences' students using Iranian Media and Information Literacy Questionnaire (IMILQ). This is an applied analytical survey research in which the data were collected by a researcher made questionnaire, provided based on specialists' viewpoints and valid scientific works. Its validity and reliability were confirmed by Library and Information Sciences specialists and Cronbach's alpha (r=0.89) respectively. Statistical population consisted of all students in Isfahan University of Medical Sciences (6000 cases) and the samples were 361. Sampling method was random stratified sampling. Data were analyzed by descriptive and inferential statistics. The findings showed that the mean level of Media and Information Literacy among Isfahan University of Medical Sciences' students was 3.34±0.444 (higher than average). The highest mean was promotion of scientific degree with 3.84±0.975 and the lowest mean was difficulties in starting research with 2.50±1.08. There was significant difference between educational degree, college type and family's income and amount of Media and Information Literacy. The results showed that the students didn't have enough skills in starting the research, defining the research subject as well as confining the research subject. In general, all students and education practitioners should pay special attention to factors affecting in improving Media and Information Literacy as a main capability in using printed and electronic media.

Evaluation of the Impact of Media Marketing Strategies on Continuing Education Enrollments. AIR Forum 1982 Paper.

Science.gov (United States)

Campbell, Jill F.; Spiro, Louis M.

The impact of media marketing strategies on continuing education enrollment at the State University of New York College at Brockport (SUNY-CB), was evaluated. The evaluation of advertising impacts used advertising records of SUNY-CB and other area colleges and a telephone questionnaire instrument. A stratified, random countywide sample, in…

The DC field components of horizontal and vertical electric dipole sources immersed in three-layered stratified media

Directory of Open Access Journals (Sweden)

D. Llanwyn Jones

Full Text Available Formulas for computing the Cartesian components of the static (DC fields of horizontal electric dipoles ( HEDs and vertical electric dipoles ( VEDs located in the central zone of a three-layer horizontally stratified medium are derived and presented in a summary form suitable for immediate computation. Formulas are given for the electric and magnetic field components in the upper and central regions. In the general case the computation involves the summation of a convergent infinite series. For the particular case of an infinitely thick central region (corresponding to the two-layer problem, the analysis produces relatively simple closed-form equations for the field components which are suitable for a 'hand calculation'. Specimen calculations for dipoles in seawaters are included and the derived results are compared with computations made using an ac model.

Thermal stratification built up in hot water tank with different inlet stratifiers

DEFF Research Database (Denmark)

Dragsted, Janne; Furbo, Simon; Dannemand, Mark

2017-01-01

Thermal stratification in a water storage tank can strongly increase the thermal performance of solar heating systems. Thermal stratification can be built up in a storage tank during charge, if the heated water enters through an inlet stratifier. Experiments with a test tank have been carried out...... in order to elucidate how well thermal stratification is established in the tank with differently designed inlet stratifiers under different controlled laboratory conditions. The investigated inlet stratifiers are from Solvis GmbH & Co KG and EyeCular Technologies ApS. The inlet stratifier from Solvis Gmb...... for Solvis GmbH & Co KG had a better performance at 4 l/min. In the intermediate charge test the stratifier from EyeCular Technologies ApS had a better performance in terms of maintaining the thermal stratification in the storage tank while charging with a relative low temperature. [All rights reserved...

Large eddy simulation of turbulent and stably-stratified flows

International Nuclear Information System (INIS)

Fallon, Benoit

1994-01-01

The unsteady turbulent flow over a backward-facing step is studied by mean of Large Eddy Simulations with structure function sub grid model, both in isothermal and stably-stratified configurations. Without stratification, the flow develops highly-distorted Kelvin-Helmholtz billows, undergoing to helical pairing, with A-shaped vortices shed downstream. We show that forcing injected by recirculation fluctuations governs this oblique mode instabilities development. The statistical results show good agreements with the experimental measurements. For stably-stratified configurations, the flow remains more bi-dimensional. We show with increasing stratification, how the shear layer growth is frozen by inhibition of pairing process then of Kelvin-Helmholtz instabilities, and the development of gravity waves or stable density interfaces. Eddy structures of the flow present striking analogies with the stratified mixing layer. Additional computations show the development of secondary Kelvin-Helmholtz instabilities on the vorticity layers between two primary structures. This important mechanism based on baroclinic effects (horizontal density gradients) constitutes an additional part of the turbulent mixing process. Finally, the feasibility of Large Eddy Simulation is demonstrated for industrial flows, by studying a complex stratified cavity. Temperature fluctuations are compared to experimental measurements. We also develop three-dimensional un-stationary animations, in order to understand and visualize turbulent interactions. (author) [fr

Social media's and online user-generated content's role in services advertising

Science.gov (United States)

Stavrianea, A.; Kavoura, Androniki

2015-02-01

The aim of this paper is to present results from a study that examines the use of the Internet for collecting material and the attention people pay to advertisements through different media sources in the context of services. A representative stratified sample of 301 respondents of foreign arrivals of tourists in the Athens airport, Greece, collected in June and July 2014 was employed. We present which social media sources and user-generated material that promote advertisements were found to be important in capturing people's attention. Results illustrated the significant role that advertisements on Facebook play on the way people pay attention to. In fact, Facebook was found to be the second most important medium that people use when collecting material. In addition, Facebook was found to be the third source that respondents strongly agreed that they pay attention to advertisements, with the official websites/blogs to be the first source and travel guidebooks and travel magazines to follow, leaving traditional media far behind. Implications and suggestions are provided for online communication programs that may incorporate social media in services marketing communications campaigns. Libraries and corporate bodies may employ social media for advertising their services based on the significant role social media have.

Stratified Medicine and Reimbursement Issues

Directory of Open Access Journals (Sweden)

Hans-Joerg eFugel

2012-10-01

Full Text Available Stratified Medicine (SM has the potential to target patient populations who will most benefit from a therapy while reducing unnecessary health interventions associated with side effects. The link between clinical biomarkers/diagnostics and therapies provides new opportunities for value creation to strengthen the value proposition to pricing and reimbursement (P&R authorities. However, the introduction of SM challenges current reimbursement schemes in many EU countries and the US as different P&R policies have been adopted for drugs and diagnostics. Also, there is a lack of a consistent process for value assessment of more complex diagnostics in these markets. New, innovative approaches and more flexible P&R systems are needed to reflect the added value of diagnostic tests and to stimulate investments in new technologies. Yet, the framework for access of diagnostic–based therapies still requires further development while setting the right incentives and appropriate align stakeholders interests when realizing long- term patient benefits. This article addresses the reimbursement challenges of SM approaches in several EU countries and the US outlining some options to overcome existing reimbursement barriers for stratified medicine.

Numerical simulation of stratified flows with different k-ε turbulence models

International Nuclear Information System (INIS)

Dagestad, S.

1991-01-01

The thesis comprises the numerical simulation of stratified flows with different k-ε models. When using the k-ε model, two equations are solved to describe the turbulence. The k-equation represents the turbulent kinetic energy of the turbulence and the ε-equation is the turbulent dissipation. Different k-ε models predict stratified flows differently. The standard k-ε model leads to higher turbulent mixing than the low-Reynolds model does. For lower Froude numbers, F 0 , this effect becomes enhanced. Buoyancy extension of the k-ε model also leads to less vertical mixing in cases with strong stratification. When the stratification increases, buoyancy-extension becomes larger influence. The turbulent Prandtl number effects have large impact on the transport of heat and the development of the flow. Two different formulae which express the turbulent Prandtl effects have been tested. For unstably stratified flows, the rapid mixing and three-dimensionality of the flow can in fact be computed using a k-ε model when buoyancy-extended is employed. The turbulent heat transfer and thus turbulent production in unstable stratified flows depends strongly upon the turbulent Prandtl number effect. The main conclusions are: Stable stratified flows should be computed with a buoyancy-extended low-Reynolds k-ε model; Unstable stratified flows should be computed with a buoyancy-extended standard k-ε model; The turbulent Prandtl number effects should be included in the computations; Buoyancy-extension has lead to more correct description of the physics for all of the investigated flows. 78 refs., 128 figs., 17 tabs

MC3D modelling of stratified explosion

International Nuclear Information System (INIS)

Picchi, S.; Berthoud, G.

1999-01-01

It is known that a steam explosion can occur in a stratified geometry and that the observed yields are lower than in the case of explosion in a premixture configuration. However, very few models are available to quantify the amount of melt which can be involved and the pressure peak that can be developed. In the stratified application of the MC3D code, mixing and fragmentation of the melt are explained by the growth of Kelvin Helmholtz instabilities due to the shear flow of the two phase coolant above the melt. Such a model is then used to recalculate the Frost-Ciccarelli tin-water experiment. Pressure peak, speed of propagation, bubble shape and erosion height are well reproduced as well as the influence of the inertial constraint (height of the water pool). (author)

MC3D modelling of stratified explosion

Energy Technology Data Exchange (ETDEWEB)

Picchi, S.; Berthoud, G. [DTP/SMTH/LM2, CEA, 38 - Grenoble (France)

1999-07-01

It is known that a steam explosion can occur in a stratified geometry and that the observed yields are lower than in the case of explosion in a premixture configuration. However, very few models are available to quantify the amount of melt which can be involved and the pressure peak that can be developed. In the stratified application of the MC3D code, mixing and fragmentation of the melt are explained by the growth of Kelvin Helmholtz instabilities due to the shear flow of the two phase coolant above the melt. Such a model is then used to recalculate the Frost-Ciccarelli tin-water experiment. Pressure peak, speed of propagation, bubble shape and erosion height are well reproduced as well as the influence of the inertial constraint (height of the water pool). (author)

The effect of existing turbulence on stratified shear instability

Science.gov (United States)

Kaminski, Alexis; Smyth, William

2017-11-01

Ocean turbulence is an essential process governing, for example, heat uptake by the ocean. In the stably-stratified ocean interior, this turbulence occurs in discrete events driven by vertical variations of the horizontal velocity. Typically, these events have been modelled by assuming an initially laminar stratified shear flow which develops wavelike instabilities, becomes fully turbulent, and then relaminarizes into a stable state. However, in the real ocean there is always some level of turbulence left over from previous events, and it is not yet understood how this turbulence impacts the evolution of future mixing events. Here, we perform a series of direct numerical simulations of turbulent events developing in stratified shear flows that are already at least weakly turbulent. We do so by varying the amplitude of the initial perturbations, and examine the subsequent development of the instability and the impact on the resulting turbulent fluxes. This work is supported by NSF Grant OCE1537173.

Stratified source-sampling techniques for Monte Carlo eigenvalue analysis

International Nuclear Information System (INIS)

Mohamed, A.

1998-01-01

In 1995, at a conference on criticality safety, a special session was devoted to the Monte Carlo ''Eigenvalue of the World'' problem. Argonne presented a paper, at that session, in which the anomalies originally observed in that problem were reproduced in a much simplified model-problem configuration, and removed by a version of stratified source-sampling. In this paper, stratified source-sampling techniques are generalized and applied to three different Eigenvalue of the World configurations which take into account real-world statistical noise sources not included in the model problem, but which differ in the amount of neutronic coupling among the constituents of each configuration. It is concluded that, in Monte Carlo eigenvalue analysis of loosely-coupled arrays, the use of stratified source-sampling reduces the probability of encountering an anomalous result over that if conventional source-sampling methods are used. However, this gain in reliability is substantially less than that observed in the model-problem results

Visualization of mole fraction distribution of slow jet forming stably stratified field

International Nuclear Information System (INIS)

Fumizawa, Motoo; Hishida, Makoto

1990-01-01

An experimental study has been performed to investigate the behavior of flow and mass transfer in gaseous slow jet in which buoyancy force opposed the flow forming stably stratified field. The study has been performed to understand the basic features of air ingress phenomena at pipe rupture accident of the high temperature gas-cooled reactor. A displacement fringe technique was adopted in Mach-Zehnder interferometer to visualize the mole fraction distribution. As the result, the followings were obtained: (1) The stably stratified fields were formed in the vicinity of the outlet of the slow jet. The penetration distance of the stably stratified fields increased with Froude number. (2) Mass fraction distributions in the stably stratified fields were well correlated with the present model using the ramp mole velocity profile. (author)

Simulation of steam explosion in stratified melt-coolant configuration

International Nuclear Information System (INIS)

Leskovar, Matjaž; Centrih, Vasilij; Uršič, Mitja

2016-01-01

Highlights: • Strong steam explosions may develop spontaneously in stratified configurations. • Considerable melt-coolant premixed layer formed in subcooled water with hot melts. • Analysis with MC3D code provided insight into stratified steam explosion phenomenon. • Up to 25% of poured melt was mixed with water and available for steam explosion. • Better instrumented experiments needed to determine dominant mixing process. - Abstract: A steam explosion is an energetic fuel coolant interaction process, which may occur during a severe reactor accident when the molten core comes into contact with the coolant water. In nuclear reactor safety analyses steam explosions are primarily considered in melt jet-coolant pool configurations where sufficiently deep coolant pool conditions provide complete jet breakup and efficient premixture formation. Stratified melt-coolant configurations, i.e. a molten melt layer below a coolant layer, were up to now believed as being unable to generate strong explosive interactions. Based on the hypothesis that there are no interfacial instabilities in a stratified configuration it was assumed that the amount of melt in the premixture is insufficient to produce strong explosions. However, the recently performed experiments in the PULiMS and SES (KTH, Sweden) facilities with oxidic corium simulants revealed that strong steam explosions may develop spontaneously also in stratified melt-coolant configurations, where with high temperature melts and subcooled water conditions a considerable melt-coolant premixed layer is formed. In the article, the performed study of steam explosions in a stratified melt-coolant configuration in PULiMS like conditions is presented. The goal of this analytical work is to supplement the experimental activities within the PULiMS research program by addressing the key questions, especially regarding the explosivity of the formed premixed layer and the mechanisms responsible for the melt-water mixing. To

RADIAL STABILITY IN STRATIFIED STARS

International Nuclear Information System (INIS)

Pereira, Jonas P.; Rueda, Jorge A.

2015-01-01

We formulate within a generalized distributional approach the treatment of the stability against radial perturbations for both neutral and charged stratified stars in Newtonian and Einstein's gravity. We obtain from this approach the boundary conditions connecting any two phases within a star and underline its relevance for realistic models of compact stars with phase transitions, owing to the modification of the star's set of eigenmodes with respect to the continuous case

Soil mixing of stratified contaminated sands.

Science.gov (United States)

Al-Tabba, A; Ayotamuno, M J; Martin, R J

2000-02-01

Validation of soil mixing for the treatment of contaminated ground is needed in a wide range of site conditions to widen the application of the technology and to understand the mechanisms involved. Since very limited work has been carried out in heterogeneous ground conditions, this paper investigates the effectiveness of soil mixing in stratified sands using laboratory-scale augers. This enabled a low cost investigation of factors such as grout type and form, auger design, installation procedure, mixing mode, curing period, thickness of soil layers and natural moisture content on the unconfined compressive strength, leachability and leachate pH of the soil-grout mixes. The results showed that the auger design plays a very important part in the mixing process in heterogeneous sands. The variability of the properties measured in the stratified soils and the measurable variations caused by the various factors considered, highlighted the importance of duplicating appropriate in situ conditions, the usefulness of laboratory-scale modelling of in situ conditions and the importance of modelling soil and contaminant heterogeneities at the treatability study stage.

Stratified charge rotary aircraft engine technology enablement program

Science.gov (United States)

Badgley, P. R.; Irion, C. E.; Myers, D. M.

1985-01-01

The multifuel stratified charge rotary engine is discussed. A single rotor, 0.7L/40 cu in displacement, research rig engine was tested. The research rig engine was designed for operation at high speeds and pressures, combustion chamber peak pressure providing margin for speed and load excursions above the design requirement for a high is advanced aircraft engine. It is indicated that the single rotor research rig engine is capable of meeting the established design requirements of 120 kW, 8,000 RPM, 1,379 KPA BMEP. The research rig engine, when fully developed, will be a valuable tool for investigating, advanced and highly advanced technology components, and provide an understanding of the stratified charge rotary engine combustion process.

General Practitioners Views of Implementing a Stratified Treatment Approach for Low Back Pain in Germany: A Qualitative Study.

Directory of Open Access Journals (Sweden)

Sven Karstens

Full Text Available The STarT Back stratified primary care approach has demonstrated clinical and cost effectiveness in the UK, and is commonly used by General Practitioners (GPs. However, it remains unknown how this approach could be implemented into the German healthcare system. The aim of this study was therefore to explore the views and perceptions of German GPs in respect to using a stratified primary care for low back pain (LBP.A 90-minute think-tank workshop was conducted with 14 male and five female GPs, during which the STarT-Back-Screening-Tool (SBST and related research evidence was presented. This was followed by two focus groups, based on a semi-structured interview guideline to identify potential implementation barriers and opportunities. Discussions were audiotaped, transcribed and coded using a content analysis approach.For the three deductively developed main themes, 15 subthemes emerged: (1 application of the SBST, with the following subthemes: which health profession should administer it, patients known to the GP practice, the reason for the GP consultation, scoring the tool, the tool format, and the anticipated impact on GP practice; (2 psychologically informed physiotherapy, with subthemes including: provision by a physiotherapist, anticipated impact, the skills of physiotherapists, management of patients with severe psychosocial problems, referral and remuneration; (3 the management of low-risk patients, with subthemes including: concern about the appropriate advising health professional, information and media, length of consultation, and local exercise venues.The attitudes of GPs towards stratified primary care for LBP indicated positive support for pilot-testing in Germany. However, there were mixed reactions to the ability of German physiotherapists to manage high-risk patients and handle their complex clinical needs. GPs also mentioned practical difficulties in providing extended advice to low-risk patients, which nevertheless could be

A review of recent developments on turbulent entrainment in stratified flows

International Nuclear Information System (INIS)

Cotel, Aline J

2010-01-01

Stratified interfaces are present in many geophysical flow situations, and transport across such an interface is an essential factor for correctly evaluating the physical processes taking place at many spatial and temporal scales in such flows. In order to accurately evaluate vertical and lateral transport occurring when a turbulent flow impinges on a stratified interface, the turbulent entrainment and vorticity generation mechanisms near the interface must be understood and quantified. Laboratory experiments were performed for three flow configurations: a vertical thermal, a sloping gravity current and a vertical turbulent jet with various tilt angles and precession speeds. All three flows impinged on an interface separating a two-layer stably stratified environment. The entrainment rate is quantified for each flow using laser-induced fluorescence and compared to predictions of Cotel and Breidenthal (1997 Appl. Sci. Res. 57 349-66). The possible applications of transport across stratified interfaces include the contribution of hydrothermal plumes to the global ocean energy budget, turbidity currents on the ocean floor, the design of lake de-stratification systems, modeling gas leaks from storage reservoirs, weather forecasting and global climate change.

Stratified turbulent Bunsen flames : flame surface analysis and flame surface density modelling

NARCIS (Netherlands)

Ramaekers, W.J.S.; Oijen, van J.A.; Goey, de L.P.H.

2012-01-01

In this paper it is investigated whether the Flame Surface Density (FSD) model, developed for turbulent premixed combustion, is also applicable to stratified flames. Direct Numerical Simulations (DNS) of turbulent stratified Bunsen flames have been carried out, using the Flamelet Generated Manifold

Two-phase air-water stratified flow measurement using ultrasonic techniques

International Nuclear Information System (INIS)

Fan, Shiwei; Yan, Tinghu; Yeung, Hoi

2014-01-01

In this paper, a time resolved ultrasound system was developed for investigating two-phase air-water stratified flow. The hardware of the system includes a pulsed wave transducer, a pulser/receiver, and a digital oscilloscope. The time domain cross correlation method is used to calculate the velocity profile along ultrasonic beam. The system is able to provide velocities with spatial resolution of around 1mm and the temporal resolution of 200μs. Experiments were carried out on single phase water flow and two-phase air-water stratified flow. For single phase water flow, the flow rates from ultrasound system were compared with those from electromagnetic flow (EM) meter, which showed good agreement. Then, the experiments were conducted on two-phase air-water stratified flow and the results were given. Compared with liquid height measurement from conductance probe, it indicated that the measured velocities were explainable

Simulations of Gamma-Ray Burst Jets in a Stratified External Medium: Dynamics, Afterglow Light Curves, Jet Breaks, and Radio Calorimetry

Science.gov (United States)

De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

2012-05-01

The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρextvpropr -k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ-1 0. For larger k values, however, the lateral expansion is faster at early times (when Γ > θ-1 0) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θobs <= θ0) than by the slope of the external density profile (for 0 <= k <= 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet decelerates more

Spinning phenomena and energetics of spherically pulsating patterns in stratified fluids

International Nuclear Information System (INIS)

Ibragimov, Ranis N; Dameron, Michael

2011-01-01

The nonlinear solutions of the two-dimensional Boussinesq equations describing internal waves in rotating stratified fluids were obtained as group invariant solutions. The latter nonlinear solutions correspond to the rotation transformation preserving the form of the original nonlinear equations of motion. It is shown that the obtained class of exact solutions can be associated with the spherically pulsating patterns observed in uniformly stratified fluids. It is also shown that the obtained rotationally symmetric solutions are bounded functions that can be visualized as spinning patterns in stratified fluids. It is also shown that the rotational transformation provides the energy conservation law together with other conservation laws for which the spinning phenomena is observed. The effects of nonlinearity and the Earth's rotation on such a phenomenon are also discussed.

Modeling the Conducting Stably-Stratified Layer of the Earth's Core

Science.gov (United States)

Petitdemange, L.; Philidet, J.; Gissinger, C.

2017-12-01

Observations of the Earth magnetic field as well as recent theoretical works tend to show that the Earth's outer liquid core is mostly comprised of a convective zone in which the Earth's magnetic field is generated - likely by dynamo action -, but also features a thin, stably stratified layer at the top of the core.We carry out direct numerical simulations by modeling this thin layer as an axisymmetric spherical Couette flow for a stably stratified fluid embedded in a dipolar magnetic field. The dynamo region is modeled by a conducting inner core rotating slightly faster than the insulating mantle due to magnetic torques acting on it, such that a weak differential rotation (low Rossby limit) can develop in the stably stratified layer.In the case of a non-stratified fluid, the combined action of the differential rotation and the magnetic field leads to the well known regime of `super-rotation', in which the fluid rotates faster than the inner core. Whereas in the classical case, this super-rotation is known to vanish in the magnetostrophic limit, we show here that the fluid stratification significantly extends the magnitude of the super-rotation, keeping this phenomenon relevant for the Earth core. Finally, we study how the shear layers generated by this new state might give birth to magnetohydrodynamic instabilities or waves impacting the secular variations or jerks of the Earth's magnetic field.

VLA and low-frequency VLBI observations of the radio source 0503 + 467 - Austere constraints on interstellar scattering in two media

International Nuclear Information System (INIS)

Spangler, S.R.; Fey, A.L.; Cordes, J.M.; Cornell Univ., Ithaca, NY)

1987-01-01

The radio source 0503 + 467 lies near the Galactic plane (l = 161.0 deg, b = 3.7 deg) and at the edge of the supernova remnant (SNR) HB 9. The VLA observations show that it has a spectrum typical of a compact extragalactic radio source. The resultant small angular size of the source makes it an excellent probe of turbulence in two media: the diffuse, or type A, component of interstellar turbulence and a hypothesized region of hydromagnetic turbulence upstream of the supernova remnant. An eight-station VLBI experiment at 326 MHz indicates that the source is less than about 20 milliarcseconds (mas) in angular diameter. A value of 16 mas is most appropriate as an upper limit to the interstellar scattering contribution to the measured angular size. The implications of this upper limit are twofold. First, the galactocentric radial scale to the type-A turbulence is probably less than or equal to about 6 kpc. Second, no evidence is seen for shock-associated turbulence upstream of HB 9. The measurements make it possible to constrain a parameter which is a function of the rms density fluctuation in the upstream region, the outer scale to the density turbulence, and the thickness of SNR foreshock region. 14 references

Background stratified Poisson regression analysis of cohort data.

Science.gov (United States)

Richardson, David B; Langholz, Bryan

2012-03-01

Background stratified Poisson regression is an approach that has been used in the analysis of data derived from a variety of epidemiologically important studies of radiation-exposed populations, including uranium miners, nuclear industry workers, and atomic bomb survivors. We describe a novel approach to fit Poisson regression models that adjust for a set of covariates through background stratification while directly estimating the radiation-disease association of primary interest. The approach makes use of an expression for the Poisson likelihood that treats the coefficients for stratum-specific indicator variables as 'nuisance' variables and avoids the need to explicitly estimate the coefficients for these stratum-specific parameters. Log-linear models, as well as other general relative rate models, are accommodated. This approach is illustrated using data from the Life Span Study of Japanese atomic bomb survivors and data from a study of underground uranium miners. The point estimate and confidence interval obtained from this 'conditional' regression approach are identical to the values obtained using unconditional Poisson regression with model terms for each background stratum. Moreover, it is shown that the proposed approach allows estimation of background stratified Poisson regression models of non-standard form, such as models that parameterize latency effects, as well as regression models in which the number of strata is large, thereby overcoming the limitations of previously available statistical software for fitting background stratified Poisson regression models.

Nitrogen transformations in stratified aquatic microbial ecosystems

DEFF Research Database (Denmark)

Revsbech, N. P.; Risgaard-Petersen, N.; Schramm, A.

2006-01-01

Abstract  New analytical methods such as advanced molecular techniques and microsensors have resulted in new insights about how nitrogen transformations in stratified microbial systems such as sediments and biofilms are regulated at a µm-mm scale. A large and ever-expanding knowledge base about n...

[Causes of emergency dizziness stratified by etiology].

Science.gov (United States)

Qiao, Wenying; Liu, Jianguo; Zeng, Hong; Liu, Yugeng; Jia, Weihua; Wang, Honghong; Liu, Bo; Tan, Jing; Li, Changqing

2014-06-03

To explore the causes of emergency dizziness stratified to improve the diagnostic efficiency. A total of 1 857 cases of dizziness at our emergency department were collected and their etiologies stratified by age and gender. The top three diagnoses were benign paroxysmal positional vertigo (BPPV, 31.7%), hypertension (24.0%) and posterior circulation ischemia (PCI, 20.5%). Stratified by age, the main causes of dizziness included BPPV (n = 6), migraine-associated vertigo (n = 2), unknown cause (n = 1) for the group of vertigo (14.5%) and neurosis (7.3%) for 18-44 years; BPPV (36.8%), hypertension (22.4%) and migraine-associated vertigo (11.2%) for 45-59 years; hypertension (30.8%), PCI (29.8%) and BPPV (22.9%) for 60-74 years; PCI (30.7%), hypertension (28.6%) and BPPV (25.5%) for 75-92 years. BPPV, migraine and neurosis were more common in females while hypertension and PCI predominated in males (all P hypertension, neurosis and migraine showed the following significant demographic features: BPPV, PCI, hypertension, neurosis and migraine may be the main causes of dizziness. BPPV should be considered initially when vertigo was triggered repeatedly by positional change, especially for young and middle-aged women. And the other common causes of dizziness were migraine-associated vertigo, neurosis and Meniere's disease.Hypertension should be screened firstly in middle-aged and elderly patients presenting mainly with head heaviness and stretching. In elders with dizziness, BPPV is second in constituent ratio to PCI and hypertension.In middle-aged and elderly patients with dizziness, psychological factors should be considered and diagnosis and treatment should be offered timely.

Hydromagnetic slip flow of water based nano-fluids past a wedge with convective surface in the presence of heat generation (or) absorption

International Nuclear Information System (INIS)

Rahman, M.M.; Al-Lawatia, M.A.; Eltayeb, I.A.; Al-Salti, N.

2012-01-01

Heat transfer characteristics of a two-dimensional steady hydromagnetic slip flow of water based nano-fluids (TiO 2 -water, Al 2 O 3 -water, and Cu-water) over a wedge with convective surface taking into account the effects of heat generation (or absorption) has been investigated numerically. The local similarity solutions are obtained by using very robust computer algebra software MATLAB and presented graphically as well as in a tabular form. The results show that nano-fluid velocity is lower than the velocity of the base fluid and the existence of the nano-fluid leads to the thinning of the hydrodynamic boundary layer. The rate of shear stress is significantly influenced by the surface convection parameter and the slip parameter. It is higher for nano-fluids than the base fluid. The results also show that within the boundary layer the temperature of the nano-fluid is higher than the temperature of the base fluid. The rate of heat transfer is found to increase with the increase of the surface convection and the slip parameters. Addition of nano-particles to the base fluid induces the rate of heat transfer. The rate of heat transfer in the Cu-water nano-fluid is found to be higher than the rate of heat transfer in the TiO 2 -water and Al 2 O 3 -water nano-fluids. (authors)

Molecular polymorphism of a cell surface proteoglycan: distinct structures on simple and stratified epithelia.

Science.gov (United States)

Sanderson, R D; Bernfield, M

1988-12-01

Epithelial cells are organized into either a single layer (simple epithelia) or multiple layers (stratified epithelia). Maintenance of these cellular organizations requires distinct adhesive mechanisms involving many cell surface molecules. One such molecule is a cell surface proteoglycan, named syndecan, that contains both heparan sulfate and chondroitin sulfate chains. This proteoglycan binds cells to fibrillar collagens and fibronectin and thus acts as a receptor for interstitial matrix. The proteoglycan is restricted to the basolateral surface of simple epithelial cells, but is located over the entire surface of stratified epithelial cells, even those surfaces not contacting matrix. We now show that the distinct localization in simple and stratified epithelia correlates with a distinct proteoglycan structure. The proteoglycan from simple epithelia (modal molecular size, 160 kDa) is larger than that from stratified epithelia (modal molecular size, 92 kDa), but their core proteins are identical in size and immunoreactivity. The proteoglycan from simple epithelia has more and larger heparan sulfate and chondroitin sulfate chains than the proteoglycan from stratified epithelia. Thus, the cell surface proteoglycan shows a tissue-specific structural polymorphism due to distinct posttranslational modifications. This polymorphism likely reflects distinct proteoglycan functions in simple and stratified epithelia, potentially meeting the different adhesive requirements of the cells in these different organizations.

Mass media effect on vaccines uptake during silent polio outbreak.

Science.gov (United States)

Sagy, Iftach; Novack, Victor; Gdalevich, Michael; Greenberg, Dan

2018-03-14

During 2013, isolation of a wild type 1 poliovirus from routine sewage sample in Israel, led to a national OPV campaign. During this period, there was a constant cover of the outbreak by the mass media. To investigate the association of media exposure and OPV and non-OPV vaccines uptake during the 2013 silent polio outbreak in Israel. We received data on daily immunization rates during the outbreak period from the Ministry of Health (MoH). We conducted a multivariable time trend analysis to assess the association between daily media exposure and vaccines uptake. Analysis was stratified by ethnicity and socio-economic status (SES). During the MoH supplemental immunization activity, 138,799 OPV vaccines were given. There was a significant association between media exposure and OPV uptake, most prominent in a lag of 3-5 days from the exposure among Jews (R.R 1.79C.I 95% 1.32-2.41) and high SES subgroups (R.R 1.71C.I 95% 1.27-2.30). These subgroups also showed increased non-OPV uptake in a lag of 3-5 days from the media exposure, in all vaccines except for MMR. Lower SES and non-Jewish subgroups did not demonstrate the same association. Our findings expand the understanding of public behaviour during outbreaks. The public response shows high variability within specific subgroups. These findings highlight the importance of tailored communication strategies for each subgroup. Copyright © 2018 Elsevier Ltd. All rights reserved.

Background stratified Poisson regression analysis of cohort data

International Nuclear Information System (INIS)

Richardson, David B.; Langholz, Bryan

2012-01-01

Background stratified Poisson regression is an approach that has been used in the analysis of data derived from a variety of epidemiologically important studies of radiation-exposed populations, including uranium miners, nuclear industry workers, and atomic bomb survivors. We describe a novel approach to fit Poisson regression models that adjust for a set of covariates through background stratification while directly estimating the radiation-disease association of primary interest. The approach makes use of an expression for the Poisson likelihood that treats the coefficients for stratum-specific indicator variables as 'nuisance' variables and avoids the need to explicitly estimate the coefficients for these stratum-specific parameters. Log-linear models, as well as other general relative rate models, are accommodated. This approach is illustrated using data from the Life Span Study of Japanese atomic bomb survivors and data from a study of underground uranium miners. The point estimate and confidence interval obtained from this 'conditional' regression approach are identical to the values obtained using unconditional Poisson regression with model terms for each background stratum. Moreover, it is shown that the proposed approach allows estimation of background stratified Poisson regression models of non-standard form, such as models that parameterize latency effects, as well as regression models in which the number of strata is large, thereby overcoming the limitations of previously available statistical software for fitting background stratified Poisson regression models. (orig.)

Theoretical study of evaporation heat transfer in horizontal microfin tubes: stratified flow model

Energy Technology Data Exchange (ETDEWEB)

Honda, H; Wang, Y S [Kyushu Univ., Inst. for Materials Chemistry and Engineering, Kasuga, Fukuoka (Japan)

2004-08-01

The stratified flow model of evaporation heat transfer in helically grooved, horizontal microfin tubes has been developed. The profile of stratified liquid was determined by a theoretical model previously developed for condensation in horizontal microfin tubes. For the region above the stratified liquid, the meniscus profile in the groove between adjacent fins was determined by a force balance between the gravity and surface tension forces. The thin film evaporation model was applied to predict heat transfer in the thin film region of the meniscus. Heat transfer through the stratified liquid was estimated by using an empirical correlation proposed by Mori et al. The theoretical predictions of the circumferential average heat transfer coefficient were compared with available experimental data for four tubes and three refrigerants. A good agreement was obtained for the region of Fr{sub 0}<2.5 as long as partial dry out of tube surface did not occur. (Author)

Dual Spark Plugs For Stratified-Charge Rotary Engine

Science.gov (United States)

Abraham, John; Bracco, Frediano V.

1996-01-01

Fuel efficiency of stratified-charge, rotary, internal-combustion engine increased by improved design featuring dual spark plugs. Second spark plug ignites fuel on upstream side of main fuel injector; enabling faster burning and more nearly complete utilization of fuel.

Implementing content constraints in alpha-stratified adaptive testing using a shadow test approach

NARCIS (Netherlands)

van der Linden, Willem J.; Chang, Hua-Hua

2001-01-01

The methods of alpha-stratified adaptive testing and constrained adaptive testing with shadow tests are combined in this study. The advantages are twofold. First, application of the shadow test allows the researcher to implement any type of constraint on item selection in alpha-stratified adaptive

Stratified coastal ocean interactions with tropical cyclones

Science.gov (United States)

Glenn, S. M.; Miles, T. N.; Seroka, G. N.; Xu, Y.; Forney, R. K.; Yu, F.; Roarty, H.; Schofield, O.; Kohut, J.

2016-01-01

Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward. PMID:26953963

Properties of the endogenous post-stratified estimator using a random forests model

Science.gov (United States)

John Tipton; Jean Opsomer; Gretchen G. Moisen

2012-01-01

Post-stratification is used in survey statistics as a method to improve variance estimates. In traditional post-stratification methods, the variable on which the data is being stratified must be known at the population level. In many cases this is not possible, but it is possible to use a model to predict values using covariates, and then stratify on these predicted...

Sensitivity and inversion of full seismic waveforms in stratified porous medium; Sensibilite et inversion de formes d'ondes completes en milieu poreux stratifie

Energy Technology Data Exchange (ETDEWEB)

Barros, L. de

2007-12-15

Characterization of porous media parameters, and particularly the porosity, permeability and fluid properties are very useful in many applications (hydrologic, natural hazards or oil industry). The aim of my research is to evaluate the possibility to determine these properties from the full seismic wave fields. First, I am interested in the useful parameters and the specific properties of the seismic waves in the poro-elastic theory, often called Biot (1956) theory. I then compute seismic waves propagation in fluid saturated stratified porous media with a reflectivity method coupled with the discrete wavenumber integration method. I first used this modeling to study the possibilities to determine the carbon dioxide concentration and localization thanks to the reflected P-waves in the case of the deep geological storage of Sleipner (North Sea). The sensitivity of the seismic response to the poro-elastic parameters are then generalized by the analytical computation of the Frechet derivatives which are expressed in terms of the Green's functions of the unperturbed medium. The numerical tests show that the porosity and the consolidation are the main parameters to invert. The sensitivity operators are then introduced in a inversion algorithm based on iterative modeling of the full waveform. The classical algorithm of generalized least-square inverse problem is solved by the quasi-Newton technique (Tarantola, 1984). The inversion of synthetic data show that we can invert for the porosity and the fluid and solid parameters (densities and mechanical modulus, or volume rate of fluid and mineral) can be correctly rebuilt if the other parameters are well known. However, the strong seismic coupling of the porous parameters leads to difficulties to invert simultaneously for several parameters. One way to get round these difficulties is to use additional information and invert for one single parameter for the fluid properties (saturating rate) or for the lithology. An other

Study of MRI in stratified viscous plasma configuration

Science.gov (United States)

Carlevaro, Nakia; Montani, Giovanni; Renzi, Fabrizio

2017-02-01

We analyze the morphology of the magneto-rotational instability (MRI) for a stratified viscous plasma disk configuration in differential rotation, taking into account the so-called corotation theorem for the background profile. In order to select the intrinsic Alfvénic nature of MRI, we deal with an incompressible plasma and we adopt a formulation of the local perturbation analysis based on the use of the magnetic flux function as a dynamical variable. Our study outlines, as consequence of the corotation condition, a marked asymmetry of the MRI with respect to the equatorial plane, particularly evident in a complete damping of the instability over a positive critical height on the equatorial plane. We also emphasize how such a feature is already present (although less pronounced) even in the ideal case, restoring a dependence of the MRI on the stratified morphology of the gravitational field.

Solution of stochastic media transport problems using a numerical quadrature-based method

International Nuclear Information System (INIS)

Pautz, S. D.; Franke, B. C.; Prinja, A. K.; Olson, A. J.

2013-01-01

We present a new conceptual framework for analyzing transport problems in random media. We decompose such problems into stratified subproblems according to the number of material pseudo-interfaces within realizations. For a given subproblem we assign pseudo-interface locations in each realization according to product quadrature rules, which allows us to deterministically generate a fixed number of realizations. Quadrature integration of the solutions of these realizations thus approximately solves each subproblem; the weighted superposition of solutions of the subproblems approximately solves the general stochastic media transport problem. We revisit some benchmark problems to determine the accuracy and efficiency of this approach in comparison to randomly generated realizations. We find that this method is very accurate and fast when the number of pseudo-interfaces in a problem is generally low, but that these advantages quickly degrade as the number of pseudo-interfaces increases. (authors)

SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

International Nuclear Information System (INIS)

De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

2012-01-01

The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρ ext ∝r –k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ 0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ –1 0 . For larger k values, however, the lateral expansion is faster at early times (when Γ > θ –1 0 ) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θ obs ≤ θ 0 ) than by the slope of the external density profile (for 0 ≤ k ≤ 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet

SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

Energy Technology Data Exchange (ETDEWEB)

De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)

2012-05-20

The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with {rho}{sub ext}{proportional_to}r{sup -k} for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle {theta}{sub 0} = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor {Gamma} drops below {theta}{sup -1}{sub 0}. For larger k values, however, the lateral expansion is faster at early times (when {Gamma} > {theta}{sup -1}{sub 0}) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for {theta}{sub obs} {<=} {theta}{sub 0}) than by the slope of the external density profile (for 0 {<=} k {<=} 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results

On Internal Waves in a Density-Stratified Estuary

NARCIS (Netherlands)

Kranenburg, C.

1991-01-01

In this article some field observations, made in recent years, of internal wave motions in a density-stratified estuary are presented, In order to facilitate the appreciation of the results, and to make some quantitative comparisons, the relevant theory is also summarized. Furthermore, the origins

Prognosis research strategy (PROGRESS) 4: Stratified medicine research

NARCIS (Netherlands)

A. Hingorani (Aroon); D.A.W.M. van der Windt (Daniëlle); R.D. Riley (Richard); D. Abrams; K.G.M. Moons (Karel); E.W. Steyerberg (Ewout); S. Schroter (Sara); W. Sauerbrei (Willi); D.G. Altman (Douglas); H. Hemingway; A. Briggs (Andrew); N. Brunner; P. Croft (Peter); J. Hayden (Jill); P.A. Kyzas (Panayiotis); N. Malats (Núria); G. Peat; P. Perel (Pablo); I. Roberts (Ian); A. Timmis (Adam)

2013-01-01

textabstractIn patients with a particular disease or health condition, stratified medicine seeks to identify thosewho will have the most clinical benefit or least harm from a specific treatment. In this article, thefourth in the PROGRESS series, the authors discuss why prognosis research should form

Stratified Simulations of Collisionless Accretion Disks

Energy Technology Data Exchange (ETDEWEB)

Hirabayashi, Kota; Hoshino, Masahiro, E-mail: hirabayashi-k@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, Tokyo, 113-0033 (Japan)

2017-06-10

This paper presents a series of stratified-shearing-box simulations of collisionless accretion disks in the recently developed framework of kinetic magnetohydrodynamics (MHD), which can handle finite non-gyrotropy of a pressure tensor. Although a fully kinetic simulation predicted a more efficient angular-momentum transport in collisionless disks than in the standard MHD regime, the enhanced transport has not been observed in past kinetic-MHD approaches to gyrotropic pressure anisotropy. For the purpose of investigating this missing link between the fully kinetic and MHD treatments, this paper explores the role of non-gyrotropic pressure and makes the first attempt to incorporate certain collisionless effects into disk-scale, stratified disk simulations. When the timescale of gyrotropization was longer than, or comparable to, the disk-rotation frequency of the orbit, we found that the finite non-gyrotropy selectively remaining in the vicinity of current sheets contributes to suppressing magnetic reconnection in the shearing-box system. This leads to increases both in the saturated amplitude of the MHD turbulence driven by magnetorotational instabilities and in the resultant efficiency of angular-momentum transport. Our results seem to favor the fast advection of magnetic fields toward the rotation axis of a central object, which is required to launch an ultra-relativistic jet from a black hole accretion system in, for example, a magnetically arrested disk state.

Dispersion of (light) inertial particles in stratified turbulence

NARCIS (Netherlands)

van Aartrijk, M.; Clercx, H.J.H.; Armenio, Vincenzo; Geurts, Bernardus J.; Fröhlich, Jochen

2010-01-01

We present a brief overview of a numerical study of the dispersion of particles in stably stratified turbulence. Three types of particles arc examined: fluid particles, light inertial particles ($\\rho_p/\\rho_f = \\mathcal{O}(1)$) and heavy inertial particles ($\\rho_p/\\rho_f \\gg 1$). Stratification

Internal circle uplifts, transversality and stratified G-structures

Energy Technology Data Exchange (ETDEWEB)

Babalic, Elena Mirela [Department of Theoretical Physics, National Institute of Physics and Nuclear Engineering,Str. Reactorului no.30, P.O.BOX MG-6, Postcode 077125, Bucharest-Magurele (Romania); Department of Physics, University of Craiova,13 Al. I. Cuza Str., Craiova 200585 (Romania); Lazaroiu, Calin Iuliu [Center for Geometry and Physics, Institute for Basic Science,Pohang 790-784 (Korea, Republic of)

2015-11-24

We study stratified G-structures in N=2 compactifications of M-theory on eight-manifolds M using the uplift to the auxiliary nine-manifold M̂=M×S{sup 1}. We show that the cosmooth generalized distribution D̂ on M̂ which arises in this formalism may have pointwise transverse or non-transverse intersection with the pull-back of the tangent bundle of M, a fact which is responsible for the subtle relation between the spinor stabilizers arising on M and M̂ and for the complicated stratified G-structure on M which we uncovered in previous work. We give a direct explanation of the latter in terms of the former and relate explicitly the defining forms of the SU(2) structure which exists on the generic locus U of M to the defining forms of the SU(3) structure which exists on an open subset Û of M̂, thus providing a dictionary between the eight- and nine-dimensional formalisms.

Dyadic Green's function of an eccentrically stratified sphere.

Science.gov (United States)

Moneda, Angela P; Chrissoulidis, Dimitrios P

2014-03-01

The electric dyadic Green's function (dGf) of an eccentrically stratified sphere is built by use of the superposition principle, dyadic algebra, and the addition theorem of vector spherical harmonics. The end result of the analytical formulation is a set of linear equations for the unknown vector wave amplitudes of the dGf. The unknowns are calculated by truncation of the infinite sums and matrix inversion. The theory is exact, as no simplifying assumptions are required in any one of the analytical steps leading to the dGf, and it is general in the sense that any number, position, size, and electrical properties can be considered for the layers of the sphere. The point source can be placed outside of or in any lossless part of the sphere. Energy conservation, reciprocity, and other checks verify that the dGf is correct. A numerical application is made to a stratified sphere made of gold and glass, which operates as a lens.

Stratified B-trees and versioning dictionaries

OpenAIRE

Twigg, Andy; Byde, Andrew; Milos, Grzegorz; Moreton, Tim; Wilkes, John; Wilkie, Tom

2011-01-01

A classic versioned data structure in storage and computer science is the copy-on-write (CoW) B-tree -- it underlies many of today's file systems and databases, including WAFL, ZFS, Btrfs and more. Unfortunately, it doesn't inherit the B-tree's optimality properties; it has poor space utilization, cannot offer fast updates, and relies on random IO to scale. Yet, nothing better has been developed since. We describe the `stratified B-tree', which beats all known semi-external memory versioned B...

Analysis of photonic band-gap structures in stratified medium

DEFF Research Database (Denmark)

Tong, Ming-Sze; Yinchao, Chen; Lu, Yilong

2005-01-01

in electromagnetic and microwave applications once the Maxwell's equations are appropriately modeled. Originality/value - The method validates its values and properties through extensive studies on regular and defective 1D PBG structures in stratified medium, and it can be further extended to solving more......Purpose - To demonstrate the flexibility and advantages of a non-uniform pseudo-spectral time domain (nu-PSTD) method through studies of the wave propagation characteristics on photonic band-gap (PBG) structures in stratified medium Design/methodology/approach - A nu-PSTD method is proposed...... in solving the Maxwell's equations numerically. It expands the temporal derivatives using the finite differences, while it adopts the Fourier transform (FT) properties to expand the spatial derivatives in Maxwell's equations. In addition, the method makes use of the chain-rule property in calculus together...

The Values of Combined and Sub-Stratified Imaging Scores with Ultrasonography and Mammography in Breast Cancer Subtypes.

Directory of Open Access Journals (Sweden)

Tsun-Hou Chang

Full Text Available The Breast Imaging Reporting and Data System (BI-RADS of Mammography (MG and Ultrasonography (US were equivalent to the "5-point score" and applied for combined and sub-stratified imaging assessments. This study evaluated the value of combined and sub-stratified imaging assessments with MG and US over breast cancer subtypes (BCS.Medical records of 5,037 cases having imaging-guided core biopsy, performed from 2009 to 2012, were retrospectively reviewed. This study selected 1,995 cases (1,457 benign and 538 invasive cancer having both MG and US before biopsy. These cases were categorized with the "5-point score" for their MG and US, and applied for combined and sub-stratified imaging assessments. Invasive cancers were classified on the basis of BCS, and correlated with combined and sub-stratified imaging assessments.These selected cases were evaluated by the "5-point score." MG, US, and combined and sub-stratified imaging assessments all revealed statistically significant (P < 0.001 incidence of malignancy. The sensitivity was increased in the combined imaging score (99.8%, and the specificity was increased in the sub-stratified combined score (75.4%. In the sub-stratified combined imaging assessment, all BCS can be classified with higher scores (abnormality hierarchy, and luminal B subtype showed the most salient result (hierarchy: higher, 95%; lower, 5%.Combined and sub-stratified imaging assessments can increase sensitivity and specificity of breast cancer diagnosis, respectively, and Luminal B subtype shows the best identification by sub-stratified combined imaging scoring.

Diagnostic accuracy of the STRATIFY clinical prediction rule for falls: A systematic review and meta-analysis

LENUS (Irish Health Repository)

Billington, Jennifer

2012-08-07

AbstractBackgroundThe STRATIFY score is a clinical prediction rule (CPR) derived to assist clinicians to identify patients at risk of falling. The purpose of this systematic review and meta-analysis is to determine the overall diagnostic accuracy of the STRATIFY rule across a variety of clinical settings.MethodsA literature search was performed to identify all studies that validated the STRATIFY rule. The methodological quality of the studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. A STRATIFY score of ≥2 points was used to identify individuals at higher risk of falling. All included studies were combined using a bivariate random effects model to generate pooled sensitivity and specificity of STRATIFY at ≥2 points. Heterogeneity was assessed using the variance of logit transformed sensitivity and specificity.ResultsSeventeen studies were included in our meta-analysis, incorporating 11,378 patients. At a score ≥2 points, the STRATIFY rule is more useful at ruling out falls in those classified as low risk, with a greater pooled sensitivity estimate (0.67, 95% CI 0.52–0.80) than specificity (0.57, 95% CI 0.45 – 0.69). The sensitivity analysis which examined the performance of the rule in different settings and subgroups also showed broadly comparable results, indicating that the STRATIFY rule performs in a similar manner across a variety of different ‘at risk’ patient groups in different clinical settings.ConclusionThis systematic review shows that the diagnostic accuracy of the STRATIFY rule is limited and should not be used in isolation for identifying individuals at high risk of falls in clinical practice.

[Effect of mass communication media in food purchasing at the family level].

Science.gov (United States)

Moya de Sifontes, M Z; Dehollain, P L

1986-03-01

The main purpose of this study was to determine the effect of mass media advertisement of food products (TV, radio and the press), particularly in pre-school and school-age children, as well as the concomitant impact these age groups have on the family food buying patterns. To test the hypothesis that the impact of mass media advertising on foods varied in the different socioeconomic levels of a community, a stratified sample of all children below 13 years of age, who attended the Francisco Fajardo school in the central coast of Venezuela, was drawn. Mass media contact, food and nutrition knowledge and other socioeconomic characteristics were related to the family's food-buying patterns. More specifically, the age, working status and educational level of the mother in regard to beliefs concerning the nutritional value of advertized food products, were related. A semi-structured questionnaire was designed, tested and applied to the housewife or whoever performed this role within the family. Findings revealed that families of low socioeconomic status are prone to be most influenced by mass media food product advertising. This is reflected not only in food purchasing practices but also in food consumption patterns at the family level. Chocolate drinks, cereals, jello, sausages, and ice cream are the most popular products among pre-school and school-aged children, without social class distinction. Furthermore, results revealed that the degree of exposure to mass communication media--television, radio and newspapers--is a determining factor in children's food preferences at all socioeconomic levels, and that television is the media exerting the greatest influence.

General Practitioners' and patients' perceptions towards stratified care: a theory informed investigation.

Science.gov (United States)

Saunders, Benjamin; Bartlam, Bernadette; Foster, Nadine E; Hill, Jonathan C; Cooper, Vince; Protheroe, Joanne

2016-08-31

Stratified primary care involves changing General Practitioners' (GPs) clinical behaviour in treating patients, away from the current stepped care approach to instead identifying early treatment options that are matched to patients' risk of persistent disabling pain. This article explores the perspectives of UK-based GPs and patients about a prognostic stratified care model being developed for patients with the five most common primary care musculoskeletal pain presentations. The focus was on views about acceptability, and anticipated barriers and facilitators to the use of stratified care in routine practice. Four focus groups and six semi-structured telephone interviews were conducted with GPs (n = 23), and three focus groups with patients (n = 20). Data were analysed thematically; and identified themes examined in relation to the Theoretical Domains Framework (TDF), which facilitates comprehensive identification of behaviour change determinants. A critical approach was taken in using the TDF, examining the nuanced interrelationships between theoretical domains. Four key themes were identified: Acceptability of clinical decision-making guided by stratified care; impact on the therapeutic relationship; embedding a prognostic approach within a biomedical model; and practical issues in using stratified care. Whilst within each theme specific findings are reported, common across themes was the identified relationships between the theoretical domains of knowledge, skills, professional role and identity, environmental context and resources, and goals. Through analysis of these identified relationships it was found that, for GPs and patients to perceive stratified care as being acceptable, it must be seen to enhance GPs' knowledge and skills, not undermine GPs' and patients' respective identities and be integrated within the environmental context of the consultation with minimal disruption. Findings highlight the importance of taking into account the context of

Ethanol dehydration to ethylene in a stratified autothermal millisecond reactor.

Science.gov (United States)

Skinner, Michael J; Michor, Edward L; Fan, Wei; Tsapatsis, Michael; Bhan, Aditya; Schmidt, Lanny D

2011-08-22

The concurrent decomposition and deoxygenation of ethanol was accomplished in a stratified reactor with 50-80 ms contact times. The stratified reactor comprised an upstream oxidation zone that contained Pt-coated Al(2)O(3) beads and a downstream dehydration zone consisting of H-ZSM-5 zeolite films deposited on Al(2)O(3) monoliths. Ethanol conversion, product selectivity, and reactor temperature profiles were measured for a range of fuel:oxygen ratios for two autothermal reactor configurations using two different sacrificial fuel mixtures: a parallel hydrogen-ethanol feed system and a series methane-ethanol feed system. Increasing the amount of oxygen relative to the fuel resulted in a monotonic increase in ethanol conversion in both reaction zones. The majority of the converted carbon was in the form of ethylene, where the ethanol carbon-carbon bonds stayed intact while the oxygen was removed. Over 90% yield of ethylene was achieved by using methane as a sacrificial fuel. These results demonstrate that noble metals can be successfully paired with zeolites to create a stratified autothermal reactor capable of removing oxygen from biomass model compounds in a compact, continuous flow system that can be configured to have multiple feed inputs, depending on process restrictions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysing stratified medicine business models and value systems: innovation-regulation interactions.

Science.gov (United States)

Mittra, James; Tait, Joyce

2012-09-15

Stratified medicine offers both opportunities and challenges to the conventional business models that drive pharmaceutical R&D. Given the increasingly unsustainable blockbuster model of drug development, due in part to maturing product pipelines, alongside increasing demands from regulators, healthcare providers and patients for higher standards of safety, efficacy and cost-effectiveness of new therapies, stratified medicine promises a range of benefits to pharmaceutical and diagnostic firms as well as healthcare providers and patients. However, the transition from 'blockbusters' to what might now be termed 'niche-busters' will require the adoption of new, innovative business models, the identification of different and perhaps novel types of value along the R&D pathway, and a smarter approach to regulation to facilitate innovation in this area. In this paper we apply the Innogen Centre's interdisciplinary ALSIS methodology, which we have developed for the analysis of life science innovation systems in contexts where the value creation process is lengthy, expensive and highly uncertain, to this emerging field of stratified medicine. In doing so, we consider the complex collaboration, timing, coordination and regulatory interactions that shape business models, value chains and value systems relevant to stratified medicine. More specifically, we explore in some depth two convergence models for co-development of a therapy and diagnostic before market authorisation, highlighting the regulatory requirements and policy initiatives within the broader value system environment that have a key role in determining the probable success and sustainability of these models. Copyright © 2012 Elsevier B.V. All rights reserved.

Inviscid incompressible limits of strongly stratified fluids

Czech Academy of Sciences Publication Activity Database

Feireisl, Eduard; Jin, B.J.; Novotný, A.

2014-01-01

Roč. 89, 3-4 (2014), s. 307-329 ISSN 0921-7134 R&D Projects: GA ČR GA201/09/0917 Institutional support: RVO:67985840 Keywords : compressible Navier-Stokes system * anelastic approximation * stratified fluid Subject RIV: BA - General Mathematics Impact factor: 0.528, year: 2014 http://iospress.metapress.com/content/d71255745tl50125/?p=969b60ae82634854ab8bd25505ce1f71&pi=3

Finite element and network electrical simulation of rotating magnetofluid flow in nonlinear porous media with inclined magnetic field and hall currents

Directory of Open Access Journals (Sweden)

Bég Anwar O.

2014-01-01

Full Text Available A mathematical model is presented for viscous hydromagnetic flow through a hybrid non-Darcy porous media rotating generator. The system is simulated as steady, incompressible flow through a nonlinear porous regime intercalated between parallel plates of the generator in a rotating frame of reference in the presence of a strong, inclined magnetic field A pressure gradient term is included which is a function of the longitudinal coordinate. The general equations for rotating viscous magnetohydrodynamic flow are presented and neglecting convective acceleration effects, the two-dimensional viscous flow equations are derived incorporating current density components, porous media drag effects, Lorentz drag force components and Hall current effects. Using an appropriate group of dimensionless variables, the momentum equations for primary and secondary flow are rendered nondimensional and shown to be controlled by six physical parameters-Hartmann number (Ha, Hall current parameter (Nh, Darcy number (Da, Forchheimer number (Fs, Ekman number (Ek and dimensionless pressure gradient parameter (Np, in addition to one geometric parameter-the orientation of the applied magnetic field (θ . Several special cases are extracted from the general model, including the non-porous case studied earlier by Ghosh and Pop (2006. A numerical solution is presented to the nonlinear coupled ordinary differential equations using both the Network Simulation Method and Finite Element Method, achieving excellent agreement. Additionally very good agreement is also obtained with the earlier analytical solutions of Ghosh and Pop (2006. for selected Ha, Ek and Nh values. We examine in detail the effects of magnetic field, rotation, Hall current, bulk porous matrix drag, second order porous impedance, pressure gradient and magnetic field inclination on primary and secondary velocity distributions and also frictional shear stresses at the plates. Primary velocity is seen to decrease

The role of social media networks in psychotic disorders: a case report.

Science.gov (United States)

Krishna, Nithin; Fischer, Bernard A; Miller, Moshe; Register-Brown, Kelly; Patchan, Kathleen; Hackman, Ann

2013-01-01

We report the case of a young man diagnosed with schizophrenia who presented with stalking behaviors that may have been caused by problematic use or participation in social media networks (SMN). We review the possible role of SMN in the formation of his romantic delusion and offer suggestions for clinicians around incorporation of SMN questions into assessments. It is imperative to identify populations at risk of SMN-related stalking behaviors to stratify mental health resources and interventions. Additional studies are needed to further clarify the role of SMN in psychotic disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

RANS Modeling of Stably Stratified Turbulent Boundary Layer Flows in OpenFOAM®

Directory of Open Access Journals (Sweden)

Wilson Jordan M.

2015-01-01

Full Text Available Quantifying mixing processes relating to the transport of heat, momentum, and scalar quantities of stably stratified turbulent geophysical flows remains a substantial task. In a stably stratified flow, such as the stable atmospheric boundary layer (SABL, buoyancy forces have a significant impact on the flow characteristics. This study investigates constant and stability-dependent turbulent Prandtl number (Prt formulations linking the turbulent viscosity (νt and diffusivity (κt for modeling applications of boundary layer flows. Numerical simulations of plane Couette flow and pressure-driven channel flow are performed using the Reynolds-averaged Navier-Stokes (RANS framework with the standard k-ε turbulence model. Results are compared with DNS data to evaluate model efficacy for predicting mean velocity and density fields. In channel flow simulations, a Prandtl number formulation for wall-bounded flows is introduced to alleviate overmixing of the mean density field. This research reveals that appropriate specification of Prt can improve predictions of stably stratified turbulent boundary layer flows.

Mechanisms and Variability of Salt Transport in Partially-Stratified Estuaries

National Research Council Canada - National Science Library

Bowen, Melissa

2000-01-01

.... Analysis of salt transport from observations in the Hudson Estuary show that stratified periods with elevated estuarine salt transport occur in five-day intervals once a month during apogean neap tides...

Unit Stratified Sampling as a Tool for Approximation of Stochastic Optimization Problems

Czech Academy of Sciences Publication Activity Database

Šmíd, Martin

2012-01-01

Roč. 19, č. 30 (2012), s. 153-169 ISSN 1212-074X R&D Projects: GA ČR GAP402/11/0150; GA ČR GAP402/10/0956; GA ČR GA402/09/0965 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : Stochastic programming * approximation * stratified sampling Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2013/E/smid-unit stratified sampling as a tool for approximation of stochastic optimization problems.pdf

Inhibition of Rho-associated kinases disturbs the collective cell migration of stratified TE-10 cells

Directory of Open Access Journals (Sweden)

Taro Mikami

2015-01-01

Full Text Available BACKGROUND: The collective cell migration of stratified epithelial cells is considered to be an important phenomenon in wound healing, development, and cancer invasion; however, little is known about the mechanisms involved. Furthermore, whereas Rho family proteins, including RhoA, play important roles in cell migration, the exact role of Rho-associated coiled coil-containing protein kinases (ROCKs in cell migration is controversial and might be cell-type dependent. Here, we report the development of a novel modified scratch assay that was used to observe the collective cell migration of stratified TE-10 cells derived from a human esophageal cancer specimen. RESULTS: Desmosomes were found between the TE-10 cells and microvilli of the surface of the cell sheet. The leading edge of cells in the cell sheet formed a simple layer and moved forward regularly; these rows were followed by the stratified epithelium. ROCK inhibitors and ROCK small interfering RNAs (siRNAs disturbed not only the collective migration of the leading edge of this cell sheet, but also the stratified layer in the rear. In contrast, RhoA siRNA treatment resulted in more rapid migration of the leading rows and disturbed movement of the stratified portion. CONCLUSIONS: The data presented in this study suggest that ROCKs play an important role in mediating the collective migration of TE-10 cell sheets. In addition, differences between the effects of siRNAs targeting either RhoA or ROCKs suggested that distinct mechanisms regulate the collective cell migration in the simple epithelium of the wound edge versus the stratified layer of the epithelium.

Stereo imaging and random array stratified imaging for cargo radiation inspecting

International Nuclear Information System (INIS)

Wang Jingjin; Zeng Yu

2003-01-01

This paper presents a Stereo Imaging and Random Array Stratified Imaging for cargo container radiation Inspecting. By using dual-line vertical detector array scan, a stereo image of inspected cargo can be obtained and watched with virtual reality view. The random detector array has only one-row of detectors but distributed in a certain horizontal dimension randomly. To scan a cargo container with this random array detector, a 'defocused' image is obtained. By using 'anti-random focusing', one layer of the image can be focused on the background of all defocused images from other layers. A stratified X-ray image of overlapped bike wheels is presented

Adjunctive social media for more effective contraceptive counseling: a randomized controlled trial.

Science.gov (United States)

Kofinas, Jason D; Varrey, Aneesha; Sapra, Katherine J; Kanj, Rula V; Chervenak, Frank A; Asfaw, Tirsit

2014-04-01

To determine whether social media, specifically Facebook, is an effective tool for improving contraceptive knowledge. English-speaking women aged 18-45 years receiving care at an urban academic center obstetrics and gynecology clinic were included and randomized to a trial of standard contraceptive education and pamphlet (n=74) compared with standard contraceptive education and Facebook (n=69) information for contraception counseling. Contraceptive knowledge was evaluated preintervention and postintervention by the Contraceptive Knowledge Inventory. We evaluated the effect of the intervention by raw score and percent increase in Contraceptive Knowledge Inventory score, participant satisfaction with counseling method, and contraceptive preference postintervention. All analyses were stratified by age group. The median raw postintervention Contraceptive Knowledge Inventory score was significantly higher in the Facebook compared with the pamphlet group (15 compared with 12, PSocial media as an adjunct to traditional in-office counseling improves patient contraceptive knowledge and increases patient preference for LARCs. ClinicalTrials.gov, www.clinicaltrials.gov, NCT01994005.

Stratified charge rotary engine combustion studies

Science.gov (United States)

Shock, H.; Hamady, F.; Somerton, C.; Stuecken, T.; Chouinard, E.; Rachal, T.; Kosterman, J.; Lambeth, M.; Olbrich, C.

1989-07-01

Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

Media Education Initiatives by Media Organizations: The Uses of Media Literacy in Hong Kong Media

Science.gov (United States)

Chu, Donna; Lee, Alice Y. L.

2014-01-01

As more media organizations have engaged in media education, this paper investigates the goals and practices of these activities. This article coins media education initiatives by media organizations with the term "media-organization media literac"y (MOML). Four MOML projects in Hong Kong were selected for examination. Built on critical…

Sensitivity and inversion of full seismic waveforms in stratified porous medium

International Nuclear Information System (INIS)

Barros, L. de

2007-12-01

Characterization of porous media parameters, and particularly the porosity, permeability and fluid properties are very useful in many applications (hydrologic, natural hazards or oil industry). The aim of my research is to evaluate the possibility to determine these properties from the full seismic wave fields. First, I am interested in the useful parameters and the specific properties of the seismic waves in the poro-elastic theory, often called Biot (1956) theory. I then compute seismic waves propagation in fluid saturated stratified porous media with a reflectivity method coupled with the discrete wavenumber integration method. I first used this modeling to study the possibilities to determine the carbon dioxide concentration and localization thanks to the reflected P-waves in the case of the deep geological storage of Sleipner (North Sea). The sensitivity of the seismic response to the poro-elastic parameters are then generalized by the analytical computation of the Frechet derivatives which are expressed in terms of the Green's functions of the unperturbed medium. The numerical tests show that the porosity and the consolidation are the main parameters to invert. The sensitivity operators are then introduced in a inversion algorithm based on iterative modeling of the full waveform. The classical algorithm of generalized least-square inverse problem is solved by the quasi-Newton technique (Tarantola, 1984). The inversion of synthetic data show that we can invert for the porosity and the fluid and solid parameters (densities and mechanical modulus, or volume rate of fluid and mineral) can be correctly rebuilt if the other parameters are well known. However, the strong seismic coupling of the porous parameters leads to difficulties to invert simultaneously for several parameters. One way to get round these difficulties is to use additional information and invert for one single parameter for the fluid properties (saturating rate) or for the lithology. An other way

Equipment for extracting and conveying stratified minerals

Energy Technology Data Exchange (ETDEWEB)

Blumenthal, G.; Kunzer, H.; Plaga, K.

1991-08-14

This invention relates to equipment for extracting stratified minerals and conveying the said minerals along the working face, comprising a trough shaped conveyor run assembled from lengths, a troughed extraction run in lengths matching the lengths of conveyor troughing, which is linked to the top edge of the working face side of the conveyor troughing with freedom to swivel vertically, and a positively guided chain carrying extraction tools and scrapers along the conveyor and extraction runs.

A mechanically enhanced hybrid nano-stratified barrier with a defect suppression mechanism for highly reliable flexible OLEDs.

Science.gov (United States)

Jeong, Eun Gyo; Kwon, Seonil; Han, Jun Hee; Im, Hyeon-Gyun; Bae, Byeong-Soo; Choi, Kyung Cheol

2017-05-18

Understanding the mechanical behaviors of encapsulation barriers under bending stress is important when fabricating flexible organic light-emitting diodes (FOLEDs). The enhanced mechanical characteristics of a nano-stratified barrier were analyzed based on a defect suppression mechanism, and then experimentally demonstrated. Following the Griffith model, naturally-occurring cracks, which were caused by Zn etching at the interface of the nano-stratified structure, can curb the propagation of defects. Cross-section images after bending tests provided remarkable evidence to support the existence of a defect suppression mechanism. Many visible cracks were found in a single Al 2 O 3 layer, but not in the nano-stratified structure, due to the mechanism. The nano-stratified structure also enhanced the barrier's physical properties by changing the crystalline phase of ZnO. In addition, experimental results demonstrated the effect of the mechanism in various ways. The nano-stratified barrier maintained a low water vapor transmission rate after 1000 iterations of a 1 cm bending radius test. Using this mechanically enhanced hybrid nano-stratified barrier, FOLEDs were successfully encapsulated without losing mechanical or electrical performance. Finally, comparative lifetime measurements were conducted to determine reliability. After 2000 hours of constant current driving and 1000 iterations with a 1 cm bending radius, the FOLEDs retained 52.37% of their initial luminance, which is comparable to glass-lid encapsulation, with 55.96% retention. Herein, we report a mechanically enhanced encapsulation technology for FOLEDs using a nano-stratified structure with a defect suppression mechanism.

Evaluation of a Stratified National Breast Screening Program in the United Kingdom : An Early Model-Based Cost-Effectiveness Analysis

NARCIS (Netherlands)

Gray, Ewan; Donten, Anna; Karssemeijer, Nico; van Gils, Carla; Evans, D. Gareth R.; Astley, Sue; Payne, Katherine

Objectives: To identify the incremental costs and consequences of stratified national breast screening programs (stratified NBSPs) and drivers of relative cost-effectiveness. Methods: A decision-analytic model (discrete event simulation) was conceptualized to represent four stratified NBSPs (risk 1,

Evaluation of a Stratified National Breast Screening Program in the United Kingdom: An Early Model-Based Cost-Effectiveness Analysis

NARCIS (Netherlands)

Gray, E.; Donten, A.; Karssemeijer, N.; Gils, C. van; Evans, D.G.; Astley, S.; Payne, K.

2017-01-01

OBJECTIVES: To identify the incremental costs and consequences of stratified national breast screening programs (stratified NBSPs) and drivers of relative cost-effectiveness. METHODS: A decision-analytic model (discrete event simulation) was conceptualized to represent four stratified NBSPs (risk 1,

Crenothrix are major methane consumers in stratified lakes.

Science.gov (United States)

Oswald, Kirsten; Graf, Jon S; Littmann, Sten; Tienken, Daniela; Brand, Andreas; Wehrli, Bernhard; Albertsen, Mads; Daims, Holger; Wagner, Michael; Kuypers, Marcel Mm; Schubert, Carsten J; Milucka, Jana

2017-09-01

Methane-oxidizing bacteria represent a major biological sink for methane and are thus Earth's natural protection against this potent greenhouse gas. Here we show that in two stratified freshwater lakes a substantial part of upward-diffusing methane was oxidized by filamentous gamma-proteobacteria related to Crenothrix polyspora. These filamentous bacteria have been known as contaminants of drinking water supplies since 1870, but their role in the environmental methane removal has remained unclear. While oxidizing methane, these organisms were assigned an 'unusual' methane monooxygenase (MMO), which was only distantly related to 'classical' MMO of gamma-proteobacterial methanotrophs. We now correct this assignment and show that Crenothrix encode a typical gamma-proteobacterial PmoA. Stable isotope labeling in combination swith single-cell imaging mass spectrometry revealed methane-dependent growth of the lacustrine Crenothrix with oxygen as well as under oxygen-deficient conditions. Crenothrix genomes encoded pathways for the respiration of oxygen as well as for the reduction of nitrate to N 2 O. The observed abundance and planktonic growth of Crenothrix suggest that these methanotrophs can act as a relevant biological sink for methane in stratified lakes and should be considered in the context of environmental removal of methane.

Crystallization of a compositionally stratified basal magma ocean

Science.gov (United States)

Laneuville, Matthieu; Hernlund, John; Labrosse, Stéphane; Guttenberg, Nicholas

2018-03-01

Earth's ∼3.45 billion year old magnetic field is regenerated by dynamo action in its convecting liquid metal outer core. However, convection induces an isentropic thermal gradient which, coupled with a high core thermal conductivity, results in rapid conducted heat loss. In the absence of implausibly high radioactivity or alternate sources of motion to drive the geodynamo, the Earth's early core had to be significantly hotter than the melting point of the lower mantle. While the existence of a dense convecting basal magma ocean (BMO) has been proposed to account for high early core temperatures, the requisite physical and chemical properties for a BMO remain controversial. Here we relax the assumption of a well-mixed convecting BMO and instead consider a BMO that is initially gravitationally stratified owing to processes such as mixing between metals and silicates at high temperatures in the core-mantle boundary region during Earth's accretion. Using coupled models of crystallization and heat transfer through a stratified BMO, we show that very high temperatures could have been trapped inside the early core, sequestering enough heat energy to run an ancient geodynamo on cooling power alone.

Nonlinear hydromagnetic Rayleigh-Taylor instability for strong viscous fluids in porous media

CERN Document Server

El-Dib, Y O

2003-01-01

In the present work a weakly nonlinear stability for magnetic fluid is discussed. The research of an interface between two strong viscous homogeneous incompressible fluids through porous medium is investigated theoretically and graphically. The effect of the vertical magnetic field has been demonstrated in this study. The linear form of equation of motion is solved in the light of the nonlinear boundary conditions. The boundary value problem leads to construct nonlinear characteristic equation having complex coefficients in elevation function. The nonlinearity is kept to third-order expansion. The nonlinear characteristic equation leads to derive the well-known nonlinear Schroedinger equation. This equation having complex coefficients of the disturbance amplitude varies in both space and time. Stability criteria have been performed for nonlinear Chanderasekhar dispersion relation including the porous effects. Stability conditions are discussed through the assumption of equal kinematic viscosity. The calculati...

Media Komunitas dan Media Literacy

Directory of Open Access Journals (Sweden)

Pawito .

2013-12-01

Full Text Available Abstract:This essay deals with community media in relation to media literacy. After a short discussion on a number of community media characters is made the essay goes further with somewhat detail theoretical presumptions of the roles of media community with respect primarily to the development as Amartya Sen mentioned about. The author suggests that community media may play some significant roles in the development including (a disseminating information (from varieties of perspective, (b facilitating public discussion, (c helping to reach solutions of problems, (d encouraging participations, and (e encouraging the development of media literacy. Regarding the last point the author remarks that media community may have a dual-roles i.e facilitating community’s member in media participation and facilitating community’s member in media education.

High-order boundary integral equation solution of high frequency wave scattering from obstacles in an unbounded linearly stratified medium

Science.gov (United States)

Barnett, Alex H.; Nelson, Bradley J.; Mahoney, J. Matthew

2015-09-01

We apply boundary integral equations for the first time to the two-dimensional scattering of time-harmonic waves from a smooth obstacle embedded in a continuously-graded unbounded medium. In the case we solve, the square of the wavenumber (refractive index) varies linearly in one coordinate, i.e. (Δ + E +x2) u (x1 ,x2) = 0 where E is a constant; this models quantum particles of fixed energy in a uniform gravitational field, and has broader applications to stratified media in acoustics, optics and seismology. We evaluate the fundamental solution efficiently with exponential accuracy via numerical saddle-point integration, using the truncated trapezoid rule with typically 102 nodes, with an effort that is independent of the frequency parameter E. By combining with a high-order Nyström quadrature, we are able to solve the scattering from obstacles 50 wavelengths across to 11 digits of accuracy in under a minute on a desktop or laptop.

Turbulent circulation above the surface heat source in stably stratified atmosphere

Science.gov (United States)

Kurbatskii, A. F.; Kurbatskaya, L. I.

2016-10-01

The 3-level RANS approach for simulating a turbulent circulation over the heat island in a stably stratified environment under nearly calm conditions is formulated. The turbulent kinetic energy its spectral consumption (dissipation) and the dispersion of turbulent fluctuations of temperature are found from differential equations, thus the correct modeling of transport processes in the interface layer with the counter-gradient heat flux is assured. The three-parameter turbulence RANS approach minimizes difficulties in simulating the turbulent transport in a stably stratified environment and reduces efforts needed for the numerical implementation of the 3-level RANS approach. Numerical simulation of the turbulent structure of the penetrative convection over the heat island under conditions of stably stratified atmosphere demonstrates that the three-equation model is able to predict the thermal circulation induced by the heat island. The temperature distribution, root-mean-square fluctuations of the turbulent velocity and temperature fields and spectral turbulent kinetic energy flux are in good agreement with the experimental data. The model describes such thin physical effects, as a crossing of vertical profiles of temperature of a thermal plume with the formation of the negative buoyancy area testifying to development of the dome-shaped form at the top part of a plume in the form of "hat".

Écoulement polyphasique dans un milieu poreux stratifié. Résultats expérimentaux et interprétation par la méthode de prise de moyenne à grande échelle Multiphase Flow in Stratified Porous Media Experimental Results and Interpretation by the Large-Scale Averaging Method

Directory of Open Access Journals (Sweden)

Bertin H.

2006-11-01

Full Text Available Nous abordons l'étude des écoulements polyphasiques en milieu poreux hétérogène d'un point de vue théorique (méthodologie de la prise de moyenne à grande échelle et expérimental. Dans une première partie nous présentons la méthodologie permettant d'obtenir les équations à grande échelle. Le point de départ de l'étude est les équations locales, analogues aux équations de Darcy généralisées obtenues par prise de moyenne des équations de Stokes à l'échelle du pore. La prise de moyenne à grande échelle de ces équations permet d'écrire un système d'équations où les coefficients de transport équivalents sont calculés à partir des données locales, par la résolution d'un problème de fermeture explicité dans le cas quasi-statique (effets capillaires dominants. La seconde partie de notre travail concerne l'étude expérimentale d'un écoulement eau-huile dans un milieu poreux stratifié constitué de deux régions de caractéristiques physiques différentes. Les champs de saturation bidimensionnels sont mesurés tout au long de l'imbibition par absorption d'un rayonnement gamma. Les résultats expérimentaux, évolution de la fraction volumique moyenne par section en fonction du temps, sont comparés aux résultats d'une simulation numérique des équations de transport où les coefficients utilisés ont été déterminés par la méthode de prise de moyenne à grande échelle. Two-phase flow in heterogeneous porous media is studied from a theoretical point of view (the large-scale averaging method and experimentally. In the first part, we present the methodology leading to the large-scale equations. The starting point of the study is the local equation, analogous to the generalized Darcy's law obtained by averaging the Stokes equation at the pore level. The large-scale averaging of these equations leads to a system where the equivalent transport coefficients are computed from the local data by solving a closure

Degradation of organic dyes using spray deposited nanocrystalline stratified WO3/TiO2 photoelectrodes under sunlight illumination

Science.gov (United States)

Hunge, Y. M.; Yadav, A. A.; Mahadik, M. A.; Bulakhe, R. N.; Shim, J. J.; Mathe, V. L.; Bhosale, C. H.

2018-02-01

The need to utilize TiO2 based metal oxide hetero nanostructures for the degradation of environmental pollutants like Rhodamine B and reactive red 152 from the wastewater using stratified WO3/TiO2 catalyst under sunlight illumination. WO3, TiO2 and stratified WO3/TiO2 catalysts were prepared by a spray pyrolysis method. It was found that the stratified WO3/TiO2 heterostructure has high crystallinity, no mixed phase formation occurs, strong optical absorption in the visible region of the solar spectrum, and large surface area. The photocatalytic activity was tested for degradation of Rhodamine B (Rh B) and reactive red 152 in an aqueous medium. TiO2 layer in stratified WO3/TiO2 catalyst helps to extend its absorption spectrum in the solar light region. Rh B and Reactive red 152is eliminated up to 98 and 94% within the 30 and 40 min respectively at optimum experimental condition by stratified WO3/TiO2. Moreover, stratified WO3/TiO2 photoelectrode has good stability and reusability than individual TiO2 and WO3 thin film in the degradation of Rh B and reactive red 152. The photoelectrocatalytic experimental results indicate that stratified WO3/TiO2 photoelectrode is a promising material for dye removal.

Identification of major planktonic sulfur oxidizers in stratified freshwater lake.

Directory of Open Access Journals (Sweden)

Hisaya Kojima

Full Text Available Planktonic sulfur oxidizers are important constituents of ecosystems in stratified water bodies, and contribute to sulfide detoxification. In contrast to marine environments, taxonomic identities of major planktonic sulfur oxidizers in freshwater lakes still remain largely unknown. Bacterioplankton community structure was analyzed in a stratified freshwater lake, Lake Mizugaki in Japan. In the clone libraries of 16S rRNA gene, clones very closely related to a sulfur oxidizer isolated from this lake, Sulfuritalea hydrogenivorans, were detected in deep anoxic water, and occupied up to 12.5% in each library of different water depth. Assemblages of planktonic sulfur oxidizers were specifically analyzed by constructing clone libraries of genes involved in sulfur oxidation, aprA, dsrA, soxB and sqr. In the libraries, clones related to betaproteobacteria were detected with high frequencies, including the close relatives of Sulfuritalea hydrogenivorans.

Mixing of stratified flow around bridge piers in steady current

DEFF Research Database (Denmark)

Jensen, Bjarne; Carstensen, Stefan; Christensen, Erik Damgaard

2018-01-01

This paper presents the results of an experimental and numerical investigation of the mixing of stratified flow around bridge pier structures. In this study, which was carried out in connection with the Fehmarnbelt Fixed Link environmental impact assessment, the mixing processes of two-layer stra......This paper presents the results of an experimental and numerical investigation of the mixing of stratified flow around bridge pier structures. In this study, which was carried out in connection with the Fehmarnbelt Fixed Link environmental impact assessment, the mixing processes of two......-layer stratification was studied in which the lower level had a higher salinity than the upper layer. The physical experiments investigated two different pier designs. A general study was made regarding forces on the piers in which the effect of the current angle relative to the structure was also included...

Quantum image pseudocolor coding based on the density-stratified method

Science.gov (United States)

Jiang, Nan; Wu, Wenya; Wang, Luo; Zhao, Na

2015-05-01

Pseudocolor processing is a branch of image enhancement. It dyes grayscale images to color images to make the images more beautiful or to highlight some parts on the images. This paper proposes a quantum image pseudocolor coding scheme based on the density-stratified method which defines a colormap and changes the density value from gray to color parallel according to the colormap. Firstly, two data structures: quantum image GQIR and quantum colormap QCR are reviewed or proposed. Then, the quantum density-stratified algorithm is presented. Based on them, the quantum realization in the form of circuits is given. The main advantages of the quantum version for pseudocolor processing over the classical approach are that it needs less memory and can speed up the computation. Two kinds of examples help us to describe the scheme further. Finally, the future work are analyzed.

Suppression of stratified explosive interactions

Energy Technology Data Exchange (ETDEWEB)

Meeks, M.K.; Shamoun, B.I.; Bonazza, R.; Corradini, M.L. [Wisconsin Univ., Madison, WI (United States). Dept. of Nuclear Engineering and Engineering Physics

1998-01-01

Stratified Fuel-Coolant Interaction (FCI) experiments with Refrigerant-134a and water were performed in a large-scale system. Air was uniformly injected into the coolant pool to establish a pre-existing void which could suppress the explosion. Two competing effects due to the variation of the air flow rate seem to influence the intensity of the explosion in this geometrical configuration. At low flow rates, although the injected air increases the void fraction, the concurrent agitation and mixing increases the intensity of the interaction. At higher flow rates, the increase in void fraction tends to attenuate the propagated pressure wave generated by the explosion. Experimental results show a complete suppression of the vapor explosion at high rates of air injection, corresponding to an average void fraction of larger than 30%. (author)

Monte Carlo stratified source-sampling

International Nuclear Information System (INIS)

Blomquist, R.N.; Gelbard, E.M.

1997-01-01

In 1995, at a conference on criticality safety, a special session was devoted to the Monte Carlo open-quotes eigenvalue of the worldclose quotes problem. Argonne presented a paper, at that session, in which the anomalies originally observed in that problem were reproduced in a much simplified model-problem configuration, and removed by a version of stratified source-sampling. The original test-problem was treated by a special code designed specifically for that purpose. Recently ANL started work on a method for dealing with more realistic eigenvalue of the world configurations, and has been incorporating this method into VIM. The original method has been modified to take into account real-world statistical noise sources not included in the model problem. This paper constitutes a status report on work still in progress

From Augmentation Media to Meme Media.

Science.gov (United States)

Tanaka, Yuzuru

Computers as meta media are now evolving from augmentation media vehicles to meme media vehicles. While an augmentation media system provides a seamlessly integrated environment of various tools and documents, meme media system provides further functions to edit and distribute tools and documents. Documents and tools on meme media can easily…

Using the Internet to Support Exercise and Diet: A Stratified Norwegian Survey.

Science.gov (United States)

Wangberg, Silje C; Sørensen, Tove; Andreassen, Hege K

2015-08-26

Internet is used for a variety of health related purposes. Use differs and has differential effects on health according to socioeconomic status. We investigated to what extent the Norwegian population use the Internet to support exercise and diet, what kind of services they use, and whether there are social disparities in use. We expected to find differences according to educational attainment. In November 2013 we surveyed a stratified sample of 2196 persons drawn from a Web panel of about 50,000 Norwegians over 15 years of age. The questionnaire included questions about using the Internet, including social network sites (SNS), or mobile apps in relation to exercise or diet, as well as background information about education, body image, and health. The survey email was opened by 1187 respondents (54%). Of these, 89 did not click on the survey hyperlink (declined to participate), while another 70 did not complete the survey. The final sample size is thus 1028 (87% response rate). Compared to the Norwegian census the sample had a slight under-representation of respondents under the age of 30 and with low education. The data was weighted accordingly before analyses. Sixty-nine percent of women and 53% of men had read about exercise or diet on the Internet (χ(2)= 25.6, Psocial disparities in health, and continue to monitor population use. For Internet- and mobile-based interventions to support health behaviors, this study provides information relevant to tailoring of delivery media and components to user.

Social media management and media environment

Directory of Open Access Journals (Sweden)

Šiđanin Iva

2012-01-01

Full Text Available The paper deals with the system of services that social media management can offer to a variety of users. As social media systems are emerging, social media management can strengthen teams in social media and help to manage numerous social channels and distribution of social information from one place. Social media management is a system of procedures that are used to manage the flow of information in the environment of social media. This involves connecting with social media like Facebook, Twitter, LinkedIn, Plaxo, Ecademy, YouTube and many others, then the aggregation and management of social data. Social media management services are analysed through various fields, such as managing multiple social media profiles, mail scheduling and filtering, reporting and analytics. Social media management enables managing personal business through social media, which contributes to a significant reduction in expenditures. The paper also discusses the importance of social media management in marketing activities and various forms of social promotion, which allow companies to easily reach their customers.

Changing the Rules of the Game: How Do We Measure Success in Social Media?

Science.gov (United States)

Hogan, Aisling M; Winter, Desmond C

2017-09-01

Ours will be the generation proud to say we shifted the sands of educational deserts by open access and proliferation, seeding of data sharing, and watering grassroots research in resource-compromised environments. Universal "social" media is defining features of modern professional life that provide powerful modes of knowledge acquisition/sharing to that end. Altmetric and other measurements stratify academic communications according to this alternate, online media presence (not academic penetrance). Are they meaningless, self-absorbed integers, or reliable yardsticks of scientific and educational prowess? Far beyond this trite, patronizing question from the minds of outdated, terrified technophobes, the real impact of "social" media is not narcissistic solipsism. Instant dissemination of contemporary surgical controversies on a truly global level drives improved (or at least reflective) health care for all. While a numerical assignment of value according to views, "likes," impressions, or "retweets" may seem meaningless to cynical, established academics, the impetus for universal improvement is self-evident. Electronic data and opinion sharing may not balance the inequity between low- and high-income countries, but it keeps it in perspective. The best way to shift desert sands is to blow on them constantly.

Bacterial production, protozoan grazing, and mineralization in stratified Lake Vechten

NARCIS (Netherlands)

Bloem, J.

1989-01-01

The role of heterotrophic nanoflagellates (HNAN, size 2-20 μm) in grazing on bacteria and mineralization of organic matter in stratified Lake Vechten was studied.

Quantitative effects of manipulation and fixation on HNAN were checked. Considerable losses were caused by

Internal wave patterns in enclosed density-stratified and rotating fluids

NARCIS (Netherlands)

Manders, A.M.A.

2003-01-01

Stratified fluids support internal waves, which propagate obliquely through the fluid. The angle with respectto the stratification direction is contrained: it is purely determined by the wave frequency and the strength of the density stratification (internal gravity waves) or the rotation rate

Computational Fluid Dynamics model of stratified atmospheric boundary-layer flow

DEFF Research Database (Denmark)

Koblitz, Tilman; Bechmann, Andreas; Sogachev, Andrey

2015-01-01

For wind resource assessment, the wind industry is increasingly relying on computational fluid dynamics models of the neutrally stratified surface-layer. So far, physical processes that are important to the whole atmospheric boundary-layer, such as the Coriolis effect, buoyancy forces and heat...

A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

International Nuclear Information System (INIS)

Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok

1995-01-01

This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within ±8%

A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

Energy Technology Data Exchange (ETDEWEB)

Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)] [and others

1995-09-01

This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.

Generation of stratified squamous epithelial progenitor cells from mouse induced pluripotent stem cells.

Directory of Open Access Journals (Sweden)

Satoru Yoshida

Full Text Available BACKGROUND: Application of induced pluripotent stem (iPS cells in regenerative medicine will bypass ethical issues associated with use of embryonic stem cells. In addition, patient-specific IPS cells can be useful to elucidate the pathophysiology of genetic disorders, drug screening, and tailor-made medicine. However, in order to apply iPS cells to mitotic tissue, induction of tissue stem cells that give rise to progeny of the target organ is required. METHODOLOGY/PRINCIPAL FINDINGS: We induced stratified epithelial cells from mouse iPS cells by co-culture with PA6 feeder cells (SDIA-method with use of BMP4. Clusters of cells positive for the differentiation markers KRT1 or KRT12 were observed in KRT14-positive colonies. We successfully cloned KRT14 and p63 double-positive stratified epithelial progenitor cells from iPS-derived epithelial cells, which formed stratified epithelial sheets consisting of five- to six-polarized epithelial cells in vitro. When these clonal cells were cultured on denuded mouse corneas, a robust stratified epithelial layer was observed with physiological cell polarity including high levels of E-cadherin, p63 and K15 expression in the basal layer and ZO-1 in the superficial layer, recapitulating the apico-basal polarity of the epithelium in vivo. CONCLUSIONS/SIGNIFICANCE: These results suggest that KRT14 and p63 double-positive epithelial progenitor cells can be cloned from iPS cells in order to produce polarized multilayer epithelial cell sheets.

Experimental Validation of a Domestic Stratified Hot Water Tank Model in Modelica for Annual Performance Assessment

DEFF Research Database (Denmark)

Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

2015-01-01

The use of stratified hot water tanks in solar energy systems - including ORC systems - as well as heat pump systems is paramount for a better performance of these systems. However, the availability of effective and reliable models to predict the annual performance of stratified hot water tanks...

Safety in online media – freedom of the media; safety of media actors and media education

OpenAIRE

Moeller, Ch

2013-01-01

In this paper, prepared for the international conference ‘Mass Media – Society – Education: Media Safety Problems’ at the Chelyabinsk State University’s Department for Journalism and Media Education from September 30 – October 3, 2013, I would like to address three dimensions of media safety and security in online media.

Theory of hyperbolic stratified nanostructures for surface-enhanced Raman scattering

Science.gov (United States)

Wong, Herman M. K.; Dezfouli, Mohsen Kamandar; Axelrod, Simon; Hughes, Stephen; Helmy, Amr S.

2017-11-01

We theoretically investigate the enhancement of surface enhanced Raman spectroscopy (SERS) using hyperbolic stratified nanostructures and compare to metal nanoresonators. The photon Green function of each nanostructure within its environment is first obtained from a semianalytical modal theory, which is used in a quantum optics formalism of the molecule-nanostructure interaction to model the SERS spectrum. An intuitive methodology is presented for calculating the single-molecule enhancement factor (SMEF), which is also able to predict known experimental SERS enhancement factors of a gold nanodimer. We elucidate the important figures-of-merit of the enhancement and explore these for different designs. We find that the use of hyperbolic stratified materials can enhance the photonic local density of states (LDOS) by close to two times in comparison to pure metal nanostructures, when both designed to work at the same operating wavelengths. However, the increased LDOS is accompanied by higher electric field concentration within the lossy hyperbolic material, which leads to increased quenching that serves to reduce the overall detected SERS enhancement in the far field. For nanoresonators with resonant localized surface plasmon wavelengths in the near-infrared, the SMEF for the hyperbolic stratified nanostructure is approximately one order of magnitude lower than the pure metal counterpart. Conversely, we show that by detecting the Raman signal using a near-field probe, hyperbolic materials can provide an improvement in SERS enhancement compared to using pure metal nanostructures when the probe is sufficiently close (<50 nm ) to the Raman active molecule at the plasmonic hotspot.

Information content of household-stratified epidemics

Directory of Open Access Journals (Sweden)

T.M. Kinyanjui

2016-09-01

Full Text Available Household structure is a key driver of many infectious diseases, as well as a natural target for interventions such as vaccination programs. Many theoretical and conceptual advances on household-stratified epidemic models are relatively recent, but have successfully managed to increase the applicability of such models to practical problems. To be of maximum realism and hence benefit, they require parameterisation from epidemiological data, and while household-stratified final size data has been the traditional source, increasingly time-series infection data from households are becoming available. This paper is concerned with the design of studies aimed at collecting time-series epidemic data in order to maximize the amount of information available to calibrate household models. A design decision involves a trade-off between the number of households to enrol and the sampling frequency. Two commonly used epidemiological study designs are considered: cross-sectional, where different households are sampled at every time point, and cohort, where the same households are followed over the course of the study period. The search for an optimal design uses Bayesian computationally intensive methods to explore the joint parameter-design space combined with the Shannon entropy of the posteriors to estimate the amount of information in each design. For the cross-sectional design, the amount of information increases with the sampling intensity, i.e., the designs with the highest number of time points have the most information. On the other hand, the cohort design often exhibits a trade-off between the number of households sampled and the intensity of follow-up. Our results broadly support the choices made in existing epidemiological data collection studies. Prospective problem-specific use of our computational methods can bring significant benefits in guiding future study designs.

Information content of household-stratified epidemics.

Science.gov (United States)

Kinyanjui, T M; Pellis, L; House, T

2016-09-01

Household structure is a key driver of many infectious diseases, as well as a natural target for interventions such as vaccination programs. Many theoretical and conceptual advances on household-stratified epidemic models are relatively recent, but have successfully managed to increase the applicability of such models to practical problems. To be of maximum realism and hence benefit, they require parameterisation from epidemiological data, and while household-stratified final size data has been the traditional source, increasingly time-series infection data from households are becoming available. This paper is concerned with the design of studies aimed at collecting time-series epidemic data in order to maximize the amount of information available to calibrate household models. A design decision involves a trade-off between the number of households to enrol and the sampling frequency. Two commonly used epidemiological study designs are considered: cross-sectional, where different households are sampled at every time point, and cohort, where the same households are followed over the course of the study period. The search for an optimal design uses Bayesian computationally intensive methods to explore the joint parameter-design space combined with the Shannon entropy of the posteriors to estimate the amount of information in each design. For the cross-sectional design, the amount of information increases with the sampling intensity, i.e., the designs with the highest number of time points have the most information. On the other hand, the cohort design often exhibits a trade-off between the number of households sampled and the intensity of follow-up. Our results broadly support the choices made in existing epidemiological data collection studies. Prospective problem-specific use of our computational methods can bring significant benefits in guiding future study designs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Large Eddy Simulation of stratified flows over structures

OpenAIRE

Brechler J.; Fuka V.

2013-01-01

We tested the ability of the LES model CLMM (Charles University Large-Eddy Microscale Model) to model the stratified flow around three dimensional hills. We compared the quantities, as the height of the dividing streamline, recirculation zone length or length of the lee waves with experiments by Hunt and Snyder[3] and numerical computations by Ding, Calhoun and Street[5]. The results mostly agreed with the references, but some important differences are present.

Large Eddy Simulation of stratified flows over structures

Science.gov (United States)

Fuka, V.; Brechler, J.

2013-04-01

We tested the ability of the LES model CLMM (Charles University Large-Eddy Microscale Model) to model the stratified flow around three dimensional hills. We compared the quantities, as the height of the dividing streamline, recirculation zone length or length of the lee waves with experiments by Hunt and Snyder[3] and numerical computations by Ding, Calhoun and Street[5]. The results mostly agreed with the references, but some important differences are present.

Ecosystem metabolism in a stratified lake

DEFF Research Database (Denmark)

Stæhr, Peter Anton; Christensen, Jesper Philip Aagaard; Batt, Ryan D.

2012-01-01

, differences were not significant. During stratification, daily variability in epilimnetic DO was dominated by metabolism (46%) and air-water gas exchange (44%). Fluxes related to mixed-layer deepening dominated in meta- and hypolimnic waters (49% and 64%), while eddy diffusion (1% and 14%) was less important....... Although air-water gas exchange rates differed among the three formulations of gas-transfer velocity, this had no significant effect on metabolic rates....... that integrates rates across the entire depth profile and includes DO exchange between depth layers driven by mixed-layer deepening and eddy diffusivity. During full mixing, NEP was close to zero throughout the water column, and GPP and R were reduced 2-10 times compared to stratified periods. When present...

Media Literacy in Times of Media Divides

Directory of Open Access Journals (Sweden)

Kaja Žuran

2013-12-01

Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

Economic viability of Stratified Medicine concepts : An investor perspective on drivers and conditions that favour using Stratified Medicine approaches in a cost-contained healthcare environment

NARCIS (Netherlands)

Fugel, Hans-Joerg; Nuijten, Mark; Postma, Maarten

2016-01-01

RATIONALE: Stratified Medicine (SM) is becoming a natural result of advances in biomedical science and a promising path for the innovation-based biopharmaceutical industry to create new investment opportunities. While the use of biomarkers to improve R&D efficiency and productivity is very much

A study of stratified gas-liquid pipe flow

Energy Technology Data Exchange (ETDEWEB)

Johnson, George W.

2005-07-01

This work includes both theoretical modelling and experimental observations which are relevant to the design of gas condensate transport lines. Multicomponent hydrocarbon gas mixtures are transported in pipes over long distances and at various inclinations. Under certain circumstances, the heavier hydrocarbon components and/or water vapour condense to form one or more liquid phases. Near the desired capacity, the liquid condensate and water is efficiently transported in the form of a stratified flow with a droplet field. During operating conditions however, the flow rate may be reduced allowing liquid accumulation which can create serious operational problems due to large amounts of excess liquid being expelled into the receiving facilities during production ramp-up or even in steady production in severe cases. In particular, liquid tends to accumulate in upward inclined sections due to insufficient drag on the liquid from the gas. To optimize the transport of gas condensates, a pipe diameters should be carefully chosen to account for varying flow rates and pressure levels which are determined through the knowledge of the multiphase flow present. It is desirable to have a reliable numerical simulation tool to predict liquid accumulation for various flow rates, pipe diameters and pressure levels which is not presently accounted for by industrial flow codes. A critical feature of the simulation code would include the ability to predict the transition from small liquid accumulation at high flow rates to large liquid accumulation at low flow rates. A semi-intermittent flow regime of roll waves alternating with a partly backward flowing liquid film has been observed experimentally to occur for a range of gas flow rates. Most of the liquid is transported in the roll waves. The roll wave regime is not well understood and requires fundamental modelling and experimental research. The lack of reliable models for this regime leads to inaccurate prediction of the onset of

Experimental analysis of an oblique turbulent flame front propagating in a stratified flow

Energy Technology Data Exchange (ETDEWEB)

Galizzi, C.; Escudie, D. [Universite de Lyon, CNRS, CETHIL, INSA-Lyon, UMR5008, F-69621 Cedex (France)

2010-12-15

This paper details the experimental study of a turbulent V-shaped flame expanding in a nonhomogeneous premixed flow. Its aim is to characterize the effects of stratification on turbulent flame characteristics. The setup consists of a stationary V-shaped flame stabilized on a rod and expanding freely in a lean premixed methane-air flow. One of the two oblique fronts interacts with a stratified slice, which has an equivalence ratio close to one and a thickness greater than that of the flame front. Several techniques such as PIV and CH{sup *} chemiluminescence are used to investigate the instantaneous fields, while laser Doppler anemometry and thermocouples are combined with a concentration probe to provide information on the mean fields. First, in order to provide a reference, the homogeneous turbulent case is studied. Next, the stratified turbulent premixed flame is investigated. Results show significant modifications of the whole flame and of the velocity field upstream of the flame front. The analysis of the geometric properties of the stratified flame indicates an increase in flame brush thickness, closely related to the local equivalence ratio. (author)

Improvements to TRAC models of condensing stratified flow. Pt. 1

International Nuclear Information System (INIS)

Zhang, Q.; Leslie, D.C.

1991-12-01

Direct contact condensation in stratified flow is an important phenomenon in LOCA analyses. In this report, the TRAC interfacial heat transfer model for stratified condensing flow has been assessed against the Bankoff experiments. A rectangular channel option has been added to the code to represent the experimental geometry. In almost all cases the TRAC heat transfer coefficient (HTC) over-predicts the condensation rates and in some cases it is so high that the predicted steam is sucked in from the normal outlet in order to conserve mass. Based on their cocurrent and countercurrent condensing flow experiments, Bankoff and his students (Lim 1981, Kim 1985) developed HTC models from the two cases. The replacement of the TRAC HTC with either of Bankoff's models greatly improves the predictions of condensation rates in the experiment with cocurrent condensing flow. However, the Bankoff HTC for countercurrent flow is preferable because it is based only on the local quantities rather than on the quantities averaged from the inlet. (author)

[Chronic otitis mediaChronic Otitis Media].

Science.gov (United States)

Kohles, N; Schulz, T; Eßer, D

2015-11-01

There are 2 different kinds of chronic otitis media: Otitis media chronica mesotympanalis and otitis media chronica epitympanalis (cholesteatoma). The incidence of chronic otitis media as reported in literature differs in a wide range. The incidence rates vary between 0.45 and 46%. Both, otitis media chronica mesotympanalis and cholesteatoma, lead to eardrum perforation due to lengthy and recurring inflammations. Furthermore, chronic otitis media is characterized by frequently recurring otorrhea and conductive hearing loss. Georg Thieme Verlag KG Stuttgart · New York.

Large Eddy Simulation of stratified flows over structures

Directory of Open Access Journals (Sweden)

Brechler J.

2013-04-01

Full Text Available We tested the ability of the LES model CLMM (Charles University Large-Eddy Microscale Model to model the stratified flow around three dimensional hills. We compared the quantities, as the height of the dividing streamline, recirculation zone length or length of the lee waves with experiments by Hunt and Snyder[3] and numerical computations by Ding, Calhoun and Street[5]. The results mostly agreed with the references, but some important differences are present.

Mixed Convection Flow along a Stretching Cylinder in a Thermally Stratified Medium

Directory of Open Access Journals (Sweden)

Swati Mukhopadhyay

2012-01-01

Full Text Available An analysis for the axisymmetric laminar boundary layer mixed convection flow of a viscous and incompressible fluid towards a stretching cylinder immersed in a thermally stratified medium is presented in this paper. Similarity transformation is employed to convert the governing partial differential equations into highly nonlinear ordinary differential equations. Numerical solutions of these equations are obtained by a shooting method. It is found that the heat transfer rate at the surface is lower for flow in a thermally stratified medium compared to that of an unstratified medium. Moreover, both the skin friction coefficient and the heat transfer rate at the surface are larger for a cylinder compared to that for a flat plate.

Plane Stratified Flow in a Room Ventilated by Displacement Ventilation

DEFF Research Database (Denmark)

Nielsen, Peter Vilhelm; Nickel, J.; Baron, D. J. G.

2004-01-01

The air movement in the occupied zone of a room ventilated by displacement ventilation exists as a stratified flow along the floor. This flow can be radial or plane according to the number of wall-mounted diffusers and the room geometry. The paper addresses the situations where plane flow...

Polarimetric and angular light-scattering from dense media: Comparison of a vectorial radiative transfer model with analytical, stochastic and experimental approaches

International Nuclear Information System (INIS)

Riviere, Nicolas; Ceolato, Romain; Hespel, Laurent

2013-01-01

Our work presents computations via a vectorial radiative transfer model of the polarimetric and angular light scattered by a stratified dense medium with small and intermediate optical thickness. We report the validation of this model using analytical results and different computational methods like stochastic algorithms. Moreover, we check the model with experimental data from a specific scatterometer developed at the Onera. The advantages and disadvantages of a radiative approach are discussed. This paper represents a step toward the characterization of particles in dense media involving multiple scattering. -- Highlights: • A vectorial radiative transfer model to simulate the light scattered by stratified layers is developed. • The vectorial radiative transfer equation is solved using an adding–doubling technique. • The results are compared to analytical and stochastic data. • Validation with experimental data from a scatterometer developed at Onera is presented

White dwarf stars with chemically stratified atmospheres

Science.gov (United States)

Muchmore, D.

1982-01-01

Recent observations and theory suggest that some white dwarfs may have chemically stratified atmospheres - thin layers of hydrogen lying above helium-rich envelopes. Models of such atmospheres show that a discontinuous temperature inversion can occur at the boundary between the layers. Model spectra for layered atmospheres at 30,000 K and 50,000 K tend to have smaller decrements at 912 A, 504 A, and 228 A than uniform atmospheres would have. On the basis of their continuous extreme ultraviolet spectra, it is possible to distinguish observationally between uniform and layered atmospheres for hot white dwarfs.

Measuring mixing efficiency in experiments of strongly stratified turbulence

Science.gov (United States)

Augier, P.; Campagne, A.; Valran, T.; Calpe Linares, M.; Mohanan, A. V.; Micard, D.; Viboud, S.; Segalini, A.; Mordant, N.; Sommeria, J.; Lindborg, E.

2017-12-01

Oceanic and atmospheric models need better parameterization of the mixing efficiency. Therefore, we need to measure this quantity for flows representative of geophysical flows, both in terms of types of flows (with vortices and/or waves) and of dynamical regimes. In order to reach sufficiently large Reynolds number for strongly stratified flows, experiments for which salt is used to produce the stratification have to be carried out in a large rotating platform of at least 10-meter diameter.We present new experiments done in summer 2017 to study experimentally strongly stratified turbulence and mixing efficiency in the Coriolis platform. The flow is forced by a slow periodic movement of an array of large vertical or horizontal cylinders. The velocity field is measured by 3D-2C scanned horizontal particles image velocimetry (PIV) and 2D vertical PIV. Six density-temperature probes are used to measure vertical and horizontal profiles and signals at fixed positions.We will show how we rely heavily on open-science methods for this study. Our new results on the mixing efficiency will be presented and discussed in terms of mixing parameterization.

The dynamics of small inertial particles in weakly stratified turbulence

NARCIS (Netherlands)

van Aartrijk, M.; Clercx, H.J.H.

We present an overview of a numerical study on the small-scale dynamics and the large-scale dispersion of small inertial particles in stably stratified turbulence. Three types of particles are examined: fluid particles, light inertial particles (with particle-to-fluid density ratio 1Ͽp/Ͽf25) and

Hamiltonian approach to the derivation of evolution equations for wave trains in weakly unstable media

Directory of Open Access Journals (Sweden)

N. N. Romanova

1998-01-01

Full Text Available The dynamics of weakly nonlinear wave trains in unstable media is studied. This dynamics is investigated in the framework of a broad class of dynamical systems having a Hamiltonian structure. Two different types of instability are considered. The first one is the instability in a weakly supercritical media. The simplest example of instability of this type is the Kelvin-Helmholtz instability. The second one is the instability due to a weak linear coupling of modes of different nature. The simplest example of a geophysical system where the instability of this and only of this type takes place is the three-layer model of a stratified shear flow with a continuous velocity profile. For both types of instability we obtain nonlinear evolution equations describing the dynamics of wave trains having an unstable spectral interval of wavenumbers. The transformation to appropriate canonical variables turns out to be different for each case, and equations we obtained are different for the two types of instability we considered. Also obtained are evolution equations governing the dynamics of wave trains in weakly subcritical media and in media where modes are coupled in a stable way. Presented results do not depend on a specific physical nature of a medium and refer to a broad class of dynamical systems having the Hamiltonian structure of a special form.

Dipole formation by two interacting shielded monopoles in a stratified fluid

NARCIS (Netherlands)

Beckers, M.; Clercx, H.J.H.; Heijst, van G.J.F.; Verzicco, R.

2002-01-01

The interaction between two shielded monopolar vortices has been investigated experimentally in a nonrotating linearly stratified fluid and by full three-dimensional (3D) numerical simulations. The characteristic Reynolds and Froude numbers in the experiments are approximately Re [[approximate

Numerical simulations of the stratified oceanic bottom boundary layer

Science.gov (United States)

Taylor, John R.

Numerical simulations are used to consider several problems relevant to the turbulent oceanic bottom boundary layer. In the first study, stratified open channel flow is considered with thermal boundary conditions chosen to approximate a shallow sea. Specifically, a constant heat flux is applied at the free surface and the lower wall is assumed to be adiabatic. When the surface heat flux is strong, turbulent upwellings of low speed fluid from near the lower wall are inhibited by the stable stratification. Subsequent studies consider a stratified bottom Ekman layer over a non-sloping lower wall. The influence of the free surface is removed by using an open boundary condition at the top of the computational domain. Particular attention is paid to the influence of the outer layer stratification on the boundary layer structure. When the density field is initialized with a linear profile, a turbulent mixed layer forms near the wall, which is separated from the outer layer by a strongly stable pycnocline. It is found that the bottom stress is not strongly affected by the outer layer stratification. However, stratification reduces turbulent transport to the outer layer and strongly limits the boundary layer height. The mean shear at the top of the boundary layer is enhanced when the outer layer is stratified, and this shear is strong enough to cause intermittent instabilities above the pycnocline. Turbulence-generated internal gravity waves are observed in the outer layer with a relatively narrow frequency range. An explanation for frequency content of these waves is proposed, starting with an observed broad-banded turbulent spectrum and invoking linear viscous decay to explain the preferential damping of low and high frequency waves. During the course of this work, an open-source computational fluid dynamics code has been developed with a number of advanced features including scalar advection, subgrid-scale models for large-eddy simulation, and distributed memory

Perilaku Asertif dan Kecenderungan Kenakalan Remaja Berdasarkan Pola Asuh dan Peran Media Massa

Directory of Open Access Journals (Sweden)

- Sriyanto

2014-06-01

Full Text Available Theoretically the adolescent psychological development is a transition period which is marked by changes in biological, psychological and social aspects. Empirically, the increasing trend of juvenile delinquency is caused by the inability of the early adolescents to be assertive so that their personality become weak and they can easily fall into negative things. This study aimed at determining the extent to which environment and mass media have the influence on assertive behaviour and juvenile delinquency trend in Junior High School in West Java Province. The respondents of this research were 458 students of Junior High Schools in West Java. Questionnaire was used to collect the data. Samples were chosen by using stratified random sampling technique. Data analysis employed Structural Equation Modelling (SEM with two-stages testing: measurement model and structural model, using Analysis of Moment Structure (AMOS. The results of this study revealed that all hypothetical statements have significant effects. The findings showed that the increasing level of students’ assertive behaviour can decrease the tendency of juvenile delinquency in them. Keywords: assertive behaviour, parenting, mass media, juvenile delinquency trend

Stratified sampling design based on data mining.

Science.gov (United States)

Kim, Yeonkook J; Oh, Yoonhwan; Park, Sunghoon; Cho, Sungzoon; Park, Hayoung

2013-09-01

To explore classification rules based on data mining methodologies which are to be used in defining strata in stratified sampling of healthcare providers with improved sampling efficiency. We performed k-means clustering to group providers with similar characteristics, then, constructed decision trees on cluster labels to generate stratification rules. We assessed the variance explained by the stratification proposed in this study and by conventional stratification to evaluate the performance of the sampling design. We constructed a study database from health insurance claims data and providers' profile data made available to this study by the Health Insurance Review and Assessment Service of South Korea, and population data from Statistics Korea. From our database, we used the data for single specialty clinics or hospitals in two specialties, general surgery and ophthalmology, for the year 2011 in this study. Data mining resulted in five strata in general surgery with two stratification variables, the number of inpatients per specialist and population density of provider location, and five strata in ophthalmology with two stratification variables, the number of inpatients per specialist and number of beds. The percentages of variance in annual changes in the productivity of specialists explained by the stratification in general surgery and ophthalmology were 22% and 8%, respectively, whereas conventional stratification by the type of provider location and number of beds explained 2% and 0.2% of variance, respectively. This study demonstrated that data mining methods can be used in designing efficient stratified sampling with variables readily available to the insurer and government; it offers an alternative to the existing stratification method that is widely used in healthcare provider surveys in South Korea.

Direct contact condensation induced transition from stratified to slug flow

International Nuclear Information System (INIS)

Strubelj, Luka; Ezsoel, Gyoergy; Tiselj, Iztok

2010-01-01

Selected condensation-induced water hammer experiments performed on PMK-2 device were numerically modelled with three-dimensional two-fluid models of computer codes NEPTUNE C FD and CFX. Experimental setup consists of the horizontal pipe filled with the hot steam that is being slowly flooded with cold water. In most of the experimental cases, slow flooding of the pipe was abruptly interrupted by a strong slugging and water hammer, while in the selected experimental runs performed at higher initial pressures and temperatures that are analysed in the present work, the transition from the stratified into the slug flow was not accompanied by the water hammer pressure peak. That makes these cases more suitable tests for evaluation of the various condensation models in the horizontally stratified flows and puts them in the range of the available CFD (Computational Fluid Dynamics) codes. The key models for successful simulation appear to be the condensation model of the hot vapour on the cold liquid and the interfacial momentum transfer model. The surface renewal types of condensation correlations, developed for condensation in the stratified flows, were used in the simulations and were applied also in the regions of the slug flow. The 'large interface' model for inter-phase momentum transfer model was compared to the bubble drag model. The CFD simulations quantitatively captured the main phenomena of the experiments, while the stochastic nature of the particular condensation-induced water hammer experiments did not allow detailed prediction of the time and position of the slug formation in the pipe. We have clearly shown that even the selected experiments without water hammer present a tough test for the applied CFD codes, while modelling of the water hammer pressure peaks in two-phase flow, being a strongly compressible flow phenomena, is beyond the capability of the current CFD codes.

Proposed catalog of the neuroanatomy and the stratified anatomy for the 361 acupuncture points of 14 channels.

Science.gov (United States)

Chapple, Will

2013-10-01

In spite of the extensive research on acupuncture mechanisms, no comprehensive and systematic peer-reviewed reference list of the stratified anatomical and the neuroanatomical features of all 361 acupuncture points exists. This study creates a reference list of the neuroanatomy and the stratified anatomy for each of the 361 acupuncture points on the 14 classical channels and for 34 extra points. Each acupuncture point was individually assessed to relate the point's location to anatomical and neuroanatomical features. The design of the catalogue is intended to be useful for any style of acupuncture or Oriental medicine treatment modality. The stratified anatomy was divided into shallow, intermediate and deep insertion. A separate stratified anatomy was presented for different needle angles and directions. The following are identified for each point: additional specifications for point location, the stratified anatomy, motor innervation, cutaneous nerve and sensory innervation, dermatomes, Langer's lines, and somatotopic organization in the primary sensory and motor cortices. Acupuncture points for each muscle, dermatome and myotome are also reported. This reference list can aid clinicians, practitioners and researchers in furthering the understanding and accurate practice of acupuncture. Additional research on the anatomical variability around acupuncture points, the frequency of needle contact with an anatomical structure in a clinical setting, and conformational imaging should be done to verify this catalogue. Copyright © 2013. Published by Elsevier B.V.

Managing Media: Segmenting Media Through Consumer Expectancies

Directory of Open Access Journals (Sweden)

Matt Eastin

2014-04-01

Full Text Available It has long been understood that consumers are motivated to media differently. However, given the lack of comparative model analysis, this assumption is without empirical validation, and thus, the orientation of segmentation from a media management perspective is without motivational grounds. Thus, evolving the literature on media consumption, the current study develops and compares models of media segmentation within the context of use. From this study, six models of media expectancies were constructed so that motivational differences between media (i.e., local and national newspapers, network and cable television, radio, and Internet could be observed. Utilizing higher order statistical analyses the data indicates differences across a model comparison approach for media motivations. Furthermore, these differences vary across numerous demographic factors. Results afford theoretical advancement within the literature of consumer media consumption as well as provide media planners’ insight into consumer choices.

Bayesian stratified sampling to assess corpus utility

Energy Technology Data Exchange (ETDEWEB)

Hochberg, J.; Scovel, C.; Thomas, T.; Hall, S.

1998-12-01

This paper describes a method for asking statistical questions about a large text corpus. The authors exemplify the method by addressing the question, ``What percentage of Federal Register documents are real documents, of possible interest to a text researcher or analyst?`` They estimate an answer to this question by evaluating 200 documents selected from a corpus of 45,820 Federal Register documents. Bayesian analysis and stratified sampling are used to reduce the sampling uncertainty of the estimate from over 3,100 documents to fewer than 1,000. A possible application of the method is to establish baseline statistics used to estimate recall rates for information retrieval systems.

Stratified turbulent Bunsen flames: flame surface analysis and flame surface density modelling

Science.gov (United States)

Ramaekers, W. J. S.; van Oijen, J. A.; de Goey, L. P. H.

2012-12-01

In this paper it is investigated whether the Flame Surface Density (FSD) model, developed for turbulent premixed combustion, is also applicable to stratified flames. Direct Numerical Simulations (DNS) of turbulent stratified Bunsen flames have been carried out, using the Flamelet Generated Manifold (FGM) reduction method for reaction kinetics. Before examining the suitability of the FSD model, flame surfaces are characterized in terms of thickness, curvature and stratification. All flames are in the Thin Reaction Zones regime, and the maximum equivalence ratio range covers 0.1⩽φ⩽1.3. For all flames, local flame thicknesses correspond very well to those observed in stretchless, steady premixed flamelets. Extracted curvature radii and mixing length scales are significantly larger than the flame thickness, implying that the stratified flames all burn in a premixed mode. The remaining challenge is accounting for the large variation in (subfilter) mass burning rate. In this contribution, the FSD model is proven to be applicable for Large Eddy Simulations (LES) of stratified flames for the equivalence ratio range 0.1⩽φ⩽1.3. Subfilter mass burning rate variations are taken into account by a subfilter Probability Density Function (PDF) for the mixture fraction, on which the mass burning rate directly depends. A priori analysis point out that for small stratifications (0.4⩽φ⩽1.0), the replacement of the subfilter PDF (obtained from DNS data) by the corresponding Dirac function is appropriate. Integration of the Dirac function with the mass burning rate m=m(φ), can then adequately model the filtered mass burning rate obtained from filtered DNS data. For a larger stratification (0.1⩽φ⩽1.3), and filter widths up to ten flame thicknesses, a β-function for the subfilter PDF yields substantially better predictions than a Dirac function. Finally, inclusion of a simple algebraic model for the FSD resulted only in small additional deviations from DNS data

Interfacial transport characteristics in a gas-liquid or an immiscible liquid-liquid stratified flow

International Nuclear Information System (INIS)

Inoue, A.; Aoki, S.; Aritomi, M.; Kozawa, Y.

1982-01-01

This paper is a review for an interfacial transport characteristics of mass, momentum and energy in a gas-liquid or a immiscible liquid-liquid stratified flow with wavy interface which have been studied in our division. In the experiment, a characteristic of wave motion and its effect to the turbulence near the interface as well as overall flow characteristics like pressure drop, position of the interface were investigated in an air-water, an air-mercury and a water-liquid metal stratified flow. On the other hand, several models based on the mixing length model and a two-equation model of turbulence, with special interfacial boundary conditions in which the wavy surface was regarded as a rough surface correspond to the wavy height, a source of turbulent energy equal to the wave energy and a damped-turbulence due to the surface tension, were proposed to predict the flow characteristics and the interfacial heat transfer in a fully developed and an undeveloped stratified flow and examined by the experimental data. (author)

LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES

Energy Technology Data Exchange (ETDEWEB)

Luna-Cardozo, M. [Instituto de Astronomia y Fisica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Verth, G. [School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST (United Kingdom); Erdelyi, R., E-mail: mluna@iafe.uba.ar, E-mail: robertus@sheffield.ac.uk, E-mail: gary.verth@northumbria.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2012-04-01

Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

Random forcing of geostrophic motion in rotating stratified turbulence

Science.gov (United States)

Waite, Michael L.

2017-12-01

Random forcing of geostrophic motion is a common approach in idealized simulations of rotating stratified turbulence. Such forcing represents the injection of energy into large-scale balanced motion, and the resulting breakdown of quasi-geostrophic turbulence into inertia-gravity waves and stratified turbulence can shed light on the turbulent cascade processes of the atmospheric mesoscale. White noise forcing is commonly employed, which excites all frequencies equally, including frequencies much higher than the natural frequencies of large-scale vortices. In this paper, the effects of these high frequencies in the forcing are investigated. Geostrophic motion is randomly forced with red noise over a range of decorrelation time scales τ, from a few time steps to twice the large-scale vortex time scale. It is found that short τ (i.e., nearly white noise) results in about 46% more gravity wave energy than longer τ, despite the fact that waves are not directly forced. We argue that this effect is due to wave-vortex interactions, through which the high frequencies in the forcing are able to excite waves at their natural frequencies. It is concluded that white noise forcing should be avoided, even if it is only applied to the geostrophic motion, when a careful investigation of spontaneous wave generation is needed.

Optimal energy growth in a stably stratified shear flow

Science.gov (United States)

Jose, Sharath; Roy, Anubhab; Bale, Rahul; Iyer, Krithika; Govindarajan, Rama

2018-02-01

Transient growth of perturbations by a linear non-modal evolution is studied here in a stably stratified bounded Couette flow. The density stratification is linear. Classical inviscid stability theory states that a parallel shear flow is stable to exponentially growing disturbances if the Richardson number (Ri) is greater than 1/4 everywhere in the flow. Experiments and numerical simulations at higher Ri show however that algebraically growing disturbances can lead to transient amplification. The complexity of a stably stratified shear flow stems from its ability to combine this transient amplification with propagating internal gravity waves (IGWs). The optimal perturbations associated with maximum energy amplification are numerically obtained at intermediate Reynolds numbers. It is shown that in this wall-bounded flow, the three-dimensional optimal perturbations are oblique, unlike in unstratified flow. A partitioning of energy into kinetic and potential helps in understanding the exchange of energies and how it modifies the transient growth. We show that the apportionment between potential and kinetic energy depends, in an interesting manner, on the Richardson number, and on time, as the transient growth proceeds from an optimal perturbation. The oft-quoted stabilizing role of stratification is also probed in the non-diffusive limit in the context of disturbance energy amplification.

Media relations after the introduction of social media

OpenAIRE

Mesila, Helin

2010-01-01

In the light of the popularity of social media on one hand, and the contradictive relationships between journalists and public relations practitioners on the other hand, the thesis studies media relations after the introduction of social media. The study focuses on media relations in Estonian public relations scenery. The research answers to the questions: - What are media relations today? - What are the functions of social media and media relations in organizational communication? ...

Technetium reduction and removal in a stratified fjord

International Nuclear Information System (INIS)

Keith-Roach, M.; Roos, P.

2002-01-01

The distribution of Tc in the water columns of a stratified fjord has been measured to investigate the behaviour and fate of Tc on reaching reducing waters. Slow mixing in the water column of the fjord results in vertical transport of the dissolved Tc to the oxic/anoxic interface. Tc is reduced just below the interface and at 21 m 60% is sorbed to particulate and colloidal material. Tc is carried to the sediments sorbed to the particulate material, where there is a current inventory of approximately 3 Bq m -2 . (LN)

Technetium reduction and removal in a stratified fjord

Energy Technology Data Exchange (ETDEWEB)

Keith-Roach, M.; Roos, P. [Risoe National Lab., Roskilde (Denmark)

2002-04-01

The distribution of Tc in the water columns of a stratified fjord has been measured to investigate the behaviour and fate of Tc on reaching reducing waters. Slow mixing in the water column of the fjord results in vertical transport of the dissolved Tc to the oxic/anoxic interface. Tc is reduced just below the interface and at 21 m 60% is sorbed to particulate and colloidal material. Tc is carried to the sediments sorbed to the particulate material, where there is a current inventory of approximately 3 Bq m{sup -2}. (LN)

Sensitivity of the Geomagnetic Octupole to a Stably Stratified Layer in the Earth's Core

Science.gov (United States)

Yan, C.; Stanley, S.

2017-12-01

The presence of a stably stratified layer at the top of the core has long been proposed for Earth, based on evidence from seismology and geomagnetic secular variation. Geodynamo modeling offers a unique window to inspect the properties and dynamics in Earth's core. For example, numerical simulations have shown that magnetic field morphology is sensitive to the presence of stably stratified layers in a planet's core. Here we use the mMoSST numerical dynamo model to investigate the effects of a thin stably stratified layer at the top of the fluid outer core in Earth on the resulting large-scale geomagnetic field morphology. We find that the existence of a stable layer has significant influence on the octupolar component of the magnetic field in our models, whereas the quadrupole doesn't show an obvious trend. This suggests that observations of the geomagnetic field can be applied to provide information of the properties of this plausible stable layer, such as how thick and how stable this layer could be. Furthermore, we have examined whether the dominant thermal signature from mantle tomography at the core-mantle boundary (CMB) (a degree & order 2 spherical harmonic) can influence our results. We found that this heat flux pattern at the CMB has no outstanding effects on the quadrupole and octupole magnetic field components. Our studies suggest that if there is a stably stratified layer at the top of the Earth's core, it must be limited in terms of stability and thickness, in order to be compatible with the observed paleomagnetic record.

Does neighbourhood walkability moderate the effects of mass media communication strategies to promote regular physical activity?

Science.gov (United States)

Barnes, R; Giles-Corti, B; Bauman, A; Rosenberg, M; Bull, F C; Leavy, J E

2013-02-01

Mass media campaigns are widely used in Australia and elsewhere to promote physical activity among adults. Neighbourhood walkability is consistently shown to be associated with walking and total activity. Campaigns may have different effects on individuals living in high and low walkable neighbourhoods. The purpose of this study is to compare pre- and post-campaign cognitive and behavioural impacts of the Heart Foundation's Find Thirty every day® campaign, in respondents living in high and lower walkable neighbourhoods. Pre- and post-campaign cross-sectional survey data were linked with objectively measured neighbourhood walkability. Cognitive and behavioural impacts were assessed using logistic regression stratified by walkability. Cognitive impacts were significantly higher post-campaign and consistently higher in respondents in high compared with lower walkable neighbourhoods. Post campaign sufficient activity was significantly higher and transport walking significantly lower, but only in residents of lower walkable areas. Cognitive impacts of mass media physical activity campaigns may be enhanced by living in a more walkable neighbourhood.

Propagation of acoustic waves in a stratified atmosphere, 1

Science.gov (United States)

Kalkofen, W.; Rossi, P.; Bodo, G.; Massaglia, S.

1994-01-01

This work is motivated by the chromospheric 3 minute oscillations observed in the K(sub 2v) bright points. We study acoustic gravity waves in a one-dimensional, gravitationally stratified, isothermal atmosphere. The oscillations are excited either by a velocity pulse imparted to a layer in an atmosphere of infinite vertical extent, or by a piston forming the lower boundary of a semi-infinite medium. We consider both linear and non-linear waves.

Stratified polymer brushes from microcontact printing of polydopamine initiator on polymer brush surfaces.

Science.gov (United States)

Wei, Qiangbing; Yu, Bo; Wang, Xiaolong; Zhou, Feng

2014-06-01

Stratified polymer brushes are fabricated using microcontact printing (μCP) of initiator integrated polydopamine (PDOPBr) on polymer brush surfaces and the following surface initiated atom transfer radical polymerization (SI-ATRP). It is found that the surface energy, chemically active groups, and the antifouling ability of the polymer brushes affect transfer efficiency and adhesive stability of the polydopamine film. The stickiness of the PDOPBr pattern on polymer brush surfaces is stable enough to perform continuous μCP and SI-ATRP to prepare stratified polymer brushes with a 3D topography, which have broad applications in cell and protein patterning, biosensors, and hybrid surfaces. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emerging Techniques in Stratified Designs and Continuous Gradients for Tissue Engineering of Interfaces

Science.gov (United States)

Dormer, Nathan H.; Berkland, Cory J.; Detamore, Michael S.

2013-01-01

Interfacial tissue engineering is an emerging branch of regenerative medicine, where engineers are faced with developing methods for the repair of one or many functional tissue systems simultaneously. Early and recent solutions for complex tissue formation have utilized stratified designs, where scaffold formulations are segregated into two or more layers, with discrete changes in physical or chemical properties, mimicking a corresponding number of interfacing tissue types. This method has brought forth promising results, along with a myriad of regenerative techniques. The latest designs, however, are employing “continuous gradients” in properties, where there is no discrete segregation between scaffold layers. This review compares the methods and applications of recent stratified approaches to emerging continuously graded methods. PMID:20411333

Multi-Instrument Observations of Prolonged Stratified Wind Layers at Iqaluit, Nunavut

Science.gov (United States)

Mariani, Zen; Dehghan, Armin; Gascon, Gabrielle; Joe, Paul; Hudak, David; Strawbridge, Kevin; Corriveau, Julien

2018-02-01

Data collected between October 2015 and May 2016 at Environment and Climate Change Canada's Iqaluit research site (64°N, 69°W) have revealed a high frequency (40% of all days for which observations were available) of stratified wind layer events that occur from near the surface up to about 7.2 km above sea level. These stratified wind layers are clearly visible as wind shifts (90 to 180°) with height in range-height indicator scans from the Doppler lidar and Ka-band radar and in wind direction profiles from the Doppler lidar and radiosonde. During these events, the vertical structure of the flow appears to be a stack of 4 to 10 layers ranging in vertical width from 0.1 to 4.4 km. The stratification events that were observed occurred predominantly (81%) during light precipitation and lasted up to 27.5 h. The integrated measurement platforms at Iqaluit permitted continuous observations of the evolution of stratification events in different meteorological conditions.

The stratified Boycott effect

Science.gov (United States)

Peacock, Tom; Blanchette, Francois; Bush, John W. M.

2005-04-01

We present the results of an experimental investigation of the flows generated by monodisperse particles settling at low Reynolds number in a stably stratified ambient with an inclined sidewall. In this configuration, upwelling beneath the inclined wall associated with the Boycott effect is opposed by the ambient density stratification. The evolution of the system is determined by the relative magnitudes of the container depth, h, and the neutral buoyancy height, hn = c0(ρp-ρf)/|dρ/dz|, where c0 is the particle concentration, ρp the particle density, ρf the mean fluid density and dρ/dz Boycott layer transports dense fluid from the bottom to the top of the system; subsequently, the upper clear layer of dense saline fluid is mixed by convection. For sufficiently strong stratification, h > hn, layering occurs. The lowermost layer is created by clear fluid transported from the base to its neutral buoyancy height, and has a vertical extent hn; subsequently, smaller overlying layers develop. Within each layer, convection erodes the initially linear density gradient, generating a step-like density profile throughout the system that persists after all the particles have settled. Particles are transported across the discrete density jumps between layers by plumes of particle-laden fluid.

SOCIAL MEDIA

Science.gov (United States)

RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeMEDIASOCIAL MEDIA Social Media CENTCOM'S ENGLISH SOCIAL MEDIA ACCOUNTS There are many U.S. military commands

Indications for tonsillectomy stratified by the level of evidence

Science.gov (United States)

Windfuhr, Jochen P.

2016-01-01

Background: One of the most significant clinical trials, demonstrating the efficacy of tonsillectomy (TE) for recurrent throat infection in severely affected children, was published in 1984. This systematic review was undertaken to compile various indications for TE as suggested in the literature after 1984 and to stratify the papers according to the current concept of evidence-based medicine. Material and methods: A systematic Medline research was performed using the key word of “tonsillectomy“ in combination with different filters such as “systematic reviews“, “meta-analysis“, “English“, “German“, and “from 1984/01/01 to 2015/05/31“. Further research was performed in the Cochrane Database of Systematic Reviews, National Guideline Clearinghouse, Guidelines International Network and BMJ Clinical Evidence using the same key word. Finally, data from the “Trip Database” were researched for “tonsillectomy” and “indication“ and “from: 1984 to: 2015“ in combination with either “systematic review“ or “meta-analysis“ or “metaanalysis”. Results: A total of 237 papers were retrieved but only 57 matched our inclusion criteria covering the following topics: peritonsillar abscess (3), guidelines (5), otitis media with effusion (5), psoriasis (3), PFAPA syndrome (6), evidence-based indications (5), renal diseases (7), sleep-related breathing disorders (11), and tonsillitis/pharyngitis (12), respectively. Conclusions: 1) The literature suggests, that TE is not indicated to treat otitis media with effusion. 2) It has been shown, that the PFAPA syndrome is self-limiting and responds well to steroid administration, at least in a considerable amount of children. The indication for TE therefore appears to be imbalanced but further research is required to clarify the value of surgery. 3) Abscesstonsillectomy as a routine is not justified and indicated only for cases not responding to other measures of treatment, evident complications

Implementing risk-stratified screening for common cancers: a review of potential ethical, legal and social issues.

Science.gov (United States)

Hall, A E; Chowdhury, S; Hallowell, N; Pashayan, N; Dent, T; Pharoah, P; Burton, H

2014-06-01

The identification of common genetic variants associated with common cancers including breast, prostate and ovarian cancers would allow population stratification by genotype to effectively target screening and treatment. As scientific, clinical and economic evidence mounts there will be increasing pressure for risk-stratified screening programmes to be implemented. This paper reviews some of the main ethical, legal and social issues (ELSI) raised by the introduction of genotyping into risk-stratified screening programmes, in terms of Beauchamp and Childress's four principles of biomedical ethics--respect for autonomy, non-maleficence, beneficence and justice. Two alternative approaches to data collection, storage, communication and consent are used to exemplify the ELSI issues that are likely to be raised. Ultimately, the provision of risk-stratified screening using genotyping raises fundamental questions about respective roles of individuals, healthcare providers and the state in organizing or mandating such programmes, and the principles, which underpin their provision, particularly the requirement for distributive justice. The scope and breadth of these issues suggest that ELSI relating to risk-stratified screening will become increasingly important for policy-makers, healthcare professionals and a wide diversity of stakeholders. © The Author 2013. Published by Oxford University Press on behalf of Faculty of Public Health.

Evaluation of a Stratified National Breast Screening Program in the United Kingdom: An Early Model-Based Cost-Effectiveness Analysis.

Science.gov (United States)

Gray, Ewan; Donten, Anna; Karssemeijer, Nico; van Gils, Carla; Evans, D Gareth; Astley, Sue; Payne, Katherine

2017-09-01

To identify the incremental costs and consequences of stratified national breast screening programs (stratified NBSPs) and drivers of relative cost-effectiveness. A decision-analytic model (discrete event simulation) was conceptualized to represent four stratified NBSPs (risk 1, risk 2, masking [supplemental screening for women with higher breast density], and masking and risk 1) compared with the current UK NBSP and no screening. The model assumed a lifetime horizon, the health service perspective to identify costs (£, 2015), and measured consequences in quality-adjusted life-years (QALYs). Multiple data sources were used: systematic reviews of effectiveness and utility, published studies reporting costs, and cohort studies embedded in existing NBSPs. Model parameter uncertainty was assessed using probabilistic sensitivity analysis and one-way sensitivity analysis. The base-case analysis, supported by probabilistic sensitivity analysis, suggested that the risk stratified NBSPs (risk 1 and risk-2) were relatively cost-effective when compared with the current UK NBSP, with incremental cost-effectiveness ratios of £16,689 per QALY and £23,924 per QALY, respectively. Stratified NBSP including masking approaches (supplemental screening for women with higher breast density) was not a cost-effective alternative, with incremental cost-effectiveness ratios of £212,947 per QALY (masking) and £75,254 per QALY (risk 1 and masking). When compared with no screening, all stratified NBSPs could be considered cost-effective. Key drivers of cost-effectiveness were discount rate, natural history model parameters, mammographic sensitivity, and biopsy rates for recalled cases. A key assumption was that the risk model used in the stratification process was perfectly calibrated to the population. This early model-based cost-effectiveness analysis provides indicative evidence for decision makers to understand the key drivers of costs and QALYs for exemplar stratified NBSP. Copyright

Stratified growth in Pseudomonas aeruginosa biofilms

DEFF Research Database (Denmark)

Werner, E.; Roe, F.; Bugnicourt, A.

2004-01-01

In this study, stratified patterns of protein synthesis and growth were demonstrated in Pseudomonas aeruginosa biofilms. Spatial patterns of protein synthetic activity inside biofilms were characterized by the use of two green fluorescent protein (GFP) reporter gene constructs. One construct...... synthesis was restricted to a narrow band in the part of the biofilm adjacent to the source of oxygen. The zone of active GFP expression was approximately 60 Am wide in colony biofilms and 30 Am wide in flow cell biofilms. The region of the biofilm in which cells were capable of elongation was mapped...... by treating colony biofilms with carbenicillin, which blocks cell division, and then measuring individual cell lengths by transmission electron microscopy. Cell elongation was localized at the air interface of the biofilm. The heterogeneous anabolic patterns measured inside these biofilms were likely a result...

Thermal instability in a stratified plasma

International Nuclear Information System (INIS)

Hermanns, D.F.M.; Priest, E.R.

1989-01-01

The thermal instability mechansism has been studied in connection to observed coronal features, like, e.g. prominences or cool cores in loops. Although these features show a lot of structure, most studies concern the thermal instability in an uniform medium. In this paper, we investigate the thermal instability and the interaction between thermal modes and the slow magneto-acoustic subspectrum for a stratified plasma slab. We fomulate the relevant system of equations and give some straightforward properties of the linear spectrum of a non-uniform plasma slab, i.e. the existence of continuous parts in the spectrum. We present a numerical scheme with which we can investigate the linear spectrum for equilibrium states with stratification. The slow and thermal subspectra of a crude coronal model are given as a preliminary result. (author). 6 refs.; 1 fig

The effect of sediments on turbulent plume dynamics in a stratified fluid

Science.gov (United States)

Stenberg, Erik; Ezhova, Ekaterina; Brandt, Luca

2017-11-01

We report large eddy simulation results of sediment-loaded turbulent plumes in a stratified fluid. The configuration, where the plume is discharged from a round source, provides an idealized model of subglacial discharge from a submarine tidewater glacier and is a starting point for understanding the effect of sediments on the dynamics of the rising plume. The transport of sediments is modeled by means of an advection-diffusion equation where sediment settling velocity is taken into account. We initially follow the experimental setup of Sutherland (Phys. Rev. Fluids, 2016), considering uniformly stratified ambients and further extend the work to pycnocline-type stratifications typical of Greenland fjords. Apart from examining the rise height, radial spread and intrusion of the rising plume, we gain further insights of the plume dynamics by extracting turbulent characteristics and the distribution of the sediments inside the plume.

A statistical mechanics approach to mixing in stratified fluids

OpenAIRE

Venaille , Antoine; Gostiaux , Louis; Sommeria , Joël

2016-01-01

Accepted for the Journal of Fluid Mechanics; Predicting how much mixing occurs when a given amount of energy is injected into a Boussinesq fluid is a longstanding problem in stratified turbulence. The huge number of degrees of freedom involved in these processes renders extremely difficult a deterministic approach to the problem. Here we present a statistical mechanics approach yielding a prediction for a cumulative, global mixing efficiency as a function of a global Richard-son number and th...

Sutudy on exchange flow under the unstably stratified field

OpenAIRE

文沢, 元雄

2005-01-01

This paper deals with the exchange flow under the unstably stratified field. The author developed the effective measurement system as well as the numerical analysis program. The system and the program are applied to the helium-air exchange flow in a rectangular channel with inclination. Following main features of the exchange flow were discussed based on the calculated results.(1) Time required for establishing a quasi-steady state exchange flow.(2) The relationship between the inclination an...

A study on the instability criterion for the stratified flow in horizontal pipe at cocurrent flow conditions

Energy Technology Data Exchange (ETDEWEB)

Sung, Chang Kyung [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

1998-12-31

This paper presents a theoretical approach of the instability criterion from stratified to nonstratified flow in horizontal pipe at cocurrent flow conditions. The new theoretical instability criterion for the stratified and nonstratified flow transition in horizontal pipe has been developed by hyperbolic equations in two-phase flow. Critical flow condition criterion and onset of slugging at cocurrent flow condition correspond to zero and imaginary characteristics which occur when the hyperbolicity of a stratified two-phase flow is broken, respectively. Through comparison between results predicted by the present flow is broken, respectively. Through comparison between results predicted by the present theory and the Kukita et al. [1] experimental data of pipes, it is shown that they are in good agreement with data. 4 refs., 2 figs. (Author)

A study on the instability criterion for the stratified flow in horizontal pipe at cocurrent flow conditions

Energy Technology Data Exchange (ETDEWEB)

Sung, Chang Kyung [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

1997-12-31

This paper presents a theoretical approach of the instability criterion from stratified to nonstratified flow in horizontal pipe at cocurrent flow conditions. The new theoretical instability criterion for the stratified and nonstratified flow transition in horizontal pipe has been developed by hyperbolic equations in two-phase flow. Critical flow condition criterion and onset of slugging at cocurrent flow condition correspond to zero and imaginary characteristics which occur when the hyperbolicity of a stratified two-phase flow is broken, respectively. Through comparison between results predicted by the present flow is broken, respectively. Through comparison between results predicted by the present theory and the Kukita et al. [1] experimental data of pipes, it is shown that they are in good agreement with data. 4 refs., 2 figs. (Author)

CLASSICAL MEDIA RELATIONS AND NEW MEDIA RELATIONS IN SPORT

Directory of Open Access Journals (Sweden)

Alexandru Lucian MIHAI

2014-06-01

Full Text Available Media relations in sport mean maintenance of networks and positive relationships with people in the media to obtain positive media exposure for a sport product (informal and formal information sessions with media representatives. Because of the pervasive influence the media has on marketing success, sport marketers must make concerted efforts to create a positive relationship between their sport event and the media. They may accomplish this by providing the media with press releases, having news conferences, having media-day events (in which the media are invited to interact with the players, coaches, and administrators, providing media guides for the respective sport events and so on. Each of these activities promotes active involvement from the media, which will subsequently contribute to relationship building with the community.

Gender Stratified Monopoly: Why Do I Earn Less and Pay More?

Science.gov (United States)

Smith, Stacy L.

2017-01-01

A modified version of Monopoly has long been used as a simulation exercise to teach inequality. Versions of Modified Monopoly (MM) have touched on minority status relative to inequality but without an exploration of the complex interaction between minority status and class. This article introduces Gender Stratified Monopoly (GSM), an adaptation…

MHD Kelvin-Helmholtz instability in non-hydrostatic equilibrium

International Nuclear Information System (INIS)

Laghouati, Y; Bouabdallah, A; Zizi, M; Alemany, A

2007-01-01

The present work deals with the linear stability of a magnetohydrodynamic shear flow so that a stratified inviscid fluid rotating about a vertical axis when a uniform magnetic field is applied in the direction of the streaming or zonal flow. In geophysical flow, the stability of the flow is determined by taking into account the nonhydrostatic condition depending on Richardson number R i and the deviation δ from hydrostatic equilibrium. According to Stone (Stone P H 1971 J. Fluid. Mech. 45 659), it is shown that such deviation δ decreases the growth rates of three kinds of instability which can appear as geostrophic (G), symmetric (S) and Kelvin-Helmholtz (K-H) instabilities. To be specific, the evolution of the flow is therefore considered in the light of the influence of magnetic field, particularly, on K-H instability. The results of this study are presented by the linear stability of a magnetohydrodynamic, with horizontal free-shear flow of stratified fluid, subject to rotation about the vertical axis and uniform magnetic field in the zonal direction. Results are discussed and compared to previous works as Chandrasekhar (Chandrasekhar S 1961 Hydrodynamic and hydromagnetic stability (Oxford: Clarendon Press) chapter 11 pp 481-513) and Stone

Media education and media influence on youth

OpenAIRE

LILÁK, Karel

2011-01-01

Bachelor´s work is focused on the questions of the medial education and the medias themselves. This work also investigate with the influence of the action of medias to the students of apprenticeship. The first part of the theoretical work has generally explains what is media education, what is its significance for society and for the benefit of education in school. They are given functions, types and objectives of media education and communications capabilities via the media. The second part ...

Longevity of Compositionally Stratified Layers in Ice Giants

Science.gov (United States)

Friedson, A. J.

2017-12-01

In the hydrogen-rich atmospheres of gas giants, a decrease with radius in the mixing ratio of a heavy species (e.g. He, CH4, H2O) has the potential to produce a density stratification that is convectively stable if the heavy species is sufficiently abundant. Formation of stable layers in the interiors of these planets has important implications for their internal structure, chemical mixing, dynamics, and thermal evolution, since vertical transport of heat and constituents in such layers is greatly reduced in comparison to that in convecting layers. Various processes have been suggested for creating compositionally stratified layers. In the interiors of Jupiter and Saturn, these include phase separation of He from metallic hydrogen and dissolution of dense core material into the surrounding metallic-H envelope. Condensation of methane and water has been proposed as a mechanism for producing stable zones in the atmospheres of Saturn and the ice giants. However, if a stably stratified layer is formed adjacent to an active region of convection, it may be susceptible to progressive erosion as the convection intrudes and entrains fluid into the unstable envelope. We discuss the principal factors that control the rate of entrainment and associated erosion and present a specific example concerning the longevity of stable layers formed by condensation of methane and water in Uranus and Neptune. We also consider whether the temporal variability of such layers may engender episodic behavior in the release of the internal heat of these planets. This research is supported by a grant from the NASA Solar System Workings Program.

Effect of stratified inequality of blood flow on gas exchange in liquid-filled lungs.

Science.gov (United States)

West, J. B.; Maloney, J. E.; Castle, B. L.

1972-01-01

This investigation set out to answer two questions: (1) are the distal alveoli in the terminal lung units less well perfused than the proximal alveoli, i.e., is there stratification of blood flow; and (2) if so, does this enhance gas exchange in the presence of stratified inequality of ventilation. Excised dog lungs were ventilated with saline and perfused with blood. Following single inspirations of xenon 133 in saline and various periods of breath holding, the expired xenon concentration against volume was measured and it confirmed marked stratified inequality of ventilation under these conditions. By measuring the rate of depletion of xenon from alveoli during a period of blood flow, we showed that the alveoli which emptied at the end of expiration had 16% less blood flow than those exhaling earlier. However, by measuring the xenon concentration in pulmonary venous blood, we found that about 10% less tracer was transferred from the alveoli into the blood when the inspired xenon was stratified within the respiratory zone. Thus while stratification of blood flow was confirmed, it was shown to impair rather than enhance the efficiency of gas transfer.

STRESS DISTRIBUTION IN THE STRATIFIED MASS CONTAINING VERTICAL ALVEOLE

Directory of Open Access Journals (Sweden)

Bobileva Tatiana Nikolaevna

2017-08-01

Full Text Available Almost all subsurface rocks used as foundations for various types of structures are stratified. Such heterogeneity may cause specific behaviour of the materials under strain. Differential equations describing the behaviour of such materials contain rapidly fluctuating coefficients, in view of this, solution of such equations is more time-consuming when using today’s computers. The method of asymptotic averaging leads to getting homogeneous medium under study to averaged equations with fixed factors. The present article is concerned with stratified soil mass consisting of pair-wise alternative isotropic elastic layers. In the results of elastic modules averaging, the present soil mass with horizontal rock stratification is simulated by homogeneous transversal-isotropic half-space with isotropy plane perpendicular to the standing axis. Half-space is loosened by a vertical alveole of circular cross-section, and virgin ground is under its own weight. For horizontal parting planes of layers, the following two types of surface conditions are set: ideal contact and backlash without cleavage. For homogeneous transversal-isotropic half-space received with a vertical alveole, the analytical solution of S.G. Lekhnitsky, well known in scientific papers, is used. The author gives expressions for stress components and displacements in soil mass for different marginal conditions on the alveole surface. Such research problems arise when constructing and maintaining buildings and when composite materials are used.

E25 stratified torch ignition engine emissions and combustion analysis

International Nuclear Information System (INIS)

Rodrigues Filho, Fernando Antonio; Baêta, José Guilherme Coelho; Teixeira, Alysson Fernandes; Valle, Ramón Molina; Fonseca de Souza, José Leôncio

2016-01-01

Highlights: • A stratified torch ignition (STI) engine was built and tested. • The STI engines was tested in a wide range of load and speed. • Significant reduction on emissions was achieved by means of the STI system. • Low cyclic variability characterized the lean combustion process of the torch ignition engine. • HC emission is the main drawback of the stratified torch ignition engine. - Abstract: Vehicular emissions significantly increase atmospheric air pollution and greenhouse gases (GHG). This fact associated with fast global vehicle fleet growth calls for prompt scientific community technological solutions in order to promote a significant reduction in vehicle fuel consumption and emissions, especially of fossil fuels to comply with future legislation. To meet this goal, a prototype stratified torch ignition (STI) engine was built from a commercial existing baseline engine. In this system, combustion starts in a pre-combustion chamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main chamber. These combustion jet flames are endowed with high thermal and kinetic energy, being able to generate a stable lean combustion process. The high kinetic and thermal energy of the combustion jet flame results from the load stratification. This is carried out through direct fuel injection in the pre-combustion chamber by means of a prototype gasoline direct injector (GDI) developed for a very low fuel flow rate. In this work the engine out-emissions of CO, NOx, HC and CO_2 of the STI engine are presented and a detailed analysis supported by the combustion parameters is conducted. The results obtained in this work show a significant decrease in the specific emissions of CO, NOx and CO_2 of the STI engine in comparison with the baseline engine. On the other hand, HC specific emission increased due to wall wetting from the fuel hitting in the pre-combustion chamber wall.

Doubly stratified mixed convection flow of Maxwell nanofluid with heat generation/absorption

Energy Technology Data Exchange (ETDEWEB)

Abbasi, F.M., E-mail: abbasisarkar@gmail.com [Department of Mathematics, Comsats Institute of Information Technology, Islamabad 44000 (Pakistan); Shehzad, S.A. [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Hayat, T. [Department of Mathematics, Quaid-i-Azam University, 45320, Islamabad 44000 (Pakistan); NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Ahmad, B. [NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2016-04-15

Magnetohydrodynamic (MHD) doubly stratified flow of Maxwell nanofluid in presence of mixed convection is analyzed in this article. Effects of thermophoresis, Brownian motion and heat generation/absorption are present. The flow is induced due to linear stretching of sheet. Mathematical formulation is made under boundary layer approach. Expressions of velocity, temperature and nanoparticles concentration are developed. The obtained results are plotted and discussed to examine the variations in temperature and nanoparticles concentration due to different physical parameters. Numerical computations are made to obtain the values of local Nusselt and Sherwood numbers. Impact of sundry parameters on the flow quantities is analyzed graphically. - Highlights: • Double stratified flow of Maxwell nanofluid with mixed convection is modeled. • Thermophoresis and Brownian motion effects are encountered. • Computations are made to obtain the solution expressions. • Numerical values of local Nusselt and Sherwood numbers are computed and examined.

PENGARUH MEDIA PEMBELAJARAN DAN STRATEGI BELAJAR TERHADAP HASIL BELAJAR SISWA KELAS X PADA MATA PELAJARAN EKONOMI SMA SEDES SAPIENTIAE SEMARANG (studi pada tahun ajaran 2015/2016.

Directory of Open Access Journals (Sweden)

Desi Marintan

2017-02-01

Full Text Available According to early observation in Sedes Sapientaie Semarang Senior High School the learning’s result of economic subject is still in low category.The purpose of this research to know the influence of study media and learning study towards learning’s result of the students who are in X grade at economic subject in Sedes Sapientiae Semarang Senior High School. The population of this research is all the X student’s class in Sedes Sapientiae Semarang Senior High School by using Proportionate Stratified Random Sampling technique. Result of this research indicates that silmutantly media of study and learning strategy towards learning’s result at economic subject has effect 58,4%. And partially, media of study has effect toward’s learning’s result of economic subjects amount 25,00% and learning strategy towards students learning’s result at economic subject as amount 20,25%. Based to the research, can be conduded that media of study and learning strategy have positive effects towards the learning result of X class students at economic subject simultantly or partially.

Media identities and media-influenced indentifications Visibility and identity recognition in the media

Directory of Open Access Journals (Sweden)

Víctor Fco. Sampedro Blanco

2004-10-01

Full Text Available The media establish, in large part, the patterns of visibility and public recognition of collective identities. We define media identities as those that are the object of production and diffusion by the media. From this discourse, the communities and individuals elaborate media-influenced identifications; that is, processes of recognition or banishment; (rearticulating the identity markers that the media offer with other cognitive and emotional sources. The generation and appropriation of the identities are subjected to a media hierarchisation that influences their normalisation or marginalisation. The identities presented by the media and assumed by the audience as part of the official, hegemonic discourse are normalised, whereas the identities and identifications formulated in popular and minority terms are marginalised. After presenting this conceptual and analytical framework, this study attempts to outline the logics that condition the presentation, on the one hand, andthe public recognition, on the other hand, of contemporary identities.

Magnetic coordinates for equilibria with a continuous symmetry

International Nuclear Information System (INIS)

Dewar, R.L.; Monticello, D.A.; Sy, W.N.C.

1983-08-01

Magnetic coordinates for hydromagnetic equilibria are defined which treat toroidal and straight helical plasmas equivalently yet exploit the existence of a continuous symmetry to derive relations between various geometrical and physical quantities. This allows the number of equilibrium quantities which must be known to be reduced to a minimal, or primitive set. Practical formulae for various quantities required in hydromagnetic stability calculations (interchange, ballooning, and global) are given in terms of this primitive set

Community genomics among stratified microbial assemblages in the ocean's interior

DEFF Research Database (Denmark)

DeLong, Edward F; Preston, Christina M; Mincer, Tracy

2006-01-01

Microbial life predominates in the ocean, yet little is known about its genomic variability, especially along the depth continuum. We report here genomic analyses of planktonic microbial communities in the North Pacific Subtropical Gyre, from the ocean's surface to near-sea floor depths. Sequence......, and host-viral interactions. Comparative genomic analyses of stratified microbial communities have the potential to provide significant insight into higher-order community organization and dynamics....

Mathematical modeling of turbulent stratified flows. Application of liquid metal fast breeders

Energy Technology Data Exchange (ETDEWEB)

Villand, M; Grand, D [CEA-Service des Transferts Thermiques, Grenoble (France)

1983-07-01

Mathematical model of turbulent stratified flow was proposed under the following assumptions: Newtonian fluid; incompressible fluid; coupling between temperature and momentum fields according to Boussinesq approximation; two-dimensional invariance for translation or rotation; coordinates cartesian or curvilinear. Solutions obtained by the proposed method are presented.

The effects of ventilation tubes versus no ventilation tubes for recurrent acute otitis media or chronic otitis media with effusion in 9 to 36 month old Greenlandic children, the SIUTIT trial: study protocol for a randomized controlled trial.

Science.gov (United States)

Demant, Malene Nøhr; Jensen, Ramon Gordon; Jakobsen, Janus Christian; Gluud, Christian; Homøe, Preben

2017-01-19

The prevalence of otitis media in Greenlandic children is one of the highest in the world. International studies have shown that otitis-prone children may benefit from tubulation of the tympanic membrane. However, it is unknown whether these results can be applied to Greenlandic children and trials on the effects of ventilation tubes in high-risk populations have, to our knowledge, never been conducted. The trial is an investigator-initiated, multicentre, randomized, blinded superiority trial of bilateral ventilation tube insertion versus treatment as usual (no tube) in Greenlandic children aged 9-36 months with chronic otitis media with effusion or recurrent acute otitis media. With randomization stratified by otitis media subtype and trial site, a type 1 error of 5% and a power of 80%, a total of 230 participants are needed to detect a decrease of two visits to a health clinic during 2 years, which is considered the minimal clinical relevant difference. The primary outcome measure will be assessed blindly by investigating medical records. Secondary outcome measures are number of episodes of acute otitis media, quality of life, number of episodes of antibiotics administration and proportion of children with tympanic membrane perforations. This trial will provide evidence-based knowledge of the effects of ventilation tubes in children with middle ear infections from the high-risk Greenlandic population. Furthermore, this trial will improve the understanding of conducting randomized clinical trials in remote areas, where management of logistical aspects is particularly challenging. ClinicalTrials.gov, NCT02490332 . Registered on 14 February 2016.

Experimental and numerical investigation of stratified gas-liquid flow in inclined circular pipes

International Nuclear Information System (INIS)

Faccini, J.L.H.; Sampaio, P.A.B. de; Botelho, M.H.D.S.; Cunha, M.V.; Cunha Filho, J.S.; Su, J.

2012-01-01

In this paper, a stratified gas-liquid flow is experimentally and numerically investigated. Two measurement techniques, namely an ultrasonic technique and a visualization technique, are applied on an inclined circular test section using a fast single transducer pulse-echo technique and a high-speed camera. A numerical model is employed to simulate the stratified gas-liquid flow, formed by a system of non-linear differential equations consisting of the Reynolds averaged Navier-Stokes equations with the κ-ω turbulence model. The test section used in this work is comprised mainly of a transparent circular pipe with inner diameter 1 inch, and inclination angles varying from -2.5 to -10.0 degrees. Numerical solutions are obtained for the liquid height as a function of inclination angles, and compared with our own experimental data. (author)

Analysis of flame propagation phenomenon in simplified stratified charge conditions; Tanjunkasareta sojo kyukiba ni okeru kaen denpa gensho no kansatsu

Energy Technology Data Exchange (ETDEWEB)

Moriyoshi, Y; Morikawa, H [Chiba University, Chiba (Japan); Kamimoto, T [Tokyo Institute of Technology, Tokyo (Japan)

1997-10-01

Since the local inhomogeneity of mixture concentration inside the cylinder affects the combustion characteristics, a basic research on combustion phenomenon in stratified charge conditions is required. The authors have made experiments with a constant-volume chamber, which can simulate an idealized stratified charge field by using a removable partition, to obtain the combustion characteristics. Also, numerical calculations are made using some combustion models. As a result, the important feature that the combustion speed is faster in stratified condition than in homogeneous condition can be predicted by the two-step reaction model. 4 refs., 8 figs.

Komunikasi Krisis di Era New Media dan Social Media

OpenAIRE

Prastya, Narayana Mahendra

2016-01-01

New media and social media have changed the practice of public relations. One area that changed is crisis communication. Because of these new technologies, crisis can be more complex. The pace of information, the uncertainty, and the rumors, are increasing. Public relations practitioners should include the new media and social media use in their crisis communication plan. Before doing that, public relations practitioners should change their mindset about social media and new media. The first ...

Dominance of a clonal green sulfur bacterial population in a stratified lake

DEFF Research Database (Denmark)

Gregersen, Lea H; Habicht, Kirsten S; Peduzzi, Sandro

2009-01-01

surveys using FISH cell counting and population multilocus sequence typing [clone library sequence analysis of the small subunit (SSU) rRNA locus and two loci involved in photosynthesis in GSB: fmoA and csmCA]. All bacterial populations clearly stratified according to water column chemistry. The GSB...

LES of stratified-wavy flows using novel near-interface treatment

Science.gov (United States)

Karnik, Aditya; Kahouadji, Lyes; Chergui, Jalel; Juric, Damir; Shin, Seungwon; Matar, Omar K.

2017-11-01

The pressure drop in horizontal stratified wavy flows is influenced by interfacial shear stress. The near-interface behavior of the lighter phase is akin to that near a moving wall. We employ a front-tracking code, Blue, to simulate and capture the near-interface behaviour of both phases. Blue uses a modified Smagorinsky LES model incorporating a novel near-interface treatment for the sub-grid viscosity, which is influenced by damping due to the wall-like interface, and enhancement of the turbulent kinetic energy (TKE) due to the interfacial waves. Simulations are carried out for both air-water and oil-water stratified configurations to demonstrate the applicability of the present method. The mean velocities and tangential Reynolds stresses are compared with experiments for both configurations. At the higher Re, the waves penetrate well into the buffer region of the boundary layer above the interface thus altering its dynamics. Previous attempts to capture the secondary structures associated with such flows using RANS or standard LES methodologies have been unsuccessful. The ability of the present method to reproduce these structures is due to the correct estimation of the near-interface TKE governing energy transfer from the normal to tangential directions. EPSRC, UK, MEMPHIS program Grant (EP/K003976/1), RAEng Research Chair (OKM).

Media education and media enlightenment as attributes of information society

Directory of Open Access Journals (Sweden)

Лилия Борисовна Белоглазова

2014-12-01

Full Text Available The article deals with the problem of the functioning of media-education and media-enlightenment in modern society. Focuses on the impact of this socio-cultural phenomenon on consciousness of members of the Information Society. Are the main characteristics of media-education and media-education and media-enlightenment. Concludes that media-education and media-enlightenment forms unscientific and anti-scientific thinking and style speech.

Sensitive Media

Directory of Open Access Journals (Sweden)

Malinowska Anna

2017-12-01

Full Text Available The paper engages with what we refer to as “sensitive media,” a concept associated with developments in the overall media environment, our relationships with media devices, and the quality of the media themselves. Those developments point to the increasing emotionality of the media world and its infrastructures. Mapping the trajectories of technological development and impact that the newer media exert on human condition, our analysis touches upon various forms of emergent affect, emotion, and feeling in order to trace the histories and motivations of the sensitization of “the media things” as well as the redefinition of our affective and emotional experiences through technologies that themselves “feel.”

Modification of Measures of Acute Kidney Injury to Risk Stratify Combat Casualties

Science.gov (United States)

2017-08-26

REPORT TYPE 08/26/2017 Poster 4. TJTLE AND SUBTITLE t\\.1odification of l’vfeasures,of Acute Kidney Injury to Risk Stratify Cotnbat Casualties 6...profiles and potential future conflicts , identifying acute kidney injury (AKI) early can help us determine the need for rapidity of evacuation

Social Media Sites

Science.gov (United States)

Media Sites Site Registration Contact Us Search AF.mil: Home > AF Sites > Social Media Sites Social Media Welcome to the Air Force social media directory! The directory is a one-stop shop of official Air Force social media pages across various social media sites. Social media is all about

Stereotypes in media and media literacy among young people

Directory of Open Access Journals (Sweden)

Đerić Ivana

2006-01-01

Full Text Available Young people, the most common consumers of media content, bear out the view that media shapes people’s lives. Therefore we must not underestimate the effect media exerts on young people’s values and behavioral patterns. Television is the medium which draws children and young people for the greatest part of their free time. Regardless whether television programs are described as positive or negative, whether they abound with stereotypes or not, it is important that young people develop a critical attitude towards them so that they may resist different forms of media manipulation. The paper discusses how stereotypes are generated and used by media and the manners in which stereotypical concepts affect young people’s attitudes. It highlights the importance of the development of media literacy which implies a critical attitude towards media images and discourses, the development of criteria for the selection and evaluation of information broadcast by media, the development of skills in interpreting and understanding stereotypical concepts and familiarity with alternative forms of media culture. The paper draws special attention to the issue of media education. The conclusion is that schools should offer media literacy as part of their curriculum and in it possible solutions to the problems discussed. .

Rapid shelf-wide cooling response of a stratified coastal ocean to hurricanes.

Science.gov (United States)

Seroka, Greg; Miles, Travis; Xu, Yi; Kohut, Josh; Schofield, Oscar; Glenn, Scott

2017-06-01

Large uncertainty in the predicted intensity of tropical cyclones (TCs) persists compared to the steadily improving skill in the predicted TC tracks. This intensity uncertainty has its most significant implications in the coastal zone, where TC impacts to populated shorelines are greatest. Recent studies have demonstrated that rapid ahead-of-eye-center cooling of a stratified coastal ocean can have a significant impact on hurricane intensity forecasts. Using observation-validated, high-resolution ocean modeling, the stratified coastal ocean cooling processes observed in two U.S. Mid-Atlantic hurricanes were investigated: Hurricane Irene (2011)-with an inshore Mid-Atlantic Bight (MAB) track during the late summer stratified coastal ocean season-and Tropical Storm Barry (2007)-with an offshore track during early summer. For both storms, the critical ahead-of-eye-center depth-averaged force balance across the entire MAB shelf included an onshore wind stress balanced by an offshore pressure gradient. This resulted in onshore surface currents opposing offshore bottom currents that enhanced surface to bottom current shear and turbulent mixing across the thermocline, resulting in the rapid cooling of the surface layer ahead-of-eye-center. Because the same baroclinic and mixing processes occurred for two storms on opposite ends of the track and seasonal stratification envelope, the response appears robust. It will be critical to forecast these processes and their implications for a wide range of future storms using realistic 3-D coupled atmosphere-ocean models to lower the uncertainty in predictions of TC intensities and impacts and enable coastal populations to better respond to increasing rapid intensification threats in an era of rising sea levels.

Rapid shelf‐wide cooling response of a stratified coastal ocean to hurricanes

Science.gov (United States)

Miles, Travis; Xu, Yi; Kohut, Josh; Schofield, Oscar; Glenn, Scott

2017-01-01

Abstract Large uncertainty in the predicted intensity of tropical cyclones (TCs) persists compared to the steadily improving skill in the predicted TC tracks. This intensity uncertainty has its most significant implications in the coastal zone, where TC impacts to populated shorelines are greatest. Recent studies have demonstrated that rapid ahead‐of‐eye‐center cooling of a stratified coastal ocean can have a significant impact on hurricane intensity forecasts. Using observation‐validated, high‐resolution ocean modeling, the stratified coastal ocean cooling processes observed in two U.S. Mid‐Atlantic hurricanes were investigated: Hurricane Irene (2011)—with an inshore Mid‐Atlantic Bight (MAB) track during the late summer stratified coastal ocean season—and Tropical Storm Barry (2007)—with an offshore track during early summer. For both storms, the critical ahead‐of‐eye‐center depth‐averaged force balance across the entire MAB shelf included an onshore wind stress balanced by an offshore pressure gradient. This resulted in onshore surface currents opposing offshore bottom currents that enhanced surface to bottom current shear and turbulent mixing across the thermocline, resulting in the rapid cooling of the surface layer ahead‐of‐eye‐center. Because the same baroclinic and mixing processes occurred for two storms on opposite ends of the track and seasonal stratification envelope, the response appears robust. It will be critical to forecast these processes and their implications for a wide range of future storms using realistic 3‐D coupled atmosphere‐ocean models to lower the uncertainty in predictions of TC intensities and impacts and enable coastal populations to better respond to increasing rapid intensification threats in an era of rising sea levels. PMID:28944132

Stratified prevention: opportunities and limitations. Report on the 1st interdisciplinary cardiovascular workshop in Augsburg.

Science.gov (United States)

Kirchhof, Gregor; Lindner, Josef Franz; Achenbach, Stephan; Berger, Klaus; Blankenberg, Stefan; Fangerau, Heiner; Gimpel, Henner; Gassner, Ulrich M; Kersten, Jens; Magnus, Dorothea; Rebscher, Herbert; Schunkert, Heribert; Rixen, Stephan; Kirchhof, Paulus

2018-03-01

Sufficient exercise and sleep, a balanced diet, moderate alcohol consumption and a good approach to handle stress have been known as lifestyles that protect health and longevity since the Middle Age. This traditional prevention quintet, turned into a sextet by smoking cessation, has been the basis of the "preventive personality" that formed in the twentieth century. Recent analyses of big data sets including genomic and physiological measurements have unleashed novel opportunities to estimate individual health risks with unprecedented accuracy, allowing to target preventive interventions to persons at high risk and at the same time to spare those in whom preventive measures may not be needed or even be harmful. To fully grasp these opportunities for modern preventive medicine, the established healthy life styles require supplementation by stratified prevention. The opportunities of these developments for life and health contrast with justified concerns: A "surveillance society", able to predict individual behaviour based on big data, threatens individual freedom and jeopardises equality. Social insurance law and the new German Disease Prevention Act (Präventionsgesetz) rightly stress the need for research to underpin stratified prevention which is accessible to all, ethical, effective, and evidence based. An ethical and acceptable development of stratified prevention needs to start with autonomous individuals who control and understand all information pertaining to their health. This creates a mandate for lifelong health education, enabled in an individualised form by digital technology. Stratified prevention furthermore requires the evidence-based development of a new taxonomy of cardiovascular diseases that reflects disease mechanisms. Such interdisciplinary research needs broad support from society and a better use of biosamples and data sets within an updated research governance framework.

Some recent developments in the theoretical dynamics of magnetic fields

International Nuclear Information System (INIS)

Low, B.C.

1986-01-01

This article describes recent developments in the theoretical investigation of magnetostatic equilibrium in the presence of gravity, nonequilibrium in hydromagnetics, and classical problems in hydromagnetic stability. The construction of magnetostatic dequilibria has progressed beyond geometrically idealized systems, such as the axisymmetric system, to fully three-dimensional systems capable of modelling realistic solar structures. Nonequilibrium in a magnetic field with an arbitrary interweaving of lines of force due to random footpoint motion is a novel and subtle property with important implications for the solar atmosphere. To the extent quasi-static solar structures are approximated by stable equilibrium, ideal hydromagnetic stability theory provides a first insight into how stability is achieved in the solar environment. A qualitative physical picture based on recent stability analyses is given. The article places emphasis on understanding basic principles and issues rather than detailed results which can be found in the published literature

An analysis direct-contact condensation in horizontal cocurrent stratified flow of steam and cold water

International Nuclear Information System (INIS)

Lee, Suk Ho; Kim, Hho Jung

1992-01-01

The physical benchmark problem on the direct-contact condensation under the horizontal cocurrent stratified flow was analyzed using the RELAP5/MOD2 and /MOD3 one-dimensional model. Analysis was performed for the Northwestern experiments, which involved condensing steam/water flow in a rectangular channel. The study showed that the RELAP5 interfacial heat transfer model, under the horizontal stratified flow regime, predicted the condensation rate well though the interfacial heat transfer area was underpredicted. However, some discrepancies in water layer thickness and local heat transfer coefficient with experimental results were found especially when there is a wavy interface, and those were satisfied only within the range. (Author)

Media evolution and ‘epi-technic’ digital media: Media as cultural selection mechanisms

DEFF Research Database (Denmark)

Olesen, Mogens

2016-01-01

The explosive development of new digital media technologies is often described as a media evolution but hardly ever is the concept of ‘media evolution’ taken at face value. This article takes up that challenge by combining cultural evolution theories with medium theory. The article argues that bi...

Risk Factors for Emergency Department Short Time Readmission in Stratified Population

Directory of Open Access Journals (Sweden)

Ariadna Besga

2015-01-01

Full Text Available Background. Emergency department (ED readmissions are considered an indicator of healthcare quality that is particularly relevant in older adults. The primary objective of this study was to identify key factors for predicting patients returning to the ED within 30 days of being discharged. Methods. We analysed patients who attended our ED in June 2014, stratified into four groups based on the Kaiser pyramid. We collected data on more than 100 variables per case including demographic and clinical characteristics and drug treatments. We identified the variables with the highest discriminating power to predict ED readmission and constructed classifiers using machine learning methods to provide predictions. Results. Classifier performance distinguishing between patients who were and were not readmitted (within 30 days, in terms of average accuracy (AC. The variables with the greatest discriminating power were age, comorbidity, reasons for consultation, social factors, and drug treatments. Conclusions. It is possible to predict readmissions in stratified groups with high accuracy and to identify the most important factors influencing the event. Therefore, it will be possible to develop interventions to improve the quality of care provided to ED patients.

Decision tree analysis to stratify risk of de novo non-melanoma skin cancer following liver transplantation.

Science.gov (United States)

Tanaka, Tomohiro; Voigt, Michael D

2018-03-01

Non-melanoma skin cancer (NMSC) is the most common de novo malignancy in liver transplant (LT) recipients; it behaves more aggressively and it increases mortality. We used decision tree analysis to develop a tool to stratify and quantify risk of NMSC in LT recipients. We performed Cox regression analysis to identify which predictive variables to enter into the decision tree analysis. Data were from the Organ Procurement Transplant Network (OPTN) STAR files of September 2016 (n = 102984). NMSC developed in 4556 of the 105984 recipients, a mean of 5.6 years after transplant. The 5/10/20-year rates of NMSC were 2.9/6.3/13.5%, respectively. Cox regression identified male gender, Caucasian race, age, body mass index (BMI) at LT, and sirolimus use as key predictive or protective factors for NMSC. These factors were entered into a decision tree analysis. The final tree stratified non-Caucasians as low risk (0.8%), and Caucasian males > 47 years, BMI decision tree model accurately stratifies the risk of developing NMSC in the long-term after LT.

Direct numerical simulation of homogeneous stratified rotating turbulence

Energy Technology Data Exchange (ETDEWEB)

Iida, O.; Tsujimura, S.; Nagano, Y. [Nagoya Institute of Technology, Department of Mech. Eng., Nagoya (Japan)

2005-12-01

The effects of the Prandtl number on stratified rotating turbulence have been studied in homogeneous turbulence by using direct numerical simulations and a rapid distortion theory. Fluctuations under strong stable-density stratification can be theoretically divided into the WAVE and the potential vorticity (PV) modes. In low-Prandtl-number fluids, the WAVE mode deteriorates, while the PV mode remains. Imposing rotation on a low-Prandtl-number fluid makes turbulence two-dimensional as well as geostrophic; it is found from the instantaneous turbulent structure that the vortices merge to form a few vertically-elongated vortex columns. During the period toward two-dimensionalization, the vertical vortices become asymmetric in the sense of rotation. (orig.)

Trolling new media: violent extremist groups recruiting through social media

OpenAIRE

Chang, Mark D.

2015-01-01

Approved for public release; distribution is unlimited With the advent and subsequent growth of several new media technologies, violent extremist groups have incorporated social media into recruiting strategies. How are violent extremist groups using social media for recruiting? This thesis explores several new media technologies—websites, blogs, social media, mobile phones, and online gaming—to determine if violent extremist groups rely on social media for recruiting. By comparing the com...

Media education.

Science.gov (United States)

Strasburger, Victor C

2010-11-01

The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents.

Designing Wood Supply Scenarios from Forest Inventories with Stratified Predictions

Directory of Open Access Journals (Sweden)

Philipp Kilham

2018-02-01

Full Text Available Forest growth and wood supply projections are increasingly used to estimate the future availability of woody biomass and the correlated effects on forests and climate. This research parameterizes an inventory-based business-as-usual wood supply scenario, with a focus on southwest Germany and the period 2002–2012 with a stratified prediction. First, the Classification and Regression Trees algorithm groups the inventory plots into strata with corresponding harvest probabilities. Second, Random Forest algorithms generate individual harvest probabilities for the plots of each stratum. Third, the plots with the highest individual probabilities are selected as harvested until the harvest probability of the stratum is fulfilled. Fourth, the harvested volume of these plots is predicted with a linear regression model trained on harvested plots only. To illustrate the pros and cons of this method, it is compared to a direct harvested volume prediction with linear regression, and a combination of logistic regression and linear regression. Direct harvested volume regression predicts comparable volume figures, but generates these volumes in a way that differs from business-as-usual. The logistic model achieves higher overall classification accuracies, but results in underestimations or overestimations of harvest shares for several subsets of the data. The stratified prediction method balances this shortcoming, and can be of general use for forest growth and timber supply projections from large-scale forest inventories.

Transition of Gas-Liquid Stratified Flow in Oil Transport Pipes

Directory of Open Access Journals (Sweden)

D. Lakehal

2011-12-01

Full Text Available Large-Scale Simulation results of the transition of a gas-liquid stratified flow to slug flow regime in circular 3D oil transport pipes under turbulent flow conditions expressed. Free surface flow in the pipe is treated using the Level Set method. Turbulence is approached via the LES and VLES methodologies extended to interfacial two-phase flows. It is shown that only with the Level Set method the flow transition can be accurately predicted, better than with the two-fluid phase-average model. The transition from stratified to slug flow is found to be subsequent to the merging of the secondary wave modes created by the action of gas shear (short waves with the first wave mode (high amplitude long wave. The model is capable of predicting global flow features like the onset of slugging and slug speed. In the second test case, the model predicts different kinds of slugs, the so-called operating slugs formed upstream that fill entirely the pipe with water slugs of length scales of the order of 2-4 D, and lower size (1-1.5 D disturbance slugs, featuring lower hold-up (0.8-0.9. The model predicts well the frequency of slugs. The simulations revealed important parameter effects on the results, such as two-dimensionality, pipe length, and water holdup.

Experimental observation of the stratified electrothermal instability on aluminum with thickness greater than a skin depth

Science.gov (United States)

Hutchinson, T. M.; Awe, T. J.; Bauer, B. S.; Yates, K. C.; Yu, E. P.; Yelton, W. G.; Fuelling, S.

2018-05-01

A direct observation of the stratified electrothermal instability on the surface of thick metal is reported. Aluminum rods coated with 70 μ m Parylene-N were driven to 1 MA in 100 ns , with the metal thicker than the skin depth. The dielectric coating suppressed plasma formation, enabling persistent observation of discrete azimuthally correlated stratified thermal perturbations perpendicular to the current whose wave numbers, k , grew exponentially with rate γ (k ) =0.06 n s-1-(0.4 n s-1μ m2ra d-2 ) k2 in ˜1 g /c m3 , ˜7000 K aluminum.

Experimental Observation of the Stratified Electrothermal Instability on Aluminum with Thickness Greater than a Skin Depth

Energy Technology Data Exchange (ETDEWEB)

Hutchinson, Trevor M. [Univ. of Nevada, Reno, NV (United States); Hutchinson, Trevor M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Awe, Thomas James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Bruno S. [Univ. of Nevada, Reno, NV (United States); Yates, Kevin [Univ. of New Mexico, Albuquerque, NM (United States); Yu, Edmund p. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yelton, William G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fuelling, Stephan [Univ. of Nevada, Reno, NV (United States)

2017-07-01

The first direct observation of the stratified electrothermal instability on the surface of thick metal is reported. Aluminum rods coated with 70 μm Parylene-N were driven to 1 MA in approximately 100 ns, with the metal thicker than the skin depth. The dielectric coating suppressed plasma formation, enabling persistent observation of discrete azimuthally-correlated stratified structures perpendicular to the current. Strata amplitudes grow rapidly, while their Fourier spectrum shifts toward longer wavelength. Assuming blackbody emission, radiometric calculations indicate strata are temperature perturbations that grow exponentially with rate γ = 0.04 ns -1 in 3000- 10,000 K aluminum.

Media Framing

DEFF Research Database (Denmark)

Pedersen, Rasmus T.

2017-01-01

The concept of media framing refers to the way in which the news media organize and provide meaning to a news story by emphasizing some parts of reality and disregarding other parts. These patterns of emphasis and exclusion in news coverage create frames that can have considerable effects on news...... consumers’ perceptions and attitudes regarding the given issue or event. This entry briefly elaborates on the concept of media framing, presents key types of media frames, and introduces the research on media framing effects....

Direct numerical simulation of thermally-stratified turbulent boundary layer subjected to adverse pressure gradient

International Nuclear Information System (INIS)

Hattori, Hirofumi; Kono, Amane; Houra, Tomoya

2016-01-01

Highlights: • We study various thermally-stratified turbulent boundary layers having adverse pressure gradient (APG) by means of DNS. • The detailed turbulent statistics and structures in various thermally-stratified turbulent boundary layers having APG are discussed. • It is found that the friction coefficient and Stanton number decrease along the streamwise direction due to the effects of stable thermal stratification and APG, but those again increase due to the APG effect in the case of weak stable thermal stratification. • In the case of strong stable stratification with or without APG, the flow separation is observed in the downstream region. - Abstract: The objective of this study is to investigate and observe turbulent heat transfer structures and statistics in thermally-stratified turbulent boundary layers subjected to a non-equilibrium adverse pressure gradient (APG) by means of direct numerical simulation (DNS). DNSs are carried out under conditions of neutral, stable and unstable thermal stratifications with a non-equilibrium APG, in which DNS results reveal heat transfer characteristics of thermally-stratified non-equilibrium APG turbulent boundary layers. In cases of thermally-stratified turbulent boundary layers affected by APG, heat transfer performances increase in comparison with a turbulent boundary layer with neutral thermal stratification and zero pressure gradient (ZPG). Especially, it is found that the friction coefficient and Stanton number decrease along the streamwise direction due to the effects of stable thermal stratification and APG, but those again increase due to the APG effect in the case of weak stable thermal stratification (WSBL). Thus, the analysis for both the friction coefficient and Stanton number in the case of WSBL with/without APG is conducted using the FIK identity in order to investigate contributions from the transport equations, in which it is found that both Reynolds-shear-stress and the mean convection terms

Experimental investigation on isothermal stratified flow mixing in a horizontal T-junction

Energy Technology Data Exchange (ETDEWEB)

Isaev, Alexander; Kulenovic, Rudi; Laurien, Eckart [Stuttgart Univ. (Germany). Inst. fuer Kernenergetik und Energiesysteme (IKE)

2016-10-15

Turbulent and stratified flows can lead to thermal fatigue in piping systems of nuclear power plants (NPP). Such flows can be investigated in the University of Stuttgart Fluid-Structure-Interaction (FSI) facility with a T-Junction at thermal conditions with temperature differences of up to 255 K and at pressures of maximum 75 bars.

Numerical simulation of stratified shear flow using a higher order Taylor series expansion method

Energy Technology Data Exchange (ETDEWEB)

Iwashige, Kengo; Ikeda, Takashi [Hitachi, Ltd. (Japan)

1995-09-01

A higher order Taylor series expansion method is applied to two-dimensional numerical simulation of stratified shear flow. In the present study, central difference scheme-like method is adopted for an even expansion order, and upwind difference scheme-like method is adopted for an odd order, and the expansion order is variable. To evaluate the effects of expansion order upon the numerical results, a stratified shear flow test in a rectangular channel (Reynolds number = 1.7x10{sup 4}) is carried out, and the numerical velocity and temperature fields are compared with experimental results measured by laser Doppler velocimetry thermocouples. The results confirm that the higher and odd order methods can simulate mean velocity distributions, root-mean-square velocity fluctuations, Reynolds stress, temperature distributions, and root-mean-square temperature fluctuations.

Scattering by multiple parallel radially stratified infinite cylinders buried in a lossy half space.

Science.gov (United States)

Lee, Siu-Chun

2013-07-01

The theoretical solution for scattering by an arbitrary configuration of closely spaced parallel infinite cylinders buried in a lossy half space is presented in this paper. The refractive index and permeability of the half space and cylinders are complex in general. Each cylinder is radially stratified with a distinct complex refractive index and permeability. The incident radiation is an arbitrarily polarized plane wave propagating in the plane normal to the axes of the cylinders. Analytic solutions are derived for the electric and magnetic fields and the Poynting vector of backscattered radiation emerging from the half space. Numerical examples are presented to illustrate the application of the scattering solution to calculate backscattering from a lossy half space containing multiple homogeneous and radially stratified cylinders at various depths and different angles of incidence.

Stability of unstably stratified shear flow between parallel plates

Energy Technology Data Exchange (ETDEWEB)

Fujimura, Kaoru; Kelly, R E

1987-09-01

The linear stability of unstably stratified shear flows between two horizontal parallel plates was investigated. Eigenvalue problems were solved numerically by making use of the expansion method in Chebyshev polynomials, and the critical Rayleigh numbers were obtained accurately in the Reynolds number range of (0.01, 100). It was found that the critical Rayleigh number increases with an increase of the Reynolds number. The result strongly supports previous stability analyses except for the analysis by Makino and Ishikawa (J. Jpn. Soc. Fluid Mech. 4 (1985) 148 - 158) in which a decrease of the critical Rayleigh number was obtained.

Stability of unstably stratified shear flow between parallel plates

International Nuclear Information System (INIS)

Fujimura, Kaoru; Kelly, R.E.

1987-01-01

The linear stability of unstably stratified shear flows between two horizontal parallel plates was investigated. Eigenvalue problems were solved numerically by making use of the expansion method in Chebyshev polynomials, and the critical Rayleigh numbers were obtained accurately in the Reynolds number range of [0.01, 100]. It was found that the critical Rayleigh number increases with an increase of the Reynolds number. The result strongly supports previous stability analyses except for the analysis by Makino and Ishikawa [J. Jpn. Soc. Fluid Mech. 4 (1985) 148 - 158] in which a decrease of the critical Rayleigh number was obtained. (author)

Measures to assess the prognostic ability of the stratified Cox proportional hazards model

DEFF Research Database (Denmark)

(Tybjaerg-Hansen, A.) The Fibrinogen Studies Collaboration.The Copenhagen City Heart Study; Tybjærg-Hansen, Anne

2009-01-01

Many measures have been proposed to summarize the prognostic ability of the Cox proportional hazards (CPH) survival model, although none is universally accepted for general use. By contrast, little work has been done to summarize the prognostic ability of the stratified CPH model; such measures...

The Inverse Relationship between Digital Media Exposure and Childhood Flourishing.

Science.gov (United States)

Ruest, Stephanie; Gjelsvik, Annie; Rubinstein, Max; Amanullah, Siraj

2018-06-01

To describe the relationship between digital media exposure (DME) and parental perception of childhood flourishing, or overall positive well-being. It is hypothesized that there is an inverse association between parent-reported measures of childhood flourishing and increasing daily DME. Parental responses for children ages 6-17 years (N = 64 464) from the 2011-2012 National Survey of Children's Health were analyzed. Average weekday DME that was not school work related was categorized in 2-hour intervals: 0 to education level, there was a dose-dependent decrease in the odds of demonstrating all 5 markers of flourishing as weekday DME increased (test for trend for each outcome P < .001). In stratified analyses, this relationship held true regardless of the child's age group, sex, or poverty level. This study provides evidence that, among school-aged children, increasing weekday DME has an inverse dose-dependent relationship with multiple childhood flourishing markers. Copyright © 2017 Elsevier Inc. All rights reserved.

Media Entrepreneurship

DEFF Research Database (Denmark)

Khajeheian, Datis

2017-01-01

Media Entrepreneurship has been an ambiguous, unclear and controversial concept and despite of growing academic efforts in the last decade, it is still a poorly defined subject. This paper is an effort to fill this gap by providing a comprehensive definition of media entrepreneurship. Firstly......, a literature review conducted and entrepreneurship, media, opportunity and innovation as building blocks of media entrepreneurship explained. Then by using of a mixed of bibliographic method and a Delphi method with multi-stage analysis process, a consensual definition of media entrepreneurship proposed...... entrepreneurship....

Stratified flows and internal waves in the Vema Fracture Zone of the Mid Atlantic Ridge

Science.gov (United States)

Makarenko, Nikolay; Morozov, Eugene; Tarakanov, Roman; Demidova, Tatiana; Frey, Dmitri; Grigorenko, Klim

2017-04-01

In this paper, we study stratified flows and internal waves in the Vema fracture zone of the Mid Atlantic Ridge. This fracture provides intense transportation of cold abyssal waters from the West Atlantic to the equatorial region of the East Atlantic [1]. The results of measurements [2,3] carried out in the cruises of RV Akademik Sergey Vavilov in 2014-2016 are presented. The structure of the near-bottom flow is studied experimentally on the basis of CTD- and LADCP profiling. Theoretical analysis involves mathematical formulation of stratified fluid flow which uses CTD-data obtained from field observation. Spectral properties and kinematic characteristics of internal waves are calculated and discussed. This work was supported by RFBR (grants No 15-01-03942, 16-35-50158). References [1] Morozov E., Demidov A., Tarakanov R. and Zenk W. Abyssal Channels in the Atlantic Ocean: Water Structure and Flows, Springer, Dordrecht, 2010. [2] Morozov E.G., Tarakanov R.Yu., and Makarenko N.I. Flows of Antarctic Bottom Water through fractures in the southern part of the North Mid Atlantic Ridge, Oceanology, 2015, 55, 796-800. [3] Grigorenko K.S., Makarenko N.I., Morozov E.G., Tarakanov R.Yu., and Frey D.I. Stratified flows and internal waves in the Central West Atlantic, J. Physics: Conf. Series, 2016, 722, 012011.

New media technologies and mass media reform processes

Directory of Open Access Journals (Sweden)

Tomić Boban

2017-01-01

Full Text Available This paper reviews and assesses the chances for survival and development of the media in Serbia and ib the region, from the perspective of new information and communication technologies (ICT applied in media business. In the paper theoretical method is used and harmonized with the needs of describing the problems and the observed processes and phenomena, as well as empirical method which is used for collecting and interpreting concrete facts and data on the observed processes and phenomena. The starting point lies in the fact that modern media is definitely, more and more, dependent on new technologies. A part of the new technologies is used in the process of collecting, selecting and editing media content, while the other part of the technology is used in the process of dissemination and propulsion of media content to the mass audience, and also in the feedback function as well. The technology revolution, which we describe, started with mp3, jpg and avi files, and continues with internet broadcasting, social networks, cloud technologies and new digital platforms which are used by today's media for distribution of media content. The particularity of the media in the region lies in the fact that they operating in the societes with delay of political and economic transition, so all the productive resources of society, due to this backlog, are slower adapted to the new conditions of business in the digital era. The consequences that have arisen from such dynamics of development make many media in Serbia and the region quite dysfunctional, especially those who were exposed during this transition to long-standing legal, economic and program crises. That is why most of the existing media in Serbia, especially small ones, are unprepared for modernization and they are not ready for re-modeling in accordance with the new technological circumstances.

Effect of media use on HIV/AIDS-related knowledge and condom use in sub-Saharan Africa: a cross-sectional study.

Science.gov (United States)

Jung, Minsoo; Arya, Monisha; Viswanath, Kasisomayajula

2013-01-01

It is known that the level of HIV/AIDS-related knowledge and the degree of condom use varies by socioeconomic status (SES). However, there is limited research on the effect of mass media use on HIV/AIDS-related cognitive and behavioral outcomes in low-income countries and how it might influence the association between SES and HIV-related outcomes. We investigated the moderating effect of media use on the relationship between SES and HIV/AIDS-related knowledge and condom use in sub-Saharan Africa in terms of communication inequalities. Cross-sectional data from the Demographic Health Surveys from 13 sub-Saharan countries (2004-10) were pooled. Gender-stratified multivariable poisson regression of 151,209 women and 68,890 men were used to calculate adjusted relative ratios and 95% confidence intervals for the associations between SES, media use, HIV-related outcomes, and condom use. We found significant disparities in mass media use among people from different SES groups as well as among countries. Education and wealth are strongly and positively associated with awareness of HIV/AIDS and knowledge about transmission and prevention of HIV/AIDS and are significantly associated with condom use. These associations are attenuated when the use of various types of mass media is added to the models, with newspapers showing the strongest effect. The findings of this study suggest that media use has the potential to blunt the impact of socioeconomic status though not completely eliminate it. Thus, we need to pay attention to reducing communication inequalities among social groups and countries to moderate the effect of wealth and SES on HIV/AIDS.

Effect of media use on HIV/AIDS-related knowledge and condom use in sub-Saharan Africa: a cross-sectional study.

Directory of Open Access Journals (Sweden)

Minsoo Jung

Full Text Available It is known that the level of HIV/AIDS-related knowledge and the degree of condom use varies by socioeconomic status (SES. However, there is limited research on the effect of mass media use on HIV/AIDS-related cognitive and behavioral outcomes in low-income countries and how it might influence the association between SES and HIV-related outcomes. We investigated the moderating effect of media use on the relationship between SES and HIV/AIDS-related knowledge and condom use in sub-Saharan Africa in terms of communication inequalities. Cross-sectional data from the Demographic Health Surveys from 13 sub-Saharan countries (2004-10 were pooled. Gender-stratified multivariable poisson regression of 151,209 women and 68,890 men were used to calculate adjusted relative ratios and 95% confidence intervals for the associations between SES, media use, HIV-related outcomes, and condom use. We found significant disparities in mass media use among people from different SES groups as well as among countries. Education and wealth are strongly and positively associated with awareness of HIV/AIDS and knowledge about transmission and prevention of HIV/AIDS and are significantly associated with condom use. These associations are attenuated when the use of various types of mass media is added to the models, with newspapers showing the strongest effect. The findings of this study suggest that media use has the potential to blunt the impact of socioeconomic status though not completely eliminate it. Thus, we need to pay attention to reducing communication inequalities among social groups and countries to moderate the effect of wealth and SES on HIV/AIDS.

[Media for 21st century--towards human communication media].

Science.gov (United States)

Harashima, H

2000-05-01

Today, with the approach of the 21st century, attention is focused on multi-media communications combining computer, visual and audio technologies. This article discusses the communication media target and the technological problems constituting the nucleus of multi-media. The communication media is becoming an environment from which no one can escape. Since the media has such a great power, what is needed now is not to predict the future technologies, but to estimate the future world and take to responsibility for future environments.

Media Ecology

Directory of Open Access Journals (Sweden)

Marina Ašković

2015-05-01

Full Text Available Does the trend in which electronic media are gradually becoming extension of human body have to move towards full enslavement of a human and his personality, or the same human will unpredictably, with the aid of his personal media literacy, exit the whirls of media and technological censorships? Personality crisis is closely related to the crisis of language no matter how contradicted to global ideology of transnational transhumanism it may seem. Considering the fact that recent media presentations of the world are based on commercialization of environmentalism, philosophical and aesthetic thought appears as an important subject of ecology. As media mediates, the scenery of civilized living increasingly becomes more appealing even though it derives from commercial and political background. Consequently, the future of humanity depends by large on the philosophy of media. Media have to truly ecologise returning the humanum to its essence making it into the extension of the natural world.

Media Education and Media Criticism in the Educational Process in Russia

Science.gov (United States)

Fedorov, Alexander; Levitskaya, Anastasia

2017-01-01

Media criticism and media education have a lot in common. For example, both media education and media criticism attach great importance to the development of analytical thinking of the audience. Indeed, one of the most important tasks of media education is precisely to teach the audience not only to analyze media texts of any types, but also to…

Geographic Media Literacy

Science.gov (United States)

Lukinbeal, Chris

2014-01-01

While the use of media permeates geographic research and pedagogic practice, the underlying literacies that link geography and media remain uncharted. This article argues that geographic media literacy incorporates visual literacy, information technology literacy, information literacy, and media literacy. Geographic media literacy is the ability…

SOCIAL MEDIA SECURITY

Science.gov (United States)

RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeVISITORS AND PERSONNELSOCIAL MEDIA SECURITY FAQ on Security for Social Media Due to the widespread use of

Implementing the Keele stratified care model for patients with low back pain: an observational impact study.

Science.gov (United States)

Bamford, Adrian; Nation, Andy; Durrell, Susie; Andronis, Lazaros; Rule, Ellen; McLeod, Hugh

2017-02-03

The Keele stratified care model for management of low back pain comprises use of the prognostic STarT Back Screening Tool to allocate patients into one of three risk-defined categories leading to associated risk-specific treatment pathways, such that high-risk patients receive enhanced treatment and more sessions than medium- and low-risk patients. The Keele model is associated with economic benefits and is being widely implemented. The objective was to assess the use of the stratified model following its introduction in an acute hospital physiotherapy department setting in Gloucestershire, England. Physiotherapists recorded data on 201 patients treated using the Keele model in two audits in 2013 and 2014. To assess whether implementation of the stratified model was associated with the anticipated range of treatment sessions, regression analysis of the audit data was used to determine whether high- or medium-risk patients received significantly more treatment sessions than low-risk patients. The analysis controlled for patient characteristics, year, physiotherapists' seniority and physiotherapist. To assess the physiotherapists' views on the usefulness of the stratified model, audit data on this were analysed using framework methods. To assess the potential economic consequences of introducing the stratified care model in Gloucestershire, published economic evaluation findings on back-related National Health Service (NHS) costs, quality-adjusted life years (QALYs) and societal productivity losses were applied to audit data on the proportion of patients by risk classification and estimates of local incidence. When the Keele model was implemented, patients received significantly more treatment sessions as the risk-rating increased, in line with the anticipated impact of targeted treatment pathways. Physiotherapists were largely positive about using the model. The potential annual impact of rolling out the model across Gloucestershire is a gain in approximately 30

Stratifying patients with peripheral neuropathic pain based on sensory profiles

DEFF Research Database (Denmark)

Vollert, Jan; Maier, Christoph; Attal, Nadine

2017-01-01

In a recent cluster analysis, it has been shown that patients with peripheral neuropathic pain can be grouped into 3 sensory phenotypes based on quantitative sensory testing profiles, which are mainly characterized by either sensory loss, intact sensory function and mild thermal hyperalgesia and...... populations that need to be screened to reach a subpopulation large enough to conduct a phenotype-stratified study. The most common phenotype in diabetic polyneuropathy was sensory loss (83%), followed by mechanical hyperalgesia (75%) and thermal hyperalgesia (34%, note that percentages are overlapping...

ANALISIS CATEGORY ADVERTISING EXPENDITURE DAN CONSUMER MEDIA HABIT DI MEDIA TELEVISI DAN MEDIA CETAK

Directory of Open Access Journals (Sweden)

Zifwen Zifwen

2011-08-01

Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 The purpose of the study is to identify the category of advertising expenditure and media habit on media advertising, especially on television and print ad such as newspapers, magazines and tabloids. The Data were collected  from Nielsen Media Research (NMR data base from a number of cities in Indonesia, such as Jakarta,Surabaya, Bandung, Semarang, Surabaya, Yogyakarta, Bali, Medan,Palembang and Makassar. There are three different type of data used to acquire the secondary data for the study: (1  Telescope (data collected for rating analysis January 1st, 2005 to March 31st, 2005, (2 Print scope (data collected from the readership of magazines, tabloids and newspaper January 1st, 2004 to December 31st, 2004 and (3 Ad quest (data collected from advertising expenditure for all categories. The data were collected, calculated and analyzed from January 1st, 2002 to December 31st, 2004. The purpose of the study is to uncover the trend of advertising budget from all categories on the television and print ads, in order to describe the consumption tendency of the people within advertising media. Index analysis and Biplot were used to analyze the data. Based on the result of advertising expenditure analysis of data, showing that all categories were completely different in the utilization of the media for advertisement. Some categories used mix media to support their campaign and others used a single media. Characteristic of the categories were strongly involved in the decision making in way of choosing and using the advertising media. The result of consumer media analysis found that the people habit were completely different and unique in media consumption. Different of age, sex and social economic status can create a different habit in term of hobbies and desire within the channel, programme, newspaper, magazines and the tabloids. Finally, to create an effective and efficient advertising activity

Complex three dimensional modelling of porous media using high performance computing and multi-scale incompressible approach

Science.gov (United States)

Martin, R.; Orgogozo, L.; Noiriel, C. N.; Guibert, R.; Golfier, F.; Debenest, G.; Quintard, M.

2013-05-01

In the context of biofilm growth in porous media, we developed high performance computing tools to study the impact of biofilms on the fluid transport through pores of a solid matrix. Indeed, biofilms are consortia of micro-organisms that are developing in polymeric extracellular substances that are generally located at a fluid-solid interfaces like pore interfaces in a water-saturated porous medium. Several applications of biofilms in porous media are encountered for instance in bio-remediation methods by allowing the dissolution of organic pollutants. Many theoretical studies have been done on the resulting effective properties of these modified media ([1],[2], [3]) but the bio-colonized porous media under consideration are mainly described following simplified theoretical media (stratified media, cubic networks of spheres ...). Therefore, recent experimental advances have provided tomography images of bio-colonized porous media which allow us to observe realistic biofilm micro-structures inside the porous media [4]. To solve closure system of equations related to upscaling procedures in realistic porous media, we solve the velocity field of fluids through pores on complex geometries that are described with a huge number of cells (up to billions). Calculations are made on a realistic 3D sample geometry obtained by X micro-tomography. Cell volumes are coming from a percolation experiment performed to estimate the impact of precipitation processes on the properties of a fluid transport phenomena in porous media [5]. Average permeabilities of the sample are obtained from velocities by using MPI-based high performance computing on up to 1000 processors. Steady state Stokes equations are solved using finite volume approach. Relaxation pre-conditioning is introduced to accelerate the code further. Good weak or strong scaling are reached with results obtained in hours instead of weeks. Factors of accelerations of 20 up to 40 can be reached. Tens of geometries can now be

Two-phase pressurized thermal shock investigations using a 3D two-fluid modeling of stratified flow with condensation

International Nuclear Information System (INIS)

Yao, W.; Coste, P.; Bestion, D.; Boucker, M.

2003-01-01

In this paper, a local 3D two-fluid model for a turbulent stratified flow with/without condensation, which can be used to predict two-phase pressurized thermal shock, is presented. A modified turbulent K- model is proposed with turbulence production induced by interfacial friction. A model of interfacial friction based on a interfacial sublayer concept and three interfacial heat transfer models, namely, a model based on the small eddies controlled surface renewal concept (HDM, Hughes and Duffey, 1991), a model based on the asymptotic behavior of the Eddy Viscosity (EVM), and a model based on the Interfacial Sublayer concept (ISM) are implemented into a preliminary version of the NEPTUNE code based on the 3D module of the CATHARE code. As a first step to apply the above models to predict the two-phase thermal shock, the models are evaluated by comparison of calculated profiles with several experiments: a turbulent air-water stratified flow without interfacial heat transfer; a turbulent steam-water stratified flow with condensation; turbulence induced by the impact of a water jet in a water pool. The prediction results agree well with the experimental data. In addition, the comparison of three interfacial heat transfer models shows that EVM and ISM gave better prediction results while HDM highly overestimated the interfacial heat transfers compared to the experimental data of a steam water stratified flow

Media Culture and Media Education in Modern School

Science.gov (United States)

Tolic, Mirela

2011-01-01

Culture is no longer conceivable without the media and/or new phenomena called. "Cyber" culture. The article discusses issues in what respect the different media, like TV, film and Internet are with different cultures, how it changes everyday life under influence of various forms of sophisticated communications media and what…

Post Media Literacy: Menyaksikan Kuasa Media Bersama Michel Foucault

Directory of Open Access Journals (Sweden)

Iswandi Syahputra

2017-01-01

Full Text Available This article would like to present Michel Foucault’s idea concerning Knowledge and Power in media industry. As a contemporary intellectual, Foucault’s thought has a unique style of postmodernism. His thought had gone beyond traditional critical theory whose trying to disclose the relation of power and economic behind the ideology of media. Foucault’s thought had given new perspective in understanding how the media produce truth under tightly control process into something that seems normal. With the assumption of media has the power to create mass culture, which has to be studied critically by media literacy approach, Foucault’s thought had given new space of discursive. An alternative thought on how to estimate the work of mass media as supervisor of truth and creator of information trough normalization practice.

Locative media

CERN Document Server

Wilken, Rowan

2014-01-01

Not only is locative media one of the fastest growing areas in digital technology, but questions of location and location-awareness are increasingly central to our contemporary engagements with online and mobile media, and indeed media and culture generally. This volume is a comprehensive account of the various location-based technologies, services, applications, and cultures, as media, with an aim to identify, inventory, explore, and critique their cultural, economic, political, social, and policy dimensions internationally. In particular, the collection is organized around the perception that the growth of locative media gives rise to a number of crucial questions concerning the areas of culture, economy, and policy.

A modified stratified model for the 3C 273 jet

International Nuclear Information System (INIS)

Liu Wenpo; Shen Zhiqiang

2009-01-01

We present a modified stratified jet model to interpret the observed spectral energy distributions of knots in the 3C 273 jet. Based on the hypothesis of the single index of the particle energy spectrum at injection and identical emission processes among all the knots, the observed difference of spectral shape among different 3C 273 knots can be understood as a manifestation of the deviation of the equivalent Doppler factor of stratified emission regions in an individual knot from a characteristic one. The summed spectral energy distributions of all ten knots in the 3C 273 jet can be well fitted by two components: a low-energy component (radio to optical) dominated by synchrotron radiation and a high-energy component (UV, X-ray and γ-ray) dominated by inverse Compton scattering of the cosmic microwave background. This gives a consistent spectral index of α = 0.88 (S v ∝ v -α ) and a characteristic Doppler factor of 7.4. Assuming the average of the summed spectrum as the characteristic spectrum of each knot in the 3C 273 jet, we further get a distribution of Doppler factors. We discuss the possible implications of these results for the physical properties in the 3C 273 jet. Future GeV observations with GLAST could separate the γ-ray emission of 3C 273 from the large scale jet and the small scale jet (i.e. the core) through measuring the GeV spectrum.

Development of a natural gas stratified charge rotary engine

Energy Technology Data Exchange (ETDEWEB)

Sierens, R.; Verdonck, W.

1985-01-01

A water model has been used to determine the positions of separate inlet ports for a natural gas, stratified charge rotary engine. The flow inside the combustion chamber (mainly during the induction period) has been registered by a film camera. From these tests the best locations of the inlet ports have been obtained, a prototype of this engine has been built by Audi NSU and tested in the laboratories of the university of Gent. The results of these tests, for different stratification configurations, are given. These results are comparable with the best results obtained by Audi NSU for a homogeneous natural gas rotary engine.

Media's contribution to sexual knowledge, attitudes, and behaviors for adolescents and young adults in three Asian cities.

Science.gov (United States)

Lou, Chaohua; Cheng, Yan; Gao, Ersheng; Zuo, Xiayun; Emerson, Mark R; Zabin, Laurie S

2012-03-01

Evidence in western countries indicates that the media have associations with adolescents' and young people's sexual behavior that may be as important as family, school, and peers. In this new study of Asian adolescents and young adults in the three cities of Hanoi, Shanghai, and Taipei, the associations between exposure to sexual content in the media and adolescents' and young adults' sex-related knowledge, attitudes, and behaviors are explored in societies with traditional Confucian culture, but at different stages in the process of modernization. The data are from a questionnaire-based cross-sectional study conducted from 2006 to 2007, where a sample of 17,016 adolescents and young adults aged 15-24 years from Shanghai, Hanoi, and Taipei completed face-to-face interviews coupled with computer-assisted self-interviews for sensitive questions. For the objectives of this article, analysis was restricted to the 16,554 unmarried respondents. Exposure to sexual content in the mass media (including the Internet and traditional media), pornographic videos, and a preference for western/Asian movies/videos were the main media influence measures. Sex-related knowledge, premarital sexual permissiveness (PSP), and sex-related behaviors were the main outcome measures. The impact of each of four contexts including family, peer, school, and media on sex-related knowledge, attitudes, and behaviors were assessed using multiple linear regression stratified by gender and city, controlling for age, urban/rural residence, education, and economic status. The change in adjusted R(2) from the multiple linear regression analysis was adopted to indicate the contribution of family, peer, school, and media variables to respondents' sex-related knowledge, attitudes, and behaviors. The contextual factors, including family, peer, school, and media, explained 30%-50% of the variance in sex-related knowledge, 8%-22% of the variance in PSP, and 32%-41% of the variance in sex-related behaviors

On Media Education

Science.gov (United States)

Fedorov, Alexander

2008-01-01

This monograph analyzes the theory and practice of media education and media literacy. The book also includes the list of Russian media education literature and addresses of websites of the associations for media education.

PHOTOSPHERIC EMISSION FROM STRATIFIED JETS

International Nuclear Information System (INIS)

Ito, Hirotaka; Nagataki, Shigehiro; Ono, Masaomi; Lee, Shiu-Hang; Mao, Jirong; Yamada, Shoichi; Pe'er, Asaf; Mizuta, Akira; Harikae, Seiji

2013-01-01

We explore photospheric emissions from stratified two-component jets, wherein a highly relativistic spine outflow is surrounded by a wider and less relativistic sheath outflow. Thermal photons are injected in regions of high optical depth and propagated until the photons escape at the photosphere. Because of the presence of shear in velocity (Lorentz factor) at the boundary of the spine and sheath region, a fraction of the injected photons are accelerated using a Fermi-like acceleration mechanism such that a high-energy power-law tail is formed in the resultant spectrum. We show, in particular, that if a velocity shear with a considerable variance in the bulk Lorentz factor is present, the high-energy part of observed gamma-ray bursts (GRBs) photon spectrum can be explained by this photon acceleration mechanism. We also show that the accelerated photons might also account for the origin of the extra-hard power-law component above the bump of the thermal-like peak seen in some peculiar bursts (e.g., GRB 090510, 090902B, 090926A). We demonstrate that time-integrated spectra can also reproduce the low-energy spectrum of GRBs consistently using a multi-temperature effect when time evolution of the outflow is considered. Last, we show that the empirical E p -L p relation can be explained by differences in the outflow properties of individual sources

Economic viability of Stratified Medicine concepts: An investor perspective on drivers and conditions that favour using Stratified Medicine approaches in a cost-contained healthcare environment.

Science.gov (United States)

Fugel, Hans-Joerg; Nuijten, Mark; Postma, Maarten

2016-12-25

Stratified Medicine (SM) is becoming a natural result of advances in biomedical science and a promising path for the innovation-based biopharmaceutical industry to create new investment opportunities. While the use of biomarkers to improve R&D efficiency and productivity is very much acknowledged by industry, much work remains to be done to understand the drivers and conditions that favour using a stratified approach to create economically viable products and to justify the investment in SM interventions as a stratification option. In this paper we apply a decision analytical methodology to address the economic attractiveness of different SM development options in a cost-contained healthcare environment. For this purpose, a hypothetical business case in the oncology market has been developed considering four feasible development scenarios. The article outlines the effects of development time and time to peak sales as key economic value drivers influencing profitability of SM interventions under specific conditions. If regulatory and reimbursement challenges can be solved, decreasing development time and enhancing early market penetration would most directly improve the economic attractiveness of SM interventions. Appropriate tailoring of highly differentiated patient subgroups is the prerequisite to leverage potential efficiency gains in the R&D process. Also, offering a better targeted and hence ultimately more cost-effective therapy at reimbursable prices will facilitate time to market access and allow increasing market share gains within the targeted populations. Copyright © 2016 Elsevier B.V. All rights reserved.

Homogeneous and Stratified Liquid-Liquid Flow Effect of a Viscosity Reducer: I. Comparison in parallel plates for heavy crude

Directory of Open Access Journals (Sweden)

E. J. Suarez-Dominguez

2016-12-01

Full Text Available Production of heavy crude oil in Mexico, and worldwide, is increasing which has led to the application of different methods to reduce viscosity or to enhance transport through stratified flow to continue using the existing infrastructures. In this context, injecting a viscosity improver that does not mix completely with the crude, establishes a liquid-liquid stratified flow. On the basis of a parallel plates model, comparing the increase of flow that occurs in the one-phase case which assumes a complete mixture between the crude and the viscosity improver against another stratified liquid-liquid (no mixing between the oil and compared improver; it was found that in both cases there is a flow increase for the same pressure drop with a maximum for the case in which the flow improver is between the plates and the crude.

Energy Cascade from Internal Modes in Non-uniformly Stratified Fluid through Excitation of Superharmonic Disturbances

Science.gov (United States)

Sutherland, B. R.

2016-02-01

It is well established that two-dimensional internal plane waves and modes in uniformly stratified fluid efficiently transfer energy to smaller scale waves and ultimately turbulent mixing through parametric subharmonic instability (PSI). The numerical simulations of MacKinnon & Winters (GRL 2005) predicted PSI should act efficiently to disrupt the internal tide. However, while in situ observations showed the presence of PSI, it was not found to be appreciable. One reason for the discrepancy between simulations and observations is that the former examined an internal mode in uniformly stratified fluid whereas, in reality, the internal tide exists in non-uniform stratification and is manifest as sinusoidal oscillations of the thermocline. Through theory supported by numerical simulations, it is shown that internal modes in non-uniform stratification immediately excite superharmonics, not subharmonic disturbances. These have double the horizontal wavenumber and double the frequency of the parent mode and hence move with the same horizontal phase speed of the parent mode. As the disturbances grow in amplitude, however, they interact with the parent mode generating small-scale vertically propagating internal waves within the strongly stratified layer. The occurrence of PSI over very long times can occur, as in the simulations of Hazewinkel and Winters (JPO 2011). However, a comprehensive understanding of the energy cascade from the internal tide to small scales must consider the evolution of excited superharmonic disturbances.

More Media, More People—On Social & Multimodal Media Intelligence

OpenAIRE

Degerstedt, Lars; Pelle, Snickars

2017-01-01

The purpose of this article is to address some challenges facing media intelligence in general, and competitive intelligence in particular within an altered information landscape. To understand this new situation, the notion of social and multimodal media intelligence are introduced. With cases taken primarily from the Swedish media intelligence sector, we argue that data driven media intelligence today needs to pay increasing attention to new forms of (A.) crowd-oriented and (B.) multimedia-...

Visualization periodic flows in a continuously stratified fluid.

Science.gov (United States)

Bardakov, R.; Vasiliev, A.

2012-04-01

To visualize the flow pattern of viscous continuously stratified fluid both experimental and computational methods were developed. Computational procedures were based on exact solutions of set of the fundamental equations. Solutions of the problems of flows producing by periodically oscillating disk (linear and torsion oscillations) were visualized with a high resolutions to distinguish small-scale the singular components on the background of strong internal waves. Numerical algorithm of visualization allows to represent both the scalar and vector fields, such as velocity, density, pressure, vorticity, stream function. The size of the source, buoyancy and oscillation frequency, kinematic viscosity of the medium effects were traced in 2D an 3D posing problems. Precision schlieren instrument was used to visualize the flow pattern produced by linear and torsion oscillations of strip and disk in a continuously stratified fluid. Uniform stratification was created by the continuous displacement method. The buoyancy period ranged from 7.5 to 14 s. In the experiments disks with diameters from 9 to 30 cm and a thickness of 1 mm to 10 mm were used. Different schlieren methods that are conventional vertical slit - Foucault knife, vertical slit - filament (Maksoutov's method) and horizontal slit - horizontal grating (natural "rainbow" schlieren method) help to produce supplementing flow patterns. Both internal wave beams and fine flow components were visualized in vicinity and far from the source. Intensity of high gradient envelopes increased proportionally the amplitude of the source. In domains of envelopes convergence isolated small scale vortices and extended mushroom like jets were formed. Experiments have shown that in the case of torsion oscillations pattern of currents is more complicated than in case of forced linear oscillations. Comparison with known theoretical model shows that nonlinear interactions between the regular and singular flow components must be taken

Investigations on flow reversal in stratified horizontal flow

International Nuclear Information System (INIS)

Staebler, T.; Meyer, L.; Schulenberg, T.; Laurien, E.

2005-01-01

The phenomena of flow reversal in stratified flows are investigated in a horizontal channel with application to the Emergency Core Cooling System (ECCS) in Pressurized Water Reactors (PWR). In case of a Loss-of-Coolant-Accident (LOCA), coolant can be injected through a secondary pipe within the feeding line of the primary circuit, the so called hot leg, counter-currently to the steam flow. It is essential that the coolant reaches the reactor core to prevent overheating. Due to high temperatures in such accident scenarios, steam is generated in the core, which escapes from the reactor vessel through the hot leg. In case of sufficiently high steam flow rates, only a reduced amount of coolant or even no coolant will be delivered to the reactor core. The WENKA test facility at the Institute for Nuclear and Energy Technologies (IKET) at Forschungszentrum Karlsruhe is capable to investigate the fluid dynamics of two-phase flows in such scenarios. Water and air flow counter-currently in a horizontal channel made of clear acrylic glass to allow full optical access. Flow rates of water and air can be varied independently within a wide range. Once flow reversal sets in, a strong hysteresis effect must be taken into account. This was quantified during the present investigations. Local experimental data are needed to expand appropriate models on flow reversal in horizontal two-phase flow and to include them into numerical codes. Investigations are carried out by means of Particle Image Velocimetry (PIV) to obtain local flow velocities without disturbing the flow. Due to the wavy character of the flow, strong reflections at the interfacial area must be taken into account. Using fluorescent particles and an optical filter allows eliminating the reflections and recording only the signals of the particles. The challenges in conducting local investigations in stratified wavy flows by applying optical measurement techniques are discussed. Results are presented and discussed allowing

Experimental investigation and CFD simulation of horizontal stratified two-phase flow phenomena

International Nuclear Information System (INIS)

Vallee, Christophe; Hoehne, Thomas; Prasser, Horst-Michael; Suehnel, Tobias

2008-01-01

For the investigation of stratified two-phase flow, two horizontal channels with rectangular cross-section were built at Forschungszentrum Dresden-Rossendorf (FZD). The channels allow the investigation of air/water co-current flows, especially the slug behaviour, at atmospheric pressure and room temperature. The test-sections are made of acrylic glass, so that optical techniques, like high-speed video observation or particle image velocimetry (PIV), can be applied for measurements. The rectangular cross-section was chosen to provide better observation possibilities. Moreover, dynamic pressure measurements were performed and synchronised with the high-speed camera system. CFD post-test simulations of stratified flows were performed using the code ANSYS CFX. The Euler-Euler two fluid model with the free surface option was applied on grids of minimum 4 x 10 5 control volumes. The turbulence was modelled separately for each phase using the k-ω-based shear stress transport (SST) turbulence model. The results compare very well in terms of slug formation, velocity, and breaking. The qualitative agreement between calculation and experiment is encouraging and shows that CFD can be a useful tool in studying horizontal two-phase flow

Experimental investigation and CFD simulation of horizontal stratified two-phase flow phenomena

International Nuclear Information System (INIS)

Vallee, Christophe; Hohne, Thomas; Prasser, Horst-Michael; Suhnel, Tobias

2007-01-01

For the investigation of stratified two-phase flow, two horizontal channels with rectangular cross-section were built at Forschungszentrum Rossendorf. The channels allow the investigation of air/water co-current flows, especially the slug behaviour, at atmospheric pressure and room temperature. The test-sections are made of acrylic glass, so that optical techniques, like high-speed video observation or particle image velocimetry (PIV), can be applied for measurements. The rectangular cross-section was chosen to provide better observation possibilities. Moreover, dynamic pressure measurements were performed and synchronized with the high-speed camera system. CFD post test simulations of stratified flows were performed using the code ANSYS CFX. The Euler- Euler two fluid model with the free surface option was applied on grids of minimum 4.10 5 control volumes. The turbulence was modelled separately for each phase using the k-ω based shear stress transport (SST) turbulence model. The results compare very well in terms of slug formation, velocity, and breaking. The qualitative agreement between calculation and experiment is encouraging and shows that CFD can be a useful tool in studying horizontal two-phase flow. (authors)

Experimental investigation and CFD simulation of horizontal stratified two-phase flow phenomena

Energy Technology Data Exchange (ETDEWEB)

Vallee, Christophe [Forschungszentrum Dresden-Rossendorf e.V., Dresden (Germany)], E-mail: c.vallee@fzd.de; Hoehne, Thomas; Prasser, Horst-Michael; Suehnel, Tobias [Forschungszentrum Dresden-Rossendorf e.V., Dresden (Germany)

2008-03-15

For the investigation of stratified two-phase flow, two horizontal channels with rectangular cross-section were built at Forschungszentrum Dresden-Rossendorf (FZD). The channels allow the investigation of air/water co-current flows, especially the slug behaviour, at atmospheric pressure and room temperature. The test-sections are made of acrylic glass, so that optical techniques, like high-speed video observation or particle image velocimetry (PIV), can be applied for measurements. The rectangular cross-section was chosen to provide better observation possibilities. Moreover, dynamic pressure measurements were performed and synchronised with the high-speed camera system. CFD post-test simulations of stratified flows were performed using the code ANSYS CFX. The Euler-Euler two fluid model with the free surface option was applied on grids of minimum 4 x 10{sup 5} control volumes. The turbulence was modelled separately for each phase using the k-{omega}-based shear stress transport (SST) turbulence model. The results compare very well in terms of slug formation, velocity, and breaking. The qualitative agreement between calculation and experiment is encouraging and shows that CFD can be a useful tool in studying horizontal two-phase flow.

A Fast MHD Code for Gravitationally Stratified Media using ...

Indian Academy of Sciences (India)

namic (MHD) algorithms are important for numerical modelling of highly .... include OpenMP-style pragma-based programming, e.g., developed by PGI, HMPP, .... Thus, the formula (10) returns the one-dimensional index for a field point. A.

Improved patient selection by stratified surgical intervention

DEFF Research Database (Denmark)

Wang, Miao; Bünger, Cody E; Li, Haisheng

2015-01-01

BACKGROUND CONTEXT: Choosing the best surgical treatment for patients with spinal metastases remains a significant challenge for spine surgeons. There is currently no gold standard for surgical treatments. The Aarhus Spinal Metastases Algorithm (ASMA) was established to help surgeons choose...... the most appropriate surgical intervention for patients with spinal metastases. PURPOSE: The purpose of this study was to evaluate the clinical outcome of stratified surgical interventions based on the ASMA, which combines life expectancy and the anatomical classification of patients with spinal metastases...... survival times in the five surgical groups determined by the ASMA were 2.1 (TS 0-4, TC 1-7), 5.1 (TS 5-8, TC 1-7), 12.1 (TS 9-11, TC 1-7 or TS 12-15, TC 7), 26.0 (TS 12-15, TC 4-6), and 36.0 (TS 12-15, TC 1-3) months. The 30-day mortality rate was 7.5%. Postoperative neurological function was maintained...

Experimental study of unsteady thermally stratified flow

International Nuclear Information System (INIS)

Lee, Sang Jun; Chung, Myung Kyoon

1985-01-01

Unsteady thermally stratified flow caused by two-dimensional surface discharge of warm water into a oblong channel was investigated. Experimental study was focused on the rapidly developing thermal diffusion at small Richardson number. The basic objectives were to study the interfacial mixing between a flowing layer of warm water and an underlying body of cold water and to accumulate experimental data to test computational turbulence models. Mean velocity field measurements were carried out by using NMR-CT(Nuclear Magnetic Resonance-Computerized Tomography). It detects quantitative flow image of any desired section in any direction of flow in short time. Results show that at small Richardson number warm layer rapidly penetrates into the cold layer because of strong turbulent mixing and instability between the two layers. It is found that the transfer of heat across the interface is more vigorous than that of momentum. It is also proved that the NMR-CT technique is a very valuable tool to measure unsteady three dimensional flow field. (Author)

The acceptability among health researchers and clinicians of social media to translate research evidence to clinical practice: mixed-methods survey and interview study.

Science.gov (United States)

Tunnecliff, Jacqueline; Ilic, Dragan; Morgan, Prue; Keating, Jennifer; Gaida, James E; Clearihan, Lynette; Sadasivan, Sivalal; Davies, David; Ganesh, Shankar; Mohanty, Patitapaban; Weiner, John; Reynolds, John; Maloney, Stephen

2015-05-20

Establishing and promoting connections between health researchers and health professional clinicians may help translate research evidence to clinical practice. Social media may have the capacity to enhance these connections. The aim of this study was to explore health researchers' and clinicians' current use of social media and their beliefs and attitudes towards the use of social media for communicating research evidence. This study used a mixed-methods approach to obtain qualitative and quantitative data. Participation was open to health researchers and clinicians. Data regarding demographic details, current use of social media, and beliefs and attitudes towards the use of social media for professional purposes were obtained through an anonymous Web-based survey. The survey was distributed via email to research centers, educational and clinical institutions, and health professional associations in Australia, India, and Malaysia. Consenting participants were stratified by country and role and selected at random for semistructured telephone interviews to explore themes arising from the survey. A total of 856 participants completed the questionnaire with 125 participants declining to participate, resulting in a response rate of 87.3%. 69 interviews were conducted with participants from Australia, India, and Malaysia. Social media was used for recreation by 89.2% (749/840) of participants and for professional purposes by 80.0% (682/852) of participants. Significant associations were found between frequency of professional social media use and age, gender, country of residence, and graduate status. Over a quarter (26.9%, 229/852) of participants used social media for obtaining research evidence, and 15.0% (128/852) of participants used social media for disseminating research evidence. Most participants (95.9%, 810/845) felt there was a role for social media in disseminating or obtaining research evidence. Over half of the participants (449/842, 53.3%) felt they had a

Spatial Analysis of Geothermal Resource Potential in New York and Pennsylvania: A Stratified Kriging Approach

Science.gov (United States)

Smith, J. D.; Whealton, C. A.; Stedinger, J. R.

2014-12-01

Resource assessments for low-grade geothermal applications employ available well temperature measurements to determine if the resource potential is sufficient for supporting district heating opportunities. This study used a compilation of bottomhole temperature (BHT) data from recent unconventional shale oil and gas wells, along with legacy oil, gas, and storage wells, in Pennsylvania (PA) and New York (NY). Our study's goal was to predict the geothermal resource potential and associated uncertainty for the NY-PA region using kriging interpolation. The dataset was scanned for outliers, and some observations were removed. Because these wells were drilled for reasons other than geothermal resource assessment, their spatial density varied widely. An exploratory spatial statistical analysis revealed differences in the spatial structure of the geothermal gradient data (the kriging semi-variogram and its nugget variance, shape, sill, and the degree of anisotropy). As a result, a stratified kriging procedure was adopted to better capture the statistical structure of the data, to generate an interpolated surface, and to quantify the uncertainty of the computed surface. The area was stratified reflecting different physiographic provinces in NY and PA that have geologic properties likely related to variations in the value of the geothermal gradient. The kriging prediction and the variance-of-prediction were determined for each province by the generation of a semi-variogram using only the wells that were located within that province. A leave-one-out cross validation (LOOCV) was conducted as a diagnostic tool. The results of stratified kriging were compared to kriging using the whole region to determine the impact of stratification. The two approaches provided similar predictions of the geothermal gradient. However, the variance-of-prediction was different. The stratified approach is recommended because it gave a more appropriate site-specific characterization of uncertainty

Analysis of natural convection heat transfer and flows in internally heated stratified liquid pools

International Nuclear Information System (INIS)

Gubaidullin, A.A. Jr.; Dinh, T.N.; Sehgal, B.R.

1999-01-01

In this paper, natural convection flows and heat transfer in a liquid pool, with two superposed immiscible fluid layers, are analyzed. The objective of the study is to examine the effect of interfacial hydrodynamics and to develop a method which enables energy splitting to be evaluated in a stratified liquid pool. The thermal convection, with and without an internal heat source, in a rectangular cavity with different pairs of fluids was numerically simulated by a CFD code FLOW-3D. It was found that the code performs very well for prediction of heat transfer coefficients for different conditions. The hydrodynamic coupling between immiscible layers was found to have minor, if any, impact on the natural convection heat transfer for the conditions examined. Calculated results were used to develop, and validate, a new correlation for energy splitting and for heat transfer in stratified liquid pools

PENGEMBANGAN MEDIA PEMBELAJARAN FILM ANIMASI SEBAGAI MEDIA PEMBELAJARAN KONSEP FOTOSINTESIS

Directory of Open Access Journals (Sweden)

Umrotul Hasanah

2015-11-01

Full Text Available The research aims to develop animation film as a learning media in photosynthesis concept learning and to know the results of the assessment of the learning media expert test the concept of photosynthesis animated films. This research is Research and Development (R&D. The research used questionnaire  Aspects of assessment in terms of the media covering aspects of technical quality, narration, and music/sound effects. Aspects of the assessment of the suitability of the material terms covering the material aspects of the curriculum, the clarity of the material, the order of the material, communicative, suitability of the material with the purpose of learning, material relationship with the students’ critical thinking skill, and material relationship with motivation. Media expert test against “Cahaya dan Fotosintesis” animated film made by media experts with a percentage of 80,6% with the as good category, and  92,5% are material expert excellent category. Based on the “Cahaya dan Fotosintesis” animated film expert test to students can be tasted on a limited basis, after the media deficiencies corrected. Penelitian ini bertujuan untuk mengembangkan media pembelajaran film animasi pada konsep fotosintesis dan untuk mengetahui hasil penilaian uji ahli terhadap media pembelajaran film animasi pada konsep fotosintesis. Penelitian ini merupakan penelitian research and development (R & D. Teknik pengumpulan data dengan menggunakan angket. Aspek penilaian dari segi media meliputi aspek kualitas teknik, narasi dan musik/efek suara. Aspek penilaian dari segi materi meliputi aspek kesesuaian materi dengan kurikulum, kejelasan materi, urutan materi, komunikatif, kesesuaian soal evaluasi, kesesuaian materi dengan tujuan pembelajaran, hubungan materi dengan kemampuan berpikir kritis dan hubungan materi dengan motivasi. Uji ahli terhadap media film animasi “Cahaya dan Fotosintesis” dilakukan oleh ahli media dengan perolehan persentse 80,6% dengan

Advanced liquid-cooled, turbocharged and intercooled stratified charge rotary engines for aircraft

Science.gov (United States)

Mount, Robert E.; Bartel, John; Hady, William F.

1987-01-01

Developments concerning stratified-charge rotary (SCR) engines over the past 10 years are reviewed. Aircraft engines being developed using SCR technology are shown and described, and the ability of such technology to meet general aviation engine needs is considered. Production timing and availability of SCR technology for the development of aviation rotary engines are discussed, and continuing efforts toward improving this technology, including NASA efforts, are described.

Wills Plasma Physics Department annual progress report 1982

International Nuclear Information System (INIS)

1982-01-01

Progress in the experimental program using the research tokamak TORTUS is presented. The main thrust of the program is the study of the characteristics of hydromagnetic waves in tokamak plasmas and in the use of such waves in r.f. heating. Work on runaway electron production, on wave propagation in collisional plasmas and on hydromagnetic shock wave studies is reported. Diagnostic techniques and equipment described include a laser interferometer system and techniques based on the observation of resonance fluorescence and near-resonant scattering of a laser beam from atomic species in a plasma

HUBUNGAN KETERPAPARAN MEDIA MASSA, PERAN TEMAN SEBAYA TERHADAP TINDAKAN SEKSUAL DI SMA AN-NAAS

Directory of Open Access Journals (Sweden)

rika istawati

2017-06-01

Full Text Available Masa remaja merupakan masa peralihan antara tahap anak dan dewasa dimana pada masa ini mereka sangat rentan terpapar informasi dari media massa dan teman sebaya terutama seks bebas. Data SKRRI mempunyai teman yang pernah berhubungan seksual pada usia 14-19 tahun dengan persentasi perempuan 37,7% dan laki-laki 30,9% dan Kementerian Komunikasi dan Informasi menyebut 62,1% siswa mengaku penah melakukan hubungan seks. Observasi yang di lakukan oleh peneliti di SMA AN-NAAS Pekanbaru diketahui adanya 2 siswa  yang tertangkap menyimpan dan menonton video porno di handphone dan melalui wawancara peneliti dengan 8 siswi mereka mengatakan adanya 1 siswi yang hamil diluar nikah dan 2 siswi diantaranya mengaku sering datang ketempat yang berisiko terhadap tindakan seksual. Tujuan Penelitian ini untuk mengetahui hubungan keterpaparan media massa dan peran teman sebaya terhadap tindakan seksual. Desain penelitian yang digunakan adalah cross sectional, populasi penelitian adalah seluruh siswa kelas SMA AN-NAAS Pekanbaru yaitu 123 responden. Sampel penelitian 94 orang dengan teknik stratified random sampling. Alat ukur yang digunakan adalah angket, data diolah menggunakan komputer. Analisa data secara univariat dan bivariat dengan uji chi square dengan ketentuan α (0,5. Hasil penelitian didapatkan uji statistik menunjukkan adanya hubungan keterpaparan media massa dengan tindakan seksual dimana nilai p value 0,000 < 0,05, terdapat hubungan yang bermakna antara peran teman sebaya dengan tindakan seksual, dimana p value  0,001 < 0,05. Bagi pihak sekolah diharapkan untuk meningkatkan kegiatan di sekolah seperti ekstrakurikuler dan guru membimbing serta memberi pengawasan yang ketat terhadap siswanya.   

An extension of theoretical analysis for the onset of slugging criterion in horizontal stratified air-water countercurrent flow

International Nuclear Information System (INIS)

Lee, Byung Ryung

1997-02-01

This paper presents an experimental and theoretical investigation of interfacial friction factor, wave height and transition criterion from wavy to slug flow in a long horizontal air-water countercurrent stratified flow condition. A series of experiments have been conducted in adiabatic countercurrent stratified flow with the round pipe and rectangular duct test section to develop the interfacial friction factor and the criterion of onset of slugging in horizontal air-water countercurrent stratified flow. An adiabatic semi-empirical correlation for interfacial friction factor has been developed based on the surface roughness concept. A comparison of the measured data in this study and of other investigators with the predictions of the present correlation shows that the agreement is within ±30% error, and that the present correlation is applicable to a broader range of water flow rate than the correlations of previous investigators. The theories which can calculate the wave height and criteria of onset of slug flow in a stratified wavy flow regime have been developed based on the concept of total energy conservation and also wave theory. This theoretical criteria agree better with the measured data than the other criteria available in the literature, but the criteria range about 92∼107% of the measured data. An empirical formula for the criterion has been also developed and compared with the formula in the literatures. Comparison between the measured data and the predictions of the present theory shows that the agreement is within ±8%

Social Media Reputation

DEFF Research Database (Denmark)

Etter, Michael Andreas; Ravasi, Davide; Colleoni, Elanor

motivational drivers and contextual conditions associated with the formation of narratives in traditional news media and social media influence their content, diffusion, and impact significantly. Our analysis suggests that current theories of media reputation may provide an incomplete representation......Social media enable millions of users to create and disseminate narratives about organizations that increase their public exposure and shape public perceptions. In this paper, we draw on the sociology of news production and research on computer-mediated communication to discuss how different...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....

AMAMM - All Media Are Mixed Media

DEFF Research Database (Denmark)

All Media Are Mixed Media Alle medier er blandingsmedier. Alle kunstarter er kompositte. Alle sanser er sammensatte. Alle medialiteter er miksede og mangfoldige. Alle er AMAMM. Denne påstand står centralt i ord-, billed- og medie-teoretikeren W.J.T. Mitchells forfatterskab. I hosstående bog tager...

The clinical and cost-effectiveness of stratified care for patients with sciatica: the SCOPiC randomised controlled trial protocol (ISRCTN75449581).

Science.gov (United States)

Foster, Nadine E; Konstantinou, Kika; Lewis, Martyn; Ogollah, Reuben; Dunn, Kate M; van der Windt, Danielle; Beardmore, Ruth; Artus, Majid; Bartlam, Bernadette; Hill, Jonathan C; Jowett, Sue; Kigozi, Jesse; Mallen, Christian; Saunders, Benjamin; Hay, Elaine M

2017-04-26

Sciatica has a substantial impact on patients, and is associated with high healthcare and societal costs. Although there is variation in the clinical management of sciatica, the current model of care usually involves an initial period of 'wait and see' for most patients, with simple measures of advice and analgesia, followed by conservative and/or more invasive interventions if symptoms fail to resolve. A model of care is needed that does not over-treat those with a good prognosis yet identifies patients who do need more intensive treatment to help with symptoms, and return to everyday function including work. The aim of the SCOPiC trial (SCiatica Outcomes in Primary Care) is to establish whether stratified care based on subgrouping using a combination of prognostic and clinical information, with matched care pathways, is more effective than non-stratified care, for improving time to symptom resolution in patients consulting with sciatica in primary care. We will also assess the impact of stratified care on service delivery and evaluate its cost-effectiveness compared to non-stratified care. Multicentre, pragmatic, parallel arm randomised trial, with internal pilot, cost-effectiveness analysis and embedded qualitative study. We will recruit 470 adult patients with sciatica from general practices in England and Wales, over 24 months. Patients will be randomised to stratified care or non-stratified care, and treated in physiotherapy and spinal specialist services, in participating NHS services. The primary outcome is time to first resolution of sciatica symptoms, measured on a 6-point ordered categorical scale, collected using text messaging. Secondary outcomes include physical function, pain intensity, quality of life, work loss, healthcare use and satisfaction with treatment, and will be collected using postal questionnaires at 4 and 12-month follow-up. Semi-structured qualitative interviews with a subsample of participants and clinicians will explore the

Mixing process of a binary gas in a density stratified layer

Energy Technology Data Exchange (ETDEWEB)

Takeda, Tetsuaki [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

1997-09-01

This study is to investigate the effect of natural convection on the mixing process by molecular diffusion in a vertical stratified layer of a binary fluid. There are many experimental and analytical studies on natural convection in the vertical fluid layer. However, there are few studies on natural convection with molecular diffusion in the vertical stratified layer of a binary gas. Experimental study has been performed on the combined phenomena of molecular diffusion and natural convection in a binary gas system to investigate the mixing process of the binary gas in a vertical slot consisting of one side heated and the other side cooled. The range of Rayleigh number based on the slot width was about 0 < Ra{sub d} < 7.5 x 10{sup 4}. The density change of the gas mixture and the temperature distribution in the slot was obtained and the mixing process when the heavier gas ingress into the vertical slot filled with the lighter gas from the bottom side of the slot was discussed. The experimental results showed that the mixing process due to molecular diffusion was affected significantly by the natural convection induced by the slightly temperature difference between both vertical walls even if a density difference by the binary gas is larger than that by the temperature difference. (author). 81 refs.

Cross-stratified Wood: Enigmatic Woody Debris Deposits in Warm-Polar Fluvial Sediments (Pliocene Beaufort Formation, Nunavut)

Science.gov (United States)

Davies, N. S.; Gosse, J. C.; Rybczynski, N.

2012-04-01

Woody debris has been an important sediment component and a significant geomorphic agent in pristine fluvial systems since the Devonian. In recent years a large volume of research has focussed on various aspects of the importance of woody debris within the fluvial realm; from the evolutionary significance of fossil wood accumulations in the rock record to studies of the biogeomorphological and ecological importance of woody debris in modern rivers. In this presentation we describe cross-stratified woody debris deposits comprising organic detritus from a boreal-type treeline forest that included species of pine, birch, poplar, alder, spruce, eastern cedar, and larch, in both shrub and tree form. The cross-stratified wood is an enigmatic subset of fine woody debris which, to our knowledge, has never before been described from either the global stratigraphic record or modern fluvial environments. The deposits we describe are located within the Pliocene Beaufort Formation on Meighen Island, Nunavut, Canada, at a latitude of 80°N, and are compared with other cross-stratified woody debris deposits that have been noted elsewhere in the Pliocene of the Canadian Arctic. We make the robust observation that these deposits appear to be geographically and stratigraphically restricted to polar latitudes from a period of warm climatic conditions during the Pliocene (15-20 °C warmer mean annual temperature than the present day). In this regard it is possible to speculate that the transport of large amounts of woody debris as bedload is potentially a unique feature of forested high latitude rivers. Such bedload deposition requires a large amount of woody debris with a greater density than the fluid transporting it. The softwood composition of the debris suggests that this was most likely attained by saturation and subsequent entrainment of extensive accumulations of deadwood, promoted by unusually high rates of tree mortality and low rates of bacterial decomposition arising from

An experimental investigation of stratified two-phase pipe flow at small inclinations

Energy Technology Data Exchange (ETDEWEB)

Espedal, Mikal

1998-12-31

The prediction of stratified flow is important for several industrial applications. Stratified flow experiments were carefully performed in order to investigate the performance of a typical model which uses wall friction factors based on single phase pipe flow as described above. The test facility has a 18.5 m long and 60 mm i.d. (L/D=300) acrylic test section which can be inclined between -10 {sup o} and +10 {sup o}. The liquid holdup was measured by using fast closing valves and the pressure gradients by using three differential pressure transducers. Interfacial waves were measured by thin wire conductance probes mounted in a plane perpendicular to the main flow. The experiments were performed using water and air at atmospheric pressure. The selected test section inclinations were between -3 {sup o} and +0.5 {sup o} to the horizontal plane. A large number of experiments were performed for different combinations of air and water flow rates and the rates were limited to avoid slug flow and stratified flow with liquid droplets. The pressure gradient and the liquid holdup were measured. In addition the wave probes were used to find the wave heights and the wave power spectra. The results show that the predicted pressure gradient using the standard models is approximately 30% lower than the measured value when large amplitude waves are present. When the flow is driven by the interfacial force the test section inclination has minor influence on the deviation between predicted and measured pressure gradients. Similar trends are apparent in data from the literature, although they seem to have gone unnoticed. For several data sets large spread in the predictions are observed when the model described above was used. Gas wall shear stress experiments indicate that the main cause of the deviation between measured and predicted pressure gradient and holdup resides in the modelling of the liquid wall friction term. Measurements of the liquid wall shear stress distribution

Impact of statin related media coverage on use of statins: interrupted time series analysis with UK primary care data.

Science.gov (United States)

Matthews, Anthony; Herrett, Emily; Gasparrini, Antonio; Van Staa, Tjeerd; Goldacre, Ben; Smeeth, Liam; Bhaskaran, Krishnan

2016-06-28

 To quantify how a period of intense media coverage of controversy over the risk:benefit balance of statins affected their use.  Interrupted time series analysis of prospectively collected electronic data from primary care.  Clinical Practice Research Datalink (CPRD) in the United Kingdom.  Patients newly eligible for or currently taking statins for primary and secondary cardiovascular disease prevention in each month in January 2011-March 2015.  Adjusted odds ratios for starting/stopping taking statins after the media coverage (October 2013-March 2014).  There was no evidence that the period of high media coverage was associated with changes in statin initiation among patients with a high recorded risk score for cardiovascular disease (primary prevention) or a recent cardiovascular event (secondary prevention) (odds ratio 0.99 (95% confidence interval 0.87 to 1.13; P=0.92) and 1.04 (0.92 to 1.18; P=0.54), respectively), though there was a decrease in the overall proportion of patients with a recorded risk score. Patients already taking statins were more likely to stop taking them for both primary and secondary prevention after the high media coverage period (1.11 (1.05 to 1.18; P<0.001) and 1.12 (1.04 to 1.21; P=0.003), respectively). Stratified analyses showed that older patients and those with a longer continuous prescription were more likely to stop taking statins after the media coverage. In post hoc analyses, the increased rates of cessation were no longer observed after six months.  A period of intense public discussion over the risks:benefit balance of statins, covered widely in the media, was followed by a transient rise in the proportion of people who stopped taking statins. This research highlights the potential for widely covered health stories in the lay media to impact on healthcare related behaviour. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Parents and the media: causes and consequences of parental media socialization

NARCIS (Netherlands)

Notten, N.J.W.R.

2011-01-01

Media literacy is an important part of socialization and with media use becoming ever more essential in modern society, research on parental media socialization is vital. This study proposes the intergenerational transmission of parent’s media competencies, as a specific kind of cultural

Media Literacy Bibliography.

Science.gov (United States)

Duncan, Barry

1989-01-01

Provides an up-to-date bibliography of resources available for teaching media literacy. Groups resources into the areas of media education methodology, mass media texts, general background, television, film, the news and medium of print, advertising, gender and the media, popular culture, popular music and rock video, periodicals, and…

Parenting and Digital Media.

Science.gov (United States)

Coyne, Sarah M; Radesky, Jenny; Collier, Kevin M; Gentile, Douglas A; Linder, Jennifer Ruh; Nathanson, Amy I; Rasmussen, Eric E; Reich, Stephanie M; Rogers, Jean

2017-11-01

Understanding the family dynamic surrounding media use is crucial to our understanding of media effects, policy development, and the targeting of individuals and families for interventions to benefit child health and development. The Families, Parenting, and Media Workgroup reviewed the relevant research from the past few decades. We find that child characteristics, the parent-child relationship, parental mediation practices, and parents' own use of media all can influence children's media use, their attitudes regarding media, and the effects of media on children. However, gaps remain. First, more research is needed on best practices of parental mediation for both traditional and new media. Ideally, this research will involve large-scale, longitudinal studies that manage children from infancy to adulthood. Second, we need to better understand the relationship between parent media use and child media use and specifically how media may interfere with or strengthen parent-child relationships. Finally, longitudinal research on how developmental processes and individual child characteristics influence the intersection between media and family life is needed. The majority of children's media use takes place within a wider family dynamic. An understanding of this dynamic is crucial to understanding child media use as a whole. Copyright © 2017 by the American Academy of Pediatrics.

Social Media, Traditional Media and Marketing Communication of Public Relations

DEFF Research Database (Denmark)

Khajeheian, Datis; Mirahmadi, Fereshteh

2015-01-01

Public relations are undertaking more important role in the marketing communication and advertising. The present paper reports a survey conducted in three Iranian banks’ public relations departments to understand how they use different media in their marketing communications and other related...... functions. A classification of public relations functions including fourteen functions in three categories has taken as research framework and by using a questionnaire, eight media have been asked to rank for each function, includes Television, Radio, Newspaper, Magazine, Classified Ads, Internet Websites......, Social media and finally Mobile and SMS ads. Findings show that traditional media still play a dominant role in media consumption of public relations, while new Web2.0 media consist of Mobile communications and Social networks, have never ranked better than fifth from eight. Some reasons have been argues...

The New Rich and Their Unplanned Births: Stratified Reproduction under China's Birth-planning Policy.

Science.gov (United States)

Shi, Lihong

2017-12-01

This article explores the creation and ramifications of a stratified reproductive system under China's state control of reproduction. Within this system, an emerging group of "new rich" are able to circumvent birth regulations and have unplanned births because of their financial capabilities and social networks. While China's birth-planning policy is meant to be enforced equally for all couples, the unequal access to wealth and bureaucratic power as a result of China's widening social polarization has created disparate reproductive rights and experiences. This article identifies three ways in which reproductive privileges are created. It further explores how a stratified reproductive system under state population control reinforces social polarization. While many socially marginalized couples are unable to register their unplanned children for citizenship status and social benefits, the new rich are able to legitimate their births and transfer their privilege and status to their children, thus reproducing a new generation of elites. © 2016 by the American Anthropological Association.

Media - Our friends (improving our relationship with media)

International Nuclear Information System (INIS)

Stiopol, Mihaela; Bilegan, Iosif Constantin

2000-01-01

The paper will present the principles, goals and the steps followed in establishing media relationships. It will highlight the company' s activity developed over this year within the Romanian Public Information Programme in the nuclear field, in order to establish friendly relationship with media, as well as the conclusions we have reached in performing such an activity. In this moment, the way public receives the real information has a great impact on the future development of this alternative and the role of media is an essential one. So, we consider that the utility mission is to act promptly to transmit to the public complete and honest information with the help of this important segment which is media

Media:Time card stack

NARCIS (Netherlands)

Annemarie Wennekers; Jos de Haan; Frank Huysmans

2016-01-01

Original title: Media:Tijd in kaart The Dutch spend a daily average of 8 hours 33 minutes using media. Men and people aged over 50 spend most time using media, at an average of 9 hours per day. Older media users prefer traditional media and devices over new media and modern devices. Young and

Making Media Studies

Directory of Open Access Journals (Sweden)

David Gauntlett

2015-12-01

Full Text Available This podcast is a recording of a research seminar that took place on December 3, 2015, at the University of Westminster's Communication and Media Research Institute (CAMRI. In this contribution, David Gauntlett discusses his new book, Making Media Studies, and other new work. In Making Media Studies (Peter Lang, 2015, Gauntlett proposes a vision of media studies based around doing and making – not about the acquisition of skills, as such, but an experience of building knowledge and understanding through creative hands-on engagement with all kinds of media. Gauntlett suggests that media studies scholars have failed to recognise the significance of everyday creativity – the vital drive of people to make, exchange, and learn together, supported by online networks. He argues that we should think about media in terms of conversations, inspirations, and making things happen. Media studies can be about genuine social change, he suggests, if we recognise the significance of everyday creativity, work to transform our tools, and learn to use them wisely. David Gauntlett is a Professor in the School of Media, Arts and Design at the University of Westminster, where he is also the School's Co-Director of Research. He is the author of several books, including: Creative Explorations (2007, Media, Gender and Identity: An Introduction (2nd edition 2008, Making is Connecting (2011, and Making Media Studies (2015. He has made a number of popular online resources, videos and playthings, and has pioneered creative research and workshop methods. He is external examiner for Information Experience Design at the Royal College of Art, London.

The Risk-Stratified Osteoporosis Strategy Evaluation study (ROSE)

DEFF Research Database (Denmark)

Rubin, Katrine Hass; Holmberg, Teresa; Rothmann, Mette Juel

2015-01-01

The risk-stratified osteoporosis strategy evaluation study (ROSE) is a randomized prospective population-based study investigating the effectiveness of a two-step screening program for osteoporosis in women. This paper reports the study design and baseline characteristics of the study population....... 35,000 women aged 65-80 years were selected at random from the population in the Region of Southern Denmark and-before inclusion-randomized to either a screening group or a control group. As first step, a self-administered questionnaire regarding risk factors for osteoporosis based on FRAX......(®) was issued to both groups. As second step, subjects in the screening group with a 10-year probability of major osteoporotic fractures ≥15 % were offered a DXA scan. Patients diagnosed with osteoporosis from the DXA scan were advised to see their GP and discuss pharmaceutical treatment according to Danish...

Estimation of Finite Population Mean in Multivariate Stratified Sampling under Cost Function Using Goal Programming

Directory of Open Access Journals (Sweden)

Atta Ullah

2014-01-01

Full Text Available In practical utilization of stratified random sampling scheme, the investigator meets a problem to select a sample that maximizes the precision of a finite population mean under cost constraint. An allocation of sample size becomes complicated when more than one characteristic is observed from each selected unit in a sample. In many real life situations, a linear cost function of a sample size nh is not a good approximation to actual cost of sample survey when traveling cost between selected units in a stratum is significant. In this paper, sample allocation problem in multivariate stratified random sampling with proposed cost function is formulated in integer nonlinear multiobjective mathematical programming. A solution procedure is proposed using extended lexicographic goal programming approach. A numerical example is presented to illustrate the computational details and to compare the efficiency of proposed compromise allocation.

Generation of large-scale vorticity in rotating stratified turbulence with inhomogeneous helicity: mean-field theory

Science.gov (United States)

Kleeorin, N.

2018-06-01

We discuss a mean-field theory of the generation of large-scale vorticity in a rotating density stratified developed turbulence with inhomogeneous kinetic helicity. We show that the large-scale non-uniform flow is produced due to either a combined action of a density stratified rotating turbulence and uniform kinetic helicity or a combined effect of a rotating incompressible turbulence and inhomogeneous kinetic helicity. These effects result in the formation of a large-scale shear, and in turn its interaction with the small-scale turbulence causes an excitation of the large-scale instability (known as a vorticity dynamo) due to a combined effect of the large-scale shear and Reynolds stress-induced generation of the mean vorticity. The latter is due to the effect of large-scale shear on the Reynolds stress. A fast rotation suppresses this large-scale instability.

Ageing in media: rethinking the studying of media use in later life

DEFF Research Database (Denmark)

Givskov, Cecilie

in the realms of politics and commerce – and, of course, media. Ageing populations are key drivers of media sales, especially in the areas of mobile and online media, and they are the dominant audience groups following the news. At the same time, social institutions realign their relations with (older) citizens...... characterized by chronological life phase and generational perspectives, to some extent influenced by medicalised images of old age where ageing after the 60s gets correlated with a loss of intellectual and creative resources, a decline of social life and physical health, and with regard to media, a lack...... through digital media. In spite of this inversion of the age pyramid and their significance as media users and active citizens, older people’s media use is rarely the focus of media producers or communication scholars. What research does get carried out involving older people’s media use is generally...

Turbulence and wave particle interactions in solar-terrestrial plasmas. Annual Status Report, 1 July 1983-30 June 1984

International Nuclear Information System (INIS)

Dulk, G.A.; Goldman, M.V.; Toomre, J.

1985-01-01

Activities in the following study areas are reported: (1) particle and wave processes in solar flares; (2) solar convection zone turbulence; and (3) solar radiation emission. To investigate the amplification of cyclotron maser radiation in solar flares, a radio frequency. (RF) heating model was developed for the corona surrounding the energy release site. Then nonlinear simulations of compressible convection display prominent penetration by plumes into regions of stable stratification at the base of the solar convection zone, leading to the excitation of internal gravity waves there. Lastly, linear saturation of electron-beam-driven Langmuir waves by ambient density fluctuations, nonlinear saturation by strong turbulence processes, and radiation emission mechanisms are examined. An additional section discusses solar magnetic fields and hydromagnetic waves in inhomogeneous media, and the effect of magnetic fields on stellar oscillation

Media violence in the information society in the context of media anthropology

Directory of Open Access Journals (Sweden)

N. A. Mazorenko

2014-01-01

Full Text Available The article discusses media violence as special case of deviant manifestations of the individual and collective social body. It’s stated that in the late 20th century emphasis had shifted from the sociological and ethnographic works towards a more wide format of a man and the media studies. According to the author, it was caused by the forming of the media anthropology as human­oriented paradigm of the postmodern media. The place of media violence in problematic field of the media anthropology field is defined. It’s considered as a result of the somatic transformations in the media and the cultural space of the information society. Mass media have been products of culture and social life and at the same time factors of the identity’s construction. Such characteristic properties require more conscious of morality and responsibility. Media need to understand and represent new modes of physicality / spirituality and rationality / irrationality in the media and socio­political life. Due to weakening or decline of spiritual and intellectual component in the psycho­somatic existence threatens to turn society into collective grotesque body, and media that exploit these social strain, into media spectacle, distorted and grotesque in the worst sense of the word. In this article, the method of anthropological reduction, and elements of cultural­historical and structural­functional analysis have been used.

Radiographic contrast media

International Nuclear Information System (INIS)

Golman, K.; Holtz, E.; Almen, T.

1987-01-01

Contrast media are used in diagnostic radiology to enhance the X-ray attenuation between a body structure of interest and the surrounding tissue. A detail becomes perceptible on a roentgenogram only when its contrast exceeds a minimum value in relation to the background. Small areas of interest must have higher contrast than the background. The contrast effect depends on concentration of the contrast media with the body. A high contrast media concentration difference thus gives rise to more morphological details in the radiographs. Contrast media can be divided into negative contrast media such as air and gas which attenuate X-rays less than the body tissues, and positive contrast materials which attenuate X-rays more than the body tissues. The positive contrast media all contain either iodine (atomic number 53) or barium (atomic number 56) and can be divided into water-insoluble and water-soluble contrast media

The Media Mixer

DEFF Research Database (Denmark)

Vestergaard, Vitus; Mortensen, Christian Hviid

2011-01-01

content. The media content is created by the user in the museum's physical environment, but it can be mixed with material from web archives. It is the intention that the users learn about media through participatory and creative processes with media where the borders between producing, playing......We explore how remixing and content sharing can be used as a means for user participation in a digital museum age. Remix culture is seen as a culture that allows and encourages the production of derivative works; works that are based on already existing works. This cultural practice thrives...... throughout the Internet, most notably on web 2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here the museum users can produce, deconstruct, reconstruct and finally publish and share digital media...

Mortality in perforated peptic ulcer patients after selective management of stratified poor risk cases.

Science.gov (United States)

Rahman, M Mizanur; Islam, M Saiful; Flora, Sabrina; Akhter, S Fariduddin; Hossain, Shahid; Karim, Fazlul

2007-12-01

Perforated peptic ulcer disease continues to inflict high morbidity and mortality. Although patients can be stratified according to their surgical risk, optimal management has yet to be described. In this study we demonstrate a treatment option that improves the mortality among critically ill, poor risk patients with perforated peptic ulcer disease. In our study, two series were retrospectively reviewed: group A patients (n = 522) were treated in a single surgical unit at the Dhaka Medical College Hospital, Dhaka, Bangladesh during the 1980s. Among them, 124 patients were stratified as poor risk based on age, delayed presentation, peritoneal contamination, and coexisting medical problems. These criteria were the basis for selecting a group of poor risk patients (n = 84) for minimal surgical intervention (percutaneous peritoneal drainage) out of a larger group of patients, group B (n = 785) treated at Khulna Medical College Hospital during the 1990s. In group A, 479 patients underwent conventional operative management with an operative mortality of 8.97%. Among the 43 deaths, 24 patients were >60 years of age (55.8%), 12 patients had delayed presentation (27.9%), and 7 patients were in shock or had multiple coexisting medical problems (16.2%). In group B, 626 underwent conventional operative management, with 26 deaths at a mortality rate of 4.15%. Altogether, 84 patients were stratified as poor risk and were managed with minimal surgical intervention (percutaneous peritoneal drainage) followed by conservative treatment. Three of these patients died with an operative mortality of 3.5%. Minimal surgical intervention (percutaneous peritoneal drainage) can significantly lower the mortality rate among a selected group of critically ill, poor risk patients with perforated peptic ulcer disease.

An experimental study on quenching of a radially stratified heated porous bed

International Nuclear Information System (INIS)

Nayak, Arun K.; Sehgal, Bal Raj; Stepanyan, Armen V.

2006-01-01

The quenching characteristics of a volumetrically-heated particulate bed composed of radially stratified sand layers were investigated experimentally in the POMECO facility. The sand bed simulates the corium particulate debris bed which is formed when the molten corium released from the vessel fragments in water and deposits on the cavity floor during a postulated severe accident in a light water reactor (LWR). The electrically-heated bed was quenched by water from a water column established over top of it, and later also with water coming from its bottom, which was circulating from the water overlayer through downcomers. A series of experiments were conducted to reveal the effects of the size of downcomers, and their locations in the bed, on the quenching characteristics of the radially stratified debris beds. The downcomers were found to significantly increase the bed quenching rate. To simulate the non-condensable gases generated during the MCCI, air and argon were injected from the bottom of the bed at different flow rates. The effects of gas flow rate and its properties on the quenching behaviour were observed. The results indicate that the non-condensable gas flows reduce the quenching rate significantly. The gas properties also affect the quenching characteristics

Stratifying a Risk for an Increased Variation of Airway Caliber among the Clinically Stable Asthma

Directory of Open Access Journals (Sweden)

Atsushi Hayata

2013-01-01

Conclusions: These results indicate that ACQ, %FEV1 and FENO can stratify the risk for increased variation in airway caliber among patients with stable asthma. This may help identify subjects in whom further monitoring of lung function fluctuations is indicated.

Seasonal cyclogenesis and the role of near-surface stratified layer in the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Murty, V.S.N.; Sarma, M.S.S.; Tilvi, V.

The role of the near-surface stratified layer developed due to the spread of low salinity waters under the influence of freshwater influx on the cyclogenesis over the Bay of Bengal is addressed. The seasonal variation of the Effective Oceanic Layer...

Media work as public affairs: moving beyond media savvy

DEFF Research Database (Denmark)

Trapp, Leila; Laursen, Bo

Much research exists which examines how politically-motivated organizations adapt their communication practices to suit the news media’s routines and values to gain media coverage and thereby exert political influence. The mediatization literature describes these adaptation processes as constantly...... evolving, with professional communicators exhibiting an ever-growing amount of media savvy. The purpose of this study is to gain up-to-date insights into current forms of media adaptation in political organizations through interviews with professional press contact staff in 52 Danish interest groups....... The interviews reveal that media work is considered an effective, though potentially risky, form of public affairs. Indeed, media work is said to damage, or even ruin, an organization’s lobbying efforts or relationships with political actors. The study’s key finding is that in order to deal with these risks...

Unpacking New Media Literacy

Directory of Open Access Journals (Sweden)

Der-Thanq “victor” Chen

2011-04-01

Full Text Available The 21st century has marked an unprecedented advancement of new media. New media has become so pervasive that it has penetrated into every aspect of our society. New media literacy plays an essential role for any citizen to participate fully in the 21st century society. Researchers have documented that literacy has evolved historically from classic literacy (reading-writing-understanding to audiovisual literacy to digital literacy or information literacy and recently to new media literacy. A review of literature on media literacy reveals that there is a lack of thorough analysis of unique characteristics of new media and its impacts upon the notion of new media literacy. The purpose of the study is to unpack new media literacy and propose a framework for a systematic investigation of new media literacy.

The global reproductive health market: U.S. media framings and public discourses about transnational surrogacy.

Science.gov (United States)

Markens, Susan

2012-06-01

During the first decade of the 21st century a new "dramatic story" about the growing global surrogacy industry brought renewed attention to surrogacy as a social problem and a health policy issue. This paper asks: What cultural assumptions about gender, family and the global reproductive health market are revealed in current U.S. media coverage of and public discourses about surrogacy? From a qualitative analysis of prominent news accounts of surrogacy that were published in 2008, New York Times articles and blogs published on the topic between 2006 and 2010, and over 1000 online reader comments to these articles, I identify key frames used to discursively construct and debate the international surrogacy market. This study reveals the distinct contrast between the occasions when reproductive labor is rhetorically distanced from commodification processes and when it is linked to those processes. The findings contribute to intersectional analyses of assisted reproductive practices and women's health/bodies/gametes. In particular, this study's analysis of recent media framings of and public discourses about surrogacy across the globe serves as another illustration that national/classed/racialized bodies continue to be reproductively stratified via differently gendered discourses about women, motherhood and family. Copyright © 2011 Elsevier Ltd. All rights reserved.

Media Activism and the Academy, Three Cases: Media Democracy Day, Open Media, and NewsWatch Canada

Directory of Open Access Journals (Sweden)

David Skinner

2015-12-01

Full Text Available In Canada, there is a relatively strong tradition of activist scholarship in media and communication studies. However, very little research has been undertaken on how working in the university may contextualize the ways in which academic workers participate in activist media projects. Focusing on three such projects – Media Democracy Day, Open Media, and NewsWatch Canada – this article draws upon elements of political economy and Bourdieu’s field theory to consider how the different characters of the academic and activist fields work to enable and constrain the abilities of faculty to engage with them.

Application of radial basis function in densitometry of stratified regime of liquid-gas two phase flows

International Nuclear Information System (INIS)

Roshani, G.H.; Nazemi, E.; Roshani, M.M.

2017-01-01

In this paper, a novel method is proposed for predicting the density of liquid phase in stratified regime of liquid-gas two phase flows by utilizing dual modality densitometry technique and artificial neural network (ANN) model of radial basis function (RBF). The detection system includes a 137 Cs radioactive source and two NaI(Tl) detectors for registering transmitted and scattered photons. At the first step, a Monte Carlo simulation model was utilized to obtain the optimum position for the scattering detector in dual modality densitometry configuration. At the next step, an experimental setup was designed based on obtained optimum position for detectors from simulation in order to generate the required data for training and testing the ANN. The results show that the proposed approach could be successfully applied for predicting the density of liquid phase in stratified regime of gas-liquid two phase flows with mean relative error (MRE) of less than 0.701. - Highlights: • Density of liquid phase in stratified regime of two phase flows was predicted. • Combination of dual modality densitometry technique and ANN was utilized. • Detection system includes a 137 Cs radioactive source and two NaI(Tl) detectors. • MCNP simulation was done to obtain the optimum position for the scattering detector. • An experimental setup was designed to generate the required data for training the ANN.

Kesadaran Kritis Mahasiswa Terhadap Media Sosial (Studi Deskriptif Kualitatif Literasi Media Tentang Kesadaran Kritis Mahasiswa Ilmu Komunikasi USU Terhadap Media Sosial)

OpenAIRE

Nurhaliza, Ade

2017-01-01

This study entitled “Critical Awareness of Communication Student in Social Media”. This study aimed to find out how student’s critical awareness in social media in media literacy context. The Theories used in this study are media literacy theory, critical awareness theory, new media and digital media literacy, and social media. The method used in this study is qualitative descriptive which describes the condition on the ground, reality, and the situation or some phenomenones. The result showe...

Intermediality and media change

OpenAIRE

2012-01-01

This book is about intermediality as an approach to analysing and understanding media change. Intermediality and Media Change is critical of technological determinism that characterises 'new media discourse' about the ongoing digitalization, framed as a revolution and creating sharp contrasts between old and new media. Intermediality instead emphasises paying attention to continuities between media of all types and privileges a comparative perspective on technological changes in media over ti...

Media exposure and health in Europe: Mediators and moderators of media systems

NARCIS (Netherlands)

Blom, N.; Zanden, R. van der; Buijzen, M.A.; Scheepers, P.L.H.

2016-01-01

This study examined media exposure as an explanatory factor for individual and cross-national differences in self-assessed general health. In studying media exposure, traditional media (television, radio, and newspapers) and contemporary media (internet) were separately considered. Aside from

Media violence.

Science.gov (United States)

Cantor, J

2000-08-01

Research on the effects of media violence is not well understood by the general public. Despite this fact, there is an overwhelming consensus in the scientific literature about the unhealthy effects of media violence. Meta-analyses show that media-violence viewing consistently is associated with higher levels of antisocial behavior, ranging from the trivial (imitative violence directed against toys) to the serious (criminal violence), with many consequential outcomes in between (acceptance of violence as a solution to problems, increased feelings of hostility, and the apparent delivery of painful stimulation to another person). Desensitization is another well-documented effect of viewing violence, which is observable in reduced arousal and emotional disturbance while witnessing violence, the reduced tendency to intervene in a fight, and less sympathy for the victims of violence. Although there is evidence that youth who are already violent are more likely to seek out violent entertainment, there is strong evidence that the relationship between violence viewing and antisocial behavior is bidirectional. There is growing evidence that media violence also engenders intense fear in children which often lasts days, months, and even years. The media's potential role in solutions to these problems is only beginning to be explored, in investigations examining the uses and effects of movie ratings, television ratings, and the V-chip, and the effects of media literacy programs and public education efforts. Future research should explore important individual differences in responses to media violence and effective ways to intervene in the negative effects.

Monitoring oil persistence on beaches : SCAT versus stratified random sampling designs

International Nuclear Information System (INIS)

Short, J.W.; Lindeberg, M.R.; Harris, P.M.; Maselko, J.M.; Pella, J.J.; Rice, S.D.

2003-01-01

In the event of a coastal oil spill, shoreline clean-up assessment teams (SCAT) commonly rely on visual inspection of the entire affected area to monitor the persistence of the oil on beaches. Occasionally, pits are excavated to evaluate the persistence of subsurface oil. This approach is practical for directing clean-up efforts directly following a spill. However, sampling of the 1989 Exxon Valdez oil spill in Prince William Sound 12 years later has shown that visual inspection combined with pit excavation does not offer estimates of contaminated beach area of stranded oil volumes. This information is needed to statistically evaluate the significance of change with time. Assumptions regarding the correlation of visually-evident surface oil and cryptic subsurface oil are usually not evaluated as part of the SCAT mandate. Stratified random sampling can avoid such problems and could produce precise estimates of oiled area and volume that allow for statistical assessment of major temporal trends and the extent of the impact. The 2001 sampling of the shoreline of Prince William Sound showed that 15 per cent of surface oil occurrences were associated with subsurface oil. This study demonstrates the usefulness of the stratified random sampling method and shows how sampling design parameters impact statistical outcome. Power analysis based on the study results, indicate that optimum power is derived when unnecessary stratification is avoided. It was emphasized that sampling effort should be balanced between choosing sufficient beaches for sampling and the intensity of sampling

Stratified flow model for convective condensation in an inclined tube

International Nuclear Information System (INIS)

Lips, Stéphane; Meyer, Josua P.

2012-01-01

Highlights: ► Convective condensation in an inclined tube is modelled. ► The heat transfer coefficient is the highest for about 20° below the horizontal. ► Capillary forces have a strong effect on the liquid–vapour interface shape. ► A good agreement between the model and the experimental results was observed. - Abstract: Experimental data are reported for condensation of R134a in an 8.38 mm inner diameter smooth tube in inclined orientations with a mass flux of 200 kg/m 2 s. Under these conditions, the flow is stratified and there is an optimum inclination angle, which leads to the highest heat transfer coefficient. There is a need for a model to better understand and predict the flow behaviour. In this paper, the state of the art of existing models of stratified two-phase flows in inclined tubes is presented, whereafter a new mechanistic model is proposed. The liquid–vapour distribution in the tube is determined by taking into account the gravitational and the capillary forces. The comparison between the experimental data and the model prediction showed a good agreement in terms of heat transfer coefficients and pressure drops. The effect of the interface curvature on the heat transfer coefficient has been quantified and has been found to be significant. The optimum inclination angle is due to a balance between an increase of the void fraction and an increase in the falling liquid film thickness when the tube is inclined downwards. The effect of the mass flux and the vapour quality on the optimum inclination angle has also been studied.

Social media visibility

DEFF Research Database (Denmark)

Uldam, Julie

2018-01-01

of activists remains under-researched. This article examines BP’s surveillance of activists who criticise the company’s corporate social responsibility (CSR) programme as ‘greenwashing’. In this way, it goes beyond corporations’ uses of big data and instead explores how they monitor and discuss strategies......As activists move from alternative media platforms to commercial social media platforms, they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in scholarly research and the media, corporate surveillance...... for responding to the activities of individual activists in social media. It shows that while social media afford an unprecedented level of visibility for activists, it comes with the risk of being monitored by corporations. Theoretically, it draws on conceptions of visibility in social sciences and media...

Internal Social Media

DEFF Research Database (Denmark)

Madsen, Vibeke Thøis

2018-01-01

Internal social media is a web-based communication arena that provides all organizational members with a communication opportunity. The media has emerged in organizations since 2004, and is increasingly seen as a way of giving employees a voice in organizations which can benefit the organization...... in terms of knowledge sharing, collaboration, and employee participation and engagement. The first wave of studies of internal social media was primarily from an information-systems perspective and focused more on its adoption, its affordances, and the outcome of its introduction. The second wave...... of studies was more concerned with studying the dynamics of communication on internal social media, in order to understand coworkers as strategic communicators and how communication on internal social media can constitute the organization. With a successful introduction of internal social media, coworkers...

Akun Resmi Media Sosial IMAJINASI FISIP USU Sebagai Media Pencarian Informasi (Studi Deskriptif Kuantitatif Penggunaan Akun Resmi Media Sosial IMAJINASI FISIP USU)

OpenAIRE

Nurdiningrum, Nurul

2017-01-01

130904171 Penelitian ini berjudul Akun Resmi Media Sosial IMAJINASI FISIP USU sebagai Media Pencarian Informasi (Studi Deskriptif Kuantitatif Penggunaan Akun Resmi Media Sosial IMAJINASI FISIP USU sebagai Media Pencarian Informasi pada Mahasiswa Ilmu Komunikasi).Tujuan penelitian adalah untuk mengetahui peranan akun resmi media sosial IMAJINASI FISIP USU sebagai media pencarian informasi pada mahasiswa Departemen Ilmu Komunikasi FISIP USU, untuk mengetahui jenis-jenis informasi yang dibagi...

'Frozen' media subsidies during a time of media change

DEFF Research Database (Denmark)

Nielsen, Rasmus Kleis

2014-01-01

documents and secondary sources, I show that media subsidies have largely remained frozen in their late-20th century form. The absence of major reform means that media subsidies are increasingly subject to policy drift, a process by which the operations and effectiveness of policies change not because......Media systems around the world have changed in significant ways in the early 21st century. In this article, I analyse how various forms of media subsidies have changed in response to these transformations in a sample of six different affluent democracies. On the basis of interviews, official......) a perceived shortage of desirable, cost-effective, and governable alternatives to existing policies....

Harnessing the landscape of microbial culture media to predict new organism–media pairings

Science.gov (United States)

Oberhardt, Matthew A.; Zarecki, Raphy; Gronow, Sabine; Lang, Elke; Klenk, Hans-Peter; Gophna, Uri; Ruppin, Eytan

2015-01-01

Culturing microorganisms is a critical step in understanding and utilizing microbial life. Here we map the landscape of existing culture media by extracting natural-language media recipes into a Known Media Database (KOMODO), which includes >18,000 strain–media combinations, >3300 media variants and compound concentrations (the entire collection of the Leibniz Institute DSMZ repository). Using KOMODO, we show that although media are usually tuned for individual strains using biologically common salts, trace metals and vitamins/cofactors are the most differentiating components between defined media of strains within a genus. We leverage KOMODO to predict new organism–media pairings using a transitivity property (74% growth in new in vitro experiments) and a phylogeny-based collaborative filtering tool (83% growth in new in vitro experiments and stronger growth on predicted well-scored versus poorly scored media). These resources are integrated into a web-based platform that predicts media given an organism's 16S rDNA sequence, facilitating future cultivation efforts. PMID:26460590

Design of a high-performance rotary stratified-charge research aircraft engine

Science.gov (United States)

Jones, C.; Mount, R. E.

1984-01-01

The power section for an advanced rotary stratified-charge general aviation engine has been designed under contract to NASA. The single-rotor research engine of 40 cubic-inches displacement (RCI-40), now being procured for test initiation this summer, is targeted for 320 T.O. horse-power in a two-rotor production engine. The research engine is designed for operating on jet-fuel, gasoline or diesel fuel and will be used to explore applicable advanced technologies and to optimize high output performance variables. Design of major components of the engine is described in this paper.

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

Science.gov (United States)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

Media Pembelajaran Global Warming

OpenAIRE

Tham, Fikri Jufri; Liliana, Liliana; Purba, Kristo Radion

2016-01-01

Computer based learning media is one of the media has an important role in learning. Learning media will be attractive when packaged through interactive media , such as interactive media created in paper manufacture " instructional media global warming" . The advantage gained is that it can increase knowledge, generally educate people to be more concerned about the environment , and also can be a means of entertainment. This application is focused to learn about global warming and packaged in...

Measuring News Media Literacy

Science.gov (United States)

Maksl, Adam; Ashley, Seth; Craft, Stephanie

2015-01-01

News media literacy refers to the knowledge and motivations needed to identify and engage with journalism. This study measured levels of news media literacy among 500 teenagers using a new scale measure based on Potter's model of media literacy and adapted to news media specifically. The adapted model posits that news media literate individuals…

Making Dutch pupils media conscious: preadolescents' self-assessment of possible media risks and the need for media education

NARCIS (Netherlands)

Küter-Luks, Theresa; Heuvelman, A.; Peters, O.

2011-01-01

Despite clear European and Dutch policies about media education, there is currently no media education curriculum in Dutch schools. A survey among preadolescents (n = 257) in six primary schools in the Netherlands included questions regarding media access, fears, risks, parental mediation of

Educational Potential of New Media

Directory of Open Access Journals (Sweden)

Maria Yu. Kazak

2017-11-01

Full Text Available Digitalization of the mass media, which has radically changed the information environment, creates new opportunities for self-education and upgrowth of the audience. The paper defines the communicative and cultural status of new media, characterizes the socio-cultural and technological aspects of their dynamics; substantiates the necessity of elaborating mechanisms for systematization of heterogeneous information flows and elaborating criteria for their evaluation in the era of globalization of the media sphere, what implies a qualitatively different level of media competence of the audience, provided with such factors as media education, media coverage, media criticism. The definition of concepts "media competence", "media enlightenment", "media education", "media criticism" is given and their functional areas are delineated. Social networks are considered as an important tool for media enlightenment which provides significant opportunities for promoting cultural achievements in the new media environment.

Investigation and mitigation of condensation induced water hammer by stratified flow experiments

Science.gov (United States)

Kadakia, Hiral J.

This research primarily focuses on the possibility of using stratified flow in preventing an occurrence of condensation induced water hammer (CIWH) in horizontal pipe involving steam and subcooled water. A two-phase flow loop simulating the passive safety systems of an advanced light water reactor was constructed and a series of stratified flow experiments were carried out involving a system of subcooled water, saturated water, and steam. Special instruments were designed to measure steam flow rate and subcooled liquid velocity. These experiments showed that when flow field conditions meet certain criteria CIWH does occur. Flow conditions used in experiments were typically observed in passive safety systems of an advanced light water cooled reactor. This research summarizes a) literature research and other experimental data that signify an occurrence of CIWH, b) experiments in an effort to show an occurrence of CIWH and the ability to prevent CIWH, c) qualitative and quantitative results to underline the mechanism of CIWH, d) experiments that show CIWH can be prevented under certain conditions, and e) guidelines for the safe operating conditions. Based on initial experiment results it was observed that Bernoulli's effect can play an important role in wave formation and instability. A separate effect table top experiment was constructed with plexi-glass. A series of entrance effect tests and stratified experiments were carried out with different fluids to study wave formation and wave bridging. Special test series experiments were carried out to investigate the presence of a saturated layer. The effect of subcooled water and steam flow on wedge length and depth were recorded. These experiments helped create a model which calculates wedge and depth of wedge for a given condition of steam and subcooled water. A very good comparison between the experiment results and the model was obtained. These experiments also showed that the presence of saturated layer can mitigate

Solution of Media Risk and Social Responsibility Governance of Social Media

Directory of Open Access Journals (Sweden)

Zhang Yuan

2017-01-01

Full Text Available The rapid development of media technology makes the modern society become a “social media” or even “over social media”, the rise of social media makes it beyond the tool attribute, and become an important force in the reconstruction of contemporary society, the risk of concomitant. The anomie and breach of Social media regularly staged, weakened its positive social function, forcing us to think about the social responsibility of social media,which are reflections on the lack of responsibility, but also positive response of resolving the media risk and ask for moral strength.

Adolescents and media literacy.

Science.gov (United States)

McCannon, Robert

2005-06-01

In the face of media industry consolidation, fewer people control media content which makes it harder for parents and citizens to know the research about media-related issues, such as video game violence, nutrition, and sexual risk-taking. Media literacy offers a popular and potentially successful way to counter the misinformation that is spread by Big Media public relations.

Fra massemedier til mediesystem - om kodediskussionen i systemteoretisk medieforskning [From mass media to media system - code discussions in systems theoretical media research

Directory of Open Access Journals (Sweden)

Mikkel Fugl Eskjær

2010-11-01

Full Text Available Systems theoretical media research raises the question whether the mass media constitute a unified institution, or whether the media, due to their internal differences, should be considered individually and independent of each other. By inscribing the media in a general social theory, systems theory conceptualises the media as an autonomous functional system. This intention is most clearly illustrated by the efforts to identify a shared code for the entire media system. Based on the media theory of Niklas Luhmann, this paper offers a critical presentation of the code discussion within systems theoretical media research. The first part of the paper briefly introduces the systems theoretical notion of a code as well as Luhmann’s definition of the media system as organised and regulated by the code of information. The second part presents a number of alternative suggestions and definitions of the media system’s code, which both indicate the scope of systems theoretical media research, but also point to some of the limitations in the systems theoretical approach. In the last part, the paper takes a critical look at the systems theoretical code discussion by arguing that a too narrow focus on code definitions is blocking a more productive investigation of the conditions, evolution, and autonomy of the media system.

Media multitasking and implicit learning.

Science.gov (United States)

Edwards, Kathleen S; Shin, Myoungju

2017-07-01

Media multitasking refers to the simultaneous use of different forms of media. Previous research comparing heavy media multitaskers and light media multitaskers suggests that heavy media multitaskers have a broader scope of attention. The present study explored whether these differences in attentional scope would lead to a greater degree of implicit learning for heavy media multitaskers. The study also examined whether media multitasking behaviour is associated with differences in visual working memory, and whether visual working memory differentially affects the ability to process contextual information. In addition to comparing extreme groups (heavy and light media multitaskers) the study included analysis of people who media multitask in moderation (intermediate media multitaskers). Ninety-four participants were divided into groups based on responses to the media use questionnaire, and completed the contextual cueing and n-back tasks. Results indicated that the speed at which implicit learning occurred was slower in heavy media multitaskers relative to both light and intermediate media multitaskers. There was no relationship between working memory performance and media multitasking group, and no relationship between working memory and implicit learning. There was also no evidence for superior performance of intermediate media multitaskers. A deficit in implicit learning observed in heavy media multitaskers is consistent with previous literature, which suggests that heavy media multitaskers perform more poorly than light media multitaskers in attentional tasks due to their wider attentional scope.

Media Flow

DEFF Research Database (Denmark)

Kabel, Lars

2016-01-01

News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....

If I tweet will you cite? The effect of social media exposure of articles on downloads and citations.

Science.gov (United States)

Tonia, Thomy; Van Oyen, Herman; Berger, Anke; Schindler, Christian; Künzli, Nino

2016-05-01

We sought to investigate whether exposing scientific papers to social media (SM) has an effect on article downloads and citations. We randomized all International Journal of Public Health (IJPH) original articles published between December 2012 and December 2014 to SM exposure (blog post, Twitter and Facebook) or no exposure at three different time points after first online publication. 130 papers (SM exposure = 65, control = 65) were randomized. The number of downloads did not differ significantly between groups (p = 0.60) nor did the number of citations (p = 0.88). Adjusting for length of observation and paper's geographical origin did not change these results. There was no difference in the number of downloads and citations between the SM exposure and control group when we stratified for open access status. The number of downloads and number of citations were significantly correlated in both groups. SM exposure did not have a significant effect on traditional impact metrics, such as downloads and citations. However, other metrics may measure the added value that social media might offer to a scientific journal, such as wider dissemination.

The development of children's language and ethical media competences and media skills

OpenAIRE

Valli, Raine; Hautaviita, Janika; Meriläinen, Merja

2015-01-01

The children's developing media competences and media skills are evaluated in this article on the basis of the evaluation indicator developed by Hautaviita (2012). The indicator has been developed for measuring the 6–9-year-old children's (the preschoolers and the pupils in grades 1-2) media competences. In it, the children's developing media skills are divided into practical, social, language and ethical media competences, of which this article concentrates on the last two, language and ethi...

Applying East Asian Media Diplomacy Models to African Media: A ...

African Journals Online (AJOL)

The last two decades have seen the extensive expansion of South African and Nigerian media on the African continent. However, while the link between media and diplomacy, and the role of media in visualising the state for foreign audiences have received a lot of scholarly attention internationally, relatively little work has ...

Need for Orientation, Media Uses and Gratifications, and Media Effects.

Science.gov (United States)

Weaver, David

In order to study the influence of need for orientation and media gratifications on media use and media effects in political communication, two previous surveys were studied to compare the causal modeling approach and the contingent conditions approach. In the first study, 339 personal interviews were conducted with registered voters during a…

Media Pluralism and Diversity

DEFF Research Database (Denmark)

In the western world, a diverse and pluralistic media landscape is deemed essential for democracy. But how universal is media pluralism as a concept underpinning media policies? To what extent do normative approaches, regulatory dimensions and monitoring systems differ throughout the world......? Adopting a truly global, theoretical and multidisciplinary perspective, Media Pluralism and Diversity advances our understanding of media pluralism across the globe. It compares metrics developed in different parts of the world to assess levels of, or threats to, media pluralism. It identifies common...

An experimental simulation study of debris quenching in a radially stratified porous bed

International Nuclear Information System (INIS)

Sehgal, B.R.; Nayak, A.K.; Stepanyan, A.

2004-01-01

During a severe accident condition in a nuclear power plant, the core melt can fail the reactor vessel and relocate into the containment basement. In some accident management schemes, the vessel cavity is flooded with water. For these a particulate debris bed is likely to form on the cavity floor due to melt break-up in water. . In this situation, the coolability of debris bed on the containment floor is a crucial issue. This is because the debris bed still generates the decay heat and if it is uncoolable, it can eventually remelt and react with concrete basement generating a lot of noncondensable gases and pressurising the containment. Hence, it is important to cool the debris bed as an accident management programme. The main parameters affecting the coolability of the debris bed are its porosity which is a function of the size and shape of the particles which constitute the debris bed, the operating condition such as water flooding from the top or bottom of debris bed, water temperature and non-condensable gas generated during bed-concrete interactions. It is found from previous studies that the debris bed has a non-uniform particle distribution or a porosity stratification. This can happen both in radial and axial plane. For example, the bed can have a lower porosity at the centre and higher porosity at the periphery. It is of interest to investigate the quenching phenomena in such configurations so as to find an effective means of quenching the heat generating bed. While most of the previous investigations mainly concentrate on quenching of a homogenous or axially stratified particulate bed with volumetric heat generation, there are almost no studies on the above phenomena in a radially stratified porous bed. So the objective of this paper is to investigate the quenching phenomena in a radially stratified bed. To simulate the phenomena, we conducted experiments in an experimental facility named as POMECO (POrous MEdia COolability). The facility has a square

The Potential of an Alliance of Media Literacy Education and Media Criticism in Russia

Science.gov (United States)

Levitskaya, Anastasia

2015-01-01

Media criticism and media literacy education have much in common. For example, media literacy education and media criticism attaches great importance to the development of analytical thinking audience. Indeed, one of the most important tasks of media literacy education is precisely to teach the audience not only to analyze media texts of any kinds…

Mass Media: The Invisible Environment.

Science.gov (United States)

Glessing, Robert J.; White, William P.

This anthology for students of media consists of essays and articles grouped under four topics: media forms, media content, media environments, and "the last word." Media forms deals with the nature of these kinds of media: electronic, print, film, music, and comics, graffiti, and clothing. Media content contains articles on the news, advertising,…

Deep silicon maxima in the stratified oligotrophic Mediterranean Sea

Directory of Open Access Journals (Sweden)

Y. Crombet

2011-02-01

Full Text Available The silicon biogeochemical cycle has been studied in the Mediterranean Sea during late summer/early autumn 1999 and summer 2008. The distribution of nutrients, particulate carbon and silicon, fucoxanthin (Fuco, and total chlorophyll-a (TChl-a were investigated along an eastward gradient of oligotrophy during two cruises (PROSOPE and BOUM encompassing the entire Mediterranean Sea during the stratified period. At both seasons, surface waters were depleted in nutrients and the nutriclines gradually deepened towards the East, the phosphacline being the deepest in the easternmost Levantine basin. Following the nutriclines, parallel deep maxima of biogenic silica (DSM, fucoxanthin (DFM and TChl-a (DCM were evidenced during both seasons with maximal concentrations of 0.45 μmol L⁻¹ for BSi, 0.26 μg L⁻¹ for Fuco, and 1.70 μg L⁻¹ for TChl-a, all measured during summer. Contrary to the DCM which was a persistent feature in the Mediterranean Sea, the DSM and DFMs were observed in discrete areas of the Alboran Sea, the Algero-Provencal basin, the Ionian sea and the Levantine basin, indicating that diatoms were able to grow at depth and dominate the DCM under specific conditions. Diatom assemblages were dominated by Chaetoceros spp., Leptocylindrus spp., Pseudonitzschia spp. and the association between large centric diatoms (Hemiaulus hauckii and Rhizosolenia styliformis and the cyanobacterium Richelia intracellularis was observed at nearly all sites. The diatom's ability to grow at depth is commonly observed in other oligotrophic regions and could play a major role in ecosystem productivity and carbon export to depth. Contrary to the common view that Si and siliceous phytoplankton are not major components of the Mediterranean biogeochemistry, we suggest here that diatoms, by persisting at depth during the stratified period, could contribute to a

Procedural Media Representation

OpenAIRE

Henrysson, Anders

2002-01-01

We present a concept for using procedural techniques to represent media. Procedural methods allow us to represent digital media (2D images, 3D environments etc.) with very little information and to render it photo realistically. Since not all kind of content can be created procedurally, traditional media representations (bitmaps, polygons etc.) must be used as well. We have adopted an object-based media representation where an object can be represented either with a procedure or with its trad...

The Media Mixer

DEFF Research Database (Denmark)

Vestergaard, Vitus; Mortensen, Christian Hviid

In recent years many museums have experimented with different approaches to involving users through digital media. We explore how remixing and content sharing can be used as a means for user participation. Remix culture is seen as a culture that allows and encourages the production of derivative...... works; works that are based on already existing works. This cultural practice thrives throughout the Internet, most notably on web2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here...... the museum users can produce, deconstruct, reconstruct and finally publish and share digital media content. The media content is created by the user in the museums physical environment, but it can be mixed with material from local or global archives. In that way the gap between the analogue and the digital...

PENGEMBANGAN MEDIA PEMBELAJARAN FILM ANIMASI SEBAGAI MEDIA PEMBELAJARAN KONSEP FOTOSINTESIS

Directory of Open Access Journals (Sweden)

Umrotul Hasanah

2015-11-01

Full Text Available The research aims to develop animation film as a learning media in photosynthesis concept learning and to know the results of the assessment of the learning media expert test the concept of photosynthesis animated films. This research is Research and Development (R&D. The research used questionnaire Aspects of assessment in terms of the media covering aspects of technical quality, narration, and music/sound effects. Aspects of the assessment of the suitability of the material terms covering the material aspects of the curriculum, the clarity of the material, the order of the material, communicative, suitability of the material with the purpose of learning, material relationship with the students’ critical thinking skill, and material relationship with motivation. Media expert test against “Cahaya dan Fotosintesis” animated film made by media experts with a percentage of 80,6% with the as good category, and 92,5% are material expert excellent category. Based on the “Cahaya dan Fotosintesis” animated film expert test to students can be tasted on a limited basis, after the media deficiencies corrected.

Media Outlook 2016: A Survey of UK Media Trends and Firm Capabilities

OpenAIRE

Oliver, John James

2016-01-01

The aim of this survey is to understand the changing nature of the UK media environment, emerging trends and the management practices of media executives. This is the fourth year that the survey has run, and already we are seeing immense changes in the way media firms are adapting to a changing competitive landscape. This year, the focus of the survey has been on assessing media firm capabilities and the ability to adapt media strategy, business models and capabilities to new industry dynamic...

75 FR 77670 - SuperMedia, LLC, Formerly Known as Idearc Media, LLC, a Subsidiary of SuperMedia Information...

Science.gov (United States)

2010-12-13

... Known as Idearc Media, LLC, a Subsidiary of SuperMedia Information Services, LLC Publishing Group, Troy... Subsidiary of SuperMedia Information Services, LLC, Troy, New York, to apply for Trade Adjustment Assistance..., Publishing Group, Troy, New York, who became totally or partially separated from employment on or after...

Advocates' Experiences With Media and the Impact of Media on Human Trafficking Advocacy.

Science.gov (United States)

Houston-Kolnik, Jaclyn D; Soibatian, Christina; Shattell, Mona M

2017-02-01

The present qualitative study explores advocates' opinions of misinformation about human trafficking in the media and describes advocates' strategies to counter the misinformation presented by the media. Thus, 15 advocates who work against human trafficking in Chicago-based nonprofit organizations participated in semistructured interviews about their opinions and strategies. Data were analyzed using thematic content analysis. The present study identifies specific misperceptions of human trafficking in the media, highlights advocates' opinions of this misinformation, and discusses advocates' strategies to counteract inaccurate media, adding support to the role of media advocacy. Advocates note how media images shape and perpetuate stereotypes of trafficking through glamorizing sex work and sensationalizing stories that are most often international depictions of trafficking. Advocates report media generally shares only a piece of the story, simplifying the stories of survivors and the issue of human trafficking. Advocates critique media perpetuating these misperceptions for how they may contribute to policies and programs which fail to address structural factors that create vulnerabilities to be trafficked and the multisystem needs of survivors. However, advocates also note misperceptions can be counteracted by producing sensitive, informed media through social platforms. Advocates share their strategies counteracting misinformation through engaging in informative conversations, utilizing social media to educate, and promoting media messages of survivor agency. Research, clinical, and policy implications are also discussed. The present study emphasizes the importance of decision makers and service providers being critical consumers of media and to assess how media portrayals may (or may not) inform their understanding and response to the issue.

Effects of unstratified and centre-stratified randomization in multi-centre clinical trials.

Science.gov (United States)

Anisimov, Vladimir V

2011-01-01

This paper deals with the analysis of randomization effects in multi-centre clinical trials. The two randomization schemes most often used in clinical trials are considered: unstratified and centre-stratified block-permuted randomization. The prediction of the number of patients randomized to different treatment arms in different regions during the recruitment period accounting for the stochastic nature of the recruitment and effects of multiple centres is investigated. A new analytic approach using a Poisson-gamma patient recruitment model (patients arrive at different centres according to Poisson processes with rates sampled from a gamma distributed population) and its further extensions is proposed. Closed-form expressions for corresponding distributions of the predicted number of the patients randomized in different regions are derived. In the case of two treatments, the properties of the total imbalance in the number of patients on treatment arms caused by using centre-stratified randomization are investigated and for a large number of centres a normal approximation of imbalance is proved. The impact of imbalance on the power of the study is considered. It is shown that the loss of statistical power is practically negligible and can be compensated by a minor increase in sample size. The influence of patient dropout is also investigated. The impact of randomization on predicted drug supply overage is discussed. Copyright © 2010 John Wiley & Sons, Ltd.

From Near-Neutral to Strongly Stratified: Adequately Modelling the Clear-Sky Nocturnal Boundary Layer at Cabauw.

Science.gov (United States)

Baas, P; van de Wiel, B J H; van der Linden, S J A; Bosveld, F C

2018-01-01

The performance of an atmospheric single-column model (SCM) is studied systematically for stably-stratified conditions. To this end, 11 years (2005-2015) of daily SCM simulations were compared to observations from the Cabauw observatory, The Netherlands. Each individual clear-sky night was classified in terms of the ambient geostrophic wind speed with a [Formula: see text] bin-width. Nights with overcast conditions were filtered out by selecting only those nights with an average net radiation of less than [Formula: see text]. A similar procedure was applied to the observational dataset. A comparison of observed and modelled ensemble-averaged profiles of wind speed and potential temperature and time series of turbulent fluxes showed that the model represents the dynamics of the nocturnal boundary layer (NBL) at Cabauw very well for a broad range of mechanical forcing conditions. No obvious difference in model performance was found between near-neutral and strongly-stratified conditions. Furthermore, observed NBL regime transitions are represented in a natural way. The reference model version performs much better than a model version that applies excessive vertical mixing as is done in several (global) operational models. Model sensitivity runs showed that for weak-wind conditions the inversion strength depends much more on details of the land-atmosphere coupling than on the turbulent mixing. The presented results indicate that in principle the physical parametrizations of large-scale atmospheric models are sufficiently equipped for modelling stably-stratified conditions for a wide range of forcing conditions.

From Near-Neutral to Strongly Stratified: Adequately Modelling the Clear-Sky Nocturnal Boundary Layer at Cabauw

Science.gov (United States)

Baas, P.; van de Wiel, B. J. H.; van der Linden, S. J. A.; Bosveld, F. C.

2018-02-01

The performance of an atmospheric single-column model (SCM) is studied systematically for stably-stratified conditions. To this end, 11 years (2005-2015) of daily SCM simulations were compared to observations from the Cabauw observatory, The Netherlands. Each individual clear-sky night was classified in terms of the ambient geostrophic wind speed with a 1 m s^{-1} bin-width. Nights with overcast conditions were filtered out by selecting only those nights with an average net radiation of less than - 30 W m^{-2}. A similar procedure was applied to the observational dataset. A comparison of observed and modelled ensemble-averaged profiles of wind speed and potential temperature and time series of turbulent fluxes showed that the model represents the dynamics of the nocturnal boundary layer (NBL) at Cabauw very well for a broad range of mechanical forcing conditions. No obvious difference in model performance was found between near-neutral and strongly-stratified conditions. Furthermore, observed NBL regime transitions are represented in a natural way. The reference model version performs much better than a model version that applies excessive vertical mixing as is done in several (global) operational models. Model sensitivity runs showed that for weak-wind conditions the inversion strength depends much more on details of the land-atmosphere coupling than on the turbulent mixing. The presented results indicate that in principle the physical parametrizations of large-scale atmospheric models are sufficiently equipped for modelling stably-stratified conditions for a wide range of forcing conditions.

Open Media Science

DEFF Research Database (Denmark)

Martiny, Kristian Møller Moltke; Pedersen, David Budtz; Hansted, Alfred Birkegaard

2016-01-01

and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...

DEVELOPMENT OF STUDENTS’ MEDIA LITERACY IN THE PROCESS OF CREATING SCHOOL MEDIA

Directory of Open Access Journals (Sweden)

Julia Rybina

2017-04-01

Full Text Available Nowadays, a rapid development of information and communication technologies enables combine a number of formats for presenting information into one communication unit. That is why the media (Internet especially is not just tools for young generation for learning the modern world. Children enjoy in dealing with modern technologies. However not everyone has sufficient skills to objectively assess the true meaning of the information received. That is why children are more inclined for their mind to be manipulated and they are more inclined for blind imitating of attractive images. Owning to the above, the most priority-driven of modern education is the usage of information and communication technologies and media education for forming the skills of students' orientation in the information field and for forming the development of media immunity of the personality which makes the personality able to resist to the aggressive media space. Teachers face the challenge of introducing media education in middle and high schools. To implement the media education at the municipal institution regional specialized residential school “Giftedness” the pedagogical experiment was carried out there. The basis of the experiment is the generalized model of media literacy development for students that was used during for making and functioning the school newspaper «D.A.R-media». Theoretical aspects of the implementation of media education in the teaching and educational process of a specialized educational institution are considered in this study. A model for the development of the media literacy of students in the process of creating a school printed publication is proposed. Some results of research on the level of media literacy of students are highlighted and prospects for work on introducing media education of teachers and teachers are outlined.

Turbulent transport of passive scalar behind line sources in an unstably stratified open channel flow

Energy Technology Data Exchange (ETDEWEB)

Liu, Chun-Ho [The Hong Kong Polytechnic University, Kowloon (Hong Kong). Department of Building and Real Estate; Leung, Dennis Y.C. [The University of Hong Kong (Hong Kong). Department of Mechanical Engineering

2006-11-15

This study employs a direct numerical simulation (DNS) technique to study the flow, turbulence structure, and passive scalar plume transport behind line sources in an unstably stratified open channel flow. The scalar transport behaviors for five emission heights (z{sub s}=0, 0.25H, 0.5H, 0.75H, and H, where H is the channel height) at a Reynolds number of 3000, a Prandtl number and a Schmidt number of 0.72, and a Richardson number of -0.2 are investigated. The vertically meandering mean plume heights and dispersion coefficients calculated by the current DNS model agree well with laboratory results and field measurements in literature. It is found that the plume meandering is due to the movement of the positive and negative vertical turbulent scalar fluxes above and below the mean plume heights, respectively. These findings help explaining the plume meandering mechanism in the unstably stratified atmospheric boundary layer. (author)

Internal combustion engine using premixed combustion of stratified charges

Science.gov (United States)

Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

2003-12-30

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Making Dutch Pupils Media Conscious: Preadolescents' Self-Assessment of Possible Media Risks and the Need for Media Education

Science.gov (United States)

Kuter-Luks, Theresa; Heuvelman, Ard; Peters, Oscar

2011-01-01

Despite clear European and Dutch policies about media education, there is currently no media education curriculum in Dutch schools. A survey among preadolescents (n = 257) in six primary schools in the Netherlands included questions regarding media access, fears, risks, parental mediation of television and the internet, and the need for media…

Asian Media Productions

DEFF Research Database (Denmark)

This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research, ......, they have written a book on the social practices and cultural attitudes of people producing, reading, watching and listening to different kinds of media in Japan, China, Taiwan, Indonesia, Vietnam, Singapore and India....

The social media revolution.

Science.gov (United States)

Dubose, Cheryl

2011-01-01

The growing popularity and use of social media tools such as Facebook, YouTube, Twitter, blogging, and wikis have led to a social media revolution. Given this widespread influence, it is important for educators, administrators, and technologists to understand the risks of using social media in the classroom and workplace. To investigate popular social media sites and their effect on radiologic technology education and business practices. A comprehensive search of literature was performed to examine social media and its applications in education, health care, and business. Social media use is on the rise, affecting all aspects of mainstream society. Leaders in the radiologic sciences should be familiar with social media and cognizant of its risks. Future studies regarding social media use in the radiologic sciences are necessary to determine its effect on the radiologic science community. ©2011 by the American Society of Radiologic Technologists.

MODERN MEDIA EDUCATION MODELS

Directory of Open Access Journals (Sweden)

Alexander Fedorov

2011-03-01

Full Text Available The author supposed that media education models can be divided into the following groups:- educational-information models (the study of the theory, history, language of media culture, etc., based on the cultural, aesthetic, semiotic, socio-cultural theories of media education;- educational-ethical models (the study of moral, religions, philosophical problems relying on the ethic, religious, ideological, ecological, protectionist theories of media education;- pragmatic models (practical media technology training, based on the uses and gratifications and ‘practical’ theories of media education;- aesthetical models (aimed above all at the development of the artistic taste and enriching the skills of analysis of the best media culture examples. Relies on the aesthetical (art and cultural studies theory; - socio-cultural models (socio-cultural development of a creative personality as to the perception, imagination, visual memory, interpretation analysis, autonomic critical thinking, relying on the cultural studies, semiotic, ethic models of media education.

Pengguna Media Interaktif Sebagai Kenyataan Maya: Studi Resepsi Khalayak Suarasurabaya.net Sebagai Media Interaktif

Directory of Open Access Journals (Sweden)

Ido Prijana Hadi

2011-07-01

Full Text Available My aim in writing this paper is to describe that in this fast-changing world, media in Indonesia has undergone a rapid transformation. Digital technology continues to reshape the mass media landscape using internet technology. Internet brings a technical communication revolution, a fundamental change takes place in the structure of connections, artificial memories and the reproduction of their content. Internet technology has made communication much easier and less expensive. It has attracted many people and has penetrated into people’s daily lives. The mass media also have accepted the internet. Almost all forms of traditional media (old media in local media, such as radio, television, and newspaper have extended their work into this new field. The internet and the World Wide Web have both significantly influenced modern journalism. In online media allows readers to enjoy browsing their product and service of contents, such as news feed, podcasts, desktop alert, news on mobile phones, PDA and others mobile devices. Online media offer not only text but also digital images , audio file, moving images (video, internet radio and internet t v. The interactive features of the internet seemingly imply that online media have more advantages than traditional media forms (old media. So, the internet have dramatically evolved become new media with characteristic multimedia, hypertext, interactivity, archives , and virtuality. The most important structural new media characteristic is the integration of telecommunications, data communications and mass communication in a single medium – it is the convergence. It should be pointed out that the trend toward digital is affecting the various media and brings the local media in East Java to become a global media, where breaking news from Surabaya or anywhere in East Java is transmitted to around the world in a matter of minutes . The research was carried out to find out how user reception on convergence media

Selection and Evaluation of Media for Behavioral Health Interventions Employing Critical Media Analysis.

Science.gov (United States)

Wilson, Patrick A; Cherenack, Emily M; Jadwin-Cakmak, Laura; Harper, Gary W

2018-01-01

Although a growing number of psychosocial health promotion interventions use the critical analysis of media to facilitate behavior change, no specific guidelines exist to assist researchers and practitioners in the selection and evaluation of culturally relevant media stimuli for intervention development. Mobilizing Our Voices for Empowerment is a critical consciousness-based health enhancement intervention for HIV-positive Black young gay/bisexual men that employs the critical analysis of popular media. In the process of developing and testing this intervention, feedback on media stimuli was collected from youth advisory board members (n = 8), focus group participants (n = 19), intervention participants (n = 40), and intervention facilitators (n = 6). A thematic analysis of qualitative data resulted in the identification of four key attributes of media stimuli and participants' responses to media stimuli that are important to consider when selecting and evaluating media stimuli for use in behavioral health interventions employing the critical analysis of media: comprehension, relevance, emotionality, and action. These four attributes are defined and presented as a framework for evaluating media, and adaptable tools are provided based on this framework to guide researchers and practitioners in the selection and evaluation of media for similar interventions.

Clinical research in small genomically stratified patient populations.

Science.gov (United States)

Martin-Liberal, J; Rodon, J

2017-07-01

The paradigm of early drug development in cancer is shifting from 'histology-oriented' to 'molecularly oriented' clinical trials. This change can be attributed to the vast amount of tumour biology knowledge generated by large international research initiatives such as The Cancer Genome Atlas (TCGA) and the use of next generation sequencing (NGS) techniques developed in recent years. However, targeting infrequent molecular alterations entails a series of special challenges. The optimal molecular profiling method, the lack of standardised biological thresholds, inter- and intra-tumor heterogeneity, availability of enough tumour material, correct clinical trials design, attrition rate, logistics or costs are only some of the issues that need to be taken into consideration in clinical research in small genomically stratified patient populations. This article examines the most relevant challenges inherent to clinical research in these populations. Moreover, perspectives from the Academia point of view are reviewed as well as initiatives to be taken in forthcoming years. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advanced stratified charge rotary aircraft engine design study

Science.gov (United States)

Badgley, P.; Berkowitz, M.; Jones, C.; Myers, D.; Norwood, E.; Pratt, W. B.; Ellis, D. R.; Huggins, G.; Mueller, A.; Hembrey, J. H.

1982-01-01

A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage.

Cross-media advertising: brand promotion in an age of media convergence

NARCIS (Netherlands)

Voorveld, H.; Smit, E.; Neijens, P.; Diehl, S.; Karmasin, M.

2013-01-01

Cross-media advertising, in which more than one medium platform is used to communicate related brand content, has become widespread. Several reasons for cross-media strategies can be distinguished: target group extension, complementary effects, repetition, and synergy. Media synergy—the added value

The impacts of post-media networks on the traditional media

Directory of Open Access Journals (Sweden)

Dr. Francisco Campos Freire

2008-01-01

Full Text Available The fast and successful penetration in society of the so-called social networks in the past two or three years has alarmed the traditional media. The new phenomenon reaches a wider audience, enhances advertising, achieves customization, and breaches some of the barriers of traditional media. The new communication channel is used already by millions of Internet users as their main source of information and entertainment. This research paper analyses the structure of eleven global social networks, which feature contents in Spanish and other languages, in relation to the electronic version (e-version of the main Spanish newspapers. The aim is to prove if the so-called social networks are a new type of media, a new platform for social relationships and post-media contents, which look more like the audiovisual media than the traditional newspapers.

Comprehension of digital media

International Nuclear Information System (INIS)

Kim, Ju Hwan

2008-11-01

This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

Comprehension of digital media

Energy Technology Data Exchange (ETDEWEB)

Kim, Ju Hwan

2008-11-15

This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

Post Media Literacy: Menyaksikan Kuasa Media Bersama Michel Foucault

OpenAIRE

Iswandi Syahputra

2017-01-01

This article would like to present Michel Foucault’s idea concerning Knowledge and Power in media industry. As a contemporary intellectual, Foucault’s thought has a unique style of postmodernism. His thought had gone beyond traditional critical theory whose trying to disclose the relation of power and economic behind the ideology of media. Foucault’s thought had given new perspective in understanding how the media produce truth under tightly control process into something that seems normal. ...

A 3D spectral anelastic hydrodynamic code for shearing, stratified flows

Science.gov (United States)

Barranco, Joseph A.; Marcus, Philip S.

2006-11-01

We have developed a three-dimensional (3D) spectral hydrodynamic code to study vortex dynamics in rotating, shearing, stratified systems (e.g., the atmosphere of gas giant planets, protoplanetary disks around newly forming protostars). The time-independent background state is stably stratified in the vertical direction and has a unidirectional linear shear flow aligned with one horizontal axis. Superposed on this background state is an unsteady, subsonic flow that is evolved with the Euler equations subject to the anelastic approximation to filter acoustic phenomena. A Fourier Fourier basis in a set of quasi-Lagrangian coordinates that advect with the background shear is used for spectral expansions in the two horizontal directions. For the vertical direction, two different sets of basis functions have been implemented: (1) Chebyshev polynomials on a truncated, finite domain, and (2) rational Chebyshev functions on an infinite domain. Use of this latter set is equivalent to transforming the infinite domain to a finite one with a cotangent mapping, and using cosine and sine expansions in the mapped coordinate. The nonlinear advection terms are time-integrated explicitly, the pressure/enthalpy terms are integrated semi-implicitly, and the Coriolis force and buoyancy terms are treated semi-analytically. We show that internal gravity waves can be damped by adding new terms to the Euler equations. The code exhibits excellent parallel performance with the message passing interface (MPI). As a demonstration of the code, we simulate the merger of two 3D vortices in the midplane of a protoplanetary disk.

Turbulent entrainment across turbulent-nonturbulent interfaces in stably stratified mixing layers

Science.gov (United States)

Watanabe, T.; Riley, J. J.; Nagata, K.

2017-10-01

The entrainment process in stably stratified mixing layers is studied in relation to the turbulent-nonturbulent interface (TNTI) using direct numerical simulations. The statistics are calculated with the interface coordinate in an Eulerian frame as well as with the Lagrangian fluid particles entrained from the nonturbulent to the turbulent regions. The characteristics of entrainment change as the buoyancy Reynolds number Reb decreases and the flow begins to layer. The baroclinic torque delays the enstrophy growth of the entrained fluids at small Reb, while this effect is less efficient for large Reb. The entrained particle movement within the TNTI layer is dominated by the small dissipative scales, and the rapid decay of the kinetic energy dissipation rate due to buoyancy causes the entrained particle movement relative to the interface location to become slower. Although the Eulerian statistics confirm that there exists turbulent fluid with strong vorticity or with large buoyancy frequency near the TNTI, the entrained fluid particles circumvent these regions by passing through the TNTI in strain-dominant regions or in regions with small buoyancy frequency. The multiparticle statistics show that once the nonturbulent fluid volumes are entrained, they are deformed into flattened shapes in the vertical direction and diffuse in the horizontal direction. When Reb is large enough for small-scale turbulence to exist, the entrained fluid is able to penetrate into the turbulent core region. Once the flow begins to layer with decreasing Reb, however, the entrained fluid volume remains near the outer edge of the turbulent region and forms a stably stratified layer without vertical overturning.

Turkish Press in Social Media

OpenAIRE

AYTEN, Adem

2013-01-01

Social media, is one of the most researched facts today by the commications fellows. To get in use by Web 2.0 social media becomes common due to the rise of using mobile technologies. Instead of competing with traditional media and being an alternative media, social media is a new media that traditional media can transfer its content to it and can benefit its advantages. Indeed,the traditional media carried its content to the websites to access of their readers/listeners/watchers to compete ...

Children's Media Policy

Science.gov (United States)

Jordan, Amy B.

2008-01-01

Amy Jordan addresses the need to balance the media industry's potentially important contributions to the healthy development of America's children against the consequences of excessive and age-inappropriate media exposure. Much of the philosophical tension regarding how much say the government should have about media content and delivery stems…

Youth media lifestyles

NARCIS (Netherlands)

van Kruistum, Claudia; Leseman, Paul Pm; de Haan, Mariëtte

2014-01-01

In this article, the concept of "media lifestyles" is adopted in order to develop a comprehensive approach toward youth engagement in communication media. We explore how 503 Dutch eighth grade students with full access to new technology combine a broad range of media by focusing on their engagement

The parental media mediation context of young children’s media use

NARCIS (Netherlands)

Piotrowski, J.T.; Barr, R.; Linebarger, D.N.

2017-01-01

Researchers widely agree that how children spend their time is an important predictor of the development of their skills, relationships, attitudes, and behavior patterns. And while media estimates indicate that media play a considerable presence in the daily life of most youngsters today, media use

Understanding Social Media Logic

OpenAIRE

José van Dijck; Thomas Poell

2013-01-01

Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media log...

MediaTracker system

Energy Technology Data Exchange (ETDEWEB)

Sandoval, D. M. (Dana M.); Strittmatter, R. B. (Richard B.); Abeyta, J. D. (Joline D.); Brown, J. (John); Marks, T. (Thomas), Jr.; Martinez, B. J. (Benny J.); Jones, D. B. (Dana Benelli); Hsue, W.

2004-01-01

The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can

MediaTracker system

International Nuclear Information System (INIS)

Sandoval, D.M.; Strittmatter, R.B.; Abeyta, J.D.; Brown, J.; Marks, T. Jr.; Martinez, B.J.; Jones, D.B.; Hsue, W.

2004-01-01

The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can accommodate

Solution of Media Risk and Social Responsibility Governance of Social Media

OpenAIRE

Zhang Yuan; Li Ming-De; Zhang Hong-Bang

2017-01-01

The rapid development of media technology makes the modern society become a “social media” or even “over social media”, the rise of social media makes it beyond the tool attribute, and become an important force in the reconstruction of contemporary society, the risk of concomitant. The anomie and breach of Social media regularly staged, weakened its positive social function, forcing us to think about the social responsibility of social media,which are reflections on the lack of responsibility...

Understanding Social Media Logic

Directory of Open Access Journals (Sweden)

José van Dijck

2013-08-01

Full Text Available Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media logic—the norms, strategies, mechanisms, and economies—underpin­ning its dynamics. This logic will be considered in light of what has been identified as mass me­dia logic, which has helped spread the media's powerful discourse outside its institutional boundaries. Theorizing social media logic, we identify four grounding principles—programmabil­ity, popularity, connectivity, and datafication—and argue that these principles become increas­ingly entangled with mass media logic. The logic of social media, rooted in these grounding principles and strategies, is gradually invading all areas of public life. Besides print news and broadcasting, it also affects law and order, social activism, politics, and so forth. Therefore, its sustaining logic and widespread dissemination deserve to be scrutinized in detail in order to better understand its impact in various domains. Concentrating on the tactics and strategies at work in social media logic, we reassess the constellation of power relationships in which social practices unfold, raising questions such as: How does social media logic modify or enhance ex­isting mass media logic? And how is this new media logic exported beyond the boundaries of (social or mass media proper? The underlying principles, tactics, and strategies may be relat­ively simple to identify, but it is much harder to map the complex connections between plat­forms that distribute this logic: users that employ them, technologies that

Tumour vasculature immaturity, oxidative damage and systemic inflammation stratify survival of colorectal cancer patients on bevacizumab treatment

Science.gov (United States)

Martin, Petra; Biniecka, Monika; Ó'Meachair, Shane; Maguire, Aoife; Tosetto, Miriam; Nolan, Blathnaid; Hyland, John; Sheahan, Kieran; O'Donoghue, Diarmuid; Mulcahy, Hugh; Fennelly, David; O'Sullivan, Jacintha

2018-01-01

Despite treatment of patients with metastatic colorectal cancer (mCRC) with bevacizumab plus chemotherapy, response rates are modest and there are no biomarkers available that will predict response. The aim of this study was to assess if markers associated with three interconnected cancer-associated biological processes, specifically angiogenesis, inflammation and oxidative damage, could stratify the survival outcome of this cohort. Levels of angiogenesis, inflammation and oxidative damage markers were assessed in pre-bevacizumab resected tumour and serum samples of mCRC patients by dual immunofluorescence, immunohistochemistry and ELISA. This study identified that specific markers of angiogenesis, inflammation and oxidative damage stratify survival of patients on this anti-angiogenic treatment. Biomarkers of immature tumour vasculature (% IMM, p=0.026, n=80), high levels of oxidative damage in the tumour epithelium (intensity of 8-oxo-dG in nuclear and cytoplasmic compartments, p=0.042 and 0.038 respectively, n=75) and lower systemic pro-inflammatory cytokines (IL6 and IL8, p=0.053 and 0.049 respectively, n=61) significantly stratify with median overall survival (OS). In summary, screening for a panel of biomarkers for high levels of immature tumour vasculature, high levels of oxidative DNA damage and low levels of systemic pro-inflammatory cytokines may be beneficial in predicting enhanced survival outcome following bevacizumab treatment for mCRC. PMID:29535825

The Media Reader.

Science.gov (United States)

Valdes, Joan; Crow, Jeanne

An anthology of readings in the media correlates chapter-by-chapter to the authors' textbook, "The Media Works." Fifteen chapters cover the study of newspapers, magazines, comics, popular music, television, movies, and advertising. The authors included represent varied perspectives on the media. The selections were chosen with the help of a…

Juggling with media : The consequences of media multitasking for adolescent development

NARCIS (Netherlands)

van der Schuur, W.A.

2018-01-01

More than ever, adolescents juggle with media. They use multiple media simultaneously, for example, they send text messages to their friends while watching a movie. In addition, they use media during academic and social activities, such as watching YouTube videos while doing homework. Although this

Mixed-Media File Systems

NARCIS (Netherlands)

Bosch, H.G.P.

1999-01-01

This thesis addresses the problem of implementing mixed-media storage systems. In this work a mixed-media file system is defined to be a system that stores both conventional (best-effort) file data and real-time continuous-media data. Continuous-media data is usually bulky, and servers storing and

PERIKLANAN DALAM MEDIA BARU (Advertising In The New Media )

OpenAIRE

Errika Dwi Setya Watie

2016-01-01

Advertising is currently getting a huge challenge. the number of ads , it is realized or not, effects on saturation of advertising. New era media presents new communications media to the community. This condition should be recognized by anyone working in the advertising, because the development of advertising is in line with a new media movement, so the expectansy of the intended market segment will be achieved better. Today, the challenge of a new style of advertising has been answered b...

Measuring media multitasking : Development of a short measure of media multitasking for adolescents

NARCIS (Netherlands)

Baumgartner, Susanne E.; Lemmens, Jeroen S.; Weeda, Wouter D.; Huizinga, Mariette

2017-01-01

Although media multitasking is an increasingly occurring form of media use, there are currently no validated, short instruments to measure media multitasking among adolescents. The aim of the present study, therefore, was to develop a short media multitasking measure for adolescents (MMM-S). Two

Promoting Media Literacy’ as Practicing “Media Reform”: Reflecting on Personal Experiences

Directory of Open Access Journals (Sweden)

Hui-Ju Tsai

2016-04-01

Full Text Available This paper assesses conceptions and practices in critical media literacy. In particular, it focuses on teaching experience and the processes which combine the educator’s reflection of theories of the ‘public sphere’, ‘media literacy’, and ‘communication civil rights’. The paper is divided into three main parts. The first of four sections will briefly cover the history of media reform and the relationship between the media reform movement and critical media literacy lessons in community colleges. It will connect this to the idea of ‘turn to the public’. The meaning and position of ‘media literacy’ in the broad media reform movement will also be analyzed. Following this, in the second section, conceptualizations of the ‘public sphere’, ‘public pedagogy’, and ‘critical media literacy pedagogy’ will be developed. Finally, three stages of the lesson design and practical interactions will be examined dialectically. In particular, the community college field research on my teaching experience will be described in the third section, and the suggestions, reflections and conclusions from the research will be examined in the last section.

Mediating social media use : connecting parents mediation strategies and social media literacy

OpenAIRE

Daneels, Rowan; Vanwynsberghe, Hadewijch

2017-01-01

Abstract: Increasingly complex and multipurpose social media platforms require digital competences from parents and adolescents alike. While adolescents grow up with social media, parents have more difficulties with them, leading to uncertainties regarding their adolescents social media mediation. This study contributes to parental mediation research by (1) investigating whether mediation strategies defined by previous research are also relevant for social media use, and (2) exploring whether...

Children's media policy.

Science.gov (United States)

Jordan, Amy B

2008-01-01

Amy Jordan addresses the need to balance the media industry's potentially important contributions to the healthy development of America's children against the consequences of excessive and age-inappropriate media exposure. Much of the philosophical tension regarding how much say the government should have about media content and delivery stems from the U.S. Constitution's First Amendment protection against government interference in free speech, including commercial speech. Courts, Jordan says, have repeatedly had to weigh the rights of commercial entities to say what they please against the need to protect vulnerable citizens such as children. This balancing act is complicated even further, she says, because many government regulations apply only to broadcast television and not to non-broadcast media such as the Internet or cable television, though Congress has addressed the need to protect children's privacy online. The need to protect both free speech and children has given rise to a fluid media policy mix of federal mandates and industry self-regulation. Jordan describes the role of the three branches of the federal government in formulating and implementing media policy. She also notes the jockeying for influence in policymaking by industry lobbies, child advocacy groups, and academic researchers. The media industry itself, says Jordan, is spurred to self-regulation when public disapproval grows severe enough to raise the possibility of new government action. Jordan surveys a range of government and industry actions, from legislatively required parental monitoring tools, such as the V-Chip blocking device on television sets, to the voluntary industry ratings systems governing television, movies, and video games, to voluntary social website disclosures to outright government bans, such as indecency and child privacy information collection. She considers the success of these efforts in limiting children's exposure to damaging content and in improving parents

The Indirect Boundary Element Method (IBEM) for Seismic Response of Topographical Irregularities in Layered Media

Science.gov (United States)

Contreras Zazueta, M. A.; Perton, M.; Sanchez-Sesma, F. J.; Sánchez-Alvaro, E.

2013-12-01

The seismic hazard assessment of extended developments, such as a dam, a bridge or a pipeline, needs the strong ground motion simulation taking into account the effects of surface geology. In many cases the incoming wave field can be obtained from attenuation relations or simulations for layered media using Discrete Wave Number (DWN). Sometimes there is a need to include in simulations the seismic source as well. A number of methods to solve these problems have been developed. Among them the Finite Element and Finite Difference Methods (FEM and FDM) are generally preferred because of the facility of use. Nevertheless, the analysis of realistic dynamic loading induced by earthquakes requires a thinner mesh of the entire domain to consider high frequencies. Consequently this may imply a high computational cost. The Indirect Boundary Element Method (IBEM) can also be employed. Here it is used to study the response of a site to historical seismic activity. This method is particularly suited to model wave propagation through wide areas as it requires only the meshing of boundaries. Moreover, it is well suited to represent finely the diffraction that can occur on a fault. However, the IBEM has been applied mainly to simple geometrical configurations. In this communication significant refinements of the formulation are presented. Using IBEM we can simulate wave propagation in complex geometrical configurations such as a stratified medium crossed by thin faults or having a complex topography. Two main developments are here described; one integrates the DWN method inside the IBEM in order to represent the Green's functions of stratified media with relatively low computational cost but assuming unbounded parallel flat layers, and the other is the extension of IBEM to deal with multi-regions in contact which allows more versatility with a higher computational cost compared to the first one but still minor to an equivalent FEM formulation. The two approaches are fully

Yield and quality of ground water from stratified-drift aquifers, Taunton River basin, Massachusetts : executive summary

Science.gov (United States)

Lapham, Wayne W.; Olimpio, Julio C.

1989-01-01

Water shortages are a chronic problem in parts of the Taunton River basin and are caused by a combination of factors. Water use in this part of the Boston metropolitan area is likely to increase during the next decade. The Massachusetts Division of Water Resources projects that about 50% of the cities and towns within and on the perimeter of the basin may have water supply deficits by 1990 if water management projects are not pursued throughout the 1980s. Estimates of the long-term yield of the 26 regional aquifers indicate that the yields of the two most productive aquifers equal or exceed 11.9 and 11.3 cu ft/sec, 90% of the time, respectively, if minimum stream discharge is maintained at 99.5% flow duration. Eighteen of the 26 aquifers were pumped for public water supply during 1983. Further analysis of the yield characteristics of these 18 aquifers indicates that the 1983 pumping rate of each of these 18 aquifers can be sustained at least 70% of the time. Selected physical properties and concentrations of major chemical constituents in groundwater from the stratified-drift aquifers at 80 sampling sites were used to characterize general water quality in aquifers throughout the basin. The pH of the groundwater ranged from 5.4 to 7.0. Natural elevated concentrations of Fe and Mn in water in the stratified-drift aquifers are present locally in the basin. Natural concentrations of these two metals commonly exceed the limits of 0.3 mg/L for Fe and 0.05 mg/L for Mn recommended for drinking water. Fifty-one analyses of selected trace metals in groundwater samples from stratified-drift aquifers throughout the basin were used to characterize trace metal concentrations in the groundwater. Of the 10 constituents sampled that have US EPA limits recommended for drinking water, only the Pb concentration in water at one site (60 micrograms/L) exceeded the recommended limit of 50 micrograms/L. Analyses of selected organic compounds in water in the stratified-drift aquifers at 74

Balancing media environments

DEFF Research Database (Denmark)

Olesen, Mogens

The paper examines how students in Danish upper secondary schools experience the uses and effects of the digital environment in relation to their school activities. Theoretically a media ecological perspective (Strate 2006) is applied which understands teaching and learning practices as shaped...... by the interrelation between teacher, student and the media technologies. According to this perspective, media creates an environment that shapes our possibilities for acting and communicating. In a basic sense, teaching and learning is a communicative situation where, traditionally, the teacher sends information...... to the receiving students through a medium (e.g. speech, blackboard, book or online learning platform). Digital media challenge this situation due to their affordances (Gibson 1979) for interactivity. Affordance has become an increasingly popular term within media studies for describing a complementary...

Design and simulation of stratified probability digital receiver with application to the multipath communication

Science.gov (United States)

Deal, J. H.

1975-01-01

One approach to the problem of simplifying complex nonlinear filtering algorithms is through using stratified probability approximations where the continuous probability density functions of certain random variables are represented by discrete mass approximations. This technique is developed in this paper and used to simplify the filtering algorithms developed for the optimum receiver for signals corrupted by both additive and multiplicative noise.

Social media influencer marketing

OpenAIRE

Isosuo, Heli

2016-01-01

The marketing field is changing simultaneously with the digital world. Social media is getting more and more important to marketers, and there is a need to stand out in the social media noise. Social media influencer marketing could be a good alternative to other types of marketing. A need from the consignor and the interest of the author were the motivations for conducting the study. Sääskilahti Consulting has a social media influencer network Somevaikuttajat, which is offering social media ...

Media Convergence: the Culture Dimensions of Thinking%Media Convergence:the Culture Dimensions of Thinking

Institute of Scientific and Technical Information of China (English)

Shen Diao; Lan Ju

2017-01-01

In the process of meida Convergence,many researchers paid excessive attention to media technology,industry and management,and ignored the culture dimensions of media convergence.Therefore,to transcend media convergence technology,industrial thinking and more to the particularity attach importance to cultural media,it is a right way to achieve media convergence.But in the context of China's culture,media convergence should value the cultural uniqueness and the imbalance of the realistic problems,to reach innovation and breakthrough.

Risk-stratifying capacity of PET/CT metabolic tumor volume in stage IIIA non-small cell lung cancer

Energy Technology Data Exchange (ETDEWEB)

Finkle, Joshua H.; Jo, Stephanie Y.; Yuan, Cindy; Pu, Yonglin [University of Chicago, Department of Radiology, Chicago, IL (United States); Ferguson, Mark K. [University of Chicago, Department of Surgery, Chicago, IL (United States); Liu, Hai-Yan [First Hospital of Shanxi Medical University, Department of Nuclear Medicine, Taiyuan, Shanxi (China); Zhang, Chenpeng [Shanghai Jiao Tong University, Department of Nuclear Medicine, RenJi Hospital, School of Medicine, Shanghai (China); Zhu, Xuee [Nanjing Medical University, Department of Radiology, BenQ Medical Center, Nanjing, Jiangsu Province (China)

2017-08-15

Stage IIIA non-small cell lung cancer (NSCLC) is heterogeneous in tumor burden, and its treatment is variable. Whole-body metabolic tumor volume (MTV{sub WB}) has been shown to be an independent prognostic index for overall survival (OS). However, the potential of MTV{sub WB} to risk-stratify stage IIIA NSCLC has previously been unknown. If we can identify subgroups within the stage exhibiting significant OS differences using MTV{sub WB}, MTV{sub WB} may lead to adjustments in patients' risk profile evaluations and may, therefore, influence clinical decision making regarding treatment. We estimated the risk-stratifying capacity of MTV{sub WB} in stage IIIA by comparing OS of stratified stage IIIA with stage IIB and IIIB NSCLC. We performed a retrospective review of 330 patients with clinical stage IIB, IIIA, and IIIB NSCLC diagnosed between 2004 and 2014. The patients' clinical TNM stage, initial MTV{sub WB}, and long-term survival data were collected. Patients with TNM stage IIIA disease were stratified by MTV{sub WB}. The optimal MTV{sub WB} cutoff value for stage IIIA patients was calculated using sequential log-rank tests. Univariate and multivariate cox regression analyses and Kaplan-Meier OS analysis with log-rank tests were performed. The optimal MTV{sub WB} cut-point was 29.2 mL for the risk-stratification of stage IIIA. We identified statistically significant differences in OS between stage IIB and IIIA patients (p < 0.01), between IIIA and IIIB patients (p < 0.01), and between the stage IIIA patients with low MTV{sub WB} (below 29.2 mL) and the stage IIIA patients with high MTV{sub WB} (above 29.2 mL) (p < 0.01). There was no OS difference between the low MTV{sub WB} stage IIIA and the cohort of stage IIB patients (p = 0.485), or between the high MTV{sub WB} stage IIIA patients and the cohort of stage IIIB patients (p = 0.459). Similar risk-stratification capacity of MTV{sub WB} was observed in a large range of cutoff values from 15 to 55 mL in

Impact of European Media Education Strategies on Russian Media Education Development

Science.gov (United States)

Mikhaleva, Galina V.

2015-01-01

The article attempts to examine the impact of European media education theories and approaches on Russian media education evolution basing on a comparative analysis of Russian and European media literacy promotion strategies in the historical context. This influence resulted in the appearance and development of socio-cultural models of media…

Pengembangan Media Pembelajaran Berupa Komik Fisika Berbantuan Sosial Media Instagram sebagai Alternatif Pembelajaran

Directory of Open Access Journals (Sweden)

Irwandani Irwandani

2016-04-01

Full Text Available The development trend of technology and information at this time should be used by the world of education to make it as a learning tool, both outside and inside the classroom. One trend that is emerging now is the use of social media as a medium of learning. Social media will be focused to develop is a media Instagram, in which can contain images and text content. The study was conducted with the aim of producing instructional media products that meet the necessary criteria. The research is the research and development method undertaken by several stages, a preliminary investigation, gathering information, product design, product validation, testing is limited to the user, and product revision. Based on the stages that made learning media product obtained declared fit and is needed by learners after validating and testing the product. Validation linguists gained 84%, the design of 82.67%, 86.67% materials, and media gained 87.14%. Meanwhile, based on the scoring is obtained 90.83%. Tren perkembangan teknologi dan informasi saat ini seharusnya bisa dimanfaatkan oleh dunia pendidikan untuk menjadikannya sebagai sarana pembelajaran, baik itu di luar maupun di dalam kelas. Salah satu tren yang sedang muncul saat ini adalah pemanfaatan media sosial sebagai media pembelajaran. Media sosial yang akan difokuskan untuk dikembangkan adalah media instagram, yang di dalamnya bisa memuat konten gambar dan tulisan. Penelitian dilakukan dengan tujuan menghasilkan produk media pembelajaran yang memenuhi kriteria yang dibutuhkan. Penelitian yang digunakan adalah penelitian dan pengembangan yang dilakukan dengan beberapa tahap yaitu melakukan penelitian pendahuluan, mengumpulkan informasi, desain produk, validasi produk, ujicoba terbatas kepada pengguna, kemudian revisi produk. Berdasarkan tahapan-tahapan yang dilakukan diperoleh produk media pembelajaran yang dinyatakan layak dan sangat dibutuhkan oleh peserta didik setelah melakukan validasi

The association between use of electronic media and prevalence of headache in adolescents: results from a population-based cross-sectional study

Directory of Open Access Journals (Sweden)

Straube Andreas

2010-02-01

Full Text Available Abstract Background Use of electronic media, i.e. mobile phones, computers, television, game consoles or listening to music, is very common, especially amongst adolescents. There is currently a debate about whether frequent use of these media might have adverse effects on health, especially on headaches, which are among the most-reported health complaints in adolescents. The aim of the present study was to assess associations between frequent use of electronic media and the prevalence of different types of headache in adolescents. Methods Data were derived from a population-based sample (n = 1,025, ages 13-17 years. Type of headache (i.e. migraine, tension-type headache, unclassifiable headache was ascertained by standardized questionnaires for subjects reporting headache episodes at least once per month during the last six months. Duration of electronic media use was assessed during personal interviews. Associations were estimated with logistic regression models adjusted for age group, sex, family condition and socio-economic status. Results Most of the adolescents used computers (85%, watched television (90% or listened to music (90% daily, otherwise only 23% of the participants used their mobile phones and only 25% played with game consoles on a daily basis. A statistically significant association between listening to music and any headache (odds ratio 1.8; 95% confidence interval 1.1-3.1 for 30 minutes per day, 2.1; 1.2-3.7 for 1 to 2 hours per day; 2.0; 1.2-3.5 for 3 hours and longer listening to music per day was observed. When stratifying for type of headache, no statistically significant association was seen. Conclusions Apart from an association between listening to music on a daily basis and overall headache, no consistent associations between the use of electronic media and different types of headache were observed.

The association between use of electronic media and prevalence of headache in adolescents: results from a population-based cross-sectional study.

Science.gov (United States)

Milde-Busch, Astrid; von Kries, Rüdiger; Thomas, Silke; Heinrich, Sabine; Straube, Andreas; Radon, Katja

2010-02-09

Use of electronic media, i.e. mobile phones, computers, television, game consoles or listening to music, is very common, especially amongst adolescents. There is currently a debate about whether frequent use of these media might have adverse effects on health, especially on headaches, which are among the most-reported health complaints in adolescents. The aim of the present study was to assess associations between frequent use of electronic media and the prevalence of different types of headache in adolescents. Data were derived from a population-based sample (n = 1,025, ages 13-17 years). Type of headache (i.e. migraine, tension-type headache, unclassifiable headache) was ascertained by standardized questionnaires for subjects reporting headache episodes at least once per month during the last six months. Duration of electronic media use was assessed during personal interviews. Associations were estimated with logistic regression models adjusted for age group, sex, family condition and socio-economic status. Most of the adolescents used computers (85%), watched television (90%) or listened to music (90%) daily, otherwise only 23% of the participants used their mobile phones and only 25% played with game consoles on a daily basis. A statistically significant association between listening to music and any headache (odds ratio 1.8; 95% confidence interval 1.1-3.1 for 30 minutes per day, 2.1; 1.2-3.7 for 1 to 2 hours per day; 2.0; 1.2-3.5 for 3 hours and longer listening to music per day) was observed. When stratifying for type of headache, no statistically significant association was seen. Apart from an association between listening to music on a daily basis and overall headache, no consistent associations between the use of electronic media and different types of headache were observed.

From hybrid-media system to hybrid-media politicians

DEFF Research Database (Denmark)

Blach-Ørsten, Mark; Eberholst, Mads Kæmsgaard; Burkal, Rasmus

2017-01-01

’ media use is changing rapidly; 15%–16% of Danish candidates used Twitter in 2011 but 68% in 2015. In this large-sample content analysis, party leaders have high traditional-news-media and low Twitter presence, and younger candidates visa-versa, but some politicians have high presence in both. Hybrid...

Your Media Speak So Loud I Can't Hear a Word You're Saying: Impact of Media and Media Selection on Performance

Science.gov (United States)

Hassell, Martin

2013-01-01

With the proliferation of communication media and technologies available, it is important for teams to understand the influence of these media on the performance of their communications. Additionally, it is important for researchers to understand how teams choose and use media. Literature on communication media impacts and communication…

Critical Media Literacy in Action: Uniting Theory, Practice and Politics in Media Education

Science.gov (United States)

Thevenin, Benjamin Joseph

2012-01-01

As media literacy is a growing field, there exist a number of distinct approaches to media education with varied political significance. Approaches such as protectionism, media arts education, and critical media literacy draw upon diverse theoretical traditions. Often overlooked in these traditions is the Critical Theory of the Frankfurt School.…

Abortion in the media.

Science.gov (United States)

Conti, Jennifer A; Cahill, Erica

2017-12-01

To review updates in how abortion care is depicted and analysed though various media outlets: news, television, film, and social media. A surge in recent media-related abortion research has recognized several notable and emerging themes: abortion in the news media is often inappropriately sourced and politically motivated; abortion portrayal in US film and television is frequently misrepresented; and social media has a new and significant role in abortion advocacy. The portrayal of abortion onscreen, in the news, and online through social media has a significant impact on cultural, personal, and political beliefs in the United States. This is an emerging field of research with wide spread potential impact across several arenas: medicine, policy, public health.

Premixing and steam explosion phenomena in the tests with stratified melt-coolant configuration and binary oxidic melt simulant materials

Energy Technology Data Exchange (ETDEWEB)

Kudinov, Pavel, E-mail: pavel@safety.sci.kth.se; Grishchenko, Dmitry, E-mail: dmitry@safety.sci.kth.se; Konovalenko, Alexander, E-mail: kono@kth.se; Karbojian, Aram, E-mail: karbojan@kth.se

2017-04-01

Highlights: • Steam explosion in stratified melt-coolant configuration is studied experimentally. • Different binary oxidic melt simulant materials were used. • Five spontaneous steam explosions were observed. • Instability of melt-coolant interface and formation of premixing layer was observed. • Explosion strength is influenced by melt superheat and water subcooling. - Abstract: Steam explosion phenomena in stratified melt-coolant configuration are considered in this paper. Liquid corium layer covered by water on top can be formed in severe accident scenarios with (i) vessel failure and release of corium melt into a relatively shallow water pool; (ii) with top flooding of corium melt layer. In previous assessments of potential energetics in stratified melt-coolant configuration, it was assumed that melt and coolant are separated by a stable vapor film and there is no premixing prior to the shock wave propagation. This assumption was instrumental for concluding that the amount of energy that can be released in such configuration is not of safety importance. However, several recent experiments carried out in Pouring and Under-water Liquid Melt Spreading (PULiMS) facility with up to 78 kg of binary oxidic corium simulants mixtures have resulted in spontaneous explosions with relatively high conversion ratios (order of one percent). The instability of the melt-coolant interface, melt splashes and formation of premixing layer were observed in the tests. In this work, we present results of experiments carried out more recently in steam explosion in stratified melt-coolant configuration (SES) facility in order to shed some light on the premixing phenomena and assess the influence of the test conditions on the steam explosion energetics.

Media Anthropology: A Theoretical Framework

Science.gov (United States)

Eiselein, E. B.; Topper, Martin

1976-01-01

Media anthropology, a diverse field, has involved nearly all the major subdisciplines of anthropology and most of the major media in five different areas of interaction: the study of media, reaching the public, gathering data, teaching with media, and applied media anthropology. (NQ)

Potentials of Social Media as Media Facility of Tourism Promotion Based on Community Participation

OpenAIRE

Romadhan, Mohammad Insan; Rusmana, Dewi Sri Andika

2018-01-01

The potential of social media as a media of tourism promotion is vastly massive. Nevertheless, the problem is on how to get social media can be widely known and has abundant followers for the publicized content could be accepted by the crowd. Normally, social media of a tourism promotion is integrated with conventional media like television, radio and newspapers. What if a region does not have large funds to interact with the conventional media, such issue be overcome with community participa...

Media multitasking in adolescence.

Science.gov (United States)

Cain, Matthew S; Leonard, Julia A; Gabrieli, John D E; Finn, Amy S

2016-12-01

Media use has been on the rise in adolescents overall, and in particular, the amount of media multitasking-multiple media consumed simultaneously, such as having a text message conversation while watching TV-has been increasing. In adults, heavy media multitasking has been linked with poorer performance on a number of laboratory measures of cognition, but no relationship has yet been established between media-multitasking behavior and real-world outcomes. Examining individual differences across a group of adolescents, we found that more frequent media multitasking in daily life was associated with poorer performance on statewide standardized achievement tests of math and English in the classroom, poorer performance on behavioral measures of executive function (working memory capacity) in the laboratory, and traits of greater impulsivity and lesser growth mindset. Greater media multitasking had a relatively circumscribed set of associations, and was not related to behavioral measures of cognitive processing speed, implicit learning, or manual dexterity, or to traits of grit and conscientiousness. Thus, individual differences in adolescent media multitasking were related to specific differences in executive function and in performance on real-world academic achievement measures: More media multitasking was associated with poorer executive function ability, worse academic achievement, and a reduced growth mindset.

Identification of distinct layers within the stratified squamous epithelium of the adult human true vocal fold.

Science.gov (United States)

Dowdall, Jayme R; Sadow, Peter M; Hartnick, Christopher; Vinarsky, Vladimir; Mou, Hongmei; Zhao, Rui; Song, Phillip C; Franco, Ramon A; Rajagopal, Jayaraj

2015-09-01

A precise molecular schema for classifying the different cell types of the normal human vocal fold epithelium is lacking. We hypothesize that the true vocal fold epithelium has a cellular architecture and organization similar to that of other stratified squamous epithelia including the skin, cornea, oral mucosa, and esophagus. In analogy to disorders of the skin and gastrointestinal tract, a molecular definition of the normal cell types within the human vocal fold epithelium and a description of their geometric relationships should serve as a foundation for characterizing cellular changes associated with metaplasia, dysplasia, and cancer. Qualitative study with adult human larynges. Histologic sections of normal human laryngeal tissue were analyzed for morphology (hematoxylin and eosin) and immunohistochemical protein expression profile, including cytokeratins (CK13 and CK14), cornified envelope proteins (involucrin), basal cells (NGFR/p75), and proliferation markers (Ki67). We demonstrated that three distinct cell strata with unique marker profiles are present within the stratified squamous epithelium of the true vocal fold. We used these definitions to establish that cell proliferation is restricted to certain cell types and layers within the epithelium. These distinct cell types are reproducible across five normal adult larynges. We have established that three layers of cells are present within the normal adult stratified squamous epithelium of the true vocal fold. Furthermore, replicating cell populations are largely restricted to the parabasal strata within the epithelium. This delineation of distinct cell populations will facilitate future studies of vocal fold regeneration and cancer. N/A. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Including Media in Field Research and Becoming Part of the Science Media

Science.gov (United States)

Pelto, M. S.

2015-12-01

There are two primary strategies that I have pursued over the last decade to engage the media, policy makers, and public; after two decades of typical scientific publication methods. An effective method to engage the media with our ongoing 32 year glacier field research program has been to invite media members to join us in the field. From climate videographers to traditional reporters we have had a member of the media with us in nine of the last ten field seasons; two in 2015. The resulting stories have led to several awards for the journalists and an ongoing relationship with our research program. The second part of this science research communication strategy is to have readily available material on specific topics for the media to utilize; this requires social media outreach. The primary outlet media find is the AGU Blog: From a Glacier's Perspective. This blog pubishes two articles a week on a specific glacier's response to climate change. The blog yields on average a media contact on every fourth blog post in 2015. The contacts revolve around specific local glacier information published on the blog. The goal of each blog post is to tell a story about how each glacier is impacted by climate change.

Open Media Science

DEFF Research Database (Denmark)

Møller Moltke Martiny, Kristian; Pedersen, David Budtz; Hansted, Allan Alfred Birkegaard

2016-01-01

In this article, we present three challenges to the emerging Open Science (OS) movement: the challenge of communication, collaboration and cultivation of scientific research. We argue that to address these challenges OS needs to include other forms of data than what can be captured in a text...... and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...... of using open media to face the challenges of OS....

Developing an Ethics of Youth Media Production Using Media Literacy, Identity, and Modality

Science.gov (United States)

Gibbons, Damiana

2012-01-01

This critical, theoretical paper conceptualizes what determines an ethics for youth media production. Through discussions of media literacy, identity, and multimodality, I attempt to shift the question away from "What are the ethical ways in which youth use media?" toward the question "What are the ethics we have created as media literacy…

Transnational orientations in a global media landscape: Youth, media, war and conflict

Directory of Open Access Journals (Sweden)

Elisabeth Eide

2014-04-01

Full Text Available This article reflects on the role of media in the re-imagination and reproduction (reconstruction of Norwegian identities and communities with a particular focus on how young people within diasporas follow news on war and conflict in their (or their parents’ countries of origin. The research employs focus groups with young people from the Pakistani, Afghan, and Tamil Diasporas, and also online surveys. The three groups share the experience of trying to build a life in another country (Norway, while their family and friends in the “homeland” experience political violence and civil war. We identify a notable sense of frustration and skepticism towards Norwegian media. The informants actively use international media and media from the homeland, and often find these more reliable and providing more relevant information than Norwegian media. They also voice a strong critique of the ways in which the media react when “the others” are victims of violence, and several participants react negatively towards the neglect of positive reporting from their respective homelands, and to media hostility towards Muslims.

Transverse thermopherotic MHD Oldroyd-B fluid with Newtonian heating

Science.gov (United States)

Mehmood, R.; Rana, S.; Nadeem, S.

2018-03-01

Hydromagnetic transverse flow of an Oldroyd-B type fluid with suspension of nanoparticles and Newtonian heating effects is conferred in this article. Relaxation and Retardation time effects are taken into consideration. Using suitable transformations physical problem is converted into non-linear ordinary differential equations which are tackled numerically via Runge-Kutta Fehlberg integration scheme. Illustration of embedded constraints on flow characteristics are extracted through graphs. The physical response of velocity, temperature and concentration are investigated computationally. Momentum boundary layer thickness decreases but local heat and mass flux rises for Deborah number and Hartman number. The results provide interesting insights into certain applicable transport phenomena involving hydromagnetic rheological fluids.

Social Media as Collaborative Media in Workplace Learning

Science.gov (United States)

Thomas, Kristopher J.; Akdere, Mesut

2013-01-01

As a result of rapid changes in technology, much is discussed about the use of social media in branding, marketing, and in general corporate communications. The intensity with which social media tools--blogs, wikis, Twitter, instant messaging (IM) and Facebook, among others--have proliferated is staggering. Increasingly important is the role of…

Transport in Stochastic Media

International Nuclear Information System (INIS)

Haran, O.; Shvarts, D.; Thieberger, R.

1998-01-01

Classical transport of neutral particles in a binary, scattering, stochastic media is discussed. It is assumed that the cross-sections of the constituent materials and their volume fractions are known. The inner structure of the media is stochastic, but there exist a statistical knowledge about the lump sizes, shapes and arrangement. The transmission through the composite media depends on the specific heterogeneous realization of the media. The current research focuses on the averaged transmission through an ensemble of realizations, frm which an effective cross-section for the media can be derived. The problem of one dimensional transport in stochastic media has been studied extensively [1]. In the one dimensional description of the problem, particles are transported along a line populated with alternating material segments of random lengths. The current work discusses transport in two-dimensional stochastic media. The phenomenon that is unique to the multi-dimensional description of the problem is obstacle bypassing. Obstacle bypassing tends to reduce the opacity of the media, thereby reducing its effective cross-section. The importance of this phenomenon depends on the manner in which the obstacles are arranged in the media. Results of transport simulations in multi-dimensional stochastic media are presented. Effective cross-sections derived from the simulations are compared against those obtained for the one-dimensional problem, and against those obtained from effective multi-dimensional models, which are partially based on a Markovian assumption

Social Media Reputation

DEFF Research Database (Denmark)

Etter, Michael; Colleoni, Elanor; Ravasi, Davide

directly to corporate performance and actions. Secondly, prominent reputation measurements couple stakeholders´ believes to reputation drivers through the use of predefined scales and items. We argue that with the rise of social media a company´s reputation has increasingly become autonomous from corporate...... actions, which demands a greater decoupling of stakeholders´ perceptions from corporate signals or actions in corporate reputation research. We develop the concept of social media reputation as the overall evaluation of a company presented in social media and present a new approach of measuring reputation...... based on social media data that accounts for the autonomy of stakeholder´s perception of a firm. We compare and contrast this novel social media reputation measure (SMRM) with traditional reputation measurements and find that SMRM is a valuable measurement to capture the autonomy of the stakeholders...

Internet and Cross Media Productions

DEFF Research Database (Denmark)

Petersen, Anja Bechmann

2006-01-01

, the Internet continues to play a minor role when compared to older media. The content of the cross media concepts and organizations' history are crucial elements in deciding the priority and use of platforms. Methodologically, the article approaches cross media and the roles of the Internet on a micro......Convergence is one of the hot topics in Internet studies. Recently, however, media organizations have turned their focus to cross media communication. Media organizations are interested in optimizing communication across platforms such as TV, radio, websites, mobile telephones and newspapers....... The aim of this article is to examine the roles of the Internet when emphasis is put on cross media rather than convergence. This article proposes not one unidirectional convergent tendency but manifold roles of the Internet in cross media communication. Inside the media organizations, however...

Psychological career resources, career adaptability and work engagement of generational cohorts in the media industry

Directory of Open Access Journals (Sweden)

Melinde Coetzee

2017-11-01

Full Text Available Orientation: The global skills crisis coupled with the aging workforce, rapid technological advances and changing nature of work have infringed various challenges upon organisations and employees. Media organisations in particular are affected by these trends, with retention further at risk because of the specialised and scarce skills sought and the versatility and ambiguity inherent in the nature of careers within the media industry, therefore resulting in engagement and skills retention being high on the agenda. Research purpose: The aim of the study was to explore whether employees’ age, psychological career resources and career adaptability significantly predict their work engagement and whether generational cohorts differ significantly regarding these variables. Motivation for the study: Within a retention context, it is important to gain insight into the employees’ personal career-related capabilities and dispositions as these are deemed important for driving career development and engagement levels, which, in turn, impact on the retention of talent. Research design, approach and method: A stratified random sample (N = 248 of predominantly female (63.3% and black African people (54% within their early career stages (80% < 45 years was used. A cross-sectional, quantitative research design approach was followed. Stepwise regression analyses and tests for significant mean differences were performed. Main findings: The results indicated generational cohort (age, career confidence (career adaptability and career harmonisers (psychological career resources as significant predictors of work engagement. The Generation Y individuals had higher levels of psychological career resources (career preferences, career values and career drivers, while the Generation X individuals had higher career curiosity. The Baby Boomers showed higher levels of work engagement. Practical and managerial implications: Psycho-social career meta-capacities positively

Social Media Marketing in Russia

OpenAIRE

Olgskaya, Kristina

2017-01-01

Social media marketing involves the use of social media for connecting with prospective consumers. The study focuses on explaining such notions like social media marketing (SMM), types of SMM, differences between social media and traditional marketing, social media marketing plan, development ways of strategic social media marketing plan and why strategy may fail. This thesis also presents research in Russian social network – Vkontakte, where promotion of Mechanical Engineering programme ...

Breaking Open the Black Boxes: media archaeology, anarchaeology and media materiality

OpenAIRE

Goddard, M.

2015-01-01

An essay on the emergent methodology of media archaeology, in realtion to the material turn in approaches to digital media. In particular, this article advocates taking up Siegfried Zielinski's concept of 'anarchaeology', but in a different sense to the way it was originally proposed, in order to emphasise the political potentials of a media (an)archaeological methodological approach.

Up-scaling of a two-phase flow model including gravity effect in geological heterogeneous media: application to CO2 sequestration

International Nuclear Information System (INIS)

Ngo, Tri-Dat

2016-01-01

This work deals with the mathematical modeling and the numerical simulation of the migration under gravity and capillarity effects of the supercritical CO 2 injected into a geological heterogeneous sequestration site. The simulations are performed with the code DuMux. Particularly, we consider the up-scaling, from the cell scale to the reservoir scale, of a two-phase (CO 2 -brine) flow model within a periodic stratified medium made up of horizontal low permeability barriers, continuous or discontinuous. The up-scaling is done by the two-scale asymptotic method. First, we consider perfectly layered media. An homogenized model is developed and validated by numerical simulation for different values of capillary number and the incident flux of CO 2 . The homogenization method is then applied to the case of a two-dimensional medium made up of discontinuous layers. Due to the gravity effect, the CO 2 accumulates under the low permeability layers, which leads to a non-standard local mathematical problem. This stratification is modeled using the gravity current approach. This approach is then extended to the case of semi-permeable strata taking into account the capillarity. The up-scaled model is compared with numerical simulations for different types of layers, with or without capillary pressure, and its limit of validity is discussed in each of these cases. The final part of this thesis is devoted to the study of the parallel computing performances of the code DuMux to simulate the injection and migration of CO 2 in three-dimensional heterogeneous media (layered periodic media, fluvial media and reservoir model SPE 10). (author) [fr

Phenomenology of two-dimensional stably stratified turbulence under large-scale forcing

KAUST Repository

Kumar, Abhishek; Verma, Mahendra K.; Sukhatme, Jai

2017-01-01

In this paper, we characterise the scaling of energy spectra, and the interscale transfer of energy and enstrophy, for strongly, moderately and weakly stably stratified two-dimensional (2D) turbulence, restricted in a vertical plane, under large-scale random forcing. In the strongly stratified case, a large-scale vertically sheared horizontal flow (VSHF) coexists with small scale turbulence. The VSHF consists of internal gravity waves and the turbulent flow has a kinetic energy (KE) spectrum that follows an approximate k−3 scaling with zero KE flux and a robust positive enstrophy flux. The spectrum of the turbulent potential energy (PE) also approximately follows a k−3 power-law and its flux is directed to small scales. For moderate stratification, there is no VSHF and the KE of the turbulent flow exhibits Bolgiano–Obukhov scaling that transitions from a shallow k−11/5 form at large scales, to a steeper approximate k−3 scaling at small scales. The entire range of scales shows a strong forward enstrophy flux, and interestingly, large (small) scales show an inverse (forward) KE flux. The PE flux in this regime is directed to small scales, and the PE spectrum is characterised by an approximate k−1.64 scaling. Finally, for weak stratification, KE is transferred upscale and its spectrum closely follows a k−2.5 scaling, while PE exhibits a forward transfer and its spectrum shows an approximate k−1.6 power-law. For all stratification strengths, the total energy always flows from large to small scales and almost all the spectral indicies are well explained by accounting for the scale-dependent nature of the corresponding flux.

Phenomenology of two-dimensional stably stratified turbulence under large-scale forcing

KAUST Repository

Kumar, Abhishek

2017-01-11

In this paper, we characterise the scaling of energy spectra, and the interscale transfer of energy and enstrophy, for strongly, moderately and weakly stably stratified two-dimensional (2D) turbulence, restricted in a vertical plane, under large-scale random forcing. In the strongly stratified case, a large-scale vertically sheared horizontal flow (VSHF) coexists with small scale turbulence. The VSHF consists of internal gravity waves and the turbulent flow has a kinetic energy (KE) spectrum that follows an approximate k−3 scaling with zero KE flux and a robust positive enstrophy flux. The spectrum of the turbulent potential energy (PE) also approximately follows a k−3 power-law and its flux is directed to small scales. For moderate stratification, there is no VSHF and the KE of the turbulent flow exhibits Bolgiano–Obukhov scaling that transitions from a shallow k−11/5 form at large scales, to a steeper approximate k−3 scaling at small scales. The entire range of scales shows a strong forward enstrophy flux, and interestingly, large (small) scales show an inverse (forward) KE flux. The PE flux in this regime is directed to small scales, and the PE spectrum is characterised by an approximate k−1.64 scaling. Finally, for weak stratification, KE is transferred upscale and its spectrum closely follows a k−2.5 scaling, while PE exhibits a forward transfer and its spectrum shows an approximate k−1.6 power-law. For all stratification strengths, the total energy always flows from large to small scales and almost all the spectral indicies are well explained by accounting for the scale-dependent nature of the corresponding flux.

Data splitting for artificial neural networks using SOM-based stratified sampling.

Science.gov (United States)

May, R J; Maier, H R; Dandy, G C

2010-03-01

Data splitting is an important consideration during artificial neural network (ANN) development where hold-out cross-validation is commonly employed to ensure generalization. Even for a moderate sample size, the sampling methodology used for data splitting can have a significant effect on the quality of the subsets used for training, testing and validating an ANN. Poor data splitting can result in inaccurate and highly variable model performance; however, the choice of sampling methodology is rarely given due consideration by ANN modellers. Increased confidence in the sampling is of paramount importance, since the hold-out sampling is generally performed only once during ANN development. This paper considers the variability in the quality of subsets that are obtained using different data splitting approaches. A novel approach to stratified sampling, based on Neyman sampling of the self-organizing map (SOM), is developed, with several guidelines identified for setting the SOM size and sample allocation in order to minimize the bias and variance in the datasets. Using an example ANN function approximation task, the SOM-based approach is evaluated in comparison to random sampling, DUPLEX, systematic stratified sampling, and trial-and-error sampling to minimize the statistical differences between data sets. Of these approaches, DUPLEX is found to provide benchmark performance with good model performance, with no variability. The results show that the SOM-based approach also reliably generates high-quality samples and can therefore be used with greater confidence than other approaches, especially in the case of non-uniform datasets, with the benefit of scalability to perform data splitting on large datasets. Copyright 2009 Elsevier Ltd. All rights reserved.