Low-Prandtl-number B\'enard-Marangoni convection in a vertical magnetic field

The effect of a homogeneous magnetic field on surface-tension-driven B\'{e}nard convection is studied by means of direct numerical simulations. The flow is computed in a rectangular domain with periodic horizontal boundary conditions and the free-slip condition on the bottom wall using a pseudospectral Fourier-Chebyshev discretization. Deformations of the free surface are neglected. Two- and three-dimensional flows are computed for either vanishing or small Prandtl number, which are typical of liquid metals. The main focus of the paper is on a qualitative comparison of the flow states with the non-magnetic case, and on the effects associated with the possible near-cancellation of the nonlinear and pressure terms in the momentum equations for two-dimensional rolls. In the three-dimensional case, the transition from a stationary hexagonal pattern at the onset of convection to three-dimensional time-dependent convection is explored by a series of simulations at zero Prandtl number.Comment: 26 pages, 9 figure

Pearling and Pinching: Propagation of Rayleigh Instabilities

A new category of front propagation problems is proposed in which a spreading instability evolves through a singular configuration before saturating. We examine the nature of this front for the viscous Rayleigh instability of a column of one fluid immersed in another, using the marginal stability criterion to estimate the front velocity, front width, and the selected wavelength in terms of the surface tension and viscosity contrast. Experiments are suggested on systems that may display this phenomenon, including droplets elongated in extensional flows, capillary bridges, liquid crystal tethers, and viscoelastic fluids. The related problem of propagation in Rayleigh-like systems that do not fission is also considered.Comment: Revtex, 7 pages, 4 ps figs, PR

Measurement of the reaction gamma*p->phi p in deep, inelastic e(+)p scattering at HERA

The production of phi mesons in the reaction e(+)p --> e(+)phi p (phi --> K+K-), for 7 phi p cross section rises strongly with W. This behaviour is similar to that previously found for the gamma*p --> rho(0)p cross section. This strong dependence cannot be explained by production through soft pomeron exchange, It is, however, consistent with perturbative QCD expectations, where it reflects the rise of the gluon momentum density in the proton at small x. The ratio of sigma(phi)/sigma(rho(0)), which has previously been determined by ZEUS to be 0.065 +/- 0.013 (stat.) in photoproduction at a mean W of 70 GeV, is measured to be 0.18 +/- 0.05 (stat.) +/- 0.03 (syst.) at a mean Q(2) of 12.3 GeV2 and mean W of approximate to 100 GeV and is thus approaching at large Q(2) the value of 2/9 predicted from the quark charges of the vector mesons and a flavour independent production mechanism

Medical image of the week: leukemic infiltrates

No abstract available. Article truncated after 150 words. A 50 year-old white man with newly diagnosed, acute T-cell prolymphocytic leukemia presented with progressive exertional dyspnea and non-productive cough. The patient was due to meet with his hematologist that day to discuss initiation of treatment. The patient had not noted fever, chills, night sweats, chest pain, or lower extremity swelling. Blood pressure was 112/60 mm Hg, respiratory rate was 36/minute and labored, pulse was 110/minute and temperature was 37 degrees Celsius. Oxygen saturation measured by pulse oximetry was 62% on room air at rest, and rose to 90% after the application of a 100% non-rebreather mask. Diffuse rales were present on chest auscultation. Marked splenomegaly was present on abdominal examination. Peripheral white blood count was 112.2 K/ul with 99% lymphocytes. Smudge cells were noted. Hemoglobin was 12.9 g/dl and platelet count was 93K/ul. Procalcitonin level was 0.3 pg/ml. The chest radiograph demonstrated diffuse bilateral infiltrates (Figure 1). The patient ..

Osteoarthritis and Osteoporosis

Book Summary: Serves the needs of advanced practice nurses because it’s written by nurse practitioners for nurse practitioners, in collaboration with a physician. Organizes content around the Circle of Caring framework for nursing-based knowledge and holistic care. Explores complementary and alternative treatments for each disorder. Covers the broadest range of human disease and disorders using a systems-based approach, presenting both common complaints and common problems to help students narrow down the possible differentials to the most likely diagnosis. Considers interactions of pharmaceuticals with alternative medications and nutraceuticals. Features coverage of pathophysiology and diagnostic reasoning as well as up-to-date guidance on laboratory and diagnostic tests. Emphasizes evidence-based practice with information on evidence levels and more references to primary studies. Integrates discussions of health policy and primary care throughout the text

Common Musculoskeletal Complaints

Book Summary: Serves the needs of advanced practice nurses because it’s written by nurse practitioners for nurse practitioners, in collaboration with a physician. Organizes content around the Circle of Caring framework for nursing-based knowledge and holistic care. Explores complementary and alternative treatments for each disorder. Covers the broadest range of human disease and disorders using a systems-based approach, presenting both common complaints and common problems to help students narrow down the possible differentials to the most likely diagnosis. Considers interactions of pharmaceuticals with alternative medications and nutraceuticals. Features coverage of pathophysiology and diagnostic reasoning as well as up-to-date guidance on laboratory and diagnostic tests. Emphasizes evidence-based practice with information on evidence levels and more references to primary studies. Integrates discussions of health policy and primary care throughout the text