Inverse lift: a signature of the elasticity of complex fluids?

To understand the mechanics of a complex fluid such as a foam we propose a model experiment (a bidimensional flow around an obstacle) for which an external sollicitation is applied, and a local response is measured, simultaneously. We observe that an asymmetric obstacle (cambered airfoil profile) experiences a downards lift, opposite to the lift usually known (in a different context) in aerodynamics. Correlations of velocity, deformations and pressure fields yield a clear explanation of this inverse lift, involving the elasticity of the foam. We argue that such an inverse lift is likely common to complex fluids with elasticity.Comment: 4 pages, 4 figures, revised version, submitted to PR

Wavepacket detection with the Unruh-DeWitt model

In this paper we deal with several issues regarding the localization properties of the Unruh-DeWitt (UdW) detector model. Since its original formulation as a pointlike detector, the UdW model has been used to study extensively the physics of quantum fields in presence of accelerations or curved backgrounds. Natural extensions of it have tried to take into account the spatial profile of such detectors, but all of them have met a series of problems in their spectral response which render them useless to study some of the most interesting physical scenarios. In this paper we provide a derivation of the smeared UdW interaction from QED first principles, then we analyze the spectral response of spatially smeared UdW detectors, and discuss the kind of spatial profiles which are useful for the study of relevant cases.Comment: 7 pages, 3 figure

Ab initio study of the vapour-liquid critical point of a symmetrical binary fluid mixture

A microscopic approach to the investigation of the behaviour of a symmetrical binary fluid mixture in the vicinity of the vapour-liquid critical point is proposed. It is shown that the problem can be reduced to the calculation of the partition function of a 3D Ising model in an external field. For a square-well symmetrical binary mixture we calculate the parameters of the critical point as functions of the microscopic parameter r measuring the relative strength of interactions between the particles of dissimilar and similar species. The calculations are performed at intermediate ($\lambda=1.5$) and moderately long ($\lambda=2.0$) intermolecular potential ranges. The obtained results agree well with the ones of computer simulations.Comment: 14 pages, Latex2e, 5 eps-figures included, submitted to J.Phys:Cond.Ma

Dynamics of localized structures in vector waves

Dynamical properties of topological defects in a twodimensional complex vector field are considered. These objects naturally arise in the study of polarized transverse light waves. Dynamics is modeled by a Vector Complex Ginzburg-Landau Equation with parameter values appropriate for linearly polarized laser emission. Creation and annihilation processes, and selforganization of defects in lattice structures, are described. We find "glassy" configurations dominated by vectorial defects and a melting process associated to topological-charge unbinding.Comment: 4 pages, 5 figures included in the text. To appear in Phys. Rev. Lett. (2000). Related material at http://www.imedea.uib.es/Nonlinear and http://www.imedea.uib.es/Photonics . In this new version, Fig. 3 has been replaced by a better on

O COTIDIANO DAS FARMÁCIAS DE MANIPULAÇÃO

As farmácias de manipulação são responsáveis por uma grande alíquota do mercado de medicamentos no Brasil. Para tanto tem-se a preocupação com a qualidade das prescrições e da manipulação propriamente dita como forma de inserir o cenário real das mesmas na formação acadêmica do farmacêutico. O referido trabalho levantou as formulações de maior demanda nas farmácias de manipulação de três municípios do estado do Paraná. O resultado demonstrou que a demanda compõe-se de: cápsulas 48%, emulsões 18%, géis 3%, soluções 15%, xaropes 3%, shampoos 9% e 4% as demais (suspensões, óvulos, supositórios, soluções parenterais, comprimidos, pomadas, papéis entre outras). Levantou-se os estrangulamentos e deficiências do sistema, bem como apontou-se as vantagens da farmácia de manipulação sobre a ótica da Atenção Farmacêutica. THE ROUTINE OF MANIPULATION PHARMACIES Abstract The manipulation pharmacies are responsible for one large fraction of the pharmaceuticals market in Brazil.Consequently, there is amajor concern about the quality of prescriptions and themanipulation itself. Both aspects should be introduced in the academic studies of the pharmacist. This work raised the most demanded formulations in the manipulation pharmacies of three municipalities of Paraná State. The results demonstrated that the demand is divided in: capsules (48%), emulsions (18%), gels (5%), solutions (15%), syrups (3%), shampoos (9%) and 4% in suspensions, vaginal suppositories, suppositories, parenteral solutions, compressed tablets, ointments, and charts among others. It was also raised the major constraints and deficiencies of the system, as well as it was pointed out the advantages of manipulation pharmacies under the viewpoint of pharmaceutical care

Structural changes in intestinal enteroendocrine cells after ileal interposition in normal rats

INTRODUCTION: No therapeutic approach has significantly impacted the progression of diabetes. As early improvement of glicaemic control is observed after bariatric surgeries, there is currently a search for surgical procedures that can promote euglycemia also in non-obese patients. Glicaemic control can be achieved by increasing the blood concentration of GLP-1, a hormone produced by L cells that are more densely concentrated in the terminal ileum. The interposition of ileal segment to a more anterior region (proximal jejunum) can promote a greater stimulation of the L cells by poorly digested food, increasing the production of GLP-1 and reflecting on glicaemic control.
AIMS: To investigate long-term histological modifications of intestinal mucosa of rats submitted to interposition of ileum segment to a proximal region (jejunum).
METHODS: Forty 8-week old male Wistar-EPM1 rats (Rattus norvegicus albinus) were randomly distributed into 3 groups: the Interposition Group (IG) was subjected to ileal interposition, the Sham Group (SG) was subjected to sham operations, and the Control Group (CG) was not subjected to surgery. All animals were followed until the 60th postoperative day (8 postoperative week) when they were euthanized. Segments of jejunum and ileum from all groups were collected and analyzed by optical microscopy and immunohistochemistry.
RESULTS: No structural nor histological changes in intestinal L cells in the interposed intestinal segment and other intestinal segments were noted after ileal interposition surgery. 
CONCLUSION: As L cells endocrine characteristics were likely maintained, the use of metabolic surgical techniques for the treatment of metabolic diseases, especially diabetes, seems to be justified

A hyperbolic slicing condition adapted to Killing fields and densitized lapses

We study the properties of a modified version of the Bona-Masso family of hyperbolic slicing conditions. This modified slicing condition has two very important features: In the first place, it guarantees that if a spacetime is static or stationary, and one starts the evolution in a coordinate system in which the metric coefficients are already time independent, then they will remain time independent during the subsequent evolution, {\em i.e.} the lapse will not evolve and will therefore not drive the time lines away from the Killing direction. Second, the modified condition is naturally adapted to the use of a densitized lapse as a fundamental variable, which in turn makes it a good candidate for a dynamic slicing condition that can be used in conjunction with some recently proposed hyperbolic reformulations of the Einstein evolution equations.Comment: 11 page

Step-induced unusual magnetic properties of ultrathin Co/Cu films: ab initio study

We have performed ab initio studies to elucidate the unusual magnetic behavior recently observed in epitaxial Co films upon absorption of submonolayers of Cu and other materials. We find that a submonolayer amount of Cu on a stepped Co/Cu (100) film changes dramatically the electronic and magnetic structure of the system. The effect is mainly due to hybridization of Co and Cu $d$-electrons when copper forms a ``wire'' next to a Co step at the surface. As a result, a non-collinear arrangement of magnetic moments (switching of the easy axis) is promoted. [PACS 75.70.Ak,75.70.-i]Comment: 10 pages, RevTeX 3.0, 4 PostScript figures available on request from A. Bratkovsky at [email protected]

Galactic Collapse of Scalar Field Dark Matter

We present a scenario for galaxy formation based on the hypothesis of scalar field dark matter. We interpret galaxy formation through the collapse of a scalar field fluctuation. We find that a cosh potential for the self-interaction of the scalar field provides a reasonable scenario for galactic formation, which is in agreement with cosmological observations and phenomenological studies in galaxies.Comment: 4 pages, 3 figue