Leaf-cutting ant faecal fluid and mandibular gland secretion: effects on microfungi spore germination

The mandibular gland secretion (MGS) and the faecal fluid (FF) of the leaf-cutting ant Atta sexdens rubropilosa Forel affected the spore germination of selected microfungi isolated from nests of this insect. MGS was more effective than the FF, completely inhibiting the spore germination of four out of six microfungi species.

Influence of Fluid Concentration on the Elevation of Boiling Point of Blackberry Juice

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A mass-transportation approach to a one dimensional fluid mechanics model with nonlocal velocity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Limits of validity for a semiclassical mean-field two-fluid model for Bose-Einstein condensation thermodynamics

We reinvestigate the Bose-Einstein condensation (BEC) thermodynamics of a weakly interacting dilute Bose gas under the action of a trap using a semi-classical two-fluid mean-field model in order to find the domain of applicability of the model. Such a model is expected to break down once the condition of diluteness and weak interaction is violated. We find that this breakdown happens for values of coupling and density near the present experimental scenario of BEG. With the increase of the interaction coupling and density the model may lead to unphysical results for thermodynamic observables. (C) 2000 Published by Elsevier B.V. B.V, All rights reserved.

An exact equation for the free surface of a fluid in a porous medium

We study the problem of the evolution of the free surface of a fluid in a saturated porous medium, bounded from below by a. at impermeable bottom, and described by the Laplace equation with moving-boundary conditions. By making use of a convenient conformal transformation, we show that the solution to this problem is equivalent to the solution of the Laplace equation on a fixed domain, with new variable coefficients, the boundary conditions. We use a kernel of the Laplace equation which allows us to write the Dirichlet-to-Neumann operator, and in this way we are able to find an exact differential-integral equation for the evolution of the free surface in one space dimension. Although not amenable to direct analytical solutions, this equation turns out to allow an easy numerical implementation. We give an explicit illustrative case at the end of the article.

Solitary waves on a free surface of a heated Maxwell fluid

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Universal scaling in a trapped Fermi super-fluid in the BCS-unitarity crossover

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PRODUCTION of THERMAL PHOTONS IN VISCOUS FLUID DYNAMICS WITH TEMPERATURE-DEPENDENT SHEAR VISCOSITY

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

BCS-BEC crossover in a trapped Fermi super-fluid using a density-functional equation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Shear viscosity from thermal fluctuations in relativistic conformal fluid dynamics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Noncommutative fluid dynamics in the Snyder space-time

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Accelerating solutions of perfect fluid hydrodynamics for initial energy density and life-time measurements in heavy ion collisions

A new class of accelerating, exact, explicit and simple solutions of relativistic hydrodynamics is presented. Since these new solutions yield a finite rapidity distribution, they lead to an advanced estimate of the initial energy density and life-time of high energy heavy ion collisions. Accelerating solutions are also given for spherical expansions in arbitrary number of spatial dimensions.

Fluid dynamics of air in a packed bed: velocity profiles and the continuum model assumption

Air flow through packed beds was analyzed experimentally under conditions ranging from those that reinforce the effect of the wall on the void fraction to those that minimize it. The packing was spherical particles, with a tube-to-particle diameter ratio (D/dp) between 3 and 60. Air flow rates were maintained between 1.3 and 4.44 m3/min, and gas velocity was measured with a Pitot tube positioned above the bed exit. Measurements were made at various radial and angular coordinate values, allowing the distribution of air flow across the bed to be described in detail. Comparison of the experimentally observed radial profiles with those derived from published equations revealed that at high D/dp ratios the measured and calculated velocity profiles behaved similarly. At low ratios, oscillations in the velocity profiles agreed with those in the voidage profiles, signifying that treating the porous medium as a continuum medium is questionable in these cases.

Endocrine profiles and ovulation rate of cows superovulated with FSH following passive immunization against steroid free-bovine follicular fluid

Dez vacas multíparas, secas, foram distribuídas aleatoriamente em dois grupos de cinco animais cada. Nos dias 8 a 12 do diestro, o primeiro grupo recebeu 100 ml de anti-soro contra líquido folicular livre de esteróides (anti-LFb) produzido em ovelhas ovariectomizadas. O segundo grupo (controle) recebeu 100 ml de soro de ovelhas não-imunizadas. Seis horas após a aplicação, os dois grupos foram superovulados com FSH (18 NIH-FSH-S1 unidades) e LH (0,29 NIH-LH-S1 unidades) administrados em quantidades decrescentes durante quatro dias. Na manhã do terceiro dia, foi administrada uma dose luteolítica de cloprostenol. Duas inseminações foram realizadas 48 e 60 horas após. Os embriões foram recuperados pelo método cervical 7 dias após a primeira inseminação. Amostras de sangue foram coletadas durante todo o período experimental para determinar, por radioimunoensaio, as concentrações plasmáticas de FSH, LH e progesterona. Todas as vacas do grupo imunizado e 3 do grupo controle apresentaram mais de 2 CL. Não existiu diferença significativa (P>0,05) na taxa de ovulação entre os grupos imunizado e controle (14,4 e 9,9, respectivamente). O número de embriões recuperado não foi significativamente diferente (P>0,05) entre os grupos, embora o grupo imunizado tenha apresentado maior número de embriões transferíveis (3,4 ± 1,0 versus 0,8 ± 0,4, P<0,05). As concentrações de gonadotrofinas plasmáticas não foram correlacionadas com a taxa de ovulação ou com o número de embriões recuperados. As concentrações de progesterona plasmática foram positivamente correlacionadas (r = 0,88, P<0,01) com a taxa de ovulação. Os resultados sugerem que o anti-LFb, aplicado antes da superovulação, não reduz a variabilidade da resposta ovariana.

Agarose gel electrophoresis of cerebrospinal fluid proteins of dogs after sample concentration using a membrane microconcentrator technique

Background: Cerebrospinal fluid (CSF) is produced in the cerebral ventricles through ultrafiltration of plasma and active transport mechanisms. Evaluation of proteins in CSF may provide important information about the production of immunoglobulins within the central nervous system as well as possible disturbances in the blood-brain barrier. Objective: the objective of this study was to measure the concentration and fractions of protein in CSF samples using a membrane microconcentrator technique followed by electrophoresis, and to compare the protein fractions obtained with those in serum. Methods: CSF samples from 3 healthy dogs and 3 dogs with canine distemper virus infection were concentrated using a membrane microconcentrator having a 0.5 to 30,000 d nominal molecular weight limit (Ultrafree, Millipore, Billerica, MA, USA). Protein concentration was determined before and after concentration. Agarose gel electrophoresis was done on concentrated CSF samples, serum, and serial dilutions of one of the CSF samples. Results: Electrophoretic bands were clearly identified in densitometer tracings in CSF samples with protein concentrations as low as 1.3 g/dL. The higher CSF protein concentration in dogs with distemper was mainly the result of increased albumin concentration. Conclusion: the microconcentrating method used in this study enables characterization of the main protein fractions in CSF by routine electrophoresis and may be useful for interpreting the underlying cause of changes in CSF protein concentrations