Activity of Cuban propolis extracts on Leishmania amazonensis and Trichomonas vaginalis

In this paper we analyzed the antiprotozoal effects of eighteen Cuban propolis extracts (brown, red and yellow type) collected in different geographic areas, using Leishmania amazonensis (as a model of intracellular protozoa) and Trichomonas vaginalis (as a model of extracellular protozoa). All evaluated propolis extracts caused inhibitory effect on intracellular amastigotes of L. amazonensis. However, cytotoxicity on peritoneal macrophages from BALB/c mice was observed. Only five samples decreased the viability of T. vaginalis trophozoites at concentrations lower than 10 microg/mL. No correlation between the type of propolis and antiprotozoal activity was found. Cuban propolis extracts demonstrated activity against both intracellular and extracellular protozoa model, as well as the potentialities of propolis as a natural source to obtain new antiprotozoal agents.     

On the spatial behavior of solutions for non-linear type II heat conduction

In this paper we study the spatial behavior of the solutions for a problem determined by the non-linear version of the Green and Naghdi type II heat conduction theory. We obtain a spatial decay estimates for the usual boundary-initial-value problem and also an upper bound for the amplitude term of the spatial estimate. Finally, we analyze a non-standard initial value problem defined on a particular family of heat conductors.     

A Model of Joined Beams as Limit of a 2<Emphasis Type="Italic">D</Emphasis> Plate

In this paper, we consider an elastic multi-structure composed of two joined beams forming an angle \(\alpha\in \, ]0,\frac{\pi}{2}]\) at the junction, clamped at the three extremities and submitted to forces transverse to the plane containing the skeleton of the multi-structure. We derive the equilibrium configuration of the transverse displacement and the torsional rotation of the multi-structure, via an asymptotic analysis based on a dimensional reduction of a Kirchhoff-Love plate. More generally, we obtain the equilibrium configuration of the transverse displacement and the torsional rotation of a multi-structure whose skeleton is composed of a line and a planar curve joined together.     

Structure of saddle-node and cusp bifurcations of periodic orbits near a non-transversal T-point

Non-transversal T-points have been recently found in problems from many different fields: electronic circuits, pendula, and laser problems. In this work, we study a model based on the construction of a Poincaré map that describes the behaviour of curves of saddle-node and cusp bifurcations in the vicinity of such a non-transversal T-point. This model is also able to predict, reproduce, and explain the numerical results previously obtained in Chua’s equation.     

Probing the nature of the contact between fine particles by using ultrasound propagation

The propagation velocity (vs) of an ultrasonic signal through a granular material depends on the type of interparticle contact. For noncohesive glass beads, a power law behavior for consolidation stresses applied (σc) above 1 MPa has been measured in previous work. This equation is compatible with Hertz's interaction law between elastic solids. In the present work, we have tested the propagation velocity of ultrasound signals through a sample of fine powder. The tensile strength and compactivity of the powder were previously measured by means of the Seville powder tester (SPT), indicating plastic deformation of the surface asperities in contact for small to moderate consolidation stresses. However, the measurements of ultrasound propagation at high consolidations presented here are compatible with Hertz's law. This finding suggests that for high consolidation stresses, surface asperities are flattened, and it is therefore the elastic deformation of the bulk of the particles that determines the transmission of ultrasonic pulses.     

Selecting intervention strategies against eutrophication and the drastic decrease in bird abundance in Ringkøbing Fjord

Ringkøbing Fjord is a large and shallow brackish lagoon on the west coast of Denmark that has gone through two environmental regime shifts in recent decades. Different intervention strategies, including nutrient abatement and the construction of facilities to increase the water exchange between the lagoon and the outside sea, have been proposed to achieve good water quality in terms of trophic state and conditions for waterfowl. The selection of an intervention strategy is a complex decision-making problem in which several conflicting objectives, like costs of application and environmental or social impacts, must be taken into account simultaneously. We propose a PC-based decision support system, called the Generic Multi-Attribute Analysis system, to deal with such interdisciplinary analyses. It evaluates the intervention strategies by means of an additive multiattribute utility model accounting for imprecision of the various components of the analysis, such as intervention strategy performances and decision-makers’ preferences. Also, it implements what is known as decision making with partial information, through the application of Monte Carlo simulation techniques. This enables a straightforward analysis of the difference between an anthropocentrist and an ecocentrist view of the problem, from which a final recommendation can be reached.     

Spacelike Surfaces in {{\mathbb L}^4} with Degenerate Gauss Map

In this paper we study and present a complete classification of spacelike surfaces with degenerate Gauss map in the Lorentz?CMinkowski space ${\mathbb L^4}$ .     

Mixed integer linear models for the optimization of dynamical transport networks

We introduce a mixed integer linear modeling approach for the optimization of dynamic transport networks based on the piecewise linearization of nonlinear constraints and we show how to apply this method by two examples, transient gas and water supply network optimization. We state the mixed integer linear programs for both cases and provide numerical evidence for their suitability.     

Number of infections suffered by a focal individual in a two‐strain SIS model with partial cross‐immunity

We study a stochastic model for the spread of two pathogen strains—termed type 1 and type 2—among a homogeneously mixing community consisting of a finite number of individuals. In the model, we assume partial cross‐immunity, exogenous streams of infection, and that the degree of severity of a newly infective individual depends on who this infective individual was infected by. The aim is to characterize the joint probability distribution of the numbers M₁ and M₂ of type‐1 and type‐2 infections suffered by a focal individual during an outbreak of the disease. We present iterative procedures for computing the probability mass function of (M₁,M₂) under the assumption that the initial state of the focal individual is known, and a numerical study of the model is performed to investigate the influence of certain key parameters on the spread of resistant bacteria in hospitals.     

Piecewise linear processes with Poisson‐modulated exponential switching times

We consider the jump telegraph process when switching intensities depend on external shocks also accompanying with jumps. The incomplete financial market model based on this process is studied. The Esscher transform, which changes only unobservable parameters, is considered in detail. The financial market model based on this transform can price switching risks as well as jump risks of the model.