Home range evolution and its implication in population outbreaks

We investigated the phenomenon of population outbreaks in a spatial predator-prey model, and we found that pattern formation and outbreaks occur if the predators have a limited neighbourhood of interaction with the preys. The outbreaks can display a scale-invariant power-law tail, indicating self-organized criticality. We have also studied the system from an evolutionary point of view, where the predator home range is a hereditary trait subjected to mutations. We found that mutation drives the predator home range area to an optimal value where pattern formation and outbreaks are still present, but the latter are much less frequent. We developed analytical approximations using mean field and pair correlation techniques that indicate that the predation strategy is crucial for existence of this optimal home range area.     

Hydrogen production through steam electrolysis: Control strategies for a cathode-supported intermediate temperature solid oxide electrolysis cell

Hydrogen production via steam electrolysis may involve less electrical energy consumption than conventional low temperature water electrolysis, reflecting the favourable thermodynamics and kinetics at elevated temperatures. The present paper reports on the development of a one-dimensional dynamic model of a cathode-supported planar intermediate temperature solid oxide electrolysis cell (SOEC) stack with air flow introduced through the cells. The model, which consists of an electrochemical model, two mass balances, and four energy balances, is here employed to study the prospect of the stack temperature control through the variation of the air flow rate. The simulations found that the increase in the air flow rate provides enhanced cooling and heating during exothermic and endothermic operations, respectively. The stack behaviour has suggested that such a convective heat transfer between the cell components and air flow would allow the control of stack temperature. However, only a small dependence of the temperature on the air flow rate was observed for a stack driven at conditions near thermoneutral operation, indicating that this operating mode should be avoided from a control perspective.     

Essais d’adhérence des époxydes au béton hydraulique (Tests on bonding between epoxies and hydraulic concrete)

Summary The importance of techniques of repair and glued assembly of concrete structures is becoming increasingly obvious. The need to repair these structures arises from their age or construction defects. Polymers are now being used in glued assembly and repairs because of their adhesion quality which ensures bonding of hardened concrete-hardened concrete, hardened concrete-fresh concrete and hardened concrete-metallic materials. This article presents two tests, one under direct tension and the other based on the priciples of fracture mechanics. The latter offers the possibility of a more rigorous evaluation of the bond than direct tension tests. The author has determined the tensile strength and the energy recovery rate for the bond between hardened concrete and epoxy.

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Résumé La réparation et les collages de structures en béton sont des travaux dont l’utilité se fait de plus en plus sentir. La nécessité de réparer ces structures provient de leur ancienneté ou de défauts de construction. Les polymères sont toujours davantage utilisés dans les travaux de réparation et de collage en raison de leur capacité d’adhérence qui rend possible la liaison béton durci-béton durci, béton durci-béton frais et béton durci-matériaux métalliques par collage. Nous présentons deux essais, l’un de traction direct et l’autre basé sur les principes de la mécanique de la rupture. Ce dernier nous a permis d’évaluer l’adhérence de fa?on plus rigoureuse que les essais de traction directe. Nous avons déterminé la résistance à la traction et les taux de restitution d’énergie pour l’adhérence entre béton durci et époxyde.

     

Survival after aorto-femoral shunt with Dacron prosthesis

The purpose of this paper is to establish the survival rate of patients submitted to aorto-femoral bypass grafting and compare it with the general mortality rate of the population in the State of S?o Paulo. The records of 210 patients with aorto-femoral bypass grafts and mean age of 54 years were analysed according the Kaplan and Meyer method. The survival curves of the normal population with the age of 55 and 70 years were used for comparison. Our results are comparable with those reported in the international literature. The aorto-femoral atherosclerotic disease Hás the same features wherever lives the patient. The death is caused mainly by cardiac disease. In our patients, however, the infection of the prosthesis was also an important factor in the fatal outcome of the disease. After ten years about half of the patients submitted to an aorto-femoral bypass grafting are still alive.     

Peach palm (Bactris gasipaes H.B.K.), a new source of vegetable oil from the wet tropics

Fruit bunches of Bactris gasipaes have been analysed in an attempt to select for high oil content. Bunches varied in weight from 1.4 to 19 kg, of which 86–96.8% was fruit. They held 8–420 fruit of 6.7–244.4 g. Fruit size varied from 1 to 9 cm in diameter, and contained 3.8–225.1 g of mesocarp. The latter, together with the thin exocarp, represented 73.4–98.4% of the fruit weight in seeded fruit. This pulp contained 17.8–74.8% dry matter which consisted of 3.1–14.7% protein, 2.2–61.7% oil, 14.5–84.8% starchy N-free extract, and 5.2–13.8% fibre. Some mesocarps also had very high levels of carotene (0–70 mg 100g^?1 fresh weight) and oxalate-like crystals were frequently found, especially in and just under the exocarp. Oil contents increased with fruit maturity and also varied a little with bunch and season. The best introduction could produce 34.3% oil per bunch plus 21.3% of a dry meal containing 22.6% protein and 35.8% fibre, plus 4.3% dry kernels containing 21% oil. This very high oil content is well above previous results and suggests that the species might become a useful alternative oil source in the wet tropics, once the character is combined with high field yields. In addition, the oil residue could be used as animal feed or even for human consumption, especially after separating out large fibre particles.     

A modified Runge-Kutta method with phase-lag of order infinity for the numerical solution of the Schrödinger equation and related problems

A modified Runge-Kutta method with phase-lag of order infinity for the numerical solution of the Schr?dinger equation and related problems is developed in this paper. This new modified method is based on the classical Runge-Kutta method of algebraic order four. The numerical results indicate that this new method is more efficient for the numerical solution of the Schr?dinger equation and related problems than the well known classical Runge-Kutta method of algebraic order four.     

The role of official heritage in regional spaces

Following the argument that increasing mobility has scattered consumption throughout Sweden’s regions, this study investigates how individuals’ consumption choices are influenced by official heritage. It argues that individuals’ everyday routines highlight the role played by heritage in socio-economic regional change, challenging traditional planning systems and altering individuals’ relationships with their environments, leading to new values being placed on official heritage. This argument was tested using interviews and questionnaires in Mariefred, Sweden, and demonstrates that official heritage plays multiple and contrasting roles, including the use of heritage as an attempt to reconcile opposing principles such as progress/development and tradition/conservation.