Putnam’s argument aims to prove that future is as real as present. His argument is based on the equation present = real. Is real what exists now. Is real what is part of observer-independent reality. What exists now depends on an observer—it is not real. It is then shown that Special Relativity is not only a physical theory, it has also a philosophical dimension in that it questions our very understanding of reality and requires a clear distinction between reality and (...) its representation. (shrink)

The Measurement problem and Non-locality are classical problems in Quantum Mechanics and still unsolved in spite of the many proposed solutions. A new interpretation is proposed here, based on the idea that they are closely related problems. But it requires that we consider space and time not as objective mediums but as features of our representation of reality, as Kant explained more than two centuries ago.

Modelling of contagious disease usually employs compartmental SEIR-like models where the waiting times in respective compartments are exponentially distributed. In this paper, we are interested in investigating how the distributions of sojourn times in infective compartments affect the dynamics and persistence of the contagious bovine pleuropneumonia, a chronic respiratory disease of cattle. Two kinds of extreme distributions of the sojourn times are considered: a Dirac delta-function and truncated Gaussian function leading to a model with (non-constant) delay and the classical exponential (...) distribution that stands for a model without delay. Expressions of the basic reproductive numbers are derived and dynamical behaviours are discussed for the three models. It is found that the spreading of disease exhibits wave-like oscillations for the time-delay dynamics. In contrast, the disease appears to last longer when the spreading is described by the classical dynamics without delay. Subsequently, the time-delay dynamics turns out to be more appropriate for the description of an experimental epidemic of CBPP. (shrink)

A compartmental model is described for the spread of Gambian sleeping sickness in a spatially heterogeneous environment in which vector and human populations migrate between two "patches": the village and the plantations. The number of equilibrium points depends on two "summary parameters": gr the proportion removed among human infectives, and R0, the basic reproduction number. The origin is stable for R0 1. Control strategies are assessed by studying the mix of vector control between the two patches that bring R0 below (...) 1. The results demonstrate the importance of vector control in the plantations. For example if 20 percent of flies are in the village and the blood meal rate in the village is 10 percent, then a 20 percent added vector mortality in the village must be combined with a 9 percent added mortality in the plantations in order to bring R0 below 1. The results are quite insentive to the blood meal rate in the village. Optimal strategies (that minimize the total number of flies trapped in both patches) are briefly discussed. (shrink)

Physical reality is always in a unique state, and its presence has no duration. Motion, as passing from one state of reality to another, requires at least two states. If physical reality is always in a unique state, there is no movement in it. For motion to exist, there must then be another dimension of reality—where unicity is replaced by plurality, i.e., by its negation—by an observer-created non-physical reality, an abstract representation of reality, where past states remain present and motion (...) is possible. Motion then requires retaining the past, and retaining the past is possible only in the observer’s representation of reality—in what Kant called phenomenal reality. (shrink)