Constant-length substitutions and countable scrambled sets

In this paper we provide examples of topological dynamical systems having either finite or countable scrambled sets. In particular we study conditions for the existence of Li-Yorke, asymptotic and distal pairs in constant--length substitution dynamical systems. Starting from a circle rotation we also construct a dynamical system having Li--Yorke pairs, none of which is recurrent

Naledi : an example of how natural phenomena can inspire metaphysical assumptions

Abstract: A new fossil site was discovered in the Rising Star Cave in 2013 in the Cradle of Humankind in South Africa. This site which has yielded 1550 hominin bones so far is considered to be one of the richest palaeoanthropological sites in the world. The deposition of the fossils in a remote part of the cave system, approximately 100 m from the entrance, has resulted in a great deal of speculation. The relative inaccessibility of the site and the number of fossil bones it contained and the fact that virtually all these bones were those of a single species of hominid led to the conclusion that the bones were not deposited because of natural sedimentary processes, but that these phenomena were evidence of purposeful disposal or even burial of the dead by hominins. If this assumption is true, it would be the earliest evidence of a metaphysical awareness in humankind. The tenuous evidence on which this hypothesis rests will be discussed and a more plausible alternative explanation where water and gravity were responsible for the deposition of the remains is forwarded

A propos de la géographie de l'eau : temporalités et échelles spatiales

Questions about the geography of water are raised here only as a case study of combinations of components of different nature and different levels of scale, concerning time and space. A description of stocks and flows leads to the interactions between several main uses of water, set in a systemic framework. The inputs of the system are then taken into account, from the point of view of their nature and hierarchical structure. Their combination leads to a definition of types of "water spaces", which are used to classify human actions on the geography of water. These actions are defined as means to "correct" for the benefits of mankind, the natural spatial and temporal distributions of water. Spatial and temporal "corrections" of different levels of size and efficiency are combined in the main technics used for the management of water ressources.Les problèmes de l'eau dans le monde sont envisagés ici seulement dans le cadre d'une étude de cas des interactions entre des composantes spatiales et temporelles différant aussi bien par leur niveau scalaire que par leur nature. La définition et la quantification des stocks et des flux d'eau, permet d'établir les interactions entre les usages principaux qui sont faits de l'eau et de formaliser ces interactions sous forme d'un système. Les entrées de ce système de base sont ensuite prises en considérations, et étudiées du point de vue de leurs niveaux hiérarchiques et de leur nature. Leur combinaison permet de définir des "espaces de l'eau" qui servent de cadre pour classer les types d'action des sociétés humaines en matière de géographie de l'eau. Ces actions sont définies comme des "corrections", au bénéfice des hommes, des répartitions naturelles dans le temps et dans l'espace. Corrections spatiales et temporelles d'ampleur et d'efficacité variées se combinent dans les techniques les plus importantes, qui sont donc situées les unes par rapport aux autre

L'Inde dans la mondialisation

The changes that took place in India since the 1990ies are shown as a part of a long term evolution, which led to the entry of India in the world economy, following a specific sequence. Similarly, the forms of India's integration in global net works are also specific. In spite of the new power position acquired by India, resistance to globalisation is present in a rather great variety of forms.Les changements qui ont eu lieu en Inde à partir des années 1990 sont inscrits dans une perspective d'évolution à long terme, qui a conduit à l'entrée de l'Inde dans la mondialisation selon une séquence originale, comme sont originales les formes d'intégration de l'Inde dans les réseaux mondiaux.Les résistances à la mondialisation ne manquent pas en Inde,malgré la puissance qu'elle acquiert dans un grand nombre de domaines

Hydrothermal synthesis of nanosized BaTiO3 powders and dielectric properties of corresponding ceramics

BaTiO3 fine powders were synthesized by hydrothermal method at 150 °C or 250 °C for 7 h, starting from a mixture of TiCl3 + BaCl2 or TiO2 + BaCl2. The size of the crystallites is close to 20 nm whatever the starting mixture and the reaction temperature. These powders are well crystallized and constituted of a mixture of the metastable cubic and stable tetragonal phases. The ceramics obtained after uniaxial pressing and sintering at 1250 °C for 10 h or 20 h present high densification (up to 99.8%). The Curie temperature (Tc) and the electrical permittivity ( r) of the ceramics strongly depend on the type of titanium source that has been used for preparing the powder and on the sintering dwell time. Particularly, Tc is shifted towards lower temperature when TiCl3 is used. The permittivity value at Tc of BaTiO3 sintered at 1250 °C for 10 h reaches 7000 and 11,000 with respectively TiCl3 and TiO2 used as titanium source

Modeling tree architecture and forest dynamics. A research project in the dense moist evergreen forests of the Western Ghats (South India)

This working paper presents a research programme which aims at modelling the dynamics of the dense moist evergreen forests of the Western Ghats (India) from analysing, modelling and simulating tree architecture. The paper first reviews various approaches to modelling the dynamics of heterogeneous forests, either temperate or tropical: demographic matrix models, distance-dependent tree growth models, gap models, cellular automata and multiagent systems. The advantages and drawbacks of the architectural approach are then discussed. The proposed study site is then briefly presented and a programme is outlined: selection of some species which are both frequent and representative of the different forest strata, sampling strategy and measurements, methods used for modelling and computer simulation. The preliminary results obtained since the project was started in early 1995 are then briefly reviewed; a more detailed account will soon be published in another paper of this series

Aggregating Correlated Estimations with (Almost) no Training

Many decision problems cannot be solved exactly and use several estimation algorithms that assign scores to the different available options. The estimation errors can have various correlations, from low (e.g. between two very different approaches) to high (e.g. when using a given algorithm with different hyperparameters). Most aggregation rules would suffer from this diversity of correlations. In this article, we propose different aggregation rules that take correlations into account, and we compare them to naive rules in various experiments based on synthetic data. Our results show that when sufficient information is known about the correlations between errors, a maximum likelihood aggregation should be preferred. Otherwise, typically with limited training data, we recommend a method that we call Embedded Voting (EV)