Paul Sabatier University

About: Paul Sabatier University is a education organization based out in Toulouse, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 15431 authors who have published 23386 publications receiving 858364 citations.

Routing in telecommunications networks with ant-like agents

Abstract: A simple mechanism is presented, based on ant-like agents, for routing and load balancing in telecommunications networks, following the initial works of Appleby and Stewart [1] and Schoonderwoerd et al. [32,33]. In the present work, agents are very similar to those proposed by Schoonderwoerd et al. [32,33], but are supplemented with the ability to perform more computations at switching nodes, which significantly improves the network's relaxation and its response to perturbations.

Thermotropic liquid crystalline glycolipids

Abstract: Are the liquid crystalline properties of the materials of living systems important in biological structures, functions, diseases and treatments? There is a growing consciousness that the observed lyotropic, and often thermotropic liquid crystallinity, of many biological materials that possess key biological functionality might be more than curious coincidence. Rather, as the survival of living systems depends on the flexibility and reformability of structures, it seems more likely that it is the combination of softness and structure of the liquid-crystalline state that determines the functionality of biological materials. The richest sources of liquid crystals derived from living systems are found in cell membranes, of these glycolipids are a particularly important class of components. In this critical review, we will examine the relationship between chemical structure and the self-assembling and self-organising properties of glycolipids that ultimately lead to mesophase formation.

Periodontitis induced by Porphyromonas gingivalis drives periodontal microbiota dysbiosis and insulin resistance via an impaired adaptive immune response

Abstract: Objective To identify a causal mechanism responsible for the enhancement of insulin resistance and hyperglycaemia following periodontitis in mice fed a fat-enriched diet. Design We set-up a unique animal model of periodontitis in C57Bl/6 female mice by infecting the periodontal tissue with specific and alive pathogens like Porphyromonas gingivalis ( Pg ), Fusobacterium nucleatum and Prevotella intermedia . The mice were then fed with a diabetogenic/non-obesogenic fat-enriched diet for up to 3 months. Alveolar bone loss, periodontal microbiota dysbiosis and features of glucose metabolism were quantified. Eventually, adoptive transfer of cervical (regional) and systemic immune cells was performed to demonstrate the causal role of the cervical immune system. Results Periodontitis induced a periodontal microbiota dysbiosis without mainly affecting gut microbiota. The disease concomitantly impacted on the regional and systemic immune response impairing glucose metabolism. The transfer of cervical lymph-node cells from infected mice to naive recipients guarded against periodontitis-aggravated metabolic disease. A treatment with inactivated Pg prior to the periodontal infection induced specific antibodies against Pg and protected the mouse from periodontitis-induced dysmetabolism. Finally, a 1-month subcutaneous chronic infusion of low rates of lipopolysaccharides from Pg mimicked the impact of periodontitis on immune and metabolic parameters. Conclusions We identified that insulin resistance in the high-fat fed mouse is enhanced by pathogen-induced periodontitis. This is caused by an adaptive immune response specifically directed against pathogens and associated with a periodontal dysbiosis.

How do king penguins (Aptenodytes patagonicus apply the mathematical theory of information to communicate in windy conditions

Abstract: In the king penguin ( Aptenodytes patagonicus ), both pair members alternate in incubating and rearing their chick. Mates can recognize each other among thousands of other birds in the hubbub of the colony using only acoustic signalling: the display call. Large penguin colonies are found on sub–Antarctic islands where strong winds blow throughout the year. We have shown by experiments under natural conditions that the level of background noise increases in windy conditions and thus leads to a diminution of the signal–to–noise ratio. Moreover the emergence level of the signal revealed by entropy calculation is statistically weaker in windy conditions. To achieve breeding success, birds must continue communicating in spite of the significant decrease in the total amount of information that can be transmitted in windy situations. For the first time, to our knowledge, we have shown that a bird species takes into account the constraints imposed by wind on their acoustic communication. In windy conditions, birds try to maintain the efficiency of communication by increasing both the number of calls emitted and the number of syllables per call. This result conforms with predictions from the mathematical theory of communication: increased redundancy in a signal improves the probability of receiving a message in a noisy channel.