The effects of airline alliances: What do the aggregate data say?

We consider an empirical model of worldwide airline alliances that we apply to a large set of companies for the period 1995-2000. Using observations at the network level, we estimate a cost, capacity, and demand system that accounts for cross-price elasticities. Our contribution consists in evaluating airlines' strategical interactions through the window of firms' network interconnections. We consider networks coincidences and potential connections with all their rivals. The results allow us to classify all company pairs as either complements or substitutes. We shed light on the fact that many airlines involved in the same alliance are potential substitutes.

Regulation and Incentives in European Aviation

We study the effect of liberalization on costs and competition in the European airline industry. We construct and estimate a model that includes demand, capacity, and cost equations. The latter accounts for inefficiency and cost-reducing effort. We show that failure to account for the choice of effort would lead to biased estimates of efficiency and competition in the industry. We also find that the last European Union package of deregulatory measures has led to significant efficiency improvements and has fostered competition.

OUTIL EVOLUTIONNAIRE D'AIDE A LA CONCEPTION ARCHITECTURALE CREATIVE.: Mise en oeuvre d'un algorithme génétique et prise en compte des paramètres environnementaux.

International audienceThis work focuses on the development of a tool capable of assisting and supporting architectural design activity. We propose an evolutionary mechanism through the use of a genetic algorithm. Environmental parameters are convoked to drive the evolution. The solar passive qualities of the object under study allow the energizing evaluation. This paper deals with the interaction between verbal thinking and visual thinking through the use of this generative tool.Cette recherche porte sur le développement d'un outil d'assistance à la conception architecturale. L'outil évolutionnaire que nous proposons utilise un algorithme génétique et convoque les paramètres environnementaux pour conduire l'évolution. Ce sont les qualités solaires passives de l'objet en cours d'étude qui serviront d'évaluation énergétique. Notre propos porte ici sur l'identification des intéractions existantes entre la pensée verbale et la pensée visuelle à travers l'utilisation de cet outil génératif

Generative exploration of architectural envelope responding to solar passive qualities.

International audienceThis paper deals with the architectural design process and the digital tools able to support a creative activity. Evolutionary devices are expected to support the architect in the initial phase of his work in progress and to stimulate his creativity through analogical thinking. An experimental tool is described, this one is using a genetic algorithm to explore the solution space, and it is based on both solar passive qualities and subjective interaction

The food contaminant deoxynivalenol, decreases intestinal barrier permeability and reduces claudin expression

The gastrointestinal tract represents the first barrier against food contaminants as well as the first target for these toxicants. Deoxynivalenol (DON) is a mycotoxin that commonly contaminates cereals and causes various toxicological effects. Through consumption of contaminated cereals and cereal products, human and pigs are exposed to this mycotoxin. Using in vitro, ex vivo, and in vivo approaches, we investigated the effects of DON on the intestinal epithelium. We demonstrated that, in intestinal epithelial cell lines from porcine (IPEC-1) or human (Caco-2) origin, DON decreases trans-epithelial electric resistance (TEER) and increases in a time and dose-dependent manner the paracellular permeability to 4 kDa dextran and to pathogenic Escherichia Coli across intestinal cell monolayers. In pig explants treated with DON, we also observed an increased permeability of intestinal tissue. These alterations of barrier function were associated with a specific reduction in the expression of claudins, which was also seen in vivo in the jejunum of piglets exposed to DON-contaminated feed. In conclusion, DON alters claudin expression and decreases the barrier function of the intestinal epithelium. Considering that high levels of DON may be present in food or feed, consumption of DON-contaminated food/feed may induce intestinal damage and has consequences for human and animal health

The ‘magic tail’ of G protein-coupled receptors: an anchorage for functional protein networks

AbstractAll cell types express a great variety of G protein-coupled receptors (GPCRs) that are coupled to only a limited set of G proteins. This disposition favors cross-talk between transduction pathways. However, GPCRs are organized into functional units. They promote specificity and thus avoid unsuitable cross-talk. New methodologies (mostly yeast two-hybrid screens and proteomics) have been used to discover more than 50 GPCR-associated proteins that are involved in building these units. In addition, these protein networks participate in the trafficking, targeting, signaling, fine-tuning and allosteric regulation of GPCRs. To date, proteins that interact with the GPCR C-terminus are the most abundant and are the focus of this review

Laser-Induced Linear Electron Acceleration in Free Space

Linear acceleration in free space is a topic that has been studied for over 20 years, and its ability to eventually produce high-quality, high energy multi-particle bunches has remained a subject of great interest. Arguments can certainly be made that such an ability is very doubtful. Nevertheless, we chose to develop an accurate and truly predictive theoretical formalism to explore this remote possibility in a computational experiment. The formalism includes exact treatment of Maxwell's equations, exact relativistic treatment of the interaction among the multiple individual particles, and exact treatment of the interaction at near and far field. Several surprising results emerged. For example, we find that 30 keV electrons (2.5% energy spread) can be accelerated to 7.7 MeV (2.5% spread) and to 205 MeV (0.25% spread) using 25 mJ and 2.5 J lasers respectively. These findings should hopefully guide and help develop compact, high-quality, ultra-relativistic electron sources, avoiding conventional limits imposed by material breakdown or structural constraints.Comment: Supplementary Information starts on pg 1

Effect of oxidoreduction potential and of gas bubbling on rheological properties and microstructure of acid skim milk gels acidified with glucono-delta-lactone

Milk oxidoreduction potential was modified using gases during the production of a model dairy product and its effect on gel setting was studied. Acidification by glucono-δ-lactone was used to examine the physicochemistry of gelation and to avoid variations due to microorganisms sensitive to oxidoreduction potential.Four conditions of oxidoreduction potential were appliedto milk: milk was gassed with air, nongassed, gassed with N2, or gassed with N2H2. The rheologicalproperties and microstructure of these gels were determined using viscoelasticimetry, measurement of whey separation, and confocal laser scanning microscopy. It appeared that a reducing environment led to less-aggregated proteins within the matrix and consequently decreased whey separation significantly. The use of gas to modify oxidoreduction potential is a possible way to improve the quality of dairy products

Charting a New Course

Infrastructure plays a key role in promoting economic growth and opportunities.In particular, the efficient provision of basic infrastructure services, like water and sanitation, is a key ingredient in fostering a country's social and economic development. Previous studies have found that infrastructure has a positive impact on output, and can improve economic opportunity, including health and education for the poor, particularly in developing countries. In Argentina, a 2005 study, found that child mortality fell by 8 percent in areas that had experienced improved coverage and quality of basic water and sanitation through utility reform, with most of the reduction occurring in low-income areas where the water network expanded the most. More generally, Fay and Morrison found that allowing the poorest quintile in developing countries the same access to basic services as the richest quintile would reduce child mortality by 8 percent and child under development by 14 percent. Calderon and Serven also found a significant positive impact of infrastructure access and quality on overall inequality. Furthermore, the book sheds some light on how to address the main challenge for the future which may be to attract specialized operators to the smaller municipalities which do not currently have them. For that purpose in Colombia, for example, over the last two years, the policy framework has been focused on promoting the sector's development, by using the departments as the intermediate institutional level between the National Government and the municipalities, to formulate programs with regional impact and promote comprehensive investment plans. Document type: Boo