Highly separated transonic flows

Attention is given to the wind tunnel, to photographic visualization of the flow, and to measurements by pressure probes, hot wire anemometry and laser anemometry. The simultaneous use of different means of measurement provided a good description of the phenomenon, and indicated the existence of shocks and their stability, as well as the existence of the bubble, its dimensions, and in particular, the reattachment of its front. The results show that the bursting (or transition) of the bubble front is produced at an unstable position and creates a point of turbulent intensity which diffuses over the entire height of the flow

The preparation of the National Environmental Action Plan (NEAP): Was it a false start?

In the late 80’s, the World Bank got interested in environmental matters, to the point that a tsunami of a new process (National Environmental Action Plans – NEAPs) swept across the African continent. At that time, Madagascar was still under the rule of Didier Ratsiraka, an iron rule which had started in 1975. A place where biodiversity assets are unique and fascinating, one of the best and hottest hotspots of conservation around the world; but also a place where environmental mismanagement has created severe erosion and water quality problems. What to do when the daily life of the average Malagasy is spent surviving for the very sector sustaining the country’s battling economy? Some of the solutions proposed at the time materialized during the 15 years period since the 1990 adoption by the Malagasy government of the NEAP’s findings and recommendations. Some of the original intentions, however, never were transformed into significant large-scale progress in environmental management. In 2006, Madagascar is still plagued with very serious poverty and environmental degradation problems. Can the lessons learned from the original design and the 15 years of application of the NEAP be useful to help the Malagasy nation move towards more sustainable and equitable development? If the answer is yes, what should the ways and means be

Revisiting deforestation in Africa (1990–2010): One more lost generation

This spotlight revisits the dynamics and prognosis outlined in the late 1980’s published in Déforestation en Afrique. This book on deforestation in Africa utilized available statistical data from the 1980’s and was a pioneering self - styled attempt to provide a holistic viewpoint of the ongoing trends pertaining to deforestation in Africa; of root causes and of the challenges facing the conservation community. Here, the same author searches for an explanation for the ‘commercial fiasco’ of that book and uses the recent Global Forest Resource Assessment (GFRA) published by the Food and Agriculture Organisation (FAO, 2010), concluding that (i) this overall prognosis turned out to be slightly pessimistic vs. the actual forest evolution as recorded by FAO, but that (ii) deforestation in Africa still continues at 0.5 % per annum, and (iii) success stories are few and Africa remains the continent where major deforestation continues apace. The analysis of ten African countries ‘at risk’ because of a combination of an economic slump coupled with a high deforestation rate confirms a likely relationship between these two factors. The lack of attention paid to deforestation in Africa raises concerns that “throwing money at the problem” – the best solution that the international community has found so far – may not be constructive in the least.RÉSUMÉUn livre publié en 1991, écrit par l’auteur utilisait les données statistiques des années 80 sur les forêts Africaines, données telles que disponibles à l’époque. Ce livre représentait une première tentative, non sollicitée, de fournir un tableau holistique des tendances d’alors sur la déforestation en Afrique, de s’interroger sur les causes profondes de ce phénomène et sur les défis à relever dans ce domaine. Dans le présent article, l’auteur cherche les raisons du fiasco commercial du livre et effectue des calculs sur les données les plus récentes sur les forêts Africaines telles que publiées par l’Organisation des Nations-unies pour l’agriculture et l’alimentation (plus connue sous son sigle anglais FAO). Les principales conclusions de cette rapide analyse sont (i) les projections sur le futur des forêts Africaines effectuées dans le livre de 1991 se révèlent marginalement pessimistes par rapport à la réalité observée (sur la base des projections de 1991 et sur une base 100 en 1990, les forêts africaines restantes seraient dans une fourchette de 77,2 à 87,8 % , l’indice réel étant 89,9 % ), cependant, (ii) la déforestation continue en Afrique à un rythme de 0,5 % l’an, peu différent du taux de 0,56 % dans les années 90 et (iii) les réussites Africaines dans la lutte contre la déforestation sont peu nombreuses et ce continent reste le plus exposé à ce fléau dans le monde. Le livre de 1991 contenait également l’identification de dix pays Africains « à risque » à cause d’un cumul de stagnation économique et de fort taux de déforestation. L’observation des évolutions récentes confirme que ces pays sont « mal partis ». En conclusion, l’auteur regrette le manque d’attention à la déforestation en Afrique, au moment même où le monde célèbre « Rio + 20 » ; l’auteur craint également que la tactique habituelle de la communauté internationale « jeter de l’argent sur le problème » ne fonctionne pas, des causes fondamentales de la déforestation comme le manque de politiques publiques efficaces ou la corruption endémique réclamant plus que de l’argent pour être extirpées

Market Structure and Competition in Food Retail: Some Evidences from Brazil

The paper analyzes competition among supermarkets in Brazil. In contrast to part of the economic literature which suggests that the fast growth of big supermarket chains would destroy independent, medium and small supermarkets, the paper argues that big supermarket chains can coexist with different formats of independent food retailing. As a result, competition in food retail is complex and cannot be described as a simple Darwinian process of market concentration. The analysis is divided in two parts. In the first part, the competition between hypermarkets and supermarkets is examined. Evidences for the district of Sao Paulo, Brazil, suggest that these retailers form separate markets. The second part is focused on neighborhood supermarkets. The results differ from the general belief that independent supermarkets establish higher prices in comparison to big chain supermarkets. The analysis brings to light the heterogeneity of the competitive fringe in the oligopoly model of Brazilian retailing.Food retail, Supermarkets, Differentiation, Agribusiness, Industrial Organization,

Diffraction of a Bose-Einstein Condensate in the Time Domain

We have observed the diffraction of a Bose-Einstein condensate of rubidium atoms on a vibrating mirror potential. The matter wave packet bounces back at normal incidence on a blue-detuned evanescent light field after a 3.6 mm free fall. The mirror vibrates at a frequency of 500 kHz with an amplitude of 3.0 nm. The atomic carrier and sidebands are directly imaged during their ballistic expansion. The locations and the relative weights of the diffracted atomic wave packets are in very good agreement with the theoretical prediction of Carsten Henkel et al. [1].Comment: submitted to Phys. Rev.

Teegi: Tangible EEG Interface

We introduce Teegi, a Tangible ElectroEncephaloGraphy (EEG) Interface that enables novice users to get to know more about something as complex as brain signals, in an easy, en- gaging and informative way. To this end, we have designed a new system based on a unique combination of spatial aug- mented reality, tangible interaction and real-time neurotech- nologies. With Teegi, a user can visualize and analyze his or her own brain activity in real-time, on a tangible character that can be easily manipulated, and with which it is possible to interact. An exploration study has shown that interacting with Teegi seems to be easy, motivating, reliable and infor- mative. Overall, this suggests that Teegi is a promising and relevant training and mediation tool for the general public.Comment: to appear in UIST-ACM User Interface Software and Technology Symposium, Oct 2014, Honolulu, United State

High Tech Lending: Maintaining Priority in an Intangible World

Financing intangible intellectual property in Canada presents some novel demands on lenders because of the interaction of provincial security schemes with federal intellectual property legislation. This article looks at the relative ease with which security interests in intangible property may be obtained under provincial personal property security regimes, and then at the various federal intellectual property statutes which exhibit more of a piecemeal approach to financing. In addition, a number of constitutional issues arise because of this jurisdictional split, and the article explores these issues, comparing the situation in Canada with that in the United States. The article suggests that unless legislative reform occurs, a cautious and pragmatic approach to securing intangible assets in Canada is warranted

Anomalous Roughening of Viscous Fluid Fronts in Spontaneous Imbibition

We report experiments on spontaneous imbibition of a viscous fluid by a model porous medium in the absence of gravity. The average position of the interface satisfies Washburn's law. Scaling of the interface fluctuations provides a dynamic exponent z \simeq 3, indicative of global dynamics driven by capillary forces. The complete set of exponents clearly shows that interfaces are not self-affine, exhibiting distinct local and global scaling, both for time (b=0.64\pm 0.02, b* =0.33 \pm 0.03) and space (a=1.94 \pm 0.20, a_loc=0.94 \pm 0.10). These values are compatible with an intrinsic anomalous scaling scenario.Comment: 4 pages, 5 figure