4,168 research outputs found
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
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
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.
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
Construction of the probe beam photo-injector of CTF3
JACoW web site http://accelconf.web.cern.ch/AccelConf/e06This paper describes the HF (High-Frequency) and dynamic beam modelling performed onto the 3 GHz / 2,5 cells photo-injector of the future CTF3 (CLIC Test Facility 3) probe beam linac. The latter provides the beam to demonstrate the feasibility of the 30 GHz accelerating sections in the framework of the CLIC project. The Probe Beam Photo-Injector (PBPI) is inspired from the Drive Beam Photo-Injector (DBPI) already designed by LAL and actually tested in our laboratory. However, the design of PBPI has been simplified with respect to the previous because the charge per bunch is 4 times lower and the number of bunches several orders of magnitude smaller. The internal geometry and the coupling system of the PBPI have been designed with 2D (SUPERFISH*) and 3D (HFSS**) codes. Based on the modified design, PARMELA and POISSON simulations showed that the technical specifications are fulfilled. The vacuum issue has been also carefully investigated, and NEG (Non Evaporated Getter) technology has been adopted in order to reach the mbar pressure inside the structure. This work is done in deep collaboration with CEA/Saclay, which is responsible of the CTF3 Probe Beam Linac design and construction [1]
Asymmetry Function of Interstellar Scintillations of Pulsars
A new method for separating intensity variations of a source's radio emission
having various physical natures is proposed. The method is based on a joint
analysis of the structure function of the intensity variations and the
asymmetry function, which is a generalization of the asymmetry coefficient and
characterizes the asymmetry of the distribution function of the intensity
fluctuations on various scales for the inhomogeneities in the diffractive
scintillation pattern. Relationships for the asymmetry function in the cases of
a logarithmic normal distribution of the intensity fluctuations and a normal
distribution of the field fluctuations are derived. Theoretical relationships
and observational data on interstellar scintillations of pulsars (refractive,
diffractive, and weak scintillations) are compared. Pulsar scintillations match
the behavior expected for a normal distribution of the field fluctuations
(diffractive scintillation) or logarithmic normal distribution of the intensity
fluctuations (refractive and weak scintillation). Analysis of the asymmetry
function is a good test for distinguishing scintillations against the
background of variations that have different origins
Self-Propulsion of Immersed Objects via Natural Convection
Natural convection of a fluid due to a heated or cooled boundary has been studied within a myriad of different contexts due to the prevalence of the phenomenon in environmental and engineered systems. It has, however, hitherto gone unrecognized that boundary-induced natural convection can propel immersed objects. We experimentally investigate the motion of a wedge-shaped object, immersed within a two-layer fluid system, due to a heated surface. The wedge resides at the interface between the two fluid layers of different density, and its concomitant motion provides the first demonstration of the phenomenon of propulsion via boundary-induced natural convection. Established theoretical and numerical models are used to rationalize the propulsion speed by virtue of balancing the propulsion force against the appropriate drag force
The prominent role of the heaviest fragment in multifragmentation and phase transition for hot nuclei
The role played by the heaviest fragment in partitions of multifragmenting
hot nuclei is emphasized. Its size/charge distribution (mean value,
fluctuations and shape) gives information on properties of fragmenting nuclei
and on the associated phase transition.Comment: 11 pages, Proceedings of IWND09, August 23-25, Shanghai (China
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