Spacetime deployments parametrized by gravitational and electromagnetic fields

On the basis of a "Punctual" Equivalence Principle of the general relativity context, we consider spacetimes with measurements of conformally invariant physical properties. Then, applying the Pfaff theory for PDE to a particular conformally equivariant system of differential equations, we make explicit the dependence of any kind of function describing a "spacetime deployment", on n(n+1) parametrizing functions, denoting by n the spacetime dimension. These functions, appearing in a linear differential Spencer sequence and determining gauge fields of spacetime deformations relatively to a "substrat spacetime", can be consistently ascribed to unified electromagnetic and gravitational fields, at any spacetime dimensions n greater or equal to 4.Comment: 26 pages, LaTeX2e, file macro "suppl.sty", correction in the definition of germs and local ring

Fiscal competition in developing countries : a survey of the theoretical and empirical literature

The last two decades have witnessed a sharp increase in foreign direct investment (FDI) flows and increased competition among developing countries to attract FDI, resulting in higher investment incentives offered by host governments and removal of restrictions on operations of foreign firms in their countries. Fiscal competition between governments can take the form of business tax rebates, productivity-enhancing public infrastructure or investment incentives such as tax holidays, accelerated depreciation allowances or loss carry-forward for income tax purposes. It can take place between governments of different countries or between local governments within the same country. This paper surveys the recent theoretical and empirical economic literature on decentralization which attempts to answer three questions. First, does theoretical literature on fiscal competition and"bidding races"contribute to a better understanding of such phenomenon in developing countries? Second, are FDI inflows in developing countries sensitive to fiscal incentives and is there empirical evidence of strategic behavior from the part of developing countries in order to attract FDI? Third, what evidence is there about fiscal competition among local governments in developing countries?Subnational Economic Development,Debt Markets,Taxation&Subsidies,Emerging Markets,Public Sector Economics

The time-inconsistency of alternative energy policy

Time-inconsistency can arise when a government attempts to convince private sector to use a particular alternative energy (gas, green electricity...) rather than petroleum products. By introducing taxes and feed-in prices, a government would encourage firms and households to switch to an alternative energy rather than use petroleum products. However, even if a government is in favor of increasing alternative energy consumption, it can benefit from considerable financial resources resulting from petroleum product consumption. As a result of these conflicting issues, the private sector may not find the alternative energy policy credible, which prevents the government to implement a socially efficient policy.Time-inconsistency Energy policy Tax expenditures

Measurement of thermal conductance of silicon nanowires at low temperature

We have performed thermal conductance measurements on individual single crystalline silicon suspended nanowires. The nanowires (130 nm thick and 200 nm wide) are fabricated by e-beam lithography and suspended between two separated pads on Silicon On Insulator (SOI) substrate. We measure the thermal conductance of the phonon wave guide by the 3 method. The cross-section of the nanowire approaches the dominant phonon wavelength in silicon which is of the order of 100 nm at 1K. Above 1.3K the conductance behaves as T3, but a deviation is measured at the lowest temperature which can be attributed to the reduced geometry

Communauté d'apprentissage et communauté de pratique en<br />ligne : le processus réflexif dans la formation des formateurs

Recent educational policies are oriented towards thetraining of teachers for online collaborative work.We size this opportunity to examine the delicaterelationship between reflective practice andcommunity of practice. Keeping in mind theprofessional development of teachers, we stress theinterest of developing trainings which support theemergence of communities of practice and raise theawareness about new instructional strategies. Weintroduce a paradigm which articulates fournotions, namely reflection on practice, dialogue inthe reflective process, learning community andcommunity of practice. We describe a frameworkfor reflection integrated into a collaborative learningprocess, its specific media of discourse, scenario anddialogical process. A case study illustrates ourapproach.Saisissant l'occasion offerte par de récentes politiques éducatives qui orientent la formation des enseignants vers le travail collectif en réseaux, nous abordons ici la délicate question de l'association entre pratique réflexive et participation à des communautés de pratique en ligne. Motivés par le développement professionnel de l'enseignant, nous montrons l'intérêt de concevoir des formations qui ont pour enjeux d'être un terreau favorisant l'émergence de communautés de pratique en ligne et d'ouvrir les praticiens à de nouvelles postures pédagogiques. Nous présentons un paradigme qui articule quatre notions : réflexion sur les pratiques, cadre dialogique pour le processus réflexif, communauté d'apprentissage et communauté de pratique. Nous décrivons un dispositif de travail réflexif intégré au sein d'une formation collaborative avec ses supports d'expression, son scénario et son processus dialogique. L'ensemble est illustré par une étude de cas portant sur une formation de formateurs qui s'est répétée sur deux années consécutives

Graphic Interrogation in Psychosocial Research: Deleuze AND Comics AND Middle-aged Men

The assemblage of comics, Deleuzian metaphysics and middle-aged men in the context of psychosocial research is an experiment in the sense that Deleuze advocates for the furtherance of thought. The works of Deleuze and Deleuze and Guattari can allow us, it is suggested, to bring together theoretical problems in comics theory with theoretical problems in psychosocial research and provide us with new insights as to how we might look at visual data qualitatively from participants who agreed to recount episodes of their relationships in graphic narrative form.Both psychosocial qualitative research and comics theory are new and fast moving fields which offer scope for creative thinking. It is argued in this thesis that the ‘affective’ and ‘visual’ turns, which are having an important impact in the social sciences, corresponds to the expressive function of comics, specially in the autobiographical, memoir and confessional genre.Having set the theoretical lens with the work of Deleuze and Guattari and some of their commentators, examples from commercially published works are examined in order to relate theory to empirical examination, prior to considering the work submitted by participants.Lastly, interspersed throughout the text and together as an appendix, I offer my own visual reflections in the comics mode which I believe dialogue with topics in the text, whilst remaining separate activities. That is to say I consciously avoid text or comic being an illustration of one another

Insulated container testing & rating system development

This research project seeks to develop a cheap, accurate, objective, repeatable and universal testing & rating system for insulated containers (eskies, chilly bins, coolers, ice boxes, cooler bags, pizza pouches, etc), similar to the star ratings for white goods, plumbing fixtures and motor vehicles, whether used for cold or hot items. Currently, there is no such system available on the domestic market, and none has been observed in any other market. The testing consists of placing an empty vessel in a chamber at 5°C, and waiting until its temperature is in equilibrium with that chamber, then transferring it to a chamber at 55°C, and again waiting until equilibrium is reached, and the time taken to reach equilibrium is observed. This process is then reversed as a double check to compare heat ingress and heat egress. The rating consists of taking the temperature differential and the time taken to reach steady-state and applying them to the volume of the vessel and the internal heat of air in the volume to determine a numerical result in W/K. The resultant number is the rating. This is far simpler than converting this into a number of stars (as is common with other ratings systems), and very quickly, consumers will begin to know the general range of numbers and be able to compare them to know what is sufficient for each of their needs. Successful tests have been carried out to demonstrate that this is a viable testing & rating system which stands to benefit the general community whenever a consumer chooses to purchase an insulated container. By displaying the results of such a testing & rating system, manufacturers can instil confidence for their customers that their purchase will meet their needs with respect to the thermal performance of the chosen product. This research project is ready to progress to a level of formulating a standard and a set of protocols with a view to starting commercial testing in established laboratories for existing manufacturers

Two-out-of-two color matching based visual cryptography schemes

International audienceVisual cryptography which consists in sharing a secret message between transparencies has been extended to color prints. In this paper, we propose a new visual cryptography scheme based on color matching. The stacked printed media reveal a uniformly colored message decoded by the human visual system. In contrast with the previous color visual cryptography schemes, the proposed one enables to share images without pixel expansion and to detect a forgery as the color of the message is kept secret. In order to correctly print the colors on the media and to increase the security of the scheme, we use spectral models developed for color reproduction describing printed colors from an optical point of view