Impact of a Community Association on Integrated Suburban Housing Patterns

Community associations-neighbors who join together in recognition of common interests and sometimes in pursuit of greater political influence-appear and disappear with the ebb and flow of local issues. Home community organizations have concerned themselves with installation of improvements, such as sidewalks and sewers; others, with the quality of municipal services, property maintenance, and compliance with building and zoning laws. More recently, however, such community organizations have sprung into life for the purpose of dealing with the emotionally-charged issue of racial integration in their neighborhoods. This paper will explore the development of The Lomond Association, a community organization committed to a belief in racial integration, and will trace its impact on housing patterns within its jurisdictio

Impact of a Community Association on Integrated Suburban Housing Patterns

Community associations-neighbors who join together in recognition of common interests and sometimes in pursuit of greater political influence-appear and disappear with the ebb and flow of local issues. Home community organizations have concerned themselves with installation of improvements, such as sidewalks and sewers; others, with the quality of municipal services, property maintenance, and compliance with building and zoning laws. More recently, however, such community organizations have sprung into life for the purpose of dealing with the emotionally-charged issue of racial integration in their neighborhoods. This paper will explore the development of The Lomond Association, a community organization committed to a belief in racial integration, and will trace its impact on housing patterns within its jurisdictio

Réactivité et manipulation de nanotubes de carbone monocouches : fonctionnalisation de surface par greffage covalent et mise en oeuvre comme agent structurant.

This thesis work is concerned with the use of single-walled carbon nanotubes (SWNTs) as structural directing agent, and with the covalent grafting of SWNTs in order to modify their surface properties. In the first part, we discuss the use of SWNTs as structural directing agent in the synthesis, in the hydrothermal way, of mesoporous aluminosilicates. Some composites presenting the MCM-41 structure are thus formed. They are characterized by electronic microscopy, Raman diffusion, X-ray diffraction and adsorption-desorption of N2. Isolated nanotubes in the mesopores were observed with transmission microscopy, but the structure of the composites is not yet well defined. The second part deals with the fluorination of SWNTs with F2. The spectroscopic evolutions of fluorinated buckypapers are discussed as a function of growing amounts of grafted fluorine. The good solvation properties of C2F fluorotubes in isopropanol is highlighted by atomic force microscopy (observation of a majority of isolated tubes, and not bundles). The defluorination reaction, using hydrazine, has been studied with Raman diffusion, first upon solvated fluorotubes, then upon isolated fluorotubes deposited on a surface. The evolution of the radial breathing modes, observed after defluorination, are explained by the bundle effect. The last chapter is focused on the grafting of aryl groups on SWNTs, using the electrochemical reduction of diazonium salts. Thin films made of nanotubes are utilized as a work electrode in a constant potential device. The grafting of 4-bromophenyl, 4-carboxyphenyl and 4-chloromethylphenyl groups are characterized with Raman diffusion and X-ray photoelectron spectroscopy. The possibility of coupling some grafted aryls and other groups has been explored upon nanotubes functionalised with 4-chloromethylphenyls (nucleophilic substitutions with amines and diamines).Ce travail de thèse est consacré à l'utilisation de nanotubes de carbone monocouches (SWNTs) comme agent structurant, ainsi qu'au greffage covalent de SWNTs en vue de modifier leurs propriétés de surface. La première partie traite de l'emploi de SWNTs comme agent structurant dans la synthèse, par voie hydrothermale, d'aluminosilicates mésoporeux de type MCM-41. Les composites qui en résultent sont caractérisés par microscopie électronique, diffusion Raman, diffraction des rayons X et adsorption-désorption de N2. La microscopie à transmission a permis d'observer la présence de nanotubes isolés au sein des mésopores, mais la structure des composites n'est pas encore clairement élucidée. La deuxième partie aborde la fluoration de SWNTs par F2. Les évolutions spectroscopiques de buckypapers fluorés sont suivies en fonction de stoechiométries CnF croissantes. La bonne solubilité des fluorotubes C2F dans l'isopropanol est mise en évidence par microscopie à force atomique (observation d'une majorité de tubes isolés, et non pas de fagots). La réaction de défluoration, utilisant l'hydrazine, a été étudiée par diffusion Raman, d'abord sur des fluorotubes en solution, puis sur des fluorotubes isolés préalablement déposés sur une surface. Les évolutions des modes radiaux observées après défluoration sont expliquées par l'effet fagot. Le dernier chapitre traite du greffage de groupes aryles sur des SWNTs, par réduction électrochimique de sels de diazonium. Des films minces de nanotubes sont employés comme électrode de travail dans un montage à potentiel constant. Les greffages de groupes 4-bromophényles, 4-carboxyphényles et 4-chlorométhylphényles ont été caractérisés par spectroscopies de diffusion Raman et de photoélectrons X. La possibilité d'effectuer des couplages entre les aryles greffés et d'autres groupes a été explorée sur les nanotubes fonctionnalisés par les 4-chlorométhylphényles (substitutions nucléophiles par des amines et diamines)

Piezoelectric nanoelectromechanical resonators based on aluminum nitride thin films

We demonstrate piezoelectrically actuated, electrically tunable nanomechanical resonators based on multilayers containing a 100-nm-thin aluminum nitride (AlN) layer. Efficient piezoelectric actuation of very high frequency fundamental flexural modes up to ~80 MHz is demonstrated at room temperature. Thermomechanical fluctuations of AlN cantilevers measured by optical interferometry enable calibration of the transduction responsivity and displacement sensitivities of the resonators. Measurements and analyses show that the 100 nm AlN layer employed has an excellent piezoelectric coefficient, d_(31)=2.4 pm/V. Doubly clamped AlN beams exhibit significant frequency tuning behavior with applied dc voltage

Arytenoïdectomy in the horse. surgical indications. prognosis

L’inflammation chronique des cartilages aryténoïdiens du cheval est une pathologie qui peut ressembler à l’hémiplégie laryngée (cornage) du cheval. Le seul traitement chirurgical qui donne des résultats valables consiste à exciser partiellement ou totalement le cartilage aryténoïde. Le pronostic est réservé mais on peut espérer un succès total dans certains cas.The chronic inflammation of the arytenoid cartilage of the larynx in the horse can produce clinical signs similar to those encountered in laryngeal hemiplegia (roarer). The surgical treatment of the condition consists in removing part or the whole arytenoid cartilage. The prognosis is guarded although complete recovery is possible

Lie Isomorphisms of Nest Algebras

AbstractIn this paper we characterize linear mapsϕbetween two nest algebras T(N) and T(M) which satisfy the property thatϕ(AB−BA)=ϕ(A)ϕ(B)−ϕ(B)ϕ(A) for allA, B∈T(N). In particular, it is shown that such isomorphisms only exist if N is similar to M or M⊥

Permo-Triassic Deposits: from shallow water to base of slope

Conference on the Geology of Oman, Muscat, Oman, Field Guidebook A0

Multi-Armed Bandits for Correlated Markovian Environments with Smoothed Reward Feedback

We study a multi-armed bandit problem in a dynamic environment where arm rewards evolve in a correlated fashion according to a Markov chain. Different than much of the work on related problems, in our formulation a learning algorithm does not have access to either a priori information or observations of the state of the Markov chain and only observes smoothed reward feedback following time intervals we refer to as epochs. We demonstrate that existing methods such as UCB and $\varepsilon$-greedy can suffer linear regret in such an environment. Employing mixing-time bounds on Markov chains, we develop algorithms called EpochUCB and EpochGreedy that draw inspiration from the aforementioned methods, yet which admit sublinear regret guarantees for the problem formulation. Our proposed algorithms proceed in epochs in which an arm is played repeatedly for a number of iterations that grows linearly as a function of the number of times an arm has been played in the past. We analyze these algorithms under two types of smoothed reward feedback at the end of each epoch: a reward that is the discount-average of the discounted rewards within an epoch, and a reward that is the time-average of the rewards within an epoch.Comment: Significant revision of prior version including deeper discussion of related work, gap-independent regret bounds, and regret bounds for discounted reward