Comparison of parametric methods for modeling corneal surfaces

Corneal topography is a medical imaging technique to get the 3D shape of the cornea as a set of 3D points of its anterior and posterior surfaces. From these data, topographic maps can be derived to assist the ophthalmologist in the diagnosis of disorders. In this paper, we compare three different mathematical parametric representations of the corneal surfaces leastsquares fitted to the data provided by corneal topography. The parameters obtained from these models reduce the dimensionality of the data from several thousand 3D points to only a few parameters and could eventually be useful for diagnosis, biometry, implant design etc. The first representation is based on Zernike polynomials that are commonly used in optics. A variant of these polynomials, named Bhatia-Wolf will also be investigated. These two sets of polynomials are defined over a circular domain which is convenient to model the elevation (height) of the corneal surface. The third representation uses Spherical Harmonics that are particularly well suited for nearly-spherical object modeling, which is the case for cornea. We compared the three methods using the following three criteria: the root-mean-square error (RMSE), the number of parameters and the visual accuracy of the reconstructed topographic maps. A large dataset of more than 2000 corneal topographies was used. Our results showed that Spherical Harmonics were superior with a RMSE mean lower than 2.5 microns with 36 coefficients (order 5) for normal corneas and lower than 5 microns for two diseases affecting the corneal shapes: keratoconus and Fuchs’ dystrophy

Comparison of quasi-spherical surfaces : application to corneal biometry

In this study, the authors present two new techniques with their own particular advantages dedicated to the authentication of a person based on the three-dimensional geometry of the cornea. A device known as corneal topographer is used for capturing the shape of each cornea. Until now only a few studies on corneal biometry have been conducted and they were limited only to the anterior surface. In this study, since the whole cornea is a tissue layered by two (anterior and posterior) surfaces, the authors propose to use both surfaces to characterise the corneal shape. The first proposed method consists of comparing coefficients from a spherical harmonics decomposition, and this allows to do a fast comparison that can be used to perform many-to-one comparisons. The second approach is based on the minimal residual volume between two corneas after a registration step, this geometry-based method is more accurate but slower, and is thus used to perform one-to-one comparisons. A cascade fusion scheme is also proposed to benefit from the advantages of both methods. The authors’ study demonstrates that corneal shape could be used for biometry. The two proposed methods have been tested and validated on a dataset of 257 corneas

PERCEPÇÕES E EXPECTATIVAS DE MORADORES DO GRANDE RECIFE-PE EM RELAÇÃO AOS PARQUES URBANOS

Procurou-se conhecer a concepção de recifenses sobre parques urbanos, indagando a uma amostra de 70 entrevistados, quais os parques urbanos da cidade. Além disso, procurou-se saber quais desses espaços livres eram freqüentados, que atividadeseram ali desenvolvidas e o que cada um esperava encontrar. Dois parques urbanosforam reconhecidos pela maioria dos entrevistados e apresentaram mais de 80% de taxa de freqüência entre aqueles que se disseram usuários de parques, sendo ambos, Parque da Jaqueira e Parque Treze de Maio, os maiores e os mais arborizados da cidade. Alguns locais considerados oficialmente como parques urbanos não foram assim percebidos pelos entrevistados que, por outro lado, apontaram outras categorias de áreas verdes que não têm o título, mas exercem a função de parque urbano. A grande maioria das pessoas disse buscar um parque para caminhar, passear,namorar, conversar, meditar, descansar, relaxar e praticar esportes, relacionando uma série de itens necessários. Concluiu-se que a necessidade de novos parques urbanos em Recife é evidente, devendo levar em conta, no planejamento, os anseios das pessoas, que desejam correr, brincar, divertir-se, e se relacionar com outras pessoas,em um ambiente arborizado, tranqüilo, seguro, voltado à contemplação dos elementos naturais e ao gozo dos serviços ambientais proporcionados por essa categoria de área verde

Real-Time Locating System to study the persistence of sociality in large-mammal group dynamics

Je n'ai pas encore les pages des proceedingsReal-Time Locating System to study the persistence of sociality in large-mammal group dynamics. European Conference on Precisions Livestock Farming (ECPLF

Le "De bello ciuili" de Lucain, une parole en mutation (de la rhétorique républicaine à une poétique de la guerre civile)

Les deux premiers chants de Lucain témoignent d une utilisation novatrice des discours directs dans l épopée. Présentés sous forme de triades de paroles juxtaposées le dialogue n est plus possible dans le monde du De bello ciuili- dont l objectif et le genre sont similaires, ils incitent le lecteur-auditeur de l Antiquité, rompu aux joutes oratoires des concours de déclamation, à les comparer. L examen de deux de ces groupes de discours sert de préliminaire à une enquête plus large sur la parole rhétorique, puis sur la parole poétique.Dans la confrontation des discours de la première triade (Curion / César /Laelius, au chant I) se lit la condamnation de l éloquence traditionnelle fondée sur des valeurs éthiques universellement partagées. Elle est supplantée par une rhétorique sophistique qui redéfinit, exclusivement en fonction des intérêts personnels de l orateur, tout ce qui a trait au droit, au juste ou à la citoyenneté, notions problématiques dans le contexte de perversion morale du bellum ciuile. L efficacité de cette nouvelle éloquence est signalée par le succès des trois suasoires qui sont à l origine des grands tournants narratifs de l œuvre : Curion décide César à entrer définitivement dans l affrontement civil (Chant I), Cicéron pousse Pompée à donner le signal du début du combat à Pharsale (Chant VII) et Pothin persuade Ptolémée d assassiner Magnus (Chant VIII).Dans la comparaison des trois paroles prophétiques de la fin du livre I auxquelles répondent les trois discours du début du chant suivant, effusions angoissées de Romains anonymes (les femmes, les hommes et le vieillard), se dessine un art poétique destiné à justifier les choix génériques du poète pour traiter son sujet. Conformant son œuvre à la médiocrité humaine des masses, il doit renoncer au genre tragique (discours des femmes) ainsi qu à la célébration épique des héros (discours des hommes) et s efforcer de proposer, à l instar du vieillard qui se remémore le passé pour anticiper le futur (le plus long discours de l épopée, rappelant, par sa place et son sujet, l ilioupersis d Enée), une épopée historique qui cherche à percer l opacité du monde de la guerre civile, dans lequel les dieux ne sont plus anthropomorphes. Empruntant leur esthétique du déchiffrement du réel aux Piérides ovidiennes, ces poétesses humaines, rivales des divines Muses (Métamorphoses V), Lucain refonde alors la persona de son uates. Chantre d un genre nouveau, pour une épopée renouvelée, le piéridique uates du De bello ciuili qui ne peut plus être omniscient puisque les pensées et les actions des superi lui sont inconnaissables- refuse le patronage des divinités traditionnelles de la poésie, promet à son héros César, non la gloire mais l exécration éternelle et proclame avec défi, qu il ne devra lui-même l éternité qu à la seule puissance de son talent personnel, divines Muses et grands guerriers héroïques des œuvres du passé ayant été congédiés par la guerre civile.The first two books of Lucan reveal an innovative use of direct speech in epic. Presented as contiguous speech triads dialogs being impossible in the realm of De bello ciuili whose purpose and genre are similar, they lead the ancient reader-listener, used to oral debates typical of declamation contests, to compare them. The investigation of two of these speech groups is our first step to a larger inquiry on rhetoric speech, then on poetic speech.Confronting the speech of the first triad (Curion/Caesar/Laelius in book I) reveals the end of traditional eloquence based on universal ethic values. It is superseded by a sophistic rhetoric that redefines (exclusively according to the speaker's private interests) whatever relates to law, justice or citizenship problematic concepts in the perverse moral context of bellum ciuile. The efficiency of this new eloquence is highlighted by the success of the three suasory performances which cause the work's main narrative turns: Curion convinces Caesar to definitely take part to the civil war (book I), Cicero leads Pompeus to launch the battle at Pharsalia (book VII) and Pothinus persuades Ptolemy to murder Magnus (book VIII).Comparing the three prophetic speeches at the end of book I (which mirror the three speeches at the beginning of the following book), anxious complains of anonimous Romans (the women, the men and the elderly), we identify an art of poetry aimed at motivating the generic choices made by the poet to handle his subject. Working along the lines of the human depravity of masses, he may not employ neither the tragic style (the speech of women) nor the epic celebration of heroes (the speech of men), but must suggest as the old man remembers the past to anticipate the future (the longest speech of the epic reminds Eneas Ilioupersis by means of its place and subject) an historical epic aiming at enlightening the opaque world of civil war, in which the gods are no longer anthropomorphic. Borrowing their deciphering aesthetic to Ovids Pierides, human female poets rivaling the godly Muses (Metamorphosis V), Lucan reinvents the persona of his uates. Promoting a new genre, for a renewed epic, the 'pieridic' uates of De Bello Ciuili, which can no longer be omniscient since the superi's thoughts and deeds are out of his reach refuses to worship the traditional poetry deities, swears to his 'hero' Caesar not the glory but the eternal hatred and defiantly proclaims that he himself will deserve eternity only through his own talent, the godly Muses and great heroic warriors of ancient works having been dismissed by civil war.PARIS-EST-Université (770839901) / SudocPARIS12-Bib. électronique (940280011) / SudocSudocFranceF

Le diagnostic précoce des troubles du comportement externalisé est-il fiable ? Mise à l’épreuve d’une procédure multi informateurs et multi méthodes

peer reviewedCette contribution questionne la fiabilité du diagnostic précoce des troubles du comportement externalisé chez l’enfant. Les données concernant le comportement de 118 enfants ont été collectées par questionnaires et observation auprès de leurs parents, leurs enseignants et les cliniciens lors du recrutement et après 12 mois. Les résultats montrent des variations importantes dans le nombre d’enfants atteignant un seuil clinique selon l’informateur et la méthode considérés. Une méthode combinant les évaluations des informateurs pour obtenir un diagnostic valide est éprouvée. Les résultats plaident en faveur d’une procédure multi-informateurs et multiméthodes dont les implications sont discutées sur le plan clinique et de la recherche.H2M childre

Film formation analysis by diffusive wave spectroscopy

The thin layer analysis is very important for several sectors of industry. Indeed, environmental laws and improvement of performances lead the manufacturers to innovate in the field of coatings and paints. Several classical techniques of characterization (TGA, DMA, etc.) used with this intention do not allow to perform the analysis in situ and are often long and tedious to set up. We propose to solve this problem with a newoptical process. Its technology based on multi-speckle diffusivewave spectroscopy (MS-DWS) allows making real-time analysis in a non-destructive way thanks to an optical measurement. The aim of this work is to highlight correlations between this new technology and the classical methods of analysis. Two film forming polymeric materials were studied, a polydimethylsiloxane (PDMS) and a commercial paint based on an aqueous dispersion of acrylic copolymers. The PDMSwas chosen for the simplicity of its film forming process and is used as model. The paint having a more complex drying mechanism enables to complete this study

USO DE ESPECIES PRODUTORAS DE TANINOS PARA CURTIMENTO DE PELES NO NORDESTE DO BRASIL

Este trabalho sintetiza informações sobre sistemas de curtimento de peles no Nordeste do Brasil, identificando origem dos tanantes empregados e formas de usos da vegetação nativa da caatinga para essa finalidade. Dados secundários foram obtidos da literatura especializada e informações de campo originaram-se de observações e entrevistas em curtumes tradicionais e empresariais em Pernambuco e Bahia. A produção dos tanantes vegetais dá-se em dois ambientes distintos: o da silvicultura moderna e tecnificada, representada por empresas do sul do Brasil, fornecedoras de taninos industrializados, e o do extrativismo local, de baixa tecnologia, descapitalizado e com baixa produtividade. Diferentes espécies conhecidas popularmente como angicos e juremas são apontadas com produtoras de taninos mas esse produto é apenas empregado no curtimento tradicional, não raro associado ao corte clandestino de madeira. Curtumes empresariais utilizam principalmente cromo para curtimento, enquanto o produto de origem vegetal industrializado é empregado no recurtimento. Não se encontraram parâmetros técnicos e econômicos que possibilitem a regulamentação da exploração e o fomento da produção sustentável do tanino como produto não madeireiro da Caatinga