33 research outputs found
Fractional Hamiltonian Monodromy from a Gauss-Manin Monodromy
Fractional Hamiltonian Monodromy is a generalization of the notion of
Hamiltonian Monodromy, recently introduced by N. N. Nekhoroshev, D. A.
Sadovskii and B. I. Zhilinskii for energy-momentum maps whose image has a
particular type of non-isolated singularities. In this paper, we analyze the
notion of Fractional Hamiltonian Monodromy in terms of the Gauss-Manin
Monodromy of a Riemann surface constructed from the energy-momentum map and
associated to a loop in complex space which bypasses the line of singularities.
We also prove some propositions on Fractional Hamiltonian Monodromy for 1:-n
and m:-n resonant systems.Comment: 39 pages, 24 figures. submitted to J. Math. Phy
Evaluation of a French parent-training program in young children with autism spectrum disorder = Ăvaluation d'un programme francophone de formation aux habiletĂ©s parentales dans le cadre des troubles du spectre de l'autisme auprĂšs d'un groupe pilote
Parent training programs (PTs) in young children with autism spectrum disorders (ASDs) are known to reduce parenting stress and improve child's behavior and parent-child interactions. Few PTs are available to French speaking families. In order to provide them with this type of intervention, we developed a French parent-training program of 12 bimonthly sessions and three individual home visits based on applied behavior analysis. The purpose of this study is to evaluate the social validity and efficacy of this new PT on eighteen parents who have a child with ASD and developmental delay. For 16 parents, the PT was considered effective, the objectives targeted important and the strategies learned acceptable for use with children. They have significantly improved their knowledge in ASD and behavioral intervention strategies and their children's socialization skills, and reduce their parental stress. This new French PT program seems to be a promising intervention. RĂ©sumĂ©. Objectifs : Le programme intitulĂ© « lâABC du comportement de lâenfant ayant un TSA : des parents en action ! » est un programme psychoĂ©ducatif de 12 sĂ©ances de 2 heures et de 3 visites Ă domicile destinĂ© aux familles de jeunes enfants ĂągĂ©s jusquâĂ 7 ans et ayant un trouble du spectre de lâautisme (TSA) avec retard de dĂ©veloppement. Ce programme de formation aux habiletĂ©s parentales (PFHP), basĂ© sur lâanalyse appliquĂ©e du comportement, a Ă©tĂ© dĂ©veloppĂ© en rĂ©ponse au besoin de formation des parents issus dâune population francophone pour faire face au stress quâengendrent les difficultĂ©s de comportement de leur enfant en environnement familial. Cette nouvelle intervention, offerte en groupe, a Ă©tĂ© proposĂ© Ă 30 parents sur un premier site francophone. Cette Ă©tude vise Ă Ă©valuer la validitĂ© sociale et lâefficacitĂ© de ce nouveau PFHP. MĂ©thode : Ce PFHP a Ă©tĂ© proposĂ© Ă trois groupes consĂ©cutifs de 4 à 6 familles. Il a Ă©tĂ© Ă©valuĂ© auprĂšs de 18 parents et 10 enfants. Pour Ă©valuer la validitĂ© sociale du programme, les parents ont rempli des questionnaires sur la signification sociale des objectifs ciblĂ©s, lâacceptabilitĂ© des procĂ©dures utilisĂ©es et lâimportance sociale des effets obtenus. LâefficacitĂ© du PFHP est Ă©valuĂ©e au travers de questionnaires remplis en prĂ©-intervention, post-intervention et en suivi trois mois aprĂšs la fin du programme. Ces questionnaires portent sur les connaissances des parents, le niveau de stress parental, les symptĂŽmes dĂ©pressifs et les comportements de lâenfant. RĂ©sultats : Parmi les 18 participants, 16 parents sont satisfaits de lâintervention. Ils considĂšrent les objectifs ciblĂ©s comme importants, les procĂ©dures transmises comme acceptables Ă utiliser et les compĂ©tences parentales dĂ©veloppĂ©es comme satisfaisantes. Le PFHP a Ă©tĂ© efficace tant au niveau des problĂ©matiques parentales que des acquisitions des enfants. Une augmentation des connaissances et des pratiques Ă©ducatives est observĂ©e avec une diminution du stress parental. Une amĂ©lioration des compĂ©tences sociales des enfants est Ă©galement constatĂ©e. Le PFHP nâa cependant pas Ă©tĂ© bĂ©nĂ©fique pour une famille dont la situation sâest dĂ©tĂ©riorĂ©e. Conclusion : Ce PFHP est une intervention prometteuse pour rĂ©pondre aux besoins de formation des familles des jeunes enfants avec un TSA et un retard de dĂ©veloppement. Il reste toutefois insuffisant pour rĂ©pondre aux besoins des parents en grande dĂ©tresse. Un manuel de ce PFHP a Ă©tĂ© Ă©laborĂ© afin de le proposer Ă un plus grand nombre de parents sur diffĂ©rents sites francophones pour valider les effets du programme
On the Number of Zeros of Abelian Integrals: A Constructive Solution of the Infinitesimal Hilbert Sixteenth Problem
We prove that the number of limit cycles generated by a small
non-conservative perturbation of a Hamiltonian polynomial vector field on the
plane, is bounded by a double exponential of the degree of the fields. This
solves the long-standing tangential Hilbert 16th problem. The proof uses only
the fact that Abelian integrals of a given degree are horizontal sections of a
regular flat meromorphic connection (Gauss-Manin connection) with a
quasiunipotent monodromy group.Comment: Final revisio
Influence of halloysite nanotubes on physical and mechanical properties of cellulose fibres reinforced vinyl ester composites
Natural fibres are generally added to polymer matrix composites to produce materials with the desirable mechanical properties of higher specific strength and higher specific modulus while at the same time to maintain a low density and low cost. The physical and mechanical properties of polymer composites can be enhanced through the addition of nanofillers such as halloysite nanotubes. This article describes the fabrication of vinyl ester eco-composites and eco-nanocomposites and characterizes these samples in terms of water absorption, mechanical and thermal properties. Weight gain test and Fourier transform infrared analysis indicated that 5% halloysite nanotube addition gave favourable reduction in the water absorption and increased the fibreâmatrix adhesion leading to improved strength properties in the eco-nanocomposites. However, halloysite nanotube addition resulted in reduced toughness but improved thermal stability
The reactivity of linseed and soybean oil with different epoxidation degree towards vinyl acetate and impact of the resulting copolymer on the wood durability
Linseed (LO) and soybean oil (SO) were inâsitu epoxidized with peracetic acid to produce different degree of epoxidized LO and epoxidized SO. For comparison purpose, commercial epoxidized linseed oil (ELOÂź) and epoxidized soybean oil (ESOÂź) were also included in the study. The effect of epoxidation degree on the copolymerization reaction between epoxidized oils and vinyl acetate (VAc) was investigated. Results showed that a copolymer can be formed between VAc and epoxidized LO with high epoxy content, while no reaction occurred between VAc and SO or its epoxidized derivatives. As the most reactive monomer among the studied oils, the epoxidized LO with highest epoxy content (i.e. ELOÂź) was mixed with VAc and then impregnated into the wood using three different ELOÂź/VAc formulations either as solution or as emulsions. After curing, the impact of the resulting copolymer issued from the three tested formulations on the wood durability was evaluated. Results showed that the formulation comprising VAc, ELOÂź, H2O, K2S2O8 and alkaline emulsifier (Formulation 3) can significantly improve woodâs durability against white rot- (Trametes versicolor) and brown rot fungi (Postia placenta and Coniophora puteana). Treated wood of 8% weight percentage gain (WPG) was sufficient to ensure decay resistance against the test fungi with less than 5% mass loss
A New Efficient Authenticated and Key Agreement Scheme for SIP Using Digital Signature Algorithm on Elliptic Curves
Voice over Internet Protocol (VoIP) has been recently one of the more popular applications in Internet technology. It benefits lower cost of equipment, operation, and better integration with data applications than voice communications over telephone networks. However, the voice packets delivered over the Internet are not protected. The session initiation protocol (SIP) is widely used signaling protocol that controls communications on the Internet, typically using hypertext transport protocol (HTTP) digest authentication, which is vulnerable to many forms of attacks. This paper proposes a new secure authentication and key agreement scheme based on Digital Signature Algorithm (DSA) and Elliptic Curve Cryptography (ECC) named (ECDSA). Security analysis demonstrates that the proposed scheme can resist various attacks and it can be applied to authenticate the users with different SIP domains
Ăvolution des styles dâattachement romantique et interpersonnel au cours de lâhospitalisation chez des femmes adultes dĂ©primĂ©es
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