4,065 research outputs found

    Inertial and retardation effects for dislocation interactions

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    A new formulation for the equation of motion of interacting dislocations is derived. From this solution it is shown that additional coupling forces, of kinetic and inertial origin, should be considered in Dislocation Dynamics (DD) simulations at high strain rates. A heuristic modification of this general equation of motion enables one to introduce retardation into inertial and elastic forces, in accordance with a progressive rearrangement of fields through wave propagation. The influence of the corresponding coupling terms and retardation effects are then illustrated in the case of dislocation dipolar interaction and coplanar annihilation. Finally, comparison is made between the modified equation of motion and a precise numerical solution based on the Peierls-Nabarro Galerkin method. Good agreement is found between the Peierls-Nabarro Galerkin method and the EoM including retardation effects for a dipolar interaction. For coplanar annihilation, it is demonstrated that an unexpected mechanism, involving a complex interplay between the core of the dislocations and kinetics energies, allows a renucleation from the completely annihilated dislocations. A description of this phenomenon that could break the most favourable reaction between dislocations is proposed

    LpL^p compression of some HNN extensions

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    Using recent developments on locally compact groups, we are able to obtain quantitative results on embeddings into Lebesgue spaces for a large class of HNN extensions

    Post-traumatic stress symptoms in 223 childhood cancer survivors: incidence, severity and predictive risk factors

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    With modern therapies and supportive care, survival rates of childhood cancer have increased considerably. However, there are long-term psychological sequelae of these treatments that may not manifest until pediatric survivors are into adulthood. The prevalence of post-traumatic stress disorder in young adult survivors of childhood cancer ranges from 6.2 to 22%; associated risk factors are young age at the assessment, female gender, low education level, and some disease-related factors. The aim of this study was to investigate, in adolescent and young adult (AYA) survivors of childhood cancer, the incidence and severity of post-traumatic stress symptoms (PTSSs), and to identify the risk factors and the associated post-traumatic growth (PTG) index. Participants were 223 AYA cancer survivors recruited during follow-up visits in the Oncohematology Clinic of the Department of Child and Woman\u2019s Health, University of Padua. Data were collected from self-report questionnaires on PTSS incidence, PTG mean score, perceived social support, and medical and socio-demographic factors. Ex-patients\u2019 mean age at the assessment was 19.33 years (SD = 3.01, 15\u201325), 123 males and 100 females, with a mean of years off-therapy of 9.64 (SD = 4.17). Most (52.5%) had survived an hematological disorder and 47.5% a solid tumor when they were aged, on average, 8.02 years (SD = 4.40). The main results indicated a moderate presence of clinical ( 659 symptoms: 9.4%) and sub-clinical PTSS (6\u20138 symptoms: 11.2%), with the avoidance criterion most often encountered. Re-experience symptoms and PTG mean score were significantly associated (r = 0.24; p = 0.0001). A hierarchical regression model (R2 = 0.08; F = 1.46; p = 0.05) identified female gender (\u3b2 = 0.16; p = 0.05) and less perceived social support (\u3b2 = -0.43; p = 0.05) as risk factors to developing PTSS. Another hierarchical regression model assessed the possible predictors of the PTG total score (R2 = 0.36; F = 9.1; p = 0.0001), with female gender (\u3b2 = 0.13; p = 0.04), actual age (\u3b2 = 0.52; p = 0.0001), younger age at the diagnosis (\u3b2 = -0.3; p = 0.02), and less years off-therapy (\u3b2 = -0.58; p = 0.0001) impacting on PTG

    Parenté agnatique et par alliance, positions statutaires et circulation des offrandes : le déroulement contemporain d'une cérémonie des morts dans la vallée de la Kouaoua (Nouvelle-Calédonie)

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    Kinship along masculine and wedding lines, statutory position and the circulation of offerings. A contemporary death ceremony in the Kouaoua valley (New Caledonia). Contemporary death ceremonies are built up upon a dual opposition between two groups representing respectively the dead person's paternals and his maternal uncles. Each of the two mainly concerned lignages summons up their own kin along both masculine and wedding lines. Relationship to the dead - whether male or female - in both masculine and wedding lines gives the clue to the various statutory precedences actualized during the different stages of the ceremony, as well as the encompassing classification of the participating groups made during food distribution. Death brings up an inferiority position to the members of the chiefdom organizing the gathering which devolute statutory positions to the various participating groups all the higher as these belong to the dead's maternal uncles or as they are all the more sociologically removed from themselves according to both masculine and wedding lines. The circulation of gifts and counter gifts emphasizes participation rather than actual quantities being exchanged or their balance. As one can judge, these contemporary death ceremonies could be a compromise between different types of precolonial ceremonial gatherings. (Key words : South Pacific ; New Caledonia ; Kouaoua ; death ceremonies ; kinship along masculine and wedding lines ; statutory positions ; circulation of exchanges ; social change.)Pillon Patrick. Parenté agnatique et par alliance, positions statutaires et circulation des offrandes : le déroulement contemporain d'une cérémonie des morts dans la vallée de la Kouaoua (Nouvelle-Calédonie). In: Journal de la Société des océanistes, 100-101, 1995-1-2. pp. 165-190

    Groupements d'élevage mélanésiens et recompositions sociales en Nouvelle-Calédonie

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    Les tendances récentes de l'élevage bovin en milieu mélanésien sont inséparables des profondes transformations qui affectent la société néo-calédonienne depuis une quinzaine d'années. L'accent mis, au plan politique, sur le développement du secteur rural en liaison aux réformes foncières constitue dès lors les modalités des recompositions sociales en tant qu'enjeux; tel est plus particulièrement le cas des compositions des groupements d'élevage dans la mesure où celles-ci renvoient aux alternatives du contrôle foncier. Différents facteurs semblent dès lors orienter les recompositions du secteur rural mélanésien, parmi lesquels les enjeux spécifiques des groupes locaux. (Résumé d'auteur

    Changing Gears, Facing Fears: Leadership in Transition

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    Karen Pillon discusses the challenges of transitioning to a position of management in libraries and how leading people effectively is central to good management

    Figures sahariennes

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    Self\u2010esteem and academic difficulties in preadolescents and adolescents healed from paediatric leukaemia

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    Adolescents with cancer may demonstrate problems in their self\u2010esteem and schooling. This study aims to screen the preadolescents and adolescents more at risk in their self\u2010esteem perception and schooling difficulties post\u2010five years from the end of therapy. Twenty\u2010five paediatric ex\u2010patients healed from leukaemia were recruited at the Haematology\u2010Oncologic Clinic (University of Padua). The mean age of the children was 13.64 years (Standard Deviation (SD)) = 3.08, range = 10\u201319 years), most were treated for acute lymphoblastic leukaemia (ALL) (84%) and relatively equally distributed by gender. They filled in the Multidimensional Self\u2010Esteem Test, while parents completed a questionnaire on their child\u2019s schooling. Global self\u2010esteem was mostly below the 50 percentile (58.5%), especially regarding interpersonal relationships (75%). An independent sample t\u2010test showed significant mean differences on the emotionality scale (t = 2.23; degree of freedom (df) = 24; p = 0.03) and in the bodily experience scale (t = 3.02; df = 24; p = 0.006) with survivors of Acute Myeloid Leukaemia (AML) having lower scores. An Analysis of Variance (ANOVA) showed significant mean differences in the bodily experience scale (F = 12.31; df = 2, p = 0.0001) depending on the survivors\u2019 assigned risk band. The parent reports showed that 43.5% of children had difficulties at school. Childhood AML survivors with a high\u2010risk treatment were more at risk in their self\u2010esteem perceptions. Preventive interventions focusing on self\u2010esteem and scholastic wellbeing are suggested in order to help their return to their normal schedules
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