Inertial and retardation effects for dislocation interactions

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

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

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

LpL^p compression of some HNN extensions

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

Integração é a chave para o sucesso do azeite oliva brasileiro.

bitstream/item/123649/1/digitalizar0024.pd

Groupements d'élevage autochtones dans le Pacifique Sud : trois études de cas : Nouvelle-Zélande, Nouvelle-Calédonie, Papouasie-Nouvelle Guinée

De nombreux pays du Pacifique Sud ont connu durant les dernières décennies un développement rapide de l'élevage bovin dont l'une des formes les plus répandues devient le groupement d'élevage. En comparant les groupements d'élevage autochtones dans trois pays de la région aux situations fortement contrastées, la présente étude met en relief un certain nombre de convergences. Les groupements d'élevage autochtones correspondent ainsi moins à une reconduction culturelle de modèles d'organisation précoloniale qu'à une situation marquée par l'accroissement de la pression foncière, l'intervention de l'Etat en secteur rural, ainsi que par l'émergence et la consolidation de différentes catégories sociales. Des catégories sociales extérieures à la production agricole sont notamment aptes à jouer un rôle important dans la formation des groupements. Les divergences entre les trois pays relèvent par contre de l'importance économique de ceux-ci et de la place qu'ils occupent au sein de l'économie mondiale. Mais elles relèvent plus particulièrement d'une histoire propre où les équilibres politiques et démographiques entre les populations autochtones et les populations européennnes amenées par la colonisation sont centraux. (Résumé d'auteur

Motor skill delays in pre-school children with leukemia one year after treatment: Hematopoietic stem cell transplantation therapy as an important risk factor

CNS-directed therapies for the treatment of leukemia can adversely affect the acquisition of new skills, such as reading/writing and math. Two years after the end of treatments, children show gross and fine motor skill delays that may persist even when patients are considered healed. The goal of the present study was to assess motor skills difficulties in pre-school children with leukemia one year after treatment. Particular attention has been paid to those patients who had undergone Hematopoietic Stem Cell Transplantation (HSCT) and to the relationship between motor delays and age bands. Participants were 60 children (median age of 5; inter quartile range: 3.07-5.76), including 31 females and 29 males, 91.7% of them were affected by acute lymphoblastic leukemia (ALL), and 8.3% by acute myeloid leukemia (AML). Five children had undergone HCST. Parents were interviewed by Vineland Adaptive Behavior Scales (VABS) on children\u2019s motor skills and filled in the Italian Temperament Questionnaire (QUIT). VABS\u2019s total scores were converted into equivalent mental age scores (EMA). A score difference of at least three months between current age and equivalent mental age was considered a developmental delay. Non-parametric analyses were run to understand if HSCT treatment and a specific age band influence children\u2019s motor skills. Significant delays were found in global motor skills (56.7%) as well as in fine and gross motor domains. Mann Whitney U tests showed that children with HSCT were reported to have lower gross motor mean ranks (U = 62; p=0.004; Mean rank =15.40) than peers without HSCT (Mean rank = 31.87) and lower mean rank values on motor temperament scale (U = 9; p = 0.003; HSCT Mean rank = 4.75 versus no HSCT Mean rank = 27.81). Kruskal Wallis\u2019 tests identified the high risk treatment showing that HSCT experience negatively impacted the motor skills and temperamental motor activity of pre-school children one year after the diagnosis of leukemia