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

Dinâmica da matéria orgânica no ambiente.

bitstream/item/32409/1/documento-105.pd

Métodos de fracionamento e caracterização da matéria orgânica do solo.

bitstream/item/32410/1/documento-106.pd

Efeito estufa: potencialidades e contribuições da agricultura.

bitstream/item/32413/1/documento-109.pd

The developmental pathways of preschool children with acute lymphoblastic leukemia: communicative and social sequelae one year after treatment

Early childhood is considered to be a period of rapid development, with the acquisition of abilities predicting future positive school competences. Motor, cognitive, and social diculties related to cancer therapies heavily impact the development of children with cancer. This study focused on two main aims: To assess the developmental pathways of preschool children with acute lymphoblastic leukemia one year post-treatment and to compare these abilities both with those of a control group of healthy peers and with Italian norms. Forty-four children and their families, recruited through the Hematology-Oncologic Clinic of the Department of Child andWoman Health (University of Padua), agreed to participate in this study. The children\u2019s mean age was 4.52 years (SD = 0.94, range = 2.5\u20136 years), equally distributed by gender, all diagnosed with acute lymphoblastic leukemia. Matched healthy peers were recruited through pediatricians\u2019 ambulatories. Each family was interviewed adopting the Vineland adaptive behavior scales. Paired sampleWilcoxon tests revealed that children were reported to have significantly more developmental diculties than their healthy peers. When compared with Italian norms, they scored particularly low in verbal competence, social, and coping skills. No significant association was found between treatment variables and developmental abilities. These findings suggest that the creation of specialized interventions, both for parents and children, may fill the possible delays in children\u2019s development probably due to stress, lack of adequate stimulation, or dicult adaptation

Health-related quality of life in AYA cancer survivors who underwent HSCT compared with healthy peers

This\ue002study\ue002was\ue002aimed\ue002at\ue002comparing\ue002adolescent\ue002and\ue002young\ue002adult\ue002(AYA)\ue002Hematopoietic\ue002 Stem Cell Transplantation (HSCT) paediatric cancer survivors and a control group of healthy peers in terms of Health- Related Quality of Life (HRQOL) and frequency of posttraumatic\ue002stress\ue002symptoms\ue002(PTSS).\ue002The\ue002participants\ue002were\ue00232\ue002AYA\ue002HSCT\ue002survi- vors and 28 matched healthy peers. The survivors were, on average, 19.4 years old (SD = 3.8), with an average age of 8.1 years (SD = 4.3) at diagnosis, and with a mean time, since treatment was completed, of 8.5 years (SD = 3.2). The majority of survi- vors (78.1%) did not show clinical PTSS, with intrusion symptoms most frequently reported in those who had undergone autologous HSCT (F = 3.3; df = 2; p = 0.05) and relapse presence in their treatment associated with more PTSS avoidance symptoms (r = 0.4; p\ue002=\ue0020.002).\ue002Women\ue002reported\ue002more\ue002problems\ue002in\ue002the\ue002SF-\ue00236\ue002pain\ue002scale\ue002(t = 2.1; df = 31; p\ue002=\ue0020.04)\ue002than\ue002men.\ue002Additionally,\ue00287.5%\ue002of\ue002survivors\ue002fell\ue002below\ue002the\ue00225th\ue002per- centile\ue002in\ue002the\ue002SF-\ue00236\ue002general\ue002well-\ue002being\ue002scale,\ue002and\ue00270.8%\ue002had\ue002the\ue002same\ue002trend\ue002for\ue002the\ue002 SF-\ue00236\ue002fatigue\ue002scale.\ue002Survivors\ue002reported\ue002better\ue002emotional\ue002well-\ue002being\ue002(t\ue002=\ue0022.6,\ue002df = 27, p = 0.01) and fewer limitations than their healthy peers (t = 2.5, df = 27, p = 0.02), while they perceived a lower life satisfaction referring to the past (t\ue002=\ue002 122.8,\ue002df = 27, p = 0.009)

Equation of motion for dislocations with inertial effects

An approximate equation of motion is proposed for screw and edge dislocations, which accounts for retardation and for relativistic effects in the subsonic range. Good quantitative agreement is found, in accelerated or in decelerated regimes, with numerical results of a more fundamental nature.Comment: 6 pages, 4 figures, LaTe