Wear and surface residual stress evolution on twin-disc tests of rail/wheel steels

Twin disc tribological tests were performed in wheel and rail materials, with specimens taken from a Spanish AVE train wheel and a UIC60 rail, in a program intended to characterize their contact fatigue behavior. The X-ray diffraction technique was used to characterize the residual stress distribution at the initial and damaged stages, as well as in intermediate stages, since existing residual stresses in the surface layers of the railways steels and its evolution during contact loading can have a major influence on crack initiation and propagation

Stationary solutions for the parity-even sector of the CPT-even and Lorentz-covariance-violating term of the standard model extension

In this work, we focus on some properties of the parity-even sector of the CPT-even electrodynamics of the standard model extension. We analyze how the six non-birefringent terms belonging to this sector modify the static and stationary classical solutions of the usual Maxwell theory. We observe that the parity-even terms do not couple the electric and magnetic sectors (at least in the stationary regime). The Green's method is used to obtain solutions for the field strengths E and B at first order in the Lorentz- covariance-violating parameters. Explicit solutions are attained for point-like and spatially extended sources, for which a dipolar expansion is achieved. Finally, it is presented an Earth-based experiment that can lead (in principle) to an upper bound on the anisotropic coefficients as stringent as $(\widetilde{\kappa}_{e-}) ^{ij}<2.9\times10^{-20}.$Comment: 8 pages, revtex style, revised published version, to appear in EPJC (2009

Emotional, hyperactivity and inattention problems in adolescents with immunocompromising chronic diseases during the COVID-19 pandemic

Objective: To assess factors associated with emotional changes and Hyperactivity/Inattention (HI) motivated by COVID-19 quarantine in adolescents with immunocompromising diseases. Methods: A cross-sectional study included&nbsp;343&nbsp;adolescents with immunocompromising diseases and 108&nbsp;healthy adolescents. Online questionnaires were answered including socio-demographic data and self-rated healthcare routine during COVID-19 quarantine and validated surveys: Strengths and Difficulties Questionnaire (SDQ), Pittsburgh Sleep Quality Index (PSQI), Pediatric Quality of Life Inventory 4.0 (PedsQL4.0). Results: The frequencies of abnormal emotional SDQ scores from adolescents with chronic diseases were similar to those of healthy subjects (110/343&nbsp;[32%] vs.&nbsp;38/108 [35%], p&nbsp;=&nbsp;0.548), as well as abnormal hyperactivity/inattention SDQ scores (79/343 [23%] vs.&nbsp;29/108 [27%], p&nbsp;=&nbsp;0.417). Logistic regression analysis of independent variables associated with abnormal emotional scores from adolescents with chronic diseases showed: female sex (Odds Ratio [OR&nbsp;=&nbsp;3.76]; 95%&nbsp;Confidence Interval (95%&nbsp;CI) 2.00‒7.05; p &lt; 0.001), poor sleep quality (OR&nbsp;=&nbsp;2.05; 95%&nbsp;CI&nbsp;1.08‒3.88; p&nbsp;=&nbsp;0.028) and intrafamilial violence during pandemic (OR&nbsp;=&nbsp;2.17; 95%&nbsp;CI&nbsp;1.12‒4.19; p&nbsp;=&nbsp;0.021) as independently associated with abnormal emotional scores, whereas total PedsQL score was inversely associated with abnormal emotional scores (OR&nbsp;=&nbsp;0.95; 95%&nbsp;CI&nbsp;0.93‒0.96; p &lt; 0.0001). Logistic regression analysis associated with abnormal HI scores from patients evidenced that total PedsQL score (OR&nbsp;=&nbsp;0.97; 95%&nbsp;CI&nbsp;0.95‒0.99; p&nbsp;=&nbsp;0.010], changes in medical appointments during the pandemic (OR&nbsp;=&nbsp;0.39; 95%&nbsp;CI&nbsp;0.19-0.79; p&nbsp;=&nbsp;0.021), and reliable COVID-19 information (OR&nbsp;=&nbsp;0.35; 95%&nbsp;CI&nbsp;0.16‒0.77; p&nbsp;=&nbsp;0.026) remained inversely associated with abnormal HI scores. Conclusion: The present study showed emotional and HI disturbances in adolescents with chronic immunosuppressive diseases during the COVID-19 pandemic. It reinforces the need to promptly implement a longitudinal program to protect the mental health of adolescents with and without chronic illnesses during future pandemics

Adubação nitrogenada de sorgo granífero consorciado com capim em sistema de plantio direto

O objetivo deste trabalho foi avaliar o efeito do manejo da adubação nitrogenada sobre a cultura do sorgo granífero, cultivado solteiro e em consócio com capim-marandu e capim-mombaça, e determinar a produtividade de matéria seca das forrageiras, nos anos agrícolas 2003/2004 e 2004/2005, em plantio direto. Foi utilizado o delineamento experimental em blocos ao acaso, em arranjo fatorial 3x5, com quatro repetições. Os tratamentos consistiram de três sistemas de cultivo de sorgo granífero (solteiro e consorciado com capim-marandu ou capim-mombaça, na linha de semeadura) e cinco manejos de adubação nitrogenada: 30-70; 70-30; 50-50; 100-0; e 0-100 kg ha-1 de N, quantidades aplicadas na semeadura e na cobertura, respectivamente. O cultivo consorciado não afetou a nutrição nem a produtividade de grãos de sorgo. Apenas no primeiro ano de cultivo, o parcelamento 50-50 kg ha-1 de N proporcionou maior produtividade de grãos. O manejo da palhada interferiu no estabelecimento do sorgo no segundo ano de cultivo, e diminuiu a produtividade de grãos. As maiores doses de N aplicadas em cobertura elevaram a produtividade de matéria seca do capim-marandu e, as aplicadas em semeadura, a elevaram no capim-mombaça

Human toxocariasis: contribution by Brazilian researchers

In the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of São Paulo (IMT)