Full breastfeeding and paediatric cancer

Aim: It has been suggested that there is an inverse association between breastfeeding and the risk of childhood cancer. We investigated the association between full breastfeeding and paediatric cancer (PC) in a case control study in Spain. Methods: Maternal reports of full breastfeeding, collected through personal interviews using the Paediatric Environmental History, were compared among 187 children 6 months of age or older who had PC and 187 age-matched control siblings. Results: The mean duration of full breastfeeding for cases were 8.43 and 11.25 weeks for controls. Cases had been significantly more often bottle-fed than controls (odds ratio (OR) 1.8; 95% confidence interval (CI) 1.1-2.8). Cases were significantly less breastfed for at least 2 months (OR 0.5; 95% CI 0.3-0.8), for at least 4 months (OR 0.5; 95% CI 0.3-0.8), and for 24 weeks or more (OR 0.5; 95% CI 0.2-0.9). Conclusions: Breastfeeding was inversely associated with PC, the protection increasing with the duration of full breastfeeding. Additional research on possible mechanisms of this association may be warranted. Meanwhile, breastfeeding should be encouraged among mothers

Finite element modeling and experimental validation of a HIL test bench for pantographs

[ES] El sector del transport està en contínua evolució cap a un model més sostenible en què el ferrocarril hi juga un paper indispensable. En aquest mitjà de transport, els pantògrafs són una peça clau, ja que són els encarregats de captar el corrent elèctric que circula per la catenària. Previ a la posada en servei, els pantògrafs han de ser homologats i validats mitjançant assajos experimentals en via. Una alternativa emergent a aquests assajos, que de per si són costosos, és la realització d'assajos 'Hardware In the Loop' (HIL) en què el pantògraf és assajat al laboratori excitat mitjançant un motor lineal que simula el comportament dinàmic de la catenària. La primera fase d'aquest treball consisteix en una ampliació i millora d un model d'elements finits del banc d'assajos HIL de pantògrafs que té l'Institut d'Enginyeria Mecànica i Biomecànica (I2MB) de la Universitat Politècnica de València, consistent en modelar més detalladament els elements que formen la biga, així com afegir les parts que no estan modelades i que permetran una representació més fidel a la realitat. Aquest model és validat en una segona fase mitjançant tècniques d anàlisi modal experimental que consisteixen en l excitació del banc i lectura de la resposta del mateix per mitjà d instruments de laboratori, per al posterior tractament amb un ordinador de les dades recollides. Finalment, es proposa un nou disseny per a enrigidir el banc i així poder augmentar el rang de freqüències de realització d'assajos HIL per sobre dels 25 Hz actuals.[EN] The transportation sector is constantly evolving towards a more sustainable model in which railways play an indispensable role. In this means of transport, pantographs play a key role, since they are responsible for capturing the electrical current that circulates through the catenary. Prior to being put into service, the pantographs must be approved and validated through experimental tests on track. An emerging alternative to these tests, which are expensive, is the performance of Hardware In the Loop (HIL) tests in which the pantograph is tested in a laboratory and actuated by a linear motor that simulates the dynamic behaviour of a catenary. The first phase of this work consists of expanding and improving a finite element model of the HIL pantograph test bench owned by the Institute of Mechanical and Biomechanical Engineering (I2MB) of the Universitat Politècnica de València, by modelling in detail the beam elements and by adding the parts which are not currently modelled to make the finite element model look like reality. This model is validated in a second phase using experimental modal analysis techniques that consist of exciting the bench and reading the response by using laboratory instruments, and the subsequent data processing. Finally, a redesign is proposed to stiffen the bench and thus, to be able to increase the range of frequencies for carrying out HIL tests above the current 25 Hz.Ferrís Tortajada, M. (2022). Modelatge mitjançant elements finits i validació experimental d'un banc d'assajos HIL per a pantògrafs. Universitat Politècnica de València. http://hdl.handle.net/10251/185041TFG