CMA - Centro de Matemática e Aplicações da UBI
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CMA, Centre of Mathematics and Applications, is a research unit in Mathematics and Applications, hosted by University of Beira Interior (UBI). UBI provides the requested facilities, budget management, computing support and institutional framework to wards CMA’s activities.
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Browsing CMA - Centro de Matemática e Aplicações da UBI by Subject "Adolescent"
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- Bilateral theta-burst magnetic stimulation influence on event-related brain potentialsPublication . Pinto, Nuno; Duarte, Marta; Gonçalves, Helena; Silva, Ricardo; Gama, Jorge; Patto, Maria Da Assunção VazTheta-burst stimulation (TBS) can be a non-invasive technique to modulate cognitive functions, with promising therapeutic potential, but with some contradictory results. Event related potentials are used as a marker of brain deterioration and can be used to evaluate TBS-related cognitive performance, but its use remains scant. This study aimed to study bilateral inhibitory and excitatory TBS effects upon neurocognitive performance of young healthy volunteers, using the auditory P300' results. Using a double-blind sham-controlled study, 51 healthy volunteers were randomly assigned to five different groups, two submitted to either excitatory (iTBS) or inhibitory (cTBS) stimulation over the left dorsolateral pre-frontal cortex (DLPFC), two other actively stimulated the right DLPFC and finally a sham stimulation group. An oddball based auditory P300 was performed just before a single session of iTBS, cTBS or sham stimulation and repeated immediately after. P300 mean latency comparison between the pre- and post-TBS stimulation stages revealed significantly faster post stimulation latencies only when iTBS was performed on the left hemisphere (p = 0.003). Right and left hemisphere cTBS significantly delayed P300 latency (right p = 0.026; left p = 0.000). Multiple comparisons for N200 showed slower latencies after iTBS over the right hemisphere. No significant difference was found in amplitude variation. TBS appears to effectively influence neural networking involved in P300 formation, but effects seem distinct for iTBS vs cTBS and for the right or the left hemisphere. P300 evoked potentials can be an effective and practical tool to evaluate transcranial magnetic stimulation related outcomes.
- Parents’ educational level and second-hand tobacco smoke exposure at home in a sample of Portuguese childrenPublication . Vitória, Paulo; Nunes, Célia; Precioso, J.Second-hand tobacco smoke (SHS) exposure is a major and entirely avoidable health risk for children's health, well-being and development. The main objective of the current study was to investigate the association between parents' educational level and children's SHS home exposure. A self-administered questionnaire was conducted within a sample of 949 students in 4th grade (mean age 9.56±0.75, 53.4% male). The sample was randomly selected from all schools located at Lisbon District, Portugal. The current study confirmed that Portuguese children are exposed to unacceptable high levels of SHS at home, mainly by their parents' smoke. Prevalence of smokers was higher amongst parents with low educational level. Children of parents with low educational level were more likely to suffer SHS exposure at home. These results confirmed the social inequalities associated with smoking, support the relevance of more research on this subject and stress the need for more interventions to control this problem. Some interventions should be specifically aimed at less educated parents, particularly at less educated mothers.
- The relative age effect among elite youth competitive swimmersPublication . Costa, Aldo M.; Marques, Mário C; Louro, Hugo; Ferreira, Sandra S.; Marinho, DanielThe aim of this study was to analyse the relative age effect (RAE) in competitive swimming. The best 50 Portuguese swimmers (12- to 18-year-olds) for the main individual swimming pool events of both genders were considered. Analysis was conducted on 7813 swimming event participants, taking account of respective swimmer birth dates and the Fédération Internationale de Natation points gained. Differences in the distribution of birth dates by quarter year were determined using the Chi-square. A one-way analysis of variance ANOVA was used to test for differences measured in points between individuals by quarterly birth year intervals. A two-way analysis of variance ANOVA was also conducted to test the interaction between gender and seasonal birth date with regard to performance. The results show an inequitable distribution (p<0.01) of birth dates by quarter for almost all age groups and both genders. However, the distribution of birth dates by quarter for each considered swim event shows that RAE seems to exist only for 12-year-old females and 12- to 15-year-old males. Analysing mean swimming performance, post-hoc results (p<0.01) show no consistency in RAE. Higher performance occurs among older swimmers only in 100 m butterfly (female 1998, 1st≠2nd quarter, p=0.003). The results also show no interaction between gender and seasonal birth date (p<0.01). Findings of this study show that a higher number of swimmers, particular males, are born in the first two quarters of the year, although there is mostly no effect of seasonal birth date on performance differences within the top 50 swimmers.