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Brilhante M.F.,University of The Azores | Brilhante M.F.,University of Lisbon | Pestana D.,University of Lisbon | Pestana D.,Institute Investigacao Cientifica Bento da Rocha Cabral | And 2 more authors.
AIP Conference Proceedings | Year: 2015

The family Xm, m ε [-2, 2], whose density is obtained tilting the uniform density using the pole (0.5, 1) has as extreme cases the Beta(1, 2) density, corresponding to m=-2, and the Beta(2, 1) density, corresponding to m=2. For intermediate m, the density mixes the uniform density (m=0) with one of the extreme cases. It is therefore an appropriate model for reported p-values when the best, or worst, of two replica is recorded whenever the result of the experiment is unexpected. Estimation of the mixing parameter is discussed. © 2015 AIP Publishing LLC. Source

Pestana D.,University of Lisbon | Pestana D.,Institute Investigacao Cientifica Bento da Rocha Cabral
Acta Medica Portuguesa | Year: 2013

Statistics is a privileged tool in building knowledge from information, since the purpose is to extract from a sample limited information conclusions to the whole population. The pervasive use of statistical software (that always provides an answer, the question being adequate or not), and the absence of statistics to confer a scientific flavour to so much bad science, has had a pernicious effect on some disbelief on statistical research. Would Lord Rutherford be alive today, it is almost certain that he would not condemn the use of statistics in research, as he did in the dawn of the 20th century. But he would indeed urge everyone to use statistics quantum satis, since to use bad data, too many data, and statistics to enquire on irrelevant questions, is a source of bad science, namely because with too many data we can establish statistical significance of irrelevant results. This is an important point that addicts of evidence based medicine should be aware of, since the meta analysis of two many data will inevitably establish senseless results. © Ordem dos Médicos 2013. Source

Brilhante M.F.,University of The Azores | Brilhante M.F.,University of Lisbon | Pestana D.,CEAUL | Pestana D.,Institute Investigacao Cientifica Bento da Rocha Cabral
AIP Conference Proceedings | Year: 2015

The BetaBoop(p, q, P, Q), p, q, P, Q > 0, family of random variables includes as special cases Beta(p, q) random variables, which are known to be quite versatile in modeling different randomness patterns. Some results of the multiplicative algebra of BetaBoop random variables are commented in the light of uniform order statistics. Products and products of powers and of random powers of independent standard uniforms are also investigated, namely when the exponent is either uniform or the maximum of an uniform random sample, or its probability density function is a mixture of the uniform density and the density of an extreme of two independent uniform random variables. © 2015 AIP Publishing LLC. Source

Castaldo S.A.,University of Lisbon | Castaldo S.A.,Institute Medicina Molecular | da Silva A.P.,University of Lisbon | Matos A.,University of Lisbon | And 8 more authors.
Tumor Biology | Year: 2015

Human papillomavirus (HPV) infection is necessary but not a sufficient cause for the development of invasive cervical cancer (ICC). Epithelial tissues, target for HPV, are exposed to reactive oxygen species (ROS) associated with tumor initiation and progression. The NADPH oxidase (NOX) and catalase (CAT) are involved in hydrogen peroxide (H2O2) production and inactivation, respectively. P22phox is the NOX subunit encoded by the CYBA gene that has a functional polymorphism (C-242T). This protein is involved in the regulation of electron transfer to oxygen. CAT is a hemic enzyme that plays a role in regulating H2O2 concentration, with a functional polymorphism (C-262T) in its gene. We evaluated CYBA C-242T and CAT C262T genetic polymorphisms and their interaction in 132 women with ICC. We found that CYBA C-242T and CAT C262T genotype frequencies were significantly different between ICC and controls (χ2 test, p = 0.017 and p = 0.009, respectively). Women with the C/T CYBA-242 genotype had a lower risk for ICC development (odds ratio (OR) = 0.515, 95 % confidence interval (CI) 0.291–0.914, p = 0.023) whereas T/T CAT-262 genotype carriers present an increased risk for ICC (OR = 3.034, 95 % CI 1.462–6.298, p = 0.003). Women with C/C genotype for CYBA and T/T genotype for CAT had an increased risk to develop ICC comparing with the interaction of the other possible genotypes of both genes (OR = 3.952, 95 % CI 1.075–14.521, p = 0.032). The CYBA C-242T and CAT C-262T genetic polymorphisms and their epistatic interactions can be associated with ICC through mechanisms related with the role of ROS in cell proliferation and apoptosis. © 2014, International Society of Oncology and BioMarkers (ISOBM). Source

Matos A.,University of Lisbon | Matos A.,Institute Investigacao Cientifica Bento da Rocha Cabral | Castelao C.,University of Lisbon | Pereira Da Silva A.,University of Lisbon | And 6 more authors.
Oxidative Medicine and Cellular Longevity | Year: 2016

There is a clear association between the excessive and cumulative exposure to estrogens and the development of cancer in hormone-sensitive tissues, such as the cervix. We studied the association of CYP1A1 M1 (rs4646903) and COMT (rs4680) polymorphisms in 130 cervical cancer cases (c-cancer) and 179 controls. The CYP1A1 TT genotype was associated with a lower risk for c-cancer (OR = 0.39, p=0.002). The allele C of CYP1A1 was a risk for c-cancer (OR = 2.29, p=0.002). Women with COMT LL genotype had a higher risk of developing c-cancer (OR = 4.83, p<0.001). For the interaction of the CYP1A1&COMT, we observed that TC&HL genotypes had a greater risk for c-cancer (OR = 6.07, p=0.006) and TT&HL genotypes had a protection effect (OR = 0.24, p<0.001). The CYP1A1 TT and COMT LL genotypes had higher estradiol levels in c-cancer (p<0.001 and p=0.037, resp.). C-cancer is associated with less production of 2-methoxy-estradiol resultant of functional polymorphisms of CYP1A1 and COMT, separately. CYP1A1 and COMT work in a metabolic sequence and their interaction could lead to an alternative pathway of estrogen metabolism with production of 16-OH-estrone that is more proliferative. © 2016 Andreia Matos et al. Source

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