Estruturas de conhecimento e sensibilidade ao contexto : o papel da monitorização na reconstrução de crenças

Tese de mestrado, Psicologia (Cognição Social Aplicada), Universidade de Lisboa, Faculdade de Psicologia, 2010As perspectivas clássicas de organização dos estereótipos sempre defenderam que estes são estruturas de conhecimento estáveis e imutáveis. No entanto, investigações recentes têm vindo a demonstrar que existe, uma certa maleabilidade e instabilidade associada aos estereótipos, que se encontra fortemente associada a uma sensibilidade ao contexto, no qual estes são reconstruídos. Assim, ao reconstruírem as suas crenças estereotípicas, os indivíduos incorporam informação presente no contexto, mesmo que esta seja irrelevante para os estereótipos (Santos et al., submetido). Propôs-se que estes efeitos de contaminação contextual poderiam ser o resultado de uma falha da monitorização de crenças, que teria lugar durante a recompilação das crenças, a partir de pistas compósitas, levando assim as pessoas a responderem com base em julgamentos heurísticos derivados da activação momentânea dos conteúdos primados pelo contexto (Santos et al., submetido). Nesse sentido, o principal objectivo do presente estudo foi o de compreender quais são os mecanismos envolvidos na reconstrução de crenças sociais e, em particular, determinar qual o papel da monitorização neste processo, utilizando, para tal, crenças típicas sobre categorias não sociais. Nas experiências propostas por este estudo, optou-se por recorrer a uma manipulação do contexto. Assim nos experimentos, os participantes poderão ser primados com um conceito relevante, irrelevante ou incongruente, relativamente a uma crença típica acerca de uma categoria comum de seres vivos (experiência 1) ou de seres não vivos (experiência 2). Assim, espera-se poder observar que a primação fortuita de atributos irrelevantes e atípicos no contexto tenha uma influência directa na compilação das crenças sobre a categoria em causa, levando a que estes sejam escolhidos, mais frequentemente, como relevantes para descrever a categoria. Os resultados esperados nas várias experiências foram apresentados e discutidos, tendo sido igualmente discutidas as suas implicações empíricas e teóricas.Traditional perspectives on the organization of stereotypes have always defended the notion that these are highly stable and immutable knowledge structures. However, recent research has come to demonstrate that there is a certain malleability and instability associated with stereotypes, which are closely associated with a sensitivity in regard to the context in which they are assembled. Therefore, when assembling their stereotypical beliefs, people incorporate contextual information, even if this information is irrelevant to the stereotype (Santos et al., submitted). It was proposed that the effects of contextual contamination could result from a failure to trigger the belief-monitoring of the output of the compound-cue mechanism during belief assembling. This would result in people answering with resort to heuristic judgments derived from the momentary activation of contextually-primed contents (Santos et al, submitted). Therefore, the main goal of the present study is to understand which mechanisms are involved in the assembling of social beliefs and, in particular, to determine the role of monitoring in this process, through the use of typical beliefs about non-social categories. In the experiments proposed by this study, we opted to do a context manipulation. Thus, in these experiments, participants may be primed with a relevant, irrelevant or incongruous trait regarding typical beliefs about common categories of living (experiment 1) or non-living things (experiment 2). It is expected that the activation of irrelevant and atypical traits, through fortuitous priming prior to the belief assembling, will increase the inclusion of the expressed belief, implying that these will likely be chosen more often to describe the subsequently assessed beliefs about the category. The expected results of both experiments, as well as their empirical and theoretical implications, are presented and discussed

Confirmation bias in acquisition of information based on political affiliation

This paper studies the impact of confirmation bias on the choice between biased sources of political information in a pre-election period. A sample of 204 Portuguese respondents was used, through a survey regarding their political identity and relating it to each one’s choice of information sources, as a voter and as a single decision-maker. Significant differences in behaviour were found according to one’s political identity. Evidence was found for some significant confirmation-seeking behaviour among right-wing participants, but some hypotheses concerning expressive voting and the effects of various factors on confirmation bias weren’t confirmed

Prevalence of diabetes-associated gene variants and its association with blood glucose levels in the Algarve population, Portugal

The global rise in incidence of type 2 (T2D) has been called a pandemic, constituting a major public health concern. Although environmental factors play a substantial role in the etiology of T2D, genetic susceptibility has been established as a key component in T2D risk. Given the absence of studies regarding the prevalence of T2D associated variants in the Portuguese population, our aim was to determine the prevalence of disease-associated variants and determine its relative contribution to this phenotype. For this purpose, we have recruited 221 individuals (93 males and 128 females), between 26-91 years old (mean age 57.1), who were enrolled in the Health Centre of S. Brás de Alportel (Algarve). For each participant, we have measured total glucose levels and collected DNA. In addition, each participant has answered an exhaustive questionnaire including socio-demographic information, health history and lifestyle. We have selected and analysed three of the most significant loci previously reported to be associated with T2D in Caucasian populations (TCF7L2 rs7903146, PARPG rs1801282 and FTO rs9939609) and performed an association analysis between glucose levels in this population and the selected gene variants. The mean total population glucose level was 103.85±35.3 g/dl. We found a significant difference in the mean glucose levels between males (mean = 111.5±51.3 g/dl) and females (mean = 98.4±17.6 g/dl) (Mann-Whitney test P < 0.001). The relative allele frequencies of the genotyped variants have been established. Genotype distribution for all investigated SNPs was in Hardy-Weinberg equilibrium. We found a marginal association between glucose levels and genotypes at the TCF7L2 locus (Mann-Whitney test P = 0.045) in females but not in males, with carriers of the T allele displaying higher levels of blood glucose than homozygous for the A allele. This difference is also observed in males, although not reaching significance. No association was found between glucose levels and the other genotyped variants. These results suggest that the pathophysiology of the disease may be different between males and females, or that environmental factors are influencing this trait in males. We are currently investigating the later hypothesis by increasing our sample size and by analysing lifestyle information provided by the participants in order to evaluate gene-environment interactions influencing glucose levels in the Portuguese population.The pilot study of the Portuguese Component of the European Health Examination Survey (EHES) project has received funding from the European Commission/DG Sanco (Agreement number: 20092301 – EHES JA – EAHC). This study has also received funding from the Portuguese Foundation for Science and Technology (FCT) (Project Reference: PTDC/SAU-ESA/101743/2008)

Validação e estimativa da incerteza de método para análise de licopeno e β-caroteno em polpa de tomate por cromatografia líquida de alta eficiência

A method to quantify lycopene and β-carotene in freeze dried tomato pulp by high performance liquid chromatography (HLPC) was validated according to the criteria of selectivity, sensitivity, precision and accuracy, and uncertainty estimation of measurement was determined with data obtained in the validation. The validated method presented is selective in terms of analysis, and it had a good precision and accuracy. Detection limit for lycopene and β-carotene was 4.2 and 0.23 mg 100 g-1, respectively. The estimation of expanded uncertainty (K = 2) for lycopene was 104 ± 21 mg 100 g-1 and for β-carotene was 6.4 ± 1.5 mg 100 g-1

Prevalence of alpha-1 antitrypsin deficiency and hereditary hemochromatosis gene mutations in Algarve, Portugal

Alpha-1 antitrypsin (AAT) deficiency and hereditary hemochromatosis (HH) are two of the most fatal genetic disorders in adult life, affecting million individuals worldwide. They are often under-diagnosed conditions and diagnosis is only made when the patient is already in the advanced stages of damage. AAT deficiency results from mutations in one highly pleiomorphic gene located on chromosome 14, SERPINA 1, being Z and S mutations the most relevant clinically. These mutations will lead to an AAT deficit that compromises the lungs protection, originating emphysema, chronic bronchitis, asthma or even chronic obstructive pulmonary disease (COPD) and it is also strongly associated with various liver diseases. On the other hand, C282Y and H63D mutations in the HFE gene, located on chromosome 6, are reported to be mostly responsible for the iron accumulation in HH disorder, leading to severe damage in different organs. Disease manifestations include cirrhosis, hepatic fibrosis, diabetes mellitus, arthropathy and hepatocarcinoma. Given the insufficient population-based information about the prevalence of these gene variants in the Portuguese population, the aim of this study was to assess their frequency in a representative sample from São Brás de Alportel, in the South of Portugal. To achieve our goal, we have genotyped a total of 208 adult subjects, including 118 females and 90 males (mean age: 58 years, range: 26-91). Regarding AAT deficiency, we found 4,3% MZ, 0,5% SS and 15,4% MS genotypes. The calculated frequency for the Z allele was 2,2% (95% CI: 0-11,7%) and for the S allele was 8,2% (95% CI: 0-17,4%). About HH, we found 1,4% C282Y/H63D, 2,4% H63D/H63D, 5,8% C282Y/N and 23,6% H63D/N genotypes. Frequencies of C282Y and H63D alleles were 3,6% (95% CI: 0-13%) and 14,9% (95% CI: 6-23,8%), respectively. The observed allele frequencies were in Hardy-Weinberg Equilibrium and no association was found with related diseases likely due to the smaller sample available. Our findings show the highest prevalence of Z allele from SERPINA1 gene found, when compared to other populations. The remaining findings are in agreement with previously published studies. Future studies involving a larger sample size will be necessary to evaluate the penetrance of the studied gene mutations and to assess gene-environment interactions that influence disease risk, contributing to reduce the burden of these diseases which can have a great public health impact.The pilot study of the Portuguese Component of the European Health Examination Survey (EHES) project has received funding from the European Commission/DG Sanco (Agreement number: 20092301 – EHES JA – EAHC). This study has also received funding from the Portuguese Foundation for Science and Technology (FCT) (Project Reference: PTDC/SAU-ESA/101743/2008)

Genetic variation at the IFITM3 and Influenza A(H1N1)pdm09 infection severity in the Portuguese population

Interferon-inducible transmembrane protein (IFITM3) inhibits the entry of viruses to the host cell, mediating resistance to influenza infection. It has been demonstrated that a genetic variation in the IFITM3 gene (rs12252) alters a splice-site, originating a protein with reduced activity. In this context, our aim was to determine if the C allele of the IFITM3 rs12252 polymorphism is associated with influenza infection or hospitalizations related to Influenza A(H1)pdm09 in the Portuguese population. To achieve our goal, a case-control study design was developed using the nasal swabs collected during the 2009 pandemic, on the context of the National Influenza Surveillance Program. Non-hospitalized influenza cases were defined as patients with influenza like illness (ILI) who tested positive for influenza A(H1)pdm09 and did not require hospitalization. Hospitalized-influenza cases were defined as ILI patients who tested positive for A(H1)pdm09 infection and who were hospitalized. For these cases groups two types of controls were selected: non-hospitalized ILI cases negative for A(H1)pdm09 and hospitalized ILI patients negative for A(H1)pdm09 infection. We have therefore selected 212 non-hospitalized influenza cases, 96 hospitalized influenza cases, 403 non-hospitalized negative controls and 198 hospitalized negative controls. We found that hospitalized negative controls had the highest frequency of allele C carriers (22.5%) and the lowest frequency was found among the non-hospitalized negative controls (11.11%). No association was found between testing positive for A(H1)pdm09 infection (susceptibility to infection) and the C allele of rs12252. We have also found that the risk of being hospitalized (independently of infection status) for the allele C carriers is the highest, after adjustment for age and gender, (OR: 1.59 (95% CI: 1.05-2.43). Our results suggest that the allele C of the IFITM3 rs122252 polymorphism was associated with respiratory disease hospitalizations but not specifically associated with the infection by Influenza A(H1N1)pdm09

Genetic variation at the CY2C19 gene associated with Metabolic Syndrome susceptibility in a South Portuguese population

Metabolic syndrome (MetS) is a cluster of conditions — increased blood pressure, high blood glucose level, excess body fat around the waist and abnormal cholesterol levels — that occur together, increasing the risk of heart disease, stroke and diabetes. In Portugal, the MetS prevalence is estimated to be 27,5% with regional variations, being highest in the Alentejo (30,99%) and lowest in the Algarve (24,42%), constituting a public health problem. Although for clinical settings, a binary definition of MetS enabling a yes or no diagnosis is useful, it is clear that dichotomizing a continuous outcome variable reduces the statistical power of the MetS association studies. Therefore, the aim of the present study is to identify genetic risk factors involved in MetS etiology, using a continuous MetS score. To achieve our goal, a principal component analysis was performed to compute a score using the six normalized risk factors for MetS (waist circumference, diastolic and systolic blood pressure, glucose, triglycerides and HDL blood levels), with a higher MetS score indicating a less favorable MetS profile. After calculating this score, an association study was performed using 37 SNPs in candidate genes involved in MetS related diseases. A total of 206 subjects, including 119 women and 87 men (mean age: 56,31± 16,37 years, range: 26-91 years) were included in this analysis. We found 4 SNPs significantly associated with higher MetS scores (rs4244285 (CYP2C19), rs279871 (GABRA2), rs1647 (NPY) and rs1142345(TPMT)). P-values are 4,36x10-4, 1,3x10-2, 1,7x10-2 and 9,76x10-3 respectively. After correcting for multiple testing only rs4244285 (CYP2C19) remains significant (p=0,016). In addition, we have performed a multiple regression analysis considering the CYP2C19 genotype as the independent variable, adjusted for age. The resulting model explains 17% of the MetS score variance. After adding the remaining SNP genotypes that do not survive the multiple testing correction, the same model is able to explain 23,1% of the score. Our findings support the evidence of an association between CYP2C19 rs4244285 gene polymorphism and the MetS score, emphasizing the importance of lipid metabolism, thought cytochrome P450 enzymes, in the MetS etiology. However, further studies will be necessary to replicate these findings in different populations as well as functional studies to clarify the role of this variant in the etiology of MetS.The pilot study of the Portuguese Component of the European Health Examination Survey (EHES) project has received funding from the European Commission/DG Sanco (Agreement number: 20092301 – EHES JA – EAHC). This study has also received funding from the Portuguese Foundation for Science and Technology (FCT) (Project Reference: PTDC/SAU-ESA/101743/2008)