Forecasting human entrances at a commercial store using facial recognition data

Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação

Silent citizens: on silence and silencing in journalism

Constructivist approaches to journalism, which have dominated the field for most of the second half of the 20th century, underline how selection and ranking processes produce representations and interpretations of social reality. Theoretical perspectives such as agenda-setting or framing have been pointing to the ways production of news messages are shaped and issues are defined. Research inspired by these contributions does however seem to keep in an area of relative shade not so much what is said and published but what is not selected: the unsaid, the withheld, the untold of journalism. The reality that remains in silence, for not being noticed or for being silenced, is the reverse of the coin of what is made visible. In this paper, it is suggested that this situation opens up the debate to a relatively unknown continent, which could contribute to the larger discussion on the current crisis in journalism. It is our contention that ‘the untold’ might be at the confluence of different levels: the journalistic agenda-setting by news sources; the deterioration of working conditions of journalists, compromising the investigation; and the social capital asymmetries from important segments of the population, hampering the public word (speech?) and the right to communicate. In order to build a comprehensive picture of the potentialities and contradictions of journalism from the unsaid side, we would put forward the outline of a typology of journalism's silences, with particular emphasis on some aspects of "discursive discrimination" (Boréus, 2006), on the one hand, and on citizen silence in the process of journalistic production, on the other hand.

O livro na revista: como revistas semanais brasileiras e portuguesas abordam livros e literatura

Dissertação de mestrado em Comunicação, Arte e Cultura

Food safety in wine: removal of ochratoxin A in contaminated white wine using commercial fining agents

The presence of mycotoxins in foodstuff is a matter of concern for food safety. Mycotoxins are toxic secondary metabolites produced by certain molds, being ochratoxin A (OTA) one of the most relevant. Wines can also be contaminated with these toxicants. Several authors have demonstrated the presence of mycotoxins in wine, especially ochratoxin A (OTA) [1]. Its chemical structure is a dihydro-isocoumarin connected at the 7-carboxy group to a molecule of L--phenylalanine via an amide bond. As these toxicants can never be completely removed from the food chain, many countries have defined levels in food in order to attend health concerns. OTA contamination of wines might be a risk to consumer health, thus requiring treatments to achieve acceptable standards for human consumption [2]. The maximum acceptable level of OTA in wines is 2.0 g/kg according to the Commission regulation No. 1881/2006 [3]. Therefore, the aim of this work was to reduce OTA to safer levels using different fining agents, as well as their impact on white wine physicochemical characteristics. To evaluate their efficiency, 11 commercial fining agents (mineral, synthetic, animal and vegetable proteins) were used to get new approaches on OTA removal from white wine. Trials (including a control without addition of a fining agent) were performed in white wine artificially supplemented with OTA (10 µg/L). OTA analysis were performed after wine fining. Wine was centrifuged at 4000 rpm for 10 min and 1 mL of the supernatant was collected and added of an equal volume of acetonitrile/methanol/acetic acid (78:20:2 v/v/v). Also, the solid fractions obtained after fining, were centrifuged (4000 rpm, 15 min), the resulting supernatant discarded, and the pellet extracted with 1 mL of the above solution and 1 mL of H2O. OTA analysis was performed by HPLC with fluorescence detection according to Abrunhosa and Venâncio [4]. The most effective fining agent in removing OTA (80%) from white wine was a commercial formulation that contains gelatine, bentonite and activated carbon. Removals between 10-30% were obtained with potassium caseinate, yeast cell walls and pea protein. With bentonites, carboxymethylcellulose, polyvinylpolypyrrolidone and chitosan no considerable OTA removal was verified. Following, the effectiveness of seven commercial activated carbons was also evaluated and compared with the commercial formulation that contains gelatine, bentonite and activated carbon. The different activated carbons were applied at the concentration recommended by the manufacturer in order to evaluate their efficiency in reducing OTA levels. Trial and OTA analysis were performed as explained previously. The results showed that in white wine all activated carbons except one reduced 100% of OTA. The commercial formulation that contains gelatine, bentonite and activated carbon (C8) reduced only 73% of OTA concentration. These results may provide useful information for winemakers, namely for the selection of the most appropriate oenological product for OTA removal, reducing wine toxicity and simultaneously enhancing food safety and wine quality.

Engineering a commercial cold-adapted xylanase for improved low pH stability

Dissertação de mestrado em Genética Molecular