Browsing by Issue Date, starting with "2014-01-17"
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- Determinação do teor de ácidos gordos trans em amostras de alimentos da região centro de PortugalPublication . Oliveira, Fabiana Filipa Gomes da Silva; Varejão, Jorge Manuel Tavares BrancoRESUMO A ingestão de ácidos gordos trans tem originado uma preocupação crescente nos últimos anos. Vários estudos têm demonstrado fortes evidências entre a ingestão de ácidos gordos trans derivados de gorduras hidrogenadas e o aumento do LDL (lipoproteína de baixa densidade), assim como a diminuição do HDL (lipoproteína de alta densidade) e, por consequência, um aumento do risco de doença cardíaca coronária. Recorrendo à cromatografia gasosa de alta resolução, foram analisadas 50 amostras de produtos comercializados na zona centro do país. As amostras além de serem suscetíveis de terem na sua formulação gordura hidrogenada, são de igual modo, alimentos comuns na dieta diária dos portugueses. O teor médio de ácidos gordos trans presentes nas amostras analisadas foi de 2,00 ± 0,60 % do total dos ácidos gordos, 17 amostras (cerca de 34% do total das amostras) apresentaram valores superiores a 2% e, dessas, 4 amostras ultrapassam os 6%. A amostra com maior teor de ácidos gordos trans atingiu um valor superior a 10% (10,50 ± 3,25%) do total dos ácidos gordos. Os teores mais elevados de ácidos gordos trans foram encontrados, maioritariamente, em produtos constituídos por massa folhada e adquiridos em pastelarias. Palavras-chave: Cromatografia gasosa; Hidrogenação; ácidos gordos trans; alimentos portugueses; doença cardíaca coronária; ii ABSTRACT The intake of trans fatty acids has led to a growing health concern in the last few years. Several studies have shown strong evidence between the intake of trans fatty acids originated from hydrogenated fats and increasing LDL (low density lipoprotein) as well as the decrease in HDL (high-density lipoprotein) and, by consequence an increase in the risk of coronary heart disease. Were analyzed 50 samples of products marketed in the center of Portugal using the high-resolution gas chromatography. The samples besides being capable of having hydrogenated fat in the formulation are likewise common foods in the daily diet of the Portuguese people. The mean of trans fatty acids content present in the samples was 2.00 ± 0.60% of the total fatty acids, 17 samples (about 34% of total samples) showed more than 2% and, of these, 4 samples were above 6%. The sample with the highest content of trans fatty acids has reached a value above 10% (10.50 ± 3.25%) of total fatty acids. The highest levels of trans fatty acids were predominantly found in products made of puff pastry and pastry shops acquired. Key-words: Gas chromatography; hydrogenation; trans fatty acids; Portuguese food; coronary heart disease.
- Measurement of Higgs boson production and properties in the WW decay channel with leptonic final statesPublication . CMS collaboration (2207 authors); Hollar, Jonathan; Nayak, Aruna; Calpas, Betty; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Nguyen, Federico; Rodrigues Antunes, Joao; Seixas, Joao; Varela, Joao; Vischia, Pietro; Lloret Iglesias, Lara; David Tinoco Mendes, Andre; Musella, Pasquale; Silva, Pedro; Pela, Joao; Leonardo, NunoA search for the standard model Higgs boson decaying to a W-boson pair at the LHC is reported. The event sample corresponds to an integrated luminosity of 4.9 and 19.4 inverse femtobarns collected with the CMS detector in pp collisions at sqrt(s) = 7 and 8 TeV, respectively. The Higgs boson candidates are selected in events with two or three charged leptons. An excess of events above background is observed, consistent with the expectation from the standard model Higgs boson with a mass of around 125 GeV. The probability to observe an excess equal or larger than the one seen, under the background-only hypothesis, corresponds to a significance of 4.3 standard deviations for m[H] = 125.6 GeV. The observed signal cross section times the branching fraction to WW for m[H] = 125.6 GeV is 0.72+0.20-0.18 times the standard model expectation. The spin-parity J(P)=0(+) hypothesis is favored against a narrow resonance with J(P)=2(+) or J(P)=0(-) that decays to a W-boson pair. This result provides strong evidence for a Higgs-like boson decaying to a W-boson pair.