6 resultados para Ipm

em Instituto Politécnico do Porto, Portugal


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O presente artigo pretende mostrar que, no cenário pré- Bolonha, em que se vivia numa época de aparente prosperidade económica, que se veio a revelar uma bolha especulativa semelhante à que teve lugar nos anos 20 do século passado, o ensino poderia considerar-se, detentor de alguma qualidade, apesar de, por vezes, continuar a seguir os cânones tradicionais expositivos do magisterdixit(Ardions 2011). A conjuntura económica obrigou a que fossem estancados projectos, pelo estrangulamento económico, afectando também as instituições de Ensino Superior. Uma tal situação conduziu ao retorno de muitos docentes de qualidade pedagógico-científica inquestionável, aos seus postos nos estabelecimentos do Ensino Secundário, perdendo, deste modo o vínculo de colaboradores. No cenário pós Bolonha esta situação ainda mais se agudizou, uma vez que o que se preconizou, em teoria, esbateu as realidades e tipicidades de cada país. Na prática, a diminuição do número de anos de ensino não conduziu a uma melhoria do ensino, (Ardions, 2011), mas esbarrou com vários problemas, cimentando diversas assimetrias e idiossincrasias que se irão detalhar, sempre a par com os cortes a nível económico. Esta conjuntura terá repercussão na gestão das instituições, fruto da perspectiva economicista que impera nos dias de hoje e que se reflecte em muitas decisões dos seus órgãos. Esta situação, bem como outras que se irão elencar, levam a uma desmotivação, a um desencanto da massa crítica que se encontra nos estabelecimentos de nível ensino, que opta por ficar passiva, sob pena de ser vista como oponente de um laxismo institucional que teima em persistir. Daí que se questionea razão de apenas se aferir, até agora,a Qualidade da Avaliação, da Certificação e da Acreditação e não a da Qualificação docente, nos diversos órgãos que têm nas suas mãos os destinos da Instituições.

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Consumer awareness, pesticide and fertilizer contaminations and environmental concerns have resulted in significant demand for organically grown farm produce. Consumption of berries has become popular among health-conscious consumers due to the high levels of valuable antioxidants, such as anthocyanins and other phenolic compounds. The present study evaluated the influence that organic farming (OF) and integrated pest management (IPM) practise exert on the total phenolic content in 22 strawberry samples from four varieties. Postharvest performance of OF and IPM strawberries grown in the same area in the centre of Portugal and harvested at the same maturity stage were compared. Chemical profiles (phenolic compounds) were determined with the aid of HPLC-DAD/MS. Total phenolic content was higher for OF strawberry extracts. This study showed that the main differences in bioactive phytochemicals between organically and IPM grown strawberries concerned their anthocyanin levels. Organically grown strawberries were significantly higher in antioxidant activity than were the IPM strawberries, as measured by DPPH and FRAP assays.

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Pesticides are among the most widely used chemicals in the world. Because of the widespread use of agricultural chemicals in food production, people are exposed to low levels of pesticide residues through their diets. Scientists do not yet have a total understanding of the health effects of these pesticide residues. This work aims to determine differences in terms of pesticide residue content in Portuguese strawberries grown using different agriculture practices. The Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation method was conducted and shown to have good performance for multiclass pesticides extraction in strawberries. The screening of 25 pesticides residue was performed by gas chromatography–tandem mass spectrometry. In quantitative validation, acceptable performances were achieved with recoveries of 70–120 and <12 % residual standard deviation for 25 pesticides. Good linearity was obtained for all the target compounds, with highly satisfactory repeatability. The limits of detection were in the range of 0.1–28 μg/kg. The method was applied to analyze strawberry samples from organic and integrated pest management (IPM) practices harvested in 2009–2010. The results showed the presence of fludioxonil, bifenthrin, mepanipyrim, tolylfluanid, cyprodinil, tetraconazole, and malathion when using IPM below the maximum residue levels.

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A rapid, specific, and sensitive method based on theQuick Easy Cheap Effective Rugged and Safe (QuEChERS) method and a cleanup using dispersive solid-phase extraction with MgSO4, PSA, and C18 sorbents has been developed for the routine analysis of 14 pesticides in strawberries. The analyses were performed by three different analytical methodologies: gas chromatography (GC) with electron capture detection (ECD), mass spectrometry (MS), and tandem mass spectrometry (MS/MS). The recoveries for all the pesticides studied were from 46 to 128%, with relative standard deviation of <15% in the concentration range of 0.005-0.250 mg/kg. The limit of detection (LOD) for all compoundsmetmaximumresidue limits (MRL) accepted in Portugal for organochlorine pesticides (OCP). A survey study of strawberries produced in Portugal in the years 2009-2010 obtained from organic farming (OF) and integrated pest management (IPM) was developed. Lindane and β-endosulfan were detected above the MRL in OF and IPM. Other OCP (aldrin, o,p0-DDT and their metabolites, and methoxychlor) were found below the MRL. The OCP residues detected decreased from 2009 to 2010. The QuEChERS method was successfully applied to the analysis of strawberry samples.

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In this study, we sought to assess the applicability of GC–MS/MS for the identification and quantification of 36 pesticides in strawberry from integrated pest management (IPM) and organic farming (OF). Citrate versions of QuEChERS (quick, easy, cheap, effective, rugged and safe) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for cleanup were compared for pesticide extraction. For cleanup, a combination of MgSO4, primary secondary amine and C18 was used for both the versions. Significant differences were observed in recovery results between the two sample preparation versions (DPX and d-SPE). Overall, 86% of the pesticides achieved recoveries (three spiking levels 10, 50 and 200 µg/kg) in the range of 70–120%, with <13% RSD. The matrix effects were also evaluated in both the versions and in strawberries from different crop types. Although not evidencing significant differences between the two methodologies were observed, however, the DPX cleanup proved to be a faster technique and easy to execute. The results indicate that QuEChERS with d-SPE and DPX and GC–MS/MS analysis achieved reliable quantification and identification of 36 pesticide residues in strawberries from OF and IPM.