32 resultados para Tandem repeat


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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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Serious games are starting to attain a higher role as tools for learning in various contexts, but in particular in areas such as education and training. Due to its characteristics, such as rules, behavior simulation and feedback to the player's actions, serious games provide a favorable learning environment where errors can occur without real life penalty and students get instant feedback from challenges. These challenges are in accordance with the intended objectives and will self-adapt and repeat according to the student’s difficulty level. Through motivating and engaging environments, which serve as base for problem solving and simulation of different situations and contexts, serious games have a great potential to aid players developing professional skills. But, how do we certify the acquired knowledge and skills? With this work we intend to propose a methodology to establish a relationship between the game mechanics of serious games and an array of competences for certification, evaluating the applicability of various aspects in the design and development of games such as the user interfaces and the gameplay, obtaining learning outcomes within the game itself. Through the definition of game mechanics combined with the necessary pedagogical elements, the game will ensure the certification. This paper will present a matrix of generic skills, based on the European Framework of Qualifications, and the definition of the game mechanics necessary for certification on tour guide training context. The certification matrix has as reference axes: skills, knowledge and competencies, which describe what the students should learn, understand and be able to do after they complete the learning process. The guides-interpreters welcome and accompany tourists on trips and visits to places of tourist interest and cultural heritage such as museums, palaces and national monuments, where they provide various information. Tour guide certification requirements include skills and specific knowledge about foreign languages and in the areas of History, Ethnology, Politics, Religion, Geography and Art of the territory where it is inserted. These skills are communication, interpersonal relationships, motivation, organization and management. This certification process aims to validate the skills to plan and conduct guided tours on the territory, demonstrate knowledge appropriate to the context and finally match a good group leader. After defining which competences are to be certified, the next step is to delineate the expected learning outcomes, as well as identify the game mechanics associated with it. The game mechanics, as methods invoked by agents for interaction with the game world, in combination with game elements/objects allows multiple paths through which to explore the game environment and its educational process. Mechanics as achievements, appointments, progression, reward schedules or status, describe how game can be designed to affect players in unprecedented ways. In order for the game to be able to certify tour guides, the design of the training game will incorporate a set of theoretical and practical tasks to acquire skills and knowledge of various transversal themes. For this end, patterns of skills and abilities in acquiring different knowledge will be identified.

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Paracetamol is among the most worldwide consumed pharmaceuticals. Although its occurrence in the environment is well documented, data about the presence of its metabolites and transformation products is very scarce. The present work describes the development of an analytical method for the simultaneous determination of paracetamol, its principal metabolite (paracetamol-glucuronide) and its main transformation product (p-aminophenol) based on solid phase extraction (SPE) and high performance liquid chromatography coupled to diode array detection (HPLC-DAD). The method was applied to analysis of river waters, showing to be suitable to be used in routine analysis. Different SPE sorbents were compared and the use of two Oasis WAX cartridges in tandem proved to be the most adequate approach for sample clean up and pre-concentration. Under optimized conditions, limits of detection in the range 40–67 ng/L were obtained, as well as mean recoveries between 60 and 110% with relative standard deviations (RSD) below 6%. Finally, the developed SPE-HPLC/DAD method was successfully applied to the analysis of the selected compounds in samples from seven rivers located in the north of Portugal. Nevertheless all the compounds were detected, it was the first time that paracetamol-glucuronide was found in river water at concentrations up to 3.57 μg/L.

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QuEChERS original method was modified into a new version for pesticides determination in soils. The QuEChERS method is based on liquid–liquid portioning with ACN and was followed by cleanup step using dispersive SPE and disposable pipette tips. Gas chromatographic separation with MS detection was carried out for pesticides quantification. The method was validated using recovery experiments for 36 multiclass pesticides. Mean recoveries of pesticides at each of the four spiking levels between 10–300 µg/kg of soil ranged from 70–120% for 26 pesticides with RSD values less than 15%. The method achieved low limit of detection less than 7.6 µ g/kg. Matrix effects were observed for 13 pesticides. Matrix effects were compensated by using matrix-matched calibration. The method was applied successfully using d-SPE or DPX in the analysis of the pesticides in soils from organic farming and integrated pest management.

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An optimised version of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for simultaneous determination of 14 organochlorine pesticides in carrots was developed using gas chromatography coupled with electron-capture detector (GC-ECD) and confirmation by gas chromatography tandem mass spectrometry (GC-MS/MS). A citrate-buffered version of QuEChERS was applied for the extraction of the organochlorine pesticides, and for the extract clean-up, primary secondary amine, octadecyl-bonded silica (C18), magnesium sulphate (MgSO4) and graphitized carbon black were used as sorbents. The GC-ECD determination of the target compounds was achieved in less than 20 min. The limits of detection were below the EUmaximum residue limits (MRLs) for carrots, 10–50 μg kg−1, while the limit of quantification did exceed 10 μg kg−1 for hexachlorobenzene (HCB). The introduction of a sonication step was shown to improve the recoveries. The overall average recoveries in carrots, at the four tested levels (60, 80, 100 and 140 μg kg−1), ranged from 66 to 111% with relative standard deviations in the range of 2– 15 % (n03) for all analytes, with the exception of HCB. The method has been applied to the analysis of 21 carrot samples from different Portuguese regions, and β-HCH was the pesticide most frequently found, with concentrations oscillating between less than the limit of quantification to 14.6 μg kg−1. Only one sample had a pesticide residue (β-HCH) above the MRL, 14.6 μg kg−1. This methodology combines the advantages of both QuEChERS and GC-ECD, producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.

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Radio interference drastically affects the performance of sensor-net communications, leading to packet loss and reduced energy-efficiency. As an increasing number of wireless devices operates on the same ISM frequencies, there is a strong need for understanding and debugging the performance of existing sensornet protocols under interference. Doing so requires a low-cost flexible testbed infrastructure that allows the repeatable generation of a wide range of interference patterns. Unfortunately, to date, existing sensornet testbeds lack such capabilities, and do not permit to study easily the coexistence problems between devices sharing the same frequencies. This paper addresses the current lack of such an infrastructure by using off-the-shelf sensor motes to record and playback interference patterns as well as to generate customizable and repeat-able interference in real-time. We propose and develop JamLab: a low-cost infrastructure to augment existing sensornet testbeds with accurate interference generation while limiting the overhead to a simple upload of the appropriate software. We explain how we tackle the hardware limitations and get an accurate measurement and regeneration of interference, and we experimentally evaluate the accuracy of JamLab with respect to time, space, and intensity. We further use JamLab to characterize the impact of interference on sensornet MAC protocols.

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Remote Labs are an emergent educational resource in Engineering, which addresses the remote delivery of practical contents, i. e. remote experiments, through the web. This resource may either be used as a support for e-learning courses in Engineering or Science, in the cases where on-campus lab work is not possible, or as a complement to face-to-face lab classes, allowing the students to repeat a given experiment on a remote fashion, without time restrictions.

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The results presented in the article are part of a wider PhD project developed under the Doctoral program in Multimedia in Education from the University of Aveiro. The project, which sought to understand student ID in Higher education through the use of Digital Storytelling, was made possible through the Doctoral Grant awarded by Fundação para a Ciência e Tecnologia (FCT).

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This study analysed 22 strawberry and soil samples after their collection over the course of 2 years to compare the residue profiles from organic farming with integrated pest management practices in Portugal. For sample preparation, we used the citrate-buffered version of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. We applied three different methods for analysis: (1) 27 pesticides were targeted using LC-MS/MS; (2) 143 were targeted using low pressure GC-tandem mass spectrometry (LP-GC-MS/MS); and (3) more than 600 pesticides were screened in a targeted and untargeted approach using comprehensive, two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS). Comparison was made of the analyses using the different methods for the shared samples. The results were similar, thereby providing satisfactory confirmation of both similarly positive and negative findings. No pesticides were found in the organic-farmed samples. In samples from integrated pest management practices, nine pesticides were determined and confirmed to be present, ranging from 2 μg kg−1 for fluazifop-pbutyl to 50 μg kg−1 for fenpropathrin. Concentrations of residues in strawberries were less than European maximum residue limits.

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A situação económica instável vivida atualmente, aliada à crescente agressividade concorrencial obriga as organizações a evoluírem continuamente, melhorando a sua forma de trabalhar e de se apresentar ao mercado. Com a elaboração deste trabalho pretendeu-se analisar o processo de vendas, com maior enfoque no segmento de clientes Indústria, de modo a identificar possíveis desperdícios que ocorrem ao longo do processo, e criar um plano de ações corretivas e de melhoria, utilizando, para isso, ferramentas da qualidade. Neste relatório, descreve-se o processo atual na empresa, fazendo um estudo exaustivo ao mesmo. Com os dados recolhidos, desenvolveu-se um plano de ações para melhorar os vários processos com o objetivo de eliminar ou reduzir os desperdícios encontrados. Todas as ações corretivas que foram implementadas foram sujeitas a uma avaliação de desempenho, constatando-se uma melhoria do desempenho dos subprocessos tanto de forma quantitativa como qualitativa.

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Identity achievement is related to personality, as well as cognitive and interpersonal development. In tandem with the deep structural changes that have taken place in society, education must also shift towards a teaching approach focused on learning and the overall development of the student. The integration of technology may be the drive to foster the needed changes. We draw on the literature of multiple subject areas as basis for our work, namely: identity construction and self-representation, within a psychological and social standpoint; Higher Education (HE) in Portugal after Bologna, college student development and other intrinsic relationships, namely the role of emotions and interpersonal relationships in the learning process; the technological evolution of storytelling towards Digital Storytelling (DS) – the Californian model – and its connections to identity and education. Ultimately we propose DS as the aggregator capable of humanizing HE while developing essential skills and competences. Grounded on an interpretative/constructivist paradigm, we implemented a qualitative case study to explore DS in HE. In three attempts to collect student data, we gathered detailed observation notes from two Story Circles; twelve student written reflections; fourteen Digital Stories and detailed observation notes from one Story Show. We carried out three focus groups with teachers where we discussed their perceptions of each student prior to and after watching the Digital Stories, in addition to their opinion on DS in HE as a teaching and learning method and its influence on interpersonal relationships. We sought understandings of the integration of DS to analyze student selfperception and self-representation in HE contexts and intersected our findings with teachers’ perceptions of their students. We compared teachers’ and students’ perspectives, through the analysis of data collected throughout the DS process – Story Circle, Story Creation and Story Show – and triangulated that information with the students’ personal reflections and teacher perceptions. Finally we questioned if and how DS may influence teachers’ perceptions of students. We found participants to be the ultimate gatekeepers in our study. Very few students and teachers voluntarily came forth to take part in the study, confirming the challenge remains in getting participants to see the value and understand the academic rigor of DS. Despite this reluctance, DS proved to be an asset for teachers and students directly and indirectly involved in the study. DS challenges HE contexts, namely teacher established perception of students; student’s own expectations regarding learning in HE; the emotional realm, the private vs. public dichotomy and the shift in educational roles.

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Advanced glycation end-products are Maillard reaction products that are found in thermal processed food. This compounds are often referred as unhealthy for human diet, namely because of their capacity to form amino-acid dimers. There is a broad range of answers to get about how these products are formed, how they interact with the organism and how these reactions can be inhibited to prevent the referred effects. Some compounds from garlic are thought to be able to inhibit these reactions. This study using spectrophotometric, High Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS) and Fourier transformed infrared spectroscopy (FTIR) analysis, helps to understand better not only not only the effect of some compounds obtained from garlic, diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS), on these AGEs production reaction, but also helped to understand better the reaction itself.

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An analytical methodology for the simultaneous determination of seven pharmaceuticals and two metabolites belonging to the non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics therapeutic groups was developed based on off-line solid-phase extraction and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (SPE–UHPLC–MS/MS). Extraction conditions were optimized taking into account parameters like sorbent material, sample volume and sample pH. Method detection limits (MDLs) ranging from 0.02 to 8.18 ng/L were obtained. This methodology was successfully applied to the determination of the selected pharmaceuticals in seawater samples of Atlantic Ocean in the Northern Portuguese coast. All the pharmaceuticals have been detected in the seawater samples, with pharmaceuticals like ibuprofen, acetaminophen, ketoprofen and the metabolite hydroxyibuprofen being the most frequently detected at concentrations that can reach some hundreds of ng/L.

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In this study a citrate-buffered version of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method for determination of 14 organochlorine pesticides (OCPs) residues in tamarind peel, fruit and commercial pulp was optimized using gas chromatography (GC) coupled with electron-capture detector (ECD) and confirmation by GC tandem mass spectrometry (GC–MS/MS). Five procedures were tested based on the original QuEChERS method. The best one was achieved with increased time in ultrasonic bath. For the extract clean-up, primary secondary amine (PSA), octadecyl-bonded silica (C18) and magnesium sulphate (MgSO4) were used as sorbents for tamarind fruit and commercial pulp and for peel was also added graphitized carbon black (GCB). The samples mass was optimized according to the best recoveries (1.0 g for peel and fruit; 0.5 g for pulp). The method results showed the matrix-matched calibration curve linearity was r2 > 0.99 for all target analytes in all samples. The overall average recoveries (spiked at 20, 40 and 60 μg kg−1) have been considered satisfactory presenting values between 70 and 115% with RSD of 2–15 % (n = 3) for all analytes, with the exception of HCB (in peel sample). The ranges of limits of detection (LOD) and quantification (LOQ) for OCPs were for peel (LOD: 8.0–21 μg kg−1; LOQ: 27–98 μg kg−1); for fruit (LOD: 4–10 μg kg−1; LOQ: 15–49 μg kg−1) and for commercial pulp (LOD: 2–5 μg kg−1; LOQ: 7–27 μg kg−1). The method was successfully applied in tamarind samples being considered a rapid, sensitive and reliable procedure.

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Eruca sativa (rocket salad) has been intensely consumed all over the world, insomuch as, this work was undertaken to evaluate the antioxidant status and the environmental contamination (positive and negative nutritional contribution) of leaves and stems from this vegetable. Antioxidant capacity of rocket salad was assessed by mean of optical methods, such as the total phenolic content (TPC), reducing power assay and DPPH radical scavenging activity. The extent of the environmental contamination was reached through the quantification of thirteen organochlorine pesticides (OCP) by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing gas chromatography tandem mass-spectrometry (GC-MS/MS). The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology.The extent of the environmental contamination was reached through the quantification of thirteen OCP by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing GC-MS/MS. The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology. This demonstrated that leaves presented more antioxidant activity than stems, emphasizing that leaves contained six times more polyphenolic compounds than stems. In what concerns the OCP occurrence, the average recoveries obtained at the three levels tested (40, 60 and 80 µg kg−1) ranged from 55% to 149% with a relative standard deviation of 11%, (except hexachrorobenzene). Three vegetables samples were collected from supermarkets and analysed following this study. According to data, only one sample achieved 16.21 of β-hexachlorocyclohexane, confirmed by GC-MS/MS. About OCP quantification, the data indicated that only one sample achieved 16.21 µg kg−1 of β-hexachlorocyclohexane, confirmed by GC-MS/MS, being the QuEChERS a good choice for the of OCPs extraction. Furthermore, the leaves consumption guaranty higher levels of antioxidants than stems.