899 resultados para Rapid Prottyping
Resumo:
O estudo científico dos correlatos cognitivos da aquisição e desenvolvimento da competência de leitura é um assunto de grande relevância quer teórica quer prática, no sentido em que pode ajudar a compreender os processos cognitivos básicos envolvidos na leitura e, em última instância, a delinear os seus preditores e a predizer dificuldades na sua aquisição. A par da consciência fonológica – capacidade para perceber e manipular as unidades de som –, um dos construtos que frequentemente tem sido associado ao desenvolvimento da competência de leitura é a velocidade de nomeação de estímulos visuais (também conhecida como nomeação rápida automatizada ou velocidade de acesso ao léxico). Tradicionalmente, esta capacidade tem sido avaliada recorrendo ao paradigma clássico das provas de nomeação rápida automatizada (RAN) desenvolvidas por Denckla e Rudel (1976), nas quais é pedido ao sujeito que nomeie o mais rapidamente possível um conjunto de estímulos familiares apresentados serialmente. Nas últimas décadas, inúmeros estudos vieram demonstrar que a nomeação rápida é um importante preditor da competência de leitura, sobretudo da fluência da leitura, e um défice central em perturbações de leitura como a dislexia. O desempenho numa tarefa de nomeação rápida apela à sincronização e integração de vários processos, incluindo: (a) atenção ao estímulo, (b) integração da informação visual com representações visuais ou ortográficas arquivadas em memória, (c) recuperação de uma etiqueta verbal, e a (d) ativação da representação articulatória (Wolf & Bowers, 1999). Uma vez que a leitura e a nomeação rápida envolvem processos cognitivos semelhantes, não parece surpreendente que ambas as competências estejam associadas. No entanto, os estudos têm variado consideravelmente no que respeita à magnitude da associação entre a nomeação rápida e a leitura, encontrando-se resultados nulos ou negligenciáveis do valor preditivo da nomeação rápida na explicação da variância do desempenho de leitura. Vários fatores podem contribuir para as discrepâncias observadas na literatura, entre os quais as medidas utilizadas para avaliar o desempenho de nomeação rápida (por exemplo, medidas que utilizam estímulos ortográficos ou não-ortográficos) e de leitura (por exemplo, medidas de fluência ou de acuidade). A importância da natureza das medidas quer de nomeação rápida quer de leitura tem sido reconhecida por vários autores (para uma revisão, ver Norton & Wolf, 2011). Paralelamente, as amostras estudadas, que têm variado quanto à idade/escolaridade dos participantes e à sua competência de leitura (leitores normais ou fracos leitores ou leitores disléxicos), poderão estar a contribuir para a heterogeneidade dos resultados publicados. A literatura recente tem salientado a relevância destes fatores na aquisição e desenvolvimento da leitura, embora a direccionalidade do seu efeito seja ainda pouco clara. Por exemplo, a transição de um procedimento de leitura baseado em estratégias de descodificação fonológica para uma leitura automática, à medida que o sujeito se torna um leitor fluente, parece ser acompanhada por uma mudança no peso relativo das capacidades cognitivas subjacentes à leitura (ex., Reis, Faísca, Castro, & Petersson, in press). Outro fator importante que tem dificultado a interpretação dos dados publicados sobre os construtos envolvidos na leitura, e em particular sobre a nomeação rápida, relaciona-se com a consistência ortográfica do sistema de escrita nos quais os estudos são conduzidos. Estudos trans-linguísticos sugerem que a consistência ortográfica influencia a facilidade com que se aprende a ler nas escritas alfabéticas, bem como o tipo de processamento de leitura predominantemente adotado pelos leitores (Seymour, Aro, & Erskine, 2003). No seio deste enquadramento, nesta tese procurámos clarificar as divergências encontradas na literatura relativamente à relação entre a nomeação rápida e o desempenho de leitura. Através de um estudo de meta-análise 1 é nosso objetivo realizar uma síntese objetiva do estado da arte sobre a relação entre a nomeação rápida e a leitura, e avaliar a influência de potenciais fatores moderadores da magnitude desta relação, nomeadamente: (a) a natureza da tarefa de nomeação (tipo de estímulo nomeado, número total de itens, e número de itens diferentes); (b) a natureza da tarefa de leitura (subcomponente de leitura, e medida de resposta usada para avaliar o desempenho); (c) características da amostra (escolaridade e nível de leitura); e (d) ortografia (sistema de escrita, e consistência ortográfica). Para tal, foi realizada uma procura de artigos científicos nas bases de dados PubMed, PsycINFO, e Web of Knowledge, tendo sido incluídas na meta-análise um total de 154 experiências independentes, compreendendo 21,706 participantes. Os resultados indicam uma relação moderada-a-forte entre a nomeação rápida e o desempenho de leitura (r =.44, I2 = 71.19). Nas análises seguintes procurou-se avaliar o contributo de potenciais variáveis moderadoras que possam explicar a heterogeneidade observada entre os tamanhos dos efeitos. Verificou-se que a nomeação rápida se associa significativamente e em magnitude semelhante com todas as medidas de leitura, i.e., quer estas apelem preferencialmente a um processamento de descodificação fonológica ou de reconhecimento de padrões ortográficos da palavra. Os resultados sugerem ainda que a magnitude das correlações é inflacionada nos estudos em que o desempenho de leitura é baseado na velocidade/fluência de leitura, em particular nos níveis de escolaridade mais avançados, e que utilizam tarefas de nomeação com estímulos alfanuméricos ao invés de estímulos não-alfanuméricos. Adicionalmente, verificou-se que a força da associação entre a nomeação rápida e a acuidade de leitura varia de forma não linear durante a evolução da leitura, sendo que a correlação é maior nos leitores escolarizados mais novos e decresce à medida que a escolaridade aumenta. O papel atribuível à proficiência dos leitores, i.e., fracos leitores/leitores disléxicos ou leitores normais, foi menos claro; no entanto, houve uma tendência para a relação ser mais forte nas amostras de fracos leitores/leitores disléxicos. Os resultados das comparações trans-linguísticas, por sua vez, sugerem que a nomeação rápida tem um papel importante para o desempenho da leitura independentemente das características da ortografia, ainda que as correlações tenham sido maiores nas ortografias opacas, e em particular nas línguas não-alfabéticas. Em suma, a presente meta-análise fornece resultados convincentes de que o desempenho em tarefas de nomeação rápida refletirá processos cognitivos subjacentes que são também relevantes para a aquisição/desenvolvimento da leitura. Consequentemente, pode dizer-se que estas medidas serão um preditor útil da competência de leitura. Os resultados são também discutidos no contexto das teorias atuais que procuram explicar através de que processos cognitivos se associam a nomeação rápida e a leitura, com ênfase nas hipóteses fonológica versus ortográfica. 1 Uma meta-análise permite a integração quantitativa de resultados de diversos estudos, recorrendo para isso à noção de magnitude do efeito.
Resumo:
The Acoustic Oceanographic Buoy (AOB) Telemetry System has been designed to meet acoustic rapid environmental assessment requirements. It uses a standard institute of Electrical and Electronics Engineers 802.11 wireless local area network (WLAN) to integrate the air radio network (RaN) and a hydrophone array and acoustic source to integrate the underwater acoustic network (AcN). It offers advantages including local data storage, dedicated signal processing, and global positioning system (GPS) timing and localization. The AOB can also be integrated with other similar systems, due to its WLAN transceivers, to form a flexible network and perform on-line high speed data transmissions. The AOB is a reusable system that requires less maintenance and can also work as a salt-water plug-and-play system at sea as it is designed to operate in free drifting mode. The AOB is also suitable for performing distributed digital signal processing tasks due to its digital signal processor facility.
Resumo:
Freshness and safety of muscle foods are generally considered as the most important parameters for the food industry. To address the rapid detection of meat spoilage microorganisms during aerobic or modified atmosphere storage, an electronic nose with the aid of fuzzy wavelet network has been considered in this research. The proposed model incorporates a clustering pre-processing stage for the definition of fuzzy rules. The dual purpose of the proposed modelling approach is not only to classify beef samples in the respective quality class (i.e. fresh, semi-fresh and spoiled), but also to predict their associated microbiological population directly from volatile compounds fingerprints. Comparison results against neural networks and neurofuzzy systems indicated that the proposed modelling scheme could be considered as a valuable detection methodology in food microbiology
Resumo:
The use of perceptual inputs is an emerging area within HCI that suggests a developing Perceptual User Interface (PUI) that may prove advantageous for those involved in mobile serious games and immersive social network environments. Since there are a large variety of input devices, software platforms, possible interactions, and myriad ways to combine all of the above elements in pursuit of a PUI, we propose in this paper a basic experimental framework that will be able to standardize study of the wide range of interactive applications for testing efficacy in learning or information retrieval and also suggest improvements to emerging PUIs by enabling quick iteration. This rapid iteration will start to define a targeted range of interactions that will be intuitive and comfortable as perceptual inputs, and enhance learning and information retention in comparison to traditional GUI systems. The work focuses on the planning of the technical development of two scenarios, and the first steps in developing a framework to evaluate these and other PUIs for efficacy and pedagogy.
Resumo:
Sulfadiazine is an antibiotic of the sulfonamide group and is used as a veterinary drug in fish farming. Monitoring it in the tanks is fundamental to control the applied doses and avoid environmental dissemination. Pursuing this goal, we included a novel potentiometric design in a flow-injection assembly. The electrode body was a stainless steel needle veterinary syringe of 0.8-mm inner diameter. A selective membrane of PVC acted as a sensory surface. Its composition, the length of the electrode, and other flow variables were optimized. The best performance was obtained for sensors of 1.5-cm length and a membrane composition of 33% PVC, 66% onitrophenyloctyl ether, 1% ion exchanger, and a small amount of a cationic additive. It exhibited Nernstian slopes of 61.0 mV decade-1 down to 1.0×10-5 mol L-1, with a limit of detection of 3.1×10-6 mol L-1 in flowing media. All necessary pH/ionic strength adjustments were performed online by merging the sample plug with a buffer carrier of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, pH 4.9. The sensor exhibited the advantages of a fast response time (less than 15 s), long operational lifetime (60 days), and good selectivity for chloride, nitrite, acetate, tartrate, citrate, and ascorbate. The flow setup was successfully applied to the analysis of aquaculture waters. The analytical results were validated against those obtained with liquid chromatography–tandem mass spectrometry procedures. The sampling rate was about 84 samples per hour and recoveries ranged from 95.9 to 106.9%.
Resumo:
OBJECTIVES: To assess attitudes to HIV risk and acceptability of rapid HIV testing among clients of street-based female sex workers (FSW) in Lausanne, Switzerland, where HIV prevalence in the general population is 0.4%. METHODS: The authors conducted a cross-sectional study in the red light district of Lausanne for five nights in September of 2008, 2009 and 2010. Clients of FSW were invited to complete a questionnaire in the street assessing demographic characteristics, attitudes to HIV risk and HIV testing history. All clients interviewed were then offered anonymous finger stick rapid HIV testing in a van parked on-site. RESULTS: The authors interviewed 112, 127 and 79 clients in 2008, 2009 and 2010, respectively. All were men, average age 32-37 years old; 40-60% were in a stable relationship. History of unprotected sex was higher with non-commercial partners (33-50%) than with FSW (6-11%); 29-46% of clients had never undergone an HIV test. Anonymous rapid HIV testing was accepted by 45-50% of clients. Out of 109 HIV tests conducted during the three study periods, none was reactive. CONCLUSIONS: On-site HIV counselling and testing is acceptable among clients of FSW in this urban setting. These individuals represent an unquantified population, a proportion of which has an incomplete understanding of HIV risk in the face of high-risk behaviour, with implications for potential onward transmission to non-commercial sexual partners.
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Adaptive immunity is initiated in T-cell zones of secondary lymphoid organs. These zones are organized in a rigid 3D network of fibroblastic reticular cells (FRCs) that are a rich cytokine source. In response to lymph-borne antigens, draining lymph nodes (LNs) expand several folds in size, but the fate and role of the FRC network during immune response is not fully understood. Here we show that T-cell responses are accompanied by the rapid activation and growth of FRCs, leading to an expanded but similarly organized network of T-zone FRCs that maintains its vital function for lymphocyte trafficking and survival. In addition, new FRC-rich environments were observed in the expanded medullary cords. FRCs are activated within hours after the onset of inflammation in the periphery. Surprisingly, FRC expansion depends mainly on trapping of naïve lymphocytes that is induced by both migratory and resident dendritic cells. Inflammatory signals are not required as homeostatic T-cell proliferation was sufficient to trigger FRC expansion. Activated lymphocytes are also dispensable for this process, but can enhance the later growth phase. Thus, this study documents the surprising plasticity as well as the complex regulation of FRC networks allowing the rapid LN hyperplasia that is critical for mounting efficient adaptive immunity.
Resumo:
BACKGROUND: Cancer/testis (CT) genes are normally expressed only in germ cells, but can be activated in the cancer state. This unusual property, together with the finding that many CT proteins elicit an antigenic response in cancer patients, has established a role for this class of genes as targets in immunotherapy regimes. Many families of CT genes have been identified in the human genome, but their biological function for the most part remains unclear. While it has been shown that some CT genes are under diversifying selection, this question has not been addressed before for the class as a whole. RESULTS: To shed more light on this interesting group of genes, we exploited the generation of a draft chimpanzee (Pan troglodytes) genomic sequence to examine CT genes in an organism that is closely related to human, and generated a high-quality, manually curated set of human:chimpanzee CT gene alignments. We find that the chimpanzee genome contains homologues to most of the human CT families, and that the genes are located on the same chromosome and at a similar copy number to those in human. Comparison of putative human:chimpanzee orthologues indicates that CT genes located on chromosome X are diverging faster and are undergoing stronger diversifying selection than those on the autosomes or than a set of control genes on either chromosome X or autosomes. CONCLUSION: Given their high level of diversifying selection, we suggest that CT genes are primarily responsible for the observed rapid evolution of protein-coding genes on the X chromosome.
Resumo:
Furosemide (FD: Lasix) is a loop diuretic which strongly increases both urine flow and electrolyte urinary excretion. Healthy volunteers were administered 40 mg orally (dissolved in water) and concentrations of FD were determined in serum and urine for up to 6 h for eight subjects, who absorbed water at a rate of 400 ml/h. Quantification was performed by HPLC with fluorescence detection (excitation at 233 nm, emission at 389 nm) with a limit of detection of 5 ng/ml for a 300-microliters sample. The elution of FD was completed within 4 min using a gradient of acetonitrile concentration rising from 30 to 50% in 0.08 M phosphoric acid. The delay to the peak serum concentration ranged from 60 to 120 min. FD was still easily measurable in the sera from all subjects 6 h after administration. In urine, the excretion rates reached their maximum between 1 and 3 h. The total amount of FD excreted in the urine averaged 11.2 mg (range 7.6-14.0 mg), with a mean urine volume of 3024 ml (range 2620-3596 ml). Moreover, the urine density was lower than 1.010 (recommended as an upper limit in doping analysis to screen diuretics) only for 2 h. An additional volunteer was administered 40 mg of FD and his urine was collected over a longer period. FD was still detectable 48 h after intake. Gas chromatography-mass spectrometry with different types of ionization was used to confirm the occurrence of FD after permethylation of the extract. Negative-ion chemical ionization, with ammonia as reactant gas, was found to be the most sensitive method of detection.
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We describe a calorimetric assay for detection of voriconazole-resistant Aspergillus fumigatus within 8 h. Among 27 genetically distinct strains, all 21 resistant and all 6 susceptible strains were correctly identified by measurement of fungal heat production in the presence of voriconazole. This proof-of-concept study demonstrates the potential of microcalorimetry for rapid detection of azole resistance in A. fumigatus.
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The last several years have seen an increasing number of studies that describe effects of oxytocin and vasopressin on the behavior of animals or humans. Studies in humans have reported behavioral changes and, through fMRI, effects on brain function. These studies are paralleled by a large number of reports, mostly in rodents, that have also demonstrated neuromodulatory effects by oxytocin and vasopressin at the circuit level in specific brain regions. It is the scope of this review to give a summary of the most recent neuromodulatory findings in rodents with the aim of providing a potential neurophysiological basis for their behavioral effects. At the same time, these findings may point to promising areas for further translational research towards human applications.
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Carbapenemases should be accurately and rapidly detected, given their possible epidemiological spread and their impact on treatment options. Here, we developed a simple, easy and rapid matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)-based assay to detect carbapenemases and compared this innovative test with four other diagnostic approaches on 47 clinical isolates. Tandem mass spectrometry (MS-MS) was also used to determine accurately the amount of antibiotic present in the supernatant after 1 h of incubation and both MALDI-TOF and MS-MS approaches exhibited a 100% sensitivity and a 100% specificity. By comparison, molecular genetic techniques (Check-MDR Carba PCR and Check-MDR CT103 microarray) showed a 90.5% sensitivity and a 100% specificity, as two strains of Aeromonas were not detected because their chromosomal carbapenemase is not targeted by probes used in both kits. Altogether, this innovative MALDI-TOF-based approach that uses a stable 10-μg disk of ertapenem was highly efficient in detecting carbapenemase, with a sensitivity higher than that of PCR and microarray.
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The nose is the anatomical site usually recommended for methicillin-resistant Staphylococcus aureus (MRSA) screening. Other sites are also recommended, but are more controversial. We showed that the sensitivities of MRSA detection from nasal swabs alone were 48% and 62% by culture or by rapid PCR test, respectively. These percentages increased to 79% and 92% with the addition of groin swabs, and to 96% and 99% with the addition of groin and throat swabs. In conclusion, neither by culture nor by rapid PCR test is nose sampling alone sufficient for MRSA detection. Additional anatomical sites should include at least the groin and throat.