940 resultados para acquisition derivative
Resumo:
This study analyzes the interference of native language when students are learning a foreign language, in this case English. According to this study, interferences from the native language such as lexical-semantic and phonological are not infrequent. It is one of the main barriers that create difficulties when learning English. The outcome of this study is presented at the end of the Monografia: to provide English-language teachers and students the most significant linguistic interferences that occur during the learning process of English language. Furthermore, some teaching strategies are discussed to avoid the biases that appear due to the interferences of the native language. As a result of this study, I hope to contribute to the learning success among English-language students.
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We see that the price of an european call option in a stochastic volatilityframework can be decomposed in the sum of four terms, which identifythe main features of the market that affect to option prices: the expectedfuture volatility, the correlation between the volatility and the noisedriving the stock prices, the market price of volatility risk and thedifference of the expected future volatility at different times. We alsostudy some applications of this decomposition.
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Two-stage game models of information acquisition in stochastic oligopoliesrequire the unrealistic assumption that firms observe the precision ofinformation chosen by their competitors before determining quantities. Thispaper analyzes secret information acquisition as a one-stage game. Relativeto the two-stage game firms are shown to acquire less information. Policyimplications based on the two-stage game yield, therefore, too high taxes ortoo low subsidies for research activities. For the case of heterogeneousduopoly it is shown that comparative statics results partly depend on theobservability assumption.
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This study examines syntactic and morphological aspects of the production and comprehension of pronouns by 99 typically developing French-speaking children aged 3 years, 5 months to 6 years, 5 months. A fine structural analysis of subject, object, and reflexive clitics suggests that whereas the object clitic chain crosses the subject chain, the reflexive clitic chain is nested within it. We argue that this structural difference introduces differences in processing complexity, chain crossing being more complex than nesting. In support of this analysis, both production and comprehension experiments show that children have more difficulty with object than with reflexive clitics (with more omissions in production and more erroneous judgments in sentences involving Principle B in comprehension). Concerning the morphological aspect, French subject and object pronouns agree in gender with their referent. We report serious difficulties with pronoun gender both in production and comprehension in children around the age of 4 (with nearly 30% errors in production and chance level judgments in comprehension), which tend to disappear by age 6. The distribution of errors further suggests that the masculine gender is processed as the default value. These findings provide further insights into the relationship between comprehension and production in the acquisition process.
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The synthesis of a photoreactive derivative of the human leukocyte antigen-A1 (HLA-A1)-restricted MAGE-1 peptide 161-169 (EADPTGHSY) is described. Using conventional automated solid-phase peptide synthesis, a photoreactive derivative of this peptide was synthesized by replacing histidine-167 with photo-reactive N-beta-4-azidosalicyloyl-L-2,3-diaminopropionic acid. The C-terminal tyrosine was incorporated as phosphotyrosine. This peptide derivative was radioiodinated in the presence of chloramine T. This iodination took place selectively at the photoreactive group, because the phosphate ester prevented tyrosine iodination. Following dephosphorylation with alkaline phosphatase and chromatographic purification, the radiolabeled peptide derivative was incubated with cells expressing HLA-A1 or other HLA molecules. Photoactivation resulted in efficient photoaffinity labeling of HLA-A1. Other HLA molecules or other cellular components were not detectably labeled. This labeling was inhibited by HLA-A1 but not by HLA-A2-binding peptides. This synthesis is generally applicable and can also be adapted to the synthesis of well-defined radiolabeled nonphotoreactive peptide derivatives.
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This paper analyzes the choice between different innovationactivities of a firm. In particular, we study the technologyacquisition decision of the firm, i.e. its technology BUYdecision as part of the firm's innovation strategy. We take a closer look at the different types of external technologyacquisition where we distinguish two broad types of technologybuy decisions. On the one hand, the firm can acquire new technology which is embodied in an asset that is acquired suchas new personnel or (parts of) other firms or equipment. On the other hand, the firm can obtain new technology disembodiedthrough a licensing agreement or by outsourcing the technologydevelopment from an R&D contractor or consulting agency. Through a series of Probit regressions, we discuss variables that might affect external technology acquisition choices of the firm andpay special attention to the firm's abilities to scan the market for technology and to absorb the technology acquired. Furthermore, we analyze the effect of different appropriationregimes on the decision of the firm to source technology.
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Stimulated echoes are widely used for imaging functional tissue parameters such as diffusion coefficient, perfusion, and flow rates. They are potentially interesting for the assessment of various cardiac functions. However, severe limitations of the stimulated echo acquisition mode occur, which are related to the special dynamic properties of the beating heart and flowing blood. To the well-known signal decay due to longitudinal relaxation and through-plane motion between the preparation and the read-out period of the stimulated echoes, additional signal loss is often observed. As the prepared magnetization is fixed with respect to the tissue, this signal loss is caused by the tissue deformation during the cardiac cycle, which leads to a modification of the modulation frequency of the magnetization. These effects are theoretically derived and corroborated by phantom and in vivo experiments.
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Situados en el contexto catalán, el artículo estudia la influencia de la L1 (rumano) en algunos aspectos morfosintácticos de la adquisición de las L2s. Para ello se analizan las competencias lingüísticas en catalán y castellano de un grupo de escolares cuya L1 es el rumano y que cursan 2.º y 4.º de ESO. Los datos muestran que los alumnos cuya L1 es el rumano, a pesar de dominar una lengua románica cercana a las lenguas de aprendizaje (L2/L3), presentan dificultades comparables a otros colectivos con otras lenguasde origen. Por otra parte, nuestra investigación confirma que la L1 de este alumnado juega un importante papel en la adquisición de ambas lenguas, concluyendo que parte de los errores hallados son aquellos que se basan en estructuras de la lengua propia
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Objectives: Recent population genetic studies suggest that the Staphylococcal Chromosome Cassettes mec (SCCmec) was acquired at a global scale much more frequently than previously thought. We hypothesized that such acquisitions can also be observed at a local level. In the present study, we aimed at investigating the diversity of SCCmec in a local MRSA population, where the dissemination of four MRSA clones has been observed (JCM 2007, 45: 3729). Methods: All the MRSA isolates (one per patient) recovered in the Vaud canton of Switzerland from January 2005 to December 2008 were analyzed in this study. We used the Double Locus Sequence Typing (DLST) method, based on clfB and spa loci, and the e-BURST algorithm to group the types with one allele in common (i.e. clone). To increase the discriminatory power of the DLST method, a third polymorphic marker (clfA) was further analyzed on a sub-sample of isolates. The SCCmec type of each isolate was determined with the first two PCRs of the Kondo scheme. Results: DLST analysis indicated that 1884/2036 isolates (92.5%) belong to the four predominant clones. A majority of isolates in each clone harboured an identical SCCmec type: 61/64 (95%) isolates to DLST clone 1−1 SCCmec IV, 1282/1323 (97%) to clone 2−2 SCCmec II, 237/288 (82%) to clone 3−3 SCCmec IV, and 192/209 (92%) to clone 4−4 SCCmec I. Unexpectedly, different SCCmec types were present in a single predominant DLST clone: SCCmec V plus one unusual type in 3 isolates of clone 1−1; SCCmec I, IV, V, VI plus two unusual types in 41 isolates of clone 2−2; SCCmec I, II, VI plus three unusual types in 51 isolates of clone 3−3; and SCCmec II, IV, V plus one unusual type in 17 isolates of clone 4−4. Interestingly, adding a third locus generally did not change the classification of incongruent SCCmec types, suggesting that these SCCmec elements have been acquired locally during the dissemination of the clones. Conclusion: Although the SCCmec diversity within clones was relatively low at a local level, a significant proportion of isolates with different SCCmec have been identified in the four major clones. This suggests that the local acquisition of SCCmec elements is not a rare event and illustrates the great capacity of S. aureus to quickly adapt to its environment by acquiring new genetic elements.
Copper acquisition by the SenC protein regulates aerobic respiration in Pseudomonas aeruginosa PAO1.
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Aerobic respiration of Pseudomonas aeruginosa involves four terminal oxidases belonging to the heme-copper family (that is, three cytochrome c oxidases and one quinol oxidase) plus one copper-independent, cyanide-insensitive quinol oxidase (CIO). The PA0114 gene encoding an SCO1/SenC-type protein, which is known to be important for copper delivery to cytochrome c in yeast, Rhodobacter spp. and Agrobacterium tumefaciens, was found to be important for copper acquisition and aerobic respiration in P. aeruginosa. A PA0114 (senC) mutant grew poorly in low-copper media and had low cytochrome cbb(3)-type oxidase activity, but expressed CIO at increased levels, by comparison with the wild-type PAO1. Addition of copper reversed these phenotypes, suggesting that periplasmic copper capture by the SenC protein helps P. aeruginosa to adapt to copper deprivation.
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Developing a novel technique for the efficient, noninvasive clinical evaluation of bone microarchitecture remains both crucial and challenging. The trabecular bone score (TBS) is a new gray-level texture measurement that is applicable to dual-energy X-ray absorptiometry (DXA) images. Significant correlations between TBS and standard 3-dimensional (3D) parameters of bone microarchitecture have been obtained using a numerical simulation approach. The main objective of this study was to empirically evaluate such correlations in anteroposterior spine DXA images. Thirty dried human cadaver vertebrae were evaluated. Micro-computed tomography acquisitions of the bone pieces were obtained at an isotropic resolution of 93μm. Standard parameters of bone microarchitecture were evaluated in a defined region within the vertebral body, excluding cortical bone. The bone pieces were measured on a Prodigy DXA system (GE Medical-Lunar, Madison, WI), using a custom-made positioning device and experimental setup. Significant correlations were detected between TBS and 3D parameters of bone microarchitecture, mostly independent of any correlation between TBS and bone mineral density (BMD). The greatest correlation was between TBS and connectivity density, with TBS explaining roughly 67.2% of the variance. Based on multivariate linear regression modeling, we have established a model to allow for the interpretation of the relationship between TBS and 3D bone microarchitecture parameters. This model indicates that TBS adds greater value and power of differentiation between samples with similar BMDs but different bone microarchitectures. It has been shown that it is possible to estimate bone microarchitecture status derived from DXA imaging using TBS.