994 resultados para 148-896A


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Using the polymerase chain reaction, the coding sequence for peanut agglutinin (PNA) was cloned and expressed in Escherichia coli. Amplified PNA is identical to previously reported cDNA, suggesting the absence of any introns in PNA gene. Recombinant (re-) PNA forms inclusion bodies in E. coli. Production of PNA was confirmed by probing Western blots with polyclonal anti-PNA immunoglobulin G. Inclusion bodies were solubilized with 6 M guanidine-HCl and renatured by rapid dilution in the presence of metal ions. The renatured lectin was then purified by affinity chromatography. The re-lectin shows carbohydrate-binding properties similar to the natural PNA. This expression system provides a model for future mutagenesis studies of the carbohydrate-binding site and thus facilitates ongoing efforts to explore the molecular basis for the specificity of lectin-carbohydrate interaction.

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Rare earth perchlorate-antipyrine (ap) complexes of the formula Ln (ClO4)3.6 ap have been prepared and characterised. Infrared and electronic spectra showed the co-ordination through carbonyl oxygen. Conductivity and molecular weight data indicated a co-ordination number of six for these complexes.

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The impact of Greek-Egyptian bilingualism on language use and linguistic competence is the key issue in this dissertation. The language use in a corpus of 148 Greek notarial contracts is analyzed on phonological, morphological and syntactic levels. The texts were written by bilingual notaries (agoranomoi) in Upper Egypt in the later Hellenistic period. They present, for the most part, very good administrative Greek. On the other hand, their language contains variation and idiosyncrasies that were earlier condemned as ungrammatical and bad Greek, and were not subjected to closer analysis. In order to reach plausible explanations for those phenomena, a thorough research into the sociohistorical and linguistic context was needed before the linguistic analysis. The general linguistic landscape, the population pattern and the status and frequency of Greek literacy in Ptolemaic Egypt in general, and in Upper Egypt in particular, are presented. Through a detailed examination of the notaries themselves (their names, families and handwriting), it became evident that there were one to three persons at the notarial office writing under the signature of one notary. Often the documents under one notary's name were written in the same hand. We get, therefore, exceptionally close to studying idiolects in written material from antiquity. The qualitative linguistic analysis revealed that the notaries made relatively few orthographic mistakes that reflect the ongoing phonological changes and they mastered the morphological forms. The problems arose at the syntactic level, for example, with the pattern of agreement between the noun groups or a noun with its modifiers. The significant structural differences between Greek and Egyptian can be behind the innovative strategies used by some of the notaries. Moreover, certain syntactic structures were clearly transferred from the notaries first language, Egyptian. This is obvious in the relative clause structure. Transfer can be found in other structures, as well, although, we must not forget the influence of parallel Greek structures. Sometimes these can act simultaneously. The interesting linguistic strategies and transfer features come mostly from the hand of one notary, Hermias. Some other notaries show similar patterns, for example, Hermias' cousin, Ammonios. Hermias' texts reveal that he probably spoke Greek more than his predecessors. It is possible to conclude, then, that the notaries of the later generations were more fluently bilingual; their two languages were partly integrated in their minds as an interlanguage combining elements from both languages. The earlier notaries had the two languages functionally separated and they followed the standardized contract formulae more rigidly.

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The paper deals with a linearization technique in non-linear oscillations for systems which are governed by second-order non-linear ordinary differential equations. The method is based on approximation of the non-linear function by a linear function such that the error is least in the weighted mean square sense. The method has been applied to cubic, sine, hyperbolic sine, and odd polynomial types of non-linearities and the results obtained are more accurate than those given by existing linearization methods.

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Spectrophotometric and potentiometric investigations have been carried out on copper-diethanolamine system. Job plots at 900, 900 and 580 mμ have indicated the formation of CuD++, CuD2++ and CuD3++. The n- pA curves obtained indicate the formation of CuD++, CuD2++, CuD3++, CuDOH+, CuD2OH+ and CuD3OH+. The n- pA curves have been analyzed to obtain the stability constants of these complexes. Absorption curves of pure complexes have been computed by a graphical method. Gaussian analysis of the absorption curves of pure and hydroxy complexes show the presence of a second band, indicating that the structure is that of a distorted octahedron.

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The recession that hit the Finnish economy at the beginning of the 1990s has been regarded as unusually severe. Organisations’ failure to survive the recession has been researched in their various aspects. However, the reasons for why and how organisations that survived did so have been explored to a somewhat lesser extent. This study concerns organisations that survived rather than those that failed to do so, as studying successful experiences is acknowledged as an important source for learning how to counteract future failure. The thesis examines four knowledge intensive organisations, with the focus on managerial and social aspects of the crisis handling processes. The study deals with managers’ and co-workers’ stories about organisational attempts to survive, rather than seeking to identify causal relationships. Drawing upon a narrative approach and a social constructionist perspective, the crisis handling processes are treated as reconstructions and rationalisations of what happened. A primary assumption of this thesis is that we make sense of experiences in retrospect, and the aim is to describe the handling of crisis situations and the hardships related to economic difficulties, by focusing on the interviewees’ explanations of how those difficulties were dealt with. The stories are about taking control despite the threats induced by an extremely severe economic recession, remaining active, how the managers and their co-workers dealt with the uncertainty experienced, and how the organisations subsequently survived. The analysis also interrogates such issues as trust, authenticity, legitimacy, identity and nostalgia in crisis contexts.

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Pricing American put options on dividend-paying stocks has largely been ignored in the option pricing literature because the problem is mathematically complex and valuation usually resorts to computationally expensive and impractical pricing applications. This paper computed a simulation study, using two different approximation methods for the valuation of American put options on a stock with known discrete dividend payments. This to find out if there were pricing errors and to find out which could be the most usable method for practical users. The option pricing models used in the study was the dividend approximation by Blomeyer (1986) and the one by Barone-Adesi and Whaley (1988). The study showed that the approximation method by Blomeyer worked satisfactory for most situations, but some errors occur for longer times to the dividend payment, for smaller dividends and for in-the-money options. The approximation method by Barone-Adesi and Whaley worked well for in-the-money options and at-the-money options, but had serious pricing errors for out-of-the-money options. The conclusion of the study is that a combination of the both methods might be preferable to any single model.

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In this study, we investigated measures of nonlinear dynamics and chaos theory in regards to heart rate variability in 27 normal control subjects in supine and standing postures, and 14 subjects in spontaneous and controlled breathing conditions. We examined minimum embedding dimension (MED), largest Lyapunov exponent (LLE) and measures of nonlinearity (NL) of heart rate time series. MED quantifies the system's complexity, LLE predictability and NL, a measure of deviation from linear processes. There was a significant decrease in complexity (P<0.00001), a decrease in predictability (P<0.00001) and an increase in nonlinearity (P=0.00001) during the change from supine to standing posture. Decrease in MED, and increases in NL score and LLE in standing posture appear to be partly due to an increase in sympathetic activity of the autonomous nervous system in standing posture. An improvement in predictability during controlled breathing appears to be due to the introduction of a periodic component. (C) 2000 published by Elsevier Science B.V.

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In the present article, slag foaming phenomenon under dynamic conditions is critically analyzed on the basis of the results of high-temperature X-ray image analysis experiments. The results indicate that the mismatch between the gas generation rate and gas escape rate has a serious impact on the foam height. This mismatch is attributed to the chemical reaction rate, which has to be considered in modeling slag foaming under dynamic conditions. The results further imply that a critical ratio of bubble size/crucible size exists, where wall effects are likely to become prominent.

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This study addresses the issues of spatial distribution, dispersal, and genetic heterogeneity in social groups of the cellular slime molds (CSMs). The CSMs are soil amoebae with an unusual life cycle that consists of alternating solitary and social phases. Because the social phase involves division of labor with what appears to be an extreme form of "altruism", the CSMs raise interesting evolutionary questions regarding the origin and maintenance of sociality. Knowledge of the genetic structure of social groups in the wild is necessary for answering these questions. We confirm that CSMs are widespread in undisturbed forest soil from South India. They are dispersed over long distances via the dung of a variety of large mammals. Consistent with this mode of dispersal, most social groups in the two species examined for detailed study, Dictyostelium giganteum and Dictyostelium purpureum, are multi-clonal.