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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The metabolism of methyl methanesulphonate

Pillinger, David J. January 1964 (has links)
Methyl methanesulphenate has been prepared labelled with radioactive carbon and its metabolism studied in rat, mouse and rabbit. The distribution of the drug after injection has been determined in the rat. Quantitative studies in this species have shown that less than as % of the injected drug is excreted or exhaled in 24 hours. Assay of tissue levels of radioactivity after injection has confirmed that the majority of the drug remains bound within the animal body. In the rat, the principal metabolic reaction has been shown to take place in the liver with glutathione. The S-methylglutathione formed is excreted in bile and this intermediate was the source of the urinary metabolites. In the urine, conjugates of S-methylcyateine and S-methylthioglycollic acid, together with small quantities of radioactive urea, have been recognized. The main metabolite has not been identified but appears to be a substituted guanidine compound. The possible significance of these results of these results has been discussed in terms of sell biochemistry.
2

Multicolour photometry of globular cluster stars

Pike, Christopher David January 1977 (has links)
The underlying theme of this thesis is the application of electronography to the study of stars in globular clusters through the use of both broad and intermediate-band photometric systems. Introductions to both the study of globular clusters and to the use of electronography are given in Chapter 1. In Chapters 2 and 3 observations based upon electronographic exposures are presented for two little-studied clusters, NGC 5053 and NGC 6366. Both are loose, sparsely populated clusters but despite their similarity in appearance, the photometry shows that NGC 5053 is an unreddened, metal-poor globular, while NGC 6366 is found to be a highly reddened metal-rich cluster. One variable star in NGC 6366 is shown to be an a-type RR Lyrae - an unusual occurrence in a cluster of high metallicity. Chapter 4 describes developments in the reduction of stellar electronographs made by the author. An automatic method of fitting Gaussian profiles to the density volumes is shown to produce photometry as accurate and linear as previous manual techniques, but with a much increased efficiency. This work is extended to investigate the use of more flexible profiles which are then shown to be useful for allowing photometry of crowded images. Finally, an application of the Gaussian profile fitting routines to photographic stellar photometry is discussed. Chapter 5 reports the use of this reduction scheme on photographic plates of the globular cluster M 15. Using the David Dunlap Observatory (DDO) intermediate-band photometric system, cluster members are easily distinguished from foreground dwarfs. Chapter 6 describes the results of a programme of DDO electronography of the globular clusters M 5 and M 13. An accuracy of 0.03 is obtained for the DDO colours which, although comparable with some earlier photoelectric work, shows that, with the observational and reduction techniques employed, electronographic stellar photometry has not yet attained its potential as two-dimensional photoelectric photometry.
3

Trial and error and the idea of progress

Pirie, Madsen January 1973 (has links)
No description available.
4

A vindication of logical necessity against scepticism

Philie, Patrice January 2002 (has links)
Some philosophers dispute the claim that there is a notion of logical necessity involved in the concept of logical consequence. They are sceptical about logical necessity. They argue that a proper characterisation of logical consequence - of what follows from what - need not and should not appeal to the notion of necessity at all. Quine is the most prominent philosopher holding such a view. In this doctoral dissertation, I argue that scepticism about logical necessity is not successful. Quine's scepticism takes three forms. Firstly, he is often interpreted as undermining, in his classic paper 'Two Dogmas of Empiricism', the very intelligibility of notions such as meaning, necessity, and analyticity. If the notion of necessity is meaningless, it is clear that ascriptions of logical necessity are also meaningless. In the thesis, I defend Quine's criticism of these notions by situating it in its historical context and emphasising that the real target in those writings is not the intelligibility of these notions as such, but only their Platonistic interpretation. I agree with Quine that a good theory about meaning, necessity, or analyticity must avoid such an ontological commitment. Secondly, Quine advocates, in the same paper, a holistic picture of knowledge and claims that in this picture, ascriptions of logical necessity are superfluous. I then show that holism a la Quine is committed to admit the necessity of statements of logical consequence. Thirdly, there is Quine's substitutional account of logical consequence (as exposed in his (1970)). He contends that this theory makes no use of logical necessity, thus showing its superfluousness. I show that any plausible account of logical consequence needs to appeal to logical necessity, thus undercutting Quine's claim - and, more generally, undercutting scepticism about logical necessity.
5

'Western non-interpolations' and related phenomena in the Gospels

Philipose, John January 1975 (has links)
This thesis is a critique of the theory of Western non-interpolations' propounded by Westcott and Hort, the famous British scholars in the Introduction to their critical edition of the Greek New Testament, 1881. The theory concerns eight cruces interpretum in the concluding section of Luke's Gospel and one in the last but one chapter of Matthew's Gospel. The eight Lukan passages, though missing from Codex Bezae (D) and its allies ('Western' family), are read by Codex Vaticanus (B) and Codex Sinaiticus (א) as well as by (p⁷⁵ and) the vast majority of the other ancient witnesses. (The pattern of the textual evidence for the Matthaean passage is rather different, although B and א are ranged against the omission shown by D). In these contexts Westcott-Hort decided to apply the principle of brevior lectio potior. This was indeed a radical departure from their low estimation of the 'Western' group in general vis-a-vis the B א (Alexandrian) group which they idealised as 'neutral' and as having a very high degree of purity. Having once rated the latter so high it was too awkward for our editors to admit that their favourite Text had gone corrupt at those crucial points. Hence they devised the face-saving term 'Western non-interpolations to emphasize that while their characterisation of the 'Western' Text as containing numerous 'interpolations' still held good, in the eight cases listed the 'Western' omissions were to be reckoned as real 'non-interpolations'. This 'writer believes that although Westcott-Hort's intuition regarding the eight passages was correct (except in one instance), the premise from which they started needs to be revised. Omissions of NT texts including the above were caused by various factors. They are confined neither to one family, nor to a single Gospel, nor even to one particular area of a Gospel. Westcott-Hort's inclusion of one Matthaean passage in the above 'classic' (the designation is mine)' category speaks for itself. Moreover, they also called attention to eighteen other ‘Western' ‘omissions' scattered 'across all the Gospels although they attached only a secondary degree of suspicion to the longer texts. I submit that it was our editors' creation of this subtle distinction between these two categories of readings, as also their exaggerated delineation of the 'purity' of the Alexandrian family as against the 'Western' that has given rise to various other theories regarding the editorial vicissitudes of the Third Gospel. In my first volume I examine the twenty-seven passages in question and conclude that out of the eighteen 'non-classic' ones, at least five in Mt represent genuine omissions. In volume II, seven other passages where Westcott-Hort detected the characteristic tendency of 'Western' witnesses, viz., that of 'expansion', are examined. Of these I recommend two for full reinstatement, two for partial reinstatement arid a fifth one for full reinstatement, though not in its traditional position. If these findings have any credibility, then Westcott-Hort's depiction of the 'Western' Text was indeed a gross exaggeration as far as the Gospels are concerned. The Methdology of this thesis consists in a judicious application of the 'eclectic' principle. Each passage is studied on its own merits under three main heads: 1. External Evidence (Inferences to be drawn from MS data). 2. Internal Evidence: a) Transcriptional Probability (The possible attitude of a scribe in inserting or rejecting a passage as the case may be; also the probabilities of accident behind a reading). b) Intrinsic Probability (Considerations such as vocabulary, style and theological propensity of an author; also his general handling of his sources. In fact the application of the principles of Source Criticism, Form Criticism and Redaction Criticism in deciding whether a reading suits its context or not). 3. Conclusion: It is emphasised that the External Evidence is to be carefully balanced against the Internal Evidence in establishing the authenticity or otherwise of a given text rather than reading one's pre-conceived notions into it. The contributions of outstanding commentators and textual critics over the span of about 90 years since Westcott-Hort's time have been critically examined in drawing the inferences of each section. The concluding chapter which is a summation of the above inference serves to highlight the fallacy of Westcott-Hort's pre-suppositions and of certain subsidiary theories and demonstrates why the theory, of' Western non-interpolations' should be discarded as a principle of Textual Criticism.
6

Confinement of multiply charged ions in an ECRH mirror plasma

Petty, Clinton Craig January 1989 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1989. / "DOE/ET-51013-271." / Includes bibliographical references. / Supported by the U.S. Department of Energy. DE-ACO2-78ET51013 / Clinton Craig Petty. / Ph.D.
7

Concentração inibitória mínima de extratos brutos produzidos por actinobactérias para agentes causadores de mastite bovina / Minimum inhibitory concentration of crude extracts from actinomycetes for mastitis pathogens

Leite, Renata de Freitas 08 September 2016 (has links)
O uso imprudente de antibióticos para o tratamento da mastite bovina pode levar ao aumento da resistência bacteriana e ao comprometimento da eficácia dos tratamentos atuais. Desta maneira, novas alternativas para o tratamento da mastite devem ser procuradas. As actinobactérias são capazes de produzir extratos brutos que contêm metabólitos secundários ativos, que inibem o crescimento de outras bactérias. Portanto, o presente estudo teve como objetivo avaliar a concentração inibitória mínima (CIM) de extratos brutos de actinobactérias para isolados de Staphylococcus aureus, Staphylococcus chromogenes, Streptococcus dysgalactiae e Streptococcus uberis, provenientes de 23 rebanhos leiteiros. Estes isolados foram identificados pela cultura microbiológica e por espectrometria de massas. Assim, foi realizada uma triagem, pelo bioensaio colorimétrico, de 15 extratos brutos, previamente testados e identificados, provenientes de actinobatérias isoladas de diferentes ambientes e plantas (caatinga, áreas de reflorestamento e do eucalipto) para 10 isolados de cada espécie causadora de mastite. Em seguida, os extratos Caat 1-54 e Caat P5-8 foram selecionados para determinação da CIM, a 50% (CIM50) e a 90% (CIM90). Para determinar a CIM dos extratos brutos, foram utilizados 20 isolados de cada espécie, totalizando 80 isolados. Foi utilizada a análise de sobrevivência para avaliação dos resultados. O extrato Caat 1-54 apresentou os menores valores de CIM50 e CIM90 para S. aureus (0,39 µg/mL e 6,25 µg/mL, respectivamente) e S. chromogenes (CIM50 = CIM90 = 0,78 µg/mL). O ceftiofur apresentou os menores valores de CIM tanto para Strep. dysgalactiae (CIM50 ≤ 0,048 µg/mL; CIM90 = 100 µg/mL), como para Strep. uberis (CIM50 ≤ 0,19 µg/mL; CIM90 = 0,39 µg/mL). Seguido do ceftiofur, o extrato Caat 1-54 foi o que apresentou menores valores CIM, com apenas uma diluição seriada de diferença entre as CIM50 das duas espécies (1,56 e 0,78 µg/mL para Strep. dysgalactiae e Strep. uberis, respectivamente). O extrato Caat P5-8 apresentou os maiores valores de CIM50 e CIM90 para todas as espécies estudadas (CIM ≥ 25 µg/mL). Os resultados obtidos indicam o potencial dos extratos brutos provenientes de actinobactérias para o tratamento da mastite bovina causada por S. aureus, S. chromogenes, Strep. dysgalactiae e Strep. uberis / The reckless use of antibiotics for the treatment of bovine mastitis can increase bacterial resistance and harm the effectiveness of current treatments. Thus, new alternatives for mastitis treatment must be searched. Actinomycetes are capable to produce crude extracts with secondary active metabolites that inhibit the growth of other bacteria. Therefore, the aim of this study was to evaluate the minimum inhibitory concentration (MIC) of crude extracts obtained from actinomycetes for Staphylococcus aureus, Staphylococcus chromogenes, Streptococcus dysgalactiae and Streptococcus uberis isolated from 23 dairy herds. These bacteria were identified by microbiology culture and mass spectrometry. Thus, the colorimetric bioassay was performed. In this screening 15 crude extracts previously tested and identified, obtained from actinomycetes from different Brazilian environments and plants (caatinga, reforestation areas and eucalyptus) were used for 10 isolates of each mastitis pathogens species. Then the Caat 1-54 and Caat P5-8 extracts were selected to the MIC 50% (MIC50) and 90% (MIC90) determination. Twenty mastitis pathogens isolates of each bacteria species were used. Survival analysis was used to evaluate the results. Caat 1-54 extract presented the lowest values of MIC50 e MIC90 for S. aureus (0.39 µg/mL and 6.25 µg/mL, respectively) and S. chromogenes (MIC50 = MIC90 = 0.78 µg/mL). On the other hand, ceftiofur presented the lowest MIC values for both Strep. dysgalactiae (MIC50 ≤ 0.048 µg/mL; MIC90 = 100 µg/mL) and Strep. uberis (MIC50 ≤ 0.19 µg/mL; MIC90 = 0.39 µg/mL). After ceftiofur, Caat 1-54 presented the highest efficiency against Strep. dysgalactiae and Strep. uberis and MIC50 for both species differed by only one serial dilution (1.56 e 0.78 µg/mL for Strep. dysgalactiae and Strep. uberis, respectively). Caat P5-8 extract presented the highest MIC50 and MIC90 values for all pathogens (MIC ≥ 25 µg/mL). Results indicated the potential of crude extracts from actinomycetes to treat bovine mastitis caused by S. aureus, S. schromogenes, Strep. dysgalactiae and Strep. uberis
8

Concentração inibitória mínima de extratos brutos produzidos por actinobactérias para agentes causadores de mastite bovina / Minimum inhibitory concentration of crude extracts from actinomycetes for mastitis pathogens

Renata de Freitas Leite 08 September 2016 (has links)
O uso imprudente de antibióticos para o tratamento da mastite bovina pode levar ao aumento da resistência bacteriana e ao comprometimento da eficácia dos tratamentos atuais. Desta maneira, novas alternativas para o tratamento da mastite devem ser procuradas. As actinobactérias são capazes de produzir extratos brutos que contêm metabólitos secundários ativos, que inibem o crescimento de outras bactérias. Portanto, o presente estudo teve como objetivo avaliar a concentração inibitória mínima (CIM) de extratos brutos de actinobactérias para isolados de Staphylococcus aureus, Staphylococcus chromogenes, Streptococcus dysgalactiae e Streptococcus uberis, provenientes de 23 rebanhos leiteiros. Estes isolados foram identificados pela cultura microbiológica e por espectrometria de massas. Assim, foi realizada uma triagem, pelo bioensaio colorimétrico, de 15 extratos brutos, previamente testados e identificados, provenientes de actinobatérias isoladas de diferentes ambientes e plantas (caatinga, áreas de reflorestamento e do eucalipto) para 10 isolados de cada espécie causadora de mastite. Em seguida, os extratos Caat 1-54 e Caat P5-8 foram selecionados para determinação da CIM, a 50% (CIM50) e a 90% (CIM90). Para determinar a CIM dos extratos brutos, foram utilizados 20 isolados de cada espécie, totalizando 80 isolados. Foi utilizada a análise de sobrevivência para avaliação dos resultados. O extrato Caat 1-54 apresentou os menores valores de CIM50 e CIM90 para S. aureus (0,39 µg/mL e 6,25 µg/mL, respectivamente) e S. chromogenes (CIM50 = CIM90 = 0,78 µg/mL). O ceftiofur apresentou os menores valores de CIM tanto para Strep. dysgalactiae (CIM50 ≤ 0,048 µg/mL; CIM90 = 100 µg/mL), como para Strep. uberis (CIM50 ≤ 0,19 µg/mL; CIM90 = 0,39 µg/mL). Seguido do ceftiofur, o extrato Caat 1-54 foi o que apresentou menores valores CIM, com apenas uma diluição seriada de diferença entre as CIM50 das duas espécies (1,56 e 0,78 µg/mL para Strep. dysgalactiae e Strep. uberis, respectivamente). O extrato Caat P5-8 apresentou os maiores valores de CIM50 e CIM90 para todas as espécies estudadas (CIM ≥ 25 µg/mL). Os resultados obtidos indicam o potencial dos extratos brutos provenientes de actinobactérias para o tratamento da mastite bovina causada por S. aureus, S. chromogenes, Strep. dysgalactiae e Strep. uberis / The reckless use of antibiotics for the treatment of bovine mastitis can increase bacterial resistance and harm the effectiveness of current treatments. Thus, new alternatives for mastitis treatment must be searched. Actinomycetes are capable to produce crude extracts with secondary active metabolites that inhibit the growth of other bacteria. Therefore, the aim of this study was to evaluate the minimum inhibitory concentration (MIC) of crude extracts obtained from actinomycetes for Staphylococcus aureus, Staphylococcus chromogenes, Streptococcus dysgalactiae and Streptococcus uberis isolated from 23 dairy herds. These bacteria were identified by microbiology culture and mass spectrometry. Thus, the colorimetric bioassay was performed. In this screening 15 crude extracts previously tested and identified, obtained from actinomycetes from different Brazilian environments and plants (caatinga, reforestation areas and eucalyptus) were used for 10 isolates of each mastitis pathogens species. Then the Caat 1-54 and Caat P5-8 extracts were selected to the MIC 50% (MIC50) and 90% (MIC90) determination. Twenty mastitis pathogens isolates of each bacteria species were used. Survival analysis was used to evaluate the results. Caat 1-54 extract presented the lowest values of MIC50 e MIC90 for S. aureus (0.39 µg/mL and 6.25 µg/mL, respectively) and S. chromogenes (MIC50 = MIC90 = 0.78 µg/mL). On the other hand, ceftiofur presented the lowest MIC values for both Strep. dysgalactiae (MIC50 ≤ 0.048 µg/mL; MIC90 = 100 µg/mL) and Strep. uberis (MIC50 ≤ 0.19 µg/mL; MIC90 = 0.39 µg/mL). After ceftiofur, Caat 1-54 presented the highest efficiency against Strep. dysgalactiae and Strep. uberis and MIC50 for both species differed by only one serial dilution (1.56 e 0.78 µg/mL for Strep. dysgalactiae and Strep. uberis, respectively). Caat P5-8 extract presented the highest MIC50 and MIC90 values for all pathogens (MIC ≥ 25 µg/mL). Results indicated the potential of crude extracts from actinomycetes to treat bovine mastitis caused by S. aureus, S. schromogenes, Strep. dysgalactiae and Strep. uberis
9

Stabilité et coloration des graphes sans P5 / Independent sets and coloring in P5-free graphs

Morel, Gregory 30 September 2011 (has links)
La classe des graphes sans P5, c'est-à-dire des graphes ne contenant pas de chaîne induite à cinq sommets, est d'un intérêt particulier en théorie des graphes. Il s'agit en effet de la plus petite classe définie par un seul sous-graphe connexe interdit pour laquelle on ignore encore s'il existe un algorithme polynomial permettant de résoudre le problème du stable maximum. Or ce problème, dont on sait qu'il est difficile en général, est d'une grande importance en pratique (problèmes de planification, d'allocation de registres dans un processeur, biologie moléculaire...). Dans cette thèse, nous commençons par dresser un état de l'art complet des méthodes utilisées pour résoudre le problème dans des sous-classes de graphes sans P5, puis nous étudions et résolvons ce problème dans une sous-classe particulière, la classe des graphes sans P5 3-colorables. Nous apportons également des solutions aux problèmes de la reconnaissance et de la coloration de ces graphes, chaque fois en temps linéaire. Enfin, nous définissons, caractérisons et sommes capables de reconnaître les graphes "chain-probe", qui sont les graphes auxquels il est possible de rajouter des arêtes entre certains sommets de sorte qu'ils soient bipartis et sans P5. Les problèmes de ce type proviennent de la génétique et ont également des applications en intelligence artificielle. / The class of P5-free graphs, namely the graphs without induced chains with five vertices, is of particular interest in graph theory. Indeed, it is the smallest class defined by only one forbidden connected induced subgraph for which the complexity of the Maximum Independent Set problem is unknown. This problem has many applications in planning, CPU register allocation, molecular biology... In this thesis, we first give a complete state of art of the methods used to solve the problem in P5-free graphs subclasses; then we study and solve this problem in a particular subclass, the class of 3-colorable P5-free graphs. We also bring solutions to recognition and coloring problems of these graphs, each time in linear time. Finally, we define, characterize, and are able to recognize "chain-probe" graphs, namely the graphs for which we can add edges between particular vertices such that the resulting graph is bipartite and P5-free. Problems of this type come from genetics and have application in I.A.
10

Creative Coding on the Web in p5.js : A Library Where JavaScript Meets Processing

Sandberg, Emil January 2019 (has links)
Creative coding is the practice of writing code primarily for an expressive purpose rather than a functional one. It is mostly used in creative arts contexts. One of the most popular tools in creative coding is Processing. Processing is a desktop application and in recent years a web-based alternative named p5.js has been developed. This thesis investigates the p5.js JavaScript library. It looks at what can be accomplished with it and in which cases it might be used. The main focus is on the pros and cons of using p5.js for web graphics. Another point of focus is on how the web can be used as a creative platform with tools like p5.js. The goals are to provide an overview of p5.js and an evaluation of the p5.js library as a tool for creating interactive graphics and animations on the web. The research focuses on comparing p5.js with plain JavaScript from usability and performance perspectives and making general comparisons with other web-based frameworks for creative coding. The methods are a survey and interviews with members of creative coding communities, as well as performing coding experiments in p5.js and plain JavaScript and comparing the results and the process. The results from the coding experiments show that compared to plain JavaScript p5.js is easier to get started with, it is more intuitive, and code created in p5.js is easier to read. On the other hand, p5.js performs worse, especially when continuously drawing large amounts of elements to the screen. This is further supported by the survey and the interviews, which show that p5.js is liked for its usability, but that its performance issues and lack of advanced features mean that it is usually not considered for professional projects. The primary use case for p5.js is creating quick, visual prototypes. At the same time, the interviews show that p5.js has been used in a variety of contexts, both creative and practical. p5.js is a good library for getting started with coding creatively in the browser and is an excellent choice for experimenting and creating prototypes quickly. Should project requirements be much more advanced than that, there might be other options that will work better.

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