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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.
81

New Rituals : Materials, Objects and Space

Madanska, Dessislava January 2020 (has links)
My project unfolds on three different scales:  Materials, Objects and a Space. A research on materials and new technique for their transformation, a creation of functional objects out of the transformed materials, and finally, a spatial environment for the created objects. Real-life site visits to various factories and craftsmen, discussions with makers, sourcing leftover materials, transforming materials into borderline art/design objects are among the key elements of my research methodology.  The three scales of my work are unified by the notion of Rituals. My understanding of rituals is not about creating a new religion but focuses rather on the activities in our everyday that can become rituals. It is about finding magic in the mundane. Daily routines and rituals are one of the main things that can keep us grounded, especially in a time of crisis. I believe that material explorations and working with the senses are important and relevant for the field of Spatial design and that my approach to engaging different scales within the project brings something new and yet not vastly explored.
82

Évaluation de la biomasse fongique dans les systèmes de ventilation

Biyeyeme Bi Mve, Marie Jeanne 12 1900 (has links)
Le nettoyage des systèmes de Chauffage, Ventilation et Climatisation de l’Air est important pour assurer une bonne qualité d’air intérieur. Le déclenchement de leur nettoyage est basé sur une inspection visuelle qui ne tient pas compte du contenu en moisissures, lesquelles ont des effets sur le système respiratoire. Cette recherche vise à proposer une méthode d’évaluation du contenu en moisissures afin d’aider les gestionnaires d’immeuble. Cinq générations de poussières ont été effectuées pour simuler un conduit de ventilation. Une cassette modifiée 37 mm et un filtre CPV pré-pesés ont utilisés pour collecter les poussières déposées avec une pompe calibrée à 15L/min. Les pourcentages de collecte des cassettes et des filtres ont été calculés pour 54 échantillons. Dix générations supplémentaires de poussières ont été effectuées concomitamment avec la génération de spores. Soixante échantillons ont été analysés selon quatre méthodes : culture, comptage direct des spores par microscopie (CDSM), dosage de β-N-acétylhexosaminidase (NAHA), 18S-q-PCR. La limite de détection (LD), la réplicabilité, la répétabilité, le nombre de spores et le coefficient de corrélation (r) ont été déterminés. Les récupérations de poussières étaient supérieures à 84%. Selon la méthode analytique, les concentrations médianes de spores/100 cm² allaient de 10 000 à 815 000. Les LD variaient dépendamment de la méthode de 120 à 218 000 spores/100 cm² et r de -0,08 à 0,83. La réplicabilité et la répétabilité étaient de 1% et 1% pour PCR; 5% et 10% pour CDSM; 6% et 15% pour NAHA; 12% et 11% pour culture. La méthode de collecte a démontré une excellente efficacité de récupération. La PCR est la méthode analytique recommandée pour l’évaluation fongique des systèmes de ventilation. Une validation terrain est en cours. / Cleaning systems for Heating Ventilation and Air Conditioning is important to ensure good indoor air quality. The outbreak of their cleaning is based on a visual inspection does not take into account the content molds, which have effects on the respiratory system. This research aims at providing a mold content of the assessment methodology to help building managers. Five dust generations were made in an exposition chamber mimicking a HVAC duct system. A modified 37-mm cassette with a pre-weighed PVC filter was used to collect the settled dust at a flow rate of 15L/min. Particles recovery percentages collected by the cassettes and those deposited on the filters were calculated for 54 samples. Ten other generations were performed with dust using different levels of mold spores. Sixty samples were analyzed with four methods : culture on Malt Extract Agar, direct microscopic spores count (DMSC), Beta-N-Acetylhexosaminidase assay (NAHA) and 18S-q-PCR assay. The detection limit (DL), replicability, repeatability, the number of spores and correlation coefficient (r) were determined. The recovery percentages were greater than 84%. According methods, the median concentration of spores/100 cm² ranged from 10,000 to 815,000. The DL varies depending on the method from 120 to 218,000 spores/100 cm² and from -0.08 to 0.83. Replicability and repeatability were 1% and 1% for PCR, 5% and 10% for DMSC, 6% and 11% for NAHA, 12% and 11% for culture. The sampling method showed excellent dust collection efficiency. The PCR method is recommended for fungal evaluation of ventilation systems. A field validation is underway.
83

Estudo das propriedades do açúcar líquido invertido processado com radiação gama e feixe de elétrons / Study of the properties of inverted liquid sugar processed with gamma radiation and electron beam

Podadera, Priscilla 27 February 2007 (has links)
O Brasil ocupa posição de destaque no mercado de açúcar a granel e consumo elevado deste ingrediente na forma líquida, em especial pelas indústrias de bebidas e alimentos. O açúcar líquido apresenta vantagens em relação ao açúcar a granel como facilidade do manuseio e dosagem, espaço reduzido para a armazenagem, redução das perdas, custos e mão-de-obra, melhora na sanitização e grande variação possível nas proporções de diferentes misturas de açúcares. O açúcar Uquido invertido é uma solução de sacarose, glicose e frutose em água e recebe esse nome porque durante a sua produção há a inversão do poder óptico de rotação da solução. No processo produtivo do açúcar invertido existem alguns pontos que podem gerar a contaminação por microrganismos, dessa forma torna-se importante o desenvolvimento de técnicas que propiciem a sanitização eficiente desta matéria-prima. Este trabalho estudou duas técnicas alternativas de controle microbiano: a radiação gama com fonte de cobalto-60 e a radiação com feixe de elétrons. O estudo foi conduzido nas doses de 5, 10, 20, 30 e 50 kGy. O teor de sacarose apresentou decréscimo com a radiação indicando que ocorreu a quebra da ligação glicosídica com a formação de glicose e fioitose, gerando o aumento do teor de sólidos solúveis. Ocorreu a formação de compostos ácidos, confirmado pela redução de pH, que foi proporcional ao aumento da dose de radiação. As maiores doses provocaram alterações na cor do xarope pela formação de polímeros com cadeia molecular longa. A viscosidade nas amostras irradiadas com radiação gama aumentou em relação ao controle, indicando a prevalência de polimerização das moléculas, enquanto que na radiação com feixe de elétrons a polimerização foi observada somente na amostra que recebeu a dose de 50 kGy. Na análise sensorial, os julgadores apontaram diferença significativa (5%) no sabor entre o controle e as amostras irradiadas com 5 kGy, nas duas técnicas de processamento. Não foi possível identificar o efeito da radiação gama no controle de bolores e leveduras. / Brazil occupies position of prominence in the sugar market and high consumption of this ingredient in the liquid form, in special for the beverages and food industries. The liquid sugar presents advantages in relation to the bulk granulated system such as easiness of the handling and dosage, reduced space for the storage, reduction of the losses, costs and hand of workmanship, improvement of the sanitizing and great possible variation in the ratios of different mixtures of sugars. The inverted liquid sugar is a solution of sucrose, glucose and fructose in water. This ingredient receives this name because during its production it has an inversion of the optic power of rotation of the solution. In the productive process of the inverted sugar some points occur that can generate contamination by microorganisms, so its become important the development of techniques that propitiate the efficient sanitizing of this raw material. This work aims at to consider two alternative techniques of microbiologic control: gamma radiation with source of cobalto-60 and radiation with electron beam. The study was lead in the doses of 5, 10, 20, 30 and 50 kGy. Concentration of sucrose presented in syrup decreased with the radiation indicating the scission of glicosidic linkage in addition with the glucose and fiaictose formation, generating the increase in solids soluble. The acid compounds formation occurred, confirmed by the reduction of pH, that it was proportional with the increase of the radiation dose. The biggest doses had provoked change of color in the syrup by the long molecular chain polymers formation. Viscosity in the samples processed by gamma radiation increased in relation to the control, indicating the prevalence of polymerization of molecules, whereas in the radiation with electron beam the polymerization was only observed in the sample that received the dose of 50 kGy, In the sensorial analysis, the judges had pointed significant difference (5%) in the flavor among control and the samples radiated with 5 kGy in the two techniques of processing. The alterations provoked for the irradiation had not been enough to provide significant changes in the inverted sugar, even in the highest dose of 50 kGy. It was not possible to identify the effect of gamma radiation in the control of molds and yeasts.
84

Business review and strategic plan for a small plastic mould making shop in Hong Kong.

January 1994 (has links)
by Ngan Chi-Cheung. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 124-125). / ABSTRACT --- p.i / TABLE OF CONTENTS --- p.iii / ACKNOWLEDGEMENTS --- p.viii / CHAPTER / Chapter I. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Initiation of the Project --- p.1 / Chapter 1.2 --- Objectives --- p.2 / Chapter 1.3 --- Arrangement of the Report --- p.3 / Chapter II. --- METHODOLOGY --- p.5 / Chapter 2.1 --- Scope --- p.5 / Chapter 2.2 --- Approaches --- p.5 / Chapter 2.3 --- Studying Steps --- p.7 / Chapter 2.3.1 --- Market Research --- p.7 / Chapter 2.3.2 --- Financial Analysis --- p.8 / Chapter 2.3.3 --- SWOT Analysis --- p.9 / Chapter 2.3.4 --- Problems and Difficulties Identification --- p.9 / Chapter 2.3.5 --- Strategic Plan Formulation --- p.9 / Chapter III. --- PLASTIC MOULD MAKING INDUSTRY IN HONG KONG / Chapter 3.1 --- Product Profile --- p.11 / Chapter 3.1.1 --- Product Range across the whole Mould Making Industry --- p.11 / Chapter 3.1.2 --- Manufacturing Process --- p.12 / Chapter 3.2 --- Market Profile --- p.13 / Chapter 3.2.1 --- The Mould Market as a Whole --- p.13 / Chapter 3.2.2 --- Plastic Mould Market Profile --- p.15 / Chapter 3.3 --- Customer Profile --- p.16 / Chapter 3.3.1 --- End-User Group --- p.16 / Chapter 3.3.2 --- Customer Group --- p.17 / Chapter 3.3.2 --- Domestic Customer Needs --- p.19 / Chapter 3.4 --- Competitor Profile --- p.20 / Chapter 3.4.1 --- Domestic Competition --- p.20 / Chapter 3.4.2 --- Foreign Competition --- p.22 / Chapter 3.5 --- Distribution Profile --- p.25 / Chapter 3.5.1 --- Maintenance and Acquisition of Customers --- p.25 / Chapter 3.5.2 --- Order Taking --- p.26 / Chapter 3.6 --- Outlook of the Industry --- p.27 / Chapter 3.6.1 --- Plastics Industry --- p.27 / Chapter 3.6.2 --- Plastic Mould Making Industry --- p.29 / Chapter IV. --- THE SMALL PLASTIC MOULD MAKING SHOP --- p.32 / Chapter 4.1 --- Background of the Small Business --- p.32 / Chapter 4.2 --- Company Profile of CL --- p.33 / Chapter 4.2.1 --- Organization Structure --- p.33 / Chapter 4.2.2 --- Management --- p.34 / Chapter 4.2.3 --- Assets --- p.36 / Chapter 4.2.4 --- Staffing --- p.37 / Chapter 4.3 --- Product Profile of CL --- p.40 / Chapter 4.4 --- Customer Profile of CL --- p.41 / Chapter 4.5 --- Competitor Profile of CL --- p.42 / Chapter V. --- PROBLEM IDENTIFICATION FOR CL --- p.44 / Chapter 5.1 --- Financial Analysis --- p.44 / Chapter 5.1.1 --- Simplifications and Assumptions --- p.44 / Chapter 5.1.2 --- Cash Flow Statements --- p.46 / Chapter 5.1.3 --- Income Statements --- p.49 / Chapter 5.1.4 --- Retained Earnings Statements and Balance Sheets --- p.50 / Chapter 5.1.5 --- Ratio Analysis --- p.51 / Chapter 5.1.6 --- Comparison with Industrial Financial Data --- p.54 / Chapter 5.2 --- SWOT Analysis --- p.56 / Chapter 5.2.1 --- Strengths --- p.56 / Chapter 5.2.2 --- Weaknesses --- p.59 / Chapter 5.2.3 --- Opportunities --- p.63 / Chapter 5.2.4 --- Threats --- p.67 / Chapter VI. --- STRATEGIC PLAN FOR CL --- p.71 / Chapter 6.1 --- An overview of CL --- p.71 / Chapter 6.2 --- Future Growth of CL --- p.73 / Chapter 6.3 --- Business Objectives --- p.74 / Chapter 6.4 --- Strategic Plan --- p.74 / Chapter 6.4.1 --- Financial Strategies --- p.76 / Chapter 6.4.2 --- Management Strategies --- p.79 / Chapter 6.4.3 --- Product Strategies --- p.85 / Chapter 6.4.4 --- Production Strategies --- p.86 / Chapter 6.4.5 --- Marketing Strategies --- p.88 / Chapter 6.4.6 --- Implementation Schedule --- p.90 / Chapter VII. --- LESSONS LEARNED --- p.91 / Chapter 7.1 --- Market Information and Industry Data --- p.91 / Chapter 7.2 --- Decision Making --- p.92 / Chapter 7.3 --- Management Practices --- p.92 / Chapter 7.4 --- Simple and easy to implement strategies --- p.93 / Chapter 7.5 --- Reliance on key Employees --- p.93 / Chapter 7.6 --- Leadership Style --- p.94 / Chapter 7.7 --- Importance of Cash Flows to Small Business --- p.95 / Chapter 7.8 --- Delegation of Duties --- p.96 / Chapter VIII. --- CONCLUSIONS --- p.98 / APPENDIX / Chapter 1. --- EXAMPLE OF ADVERTISEMENT FROM MOULD MAKING SHOP --- p.100 / Chapter 2. --- "MACHINERY, MOULD PRODUCTS AND WORKSHOP ENVIRONMENT OF CL" --- p.101 / Chapter 3. --- PRODUCTION SCHEDULE FOR PLASTIC MOULDS --- p.106 / Chapter 4. --- DISTRIBUTION OF CL'S SALES TO ITS CUSTOMERS … --- p.107 / Chapter 5. --- RECORDED FINANCIAL STATEMENTS OF CL --- p.110 / Chapter 6. --- ANTICIPATED FINANCIAL STATEMENTS OF CL --- p.118 / BIBLIOGRAPHY --- p.124
85

Estudo das propriedades do açúcar líquido invertido processado com radiação gama e feixe de elétrons / Study of the properties of inverted liquid sugar processed with gamma radiation and electron beam

Priscilla Podadera 27 February 2007 (has links)
O Brasil ocupa posição de destaque no mercado de açúcar a granel e consumo elevado deste ingrediente na forma líquida, em especial pelas indústrias de bebidas e alimentos. O açúcar líquido apresenta vantagens em relação ao açúcar a granel como facilidade do manuseio e dosagem, espaço reduzido para a armazenagem, redução das perdas, custos e mão-de-obra, melhora na sanitização e grande variação possível nas proporções de diferentes misturas de açúcares. O açúcar Uquido invertido é uma solução de sacarose, glicose e frutose em água e recebe esse nome porque durante a sua produção há a inversão do poder óptico de rotação da solução. No processo produtivo do açúcar invertido existem alguns pontos que podem gerar a contaminação por microrganismos, dessa forma torna-se importante o desenvolvimento de técnicas que propiciem a sanitização eficiente desta matéria-prima. Este trabalho estudou duas técnicas alternativas de controle microbiano: a radiação gama com fonte de cobalto-60 e a radiação com feixe de elétrons. O estudo foi conduzido nas doses de 5, 10, 20, 30 e 50 kGy. O teor de sacarose apresentou decréscimo com a radiação indicando que ocorreu a quebra da ligação glicosídica com a formação de glicose e fioitose, gerando o aumento do teor de sólidos solúveis. Ocorreu a formação de compostos ácidos, confirmado pela redução de pH, que foi proporcional ao aumento da dose de radiação. As maiores doses provocaram alterações na cor do xarope pela formação de polímeros com cadeia molecular longa. A viscosidade nas amostras irradiadas com radiação gama aumentou em relação ao controle, indicando a prevalência de polimerização das moléculas, enquanto que na radiação com feixe de elétrons a polimerização foi observada somente na amostra que recebeu a dose de 50 kGy. Na análise sensorial, os julgadores apontaram diferença significativa (5%) no sabor entre o controle e as amostras irradiadas com 5 kGy, nas duas técnicas de processamento. Não foi possível identificar o efeito da radiação gama no controle de bolores e leveduras. / Brazil occupies position of prominence in the sugar market and high consumption of this ingredient in the liquid form, in special for the beverages and food industries. The liquid sugar presents advantages in relation to the bulk granulated system such as easiness of the handling and dosage, reduced space for the storage, reduction of the losses, costs and hand of workmanship, improvement of the sanitizing and great possible variation in the ratios of different mixtures of sugars. The inverted liquid sugar is a solution of sucrose, glucose and fructose in water. This ingredient receives this name because during its production it has an inversion of the optic power of rotation of the solution. In the productive process of the inverted sugar some points occur that can generate contamination by microorganisms, so its become important the development of techniques that propitiate the efficient sanitizing of this raw material. This work aims at to consider two alternative techniques of microbiologic control: gamma radiation with source of cobalto-60 and radiation with electron beam. The study was lead in the doses of 5, 10, 20, 30 and 50 kGy. Concentration of sucrose presented in syrup decreased with the radiation indicating the scission of glicosidic linkage in addition with the glucose and fiaictose formation, generating the increase in solids soluble. The acid compounds formation occurred, confirmed by the reduction of pH, that it was proportional with the increase of the radiation dose. The biggest doses had provoked change of color in the syrup by the long molecular chain polymers formation. Viscosity in the samples processed by gamma radiation increased in relation to the control, indicating the prevalence of polymerization of molecules, whereas in the radiation with electron beam the polymerization was only observed in the sample that received the dose of 50 kGy, In the sensorial analysis, the judges had pointed significant difference (5%) in the flavor among control and the samples radiated with 5 kGy in the two techniques of processing. The alterations provoked for the irradiation had not been enough to provide significant changes in the inverted sugar, even in the highest dose of 50 kGy. It was not possible to identify the effect of gamma radiation in the control of molds and yeasts.
86

Occurrence des légionelles dans les eaux thermales tunisiennes et évaluation de l'activité anti-legionella des huiles essentielles de plantes autochtones / Occurence of Legionella in tunisian spas and evaluation of the anti-Legionella activity of essential oils from tunisian plants

Chaftar, Nawel 06 November 2013 (has links)
L'environnement des stations thermales est favorable à la croissance des Legionella. La Tunisie compte de nombreux sites thermaux. Elle a par ailleurs développé une médecine traditionnelle à base de plantes. L'objectif de ce travail était de caractériser des souches de légionelles isolées de stations thermales et d'étudier le potentiel antimicrobien d'HE de plantes tunisiennes. 2 souches de L. londiniensis et 16 de L. pneumophila (sérovars 1, 4, 5, 6 et 8) ont été isolées de 3 stations thermales tunisiennes et avaient des pulsotypes différents de ceux de la base du CNRL. Les HE de 6 plantes tunisiennes ont été extraites, analysées (GC-MS) et testées contre L. pneumophila (8 souches, sérovars 1, 4, 5, 6 et 8). Les HE de Juniperus phoenicea L. (isobornéol 20,91% et 1S α-pinène 18,30%) et Thymus vulgaris (carvacrol 88,50%) étaient les plus actives (CMI <0,03 mg/mL et ≤0,07 mg/mL respectivement). L'activité de 20 HE (6 de plantes tunisiennes et 14 commerciales) a été évaluée contre 11 espèces bactériennes (6 Gram+, 5 Gram-) et 7 fongiques (4 levures, 3 filamenteux). L'HE de T. vulgaris tunisien était la plus active (Gram-: CMI ≤0,34 mg/mL ; Gram+: CMI ≤0,7 mg/mL ; levures: CMI ≤0,55 mg/mL ; moisissures: CMI=0,3 mg/mL ; dermatophytes: CMI ≤0,07 mg/mL). Elle a montré une activité très supérieure à celle de l'HE commerciale de T. vulgaris certainement due à sa composition différente. En conclusion, la présence de Legionella dans les sites étudiés doit encourager les autorités à renforcer les mesures préventives et l'efficacité antimicrobienne des HE, en particulier l'HE de T. vulgaris tunisien, suggère leur possible intérêt dans le traitement des eaux ou la conservation des aliments. / Spa environment is favorable to the growth of Legionella. Tunisia, which has many spa, has developed a traditional herbal medicine. The objective of this work was to characterize strains of Legionella isolated from 3 spas and to investigate the antimicrobial potential of EOs from Tunisian plants.2 strains of L. londiniensis and 16 of L. pneumophila (serotypes 1, 4, 5, 6 and 8) were isolated and had different pulsotypes from those of the CNRL database.EOs from six Tunisian plants were extracted, analyzed (GC-MS) and tested against L. pneumophila (8 strains, serotypes 1, 4, 5, 6 and 8). The EO of Juniperus phoenicea L. (1S isoborneol 20.91% and 18.30% α-pinene) and Thymus vulgaris (carvacrol 88.50%) were the most active (MIC <0.03 mg/mL and ≤0.07 mg/mL, respectively).The activity of 20 EOs (6 from Tunisian plants and 14 commercial ones) was evaluated against 11 bacterial species (6 Gram+, 5 Gram-) and 7 fungal species (4 yeasts, 3 filamentous). The EO of Tunisian T. vulgaris was the most active (Gram-: MIC ≤ 0.34 mg/mL, and Gram +: MIC ≤0.7 mg/mL; yeasts MIC ≤0.55 mg/mL; mold: MIC=0.3 mg/mL; dermatophytes: MIC ≤0.07 mg/mL). It showed a higher activity than the commercial EO of T. vulgaris, certainly due to their different composition.In conclusion, the presence of Legionella in the studied spas should encourage the authorities to strengthen the preventive measures. The antimicrobial efficacy of EOs, especially from Tunisian T. vulgaris, suggest their potential interest in water treatment or food storage.
87

Trade-offs And Social Behaviour In The Cellular Slime Moulds

Sathe, Santosh 10 1900 (has links) (PDF)
By combining laboratory experiments with field work, I have looked at the following aspects of cellular slime mould (CSM) biology: (a) the genetic structure of social groups (fruiting bodies) in the wild and its relation to the role of large mammals as dispersal agents; (b) social behaviour in clonal, intra-species polyclonal and interspecies social groups and (c) fitness-related trade-offs with respect to life history traits as a possible mechanism for coexistence and cooperative behaviour in CSMs. The major findings of this study are as follows: (a) individuals belonging to different strains of a species, different species and genera occur in close proximity, even on a speck of soil (250µm–1mm) or the same dung pat; (b) social groups formed in the wild by Dictyostelium giganteum and D. purpureum are generally multiclonal; (c) genetically diverse strains can co-aggregate and form chimaeric social groups; (d) in chimaeric social groups, strains differ in their relative sporulation efficiencies; (e) the fact that strains co-exist in spite of this may be attributable in part to trade-offs between various fitness-related traits as can be demonstrated in the case of wild isolates of D. giganteum in pair wise mixes. The Dictyostelids or CSMs are haploid, eukaryotic, soil dwelling social amoebae with an unusual life cycle (Bonner, 1967; Raper, 1984). They exist as single cells in the presence of food (bacteria, yeast, fungal spores). Once the food is exhausted, they enter the social phase of their life cycle. Approximately 102 to 106 amoebae aggregate at a common collection point and form a starvation resistant structure called the fruiting body. In many species a fruiting body is made up of an aerial stalk of dead cells and a ball of viable spores on top. In other CSM species (not part of this study), all amoebae in a fruiting body differentiate into spores and the stalk is an extracellular secretion. The CSM life cycle raises fundamental questions related to the evolution of an extreme form of ‘altruism’ in the form of reproductive division of labour in social groups. The spore–stalk distinction in the CSMs is analogous to the germ–soma distinction in metazoans, although, the CSMs achieve multicellularity not by repeated divisions of a zygote but via the aggregation of many cells which may or may not be clonally related (Bonner, 1982; Kaushik and Nanjundiah, 2003). Social behaviour in the CSMs offers interesting parallels to what is seen in the social insects (Gadagkar and Bonner, 1994). The origin and maintenance of ‘altruism’ has been a long-standing issue in sociobiology. Because of their simple life cycle and experimental tractability, the CSMs are ideal for studying the evolutionary origin and maintenance of social behaviour, in particular of ‘altruistic’ behaviour. By elevating spores above soil level, stalk cells, protect them from noxious compounds and predators present in soil and also facilitate their passive dispersal. In the course of doing so they die. The death of stalk cells appears to be an extreme form of altruism. Knowledge of the genetic structure of social groups and populations including patterns of kinship is essential for modelling the evolution of ‘altruism’. Thus, it is important to understand the genetic structure of CSM social groups in the wild. For this, social groups (fruiting bodies) of CSMs were isolated from undisturbed forest soil of the Mudumalai forest reserve in South India. Soil and animal dung samples were brought to the laboratory and quasi-natural social groups were generated by inoculating the samples on non-nutrient agar. The fruiting bodies from various CSM species were formed by these isolates. Since soil and dung samples were not perturbed in any way, the fruiting bodies were formed as they would have in nature. When compared to soil, dung samples contained a higher CSM diversity and more CSM propagules. The presence of CSMs in fresh animal dung makes it likely that they were transported and dispersed over long distances through the gut of these animals. Such dispersal is likely to be preceded by a thorough mixing of spores in the gut. That increases the probability of co-occurrence of different genotypes in a social group. This possibility was confirmed by genetically characterizing spores in social groups of Dictyostelium giganteum and D. purpureum collected from the wild. Random amplification of polymorphic DNA (RAPD), a simple and reliable molecular technique, was used for genotyping spores within a fruiting body. 17 fruiting bodies (8 from animal dung and 9 from soil) were studied. 15 out of 17 (9 out of 11 of D. giganteum and 6 out of 6 D. purpureum) were polyclonal; the minimum number of distinct clones in a single fruiting body was 3 to 7 (animal dung) and 1 to 9 (soil). Therefore in D.giganteum and D. purpureum, chimaeric social groups seem to be the norm. This suggests that other species of CSMs form intra-species chimaeric social groups in wild, though clonal fruiting bodies occur too. The next objective of this thesis was to test whether genetic heterogeneity had functional consequences. That is, when different strains come together in an aggregate, do they contribute equally to the reproductive (spore) and non-reproductive (stalk) pathways? Amoebae of different clones (strains) of D. giganteum or D. purpureum were mixed and developed together and the number of spores formed by each strain was counted. These experiments confirmed that strains of D. giganteum or D. purpureum can aggregate together and form chimaeric fruiting bodies. The ability to mix (measured as the frequency of chimaerism) depended on the strains used and varied from one mix to another. One strain was often found to ‘exploit’ the other during sporulation, that is, it formed more spores than its expected share. Despite this, strains are found in very close proximity in the soil, which raises an important question: when one strain is more efficient at sporulating than other, how can the two co-exist stably? To investigate what might lie behind the stable co-existence of strains, I studied various fitness-related traits in the life cycle of D. giganteum. They included the rate of cell division, the time taken to go through multicellular development, the efficiency of slug migration through various depths of soil and the probability of differentiation into a spore. Measurements were carried out on strains taken separately and on their pair wise mixes. Five different D. giganteum wild strains (46a3, 46d2, 48.1a1, F5 and F16) were used. All were isolated from the Mudumalai forest (India). 46a3 and 46d2 came from soil within 10 cm of each other, 48.1a1 from soil about 200m away from 46a3; and F5 and F16 from the same fruiting body (Kaushik et al., 2006; Sathe et al., 2010). Members of a pair differed significantly in the measured fitness-related traits. For example, in the case of 48.1a1 and 46d2, 48.a1 grew faster than 46d2 both individually and in a mix. After starvation, 48.1a1 formed fruiting bodies faster than 46d2; a mix of the two developed at the rate of the faster member, implying that the slower one (46d2) gained from the association with 48.1a1. During slug migration, slugs formed by 48.1a1 came up through a higher depth of soil than 46d2 slugs and did so earlier. Chimaeric slugs were like the more efficient member, 48.1a1, in terms of the maximum depth of soil that was covered, but like the less efficient member, 46d2, in terms of the time taken for slugs to be seen on the soil surface. 48.1a1 seems to have an advantage over 46d2 in all these respects. However, during sporulation in chimaeras, 48.1a1 formed relatively fewer spores than 46d2. Similar trade-offs were seen in all mixes. F5 and F16 displayed an unexpected feature during sporulation; the spore-forming efficiency of either strain depended on its proportion in the initial mix in a frequency-dependent manner that was consistent with a stable equilibrium. Thus, trade-offs between different fitness-related traits contribute to the co-existence of strains. Next, I studied interactions between members of different CSM species. Several species of CSMs were isolated from the same environment (Sathe et al., 2010); a question of interest was to see if amoebae of different species came together to form a chimaeric multicellular body. Five strains (two D. purpureum and three D. giganteum) were used in this study. Amoebae of D. giganteum and D. purpureum co-aggregated. However, there were factors that caused amoebae of the two species to sort out thereafter. The extent of segregation differed between strains, a characteristic that inter-species mixes share with intra-species mixes. In conclusion, the ability of cellular slime moulds to form multiclonal social groups in the wild suggests that one should look to factors in addition to close relatedness to understand the evolution of CSM social behaviour. The existence of fitness-related trade-offs between different traits indicates that individual-level selection can also contribute to the maintenance of chimaeric social groups.
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Détermination des coefficients de partage sang:air, urine:air et plasma:air de composés organiques volatils d’origine microbienne

Berkane, Wissam 12 1900 (has links)
Résumé: De nombreuses études ont établi que l’exposition aux moisissures intérieures peut être nuisible à la santé. Dans une récente étude, 21 composés organiques volatils microbiens (COVM) ont été sélectionnés comme biomarqueurs potentiels de l’exposition aux moisissures intérieures. L’objectif du projet était de déterminer les coefficients de partage (CP) sang:air, urine:air, plasma:air et eau:air pour ces composés, paramètres utilisés dans la prédiction de la toxicocinétique des xénobiotiques. Pour y parvenir, la méthode de flacons à l’équilibre a été utilisée. Les COVM (1.57-2.01 µg) injectés dans des flacons (20 ml) hermétiquement scellés contenant soit 0.5 ml de matrice (flacons test) ou simplement de l’air (flacons références) ont été incubés 60 min à 37⁰ C sous agitation continue. La quantification des COVM dans l’espace de tête des flacons (test et références) a été ensuite faite par chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC-MS/MS). Les CP de 19 COVM variaient entre 78 et 4721 pour sang:air, 14 et 3586 pour urine:air, 64 et 5604 pour plasma:air et 16 et 2210 pour eau:air. Les CP eau:air étaient étroitement liés aux CP urine:air pour 17 COVM (R2 = 0,97, pente =1,001) suggérant que la valeur de CP eau:air (lorsqu’inférieur à103) peut être un substitut au CP urine:air. L’étude des ratios sang:urine indique que six COVM seraient nettement plus concentrés dans le sang, matrice de choix pour ces composés. Les données générées par cette étude faciliteront le développement de modèles pharmacocinétiques de COVM et le paramétrage de leurs prélèvements en tant que biomarqueurs de l’exposition aux moisissures intérieures. / Abstract: Numerous studies have established that exposure to indoor molds can be harmful to health. In a recent study, 21 microbial volatile organic compounds (mVOCs) were selected as potential biomarkers of indoor mold exposure. The objective of the project was to determine the blood:air, urine:air, plasma:air, and water:air partition coefficients (PCs) for these compounds, parameters used in predicting the toxicokinetics of xenobiotics. To achieve this, the vial-equilibration method was used. mVOCs (1.57-2.01 µg) were injected into hermetically sealed vials (20 ml) containing either 0.5 ml of matrix (test vials) or simply air (reference vials) and were incubated for 60 min at 37 ⁰C under continuous agitation. Quantification of mVOCs in the headspace of the vials (test and reference) was then performed by gas chromatography mass spectrometry (GC-MS/MS). The PCs of 19 mVOCs ranged from 78 and 4721 for blood:air, 14 and 3586 for urine:air, 64 and 5604 for plasma:air, and 16 and 2210 for water:air. Water:air PCs were closely related to urine:air PCs for 17 mVOCs (R2 = 0.97, slope =1.001) suggesting that the water:air PC value (when less than 103) may be a surrogate for the urine:air PC. The blood:urine ratio study indicates that six mVOCs would be significantly more concentrated in blood, the matrix of choice for these compounds. The data generated from this study will facilitate the development of pharmacokinetic models of mVOCs and the parameterization of their sampling as biomarkers of indoor mold exposure.
89

Leland F. Prince's Earth Divers

Prince, Leland Fred 16 March 2010 (has links) (PDF)
My stoneware sculptures in my MFA final project were named Earth Divers because clay as a material is earth and clay is also symbolic of the Earth. The way that I physically dive into clay up to my elbows is a poetic performance. The sculptures were built in sections horizontally and then stacked vertically. I began the process by first making life size plaster molds of the human figure taken from live people. Earth Divers take their architectural structure specifically from the organic curves of the negative voids that are characteristic of the plaster figure molds. I built into these plaster molds a block or brick like section. I then removed the large block sections from the molds and stacked the sections one on top of the other combining the figurative and architectural structures with gothic influence. The sculptor, Stephen De Staebler, who works in a similar fashion, describes his work as, "... first laying the figure down and later standing it in a vertical position." The way of life that was lost with the manufacturing past of my family at Castone Brick is found in the use of industrial nostalgia by modeling I-beam shapes as part of the structure of the stacked sections. I also fired nuts, bolts, and washers of various sizes in the clay that build the surface of the human forms. The square nut seen in my work is no longer being manufactured and is symbolic of the passing of the industrial age in America. Finally, to build the surfaces of my sculptures I used slips, glazes, and a variety of clays on top of clay, and laid glass fragments on the horizontal surfaces to create a look of pooled water when my work was fired similar to what I have seen in the Lehman Caves in Baker, Nevada. "I believe there is a force in this world that lives beneath the surface, something primitive and wild that awakens when you need an extra push just to survive, like wild flowers that bloom after a fire turns the forest black. Most people are afraid of it and keep it buried deep inside themselves. But, there will always be a few people who have the courage to love what is untamed inside us." (Tim McGraw)
90

FUNGI AND `FUNGAL-LIKE’ ORGANISMS ASSOCIATED WITH ROOT SYSTEMS OF CUCURBITA MAXIMA AND THE SURROUNDING RHIZOSPHERE

Hulse, Jonathan Daniel 04 August 2016 (has links)
No description available.

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