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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.
11

Determinación de la resistencia a la compresión del concreto mediante el método de esclerometría / Determination of the resistance to compression of the concrete through the sclerometry method

Vélez Gallardo, Gustavo Antonio 23 August 2019 (has links)
Debido al crecimiento continuo que se tiene cada año del consumo del concreto como primer material de construcción, resulta de gran ayuda contar con distintos métodos no destructivos que nos permitan conocer, de una manera rápida y sencilla, la resistencia del concreto. Uno de los métodos no destructivos es el índice esclerométrico, que consiste en determinar nivel de compacidad de las partículas del concreto. Durante años se han hecho distintos estudios para correlacionar el índice esclerométrico y la resistencia del concreto, hallando altos niveles de relación; sin embargo, dichos estudios no toman en cuenta la edad del concreto ni el tipo de piedra que se utiliza en la mezcla, siendo parámetros que no resultan ajenos al ensayo de esclerometría. Por ello, la siguiente investigación propone el ensayo de dureza superficial (esclerometría) como un método confiable para la determinación de la resistencia del concreto analizando distintas muestras de acuerdo a su edad y tamaño máximo nominal. Estos factores serán analizados y serán almacenados en una base de datos en la que serán separados según su característica, generando distintos gráficos de regresión lineal para así aumentar el índice de confianza de correlación de Pearson. / The use of concrete as a primary construction material has seen steady increase year after year, which is why it is imperative to have at our disposal different non-destructive methods for quick and easy determination of its resistance. Once non-destructive method is the sclerometric index, which determines the level of compactness of the concrete particles. Various studies over years have found the sclerometric index to be highly correlated to concrete resistance. Nevertheless, these studies didn’t correct for factors such as the age and composition of the concrete mixture, both of which greatly influence sclerometry. They aim of this study was to determine whether superficial hardness testing (sclerometry) is an appropriate method for measuring concrete resistance, by analyzing samples of distinct age and maximum nominal size. These factors were analyzed and stored in a database which generated linear regression graphs, thereby improving the confidence interval for the Pearson correlation coefficient. / Tesis
12

Tradeoffs and social behaviour in the cellular slime moulds

Sathe, S. 13 April 2012 (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.
13

Molecular identification and quantification of the Penicillium roqueforti group /

Esberg Boysen, Marianne, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.
14

Biological control of grey mould in Swedish forest nurseries /

Capieau, Kristof, January 2004 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.
15

Antifungal activity of lactic acid bacteria /

Magnusson, Jesper, January 2003 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.
16

Fungal inhibitory lactic acid bacteria : characterization and application of Lactobacillus plantarum MiLAB 393 /

Ström, Katrin, January 2005 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.
17

Possibilities to improve silage conservation : effects of crop, ensiling technology and additives /

Knický, Martin, January 2005 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
18

Estudo aberto prospectivo de 30 pacientes com onicomicose por Scytalidium spp. tratados com terbinafina oral, ciclopiroxolamina esmalte e onicoabrasão / An open prospective study to compare the efficacy and safety of topical ciclopirox olamine as a monotherapy and in combination with oral terbinafine, associated to nail abrasion in the treatment of onychomycosis due to Sytalidium ssp

Ígor Brum Cursi 29 November 2010 (has links)
Onicomicose é um termo geral usado para definir infecção fúngica da unha. Seus agentes podem ser dermatófitos, leveduras ou fungos filamentosos não dermatófitos - FFNDs. Estes são comumente encontrados na natureza como saprófitas do solo e de restos vegetais e patógenos de plantas e têm sido considerados fungos patógenos primários de lesões cutâneas. Não existe até o momento terapêutica padrão para o tratamento de onicomicoses por Scytalidium spp., sendo escassos os dados na literatura pesquisada. Este trabalho tem como objetivo avaliar e comparar a resposta terapêutica a três abordagens diferentes de tratamento combinado para onicomicose por Scytalidium spp., todos associados à onicoabrasão. Foram selecionados 30 pacientes com diagnóstico de onicomicose provocada por Scytalidium spp., divididos em três grupos de dez, recebendo cada um os seguintes tratamentos, além da onicoabrasão: Grupo I: Terbinafina oral e esmalte de ciclopiroxolamina 8%, duas vezes por semana por 12 meses; Grupos II e III: Esmalte de ciclopiroxolamina 8%, duas e 5 vezes por semana, respectivamente, por 12 meses. Os parâmetros de avaliação da eficácia foram clínico e micológico ao término do tratamento e seis meses após. Foram utilizados os critérios de cura total, cura parcial, falha terapêutica aos 12 meses e recidiva/reinfecção no acompanhamento de seis meses. Vinte e cinto pacientes completaram o estudo. Não houve diferença estatística entre os grupos nos diversos parâmetros utilizados para avaliação da resposta terapêutica. A avaliação do resultado terapêutico mostra que ao final de 12 meses de tratamento apenas um paciente preencheu os critérios para cura total, e que 32% dos pacientes de todos os grupos apresentaram cura parcial. Todos os pacientes que completaram o estudo obtiveram melhora clínica, que se manteve no período de acompanhamento. A presença dos fungos na lâmina ungueal foi constante, mesmo com a melhora clínica. Embora não se possa afirmar qual a melhor forma de intervenção entre as três terapêuticas propostas devido ao pequeno número de pacientes do estudo, deduz-se, deste trabalho, que não houve vantagem na administração de terapia sistêmica concomitante. É possível considerar que a terapia tópica exclusiva, seja duas ou cinco vezes por semana, possa constituir opção mais adequada para o tratamento da onicomicose por Scytalidium spp. / Onychomycosis is a general term used to define a fungal infection of the nail. Its officials may be dermatophytes, yeasts and non-dermatophyte moulds. These are commonly found in nature as soil saprophytes and plant remains and plant pathogens. In recent years fungi have been considered primary pathogens of skin lesions. The main ones are Scopulariopsis and Scytalidium spp. There isnt by now a standard therapy for treatment of onychomycosis by Scytalidium spp., and there are few data in the literature. To evaluate and compare the therapeutic response to three different approaches of combined treatment of onychomycosis by Scytalidium spp., all associated with onicoabrasão. We selected 30 patients diagnosed with onychomycosis caused by Scytalidium spp, divided into three groups, each receiving the following treatments, besides receiving mechanical abrasion: Group I: oral terbinafine and ciclopirox 8% nail polish twice a week for 12 months; Groups II and III: Nail polish of ciclopirox 8% two and five times per week, respectively, for 12 months. Twenty-five patients completed the study. There was no statistical difference between groups in the various parameters used to evaluate therapeutic response. The evaluation of the therapeutic result shows that after 12 months of treatment only one patient met the criteria for cure, and that 32% of patients in all groups showed partial healing. All patients who completed the study achieved clinical improvement, which persisted during the follow-up period. The presence of fungi in the nail plate was constant, even with clinical improvement. Although one cannot say what the best form of intervention among the three therapeutic proposals due to the small number of patients studied, it appears in this study there was no advantage in the concomitant administration of systemic therapy. One may consider that topical therapy alone, or two or five times a week may be more suitable option for the treatment of onychomycosis caused by Scytalidium spp.
19

Influence de l'état physiologique sur la germination de spores appartenant aux genres Aspergillus et Penicillium / Influence of physiological state on germination of aspergilli and penicilli spores

Nanguy, Sidje Paule Marina 17 June 2011 (has links)
Les spores ou les conidies fongiques sont responsables de la dissémination des champignons filamenteux dans l'environnement (air, eau, sol,…). Ensuite les spores fongiques peuvent se déposer sur les équipements dans les ateliers de fabrication, sur les matières premières agricoles et sur les aliments. Au laboratoire, les spores sont obtenues en cultivant les champignons filamenteux en conditions optimales en termes de température, activité de l'eau, nutriments, de manière à obtenir le matériel biologique le plus rapidement possible. Or naturellement, lors de la sporulation, les champignons sont soumis à différents stress, notamment hydrique, ce qui entraîne des différences notables dans l'état physiologique de la spore. Ainsi notre objectif durant cette thèse est d’évaluer l’état physiologique des spores lorsqu’elles sont soumises à certaines conditions. Une première partie de la thèse vise à établir un nouveau modèle pour une meilleure détermination du temps de germination. L’étape suivante présente l’évaluation de l’influence du stress hydrique de la sporogénèse à la germination des spores. Les deux dernières parties présentent enfin l’évaluation des conditions de stockage sur la germination des spores. L’état physiologique est un facteur clé dans le processus de germination, il serait opportun de l’intégrer dans les modèles prédictifs de la germination. / Fungal spores or conidia are responsible for filamentous fungi spread in environment (air, water, soil…). Then, they can be found on several environments including foods. In laboratory spores are obtained under favorable conditions. However, these conditions are not real, spores are subject to various stress including water stress after their formation. These conditions can make some interactions with their physiological state. Thus, our aim consists in evaluating spores physiological state after their exposition to various conditions of storage. First part of this thesis is about definition of a new model of germination for improving germination time determination. Next step concerns evaluation of water stress during spore’s germination process. The last two parts are finally dedicated to evaluation of storage condtions on spore’s germination time. Physiological state is a key factor in the germination process. It would be appropriate to include this factor in predictive models.
20

Mikološki i mikotoksikološki aspekti pojave plesni u začinima / MycologicaI and Mycotoxicological Aspects of Mould Incidence in Spices

Dimić Gordana 28 February 2000 (has links)
<p>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR)</p><p>Ispitano je prisustvo plesni u začinskim sme&scaron;ama (za proizvodnju mortadele, mesnog nareska, srpske Ijute kobasice, alpske i tirolske salame, vir&scaron;le i &scaron;unkarice), crnom biberu u zrnu i mlevenoj začinskoj paprici. Intenzitet kontaminacije bio je najveći u začinskim sme&scaron;ama (46,13%), zatim crnom biberu (28,95%) i začinskoj paprici (24,92%).<br />Uočena je dominacija grupe kserofilnih plesni iz rodova Aspergillus, Emericella, Eurotium, Paecilomyces, Penicillium i Xeromyces. Konstatovano je da su u začinskim sme&scaron;ama i crnom biberu najbrojniji bili predstavnici rodova Aspergillus i Penicillium, ali su po zastupljenosti u uzorcima (100%) dominirale plesni roda Eurotium {E. herbariorum). U uzorcima začinske paprike najče&scaron;će su detektovane plesni roda Rhizopus (R. stolonifer) (87,5%).<br />Od ukupno 45 vrsta identifikovanih tokom mikolo&scaron;kih ispitivanja začina, 55,5% je bilo potencijalno toksigenih. Prisustvo aflatoksina B1 nije konstatovano ni ujednom od začina, ohratoksin A je pronađen kod dva uzorka crnog bibera (u tragovima; 32,00 &mu;g/kg), a zearalenon kod tri uzorka crnog bibera (192,00 do 288,00 &mu;g/kg).<br />Sposobnost sinteze ohratoksina A utvrđena je kod 4 od 5 testiranih sojeva Aspergillus ochraceus (20,00 do 340,00 &mu;g /1). Većina sojeva A. versicolor i 50% E. herbariorum sintetisali su sterigmatocistin u značajnim količinama (100,00 do 1600,00 &mu;g /1, odnosno l60,00 do 400,00 &mu;g /l).<br />A. versicolor se pokazao prilično tolerantnim na uzlaganje visokim temperaturama, preživev&scaron;i toplotni tretman na 800C (5 i 10 min), ali je naru&scaron;ena fiziolo&scaron;ka aktivnost rezultovala smanjenjem proizvodnje sterigmatocistina.</p><p>Koncentracijom kalijum sorbata od 0,5% u potpunosti je inhibiran rast A. versicolor na čvrstoj hranljivoj podlozi, ali ne i u tečnoj; proizvodnja sterigmatocistina registrovana je samo pri nižim koncentracijama (0,05 i 0,1%).</p> / <p>Abstract was processed by technology for Optical character recognition (OCR)</p><p>The presence of moulds in spice mixtures (for production of mortadella, luncheon meat, &quot;serbian&quot; hot sausage, &quot;alpine&quot; and &quot;tirol&quot; salami, Frankfurter and ham sausage) was investigated. The highest intensity of contamination was in spice mixtures (46,13%), then in black pepper (28,95 %) and in ground red pepper (24,92%).<br />The group of xerophyllic moulds of genera Aspergillus, Emericella, Eurotiiim, Paecilomvces, Penicillium and Xeromyces was dominant. It was found out that the representatives of genera Aspergillus and Penicillium were the most numerous, but considering the incidence in samples (100%) the moulds of genus Eurotium (E. herbariourum) were dominant. In samples of ground red pepper the moulds of the genus Rhizopus (R. stolonifer) (87,5%) were the most frequently detected. Among 45 species identified during mycological investigation of spices, 55,5% were possibly toxicogenic. The presence of aflatoxin B1 was not observed in any of spices tested, ochratoxin A was found in two samples of black pepper (from traces to 32,00 &mu;g/kg), and zaeralenone in three samples of black pepper (192,00 to 288,00 &mu;g/kg).<br />The ability for synthesis of ochratoxin A was observed in 4 of 5 tested strains of Aspergillus ochraceus (20,00 to 340,00 &mu;g/1). The majority of A. versicolor strains and 50% of E. herbariorum synthesized sterigmatocystin in significant quantities (100,00 up to 1600,00 &mu;g/1, and l60,00 up to 400,00 &mu;g/l, respectively).</p><p>A. versicolor showed to be rather tolerant to exposure to high temperatures by surviving the heat treatment at 800C (5 and 10 min), but the disturbed physiological activity resulted in reduced production of sterigmatocystin.<br />By concentration of potassium sorbate of 0,5% the growth of A. versicolor on solid medium was totally inhibited, but not on liquid medium; the production of sterigmatocystin was registered only at lower concentrations (0,05 and 0,1%).</p>

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