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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.
31

Didaktik i fritidshem : en diskursteoretisk studie av hur begreppet didaktik framställs

Söderholm, Jonas January 2021 (has links)
Lärare, pedagoger, författare, forskare och myndigheter – i stort sett alla som har en yrkesmässig koppling till fritidshem – har olika tankar, idéer och tal om som formar och omformar diskurser gällande fritidshemmets didaktik. Fritidshemmet har numera ett skolnära uppdrag och ska komplettera skolan. Fritidshemmets pedagogiska verksamhet är dock något annat än skolans vilket även motiverar behovet av denna studie. En pedagogisk verksamhet som bidrar till att stimulera elevers lärande och utveckling av förmågor genom att ha fokus på deras intressen, behov, nyfikenhet och erfarenhet. Fritidshemmets unika verksamhet kan möjliggöra en större självständighet i såväl val av innehåll samt med andra medel och metoder än skolans generellt mer inrutade verksamhet. Syftet med studien är att ur ett diskursteoretiskt perspektiv undersöka hur diskursen gällande didaktik i fritidshem framställs i tolv lärosätens självvärderingar och Universitetskanslersämbetets tolv yttrande vid bedömning av kvaliteten på grundlärarutbildningar med inriktning mot arbete i fritidshem. Utifrån ett diskursteoretiskt perspektiv och en diskursanalytisk ansats studeras de diskursiva bilder som de olika institutionerna och myndigheten tilldelar begreppet didaktik i relation till undervisning i fritidshemmet och studenters blivande yrkesroll.Resultatet visar att det finns hegemoniska intentioner som riktas mot att förtydliga såväl didaktiken som den ämnesspecifika didaktiken i relation till fritidshemmets pedagogik. Examensmålet som uttalar att studenter specifikt ska visa förmåga att tillämpa sådan didaktik och ämnesdidaktik inklusive metodik som krävs för undervisning och lärande inom det fritidspedagogiska området och inom det eller de ämnen som utbildningen avser och för yrkesutövningen i övrigt blir en hegemonisk ekvivalenskedja i sig själv. Resultatet visar att begreppet didaktik beskrivs ur flera olika aspekter men vad som är fritidshemmets didaktik eller ämnesdidaktik redogörs inte mer än i ett fåtal antagonistiska exempel. Utifrån de analyserade texterna ger resultat ett den hegemoniska intentionen i att precisera didaktiken inte innebär att definiera begreppet utan snarare att beskriva på vilka sätt studenterna tillägnar sig denna didaktiska kompetens. / Teachers, educators, authors, researchers and authorities - virtually everyone who has a professional connection to School-Age Educare - have different thoughts, ideas and speeches that shape and reshape discourses regarding the didactics of the School-Age Educare. The School-Age Educare now has a school-based mission and will complement the school. The pedagogical activities are, however, something other than the school's needs, which also justifies the need for this study. An educational activity that helps to stimulate students' learning and development of abilities by focusing on their interests, needs, curiosity and experience. I believe that the School Age-Educare´s unique activities thus give children greater independence in both the choice of content and with other means and methods than the school's generally more structured activities do. The purpose of this study is to, from a discourse theoretical perspective, examine how the discourse regarding didactics in School-Age Educare is presented in twelve higher education institutions' self-evaluations and the University Chancellor's Office's twelve opinions when assessing the quality of primary teacher education with a focus on work in School-Age Educare. With a discourse theoretical approach, the discursive image that the various institutions and the authority give the concept of didactics in relation to teaching in School-Age Educare and students' future professional role is studied.The results show that there are hegemonic intentions aimed to clarify both the didactics and the subject-specific didactics in relation to the School-Age Educare pedagogy. The degree objective, which states that students must specifically demonstrate the ability to apply such didactics and subject didactics, including methodology required for teaching and learning in the School-Age Educare area and in the subject or subjects to which the education relates and for professional practice in general, becomes in itself a hegemonic chain of equivalence. The results show that the concept of didactics is described from several different aspects, but what the didactics of the School-Age Educare or subject didactics are, is not reported more than in a few antagonistic examples. The hegemonic intention of the University Chancellor's Office as an authority in specifying didactics does not mean defining the concept but rather describing the ways in which students acquire this didactic competence.
32

Blues & det politiska : Identitet, konflikt och feministiskt motstånd inom Stockholms informella bluesmusiknätverk

Ramberg, Anna Kajsa January 2022 (has links)
The title of this study is Blues & the Political: Identity, Conflict & Feminist Resistance in the Stockholm Informal Blues Music Network. The aim of this study is to examine struggles over power, the construction of identity and the role of the meanings of blues within the Stockholm blues music network from a feminist and intersectionalist perspective. The overarching research question is how the informal network could be seen as political in the sense of a societal struggle over power. Three major power struggles were identified in the interviews with white female blues musicians.   The first struggle takes place between female musicians and older men where conflicts about representation, recognition and authenticity are articulated. A major conflict is about how the blues should be played. Most of the interviewed musicians see themselves as playing modern blues, whereas the older men mostly are portrayed as “organizers”, “blues police”, or “puritans” with a conservative view of blues, and thereby discursively excluding the blues women from the genre, causing negative affect, mostly expressed by cursing. Especially younger blues women are contesting the concept of blues as a twelve-bar structure. Paradoxically, they all partly see it as a very significant element of blues, which indicates a masculine hegemony influencing their minds. Feminist resistance is expressed through irony, anger, debate, lyrics, and performance. Two out of seven musicians do not express a feminist ideology and several express fatigue and resignation. One of them, however, said that taking to the stage is almost enough as a form of resistance. In this way all musicians are ‘claiming space’.   The second power struggle takes place between younger and older musicians, where the younger ones can be seen as part of reproducing a hegemonic masculinity rendering the older blues women invisible. The third struggle concerns cultural appropriation. Black female musicians are said to be not good enough, not welcome because of critique of cultural appropriation or excluded because of their association with jazz, as the white musicians construct jazz as opposed to blues. Although the younger musicians partly express feelings of understanding towards their opponents and there is consensus about the importance of representation in general, the older blues women are more inclined to see accusations of appropriation as racism.
33

Preparedness for mass-casualty attacks on public transportation

Holgersson, Annelie January 2016 (has links)
Background: Public transportation constitutes a vulnerable sector in modern day society with a high probability of generating mass casualties if attacked. By preparing for mass-casualty attacks (MCAs), response can become more effective and public transportation can become a less rewarding target. However, preparedness for attacks, much like response, implies resource constraints, and this dissertation pinpoints some major dilemmas that inhibit achieving preparedness for MCAs on public transportation in Sweden. Aim: The aim of this dissertation was to investigate preparedness for mass-casualty attacks on public transportation. This allowed for identification of major challenges for preparedness and response with a particular focus on the Swedish context. Methods: Study I included 477 MCAs identified through searches of the Global Terrorism Database, journals, newspapers and websites, which were examined with descriptive statistics. Study II thematically analyzed 105 articles attained by systematic searches of the PubMed and Scopus databases. Study III and IV statistically analyzed data from 864 responses to a purposive-designed questionnaire, from operational personnel of the Swedish emergency organizations. Study V entailed validation of a finite element (FE) simulation model of a bombing in a train carriage compared to the bombings in Madrid 2004. Results: International trends of MCAs (≥ 10 fatally injured and/or ≥ 100 non-fatally injured) on public transportation, during the years 1970-2009 (I) showed that the average number of injured increased considerably, despite a quite stable incidence rate since the 1980s. High numbers of injured people were connected to attacks on terminal buildings, multiple targets and complex tactical approaches. Few MCAs occurred in Europe, but the average number of fatalities per incident and injured per incident were the second highest among regions. The literature study (II) of previous on-scene management showed that commonly encountered challenges during unintentional incidents were added to during MCAs, implying specific issues for safety, assessment, triage and treatment, which require collaborative planning and specific training. The study regarding the Swedish emergency organizations’ perceptions of terrorist attacks (III) showed significant differences on perceptions of event likelihood, willingness to respond, estimated management capability and level of confidence in knowledge of tasks to be performed on scene. The police respondents stood out; e.g., fewer police personnel had high estimates of their organizations’ management capability and knowledge of tasks on-scene compared to the other organizations. The study of factors that influence responders’ perceptions of preparedness for terrorism (IV) showed that these were influenced by the responders’ sex, work experience, organizational affiliation, various training arrangements and access to personal protective equipment (PPE). Investing in amenable factors, such as terrorism-related management training and provision of PPE, could improve responders’ perceptions of preparedness for terrorism. A finite-element (FE) model of an explosion in a train carriage (V) was developed and showed that FE modeling techniques could effectively model damage and injuries for explosions with applicability for preparedness and injury mitigation efforts, but, also, there was room for improvement of the model in terms of injuries. Conclusion: Achieving preparedness for MCAs on public transportation is a multiple choice balancing act between ostensible dilemmas regarding investments, disaster plans, training, response strategies, collaboration and inventions. / Bakgrund: Kollektivtrafik utgör en sårbar sektor i dagens samhälle, med hög sannolikhet att generera en situation med många drabbade vid attentat. Genom att förbereda för masskadeattentat (MCA) kan hanteringen bli effektivare och kollektivtrafiken utgöra ett mindre givande mål. Beredskap för attentat, liksom själva hanteringen, innefattar dock resursbegränsningar och denna avhandling belyser somliga avgörande utmaningar som hämmar utvecklandet av beredskap för MCA mot kollektivtrafiken i Sverige.   Syfte: Syftet med avhandlingen var att undersöka beredskapen för masskadeattentat mot kollektivtrafik. Detta möjliggjorde identifiering av stora utmaningar för beredskap och insatser, med särskilt fokus på den svenska kontexten.   Metoder: Studie I innefattade 477 MCA som identifierades genom sökningar i Global Terrorism Database, vetenskapliga tidskrifter, tidningar och webbsidor, som sedan undersöktes med deskriptiv statistik. I Studie II genomfördes en tematisk analys av 105 artiklar, funna genom systematiska sökningar i databaserna PubMed och Scopus. I Studie III och IV genomfördes statistisk analys av data från 864 respondenter till en ändamålsenligt utformad enkät, utskickad till operativ personal inom blåljusorganisationerna. Studie V innebar validering av en finita element (FE)-modell av en explosion i en tågvagn genom jämförelse med bombningarna i Madrid 2004.   Resultat: I den internationella utvecklingen av MCA (≥ 10 dödsfall eller ≥ 100 icke-dödligt skadade) mot kollektivtrafik, under åren 1970-2009 (I) visade det sig att det genomsnittliga antalet skadade ökade kraftigt, trots en tämligen stabil incidens av antalet händelser sedan 1980-talet. Skadadeutfallet var ofta stort vid angrepp på terminalbyggnader, multipla mål och användning av komplexa taktiska metoder. Få MCA inträffade i Europa, men det genomsnittliga antalet dödsfall per fall och skadade per fall var den näst högsta bland regioner. Litteraturstudien (II) av skadeplatshantering vid tidigare attentat visade att vanligt förekommande utmaningar under oavsiktliga masskadehändelser utökades under MCA med särskilda svårigheter kring säkerhet, bedömning, triage och behandling, vilket i sin tur kräver gemensam planering och särskild utbildning. Studien om de svenska blåljusorganisationernas uppfattningar om terroristattacker (III) visade signifikanta skillnader på uppfattningar om sannolikhet av olika händelser, viljan att respondera, beräknad hanteringskapacitet och förlitan till kunskap om uppgifter som ska utföras på skadeplats. Polisernas svar utmärkte sig; t.ex. hade färre inom polisen höga uppskattningar av sin organisations hanteringskapacitet och sin egen kunskap om uppgifter på plats, jämfört med de andra organisationerna. Studien av vilka faktorer som påverkade respondenternas uppfattning om beredskap för terrorism (IV) visade att uppfattningar påverkades av deras kön, arbetslivserfarenhet, organisationstillhörighet, olika former av utbildning och tillgång till personlig skyddsutrustning. Investeringar i åtgärder såsom terrorism-relaterad träning och personlig skyddsutrustning skulle kunna förbättra uppfattning om beredskap för terrorism inom blåljusorganisationerna. En FE modell av en explosion i en tågvagn (V) utvecklades och visade att FE metoden skulle kunna modellera materiella skador och personskador av explosioner, med tillämpning för beredskap och skadelindrande åtgärder, men visade också att det fanns utrymme för förbättring av modellen avseende personskador.   Slutsats: Förverkligandet av beredskap för masskadeattentat mot kollektivtrafik utgör en balansgång i beslutstagande mellan vad som förefaller vara dilemman om investeringar, krisplaner, utbildning, responsstrategier, samverkan och innovationer. / Preparedness for mass-casualty attacks on public transportation
34

The architecture of antagonistic networks

Nuwagaba, Savannah 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Designing a mechanistic model that can give rise to realistic architecture of ecological networks is central to the understanding of how species assemble and function in ecosystems. As species are constantly adjusting their diets in an antagonistic network, we here incorporate this adaptive behaviour of diet choice into a bipartite network model, with the effect of antagonistic interactions between species depicted by Holling’s type II functional response. Predictions of this model fit extremely well with the observed levels of nestedness, modularity and node-degree distributions for 61 real host-parasitoid and plant-herbivore networks. We further examined two specific scenarios of our model (species with identical [neutral] demographic parameters and interactions with identical [neutral] benefit in the network) and found that the demography-neutral scenario overestimated observed modularity, whilst the benefit-neutral scenario over-estimate observed nestedness. Relationships between nestedness, modularity and connectance were found strong. Moreover, in contrast to the common belief of the high modularity in antagonistic networks, most real networks (> 80%) are significantly nested, whilst nearly 40% of the real networks are surprisingly less compartmentalized than random networks generated from null models. Regardless of the controversy on whether antagonistic networks are nested or compartmentalized, the proposed model captured the essence of the dynamic nature of structural emergence in antagonistic networks. Due to its predictive power, this model was further used to investigate robustness in antagonistic networks. Predictions showed that the robustness of a network is determined by many factors, such as connectance, resource degree distribution, resource-consumer ratio, diversity, nestedness and compartmentalisation. Surprisingly, the manner of network response to species loss was independent of the sequence followed while removing species from a network. Variations were only noticed in the intensity of the effect resulting from the removals. In addition, we also showed that species extinction procedures which ignore the interaction switch underestimate the effect of any loss of species in these networks. We must therefore value our knowledge of possible adaptive processes in the ecosystem as they may be important for resolving the diversity-stability debate. / AFRIKAANSE OPSOMMING: Die ontwerp van ’n meganistiese model wat aanleiding kan gee tot realistiese argitektuur van ekologiese netwerke is sentraal tot die begrip van hoe spesies bymekaar kom en funksioneer in ekosisteme. Soos spesies voortdurend hul dieet aanpas in ’n antagonistiese netwerk, het ons hierdie aanpasbare gedrag van dieet keuse in ’n bipartiet netwerk model ingewerk, met die effek van antagonistiese interaksies tussen spesies wat uitgebeeld word deur Holling se tipe II funksionele reaksie. Voorspellings van hierdie model pas baie goed met die waargenome vlakke van nestedness, modulariteit en node-graad uitkerings vir 61 ware gasheer-parasiet en plant-herbivoor netwerke. Verder het ons twee spesifieke gevalle van ons model (spesies met identiese [neutrale] demografiese parameters en interaksies met identiese [neutrale] voordeel in die netwerk) ondersoek en gevind dat die demografie-neutrale geval waargenome modulariteit oorskat, terwyl die voordeelneutraal geval waargenome nestedness oorskat. Verhoudings tussen nestedness, modulariteit en konnektiwiteit is sterk bevind. Verder, in teenstelling met die algemene verwagting van hoe modulariteit in antagonistiese netwerke, is oorhoofse werklike netwerke (> 80%) aansienlik geneste, terwyl byna 40% van die werklike netwerke is verbasend minder gekompartimenteerd as ewekansige netwerke gegenereer uit null modelle. Ongeag van die omstredenheid oor of antagonistiese netwerke geneste of gekompartimenteerd is, die voorgestelde model vang die essensie van die dinamiese aard van die strukturele opkoms in antagonistiese netwerke. As gevolg van sy voorspellende krag, is hierdie model verder gebruik om robuustheid te ondersoek in antagonistiese netwerke. Voorspellings het getoon dat die robuustheid van ’n netwerk word bepaal deur verskeie faktore, soos konnektiwiteit, hulpbron-graad verspreiding, hulpbron-verbruiker verhouding, diversiteit, nestedness en kompartementasie. Verrassend, die wyse van die netwerk reaksie op die verlies van spesies was onafhanklik van die reeks wat gevolg het toe die spesies verwyder is uit ’n netwerk. Variasies is slegs opgemerk in die intensiteit van die effek van die verskuiwings. Benewens, ons het ook aangetoon dat die prosedures van spesies se uitsterwing wat die interaksie skakelaar geignoreer het, onderskat die effek van ’n verlies van spesies in hierdie netwerke. Ons moet dus die waarde van ons kennis van die moontlike aanpassing prosesse in die ekosisteem in agneem, aangesien dit belangrik kan wees vir die oplossing van die diversiteit-stabiliteit debat.
35

Process Improvements to Fed-batch Fermentation of Rhodococcus rhodochrous DAP 96253 for the Production of a Practical Fungal Antagonistic Catalyst

Barlament, Courtney 12 August 2016 (has links)
Recent evaluations have demonstrated the ability of the bacteria Rhodococcus rhodochrous DAP 96253 to inhibit the growth of molds associated with plant and animal diseases as well as post-harvest loss of fruits, vegetables and grains. Pre-pilot-scale fermentations (20-30L) of Rhodococcus rhodochrous DAP 96253 were employed as a research tool with the goal of producing a practical biological agent for field-scale application for the management of white-nose syndrome (WNS) in bats and post-harvest fungal losses in several fruit varieties. Several key parameters within the bioreactor were evaluated for the potential to increase production efficiency as well as activity of the biocatalyst. These parameters included elapsed fermentation time, dissolved Oxygen, and carbohydrate concentration of which increased carbohydrate concentration at the time of harvest was shown to have a negative impact on the catalyst activity. In addition, process improvements including utilization of a liquid inoculum, an autoinduction feed strategy, and increased glucose concentration in the feed medium increased fermentation yields to 100-150g/L, while the biocatalyst efficiency was increased from previous work. To increase production efficiency, a multi-bioreactor scheme was developed that used a seed bioreactor and subsequent production tank, which doubled run yields per production cycle. Amidase, cyanidase, urease, and alkene-monoxygenase activity were monitored throughout the study as potential indicators for the multi-faceted mechanism of fungal antagonism. Of these amidase, cyanidase, and urease were demonstrated to be more elevated in cells that showed antifungal activity than those that did not. This study represents the first example of a reproducible pre-pilot plant-scale biomanufacturing process for a contact-independent biological control agent for established and emerging fungal pathogens of plants and animals, and facilitates large-scale production for broad application.
36

L'Afrique dans l'antagonisme Est-Ouest de 1970 à 1991 / Africa in the East-West antagonism 1970-end 1991

Sess, Gnagne Antoine 14 December 2009 (has links)
Marginalisée et cantonnée jusqu’alors à la périphérie de la guerre froide, l’Afrique devient dans les années 1970, l’enjeu de rivalités entre les grandes puissances. Et pour cause. Les nombreuses faiblesses et l’intérêt stratégique du continent ainsi que les changements qui affectent le monde dans les années 1970 offrent aux deux grands l’occasion de s’y affronter. L’initiative de cet affrontement revient à l’Urss et à ses alliés qui, profitant de l’effacement relatif des Occidentaux, s’introduisent successivement en Afrique australe et dans la Corne de l’Afrique faisant de l’Afrique Subsaharienne un terrain de l’expansionnisme soviétique. Ces rivalités influencent considérablement la vie politique, économique et sociale du continent. De sorte que la fin de ce conflit entraîne un bouleversement du paysage politico-stratégique de la période de guerre froide et la perte de la valeur stratégique du continent. / Previously marginalized and relegated to the periphery of the cold war, Africa became in the 1970 s, the challenge of competition between major powers. And for good reason. The many weaknesses and the strategic interest of the continent and the changes that affect the world in the 1970 s offer two major an opportunity to confront each other. The initiative of this confrontation is for the USSR and allies who, taking advantage of erasure of western, introduce successively in the southern Africa and Horn of Africa and transform sub-saharan Africa in an area of soviet expansionism. This competition has considerable influence on political, economic and social point of the continent. So that the end of this conflict leads to a disruption.
37

Uso de Metarhizium spp. na produção de mudas pré-brotadas de cana-de-açúcar e seus efeitos na planta, em pragas e doenças / Use of Metarhizium spp. in the production of pre-sprouted seedlings of sugarcane and its effects on plant, pests and diseases

Siqueira, Ana Carolina Oliveira 28 January 2016 (has links)
Os fungos do gênero Metarhizium são entomopatogênicos e ainda apresentam relações endofíticas e podem viver saprofiticamente no solo. A associação desses microrganismos com insetos é bem conhecida, mas as interações diretas com as plantas ainda são incipientes. Objetivou-se com este estudo, determinar a capacidade de colonização endofítica em raízes de cana-de-açúcar (Saccharum spp.) de M. robertsii, M. anisopliae e três linhagens brasileiras recém-descobertas, bem como revelar o potencial destes fungos como antagonistas a dois fungos fitopatogênicos responsáveis pela podridão-vermelha (Fusarium moniliforme e Colletotrichum falcatum) e no controle de duas importantes pragas, a broca da cana-de-açúcar, Diatraea saccharalis e o nematóide-das-galhas, Meloidogyne javanica. Foram utilizados 24 isolados de Metarhizium spp. nos experimentos de promoção de crescimento de plantas após a inoculação em gemas de cana-de-açúcar em condições de casa-de-vegetação e campo. O efeito da inoculação do fungo em mudas de cana-de-açúcar foi investigado quanto a mortalidade e redução no desenvolvimento de D. saccharalis e redução nas populações de M. javanica. Experimentos de inibição in vitro em cultivo pareado foram conduzidos com os fungos F. moniliforme e C. falcatum e Trichoderma harzianum. Além disto, foram realizados testes qualitativos \"in vitro\" para avaliar a capacidade desses fungos em produzir β-1,3-Glucanase e Sideróforos. A inoculação de Metarhizium de todas as espécies testadas promoveu o crescimento de parte aérea, peso úmido e seco de raízes em relação ao controle (água). Enquanto o tratamento de gemas rotineiramente usado na usina onde se realizou a produção de mudas pré-brotadas com aplicação do fungicida Comet® + o fertilizante Biozyme TF resultou em pegamento de 32% e 59,6%, apenas com o uso de isolados de Metarhizium spp. estes valores foram de até 50% e 86,4%, nos dois experimentos em campo, respectivamente. As mortalidades observadas em lagartas de D. saccharalis que se alimentaram das plantas inoculadas com isolados de Metarhizium spp. atingiram valores de até 80%, sendo a mortalidade confirmada pela esporulação do fungo de até 55%. As lagartas sobreviventes apresentaram menor peso do que aquelas do controle não tratado. A inoculação de Metarhizium spp. em mudas de cana-de-açúcar conferiu proteção a M. javanica, resultando em uma densidade de massa de ovos por grama de raiz nas mudas inoculadas com o fungo até 59,8% menor no primeiro experimento e 64,1% menor no segundo em relação as mudas sem inoculação. Os ensaios de antagonismo mostraram que, todos os isolados de Metarhizium spp. apresentaram alguma forma de inibição tanto para F. moniliforme como para C. falcatum. Dos 24 isolados testados, 20,8% produziram a enzima hidrolítica, β-1,3-glucanase, o que pode estar associado a capacidade de inibição dos fungos fitopatogênicos. Constatou-se que 8 (33,3%) dos isolados produziram sideróforos e sugere que esses fungos apresentam mecanismos de disponibilização do ferro. O conhecimento gerado com este estudo poderá subsidiar novas estratégias de utilização de Metarhizium spp. em campo na produção de MPB de cana-de-açúcar. / The fungi of the genus Metarhizium are entomopathogenic and still have endophytic relations and can live in the soil as saprophytes. The association of these microorganisms with insects is well known, but the direct interactions with the plants are still incipient. The objective of this study was to determine the endophytic colonization capacity in sugarcane roots (Saccharum spp.) of M. robertsii, M. anisopliae and three new Brazilian lineages and to reveal the potential of these fungi as antagonists to two pathogenic fungi responsible for red rot (Fusarium moniliforme and Colletotrichum falcatum) and in control of two major pests, the sugarcane borer, Diatraea saccharalis and nematode, Meloidogyne javanica. Twenty four isolates of Metarhizium spp. were used in plant growth promoting experiments after inoculation in sugarcane plantings in greenhouse and field. The effect of fungal inoculation of sugarcane seedlings was investigated on mortality and development of D. saccharalis, and populations reduction of M. javanica. Inhibition experiments were conducted by in vitro cocultivation with the fungi F. moniliforme and C. falcatum and Trichoderma harzianum. Moreover, qualitative tests were carried out \"in vitro\" for evaluating the capacity of fungi to produce beta-1,3-glucanase and Siderophores. The inoculation of Metarhizium of all species tested promoted the shoot growth, wet and dry root weight compared to control (water). While chemical treatment of seedlings routinely used in sugarcane mills with fungicide application COMET® and fertilizer (Biozyme TF) resulted in 32% and 59.6% efficacy, only with the use of Metarhizium spp. these values were 50% and 86.4%, in both experiments in the field, respectively. Mortalities observed in caterpillars of D. saccharalis that fed the plants inoculated with isolates of Metarhizium spp. reached values of 80%, with the rate of confirmed mortality up to 55%. Caterpillars survivors had lower weight than the untreated control. The inoculation of Metarhizium spp. in sugarcane seedlings conferred protection to M. javanica, resulting in density of egg mass per gram of root in seedlings inoculated with the fungus 59.8% lower in the first experiment and 64.1% lower in the second compared to the seedlings without inoculation. Antagonism assays showed that all isolates of Metarhizium spp. had somehow inhibiting both F. moniliforme and C. falcatum. Among the 24 isolates tested, 20.8% produced the hydrolytic enzyme beta-1,3-glucanase, which may be associated with the ability of inhibiting the phytopathogenic fungi. It was found that eight (33.3%) isolates produced siderophores and suggests that these fungi have iron delivery mechanisms. The knowledge generated by this study may help new strategies for use of Metarhizium spp. on field to produces sugarcane seedlings.
38

Curvas de dose resposta e isobologramas como forma de descrever a associação dos inibidores da ALS (sulfometuron-methyl e chlorimuron-ethyl) em Digitaria insularis (L.) Fedde / Dose response curves and isobolograms as way of describing the association of the ALS inhibitors (sulfometuron-methyl e clorimuron-ethyl) in Digitaria insularis (L.) Fedde

Paris Junior, Marco Antonio 15 June 2018 (has links)
O interesse em efeitos sinérgicos ou antagônicos através de experiências com associações cresceu imensamente nas últimas décadas. Com o objetivo de estudar a associação de dois herbicidas inibidores da ALS (sulfometuron-methyl e chlorimuron-ethyl) em Digitaria insularis, empregou-se dos métodos estatísticos fornecidos por meio das curvas dose-resposta e isobologramas. O conceito de curvas dose-resposta tem sido amplamente utilizado para avaliar os resultados das experiências com herbicidas. No entanto, a abordagem estatística em torno das curvas deve ser cuidadosa; cosiderar as curvas dose-resposta semelhantes quando elas não são pode influenciar muito na comparação entre as moléculas e afetar o cálculo da potência relativa. A potência relativa ajuda a entender qual é a relação de potência entre as moléculas, esse conhecimento é fundamental para os estudos com os herbicidas em associação. Sabendo-se disso foram conduzidos experimentos do tipo dose-resposta em dois tipos de substratos utilizando Digitaria insularis como planta daninha indicadora. Os experimentos foram conduzidos em casa de vegetação do Centro de Pesquisa e Desenvolvimento da DuPont em Paulínia (SP). Para cada molécula foram aplicadas, em pré-emergência, oito doses com quatro repetições cada e quatro plantas testemunha nos diferentes substratos. O substrato A é somente substrato comercial (marca Tropstrato HT®) puro; E o substrato B é uma mistura de solo arenoso, peneirado e livre de contaminação mais substrato comercial na proporção 3:1 v/v. Neste caso ficou evidente a maior capacidade do sulfometuronmethyl em reduzir a biomassa da espécie, as curvas dose-resposta foram descritas pelo modelo log-logístico com os valores de ED50 e as declividades de cada curva variando livremente, pois as hipóteses testadas nos diferentes substratos de curvas paralelas foram rejeitadas. O valor calculado da potência relativa para o nível de resposta de 50% entre os herbicidas CLASSIC® (chlorimuron-ethyl) e CURAVIAL® (sulfometuron-methyl) nas condições desse estudo foi de 8,596 e 44,047 nos Substrato A e B respectivamente. A partir dessa informação foram utilizadas as mesmas condições do experimento anterior para o experimento com as isoboles dos herbicidas em associação, cinco curvas dose-resposta, foram propostas, duas curvas para os produtos isolados e três curvas para as associações em diferentes proporções [(25% : 75%); (50% : 50%); (75% : 25%)] chlorimuron-ethyl / sulfometuron-methyl, totalizando 144 parcelas. Vários modelos isoboles foram testados, o modelo de Concentração Aditiva foi significativamente descartado, mas foi levado em consideração para testar teoricamente o grau de sinergia ou antagonismo que modelos mais complexos podiam fornecer. O modelo de isobole proposto por Hewlett e Plackett (1959) teve ajuste significativo e parâmetro de interação menor que um (λ=0,33). O modelo que mais se ajustou aos dados foi o proposto por Vølund e os resultados também mostraram que nessas condições a associação de sulfometuron-methyl com chlorimuron-ethyl foi antagônica; as isoboles são potentes ferramentas para capturar e descrever associações de herbicidas. Entretanto a literatura mostra que associar duas moléculas e testar em um sistema biológico complexo sofrendo variações das diferentes condições ambientais possíveis pode gerar respostas variáveis, portanto esses resultados devem ser repetidos em outras condições para validar as conclusões ou então serem executados em condições controladas de laboratório e usar organismos vivos de menor complexidade como bioindicador. / The interest in synergistic or antagonistic effects through experiences with associations has immensely grown in recent decades. In order to study the association of two ALS inhibitor herbicides (sulfometuron-methyl and chlorimuronethyl) in Digitaria insularis, the statistical methods provided by the dose-response curves and isobolograms were used. The concept of dose-response curves has been widely used to evaluate the results of herbicide experiments. However, the statistical approach around curves must be careful; considering the dose-response curves when they are not can greatly influence the comparison between molecules and affect the calculation of relative potency. Relative potency helps to understand what the power ratio is between molecules, this knowledge is fundamental for studies with herbicides in association. Knowing this, dose-response experiments were conducted on two types of substrates using Digitaria insularis as an indicator weed. The experiments were conducted in a greenhouse of the DuPont Research and Development Center in Paulínia (SP). For each molecule were applied, in pre-emergence, eight doses with four replicates each and four control plants on different substrates. Substrate A is pure commercial substrate (brand Tropstrato HT®); and substrate B is a mixture of sandy soil, sifted and contamination-free plus commercial substrate in the ratio 3:1 v/v. In this case it was evident the greater capacity of the sulfometuron-methyl to reduce the biomass of the species, the dose-response curves were described by the log-logistic model with the values of ED50 and the slopes of each curve varying freely, since the hypotheses tested in the different substrates of parallel curves were rejected. The calculated value of relative potency for the 50% response level between CLASSIC® (chlorimuron-ethyl) and CURAVIAL® (sulfometuron-methyl) herbicides under the conditions of this study was 8.596 and 44.047 on Substrate A and B respectively. From this information the same conditions of the previous experiment for the isoboles of the herbicides in association were used, five doseresponse curves were proposed, two curves for the isolated products and three curves for the associations in different ratios [25% : 75%); (50% : 50%); (75% : 25%)] chlorimuron-ethyl / sulfometuron-methyl, totaling 144 plots. Isoboles models were tested, the Concentration Additive model was significantly discarded, but was taken into account to theoretically test the degree of synergy or antagonism that more complex models could provide. The isobole model proposed by Hewlett and Plackett (1959) had a significant adjustment and interaction parameter smaller than 1 (λ = 0.33). The model that best fit the data was the one proposed by Vølund and the results also showed that under these conditions the association of sulfometuronmethyl with chlorimuron-ethyl was antagonistic; isoboles are potent tools for capturing and describing herbicide associations. So these results must be repeated in other conditions to validate the conclusions or to be executed in controlled laboratory conditions and to use living organisms of lesser complexity as a bioindicator.
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Interação entre fungos de solos e a formiga-cortadeira Atta sexdens (Linnaeus, 1758)

Nascimento, Mariela Otoni do 30 July 2015 (has links)
As formigas-cortadeiras (Hymenoptera: Formicidae), gêneros Atta e Acromyrmex, são as pragas mais importantes da silvicultura, encontradas exclusivamente nas Américas. Sua importância econômica se deve ao seu hábito alimentar de cortar material vegetal fresco – sendo algumas importantes espécies cultivadas - que serve de substrato para o fungo simbionte mutualista Leucoagaricus gongylophorus (Basidiomycota: Agaricales) o qual é cultivado em câmaras subterrâneas. As fêmeas fecundadas são responsáveis pela fundação de uma nova colônia e sofrem influência direta de microrganismos presentes no solo, assim existem evidências que fêmeas de Atta spp. recém-fecundadas evitam solos férteis, com alta carga microbiana e mesmo as áreas de matas para fundação dos seus ninhos. Os fungos entomopatogênicos e fungos antagonistas de L. gongylophorus, presentes naturalmente no solo, podem ser usados no controle biológico de formigas-cortadeiras. Os objetivos deste trabalho foram avaliar em laboratório o desenvolvendo de colônias jovens de Atta sexdens em contato com solos de área de mata e de área desnuda, realizar a bioprospecção de isolados de fungos antagonistas de L. gongylophorus (Trichoderma spp.), em solos da região de Gurupi - TO, e testar o efeito antagônico desses fungos contra L. gongylophorus. Após 106 dias da revoada, as operárias de A. sexdens das 36 colônias, logo que iniciado o experimento, removeram o solo em todos os tratamentos, e esse comportamento favoreceu a sobrevivência das colônias, apresentando uma taxa de sobrevivência de 91,67% durante as 13 semanas. Verificou-se que, após as colônias terem passado pelo período crítico de fundação, o tipo de solo parece exercer pouca influência na sobrevivência das operárias e das colônias. O solo de área de mata apresenta maior quantidade e diversidade de fungos filamentosos que o solo de área desnuda; A utilização de Tenebrio molitor como isca-viva é eficiente para bioprospecção por fungos entomopatogênicos. Todos os isolados de Trichoderma foram capazes de inibir o crescimento in vitro de L. gongylophorus; Trichoderma spirale isolado 2 apresentou crescimento micelial lento em placa de Petri e inibição contra L. gongylophorus, podendo este ser um isolado promissor em testes em campo. / The leaf-cutting ants (Hymenoptera: Formicidae), Atta and Acromyrmex genera, are the most important forest pests. They are found exclusively in Americas. Its economic importance is due to behavior to cut fresh plant material that serves as a substrate for the mutualistic symbiotic fungus Leucoagaricus gongylophorus (Basidiomycota: Agaricales) that are grown in underground chambers. Fertilized females are responsible for the founding of a new colony and they suffer direct influence of soil microorganisms. Therefore, newly fertilized females of Atta spp. should avoid fertile soils with high microbial load and even forested areas to found their nests. Entomopathogenic fungi and antagonists of L. gongylophorus are naturally present in the soil and they could be used in biological control of leaf-cutting ants. The objectives of this study were to evaluate and to compare the developing of young colonies of Atta sexdens in contact with soil from forested area and in contact with bare soils. Also, this and others procedures served to bioprospect antagonistic fungi of L. gongylophorus (Trichoderma spp.) from Gurupi region soil, and test the antagonistic effect of Trichoderma spp. against L. gongylophorus. In the first hours of start of experiments, Atta workers removed soil from colony recipients. This behavior could have favored colony survival, with a survival rate of 91,67 % during the 13 weeks. It was found that after the colonies have passed the critical period of foundation, the soil appears to exert little influence on the survival of workers and colonies. The soil from forested area had greater quantity and diversity of filamentous fungi than that from bare soil. The use of Tenebrio molitor as bait alive is efficient for bioprospecting by entomopathogenic fungi. All isolates of Trichoderma were able to inhibit in vitro growth of L. gongylophorus. Trichoderma spirale isolated 2 showed slow mycelial growth in Petri dish and strong level of inhibition against L. gongylophorus in vitro. So, this isolate is promising and should be tested in field.
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Compatibilidade entre tratamentos químico e biológico de sementes de feijão para controle de Fusarium oxysporum f. sp. phaseoli / Compatibility between chemical and biological treatments in common bean seeds to control Fusarium oxysporum f. sp. phaseoli

Ishizuka, Mariane Sayuri 01 April 2016 (has links)
Atualmente, a produtividade do feijoeiro comum (Phaseolus vulgaris L.) pode ser reduzida devido à ocorrência de doenças em todo o território nacional, destacando-se a murcha de fusário, causada por Fusarium oxysporum f. sp. phaseoli (Fop). No campo, o patógeno é disseminado a longas distâncias através das sementes infectadas e/ou contaminadas e a sua sobrevivência ocorre, principalmente, no solo. Os objetivos deste trabalho foram: avaliar a inibição do crescimento micelial de Fop por Trichoderma spp.; classificar a sensibilidade in vitro de Fop e Trichoderma spp., separadamente, a fungicidas e verificar a compatibilidade entre fungicidas químicos e biológicos para controle de Fop, presente nas sementes e no solo. Para avaliar a inibição do crescimento micelial de Fop, foram utilizados três isolados do patógeno, os quais foram confrontados, in vitro, com três isolados de Trichoderma spp. em testes de cultura pareada e produção de metabólitos voláteis a 20-22°C. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com cinco repetições para cada isolado de Trichoderma. Para a classificação da sensibilidade in vitro de Fop e Trichoderma a fungicidas, foram avaliados os mesmos isolados anteriormente utilizados. Foram comparados dez fungicidas, em doses entre 0 a 100 mg L-1 que foram ajustadas de acordo com a CI50 de cada fungicida. Com base na percentagem de inibição do crescimento micelial, foram estimados os valores da concentração inibitória de 50% (CI50) e 100% (CI100) e selecionaram-se os fungicidas compatíveis com Trichoderma spp. A compatibilidade entre tratamentos químico e biológico foi avaliada através da inoculação artificial de sementes de feijão com um isolado de Fop (IAC 11.299-1) e infestação do mesmo no solo. As sementes foram tratadas com os fungicidas fludioxonil, flutriafol e tiofanato metílico, e com os três produtos biológicos, separadamente e em misturas. Avaliou-se o efeito dos tratamentos por meio dos testes de sanidade, germinação, comprimento de plântulas, massa da matéria seca em laboratório e índice de velocidade de emergência e porcentagem de emergência em estufa não climatizada. O efeito protetor dos tratamentos foi verificado através do teste de transmissão do patógeno solo-planta. Todos os isolados de Trichoderma apresentaram antagonismo in vitro contra Fop. No teste de cultura pareada foi observada uma redução de 15 a 20% no crescimento micelial do patógeno. No teste de produção de metabólitos voláteis, o isolado T12-1086G05 foi responsável pela maior inibição do crescimento micelial de Fop (10 a 48%). Os testes de sensibilidade in vitro mostraram que tiofanato metílico, flutriafol e fludioxonil foram compatíveis com Trichoderma (CI50 > 2 mg L-1). Com exceção do flutriafol e do GF 422 isolados e em mistura, todos os tratamentos foram eficientes na erradicação de Fop nas sementes, sem afetar a sua qualidade fisiológica. No teste de transmissão, verificou-se que a incidência de Fop foi de 5 a 40% no hipocótilo e de 5 a 30% nas raízes de feijoeiro provenientes de sementes tratadas com os produtos. / Currently, the common bean (Phaseolus vulgaris L.) productivity can be reduced due to the occurrence of diseases in all over the country, especially Fusarium wilt, caused by Fusarium oxysporum f. sp. phaseoli (Fop). In the field, the pathogen is spread to long distances through infected and/or contaminated seeds and its survival occurs, mainly, in the soil. The objectives of this work were: to evaluate the micelial growth inhibition of Fop promoted by Trichoderma spp.; to classificate in vitro sensitivity of Fop and Trichoderma spp., separately, to fungicides and to verify the compatibility between chemical and biological fungicides to control Fop, applied on the seeds and on the soil. To evaluate the micelial growth inhibition of Fop, it was used three Fop isolates, which were in vitro confronted with three isolates of Trichoderma spp., by paired culture and antibiosis assays at 20-22°C. The experiments were conducted entirely casualized design, with five replications for each Trichoderma isolate. For the in vitro sensitivity classification, it was evaluated the same isolates of Fop and Trichoderma previously used. It was compared ten fungicides and the concentrations of 0 to 100 mg L-1, which were adjusted according to the IC50 of each fungicide. Based on the percentage of micelial growth inhibition, it was estimated the values of inhibitory concentration of 50% (IC50) and 100% ((IC100) and it was selected the compatible fungicides with Trichoderma spp. The compatibility between chemical and biological treatments were evaluated through artificial inoculation of common bean seeds with the Fop isolate IAC 11.299, following the infestation of the pathogen in the soil. Seeds were treated with fludioxonyl, flutriafol and tiofanate methyl, and with three biological products, separately and mixed. It was evaluated the treatment effects by the following assays: sanity, germination, seedling lenght, seedling dry matter in laboratory conditions and emergence speed rate and percentage of emergence in greenhouse conditions. The protective effect of the treatments was verified through the pathogen transmission experiment from soil to plant. All Trichoderma isolates showed in vitro antagonism against Fop. In the paired culture assay it was observed 15 to 20% reduction in the pathogen micelial growth. In the antibiosis assay, the isolate T12-1086G05 was responsible for the maximum micelial inhibition growth of Fop (10 to 48%). in vitro sensitivity experiments showed that thiofanate methyl, flutriafol and fludioxonyl were compatible with Trichoderma (IC50 > 2 mg L-1). Except the treatments with fluatrifol and GF 422 alone and in mixture, all the products were efficient in eradicating Fop in the seeds, without affect its physiological quality. In the transmission experiment, it was verified that the Fop incidence was 5 to 40% in the hypoticol and 5 to 30% in the common bean roots from seed treated with the products.

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