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

The Design and Validation of Virtual Trailblazing and Guidance Interfaces for the VTrail System

Iaboni, Daniel January 2009 (has links)
Wayfinding is a complex skill and the lack of tools supporting the specific sub-types of navigation hinders performance in large-scale virtual environments and consequently can slow the adoption of virtual technology for training. The VTrail System is designed to support virtual training by providing trainers (trailblazers) with the ability to create trails to guide users (trail followers) during training simulations. Without an effective interface to assist with creating trails, the task of trailblazing remains difficult. The objective of this research was to design a default interface for the VTrail System that adheres to the basic human factors engineering guidelines of simplicity, universality, and that does not interfere with primary task performance. Two studies (trailblazing, trail following), with a total of four experiments, were performed to evaluate and modify the proposed interfaces. The first experiments in each study determined that the proposed default interfaces are simple enough to use so as to not interfere with primary task performance. The second set of experiments found that, aside from the interface components included in the default interface, novice trailblazers and trail followers did not make use of any additional wayfinding aids when users were provided with the ability to create a custom interface. Secondary benefits included; the development of a novel approach for measuring spatial knowledge acquisition (called the SKAT), a set of criteria for qualitative analysis of trail quality in the form of the Trail Quality Questionnaire (referred to as TQQ), and improved understanding of the role individual differences, such as gender and spatial ability, in wayfinding performance. The high correlation between spatial ability score and performance on the SKAT suggests that the test provides a valid means of measuring spatial knowledge acquisition in a virtual environment. A measurable difference in the trail quality between males and females indicates that the TQQ can distinguish between trails of variable quality. Finally, there are measurable gender performance differences, despite similar levels in spatial ability between the genders. With the proposed interface designs the VTrail is closer to being ready to be incorporated as a support tool into virtual training programs. In addition, the designs for the VTrail System can be adapted for other platforms to support trailblazing in a range of applications, from use in military operations to providing an enhanced tourism experience. This research also serves as a starting point for future research projects on topics ranging from improving the design of the SKAT measure to understanding the effect of expertise on trailblazing performance.
2

The Design and Validation of Virtual Trailblazing and Guidance Interfaces for the VTrail System

Iaboni, Daniel January 2009 (has links)
Wayfinding is a complex skill and the lack of tools supporting the specific sub-types of navigation hinders performance in large-scale virtual environments and consequently can slow the adoption of virtual technology for training. The VTrail System is designed to support virtual training by providing trainers (trailblazers) with the ability to create trails to guide users (trail followers) during training simulations. Without an effective interface to assist with creating trails, the task of trailblazing remains difficult. The objective of this research was to design a default interface for the VTrail System that adheres to the basic human factors engineering guidelines of simplicity, universality, and that does not interfere with primary task performance. Two studies (trailblazing, trail following), with a total of four experiments, were performed to evaluate and modify the proposed interfaces. The first experiments in each study determined that the proposed default interfaces are simple enough to use so as to not interfere with primary task performance. The second set of experiments found that, aside from the interface components included in the default interface, novice trailblazers and trail followers did not make use of any additional wayfinding aids when users were provided with the ability to create a custom interface. Secondary benefits included; the development of a novel approach for measuring spatial knowledge acquisition (called the SKAT), a set of criteria for qualitative analysis of trail quality in the form of the Trail Quality Questionnaire (referred to as TQQ), and improved understanding of the role individual differences, such as gender and spatial ability, in wayfinding performance. The high correlation between spatial ability score and performance on the SKAT suggests that the test provides a valid means of measuring spatial knowledge acquisition in a virtual environment. A measurable difference in the trail quality between males and females indicates that the TQQ can distinguish between trails of variable quality. Finally, there are measurable gender performance differences, despite similar levels in spatial ability between the genders. With the proposed interface designs the VTrail is closer to being ready to be incorporated as a support tool into virtual training programs. In addition, the designs for the VTrail System can be adapted for other platforms to support trailblazing in a range of applications, from use in military operations to providing an enhanced tourism experience. This research also serves as a starting point for future research projects on topics ranging from improving the design of the SKAT measure to understanding the effect of expertise on trailblazing performance.
3

Trophic interactions on Zea spp. plants involving the herbivores Spodoptera frugiperda (J.E. Smith), Diatraea saccharalis (Fabricius) and the predator Doru luteipes Scudder / Interações tróficas em plantas Zea spp. envolvendo os herbivoros Spodoptera frugiperda (J. E. Smith), Diatrea saccharalis (Fabricius) e o predador Doru luteipes Scudder

Naranjo, Natalia Guevara 09 March 2017 (has links)
The earwigs (Dermaptera) contains mostly nocturnal insects, which are considered subsocial due to formation of aggregated family groups and maternal care. Species of Dermaptera have been shown to play an important role as generalist predators in different crop systems worldwide. Despite that, the knowledge about their behavior and insect-plant interactions remains poorly understood. The earwig Doru luteipes (Dermaptera: Forficulidae) is one of the most important generalist predators in different crops, especially in maize (Zea mays ssp. mays) by voraciously consuming eggs and larvae of Spodoptera frugiperda (Lepidoptera: Noctuidae) and Diatraea saccharalis (Lepidoptera: Crambidae), key pests in this crop. Maize is one of most produced cereals in the word. However, great losses are registered annually due to pest attacks, despite the use of pesticides. Studies have demonstrated that domesticated plants such as maize have reduced defenses against herbivores in detriment to intensely selecting for rapid growth and high yield, when compared with their wild ancestors\' species known as teosintes (Zea spp.). This thesis focuses on the study of the trophic interactions which occur in the system \'Zea plants - herbivores caterpillars - predator earwig\' and is divided in four chapters. In the Chapter 1 is present a general introduction and the thesis outline. In the Chapter 2, we studied through scent collection and multiple-choice bioassays, the communication between D. luteipes individuals which influences their predatory behavior. Our results indicate that earwigs can produce and use chemical cues by conspecifics to orientate them towards foraging resources. In the Chapter 3, we investigated the predation behavior of earwigs during photo- and scotophase and their preference for maize volatiles induced by S. frugiperda or D. saccharalis at different time intervals (early and old damage). Behavior, olfactometry bioassays and plant volatile collections were conducted. As was hypothesized, earwigs showed a predation activity only during night. Besides that, they were attracted by maize odors produced by both caterpillars and showed significant preference to early-damage odors over old-damage. Therefore, it is considered that early-damage volatiles (Green Leaf Volatiles-GLVs) could be the key compounds of D. luteipes attraction. In the last part (Chapter 4) was explored how domestication of Zea plants influences insect-plants interactions through plant defense. Experiments about food utilization by caterpillars, olfactometry bioassays and plant volatile collections were conducted. Interestingly, as in the previous chapter, we suggest that GLVs have an important role in earwig attraction. The results show that life-history of Zea plants influences plant defense and consequently the plant-insect interactions. In conclusion, our findings bring a new contribution to the knowledge about plant defenses in a tritrophic context and predatory strategies in D. luteipes, which would promote alternatives to optimize the conservation and biological control of pest by predators in the field. / As tesourinhas (Dermaptera) são em sua maioria insetos noturnos considerados sub-sociais devido ao cuidado maternal e à formação de grupos familiares agregados. Espécies de Dermaptera possuem um papel importante como predadores generalistas em diferentes culturas em todo mundo. Apesar disso, o conhecimento sobre seu comportamento e as interações inseto-planta permanecem pouco estudadas. A tesourinha Doru luteipes Scudder (Dermaptera: Forficulidae) é um dos predadores mais frequentes em diferentes culturas, especialmente no milho (Zea mays ssp. mays), devido ao voraz consumo de ovos e lagartas de Spodoptera frugiperda e Diatraea saccharalis, pragas chave nesta cultura. O milho é um dos cereais mais produzidos no mundo, embora grandes perdas sejam registradas anualmente devido ao ataque de pragas, apesar do uso de agroquímicos. Estudos recentes demostraram que plantas domesticadas tais como o milho têm reduzido suas defesas contra os herbívoros em detrimento à intensa seleção de cultivares de rápido crescimento e alta produtividade, quando comparados com seus ancestrais selvagens conhecidos como teosintos (Zea spp.). Esta tese foca no estudo das interações tróficas que ocorrem no sistema \'plantas Zea - lagartas herbívoras - tesourinhas predadoras\' e foi dividida em quatro capítulos. No Capítulo 1, apresenta-se uma introdução geral e o esboço da tese. No Capítulo 2, a partir da coleta de voláteis de adultos de D. luteipes e ensaios de múltipla escolha, foi estudada a comunicação química entre estes indivíduos que influencia o comportamento de predação. No Capítulo 3 foi investigado o comportamento de predação das tesourinhas durante a foto e escotofase, e a preferência delas pelos voláteis do milho induzidos por S. frugiperda ou D. saccharalis, em diferentes intervalos de tempo (dano recente ou dano tardio). As tesourinhas mostraram atividade predatória apenas durante a noite, e foram atraídas pelos odores do milho atacados pelas duas lagartas. O dano recente (voláteis de folhas verdes-VFVs) contêm os compostos chaves para a atração de D. luteipes. No Capítulo 4 foi explorado como a domesticação das plantas Zea influenciam as interações com insetos por meio das defesas de plantas. Assim como no capitulo anterior, os VFVs apresentaram um importante papel na atração das tesourinhas. Os resultados indicaram que a história de vida do gênero Zea influenciou as defesas das plantas e consequentemente, as interações inseto-planta. Em conclusão, o presente trabalho traz novas contribuições ao conhecimento sobre defesas de plantas num contexto tritrófico, bem como às estratégias de predação em D. luteipes, o qual pode gerar ferramentas para otimizar a conservação e controle biológico de pragas por predadores em campo.
4

Evoluce citlivosti ke stopovacím feromonům u termitů / Evolution of sensitivity to trail-following pheromones in termites

Száková, Barbora January 2021 (has links)
Eusocial insects evolved a sophisticated intraspecific communication, dominated by chemical signals, the pheromones. Termites (Isoptera) represent an excellent example in this respect, having a wide range of pheromones, such as trail-following, sex-pairing, alarm, and other pheromones. It is especially the former category of pheromones which is ubiquitous in termites and which was chemically characterized in many taxa across termite phylogeny. This allowed phylogenetic reconstruction of the chemical diversity of trail- following pheromones and calls for searching of evolutionary patterns of the sensitivity to these pheromones in various lineages across the tree of life, including the search for evolutionary scenario of the emergence of specific olfactory receptor proteins. In most species, the trail-following pheromones are represented by mono-, di- and tri-unsaturated fatty alcohols (3Z)-dodec-3-en-1-ol (DE), (3Z,6Z)-dodeca-3,6-dien-1-ol (DDE), and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol (DTE). My overall aim in this thesis was to contribute to the understanding of the evolution of olfactory detection of C12 fatty alcohol trail-following pheromones in termites. More specifically, my question was whether evolutionarily more basal clades (Kalotermes flavicollis and Neotermes cubanus from the family...

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