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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.
201

A perda de área foliar e sua relação com o gênero Ectatomma (Formicidae: Ectatomminae) em uma comunidade de cerrado / The loss of leaf and its relation to genus Ectatomma (Formicidae:Ecatomminae) in a cerrado community

Graziella Diogenes Vieira Marques Erdogmus 01 March 2010 (has links)
A perda de área foliar, em sua maior parte resultante da ação de herbívoros, é um dos fatores que regulam o sucesso reprodutivo de uma planta e indiretamente de todos os consumidores relacionados na comunidade. A maior parte dos estudos feitos com perda foliar e herbivoria são pontuais, ou seja, referem-se a uma ou poucas espécies vegetais. Para os cerrados, a savana tropical brasileira, a maior savana em extensão e diversidade no mundo, não há nenhum estudo que investigue a dinâmica de perda de área foliar ao longo do tempo na comunidade, considerando os fatores climáticos e fenológicos que podem influenciar este processo, além da presença dos principais predadores de herbívoros atrópodes na vegetação de cerrado, as formigas, sendo este o principal objetivo do presente estudo. O estudo foi desenvolvido em uma área de reserva de Cerrado de 628 ha, situada em Uberlândia, MG (18º59S, 48º18O), tendo os dados sido coletados de janeiro a dezembro de 2007 (bimestralmente) e de 2008 (mensalmente). Foram estabelecidos aleatoriamente na área de cerrado sensu stricto da reserva, 15 quadrantes de 10m x 10m onde todos os indivíduos com diâmetro à altura do peito igual ou superior a três centímetros foram marcados e incluídos na amostra. Em cada quadrante observou-se (sem remoção), seis folhas (escolhidas aleatoriamente duas da parte alta, duas da parte mediana e duas de ramos mais baixos), por planta de cada espécie, sendo registrada a porcentagem de área foliar perdida. Foram amostrados um total de 1006 indivíduos distribuídos em 82 espécies e 34 famílias. A espécie Ouratea spectabilis (137 indivíduos) foi a mais abundante na área de estudo, seguida de Banisteriopsis malifolia (122), Machaerium acutifolium (59) e Tabebuia ochracea (41). A perda de área foliar variou significativamente ao longo do tempo (meses) e entre as famílias e espécies de plantas. Os meses mais secos do ano apresentaram a maior perda de área foliar tanto em 2007 (abril, junho e agosto) quanto em 2008 (de maio a agosto). Os fatores climáticos influenciaram significativamente a perda de área foliar, pois ela variou ao longo do tempo. Portanto, os resultados do presente estudo indicaram que a perda de área foliar da comunidade de plantas de cerrado varia sazonalmente e ocorre com maior intensidade na estação seca. Fatores abióticos como temperatura e precipitação influenciam a fenologia das espécies de plantas, que buscam o melhor momento para maximizar seu desenvolvimento e evitar que inimigos naturais causem perdas significativas para sua sobrevivência e sucesso reprodutivo. As características de cada espécie promovem diferenças na perda de área foliar, devido às defesas e/ou associações mutualísticas que possuem. A presença de nectários extraflorais associados às formigas desempenha um papel significativo para as plantas. Dentre os fatores bióticos, a presença de ninhos de formigas Ectatomma teve um impacto positivo para as plantas reduzindo a perda de área foliar. / The loss of leaf area, mostly resulting from the action of herbivores is one of the factors that regulate the reproductive success of a plant and indirectly to all consumers connected to the community. Most studies of herbivory and leaf loss are punctual, i.e., refer to one or a few plant species. In the cerrado, a tropical savanna in Brazil, the largest savanna in scope and diversity in the world, there are no studies to investigate the dynamics of loss of leaf area over time in the community, considering the climatic factors, phenology and carnivorous ants that can influence this process, which is the main objective of this study. The study was conducted in a closed area of 628 ha of Cerrado, located in Uberlandia, Brazil (18 º 59\'S, 48 18\'W) and the data were collected from January to December 2007 (bimonthly) and 2008 (monthly). Were established randomly in the area of cerrado of the reserve, 15 quarters of 10m x 10m where all trees with diameter at breast height greater than or equal to three centimeters were marked with numbered label and sampled. In each quadrant was observed (without removal), six leaves (randomly chosen two of high part, two of the middle, and two of the lower branches), in plant species, and recorded the percentage of leaf area lost. We sampled a total of 1006 individuals belonging to 82 species and 34 families. The species Ouratea spectabilis (137 individuals) was the most abundant in the study area, followed by Banisteriopsis malifolia (122), Machaerium acutifolium (59) and Tabebuia ochracea (41). The loss of leaf area varied significantly over time (months) and between families and species of plants. The driest months of the year showed the greatest loss of leaf area in both 2007 (April, June and August) and in 2008 (May-August). Climatic factors also significantly influenced the loss of leaf area, as it varied over time, depending on the rainfall and temperature variation. Therefore, the results of this study indicated that the loss of leaf area community of cerrado plants varies seasonally and occurs mostly in the dry season. Abiotic factors like temperature and rainfall influence the phenology of species of plants, seeking the best time to maximize their development and prevent natural enemies result in significant losses for their survival and reproductive success. The characteristics of each species promote differences in leaf area loss due to defenses and / or mutualistic associations they have. The presence of extrafloral nectaries associated with ants play a significant role for plants. For this reason, among the biotic factors, the presence of Ectatomma nests had a significant positive impact on reducing the loss of leaf area, since these ants are predators of herbivores.
202

[en] AN APPLICATION OF ANT COLONY ALGORITHMS TO VEHICLE ROUTING PROBLEMS WITH TIME WINDOWS / [pt] UMA APLICAÇÃO DE ALGORITMOS DE COLÔNIAS DE FORMIGAS EM PROBLEMAS DE ROTEIRIZAÇÃO DE VEÍCULOS COM JANELAS DE TEMPO

RAFAEL LORENZO SANTOS 25 April 2007 (has links)
[pt] Muitos avanços da ciência foram obtidos a partir da observação da natureza. Milênios de seleção natural e evolução fizeram com que certos seres vivos desenvolvessem habilidades e características realmente notáveis, e que ainda hoje surpreendem pela sua complexidade e adaptabilidade. Alguns ramos da ciência fazem uso constante da observação intensiva dessas características, na tentativa de reproduzi-las em um ambiente controlado, com o objetivo de desenvolver métodos e ferramentas nelas baseados. Exemplos de métodos desenvolvidos dessa forma são os algoritmos de colônias de formigas. Sistemas de colônias de formigas (Ant Colony Systems - ACS) são modelos matemáticos baseados no comportamento de formigas quando imersas em colônias de indivíduos semelhantes. Formigas são indivíduos simples, porém capazes de interagir entre si, obtendo muitos benefícios desta prática. Estes modelos são muito úteis na resolução de grandes problemas de otimização combinatória, geralmente muito complexos para serem resolvidos por métodos exatos de otimização e representam um incipiente e importante campo de estudos da engenharia de produção. Este trabalho se propõe a descrever alguns algoritmos de colônias de formigas, utilizados em problemas de otimização combinatória/discreta. Particularmente, o foco do trabalho será na aplicação destes algoritmos no problema de roteirização de veículos com janelas de tempo. Uma forma de implementação do algoritmo no ambiente Matlab será proposta e testada em problemas padrão usados como benchmarking na literatura. / [en] Many advances in science were achieved from the observation of nature. Thousands of years of natural selection and evolution made certain living beings develop notable abilities and characteristics, that still nowadays surprise us with their complexity and adaptability. Some fields of science make constant use of intensive observation of these characteristics, in order to reproduce them in a controlled environment, with the objective of developping methods and tools based on them. Examples of methods developped this way are ant colony algorithms. Ant Colony Systems are mathematical models based on the behavior of ants when immersed in colonies of likely individuals. Ants are simple individuals, however capable of interacting with each other, obtaining benefits from this practice. These models are very useful in solving large combinatory optimization problems, usually too complex to be solved by exact optimization methods, and represent an important and incipient field of study in production engineering. This work aims to describe some ant colony algorithms, used in combinatory/discrete optimization problems. Particularly, the focus of this work will be in the application of these algorithms to the vehicle routing problem with time windows. A form of implementation of the algorithm in Matlab environment will be proposed and tested in standard problems used as benchmarking in the literature.
203

A perda de área foliar e sua relação com o gênero Ectatomma (Formicidae: Ectatomminae) em uma comunidade de cerrado / The loss of leaf and its relation to genus Ectatomma (Formicidae:Ecatomminae) in a cerrado community

Erdogmus, Graziella Diogenes Vieira Marques 01 March 2010 (has links)
A perda de área foliar, em sua maior parte resultante da ação de herbívoros, é um dos fatores que regulam o sucesso reprodutivo de uma planta e indiretamente de todos os consumidores relacionados na comunidade. A maior parte dos estudos feitos com perda foliar e herbivoria são pontuais, ou seja, referem-se a uma ou poucas espécies vegetais. Para os cerrados, a savana tropical brasileira, a maior savana em extensão e diversidade no mundo, não há nenhum estudo que investigue a dinâmica de perda de área foliar ao longo do tempo na comunidade, considerando os fatores climáticos e fenológicos que podem influenciar este processo, além da presença dos principais predadores de herbívoros atrópodes na vegetação de cerrado, as formigas, sendo este o principal objetivo do presente estudo. O estudo foi desenvolvido em uma área de reserva de Cerrado de 628 ha, situada em Uberlândia, MG (18º59S, 48º18O), tendo os dados sido coletados de janeiro a dezembro de 2007 (bimestralmente) e de 2008 (mensalmente). Foram estabelecidos aleatoriamente na área de cerrado sensu stricto da reserva, 15 quadrantes de 10m x 10m onde todos os indivíduos com diâmetro à altura do peito igual ou superior a três centímetros foram marcados e incluídos na amostra. Em cada quadrante observou-se (sem remoção), seis folhas (escolhidas aleatoriamente duas da parte alta, duas da parte mediana e duas de ramos mais baixos), por planta de cada espécie, sendo registrada a porcentagem de área foliar perdida. Foram amostrados um total de 1006 indivíduos distribuídos em 82 espécies e 34 famílias. A espécie Ouratea spectabilis (137 indivíduos) foi a mais abundante na área de estudo, seguida de Banisteriopsis malifolia (122), Machaerium acutifolium (59) e Tabebuia ochracea (41). A perda de área foliar variou significativamente ao longo do tempo (meses) e entre as famílias e espécies de plantas. Os meses mais secos do ano apresentaram a maior perda de área foliar tanto em 2007 (abril, junho e agosto) quanto em 2008 (de maio a agosto). Os fatores climáticos influenciaram significativamente a perda de área foliar, pois ela variou ao longo do tempo. Portanto, os resultados do presente estudo indicaram que a perda de área foliar da comunidade de plantas de cerrado varia sazonalmente e ocorre com maior intensidade na estação seca. Fatores abióticos como temperatura e precipitação influenciam a fenologia das espécies de plantas, que buscam o melhor momento para maximizar seu desenvolvimento e evitar que inimigos naturais causem perdas significativas para sua sobrevivência e sucesso reprodutivo. As características de cada espécie promovem diferenças na perda de área foliar, devido às defesas e/ou associações mutualísticas que possuem. A presença de nectários extraflorais associados às formigas desempenha um papel significativo para as plantas. Dentre os fatores bióticos, a presença de ninhos de formigas Ectatomma teve um impacto positivo para as plantas reduzindo a perda de área foliar. / The loss of leaf area, mostly resulting from the action of herbivores is one of the factors that regulate the reproductive success of a plant and indirectly to all consumers connected to the community. Most studies of herbivory and leaf loss are punctual, i.e., refer to one or a few plant species. In the cerrado, a tropical savanna in Brazil, the largest savanna in scope and diversity in the world, there are no studies to investigate the dynamics of loss of leaf area over time in the community, considering the climatic factors, phenology and carnivorous ants that can influence this process, which is the main objective of this study. The study was conducted in a closed area of 628 ha of Cerrado, located in Uberlandia, Brazil (18 º 59\'S, 48 18\'W) and the data were collected from January to December 2007 (bimonthly) and 2008 (monthly). Were established randomly in the area of cerrado of the reserve, 15 quarters of 10m x 10m where all trees with diameter at breast height greater than or equal to three centimeters were marked with numbered label and sampled. In each quadrant was observed (without removal), six leaves (randomly chosen two of high part, two of the middle, and two of the lower branches), in plant species, and recorded the percentage of leaf area lost. We sampled a total of 1006 individuals belonging to 82 species and 34 families. The species Ouratea spectabilis (137 individuals) was the most abundant in the study area, followed by Banisteriopsis malifolia (122), Machaerium acutifolium (59) and Tabebuia ochracea (41). The loss of leaf area varied significantly over time (months) and between families and species of plants. The driest months of the year showed the greatest loss of leaf area in both 2007 (April, June and August) and in 2008 (May-August). Climatic factors also significantly influenced the loss of leaf area, as it varied over time, depending on the rainfall and temperature variation. Therefore, the results of this study indicated that the loss of leaf area community of cerrado plants varies seasonally and occurs mostly in the dry season. Abiotic factors like temperature and rainfall influence the phenology of species of plants, seeking the best time to maximize their development and prevent natural enemies result in significant losses for their survival and reproductive success. The characteristics of each species promote differences in leaf area loss due to defenses and / or mutualistic associations they have. The presence of extrafloral nectaries associated with ants play a significant role for plants. For this reason, among the biotic factors, the presence of Ectatomma nests had a significant positive impact on reducing the loss of leaf area, since these ants are predators of herbivores.
204

A Parametric Framework for Modeling and Manufacturing an Ant Neck Joint

Bischof, Ryan January 2020 (has links)
No description available.
205

Analysis of feeding techniques of a patch antenna array for 5G NR / Analysis of feeding techniques of a patch antenna array for 5G NR

Kivk, Ji­ January 2021 (has links)
Tato diplomov prce se zabv anal­zou rznch napjec­ch struktur pro 2x2 fl­Äkov© antenn­ pole. Evaluace prob­h na stedn­ frekvenci 25.5GHz, kter spad do psma piazen©ho pt© generaci mobiln­ch komunikaÄn­ho standardu. Zvolen© napjec­ struktury byly napjen­ bl­zkm polem, napjen­ aperturou a napjen­ mikropskem.
206

Ant-Inspired Control Strategies for Collective Transport by Dynamic Multi-Robot Teams with Temporary Leaders

January 2020 (has links)
abstract: In certain ant species, groups of ants work together to transport food and materials back to their nests. In some cases, the group exhibits a leader-follower behavior in which a single ant guides the entire group based on its knowledge of the destination. In some cases, the leader role is occupied temporarily by an ant, only to be replaced when an ant with new information arrives. This kind of behavior can be very useful in uncertain environments where robot teams work together to transport a heavy or bulky payload. The purpose of this research was to study ways to implement this behavior on robot teams. In this work, I combined existing dynamical models of collective transport in ants to create a stochastic model that describes these behaviors and can be used to control multi-robot systems to perform collective transport. In this model, each agent transitions stochastically between roles based on the force that it senses the other agents are applying to the load. The agent’s motion is governed by a proportional controller that updates its applied force based on the load velocity. I developed agent-based simulations of this model in NetLogo and explored leader-follower scenarios in which agents receive information about the transport destination by a newly informed agent (leader) joining the team. From these simulations, I derived the mean allocations of agents between “puller” and “lifter” roles and the mean forces applied by the agents throughout the motion. From the simulation results obtained, we show that the mean ratio of lifter to puller populations is approximately 1:1. We also show that agents using the role update procedure based on forces are required to exert less force than agents that select their role based on their position on the load, although both strategies achieve similar transport speeds. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020
207

Living in the Droneworld: A Re-Assessment of Realist Conception of Sovereignty / Ve světě dronů: Přehodnocení realistického pojetí suverenity

Veselý, Tomáš January 2020 (has links)
This work assesses the evolving link between drone warfare and the concept of state sovereignty. In doing so, the paper critiques the existing realist and neo- realist discourses that maintain anthropocentric and state-centric assumptions in the analysis of not only the field of Security Studies, but International Relations as a whole. The phenomenon of drone warfare proves the opposite of such assumptions. The role of the state, and indeed the human, is continually decreasing with the involvement of hybrid actors. The drone is the embodiment of complex hybridity combining human and non-human actors alike. To better understand the contemporary execution of sovereignty, particularly in its role of maintaining the monopoly on violence, this paper will explore the premises of post-human perspectives in International Relations. In particular, this paper is inspired by the insights of Actor-Network Theory (ANT), which emphasises equal analysis of human and non-human actors. Sovereignty remains a relevant topic, but through the involvement of hybrid actors, it is devolving into a seemingly arbitrary distribution of violence. The role of human actors in drone warfare is decreasing with the technological improvement of military drones and the military demand for increased drone autonomy. As a result,...
208

Neuroanatomical and neurochemical correlates of senescence and social role in the ant Pheidole dentata

Giraldo, Ysabel Milton 12 March 2016 (has links)
Sociality shapes patterns of senescence, evidenced by the remarkable lifespan plasticity of social insect queens and workers. Ants, exemplars of eusociality, provide diverse systems to explore the sociobiology of senescence by examining how sterile workers partition colony labor over their lifespans, and how neurobiological factors affect transitions among social roles and age-related task performance efficacies. Integrating sociobiology, senescence theory, and neurobiology, I examined the relationship of chronological age and social behavior during the ~140-day lifespan of workers of the ant Pheidole dentata. I critically analyzed programmed senescence in respect to the sociobiology of worker longevity and evaluated how large colony size achieved through selection for extended worker lifespan enhances colony fitness. My study found no support for worker programmed senescence. Further testing senescence theory, I determined if workers declined behaviorally as they aged due to increased apoptotic cell death and changes in synaptic complexes associated with higher-order processing in the brain. Using robust behavioral assays I found aging was not correlated with declines in sensory responsiveness or motor functions associated with foraging, nursing, and prey-capture tasks, or activity level and phototaxis. Old minor workers (95 days) followed pheromone trails for greater distances than 20-day old minors and showed higher activity levels, suggesting improvement in behavioral performance. Neural substrates likely underscoring task performance were maintained with age: synaptic complex density was constant and apoptosis was unchanged with age. Sensory and motor control brain regions did not show age-related increases in neurodegeneration. Worker spatial location predicted social role independent of age: foragers exhibited higher activity levels and more aggressive predatory behavior than nurses. Serotonin and dopamine titers increased from 20 to 120 days but showed no clear correlation with social role. Pharmacological manipulations of brain serotonin had no effect on brood care, predatory response, activity, or phototaxis. Finally, I assessed arborization of a serotonergic neuron hypothesized to underscore task performance to determine how aging across subcastes influences neuronal structure. Major workers showed greater branching complexity than minors and an age-related increase in arbor complexity. P. dentata workers appear to show negligible behavioral and neural senescence throughout their lifespans.
209

Evolutionary relationships between pollination and protective mutualisms in the genus Macaranga (Euphorbiaceae) / オオバギ属植物(トウダイグサ科)における送粉共生と被食防衛共生の進化的関係

Yamasaki, Eri 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18113号 / 理博第3991号 / 新制||理||1576(附属図書館) / 30971 / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 酒井 章子, 教授 山内 淳, 准教授 永益 英敏 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
210

Post-Literacy: Designing Writing Curricula around Emerging Literate Activities

Bowers, George Bret 15 April 2013 (has links)
No description available.

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