• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 132
  • 80
  • 16
  • 15
  • 14
  • 7
  • 6
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 330
  • 40
  • 29
  • 28
  • 28
  • 23
  • 23
  • 20
  • 18
  • 17
  • 17
  • 17
  • 17
  • 17
  • 15
  • 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.
101

A arte japonesa e a Ikebana na produção de Toshiro Kawase / The Japanese art and the Ikebana in Toshiro Kawases production

Freire, Adriana Bomeny 22 August 2014 (has links)
Esta pesquisa visou possibilitar o conhecimento da Ikebana como uma manifestação estética significativa, integrante da história da arte japonesa e que vem se disseminando pelo mundo. Para compreensão da sua estética, será demonstrado como exemplo o trabalho do artista contemporâneo Toshiro Kawase, o estudo do Zen e suas características. Toshiro Kawase é um artista especializado na arte da Ikebana, e suas obras resultaram em dois livros de âmbito internacional: Inspired Flower Arrangements (1990) e The Book of Ikebana (2000). A arte japonesa é baseada nos sentimentos e na simplicidade de expressão, que motivaram este povo a utilizar a natureza como suporte para executar memoráveis obras de arte. Ao longo da história, no oriente e no ocidente da mesma forma, a beleza das flores adicionou graça e charme na vida das pessoas. A pesquisa analisa a arte japonesa e sua ligação inseparável com a religião, abordando principalmente os aspectos do sagrado, o conceito do belo e a real função do artista de Ikebana. / This research intends to show Ikebana by being an esthetic manifestation of art, that been walking side by side with all stages of Art History. To understand the esthetic of Ikebana, will be demonstrated by example, the contemporary artist Toshiro Kawase, the Zen study and its characteristics. Toshiro Kawase is an artist specialized in Ikebanas Art, and his production inspired two international books: Inspired Flower Arrangements (1990) and The Book of Ikebana (2000). The Japanese art is based on emotions and expression simplicity that motivated this people to use the nature like a support to execute memorable works of art. In all parts of history of the art, in occident and in the orient at the same way, the beauty of flowers added grace and charm in peoples life. The question is: Why do Ikebanas art appeared only in Japan or related to Japanese? This research, analyses the Japanese art and its unbreakable link with religiosity, often the sacred aspect, the definition of beauty and the real functionality of the artist. This research also presents aspects of the principal objective of art, and how to do its communication purposing the perpetuation of his human experiences.
102

Adaptive Strategies for Foraging and Their Implications for Flower Constancy, or: Do Honey Bees Multitask?

Wagner, Ashley E 01 May 2014 (has links)
Classical experiments on honey bee time-memory showed that foragers trained to collect food at a fixed time of day return the following day with remarkable time-accuracy. Previous field experiments revealed that not all foragers return to a food source on unrewarded test days. Rather, there exist 2 subgroups: “persistent” foragers reconnoiter the source; “reticent” foragers wait in the hive for confirmation of source availability. To examine how these foragers contribute to a colony’s ability to reallocate foragers across sources with rapidly changing availabilities, foragers were trained to collect sucrose during a restricted window for several days and observed over 3 days throughout which the feeder was empty. In 2 separate trials, activity monitoring revealed a high level of activity apparently directed at other food sources. This “extracurricular” activity showed extensive temporal overlap with visits to the feeder, indicating that honey bees can manage at least 2 different overlapping time memories.
103

Aspectos taxonômicos e morfo-anatômicos das Bougainvillea Comm. ex Juss. (Nyctaginaceae) /

Cidrão, Bruno Bravos January 2019 (has links)
Orientador: Rosana Marta Kolb / Resumo: O gênero Bougainvillea Comm. ex Juss., pertencente a família Nyctaginaceae, é nativo da América Latina e é atualmente cultivado em vários outros países de clima tropical ou temperado. Suas espécies possuem brácteas coloridas que envolvem as inflorescências, atraem os polinizadores e ainda auxiliam na dispersão do fruto depois de seco. Possuem um antocarpo estriado e em forma de haste, diferente do restante dos membros da família, que possui antocarpos maiores ou ausentes. Das espécies de Bougainvillea, B. spectabilis e B. glabra são as mais citadas na literatura. Boa parte dos trabalhos com Bougainvillea é relacionada à anatomia do crescimento secundário diferenciado do gênero ou a estudos fitoquímicos. A anatomia, como ferramenta para estudos taxonômicos, tem sido empregada há muito tempo e tem auxiliado na distinção de espécies morfologicamente semelhantes. Neste trabalho, foi realizado um estudo da anatomia foliar das Bougainvillea com o intuito de obter dados que auxiliem na identificação das mesmas, além dos já citados na literatura; associado a uma monografia do gênero que visou esclarecer as divergências taxonômicas existentes entre as espécies. O estudo anatômico mostrou que elas têm em comum cutícula delgada, epiderme unisseriada, idioblastos contendo cristais na forma de ráfides e prismas, e tricomas tectores unisseriados; mas diferem no formato das células da epiderme, localização dos estômatos, tipo de mesofilo e formato das células que compõem os tricomas. São su... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The genus Bougainvillea Comm. ex Juss., belonging to the family Nyctaginaceae, is native to Latin America and is currently cultivated in several other tropical or temperate countries. Their species have colored bracts that surround the inflorescences, attract the pollinators and even aid fruit dispersion after drying. They have a striated, rod-shaped antocarp, different from the other family members, which have larger or absent antocarps. Among the Bougainvillea species, B. spectabilis and B. glabra are the most cited in the literature. Much of the work with Bougainvillea is related to the anatomy of differentiated secondary growth of the genus or phytochemical studies. Anatomy, as a tool for taxonomic studies, has been used for a long time and has aided in the distinction of morphologically similar species. In this work, a study of the foliar anatomy of the Bougainvillea was carried out with the purpose of obtaining data that help in the identification of its species, besides those already mentioned in the literature; associated to a monograph of the genus that aimed to clarify the taxonomic divergences between species. The anatomical study showed that they have in common thin cuticle, uniseriate epidermis, idioblasts containing crystals in the form of raphides and prisms and uniseriate trichomes; but differ in the shape of the epidermis cells, localization of stomata, mesophyll type and shape of the trichome cells. New synonyms are suggested for species B. glabra, B. praeco... (Complete abstract click electronic access below) / Mestre
104

Mechanisms of complex programmed patterns of anthocyanin pigment formation in Antirrhinum majus : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philsophy in Plant Molecular Biology at Massey University, Palmerston North New Zealand

Pathirana, Nilangani Nadyeshda January 2007 (has links)
Antirrhinum majus is a model plant used in flower pigmentation studies. Anthocyanin pigment production is mainly controlled by regulation of transcription of the anthocyanin biosynthetic genes. Two types of transcription factors, M Y B and bHLH, together with a WD40 type co-regulator have been shown to regulate the transcription of the anthocyanin biosynthetic genes. In antirrhinum, in addition to the wild type Rosea 1 phenotype, in which pigmentation occurs throughout the inner and outer epidermis of the petal , other complex pigmentation patterns are observed, such as anthocyanins being produced only in the outer (abaxial) epidermis of both lobes and upper tube region of the dorsal petals (roseadorsea phenotype). The major objective of this research project was to understand the genetic regulatory system leading to the development of the two different floral pigmentation patterns in antirrhinum as a means to understanding differential regulation of gene expression in similar cells. Promoter deletion analysis coupled with linker scanning mutagenesis identified the - 1 62 bp to - 1 20 bp region of the Rosea l promoter as i mportant for the regulation of the Rosea l gene. Four putative transcription factor-binding sites within this region : a Wbox, a pyrimidine box, a DOF and a WRKY transcription factor binding site were shown to be important for Rosea l gene regulation. Promoter deletion analysis carried out on the rosea ldorsea promoter showed that the proximal 1 87 bp deletion was, surprisingly, not responsible for the roseadorsea phenotype. Cloning and characterisation of the Rosea l promoter sequence from various Antirrhinum species and accessions verified this finding. The rosealdorsea promoter analysis also indicated that - 1 5 1 bp of the promoter was sufficient for its expression as well as for the maintenance of petal specific expression. The rosea ldorsea allele was also shown to encode a functional protein . In situ hybridisation analysis showed that Rosea l transcripts were present in the inner and outer epidermis of the petal tissue of both wild type and roseadorsea petal tissue. Vascular expression of the Roseal mRNA is indicative of regulation of this gene through sugar or hormonal cues. However, rosea ldorsea transcript levels (in roseadorsea) were much lower than Roseal (wild type). Lowered expression of rosea ldorsea transcripts may be responsible for the overall weak pigmentation in the roseadorsea flowers. Analysis of the intron sequences of the two alleles revealed that many sequence changes were present in the intron 2 of rosea l dorsea. These changes may lead to instability or the lower expression of the rosea l dorsea mRNA and may be responsible for the roseadorsea phenotype. Another possibility is that a fourth Myb gene may be responsible for the roseadorsea phenotype. The role of the Deficiens gene in direct regulation of Rosea l was analysed by RNAi and bioinformatics-based methods. The presence of potential MADS box binding sites in the intron 2 region of the Roseal allele indicated that Rosea l might be directly regulated by Deficiens. Initial experiments using transient assays did not support this suggestion. However, silencing of Deficiens in wild type antirrhinum buds led to the loss of anthocyanin pigments in the petals. Further analysis of the RNAi tissue using SEM revealed that the proper development of conical shaped epidermal cells was also affected . The RNAi tissue also developed chlorophyll pigments underscoring the plasticity of petal identity. This work demonstrated that proper expression of Deficiens is required throughout flowering for anthocyanin pigment production as well as maintenance of petal cell identity. The current investigation revealed that the higher order regulation of the Rosea l alleles in antirrhinum petals is much more complex than initially postulated.
105

Evolution of genetic mechanisms regulating reproductive development in plants : Characterisation of MADS-box genes active during cone development in Norway spruce

Sundström, Jens January 2001 (has links)
<p>The reproductive organs of conifers and angiosperms differ in morphology in several fundamental respects. The conifer Norway spruce <i>(Picea abies)</i> form pollen and seed cones from separate meristems whereas angiosperms bear bipartite flowers with sepals and petals surrounding two inner whorls of stamens and carpels. Despite these differences in morphology this thesis present data to suggest that reproductive development in conifers and angiosperms is regulated by a similar molecular mechanism. This implies an evolutionary conservation of the major mechanism for reproductive development since the origin of seed plants. </p><p>Flower organ identity in angiosperms is determined by regulatory genes belonging to the MADS-box gene family of transcription factors. This thesis presents the cloning and characterisation of four novel MADS-box genes from Norway spruce<i>.</i> Three of these genes <i>DAL11</i>, <i>DAL12</i> and <i>DAL13 </i>are most closely related to angiosperm B function genes <i>i.e.</i> genes required for petal and stamen development. <i>DAL11</i>, <i>12</i> and <i>13</i> all are specifically active in developing pollen cones, with different temporal and spatial expression pattern. Functional analysis in transgenic Arabidopsis and yeast suggest that the reproductive aspect of the B-function is conserved between conifers and angiosperms. The results also suggest that the B-function in conifers is separated into one shoot identity and one organ identity determinant. </p><p>A fourth gene presented;<i> DAL10,</i> is specifically expressed in vegetative parts of pollen- and seed cones. Phylogenetically <i>DAL10</i> is not closely related to any of the known angiosperm clades, but rather forms a separate clade with other gymnosperm genes, suggesting a gymnosperm specific function. We suggest that the <i>DAL10</i> activity reflects a function in the determination of the reproductive shoot.</p>
106

Evolution of genetic mechanisms regulating reproductive development in plants : Characterisation of MADS-box genes active during cone development in Norway spruce

Sundström, Jens January 2001 (has links)
The reproductive organs of conifers and angiosperms differ in morphology in several fundamental respects. The conifer Norway spruce (Picea abies) form pollen and seed cones from separate meristems whereas angiosperms bear bipartite flowers with sepals and petals surrounding two inner whorls of stamens and carpels. Despite these differences in morphology this thesis present data to suggest that reproductive development in conifers and angiosperms is regulated by a similar molecular mechanism. This implies an evolutionary conservation of the major mechanism for reproductive development since the origin of seed plants. Flower organ identity in angiosperms is determined by regulatory genes belonging to the MADS-box gene family of transcription factors. This thesis presents the cloning and characterisation of four novel MADS-box genes from Norway spruce. Three of these genes DAL11, DAL12 and DAL13 are most closely related to angiosperm B function genes i.e. genes required for petal and stamen development. DAL11, 12 and 13 all are specifically active in developing pollen cones, with different temporal and spatial expression pattern. Functional analysis in transgenic Arabidopsis and yeast suggest that the reproductive aspect of the B-function is conserved between conifers and angiosperms. The results also suggest that the B-function in conifers is separated into one shoot identity and one organ identity determinant. A fourth gene presented; DAL10, is specifically expressed in vegetative parts of pollen- and seed cones. Phylogenetically DAL10 is not closely related to any of the known angiosperm clades, but rather forms a separate clade with other gymnosperm genes, suggesting a gymnosperm specific function. We suggest that the DAL10 activity reflects a function in the determination of the reproductive shoot.
107

The Evolution and Genetics of Reinforcement in Phlox Drummondii

Hopkins, Robin January 2010 (has links)
<p>One of the major goals of evolutionary biology is understanding the process of species formation. There is particular interest in how selection can favor species formation through the process of reinforcement. When two diverging taxa produce maladaptive hybrids, selection will favor greater reproductive isolation between the taxa. Reinforcement often results in a pattern of reproductive character displacement, which is defined as two species having greater reproductive isolation in sympatry then in allopatry. Floral-color divergence in the native Texas wildflower, Phlox drummondii, constitutes one of the best documented cases of reinforcement in plants. P. drummondii and a closely related species, P. cuspidata produce similar light-blue flowers throughout the allopatric parts of their ranges. However, in the area of sympatry P. drummondii has dark-red flowers, which has been shown to decrease hybridization between the two species. In the following work, I investigate the causes and consequences of the process of reinforcement and the pattern of character displacement in P. drummondii. First, I identify the genetic basis of the flower color variation as regulatory changes in two genes controlling the type and amount of anthocyanin floral pigments. I then evaluate neutral genetic variation across the range of P. drummondii and conclude there is extensive gene flow between allopatric and sympatric areas of the range, which indicates that selection and not genetic drift is responsible for the flower color variation. By investigating genetic variation at the loci underlying flower color variation I find a molecular signature of a selective sweep at one of the two flower color loci, further indicating that selection is responsible for this flower color variation. Finally, I measure selection on flower color in both sympatry and allopatry. I find no evidence that flower color variation is a response to ecological character displacement or local adaptation in the area of sympatry. I find evidence of pollinator preference for the ancestral allopatric flower color in allopatry, which may explain the persistence of the pattern of character displacement. These investigations of reproductive character displacement and reinforcement address important areas of research in evolutionary biology including the genetic basis of adaptation, the formation of species, and pleiotropy and conflicting selection pressures in species.</p> / Dissertation
108

Effects of Nutrient Supply and Cooling on Growth, Flower Bud Differentiation, and Propagation of the Nobile Dendrobium Orchid

Yen, Christine Yung-Ting 15 May 2009 (has links)
Studies of Dendrobium Sea Mary ‘Snow King’ investigated the effect of nutrient termination (1 Aug., 1 Sept., or 1 Oct.) and reapplication [at the beginning, in the middle, immediately after, or 2 weeks after (relative to cooling), or no nutrient reapplication] on growth and flowering, quantified cooling requirements (10, 13, 15, or 18 °C for 2 to 6 weeks) for flowering, and determined optimum nutrient termination (on the three above dates) and nutrient rate (0.33, 0.67, or 1.33 g•L-1 15N-2.3P-12.9K) for producing single-node cuttings. Regardless of reapplication stages, nutrient termination on 1 Oct. caused taller plants with more nodes, more leaves, more flowering nodes, more total flowers, and fewer aborted flowers than those being terminated earlier. Only buds protruding above 2 mm from pseudobulb surface showed differentiated floral structures. Plants with 1 Aug. nutrient termination had larger flower primordia than those with 1 Oct., indicating flower differentiated earlier or faster with an earlier nutrient termination. No reversion of reproductive to vegetative buds arose due to either late nutrient termination or resumption of nutrients during cooling. Interactions between temperature and cooling duration were significant on time required for anthesis and full flowering, recorded from either beginning or completion of cooling, average flower number per flowering node, and flower diameter. Increasing cooling duration from 2 to 6 weeks led plants to reach anthesis and full flowering faster after cooling; however, the increasing cooling duration actually extended total time for producing flowering crops. Increasing temperature from 10 to 15 °C accelerated flowering after cooling. Plants had more flowering nodes and total flowers when cooled at 10 to 15 °C than at 18 °C. The results suggest that 3 weeks of cooling at 13 or 15 °C produce quality flowering plants that require less time to reach flowering. Plants fertilized at 0.67 or 1.33 g•L-1 were taller with 18% more nodes and more leaves than those receiving 0.33 g•L-1. Increasing nutrient rate with prolonged supply to the plants caused more single-node cuttings to grow into vegetative shoots for propagation, fewer cuttings to transition to flowering nodes, and less flower abortion to occur.
109

none

Wang, Chung-wei 24 June 2008 (has links)
In the purpose of this study we examine the long run relationship between the flower wholesale markets in Taiwan by the theory of Park (2007). The market integration is analyzed from the viewpoint of the Law of One Price (LOP). The LOP means that the products flow from the lower price markets to the higher price ones without transaction cost utill everywhere have the same price. However, in a situation that the transaction cost exists, the assumption of LOP is questionable. When the price difference between two markets exceeds the transaction cost, there is an arbitrage opportunity. This study examine the relationship between the flower wholesale markets in Taiwan by threshold cointegration theory. The result is that there indeed exists long run relationship and threshold effects. In addition, we consider a time-varing threshold cointegration model in Park (2007), to see whether there are different arbitrage behavious depending on the season between the flower wholesale markets. Finally, we have a result that the same price gap between markets in different season will be in different regime because of the change of the value of threshold. And it causes the seasonal arbitrage behavious.
110

Reproductive dynamics of coral reef biota at the Flower Gardens /

Hagman, Derek Kristian, January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 173-201). Available also in a digital version from Dissertation Abstracts.

Page generated in 0.0534 seconds