• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 19
  • 10
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 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

Resistance to Three Common Herbicides in Chameleon Plant (Houttuynia Cordata Thunb.), a Highly Invasive Exotic Species

Ice, David 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Chameleon plant (Houttuynia cordata Thunb.) is native to Southern and Southeastern Asia. It can reproduce sexually through seeds and asexually through rhizomes and is invasive in multiple countries including the U.S. There has been much research on H. cordata as a medicinal species, and its potential as an invasive species is well documented. However, its herbicidal resistance has not previously been quantified. The objective of this study is to assess H. cordata’s resistance to herbicides. This study consisted of two rounds of tests to examine the resistance of H. cordata plants to three commonly used herbicides: SpeedZone, Weed-B-Gon, and Roundup. Two concentrations of each herbicide were used during each trial in the study: the recommended concentration and twice the recommended concentration. Herbicide treatments were applied outside the greenhouse. Herbicides were sprayed uniformly on the plants until the herbicide was dripping off the leaves. The growth of the treated plants was then monitored in the greenhouse. The herbicides generally reduced growth of the plants temporarily. However, plant extermination was not achieved. Plant samples from all herbicidal treatments regrew from rhizomes after all herbicide treatments. Results from the study showed that H. cordata could not be controlled by the recommended concentrations of herbicides commercially available for horticultural uses in the U.S. Doubling the recommended herbicide concentration was also ineffective in exterminating H. cordata plants. This research clearly showed that H. cordata has the potential to become a highly invasive species with the potential to negatively affect the ecological integrity of many communities in the U.S.
2

Efeito de extratos de plantas no controle do estresse oxidativo em ovinos confinados alimentados com dieta com elevada proporção de concentrado / Plant extracts effect on the control of oxidative stress in feedlot sheep fed diets with high concentrate

Lima, Tiago Ronimar Ferreira 15 August 2016 (has links)
O uso de dietas com elevado teor de concentrado para intensificar a produção de carne de ovinos pode influenciar a homeostase oxidativa do animal, com efeito no seu desempenho e na qualidade da carne. Para buscar meios alternativos, foram testados antioxidantes convencionais em comparação com extratos de plantas no controle do estresse oxidativo em cordeiros alimentados com dieta exclusiva de concentrado. Foram utilizados 48 cordeiros machos Dorper x Santa Inês com peso inicial de 20 ± 1,49 kg desmamados aos 60 dias e alojados em baias individuais e alimentados durante 60 dias com dieta exclusiva de concentrado, composta por 80% milho grão inteiro e 20% pelete proteico, com os tratamentos diferindo apenas na adição dos antioxidantes. Os tratamentos foram controle, sem adição de antioxidante, extrato de plantas com adição de 4 mg/kg de Macleya cordata e Magnolia oficcinalis, tratamento vitamina E e selênio nas quantidades 100UI/kg e 0,1 mg/kg, respectivamente e tratamento extrato de plantas + vitamina E e selênio, nas mesmas quantidades anteriores. A alimentação e a sobra foram pesadas diariamente para determinação de matéria seca e eficiência alimentar. Os animais foram pesados no início do experimento e a cada 14 dias para acompanhamento do desempenho. Foram perdidas duas parcelas experimentais. Durante o período experimental foram realizadas três colheitas de sangue para avaliação de parâmetros oxidativos e proteicos. Após o abate, foram retiradas amostras para análise em painel expositor refrigerado do Longissimus dorsi durante oito dias para influência da estabilidade oxidativa na cor. Houve influência no peso final, ganho diário, peso de carcaça e teor de Se no músculo L.dorsi para tratamentos com adição de vitamina E e Se. Não houve efeito de tratamento para proteínas sanguíneas, indicando que os animais estavam saudáveis durante o experimento. O uso de extrato de plantas teve efeito similar ao dos antioxidantes convencionais e pode ser usada no controle do estresse oxidativo. / The use of high concentrate diets to intensify sheep meat production can influence the oxidative homeostasis of the animal, influencing performance and meat quality. In order to find alternative antioxidants this experiment was carried out to test conventional antioxidants in comparison with plant extracts in the control of oxidative stress in lambs fed exclusively a concentrate diet. Forty-eight male lambs Dorper x Santa Inês with initial weight of 20 ± 1.49 kg weaned at 60 days and housed in individual pens were used. The animals were fed a concentrate diet consisting of 80% whole corn grain and 20% protein pellet, and the treatments differed only in the addition of the antioxidants during 60 days. The treatments were control, no added antioxidant, treatment with plant extract with inclusion of 4 mg / kg plant extract of Macleya cordata and Magnolia oficcinalis, treatment with vitamin E and selenium in amounts of 100 IU / kg and 0.1 mg / kg, respectively, and treatment plant extract + vitamin E and selenium, in the same previous amounts cited. The feed and orts were weighed daily to determine the dry matter intake and feed efficiency. The animals were weighed at the beginning of the experiment and every 14 days to and two experimental units were lost. During the trial three blood samples were taken for evaluation of oxidative and protein parameters. After slaughter, test samples were taken in refrigerated display panel Longissimus dorsi for eight days to study the influence of the oxidative stability in color. There was influence in the final weight, daily gain, carcass weight and Se in the L.dorsi muscle of the treatment with the addition of vitamin E and Se. There was no effect of the plants extract treatment in the blood proteins, indicating healthy animals. The use of plant extracts have antioxidant had effect similar to conventional antioxidants and can be used in the control of oxidative stress.
3

Efeito de extratos de plantas no controle do estresse oxidativo em ovinos confinados alimentados com dieta com elevada proporção de concentrado / Plant extracts effect on the control of oxidative stress in feedlot sheep fed diets with high concentrate

Tiago Ronimar Ferreira Lima 15 August 2016 (has links)
O uso de dietas com elevado teor de concentrado para intensificar a produção de carne de ovinos pode influenciar a homeostase oxidativa do animal, com efeito no seu desempenho e na qualidade da carne. Para buscar meios alternativos, foram testados antioxidantes convencionais em comparação com extratos de plantas no controle do estresse oxidativo em cordeiros alimentados com dieta exclusiva de concentrado. Foram utilizados 48 cordeiros machos Dorper x Santa Inês com peso inicial de 20 ± 1,49 kg desmamados aos 60 dias e alojados em baias individuais e alimentados durante 60 dias com dieta exclusiva de concentrado, composta por 80% milho grão inteiro e 20% pelete proteico, com os tratamentos diferindo apenas na adição dos antioxidantes. Os tratamentos foram controle, sem adição de antioxidante, extrato de plantas com adição de 4 mg/kg de Macleya cordata e Magnolia oficcinalis, tratamento vitamina E e selênio nas quantidades 100UI/kg e 0,1 mg/kg, respectivamente e tratamento extrato de plantas + vitamina E e selênio, nas mesmas quantidades anteriores. A alimentação e a sobra foram pesadas diariamente para determinação de matéria seca e eficiência alimentar. Os animais foram pesados no início do experimento e a cada 14 dias para acompanhamento do desempenho. Foram perdidas duas parcelas experimentais. Durante o período experimental foram realizadas três colheitas de sangue para avaliação de parâmetros oxidativos e proteicos. Após o abate, foram retiradas amostras para análise em painel expositor refrigerado do Longissimus dorsi durante oito dias para influência da estabilidade oxidativa na cor. Houve influência no peso final, ganho diário, peso de carcaça e teor de Se no músculo L.dorsi para tratamentos com adição de vitamina E e Se. Não houve efeito de tratamento para proteínas sanguíneas, indicando que os animais estavam saudáveis durante o experimento. O uso de extrato de plantas teve efeito similar ao dos antioxidantes convencionais e pode ser usada no controle do estresse oxidativo. / The use of high concentrate diets to intensify sheep meat production can influence the oxidative homeostasis of the animal, influencing performance and meat quality. In order to find alternative antioxidants this experiment was carried out to test conventional antioxidants in comparison with plant extracts in the control of oxidative stress in lambs fed exclusively a concentrate diet. Forty-eight male lambs Dorper x Santa Inês with initial weight of 20 ± 1.49 kg weaned at 60 days and housed in individual pens were used. The animals were fed a concentrate diet consisting of 80% whole corn grain and 20% protein pellet, and the treatments differed only in the addition of the antioxidants during 60 days. The treatments were control, no added antioxidant, treatment with plant extract with inclusion of 4 mg / kg plant extract of Macleya cordata and Magnolia oficcinalis, treatment with vitamin E and selenium in amounts of 100 IU / kg and 0.1 mg / kg, respectively, and treatment plant extract + vitamin E and selenium, in the same previous amounts cited. The feed and orts were weighed daily to determine the dry matter intake and feed efficiency. The animals were weighed at the beginning of the experiment and every 14 days to and two experimental units were lost. During the trial three blood samples were taken for evaluation of oxidative and protein parameters. After slaughter, test samples were taken in refrigerated display panel Longissimus dorsi for eight days to study the influence of the oxidative stability in color. There was influence in the final weight, daily gain, carcass weight and Se in the L.dorsi muscle of the treatment with the addition of vitamin E and Se. There was no effect of the plants extract treatment in the blood proteins, indicating healthy animals. The use of plant extracts have antioxidant had effect similar to conventional antioxidants and can be used in the control of oxidative stress.
4

O desvio reprodutivo se correlaciona positivamente com o parentesco genético e o sistema de acasalamento? Euglossa cordata (Hymenoptera, Apidae, Euglossini) como estudo de caso

Freiria, Gabriele Antico 26 June 2015 (has links)
Submitted by Daniele Amaral (daniee_ni@hotmail.com) on 2016-09-14T20:10:01Z No. of bitstreams: 1 TeseGAF.pdf: 2448190 bytes, checksum: 08c41156c28e3e99e6284a8c18acb2d2 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-16T19:49:11Z (GMT) No. of bitstreams: 1 TeseGAF.pdf: 2448190 bytes, checksum: 08c41156c28e3e99e6284a8c18acb2d2 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-16T19:49:17Z (GMT) No. of bitstreams: 1 TeseGAF.pdf: 2448190 bytes, checksum: 08c41156c28e3e99e6284a8c18acb2d2 (MD5) / Made available in DSpace on 2016-09-16T19:49:22Z (GMT). No. of bitstreams: 1 TeseGAF.pdf: 2448190 bytes, checksum: 08c41156c28e3e99e6284a8c18acb2d2 (MD5) Previous issue date: 2015-06-26 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / The orchid bees have always been considered promising for studies of the evolution of social behavior and reproductive division of labor. This is due to the fact that the orchid bees are the only members not clearly eusocial in corbiculate clade. In this study, the correlation between genetic relatedness and reproductive skew was investigated in the genus Euglossa, one of the five genus of Euglossini tribe, in order to support the understanding of the evolution of reproductive division of labor in Euglossini. Among the five genera of Euglossini, Euglossa is the most suitable for studies on the evolution of reproductive division of labor, because in this genus can be found solitary, communal and primitively eusocial species. Twelve nests of Euglossa cordata (Linnaeus, 1758) were analyzed. In this species, the foundation process is solitary, but small colonies are formed during nest reactivations, with females establishing different types of associations, in which their relatedness differs. During reactivations, one of the females performs oophagy and then oviposition in brood cells previously operculated by another females, consequently leaving a larger number of offspring. The behavioral analysis associated with relatedness estimates, made through the use of microsatellite markers, indicated that the dominant female perform oophagy followed by oviposition in all operculated cells by the subordinated bees. The reproductive skew was complete, regardless of the type of association established between the interacting females, and so reproductive skew and genetic relatedness was not associated in this study. Furthermore, the nesting biology of Euglossa was also studied, given the information scarcity about the nesting process in most species already described for this genus. Using the technique of trap nests, 43 nests of Euglossa were sampled. This study provides new information on the nesting biology of this genus, especially with regard to natural enemies associated with nests. / As abelhas da tribo Euglossini sempre foram consideradas promissoras para estudos sobre evolução do comportamento social e divisão de trabalho reprodutivo. Isto decorre do fato dos Euglossini serem os únicos membros não claramente eussociais entre as abelhas corbiculadas. Neste estudo, foi investigada a correlação entre parentesco genético e desvio reprodutivo em uma espécie do gênero Euglossa, um dos cinco gêneros de Euglossini, visando subsidiar o entendimento da evolução da divisão de trabalho reprodutivo na tribo. Dentre os cinco gêneros de Euglossini, Euglossa é o mais indicado para estudos sobre a evolução de divisão de trabalho reprodutivo, pois neste gênero são encontradas espécies solitárias, comunais e primitivamente eussociais. Foram analisados doze ninhos da espécie Euglossa cordata (Linnaeus, 1758). Nesta espécie, o processo de fundação dos ninhos é solitário, mas pequenas colônias são formadas durante as reativações, com as fêmeas estabelecendo diferentes tipos de associações, nas quais o parentesco entre elas é distinto. Durante as reativações, uma das fêmeas realiza oofagias, seguidas de oviposições em células anteriormente operculadas por outras fêmeas, deixando um maior número de descendentes. As análises de comportamento, associadas a estimativas de parentesco, realizadas mediante o uso de marcadores microssatélites, indicam que as fêmeas dominantes realizam oofagia, seguida de oviposição, em todas as células operculadas pelas subordinadas. O desvio reprodutivo foi completo, independentemente do tipo de associação formada entre as fêmeas reativadoras e, portanto, não houve correlação entre parentesco genético e desvio reprodutivo. Além disso, a biologia de nidificação em espécies de Euglossa foi estudada, dada a escassez de informações sobre os hábitos e características do processo de nidificação na maioria das espécies já descritas. Utilizando a técnica de ninhos-armadilha, foram obtidos 44 ninhos de Euglossa. O estudo traz novas informações sobre a biologia de nidificação no gênero, principalmente no que diz respeito aos inimigos naturais associados aos ninhos.
5

Population genetic variation of Mikania species in Taiwan

Tzeng, Guo-Yang 04 August 2003 (has links)
The objective of this study is to elucidate the efficiency of enation-structure (at node) recognition method at pre-flowing stage and to understand the population genetic variation of the Mikania weeds in Taiwan. The plant materials collected by recognizing enation-structure symptom method from North, Central, South and East Taiwan and off-shore islands. Using PCR¡V sequencing marker techniques, the sequencing revealed that nrDNA ITS region could identify three Mikania weeds and the 97% similarity of phylogenetic relationship between M.cordata and M.micrantha are more closer than that between M.cordata and M.scandens, whose ITS sequence is obtained from GeneBank. However ,the sequences of chloroplast DNA of M.cordata and M.micrantha at trnL intron¡]436bp¡^or trnL-trnF IGS¡]345 bp¡^are almost the same and could not be used as molecular markers. The recognizing techniques of enation-structure was supported by the nrDNA ITS region and ISSR results at the end, thus the finding can be recommended to the Council of Agriculture in order to eliminate the weed and to reduce the impact on M.cordata, which is native in Taiwan. Moreover, the findings of ISSR analysis in the aspect of population genetic variation indicated that high genetic differentiation ¡]Gst>0.5¡^was found among the M. cordata and M.micrantha populations. Based on the Mantle test, there was no relationship between genetic distance and geographic distance in M.micrantha¡]r=0.0053,p=0.47¡^.This phenomenon revealed that populations of M.micrantha had complex population variability within the short-term invaded into Taiwan that might be resulted from the random dispersion of human activities. The population of M.micrantha was established by few individuals (founders) and grown rapidly in Taiwan, resulting in population differentiation via genetic drift. In contrast to M.micrantha ,there was relationship between genetic distance and geographic distance in M.cordata ¡]r=0.44,p=0.025¡¯¡^.It revealed that populations of M.cordata agreed to the concept of isolation by distance model, which might be evolved from the result of natural dispersion. In conclusion, the population structure of M.micrantha in Taiwan is stable , suggesting that control of Mikania population should be based on different populations where have large differentiation among them .
6

Host selection and antifeedants in Hylobius abietis pine weevils /

Månsson, Per E, January 2005 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.
7

AN ASSESSMENT OF STREAM QUALITY IN RELATION TO POPULATION HEALTH OF PLANTAGO CORDATA

Hudgens, Faith Victoria 01 September 2021 (has links)
Understanding the health of rare and at-risk plant species is crucial for the conservation of biodiversity. Rare and at-risk species are often specialists with very specific requirements for growth and reproductive success. Some parameters associated with growth and reproductive success of rare aquatic species may include biotic and abiotic factors such as herbivory, competition, water depth, pH, and other factors associated with habitat quality. In this thesis, the population health of the rare and at-risk aquatic species Plantago cordata in Southern Illinois streams is assessed in relation to stream quality of sites containing Plantago cordata and sites without Plantago cordata.The objectives of this study were to (1) Determine if there is a relationship between population size structure and biotic habitat factors among populations and sites, and (2) Determine if there is a relationship between population size structure and abiotic habitat factors among populations and sites. Hypotheses were constructed using the hierarchy-of hypotheses method and most narrow alternative hypotheses are as follows: (1) There will be significant relationships between biotic and abiotic factors and Plantago cordata growth and reproductive success. (2) Levels of herbivory will have significant relationships with growth and reproductive success of Plantago cordata. (3) The abundance of co-occurring species individually and considered in functional groups (graminoid, herb, woody) will have significant relationships with growth and reproductive success of Plantago cordata. (4) Stream depth will have a unimodal relationship with growth and reproductive success of Plantago cordata, with maximum performance at an intermediate stream depth. (5) Stream pH will have a unimodal relationship with growth and reproductive success of Plantago cordata. (6) Stream quality (as outlined by the QHEI assessment) will have significant relationships with growth and reproductive success of Plantago cordata. General trends in herbivory suggest that Plantago cordata could be at greatest risk of herbivory during warmest average temperatures of the study season. There is evidence to suggest that flowering individuals could have a greater threat of herbivory than other growth stages based on Kendal correlation results. A Wilcox test determined that there were no statistical differences in species richness for plots with versus without Plantago cordata. There were relatively low values for percent cover of co-occurring species when considered in functional groups and there was overall relatively low species richness across all communities. Despite this, non-metric multidimensional scaling (NMDS) of community data provided evidence to suggest that there were statistical differences in the species composition of co-occurring individual riparian species among P. cordata populations. A significant negative correlation for water depth and flowering individuals and a significant positive correlation with water depth and pH occurred. A significant positive correlation for stream pH with the numbers of seedlings and dehiscing individuals was also found. One-way analyses of variance (ANOVAs) showed that some populations containing Plantago cordata were found to have stream pH values statistically different from nearby IEPA control streams without Plantago cordata. One population of Plantago cordata was found to be significantly different than two other populations in regards to stream pH using a linear mixed model. A principal components analysis (PCA) of stream Qualitative Habitat Evaluation Index (QHEI) assessments demonstrated distinct clustering of Plantago cordata streams and control IEPA streams without Plantago cordata. These findings provide partial evidence to suggest that growth and reproductive success of Plantago cordata could potentially be impacted by the abiotic and biotic parameters explored in this thesis.
8

Avsättning av sågbara sortiment kopplat till skötsel av svensk sykomorlönn och lind / The connection between sales opportunities of timber and silviculture of Swedish sycamore maple and linden

Nordkvist, Robin, Karlborg, Björn January 2021 (has links)
Marknaden för sågbara sortiment från svenskt lövvirke har haft svårt att fungera på ett tillfredställande sätt, tydligast är problematiken kring de mer udda trädslagen. Råvaran finns i de svenska skogarna och avsättning för råvaran finns i industrin men flödet från skog till industri har tydliga brister. Lösningen har blivit att industrin importerar stor andel av sin lövråvara vilket missgynnar avsättningen av den inhemska råvaran.Studiens främsta syfte var att undersöka avsättningsmöjligheterna för svensk sykomorlönn och lind kopplat till en nulägesbeskrivning av ett tidigare anlagt lövträdsförsök. Resultatet visade att avsättningsmöjligheterna varierade över tid men vid studien var efterfrågan på sykomorlönn svag medan den på lind var stark. Tidpunkten för slutavverkning av de aktuella trädslagen bör således väljas efter när prisbilden är hög.Studien visade att skötseln av de undersökta trädslagen är mycket viktig för att optimera kvaliteten och avsättningsmöjligheterna. De viktigaste parametrarna för god kvalitet var kvist och stamdimension. En större leveransbar volym vid den enskilda avverkningen ökade också avsättningsmöjligheterna. Nyckelord: Acer pseudoplatanus, Tilia cordata, Marknad, Avsättning, Skogsskötsel Keywords: Acer pseudoplatanus, Tilia cordata, Market, Removal, Forest management
9

RESISTANCE TO THREE COMMON HERBICIDES IN CHAMELEON PLANT (HOUTTUYNIA CORDATA THUNB.), A HIGHLY INVASIVE EXOTIC SPECIES

David James Ice (14231480) 03 February 2023 (has links)
<p> Chameleon plant (<em>Houttuynia cordata</em> Thunb.) is native to Southern and Southeastern Asia. It can reproduce sexually through seeds and asexually through rhizomes and is invasive in multiple countries including the U.S. There has been much research on <em>H. cordata</em> as a medicinal species, and its potential as an invasive species is well documented. However, its herbicidal resistance has not previously been quantified. The objective of this study is to assess <em>H. cordata’s </em>resistance to herbicides. This study consisted of two rounds of tests to examine the resistance of <em>H. cordata</em> plants to three commonly used herbicides: SpeedZone, Weed-B-Gon, and Roundup. Two concentrations of each herbicide were used during each trial in the study: the recommended concentration and twice the recommended concentration. Herbicide treatments were applied outside the greenhouse. Herbicides were sprayed uniformly on the plants until the herbicide was dripping off the leaves. The growth of the treated plants was then monitored in the greenhouse. The herbicides generally reduced growth of the plants temporarily. However, plant extermination was not achieved. Plant samples from all herbicidal treatments regrew from rhizomes after all herbicide treatments. Results from the study showed that <em>H. cordata </em>could not be controlled by the recommended concentrations of herbicides commercially available for horticultural uses in the U.S. Doubling the recommended herbicide concentration was also ineffective in exterminating <em>H. cordata </em>plants. This research clearly showed that <em>H. cordata</em> has the potential to become a highly invasive species with the potential to negatively affect the ecological integrity of many communities in the U.S.</p>
10

Spatial variation of photosynthetic capacity of early-, mid-, or late-successional broad-leaved tree species in a temperate mixed forest

Legner, Nicole 23 March 2012 (has links)
No description available.

Page generated in 0.0317 seconds