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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

Molecular systematics of weedy sporobolus species of Australia /

Shrestha, Sangita. January 2001 (has links) (PDF)
Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.
2

The successful life cycle of the pasture weed giant rats tail grass (Sporobolus pyramidalis) /

Bray, Steven Gregory. January 2004 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.
3

Selection of alkali sacaton maternal lineages as competitors with Russian knapweed and Canada thistle

Bartlett, Franklin P. January 2009 (has links)
Thesis (M.S.)--University of Wyoming, 2009. / Title from PDF title page (viewed on May 24, 2010). Includes bibliographical references (p. 50-53).
4

Claviceps purpurea e Bipolaris australis como causa de ergotismo em bovinos no Estado de Santa Catarina / Claviceps purpurea and Bipolaris australis as cause of ergotism in cattle in Santa Catarina State

Hemckmeier, Deise 03 December 2015 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-15T14:34:52Z No. of bitstreams: 1 PGCA15MA209.pdf: 754313 bytes, checksum: d222ad27deddfb1802f4b7162c86c21e (MD5) / Made available in DSpace on 2018-03-15T14:34:52Z (GMT). No. of bitstreams: 1 PGCA15MA209.pdf: 754313 bytes, checksum: d222ad27deddfb1802f4b7162c86c21e (MD5) Previous issue date: 2015-12-03 / FUMDES / Ergotism is a disease caused by ingestion of sclerotia called ergot, which contains alkaloids that act on adrenergic, dopaminergic and serotonergic causing direct effect on blood vessels, smooth muscle and central and autonomic nervous system. The present study describes epidemiological data, clinical signs and lesions of a cattle disease characterized by hyperthermia, tachycardia, tachypnea and injuries in the coronary band of the hoof. Initially cause was attributed to the fungus Claviceps purpurea. Between 2000 and 2014 were reported 13 outbreaks, three distérmica form, three nervous form and seven gangrenous form. However, in five of the seven outbreaks of the gangrenous form, in places where animals grazed there was loads of inflorescences of smut grass (Sporobolus indicus) contaminated by a blackened fungus, classified as Bipolaris australis. The disease was reproduced experimentally by administration of inflorescences of smut grass contaminated by B. australis. For five cattle were administered daily doses of 0.1 g/kg, 0.2 g/kg, 0.2 g/Kg, 0.26 g/kg and 0.34 g/kg for 4, 7, 9, 30 and 30 days respectively. After three to seven days of eating contaminated inflorescences four cattle had diarrhea, tachycardia, tachypnea and intermittent hyperthermia. These clinical signs coincided with warmer days and warmer temperatures of the day. An animal showed hyperemia in the coronary band of the hoof and loss of the tail end of the hair. According to results of this study in cattle, can prove that smut grass (Sporobolus indicus) contaminated by B. australis can cause hyperthermia, tachycardia, tachypnea, injuries in the coronary band of the hoof and loss of the tail end of the hair / Ergotismo é uma enfermidade causada pela ingestão de escleródios chamados de ergot, que contém alcalóides que atuam em receptores adrenérgicos, dopaminérgicos e seratoninérgicos causando efeito direto em vasos sanguíneos, musculatura lisa e sistema nervoso central e autônomo. Descrevem-se dados epidemiológicos, sinais clínicos e lesões de uma enfermidade de bovinos caracterizada por hipertermia, taquicardia, taquipneia e ulcerações na coroa do casco de bovinos. Inicialmente a etiologia foi atribuída ao fungo Claviceps purpurea. Entre 2000 e 2014 foram descritos 13 surtos, três da forma distérmica, três da forma nervosa e sete da forma gangrenosa. Porém, em cinco destes sete surtos, nos locais onde esses animais pastoreavam havia grande quantidade de inflorescências de Sporobolus indicus conhecido como “capim-mourão”, contaminadas por um fungo com coloração enegrecida, identificado como Bipolaris australis. A enfermidade foi reproduzida experimentalmente em cinco bovinos com a administração destas inflorescências. Os bovinos em experimentação receberam respectivamente doses diárias de 0,1g/kg, 0,2g/kg, 0,2g/kg, 0,26g/kg e 0,34g/kg por um período de 4, 7, 9, 30 e 30 dias. Após três a sete dias de ingestão das inflorescências contaminadas, quatro dos cinco animais apresentaram diarreia e manifestaram taquicardia, taquipneia e hipertermia em algum período durante a ingestão. Estes sinais coincidiram com os dias mais quentes deste período. Um animal manifestou hiperemia na coroa do casco e perda de pêlos da extremidade da cauda. Baseado na reprodução experimental é possível afirmar que o capim Sporobolus indicus contaminado pelo fungo Bipolaris australis é capaz de causar hipertermia, taquicardia, taquipneia, hiperemia na coroa do casco e perda de pêlos da extremidade da cauda
5

Native plant population resilience to exotic invasion

Mealor, Brian A. January 2006 (has links)
Thesis (Ph. D.)--University of Wyoming, 2006. / Title from PDF title page (viewed on April 16, 2008). Includes bibliographical references.
6

Traitement des boues de vidange par lits de séchage sous climat soudano-sahélien / Treatment of faecal sludge on planted and unplanted bed in soudano-sahelian climate

Kouawa, Tadjouwa 13 July 2016 (has links)
L'usage des lits de séchage plantés et non plantés (LSP et LSNP) pour le traitement des boues de vidange (BV) augmente en Afrique de l’Ouest malgré leurs performances parfois mauvaises et leur dimensionnement empirique. Pour contribuer à I'accès aux performances épuratoires des LSP et LSNP, le suivi de 13 lits de séchage expérimentaux a été réalisé. Sur la base de l'équation de consolidation de Terzaghi, un modèle, permettant de simuler I'humidité volumique des boues sur les lits, a été développé selon 2 approches. Les résultats montrent des performances épuratoires mitigées. Pour des valeurs seuils de concentrations de BV, les 3 espèces testées sur les LSP ont flétries. Les simulations avec l’Approche 1 présente des erreurs absolues relatives inférieures à 15% et sont meilleures que ceux avec l'approche 2. Cependant, I'approche 2 a l'avantage de reproduire les tendances de l'évolution des coefficients de consolidation et perméabilité des boues en fonction de la profondeur et du temps. / Despite the bad performances sometimes obtained according to the context and the empirical method of design, the use of drying beds (planted and not planted) for the treatment of faecal sludge (FS) increase in West Africa. To access to treatment performances in local context (Ouagadougou), the monitoring of 13 experimental drying beds were done. Based on the Terzaghi consolidation equation, the development of a numerical model were done according 2 approaches. Regarding removal efficiency, the performances of treatment of sludge on drying beds were mitigated. The results demonstrate that Oryza longistaminata, Sporobolus pyramidalis and Cyperus alopecuroïdes cannot be used in sludge drying planted beds for the treatment of FS. The simulations with the model in the approach 1 were better than those in approach 2. However, the approach 2 can reproduce the trends of volumetric moisture, the trends of consolidation coefficient and permeability as a function of depth and as a function of time.
7

Optimisation des marais filtrants pour l’abattement du pesticide chlorantraniliprole du ruissellement agricole

Abas, Khalil 02 1900 (has links)
Au cours des dernières décennies, une grande variété de pesticides émergents, tels que le chlorantraniliprole (CAP), ont été introduits malgré le manque de connaissance approfondie de leur risque écotoxicologique. Les marais filtrants (TW) sont des technologies écologiques et durables qui ont montré un grand potentiel d’atténuation des polluants agricoles communs, tels que les pesticides dans le ruissellement. L’objectif de cette étude était d’optimiser l’utilisation du marais filtrant sous-surfacique à écoulement horizontal (HSSF) en déterminant: a) l'effet d’un amendement de biochar au substrat et b) la performance de trois espèces de macrophytes (Phragmites australis subsp. americanus, Scirpus cyperinus et Sporobolus michauxianus) dans l'abattement du CAP du ruissellement agricole. L'efficacité d'abattement a été calculée en utilisant la méthode du bilan de masse dans des mésocosmes HSSF matures alimentés avec un ruissellement agricole synthétique contenant du CAP pendant une période d'un mois. Les mésocosmes avec l’ajout de biochar se sont avérés très efficaces dans l’abattement du CAP (90 à 99%) et ils le sont restés tout au long de la période expérimentale. Cette efficacité est probablement due à la grande capacité d’adsorption du biochar, bien que ce mécanisme n’ait pas été directement mesuré. En revanche, l'abattement du CAP dans les mésocosmes plantés sans biochar était faible et limité et il n’y avait pas de différence entre les espèces, bien qu’elles aient eu des différences dans leur biomasse aérienne et leur taux d'évapotranspiration (ET). Cependant, les traitements plantés ont agi comme zone tampon, en atténuant la masse du CAP de l'influent et en la libérant lentement dans l'effluent. Le taux d'ET de Scirpus et Phragmites était plus élevé que celui de Sporobolus, ce qui s’est traduit par un meilleur effet tampon. Cette étude suggère que l'ajout de biochar au substrat HSSF TW est prometteur pour l'atténuation du CAP dans le ruissellement agricole, mais leur efficacité à long terme reste à être étudiée. Malgré tout, les TW devraient être utilisés comme un outil complémentaire, dans le cadre d'actions plus larges visant à réduire la pression des polluants sur les écosystèmes aquatiques. / Over the past decades, a wide variety of emergent pesticides, such as chlorantraniliprole (CAP), have been introduced despite the lack of in-depth knowledge of their ecotoxicological risk. Treatment wetlands (TWs) are environmentally friendly and sustainable technologies that have shown great potential to mitigate common agricultural pollutants, such as pesticides in runoff. The objective of this study was to optimize the use of the horizontal subsurface flow treatment wetlands (HSSF TWs) by determining a) the effect of biochar amendment to the substrate and b) the performance of three species of macrophytes (Phragmites australis subsp. americanus, Scirpus cyperinus and Sporobolus michauxianus) in CAP removal from agricultural runoff. The removal efficiency was calculated using the mass balance method in mature HSSF mesocosms fed with synthetic agricultural runoff containing CAP for a period of one month. Mesocosms with the addition of biochar were very effective in removing CAP (90-99%) and remained so throughout the experimental period. This efficiency is likely due to the high adsorption capacity of biochar, although this mechanism has not been directly measured. In contrast, CAP removal in mesocosms planted without biochar was low and limited and there was no difference between species, although there were differences in their above-ground biomass and their evapotranspiration (ET) rate. However, the planted mesocosms acted as buffer zones, reducing the CAP mass of the influent and slowly releasing it into the discharge. The ET rate of S. cyperinus and P. australis was higher than that of S. michauxianus, resulting in a better buffering effect. This study suggests that adding biochar to the HSSF TW substrate is promising for CAP attenuation in agricultural runoff, but their long-term effectiveness remains to be investigated. Nevertheless, TWs should be used as a complementary tool, as part of wider actions aimed at reducing the pressure of pollutants on aquatic ecosystems.
8

An investigation of seasonal disturbance intensity on wetland grass belts of Nysvley Nature Reserve

Gelebe, Vhuhwavho 17 May 2019 (has links)
MSc (Botany) / Department of Botany / The use of disturbance in the management of Savanna is a common rangeland practice in South Africa. A two-season trial was established in June 2016 and December 2016 to evaluate the effects of disturbance of different intensities on wetland belts in the Nylsvley Nature Reserve. The disturbances were in three different belts of different grass types at different intensities. The experimental treatments consisted of two different intensities, namely; high (H) and low (L). The Cyperus amabilis belt was regarded as site 1, the Sporobolus africanus as site 2, and the Themeda triandra as site 3. Seventeen kites were contracted in each belt, two times 1 m × 1 m at high and low intensity, followed by two times 2 m × 2 m one at high intensity. The results showed that disturbance affects the topsoil by removing the soil which is rich in nutrients producing pioneer species for the first few months and then original species were seen inhibiting again. / NRF

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