• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 22
  • 8
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 44
  • 28
  • 22
  • 12
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 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.
41

Charakterizace společenstva hub, podílejícího se na rozkladu opadu v jehličnatých lesích Národního parku Šumava / Charakterizace společenstva hub, podílejícího se na rozkladu opadu v jehličnatých lesích Národního parku Šumava

Žifčáková, Lucia January 2012 (has links)
Understanding of carbon cycling in coniferous forests that represent a large carbon sink is crucial for our understanding of natural processes under global climate change. Recognition of fungi as fundamental decomposers can contribute to this understanding. Fungi are able to decompose numbers of substrates and possess a variety of enzymes to do so In this study I present litter decomposing fungi in mountain spruce forest from national park Šumava. The aim of my thesis was to follow succession and community changes of fungi from the early stages of decomposition of Picea abies needles until degradation of organic matter in the organic horizon of the soil. This aim was accomplished partly by recording the extracellular enzyme production of fungi in different stages of decomposition from needles attached to the twigs of a fallen tree to a litter material in later stages of decomposition on the soil surface. In addition to testing of fungi on their natural substrata - needle litter, enzyme activities were also measured in laboratory agar cultures, which allow comparison of diverse fungi with different origins. Enzyme activities were aimed at enzymes decomposing cellulose and compounds found in litter. Although ecology of endophytic and saprothrophic fungi suggest differences in enzyme production, these...
42

Host-parasite coevolution in New Zealand: how has Odontacarus, a mite with a free-living stage in its life-cycle, coevolved with its skink host?

Vargas, Mariana L. January 2006 (has links)
The effect of a free-living stage in host-parasite coevolution: a skink mite phylogenetic study in New Zealand. During the last decade, phylogenetic trees have even been used to compare ecologically related taxa such as parasites and their hosts, and are used to determine their level of coevolution or reciprocal adaptation in time. Diverse coevolutionary events have been detected for this ecological association, where generally the parasite has been regarded as one that feeds exclusively on the host and is likely to cospeciate with it. A different coevolutionary pattern might occur when the parasite has a free-living stage in its life cycle, in which the parasite may have the opportunity to abandon its host and successfully colonise a new species (host-switching) making cospeciation less likely. Many New Zealand skinks are infested with a parasitic mite, Odontacarus sp. (Prostigmata: Leeuwenhoekiidae), which becomes free-living as an adult. The genetic variation of these mites found on four hosts was analyzed for host- parasite coevolutionary events. The hosts were the McCann’s skink and the common skink in coastal Birdling Flat, Canterbury, plus these species and the Grand and Otago skinks in Macraes Flat, Central Otago, South Island, New Zealand. The genetic variation of fast evolving nuclear Internal Transcribed Spacers 2 and mitochondrial Cytochrome c Oxidase I in Odontacarus mites found on these hosts was determined by PCR and DNA sequencing and phylogenetic trees were built using the computer programs PAUP*4 and MrBayes 3. The results show that mite haplotypes only had a significant geographical division and no host-related differences. In Birdling Flat, the COI haplotypes were represented in two groups that infested both regional hosts and had 5.7 % divergence. The same individual mites belonged to a single ITS 2 haplotype, thus indicating a historical geographical division between two populations that now interbreed successfully. The Macraes Flat mites were divided into two COI haplotypes with 2.4% divergence and internal nodes, which showed greater genetic variability than the Birdling Flat populations. The Macraes Flat mites formed two ITS 2 haplotypes with 6% divergence. This greater geographical structure of the Otago mites is probably due to the older age of the mainland area compared to the recently exposed coastal locality of Birdling Flat. The COI haplotypes from the two different regions had a mean distance of 15.5%, with an earlier divergence time than that known for the hosts. For both genes, the haplotypes from different regions had 100% bootstrap support and the parasite showed no host specificity. Mites of the different COI and ITS haplotypes were found on most of the host species that were sampled in Canterbury and Otago. The results of this study suggest that a free-living stage in a parasite’s life cycle can favour coevolutionary events such as inertia (failure to speciate) and host-switching, probably as a result of resource-tracking of the parasite. NB: Electronic files contained on CD to accompany print copy are not included with this version of the thesis.
43

TEACHER SUPPORTS USING THE FACILITATOR MODEL FOR DUAL CREDIT IN OPEN ENDED DESIGN THINKING COURSEWORK: UNIVERSITY COLLABORATION AND HIGH SCHOOL IMPLEMENTATION

Scott Tecumseh Thorne (10730865) 30 April 2021 (has links)
The facilitator model for dual credit offers a way for student to earn directly transcripted credit to colleges and universities, overcoming many barriers faced by other dual credit models. Successful implementation of this model requires high degree of involvement from the cooperating institution. This IRB approved qualitative case study explored the needs of five teacher facilitators in both summer professional development and on-going support throughout the school year when implementing a facilitator model for dual credit with open-ended design coursework. Code-recode and axial coding techniques were applied to over 90 hours of transcribed data, artifacts, and observations from a seven month period to find emerging themes and offer recommendations for implementation.<p></p>
44

Organisation, practice and experiences of mouth hygiene in stroke unit care: a mixed methods study

Horne, Maria, McCracken, G., Walls, A., Tyrrell, P.J., Smith, C.J. 03 1900 (has links)
No / Aims and objectives To (1) investigate the organisation, provision and practice of oral care in typical UK stroke units; (2) explore stroke survivors', carers' and healthcare professionals' experiences and perceptions about the barriers and facilitators to receiving and undertaking oral care in stroke units. Cerebrovascular disease and oral health are major global health concerns. Little is known about the provision, challenges and practice of oral care in the stroke unit setting, and there are currently no evidence-based practice guidelines. Design Cross-sectional survey of 11 stroke units across Greater Manchester and descriptive qualitative study using focus groups and semi-structured interviews. Methods A self-report questionnaire was used to survey 11 stroke units in Greater Manchester. Data were then collected through two focus groups (n = 10) with healthcare professionals and five semi-structured interviews with stroke survivors and carers. Focus group and interview data were recorded, transcribed verbatim and analysed using framework approach. Results Eleven stroke units in Greater Manchester responded to the survey. Stroke survivors and carers identified a lack of oral care practice and enablement by healthcare professionals. Healthcare professionals identified a lack of formal training to conduct oral care for stroke patients, inconsistency in the delivery of oral care and no set protocols or use of formal oral assessment tools. Conclusion Oral care post-stroke could be improved by increasing healthcare professionals' awareness, understanding and knowledge of the potential health benefits of oral care post-stroke. Further research is required to develop and evaluate the provision of oral care in stroke care to inform evidence-based education and practice.

Page generated in 0.0598 seconds