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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.
171

Biologická aktivita sekundárních metabolitů rostlin X. Alkaloidy Vinca minor L. / Biological aktivity of secondary plants metabolites X. Alkaloids of Vinca minor L.

Šípková, Pavla January 2019 (has links)
Šípková, P.: Biological activity of secondary plants metabolites X. Alkaloids of Vinca minor L. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové, 2019, 66 s. Key words: Apocynaceae, Vinca minor, alkaloids, isolation, biological activity, screening Alzheimer's disease is a progressive neurodegenerative disease. The number of affected patients is constantly increasing. This disease cannot be treated casually, therefore discovering and testing new substances that could potentially be used in a treatment is very important. The Vinca minor L. fraction after column chromatography was separated by flash chromatography. Isolation of the individual alkaloids was performed by preparative TLC. Based on NMR and MS analyses and comparison with literature, alkaloids were identified as vincarubine and (-)-vinoxine. Modified Ellman's method was used to test cholinesterase inhibitory activity of isolated alkaloids. Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) are enzymes, that play a very important role in the pathofysiology of Alzheimer's diasease. (-)-Vinoxine showed relatively high activity against BuChE (IC50 = 24,61 ± 1,71 µM), inhibitory activity against AChE was insignificant (IC50 > 1000µM). Vincarubin did not...
172

Pressure Loss Coefficients for Large Mitered Elbows with Diameters Ranging from 36-inches to 144-inches

Coombs, Hayden J. 01 May 2019 (has links)
When designing a pipeline system, it is important to understand the pressure losses that will occur within the system. One common source of pressure loss is from elbow pipe fittings. There is extensive research available for pressure loss coefficients of elbow pipe fittings, but the research is derived from elbows with relatively smaller pipe diameters. The purpose of this research is to investigate pressure losses associated with larger diameter mitered elbows (36-inches to 144-inches). The dimensions for all mitered elbows considered in this research follow ANSI/AWWA C208-17 recommendations (AWWA 2017). Due to the large size of the mitered elbows of interest, physical testing was not feasible for this research. Therefore, this research used numerical methods to determine the pressure loss coefficients of large mitered elbows, reducing mitered elbows, and expanding mitered elbows. The results suggest a strong correlation that the pressure loss for large mitered elbows, presented in this research, are solely dependent on the pipe Reynolds number. The reducing and expanding mitered elbows showed the pressure loss coefficient is dependent on Reynolds number and the percent of reduction/expansion of the elbow. Tabulated data, graphical data, and recommended equations are presented to determine pressure loss for large mitered elbows, reducing mitered elbows, and expanding elbows.
173

The marine and terrestrial ecology of a northern population of the Little Penguin, Eudyptula minor, from Bowen Island, Jervis Bay

Fortescue, Martin, n/a January 1998 (has links)
The breeding success of the Little Penguin was significantly higher in northern populations compared with documented southern colonies. Several southern colonies including Phillip Island in Victoria and colonies in Tasmania, have been characterised by poor breeding success, increasingly later commencement of breeding, and declining populations. This study aimed to compare and contrast the ecological attributes of a thriving northern population with other documented colonies. I collected long term data on breeding success (1987 to 1997) of the Little Penguin on Bowen Island, and related variability in breeding success to ocean currents and climate patterns, foraging behaviour and diet, nesting habitat, and inter-specific and fisheries competition. The benefits of successional changes to nesting habitat on Bowen Island since active habitat management commenced in 1989 were examined, including the importance of burrow depth, aspect, distance to water from the burrow, and vegetation type on breeding success of the Little Penguin. Morphological measurements of east coast penguins indicated a north-south cline, similar to that described in New Zealand. The Little Penguin was larger at higher latitudes. Whilst adults were sedentary and displayed a high degree of nest site fidelity, juveniles dispersed widely in their first three years, but then returned to the colony, sometimes to their natal burrow, to breed. This appears to be an adaptive mechanism, which selects for high quality nesting habitat. The study confirmed earlier findings that mature vegetation assemblages, namely woodland and forest, support higher breeding success than structurally simpler grassland and herbland habitat. This may contribute to observed differences in breeding success between northern and southern colonies, because many of the southern colonies have degraded nesting habitat. Most important to the diet of the Little Penguin were clupeoids, which dominated the fish species of Jervis Bay. The substantial clupeoid resources were targeted by the tuna fishery for bait, in the same areas and coinciding with maximum demands (chick raising and fledging), as penguins. The potential quantity of baitfish taken from Jervis Bay was over 10, 000 tonnes per year, which was well beyond the quantities raising concerns in other regions, although the fishery remains unregulated. Nevertheless, the foraging range of Bowen Island penguins was smaller than has previously been described Little Penguins on Bowen Island had a heavy reliance on relatively shallow waters of the Bay, within 5 km of the island. Daily foraging distances exceeding 20 km coincided with low breeding success, sometimes below that required for population replacement. Greater daily foraging range during the breeding season in southern Victoria may explain in part why these populations are declining. The principal mechanism for nutrient enrichment of Jervis Bay waters was the East Australia Current (EAC). This is a large and powerful, warm water boundary current of 250 km diameter and 1000 feet depth, which promoted slope water intrusion through upwelling along the New South Wales coast during the study, particularly during the penguin breeding season. The EAC effects northern colonies, but less so southern colonies. The Bowen Island colony was prone to periodic breeding failure, which was related to the El Nino Southern Oscillation (ENSO) phenomenon, indicated in Australia by the Southern Oscillation Index (SOI). ENSO warm events, corresponding with negative values of the SOI, depressed the EAC and caused downwelling, leading in some seasons to increased breeding failure. There was a correlation between both fledging success and adult mortality, and the SOI. The mean breeding success of the Bowen Island colony, at 1.46 chicks per pair over the ten-year study, was the highest recorded for the Little Penguin, and the population was increasing.
174

Gambians don’t like maths? : A Minor Field study on how mathematics is taught in a primary school in the Gambia / Matematikundervisning i de yngre åldrarna i en skola Gambia – hur går den till?

Borén, Jenny January 2010 (has links)
<p>In this text about the mathematics education in a primary school in the Gambia, I am researching what this mathematics education consists of and what surrounding factors might be affecting it. The pupils of the school in question speak several different languages. This language situation is one of the factors considered in the research. A connection between the real life led by the pupils and their mathematics education was a second factor. The third factor is financial resources or the lack thereof. I wanted to see if a lack of sufficient financial resources was visible in forming the education and the teaching of the pupils. The teaching of mathematics in the school seemed to be based on behaviourism, but could perhaps take benefit from the ethnomathematics perspective. Through observations, analyzing documents and an interview, I realized that the government had set ambitious objectives for the teachers to follow, but due to lack of economical resources, as far as my study found, these are not achieved. As ambitious objectives, which are not followed by sufficient funding is an issue not only applicable in Gambian schools and since Sweden is a growing multicultural society, I can use my knowledge from this study in my work in Swedish schools.</p> / MFS - Minor Field Studies
175

Political representation in KwaZulu-Natal, South Africa

Larsson Falasca, Kajsa January 2008 (has links)
<p>This is a Minor Field Study (MFS) which is a scholarship financed by the Swedish International Development Cooperation Agency (SIDA). It was conducted in the province of KwaZulu-Natal in South Africa in 2007/2008. The purpose of this study is to understand the role of the political representative in the system of political representation and it will test the different theories of political representation based on interests or identity. This study is concerned with the function of the political representatives as they are the link between the system of representation and the electorate. Since the election system is designed for political representation based on interest and the voting in South Africa suggests voting based on identity/race the representatives must balance these different signals.</p>
176

Automatic landmark detection on Trochanter Minor in x-ray images / Automatisk landmärkesdetektering på Trochanter Minor i röntgenbilder

Holm, Per January 2005 (has links)
<p>During pre-operative planning for hip replacement, the choice of prosthesis can be aided by measurements in x-ray images of the hip. Some measurements can be done automatically but this require robust and precise image processing algorithms which can detect anatomical features. The Trochanter minor is an important landmark on the femoral shaft. In this thesis, three di.erent image processing algorithms are explained and tested for automatic landmark detection on Trochanter minor. The algorithms handled are Active Shape Models, Shortest path algorithm and a segmentation technique based on cumulated cost maps. The results indicate that cumulated cost maps are an e.ective tool for rough segmentation of the Trochanter Minor. A snake algorithm was then applied which could .nd the edge of the Trochanter minor in all images used in the test. The edge can be used to locate a curvature extremum which can be used as a landmark point.</p>
177

Leachate treatment and anaerobic digestion using aquatic plants and algae

Ström, Emma January 2010 (has links)
<p>Phytoremediation as a way to control and lessen nutrient concentrations in landfill leachate is a cheap and environmentally sustainable method. Accumulated nutrients in the plants can then be removed by harvesting and anaerobically digesting the biomass. This study presents two aquatic plants (L. minor (L.) and P. stratiotes (L.)) and one microalgae species (C. vulgaris (L.)), their capacities for growth and nutrient removal in leachate from Häradsudden landfill, Sweden, are investigated. The biogas potential of the two plants is determined via anaerobic digestion in a batch run, followed by a lab-scale reactor run for L. minor only. Results show that growth in leachate directly from the landfill is not possible for the selected species, but at a leachate dilution of 50% or more. Nutrients are removed in leachates with plants to a higher extent than in leachates without, yet the actual amounts do not differ notably between plant species. L. minor proves a better choice than P. stratiotes despite this as growth is superior for L. minor under the experimental conditions of this study. Considering biogas production, L. minor gives more methane than P. stratiotes according to the results from the batch run. The former is however not suitable for large-scale anaerobic digestion unless as an additional feedstock due to practical cultivation issues.</p>
178

Parents' Impressions of Their Child's Minor Surgical Procedure with Nitrous Oxide

Shapiro-Stoler, Tina J. 16 December 2009 (has links)
Invasive procedures are often painful and distressing for children and disturbing for their parents. The purpose of this study was to develop a substantive theory of parental perceptions of their school-aged child's responses to an outpatient minor surgical procedure with nitrous oxide. The sample included 22 parents of 21 children who underwent a nitrous procedure. Participants were recruited from the pediatric surgery department at a children's hospital. Semi-structured, audio-recorded interviews were conducted with each participant. Grounded theory method was used to simultaneously collect and analyze the data using the constant comparative method. The findings of the study revealed parental impressions involving a process of various emotions and behaviors. The identified process began at procedural scheduling, progressing through the procedure, and terminated going home. The core category derived from the data was Weathering the Storm before the Calm by Securing Connections. This core category describes the complexity of parental impressions and all categories subsumed by the core category. Six major categories and seven subcategories derived from the data represent parental impressions. Parental feelings of anxiety and fear arose during initial phases of the process. Parents attempted to deal with these stormy feelings in several ways. Parents experienced a sense of calmness after the procedure upon realizing their child was safe. The theme that weaves through the entire process is the parental-child connection and parental presence during the nitrous procedure. Parents also identified barriers and facilitators they faced during this process. The substantive theory that emerged provides nurses with an understanding of the stormy and subsequent calm phases parents endured. This information offers clinicians unique interventions to help parents get through this process. Future research needs extension to other settings such as radiology and other specialties such as plastic surgery and urology. Further research warrants investigating children's perceptions to their procedure with nitrous oxide.
179

Gambians don’t like maths? : A Minor Field study on how mathematics is taught in a primary school in the Gambia / Matematikundervisning i de yngre åldrarna i en skola Gambia – hur går den till?

Borén, Jenny January 2010 (has links)
In this text about the mathematics education in a primary school in the Gambia, I am researching what this mathematics education consists of and what surrounding factors might be affecting it. The pupils of the school in question speak several different languages. This language situation is one of the factors considered in the research. A connection between the real life led by the pupils and their mathematics education was a second factor. The third factor is financial resources or the lack thereof. I wanted to see if a lack of sufficient financial resources was visible in forming the education and the teaching of the pupils. The teaching of mathematics in the school seemed to be based on behaviourism, but could perhaps take benefit from the ethnomathematics perspective. Through observations, analyzing documents and an interview, I realized that the government had set ambitious objectives for the teachers to follow, but due to lack of economical resources, as far as my study found, these are not achieved. As ambitious objectives, which are not followed by sufficient funding is an issue not only applicable in Gambian schools and since Sweden is a growing multicultural society, I can use my knowledge from this study in my work in Swedish schools. / MFS - Minor Field Studies
180

Minor-minimal non-projective planar graphs with an internal 3-separation

Asadi Shahmirzadi, Arash 13 November 2012 (has links)
The property that a graph has an embedding in the projective plane is closed under taking minors. Thus by the well known Graph Minor theorem of Robertson and Seymour, there exists a finite list of minor-minimal graphs, call it L, such that a given graph G is projective planar if and only if G does not contain any graph isomorphic to a member of L as a minor. Glover, Huneke and Wang found 35 graphs in L, and Archdeacon proved that those are all the members of L, but Archdeacon's proof never appeared in any refereed journal. In this thesis we develop a modern approach and technique for finding the list L, independent of previous work. Our approach is based on conditioning on the connectivity of a member of L. Assume G is a member of L. If G is not 3-connected then the structure of G is well understood. In the case that G is 3-connected, the problem breaks down into two main cases, either G has an internal separation of order three or G is internally 4-connected. In this thesis we find the set of all 3-connected minor minimal non-projective planar graphs with an internal 3-separation. For proving our main result, we use a technique which can be considered as a variation and generalization of the method that Robertson, Seymour and Thomas used for non-planar extension of planar graphs. Using this technique, besides our main result, we also classify the set of minor minimal obstructions for a-, ac-, abc-planarity for rooted graphs. (A rooted graph (G,a,b,c) is a-planar if there exists a split of the vertex a to a' and a' in G such that the new graph G' obtained by the split has an embedding in a disk such that the vertices a', b, a', c are on the boundary of the disk in the order listed. We define b- and c-planarity analogously. We say that the rooted graph (G,a,b,c) is ab-planar if it is a-planar or b-planar, and we define abc-planarity analogously.)

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