• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 468
  • 424
  • 180
  • 176
  • 77
  • 13
  • 9
  • 8
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 1773
  • 535
  • 260
  • 216
  • 213
  • 213
  • 184
  • 145
  • 135
  • 134
  • 127
  • 127
  • 113
  • 108
  • 105
  • 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.

Investigating the current state of the art on Ethics Reviews of Information and Communications Technology Research in UK Universities

Eke, Damian January 2012 (has links)
Information and Communications Technology (ICT) is a concept that represents the convergence of some defining technologies of our time (information technology, computer technology and media technology) and the increasing influences its research and usage have on the society today. With such distinctive features as pervasiveness, ubiquity, malleability, interactivity, augmentation, autonomy and virtualization, ICT research and usage provide an array of ethical and social challenges. However, most contemporary research on ICT ethics concentrates only either on the usage of ICT artefacts or on questions that raise significant theoretical or practical interest such as ICT implants or eHealth. There has been little research on the ethical and social issues associated with research and development. This research draws attention back to the beginning- research and development. It seeks to find out how ethical issues are considered in ICT research being carried out in the UK computing departments/faculties. It investigates the current state of the art with regard to ethics reviews of ICT research through establishing its relevance, availability and effectiveness. The fact that high quality researches (including European projects) in ICT are currently being carried out in so many UK computing departments, which also produce engineers for IT companies, justifies the choice of the UK in this research. Even though a quantitative tool of questionnaire was used as part of the data collection methods, the interpretive and subjective nature of this research find reference in the use of interviews for the main data collection and dialectical hermeneutics for data analysis. Through a dialectical hermeneutic process, the different understandings on availability, relevance and effectiveness of ethics reviews of ICT research emerged. These understandings showed the strengths and weaknesses of the current ethics review procedures in the UK computing departments which provided the basis for relevant recommendations to policy makers.

An investigation into the influence of learning styles and other factors affecting students' perception of virtual learning environments

Swesi, Khaled January 2012 (has links)
In order to explain and determine the attitudes and factors affecting perceptions of students to adopt and use Virtual Learning Environment (VLE) as a tool in complementing and supplementing face-to-face learning, this research combined two theoretical models: Technology Acceptance Model (TAM), one of the more popular acceptance models, and Learning Style Inventory (LSI). The Technology Acceptance Model is one of the models used to study the problem of low adoption or underutilization of technology while learning styles model adopted in order to determines the preferred learning styles for the users of VLE. This study investigates students at Tripoli University, the main University in Libya to understand their perceptions of using VLE with respect to their learning styles. The study used a quantitative descriptive research design method by using a survey as the primary means of data collection. Empirical data were collected from different departments and schools (n=302) to examine the impact of specialisation construct. The study proposed a conceptual model which includes external variables derived from previous research, the core TAM model combined with learning style as an independent variable in order to determine the impact of learning styles on the perception of students towards VLE use. A combination of t tests, ANOVAs, chi-squares, and Pearson’s product-moment correlation coefficients was used to analyse the data by using two techniques: single and multiple regressions. Findings from the quantitative data revealed that, regardless of gender or learning styles impacts, the participants have a strong positive behavioural intention to use VLE tools in their existing learning environment. The results of this study implied that gender and learning styles did not play a significant role in determining perceptions and usage of VLE. However, the other defined independent variables had significant effects on the model and contributed to the explanation of the model except for example, job relevance, complexity factors. The interesting result found in this study was the fact that the specialisation constructs shows that there is a different level of VLE use depending on the student’s specialisation, namely that natural and formal science students showed the most interest in using the new technology. Another interesting outcome found that students’ perceived ease of use demonstrated a more consistent influence compared to usefulness in determining the usage of VLE. This finding is new and is inconsistent with most previous research. Although, the results show that there is no significant impact of learning styles on the research model, the results, however, show learning styles can play a very important role as a moderating factor between beliefs constructs and external variables. The results of the coefficients were not the same for each learning style, which may indicate that different learning styles moderate the relationships between variables involved in the research model (VLEAM). The people with the highest coefficients were those with the assimilator style compared to other learning styles, followed by divergent/accommodator convergers. This means that assimilators are the best target learners for VLE. However, the results show that female assimilators have more negative impact on PU, meaning that they regard VLE as being less useful. The parameters in the model may be altered for each learning style to get the maximum benefit from the model. From a theoretical and methodological perspective, it was found that TAM being a simple psychological model was not good enough to explain broader systems such as VLE and subsequently has not fully explained students’ perceptions towards use. In the light of the findings, the study suggested that a study of adoption and acceptance technology should move from using a simple psychological TAM model to another form that is able to measure IS that contains complex functions. The outcomes of the study are beneficial to decision makers at the university level when making decisions about technologies that affect the teaching and learning process as well as assisting in institutional decision in regards to where to commit resources (technology, monetary, labour, etc.) to implement and maintain those systems.

Ecosystem service provision in dynamic heath landscapes

Cordingley, Justine E. January 2012 (has links)
Conservation policy and management is undergoing a step-change, moving from focusing conservation resources on individual sites such as protected areas, to include the wider landscape. Landscape-scale initiatives may focus on either managing the entire landscape or they may focus on managing particular sites but attempt to address landscape-scale patterns and processes, such as habitat fragmentation. Whilst there is a vast body of research investigating the impacts of habitat fragmentation on individual species, much less is known about the impacts of habitat fragmentation on ecological processes, for example woody succession. Woody succession is an ecological process which has particular implications for conservation management as it drives ecosystem dynamics which can alter the value of the habitat for species of conservation concern. At the same time there is a move to incorporate ecosystem service protection into conservation policy. Understanding the synergies and trade-offs that exist between biodiversity conservation and ecosystem service provision is therefore an important priority. Few studies have examined the influence of habitat fragmentation on woody succession and, in turn, the impact of woody succession on the value of the habitat for both biodiversity conservation and ecosystem service provision. In addition, there is still very little evidence suggesting to what extent areas managed for biodiversity conservation also provide ecosystem services. There is a need to understand how management approaches aimed at increasing the biodiversity value of conservation areas will impact ecosystem services, particularly at the level of the landscape. This thesis aimed to explore all these themes in the Dorset lowland heathlands, UK. The Dorset lowland heathlands are highly fragmented and a priority habitat for nature conservation because they are rare and threatened and support a characteristic flora and fauna. The main threat to this habitat is now woody succession. Without conservation management, the characteristic dwarf shrub heath undergoes succession and is replaced by scrub and woodland. The objectives of this thesis were to (1) assess the impact of fragmentation on the process of succession on lowland heathlands and quantify lowland heathland vegetation dynamics; (2) determine biodiversity and ecosystem service values of major cover types along a successional gradient on lowland heathlands and assess how trade-offs and synergies between biodiversity and ecosystem service provision vary along this gradient and (3) explore how alternative management approaches aimed at increasing the biodiversity value of lowland heathlands impact ecosystem service provision. Fragmentation was found to promote succession with smaller heaths undergoing succession faster than larger heaths. Trade-offs were found between biodiversity value and ecosystem service provision. Biodiversity value was highest in heath habitats and lowest in woodland. Carbon storage, aesthetic value and timber value were highest in woodland. However, recreation value was associated with heathland habitats and not woodland. Conservation management for biodiversity increased the biodiversity value of lowland heaths but not the provision of ecosystem services.

Behavioural causes and consequences of sexual size dimorphism in an apex predator species

Nyqvist, Marina J. January 2012 (has links)
Individual differences within populations in a range of phenotypic traits are hypothesised to have important ecological and evolutionary implications. Variation in individual growth rates that result in corresponding variations in body sizes, including size dimorphism, is a particularly widespread feature of many animal populations. The increasing characterisation of consistent individual behavioural variations, unrelated to age or sex, is equally considered to have important fitness consequences. Our understanding of behavioural causes of size dimorphism remains weak, and few studies have investigated the relationship between individual behavioural consistency and growth variations in size dimorphic populations. The overall aim of this thesis is to identify the behavioural drivers that underpin observed growth variations and result in size dimorphism by using pike (Esox lucius) as a model species. The results show that early life growth is an important driver of sexual size dimorphism in this species. A subsequent focus on the juvenile life stages revealed that individual differences in movement and dispersal tendencies were related to growth and body size in wild pike. The findings indicate that intraspecific interactions such as size-dependent interference competition during the first year of life plays a key role in maintaining intraspecific size variation and size dimorphism in the wild population. Experimental work revealed the occurrence of a behavioural syndrome, where the rank order differences in the foraging behaviour between individuals were maintained across time and risk situation. This suggests that individual competitive ability is underpinned by a variation in boldness to forage under risk. The importance of a heterogeneous environment and presence of intraspecific competition pressure for driving habitat and resource segregation, and subsequently sexual size dimorphism, is discussed.

Natural processes in the degradation of open-air rock-art sites : an urgency intervention scale to inform conservation

Fernandes, Antonio Pedro Martins do Mota Batarda January 2012 (has links)
Open-air rock-art forms one of the most widely distributed categories of prehistoric material culture with examples recognized across the Old and New Worlds. It is also one of the most threatened features of human heritage and is susceptible to accelerated decay as a result of anthropogenic and natural processes. Much attention has previously been given to the impact of identifiably human activities and their mitigation, but the aim of this research is to redress the balance and focus on understanding the short-, medium-, and long-term impacts of natural processes. The main objectives of research are to identify open-air rock-art natural degradation causes, create a suitable method to assess the state of conservation of any given engraved outcrop of the Côa Valley rock-art complex and develop a urgency scale for conservation interventions. The urgency scale will be established by thoroughly examining a sample of the most – in terms of conservation – representative engraved outcrops. Since more than one thousand outcrops with rock-art still subsist today, it would be impossible to examine them all. Therefore, a sample comprising outcrops that possess most, if not all, of the variables that might affect stability and conservation state will be chosen. Some of the issues to consider are weathering and erosion of outcrops, or slope gradient and aspect of the hills where these are located. Such phenomena as biological colonization, rainwater percolation or chemical exchanges at surface level will also be analyzed. The expected end result of research is the creation of a method to determine the condition of outcrops and to identify methodically those in most urgent need of conservation. As a result, informed conservation action plans can be systematically tailored to suit specific natural conditions. Moreover, conservation interventions can be prioritized within a total universe of 1000 outcrops with rock-art.

Development of an in vitro model to investigate the effect of chemotherapeutic treatment on mesenchymal stromal cells

May, J. E. January 2010 (has links)
No description available.

Proteomic responses of uninfected tissues of pea plants infected by root-knot nematode, Fusarium and downy mildew pathogens

Ghazala, Al-Sadek Mohammed Salem January 2012 (has links)
Peas suffer from several diseases, and there is a need for accurate, rapid in-field diagnosis. This study used proteomics to investigate the response of pea plants to infection by the root knot nematode Meloidogyne hapla, the root rot fungus Fusarium solani and the downy mildew oomycete Peronospora viciae, and to identify potential biomarkers for diagnostic kits. A key step was to develop suitable protein extraction methods. For roots, the Amey method (Chuisseu Wandji et al., 2007), was chosen as the best method. The protein content of roots from plants with shoot infections by P. viciae was less than from non-infected plants. Specific proteins that had decreased in abundance were (1->3)-beta-glucanase, alcohol dehydrogenase 1, isoflavone reductase, malate dehydrogenase, mitochondrial ATP synthase subunit alpha, eukaryotic translation inhibition factor, and superoxide dismutase. No proteins increased in abundance in the roots of infected plants. For extraction of proteins from leaves, the Giavalisco method (Giavalisco et al., 2003) was best. The amount of protein in pea leaves decreased by age, and also following root infection by F. solani and M. hapla at six weeks post-inoculation. F. solani caused a decrease in abundance of isocitrate dehydrogenase, glycerate dehydrogenase, carbonic anhydrase, oxygen evolving enhancer protein 2 (OEE2), phosphoglycerate kinase, chloroplastic and one unknown protein. Some leaf proteins increased in abundance, and included heat shock-related proteins (HSP70) and two unknown proteins. Proteins that decreased in leaves following root infection by M. hapla six week post-inoculation were RuBisCo large subunit, fructose bisphosphate aldolase 2, carbonic anhydrase, OEE1, OEE2, OEE3, RuBisCo small subunit and a 28KDa ribonucleoprotein. Some proteins increased in abundance, such as HSP70, fructose bisphosphate aldolase 1 and trypsin. In contrast to the decrease in protein observed at six weeks post-inoculation, the amount of protein increased in leaves three weeks after inoculation of roots with M. hapla. Root infection by both M. hapla and F. solani caused a reduction in leaf area, and also a reduction in fresh and dry weight of the shoot and root systems. The use of digital imaging and visible and infra-red light to study the changes in leaves was explored in this study. A clear difference was visible between leaves from healthy plants and between those from M. hapla and F. solani infected plants when imaged using a normal digital camera. In contrast, no clear differences were noticed between leaves of healthy, M. hapla and F. solani infected plants when using an infra-red camera with 850 nm wavelength light. This study indicates that specific proteins are altered in abundance in leaves following root infection, and provides the basis for future studies to develop rapid diagnostic tests.

An examination of the structural chemistry associated with transition metal redox reactions in lubricating oil formulations

Peacock, Carol Ann January 2001 (has links)
No description available.

Flow and equilibration studies in superheated turbulent jets

Adlington, Ronald Kenneth January 1975 (has links)
No description available.

Design and evaluation of an information system for structured learning resource materials

Barker, Anne Lesley January 1979 (has links)
No description available.

Page generated in 0.0392 seconds