4 resultados para World-wide-web

em CORA - Cork Open Research Archive - University College Cork - Ireland


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At a time when technological advances are providing new sensor capabilities, novel network capabilities, long-range communications technologies and data interpreting and delivery formats via the World Wide Web, we never before had such opportunities to sense and analyse the environment around us. However, the challenges exist. While measurement and detection of environmental pollutants can be successful under laboratory-controlled conditions, continuous in-situ monitoring remains one of the most challenging aspects of environmental sensing. This paper describes the development and test of a multi-sensor heterogeneous real-time water monitoring system. A multi-sensor system was deployed in the River Lee, County Cork, Ireland to monitor water quality parameters such as pH, temperature, conductivity, turbidity and dissolved oxygen. The R. Lee comprises of a tidal water system that provides an interesting test site to monitor. The multi-sensor system set-up is described and results of the sensor deployment and the various challenges are discussed.

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The Internet and World Wide Web have had, and continue to have, an incredible impact on our civilization. These technologies have radically influenced the way that society is organised and the manner in which people around the world communicate and interact. The structure and function of individual, social, organisational, economic and political life begin to resemble the digital network architectures upon which they are increasingly reliant. It is increasingly difficult to imagine how our ‘offline’ world would look or function without the ‘online’ world; it is becoming less meaningful to distinguish between the ‘actual’ and the ‘virtual’. Thus, the major architectural project of the twenty-first century is to “imagine, build, and enhance an interactive and ever changing cyberspace” (Lévy, 1997, p. 10). Virtual worlds are at the forefront of this evolving digital landscape. Virtual worlds have “critical implications for business, education, social sciences, and our society at large” (Messinger et al., 2009, p. 204). This study focuses on the possibilities of virtual worlds in terms of communication, collaboration, innovation and creativity. The concept of knowledge creation is at the core of this research. The study shows that scholars increasingly recognise that knowledge creation, as a socially enacted process, goes to the very heart of innovation. However, efforts to build upon these insights have struggled to escape the influence of the information processing paradigm of old and have failed to move beyond the persistent but problematic conceptualisation of knowledge creation in terms of tacit and explicit knowledge. Based on these insights, the study leverages extant research to develop the conceptual apparatus necessary to carry out an investigation of innovation and knowledge creation in virtual worlds. The study derives and articulates a set of definitions (of virtual worlds, innovation, knowledge and knowledge creation) to guide research. The study also leverages a number of extant theories in order to develop a preliminary framework to model knowledge creation in virtual worlds. Using a combination of participant observation and six case studies of innovative educational projects in Second Life, the study yields a range of insights into the process of knowledge creation in virtual worlds and into the factors that affect it. The study’s contributions to theory are expressed as a series of propositions and findings and are represented as a revised and empirically grounded theoretical framework of knowledge creation in virtual worlds. These findings highlight the importance of prior related knowledge and intrinsic motivation in terms of shaping and stimulating knowledge creation in virtual worlds. At the same time, they highlight the importance of meta-knowledge (knowledge about knowledge) in terms of guiding the knowledge creation process whilst revealing the diversity of behavioural approaches actually used to create knowledge in virtual worlds and. This theoretical framework is itself one of the chief contributions of the study and the analysis explores how it can be used to guide further research in virtual worlds and on knowledge creation. The study’s contributions to practice are presented as actionable guide to simulate knowledge creation in virtual worlds. This guide utilises a theoretically based classification of four knowledge-creator archetypes (the sage, the lore master, the artisan, and the apprentice) and derives an actionable set of behavioural prescriptions for each archetype. The study concludes with a discussion of the study’s implications in terms of future research.

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Lactococcus lactis is used extensively world-wide for the production of fermented dairy products. Bacteriophages (phages) infecting L. lactis can result in slow or incomplete fermentations, or may even cause total fermentation failure. Therefore, bacteriophages disrupting L. lactis fermentation are of economic concern. This thesis employed a multifaceted approach to investigate various molecular aspects of phage-host interaction in L. lactis. The genome sequence of an Irish dairy starter strain, the prophage-cured L. lactis subsp. cremoris UC509.9, was studied. The 2,250,427 bp circular chromosome represents the smallest among its sequenced lactococcal equivalents. The genome displays clear genetic adaptation to the dairy niche in the form of extensive reductive evolution. Gene prediction identified 2066 protein-encoding genes, including 104 which showed significant homology to transposase-specifying genes. Over 9 % of the identified genes appear to be inactivated through stop codons or frame shift mutations. Many pseudogenes were found in genes that are assigned to carbohydrate and amino acid transport and metabolism orthologous groups, reflecting L. lactis UC509.9’s adaptation to the lactose and casein-rich dairy environment. Sequence analysis of the eight plasmids of L. lactis revealed extensive adaptation to the dairy environment. Key industrial phenotypes were mapped and novel lactococcal plasmid-associated genes highlighted. In addition to chromosomally-encoded bacteriophage resistance systems, six functional such systems were identified, including two abortive infection systems, AbiB and AbiD1, explaining the observed phage resistance of L. lactis UC509.9 Molecular analysis suggests that the constitutive expression of AbiB is not lethal to cells, suggesting the protein is expressed in an un/inactivated form. Analysis of 936 species phage sk1-escape mutants of AbiB revealed that all such mutants harbour mutations in orf6, which encodes the major capsid protein. Results suggest that the major capsid protein is required for activation of the AbiB system, although this requires furrther investigations. Temporal transcriptomes of L. lactis UC509.9 undergoing lytic infection with either one of two distinct bacteriophages, Tuc2009 and c2, was determined and compared to the transcriptome of uninfected UC509.9 cells. Whole genome microarrays performed at various time-points post-infection demonstrated a rather modest impact on host transcription. Alterations in the UC509.9 transcriptome during lytic infection appear phage-specific, with a relatively small number of differentially transcribed genes shared between infection with either Tuc2009 or c2. Transcriptional profiles of both bacteriophages during lytic infection was shown to generally correlate with previous studies and allowed the confirmation of previously predicted promoter sequences. Bioinformatic analysis of genomic regions encoding the presumed cell wall polysaccharide (CW PS) biosynthesis gene cluster of several strains of L. lactis was performed. Results demonstrate the presence of three dominant genetic types of this gene cluster, termed type A, B and C. These regions were used for the development of a multiplex PCR to identify CW PS genotype of various lactococcal strains. Analysis of 936 species phage receptor binding protein phylogeny (RBP) and CW PS genotype revealed an apparent correlation between RBP phylogeny and CW PS type, thereby providing a partial explanation for the observed narrow host range of 936 phages. Further analysis of the genetic locus encompassing the presumed CW PS biosynthesis operon of eight strains identified as belonging to the CW PS C (geno)type, revealed the presence of a variable region among the examined strains. The obtained comparative analysis allowed for the identification of five subgroups of the C type, named C1 to C5. We purified an acidic polysaccharide from the cell wall of L. lactis 3107 (C2 subtype) and confirmed that it is structurally different from the CW PS of the C1 subtype L. lactis MG1363. Combinations of genes from the variable region of C2 subtype were amplified from L. lactis 3107 and introduced into a mutant of the C1 subtype L. lactis NZ9000 (a direct derivative of MG1363) deficient in CW PS biosynthesis. The resulting recombinant mutant synthesized a CW PS with a composition characteristic for that of the C2 subtype L. lactis 3107 and not the wildtype C1 L. lactis NZ9000. The recombinant mutant exhibited a changed phage resistance/sensitivity profile consistent with that of L. lactis 3107, which unambiguously demonstrated that L. lactis 3107 CW PS is the host cell surface receptor of two bacteriophages belonging to the P335 species as well as phages that are member of the 936 species. The research presented in this thesis has significantly advanced our understanding of L. lactis bacteriophage-host interactions in several ways. Firstly, the examination of plasmidencoded bacteriophage resistance systems has allowed inferences to be made regarding the mode of action of AbiB, thereby providing a platform for further elucidation of the molecular trigger of this system. Secondly, the phage infection transcriptome data presented, in addition to previous work, has made L. lactis a model organism in terms of transcriptomic studies of bacteriophage-host interactions. And finally, the research described in this thesis has for the first time explicitly revealed the nature of a carbohydrate bacteriophage receptor in L. lactis, while also providing a logical explanation for the observed narrow host ranges exhibited by 936 and P335 phages. Future research in discerning the structures of other L. lactis CW PS, combined with the determination of the molecular interplay between receptor binding proteins of these phages and CW PS will allow an in depth understanding of the mechanism by which the most prevalent lactococcal phages identify and adsorb to their specific host.

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Background: On-going surveillance of behaviours during pregnancy is an important but overlooked population health activity that is particularly lacking in Ireland. Few, if any, nationally representative estimates of most maternal behaviours and experiences are available. While on-going surveillance of maternal behaviours has not been a priority thus far in European countries including Ireland, on-going surveillance was identified as a key priority in the United States (US) during the 1980’s when the Pregnancy Risk Assessment Monitoring System (PRAMS), was established. Today, PRAMS is the only surveillance programme of maternal behaviours and experiences world-wide. Although on-going prevalence estimates are required in Ireland, studies which examine the offspring health effects of maternal behaviours are also required, since various questions regarding maternal exposures and their offspring health effects remain unanswered. Gestational alcohol consumption is one such important maternal exposure which is common in pregnancy, though its offspring health effects are unclear, particularly at lower or moderate levels. Thus, guidelines internationally have not reached consensus on safe alcohol recommendations for pregnant women. The aims of this thesis are to implement the PRAMS in Ireland (PRAMS Ireland), to describe the prevalence of health behaviours around the time of pregnancy in Ireland and to examine the effect of health behaviours on pregnancy and child outcomes (specifically the relationship between alcohol use during pregnancy and infant and child growth). Structure: In Chapter 1, a brief background and rationale for the work, as well as the thesis aims and objective is provided. A detailed description of the design and implementation of PRAMS Ireland is described in Chapter 2. Chapter 3 and Chapter 4 describe the methodological results of the implementation of the PRAMS Ireland pilot study and PRAMS Ireland main study. In Chapter 5, a comparison of alcohol prevalence in two Irish studies (PRAMS Ireland and Growing up in Ireland (GUI)) and one multi-centre prospective cohort study, Screening for Pregnancy Endpoints (SCOPE) Study is detailed. Chapter 6 describes findings on adherence to National Clinical Guidelines on health behaviours and nutrition around the time of pregnancy in PRAMS Ireland. Findings on exposure to alcohol use in pregnancy and infant growth outcomes are described in Chapter 7 and Chapter 8. The results of analysis conducted to examine the impact of gestational alcohol use on offspring growth trajectories to age ten are described in Chapter 9. Finally, a discussion of the findings, strengths and limitations of the thesis, direction for future research, policy, practice and public health implications are discussed in Chapter 10.Results: Implementation of PRAMS: PRAMS may be an effective system for the surveillance of health behaviours around the time of pregnancy in the Irish context. PRAMS Ireland had high response rates (67% and 61% response rates in the pilot and main study respectively), high item completion rates and valid prevalence estimates for many health behaviours. Examining prevalence of health behaviours: We found high levels of alcohol consumption before and during pregnancy, poor adherence to healthy diets and high levels of smoking before and during pregnancy among women in Ireland. Socially disadvantaged women had higher rates of deleterious health behaviours before pregnancy, although women with the most deleterious behaviour profiles before pregnancy appeared to experience the greatest gain in protective health behaviours during pregnancy. The impact of alcohol use on infant and offspring growth: We found that low and moderate levels of alcohol use did not impact on birth outcomes or offspring growth whereas heavy alcohol consumption resulted in reduced birth length and birth weight; however, this finding was not consistently observed across all studies. Selection, reporting and confounding biases which are common in observational research could be masking harmful effects. Conclusion: PRAMS is a valid and feasible method of surveillance of health behaviours around the time of pregnancy in Ireland. A surveillance program of maternal behaviours and experiences is immediately warranted due to high levels of deleterious health behaviours around the time of pregnancy in Ireland. Although our results do not indicate any evidence of harm, given the quality of evidence available, abstinence and advice of abstinence from alcohol may be the most prudent choice for patients and healthcare professionals respectively. Further studies of the effects of gestational alcohol use are required; particularly those which can reduce selection bias, reporting bias and confounding.