1,734 research outputs found

    Evaluating E-learning systems success : an empirical study

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    E-learning, as a direct result of the integration of technology and education, has emerged as a powerful medium of learning particularly using Internet technologies. The undeniable significance of e-learning in education has led to a massive growth in the number of e-learning courses and systems offering different types of services. Thus, evaluation of e-learning -systems is vital to ensure successful delivery, effective use, and positive impacts on learners. Based on an intensive review of the literature, a comprehensive model has been developed which provides a holistic picture and identifies different levels of success related to a broad range of success determinants. The model has been empirically validated by fitting the model to data collected from 563 students engaged with an e-learning system in one of the UK universities through a quantitative method of Partial Least Squares - Structural Equation Modelling (PLS-SEM). The determinants of e-learning perceived satisfaction are technical system quality, information quality, service quality, support system quality, learner quality, instructor quality, and perceived usefulness, which together explain 71.4% of the variance of perceived satisfaction. The drivers of perceived usefulness are technical system quality, information quality, support system quality, learner quality, and instructor quality, and these explain 54.2% of the variance of perceived usefulness. Four constructs were found to be the determinants of e-learning use, namely educational system quality, support system quality, learner quality, and perceived usefulness, and together they account for 34.1%. Finally, 64.7% of the variance of e-learning benefits was explained by perceived usefulness, perceived satisfaction, and use

    Micro notes application for education : a proposed mobile micro note-taking architecture

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    Given the massive uptake in the domain of information and communication technology, there is great potential for integrating social media technologies with learning processes at universities. Social Network Sites (SNS), e.g. Twitter and Facebook, have been used in various educational activities. However, the use of such sites in educational activities is still generic often confining itself to aspects related to creating module notebooks. Hence, this study aims to employ SNS, and more specifically the features of Twitter, in the educational process so as to make it more effective than has been the case hitherto. Mobile technologies have also formed the basis for innovative note-taking solutions to be used by students in the classroom to cover the shortcomings of traditional notes. Based on mobile technologies and SNS features, this study proposes an architecture that provides undergraduate students with a new innovative note-taking tool. The architecture has been proposed to fit the students’ needs at higher education level as regards their note-taking practice. The proposed architecture was built based on a MVC three tier model that is used for interaction application. This issue has not been investigated in the literature and thus its usefulness to the learning process is still unexplored

    A low-voltage retarding-field Mott polarimeter for photocathode characterization

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    Nuclear physics experiments at Thomas Jefferson National Accelerator Facility's CEBAF rely on high polarization electron beams. We describe a recently commissioned system for prequalifying and studying photocathodes for CEBAF with a load-locked, low-voltage polarized electron source coupled to a compact retarding-field Mott polarimeter. The polarimeter uses simplified electrode structures and operates from 5 to 30 kV. The effective Sherman function for this device has been calibrated by comparison with the CEBAF 5 MeV Mott polarimeter. For elastic scattering from a thick gold target at 20 keV, the effective Sherman function is 0.201(5). Its maximum efficiency at 20 keV, defined as the detected count rate divided by the incident particle current, is 5.4(2) x 10-4, yielding a figure-of-merit, or analyzing power squared times efficiency, of 1.0(1) x 10-5. The operating parameters of this new polarimeter design are compared to previously published data for other compact Mott polarimeters of the retarding-field type.Comment: 9 figure

    Renal neuroendocrine control of desiccation and cold tolerance by Drosophila suzukii

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    Background: Neuropeptides are central to the regulation of physiological, and behavioural processes in insects, directly impacting cold and desiccation survival. However, little is known about the control mechanisms governing these responses in D. suzukii. The close phylogenetic relationship of D. suzukii with D. melanogaster allows, through genomic and functional studies, an insight into the mechanisms directing stress tolerance in D. suzukii. Results: Capa, Leucokinin, DH44 and DH31 neuropeptides demonstrate a high level of conservation between D. suzukii and D. melanogaster with respect to peptide sequences, neuronal expression, receptor localisation, and diuretic function in the Malpighian tubules. Despite D. suzukii’s ability to populate cold environments, they proved sensitive to both cold and desiccation. Furthermore, in D. suzukii, Capa acts as a desiccation-and cold stress-responsive gene, while DH44 gene expression is increased only after desiccation exposure, and the LK gene after nonlethal cold stress recovery. Conclusion: This study provides a comparative investigation into stress tolerance mediation by neuroendocrine signalling in two Drosophila species, providing evidence that similar signalling pathways control fluid secretion in the Malpighian tubules. Identifying processes governing specific environmental stresses affecting D. suzukii could lead to the development of targeted integrated management strategies to control insect pest populations

    Mechanical circulatory support for refractory cardiogenic shock post-acute myocardial infarction-a decade of lessons.

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    There are 0.9 catheterization labs per 100,000 inhabitants in Scotland for percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), which are much less accessible to patients in remote and rural areas. An uncommon but sinister sequalae following AMI is cardiogenic shock (CS) that could be refractory to inotropic support. CS complicates 5-15% of AMIs occurring in ST-segment elevation myocardial infarctions (STEMIs). Outcomes of CS are poor with mortalities of up to 90% reported in the literature in the absence of experienced care. We report our experience as the tertiary referral centre in Scotland for MCS and heart transplantation over 8 years. A retrospective review of prospectively collected data was undertaken on all patients registered to the MCS service. The database was interrogated for patient demographics, type of mechanical circulatory support (MCS) and duration of MCS support, PCI-outcomes and survival to 30 days. A time-to-event analysis was performed using patient survival as the primary outcome measure. Twenty-three patients (16 male, 7 females) were included. The median age of the patients as 50 years (range, 45-56 years). VA-ECMO was the initial MCS of choice in 17 (73.9%) patients with BIVAD for 4 (17.4%) patients and LVAD for 2 (8.7%) patients. Thirty-day mortality was 21.8% in this cohort, however survival to discharge was 52.2%. Eleven (47.8%) patients recovered without the need for any further support, however only 9 (81.8%) patients in this subgroup survived to discharge. Three (13.0%) patients received a durable LVAD. In this subgroup, one patient was transplanted whereas two patients died due to complications while on support. The median length of in-hospital MCS support was 4 days. Median in-hospital stay was 27 days. Long-term follow up of up to 8 years demonstrates a high mortality beyond 30-day up to the first 6-month post MCS support. MCS usage in these patients carries a high mortality in the early post-implantation period. However, there is a significant benefit to patients who survive the initial bridging period to recovery or destination therapy

    Mechanical circulatory support for refractory cardiogenic shock post-acute myocardial infarction-a decade of lessons.

    Get PDF
    There are 0.9 catheterization labs per 100,000 inhabitants in Scotland for percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), which are much less accessible to patients in remote and rural areas. An uncommon but sinister sequalae following AMI is cardiogenic shock (CS) that could be refractory to inotropic support. CS complicates 5-15% of AMIs occurring in ST-segment elevation myocardial infarctions (STEMIs). Outcomes of CS are poor with mortalities of up to 90% reported in the literature in the absence of experienced care. We report our experience as the tertiary referral centre in Scotland for MCS and heart transplantation over 8 years. A retrospective review of prospectively collected data was undertaken on all patients registered to the MCS service. The database was interrogated for patient demographics, type of mechanical circulatory support (MCS) and duration of MCS support, PCI-outcomes and survival to 30 days. A time-to-event analysis was performed using patient survival as the primary outcome measure. Twenty-three patients (16 male, 7 females) were included. The median age of the patients as 50 years (range, 45-56 years). VA-ECMO was the initial MCS of choice in 17 (73.9%) patients with BIVAD for 4 (17.4%) patients and LVAD for 2 (8.7%) patients. Thirty-day mortality was 21.8% in this cohort, however survival to discharge was 52.2%. Eleven (47.8%) patients recovered without the need for any further support, however only 9 (81.8%) patients in this subgroup survived to discharge. Three (13.0%) patients received a durable LVAD. In this subgroup, one patient was transplanted whereas two patients died due to complications while on support. The median length of in-hospital MCS support was 4 days. Median in-hospital stay was 27 days. Long-term follow up of up to 8 years demonstrates a high mortality beyond 30-day up to the first 6-month post MCS support. MCS usage in these patients carries a high mortality in the early post-implantation period. However, there is a significant benefit to patients who survive the initial bridging period to recovery or destination therapy

    Gastrostomy in the era of minimally invasive head and neck cancer surgery

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142924/1/lary26829.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142924/2/lary26829_am.pd

    Members of the chloride intracellular ion channel protein family demonstrate glutaredoxin-like enzymatic activity

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    © 2015 Al Khamici et al. The Chloride Intracellular Ion Channel (CLIC) family consists of six evolutionarily conserved proteins in humans. Members of this family are unusual, existing as both monomeric soluble proteins and as integral membrane proteins where they function as chloride selective ion channels, however no function has previously been assigned to their soluble form. Structural studies have shown that in the soluble form, CLIC proteins adopt a glutathione S-transferase (GST) fold, however, they have an active site with a conserved glutaredoxin monothiol motif, similar to the omega class GSTs. We demonstrate that CLIC proteins have glutaredoxin-like glutathione-dependent oxidoreductase enzymatic activity. CLICs 1, 2 and 4 demonstrate typical glutaredoxin-like activity using 2-hydroxyethyl disulfide as a substrate. Mutagenesis experiments identify cysteine 24 as the catalytic cysteine residue in CLIC1, which is consistent with its structure. CLIC1 was shown to reduce sodium selenite and dehydroascorbate in a glutathione-dependent manner. Previous electrophysiological studies have shown that the drugs IAA-94 and A9C specifically block CLIC channel activity. These same compounds inhibit CLIC1 oxidoreductase activity. This work for the first time assigns a functional activity to the soluble form of the CLIC proteins. Our results demonstrate that the soluble form of the CLIC proteins has an enzymatic activity that is distinct from the channel activity of their integral membrane form. This CLIC enzymatic activity may be important for protecting the intracellular environment against oxidation. It is also likely that this enzymatic activity regulates the CLIC ion channel function
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