1,108 research outputs found
A Mobile-Based Group Quiz System to Promote Collaborative Learning and Facilitate Instant Feedback
In this paper we develop and evaluate a mobile-based questioning-answering system (MQAS) that complements traditional learning which can be used as a tool to encourage teachers to give their students mobile-based weekly group quizzes. These quizzes can provide teachers with valid information about the progress of their students and can also motivate students to work in a collaborative manner in order to facilitate the integration of their knowledge. We describe the architecture and experiences with the system
SECONDARY INTERACTIONS WHICH MODIFY REDOX AND OTHER PROPERTIES OF ORGANOMETALLIC SYSTEMS
Second coordination sphere interactions of metal centres involving hydrogen bonding, ion-pairing or dipolar bonding can play an important role in determining the physical and chemical properties of molecular and biomolecular systems. For example, the redox potentials of cubane iron-sulfur clusters in a redox protein or enzyme can range between -700mV and -400mV versus the standard hydrogen electrode as a consequence of the nature of the second-coordination sphere environment. Whilst this is largely explained in terms of hydrogen-bonding ionic, dipolar or other interactions may have a role in this. The first part of this thesis examines a model system in which a ligand based isomerism controls the redox potentials of two interconverting couples. Specifically this is a bis(cyclopentadienyl) MoV/IV system possessing a cysteinyl N,S coordinated metallocycle ring in which deployment of the amide O away or towards the metal centre by rotation is shown to lead to a ca 200 mV difference in the isomer redox potentials. The activation enthalpy for this rotation process is 18kcal mole-1 in MeCN. It is further shown that second coordination sphere interactions with an exogenous Lewis acid, Eu(fod)3 can control the isomer population, favouring the trans-amide conformation.
The second part of this thesis examines second coordination sphere interactions of coordinated cyanide in a model for the diiron subsite of [FeFe]-hydrogenase. The natural subsite in its protein environment catalyses hydrogen evolution (or uptake) at very fast rates ca 104 s-1 near the reversible potential of the H+ /1/2 H2 couple but such rates have yet to be attained in model systems. Controlling the electronic and geometric
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properties of synthetic diiron subsites by hydrogen bonding or other interactions might provide a means of attaining the turnover rates of the natural system. This work takes some first steps towards introducing second coordination sphere interactions to modify subsite properties. Firstly, a metal Lewis acid Eu(fod)3 is shown to bridge to CN ligands in the model subsite to change its spectroscopic and electrochemical behavior. Secondly, it is shown that hydrogen bonding interactions with the ligated cyanide using certain activated amides also perturbs spectroscopic and redox properties and importantly, the rate of protonation at the metal-metal bond and the stability of the resulting μ-hydride
Minority Languages in Linguistic Landscape: The case of Medina in Saudi Arabia
Linguistic landscape (LL) is the linguistic objects that mark the public space (Ben-Rafael, Shohamy, Amara, & Trumper-Hecht,2006). This dissertation examined the LL of Medina, a holy city in Saudi Arabia. The study of linguistic landscape is a site-based research, meaning any study is most likely oriented by the nature of a research site and what important observations are found in that site. Accordingly, the LL study of Medina compelled us to pay attention to the role of religion. In addition, LL study has its inextricable links to multilingualism and language policy establishing it as a marker to a given community and its language status. Therefore, this dissertation is performed to fill the gap of three unexamined concepts of LL in the context of Medina; religion, multilingualism and language policy. A total of 300 signs, accompanied with interviews and recording of soundscape were conducted in three axes; the Prophet Mosque, the Central Zone, and Modern Streets. The data were analyzed quantitatively relied on several types of categorizations; Top-down vs Bottom-up, Language Arrangement, Score-system, and Religious content. The qualitative analysis revealed three themes relevant to understanding the construction of the LL of Medina; religion, language policy, minority languages, and globalization. The investigation yielded valuable insights into the language ecology of the city and the ways in which everyday citizens and visitors to the city experienced the multilingual environment. The findings indicated that religion, to a large extent, contributes in shaping the public sphere of Medina in different applications such as to show the citys identity, and to introduce its holiness. In commercial signs, religious elements were commodified to appeal to customers, as well as to construct tokenism around a product. The study also found that in some parts of Medina multilingualism is a normal and everyday part of public life. Primarily, because of the religious importance of the Prophet Mosque that is a focal point of the city, and prime destination for religious pilgrims and visitors. The varied methods and analysis in this study led to a complex picture of the LL, and subsequently, understanding of the language policy of Medina. While Arabic is the dominant language in the city, multiple languages are also used in official and nonofficial signs, suggesting that there is permissible use of different languages, and that government was aware of the need to disseminate messages and religious education to international visitors
Cost overrun causality model in Saudi Arabian public sector construction projects.
Construction performance in Saudi public projects has been poor over the years, with 70% of projects considered as failures and costing the country over 1 trillion SAR (over £202 billion) between 2005 and 2015. The project delivery mechanism used to deliver construction projects is one of the main reasons for such poor performance, as all service providers (consultant, designer, and contractor) are chosen based on the lowest price. The contract evaluation shows that contractors hold most of a project's risks and suffer a cost overrun problem, thereby positioning them as the weakest link in the procurement chain. This study aims to develop a contractors' cost overrun causality model in the Saudi public sector. A systematic literature review was performed and revealed three schools of thought regarding the investigation and identification of cost overrun causes. However, none of the three schools has addressed the limitations of exploring the interaction between any causes identified and then linking root causes with a direct cause, nor including the effects of the context and the process that are used to develop construction projects. Exploring the interaction between causes is important, because the construction projects covered within the literature involved different stakeholders at different phases in a project's lifecycle. Moreover, it has been found that the amount and the causes of cost overrun are different based on the project's location. After the systematic literature review, this study aimed to develop a contractors' cost overrun causality model in the Saudi public sector, which would consider the effects of context, practices and processes of developing construction projects. Specifically, the research explored the commercial context of Saudi public construction project procurement under four major portfolios (economy, business, resources and regulation). Additionally, the research explored the processes and practices that are used to develop construction projects in the sector, based on the Porter model (diamond) and institutional theory. This thesis establishes the link between the commercial context and contractors' performance. Based on the systematic literature review and interviews, the causalities of cost overrun in Saudi Arabian construction projects were critically reviewed, established, classified and evaluated. The data created a "causes pool", with over two-hundred causes - these were then filtered through various means, resulting in forty-nine remaining causes. The study explores the relationship between these causes in order to create "causal paths" and, eventually, the overall model. The model-building process and the resultant outputs were reviewed by two industry experts, resulting in further refinement and simplification of the model. The final model contains forty-nine causal chains that have each been thoroughly explained. The nature of the problem investigated required this research to adopt a pragmatic and abductive approach in order to achieve its objectives. The main methodologies used were systematic literature review, case study, interviews, and project documentation. The research emphasises the importance of investigating the context and project-development process. In fact, by comparing Saudi public sector practices to established best practices, the study found that causal chains were triggered and contributed to by weaknesses within the context, process, and practices, which occur in the early stage of a project's lifecycle. However, it is established that only direct causes occur during the construction phase. Moreover, the results confirm that the current environment, regulation, practices, and behaviours of the Saudi public sector increase the risks of projects failing and damaging the construction industry. Therefore, based on the findings of the research, this thesis recommends that the Saudi public agency should: 1) adopt a project delivery approach that reduces the fragmentation in delivering a construction project, and which is tailored to the project context and characteristics; 2) adopt a new method to finance construction projects that is less affected by fluctuations in the oil economy; 3) build a long-term relationship with service providers (designers, consultants, and contractors) that is built on trust, sharing of information, and lesson learning and improvement; 4) adopt a new contract that is based on fair risk appropriation, where the risk transfer is to the most suitable party to effectively manage that risk; 5) generate general regulations and laws that transform the construction industry so as to be less affected by the external environment, more controlled by all the involved parties, and in which it becomes more attractive to invest
Cost effectiveness of bilateral prophylactic mastectomy with and without different breast reconstruction techniques versus screening in women with high risk of breast cancer in the Canadian province of Ontario
We aimed to investigate the cost-effectiveness of bilateral prophylactic mastectomy (BPM) with and without different reconstruction for the purpose of determining which strategies represent value for money. We developed a decision analytic model to project the lifetime clinical and economic consequences of different strategies. The decision model was parameterized using 10-year follow up and cost data from Ontario administrative health databases and Ontario Cancer registry. Compared to the organized screening-based strategy, surgical strategies ranged from being more effective and cost-saving and up to being associated with an incremental cost effectiveness ratio (ICER) of 9,615. BPM with immediate one-stage ADM-assisted implant breast reconstruction is the most cost-effective strategy and appears to offer the highest value for money
A Unified Mobile Payment Transaction Exchange Service (UMTES) for Next-Generation Mobile Networks
A Secure and ID Privacy-Preserving Distributed Data Collection (SPDC) framework for Internet of Things Application
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