177 resultados para 364.154

em Queensland University of Technology - ePrints Archive


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Methyl, methyl-d(3), and ethyl hydroperoxide anions (CH3OO-, CD3OO-, and CH3CH2OO-) have been prepared by deprotonation of their respective hydroperoxides in a stream of helium buffer, gas. Photodetachment with 364 nm (3.408 eV) radiation was used to measure the adiabatic electron affinities: EA[CH3OO, (X) over tilde (2)A"] = 1.161 +/- 0.005 eV, EA[CD3OO, (X) over tilde (2)A"] = 1.154 +/- 0.004 eV, and EA[CH3CH2OO, (X) over tilde (2)A"] = 1.186 +/- 0.004 eV. The photoelectron spectra yield values for the term energies: DeltaE((X) over tilde 2A"-(A) over tilde 2A')[CH3OO] = 0.914 +/- 0.005 eV, DeltaE((X) over tilde (2)A"-(A) over tilde 2A') [CD3OO] = 0.913 +/- 0.004 eV, and DeltaE((X) over tilde (2)A"-(A) over tilde (2)A')[CH3CH2OO] = 0.938 +/- 0.004 eV. A localized RO-O stretching mode was observed near 1100 cm(-1) for the ground state of all three radicals, and low-frequency R-O-O bending modes are also reported. Proton-transfer kinetics of the hydroperoxides have been measured in a tandem flowing afterglow-selected ion flow tube k(FA-SIFT) to determine the gas-phase acidity of the parent hydroperoxides: Delta (acid)G(298)(CH3OOH) = 367.6 +/- 0.7 kcal mol(-1), Delta (acid)G(298)(CD3OOH) = 367.9 +/- 0.9 kcal mol(-1), and Delta (acid)G(298)(CH3CH2OOH) = 363.9 +/- 2.0 kcal mol(-1). From these acidities we have derived the enthalpies of deprotonation: Delta H-acid(298)(CH3OOH) = 374.6 +/- 1.0 kcal mol(-1), Delta H-acid(298)(CD3OOH) = 374.9 +/- 1.1 kcal mol(-1), and Delta H-acid(298)(CH2CH3OOH) = 371.0 +/- 2.2 kcal mol(-1). Use of the negative-ion acidity/EA cycle provides the ROO-H bond enthalpies: DH298(CH3OO-H) 87.8 +/- 1.0 kcal mol(-1), DH298(CD3OO-H) = 87.9 +/- 1.1 kcal mol(-1), and DH298(CH3CH2OO-H) = 84.8 +/- 2.2 kcal mol(-1). We review the thermochemistry of the peroxyl radicals, CH3OO and CH3CH2OO. Using experimental bond enthalpies, DH298(ROO-H), and CBS/APNO ab initio electronic structure calculations for the energies of the corresponding hydroperoxides, we derive the heats of formation of the peroxyl radicals. The "electron affinity/acidity/CBS" cycle yields Delta H-f(298)[CH3OO] = 4.8 +/- 1.2 kcal mol(-1) and Delta H-f(298)[CH3CH2OO] = -6.8 +/- 2.3 kcal mol(-1).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We generalize the classical notion of Vapnik–Chernovenkis (VC) dimension to ordinal VC-dimension, in the context of logical learning paradigms. Logical learning paradigms encompass the numerical learning paradigms commonly studied in Inductive Inference. A logical learning paradigm is defined as a set W of structures over some vocabulary, and a set D of first-order formulas that represent data. The sets of models of ϕ in W, where ϕ varies over D, generate a natural topology W over W. We show that if D is closed under boolean operators, then the notion of ordinal VC-dimension offers a perfect characterization for the problem of predicting the truth of the members of D in a member of W, with an ordinal bound on the number of mistakes. This shows that the notion of VC-dimension has a natural interpretation in Inductive Inference, when cast into a logical setting. We also study the relationships between predictive complexity, selective complexity—a variation on predictive complexity—and mind change complexity. The assumptions that D is closed under boolean operators and that W is compact often play a crucial role to establish connections between these concepts. We then consider a computable setting with effective versions of the complexity measures, and show that the equivalence between ordinal VC-dimension and predictive complexity fails. More precisely, we prove that the effective ordinal VC-dimension of a paradigm can be defined when all other effective notions of complexity are undefined. On a better note, when W is compact, all effective notions of complexity are defined, though they are not related as in the noncomputable version of the framework.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The advantages of bundling e-journals together into publisher collections include increased access to information for the subscribing institution’s clients, purchasing cost-effectiveness and streamlined workflows. Whilst cataloguing a consortial e-journal collection has its advantages, there are also various pitfalls and the author outlines efforts by the CAUL (Council of Australian University Libraries) Consortium libraries to further streamline this process, working in conjunction with major publishers. Despite the advantages that publisher collections provide, pressures to unbundle existing packages continue to build, fuelled by an ever-increasing selection of available electronic resources; decreases in, and competing demands upon, library budgets; the impact of currency fluctuations; and poor usage for an alarmingly high proportion of collection titles. Consortial perspectives on bundling and unbundling titles are discussed, including options for managing the addition of new titles to the bundle and why customising consortial collections currently does not work. Unbundling analyses carried out at Queensland University of Technology during 2006 to 2008 prior to the renewal of several major publisher collections are presented as further case studies which illustrate why the “big deal” continues to persist.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The primary aims of scoliosis surgery are to halt the progression of the deformity, and to reduce its severity (cosmesis). Currently, deformity correction is measured in terms of posterior parameters (Cobb angles and rib hump), even though the cosmetic concern for most patients is anterior chest wall deformity. In this study, we propose a new measure for assessing anterior chest wall deformity and examine the correlation between rib hump and the new measure. 22 sets of CT scans were retrieved from the QUT/Mater Paediatric Spinal Research Database. The Image J software (NIH) was used to manipulate formatted CT scans into 3-dimensional anterior chest wall reconstructions. A ‘chest wall angle’ was then measured in relation to the first sacral vertebral body. The chest wall angle was found to be a reliable tool in the analysis of chest wall deformity. No correlation was found between the new measure and rib hump angle. Since rib hump has been shown to correlate with vertebral rotation on CT, this suggests that there maybe no correlation between anterior and posterior deformity measures. While most surgical procedures will adequately address the coronal imbalance & posterior rib hump elements of scoliosis, they do not reliably alter the anterior chest wall shape. This implies that anterior chest wall deformity is to a large degree an intrinsic deformity, not directly related to vertebral rotation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Despite the increased offering of online communication channels to support web-based retail systems, there is limited marketing research that investigates how these channels act singly, or in combination with online channels, to influence an individual' s intention to purchase online. If the marketer's strategy is to encourage online transactions, this requires a focus on consumer acceptance of the web-based transaction technology, rather than the purchase of the products per se. The exploratory study reported in this paper examines normative influences from referent groups in an individual's on and offline social communication networks that might affect their intention to use online transaction facilities. The findings suggest that for non-adopters, there is no normative influence from referents in either network. For adopters, one online and one offline referent norm positively influenced this group's intentions to use online transaction facilities. The implications of these findings are discussed together with future research directions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Rural and remote schools make up a significant portion of Australian schools. Although there are rural schools that exceed 500 students, the Australian Bureau of Statistics (ABS) (2008) reports that 2,188 Australian primary schools have enrolment numbers less than 100. Rural schools need a supply of good teachers; however many universities involved in teacher education are located in city areas. For example, Queensland University of Technology is city-based, generating the highest number of early career teachers for Queensland including teachers for rural schools. Given the number of graduates and the number of rural schools, it seems likely that early career teachers will have opportunities for teaching in these settings, which also means living within a rural community. This chapter will discuss the nature of teaching in rural and remote schools, the challenges, the rewards and the importance of working closely with the local community. It is hoped that by understanding rural and remote schools, early career teachers can make informed decisions that will influence their future career prospects.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

During the past century, significant improvements in the prevention, detection and treatment of infectious disease have positively impacted upon quality and quantity of life for many people worldwide. Despite this progress, there are large numbers of people currently living in developing regions of the world where infectious disease continues unabated. SurfAid International is a humanitarian organisation that has brought significant health improvements to the people living on the Mentawai and Nias islands of Indonesia. The SurfAid International Schools Program aims to develop global citizenship and social responsibility by providing a bridge between school settings and the critical work of SurfAid International. This paper provides a rationale for the development of contextualised school based programs and identifies potential impact upon the thoughts and actions of young people in schools.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Interactive educational courseware has been adopted in diverse education sectors such as primary, secondary, tertiary education, vocational and professional training. In Malaysian educational context, the ministry of education has implemented Smart School Project that aims to increase high level of academic achievement in primary and secondary schools by using interactive educational courseware. However, many researchers have reported that many coursewares fail to accommodate the learner and teacher needs. In particular, the interface design is not appropriately designed in terms of quality of learning. This paper reviews educational courseware development process in terms of defining quality of interface design and suggests a conceptual model of interface design through the integration of design components and interactive learning experience into the development process. As a result, it defines the concept of interactive learning experience in a more practical approach in order to implement each stage of the development process in a seamless and integrated way.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

There are various principles for layout design such as balance, rhythm, unity and harmony, but each principle has often been introduced as a separate concept rather than within an integrated and systematic structure, so that designers and design students have to keep practices for the acquisition of skills. The paper seeks to develop a conceptual framework for a systematic mapping of layout design principles by using Yin and Yang and the Five Elements. Yin and Yang theory explains all natural phenomena with its own conceptual model and facilitates finding harmony and balance between the visual elements in terms of systematic and organic relations. Most common and well-known layout design principles are defined with 10 different resources such as design books and articles, and have been remapped following with the structure of Yin and Yang and the Five Elements. A systematic framework explaining the relationships of design principles was created and 32 design students participated in its efficiency test. The outcome suggests there is a high possibility that the framework can be used in professional fields and design education.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

As organisations strive to improve their capabilities in the areas of Service Management and Service-oriented Architectures (SOA), SOA Governance is becoming an increasingly important success factor. However, the concept of SOA Governance is complex and not well-understood, and the adoption of an adequate SOA Governance approach in an organisation can be difficult. Tools that support SOA Governance mostly have a technical bias and rarely address organisational aspects. In this paper, we contribute to the field by specifying a conceptual meta model for SOA Governance that integrates the structure of major IT and SOA Governance frameworks into one consolidated view. By presenting this conceptualisation and a corresponding prototypical implementation of a tool that supports SOA Governance maturity assessment, reference framework exploration and company-specific tailoring of SOA Governance, we provide insights into the first step of a Design Science research project, i.e. the development of an important IT artefact.