Online learning : towards enabling choice

Education is rapidly evolving from an opportunity that was provided mainly for an elite to one that is available to a mass markets and as such is prone to the forces generated by this environment. Where, in the established pattern, commercial interest was limited mainly to the use of skills developed during the educational process, the future model of educational provision will involve extensive commercial activity in the production, delivery and marketing of material. Already there are a number of commercial companies offering framework products enabling "off the shelf solutions" for the construction and delivery of web based courses in any subject area. The commercialisation of education is underway and it is inevitable that it will be viewed, by entrepreneurs and customers alike, as any other commercial product. It would seem reasonable that the consumer should be able to evaluate the performance of these new modes of working in a similar manner to other commercial products. This paper draws together current thinking on the problems associated with evaluating computer and communication based learning

Supporting Members of Online Communities Through the Use of Visualisations

Growing numbers of people around the world are using online communities to stay in touch with each other. Online communities are now widespread, enabling meaningful communication, around various domains of interest, between users who are separated by time and distance. Despite the increasing numbers of people using online communities, there are many examples of communities which suffer from problems of falling levels of contributions from members. This thesis investigates the main principles involved in creating successful online communities. It develops a taxonomy of community interactions that provides a framework for investigating techniques that have the potential to encourage member participation. Within standard text-based online communities, problems of information overload can be prevalent, with extensive user participation often required in order to get an overview of the interaction environment and context. This thesis proposes the use of facilitation techniques, in the form of visualisations, as a means of helping users get a better understanding of the interaction context, reducing the amount of time spent by users in the information-discovery phase. A range of new, complementary visualisations are developed and tested in order to assess their efficacy in helping users to complete tasks that they would be likely to undertake during their information-discovery phase. The results of the experiments show that not only do visualisations help users achieve more accurate results in conducting simple information-discovery tasks, but they also help in completing such tasks in a more efficient manner, shrinking the amount of time spent in the information-discovery phase. Different visualisations are also shown to be more useful in different circumstances, pointing to the fact that the needs and requirements of users, and the tasks they undertake, should be considered when designing the exact nature of any potential visualisation intended to support users of online communities

Intermolecular N-H...O=C hydrogen bonding in the crystal structure of 6-amino-1,3-dimethyluracil

The 6-amino- 1,3-dimethyluracil molecule [6-amino- 1,3- dimethyl-2,4(1H,3H)-pyrimidinedione], C6H9N302 (I), lies on a crystallographic mirror plane and participates in an extensive two-dimensional hydrogen-bonding network in the solid state. Each molecule is involved in N-- H...O=C hydrogen bonding involving the amino and carbonyl gr. oups, with O...N separations of 2.894 (3) and 2.904 (3) A

The structure of triphenylmethanol, Ph₃COH

C19H160 , Mr = 260.3, trigonal, R3, a = 19.307 (3), c = 26.735 (4) A, V= 8631 (2) A 3, Z= 24, Dx = 1.20 g cm -3, a(Mo Ka) = 0.71073/~, /.~ = 0.7 cm -1, F(000) = 3312, T = 294 K, R = 0.083, wR = 0.068 for 1022 observed reflections. The structure contains hydrogen-bonded pyramidal tetramers (which have approximate 32 symmetry) with one molecule lying on a crystallographic threefold axis and another in a general position. The analysis was complicated by disorder in the crystal lattice where 71% of the tetramers occupy one orientation and 29% another; these moieties have their phenyl rings in the same volume elements in the lattice. The O...O separations in the hydrogen-bond systems are 2.884 (10) and 2.896 (11)/~ in the major tetramer and 2.80 (3) and 2.90 (3) A in the minor tetramer

Natural variation of water use and water productivity in Arabidopsis thaliana

Plant performance under reduced water availability has traditionally been assessed as drought resistance and more recently as water use efficiency (WUE). An extensive body of work has been established over the past 15 years where the natural variation of water use efficiency has been studied in the model species Arabidopsis thaliana (Arabidopsis). At the same time, a substantial degree of criticism has arisen with respect to the use of drought resistance and WUE as measures of plant performance, due to the lack of relatedness of these parameters to reproductive performance, i.e. yield. The work in this thesis is centered on understanding the physiological and genetic basis of water use and water productivity as alternative measures of plant performance under the context of reduced water availability. The first part of this study describes an extensive assessment of the natural variation of water use and water productivity in Arabidopsis in relation to numerous key physiological, phenological, and developmental parameters. Furthermore, this work concisely relates plasticity of key traits to historical climatic variation. A fundamental aspect of this work was the clarification that it is possible to estimate long term water use to a high degree of accuracy based on short term water use, i.e. soil drying rate, and flowering time. Flowering time was demonstrated to be the predominant driver of vegetative performance and water use, however it appeared to be genetically uncoupled from reproductive performance. This is in contrast to previous work that suggests WUE, measured as the ratio of C12 to C13 isotopes (δ13C), is positively associated with flowering time. Additionally, it was demonstrated that multiple commonly employed proxies of reproductive performance including total biomass, WUE, and flowering time, were not sufficient at predicting seed yield in Arabidopsis across multiple environments. The second part of this study involved the genetic dissection of water use and productivity related traits in Arabidopsis through a quantitative trait loci (QTL) mapping study and a genome wide association study (GWAS). QTL mapping using a recombinant inbred line (RIL) population developed from the ecotypes Col-0 and C24 revealed two key flowering time genes, FLOWERING LOCUS C (FLC) and FRIGIDA (FRI), as key regulators of water use. It was demonstrated that a combination of non-functional alleles of both FLC and FRI reduced long term water use via a shorted life cycle, which is again in contrast to previous work relating to the genetic dissection of WUE in Arabidopsis. Crucially, it was observed that reduced water use mediated in this fashion did not detrimentally impact upon reproductive performance. GWAS was employed subsequent to the QTL mapping in order to identify candidate genes underlying the variation for productivity as a unique trait and also as a factor of water use, i.e. water productivity. GWAS identified multiple promising candidate genes that potentially underlie the heritable genetic variation for flowering time, water use, and water productivity

Microscale Analysis of Spacecraft Heat Shields

Imagine entering Earths atmosphere after returning from the outer solar system. A heat shield less than 2 inches thick protects you from temperatures up to 2,900 Celsius (5,252 Fahrenheit). Such conditions were experienced by NASAs Stardust capsule during reentry in 2006. The only materials capable of providing the necessary protection are composites with complex microstructures. Evaluating these materials is difficult, requiring precise knowledge of their properties. To this end, NASA scientists are developing research codes to compute material properties and simulate ablation at the microscale using agency supercomputers. Utilizing these tools, along with experiments, researchers are working to push the limits of spaceflight, allowing for greater flexibility in future space missions

Process re-design and online learning

Although information technology is at the core of business process reengineering (BPR), the radical restructuring that can accompany the deployment of IT in industry does not produce consistent improvements in business performance. Failures of BPR projects are often due to insensitive implementation in the context of the interests and aspirations of the workforce. These problems present a challenge and sound a note of caution for the current and ongoing revolution in the delivery of educational content via web-centric learning environments. It is essential that new ways forward for education be chosen with care to enhance open-ended interactions between students and educators and to achieve this in an economically efficient framework. In this paper, the authors compare and contrast the introduction of new technology in industry, commerce and education and conclude by introducing details of current work incorporating an exemplar that highlights the issues faced when developing economically efficient and effective, redesigned educational systems

Representative bureaucracy: does female police leadership affect gender-based violence arrests?

Representative bureaucracy theory postulates that passive representation leads to active representation of minority groups. This article investigates the passive representation of female police officers at leadership levels and the active representation of women vis-a-vis gender-based violence arrest rates in the UK. Much of the extant research on representative bureaucracy is located at street level, with evidence showing that discretionary power of minority bureaucrats can lead to active representation. This article is focused on leadership levels of a public bureaucracy. The empirical research is based upon a panel dataset of female police officers as an independent variable and gender-based violence arrest rates as a dependent variable. The analysis reveals that there is little evidence of active representation of women by female police leadership

The photometric properties of a vast stellar substructure in the outskirts of M33

We have surveyed $\sim40$sq.degrees surrounding M33 with CFHT MegaCam in the g and i filters, as part of the Pan-Andromeda Archaeological Survey. Our observations are deep enough to resolve the top 4mags of the red giant branch population in this galaxy. We have previously shown that the disk of M33 is surrounded by a large, irregular, low-surface brightness substructure. Here, we quantify the stellar populations and structure of this feature using the PAndAS data. We show that the stellar populations of this feature are consistent with an old population with $\sim-1.6$dex and an interquartile range in metallicity of $\sim0.5$dex. We construct a surface brightness map of M33 that traces this feature to $\mu_V\simeq33$mags\,arcsec$^{-2}$. At these low surface brightness levels, the structure extends to projected radii of $\sim40$kpc from the center of M33 in both the north-west and south-east quadrants of the galaxy. Overall, the structure has an "S-shaped" appearance that broadly aligns with the orientation of the HI disk warp. We calculate a lower limit to the integrated luminosity of the structure of $-12.7\pm0.5$mags, comparable to a bright dwarf galaxy such as Fornax or AndII and slightly less than $1\$ of the total luminosity of M33. Further, we show that there is tentative evidence for a distortion in the distribution of young stars near the edge of the HI disk that occurs at similar azimuth to the warp in HI. The data also hint at a low-level, extended stellar component at larger radius that may be a M33 halo component. We revisit studies of M33 and its stellar populations in light of these new results, and we discuss possible formation scenarios for the vast stellar structure. Our favored model is that of the tidal disruption of M33 in its orbit around M31.Comment: Accepted for publication in ApJ. 17 figures. ApJ preprint forma

PAndAS' cubs: discovery of two new dwarf galaxies in the surroundings of the Andromeda and Triangulum galaxies

We present the discovery of two new dwarf galaxies, Andromeda XXI and Andromeda XXII, located in the surroundings of the Andromeda and Triangulum galaxies (M31 and M33). These discoveries stem from the first year data of the Pan-Andromeda Archaeological Survey (PAndAS), a photometric survey of the M31/M33 group conducted with the Megaprime/MegaCam wide-field camera mounted on the Canada-France-Hawaii Telescope. Both satellites appear as spatial overdensities of stars which, when plotted in a color-magnitude diagram, follow metal-poor, [Fe/H]=-1.8, red giant branches at the distance of M31/M33. Andromeda XXI is a moderately bright dwarf galaxy (M_V=-9.9+/-0.6), albeit with low surface brightness, emphasizing again that many relatively luminous M31 satellites still remain to be discovered. It is also a large satellite, with a half-light radius close to 1 kpc, making it the fourth largest Local Group dwarf spheroidal galaxy after the recently discovered Andromeda XIX, Andromeda II and Sagittarius around the Milky Way, and supports the trend that M31 satellites are larger than their Milky Way counterparts. Andromeda XXII is much fainter (M_V=-6.5+/-0.8) and lies a lot closer in projection to M33 than it does to M31 (42 vs. 224 kpc), suggesting that it could be the first Triangulum satellite to be discovered. Although this is a very exciting possibility in the context of a past interaction of M33 with M31 and the fate of its satellite system, a confirmation will have to await a good distance estimate to confirm its physical proximity to M33. Along with the dwarf galaxies found in previous surveys of the M31 surroundings, these two new satellites bring the number of dwarf spheroidal galaxies in this region to 20.Comment: 10 pages, 6 figures, accepted for publication in ApJ; v2: minor typographical correction