Independent Distance Learning – is it worth it?

This paper describes an approach to the management of the development of independent distance learning programmes (IDL) adopted by the University of Sunderland. The University through its Faculty of Education and Society has had significant success over many years of delivering a small number of programmes through IDL and this paper shares some of the areas that need to be addressed as more pressure is brought on programme deliverers to adopt the IDL approach. The paper goes on to explore the financial considerations, including the ‘at risk’ costs and the possible rewards. It is intended to act as a step-by step briefing for non-academic managers of the considerations necessary from idea to implementation, stopping short of delivery. It takes the perspective of, and its intended audience is, the managers of the process – there are many other papers and guides that deal with the distinctive pedagogy of IDL in depth and similarly many written by and for academic staff

Fossil trees, tree moulds and tree casts in the Palaeocene Mull Lava Field, NW Scotland: context, formation and implications for lava emplacement

Megafossils and macrofossils of terrestrial plants (trees, leaves, fruiting bodies, etc.) are found in sedimentary and pyroclastic units interbedded with lavas in many ancient lava fields worldwide, attesting to subaerial environments of eruption and the establishment of viable plant communities during periods of volcanic quiescence. Preservation within lava is relatively rare and generally confined to the more robust woody tissues of trees, which are then revealed in the form of charcoal, mineralised tissue or as trace fossil moulds (tree moulds) and casts of igneous rock (tree casts, s.s.). In this contribution, we document several such fossil trees (s.l.), and the lavas with which they are associated, from the Palaeocene Mull Lava Field (MLF) on the Isle of Mull, NW Scotland. We present the first detailed geological account of a unique site within the Mull Plateau Lava Formation (MPLF) at Quinish in the north of the island and provide an appraisal of the famous upright fossil tree – MacCulloch's Tree – remotely located on the Ardmeanach Peninsula on the west coast of the island, and another large upright tree (the Carsaig Tree) near Malcolm's Point in the district of Brolass, SW Mull; both occurring within the earlier Staffa Lava Formation (SLF). The taphonomy of these megafossils, along with palynological and lithofacies assessments of associated strata, allows speculation of likely taxonomic affinity and the duration of hiatuses supporting the establishment of forest/woodland communities. The Ardmeanach and Carsaig specimens, because of their size and preservation as upright (? in situ) casts enveloped by spectacularly columnar-jointed basaltic lava, appear to be unique. The aspect of these trees, the thickness of the enveloping lavas and the arrangement of cooling joints adjacent to the trees, implies rapid emplacement, ponding and slow, static cooling of voluminous and highly fluid basaltic magma. The specimens from Quinish include two prostrate casts and several prostrate moulds that collectively have a preferred orientation, aligning approximately perpendicular to that of the regional Mull Dyke Swarm, the putative fissure source of the lavas, suggesting local palaeo-flow was directed towards the WSW. The Quinish Lava is an excellent example of a classic pāhoehoe (compound-braided) type, preserving some of the best examples of surface and internal features so far noted from the Hebridean Igneous Province (HIP) lava fields. These Mull megafossils are some of the oldest recorded examples, remarkably well preserved, and form a significant feature of the island's geotourism industry

Dual-carrier Floquet circulator with time-modulated optical resonators

Spatio-temporal modulation has shown great promise as a strong time-reversal symmetry breaking mechanism that enables integrated nonreciprocal devices and topological materials at optical frequencies. However, optical modulation has its own constraints in terms of modulation index and frequency, which limit the bandwidth and miniaturization of circulators and isolators, not unlike the magneto-optical schemes that it promises to replace. Here we propose and numerically demonstrate a Floquet circulator that leverages the untapped degrees of freedom unique to time-modulated resonators. Excited by sideband-selective waveguides, the system supports broadband nonreciprocal transmission without relying on the mirror or rotational symmetries required in conventional circulators. Cascading two resonators, we create a linear three-port circulator that exhibits complete and frequency-independent forward transmission between two of the ports. This approach enables wavelength-scale circulators that can rely on a variety of modulation mechanisms

Crystal Structure Investigations of Small Heat Shock Proteins and Serine Palmitoyltransferase

The content of this thesis concerns the pursuit of protein structures from cradle to grave. This process is illustrated though the progress made on two separate proteins. The first is the serine palmitoyltransferase from Toxoplasma gondii (TgSPT). This protein is of interest as sphingolipid biosynthesis in apicomplexan parasites is currently the subject of study as a possible drug target, most notably in Plasmodium. We begin by looking at the techniques of bioinformatics used to analyse the amino acid sequence of this protein, and by calculation and comparison with other known protein sequences we are able to begin to identify the different domains of the protein and also to begin to identify their respective functions. Bioinformatic techniques are then further used in order to design constructs to be moved forward for overproduction in vivo. A number of different constructs showing significant soluble expression of various truncations of TgSPT are reported, and various techniques relating to overexpression an purification are considered, including high-throughput screening work undertaken at the Oxford Protein Production Facility. The second protein looked at is the small heat shock protein from Methanococcus jannaschii (MjHSP). This protein is used as a more tractable analogue for the human α-B-crystallin. We look here at the wild type protein as well as a mutant mimicking the disease-causing R120G mutation in α-B-crystallin, R107G, and also two different truncation mutants, mimicking the Q151X truncation. The processes relating to crystal growth and optimisation, to data collection, and to data analysis and structure solution are then considered. Finally, a redetermined structure of wild type MjHSP at significantly increased resolution, and the structure of the R107G mutant are reported

Investigations on the Mannans of Ivory Nut (Phytelephas macrocarpa)

Mannan A:1. Mannan A was extracted from delignified ivory nut shavings with 7;., potassium hydroxide solution, and the polysaccharide precipitated by acidification of the extract and addition of methylated spirits.2. The mannan, purified by means of the copper complex, gave on hydrolysis 97.6% mannose, 1.8% galactose, and o.8% glucose.3. The reducing power of the mannan determined by oxidation with alkaline hypoiodite gave a degree of polymerisation of 100, and by treatment with 3 :5- dinitrosalicylic acid, 28. The values of the chain length of mannan A obtained by these two methods were different and disagreed with the value obtained by other methods. Values of the chain length of the polysaccharide which are derived from measurement of the reducing power are, therefore, of doubtful validity.4. A triacetate was prepared which was found by Barger's method to have a degree of polymerisation of 10 -13.5. The mannan was methylated and the methylated polysaccharide hydrolysed. The hydrolysate was separated on a cellulose column and the following sugars were obtained: 2:3:4:6- tetramethyl Dmannose, 2:3:4 :6- tetramethyl D- galactose, 2:3:6 -trimethyl Dmannose, 2 :3 :4- trimethyl D- mannose, and 2:3- dimethyl D- mannose in the molar ratios of, respectively, 1.0: 0.2: 11.6: 1.0: 0.2. All the galactose present in the purified mannan was accounted for as 2:3:4 :6- tetramethyl galactose.6. The 2:3 :4- trimethyl mannose fraction crystallised as a disaccharide, which was shown to be 1 -[ 2:3:4 -trimethyl D-mannopyranosido] - 2:3:4 -trimethyl D-mannopyranoside.7. The degree of polymerisation of the methylated mannan was determined by Barger's method and found to be 9 -11.8. Periodate oxidation experiments on the mannan showed that 1.6 moles of periodate were consumed per anhydrohexose unit, and one mole of formic acid was liberated per 4 anhydrohexose units.9. On the basis of these results possible structures for the mannan are proposed.Mannan B:1. Mannan B was extracted from the residue left after removal of mannan A from ivory nuts. The residue was extracted with cuprammonium hydroxide and the solution treated with sodium hydroxide. Several fractions were obtained and one which was considered to be mannan B was purified by dissolution in anhydrous formic acid and precipitation with ethanol.2. Purified mannan B gave on hydrolysis 98.3% mannose, 1.1% galactose, and 0.8% glucose.3 The reducing power of the mannan was determined by hypoiodite oxidation and colorimetrically by means of 3:5- dinitrosalicylic acid. The first method gave an apparent degree of polymerisation of 12, the second, 130. The values of the Chain length of mannan B obtained by these two methods were different and disagreed with the value obtained by other methods. Values of the chain length of the polysaccharide which are derived from measurement of the reducing power are, therefore, of doubtful validity.4. Mannan B was meth lated and the methylated polysaccharide hydrolysed. Separation of the mixture of sugars on a cellulose column gave 2:3:4:6 -tetramethyl D- mannose, 2:3 :4 :6- tetramethyl D- galactose, 2:3:6 -trimethyl D- mannose, 2:3:4 -trimethyl D- mannose, and 2:3- dimethyl D-mannose in the molar ratios of, respectively, 1 :1:63 :11 :1. All the galactose present in purified mannan B was accounted for as 2:3:4:6 -tetramethyl galactose.5. The 2 :3 :4- trimethyl mannose fraction crystallised as a disaccharide, which was shown to be 1 -[2 :3 :4- trimethyl D- mannopyranosido ] - 2:3:4- trimethyl D- mannopyranoside.6. The degree of polymerisation of methylated mannan B was determined by Barger's method and found to be 35-43.7. Periodate oxidation experiments on the mannan showed that 0.98 moles of periodate were consumed per anhydrohexose unit, and one mole of formic acid was liberated per 2.4 anhydrohexose units.8. On the basis of these results possible structures for the mannan are proposed