On Repairing Reasoning Reversals via Representational Refinements

Representation is a fluent. A mismatch between the real world and an agent’s representation of it can be signalled by unexpected failures (or successes) of the agent’s reasoning. The ‘real world ’ may include the ontologies of other agents. Such mismatches can be repaired by refining or abstracting an agent’s ontology. These refinements or abstractions may not be limited to changes of belief, but may also change the signature of the agent’s ontology. We describe the implementation and successful evaluation of these ideas in the ORS system. ORS diagnoses failures in plan execution and then repairs the faulty ontologies. Our automated approach to dynamic ontology repair has been designed specifically to address real issues in multi-agent systems, for instance, as envisaged in the Semantic Web

…and… between I and Thou: stretching metaxic space for children as seen from the perspective of my own spiritual journey

This thesis investigates the nature of children’s experience of solitude in the natural world (Magic Spots), during an earth education programme called EarthkeepersTM over a period of ten years at Ringsfield EcoCentre, Suffolk. It explores the practice of stretching metaxic space, that is the creative space inbetween one and another, to enable children to begin a way of learning which in turn will facilitate ways of being, or better, ways of becoming which can befriend the planet and not destroy it. The thesis is also the story of my own process required by the exploration. I have told this story through the lenses of hermeneutic-phenomenology and autoethnography while developing a diacritical hermeneutic of my own life and spiritual journey, which includes multiple ‘horizons’, in order to interpret the children’s responses. Finding the notion of the hermeneutical circle inadequate I have developed a dialectical hermeneutical, resonating and oscillating spiral, which demonstrates that in metaxic space children can be active agents in their own discovery and creation of self and meaning. Just like the developing children themselves, the process, the opportunities, and the space for the process are fragile and precious. It is easy to damage the spiral, thus the thesis also explores some implications for adults’ relationship with children. ‘…and…’ produces not conclusions but restless anticipations which are a contribution to the articulation of metaxic space in which children negotiate some meanings which have an adequate fit for a new way of being or way of becoming which suggest new directions for relationships with self, Others, the more-thanhuman- community and the cosmos. Keywords children, metaxic space, dialectic hermeneutics, hermeneutic spiral, relational consciousness, parenthesis, earth education, clowns. *[N.B.: Music files were attached to this thesis at the time of its submission. Please refer to the author for further details.

Beethoven’s Blue Remembered Hills

Various commentators have noted Beethoven’s use of a monotone in the second song of his cycle An die ferne Geliebte, where the repetition of a single note serves to conjure up the power of memory. This monotone served as a model for several subsequent composers of song cycles, often in a similar context when their singer/narrator recalls things that are past, from Peter Cornelius to Arnold Bax. In the case of Arthur Somervell’s A Shropshire Lad, a further correlation is found between his poet’s “blue-remembered hills” and Beethoven’s “Berge so blau”

Richard Wagner's Essays on Conducting

A new translation of Wagner's various essays on conducting with a critical commentary on their genesis, publication and reception

Synthetic strategies for 5- and 6-membered ring azaheterocycles facilitated by iminyl radicals

The author thanks EaStCHEM for financial support.The totality of chemical space is so immense that only a small fraction can ever be explored. Computational searching has indicated that bioactivity is associated with a comparatively small number of ring-containing structures. Pyrrole, indole, pyridine, quinoline, quinazoline and related 6-membered ring-containing aza-arenes figure prominently. This review focuses on the search for fast, efficient and environmentally friendly preparative methods for these rings with specific emphasis on iminyl radical mediated procedures. Oxime derivatives, particularly oxime esters and oxime ethers, are attractive precursors for these radicals. Their use is described in conventional thermolytic, microwave-assisted and UV-vis based preparative procedures. Photoredox catalyzed protocols involving designer oxime ethers are also covered. Choice can be made amongst these synthetic strategies for a wide variety of 5- and 6-membered ring heterocycles including phenanthridine and related aza-arenes. Applications to selected natural products and bioactive molecules including trispheridine, vasconine, luotonin A and rutaecarpine are included.Publisher PDFPeer reviewe

Microhydration and the enhanced acidity of free radicals

The author thanks EaStCHEM for financial support.Recent theoretical research employing a continuum solvent model predicted that radical centers would enhance the acidity (RED-shift) of certain proton-donor molecules. Microhydration studies employing a DFT method are reported here with the aim of establishing the effect of the solvent micro-structure on the acidity of radicals with and without RED-shifts. Microhydration cluster structures were obtained for carboxyl, carboxy-ethynyl, carboxy-methyl, and hydroperoxyl radicals. The numbers of water molecules needed to induce spontaneous ionization were determined. The hydration clusters formed primarily round the CO2 units of the carboxylate-containing radicals. Only 4 or 5 water molecules were needed to induce ionization of carboxyl and carboxy-ethynyl radicals, thus corroborating their large RED-shifts.Publisher PDFPeer reviewe

A bibliometric study of taxonomic botany

AIMS — The aims were: to investigate the citation-patterns of monograph books in taxonomic botany (looking mainly at publications and publishers, and the age of current literature); to provide information for collections management and reference services in libraries that hold botany materials. METHOD — 454 citations were collected from 47 botanical monographs; Impact Factors of journals based on these citations were calculated and compared with conventional Impact Factors from ISI Web of Science; age-distributions of citations were drawn up; other analyses were also carried out. RESULTS — A small Bradfordian core of highly-cited journals was established; monograph Impact Factors were not useable; the important publishers of monograph books were identified; monographs were more often cited than journal articles; older materials were more important than in other sciences; monographs were used by botanists for current awareness purposes; coverage of botanical journals by citation indexes was inadequate. CONCLUSIONS — Librarians should: note the core botanical journals identified here; note the importance of British journals to British botanists; continue to acquire botanical monographs and to retain older materials; display new botanical monographs prominently and include them in current awareness services. PROBLEMS — The small size of the sample means that results were merely indicative. Further studies should: take larger samples; look at citations in journal articles, theses, conference proceedings, etc.; look at citations made over several years. ORIGINALITY — The bibliometrics of taxonomic botany have previously been little studied; likewise citations from monographs. Some of the bibliometric methods of J. M. Cullars were applied to botanical literature

Optical and ion beam studies of excimer laser irradiated hexagonal silicon carbide

The realisation of doped regions, specifically Nitrogen, in Silicon Carbide (SiC) for transistor and p-n junction applications is a serious problem. Difficulty arises because of the low value of the diffusion coefficient and consequently the excessive temperatures required for substantial diffusion to take place can cause dissociation of the material. Coincidently, the robustness of Silicon Carbide makes it a suitable material for use in harsh environments, where excessive radiation and temperatures exist especially for high power and high frequency applications. Diffusion andactivation using thermal processes in equilibrium is not a practicable solution and therefore one feasible alternative technique is that of ion-implantation and laser annealing. However, the incorporation of dopants by ion implantation can cause damage to the crystal lattice. In the work that follows, excimer laser processing of Silicon Carbide has been employed to address these problems from two quite different approaches.Experimental investigations are carried out to investigate the laser interaction of Silicon Carbide over a range of laser fluence close to the ablation threshold. These experiments serve as preliminary investigations to establish the experimental process parameters for the fourth coming work. As a first approach, work was carried out in an attempt to introduce vacancy type defects into the lattice of 4H-SiC using both Argon Fluoride (193nm) and Xenon Chloride (308nm) excimer lasers, a technique we refer to here has "Laser Induced Defect Mediated Diffusion". The introduction of defects using ion beams to displace host atoms has previously been undertaken by other workers where it has been shown that the diffusion of dopant species can be enhanced, however, no such studies on Silicon Carbide exist at the present time using an excimer laser to specifically disrupt the lattice in this way. Photoluminescence (PL) and Positron Annihilation (PA) measurements are adopted as the diagnostic techniques to measure and quantify the response of Silicon Carbide subsequent to laser irradiation, hence help determine the nature of any defects that might have been introduced. PL measurements of ArF laser irradiated Silicon Carbide revealed the evolution of an emission band that correlates with the laser fluence which was tentatively associated with laser induced damage below the ablation threshold. Work is driven by these latter results and a technique for gaining further information on the nature of this band was adopted. The technique of PA is carried out on both ArF and XeCl laser irradiated material. On a microscopic scale the laser induced 'damage' consists of di-vacancy clusters at the near surface. The damage consists of large voids, essentially holes, which are not suitable for mediating the diffusion of dopant species in Silicon Carbide.Secondly, an alternative way of introducing Nitrogen dopants is carried out. Samples of 4H- and 6H-SiC were implanted with Nitrogen ions and later annealed using a Xenon Chloride excimer laser. The laser annealing experiments serve the purpose of removing/reducing implantation damage. Fourier Transform Infrared Reflection (FTIR) spectrometric and visible reflection measurements have been undertaken in an attempt to determine the optimum parameters for lattice recovery. We show that excimer laser annealing can be considered as an alternative method of removing ion-implantation damage when annealed at a optimum laser fluence and above this optimum the photon flux imparts detrimental damage to the lattice

EPR and pulsed ENDOR study of intermediates from reactions of aromatic azides with group 13 metal trichlorides

The reactions of group 13 metal trichlorides with aromatic azides were examined by CW EPR and pulsed ENDOR spectroscopies. Complex EPR spectra were obtained from reactions of aluminium, gallium and indium trichlorides with phenyl azides containing a variety of substituents. Analysis of the spectra showed that 4-methoxy-, 3-methoxy- and 2-methoxyphenyl azides all gave ‘dimer’ radical cations [ArNHC6H4NH2]+• and trimers [ArNHC6H4NHC6H4NH2]+• followed by polymers. 4-Azidobenzonitrile, with its electron-withdrawing substituent, did not react. In general the aromatic azides appeared to react most rapidly with AlCl3 but this reagent tended to generate much polymer. InCl3 was the least reactive group 13 halide. DFT computations of the radical cations provided corroborating evidence and suggested that the unpaired electrons were accommodated in extensive π-delocalised orbitals. A mechanism to account for the reductive conversion of aromatic azides to the corresponding anilines and thence to the dimers and trimers is proposedPublisher PDFPeer reviewe

Micro-machining of diamond, sapphire and fused silica glass using a pulsed nano-second Nd:YVO4 laser

Optically transparent materials are being found in an ever-increasing array of technological applications within industries, such as automotive and communications. These industries are beginning to realize the importance of implementing surface engineering techniques to enhance the surface properties of materials. On account of the importance of surface engineering, this paper details the use of a relatively inexpensive diode-pumped solid state (DPSS) Nd:YVO4 laser to modify the surfaces of fused silica glass, diamond, and sapphire on a micrometre scale. Using threshold fluence analysis, it was identified that, for this particular laser system, the threshold fluence for diamond and sapphire ranged between 10 Jcm−2 and 35 Jcm−2 for a laser wavelength of 355 nm, dependent on the cumulative effects arising from the number of incident pulses. Through optical microscopy and scanning electron microscopy, it was found that the quality of processing resulting from the Nd:YVO4 laser varied with each of the materials. For fused silica glass, considerable cracking and deformation occurred. For sapphire, good quality features were produced, albeit with the formation of debris, indicating the requirement for post-processing to remove the observed debris. The diamond material gave rise to the best quality results, with extremely well defined micrometre features and minimal debris formation, comparative to alternative techniques such as femtosecond laser surface engineering