281 research outputs found

    The role of the planner in recovery after disaster: A case study of the Canterbury Earthquake Recovery Act 2011 and its impact on planners operating in post-quake Christchurch : A dissertation submitted in partial fulfilment of the requirements for the degree of Master of Planning

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    The world experiences a number of disasters each year. Following a disaster, the affected area moves to a phase of recovery which involves multiple stakeholders. An important element of recovery is planning the rebuild of the affected environment guided by the legislative framework to which planning is bound to (March & Kornakova, 2017). Yet, there appears to be little research that has investigated the role of planners in a recovery setting and the implications of recovery legislative planning frameworks. This study was conducted to explore the role of the planner in the Canterbury earthquake recovery process in New Zealand and the impact of the Canterbury Earthquake Recovery Act 2011 (CER Act) on planners’ roles and how they operated. The methodology comprised a combination of document analysis of legislation and related recovery material and 21 semi-structured interviews with key planners, politicians and professionals involved in the recovery. The results suggest that the majority of planners interviewed were affected by the CER Act in their role and how they operated, although institutional context, especially political constraints, was a key factor in determining the degree of impact. It is argued that planners played a key role in recovery and were generally equipped in terms of skills needed in a recovery setting. In order to better utilise planners in post-disaster recovery or disaster risk management, two suggestions are proposed. Firstly, better promote planners and their capabilities to improve awareness of what planners can do. Secondly, educate and build an understanding between central government politicians and planners over each others role to produce better planning outcomes

    Computational studies into the rhodium catalysed dehydrocoupling of amine- and phosphine-boranes

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    This thesis details the use of density functional theory to study the mechanisms of dehydrocoupling of amine- and phosphine-boranes using a variety of Rh catalysts in collaboration with the group of Professor Andrew Weller at the University of Oxford. The dehydrocoupling of phosphine-boranes with pre-catalysts [Rh(Ph2P(CH2)2(PPh2)(η6-C6H5F)]+ (Chapter 3) and [Rh(Me)(CH2Cl2)(PMe3)(η5-Cp*)]+ (Chapter 4) were studied. For [Rh(Ph2P(CH2)2(PPh2)(η6-C6H5F)] + the computed mechanism involves facile P-H activation, B-H activation and a rate-limiting B-P coupling process. A functional and basis set study was conducted to benchmark against experimental activation parameters. Furthermore, the differences in reaction of pre-catalyst [Rh(Me)(CH2Cl2)(PMe3)(η5-Cp*)]+ with H3B-PPh2H and H3BPtBu2H, which yield [Rh(PMe3)(η5-Cp*)(PPh2BH3)]+ and [Rh(H)(η5-Cp*)(PtBu2BH2PMe3)]+ respectively were rationalised computationally. The dehydropolymerisation of monomethylamine-borane H3B-NMeH2 using a range of alkylXantphos Rh catalysts: neutral [Rh(mer-κ3-P,O,P-Xantphos-iPr)H], and [Rh(mer-κ3-P,O,PXantphos-tBu)H], and cationic [Rh(mer-κ3-P,O,P-Xantphos-iPr)(H)2(η1-H3B-NMeH2)]+, and [Rh(mer-κ3-P,O,P-Xantphos-tBu)H2]+ is discussed in Chapter 5. The neutral catalysts were found to proceed via different outer-sphere dehydrogenation pathways. [Rh(mer-κ3-P,O,P-XantphosiPr)H] forms free H2B=NMeH and a tri-hydride intermediate while [Rh(mer-κ3-P,O,P-XantphostBu)H] proceeds through a novel process to form free H2B=NMeH, H2 and regenerate the catalyst in one step. A head-to-tail propagation mechanism would then form polyamino-borane [H2BNMeH]n. Dehydropolymerisation mechanisms have also been explored for the cationic catalysts with [Rh(mer-κ3-P,O,P-Xantphos-tBu)H2]+ being postulated to follow a dehydrogenation mechanism involving the formation of boronium cations [(NMeH2)2BH2]+. In Chapter 6 a study of the electronic structure and bonding of boron-containing Rh-dimers [{Rh(dipp)}2(H)(BH2NH2)]+, [{RhH}2(μ-BNMe2)(μ-dpcm)2(μ-H)]+, and [{Rh(κ3-P,O,P-XantphosiPr)}2B]+ was conducted. All of these species are formed during amine-borane dehydrocoupling catalysis

    Regional cerebral metabolic patterns demonstrate the role of anterior forebrain mesocircuit dysfunction in the severely injured brain

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    peer reviewedAlthough disorders of consciousness (DOCs) demonstrate widely varying clinical presentations and patterns of structural injury, global down-regulation and bilateral reductions in metabolism of the thalamus and frontoparietal network are consistent findings. We test the hypothesis that global reductions of background synaptic activity in DOCs will associate with changes in the pattern of metabolic activity in the central thalamus and globus pallidus. We compared 32 [18F]fluorodeoxyglucose PETs obtained from severely brain-injured patients (BIs) and 10 normal volunteers (NVs). We defined components of the anterior forebrain mesocircuit on high-resolution T1-MRI (ventral, associative, and sensorimotor striatum; globus pallidus; central thalamus and noncentral thalamus). Metabolic profiles for BI and NV demonstrated distinct changes in the pattern of uptake: ventral and association striatum (but not sensorimotor) were significantly reduced relative to global mean uptake after BI; a relative increase in globus pallidus metabolism was evident in BI subjects who also showed a relative reduction of metabolism in the central thalamus. The reversal of globus pallidus and central thalamus profiles across BIs and NVs supports the mesocircuit hypothesis that broad functional (or anatomic) deafferentation may combine to reduce central thalamus activity and release globus pallidus activity in DOCs. In addition, BI subjects showed broad frontoparietal metabolic down-regulation consistent with prior studies supporting the link between central thalamic/pallidal metabolism and down-regulation of the frontoparietal network. Recovery of left hemisphere frontoparietal metabolic activity was further associated with command following

    Unexpected Vulnerability of DPEphos to C-O Activation in the Presence of Nucleophilic Metal Hydrides

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    C−O bond activation of DPEphos occurs upon mild heating in the presence of [Ru(NHC)2(PPh3)2H2] (NHC=N-heterocyclic carbene) to form phosphinophenolate products. When NHC=IEt2Me2, C−O activation is accompanied by C−N activation of an NHC ligand to yield a coordinated N-phosphino-functionalised carbene. DFT calculations define a nucleophilic mechanism in which a hydride ligand attacks the aryl carbon of the DPEphos C−O bond. This is promoted by the strongly donating NHC ligands which render a trans dihydride intermediate featuring highly nucleophilic hydride ligands accessible. C−O bond activation also occurs upon heating cis-[Ru(DPEphos)2H2]. DFT calculations suggest this reaction is promoted by the steric encumbrance associated with two bulky DPEphos ligands. Our observations that facile degradation of the DPEphos ligand via C−O bond activation is possible under relatively mild reaction conditions has potential ramifications for the use of this ligand in high-temperature catalysis.</p

    Availability, outage, and capacity of spatially correlated, Australasian free-space optical networks

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    Network capacity and reliability for free space optical communication (FSOC) is strongly driven by ground station availability, dominated by local cloud cover causing an outage, and how availability relations between stations produce network diversity. We combine remote sensing data and novel methods to provide a generalised framework for assessing and optimising optical ground station networks. This work is guided by an example network of eight Australian and New Zealand optical communication ground stations which would span approximately 60∘60^\circ in longitude and 20∘20^\circ in latitude. Utilising time-dependent cloud cover data from five satellites, we present a detailed analysis determining the availability and diversity of the network, finding the Australasian region is well-suited for an optical network with a 69% average site availability and low spatial cloud cover correlations. Employing methods from computational neuroscience, we provide a Monte Carlo method for sampling the joint probability distribution of site availabilities for an arbitrarily sized and point-wise correlated network of ground stations. Furthermore, we develop a general heuristic for site selection under availability and correlation optimisations, and combine this with orbital propagation simulations to compare the data capacity between optimised networks and the example network. We show that the example network may be capable of providing tens of terabits per day to a LEO satellite, and up to 99.97% reliability to GEO satellites. We therefore use the Australasian region to demonstrate novel, generalised tools for assessing and optimising FSOC ground station networks, and additionally, the suitability of the region for hosting such a network.Comment: Accepted in Journal of Optical Communications and Networking. 16 pages, 16 figure

    Dehydropolymerization of H3B·NMeH2 Using a [Rh(DPEphos)]+ Catalyst : The Promoting Effect of NMeH2

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    [Rh(κ2-PP-DPEphos){η2η2-H2B(NMe3)(CH2)2tBu}][BArF4] acts as an effective precatalyst for the dehydropolymerization of H3B·NMeH2 to form N-methylpolyaminoborane (H2BNMeH)n. Control of polymer molecular weight is achieved by variation of precatalyst loading (0.1-1 mol %, an inverse relationship) and use of the chain-modifying agent H2: with Mn ranging between 5 500 and 34 900 g/mol and between 1.5 and 1.8. H2 evolution studies (1,2-F2C6H4 solvent) reveal an induction period that gets longer with higher precatalyst loading and complex kinetics with a noninteger order in [Rh]TOTAL. Speciation studies at 10 mol % indicate the initial formation of the amino-borane bridged dimer, [Rh2(κ2-PP-DPEphos)2(μ-H)(μ-H2BN=HMe)][BArF4], followed by the crystallographically characterized amidodiboryl complex [Rh2(cis-κ2-PP-DPEphos)2(σ,μ-(H2B)2NHMe)][BArF4]. Adding ∼2 equiv of NMeH2 in tetrahydrofuran (THF) solution to the precatalyst removes this induction period, pseudo-first-order kinetics are observed, a half-order relationship to [Rh]TOTAL is revealed with regard to dehydrogenation, and polymer molecular weights are increased (e.g., Mn = 40 000 g/mol). Speciation studies suggest that NMeH2 acts to form the precatalysts [Rh(κ2-DPEphos)(NMeH2)2][BArF4] and [Rh(κ2-DPEphos)(H)2(NMeH2)2][BArF4], which were independently synthesized and shown to follow very similar dehydrogenation kinetics, and produce polymers of molecular weight comparable with [Rh(κ2-PP-DPEphos){ η2-H2B(NMe3)(CH2)2tBu}][BArF4], which has been doped with amine. This promoting effect of added amine in situ is shown to be general in other cationic Rh-based systems, and possible mechanistic scenarios are discussed

    Synthesis of Functionalized 1,4-Azaborinines by the Cyclization of Di-tert-butyliminoborane and Alkynes

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    Di-tert-butyliminoborane is found to be a very useful synthon for the synthesis of a variety of functionalized 1,4-azaborinines by the Rh-mediated cyclization of iminoboranes with alkynes. The reactions proceed via [2 + 2] cycloaddition of iminoboranes and alkynes in the presence of [RhCl(PiPr3)2]2, which gives a rhodium η4-1,2-azaborete complex that yields 1,4-azaborinines upon reaction with acetylene. This reaction is compatible with substrates containing more than one alkynyl unit, cleanly affording compounds containing multiple 1,4-azaborinines. The substitution of terminal alkynes for acetylene also led to 1,4-azaborinines, enabling ring substitution at a predetermined location. We report the first general synthesis of this new methodology, which provides highly regioselective access to valuable 1,4-azaborinines in moderate yields. A mechanistic rationale for this reaction is supported by DFT calculations, which show the observed regioselectivity to arise from steric effects in the B-C bond coupling en route to the rhodium η4-1,2-azaborete complex and the selective oxidative cleavage of the B-N bond of the 1,2-azaborete ligand in its subsequent reaction with acetylene.</p

    ‘Scots and Scabs from North-by-Tweed’:Undesirable Scottish Migrants in Seventeenth- and Early Eighteenth-Century England

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    While very prominent in the contemporary world, anxiety about the potentially negative impact that immigrants might have on their host communities has deep historical roots. In a British context, such fears were particularly heightened following the regal union of 1603 when large numbers of Scots began settling in England. This article offers a fresh perspective on these issues by exploring the experiences and reception of poor, deviant or otherwise ‘undesirable’ Scottish migrants to England during the seventeenth and eighteenth centuries. Focusing in particular on chapmen, vagrants and criminals, it suggests that, while in general Scots were able to integrate relatively easily into English society, there existed an unwelcome subset surviving by dubious means. Though not usually attracting unduly severe treatment on account of their nationality, these unwelcome migrants had a disproportionate effect on English perceptions of and attitudes towards the broader cohort of Scottish migrants in their midst
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