Fenites associated with carbonatite complexes : a review

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Carbonatites and alkaline-silicate rocks are the most important sources of rare earth elements (REE) and niobium (Nb), both of which are metals imperative to technological advancement and associated with high risks of supply interruption. Cooling and crystallizing carbonatitic and alkaline melts expel multiple pulses of alkali-rich aqueous fluids which metasomatize the surrounding country rocks, forming fenites during a process called fenitization. These alkalis and volatiles are original constituents of the magma that are not recorded in the carbonatite rock, and therefore fenites should not be dismissed during the description of a carbonatite system. This paper reviews the existing literature, focusing on 17 worldwide carbonatite complexes whose attributes are used to discuss the main features and processes of fenitization. Although many attempts have been made in the literature to categorize and name fenites, it is recommended that the IUGS metamorphic nomenclature be used to describe predominant mineralogy and textures. Complexing anions greatly enhance the solubility of REE and Nb in these fenitizing fluids, mobilizing them into the surrounding country rock, and precipitating REE- and Nb-enriched micro-mineral assemblages. As such, fenites have significant potential to be used as an exploration tool to find mineralized intrusions in a similar way alteration patterns are used in other ore systems, such as porphyry copper deposits. Strong trends have been identified between the presence of more complex veining textures, mineralogy and brecciation in fenites with intermediate stage Nb-enriched and later stage REE enriched magmas. However, compiling this evidence has also highlighted large gaps in the literature relating to fenitization. These need to be addressed before fenite can be used as a comprehensive and effective exploration tool.This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 689909

Converging outcomes in nationally shareable electronic health records (NEHRs): An historical institutionalist explanation of similar NEHR outcomes in Australia, England and the United States of America

The adoption of nationally shareable electronic health records (NEHRs) in Australia, England and the United States became major policy and political issues between c1998 and 2015. They continue to be so. As a policy issue, the benefits of ehealth, and subsequently NEHRs as mechanisms for institutional change, were rhetorically popular. Politically however, the development, implementation and regulation of NEHRs proved to be difficult and fraught with criticism from nearly all ehealth stakeholders. The NEHR programs each country pursued at the national level were exceptionally expensive and complex infrastructure undertakings. They involved institutional change management that produced tension amongst stakeholders, required the state to decide on trade-offs that produced winners and losers, and resulted in unintended consequences. Initially, each country approached these policy and political issues differently. Examining why they then had substantially similar outcomes is the substantive puzzle that lies at the centre of this research. This thesis adopts an historical institutionalist approach to explain why state efforts to pursue the development, implementation and regulation of NEHRs at the national level in Australia, England and the United States resulted in substantially similar outcomes despite adopting initially different approaches. The thesis first compares why each case study country pursued ehealth, embarked on organisational change in order to achieve its ehealth and NEHR goals, and adopted NEHRs, noting similarities and major differences. The thesis then compares the state's role in the development of NEHRs at the national level in each country, again noting similarities and differences. A comparative evaluation of the cases is then undertaken in order to explain why each state continued to pursue NEHRs, despite the significant barriers to institutional change they faced. Here, the theoretical concepts of path dependency, critical junctures and incremental change are used to enhance the explanation. The thesis will then explain why the outcomes, as assessed through the lens of public policy evaluation, were substantially similar in each country. Finally, the thesis details the findings of the research through the lens of historical institutionalism and states the significance and implications of the research. The research found that while each case study country approached the policy and political issues of ehealth and NEHRs differently, the outcomes were substantially the same because their goals, and the barriers they faced in trying to achieve them, were very similar. Australia started with a decentralised national health information network (NHIN) then changed to a centralised NEHR. England started with, and continued to pursue, a centralised NEHR. The United States eschewed government development and implementation of an NEHR and took the path of incentivising and regulating electronic health records (EHRs) in an effort to make them nationally shareable. Similar goals across the three countries included moving from a paper to an EHR system; giving patients more control over their health information; making EHRs interoperable; increasing EHR usability and the meaningful use of patient health information; and improving the efficiency and effectiveness of care. Similar barriers included: cost, privacy, trust, stakeholder preferences, and the state attempting to drive change too quickly producing stakeholder resistance and negative outcomes. The thesis findings also provide support for theoretical explanations of institutional stasis and change within the context of path dependency, critical junctures and incremental institutional change

Precursor Synthesis and Chemical Vapour Deposition of Transition Metal Nitrides and Carbonitrides

This thesis is concerned with the chemical vapour deposition (CVD) of tungsten and zirconium nitride and carbonitride thin films. [W(μ-NtBu)(NtBu)Cl2(H2NtBu)]2, [W(NtBu)2Cl2(TMEDA)] (TMEDA = N,N,N’,N’-tetramethylethylenediamine) and [W(NtBu)2Cl2(py)2] (py = pyridine) have been investigated as potential precursors. Additionally, two novel precursors, [W(NtBu)2Cl{N(SiMe3)2}] and [W(NtBu)2(η5-Cp’)(η1-Cp’)] (Cp’ = methylcyclopentadienyl), have been synthesised via metathesis reactions of [W(NtBu)2Cl2(py)2] with the appropriate lithium or sodium amide salt. The attempted synthesis of [W(NtBu)2Cl{N(H)NMe2}] by lithium salt metathesis was unsuccessful due to polymerisation. Cyclopentadienyl-based precursors to zirconium carbonitride have been investigated, including [ZrCp2(NMe2)2], [ZrCp’2(NMe2)2] and four novel compounds: [ZrCp2(η2-MeNCH2CH2NMe)], [ZrCp’2(NEt2)2], [ZrCp’{(iPrN)2CNMe2}2Cl] and [ZrCp’2{(iPrN)2CNMe2}Cl] (Cp = 5-cyclopentadienyl, Cp’ = 5- methylcyclopentadienyl). The compounds were synthesised via sodium or lithium metathesis reactions. All compounds synthesised were characterised by NMR, mass spectrometry, elemental analysis and IR, and their decomposition was investigated by thermogravimetric analysis (TGA). The molecular structures of [ZrCp’{(iPrN)2CNMe2}2Cl] and [ZrCp’2{(iPrN)2CNMe2}Cl] were determined by single crystal X-ray diffraction. Thin films of tungsten carbonitride, zirconium carbide and zirconium carbonitride were deposited by low pressure CVD (LPCVD) at 550-600 °C and 0.1 Torr using the aforementioned precursors. In addition, aerosol-assisted CVD (AACVD) of [W(μ-NtBu)(NtBu)Cl2(H2NtBu)]2 in toluene was investigated as a comparison. All films deposited via CVD were characterised using wavelength dispersive X-ray spectroscopy (WDX), glancing-angle XRD, UV/Vis spectroscopy (for reflectance and transmission measurements) and their morphology and thickness were investigated using SEM imaging. Plasma-enhanced atomic layer deposition (PEALD) using [ZrCp2(NMe2)2] and [ZrCp2(η2-MeNCH2CH2NMe)] was studied with the view to depositing stoichiometric ZrN. It showed these precursors to be insufficiently volatile for the ALD system as the growth rates were low. The ALD progress was analysed using in situ ellipsometry and mass spectrometry

Effects of pile driving sound playbacks and cadmium co-exposure on the early life stage development of the Norway lobster, Nephrops norvegicus

There is an urgent need to understand how organisms respond to multiple, potentially interacting drivers in today’s world. The effects of the pollutants of anthropogenic sound (pile-driving sound playbacks) and waterborne cadmium were investigated across multiple levels of biology in larvae of the Norway lobster, Nephrops norvegicus under controlled laboratory conditions. The combination of pile-driving playbacks (170 dBpk-pk re 1 µPa) and cadmium combined synergistically at concentrations > 9.62 µg[Cd] L-1, resulting in increased larval mortality, with sound playbacks otherwise antagonistic to cadmium toxicity. Significant delays in larval development were caused by exposure to 63.52 µg[Cd] L-1, dropping to 6.48 µg[Cd] L-1 in the presence of piling playbacks. Pre-exposure to piling playbacks and 6.48 µg[Cd] L-1 led to significant differences in swimming behaviour of the first juvenile stage. Biomarker analysis suggested oxidative stress as the mechanism of deleterious effects, with cellular metallothionein (MT) being the predominant protective mechanism

PSO-based coevolutionary Game Learning

Games have been investigated as computationally complex problems since the inception of artificial intelligence in the 1950’s. Originally, search-based techniques were applied to create a competent (and sometimes even expert) game player. The search-based techniques, such as game trees, made use of human-defined knowledge to evaluate the current game state and recommend the best move to make next. Recent research has shown that neural networks can be evolved as game state evaluators, thereby removing the human intelligence factor completely. This study builds on the initial research that made use of evolutionary programming to evolve neural networks in the game learning domain. Particle Swarm Optimisation (PSO) is applied inside a coevolutionary training environment to evolve the weights of the neural network. The training technique is applied to both the zero sum and non-zero sum game domains, with specific application to Tic-Tac-Toe, Checkers and the Iterated Prisoners Dilemma (IPD). The influence of the various PSO parameters on playing performance are experimentally examined, and the overall performance of three different neighbourhood information sharing structures compared. A new coevolutionary scoring scheme and particle dispersement operator are defined, inspired by Formula One Grand Prix racing. Finally, the PSO is applied in three novel ways to evolve strategies for the IPD – the first application of its kind in the PSO field. The PSO-based coevolutionary learning technique described and examined in this study shows promise in evolving intelligent evaluators for the aforementioned games, and further study will be conducted to analyse its scalability to larger search spaces and games of varying complexity.Dissertation (MSc)--University of Pretoria, 2005.Computer Scienceunrestricte

Compliance framework for change management in cloud environments

Mención Internacional en el título de doctorThe Governance, Risk and Compliance (GRC) area is one of the critical management areas for every organization. This is particularly the case for information technology (IT) departments where both human resources and technical infrastructures (software and hardware) need to work seamlessly in order to provide the expected benefits. The study of the literature shows that sound GRC methods are key to running and maintaining secure and compliant computing infrastructures. An important and particularly challenging aspect of the IT landscape is its constant and perpetual evolution in order to keep pace with new and emerging technologies that find their way faster and faster into the organizational infrastructure. Since assessments of risks and compliance aspects always refer to a certain (more or less static) situation, such frequent changes pose a real danger to the overall relevance of these assessments in the mid and longterm perspective. So, a sound approach to ensuring compliance not only punctually (both in time and space) but holistically – considering the complete IT landscape in a continuous way – needs to integrate with the change management function of the organization. Another important development in the last eight to ten years was the emergence of Cloud Computing (CC) as a straightforward and efficient way of providing IT functionality to organizations. While it poses many various challenges to IT management in general, CC is particularly relevant for GRC as it makes an IT provision approach that was previously sometimes applied – outsourcing – to a predominant approach to provide infrastructure (called Infrastructure‐as‐a‐Service or IaaS), platforms (called Platform‐as‐a‐Service or PaaS), and software (called Software‐as‐a‐Service or SaaS) within an organization. CC and outsourcing entail wider challenges for GRC as it involves the inclusion of an external party as a service provider within an organization reflecting specific aspects of provider selection, contract management, service level agreements (SLAs), and monitoring. They become even more challenging in the context of frequent and interdependent changes. Therefore, this thesis is aimed at the definition and validation of a Compliance Framework for Change Management in Cloud Environments (short: CFC MCC). The proposed solution of the problem has been approached from a multidisciplinary point of view taking in consideration aspects from computer science, IT management and IT governance, but also such aspects as legal and cultural dimensions. The proposed solution provides a framework to support the solicitation of requirements from different subject areas (e.g., organizational, technological, cultural) and their subsequent consideration within the change management process of established IT management frameworks such as ITIL. It can be tailored to the specific situation of most organizations and provides a consistent approach to address GRC aspects in rapidly evolving cloud‐based organizational IT landscapes. The scientific discourse within the thesis has been structured following best academic practices and recommendations. In the last phase of the research methodology an empirical validation has been performed to verify the applicability of the framework. The data obtained from the validation indicate that the application of the framework for ensuring compliance in CC environments constitutes a relevant improvement of the change management process.El área de gobernanza, riesgo y cumplimiento (por sus siglas en inglés GRC) es una de las áreas de gestión clave en todas las organizaciones. En el caso de los departamentos de Tecnología de la Información (por sus siglas en inglés IT de Information Technology) el área cuenta con una importancia igualmente crucial. Estos departamentos deben orquestar los recursos de capital intelectual y las infraestructuras hardware y software para contribuir a la generación de beneficios empresariales. La literatura ha demostrado que un conjunto de procedimientos en el área GRC es clave para prestar el servicio de forma eficiente a partir del mantenimiento de una infraestructura tecnológica segura y compatible. Un aspecto importante y particularmente retador en el entorno IT es su constante evolución con el propósito de habilitar la adopción de nuevas tecnologías en apoyo de los procesos corporativos. Dado que la evaluación de riesgos y los aspectos de cumplimiento se refieren a una determinada situación que se puede considerar más o menos estática, los continuos cambios en el entorno IT representan una amenaza para la incorporación de nuevas tecnologías en ámbitos corporativos desde el punto de vista GRC. Por ello, un enfoque sólido para garantizar el cumplimiento no sólo de forma puntual en tiempo y espacio sino de forma integral, considerando el entorno IT en una forma continua e integrada con la gestión del cambio corporativa. Otro desarrollo importante y modificador de la situación actual es la emergencia de la computación en la nube (CC, siglas en inglés de Cloud Computing) como una forma efectiva y eficaz de proporcionar la función IT en las organizaciones. Pese a que CC suscita diversos desafíos para la administración IT, es en particular relevante para GRC ya que habilita la externalización del servicio como una aproximación predominante para proporcionar infraestructura (llamado Infraestructure‐as‐a‐Service o IaaS), plataformas (llamado Platformas‐ a‐Service o PaaS) y software (llamado Software‐as‐a‐Service o SaaS) dentro de una organización. CC y la externalización suponen retos más amplios para GRC, ya que implican la inclusión de un proveedor de servicios externo dentro de una organización. Esta circunstancia aflora cuestiones relativas a la selección de proveedores, la gestión de contratos, los acuerdos de nivel de servicio (por sus siglas en inglés SLA), y el seguimiento de las relaciones y los servicios prestados. Estos aspectos, se convierten en un reto aún mayor en el contexto de los cambios frecuentes e interdependientes en el ámbito IT. Por lo tanto, esta tesis está dirigida a la definición y validación de un marco de cumplimiento para la gestión del cambio en entornos relativos a la nube (abreviatura: CFC MCC). La solución propuesta del problema ha sido abordada desde un punto de vista multidisciplinar, tomando en consideración aspectos de la informática, la gestión de IT y el gobierno de IT pero incorporando también aspectos tales como las dimensiones legales y culturales. La solución propuesta proporciona un marco para apoyar la solicitud de requisitos de diferentes áreas (por ejemplo, organizativos, tecnológicos, culturales) y su posterior consideración en el proceso de gestión del cambio de los marcos establecidos de gestión de TI como pueda ser ITIL. EL marco puede ser adaptado a la situación específica de las organizaciones y proporciona un enfoque coherente para abordar los aspectos de GRC en rápida evolución entornos de TI de la organización basados en la nube. El discurso científico dentro de la tesis se ha estructurado siguiendo las prácticas académicas y recomendaciones de investigación. En la última fase de la metodología de la investigación empírica una validación se ha realizado para verificar la aplicabilidad del marco. Los datos obtenidos de la validación indican que la aplicación del marco para garantizar el cumplimiento en entornos CC constituye una mejora relevante del proceso de gestión del cambio de las organizaciones.Programa Oficial de Doctorado en Ciencia y Tecnología InformáticaPresidente: Antonio de Amescua Seco.- Secretario: José Antonio Manzano Calvo.- Vocal: Ahmed Barnaw

Clinopyroxene/melt trace element partitioning in sodic alkaline magmas

Clinopyroxene is a key fractionating phase in alkaline magmatic systems, but its impact on metal enrichment processes, and the formation of REE + HFSE mineralisation in particular, is not well understood. To constrain the control of clinopyroxene on REE + HFSE behaviour in sodic (per)alkaline magmas, a series of internally heated pressure vessel experiments was performed to determine clinopyroxene–melt element partitioning systematics. Synthetic tephriphonolite to phonolite compositions were run H2O-saturated at 200 MPa, 650–825°C with oxygen fugacity buffered to log f O2 ≈ ΔFMQ + 1 or log f O2 ≈ ΔFMQ +5. Clinopyroxene–glass pairs from basanitic to phonolitic fall deposits from Tenerife, Canary Islands, were also measured to complement our experimentally-derived data set. The REE partition coefficients are 0·3–53, typically 2–6, with minima for high-aegirine clinopyroxene. Diopside-rich clinopyroxene (Aeg5–25) prefer the MREE and have high REE partition coefficients (DEu up to 53, DSm up to 47). As clinopyroxene becomes more Na- and less Ca-rich (Aeg25–50), REE incorporation becomes less favourable, and both the VIM1 and VIIIM2 sites expand (to 0·79 Å and 1·12 Å), increasing DLREE/DMREE. Above Aeg50 both M sites shrink slightly and HREE (VIri ≤ 0·9 Å ≈ Y) partition strongly onto the VIM1 site, consistent with a reduced charge penalty for REE3+ ↔ Fe3+ substitution. Our data, complemented with an extensive literature database, constrain an empirical model that predicts trace element partition coefficients between clinopyroxene and silicate melt using only mineral major element compositions, temperature and pressure as input. The model is calibrated for use over a wide compositional range and can be used to interrogate clinopyroxene from a variety of natural systems to determine the trace element concentrations in their source melts, or to forward model the trace element evolution of tholeiitic mafic to evolved peralkaline magmatic systems

A novel computer Scrabble engine based on probability that performs at championship leve

The thesis starts by giving an introduction to the game of Scrabble, then mentions state-of-the-art computer Scrabble programs and presents some characteristics of our developed Scrabble engine Heuri. Some brief notions of Game Theory are given, along with history of some games in Artificial Intelligence; the fundamental algorithms for game playing, as well as state-of-the-art engines and the algorithms used by them, are presented. Basic elements of Scrabble, such as the Scrabble rules and the letter distribution, are given. Some history and state-of-the-art of Computer Scrabble are commented. For instance, the generation methods of valid moves based on the data structure DAWG (Directed Acyclic Word Graph) and also the variant GADDAG are recalled. These methods are used by the state-of-the-art Scrabble engines Quackle and Maven. Then, the contributions of this thesis are presented. A Spanish lexicon for playing Scrabble has been built that is used by Heuri engines. From this construction, a detailed study and classification of Spanish irregular verbs has been provided. A novel Scrabble move generator based on anagrams has been designed and implemented, which has been shown to be faster than the GADDAG-based generator used in Quackle engine. This method is similar to the way Scrabble players look for a move, searching for anagrams and a spot to play on the board. Next, we address the evaluation of moves when playing Scrabble; the quality of your game depends on deciding what move should be played given a certain board and a rack with tiles. This decision was made initially by Heuri trying several heuristics which ended up with the construction of several engines. We give the explanation of the heuristics used in these engines, all of them based on probabilities. All these initial heuristic evaluation functions (up to six) do not use forward looking, they are static evaluators. They have shown, after testing, an increasing playing performance, which allow Heuri to beat (top-level) expert human players in Spanish, without the need of using sampling and simulation techniques. These heuristics mainly consider the possibility of achieving a bingo on the actual board, whereas Quackle used pre-calculated values (superleaves) regardless of the latter. Then, in order to improve the quality of play of Heuri even more, some additional engines are presented in which look ahead is employed. The HeuriSamp engine, which evaluates a 2-ply search, permits to obtain a defense value. The HeuriSim engine uses a 3-ply adversarial search tree; it contemplates the best first moves (according to Heuri sixth engine heuristic) from Player 1, then some replies to these moves (Player 2 moves) and then some replies to these replies (Player 1 moves). Finally, to improve these engines, opponent modeling is used; this technique makes predictions on some of the opponents' tiles based on the last play made by the opponent. We present results obtained by playing thousands of Heuri vs Heuri games, collecting important information: general statistics of Scrabble game, like a 16 point handicap of the second player, and word statistics in Spanish, like a list of the most frequently played bingos (words that use all 7 tiles of a player's rack). In addition, we present results of matches played by Heuri against top-level humans in Spanish and results obtained by massive playing of different Heuri engines against the Quackle engine in Spanish, French and English. All these match results demonstrate the championship level performance of the Heuri engines in the three languages, especially of the last developed engine that includes simulation and opponent modeling techniques. From here, conclusions of the thesis are drawn and work for the future is envisaged.La tesi comença introduint el joc del Scrabble, esmentant els programes d’ordinador de l’estat de l’art que juguen Scrabble, i presentant algunes característiques del motor de joc de Scrabble que s’ha desenvolupat anomenat Heuri. Es donen breus nocions de la Teoria de Jocs, junt amb la història d’alguns jocs en Intel·ligència Artificial; es presenten els algorismes fonamentals per jugar, així com els motors de joc de l’estat de l’art en diferents jocs i els algorismes que usen. Es comenta també la història i estat de l’art del Computer Scrabble. Es recorden els mètodes de generació de moviments vàlids basats en l’estructura de dades DAWG (Directed Acyclic Word Graph) i en la variant GADDAG, que són usats pels motors de joc de Scrabble Quackle i Maven. A continuació es presenten les contribucions de la tesi. S’ha construït un diccionari per jugar Scrabble en espanyol, el qual és usat per les diferentes versions del motor de joc Heuri. S’ha fet un estudi detallat i una classificació dels verbs irregulars en espanyol. S’ha dissenyat i implementat un nou generador de moviments de Scrabble basat en anagrames, que ha demostrat ser més ràpid que el generador basat en GADDAG usat al motor Quackle. Aquest mètode és similar a la manera en la que els jugadors de Scrabble cerquen un moviment, buscant anagrames i un lloc del tauler on col·locar-los. Seguidament, es tracta l’evacuació dels moviments quan es juga Scrabble; la qualitat del joc depèn de decidir quin moviment cal jugar donat un cert tauler i un faristol amb fitxes. En Heuri, inicialment, aquesta decisió es va prendre provant diferents heurístiques que van dur a la construcció de diversos motors. Donem l’explicació de les heurístiques usades en aquests motors, totes elles basades en probabilitats. Totes aquestes funcions d’avaluació heurística inicials (fins a sis) no miren cap endavant, fan avaluacions estàtiques. Han mostrat, després de ser provades, un rendiment creixent de nivell de joc, el que ha permès Heuri derrotar a jugadors humans experts de màxim nivell en espanyol, sense necessitat d’usar tècniques de mostreig i de simulació. Aquestes heurístiques consideren principalment la possibilitat d’aconseguir un bingo en el tauler actual, mentre que Quackle usa uns valors pre-calculats (superleaves) que no tenen en compte l’anterior. Amb l’objectiu de millorar la qualitat de joc de Heuri encara més, es presenten uns motors de joc addicionals que sí miren cap endavant. El motor HeuriSamp, que realitza una cerca 2-ply, permet obtenir un valor de defensa. El motor HeuriSim usa un arbre de cerca 3-ply; contempla els millors primers moviments (d’acord al sisè motor heurístic d’Heuri) del Jugador 1, després algunes respostes a aquests moviments (moviments del Jugador 2) i llavors algunes rèpliques a aquestes respostes (moviments del Jugador 1). Finalment, per a millorar aquests motors, es proposa usar modelatge d’oponents; aquesta tècnica realitza prediccions d’algunes de les fitxes de l’oponent basant-se en l’últim moviment jugat per aquest. Es presenten resultats obtinguts de jugar milers de partides d’Heuri contra Heuri, que recullen important informació: estadístiques generals del joc del Scrabble, com un handicap de 16 punts del segon jugador, i estadístiques de paraules en espanyol, com una llista dels bingos (paraules que usen les 7 fitxes del faristol d’un jugador) que es juguen més freqüentment. A més, es presenten resultats de partides jugades per Heuri contra jugadors humans de màxim nivell en espanyol i resultats obtinguts d'un gran nombre d’enfrontaments entre els diferents motors de joc d’Heuri contra el motor Quackle en espanyol, francès i anglès. Tots aquests resultats de partides jugades demostren el rendiment de nivell de campió dels motors d’Heuri en les tres llengües, especialment el de l’últim motor desenvolupat que inclou tècniques de de simulació i modelatge d'oponents. A partir d'aquí s'extreuen les conclusions de la tesi i es preveu treballar de cara al futur.Postprint (published version