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Alvin, Yeoh Chong Yeow. "Nucleation of polymorphic forms." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498979.
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In this PhD project, the solvent effects on polymorphism were studied. This was done using an enantiotropic compound. By working at the transition temperature of the compound, it allowed for the separation of supersaturation effects from that of the solvent. p-Aminobenzoic acid was chosen as the model compound. p-Aminobenzoic acid (PABA) is an enantiotropic compound with a transitior temperature of 24°C. It has two polymorphs, a needle shaped α-form which is stable above the transition temperature and a prismatic shaped β-form stable below the transition temperature.
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Wansbrough, Keith Stuart. "Simple polymorphic usage analysis." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619586.
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Yang, Jun. "Improving polymorphic type explanations." Thesis, Heriot-Watt University, 2001. http://hdl.handle.net/10399/509.
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Towler, Christopher. "Nucleation in polymorphic systems." Thesis, University of Manchester, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520283.
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Mathieson, John T. J. "Towards Polymorphic Systems Engineering." Thesis, The George Washington University, 2021. http://pqdtopen.proquest.com/#viewpdf?dispub=28257912.
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Systems engineering is widely regarded as a full life cycle discipline and provides methodologies and processes to support the design, development, verification, sustainment, and disposal of systems. While this cradle-to-grave concept is well documented throughout literature, there has been recent and ever-increasing emphasis on evolving and digitally transforming systems engineering methodologies, practices, and tools to a model-based discipline, not only for advancing system development, but perhaps more importantly for extending agility and adaptability through the later stages of system life cycles – through system operations and sustainment. This research adopts principles from the software engineering domain DevOps concept (a collaborative merger of system development and system operations) into a Systems Engineering DevOps Lemniscate life cycle model. This progression on traditional life cycle models lays a foundation for the continuum of model-based systems engineering artifacts during the life of a system and promotes the coexistence and symbiosis of variants throughout. This is done by facilitating a merger of model-based systems engineering processes, tools, and products into a surrogate and common modeling environment in which the operations and sustainment of a system is tied closely to the curation of a descriptive system model. This model-based approach using descriptive system models, traditionally leveraged for system development, is now expanded to include the operational support elements necessary to operate and sustain the system (i.e. executable procedures, command scripts, maintenance manuals, etc. modeled as part of the core system). This evolution on traditional systems engineering implementation, focused on digitally transforming and enhancing system operations and sustainment, capitalizes on the ability of model-based systems engineering to embrace change to improve agility in the later life cycle stages and emphasizes the existence of polymorphic systems engineering (performing a variety of systems engineering roles in simultaneously occurring life cycle stages to increase system agility). A model-based framework for applying the Systems Engineering DevOps life cycle model is introduced as a new Systems Modeling Language profile. A use-case leveraging this “Model-Based System Operations” framework demonstrates how merging operational support elements into a spacecraft system model improves adaptability of support elements in response to faults, failures, and evolving environments during system operations, exemplifying elements of a DevOps approach to cyber-physical system sustainment.
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Strege, Christine. "On (pseudo- ) polymorphic phase transformations." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974120006.
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Dharmayat, Spoorthi. "Polymorphic transformation of pharmaceutical compounds." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507688.
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Pantazis, Dimitrios A. "Electronic structure of polymorphic complexes." Thesis, University of York, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440979.
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MacSweeney, Siobhan. "An examination of the polymorphic and pseudo-polymorphic behaviour of fluconazole in relation to processing conditions." Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/1253.
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Schonhoft, Joseph. "Biochemical and Biophysical Study of the Polymorphic G-Quadruplexes Formed by the Insulin Linked Polymorphic Region." Kent State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=kent1248116483.
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Bonem, Peter Bryant. "Towards an implementation of Polymorphic C." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA305190.
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Laverman, Bert. "Supporting software reusability with polymorphic types." [S.l. : [Groningen] : s.n.] ; [University Library Groningen] [Host], 1995. http://irs.ub.rug.nl/ppn/137162723.
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Tofte, Mads. "Operational semantics and polymorphic type inference." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/6606.
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Three languages with polymorphic type disciplines are discussed, namely the λ-calculus with Milner's polymorphic type discipline; a language with imperative features (polymorphic references); and a skeletal module language with structures, signatures and functors. In each of the two first cases we show that the type inference system is consistent with an operational dynamic semantics. On the module level, polymorphic types correspond to signatures. There is a notion of principal signature. So-called signature checking is the module level equivalent of type checking. In particular, there exists an algorithm which either fails or produces a principal signature.
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Chattaway, John Antony. "Characterising the polymorphic BG gene family." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707953.
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Fraley, James B. "Improved Detection for Advanced Polymorphic Malware." NSUWorks, 2017. http://nsuworks.nova.edu/gscis_etd/1008.
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Malicious Software (malware) attacks across the internet are increasing at an alarming rate. Cyber-attacks have become increasingly more sophisticated and targeted. These targeted attacks are aimed at compromising networks, stealing personal financial information and removing sensitive data or disrupting operations. Current malware detection approaches work well for previously known signatures. However, malware developers utilize techniques to mutate and change software properties (signatures) to avoid and evade detection. Polymorphic malware is practically undetectable with signature-based defensive technologies. Today’s effective detection rate for polymorphic malware detection ranges from 68.75% to 81.25%. New techniques are needed to improve malware detection rates. Improved detection of polymorphic malware can only be accomplished by extracting features beyond the signature realm. Targeted detection for polymorphic malware must rely upon extracting key features and characteristics for advanced analysis. Traditionally, malware researchers have relied on limited dimensional features such as behavior (dynamic) or source/execution code analysis (static). This study’s focus was to extract and evaluate a limited set of multidimensional topological data in order to improve detection for polymorphic malware. This study used multidimensional analysis (file properties, static and dynamic analysis) with machine learning algorithms to improve malware detection. This research demonstrated improved polymorphic malware detection can be achieved with machine learning. This study conducted a number of experiments using a standard experimental testing protocol. This study utilized three advanced algorithms (Metabagging (MB), Instance Based k-Means (IBk) and Deep Learning Multi-Layer Perceptron) with a limited set of multidimensional data. Experimental results delivered detection results above 99.43%. In addition, the experiments delivered near zero false positives. The study’s approach was based on single case experimental design, a well-accepted protocol for progressive testing. The study constructed a prototype to automate feature extraction, assemble files for analysis, and analyze results through multiple clustering algorithms. The study performed an evaluation of large malware sample datasets to understand effectiveness across a wide range of malware. The study developed an integrated framework which automated feature extraction for multidimensional analysis. The feature extraction framework consisted of four modules: 1) a pre-process module that extracts and generates topological features based on static analysis of machine code and file characteristics, 2) a behavioral analysis module that extracts behavioral characteristics based on file execution (dynamic analysis), 3) an input file construction and submission module, and 4) a machine learning module that employs various advanced algorithms. As with most studies, careful attention was paid to false positive and false negative rates which reduce their overall detection accuracy and effectiveness. This study provided a novel approach to expand the malware body of knowledge and improve the detection for polymorphic malware targeting Microsoft operating systems.
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Chin, Ling Tsui. "Polymorphic light eruption-prevalence, physchosocial impact, treatment." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499920.
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Gray, Ian Christopher. "Polymorphic tandemly repeated sequences in human DNA." Thesis, University of Leicester, 1991. http://hdl.handle.net/2381/34415.
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Tandemly repeated tracts of DNA are a ubiquitous feature of eukaryote genomes. One class of tandem repeats, 'minisatellites', have been shown to be highly variable both in overall length and in the internal arrangement of variant versions of the repeating unit along the array. Consequently, both length and internal variation at these loci can be exploited to generate individual-specific profiles of use in forensic science and the establishment of family relationships. Recently it has been demonstrated that short dinucleotide repeats, or 'microsatellites', and other simple tandem repeat arrays can also show length variation. This work describes the isolation and characterization of simple tandem repeat arrays, and their application in a forensic science case. The evolutionary persistence of variability at tandem repeat loci is also explored. Simple tandem repeats isolated were frequently associated with other tandem repeats and interspersed repetitive elements, a phenomenon previously described for minisatellites and perhaps indicative that certain genomic regions show relaxed fidelity in the maintenance of large-scale DNA structure, allowing tandem array expansion and retroposon insertion. Although variability is low relative to minisatellites, microsatellites, owing to limited length, can readily be amplified from highly degraded DNA using the polymerase chain reaction. Consequently it was possible to identify positively the skeletal remains of a murder victim by comparing microsatellite profiles of the skeleton with those of the presumptive parents. Comparative studies of microsatellite and minisatellite loci between man and other primates indicate that in evolutionary terms, the variable state is reasonably persistent at microsatellite loci, whereas highly variable minisatellites show extreme evolutionary transience. Such transience was also demonstrated for two large 'midisatellite' loci, suggesting that highly variable tandem repeat loci are extremely unstable and transient, whereas lower variability leads to evolutionary persistence of the variable state.
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Turner, David N. "The polymorphic Pi-calculus : theory and implementation." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/395.
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We investigate whether the Pi-calculus is able to serve as a good foundation for the design and implementation of a strongly-typed concurrent programming language. The first half of the dissertation examines whether the Pi-calculus supports a simple type system which is flexible enough to provide a suitable foundation for the type system of a concurrent programming language. The second half of the dissertation considers how to implement the Pi-calculus efficiently, starting with an abstract machine for Pi-calculus and finally presenting a compilation of Pi-calculus to C. We start the dissertation by presenting a simple, structural type system for Pi-calculus, and then, after proving the soundness of our type system, show how to infer principal types for Pi-terms. This simple type system can be extended to include useful type-theoretic constructions such as recursive types and higher-order polymorphism. Higher-order polymorphism is important, since it gives us the ability to implement abstract datatypes in a type-safe manner, thereby providing a greater degree of modularity for Pi-calculus programs. The functional computational paradigm plays an important part in many programming languages. It is well-known that the Pi-calculus can encode functional computation. We go further and show that the type structure of lambda-terms is preserved by such encodings, in the sense that we can relate the type of a lambda-term to the type of its encoding in the Pi-calculus. This means that a Pi-calculus programming language can genuinely support typed functional programming as a special case. An efficient implementation of Pi-calculus is necessary if we wish to consider Pi-calculus as an operational foundation for concurrent programming. We first give a simple abstract machine for Pi-calculus and prove it correct. We then show how this abstract machine inspires a simple, but efficient, compilation of Pi-calculus to C (which now forms the basis of the Pict programming language implementation).
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Fenton, Brian Forbes Neil. "Studies on polymorphic proteins of Plasmodium falciparum." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/14835.
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Parambil, Jose Varghese. "Template induced polymorphic selectivity in pharmaceutical crystallisation." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/27651.
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Polymorphism in pharmaceutical drug crystals causes differences in their bioavailability, stability and processability. Hence, identifying different crystal polymorphs of an active ingredient during the early stages of drug development and controlling crystal polymorphism during the manufacturing process are important aspects of pharmaceutical crystallisation. Nucleation and growth of different polymorphs in a crystallising solution are regulated by a delicate balance between thermodynamic and kinetic factors. Crystal nucleation predominantly occurs via heterogeneous nucleation pathway as it is energetically favourable than homogeneous nucleation. Template-induced nucleation approach aims to utilise the advantage of heterogeneous nucleation to induce nucleation of specific crystal polymorphs through interfacial interactions between a preformed solid surface and solute molecules at the nucleation stage. In template-induced crystallisation, templates with specific surface properties that can act as heterogeneous nucleation sites are introduced in contact with the crystallising solution. Specific interactions between the template surface and solute molecules are known to influence nucleation and growth of crystal polymorphs. However, the effects of template surface chemistry and other operating conditions such as temperature and supersaturation on template-induced crystallisation is not clearly understood. Hence, the aim of this study is to probe the combined effects of surface chemistry, crystallisation temperature, supersaturation, and solvent on template-induced crystallisation experimentally and consequent development of a molecular modelling approach to study template-induced nucleation. This could help in establishing template-induced nucleation as a method to achieve preferential nucleation of crystal polymorphs and to support template chemistry as a novel parameter for polymorph screenings. Carbamazepine (CBZ) was selected as the model drug compound and silanised glass vials were chosen as the template surfaces. CBZ crystallisation from ethanol solutions on templates with cyano functional surface groups led to selective nucleation of metastable form II crystals while the control surfaces resulted in concomitant nucleation of both form II and stable form III crystals. On mercapto and fluoro templates, CBZ crystallised preferentially as form III polymorph. These variations in the polymorphic outcome with template chemistry, temperature and supersaturation were mapped on to template-induced polymorphic domain (TiPoD) plots. The analysis of TiPoD plots showed that the template-induced nucleation mechanism was prominent within a narrow range of supersaturation across the temperature range studied. The influence of solvents on template-induced nucleation of CBZ polymorphs was also investigated by constructing TiPoD plots in five different solvents. These studies revealed that the templates were less effective in altering polymorphic outcome in highly polar solvent in comparison with the less polar solvents. Interfacial interactions between the template surface and CBZ crystal polymorphs were calculated through molecular modelling. The simulation results suggest that those templates exhibiting favourable interaction energies with the dominant crystal facets of a specific polymorph preferentially induce nucleation of that crystal form.
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Lee, Rachael. "Extreme conditions crystallography of polymorphic co-crystals." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12065/.
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This work has two principal sections. The first section is a study of the hydrogen bonding in a series of urea inclusion compounds, utilising neutron diffraction methods and a novel technique for growing neutron diffraction-suitable single crystals. The second section focusses on high pressure crystallography as a technique for exploring polymorphic landscapes, of a series of acid-base co-crystals, and the well-known active pharmaceutical ingredient 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY). Single crystal neutron structures at several temperatures have been determined for -phase urea inclusion compounds containing hexadecane, 1,6-dibromohexane and 2,7-octanedione guests. The neutron structure of the ‘partial channel’ co-crystal of urea and DMF is also reported. This includes an in-depth discussion and analysis of the structure and bonding of this urea series, in particular, how the guest compound affects the symmetry and hydrogen bonding of the host urea network. Additionally, the challenge of obtaining crystals suitable for neutron diffraction is addressed and a new heating/cooling device to aid crystallisation is presented. Pyridine and formic acid have been crystallised at differing ratios by both cryo-crystallisation and compression in a diamond anvil cell. Mixtures of the liquids in 1:1, 1:2 and 1:4 ratios all crystallise at high pressure, while only the 1:1 and 1:4 compositions were crystallised by in situ low temperature capillary crystallisation. The 1:2 structure crystallised by high pressure is a previously unknown co-crystal of pyridine - formic acid. For the 1:4 mixture, a new polymorph has been identified at a pressure of 14.2 kbar with a distinctly different structure and bonding pattern to that of the previously reported low temperature form. Five new co-crystals of 2,6-dimethylpyridine (DMP) with formic acid (FA) were crystallised by application of pressure in a diamond anvil cell and by in situ cryo-crystallisation. Mixtures in ratios 1:1, 1:2 and 1:3 of DMP: FA have been crystallised via both methods. Both the 1:2 and 1:3 co-crystals exhibit high pressure/low temperature polymorphism. ROY has been crystallised from acetone solution using a diamond anvil cell. The needle-like form obtained, named ONP shows similarities with the ORP, ON and Y forms, determined by Raman spectroscopy. The ONP crystals were recovered from the pressure cell by freezing with liquid nitrogen. Synchrotron X-ray data were collected on the sample, although no structure solution and refinement was possible. The unit cell of the ONP shows a crystallographic relationship to the ORP form.
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Petrucciani, Tommaso. "Polymorphic set-theoretic types for functional languages." Thesis, Sorbonne Paris Cité, 2019. http://www.theses.fr/2019USPCC067.
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Cette thèse porte sur l'étude des types ensemblistes : des types qui contiennent des connecteurs d'union, d'intersection et de négation. Les types ensemblistes permettent de typer de manière très précise plusieurs constructions des langages de programmation (comme par exemple les branches conditionnelles, le filtrage par motif et la surcharge des fonctions) lorsqu'ils sont utilisés avec une notion appropriée de sous-typage. Pour définir celle-ci, nous utilisons l'approche du sous-typage sémantique, dans laquelle les types sont interprétés comme des ensembles, et où le sous-typage est défini comme l'inclusion ensembliste. Dans la plupart de cette thèse, les types ensemblistes sont polymorphes, dans le sens où ils contiennent des variables de type pour permettre le polymorphisme paramétrique.La thèse étend les travaux précédents sur les types ensemblistes et le sous-typage sémantique en montrant comment les adapter à de nouveaux contextes et comment les utiliser pour typer plusieurs aspects des langages fonctionnels. Elle se compose de trois parties.La première partie porte sur une étude des langages typés de manière implicite avec polymorphisme du "let" et inférence de types (contrairement aux travaux précédents sur le sous-typage sémantique qui étudiaient des langages typés explicitement). Nous y décrivons un lambda-calcul typé implicitement avec un système de types dont nous démontrons la correction. De même, nous y étudions l'inférence de types dont nous démontrons la correction et la complétude. Enfin, nous montrons comment rendre l'inférence plus précise quand les programmes sont partiellement annotés avec des types.La deuxième partie décrit une nouvelle approche permettant d'étendre un système de types statique avec du typage graduel; l'originalité venant du fait que nous décrivons le système de types de façon déclarative, lorsque les systèmes existants proposent des descriptions algorithmiques. Nous illustrons cette approche en ajoutant le typage graduel à un système de types à la Hindley-Milner sans sous-typage. Nous décrivons pour cela un système de types déclaratif, un processus de compilation vers un langage avec vérifications de type dynamiques (ou "casts"), et nous présentons un système d'inférence de types correct et complet. Ensuite, nous y ajoutons les types ensemblistes, en définissant une relation de sous-typage sur les types graduel ensemblistes, puis en présentant un système d'inférence de types correct pour le système étendu.La troisième partie porte sur l'étude des sémantiques non-strictes. Les systèmes existants qui utilisent le sous-typage sémantique ont été développés pour des langages avec appel par valeur et ne sont pas sûrs pour des sémantiques non-strictes. Nous montrons ici comment les adapter pour garantir leur sûreté en appel par nécessité. Pour faire ça, nous introduisons dans les types une représentation explicite de la divergence, afin que le système des types puisse distinguer les expressions qui ne demandent pas d'évaluation de celles qui la demandent et pourraient ainsi divergerWe study set-theoretic types: types that include union, intersection, and negation connectives. Set-theoretic types, coupled with a suitable subtyping relation, are useful to type several programming language constructs – including conditional branching, pattern matching, and function overloading – very precisely. We define subtyping following the semantic subtyping approach, which interprets types as sets and defines subtyping as set inclusion. Our set-theoretic types are polymorphic, that is, they contain type variables to allow parametric polymorphism.We extend previous work on set-theoretic types and semantic subtyping by showing how to adapt them to new settings and apply them to type various features of functional languages. More precisely, we integrate semantic subtyping with three important language features.In Part I we study implicitly typed languages with let-polymorphism and type inference (previous work on semantic subtyping focused on explicitly typed languages). We describe an implicitly typed lambda-calculus and a declarative type system for which we prove soundness. We study type inference and prove results of soundness and completeness. Then, we show how to make type inference more precise when programs are partially annotated with types.In Part II we study gradual typing. We describe a new approach to add gradual typing to a static type system; the novelty is that we give a declarative presentation of the type system, while previous work considered algorithmic presentations. We first illustrate the approach on a Hindley-Milner type system without subtyping. We describe declarative typing, compilation to a cast language, and sound and complete type inference. Then, we add set-theoretic types, defining a subtyping relation on set-theoretic gradual types, and we describe sound type inference for the extended system.In Part III we consider non-strict semantics. The existing semantic subtyping systems are designed for call-by-value languages and are unsound for non-strict semantics. We adapt them to obtain soundness for call-by-need. To do so, we introduce an explicit representation for divergence in the types, allowing the type system to distinguish the expressions that are already evaluated from those that are computations which might diverge
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Flannery, Kevin E. "Conjunctive polymorphic type checking with explicit types." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54527.
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An expressive type language and the ability to do compile-time type inference are desirable goals in language design, but the attainment of the former may preclude the possibility of the latter. Specifically, the type conjunction operator (type intersection) induces a rich type language at the expense of decidability of the typeable expressions. Two extreme alternatives to this dilemma are to abandon type inference (and force the programmer to, essentially, supply a derivation for his type claims) or to abandon (or restrict) type conjunction. This work presents a third alternative in which the programmer, at times, may be required to supply explicit types in order for type inference to succeed. In this way, the power of conjunctive types is preserved, yet compile-time type inference can be done for a large class of polymorphic functions, including those typeable with parametric types.
To this end, we introduce a simple combinator based language with typing rules based on type conjunction and a subtype relation, of sorts, called "weaker." The validity of the type rules with respect to the usual interpretation of "type" is shown, along with the undecidability of the type relation. It is shown how the computational portion of the language can be modified to accommodate explicit type information which may direct an automatic type derivation. This new language has the principal type property with respect to a decidable relation, although deciding this relation is shown to be an NP-Complete problem. The language is extended to accommodate type fixed points, and extended further to allow all expressions with parametric types to be typed automatically, and to accommodate integers, pairs, sums, and abstract types in the form of type generators.Ph. D.
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Schmid, Balthasar. "Polymorphic O-demethylation of dextrometorphan in man /." Bern, 1985. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Jones, Carys Wynn. "Habitat and rest site selection in polymorphic Lepidoptera." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358332.
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Clark, Rebecca. "The evolutionary genetics of polymorphic butterfly wing patterns." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428582.
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Zhang, Qingfei. "Crystallographic studies of the insulin-linked polymorphic region." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/50345.
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Gunther, William J. "Some Results on Classical Semantics and Polymorphic Types." Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/645.
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In the first chapter we consider the simply typed-calculus over one ground type with a discriminator which distinguishes terms, augmented additionally with an existential quantifier and a description operator, all of lowest type.
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Thompson, Gregory B. "Predicting Polymorphic Phase Stability in Multilayered Thin Films." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1046469309.
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Pond, Emma. "Characterisation of tight junctions in polymorphic light eruption." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/characterisation-of-tight-junctions-in-polymorphic-light-eruption(8d043c3d-7f97-41e1-9b87-9523c5b639d6).html.
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Polymorphic light eruption (PLE) is the most common photodermatosis, affecting ~17% of the population. PLE is a delayed-type hypersensitivity response to an antigen induced by solar ultra-violet radiation (UVR). Its effects vary between patients, but the main symptom is a non-scarring, red papular rash in areas exposed to UVR. An effective therapy is low dose ultra-violet B (NBUVB) phototherapy. It is thought that NBUVB phototherapy desensitises the skin to further UVR exposure, but the mechanism by which this happens is unknown. Current immune based studies have been unable to clarify a mechanism as to how PLE arises. However, research in other skin diseases, such as psoriasis and atopic dermatitis, has shown that the barrier function of the skin is compromised by these disorders. Furthermore, research in lesional PLE skin showed an increase in barrier permeability of the skin. Recent research has specifically linked claudin proteins of tight junctions to the barrier dysfunction. Therefore, this study used quantitative immunofluorescent staining to measure tight junction (TJ) proteins and other barrier proteins of interest. Barrier function was also measured by transepidermal water loss (TEWL); a tracer dye penetration assay was used to measure TJ barrier function specifically. All measurements were made in non-lesional PLE skin, as compared to skin from healthy human volunteers. In photoprotected PLE skin the TJ protein claudin-1 was significantly reduced compared to healthy skin. The use of a tracer dye highlighted there was a reduction in TJ barrier function in PLE skin compared to healthy individuals. PLE and healthy skin were then exposed to ultra-violet B (UVB) and 24h later TJ proteins and TJ barrier function were measured. There was no change to claudin-1 after UVB exposure in PLE skin, but claudin-7 was reduced and claudin-12 increased. In contrast, in UVB-irradiated skin in normal controls after UVB exposure claudin-7 and claudin-12 were both increased, whilst claudin-1 was reduced. In PLE patients there was no further change to TJ barrier function, however, in normal controls, skin TJ barrier function was reduced post UVB. Both in healthy and PLE skin TEWL was unchanged before and after UVB exposure. Lastly TJ proteins were investigated after NBUVB in PLE patients. There was a further reduction in claudin-1 in PLE patients as well as a reduction in the TJ protein occludin, however the stratum corneum was significantly thickened. It could be suggested that this is a compensatory measure for the reduction seen in TJ barrier proteins, however further studies are needed to understand this. These data show significant differences in the TJ skin barrier in patients with PLE as compared to healthy human volunteers before and after UVB exposure. Furthermore, in PLE skin there is a significant change to the epidermis after NBUVB phototherapy. These data demonstrate that TJ protein expression and function is altered in PLE skin and may contribute to aetiology of the disorder, however the role of TJ barrier in aetiology is yet to be firmly established.
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Oliva, Pavia Meritxell. "Functional impact of polymorphic inversions in the human genome." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/286269.
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Una inversió és una reordenació genòmica que altera l'orientació d'una seqüència genòmica específica. Les inversions són reordenaments balancejats i no impliquen necessàriament un guany o pèrdua d'ADN, però tot i així poden alterar el contingut genètic original i causar-hi mutacions. A més, les inversions poden modificar els patrons de recombinació d’ADN tan de la seqüència genòmica continguda en la inversió com també en regions flanquejants. Conseqüentment, les inversions poden estar associades a certs fenotips o malalties, influir en l’evolució dels individus portadors a través de processos adaptatius o jugar un paper clau en l’origen de noves espècies. Per tot això, expandir el nostre coneixement de les inversions és clau per a la comprensió en profunditat de la variació del genoma i les seves conseqüències. Tanmateix, la nostra comprensió tan de l’abundància com de l’impacte funcional de les inversions en el genoma humà és escàs, i se sap ben poc sobre la seva associació a canvis d'expressió gènica en aquesta espècie.
Durant els últims 10 anys, l’aparició de noves tecnologies de seqüenciació genòmica ha fet permès l'estudi de les variacions estructurals a gran escala, incloent les inversions. Aprofitant aquesta oportunitat,, el projecte INVFEST ha dedicat esforços en la construcció del catàleg d' inversions polimòrfiques en humans més precís i exhaustiu fins a la data. Per aconseguir-ho,, hem demostrat que GRIAL, l’únic mètode disponible dissenyat específicament per identificar inversions a partir de l’alineament de fragments aparellats (“PEM”), prediu inversions amb més precisió i eficiència que altres mètodes de detecció basats en “PEM”, i sobretot refina molt millor els punts de trencament. A més, les prediccions d’inversió de GRIAL s’han filtrat utilitzant diversos filtres pre i post mapeig, juntament amb la inspecció manual de casos complexos, aconseguint així una reducció de la taxa de falsos positius.
A continuació, per obtenir una major comprensió sobre l'impacte funcional de les inversions polimòrfiques en el genoma humà, hem examinat el solapament de 44 inversions amb gens. En general, els nostres resultats mostren que les inversions tendeixen a estar ubicades en regions intergèniques encara que hem identificat un 13,6% dels casos on les inversions afecten exons de gens. Per tal d’analitzar com les inversions afecten l’expressió gènica, s’han realitzat dos estratègies complementaries. La primera consisteix en un anàlisi d’expressió diferencial en línies cel·lulars limfoblàstiques (“LCLs”) de 527 mostres de poblacions HapMap europees, asiàtiques i africanes. La segona està basada en l’anàlisi de marcadors d’inversió (“tag-SNPs”) associats a canvis en l’expressió de gens en diferent teixits. Conjuntament, hem identificat 19 inversions que modulen l'expressió gènica de 43 gens en múltiples teixits. Aquests resultats semblen coherents, ja que un subconjunt (N = 11) de les associacions trobades en “LCLs” ha estat identificat per ambdós mètodes. En concret, hem identificat una inversió que afecta l'expressió de gens paràlegs codificants de les proteïnes IFITM2 i IFITM3 en limfoblasts. Hem validat també la metodologia emprada per a l'anàlisi d'expressió diferencial reproduint associacions conegudes amb gens de dues inversions àmpliament estudiades (17q21.31, 8p23.1), identificant així noves associacions no descrites entre 17q21.31, 8p23.1 i l'expressió de 6 gens en total. A més, en el cas de 17q21.31, observem que almenys 2 d'aquests gens estan associats a reordenaments estructurals en la regió estudiada. Finalment, hem buscat possibles associacions d’inversions amb malalties, i hem identificat un cas on la inversió sembla estar associada amb esclerosi lateral amiotròfica en dos estudis d’associació genòmica (“GWAS”) diferents.
El coneixement adquirit en aquest estudi contribueix així a una millor comprensió del paper de les inversions polimòrfiques en la regulació de l'expressió gènica i en les conseqüències d'aquest tipus de variant estructural tan poc estudiada en humans.An inversion is a balanced genomic rearrangement that alters the orientation of a specific genomic sequence. Despite not usually causing gain or loss of DNA, inversions can alter the original genetic background and produce mutational and positional effects on genes. In addition, inversions can alter recombination patterns both on the DNA sequences encompassed by them and in their vicinity. Therefore, inversions may associate with certain phenotypes or diseases, shape the evolutionary fate of the carriers by adaptive processes or even play a role in the origin of new species. For all that, increasing our knowledge of inversions constitutes a key issue for in-depth understanding of genome variation and its consequences. However, little is known about the prevalence and functional impact of inversions in the human genome, and in particular of their association with gene expression changes in humans. For the last 10 years, the advent of novel genomic technologies has enabled the study of SVs, including inversions, in a high-throughput fashion within and across species. State of the art genomic research provides the means and tools to explore the human genome in detail and expand our knowledge of inversions. Against this backdrop, the INVFEST project has devoted efforts to build the most accurate and exhaustive catalogue of human polymorphic inversions to date. For that, we have benchmarked GRIAL, currently the only paired-end mapping (PEM) based algorithm specifically designed to predict inversions, and demonstrated that performs with more accuracy and efficiency compared to other PEM based SV-detection methods, particularly in refining inversion BPs. In addition, we have curated GRIAL inversion predictions by using several pre and post PEM mapping filters coupled with manual inspection of complex cases and minimized the rate of false positive predictions. Next, to gain further insight on the functional impact of polymorphic inversions in the human genome, we examined the overlap of 44 different inversions with genes. Overall, our results show that inversions tend to be located in intergenic regions but in 13.6% of the cases gene exons are affected. We performed two complementary approaches to identify inversion associations with gene expression. First, we performed a linear regression analysis in three different expression datasets derived from 527 lymphoblastoid cell lines (LCLs) of European, Asian and African HapMap individuals. Second, we interrogated blood and non-blood tissues by contrasting expression quantitative trait loci (eQTL) data with inversion tag-SNPs. We report 19 inversion rearrangements that modulate gene expression of 43 genes in several tissues. These results seem consistent as a subset (N = 11) of the associations found in LCLs has been identified by both approaches. Interestingly, we have identified an inversion that affects the expression of paralogous protein-coding genes (IFITM2/IFITM3) in lymphocyte-derived cells. We have also validated the methodology used for differential expression analysis by reproducing known effects of two well-studied inversions (17q21.31, 8p23.1) and identified novel associations of both inversion haplotypes with the expression of 6 genes. Moreover, we observe that at least 2 of these genes are associated to 17q21.31 structural rearrangements. Finally, we have looked for possible associations of inversions with disease and found one inversion that seems to be associated with amyotrophic lateral sclerosis in two different GWAS studies. Insight gained in this study could therefore contribute to a better understanding of the role of polymorphic inversions in the regulation of gene expression and the consequences of this understudied type of genetic variants in humans.
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Williams, Ceili. "Structure/property relationships in a polymorphic nonlinear optical crystal." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314895.
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Morgan-Warren, Robert James. "Structural and biophysical differences between polymorphic ovine PrP proteins." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614732.
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Hannay, Jo E. "Abstraction barriers and refinement in the polymorphic lambda calculus." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/801.
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This thesis examines specification refinement in the setting of polymorphic type theory and a complementary logic for relational parametricity. The starting point is the specification of abstract data types as done in the discipline of algebraic specification. Here, algebras are seen to match the standard notion of data type, i.e., a data representation together with operations on that data representation. An abstract data type is then a collection of data types sharing some well-defined abstract properties. In algebraic specification, these properties are specified algebraically by axioms in some suitable logic. Specification refinement then encompasses the idea that high-level specifications may be stepwise refined to executable programs that satisfy the initial specification; all in the framework of formal language and logic. This makes certain aspects of program development amenable to formal, computer-aided proofs of correctness. On the other hand, the discipline of type theory, lambda calculus, and its semantics is the prime field for research on programming languages. This framework is capable of characterising essentially any existing sequential programming-language feature, also advanced features such as recursive types, polymorphism and class-based object orientation. Furthermore, type theory provides a powerful framework for mechanised reasoning. This thesis is a contribution to lifting the idea of algebraic specification refinement into the more powerful domain of type theory and lambda calculus, thus giving the opportunity to expand in a sensible way a traditionally first order and functional framework to a wider range of programming aspects. We take a particular account of specification refinement and express it in a type-theoretic setting consisting of the polymorphic lambda calculus and a logic for relational parametricity. Key elements of algebraic specification are internalised in the syntax, e.g., data types viz. algebras are inhabitants of existential type, the latter providing essential data abstraction. For data types with only first-order operations, this setting automatically resolves certain issues of specification refinement, such as observational equivalence, stability and input sorts. After establishing a correspondence at first order, thus implanting the idea of algebraic specification refinement into the type-theoretic setting, the scene is set for lifting the idea of algebraic specification refinement to any number of programming features. In this thesis we focus on the generalisations to higher-order functions and to polymorphism. A simulation relation between two data types is a relation between their data representations that is preserved by their respective sets of operations. Using simulation relations is a classical way of explaining data refinement and observational equivalence. This combines with specification refinement to form specification refinement up to observational equivalence. With higher-order operations, however, we encounter in the logic a phenomenon related to what happens on the semantic level, i.e., the standard notion of refinement relation in the form of logical relations does not compose and the correspondence with observational equivalence is lost. In the logic it turns out that the standard notion of simulation relation fails to take into account a certain aspect of the abstraction barrier provided by existential types. We remedy this by proposing an alternative notion of simulation relation that observes this abstraction barrier more closely. We do this in two related ways; one relates to syntactic models while the other relates to a non-syntactic PER-model more apt for interpretive investigations. In algebraic specification, there is a universal proof method for specification refinement up to observational equivalence. This method can be imported soundly into the type-theoretic setting by asserting certain axioms. At first order, showing soundness for these axioms is straight-forward w.r.t. the standard parametric PER model for the logic. At higher order there are two problems. First, these axioms seemingly do not hold in the standard model. Secondly, the axioms speak in terms of simulation relations. At higher order, it is pertinent to have versions of the axioms featuring the abstraction barrier-observing simulation relations above, and to prove soundness for these poses an additional challenge. We show that the pure higher-order aspect of this problem can be solved by giving a setoid-based semantics. For the remaining task, we continue working from the observation that standard definitions do not observe abstraction barriers closely enough. Hence, we propose an alternative interpretation into the PER-model for data types that captures the abstraction barrier provided by existential types. The main contribution of this thesis is thus in generalising a prominent account of specification refinement to higher order and polymorphism via type theory incorporating relational parametricity. We also shed light on short-comings in the logic, as well as in the standard semantics, regarding the abstraction barrier provided by existential types. Two central contributions, namely abstraction barrier-observing simulation relations and abstraction barrier-observing semantics for data types, are the result of observing these short-comings. Finally, the work in this thesis also lays a foundation on which to adapt specification refinement to an object-oriented setting, because the theoretical concepts underlying object orientation can be seen as extensions of those for abstract data types.
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Larsen, Graeme D. "A polymorphic framework for understanding the diffusion of innovations." Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424037.
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De, Aguiar J. C. S. "Studies on the polymorphic schizont antigen of Plasmodium chabaudi." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383640.
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Millard, Thomas Paul. "Genetics of cutaneous lupus erythematosus and polymorphic light eruption." Thesis, King's College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271287.
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Goulart, V. D. L. R. "Investigations of polymorphic colour vision in new world primates." Thesis, University of Salford, 2017. http://usir.salford.ac.uk/43613/.
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Primate colour vision in New World primates is intriguingly complex; show a polymorphism where males are obligatory dichromats (i.e. perception similar to colour-blind humans that cannot differentiate red from green) Females can be either dichromats or trichromats (vision similar to normal humans). The role of such polymorphism remains unclear; however, two often tested hypotheses are related to predator detection and the locating of specific food resources. Here we investigated behavioural changes in male and female primates relating to the colour vision phenotypes and niche divergence as an adaptive feature responsible for maintaining colour vision polymorphism. For polymorphic colour vision to be complementary advantageous, primates should be able to perceive the behavioural changes resulting from sensory abilities of conspecifics. Cooperation tests were used with captive primates to investigate the possibility of primates recognising the visual ability of other individuals in the group. A molecular study of medium-long wavelength sensitive opsin alleles in Pitheciidae indicated a greater variation than reported in the literature and such complexity might increase the number of females with trichromatic colour vision. From a geographical analysis of South American primates, we found that primates avoided areas with high predator richness; however, species that possessed more complex colour vision systems were unaffected by predator richness. Thus, colour vision might be related to complementary advantages in having different colour vision systems in the same group (again increasing the probability of trichromats). Alternative methodologies (i.e. Machine Learning and Computer Vision) were employed to investigate the fitness of different phenotypes in detecting camouflaged targets showing that, contrary to from traditional hypothesis of advantages of dichromatic colour vision, trichromatic colour vision models are best suited for breaking through camouflage. A proof of concept to improve the collection of behavioural data and to investigate the role of cooperation for the maintenance of polymorphic colour vision is also presented. In conclusion, colour vision polymorphism in New World primates enhances the visual abilities of primate groups and is maintained by niche sexual diversification.
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Fierling, Julien. "Polymorphic bio-filaments and their interaction with biological membranes." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE015/document.
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Cette thèse développe, dans le cadre de la biophysique, des modèles théoriques centrés sur les interactions entre les bio-filaments, de longs polymères présents dans les cellules biologiques et les membranes biologiques, qui protègent les cellules de leur environnement. La thèse est divisée en trois parties, traitant différents systèmes. Dans un premier temps, un modèle admettant plusieurs états de courbure préférée des bio-filaments est développé. Ce type de filaments est forcé à former un anneau et leur interaction avec des membranes tubulaires qu'ils enlacent est discutée. Deuxièmement, les déformations de membranes biologiques modèles sous l'action de filaments appliquant des couples sont calculées, dans le régime linéaire. Finalement, la motilité de la bactérie Spiroplasma est abordée. Les résultats préliminaires d'un modèle élastique sont donnésThis work focuses on the development of theoretical models in the framework of biophysics. In particular, it deals with the interactions between bio-filaments (long polymer chains found in biological cells) and biological membranes which protect cells from their environment. It is divided in three main parts, where different systems are studied. Firstly, a model going beyond the Worm-Like Chain model is developed to take into account different preferred states of curvature of the constituents of the bio-polymer chains. This kind of filaments are forced to close into a ring and their interactions with tubular membranes they entwine are discussed. Secondly, the deformations induced to biological membranes by torque-applying bio-filaments are discussed in the linear regime. Finally, the motility of the bacteria Spiroplasma. Preliminary results on an elastic model describing the cell motility are given
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Woodburn, Mary Alice. "Random amplified polymorphic DNA (RAPD) analysis of Bacillus sphaericus." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07102009-040429/.
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Price, Jared Calvin. "The Bioluminescence Heterozygous Genome Assembler." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4346.
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High-throughput DNA sequencing technologies are currently revolutionizing the fields of biology and medicine by elucidating the structure and function of the components of life. Modern DNA sequencing machines typically produce relatively short reads of DNA which are then assembled by software in an attempt to produce a representation of the entire genome. Due to the complex structure of all but the smallest genomes, especially the abundant presence of exact or almost exact repeats, all genome assemblers introduce errors into the final sequence and output a relatively large set of contigs instead of full-length chromosomes (a contig is a DNA sequence built from the overlaps between many reads). These problems are dramatically worse when homologous copies of the same chromosome differ substantially. Currently such genomes are usually avoided as assembly targets and, when they are not avoided, they generally produce assemblies of relatively low quality. An improved algorithm for the assembly of such data would dramatically improve our understanding of the genetics of a large class of organisms. We present a unique algorithm for the assembly of diploid genomes which have a high degree of variation between homologous chromosomes. The approach uses coverage, graph patterns and machine-learning classification to identify haplotype-specific sequences in the input reads. It then uses these haplotype-specific markers to guide an improved assembly. We validate the approach with a large experiment that isolates and elucidates the effect of single nucleotide polymorphisms (SNPs) on genome assembly more clearly than any previous study. The experiment conclusively demonstrates that the Bioluminescence heterozygous genome assembler produces dramatically longer contigs with fewer haplotype-switch errors than competing algorithms under conditions of high heterozygosity.
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Özgen, Mustafa. "A type inference algorithm and transition semantics for polymorphic C /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA318845.
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Thesis (M.S. in Computer Science) Naval Postgraduate School, September 1996.Thesis advisor(s): Dennis Volpano. "September 1996." Includes bibliographical references (p. 111-112). Also available online.
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Papadopoulos, Sarantos. "Untersuchungen genomischer Veränderungen von Mammakarzinomzellen mittels Random amplified polymorphic DNA." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962689114.
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Johansson, Börje. "An implementation of Milner's CCS with a polymorphic type system." Licentiate thesis, Luleå tekniska universitet, EISLAB, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18530.
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Brunet, Sylvain. "Mechanism of drug-induced torsade de pointes polymorphic ventricular tachycardia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0006/NQ44373.pdf.
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Jalai, Gholam Reza. "Study of polymorphic human trophoblast antigen bound to maternal antibody." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300780.
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Özgen, Mustafa. "A type inference algorithm and transition semantics for polymorphic C." Thesis, Monterey, California. Naval Postgraduate School, 1996. http://hdl.handle.net/10945/9097.
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Approved for public release; distribution is unlimited.In an attempt to bring the ML-style type inference to the C programming language, Smith and Volpano developed a type system for a dialect of C, called PolyC SmV96a SmV95b. PolyC extends C with ML-style polymorphism and a limited form of higher-order function. Smith and Volpano proved a type soundness theorem that basically says that evaluation of a well-typed PolyC program cannot fail due to a type mismatch. The type soundness proof is based on an operational characterization of a special kind of semantic formulation called a natural semantics. This thesis presents an alternative semantic formulation, called a transition semantics, that could be used in place of the natural semantics to prove type soundness. The primary advantage of the transition semantics is that it eliminates the extra operational level, but the disadvantage is that it consists of many more evaluation rules than the natural semantics. Thus it is unclear whether it is a suitable alternative to the two-level approach of Smith and Volpano. Further, the thesis gives the first full type inference algorithm for the type system of PolyC. Despite implicit variable dereferencing found in PolyC, the algorithm turns out to be a rather straight-forward extension of Damas and Milner's algorithm W DaM82. The algorithm has been implemented as an attribute grammar in Grammatech's SSL and a complete source code listing is given in the Appendix
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張艷馨 and Yim-hing Cheung. "Rare types and polymorphic variants of HPV in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31970448.
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Fuentes, Hernandez Ayari. "Metabolic cooperation and the polymorphic secretion of invertase in yeast." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557822.
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Barker, Nathaniel M. "The Influence of Structure in Platinum(II) Polypyridyl Polymorphic Complexes." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1627665370500068.
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