To see the other types of publications on this topic, follow the link: Rational.
Dissertations / Theses on the topic 'Rational'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Rational.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
車谷, 優樹. "Congurations of Rational Curves on Rational Elliptic Surfaces." 京都大学, 2014. http://hdl.handle.net/2433/214449.
Full text
2
Campbell, Peter G. "Rational agency." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28592.
Full textAbstract:
It is claimed that action discourse provides us with a criterion of adequacy for a theory of action; that with action discourse we have a family of concepts which a theory of action must accommodate. After an exegesis of Davidson's essay "Agency", it is argued that his semantics of action is incompatible with our concepts of motivation and responsibility for action and of attributions of action and agency, and must, therefore, be rejected. A theory of rational agency is presented within which are to be found accounts of intention, coming to intend, intentional action, and an alternative semantics of action which connects the action essentially to agency. The theory of rational agency is then used to illuminate the concepts of trying, compulsion, autonomy and involuntariness, mistake, accident, and the so-called active-passive distinction.Arts, Faculty of
Philosophy, Department of
Graduate
3
McBurney, Peter John. "Rational interaction." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250477.
Full text
4
Cao, Xinyu. "Rational spamming." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107528.
Full textAbstract:
Thesis: S.M. in Management Research, Massachusetts Institute of Technology, Sloan School of Management, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 57-58).
Advertising on social media faces a new challenge as consumers can actively choose which advertisers to follow. Tracking company accounts, owned by 93 TV shows on the most popular tweeting website in China, provides evidence that firms advertise intensively, although doing so appears to drive followers away. An analytical model suggests that consumers with limited attention may rationally choose to unfollow a firm. This happens if consumers already know enough about the firm's quality and if the firm advertises too intensely. However, firms might still find intensive advertising the optimal strategy - if a firm is perceived as having a lesser quality offering, it wants to advertise aggressively to change consumers' beliefs about its quality; if a firm is perceived as having a higher quality offering, it also wants to advertise intensively, but in an effort to crowd-out advertising messages from its competitors.
by Xinyu Cao.
S.M. in Management Research
5
Khodorovskiy, Tatyana. "Symplectic Rational Blow-Up and Embeddings of Rational Homology Balls." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10189.
Full textAbstract:
We define the symplectic rational blow-up operation, for a family of rational homology balls \(B_n\), which appeared in Fintushel and Stern's rational blow-down construction. We do this by exhibiting a symplectic structure on a rational homology ball \(B_n\) as a standard symplectic neighborhood of a certain 2-dimensional Lagrangian cell complex. We also study the obstructions to symplectically rationally blowing up a symplectic 4-manifold, i.e. the obstructions to symplectically embedding the rational homology balls \(B_n\) into a symplectic 4-manifold. First, we present a couple of results which illustrate the relative ease with which these rational homology balls can be smoothly embedded into a smooth 4-manifold. Second, we prove a theorem and give additional examples which suggest that in order to symplectically embed the rational homology balls \(B_n\), for high \(n\), a symplectic 4-manifold must at least have a high enough \(c^2_1\) as well.Mathematics
6
Lazda, Christopher David. "Rational homotopy theory in arithmetic geometry : applications to rational points." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24707.
Full textAbstract:
In this thesis I study various incarnations of rational homotopy theory in the world of arithmetic geometry. In particular, I study unipotent crystalline fundamental groups in the relative setting, proving that for a smooth and proper family of geometrically connected varieties f:X->S in positive characteristic, the rigid fundamental groups of the fibres X_s glue together to give an affine group scheme in the category of overconvergent F-isocrystals on S. I then use this to define a global period map similar to the one used by Minhyong Kim to study rational points on curves over number fields. I also study rigid rational homotopy types, and show how to construct these for arbitrary varieties over a perfect field of positive characteristic. I prove that these agree with previous constructions in the (log-)smooth and proper case, and show that one can recover the usual rigid fundamental groups from these rational homotopy types. When the base field is finite, I show that the natural Frobenius structure on the rigid rational homotopy type is mixed, building on previous results in the log-smooth and proper case using a descent argument. Finally I turn to l-adic étale rational homotopy types, and show how to lift the Galois action on the geometric l-adic rational homotopy type from the homotopy category Ho(Q_l-dga) to get a Galois action on the dga representing the rational homotopy type. Together with a suitable lifted p-adic Hodge theory comparison theorem, this allows me to define a crystalline obstruction for the existence of integral points. I also study the continuity of the Galois action via a suitably constructed category of cosimplicial Q_l-algebras on a scheme.
7
Paradis, Philippe. "On the Rational Retraction Index." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23111.
Full textAbstract:
If X is a simply connected CW complex, then it has a unique (up to isomorphism) minimal Sullivan model. There is an important rational homotopy invariant, called the rational Lusternik–Schnirelmann of X, denoted cat0(X), which has an algebraic formulation in terms of the minimal Sullivan model of X. We study another such numerical invariant called the rational retraction index of X, denoted r0(X), which is defined in terms of the minimal Sullivan model of X and satisfies 0 ≤ r0(X) ≤ cat0(X). It was introduced by Cuvilliez et al. as a tool to estimate the rational Lusternik–Schnirelmann category of the total space of a fibration. In this thesis we compute the rational retraction index on a range of rationally elliptic spaces, including for example spheres, complex projective space, the biquotient Sp(1) \ Sp(3) / Sp(1) × Sp(1), the homogeneous space Sp(3)/U(3) and products of these. In particular, we focus on formal spaces and formulate a conjecture to answer a question posed in the original article of Cuvilliez et al., “If X is formal, what invariant of the algebra H∗(X;Q) is r0(X)?”
8
Yeung, R. Kacheong. "Stable rational interpolation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0021/NQ46952.pdf.
Full text
9
Barnes, David James. "Rational Equivariant Spectra." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486771.
Full text
10
Hirsch, Benjamin. "Programming rational agents." Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415743.
Full text
11
Reyzin, Alissa Natanovna. "Rational secret sharing." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/46511.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 59-60).
Recent work has attempted to bridge the fields of Cryptography and Game Theory in order to create more robust protocols that allow for a variety of player types. A keystone functionality used in cryptography is Secret Sharing. While there are several well known, efficient protocols that implement Secret Sharing in the Cryptographic model, designing a Rational Secret Sharing protocol which works in the Game Theoretic model has proved challenging. In this thesis, we contrast several recently proposed protocols for Rational Secret Sharing based on their channel models, utility tolerances, equilibrium types, and efficiencies. We also discuss two more general results bridging Cryptography and Game Theory that can be used to construct Rational Secret Sharing protocols. Finally, we highlight several issues of context that influence the ways in which Rational Secret Sharing protocols might be used.
by Alissa Natanovna Reyzin.
M.Eng.
12
Sørensen, Peter Norman. "Rational Social learning." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10833.
Full text
13
Gillies, Anthony S. "Rational belief change." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290412.
Full textAbstract:
We must change our beliefs, and change them in particular ways, in response to new information. But not all changes are created equal: some are rational changes, some not. The Problem of Epistemic Change is the problem of specifying the rational constraints on how the epistemic state of an agent ought to change in the face of new information. This dissertation is about the philosophical and logical investigation of rational belief change. I start by arguing that the familiar foundations---coherence distinction from static epistemology does not adequately carve up the logical space of theories of epistemic change. It is better to think of theories as being loosely ordered along a continuum from more to less foundational. The ordering, however, is "clumpy" in the sense that there are large regions in the ordering which remain unexplored. I then present and develop GDEC which is a new foundations model of belief revision that fills a gap in this ordering of theories of epistemic change. The key insight in GDEC is that belief that...is ambiguous between the attitudes of accept that...and expect that... GDEC respects the difference and how it matters for epistemic change. I show that GDEC is a genuine competitor to the AGM theory of belief revision in the sense that the two approaches are incompatible. The remainder of the dissertation is devoted to exploring the logical dynamics of GDEC and the models I develop here which extend it by applying them to a series of richer epistemic environments. I show how puzzles and paradoxes which confound other theories of belief revision are solved in a unified way by GDEC and its extensions. In particular, I give solutions to Moore's Paradox, Fuhrmann's Impossibility Theorem, the Reduction Problem of Epistemic Conditionals, and the Gardenfors Impossibility Theorem.
14
Steele, Rachael Helen. "Deciding on crime? : rational vs. non-rational elements in offender decision making." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569518.
Full textAbstract:
This study examines the applicability of Rational Choice Theories of offending to offenders' actual offending experiences. The Rational Choice theoretical perspective is premised on the idea of the offender as a reasoning, decision-making individual who weighs up potential costs and benefits of a crime to achieve maximum utility. This approach to crime has been influential as part of the dominant ethos of the contemporary Criminal Justice system in England and Wales, and indeed the justice systems of most Western societies. This study relates the Rational Choice Theories of crime to individual offender experiences to investigate if such a process as a decision making calculus can be said to exist within the experience of offending individuals and if so, to explore any factors identified as affecting these decisions. Previous literature in the application of Rational Choice Theory to crime is reviewed, in particular the previous research that entailed interviews or direct observation of individuals concerning what happens when he or she is about to commit a crime. However the number of relevant studies undertaken with a sample of actual offenders rather than a student or other non offending population is small. Previous studies of this kind have tended to focus on a particular offence type, utilising for example all burglar or all shoplifter samples, and therefore results and conclusions reached by these studies can be difficult to generalise to other offence types, though there is some overlap in findings. Within the present study, in depth interviews were conduced with 46 offenders with a range of offending experiences. In this way, the study aimed to assess the applicability of the Rational Choice Theories to a range of offending decisions, bringing together different offences from shoplifting to violent assault. Women were deliberately oversampled relative to the percentage of women in the offending population in order to ensure a balanced viewpoint on decision making. In using a diverse sample group it was proposed that the concepts and ideas emerging from the diverse group could contribute to further development of the Rational Choice approach to crime. To support this theoretical development interview narrative was analysed using techniques adapted from Grounded Theory in order to identify the themes and concepts introduced by the offending individuals in relation to their experiences. In addition to the interviews, focus groups were conducted with a separate cohort of offenders and a cohort of experienced members of Probation Service staff in order to examine the prevalence of the themes emerging from the interviews. Offender narrative was also checked against an independent overview of the offending incident in question to establish the level of accuracy in terms of the observable facts of the offence. The results of this research suggest that there is some evidence that some offenders engage in a decision making processes prior to an offence, though evidence of rationality can be seen to vary both within and between individuals and within and between offence types. Where a decision making calculus was observed, several themes emerged from the narrative, including the bias towards focusing thought on potential positive outcomes, the relative lesser weighting of potential negative outcomes in the thought process, and the relative importance of informal sanctions over formal sanctions. The impact of alcohol and drugs was another emerging theme, with offenders describing their substance use as both an inhibiter, and enabler to their thinking processes. Further, an overarching theme to emerge was the evidence for two goal-regulation type processes identified by the offenders as the main motivator of their behaviour. The first of these is the desire to achieve a want or need through the commission of an offence, which tended to be associated with acquisitive category offences (shoplifting, burglary etc) and the second being to avoid or gain relief from an unpleasant affective state or situation, which tended to be associated with affective or expressive offences. However, despite these process -offence type associations there were once again variances observed within individuals and within offence types. That is, an individual could be seen as offending based on both goal types at different times, and even offence types that appear similar can be a result of different goal seeking processes. Suggestions are made as to how the findings and conclusions of this study fit with, and allow development of existing Rational Choice approaches to crime, and advocate the use of the developed Rational Choice Approach as a tool for the study of individual thinking in the period surrounding an offence. A 'Decision Structure' model based on this developed Rational Choice approach is described, with emphasis on the personal, social and motivational factors present at the time of the offence, providing a framework for exploring the offending decision. Implications of this 'Decision Structure' model on the study of offending and on working with offenders are suggested, and ideas for further studies are presented.
15
Prendergast, Arthur Edward. "Extremal rational elliptic threefolds." Thesis, University of Cambridge, 2009. https://www.repository.cam.ac.uk/handle/1810/252154.
Full text
16
Stepp, Todd Alan. "Scriptural and rational piety." 24-page ProQuest preview, 2007. http://proquest.umi.com/pqdweb?index=0&did=1375508181&SrchMode=1&sid=2&Fmt=14&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1220040920&clientId=10355.
Full text
17
Critchley, Peter Joseph Paul. "Marx and rational freedom." Thesis, Manchester Metropolitan University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341087.
Full text
18
Azar, Pablo Daniel. "Super-efficient rational proofs." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/93052.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-49).
Information asymmetry is a central problem in both computer science and economics. In many fundamental problems, an uninformed principal wants to obtain some knowledge from an untrusted expert. This models several real-world situations, such as a manager's relation with her employees, or the delegation of computational tasks to workers over the internet. Because the expert is untrusted, the principal needs some guarantee that the provided knowledge is correct. In computer science, this guarantee is usually provided via a proof, which the principal can verify. Thus, a dishonest expert will always get caught and penalized. In many economic settings, the guarantee that the knowledge is correct is usually provided via incentives. That is, a game is played between expert and principal such that the expert maximizes her utility by being honest. A rational proof is an interactive proof where the prover, Merlin, is neither honest nor malicious, but rational. That is, Merlin acts in order to maximize his own utility. I previously introduced and studied Rational Proofs when the verifier, Arthur, is a probabilistic polynomial-time machine [3]. In this thesis, I characterize super-efficient rational proofs, that is, rational proofs where Arthur runs in logarithmic time. These new rational proofs are very practical. Not only are they much faster than their classical analogues, but they also provide very tangible incentives for the expert to be honest. Arthur only needs a polynomial-size budget, yet he can penalize Merlin by a large quantity if he deviates from the truth.
by Pablo Daniel Azar.
Ph. D.
19
Chan, Daniel Sai-Ping 1971. "Noncommutative rational double points." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85299.
Full text
20
Ledberg, Emil. "Introduction to rational billiards." Thesis, Uppsala universitet, Tillämpad matematik och statistik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-352389.
Full text
21
Mealand, David L. "Philosophy of rational belief." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/30501.
Full text
22
Riedl, Eric. "Rational Curves on Hypersurfaces." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467233.
Full text
23
DEMEIO, JULIAN LAWRENCE. "Abundance of rational points." Doctoral thesis, Scuola Normale Superiore, 2021. http://hdl.handle.net/11384/109444.
Full textAbstract:
For a smooth algebraic variety X defined over a number field K, one could ask several questions
about the abundance of its rational points.
This thesis revolves, in particular, around the following three properties: Hilbert Property,
weak approximation and strong approximation. The first concerns, more or less, the question of
extending the Hilbert Irreducibility Theorem to an arbitrary X (in the sense that the parameters
of the Theorem are allowed to vary through rational points of this variety), the interesting case
being when X is non-rational, for otherwise one recovers precisely the original theorem of Hilbert.
The other two concern the question of density of rational points of X in the adelic ones (possibly
with some places removed). The adjective weak" is more commonly used when talking about
proper varieties, and the adjective strong" is used otherwise.
In the first original work that is part of this thesis, we prove that, under a technical assumption,
a proper algebraic surface X, with Zariski-dense rational points, that is endowed with two or more
genus 1 fibrations, has the Hilbert Property. This result generalizes an earlier result of Corvaja
and Zannier, who proved the Hilbert Property for the Fermat surface x4 + y4 = z4 + w4. The
technique used is similar to theirs, the main idea being that of transporting rational points around
the surface using the elliptic fibers of the various fibrations.
In the second part of the thesis, we prove that on an arbitrary homogeneous space X, under
some technical assumptions, the étale-Brauer-Manin obstruction is the only one to strong approximation.
This obstruction is obtained by applying the more classical Brauer-Manin obstruction
on all finite étale torsors over X. The proof is basically a reduction to a theorem of Borovoi
and Demarche, who proved that (again under technical assumptions) strong approximation up to
Brauer{Manin obstruction holds on homogeneous spaces with connected stabilizers.
In this part of the thesis we also prove a compatibility result, suggested to be true by work of
Cyril Demarche, between Brauer pairing and the so-called abelianization map, for homogeneous
spaces of the form G=H, with H connected and linear.
Finally, in the third and last part of the thesis, we explore the problem of "ramified descent",
or, in other words, the question of which adelic points of X may be lifted to (a desingularization
of a twist of) a fixed geometrically integral and geometrically Galois cover φ : Y --> X, with
commutative geometric Galois group (although in some parts of the work this commutativity
assumption is not needed). The case where the cover is unramified is already well-studied, and,
therefore, the interest lies in the ramified case (whence the terminology "
amified descent"). We
prove that a certain naturally defined descent set" provides an obstruction to Hasse principle
and weak approximation on X (the main difficulty in proving this lies in showing that rational
points that lie on the branch locus of ' are unobstructed).
Moreover, in analogy with the classical unramied case, we construct a subgroup B' of the
Brauer group of X such that the the descent set associated to ' lies in the Brauer{Manin set
associated to B'. Interestingly enough, the transcendental part of B' may provide a non-trivial
obstruction, contrary to what happens in the unramified case. It seems reasonable to expect that
this B' is the only obstruction to the "ramified descent" problem.
24
Botbol, Nicolas. "Implicitization of rational maps." Paris 6, 2010. http://www.theses.fr/2010PA066266.
Full textAbstract:
Motivated by the interest in computing explicit formulas for resultants and discriminants we focus on the implicitization of hypersurfaces in several contexts. Implicitization means, given a rational map f:A^n-1->A^n, to compute an implicit equation H of the closed image of im(f). This is a classical problem and there are numerous approaches to its solution (cf. SC95 and Co01). However, it turns out that the implicitization problem is computationally difficult. Our approach is based on the use of linear syzygies by means of approximation complexes, following BuJo03, BC05, and Ch06, where they develop the theory for a rational map f:P^n-1->P^n. Approximation complexes were first introduced by Herzog, Simis and Vasconcelos in HSV82 almost 30 years ago. The main obstruction for this approximation complex-based method comes from the bad behaviour of the based locus of f. Thus, it is natural to try different compatifications of A^n-1, that are better suited to the map F, in order to avoid unwanted base points. With this purpose, in this thesis we study toric compactifications T for A^n-1. First, we view T embedded in a projective space. Furthermore, we compactify the codomain inside (P^1)^n, to deal with the case of different denominators in the rational functions defining f. We also approach the implicitization problem considering the toric variety T defined by its Cox ring, without any particular projective embedding. In all this cases, we blow-up the base locus of the map and we approximate the Rees algebra R_IA of this blow-up by the symmetric algebra S_IAMotivés par la recherche de formules explicites pour les résultants et les discriminants, on se concentre sur l'implicitisation des hypersurfaces dans plusieurs contextes. Implicitisation signifie calculer une équation implicite H de l'image fermée \overline\im(f), étant donné une application rationnelle f:A^(n-1)-> A^n. C'est un problème classique et il y a de nombreuses approches (cf. \ SC95 et Co01). Toutefois, il s'avère que le problème d'implicitisation est difficile du point de vue du calcul. Notre approche est basée sur l'utilisation des syzygies linéaires au moyen de complexes d'approximation, en suivant BuJo03, BC05, et Ch06, ou ils développent la théorie pour une application rationnelle f:P^(n-1)-> P^n. Les complexes d'approximation ont d'abord été introduits par Herzog, Simis et Vasconcelos dans HSV il y a presque 30 ans. L'obstruction principale de la méthode des complexes d'approximation vient du mauvais comportement du lieu base de f. Ainsi, il est naturel d'essayer différentes compatifications de A^(n-1), qui sont mieux adaptés à f, afin d'éviter des points base non désirés. A cet effet, dans cette thèse on étudie des compactifications toriques T de A^(n-1). Tout d'abord, on considère T plongée dans un espace projectif. En outre, on compactifie le codomaine dans (1)^n, pour faire face aux cas des dénominateurs différents dans les fonctions rationnelles qui définissent f. On a également abordé le problème implicitisation lorsque la variété torique T est définie par son anneau de Cox, sans un plongement projectif particulier. Dans tous ces cas, on éclate le lieu base de f et on approche l'algèbre de Rees R_IA par l'algèbre symétrique S_IA
25
Su, Zhixu. "Rational homotopy type of manifolds." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3378383.
Full textAbstract:
Thesis (Ph.D.)--Indiana University, Dept. of Mathematics, 2009.Title from PDF t.p. (viewed on Jul 9, 2010). Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 6263. Adviser: James F. Davis.
26
Hanselmann, Markus Andreas. "Rational points on quartic hypersurfaces." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-141630.
Full text
27
Min, Guo-Hua. "Constructive approximation in rational systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0018/NQ37734.pdf.
Full text
28
Treisman, Zachary. "Arc spaces and rational curves /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5780.
Full text
29
Martinie, Sherri L. "Middle school rational number knowledge." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/281.
Full text
30
Conley, Tom. "Towards a rational industrial policy /." Title page, contents and introduction only, 1993. http://web4.library.adelaide.edu.au/theses/09AR/09arc7518.pdf.
Full text
31
Ellis, April L. "Rational Design of Calcium Biosensors." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_diss/25.
Full textAbstract:
Understanding the temporal and spatial changes in calcium concentration has been a difficult endeavor for many years due to the relatively small changes in calcium concentration during messenging events, the rapid changes upon physiological messenging, and the unavailability of fast, efficient, and sensitive sensors to detect calcium changes. In addition, the key factors in calcium binding have yet to be determined due to the metal-metal interactions, cooperativity, and conformational change involved in calcium binding to natural calcium-binding proteins. To overcome these obstacles and to engineer calcium sensors for in vivo studies of calcium signaling events, calcium binding sites have been engineered into Green Fluorescent Protein. The engineered binding sites demonstrate terbium binding affinity from 2-30 ƒÝM and calcium binding affinity from 50-100 ƒÝM. Site 177 demonstrates green fluorescence when expressed in mammalian cells and produces a response to calcium concentration changes when expressed in the cytosol. Addition of the cycle 3 mutations (M153T, V163A, F99S) to Site 177 allowed for increased brightness in the emission of the chromophore but still exhibited calcium response. The second generation Site 1 demonstrates fluorescence response to calcium concentration changes when expressed both in the cytosol and in the endoplasmic reticulum. Addition of M153T and V163A to Site 1 allowed for expression of fluorescent protein at 37 ¢XC in HeLa cells and at 30 ¢XC in bacteria. Site 1-M153T/V163A exhibits chromophore fluorescence response to calcium with a Kd of 100 ƒÝM and competition with Rhodamine-5N produced a calcium Kd of 107 ƒÝM. This designed sensor, Site 1-M153T/V163A is the first demonstration of a designed calcium binding GFP with calcium response measured both in vivo and in vitro.
32
Coward, Daniel R. "Sums of two rational cubes." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320587.
Full text
33
Muroni, Maurizio. "Rational design of artificial enzymes." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/55043/.
Full textAbstract:
Despite the endeavours of many decades, the design of artificial enzymes remains challenging. The work presented here investigates two known molecules as scaffolds for the design of artificial enzymes an 18 amino acids a helical peptide with two disulfide bridges - 'Apoxaldie' able to catalyse the decarboxylation of oxaloacetate, and the 86-amino acid colicin E9 immunity protein (Im9) with four a helices. Apoxaldie was modified such that the active site lysines were substituted by 2,4-diaminobutyric acid in order to increase the proximity of the enzyme active site to the chiral environment of the a helix. The designed peptide ('Apoxaldie-Dab') was synthesized with two different strategies and the correct formation of disulfide bonds was achieved. However, Apoxaldie-Dab did not show the expected activity for the decarboxylation of oxaloacetate. Circular dichroism studies showed a 30% loss of a helicity upon introduction of 2,4- diaminobutyric acid into Apoxaldie which can explain the decrease in activity. In the case of Im9, two series of mutants, constructed around histidine 10 and asparagine 78 respectively, were designed to introduce histidine-based active sites into hydrophobic clefts. Site directed mutagenesis, gene expression and variant protein purification were carried out for ten variant mutants together with the wild type. The secondary structure and thermal stability of each protein were studied and catalytic activities were examined by monitoring the hydrolysis of /-nitrophenol acetate via ultraviolet-visible spectroscopy. The Im9 variant Tm9-W74A/N78H' demonstrated three times more activity compared to Im9, indicating the modification of IM9 to possess a histidine based active site increased activity as hypothesized through its rational design. The initial work of applying directed evolution on Tm9-W74A/N78H' was accomplished by constructing a phage display library. A transition state analogue was synthesised to test screening the expressed library. This method can be further developed to assist the design of Im9-based artificial enzymes.
34
Fink, Julian. "The nature of rational requirements." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527303.
Full text
35
Bartholomew, Ronald Errol. "Teaching, truancy and rational choice." Thesis, University of Buckingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436887.
Full text
36
Lyster, Caroline. "Terminal illness and rational suicide." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123323.
Full textAbstract:
The debate surrounding the legalization of physician-assisted suicide and euthanasia has seen the introduction of a number of new terms in recent years, the most well known among these being "death with dignity." Proponents of legalization would claim that these terms help to illustrate the difference between the actions of terminally or incurably ill individuals and the actions of individuals who typically commit suicide: the former are acting rationally, while the latter are not, suggesting that "death with dignity" is a case of "rational suicide."Margaret Pabst Battin has suggested that five criteria need to be met in order for a suicide to be considered rational. If it is indeed the case that individuals with terminal or incurable illness are acting differently than others who seek suicide, then it seems that these criteria ought to be met in cases of illness but not in other situations. Upon analysis, however, this does not seem to be the case: individuals with terminal or incurable illnesses are not the only ones who can meet the criteria for rational suicide, and this will have consequences for the way that we treat the suicides of non-terminally or incurably ill individuals. Further, some kind of adjustment period seems to be necessary in order to ensure that the criteria are indeed met before we allow access to "death with dignity."Le débat autour de la légalisation de l'euthanasie et du suicide assisté par un médecin a vu l'introduction de plusieurs termes nouveaux au cours des dernières années, la plus connue parmi eux étant «mort avec la dignité.» Les partisans de la légalisation prétendre que ces termes aident à illustrer la différence entre les actions des personnes qui souffrent des maladies qui sont terminale ou incurable, et les actions des individus qui commettent généralement suicide: l'ancien agissent de manière rationnelle, tandis que les dernières ne font pas the le même, suggérant que «la mort avec la dignité» est un cas de «suicide rationnel.»Margaret Pabst Battin a proposé que cinq critères doivent être remplies pour un suicide à être considéré rationnel. Si c'est le cas que les personnes qui souffrent des maladies qui sont terminale ou incurable agissent différemment des autres qui cherchent suicide, il semble que ces critères doivent être remplies en cas de maladie, mais pas dans les autres situations. Sur l'analyse, cependant, cela ne semble pas être le cas: les personnes atteintes de maladies terminales ou incurables ne sont pas les seuls qui peuvent répondre aux critères de suicide rationnel, ce qui aura des conséquences pour la façon dont nous traitons les suicides des autres personnes. En outre, une sorte de période d'adaptation semble nécessaire afin de s'assurer que les critères sont bien remplis avant d'autoriser l'accès à «la mort avec la dignité.»
37
Staats, Charles III. "Rational curves on universal hypersurfaces." Thesis, The University of Chicago, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3638697.
Full textAbstract:
In this thesis, results are presented toward determining the number and dimension of irreducible components of the space of rational curves on a universal hypersurface. First, the question is reduced to classifying the strata of rational curves in projective space that are defined by the isomorphism class of the restriction of certain vector bundles. Partial results are given for describing these strata. Among these is a conjecture that the general stratum should have balanced isomorphism class. The conjecture is proved in a large infinite family of cases; in the course of the proof, a notion of a balanced vector bundle is introduced for reducible curves. Finally, these results are translated to give partial results about the original question.
A concrete picture of a few rational curves on universal hypersurfaces is given in the supplementary file animations.zip.
38
Miserda, AndreÌs Bobenrieth. "Inconsistencies and their rational tracks." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400168.
Full text
39
Liu, Tiankai. "On planar rational cuspidal curves." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90190.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mathematics, 2014.18
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 145-146).
This thesis studies rational curves in the complex projective plane that are homeomorphic to their normalizations. We derive some combinatorial constraints on such curves from a result of Borodzik-Livingston in Heegaard-Floer homology. Using these constraints and other tools from algebraic geometry, we offer a solution to certain cases of the Coolidge-Nagata problem on the rectifiability of planar rational cuspidal curves, that is, their equivalence to lines under the Cremona group of birational automorphisms of the plane.
by Tiankai Liu.
Ph. D.
40
Rohde, Adam Robert. "Rational Bias In Inflation Expectations." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3093.
Full textAbstract:
Thesis advisor: Robert MurphyWe empirically examine the Biased Expectations Hypothesis, which states that recent price movements in certain sectors play special roles in the formation of in- dividuals inflation expectations. Specifically we analyze whether economists rationally bias their expectations and whether economists and consumers naively bias their ex- pectations with respect to recent inflation in the food and energy sectors. We develop theoretical models for both rationally formed and naively formed inflation expecta- tions. We find that economists do not bias their rationally formed expectations and that consumers and economists do not naively form inflation expectations. Our results do not support the Biased Expectations Hypothesis; rather, they reinforce the use of core measures of inflation in policy making
Thesis (BA) — Boston College, 2013
Submitted to: Boston College. College of Arts and Sciences
Discipline: Economics Honors Program
Discipline: Economics
41
Angelikopoulos, Panagiotis. "Rational design of nanofibrous materials." Thesis, Heriot-Watt University, 2010. http://hdl.handle.net/10399/2346.
Full textAbstract:
Making Carbon nanotubes a functional material for widespread use is a very cumbersome and challenging task. Not only do CNT materials require the tubes to be well dispersed and individualized rather than in bundles but resulting material has much poorer properties than expected due to insufficient load transfer between crossing CNT. This work tries to provide insight and solutions onto both of these problems, by employing computer simulations to reveal the dual nature of surfactant mediated forces on CNT. A generic coarse grain model has been used along with a dissipative particle dynamics thermostat and implicit solvent treatment. Results illustrate that depending on the bulk concentration of surfactants and their geometry, one can control the surfatantmediated forces on tubes being able to trigger both tube gluing or dispersion. Furthermore, an adsorption study elucidating the differences between surfactant adsorption on individual tubes and their bundles has been done. Surfactants follow a superlinear synergetic adsorption isothermon individual tubes,whereas adsorb via a Langmuir mechanism on their bundles. This work provides a solid framework of knowledge and insight regarding the nature of CNT and surfactants interaction and adsorption, providing rational arguments for the design of optimum CNT materials.
42
Jones, Ross Peter. "Orbit surgery of rational maps." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627022.
Full text
43
Ellingsen, Simen Andreas. "Nuclear terrorism and rational choice." Thesis, King's College London (University of London), 2009. https://kclpure.kcl.ac.uk/portal/en/theses/nuclear-terrorism-and-rational-choice(c87cf97b-5be3-4ec3-b660-d8e5c1b7b639).html.
Full textAbstract:
The prospect of nuclear terrorism, terrorist acts with nuclear fission explosives, is analysed by means of rational choice theory, a methodology borrowed from economics which has hitherto not been systematically applied to nuclear terrorism. The methodology allows the formalisation and modelling of key choices faced by both the aspiring nuclear terrorist and a potential target government in order to work out best strategies under the assumptions that the players are rational and intelligent. Four relevant decision situations are studied: The terrorist's choice of whether to embark on an ambitious and expensive nuclear project or to stay with tried and trusted conventional methods; The choice of fissile material for a terrorist bent on building a nuclear weapon: highly enriched uranium (HEU) and plutonium as fissile material; The government's choice of prioritising between branches of fissile materials safeguards (HEU versus plutonium); and the strategic interplay between terrorist and government in the case where the terrorist has acquired a nuclear weapon and must decide whether to use it to attack, for extortion (blackmail) or to deter an attack upon his own interests. Several key conclusions reached are of direct policy applicability. A simple decision theoretical analysis shows that heavy emphasis on HEU over plutonium in safeguards measures is justified. It is demonstrated that relative deterrence (by denial) of nuclear terrorism in favour of conventional means is possible, and the conditions for which are found. It is found, moreover, that to use an acquired nuclear weapon for blackmail or deterrence purposes is almost never preferable for a terrorist, and the best response of a government to an explicit nuclear terrorist threat is almost always forceful response.
44
Kaliszczak, Maciej. "Rational design of pyrrolobenzodiazepine derivatives." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4923.
Full textAbstract:
Pyrrolobenzodiazepine (PBD) derivatives interact with the minor-groove of DNA to form mono-adducts (monomers) or cross-links (dimers). They show remarkable activity in vitro and in vivo in a wide range of tumour types and one dimer, SJG-136 is currently in clinical development. Preclinical studies have shown that SJG-136 is a P-gp substrate limiting its anti-tumour activity. The work presented in this thesis identifies key physicochemical properties influencing both the interaction of PBDs with ABC transporters P-gp, MRP1 and BCRP and their growth inhibitory potency. A testable hypothesis for further optimisation of PBDs is proposed. The biological activity of 4 dimers and 12 monomers was assessed using several in vitro models presenting differential expression of ABC transporters. Biological endpoints were the growth inhibitory effect determined using a sulforhodamine B assay and γ-H2AX foci formation. In addition PBD transport was evaluated using a Caco-2 transwell assay. P-gp substrate specificity was restricted to dimers. The MW, the number of (N+O) atoms (>8), a polar surface area (>75 Ǻ2) and hydrogen bonding energy (>10) could discriminate substrates among the PBDs. P-gp polymorphism was also evaluated. The mutation in position 2677 (G/T) was associated with reduced sensitivity to the PBDs. When combined mutations in position 3435/2677 were linked, the transporter abrogated this apparent gain of function. The impact of MRP1 was identified for all dimers and 1/12 monomers. In addition, the cooperative role of glutathione in the resistance mediated by MRP1 to the PBDs was revealed. The presence of a carbonyl moiety at the extremity was shown to discriminate the 7 substrate for MRP1 among the monomers. A structure-activity-relationship study showed that negatively charged (N+O) atoms and a greater number of aromatic rings confer greater dependency to BCRP. BCRP polymorphism was also evaluated. The T482 mutant was associated with an increase in drug transport. The cytotoxicity of the PBDs correlated to the interaction of the DNA as measured by ΔTm. Compounds, being non surface active, with a greater polar surface area and number of aromatic rings and a lower solvent accessible surface area were associated with a greater cytotoxicity. Van-der-waals energy and the electrostatic forces were identified in silico as predictable features involved in the DNA binding. New PBDs were designed and were predicted to be associated with a greater affinity for DNA and with minimal interaction with ABC transporters.
45
Undrakh, Batzorig. "Rational dilation and constrained algebras." Thesis, University of Newcastle upon Tyne, 2018. http://hdl.handle.net/10443/4052.
Full textAbstract:
If a set is a spectral set for an operator T, is it necessarily a complete spectral set? That is, if the spectrum of T is contained in , and von Neumann's inequality holds for T and rational functions with poles o of , does it still hold for all such matrix valued rational functions? Equivalently, if is a spectral set for T, does T have a dilation to a normal operator with spectrum in the boundary of ? This is true if is the disk or the annulus, but has been shown to fail in many other cases. There are also multivariable versions of this problem. For example, it is known that rational dilation holds for the bidisk, though it has been recently shown to fail for a distinguished variety in the bidisk called the Neil parabola. The Neil parabola is naturally associated to a constrained subalgebra of the disk algebra, as are many other distinguished varieties. We show that the rational dilation fails on certain distinguished varieties of the polydisk DN associated to the constrained subalgebra AB := C + B(z)A(D). Here A(D) is the algebra of functions that are analytic on the open unit disk D and continuous on the closure of D, and B(z) is a nite Blaschke product of degree N 2. To this end we identify and study the set of test functions B for H1 B := C+B(z)H1(D). Among others, we show that B is minimal (in a sense that there is no proper closed subset of B is su ces).
46
Simmons, David. "Random Iteration of Rational Functions." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115157/.
Full textAbstract:
It is a theorem of Denker and Urbański that if T:ℂ→ℂ is a rational map of degree at least two and if ϕ:ℂ→ℝ is Hölder continuous and satisfies the “thermodynamic expanding” condition P(T,ϕ) > sup(ϕ), then there exists exactly one equilibrium state μ for T and ϕ, and furthermore (ℂ,T,μ) is metrically exact. We extend these results to the case of a holomorphic random dynamical system on ℂ, using the concepts of relative pressure and relative entropy of such a system, and the variational principle of Bogenschütz. Specifically, if (T,Ω,P,θ) is a holomorphic random dynamical system on ℂ and ϕ:Ω→ ℋα(ℂ) is a Hölder continuous random potential function satisfying one of several sets of technical but reasonable hypotheses, then there exists a unique equilibrium state of (X,P,ϕ) over (Ω,Ρ,θ).
47
Morozov, Vasily A. "Rational design of synthetic metalloproteins." Bowling Green State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1363449087.
Full text
48
Render, Elaine. "Rational monoid and semigroup automata." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/rational-monoid-and-semigroup-automata(0aff0c17-b6f9-4bc8-95d1-ff98da059d42).html.
Full textAbstract:
We consider a natural extension to the definition of M-automata which allows the automaton to make use of more of the structure of the monoid M, and by removing the reliance on an identity element, allows the definition of S-automata for S an arbitrary semigroup. In the case of monoids, the resulting automata are equivalent to valence automata with rational target sets which arise in the theory of regulated rewriting. We focus on the polycyclic monoids, and show that for polycyclic monoids of rank 2 or more they accept precisely the context-free languages. The case of the bicyclic monoid is also considered. In the process we prove a number of interesting results about rational subsets in polycyclic monoids; as a consequence we prove the decidability of the rational subset membership problem, and the closure of the class of rational subsets under intersection and complement. In the case of semigroups, we consider the important class of completely simple and completely 0-simple semigroups, obtaining a complete characterisation of the classes of languages corresponding to such semigroups, in terms of their maximal subgroups. In the process, we obtain a number of interesting results about rational subsets of Rees matrix semigroups.
49
Taber, Peter Addison, and Peter Addison Taber. "Rational Enchantment: Instituting Ecuadorian Biodiversity." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625380.
Full textAbstract:
An increasing concern for biodiversity loss transformed politics and society in Ecuador beginning in the late 1980s. Amidst a proliferation of expert work to gain new knowledge of what biodiversity existed where in order to curb species extinctions, both the state of biological science and the way that Ecuador was governed were remade. To examine the institution of biodiversity and its contemporary consequences in Ecuador, this dissertation draws on ethnography with and archival research on a community of botanists connected with Ecuador's National Herbarium. It begins by examining the specialized work that formed the foundation for NGO-led biodiversity conservation. It then looks at the rise of environmental impact assessment used to anticipate and mitigate the impacts of development projects. Finally, the dissertation examines the contemporary dilemmas of Ecuadorian field biologists in the context of the recent dismantling of much of this institutional infrastructure from the last 30 years.
The dissertation's central argument is that biodiversity is an intrinsically modern (and relatively recent) relationship to biological resources, and that it comes with many of the dilemmas and problems that characterize modern institutions. Its emergence as a recognizable domain, either of expert management or more general social commitment, is inextricably bound up with the production of certain forms of specialized knowledge, and the use of that knowledge in authorizing certain kinds of institutional interventions. A mis-recognition of this aspect of biodiversity (for example, by conflating 'biodiversity' with 'biological things themselves') risks misunderstanding what kind of an object it is, to the detriment of anthropological critiques of environmental politics.
50
O'Connell, Robert W. "Pinching deformations of rational maps." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3354918.
Full textAbstract:
Thesis (Ph.D.)--Indiana University, Dept. of Mathematics, 2009.Title from PDF t.p. (viewed on Feb. 4, 2010). Source: Dissertation Abstracts International, Volume: 70-04, Section: B, page: 2340. Adviser: Kevin M. Pilgrim.