949 resultados para Numbers, Rational


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It is an exciting era for molecular computation because molecular logic gates are being pushed in new directions. The use of sulfur rather than the commonplace nitrogen as the key receptor atom in metal ion sensors is one of these directions; plant cells coming within the jurisdiction of fluorescent molecular thermometers is another, combining photochromism with voltammetry for molecular electronics is yet another. Two-input logic gates benefit from old ideas such as rectifying bilayer electrodes, cyclodextrin-enhanced room-temperature phosphorescence, steric hindrance, the polymerase chain reaction, charge transfer absorption of donor–acceptor complexes and lectin–glycocluster interactions. Furthermore, the concept of photo-uncaging enables rational ways of concatenating logic gates. Computational concepts are also applied to potential cancer theranostics and to the selective monitoring of neurotransmitters in situ. Higher numbers of inputs are also accommodated with the concept of functional integration of gates, where complex input–output patterns are sought out and analysed. Molecular emulation of computational components such as demultiplexers and parity generators/checkers are achieved in related ways. Complexity of another order is tackled with molecular edge detection routines.

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The aim of this article was to construct a T–ϕ phase diagram for a model drug (FD) and amorphous polymer (Eudragit® EPO) and to use this information to understand the impact of how temperature–composition coordinates influenced the final properties of the extrudate. Defining process boundaries and understanding drug solubility in polymeric carriers is of utmost importance and will help in the successful manufacture of new delivery platforms for BCS class II drugs. Physically mixed felodipine (FD)–Eudragit® EPO (EPO) binary mixtures with pre-determined weight fractions were analysed using DSC to measure the endset of melting and glass transition temperature. Extrudates of 10 wt% FD–EPO were processed using temperatures (110°C, 126°C, 140°C and 150°C) selected from the temperature–composition (T–ϕ) phase diagrams and processing screw speed of 20, 100 and 200rpm. Extrudates were characterised using powder X-ray diffraction (PXRD), optical, polarised light and Raman microscopy. To ensure formation of a binary amorphous drug dispersion (ADD) at a specific composition, HME processing temperatures should at least be equal to, or exceed, the corresponding temperature value on the liquid–solid curve in a F–H T–ϕ phase diagram. If extruded between the spinodal and liquid–solid curve, the lack of thermodynamic forces to attain complete drug amorphisation may be compensated for through the use of an increased screw speed. Constructing F–H T–ϕ phase diagrams are valuable not only in the understanding drug–polymer miscibility behaviour but also in rationalising the selection of important processing parameters for HME to ensure miscibility of drug and polymer.

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This paper deals with identification of dynamics in suction control of airfoils for low Reynolds number regimes (8 x 10^4 - 5 x 10^5). In particular, the dynamics of interest is the map that relates suction pressure and surface pressure. Identification of such dynamics is of use to a variety of active control applications including suction control in small/medium wind turbines which operate in these Reynolds number regimes. Prior research has largely focused on higher Reynolds number regimes, creating a need for such a study. Towards identifying the said dynamic relations, experiments were conducted on NACA0012 airfoil in a wind tunnel. The dynamic relation between suction and surface pressure was identified as an overdamped second order system.

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Heterogeneous catalysis is of great importance both industrially and academically. Rational design of heterogeneous catalysts is highly desirable, and the computational screening and design method is one of the most promising approaches for rational design of heterogeneous catalysts. Herein, we review some attempts towards the rational catalyst design using density functional theory from our group. Some general relationships and theories on the activity and selectivity are covered, such as the Brønsted–Evans–Polanyi relation, volcano curves/surfaces, chemical potentials, optimal adsorption energy window and energy descriptor of selectivity. Furthermore, the relations of these relationships and theories to the rational design are discussed, and some examples of computational screening and design method are given.

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Rational catalyst design is one of the most fundamental goals in heterogeneous catalysis. Herein, we briefly review our previous design work, and then introduce a general optimization framework, which converts catalyst design into an optimization problem. Furthermore, an example is given using the gradient ascent method to show how this framework can be used for rational catalyst design. This framework may be applied to other design schemes.

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The time-dependent close-coupling method is used to calculate electron-impact excitation cross sections for the Li(2s)--{\textgreater}Li(nl) and Li(2p)--{\textgreater}Li(nl) transitions at incident energies just above the ionization threshold. The implementation of the time-dependent close-coupling method on a nonuniform lattice allows the study of continuum-coupling effects in excitations to high principal quantum number, i.e., n{\textless}=10. Good agreement is found with R-matrix with pseudostates calculations, which also include continuum-coupling effects, for excitations to low principal quantum number, i.e., n{\textless}=4. Poor agreement is found with standard distorted-wave calculations for excitations to all principal quantum numbers, with differences still at the 50% level for n=10. We are able to give guidance as to the accuracy expected in the n3 extrapolation of nonperturbative close-coupling calculations of low n cross sections and rate coefficients.

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Relatório de Estágio para obtenção do grau de Mestre em Ensino do 1.º Ciclo do 2.º Ciclo do Ensino Básico. Orientador: Bento Cavadas. Coorientadora:Neusa Branco

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Previous research has shown that lay believers in psychic abilities are more prone to intuitive thinking, less inclined to rational thinking, and have an external locus of control, compared to non-believers. Psychic practitioners, however, may have different characteristics. Psychic practitioners (N=31; mean age = 42.7 years, s.d.=13.1), lay believers (N=33; mean age = 33.0 years, s.d.=10.3), and non-believers (N=31; mean age = 34.4 years, s.d.=15.4) completed questionnaires measuring thinking styles, locus of control, and psychic belief. Comparisons of lay believers with non-believers confirmed previous observations; believers had a higher propensity for intuitive thinking, lower propensity for rational thinking, and more external locus of control. In contrast, practitioners were equivalent to non-believers in rational thinking and had the highest internal locus of control. This highlights the importance of considering level of involvement with psychic practice in understanding the thinking styles of believers. Results suggested that practitioners may have rationalised their beliefs and constructed a coherent model of psychic phenomena that satisfies a propensity for rational thinking within a community of belief.

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This paper presents several combined agricultural data disaggregation models in order to recover the farms' land uses, the livestock numbers and main crops' productions. The proposed approach estimates incomplete information at disaggregated level through entropy, using an information prior, and generating information for a combined calculation use of data in the estimation of other variables. The models were applied to the region of Algarve, to some rural pilot areas (Salir-Ameixial-Cachopo and Alcoutim) for livestock data, since this data in some Algarve's inland areas is needed for a European forest fire prevention project, and to the agrarian zones in a more complex framework. The results are promising. They were validated, in cross reference to real data, having proven to be valid and reliable. The total error was small and a considerable level of information heterogeneity was recovered. The total error was about 27,9% for the counties' land uses and 21% for the agrarian zones, and for the livestock it was also acceptable. The level of heterogeneity recovered was always higher than 50%, revealing some improvements regarding previous studies.

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Relatório da Prática de Ensino Supervisionada, Ensino de Matemática, Universidade de Lisboa, 2013

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Tese de doutoramento, Educação (Didática da Matemática), Universidade de Lisboa, Instituto de Educação, 2014

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Tese de doutoramento, Educação (Didática da Matemática), Universidade de Lisboa, Instituto de Educação, 2016

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The law regulating the availability of abortion is problematic both legally and morally. It is dogmatic in its requirements of women and doctors and ignorant of would-be fathers. Practically, its usage is liberal - with s1(1)(a) Abortion Act 1967 treated as a ‘catch all’ ground - it allows abortion on demand. Yet this is not reflected in the ‘law’. Against this outdated legislation I propose a model of autonomy which seeks to tether our moral concerns with a new legal approach to abortion. I do so by maintaining that a legal conception of autonomy is derivable from the categorical imperative resulting from Gewirth’s argument to the Principle of Generic Consistency: Act in accordance with the generic rights of your recipients as well as of yourself. This model of Gewirthian Rational Autonomy, I suggest, provides a guide for both public and private notions of autonomy and how our autonomous interests can be balanced across social structures in order to legitimately empower choice. I claim, ultimately, that relevant rights in the context of abortion are derivable from this model.