944 resultados para Algèbres de Lie simples


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Gran parte de los circuitos integrados de aplicación específica actuales se desarrollan sobre dispositivos lógicos programables (PLD). Los fabricantes ofrecen diferentes tecnologías programables, algunas de ellas admiten la reconfiguración de los diseños, incluso en tiempo de operación, mientras que otras pueden configurarse una única vez (tecnologías fusibles y antifusibles). En el trabajo se analizarán las diferentes familias de dispositivos y sus tecnologías, con especial atención en su capacidad de integración y consumo. Asimismo se realizarán diseños simples con alguna de ellas.

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Mandato imperativo -- Systemas eleitoraes : escrutinio de lista por simples maioria, voto uninominal, por districtos de um representante, voto limitado, ou lista incompleta, voto uninominal, com circulo unico, voto cumulativo, escrutinio de lista, com voto transferivel -- Appendice : eleição presidencial : Andorra, Argentina, Bolivia, Chile, Columbia, Costa Rica, Equador, Estados Unidos, França, Guatemala, Haiti, Honduras, Liberia, Mexico, Nicaragua, Paraguay, Orange, Peru, Salvador, São Domingos, São Marinho, Suissa, Uruguay, Venezuela -- O systema de dous turnos no Congresso : projecto n. 121 de 1894, como foi votado pelo Senado -- Carta explicativa para o Ilmo. Dr. J. J. Rodrigues de Freitas Porto / J. F. de Assis Brasil.

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Totalizando 345 questões, totalmente reformuladas em relação à primeira edição de 2002, procura usar linguagem simples para traduzir os principais institutos, regras e costumes da prática parlamentar e do processo legislativo no âmbito da Câmara dos Deputados.

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Este boletim, elaborado pela Consultoria de Orçamento e Fiscalização Financeira da Câmara dos Deputados (Conof), elenca as principais séries históricas e outras informações relacionadas à gestão do orçamento da União no período de 2000 a 2014. O objetivo é disponibilizar aos parlamentares e à sociedade, de forma simples e sintética, os principais parâmetros, resultados fiscais, receitas e despesas previstas e realizadas na lei orçamentária anual (LOA) dos últimos anos.

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The aim of this paper is to propose a new solution for the roommate problem with strict preferences. We introduce the solution of maximum irreversibility and consider almost stable matchings (Abraham et al. [2])and maximum stable matchings (Ta [30] [32]). We find that almost stable matchings are incompatible with the other two solutions. Hence, to solve the roommate problem we propose matchings that lie at the intersection of the maximum irreversible matchings and maximum stable matchings, which are called Q-stable matchings. These matchings are core consistent and we offer an effi cient algorithm for computing one of them. The outcome of the algorithm belongs to an absorbing set.

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The condensation of phenanthroline-5,6-dione (phendione) with polyamines is a versatile synthetic route to a wide variety of chelating ligands. Condensation with 2,3- napthalene diamine gives benzo[i]dipyrido[3,2-a:2',3'-c]phenazine (bdppz) a ligand containing weakly-coupled orbitals of benzophenazine (bpz) and 2,2' -bipyridinde(bpy) character. The bpy character gives Re and Ru complexes excited-state redox properties; intramolecular electron transfer (ET) takes place to the bpz portion of the ligand. The charge-separated state so produced has an extraordinarily-long 50 µs lifetime. The slow rate of charge recombination arises from a combination of extremely weak coupling between the metal center and the bpz acceptor orbital and Marcus "inverted region" behavior. Molecular orbital calculations show that only 3% the electron density in the lowest unoccupied molecular orbital lies on the bpy atoms of bdppz, effectively trapping the transferred electron on the bpz portion. The rate of charge recombination decreases with increasing driving force, showing that these rates lie in the inverted region. Comparison of forward and back ET rates shows that donor-acceptor coupling is four orders of magnitude greater for photoinduced electron transfer than it is for thermal charge recombination.

Condensation of phendione with itself or tetramines gives a series of binucleating tetrapyridophenazine ligands of incrementally-varying coordination-site separation. When a photoredox-active metal center is attached, excited-state energy and electron transfer to an acceptor metal center at the other coordination site can be studied as a function of distance. A variety of monometallic and homo- and heterodimetallic tetrapyridophenazine complexes has been synthesized. Electro- and magnetochemistry show that no ground-state interaction exists between the metals in bimetallic complexes. Excited-state energy and electron transfer, however, takes place at rates which are invariant with increasing donor-acceptor separation, indicating that a very efficient coupling mechanism is at work. Theory and experiment have suggested that such behavior might exist in extended π-systems like those presented by these ligands.

Condensation of three equivalents of 4,5-dimethyl-1,2-phenylenediamine with hexaketocyclohexane gives the trinucleating ligand hexaazahexamethyltrinapthalene (hhtn). Attaching two photredox-active metal centers and a third catalytic center to hhtn provides means by which multielectron photocatalyzed reactions might be carried out. The coordination properties of hhtn have been examined; X-ray crystallographic structure determination shows that the ligand's constricted coordination pocket leads to distorted geometries in its mono- and dimetallic derivatives.

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Oxygen isotopes were measured in mineral separates from martian meteorites using laser fluorination and were found to be remarkably uniform in both δ18O and Δ17O, suggesting that martian magmas did not assimilate aqueously altered crust regardless of any other geochemical variations.

Measurements of Cl, F, H, and S in apatite from martian meteorites were made using the SIMS and NanoSIMS. Martian apatites are typically higher in Cl than terrestrial apatites from mafic and ultramafic rocks, signifying that Mars is inherently higher in Cl than Earth. Apatites from basaltic and olivine-phyric shergottites are as high in water as any terrestrial apatite from mafic and utramafic rocks, implying the possibility that martian magmas may be more similar in water abundance to terrestrial magmas than previously thought. Apatites from lherzolitic shergottites, nakhlites, chassignites, and ALH 84001 (all of which are cumulate rocks) are all lower in water than the basaltic and olivine-phyric shergottites, indicating that the slow-cooling accumulation process allows escape of water from trapped melts where apatite later formed. Sulfur is only high in some apatites from basaltic and olivine-phyric shergottites and low in all other SNCs from this study, which could mean that cumulate SNCs are low in all volatiles and that there are other controlling factors in basaltic and olivine-phyric magmas dictating the inclusion of sulfur into apatite.

Sulfur Kα X-rays were measured in SNC apatites using the electron probe. None of the peaks in the SNC spectra reside in the same position as anhydrite (where sulfur is 100% sulfate) or pyrite (where sulfur is 100% sulfide), but instead all SNC spectra peaks lie in between these two end member peaks, which implies that SNC apatites may be substituting some sulfide, as well as sulfate, into their structure. However, further work is needed to verify this hypothesis.

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Nivel educativo: Grado. Duración (en horas): Más de 50 horas

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Nivel educativo: Grado. Duración (en horas): Más de 50 horas

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A standard question in the study of geometric quantization is whether symplectic reduction interacts nicely with the quantized theory, and in particular whether “quantization commutes with reduction.” Guillemin and Sternberg first proposed this question, and answered it in the affirmative for the case of a free action of a compact Lie group on a compact Kähler manifold. Subsequent work has focused mainly on extending their proof to non-free actions and non-Kähler manifolds. For realistic physical examples, however, it is desirable to have a proof which also applies to non-compact symplectic manifolds.

In this thesis we give a proof of the quantization-reduction problem for general symplectic manifolds. This is accomplished by working in a particular wavefunction representation, associated with a polarization that is in some sense compatible with reduction. While the polarized sections described by Guillemin and Sternberg are nonzero on a dense subset of the Kähler manifold, the ones considered here are distributional, having support only on regions of the phase space associated with certain quantized, or “admissible”, values of momentum.

We first propose a reduction procedure for the prequantum geometric structures that “covers” symplectic reduction, and demonstrate how both symplectic and prequantum reduction can be viewed as examples of foliation reduction. Consistency of prequantum reduction imposes the above-mentioned admissibility conditions on the quantized momenta, which can be seen as analogues of the Bohr-Wilson-Sommerfeld conditions for completely integrable systems.

We then describe our reduction-compatible polarization, and demonstrate a one-to-one correspondence between polarized sections on the unreduced and reduced spaces.

Finally, we describe a factorization of the reduced prequantum bundle, suggested by the structure of the underlying reduced symplectic manifold. This in turn induces a factorization of the space of polarized sections that agrees with its usual decomposition by irreducible representations, and so proves that quantization and reduction do indeed commute in this context.

A significant omission from the proof is the construction of an inner product on the space of polarized sections, and a discussion of its behavior under reduction. In the concluding chapter of the thesis, we suggest some ideas for future work in this direction.

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Laburpena: Bost urteko gela batean burututako ikerketa lan honen bidez, gure inguruko eskoletan ohikoa den egoera aztertu nahi da. Hots, eskoletan ematen diren gatazka egoerak, hain zuzen ere. Gainera, argi izan behar dugu hauek ondo bideratzen ez badira biolentzia edota agresibitate egoerak bilakatu daitezkeela. Gatazka hauek bi eratan ulertu daitezke: alde batetik, umearen jokabide negatibo gisa; edota, gaiaren inguruko hausnarketa sakona eginez gero, umeak ingurunea ulertzeko eta horrekin interakzioak egiteko erabiltzen dituen ikasketa mekanismo gisa. Argi dago beraz, gatazka hauen izaera parametro ezberdinek osatzen dutela: irakaslearen papera, eskainitako baliabideak, umearen garapena, etab. Ikuspuntu honetatik lanean ikasgelan bizi izandako gatazken ezaugarrien frekuentzia erregistroa egin da. Gatazka hauen interpretazioak haur hezkuntzako irakasleei hobetu ulertzen eta honekin batera, hauek era positibo batean bideratzen lagundu ahal dizkie.

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Algorithmic DNA tiles systems are fascinating. From a theoretical perspective, they can result in simple systems that assemble themselves into beautiful, complex structures through fundamental interactions and logical rules. As an experimental technique, they provide a promising method for programmably assembling complex, precise crystals that can grow to considerable size while retaining nanoscale resolution. In the journey from theoretical abstractions to experimental demonstrations, however, lie numerous challenges and complications.

In this thesis, to examine these challenges, we consider the physical principles behind DNA tile self-assembly. We survey recent progress in experimental algorithmic self-assembly, and explain the simple physical models behind this progress. Using direct observation of individual tile attachments and detachments with an atomic force microscope, we test some of the fundamental assumptions of the widely-used kinetic Tile Assembly Model, obtaining results that fit the model to within error. We then depart from the simplest form of that model, examining the effects of DNA sticky end sequence energetics on tile system behavior. We develop theoretical models, sequence assignment algorithms, and a software package, StickyDesign, for sticky end sequence design.

As a demonstration of a specific tile system, we design a binary counting ribbon that can accurately count from a programmable starting value and stop growing after overflowing, resulting in a single system that can construct ribbons of precise and programmable length. In the process of designing the system, we explain numerous considerations that provide insight into more general tile system design, particularly with regards to tile concentrations, facet nucleation, the construction of finite assemblies, and design beyond the abstract Tile Assembly Model.

Finally, we present our crystals that count: experimental results with our binary counting system that represent a significant improvement in the accuracy of experimental algorithmic self-assembly, including crystals that count perfectly with 5 bits from 0 to 31. We show some preliminary experimental results on the construction of our capping system to stop growth after counters overflow, and offer some speculation on potential future directions of the field.

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Die Auswirkungen des milden Winters 1988/89 auf die chemischen und biologischen Prozesse in der Nordsee werden von Fachleuten, aber auch von Politikern und der Presse lebhaft diskutiert. Schon im März wurden Befürchtungen geäußert, eine ähnliche kräftige und eventuell für andere marine Lebewesen schädigende Planktonblüte wie im Vorjahr stünde bevor. Dazu kam es jedoch nicht. Für das Vorjahresereignis wird diskutiert, ob als Grund ein Zusammenwirken von anomaler Zirkulation, kräftiger Frühjahrserwärmung, erhöhtem Festlandabfluß und damit verbundener kräftiger Nährstoffzufuhr in Frage kommt. Eine mögliche Erklärung für die diesjährige "normale" Planktonblüte wäre: Es lag zwar durchaus wieder eine ausgeprägte Zirkulationsanomalie in der Nordsee vor, jedoch fehlte die übermäßige "Düngung" durch Festlandabfluß, da es im vergangenen Frühjahrzu wenig Niederschläge gegeben hatte. Von einer "ganz normalen" Planktonblüte kann man in diesem Jahr allerdings auch nicht sprechen. Das erhöhte winterliche Temperaturniveau ließ einige Planktonarten sich bereits im Februar, also sehr früh, kräftig vermehren.

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The Book of John Mandeville, while ostensibly a pilgrimage guide documenting an English knight’s journey into the East, is an ideal text in which to study the developing concept of race in the European Middle Ages. The Mandeville-author’s sense of place and morality are inextricably linked to each other: Jerusalem is the center of his world, which necessarily forces Africa and Asia to occupy the spiritual periphery. Most inhabitants of Mandeville’s landscapes are not monsters in the physical sense, but at once startlingly human and irreconcilably alien in their customs. Their religious heresies, disordered sexual appetites, and monstrous acts of cannibalism label them as fallen state of the European Christian self. Mandeville’s monstrosities lie not in the fantastical, but the disturbingly familiar, coupling recognizable humans with a miscarriage of natural law. In using real people to illustrate the moral degeneracy of the tropics, Mandeville’s ethnography helps shed light on the missing link between medieval monsters and modern race theory.