178 resultados para Geometrização de Thurston


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Incomplete understanding of three aspects of the climate system—equilibrium climate sensitivity, rate of ocean heat uptake and historical aerosol forcing—and the physical processes underlying them lead to uncertainties in our assessment of the global-mean temperature evolution in the twenty-first century1,2. Explorations of these uncertainties have so far relied on scaling approaches3,4, large ensembles of simplified climate models1,2, or small ensembles of complex coupled atmosphere–ocean general circulation models5,6 which under-represent uncertainties in key climate system properties derived from independent sources7–9. Here we present results from a multi-thousand-member perturbed-physics ensemble of transient coupled atmosphere–ocean general circulation model simulations. We find that model versions that reproduce observed surface temperature changes over the past 50 years show global-mean temperature increases of 1.4–3 K by 2050, relative to 1961–1990, under a mid-range forcing scenario. This range of warming is broadly consistent with the expert assessment provided by the Intergovernmental Panel on Climate Change Fourth Assessment Report10, but extends towards larger warming than observed in ensemblesof-opportunity5 typically used for climate impact assessments. From our simulations, we conclude that warming by the middle of the twenty-first century that is stronger than earlier estimates is consistent with recent observed temperature changes and a mid-range ‘no mitigation’ scenario for greenhouse-gas emissions.

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TOC: Clubs & Organizations…18 / Current Events & Music…30 / Faculty & Staff…33 / Activities & Events… / Honors & Graduation…65 / Graduates…75 / Yearbook Credits…111 / A Thank You…112 YEARBOOK COMMITTEE: Project Director, Vincent Banrey; Asst. Project Director, Catherine Whan; Editors (1986): Maricruz Saunders; (1987): Juan Jimenez, GloryAnn Torres; LAYOUT DESIGNERS: Vincent Banrey, Stephanie Bowen, Yvonne Brown, Jacqui Fernandez, Milton Ferreira, Omar Harris, Cornelius Huskins, Juan Jimenez, Wayne Keane, Richard Massie, Victoria Pamias, Richard Provost, Maricruz Saunders, GloryAnn Torres, Pedro Torres, Joan Walker, Catherine Whan. PHOTOGRAPHERS: John Carrero, Young Baek Choi, Randy Fader-Smith, Milton Ferreira, Roger Ince, Juan Jimenez, Umoja Kwanguvu, Seymour Lerman, Clinton Linton, Richard Provost, Jaidee amsinghani, Maricruz Saunders, Frank Tocco, GloryAnn Torres, Catherine Whan, Alan Young. ARTISTS: Cover Design: Madeline Vega; Endsheets: Oscar "DJ Ozzie" Ramirez; Division Pages: Jose Marti; International LaGuardia: Jacqui Fernandez; Illustrations: Richard Massie, Jacqui Fernandez, Madeline Vega. WRITERS: Yasmin Ahmed, Vincent Banrey, Warren Gardner, Juan Jimenez, Umoja Kwanguvu, Luis Merchant, Victoria Pamias, Richard Provost, Christiana Somerville, GloryAnn Torres, Joan Walker, Catherine Whan. SIGNIFICANT OTHERS: Word Processing: Blanca Arbito, Edward Hollins, Catherine Whan. Vincent Banrey Spread: developed by Blanca Arbito, Edward Hollins and GloryAnn Torres, Jacqui Fernandez, Catherine Whan. Creative Consultant: Edward Hollins. Promotions: George Condors. SPECIAL THANKS TO: Frank and Seymour of Classic Studios; Chuck Lindsey, Photo Workshop Instructor; Ted Schiffman of Taylor Publishing Co.; Dan Horn and Thurston Reyes of LaGuardia Theatre; and the Recreation staff. ALAN BERMAN IN MEMORIAM: Sketch, Tom Fink; Alan Speaking, Brian Gallagher; Remembering Dr. Alan Berman, Tuzyline Allan.

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Let beta be an hyperbolic algebraic integer of modulus greater than 1. Lot A be a finite set of Q[beta] and D-beta = {(a(i), b(i))(igreater than or equal to0) is an element of (A x A)(N) \ Sigma(i=0)(infinity) a(i)beta(-i)}. We give a necessary and sufficient condition for D-beta to be sofic. As a consequence, we obtain a result due to Thurston (see Corollary 1). We also treat the case where the set of digits A is given by the greedy algorithm and study the connection with the beta-shift. (C) 2002 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.

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This paper deals with two aspects of relativistic cosmologies with closed spatial sections. These spacetimes are based on the theory of general relativity, and admit a foliation into space sections S(t), which are spacelike hypersurfaces satisfying the postulate of the closure of space: each S(t) is a three-dimensional closed Riemannian manifold. The topics discussed are: (i) a comparison, previously obtained, between Thurston geometries and Bianchi-Kantowski-Sachs metrics for such three-manifolds is here clarified and developed; and (ii) the implications of global inhomogeneity for locally homogeneous three-spaces of constant curvature are analyzed from an observational viewpoint.

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In a paper presented a few years ago, de Lorenci et al. showed, in the context of canonical quantum cosmology, a model which allowed space topology changes. The purpose of this present work is to go a step further in that model, by performing some calculations only estimated there for several compact manifolds of constant negative curvature, such as the Weeks and Thurston spaces and the icosahedral hyperbolic space (Best space). ©2000 The American Physical Society.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Física - IFT

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Pós-graduação em História - FCLAS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Based on the study of some philosophical schools – such as the Cartesian Racionalism, the Empiricism of Hume and Kant’s Criticism – and of some brief remarks on Mathematics in ancient world – particularly the greek Mathematics – this paper intends to understand how the euclidean ideas have been taken for a long time as a model of how to geometrize and of what Mathematics is.

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A study on means of developing of perception and reading of the form by the conception and development of a Teaching Methodology of Drawing with emphasis in its early stages, its development and application in the initial stages of the Design process, dissecting it as a mental and physical process. We will be addressing the contributions of Geometry as a mean of simplification of the reading and materializing configurations as some pointers for addressing the Drawing teaching in the reported course.

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Una 3-varietà si dice virtualmente fibrata se ammette un rivestimento finito che è un fibrato con base una circonferenza e fibra una superficie. In seguito al lavoro di geometrizzazione di Thurston e Perelman, la generica 3-varietà risulta essere iperbolica; un recente risultato di Agol afferma che una tale varietà è sempre virtualmente fibrata. L’ingrediente principale della prova consiste nell’introduzione, dovuta a Wise, dei complessi cubici nello studio delle 3-varietà iperboliche. Questa tesi si concentra sulle proprietà algebriche e geometriche di queste strutture combinatorie e sul ruolo che esse hanno giocato nella dimostrazione del Teorema di Fibrazione Virtuale.

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This descriptive cross-sectional survey compared the perceptions of public health nursing practitioners, educators and administrators along two dimensions: the importance of community-focused functions in public health nursing and which occupational categories in public health are responsible for those functions. More than 50 percent of the mailed questionnaires that were sent to a systematic stratified nationwide sample of public health nurses were returned. In general, respondents: were female, were in their 40s, received their basic nursing education in baccalaureate programs, had either a baccalaureate or a master's degree, worked in official agencies or schools, and had approximately 14 years of experience in public health with six in their present position.^ Significant differences between practitioners, educators and administrators were found in their perceptions of both the importance of community-focused functions in public health nursing and in which occupational category they indicated as having the major responsibility to perform those functions. Educators and administrators perceived community-focused functions as more important than did practitioners. Overall the occupational category of administrator was indicated as having the major responsibility for performing community-focused functions.^