Thèse : Sciences. Astronomie : Paris, Faculté des sciences : 1823. / Titre provenant de l'écran-titre.

Thesis (M.S. in Engineering)--University of Texas at Austin, 1976. / Vita. Includes bibliographical references (leaf 109).

Thesis (Ph. D.)--University of Chicago, 1915. / "A Private edition distributed by the University of Chicago Libraries." Reprinted from the Astronomical journal, v. 29, nos. 11-12. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, 1915. / "A Private edition distributed by the University of Chicago Libraries." Reprinted from the Astronomical journal, v. 29, nos. 11-12. Includes bibliographical references. Also available on the Internet.

George Crumb (b.1929)'s Makrokosmos is recognized as one of the masterpieces of twentieth century piano writing. Inexplicably, volume four of Makrokosmos, Crumb's only four-hand piano piece, is rarely studied by Crumb scholars. According to Crumb's program notes, his Makrokosmos is meant to be a hybrid of piano and orchestral sound. Crumb devised a list of signs and abbreviated letters to explain his specific instructions to the performers. The pianists who plan to perform Makrokosmos need to study Crumb's notations carefully in order to faithfully realize the composer's intentions. This dissertation examines the composer's treatment of four hands at the piano. In addition, a performer's analysis and practical "translation" of these techniques is provided, in the hopes of rendering this amazing piece more accessible to pianists in search of new and wonderful repertoire for piano four hands. It is also hoped that future composers will be inspired by Crumb's innovations and imaginative ideas.

The first two observational sky "blocks" of the Outer Solar System Origins Survey (OSSOS) have significantly increased the number of well characterized observed trans-Neptunian objects (TNOs) in Neptune's mean motion resonances. We describe the 31 securely resonant TNOs detected by OSSOS so far, and we use them to independently verify the resonant population models from the Canada-France Ecliptic Plane Survey (CFEPS), with which we find broad agreement. We confirm that the 5:2 resonance is more populated than models of the outer solar system's dynamical history predict; our minimum population estimate shows that the high-eccentricity (e > 0.35) portion of the resonance is at least as populous as the 2:1 and possibly as populated as the 3:2 resonance. One OSSOS block was well suited for detecting objects trapped at low libration amplitudes in Neptune's 3:2 resonance, a population of interest in testing the origins of resonant TNOs. We detected three 3:2 objects with libration amplitudes below the cutoff modeled by CFEPS; OSSOS thus offers new constraints on this distribution. The OSSOS detections confirm that the 2:1 resonance has a dynamically colder inclination distribution than either the 3:2 or 5:2 resonances. Using the combined OSSOS and CFEPS 2:1 detections, we constrain the fraction of 2:1 objects in the symmetric mode of libration to 0.2-0.85; we also constrain the fraction of asymmetric librators in the leading island, which has been theoretically predicted to vary depending on Neptune's migration history, to be 0.05-0.8. Future OSSOS blocks will improve these constraints.

In this dissertation, we examine the nature of embeddings with regard to both combinatorial and geometric configurations. A combinatorial [r,k]-configuration is a collection of abstract points and sets (referred to as blocks) such that each point is a member of r blocks, each block is of size k, and these objects satisfy a linearity criterion: no two blocks intersect in more than one point. A geometric configuration requires that the points and blocks be realized as points and lines within the Euclidean plane. We provide improvements on the current bounds for the asymptotic existence of both combinatorial and geometric configurations. In addition, we examine the largely new problem of embedding configurations within larger configurations possessing regularity properties. Additionally, previously undiscovered geometric [r,k]-configurations are found as near-coverings of combinatorial configurations. / Graduate

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 119-126). Available also in a digital version from Dissertation Abstracts.

We measured the mean plane of the Kuiper Belt as a function of semimajor axis. For the classical Kuiper Belt as a whole (the nonresonant objects in the semimajor axis range 42-48 au), we find a mean plane of inclination i(m) = 1 degrees.8(-0 degrees.4)(+0 degrees.7) and longitude of ascending node Omega(m) = 77 degrees(+18 degrees)(-14 degrees) (in the J2000 ecliptic-equinox coordinate system), in accord with theoretical expectations of the secular effects of the known planets. With finer semimajor axis bins, we detect a statistically significant warp in the mean plane near semimajor axes 40-42 au. Linear secular theory predicts a warp near this location due to the nu(18) nodal secular resonance; however, the measured mean plane for the 40.3-42 au semimajor axis bin (just outside the nu(18)) is inclined similar to 13 degrees to the predicted plane, a nearly 3 sigma discrepancy. For the more distant Kuiper Belt objects of semimajor axes in the range 50-80 au, the expected mean plane is close to the invariable plane of the solar system, but the measured mean plane deviates greatly from this: it has inclination i(m) = 9 degrees.1(-3 degrees.8)(+6 degrees.6) and longitude of ascending node Omega(m) = 277 degrees(+18 degrees)(-44 degrees). We estimate this deviation from the expected mean plane to be statistically significant at the similar to 97%-99% confidence level. We discuss several possible explanations for this deviation, including the possibility that a relatively close-in (a less than or similar to 100 au), unseen, small planetary-mass object in the outer solar system is responsible for the warping.

Orientador: Valério Carruba / Banca: Elbert Nehrer Macau / Banca: Ernesto Vieira Neto / Resumo: Encontros próximos com asteroides massivos são conhecidos por ser um mecanismo de mobilidade dinâmica que pode alterar significativamente elementos próprios de corpos menores, e eles são a principal fonte de mobilidade dinâmica para asteroides médios e grandes dimensões (D>20 km, aproximadamente). A mobilidade orbital causada pelos encontros próximos com asteroides massivos foi estudado no passado e pode ser um mecanismo viável para produzir a localização atual orbital de alguns dos asteroides tipo V atualmente fora da família Vesta. É bem conhecido, no entanto, que as frequências próprias da precessão do pericentro g e longitude do nodo s de planetas terrestres mudam quando um ou mais dos outros planetas não é considerado no esquema de simulação. Por exemplo as frequências g4 e s4 são diferentes quando o sistema solar completo é considerado ou quando somente Marte e os planetas jovianos foram contabilizadas. Neste trabalho consideramos os efeitos de que a inclusão de um ou mais asteroides massivos no esquema de simulação tiver na órbita dos asteroides massivos e, indirectamente, sobre as estatísticas de mudanças no semieixo maior causada pelos encontros próximos com este asteroide massivo. Nós descobrimos que os asteroides massivos, as frequências próprias são dependentes do número de outros asteroides massivos considerados no esquema de simulação e que, como resultado, as estatísticas inteiras do encontros com asteroides massivos também é afetada. As variações da mudança no semieixo maior próprio a causada pelos quatro asteroides mais massivos variou de até 36,3% nos cinco esquemas de simulações que utilizamos, e o número de encontros que causou a fortes mudanças na semieixo maior variou até um fator de 2. O efeito indireto causado pela presença de outros asteroides massivos, portanto... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Close encounters with massive asteroids are known to be a mechanism of dynamical mobility that can significantly alter proper elements of minor bodies, and they are the main source of dynamical mobility for medium-sized and large asteroids (D>20 km, approximately). Orbital mobility caused by close encounters with massive asteroids has been studied in the past and could be a viable mechanism to produce the current orbital location of some of the V-type asteroids currently outside the Vesta family. It is well known, however, that the proper frequencies of precession of pericenter g and longitude of the node s of terrestrial planets change when one or more of the other planets is not considered in the integration scheme. For instance, the g4 and s4 frequencies are different when the full solar system is considered or when only Mars and the Jovian planets are accounted for. In this work we consider the effect that including one or more massive asteroids in the integration scheme has on the massive asteroids orbit, and, indirectly on the statistics of changes in semi-major axis caused by close encounters with this com mais de ummassive asteroid. We find that massive asteroid proper frequencies are dependent on the number of other massive asteroids considered in the integration scheme and that, as a result, the whole statistics of encounters with asteroid is also affected. Variances of the change in proper a caused by the four most massive asteroids varied up to 36.3% in the five integration schemes that we used, and the number of encounters that caused the strongest changes in semi-major axis varied up to a fator 2. The indirect effect caused by the presence of other massive asteroids therefore introduces an additional source of uncertainty in estimating the long-term effect of close encounters with massive asteroids that was not accounted for in... (Complete abstract click electronic access below) / Mestre