Geóloga / En el presente trabajo se pretende desarrollar una metodología que permita modelar superficies cubiertas a partir de la geomorfología expuesta. Esto se desarrolló en la cuenca Toki, al oeste de la ciudad de Calama, zona que se caracteriza por tener un clima árido y ha permanecido así por al menos 25Ma, lo que ha favorecido la preservación de ciertas geoformas denominadas pediplanos (superficies de bajo relieve). Para lograr el objetivo de generar la superficie de contacto entre basamento-grava bajo un relleno posterior, se utilizaron distintos métodos de interpolación geoestadísticos usando el software ArcGis, tomando como datos de entrada las superficies geomorfológicas (Pediplanos) y superficies con distintos rangos de pendiente. Para poder cuantificar el error del modelo se utilizó como contacto real la información proveniente de 495 sondajes. Los resultados mostraron que los datos de entrada proveniente de las superficies de bajo relieve aportan información relevante que permiten crear un modelo cercano a lo que es la geometría de la superficie real. Una simple selección por pendiente entrega resultados similares a los obtenidos a partir de las geoformas lo que podría permitir automatizar la metodología. Además, una mínima cantidad de información extra (menos de un 10% de sondajes) entrega una buena estimación de dicho contacto minimizando drásticamente los errores. Asimismo, los resultados mostraron que existe una pendiente optima tal que su proyección pase cercana al contacto real. Existe una elección de sondajes basada en una ubicación a cierta distancia que sería óptima para minimizar el error y no existe una clara relación entre el error y la cantidad de datos de entrada, lo que quiere decir que el tipo de información de entrada es crucial para generar un buen modelo predictivo.

El blanco Pulucktur corresponde a un sector cubierto por calizas y sedimentos continentales sub horizontales del Mioceno al Pleistoceno. Se sitúa a 7 km. al suroeste de Calama, en la II Región. En este blanco, entre julio de 2007 y mayo de 2010, se han perforado 3522 m de sondajes diamantinos en 10 pozos con profundidades variables entre 276 y 570 m. El objetivo fue probar el potencial de exploración por un cuerpo mineralizado similar a los pórfidos cupríferos del cercano Cluster Toki [1] en un llano con evidencias, en sondajes previos, de mineralización enriquecida de cobre asociada a pórfidos de composición tonalítica a granodiorítica, en un alineamiento mineralizado de orientación noreste, a unos 3 km. al oeste del cuerpo mineralizado Opache descubierto en 1996. Los resultados más relevantes corresponden a la identificación de un alineamiento de pórfidos mineralizados de unos 300 a 400 m de ancho que se extendería a lo largo de más de 3 km. en dirección NNE y que es interceptado por la mayor parte de los sondajes realizados. Este sector mineralizado se correlaciona espacial y temporalmente con el corredor de pórfidos del “Cluster Toki”, de acuerdo a datación Re-Os en molibdenita de 36.3 ± 0.2 ma. Presenta potencial para mineralización enriquecida en el sector central y potencial para mineralización oxidada e hipógena en el sector sur. El sector norte, sin estar descartado, registra una prioridad menor de exploración, ya que se ha detectado mineralización menos intensa en los pórfidos perforados. La mineralización exótica más relevante corresponde al pozo DDH-2978 que registra 42 m con 0,21% Cu consistente en crisocola y óxidos negros en limos, gravas y primeros metros del sustrato rocoso, por tanto se infiere un aumento de la relevancia de esta mineralización hacia el oeste del sector central del área. El estilo de mineralización de mayor interés económico detectado en el Prospecto corresponde a mineralización enriquecida de calcosina, en el sector centro - occidental de la faja mineralizada (pozos DDH-2978, 2979 y 2990), incluyendo una intersección mineralizada de 52.5 m con 0,41% Cu. El modelo de mineralización más concordante con los resultados obtenidos a la fecha y que es coherente a los antecedentes distritales, corresponde a la presencia de conductos de orientación NNE que controlaron el emplazamiento de pórfidos con mineralización cuprífera asociada y un sistema estructural NW postmineral, que produciría desplazamientos dextrales, exponiendo bloques con distintos niveles de alteración.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Minoru Miki's first two marimba compositions, Time for Marimba (1968) and Concerto for Marimba and Orchestra (1969) were composed at a revolutionary time-period for the marimba. Due to unique and innovative compositional techniques, Miki helped establish the marimba as a true concert instrument capable of performing music of the highest quality. As a pioneer in composing for marimba literature, Miki was able to capture the true essence of the marimba; a timeless quality that has helped Time for Marimba remain a part of the standard solo repertoire for the past forty years. The purpose of this study is to analyze and compare Minoru Miki's compositions, Time for Marimba and Concerto for Marimba and Orchestra. Composed within a year of each other, these works possess similar compositional techniques, and rhythmic and thematic relationships. This thesis includes a formal analysis and detailed comparisons of compositional techniques used in both works. Performance considerations, a brief biographical sketch of Miki and historical significance of Time for Marimba and Concerto for Marimba and Orchestra are also included.

This dissertation explores a family of temporal meanings pertaining to when, as it appears in When the results were negligible, Galdwin asked why; when she was 50, she left him; and Lowe took a 3-1 lead into the 5th when he finally surrendered his first home run of the season. A widely-accepted view is that when used this way functions as a generalpurpose temporal connective, with underspecified semantics reminiscent to after, during or before, which vary depending on the surrounding context. I propose a heavy revision of this particular claim; surrounding contexts do not by themselves determine the temporal interpretation of when, but they function to strengthen the basic meaning already imposed by grammatical features and lexical constraints. The present system provides accounts for several empirical problems related to corpus-based examples which are inconsistent with previous approaches to the semantics of when. A further characteristic of the present study is its cross-linguistic nature. I extend the analysis of when to toki(-ni), the Japanese counterpart to when. Comparing English and Japanese, I argue that the two languages share the fundamental semantic system but employ different sets of triggering factors for the strengthening process. Supporting evidence for my arguments comes from two manuallyculled newstext corpora prepared for this study. Chapter 1 gives an introduction to the phenomena and issues of interest. I address three distinct temporal relations holding between the when- and main clause events. Forward-sequence entails that the when- clause event occurs earlier than the main, as in when the results were negligible, Galdwin asked why. Overlap consists of two clauses that denote overlapping events, as in when she was 50, she left him. Backward-sequence entails that the when- clause event takes place after the main clause event, as in Lowe took a 3-1 lead into the fifth when he finally surrendered his first home run of the season. Discussions in later chapters assume some familiarity to temporal and discourse semantics literature. Chapter 2 has been devoted to providing such background information, including an introduction to Discourse Representation Theory (Kamp and Reyle (1993)) and Two-Component Aspect Theory (Smith (1993, 1997)). For visual presentation of my ideas, I adopt Blackburn & Bos’ (2000) DRS-building scheme. In Chapter 3 I sketch previous analyses on when- sentences and address their empirical problems. I discuss two streams of approaches. Under one view, when commits to placing two eventualities temporally close to each other, without fixing their relative order (Heinëmäki (1978), Ritchie (1979) and Hinrichs (1986)). An implication of this type of proposal is that whenever a when appears, there is little restriction as to which one of the temporal meanings is chosen. Thus, for these authors when is a general-purpose temporal adverbial used without a specific temporal meaning built into it. Alternatively, scholars such as Moens and Steedman (1989) and Sändström (1993) argue that when does not order events temporally; it only adds an implication concerning event consequentiality, namely that the main clause event is a consequence of the when clause event. A major problem common to both approaches is empirical. The former entails that when is vague as to its temporal implications, when in actuality a given when sentence is usually associated with only one of the temporal meanings. The latter approach, on the other hand, is misleading in giving the impression that all when sentences bear a consequential relation: corpus examples in the present study reveal that it is not true. Chapter 4 presents English corpus data collected for this study and an analysis of when- sentences that avoids the problems surrounding the previous approaches, with emphasis on the claim that pragmatic information is fully responsible for rendering the temporal meanings associated with when. I examine this proposal critically and arrive at a hybrid system where grammatical and pragmatic or extra-linguistic informational contents work in tandem. I also discuss DRT construction rules for when and demonstrate my system for some key examples drawn from the corpus. Chapter 5 turns to a cross-linguistic consideration, focusing on Japanese. After reviewing the literature on Japanese toki-ni (“when” lit. time-at) sentences, such as that authored by Yoshimoto and Mori (2003), I discuss Japanese corpus data and argue for one salient difference between the systems in the two languages: the strengthening processes in English tend to allude to pragmatic and extra-linguistic information while those in Japanese are more directly affected by grammatical factors such as tense marking variations and particle-drop. Chapter 6 concludes the study. I mention some remaining issues, for the purpose of suggesting some future avenues of research which the achievement of this study opens up. Two appendices are included at the end of this dissertation. One explains technical details regarding the corpora used in this study. The other is a summary of miscellaneous numerical results I have obtained while I worked on the project. / text

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