This dissertation investigates subject expression patterns in Dominican Spanish (DS). In this variety, the null subject constructions associated with Non-Caribbean Spanish co-exist with the widespread use of overt subjects, which are found in specific constructions that are either rare or unattested in other Spanish varieties. Interestingly, these structures co-exist in the Dominican grammar with the null subject constructions associated with Non-Caribbean Spanish. While subject expression has been studied in a number of Spanish dialects within the generative and the variationist paradigms, monolingual Dominican Spanish, to the best of my knowledge, has not been investigated in previous variationist work. This study covers this gap by examining a large corpus of spontaneous speech (N=6005) gathered in the capital city of Santo Domingo and a rural area in the northwestern Cibao region. Furthermore, in line with the cohesive approach to syntactic variation developed in recent work (Adger and Smith 2005), theoretical implications are drawn from quantitative results. The results obtained in this study show that null and overt subject patterns in DS are regulated by the same constraints that have been found relevant in previous variationist work, i.e. discourse-related factor groups and Person (Otheguy, Zentella and Livert, 2007). These results depart from previous work in that evidence for language change in progress has been found in subject position patterns, rather than in null and overt subject distribution. When this phenomenon is examined, urban, young, high-middle class and female speakers arise as the social groups leading grammatical restructuring. Quantitative and qualitative evidence is taken into account for testing previous syntactic-theoretical proposals on DS. Taking the cartographic approach to syntactic structure (Rizzi 1997) as a point of departure, it will proposed that multiple specifier positions are available within the TP and CP fields to host strong and weak subjects. This proposal, in turn, makes it possible to account for the Null Subject Parameter profile displayed by synchronic DS without resorting to competing grammars in the minds of the speakers.

This dissertation investigates subject expression patterns in Dominican Spanish (DS). In this variety, the null subject constructions associated with Non-Caribbean Spanish co-exist with the widespread use of overt subjects, which are found in specific constructions that are either rare or unattested in other Spanish varieties. Interestingly, these structures co-exist in the Dominican grammar with the null subject constructions associated with Non-Caribbean Spanish. While subject expression has been studied in a number of Spanish dialects within the generative and the variationist paradigms, monolingual Dominican Spanish, to the best of my knowledge, has not been investigated in previous variationist work. This study covers this gap by examining a large corpus of spontaneous speech (N=6005) gathered in the capital city of Santo Domingo and a rural area in the northwestern Cibao region. Furthermore, in line with the cohesive approach to syntactic variation developed in recent work (Adger and Smith 2005), theoretical implications are drawn from quantitative results. The results obtained in this study show that null and overt subject patterns in DS are regulated by the same constraints that have been found relevant in previous variationist work, i.e. discourse-related factor groups and Person (Otheguy, Zentella and Livert, 2007). These results depart from previous work in that evidence for language change in progress has been found in subject position patterns, rather than in null and overt subject distribution. When this phenomenon is examined, urban, young, high-middle class and female speakers arise as the social groups leading grammatical restructuring. Quantitative and qualitative evidence is taken into account for testing previous syntactic-theoretical proposals on DS. Taking the cartographic approach to syntactic structure (Rizzi 1997) as a point of departure, it will proposed that multiple specifier positions are available within the TP and CP fields to host strong and weak subjects. This proposal, in turn, makes it possible to account for the Null Subject Parameter profile displayed by synchronic DS without resorting to competing grammars in the minds of the speakers.

The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nanzi and Siaogang sites in Kaohsiung city. Source apportionment was determined by the factor analysis. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83 £gg/m3) at Nanzi, followed by formaldehyde (5.03 £gg/m3). At Siaogang, the highest concentrations of carbonyls was acetaldehyde (28.91 £gg/m3), followed by formaldehyde (6.92 £gg/m3). The concentrations of total carbonyls was higher at Siaogang (57.86 £gg/m3) than those at Nanzi (49.74 £gg/m3) . The concentrations of total carbonyls at Nanzi were 65.42 £gg/m3 in summer and 25.06 £gg/m3 in winter, and were 85.09 £gg/m3 in summer and 37.12 £gg/m3 in winter at Siaogang, due to the fact that summer has stronger photochemical activities than in winter. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls was higher. The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nanzi and Siaogang sites in Kaohsiung city. Source apportionment was determined by the factor analysis. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83 £gg/m3) at Nanzi, followed by formaldehyde (5.03 £gg/m3). At Siaogang, the highest concentrations of carbonyls was acetaldehyde (28.91 £gg/m3), followed by formaldehyde (6.92 £gg/m3). The concentrations of total carbonyls was higher at Siaogang (57.86 £gg/m3) than those at Nanzi (49.74 £gg/m3) . The concentrations of total carbonyls at Nanzi were 65.42 £gg/m3 in summer and 25.06 £gg/m3 in winter, and were 85.09 £gg/m3 in summer and 37.12 £gg/m3 in winter at Siaogang, due to the fact that summer has stronger photochemical activities than in winter. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls was higher. Source apportionment analysis using factor analysis shows that the principle sources at Nanzi were traffic exhausts (motor, diesel, and gasoline vehicle) and stationary sources (industry, restaurant and chemical processes). The main sources at Siaogang were traffic exhausts (motor and gasoline vehicle), stationary sources (industry and restaurant) and secondary photo-chemical reactions.

The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nan-Chie ¡BHsiung-Kong¡BRen-Wu and Lin-Yuan sites. Factor analysis was also used to determine the source apportionment in the Kaoshiung area. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83, 28.91, 11.46 and 10.06 £gg/m3) at four sites, followed by formaldehyde (5.03, 6.92, 7.88 and 6.59 £gg/m3), respectively. The highest concentration of total carbonyls at Nan-Chie and Hsiung-Kong was 65.42 £gg/m3 and 85.09 £gg/m3 in summer, the lowest concentration was 25.06 £gg/m3 and 37.12 £gg/m3 in winter, relatively, the highest concentration of total carbonyls at Ren-Wu and Lin-Yuan was 49.94 £gg/m3 and 55.24 £gg/m3 in winter, the lowest concentration was 24.48 £gg/m3 and 11.78 £gg/m3 in autumn. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls. The results of factor analysis showed that the principle sources at Nan-Chie were traffic exhausts (diesel and gasoline vehicle) and stationary sources (metal assembly, waste treatment, pulp and restaurant). The principle sources at Hsiung-Kong were traffic exhausts (diesel, and gasoline vehicle), stationary sources (leather, chemical process and restaurant). The main sources at Ren-Wu were traffic exhausts (gasoline vehicle) and stationary sources (metal assembly, chemical process and restaurant). The main sources at Lin-Yuan were traffic exhausts (diesel vehicle) and stationary sources (metal assembly, leather, steel production and restaurant).

Environmental heterogeneity has often been suggested as a general explanation for patterns of diversity at scales ranging from individuals within populations to communities within landscapes. I evaluate this proposition using laboratory experiments with two microbial species, the unicellular chlorophyte Chlamydomonas reinhardtii and the common bacterium Pseudomonas fluorescens. These experiments contrast the fate of diversity following selection in heterogeneous and homogeneous environments. Specifically, I show that (1) an individual's breadth of adaptation evolves to match the amount of environmental variation, specialists evolving in environments that remain constant through time and generalists evolving in environments that vary through time irrespective of the scale at which environmental variation occurs relative to the lifetime of an individual; (2) the maintenance of diversity in a spatially heterogeneous environment is context-dependent, diversity being more readily maintained when environmental conditions are very different and genotypes are widely divergent; (3) selection in heterogeneous environments represents a plausible mechanism for two well-known patterns of diversity at large spatial scales, namely that between species diversity and both productivity and disturbance. This thesis thus demonstrates that environmental heterogeneity is a plausible, and perhaps very general, factor responsible for the diversity of natural communities.

Variability affects the performance and power of a circuit. Along with static variations, dynamic variations, which occur during chip operation, necessitate a safety margin. The safety margin makes it difficult to meet the target performance within a limited power budget. This research explores methodologies to minimize the safety margin, thereby improving the energy efficiency of a system. The safety margin can be reduced by either minimizing the variation or adapting to the variation. This research explores three different methods to compensate for variations efficiently. First, post-silicon tuning methods for minimizing variations in 3D ICs are presented. Design methodologies to apply adaptive voltage scaling and adaptive body biasing to 3D ICs and the associated circuit techniques are explored. Second, non-design-intrusive circuit techniques are proposed for adaptation to dynamic variations. This work includes adaptive clock modulation and bias-voltage generation techniques. Third, design-intrusive methods to eliminate the safety margin are proposed. The proposed methodologies can prevent timing-errors in advance with a minimized performance penalty. As a result, the methods presented in this thesis minimize static variations and adapt to dynamic variations, thereby, enabling robust low-power operation of digital systems.

This dissertation investigates subject expression patterns in Dominican Spanish (DS). In this variety, the null subject constructions associated with Non-Caribbean Spanish co-exist with the widespread use of overt subjects, which are found in specific constructions that are either rare or unattested in other Spanish varieties. Interestingly, these structures co-exist in the Dominican grammar with the null subject constructions associated with Non-Caribbean Spanish. While subject expression has been studied in a number of Spanish dialects within the generative and the variationist paradigms, monolingual Dominican Spanish, to the best of my knowledge, has not been investigated in previous variationist work. This study covers this gap by examining a large corpus of spontaneous speech (N=6005) gathered in the capital city of Santo Domingo and a rural area in the northwestern Cibao region. Furthermore, in line with the cohesive approach to syntactic variation developed in recent work (Adger and Smith 2005), theoretical implications are drawn from quantitative results. The results obtained in this study show that null and overt subject patterns in DS are regulated by the same constraints that have been found relevant in previous variationist work, i.e. discourse-related factor groups and Person (Otheguy, Zentella and Livert, 2007). These results depart from previous work in that evidence for language change in progress has been found in subject position patterns, rather than in null and overt subject distribution. When this phenomenon is examined, urban, young, high-middle class and female speakers arise as the social groups leading grammatical restructuring. Quantitative and qualitative evidence is taken into account for testing previous syntactic-theoretical proposals on DS. Taking the cartographic approach to syntactic structure (Rizzi 1997) as a point of departure, it will proposed that multiple specifier positions are available within the TP and CP fields to host strong and weak subjects. This proposal, in turn, makes it possible to account for the Null Subject Parameter profile displayed by synchronic DS without resorting to competing grammars in the minds of the speakers.

Étudier la liaison et les erreurs enfantines qu’elle entraîne (le nami, un zami) offre une perspective privilégiée sur le développement des représentations lexicales. Des travaux récents (Chevrot, et al., 2007 ; Dugua et al., 2009 ; Chevrot et al., à paraître) ont corroboré un modèle (Chevrot et al., 2009) rendant compte des étapes développementales jalonnant la segmentation des noms précédés d’une liaison. Nous avons mis en place, durant ce doctorat, trois démarches empiriques examinant des hypothèses issues de ce modèle.L’observation de 18094 groupes nominaux déterminant-nom issus d’un corpus de 118 heures de parole adressée à cinq enfants entre 1 et 3 ans fait apparaître trois tendances : 86% contiennent un nom à initiale consonantique (un garçon), la liaison (un ami) n’apparaît que dans 5% des GN, les consonnes enchainées sur l’initiale vocalique des noms sont principalement les liaisons /n/, /z/, /t/ ou le /l/ de l’élision (l’ami). La rareté des liaisons est compatible avec la complexité de leur acquisition. La prévalence des noms à initiale consonantique dans l’input est compatible avec la tendance enfantine à faire correspondre l’initiale du nom avec une consonne et ainsi à produire des segmentations de type /zami/, /nami/ ou /lami/ pour le mot ami. Cette étude aura permis de confirmer une hypothèse sur trois du modèle.Une expérience chronométrique menée chez 60 enfants de 5-6 ans montre que ces derniers ont mémorisé dans leur lexique aussi bien des variantes de type /nami/ et /zarbr/ pour les noms ami et arbre que des séquences fréquentes contenant ces variantes (un-ami, des-arbres). La même étude chez 36 adultes indique ceux-ci mémorisent dans leur lexique des séquences entières, sans retrouver de traces des variantes.Enfin, nous avons exploré l'hypothèse de Morin & Kaye (1982) qui suggéraient un statut particulier à la liaison /z/ : en effet, elle semble pouvoir être inscrite dans notre lexique comme un morphème du pluriel. De ce fait, elle bénéficierait d'un encodage encore plus abstrait, au niveau morphologique.Ces résultats sont discutés dans la perspective des théories basée sur l’usage (Tomasello, 2003) postulant un lexique constitué d’unités de longueurs et de niveaux d’abstraction variables. / Studying the liaison in French and childish mistakes it entails (un nami, un zami) offers a unique perspective on the formation of lexical representations. Recent work (Chevrot and al., 2007; Dugua and al, 2009;.. Chevrot and al, forthcoming) corroborated a model (Chevrot et al., 2009) reflecting the developmental stages during which segmentation of nouns that are preceded by a liaison. We have implemented during this PhD, three empirical approaches to examine the hypotheses which emerge from this model.Observing 18094 déterminant-noun groups from a corpus of 118 hours of speech addressed to five children between 1 and 3 years reveals three trends: 86% contain a noun with an initial consonant (un garçon), the liaison (un ami) appears only in 5% of NG's [for "Noun-Groups"], the consonants which are attached to the initial vowel of nouns are mainly the liaisons / n /, / z /, / t / or the elision / l / (l’ami). The scarcity of the liaison is consistent with the complexity of acquiring it. The prevalence of nouuns with an initial consonant in the input is compatible with children's tendency to match the initial of the name with a consonant and thus to produce segmentations like / zami /, / nami / or / lami / for the word ami. This study has confirmed one of the three hypothesis of the model.A chronometer experiment on 60 5-6 years old children shows that they have stored in their lexicon as well variants like / nami / and / zarbr / for nouns ami and arbre, as frequent sequences containing these variants (un-ami, des-arbres). The same study on 36 adults indicatesthat they store in their lexicon entire sequences, without finding any trace of these variants.Finally, we explored the hypothesis of Morin & Kaye (1982)which suggested that the liaison / z / had a special status : indeed, it seems to be written in our lexicon as a morpheme of the plural form. Therefore, it would benefit from an even more abstract encoding, morphologically.These results are discussed from the perspective of theories based on the common use (Tomasello, 2003) wich states that lexicon consists of units with varying lengths and levels of abstraction.

Introduction: The Chattahoochee River and its lakes and tributaries are essential resources for metro-Atlanta; however, urbanization and other human impacts near these resources affects the quality of water. The objectives of this study are to describe the spatial and temporal patterns of Escherichia coli (E. coli), and examine the relationship between rainfall and E. coli levels in metro-Atlanta surface waters, including the Chattahoochee River and its lakes and tributaries. Methods: The water quality data used for the study was originally collected and analyzed by the Chattahoochee Riverkeeper (CRK) Neighborhood Water Watch (NWW) program. For this analysis, sites with a total of 50 samples or more were subjected to descriptive analysis. Results: Twenty-seven of the 36 sites had a mean E. coli concentration exceeding the US EPA’s recreational water quality criteria of 2.37 log Most Probable Number per 100 milliliters. Sites with the highest and lowest mean E. coli levels were located, on average, 2.77 and 20.22 miles from downtown Atlanta, respectively. Spikes in E. coli levels occurred 99 counts of 699 sampling events in the winter, 168/827 spring, 141/877 summer, and 170/950 fall. Seven of the 36 sites were analyzed to examine the relationship between 48-hour rainfall and E. coli levels. Four sites indicated that there was a significant positive correlation between the two variables. (r=0.52, p<.0001; r=0.67, p<.0001; r=0.39, p<.0001; r=0.38, p<.0001) Discussion: The water quality in waterways closer to downtown may be attributable to combined sewer overflows and the urbanization and land use associated with the city. Overall, there was temporal variation in E. coli concentrations, however there was no distinct seasonal pattern. The relationship between 48-hour rainfall and E. coli levels of four of the seven sites analyzed was consistent with other studies.

This dissertation investigates subject expression patterns in Dominican Spanish (DS). In this variety, the null subject constructions associated with Non-Caribbean Spanish co-exist with the widespread use of overt subjects, which are found in specific constructions that are either rare or unattested in other Spanish varieties. Interestingly, these structures co-exist in the Dominican grammar with the null subject constructions associated with Non-Caribbean Spanish. While subject expression has been studied in a number of Spanish dialects within the generative and the variationist paradigms, monolingual Dominican Spanish, to the best of my knowledge, has not been investigated in previous variationist work. This study covers this gap by examining a large corpus of spontaneous speech (N=6005) gathered in the capital city of Santo Domingo and a rural area in the northwestern Cibao region. Furthermore, in line with the cohesive approach to syntactic variation developed in recent work (Adger and Smith 2005), theoretical implications are drawn from quantitative results. The results obtained in this study show that null and overt subject patterns in DS are regulated by the same constraints that have been found relevant in previous variationist work, i.e. discourse-related factor groups and Person (Otheguy, Zentella and Livert, 2007). These results depart from previous work in that evidence for language change in progress has been found in subject position patterns, rather than in null and overt subject distribution. When this phenomenon is examined, urban, young, high-middle class and female speakers arise as the social groups leading grammatical restructuring. Quantitative and qualitative evidence is taken into account for testing previous syntactic-theoretical proposals on DS. Taking the cartographic approach to syntactic structure (Rizzi 1997) as a point of departure, it will proposed that multiple specifier positions are available within the TP and CP fields to host strong and weak subjects. This proposal, in turn, makes it possible to account for the Null Subject Parameter profile displayed by synchronic DS without resorting to competing grammars in the minds of the speakers.