This dissertation examines the role of the native dialect in non-native perception and production in the specific case of Cuban and Peninsular Spanish as native varieties and of English vowels as in hat, hut, hot as the target. In most second language studies, the learners’ native variety is assumed to be homogenous, regardless of their regional variety. Nevertheless, regional varieties differ in non-trivial ways and such differences need to be considered when analyzing second language acquisition. This dissertation takes shape around the main research question of whether potentially systematic differences between vowels in the native dialects of Cuban and Peninsular Spanish would produce matching phonetic differences in non-native perception and production of English vowels. This question was addressed in three experiments that compared native vowels in these Spanish varieties, as well as the perception and production of the target English vowels as in hat, hut, hot by Cuban and Peninsular Spanish learners. Significant cross-dialectal differences were identified in the production of native vowels, namely, locations of /i, o/, durations of /e, a, o/ as well as different variability patterns, which were predicted to influence mapping of sounds in L2 perception and production. In L2 perception, discrimination for advanced and naïve listeners from each dialect was tested with English contrasts as in hat-hut, hut-hot, and hat-hot. No clear native dialect effect could be identified; however, Cuban advanced listeners obtained high error rates with hut-hot. In L2 production, though, dialect-specific patterns were found: Peninsular learners produced vowels as in hat, hut, hot with significant spectral but no durational differences whereas Cuban learners produced vowels as in hut, hot with no significant spectral but with duration differences. I concluded that the native dialect was one of several factors generating the differences between Peninsular and Cuban participants’ perception and production of English vowels as in hat, hut, hot. The conjoint effect of the native dialect, input and learning experience were shown to have contributed to the distinctions. This finding contributes to second language acquisition research because it stresses the need to control for learners’ native dialect. This research contributed new acoustic data on Cuban Spanish and on L2 English. It uncovered specific patterns and interlanguage strategies of Spanish learners of English.

This study uses a mixed methods approach to investigate an achievement gap observed in the reading of Canadian-born students with a first language other than English. Quantitative analyses of large-scale reading assessment data identified characteristics of these students and showed a relationship between reading levels and students’ home language environments. This relationship was further explored using a case study approach based on interviews with students and parents. Interviews revealed the role that parental language learning can play in children’s reading. The study revealed the relative invisibility of Canadian-born English language learners, and the consequent difficulties educators have responding to their English language learning needs. School registration data was shown to be an inaccurate indication of students’ home language use. The study’s findings point to the need for policies that support the systematic identification of Canadian-born English language learners and a deeper understanding of the language learning needs of these students-at-risk.

This study uses a mixed methods approach to investigate an achievement gap observed in the reading of Canadian-born students with a first language other than English. Quantitative analyses of large-scale reading assessment data identified characteristics of these students and showed a relationship between reading levels and students’ home language environments. This relationship was further explored using a case study approach based on interviews with students and parents. Interviews revealed the role that parental language learning can play in children’s reading. The study revealed the relative invisibility of Canadian-born English language learners, and the consequent difficulties educators have responding to their English language learning needs. School registration data was shown to be an inaccurate indication of students’ home language use. The study’s findings point to the need for policies that support the systematic identification of Canadian-born English language learners and a deeper understanding of the language learning needs of these students-at-risk.

This dissertation examines the role of the native dialect in non-native perception and production in the specific case of Cuban and Peninsular Spanish as native varieties and of English vowels as in hat, hut, hot as the target. In most second language studies, the learners’ native variety is assumed to be homogenous, regardless of their regional variety. Nevertheless, regional varieties differ in non-trivial ways and such differences need to be considered when analyzing second language acquisition. This dissertation takes shape around the main research question of whether potentially systematic differences between vowels in the native dialects of Cuban and Peninsular Spanish would produce matching phonetic differences in non-native perception and production of English vowels. This question was addressed in three experiments that compared native vowels in these Spanish varieties, as well as the perception and production of the target English vowels as in hat, hut, hot by Cuban and Peninsular Spanish learners. Significant cross-dialectal differences were identified in the production of native vowels, namely, locations of /i, o/, durations of /e, a, o/ as well as different variability patterns, which were predicted to influence mapping of sounds in L2 perception and production. In L2 perception, discrimination for advanced and naïve listeners from each dialect was tested with English contrasts as in hat-hut, hut-hot, and hat-hot. No clear native dialect effect could be identified; however, Cuban advanced listeners obtained high error rates with hut-hot. In L2 production, though, dialect-specific patterns were found: Peninsular learners produced vowels as in hat, hut, hot with significant spectral but no durational differences whereas Cuban learners produced vowels as in hut, hot with no significant spectral but with duration differences. I concluded that the native dialect was one of several factors generating the differences between Peninsular and Cuban participants’ perception and production of English vowels as in hat, hut, hot. The conjoint effect of the native dialect, input and learning experience were shown to have contributed to the distinctions. This finding contributes to second language acquisition research because it stresses the need to control for learners’ native dialect. This research contributed new acoustic data on Cuban Spanish and on L2 English. It uncovered specific patterns and interlanguage strategies of Spanish learners of English.

The objective of the proposed research is to develop a new algorithm for range and Doppler ambiguity resolution in radar detection data using L1 minimization methods for sparse signals and to investigate the properties of such techniques. This novel approach to ambiguity resolution makes use of the sparse measurement structure of the post-detection data in multiple pulse repetition frequency radars and the resulting equivalence of the computationally intractable L0 minimization and the surrogate L1 minimization methods. The ambiguity resolution problem is cast as a linear system of equations which is then solved for the unique sparse solution in the absence of errors. It is shown that the new technique successfully resolves range and Doppler ambiguities and the recovery is exact in the ideal case of no errors in the system. The behavior of the technique is then investigated in the presence of real world data errors encountered in radar measurement and detection process. Examples of such errors include blind zone effects, collisions, false alarms and missed detections. It is shown that the mathematical model consisting of a linear system of equations developed for the ideal case can be adjusted to account for data errors. Empirical results show that the L1 minimization approach also works well in the presence of errors with minor extensions to the algorithm. Several examples are presented to demonstrate the successful implementation of the new technique for range and Doppler ambiguity resolution in pulse Doppler radars.

This study investigated cognitive factors that might influence Chinese EFL learners’ argumentative essay writing in English. The factors that were explored included English (L2) language proficiency, Chinese (L1) writing ability, genre knowledge, use of writing strategies, and working memory capacity in L1 and L2. Data were collected from 136 university students who received a battery of tests in two sessions. The tests consisted of timed essay writing tasks in L1 and L2, post-writing questionnaires for genre knowledge and use of strategies in the writing process, a timed grammaticality judgment task for L2 grammar knowledge, a receptive vocabulary test and a controlled-production vocabulary test for L2 vocabulary knowledge, and working memory span tasks in L1 and L2. Quantitative analyses using correlations, paired-samples t-test, analysis of variance and multiple regression revealed that L2 language proficiency is the most important predictor of L2 writing, followed by genre knowledge and L2 writing strategies. L1 writing ability and working memory capacity have slight impact as explanatory variables for L2 writing performance in the timed essay writing task.

Background: The typical western diet contains foods with modest amounts of lipid oxidation products. Previous work by us and others have demonstrated that mildly oxidized lipids promote a gain in fat mass while highly oxidized lipids decrease fat mass in rodents and triglyceride (TAG) accumulation in 3T3-L1 cells. Adipocyte differentiation is regulated by a key nuclear transcription factor known as PPARγ. Objective: To investigate if the alterations in triglyceride accumulation in 3T3-L1 cells pretreated with oxidized soy oil are due to 1) a change in PPARg DNA interactions 2) changes in the expression of SREBP-1c, PPARg, and/or its target genes. Main Methods: Confluent 3T3-L1 cells were pretreated for 24hours with 0.01% soy oil (SO) which was either unheated (unheated SO) or heated for 3, (3h-SO), 6 (6h-SO), or 9hours (9h-SO). The effect of 24hour soy oil exposure was assessed at several time points throughout the differentiation process. Alterations in PPARg DNA interaction was assessed using a PPARγ transcription factor assay kit while alterations in the expression of genes upstream and downstream of PPARγ was determined by RT-PCR. Primary and secondary products of oxidation within the SO were determined by spectrophotometry. Results: The 6hr-SO contained the greatest concentration of peroxides whereas both the 6hr-SO and 9hr-SO contained a significantly higher concentration of conjugated dienes and aldehydes.Nuclear extracts from 3T3-L1 cells pretreated with 6h-SO demonstrated the greatest reduction in PPARγ DNA binding. Compared to the unheated SO and mildly oxidized 3h-SO, cells treated with the 6h-SO had a significant reduction in SREBP-1c, PPARg, LPL, and GLUT4 expression occurring early in the differentiation process. Variations in the gene expression of 6hr-SO pretreated cells persisted within partially differentiated and mature adipocytes. Conclusions: Pre-treatment of preadipocytes with soy oil heated for ³ 6h greatly decreases the activity of PPARγ in the nucleus and adipogenic gene expression . These changes seen in early differentiation seem to correlate the best with the phenotype of reduced triglyceride accumulation seen in mature adipocytes.

The overall goal of this research was to investigate oxidative stress related changes to the proteomes of 3T3-L1 adipocytes and an inducible CYP2E1 expressing HepG2 cells. Enhanced oxidative stress in hypertrophic adipocytes is associated with metabolic dysregulation and insulin resistance. Because mitochondria generate reactive oxygen species (ROS), we monitored changes to the adipocyte mitochondrial proteome during differentiation and enlargement. We labeled mitochondrial extracts from 3T3-L1 cells that were 0, 4, 7, 10, 14, and 18 days post differentiation with iTRAQ, followed by MS based identification. We found citric acid cycle proteins such as pyruvate carboxylase, citrate synthase, as well as beta-oxidation enzymes; cartinine acyl transferase and long-chain enoyl-CoA hydratase up-regulated from 7 through 18 days post differentiation onset. These data indicate TCA up-regulation for enhanced metabolic and citrate output necessary for lipid synthesis in adipocytes. Paradoxically, the data also show the simultaneous increase in the fatty acid oxidation, indicating a metabolic overdrive state. Biochemical assays showing peaks in ATP and ROS generation in 3 day old adipocytes provide further evidence of this overdrive state. A second peak in ROS generation occurred in 10 day old adipocytes; concurrent ATP generation reduced to near pre-adipocyte levels and this may indicate a metabolic shift that may be responsible for increased oxidative stress in hypertrophic adipocytes. We developed a doxycycline inducible CYP2E1 expressing HepG2 cell line using the pTet-On/pRevTRE expression system to allow greater control and sensitivity in the generation CYP2E1 mediated oxidative stress. Our cell line (RD12) demonstrated stability and tight expression control. After induction, RD12 cells showed 30 percent higher CYP2E1 activity when compared to the constitutive E47 cell line. RD12 cells showed 30 percent greater toxicity than E47 cells and 25 percent less free glutathione when exposed to 20 mM acetaminophen, indicating RD12 cells are more sensitive to the effects reactive intermediates and oxidative stress generated by CYP2E1. We conducted a survey of the toxicity of dietary fatty acids (oleic, linoleic, and palmitic) on HepG2 cells to determine fatty acid doses that induced metabolic changes, but did not cause excessive cell death. The dose of 0.20 mM linoleic and palmitic acid for 48 hours produced low toxicity, but oleic acid actually produced lower toxicity than untreated cells. After exposure cells were treated with a pro-oxidant to determine which fatty acid increased the susceptibility to protein carbonylation. The carbonylated protein isolation procedure indicated the palmitic acid may induce more carbonylation than oleic acid, but greater efficiency in the isolation procedure is required for a confidant determination.

In eukaryotic cells, most proteins in the cytosol and nucleus are degraded via the ubiquitin-proteasome pathway. Ubiquitin is best known for its role in targeting proteins for degradation by the proteasome. Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) is found specifically in central and peripheral neurons, and is responsible for the removal of small peptide fragments from the ubiquitin chain and for co-translational processing of ubiquitin gene products to generate free monomeric ubiquitin. In response to extreme conditions, cells exhibit an up-regulation of heat shock protein (HSP) expression, which contributes to repair and protective mechanisms. Within the HSP family, HSP70 is the major inducible member that protects against cell death. Based on the pharmacologic property of organophosphates as an inhibitor of cholinesterase, it is generally contended that manifestations of organophosphate poisoning, including secretion and muscle fasciculation, stupor, cardiopulmonary collapse, respiratory failure, coma or death, result from accumulation of, and over-stimulation by acetylcholine at peripheral of central synapses. One approach in furthering our understanding on organophosphate poisoning is delineation of its potential protective mechanisms. In this regard, the information on the cellular and molecular mechanisms that underlie organophosphate poisoning has received attention. Our laboratory demonstrated previously that a crucial brain site via which mevinphos (Mev), an organophosphate insecticide of the P=O type, acts is the rostral ventrolateral medulla (RVLM), the medullary origin of premotor sympathetic neurons that are responsible for the maintenance of vasomotor tone. The phasic changes in cardiovascular events over the course of acute Mev intoxication also parallel fluctuations of the ¡§life-and-death¡¨ signals that emanate form the RVLM. Based on a rat model of organophosphate poisoning that provides continuous information on cellular and molecular mechanisms in the RVLM, the present study was undertaken to evaluate whether changes in protein level of UCH-L1 or HSP70 are associated with death arising from Mev intoxication. We also evaluated the efficacy of both of them in the neuroprotection against fatality during Mev intoxication. The first part of this study investigated whether UCH-L1 plays a neuroprotective role at the RVLM, where Mev acts to elicit cardiovascular toxicity. In Sprague-Dawley rats maintained under propofol anesthesia, Mev (960 µg/kg, i.v.) induced a parallel and progressive augmentation in UCH-L1 or ubiquitin expression at the ventrolateral medulla during the course of Mev intoxication. The increase in UCH-L1 level was significantly blunted on pretreatment with microinjection bilaterally into the RVLM of a transcription inhibitor, actinomycin D (5 nmol) or a translation inhibitor, cycloheximide (20 nmol). Compared to artificial cerebrospinal fluid (aCSF) or sense uch-L1 oligonucleotide (100 pmol) pretreatment, microinjection of an antisense uch-L1 oligonucleotide (100 pmol) bilaterally into the RVLM significantly increased mortality, reduced the duration of the phase I (¡§pro- life¡¨ phase), blunted the increase in ubiquitin expression in ventrolateral medulla, and augmented the induced hypotension in rats that received Mev. The second part of this study investigated whether HSP70 plays a neuroprotective role at the RVLM. Intravenous administration of Mev (960

The purpose of this study is to reveal the perceptions of teachers, learners, teacher trainers and administrators on teachers