During the production of language, speakers tend to use the same structural patterns from one utterance to the next if it is possible to do so. For example, if a speaker uses a passive or dative construction, he/she is relatively more likely to use the same construction again in the next utterance (e.g., Bock, 1986; Bock & Loebell, 1990; Hartsuiker & Kolk, 1998): the sentence structure "persists".The current study investigates syntactic persistence in first and second language speakers of English and Korean using within-language primes (Experiments 1A, 1B, and 2) and across-language primes (Experiment 3). The target structures were transitive alternate structures (active and passive) and dative alternate structures (double object dative/DAT-ACC dative and prepositional dative/ACC-DAT dative). The experimental paradigm involved repetition of an auditory stimulus, followed by picture description. Overall, syntactic priming effects were found, although various magnitudes were observed as a function of structure; strong effects were found for "shared" syntactic constructions across languages (e.g., active vs. passive) and weak priming effects were found for syntactic constructions not shared (e.g., double object dative vs. prepositional dative) between English and Korean. Other asymmetrical priming effects were observed, reflecting differences between Korean and English such that reliable priming effects were found from L1 to L2, but not from L2 to L1 for Korean-as-L2 speakers (English-as-L1) These patterns of asymmetrical priming imply that cross-linguistic differences might interfere with syntactic persistence in production process unless speakers are highly advanced proficient bilinguals. Also, the present study showed that syntactic priming appears to be sensitive to the order of case-marked phrases in the cross-language priming condition. This finding indicates that the order of case-marked arguments is involved in syntactic repetition. It shed lights on further universal accounts of syntactic priming.

Petroleum hydrocarbons (PHCs) such as gasoline are ubiquitous organic compounds present at contaminated sites throughout the world. Accidental spills and leakage from underground storage tanks results in the formation of PHC source zones that release hundreds of organic compounds, including the high impact, acutely toxic and highly persistent aromatics (e.g., benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) into groundwater. Contamination by these compounds continues to persist until the PHC source zone is treated in place or removed. In situ chemical oxidation (ISCO) employing persulfate was identified as a potentially viable technology for the treatment of PHC source zones. The effectiveness and efficiency and, therefore, the overall economic feasibility of a persulfate-based ISCO treatment system depend upon the reactivity of the target organic compounds and the interaction of persulfate with aquifer media. The objective of this research was to investigate the persistence of unactivated and activated persulfate in the presence of aquifer materials, and to examine persulfate oxidation of PHC compounds at both the bench- and pilot-scales. A series of bench-scale studies were performed to estimate persulfate degradation kinetic parameters in the presence of seven well-characterized, uncontaminated aquifer materials and to quantify the changes in specific properties of these materials. Batch experiments were conducted in an experimental system containing 100 g of solids and 100 mL of persulfate solution at 1 or 20 g/L. Column experiments were designed to mimic in situ conditions with respect to oxidant to solids mass ratio and were performed in a stop-flow mode using a 1 g/L persulfate solution. The degradation of persulfate followed a first-order rate law for all aquifer materials investigated. An order of magnitude decrease in reaction rate coefficients was observed for systems that used a persulfate concentration of 20 g/L as compared to those that used 1 g/L due to ionic strength effects. As expected, the column experiments yielded higher reaction rate coefficients than batch experiments for the same persulfate concentration due to the lower oxidant to solids mass ratio. Bench-scale data was used to develop a kinetic model to estimate the kinetic response of persulfate degradation during these tests. The push-pull tests involved the injection of persulfate (1 or 20 g/L) and a conservative tracer into a hydraulically isolated portion of the sandy aquifer at CFB Borden, Canada. The kinetic model developed from the bench-scale data was able to reproduce the observed persulfate temporal profiles from these push-pull tests. This implies that persulfate degradation kinetics is scalable from bench-scale to in situ scale, and bench tests can be employed to anticipate in situ degradation. The estimated reaction rate coefficients indicate that persulfate is a persistent oxidant for the range of aquifer materials explored with half lives ranging from 2 to 600 days, and therefore in situ longevity of persulfate will permit advective and diffusive transport in the subsurface. This is critical for successful delivery of oxidant to dispersed residuals in the subsurface. Activation of persulfate is generally recommended to enhance its oxidation potential and reactivity towards organic compounds. This approach may influence the stability of persulfate-activator system in the presence of aquifer materials. A series of batch tests were performed to investigate persistence of persulfate at two concentrations (1 or 20 g/L) using three contemporary activation strategies (citric acid chelated-ferrous, peroxide and high pH ) in the presence of 4 well-characterized, uncontaminated aquifer materials. Chelation by citric acid was ineffective in controlling the interaction between persulfate and Fe(II) and a rapid loss in persulfate concentration was observed. Higher Fe(II) concentration (600 mg/L) led to greater destabilization of persulfate than lower Fe(II) concentration (150 mg/L) and the persulfate loss was stoichiometrically equivalent to the Fe(II) concentration employed. Subsequent to this rapid loss of persulfate, first-order degradation rate coefficients (kobs) were estimated which were up to 4 times higher than the unactivated case due to the interaction with Fe(III) and CA. Total oxidation strength (TOS) was measured for peroxide activation experiments and was observed to decrease rapidly at early time due peroxide degradation. This was followed by slow degradation kinetics similar to that of unactivated persulfate implying that the initial TOS degradation was peroxide dominated and the long-term kinetics were dominated by persulfate degradation. The kobs used to capture TOS degradation for later time were shown to depend upon unactivated persulfate and peroxide degradation rate coefficients, and peroxide concentration. Either a slow peroxide degradation rate and/or higher peroxide concentration allow a longer time for peroxide and persulfate to interact which led to kobs ~1 to 100 times higher than kobs for unactivated persulfate. For alkaline activation, kobs were only 1 to 4 times higher than unactivated persulfate and therefore alkaline conditions demonstrated the least impact on persulfate degradation among the various activation strategies used. For all activation trials, lower stability of persulfate was observed at 1 g/L as compared to 20 g/L due to insufficient persulfate and/or ionic strength effects. A series of batch reactor trials were designed to observe the behavior of the nine high impact gasoline compounds and the bulk PHC fraction measures subjected to various persulfate activation strategies over a 28-day period. This bench-scale treatability used unactivated persulfate (1 or 20 g/L) and activated persulfate (20 g/L). Activation employed chelated-Fe(II), peroxide, high pH or two aquifer materials as activators. No significant oxidation of the monitored compounds was observed for unactivated persulfate at 1 g/L, but 20 g/L persulfate concentration resulted in their near-complete oxidation. Oxidation rates were enhanced by 2 to 18 times by activation with peroxide or chelated-Fe(II). For alkaline activation, pH 11 trials demonstrated ~2 times higher oxidation rates than the unactivated results. For pH 13 activation the oxidation rates of benzene, toluene and ethylbenzene were reduced by 50% while for the remaining monitored compounds they were enhanced by 5 to 100%. Natural activation by both aquifer materials produced oxidation rates similar to the unactivated results, implying that either activation by minerals associated with aquifer material was not significant or that any potential activation was offset by radical scavenging from aquifer material constituents. Acid-catalyzation at pH <3 may enhance oxidation rates in weakly buffered systems. Oxidation of the monitored compounds followed first-order reaction kinetics and rate coefficients were estimated for all the trials. Overall, activated and unactivated persulfate appear to be suitable for in situ treatment of gasoline. Persulfate under unactivated or naturally activated conditions demonstrated significant destruction of gasoline compounds and showed higher persulfate persistence when in contact with aquifer solids as compared to chelated-Fe(II) or peroxide-activated persulfate systems. This observation was used as the basis for selecting unactivated sodium persulfate for a pilot-scale treatment of gasoline-contaminated source zone at CFB Borden, Canada where a ~2000 L solution of persulfate (20 g/L) was injected into a PHC source zone. Concentration of organics and inorganics were frequently monitored over a 4 month period across a 90 point monitoring fence line installed down-gradient. Treatment performance was measured by estimating organic and inorganic mass loading across the monitoring fence. Increased mass loading for sodium was observed over time as the treatment volume moved across the fence-line indicating transport of the inorganic slug created upon oxidant injection. The mass loading also increased for sulfate which is a by-product generated either due to persulfate degradation during oxidation of organic compounds or during its interaction with aquifer materials. Oxidation of organic compounds was evident from the enhanced mass loading of dissolved carbon dioxide. More importantly, a significant (45 to 86%) decrease in mass loading of monitored compounds was observed due to oxidation by injected persulfate. The cumulative mass crossing the monitoring fence-line was 20 to 50% lower than that expected without persulfate treatment. As the inorganic slug was flushed through the source zone and beyond the monitoring fence, the mass loading rate of sodium, sulfate and carbon dioxide decreased and approached background condition. Mass loading of the monitored compounds increased to within 40 to 80% of the pre-treatment conditions, suggesting partial rebound. These investigations assessed the impact of activation on persulfate persistence and treatability of gasoline and served to establish guidelines for anticipating field-scale persulfate behavior under similar conditions. In summary, unactivated persulfate is a stable oxidant in the presence of aquifer materials and its persistence depends upon TOC and Fe(Am) content of the materials, ionic strength, and aquifer to solids mass ratio. Persulfate exhibits significant destruction of gasoline compounds and can be employed for the remediation of gasoline-contaminated sites. Peroxide and chelated-Fe(II) enhance oxidation rates of these compounds, but reduce stability of the persulfate-activator system. Persulfate activation using high pH conditions does not significantly impact persulfate persistence but reduces the overall destruction of gasoline compounds. Therefore, activation imposes a trade-off between enhanced oxidation rates and reduced persulfate persistence. Kinetic model is representative of persulfate degradation at bench- and pilot-scales and can be used for estimation of in situ degradation. The quantification of oxidation rates for gasoline compounds under activated and unactivated persulfate conditions will assist decision-making for identification of appropriate remediation options when targeting contamination by gasoline or by specific high impact gasoline compounds. While persulfate oxidation resulted in partial treatment of a small gasoline source zone, aggressive persulfate load will be required during injection for a complete clean-up. Overall, persulfate-based in situ chemical oxidation was demonstrated to be an effective and a viable technology for the remediation of contaminated soil and groundwater.

ABSTRACT THE EFFECT OF PRE-TRANSFER GRADE POINT AVERAGE ON POST-TRANSFER GRADE POINT AVERAGE AS AN INDICATOR OF PERSISTENCE FROM TWO-YEAR COLLEGES TO STATE COLLEGES AND UNIVERSITIES WITHIN THE UNIVERSITY SYSTEM OF GEORGIA by Marci M. Middleton Community colleges provide an important access point for students who want to continue their educational studies and obtain a baccalaureate or advanced degree. Students have the opportunity to complete core curricula or the general education component of their education at a two-year college and then transfer to a four-year college or university in many higher education systems around the country including the University System of Georgia. Using linear regression initially and later multiple regression, this quantitative research study tested grade point average to project student academic performance at a state or research university upon transfer to such institutions. Data obtained for state systems institutions from fall 2001 through fall 2005 was used for the administration of this study. Research questions concerning the relationship between grade point averages before and after transfer were examined at various matriculation points with specific attention paid to pre-transfer grade point average and post-transfer grade assessment at three points across a student’s academic career. In addition, the strength of the relationship was tested for the aggregate student cohort of matriculants from fall 2001 through fall 2005 as well as sub-groups within the cohort.

Background: Coinfections with multiple types of human papillomavirus (HPV) are a common occurrence among HPV-infected individuals, but the clinical significance and etiology of these infections remain unclear. Though current evidence suggests that women with coinfections have increased HPV exposure (i.e. more sexual partners), it is also hypothesized that these women may represent a subgroup with increased HPV susceptibility, though this has been rarely studied to date. Purpose: The purpose of this project was to examine the occurrence, determinants and dynamics of HPV coinfections in a cohort of university students in order to explore the relationship(s) between coinfections, lifestyle factors and immunological susceptibility. Methods: This project is based on a secondary analysis of data from the McGill-Concordia Cohort, a longitudinal study of the natural history of HPV infection in 621 female university students in Montreal, Quebec. Participants were followed for 2 years at 6-month intervals. At each visit, cervical specimens were collected for cytology and HPV testing, and women completed a questionnaire about lifestyle and risk behaviours. Two definitions of coinfections were used: cumulative coinfection over follow-up and concurrent coinfection at each visit. Kaplan-Meier techniques were used to estimate incidence and duration of coinfections and multiple logistic regression was used to identify determinants of coinfections and associations between coinfections and squamous intraepithelial lesions (SIL). Results: More than half of the cohort became infected with HPV and of those, over 60% acquired multiple HPV types over follow-up. Incidence of coinfections was significantly increased among HPV-infected women at enrollment. The most important determinant of coinfection occurrence was number of sexual partners (both lifetime and new), though some genes of the immune response (HLA-DQB1*06:02, HLA-G*01:01:03 and HLA-G*01:01:05) were also significant predictors. Women with coinfections, particularly those with 4+ HPV types, also had longer infection durations and greatly increased odds of SIL. Conclusions: Women with coinfections acquire new HPV types at an increased rate and have greater HPV persistence and occurrence of SIL, which may indicate immunological susceptibility. HPV coinfections mainly occur due to increased sexual activity but a decreased immune response to the virus may also be involved in a subset of women. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2011-04-21 01:04:26.265

An under representation of Latino/as in the fields of science, technology, engineering and math (STEM) still persists. In Rising Above the Gathering Storm , the National Academies sounded an alarm in response to data indicating a "troubling decline" in the number of U.S. citizens trained to become scientists and engineers at a time when the number of technical jobs is outpacing the rate of the U.S. workforce. The shrinking technical talent pipeline threatens the country's future in technology innovation, energy alternatives, national security, and education. This study purported to contextualize resilience and discern the cultural capital and persistence behaviors of STEM Latino/a students succeeding in two adverse environments--higher education and science and engineering. Through a critical race perspective the student cuentos were thematically analyzed. Student narratives were then triangulated with the narrative of the researcher--a Mexican American, first-generation college student, who pursued a life science bachelor's degree through the two institutions in this study. The theoretical framework was guided by Critical Race Theory, Resiliency, Persistence Theory, and Social Construction of Technology. The study consisted of a pilot survey and narrative inquiry. The survey contained pilot questions on the use and perception of information technologies in STEM education. The narrative inquiry was guided by critical race that enabled both positionality and storytelling through narratives and counter-narratives. Twenty-two Latino/a graduating seniors majoring in the biological sciences or engineering/engineering technology at a Hispanic-Serving Institution (HSI) and a Predominantly-White Institution (PWI) in Texas were recruited. The narratives of these students were collected through one-time, semi-structured interviews during the last semester of their studies. Results from the study indicate that these Latino/a STEM students are conscious of their ethnicity; however, they are not critically conscious of the master narrative of what it means to be a Latino/a in a STEM discipline. These students have bought into the master narrative of colorblind science and engineering. The students understood that to succeed in STEM, they had to survive based on their proficiency with institutional norms, practices and cultures and then maintain a sense of self through a respect for their Latino culture.

Chlamydia, caused by the bacterium Chlamydia trachomatis, is one of the most important sexually-transmitted infections globally. In addition to accounting for millions of cases every year, the disease causes numerous irreversible complications such as chronic pelvic pain, infertility in females and pelvic inflammatory disease. This thesis presents a number of mathematical models, of the form of deterministic systems of non-linear differential equations, for gaining qualitative insight into the transmission dynamics and control of Chlamydia within an infected host (in vivo) and in a population. The models designed address numerous important issues relating to the transmission dynamics of Chlamydia trachomatis, such as the roles of immune response, sex structure, time delay (in modelling the latency period) and risk structure (i.e., risk of acquiring or transmitting infection). The in-host model is shown to have a globally-asymptotically stable Chlamydia-free equilibrium whenever a certain biological threshold is less than unity. It has a unique Chlamydia-present equilibrium when the threshold exceeds unity. Unlike the in-host model, the two-group (males and females) population-level model undergoes a backward bifurcation, where a stable disease-free equilibrium co-exists with one or more stable endemic equilibria when the associated reproduction number is less than unity. This phenomenon, which is shown to be caused by the re-infection of recovered individuals, makes the effort to eliminate the disease from the population more difficult. Extending the two-group model to incorporate risk structure shows that the backward bifurcation phenomenon persists even when recovered individuals do not acquire re-infection. In other words, it is shown that stratifying the sexually-active population in terms of risk of acquiring or transmitting infection guarantees the presence of backward bifurcation in the transmission dynamics of Chlamydia in a population. Finally, it is shown (via numerical simulations) that a future Chlamydia vaccine that boosts cell-mediated immune response will be more effective in curtailing Chlamydia burden in vivo than a vaccine that enhances humoral immune response. The population-level impact of various targeted treatment strategies, in controlling the spread of Chlamydia in a population, are compared. In particular, it is shown that the use of treatment could have positive or negative population-level impact (depending on the sign of a certain epidemiological threshold).

To understand the temporal dynamics of a forest, long-term direct observations are required. My study examined the long-term persistence of trembling aspen (Populus tremuloides Michx) and white spruce (Picea glauca (Moench) Voss) in the boreal mixed-wood forests of Riding Mountain National Park. A set of 266, disturbance-free, permanent sample plots were established in 1947 (stand age = 120 years) and followed through time for 55 years. My results indicate that although the density and basal areas of aspen do decline over the 55-year period, a successful regeneration and establishment occurs around 140 years. The long-term persistence of aspen is a result of clonal reproduction following the canopy breakup beginning around 130 years or earlier. This implies that the long-term persistence of both aspen and spruce occur and the expected succession to softwood dominance does not occur.

Spiny amaranth is a problematic weed of heavily grazed pastures in Kentucky and surrounding states. The first objective was to evaluate spiny amaranth control when herbicides are applied before and after emergence. Spiny amaranth seed collected in 2008 were seeded in rows in the fall (November) and the following spring (March) in fields located near Lexington and Princeton, KY. Treatments consisted of five application dates and five herbicides plus an untreated control arranged in a split-split plot design. The following parameters were measured: fresh weight, plant height and percent visual control. At both locations pendimethalin applied in November, March and April before spiny amaranth emergence gave the greatest control and significantly reduced fresh weight biomass compared to other treatments. June applications of 2,4-D reduced plant height and provided 80 control. Fresh weight biomass and height were also reduced with dicamba, aminopyralid and aminocyclopyrachlor applied in June compared to pendimethalin and the untreated control. A soybean bioassay was conducted to measure soil dissipation of aminopyralid, a common pasture herbicide active ingredient. Soil samples were collected from two sites in Lexington and Princeton. During a season of above average rainfall aminopyralid had dissipated from the soil within 16 weeks at Lexington and by 4 weeks at Princeton.

This Study examined issues related to persistence in higher education among African American students, using the prominent model proposed by Vincent Tinto. The intentions were to examine the growing gender gap among African American students. The study examines factors from the Tinto model such as high school GPA, College GPA, college social integration and academic integration to try and explain the effects of gender among African American students. This research also attempts to elaborate the Tinto model by considering high school extracurricular activities as a pre-entry attribute that has an effect on persistence in higher education. Use of the Tinto model, even in an elaborated state, did not explain the effects of gender among African American students. This research suggests that other factors not included in the model have some effect on student persistence; one such factor could be gender socialization which can lead to different patterns in educational achievement.

This study seeks to explore the relationship between intercultural communication experiences and college persistence in first-generation college students from the Central Appalachian region. Because Appalachia has a rich and unique culture, which is often misunderstood, the literature review seeks to establish a basis for studying this relationship as a way to understand the multi-dimensional nature of low-educational attainment in the Appalachian region, particularly Eastern Kentucky, Tennessee, Virginia, and West Virginia. Using a survey-based quantitative method this study examines Appalachian first generation students attending college as an intercultural communication process through the frame of acculturation theory. Specifically, the study seeks information about the students’ previous intercultural communication experiences, cultural identity, intercultural sensitivity, and college persistence. This study attempts to predict first generation, Appalachian students’ college persistence with their previous intercultural communication experiences, cultural identity, and intercultural sensitivity.