Effects of Teacher-mediated Repeated Viewings of Stories in American Sign Language on Classifier Production of Students who are Deaf or Hard of Hearing

Students who are deaf and use sign language frequently have language delays that affect their literacy skills. Students who use American Sign Language (ASL) often lack fluent language models in both the home and school settings, delaying both the development of a first language and the development of literacy in printed English. Mediated and scaffolded instruction presented by a More Knowledgeable Other (MKO; Vygotsky, 1978, 1994) may facilitate acquisition of a first foundational language. Repeated viewings of fluent ASL models on DVDs paired with adult mediation has resulted in increases in vocabulary skills for DHH students who used ASL (Cannon, Fredrick, & Easterbrooks, 2010; Golos, 2010; Mueller & Hurtig, 2010). Classifiers are a syntactic sub-category of ASL vocabulary that provides a critical link between ASL and the meaning of English phrases. The purpose of this study was to investigate the effects of teacher-mediated repeated viewings of ASL stories on DHH students’ classifier production during narrative retells. This study included 10 student participants in second, third, and fourth grades and three teacher participants from an urban day school for students who are DHH. The researcher used a multiple baseline across participants design followed by visual analysis and calculation of the percentage of non-overlapping data (PND; Scruggs, Mastropieri, & Casto, 1987) to examine the effects of the intervention. All students increased their classifier production during narrative retells following a combination of teacher mediation paired with repeated viewings of ASL models

University American Sign Language (ASL) Second Language Learners: Receptive and Expressive ASL Performance

American Sign Language (ASL) is used by estimates of up to 500,000 people (deaf and hearing) in the United States (Mitchell et al., 2006); however, the majority of users are typically hearing university students, frequently within university interpreting or deaf education preparation programs, who learn ASL as a second language (L2). It is unclear how these learners develop their skills as they progress through university training programs. The present study documents university learners’ receptive and expressive ASL skills, factors related to performance, and self-evaluation and strategy use at the end of their ASL IV course. Both assessments are readily available, efficient to administer and score, and provide immediate feedback to learners. Self-reported years of ASL experience, hours of academic ASL use, fluency, and university major related to scores on an expressive handshape phonological fluency task as measured by correlations and ANOVAs. Based on student performance, implications for university instructors of L2 ASL learners are discussed

The neural correlates of speech motor sequence learning

Speech is perhaps the most sophisticated example of a species-wide movement capability in the animal kingdom, requiring split-second sequencing of approximately 100 muscles in the respiratory, laryngeal, and oral movement systems. Despite the unique role speech plays in human interaction and the debilitating impact of its disruption, little is known about the neural mechanisms underlying speech motor learning. Here, we studied the behavioral and neural correlates of learning new speech motor sequences. Participants repeatedly produced novel, meaningless syllables comprising illegal consonant clusters (e.g., GVAZF) over 2 days of practice. Following practice, participants produced the sequences with fewer errors and shorter durations, indicative of motor learning. Using fMRI, we compared brain activity during production of the learned illegal sequences and novel illegal sequences. Greater activity was noted during production of novel sequences in brain regions linked to non-speech motor sequence learning, including the BG and pre-SMA. Activity during novel sequence production was also greater in brain regions associated with learning and maintaining speech motor programs, including lateral premotor cortex, frontal operculum, and posterior superior temporal cortex. Measures of learning success correlated positively with activity in left frontal operculum and white matter integrity under left posterior superior temporal sulcus. These findings indicate speech motor sequence learning relies not only on brain areas involved generally in motor sequencing learning but also those associated with feedback-based speech motor learning. Furthermore, learning success is modulated by the integrity of structural connectivity between these motor and sensory brain regions.R01 DC007683 - NIDCD NIH HHS; R01DC007683 - NIDCD NIH HH

MEASURING RATE CONSTANTS FOR THE REACTION OF HYPOCHLOROUS ACID AND BIOLOGICALLY RELEVANT MOLECULES

Hypochlorous acid (HOCl) is a neutrophil-derived oxidant that is used to kill invading pathogens. Since HOCl reacts indiscriminately with biological molecules, such as amino acids, excess or misplaced production of HOCl can cause host tissue damage. Methionine (Met), one of only two naturally occurring sulfur amino acids, reacts fast with HOCl making it one of the first targets. The mechanism for this reaction is not well known but is assumed to go through a chlorosulfonium intermediate to form methionine sulfoxide (MetO), and then methionine sulfone (MetO2).The first chapter of this dissertation introduces topics which will help the reader understand the significance of the research that is described herein. The second chapter presents the new method, which we called inhibitory titrations (IT). IT is an expansion of the competition method that is commonly used for measuring rate constants of fast reactions. IT tries to minimize assumptions that can create problems when indirectly measuring rate constants by: 1) making use of all the data collected (the rate constant measured using just the 50% inhibition point can underestimate the rate constant compared to that which fits all of the data); and 2) consideration of the stoichiometry of the reaction, which was important for accurately fitting data, especially when over-oxidation is possible. Our data shows that taking the stoichiometry of the reaction into consideration produces a better fit of the experimental data than assuming the reaction has a 1:1 stoichiometry. Without consideration of the rate law for the reaction, one may derive a first order rate constant from a second order reaction, leading to a misrepresentative rate constant.The third chapter examines thioether reactions with HOCl with the expectation that a chlorosulfonium intermediate could be characterized. In general, HOCl reacts with thioethers, at neutral pH, with a second order rate constant of 106-108 M-1s-1, consistent with those reported in literature. The reactions studied did not show definitive evidence for the formation of a chlorosulfonium ion intermediate. However, the observed product, dehydromethionine (DHM), formed in the reaction of Met with HOCl (studied in greater detail in the fourth chapter), gives insight into the identity of the intermediate. Due to the hypothesized method by which DHM is formed, from intramolecular attack followed by ring closure, a halosulfonium intermediate can account for the formation of the DHM product.The fourth chapter describes an investigation of the reaction of free Met, peptide bound Met, and protein bound Met, by various two electron oxidants. Oxidation of Met, which has a free amine, can form either MetO or DHM, a potential biomarker of oxidative stress. Different oxidants form different percentages of DHM. Two electron oxidants that react through oxygen transfer do not produce DHM, while halogenating species (but not the pseudohypohalous acid HOSCN) that react through a halide cation (X+, where X = I, Br, or Cl) transfer, produce a significant amount of DHM. The halogenating agents can be grouped by the yields of DHM they produce, where chlorinating agents produce around 43% DHM, brominating agents approximately 75%, and iodinating agents close to 100% DHM. The percentage of DHM formed is related to the type of halosulfonium that is formed, whether it is a chlorosulfonium, bromosulfonium, or iodosulfonium species. Comparing analogous halosulfonium species, the stability towards hydrolysis is I > Br > Cl, reflecting the trend observed in the yields of DHM. The ease of formation along with the high kinetic stability of DHM at neutral pH, which in the absence of catalysts has a half life of over 600 days, shows the high potential for DHM as a biomarker of protein oxidation by halogenating agents.The fifth chapter is a summary of important findings of this research along with recommended future experiments. Overall, the dissertation examines fast (k = 106-108 M-1s-1) reactions of HOCl and related oxidants with biologically relevant molecules

Goodnight Gorilla: How Do Second Language Learners’ American Sign Language Narrative Renditions Change after Viewing an ASL Model?

We investigated the effects of a single viewing of an American Sign Language (ASL) model on university second language learners’ ASL narrative renditions. Spoken English was the first language of all participants and they had varied lengths of signing experience, ranging from 1 to 26 years. Participants completed a receptive measure of ASL. Then they rendered a wordless picture book in ASL. Afterwards, they watched a native-signing adult model of the story in ASL, and then told the story again. We investigated their inclusion of specific details and how they expressed them, including their use of constructed action (CA), depicting constructions (DCs), blended CA+DC, and lexical signs. After one viewing of the model, participants significantly increased their inclusion of details and use of all constructs except lexical signs, although not to the level of the model. Their receptive ASL scores correlated with their use of CA within their narrative renditions at both time points. We present an analysis of their strengths and areas of need, as well as future research implications

Population dynamics in cloned CHO cell lines

The inherent nature of cloned CHO cell lines includes the presence of genetic and phenotypic drift that leads to heterogeneous populations. The genetic heterogeneity exhibited by these cells can be exploited to understand the population dynamics of cloned cell lines. One way to track heterogeneity within populations is by utilizing genetic sequence variants (SVs) as biomarkers for distinct populations. In the experiments described here, cell lines with varying levels of sequence variants resulting from a single nucleotide change in the gene of interest were used to study population dynamics in cloned CHO cell lines. Analysis of four different monoclonal antibody-expressing cell lines with known sequence variants under varying continuous culture conditions provided insight into transcription and translation rates of SV-containing cell lines and allowed us to generate population dynamic models leading to better understanding of SVs and the genetic heterogeneity of clonal cell lines. Early time points of these cell lines were further subcloned and analyzed to gain further understanding of subpopulation dynamics in cloned cell lines and the results of these experiments will be presented. Subclones of these four clonal cell lines proved varying degrees of heterogeneity while falling into distinct population dynamics models. Additionally, mixing of subclones expressing the same mAb, with and without SVs at similar growth rates allowed us to evaluate how populations shift over time. A range of expected and unexpected outcomes was observed with these intentionally mixed populations demonstrating the complexity of clonal cell line heterogeneity. This study will further our understanding on the interplay between clonality, heterogeneity and population dynamics of “clonal” cell lines and will allow for critical assessment of overarching cell line development methods and strategies

The Role of Emotional Reactivity, Self-regulation, and Puberty in Adolescents\u27 Prosocial Behaviors

This study was designed to examine the roles of emotional reactivity, self-regulation, and pubertal timing in prosocial behaviors during adolescence. Participants were 850 sixth graders (50% female, Mean age = 11.03, SD = .17) who were followed up at age 15. In hierarchical regression models, measures of emotional reactivity, self-regulation, pubertal timing and their interactions were used to predict (concurrently and over time) adolescents’ prosocial behaviors in the home and with peers. Overall, the findings provide evidence for pubertal and temperament based predictors of prosocial behaviors expressed in different contexts. Self-regulation was positively related to both forms of prosocial behavior, concurrently and longitudinally. Emotional reactivity showed moderately consistent effects, showing negative concurrent relations to prosocial behavior with peers and negative longitudinal relations (four years later) to prosocial behavior at home. Some curvilinear effects of temperament on prosocial behaviors were also found. Effects of pubertal timing were found to interact with gender, such that boys who were early maturers showed the highest levels of prosocial behavior at home concurrently. Discussion focuses on the role of temperament-based mechanisms in the expression of prosocial behaviors in different contexts in adolescence

HIV Testing Policies in Florida

To combat the HIV/AIDS epidemic, strong policies that promote HIV testing are a primary mechanism for helping public health officials to understand the populations at risk, informing prevention initiatives, and linking infected individuals to the timely care they need. This paper describes HIV testing policies with the goal of improving early diagnosis and treatment of Floridians

University American Sign Language Learners: Longitudinal Self- and Faculty Evaluation Ratings

Students who are Deaf or hard of hearing (D/HH) represent a small yet diverse population of students with individual needs who often receive educational services provided by sign language interpreters and teachers of the Deaf/hard of hearing (D/HH). Many interpreters and teachers appear unprepared to model fluent American Sign Language (ASL) skills when working with D/HH students who use sign language for communication and instruction. We investigated the ASL skills of 19 interpreting and Deaf education candidates within one university preparation program at two points in time: the end of ASL I class (Time 1) and a year later at the end of ASL IV (Time 2). We used video recordings of candidates’ signed renditions of a picture book, a rubric of 12 sign language indicators with five levels of proficiency across each indicator, and ratings conducted independently by the candidates and the five authors. Four of these authors were university professors in two different Deaf education/interpreting preparation programs and the fifth was a teacher at a residential school for the Deaf. Three have typical hearing and use ASL as a secondary language; two are Deaf and use ASL as their primary language. We compared candidates’ self-ratings to those of the five authors. We found that candidates tended to over-estimate their skills at T1; self-ratings and author ratings increased from T1 to T2, and candidates had higher agreement with most authors at T2 compared to T1. In addition, we found differences among ratings between the university faculty and the high school teacher. We discuss these differences in our findings and address implications for evaluating and improving university candidates’ ASL skills

Planum temporale asymmetry in people who stutter

Previous studies have reported that the planum temporale - a language-related structure that normally shows a leftward asymmetry - had reduced asymmetry in people who stutter (PWS) and reversed asymmetry in those with severe stuttering. These findings are consistent with the theory that altered language lateralization may be a cause or consequence of stuttering. Here, we re-examined these findings in a larger sample of PWS. We evaluated planum temporale asymmetry in structural MRI scans obtained from 67 PWS and 63 age-matched controls using: 1) manual measurements of the surface area; 2) voxel-based morphometry to automatically calculate grey matter density. We examined the influences of gender, age, and stuttering severity on planum temporale asymmetry. The size of the planum temporale and its asymmetry were not different in PWS compared with Controls using either the manual or the automated method. Both groups showed a significant leftwards asymmetry on average (about one-third of PWS and Controls showed rightward asymmetry). Importantly, and contrary to previous reports, the degree of asymmetry was not related to stuttering severity. In the manual measurements, women who stutter had a tendency towards rightwards asymmetry but men who stutter showed the same degree of leftwards asymmetry as male Controls. In the automated measurements, Controls showed a significant increase in leftwards asymmetry with age but this relationship was not observed in PWS. We conclude that reduced planum temporale asymmetry is not a prominent feature of the brain in PWS and that the asymmetry is unrelated to stuttering severity. [Abstract copyright: Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.