The goal of this dissertation is to argue on the basis of the minimalist framework that the topichood of sentence topics and contrastive focus result from derivational and structural differences in the left periphery and to provide acquisition data from child language to support this claim, showing data from Korean, a free word-order and pro-drop language in which topics and contrastive foci are realized morphologically. In Korean, topic phrases merge in the left periphery and contrastive focus phrases undergo scrambling, one of the shared properties of free word-order languages. It is consistent in fixed word-order languages such as Italian and Hungarian and a free word-order language like Korean that topics merge and contrastive foci move to the left. Topics precede contrastive foci: topics merge in TopP, a higher functional projection than FocP, to which focus phrases move. In the process of language acquisition, the derivational and structural differences between topic phrases and contrastive focus phrases may have influences on the developmental order of grammar acquisition. In acquisition data from two-year-old Korean children, topics emerge earlier than contrastive foci, indicating that topic and contrastive focus are also acquisitionally different. This study is the first attempt to examine the structural differences and the influence on language acquisition of morphologically derived topic phrases and contrastive focus phrases in acquisition data from a free word-order and pro-drop language. This study shows the structural consistency of topic and contrastive focus between a free word-order language and fixed word-order languages. The syntactic and acquisitional distinction of topic merge and contrastive focus movement is compatible with the semantic and pragmatic approaches to topic and focus. This study provides evidence of the syntactic differences between topic and contrastive focus without dependence on phonetic features; therefore, this study is a base for drawing a map of the left periphery of human languages. / text

published_or_final_version / Linguistics / Master / Master of Arts in Applied Linguistics

published_or_final_version / abstract / toc / Educational Psychology / Master / Master of Social Sciences

published_or_final_version / abstract / toc / Educational Psychology / Master / Master of Social Sciences

Bacterial organisms continuously maintain homeostasis even in changing environments. This ability to maintain homeostasis is especially critical for pathogenic and opportunistic bacteria, which must adapt to both abiotic and biotic host environments. Both types of environments present unique limitations and conditions. Transition metal homeostasis under these varying conditions is important for bacterial survival. Transition metals such as zinc, cobalt, iron and copper are essential for cell survival, but become toxic if in excess. The host organism often takes advantage of this requirement by greatly limiting access to transition metals to limit infections, but in other environments, toxic levels of metal may be present. Bacterial organisms have developed many mechanisms to maintain transition metal homeostasis. This study focuses on two bacterial systems that are utilized to maintain metal balance; the heme-acquiring iron surface determinant (Isd) system of Bacillus anthracis and the copper and silver export Cus system of Escherichia coli. Host organisms use many proteins and systems to limit iron access from pathogenic bacteria, known as nutrient immunity. B. anthracis must acquire iron from the host organism upon infection and so has evolved multiple iron acquisition systems. The Isd system employs two extracellular proteins, IsdX1 and IsdX2, to remove heme from hemoglobin to use as an iron source. Once bound to heme, these hemophores transfer heme to a cell surface attached protein, IsdC, which further relays the molecule to be transferred into the cell for iron use. This study focused on the kinetics of heme transfer to better understand how acquisition occurs. This study determined that the oxidation state of the iron-heme molecule plays a significant role in the kinetics of heme acquisition by IsdX1 and subsequent transfer to IsdC. This work clarifies and further establishes the mechanism of iron acquisition by B. anthracis during infection. Copper and silver are used in many settings as antimicrobial agents, including as an alternative to antibiotic drugs. Pathogenic and opportunistic bacteria, such as E. coli, experience stress upon contact with copper and silver surfaces and materials. Copper is an essential transition metal, while silver is not biologically used, but both become toxic when in excess due to redox properties and disruption of biological molecules. E. coli utilizes several systems to remove excess copper and silver to resist toxicity. The Cus system, consisting of the soluble CusF and tripartite pump CusCBA, specifically exports copper and silver from the periplasm. Several roles of CusF have been suggested from in vitro data. The components CusAB were hypothesized to be the essential proteins of the CusCBA pump, while the outer membrane unit may not contribute specificity or be necessary for export. This study focused on the role and importance of CusF and outer membrane channel CusC during copper stress in vivo. An in vivo interaction between CusF and CusB was identified during copper stress. The data from this work indicate that cusF and cusC directly affect intracellular copper accumulation. Furthermore, this study revealed that SdsP may play in a secondary role to CusC to complement CusC to maintain copper resistance. This works establishes the importance of CusC as the main outer membrane component during copper export in E. coli.

Designers of automatic target recognition algorithms (ATRs) need to compare the performance of different ATRs on a wide variety of imagery. The task would be greatly facilitated by an image complexity metric that correlates with the performance of a large number of ATRs. The ideal metric is independent of any specific ATR and does not require advance knowledge of true targets in the image. No currently used metric meets both these criteria. Complete independence of ATRs and prior target information is neither possible nor desirable since the metric must correlate with ATR performance. An image complexity metric that derives from the common characteristics of a large set of ATRs and the attributes of typical targets may be sufficiently general for ATR comparison. Many real-time, tactical ATRs operate on forward looking infrared (FLIR) imagery and identify, as potential targets, image regions of a specific size that are highly discernible by virtue of their contrast and edge strength. For such ATRs, an image complexity metric could be based on measurements of the mutual discernibility of image regions on various scales. This paper: (1) reviews ATR algorithms in the public domain literature and investigates the common characteristics of both the algorithms and the imagery on which they operate; (2) shows that complexity measurement requires a complete segmentation of the image based on these commonalities; (3) presents a new method of scale-specific image segmentation that uses the mask-driven close-open transform, a novel implementation of a morphological operator; (4) reviews edge detection for discernibility measurement; (5) surveys image complexity metrics in the current literature and discusses their limitations; (6) proposes a new local feature discernibility metric based on relative contrast and edge strength; (7) derives a new global image complexity metric based on the probability distribution of local metrics; (8) compares the metric to the output of a specific ATR; and (9) makes suggestions for further work.

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No description available.

Recent studies in the acquisition of a second language (L2) phonology have revealed that orthography can influence, both positively and negatively, the way L2 learners come to establish target-like lexical representations. The majority of these studies, however, involve language pairs relying on a Roman-based script. In comparison, the influence of a foreign or unfamiliar written representation on L2 phonolexical acquisition remains understudied. This dissertation aims to fill this gap. CHAPTER 2 considers the effects of multiple scripts (e.g. Arabic, Cyrillic, Roman-Maltese, etc.) on the acquisition of the Arabic voiceless pharyngeal fricative /ħ/ and the voiceless uvular fricative /χ/ word-initially. Monolingual native speakers of English participated in a set of five word-learning experiments where they were instructed to learn six pairs of minimally contrastive words, each associated with a unique visual referent. In each experiment, a different script configuration was manipulated. After an initial learning phase, participants were then tested on their phonological acquisition of these L2 minimal pairs. Results show significant differences in phonological accuracy between groups of learners exposed to varying degrees of script unfamiliarity. Specifically, complete script foreignness exerted an inhibitory effect on L2 phonolexical acquisition, while semi-foreign scripts exercised differential inhibitory effects based on whether grapheme-phoneme correspondences (GPCs) also activated L1 phonological units. Two follow-up spelling experiments were also conducted in an attempt to find a more intuitive, symbolic representation of these L2 phonemes. While spellers managed to find various ways to symbolically encode /χ/-words from /ħ/-words, when presented in minimal pairs (but not when presented randomly), no form-consistent pattern emerged from their spelling renditions. These spelling experiments nevertheless support the interpretation that L1 GPCs are likely activated in the course of L2 phonological processing. CHAPTER 3 examines the acquisition of another nonnative phonological contrast, that of Japanese singleton/geminate consonants word-medially. In another set of five word-learning experiments manipulating various aspects of unfamiliar scripts (e.g. Hiragana, Roman/Cyrillic blended), it was found that the acquisition of such a length-based contrast was significantly affected by the foreign written input only when the unfamiliar characters encoding the contrast were graphically highlighted (by way of font coloring and underline) or when they did not convey any information about the durational dimension of the L2 contrast (i.e. when both singletons and geminates were represented with a single character, instead of two for the geminates). These inhibitory effects show that learners are susceptible to be confused by small details featured in unfamiliar written representations presented to them in the course of L2 phonoloxical acquisition. Similar to Chapter 2, two follow-up spelling experiments were conducted. Here, spellers failed to symbolically mark a difference between singleton and geminate auditory items, whether they were presented randomly or in minimal pairs. This lack of differentiation in writing suggests that a consonantal singleton/geminate contrast is a priori not so intuitive to native English speakers. The contributions of this dissertation are manifold. First, the present results provide strong evidence that, aside from recognized acoustic and phonological features influencing the acquisition of a second language sound system, extra-linguistic elements such as written representations also contribute to the acquisitional experience of L2 learners. Furthermore, such findings show that exposure to unfamiliar written representations can significantly inhibit the successful creation of target-like phonological representations, an outcome that has thus far not been attested. Second, it provides additional and complementary research in the subfield of L2 acquisition dealing with the interaction of phonological and orthographic knowledge. The work presented here indeed expands the scope of L2 contrasts and script treatments thus far investigated. Third, implications for second language teaching and loanword phonology can be envisaged. Methods geared towards the acquisition of L2 sounds for instance could be designed taking into account the results obtained here, namely, the fact that a foreign written support may not always be beneficial to learners, depending on the degree of familiarity with the L2 writing system.

The Spanish voiced alveolar multiple vibrant consonant /r/, or trill, is often regarded as one of the most difficult sounds in the Spanish phonological inventory for second language (L2) learners. Trills are particularly difficult segments because of their exacting articulatory requirements for production. The highly restricted gestural and aerodynamic configuration required to successfully produce trills could lead to non-native trills automatically being native-like once acquired by learners, unlike other segments which generally show measurably gradient approximation of native values over time. This study employed two experiments to investigate the characteristics of L2 acquisition of Spanish /r/ by adult native speakers of English. The first experiment broadly surveyed the frequency of trill production at four levels of proficiency and among a comparison group of native speakers of Mexican Spanish when trills were the target segments in words. This experiment was designed to show the rate of trill frequency at different learner-levels and to compare it with the rate at which native speakers produce trills. A pattern of increasing ability to produce trills as proficiency level increased was found, as was a pattern of substitution of the alveolar tap as an intermediate strategy among learners who had ceased to transfer American English <italic>r</italic> but who had not yet acquired the ability to produce trills consistently. The second experiment investigated the aerodynamic properties of successfully produced trills to see if the trills of learners who had acquired the ability to produce trills displayed different physical properties from native speakers' trills. Patterns of both "categorical" and "gradient" acquisition were found. On the several measures studied, non-native trills showed patterns of acquisition in which their trills either were immediately native-like, acquired with non-native-like properties which fossilized with no further improvement, or showed gradient improvement in the direction of nativeness as proficiency level increased.