Building upon current research in native-speaker (NS) perception of L2 learner phonology (Zielinski, 2008; Derwing & Munro, 2009), the present investigation analyzed multiple dimensions of NS speech perception in order to achieve a more complete understanding of the specific linguistic elements and attitudinal variables that contribute to perceptions of accent in learner speech. In this mixed-methods study, Spanish monolinguals (n = 18) provided information regarding their views of L1 American English (AE) speakers learning Spanish and also evaluated the extemporaneous production of L2 learners from this same population. The evaluators' preconceived attitudinal notions of L1 AE speakers learning Spanish negatively correlated with numerical accentedness ratings for the speech samples, indicating that evaluators with more positive perceptions of the learners rated their speech as less accented. Following initial numerical ratings, evaluators provided detailed commentary on the individual phonological elements from each utterance that they perceived as "nonnative." Results show that differences in the relative salience of the nonnative segmental productions correspond with certain phonetic and phonemic processes occurring within the sounds, such as aspiration, spirantization and lateralization. / Spanish

Nonnative fishes are a major threat to biodiversity and new species continue to be introduced. In this dissertation, I described patterns and assessed determinants of fish invasions in the Mid-Atlantic region of the United States. Data on nonnative fish distributions were obtained from the United States Geological Survey's Nonindigenous Aquatic Species Database (NASD). Nonnative fishes are introduced by a variety of pathways, and prevention efforts can be optimized by focusing on pathways posing the greatest risk of new invasions. To assess the importance of existing pathways, I described the species associated with each pathway, analyzed the number of species introduced by decade for certain pathways, and estimated the detectability and probability of establishment of species introduced by each pathway. Additionally, I reviewed the efficacy of existing regulations for preventing introductions via each pathway. Historically, the intentional introduction of centrarchids and salmonids for sport was the dominant pathway. Pathways currently posing the greatest risks included bait release, illegal introductions, stocking of private ponds, and several pathways associated with economic activities. These pathways involved cyprinids, catostomids, and species exotic to North America. Regulations varied considerably among states, and I suggest that region-wide prohibitions on the release of nonnative species into the wild would help prevent additional introductions. Mid-Atlantic region watersheds differ considerably in nonnative species richness (NNSR), suggesting they are not equally invasible. I analyzed relationships between ecosystem characteristics and invasibility by compiling data on watershed characteristics and correlating these with NNSR. I included measures of colonization pressure (i.e., the number of species introduced) and research effort, which can bias patterns of NNSR. After controlling for these factors, the range in elevation in a watershed explained the greatest variation in NNSR. Highland watersheds had greater NNSR, probably because of greater habitat heterogeneity due in part to human activity. I suggest that NNSR can be reduced by restoration activities that reduce the diversity of artificial habitats available in highland watersheds. Ecosystems with similar NNSR may be invaded by different species, because differences in ecosystem characteristics may regulate the types of species that are able to establish. To explain differences in nonnative species among ecosystem types, I grouped Mid-Atlantic region watersheds by nonnative community and tested for differences in ecosystem characteristics among groups. Four groups were identified. A large, speciose group in the north-west portion region was characterized by smallmouth bass (Micropterus dolomieu). A large, speciose group in the south-west portion of the region was characterized by largemouth bass (Micropterus salmoides). Two smaller groups with few species were found on the coastal plain; one to the north, characterized by black crappie (Pomoxis nigromaculatus) and a second to the south characterized by white crappie (Pomoxis annularis). Nonnative community type was correctly predicted 80% of the time by models based on temperature and range in elevation. Relatively uninvaded watersheds in the south-east part of the region were predicted to host the most diverse nonnative community, suggesting that risks of invasion are high there. These results demonstrate the importance of species identity in determining ecosystem invasibility. There is no consensus on how to estimate the relative impacts of nonnative species. I developed and compared several approaches for doing so. I estimated impact by surveying fish biologists regarding the abundance and socioeconomic and ecological impacts of each species. I obtained fish collection records as an additional estimate of abundance and consulted reports of impacts in the NASD. I consulted reports of impacts in global invasive species databases as a basis for comparison. I compared top-ranked species among approaches, and game and non-game biologists' ratings of game and non-game species for each survey question. Top-ranked species differed considerably among approaches. Non-game biologists gave higher ecological impact ratings to both game and non-game species. Approaches assessing socioeconomic impacts are most appropriate for informing social decisions, such as restricting the possession or trade of a species. A combination of data from approaches assessing ecological impacts and abundance is most appropriate for studies of ecological patterns, such as testing for differences in traits between high- and low-impact species. These approaches are transferrable to other regions and taxa, and can inform management decisions and improve efforts to identify factors correlated with high-impact invaders. Collectively, my results can aid in reducing the effects of nonnative fish invasions by enabling managers to focus prevention efforts on high-impact species likely to invade particular ecosystems via known pathways. For example, bait releases, illegal introductions, private stocking, and several pathways associated with economic activities present the highest risks of future invasions, and warrant attention aimed at preventing invasions. Prevention could also be focused on several watersheds in the south-east part of the region, which currently have few established species but were predicted to be invasible by bluegill (Lepomis gibbosus), bluntnose minnow (Pimephales notatus) channel catfish (Ictalurus punctatus), and warmouth (Lepomis gulosus). This work represents major advancements in invasion biology, including new links between species identity and ecosystem invasibility and the development of methods for quantifying impact. / Ph. D.

No description available.

語用能力是語言習得成功重要的一環，但在臺灣高中的英語教學中卻未受到重視。教師的語言行為對於學生在語用和文化價值觀方面有很大的影響，所以檢視英語教師和外籍教師在語言行為是否有相似的策略有其必要性。本文著重在高中英語教師和外籍教師祈令語使用之比較，以瞭解臺灣英語教師的語言行為策略之使用和外籍教師有何異同，並進一步探討文化對語言行為之影響。 本研究利用語文完成測驗問卷(Discourse Completion Task Questionnaire)收集受試者之語料，共有50位本國籍及30位外籍高中英語教師參與研究。問卷資料主要以卡方檢定(Chi-square)，並輔以質性分析兩組受試者之回答。 研究結果指出兩組受試者均使用最多非傳統間接策略(non-conventionally indirect strategies)；但是，本國籍英語教師比外籍教師採用更多直接策略(direct strategies)，外籍教師則比本國籍教師常使用其他策略(other strategies)，例如接受學生的行為或私下約談處理。本研究證實文化的確在語言行為中扮演重要角色，更建議中外籍英語教師均有責任教導學生正確的語用知識，以協助他們在不同情境中和他人成功地溝通。

Previous studies on nonnative English speaker teachers (NNESTs) (Reyes & Medgyes, 1994; Samimy & Brutt-Griffler, 1999; Llurda, 2008; Rajagopalan, 2005) and publications in World Englishes (WEs), English as a Lingua Franca (ELF) and English as an international language (EIL), have analyzed and documented how prevailing ideologies rooted in "the myth of the native speaker" (Pennycook, 1994; Canagarajah, 1999; Kramsch, 2000), "the native speaker fallacy" (Phillipson, 1992) and associated ideologies generate discrimination and affect students and teachers' sense of self-worth. By making use of telecollaboration to determine how L1 Spanish speaking Colombian EFL pre-service teachers' interactions with U.S. heritage Spanish speakers (HSSs) influence the Colombian future teachers' self-perceptions as (non) native speakers and future teachers, this study responds to scholars' concerns to diversify the scope of explorations on NNESTs (Samimy & Kurihara, 2008; Llurda, 2008). Examining the ideological side of the native vs. non-native speaker dichotomy in telecollaboration, this research seeks to reverse the tendency to study interactants' exchanges mainly as a language feedback process through which "native speakers" support those who are not native speakers. Under an overarching qualitative phenomenological case study research design, the first article's pre-assessment of participants' self-perceptions of (non) nativeness found that the myth of the native speaker, the native speaker fallacy and associated ideologies permeated participants' self-images as language speakers and prospective teachers. Nevertheless, their ongoing education and the perceived benefits of becoming skillful language users contrasted with the harmful effects of these ideologies. Based on findings in the first article, the second study determined that in adopting meaning making abilities as their center of interest in telecollaboration, most participants focused less on the achievement of idealized native speaker abilities. Their interaction with U.S. peers generated confidence in their use of English, self-criticism of their skills in Spanish and a tendency to embrace the idea that they could succeed as English teachers. The intercultural and sociocultural nature of telecollaboration as a potential resource to leverage Colombian prospective teachers' self-perceptions constitutes the core of the last manuscript. Cooperative relationships with U.S. peers provided participants affective and knowledge-based resources to build more favorable views of themselves, attitudes to confront the detrimental effects of nativespeakership ideologies, and informed judgments to dismantle them. The pedagogical implications section discusses the need to revise the current EFL perspective providing the framework for English language teaching and learning in Colombia, avenues for strengthening students' ideological literacy through telecollaborative tasks and the potential integration of telecollaboration in the language teacher education curriculum as a means to increase participants' linguistic, intercultural and pedagogical abilities, and to cultivate more favorable self-images.

The invasive tree-of-heaven, Ailanthus altissima (Miller) Swingle, is widespread and damaging throughout North America. Verticillium wilt disease is emerging as a potentially exciting biological control option for this difficult to control tree. In Virginia, Verticillium nonalfalfae has been confirmed causing significant mortality to A. altissima, while V. dahliae is suspected to be present and causing lower levels of disease. Little else is known regarding these two fungal species in this state. The purpose of this research was to gain a better understanding of how Verticillium wilt impacts A. altissima and its potential as a biological control agent. We first confirmed V. dahliae's presence in Virginia and its pathogenicity to A. altissima using Koch's postulates. We then completed a regional field-inoculation experiment to show that V. nonalfalfae effectively kills and spreads to adjacent A. altissima, regardless of V. dahliae presence or other climate and stand variables. Additionally, we showed that V. dahliae causes lower levels of disease than V. nonalfalfae, and does not spread rapidly. Next, we surveyed all Virginia A. altissima stands known to be naturally infected with V. nonalfalfae to determine whether V. nonalfalfae persists long-term, that it considerably reduces A. altissima numbers, and that its local prevalence may be higher than initially suspected. However, we were unable to infect A. altissima seedlings using soil collected at these infested sites, suggesting that V. nonalfalfae's survival within field soil may be limited. Lastly, using paired A. altissima invaded-uninvaded sites, we found that A. altissima presence is associated with a decreased proportion of native plants and species in the woody and herbaceous understory, but not the germinable seedbank. Furthermore, we found that this impact on the woody understory appears to increase over time, supporting early management actions and helping us predict post-management restoration needs. We conclude that V. nonalfalfae has a high potential of successfully limiting A. altissima throughout Virginia, supporting its registration as a biopesticide. / Doctor of Philosophy / Commonly called the tree-of-heaven, the nonnative invasive forest-tree Ailanthus altissima, is extensive, damaging, and spreading throughout North America. After finding large areas of declining tree-of-heaven being killed by two different fungal species (Verticillium nonalfalfae and V. dahliae), research has been focused on how to use these fungi to help us manage the tree-of-heaven. In Virginia, V. nonalfalfae has been confirmed killing large numbers of tree-of-heaven, while V. dahliae is suspected to be present in areas with lower levels of decline. The purpose of our research was to gain a better understanding of how these pathogens impact tree-of-heaven and their potential as biological control agents in Virginia. We first confirmed that V. dahliae is present in Virginia and can cause disease on tree-of-heaven. We then inoculated tree-of-heaven stands throughout the state to confirm that V. nonalfalfae effectively kills and spreads to adjacent tree-of-heaven regardless of V. dahliae presence or other climate or site variables. In contrast, we found that V. dahliae only causes low levels of disease and does not spread effectively. Next, we surveyed all known naturally infected V. nonalfalfae sites in Virginia and demonstrated that V. nonalfalfae persists long term within these stands, considerably reducing but not eradicating the tree-of-heaven, and that V. nonalfalfae's local prevalence may be higher than initially suspected. However, when tree-of-heaven seedlings were planted into soil collected from these infested sites, no disease developed, suggesting that V. nonalfalfae's survival within the soil may be limited. Lastly, by looking at tree-of-heaven stands, we found that the tree-of-heaven's presence is associated with a lower percentage of native plants and species in the understory, but not in the seeds present in the soil. In addition, we found that this impact on the woody plants in the understory appears to become more severe over time, supporting managing the tree-of-heaven as soon as possible. We conclude that V. nonalfalfae used as a biological control has a good potential of successfully limiting the tree-of-heaven in Virginia and support its registration as a biopesticide.

Master of Science / Department of Biology / Keith B. Gido / Nonnative species represent a major threat to the continued persistence of native fishes globally, especially in the Colorado River Basin of western North America, where there are now more nonnative than native fishes. In the upper Gila River, a tributary of the Colorado, numerous nonnative fishes have established populations, and predation by these nonnatives has been linked to extirpation of native fishes under low-flow conditions at some locations. Historically, the upper Gila lacked a top piscivore, and it is unclear what mechanisms have allowed the establishment of nonnative piscivores and resultant extension in food chain length. To investigate the phenomenon of increased food chain length through nonnative introductions we explored the influence of autochthonous energy availability on nonnative predator abundance, food chain length, and abundance of other trophic levels. Predictions were that increased basal energy availability would lead to increased nonnative predator abundance and thus increased food chain length, based upon predictions from food web theory. Annual production and biomass of four trophic levels measured across six longitudinally-positioned sites were calculated between June 2008 and June 2009 to test these predictions. In addition, energy demand of trophic levels relative to energy supply was compared across sites using a quantitative food web approach, to evaluate energy limitation across trophic levels. Primary production was found to vary considerably across the upper Gila (1,677-16,276 kcal m-2 yr-1), but production and biomass of other trophic levels was not related to this gradient as predicted. In addition, food chain length demonstrated a marginally-significant negative relationship with primary production (R[superscript]2=0.42, d.f.=5, p=0.16), which was in contrast with predicted responses. These results suggest that energy availability does not appear to be a limiting factor to the production or biomass of consumers. The influence of other mechanisms on food chain length in the upper Gila River, in particular disturbance frequency and intensity, deserve further investigation.

Speech often occurs in challenging listening environments, such as masking noise. Visual cues have been found to enhance speech intelligibility in noise. Although the facilitatory role of audiovisual integration for perception of speech has been established in native speech, it is relatively unclear whether it also holds true for speech produced by nonnative speakers. Native listeners were presented with English sentences produced by native English and native Korean speakers. The sentences were in either audio-only or audiovisual conditions. Korean speakers were rated as more accented in audiovisual than in the audio-only condition. Visual cues enhanced speech intelligibility in noise for native English speech but less so for nonnative speech. Reduced intelligibility of audiovisual nonnative speech was associated with implicit Asian-Foreign association, suggesting that listener-related factors partially influence the efficiency of audiovisual integration for perception of speech produced by nonnative speakers. / text

Este trabalho tem como principal objetivo analisar as representações do falante nativo e do falante não-nativo de inglês construídas sob o ponto de vista do aluno brasileiro, e as implicações dessas representações no processo de constituição da identidade desse aluno, que tem o português como primeira língua e aprende inglês como língua estrangeira. Nossa hipótese é que a diferença significativa que se observa na relação entre o aluno brasileiro e falantes nativos, de um lado, e entre o mesmo aluno e falantes não-nativos, de outro, afeta as representações construídas pelo aprendiz, podendo resultar numa tentativa de resistência ao lugar aparentemente fixo ocupado pelo brasileiro enquanto falante não-nativo de inglês. A análise dessas representações baseia-se num corpus constituído por dez entrevistas com alunos brasileiros de inglês de uma escola de idiomas de São Paulo. Nossa pesquisa é embasada nos preceitos teóricos da Análise do Discurso, assim como em conceitos dos Estudos Culturais e da perspectiva psicanalista. Com base na análise da materialidade lingüística do corpus, destacamos representações sustentadas por oposições binárias que, se por um lado, parecem imobilizar o sujeito-aluno na relação com o falante nativo, pelo fato de o aluno brasileiro ser sempre representado como o polo negativo da oposição, por outro, permitem, na relação com o falante não-nativo, vislumbrar a possibilidade de um deslocamento dessas representações associadas ao aprendiz brasileiro. Porém, observamos que esse deslocamento é sempre adiado e não se concretiza devido à força que o falante nativo ainda exerce sobre o aluno brasileiro/falante não-nativo. Concluímos que essas representações fixistas, baseadas em oposições binárias, dificultam a prática de ensino de língua inglesa como um lugar de produção de novos sentidos. Com base nessa conclusão, ressaltamos a importância de uma prática pedagógica que vá além do ensino de inglês como mero instrumento de comunicação, permitindo desconstruir as oposições binárias e contribuir para uma ressignificação do lugar do aprendiz brasileiro/falante não-nativo de inglês em relação ao falante nativo e à língua inglesa. / This work aims at analyzing the representations of native and non-native speakers of English built by Brazilian students, and the implications of these representations to students identity as Portuguese native speakers and learners of English as a foreign language. Our hypothesis is that the significative difference noticed in the relationship between Brazilian students and native speakers of English, on the one hand, and between these students and other non-native speakers, on the other, affects the way Brazilian students represent themselves and other speakers, and may result in an attempt to resist the apparently fixed place occupied by Brazilians as non-native speakers of English. The analysis of these representations is based on a corpus containing ten interviews with Brazilian students of English from a language school in São Paulo. Our work is based upon the theoretical tenets of Discourse Analysis, as well as on concepts from the Cultural Studies and Psychoanalysis. The analysis of the linguistic materiality of the corpus showed representations that were sustained by binary oppositions, which seemed to immobilize the learners in the interaction with native speakers, since the Brazilian student is always represented as the negative pole of the opposition, but also suggested the possibility of dislocation of these representations when the interaction involved Brazilian students and other non-native speakers of English. However, it is argued that this dislocation is always postponed and never takes place because of the power that the native speaker has over the Brazilian student/non-native speaker of English. We concluded that these fixed representations, based on binary oppositions, make it difficult for the English language teaching practice to allow for the production of new meanings. Based on this conclusion, we highlight the importance of a pedagogical practice that goes beyond teaching English merely as a communication tool, by deconstructing binary oppositions and making it possible for the Brazilian student/non-native speaker of English to occupy a new place in the relationship with the native speaker and the English language.

Este trabalho tem como principal objetivo analisar as representações do falante nativo e do falante não-nativo de inglês construídas sob o ponto de vista do aluno brasileiro, e as implicações dessas representações no processo de constituição da identidade desse aluno, que tem o português como primeira língua e aprende inglês como língua estrangeira. Nossa hipótese é que a diferença significativa que se observa na relação entre o aluno brasileiro e falantes nativos, de um lado, e entre o mesmo aluno e falantes não-nativos, de outro, afeta as representações construídas pelo aprendiz, podendo resultar numa tentativa de resistência ao lugar aparentemente fixo ocupado pelo brasileiro enquanto falante não-nativo de inglês. A análise dessas representações baseia-se num corpus constituído por dez entrevistas com alunos brasileiros de inglês de uma escola de idiomas de São Paulo. Nossa pesquisa é embasada nos preceitos teóricos da Análise do Discurso, assim como em conceitos dos Estudos Culturais e da perspectiva psicanalista. Com base na análise da materialidade lingüística do corpus, destacamos representações sustentadas por oposições binárias que, se por um lado, parecem imobilizar o sujeito-aluno na relação com o falante nativo, pelo fato de o aluno brasileiro ser sempre representado como o polo negativo da oposição, por outro, permitem, na relação com o falante não-nativo, vislumbrar a possibilidade de um deslocamento dessas representações associadas ao aprendiz brasileiro. Porém, observamos que esse deslocamento é sempre adiado e não se concretiza devido à força que o falante nativo ainda exerce sobre o aluno brasileiro/falante não-nativo. Concluímos que essas representações fixistas, baseadas em oposições binárias, dificultam a prática de ensino de língua inglesa como um lugar de produção de novos sentidos. Com base nessa conclusão, ressaltamos a importância de uma prática pedagógica que vá além do ensino de inglês como mero instrumento de comunicação, permitindo desconstruir as oposições binárias e contribuir para uma ressignificação do lugar do aprendiz brasileiro/falante não-nativo de inglês em relação ao falante nativo e à língua inglesa. / This work aims at analyzing the representations of native and non-native speakers of English built by Brazilian students, and the implications of these representations to students identity as Portuguese native speakers and learners of English as a foreign language. Our hypothesis is that the significative difference noticed in the relationship between Brazilian students and native speakers of English, on the one hand, and between these students and other non-native speakers, on the other, affects the way Brazilian students represent themselves and other speakers, and may result in an attempt to resist the apparently fixed place occupied by Brazilians as non-native speakers of English. The analysis of these representations is based on a corpus containing ten interviews with Brazilian students of English from a language school in São Paulo. Our work is based upon the theoretical tenets of Discourse Analysis, as well as on concepts from the Cultural Studies and Psychoanalysis. The analysis of the linguistic materiality of the corpus showed representations that were sustained by binary oppositions, which seemed to immobilize the learners in the interaction with native speakers, since the Brazilian student is always represented as the negative pole of the opposition, but also suggested the possibility of dislocation of these representations when the interaction involved Brazilian students and other non-native speakers of English. However, it is argued that this dislocation is always postponed and never takes place because of the power that the native speaker has over the Brazilian student/non-native speaker of English. We concluded that these fixed representations, based on binary oppositions, make it difficult for the English language teaching practice to allow for the production of new meanings. Based on this conclusion, we highlight the importance of a pedagogical practice that goes beyond teaching English merely as a communication tool, by deconstructing binary oppositions and making it possible for the Brazilian student/non-native speaker of English to occupy a new place in the relationship with the native speaker and the English language.