Tesis sobre el tema "Contrastive stress"

The production of contrastive stress was studied in normal-hearing and severely and profoundly hearing-impaired children. A picture description task was used to elicit utterances. Contrastive stress was assigned by changing one element in the second and third pictures in sets of three pictures. Stress production was assessed perceptually and acoustically. The normal-hearing and the severely hearing-impaired children were judged to have consistently stressed the element that was changed in the pictures. Some of the profoundly hearing-impaired subjects were judged to have stressed the changed element more often than chance but some did not perform above chance. Acoustic measurements indicated that only the normal-hearing speakers significantly varied both duration and fundamental frequency when stressing words while some of the hearing-impaired children varied only duration. These findings were interpreted as indicating that profoundly hearing-impaired speakers had difficulty producing recognizable contrastive stress and showed deviations in the duration and fundamental frequency of their utterances.

Key aspects of prosody have been studied in adults for a number of years; however, less attention has been paid to the acoustic patterns of prosody in children. Thus, the purpose of the present study was to evaluate how a group of 20 pre-adolescent children use prosody to mark contrastive stress compared to a control group of adult speakers. It was of interest to investigate whether the children's use of prosody differed between boys and girls or the part of speech being emphasized. The prosodic patterns of contrastive stress were evaluated in terms of duration, fundamental frequency, and intensity change relative to a baseline production of the same sentence. In addition, a perceptual experiment was conducted to determine if listeners could reliably identify the gender of the child speakers when listening to sentence length utterances. Statistical analysis indicated that there were some differences in the duration and fundamental frequency change as a function of speaker age and the part of speech being emphasized, with relatively minor differences between genders. However it remains unclear if the acoustic differences found in this study were substantial enough to cause a salient perceptual difference. Although previous studies have identified increases in frequency, intensity, and duration as cues of contrastive stress, the present findings revealed patterns that did not consistently conform to these expectations. Limitations in the task design, individual speaker characteristics, and also the type of acoustic measure used may have contributed to these results.

The influence of information structure on tonal scaling in German is examined experimentally. Eighteen speakers uttered a total of 2277 sentences of the same syntactic structure, but with a varying number of constituents, word order and focus-given structure. The quantified results for German support findings for other Germanic languages that the scaling of high tones, and thus the entire melodic pattern, is influenced by information structure. Narrow focus raised the high tones of pitch accents, while givenness lowered them in prenuclear position and canceled them out postnuclearly. The effects of focus and givenness are calculated against all-new sentences as a baseline, which we expected to be characterized by downstep, a significantly lower scaling of high tones as compared to declination. The results further show that information structure alone cannot account for all variations. We therefore assume that dissimilatory tonal effects play a crucial role in the tonal scaling of German. The effects consist of final f0 drop, a steep fall from a raised high tone to the bottom line of the speaker, H-raising before a low tone, and H-lowering before a raised high tone. No correlation between word order and tone scaling could be established. 2008 Elsevier Ltd. All rights reserved.

Contrastive stress is an aspect of communication that can be used to highlight information, de-accent redundant information, and create distinctions between new and previously-provided information. Previous research has documented that adult speakers use relative changes in their vocal intensity, fundamental frequency (F0), and duration to mark contrastive stress in a sentence. However, less is understood about how and when children mark contrastive stress in their communication, thus the current study aims to examine a number of acoustic elements of contrastive stress in 8 to 10-year-old children. Speech samples were elicited from 20 children and analyzed to determine if the acoustic parameters of F0, intensity, and duration varied as a function of the speaking condition, speaker gender, or grammatical unit. Results of the experiment suggest that when comparing the baseline speaking condition to the speaking condition eliciting contrastive stress, significant differences were only found for the acoustic measure of mean intensity. Additionally, gender-related differences in contrastive stress were found only for the dependent measure of F0 slope, with a greater F0 slope exhibited by female speakers. All grammatical units were significantly different from one another across a number of variables, with significant interactions between baseline and target conditions and grammatical unit being analyzed. As indicated in previous research, the findings of the present study may indicate that children under 10 years of age may not have developed contrastive stress in an adult-like manner. Results may also be due to individual speaker differences, the complex nature of prosody, or measurement methodology.

Suspended and epiphytic bacteria were studied in calcareous headstreams of the Yorkshire Wolds and in acid headstreams of the Galloway Hills. Mean concentrations of suspended bacteria were marginally greater in the calcareous streams, while heterotrophic activity was substantially greater. Mean cell volume was also greater. The concentration and activity of suspended bacteria in the calcareous streams usually showed linear downstream increase, while in the acid streams, the downstream increase was less, and was frequently not observed. In Mill Beck (a calcareous stream) it was found that the population of epiphytic bacteria near the source was easily sufficient to sustain the observed downstream increase in suspended bacteria. In Dungeon Burn (an acid stream) a substantial population of epiphytic bacteria was also found, but there was no downstream change in concentration of suspended bacteria; reasons are suggested for the apparent non-release of epiphytes in the Galloway stream. The mean volume of suspended bacteria in Mill Beck changed between the source and downstream limit of a vegetated section, to resemble that of epiphytic bacteria, suggesting that suspended bacteria were dislodged epiphytes. Estimates were made of the attachment rate of suspended bacteria to submerged vegetation in Mill Beck; daily attachment represented only a small proportion of the total standing crop of epiphytic bacteria. A further study in Mill Beck, over a Spring growing period, demonstrated a temporal change in the density of epiphytic bacteria, which was related to change in discharge and temperature. The results supported the suggestion that epiphytic bacteria might largely be the source of suspended bacteria in this headstream.

A series of experiments was carried out in the Department of Agriculture, University College of North Wales, Bangor, during October 1987 to September 1989. The purpose of these was to study the effects of water stress and salinity stress at different stages on long (Norman), medium (Fenman) and short duration (Wembley) wheat varieties in different environments. Effects of water stress were tested in large pots in different types of soil. Effects of salinity were tested by growing plants in solution culture. In both experiments water stress and salinity stress were imposed at three major stages, tillering to stem extension (TL-SE), stem extension to booting (SE-BG) and booting to maturity (BG-MT). These were tested in each variety in comparison with a control of each variety. Growth measurements, leaf number and area, stem area, shoot number, plant height, nitrogen %, nitrogen uptake, dry weight per plant were determined at the end of each stage. Soluble carbohydrates were determined at anthesis. This was done to find out how much these growth measurements were decreased during each stress period. Yield and yield components were determined at harvest. In these experiments the long duration variety took a long time in growth during TL-SE, in comparison to mid winter and spring wheat varieties. The long duration variety gave a higher plant, more straw dry weight production and more leaf number than the short duration variety. The long duration variety also gave a higher yield than the medium and short duration varieties, due to larger ears, more spikelets vi per ear, more grain number per ear and more grain number per spikelet. All varieties experienced higher temperatures and longer days during SE-BG and BG-MT in both experiments. The lengths of these stages therefore showed smaller variation between varieties. In water stress experiments the mixed peat-soil used in Experiment 2 dried out quicker than the normal field soil used in Experiment 1. The upper portion of the soil was dried before the lower portion of the soil during the stress period. With water stress at SE-BG and BG-MT the soil dried out quicker in both years. Gypsum blocks were used to give readings of water stress. with water stress at BG-MT the soil was completely dried out after the third week, in all varieties, due to higher plant height, higher temperature and more evaporation. Because of this water stress at BG-MT resulted in a short duration for ripening. In both water stress Experiments 1 and 2, in all varieties all water stress treatments decreased the growth measurements, decreased yield and yield components. In Norman water stress at TL-SE had a long stress period due to slow growth processes during cold winter. However, this stage had a similar effect on yield in Norman, Fenman and Wembley. In both water stress experiments in all varieties, water stress at SE-BG caused the largest reductions in growth measurements, because at this stage the plant had the greatest leaf area and temperature was higher, although the period of stress was only a few weeks. However, water stress at BG-MT caused the greatest decreases in yield. This stage showed the greatest vii decreases in yield and yield components, due to small grain size, fewer fertile spikelets, small size of ear, earlier leaf senescence, short duration for ripening, higher temperature, lack of soluble carbohydrate for grain f~lling from stem and pollination problems at anthesis time. In both salinity Experiments 1 and 2, all varieties had a larger green leaf area, more tillers and all varieties were much stronger after stem extension than in the water stress experiments due to the solution culture teChnique. Norman was more strong than the other varieties because of its long period grown in solution culture. Salinity at TL-SE was more damaging than other stages in all varieties. Salinity at TL-SE decreased the growth measurements, such as leaf area, stem area, plant height, dry weight per plant. Because of the growth measurement reduction, grain weight per plant, grain number per plant, grain number per ear, grain number per fertile spikelet and fertile spikelet per ear were decreased by salinity at this stage. Salinity at SE-BG and BG-MT also decreased growth measurements, decreased grain yield and yield components. Salinity at BG-MT decreased grain yield and yield components more than salinity at SE-BG. In Experiment 2 in all varieties with salinity at BG-MT plants were harvested a few days before other stages and the control. Norman was more sensitive with salinity at TL-SE than the other varieties because of its long period grown under salt stress. Norman was much stronger with salinity at SE-BG. Norman gave lower yield, yield components at BG-MT than other varieties at this stage.

Nitrogen (N) fertilization and drought stress have large influence on maize grain yield, thus studies about genotypes and management technologies are very important to increase maize production. This study is presented in three chapters; the first two were undertaken in the United States of America and the third one in Brazil. The following objectives are addressed in this order: (1) The primary objective was to understand which traits, if any, differ between similar-maturity tolerant and non-drought tolerant hybrids that govern nutrient uptake and concentrations under different management treatments (varied plant densities (PD) and N rates) and their influence on grain yield (GY). (2) The primary objective was to investigate the physiological and yield responses of comparable-maturity drought and non-drought tolerant hybrids (P1151 vs. P1162, and P1498 vs. 33D49) to varied plant density and N rates. (3) The main objective was to investigate the responses of maize to sidedress N applications, using isotopically labeled urea fertilizer (15N), at different development stages. The secondary objective was to verify the correlations between the chlorophylls and carotenoids with SPAD index (evaluated at V14 and V16) and all these parameters with total biomass (BM), harvest index (HI), GY and grain N content. The major results for objectives 1 and 2 were as follows: All hybrids had similar GY responses to PD (near 79,000 versus near 100,000 plants ha-1) and N rate (from 0 to 269 kg N ha-1) treatment factors. Hybrid 1 (AQUAmax(TM) P1151) demonstrated similar leaf photosynthetic (A) and transpiration (E ) rates than its non-drought tolerant counterpart of similar maturity since Hybrid 2 (P1162) had a higher leaf area Index (LAI) (at the R2 and R3 stages) and a similar GY as Hybrid 1. Hybrid AQUAmax(TM) P1498 maintained higher leaf A and E rates than P33D49 during the grain-fill period, thus perhaps demonstrating improved persistence in root water uptake late in the season. There was no single trait differentiation in photosynthesis or transpiration between drought and non-drought tolerant hybrids. Highest BM and GY at maturity generally followed shorter anthesis-silking intervals and more stover macronutrient (P and S) accumulation, in the drought season, so these characteristics appeared to be important drought-tolerant mechanisms regardless of hybrid designations. The major findings from the objective 3 investigations: Maize crop responded similarly for GY to timing of sidedress N application. Grain N content from 15N fertilizer and N uptake and efficiency were greater for early N applications. SPAD values correlated positively with most pigment variables at V16 in both seasons, thus proving that SPAD was an efficient instrument of indirect evaluation of chlorophylls and carotenoids in maize leaves at early stages. Chlorophyll b at V16, sample stage, was positively correlated (P<0.05) with grain N content, GY, and BM, and total chlorophyll at V16 was positively correlated with GY and grain N content. However the chlorophylls a and total, evaluated at V14, were negatively correlated with GY. So, measurement chlorophyll and carotenoid pigment contents should be done after V14 stage when studies aim to evaluate crop nutritional conditions and prescribe future grain production practices.
Adubação nitrogenada (N) e o estresse hídrico tem grande influência no rendimento de grãos de milho, assim, estudos sobre genótipos e o manejo dessa cultura são muito importantes para o aumento da produtividade. Este estudo é apresentado em três capítulos. Os dois primeiros foram desenvolvidos nos Estados Unidos e o terceiro no Brasil. Os objetivos são apresentados na seguinte ordem: (1) o objetivo principal foi entender quais características, se existirem, diferem entre híbridos tolerantes e não-tolerantes à seca, com semelhança em maturidade, que regem a absorção de nutrientes e concentrações destes sob diferentes tratamentos de cultivo e sua influência na produção de grãos. (2) O objetivo principal foi investigar as respostas fisiológicas (fotossíntese (A) e transpiração (E)) e a produção de milho em genótipos, com semelhante maturidade, tolerantes e não tolerantes ao déficit hídrico (P1151 vs. P1162 e P1498 vs. 33D49) em relação a variação de densidade de plantas e doses de N. (3) O principal objetivo foi investigar as respostas de milho à aplicação de nitrogênio em cobertura, ureia fertilizante (15N), em diferentes estádios fenológicos. O objetivo secundário foi: verificar a correlação entre as clorofilas e carotenoides com SPAD (avaliado em V14 e V16) e destas com a biomassa total (BM), índice de colheita (IC), produção de grãos (PG) e do conteúdo de N nos grãos. Como resultados: (1 e 2) Todos os híbridos responderam de forma semelhante para para PG em relação aos tratamentos. O Híbrido P1151 demonstrou semelhantes A e E e menor area foliar do que seu semelhante em maturidade (P1162). Híbrido P1498 pareceu ser capaz de manter a taxa de transpiração foliar e de fotossíntese mais elevadas do que 33D49, durante o período de enchimento de grãos. Este híbrido apresentou uma melhor persistência na captação de água pela raiz no final da estação de cultivo. Geralmente maiores BM e PG na maturidade foram relacionadas a menores intervalos de diferenciação floral e a maior acumulação, na estação seca, de macronutrientes (P e S) no colmo, sendo as ultimas características consideradas como mecanismos de tolerância à seca. (3) A cultura do milho respondeu de forma semelhante em relação a PG à aplicação de N. O teor de nitrogênio nos grãos derivado do 15N fertilizante e a eficiência de uso do fertilizante nitrogenado foram maiores em relação a aplicação de N nos primeiros estádios. Houve correlação positiva e siginificativa para SPAD com a maioria dos pigmentos no estádio de avaliação V16. Provando ser um instrumento eficaz de avaliação indireta de clorofilas e carotenóides em estágios iniciais. A clorofila b, avaliada em V16, apresentou correlação positiva significativa (p<0,05) com teor de N nos grãos, PG, e BM, a clorofila total em V16 também apresentou uma correlação positiva com o teor de N nos grãos, no entanto, as clorofilas a e total, avaliadas em V14, apresentaram correlação negativa com PG. Assim, a medição do teor de pigmentos com o objetivo de estudar as condições nutricionais e previr a produção de grãos deve ser realizada após o estágio V14.

Traumatic incidences happen all around the globe. Some of the people who experience trauma develop post-traumatic stress disorder (PTSD), while some do not. Even more interesting is that some also experience growth afterwards (post-traumatic growth; PTG). The purpose of this paper is to look at neural aspects of why some people develop PTSD and others PTG after a traumatic event. To fulfill the aim, both PTSD and PTG will be reviewed to create an image of the existing research in behavioral and neurological terms. In addition to looking at the constructs separately, a chapter will also look at studies where both PTSD and PTG are acknowledged collaterally in participants. When looking deeper into the theories of PTSD divisions occur, and more research is needed to establish the most prominent explanation of PTSD. PTG on the other hand has only been studied for a short period of time but yields important insights into trauma-related outcomes. These fields need to be submerged and new multidisciplinary definitions are needed for future research. The key to PTSD is suggested to emerge within the new field.

>Magister Scientiae - MSc
Salvia hispanica L. is an annual pseudocereal food crop, locally known as chia that has the ability to grow in water stress environments. The importance of chia dates back to the pre-columbian era where it was consumed as staple food by the indigenous South Americans due to its high nutritional and medicinal benefits. A single chia plant produces two seed variants: white seed genotype (denoted as WSG) and black seed genotype (denoted as BSG). Chia seeds have been proven to have a huge potential as a healthy food source and contained various medicinal properties. However, these plants are still prone to environmental stress conditions such as salinity that is one of the major abiotic stresses that influence crop production and yield worldwide. Despite the nutritional impact of the chia seeds, limited information regarding their molecular responses to abiotic stress conditions are known. This study was divided into two distinct parts. Firstly, the study comparatively analysed the leaf proteomes of two chia genotypes using gelbased proteomic analysis coupled with mass spectrometry. Total soluble proteins were extracted from chia leaves and subjected to 2-D PAGE analysis. Proteins were visualized by CBB and identified by MALDI-TOF MS/MS. A total of 284 and 209 spots were detected in WSG and BSG, respectively. Using mass spectrometry, 36 differentially expressed protein spots were successfully identified based on their protein abundance using homology database searches. Interestingly, two defensive-related proteins (osmotin-like protein and the chalcone isomerase) were only present in WSG and absent in BSG. In light of previous information regarding the nutritional profiles (no significant difference) of these two genotypes, this study has shown that there are distinct molecular differences between these genotypes. Therefore, WSG will be used in further downstream analysis. The second part of this study focused on the influence of salt stress (imposed by 100 mM NaCl) on the leaf proteome of WSG. Using gel-based proteomic analysis, 61 differentially expressed proteins were identified and classified into nine functional categories. Most of the proteins identified in this study were upregulated by salt stress. Interesting to note, 12 proteins identified in this study were only present in response to salt stress but were absent in the control. These proteins include ATP-dependent zinc metalloprotease FTSH 2 (spot 48), HSP70 proteins (spots 46 and 47), superoxide dismutases (spots 10, 41 and 42) and an ascorbate peroxidase (spot 56). All these proteins are important antioxidants that play a significant role in scavenging reactive oxygen species (ROS). Previous studies have shown that these antioxidants play vital roles in stress tolerance. These proteins could serve as potential biomarkers that could be used to enhance salt stress tolerance in pseudocereals and cereal food crops.
National Research Foundation (NRF) and Agricultural Research Council

Turgor regulation is the process by which walled organisms alter their internal osmotic potential to adapt to osmotic changes in the environment. Much of what we know regarding turgor regulation and osmotic adjustment in algae is limited to the green characean and chlorphytan algae. This thesis is an investigation of turgor regulation in two species of the yellow-green xanthophycean alga, Vaucheria. The first part of this study involved the collection and identification of species of Vaucheria from contrasting habitats in New Zealand. Seven species of Vaucheria were identified based on the morphology of their reproductive structures. Two were described as new species (V. aestuarii and V. edaphica) and two others were reported for the first time from New Zealand (V. erythrospora and V. litorea). The genetic variation and phylogenetic position of these species were studied using phylogenetic analyses of rbcL sequences. Two of the species from contrasting habitats were selected for a comparative study on turgor regulation. These were Vaucheria erythrospora, isolated from an estuarine habitat, and Vaucheria repens, isolated from a freshwater habitat. Using a single cell pressure probe to directly measure turgor after hyperosmotic shock, V. erythrospora was found to recover turgor after a larger shock than V. repens. Threshold shock values for this ability were > 0.5 MPa for V. erythrospora and < 0.5 MPa for V. repens. Recovery was more rapid in V. erythrospora than V. repens after comparable shocks. Growth studies showed that V. erythrospora was able to grow and maintain turgor over a wider range of NaCl concentrations. These responses are thought to underlie the ability of V. erythrospora to survive in an estuarine habitat and restrict V. repens to freshwater. xi The final part of this study investigated the mechanisms underlying turgor regulation in V. erythrospora. Different responses were observed depending on whether NaCl or sorbitol was used to elicit the shock. Membrane potential (Em) measurements showed a rapid depolarization of the plasma membrane in response to a NaCl-induced hyperosmotic shock, followed by a slower repolarization, and recovery almost back to the resting Em. MIFE recordings indicate a net K+ efflux, a response that has been reported in other systems. While recordings of Na+ fluxes were not possible due to the high external Na+, these may account for the depolarisation and recovery of turgor as turgor recovery was inhibited by the non-selective cation channels (NSCCs) inhibitor Gd3+ and was dependant on the external Na+ concentration. An equivalent sorbitol-induced hyperosmotic shock hyperpolarized the Em, followed by depolarization and recovery back to the resting Em. Net flux recordings showed that both K+ and Na+ were taken up in response to a sorbitol shock when there was a low external Na+ concentration (1mM). K+ was possibly taken up through inward rectifying K+ channels activated by membrane hyperpolarization. The ability of V. erythrospora to rapidly regulate turgor by taking up ions during hyperosmotic stress is the possible reason for its survival in an estuarine habitat.

Made available in DSpace on 2015-03-26T13:36:41Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1640977 bytes, checksum: 4fdd6a8d2b89afc2024e929b0c838240 (MD5) Previous issue date: 2010-11-22
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Os metais pesados, especialmente o cádmio, têm se tornado um dos principais agentes de estresse abiótico em plantas superiores em função de sua alta toxicidade e aumento dos níveis de liberação no meio ambiente. Apesar toxicidade destes elementos, as plantas desenvolveram mecanismos que lhes conferem aumento na tolerância a esta condição de estresse através de adaptações físicas e ativação de uma rede integrada de respostas celulares e moleculares que começam a atuar após o início do estresse. Relatos de alterações fito hormonais durante o processo de aclimatação ao Cd envolvendo o ácido abscísico (ABA) são escassos na literatura, e os poucos existentes são relativos a toxicidade aguda, uma situação distinta daquela que normalmente ocorre no meio ambiente. Em vista disso, esta pesquisa propôs-se a elucidar um potencial papel do ABA sobre os mecanismos bioquímicos e fisiológicos de aclimatação e tolerância ao estresse crônico por Cd, utilizando para tanto o tomateiro mutante notabilis deficient em ABA, uma linhagem transgênica complementada notabilis complemented 13, e seu tipo selvagem. Um padrão de resposta distinta das plantas notabilis pode ser apontado pelo aumento da absorção de Cd, uma elevada taxa de transpiração e redução do potencial hídrico foliar, combinado a inalterações da taxa de concentração de CO2 entre a câmara sub- estomática e a ambiente (Ci/Ca), e da composição isotópica de carbono (δ13C), além de redução da condutância estomática (gs) e da eficiência do uso da água (WUE), sob tratamento com este metal pesado. Apesar da maior atividade das enzimas antioxidantes superóxido dismutase (SOD) e catalase (CAT) na ausência de Cd, notabilis teve maior peroxidação lipídica em suas raízes. Limitações da gs causadas pelo Cd aparentam ser o principal motivo da redução da taxa líquida de assimilação de carbono (A) em plantas do tipo selvagem e notabilis complemented 13, ao passo que notabilis apresenta várias alterações negativas nos parâmetros fotoquímicos da fotossíntese, implicando em uma redução transitória no potencial de absorção da luz, reduzida conversão de energia para fotoquímica, e maior perda regulada de energia no fotossistema II, que podem explicar, pelo menos em parte, a redução da A. A complementação do mutante demonstrou recuperação do fenótipo para vários parâmetros para um patamar semelhante ao das plantas do vi tipo selvagem, reforçando a hipótese que a síntese de ABA desempenha um papel chave na aclimatação das plantas ao metal.
Heavy metals, especially cadmium have become one of the main abiotic stress agents for higher plants because of their high toxicity and increasing levels released in the environment. Despite the poisonous of these elements, plants have evolved mechanisms by which they increase their tolerance to this stress condition through both physical adaptations and activation of an interactive network of cellular and molecular responses that begin after the onset of stress. Information about phytohormonal changes during the Cd acclimation process involving abscisic acid (ABA) are scarce in literature, and the few existent depict the acute toxicity, a distinct situation from that which normally occurs in the environment. In view of that, this research purposed to find out a potential role of ABA on physiological and biochemical acclimation mechanisms and tolerance to chronic Cd stress, using the tomato plants ABA-deficient mutant notabilis, a transgenic complemented line notabilis complemented 13, and their wild type. A different response pattern of notabilis plants could be pointed due increased Cd uptake, an elevated transpiration rate and reduced leaf water potential, combined with unaltered sub-stomatal- toambient CO2 concentration ratio (Ci/Ca) and carbon isotopic composition (δ13C), a reduced effect on stomatal conductance (gs), and on water use efficiency (WUE) under treatment with this heavy metal. Despite the higher activity of the antioxidative enzymes superoxide dismutase (SOD) and catalase (CAT) in absence of Cd, notabilis have higher lipid peroxidation in their roots. Limitations in gs caused by Cd appear to be the main reason of reduction in net carbon assimilation rate (A) of wild type and notabilis complemented 13 plants, whereas notabilis has several negative changes in photosynthesis photochemistry parameters that implicate in transient reduction in light absorption potential, lower photochemical energy conversion, and increased energy loss in photosystem II through a regulated non-photochemical mechanism that may explain, at least in part, the reduction in A. The complementation of the mutant showed to recovery several phenotype parameters close to wild type plants, strengthening the hypothesis that ABA synthesis has a key function in plant acclimation to Cd.

A nefropatia induzida por contraste (NIC) é uma lesão renal aguda (LRA) tóxica, que consiste em vasoconstrição intra-renal, toxicidade tubular direta com liberação de espécies reativas de oxigênio (EROs). A NIC está diretamente associada a doenças crônicas que comprometem a oxigenação da região da medula renal, como a disfunção renal preexistente, o Diabetes Mellitus (DM) e insuficiência cardíaca congestiva. Esse estudo investigou os mecanismos fisiopatológicos que caracterizam a NIC em ratos diabéticos. Foram utilizados ratos Wistar, adultos e machos. No protocolo DM foi realizada a nefrectomia unilateral esquerda (Nefré) no 1º dia, para potencializar o efeito tóxico da hiperglicemia crônica no rim. O DM foi induzido pela administração intravenosa (i.v.) de 65 mg/kg de estreptozotocina (STZ, diluída com citrato) no 20º dia, e o contraste iodado (CI) ioxitalamato de meglumina, 6 ml/kg, foi administrado (intraperitoneal, i.p.) no 85º dia. Foram realizados os seguintes grupos: Citrato (controle); Nefré+Citrato; DM; Nefré+DM; DM+CI; Nefré+DM+CI. Foram avaliados parâmetros fisiológicos (ingestão de ração e água, peso, glicemia capilar, peso do rim e peso relativo do rim); a albuminúria (método de imunodifusão), a função renal (FR) (clearance de creatinina, método de Jaffé), a lesão oxidativa (peróxidos urinários-PU, FOX-2; substâncias reativas com o ácido tiobarbitúrico-TBARS, tióis no tecido renal) e análise histológica renal (lesão tubulointersticial). Observou-se que os grupos diabéticos apresentaram polifagia, polidipsia, hiperglicemia e redução do peso corporal (p<0,05), além de redução do clearance de creatinina com elevação de PU e TBARS, manutenção de tióis e elevação da albuminúria. O tratamento com CI nos animais diabéticos determinou redução da FR, elevação dos PU e TBARS e redução dos tióis. Quanto à histologia renal, demonstrou-se que apenas o grupo Nefré+DM+CI apresentou lesão tubulointersticial. Os achados dessa investigação confirmaram o efeito tóxico do CI dose única sobre a função renal de ratos com hiperglicemia crônica, pressupondo que o DM seja fator de risco para essa nefropatia.
Contrast-Induced Nephropathy (CIN) is a toxic acute kidney injury (AKI) that consists in intrarenal vasoconstriction, direct tubular toxicity with generation of reactive oxygen species (ROS). The CIN is associated with the decreased tissue oxygen tension in renal medula in preexisting renal dysfunction, Diabetes Mellitus (DM) and congestive heart failure. This study investigated the pathophysiologic mechanisms in the CIN in diabetic rats. Adult, male, Wistar rats were used. It was performed left uninephrectomy (Nx) on the 1st day in the DM group to potentialize the toxic effect of the chronic hyperglycemia. The DM was induced by a single dose of intravenous streptozotocin (65mg/kg i.v.) in sodium citrate buffer, on the 20th day and the iodine contrast (IC) meglumine ioxithalamate 6 ml/kg was administrated (intraperitoneal, i.p.) on the 85th day. Animals were divided into the following groups: Citrate (control); Nx+Citrate; DM; Nx+DM; DM+IC; Nx+DM+IC. Physiological parameters (water and food intake, body weight, blood glucose, kidney weight and relative kidney weight); renal function (creatinine clearance, Jaffé method); urine albumin (imunodifusion method); oxidative injury (urinary peroxides, FOX-2, tiobarbituric acid reactive substances-TBARS and thiols in renal tissue) and kidney histological analysis (tubulointerstitial injury) were evaluated. In the diabetic groups, polyphagia, polydipsia, increased blood glucose and reduced body weight were observed (p<0.05). The relative kidney weight was increased in the Nx and IC animals (p<0.05). The renal function was reduced; urinary peroxides and TBARS were increased in the diabetic and IC animals. The decrease in thiols levels in the diabetic and IC groups demonstrated the endogenous substrate consumption. The Nx animals that received IC presented tubular cells vacuolization and edema with moderate injury. The data has described the pathophysiology of CIN in diabetic rats involving oxidative injury that resulted of association of chronic high blood glucose and IC toxicity, suggesting that DM can be pointed out as a risk factor for CIN.

This study investigated the diet and growth of a leaf-eating caddisfly, Pycnopsyche, in streams draining a >60 year-old reference forest and a 16-year-old c1earcut (disturbed) forest at Coweeta Hydrologic Laboratory in southwestern North Carolina. The objective was to examine whether Pycnopsyche larvae grew better on fast-decaying leaf types more prevalent in the disturbed streams (e.g., black birch) because leaf-eating insects (shredders) in a previous study were more productive in these streams despite having less food available. Larvae consumed mostly unidentified plant material in streams of both forest types over three seasons (fall, winter, and spring) which suggested larvae did not consume higher quality foods (e.g., algae) in disturbed streams. When fed 2-mo "conditioned" black birch and white oak leaves, lab experiment larvae grew significantly faster on birch leaves. However, when larvae were fed the same leaf types after 3 mo of conditioning, larvae grew significantly faster on oak leaves. A field growth experiment conducted for 42 d using leaf diets representative of both forest types and conditioned for 2 mo found Pycnopsyche grew better on the diet representative of the reference forest. found Pycnopsyche grew better on the diet representative of the reference forest.
Master of Science

Streams along the Copper River Delta, southcentral Alaska, exhibit contrasting thermal and hydrologic variability associated with being primarily groundwater-fed (GWF) or surface water-fed (SWF). Groundwater-fed streams are predictable both thermally and hydrologically year round, whereas SWF streams are unpredictable and exhibit more variable thermal and hydrologic regimes. These differences may strongly influence aquatic insect community structure and secondary production. Four streams, two GWF and two SWF, were sampled twice monthly from late April 2013 through August 2013 and once seasonally in fall (September) and early winter (November). Aquatic insect community structure differed markedly in both hydrologic types. Taxa richness was significantly higher in SWF (43) than in GWF (39) streams and non-metric multidimensional scaling of community structure revealed two distinct groups corresponding to the two hydrologic types. Total secondary production was higher in GWF than in SWF streams with Orthocladiinae (Diptera: Chironomidae) representing 56% of insect secondary production in GWF streams. Results from this study have strong implications for aquatic insect communities in GWF and SWF streams because of differing susceptibilities of these systems to the potential effects of climate change. Due to their thermal stability, groundwater-fed streams are less likely to be impacted by climate change, whereas SWF streams are thermally variable and more likely to be influenced. The effects of altered aquatic insect communities can cascade to higher trophic levels such as salmon and ultimately impact stream ecosystem function and the ecosystem services they provide.

This work deals with the issue of nativization. That is to say we observe the interference caused by the phonological system of Brazilian Portuguese, especially about the stress, on the pronunciation, by native speakers of Portuguese, of some terms of English. The words in question were drawn out of the technical lexicon of Informatics and six people taken part in the research, by a reading of a text with the words drawn out. The description and specific analysis of the transfer of traits of the native system to the pronunciation of the loanwords, mostly to explain the differences between the two phonological inventories, is founded on the presuppositions and concepts of the Standard Generative Phonology and Autosegmental Phonology. When we refer to phenomena related to the syllabic structure and the stress pattern, the framework utilized is that of the Metrical Phonology.
Este trabalho trata da questão da interferência que o sistema fonológico de uma língua nativa causa na pronúncia de termos de uma língua estrangeira que foram nativizados. Procura observar a interferência do sistema fonológico do Português Brasileiro, especificamente quanto ao padrão acentual, na pronúncia, por falantes nativos do Português, de termos do Inglês recortados do vocabulário técnico de informática. Seis informantes participaram da pesquisa, dois do sexo feminino (uma com formação de segundo grau e outra com formação de terceiro grau) e quatro do sexo masculino (dois com formação de segundo grau e dois com formação de terceiro grau). Eles leram um texto contendo as palavras do corpus, que foram transcritas para uma análise posterior. Para a análise dos fatos observados levaram-se em conta os pressupostos da fonologia métrica para explicar os fenômenos referentes ao contraste entre os padrões acentuais das duas línguas. Os resultados da pesquisa indicam que a interferência se dá pelo fato de elas possuírem diferentes padrões acentuais, especialmente quando a noção de extrametricidade é invocada pelo algoritmo de colocação do acento. Observou-se, ainda, que processos de ressilabificação pela inserção de uma vogal epentética [ i ] em sílabas das palavras estrangeiras que ferem as combinações fonotáticas do Português são recorrentes nas pronúncias de todos os informantes, independentemente do grau de contato desses falantes com o Inglês enquanto língua aprendida, o que acarreta mudança no padrão acentual.

L’agrégation des hématies est d'un paramètre essentiel du comportement rhéologique non-newtonien du sang et a fait l'objet d'un grand nombre de recherches méthodologiques, expérimentales et cliniques. Toutefois, les mécanismes de formation des rouleaux et des agrégats en présence de macromolécules endogènes ou exogènes sont très complexe et de nombreux points restent encore à élucider tant sur le plan des aspects fondamentaux que des approches méthodologiques. Notre travail de thèse a comporté plusieurs types d'action qui ont été menées parallèlement: deux actions méthodologiques visant à améliorer la quantification de l'agrégation érythrocytaire et à approcher lors d'investigations in vitro les d'agrégation qui pourraient être observées in vivo. C’est ainsi que nous avons été amené à étudier le rôle d'un cisaillement pulsé sur la cinétique de formation des rouleaux dans des conditions d'amplitude, de fréquence de pulsation variables. Par ailleurs, nous avons entrepris l'adaptation et la validation d'un logiciel d'analyse d'images pour la quantification de l'agrégation en termes de structure des rouleaux et agrégats. Le deuxième type d'action a été consacré à l'étude du rôle des produits de contraste ionique et non ioniques sur l'agrégation érythrocytaire, l'administration de ces produits pouvant entrainer des effets secondaire sévères: accidents thromboemboliques ou hémorragiques. Des approches complémentaires par des méthodes spectroscopiques au niveau microscopique et moléculaire ont permis de préciser le rôle des produits de contraste

A nefrotoxicidade induzida por contraste (NIC) é responsável por cerca de 11% de todas as causas de injúria renal aguda no ambiente hospitalar e tem sido atribuída exclusivamente aos contrastes iodados. Contudo, os contrastes à base de gadolínio recentemente estão sendo reportados como potenciais indutores de nefrotoxicidade em pacientes de alto risco. A fisiopatologia da NIC está relacionada à geração de hipóxia na medula renal vinculada à disfunção endotelial, e ao estresse oxidativo, alterações que têm sido fortemente associadas à deficiência de vitamina D (dVD), condição que encontra-se altamente prevalente na população atual, mesmo em países de clima tropical. O objetivo desse estudo foi testar a hipótese de que a dVD é um potencial fator de risco para NIC. Para isso, ratos Wistar foram mantidos em dieta padrão ou livre de vitamina D por 30 dias. A seguir, CI (diatrizoato 76%), Gd (gadoterato de meglumina) ou soro fisiológico 0,9% foram infundidos por via endovenosa. Seis grupos foram avaliados (n=12/grupo): Sham, CI, Gd, dVD30, dVD30+CI e dVD30+Gd. Após 48h da infusão dos contrastes, os animais foram submetidos ao experimento de clearance de Inulina, para estimar o ritmo de filtração glomerular (RFG), a análise da expressão proteica no tecido renal de angiotensinogênio (AGT), renina e da óxido nítrico sintase endotelial (eNOS), e ao exame histológico. O estado redox foi avaliado por meio da medida das espécies reativas ao ácido tiobarbitúrico (TBARS, marcador de peroxidação lipídica), e dos níveis de glutationa reduzida (GSH, antioxidante endógeno) sistêmico e renal. Comparado ao grupo Sham, os animais dVD30 apresentaram menores níveis séricos de 25(OH)D total (3,96±0,8 vs. 44,87±1,7 ng/mL, p < 0,001), níveis semelhantes de cálcio e fósforo plasmáticos e aumento da expressão renal de AGT e renina. O RFG foi similar nos grupos Sham, CI e Gd. Entretanto, o RFG foi significantemente menor nos grupos dVD30+CI e dVD30+Gd e esta redução esteve associada ao aumento no tecido renal da expressão de AGT e à redução da eNOS, combinado à acentuada elevação da razão TBARS/GSH no tecido renal. Apesar da alteração na função renal com a infusão dos contrastes, a morfologia renal permaneceu preservada. Foram feitos dois grupos adicionais (n=5/grupo) mantidos em dVD por 60 dias. Após administração dos contrastes, uma maior queda do RFG foi observada, sugerindo que uma dVD mais prolongada agrava ainda mais a queda do RFG. Coletivamente, nossos resultados indicam que a dVD é um potencial fator de risco para NIC iodado e de gadolínio em consequência do desequilíbrio intrarrenal de substâncias vasoativas por meio da ativação do sistema renina-angiotensina e do estresse oxidativo
Contrast-induced nephropathy (CIN) account for about 11% of all causes of acute kidney injury in hospitalized patients and has been attributed exclusively to iodinated contrast media. However, gadolinium-based contrast agents are reported recently as potential inducers of nephrotoxicity in high risk patients. Pathophysiology of CIN is related to hypoxia in the renal medulla associated with endothelial dysfunction and oxidative stress, changes that have been strongly linked to vitamin D deficiency (VDD), condition that is highly prevalent in the current population, even in tropical countries. This study tested the hypothesis that VDD is a predisposing factor for iodinated and gadolinium contrast media nephrotoxicity. To this end, male Wistar rats were fed standard or vitamin D-free diet for 30 days (VDD30). Then, IC (diatrizoate 76%), Gd (gadoterate meglumine) or saline were administered intravenously and six experimental groups were obtained: Sham, IC, Gd, VDD30, VDD30+IC and VDD30+Gd. Renal hemodynamics, redox status, histological and immunoblot analysis were evaluated 48h after contrast or vehicle infusion. Compared to Sham, VDD30 rats presented lower levels of total 25(OH)D (3.96 +- 0.8 vs. 44.87 ± 1.7 ng/mL, p < 0,001), similar plasma levels of calcium and phosphorus and higher renal renin and angiotensinogen expression. Inulin clearance-based estimated glomerular filtration rate (GFR) was not different among Sham, IC and Gd groups. However, GFR was significantly reduced in VDD30+IC and VDD30+Gd groups and this reduction was associated with higher renal angiotensinogen and lower eNOS abundance combined with higher kidney thiobarbituric acid reactive substances and lower glutathione levels. Conversely, worsening of renal function was not accompanied by abnormalities on kidney structure or increased infiltration of inflammatory cells. Rats on a VDD for 60 days displayed a greater fall in GFR after contrast administration, suggesting that the longer the period of VDD, the worst the impact of contrast media on renal function. Collectively, our findings suggest that VDD is a potential risk factor for contrast nephropathy due to imbalance in intrarenal vasoactive substances by renin-angiotensin system activation and oxidative stress

Although the watersheds of the Petite Cascapedia and Bonaventure Rivers, Gaspe Peninsula, have broadly similar geology and land use, their segment-scale river geomorphology is contrasted by subtle differences in valley characteristics that are a legacy of their individual geomorphic histories. These differences have consequences on the distribution of Atlantic salmon habitat such as boulder abundance (for parr rearing and overwintering habitats) and spawning substrate quality. Parr preference for boulder-rich river segments (1--5 km) was observed in the Bonaventure River. In the study systems redd distribution was sensitive to relatively small changes in the fines content of riffle substrate. River segments flowing through moderately narrow semi-alluvial valleys present better overall parr habitat (high boulder abundance) and better spawning substrate quality (percentage of sand) than wider valley sections. These differences are due to additional sources of coarse sediment, higher shear stresses, and lower bank erosion rates in such valleys.

Introdução: As massas cardíacas (MC) podem ser tumores, trombos ou pseudotumores. A avaliação da vascularização poderá ser uma ferramenta adicional para o seu diagnóstico diferencial. Neste estudo, demonstrou-se o valor diagnóstico da ecocardiografia com perfusão na caracterização das MC or meio de análises qualitativas e quantitativas de perfusão. Métodos: Estudo prospectivo que envolveu 107 pacientes, classificados em quatro grupos: 33 trombos, 23 tumores malignos (TM), 24 tumores benignos (TB) e 6 pseudotumores; 21 pacientes foram excluídos por não terem diagnóstico definitivo confirmado. A avaliação de perfusão foi realizada pela ecocardiografia com perfusão em tempo real, utilizando contraste à base de microbolhas. Em um grupo selecionado de pacientes (32), o estudo foi complementado com dipiridamol para avaliação da reserva de fluxo da massa. A análise foi feita qualitativa e quantitativamente por dois observadores independentes. Na análise qualitativa, os parâmetros foram: intensidade da perfusão (escore 0 a 3), velocidade do repreenchimento microvascular (escore 0 a 2), padrão de perfusão central ou periférico (escore 0 a 2) e presença de áreas de necrose (escore 0 e 1). Os dois parâmetros de quantificação das massas foram: volume de sangue microvascular (A) e fluxo microvascular regional, que é o produto da velocidade de fluxo () e volume (A). Resultados: Na análise qualitativa, o padrão mais frequente para o grupo trombos foi: sem perfusão (81,9%), sem velocidade de perfusão (81,9%) e sem área de necrose (93,4%); nos tumores, predominou perfusão discreta (62,3%), com velocidade lenta (64,2%) e áreas de necrose (30,2%). Na análise qualitativa, a variação intraobservador para escore de perfusão e de velocidade foi de 20%, para áreas de necrose de 25% e para padrão de perfusão foi de 45%. Na análise quantitativa, o grupo trombos apresentou valores de A e Ax significativamente menores quando comparados ao grupo de tumores: Trombos: A = 0,08 (0,01-0,22dB); Ax = 0,03 (0,010,14dB/s-1); TM: A = 2,78 (1,31-7,0dB); Ax = 2,0 (0,995,58dB/s-1); TB: A = 2,58 (1,24-4,55dB); Ax = 1,18 (0,453,4dB/s-1). Quando comparados apenas os grupos de tumores com o uso de dipiridamol, os TM apresentaram volume sanguíneo microvascular (A) maiores: A = 4,18 (2,14-7,93dB); Ax = 2,46 (1,424,59dB/s-1), TB: A = 2,69 (1,11-4,26dB); Ax = 1,55 (0,555,50dB/s-1). Na análise com a curva ROC, a área sob a curva = 0,95, no parâmetro volume sanguíneo microvascular (A) < 0,65dB na ecocardiografia de perfusão com e sem uso de dipiridamol foi preditor para trombo, bem como o parâmetro fluxo sanguíneo microvascular (Ax) < 0,30dB/s-1, (área sob a curva = 0,94). Para distinguir entre TM de TB, o parâmetro volume sanguíneo microvascular (A), com o uso de dipiridamol > 3,28dB foi preditor de TM (área sob a curva = 0,75). Conclusão: O estudo ecocardiográfico para avaliação da perfusão das MC mostrou que a análise qualitativa é um método diagnóstico rápido e reprodutível para diagnosticar trombos. Os tumores cardíacos apresentam volume microvascular e fluxo sanguíneo regional maior se comparados com os trombos. O uso do dipiridamol foi útil na diferenciação entre os TM e TB
Background: Cardiac masses (CM) can be tumors, thrombi or pseudotumors. Evaluation of their vascularization might be an additional tool to perform a differential diagnosis. In the present study we demonstrated the diagnostic value of perfusion echocardiography for CM characterization, by qualitative and quantitative analyses of perfusion. Methods: We prospectively studied 107 patients, who were classified into 4 groups: 33 thrombus, 23 malignant tumors (MT), 24 benign tumors (BT) and 6 pseudotumors, of which 21 were excluded because no definitive diagnosis could be confirmed. Perfusion evaluation was performed by contrast echocardiography with real time perfusion imaging using microbubbles. A group of patients (32) was selected for a complementary study using dipyridamole to evaluate mass flow reserve. Qualitative and quantitative analyses were performed by two independent observers. Parameters for qualitative analysis were perfusion intensity (0-3 score), microvascular refilling velocity (0-2 score), central or peripheral perfusion pattern (0-2 score), and presence of areas of necrosis (0 or 1 score). The two parameters for quantification of masses were microvascular blood volume (A), and regional microvascular flow which is the product of blood flow velocity and vomume (A). Results: The most frequent pattern for the thrombi group in the qualitative analysis was absence of perfusion (81.9%), followed by no perfusion velocity (81.9%), and no areas of necrosis (93.4%), whilst among tumors there was predominance of discrete perfusion (62.3%), with slowed velocity (64.2%), and areas of necrosis (30.2%). Qualitative analysis, perfusion velocity showed intraobserver variability 20%, presence of areas of necrosis of 25% and perfusion pattern of 45%. In the quantitative analysis, the thrombi group was shown to have A and Ax values significantly smaller compared to the tumor group: Thrombi: A = 0.08 (0.01-0.22dB); Ax = 0.03 (0.010.14dB/s-1); MT: A = 2.78 (1.31-7.0dB); Ax = 2.0 (0.995.58dB/s-1); BT: A = 2.58 (1.24-4.55dB); Ax = 1.18 (0.453.4dB/s-1). When only the tumor groups with the use of dipyridamole were compared, MT was shown to have greater microvascular blood volume (A): A = 4.18 (2.14-7.93dB); Ax = 2.46(1.424.59dB/s-1), BT: A = 2.69 (1.11-4.265dB); Ax = 1.55 (0.555.50dB/s-1). Analysis of the ROC curve showed that an area of 0.95 for a microvascular blood volume of A < 0.65 dB predictive curve on perfusion echocardiography, both with and without dipyridamole, predicts thrombi, and so does a <0.30dB/s-1microvascular blood flow (Ax), area under curve = 0.94. In order to distinguish MT from BT, a >3.28dB microvascular blood volume (A) using dipyridamole was predictor of MT (area under curve = 0.75). Conclusion: The echocardiographic study to evaluate CM perfusion showed that qualitative analysis is reproducible diagnostic approach for diagnosing thrombi. Cardiac tumors show greater microvascular volume and regional blood flow when compared with thrombi. Dipyridamole quantitative stress mass perfusion was useful to differentiate MT from BT

This thesis explores the variable behavior of bare nouns in Persian. Bare singular nouns realize different grammatical functions, including subject, object and indirect object. They receive different interpretations, including generic, definite and existential readings. However, the task of understanding the reasons for, and limits on, this variation cannot be achieved without understanding a number of pivotal features of Persian sentential architecture, including Information Structure, prosody, word order, and the functions of various morphological markers in Persian. After a brief introduction, chapters 2-3 deal with bare noun objects, firstly comparing them with nominals marked with indefinite morpheme -i suffixed to the noun, and the determiner yek. A bare noun object differs from morphologically marked nominals as it shows properties associated with noun incorporation in the literature (chapter 2). Of particular interest are the discourse properties of these ‘quasi-incorporated’ nominals. With respect to the discourse transparency of Incorporated Nominals, Persian belongs to the class of discourse opaque languages within Mithun’s classification (1984). However, under certain circumstances, Persian bare nouns show discourse transparency. These circumstances are examined in chapter 3, and it is proposed that bare nouns do introduce a number neutral discourse referent. There are no overt anaphoric expressions that could match such number-neutral antecedents in Persian. But covert anaphora lack number features, and hence can serve as means to pick up a number-neutral discourse referent. Also, in case world knowledge tells us that the number-neutral discourse referent is anchored to an atomic entity or to a collection, then an overt singular pronoun or an overt plural pronoun might fit the combined linguistic and conceptual requirements, and may be used to pick up the number-neutral discourse referent. This proposal is phrased within Discourse Representation Theory. In the second half of the dissertation, the interpretation of bare nouns in different positions and with different grammatical functions are discussed. Under the independently supported hypothesis of position>interpretation mapping developed by Diesing (1992), we will see the role of the suffix -ra in indicating that an object has been moved out of VP. Following Diesing, I assume that VP-internal variables are subject to an operation of Existential Closure. In many cases, VP-external –ra-marked objects have a different interpretation to their VP-internal, non-ra-marked, counterparts, because of escaping Existential Closure. For subjects, there is no morphological marking corresponding to –ra on objects, and we have to rely on prosody and word order to determine how a VP is interpreted using theories of the interaction of accent and syntactic structure. We assume that VP-internal subjects exist, under two independent but converging assumptions. The first is prosodic in nature: Subjects can be accented without being narrowly focused; theories of Persian prosody predict then that there is a maximal constituent that contains both the subject and the verb as its head. The second is semantic in nature: Bare nouns require an external existential closure operation to be interpreted existentially, and we have to assume existential closure over the VP for our analysis of the interpretation of objects. So, this existential closure would provide the necessary quantificational force for bare noun subjects as well. It is proposed that both subject and object originate within the VP, and can move out to the VP-external domain. The motivation for these movements are informational-structural in nature, relating in particular to the distinctions between given and new information, and default and non-default information structure.

碩士
大葉大學
應用外語研究所
98
The purpose of the study is to investigate EFL learners’ use of contrastive stress scaffolded with an Automatic Speech Analysis System (ASAS). Three independent variables: training methods, students’ English proficiency and contrastive stress types, were explored as the function on use of contrastive stress. Participants were 43 English-majored freshmen at a university in central Taiwan. They were selected from three English conversation classes. Based on English conversation scores, 22 of them were categorized as high-proficient and 21 were low-proficient students. The training lasted for six weeks and every two weeks covered one type of contrastive stress. A pretest and a posttest were done before and after the training of each contrastive stress type. Three training methods were implemented: the teacher’s lecture and practice with the ASAS, practice with the ASAS, and the teacher’s lecture and practice with printed handouts. Three types of contrastive stress were involved: double objects, single object, and incomplete double objects. Two-way ANCOVA, two-way ANOVA, paired-sample t-test and simple main effect analysis were conducted to analyze students’ use of contrastive stress from two perspectives: pronunciation and pitch. The Goodness of Fit test was used to examine students’ perception toward the ASAS. The main findings are described as follows: 1. The ASAS has the potential to help EFL learners achieve more native-like speech with regards of pronunciation in sentences exhibiting contrastive stress. 2. Different types of contrastive stress pose different levels of difficulty for adult EFL learners.. 3. High-proficient students made more improvement than low-proficient students on the use of contrastive stress through practice with an ASAS, but both of them need the teacher’s lecture on pitch learning. 4. Students hold positive attitudes toward the ASAS and would like to recommend it to other learners. The results of data analysis indicate that the ASAS is beneficial to students’ motivation and oral skills. However, the teacher’s lecture is essential to students’ learning of contrastive stress, especially when the contrastive stress gets more difficult or tricky and involves higher-order cognitive knowledge. It is suggested that in addition to the teacher’s instruction students could practice their use of contrastive stress with an ASAS to bring about more promising learning outcomes.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1992.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 244-248).

碩士
大葉大學
應用外語研究所
95
The study aimed to explore the impact of Automatic Speech Recognition System (ASRS) on the development of English oral abilities including pronunciation, pitch, timing and emphasis for EFL college students in Taiwan. It is used ASRS—MyET to increase students’ opportunities of after-class oral practice and training in virtual learning communities. The participants were 40 freshmen at the English Department of DaYeh University in Taiwan. They were assigned into a control group and an experiment group. Each group contains 20 students, including 10 English low-proficient and 10 English high-proficient students according to their English scores of the pretest. The control group received the lecture on contrastive stress in a classroom. In addition to the lecture in a classroom as the control group, the experiment group was required after the class to practice contrastive stress with an ASRS for six weeks. After six-week treatment, all participants did a posttest. The main findings are: (1) The ASRS helps students improve their pronunciation, pitch and timing. (2) The ASRS helps low-proficient students improve their pronunciation, pitch and timing more than high-proficient students. (3) Most students held positive attitudes toward the use of ASRS. Based on the findings, some discussion of the results, pedagogical implications and suggestions for further study are proposed.

Thesis (M.A.)--York University, 2008. Graduate Programme in Psychology.
Typescript. Includes bibliographical references (leaves 37-42). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51526

Tese de mestrado. Biologia (Biologia Evolutiva e do Desenvolvimento). Universidade de Lisboa, Faculdade de Ciências, 2012
Rice is one of the foremost crops in the history of humanity and today it feeds billions of people worldwide, as it is the second most cultivated crop. However, rice can be affected by various environmental stresses. Global climatic models predict a gradual increase in temperature by an average of 2-4ºC by the end of this century (IPCC, 2007). Thus, future climates with increased magnitude and frequency of heat waves pose a real threat to sustained rice production with an obvious implication on increasing rice prices. Little is known regarding the impact of abiotic stress on epigenetic marks in the genome. The main goal of the thesis is to understand in what extent heat stress can modulate DNA methylation from a global level to a gene specific point of view. The use of contrasting rice varieties, non-tolerant (Nipponbare) and tolerant (N22) to heat stress, allowed approaching the meaning of DNA methylation in heat stress tolerance. The heat tolerant rice variety N22 showed higher global DNA methylation level when compared with the heat sensitive variety cv. Nipponbare. Furthermore, the heat stress imposition caused a decrease in DNA methylation being that particularly notorious in the tolerant variety. This suggests that the tolerant variety may possess more efficient responsive mechanisms to modulate DNA methylation at global level under heat stress. Additionally, induced DNA hypomethylation was associated to increased expression of DNA demethylases suggesting an involvement of active mechanism to modulate DNA methylation. The heat shock response pathway targets showed an increased expression under heat stress being that particularly evident in the heat sensitive variety suggesting its need to faster trigger specifically heat stress related genes. The heat tolerant plants may have more complex and intricate mechanisms justifying its tolerance and thus, would not need to rely so much in regulating the expression of specific genes but instead could account with genome wide regulatory mechanisms (e.g. involving physical interactions with heterochromatic regions). The plasticity of methylation pattern at specific gene after heat stress revealed a minor increase in DNA methylation at the promoter region while in the coding region was detected a methylation shift to CG sites that should compatible with increased gene expression under heat stress. The knowledge gathered with this work may contribute to better understand how rice can cope with adverse temperatures raising the relevance of DNA methylation for heat stress tolerance.
O arroz (Oryza sativa) é uma das plantas de cultivo com maior importância na história da humanidade, tendo sido uma das primeiras a ser domesticadas, e agora ocupa um nicho essencial na nutrição humana, sendo a segunda planta mais cultivada no mundo, a seguir ao milho, e a que tem maior impacto na alimentação da população humana na escala global, sendo a fonte primária de nutrição para cerca de 70% da população mundial. O arroz assume uma grande importância também a nível nacional, sendo Portugal o maior consumidor europeu de arroz per capita, com uma produção insuficiente para suprir as sua próprias necessidades. Alterações climáticas como a temperatura e a humidade, podem ter um efeito adverso na fisiologia dos seres vivos expostos a estas mudanças, gerando stresses abióticos. As respostas ao stress têm consequências para a viabilidade dos organismos afectados, podendo por em risco a sua capacidade de sobrevivência e o seu sucesso reprodutivo. O arroz é vulnerável a vários destes stresses abióticos, especialmente ao stress de frio, secura, salinidade e de calor. A exposição a stresses abióticos pode comprometer a capacidade reprodutiva do arroz, e consequentemente a produção de sementes com impacto crucial na produção mundial de alimentos. Todos os seres vivos possuem mecanismos de resposta ao stress para diminuir o seu impacto negativo, e estes diferem entre reinos. As plantas, sendo organismos sésseis, não podem evitar a exposição ao stress e são forçadas a suportar o seu efeito. Assim, foram forçadas a desenvolver mecanismos complexos de resposta ao stress. Para o stress de calor, existe uma rede complexa de sinalizadores e proteínas, da qual fazem parte as famílias de Heat shock factors (OsHsf) e Heat shock proteins (OsHsp). Estes genes e pathways são regulados por vários mecanismos, incluindo mecanismos epigenéticos. A epigenética engloba todos os processos de regulação da actividade de transcrição do DNA que são mitótica e meioticamente herdados, mas que não envolvem alterações na sequência do DNA. Existem vários meios de regulação epigenética de transcrição, como sRNAs, factores de transcrição, mudanças pós-transcripcionais de mRNA, e alterações na estrutura conformacional da cromatina. A plasticidade da organização da cromatina pode envolver alterações entre um estado mais descondensado (eucromatina) e compactado (heterocromatina). Esta condensação da cromatina tem um efeito sobre o acesso das DNA transcriptases e outras proteínas à cadeia de DNA, podendo assim regular a transcrição de genes. A condensação da cromatina é regulada por modificações epigenéticas sobre os seus constituintes, as histonas e a própria cadeia de DNA. A cadeia de DNA também pode ser modificada por vários processos sendo a metilação das citosinas a modicação mais extensivamente estudada com relevância da regulação da transcrição de genes. A 5-metilcitosina (5mC) é o primeiro marcador de um processo que leva a heterocromatinização impedindo a transcrição. A metilação do DNA é encontrada mais frequentemente ao nível de regiões repetitivas do genoma, como por exemplo, centrómeros e telómeros, e também ao nível de transposões. Contudo, tem-se encontrado evidência que a metilação do DNA pode ocorrer ao nível regiões codificantes de genes. A metilação do DNA é estabelecida por DNA metiltransferases, como MET1, DRM e CMT, que ligam os grupos metilo ao anel do nucleótido da citosina. Estas enzimas dependem do contexto da própria sequência para reconhecer sítios potencialmente metiláveis. Em plantas existem três tipos de contextos de metilação onde estas enzimas se podem ligar, nomeadamente, CG, CHG e CHH. Cada contexto é metilado por uma enzima específica, e estas enzimas, nomeadamente metiltransferases, asseguram que a metilação permanece após processos de divisão celular. Uma falta de renovação da metilação seria um processo passivo de demetilação do DNA, mas em plantas há provas da existência de mecanismos activos de demetilação. DNA glycosilases como ROS1, DME, DLP2 e DLP3 são capazes de excisar 5mC da cadeia. Também se tem descoberto que a distribuição da metilação pelo DNA seguem um padrão “site-specific”, com a metilação CG sendo mais comum em áreas activas do cromossoma. Tudo isto providencia provas que a metilação do DNA é um mecanismo activo de regulação da transcrição, e é possível que esteja envolvida na regulação da resposta a stresses ambientais. O objectivo deste trabalho consistiu em perceber em que medida a metilação do DNA pode ser alterada na resposta ao stress de calor em arroz e qual o papel que poderá ter na tolerância ao stress. Neste estudo foram utilizadas duas variedades distintas de arroz com diferentes graus de resistência ao stress de calor. Para uma variedade sensível, utilizámos a variedade Nipponbare (O. sativa ssp japonica), e para uma variedade tolerante, recorremos a N22 (O. sativa ssp indica). Para alcançar o primeiro objectivo, estudámos a metilação do DNA ao nível global através de duas técnicas nomeadamente, a imunodetecção com um anticorpo para a 5-metilcitosina de locais de metilação em núcleo interfásicos de secções de tecido da raíz de arroz e a quantificação relativa de metilação global por um método de ELISA essencialmente baseado no uso de anticorpos sensíveis à 5mC. Os resultados sugerem que a metilação do DNA é afectada por stress de calor, sofrendo uma redução, mas que esta resposta requer tempo além do inicio da exposição ao stress, demorando um período que se pode estender até 24 horas. Também foram obtidos indícios da metilação do DNA estar potencialmente envolvido na tolerância ao stress, na medida em que a variedade N22 apresentou uma maior metilação relativamente à variedade Nipponbare. Estudos sobre um número de DNA glicosilases com potencial actividade de desmetilação do DNA mostraram que estas são pouco afectadas pelo stress de calor quando este é imposto por um curto período de tempo (2 H). Contudo, estudos de expressão destas demetilases após hipometilação induzida do DNA, através do uso da droga 5-azacitidina, demonstraram uma forte expressão, especialmente nos genes que codificam para as DNG701 e DNG702, sendo que o primeiro já tinha sido descrito em arroz como tendo actividade de desmetilação do DNA. Para estudar o efeito da metilação do DNA sobre a resposta ao calor, realizámos um estudo de expressão sobre elementos das famílias OsHsf e OsHsp20, pertencentes à pathway de resposta ao stress de calor, sob tratamentos de stress de calor de curta duração e de hipometilação induzida via exposição à droga 5-metilcitosina. Os dois genes candidatos da família OsHsp20 sofreram uma indução de expressão sob stress de calor em ambas as variedades, sendo contudo de notar que a indução foi mais drástica na variedade Nipponbare que na N22. Um destes dois genes, OsHsp20-18, também teve uma indução de expressão no tratamento de hipometilação induzida, pelo que foi alvo de um estudo aprofundado dos seus padrões de metilação do DNA através do uso de sequenciação pelo método de bisulfito. Esta técnica permite resolver os padrões de metilação até aos sites individuais, incluindo o contexto de metilação. Os resultados demonstraram que o promotor e a região codificante do gene possuem padrões distintos sob condições controlo, e que também diferem no seu comportamento sob stress de calor, sendo que o promotor sofre um aumento da metilação total, enquanto que ao nível da região codificante há uma troca entre diferentes contextos de metilação mantendo-se no entanto a percentagem total da metilação do DNA. O conhecimento gerado com este trabalho poderá contribuir para uma melhor compreensão do modo como o arroz poderá lidar com condições sub óptimas para o seu crescimento levantando questões relevantes sobre o papel da metilação do DNA na tolerância ao stress de calor.

No
This study compares associations between demographic profiles, long bone lengths, bone mineral content, and frequencies of stress indicators in the preadult populations of two medieval skeletal assemblages from Denmark. One is from a leprosarium, and thus probably represents a disadvantaged group (Næstved). The other comes from a normal, and in comparison rather privileged, medieval community (Æbelholt). Previous studies of the adult population indicated differences between the two skeletal collections with regard to mortality, dental size, and metabolic and specific infectious disease. The two samples were analyzed against the view known as the osteological paradox (Wood et al. [1992] Curr. Anthropol. 33:343-370), according to which skeletons displaying pathological modification are likely to represent the healthier individuals of a population, whereas those without lesions would have died without acquiring modifications as a result of a depressed immune response. Results reveal that older age groups among the preadults from Næstved are shorter and have less bone mineral content than their peers from Æbelholt. On average, the Næstved children have a higher prevalence of stress indicators, and in some cases display skeletal signs of leprosy. This is likely a result of the combination of compromised health and social disadvantage, thus supporting a more traditional interpretation. The study provides insights into the health of children from two different biocultural settings of medieval Danish society and illustrates the importance of comparing samples of single age groups.

The aims of this thesis were to characterize the molecular ecology of the hyporheic zone – between dissolved organic matter (DOM) and microbes – and to test whether seasonal and spatial patterns existed in correlation with seasonal ecosystem processes. The hyporheic zone is an area of vertical integration between groundwater and surface water, and lateral integration between terrestrial and stream ecosystems. Colonization corers were used to collect in situ DOM and bacterial communities from the hyporheic sediments of two streams that varied in hydroperiod (i.e., permanent vs. intermittent). DOM was collected using passive samplers and analyzed using 1H NMR and fluorescence spectroscopy; bacteria were characterized using terminal-restriction fragment length polymorphism. At the permanent site, bacteria correlated significantly with seasonal environmental factors including: fall communities with DOM concentration; spring and winter communities with nitrate concentrations; and summer communities with temperature. Bacterial communities at the intermittent site were significantly correlated with flooding as a function of hydrologic connectivity. Sediment communities were discriminated between hyporheic sediments and interstitial porewaters, and shared several operational taxonomic units (OTUs). Sediment communities were more distinct when hydrologic connectivity was low, and porewater communities changed dramatically upon flooding. Fifteen out of 259 OTUs were shared across aquatic sediments, interstitial porewater and watershed soil samples. DOM was spatially and seasonally dynamic in both sites. Five key DOM groups described using 1H NMR spectroscopy revealed spatial differences between the permanent and intermittent sites. EEM-PARAFAC models confirmed that despite significantly different molecular components, the relative sources of DOM at both sites were similar, including humic-like terrestrial sources and tyrosine (microbial) sources. This study provides new knowledge on both organic matter dynamics and bacterial communities in a dynamic aquatic ecotone, and also confirmed the hypothesis that bacterial communities correlated significantly with ecosystem processes within a watershed.