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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Further Evaluating the Effect of Behavioral Observability and Overall Impressions on Rater Agreement: A Replication Study

Sizemore, Patrick 01 May 2015 (has links)
This replication study sought to analyze the effects of behavioral observability and overall impressions on rater agreement, as recently examined by Roch, Paquin, & Littlejohn (2009) and Scott (2012). Results from the study performed by Roch et al. indicated that raters are more likely to agree when items are either more difficult to rate or less observable. In the replication study conducted by Scott, the results did not support the relationship which Roch et al. found between observability and rater agreement, but did support the relationship previously found between item difficulty and rater agreement. The four objectives of this replication study were to determine whether rater agreement is negatively related to item observability (Hypothesis 1) and positively related to difficulty (Hypothesis 2), as well as to determine whether item performance ratings are closer to overall impressions when items are less observable (Hypothesis 3) and more difficult to rate (Hypothesis 4). The sample was comprised of 152 undergraduate students tasked with providing performance ratings on an individual depicted in a video of a discussion group. Results indicated that agreement was negatively correlated with both observability (supporting Hypothesis 1) and difficulty (not supporting Hypothesis 2), and that ratings were closer to overall impressions when items were less observable (supporting Hypothesis 3), but not when items were more difficult to rate (not supporting Hypothesis 4).
92

The Effects of Anticipated Feedback Proximity on Performance: Exploring the Moderating Role of Self-Efficacy and Task Type

Xu, Xingya 01 May 2015 (has links)
The present study investigated the effect of anticipated feedback proximity (immediately after completing the task or one week later) on performance and the moderating role of self-efficacy and task types (analytical or creative). I hypothesized that expecting rapid feedback should yield better performance than expecting delayed feedback, for people with high self-efficacy or those who receive analytical tasks. For those who receive creative tasks or have low self-efficacy, expecting rapid feedback may produce negative impact on performance. The results indicated a trend of main effect of anticipated feedback proximity. Specifically, participants performed better when they expected immediate feedback relative to expecting delayed feedback, regardless of the task type. There was also a main effect of task type. Performance on the analytical tasks was better than performance on the creative tasks. However, neither self-efficacy nor task type moderated the effects of anticipated feedback proximity. The implications for these findings are discussed herein.
93

Age Differences in the Impact of Emotional Cues on Subsequent Target Detection

Coffey, Brandon Wade 01 July 2015 (has links)
Emotional cues within the environment capture our attention and influence how we perceive our surroundings. Past research has shown that emotional cues presented before the detection of a perceptual gap can actually impair the perception of elementary visual features (e.g., the lack of detail creating a spatial gap) while simultaneously improving the perception of fast temporal features of vision (e.g., the rapid onset, offset, and re-emergence of a stimulus). This effect has been attributed to amygdalar enhancements of visual inputs conveying emotional features along magnocellular channels. The current study compared participants’ ability to detect spatial and temporal gaps in simple stimuli (a Landolt Circle) after first being exposed to a facial cue in the periphery. The study was an attempt to replicate past research using younger adult samples while also extending these findings to an older adult sample. Unlike younger adults, older adults generally display an attentional bias toward positive instead of negative emotional facial expressions. It is not clear if this positivity bias is strictly driven by cognitive control processes or if there is a change in the human visual system with age that reduces the amplification of negative emotive expressions by the amygdala. The current study used psychophysical data to determine if the rapid presentation of an emotional cue and subsequent perceptual target to older adults leads to the same benefit to temporal vision evinced by younger adults or if amygdalocortical enhancements to perception degrade with age. The current study was only able to partly replicate findings from past research. The negative facial cues that were presented in the periphery did not lead to an enhancement in temporal gap detection for the younger adult sample nor a reduction in spatial gap detection. In fact, the opposite was found. Younger adults’ spatial gap detection benefited from the negative emotional cues. The negative and neutral emotional cues had no effect on the older adult sample. The older adults’ performance on both gap detection tasks was not impacted by the emotional cues
94

Self-Regulation in Preschoolers: Validity of Hot and Cool Tasks as Predictive Measures of Academic and Socio-Emotional Aspects of School Readiness

Anaya, Berenice 01 July 2016 (has links)
Extensive research on the development of self-regulation has demonstrated that better executive functioning and effortful control during the preschool years are associated with greater kindergarten and early school achievement. Recent findings suggest that self-regulation tasks differ in their assessment of “hot” and “cool” regulation, how these processes map onto effortful control and executive functioning, and may predict school readiness. However, only a few studies have examined the validity of hot and cool regulation tasks (Allan & Lonigan, 2014; Di Norcia, Pecora, Bombi, Baumgartner, & Laghi, 2015; Willoughby, Kupersmidt, Voegler-Lee, & Bryant, 2011), and how they predict socio-emotional competence (Di Norcia et al., 2015) and academic performance (Kim, Nordling, Yoon, Boldt, & Kochanska, 2013). The current study examined the validity of hot and cool tasks as measures of self-regulation and predictive measures of school readiness within a low-income sample. The sample consisted of 64 preschoolers between the ages of three (n= 38) and four (n= 26) who were enrolled in a blended Head Start program. The Preschooler Self-Regulation Assessment, Woodcock Johnson subtests (Letter Word, Applied Problem, and Picture Vocabulary), and teacher ratings of social competence (Social Competence and Behavioral Evaluation) and emotional competence (Emotion Regulation Checklist) were collected in the fall and spring of the school year. Results indicated that performance on the Cool and Hot tasks was moderate to highly correlated with academic performance and teacher ratings of socio-emotional competence respectively. Developmental differences in selfregulation performance suggested that cool regulation begins to develop later in the preschool period and may depend on earlier development of hot regulatory processes. There were also gains in academic achievement and socio-emotional competence from fall to spring. Regression analyses indicated that Hot and Cool tasks did not predict socio-emotional competence and academic achievement as distinctively as expected. Hot and cool regulation seemed to predict socio-emotional competence and academic achievement in parallel, with the exception of math performance, which was strongly predicted by Cool task performance above and beyond Hot tasks. Results suggest that hot and cool regulation overlap in predicting school readiness.
95

Investigation of the Responsive and Initiative Dimensions in the Client-Therapist Relationship in Gestalt and Behavior Therapy

Pierce, Lynda M 01 January 1977 (has links)
Research findings to the present have indicated the responsive and initiative dimensions to be important in the therapeutic process in influencing positive outcome; yet, investigators of current therapeutic approaches have not discussed how these dimensions might be integrated into their particular orientation. Therefore, a review of the literature investigating emphasis on the responsive and initiative dimensions in the major theoretical approaches seems warranted. This procedure involves superimposing Carkhuff’s theoretical model, developed for facilitation of therapeutic outcome, upon certain of the therapeutic approaches.
96

Learning Related Regulation of a Voltage-Gated Ion Channel in the Cerebellum

Fuchs, Jason R. 01 January 2016 (has links)
The neural mechanisms that support learning and memory are still poorly understood. Much work has focused on changes in neurotransmitter receptor expression, while changes in voltage-gated ion channel expression have been largely unexplored, despite the fact that voltage-gated ion channels govern neuronal excitability. Here we used eyeblink conditioning (EBC) in rats, a model of learning and memory with a well-understood neural circuit, to examine regulation of voltage-gated ion channels as a consequence of learning. EBC is a form of classical conditioning that involves pairings of a behaviorally neutral conditioned stimulus (CS) and an eyeblink eliciting unconditioned stimulus (US) over many trials to produce an eyeblink conditioned response (CR) to the CS in anticipation of the US. The acquisition and generation of the eyeblink CR is governed by plasticity at various sites in the cerebellum, both in the cerebellar cortex and the interpositus nucleus (IPN). Purkinje cells (PCs) are the primary neuron in the cerebellar cortex and these cells represent the sole output of the cerebellar cortex. PCs tonically inhibit the neurons of the IPN; the IPN is the start of the eyeblink pathway. In order for a CR to be generated, the inhibition of the IPN by PCs must be lifted. Basket cells (BCs) are small inhibitory interneurons that form synapses near the PC soma. These neurons are strategically located to strongly regulate PC output through inhibitory input near the axon hillock. BC axon terminals have the highest expression of Kv1.2, an alpha subunit of the Kv1 (Shaker) family of voltage-gated potassium channels, in the cerebellum. In addition, significant Kv1.2 expression is found on PC dendrites. Blocking Kv1.2 leads to increased GABAergic input to PCs and facilitates EBC. In the current work, we addressed the question of whether EBC itself regulates surface expression of Kv1.2 in cerebellar cortex. Rats received three days of either EBC, explicitly unpaired stimulus presentations, or no stimuli, and cerebellar tissue was harvested and analyzed via biotinylation/western blot (WB) and multiphoton microscopy (MP) techniques. In the first experiment, the Unpaired group showed significantly reduced surface Kv1.2 expression at BC axon terminals as measured by MP, but no changes observed with the WB measure, which measures expression at both BC axon terminals and PC dendrites. The second experiment used the same procedures but examined cerebellar tissue following a shorter training procedure. We hypothesized that the Paired and Unpaired groups would show similar Kv1.2 surface expression earlier in training. The Unpaired group showed increased surface Kv1.2 compared to the other two groups in the WB measures, but no differences were observed in the MP measure. Paired group rats that did not exhibit CRs showed the same pattern as the Unpaired group. Overall, we observed training and location specific changes in surface Kv1.2 expression, suggesting that learning does appear to regulate voltage-gated ion channel expression in the mammalian brain. Increased surface Kv1.2 early in training before CR expression emerges may set the stage for other mechanisms to govern the expression of the learned response. Prolonged stimulus input that is unmodulated by expression of a learned response, such as in the Unpaired group in the first experiment, leads to long-term changes in surface Kv1.2 expression exclusively at BC axon terminals.
97

The Effects of Self-Threats and Affirmations on Romantic Relationship Functioning: The Moderating Roles of Self-Esteem and Relationship-Contingent Self-Esteem

Zangl, Jennifer Lynn 01 January 2016 (has links)
Although romantic relationships are an important source of self-esteem, individuals vary in the degree to which romantic relationships determine their self-esteem. For individuals with relationship-contingent self-esteem (RCSE), self-esteem is based on the quality of perceived romantic relationship functioning. In contrast, global self-esteem is derived from a variety of domains, not specifically relationship quality. The present study investigated the moderating effects of RCSE and global self-esteem on the effects of relationship specific or relationship-unrelated threats and self-affirmations. Individuals with low global self-esteem react to threats by distancing themselves from their romantic partners. For those low in RCSE, this should occur only when the threats are relationship specific, whereas those low in global self-esteem distance themselves regardless of what type of threat they experience. Exposure to self-affirmations limits this defensive distancing in individuals with low global self-esteem. Prior studies examining the effects of induced self-threats and self-affirmations on perceived relationship functioning have been limited by reliance on college student samples, whose relationships are often shorter in duration than older adults. The current studies examined self-esteem and RCSE within the context of older participants in longer romantic relationships. Specifically, Study 1 examined how self-threats and self-affirmations interacted with dispositional levels of RCSE and self-esteem to predict romantic relationship outcomes. Participants wrote about past experiences to induce self-affirmations or self-threats, which were either relational (i.e., about their current relationship) or non-relational (i.e., about their personal lives), and then completed measures of relationship functioning. Contrary to predictions, there were no significant interactions between either RCSE or self-esteem and the experimental conditions. There was a significant main effect for self-esteem, such that participants with low self-esteem reported less commitment, closeness, and satisfaction as compared to participants with high self-esteem. In Study 2, participants completed one of two writing prompts: a prompt to induce high RCSE, or a control prompt. Participants then wrote about past experiences to induce self-threats that were either relational or non-relational. Contrary to hypotheses, inducing high levels of RCSE and exposing participants to a relational self-threat did not result in decreased relationship commitment, closeness, or satisfaction. The results of both Study 1 and Study 2 are contrary to previous research; potential explanations for this discrepancy and implications are discussed.
98

Electronic Cigarette User Plasma Nicotine Concentration and Puff Topography: Influence of Liquid Nicotine Concentration and User Experience

Hiler, Marzena M 01 January 2016 (has links)
Electronic cigarettes (ECIGs) aerosolize an often nicotine-containing solution for user inhalation. ECIG nicotine delivery may depend on liquid nicotine concentration and user puffing behavior (topography). This study examined the relationship among liquid nicotine concentration, puff topography, and plasma nicotine concentration. Thirty-three ECIG-experienced and 31 ECIG-naïve individuals completed four laboratory sessions that differed by ECIG liquid nicotine concentration (0, 8, 18, or 36 mg/ml). A 3.3 volt “eGo” ECIG battery attached to a 1.5 Ohm dual coil “cartomizer” filled with 1 ml of 70% propylene glycol/30% vegetable glycerin nicotine liquid was used in two ECIG-bouts (10 puffs; 30 s IPI). Plasma nicotine concentration, puff topography, and HR were evaluated. Some ECIG/liquid combinations can deliver physiologically active doses of nicotine to users, and nicotine delivery depends on liquid nicotine concentration and user puffing behavior. Liquid contents, device characteristics, and user behavior should be considered when regulating ECIGs.
99

Análise teórica e experimental do comportamento ao cisalhamento de vigas em alvenaria estrutural de blocos de concreto / Numerical and experimental analysis of the shear behaviour of concrete block masonry beams

Moraes, Rafael Santos de 19 December 2017 (has links)
O comportamento mecânico de vigas em alvenaria estrutural submetidas ao cisalhamento é abordado de forma aprofundada neste trabalho. São apresentados neste estudo um extensivo levantamento bibliográfico, o qual estabelece um panorama sobre o tema, um programa experimental com ensaios de caracterização do material alvenaria e de vigas em escala natural e um estudo numérico das vigas ensaiadas em laboratório. Na etapa de caracterização dos materiais o comportamento compósito da alvenaria é analisado por meio de prismas submetidos à compressão em duas direções ortogonais, normal e paralela à junta. Para o estudo das vigas são realizados trinta e sete ensaios, nos quais são avaliadas as influências da geometria, das taxas de armaduras e da relação a/d (em que a é a distância da carga aplicada até o apoio e d é a altura útil) na capacidade resistente ao cisalhamento. Posteriormente, é realizada a modelagem numérica através do software DIANA® com o propósito de complementar as análises dos ensaios. A partir dos resultados experimentais e numéricos pôde-se concluir que, com exceção das vigas com armaduras longitudinais de 10 mm de diâmetro, os demais modelos atingiram a ruína por cisalhamento, devido à ausência de estribos ou pela sua insuficiência. O aumento da taxa de armadura longitudinal de 0,45 para 1,18% resultou em um incremento de 18,4% na resistência ao cisalhamento convencional. Para as duas geometrias (vigas com duas e três fiadas) e as duas relações a/d (0,77 e 1,72), constatou-se que não há uma melhora significativa na capacidade resistente quando a taxa de armadura transversal é aumentada de 0,05 para 0,07%. Os mecanismos resistentes, como o efeito de pino, foram efetivos na resistência dos modelos. Por fim, as análises numéricas reproduziram de forma satisfatória os experimentos, tanto no que diz respeito ao comportamento pré e pós-pico quanto na previsão da força última. / This work is an in depth study about the mechanical behaviour of masonry beams subjected to shear forces. An extensive literature review, which establishes a panorama on the subject, an experimental program considering material characterization and full scale beams tests and a numerical study for the tested beams are presented. For the beams, thirty seven tests are carried out in which the influence of geometry, reinforcements ratio and a/d ratio (where a is the distance from the load to adjacent support and d is the effective depth) on the shear strength are evaluated. Computational modelling is performed using the DIANA® software in order to complement the experimental results. From the experimental and numerical results it was possible to conclude that, except for beams with 10 mm diameter steel bar, the other models failed in shear, due to the absence of stirrups or their insufficiency. An increase in longitudinal reinforcement ratio from 0,45 to 1,18% improved the theoretical shear strength in 18,4%. For the beams with two and three courses and for a/d ratios 0,77 and 1,72 it was found that there is no significant improvement on the load capacity when the transverse reinforcement ratio is increased from 0,05 to 0,07%. Shear strength mechanisms, such as the dowel action, were effective in the models load capacity. Finally, the numerical analyzes satisfactorily reproduced the experiments, regarding to the pre and post-peak behaviour and in the prediction of the ultimate load.
100

[en] DETERMINATION OF TRANSPORT COEFFICIENTS OF A PINNED ANNULAR HEAT EXCHANGER / [pt] DETERMINAÇÃO DOS COEFICIENTES DE TRANSPORTE EM UM TROCADOR DE CALOR BI-TUBULAR PINADO

ANGELA OURIVIO NIECKELE 27 August 2012 (has links)
[pt] Os coeficientes de troca e perda de carga de trocadores de calor do tipo bi-tubular pinado foram experimentalmente determinados. Medidas do coeficiente global de troca de calor do permitiriam avaliar o coeficiente de troca do lado do ar como função do número de Reyonolds do escoamento. Os resultados foram comparados com aqueles para trocadores de calor de duto anular, sem pinos, e a comparação revelou uma grande vantagem em relação à troca de calor para os trocadores pinados. Por outro lado, a comparação mostrou sua queda de pressão é consideravelmente mais alta. Não obstante, para a mesma taxa de transferência de calor, o trocador de calor pinado seria muito mais compacto. / [en] Experiments have been performed to determine the heat transfer characteristics and pressure drop of a pinned double-pipe heat exchangers. Measurements of the overall heat transfer coefficient as function of the air-side transfer coefficients as function of the flow Reynolds number. The results were compared with those for annular duct heat exchangers, without pins, and the comparison revealed a great advantage respect to the heat transfer for the pinned exchanger. On the other hand, the comparison showed that its pressure drop is considerably higher. Nevertheless, for the same heat transfer rate, the pinned exchanger would be much more compact.

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