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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.
21

Word-Recognition Performance in Interrupted Noise by Young Listeners With Normal Hearing and Older Listeners With Hearing Loss

Wilson, Richard H., McArdle, Rachel, Betancourt, Mavie B., Herring, Kaileen, Lipton, Teresa, Chisolm, Theresa H. 01 February 2010 (has links)
Background: The most common complaint of adults with hearing loss is understanding speech in noise. One class of masker that may be particularly useful in the assessment of speech-in-noise abilities is interrupted noise. Interrupted noise usually is a continuous noise that has been multiplied by a square wave that produces alternating intervals of noise and silence. Wilson and Carhart found that spondaic word thresholds for listeners with normal hearing were 28 dB lower in an interrupted noise than in a continuous noise, whereas listeners with hearing loss experienced only an 11 dB difference. Purpose: The purpose of this series of experiments was to determine if a speech-in- interrupted-noise paradigm differentiates better (1) between listeners with normal hearing and listeners with hearing loss and (2) among listeners with hearing loss than do traditional speech-in-continuous-noise tasks. Research Design: Four descriptive/quasi-experimental studies were conducted. Study Sample: Sixty young adults with normal hearing and 144 older adults with pure-tone hearing losses participated. Data Collection and Analysis: A 4.3 sec sample of speech-spectrum noise was constructed digitally to form the 0 interruptions per second (ips; continuous) noise and the 5, 10, and 20 ips noises with 50% duty cycles. The noise samples were mixed digitally with the Northwestern University Auditory Test No. 6 words at selected signal-to-noise ratios and recorded on CD. The materials were presented through an earphone, and the responses were recorded and analyzed at the word level. Similar techniques were used for the stimuli in the remaining experiments. Results: In Experiment 1, using 0 ips as the reference condition, the listeners with normal hearing achieved 34.0, 30.2, and 28.4 dB escape from masking for 5, 10, and 20 ips, respectively. In contrast, the listeners with hearing loss only achieved 2.1 to 2.4 dB escape from masking. Experiment 2 studied the 0 and 5 ips conditions on 72 older listeners with hearing loss, who were on average 13 yr younger and more varied in their hearing loss than the listeners in Experiment 1. The mean escape from masking in Experiment 2 was 7 dB, which is 20-25 dB less than the escape achieved by listeners with normal hearing. Experiment 3 examined the effects that duty cycle (0-100% in 10% steps) had on recognition performance in the 5 and 10 ips conditions. On the 12 young listeners with normal hearing, (1) the 50% correct point increased almost linearly between the 0 and 60% duty cycles (slope=4.2 dB per 10% increase in duty cycle), (2) the slope of the function was steeper between 60 and 80% duty cycles, and (3) about the same masking was achieved for the 80-100% duty cycles. The data from the listeners with hearing loss were inconclusive. Experiment 4 varied the interburst ratios (0, -6, -12, -24, -48, and -∞ dB) of 5 ips noise and evaluated recognition performance by 24 young adults. The 50% points were described by a linear regression (R2=0.98) with a slope of 0.55 dB/dB. Conclusion: The current data indicate that interrupted noise does provide a better differentiation both between listeners with normal hearing and listeners with hearing loss and among listeners with hearing loss than is provided by continuous noise.
22

Interrupted Monosyllabic Words: The Effects of Ten Interruption Locations on Recognition Performance by Older Listeners With Sensorineural Hearing Loss

Wilson, Richard H., Sharrett, Kadie C. 01 January 2017 (has links)
Background: Two previous experiments from our laboratory with 70 interrupted monosyllabic words demonstrated that recognition performance was influenced by the temporal location of the interruption pattern. The interruption pattern (10 interruptions/sec, 50% duty cycle) was always the same and referenced word onset; the only difference between the patterns was the temporal location of the onand off-segments of the interruption cycle. In the first study, both young and older listeners obtained better recognition performances when the initial on-segment coincided with word onset than when the initial on-segment was delayed by 50 msec. The second experiment with 24 young listeners detailed recognition performance as the interruption pattern was incremented in 10-msec steps through the 0-To 90-msec onset range. Across the onset conditions, 95% of the functions were either flat or U-shaped. Purpose: To define the effects that interruption pattern locations had on word recognition by older listeners with sensorineural hearing loss as the interruption pattern incremented, re: Word onset, from 0 to 90 msec in 10-msec steps. Research Design: A repeated-measures design with ten interruption patterns (onset conditions) and one uninterruption condition. Study Sample: Twenty-four older males (mean = 69.6 yr) with sensorineural hearing loss participated in two 1-hour sessions. The three-frequency pure-Tone average was 24.0 dB HL and word recognition was $80% correct. Data Collection and Analyses: Seventy consonant-vowel nucleus-consonant words formed the corpus of materials with 25 additional words used for practice. For each participant, the 700 interrupted stimuli (70 words by 10 onset conditions), the 70 words uninterrupted, and two practice lists each were randomized and recorded on compact disc in 33 tracks of 25 words each. Results: The data were analyzed at the participant and word levels and compared to the results obtained earlier on 24 young listeners with normal hearing. The mean recognition performance on the 70 words uninterrupted was 91.0% with an overallmean performance on the ten interruption conditions of 63.2% (range: 57.9-69.3%), compared to 80.4% (range: 73.0-87.7%) obtained earlier on the young adults. The best performances were at the extremes of the onset conditions. Standard deviations ranged from 22.1% to 28.1% (24 participants) and from 9.2% to 12.8% (70 words). An arithmetic algorithm categorized the shapes of the psychometric functions across the ten onset conditions.With the older participants in the current study, 40% of the functions were flat, 41.4% were U-shaped, and 18.6% were inverted U-shaped, which compared favorably to the function shapes by the young listeners in the earlier study of 50.0%, 41.4%, and 8.6%, respectively. There were two words on which the older listeners had 40% better performances. Conclusion: Collectively, the data are orderly, but at the individual word or participant level, the data are somewhat volatile, which may reflect auditory processing differences between the participant groups. The diversity of recognition performances by the older listeners on the ten interruption conditions with each of the 70 words supports the notion that the term hearing loss is inclusive of processes well beyond the filtering produced by end-organ sensitivity deficits.
23

A feminist analysis of the dilemmas of women in relationships : a study of Reneilwe Malatji's love interrupted

Maenetja, Nelly January 2019 (has links)
Thesis (M. A. (English Studies)) --University of Limpopo, 2019 / The purpose of this research was to analyse and investigate the dilemmas of women in relationships in the literary text Love Interrupted by Reneilwe Malatji published in 2012, using the feminist framework. The study explores how women are negatively affected by their relationships with their partners/husbands. Furthermore, the study focuses on how they are disadvantaged by cultural and societal expectations and how difficult it is for them to live with their in-laws. The primary text, Love Interrupted, is analysed to answer the three research questions that this study raises. The three research questions are: (1) Does the influence of culture and society affect the women in the short stories? (2) Do the perceptions that extended family members have of women undermine and diminish their sense of self-worth in the short stories? (3) In what ways are the children in the short stories used by the women in adulterous and abusive relationships? Because the short stories are written by a woman writer, the anthology gives first-hand experience on the dilemmas that the women in the short stories find themselves in as far as relationships, cultural and societal expectations are concerned. This study employed a qualitative framework which applied critical content analysis in interpreting the short stories. The analysis focused on four short stories in the anthology: “Love Interrupted”, “The Things We Do for Love”, “Lebo’s story 1: A Young Girl’s Dream Interrupted” and “My Perfect Husband” set in the Bapedi culture of the Limpopo province The findings of the study are that women, especially those in the rural areas of South Africa, are expected to be submissive and subordinate to their spouses. As a result of this, cultural and societal expectations have disadvantaged them greatly. They find excuses to put up with their abusive and adulterous husbands in the name of raising their children with the male figure around, and mostly they stay in these relationships in order to earn respect from community members. The study also found other reasons why women in the short stories are forced to stay in the abusive and adulterous relationships with their spouses: financial instability, stigmatization of unmarried and divorced women, and cultural and societal expectations to be strong women. This study employed feminist theory in the analysis of the dilemmas of the women in the selected short stories. Feminist theory provided a lens through which to understand the women’s dilemmas. Through feminist theory, it becomes apparent that the women are subjected to male dominance and societal expectations which prescribe submissive roles for women. Thus, they are not in a position to question or challenge the cultural practices which denigrate them. Their opinion in matters is never sought; they are simply expected to comply with the interests of men. The feminist analysis of the short stories suggests that there is still a great need to continue the fight against gender inequality in South Africa.
24

Karen–Burmese Refugees’ Cultural Perception of Formal Education

Williams, Veronica A. 01 January 2017 (has links)
In the U.S. the population continues to diversify as refugees find residence within its borders. According to the U.S. Department of Education’s Refugee Resettlement Statistics (2012) of those refugees fourteen thousand and twenty identified themselves as Karen refugees from Burma. In the context of education, teachers are confronted with the language development of English Language Learners (ELLs). At the researchers school site the ELLs population include; immigrants, refugees, and Students with Interrupted Formal Education (SIFE). Although it is known that refugee students have limited formal education, which creates difficulty for them to access content and develop their English language proficiency (Decapua, Smathers, & Tang, 2009), there was a paucity of data of the cultural differences of Karen refugees’ parents experiences with formal education systems compared to those of other refugees. The researcher conducted an Interpretative Phenomenological Analysis (IPA) case study grounded in sociocultural theory (Vygotsky, 1978) with the aim to analyze the personal experience of Karen refugee women who relocated to an urban city located in the northeastern United States as parents of students in the U.S. public school system. After the conclusion of the study following dominant themes arose: family, limited formal education, communication and cultural representation. One major implication constituted the need for inclusion of families’ and students’ cultural knowledge into school systems and curriculum. Considering the cultural gap, it is important that teacher training programs and administrators prepare teachers with strategies for incorporating culturally responsive teaching practices into their pedagogy. Another implication of the study was communication between multilingual refugee families and American schools. Institutions working with refugee communities should prioritize interpreting and translation.
25

An impact evaluation of u.s. arms export controls on the u.s. defense industrial base an interrupted time-series analysis

Condron, Aaron 01 August 2011 (has links)
The United States Defense Industrial Base (USDIB) is an essential industry to both the economic prosperity of the US and its strategic control over many advanced military systems and technologies. The USDIB, which encompasses the industries of aerospace and defense, is a volatile industry - prone to many internal and external factors that cause demand to ebb and flow widely year over year. Among the factors that influence the volume of systems the USDIB delivers to its international customers are the arms export controls of the US. These controls impose a divergence from the historical US foreign policy of furthering an open exchange of ideas and liberalized trade. These controls, imposed by the Departments of Commerce, Defense, and State rigidly control all international presence of the Industry. The overlapping controls create an inability to conform to rapidly changing realpolitiks, leaving these controls in an archaic state. This, in turn, imposes a great deal of anxiety and expense upon managers within and outside of the USDIB. Using autoregressive integrated moving average time-series analyses, this paper confirms that the implementation of or amendment to broad arms export controls correlates to significant and near immediate declines in USDIB export volumes. In the context of the US's share of world arms exports, these controls impose up to a 20% decline in export volume.
26

OPTIMIZATION OF RARE-EARTH DOPED GALLIUM NITRIDE ELECTROLUMINESCENT DEVICES FOR FLAT PANEL DISPLAY APPLICATIONS

MUNASINGHE, CHANAKA D. 13 July 2005 (has links)
No description available.
27

Periodic Coalescence Filtration Performance of Thin Glass Filter Media

AlGhamdi, AbdulAziz A. 24 July 2022 (has links)
No description available.
28

Improved Methods for Interrupted Time Series Analysis Useful When Outcomes are Aggregated: Accounting for heterogeneity across patients and healthcare settings

Ewusie, Joycelyne E January 2019 (has links)
This is a sandwich thesis / In an interrupted time series (ITS) design, data are collected at multiple time points before and after the implementation of an intervention or program to investigate the effect of the intervention on an outcome of interest. ITS design is often implemented in healthcare settings and is considered the strongest quasi-experimental design in terms of internal and external validity as well as its ability to establish causal relationships. There are several statistical methods that can be used to analyze data from ITS studies. Nevertheless, limitations exist in practical applications, where researchers inappropriately apply the methods, and frequently ignore the assumptions and factors that may influence the optimality of the statistical analysis. Moreover, there is little to no guidance available regarding the application of the various methods, and a standardized framework for analysis of ITS studies does not exist. As such, there is a need to identify and compare existing ITS methods in terms of their strengths and limitations. Their methodological challenges also need to be investigated to inform and direct future research. In light of this, this PhD thesis addresses two main objectives: 1) to conduct a scoping review of the methods that have been employed in the analysis of ITS studies, and 2) to develop improved methods that address a major limitation of the statistical methods frequently used in ITS data analysis. These objectives are addressed in three projects. For the first project, a scoping review of the methods that have been used in analyzing ITS data was conducted, with the focus on ITS applications in health research. The review was based on the Arksey and O’Malley framework and the Joanna Briggs Handbook for scoping reviews. A total of 1389 studies were included in our scoping review. The articles were grouped into methods papers and applications papers based on the focus of the article. For the methods papers, we narratively described the identified methods and discussed their strengths and limitations. The application papers were summarized using frequencies and percentages. We identified some limitations of current methods and provided some recommendations useful in health research. In the second project, we developed and presented an improved method for ITS analysis when the data at each time point are aggregated across several participants, which is the most common case in ITS studies in healthcare settings. We considered the segmented linear regression approach, which our scoping review identified as the most frequently used method in ITS studies. When data are aggregated, heterogeneity is introduced due to variability in the patient population within sites (e.g. healthcare facilities) and this is ignored in the segmented linear regression method. Moreover, statistical uncertainty (imprecision) is introduced in the data because of the sample size (number of participants from whom data are aggregated). Ignoring this variability and uncertainty will likely lead to invalid estimates and loss of statistical power, which in turn leads to erroneous conclusions. Our proposed method incorporates patient variability and sample size as weights in a weighted segmented regression model. We performed extensive simulations and assessed the performance of our method using established performance criteria, such as bias, mean squared error, level and statistical power. We also compared our method with the segmented linear regression approach. The results indicated that the weighted segmented regression was uniformly more precise, less biased and more powerful than the segmented linear regression method. In the third project, we extended the weighted method to multisite ITS studies, where data are aggregated at two levels: across several participants within sites as well as across multiple sites. The extended method incorporates the two levels of heterogeneity using weights, where the weights are defined using patient variability, sample size, number of sites as well as site-to-site variability. This extended weighted regression model, which follows the weighted least squares approach is employed to estimate parameters and perform significance testing. We conducted extensive empirical evaluations using various scenarios generated from a multi-site ITS study and compared the performance of our method with that of the segmented linear regression model as well as a pooled analysis method previously developed for multisite studies. We observed that for most scenarios considered, our method produced estimates with narrower 95% confidence intervals and smaller p-values, indicating that our method is more precise and is associated with more statistical power. In some scenarios, where we considered low levels of heterogeneity, our method and the previously proposed method showed comparable results. In conclusion, this PhD thesis facilitates future ITS research by laying the groundwork for developing standard guidelines for the design and analysis of ITS studies. The proposed improved method for ITS analysis, which is the weighted segmented regression, contributes to the advancement of ITS research and will enable researchers to optimize their analysis, leading to more precise and powerful results. / Thesis / Doctor of Philosophy (PhD)
29

Räntehöjningens påverkan på skuldsättningsgrad: En studie av amerikanska industriföretag / The Impact of Interest Rate Increases on Debt Ratios: A Study of US Industrial Companies

Hagström, Robin, Flink, Vincent January 2024 (has links)
This study aims to investigate the impact of central bank interest rate effects on the debt-to-equity ratio of major companies in the industrial sector. With an Interrupted Time Series analysis the research examines how changes in the Federal Reserve's policy rates between 2011 and 2019 have influenced corporate financial strategies. Data from 46 of the largest U.S-based industrial firms were analyzed to identify trends in debt ratio before and after interest rate changes. The method involved comparing debt-to-equity ratios over a period of 36 quarters capturing both pre-event and post-event data. The findings indicate an increase in interest led to an increase in the debt ratio among these firms. This suggests that companies may have acted proactively to secure lower debt cost ahead of anticipated rate increases contrary to traditional expectations that higher rates would reduce borrowing. The study concludes that such proactive financial behavior highlights the complexity of corporate decision making in response to macroeconomic policy changes. The results contribute to a deeper understanding of how industrial firms manage their capital structure under varying economic conditions. Future research should explore sector specific responses and the implications for smaller firms to provide a more comprehensive view of the impact of interest rate changes on corporate capital structure. / Denna studie undersöker hur centralbankernas räntehöjningar påverkar skuldsättningsgraden hos stora företag inom industrisektorn. Genom att använda en Interrupted Time Series (ITS)-analys undersöker forskningen hur förändringar i Federal Reserves styrräntor mellan 2011 och 2019 har påverkat företagens finansiella strategier. Data från 46 av de största industriföretagen baserade i USA analyserades för att identifiera trender i skuldsättningen före och efter ränteändringarna. Metodstycket innebar en jämförelse av skuldsättningsgrader över en period av 36 kvartal vilket omfattade både data före och efter ränteändringarna. Resultaten visar på en ökning av skuldsättningsgraden bland dessa företag efter räntehöjningarna. Detta tyder på att företagen kan ha agerat proaktivt för att säkra billigare lån innan de förväntade räntehöjningarna fullt ut realiserades i motsats till den traditionella förväntningen att högre räntor skulle minska belåningen. Studien drar slutsatsen att ett sådant proaktivt finansiellt beteende belyser komplexiteten i företagens beslutsfattande som svar på makroekonomiska politiska förändringar. Resultaten bidrar till en djupare förståelse för hur industriföretag hanterar sin kapitalstruktur under varierande ekonomiska förhållanden. Framtida forskning bör utforska sektorspecifika svar och implikationerna för mindre företag för att ge en mer heltäckande bild av hur ränteförändringar påverkar företagens kapitalstruktur.
30

Impact of the cefazolin shortage on the selection and cost of parenteral antibiotics during the supply disruption period in Japan: A controlled interrupted time series analysis / 日本における供給停止期間中のセファゾリン不足が注射抗菌薬の選択と費用に与えた影響: 対照群を置いた分割時系列解析

Nagano, Hiroyuki 25 March 2024 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第25156号 / 医博第5042号 / 京都大学大学院医学研究科医学専攻 / (主査)教授 川上 浩司, 教授 森田 智視, 教授 寺田 智祐 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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