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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.
521

Motorists´evaluation of road maintenance management

Olsson, Camilla January 2003 (has links)
<p>The road network is extremely valuable. Road Administrationsare expected to invest maintenance funding in a way thatreturns maximum benefit to road users. Cost-benefit analysis isone method to ensure that an adequate return in terms ofbenefits results from committing expenditure. Today,cost-benefit calculations are frequently used as a base fordecision making of investments. The surges for such methods inthe maintenance management sector are increasing.</p><p>Up to the present, one reason for not analysing costs andbenefits for various maintenance management measures has beenthe lack of knowledge about comfort benefits for road users inquantitative monetary terms. The aim with this thesis is toinvestigate motorists’apprehension of pavementmaintenance management and winter maintenance operations. Thefinal goal is to find out their willingness to pay fordifferent levels of road maintenance management. Those valuescan later be used in cost-benefit calculations and also ineffect models of road maintenance management.</p><p>Due to the pioneer status of this study, focus groups andin-depth interviews as well as a number of pilot studies havebeen carried out before a main survey with stated choiceexperiments could be designed. These exploratory studies showedthat the interviewees were familiar with the types of roadsurface damage that exist and in many cases mastered the sameterminology as the Road Administration and others. Showingpictures of well-known types of road damage lead to highermonetary valuations of getting better road standard incomparison with just text descriptions. One reason for thatcould be the requisite severness of the damage in order toillustrate a certain road maintenance shortage. The respondentswith the text descriptions could have stated their preferencesfor an, in their own minds, average shortcoming while the groupwith access to photograph of road damage all saw the samesevere damage. Illustrations of different road maintenancestandards make it possible to control the respondentsinterpretation of the maintenance management standard valuatedbut could lead to high monetary estimations.</p><p>Driving comfort was very important to the interviewees inthe exploratory studies. That was manifested in the pilotstated choice surveys, which resulted in high willingness topay for better pavement management.</p><p>The main study consisted of two surveys; the first one wasabout pavement maintenance management and was carried out inOctober to November 2000 and the second one took place inFebruary to March 2001 and was about winter maintenanceoperations. Both the pavement and the winter survey includedattitude questions and two stated choice experiments. Theresult showed that the maintenance management status of theroad network was important to car users. For example, the worstpavement damage was roughness; the motorists were willing topay 1.7 SEK (Swedish Crowns) per kilometre to avoid roadsdamaged in their full length. The least harmful damage of thosestudied was cracks; the willingness to pay to avoid that was0.5 SEK per kilometre. For more rapid snow clearance, the carusers were willing to pay 60 to 80 SEK per year for getting theroads cleared from snow one hour earlier than the currentstandard implies. The willingness to pay for driving on bareroads in comparison with snow roads was 0.4 SEK per kilometre.Statistical tests on the models showed that the parametervalueswere well estimated.</p><p>In the pavement as well as in the winter survey, a clustergroup analysis was performed in order to test the heterogeneityof attitudes and behaviour to road maintenance management. Theanalysis resulted in two separate groups in each survey. Onegroup consisted of drivers who reported to be very influencedby the level of maintenance management regarding chosen speed,joy of driving and so on. The other group reported to be lessinfluenced and had lower acceptance of higher road tax for thepurpose to increase the maintenance management standard.Separate stated choice models revealed that the differences inattitudes could also reflect the respondents’willingnessto pay for higher road maintenance standard. However, thedifferences were only small and the different groups’monetary valuations were not found to be significantlydifferent from each other.</p><p>The result of this study, better knowledge aboutmotorists’apprehension of maintenance management, theirattitudes to driving comfort and road standard and theirmonetary valuations of different levels of pavement maintenanceand winter maintenance operations, opens up the possibility tomake cost-benefit analysis of various maintenance managementprojects. The impact of the monetary values found in this studyhas been studied in a limited cost-benefit analysis.</p><p><b>Keywords:</b>stated choice, stated preference, valuationsof maintenance management, driving comfort, road standardevaluation</p>
522

Less is more? Loudness aspects of prescriptive methods for nonlinear hearing aids

Smeds, Karolina January 2004 (has links)
<p>In Sweden, about 10% of the adult population experienceshearing problems that cause them difficulties in everydaycommunication, and approximately 60 000 people are providedwith hearing aids each year. Despite the fact that modernhearing aids can facilitate speech communication in a widerange of listening environments, many hearing-aid users aredissatisfied with their hearing aids. It is likely that theclinical methods used for individual fitting of the hearingaids are not optimal.</p><p>The current study investigates prescriptive methods fornonlinear, wide dynamic range compression (WDRC) hearinginstruments. The goal is to draw general conclusions about thepreferences of hearing aid users. Therefore, the prescriptionsare evaluated using well-established models of loudness andspeech intelligibility.</p><p>Current methods differed considerably in prescribed gain.Evaluations in a laboratory test, with 20 hearing-impairedlisteners, showed that these differences led to largedifferences in perceived and calculated loudness, but only tominor differences in measured and predicted speech recognitionscores. The difference in loudness was explored in a studywhere 21 first-time hearing-aid users compared twoprescriptions. One method led to normal and the other toless-than-normal overall calculated loudness (according to theloudness model of Moore and Glasberg (1997)). The prescriptionthat led to less-than-normal overall loudness was clearlypreferred in field and in laboratory tests.</p><p>Preferred overall loudness was then quantified.Hearing-impaired participants with mild to moderate hearingloss preferred considerably less-than-normal overall calculatedloudness in both eld and laboratory tests. There were nosignificant differences between inexperienced and experiencedhearing aid users. Normal-hearing participants, on the otherhand, preferred close-to-normal overall calculated loudness. Inaddition, a potential problem with the loudness model wasencountered: despite the fact that the hearing-impairedlisteners were provided with less than normal overallcalculated loudness, they rated loudness higher than thenormal-hearing listeners.</p><p>The results refute the most commonly adopted rationale forprescriptive methods for WDRC hearing aids - that overallloudness should be restored to normal. Hearing-impairedlisteners with mild to moderate hearing loss preferredconsiderably less than normal overall loudness. This should betaken into account when deriving new prescriptive methods, andwhen providing clients with hearing aids.</p><p><b>Key words:</b>hearing impairment, hearing aid, nonlinear,WDRC, hearing aid experience, prescription, loudness, loudnessmodel, speech intelligibility, preference.</p>
523

Detecting Aberrant Responding on Unidimensional Pairwise Preference Tests: An Application of based on the Zinnes Griggs Ideal Point IRT Model

Lee, Philseok 01 January 2013 (has links)
This study investigated the efficacy of the lz person fit statistic for detecting aberrant responding with unidimensional pairwise preference (UPP) measures, constructed and scored based on the Zinnes-Griggs (ZG, 1974) IRT model, which has been used for a variety of recent noncognitive testing applications. Because UPP measures are used to collect both "self-" and "other-" reports, I explored the capability of lz to detect two of the most common and potentially detrimental response sets, namely fake good and random responding. The effectiveness of lz was studied using empirical and theoretical critical values for classification, along with test length, test information, the type of statement parameters, and the percentage of items answered aberrantly (20%, 50%, 100%). We found that lz was ineffective in detecting fake good responding, with power approaching zero in the 100% aberrance conditions. However, lz was highly effective in detecting random responding, with power approaching 1.0 in long-test, high information conditions, and there was no diminution in efficacy when using marginal maximum likelihood estimates of statement parameters in place of the true values. Although using empirical critical values for classification provided slightly higher power and more accurate Type I error rates, theoretical critical values, corresponding to a standard normal distribution, provided nearly as good results.
524

The therapy hour in black and white : an exploration of counselor preference and cultural mistrust among African American students

Holman, Andrea Chantal 25 September 2013 (has links)
This study explored interpersonal trust, racial identity, perceived racism, and religious orientation as predictors of preference for a Black counselor and cultural mistrust. The unique variance of interpersonal trust and cultural mistrust in predicting preference for a Black counselor was also explored. The relationship between cultural mistrust and interpersonal trust was tested to determine whether or not they are independent constructs. This study also examined the relationship between racial identity and religious orientation. Gender differences in religious orientation, cultural mistrust and preference for a Black counselor were examined. Previous studies provide support that cultural mistrust contributes to negative help-seeking attitudes and underutilization of mental health services. Researchers have identified racial identity and perceived racism as correlates to and/or predictors of cultural mistrust and preference for a Black counselor (Whaley, 2001). This study involved participants recruited in part from the Educational Psychology (EDP) Subject Pool at The University of Texas at Austin (UT). Participants were also recruited from five student organizations at UT. Participants completed the survey using an online survey tool or a paper copy of the survey. One stratum was used for selection of participants: students who racially identify as African-American or Black. Results of the study revealed interpersonal trust as a significant predictor of preference for a Black counselor. However, exploratory analyses indicated that cultural mistrust served as the sole predictor of Black counselor preference when seeking a counselor for dealing with racial concerns. Interpersonal trust, immersion-emersion anti-white racial identity attitudes (IEAW) and extrinsic religious orientation were significant predictors of cultural mistrust. Results also indicated a positive relationship between Internalization Multiculturalist (IMCI) racial identity attitudes and intrinsic religious orientation. A negative correlation was found to exist between intrinsic religious orientation and IEAW. High cultural mistrust levels were also positively associated with high IEAW attitudes. Additionally, a small, yet statistically significant negative relationship was found to exist between cultural mistrust and interpersonal trust. Cultural mistrust did not account for a significant amount of variance above that of interpersonal trust in predicting preference for a Black counselor. Finally, no mean sex differences were found among levels of Black counselor preference, cultural mistrust, and intrinsic or extrinsic religious orientation. Exploratory analyses also revealed a positive relationship between cultural mistrust and seven out of ten scenarios for Black counselor preference. Individuals with a preference for a Black counselor reported higher levels of cultural mistrust related to issues concerning: excessive worry/anxiety, drinking too much alcohol/using drugs, relationship problems, feelings of harassment/feeling threatened, sexual issues, racial issues, and difficulty controlling anger. Results of the study bear implications for understanding cultural mistrust and interpersonal trust as it relates to counselor preference. Implications for counselors are also discussed regarding the intersection of racial and religious identities. Limitations and future directions for research are also discussed. / text
525

A role for the medial preoptic area in mediating a response to cocaine

Tobiansky, Daniel Jonathan 15 January 2015 (has links)
The salience of natural or drug-associated reward is mediated by phasic dopamine (DA) release in the nucleus accumbens (NAc) arising from DAergic cells in the ventral tegmental area (VTA). Circulating sex steroid hormones can modulate reward associated with drugs of abuse; yet, it still remains unclear which brain regions are responsible for this modulation. The medial preoptic area (mPOA) is a hypothalamic brain area involved in the expression of naturally rewarding behaviors as well as the regulation and reception of circulating sex steroid hormones in female rats. Considering its role in regulating naturally rewarding behaviors, its well-established anatomical connectivity with the VTA, and its responsiveness to circulating sex steroid hormones, the mPOA is an ideal neural node through which hormones could modulate the rewarding facets of drugs of abuse. Here I show that preoptotegmental efferents to the VTA are primarily GABAergic, that they appose putative DAergic cell bodies in the VTA that project to the NAc, and that they are capable of responding to sex steroid hormones and changes in DA release. Furthermore, cocaine influences neural activity in mPOA efferents that project to the VTA. Removal of the mPOA also enhanced cocaine-induced locomotion, Fos-immunoreactivity in the mesolimbic reward system, DA release in the NAc, and augmented conditioned place preference. Together these findings suggest that the mPOA modulates the release of DA in the mesolimbic reward circuitry via inhibitory connections with DA neurons residing in the VTA, and sex steroid hormones, in turn, may act in the mPOA to modulate response to cocaine. / text
526

The role of sexual imprinting in speciation: lessons from deer mice (genus Peromyscus)

Kay, Emily Ho 21 October 2014 (has links)
Sexual imprinting, the process of learning mate preferences at a young age, could promote speciation by reducing attraction to individuals from divergent populations or species, consequently creating or maintaining reproductive isolation. Yet, despite the documentation of sexual imprinting in many taxa, its connection to speciation has been understudied. I chose to explore the potential link between sexual imprinting and reproductive isolation and in two North American rodents--the white-footed mouse (Peromyscus leucopus) and its sister species, the cotton mouse (Peromyscus gossypinus). These species have overlapping distributions in nature, possibly allowing interbreeding and admixture. In Chapter 1, I used double-digest restriction-associated DNA sequencing to test for hybridization in sympatric natural populations and found that 1.5% of sampled individuals showed evidence of admixture yet the species have maintained genetic distinctness in sympatry. In the lab, the species hybridize when given no choice of mates but mate more readily with conspecifics, suggesting that mating preferences may prevent hybridization in the wild. In Chapter 2, I tested whether mating preferences create significant reproductive isolation. I measured mating preferences in controlled laboratory conditions and found that both species and sexes preferred conspecific to heterospecific mates in 85% of trials. I then raised offspring with foster parents of the opposite species and found that P. leucopus has a genetically-determined preference while P. gossypinus learns its preference. In Chapter 3, I tested whether sexual imprinting on parental diet could generate assortative mating within a species. I tested this hypothesis by feeding P. gossypinus parents either orange- or garlic-flavored water, thereby exposing their offspring to these flavors through their parents until weaning. I tested the preferences of these offspring as adults and found that P. gossypinus, especially females, had strong assortative mating preferences. This implies that at least females learn parental dietary information and that assortative mating could evolve within a single generation. Together, my results confirm that sexual imprinting on parental traits--possibly mediated through dietary differences--can create assortative mating capable of generating sexual isolation and reducing gene flow between species. My research supports the importance of mating preferences and learning in speciation.
527

Comparison of ethanol-related behaviors and FosB mapping in hybrid mice with distinct drinking patterns

Ozburn, Angela Renee 27 January 2011 (has links)
Distinct alcohol self-administration behaviors are observed when comparing two F1 hybrid strains of mice: C57BL/6J x NZB/B1NJ (B6xNZB) show reduced alcohol preference (RAP) after experience with high concentrations of alcohol and abstinence periods and C57BL/6J x FVB/NJ (B6xFVB) show sustained alcohol preference (SAP), providing models of stable, high alcohol consumption and moderate drinking. The purpose of this dissertation is to characterize ethanol-related behaviors and define neurocircuits engaged by SAP and RAP. We performed a battery of behavioral tests to define behaviors that predict SAP and RAP. B6xFVB exhibited less severe ethanol-induced conditioned taste aversion and were less sensitive to ethanol-induced loss of righting reflex (LORR) than B6xNZB. Both hybrids demonstrated ethanol-induced place preference and low ethanol withdrawal severity. Hybrids differ in sensitivity to the aversive and sedative, but not rewarding, effects of ethanol. Results of elevated plus maze, mirror chamber, and locomotor tests reveal B6xFVB mice are less anxious and more active than B6xNZB mice. The validity of the SAP behavioral phenotype in B6xFVB mice was determined by testing whether chronic self-administration of ethanol produced tolerance or dependence. We measured responses from ethanol-naïve and ethanol-experienced mice in tests of ethanol-induced hypothermia, withdrawal severity, and LORR. Chronic ethanol self-administration resulted in tolerance to sedative and hypothermic effects of ethanol; however, physical dependence was not evident as measured by ethanol withdrawal severity. We tested the hypothesis that SAP and RAP behavioral differences are represented by differential production of the inducible transcription factor, FosB. FosB immunoreactivity was quantified in 16 brain structures after chronic ethanol consumption or only water. Neuronal activity (as measured by FosB levels) depended on ethanol experience, brain region, and genotype, further supporting the notion that neuronal circuitry underlies motivational aspects of ethanol consumption. For B6xNZB mice, ethanol consumption resulted in increased neuronal activity in the EW, VTA, and amygdala, known ethanol- reward-, and stress-related brain regions. In B6xFVB, ethanol consumption resulted in a larger network of correlated regional activity, whereas in B6xNZB ethanol consumption resulted in a smaller network. These studies characterized genetic models of stable, high consumption (SAP) and moderate drinking (RAP) in two hybrid mouse strains. / text
528

Preference and performance in a population of checkerspot butterflies with known diet history

Hasanah, Nur 14 February 2011 (has links)
This thesis describes a relationship between maternal preference and offspring performance in a population of the butterfly Euphydryas editha that used two host plants, Pedicularis semibarbata and Collinsia torreyi from 1979 to 2001, but now no longer uses Collinsia. In the light of the known history of diet change in this butterfly population, it is not surprising that maternal oviposition preference was variable. Although the diet of the butterflies that evolved rapidly in the 1980’s is no longer changing, I still discovered some females with a chemical preference for Collinsia. This seems to be a legacy of recent anthropogenic diet evolution. The evolution of host preference of females in Rabbit Meadow has not finished yet. Variation of offspring weight and survival were measured and showed a complex relationship with adult preference. Although quite a few adults strongly rejected Collinsia, their offspring grew well on this host, and there was no significant trend for the offspring of strongly Pedicularis-preferring butterflies to perform more poorly on Collinsia. / text
529

Investigating the female mate preference brain : identifying molecular mechanisms underlying variation in mate preference in specific regions of a swordtail (Xiphophorus nigrensis) brain

Wong, Ryan Ying 02 June 2011 (has links)
Choosing with whom to mate is one of the most important decisions a female makes in her lifetime and inter-individual variation of these preferences can have important evolutionary consequences. In order to get a complete understanding of why and how females choose a mate, we must identify factors that can contribute to variation of female mate choice. Many decades of research sought to understand ultimate mechanisms of female mate choice with proximate mechanisms receiving a lot more attention in recent years. For my thesis, I identify intrinsic and extrinsic factors that correlate with individual variation of female Xiphophorus nigrensis mate preference. I provide evidence that a female’s size (e.g. age and sexual experience) as well as male behavioral displays can predict female mate preference. Using genes associated with female mate preference (neuroserpin, neurologin-3), I identify four brain regions (Dl, Dm, HV, POA) that show significant differences in gene expression between females exhibiting high preference for males relative to females displaying little mate preference. Neuroserpin and neuroligin-3 gene expression within these brain regions are also positively correlated with female mate preference behavior. Two of these brain regions (Dm and Dl) integrate multisensory information and are found in the putative teleost mesolimbic reward circuitry; the other two regions (HV and POA) are involved in sexual behaviors. With the implication of the reward circuitry, I assess whether there are changes in dopamine synthesis (via tyrosine hydroxylase, TH) in dopaminergic brain regions associated with the degree of mate preference. I do not find evidence of rapid changes (within 30 minutes) of TH expression (i.e. dopamine synthesis) in dopaminergic brain regions related to variation in female mate preference. Collectively my results suggest that mate preference behavior in the brain may be coordinated not just through regions associated with sexual response but also through forebrain areas that may integrate primary sensory information, with no associated changes of a proxy for dopamine synthesis in dopaminergic brain regions. / text
530

Consumer preference measurement and its practical application for selecting software product features

Ayers, Debra Lynn 07 November 2011 (has links)
Consumer preference measurement is a quantitative field of study for modeling, collecting and analyzing product decisions by consumers. Discovering how consumers choose products is an important area of marketing research and recognized as a successful partnership between academic theory and practice over the past forty years. Despite preference measurement’s success in consumer products, little guidance is available for its application to software product management. This paper assesses the feasibility of applying advanced preference measurement techniques to software products and suggests a framework for conducting such studies. A summary of the methods is provided to give guidance to software product managers seeking to apply preference measurement to common product decisions. The paper concludes by recommending a technique called ‘maximum difference scaling’ to elicit customer feedback to help measure the importance of new features for software product improvement. / text

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