• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 1
  • 1
  • Tagged with
  • 283
  • 283
  • 140
  • 107
  • 95
  • 63
  • 62
  • 62
  • 59
  • 52
  • 36
  • 29
  • 28
  • 23
  • 22
  • 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.
1

Conditional Immunomodulation

MacQueen, Marlene Glenda January 1989 (has links)
<p>Interest in central nervous-immune system interactions was inspired largely by the work on conditional immunomodulation (Ader and Cohen, 1975, 1985). Ader and Cohen (1975) reported that rats trained such that a taste cue (saccharine, SAC) predicted an injection of an immunosuppressant (cyclophosphamide, CY) subsequently exhibited a conditional immunosuppression in response to SAC alone.</p> <p>Experiments 1-3 were designed to evaluate reports of conditional immunosuppression after training with SAC and CY. Rats received either one or three training sessions in which SAC presentation was followed by CY injection. Upon reexposure to the SAC, antibody formation to sheep red blood cells was assessed. Rats which were trained with SAC and CY had antibody titers that did not differ from saline controls, which rats which SAC and CY in a nonpredictive manner had suppressed antibody titers.</p> <p>Experiments 4 and 5 assessed the effectiveness of environmental and drug state cues in signalling CY injections. In Experiments 4 and 5, the effect of training was to attenuate the unconditional immunosuppression produced by the CY.</p> <p>Experiments 6 and 7 further assessed conditioning with pentobarbital predicting CY. After conditioning, some animals were rested until the residual effects of the CY had dissipated. When reexposed to the pentobarbital after this period, these animals had antibody titers that were significantly elevated above those of animals that never received the CY. Other animals received seven pentobarbital injections during the rest period. These animals demonstrated extinction of the conditioned response.</p> <p>Experiment 8 assessed the effectivness of conditioning when the unconditional stimulus was antigenic rather than pharmacologic. After sensitization, rats received antigen injections paired with an environmental cue. Upon reexposure to the cue, trained rats had increased levels of rat mast cell protease II in their serum. As this protease is found only in mucosal mast cells, these results suggest that mucosal mast cells may be activated by a cue for antigen.</p> <p>In a final experiment, physiological correlates of conditional mast cell activity were examined. Ussing chambers were employed to assess responsivity of intestinal epithelium after exposure to a cue for antigen. Results indicated that sensitivity to in vitro antigen was altered in rats exposed to a cue for antigen. These results, and those of the previous studies, support the hypothesis that the nervous and immune systems communicate, and that this communication may be functionally important.</p> / Doctor of Philosophy (PhD)
2

Social Feeding in Burmese Junglefowl (Gallus gallus spadiceus)

McQuoid, Marie Laurel 12 1900 (has links)
<p>There is reason to believe that birds feeding in flocks enjoy several different types of advantage relative to birds that feed alone. Most relevant to this thesis, flocking can facilitate individual birds' discovery of potential foraging sites. In the present research, both the long-term consequences of social feeding socially were examined in Burmese junglefowl (Gallus gallus spadiceus). The results of experiments presented in Chapter 2 indicated that junglefowl can learn to select either a type of feeding site or a location in which to feed simply by observing feeding companions. Social interaction biased the foraging behaviour of fowl for at least two days after interaction occurred.</p> <p>In experiments described in Chapter 3, junglefowl used information acquired during the exposure to videotaped companions to orient their own subsequent feeding behaviour. Different aspects of the feeding behaviours of video-taped tutor fowl influenced different aspects of their observers' feeding behaviour. For example, during testing, observer birds' latencies to initiate pecking were reduced by pervious exposure to the sight of conspecifics feeding, while the orientation of observers' pecking was influenced only when observers had both seen and heard feeding companions. The final study, presented in Chapter 4, indicated that observer fowl, even while feeding, were themselves able to learn about foraging sites where videotaped companions fed.</p> / Doctor of Philosophy (PhD)
3

Developmental and Individual Differences in Children's Reading Comprehension

Hinchley, Janet Louise 09 1900 (has links)
<p>This thesis research focused on the contributions of word decoding from print and of reliance on story organization to children's story comprehension. Two experiments were conducted, whose findings contribute to our understanding of developmental and individual differences in reading comprehension. In Experiment 1, children in Grades 3 to 6 read silently, read orally, or listened to well-organized and poorly organized stories. Both amount recalled and reliance on text organization increased with grade. Listening, which required no analysis of print, yielded equivalent comprehension to silent reading; demonstrating that differences in reading comprehension cannot be attributed only to differences in word-decoding skills. Furthermore, oral reading which required the decoding of each word in text, improved the comprehension and recall of good stories, especially for the poorest comprehenders. At each grade level a group of poor readers was identified who showed little sensitivity to story organization, in either silent reading or listening.</p> <p>In the second experiment, the nature of the oral-reading benefit was examined by having Grade 6 poor readers read well-organized and poorly organized stories silently and aloud. The experiment showed that oral reading increased recall for well-organized, but not for poorly organized text. This finding suggests that oral reading served to increase text organization, rather than to direct attention to the word level. The poorest comprehenders also gained from an advance organizer that stressed the problem structure of the stories.</p> <p>The first experiment identified children in each grade, up to Grade 6, who did not spontaneously rely on story organization in reading and remembering stories. The second experiment showed, however, that when story organization was made available and salient, such children were able to use it to help them read and remember stories. Finally, the results of Experiment 2 demonstrated the importance of specific diagnosis prior to developing treatment programs for poor readers.</p> / Doctor of Philosophy (PhD)
4

The Relationship Between Type A Coronary-Prone Behavior Pattern, Achievement, and Life Satisfaction

Felland, Larraine A. 01 January 1981 (has links)
This study examined the relationship between Type A coronary-prone behavior pattern, academic achievement and life satisfaction. The subjects were 87 undergraduates selected for their extreme scores on the Jenkins Activity Survey, Form T. There were 41 Type As and 46 Type Bs. Along with the Jenkins Activity Survey, Form T the participants were administered a life satisfaction survey similar to Soper's (1979) and their official academic gradepoint average was obtained from the Academic Records office. A point-biserial correlation indicated that there was a significant (p The various relationships and their possible explanations and indications were discussed in depth. Significance of the results for changing Type A behavior was considered. Problems and suggestions for future research were mentioned briefly.
5

The Effect of the Interviewer's Status Upon the Linguistic Style and Impact Messages Cenerated by the "Obsessive Personality"

Greenwood, VIncent B. 01 January 1978 (has links)
The present study addressed some of the peripheral statements emanating from Kiesler’s (Kiesler, Bernstein & Anchin, 1976) core communications theory by examining (1) a specific component of the communication style of the obsessive personality, (2) the distinctive emotional engagements the obsessive personality elicits when interacting with others, and (3) a situational determinant that is hypothesized to trigger relatively intense expression of the obsessive’s self-defeating communication style, as well as a higher level of state anxiety. Specifically, the study examined the effects of a high or low status interviewer upon one expressive measure of speech and upon relationship consequences for groups of psychometcially-defined obsessives and non-obsessives. The speech measure used was the revised edition of the Modifiers category of the Psycholinguistic Scoring System for the Obsessive Personality (Kiesler, Moulthrop & Todd, 1972). Modifiers, representing expressions of doubt and uncertainty, were hypothesized to occur more frequently in psychometrically-identified obsessive personalities, particularly in the high status interviewer condition. The emotional reactions evoked in others by an indecisive communication style were assessed by the Impact Message Inventory-Modifier Scale (Greenwood, 1976). It was hypothesized that more intense emotional reactions synonymous with an indecisive communication style would be elicited in observers by the obsessives, particularly in the high status interviewer condition. A wide range of emotional reactions evoked by the obsessive personality were assessed using the Impact Message Inventory (Kiesler, Anchin, Perkins, Chirico, Kyle & Federman, 1976). Finally, the state anxiety of all subjects was assessed before and after the experimental interview using the Anxiety-State Scale of the State Trait Anxiety Inventory (Speilberger, Gorsuch & Lushene, 1970). Here again it was predicted that obsessives would display a higher level of state anxiety, especially in the high-status interviewer condition. None of the experimental hypotheses were supported. The results for the predictions were discussed. It was suggested that the experimental analogue situation may not have been appropriate in some respects, particularly with regard to whether the subject selection criteria were adequate in producing a theoretically and clinically relevant group of subjects. Suggestions were offered to mitigate the possible flaws in the present analogue study. It was noted that the nature of the communication task appears to play a large role in the distinctive communication behavior that is evoked and, therefore, that communication task variables should be investigated in future studies. Finally, it was recommended that single-case design studies, using actual obsessive patients, might be the most viable strategy to study theoretical constructs vis a vis the obsessive personality.
6

An Investigation of Central Nervous System Conduction Properties in Diabetes Mellitus Using Brainstem Auditory and Somatosensory Evoked Potentials

Anderson, Randy L. 01 January 1981 (has links)
In this study brainstem auditory evoked potentials (BAEPs), median nerve conduction velocities (CV) and early somatosensory evoked potentials ( SEPs), were employed as indices of neural conduction properties in a group of young insulin dependent diabetics (five males and five females) and a group of nondiabetic controls (five males and five females). The median nerve CV was determined from 64 summated nerve responses recorded at the elbow. The nerve was stimulated at the wrist using 0.2 msec square wave electrical pulses. The SEP was recorded from scalp electrodes using the same median nerve stimulation technique as for the CV measure. The BAEPs were produced by recording responses to 7 0 dB SL clicks delivered to the right ear at a rate of 10 per second. Measures of central transmission time were determined from each of the EP modalities. The time interval between BAEP waves I and V determined the BAEP CTT. SEP waves P9 to Pl4 determined the earliest SEP CTT measure. Comparisons between the two diagnostic groups yielded the following results: The diabetic group evidenced a significant (p = 0, 02) slowing of the median nerve, 53 meters per second for the diabetic group versus 59 meters per second for the nondiabetic group. With height covaried out, only the SEP Pl4 latency showed a significant diagnostic group difference. More interesting were the findings for the principal SEP CTT measure. The diabetic group had significantly (p = 0.01) longer CTTs from P9 to Pl4, 5.0 msec as opposed to 4,2 msec for the nondiabetic group. The diabetic group also had significantly (p = 0.03) longer CTTs for the BAEP, 4.2 msec versus 4.0 msec for the nondiabetic group. Although the magnitude of the diagnostic group differences are small, the median nerve CV, SEP CTT, and BAEP CTT measures indicate that diabetic neuropathy is pervasive, occurring centrally, as well as peripherally, as early as young adulthood in juvenile onset, insulin dependent diabetics.
7

An Assessment of the Perception of Phonetic Ambiguities in 4 and 5 Year Olds

Carter, Elizabeth A. 01 January 1983 (has links)
The question of how humans clearly perceive speech, which is anything but clear when analyzed acoustically, has prompted researchers to look at the phenomenon of phonetic ambiguity. In adults, phonetic ambiguity perception has been shown to be aided by the listener using expectations due to the saliency (i.e., familiarity of the ambiguous word or phrase) and to pre-exposure (i.e., priming) to the items prior to testing. Priming makes the subject aware of the alternative (i.e., unfamiliar or rare) member of a phonetic ambiguity pair. In the present study, thirty-two 4 and 5 year olds were exposed to a tape containing familiar and rare ambiguity members and control items. One-half of them were primed. Results indicated that there was a strong beneficial effect of priming and saliency. The results of the present study were also compared with a previous adult study; this revealed a great deal of similarity between the two groups, implying 4 and 5 year olds can and do employ the same linguistic cues as adults.
8

Phonetic Ambiguity Perception in Reading Disabled and Non-disabled Children and Adolescents

Carter, Elizabeth A. 01 January 1986 (has links)
There are speculations that disabled readers may fail to correctly decode written words because they are insensitive to language's phonetic form. This insensitivity is presumed by some to be due to a speech perceptual deficit. The purpose of the current study was to assess differences between disabled and non-disabled adolescents and elementary school students in their perceptual accuracy in decoding phonetically ambiguous speech. The effects of two processing factors derived from previous research, priming and word form (e.g., Spencer & Carter, 1982), were also examined to assess how perceptual processes may differ between groups. Clinical evidence of some verbal problems persisting in adolescent disabled populations and evidence of compensatory differences between elementary and adolescent readers on earlier phonetic coding tasks prompted the inclusion of alI four age group by reading group combinations. Results reveal no reading group differences of either age grouping. The results are discussed in terms of design considerations, previous pertinent speech perception research, and similarity of responses to those of normal subjects in Spencer and Carter (1982) and Carter and Zoller (1983). With an examination of two dependent measures and a qualitative analysis of errors, no reading group differences were found. Therefore, it Is suggested that explanations involving speech perception may not appropriately address the problems of disabled readers with problems in word decoding.
9

Evaluation of an anaesthesia automated record keeping system : a human factors approach

TSE, Man Kei 14 August 2018 (has links)
Anaesthesia Information Management System (AIMS) is an automated record keeping system that imports and stores patient’s vital signs information from a physiological monitor in real-time. However, only a handful of studies have examined the effect of automated record keeping system on anaesthetists’ cognitive performance. Therefore, the current thesis aims to evaluate AIMS in terms of anaesthetists’ attitude (Study 1) and its effect on their cognitive performance (Study 2). Study 1, a questionnaire study examined anaesthetists’ trust and acceptance of AIMS. Forty-two anaesthetists at Tuen Mun Hospital (TMH) and Po Oi hospitals (POH) have completed a self-reported questionnaire. Results found that anaesthetists generally adopted a positive attitude toward AIMS. They exhibited a high level of trust and acceptance of AIMS. Also, they perceived AIMS as highly useful and relevant to their job. Study 2, a simulation study compared AIMS with manual record keeping on anaesthetists’ vigilance, situation awareness (SA) and mental workload. 20 anaesthetists at TMH were randomly assigned to two conditions: (1) AIMS and (2) Manual. Each participant received a 45-minute scenario in a full-scale simulation. Participants were asked to take over a case of general anaesthesia and perform record keeping. Results showed that AIMS did not impair anaesthetists’ vigilance and SA. In addition, it reduced anaesthetists’ mental workload and enabled them to spend less time on record keeping task. The current thesis provides an evaluation of AIMS by using a human factors approach. It contributes to the understanding on the effect of AIMS on anaesthetist’ in terms of attitude and cognitive performance. Based on the evaluation, we generate some recommendation for designers and hospitals to address the limitation of AIMS in interface designs and to increase anaesthetists’ acceptance of AIMS.
10

A study of authentic leadership adopting the job demands and resources approach in predicting work-related flow and job performance

WANG, Yiqing 01 January 2014 (has links)
The authentic leadership model posits that authentic leaders can foster personal development of their subordinates in order to produce better job outcomes. The current study has investigated authentic leadership using the job demands and resources (JD-R) approach to examine how leaders’ authenticity can empower employees in terms of resources-building (e.g. PsyCap, supervisor support); and to examine how these resources can offset negative stressors (e.g. work overload, emotional demands) so that employees may achieve a peak psychological state of flow (Bakker, 2005, 2008) and better job performances. To date, very few studies have tried to explain authentic leader behaviors in the JD-R model which is posited to be widely applicable to different work contexts, let alone studies of such type conducted in Chinese organizations. The current study consists of Study One and Study Two. The major purpose of Study One is to examine the reliability and validity of the authentic leadership and the work-related flow scale in Chinese organizational settings. The major purpose of Study Two is to test the hypotheses of the overall research model using Chinese working samples. Study One was conducted among Chinese workers in Shanghai (N=135). Confirmatory factor analysis was carried out for the reliability and validity of the authentic leadership and the work-related flow scale. Results confirmed that authentic leadership is best to be depicted as a second-order construct and the Cronbach’s alpha is .94 for the overall instrument. In addition, results also demonstrated that work-related flow has good reliability (Cronbach’s alpha is .96) and construct validity as a three-factor construct. Study Two aimed to test the proposed research model of the current study. 869 self-reported questionnaires were successfully collected from organizations in Shanghai. Performance was rated by employees’ supervisors to avoid common method bias. Structural equation modeling methods were adopted for data analyses. Results supported most of the hypotheses. Supervisor support (job resource) and PsyCap (personal resource) mediate the relationships between authentic leadership and two job outcomes (work-related flow, performance). Work overload and emotional demands moderate the positive indirect effects of authentic leadership on the job outcomes through supervisor support and PsyCap. This study has several contributions. First, it has provided a more comprehensive explanation of leadership and the consequent followers’ work behaviors via the JD-R approach. Second, it has linked the similarities in the JD-R model and the flow literature, which were previously studied in separate fields, demonstrating that high flow experience can be obtained only when resources become salient under high demands. Last but not least, the study has provided practical implications on leadership trainings and employee development programs, by pointing out several solutions of organizational improvement for the top management teams.

Page generated in 0.0925 seconds