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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.
1

Analysis of the behavioural effects of barley and sertraline in two in-vivo models of stress.Anti-depressant and anti-nociceptive effects of barley in mice and sertraline effects on anxiety in the offspring of prenatally-stressed rats

Al-Shehri, M.A.S. January 2015 (has links)
To prove the post-natal depression model, the antidepressant sertraline, was assessed in rat mothers (n=14) divided into Prenatally Stressed (PS) and Non-Stressed (NS) groups. The data failed to support the hypothesis that ‘the progeny of 10mg of sertraline-treated PS mothers displayed less anxiety than the progeny of vehicle-treated PS mothers’. The forced swim test (FST) was used to examine depressive-like behaviour in mice. Barley successfully increased mobility in mice exposed to the FST. Barley was antidepressant at low doses (0.8g/kg and upwards) if used subchronic; and at high doses(6.4g/kg and 12.8g/kg) if used acutely;(n=113,56acute,57 subchronic- treated). Barley (6.4g/kg) was also able to alleviate the depressive-behaviour in mice induced by the Reserpine Test (n=114, 58 reserpinised, 56 non-reserpinised) and Social ‘Defeat’ Test (n=24, 8 vehicle undefeated, 8 barley defeated, 8 vehicle defeated mice). To confirm that the anti-depressant effects of barley(6.4g/kg) were not simply due to increased locomotor activity in the FST, an Open Field Test(OFT) was undertaken (n=14,7 vehicle, 7 barley). Barley had no effect on locomotor activity and also caused no significant changes in weight (n=16, 8vehicle, 8 barley). In mice,Barley(6.4g/kg) significantly delayed the tremorogenic effects of Physostigmine (n=18, 6 control,6 Physostigmine, 6 Physostigmine with barley); reduced bradykinesia induced by reserpine (n=18,6 control, 6 vehicle, 6 barley treated);and was analgesic in nociception tests (n =20, 5 control, 5 barley, 5 pain, 5 pain with barley). Overall, barley was seen to have many useful properties, though its effect in PND remains to be assessed. / Saudi Cultural Bureau in London; Medical Services Department of the Ministry of Interior in Riyadh, Saudi Arabia. / The full text of this thesis is embargoed indefinitely.
2

Analysis of the behavioural effects of barley and sertraline in two in-vivo models of stress : anti-depressant and anti-nociceptive effects of barley in mice and sertraline effects on anxiety in the offspring of prenatally-stressed rats

Al-Shehri, M. A. S. January 2015 (has links)
To prove the post-natal depression model, the antidepressant sertraline, was assessed in rat mothers (n=14) divided into Prenatally Stressed (PS) and Non-Stressed (NS) groups. The data failed to support the hypothesis that ‘the progeny of 10mg of sertraline-treated PS mothers displayed less anxiety than the progeny of vehicle-treated PS mothers’. The forced swim test (FST) was used to examine depressive-like behaviour in mice. Barley successfully increased mobility in mice exposed to the FST. Barley was antidepressant at low doses (0.8g/kg and upwards) if used subchronic; and at high doses(6.4g/kg and 12.8g/kg) if used acutely;(n=113,56acute,57 subchronic- treated). Barley (6.4g/kg) was also able to alleviate the depressive-behaviour in mice induced by the Reserpine Test (n=114, 58 reserpinised, 56 non-reserpinised) and Social ‘Defeat’ Test (n=24, 8 vehicle undefeated, 8 barley defeated, 8 vehicle defeated mice). To confirm that the anti-depressant effects of barley(6.4g/kg) were not simply due to increased locomotor activity in the FST, an Open Field Test(OFT) was undertaken (n=14,7 vehicle, 7 barley). Barley had no effect on locomotor activity and also caused no significant changes in weight (n=16, 8vehicle, 8 barley). In mice,Barley(6.4g/kg) significantly delayed the tremorogenic effects of Physostigmine (n=18, 6 control,6 Physostigmine, 6 Physostigmine with barley); reduced bradykinesia induced by reserpine (n=18,6 control, 6 vehicle, 6 barley treated);and was analgesic in nociception tests (n =20, 5 control, 5 barley, 5 pain, 5 pain with barley). Overall, barley was seen to have many useful properties, though its effect in PND remains to be assessed.
3

A duration dependent model of the effects of job stress on the speed of seeking treatment for health problems

Sokoloff, Robert Michael January 1994 (has links)
No description available.
4

Evaluating the Effects of Heat Stress on the Cardiovascular System and Psychophysical Response of Firefighters

Musolin, Kristin M. 20 September 2011 (has links)
No description available.
5

Using the Biopsychosocial Model of Threat and Challenge to Understand the Occurrence of Placebo Effects

Caplandies, Fawn C. January 2015 (has links)
No description available.
6

Generational Effects of Bisphenol A on Growth and Stress Performance in Rainbow Trout

Birceanu, Oana 25 June 2015 (has links)
The aquatic environment is severely impacted by xenobiotics that are released due to anthropogenic activities, threatening ecosystem health. Some of these contaminants accumulate in lipophilic fish tissues and are maternally transferred to developing offspring, affecting their growth and performance. However, knowledge about the long-term and generational impacts associated with maternal transfer of contaminants is limited in fish. In this thesis, the hypothesis tested was that maternal transfer of bisphenol A (BPA) leads to disruption in the developmental programing of growth and stress axes functioning in rainbow trout (Oncorhynchus mykiss), and that these changes are passed on to the next generation. This was tested by exposing oocytes to either control (vehicle; <0.01% ethanol) 0.3, 3.0, and 30.0 mg l-1 BPA in ovarian fluid for 3 h, prior to fertilization, to mimic maternal transfer. This led to the accumulation of 0, 0.8, 4.4 and 41.3 ng BPA embryo-1. Oocytes were fertilized with milt from clean males, and offspring growth, development and stress performances were assessed in a clean environment for a year (F1 generation). For F2 generation, oocytes collected from F1 females, raised from the different BPA accumulated eggs, were fertilized with milt from clean males and raised in a clean environment for one year as described for F1 generation. The accumulated BPA in eggs was quickly cleared and it was no longer detected in the F1 embryos at hatch. BPA exposure reduced specific growth rate and increased food conversion ratio in larvae reared from BPA-laden oocytes. Moreover, BPA-exposed fish had an altered cortisol developmental profile and a delay in stress axis maturation. In addition, the mRNA abundance of genes involved in somatotropic [insulin-like growth factor (IGF) -1; IGF-2; IGF receptor b (IGF-1rb)] and stress axes functioning [steroidogenic acute regulatory protein (StAR); cytochrome P450 side chain cleavage (P450scc)] were altered. Also, changes in thyroid signaling [thyroid receptor (TR) mRNA levels] and cortisol signaling [glucocorticoid receptor (GR) protein expression] were disrupted temporally during development. These results demonstrate that BPA accumulation in eggs, mimicking maternal transfer, impacts growth and development, and delays stress axis maturation via non-reproductive endocrine disrupting routes in trout. Some of the BPA changes seen in F1 generation also persisted in the F2 generation. For instance, ancestral exposure to BPA led to reduced growth and whole body glycogen content prior to feeding in the F2 fish. The developmental transcript profile of growth hormone-1and -2, IGF-1 and -2 and IGF-1rb, along with whole body cortisol levels were impacted by ancestral exposure to BPA. Moreover, a delay in cortisol dynamics post-stress was noted in the F2 fish of BPA exposure lineage. Our results show that ancestral exposure to BPA leads to effects on growth and stress performance in rainbow trout, but the mechanism is not known. To further investigate the long-term effect of BPA accumulation in eggs on stress performances, F1 and F2 juvenile fish were subjected to an acute stressor. Also, head kidney tissues from these juvenile fish were subjected to adrenocorticotrophic hormone (ACTH) stimulation in vitro to assess cortisol production capacity. BPA accumulation in eggs led to a reduced acute handling stressor-induced plasma cortisol response in trout from the F1 and F2 (only high BPA group) generations. Also, BPA exposure had a pronounced impact on acute handling stressor-mediated plasma glucose (only F2 generation) and lactate levels, indicative of a metabolic disturbance. BPA exposure (only the 4.4 ng group) did affect unstimulated but not stimulated [ACTH or 8-bromo-cyclic AMP (8-B-cAMP)] cortisol production from head kidney slices of juvenile fish from F1 generation. In the F2 generation, there was an increase in ACTH-stimulated cortisol production only from the high BPA-exposed group. Overall, BPA in eggs disrupts long-term cortisol and metabolic stress performances in rainbow trout. While the impaired plasma cortisol stress performance was dose-related in the F1, the effect was apparent only for high BPA group in the F2 generation, suggesting that the generational effects on cortisol stress axis functioning may be concentration-dependent. A metabolomics approach further confirmed multigenerational effects associated with BPA accumulation in eggs. Analysis of the metabolome profile at hatch and prior to first feed, using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS), revealed a BPA-mediated metabolic disruption, including changes in pathways involved in carbohydrate, lipid and amino sugar metabolism, and amino acid metabolism and synthesis. Pathways involved in citric acid cycle and alanine, aspartate and glutamate metabolism were altered in both generations, suggesting that these pathways have the potential to be markers with predictive value for multigenerational effects of BPA in fish. Altogether, the study provides novel insights on the impact of BPA on rainbow trout metabolome at hatch and first feed. The results suggest that pathways involved in energy metabolism are targets for BPA impact and should be investigated as potential markers for BPA toxicity. Overall, BPA accumulation in oocytes induces long-term delays in growth and stress axis maturation in F1 generations fish, and these effects persist in the F2 generation. The developmental profiles of key genes of the somatotropic and HPI axes were altered by BPA, along with whole body composition, suggesting that BPA exposure leads to a metabolic disturbance in fish, resulting in reduced growth. Additionally, the altered plasma cortisol response to acute stress in F1 and F2 juveniles provides evidence for multigenerational effects of BPA on stress axis functioning. The current study proposes that BPA-induced epigenetic modifications during early development may be playing a key role in the generational effects on growth and stress axes disruption in trout. The finding that the growth and developmental changes to BPA exposure also corresponds with endocrine and metabolome changes in multiple generations in trout is novel, and underscores the necessity to develop new risk assessments tools for chemicals that are maternally transferred in fish.
7

Estrés y burnout docente: conceptos, causas y efectos / Estrés y burnout docente: conceptos, causas y efectos

Zavala Zavala, José 10 April 2018 (has links)
In this article the concepts of stress (eustress and distress) and stress coping arereviewed under a transactional perspective mainly, and it is also described the burnoutor syndrome of professional wearing as consequence of the chronic stress. Itis also offered a series of statisticals related to Latin-American teachers’ perceptionsof stress and health conditions, and there is indeed the shadow of a doubt of thepossible suffering of burnout. The stress has direct effects in the physical and psychologicalwell being of the teacher, and simultaneously an impact in the personallife and his/her performance of the educational organization. / En este artículo se revisan los conceptos de estrés (eustrés y distrés) y afrontamientobajo una perspectiva transaccional principalmente, y se describe el llamado síndromede desgaste profesional o burnout como consecuencia del estrés crónico.Se ofrecen una serie de estadísticos relacionados tanto con la percepción del estrésy como la salud en muestras latinoamericanas de docentes de educación básica,y por ende, se vislumbra la posible presencia de burnout. El estrés tiene efectosdirectos en la salud física y psicológica del docente, y a la vez un impacto en suvida personal y desempeño de la organización.
8

Heart Rate Variability in Patients with Coronary Artery Disease: Reproducibility, Circadian Variability and the Effects of Stress / The Effects of a Stress on Heart Rate Variability in Patients with Coronary Artery Disease

O'Leary, Deborah 08 1900 (has links)
The purpose of this study was to assess heart rate variability (HRV) in patients with coronary artery disease (CAD): reproducibility, circadian variability and the effects of stress (coronary angiogram). Sixty-one patients who had a coronary angiogram underwent 48-hour Holter monitoring during a period of high stress beginning 4-hours post-angiography (Day 1 and 2), and again two weeks later during a period of low stress (Day 3 and 4); both 24-hour time domain and power spectral measures were computed. To determine reproducibility, intraclass correlation coefficients were calculated for both time and frequency domain indices on Days 3 and 4. The intraclass correlation coefficient for the standard deviation of normal RR-intervals over 24-hours (SDNN) was 0.91, while the standard deviation of the mean of all 5-minute segments of normal RR-intervals for 24-hours (SDANN) was 0.85. The most reproducible time domain measure was pNN50 (defined as the percentage of differences between adjacent normal RR-intervals that are greater than 50 ms computed over 24-hours) with an intraclass correlation coefficient of 0.95. As for the frequency domain measures including low frequency (LF) area, high frequency (HF) area, low frequency to high frequency area ratio (LF:HF area), LF central frequency (cf), and total area (TA), intraclass correlations were found to be the best at 0300-hours and the worst at 1500-hours. Circadian pattern was determined on Day 4 of Holter monitoring. A main effect for time was found for heart rate (HR), LF area, HF area, and TA of the power spectra. Over a 24-hour period, HR, LF area, HF area and TA were the lowest at 0300-hours compared to all other times. There was also a main effect for myocardial infarction (MI) for the frequency domain indices LF area, HF area, LF:HF area ratio, and LFcf. Low frequency area and LF:HF area ratio were significantly elevated (both p<0.05), while both HF area (p<0.05) and LFcf (p<0.01) were reduced in patients with a prior Ml compared to those with no MI. As well, a significant interaction between time of day and Ml, and time of day and beta-blocker therapy was observed. Patients with coronary artery disease and a prior Ml demonstrated a reduced circadian pattern over 24-hours for HR. Likewise, the circadian pattern of HR for those on beta-blockers was also attenuated. The effects of stress was determined by comparing Day 1 to Day 4 of ambulatory Holter monitoring. The time domain measure SDNN was found to be significantly reduced during Day 1 (mean ± SEM; 111.67 ± 6.13 ms) compared to Day 4 (121.54 ± 6.94 ms; p<0.05). Patients with normal left ventricular function (LVF) showed a significant increase from Day 1 to 4 for both SDNN (p<0.01) and SDANN (p<0.05). In contrast, those with LV dysfunction had an attenuated response. Similarly, those CAD patients on beta-blockers demonstrated a significant increase for the time domain measure SDNN (p<0.05), unlike those not on beta-blockers. In the frequency domain, LF:HF area was significantly greater on Day 1 (1.74 ± 0.09) compared to Day 4 (1.64 ± 0.09; p<0.05). These findings suggest that HRV measures are reproducible, that a circadian pattern for HRV exists in patients with CAD, and that stress induced by an invasive procedure such as a coronary angiogram enhances sympathetic input to the SA node in the heart and thereby alters the sympathovagal balance, which is restored two weeks later. / Thesis / Master of Science (MSc)
9

Environmentálně-psychologická východiska výchovy v přírodě / The Basis of Environmental Psychology for Outdoor Education (The Influence of Nature on Mental and Social Well-Being)

VRBOVÁ, Zuzana January 2012 (has links)
The work deals with theoretical research of basis of Environmental Psychology for Outdoor Education. It answers two questions ? why in the conceptions of Outdoor Education is nature the preferred environment and what are the benefits of nature for physical, mental and social health. The answers to theses questions are in the work described through theories of environmental preference and restorative effects of nature. There are three major sections of the work. The first part discusses the basis, principles and contents of Environmental Psychology and Outdoor Education, the core terminology of the work, and the nodal points of Environmental Psyhcology and the theory of Outdoor Education. Second part describes those theories and concepts of Environmental Psychology which are related to the primary and subsidiary research questions. The third part evaluates the impacts and relevance of environmental-psychological knowledge on concepts of Outdoor Education.

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