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1
Cesaretti, Juan Manuel. „Mechanical stress and stress compensation in Hall sensors“. Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28202.
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2
Eakes, Donald Joseph. „Moisture stress conditioning, potassium nutrition, and tolerance of Salvia splendens 'Bonfire' to moisture stress“. Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54350.
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The objective of this study was to determine the leaf water relations, gas exchange, and growth of the bedding plant salvia Salvia splendens 'Bonfire‘ as influenced by moisture stress conditioning (MSC - exposing plants to 4 sublethal dry-down cycles) and potassium (K) nutrition. Plants were fertilized with one of six K rates: 25, 75, 150, 300, 450, and 600 ppm as KCl in experiment one. Seven weeks after seeding plants were subjected to MSC. MSC and increasing K rate resulted in osmotic adjustment and increased cellular turgor potentials. Foliar K content increased as osmotic potentials decreased due to treatment. Although there was no interaction, MSC and high K rates both reduced transpiration (E), leaf conductance (g₁), and daily gravimetric water loss during well watered conditions. Greatest shoot dry weight occurred for plants grown with 300 ppm K and no-MSC.
Gas exchange of salvia as influenced by MSC during the onset of moisture stress was determined in experiment two. On day one following final irrigation, MSC plants had lower mid-day E, g₁, hourly gravimetric water loss per unit leaf area, and net photosynthesis (Pn) compared to controls, despite no differences in leaf water potential (ψ₁). Percentage of stomatal inhibition of Pn (SI) was greater for MSC plants than controls with no differences in mesophyllic resistance to CO₂ (rm). On day two, MSC plants had greater Pn, E, g₁, and hourly gravimetric water loss per unit leaf area, while SI and rm were lower than controls. MSC plants maintained positive Pn rates and turgor to lower ψ₁ than control plants. Water use efficiency (WUE) estimates for MSC plants were greater than for controls.
Salvia plants were fertilized with 75, 300, or 600 ppm K to determine the influence of K rate on gas exchange during the onset of moisture stress in a third experiment. On day one following final irrigation, plants grown with K rates of 300 and 600 ppm had lower E, g₁, hourly gravimetric water loss per unit leaf area, and Pn compared to 75 ppm K plants. On day two, 600 ppm K plants had greater Pn, E, and g₁ as the experiment was terminated compared to plants grown with 75 ppm K, although ψ₁ was similar. Potassium rate had little affect on WUE.Ph. D.
3
Dölle, Michael. „Field effect transistor based CMOS stress sensors /“. Tönning ; Lübeck Marburg : Der Andere Verlag, 2006. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016086105&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Maliphant, Paula. „The effect of pesticide stress on diatoms“. Thesis, University of Hertfordshire, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309720.
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5
Chung, Samwon. „The effect of internal stress on diffusion“. Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058210791.
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6
Clune, Timothy Scott. „The effect of aluminium stress on canola“. Phd thesis, Department of Agricultural Chemistry and Soil Sciences, 1997. http://hdl.handle.net/2123/11809.
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7
MACHADO, VERONICA MIQUELIN. „EFFECT OF ELASTIC-PLASTIC STRESS IN THE DEFECT TOLERANCE UNDER STRESS CORROSION CRACKING“. PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33679@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Corrosão sob tensão (SCC), que consiste na iniciação e propagação de trincas devido ao efeito combinado de tensões mecânicas e o ambiente corrosivo, é um dano potencial para estruturas e componentes. Além do mais, SCC pode ser explicado por diferentes mecanismos dependendo do par material ambiente corrosivo considerado, o que dificulta o uso de um modelo geral para predizer o comportamento de trincas em SCC. Sendo assim, projetos frequentemente utilizam um critério conservativo que desqualifica materiais susceptíveis à SCC sem analisar de maneira apropriada a influência dos campos de tensão que a induzem. O objetivo deste trabalho é avaliar o efeito de tensões elastoplásticas na corrosão sob tensão. Esta abordagem mecânica considera que todos os efeitos corrosivos envolvidos na corrosão sob tensão podem ser apropriadamente quantificados pelas tradicionais resistências do material à iniciação e propagação de trincas para um ambiente corrosivo específico. Corpos de prova de flexão em Alumínio fragilizados por Gálio líquido serão utilizados para prever o efeito de tensões residuais induzidas por deformações plásticas na iniciação de trincas por corrosão sob tensão. Além disso, uma análise quantitativa baseada no comportamento de trincas não propagantes a partir de entalhes será usada para estimar a tensão necessária para iniciar e propagar trincas em corpos de prova entalhados em aço AISI 4140 sujeitos à corrosão por sulfeto de hidrogênio em ambiente aquoso. O comportamento de trincas curtas e a carga máxima suportada pelos corpos de prova entalhados são analisadas considerando campos de tensões lineares elástico e elastoplásticos através do modelo proposto que será validado através de dados experimentais.
Stress Corrosion Cracking (SCC), which consist in the initiation and propagation of cracks due to the combined attack of mechanical stresses and a corrosive environment is a potential danger for structures and components. Moreover, SCC can be explained by different mechanisms depending on the metal environmental pair, what makes difficult to create a generalized analytical approach to predict the crack behavior in SCC. Therefore, projects often use an over-conservative design criteria that disqualify a material susceptible to SCC without properly evaluate the influence of the stress fields that drive them. The aim of this work is to evaluate the effect of elastic-plastic stress in SCC. This mechanical approach assumes that all chemical effects involved in SCC problems can be appositely described and quantified by traditional material resistances to crack initiation and propagation at under specific environment. Aluminum bending specimens in Gallium environment are used to predict the effect of the residual stress induced by plastic deformation in the crack initiation under SCC conditions. Furthermore, a quantitative analysis based on the non-propagating crack behavior departing from notch tips are used to calculate the necessary stress to initiate and propagate SCC in AISI 4140 steel notched specimens under aqueous hydrogen sulfide environment. The non-propagating crack behavior and the maximum load supported by notched specimens are analyzed under linear elastic and elastic-plastic stress field through the proposed model that will be validated by experimental data.
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Iyer, Venkatramani S. „Effect of residual stress gradients in austenitic stainless steels on stress corrosion cracking“. Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/42119.
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The effect of the residual stresses developed during simulated weld heat affected zone in
austenitic stainless steel specimen on the stress corrosion cracking susceptibility was studied.
Residual stresses was measured using X-ray diffraction technique. Boiling Magnesium
Chloride was used as corrosive environment. Compressive stresses developed in the HAZ of
the specimen and in regions away from the HAZ stress free values were obtained. The magnitude
of the stress gradient decreased as the peak temperature attained during simulated
welding decreased. Transgranular cracks were observed in the compressive stress gradient
region and time to cracking decreased with increasing stress gradient. Higher nickel content
alloys took longer to crack as opposed to lower nickel content alloys at approximately the
same stress gradient.
Master of Science
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Sorooshzadeh, Ali. „Environmental stress and calcium nutrition during the seed-filling stage of soybean“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0015/NQ44594.pdf.
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Martin, David E. „The effect of heat stress on excess post exercise oxygen consumption“. Virtual Press, 1992. http://liblink.bsu.edu/uhtbin/catkey/834623.
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While a great deal of research has been directed towards the phenomena of excess post exercise oxygen consumption (EPOC), the effect of thermal stress on EPOC is not well defined. To assess the effect of heat stress on EPOC, seven healthy, active subjects (4 female, 3 male; 23.9 ± 2.0 years of age) performed 4 trials: one control (quiet rest) and one exercise (45 minutes of cycling at 65% VO2max workload) trial in moderate (23° C, 50% humidity) and hot (35° C, 50% humidity) environments. Oxygen consumption (V02), heart rate (HR) and rectal temperature (RT) were assessed pre, during and post control or exercise. Subjects were monitored until post exercise VO2 had returned to within ±2% of baseline. EPOC was determined by subtracting baseline VO2 from total V02 during the post exercise period. During the first 15 minutes (acute) post exercise, a significant EPOC (p = 0.0019) was seen in both exercise conditions over both control conditions. During the slow phase (> 15 minutes post exercise to baseline), there was no significant difference between the hot control (HC), moderate exercise (ME), or hot exercise (HE) EPOC. Total time post exercise until baseline was achieved was 35, 44, and 51 minutes for HC, ME, and HE respectively. HR was significantly elevated in both exercise conditions. During the acute post exercise period, HR in HE was elevated above MC, ME and HC (p < 0.05). RT was elevated in both exercise conditions during and post exercise. The present data indicate that heat stress does not have a significant effect on the magnitude or duration of EPOC.School of Physical Education
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Jalušková, Radka. „Vyhodnocování, zvládání a snižování stresu“. Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2011. http://www.nusl.cz/ntk/nusl-223249.
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The Master´s Thesis „Stress evaluation, coping and reduction” deals with analyzing stress in students, ordinary workers and top managers. The theoretical part analyzes stress, effects of stress, its impact on human health, his work / study results and overall his life. The practical part is concerned with the influence of stress on students, ordinary workers and top managers, using a questionnaire. On the basis of the analysis is specified what causes stress for the various groups, how most respondents solve the stress. The conclusion of the work includes the proposal of effective coping and stress reduction for each group of respondents.
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Barsoum, Imad. „The effect of stress state in ductile failure“. Doctoral thesis, Stockholm : Hållfasthetslära, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4667.
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Bogart, Robert William. „The effect of stress on global cerebral ischemia“. Connect to resource, 2008. http://hdl.handle.net/1811/32235.
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14
Poirier, Patrick. „Effect of chronic stress on prefrontal cortical function“. Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86861.
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The prefrontal cortex (PFC) is a brain region thought to mediate cognitive functions such as working memory. Chronic stress has been shown to reduce working memory. In this thesis study, the effect of chronic stress on PFC functions was assessed in adult rats.First, contrary to previous evidences, chronic stress induces working memory performance alterations differentially in two populations of rats. One group displayed a decrease of performance only at 30 second delay, while the other had a decrease and increase at 0 and 30 seconds respectively.
Then, the effect of chronic stress on synaptic plasticity induction in the hippocampus-PFC network was investigated. High-frequency tetanic stimulation (HFS) of the dorsal hippocampus that induced long-term potentiation (LTP) in the prelimbic and infralimbic cortex in normal conditions was unable to induce LTP after chronic stress in the infralimbic cortex, whereas long-term depression (LTD) instead of LTP was induced in the prelimbic cortex.
Given that synaptic plasticity has been shown to depend on NMDA receptors in the PFC, NMDA subunit expressions before and after chronic stress was examined. There was a decrease of NR1 subunits expression in the prelimbic, but not infralimbic cortex. In contrast, the NR2A/NR2B ratio was increased in the infralimbic, but not prelimbic cortex. These results suggest that chronic stress disrupts PFC functions through dynamic modulation of distinct neural networks within the PFC.
Le cortex préfrontal (PFC) est une région du cerveau qui contrôle les fonctions cognitives comme la mémoire de travail. Dans cette thèse, l'effet du stress chronique sur des fonctions du PFC a été analysé chez des rats adultes.
Premièrement, les performances de la mémoire de travail ont été mesurées avant et après exposition au stress chronique. Nous avons constaté que le stress chronique induit des changements de performances de la mémoire de travail différemment selon deux populations de rats. Une des populations a démontré une diminution de performance seulement à 30 secondes de délai. Au contraire, l'autre a démontré une diminution de performance à 0 seconde et une amélioration de performance à 30 secondes.
En plus, nous avons évalué l'effet du stress chronique sur l'induction de la plasticité synaptique dans le réseau reliant l'hippocampe au PFC. Dans les conditions initiales, une stimulation tétanique à haute fréquence (HFS) dans l'hippocampe dorsal provoquait une potentialisation à long terme (LTP) dans le cortex prélimbique et infralimbique Or après exposition au stress chronique, une stimulation tétanique à haute fréquence n'a pas entraîné de potentialisation à long terme dans le cortex infralimbique. De plus, une exposition au stress chronique a provoqué l'apparition dans le cortex prélimbique d'une dépression à long terme (LTD) plutôt qu'une potentialisation à long terme.
Étant donné que la plasticité synaptique dépend des récepteurs de NMDA dans le PFC, nous avons examiné l'expression de sous-unité de NMDA avant et après exposition au stress chronique. En accord avec les changements synaptiques distincts de plasticité entre le cortex prélimbique et infralimbique après exposition au stress chronique, nous avons observé que l'expression de la sous-unité NR1 a diminué dans le prélimbique, mais non dans l'infralimbique. En revanche, le ratio de NR2A/NR2B a augmenté dans le cortex infralimbique, mais non dans le prélimbique. Ces résultats suggèrent que le stress chronique perturbe les fonctions du PFC par la modulation dynamique des réseaux distincts neurologiques dans le PFC.
15
Picton, S. „The effect of heat-stress on tomato ripening“. Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233614.
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Mathers, John F. „The effect of stress on golf putting performance“. Thesis, University of Strathclyde, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431793.
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Yeh, Lestter. „The Effect of Stress Coping Techniques in Sports“. Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1240.
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The first part of this literature review goes over the biological and psychological aspects of stress. The cause of stress can be linked back to a primitive instinct known as “fight or flight.” The “fight or flight” instinct is triggered by several chemical reactions in the body starting from a signal from the amygdala to the sympathetic nervous system. Stress can also be categorized into internal and external stress. Further research links stress to sports. Many studies show that stress coping techniques such as meditation, self-talk, rituals, etc. are beneficial to athletes during competition. Suggested avenues of further research are to develop a standardized way to incorporate practicing stress coping techniques into a younger athlete’s routine, discover whether the same stress coping techniques can be used throughout all sports, and whether certain stress coping techniques will benefit people of different personality types equally. Keywords: Stress, Coping, Sports, Psychology, Athlete
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Kumsta, Caroline. „The effect of oxidative stress on C. elegans“. kostenfrei, 2008. http://mediatum2.ub.tum.de/doc/678556/678556.pdf.
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Hoskin, Robert. „The effect of psychological stress on auditory perception“. Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6193/.
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Psychological stress appears to precede instances of auditory hallucinations in those vulnerable to them. This suggests that psychological stress acts on the auditory perceptual system in such a way as to encourage the generation of false percepts. This thesis investigated the impact of psychological stress on the perception of emotionally neutral sounds with the aim of identifying a potential mechanism to explain the influence of stress on the occurrence of auditory hallucinations. Two interconnected hypotheses, arising from the theory that stress reduces attentional control and therefore the ability to inhibit distracting information, were tested. An auditory signal detection task was created to test whether stress would reduce the ability of the auditory-perceptual mechanism to accurately detect signals. Instead of reducing discrimination ability, stress was found to bias responding towards reporting a signal in highly anxious individuals. A number of passive oddball tasks were designed to test the hypothesis that stress would increase the distraction caused by emotionally neutral sounds. Once again this hypothesis was largely refuted, with stress appearing to reduce, rather than increase, the impact of distracting auditory information on task performance. On the basis of these findings a revised model of how stress may encourage auditory hallucinations was proposed. This model suggests that, through a strengthening of selective attention, stress may mal-adaptively bias auditory perception towards misinterpreting internal signals as external. Further research proposals, designed to test the predictions of this model, are suggested.
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Bakr, Mahmoud. „Parathyroid hormone effect on facilitating stress fracture repair“. Thesis, Griffith University, 2019. http://hdl.handle.net/10072/389571.
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Stress fractures (SFx) result from repetitive cyclical loading of bone. They are frequent athletic injuries and underlie atypical femoral fractures following long-term bisphosphonate (BP) therapy. Parathyroid hormone (PTH) and BPs, including Alendronate (ALN), have opposing effects on bone dynamics. ALN is an antiresorptive agent that decreases bone turnover, and with prolonged doses of BP the healing of SFxs is delayed. The extent to which intermittent PTH (iPTH) remains effective in the treatment of SFx in the presence of an ongoing BP treatment has not been tested. Starting 24 hours after SFx induction, the effect of a single PTH injection, and daily iPTH injections for 14 days, on the healing of SFx in the rat ulna was investigated. SFx was induced in 330 female Wistar rats (300 +- 15 g) during a single loading session. In the single PTH injection experiment, rats were divided into two groups (n=60). A single PTH (8 μg/100g) or vehicle (VEH) saline injection was administered 24 hours after loading. Ulnae were examined 1, 2, 6 or 10 weeks following SFx.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
Griffith Health
Full Text
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Le, Fevre Ruth Elizabeth. „Phytate and plant stress responses“. Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708218.
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Followell, Timothy B. „Effect of Dental Treatment on Parental Stress as Measured by the Parenting Stress Index“. The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276567183.
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Brattos, Alexandra. „The Effect of Stress Presentation Mode on Stress Acquisition Among Advanced Learners of Russian“. BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3140.
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The purpose of this research was to test the effect of stress presentation mode on stress acquisition of advanced learners of Russian. The study attempted to determine if advanced learners of Russian are able to place stress more correctly on words in specific texts after receiving various treatments or receiving no treatment. Participants were Brigham Young University students studying Russian as a second language at the third-year level or higher. They were randomly assigned into three groups: a group that received no treatment, a treatment group that read words with graphically marked stress, and a treatment group that heard texts read by a native speaker. All participants completed a pretest, a treatment (in the second and third groups), and a posttest. The pretest and the posttest consisted of a reading task: the participants read 12 sentences taken from 12 different texts. The same words from the texts were used in the treatment to expose the participants to the sentences again in order to determine if the treatment made a difference in the acquisition of correct stress. The treatment was different for each group. Group 1 (A) read texts marked with stress, Group 2 (B) read the same texts but without stress marked; rather, they heard a native speaker of Russian read the texts on a recording, and Group 3 (C) read the same texts but without stress marked graphically or hearing a native speaker. The results of the research reject the hypothesis that aural presentation of stress as opposed to a visual only presentation leads to improved acquisition of stress. However, based on the analyses of the data, overall findings rendered some interesting and unexpected results and observations. First, although the treatment for group A appears to be more effective than that for groups B and C, all groups showed improvement after completing the treatment. This strongly suggests that reading, whatever form it takes, can be a useful tool in facilitating control of stress. Second, group A had more participants that fell into the "fast" reading category, and fast readers scored significantly higher than slow or medium speed readers. This suggests that the faster one reads the better one controls stress, or the better one controls stress the faster one reads.
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Nourifard, Nazanin. „Effect of Stress Magnitude and Stress Rate on Elastic Properties of the Reservoir Rocks“. Thesis, Curtin University, 2019. http://hdl.handle.net/20.500.11937/77386.
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We studied the effect of stress magnitude and stress rate on elastic properties of the reservoir rocks. We designed and developed experiments to study: (i) the dynamic and static elastic moduli of reservoir rocks, (ii) quantifying the effects of wave’s amplitude on the longitudinal and transverse velocities in porous media, and (iii) anisotropy of sandstone subjected to stress in dry and saturated statuses.
25
Cummins, Robert A. „The effect of organizational structure and demographics on administrative stress“. Theological Research Exchange Network (TREN), 1987. http://www.tren.com.
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Alm, David Michael. „Comparison and interaction of heat and salt stress in cultured tobacco cells“. Virtual Press, 1986. http://liblink.bsu.edu/uhtbin/catkey/445616.
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Cultured tobacco cells (Nicotiana tabacum L., cv Wisconsin-38) were subjected to temporary sub-lethal heat and salt shock treatments to determine the effects of these treatments on various physiological parameters after subsequent lethal heat or salt stresses. Tobacco cells developed a tolerance to a non-permissive temperature stress (54C for 14 min) when pretreated with heat shock of 38C for 2h but not when pretreated at 42C for 2h. Cells pretreated at 38 (2h) exhibited less than 30% normal growth when the 54C stress came immediately after the 38C treatment. Tolerance to the 54C stress developed with increased interval between shock and stress with cells exhibiting 95% normal regrowth when the 54C stress was administered 8h after the 38C shock. The developement of heat tolerance was inhibited if heat shock was done in the presence of a non-injuring level of EGTA (.0.5mM). Cells treated with EGTA during heat shock grew normally at 23C but not after a 54C heat stress. EDTA (0.5mM) had little effect on the acquisition of tolerance to heat stress.Wisconsin-38 cells developed a tolerance to a non-permissive salt stress (2% NaCl for 16h) when pretreated at a lower salt level (1.2% NaCl) for 3h. Cells heat shocked at 38C exhibited increased tolerance of the lethal salt stress up to 8h. Conversely, cells heat shocked at 42C exhibited immediate tolerance to lethal salt stress and this tolerance decayed over eight hours. The heat shock-induced acquisition of salt tolerance was inhibited by both EGTA and EDTA.Proteins synthesized during heat and salt stress treatments were labeled with [35S]-methionine and/or [3H]-leucine and separated using Sodium dodecylsulfate polyacrylamide gel electrophoresis. Fluorographic analysis of the gels indicate that a number of proteins are produced in response to heat shock. Similar analysis of proteins from salt shocked cells indicates that no salt shock proteins are produced in response to a brief low-level sodium chloride shock.
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Kalifa, Ali. „Salt stress, and phosphorus absorption by potato plants cv. 'Russet Burbank'“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29727.pdf.
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Su, Dan. „Microcrack damage and its effect on stress wave propagation“. Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 114 p, 2009. http://proquest.umi.com/pqdweb?did=1654487641&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Lee, Suhyun. „Long-term metabolic effects of stress and antidepressants : a novel paradigm of antidepressant-induced weight gain in the post-stress acclimation period“. Phd thesis, Canberra, ACT : The Australian National University, 2014. http://hdl.handle.net/1885/125029.
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Despite the frequent use of antidepressants and the high incidence of obesity in Australia and many other developed countries, the relationship between major depressive disorder, obesity and antidepressant use remains complex. The association between antidepressant use and body weight gain has been widely reported. However, the pathophysiological mechanisms of this association are still poorly understood. In this thesis, an animal paradigm that addresses the "paradoxical" weight loss of rodents during antidepressant treatment was developed. The paradigm referred here as the SAD model and consisting of short-term exposure to recurrent restraint stress (RRS) and antidepressant treatment for two weeks, followed by long-term high-fat diet was evaluated in male Sprague-Dawley rats for 296 days. The phenotypic characteristics of the SAD model were compared to the diet-induced obesity (DIO) model, a model of obesity solely induced by high-fat diet. Immediately after the RRS period, groups of animals that underwent RRS had significantly lower body weight in comparison to the DIO group. The rate of weight gain during the catch up growth phase was significantly greater in the SAD model than in the DIO model. During the post-restraint period, the SAD model of fluoxetine-treated group became heavier than the DIO model, however this happened only in the animals in the upper half of body weight gain, i.e. the obesity prone group. Body weight gain in the SAD model in comparison to the DIO model was referred as "SAD-induced weight gain". The SAD model of fluoxetine-treated group had significantly greater body length and enhanced morphological features of the trabecular and cortical bones in comparison to the DIO model, these findings suggest that the SAD-induced weight gain was accompanied by growth via the growth hormone (GH)/Insulin-like growth factor-I (IGF-I) somatotropic axis. However, pituitary GH and plasma IGF-I levels were not different at the end point of the experiment. Igf-1 mRNA expression in the liver was significantly higher in groups that underwent RRS, which may have occurred as a compensatory mechanism for the decreased IGF-I levels during the RRS period. We also investigated whether "SAD-induced weight gain" was accompanied by a metabolic/lipid dysregulations. Plasma leptin, cholesterol, vanilmandelic acid, and free fatty acid levels were not significantly different between groups. Thus, SAD-induced weight gain is not accompanied by further increases in fat mass or metabolic dysregulations. Our results showed that the RRS and the fluoxetine treatment result in decreased plasma triglyceride levels when compared to the DIO model. Thus, the "protective" effect of fluoxetine in metabolic dysregulations may be sustained long-term. Our results suggest that individuals who are already prone to obesity may have increased risk of weight gain with antidepressant treatment. Antidepressant-induced weight gain is more likely to be associated with growth during the post-stress acclimation period, rather than with increases in fat mass and metabolic dysregulations. However, mechanisms behind the antidepressant-induced weight gain require further investigation. This thesis has contributed towards a better understanding of long-term effects of environmental factors such as stress and diet, and antidepressants in post-stress acclimation weight gain.
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Hibbert, George. „Hyperventilation in panic : cause or effect?“ Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235982.
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Hicks, Trevor. „Standardised stress management training : does it have an effect?“ Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/standardised-stress-management-training-does-it-have-an-effect(cddc9014-2eca-4a21-9ac7-d0d44f4ea86f).html.
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Stress Management Training (SMT) may be an effective treatment for patients diagnosed with anxiety and depression. An SMT package has been given to active regular military personnel diagnosed with anxiety and depression under the care of the Department of Community Mental Health (DCMH), RAF Brize Norton. The SMT was not standardised and provided psycho-education and generic anxiety management. This thesis describes attendees (n=90) of the unstandardised SMT. The unstandardised SMT was then standardised and its effectiveness was investigated by means of a Randomised Controlled Trial (RCT). The RCT compared participants (n=53) who received standardised SMT to those on the waiting list (control group) (n=45). Outcome measures used in the RCT were the General Health Questionnaire (GHQ-28), Beck Depression Inventory (BDI-II), Beck Anxiety Inventory (BAI) and Clinical Global Impression (CGI). The results of the unstandardised SMT study showed that most attendees (91%) were diagnosed with adjustment disorders prior to the study. Most attendees (57%) met the threshold, as determined by the BDI-II, for a possible depressive disorder by the time they received the unstandardised SMT. This finding was replicated in the RCT where most participants (94%) were diagnosed with adjustment disorders prior to the study but most participants (81%) exceeded the threshold, as determined by the BDI-II, for a possible depressive disorder by the time they received the standardised SMT. The results of the RCT showed that standardised SMT had a short term beneficial effect at six weeks in participants with high scores on the BDI-II but not in participants with high scores on the BAI. This effect was no longer present at 12 weeks. This thesis does not support the continued use of SMT as a tertiary stress management intervention within the military or the wider adoption of standardised SMT to treat regular, active military personnel with diagnoses of anxiety or depressive disorders. This thesis recommends that the military may wish to test the effectiveness of providing different stress management interventions as a secondary stress management intervention instead.
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France, Christopher R. (Christopher Robert). „Cardiovascular responses to psychological stress and caffeine“. Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74649.
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While considerable information exists regarding the independent effects of caffeine and psychological stress on cardiovascular activity, there is relatively little information on their combined effects. Since caffeine may enhance cardiovascular responsivity to psychological stress, research on hemodynamic responses to caffeine-stress combinations may help elucidate mechanisms of hypertension development. In a series of studies, regular consumers of caffeine were exposed to laboratory and naturalistic stressors with and without prior caffeine intake. Among the findings were (1) caffeine and stress produced additive increases in blood pressure, (2) caffeine appears to potentiate beta-adrenergic responsivity to active coping, but not passive coping, stressors, (3) caffeine enhanced emotional responses to stress, and (4) cardiovascular responses to caffeine and stress in a naturalistic setting were similar to those observed in the laboratory. These results indicate that caffeine may enhance cardiovascular and psychological responses to stress, and that these responses may contribute to risk for essential hypertension.
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Sun, Hong. „The effect of hydrodynamic stress on plant embryo development“. Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33945.
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The effect of steady shear stress on somatic embryos were investigated in a flow chamber and evaluated at different time intervals using microscopy technique. The development of meristematic cell clusters, i.e. the immature embryos, into a polarized somatic embryo, and the effect on the localization of the suspensor cells that form during development of the immature embryos, were studied as a function of shear stresses. With the distribution and growth rate of the meristematic and suspensor cells, the effect of stress on the embryo development was established. Furthermore, the effect of shear stress on the cells at molecular level, the reaction of integrin-like proteins, the production of reactive oxygen species and the pore size of the cell walls involved in the shear stress responses, were investigated with molecular techniques.
In general, shear stress inhibits meristematic cells growth. Meristematic cells grow fastest at shear rate of 86 s-1 among all the tested shear stress conditions. By combining the results of meristematic cells growth and suspensor cells formation, it suggests that there is a critical shear rate between 86 and 140 s-1, at which no suspensor cells form. The unidirectional flow with different shear stresses helps the polarized growth and the unidirectional alignment of suspensor cells. Reactive oxygen species and integrin-like protein are detected in the stressed cells as cellular responses to shear stresses. By monitoring the pore size and uptake time of cells to macromolecules with solute-exclusive experiments, it suggests that the stressed cells expedite the response to plasmolyzing components that are used to induce maturation treatment thus affect the response to maturation stimuli.
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Marckwordt, Michelle. „Effect of Early Traumatic Experience on Current Stress Levels“. Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10690957.
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Past findings regarding the effects of early trauma exposure have been contradictory, showing it to produce both resilience and vulnerability to future stressors. This may be explained by restricted samples, the use of inadequate measures of stress, and/or a failure to consider the possibility of curvilinear relationships. The present study sought to improve on past methodologies, sampling from a community population, utilizing a theory-consistent and well-validated measure of stress, and conducting quadratic regression analyses. Adult participants (N = 255) were recruited from community sites, where they completed the Lifetime Trauma Checklist, the Stress Overload Scale, and a demographic questionnaire. Analyses confirmed a curvilinear relationship between early trauma and stress overload, but not in the expected direction. Both zero- and low-exposure groups had lower levels of current stress overload than the moderate- and high-exposure group, but stress overload scores began to show a decline among the highest in the high-exposure group. The same relationship was found for one of the components of stress overload, personal vulnerability, but not the other, event load. The implications of this differential, possible explanations for the curvilinear result, and the import of these findings for both theory and practice are discussed.
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MacCombe, Diane Martha Elizabeth. „The effect of mild acid stress on environmental microorganisms“. Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491881.
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The requirement to reduce biomass production & enhance polyphosphate production during the wastewater treatment process is necessary to ensure the process is environmentally sound & cost effective. The effect of mildly acidic pH (pH6.0) on . the biomass formation & polyphosphate production by a range ofenvironmental microorganisms was investigated, using activated sludge from a trial wastewater treatment plant & a range ofenvironmental isolates. Activated sludge obtained from a treatment plant operating at pH6.0, produced lower levels of biomass alongside a higher level ofphosphate removal & higher rates ofrespiration & substrate utilisation, compared to operation ofthe same plant at higher operational pH levels. Seven pure culture isolates were also characterised in terms of their phosphate removal & biomass yields over a range ofpH values (5-.5 to 7.5). Isolates could be identified as members ofone Qfthe following: (1) demonstrate reduced biomass yields & accumulate more polyphosphate at an acidic pH, e.g. Erwinia carotovora subsp. atroseptica, (2) exhibit reduced biomass yields & polyphosphate accumulation at acidic pH e.g. Pseudomonf:ls aeruginosa PAOl, and (3) display similar or higher biomass yields at acidic pH & accumulate higher levels ofpolyphosphate at these acidic pH levels, e.g. Burkholderia cepacia AM19. Three microorganisms were studied further in continuous culture at pH6.0. E. carotovora displayed lower levels of biomass yield coupled with higher substrate utilisation rates, ATP formation rates & total intracellular P levels. B. cepacia AM19 & P. aeruginosa PAOl, in contrast displayed similar levels ofbiomass production, P removal & substrate utilisation rates. The response by E. carotovorG&activated sludge to acidic pH would suggest an increase in maintenance energy at acidic pH, caused by an increased rate ofproton pumping in order to maintain a constant intracellular pH with polyphosphate playing a protective role at acidic pH.
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Crowe, P. J. „The effect of diet and stress on substrate metabolism“. Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379881.
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Chan, Wan-Kan. „A study of the thermoelastic effect for stress analysis“. Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383253.
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Johnson, Bobbie. „Effect of stress and diapause in two Calliphoridae species“. Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4200/.
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Cultures of two Dipteran flies (Calliphora vicina (R-D) and C. vomitoria (L.)) were established to answer questions in regards to responses to thermal and desiccation stress, effects of diapause and the mechanisms which underpin diapause. The findings are divided in to two sections. Unequivocal new findings – Calliphora vomitoria were seen to depend on water being present in culture medium for increased survival. Furthermore, C. vomitoria were found to have lower desiccation resistance than C. vicina. Larvae of C. vicina and C. vomitoria showed different cold tolerance strategies, with C. vicina being freeze-avoiding and C. vomitoria ‘partially’ freeze-tolerant. Metabolomics, using \(^1\)H-NMR, revealed that diapause and non-diapause had distinct metabolic profiles. Diapause larvae were seen to reduce energy synthesis from the Krebs cycle and increase glycolysis. Calliphora vicina and C. vomitoria also exhibited different diapause phenotypes; C. vicina entered a maternally regulated facultative diapause as an L3 larvae, Calliphora vomitoria had a less distinct diapause, with maternal conditions having little effect. Speculative new findings - Despite the above differences C. vicina and C. vomitoria were able to produce a viable cross, though field fresh C. vomitoria were not used, as such it cannot be confirmed if this could occur in the wild. Increased temperatures due to climate change may affect both phenology and survival of insects; C. vicina was seen to have a delayed induction to diapause and a reduction in the proportion entering diapause. Diapause conferred increased cold tolerance; therefore those insects that overwinter not in diapause may suffer increased mortality.
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Palanki, Zoltan. „Effect of the applied stress on shape memory alloys“. Besançon, 2009. http://www.theses.fr/2009BESA2002.
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Dans cette thèse, deux modèles ont été utilisés. Celui développé à Debrecen (Hongrie) a permis de calcul les termes d'énergie non-chimique au début et à la fin de transformation martensitique. Nonobstant, non seulement ces termes sont indispensables mais la connaissance de la dépendance des termes dissipatifs élastiques à la fraction de martensite transformée est, elle aussi, importante. En conclusion, une extension de modèle s'est avérée nécessaire. Ce nouveau modèle a été utilisé afin de rationaliser les mesures effectuée sur des alliages à mémoire de forme CuAINi poly et monocristallins. Les résultats de mesures sur l'échantillon monocristallin n'ont pu être interprétés que si le concept de deux types de phase martensitique est introduit. Le modèle de Besançon (France), développé pour expliquer la transformation martensitique, introduit ce deux martensites différentes (la martensite auto-accommodante et la martensite induite par la contrainte). 0n verra que cette partition n'a aucun sens crystallographique mais est simplement utile dans une approche phénoménologique. Après qu'un lien ait été établie entre ces deux modèles et que deux phase martensitiques aient été prises en compte dans le modèle de Debrecen, la détermination des paramètre nécessaires aux simulations devient possible, et la comparaison a pu être réalisée entre les boucles hystérésis mesurées et calculéesIn this thesis two models will be concerned. The one developed earlier in Debrecen enabled to calculate the non-chemical energy terms at the start and at the end of martensitic transformation. Nevertheless not only theses points are relevant but the knowledge of the dependence of the dissipative and elastic terms on the transformed martensitic fraction in the whole transformation range is important too. Consequently an extension of the model was needed. This new model was used to evaluate the data measured on polycrystalline an single crystalline CuAINi shape memory alloys. The results of the measurements on single crystalline samples could be explained only if two types of martensitic phases were taken into account. Indeed the Besançon model developed for simulation of the martensitic transformation counts with two different martensitic phases too, namely temperature and stress induced ones. After finding the connection between these two models and took them also into account in the Debrecen-model the determination of the input parameters for the simulations became possible and comparison between the measured and calculated hysteresis loops had been made
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Lobatiuk, M., Юлія Сергіївна Козаченко, Юлия Сергеевна Козаченко und Yuliia Serhiivna Kozachenko. „Effect of stress on the occurrence of cardiovascular disease“. Thesis, Sumy State University, 2020. https://essuir.sumdu.edu.ua/handle/123456789/78025.
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Every day the modern person is exposed to stressful situations. In transport, at work, coming out of the entrance or even in our own apartment, we constantly feel stress, no matter what the profession of a person in which social and living conditions she lives, the stress accompanies her at every step. The most stressful thing is affecting the cardiovascular system, the kidneys and the digestive system.
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Crisp, William A. „Combat Posttraumatic Stress Disorder: Effect of Intelligence on Symptomatology“. Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4527/.
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The objective of this study was to examine the relations between Posttraumatic Stress Disorder symptomatology and intelligence. Thirty American combat veterans of the Vietnam War, diagnosed with chronic PTSD, were given a psychodiagnostic structured interview. Participants were assessed for Intelligence Quotient as well as the veracity of their self report. The study found that there were significant differences in how participants experienced their PTSD symptoms that were correlated with intelligence. The higher IQ participants reported more frequent and intense guilt related symptoms as well as more intense intrusive recollections. The lower IQ participants experienced more frequent startle responses, more intense problems related to falling or remaining asleep and more frequent affective symptoms related to emotional numbing. Psychologists could use these differences in how PTSD is experienced in treatment planning. It may be useful for therapy to address sleep disturbances and affective numbing in lower IQ individuals. Therapy for higher IQ individuals may be more useful if it addresses feelings of guilt and intrusive recollections.
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Didriksen, Nancy A. (Nancy Andrews). „The Effect of Examination Stress on Phagocytic Immune Functioning“. Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc500983/.
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The purpose of this study was to determine whether psychological stress, specifically examination stress, would decrease immune system functioning. Twenty-five first-year master's and doctoral students who volunteered to participate in the study were psychologically and immunologically assessed during two high- and two low-stress periods. Immunological assessments included a white blood cell differential count and nitroblue tetrazolium test (NBT) to measure neutrophil functioning. Psychological instruments administered at each assessment period included Clinical Analysis Questionnaire (CAQ), Bender Gestalt Test, State- Trait Anxiety Inventory (STAI) and a Brief Stress Questionnaire. Stepwise discriminant function analysis of data revealed five variables which contributed significantly to change under stress and yielded an average canonical correlation of .79 (p < .002) providing evidence of support for the hypothesis that increased psychological stress will alter immune functioning and heighten psychological responses.
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Kissane, Abby. „The Effect of Oxidative Stress on Myometrial miRNA Expression“. Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/scripps_theses/1072.
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Approximately 1 in 11 births in the United States are preterm (gestation). Within the United States, there are huge racial disparities for risk of preterm birth, an issue understudied and rarely addressed by research in the field. There is a wealth of biological knowledge surrounding pregnancy and labor, but causes for preterm birth are poorly understood. A genetic factor that has been shown to play a key role in many biological processes crucial to a healthy pregnancy and timely labor is microRNA (miRNA). MiRNA have an active role in the regulation of various tissues, especially developing tissues like those found in the placenta and uterus. Additionally, oxidative stress has been shown essential to placental development and the initiation of labor. Here, a study is proposed that aims to address the effect of oxidative stress on myometrial miRNA expression, specifically the miR-200 family and miR-199/214 cluster. This work also underscores the importance of addressing racial disparities with regards to preterm labor during research, while bringing up ethical considerations for conducting such research. The thesis will conclude with an outline of the many considerations vital for discussing the research and analysis of preterm birth disparities using a feminist, antiracist, queer self-reflexive analysis.
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Denison, Tracy Adam. „The effect of fluid shear stress on growth plate“. Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29603.
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Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Boyan, Barbara; Committee Co-Chair: Schwartz, Zvi; Committee Member: Bonewald, Lynda; Committee Member: Jo, Hanjoong; Committee Member: Sambanis, Athanassios. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Keeley, Maureen Patricia 1961. „THE EFFECT OF STRESS ON THE DECODER'S COMMUNICATION CHANNELS“. Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276499.
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This thesis investigated the interaction of stress and decoding accuracy through the vocalic and facial kinesic channels and with regard to gender. Stress (high and low) was created for 372 undergraduate students using the Stroop Color-Word Test. Overall, results did not show that an increase in stress led to a decrease in decoding accuracy. However, the findings did suggest that stress was impacting on the decoding process. The researcher uncovered a main effect for channel such that the facial kinesic channel was the most accurate for decoding emotions. In addition, an ordinal interaction was found during the first time period which showed that stress was differentially affecting the four groups (kinesic, high and low stress; vocalic, high and low stress). Males and females were affected in a similar manner by stress, with females being consistently more accurate decoders than males regardless of the amount of stress or channel used.
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Hollie, Alfred Henry. „Effect of Hot Spot Policing on Reducing Officer Stress“. ScholarWorks, 2019. https://scholarworks.waldenu.edu/dissertations/7390.
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Police officers endure various threats ranging from verbal abuse to physical attacks, which can escalate and lead to police officer stress. Despite the abundant research exploring the relationship between high-stress occupations and environmental health, adequate exploration of the relationship between officer stress and hot spot policing (HSP; area with an above-average level of crime) has yet to occur. The purpose of this correlational study was to use Cohen and McKay's conceptualization of the stress-buffering hypothesis to explore whether HSP mitigates the negative impact of job stress, leading to improved officer performance and ultimately improved relationships between the police and communities as well as lower crime rates. Posting of a SurveyMonkey link in law enforcement only, social-media communities (with administrator permission) facilitated data collection for the 151 respondents. Findings indicated that the overall regression model was significant; however, the simple correlation between HSP and officer stress (.118) indicated that HSP alone does not account for unique variance (there was a value of .014 or 1.4% of the variation in officer stress). The social change implications of this study include recommendations to police department administrations to continue to explore efforts to reduce officer stress, which could lead to improved officer performance and police and community relationships.
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Gasparrini, Massimiliano. „Effect of strawberry antioxidants against oxidative and inflammatory stress“. Doctoral thesis, Università Politecnica delle Marche, 2016. http://hdl.handle.net/11566/243099.
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Il primo obiettivo dello studio è stato quello di valutare e confrontare la qualità fitochimica e nutrizionale di diversi estratti di fragola, prodotti da varietà commerciali ottenute da specifici programmi di incrocio genetico. Nei vari estratti sono state misurate la capacità antiossidante totale, l'attività anti radicalica e il contenuto di polifenoli, flavonoidi, antociani, vitamina C e folati. Sulla base dei risultati ottenuti la cultivar Alba è stata scelta per condurre le analisi nella seconda parte del progetto. Il secondo obiettivo è stato quello di valutare gli effetti di estratti metanolici della cultivar Alba sull’infiammazione indotta dal LPS di E.Coli in cellule di fibroblasti di derma umano e macrofagi RAW 264.7. Dopo analisi preliminari di vitalità, apoptosi e produzione di ROS intracellulari, il ruolo protettivo degli estratti è stato stimato attraverso la valutazione dei principali biomarcatori collegati allo stress infiammatorio e ossidativo e in relazione all'attività dei principali enzimi antiossidanti. Analisi di espressione proteica sono state effettuate per identificare le principali vie molecolari coinvolte nell’azione degli estratti di fragola e del LPS E’ stato inoltre misurato il consumo di ossigeno correlato alla funzionalità mitocondriale. I risultati hanno evidenziato come gli estratti di fragola esercitino un effetto anti-infiammatorio sulle cellule trattate con LPS, riducendo la produzione di ROS e abbassando i livelli dei biomarcatori infiammatori e ossidativi. La risposta infiammatoria è stata altresì contrastata rafforzando l’attività antiossidante e regolando le vie molecolari collegate all’AMPK, registrando inoltre un miglioramento della funzionalità mitocondriale. I risultati ottenuti sottolineano e confermano il potenziale beneficio per la salute di un consumo di fragola, in particolare nei confronti delle alterazioni indotte da stress infiammatori.The first aim of this PhD project was to assess and compare the nutritional and phytochemical quality of strawberry fruit extracts of different cultivars and/or varieties, obtained through specific breeding programs: the main purpose of such approach was to evaluate the influence of genetic background on these parameters. The total antioxidant capacity, the radical scavenging activity, the content of total phenolics, flavonoids, anthocyanins, vitamin C and folates were measured in the different strawberry extracts. Among the varieties studied, the cultivar Alba was chosen for its nutritional value and was used in the second part of the Thesis. The second aim of this project was to evaluate the effects of methanolic purified extracts from Alba cultivar on inflammatory status induced by E.Coli lipopolysaccharide (LPS) on two different cell lines, Human Dermal Fibroblasts (HDF) and RAW 264.7 macrophages. The cell viability, apoptosis rate and Reactive Oxygen Species (ROS) intracellular production were assessed. The protective role of strawberry extracts was estimated by the evaluation of the principal biomarkers related to inflammatory and oxidative stress and the activity of the principal antioxidant enzymes. Moreover, protein expression was evaluated to analyze and clarify the principal molecular pathways involved in strawberry and LPS mechanisms of action. Finally, the oxygen consumption rate related to mitochondria functionality was evaluated. The results obtained demonstrated that strawberry extracts had an anti-inflammatory effect on LPS treated cells, through a reduction of ROS and inflammatory and oxidative damages. Strawberry extracts also counteracted the inflammatory response increasing the antioxidant activities, through AMPK-related pathways. An improvement of mitochondria functionality was also demonstrated. The results obtained with this work highlight and confirm the potential health benefit of strawberry against inflammatory and oxidative stress.
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Kršková, Božena. „Vyhodnocování, zvládání a snižování stresu“. Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2010. http://www.nusl.cz/ntk/nusl-222413.
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The Master’s thesis "Stress evaluation, coping and reduction" dealing with the currently very topical issue the stress acting on employee working conditions. It analyzes the types of stress, signs, symptoms and effects on health and work performance of employees. The thesis is focused on the factors causing stress, their identification and reduction of the company. The theoretical part is focused on theoretical analysis of the problems. The practical part is devoted to the measurement of stressors in the working environment for catering JHREST s.r.o. employees. The work conclusion includes a proposal of the stress factors reduction in the company.
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McDonald-Morken, Colleen Ann. „Hawk and Dove Stress Response Profiles in Humans“. Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29861.
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A recent evolutionary theory hypothesizes that there are two primary biobehavioral profiles of stress responding. Labeled "hawk" and "dove," each is characterized by divergent patterns of autonomic nervous system and neuroendocrine system activations in response to stress as well as distinct affective and behavioral tendencies. These profiles are prominent in a number of species, and it has been hypothesized that hawk-like and dovelike responses to stress may, in part, explain variability in stress-related health outcomes. This study is a preliminary investigation of hawk and dove biobehavioral profiles in humans. Participants included 73 Midwestern university students recruited from undergraduate-level psychology classes. Upon completion of a stressor task, participants answered questions regarding their psychological experiences during and immediately following the task and reported their emotions and health-related behaviors over the past several weeks. Physiological measures of cortisol and high frequency heart rate variability reactivity were used to identify relatively hawk-like and dove-like responders. Associations between patterns of physiological responding and emotional and behavioral
responses were tested. The results showed mixed support for the existence of hawk and dove biobehavioral profiles in humans.
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Quinn, Amie L., und University of Lethbridge Faculty of Arts and Science. „The impacts of agricultural chemicals and temperature on the physiological stress response in fish“. Thesis, Lethbridge, Alta. : University of Lethbirdge, Faculty of Arts and Science, 2007, 2007. http://hdl.handle.net/10133/676.
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Fish are exposed to multiple stressors in their environment. The interactive
effects of pesticide exposure and increased temperature on the physiological stress
response were investigated in a comparative field study with cold-water (whitefish,
Prosopium williamsoni) and cool-water (sucker, Catostomus) fish from the Oldman
River, Alberta, Canada, and in a laboratory study with rainbow trout, Oncorhynchus
mykiss. Physiogical stress indicators were measured, and exposure to pesticides was
estimated using acetylcholinesterase (AChE) inhibition. Species-specific differences in
AChE activities and responses of the physiological stress axis were detected in whitefish
and suckers, suggesting that whitefish are a more sensitive species to temperature and
pesticide stress. In vivo Dimethoate exposure inhibited AChE activity in various tissues
and disrupted the physiogical stress response. Commercial Dimethoate, in vitro, caused a
decrease in viability and cortisol secretion while pure grade Dimethoate did not. The
results from this study can be used in predictions of fish vulnerability to stress.ix, 137 leaves : ill. ; 29 cm.