Zeitschriftenartikel: „Stress Reduction Theory“

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Smith, Michael J., und Pascale C. Sainfort. „A balance theory of job design for stress reduction“. International Journal of Industrial Ergonomics 4, Nr. 1 (Juli 1989): 67–79. http://dx.doi.org/10.1016/0169-8141(89)90051-6.

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Lawrence, Rena M., Sally A. Lawrence, Betty Jane Lee und Nancy M. Becker. „Use of theory and cognitive activities as stress reduction strategies“. Journal of Professional Nursing 1, Nr. 5 (September 1985): 262–68. http://dx.doi.org/10.1016/s8755-7223(85)80021-1.

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Simpson, Robert, Sharon Simpson, Karen Wood, Stewart W. Mercer und Frances S. Mair. „Using normalisation process theory to understand barriers and facilitators to implementing mindfulness-based stress reduction for people with multiple sclerosis“. Chronic Illness 15, Nr. 4 (26.04.2018): 306–18. http://dx.doi.org/10.1177/1742395318769354.

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Objectives To study barriers and facilitators to implementation of mindfulness-based stress reduction for people with multiple sclerosis. Methods Qualitative interviews were used to explore barriers and facilitators to implementation of mindfulness-based stress reduction, including 33 people with multiple sclerosis, 6 multiple sclerosis clinicians and 2 course instructors. Normalisation process theory provided the underpinning conceptual framework. Data were analysed deductively using normalisation process theory constructs (coherence, cognitive participation, collective action and reflexive monitoring). Results Key barriers included mismatched stakeholder expectations, lack of knowledge about mindfulness-based stress reduction, high levels of comorbidity and disability and skepticism about embedding mindfulness-based stress reduction in routine multiple sclerosis care. Facilitators to implementation included introducing a pre-course orientation session; adaptations to mindfulness-based stress reduction to accommodate comorbidity and disability and participants suggested smaller, shorter classes, shortened practices, exclusion of mindful-walking and more time with peers. Post-mindfulness-based stress reduction booster sessions may be required, and objective and subjective reports of benefit would increase clinician confidence in mindfulness-based stress reduction. Discussion Multiple sclerosis patients and clinicians know little about mindfulness-based stress reduction. Mismatched expectations are a barrier to participation, as is rigid application of mindfulness-based stress reduction in the context of disability. Course adaptations in response to patient needs would facilitate uptake and utilisation. Rendering access to mindfulness-based stress reduction rapid and flexible could facilitate implementation. Embedded outcome assessment is desirable.

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Andrade, Cláudia Campos, und Ann Sloan Devlin. „Stress reduction in the hospital room: Applying Ulrich's theory of supportive design“. Journal of Environmental Psychology 41 (März 2015): 125–34. http://dx.doi.org/10.1016/j.jenvp.2014.12.001.

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Uskul, Ayse K. „Rethinking innovative designs to further test parasite-stress theory“. Behavioral and Brain Sciences 35, Nr. 2 (31.01.2012): 93–94. http://dx.doi.org/10.1017/s0140525x11001051.

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AbstractFincher & Thornhill's (F&T's) parasite-stress theory of sociality is supported largely by correlational evidence; its persuasiveness would increase significantly via lab and natural experiments and demonstrations of its mediating role. How the theory is linked to other approaches to group differences in psychological differences and to production and dissemination of cultural ideas and practices, need further clarification. So does the theory's view on the possible reduction of negative group interactions.

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KIDA, SOTO AKI, KEITA FUKUSHIMA und MASAYA MATSUMOTO. „THE REDUCTION OF STRESS WAVE PROPAGATION THROUGH POROUS MATERIALS“. International Journal of Modern Physics B 22, Nr. 09n11 (30.04.2008): 1215–20. http://dx.doi.org/10.1142/s0217979208046566.

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Impact stress wave propagating through porous materials is investigated in order to examine the ability of the shock absorbing effect. The specimens are modeled as the porous medium with different porous diameters made of the acrylic resin plate. When these models are impacted with different impact velocities, the impact stress waves propagating before and after the porous parts are measured using the strain gages in the experiments. As the reduction effect of the impact stress wave propagating in the porous medium, we pay attention to the maximum stresses and the duration times from the histories of the impact stress waves. One-dimensional wave theory and dynamic element method simulated this model are applied in order to explain these phenomena.

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Bernier Carney, Katherine M., Erin E. Young, Jessica W. Guite und Angela R. Starkweather. „A Systematic Review of Biological Mechanisms and Chronic Pain Outcomes During Stress Reduction Interventions“. Biological Research For Nursing 22, Nr. 2 (16.03.2020): 205–16. http://dx.doi.org/10.1177/1099800420907964.

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Background: Nonpharmacologic stress reduction interventions provide an opportunity to modify chronic pain trajectories; however, the biological mechanisms underlying these interventions are poorly understood. Objectives: To examine clinical literature published in 2012–2018 with the goals of (1) identifying which biological mechanisms or biomarkers are currently being measured in nonpharmacologic stress reduction intervention studies for individuals with chronic pain and (2) evaluating the evidence to determine whether these stress reduction interventions lead to changes in (a) pain outcomes and/or (b) measured biomarkers. Data sources: Scientific articles in the electronic databases PubMed/Medline, Cumulative Index of Nursing and Allied Health Literature, PsychINFO, and SCOPUS following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Study selection: Randomized controlled trials and quasi-experimental studies that recruited subjects with a chronic pain condition, examined a relationship between a nonpharmacologic stress reduction intervention and pain-related outcome(s), and included measurement of a biomarker. Results: The 13 articles that met inclusion criteria spanned four nonpharmacologic stress reduction categories: mindfulness-based stress reduction, physical exercise, manual therapies, and biofeedback. Methods for studying biomarkers included measuring biological samples, neurological function, and autonomic control. Although all studies investigated both biological measures and pain outcomes, only three demonstrated an association between the biomarker(s) and pain-related outcomes. Conclusions: The results of this review highlight the complex nature of stress–pain relationships and the lack of rigorous clinical research identifying specific stress-related biological factors that modulate pain outcomes. Stress reduction interventions remain a favorable method for symptom management in patients living with chronic pain, but consistency in study measures and design is needed for robust evaluation.

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SAITO, Yumi, und Harue TADA. „Effects of color images on stress reduction: Using images as mood stimulants“. Japan Journal of Nursing Science 4, Nr. 1 (Juni 2007): 13–20. http://dx.doi.org/10.1111/j.1742-7924.2007.00068.x.

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Bagley, E. B., und D. D. Christianson. „Stress Relaxation of Chemically Leavened Dough—Data Reduction Using the BKZ Elastic Fluid Theory“. Journal of Rheology 31, Nr. 5 (Juli 1987): 405–13. http://dx.doi.org/10.1122/1.549929.

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Escolà-Gascón, Álex, und James Houran. „Paradoxical effects of exposure to nature in “haunted” places: Implications for stress reduction theory“. Landscape and Urban Planning 214 (Oktober 2021): 104183. http://dx.doi.org/10.1016/j.landurbplan.2021.104183.

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Louthan, Allison M., Daniel F. Doak, Jacob R. Goheen, Todd M. Palmer und Robert M. Pringle. „Mechanisms of plant–plant interactions: concealment from herbivores is more important than abiotic-stress mediation in an African savannah“. Proceedings of the Royal Society B: Biological Sciences 281, Nr. 1780 (07.04.2014): 20132647. http://dx.doi.org/10.1098/rspb.2013.2647.

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Recent work on facilitative plant–plant interactions has emphasized the importance of neighbours’ amelioration of abiotic stress, but the facilitative effects of neighbours in reducing plant apparency to herbivores have received less attention. Whereas theory on stress reduction predicts that competition should be more important in less stressful conditions, with facilitation becoming more important in harsh environments, apparency theory suggests that facilitation should be greater in the presence of herbivores, where it is disadvantageous to be conspicuous regardless of abiotic stress level. We tested the relative strength of neighbours’ stress reduction versus apparency reduction on survival, growth, reproduction and lifetime fitness of Hibiscus meyeri , a common forb in central Kenya, using neighbour removals conducted inside and outside large-herbivore exclosures replicated in arid and mesic sites. In the absence of herbivores, neighbours competed with H. meyeri in mesic areas and facilitated H. meyeri in arid areas, as predicted by stress-reduction mechanisms. By contrast, neighbours facilitated H. meyeri in the presence of herbivory, regardless of aridity level, consistent with plant apparency. Our results show that the facilitative effects arising from plant apparency are stronger than the effects arising from abiotic stress reduction in this system, suggesting that plant-apparency effects may be particularly important in systems with extant large-herbivore communities.

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LEE, CHANGHOON, JOHN KIM und HAECHEON CHOI. „Suboptimal control of turbulent channel flow for drag reduction“. Journal of Fluid Mechanics 358 (10.03.1998): 245–58. http://dx.doi.org/10.1017/s002211209700815x.

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Two simple feedback control laws for drag reduction are derived by applying a suboptimal control theory to a turbulent channel flow. These new feedback control laws require pressure or shear-stress information only at the wall, and when applied to a turbulent channel flow at Reτ=110, they result in 16–22% reduction in the skin-friction drag. More practical control laws requiring only the local distribution of the wall pressure or one component of the wall shear stress are also derived and are shown to work equally well.

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Lengacher, Cecile A., Kevin E. Kip, Janice Post-White, Shirley Fitzgerald, Cathy Newton, Michelle Barta, Paul B. Jacobsen et al. „Lymphocyte Recovery After Breast Cancer Treatment and Mindfulness-Based Stress Reduction (MBSR) Therapy“. Biological Research For Nursing 15, Nr. 1 (14.11.2011): 37–47. http://dx.doi.org/10.1177/1099800411419245.

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Objectives:This randomized controlled trial was conducted to examine immune recovery following breast cancer (BC) therapy and evaluate the effect of mindfulness-based stress reduction therapy (MBSR) on immune recovery with emphasis on lymphocyte subsets, T cell activation, and production of T-helper 1 (Th1; interferon [IFN]-γ) and T-helper 2 (Th2; interleukin-4 [IL-4]) cytokines.Method:Participants who completed the study consisted of 82 patients diagnosed with Stage 0–III BC, who received lumpectomy and adjuvant radiation ± chemotherapy. Patients were randomized into an MBSR(BC) intervention program or a control (usual care) group. Immune cell measures were assessed at baseline and within 2 weeks after the 6-week intervention. The numbers and percentages of lymphocyte subsets, activated T cells, and Th1 and Th2 cells in peripheral blood samples were determined by immunostaining and flow cytometry.Results:Immune subset recovery after cancer treatment showed positive associations with time since treatment completion. The B and natural killer (NK) cells were more susceptible than T cells in being suppressed by cancer treatment. Women who received MBSR(BC) had T cells more readily activated by the mitogen phytohemagglutinin (PHA) and an increase in the Th1/Th2 ratio. Activation was also higher for the MBSR(BC) group if <12 weeks from the end of treatment and women in MBSR(BC) <12 weeks had higher T cell count for CD4+.Conclusion:MBSR(BC) promotes a more rapid recovery of functional T cells capable of being activated by a mitogen with the Th1 phenotype, whereas substantial recovery of B and NK cells after completion of cancer treatment appears to occur independent of stress-reducing interventions.

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Smith, Sarah A. „Mindfulness-Based Stress Reduction: An Intervention to Enhance the Effectiveness of Nurses' Coping With Work-Related Stress“. International Journal of Nursing Knowledge 25, Nr. 2 (26.02.2014): 119–30. http://dx.doi.org/10.1111/2047-3095.12025.

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Zhou, Rong, Jun Hai Zhao und Xue Ying Wei. „Research on Bearing Capacity of Concrete Filled Double Skin (CHS Inner and SHS Outer) under Eccentric Compression“. Applied Mechanics and Materials 723 (Januar 2015): 422–26. http://dx.doi.org/10.4028/www.scientific.net/amm.723.422.

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The ultimate load calculation formula for the solid multi barrel tube-confined concrete columns (CHS inner and SHS outer) was derived based on the Unified Strength Theory (UST) in this paper. The influence of intermediate principal stress and the double restriction effect and the decrease of longitudinal stress were considered in the formula. Based on the axial compression load and consider the eccentricity ratio and slenderness ratio, by introducing the reduction factor of concrete strength and the equivalent restriction reduction factor, based on unified strength theory solutions of thick tube, combined with concrete filled skin tube unified theory, deduce the calculation formula of eccentric compression bearing capacity of concrete filled steel tubular columns and analysis the influence complication.

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Roberts, Lisa R., G. Griffin Boostrom, Salem O. Dehom und Cameron L. Neece. „Self-Reported Parenting Stress and Cortisol Awakening Response Following Mindfulness-Based Stress Reduction Intervention for Parents of Children With Developmental Delays: A Pilot Study“. Biological Research For Nursing 22, Nr. 2 (22.11.2019): 217–25. http://dx.doi.org/10.1177/1099800419890125.

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Background: Many parents of children with developmental delays (DDs) experience high levels of parental stress, and young children with DDs are likely to exhibit clinical levels of behavioral problems. The reciprocal relationship between the two issues makes these families vulnerable to stress-related health risks. To address this, the current study aims to investigate the effectiveness of mindfulness-based stress reduction (MBSR) at reducing parent stress, as measured by both psychological self-report and a physiological biomarker. Method: A pretest–posttest design with a 6-month follow-up assessment was used to establish effectiveness with analyses of within-subject effects. Parents ( N = 47) of children (2.5–5 years of age) with DDs participated in a standard 8-week MBSR intervention. Measures included the Parenting Daily Hassles, a self-report measure of perceived frequency and intensity of parenting stress, and salivary samples for measurement of the cortisol awakening response (CAR), a biological marker of stress response. Results: Both self-reported parenting stress and CAR decreased following MBSR for parents of children with DDs. The greatest difference in means over time was between baseline and follow-up, where changes in effect size were even stronger for biological markers than for self-report measures. Conclusion: The MBSR intervention reduced both perceived and physiologic stress. Health-care professionals caring for these families might consider encouraging parents to participate in MBSR as both treatment and prevention of parenting stress.

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Ai, Xiaolan. „Effect of Three-Dimensional Random Surface Roughness on Fatigue Life of a Lubricated Contact“. Journal of Tribology 120, Nr. 2 (01.04.1998): 159–64. http://dx.doi.org/10.1115/1.2834403.

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A means of evaluating the surface roughness effect on contact fatigue life has been proposed. To account for stress variations caused by random surface roughness, an effective stress concept based on damage accumulation theory was employed. A point EHL analysis along with a comprehensive interior stress analysis has been performed to obtain the effective stress field under lubricated conditions. Numerical simulations were performed for surfaces produced by different finishing processes. Results show that surface roughness can cause significant stress variations in the near-surface. As a result, the effective stress at the near-surface is increased. The increased effective stress is responsible for the life reduction of the contact. Life reduction factors for contact surfaces with different finishing processes were compared.

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Ludick, Marné, und Charles R. Figley. „Toward a mechanism for secondary trauma induction and reduction: Reimagining a theory of secondary traumatic stress.“ Traumatology 23, Nr. 1 (März 2017): 112–23. http://dx.doi.org/10.1037/trm0000096.

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Lu, Yong, Yingguang Li, Nanya Li und Xiaochun Wu. „Reduction of composite deformation based on tool-part thermal expansion matching and stress-free temperature theory“. International Journal of Advanced Manufacturing Technology 88, Nr. 5-8 (21.05.2016): 1703–10. http://dx.doi.org/10.1007/s00170-016-8862-3.

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Kan, Nahomi, Masashi Kuniyasu und Kiyoshi Shiraishi. „Quantum fluctuation of stress tensor in a higher-derivative scalar field theory around a cosmic string“. International Journal of Modern Physics A 36, Nr. 20 (09.07.2021): 2150150. http://dx.doi.org/10.1142/s0217751x21501505.

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In this paper, we calculate the vacuum fluctuation of the stress tensor of a higher-derivative theory around a thin cosmic string. To this end, we adopt the method to obtain the stress tensor from the effective action developed by Gibbons et al. By their method, the quantum stress tensor of higher-derivative scalar theories without self-interaction is expressed as a simple sum of quantum stress tensors of free massive scalar fields. Unlike the vacuum expectation value of the scalar field squared obtained in the similar model, there appears no reduction of the values near the conical singularity.

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King, Shirley L., und Kathy M. Hegadoren. „Stress Hormones: How Do They Measure Up?“ Biological Research For Nursing 4, Nr. 2 (Oktober 2002): 92–103. http://dx.doi.org/10.1177/1099800402238334.

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Stress as a stimulus is integral to dynamic homeostatic functioning. However, evidence of its potentially deleterious effects on health is mounting. The impetus to understand the mechanisms that underlie stress-related negative health outcomes and prevent the development of stress-related disorders has never been greater. Symptom severity and subjective levels of stress, although frequently assessed in studies of stress in nursing research, may not provide adequate data to fully understand the pervasive effects of chronic or overwhelming stress associated with stress disorders. The measurement of stress hormones such as cortisol can help identify bodily changes that are stressor specific, people at risk for development of stress-related disorders, and the efficacy of interventions aimed at stress reduction. Cortisol, as the peripheral output of one of the major stress response systems, possesses several properties that make its measurement highly useful for investigations of stress. This article discusses some of the biological mechanisms involved in the stress response, why cortisol is commonly measured, and issues and approaches in cortisol measurement.

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Shi, Chong, Yu Long Zhang, Qiang Zahng, Hai Li Wang und Sheng Nian Wang. „Safety Factor Calculation Method of Anchored Slope Based on Pseudo Cohesion Theory“. Applied Mechanics and Materials 170-173 (Mai 2012): 453–56. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.453.

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The stability of slope is closely related to stress-state. Assumptions about stress-state in the rigid body limit equilibrium method are not satisfied with the demands of deformation compatibility principle. So the stability analysis method compatible with slope stress and anchorage system should be established for anchored slope. The pseudo cohesion concept theory is used to analyze the improvement of stress-state due to anchoring measures, and the stability safety factor of anchored slope by sliding surfaces searching method is obtained, in which grid control is used and embedded in FLAC3D. The result shows that the safety factor with the pseudo cohesion theory is 1.43 while the strength reduction method is 1.41. The similar results for them show the validity of proposed method. What's more, the suggested method has an advantage of short time consuming.

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Zhang, Jing, Hong Guang Jia, Ling Ding und Wen Hui Dong. „Buffer and Vibration Optimization of Missile Data Recorder Structure“. Advanced Materials Research 328-330 (September 2011): 2304–7. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.2304.

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On the analysis of the original data recorder, made several key problems clear when buffer and damping, distinguished between a cushion theory and application field of stress wave theory, the traditional rigid spring-buffer model whose object is to reduce the impact of acceleration that can not accurately describe the elastic force of the part of the actual situation; the stress wave theory is the elastic theory can explain the filter buffer question from the micro-small space, from this designed a composite structure for vibration reduction, which made the dynamic stress of protected component down about one order of magnitude. Optimization with Isight and Ls-dyna, the protected component's dynamic stress down about 69.3% and the data recorder's quality 300g lower, finally passed the Marshall Hammer test successfully.

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Seng, Ong Lin. „Effectiveness of Wear Plate at the Saddle Support“. Journal of Pressure Vessel Technology 114, Nr. 1 (01.02.1992): 12–18. http://dx.doi.org/10.1115/1.2929004.

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A theory is presented to analyze the effectiveness of incorporating a wear plate at the saddle support of a cylindrical pressure vessel. The wear plate can be either welded to the vessel or of loose fitting. The theory is based on a contact stress formulation together with the use of a cylindrical shell bending theory for simply supported cylinder. The effectiveness of the wear plate in reducing the peak circumferential saddle-horn stress is quantified by definition of a stress reduction factor. Parametric data are carried out for the saddle angle of 120 deg. From the study, the optimum thickness of the wear plate for three different angular extensions, are obtained.

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Sayers, Colin M. „Stress‐dependent seismic anisotropy of shales“. GEOPHYSICS 64, Nr. 1 (Januar 1999): 93–98. http://dx.doi.org/10.1190/1.1444535.

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A simple theory for the stress‐dependent seismic anisotropy of shales can be obtained in terms of a second‐rank tensor and a fourth‐rank tensor that depend on the orientation distribution of contacts between clay platelets. The theory allows the normal and shear stiffness of the contact regions between clay platelets to be obtained as a function of stress from measurements of seismic P- and S-wave velocities for shales. The ratio of the normal‐to‐shear compliance, [Formula: see text], of the contact regions between clay particles is found to be sensitive to the saturation state of the shale. Inversion of velocity measurements for fully saturated shales shows a low value of [Formula: see text] when compared with measurements on air‐dry shales, consistent with the expected reduction in normal compliance in a fluid‐saturated, low‐permeability rock. For all shales considered, [Formula: see text] is found to be less than unity. The contacts between clay particles are therefore more compliant in shear than in compression.

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Mitchel, Cary A. „990 RECENT ADVANCES IN PLANT RESPONSE TO MECHANICAL STRESS: THEORY AND APPLICATION“. HortScience 29, Nr. 5 (Mai 1994): 571a—571. http://dx.doi.org/10.21273/hortsci.29.5.571a.

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Brief, periodic seismic (shaking) or thigmic (contact rubbing) stress treatments applied to plants growing in a wind-protected environment typically reduce but strengthen vegetative growth and often inhibit reproductive development. Cell division and cell enlargement both are affected. Mechanically dwarfed plants accumulate less leaf area than do undisturbed controls and undergo temporary stomatal aperture reduction following an episode of stress, leading to reduced photosynthetic productivity. Vibration or mild shaking may lead to a slight stimulation of plant growth. Most classes of phytohormones have been implicated to mediate different growth responses to mechanical stress. Physical perturbation turns on the transcription of several genes coding for calmodulin-like proteins. Calcium chelators and calmodulin inhibitors partially negate effects of thigmic stress. Growth rate responses of naive seedlings are immediate and dramatic, suggesting turgor collapse, whereas recoveries are slow and sometimes partial, suggesting reduced wall extensibility in the cell enlargement zone. Mechanical stress may be used for height control of intensively cultivated bench crops or to physically toughen bedding plants prior to outdoor transplant. Physiological hardening remains a question. Mechanical height control avoids use of chemicals but increases risk of wounding and pathogen infection.

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Lengacher, Cecile A., Richard R. Reich, Kevin E. Kip, Michelle Barta, Sophia Ramesar, Carly L. Paterson, Manolete S. Moscoso et al. „Influence of Mindfulness-Based Stress Reduction (MBSR) on Telomerase Activity in Women With Breast Cancer (BC)“. Biological Research For Nursing 16, Nr. 4 (30.01.2014): 438–47. http://dx.doi.org/10.1177/1099800413519495.

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Mindfulness-based stress reduction (MBSR) reduces symptoms of depression, anxiety, and fear of recurrence among breast cancer (BC) survivors. However, the effects of MBSR (BC) on telomere length (TL) and telomerase activity (TA), known markers of cellular aging, psychological stress, and disease risk, are not known. This randomized, wait-listed, controlled study, nested within a larger trial, investigated the effects of MBSR (BC) on TL and TA. BC patients (142) with Stages 0–III cancer who had completed adjuvant treatment with radiation and/or chemotherapy at least 2 weeks prior to enrollment and within 2 years of completion of treatment with lumpectomy and/or mastectomy were randomly assigned to either a 6-week MBSR for BC program or a usual care. Assessments of TA and TL were obtained along with psychological measurements at baseline, 6 weeks, and 12 weeks after completing the MBSR(BC) program. The mean age of 142 participants was 55.3 years; 72% were non-Hispanic White; 78% had Stage I or II cancer; and 36% received both chemotherapy and radiation. In analyses adjusted for baseline TA and psychological status, TA increased steadily over 12 weeks in the MBSR(BC) group (approximately 17%) compared to essentially no increase in the control group (approximately 3%, p < .01). In contrast, no between-group difference was observed for TL ( p = .92). These results provide preliminary evidence that MBSR(BC) increases TA in peripheral blood mononuclear cells from BC patients and have implications for understanding how MBSR(BC) may extend cell longevity at the cellular level.

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Huddleston, R. L. „Assessment of an Improved Multiaxial Strength Theory Based on Creep-Rupture Data for Type 316 Stainless Steel“. Journal of Pressure Vessel Technology 115, Nr. 2 (01.05.1993): 177–84. http://dx.doi.org/10.1115/1.2929513.

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A new multiaxial strength theory incorporating three independent stress parameters was developed and reported by the author in 1984. It was formally incorporated into ASME Code Case N47-29 in 1990. In the earlier paper, the new model was shown to provide significantly more accurate stress-rupture life predictions than the classical theories of von Mises, Tresca, and Rankine, for type 304 stainless steel tested at 593°C under different biaxial stress states. Further assessments for other alloys are showing similar results. The current paper provides additional results for type 316 stainless steel specimens tested at 600°C under tension-tension and tension-compression stress states and shows 2–3 orders of magnitude reduction in the scatter in predicted versus observed lives. A key feature of the new theory, which incorporates the maximum deviatoric stress, the first invariant of the stress tensor, and the second invariant of the deviatoric stress tensor, is its ability to distinguish between life under tensile versus compressive stress states.

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Bathe, M., und R. D. Kamm. „A Fluid-Structure Interaction Finite Element Analysis of Pulsatile Blood Flow Through a Compliant Stenotic Artery“. Journal of Biomechanical Engineering 121, Nr. 4 (01.08.1999): 361–69. http://dx.doi.org/10.1115/1.2798332.

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A new model is used to analyze the fully coupled problem of pulsatile blood flow through a compliant, axisymmetric stenotic artery using the finite element method. The model uses large displacement and large strain theory for the solid, and the full Navier-Stokes equations for the fluid. The effect of increasing area reduction on fluid dynamic and structural stresses is presented. Results show that pressure drop, peak wall shear stress, and maximum principal stress in the lesion all increase dramatically as the area reduction in the stenosis is increased from 51 to 89 percent. Further reductions in stenosis cross-sectional area, however, produce relatively little additional change in these parameters due to a concomitant reduction in flow rate caused by the losses in the constriction. Inner wall hoop stretch amplitude just distal to the stenosis also increases with increasing stenosis severity, as downstream pressures are reduced to a physiological minimum. The contraction of the artery distal to the stenosis generates a significant compressive stress on the downstream shoulder of the lesion. Dynamic narrowing of the stenosis is also seen, further augmenting area constriction at times of peak flow. Pressure drop results are found to compare well to an experimentally based theoretical curve, despite the assumption of laminar flow.

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Nakacho, K., und Y. Ueda. „A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part II: The Characteristics of Reduction of Welding Residual Stresses in Very Thick Joints During SR Treatment“. Journal of Pressure Vessel Technology 121, Nr. 1 (01.02.1999): 11–16. http://dx.doi.org/10.1115/1.2883659.

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Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is considerably similar to that observed in the SR treatment of a joint. In this report, the stresses relaxed by SR treatment in a very thick welded joint are analyzed accurately by the finite element method based on thermal elastic-plastic-creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state are studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

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Hans, Marcus, Lena Patterer, Denis Music, Damian M. Holzapfel, Simon Evertz, Volker Schnabel, Bastian Stelzer et al. „Stress-Dependent Elasticity of TiAlN Coatings“. Coatings 9, Nr. 1 (02.01.2019): 24. http://dx.doi.org/10.3390/coatings9010024.

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We investigate the effect of continuous vs. periodically interrupted plasma exposure during cathodic arc evaporation on the elastic modulus as well as the residual stress state of metastable cubic TiAlN coatings. Nanoindentation reveals that the elastic modulus of TiAlN grown at floating potential with continuous plasma exposure is 7%–11% larger than for coatings grown with periodically interrupted plasma exposure due to substrate rotation. In combination with X-ray stress analysis, it is evident that the elastic modulus is governed by the residual stress state. The experimental dependence of the elastic modulus on the stress state is in excellent agreement with ab initio predictions. The macroparticle surface coverage exhibits a strong angular dependence as both density and size of incorporated macroparticles are significantly lower during continuous plasma exposure. Scanning transmission electron microscopy in combination with energy dispersive X-ray spectroscopy reveals the formation of underdense boundary regions between the matrix and TiN-rich macroparticles. The estimated porosity is on the order of 1% and a porosity-induced elastic modulus reduction of 5%–9% may be expected based on effective medium theory. It appears reasonable to assume that these underdense boundary regions enable stress relaxation causing the experimentally determined reduction in elastic modulus as the population of macroparticles is increased.

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Jordan, A. S., E. M. Monberg und J. E. Clemans. „Thermal stress theory of dislocation reduction in the vertical gradient freeze (VGF) growth of GaAs and InP“. Journal of Crystal Growth 128, Nr. 1-4 (März 1993): 444–50. http://dx.doi.org/10.1016/0022-0248(93)90364-3.

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Li, Xiao Wei, Jun Hai Zhao und Qi Yao Wang. „Maximum Reduction in Thickness in a Single Sheet Forming Pass Based on Unified Strength Theory“. Applied Mechanics and Materials 159 (März 2012): 151–55. http://dx.doi.org/10.4028/www.scientific.net/amm.159.151.

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Based on unified strength theory, the equation for estimating the maximum reduction in thickness in a single sheet forming pass is obtained. Included the contribution of both intermediate principal shear stress and varying tension-compression-ratio to material mechanical property, the equation developed by this paper can reasonably apply to a wide range of material. It can be proved that the equation for estimating the maximum reduction based on unified strength theory becomes that based on unified yield criterion, when material has equal strength in tension and compression, i.e., the tension-compression-ratio of material is equal to units; and, that the values of the maximum reduction obtained previously based on Mises, or Tresca criterion, are all just special cases of those based on unified yield criterion. In addition, the maximum reduction in thickness for sheet drawing and extrusion is equal to one another.

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Liu, Zhi Jie, Jun Hai Zhao, Xu Guang Yu, Gai Qin Su und Xin Zhao. „The Square Steel Tube Columns Filled with Steel-Reinforced Concrete Bias Supporting Capacity Unified Solution“. Applied Mechanics and Materials 193-194 (August 2012): 1418–23. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.1418.

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The eccentric ultimate load calculation formula of square steel tube columns filled with steel-reinforced concrete was derived based on the Unified Strength Theory in this paper. The influence of intermediate principal stress and the restriction effect and the decrease of longitudinal stress were considered in the formula. Based on the axial compression load and the effect of consider the eccentricity ratio and slenderness ratio on the hearing capacity was considered, by introducing the reduction factor of concrete strength and the equivalent restriction reduction factor, the confinement of square steel tube towards concrete was equivalent to the confinement of circular steel tube towards it, based on unified strength theory solutions of thick tube, the calculation formula of eccentric compression bearing capacity of square steel tube columns filled with steel-reinforced concrete was deduced and analysed the influence complication. The results indicate unified strength theory has the good applicability and the solution has an important practical value for engineering application.

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Xu, Jin, und Chun Xia Wang. „Study on Application of Grey System Theory in Fatigue Span Design of Machine Tool Axles“. Advanced Materials Research 201-203 (Februar 2011): 1156–60. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.1156.

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The interdependent relationship of fatigue stress and span was regarded as a grey system using grey system theory and method. The stress level of fatigue test was uniformly divided into many grades and the whiting value of safe span was found out. A smooth discrete function was formed based on one accumulation of safe span value series. Therefore, the model of grey system was set up and the differential equation of grey system was solved. The accuracy of model was improved by revising the residual model. The safe span value at every stress level could be calculated using the reduction model of the grey system. It provided a new way for the safe span calculation of mechanical parts, which would be of great application value.

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NAZARENKO, S., N. K. R. KEVLAHAN und B. DUBRULLE. „WKB theory for rapid distortion of inhomogeneous turbulence“. Journal of Fluid Mechanics 390 (10.07.1999): 325–48. http://dx.doi.org/10.1017/s0022112099005340.

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A WKB method is used to extend RDT (rapid distortion theory) to initially inhomogeneous turbulence and unsteady mean flows. The WKB equations describe turbulence wavepackets which are transported by the mean velocity and have wavenumbers which evolve due to the mean strain. The turbulence also modifies the mean flow and generates large-scale vorticity via the averaged Reynolds stress tensor. The theory is applied to Taylor's four-roller flow in order to explain the experimentally observed reduction in the mean strain. The strain reduction occurs due to the formation of a large-scale vortex quadrupole structure from the turbulent spot confined by the four rollers. Both turbulence inhomogeneity and three-dimensionality are shown to be important for this effect. If the initially isotropic turbulence is either homogeneous in space or two-dimensional, it has no effect on the large-scale strain. Furthermore, the turbulent kinetic energy is conserved in the two-dimensional case, which has important consequences for the theory of two-dimensional turbulence. The analytical and numerical results presented here are in good qualitative agreement with experiment.

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Su, Dengfeng, Yong Kang, Dongyang Li, Xiaochuan Wang und Fuwen Yan. „Analysis and Numerical Simulation on the Reduction Effect of Stress Waves Caused by Water Jet Slotting Near Blasting Source“. Shock and Vibration 2016 (2016): 1–18. http://dx.doi.org/10.1155/2016/5640947.

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As one of the most serious “side effects” of blast excavation, blast-induced vibration must be controlled for existing buildings and human beings. This paper proposes a method for blast-induced vibration reduction with water jet assistance according to the cutting characters of low-noised, environment-friendly water jet. The mechanism of vibration-isolation with water jet assistance was analyzed, and the stress wave energy attenuation models were established based on blasting theory and stress wave theory. Influence law on shock wave attenuation by vibration-isolation slot was studied by numerical simulation. Simulation results agree with the theoretical analysis roughly. The results of this study put forward a method for blast-induced vibration near blasting source and provide a certain theoretical basis.

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Zhai, Zhanyu, Bingyan Jiang und Dietmar Drummer. „Nonlinear Material Model for Quasi-Unidirectional Woven Composite Accounting for Viscoelastic, Viscous Deformation, and Stiffness Reduction“. Polymers 10, Nr. 8 (11.08.2018): 903. http://dx.doi.org/10.3390/polym10080903.

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To clarify the individual contribution of viscoelastic and viscous deformation to the global nonlinear response of composites, multilevel cyclic loading-unloading recovery tensile tests were carried out. The experimental results show that there is a linear relationship between the viscous strain and viscoelastic strain of composites, regardless of the off-axis angle or loading stress level. On the basis of experimental results, a coupled damage-plasticity constitutive model was proposed. In this model, the plasticity theory was adopted to assess the evolution of viscous strains. The viscoelastic strain was represented as a linear function of viscous strains. Moreover, the Weibull function of the effective stress was introduced to evaluate the damage variables in terms of stiffness reduction. The tensile stress-strain curves, predicted by the proposed model, showed a good agreement with experimental results.

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Lengacher, Cecile A., Richard R. Reich, Carly L. Paterson, Melissa Shelton, Steve Shivers, Sophia Ramesar, Michelle L. Pleasant et al. „A Large Randomized Trial: Effects of Mindfulness-Based Stress Reduction (MBSR) for Breast Cancer (BC) Survivors on Salivary Cortisol and IL-6“. Biological Research For Nursing 21, Nr. 1 (05.08.2018): 39–49. http://dx.doi.org/10.1177/1099800418789777.

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Breast cancer survivors (BCS) often experience psychological and physiological symptoms after cancer treatment. Mindfulness-based stress reduction (MBSR), a complementary and alternative therapy, has reduced subjective measures of stress, anxiety, and fatigue among BCS. Little is known, however, about how MBSR affects objective markers of stress, specifically the stress hormone cortisol and the pro-inflammatory cytokine interleukin-6 (IL-6). In the present study, BCS ( N = 322) were randomly assigned to a 6-week MBSR program for BC or usual-care control. Measurements of cortisol, IL-6, symptoms, and quality of life were obtained at orientation and 6 weeks. Cortisol and IL-6 were also measured prior to and after the MBSR(BC) class Weeks 1 and 6. The mean age of participants was 56.6 years and 69.4% were White non-Hispanic. Most had Stage I (33.8%) or II (35.7%) BC, and 35.7% had received chemotherapy and radiation. Cortisol levels were reduced immediately following MBSR(BC) class compared to before the class Weeks 1 and 6 (Wilcoxon-signed rank test; p < .01, d = .52–.56). IL-6 was significantly reduced from pre- to postclass at Week 6 (Wilcoxon-signed rank test; p < .01, d = .21). No differences were observed between the MBSR(BC) and control groups from baseline to Week 6 using linear mixed models. Significant relationships with small effect sizes were observed between IL-6 and both symptoms and quality of life in both groups. Results support the use of MBSR(BC) to reduce salivary cortisol and IL-6 levels in the short term in BCS.

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Noel, Nora E., und Dale J. Cohen. „Changes in Substance Use during Times of Stress: College Students the Week before Exams“. Journal of Drug Education 27, Nr. 4 (Dezember 1997): 363–72. http://dx.doi.org/10.2190/1yg0-lxfk-mu18-u0kt.

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A situational factor that is commonly thought to influence substance use is stress. The tension reduction theory posits that alcohol relieves stress-reactions and that most people drink alcohol in stressful situations in order to relieve stress-reactions. We conducted a naturalistic study in which we surveyed seventy-three college students' alcohol and drug use, behaviors, and emotions during a typical week and the week before final exams. As expected our subjects experienced an increase in aversive emotions during the week before exams. The simple tension reduction hypothesis predicts that these subjects' alcohol use should have increased during this time. Our data showed the opposite: subjects' alcohol use decreased during the week before exams. We hypothesized that this was due to the availability of effective alternatives for reducing anxiety. Implications for prevention were discussed.

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Weigensberg, Marc J., Cheryl Vigen, Paola Sequeira, Donna Spruijt-Metz, Magaly Juarez, Daniella Florindez, Joseph Provisor, Anne Peters und Elizabeth A. Pyatak. „Diabetes Empowerment Council: Integrative Pilot Intervention for Transitioning Young Adults With Type 1 Diabetes“. Global Advances in Health and Medicine 7 (Januar 2018): 216495611876180. http://dx.doi.org/10.1177/2164956118761808.

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Background The transition of young adults with type 1 diabetes (T1D) from pediatric to adult care is challenging and frequently accompanied by worsening of diabetes-related health. To date, there are no reports which prospectively assess the effects of theory-based psycho-behavioral interventions during the transition period neither on glycemic control nor on psychosocial factors that contribute to poor glycemic control. Therefore, the overall aim of this study was to develop and pilot test an integrative group intervention based on the underlying principles of self-determination theory (SDT), in young adults with T1D. Methods Fifty-one young adults with T1D participated in an education and case management-based transition program, of which 9 took part in the Diabetes Empowerment Council (DEC), a 12-week holistic, multimodality facilitated group intervention consisting of “council” process based on indigenous community practices, stress-reduction guided imagery, narrative medicine modalities, simple ritual, and other integrative modalities. Feasibility, acceptability, potential mechanism of effects, and bio-behavioral outcomes were determined using mixed qualitative and quantitative methods. Results The intervention was highly acceptable to participants, though presented significant feasibility challenges. Participants in DEC showed significant reductions in perceived stress and depression, and increases in general well-being relative to other control participants. Reduction in perceived stress, independent of intervention group, was associated with reductions in hemoglobin A1C. A theoretical model explaining the effects of the intervention included the promotion of relatedness and autonomy support, 2 important aspects of SDT. Conclusions The DEC is a promising group intervention for young adults with T1D going through transition to adult care. Future investigations will be necessary to resolve feasibility issues, optimize the multimodality intervention, determine full intervention effects, and fully test the role of the underlying theoretical model of action. ClinicalTrials.gov Registration Number NCT02807155; Registration date: June 15, 2016 (retrospectively registered)

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Li, Yang, Yun Xin Wu, Hai Gong und Feng Xiao. „FEM and Contour Method Study of Quenching Residual Stress of 7050 Aluminum Alloy Cross-Shaped Component“. Materials Science Forum 887 (März 2017): 89–95. http://dx.doi.org/10.4028/www.scientific.net/msf.887.89.

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In order to study the quenching residual stress of typical aluminum alloy component used in aerospace, the finite element (FE) model of quenching process of 7050 aluminum alloy cross-shaped component was established based on heat transfer theory and elastic-plastic mechanics theory, the distribution regularities of quenching residual stress field of cross-shaped component was analyzed. The results indicate that the residual stress distribution of web of cross-shaped component is similar to the residual stress distribution of thick plate, the large tensile stress concentration is exist in web plate and the connection part of the stiffener with a certain influence area. The error data of the component contour deformation were processed and the component deformation contour was fitted, which makes the test result of the contour method and FE simulation result have good consistency. The results of the study provides guidance for quenching residual stress reduction of aviation aluminum alloy components and provides the basis for calculating of machining deformation of monolithic component.

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Shinmura, Ken. „Effects of Caloric Restriction on Cardiac Oxidative Stress and Mitochondrial Bioenergetics: Potential Role of Cardiac Sirtuins“. Oxidative Medicine and Cellular Longevity 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/528935.

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The biology of aging has not been fully clarified, but the free radical theory of aging is one of the strongest aging theories proposed to date. The free radical theory has been expanded to the oxidative stress theory, in which mitochondria play a central role in the development of the aging process because of their critical roles in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function associated with the accumulation of oxidative damage might be responsible, at least in part, for the decline in cardiac performance with age. In contrast, lifelong caloric restriction can attenuate functional decline with age, delay the onset of morbidity, and extend lifespan in various species. The effect of caloric restriction appears to be related to a reduction in cellular damage induced by reactive oxygen species. There is increasing evidence that sirtuins play an essential role in the reduction of mitochondrial oxidative stress during caloric restriction. We speculate that cardiac sirtuins attenuate the accumulation of oxidative damage associated with age by modifying specific mitochondrial proteins posttranscriptionally. Therefore, the distinct role of each sirtuin in the heart subjected to caloric restriction should be clarified to translate sirtuin biology into clinical practice.

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Snow, David. „A Prominence Account of Syllable Reduction in Early Speech Development“. Journal of Speech, Language, and Hearing Research 41, Nr. 5 (Oktober 1998): 1171–84. http://dx.doi.org/10.1044/jslhr.4105.1171.

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When young children produce multiword utterances and words that are polysyllabic in adult speech, they are most likely to omit unstressed syllables. Because unstressed syllables are omitted more often in weak-strong (iambic) than in strong-weak (trochaic) environments, a trochaic metrical theory has been proposed to account for the asymmetrical omission pattern. This paper presents an alternative explanation based on the notion of relative prosodic prominence. I propose that syllable prominence is a product of two orthogonal suprasegmental systems: one that marks stress/accent peaks and one that marks phrase boundaries. A two-component scale of prominence values reflecting the contributions of both systems was used to analyze single- and multi-word speech samples of 11 children 19 to 26 months of age. The results show that the prominence scale parsimoniously accounts not only for the bias toward syllable omissions in nontrochaic environments but also explains other types of syllable reduction not captured by metrical theories. Implications of the dual-system prosodic model are discussed in terms of possible contributions to a perceptually based theory of early polysyllabic and multiword patterns in child speech.

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Sadiq, Taoheed O., Taiwo G. Fadara, Peter O. Aiyedun und Jamaliah Idris. „Numerical Estimation of Rolling Load and Torque for Hot Flat Rolling of HCSS316 at Low Strain Rates Based on Mean Temperature“. International Journal of Engineering Research in Africa 26 (Oktober 2016): 11–29. http://dx.doi.org/10.4028/www.scientific.net/jera.26.11.

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Numerical estimation of rolling load and torque often showed large discrepancies when compared with experimental values. This was attributed to difficulty in estimating the mean rolling temperature from the available data. This work is thus directed at obtaining a good estimate for the mean rolling temperature which can effectively be used for load and torque estimates. Hot flat rolling stimulation by use of the Bland and Ford’s cold rolling (HRBF) theory confirmed the reverse sandwich effect in selected carbon steels at low strain rates. In this work, the effect of pass reduction on rolling temperature distribution, yield stress and rolling load were studied for AISI Type 316 stainless steel (HSCSS316). For this new simulation, at low and high strain rates, results showed that the ratio of experimental to calculated rolling load and torque were higher at lower reduction than at higher reduction. These results confirmed excess load and torque in the hot rolling of HSCSS316 low reductions. The results obtained from Hot Rolling Bland and Ford’s Theory based on Root Mean Square rolling temperature were in good agreement with values obtained using Reverse Sandwich Model and the Reverse Sandwich- Hot Rolling Bland and Ford’s Program under the same rolling conditions.

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Liu, Sheng Chuan. „Study on Stability of High Embankment with Strong Weathering Filling under Complicated Stress Conditions“. Applied Mechanics and Materials 97-98 (September 2011): 78–84. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.78.

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Strength reduction elasto-plastic finite element analysis defines the reduction factor when slope has been destroyed as the slope stability factor of safety, which combines with strength reduction technique, the limit equilibrium theory and the principle of elastic-plastic finite element. Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.

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Lin, Sheng, Xian Fen Xu, Cheng Wang und Jian Xin Ye. „Analysis of Creep and Shrinkage Mechanism of Bridge Considering the Effect of Shrinkage on Creep Stress Reduction“. Advanced Materials Research 255-260 (Mai 2011): 781–85. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.781.

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The effect of concrete shrinkage and creep on the deformation of the bridge structure is posing a serious issue with increasing numbers of large-span bridges are being built. At the moment, only the creep coefficient is usually considered for calculating bridge creep, without taking other factors into consideration. This paper, based on aging theory, considers the influence of shrinkage on creep stress reduction, by simplifying the formula of creep strain under discrete load by using the integral mean-value theorem and deriving the formula of concrete creep strain. Taking a continuous rigid frame bridge for example, the paper calculated the creep considering creep stress reduction under shrinkage, which showed that the method can well predict the final shrinkage and creep values of large-span concrete bridge.

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Wang, Feng Hui, Kang Lou und Yong Jun Wang. „Effect of Residual Stresses on Bending Test in Bilayer of SOFC“. Applied Mechanics and Materials 83 (Juli 2011): 104–8. http://dx.doi.org/10.4028/www.scientific.net/amm.83.104.

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When to test the failure stress of Solid Oxide Fuel Cell system, bending approach is consider as one of the convenient ways. The failure stresses are calculated by the elasticity multi -layered theory, in which the neutral axis is determined by the mechanical properties of materials and the thickness of the layers. When cooling from the sintered temperature, residual stresses arise in the multi-layered system due to the mismatch of the thermal expansion coefficients, in this case, the thermal elastic theory point out that the neutral axis depends on residual stress. In this paper, the effect of residual stress on the shift of neutral axis and consequently the failure stress of SOFCs presented, the finite element method was also employed to calculate the SOFCs before and after reduction. The results show that the residual stresses has a distribution along the thickness of the layers, the neutral axis also shifts with the residual stress and the external bending moment, when to test and value the bending stress, the shift of neutral axis should be considered.

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Iverson, Neal R. „Laboratory Simulations Of Glacial Abrasion: Comparison With Theory“. Journal of Glaciology 36, Nr. 124 (1990): 304–14. http://dx.doi.org/10.3189/002214390793701264.

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AbstractGlacial abrasion was simulated in experiments in which a small artificial glacier bed was pushed beneath a fixed ice block under pressure. The experiments provide a means of testing theoretical models of abrasion, particularly those factors that govern the magnitude of stress concentrations beneath abrading rock fragments. In preliminary experiments, vertical ice flow around a sphere mounted on the bed was studied. In subsequent experiments, marble tablets were pushed beneath granitic rock fragments frozen into the base of the ice block. Unlike previous abrasion experiments, the sliding velocity was realistic (25 mm d−1), and ice near the bed was at the pressure-melting temperature. Resultant striations closely resemble those observed on glaciated bedrock.As predicted by Hallet (1979), the component of the ice velocity towards the bed strongly influenced stresses beneath fragments, and classical regelation and creep theory provided an approximate estimate of the downward drag force on fragments. Half of the rock fragments rotated significantly, accounting for 10–50% of their motion relative to the bed and influencing abrasion rates and the shear stress supported along the ice-bed interface. Striation patterns indirectly suggest that fragment rotations were inhibited by increases in ice pressure, which presumably increased the drag on roughness elements on fragment surfaces. This may have resulted from a reduction in the thickness of the water film around fragments, facilitated by leakage of water from the bed.

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Zhang, Zhao Qiang, und Yong Yao. „Analysis on Bearing Capacity of Solid Multibarrel Tube-Confined Concrete Short Columns (CHS Inner and SHS Outer) under Axial Compressive Load“. Advanced Materials Research 255-260 (Mai 2011): 151–56. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.151.

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By introducing the reduction coefficient of concrete strength and the equivalent restriction reduction coefficient,the non-uniform confinement force of square steel tube to its core concrete is turned to that of equivalent circular steel tube. Then the ultimate load calculation formula for the solid multibarrel tube-confined concrete short columns (CHS inner and SHS outer) is derived based on the Unified Strength Theory(UST),in which the double restriction effect and the decrease of longitudinal stress because of the hoop tensile tension are considered. The influence of intermediate principal stress on the ultimate load is studied and the failure mechanism is discussed. The applicability of the formulas is testified and the results show that the formulas have significance in exerting material potential.

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