WorldWideScience

Sample records for macroscopic stress-stress correlation

  1. Linking stress with macroscopic and microscopic leaf response in trees: New diagnostic perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Guenthardt-Goerg, Madeleine S. [Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, Zuercherstrasse 111, CH-8903 Birmensdorf (Switzerland)]. E-mail: madeleine.goerg@wsl.ch; Vollenweider, Pierre [Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, Zuercherstrasse 111, CH-8903 Birmensdorf (Switzerland)

    2007-06-15

    Visible symptoms in tree foliage can be used for stress diagnosis once validated with microscopical analyses. This paper reviews and illustrates macroscopical and microscopical markers of stress with a biotic (bacteria, fungi, insects) or abiotic (frost, drought, mineral deficiency, heavy metal pollution in the soil, acidic deposition and ozone) origin helpful for the validation of symptoms in broadleaved and conifer trees. Differentiation of changes in the leaf or needle physiology, through ageing, senescence, accelerated cell senescence, programmed cell death and oxidative stress, provides additional clues raising diagnosis efficiency, especially in combination with information about the target of the stress agent at the tree, leaf/needle, tissue, cell and ultrastructural level. Given the increasing stress in a changing environment, this review discusses how integrated diagnostic approaches lead to better causal analysis to be applied for specific monitoring of stress factors affecting forest ecosystems. - Macroscopic leaf symptoms and their microscopic analysis as stress bioindications.

  2. Linking stress with macroscopic and microscopic leaf response in trees: New diagnostic perspectives

    International Nuclear Information System (INIS)

    Guenthardt-Goerg, Madeleine S.; Vollenweider, Pierre

    2007-01-01

    Visible symptoms in tree foliage can be used for stress diagnosis once validated with microscopical analyses. This paper reviews and illustrates macroscopical and microscopical markers of stress with a biotic (bacteria, fungi, insects) or abiotic (frost, drought, mineral deficiency, heavy metal pollution in the soil, acidic deposition and ozone) origin helpful for the validation of symptoms in broadleaved and conifer trees. Differentiation of changes in the leaf or needle physiology, through ageing, senescence, accelerated cell senescence, programmed cell death and oxidative stress, provides additional clues raising diagnosis efficiency, especially in combination with information about the target of the stress agent at the tree, leaf/needle, tissue, cell and ultrastructural level. Given the increasing stress in a changing environment, this review discusses how integrated diagnostic approaches lead to better causal analysis to be applied for specific monitoring of stress factors affecting forest ecosystems. - Macroscopic leaf symptoms and their microscopic analysis as stress bioindications

  3. Prediction of macroscopic and local stress-strain behaviors of perforated plates under primary and secondary creep conditions

    International Nuclear Information System (INIS)

    Igari, Toshihide; Tokiyoshi, Takumi; Mizokami, Yorikata

    2000-01-01

    Prediction methods of macroscopic and local creep behaviors of perforated plates are examined in order to apply these methods to the structural design of perforated structures such as heat exchangers used in elevated temperatures. Both primary and secondary creeps are considered for predicting macroscopic and local creep behaviors of perorated plates which are made of actual structural materials. Both uniaxial and multiaxial loading of perforated plates are taken into consideration. The concept of effective stress is applied to the prediction of macroscopic creep behaviors of perforated plates, and the predicted results are compared with the numerical results by FEM for the unit section of perorated plated under creep, in order to confirm the propriety of the proposed method. Based on the idea that stress exponents in creep equations govern the stress distribution of perforated plates, a modified Neuber's rule is used for predicting local stress and strain concentrations. The propriety of this prediction method is shown through a comparison of the prediction with the numerical results by FEM for the unit section of perforated plates under creep, and experimental results by the Moire method. (author)

  4. Macroscopic electrical field distribution and field-induced surface stresses of needle-shaped field emitters

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    Moy, Charles K.S., E-mail: charles.moy@sydney.edu.au [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, The University of Sydney, Sydney, NSW 2006 (Australia); School of Civil Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Ranzi, Gianluca [ARC Centre of Excellence for Design in Light Metals, The University of Sydney, Sydney, NSW 2006 (Australia); School of Civil Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Petersen, Timothy C. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Ringer, Simon P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, The University of Sydney, Sydney, NSW 2006 (Australia)

    2011-05-15

    One major concern since the development of the field ion microscope is the mechanical strength of the specimens. The macroscopic shape of the imaging tip greatly influences field-induced stresses and there is merit in further study of this phenomenon from a classical perspective. Understanding the geometrical, as opposed to localized electronic, factors that affect the stress might improve the quality and success rate of atom probe experiments. This study uses macroscopic electrostatic principles and finite element modelling to investigate field-induced stresses in relation to the shape of the tip. Three two-dimensional idealized models are considered, namely hyperbolic, parabolic and sphere-on-orthogonal-cone; the shapes of which are compared to experimental tips prepared by electro-polishing. Three dimensional morphologies of both a nano-porous and single-crystal aluminium tip are measured using electron tomography to quantitatively test the assumption of cylindrical symmetry for electro-polished tips. The porous tip was prepared and studied to demonstrate a fragile specimen for which such finite element studies could determine potential mechanical failure, prior to any exhaustive atom probe investigation. -- Research highlights: {yields} We use electrostatic principles and finite element to model field-induced stresses. {yields} We study two-dimensional idealized needle-shaped field emitters. {yields} Stress distribution of hyperbolic, parabolic and sphere-on-orthogonal-cone tips mapped. {yields} Electron tomography to obtain the morphology of three-dimensional aluminium tips. {yields} Studies of the morphology of the porous tip demonstrate a fragile specimen.

  5. Antiferromagnetic character of workplace stress

    Science.gov (United States)

    Watanabe, Jun-Ichiro; Akitomi, Tomoaki; Ara, Koji; Yano, Kazuo

    2011-07-01

    We study the nature of workplace stress from the aspect of human-human interactions. We investigated the distribution of Center for Epidemiological Studies Depression Scale scores, a measure of the degree of stress, in workplaces. We found that the degree of stress people experience when around other highly stressed people tends to be low, and vice versa. A simulation based on a model describing microlevel human-human interaction reproduced this observed phenomena and revealed that the energy state of a face-to-face communication network correlates with workplace stress macroscopically.

  6. Microstructure and temperature dependence of intergranular strains on diffractometric macroscopic residual stress analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.N., E-mail: Julia.Wagner@kit.edu [KNMF, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Hofmann, M. [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), TU München, Lichtenbergstr. 1, 85747 Garching (Germany); Wimpory, R. [Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin Wannsee (Germany); Krempaszky, C. [Christian-Doppler-Labor für Werkstoffmechanik von Hochleistungslegierungen, TU München, Boltzmannstr. 15, 85747 Garching (Germany); Lehrstuhl für Werkstoffkunde und Werkstoffmechanik, TU München, Boltzmannstr. 15, 85747 Garching (Germany); Stockinger, M. [Böhler Schmiedetechnik GmbH and Co KG, Mariazeller Straße 25, 8605 Kapfenberg (Austria)

    2014-11-17

    Knowledge of the macroscopic residual stresses in components of complex high performance alloys is crucial when it comes to considering the safety and manufacturing aspects of components. Diffraction experiments are one of the key methods for studying residual stresses. However a component of the residual strain determined by diffraction experiments, known as microstrain or intergranular residual strain, occurs over the length scale of the grains and thus plays only a minor role for the life time of such components. For the reliable determination of macroscopic strains (with the minimum influence of these intergranular residual strains), the ISO standard recommends the use of particular Bragg reflections. Here we compare the build-up of intergranular strain of two different precipitation hardened IN 718 (INCONEL 718) samples, with identical chemical composition. Since intergranular strains are also affected by temperature, results from room temperature measurement are compared to results at T=550 °C. It turned out that microstructural parameters, such as grain size or type of precipitates, have a larger effect on the intergranular strain evolution than the influence of temperature at the measurement temperature of T=550 °C. The results also show that the choice of Bragg reflections for the diffractometric residual stress analysis is dependent not only on its chemical composition, but also on the microstructure of the sample. In addition diffraction elastic constants (DECs) for all measured Bragg reflections are given.

  7. An Investigation of the Correlation among Sources of Stress, Perceived Stress, and Coping styles in High School Students

    Directory of Open Access Journals (Sweden)

    Farhadh Asghari

    2016-07-01

    Full Text Available Background and Objectives: Coping with stress is an important issue, especially in regard to source of stress and perceived stress in adolescence period. In this research, the correlation among stress sources, perceived stress, and coping styles was investigated in high school students. Methods: The present research was a descriptive correlational study. The research sample consisted of 575 high school students from the families of personnel of Bushehr University of Medical Sciences in education year 2014-15 who were selected by multistage cluster sampling method. Stress source scale, perceived stress scale and Tehran coping styles scale, were used for data collection. The data were analyzed using statistical methods, including Pearson correlation coefficient and multivariate regression analysis. Results: In this study, 50% of students had perceived stress higher than cut-off point. Stress sources of students were related to school and maturity. There was a positive correlation between problem-oriented coping style and perceived stress, and there was a negative and inverse correlation between problem-oriented coping style and stress related to school and maturity. There was a positive correlation between positive emotion-oriented coping style and perceived stress, but there was a negative and inverse correlation between problem-oriented coping style and stress related to school and maturity. There was no significant correlation between emotion-oriented coping style and stress related to school, maturity, family, and peers. There was a positive correlation between negative emotion-oriented coping style and stress related to school, maturity, and peers. Conclusion: According to the findings of this study, the level of correlation was not significant and no significant relationship could be found between the variables with this level of correlation. Therefore, it is suggested that more extensive researches be conducted on the relationship between

  8. General quantitative analysis of stress partitioning and boundary conditions in undrained biphasic porous media via a purely macroscopic and purely variational approach

    Science.gov (United States)

    Serpieri, Roberto; Travascio, Francesco

    2016-03-01

    In poroelasticity, the effective stress law relates the external stress applied to the medium to the macroscopic strain of the solid phase and the interstitial pressure of the fluid saturating the mixture. Such relationship has been formerly introduced by Terzaghi in form of a principle. To date, no poroelastic theory is capable of recovering a stress partitioning law in agreement with Terzaghi's postulated one in the absence of ad hoc constitutive assumptions on the medium. We recently proposed a variational macroscopic continuum description of two-phase poroelasticity to derive a general biphasic formulation at finite deformations, termed variational macroscopic theory of porous media (VMTPM). Such approach proceeds from the inclusion of the intrinsic volumetric strain among the kinematic descriptors aside to macroscopic displacements, and as a variational theory, uses the Hamilton least-action principle as the unique primitive concept of mechanics invoked to derive momentum balance equations. In a previous related work it was shown that, for the subclass of undrained problems, VMTPM predicts that stress is partitioned in the two phases in strict compliance with Terzaghi's law, irrespective of the microstructural and constitutive features of a given medium. In the present contribution, we further develop the linearized framework of VMTPM to arrive at a general operative formula that allows the quantitative determination of stress partitioning in a jacketed test over a generic isotropic biphasic specimen. This formula is quantitative and general, in that it relates the partial phase stresses to the externally applied stress as function of partitioning coefficients that are all derived by strictly following a purely variational and purely macroscopic approach, and in the absence of any specific hypothesis on the microstructural or constitutive features of a given medium. To achieve this result, the stiffness coefficients of the theory are derived by using

  9. Neutron-diffraction measurements of stress

    International Nuclear Information System (INIS)

    Holden, T.M.

    1995-01-01

    Experiments on bent steam-generator tubing have shown that different diffraction peaks, (1 1 1) or (0 0 2), give different results for the sign and magnitude of the stress and strain. From an engineering standpoint, the macroscopic stress field cannot be both positive and negative in the same volume, so this difference must be due to intergranular effects superposed on the macroscopic stress field. Uniaxial tensile test experiments with applied stresses beyond the 0.2% offset yield stress, help to understand this anomaly, by demonstrating the different strain response to applied stress along different crystallographic axes.When Zr-alloys are cooled from elevated temperatures, thermal stresses always develop, so that it is difficult to obtain a stress-free lattice spacing from which residual strains may be derived. From measurements of the temperature dependence of lattice spacing, the temperature at which the thermal stresses vanish may be found. From the lattice spacing at this temperature the stress-free lattice spacings at room temperature can be obtained readily.To interpret the measured strains in terms of macroscopic stress fields it is necessary to know the diffraction elastic constants. Neutron diffraction measurements of the diffraction elastic constants in a ferritic steel for the [1 1 0], [0 0 2] and [2 2 2] crystallographic axes, in directions parallel and perpendicular to the applied stress are compared with theoretical diffraction elastic constants. (orig.)

  10. Macroscopic and microscopic determinations of residual stresses in thin oxide dispersion strengthened steel tubes

    International Nuclear Information System (INIS)

    Bechade, J.L.; Toualbi, L.; Bosonnet, S.; Carlan, Y. de; Castelnau, O.

    2014-01-01

    To improve the efficiency of components operating at high temperatures, many efforts are deployed to develop new materials. Oxide Dispersion Strengthened (ODS) materials could be used for heat exchangers or cladding tubes for the new GENIV nuclear reactors. This type of materials are composed with a metallic matrix (usually iron base alloy for nuclear applications or nickel base alloy for heat exchangers) reinforced by a distribution of nano-oxides. They are obtained by powder metallurgy and mechanical alloying. The creep resistance of these materials is excellent, and they usually exhibit a high tensile strength at room temperature. Depending on the cold working and/or the heat treatments, several types of microstructure can be obtained: recrystallised, stress relieved. One of the key challenges is to transform ODS materials into thin tubes (up to 500 microns thick) within a robust fabrication route while keeping the excellent mechanical properties. To prevent cracking during the process or to obtain a final product with low residual stresses, it is important to quantify the effect of the heat treatments on the release of internal stresses. The aim of this study is to show how residual stresses can be determined on different thin tubes using two complementary approaches: (i) macroscopic stresses determination in the tube using beam theory (small cuts along the longitudinal and circumferential directions and measurements of the deflection), (ii) stress determination from x-ray diffraction analyses (surface analyses, using 'sin"2ψ' method with different hypothesis). Depending on the material and the heat treatment, residual stresses vary dramatically and can reach 800 MPa which is not far from the yield stress; comparisons between both methods are performed and suggestions are given in order to optimize the thermo-mechanical treatment of thin ODS tubes. (authors)

  11. Contribution to viscosity from the structural relaxation via the atomic scale Green-Kubo stress correlation function

    Science.gov (United States)

    Levashov, V. A.

    2017-11-01

    We studied the connection between the structural relaxation and viscosity for a binary model of repulsive particles in the supercooled liquid regime. The used approach is based on the decomposition of the macroscopic Green-Kubo stress correlation function into the correlation functions between the atomic level stresses. Previously we used the approach to study an iron-like single component system of particles. The role of vibrational motion has been addressed through the demonstration of the relationship between viscosity and the shear waves propagating over large distances. In our previous considerations, however, we did not discuss the role of the structural relaxation. Here we suggest that the contribution to viscosity from the structural relaxation can be taken into account through the consideration of the contribution from the atomic stress auto-correlation term only. This conclusion, however, does not mean that only the auto-correlation term represents the contribution to viscosity from the structural relaxation. Previously the role of the structural relaxation for viscosity has been addressed through the considerations of the transitions between inherent structures and within the mode-coupling theory by other authors. In the present work, we study the structural relaxation through the considerations of the parent liquid and the atomic level stress correlations in it. The comparison with the results obtained on the inherent structures also is made. Our current results suggest, as our previous observations, that in the supercooled liquid regime, the vibrational contribution to viscosity extends over the times that are much larger than the Einstein's vibrational period and much larger than the times that it takes for the shear waves to propagate over the model systems. Besides addressing the atomic level shear stress correlations, we also studied correlations between the atomic level pressure elements.

  12. Correlates of housing affordability stress among older Australians.

    Science.gov (United States)

    Temple, Jeromey B

    2008-03-01

    The purpose of this study was to examine the prevalence and correlates of housing affordability stress among community-dwelling older Australians. The 2002 ABS General Social Survey was used to measure the prevalence of housing affordability stress. Rare event logistic regression was used to measure the potential correlates of housing affordability stress. Almost 5% of Australians aged 55 years and older, and 20% of those younger than 55 years, are estimated to experience housing affordability stress. Men and women living alone are more likely to experience affordability stress when compared to couples. Low-income earners, those with a consumer debt or who do not hold assets, are at a heightened risk of such stress. Home ownership, regardless of income, is the strongest buffer against housing affordability problems in old age. Although the prevalence of housing affordability stress is low among older Australians when compared to the younger population, a definite social gradient exists in those at risk.

  13. Frequency and Wavevector Dependence of the Atomic Level Stress-Stress Correlation Function in a Model Supercooled Liquid

    Science.gov (United States)

    Levashov, Valentin A.; Morris, James R.; Egami, Takeshi

    2012-02-01

    Temporal and spatial correlations among the local atomic level shear stresses were studied for a model liquid iron by molecular dynamics simulation [PRL 106,115703]. Integration over time and space of the shear stress correlation function F(r,t) yields viscosity via Green-Kubo relation. The stress correlation function in time and space F(r,t) was Fourier transformed to study the dependence on frequency, E, and wave vector, Q. The results, F(Q,E), showed damped shear stress waves propagating in the liquid for small Q at high and low temperatures. We also observed additional diffuse feature that appears as temperature is reduced below crossover temperature of potential energy landscape at relatively low frequencies at small Q. We suggest that this additional feature might be related to dynamic heterogeneity and boson peaks. We also discuss a relation between the time-scale of the stress-stress correlation function and the alpha-relaxation time of the intermediate self-scattering function S(Q,E).

  14. Averaging problem in general relativity, macroscopic gravity and using Einstein's equations in cosmology.

    Science.gov (United States)

    Zalaletdinov, R. M.

    1998-04-01

    The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the geometry of macroscopic space-time, which follows from averaging Cartan's structure equations, is described and the correlation tensors present in the theory are discussed. The macroscopic field equations (averaged Einstein's equations) derived in the framework of the approach are presented and their structure is analysed. The correspondence principle for macroscopic gravity is formulated and a definition of the stress-energy tensor for the macroscopic gravitational field is proposed. It is shown that the physical meaning of using Einstein's equations with a hydrodynamic stress-energy tensor in looking for cosmological models means neglecting all gravitational field correlations. The system of macroscopic gravity equations to be solved when the correlations are taken into consideration is given and described.

  15. Consistent stress-strain ductile fracture model as applied to two grades of beryllium

    International Nuclear Information System (INIS)

    Priddy, T.G.; Benzley, S.E.; Ford, L.M.

    1980-01-01

    Published yield and ultimate biaxial stress and strain data for two grades of beryllium are correlated with a more complete method of characterizing macroscopic strain at fracture initiation in ductile materials. Results are compared with those obtained from an exponential, mean stress dependent, model. Simple statistical methods are employed to illustrate the degree of correlation for each method with the experimental data

  16. Long range stress correlations in the inherent structures of liquids at rest

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Sadrul; Abraham, Sneha; Hudson, Toby; Harrowell, Peter [School of Chemistry, University of Sydney, Sydney, NSW 2006 (Australia)

    2016-03-28

    Simulation studies of the atomic shear stress in the local potential energy minima (inherent structures) are reported for binary liquid mixtures in 2D and 3D. These inherent structure stresses are fundamental to slow stress relaxation and high viscosity in supercooled liquids. We find that the atomic shear stress in the inherent structures (IS’s) of both liquids at rest exhibits slowly decaying anisotropic correlations. We show that the stress correlations contribute significantly to the variance of the total shear stress of the IS configurations and consider the origins of the anisotropy and spatial extent of the stress correlations.

  17. Relationship between Structural and Stress Relaxation in a Block-Copolymer Melt

    International Nuclear Information System (INIS)

    Patel, Amish J.; Narayanan, Suresh; Sandy, Alec; Mochrie, Simon G. J.; Garetz, Bruce A.; Watanabe, Hiroshi; Balsara, Nitash P.

    2006-01-01

    The relationship between structural relaxation on molecular length scales and macroscopic stress relaxation was explored in a disordered block-copolymer melt. Experiments show that the structural relaxation time, measured by x-ray photon correlation spectroscopy is larger than the terminal stress relaxation time, measured by rheology, by factors as large as 100. We demonstrate that the structural relaxation data are dominated by the diffusion of intact micelles while the stress relaxation data are dominated by contributions due to disordered concentration fluctuations

  18. Stress-affected microstructural development and creep-swelling interrelationship

    International Nuclear Information System (INIS)

    Brager, H.R.; Garner, F.A.; Gilbert, E.R.; Flinn, J.E.; Wolfer, W.G.

    1977-05-01

    Macroscopic measurement of the deformations arising from swelling and creep during neutron irradiation indicate that both processes are dependent on the magnitude and possibly the sign of the applied stress state. Current modeling efforts also indicate that a strong interaction exists between swelling and creep through the stress state. Because the macroscopic distortions arise from the integrated microscopic strains associated with specific microstructural elements, the effect of applied stress on microstructural development has been studied

  19. Stress induced reorientation of vanadium hydride

    International Nuclear Information System (INIS)

    Beardsley, M.B.

    1977-10-01

    The critical stress for the reorientation of vanadium hydride was determined for the temperature range 180 0 to 280 0 K using flat tensile samples containing 50 to 500 ppM hydrogen by weight. The critical stress was observed to vary from a half to a third of the macroscopic yield stress of pure vanadium over the temperature range. The vanadium hydride could not be stress induced to precipitate above its stress-free precipitation temperature by uniaxial tensile stresses or triaxial tensile stresses induced by a notch

  20. Iodine-induced stress corrosion cracking of fixed deflection stressed slotted rings of Zircaloy fuel cladding

    International Nuclear Information System (INIS)

    Sejnoha, R.; Wood, J.C.

    1978-01-01

    Stress corrosion cracking of Zircaloy fuel cladding by fission products is thought to be an important mechanism influencing power ramping defects of water-reactor fuels. We have used the fixed-deflection stressed slotted-ring technique to demonstrate cracking. The results show both the sensitivity and limitations of the stressed slotted-ring method in determining the responses of tubing to stress corrosion cracking. They are interpreted in terms of stress relaxation behavior, both on a microscopic scale for hydrogen-induced stress-relief and on a macroscopic scale for stress-time characteristics. Analysis also takes account of nonuniform plastic deformation during loading and residual stress buildup on unloading. 27 refs

  1. Correlation Between the Microstructural Defects and Residual Stress in a Single Crystal Nickel-Based Superalloy During Different Creep Stages

    Science.gov (United States)

    Mo, Fangjie; Wu, Erdong; Zhang, Changsheng; Wang, Hong; Zhong, Zhengye; Zhang, Jian; Chen, Bo; Hofmann, Michael; Gan, Weimin; Sun, Guangai

    2018-03-01

    The present work attempts to reveal the correlation between the microstructural defects and residual stress in the single crystal nickel-based superalloy, both of which play the significant role on properties and performance. Neutron diffraction was employed to investigate the microstructural defects and residual stresses in a single crystal (SC) nickel-based superalloy, which was subjected to creeping under 220 MPa and 1000 °C for different times. The measured superlattice and fundamental lattice reflections confirm that the mismatch and tetragonal distortions with c/a > 1 exist in the SC superalloy. At the initially unstrained state, there exists the angular distortion between γ and γ' phases with small triaxial compressive stresses, ensuring the structural stability of the superalloy. After creeping, the tetragonal distortion for the γ phase is larger than that for the γ' phase. With increasing the creeping time, the mismatch between γ and γ' phases increases to the maximum, then decreases gradually and finally remains unchanged. The macroscopic residual stress shows a similar behavior with the mismatch, indicating the correlation between them. Based on the model of shear and dislocations, the evolution of microstructural defects and residual stress are reasonably explained. The effect of shear is dominant at the primary creep stage, which greatly enlarges the mismatch and the residual stress. The dislocations weaken the effect of shear for the further creep stage, resulting in the decrease of the mismatch and relaxation of the residual stress. Those findings add some helpful understanding into the microstructure-performance relationship in the SC nickel-based superalloy, which might provide the insight to materials design and applications.

  2. Plastic incompatibility stresses and stored elastic energy in plastically deformed copper

    Energy Technology Data Exchange (ETDEWEB)

    Baczmanski, A. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland)], E-mail: baczman@ftj.agh.edu.pl; Hfaiedh, N.; Francois, M. [LASMIS, Universite de Technologie de Troyes, 11 rue Marie Curie, B.P. 2060, 10010 Troyes (France); Wierzbanowski, K. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland)

    2009-02-15

    The X-ray diffraction method and theoretical model of elastoplastic deformation were used to examine the residual stresses in polycrystalline copper. To this end, the {l_brace}2 2 0{r_brace} strain pole figures were determined for samples subjected to different magnitudes of tensile deformation. Using diffraction data and the self-consistent model, the tensor of plastic incompatibility stress was found for each orientation of a polycrystalline grain. Crystallographic textures, macroscopic and second-order residual stresses were considered in the analysis. As a result, the distributions of elastic stored energy and von Mises equivalent stress were presented in Euler space and correlated with the preferred orientations of grains. Moreover, using the model prediction, the variation of the critical resolved shear stress with grain orientation was determined.

  3. Stress relaxation in a ferrofluid with clustered nanoparticles

    International Nuclear Information System (INIS)

    Borin, Dmitry Yu; Odenbach, Stefan; Zubarev, Andrey Yu; Chirikov, Dmitry N

    2014-01-01

    The formation of structures in a ferrofluid by an applied magnetic field causes various changes in the rheological behaviour of the ferrofluid. A ferrofluid based on clustered iron nanoparticles was investigated. We experimentally and theoretically consider stress relaxation in the ferrofluid under the influence of a magnetic field, when the flow is suddenly interrupted. It is shown that the residual stress observed in the fluid after the relaxation is correlated with the measured and theoretically predicted magnetic field-induced yield stress. Furthermore, we have shown that the total macroscopic stress in the ferrofluid after the flow is interrupted is defined by the presence of both linear chains and dense, drop-like bulk aggregates. The proposed theoretical approach is consistent with the experimentally observed behaviour, despite a number of simplifications which have been made in the formulation of the model. Thus, the obtained results contribute a lot to the understanding of the complex, magnetic field-induced rheological properties of magnetic colloids near the yield stress point. (paper)

  4. Correlation between Occupational Stress and Burnout in Rehabilitation Center Employees of Kashan, Iran

    Directory of Open Access Journals (Sweden)

    Sarsangi V.* MSc,

    2015-01-01

    Full Text Available Aims Stress is considered as a psychological phenomenon that inflicts human beings in the modern societies. Burnout is a psychological or behavioral state which occurs as individual’s performance quality deteriorates. This study aimed to investigate the level of burnout and occupational stress in Kashan rehabilitating centers staffs. Materials & Methods This descriptive study was done on all 298 nurse assistants of Kashan rehabilitation centers in 2013. Data collected using “Health and Safety Executive Questionnaire (HSE” and “Maslach burnout inventory (MBI”. Data were analyzed by the Excel and SPSS 16 software. Pearson correlation coefficient was used to assess relationship between stress dimension and occupation burnout factors. Findings The average of occupational stress was 3.65±0.51 and the average of burnout was 29.67±4.38. Occupational groups had no significant correlation with occupational stress (p=0.86 but had a significant correlation with burnout (p=0.006. There were significant positive correlations between occupational stress parameters and burnout parameters. Just the peer support of occupational stress had no correlations with success, emotional exhaustion and general burnout. Conclusion Deterioration of stressful parameters in occupational environment can mitigate damaging effects of burnout syndromes.

  5. Modeling of stresses at grain boundaries with respect to occurrence of stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Kozaczek, K.J. [Oak Ridge National Lab., TN (United States); Sinharoy, A.; Ruud, C.O. [Pennsylvania State Univ., University Park, PA (United States); McIlree, A.R. [Electric Power Research Institute, Palo Alto, CA (United States)

    1995-12-31

    The distributions of elastic stresses/strains in the grain boundary regions were studied by the analytical and the finite element models. The grain boundaries represent the sites where stress concentration occurs as a result of discontinuity of elastic properties across the grain boundary and the presence of second phase particles elastically different from the surrounding matrix grains. A quantitative analysis of those stresses for steels and nickel based alloys showed that the stress concentrations in the grain boundary regions are high enough to cause a local microplastic deformation even when the material is in the macroscopic elastic regime. The stress redistribution as a result of such a plastic deformation was discussed.

  6. Correlation Between Fracture Network Properties and Stress Variability in Geological Media

    Science.gov (United States)

    Lei, Qinghua; Gao, Ke

    2018-05-01

    We quantitatively investigate the stress variability in fractured geological media under tectonic stresses. The fracture systems studied include synthetic fracture networks following power law length scaling and natural fracture patterns based on outcrop mapping. The stress field is derived from a finite-discrete element model, and its variability is analyzed using a set of mathematical formulations that honor the tensorial nature of stress data. We show that local stress perturbation, quantified by the Euclidean distance of a local stress tensor to the mean stress tensor, has a positive, linear correlation with local fracture intensity, defined as the total fracture length per unit area within a local sampling window. We also evaluate the stress dispersion of the entire stress field using the effective variance, that is, a scalar-valued measure of the overall stress variability. The results show that a well-connected fracture system under a critically stressed state exhibits strong local and global stress variabilities.

  7. Growth stress buildup in ion beam sputtered Mo thin films and comparative study of stress relaxation upon thermal annealing or ion irradiation

    International Nuclear Information System (INIS)

    Debelle, A.; Abadias, G.; Michel, A.; Jaouen, C.; Pelosin, V.

    2007-01-01

    In an effort to address the understanding of the origin of growth stress in thin films deposited under very energetic conditions, the authors investigated the stress state and microstructure of Mo thin films grown by ion beam sputtering (IBS) as well as the stress relaxation processes taking place during subsequent thermal annealing or ion irradiation. Different sets of samples were grown by varying the IBS deposition parameters, namely, the energy E 0 and the flux j of the primary ion beam, the target-to-sputtering gas mass ratio M 1 /M 2 as well as film thickness. The strain-stress state was determined by x-ray diffraction using the sin 2 ψ method and data analyzed using an original stress model which enabled them to correlate information at macroscopic (in terms of stress) and microscopic (in terms of defect concentration) levels. Results indicate that these refractory metallic thin films are characterized by a high compressive growth stress (-2.6 to -3.8 GPa), resulting from the creation of a large concentration (up to ∼1.4%) of point or cluster defects, due to the atomic peening mechanism. The M 1 /M 2 mass ratio enables tuning efficiently the mean deposited energy of the condensing atoms; thus, it appears to be the more relevant deposition parameter that allows modifying both the microstructure and the stress level in a significant way. The growth stress comes out to be highly unstable. It can be easily relaxed either by postgrowth thermal annealing or ion irradiation in the hundred keV range at very low dose [<0.1 dpa (displacement per atom)]. It is shown that thermal annealing induces deleterious effects such as oxidation of the film surface, decrease of the film density, and in some cases adhesion loss at the film/substrate interface, while ion irradiation allows controlling the stress level without generating any macroscopic damage

  8. A multimodal stress monitoring system with canonical correlation analysis.

    Science.gov (United States)

    Unsoo Ha; Changhyeon Kim; Yongsu Lee; Hyunki Kim; Taehwan Roh; Hoi-Jun Yoo

    2015-08-01

    The multimodal stress monitoring headband is proposed for mobile stress management system. It is composed of headband and earplugs. Electroencephalography (EEG), hemoencephalography (HEG) and heart-rate variability (HRV) can be achieved simultaneously in the proposed system for user status estimation. With canonical correlation analysis (CCA) and temporal-kernel CCA (tkCCA) algorithm, those different signals can be combined for maximum correlation. Thanks to the proposed combination algorithm, the accuracy of the proposed system increased up to 19 percentage points than unimodal monitoring system in n-back task.

  9. Development of Generalized Correlation Equation for the Local Wall Shear Stress

    International Nuclear Information System (INIS)

    Jeon, Yu Mi; Park, Ju Hwan

    2010-06-01

    The pressure drop characteristics for a fuel channel are essential for the design and reliable operation of a nuclear reactor. Over several decades, analytical methods have been developed to predict the friction factor in the fuel bundle flows. In order to enhance the accuracy of prediction for the pressure drop in a rod bundle, the influences of a channel wall and the local shear stress distribution should be considered. Therefore, the correlation equation for a local wall shear stress distribution should be developed in order to secure an analytical solution for the friction factor of a rod bundle. For a side subchannel, which has the influence of the channel wall, the local wall shear stress distribution is dependent on the ratio of wall to diameter (W/D) as well as the ratio of pitch to diameter (P/D). In the case that W/D has the same value with P/D, the local shear stress distribution can be simply correlated with the function of angular position for each value of P/D. While in the case where W/D has a different value than P/D, the correlation equation should be developed for each case of P/D and W/D. Therefore, in the present study, the generalized correlation equation of the local wall shear stress distribution was developed for a side subchannel in the case where W/D has a different value than P/D. Consequently, the generalized correlation equation of a local wall shear stress distribution can be represented by the equivalent pitch to diameter ratio, P'/D for the case that P/D and W/D had a different value

  10. Correlates of First-Time Mothers' Postpartum Stress

    Directory of Open Access Journals (Sweden)

    Chich-Hsiu Hung

    2006-10-01

    Full Text Available The purpose of this study was to examine first-time mothers' postpartum stress and its correlates following discharge from the hospital or clinic after vaginal delivery. One hundred and eightythree first-time mothers were enrolled from hospitals and clinics in Kaohsiung City. All first-time mothers reported normal pregnancies and vaginal deliveries, delivered healthy infants at term, and were surveyed during their postpartum periods after discharge from hospitals or clinics. The Hung Postpartum Stress Scale was used to examine first-time mothers' postpartum stress and stressors during their postpartum periods. The top ten postpartum stressors perceived by the women were: “the baby getting sick suddenly”, “the flabby flesh of my belly”, “the unpredictability of the baby's schedule”, “interrupted sleep”, “the shape of the baby's head due to the sleeping position”, “not sleeping enough”, “lack of information regarding infant's growth and development”, “the baby's crying”, “my life is restricted”, and “the baby choking during feeding”. There were no significant differences between the first-time mothers' demographic characteristics and their postpartum stress and its three components (negative body changes, maternal role attainment, lack of social support, respectively. Insight into the study results of first-time mothers' post- partum stress and stressors provides a reference for health professionals that the development of programs and resources addressing primiparous women's unique needs are required.

  11. Stress Redistribution Explains Anti-correlated Subglacial Pressure Variations

    Directory of Open Access Journals (Sweden)

    Pierre-Marie Lefeuvre

    2018-01-01

    Full Text Available We used a finite element model to interpret anti-correlated pressure variations at the base of a glacier to demonstrate the importance of stress redistribution in the basal ice. We first investigated two pairs of load cells installed 20 m apart at the base of the 210 m thick Engabreen glacier in Northern Norway. The load cell data for July 2003 showed that pressurisation of a subglacial channel located over one load cell pair led to anti-correlation in pressure between the two pairs. To investigate the cause of this anti-correlation, we used a full Stokes 3D model of a 210 m thick and 25–200 m wide glacier with a pressurised subglacial channel represented as a pressure boundary condition. The model reproduced the anti-correlated pressure response at the glacier bed and variations in pressure of the same order of magnitude as the load cell observations. The anti-correlation pattern was shown to depend on the bed/surface slope. On a flat bed with laterally constrained cross-section, the resulting bridging effect diverted some of the normal forces acting on the bed to the sides. The anti-correlated pressure variations were then reproduced at a distance >10–20 m from the channel. In contrast, when the bed was inclined, the channel support of the overlying ice was vertical only, causing a reduction of the normal stress on the bed. With a bed slope of 5 degrees, the anti-correlation occurred within 10 m of the channel. The model thus showed that the effect of stress redistribution can lead to an opposite response in pressure at the same distance from the channel and that anti-correlation in pressure is reproduced without invoking cavity expansion caused by sliding.

  12. Casimir stress inside planar materials

    Science.gov (United States)

    Griniasty, Itay; Leonhardt, Ulf

    2017-09-01

    The Casimir force between macroscopic bodies is well understood, but not the Casimir force inside bodies. Guided by a physically intuitive picture, we develop the macroscopic theory of the renormalized Casimir stress inside planar materials (where the electromagnetic properties vary in one direction). Our theory may be applied in predicting how inhomogeneous fluids respond to Casimir forces.

  13. The correlates of stress, coping styles and psychiatric morbidity in ...

    African Journals Online (AJOL)

    The correlates of stress, coping styles and psychiatric morbidity in the first year of medical education at a Nigerian University. ... African Journal of Psychiatry ... used included socio demographic, sources of stress, the general health questionnaire-12 (GHQ-12), Maslachfs burnout inventory (MBI), and Brief COPE. Data were ...

  14. PWSCC Growth Assessment Model Considering Stress Triaxiality Factor for Primary Alloy 600 Components

    Directory of Open Access Journals (Sweden)

    Jong-Sung Kim

    2016-08-01

    Full Text Available We propose a primary water stress corrosion cracking (PWSCC initiation model of Alloy 600 that considers the stress triaxiality factor to apply to finite element analysis. We investigated the correlation between stress triaxiality effects and PWSCC growth behavior in cold-worked Alloy 600 stream generator tubes, and identified an additional stress triaxiality factor that can be added to Garud's PWSCC initiation model. By applying the proposed PWSCC initiation model considering the stress triaxiality factor, PWSCC growth simulations based on the macroscopic phenomenological damage mechanics approach were carried out on the PWSCC growth tests of various cold-worked Alloy 600 steam generator tubes and compact tension specimens. As a result, PWSCC growth behavior results from the finite element prediction are in good agreement with the experimental results.

  15. Stress-stress correlator in ϕ 4 theory: poles or a cut?

    Science.gov (United States)

    Moore, Guy D.

    2018-05-01

    We explore the analytical properties of the traceless stress tensor 2-point function at zero momentum and small frequency (relevant for shear viscosity and hydrodynamic response) in hot, weakly coupled λ ϕ 4 theory. We show that, rather than one or a small number of poles, the correlator has a cut along the negative imaginary frequency axis. We briefly discuss this result's relevance for constructing 2'nd order hydrodynamic models of hot relativistic field theories.

  16. Metastability at the Yield-Stress Transition in Soft Glasses

    Directory of Open Access Journals (Sweden)

    Matteo Lulli

    2018-05-01

    Full Text Available We study the solid-to-liquid transition in a two-dimensional fully periodic soft-glassy model with an imposed spatially heterogeneous stress. The model we consider consists of droplets of a dispersed phase jammed together in a continuous phase. When the peak value of the stress gets close to the yield stress of the material, we find that the whole system intermittently tunnels to a metastable “fluidized” state, which relaxes back to a metastable “solid” state by means of an elastic-wave dissipation. This macroscopic scenario is studied through the microscopic displacement field of the droplets, whose time statistics displays a remarkable bimodality. Metastability is rooted in the existence, in a given stress range, of two distinct stable rheological branches, as well as long-range correlations (e.g., large dynamic heterogeneity developed in the system. Finally, we show that a similar behavior holds for a pressure-driven flow, thus suggesting possible experimental tests.

  17. Metastability at the Yield-Stress Transition in Soft Glasses

    Science.gov (United States)

    Lulli, Matteo; Benzi, Roberto; Sbragaglia, Mauro

    2018-04-01

    We study the solid-to-liquid transition in a two-dimensional fully periodic soft-glassy model with an imposed spatially heterogeneous stress. The model we consider consists of droplets of a dispersed phase jammed together in a continuous phase. When the peak value of the stress gets close to the yield stress of the material, we find that the whole system intermittently tunnels to a metastable "fluidized" state, which relaxes back to a metastable "solid" state by means of an elastic-wave dissipation. This macroscopic scenario is studied through the microscopic displacement field of the droplets, whose time statistics displays a remarkable bimodality. Metastability is rooted in the existence, in a given stress range, of two distinct stable rheological branches, as well as long-range correlations (e.g., large dynamic heterogeneity) developed in the system. Finally, we show that a similar behavior holds for a pressure-driven flow, thus suggesting possible experimental tests.

  18. Development of generalized correlation equation for the local wall shear stress

    International Nuclear Information System (INIS)

    Jeon, Yu Mi; Bae, Jun Ho; Park, Joo Hwan

    2010-01-01

    The pressure drop characteristics for a fuel channel are essential for the design and reliable operation of a nuclear reactor. Over several decades, analytical methods have been developed to predict the friction factor in the fuel bundle flows. In order to enhance the accuracy of prediction for the pressure drop in a rod bundle, the influences of a channel wall and the local shear stress distribution should be considered. Hence, the correlation equation for a local shear stress distribution should be developed in order to secure an analytical solution for the friction factor of a rod bundle. For a side subchannel, which has the influence of the channel wall, the local shear stress distribution is dependent on the ratio of wall to diameter (W/D) as well as the ratio of pitch to diameter (P/D). In the case that W/D has the same value with P/D, the local shear stress distribution can be simply correlated with the function of angular position for each value of P/D. While, in the case that W/D has the different value with P/D, the correlation equation should be developed for each case of P/D and W/D. Hence, in the present study, the generalized correlation equation of a local shear stress distribution is developed for a side subchannel in the case that W/D has the different value with P/D

  19. Correlates of posttraumatic stress disorder in adults with congenital heart disease.

    Science.gov (United States)

    Eslami, Bahareh

    2017-05-01

    The aims of this study were to compare the level of posttraumatic stress disorder between adults with and without congenital heart disease, and to examine the correlates of posttraumatic stress disorder (e.g., sociodemographics). Cross-sectional. Two university-affiliated heart hospitals in Tehran, Iran. A sample of 347 adults with congenital heart disease aged 18-64 years (52% women), and 353 adults without congenital heart disease matched by sex and age (±2 years) was recruited. The PTSD Scale: Self-report version was used to assess the diagnosis and severity of posttraumatic stress disorder. Hierarchical multivariate logistic regression analyses were performed to explore correlates of likely posttraumatic stress disorder diagnosis among each group of participants. The posttraumatic stress disorder in the patients was comparable to those of the control group, except for increased arousal (P = .027) which was scored higher among the patients. Over 52% of adults with congenital heart disease met the criteria for a likely posttraumatic stress disorder diagnosis compared with 48% of adults without congenital heart disease. The regression analyses among patients revealed that elevated depressive symptoms (OR = 1.27) and a positive history of cardiac surgery (OR = 2.02) were significantly associated with posttraumatic stress disorder. The model could explain 29% of the variance in posttraumatic stress disorder. The high and comparable prevalence of posttraumatic stress disorder among patients and nonpatients highlight the significance of the context in which adults with congenital heart disease may face other/additional stressors than disease-related ones, an issue that clinicians need also take into account. Furthermore, the association of posttraumatic stress disorder with elevated depressive symptoms warrant a comprehensive psychological assessment and management of adults with congenital heart disease, in particular among those with a history of

  20. Nutritional Correlates of Perceived Stress among University Students in Egypt

    Directory of Open Access Journals (Sweden)

    Walid El Ansari

    2015-11-01

    Full Text Available Food intake choice and amount might change with stress. However, this has not been examined among Egyptian students. We examined students’ stress levels, its correlation with their consumption of a range of food groups, and adherence to dietary guidelines. A cross sectional survey (N = 2810 undergraduates at 11 faculties at Assiut University, Egypt assessed two composite food intake pattern scores (one unhealthy: sweets, cakes, snacks; and a healthy one: fruits and vegetables, and two indicators of healthy eating (subjective importance of healthy eating; and dietary guideline adherence index. Multiple linear regression tested the associations of stress with two food intake pattern scores and two indicators of healthy eating, controlling for six potential confounders for the sample and separately for males and females. Higher perceived stress score was significantly associated with less frequent food intake of fruit and vegetables in males and females. The association was more pronounced among males than in females. No significant association was observed between the sweets cakes and snacks score and stress. Of the two indicators of healthy eating, the dietary guideline adherence index was not associated with stress, while the subjective judgment of healthy eating was consistently negatively associated with stress. Stress related decreased-eating was present. Recent studies suggest that stress could be associated with either decreased or increased eating depending on the study population, food group, and type of stressor. Further research is necessary to understand stress related over- and undereating.

  1. Nutritional Correlates of Perceived Stress among University Students in Egypt.

    Science.gov (United States)

    El Ansari, Walid; Berg-Beckhoff, Gabriele

    2015-11-06

    Food intake choice and amount might change with stress. However, this has not been examined among Egyptian students. We examined students' stress levels, its correlation with their consumption of a range of food groups, and adherence to dietary guidelines. A cross sectional survey (N = 2810 undergraduates at 11 faculties at Assiut University, Egypt) assessed two composite food intake pattern scores (one unhealthy: sweets, cakes, snacks; and a healthy one: fruits and vegetables), and two indicators of healthy eating (subjective importance of healthy eating; and dietary guideline adherence index). Multiple linear regression tested the associations of stress with two food intake pattern scores and two indicators of healthy eating, controlling for six potential confounders for the sample and separately for males and females. Higher perceived stress score was significantly associated with less frequent food intake of fruit and vegetables in males and females. The association was more pronounced among males than in females. No significant association was observed between the sweets cakes and snacks score and stress. Of the two indicators of healthy eating, the dietary guideline adherence index was not associated with stress, while the subjective judgment of healthy eating was consistently negatively associated with stress. Stress related decreased-eating was present. Recent studies suggest that stress could be associated with either decreased or increased eating depending on the study population, food group, and type of stressor. Further research is necessary to understand stress related over- and undereating.

  2. ER stress-induced protein, VIGG, disturbs plant cation homeostasis, which is correlated with growth retardation and robustness to ER stress

    International Nuclear Information System (INIS)

    Katoh, Hironori; Fujita, Keiko; Takuhara, Yuki; Ogawa, Atsushi; Suzuki, Shunji

    2011-01-01

    Highlights: → VIGG is an ER stress-induced protein in plant. → We examine the characteristics of VIGG-overexpressing Arabidopsis plants. → VIGG-overexpressing plants reveal growth retardation and robustness to ER stress. → VIGG disturbs cation homeostasis in plant. -- Abstract: VIGG is a putative endoplasmic reticulum (ER) resident protein induced by virus infection and ER stress, and is correlated with fruit quality in grapevine. The present study was undertaken to determine the biological function of VIGG in grapevine. Experiments using fluorescent protein-VIGG fusion protein demonstrated that VIGG is localized in ER and the ER targeting sequence is in the N-terminus. The overexpression of VIGG in Arabidopsis plant led to growth retardation. The rosette leaves of VIGG-overexpressing plants were smaller than those of the control plants and rolled at 42 days after seeding. VIGG-overexpressing plants revealed robustness to ER stress as well as the low expression of ER stress marker proteins, such as the luminal binding proteins. These characteristics of VIGG-overexpressing plants were supported by a microarray experiment that demonstrated the disruption of genes related to ER stress response and flowering, as well as cation mobility, in the plants. Finally, cation homeostasis in the plants was disturbed by the overexpression of VIGG. Taken together, these results suggest that VIGG may disturb cation homeostasis in plant, which is correlated with the robustness to ER stress and growth retardation.

  3. ER stress-induced protein, VIGG, disturbs plant cation homeostasis, which is correlated with growth retardation and robustness to ER stress

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Hironori; Fujita, Keiko; Takuhara, Yuki [Laboratory of Fruit Genetic Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi 400-0005 (Japan); Ogawa, Atsushi [Department of Biological Production, Akita Prefectural University, Shimosinjyou-nakano 241-438, Akita 010-0195 (Japan); Suzuki, Shunji, E-mail: suzukis@yamanashi.ac.jp [Laboratory of Fruit Genetic Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi 400-0005 (Japan)

    2011-02-18

    Highlights: {yields} VIGG is an ER stress-induced protein in plant. {yields} We examine the characteristics of VIGG-overexpressing Arabidopsis plants. {yields} VIGG-overexpressing plants reveal growth retardation and robustness to ER stress. {yields} VIGG disturbs cation homeostasis in plant. -- Abstract: VIGG is a putative endoplasmic reticulum (ER) resident protein induced by virus infection and ER stress, and is correlated with fruit quality in grapevine. The present study was undertaken to determine the biological function of VIGG in grapevine. Experiments using fluorescent protein-VIGG fusion protein demonstrated that VIGG is localized in ER and the ER targeting sequence is in the N-terminus. The overexpression of VIGG in Arabidopsis plant led to growth retardation. The rosette leaves of VIGG-overexpressing plants were smaller than those of the control plants and rolled at 42 days after seeding. VIGG-overexpressing plants revealed robustness to ER stress as well as the low expression of ER stress marker proteins, such as the luminal binding proteins. These characteristics of VIGG-overexpressing plants were supported by a microarray experiment that demonstrated the disruption of genes related to ER stress response and flowering, as well as cation mobility, in the plants. Finally, cation homeostasis in the plants was disturbed by the overexpression of VIGG. Taken together, these results suggest that VIGG may disturb cation homeostasis in plant, which is correlated with the robustness to ER stress and growth retardation.

  4. Correlation of occupational stress with depression, anxiety, and sleep in Korean dentists: cross-sectional study.

    Science.gov (United States)

    Song, Kyung-Won; Choi, Won-Seok; Jee, Hee-Jung; Yuh, Chi-Sung; Kim, Yong-Ku; Kim, Leen; Lee, Heon-Jeong; Cho, Chul-Hyun

    2017-12-12

    This study aimed to investigate the degree of occupational stress and the clinical mental state of dentists. In addition, we investigated the correlation of occupational stress with depression, anxiety, and sleep among dentists in Korea. A cross-sectional survey on 231 dentists was conducted using the Doctor Job Stress Scale, Center for Epidemiologic Studies Depression Scale (CES-D), State-Trait Anxiety Index (STAI), and Pittsburgh Sleep Quality Index (PSQI). Correlation of occupational stress with mental health was investigated by adjusted multiple regression analysis. The scores of CES-D, STAI, and PSQI revealed a significant correlation with the Doctor Job Stress Scale (t = 3.93, P stress management focusing on interpersonal relationship with patients and responsibility as an expert rather than the intensity of work should be considered.

  5. Effect of silane dilution on intrinsic stress in glow discharge hydrogenated amorphous silicon films

    Science.gov (United States)

    Harbison, J. P.; Williams, A. J.; Lang, D. V.

    1984-02-01

    Measurements of the intrinsic stress in hydrogenated amorphous silicon (a-Si : H) films grown by rf glow discharge decomposition of silane diluted to varying degrees in argon are presented. Films are found to grow under exceedingly high compressive stress. Low values of macroscopic film density and low stress values are found to correlate with high growth rate. An abrupt drop in stress occurs between 2 and 3% silane at precisely the point where columnar growth morphology appears. No corresponding abrupt change is noted in density, growth rate, or plasma species concentrations as determined by optical emissioin spectroscopy. Finally a model of diffusive incorporation of hydrogen or some gaseous impurity during growth into the bulk of the film behind the growing interface is proposed to explain the results.

  6. Resting cardiointegram: correlation with stress thallium perfusion studies

    International Nuclear Information System (INIS)

    Gould, L.A.; Betzu, R.; Judge, D.; Lee, J.; Taddeo, M.; Yang, D.

    1988-01-01

    The cardiointegram is a noninvasive technique for the analysis of the electrical signals of the heart obtained by a transformation of the voltage versus time format by a series of integrations. The stress thallium perfusion study is a widely used test for the detection of coronary artery disease. In order to evaluate the correlation between the resting cardiointegram and the stress thallium 201 perfusion study, 20 patients with normal resting electrocardiograms underwent stress thallium tests and resting cardiointegrams. The cardiointegram was determined on two resting complexes of leads I, II, V4, V5, and V6 and called abnormal if five of ten complexes deviated outside a normalized template. There was concordance of the cardiointegram and the thallium study in 16 of 20 patients (80%). The sensitivity for the detection of coronary artery disease was 71%, and the specificity was 80%. The overall accuracy was 74%. Thus in patients with normal electrocardiograms, the cardiointegram is a useful noninvasive test for the detection of coronary artery disease

  7. Correlates of depression, anxiety and stress among Malaysian university students.

    Science.gov (United States)

    Shamsuddin, Khadijah; Fadzil, Fariza; Ismail, Wan Salwina Wan; Shah, Shamsul Azhar; Omar, Khairani; Muhammad, Noor Azimah; Jaffar, Aida; Ismail, Aniza; Mahadevan, Raynuha

    2013-08-01

    University students face not only challenges related with independent living, but also academic challenges. This predisposes them to depression, anxiety and stress, which are fairly common. The aim was to assess the prevalence of depression, anxiety and stress, and identify their correlates among university students. A cross-sectional study was conducted on 506 students between the ages of 18 and 24 years from four public universities in the Klang Valley, Malaysia. Through an anonymous, self administered questionnaire, they were assessed by the Depression Anxiety Stress Scale-21 (DASS-21). Data on socio-demographic, family characteristics and living arrangement were also obtained. Student's t-test and one-way ANOVA were used to explore association between these aspects. Analysis showed among all students, 27.5% had moderate, and 9.7% had severe or extremely severe depression; 34% had moderate, and 29% had severe or extremely severe anxiety; and 18.6% had moderate and 5.1% had severe or extremely severe stress scores based on the DASS-21 inventory. Both depression and anxiety scores were significantly higher among older students (20 and above) and those born in rural areas. Whereas, higher stress scores were significantly higher among older students (20 and above), females, Malays and those whose family had either low or high incomes compared to those with middle incomes. The prevalence of anxiety is much higher than either depression or stress, with some differences in their correlates except for age. These differences need to be further explored for development of better intervention programs and appropriate support services targeting this group. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Electromagnetic stress at the boundary: Photon pressure or tension?

    Science.gov (United States)

    Wang, Shubo; Ng, Jack; Xiao, Meng; Chan, Che Ting

    2016-03-01

    It is well known that incident photons carrying momentum ℏk exert a positive photon pressure. But if light is impinging from a negative refractive medium in which ℏk is directed toward the source of radiation, should light exert a photon "tension" instead of a photon pressure? Using an ab initio method that takes the underlying microstructure of a material into account, we find that when an electromagnetic wave propagates from one material into another, the electromagnetic stress at the boundary is, in fact, indeterminate if only the macroscopic parameters are specified. Light can either pull or push the boundary, depending not only on the macroscopic parameters but also on the microscopic lattice structure of the polarizable units that constitute the medium. Within the context of an effective-medium approach, the lattice effect is attributed to electrostriction and magnetostriction, which can be accounted for by the Helmholtz stress tensor if we use the macroscopic fields to calculate the boundary optical stress.

  9. Raman study of lead zirconate titanate under uniaxial stress

    International Nuclear Information System (INIS)

    Tallant, David R.; Simpson, Regina L.; Grazier, J. Mark; Zeuch, David H.; Olson, Walter R.; Tuttle, Bruce A.

    2000-01-01

    The authors used micro-Raman spectroscopy to monitor the ferroelectric (FE) to antiferroelectric (AFE) phase transition in PZT ceramic bars during the application of uniaxial stress. They designed and constructed a simple loading device, which can apply sufficient uniaxial force to transform reasonably large ceramic bars while being small enough to fit on the mechanical stage of the microscope used for Raman analysis. Raman spectra of individual grains in ceramic PZT bars were obtained as the stress on the bar was increased in increments. At the same time gauges attached to the PZT bar recorded axial and lateral strains induced by the applied stress. The Raman spectra were used to calculate an FE coordinate, which is related to the fraction of FE phase present. The authors present data showing changes in the FE coordinates of individual PZT grains and correlate these changes to stress-strain data, which plot the macroscopic evolution of the FE-to-AFE transformation. Their data indicates that the FE-to-AFE transformation does not occur simultaneously for all PZT grains but that grains react individually to local conditions

  10. Nutritional Correlates of Perceived Stress among University Students in Egypt

    OpenAIRE

    Ansari, Walid El; Berg-Beckhoff, Gabriele

    2015-01-01

    Food intake choice and amount might change with stress. However, this has not been examined among Egyptian students. We examined students' stress levels, its correlation with their consumption of a range of food groups, and adherence to dietary guidelines. A cross sectional survey (N = 2810 undergraduates at 11 faculties at Assiut University, Egypt) assessed two composite food intake pattern scores (one unhealthy: sweets, cakes, snacks; and a healthy one: fruits and vegetables), and two indic...

  11. Prediction of life stress on athletes' burnout: the dual role of perceived stress.

    Science.gov (United States)

    Chyi, Theresa; Lu, Frank Jing-Horng; Wang, Erica T W; Hsu, Ya-Wen; Chang, Ko-Hsin

    2018-01-01

    Although many studies adopted Smith's (1986) cognitive-affective model of athletic burnout in examining stress-burnout relationship, very few studies examined the mediating/moderating role of perceived stress on the stress-burnout relationship. We sampled 195 college student-athletes and assessed their life stress, perceived stress, and burnout. Correlation analyses found all study variables correlated. Two separate hierarchical regression analyses found that the "distress" component of perceived stress mediated athletes' two types of life stress-burnout relationship but "counter-stress" component of perceived stress-moderated athletes' general-life stress-burnout relationship. We concluded that interweaving relationships among athletes' life stress, perceived stress, and burnout are not straightforward. Future research should consider the nature of athletes life stress, and dual role of perceived stress in examining its' association with related psychological responses in athletic settings.

  12. Residual stress measurement of PMMA by combining drilling-hole with digital speckle correlation method

    Science.gov (United States)

    Yao, X. F.; Xiong, T. C.; Xu, H. M.; Wan, J. P.; Long, G. R.

    2008-11-01

    The residual stresses of the PMMA (polymethyl methacrylate) specimens after being drilled, reamed and polished respectively are investigated using the digital speckle correlation experimental method,. According to the displacement fields around the correlated calculated region, the polynomial curve fitting method is used to obtain the continuous displacement fields, and the strain fields can be obtained from the derivative of the displacement fields. Considering the constitutive equation of the material, the expression of the residual stress can be presented. During the data processing, according to the fitting effect of the data, the calculation region of the correlated speckles and the degree of the polynomial fitting curve is decided. These results show that the maximum stress is at the hole-wall of the drilling hole specimen and with the increasing of the diameter of the drilled hole, the residual stress resulting from the hole drilling increases, whereas the process of reaming and polishing hole can reduce the residual stress. The relative large discrete degree of the residual stress is due to the chip removal ability of the drill bit, the cutting feed of the drill and other various reasons.

  13. Correlation between Kind of Delivery and Posttraumatic Stress ...

    African Journals Online (AJOL)

    Background: Posttraumatic stress disorder (PTSD) is a very common mental condition and a unique anxiety disorder. Aim: The present study tried to examine the correlation between kind of delivery and PTSD. Subjects and Methods: This prospective study evaluated 240 Iranian female residents of Tehran, Iran, during the ...

  14. Flow stress asymmetry and cyclic stress--strain response in a BCC Ti--V alloy

    International Nuclear Information System (INIS)

    Koss, D.A.; Wojcik, C.C.

    1976-01-01

    The cyclic stress-strain response of relatively stable bcc β-phase Ti--40 percent V alloy single crystals was studied. Flow stress asymmetry found in the alloy is attributed to the fact that screw dislocations, when gliding on a (211) plane, are more mobile in the twinning direction than in the antitwinning direction. Thus the flow stress of the crystal is greater when it is sheared in the antitwinning direction than in the twinning direction (the latter case results when crystals of the 100 orientation are stressed in tension and those of the 110 orientation are stressed in compression). Such behavior can be a result of the core of a screw dislocation being asymmetric under stress which causes the flow stress asymmetry observed. It should be noted that screw dislocations dominate the low temperature deformation structure of Ti-40V, which strongly suggests deformation is controlled by screw dislocation motion. The observation in Mo that the microyield stress is independent of crystal orientation could be a result of edge dislocation motion controlling microyield in that instance and this observation would not be inconsistent with screw dislocation motion controlling the macroscopic (epsilon/sub p/ greater than 0.05 percent) deformation measured here

  15. The Correlation of Organizational Role Stressors with Stress Level of Icu Nurses

    OpenAIRE

    Nursalam, Nursalam; Efendi, Ferry; Puspawati, Ni Luh Putu Dewi

    2009-01-01

    Introduction : Work stress which is often experienced by ICU nurses may affects nurse’s performance, nurse’s health and wealth so that the factors which may affect work stress such as organizational role stressors must be noticed. This study was aimed to explain the correlation between organizational role stressors and work stress level in ICU Nurses. Method : This study used cross-sectional design  involved 13 respondents, taken by purposive sampling. The independent variable was organizatio...

  16. The Correlation of Organizational Role Stressors with Stress Level of ICU Nurses

    OpenAIRE

    Nursalam, Nursalam; Efendi, Ferry; Puspawati, Ni Luh Putu Dewi

    2017-01-01

    Introduction : Work stress which is often experienced by ICU nurses may affects nurse’s performance, nurse’s health and wealth so that the factors which may affect work stress such as organizational role stressors must be noticed. This study was aimed to explain the correlation between organizational role stressors and work stress level in ICU Nurses. Method : This study used cross-sectional design  involved 13 respondents, taken by purposive sampling. The independent variable was organizatio...

  17. Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ganapati, Vidya; Schoenfelder, Stephan; Castellanos, Sergio; Oener, Sebastian; Koepge, Ringo; Sampson, Aaron; Marcus, Matthew A.; Lai, Barry; Morhenn, Humphrey; Hahn, Giso; Bagdahn, Joerg; Buonassisi1, Tonio

    2010-05-05

    This manuscript concerns the application of infrared birefringence imaging (IBI) to quantify macroscopic and microscopic internal stresses in multicrystalline silicon (mc-Si) solar cell materials. We review progress to date, and advance four closely related topics. (1) We present a method to decouple macroscopic thermally-induced residual stresses and microscopic bulk defect related stresses. In contrast to previous reports, thermally-induced residual stresses in wafer-sized samples are generally found to be less than 5 MPa, while defect-related stresses can be several times larger. (2) We describe the unique IR birefringence signatures, including stress magnitudes and directions, of common microdefects in mc-Si solar cell materials including: {beta}-SiC and {beta}-Si{sub 3}N{sub 4} microdefects, twin bands, nontwin grain boundaries, and dislocation bands. In certain defects, local stresses up to 40 MPa can be present. (3) We relate observed stresses to other topics of interest in solar cell manufacturing, including transition metal precipitation, wafer mechanical strength, and minority carrier lifetime. (4) We discuss the potential of IBI as a quality-control technique in industrial solar cell manufacturing.

  18. Neural Correlates of Stress- and Food Cue–Induced Food Craving in Obesity

    Science.gov (United States)

    Jastreboff, Ania M.; Sinha, Rajita; Lacadie, Cheryl; Small, Dana M.; Sherwin, Robert S.; Potenza, Marc N.

    2013-01-01

    OBJECTIVE Obesity is associated with alterations in corticolimbic-striatal brain regions involved in food motivation and reward. Stress and the presence of food cues may each motivate eating and engage corticolimibic-striatal neurocircuitry. It is unknown how these factors interact to influence brain responses and whether these interactions are influenced by obesity, insulin levels, and insulin sensitivity. We hypothesized that obese individuals would show greater responses in corticolimbic-striatal neurocircuitry after exposure to stress and food cues and that brain activations would correlate with subjective food craving, insulin levels, and HOMA-IR. RESEARCH DESIGN AND METHODS Fasting insulin levels were assessed in obese and lean subjects who were exposed to individualized stress and favorite-food cues during functional MRI. RESULTS Obese, but not lean, individuals exhibited increased activation in striatal, insular, and hypothalamic regions during exposure to favorite-food and stress cues. In obese but not lean individuals, food craving, insulin, and HOMA-IR levels correlated positively with neural activity in corticolimbic-striatal brain regions during favorite-food and stress cues. The relationship between insulin resistance and food craving in obese individuals was mediated by activity in motivation-reward regions including the striatum, insula, and thalamus. CONCLUSIONS These findings demonstrate that obese, but not lean, individuals exhibit increased corticolimbic-striatal activation in response to favorite-food and stress cues and that these brain responses mediate the relationship between HOMA-IR and food craving. Improving insulin sensitivity and in turn reducing corticolimbic-striatal reactivity to food cues and stress may diminish food craving and affect eating behavior in obesity. PMID:23069840

  19. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang; Liu, Taixiang; Liao, G J; Lubineau, Gilles

    2017-01-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  20. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang

    2017-09-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  1. Relationship between general intelligence, emotional intelligence, stress levels and stress reactivity.

    Science.gov (United States)

    Singh, Yogesh; Sharma, Ratna

    2012-07-01

    Stressful life events and daily life stresses have both deleterious and cumulative effects on human body. In several studies, stress has been shown to affect various parameter of higher mental function like attention, concentration, learning and memory. Present study was designed to explore the relationship among GI level, EI level, psychological stress levels and acute stress reactivity in young normal healthy subjects. The study was conducted on thirty four healthy male student volunteers to study a) acute stress reactivity in subjects with varying levels of General Intelligence (GI) and Emotional Intelligence (EI) and b) correlation between GI, EI, acute stress and perceived stress. Baseline GI and EI and acute stress and perceived stress scores were measured by standard assessment scales. Using median value of GI and EI scores as cutoff values, subjects were categorized into four groups. Among different GI-EI groups, acute stress reactivity was similar but salivary Cortisol (especially post stressor level) and perceived stress level was a differentiating factor. High level of EI was associated inversely with acute and chronic perceived stress level. Significant correlation was found between acute and chronic perceived stress levels. Level of general intelligence showed no relation to acute or chronic stress levels as well as acute stress reactivity. The differences in various groups of GI and EI had no effect on the baseline and post stress performance on Sternberg memory test and all the three conditions of Stroop test. In conclusion emotional intelligence as an attribute is better suited to handle day to day acute stress and chronic perceived stress.

  2. On the quantum mechanical theory of stress and force

    International Nuclear Information System (INIS)

    Nielsen, O.H.; Martin, R.M.

    1985-01-01

    The stress theorem presented previously by the present authors is derived in detail and is related to the virial and force theorems. Stress fields are considered in two alternative forms, which both give the same macroscopic stress and forces on nuclei when integrated over appropriate surfaces. A crucial concept is interactions that ''cross'' surfaces. Explicit forms of the stress field within the local-density approximation are given, together with a generalization of the approximate Liberman form for pressure. Reciprocal-space expressions and ab-initio calculations are considered in detail in an accompanying paper. (orig.)

  3. Modeling of grain boundary stresses in Alloy 600

    Energy Technology Data Exchange (ETDEWEB)

    Kozaczek, K.J. [Oak Ridge National Lab., TN (United States); Sinharoy, A.; Ruud, C.O. [Pennsylvania State Univ., University Park, PA (United States); Mcllree, A.R. [Electric Power Research Inst., Palo Alto, CA (United States)

    1995-04-01

    Corrosive environments combined with high stress levels and susceptible microstructures can cause intergranular stress corrosion cracking (IGSCC) of Alloy 600 components on both primary and secondary sides of pressurized water reactors. One factor affecting the IGSCC is intergranular carbide precipitation controlled by heat treatment of Alloy 600. This study is concerned with analysis of elastic stress fields in vicinity of M{sub 7}C{sub 3} and M{sub 23}C{sub 6} carbides precipitated in the matrix and at a grain boundary triple point. The local stress concentration which can lead to IGSCC initiation was studied using a two-dimensional finite element model. The intergranular precipitates are more effective stress raisers than the intragranular precipitates. The combination of the elastic property mismatch and the precipitate shape can result in a local stress field substantially different than the macroscopic stress. The maximum local stresses in the vicinity of the intergranular precipitate were almost twice as high as the applied stress.

  4. Restoring method for missing data of spatial structural stress monitoring based on correlation

    Science.gov (United States)

    Zhang, Zeyu; Luo, Yaozhi

    2017-07-01

    Long-term monitoring of spatial structures is of great importance for the full understanding of their performance and safety. The missing part of the monitoring data link will affect the data analysis and safety assessment of the structure. Based on the long-term monitoring data of the steel structure of the Hangzhou Olympic Center Stadium, the correlation between the stress change of the measuring points is studied, and an interpolation method of the missing stress data is proposed. Stress data of correlated measuring points are selected in the 3 months of the season when missing data is required for fitting correlation. Data of daytime and nighttime are fitted separately for interpolation. For a simple linear regression when single point's correlation coefficient is 0.9 or more, the average error of interpolation is about 5%. For multiple linear regression, the interpolation accuracy is not significantly increased after the number of correlated points is more than 6. Stress baseline value of construction step should be calculated before interpolating missing data in the construction stage, and the average error is within 10%. The interpolation error of continuous missing data is slightly larger than that of the discrete missing data. The data missing rate of this method should better not exceed 30%. Finally, a measuring point's missing monitoring data is restored to verify the validity of the method.

  5. Correlation between electron-irradiation defects and applied stress in graphene: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Kida, Shogo; Yamamoto, Masaya; Kawata, Hiroaki; Hirai, Yoshihiko; Yasuda, Masaaki, E-mail: yasuda@pe.osakafu-u.ac.jp [Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Tada, Kazuhiro [Department of Electrical and Control Systems Engineering, National Institute of Technology, Toyama College, Toyama 939-8630 (Japan)

    2015-09-15

    Molecular dynamics (MD) simulations are performed to study the correlation between electron irradiation defects and applied stress in graphene. The electron irradiation effect is introduced by the binary collision model in the MD simulation. By applying a tensile stress to graphene, the number of adatom-vacancy (AV) and Stone–Wales (SW) defects increase under electron irradiation, while the number of single-vacancy defects is not noticeably affected by the applied stress. Both the activation and formation energies of an AV defect and the activation energy of an SW defect decrease when a tensile stress is applied to graphene. Applying tensile stress also relaxes the compression stress associated with SW defect formation. These effects induced by the applied stress cause the increase in AV and SW defect formation under electron irradiation.

  6. Examining the dimensions and correlates of workplace stress among Australian veterinarians.

    Science.gov (United States)

    Smith, Derek R; Leggat, Peter A; Speare, Richard; Townley-Jones, Maureen

    2009-12-08

    Although stress is known to be a common occupational health issue in the veterinary profession, few studies have investigated its broad domains or the internal validity of the survey instrument used for assessment. We analysed data from over 500 veterinarians in Queensland, Australia, who were surveyed during 2006-07. The most common causes of stress were reported to be long hours worked per day, not having enough holidays per year, not having enough rest breaks per day, the attitude of customers, lack of recognition from the public and not having enough time per patient. Age, gender and practice type were statistically associated with various aspects of work-related stress. Strong correlations were found between having too many patients per day and not having enough time per patient; between not having enough holidays and long working hours; and also between not enough rest breaks per day and long working hours. Factor analysis revealed four dimensions of stress comprising a mixture of career, professional and practice-related items. The internal validity of our stress questionnaire was shown to be high during statistical analysis. Overall, this study suggests that workplace stress is fairly common among Australian veterinarians and represents an issue that occupies several distinct areas within their professional life.

  7. Examining the dimensions and correlates of workplace stress among Australian veterinarians

    Directory of Open Access Journals (Sweden)

    Leggat Peter A

    2009-12-01

    Full Text Available Abstract Background Although stress is known to be a common occupational health issue in the veterinary profession, few studies have investigated its broad domains or the internal validity of the survey instrument used for assessment. Methods We analysed data from over 500 veterinarians in Queensland, Australia, who were surveyed during 2006-07. Results The most common causes of stress were reported to be long hours worked per day, not having enough holidays per year, not having enough rest breaks per day, the attitude of customers, lack of recognition from the public and not having enough time per patient. Age, gender and practice type were statistically associated with various aspects of work-related stress. Strong correlations were found between having too many patients per day and not having enough time per patient; between not having enough holidays and long working hours; and also between not enough rest breaks per day and long working hours. Factor analysis revealed four dimensions of stress comprising a mixture of career, professional and practice-related items. The internal validity of our stress questionnaire was shown to be high during statistical analysis. Conclusion Overall, this study suggests that workplace stress is fairly common among Australian veterinarians and represents an issue that occupies several distinct areas within their professional life.

  8. Casimir stress in an inhomogeneous medium

    International Nuclear Information System (INIS)

    Philbin, T.G.; Xiong, C.; Leonhardt, U.

    2010-01-01

    The Casimir effect in an inhomogeneous dielectric is investigated using Lifshitz's theory of electromagnetic vacuum energy. A permittivity function that depends continuously on one Cartesian coordinate is chosen, bounded on each side by homogeneous dielectrics. The result for the Casimir stress is infinite everywhere inside the inhomogeneous region, a divergence that does not occur for piece-wise homogeneous dielectrics with planar boundaries. A Casimir force per unit volume can be extracted from the infinite stress but it diverges on the boundaries between the inhomogeneous medium and the homogeneous dielectrics. An alternative regularization of the vacuum stress is considered that removes the contribution of the inhomogeneity over small distances, where macroscopic electromagnetism is invalid. The alternative regularization yields a finite Casimir stress inside the inhomogeneous region, but the stress and force per unit volume diverge on the boundaries with the homogeneous dielectrics. The case of inhomogeneous dielectrics with planar boundaries thus falls outside the current understanding of the Casimir effect.

  9. Prediction of life stress on athletes’ burnout: the dual role of perceived stress

    Science.gov (United States)

    Wang, Erica T.W.; Hsu, Ya-Wen; Chang, Ko-Hsin

    2018-01-01

    Although many studies adopted Smith’s (1986) cognitive–affective model of athletic burnout in examining stress–burnout relationship, very few studies examined the mediating/moderating role of perceived stress on the stress–burnout relationship. We sampled 195 college student-athletes and assessed their life stress, perceived stress, and burnout. Correlation analyses found all study variables correlated. Two separate hierarchical regression analyses found that the “distress” component of perceived stress mediated athletes’ two types of life stress–burnout relationship but “counter-stress” component of perceived stress-moderated athletes’ general-life stress–burnout relationship. We concluded that interweaving relationships among athletes’ life stress, perceived stress, and burnout are not straightforward. Future research should consider the nature of athletes life stress, and dual role of perceived stress in examining its’ association with related psychological responses in athletic settings. PMID:29362691

  10. Prediction of life stress on athletes’ burnout: the dual role of perceived stress

    Directory of Open Access Journals (Sweden)

    Theresa Chyi

    2018-01-01

    Full Text Available Although many studies adopted Smith’s (1986 cognitive–affective model of athletic burnout in examining stress–burnout relationship, very few studies examined the mediating/moderating role of perceived stress on the stress–burnout relationship. We sampled 195 college student-athletes and assessed their life stress, perceived stress, and burnout. Correlation analyses found all study variables correlated. Two separate hierarchical regression analyses found that the “distress” component of perceived stress mediated athletes’ two types of life stress–burnout relationship but “counter-stress” component of perceived stress-moderated athletes’ general-life stress–burnout relationship. We concluded that interweaving relationships among athletes’ life stress, perceived stress, and burnout are not straightforward. Future research should consider the nature of athletes life stress, and dual role of perceived stress in examining its’ association with related psychological responses in athletic settings.

  11. Correlates of parental stress and psychopathology in pediatric epilepsy

    Directory of Open Access Journals (Sweden)

    Rania Shatla

    2011-01-01

    Full Text Available Background: Chronic conditions like epilepsy in a child can affect his/her entire family. The failure of the family members to adapt adequately to the unique demands of this childhood chronic illness can be considered as an important risk factor for development of psychopathology. Objectives: The objectives of this study were to study the profile of parenting stress in parents of children with epilepsy and its correlates; and, to examine the correlates of psychopathology in these children. Material and Methods: Twenty three epileptic children and their families were subjected to Parenting Stress Index (PSI, Scores for indices such as The Children′s Depression Inventory (CDI, Benton Visual Retention test, Spence anxiety scale for children, The Child Behavior Checklist (CBCL and Wechsler Intelligence Scale for Children were calculated. Results: Mean verbal and performance IQ score was 94, while the mean total IQ score was 95. Mean scores for all Wechsler IQ Scores as well as Benton Visual retention test were within the average range. Means for total internalizing CBCL t scores (M, Mean=70; Standard Deviation, SD=4.4, total externalizing CBCL t scores (M=60, SD=9.6, and total behavior problems CBCL t scores (M=67, SD=5.2 were above the standard cut off levels of 65 for clinical behavioral problems. Mean score on CDI was 42 ± 2. Scores of the PSI equal to or higher than 85 th percentile were considered pathologically high. Conclusion: The results of our study indicated that pediatric patients with epilepsy, specifically with intractable cases, are correlated with high levels of parental stress.

  12. Stress symptoms among adolescents before and after scoliosis surgery: correlations with postoperative pain.

    Science.gov (United States)

    Rullander, Anna-Clara; Lundström, Mats; Lindkvist, Marie; Hägglöf, Bruno; Lindh, Viveca

    2016-04-01

    The aim of this study was to describe stress symptoms among adolescents before and after scoliosis surgery and to explore correlations with postoperative pain. Scoliosis surgery is a major surgical procedure. Adolescent patients suffer from preoperative stress and severe postoperative pain. Previous studies indicate that there is a risk of traumatisation and psychological complications during the recovery period. A prospective quantitative cohort study with consecutive inclusion of participants. A cohort of 37 adolescent patients aged 13-18. To assess the adolescents' experiences before surgery and at six to eight months after surgery, the Trauma Symptom Checklist for Children - Alternative version, Youth Self-Report and Kiddie Schedule for Affective Disorder and Schizophrenia for children 12-18 were used. The Visual Analogue Scale was used for self-report of postoperative pain on day three. Rates of anxiety/depression and internalising behaviour were significantly higher before surgery than six months after. Preoperative anger, social problems and attention problems correlated significantly with postoperative pain on day three. At follow-up, postoperative pain correlated significantly with anxiety, social problems and attention problems. The results of this study indicate a need for interventions to reduce perioperative stress and postoperative pain to improve the quality of nursing care. Attention to preoperative stress and implementation of interventions to decrease stress symptoms could ameliorate the perioperative process by reducing levels of postoperative pain, anxiety, social and attention problems in the recovery period. © 2016 John Wiley & Sons Ltd.

  13. [Sub-health status of middle school teachers and its correlation analysis with occupational stress].

    Science.gov (United States)

    Chang, W J; Shao, H M; Zhi, X Y; Xu, J; Xie, J

    2017-08-20

    Objective: To study the distribution of sub-health and occupational stress as well as their correlation among middle school teachers in Tianjin, then provide evidences for prevention and control of the status of sub-health. Methods: A total of 3 522 middle school teachers from six districts of Tianjin were recruited with stratified cluster sampling strategy for the investigation of Sub-Health Measurement Scale version 1.0 (SHMS V1.0) and Occupational Stress Inventory-Revised Edition (OSI-R) . Results: Detection rate of sub-health status among Tianjin middle school teachers was 58.55%. Men had significantly lower sub-health detection rate (55.19%) than women (59.71%) . Sub-health detection rate increased with age ( P occupational stress norm of China ( P occupational stress of middle school teachers showed that the scores of occupational role and personal strain were negatively correlated with the scores of sub-health state ( P occupational stress level of middle school teachers, increase personal resources, and scientific and effective health guidance and education should be strengthened.

  14. Sex-dependent effects of stress on brain correlates to empathy for pain.

    Science.gov (United States)

    Gonzalez-Liencres, Cristina; Breidenstein, Anja; Wolf, Oliver T; Brüne, Martin

    2016-07-01

    Empathy is a fundamental attribute required for appropriate social functioning. The extent to which we empathize with others in pain is influenced by numerous factors. Being highly social species, humans face social stress on a regular basis, which undoubtedly affects how we react to our environment. It is not yet known how social stress may modulate our neural mechanisms when we empathize with others in painful circumstances, and its effects on empathic behavior are still unclear. For this reason, we recorded the electroencephalography (EEG) of healthy men and women, half of which were previously exposed to psychosocial stress, while they observed photographs of hands in painful and neutral situations. At the behavioral level, stress induced higher unpleasantness ratings to painful stimuli, and lower ratings to neutral pictures, independent of sex. At the neurophysiological level, we found that early (N110 over fronto-central sites) event-related potentials (ERPs) were not affected by stress, while late (P3 over centro-parietal regions) components showed a sex-dependent differential effect of stress. Correlation analyses further indicated a strong association between N110 with trait markers of empathy in all participants, while P3 was associated with the change in cortisol in stressed males. Our findings suggest that sex-dependent effects of social stress on the neural responses to empathy for pain give rise to comparable behaviors in men and women in the paradigm we employed, implying that each sex may engage in distinct mechanisms to cope with stress. Moreover, stress seems to modulate late neural mechanisms of empathy but not our early perception. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Correlation Between Stress and Quality of Life Experienced by Caregivers: Perception of a Group of Healthcare Professionals.

    Science.gov (United States)

    Silva, Bhárbara Karolline Rodrigues; Quaresma, Fernando Rodrigues Peixoto; Maciel, Erika da Silva; Figueiredo, Francisco Winter Dos Santos; Sarraf, Jonathan Souza; Adami, Fernando

    2017-01-01

    This study aims to evaluate the relationship between perceived level of stress and quality of life of professionals working in Prompt Service Units in the city of Palmas, Tocantins. A cross-sectional study was performed among 164 professionals from Prompt Service Units. Stress levels were evaluated using the Perceived Stress Scale. The WHOQOL-bref was used to evaluate the perception of quality of life. Quantitative variables distribution was evaluated using Shapiro-Wilk's test. For the analyses of correlations among perceived level of stress, total quality of life score, and the physical health domain of the WHOQOL-bref, Pearson's correlation test was applied. The significance level adopted for this trial was 95%. The study was approved by the Committee of Ethics in Research with Human Beings. When assessing the perceived level of stress with the total quality of life score, there was no significant correlation between those variables. However, there was an association between the perceived level of stress and the physical health domain of quality of life. Perceived quality of life was correlated with the physical health domain, and this result reinforces the importance of the facets that make up this area.

  16. Genotypic Correlation and Path Analysis of Some Traits related to Oil Yield and Grain Yield in Canola (Brassica napus L. under Non-stress and Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    A Ismaili

    2017-03-01

    Full Text Available Introduction Obtaining varieties with acceptable yield and tolerant to different arid and semi-arid climate condition of Iran is an important goal in canola breeding programs. Selection of genotypes base on one or more traits without regarding to correlation between them, could biases the expected results. Therefore, identifying of genetic correlation among traits especially in environmental stress condition is very important. The use of genotypic correlation helps evaluating the magnitude and direction of associations between characters facilitating the application of indirect selection, because genetic changes in a given trait may change other traits, leading to faster and larger genetic gains in plant breeding programs. Therefore, the selection for another trait may result in indirect response in the low heritable trait, provided the following conditions are satisfied: the genetic correlation between them is substantial, and the heritability of the secondary trait is greater than that of the primary trait. The purpose of this study was estimating the total genotypic variability, genotypic correlations, and path analysis among some important traits for selection criteria for improving seed and oil yield in canola under water deficit stress condition. Materials and Methods For evaluation of genetic correlation among traits and identifying important affecting traits on grain yield and oil yield in canola genotypes, an experiment was conducted based on a randomized complete blocks design with three replications in two different conditions of water deficit (stress and non-stress. Different traits were measured including seed yield, 1000-seed weight, number of seeds per pod, number of pods per plant, silique length, oil content, days to maturity, protein content, plant height and water use efficiency. Genotypic and phenotypic correlation coefficients were calculated for ten characters during growing seasons. The genotypic correlation coefficients

  17. Four-point correlation function of stress-energy tensors in N=4 superconformal theories

    CERN Document Server

    Korchemsky, G P

    2015-01-01

    We derive the explicit expression for the four-point correlation function of stress-energy tensors in four-dimensional N=4 superconformal theory. We show that it has a remarkably simple and suggestive form allowing us to predict a large class of four-point correlation functions involving the stress-energy tensor and other conserved currents. We then apply the obtained results on the correlation functions to computing the energy-energy correlations, which measure the flow of energy in the final states created from the vacuum by a source. We demonstrate that they are given by a universal function independent of the choice of the source. Our analysis relies only on N=4 superconformal symmetry and does not use the dynamics of the theory.

  18. Evaluation of Diversity and Traits Correlation in Spring Wheat Cultivars under Drought Stress

    Directory of Open Access Journals (Sweden)

    Mohammad Reza NAGHAVI

    2015-09-01

    Full Text Available In order to study of diversity and classify agro-morphological characters under normal irrigation and drought stress in spring wheat cultivars, 20 cultivars were evaluated in the research farm of University of Tabriz, Iran. According to the results, significant correlation was found between grain yield and number of spikes per plant, number of tiller per plant, number of fertile tillers, spike length, root length, root number, root volume, root diameter and root dry weight under both conditions. Moreover, 1,000 grain weight and plant dry weight had significant positive correlation with grain yield under drought stress. Factor analysis detected four and two factors which explained 96.77% and 90.59% of the total variation in normal irrigation and drought stress conditions, respectively. In drought stress condition the first factor justified 69.52% of total variation and was identified as yield factor. The second factor explained 21.07% of total variation and represented the biomass and plant height factor. Cluster analysis was based on the four and two factors obtained. According to the amount of factors for clusters obtained under drought stress, ‘Kavir’, ‘Niknejhad’, ‘Moghan 3’, ‘Darya’ and ‘Marvdasht’ were identified as the most drought tolerant cultivars. Other cluster was comprised of ‘Bahar’, ‘Pishtaz’, ‘Bam’, ‘Sepahan’, ‘Sistan’, ‘Pars’ and ‘Sivand’ and was named as the most sensitive under drought stress. Tolerant cultivars identified within the study can be used for direct culture or as genitors in breeding programs.

  19. Application of x-ray residual stress measurement to products

    International Nuclear Information System (INIS)

    Goto, T.; Iwamura, T.

    1975-01-01

    The X-ray residual stress measuring method is the only nondestructive method for measuring residual stress in polycrystalline materials. It is capable of obtaining information not only on macroscopic stress but also microscopic stress. The authors are employing this method for the development of pre-service and in-service inspection methods and for the improvement of various manufacturing techniques. In this paper, the results of measurement of some products as examples of its application are described. The examples introduced concern the following: (1) Selection of optimum conditions in heat treatment and stress-relief treatment. (2) Residual stress produced by mechanical processes such as autofrettage and flow form. (3) Check of manufacturing processes of rotary shaft and welded parts. (4) Estimation of fatigue strength of shot-peened part. (5) Detection of fatigue damage of shot-peened part. (auth.)

  20. A study on work stress, stress coping strategies and health promoting lifestyle among district hospital nurses in Taiwan.

    Science.gov (United States)

    Lee, Wei-Lun; Tsai, Shieunt-Han; Tsai, Chao-Wen; Lee, Chia-Ying

    2011-01-01

    To determine work stress, and stress-coping strategies, and to analyze their the relationships in order to improve health-promoting lifestyle of nurses in Taiwan. Three hundred eighty-five nurses who had work experience for more than 6 mo, were selected from four district hospitals in Kaohsiung and Ping Tung. We used a stratified cluster random sampling method for the selection. The nurses answered a self-report questionnaire, which was categorized into four sections: personal background data, work stress, stress-coping strategies, and health-promoting lifestyle. The findings indicate work stress and the health promoting lifestyle of nurses are at a higher level, with stress-coping strategies being at a medium level. Work stress and stress-coping strategies were significantly and positively correlated. Professional relationships, managerial role, personal responsibility, and recognition of work stress and the responsibilities of a health-promoting lifestyle were negatively correlated. Managerial role, personal responsibility, and organizational atmosphere of work stress as well as realization, an item of health-promoting lifestyle, were negatively correlated. Recognition of work stress and stress management, items of health-promoting lifestyle, were negatively correlated. Health responsibility, and self-actualization, items of health-promoting lifestyle, as well as stress-coping strategies were negatively correlated. Nutrition, an item of health-promoting lifestyle, and the support stress-coping strategy was negatively correlated. Nurses have greater work pressure and better work stress-coping strategies, but worse health responsibility and realization of a health-promoting lifestyle. We suggest hospitals build good relationships and appropriately increase employment of nurses through a good work atmosphere to achieve nurses' realization of a health-promoting lifestyle.

  1. [NEUROSEMANTIC AND PSYCHOPHYSIOLOGICAL CORRELATES OF RHYTHM-SUGGESTIVE CORRECTION OF STRESS CONDITIONS].

    Science.gov (United States)

    Ushakov, I B; Ivanov, A V; Kvasovets, S V; Bubeev, Yu A

    2015-01-01

    Correlates of successful rhythm-suggestive compensation of stress in sportsmen with neurotic symptoms developed in consequence of painful experience of failure were studied. Effectiveness of the rhythm-suggestive and rational psychological methods was compared by measuring the evoked potentials response to emotionally significant extramental verbal stimuli and images, and using psychophysiological test MASTER to track dynamics of a number of body functional parameters. The rational compensation has been shown to reduce the psychic tension and to set right the voluntary control process. Rhythm-suggestive programs are good for compensation of post-stress emotions and affectations, and the involuntary control process. It was found that correction potentialities of the rhythm-suggestive programs together with the psychodiagnostic advantages of test MASTER are promising instruments for dynamic monitoring of the mental state with the aim to prevent workplace stresses and to provide rehabilitation treatment of aftermaths.

  2. The relationship between the statistics of open ocean currents and the temporal correlations of the wind stress

    International Nuclear Information System (INIS)

    Bel, Golan; Ashkenazy, Yosef

    2013-01-01

    We study the statistics of wind-driven open ocean currents. Using the Ekman layer model for the integrated currents, we investigate analytically and numerically the relationship between the wind-stress distribution and its temporal correlations and the statistics of the open ocean currents. We found that temporally long-range correlated winds result in currents whose statistics is proportional to the wind-stress statistics. On the other hand, short-range correlated winds lead to Gaussian distributions of the current components, regardless of the stationary distribution of the winds, and therefore to a Rayleigh distribution of the current amplitude, if the wind stress is isotropic. We found that the second moment of the current speed exhibits a maximum as a function of the correlation time of the wind stress for a non-zero Coriolis parameter. The results were validated using an oceanic general circulation model. (paper)

  3. Relationship among perceived stress, anxiety, depression and craniocervical pain in nursing professionals under stress at work

    Directory of Open Access Journals (Sweden)

    Daniela Pozzebon

    Full Text Available Abstract Introduction: The appearance and evolution of some clinical pain conditions may be influenced by stress and other psychosocial factors. Face, head and cervical muscles may increase their activity and tension in the presence of stress, leading to craniocervicomandibular pain in individuals exposed to stress. Objective: To assess the relationship among perceived stress, anxiety, depression and craniocervicomandibular pain in nursing professionals under stress at work. Materials and Methods: Forty-three women under stress at work, according to the Job Stress Scale (JSS, were assessed by the Perceived Stress Scale (PSS, the Hospital Anxiety and Depression Scale (HADS, pressure pain threshold, measured by algometry, and muscle sensitivity to hand palpation of the masticatory and cervical muscles. Results: A low moderate level of perceived stress was found in 62.79% of the sample, anxiety in 11.63% and depression in 9.30%. The psychosocial scales correlated with each other. No correlation was found between pressure pain threshold and perceived stress, anxiety and depression. The level of pain to hand palpation correlated with the perceived stress scores. Conclusion: Pressure pain threshold was not influenced by the psychosocial factors assessed. Pain intensity to hand palpation, however, was higher as the perception of stress increased.

  4. Prediction of life stress on athletes’ burnout: the dual role of perceived stress

    OpenAIRE

    Chyi, Theresa; Lu, Frank Jing-Horng; Wang, Erica T.W.; Hsu, Ya-Wen; Chang, Ko-Hsin

    2018-01-01

    Although many studies adopted Smith’s (1986) cognitive–affective model of athletic burnout in examining stress–burnout relationship, very few studies examined the mediating/moderating role of perceived stress on the stress–burnout relationship. We sampled 195 college student-athletes and assessed their life stress, perceived stress, and burnout. Correlation analyses found all study variables correlated. Two separate hierarchical regression analyses found that the “distress” component of perce...

  5. Computational stress and damage modelling for rolling contact fatigue

    DEFF Research Database (Denmark)

    Cerullo, Michele

    Rolling contact fatigue in radial roller bearings is studied by means of a 2D plane strain nite element program. The Dang Van multiaxial fatigue criterion is firstly used, in a macroscopic study modeling the bearing raceway, to investigate the region where fatigue cracks are more likely to nucleate...... and of compressive residual stresses are also analyzed. The stress history of a material point at the depth where the maximum Dang Van damage factor is reached is then recorded and used in a subsequent micro-mechanical analysis. The stress history is applied as periodic boundary conditions in a representative volume...

  6. Cement stress predictions after anatomic total shoulder arthroplasty are correlated with preoperative glenoid bone quality.

    Science.gov (United States)

    Terrier, Alexandre; Obrist, Raphaël; Becce, Fabio; Farron, Alain

    2017-09-01

    We hypothesized that biomechanical parameters typically associated with glenoid implant failure after anatomic total shoulder arthroplasty (aTSA) would be correlated with preoperative glenoid bone quality. We developed an objective automated method to quantify preoperative glenoid bone quality in different volumes of interest (VOIs): cortical bone, subchondral cortical plate, subchondral bone after reaming, subchondral trabecular bone, and successive layers of trabecular bone. Average computed tomography (CT) numbers (in Hounsfield units [HU]) were measured in each VOI from preoperative CT scans. In parallel, we built patient-specific finite element models of simulated aTSAs to predict cement stress, bone-cement interfacial stress, and bone strain around the glenoid implant. CT measurements and finite element predictions were obtained for 20 patients undergoing aTSA for primary glenohumeral osteoarthritis. We tested all linear correlations between preoperative patient characteristics (age, sex, height, weight, glenoid bone quality) and biomechanical predictions (cement stress, bone-cement interfacial stress, bone strain). Average CT numbers gradually decreased from cortical (717 HU) to subchondral and trabecular (362 HU) bone. Peak cement stress (4-10 MPa) was located within the keel hole, above the keel, or behind the glenoid implant backside. Cement stress, bone-cement interfacial stress, and bone strain were strongly negatively correlated with preoperative glenoid bone quality, particularly in VOIs behind the implant backside (subchondral trabecular bone) but also in deeper trabecular VOIs. Our numerical study suggests that preoperative glenoid bone quality is an important parameter to consider in aTSA, which may be associated with aseptic loosening of the glenoid implant. These initial results should now be confronted with clinical and radiologic outcomes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc

  7. Does oxidative stress shorten telomeres?

    NARCIS (Netherlands)

    Boonekamp, Jelle J.; Bauch, Christina; Mulder, Ellis; Verhulst, Simon

    Oxidative stress shortens telomeres in cell culture, but whether oxidative stress explains variation in telomere shortening in vivo at physiological oxidative stress levels is not well known. We therefore tested for correlations between six oxidative stress markers and telomere attrition in nestling

  8. Occupational Stress among Teachers.

    Science.gov (United States)

    Albertson, Larry M.; Kagan, Dona M.

    1987-01-01

    Two studies were conducted to investigate the degree to which occupational stress among teachers could be attributed to personal characteristics of the individuals themselves. The first study developed dispositional stress scales. The second examined correlations between these scales, occupational stress scales, and teachers' attitudes toward…

  9. Bulk stress auto-correlation function in simple liquids-sum rules

    International Nuclear Information System (INIS)

    Tankeshwar, K.; Bhandari, R.; Pathak, K.N.

    1990-10-01

    Expressions for the zeroth, second and fourth frequency sum rules of the bulk stress auto correlation function have been derived. The exact expressions involve static correlation function up to four particles. Because of the non availability of any information about static quadruplet correlation function we use a low order decoupling approximation for this. In this work, we have obtained, separately, the sum rules for the different mechanism of momentum transfer in the fluids. The results are expected to be useful in the study of bulk viscosity of the fluids. (author). 9 refs

  10. Clinical correlates of parenting stress in children with Tourette syndrome and in typically developing children.

    Science.gov (United States)

    Stewart, Stephanie B; Greene, Deanna J; Lessov-Schlaggar, Christina N; Church, Jessica A; Schlaggar, Bradley L

    2015-05-01

    To determine the impact of tic severity in children with Tourette syndrome on parenting stress and the impact of comorbid attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) symptomatology on parenting stress in both children with Tourette syndrome and typically developing children. Children with diagnosed Tourette syndrome (n=74) and tic-free typically developing control subjects (n=48) were enrolled in a cross-sectional study. Parenting stress was greater in the group with Tourette syndrome than the typically developing group. Increased levels of parenting stress were related to increased ADHD symptomatology in both children with Tourette syndrome and typically developing children. Symptomatology of OCD was correlated with parenting stress in Tourette syndrome. Parenting stress was independent of tic severity in patients with Tourette syndrome. For parents of children with Tourette syndrome, parenting stress appears to be related to the child's ADHD and OCD comorbidity and not to the severity of the child's tic. Subthreshold ADHD symptomatology also appears to be related to parenting stress in parents of typically developing children. These findings demonstrate that ADHD symptomatology impacts parental stress both in children with and without a chronic tic disorder. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Prevalence and correlates of job stress among junior doctors in the ...

    African Journals Online (AJOL)

    Prevalence and correlates of job stress among junior doctors in the ... Journal Home > Vol 14, No 2 (2016) > ... Descriptive statistics were generated. ... 61.3% were males, 59% had spent less than 5 years in medical practice, and 34.8% were ...

  12. Oxidative stress at high altitude: genotype–phenotype correlations

    Directory of Open Access Journals (Sweden)

    Pandey P

    2014-05-01

    Full Text Available Priyanka Pandey,1,2 MA Qadar Pasha1,2 1CSIR-Institute of Genomics and Integrative Biology, Delhi, India; 2Department of Biotechnology, University of Pune, Ganeshkhind, Pune, India Abstract: It has been well-documented that the hypobaric hypoxic environment at high altitude (HA causes stress to both the permanent residents of HA and the sojourners. This oxidative stress primarily disturbs the oxygen-sensing and vascular homeostasis pathways, thereby upsetting normal human physiology, especially in sojourners. These environmental challenges have caused dynamic evolutionary changes within natives of HA, allowing them to develop adaptive plasticity. This review focuses on the genomic and biochemical features of the molecules involved in the oxygen-sensing and vascular homeostasis pathways with respect to HA pulmonary edema (HAPE and adaptation. We review the role of genetic markers such as HIF-prolyl hydroxylase 2, endothelial PAS domain-containing protein 1, endothelial nitric oxide synthase, endothelin 1, cytochrome b-245 alpha polypeptide, and glutathione S-transferase pi 1, as well as three circulatory biomarkers (nitric oxide, endothelin 1, and 8-iso-prostaglandin F2α, by highlighting approaches such as candidate gene and genome-wide, adopted in deciphering the pathways. A disagreement between the two approaches has also been highlighted. In addition, we discuss that an overrepresentation of wild-type alleles in HA natives and mutant alleles of same polymorphisms in HAPE patients implies that the allelic variants at the same locus are involved in adaptation and HAPE, respectively. Moreover, healthy sojourners present a number of genomic features similar to HA natives, further strengthening the concept of genetic predisposition. A trend in correlation between protective and risk alleles and altered levels of circulatory markers clearly documents the phenomenon of genotype–phenotype correlations. We conclude that the genetic and biochemical

  13. Effects of stress on heart rate complexity--a comparison between short-term and chronic stress.

    Science.gov (United States)

    Schubert, C; Lambertz, M; Nelesen, R A; Bardwell, W; Choi, J-B; Dimsdale, J E

    2009-03-01

    This study examined chronic and short-term stress effects on heart rate variability (HRV), comparing time, frequency and phase domain (complexity) measures in 50 healthy adults. The hassles frequency subscale of the combined hassles and uplifts scale (CHUS) was used to measure chronic stress. Short-term stressor reactivity was assessed with a speech task. HRV measures were determined via surface electrocardiogram (ECG). Because respiration rate decreased during the speech task (pshort-term stress decreased HR D2 (calculated via the pointwise correlation dimension PD2) (pshort-term stress. Partial correlation adjusting for respiration rate showed that HR D2 was associated with chronic stress (r=-.35, p=.019). Differential effects of chronic and short-term stress were observed on several HRV measures. HR D2 decreased under both stress conditions reflecting lowered functionality of the cardiac pacemaker. The results confirm the importance of complexity metrics in modern stress research on HRV.

  14. Analysis of structural correlations in a model binary 3D liquid through the eigenvalues and eigenvectors of the atomic stress tensors

    International Nuclear Information System (INIS)

    Levashov, V. A.

    2016-01-01

    It is possible to associate with every atom or molecule in a liquid its own atomic stress tensor. These atomic stress tensors can be used to describe liquids’ structures and to investigate the connection between structural and dynamic properties. In particular, atomic stresses allow to address atomic scale correlations relevant to the Green-Kubo expression for viscosity. Previously correlations between the atomic stresses of different atoms were studied using the Cartesian representation of the stress tensors or the representation based on spherical harmonics. In this paper we address structural correlations in a 3D model binary liquid using the eigenvalues and eigenvectors of the atomic stress tensors. This approach allows to interpret correlations relevant to the Green-Kubo expression for viscosity in a simple geometric way. On decrease of temperature the changes in the relevant stress correlation function between different atoms are significantly more pronounced than the changes in the pair density function. We demonstrate that this behaviour originates from the orientational correlations between the eigenvectors of the atomic stress tensors. We also found correlations between the eigenvalues of the same atomic stress tensor. For the studied system, with purely repulsive interactions between the particles, the eigenvalues of every atomic stress tensor are positive and they can be ordered: λ 1 ≥ λ 2 ≥ λ 3 ≥ 0. We found that, for the particles of a given type, the probability distributions of the ratios (λ 2 /λ 1 ) and (λ 3 /λ 2 ) are essentially identical to each other in the liquids state. We also found that λ 2 tends to be equal to the geometric average of λ 1 and λ 3 . In our view, correlations between the eigenvalues may represent “the Poisson ratio effect” at the atomic scale.

  15. Analysis of structural correlations in a model binary 3D liquid through the eigenvalues and eigenvectors of the atomic stress tensors

    Energy Technology Data Exchange (ETDEWEB)

    Levashov, V. A. [Technological Design Institute of Scientific Instrument Engineering, Novosibirsk 630058 (Russian Federation)

    2016-03-07

    It is possible to associate with every atom or molecule in a liquid its own atomic stress tensor. These atomic stress tensors can be used to describe liquids’ structures and to investigate the connection between structural and dynamic properties. In particular, atomic stresses allow to address atomic scale correlations relevant to the Green-Kubo expression for viscosity. Previously correlations between the atomic stresses of different atoms were studied using the Cartesian representation of the stress tensors or the representation based on spherical harmonics. In this paper we address structural correlations in a 3D model binary liquid using the eigenvalues and eigenvectors of the atomic stress tensors. This approach allows to interpret correlations relevant to the Green-Kubo expression for viscosity in a simple geometric way. On decrease of temperature the changes in the relevant stress correlation function between different atoms are significantly more pronounced than the changes in the pair density function. We demonstrate that this behaviour originates from the orientational correlations between the eigenvectors of the atomic stress tensors. We also found correlations between the eigenvalues of the same atomic stress tensor. For the studied system, with purely repulsive interactions between the particles, the eigenvalues of every atomic stress tensor are positive and they can be ordered: λ{sub 1} ≥ λ{sub 2} ≥ λ{sub 3} ≥ 0. We found that, for the particles of a given type, the probability distributions of the ratios (λ{sub 2}/λ{sub 1}) and (λ{sub 3}/λ{sub 2}) are essentially identical to each other in the liquids state. We also found that λ{sub 2} tends to be equal to the geometric average of λ{sub 1} and λ{sub 3}. In our view, correlations between the eigenvalues may represent “the Poisson ratio effect” at the atomic scale.

  16. The analysis of stress reactions ana coping patterns of cancer patients who perceived stress by radiotherapy

    International Nuclear Information System (INIS)

    Bang, Dong Han; Kim, Jin Su; Park, Gil Yong; Son, Mi Suk

    2001-01-01

    This study is performed to encourage cancer patients to identify, relieve and effectively overcome the stress caused by radiotherapy, by analyzing stress reactions and coping patterns of cancer patients who perceived stress due to radiotherapy. The study group was composed of 85 cancer patients of the age 20 or higher who were undergoing radiotherapy in four hospitals located in Seoul and Kyonggi-do. The survey questionnaire was used, which had 161 questions inquiring respondents of general status, perceived stress, stress reactions and coping patterns. The surveyed data were analyzed by a SAS program, which employed descriptive statistics. Pearson Correlation Coefficient, t-test, ANOVA and Stepwised Multiple Regression. The stress perception and reaction rates were low in cancer patients comparing to patients of the other study. In the coping patterns. the problem-focused coping patterns were significantly higher than emotion-focused coping patterns. The statistically meaningful differences were observed in the stress perception and reactions depending on the time of diagnosis and perceived health level. As for the problem-focused coping patterns, significant differences were found depending on age, marital status, education, income and the number of family members as well as perceived health level of patients. The level of perceived stress and that of stress reactions was found to have positively significant correlation(r=.764, p<.001) while the perceived stress and the problem-focused coping patterns was correlated negatively (r=-.288, p<.01). The stress reactions and the problem-focused coping patterns was found to have negatively significant correlation(r=-.289, p<.01). The problem-focused coping behavior, which cooperated with doctors, technologists, nurses and families of cancer patients, is advisable for the cancer patients to overcome uncertainty and uneasiness by effectively release the stress.

  17. The analysis of stress reactions ana coping patterns of cancer patients who perceived stress by radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Dong Han; Kim, Jin Su; Park, Gil Yong; Son, Mi Suk [Dept. of Radiation Oncology, Bundang CHA General Hospital, College of Medicine, Pochon CHA University, Sungnam (Korea, Republic of)

    2001-12-15

    This study is performed to encourage cancer patients to identify, relieve and effectively overcome the stress caused by radiotherapy, by analyzing stress reactions and coping patterns of cancer patients who perceived stress due to radiotherapy. The study group was composed of 85 cancer patients of the age 20 or higher who were undergoing radiotherapy in four hospitals located in Seoul and Kyonggi-do. The survey questionnaire was used, which had 161 questions inquiring respondents of general status, perceived stress, stress reactions and coping patterns. The surveyed data were analyzed by a SAS program, which employed descriptive statistics. Pearson Correlation Coefficient, t-test, ANOVA and Stepwised Multiple Regression. The stress perception and reaction rates were low in cancer patients comparing to patients of the other study. In the coping patterns. the problem-focused coping patterns were significantly higher than emotion-focused coping patterns. The statistically meaningful differences were observed in the stress perception and reactions depending on the time of diagnosis and perceived health level. As for the problem-focused coping patterns, significant differences were found depending on age, marital status, education, income and the number of family members as well as perceived health level of patients. The level of perceived stress and that of stress reactions was found to have positively significant correlation(r=.764, p<.001) while the perceived stress and the problem-focused coping patterns was correlated negatively (r=-.288, p<.01). The stress reactions and the problem-focused coping patterns was found to have negatively significant correlation(r=-.289, p<.01). The problem-focused coping behavior, which cooperated with doctors, technologists, nurses and families of cancer patients, is advisable for the cancer patients to overcome uncertainty and uneasiness by effectively release the stress.

  18. Canonical correlation analysis of professional stress,social support,and professional burnout among low-rank army officers

    Directory of Open Access Journals (Sweden)

    Chuan-yun LI

    2011-12-01

    Full Text Available Objective The present study investigates the influence of professional stress and social support on professional burnout among low-rank army officers.Methods The professional stress,social support,and professional burnout scales among low-rank army officers were used as test tools.Moreover,the officers of established units(battalion,company,and platoon were chosen as test subjects.Out of the 260 scales sent,226 effective scales were received.The descriptive statistic and canonical correlation analysis models were used to analyze the influence of each variable.Results The scores of low-rank army officers in the professional stress,social support,and professional burnout scales were more than average,except on two factors,namely,interpersonal support and de-individualization.The canonical analysis identified three groups of canonical correlation factors,of which two were up to a significant level(P < 0.001.After further eliminating the social support variable,the canonical correlation analysis of professional stress and burnout showed that the canonical correlation coefficients P corresponding to 1 and 2 were 0.62 and 0.36,respectively,and were up to a very significant level(P < 0.001.Conclusion The low-rank army officers experience higher professional stress and burnout levels,showing a lower sense of accomplishment,emotional exhaustion,and more serious depersonalization.However,social support can reduce the onset and seriousness of professional burnout among these officers by lessening pressure factors,such as career development,work features,salary conditions,and other personal factors.

  19. Correlation between vortices and wall shear stress in a curved artery model under pulsatile flow conditions

    Science.gov (United States)

    Cox, Christopher; Plesniak, Michael W.

    2017-11-01

    One of the most physiologically relevant factors within the cardiovascular system is the wall shear stress. The wall shear stress affects endothelial cells via mechanotransduction and atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the shear stress is both oscillatory and multidirectional. Also, the combined effect of curvature and pulsatility in cardiovascular flows produces unsteady vortices. In this work, our goal is to assess the correlation between multiple vortex pairs and wall shear stress. To accomplish this, we use an in-house high-order flux reconstruction Navier-Stokes solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180° curved artery model. We use a physiologically relevant flow rate and generate results using both fully developed and uniform entrance conditions, the latter motivated by the fact that flow upstream to a curved artery may not be fully developed. Under these two inflow conditions, we characterize the evolution of various vortex pairs and their subsequent effect on several wall shear stress metrics. Supported by GW Center for Biomimetics and Bioinspired Engineering.

  20. Sex-reversed correlation between stress levels and dominance rank in a captive non-breeder flock of crows.

    Science.gov (United States)

    Ode, Minami; Asaba, Akari; Miyazawa, Eri; Mogi, Kazutaka; Kikusui, Takefumi; Izawa, Ei-Ichi

    2015-07-01

    Group living has both benefits and costs to individuals; benefits include efficient acquisition of resources, and costs include stress from social conflicts among group members. Such social challenges result in hierarchical dominance ranking among group members as a solution to avoid escalating conflict that causes different levels of basal stress between individuals at different ranks. Stress-associated glucocorticoid (corticosterone in rodents and birds; CORT) levels are known to correlate with dominance rank in diverse taxa and to covary with various social factors, such as sex and dominance maintenance styles. Although there is much evidence for sex differences in the basal levels of CORT in various species, the correlation of sex differences in basal CORT with dominance rank is poorly understood. We investigated the correlation between CORT metabolites (CM) in the droppings and social factors, including rank and sex, in a captive non-breeder group of crows. In this group, all the single males dominated all the single females, and dominance ranks were stable among single males but relatively unstable among single females. CM levels and rank were significantly correlated in a sex-reversed fashion: males at higher rank (i.e., more dominant) had higher CM, whereas females at higher rank exhibited lower CM. This is the first evidence of sex-reversed patterns of CM-rank correlation in birds. The results suggest that different mechanisms of stress-dominance relationships operate on the sexes in non-breeder crow aggregations; in males, stress is associated with the cost of aggressive displays, whereas females experience subordination stress due to males' overt aggression. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. [Correlations of central nervous system and thyroid function under chronic emotional stress].

    Science.gov (United States)

    Amiragova, M G; Arkhangel'skaia, M I

    1982-06-01

    Experiments on cats exposed to chronic emotional stress induced during one week by 4-hour immobilization of the animals in conjunction with aperiodic electrocutaneous stimulation were made to study correlations of the time course of changes in the EEG of the cortical and subcortical structures and the content of thyroxin in the peripheral blood at varying time of the experiments. It was demonstrated that in the course of stress, the EEG manifests the cycles of "burst" activity of slow waves, which are first recorded in the posterior hypothalamus and then get generalized. This is accompanied by a significantly high thyroxin secretion. As the stress exposures are repeated, the EEG changes become dominant, also corresponding with high thyroxin secretion. After the experiments are over, the cycles of "burst" activity accompanied by enhanced thyroid function are still recordable over several days.

  2. Residual stresses measurement by using ring-core method and 3D digital image correlation technique

    International Nuclear Information System (INIS)

    Hu, Zhenxing; Xie, Huimin; Zhu, Jianguo; Wang, Huaixi; Lu, Jian

    2013-01-01

    Ring-core method/three-dimensional digital image correlation (3D DIC) residual stresses measurement is proposed. Ring-core cutting is a mechanical stress relief method, and combining with 3D DIC system the deformation of the specimen surface can be measured. An optimization iteration method is proposed to obtain the residual stress and rigid-body motion. The method has the ability to cut an annular trench at a different location out of the field of view. A compression test is carried out to demonstrate how residual stress is determined by using 3D DIC system and outfield measurement. The results determined by the approach are in good agreement with the theoretical value. Ring-core/3D DIC has shown its robustness to determine residual stress and can be extended to application in the engineering field. (paper)

  3. Macroscopic effects of the quantum trace anomaly

    International Nuclear Information System (INIS)

    Mottola, Emil; Vaulin, Ruslan

    2006-01-01

    The low energy effective action of gravity in any even dimension generally acquires nonlocal terms associated with the trace anomaly, generated by the quantum fluctuations of massless fields. The local auxiliary field description of this effective action in four dimensions requires two additional scalar fields, not contained in classical general relativity, which remain relevant at macroscopic distance scales. The auxiliary scalar fields depend upon boundary conditions for their complete specification, and therefore carry global information about the geometry and macroscopic quantum state of the gravitational field. The scalar potentials also provide coordinate invariant order parameters describing the conformal behavior and divergences of the stress tensor on event horizons. We compute the stress tensor due to the anomaly in terms of its auxiliary scalar potentials in a number of concrete examples, including the Rindler wedge, the Schwarzschild geometry, and de Sitter spacetime. In all of these cases, a small number of classical order parameters completely determine the divergent behaviors allowed on the horizon, and yield qualitatively correct global approximations to the renormalized expectation value of the quantum stress tensor

  4. Casimir stress in materials: Hard divergency at soft walls

    Science.gov (United States)

    Griniasty, Itay; Leonhardt, Ulf

    2017-11-01

    The Casimir force between macroscopic bodies is well understood, but not the Casimir stress inside bodies. Suppose empty space or a uniform medium meets a soft wall where the refractive index is continuous but its derivative jumps. For this situation we predict a characteristic power law for the stress inside the soft wall and close to its edges. Our result shows that such edges are not tolerated in the aggregation of liquids at surfaces, regardless whether the liquid is attracted or repelled.

  5. Psychosocial versus physiological stress – meta-analyses on deactivations and activations of the neural correlates of stress reactions

    Science.gov (United States)

    Kogler, Lydia; Mueller, Veronika I.; Chang, Amy; Eickhoff, Simon B.; Fox, Peter T.; Gur, Ruben C.; Derntl, Birgit

    2015-01-01

    Stress is present in everyday life in various forms and situations. Two stressors frequently investigated are physiological and psychosocial stress. Besides similar subjective and hormonal responses, it has been suggested that they also share common neural substrates. The current study used activation-likelihood-estimation meta-analysis to test this assumption by integrating results of previous neuroimaging studies on stress processing. Reported results are cluster-level FWE corrected. The inferior frontal gyrus (IFG) and the anterior insula (AI) were the only regions that demonstrated overlapping activation for both stressors. Analysis of physiological stress showed consistent activation of cognitive and affective components of pain processing such as the insula, striatum, or the middle cingulate cortex. Contrarily, analysis across psychosocial stress revealed consistent activation of the right superior temporal gyrus and deactivation of the striatum. Notably, parts of the striatum appeared to be functionally specified: the dorsal striatum was activated in physiological stress, whereas the ventral striatum was deactivated in psychosocial stress. Additional functional connectivity and decoding analyses further characterized this functional heterogeneity and revealed higher associations of the dorsal striatum with motor regions and of the ventral striatum with reward processing. Based on our meta-analytic approach, activation of the IFG and the AI seems to indicate a global neural stress reaction. While physiological stress activates a motoric fight-or-flight reaction, during psychosocial stress attention is shifted towards emotion regulation and goal-directed behavior, and reward processing is reduced. Our results show the significance of differentiating physiological and psychosocial stress in neural engagement. Furthermore, the assessment of deactivations in addition to activations in stress research is highly recommended. PMID:26123376

  6. The effect of academic stress and attachment stress on stress-eaters and stress-undereaters.

    Science.gov (United States)

    Emond, Michael; Ten Eycke, Kayla; Kosmerly, Stacey; Robinson, Adele Lafrance; Stillar, Amanda; Van Blyderveen, Sherry

    2016-05-01

    It is well established that stress is related to changes in eating patterns. Some individuals are more likely to increase their overall food intake under conditions of stress, whereas others are more likely to consume less food when stressed. Attachment style has been linked to disordered eating and eating disorders; however, comparisons of eating behaviors under attachment versus other types of stress have yet to be explored. The present laboratory study examined the eating patterns in self-identified stress-undereaters and stress-eaters under various types of stress. More specifically, the study examined the effects of academic and attachment stress on calorie, carbohydrate and sugar consumption within these two groups. Under the guise of critiquing student films, university students viewed either one of two stress-inducing videos (academic stress or attachment stress, both designed to be emotionally arousing) or a control video (designed to be emotionally neutral), and their food intake was recorded. Results demonstrated that the video manipulations were effective in inducing stress. Differential patterns of eating were noted based on group and stress condition. Specifically, stress-undereaters ate fewer calories, carbohydrates and sugars than stress-eaters in the academic stress condition, but not in the attachment stress or control condition. Findings suggest that specific types of stressors may influence eating behaviors differently. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Neural correlates of stress and favorite-food cue exposure in adolescents: a functional magnetic resonance imaging study.

    Science.gov (United States)

    Hommer, Rebecca E; Seo, Dongju; Lacadie, Cheryl M; Chaplin, Tara M; Mayes, Linda C; Sinha, Rajita; Potenza, Marc N

    2013-10-01

    Adolescence is a critical period of neurodevelopment for stress and appetitive processing, as well as a time of increased vulnerability to stress and engagement in risky behaviors. This study was conducted to examine brain activation patterns during stress and favorite-food-cue experiences relative to a neutral-relaxing condition in adolescents. Functional magnetic resonance imaging was employed using individualized script-driven guided imagery to compare brain responses with such experiences in 43 adolescents. Main effects of condition and gender were found, without a significant gender-by-condition interaction. Stress imagery, relative to neutral, was associated with activation in the caudate, thalamus, left hippocampus/parahippocampal gyrus, midbrain, left superior/middle temporal gyrus, and right posterior cerebellum. Appetitive imagery of favorite food was associated with caudate, thalamus, and midbrain activation compared with the neutral-relaxing condition. To understand neural correlates of anxiety and craving, subjective (self-reported) measures of stress-induced anxiety and favorite-food-cue-induced craving were correlated with brain activity during stress and appetitive food-cue conditions, respectively. High self-reported stress-induced anxiety was associated with hypoactivity in the striatum, thalamus, hippocampus, and midbrain. Self-reported favorite-food-cue-induced craving was associated with blunted activity in cortical-striatal regions, including the right dorsal and ventral striatum, medial prefrontal cortex, motor cortex, and left anterior cingulate cortex. These findings in adolescents indicate the activation of predominantly subcortical-striatal regions in the processing of stressful and appetitive experiences and link hypoactive striatal circuits to self-reported stress-induced anxiety and cue-induced favorite-food craving. Copyright © 2012 Wiley Periodicals, Inc.

  8. Midwifery and nursing students' communication skills and life orientation: correlation with stress coping approaches.

    Science.gov (United States)

    Ozdemir, Gülsün; Kaya, Hatice

    2013-06-01

    Methods learnt by nursing and midwifery students' such as communication skills, optimisim and coping with stress would be used in their profeesional life. It is very important to promote their positive thinking and communication skills to raise coping with stress. This cross sectional study was performed to examine the nursing and midwifery students' communication skills and optimistic life orientation and its correlation with coping strategies with stress. The study population included 2572 students who were studying in departments of nursing and midwifery in Istanbul. The sample was included 1419 students. Three questionnaires including Communication Skills Test, Life Orientation Test and Ways of Coping Inventory were used for data collection. The data were evaluated by calculating frequency, percentage, arithmetic mean, standard deviation and Pearson correlation coefficient. Students' total mean score from the Communication Skills Scale was 165.27 ± 15.39 and for the Life Orientation Test was 18.51 ± 4.54. There was a positive correlation between their Life Orientation scores and the scores for self confidence (r = 0.34, P students in optimistic life orientation and communication skills increased self confidence approach, optimistic, and social support seeking scores increased, whereas helpless, and submissive scores decreased.

  9. Significance of radiographic abnormalities in patients with tibial stress injuries: correlation with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kijowski, Richard; Choi, James; Smet, Arthur de; Mukharjee, Rajat

    2007-01-01

    The objective was to correlate radiographic findings with magnetic resonance imaging (MRI) findings in patients with suspected tibial stress injuries in order to determine the significance of radiographic signs of stress injury in these individuals. The study group consisted of 80 patients with suspected tibial stress injuries who underwent a radiographic and MR examination of the tibia. Nineteen patients had bilateral involvement. Thus, a total of 99 tibias were evaluated. All radiographs and MR examinations were retrospectively reviewed, 1 month apart, in consensus by two musculoskeletal radiologists. The radiographs were reviewed without knowledge of the site of the clinical symptoms. Fisher's exact tests were used to determine the association between a positive radiograph and the presence of various MRI signs of a high-grade stress injury. There was a strong association between the presence of periosteal reaction on radiographs at the site of the clinical symptoms and a Fredericson grade 4 stress injury on MRI. The presence of periosteal reaction on radiographs at the site of clinical symptoms is predictive of a high-grade stress injury by MRI criteria. (orig.)

  10. The impact of acute psychosocial stress on magnetoencephalographic correlates of emotional attention and exogenous visual attention.

    Directory of Open Access Journals (Sweden)

    Ludger Elling

    Full Text Available Stress-induced acute activation of the cerebral catecholaminergic systems has often been found in rodents. However, little is known regarding the consequences of this activation on higher cognitive functions in humans. Theoretical inferences would suggest increased distractibility in the sense of increased exogenous attention and emotional attention. The present study investigated the influence of acute stress responses on magnetoencephalographic (MEG correlates of visual attention. Healthy male subjects were presented emotional and neutral pictures in three subsequent MEG recording sessions after being exposed to a TSST-like social stressor, intended to trigger a HPA-response. The subjects anticipation of another follow-up stressor was designed to sustain the short-lived central catecholaminergic stress reactions throughout the ongoing MEG recordings. The heart rate indicates a stable level of anticipatory stress during this time span, subsequent cortisol concentrations and self-report measures of stress were increased. With regard to the MEG correlates of attentional functions, we found that the N1m amplitude remained constantly elevated during stressor anticipation. The magnetic early posterior negativity (EPNm was present but, surprisingly, was not at all modulated during stressor anticipation. This suggests that a general increase of the influence of exogenous attention but no specific effect regarding emotional attention in this time interval. Regarding the time course of the effects, an influence of the HPA on these MEG correlates of attention seems less likely. An influence of cerebral catecholaminergic systems is plausible, but not definite.

  11. The impact of acute psychosocial stress on magnetoencephalographic correlates of emotional attention and exogenous visual attention.

    Science.gov (United States)

    Elling, Ludger; Schupp, Harald; Bayer, Janine; Bröckelmann, Ann-Kathrin; Steinberg, Christian; Dobel, Christian; Junghofer, Markus

    2012-01-01

    Stress-induced acute activation of the cerebral catecholaminergic systems has often been found in rodents. However, little is known regarding the consequences of this activation on higher cognitive functions in humans. Theoretical inferences would suggest increased distractibility in the sense of increased exogenous attention and emotional attention. The present study investigated the influence of acute stress responses on magnetoencephalographic (MEG) correlates of visual attention. Healthy male subjects were presented emotional and neutral pictures in three subsequent MEG recording sessions after being exposed to a TSST-like social stressor, intended to trigger a HPA-response. The subjects anticipation of another follow-up stressor was designed to sustain the short-lived central catecholaminergic stress reactions throughout the ongoing MEG recordings. The heart rate indicates a stable level of anticipatory stress during this time span, subsequent cortisol concentrations and self-report measures of stress were increased. With regard to the MEG correlates of attentional functions, we found that the N1m amplitude remained constantly elevated during stressor anticipation. The magnetic early posterior negativity (EPNm) was present but, surprisingly, was not at all modulated during stressor anticipation. This suggests that a general increase of the influence of exogenous attention but no specific effect regarding emotional attention in this time interval. Regarding the time course of the effects, an influence of the HPA on these MEG correlates of attention seems less likely. An influence of cerebral catecholaminergic systems is plausible, but not definite.

  12. Neural correlates of stress- and food cue-induced food craving in obesity: association with insulin levels.

    Science.gov (United States)

    Jastreboff, Ania M; Sinha, Rajita; Lacadie, Cheryl; Small, Dana M; Sherwin, Robert S; Potenza, Marc N

    2013-02-01

    Obesity is associated with alterations in corticolimbic-striatal brain regions involved in food motivation and reward. Stress and the presence of food cues may each motivate eating and engage corticolimibic-striatal neurocircuitry. It is unknown how these factors interact to influence brain responses and whether these interactions are influenced by obesity, insulin levels, and insulin sensitivity. We hypothesized that obese individuals would show greater responses in corticolimbic-striatal neurocircuitry after exposure to stress and food cues and that brain activations would correlate with subjective food craving, insulin levels, and HOMA-IR. Fasting insulin levels were assessed in obese and lean subjects who were exposed to individualized stress and favorite-food cues during functional MRI. Obese, but not lean, individuals exhibited increased activation in striatal, insular, and hypothalamic regions during exposure to favorite-food and stress cues. In obese but not lean individuals, food craving, insulin, and HOMA-IR levels correlated positively with neural activity in corticolimbic-striatal brain regions during favorite-food and stress cues. The relationship between insulin resistance and food craving in obese individuals was mediated by activity in motivation-reward regions including the striatum, insula, and thalamus. These findings demonstrate that obese, but not lean, individuals exhibit increased corticolimbic-striatal activation in response to favorite-food and stress cues and that these brain responses mediate the relationship between HOMA-IR and food craving. Improving insulin sensitivity and in turn reducing corticolimbic-striatal reactivity to food cues and stress may diminish food craving and affect eating behavior in obesity.

  13. Non-invasive Imaging based Detection and Mapping of Brain Oxidative Stress and its Correlation with Cognitive Functions

    Science.gov (United States)

    2017-05-14

    the impact of oxidative stress on brain function, but also enable development of reliable screening tools for cognitive performance of individuals in...of Brain Oxidative Stress and its Correlation with Cognitive Functions Date 04/20/2017 PI information: Dr. Pravat K. Mandal,Ph.D Professor...relationship between the brain oxidative status and stress at a cellular, physiological as well as a psychological level. These stressors, in turn, have

  14. Perceived stress and bruxism in university students.

    Science.gov (United States)

    Cavallo, Pierpaolo; Carpinelli, Luna; Savarese, Giulia

    2016-12-21

    Many studies have shown the correlation between bruxism and stress that affects the quality of life of university students. The present study highlights this correlation-for the first time-in a group of university students in Italy. We have investigated the prevalence of awake and asleep bruxism and its correlation with perceived stress in a group of 278 Italian undergraduate students (117 M). A self report questionnaire was constructed using a socio-demographic test, the Perceived Stress Scale (PSS) and the item n. 8 of the Fonseca Questionnaire for presence of bruxism. The perceived stress score using PSS-10 scale was 32.2 (SD 4.6, 95% CL 31.6-32.7) for all the subjects, with significant gender difference: M = 31.2 and F = 32.9 (P = 0.0019). The prevalence for awake bruxism was 37.9% (F = 40.8%; M = 34.2%,), while for sleep bruxism was 31.8% (F = 33.3%; M = 29.1%), both without significant gender difference. A positive correlation, with significant concordance and dependence, between stress score and awake bruxism was present for male students only. University students showed higher bruxism and stress levels compared to the general population, with higher stress for females, but, even if female students show higher stress, a correlation between stress and bruxism exists only for male gender. Further studies should be performed.

  15. Depression, anxiety, stress and hyperemesis gravidarum: temporal and case controlled correlates.

    Directory of Open Access Journals (Sweden)

    Peng Chiong Tan

    Full Text Available OBJECTIVE: To evaluate the temporal and case-controlled correlations of anxiety, depression and stress with hyperemesis gravidarum. STUDY DESIGN: We performed a longitudinal cohort study of women with hyperemesis gravidarum using the Depression, Anxiety and Stress Scale (DASS-21 to evaluate psychological distress at hospitalization and in the third trimester of pregnancy (from 28 weeks gestation. Third pregnancy trimester controls were recruited from routine antenatal clinic attendees who were matched to gestational age at the second DASS-21 assessment in the HG cohort. RESULTS: The prevalences of nausea and vomiting, depression, anxiety and stress caseness in newly hospitalised hyperemesis gravidarum women were 100% and 100%, 19%, 69% and 21% which by the third trimester had fallen to 15.7% and 9.9%, 4%, 19% and 3% and in third trimester controls were 15.9% and 14.2%, 14%, 61% and 20% respectively. Within the hyperemesis gravidarum cohort, nausea, vomiting depression, anxiety and stress reduced significantly by an absolute 84.3% (95% CI 76.2%-89.8%, 90.1% (82.8%-94.2%, 14.9% (7.2%-23.0%, 49.6% (38.6%-58.7% and 18.2% (10.4%-26.4% respectively between hospitalization for hyperemesis gravidarum and at the third trimester. In the third trimester, when comparing the hyperemesis gravidarum cohort to controls, the risk of nausea or vomiting was similar but depression, anxiety and stress were significantly lower: adjusted odds ratio AOR 0.10 (95% CI 0.03-0.5, 0.11 (0.05-0.23 and 0.08 (0.02-0.33 respectively. CONCLUSION: Our study revealed a reassuring pattern of a strong rebound from depression, anxiety and stress in women with hyperemesis gravidarum such that by the third pregnancy trimester the level of psychological distress was even lower than in controls. This observation imply that much of the psychological distress in acute hyperemesis gravidarum is self-limiting and probably in the causal pathway of hyperemesis gravidarum. Care in women with

  16. Perceived stress correlates with visceral obesity and lipid parameters of the metabolic syndrome: A systematic review and meta-analysis.

    Science.gov (United States)

    Tenk, Judit; Mátrai, Péter; Hegyi, Péter; Rostás, Ildikó; Garami, András; Szabó, Imre; Hartmann, Petra; Pétervári, Erika; Czopf, László; Hussain, Alizadeh; Simon, Mária; Szujó, Szabina; Balaskó, Márta

    2018-05-12

    Perceived stress has been proposed as a risk factor of metabolic syndrome. However, correlations between perceived stress and parameters of the metabolic syndrome have not been properly analyzed despite extensive research data on the topic. Our current meta-analysis aimed to examine the mutual association between perceived stress of patients and parameters of metabolic syndrome. This systematic review has been registered on the PROSPERO database (registration number CRD42017055293). Eligible studies divided participants based on their stress level or on the presence of metabolic syndrome. They reported at least one parameter of the metabolic syndrome or the stress level of the participants measured with some stress scale. Data from 17 articles met the eligibility criteria and were included. Random effects model with the DerSimonian and Laird weighting methods was applied. I-squared indicator and Q test were performed to assess heterogeneity. Although the majority of individual studies failed to demonstrate correlations between stress and their analyzed parameters of metabolic syndrome, our meta-analysis showed a significant association between stress and BMI [average effect size (ES) with 95% confidence interval (95%CI), ES = 0.65, 95%CI 0.16, 1.14), waist circumference (ES = 1.84 cm, 95%CI 0.79, 2.89) and serum triglyceride level (ES = 7.52 mg/dl, 95%CI 0.07, 14.96). Additional analysis confirmed effects of stress on serum HDL (ES = - 1.699 mg/dl, 95%CI -2.966, -0.432) and diastolic blood pressure (ES = 1.04 mmHg, 95%CI 0.18, 1.89). No correlations were found for fasting glucose or systolic blood pressure. No association between metabolic syndrome and stress level of patients was detected either. The potentially key role of visceral obesity in the association between perceived stress and dyslipidemia or diastolic blood pressure are discussed together with potential moderators (e.g. gender-differences, variations in stress assessment and

  17. Stress field models from Maxwell stress functions: southern California

    Science.gov (United States)

    Bird, Peter

    2017-08-01

    shallow stress maxima and discontinuous horizontal compression at the Moho, which the new model can only approximate. The new model also lacks the spatial resolution to portray the localized stress states that may occur near the central surfaces of weak faults; instead, the model portrays the regional or background stress field which provides boundary conditions for weak faults. Peak shear stresses in one registered model and one alternate model are 120 and 150 MPa, respectively, while peak vertically integrated shear stresses are 2.9 × 1012 and 4.1 × 1012 N m-1. Channeling of deviatoric stress along the strong Great Valley and the western slope of the Peninsular Ranges is evident. In the neotectonics of southern California, it appears that deviatoric stress and long-term strain rate have a negative correlation, because regions of low heat flow are strong and act as stress guides, while undergoing very little internal deformation. In contrast, active faults lie preferentially in areas with higher heat flow, and their low strength keeps deviatoric stresses locally modest.

  18. On the stress-free lattice expansion of porous cordierite

    International Nuclear Information System (INIS)

    Bruno, Giovanni; Efremov, Alexander M.; Clausen, Bjorn; Balagurov, Anatoly M.; Simkin, Valeriy N.; Wheaton, Bryan R.; Webb, James E.; Brown, Donald W.

    2010-01-01

    An extensive investigation of the lattice expansion (up to 1200 deg. C) of porous synthetic cordierite (obtained by firing a mixture of talc, clay, alumina and silica) was carried out using time-of-flight neutron diffraction at LANSCE, Los Alamos, NM, USA and FNLP, Dubna, Russia. An extruded rod and several powders, with different particle size (dispersity), were studied, with the aim of monitoring the variation of the (lattice) micro-strain as a function of temperature and its influence on the microscopic and macroscopic thermal expansion. Results show a different expansion of the a- and b-axes of the orthorhombic cell (in the rod above 800 deg. C). While the finest powder seems to contract more along the c-axis, thus hinting at the presence of smaller stress, the integral peak width increases as a function of temperature in the intermediate range (300-700 deg. C). This could be explained by the integrity factor modeling in terms of micro-cracking. In polycrystalline cordierite, the model implies tension along the a- and b-axes (positive thermal expansion) accompanied by compression along the c-axis (negative thermal expansion) and a stress release upon cooling, via a thermal micro-cracking mechanism. The calculations of the cordierite macroscopic thermal expansion having as input crystal axial expansions assumed to be stress-free allowed us to conclude that even a fine powder (5 μm particle size) cannot be considered completely stress-free. This conclusion is supported by microstructural observations.

  19. Alteration of gene expression profile in Niemann-Pick type C mice correlates with tissue damage and oxidative stress.

    Directory of Open Access Journals (Sweden)

    Mary C Vázquez

    Full Text Available BACKGROUND: Niemann-Pick type C disease (NPC is a neurovisceral lipid storage disorder mainly characterized by unesterified cholesterol accumulation in lysosomal/late endosomal compartments, although there is also an important storage for several other kind of lipids. The main tissues affected by the disease are the liver and the cerebellum. Oxidative stress has been described in various NPC cells and tissues, such as liver and cerebellum. Although considerable alterations occur in the liver, the pathological mechanisms involved in hepatocyte damage and death have not been clearly defined. Here, we assessed hepatic tissue integrity, biochemical and oxidative stress parameters of wild-type control (Npc1(+/+; WT and homozygous-mutant (Npc1(-/-; NPC mice. In addition, the mRNA abundance of genes encoding proteins associated with oxidative stress, copper metabolism, fibrosis, inflammation and cholesterol metabolism were analyzed in livers and cerebella of WT and NPC mice. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed various oxidative stress parameters in the liver and hepatic and cerebellum gene expression in 7-week-old NPC1-deficient mice compared with control animals. We found signs of inflammation and fibrosis in NPC livers upon histological examination. These signs were correlated with increased levels of carbonylated proteins, diminished total glutathione content and significantly increased total copper levels in liver tissue. Finally, we analyzed liver and cerebellum gene expression patterns by qPCR and microarray assays. We found a correlation between fibrotic tissue and differential expression of hepatic as well as cerebellar genes associated with oxidative stress, fibrosis and inflammation in NPC mice. CONCLUSIONS/SIGNIFICANCE: In NPC mice, liver disease is characterized by an increase in fibrosis and in markers associated with oxidative stress. NPC is also correlated with altered gene expression, mainly of genes involved in oxidative stress

  20. Correlation among perceived stress, emotional intelligence, and burnout of resident doctors in a medical college of West Bengal: A mediation analysis.

    Science.gov (United States)

    Mitra, Satabdi; Sarkar, Aditya Prasad; Haldar, Dibakar; Saren, Asit Baren; Lo, Sourav; Sarkar, Gautam Narayan

    2018-01-01

    Perceived stress and burnout are by-products of powerless responsibility imposed on resident doctors. Emotional intelligence (EI) works as an adapting and coping tool. The objective of this study is to find out the role of work-related perceived stress on burnout and influence of EI on it. A descriptive cross-sectional study was conducted from February to April 2016 among 63 resident doctors of different departments of Bankura Sammilani Medical College and Hospital. Data were collected through a self-administered questionnaire for background characteristics and work-related variables. Cohen perceived stress scale, Trait EI, and Shirom-Melamed burnout questionnaire were applied for measuring perceived stress, EI, and burnout, respectively. Statistical analysis was done with of SPSS version 22.0, and for mediation analysis, Andrew F. Hyne's SPSS macro was adopted. Nonparametric bootstrapping was done assuming small sample. Out of complete responses, 67%, 22.9%, and 9.8% were from clinical, paraclinical, and preclinical specialties, respectively. Burnout had a significant positive correlation with perceived stress and in negative correlation with EI-well-being and positive correlation with EI-self-control and sociability. Physical fatigue factor of burnout had a significant positive correlation with EI-emotionality. Perceived stress had a negative correlation with EI-well-being. On mediation analysis, assuming EI as a mediator, total, direct, and indirect effects of perceived stress on burnout were significant (burnout by perceived stress among resident doctors. This necessitates more attention by decision-makers toward this burning problem for the sake of care of caregivers.

  1. Impact of chronic maternal stress during early gestation on maternal-fetal stress transfer and fetal stress sensitivity in sheep.

    Science.gov (United States)

    Dreiling, Michelle; Schiffner, Rene; Bischoff, Sabine; Rupprecht, Sven; Kroegel, Nasim; Schubert, Harald; Witte, Otto W; Schwab, Matthias; Rakers, Florian

    2018-01-01

    Acute stress-induced reduction of uterine blood flow (UBF) is an indirect mechanism of maternal-fetal stress transfer during late gestation. Effects of chronic psychosocial maternal stress (CMS) during early gestation, as may be experienced by many working women, on this stress signaling mechanism are unclear. We hypothesized that CMS in sheep during early gestation augments later acute stress-induced decreases of UBF, and aggravates the fetal hormonal, cardiovascular, and metabolic stress responses during later development. Six pregnant ewes underwent repeated isolation stress (CMS) between 30 and 100 days of gestation (dGA, term: 150 dGA) and seven pregnant ewes served as controls. At 110 dGA, ewes were chronically instrumented and underwent acute isolation stress. The acute stress decreased UBF by 19% in both the CMS and control groups (p stress-induced cortisol and norepinephrine concentrations indicating a hyperactive hypothalamus-pituitary-adrenal (HPA)-axis and sympathetic-adrenal-medullary system. Increased fetal norepinephrine is endogenous as maternal catecholamines do not cross the placenta. Cortisol in the control but not in the CMS fetuses was correlated with maternal cortisol blood concentrations; these findings indicate: (1) no increased maternal-fetal cortisol transfer with CMS, (2) cortisol production in CMS fetuses when the HPA-axis is normally inactive, due to early maturation of the fetal HPA-axis. CMS fetuses were better oxygenated, without shift towards acidosis compared to the controls, potentially reflecting adaptation to repeated stress. Hence, CMS enhances maternal-fetal stress transfer by prolonged reduction in UBF and increased fetal HPA responsiveness.

  2. Neural correlates of stress-induced and cue-induced drug craving: influences of sex and cocaine dependence.

    Science.gov (United States)

    Potenza, Marc N; Hong, Kwang-ik Adam; Lacadie, Cheryl M; Fulbright, Robert K; Tuit, Keri L; Sinha, Rajita

    2012-04-01

    Although stress and drug cue exposure each increase drug craving and contribute to relapse in cocaine dependence, no previous research has directly examined the neural correlates of stress-induced and drug cue-induced craving in cocaine-dependent women and men relative to comparison subjects. Functional MRI was used to assess responses to individualized scripts for stress, drug/alcohol cue and neutral-relaxing-imagery conditions in 30 abstinent cocaine-dependent individuals (16 women, 14 men) and 36 healthy recreational-drinking comparison subjects (18 women, 18 men). Significant three-way interactions between diagnostic group, sex, and script condition were observed in multiple brain regions including the striatum, insula, and anterior and posterior cingulate. Within women, group-by-condition interactions were observed involving these regions and were attributable to relatively increased regional activations in cocaine-dependent women during the stress and, to a lesser extent, neutral-relaxing conditions. Within men, group main effects were observed involving these same regions, with cocaine-dependent men demonstrating relatively increased activation across conditions, with the main contributions from the drug and neutral-relaxing conditions. In men and women, subjective drug-induced craving measures correlated positively with corticostriatal-limbic activations. In cocaine dependence, corticostriatal-limbic hyperactivity appears to be linked to stress cues in women, drug cues in men, and neutral-relaxing conditions in both. These findings suggest that sex should be taken into account in the selection of therapies in the treatment of addiction, particularly those targeting stress reduction.

  3. [Evaluation methods in the work/stress correlations in law enforcement].

    Science.gov (United States)

    Magnavital, Nicola; Garbarino, Sergio; Siegrist, Johannes

    2014-01-01

    Stress in police: assessment methods. Police work is unanimously considered stressful. Prevention of stress in police is of the utmost importance, as a distressed officer could be hazardous for third parties. There is scientific evidence that the relationship between occupational stressors and their psychological and physical consequences can be described by Karasek's demand-control-support (DCS) model and the effort / reward imbalance (ERI) model of Siegrist. This study summarizes the results of surveys conducted using the DCS and ERI questionnaires.on police officers from the VI Mobile Unit of Genoa who were engaged in public order management at the G8 summit in L'Aquila in 2009. In spite of the high alert due to expected threats to public order during the G8 meeting, police officers were not affected by "distress". When the policemen were compared to other categories of workers, their stress levels were in the lowest range. In most cases, the personality profile of these workers did not differ substantially from that of the general population. There was an association between personality and stress response. The levels of perceived stress were significantly associated with absence from work. The prevalence of mental disorders in police officers was significantly lower than that of the general population. Occupational stress was associated with indicators of depression, anxiety and burnout. The DCS and ERI models yielded complementary results and proved to be effective in assessing the effects of stress in law enforcement. The extent of perceived stress does not directly depend on external events, but on the way in which these are handled: routine work may be more stressful than a single critical event. Special police forces are particularly resilient to stress, partly due to the characteristics and personality of individual officers, but mainly on account of their training. Occupational stress is associated with a lower level of psychological well-being and an

  4. Ambulatory stress monitoring with a wearable bluetooth electrocardiographic device.

    Science.gov (United States)

    Hong, Sungyoup; Yang, Youngmo; Lee, Jangyoung; Yang, Heebum; Park, Kyungnam; Lee, Suyeul; Lee, Inbum; Jang, Yongwon

    2010-01-01

    We tried to monitor stress by using a wearable one channel ECG device that can send ECG signals through Bluetooth wireless communication. Noxious physical and mental arithmetic stress was given three times repeatedly to healthy adults, and cortisol and catecholamines were measured serially from peripheral blood. At the same time, time domain and frequency domain parameters of heart rate variability (HRV) were calculated by taking precordial electrocardiogram. The intensity of correlation between subjective visual analogue scale (VAS) and catecholamine, cortisol, and HRV parameters according to stress was analyzed by using concordance correlation coefficients. The HRV triangular index and LF/HF ratio had high concordance correlation with the degree of stress in the physical stress model. In mental arithmetic stress model, the HRV triangular index and LF/HF ratio had weak concordance correlation with the degree of stress, and it had lower predictability than epinephrine. In both models, cortisol had some correlation with catecholamine, but it had little correlation with HRV parameters. HRV parameters using wearable one channel ECG device can be useful in predicting acute stress and also in many other areas.

  5. Correlation between passive film-induced stress and stress corrosion cracking of α-Ti in a methanol solution at various potentials

    International Nuclear Information System (INIS)

    Guo, X.Z.; Gao, K.W.; Chu, W.Y.; Qiao, L.J.

    2003-01-01

    The flow stress of a specimen of α-Ti before unloading is different with the yield stress of the same specimen after unloading and forming a passive film through immersing in a methanol solution at various constant potentials. The difference is the passive film-induced stress. The film-induced stress and susceptibility to stress corrosion cracking (SCC) in the methanol solution at various potentials were measured. At the stable open-circuit potential and under anodic polarization, both film-induced tensile stress σ p and susceptibility to SCC had a maximum value. The film-induced stress and SCC susceptibility, however, decreased steeply with a decrease in potential under cathodic polarization. When the potential V≤-280 mV SCE , the film-induced stress became compressive; correspondingly, susceptibility to SCC was zero. Therefore, the variation of film-induced stress with potential was consistent with that of susceptibility to SCC. A large film-induced tensile stress is the necessary condition for SCC of α-Ti in the methanol solution. The symbol and amount of the film-induced stress were related to the compositions of the passive film, which have been analyzed using the X-ray photoelectron spectrum (XPS)

  6. Mechanical characteristics of fully mechanized top-coal caving face and surrounding rock stress shell

    Energy Technology Data Exchange (ETDEWEB)

    Xie Guang-xiang [Anhui University of Science and Technology, Huainan (China)

    2005-06-15

    The distribution of surrounding rock stress in fully mechanized top-coal caving (FMTC) face was fully researched by large-scale and non-linear three-dimensional numerical simulation and equivalent laboratory. The results show that, there is the structure that is made of macroscopical stress shell composed of high stress binds in overlying strata of FMTC face. Stress shell, which bears and pass load of overlying strata, is primary supporting body. The stress in skewback of stress shell forms abutment pressure of surrounding rock in vicinity of working face. Bond-beam structure lies in reducing zone under stress shell. It only bear partial burden of strata under stress shell. The uppermost mechanical characteristic of FMTC face is lying in the low stress area under stress shell. It is the essential cause of strata behaviors of FMTC face relaxation. On the basis of analyzing stress shell, the mechanical essence that top coal performs a function of bedding is demonstrated. 4 refs., 7 figs.

  7. Self-similar drag reduction in plug-flow of suspensions of macroscopic fibers

    NARCIS (Netherlands)

    Gillissen, J.J.J.; Hoving, J.P.

    2012-01-01

    Pipe flow experiments show that turbulent drag reduction in plug-flow of concentrated suspensions of macroscopic fibers is a self-similar function of the wall shear stress over the fiber network yield stress. We model the experimental observations, by assuming a central fiber network plug, whose

  8. Correlation of Stress Concentration Factors for T-Welded Connections – Finite Element Simulations and Fatigue Behavior

    Directory of Open Access Journals (Sweden)

    Gerardo Terán Méndez

    Full Text Available Abstract The stress concentration factors (SCFs in welded connections usually occur at zones with high stress levels. Stress concentrations reduce the fatigue behavior of welded connections in offshore structures and cracking can develop. By using the grinding technique, cracking can be eliminated. Stress concentration factors are defined as a ratio of maximum stress at the intersection to nominal stress on the brace. Defining the stress concentration factor is an important stage in the fatigue behavior of welded connections. Several approaches have evolved for designing structures with the classical S-N approach for estimating total life. This work correlates to the stress concentration factors of T-welded connections and the fatigue behavior. Stress concentration factors were computed with the finite element employing 3D T-welded connections with intact and grinding depth conditions. Then, T-welded connections were constructed with A36 plate steel and welded with E6013 electrodes to obtain the stress-life (S-N approach. The methodology from previous works was used to compute the SCF and fabricate the T-welded connections. The results indicated that the grinding process could restore the fatigue life of the T-welded connections for SCFs values in the range of 1.29. This value can be considered to be a low SCF value in T-welded connection. However, for higher SCF values, the fatigue life decreased, compromising and reducing the structural integrity of the T-welded connections.

  9. Correlates and predictors of parenting stress among internationally adopting mothers: A longitudinal investigation.

    Science.gov (United States)

    Viana, Andres G; Welsh, Janet A

    2010-07-01

    This study examined correlates and predictors of parenting stress among internationally adopting (IA) mothers with the goal of expanding the knowledge base on the experiences of adoptive parents. One hundred and forty-three IA mothers completed pre-adoption (Time 0) and six months post-adoption (Time 1) surveys with questions regarding child-, parent-, and family-related characteristics. Mother reports of higher depression symptoms, higher expectations of child developmental and behavioral/emotional problems, and a greater number of children in the family at pre-adoption were significantly related to higher parenting stress six months post-adoption. In contrast, mother reports of higher expectations for child acceptance and higher perceived social support at pre-adoption were significantly related to lower parenting stress six months post-adoption. Higher maternal depression symptoms, higher expectations of child behavior/emotional problems, and a greater number of children in the family at pre-adoption together accounted for 22% of the variance in parenting stress six months post-adoption. Concurrent higher maternal depression symptoms and higher reports of child behavioral/emotional problems predicted higher parenting stress six months post-adoption over and above pre-adoption predictors, and accounted for an additional 33% of the variance. Results and directions for future research are discussed from a transactional perspective, with particular emphasis on the importance of pre-adoptive information for adoption research and practice.

  10. PREVALENCE AND CORRELATES OF JOB STRESS AMONG JUNIOR DOCTORS IN THE UNIVERSITY COLLEGE HOSPITAL, IBADAN.

    Science.gov (United States)

    Adeolu, J O; Yussuf, O B; Popoola, O A

    2016-12-01

    Doctors respond differently to their complex work environment, some find it stimulating while others find it stressful. This study aimed to assess the prevalence and correlates of stress among junior doctors in a teaching hospital in Southwest Nigeria. A descriptive cross sectional survey of all junior doctors employed at the University College Hospital, Ibadan was carried out. Information was collected with a structured pretested questionnaire from 253 doctors. Descriptive statistics were generated. T-test, chi square and logistic regression analyses were conducted using SPSS version 16. Statistical significance was set at 5%. Mean age of respondents was 29.9 (±4.1) years, 61.3% were males, 59% had spent less than 5 years in medical practice, and 34.8% were married. Majority (79.4%) were resident doctors. Prevalence of stress, job dissatisfaction and poor mental health were 31.6%, 15.4% and 9.9% respectively. Age, gender, years of medical practice, religion, ethnicity and marital status were not significantly associated with job stress (p>0.05). Doctors who were stressed were more likely to be dissatisfied with their jobs (OR=2.33; CI=1.08-4.04) and to have poor mental health (OR=3.82; CI=1.47-9.95) than those who were not stressed. The prevalence of stress in this study is high, and job dissatisfaction and poor mental health have been implicated as determinants of stress. As such, there should be an improvement in doctors' welfare, health care facilities and delivery.

  11. Perceived Stress, Its Physiological Correlates, and Quality of Life in Patients With Irritable Bowel Syndrome.

    Science.gov (United States)

    Weaver, Kristen R; Melkus, Gail D'Eramo; Fletcher, Jason; Henderson, Wendy A

    2018-05-01

    Irritable bowel syndrome (IBS) is a chronic, common disorder of the gastrointestinal tract associated with high psychological comorbidity and diminished quality of life. Patients with IBS display a heightened sensitivity to stress, although the literature is inconsistent as to whether they have a dysregulated stress response. The purpose of the present investigation, a substudy of a larger research effort, was to examine physiological correlates of perceived stress in patients with IBS (cortisol and adrenocorticotropic hormone) and to explore associations between perceived stress and quality of life. A total of 101 participants (35 with IBS [predominant subtypes IBS-constipation and IBS-diarrhea] and 66 healthy controls [HCs]) completed self-report inventories regarding perceived stress and quality of life, and fasting peripheral blood was drawn. Participants with IBS did not differ from the HC in demographic or physiological measures but did differ in psychological measures, reporting significantly higher levels of perceived stress and lower levels of quality of life. Perceived stress and quality of life were not significantly associated in IBS participants. However, differential findings of the stress response were found within IBS participants by sex, race, and subtype. These findings illustrate the heterogeneity of the IBS patient population, underscore the necessity of evaluating larger sample sizes and increasing the diversity of such samples to include males and ethnic minorities, and demonstrate the importance of taking an individualized approach to evaluation and treatment in the IBS patient population.

  12. Correlates of Stress and Coping among Jordanian Nursing Students during Clinical Practice in Psychiatric/Mental Health Course.

    Science.gov (United States)

    Alzayyat, Abdulkarim; Al-Gamal, Ekhlas

    2016-10-01

    Training in psychiatric settings is stressful for nursing students. The purpose of this study was to examine the correlations between the students' characteristics, their stress degrees, stressors and types of coping strategies they experience during training in psychiatric course. A descriptive, correlational, longitudinal design was used. Sixty-five undergraduate nursing students were recruited randomly from five Jordanian universities. Self-report questionnaires were administered at the second semester of the 2012-2013 academic year. The findings showed that students who utilized avoidance or transference strategies reported high stress degrees. Moreover, the results showed that those students who were in the fourth year, with a low family income, who avoid extracurricular activities, with a low academic grade or who registered in other clinical course(s) reported high stress degrees. These findings present a worthy data for the clinical instructors that facilitate students training in psychiatric settings and promote their psychosocial well-being. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Psychological stress-relieving effects of chewing - Relationship between masticatory function-related factors and stress-relieving effects.

    Science.gov (United States)

    Tasaka, Akinori; Kikuchi, Manaki; Nakanishi, Kousuke; Ueda, Takayuki; Yamashita, Shuichiro; Sakurai, Kaoru

    2018-01-01

    The objective of the present study was to investigate the relationship between masticatory function-related factors (masticatory performance, occlusal contact area, maximum bite force, number of chewing strokes, and muscle activity) and the stress-relieving effects of chewing. A total of 28 healthy male subjects were instructed to rest or chew for 10min after 30min of stress loading with arithmetic calculations. Their stress state was assessed by measuring salivary cortisol levels. Saliva was collected at three time points: before stress loading, immediately after stress loading, and 10min after stress loading. Compared to resting, chewing produced a significantly greater reduction in the rate of change in salivary cortisol levels 10min after stress loading. A negative correlation was observed between the rate of decrease in salivary cortisol levels and the number of chewing strokes. No significant correlation was observed between the rate of decrease in salivary cortisol levels and other measurement items. In healthy dentulous people, the number of chewing strokes has been shown to be a masticatory function-related factor that affects stress relief from chewing, suggesting the possibility that more appropriate chewing would produce a greater effect psychological stress relief. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  14. Perceived life stress exposure modulates reward-related medial prefrontal cortex responses to acute stress in depression.

    Science.gov (United States)

    Kumar, Poornima; Slavich, George M; Berghorst, Lisa H; Treadway, Michael T; Brooks, Nancy H; Dutra, Sunny J; Greve, Douglas N; O'Donovan, Aoife; Bleil, Maria E; Maninger, Nicole; Pizzagalli, Diego A

    2015-07-15

    Major depressive disorder (MDD) is often precipitated by life stress and growing evidence suggests that stress-induced alterations in reward processing may contribute to such risk. However, no human imaging studies have examined how recent life stress exposure modulates the neural systems that underlie reward processing in depressed and healthy individuals. In this proof-of-concept study, 12 MDD and 10 psychiatrically healthy individuals were interviewed using the Life Events and Difficulties Schedule (LEDS) to assess their perceived levels of recent acute and chronic life stress exposure. Additionally, each participant performed a monetary incentive delay task under baseline (no-stress) and stress (social-evaluative) conditions during functional MRI. Across groups, medial prefrontal cortex (mPFC) activation to reward feedback was greater during acute stress versus no-stress conditions in individuals with greater perceived stressor severity. Under acute stress, depressed individuals showed a positive correlation between perceived stressor severity levels and reward-related mPFC activation (r=0.79, p=0.004), whereas no effect was found in healthy controls. Moreover, for depressed (but not healthy) individuals, the correlations between the stress (r=0.79) and no-stress (r=-0.48) conditions were significantly different. Finally, relative to controls, depressed participants showed significantly reduced mPFC gray matter, but functional findings remained robust while accounting for structural differences. Small sample size, which warrants replication. Depressed individuals experiencing greater recent life stress recruited the mPFC more under stress when processing rewards. Our results represent an initial step toward elucidating mechanisms underlying stress sensitization and recurrence in depression. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Financial stress spillovers in advanced economies

    NARCIS (Netherlands)

    Apostolakis, G.; Papadopoulos, A.

    2014-01-01

    Financial stress co-movements are positively associated with crisis periods. Dynamic conditional correlations increase during periods of high uncertainty. The US is the dominant transmitter of financial stress spillovers. The total stress spillover index explains 19.9% of the forecast error

  16. [Compassion as a mediator between stressful events and perceived stress in Greek students].

    Science.gov (United States)

    Tholouli, E; Maridaki-Kassotaki, A; Varvogli, L; Chrousos, G P

    2016-01-01

    Compassion is closely related with human's survival as a mammal and has been developed through evolution for pain reduction, for forming affiliative bonds and alliances with non kin in order to increase protection and cope with external threats. Compassion seems to influence people's ability to deal with life's adverse situations such as stress and it is linked with lower psychopathology and greater wellbeing. Compassion is closely related to empathy and altruism and it is defined as the recognition of the pain of the self or others' that is accompanied with the will to take action in order to relieve the person from pain. Its main features are kindness instead of self-judgment and indifference, the recognition of common humanity instead of the feeling of separation and mindfulness when facing adverse conditions instead of over-identification with one's pain or disengagement with the pain of others. According to the biopsychosocial approach, stress can be defined by three dimensions such as the cause or stressful factors that can be major life events or daily hassles, the perception of stress that is manifested through cognitive, emotional and behavioural reactions and the physiological response for achieving homeostasis. The purpose of the present study was to investigate the role of compassion for self and others in the occurrence of stressful events and levels of perceived stress in students. Participants were 280 undergraduate students from two Greek universities. Results indicated that students who had experienced a greater amount of stressful events during the past year reported having higher levels of perceived stress and that higher self-compassion was correlated with less perceived stress. Moreover, the adverse effect of stressful events on perceived stress was partially explained by the mediating role of self-compassion. Students who reported more stressful events showed higher compassion for others in opposition to compassion towards themselves but

  17. Opposite Effects of Stress on Pain Modulation Depend on the Magnitude of Individual Stress Response.

    Science.gov (United States)

    Geva, Nirit; Defrin, Ruth

    2018-04-01

    The effect of acute stress on pain threshold and intolerance threshold are reported as producing either hypoalgesia or hyperalgesia. Yet, the contribution of individual stress reactivity in this respect has not been established. The aim was to test 2 pain modulation paradigms under acute stress manipulation, to our knowledge, for the first time, to study whether stress differentially affects pain modulation, and whether the effect is related to individual stress response. Participants were 31 healthy subjects. Conditioned pain modulation (CPM) and pain adaptation were measured before and after inducing an acute stress response using the Montreal Imaging Stress Task. Subjects' stress response was evaluated according to salivary cortisol, autonomic function, and perceived stress and anxiety. The Montreal Imaging Stress Task induced a validated stress response. On a group level, stress induced reduction in CPM magnitude and increase in pain adaptation compared with baseline. These responses correlated with stress reactivity. When the group was subdivided according to stress reactivity, only high stress responders exhibited reduced CPM whereas only low stress responders exhibited increased pain adaptation. The results suggest that acute stress may induce opposite effects on pain modulation, depending on individual stress reactivity magnitude, with an advantage to low stress responders. This study evaluated the effect of acute stress on pain modulation. Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders. Identification of high stress responders may promote better pain management. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

  18. Micromechanical modelling of the cyclic stress-strain behaviour of nickel polycrystals

    International Nuclear Information System (INIS)

    Steckmeyer, A.; Sauzay, M.; Weidner, A.; Hieckmann, E.

    2012-01-01

    A crystalline elasto-plasticity model is proposed to describe the cyclic behaviour of face-centred cubic crystals. It is based on many experimental observations correlating the observed dislocation structures with the orientations of corresponding crystals. The model distinguishes between two families of crystals. The first family gathers crystals for which the tension-compression loading axis is located in the centre of the standard stereo-graphic triangle. These crystals, in which bundle and/or slip band dislocation structures are usually observed, are subjected to single slip deformation. The second family gathers crystals in which labyrinths or wall dislocation structures develop. These crystals are subjected to multiple slip deformation. Crystalline plasticity parameters are adjusted using only the single crystal cyclic stress strain curves measured for one orientation of each of the two families. The relevance of the model is evaluated through finite elements calculations of the uniaxial cyclic deformation of texture-free nickel polycrystals at room temperature. The macroscopic predictions are in reasonable agreement with experimental data concerning both the cyclic stress-strain curve and the hysteresis loops provided either large grain sizes or intermediate to high plastic strains are considered. By construction, the modelling is unable to predict grain size effect observed at low plastic strain. The distributions of the mean grain plastic strains become narrower as the macroscopic plastic strain amplitude increases, which appears consistent with the large scattering in high-cycle fatigue lifetimes usually observed. On the contrary, the distributions of mean grain axial stresses get broader, in agreement with neutron and X-ray diffraction measurement values published in the literature. The influence of the material parameters is then discussed. Finally, the cumulative probability curves of the number of cycles to fatigue microcrack nucleation are deduced

  19. Residual stresses in zircaloy welds

    International Nuclear Information System (INIS)

    Santisteban, J. R.; Fernandez, L; Vizcaino, P.; Banchik, A.D.; Samper, R; Martinez, R. L; Almer, J; Motta, A.T.; Colas, K.B; Kerr, M.; Daymond, M.R

    2009-01-01

    Welds in Zirconium-based alloys are susceptible to hydrogen embrittlement, as H enters the material due to dissociation of water. The yield strain for hydride cracking has a complex dependence on H concentration, stress state and texture. The large thermal gradients produced by the applied heat; drastically changes the texture of the material in the heat affected zone, enhancing the susceptibility to delayed hydride cracking. Normally hydrides tend to form as platelets that are parallel to the normal direction, but when welding plates, hydride platelets may form on cooling with their planes parallel to the weld and through the thickness of the plates. If, in addition to this there are significant tensile stresses, the susceptibility of the heat affected zone to delayed hydride cracking will be increased. Here we have measured the macroscopic and microscopic residual stressed that appear after PLASMA welding of two 6mm thick Zircaloy-4 plates. The measurements were based on neutron and synchrotron diffraction experiments performed at the Isis Facility, UK, and at Advanced Photon Source, USA, respectively. The experiments allowed assessing the effect of a post-weld heat treatment consisting of a steady increase in temperature from room temperature to 450oC over a period of 4.5 hours; followed by cooling with an equivalent cooling rate. Peak tensile stresses of (175± 10) MPa along the longitudinal direction were found in the as-welded specimen, which were moderately reduced to (150±10) MPa after the heat-treatment. The parent material showed intergranular stresses of (56±4) MPa, which disappeared on entering the heat-affected zone. In-situ experiments during themal cyclong of the material showed that these intergranular stresses result from the anisotropy of the thermal expansion coefficient of the hexagonal crystal lattice. [es

  20. Endogenous ROS levels in C. elegans under exogenous stress support revision of oxidative stress theory of life-history tradeoffs.

    Science.gov (United States)

    Smith, Samson W; Latta, Leigh C; Denver, Dee R; Estes, Suzanne

    2014-07-24

    The oxidative stress theory of life-history tradeoffs states that oxidative stress caused by damaging free radicals directly underpins tradeoffs between reproduction and longevity by altering the allocation of energetic resources between these tasks. We test this theory by characterizing the effects of exogenous oxidative insult and its interaction with thermal stress and diet quality on a suite of life-history traits and correlations in Caenorhabditis elegans nematodes. We also quantify demographic aging rates and endogenous reactive oxygen species (ROS) levels in live animals. Our findings indicate a tradeoff between investment in reproduction and antioxidant defense (somatic maintenance) consistent with theoretical predictions, but correlations between standard life-history traits yield little evidence that oxidative stress generates strict tradeoffs. Increasing oxidative insult, however, shows a strong tendency to uncouple positive phenotypic correlations and, in particular, to reduce the correlation between reproduction and lifespan. We also found that mild oxidative insult results in lower levels of endogenous ROS accompanied by hormetic changes in lifespan, demographic aging, and reproduction that disappear in combined-stress treatments--consistent with the oxidative stress theory of aging. Our findings demonstrate that oxidative stress is a direct contributor to life-history trait variation and that traditional tradeoffs are not necessary to invoke oxidative stress as a mediator of relationships between life-history traits, supporting previous calls for revisions to theory.

  1. Correlates of cortisol in human hair: implications for epidemiologic studies on health effects of chronic stress.

    Science.gov (United States)

    Wosu, Adaeze C; Valdimarsdóttir, Unnur; Shields, Alexandra E; Williams, David R; Williams, Michelle A

    2013-12-01

    Assessment of cortisol concentrations in hair is one of the latest innovations for measuring long-term cortisol exposure. We performed a systematic review of correlates of cortisol in human hair to inform the design, analysis, and interpretation of future epidemiologic studies. Relevant publications were identified through electronic searches on PubMed, WorldCat, and Web of Science using keywords, "cortisol," "hair," "confounders," "chronic," "stress," and "correlates." Thirty-nine studies were included in this review. Notwithstanding scarce data and some inconsistencies, investigators have found hair cortisol concentrations to be associated with stress-related psychiatric symptoms and disorders (e.g., post-traumatic stress disorder), medical conditions indicating chronic activation of the hypothalamic-pituitary-adrenal axis (e.g., Cushing's syndrome), and other life situations associated with elevated risk of chronic stress (e.g., shiftwork). Results from some studies suggest that physical activity, adiposity, and substance abuse may be correlates of hair cortisol concentrations. In contrast to measures of short-term cortisol release (saliva, blood, and urine), cigarette smoking and use of oral contraceptives appear not to be associated with hair cortisol concentrations. Studies of pregnant women indicate increased hair cortisol concentrations across successive trimesters. The study of hair cortisol presents a unique opportunity to assess chronic alterations in cortisol concentrations in epidemiologic studies. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Correlations among Stress Parameters, Meat and Carcass Quality Parameters in Pigs

    Science.gov (United States)

    Dokmanovic, Marija; Baltic, Milan Z.; Duric, Jelena; Ivanovic, Jelena; Popovic, Ljuba; Todorovic, Milica; Markovic, Radmila; Pantic, Srdan

    2015-01-01

    Relationships among different stress parameters (lairage time and blood level of lactate and cortisol), meat quality parameters (initial and ultimate pH value, temperature, drip loss, sensory and instrumental colour, marbling) and carcass quality parameters (degree of rigor mortis and skin damages, hot carcass weight, carcass fat thickness, meatiness) were determined in pigs (n = 100) using Pearson correlations. After longer lairage, blood lactate (prigor mortis (p<0.05), suggesting that lactate could be a predictor of both meat quality and the level of preslaughter stress. Cortisol affected carcass quality, so higher levels of cortisol were associated with increased hot carcass weight, carcass fat thickness on the back and at the sacrum and marbling, but also with decreased meatiness. The most important meat quality parameters (pH and temperature after 60 minutes) deteriorated when blood lactate concentration was above 12 mmol/L. PMID:25656214

  3. Stress transmission in soil

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    We urgently need increased quantitative knowledge on stress transmission in real soils loaded with agricultural machinery. 3D measurements of vertical stresses under tracked wheels were performed in situ in a Stagnic Luvisol (clay content 20 %) continuously cropped with small grain cereals......). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil in each of three depths (0.3, 0.6 and 0.9 m), covering the width of the wheeled area. The position of the wheel relative to the transducers was recorded using a laser sensor. Finally, the vertical stresses near...... the soil-tyre interface were measured in separate tests by 17 stress transducers across the width of the tyres. The results showed that the inflation pressure controlled the level of maximum stresses at 0.3 m depth, while the wheel load was correlated to the measured stresses at 0.9 m depth. This supports...

  4. Micro-stress dominant displacive reconstructive transition in lithium aluminate

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Qiwei; Yan, Xiaozhi; Zhang, Leilei; Peng, Fang [Institute of Atomic and Molecular Physics, Sichuan University, 610065 Chengdu (China); Lei, Li, E-mail: lei@scu.edu.cn; He, Duanwei [Institute of Atomic and Molecular Physics, Sichuan University, 610065 Chengdu (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, 610065 Chengdu (China); Li, Xiaodong [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2016-08-15

    It is supposed that diffusive reconstructive transitions usually take place under hydrostatic pressure or low stresses, and displacive reconstructive phase transitions easily occur at nonhydrostatic pressure. Here, by in-situ high pressure synchrotron X-ray diffraction and single-crystal Raman scattering studies on lithium aluminate at room temperature, we show that the reconstructive transition mechanism is dependent on the internal microscopic stresses rather than the macroscopic stresses. In this case, even hydrostatic pressure can favor the displacive transition if the compressibility of crystal is anisotropic. During hydrostatic compression, γ-LiAlO{sub 2} transforms to δ-LiAlO{sub 2} at about 4 GPa, which is much lower than that in previous nonhydrostatic experiments (above 9 GPa). In the region where both phases coexist, there are enormous microscopic stresses stemming from the lattice mismatch, suggesting that this transition is displacive. Furthermore, the atomic picture is drawn with the help of the shear Raman modes.

  5. Subacute stress and chronic stress interact to decrease intestinal barrier function in rats.

    Science.gov (United States)

    Lauffer, Adriana; Vanuytsel, Tim; Vanormelingen, Christophe; Vanheel, Hanne; Salim Rasoel, Shadea; Tóth, Joran; Tack, Jan; Fornari, Fernando; Farré, Ricard

    2016-01-01

    Psychological stress increases intestinal permeability, potentially leading to low-grade inflammation and symptoms in functional gastrointestinal disorders. We assessed the effect of subacute, chronic and combined stress on intestinal barrier function and mast cell density. Male Wistar rats were allocated to four experimental groups (n = 8/group): 1/sham; 2/subacute stress (isolation and limited movement for 24 h); 3/chronic crowding stress for 14 days and 4/combined subacute and chronic stress. Jejunum and colon were collected to measure: transepithelial electrical resistance (TEER; a measure of epithelial barrier function); gene expression of tight junction molecules; mast cell density. Plasma corticosterone concentration was increased in all three stress conditions versus sham, with highest concentrations in the combined stress condition. TEER in the jejunum was decreased in all stress conditions, but was significantly lower in the combined stress condition than in the other groups. TEER in the jejunum correlated negatively with corticosterone concentration. Increased expression of claudin 1, 5 and 8, occludin and zonula occludens 1 mRNAs was detected after subacute stress in the jejunum. In contrast, colonic TEER was decreased only after combined stress, and the expression of tight junction molecules was unaltered. Increased mast cell density was observed in the chronic and combined stress condition in the colon only. In conclusion, our data show that chronic stress sensitizes the gastrointestinal tract to the effects of subacute stress on intestinal barrier function; different underlying cellular and molecular alterations are indicated in the small intestine versus the colon.

  6. Stress Relaxation Effects in TiNi SMA During Superelastic Deformation: Experiment and Constitutive Model

    Science.gov (United States)

    Pieczyska, Elżbieta A.; Kowalewski, Zbigniew L.; Dunić, Vladimir Lj.

    2017-12-01

    This paper presents an investigation of thermomechanical effects related to the phenomena of stress relaxation occurring in TiNi SMA subjected to modified program of displacement-controlled tension. The deformation data were taken from testing machine, whereas the temperature changes accompanying the exothermic/endothermic martensite forward/reverse transformation were measured by infrared camera. At the advanced stages of the transformations, the strain was kept constant for a few minutes and the SMA load and temperature were recorded continuously. As a consequence, the stress and temperature changed significantly during the loading stops. A large stress drop, caused by the transformation, was observed during the relaxation stage in both courses of the SMA loading and unloading. Moreover, the non-uniform temperature distribution, reflecting macroscopically inhomogeneous transformation, lapsed while the strain was kept constant, yet restarted at the end of the relaxation stop and developed at the reloading stage. Along with the experimental results, the mechanical and thermal responses induced by the transformation were obtained by 3D coupled thermomechanical numerical analysis, realized in partitioned approach. Latent heat production was correlated with an amount of the martensitic volume fraction. The stress and temperature drops recorded during the experiment were satisfactorily reproduced by the model proposed for the SMA thermomechanical coupling.

  7. Fecal pellet output does not always correlate with colonic transit in response to restraint stress and corticotropin-releasing factor in rats

    International Nuclear Information System (INIS)

    Nakade, Yukiomi; Mantyh, C.; Pappas, T.N.; Takahashi, Toku

    2007-01-01

    Fecal pellet output has been assessed as a colonic motor activity because of its simplicity. However, it remains unclear whether an acceleration of colonic transit correlates well with an increase in fecal pellet output. We examined the causal relationship between colonic transit and fecal pellet output stimulated by the central application of corticotropin-releasing factor (CRF) and restraint stress. Immediately after intracisternal injection of CRF, 51 Cr was injected via a catheter positioned in the proximal colon. Ninety minutes after 51 Cr injection, the total number of excreted feces was counted, and then the rats were killed. The radioactivity of each colonic segment was evaluated, and the geometric center (GC) of the distribution of 51 Cr was calculated. For the restraint stress study, after administration of 51 Cr into the proximal colon, rats were submitted to wrapping restraint stress for 90 min. Then they were killed, and GC was calculated. Both restraint stress and CRF significantly accelerated colonic transit. There was a positive correlation observed between fecal pellet output and GC of colonic transit in response to restraint stress, but not CRF, when the number of excreted feces was more than three. In contrast, there was no significant correlation observed between the two in stress and CRF when the number of excreted feces was less than two. The acceleration of colonic transit in response to restraint stress and central administration of CRF does not always correlate with an increase in fecal pellet output. (author)

  8. Level of occupational stress of court probation officers and style of coping with stress

    Directory of Open Access Journals (Sweden)

    Łukasz Wirkus

    2015-08-01

    Full Text Available Background The relationship between a court probation officer and their ward is a specific one and is frequently connected with enormous individuals costs. This fact is connected with the character of the job, and with the conditions determining its character. Psychosocial threats may influence both mental and somatic health, directly or indirectly, by means of the influence exerted by stress. Participants and procedure The main study was conducted at the offices of the teams of the Court Probation Service. The teams of the Court Probation Service are part of the structure of the following 9, randomly selected, district courts (DCs: DC Wrocław, DC Bydgoszcz, DC Szczecin, DC Poznań, DC Łódź, DC Lublin, DC Kraków, DC Katowice and DC Białystok. Participation in the research was voluntary and anonymous; the tools were arranged in sets, and the sequence of those sets was random. The sets of research tools were received by 1,000 individuals altogether. Results The conducted research confirmed the need to verify the significance of the feeling of occupational stress of court probation officers at the workplace and the correlations between it and a number of variables. Below, I present statistical analyses concerning various aspects of occupational stress experienced in the studied group, including correlations between the general level of occupational stress and the dimensions of it, and organizational predictors. The objective of the research was to indicate the styles of coping with stress and the correlations of them with the stress felt by court probation officers. Conclusions The research confirms a significant influence exerted by organizational determinants upon the general level of felt occupational stress. Professional court probation officers experience a higher level of felt occupational stress; what is conducive to that is high encumbrance with occupational responsibilities, and also functioning directly in structures of the court of

  9. Standard test method for determining the effective elastic parameter for X-ray diffraction measurements of residual stress

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1998-01-01

    1.1 This test method covers a procedure for experimentally determining the effective elastic parameter, Eeff, for the evaluation of residual and applied stresses by X-ray diffraction techniques. The effective elastic parameter relates macroscopic stress to the strain measured in a particular crystallographic direction in polycrystalline samples. Eeff should not be confused with E, the modulus of elasticity. Rather, it is nominally equivalent to E/(1 + ν) for the particular crystallographic direction, where ν is Poisson's ratio. The effective elastic parameter is influenced by elastic anisotropy and preferred orientation of the sample material. 1.2 This test method is applicable to all X-ray diffraction instruments intended for measurements of macroscopic residual stress that use measurements of the positions of the diffraction peaks in the high back-reflection region to determine changes in lattice spacing. 1.3 This test method is applicable to all X-ray diffraction techniques for residual stress measurem...

  10. Non-destructive measurement of residual stresses in U-0.8 wt.% Ti by neutron diffraction

    International Nuclear Information System (INIS)

    Salinas-Rodriguez, A.; Root, J.H.; Holden, T.M.; Macewen, S.R.; Ludtka, G.M.

    1990-01-01

    The macroscopic residual stress distribution in γ-quenched and stress levelled U-0.8wt% Ti alloy tubes was studied using neutron diffraction techniques. Residual strains were evaluated from the difference in d-spacings measured in the tubes and in small reference samples machined from each tube. Residual stresses were calculated with the isotropic bulk value of the elastic constraints for polycrystalline α-U. Quenching from the γ field resulted in a nearly equi-biaxial stress state at every point across the wall thickness of the tube. The magnitude of the radial stress was very small compared with that of the axial and hoop stresses which were compressive at the surfaces and tensile in the interior. Stress levelling relieved almost completely the hoop residual stress without affecting the radial stress. The axial residual stress becomes tensile through the wall thickness and remains constant at about 20% of its magnitude in the as-quenched condition

  11. The behavior of Kevlar fibers under environmental-stress conditions

    Science.gov (United States)

    Perry, Mark Charles

    There are a myriad of mechanisms by which polymers can degrade and fail. It is therefore important to understand the physical mechanics, chemistry, their interactions, and kinetics. This pursuit becomes more than just "academic" because these mechanisms might just change with service conditions (i.e. environment and loading). If one does not understand these processes from the molecular to macroscopic scale it would be exceedingly difficult to gain information from accelerated testing because the mechanisms just might change from one condition to another. The purpose of this study was to probe these processes on scales ranging from molecular to macroscopic in environmental stress conditions. This study reports the results of environmental-stress degradation of Kevlar 49 fibers. The environmental agent of focus was the ubiquitous air pollutant complex NOsb{x}. Other materials and environments were investigated to a lesser extent for purposes of comparison. Mechanical property (i.e., short-term strength, modulus, and creep lifetime) degradation was examined using single fiber, yarn, and epoxy coated yarn (composite) specimens under environmental-stress conditions. Optical and scanning electron microscopes were employed to examine and compare the appearance of fracture features resulting from the various testing conditions. Atomic force microscopy augmented these studies with detailed topographical mappings and measures of the fracture surface frictional and modulus properties. Molecular processes (i.e., chain scission and other mechanical-chemical reactions) were probed by measures of changes in viscosity average molecular weight and the infrared spectra. It was demonstrated that environmental-stress degradation effects do occur in the Kevlar-NOsb{x} gas system. Strength decay in environmentally exposed unloaded fibers was demonstrated and a synergistic response in creep reduced fiber lifetimes by three orders of magnitude at moderate loadings. That is to say, the

  12. Stress Management: Job Stress

    Science.gov (United States)

    Healthy Lifestyle Stress management Job stress can be all-consuming — but it doesn't have to be. Address your triggers, keep perspective and ... stress triggers, it's often helpful to improve time management skills — especially if you tend to feel overwhelmed ...

  13. Stress tensor correlators of CCFT{sub 2} using flat-space holography

    Energy Technology Data Exchange (ETDEWEB)

    Asadi, Mohammad; Baghchesaraei, Omid; Fareghbal, Reza [Shahid Beheshti University, Department of Physics, Tehran (Iran, Islamic Republic of)

    2017-11-15

    We use the correspondence between three-dimensional asymptotically flat spacetimes and two-dimensional contracted conformal field theories (CCFTs) to derive the stress tensor correlators of CCFT{sub 2}. On the gravity side we use the metric formulation instead of the Chern-Simons formulation of three-dimensional gravity. This method can also be used for the four-dimensional case, where there is no Chern-Simons formulation for the bulk theory. (orig.)

  14. The correlation between mechanical stress and magnetic anisotropy in ultrathin films

    International Nuclear Information System (INIS)

    Sander, D.

    1999-01-01

    The impact of stress-driven structural transitions and of film strain on the magnetic properties of nm ferromagnetic films is discussed. The stress-induced bending of film-substrate composites is analysed to derive information on film stress due to lattice mismatch or due to surface-stress effects. The magneto-elastic coupling in epitaxial films is determined directly from the magnetostrictive bending of the substrate. The combination of stress measurements with magnetic investigations by the magneto-optical Kerr effect (MOKE) reveals the modification of the magnetic anisotropy by film stress. Stress-strain relations are derived for various epitaxial orientations to facilitate the analysis of the substrate curvature. Biaxial film stress and magneto-elastic coupling coefficients are measured in epitaxial Fe films in situ on W single-crystal substrates. Tremendous film stress of more than 10 GPa is measured in pseudomorphic Fe layers, and the important role of film stress as a driving force for the formation of misfit distortions and for inducing changes of the growth mode in monolayer thin films is presented. The direct measurement of the magneto-elastic coupling in epitaxial films proves that the magnitude and sign of the magneto-elastic coupling deviate from the respective bulk value. Even a small film strain of order 0.1% is found to induce a significant change of the effective magneto-elastic coupling coefficient. This peculiar behaviour is ascribed to a second-order strain dependence of the magneto-elastic energy density, in contrast to the linear strain dependence that is valid for bulk samples. (author)

  15. Bidirectional crosstalk between stress-induced gastric ulcer and depression under chronic stress.

    Directory of Open Access Journals (Sweden)

    Shuang Zhang

    Full Text Available Stress contributes to a variety of diseases and disorders such as depression and peptic ulcer. The present study aimed to investigate the correlation between stress ulcer and depression in pathogenesis and treatment by using chronic stress depression (CSD, chronic psychological stress ulcer (CPSU and water immersion restrain stress models in rats. Our data showed that the ulcer index of the animals after CSD exposure was significantly higher than that of controls. Depression-like behaviors were observed in rat after CPSU exposure. Fluoxetine hydrochloride significantly reduced the ulcer index of rats exposed to CPSU stress, while ranitidine inhibited depression-like behavior of the animals in CSD group. The ulcer index of rats administered with mifepristone after CPSU stress was markedly reduced compared to CPSU group, although there was no significant difference in the depression-like behavior between mifepristone-treated CSD group and naive controls. We also found that the rats exposed to CPSU or CSD stress displayed a lower level of corticosterone than naive controls, however, the acute stress (AS group showed an opposite result. Additionally, in order to study the relevance of H(2 receptors and depression, we treated the CSD group with cimetidine and famotidine respectively. The data showed that cimetidine inhibited depression-like behavior in CSD rats, and famotidine had no impact on depression. Overall our data suggested that the hypothalamic-pituitary-adrenal (HPA axis dysfunction may be the key role in triggering depression and stress ulcer. Acid-suppressing drugs and antidepressants could be used for treatment of depression and stress ulcer respectively. The occurrence of depression might be inhibited by blocking the central H(2 receptors.

  16. Specific features of the determination of residual stresses in materials by diffraction techniques

    Science.gov (United States)

    Gorkunov, E. S.; Zadvorkin, S. M.; Goruleva, L. S.

    2017-12-01

    Residual stresses arising in separate machine parts and structural components during production and use to a large extent govern their lifetime. In this connection, the development and improvement of nondestructive methods for the determination of residual stresses is an important task for nondestructive testing. Standards regulate only the determination of macroscopic stresses, and in practice these stresses are most often determined with the application of the sin2ψ method. This paper, using quenched structural steels as an example, compares the results of residual stress determination by the sin2ψ method with those obtained by the method based on the analysis of the diffraction line profile as dependent on the value of the irradiated volume. It is demonstrated that, as the irradiated volume decreases, the value of residual stresses determined by the sin2ψ method may vary considerably, up to the change of the sign. For a more complete characteristic of residual stresses it is proposed to use, besides the determination of macrostresses by the shift of the diffraction lines, the value of microscopic stresses calculated from the line profile analysis.

  17. Peri-implant stress correlates with bone and cement morphology: Micro-FE modeling of implanted cadaveric glenoids.

    Science.gov (United States)

    Wee, Hwabok; Armstrong, April D; Flint, Wesley W; Kunselman, Allen R; Lewis, Gregory S

    2015-11-01

    Aseptic loosening of cemented joint replacements is a complex biological and mechanical process, and remains a clinical concern especially in patients with poor bone quality. Utilizing high resolution finite element analysis of a series of implanted cadaver glenoids, the objective of this study was to quantify relationships between construct morphology and resulting mechanical stresses in cement and trabeculae. Eight glenoid cadavers were implanted with a cemented central peg implant. Specimens were imaged by micro-CT, and subject-specific finite element models were developed. Bone volume fraction, glenoid width, implant-cortex distance, cement volume, cement-cortex contact, and cement-bone interface area were measured. Axial loading was applied to the implant of each model and stress distributions were characterized. Correlation analysis was completed across all specimens for pairs of morphological and mechanical variables. The amount of trabecular bone with high stress was strongly negatively correlated with both cement volume and contact between the cement and cortex (r = -0.85 and -0.84, p implant-cortex distance. Contact between the cement and underlying cortex may dramatically reduce trabecular bone stresses surrounding the cement, and this contact depends on bone shape, cement amount, and implant positioning. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Habitual Coffee Consumption Does Not Correlate with Blood Pressure, Inflammation and Endothelial Dysfunction but Partially Correlates with Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Erizal Sugiono

    2013-04-01

    Full Text Available BACKGROUND: Coffee is the most widely consumed beverage in the world and has been known to have effects on cardiovascular system. Many researchers have examined the effects of coffee consumption on blood pressure (BP and risk of cardiovascular disease (CVD, but their results were inconsistent and still remain a subject of controversy. Oxidative stress, inflammation, and endothelial dysfunction have been known as risk factors of hypertension and CVD. Those factors are also known to be affected by coffee consumption. The aim of this study was to examine the relationship between the effects of habitual coffee consumption on BP and to examine the role of oxidative stress (F2 isoprostane, inflammation (high sensitive C-reactive protein (hsCRP and endothelial dysfunction (asymmetric dimethylarginine (ADMA. METHODS: This was a cross-sectional study in which 47 healthy, non-smoking men aged 30-60 years with varying coffee-drinking habits were enrolled. BP and blood/urine analysis of biomarkers were measured in the morning before activity. Coffee consumption was assessed using a questionnaire. The differences among variables were analyzed using ANOVA and the correlations between variables were analyzed using Kendall’s Tau correlation analysis. RESULTS: Habitual coffee consumption did not correlate with systolic/diastolic BP (r=-0.02; p=0.856 and r=0.15; p=0.230, respectively. Concentrations of ADMA and hsCRP were also not correlated with coffee consumption (r=0.03; p=0.764 and r=0.04; p=0.701, respectively. Coffee consumption only showed significant correlation with F2 isoprostane (r=0.34; p=0.004. CONCLUSIONS: BP was not affected by coffee consumption although coffee consumption has a significant correlation with F2 isoprostane. These findings suggest that correlation between coffee consumption and BP might be explained by other factors that were not included in this study. KEYWORDS: coffee, caffeine, cardiovascular disease, blood pressure, oxidative

  19. The Big Five personality and temperamental traits and its correlation with styles of coping with stress in the fire brigade officers

    Directory of Open Access Journals (Sweden)

    Justyna Szrajda

    2017-09-01

    Full Text Available Selecting specific professional activities (e.g. a brigade officer and methods for coping with difficult situations may result from personal predispositions of a given person. Personality is founded on the innate temperament. The way of dealing with stress depends on personality traits whose influence is manifested, amongst other things, in the selection of specific coping styles. The current study aim to examine the level of correlation between personality and temperamental traits with manifested coping styles. The study covered 58 volunteers – male fire brigade officers. The following tools were used: Personality Inventory, NEO-FFI, Formal Characteristics of Behaviour: Temperament Inventory – Revised Version, FCZ-KT (R and Coping Inventory for Stressful Situations, CISS. Emotion-focused coping style for stressful situations correlates with the following traits: positively, with perseveration (r=0.5115 and with emotional reactivity (r=0.4927, and negatively, with briskness (r=-0.3926 and endurance (r=-0.5408. The task-oriented coping style for stressful situations correlates positively with extraversion (r=0.3236 and conscientiousness (r=0.3088, and negatively with neuroticism (r=-0.3368 in the NEO-FFI. The emotion-focused coping style for stressful situations is positively correlated with neuroticism (NEO-FFI (r=0.4150. In fire brigade officers, As far as personality traits were concerned, fire brigade officers scored relatively high in extraversion, conscientiousness and low in neuroticism and were likely to demonstrate the task-oriented coping style for stressful situations. Lower level of perseveration and high level of briskness and endurance were associated with emotion-focused coping style for stressful situations. Similarly, the tendency to focus on emotions experienced in stressful situations were associated with high level of neuroticism in the study group.

  20. Correlation between hierarchical structure of crystal networks and macroscopic performance of mesoscopic soft materials and engineering principles.

    Science.gov (United States)

    Lin, Naibo; Liu, Xiang Yang

    2015-11-07

    This review examines how the concepts and ideas of crystallization can be extended further and applied to the field of mesoscopic soft materials. It concerns the structural characteristics vs. the macroscopic performance, and the formation mechanism of crystal networks. Although this subject can be discussed in a broad sense across the area of mesoscopic soft materials, our main focus is on supramolecular materials, spider and silkworm silks, and biominerals. First, the occurrence of a hierarchical structure, i.e. crystal network and domain network structures, will facilitate the formation kinetics of mesoscopic phases and boost up the macroscopic performance of materials in some cases (i.e. spider silk fibres). Second, the structure and performance of materials can be correlated in some way by the four factors: topology, correlation length, symmetry/ordering, and strength of association of crystal networks. Moreover, four different kinetic paths of crystal network formation are identified, namely, one-step process of assembly, two-step process of assembly, mixed mode of assembly and foreign molecule mediated assembly. Based on the basic mechanisms of crystal nucleation and growth, the formation of crystal networks, such as crystallographic mismatch (or noncrystallographic) branching (tip branching and fibre side branching) and fibre/polymeric side merging, are reviewed. This facilitates the rational design and construction of crystal networks in supramolecular materials. In this context, the (re-)construction of a hierarchical crystal network structure can be implemented by thermal, precipitate, chemical, and sonication stimuli. As another important class of soft materials, the unusual mechanical performance of spider and silkworm silk fibres are reviewed in comparison with the regenerated silk protein derivatives. It follows that the considerably larger breaking stress and unusual breaking strain of spider silk fibres vs. silkworm silk fibres can be interpreted

  1. Investigation of Macroscopic Brittle Creep Failure Caused by Microcrack Growth Under Step Loading and Unloading in Rocks

    Science.gov (United States)

    Li, Xiaozhao; Shao, Zhushan

    2016-07-01

    The growth of subcritical cracks plays an important role in the creep of brittle rock. The stress path has a great influence on creep properties. A micromechanics-based model is presented to study the effect of the stress path on creep properties. The microcrack model of Ashby and Sammis, Charles' Law, and a new micro-macro relation are employed in our model. This new micro-macro relation is proposed by using the correlation between the micromechanical and macroscopic definition of damage. A stress path function is also introduced by the relationship between stress and time. Theoretical expressions of the stress-strain relationship and creep behavior are derived. The effects of confining pressure on the stress-strain relationship are studied. Crack initiation stress and peak stress are achieved under different confining pressures. The applied constant stress that could cause creep behavior is predicted. Creep properties are studied under the step loading of axial stress or the unloading of confining pressure. Rationality of the micromechanics-based model is verified by the experimental results of Jinping marble. Furthermore, the effects of model parameters and the unloading rate of confining pressure on creep behavior are analyzed. The coupling effect of step axial stress and confining pressure on creep failure is also discussed. The results provide implications on the deformation behavior and time-delayed rockburst mechanism caused by microcrack growth on surrounding rocks during deep underground excavations.

  2. Determination of global and local residual stresses in SOFC by X-ray diffraction

    International Nuclear Information System (INIS)

    Villanova, Julie; Sicardy, Olivier; Fortunier, Roland; Micha, Jean-Sebastien; Bleuet, Pierre

    2010-01-01

    Solid Oxide Fuel Cell (SOFC) is a high-performance electrochemical device for energy conversion. A single cell is composed of five layers made of different ceramic materials: anode support, anode functional layer, electrolyte, cathode functional layer and cathode. The mechanical integrity of the cell is a major issue during its lifetime, especially for the electrolyte layer. Damage of the cells is mainly due to the high operating temperature, the 'redox' behaviour of the anode and the brittleness of the involved materials. Since residual stresses are known to play a significant role in the damage evolution, it is important to determine them. For this purpose, residual stresses in an anode-supported planar SOFC were measured by X-ray diffraction. Firstly, macroscopic stresses in each phase of each layer were studied using the sin 2 ψ method on a laboratory X-ray goniometer at room temperature. This technique enables the calculation of residual stress of the material from the measurement of the crystal lattice deformation. The electrolyte has been found under bi-axial compressive stress of -920 MPa. Secondly, X-ray measurements controlling depth penetration were made in the electrolyte using grazing incidence method. The results show that the stress is not homogenous in the layer. The first five micrometers of the electrolyte have been found less constrained (-750 MPa) than the complete layer, suggesting a gradient of deformation in the electrolyte from the interface with the Anode Functional Layer to the free surface. Finally, local stress measurements were made on the electrolyte layer by X-ray synchrotron radiation that allows high accuracy measurement on the (sub-) micrometer scale. Polychromatic and monochromatic beams are used to determine the complete strain tensor from grain to grain in the electrolyte. First results confirm the macroscopic stress trend of the electrolyte. These X-ray techniques at different scales will contribute to a better understanding

  3. Environmental and Intrinsic Correlates of Stress in Free-Ranging Wolves.

    Directory of Open Access Journals (Sweden)

    Barbara Molnar

    Full Text Available When confronted with a stressor, animals react with several physiological and behavioral responses. Although sustained or repeated stress can result in severe deleterious physiological effects, the causes of stress in free-ranging animals are yet poorly documented. In our study, we aimed at identifying the main factors affecting stress levels in free-ranging wolves (Canis lupus.We used fecal cortisol metabolites (FCM as an index of stress, after validating the method for its application in wolves. We analyzed a total of 450 fecal samples from eleven wolf packs belonging to three protected populations, in Italy (Abruzzo, France (Mercantour, and the United States (Yellowstone. We collected samples during two consecutive winters in each study area. We found no relationship between FCM concentrations and age, sex or social status of individuals. At the group level, our results suggest that breeding pair permanency and the loss of pack members through processes different from dispersal may importantly impact stress levels in wolves. We measured higher FCM levels in comparatively small packs living in sympatry with a population of free-ranging dogs. Lastly, our results indicate that FCM concentrations are associated with endoparasitic infections of individuals.In social mammals sharing strong bonds among group members, the death of one or several members of the group most likely induces important stress in the remainder of the social unit. The potential impact of social and territorial stability on stress levels should be further investigated in free-ranging populations, especially in highly social and in territorial species. As persistent or repeated stressors may facilitate or induce pathologies and physiological alterations that can affect survival and fitness, we advocate considering the potential impact of anthropogenic causes of stress in management and conservation programs regarding wolves and other wildlife.

  4. Environmental and Intrinsic Correlates of Stress in Free-Ranging Wolves.

    Science.gov (United States)

    Molnar, Barbara; Fattebert, Julien; Palme, Rupert; Ciucci, Paolo; Betschart, Bruno; Smith, Douglas W; Diehl, Peter-Allan

    2015-01-01

    When confronted with a stressor, animals react with several physiological and behavioral responses. Although sustained or repeated stress can result in severe deleterious physiological effects, the causes of stress in free-ranging animals are yet poorly documented. In our study, we aimed at identifying the main factors affecting stress levels in free-ranging wolves (Canis lupus). We used fecal cortisol metabolites (FCM) as an index of stress, after validating the method for its application in wolves. We analyzed a total of 450 fecal samples from eleven wolf packs belonging to three protected populations, in Italy (Abruzzo), France (Mercantour), and the United States (Yellowstone). We collected samples during two consecutive winters in each study area. We found no relationship between FCM concentrations and age, sex or social status of individuals. At the group level, our results suggest that breeding pair permanency and the loss of pack members through processes different from dispersal may importantly impact stress levels in wolves. We measured higher FCM levels in comparatively small packs living in sympatry with a population of free-ranging dogs. Lastly, our results indicate that FCM concentrations are associated with endoparasitic infections of individuals. In social mammals sharing strong bonds among group members, the death of one or several members of the group most likely induces important stress in the remainder of the social unit. The potential impact of social and territorial stability on stress levels should be further investigated in free-ranging populations, especially in highly social and in territorial species. As persistent or repeated stressors may facilitate or induce pathologies and physiological alterations that can affect survival and fitness, we advocate considering the potential impact of anthropogenic causes of stress in management and conservation programs regarding wolves and other wildlife.

  5. Molecular correlates of impaired prefrontal plasticity in response to chronic stress

    NARCIS (Netherlands)

    Kuipers, SD; Trentani, A; Den Boer, JA; Ter Horst, GJ

    Disturbed adaptations at the molecular and cellular levels following stress could represent compromised neural plasticity that contributes to the pathophysiology of stress-induced disorders. Evidence illustrates atrophy and cell death of stress-vulnerable neurones in the prefrontal cortex. Reduced

  6. Stress 'deafness' in a language with fixed word stress: an ERP study on Polish

    Directory of Open Access Journals (Sweden)

    Ulrike eDomahs

    2012-11-01

    Full Text Available The aim of the present contribution was to examine the factors influencing the prosodic processing in a language with predictable word stress. For Polish, a language with fixed penultimate stress but several well-defined exceptions, difficulties in the processing and representation of prosodic information have been reported (e.g., Peperkamp & Dupoux, 2002. The present study utilized event-related potentials (ERPs to investigate the factors influencing prosodic processing in Polish. These factors are i the predictability of stress and ii the prosodic structure in terms of metrical feet. Polish native speakers were presented with correctly and incorrectly stressed Polish words and instructed to judge the correctness of the perceived stress patterns. For each stress violation an early negativity was found which was interpreted as reflection of an error-detection mechanism, and in addition exceptional stress patterns (= antepenultimate stress and post-lexical (= initial stress evoked a task-related positivity effect (P300 whose amplitude and latency is correlated with the degree of anomaly and deviation from an expectation. Violations involving the default (= penultimate stress in contrast did not produce such an effect. This asymmetrical result is interpreted to reflect that Polish native speakers are less sensitive to the default pattern than to the exceptional or post-lexical patterns. Behavioral results are orthogonal to the electrophysiological results showing that Polish speakers had difficulties to reject any kind of stress violation. Thus, on a meta-linguistic level Polish speakers appeared to be stress-‘deaf’ for any kind of stress manipulation, whereas the neural reactions differentiate between the default and lexicalized patterns.

  7. Remote sensing of drought and salinity stressed turfgrass

    Science.gov (United States)

    Ikemura, Yoshiaki

    The ability to detect early signs of stress in turfgrass stands using a rapid, inexpensive, and nondestructive method would be a valuable management tool. Studies were conducted to determine if digital image analysis and spectroradiometric readings obtained from drought- and salinity-stressed turfgrasses accurately reflected the varying degrees of stress and correlated strongly with visual ratings, relative water content (RWC) and leaf osmolality, standard methods for measuring stress in plants. Greenhouse drought and salinity experiments were conducted on hybrid bluegrass [Poa arachnifera (Torn.) x pratensis (L.)] cv. Reveille and bermudagrass [Cynodon dactylon (L.)] cv. Princess 77. Increasing drought and salinity stress led to decreased RWC, increased leaf osmolality, and decreased visual ratings for both species. Percent green cover and hue values obtained from digital image analysis, and Normalized Difference Vegetation Index (NDVI), calculated from spectroradiometric readings, were moderately to highly correlated with visual ratings, RWC, and leaf osmolality. Similarly, in a field validation study conducted on hybrid bluegrass, spectral reflectance ratios were moderately to highly correlated with visual ratings. In addition, percent green cover obtained from digital image analysis was strongly correlated with most of the spectral ratios, particularly the ratio of fluorescence peaks (r = -0.88 to -0.99), modified triangular vegetation index (MTVI) (r = 0.82 to 0.98), and NDVI (r = 0.84 to 0.99), suggesting that spectral reflectance and digital image analysis are equally effective at detecting changes in color brought on by stress. The two methods differed in their ability to distinguish between drought salinity stress. Hue values obtained from digital image analysis responded differently to increasing drought stress than to increasing salinity stress. Whereas the onset of drought stress was reflected by increased hue values followed by a decrease in values as

  8. Effect of intergranular stress on yielding of 316H during room temperature cyclic loading

    International Nuclear Information System (INIS)

    Al Mamun, Abdullah; Moat, Richard; Bouchard, John; Kelleher, Joe

    2016-01-01

    Assessment of cyclic deformation is an integral part of nuclear power plant life assessment code, as many of the components in plant go through scheduled and unscheduled cyclic deformation owing to varying thermal and mechanical stresses. In polycrystalline material like 316H, a type of micro stress known as intergranular stress is generated due to elastic and plastic anisotropies during such cyclic loading. In tension-compression loading cycles, these stresses remain in the material as a residual stress upon unloading to zero stress from the tensile/compressive peak or intermediates stresses. The magnitude of these stresses vary depending on the point in the cycle from which it was unloaded from. When the material is re-loaded either in the same or reverse loading direction these residual stresses increase or decrease the effective stress acting in the material and as such the macroscopic yield stress of the material in subsequent cycle is changed significantly. The magnitude of intergranular stresses in many differently oriented grain families can be measured simultaneously using time of flight (ToF) neutron diffraction technique. In this paper, we have used this technique to experimentally study, how these intergranular stresses affect the yield (proof) stress of 316H at room temperature. (author)

  9. Correlation of oxidative stress in patients with HBV-induced liver disease with HBV genotypes and drug resistance mutations.

    Science.gov (United States)

    Xianyu, Jianbo; Feng, Jiafu; Yang, Yuwei; Tang, Jie; Xie, Gang; Fan, Lingying

    2018-05-01

    This study aims to explore the correlation of oxidative stress (OxS) in patients with chronic hepatitis B (CHB) and the disease severity with HBV genotypes and drug resistance mutations. A total of 296 patients with CHB were enrolled into the study. PCR-reverse dot-blot hybridization was used to detect the HBV genotypes (B, C, and D) and the drug resistance-causing HBV mutant genes. In addition, the total oxidative stress (TOS) and total antioxidant status (TAS) were determined, and oxidative stress index (OSI) was calculated and compared. Serum levels of TOS and OSI, the B/C ratio, and drug resistance mutation rate were increased along with the elevated disease severity degree (CHBHBV mutation had higher serum TOS and OSI levels, while lower serum TAS levels (P HBV-induced liver disease, and the damage degree is correlated with the HBV genotype and drug resistance mutation. Oxidative stress might be a useful indicator of the progression of HBV-induced liver disease in patients. Copyright © 2018. Published by Elsevier Inc.

  10. Good stress, bad stress and oxidative stress: insights from anticipatory cortisol reactivity.

    Science.gov (United States)

    Aschbacher, Kirstin; O'Donovan, Aoife; Wolkowitz, Owen M; Dhabhar, Firdaus S; Su, Yali; Epel, Elissa

    2013-09-01

    Chronic psychological stress appears to accelerate biological aging, and oxidative damage is an important potential mediator of this process. However, the mechanisms by which psychological stress promotes oxidative damage are poorly understood. This study investigates the theory that cortisol increases in response to an acutely stressful event have the potential to either enhance or undermine psychobiological resilience to oxidative damage, depending on the body's prior exposure to chronic psychological stress. In order to achieve a range of chronic stress exposure, forty-eight post-menopausal women were recruited in a case-control design that matched women caring for spouses with dementia (a chronic stress model) with similarly aged control women whose spouses were healthy. Participants completed a questionnaire assessing perceived stress over the previous month and provided fasting blood. Three markers of oxidative damage were assessed: 8-iso-prostaglandin F(2α) (IsoP), lipid peroxidation, 8-hydroxyguanosine (8-oxoG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), reflecting oxidative damage to RNA/DNA respectively. Within approximately one week, participants completed a standardized acute laboratory stress task while salivary cortisol responses were measured. The increase from 0 to 30 min was defined as "peak" cortisol reactivity, while the increase from 0 to 15 min was defined as "anticipatory" cortisol reactivity, representing a cortisol response that began while preparing for the stress task. Women under chronic stress had higher 8-oxoG, oxidative damage to RNA (pstress and elevated oxidative stress damage, but only among women under chronic stress. Consistent with this model, bootstrapped path analysis found significant indirect paths from perceived stress to 8-oxoG and IsoP (but not 8-OHdG) via anticipatory cortisol reactivity, showing the expected relations among chronically stressed participants (p≤.01) Intriguingly, among those with low chronic stress

  11. Effects of a high mean stress on the high cycle fatigue life of PWA 1480 and correlation of data by linear elastic fracture mechanics

    Science.gov (United States)

    Majumdar, S.; Kwasny, R.

    1985-01-01

    High-cycle fatigue tests using 5-mm-diameter smooth specimens were performed on the single crystal alloy PWA 1480 (001 axis) at 70F (room temperature) in air and at 100F (538C) in vacuum (10 to the -6 power torr). Tests were conducted at zero mean stress as well as at high tensile mean stress. The results indicate that, although a tensile mean stress, in general, reduces life, the reduction in fatigue strength, for a given mean stress at a life of one million cycles, is much less than what is predicted by the usual linear Goodman plot. Further, the material appears to be significantly more resistant to mean stress effects at 1000F than at 70F. Metallographic examinations of failed specimens indicate that failures in all cases are initiated from micropores of sizes of the order of 30 to 40 microns. Since the macroscopic stress-strain response in all cases was observed to be linear elastic, linear elastic fracture mechanics (LEFM) analyses were carried out to determine the crack growth curves of the material assuming that crack initiation from a micropore (a sub o = 40 microns) occurs very early in life. The results indicate that the calculated crack growth rates at an R (defined as the ratio between minimum stress to maximum stress) value of zero are approximately the same at 70F as at 1000F. However, the calculated crack growth rates at other R ratios, both positive and negative, tend to be higher at 70F than at 1000F. Calculated threshold effects at large R values tend to be independent of temperature in the temperature regime studied. They are relatively constant with increasing R ratio up to a value of about 0.6, beyond which the calculated threshold stress intensity factor range decreases rapidly with increasing R ratios.

  12. [Effect of occupational stress on neurotransmitters in petroleum workers].

    Science.gov (United States)

    Jiang, Yu; Lian, Yulong; Tao, Ning; Ge, Hua; Liu, Jiwen

    2015-09-01

    To explore the effects of occupational stress on neurotransmitters in petroleum workers. 178 petroleum workers with the length of service ≥ 1 year were recruited to the subjects by the questionnaire of OSI-R. The levels of 5-hydroxy tryptamine (5-HT), norepinephrine (NE), neuropeptide Y (NPY) and substance P (SP) in serum were measured. The subjects were classified into 3 groups according to the scores of occupational stress. The levels of 5-HT NE and SP for over 15 working years were higher than those of less than 15 years (P occupational stress degree groups, multiple comparison showed high. occupational stress group was higher than those of low occupational stress group. Multivariate correlation analysis showed that the occupational stress and sleep quality component scores correlated positively with the 5-HT, NE and SP (P Occupational stress in petroleum workers is correlated with serum monoamine and neuropeptides neurotransmitters, and it may affect serum levels of monoamine and neuropeptides neurotransmitters.

  13. Correlates and Predictors of Parenting Stress among Internationally Adopting Mothers: A Longitudinal Investigation

    Science.gov (United States)

    Viana, Andres G.; Welsh, Janet A.

    2010-01-01

    This study examined correlates and predictors of parenting stress among internationally adopting (IA) mothers with the goal of expanding the knowledge base on the experiences of adoptive parents. One hundred and forty-three IA mothers completed pre-adoption (Time 0) and six months post-adoption (Time 1) surveys with questions regarding child-,…

  14. Residual stresses and fatigue in a duplex stainless steel

    International Nuclear Information System (INIS)

    Johansson, Johan

    1999-01-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  15. Residual stresses and fatigue in a duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Johan

    1999-05-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  16. Increased activity of osteocyte autophagy in ovariectomized rats and its correlation with oxidative stress status and bone loss

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuehua, E-mail: yuesjtu@126.com; Zheng, Xinfeng, E-mail: zxf272@126.com; Li, Bo, E-mail: libo@126.com; Jiang, Shengdan, E-mail: jiangsd@126.com; Jiang, Leisheng, E-mail: leisheng_jiang@126.com

    2014-08-15

    Highlights: • Examine autophagy level in the proximal tibia of ovariectomized rats. • Investigate whether autophagy level is associated with bone loss. • Investigate whether autophagy level is associated with oxidative stress status. - Abstract: Objectives: The objectives of the present study were to investigate ovariectomy on autophagy level in the bone and to examine whether autophagy level is associated with bone loss and oxidative stress status. Methods: 36 female Sprague–Dawley rats were randomly divided into sham-operated (Sham), and ovariectomized (OVX) rats treated either with vehicle or 17-β-estradiol. At the end of the six-week treatment, bone mineral density (BMD) and bone micro-architecture in proximal tibias were assessed by micro-CT. Serum 17β-estradiol (E2) level were measured. Total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity, catalase (CAT) activity in proximal tibia was also determined. The osteocyte autophagy in proximal tibias was detected respectively by Transmission Electron Microscopy (TEM), immunofluorescent histochemistry (IH), realtime-PCR and Western blot. In addition, the spearman correlation between bone mass, oxidative stress status, serum E2 and autophagy were analyzed. Results: Ovariectomy increased Atg5, LC3, and Beclin1 mRNA and proteins expressions while decreased p62 expression. Ovariectomy also declined the activities of T-AOC, CAT, and SOD. Treatment with E2 prevented the reduction in bone mass as well as restored the autophagy level. Furthermore, LC3-II expression was inversely correlated with T-AOC, CAT, and SOD activities. A significant inverse correlation between LC3-II expression and BV/TV, Tb.N, BMD in proximal tibias was found. Conclusions: Ovariectomy induced oxidative stress, autophagy and bone loss. Autophagy of osteocyte was inversely correlated with oxidative stress status and bone loss.

  17. Hydroxyurea-Induced Replication Stress

    Directory of Open Access Journals (Sweden)

    Kenza Lahkim Bennani-Belhaj

    2010-01-01

    Full Text Available Bloom's syndrome (BS displays one of the strongest known correlations between chromosomal instability and a high risk of cancer at an early age. BS cells combine a reduced average fork velocity with constitutive endogenous replication stress. However, the response of BS cells to replication stress induced by hydroxyurea (HU, which strongly slows the progression of replication forks, remains unclear due to publication of conflicting results. Using two different cellular models of BS, we showed that BLM deficiency is not associated with sensitivity to HU, in terms of clonogenic survival, DSB generation, and SCE induction. We suggest that surviving BLM-deficient cells are selected on the basis of their ability to deal with an endogenous replication stress induced by replication fork slowing, resulting in insensitivity to HU-induced replication stress.

  18. Thermodynamical inequivalence of quantum stress-energy and spin tensors

    International Nuclear Information System (INIS)

    Becattini, F.; Tinti, L.

    2011-01-01

    It is shown that different couples of stress-energy and spin tensors of quantum-relativistic fields, which would be otherwise equivalent, are in fact inequivalent if the second law of thermodynamics is taken into account. The proof of the inequivalence is based on the analysis of a macroscopic system at full thermodynamical equilibrium with a macroscopic total angular momentum and a specific instance is given for the free Dirac field, for which we show that the canonical and Belinfante stress-energy tensors are not equivalent. For this particular case, we show that the difference between the predicted angular momentum densities for a rotating system at full thermodynamical equilibrium is a quantum effect, persisting in the nonrelativistic limit, corresponding to a polarization of particles of the order of (ℎ/2π)ω/KT (ω being the angular velocity) and could in principle be measured experimentally. This result implies that specific stress-energy and spin tensors are physically meaningful even in the absence of gravitational coupling and raises the issue of finding the thermodynamically right (or the right class of) tensors. We argue that the maximization of the thermodynamic potential theoretically allows us to discriminate between two different couples, yet for the present we are unable to provide a theoretical method to single out the best couple of tensors in a given quantum field theory. The existence of a nonvanishing spin tensor would have major consequences in hydrodynamics, gravity and cosmology.

  19. Selection for increased desiccation resistance in Drosophila melanogaster: Additive genetic control and correlated responses for other stresses

    International Nuclear Information System (INIS)

    Hoffmann, A.A.; Parsons, P.A.

    1989-01-01

    Previously we found that Drosophila melanogaster lines selected for increased desiccation resistance have lowered metabolic rate and behavioral activity levels, and show correlated responses for resistance to starvation and a toxic ethanol level. These results were consistent with a prediction that increased resistance to many environmental stresses may be genetically correlated because of a reduction in metabolic energy expenditure. Here we present experiments on the genetic basis of the selection response and extend the study of correlated responses to other stresses. The response to selection was not sex-specific and involved X-linked and autosomal genes acting additively. Activity differences contributed little to differences in desiccation resistance between selected and control lines. Selected lines had lower metabolic rates than controls in darkness when activity was inhibited. Adults from selected lines showed increased resistance to a heat shock, 60 Co-gamma-radiation, and acute ethanol and acetic acid stress. The desiccation, ethanol and starvation resistance of isofemale lines set up from the F2s of a cross between one of the selected and one of the control lines were correlated. Selected and control lines did not differ in ether-extractable lipid content or in resistance to acetone, ether or a cold shock

  20. Observation of ultraslow stress release in silicon nitride films on CaF2

    International Nuclear Information System (INIS)

    Guo, Tianyi; Deen, M. Jamal; Xu, Changqing; Fang, Qiyin; Selvaganapathy, P. Ravi; Zhang, Haiying

    2015-01-01

    Silicon nitride thin films are deposited by plasma-enhanced chemical vapor deposition on (100) and (111) CaF 2 crystalline substrates. Delaminated wavy buckles formed during the release of internal compressive stress in the films and the stress releasing processes are observed macroscopically and microscopically. The stress release patterns start from the substrate edges and propagate to the center along defined directions aligned with the crystallographic orientations of the substrate. The stress releasing velocity of SiN x film on (111) CaF 2 is larger than that of SiN x film with the same thickness on (100) CaF 2 . The velocities of SiN x film on both (100) and (111) CaF 2 increase with the film thickness. The stress releasing process is initiated when the films are exposed to atmosphere, but it is not a chemical change from x-ray photoelectron spectroscopy

  1. Correlation between the local stress and the grain misorientation in the polycrystalline Al2O3 measured by near-field luminescence spectroscopy

    Science.gov (United States)

    Tomimatsu, Toru; Takigawa, Ryo

    2018-06-01

    Owing to its high spatial resolution, near-field spectroscopy is a useful method for sensing the stress in a narrow region of submicron order. Here, on the basis of the highly resolved images obtained by near-field luminescence spectroscopy, we propose a statistical method of analyzing grain anisotropy-induced stress in polycrystalline Al2O3. We focus on two characteristics of a spectra: the intensity ratio and peak shift of luminescence of two lines (R1 and R2) from Al2O3 to discuss crystal orientation and stress, respectively. By incorporating the concept of the crystal misorientation parameter using intensity ratio, an apparent correlation between the magnitude of stress and the misorientation is found. This correlation analysis provides an important insight for the investigation of local thermal stress in Al2O3.

  2. [Stress related correlates of anxiety and depression in girls with chronic headache].

    Science.gov (United States)

    Bung, Simone; Saile, Helmut; Laessle, Reinhold

    2018-01-01

    Chronic headache in adolescents is frequent and often associated with anxiety and depression. The present study investigated, whether psychological and physical stress symptoms have an infl uence on the occurrence of anxiety and depression and what is the role of stress coping. The sample consisted of 77 15 years old girls with chronic headache and 72 girls, who served as controls. Stress symptoms and stress coping were measured with the Stressverarbeitungsfragebogen für Kinder und Jugendliche (Coping with Stress Questionnaire for Children and Adolescents), depression was assessed by the Depression Inventory for Children and Adolescents, anxiety by the State-Trait Anxiety Inventory for Children. Linear regression was used to analyze the relationship between stress factors and anxiety resp. depression. Physical stress symptoms were related to anxiety, but not to depression. Coping strategies of the depressed as well as the anxious children were characterized by stress reinforcing behaviors. The results point to focusing on physical symptoms in the anxious headache patients and to avoidance coping in the depressed children.

  3. Yield stress of alumina-zirconia suspensions

    International Nuclear Information System (INIS)

    Ramakrishnan, V.; Pradip; Malghan, S.G.

    1996-01-01

    The yield stress of concentrated suspensions of alumina, zirconia, and mixed alumina-zirconia powders was measured by the vane technique as a function of solids loading, relative amounts of alumina and zirconia, and pH. At the isoelectric point (IEP), the yield stress varied as the fourth power of the solids loading. The relative ratio of alumina and zirconia particles was important in determining the yield stress of the suspension at the IEP. The yield stress of single and mixed suspensions showed a marked variation with pH. The maximum value occurred at or near the IEP of the suspension. The effect of electrical double-layer forces on the yield stress can be described on the basis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. A normalized yield stress--that is, the ratio of the yield stress at a given pH to the yield stress at the IEP predicted by this model--showed good correlation with experimental data

  4. Stress management for optimization oforganizational activity

    Directory of Open Access Journals (Sweden)

    Iuliana Guiţă – Alexandru

    2014-06-01

    Full Text Available Stress is a constant presence in our lives, whether we analyze it in professional, social or family terms. This daily reality creates a state of tension, strain and discomfort, causing significant changes in physical and mental health. Stress at work can affect anyone, at any level, in any sector and in organizations of any size. Stress affects health and safety of individuals and also organizations’ welfare and national economies. There is a definite correlation between the level of stress at work and the changes in organization’s productivity.

  5. [Appraisal of occupational stress and work ability].

    Science.gov (United States)

    Yang, Xinwei; Wang, Zhiming; Lan, Yajia; Wang, Mianzhen

    2004-01-01

    This study was conducted to assess occupational stress and work ability. A test of occupational stress and work ability was carry out with revised occupational stress inventory (OSI-R) and work ability index(WAI) for 2270 workers. (1) The occupational stress and strain in male was significantly higher than those in female, but self-care and social support in female werehigher than in male(P < 0.01). The level of occupational stress, strain except interpersonal strain increased with age, while work ability decreased(P < 0.05). (2) Among 6 items of occupational role questionnaire, the score of role boundary and responsibility were obviously higher in college education (P < 0.05). The score of occupational role, psychological strain, physical strain was higher in maried, divorce than unmarried(P < 0.05). (3) The score of occupational role, strain in good work ability category was significantly lower than others, but personal resources were higher(P < 0.05). (4) The correlation of work ability and occupational stress, strain, personal resources were significant(P < 0.01), occupational role and personal strain were positively correlated, both of which correlated negatively to the personal resources(P < 0.01). (5) The major influential factors of personal strain were age, recreation, self-care, social support, rational/cognitive, role insufficiency, role ambiguity and role boundary.

  6. Bridging scales of crustal stress patterns using the new World Stress Map

    Science.gov (United States)

    Heidbach, O.; Rajabi, M.; Cui, X.; Fuchs, K. W.; Mueller, B.; Reinecker, J.; Reiter, K.; Tingay, M. R. P.; Wenzel, F.; Xie, F.; Ziegler, M.; Zoback, M. D.; Zoback, M. L.

    2017-12-01

    Knowledge of the contemporary crustal stress field is a key parameter for the understanding of geodynamic processes such as global plate tectonics and the earthquake cycle. It is also an essential parameter for our sustainable and safe usage of Earth's resources, which is a major challenge for energy security in the 21st century. Since 1986, the World Stress Map (WSM) project has systematically compiled present-day stress information and provides a unique public domain global database. It is a long-term project based on an international network of partners from academia and industry. All data are public and available on the project website at world-stress-map.org. For the 30th anniversary of the project a new database has been compiled, containing double the amount of data records (n=42,870) including new data records from almost 4,000 deep boreholes. The new compilation focused on areas with previously sparse data coverage in order to resolve the stress pattern on different spatial scales. The significantly higher data density can now be used to resolve stress pattern heterogeneities on regional and local scales, as well as with depth in some regions. We present three results derived from the new WSM compilation: 1.) The global comparison between absolute plate motion and the mean of the orientation of maximum horizontal stress SHmax on a regular grid shows that there is still a correlation for the North and South America plate, but deviations from this general trend are now also clearly resolved. 2.) The variability of the crustal stress pattern changes when zooming in from plate-wide scale down to basin scale at 100 km. We show examples for Eastern Australia, Oklahoma and Central Europe. This regional and local variability of the stress pattern can be used as a proxy to identify and quantify regional and local stress sources by means of geomechanical-numerical models of the 3D stress tensor. 3.) Finally we present briefly the general concept of a multi-stage 3D

  7. Perceived Stress, Sources and Severity of Stress among medical undergraduates in a Pakistani Medical School

    Directory of Open Access Journals (Sweden)

    Malik Samina

    2010-01-01

    Full Text Available Abstract Background Recently there is a growing concern about stress during undergraduate medical training. However, studies about the same are lacking from Pakistani medical schools. The objectives of our study were to assess perceived stress, sources of stress and their severity and to assess the determinants of stressed cases. Methods A cross-sectional, questionnaire-based survey was carried out among undergraduate medical students of CMH Lahore Medical College, Pakistan during January to March 2009. Perceived stress was assessed using the perceived stress scale. A 33-item questionnaire was used to assess sources of stress and their severity. Results The overall response rate was 80.5% (161 out of 200 students. The overall mean perceived stress was 30.84 (SD = 7.01 and was significantly higher among female students. By logistic regression analysis, stressed cases were associated with occurrence of psychosocial (OR 5.01, 95% CI 2.44-10.29 and academic related stressors (OR 3.17 95% CI 1.52-6.68. The most common sources of stress were related to academic and psychosocial concerns. 'High parental expectations', 'frequency of examinations', 'vastness of academic curriculum', 'sleeping difficulties', 'worrying about the future', 'loneliness', 'becoming a doctor', 'performance in periodic examinations' were the most frequently and severely occurring sources of stress. There was a negative but insignificant correlation between perceived stress and academic performance (r = -0.099, p > 0.05. Conclusion A higher level of perceived stress was reported by the students. The main stressors were related to academic and psychosocial domains. Further studies are required to test the association between stressed cases and gender, academic stressors and psychosocial stressors.

  8. Relationship between mental toughness, stress appraisal, and innovation performance of R&D personnel

    Directory of Open Access Journals (Sweden)

    Feng Jin

    2016-01-01

    Full Text Available Four hundred and two R&D personnel were surveyed through questionnaires to study the relationship between mental toughness, stress appraisal (including experience of stress and stress control, and innovation performance. The findings reveal a significant negative correlation between mental toughness and stress experience and a significant positive correlation between mental toughness and both stress control and innovation performance. Furthermore, although the experience of stress was negatively correlated with innovation performance, stress control had the opposite effect. Experience of stress and stress control were the mediating variables for mental toughness and innovation performance, respectively. There was also a significant interaction effect between stress appraisal and mental toughness.

  9. Tensorial analysis of Eshelby stresses in 3D supercooled liquids

    Science.gov (United States)

    Lemaître, Anaël

    2015-10-01

    It was recently proposed that the local rearrangements governing relaxation in supercooled liquids impress on the liquid medium long-ranged (Eshelby) stress fluctuations that accumulate over time. From this viewpoint, events must be characterized by elastic dipoles, which are second order tensors, and Eshelby fields are expected to show up in stress and stress increment correlations, which are fourth order tensor fields. We construct here an analytical framework that permits analyzing such tensorial correlations in isotropic media in view of accessing Eshelby fields. Two spherical bases are introduced, which correspond to Cartesian and spherical coordinates for tensors. We show how they can be used to decompose stress correlations and thus test such properties as isotropy and power-law scalings. Eshelby fields and the predicted stress correlations in an infinite medium are shown to belong to an algebra that can conveniently be described using the spherical tensor bases. Using this formalism, we demonstrate that the inherent stress field of 3D supercooled liquids is power law correlated and carries the signature of Eshelby fields, thus supporting the idea that relaxation events give rise to Eshelby stresses that accumulate over time.

  10. Risk factors for psychological stress among international business travellers.

    Science.gov (United States)

    Striker, J; Luippold, R S; Nagy, L; Liese, B; Bigelow, C; Mundt, K A

    1999-04-01

    This study investigated sources of self reported psychological stress among international business travellers at the World Bank, following up on a previous study showing that travellers submitted more insurance claims for psychological disorders. Hypotheses were that work, personal, family, and health concerns, as well as time zone travel, contribute to travel stress. A travel survey was developed from focus groups and consisted of questions about these potential sources of travel stress. Surveys were sent to a random sample of staff, stratified by number of travel missions, age range, and sex. Canonical correlation analyses estimated the association between key survey items on sources of stress and two measures of travel stress. 498 staff completed the survey. More than a third reported high to very high travel stress. Correlations between predictors and travel stress showed that social and emotional concerns (such as impact of travel on family and sense of isolation) contributed the most to such stress, followed by health concerns, and workload upon return from travel. Surprisingly, time zone travel did not contribute to the self reported stress of these travellers. There were few modifiers of stress, although respondents suggested that a day of rest after travel and reduced workloads would help. The current study confirms clinical impressions about several correlates of travel stress. Similar research with travellers in other organisations could help to determine whether the findings from this study are valid and what measures can be taken to reduce the psychological health risks to travellers.

  11. Stress

    Science.gov (United States)

    ... can be life-saving. But chronic stress can cause both physical and mental harm. There are at least three different types of stress: Routine stress related to the pressures of work, family, and other daily responsibilities Stress brought about ...

  12. Temporal and spatial patterns in wind stress and wind stress curl over the central Southern California Bight

    Science.gov (United States)

    Noble, Marlene A.; Rosenberger, Kurt J.; Rosenfeld, Leslie K.; Robertson, George L.

    2012-01-01

    In 2001, the U.S. Geological Survey, together with several other federal and municipal agencies, began a series of field programs to determine along and cross-shelf transport patterns over the continental shelves in the central Southern California Bight. As a part of these programs, moorings that monitor winds were deployed off the Palos Verdes peninsula and within San Pedro Bay for six 3–4 month summer and winter periods between 2001 and 2008. In addition, nearly continuous records of winds for this 7-year period were obtained from a terrestrial site at the coast and from a basin site offshore of the long-term coastal site. The mean annual winds are downcoast at all sites. The alongshelf components of wind stress, which are the largest part of the low-frequency wind stress fields, are well correlated between basin, shelf and coastal sites. On average, the amplitude of alongshelf fluctuations in wind stress are 3–4 times larger over the offshore basin, compared to the coastal site, irrespective of whether the fluctuations represent the total, or just the correlated portion of the wind stress field. The curl in the large-scale wind stress tends to be positive, especially in the winter season when the mean wind stress is downcoast and larger at the offshore basin site than at the beach. However, since the fluctuation in wind stress amplitudes are usually larger than the mean, periods of weak negative curl do occur, especially in the summer season when the largest normalized differences in the amplitude of wind stress fluctuations are found in the nearshore region of the coastal ocean. Even though the low-frequency wind stress field is well-correlated over the continental shelf and offshore basins, out to distances of 35 km or more from the coast, winds even 10 km inshore of the beach do not represent the coastal wind field, at least in the summer months. The seasonal changes in the spatial structures in wind stress amplitudes suggest that an assessment of the

  13. Strain and stress tensors of rolled uranium plate by Rietveld refinement of TOF neutron-diffraction data

    International Nuclear Information System (INIS)

    Balzar, D.; Popa, N.C.; Vogel, S.

    2010-01-01

    We report the complete macroscopic average strain and stress tensors for a cold-rolled uranium plate, based on the neutron TOF measurements. Both tensors were determined by the least-squares refinement of the interplanar spacings of 19 Bragg reflections. Based on the pole figures, as determined by GSAS, a triclinic sample symmetry of the uranium plate was assumed. Strain and stress are tensile in both the transverse and rolling directions and very small in the normal direction (through the thickness of the plate). Shear strain and stress components are compressive and of significant magnitude.

  14. Protein stress and stress proteins: implications in aging and disease

    Indian Academy of Sciences (India)

    Madhu Sudhan

    2007-04-02

    Apr 2, 2007 ... (iii) modulating protein activity via stabilization and/or maturation to ... Resistance to any physical stress is correlated with longevity in many, if not all .... range of pathologies including cancer, diabetes, immune- problems and ...

  15. The importance of stress percolation patterns in rocks and other polycrystalline materials.

    Science.gov (United States)

    Burnley, P C

    2013-01-01

    A new framework for thinking about the deformation behavior of rocks and other heterogeneous polycrystalline materials is proposed, based on understanding the patterns of stress transmission through these materials. Here, using finite element models, I show that stress percolates through polycrystalline materials that have heterogeneous elastic and plastic properties of the same order as those found in rocks. The pattern of stress percolation is related to the degree of heterogeneity in and statistical distribution of the elastic and plastic properties of the constituent grains in the aggregate. The development of these stress patterns leads directly to shear localization, and their existence provides insight into the formation of rhythmic features such as compositional banding and foliation in rocks that are reacting or dissolving while being deformed. In addition, this framework provides a foundation for understanding and predicting the macroscopic rheology of polycrystalline materials based on single-crystal elastic and plastic mechanical properties.

  16. Correlation between hardness and stress in Al-(Nb, Mo, Ta) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Car, T., E-mail: car@irb.h [Rudjer Boskovic Institute, Division of Materials Science, Bijenicka cesta 54, 10000 Zagreb, P.O.B. 1016 (Croatia); Radic, N. [Rudjer Boskovic Institute, Division of Materials Science, Bijenicka cesta 54, 10000 Zagreb, P.O.B. 1016 (Croatia); Panjan, P.; Cekada, M. [Jozef Stefan Institute, Ljubljana (Slovenia); Tonejc, A. [Department of Physics, Bijenicka cesta 32, 10000 Zagreb, P.O.B. 331 (Croatia)

    2009-06-30

    The thin films of Al{sub x}Nb{sub 1-x} (95 {>=} x {>=} 20), Al{sub x}Mo{sub x} (90 {>=} x {>=} 20) and Al{sub x}Ta{sub 1-x} (95 {>=} x {>=} 20) were prepared by magnetron codeposition at room temperature. The average film thickness was from 325 to 400 nm, depending on the film composition. The structure of the as-deposited films was examined by the X-ray diffraction. The stress of the films was determined from the substrate deformation by the profilometer, and the microhardness (load 2 mN) was examined by the micro- and nano-hardness device. For the purpose of the examination of the hardness, the samples were deposited onto the sapphire wafers, while the examination of the film stress, was performed by using thin glass substrates. For all the Al-(Nb, Mo, Ta) alloy compositions, the microhardness is predominantly under the influence of the harder element, and monotonically decreases with the increase of the aluminum content. However, the microhardness of the amorphous AlTa films was higher than the bulk value of a harder element (Ta) in the alloy. A simple empirical linear relationship between the Vickers hardness, the bulk value hardness of the transition metal (harder element) and the elastic energy fraction of the identation deformation, was established. The elastic energy fraction in the microhardness is also linearly correlated with the stress in films.

  17. Individual-and Setting-Level Correlates of Secondary Traumatic Stress in Rape Crisis Center Staff.

    Science.gov (United States)

    Dworkin, Emily R; Sorell, Nicole R; Allen, Nicole E

    2016-02-01

    Secondary traumatic stress (STS) is an issue of significant concern among providers who work with survivors of sexual assault. Although STS has been studied in relation to individual-level characteristics of a variety of types of trauma responders, less research has focused specifically on rape crisis centers as environments that might convey risk or protection from STS, and no research to knowledge has modeled setting-level variation in correlates of STS. The current study uses a sample of 164 staff members representing 40 rape crisis centers across a single Midwestern state to investigate the staff member-and agency-level correlates of STS. Results suggest that correlates exist at both levels of analysis. Younger age and greater severity of sexual assault history were statistically significant individual-level predictors of increased STS. Greater frequency of supervision was more strongly related to secondary stress for non-advocates than for advocates. At the setting level, lower levels of supervision and higher client loads agency-wide accounted for unique variance in staff members' STS. These findings suggest that characteristics of both providers and their settings are important to consider when understanding their STS. © The Author(s) 2014.

  18. Long-range correlations and fractal dynamics in C. elegans: Changes with aging and stress

    Science.gov (United States)

    Alves, Luiz G. A.; Winter, Peter B.; Ferreira, Leonardo N.; Brielmann, Renée M.; Morimoto, Richard I.; Amaral, Luís A. N.

    2017-08-01

    Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal-tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similar to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.

  19. Teacher Stress Inventory: validation of the Greek version and perceived stress levels among 3,447 educators.

    Science.gov (United States)

    Kourmousi, Ntina; Darviri, Christina; Varvogli, Liza; Alexopoulos, Evangelos C

    2015-01-01

    The Teacher Stress Inventory (TSI) is an instrument for measuring occupational stress in teachers. This study aimed to translate and adapt it for use in Greece, and then assess its reliability and validity. The Greek versions of the TSI and the 14-item Perceived Stress Scale (PSS-14) were posted on all Greek educators' official sites during May 2012. A nationwide sample of 3,447 teachers of all levels and specialties completed the questionnaires via the Internet. Reliability was determined by the calculation of Cronbach's alpha coefficient. Confirmatory factor analysis was conducted and validity was further examined by investigating the correlation of the TSI with the PSS-14 and their association with demographics and work-related factors. Satisfactory Cronbach's alpha values (above 0.70) were found for all TSI dimensions. Confirmatory factor analysis confirmed the two-factor construct of TSI (root mean square error of approximation, comparative fit index, and goodness-of-fit index values were 0.079, 0.956, and 0.951, respectively), confirming the pre-established theory for the two latent variables, Stress Sources and Stress Manifestations. Significant correlations were found between TSI subscales, PSS-14 sex, age, lack of support, and students' difficulties. The Greek version of the TSI was found to have satisfactory psychometric properties, and its use for assessing stress in Greek teachers is warranted.

  20. Evaluation and correlation of stress scores with blood pressure, endogenous cortisol levels, and homocysteine levels in patients with central serous chorioretinopathy and comparison with age-matched controls.

    Science.gov (United States)

    Agarwal, Abhishek; Garg, Monika; Dixit, Nikhil; Godara, Rohini

    2016-11-01

    Stress had been associated with the development of central serous chorioretinopathy (CSC). The study was designed to evaluate the effect of stress on other risk factors of CSC such as serum cortisol levels, serum homocysteine levels, and blood pressure (BP) in CSC patients. To compare stress scores, serum cortisol and serum homocysteine levels, and BP of CSC patients with that of control population and to correlate stress scores of CSC patients with BP, serum cortisol levels, and serum homocysteine levels. Stress scores, serum morning and evening cortisol levels, serum homocysteine levels, systolic and diastolic BP of 54 CSC patients were measured and compared with that of 54 age- and sex-related controls using Student's t-test. Stress scores of CSC patients were correlated with systolic and diastolic BP, serum morning and evening cortisol levels and serum homocysteine levels and Pearson correlation coefficient (r) were calculated. Stress scores, serum homocysteine levels, serum morning and evening cortisol levels, and systolic and diastolic BP were all elevated in CSC patients as compared with age- and sex-related controls (P Stress scores of CSC patients were found to correlate strongly with serum homocysteine levels, serum morning and evening cortisol levels, and systolic and diastolic BP, with r values 0.82, 0.8, 0.8, 0.8, and 0.81, respectively (P Stress scores were elevated in CSC patients and were strongly correlated with serum homocysteine and cortisol levels and BP.

  1. Correlation among academic stress, academic burnout, and academic performance in nursing and paramedic students of Qom University of Medical Sciences, Iran

    Directory of Open Access Journals (Sweden)

    hamid Asayesh

    2016-09-01

    Full Text Available Background and Objectives: Learning is a stressful experience of human life; reduced adaption to stressors causes academic burnout which is a reason for academic failure among students. This study investigated the correlation among academic stress, academic burnout, and academic performance in nursing and paramedic students of Qom University of Medical Sciences. Methods: In this descriptive, cross-sectional study, 264 nursing and paramedic students were randomly selected. Demographic characteristics checklist, academic burnout questionnaire, and academic stress scale were used to gather data, and grade point average was considered to be the indicator of academic performance. Linear regression analysis was used to analyze the data. The level of significance was considered to be p<0.05. Results: The mean score for students' academic burnout was 28.52±15.84. Univariate regression analysis showed that the students' employment, years of education, academic performance, and all academic stress subscales had a significant correlation with academic burnout. According to multivariate regression analysis, having a field of study-related occupation was a protective factor and academic stress a risk factor for academic burnout. Conclusion: The findings of this study showed that a large proportion of students experienced academic burnout, and students with higher levels of stress experienced more severe academic burnout and had poorer performance. Therefore, training ways to cope with stress can cause reduction in academic burnout and improvement of performance.

  2. Does the arrival index predict physiological stress reactivity in children.

    Science.gov (United States)

    de Veld, Danielle M J; Riksen-Walraven, J Marianne; de Weerth, Carolina

    2014-09-01

    Knowledge about children's stress reactivity and its correlates is mostly based on one stress task, making it hard to assess the generalizability of the results. The development of an additional stress paradigm for children, that also limits stress exposure and test time, could greatly advance this field of research. Research in adults may provide a starting point for the development of such an additional stress paradigm, as changes in salivary cortisol and alpha-amylase (sAA) over a 1-h pre-stress period in the laboratory correlated strongly with subsequent reactivity to stress task (Balodis et al., 2010, Psychoneuroendocrinology 35:1363-73). The present study examined whether such strong correlations could be replicated in 9- to 11-year-old children. Cortisol and sAA samples were collected from 158 children (83 girls) during a 2.5-h visit to the laboratory. This visit included a 1-h pre-stress period in which children performed some non-stressful tasks and relaxed before taking part in a psychosocial stress task (TSST-C). A higher cortisol arrival index was significantly and weakly correlated with a higher AUCg but unrelated to cortisol reactivity to the stressor. A higher sAA arrival index was significantly and moderately related to lower stress reactivity and to a lower AUCi. Children's personality and emotion regulation variables were unrelated to the cortisol and sAA arrival indices. The results of this study do not provide a basis for the development of an additional stress paradigm for children. Further replications in children and adults are needed to clarify the potential meaning of an arrival index.

  3. Risk factors for psychological stress among international business travellers

    Science.gov (United States)

    Striker, J.; Luippold, R. S.; Nagy, L.; Liese, B.; Bigelow, C.; Mundt, K. A.

    1999-01-01

    OBJECTIVES: This study investigated sources of self reported psychological stress among international business travellers at the World Bank, following up on a previous study showing that travellers submitted more insurance claims for psychological disorders. Hypotheses were that work, personal, family, and health concerns, as well as time zone travel, contribute to travel stress. METHODS: A travel survey was developed from focus groups and consisted of questions about these potential sources of travel stress. Surveys were sent to a random sample of staff, stratified by number of travel missions, age range, and sex. Canonical correlation analyses estimated the association between key survey items on sources of stress and two measures of travel stress. RESULTS: 498 staff completed the survey. More than a third reported high to very high travel stress. Correlations between predictors and travel stress showed that social and emotional concerns (such as impact of travel on family and sense of isolation) contributed the most to such stress, followed by health concerns, and workload upon return from travel. Surprisingly, time zone travel did not contribute to the self reported stress of these travellers. There were few modifiers of stress, although respondents suggested that a day of rest after travel and reduced workloads would help. CONCLUSIONS: The current study confirms clinical impressions about several correlates of travel stress. Similar research with travellers in other organisations could help to determine whether the findings from this study are valid and what measures can be taken to reduce the psychological health risks to travellers.   PMID:10450241

  4. Flow stress anisotropy caused by geometrically necessary boundaries

    DEFF Research Database (Denmark)

    Hansen, N.; Juul Jensen, D.

    1992-01-01

    of dislocations. A model has been proposed for this microstructural anisotropy based on the assumptions that (i) the average slip plane is at an angle of 45-degrees to the direction of the applied stress and that (ii) a strengthening parameter is the mean distance in the slip plane between the geometrically...... necessary boundaries. For different macroscopic arrangements of such boundaries, the model predictions are in good qualitative and quantitative agreement with experiments....

  5. Stress analysis of local blisters coupling Raman spectroscopy and X-ray diffraction. Correlation between experimental results and continuous damage modelling for buckling in an iron oxide/phosphated iron system

    Energy Technology Data Exchange (ETDEWEB)

    Panicaud, B., E-mail: benoit.panicaud@utt.fr [Universite de Technologie de Troyes (UTT), CNRS UMR 6279, 12 rue Marie Curie, 10010 Troyes (France); Grosseau-Poussard, J.L. [LEMMA, Pole Sciences et Technologie, Universite de La Rochelle, Av. M. Crepeau, 17042 La Rochelle Cedex (France)

    2010-12-01

    In this present work, local stress development in the iron oxide layers growing on phosphated {alpha}-Fe at 400 deg. C in ambient air is investigated by Raman spectroscopy. Coupled with X-ray diffraction it enables to obtain directly local stresses' maps in the oxide layers. Use of Raman spectroscopy allows obtaining better accuracy on mechanical behaviour at local scale. This characterisation technique is very useful to study systems developing mechanical heterogeneities on surface, especially in case of buckling phenomenon. Investigations on particular local blisters have been done to measure some characteristic lengths at local scale. From local measurements, we are able to evaluate general effect of buckling from simplified scale transition. So, a macroscopic approach has been performed to calculate global stress evolution of the oxide layer, based on continuous damage mechanics. Consequently, it leads to good comparison between modelling and experimental values (global stresses versus oxidation time) in {alpha}-Fe{sub 2}O{sub 3} oxide.

  6. Mean stress effects on high-cycle fatigue of Alloy 718

    International Nuclear Information System (INIS)

    Korth, G.E.

    1980-07-01

    This report covers an investigation of the effects of tensile mean stress on the high-cycle fatigue properties of Alloy 718. Three test temperatures (24, 427, and 649 degree C) were employed, and there were tests in both strain and load control. Results were compared with three different models: linear Modified-Goodman, Peterson cubic, and stress-strain parameter. The linear Modified-Goodman model gave good correlation with actual test data for low and moderate mean stress values, but the stress-strain parameter showed excellent correlation over the entire range of possible mean stresses and therefore is recommended for predicting mean stress effects of Alloy 718. 13 refs., 12 figs

  7. Correlates of Posttraumatic Stress Disorder Symptoms in Marines Back from War

    Science.gov (United States)

    2010-02-01

    et al. (2008). Risk factors for post - traumatic stress disorder amongUKArmed Forces personnel. Psychological Medicine, 38, 511–522. King, D.W., King...Slymen, D. J., Sallis, J. F., & Kritz- Silverstein, D. (2008). New onset and persistent symptoms of post - traumatic stress disorder self reported...objective of this study was to identify factors associated with possible posttraumatic stress disorder ( PTSD ). A questionnaire was completed by 1,569

  8. Vitamin E levels in preeclampsia placenta tissue and its correlation with oxidative stress injury and apoptosis

    Directory of Open Access Journals (Sweden)

    Jun Li

    2017-04-01

    Full Text Available Objective: To study the vitamin E levels in preeclampsia placenta tissue and its correlation with oxidative stress injury and apoptosis. Methods: A total of 60 pregnant women with preeclampsia who received treatment and gave birth in our hospital between July 2012 and January 2016 were collected and divided into mild preeclampsia group (n=41 and severe preeclampsia group (n=19 according to the disease severity; 38 normal pregnant women who received pregnancy test and gave birth in our hospital during the same period were selected as healthy control group. The placental tissue samples of three groups of research subjects were retained, high performance liquid chromatograph-mass spectrometry was used to detect VitE levels in tissue grinding fluid, automatic biochemical analyzer was used to detect the levels of oxidative stress injury indexes, and fluorescence quantitative PCR method was used to detect the mRNA expression of apoptosis molecules. Results: VitE, SOD and CAT levels in grinding fluid of severe preeclampsia group were lower than those of mild preeclampsia group and healthy control group while ROS and AOPP levels were higher than those of mild preeclampsia group and healthy control group; Fas, caspase and Apaf-1 mRNA expression were higher than those of mild preeclampsia group and healthy control group while anti-apoptotic molecules Bcl-2, Bcl-xl, Mcl-2 and p57kip2 mRNA expression were lower than those of mild preeclampsia group and healthy control group. Spearman correlation analysis showed that VitE level in the preeclampsia placenta tissue was directly correlated with oxidative stress injury and cell apoptosis. Conclusion: VitE deficiency is the direct factor that results in oxidative stress and cell apoptosis in patients with preeclampsia, and the VitE supplementation in time is expected to become the auxiliary treatment means for patients with preeclampsia.

  9. Drinking behaviors by stress level in Korean university students.

    Science.gov (United States)

    Chung, Hye-Kyung; Lee, Hae-Young

    2012-04-01

    The purposes of this study are to estimate the stress level of university students, and to verify the relationships between stress level and drinking behavior. A questionnaire survey was administered to 430 university students in the Gangwon area in Korea from November 5 to November 28, 2008, and data from 391 students were used for the final statistical analysis. The most stressful factor was "Worry about academic achievements" (2.86 by Likert-type 4 point scale). The subjects were divided into two groups, a low stress group (≤ 65.0) and a high stress group (≥ 66.0), by the mean value (65.1) and median value (66.0) of the stress levels. The drinking frequency was not different between the two stress groups, but the amount of alcohol consumption was significantly different (P stress group than in the higher stress group. In addition, factor 6, "Lack of learning ability", was negatively correlated with drinking frequency and the amount of alcohol consumption (P academic achievements", was negatively correlated with the amount of drinking (P stress group showed significantly higher scores on several items in the categories of motives (P stress group. Our results imply that university students at the lower stress level may drink more from social motives in positive drinking environments, while those at the higher stress level may have more problematic-drinking despite their smaller amount of alcohol consumption.

  10. Teacher Stress Inventory: validation of the Greek version and perceived stress levels among 3,447 educators

    Directory of Open Access Journals (Sweden)

    Kourmousi N

    2015-03-01

    Full Text Available Ntina Kourmousi, Christina Darviri, Liza Varvogli, Evangelos C Alexopoulos School of Medicine, University of Athens, Athens, Greece Background: The Teacher Stress Inventory (TSI is an instrument for measuring occupational stress in teachers. This study aimed to translate and adapt it for use in Greece, and then assess its reliability and validity. Methods: The Greek versions of the TSI and the 14-item Perceived Stress Scale (PSS-14 were posted on all Greek educators' official sites during May 2012. A nationwide sample of 3,447 teachers of all levels and specialties completed the questionnaires via the Internet. Reliability was determined by the calculation of Cronbach's alpha coefficient. Confirmatory factor analysis was conducted and validity was further examined by investigating the correlation of the TSI with the PSS-14 and their association with demographics and work-related factors. Results: Satisfactory Cronbach's alpha values (above 0.70 were found for all TSI dimensions. Confirmatory factor analysis confirmed the two-factor construct of TSI (root mean square error of approximation, comparative fit index, and goodness-of-fit index values were 0.079, 0.956, and 0.951, respectively, confirming the pre-established theory for the two latent variables, Stress Sources and Stress Manifestations. Significant correlations were found between TSI subscales, PSS-14 sex, age, lack of support, and students' difficulties. Conclusion: The Greek version of the TSI was found to have satisfactory psychometric properties, and its use for assessing stress in Greek teachers is warranted. Keywords: TSI, reliability, validity, Greek educators, occupational stress, psychosocial factors

  11. A description of stress driven bubble growth of helium implanted tungsten

    International Nuclear Information System (INIS)

    Sharafat, Shahram; Takahashi, Akiyuki; Nagasawa, Koji; Ghoniem, Nasr

    2009-01-01

    Low energy (<100 keV) helium implantation of tungsten has been shown to result in the formation of unusual surface morphologies over a large temperature range (700-2100 deg. C). Simulation of these macroscopic phenomena requires a multiscale approach to modeling helium transport in both space and time. We present here a multiscale helium transport model by coupling spatially-resolved kinetic rate theory (KRT) with kinetic Monte Carlo (KMC) simulation to model helium bubble nucleation and growth. The KRT-based HEROS Code establishes defect concentrations as well as stable helium bubble nuclei as a function of implantation parameters and position from the implanted surface and the KMC-based Mc-HEROS Code models the growth of helium bubbles due to migration and coalescence. Temperature- and stress-gradients can act as driving forces, resulting in biased bubble migration. The Mc-HEROS Code was modified to simulate the impact of stress gradients on bubble migration and coalescence. In this work, we report on bubble growth and gas release of helium implanted tungsten W/O stress gradients. First, surface pore densities and size distributions are compared with available experimental results for stress-free helium implantation conditions. Next, the impact of stress gradients on helium bubble evolution is simulated. The influence of stress fields on bubble and surface pore evolution are compared with stress-free simulations. It is shown that near surface stress gradients accelerate helium bubbles towards the free surface, but do not increasing average bubble diameters significantly.

  12. Mastery over stress among women with HIV/AIDS.

    Science.gov (United States)

    Gray, Jennifer; Cason, Carolyn L

    2002-01-01

    To better understand how women with HIV infection deal with the stress of their disease, the authors explored the relationships between stressors, resources for managing stress, and mastery over stress in 80 HIV-positive women. Nurses and other professionals recruited participants in a variety of settings in 10 states. Participants completed a packet of research instruments that measured the stressors of perceived stress intensity, interpersonal conflict, and severity of illness; the resources of social support, support networks, and spiritual perspective; and the outcome of mastery over stress. Participants reported high levels of social support, spiritual perspective, interpersonal conflict, and perceived stress intensity. Twenty-nine women (36%) had achieved mastery over stress. Mastery over stress was significantly and positively correlated with social support, spiritual perspective, and physical functioning, a measure of severity of illness. Mastery over stress was significantly and negatively correlated with interpersonal conflict. An exploratory stepwise multiple regression analysis yielded two predictors of mastery over stress: social support and spiritual perspective. Although a comparison of these results with those reported in the literature for men suggests that men and women differ in how they respond to stressors, further research will be needed to enhance our understanding of these gender differences. Stress management training, especially related to interpersonal conflict, may be an effective intervention to facilitate mastery. Other potential interventions include assessing social support and spiritual perspective, discussing the potential benefit of these resources, and making referrals for psychosocial services as needed.

  13. Parenting stress in parents of children with cochlear implants: relationships among parent stress, child language, and unilateral versus bilateral implants.

    Science.gov (United States)

    Sarant, Julia; Garrard, Philippa

    2014-01-01

    Little attention has been focused on stress levels of parents of children with cochlear implants (CIs). This study examined the stress experience of 70 parents of children with CIs by comparing stress levels in this group of parents to those in parents of children without disabilities, identifying primary stressors, examining the relationship between parent stress and child language, and comparing stress in parents of children with bilateral and unilateral CIs. Parents completed a parent stress questionnaire, and the receptive vocabulary and language abilities of the children were evaluated. Results indicated that these parents had a higher incidence of stress than the normative population. Parent stress levels and child language outcomes were negatively correlated. Child behavior and lack of spousal and social support were the prime causes of parent stress. Parents of children with bilateral CIs were significantly less stressed than were parents of children with unilateral CIs.

  14. Estimating minimum polycrystalline aggregate size for macroscopic material homogeneity

    International Nuclear Information System (INIS)

    Kovac, M.; Simonovski, I.; Cizelj, L.

    2002-01-01

    During severe accidents the pressure boundary of reactor coolant system can be subjected to extreme loadings, which might cause failure. Reliable estimation of the extreme deformations can be crucial to determine the consequences of severe accidents. Important drawback of classical continuum mechanics is idealization of inhomogenous microstructure of materials. Classical continuum mechanics therefore cannot predict accurately the differences between measured responses of specimens, which are different in size but geometrical similar (size effect). A numerical approach, which models elastic-plastic behavior on mesoscopic level, is proposed to estimate minimum size of polycrystalline aggregate above which it can be considered macroscopically homogeneous. The main idea is to divide continuum into a set of sub-continua. Analysis of macroscopic element is divided into modeling the random grain structure (using Voronoi tessellation and random orientation of crystal lattice) and calculation of strain/stress field. Finite element method is used to obtain numerical solutions of strain and stress fields. The analysis is limited to 2D models.(author)

  15. Phylogenetic diversity of stress signalling pathways in fungi

    Directory of Open Access Journals (Sweden)

    Stansfield Ian

    2009-02-01

    Full Text Available Abstract Background Microbes must sense environmental stresses, transduce these signals and mount protective responses to survive in hostile environments. In this study we have tested the hypothesis that fungal stress signalling pathways have evolved rapidly in a niche-specific fashion that is independent of phylogeny. To test this hypothesis we have compared the conservation of stress signalling molecules in diverse fungal species with their stress resistance. These fungi, which include ascomycetes, basidiomycetes and microsporidia, occupy highly divergent niches from saline environments to plant or mammalian hosts. Results The fungi displayed significant variation in their resistance to osmotic (NaCl and sorbitol, oxidative (H2O2 and menadione and cell wall stresses (Calcofluor White and Congo Red. There was no strict correlation between fungal phylogeny and stress resistance. Rather, the human pathogens tended to be more resistant to all three types of stress, an exception being the sensitivity of Candida albicans to the cell wall stress, Calcofluor White. In contrast, the plant pathogens were relatively sensitive to oxidative stress. The degree of conservation of osmotic, oxidative and cell wall stress signalling pathways amongst the eighteen fungal species was examined. Putative orthologues of functionally defined signalling components in Saccharomyces cerevisiae were identified by performing reciprocal BLASTP searches, and the percent amino acid identities of these orthologues recorded. This revealed that in general, central components of the osmotic, oxidative and cell wall stress signalling pathways are relatively well conserved, whereas the sensors lying upstream and transcriptional regulators lying downstream of these modules have diverged significantly. There was no obvious correlation between the degree of conservation of stress signalling pathways and the resistance of a particular fungus to the corresponding stress. Conclusion Our

  16. Assessment of Workplace Stress: Occupational Stress, Its Consequences, and Common Causes of Teacher Stress.

    Science.gov (United States)

    Hansen, Jo-Ida; Sullivan, Brandon A.

    This chapter introduces teachers and other education professionals to the assessment of occupational stress. It begins with a brief discussion of what occupational stress is, and overview of the consequences of prolonged stress, and a review of the common causes of teacher stress. Next, it presents methods for reducing occupational stress through…

  17. Stress management for optimization oforganizational activity

    OpenAIRE

    Iuliana Guiţă – Alexandru

    2014-01-01

    Stress is a constant presence in our lives, whether we analyze it in professional, social or family terms. This daily reality creates a state of tension, strain and discomfort, causing significant changes in physical and mental health. Stress at work can affect anyone, at any level, in any sector and in organizations of any size. Stress affects health and safety of individuals and also organizations’ welfare and national economies. There is a definite correlation between the level...

  18. Study on the Correlation between PSR and Korean Stress Test for Continued Operation of Aging NPP

    International Nuclear Information System (INIS)

    Chung, June Ho; Kim, Tae Ryong

    2013-01-01

    acceptance. Therefore, it is highly recommended and necessary to include the Korean Stress Test into the regulation system of CO evaluation. In that event, it is advisable that the related guidelines and regulations should be revised based on the updated IAEA PSR guideline. The correlation of assessment items between the PSR and the Korean Stress Test should also be reflected in the revision

  19. PNNL Stress/Strain Correlation for Zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Geelhood, Kenneth J.; Beyer, Carl E.; Luscher, Walter G.

    2008-07-18

    Pacific Northwest National Laboratory (PNNL) was tasked with incorporating cladding mechanical property data into the Nuclear Regulatory Commission (NRC) fuel codes, FRAPCON-31 and FRAPTRAN2, by the NRC Office of Nuclear Reactor Research. The objective of that task was to create a mechanical model that can calculate true stress, true strain, and the possible failure of the fuel rod cladding based on uniaxial test data.

  20. Family stress and posttraumatic stress: the impact of military operations on military health care providers.

    Science.gov (United States)

    Gibbons, Susanne W; Barnett, Scott D; Hickling, Edward J

    2012-08-01

    This study uses data from the 2005 Department of Defense Survey of Health-Related Behaviors Among Military Personnel to examine relationships between family stress and posttraumatic stress symptoms across 4 subgroups of Operation Iraqi Freedom-deployed (i.e., war in Iraq) or Operation Enduring Freedom-deployed (i.e., war in Afghanistan) active-duty military service members. Results suggest the following: (a) the greatest positive correlation of family stressors with posttraumatic stress symptoms was found within the military health care officer group, and (b) these military health care officers differed in family stressors mediating posttraumatic stress with divorce and financial problems accounting for significant and unique portions of the variance. Implications for care of service members and their families are discussed. Published by Elsevier Inc.

  1. Psychological stress during exercise: immunoendocrine and oxidative responses.

    Science.gov (United States)

    Huang, Chun-Jung; Webb, Heather E; Evans, Ronald K; McCleod, Kelly A; Tangsilsat, Supatchara E; Kamimori, Gary H; Acevedo, Edmund O

    2010-12-01

    The purpose of this study was to examine the changes in catecholamines (epinephrine [EPI] and norepinephrine [NE]), interleukin-2 (IL-2) and a biomarker of oxidative stress (8-isoprostane) in healthy individuals who were exposed to a dual challenge (physical and psychological stress). Furthermore, this study also examined the possible relationships between catecholamines (NE and EPI) and 8-isoprostane and between IL-2 and 8-isoprostane following a combined physical and psychological challenge. Seven healthy male subjects completed two experimental conditions. The exercise-alone condition (EAC) consisted of cycling at 60% VO(2max) for 37 min, while the dual-stress condition (DSC) included 20 min of a mental challenge while cycling. DSC showed greater EPI and 8-isoprostane levels (significant condition by time interaction). NE and IL-2 revealed significant change across time in both conditions. In addition, following dual stress, EPI area-under-the-curve (AUC) demonstrated a positive correlation with NE AUC and IL-2 AUC. NE AUC was positively correlated with IL-2 AUC and peak 8-isoprostane, and peak IL-2 was positively correlated with peak 8-isoprostane in response to a dual stress. The potential explanation for elevated oxidative stress during dual stress may be through the effects of the release of catecholamines and IL-2. These findings may further provide the potential explanation that dual stress alters physiological homeostasis in many occupations including firefighting, military operations and law enforcement. A greater understanding of these responses to stress can assist in finding strategies (e.g. exercise training) to overcome the inherent psychobiological challenges associated with physically and mentally demanding professions.

  2. Correlation of stress with outcome of radioiodine therapy for Graves disease

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, T.; Rochon, J.; Lenfestey, R.; Wise, P.

    1985-06-01

    Between November 1965 and December 1983, 293 patients were treated for Graves disease using /sup 131/I. All patients were asked to identify a stressful event antedating the onset of overt clinical symptoms. Eighty-one patients were able to do this (27.6%). Two hundred forty-four patients received a single treatment, 49 required two or more treatments. Patients with stress initiating the symptoms of Graves disease became hypothyroid earlier, 50% at 12 mo compared with 36 mo for the nonstress group. At 10 yr 5% of the stress group remained euthyroid compared with 17% nonstress. The authors conclude that stress in the 12 mo or less before the onset of clinical symptoms potentiates the development of hypothyroidism induced by a standard dose of radioiodine.

  3. Stress, memory and the amygdala.

    Science.gov (United States)

    Roozendaal, Benno; McEwen, Bruce S; Chattarji, Sumantra

    2009-06-01

    Emotionally significant experiences tend to be well remembered, and the amygdala has a pivotal role in this process. But the efficient encoding of emotional memories can become maladaptive - severe stress often turns them into a source of chronic anxiety. Here, we review studies that have identified neural correlates of stress-induced modulation of amygdala structure and function - from cellular mechanisms to their behavioural consequences. The unique features of stress-induced plasticity in the amygdala, in association with changes in other brain regions, could have long-term consequences for cognitive performance and pathological anxiety exhibited in people with affective disorders.

  4. Countermeasures to stress corrosion cracking by stress improvement

    International Nuclear Information System (INIS)

    Umemoto, Tadahiro

    1983-01-01

    One of the main factors of the grain boundary stress corrosion cracking occurred in the austenitic stainless steel pipes for reactor cooling system was the tensile residual stress due to welding, and a number of methods have been proposed to reduce the residual stress or to change it to compressive stress. In this paper, on the method of improving residual stress by high frequency heating, which has been applied most frequently, the principle, important parameters and the range of application are explained. Also the other methods of stress improvement are outlined, and the merit and demerit of respective methods are discussed. Austenitic stainless steel and high nickel alloys have good corrosion resistance, high toughness and good weldability, accordingly they have been used for reactor cooling system, but stress corrosion cracking was discovered in both BWRs and PWRs. It occurs when the sensitization of materials, tensile stress and the dissolved oxygen in high temperature water exceed certain levels simultaneously. The importance of the residual stress due to welding, induction heating stress improvement, and other methods such as heat sink welding, last pass heat sink welding, back lay welding and TIG torch heating stress improvement are described. (Kako, I.)

  5. Individual modulation of pain sensitivity under stress.

    Science.gov (United States)

    Reinhardt, Tatyana; Kleindienst, Nikolaus; Treede, Rolf-Detlef; Bohus, Martin; Schmahl, Christian

    2013-05-01

    Stress has a strong influence on pain sensitivity. However, the direction of this influence is unclear. Recent studies reported both decreased and increased pain sensitivities under stress, and one hypothesis is that interindividual differences account for these differences. The aim of our study was to investigate the effect of stress on individual pain sensitivity in a relatively large female sample. Eighty female participants were included. Pain thresholds and temporal summation of pain were tested before and after stress, which was induced by the Mannheim Multicomponent Stress Test. In an independent sample of 20 women, correlation coefficients between 0.45 and 0.89 indicated relatively high test-retest reliability for pain measurements. On average, there were significant differences between pain thresholds under non-stress and stress conditions, indicating an increased sensitivity to pain under stress. No significant differences between non-stress and stress conditions were found for temporal summation of pain. On an individual basis, both decreased and increased pain sensitivities under stress conditions based on Jacobson's criteria for reliable change were observed. Furthermore, we found significant negative associations between pain sensitivity under non-stress conditions and individual change of pain sensitivity under stress. Participants with relatively high pain sensitivity under non-stress conditions became less sensitive under stress and vice versa. These findings support the view that pain sensitivity under stress shows large interindividual variability, and point to a possible dichotomy of altered pain sensitivity under stress. Wiley Periodicals, Inc.

  6. Perceived stress in dental practice.

    Science.gov (United States)

    Pop-Jordanova, Nada; Radojkova-Nikolovska, Vera; Markovska-Simoska, Silvana

    2013-01-01

    Stress is a normal physiological response to events that make us feel threatened, or upset our balance in some way. In medicine, it is known that stress, as an emotional state, can be a trigger for many psychosomatic disorders. Work stress and burnout are considered to be serious professional risks in dentistry. The dentist should be aware of these stressors and attempt to manage them in order to avoid becoming occupationally dissatisfied. On the other hand, the other common characteristic of modern life is a growing burden of different chronic diseases. Periodontal disease is one of the two most important oral diseases contributing to the global burden of chronic disease. The aim of this study was to assess the perceived stress in patients with periodontal pathologies, and to compare it with the stress in doctors-dentists and students of dentistry as future professionals. Our study confirmed the presence of significant stress in all three groups of examinees (patients, doctors, and students). Surprisingly, the obtained PSQ scores are similar in the examined groups. In addition, no differences between perceived stress in males and females have been found. There is a minimal positive correlation between age and obtained scores. However, stress must be evaluated as a risk factor both for professionals or for chronic dental patients and some response measures must be undertaken.

  7. Correlation between oxidation and stress corrosion cracking of U-4.5 wt.% Nb

    International Nuclear Information System (INIS)

    Magnani, N.J.; Holloway, P.H.

    1976-01-01

    To investigate the mechanisms causing stress corrosion cracking on uranium alloys, the kinetics of crack propagation and oxide film growth for U-4.5 percent Nb were investigated at temperatures between 0 0 C and 200 0 C in oxygen, water vapor and oxygen-water vapor mixtures. Three regions of crack velocity rate versus stress intensity were observed in laboratory air. At low stress intensities (but above an effective K/sub ISCC/ of 22 MN/m/sup 3 / 2 /) crack velocity varied approximately as K 70 . In an intermediate stress intensity region (region II) the crack velocity was dependent upon K 4 . In the high stress intensity region, mechanical overloading was observed and crack velocities varied approximately as K 12 . Both cracking (region II) and oxidation rates were characterized by an activation energy of 7 kcal/mole. For stress corrosion cracking it was shown that oxygen was the primary stress corrodent, but a synergistic effect upon crack propagation rates was observed for oxygen-water vapor mixtures. Crack velocities were dependent upon the pressure of oxygen (P/sub O 2 //sup 1 / 3 /) and water vapor, while the oxidation rate was essentially independent of the pressure of these species. Stress sorption and oxide film formation stress corrosion cracking mechanisms were considered and reconciled with the stress corrosion and oxidation data

  8. The role of stress in IBS symptom severity

    Directory of Open Access Journals (Sweden)

    Sanda Pletikosic

    2016-04-01

    Full Text Available Irritable bowel syndrome is regarded as a biopsychosocial disorder, the result of a complex combination of predisposing, precipitating and perpetuating factors. Personality traits, affective status and stress are some of the relevant factors contributing to lower quality of life and symptom exacerbation in IBS patients. In order to examine the role of stress in IBS symptom exacerbation, the aims of this study were to explore the relationship of daily stressful events and symptom severity in a prospective manner and to explore the roles of neuroticism, anxiety, depression and stress in the vicious circle of symptom perpetuation. A total of 49 patients with IBS reported their symptom severity and daily stressful events intensity each day for 14 consecutive days. They also completed the Big five personality inventory, the Beck Depression Inventory and the State-trait anxiety inventory. Cross-correlation analyses were performed on the time series data for daily stress and symptom severity for each participant separately. Four different patterns of relationships were found in different subgroups of participants: positive cross-correlations of symptom severity and stress intensity on the same day; higher symptom severity on days following stressful days; lower symptom severity on days following stressful days; and lower stress intensity on days following severe symptoms. Using average scores for daily stress and symptom severity, as well as scores for neuroticism, anxiety and depression, we performed a path analysis to test a model of symptom exacerbation. It showed that, on the group level, average stress intensity predicts average symptom severity. Neuroticism and anxiety were not significant predictors of symptom severity, while depression showed a marginally significant relationship with symptom severity, mediated by stress intensity. In conclusion, depression and daily stress seem to be important contributors to the vicious circle of IBS symptom

  9. Mood and food at the University of Turku in Finland: nutritional correlates of perceived stress are most pronounced among overweight students.

    Science.gov (United States)

    El Ansari, Walid; Suominen, Sakari; Berg-Beckhoff, Gabriele

    2015-09-01

    We examined perceived stress and food intake at University of Turku, Finland. This study was conducted as an online survey (1189 students). We computed two composite food intake pattern scores (sweets, cakes and snacks; fruits and vegetables), a dietary guideline adherence index, and the subjective importance of healthy eating. We assessed the correlations between perceived stress, and two food intake pattern scores, dietary guideline adherence index and subjective importance of healthy eating. We tested the associations between stress and the same variables, controlling for potential confounders for the whole sample, by gender, and by Body Mass Index (BMI). Fruits and vegetables intake and dietary guideline adherence were both negatively associated with stress. These negative associations were more pronounced in overweight and less pronounced in underweight compared to healthy weight students. Sweets, cookies and snacks consumption were not associated with stress. Stress was associated with lower subjective importance of healthy eating, independent of gender and BMI. Perceived stress might have relationships of different magnitudes in overweight vs. normal BMI or underweight persons. BMI could be an effect modifier of the stress-food habits association.

  10. Correlation of anti-stress ability of nuclear power plant operators with physiological and psychological indexes

    International Nuclear Information System (INIS)

    Liao Haihong; Liu Yulong; Li Yuan; Dai Tingting; Qiu Mengyue; Bian Huahui; Chen Weibo; Liu Chunfeng

    2012-01-01

    Objective: To explore the correlation of the anti-stress ability of nuclear power plant operators with their heart rate, blood pressure and mental health. Methods: A total of 136 male nuclear power plant operators received the continuous performance test (CPT) and mental health test (MHT), while 37 male senior students were used as the control group. Heart rate and blood pressure were recorded before and after the test. The nuclear power plant operators were divided to high score group and low score group by CPT scores. The correlation of the anti-stress ability and blood pressure,heart rate and their mental health was analyzed. Results: The scores of CPT and MHT test with the operators were significantly higher than those of the control group (t=-1.25, 6.25, P<0.05). After the test, the heart rate, systolic pressure and diastolic pressure of the operators were all significantly lower than those of the control group (t=-2.07, 3.28, 2.74, P<0.05). The CPT score of the high score group was lower in the heart rate, systolic pressure and diastolic pressure than the low score group (t=-3.15, -2.78, -2.54, P<0.05), while the scores of CPT and MHT were better (t=0.63, 6.90, P<0.05). CPT scores were negatively correlated with the increasing range of the heart rate, systolic pressure and diastolic pressure (r=- 0.69, -0.94, and -0.62, P<0.05), and positively correlated with the MHT scores (r=0.54, P<0.05). Conclusions: To a certain extent, CPT and MHT test can reflect the anti-stress ability and be used as one of the bases to select nuclear power plant operators and to assess their competence. (authors)

  11. Semi-integration of overcoring stress data and review of rock stress data at the Olkiluoto site

    International Nuclear Information System (INIS)

    Ask, D.

    2011-06-01

    field from all stress measurement techniques. The variability in results is visualized by the low consistency of overcoring strains with the various constraints, although they clearly may represent also improperly defined constraints but may also reflect a reduced data quality or limitations of the acceptance criteria and algorithm. What can be concluded is that one principal stress is indeed vertical (or near vertical) and closely resembles the theoretical weight of the overburden. The results of constraining also horizontal stress orientations and magnitudes are though much less clear. Most likely, σ H is directed NW-SW, i.e. a quite imprecise result. The report also involved analysis of observed core discing. The results of this study show that dominating disc type at the Olkiluoto site is the incomplete disc (52 % of all observations) and the dominating host rock pegmatitic granite (PGR; 49 % of all observations). Discing events with other disc shapes and in other rock types are significantly less frequent. The discing events could not be correlated with existing and larger deformation zones, although discing events may possibly be correlated to zone OL-BFZ002. Note that the analysis has only been made with respect to the major deformation zones, which does not preclude that discing events may be correlated to smaller scale zones

  12. Investigation heat stress in small enterprise in Qom city

    Directory of Open Access Journals (Sweden)

    R. hajizadeh

    2014-02-01

    .Conclusion: Heat stress in almost all of the studied workplaces are higher than the recommended limits, and the outdoor workshops had the highest thermal stress, although heat stress did not show a significant correlation with the studied strains.

  13. Childhood Stress

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Childhood Stress KidsHealth / For Parents / Childhood Stress What's in this ... and feel stress to some degree. Sources of Stress Stress is a function of the demands placed ...

  14. Correlations among Stress Parameters, Meat and Carcass Quality Parameters in Pigs

    Directory of Open Access Journals (Sweden)

    Marija Dokmanovic

    2015-03-01

    Full Text Available Relationships among different stress parameters (lairage time and blood level of lactate and cortisol, meat quality parameters (initial and ultimate pH value, temperature, drip loss, sensory and instrumental colour, marbling and carcass quality parameters (degree of rigor mortis and skin damages, hot carcass weight, carcass fat thickness, meatiness were determined in pigs (n = 100 using Pearson correlations. After longer lairage, blood lactate (p<0.05 and degree of injuries (p<0.001 increased, meat became darker (p<0.001, while drip loss decreased (p<0.05. Higher lactate was associated with lower initial pH value (p<0.01, higher temperature (p<0.001 and skin blemishes score (p<0.05 and more developed rigor mortis (p<0.05, suggesting that lactate could be a predictor of both meat quality and the level of preslaughter stress. Cortisol affected carcass quality, so higher levels of cortisol were associated with increased hot carcass weight, carcass fat thickness on the back and at the sacrum and marbling, but also with decreased meatiness. The most important meat quality parameters (pH and temperature after 60 minutes deteriorated when blood lactate concentration was above 12 mmol/L.

  15. Observation of ultraslow stress release in silicon nitride films on CaF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Tianyi [School of Biomedical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1, Canada and Institute of Microelectronics, Chinese Academy of Science, Beijing 100029 (China); Deen, M. Jamal, E-mail: jamal@mcmaster.ca [Department of Electrical and Computer Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1, Canada and School of Biomedical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1 (Canada); Xu, Changqing; Fang, Qiyin [Department of Engineering Physics, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4L7 (Canada); Selvaganapathy, P. Ravi [Department of Mechanical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4L7 (Canada); Zhang, Haiying [Institute of Microelectronics, Chinese Academy of Science, Beijing 100029 (China)

    2015-07-15

    Silicon nitride thin films are deposited by plasma-enhanced chemical vapor deposition on (100) and (111) CaF{sub 2} crystalline substrates. Delaminated wavy buckles formed during the release of internal compressive stress in the films and the stress releasing processes are observed macroscopically and microscopically. The stress release patterns start from the substrate edges and propagate to the center along defined directions aligned with the crystallographic orientations of the substrate. The stress releasing velocity of SiN{sub x} film on (111) CaF{sub 2} is larger than that of SiN{sub x} film with the same thickness on (100) CaF{sub 2}. The velocities of SiN{sub x} film on both (100) and (111) CaF{sub 2} increase with the film thickness. The stress releasing process is initiated when the films are exposed to atmosphere, but it is not a chemical change from x-ray photoelectron spectroscopy.

  16. The Hispanic Stress Inventory Version 2: Improving the assessment of acculturation stress.

    Science.gov (United States)

    Cervantes, Richard C; Fisher, Dennis G; Padilla, Amado M; Napper, Lucy E

    2016-05-01

    This article reports on a 2-phase study to revise the Hispanic Stress Inventory (HSI; Cervantes, Padilla, & Salgado de Snyder, 1991). The necessity for a revised stress-assessment instrument was determined by demographic and political shifts affecting Latin American immigrants and later-generation Hispanics in the United States in the 2 decades since the development of the HSI. The data for the revision of the HSI (termed the HSI2) was collected at 4 sites: Los Angeles, El Paso, Miami, and Boston, and included 941 immigrants and 575 U.S.-born Hispanics and a diverse population of Hispanic subgroups. The immigrant version of the HSI2 includes 10 stress subscales, whereas the U.S.-born version includes 6 stress subscales. Both versions of the HSI2 are shown to possess satisfactory Cronbach's alpha reliabilities and demonstrate expert-based content validity, as well as concurrent validity when correlated with subscales of the Brief Symptom Inventory (Derogatis, 1993) and the Patient Health Questionnaire-9 (Kroenke, Spitzer, & Williams, 2001). The new HSI2 instruments are recommended for use by clinicians and researchers interested in assessing psychosocial stress among diverse Hispanic populations of various ethnic subgroups, age groups, and geographic location. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  17. [Association of occupational stress with quality of working life].

    Science.gov (United States)

    Zhang, Qin; Lan, Ya-Jia; Chen, Hong-Mei

    2011-07-01

    To assess occupational stress and quality of working life (QWL) and their association in workers with different jobs. The Occupational Stress Inventory Revised Edition (OSI-R) and Quality of Working Life Scale (QWL7-32) were administered to 194 workers in the Liaohe Oilfield. The association between occupational stress and quality of working life was analysed by controlling job types and other confounding variables. Office workers had significantly lower scores in occupational role questionnaire (ORQ) and personal strain questionnaire (PSQ) and higher scores in personal resources questionnaire (PRQ) and QWL than physical laborers (P<0.05). The PSQ scores were positively correlated with the ORQ scores and negatively correlated with the PRQ scores. The QWL scores were negatively correlated with the ORQ and PSQ scores, and positively correlated with the PRQ scores (P<0.001). The QWL scores changed with job types. The QWL scores declined with the increase of stress levels (P<0.01). ORQ, role boundary (RB), role insufficiency (RI), physical environment (PE), PSQ, vocational strain (VS), interpersonal strain (IS) and PRQ had a significant impact on quality of working life (P<0.01). Occupational stress is associated with quality of working life. Quality of working life can be improved through control of occupational stress.

  18. Bone stress in runners with tibial stress fracture.

    Science.gov (United States)

    Meardon, Stacey A; Willson, John D; Gries, Samantha R; Kernozek, Thomas W; Derrick, Timothy R

    2015-11-01

    Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied loads, in runners with stress fracture. 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α=0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior-posterior outer diameter of the tibia and the sagittal plane bending moment explained >80% of the variance in anterior and posterior bone stress. Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial-lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Oxidative Stress Correlates with Headache Symptoms in Fibromyalgia: Coenzyme Q10 Effect on Clinical Improvement

    Science.gov (United States)

    Cordero, Mario D.; Cano-García, Francisco Javier; Alcocer-Gómez, Elísabet; De Miguel, Manuel; Sánchez-Alcázar, José Antonio

    2012-01-01

    Background Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs) and its association to headache symptoms in FM patients. The effects of oral coenzyme Q10 (CoQ10) supplementation on biochemical markers and clinical improvement were also evaluated. Methods We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Headache Impact Test (HIT-6). Oxidative stress was determined by measuring CoQ10, catalase and lipid peroxidation (LPO) levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs. Results We found decreased CoQ10, catalase and ATP levels in BMCs from FM patients as compared to normal control (P<0.05 and P<0.001, respectively) We also found increased level of LPO in BMCs from FM patients as compared to normal control (P<0.001). Significant negative correlations between CoQ10 or catalase levels in BMCs and headache parameters were observed (r = −0.59, P<0.05; r = −0.68, P<0.05, respectively). Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05). Oral CoQ10 supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P<0.001). Discussion The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM. PMID:22532869

  20. Oxidative stress correlates with headache symptoms in fibromyalgia: coenzyme Q₁₀ effect on clinical improvement.

    Directory of Open Access Journals (Sweden)

    Mario D Cordero

    Full Text Available BACKGROUND: Fibromyalgia (FM is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs and its association to headache symptoms in FM patients. The effects of oral coenzyme Q(10 (CoQ(10 supplementation on biochemical markers and clinical improvement were also evaluated. METHODS: We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ, visual analogues scales (VAS, and the Headache Impact Test (HIT-6. Oxidative stress was determined by measuring CoQ(10, catalase and lipid peroxidation (LPO levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs. RESULTS: We found decreased CoQ(10, catalase and ATP levels in BMCs from FM patients as compared to normal control (P < 0.05 and P < 0.001, respectively We also found increased level of LPO in BMCs from FM patients as compared to normal control (P < 0.001. Significant negative correlations between CoQ(10 or catalase levels in BMCs and headache parameters were observed (r  = -0.59, P < 0.05; r  =  -0.68, P < 0.05, respectively. Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05. Oral CoQ(10 supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P < 0.001. DISCUSSION: The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM.

  1. Correlations of the glycemic variability with oxidative stress and erythrocytes membrane stability in patients with type 1 diabetes under intensive treatment.

    Science.gov (United States)

    Rodrigues, Ricardo; Alves de Medeiros, Luciana; Moreira Cunha, Lucas; da Silva Garrote-Filho, Mario; Bernardino Neto, Morun; Tannus Jorge, Paulo; Santos Resende, Elmiro; Penha-Silva, Nilson

    2018-02-07

    This study aimed to evaluate the correlations of glycemic variability with erythrocyte membrane stability parameters and oxidative stress markers in patients with DM1 under intensive treatment. 90 patients with DM1 and under intensive treatment of the disease were evaluated in relation to anthropometric indices, records of glycemic averages and parameters of glycemic variability, biochemical dosages (glucose, uric acid, lipidogram, glycated hemoglobin, microalbuminuria, creatinine and iron) reticulocyte count, erythrocyte membrane stability parameters and oxidative stress markers (thiobarbituric acid reactive substances, TBARS, and glutathione reductase, GR). Indicators of glycemic variability in the short and long term showed correlations with parameters of membrane stability and markers of oxidative stress (GR). In addition, the comparison of these same parameters between the subgroups consisting of quartiles of GV or glycemic control also showed significant differences. In the DM1 patients studied here, glycemic variability showed correlations with oxidative stress and erythrocyte membrane stability variables. This corroborates the hypothesis that glycemic fluctuations interfere with lipid peroxidation and cell membrane behavior, emphasizing its participation in mechanisms related to the development of chronic complications of diabetes. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material

    International Nuclear Information System (INIS)

    Chen, B.; Hu, J.N.; Wang, Y.Q.; Zhang, S.Y.; Van Petegem, S.; Cocks, A.C.F.; Smith, D.J.; Flewitt, P.E.J.

    2015-01-01

    The role of misfit stress in kinematic hardening under reversed straining of a Type 316H austenitic stainless steel has been investigated by using neutron diffraction combined with in situ deformation. Initial misfit stresses, often referred to an intergranular internal stresses, were created by the tensile pre-straining at high temperature. The misfit stresses at the length-scale of grain families, measured by neutron diffraction, were shown to be a function of the magnitude of the tensile pre-strain. The pre-strained specimens were further subjected to either continued (tensile) straining or reversed (compressive) straining at room temperature. In situ neutron diffraction measurements were undertaken to monitor the change of the misfit stresses during loading. The macroscopic stress–strain behaviour was used to derive isotropic and kinematic hardening stresses developed in the pre-strained specimens. Results show that the change of the transient softening stress towards a zero value is accompanied by a decrease in the change of the misfit stresses. A multi-scale self-consistent model has been developed to assist in understanding the measured change of the misfit stresses when subjecting the material to strain reversal. An important conclusion is that the origin of the kinematic hardening of Type 316H austenitic stainless steel arises from the misfit stress between grains

  3. Correlation of macroscopic osteoarthrotic changes and radiographic findings in the acromioclavicular joint

    International Nuclear Information System (INIS)

    Stenlund, B.; Marions, O.; Engstroem, K.F.; Goldie, I.; Soedersjukhuset, Stockholm; Karolinska Sjukhuset, Stockholm

    1988-01-01

    In a total of 108 acromioclavicular articulations from cadavers the osteoarthrotic changes were studied. The articulations were macroscopically and radiographically ranked according to their grade of osteoarthrosis. The two ranking lines were correlated statistically and showed a rank correlation of 0.741. In 38 articulations tomography was also carried out. These articulations were classified into five grades of osteoarthrosis and the macroscopic, conventional radiographic and tomographic gradings were compared. The correlation coefficient for tomography versus macroscopy was 0.714. Tomography versus standard radiography showed a correlation of 0.767 and standard radiography versus macroscopy a correlation of 0.841. The standard radiographic investigation reveals moderate and severe osteoarthrotic changes in the acromioclavicular joint but cannot depict smaller changes. Tomography does not seem to improve the specificity. There is a need for a better radiologic technique in the examination of the acromioclavicular joint. Radiography during some kind of loading might be a practical way of improving the specificity and make it possible to show early osteoarthrosis in the acromioclavicular articulation. (orig.)

  4. Correlation of macroscopic osteoarthrotic changes and radiographic findings in the acromioclavicular joint

    Energy Technology Data Exchange (ETDEWEB)

    Stenlund, B.; Marions, O.; Engstroem, K.F.; Goldie, I.

    In a total of 108 acromioclavicular articulations from cadavers the osteoarthrotic changes were studied. The articulations were macroscopically and radiographically ranked according to their grade of osteoarthrosis. The two ranking lines were correlated statistically and showed a rank correlation of 0.741. In 38 articulations tomography was also carried out. These articulations were classified into five grades of osteoarthrosis and the macroscopic, conventional radiographic and tomographic gradings were compared. The correlation coefficient for tomography versus macroscopy was 0.714. Tomography versus standard radiography showed a correlation of 0.767 and standard radiography versus macroscopy a correlation of 0.841. The standard radiographic investigation reveals moderate and severe osteoarthrotic changes in the acromioclavicular joint but cannot depict smaller changes. Tomography does not seem to improve the specificity. There is a need for a better radiologic technique in the examination of the acromioclavicular joint. Radiography during some kind of loading might be a practical way of improving the specificity and make it possible to show early osteoarthrosis in the acromioclavicular articulation.

  5. Social support, stress and the aging brain.

    Science.gov (United States)

    Sherman, Stephanie M; Cheng, Yen-Pi; Fingerman, Karen L; Schnyer, David M

    2016-07-01

    Social support benefits health and well-being in older individuals, however the mechanism remains poorly understood. One proposal, the stress-buffering hypothesis states social support 'buffers' the effects of stress on health. Alternatively, the main effect hypothesis suggests social support independently promotes health. We examined the combined association of social support and stress on the aging brain. Forty healthy older adults completed stress questionnaires, a social network interview and structural MRI to investigate the amygdala-medial prefrontal cortex circuitry, which is implicated in social and emotional processing and negatively affected by stress. Social support was positively correlated with right medial prefrontal cortical thickness while amygdala volume was negatively associated with social support and positively related to stress. We examined whether the association between social support and amygdala volume varied across stress level. Stress and social support uniquely contribute to amygdala volume, which is consistent with the health benefits of social support being independent of stress. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  6. Acute psychosocial stress and children's memory.

    Science.gov (United States)

    de Veld, Danielle M J; Riksen-Walraven, J Marianne; de Weerth, Carolina

    2014-07-01

    We investigated whether children's performance on working memory (WM) and delayed retrieval (DR) tasks decreased after stress exposure, and how physiological stress responses related to performance under stress. About 158 children (83 girls; Mage = 10.61 years, SD = 0.52) performed two WM tasks (WM forward and WM backward) and a DR memory task first during a control condition, and 1 week later during a stress challenge. Salivary alpha-amylase (sAA) and cortisol were assessed during the challenge. Only WM backward performance declined over conditions. Correlations between physiological stress responses and performance within the stress challenge were present only for WM forward and DR. For WM forward, higher cortisol responses were related to better performance. For DR, there was an inverted U-shape relation between cortisol responses and performance, as well as a cortisol × sAA interaction, with concurrent high or low responses related to optimal performance. This emphasizes the importance of including curvilinear and interaction effects when relating physiology to memory.

  7. Stress and coping among elderly African-Americans.

    Science.gov (United States)

    Holt-Hill, Shirley Ann

    2009-12-01

    The purpose of this descriptive correlation was to examine the relationship between the amount of psychological stress experienced and the methods of coping with stress among elderly African-Americans. Demographic variables (age, gender, marital status, education, and occupation), personal resources (health, religion, and social support), and the effects of perception of racial discrimination were included to determine the relationship among the variables and to predict the perceived amount ofpsychological stress and the methods of coping. Subjects were males and females, who were community dwellers, between 65 to 88 years of age. Each subject completed four questionnaires: a Demographic Personal Data Questionnaire, the Short Portable Mental Status Questionnaire, the Stokes/Gordon Stress Scale, and the Ways of Coping Questionnaire. The data were analyzed by computing measures of central tendency, frequency, percentile, and measures of variability. Correlation and stepwise regression were used for predictions and to test null hypotheses. The findings indicated that elderly African-Americans experienced psychologically stressful events in their lives such as concerns for the world, slowing down, physical limitation, financial concerns, and not enough time with their children and grandchildren.

  8. Mindfulness, perceived stress, and subjective well-being: a correlational study in primary care health professionals.

    Science.gov (United States)

    Atanes, Ana C M; Andreoni, Solange; Hirayama, Marcio S; Montero-Marin, Jesús; Barros, Viviam V; Ronzani, Telmo M; Kozasa, Eliza H; Soler, Joaquim; Cebolla, Ausiàs; Garcia-Campayo, Javier; Demarzo, Marcelo M P

    2015-09-02

    Primary health care professionals (PHPs) usually report high levels of distress and burnout symptoms related to job strain. Mindfulness, defined as non-judgmental-present-moment awareness, seems to be a moderator in the causal association between life stressors and well-being. This study aimed to verify correlations among self-reported mindfulness, perceived stress (PS), and subjective well-being (SW) in Brazilian PHPs. We performed a correlational cross-sectional study in a purposive sample of Brazilian PHPs (physicians, nurses, nursing assistants, and community health workers), working in community-oriented primary care programs (known locally as "Family Health Programs"). We used validated self-reporting instruments: the Mindful Attention Awareness Scale (MAAS), the Perceived Stress Scale (PSS), and the Subjective Well-being Scale (SWS). We performed a multivariate analysis of variance (MANOVA), through regression coefficients (beta) in relation to the professional category (nursing assistant), in addition to the length of time in the same job (under than 6 months) that had indicated the lowest level of PS. Participants (n=450) comprised community health workers (65.8%), nursing assistants (18%), registered nurses (10.0%), and doctors (family physicians) (6.0%); 94% were female and 83.1% had worked in the same position for more than one year. MANOVA regression analysis showed differences across professional categories and length of time in the same job position in relation to mindfulness, PS, and SW. Nurses demonstrated lower levels of mindfulness, higher PS, and SW negative affect, as well as lower SW positive affect. Being at work for 1 year or longer showed a clear association with higher PS and lower SW positive affect, and no significance with mindfulness levels. Pearson's coefficient values indicated strong negative correlations between mindfulness and PS, and medium correlations between mindfulness and SW. In this study, there were clear correlations

  9. Work-related stress and posttraumatic stress in emergency medical services.

    Science.gov (United States)

    Donnelly, Elizabeth

    2012-01-01

    Recent research efforts in emergency medical services (EMS) has identified variability in the ability of EMS personnel to recognize their level of stress-related impairment. Developing a better understanding of how workplace stress may affect EMS personnel is a key step in the process of increasing awareness of the impact of work-related stress and stress-related impairment. This paper demonstrates that for those in EMS, exposure to several types of workplace stressors is linked to stress reactions. Stress reactions such as posttraumatic stress symptomatology (PTSS) have the potential to negatively influence the health of EMS providers. This research demonstrates that two different types of work-related stress and alcohol use influence the development of PTSS. A probability sample of nationally registered emergency medical technician (EMT)-Basics and EMT-Paramedics (n = 1,633) completed an Internet-based survey. Respondents reported their levels of operational and organizational types of chronic stress, critical incident stress, alcohol use, and PTSS. Ordinary least squares regression illustrated that when demographic factors were controlled, organizational and operational forms of chronic stress, critical incident stress, and alcohol use were all significant predictors of PTSS (p stress and critical incident stress (p stress and alcohol use (p stress reaction. Higher levels of chronic stress, critical incident stress, and alcohol use significantly related to an increased level of PTSS. Further, for those reporting high levels of alcohol use or critical incident stress, interactions with high levels of chronic operational stress were associated with higher rates of PTSS. For those interested in the impact of work-related stress in EMS, these findings indicate that attention must be paid to levels of stress associated with both critical incident exposure as well as the chronic stress providers experience on a day-to-day basis.

  10. Forecasting Portfolio Risk in Normal and Stressed Markets

    OpenAIRE

    Bhansali, Vineer; Wise, Mark B.

    2001-01-01

    The instability of historical risk factor correlations renders their use in estimating portfolio risk extremely questionable. In periods of market stress correlations of risk factors have a tendency to quickly go well beyond estimated values. For instance, in times of severe market stress, one would expect with certainty to see the correlation of yield levels and credit spreads go to -1, even though historical estimates will miss this region of correlation. This event might lead to realized p...

  11. A constitutive equation for creep fracture under constant, variable or cyclic positive stress

    International Nuclear Information System (INIS)

    Snedden, J.D.

    1977-01-01

    Prediction of creep fracture of metals under variable stress is one of the most difficult problems of applied mechanics. At NEL this problem is under investigation using an approach in which creep is represented by two macroscopic components: an anelastic (reversible) component and a plastic (irreversible) component. Under variable loading conditions, the anelastic component's behaviour will be most important and, if an experimental programme is logically planned, the structural processes responsible will be implicit in the resulting constitutive equation describing the material's behaviour. The present paper deals with the development and application of a constitutive equation for creep fracture of RR58 Aluminium alloy at 180 0 C under variable stress and such a constitutive equation can be extrapolated to cover long-time behaviour just as with conventional constant stress creep fracture equations. Constant stress, in fact, is one of the boundary conditions of the general constitutive equation, representing zero prior damage. The other boundary condition is that of 'cadence loading' in which the stress is completely removed and then re-applied in a cyclic fashion. (Auth.)

  12. Bruxism affects stress responses in stressed rats.

    Science.gov (United States)

    Sato, Chikatoshi; Sato, Sadao; Takashina, Hirofumi; Ishii, Hidenori; Onozuka, Minoru; Sasaguri, Kenichi

    2010-04-01

    It has been proposed that suppression of stress-related emotional responses leads to the simultaneous activation of both sympathetic and parasympathetic divisions of the autonomic nervous system (ANS) and that the expression of these emotional states has a protective effect against ulcerogenesis. In the present study, we investigated whether stress-induced bruxism activity (SBA) has a physiological effect of on the stress-induced changes of the stomach, thymus, and spleen as well as blood leukocytes, cortisol, and adrenaline. This study demonstrated that SBA attenuated the stress-induced ulcer genesis as well as degenerative changes of thymus and spleen. SBA also attenuated increases of adrenaline, cortisol, and neutrophils in the blood. In conclusion, expression of aggression through SBA during stress exposure attenuates both stress-induced ANS response, including gastric ulcer formation.

  13. Stress/Rest Tc-99m-MIBI SPECT in Comparison with Rest/Stress Rubidium - 82 PET

    International Nuclear Information System (INIS)

    Lee, D. S.; Kamg, K. W.; Lee, K. H.; Jeong, J. M.; Kwark, C. E.; Chung, J. K.; Lee, M.C.; Seo, J. D.; Koh, C. S.

    1995-01-01

    We compared stress/rest myocardial Tc-99m-MIBI tomographic image findings with rest/stress rubidium-82 tomographic images. In 23 patients with coronary artery disease (12 of them received bypass grafts before) and 6 normal subjects, rest rubidium PET study was performed, rubidium-82 and Tc-99m-MIBI were injected simultaneously to each patient after dipyridamole stress for rubidium PET and MIBI SPECT; and rest MIBI SPECT was performed 4 hours thereafter. We scored segmental decrease of rubidium, or MIBI uptakes into 5 grades for 29 segments from 3 short-axis, vertical and horizontal slices. Scores were summed for each major arterial territory. When more score than two grade-2's or one grade-3 was considered as the cue for significant stenosis for major arterial territories, 67% of 46 stenosed arteries were found with MIBI studies and 78% of them by rubidium studies. Fourteen among 28 grafted arterial territories of 12 post-CABG patients were found normal with both rubidium and MIBI. Segmental scores were concordant between rubidium and MIBI in 72% of 709-stress segments and in 80% of 825 rest segments. Stress rubidium segmental scores were less than stress MIBI scores in 9%, so were rest rubidium scores. Stress rubidium scores were more than stress MIBI scores in 20% of segments, and rest rubidium segmental scores were more than rest MIBI scores in 11%. Rank correlations (Spearman's rho's more than 0.7(stress) and 0.5(rest), slopes (MIBI/rubidium) around 0.7(stress) and 0.9(rest) suggested deeper and wider defects in stress with rubidium. Slope over 1 (MIBI/rubidium) with LAD segmental scores at rest and 7 territories which had much larger score with MIBI revealed exaggeration of rest defects with rest MIBI in same-day stress/rest study. Difference scores (stress-rest for each territory) suggesting ischemia were larger with rubidium (slope of MIBI/rubidium around 0.45). As has been implied by animal or separate-day- human studies, these segmental analyses with

  14. Structural changes of the brain in relation to occupational stress.

    Science.gov (United States)

    Savic, Ivanka

    2015-06-01

    Despite mounting reports about the negative effects of chronic occupational stress on cognitive functions, it is still uncertain whether and how this type of stress is associated with cerebral changes. This issue was addressed in the present MRI study, in which cortical thickness (Cth) and subcortical volumes were compared between 40 subjects reporting symptoms of chronic occupational stress (38 ± 6 years) and 40 matched controls (36 ± 6 years). The degree of perceived stress was measured with Maslach Burnout Inventory. In stressed subjects, there was a significant thinning of the mesial frontal cortex. When investigating the correlation between age and Cth, the thinning effect of age was more pronounced in the stressed group in the frontal cortex. Furthermore, their amygdala volumes were bilaterally increased (P = 0.020 and P = 0.003), whereas their caudate volumes were reduced (P = 0.040), and accompanied by impaired fine motor function. The perceived stress correlated positively with the amygdala volumes (r = 0.44, P = 0.04; r = 0.43, P = 04). Occupational stress was found to be associated with cortical thinning as well as with selective changes of subcortical volumes, with behavioral correlates. The findings support the hypothesis that stress-related excitotoxicity might be an underlying mechanism, and that the described condition is a stress related illness. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Nuclear stress test

    Science.gov (United States)

    ... Persantine stress test; Thallium stress test; Stress test - nuclear; Adenosine stress test; Regadenoson stress test; CAD - nuclear stress; Coronary artery disease - nuclear stress; Angina - nuclear ...

  16. Analysis of rock stress and rock stress measurements with application to Aespoe HRL

    International Nuclear Information System (INIS)

    Lundholm, Beatrice

    2000-11-01

    The process of choosing a site for a nuclear waste repository means that many aspects have to be taken into consideration. One of these is that the repository has to be mechanically stable for a long time. The mechanical stability of the rock is very difficult to determine. One of several factors, which determine the mechanical stability, is the virgin state of stress. The thesis project consists of two parts. In the first part the state of stress at Aespoe Hard Rock Laboratory had to be defined. This was done based on earlier rock stress measurements conducted during the years 1988 to 1997. Two different measurement techniques have been used, hydraulic fracturing and overcoring. During the overcoring two types of cells have been used, CSIRO HI-cell and a cell developed by the Swedish State Power Board (SSPB). In the second part of the project, investigation of the correlation between the stress and geological structures are made using numerical modelling tools such as FLAC, UDEC and 3DEC. The rock stress measurements using the hydraulic fracturing gave orientations of the horizontal stress that coincide with earlier hydraulic fracturing measurements conducted in Scandinavia. The magnitudes of rock stresses are slightly lower than the earlier reported stress magnitudes for the Scandinavian part of the earth crust. The rock stresses obtained from the overcoring resulted in higher stresses than what was predicted by the hydraulic fracturing measurements. However, the orientation of the maximum horizontal stresses coincides well between the two techniques. The orientation is also more or less constant with respect to increasing depth. The state of stress at Aespoe is defined by using the results from the hydraulic fracturing and the measurements conducted by SSPB-cell. The measurements from the SSPB-cell are used since these have a Poisson's ratio that corresponds well with the uniaxial tests of rock samples and since the measurements have been done at a distance from

  17. The shape of change in perceived stress, negative affect, and stress sensitivity during mindfulness based stress reduction

    NARCIS (Netherlands)

    Snippe, E.; Dziak, J.J.; Lanza, S.T.; Nyklicek, I.; Wichers, M.

    2017-01-01

    Both daily stress and the tendency to react to stress with heightened levels of negative affect (i.e., stress sensitivity) are important vulnerability factors for adverse mental health outcomes. Mindfulness-based stress reduction (MBSR) may help to reduce perceived daily stress and stress

  18. The Shape of Change in Perceived Stress, Negative Affect, and Stress Sensitivity During Mindfulness-Based Stress Reduction

    NARCIS (Netherlands)

    Snippe, Evelien; Dziak, John J.; Lanza, Stephanie T.; Nykliek, Ivan; Wichers, Marieke

    Both daily stress and the tendency to react to stress with heightened levels of negative affect (i.e., stress sensitivity) are important vulnerability factors for adverse mental health outcomes. Mindfulness-based stress reduction (MBSR) may help to reduce perceived daily stress and stress

  19. THE CORRELATION BETWEEN LIPID PROFILE AND STRESS LEVELS IN PART CENTRAL IRAN: ISFAHAN HEALTHY HEART PROGRAM

    Directory of Open Access Journals (Sweden)

    Maryam Shahnam

    2010-12-01

    Full Text Available Abstract            Background: Previous studies suggest that mental status may influence serum lipid levels. This study was conducted on adult population living in rural and urban areas in Central Iran to assess the correlation between stress level and lipid profile disorders.Methods: Data was extracted from final evaluation of Isfahan Healthy Heart Program (IHHP in 2008. Multistage and random cluster methods were used for sampling. The study population consisted of 9752 adults aged ≥19 years living in three districts namely Isfahan, Arak and Najaf Abad. Demographic data, age and sex were recorded. Blood samples were taken to determine the lipid levels including total cholesterol (TC, low-density lipoprotein cholesterol (LDL-C, low levels of high-density lipoprotein cholesterol (HDL-C and triglycerides. Stress levels were assessed using the General Health Questionnaire. Logistic regression and chi-square tests were used for statistical analysis.Results: The odds ratios of high stress in individuals with high levels of TC, LDL-C and low levels of HDL-C compared to normal individuals after adjustment for age and sex were as follows respectively: 1.05 (1.02,1.15, 1.06 (1.02,1.18, 1.06 (1.01,1.17.Conclusion: Intervention activities towards reduction of stress levels at the community level may be useful as part of the strategy for cardiovascular disease prevention. Keywords: Cholesterol, Triglycerides, Stress, Questionnaire, Adult

  20. Impulsivity and its relationship with anxiety, depression and stress.

    Science.gov (United States)

    Moustafa, Ahmed A; Tindle, Richard; Frydecka, Dorota; Misiak, Błażej

    2017-04-01

    We aimed to assess the association between depression, anxiety, stress and impulsivity with respect to age. The Depression, Anxiety and Stress Scale (DASS-42) and the Barratt Impulsiveness Scale (BIS-11) were administered to 145 individuals. Due to a negative correlation between age, BIS-11 and DASS-42 subscales, participants were divided into three groups: young-aged (18-30years), middle-aged (31-49years) and old-aged (≥50years). Subjects from old-aged group had significantly lower scores of depression, anxiety, stress and impulsivity compared to those from younger groups. Anxiety, followed by stress and depression, was the strongest predictor of BIS-11 total score in young-aged and middle-aged individuals. There were no significant differences in the correlations between BIS-11 total score, depression, anxiety and stress in old-aged individuals. Our results indicate that the levels of depression, anxiety, stress and impulsivity decrease with age. Additionally, age might moderate the effect of depression, anxiety and stress on impulsivity. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Chronic stress disrupts neural coherence between cortico-limbic structures

    Directory of Open Access Journals (Sweden)

    João Filipe Oliveira

    2013-02-01

    Full Text Available Chronic stress impairs cognitive function, namely on tasks that rely on the integrity of cortico-limbic networks. To unravel the functional impact of progressive stress in cortico-limbic networks we measured neural activity and spectral coherences between the ventral hippocampus (vHIP and the medial prefrontal cortex (mPFC in rats subjected to short term (STS and chronic unpredictable stress (CUS. CUS exposure consistently disrupted the spectral coherence between both areas for a wide range of frequencies, whereas STS exposure failed to trigger such effect. The chronic stress-induced coherence decrease correlated inversely with the vHIP power spectrum, but not with the mPFC power spectrum, which supports the view that hippocampal dysfunction is the primary event after stress exposure. Importantly, we additionally show that the variations in vHIP-to-mPFC coherence and power spectrum in the vHIP correlated with stress-induced behavioral deficits in a spatial reference memory task. Altogether, these findings result in an innovative readout to measure, and follow, the functional events that underlie the stress-induced reference memory impairments.

  2. Stress and Protists: No life without stress.

    Science.gov (United States)

    Slaveykova, Vera; Sonntag, Bettina; Gutiérrez, Juan Carlos

    2016-08-01

    We report a summary of the symposium "Stress and Protists: No life without stress", which was held in September 2015 on the VII European Congress of Protistology in partnership with the International Society of Protistologists (Seville, Spain). We present an overview on general comments and concepts on cellular stress which can be also applied to any protist. Generally, various environmental stressors may induce similar cell responses in very different protists. Two main topics are reported in this manuscript: (i) metallic nanoparticles as environmental pollutants and stressors for aquatic protists, and (ii) ultraviolet radiation - induced stress and photoprotective strategies in ciliates. Model protists such as Chlamydomonas reinhardtii and Tetrahymena thermophila were used to assess stress caused by nanoparticles while stress caused by ultraviolet radiation was tested with free living planktonic ciliates as well as with the symbiont-bearing model ciliate Paramecium bursaria. For future studies, we suggest more intensive analyses on protist stress responses to specific environmental abiotic and/or biotic stressors at molecular and genetic levels up to ecological consequences and food web dynamics. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. Social stress contagion in rats: Behavioural, autonomic and neuroendocrine correlates.

    Science.gov (United States)

    Carnevali, Luca; Montano, Nicola; Statello, Rosario; Coudé, Gino; Vacondio, Federica; Rivara, Silvia; Ferrari, Pier Francesco; Sgoifo, Andrea

    2017-08-01

    The negative emotional consequences associated with life stress exposure in an individual can affect the emotional state of social partners. In this study, we describe an experimental rat model of social stress contagion and its effects on social behaviour and cardiac autonomic and neuroendocrine functions. Adult male Wistar rats were pair-housed and one animal (designated as "demonstrator" (DEM)) was submitted to either social defeat stress (STR) by an aggressive male Wild-type rat in a separate room or just exposed to an unfamiliar empty cage (control condition, CTR), once a day for 4 consecutive days. We evaluated the influence of cohabitation with a STR DEM on behavioural, cardiac autonomic and neuroendocrine outcomes in the cagemate (defined "observer" (OBS)). After repeated social stress, STR DEM rats showed clear signs of social avoidance when tested in a new social context compared to CTR DEM rats. Interestingly, also their cagemate STR OBSs showed higher levels of social avoidance compared to CTR OBSs. Moreover, STR OBS rats exhibited a higher heart rate and a larger shift of cardiac autonomic balance toward sympathetic prevalence (as indexed by heart rate variability analysis) immediately after the first reunification with their STR DEMs, compared to the control condition. This heightened cardiac autonomic responsiveness habituated over time. Finally, STR OBSs showed elevated plasma corticosterone levels at the end of the experimental protocol compared to CTR OBSs. These findings demonstrate that cohabitation with a DEM rat, which has experienced repeated social defeat stress, substantially disrupts social behaviour and induces short-lasting cardiac autonomic activation and hypothalamic-pituitary-adrenal axis hyperactivity in the OBS rat, thus suggesting emotional state-matching between the OBS and the DEM rats. We conclude that this rodent model may be further exploited for investigating the neurobiological bases of negative affective sharing between

  4. Oxidative stress negatively affects human sperm mitochondrial respiration.

    Science.gov (United States)

    Ferramosca, Alessandra; Pinto Provenzano, Sara; Montagna, Daniela Domenica; Coppola, Lamberto; Zara, Vincenzo

    2013-07-01

    To correlate the level of oxidative stress in serum and seminal fluid and the level of sperm deoxyribonucleic acid (DNA) fragmentation with sperm mitochondrial respiratory efficiency. Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. A possible relationship between sperm mitochondrial respiratory efficiency, the level of oxidative stress, and the level of sperm DNA fragmentation was investigated. Sperm motility was positively correlated with mitochondrial respiration but negatively correlated with oxidative stress and DNA fragmentation. Interestingly, sperm mitochondrial respiratory activity was negatively affected by oxidative stress and DNA fragmentation. Our data indicate that sperm mitochondrial respiration is decreased in patients with high levels of reactive oxygen species by an uncoupling between electron transport and adenosine triphosphate synthesis. This reduction in mitochondrial functionality might be 1 of the reasons responsible for the decrease in spermatozoa motility. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. X-ray diffraction study of stress relaxation in cubic boron nitride films grown with simultaneous medium-energy ion bombardment

    International Nuclear Information System (INIS)

    Abendroth, B.; Gago, R.; Eichhorn, F.; Moeller, W.

    2004-01-01

    Relaxation of the intrinsic stress of cubic boron nitride (cBN) thin films has been studied by x-ray diffraction (XRD) using synchrotron light. The stress relaxation has been attained by simultaneous medium-energy ion bombardment (2-10 keV) during magnetron sputter deposition, and was confirmed macroscopically by substrate curvature measurements. In order to investigate the stress-release mechanisms, XRD measurements were performed in in-plane and out-of-plane geometry. The analysis shows a pronounced biaxial state of compressive stress in the cBN films grown without medium-energy ion bombardment. This stress is partially released during the medium-energy ion bombardment. It is suggested that the main path for stress relaxation is the elimination of strain within the cBN grains due to annealing of interstitials

  6. Oxidative stress adaptation with acute, chronic, and repeated stress.

    Science.gov (United States)

    Pickering, Andrew M; Vojtovich, Lesya; Tower, John; A Davies, Kelvin J

    2013-02-01

    Oxidative stress adaptation, or hormesis, is an important mechanism by which cells and organisms respond to, and cope with, environmental and physiological shifts in the level of oxidative stress. Most studies of oxidative stress adaption have been limited to adaptation induced by acute stress. In contrast, many if not most environmental and physiological stresses are either repeated or chronic. In this study we find that both cultured mammalian cells and the fruit fly Drosophila melanogaster are capable of adapting to chronic or repeated stress by upregulating protective systems, such as their proteasomal proteolytic capacity to remove oxidized proteins. Repeated stress adaptation resulted in significant extension of adaptive responses. Repeated stresses must occur at sufficiently long intervals, however (12-h or more for MEF cells and 7 days or more for flies), for adaptation to be successful, and the levels of both repeated and chronic stress must be lower than is optimal for adaptation to acute stress. Regrettably, regimens of adaptation to both repeated and chronic stress that were successful for short-term survival in Drosophila nevertheless also caused significant reductions in life span for the flies. Thus, although both repeated and chronic stress can be tolerated, they may result in a shorter life. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Gut microbiota composition is correlated to grid floor induced stress and behavior in the BALB/c mouse

    DEFF Research Database (Denmark)

    Bendtsen, Katja Maria Bangsgaard; Krych, Lukasz; Sørensen, Dorte Bratbo

    2012-01-01

    to grid floor. Stressing the mice clearly changed the cecal microbiota as determined by both DGGE and pyrosequencing. Odoribacter, Alistipes and an unclassified genus from the Coriobacteriaceae family increased significantly in the grid floor housed mice. Compared to baseline, the mice exposed to grid......Stress has profound influence on the gastro-intestinal tract, the immune system and the behavior of the animal. In this study, the correlation between gut microbiota composition determined by Denaturing Grade Gel Electrophoresis (DGGE) and tag-encoded 16S rRNA gene amplicon pyrosequencing (454/FLX......) and behavior in the Tripletest (Elevated Plus Maze, Light/Dark Box, and Open Field combined), the Tail Suspension Test, and Burrowing in 28 female BALB/c mice exposed to two weeks of grid floor induced stress was investigated. Cytokine and glucose levels were measured at baseline, during and after exposure...

  8. Stress in medical students.

    Science.gov (United States)

    Nechita, Florina; Nechita, Dan; Pîrlog, Mihail Cristian; Rogoveanu, Ion

    2014-01-01

    Stress has been defined as the state of a body threatened by imbalance under the influence of agents or conditions endangering its homeostatic mechanisms but the concept have multiple meanings in correlation with the origin and biological support of its effects. Also, stressors are multiple, recording one of the highest levels during the academic studies. For the medical students, stress represents an important challenge, especially during the first year of medical school, caused by the absence of a learning strategy, the sleepless night before the exam and also an unhealthy food intake during the exams. The coping strategies are important, their background being represented by the social support, especially within the family, and emotional, the passions of the medicine students being the most important stress-combating factor. Gender represents also an important factor for the stress vulnerability, manifested through medical and psychiatric symptoms. In order to train good doctors, fair and above all healthy, it is important to consider not only the information we want to transmit, but also the context in which we educate.

  9. The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

    Science.gov (United States)

    Hardebeck, Jeanne L.

    2014-01-01

    The focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to stress and changes in stress. The main shock static stress changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static stress change and changing the spatial distribution of seismicity to favor locations where the static stress change aligns with the background stress. The aftershock focal mechanisms are significantly aligned with the static stress changes for absolute stress changes of ≥ 0.02 MPa, for up to ~20 years following the main shock. The dynamic stress changes have similar, although smaller, effects on the local focal mechanisms and the spatial seismicity distribution. Dynamic stress effects are best observed at long periods (30–60 s) and for metrics based on repeated stress cycling in the same direction. This implies that dynamic triggering operates, at least in part, through cyclic shear stress loading in the direction of fault slip. The background stress also strongly controls both the preshock and aftershock mechanisms. While most aftershock mechanisms are well oriented in the background stress field, 10% of aftershocks are identified as poorly oriented outliers, which may indicate limited heterogeneity in the postmain shock stress field. The fault plane orientations of the outliers are well oriented in the background stress, while their slip directions are not, implying that the background stress restricts the distribution of available fault planes.

  10. Correlation functions of the chiral stress-tensor multiplet in $ \\mathcal{N}=4 $ SYM

    CERN Document Server

    Chicherin, Dmitry; Eden, Burkhard; Heslop, Paul; Korchemsky, Gregory P.; Mason, Lionel; Sokatchev, Emery

    2015-01-01

    We give a new method for computing the correlation functions of the chiral part of the stress-tensor supermultiplet that relies on the reformulation of N=4 SYM in twistor space. It yields the correlation functions in the Born approximation as a sum of Feynman diagrams on twistor space that involve only propagators and no integration vertices. We use this unusual feature of the twistor Feynman rules to compute the correlation functions in terms of simple building blocks which we identify as a new class of N=4 off-shell superconformal invariants. Making use of the duality between correlation functions and planar scattering amplitudes, we demonstrate that these invariants represent an off-shell generalisation of the on-shell invariants defining tree-level scattering amplitudes in N=4 SYM.

  11. Correlating yeast cell stress physiology to changes in the cell surface morphology: atomic force microscopic studies.

    Science.gov (United States)

    Canetta, Elisabetta; Walker, Graeme M; Adya, Ashok K

    2006-07-06

    Atomic Force Microscopy (AFM) has emerged as a powerful biophysical tool in biotechnology and medicine to investigate the morphological, physical, and mechanical properties of yeasts and other biological systems. However, properties such as, yeasts' response to environmental stresses, metabolic activities of pathogenic yeasts, cell-cell/cell-substrate adhesion, and cell-flocculation have rarely been investigated so far by using biophysical tools. Our recent results obtained by AFM on one strain each of Saccharomyces cerevisiae and Schizosaccharomyces pombe show a clear correlation between the physiology of environmentally stressed yeasts and the changes in their surface morphology. The future directions of the AFM related techniques in relation to yeasts are also discussed.

  12. Prevalence and correlates of increased lung/heart ratio of thallium-201 during dipyridamole stress imaging for suspected coronary artery disease

    International Nuclear Information System (INIS)

    Villanueva, F.S.; Kaul, S.; Smith, W.H.; Watson, D.D.; Varma, S.K.; Beller, G.A.

    1990-01-01

    There is little information concerning the prevalence and clinical correlates of increased pulmonary thallium-201 uptake during dipyridamole thallium-201 stress imaging. Accordingly, the clinical characteristics and quantitative thallium-201 findings were correlated with quantitative lung/heart thallium-201 ratio in 87 patients undergoing dipyridamole thallium-201 stress testing. Nineteen patients (22%) had an elevated ratio (greater than 0.51). These patients were more likely to have had an infarction, to be taking beta blockers, and have a lower rate-pressure product after dipyridamole administration than those with a normal ratio (p less than 0.03). An elevated ratio was associated with a greater likelihood of initial, redistribution and persistent defects, as well as left ventricular cavity dilatation on thallium-201 imaging (p less than 0.05). In addition, the number of myocardial segments demonstrating initial, redistribution and persistent defects was also greater in patients with increased ratios (p less than 0.03). Multivariate analysis demonstrated that the presence of redistribution and left ventricular cavity dilatation were the most significant correlates of lung/heart thallium-201 ratio. It is concluded that the prevalence of increased lung/heart thallium-201 ratio with dipyridamole thallium-201 stress imaging is similar to that seen with exercise stress imaging. As with exercise thallium-201 imaging, increased pulmonary thallium-201 uptake may be a marker of functionally more significant coronary artery disease

  13. Stress-assisted crystallisation in anodic titania

    International Nuclear Information System (INIS)

    Vanhumbeeck, Jean-Francois; Tian He; Schryvers, Dominique; Proost, Joris

    2011-01-01

    Research highlights: → Correlations between microstructure and internal stress during Ti anodising are established. → Large internal compressive stresses are accumulated in the film during anodising upto 12 V. →A transition from compressive to tensile stress is observed when the cell voltage exceeds 12 V. → At 40 V, the oxide films consist of two regions with different compositions and microstructures. Crystallisation of amorphous to anatase TiO 2 contributes to the compressive stress relaxation. - Abstract: The relationship between the microstructural and internal stress evolution during Ti anodising is discussed. Samples anodised galvanostatically to 12 V and 40 V, corresponding to different stages of the internal stress evolution, were examined by in-plane and cross-section transmission electron microscopy. Electron diffraction patterns have been complemented with stoichiometry data obtained from energy loss near edge structure spectra. The sample anodised to 40 V was observed to consist of two regions, with a crystallised inner region adjacent to the metal/oxide interface. Crystallisation of this region is associated with the presence of large compressive internal stresses which build up during anodising up to 12 V.

  14. Manage Stress

    Science.gov (United States)

    ... Manage Stress Print This Topic En español Manage Stress Browse Sections The Basics Overview Signs and Health ... and Health Effects What are the signs of stress? When people are under stress, they may feel: ...

  15. Neuroplastic Correlates in the mPFC Underlying the Impairment of Stress-Coping Ability and Cognitive Flexibility in Adult Rats Exposed to Chronic Mild Stress during Adolescence

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-01-01

    Full Text Available Using a valid chronic mild stress (CMS model of depression, we found that adolescent (postnatal days [PND] 28–41 CMS induced transient alterations in anhedonia that did not persist into adulthood after a 3-week recovery period. Previously stressed adult rats exhibited more immobility/despair behaviors in the forced swimming test and a greater number of trials to reach criterion in the set-shifting task, suggesting the impaired ability to cope with stressors and the cognitive flexibility that allows adaptation to dynamic environments during adulthood. In addition, adult rat exposure to adolescent CMS had a relatively inhibited activation in ERK signaling and downstream protein expression of phosphorylated cAMP-response element-binding protein (CREB and brain-derived neurotrophic factor (BDNF in the medial prefrontal cortex. Further correlation analysis demonstrated that immobility and set-shifting performance were positively correlated with the inhibition of ERK signaling. These results indicated adolescent CMS can be used as an effective stressor to model an increased predisposition to adult depression.

  16. Diffraction stress analysis of thin films; investigating elastic grain interaction

    International Nuclear Information System (INIS)

    Kumar, A.

    2005-12-01

    This work is dedicated to the investigation of specimens exhibiting anisotropic microstructures (and thus macroscopic elastic anisotropy) and/or inhomogeneous microstructures, as met near surfaces and in textured materials. The following aspects are covered: (i) Analysis of specimens with direction-dependent (anisotropic) elastic grain-interaction. Elastic grain-interaction determines the distribution of stresses and strains over the (crystallographically) differently oriented grains of a mechanically stressed polycrystal and the mechanical and diffraction (X-ray) elastic constants (relating (diffraction) lattice strains to mechanical stresses). Grain interaction models that allow for anisotropic, direction-dependent grain interaction have been developed very recently. The notion 'direction-dependent' grain-interaction signifies that different grain-interaction constraints prevail along different directions in a specimen. Practical examples of direction-dependent grain interaction are the occurrence of surface anisotropy in thin films and the surface regions of bulk polycrystals and the occurrence of grain-shape (morphological) texture. In this work, for the first time, stress analyses of thin films have been performed on the basis of these newly developed grain-interaction models. It has also been demonstrated that the identification of the (dominant) source of direction-dependent grain interaction is possible. The results for the grain interaction have been discussed in the light of microstructural investigations of the specimens by microscopic techniques. (ii) Analysis of specimens with depth gradients: Diffraction stress analysis can be hindered if gradients of the stress state, the composition or the microstructure occur in the specimen under investigation, as the so-called information depth varies in the course of a traditional stress measurement: Ambiguous results are thus generally obtained. In this work, a strategy for stress measurements at fixed

  17. The Community Child Health Network Life Stress Interview: a brief chronic stress measure for community health research.

    Science.gov (United States)

    Tanner Stapleton, Lynlee R; Dunkel Schetter, Christine; Dooley, Larissa N; Guardino, Christine M; Huynh, Jan; Paek, Cynthia; Clark-Kauffman, Elizabeth; Schafer, Peter; Woolard, Richard; Lanzi, Robin Gaines

    2016-07-01

    Chronic stress is implicated in many theories as a contributor to a wide range of physical and mental health problems. The current study describes the development of a chronic stress measure that was based on the UCLA Life Stress Interview (LSI) and adapted in collaboration with community partners for use in a large community health study of low-income, ethnically diverse parents of infants in the USA (Community Child Health Network [CCHN]). We describe the instrument, its purpose and adaptations, implementation, and results of a reliability study in a subsample of the larger study cohort. Interviews with 272 mothers were included in the present study. Chronic stress was assessed using the CCHN LSI, an instrument designed for administration by trained community interviewers to assess four domains of chronic stress, each rated by interviewers. Significant correlations ranging from small to moderate in size between chronic stress scores on this measure, other measures of stress, biomarkers of allostatic load, and mental health provide initial evidence of construct and concurrent validity. Reliability data for interviewer ratings are also provided. This relatively brief interview (15 minutes) is available for use and may be a valuable tool for researchers seeking to measure chronic stress reliably and validly in future studies with time constraints.

  18. Polyamine biosynthesis in rice cultivars under salt stress and comparison with observations under drought stress

    Directory of Open Access Journals (Sweden)

    Phuc Thi Do

    2014-05-01

    Full Text Available Soil salinity affects a large proportion of rural area and limits agricultural productivity. To investigate differential adaptation to soil salinity, we studied salt tolerance of 18 varieties of Oryza sativa using a hydroponic culture system. Based on visual inspection and photosynthetic parameters, cultivars were classified according to their tolerance level. Additionally, biomass parameters were correlated with salt tolerance. Polyamines have frequently been demonstrated to be involved in plant stress responses and therefore soluble leaf polyamines were measured. Under salinity, putrescine (Put content was unchanged or increased in tolerant, while dropped in sensitive cultivars. Spermidine (Spd content was unchanged at lower NaCl concentrations in all, while reduced at 100 mM NaCl in sensitive cultivars. Spermine (Spm content was increased in all cultivars. A comparison with data from 21 cultivars under long-term, moderate drought stress revealed an increase of Spm under both stress conditions. While Spm became the most prominent polyamine under drought, levels of all three polyamines were relatively similar under salt stress. Put levels were reduced under both, drought and salt stress, while changes in Spd were different under drought (decrease or salt (unchanged conditions. Regulation of polyamine metabolism at the transcript level during exposure to salinity was studied for genes encoding enzymes involved in the biosynthesis of polyamines and compared to expression under drought stress. Based on expression profiles, investigated genes were divided into generally stress-induced genes (ADC2, SPD/SPM2, SPD/SPM3, one generally stress-repressed gene (ADC1, constitutively expressed genes (CPA1, CPA2, CPA4, SAMDC1, SPD/SPM1, specifically drought-induced genes (SAMDC2, AIH, one specifically drought-repressed gene (CPA3 and one specifically salt-stress repressed gene (SAMDC4, revealing both overlapping and specific stress responses under these

  19. Modeling Macroscopic Shape Distortions during Sintering of Multi-layers

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye

    as to help achieve defect free multi-layer components. The initial thickness ratio between the layers making the multi-layer has also significant effect on the extent of camber evolution depending on the material systems. During sintering of tubular bi-layer structures, tangential (hoop) stresses are very...... large compared to radial stresses. The maximum value of hoop stress, which can generate processing defects such as cracks and coating peel-offs, occurs at the beginning of the sintering cycle. Unlike most of the models defining material properties based on porosity and grain size only, the multi...... (firing). However, unintended features like shape instabilities of samples, cracks or delamination of layers may arise during sintering of multi-layer composites. Among these defects, macroscopic shape distortions in the samples can cause problems in the assembly or performance of the final component...

  20. Correlation Between Posttraumatic Growth and Posttraumatic Stress Disorder Symptoms Based on Pearson Correlation Coefficient: A Meta-Analysis.

    Science.gov (United States)

    Liu, An-Nuo; Wang, Lu-Lu; Li, Hui-Ping; Gong, Juan; Liu, Xiao-Hong

    2017-05-01

    The literature on posttraumatic growth (PTG) is burgeoning, with the inconsistencies in the literature of the relationship between PTG and posttraumatic stress disorder (PTSD) symptoms becoming a focal point of attention. Thus, this meta-analysis aims to explore the relationship between PTG and PTSD symptoms through the Pearson correlation coefficient. A systematic search of the literature from January 1996 to November 2015 was completed. We retrieved reports on 63 studies that involved 26,951 patients. The weighted correlation coefficient revealed an effect size of 0.22 with a 95% confidence interval of 0.18 to 0.25. Meta-analysis provides evidence that PTG may be positively correlated with PTSD symptoms and that this correlation may be modified by age, trauma type, and time since trauma. Accordingly, people with high levels of PTG should not be ignored, but rather, they should continue to receive help to alleviate their PTSD symptoms.

  1. Morphological and Stress Vulnerability Indices for Human Coronary Plaques and Their Correlations with Cap Thickness and Lipid Percent: An IVUS-Based Fluid-Structure Interaction Multi-patient Study.

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2015-12-01

    Full Text Available Plaque vulnerability, defined as the likelihood that a plaque would rupture, is difficult to quantify due to lack of in vivo plaque rupture data. Morphological and stress-based plaque vulnerability indices were introduced as alternatives to obtain quantitative vulnerability assessment. Correlations between these indices and key plaque features were investigated. In vivo intravascular ultrasound (IVUS data were acquired from 14 patients and IVUS-based 3D fluid-structure interaction (FSI coronary plaque models with cyclic bending were constructed to obtain plaque wall stress/strain and flow shear stress for analysis. For the 617 slices from the 14 patients, lipid percentage, min cap thickness, critical plaque wall stress (CPWS, strain (CPWSn and flow shear stress (CFSS were recorded, and cap index, lipid index and morphological index were assigned to each slice using methods consistent with American Heart Association (AHA plaque classification schemes. A stress index was introduced based on CPWS. Linear Mixed-Effects (LME models were used to analyze the correlations between the mechanical and morphological indices and key morphological factors associated with plaque rupture. Our results indicated that for all 617 slices, CPWS correlated with min cap thickness, cap index, morphological index with r = -0.6414, 0.7852, and 0.7411 respectively (p<0.0001. The correlation between CPWS and lipid percentage, lipid index were weaker (r = 0.2445, r = 0.2338, p<0.0001. Stress index correlated with cap index, lipid index, morphological index positively with r = 0.8185, 0.3067, and 0.7715, respectively, all with p<0.0001. For all 617 slices, the stress index has 66.77% agreement with morphological index. Morphological and stress indices may serve as quantitative plaque vulnerability assessment supported by their strong correlations with morphological features associated with plaque rupture. Differences between the two indices may lead to better plaque

  2. Modulation of attentional inhibition by norepinephrine and cortisol after psychological stress.

    Science.gov (United States)

    Skosnik, P D; Chatterton, R T; Swisher, T; Park, S

    2000-04-01

    Two of the most salient physiological responses to stress are increased norepinephrine (NE) and cortisol (CORT) activities. However, it is unclear how these neurochemical events affect cognition, especially attention. We examined the effects of mild psychological stress on selective attention, as assessed by the negative priming (NP) paradigm. Salivary measures of the stress hormone CORT and alpha-amylase (a correlate of NE) were assayed to probe the relationship between the stress response and attentional inhibition. Healthy subjects (N = 20) engaged in the attention task, which was then followed by 15 min of a stressful video game before a return to the attentional task. Baseline saliva samples were obtained before the experiment began, 1 min after the video-game stressor, and 20 min post-stress. Subjects showed a significant reduction in NP and a decrease in reaction time (RT) after the video game. Moreover, alpha-amylase levels increased significantly after the stressor, indicating the role of NE in the acute stress response. While CORT levels remained unchanged after stress, CORT correlated significantly with both NP scores and RT after the stressor. These results imply that mild psychological stress can significantly alter attentional processes. Given the increase in alpha-amylase and the correlation between attention and CORT after stress, it seems likely that attentional processes are under tight control by brain systems which mediate the fight-or-flight response.

  3. Triathletes Lose Their Advantageous Pain Modulation under Acute Psychosocial Stress.

    Science.gov (United States)

    Geva, Nirit; Pruessner, Jens; Defrin, Ruth

    2017-02-01

    Triathletes, who constantly engage in intensely stressful sport, were recently found to exhibit greater pain tolerance and more efficient pain inhibition capabilities than nonathletes. However, pain inhibition correlated negatively with retrospective reports of mental stress during training and competition. The aim of the current study was to test pain inhibition capabilities of triathletes under acute, controlled psychological stress manipulation. Participants were 25 triathletes and ironman triathletes who underwent the measurement of pain threshold, pain intolerance, tonic suprathreshold pain, and conditioned pain modulation before and during exposure to the Montreal Imaging Stress Task (MIST). Perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol levels were obtained as indices of stress. The MIST induced a significant stress reaction manifested in the subjective and objective indices. Overall, a significant reduction in pain threshold and in conditioned pain modulation efficacy was observed after the MIST, which reached the baseline levels observed previously in nonathletes. Paradoxically, the magnitude of this stress-induced hyperalgesia (SIH) correlated negatively with the magnitude of the stress response; low-stress responders exhibited greater SIH than high-stress responders. The results suggest that under acute psychological stress, triathletes not only react with SIH and a reduction in pain modulation but also lose their advantageous pain modulation over nonathletes. The stronger the stress response recorded, the weaker the SIH. It appears that triathletes are not resilient to stress, responding with an increase in the sensitivity to pain as well as a decrease in pain inhibition. The possible effects of athletes' baseline pain profile and stress reactivity on SIH are discussed.

  4. [Nursery Teacher's Stress Scale (NTSS): reliability and validity].

    Science.gov (United States)

    Akada, Taro

    2010-06-01

    This study describes the development and evaluation of the Nursery Teacher's Stress Scale (NTSS), which explores the relation between daily hassles at work and work-related stress. In Analysis 1, 29 items were chosen to construct the NTSS. Six factors were identified: I. Stress relating to child care; II. Stress from human relations at work; III. Stress from staff-parent relations; IV. Stress from lack of time; V. Stress relating to compensation; and VI. Stress from the difference between individual beliefs and school policy. All these factors had high degrees of internal consistency. In Analysis 2, the concurrent validity of the NTSS was examined. The results showed that the NTSS total scores were significantly correlated with the Job Stress Scale-Revised Version (job stressor scale, r = .68), the Pre-school Teacher-efficacy Scale (r = -.21), and the WHO-five Well-Being Index Japanese Version (r = -.40). Work stresses are affected by several daily hassles at work. The NTSS has acceptable reliability and validity, and can be used to improve nursery teacher's mental health.

  5. Perceived stress and fatigue among students in a doctor of chiropractic training program.

    Science.gov (United States)

    Kizhakkeveettil, Anupama; Vosko, Andrew M; Brash, Marissa; Ph, Dr; Philips, Michael A

    2017-03-01

    High levels of stress and fatigue are associated with decreased academic success, well-being, and quality of life. The objective of this research was to quantify levels of perceived stress and fatigue among chiropractic students to identify sources of and student coping mechanisms for perceived stress and fatigue and to identify the relationship between students' perceived stress and fatigue. A survey comprised of the Perceived Stress Scale, the Undergraduate Sources of Stress Survey, and the Piper Fatigue Scale was administered to chiropractic students in their 2nd, 5th, and 8th trimesters of doctoral study. Data were analyzed by descriptive statistics, 1-way analysis of variance, and linear correlation tests. Students reported having moderate to high levels of stress and fatigue, with higher levels of stress and fatigue seen in women than in men. A nonsignificant difference among stress scores and a significant difference among fatigue scores were observed based on program term. Levels of stress predicted levels of fatigue, and stress was strongly correlated with psychological health, relationships with family members, mood, and need for learning accommodations. Fatigue was strongly correlated with psychological health, academic demands, and conflicts between studies and other activities. There are differences in the reporting of perceived stress and fatigue levels in this chiropractic student population based on gender. The correlation between fatigue and stress also suggests that measures that may alleviate one may likely affect the other.

  6. Stress Incontinence

    Science.gov (United States)

    Stress incontinence Overview Urinary incontinence is the unintentional loss of urine. Stress incontinence happens when physical movement or activity — such ... coughing, sneezing, running or heavy lifting — puts pressure (stress) on your bladder. Stress incontinence is not related ...

  7. Work related stress and blood glucose levels.

    Science.gov (United States)

    Sancini, A; Ricci, S; Tomei, F; Sacco, C; Pacchiarotti, A; Nardone, N; Ricci, P; Suppi, A; De Cesare, D P; Anzelmo, V; Giubilati, R; Pimpinella, B; Rosati, M V; Tomei, G

    2017-01-01

    The aim of the study is to evaluate work-related subjective stress in a group of workers on a major Italian company in the field of healthcare through the administration of a valid "questionnaire-tool indicator" (HSE Indicator Tool), and to analyze any correlation between stress levels taken from questionnaire scores and blood glucose values. We studied a final sample consisting of 241 subjects with different tasks. The HSE questionnaire - made up of 35 items (divided into 7 organizational dimensions) with 5 possible answers - has been distributed to all the subjects in occasion of the health surveillance examinations provided by law. The questionnaire was then analyzed using its specific software to process the results related to the 7 dimensions. These results were compared using the Pearson correlation and multiple linear regression with the blood glucose values obtained from each subject. From the analysis of the data the following areas resulted critical, in other words linked to an intermediate (yellow area) or high (red area) condition of stress: sustain from managers, sustain from colleagues, quality of relationships and professional changes. A significant positive correlation (p work stress can be statistically associated with increased levels of blood glucose.

  8. Thermomechanical macroscopic model of shape memory alloys

    International Nuclear Information System (INIS)

    Volkov, A.E.; Sakharov, V.Yu.

    2003-01-01

    The phenomenological macroscopic model of the mechanical behaviour of the titanium nickelide-type shape memory alloys is proposed. The model contains as a parameter the average phase shear deformation accompanying the martensite formation. It makes i possible to describe correctly a number of functional properties of the shape memory alloys, in particular, the pseudoelasticity ferroplasticity, plasticity transformation and shape memory effects in the stressed and unstressed samples [ru

  9. Stress Management

    Science.gov (United States)

    Healthy Lifestyle Stress management By Mayo Clinic Staff Stress basics Stress is a normal psychological and physical reaction to the demands of life. ... some people's alarm systems rarely shut off. Stress management gives you a range of tools to reset ...

  10. Prenatal Maternal Stress Programs Infant Stress Regulation

    Science.gov (United States)

    Davis, Elysia Poggi; Glynn, Laura M.; Waffarn, Feizal; Sandman, Curt A.

    2011-01-01

    Objective: Prenatal exposure to inappropriate levels of glucocorticoids (GCs) and maternal stress are putative mechanisms for the fetal programming of later health outcomes. The current investigation examined the influence of prenatal maternal cortisol and maternal psychosocial stress on infant physiological and behavioral responses to stress.…

  11. High stresses stored in fault zones: example of the Nojima fault (Japan)

    Science.gov (United States)

    Boullier, Anne-Marie; Robach, Odile; Ildefonse, Benoît; Barou, Fabrice; Mainprice, David; Ohtani, Tomoyuki; Fujimoto, Koichiro

    2018-04-01

    During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan) that was drilled after the Hyogo-ken Nanbu (Kobe) earthquake is studied by using electron backscattered diffraction (EBSD) and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7-11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to the peak strength of a

  12. High stresses stored in fault zones: example of the Nojima fault (Japan

    Directory of Open Access Journals (Sweden)

    A.-M. Boullier

    2018-04-01

    Full Text Available During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan that was drilled after the Hyogo-ken Nanbu (Kobe earthquake is studied by using electron backscattered diffraction (EBSD and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7–11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to

  13. Evaluation of the Correlations between Depression, Anxiety, and Stress as DASS-21 Subscales and High-Risk Behaviors in the Adolescents in Torghabeh and Shandiz Towns, Iran

    Directory of Open Access Journals (Sweden)

    Emadodin Darchini-Maragheh

    2017-07-01

    Full Text Available Introduction: Adolescence is a critical period in life, which is associated with tumultuous transitions and “storm and stress. The present study aimed to evaluate the correlation between depression, anxiety, and stress with the high-risk behaviors among the adolescents in Torghabeh and Shandiz towns, Iran. Materials and Methods: This cross-sectional study was conducted on 90 adolescents from the high schools. Participants were selected via two-stage sampling. Data were collected using the validated Depression, Anxiety, and Stress Scale (DASS-21 and history of high-risk behaviors in the students. Data analysis was performed in SPSS version 16. Results:Variable degrees of depression, anxiety, and stress were reported in 43.3%, 43.3%, and 38.9% of the students, respectively. Although the difference was not statistically significant, female students were more affected by the mentioned disorders compared to the male students. Among the high-risk behaviors, smoking cigarettes was significantly correlated with the depression, anxiety, and stress subscales. In addition, a significant association was observed between opium consumption and stress. However, no significant correlation was observed between smoking hookah and the DASS-21 subscales. Regular alcohol consumption was found to be significantly correlated with the higher rate of depression in the studied adolescents. Also, premarital sexual behaviors had a significant association with the stress and depression subscales. Conclusion: Lack of attention to depression, anxiety, and stress and their risk factors in adolescents may lead to variable degrees of life dissatisfaction in the community. Therefore, it is recommended that on-school mental screening programs be performed for high-school students in order prevent these complications.

  14. Stress-induced hyperthermia in translational stress research

    NARCIS (Netherlands)

    Vinkers, C.H.; Penning, R.; Ebbens, M.M.; Helhammer, J.; Verster, J.C.; Kalkman, C.J.; Olivier, B.

    2010-01-01

    The stress-induced hyperthermia (SIH) response is the transient change in body temperature in response to acute stress. This body temperature response is part of the autonomic stress response which also results in tachycardia and an increased blood pressure. So far, a SIH response has been found in

  15. Teacher Wellness: Too Stressed for Stress Management?

    Science.gov (United States)

    Kipps-Vaughan, Debi; Ponsart, Tyler; Gilligan, Tammy

    2012-01-01

    Healthier, happier teachers promote healthier, happier, and more effective learning environments. Yet, many teachers experience considerable stress. Studies have found that between one fifth and one fourth of teachers frequently experience a great deal of stress (Kyriacou, 1998). Stress in teaching appears to be universal across nations and…

  16. Characterization of residual stresses generated during inhomogeneous plastic deformation

    DEFF Research Database (Denmark)

    Lorentzen, T.; Faurholdt, T.; Clausen, B.

    1998-01-01

    Residual stresses generated by macroscopic inhomogeneous plastic deformation are predicted by an explicit finite element (FE) technique. The numerical predictions are evaluated by characterizing the residual elastic strains by neutron diffraction using two different (hkl) reflections. Intergranular...... compare well and verify the capability of the numerical technique as well as the possibilities of experimental validation using neutron diffraction. The presented experimental and numerical approach will subsequently be utilized for the evaluation of more complicated plastic deformation processes...

  17. [Occupational stress, coping styles and eating habits among Polish employees].

    Science.gov (United States)

    Potocka, Adrianna; Mościcka, Agnieszka

    2011-01-01

    The aim of the study was to analyze potential relations between occupational stress, coping styles and ing habits. Questionnaires administered to 160 public administration employees allowed for assessing eating habits, occupational stress and coping styles. The eating habits correlated with work stress (ro-Spearman's = 0.17-0.29). More unhealthy eating patterns were observed in employees characterized by a higher level of stress. Such stressors as overload, lack of control over work and inappropriate work organization were especially related to poorer eating habits. Among the analyzed coping styles, focusing on emotions (ro-S = 0.19) and searching for emotional support most significantly correlated with poorer eating behaviors (ro-S = 0.16). There were statistically significant differences in eating habits, depending on the level of job stress (U = 1583.50, p stress had a stronger tendency to habitual and emotional eating more than those with a medium level of job stress. The relationship between subjective assessment of job stress, coping and eating habits has been confirmed. Taking into account the role of stress and coping, as the potential determinants of eating patterns in humans, more attention should be paid to education and promotion of knowledge about the relationship between stress and human eating behaviors to prevent obesity and eating disorders.

  18. Thermal stress effects in intermetallic matrix composites

    Science.gov (United States)

    Wright, P. K.; Sensmeier, M. D.; Kupperman, D. S.; Wadley, H. N. G.

    1993-01-01

    Intermetallic matrix composites develop residual stresses from the large thermal expansion mismatch (delta-alpha) between the fibers and matrix. This work was undertaken to: establish improved techniques to measure these thermal stresses in IMC's; determine residual stresses in a variety of IMC systems by experiments and modeling; and, determine the effect of residual stresses on selected mechanical properties of an IMC. X ray diffraction (XRD), neutron diffraction (ND), synchrotron XRD (SXRD), and ultrasonics (US) techniques for measuring thermal stresses in IMC were examined and ND was selected as the most promising technique. ND was demonstrated on a variety of IMC systems encompassing Ti- and Ni-base matrices, SiC, W, and Al2O3 fibers, and different fiber fractions (Vf). Experimental results on these systems agreed with predictions of a concentric cylinder model. In SiC/Ti-base systems, little yielding was found and stresses were controlled primarily by delta-alpha and Vf. In Ni-base matrix systems, yield strength of the matrix and Vf controlled stress levels. The longitudinal residual stresses in SCS-6/Ti-24Al-llNb composite were modified by thermomechanical processing. Increasing residual stress decreased ultimate tensile strength in agreement with model predictions. Fiber pushout strength showed an unexpected inverse correlation with residual stress. In-plane shear yield strength showed no dependence on residual stress. Higher levels of residual tension led to higher fatigue crack growth rates, as suggested by matrix mean stress effects.

  19. Interindividual differences in stress sensitivity: basal and stress-induced cortisol levels differentially predict neural vigilance processing under stress.

    Science.gov (United States)

    Henckens, Marloes J A G; Klumpers, Floris; Everaerd, Daphne; Kooijman, Sabine C; van Wingen, Guido A; Fernández, Guillén

    2016-04-01

    Stress exposure is known to precipitate psychological disorders. However, large differences exist in how individuals respond to stressful situations. A major marker for stress sensitivity is hypothalamus-pituitary-adrenal (HPA)-axis function. Here, we studied how interindividual variance in both basal cortisol levels and stress-induced cortisol responses predicts differences in neural vigilance processing during stress exposure. Implementing a randomized, counterbalanced, crossover design, 120 healthy male participants were exposed to a stress-induction and control procedure, followed by an emotional perception task (viewing fearful and happy faces) during fMRI scanning. Stress sensitivity was assessed using physiological (salivary cortisol levels) and psychological measures (trait questionnaires). High stress-induced cortisol responses were associated with increased stress sensitivity as assessed by psychological questionnaires, a stronger stress-induced increase in medial temporal activity and greater differential amygdala responses to fearful as opposed to happy faces under control conditions. In contrast, high basal cortisol levels were related to relative stress resilience as reflected by higher extraversion scores, a lower stress-induced increase in amygdala activity and enhanced differential processing of fearful compared with happy faces under stress. These findings seem to reflect a critical role for HPA-axis signaling in stress coping; higher basal levels indicate stress resilience, whereas higher cortisol responsivity to stress might facilitate recovery in those individuals prone to react sensitively to stress. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  20. The state of stress in British rocks

    International Nuclear Information System (INIS)

    Klein, R.J.; Brown, E.T.

    1983-03-01

    When designing underground works, it is necessary to take account of not only the vertical stresses arising predictably from the weight of the rock overhead, but also horizontal stresses which may vary from one direction to another as a result of past tectonic action. This report discussed the techniques that have been used to measure such stresses. Few determinations have been made in Great Britain, so it has been necessary to augment what little is known by reference to fault systems, relying on correlations between the measured magnitude and direction of maximum horizontal stress with local tectonic history. This has enabled general conclusions to be reached for Great Britain. (author)

  1. Residual stresses

    International Nuclear Information System (INIS)

    Sahotra, I.M.

    2006-01-01

    The principal effect of unloading a material strained into the plastic range is to create a permanent set (plastic deformation), which if restricted somehow, gives rise to a system of self-balancing within the same member or reaction balanced by other members of the structure., known as residual stresses. These stresses stay there as locked-in stresses, in the body or a part of it in the absence of any external loading. Residual stresses are induced during hot-rolling and welding differential cooling, cold-forming and extruding: cold straightening and spot heating, fabrication and forced fitting of components constraining the structure to a particular geometry. The areas which cool more quickly develop residual compressive stresses, while the slower cooling areas develop residual tensile stresses, and a self-balancing or reaction balanced system of residual stresses is formed. The phenomenon of residual stresses is the most challenging in its application in surface modification techniques determining endurance mechanism against fracture and fatigue failures. This paper discusses the mechanism of residual stresses, that how the residual stresses are fanned and what their behavior is under the action of external forces. Such as in the case of a circular bar under limit torque, rectangular beam under limt moment, reclaiming of shafts welds and peening etc. (author)

  2. Measurement of residual stress by using focused ion beam and digital image correlation method in thin-sized wires used for steel cords

    International Nuclear Information System (INIS)

    Yang, Y S; Park, C G; Bae, J G

    2008-01-01

    Residual stress in the axial direction of the steel wires has been measured by using a method based on the combination of the focused ion beam (FIB) milling and digital image correlation software. That is, the residual stress was calculated from the measured displacement field before and after the introduction of a slot along the steel wires. The displacement was obtained by the digital correlation analysis of high-resolution scanning electron micrographs, while the slot was introduced by FIB milling with low energy beam. The fitting of the experimental results to an analytical model with the independent Young's modulus determined allows us to find the residual stress. The complete experimental procedures are described and its feasibilities are also evaluated for the thin-sized steel wires

  3. Individual trajectories in stress covary with immunity during recovery from cancer diagnosis and treatments.

    Science.gov (United States)

    Thornton, Lisa M; Andersen, Barbara L; Crespin, Timothy R; Carson, William E

    2007-02-01

    Research connects stressful events with altered immune regulation, but the role of subjective stress is uncertain. Using a longitudinal design, we provide a statistically powerful test of the relationship between subjective stress (perceived stress, emotional distress) and immunity (T cell blastogenesis, natural killer cell cytotoxicity, [NKCC]) as individuals adjust to a severe stressor, a cancer diagnosis and its treatments. Women with regional breast cancer (N=113) were assessed at diagnosis/surgery and reassessed 4, 8, 12, and 18 months later. Latent growth curve analysis tested two hypotheses: (1) initial levels of subjective stress will correlate inversely with initial levels of immunity, and (2) rate of change in subjective stress will correlate inversely with rate of change in immunity. As predicted by Hypothesis 1, participants with high initial subjective stress showed poor initial blastogenesis. As predicted by Hypothesis 2, participants exhibiting an early, rapid decline in subjective stress also showed rapid improvement in NKCC. Follow-up analyses revealed perceived stress to be strongly related to immune function, while emotional distress was not. This is the first study to investigate trajectories in stress and immunity during recovery from a major stressor. Results imply that NK and T cells are sensitive to different aspects of the stress response. While T cell blastogenesis correlated with initial (peak) subjective stress, NKCC correlated with change (improvement) in subjective stress. These data highlight the importance of subjective stress, particularly stress appraisals, in the immune response to a major stressor.

  4. Biological effects of laser-induced stress waves

    International Nuclear Information System (INIS)

    Doukas, A.; Lee, S.; McAuliffe, D.

    1995-01-01

    Laser-induced stress waves can be generated by one of the following mechanisms: Optical breakdown, ablation or rapid heating of an absorbing medium. These three modes of laser interaction with matter allow the investigation of cellular and tissue responses to stress waves with different characteristics and under different conditions. The most widely studied phenomena are those of the collateral damage seen in photodisruption in the eye and in 193 run ablation of cornea and skin. On the other hand, the therapeutic application of laser-induced stress waves has been limited to the disruption of noncellular material such as renal stones, atheromatous plaque and vitreous strands. The effects of stress waves to cells and tissues can be quite disparate. Stress waves can fracture tissue, damage cells, and increase the permeability of the plasma membrane. The viability of cell cultures exposed to stress waves increases with the peak stress and the number of pulses applied. The rise time of the stress wave also influences the degree of cell injury. In fact, cell viability, as measured by thymidine incorporation, correlates better with the stress gradient than peak stress. Recent studies have also established that stress waves induce a transient increase of the permeability of the plasma membrane in vitro. In addition, if the stress gradient is below the damage threshhold, the cells remain viable. Thus, stress waves can be useful as a means of drug delivery, increasing the intracellular drug concentration and allowing the use of drugs which are impermeable to the cell membrane. The present studies show that it is important to create controllable stress waves. The wavelength tunability and the micropulse structure of the free electron laser is ideal for generating stress waves with independently adjustable parameters, such as rise time, duration and peak stress

  5. Job Stress and Presenteeism among Chinese Healthcare Workers: The Mediating Effects of Affective Commitment.

    Science.gov (United States)

    Yang, Tianan; Guo, Yina; Ma, Mingxu; Li, Yaxin; Tian, Huilin; Deng, Jianwei

    2017-08-29

    Presenteeism affects the performance of healthcare workers. This study examined associations between job stress, affective commitment, and presenteeism among healthcare workers. To investigate the relationship between job stress, affective commitment, and presenteeism, structural equation modeling was used to analyze a sample of 1392 healthcare workers from 11 Class A tertiary hospitals in eastern, central, and western China. The mediating effect of affective commitment on the association between job stress and presenteeism was examined with the Sobel test. Job stress was high and the level of presenteeism was moderate among healthcare workers. Challenge stress and hindrance stress were strongly correlated (β = 0.62; p < 0.05). Affective commitment was significantly and directly inversely correlated with presenteeism (β = -0.27; p < 0.001). Challenge stress was significantly positively correlated with affective commitment (β = 0.15; p < 0.001) but not with presenteeism. Hindrance stress was significantly inversely correlated with affective commitment (β = -0.40; p < 0.001) but was significantly positively correlated with presenteeism (β = 0.26; p < 0.001). This study provides important empirical data on presenteeism among healthcare workers. Presenteeism can be addressed by increasing affective commitment and challenge stress and by limiting hindrance stress among healthcare workers in China.

  6. Job Stress and Presenteeism among Chinese Healthcare Workers: The Mediating Effects of Affective Commitment

    Directory of Open Access Journals (Sweden)

    Tianan Yang

    2017-08-01

    Full Text Available Background: Presenteeism affects the performance of healthcare workers. This study examined associations between job stress, affective commitment, and presenteeism among healthcare workers. Methods: To investigate the relationship between job stress, affective commitment, and presenteeism, structural equation modeling was used to analyze a sample of 1392 healthcare workers from 11 Class A tertiary hospitals in eastern, central, and western China. The mediating effect of affective commitment on the association between job stress and presenteeism was examined with the Sobel test. Results: Job stress was high and the level of presenteeism was moderate among healthcare workers. Challenge stress and hindrance stress were strongly correlated (β = 0.62; p < 0.05. Affective commitment was significantly and directly inversely correlated with presenteeism (β = −0.27; p < 0.001. Challenge stress was significantly positively correlated with affective commitment (β = 0.15; p < 0.001 but not with presenteeism. Hindrance stress was significantly inversely correlated with affective commitment (β = −0.40; p < 0.001 but was significantly positively correlated with presenteeism (β = 0.26; p < 0.001. Conclusions: This study provides important empirical data on presenteeism among healthcare workers. Presenteeism can be addressed by increasing affective commitment and challenge stress and by limiting hindrance stress among healthcare workers in China.

  7. Managing Leadership Stress

    CERN Document Server

    Bal, Vidula; McDowell-Larsen, Sharon

    2011-01-01

    Everyone experiences stress, and leaders face the additional stress brought about by the unique demands of leadership: having to make decisions with limited information, to manage conflict, to do more with less . . . and faster! The consequences of stress can include health problems and deteriorating relationships. Knowing what signs of stress to look for and having a strategy for increasing your resources will help you manage leadership stress and be more effective over a long career.Table of ContentsThe Stress of Leadership 7Why Is Leadership Stressful? 8Stress Assessment 13When Stress Is Wh

  8. Digital-image-correlation-based experimental stress analysis of reinforced concrete beams strengthened using carbon composites

    Science.gov (United States)

    Helm, Jeffrey; Kurtz, Stephen

    2005-01-01

    The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.

  9. The Relationship Between Surface Curvature and Abdominal Aortic Aneurysm Wall Stress.

    Science.gov (United States)

    de Galarreta, Sergio Ruiz; Cazón, Aitor; Antón, Raúl; Finol, Ender A

    2017-08-01

    The maximum diameter (MD) criterion is the most important factor when predicting risk of rupture of abdominal aortic aneurysms (AAAs). An elevated wall stress has also been linked to a high risk of aneurysm rupture, yet is an uncommon clinical practice to compute AAA wall stress. The purpose of this study is to assess whether other characteristics of the AAA geometry are statistically correlated with wall stress. Using in-house segmentation and meshing algorithms, 30 patient-specific AAA models were generated for finite element analysis (FEA). These models were subsequently used to estimate wall stress and maximum diameter and to evaluate the spatial distributions of wall thickness, cross-sectional diameter, mean curvature, and Gaussian curvature. Data analysis consisted of statistical correlations of the aforementioned geometry metrics with wall stress for the 30 AAA inner and outer wall surfaces. In addition, a linear regression analysis was performed with all the AAA wall surfaces to quantify the relationship of the geometric indices with wall stress. These analyses indicated that while all the geometry metrics have statistically significant correlations with wall stress, the local mean curvature (LMC) exhibits the highest average Pearson's correlation coefficient for both inner and outer wall surfaces. The linear regression analysis revealed coefficients of determination for the outer and inner wall surfaces of 0.712 and 0.516, respectively, with LMC having the largest effect on the linear regression equation with wall stress. This work underscores the importance of evaluating AAA mean wall curvature as a potential surrogate for wall stress.

  10. Affluence, Feelings of Stress, and Well-Being

    Science.gov (United States)

    Ng, Weiting; Diener, Ed; Aurora, Raksha; Harter, James

    2009-01-01

    Data from the Gallup World Poll highlighted the differential relations between perceived stress, well-being, and wealth at the individual- versus nation-level. At the nation level, stress was a distinct concept from negative affect (NA). It correlated positively with well-being (positive affect, life satisfaction, and domain satisfaction) and…

  11. Residual stress in ceramics and ceramic composites

    International Nuclear Information System (INIS)

    Oden, M.

    1992-01-01

    Residual stresses in Si 3 N 4 and SiC have been measured with X-ray diffraction after grinding and thermal shock. The produced surface stresses are compressive after both treatments. The stresses show a strong dependence on the quenching temperature up to a certain temperature when cracks relax the stresses. The influence of the amount of reinforcing phase on the residual stress state in a Al 2 O 3 /SiC whisker composite was investigated and correlated to a modified Eshelby model. The agreement is excellent. The composite was quenched in liquid He (4K) and the stress state measured after show no relaxation of stresses, indicating elastic behaviour. An in situ strain measurement as a function of temperature conducted on a Al 2 O 3 /SiC whisker composite and a SiC/TiB 2 particle composite show very good agreement with the Eshelby model for the Al 2 O 3 /SiC system but not agreement for the SiC/TiB 2 system. The reason is believed to be stress relaxation during sample preparation. (au) (53 refs., 24 figs., 14 tabs.)

  12. Stress shadows - a controversial topic

    Science.gov (United States)

    Lasocki, Stanislaw; Karakostas, Vassilis G.; Papadimitriou, Eletheria E.; Orlecka-Sikora, Beata

    2010-05-01

    The spatial correlation between the positive Coulomb stress changes and the subsequent seismic activity has been firmly confirmed in many recent studies. If, however, the static stress transfer is a consistent expression of interaction between earthquakes one should also observe a decrease of the activity in the zones of negative stress changes. Instead, the existence of stress shadows is poorly evidenced and may be questioned. We tested the influence of the static stress changes associated with the coseismic slip of the 1995 Mw6.5 Kozani-Grevena (Greece) earthquake on locations of its aftershocks. The study was based on a detailed slip model for the main shock and accurate locations and reliable fault plane solutions of an adequate number of the aftershocks. We developed a statistical testing method, which tested whether the proportions of aftershocks located inside areas determined by a selected criterion on the static stress change could be attained if there were no effect of the stress change due to the main shock on aftershock locations. The areas of stress change were determined at the focus of every aftershock. The distribution of test statistic was constructed with the use of a two-dimensional nonparametric, kernel density estimator of the reference epicenter distribution. The tests highly confidently indicated a rise in probability to locate aftershocks inside areas of positive static stress change, which supported the hypothesis on the triggering effect in these areas. Furthermore, it was evidenced that a larger stress increase caused a stronger triggering effect. The analysis, however, did not evidence the existence of stress shadows inside areas of negative stress change. Contrary to expectations, the tests indicated a significant increase of the probability of event location in the areas of a stress decrease of more than or equal to 5.0 and 10.0 bar. It turned out that for areas of larger absolute stress change this probability increased regardless of

  13. Oxidative stress and psychological functioning among medical students

    Directory of Open Access Journals (Sweden)

    Rani Srivastava

    2014-01-01

    Full Text Available Background: Oxidative stress has gained attention recently in behavioral medicine and has been reported to be associated with various psychological disturbances and their prognoses. Objectives: Study aims to evaluate the oxidative stress (malonylaldehyde (MDA levels and its relation with psychological factors (dimensions of personality, levels of anxiety, stress, and depression among medical/paramedical students of 1 st and 3 rd year. Materials and Methods: A total of 150 students; 75 from 1 st year (2010-2011 and75 from 3 rd year (2009-2010; of medical and paramedical background were assessed on level of MDA (oxidative stress and personality variables, that is, level of anxiety, stress, and depression. These psychological variables were correlated with the level of their oxidative stress. Results: Findings revealed that both groups are influenced by oxidative stress and their psychological variables are also compatible in order to confirm their vulnerabilities to stress. Conclusions: Stress in 3 rd year students was significantly higher and it was noted that it adversely affects the psychological parameters. Hence, special attention on mental health aspect in these students may be given.

  14. Occupational Stress

    OpenAIRE

    Löblová, Klára

    2011-01-01

    The thesis deals with load, stress and related questions of the working life. Work-related stress brings numerous difficulties not only to affected individuals, but as a result also to organizations. The thesis follows symptoms, impacts, somatic and mental aspects of stress, its types and also types of stressors, which cause this problem. It is concentrated on workload as a specific area of work-related stress, individual resistance to the load, factors of workload and work-related stress and...

  15. Do Egyptian university students eat more or eat less when perceiving stress?

    DEFF Research Database (Denmark)

    Berg-Beckhoff, Gabriele; El Ansari, Walid

    2015-01-01

    in Egypt. We assessed students’ levels of stress and correlated it with their consumption of a range of food groups. Methods: The cross sectional study was conducted among undergraduates in Egypt (N=3.271: response rate: 90%). The questionnaire contained a short food frequency questionnaire (FFQ......) and the four item short form Cohen’s perceived stress scale. We assessed two composite food intake pattern scores (sweets, cakes and snacks score: and fruits and vegetables score) using FFQ. Spearman correlation coefficient examined the correlations between perceived stress on the one hand, and all food groups......Background: Most studies of stress and food choice found that individuals experiencing periods of stress over-ate food items they would customarily avoid, and that they ate these foods to feel better. This study examined perceived stress and food intake behavior of undergraduate university students...

  16. Residual stress determination in PECVD TiN coatings by X-ray diffraction: a parametric study

    DEFF Research Database (Denmark)

    Thomsen, N.B.; Horsewell, Andy; Mogensen, K.S.

    1998-01-01

    The main objective of this research is to study the residual macroscopic stress in titanium-nitride, TiN, coatings deposited onto a tool steer substrate. The measurements were performed with a theta-theta decoupled X-ray diffractometer. The coatings were manufactured using an industrial pulsed...

  17. The influence of acute stress on attention mechanisms and its electrophysiological correlates

    Directory of Open Access Journals (Sweden)

    Jessica eSänger

    2014-10-01

    Full Text Available For the selection of relevant information out of a continuous stream of information, which is a common definition of attention, two core mechanisms are assumed: a competition-based comparison of the neuronal activity in sensory areas and the top-down modulation of this competition by frontal executive control functions. Those control functions are thought to bias the processing of information towards the intended goals. Acute stress is thought to impair these frontal functions through the release of cortisol.In the present study, subjects had to detect a luminance change of a stimulus and ignore more salient but task irrelevant orientation changes. Before the execution of this task, subjects underwent a socially evaluated cold pressor test (SECPT or a non-stressful control situation. The SECPT revealed reliable stress response with a significant increase of cortisol and alpha-amylase. Stressed subjects showed higher error rates than controls, particularly in conditions which require top-down control processing to bias the less salient target feature against the more salient and spatially separated distracter.By means of the EEG, subjects who got stressed showed a reduced allocation to the relevant luminance change apparent in a modulation of the N1pc. The following N2pc, which reflects a re-allocation of attentional resources, supports the error pattern. There was only an N2pc in conditions, which required to bias the less salient luminance change. Moreover, this N2pc was decreased as a consequence of the induced stress. These results allow the conclusion that acute stress impairs the intention-based attentional allocation and enhances the stimulus-driven selection, leading to a strong distractibility during attentional information selection.

  18. Analyzing the Correlation between Dealing with Stress and Self-Esteem of the Participants Who Are 25 Years Old and Younger

    Directory of Open Access Journals (Sweden)

    Barbaros Serdar ERDOĞAN

    2015-03-01

    Full Text Available The aim of the study is to investigate the correlation between the attitudes of young people who do sports and their self-esteem. The research group included 83 men and 117 women ( age=21,49 + 1,659, as a total 200, who make exercises at least 1 year in special gym center in Antalya and Konya . Self-esteem scale developed by Arıcak (1999 and Dealing with Stress Scales developed by Özbay (1993 were used to reach the aim of the study. Meaningfulness was acquired as P<0,05 by using Kolmogorov-Smirnov test, t testand Pearson Correlation while commenting on the data. SPSS (Statistical package for social sciencesprogramme was used to evaluate the data. At the end of the research meaningful and direct correlation was acquired .01 (P<0,01 between sub dimensions active planning of dealing with stress and value of ego (r=497, self- confident (r=577, depressive emotion (r=531, self-sufficiency (r=572, succsess and productivity (r=476 As a general result different attitudes to cope with the stress were seen in the youth participants because of their gender’s characteristics and it was thought that the correlation between those attitudes and their self -esteem was at the medium and higher-up level.

  19. Occupational stress among Swedish audiologists in clinical practice: Reasons for being stressed.

    Science.gov (United States)

    Brännström, K Jonas; Holm, Lucas; Larsson, Josefina; Lood, Sofie; Notsten, Margareta; Turunen Taheri, Satu

    2016-08-01

    The present study reports on the application of a Swedish translation of the audiologist occupational stress questionnaire (AOSQ) on audiologists working in Sweden. The relations between AOSQ scores and perceived effort, perceived rewards, coping strategies at work, demographic variables such as salary, education length, practise length, and practice type were tested. A cross-sectional e-mail survey using the AOSQ, effort-reward imbalance questionnaire, and demographic questions. Four-hundred and four Swedish licensed audiologists working with clients. The Swedish AOSQ translation demonstrated high inter-item correlations and high internal consistency. Several stress factors were identified: time spent at work, accountability, leadership at the workplace, paperwork and practice demands, equipment and clinical protocols, own health concerns, and job control. The outcome on the complete AOSQ questionnaire was related to perceived effort, perceived rewards, coping strategies at work, and age. The Swedish AOSQ translation seems to provide a valid measure of occupational stress among audiologists.

  20. Adult Autism Subthreshold Spectrum (AdAS Spectrum) in parents of pediatric patients with epilepsy: Correlations with post-traumatic stress symptoms.

    Science.gov (United States)

    Dell'Osso, L; Corsi, M; Gesi, C; Bertelloni, C A; Massimetti, G; Peroni, D; Bonuccelli, A; Orsini, A; Carmassi, C

    2018-05-01

    Increasing literature has shown the usefulness of a dimensional approach to mental disorders, particularly when exploring subjects exposed to traumatic experiences such as a severe illness in one's child. Recent evidence suggests an increased vulnerability in subjects with autism spectrum symptoms to develop post-traumatic stress symptoms. The aim of the present study was to evaluate the presence of adult autism subthreshold spectrum in a sample of parents of children with epilepsy and its impact on post-traumatic stress spectrum symptoms in the same study sample. Results revealed noteworthy correlations between post-traumatic stress symptoms and adult autism subthreshold spectrum (AdAS Spectrum) only in the subgroup of the fathers. In particular, were evidenced correlations between AdAS Spectrum domain of rumination and narrow interests and some TALS-SR nuclear domains: reaction to traumatic events, reexperiencing and arousal. These findings corroborate the hypothesis that subthreshold autistic features may influence the possible psychopathological reaction to trauma. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Constraints on Stress Components at the Internal Singular Point of an Elastic Compound Structure

    Science.gov (United States)

    Pestrenin, V. M.; Pestrenina, I. V.

    2017-03-01

    The classical analytical and numerical methods for investigating the stress-strain state (SSS) in the vicinity of a singular point consider the point as a mathematical one (having no linear dimensions). The reliability of the solution obtained by such methods is valid only outside a small vicinity of the singular point, because the macroscopic equations become incorrect and microscopic ones have to be used to describe the SSS in this vicinity. Also, it is impossible to set constraint or to formulate solutions in stress-strain terms for a mathematical point. These problems do not arise if the singular point is identified with the representative volume of material of the structure studied. In authors' opinion, this approach is consistent with the postulates of continuum mechanics. In this case, the formulation of constraints at a singular point and their investigation becomes an independent problem of mechanics for bodies with singularities. This method was used to explore constraints at an internal singular point (representative volume) of a compound wedge and a compound rib. It is shown that, in addition to the constraints given in the classical approach, there are also constraints depending on the macroscopic parameters of constituent materials. These constraints turn the problems of deformable bodies with an internal singular point into nonclassical ones. Combinations of material parameters determine the number of additional constraints and the critical stress state at the singular point. Results of this research can be used in the mechanics of composite materials and fracture mechanics and in studying stress concentrations in composite structural elements.

  2. Stress and Health

    DEFF Research Database (Denmark)

    Rod, Naja Hulvej

    2014-01-01

    Background Stress is an important public health issue. One in ten Danish adults experience high levels of stress in their daily lives and stress is one of the main occupational health problems in Europe. The link between stress and health is still debated in the scientific literature...... and the pathways underlying these potential health effects are far from elucidated. The dissertation contributions to the literature on stress and health by empirically testing the relationship between stress and major chronic disorders and by providing new evidence on the underlying physiological, psychological...... and behavioral mechanisms. Stress is a complex concept and in order to better understand the relation between stress and health, the dissertation works with a clear distinction between the health consequences of different types of stress including external stressors, perceived stress, and measures of the stress...

  3. The Effect of Stochastically Varying Creep Parameters on Residual Stresses in Ceramic Matrix Composites

    Science.gov (United States)

    Pineda, Evan J.; Mital, Subodh K.; Bednarcyk, Brett A.; Arnold, Steven M.

    2015-01-01

    Constituent properties, along with volume fraction, have a first order effect on the microscale fields within a composite material and influence the macroscopic response. Therefore, there is a need to assess the significance of stochastic variation in the constituent properties of composites at the higher scales. The effect of variability in the parameters controlling the time-dependent behavior, in a unidirectional SCS-6 SiC fiber-reinforced RBSN matrix composite lamina, on the residual stresses induced during processing is investigated numerically. The generalized method of cells micromechanics theory is utilized to model the ceramic matrix composite lamina using a repeating unit cell. The primary creep phases of the constituents are approximated using a Norton-Bailey, steady state, power law creep model. The effect of residual stresses on the proportional limit stress and strain to failure of the composite is demonstrated. Monte Carlo simulations were conducted using a normal distribution for the power law parameters and the resulting residual stress distributions were predicted.

  4. Standard test method for verifying the alignment of X-Ray diffraction instrumentation for residual stress measurement

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the preparation and use of a flat stress-free test specimen for the purpose of checking the systematic error caused by instrument misalignment or sample positioning in X-ray diffraction residual stress measurement, or both. 1.2 This test method is applicable to apparatus intended for X-ray diffraction macroscopic residual stress measurement in polycrystalline samples employing measurement of a diffraction peak position in the high-back reflection region, and in which the θ, 2θ, and ψ rotation axes can be made to coincide (see Fig. 1). 1.3 This test method describes the use of iron powder which has been investigated in round-robin studies for the purpose of verifying the alignment of instrumentation intended for stress measurement in ferritic or martensitic steels. To verify instrument alignment prior to stress measurement in other metallic alloys and ceramics, powder having the same or lower diffraction angle as the material to be measured should be prepared in similar fashion...

  5. College Student Stress and Satisfaction with Life

    Science.gov (United States)

    Weinstein, Lawrence; Laverghetta, Antonio

    2009-01-01

    The following study was performed to determine if general life satisfaction is negatively correlated with college student stress. We administered the satisfaction with life scale (Diener et al., 1985), college student stress scale (Feldt, 2008) and a brief demographics survey to a sample of college students at a regional southwestern university in…

  6. Stressful life events, vulnerable to stress and depression among ...

    African Journals Online (AJOL)

    The present study was carried out to observe the difference between male and female Eritrean students on the basis of stressful life events, vulnerable to stress and depression. Stressful life Events Questionnaire, Vulnerable to Stress Instrument and Beck Depression Scale were administered to gather information. The data ...

  7. Correlation of serum GFAP, S100B and NSE contents with posttraumatic oxidative stress response and insulin resistance in patients with traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Bing-Feng Tian

    2018-07-01

    Full Text Available Objective: To study the correlation of serum GFAP, S100B and NSE contents with posttraumatic oxidative stress response and insulin resistance in patients with traumatic brain injury. Methods: A total of 110 patients with traumatic brain injury who were treated in our hospital between January 2015 and December 2016 were collected as the observation group, and 60 healthy subjects who received physical examination in our hospital during the same period were collected as normal control group. Serum GFAP, S100B and NSE levels as well as oxidative stress index and insulin resistance index levels of two groups of subjects were detected, and Pearson test was used to further evaluate the correlation of serum GFAP, S100B and NSE contents with oxidative stress response and insulin resistance in patients with traumatic brain injury. Results: Serum GFAP, S100B and NSE contents of observation group were significantly higher than those of normal control group; serum oxidative stress indexes MDA, MPO and LPO contents were higher than those of normal control group while SOD and TAC contents were lower than those of normal control group; serum insulin resistance indexes GLU, INS and HOMA-IR levels were higher than those of control group. Pearson test showed that serum GFAP, S100B and NSE contents in patients with traumatic brain injury were directly correlated with post-traumatic oxidative stress and insulin resistance. Conclusion: The serum GFAP, S100B and NSE contents increase in patients with traumatic brain injury, and the increase is directly correlated with the oxidative stress and insulin resistance.

  8. Cyclic Strain Resistance, Stress Response, Fatigue Life, and Fracture Behavior of High Strength Low Alloy Steel 300 M

    Science.gov (United States)

    Manigandan, K.; Srivatsan, T. S.; Tammana, Deepthi; Poorgangi, Behrang; Vasudevan, Vijay K.

    2014-05-01

    The focus of this technical manuscript is a record of the specific role of microstructure and test specimen orientation on cyclic stress response, cyclic strain resistance, and cyclic stress versus strain response, deformation and fracture behavior of alloy steel 300 M. The cyclic strain amplitude-controlled fatigue properties of this ultra-high strength alloy steel revealed a linear trend for the variation of log elastic strain amplitude with log reversals-to-failure, and log plastic strain amplitude with log reversals-to-failure for both longitudinal and transverse orientations. Test specimens of the longitudinal orientation showed only a marginal improvement over the transverse orientation at equivalent values of plastic strain amplitude. Cyclic stress response revealed a combination of initial hardening for the first few cycles followed by gradual softening for a large portion of fatigue life before culminating in rapid softening prior to catastrophic failure by fracture. Fracture characteristics of test specimens of this alloy steel were different at both the macroscopic and fine microscopic levels over the entire range of cyclic strain amplitudes examined. Both macroscopic and fine microscopic observations revealed fracture to be a combination of both brittle and ductile mechanisms. The underlying mechanisms governing stress response, deformation characteristics, fatigue life, and final fracture behavior are presented and discussed in light of the competing and mutually interactive influences of test specimen orientation, intrinsic microstructural effects, deformation characteristics of the microstructural constituents, cyclic strain amplitude, and response stress.

  9. Coupling effects of chemical stresses and external mechanical stresses on diffusion

    International Nuclear Information System (INIS)

    Xuan Fuzhen; Shao Shanshan; Wang Zhengdong; Tu Shantung

    2009-01-01

    Interaction between diffusion and stress fields has been investigated extensively in the past. However, most of the previous investigations were focused on the effect of chemical stress on diffusion due to the unbalanced mass transport. In this work, the coupling effects of external mechanical stress and chemical stress on diffusion are studied. A self-consistent diffusion equation including the chemical stress and external mechanical stress gradient is developed under the framework of the thermodynamic theory and Fick's law. For a thin plate subjected to unidirectional tensile stress fields, the external stress coupled diffusion equation is solved numerically with the help of the finite difference method for one-side and both-side charging processes. Results show that, for such two types of charging processes, the external stress gradient will accelerate the diffusion process and thus increase the value of concentration while reducing the magnitude of chemical stress when the direction of diffusion is identical to that of the stress gradient. In contrast, when the direction of diffusion is opposite to that of the stress gradient, the external stress gradient will obstruct the process of solute penetration by decreasing the value of concentration and increasing the magnitude of chemical stress. For both-side charging process, compared with that without the coupling effect of external stress, an asymmetric distribution of concentration is produced due to the asymmetric mechanical stress field feedback to diffusion.

  10. Correlation of 0.67um scatter with local stress in Ge impacted with the modified Cambridge liquid jet device

    Science.gov (United States)

    Wilson, Michael; Price, D.; Strohecker, Steve

    1994-09-01

    Germanium witness samples were impacted with the NAWCADWAR modified Cambridge liquid jet device introducing varying levels of damage about the center of each sample. Surface damage statistics were collected, scatter measurements were made at 0.67 micrometers and the samples were failed in tension using a bi-axial flexure test setup. The level and character of the damage was correlated with the reflected scatter measurements as a function of local stress and flaw size distribution. Bi-axial flexure data was analyzed to predict fracture stress and the probability of failure of the germanium samples. The mechanical data were then correlated with the scatter data in order to correlate the BRDF with the material failure. The BRDF measurements were taken in several different orientations in order to study the differences in scatter character for the in-plane and out-of-plane conditions.

  11. Stressing Academia? Stress-as-Offence-to-Self at Danish Universities

    Science.gov (United States)

    Opstrup, Niels; Pihl-Thingvad, Signe

    2016-01-01

    Academic work has traditionally been seen as relatively stress free. However, a growing number of studies have reported increases in occupational stress experienced by university researchers. In order to explain stress among this group, we build on a new perspective in occupational stress research: the so-called stress-as-offence-to-self…

  12. Development of two short measures for recovery and stress in sport.

    Science.gov (United States)

    Nässi, Anu; Ferrauti, Alexander; Meyer, Tim; Pfeiffer, Mark; Kellmann, Michael

    2017-08-01

    The Acute Recovery and Stress Scale (ARSS) and the Short Recovery and Stress Scale were first established in German for the purposes of monitoring athletes' current recovery-stress states in an economical and multidimensional manner. The aim of this paper is to document the development and initial validation of the English versions of these two psychometric monitoring tools. A total of 267 English-speaking athletes from a variety of team and individual sports participated in the study. The English versions demonstrated satisfactory internal consistency for both instruments (Cronbach α of .74-.89). Furthermore, good model fit was found for the eight scales of the ARSS, matching the structure and results of the German counterparts. Correlations among and between the scales reciprocate the theoretical constructs of stress and recovery, supporting the construct validity of the scales. Correlation coefficients within stress and recovery ranged between r s  = .29 and .68. The correlations between stress and recovery varied between r s  = -.29 and -.64. These constructs were further supported by correlations with the scores of the Recovery-Stress Questionnaire for Athletes, thereby showing convergent validity. The findings demonstrate initial validity and reliability of the two measures and reflect the results of the German versions. However, further research is needed before applying these scales in practical settings.

  13. A study on stress analysis of small punch-creep test and its experimental correlations with uniaxial-creep test

    International Nuclear Information System (INIS)

    Lee, Song In; Baek, Seoung Se; Kwon, Il Hyun; Yu, Hyo Sun

    2002-01-01

    A basic research was performed to ensure the usefulness of Small Punch-creep(SP-creep) test for residual life evaluation of heat resistant components effectively. This paper presents analytical results of initial stress and strain distributions in SP specimen caused by constant loading for SP-creep test and its experimental correlations with uniaxial creep(Ten-creep) test on 9CrlMoVNb steel. It was shown that the initial maximum equivalent stress, σ eq · max from FE analysis was correlated with steady-state equivalent creep strain rate, ε qf-ss , rupture time, t r , activation energy, Q and Larson-Miller parameter, LMP during SP-creep deformation. The simple correlation laws, σ SP - σ TEN , P SP -σ TEN and Q SP -Q TEN adopted to established a quantitative correlation between SP-creep and Ten-creep test data. Especially, the activation energy obtained from SP-creep test is linearly related to that from Ten-creep test at 650 deg. C as follows : Q SP-P =1.37 Q TEN , Q SP-σ =1.53 Q TEN

  14. Interfacial shear stress in stratified flow in a horizontal rectangular duct

    International Nuclear Information System (INIS)

    Lorencez, C.; Kawaji, M.; Murao, Y.

    1995-01-01

    Interfacial shear stress has been experimentally examined for both cocurrent and countercurrent stratified wavy flows in a horizontal interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress values at high gas flow rates which could be attributed to the assumptions and procedures involved in each method. The interfacial waves and secondary motions were also found to have significant effects on the accuracy of Reynolds stress and turbulence kinetic energy extrapolation methods

  15. Interfacial shear stress in stratified flow in a horizontal rectangular duct

    Energy Technology Data Exchange (ETDEWEB)

    Lorencez, C.; Kawaji, M. [Univ. of Toronto (Canada); Murao, Y. [Tokushima Univ. (Japan)] [and others

    1995-09-01

    Interfacial shear stress has been experimentally examined for both cocurrent and countercurrent stratified wavy flows in a horizontal interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress values at high gas flow rates which could be attributed to the assumptions and procedures involved in each method. The interfacial waves and secondary motions were also found to have significant effects on the accuracy of Reynolds stress and turbulence kinetic energy extrapolation methods.

  16. Work-related stress: A survey of Indian anesthesiologists.

    Science.gov (United States)

    Bakshi, Sumitra Ganesh; Divatia, Jigeeshu Vasishtha; Kannan, Sadhana; Myatra, Sheila Nainan

    2017-01-01

    Work-related stress is common among medical caregivers and concerns all perioperative care providers. Although anesthesiologists are known to experience stress, there are limited Indian data addressing this issue. This survey was conducted among Indian anesthesiologists to determine their awareness about work stress and views regarding prevention programs. A survey questionnaire was distributed to delegates visiting the exhibits at the national anesthesiology conference in 2011. The questionnaire had ten questions on the work pattern, five on work-related stress, nine on opinion regarding the need and willingness to participate in stress-related programs. There were 1178 responders. Forty-three percent were faculty in medical institutions, 26% were residents and 25% were in free-lance practice. Ninety-one percent of participants rated their stress as moderate-extreme. There was a significant correlation between the amount of stress and working for more than 8 h ( P working on weekends ( P = 0.002), and carrying work back home ( P work stress. Eighty-four percent of participants felt the need for stress management programs and 69% expressed their willingness to participate in the same. The majority of participants rated their stress as moderate-extreme and was higher in anesthesiologists working long hours, over the weekend and those handling high-risk patients. A majority of participants felt the survey made them think about work-related stress and expressed their willingness to participate in stress management programs.

  17. Thinner regions of intracranial aneurysm wall correlate with regions of higher wall shear stress: a 7.0 tesla MRI

    Science.gov (United States)

    Blankena, Roos; Kleinloog, Rachel; Verweij, Bon H.; van Ooij, Pim; ten Haken, Bennie; Luijten, Peter R.; Rinkel, Gabriel J.E.; Zwanenburg, Jaco J.M.

    2016-01-01

    Purpose To develop a method for semi-quantitative wall thickness assessment on in vivo 7.0 tesla (7T) MRI images of intracranial aneurysms for studying the relation between apparent aneurysm wall thickness and wall shear stress. Materials and Methods Wall thickness was analyzed in 11 unruptured aneurysms in 9 patients, who underwent 7T MRI with a TSE based vessel wall sequence (0.8 mm isotropic resolution). A custom analysis program determined the in vivo aneurysm wall intensities, which were normalized to signal of nearby brain tissue and were used as measure for apparent wall thickness (AWT). Spatial wall thickness variation was determined as the interquartile range in AWT (the middle 50% of the AWT range). Wall shear stress was determined using phase contrast MRI (0.5 mm isotropic resolution). We performed visual and statistical comparisons (Pearson’s correlation) to study the relation between wall thickness and wall shear stress. Results 3D colored AWT maps of the aneurysms showed spatial AWT variation, which ranged from 0.07 to 0.53, with a mean variation of 0.22 (a variation of 1.0 roughly means a wall thickness variation of one voxel (0.8mm)). In all aneurysms, AWT was inversely related to WSS (mean correlation coefficient −0.35, P<0.05). Conclusions A method was developed to measure the wall thickness semi-quantitatively, using 7T MRI. An inverse correlation between wall shear stress and AWT was determined. In future studies, this non-invasive method can be used to assess spatial wall thickness variation in relation to pathophysiologic processes such as aneurysm growth and –rupture. PMID:26892986

  18. Deformation correlations, stress field switches and evolution of an orogenic intersection: The Pan-African Kaoko-Damara orogenic junction, Namibia

    Directory of Open Access Journals (Sweden)

    Ben Goscombe

    2017-11-01

    Full Text Available Age calibrated deformation histories established by detailed mapping and dating of key magmatic time markers are correlated across all tectono-metamorphic provinces in the Damara Orogenic System. Correlations across structural belts result in an internally consistent deformation framework with evidence of stress field rotations with similar timing, and switches between different deformation events. Horizontal principle compressive stress rotated clockwise ∼180° in total during Kaoko Belt evolution, and ∼135° during Damara Belt evolution. At most stages, stress field variation is progressive and can be attributed to events within the Damara Orogenic System, caused by changes in relative trajectories of the interacting Rio De La Plata, Congo, and Kalahari Cratons. Kaokoan orogenesis occurred earliest and evolved from collision and obduction at ∼590 Ma, involving E–W directed shortening, progressing through different transpressional states with ∼45° rotation of the stress field to strike-slip shear under NW–SE shortening at ∼550–530 Ma. Damaran orogenesis evolved from collision at ∼555–550 Ma with NW–SE directed shortening in common with the Kaoko Belt, and subsequently evolved through ∼90° rotation of the stress field to NE–SW shortening at ∼512–508 Ma. Both Kaoko and Damara orogenic fronts were operating at the same time, with all three cratons being coaxially convergent during the 550–530 Ma period; Rio De La Plata directed SE against the Congo Craton margin, and both together over-riding the Kalahari Craton margin also towards the SE. Progressive stress field rotation was punctuated by rapid and significant switches at ∼530–525 Ma, ∼508 Ma and ∼505 Ma. These three events included: (1 Culmination of main phase orogenesis in the Damara Belt, coinciding with maximum burial and peak metamorphism at 530–525 Ma. This occurred at the same time as termination of transpression and initiation of

  19. Posttraumatic stress disorder in hospitalized adolescents: psychiatric comorbidity and clinical correlates.

    Science.gov (United States)

    Lipschitz, D S; Winegar, R K; Hartnick, E; Foote, B; Southwick, S M

    1999-04-01

    To describe the diagnostic comorbidity and clinical correlates of posttraumatic stress disorder (PTSD) in adolescent psychiatric inpatients. Seventy-four adolescent inpatients were given a structured diagnostic interview, the revised version of the Diagnostic Interview for Children and Adolescents, and a battery of standard self-report measures to assess general trauma exposure, posttraumatic stress symptoms, suicidal behavior, dissociation, and depression. Ninety-three percent of subjects reported exposure to at least one traumatic event such as being a witness/victim of community violence, witnessing family violence, or being the victim of physical/sexual abuse. Thirty-two percent of subjects met diagnostic criteria for current PTSD, with sexual abuse cited as the most common traumatic stressor in 69% of PTSD cases. Girls were significantly more likely to develop PTSD than boys, although the total number of types of trauma did not differ by gender. Compared with psychiatric controls, male youngsters with PTSD were significantly more likely to have comorbid diagnoses of eating disorders, other anxiety disorders, and somatization disorder. Furthermore, male and female youngsters with PTSD were significantly more likely to have attempted suicide and report greater depressive and dissociative symptoms. In clinical populations of hospitalized adolescents exposed to multiple forms of trauma, PTSD is a common, but highly comorbid disorder. Specific multimodal assessments and treatments targeted to both PTSD and its comorbidity profile are warranted.

  20. Stress and Coping with Stress in Adolescence

    Directory of Open Access Journals (Sweden)

    Petra Dolenc

    2015-12-01

    Full Text Available Because of the many developmental changes in adolescence, young people are exposed to greater likelihood of experiencing stress. On the other hand, this period is critical for developing effective and constructive coping strategies. In the contribution, we summarize part of what is known about stress, stress responses and coping. Throughout, we focus on common stressful events among adolescents and emphasize the importance of dealing successfully with stressors in their daily lives. Finally, we highlight the most frequently used instruments to measure coping behaviour in youth and present an overview of the research findings on differences in coping among adolescents according to age and gender.

  1. The Relationship between Personality, Sense of Efficacy, and Stress in Korean Teachers

    Science.gov (United States)

    Park, Subin; Song, Yul-Mai; Ko, Guy-Nueo; Jhung, Kyungun; Ha, Kyooseob; Lee, Young-Ryeol

    2016-01-01

    Several studies have linked teachers' personality characteristics and sense of efficacy to stress. However, investigating the relationship between these three constructs in this context was limited. This study aims to investigate the relationship between personality, sense of efficacy and perceived stress among Korean teachers. A total of 137 teachers working in elementary, middle, and high schools located in Seoul, South Korea were recruited for the study. The participants were administered Temperament and Character Inventory, Teacher's Sense of Efficacy Scale (TSES), and Perceived Stress Scale. The TSES was negatively correlated with harm avoidance and positively correlated with persistence, self-directedness, cooperativeness, and self-transcendence. Perceived stress was positively correlated with harm avoidance and negatively correlated with persistence and self-directedness. The path analysis showed that harm avoidance directly predicted perceived stress (β=0.37, 95% CI=0.21–0.53, p=0.002), and self-directedness and persistence predicted one's sense of efficacy (β=0.18, 95% CI=0.01–0.39 and β=0.31, 95% CI=0.10–0.47), which predicted perceived stress (β=-0.21, 95% CI=-0.39 to -0.02). The results of the present study indicate that harm avoidance might be associated with stress-proneness, while persistence, self-directedness, and sense of efficacy might act as protective resources against stress in Korean teachers. PMID:27757136

  2. The Relationship between Personality, Sense of Efficacy, and Stress in Korean Teachers.

    Science.gov (United States)

    Park, Subin; Song, Yul-Mai; Ko, Guy-Nueo; Jhung, Kyungun; Ha, Kyooseob; Lee, Young-Ryeol; Kim, Yeni

    2016-09-01

    Several studies have linked teachers' personality characteristics and sense of efficacy to stress. However, investigating the relationship between these three constructs in this context was limited. This study aims to investigate the relationship between personality, sense of efficacy and perceived stress among Korean teachers. A total of 137 teachers working in elementary, middle, and high schools located in Seoul, South Korea were recruited for the study. The participants were administered Temperament and Character Inventory, Teacher's Sense of Efficacy Scale (TSES), and Perceived Stress Scale. The TSES was negatively correlated with harm avoidance and positively correlated with persistence, self-directedness, cooperativeness, and self-transcendence. Perceived stress was positively correlated with harm avoidance and negatively correlated with persistence and self-directedness. The path analysis showed that harm avoidance directly predicted perceived stress (β=0.37, 95% CI=0.21-0.53, p=0.002), and self-directedness and persistence predicted one's sense of efficacy (β=0.18, 95% CI=0.01-0.39 and β=0.31, 95% CI=0.10-0.47), which predicted perceived stress (β=-0.21, 95% CI=-0.39 to -0.02). The results of the present study indicate that harm avoidance might be associated with stress-proneness, while persistence, self-directedness, and sense of efficacy might act as protective resources against stress in Korean teachers.

  3. Pre-cold stress increases acid stress resistance and induces amino ...

    African Journals Online (AJOL)

    Pre-cold stress increases acid stress resistance and induces amino acid homeostasis in Lactococcus lactis NZ9000. ... Purpose: To investigate the effects of pre-cold stress treatments on subsequent acid stress resistance ... from 32 Countries:.

  4. Prevalence and correlates of posttraumatic stress disorder among ...

    African Journals Online (AJOL)

    Context: Posttraumatic stress disorder (PTSD) is the most common consequence of traumatic experiences. The North Central Nigeria to which Plateau State belongs has witnessed many ethno‑religious crises. While previous studies suggested a high prevalence of PTSD among students, to the best of our knowledge, ...

  5. Residual stresses

    International Nuclear Information System (INIS)

    Macherauch, E.

    1978-01-01

    Residual stresses are stresses which exist in a material without the influence of external powers and moments. They come into existence when the volume of a material constantly changes its form as a consequence of mechanical, thermal, and/or chemical processes and is hindered by neighbouring volumes. Bodies with residual stress are in mechanical balance. These residual stresses can be manifested by means of all mechanical interventions disturbing this balance. Acoustical, optical, radiological, and magnetical methods involving material changes caused by residual stress can also serve for determining residual stress. Residual stresses have an ambivalent character. In technical practice, they are feared and liked at the same time. They cause trouble because they can be the cause for unexpected behaviour of construction elements. They are feared since they can cause failure, in the worst case with catastrophical consequences. They are appreciated, on the other hand, because, in many cases, they can contribute to improvements of the material behaviour under certain circumstances. But they are especially liked for their giving convenient and (this is most important) mostly uncontrollable explanations. For only in very few cases we have enough knowledge and possibilities for the objective evaluation of residual stresses. (orig.) [de

  6. Role of stress areas, stress severity, and stressful life events on the onset of depressive disorder: a case-control study.

    Science.gov (United States)

    Lueboonthavatchai, Peeraphon

    2009-09-01

    Although the stress and stressful life events are known as the precipitation of depressive disorder, the areas of stress and types of stressful life events found in depression are varied by different socio-cultural context. Identify the stress areas, stress severity, and types of stressful life events associated with the onset of depressive disorder in Thai depressed patients. Ninety depressed and ninety non-depressed subjects, aged above 18 years old, from the Department of Psychiatry, King Chulalongkorn Memorial Hospital, were recruited into the present study between July 2007 and January 2008. All subjects completed a demographic data form, and a 1-Year Life Stress Event Questionnaire. The association between the number of stressful life events, stress areas, stress severity, types of stressful life events, and the onset of depressive disorder were analyzed by independent t-test and chi-square test. Logistic regression was performed to identify the predictors of depressive disorder. Most of the subjects were young and middle-aged women, living in Bangkok and the central region. The depressed subjects experienced more stressful life events than the non-depressed subjects (5.81 +/- 3.19 vs. 3.24 +/- 2.80 events in one year) (p stress areas (health-related, family-related, financial, occupational, and social stress), and overall stress were associated with the onset of depressive disorder (p stress in all areas were at the higher risk of depressive disorder than those with the mild stress (p stress was the stress area highest associated with the depressive disorder (OR = 5.93, 95% CI = 2.33-16.92, p stressful life events associated with the onset of depressive disorder were the medical hospitalization, medical illness leading to missing work or disturbed daily routine, change in sleeping habits, absence of recreation, arguments with spouse, sexual difficulties with spouse, family financial problems, job loss, and trouble with boss (p stress was the significant

  7. Are Geotehrmal Reservoirs Stressed Out?

    Science.gov (United States)

    Davatzes, N. C.; Laboso, R. C.; Layland-Bachmann, C. E.; Feigl, K. L.; Foxall, W.; Tabrez, A. R.; Mellors, R. J.; Templeton, D. C.; Akerley, J.

    2017-12-01

    correlation between the reservoir geometry and models of the local stress state.

  8. Some phonetic experiments on : Double stress and rhythmic variation in R.P. English

    NARCIS (Netherlands)

    Heuven, van V.J.J.P.

    1974-01-01

    This thesis examines the phonetic nature of so-called double-stressed words in English (also called equal- stressed or even-stressed), and the susceptibility of these words to rhythmic adjustment (stress clash avoidance). An acoustic analysis of stress correlates was made of disyllabic words

  9. Relationship between occupational stress and cardiovascular diseases risk factors in drivers.

    Science.gov (United States)

    Biglari, Hamed; Ebrahimi, Mohammad Hossein; Salehi, Maryam; Poursadeghiyan, Mohsen; Ahmadnezhad, Iman; Abbasi, Milad

    2016-11-18

    Of all work stressors, occupational stress is the leading cause of many disorders among workers. Drivers are classified as a high risk group for work related stress. This study set out to determine the relationship between risk factors of cardiovascular diseases and occupational stress among drivers. Two hundred and twenty two Ilam's intercity drivers were selected for the study. For measuring work stress, the Osipow work stress questionnaire was used. After a 10-h fasting period, systolic and diastolic blood pressure was recorded. Intravenous blood samples were taken to determine cholesterol, triglyceride and blood glucose levels. The independent samples t-test and Pearson's correlation test were used to assess the relationship between variables and occupational stress. Seventy-one percent of the intercity drivers suffered from average to acute stress, and 3.1% of them suffered from acute stress. There was no significant relationship between occupational stress and diastolic blood pressure (p = 0.254) among the drivers. Nevertheless, the Pearson's correlation test demonstrated a strong relationship between work stress and blood glucose (p stress were observed in the Ilam's intercity drivers. Occupational stress may have effect on blood glucose levels but the results did not suggest a considerable relationship between risk factors of cardiovascular diseases and occupational stress among intercity drivers. Int J Occup Med Environ Health 2016;29(6):895-901. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  10. The role of social support on occupational stress among hospital nurses.

    Science.gov (United States)

    Yu, Jiegen; Ren, Xiaohua; Wang, Quanhai; He, Lianping; Wang, Jinquan; Jin, Yuelong; Chen, Yan; Wang, Linghong; Nie, Zhonghua; Guo, Daoxia; Yao, Yingshui

    2014-01-01

    Stress is a nonspecific reaction to everything the body needs. Although occupational stress exists in every occupation, it is seen with more frequency and intensity amongst those occupations related to human health. In this study, we aimed to investigate the relationship between occupational stress and social support (SS) among hospital nurses. A cross-sectional survey was conducted among 1144 hospital nurse in China. They were investigated with a self-administered questionnaire about socio-demographic characteristics, occupational stress and social support. A validated version of the revised Occupational Stress Inventory (OSI-R) was applied to evaluate occupational stress; SS was measured by nine questions. Logistic regression analysis was used to study the association between occupational stress and SS and adjusted for income, gender, marital status, working years, educational level, and profession. Of 1144 nurses, the majority age group was less than 30 years, and the mean age across participants was 31.8 years. Further correlation analysis indicated that score of ORQ and PSQ had a significant negative correlation with score of SS (Poccupational stress in hospitals nurse. We also should pay more attention to occupational stress of married and long working years nurse.

  11. Perceived stress and dietary choices: The moderating role of stress management.

    Science.gov (United States)

    Errisuriz, Vanessa L; Pasch, Keryn E; Perry, Cheryl L

    2016-08-01

    Many college students exhibit unhealthy eating behaviors, consuming large quantities of high-fat foods and few fruits and vegetables. Perceived stress has been linked to daily dietary choices among college students; however, this work has been conducted among predominantly white, female populations. The role of perceived stress management in moderating this relationship is unclear. This study investigated the relationship between perceived stress and dietary choices among a diverse sample of male and female college freshmen and assessed whether perceived ability to manage stress moderated this relationship. 613 students from a large, public university completed an online survey which assessed past week consumption of various foods and beverages (e.g. soda, fast food, fruits, vegetables), as well as perceived stress and ability to manage stress. Hierarchical linear regression examined the association between perceived stress and past week dietary choices, and the moderating effect of perceived ability to manage stress, controlling for demographic variables. Perceived stress was positively associated with past week soda, coffee, energy drink, salty snack, frozen food, and fast food consumption (pmoderated the relationship between stress and sweet snack consumption. Individuals who reported low ability to manage stress consumed greater amounts. Findings indicate greater stress is associated with poor dietary choices among college freshmen. The relationship between stress and sweet snack consumption was exacerbated among those who reported low ability to manage stress. It may be important for college nutrition education programs to focus on the relationship between stress and diet and promote effective stress management techniques. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Osredkar Joško

    2012-05-01

    Full Text Available The human organism is exposed to the influence of various forms of stress, either physical, psychological or chemical, which all have in common that they may adversely affect our body. A certain amount of stress is always present and somehow directs, promotes or inhibits the functioning of the human body. Unfortunately, we are now too many and too often exposed to excessive stress, which certainly has adverse consequences. This is especially true for a particular type of stress, called oxidative stress. All aerobic organisms are exposed to this type of stress because they produce energy by using oxygen. For this type of stress you could say that it is rather imperceptibly involved in our lives, as it becomes apparent only at the outbreak of certain diseases. Today we are well aware of the adverse impact of radicals, whose surplus is the main cause of oxidative stress. However, the key problem remains the detection of oxidative stress, which would allow us to undertake timely action and prevent outbreak of many diseases of our time. There are many factors that promote oxidative stress, among them are certainly a fast lifestyle and environmental pollution. The increase in oxidative stress can also trigger intense physical activity that is directly associated with an increased oxygen consumption and the resulting formation of free radicals. Considering generally positive attitude to physical activity, this fact may seem at first glance contradictory, but the finding has been confimed by several studies in active athletes. Training of a top athlete daily demands great physical effort, which is also reflected in the oxidative state of the organism. However, it should be noted that the top athletes in comparison with normal individuals have a different defense system, which can counteract the negative effects of oxidative stress. Quite the opposite is true for irregular or excessive physical activity to which the body is not adapted.

  13. Estimation of Stresses in a Dry Sand Layer Tested on Shaking Table

    Science.gov (United States)

    Sawicki, Andrzej; Kulczykowski, Marek; Jankowski, Robert

    2012-12-01

    Theoretical analysis of shaking table experiments, simulating earthquake response of a dry sand layer, is presented. The aim of such experiments is to study seismic-induced compaction of soil and resulting settlements. In order to determine the soil compaction, the cyclic stresses and strains should be calculated first. These stresses are caused by the cyclic horizontal acceleration at the base of soil layer, so it is important to determine the stress field as function of the base acceleration. It is particularly important for a proper interpretation of shaking table tests, where the base acceleration is controlled but the stresses are hard to measure, and they can only be deduced. Preliminary experiments have shown that small accelerations do not lead to essential settlements, whilst large accelerations cause some phenomena typical for limit states, including a visible appearance of slip lines. All these problems should be well understood for rational planning of experiments. The analysis of these problems is presented in this paper. First, some heuristic considerations about the dynamics of experimental system are presented. Then, the analysis of boundary conditions, expressed as resultants of respective stresses is shown. A particular form of boundary conditions has been chosen, which satisfies the macroscopic boundary conditions and the equilibrium equations. Then, some considerations are presented in order to obtain statically admissible stress field, which does not exceed the Coulomb-Mohr yield conditions. Such an approach leads to determination of the limit base accelerations, which do not cause the plastic state in soil. It was shown that larger accelerations lead to increase of the lateral stresses, and the respective method, which may replace complex plasticity analyses, is proposed. It is shown that it is the lateral stress coefficient K0 that controls the statically admissible stress field during the shaking table experiments.

  14. Work stress in radiologists. A pilot study.

    Science.gov (United States)

    Magnavita, N; Fileni, A; Magnavita, G; Mammi, F; Mirk, P; Roccia, K; Bergamaschi, A

    2008-04-01

    We studied occupational stress and its psychosocial effects in a sample of Italian radiologists and radiotherapists: Radiologists and radiotherapists attending two medical conferences were invited to complete a questionnaire comprising four sections investigating the risk of occupational stress (organisational discomfort, Karasek's Job Content Questionnaire, Siegrist's Effort-Reward Imbalance, Warr's Job Satisfaction) and four sections investigating the health effects of such stress (Goldberg's Anxiety and Depression Scales, General Health Questionnaire, Lifestyles Questionnaire). Radiologists and radiotherapists generally expressed high levels of control, reward and satisfaction. However, 38.5% complained of severe organisational discomfort, 24% reported job strain, 28% reported effort/reward imbalance and 25% were dissatisfied. Female radiologists and radiotherapists showed higher levels of organisational discomfort than their male colleagues. Younger and less experienced radiologists and radiotherapists had higher strain scores than their older and more experienced colleagues. A significant correlation was observed between stress predictors and the effects of stress on health, including depression and anxiety, psychological distress and unhealthy lifestyles. Radiologists and radiotherapists are exposed to major occupational stress factors, and a significant percentage of them suffer from workplace stress. A special effort is required to prevent this condition.

  15. Competitive ability, stress tolerance and plant interactions along stress gradients.

    Science.gov (United States)

    Qi, Man; Sun, Tao; Xue, SuFeng; Yang, Wei; Shao, DongDong; Martínez-López, Javier

    2018-04-01

    Exceptions to the generality of the stress-gradient hypothesis (SGH) may be reconciled by considering species-specific traits and stress tolerance strategies. Studies have tested stress tolerance and competitive ability in mediating interaction outcomes, but few have incorporated this to predict how species interactions shift between competition and facilitation along stress gradients. We used field surveys, salt tolerance and competition experiments to develop a predictive model interspecific interaction shifts across salinity stress gradients. Field survey and greenhouse tolerance tests revealed tradeoffs between stress tolerance and competitive ability. Modeling showed that along salinity gradients, (1) plant interactions shifted from competition to facilitation at high salinities within the physiological limits of salt-intolerant plants, (2) facilitation collapsed when salinity stress exceeded the physiological tolerance of salt-intolerant plants, and (3) neighbor removal experiments overestimate interspecific facilitation by including intraspecific effects. A community-level field experiment, suggested that (1) species interactions are competitive in benign and, facilitative in harsh condition, but fuzzy under medium environmental stress due to niche differences of species and weak stress amelioration, and (2) the SGH works on strong but not weak stress gradients, so SGH confusion arises when it is applied across questionable stress gradients. Our study clarifies how species interactions vary along stress gradients. Moving forward, focusing on SGH applications rather than exceptions on weak or nonexistent gradients would be most productive. © 2018 by the Ecological Society of America.

  16. Individual differences in the effects of chronic stress on memory: behavioral and neurochemical correlates of resiliency.

    Science.gov (United States)

    Sweis, B M; Veverka, K K; Dhillon, E S; Urban, J H; Lucas, L R

    2013-08-29

    Chronic stress has been shown to impair memory, however, the extent to which memory can be impaired is often variable across individuals. Predisposed differences in particular traits, such as anxiety, may reveal underlying neurobiological mechanisms that could be driving individual differences in sensitivity to stress and, thus, stress resiliency. Such pre-morbid characteristics may serve as early indicators of susceptibility to stress. Neuropeptide Y (NPY) and enkephalin (ENK) are neurochemical messengers of interest implicated in modulating anxiety and motivation circuitry; however, little is known about how these neuropeptides interact with stress resiliency and memory. In this experiment, adult male rats were appetitively trained to locate sugar rewards in a motivation-based spatial memory task before undergoing repeated immobilization stress and then being tested for memory retention. Anxiety-related behaviors, among other characteristics, were monitored longitudinally. Results indicated that stressed animals which showed little to no impairments in memory post-stress (i.e., the more stress-resilient individuals) exhibited lower anxiety levels prior to stress when compared to stressed animals that showed large deficits in memory (i.e., the more stress-susceptible individuals). Interestingly, all stressed animals, regardless of memory change, showed reduced body weight gain as well as thymic involution, suggesting that the effects of stress on metabolism and the immune system were dissociated from the effects of stress on higher cognition, and that stress resiliency seems to be domain-specific rather than a global characteristic within an individual. Neurochemical analyses revealed that NPY in the hypothalamus and amygdala and ENK in the nucleus accumbens were modulated differentially between stress-resilient and stress-susceptible individuals, with elevated expression of these neuropeptides fostering anxiolytic and pro-motivation function, thus driving

  17. Stress urinary incontinence in the female

    International Nuclear Information System (INIS)

    Baldelli, S.; Giovagnoni, A.; Bichi Secchi, E.; Argaglia, G.; Caraceni, E.; Muzzonigro, G.

    1988-01-01

    This work is aimed at demonstrating the validity of conventional radiological procedures, correlated with urodynamics, in the study of female urinary stress incontinence. In a study population of 110 patients with a clinical-urodynamic diagnosis of stress incontinence, radiological evaluation was performed by means of retrograde cystography, bead chain cystourethrography, and voiding cystourethrography. Radiographic findings were correlated with urodynamic data, and in particular with urethral pressure profile (fuctional lenght of the urethra, maximum closing pressure, maximum urethral pressure). In all patients the posterior urethro-vesical angle values were higher than 100 grade centigrades; moreover, a correlation was proven to exist between an increase in the angle of front urethral inclination, the lowering and mobility of the urethro-vesical junction, and the severeness of urodynamic findings. Furtheremore, in the different stages of urodynamic severeness, urethral funnelling was most frequent, and the flattening of the posterior vesical floor in voiding cystourethrography. The high reliability of the radiographic findings, although obtained by means of conventional techniques, and the variability of the morphodynamic results confirm the importance of a combined radiographic and urodynamic study in the evaluation of stress incontinence

  18. Correlation between Kind of Delivery and Posttraumatic Stress ...

    African Journals Online (AJOL)

    2017 Annals of Medical and Health Sciences Research ... Background: Posttraumatic stress disorder (PTSD) is a very common mental ... in women with poor social support after delivery than in those enjoying a ... effect on the infant's cognitive development. ..... the mother receives at home and at work from her family and.

  19. Spirituality and stress management in healthy adults.

    Science.gov (United States)

    Tuck, Inez; Alleyne, Renee; Thinganjana, Wantana

    2006-12-01

    The purposes of this longitudinal, descriptive pilot study were to (a) test the acceptability and feasibility of a 6-week spiritual intervention; (b) determine the relationship between spirituality and stress; (c) explore the effects of the intervention on measures of perceived stress, spiritual perspective, and spiritual well-being; and (d) explore the meaning of spirituality. The sample consisted of 27 community-dwelling adults. Six categories emerged from the qualitative data as descriptors of the meaning and significance of spirituality. The survey data indicated that there were significant negative correlations between perceived stress and spiritual well-being at three time intervals, a significant decline in the levels of perceived stress, and a significant increase in spiritual perspective from the pretest to the 6-week follow-up. There were no significant changes in spiritual well-being. The intervention proved effective in reducing stress in this healthy adult sample.

  20. Residual stresses and stress corrosion cracking in pipe fittings

    International Nuclear Information System (INIS)

    Parrington, R.J.; Scott, J.J.; Torres, F.

    1994-06-01

    Residual stresses can play a key role in the SCC performance of susceptible materials in PWR primary water applications. Residual stresses are stresses stored within the metal that develop during deformation and persist in the absence of external forces or temperature gradients. Sources of residual stresses in pipe fittings include fabrication processes, installation and welding. There are a number of methods to characterize the magnitude and orientation of residual stresses. These include numerical analysis, chemical cracking tests, and measurement (e.g., X-ray diffraction, neutron diffraction, strain gage/hole drilling, strain gage/trepanning, strain gage/section and layer removal, and acoustics). This paper presents 400 C steam SCC test results demonstrating that residual stresses in as-fabricated Alloy 600 pipe fittings are sufficient to induce SCC. Residual stresses present in as-fabricated pipe fittings are characterized by chemical cracking tests (stainless steel fittings tested in boiling magnesium chloride solution) and by the sectioning and layer removal (SLR) technique

  1. Coping with organizational stress among hospital nurses in Southern Ontario.

    Science.gov (United States)

    Tyson, Paul D; Pongruengphant, Rana; Aggarwal, Bela

    2002-05-01

    Government cutbacks and anticipated staff reductions were hypothesized to be a unique source of organizational stress. The study focused on how nurses coped with stress and whether any strategy effectively reduced occupational stress. A sample of 107 nurses were asked to rate their occupational stress, job satisfaction, and coping strategies. Avoidance and social support were found to be significantly correlated with stress, but neither of these coping strategies appeared to reduce nurses' level of organizational stress. However, an interaction between problem solving and job satisfaction was found to be highly significant and it added 42% to predicting stress levels. Supporting the stress-buffering hypothesis, nurses with lower intrinsic job satisfaction seemed to benefit from employing problem solving as a coping strategy whereas dissatisfied nurses who infrequently use problem solving reported the highest levels of organizational stress. Paradoxically, intrinsically satisfied nurses who most frequently utilize problem solving experienced heightened organizational stress.

  2. Anticipated debt and financial stress in medical students.

    Science.gov (United States)

    Morra, Dante J; Regehr, Glenn; Ginsburg, Shiphra

    2008-01-01

    While medical student debt is increasing, the effect of debt on student well-being and performance remains unclear. As a part of a larger study examining medical student views of their future profession, data were collected to examine the role that current and anticipated debt has in predicting stress among medical students. A survey was administered to medical students in all four years at the University of Toronto. Of the 804 potential respondents across the four years of training, 549 surveys had sufficient data for inclusion in this analysis, for a response rate of 68%. Through multiple regression analysis, we evaluated the correlation between current and anticipated debt and financial stress. Although perceived financial stress correlates with both current and anticipated debt levels, anticipated debt was able to account for an additional 11.5% of variance in reported stress when compared to current debt levels alone. This study demonstrates a relationship between perceived financial stress and debt levels, and suggests that anticipated debt levels might be a more robust metric to capture financial burden, as it standardizes for year of training and captures future financial liabilities (future tuition and other future expenses).

  3. Stress og aldring

    DEFF Research Database (Denmark)

    Jørgensen, Anders; Jørgensen, Martin Balslev; Poulsen, Henrik Enghusen

    2012-01-01

    Accumulating evidence supports the popular notion that psychological stress states may accelerate aging. Stress has been shown to influence cellular systems known to be involved in the aging process. Furthermore, stress is associated with an increased risk of various age-related medical disorders....... These effects are likely mediated by the secretion of stress hormones. In this short review we focus on biochemical and epidemiological evidence for a link between stress and aging.......Accumulating evidence supports the popular notion that psychological stress states may accelerate aging. Stress has been shown to influence cellular systems known to be involved in the aging process. Furthermore, stress is associated with an increased risk of various age-related medical disorders...

  4. Changing stress levels through gaining information on stress

    Directory of Open Access Journals (Sweden)

    S.N. Madu

    2002-09-01

    Full Text Available Objective: The aim of this research was to find out the effect of the Information Phase of a Stress Management Program (SMP on the perceptions of participants about their stress levels. Method: A total sample of 100 workers (nursing staff, private business men and women, laboratory assistants, the protective services [foreman and security staff], as well as people in human resources departments took part in this study. All the participants were from the Northern and Gauteng Provinces in South Africa. The Combined Hassles and Uplifts Scale (Folkman & Lazarus, 1989 was used as an instrument to measure the perceived stress level of participants in a SMP. Result: A significant reduction in stress levels was achieved among those who received the Information Phase of the SMP only, as well as those who received the whole stress management techniques. There was no significant difference between the amount of reduction in perceived stress-levels achieved among those that received the Information Phase of the SMP only, compared to that of those who received the whole techniques. Conclusion: The authors conclude that where the resources are limited, only the information phase of a SMP may be given to desiring clients. That should help to save time and money spent on participating in SMPs. This should however not discourage the use of the whole SPM, where affordable. Keywords: Stress Management Programs, Information Phase, Perception, Stress Level.

  5. The prevalence and correlates of depression, anxiety, and stress in a sample of college students.

    Science.gov (United States)

    Beiter, R; Nash, R; McCrady, M; Rhoades, D; Linscomb, M; Clarahan, M; Sammut, S

    2015-03-01

    Over the past four years, the Franciscan University Counseling Center has reported a 231% increase in yearly visits, as well as a 173% increase in total yearly clients. This trend has been observed at many universities as mental health issues pose significant problems for many college students. The objective of this study was to investigate potential correlates of depression, anxiety, and stress in a sample of college students. The final analyzed sample consisted of 374 undergraduate students between the ages of 18 and 24 attending Franciscan University, Steubenville, Ohio. Subjects completed a survey consisting of demographic questions, a section instructing participants to rate the level of concern associated with challenges pertinent to daily life (e.g. academics, family, sleep), and the 21 question version of the Depression Anxiety Stress Scale (DASS21). The results indicated that the top three concerns were academic performance, pressure to succeed, and post-graduation plans. Demographically, the most stressed, anxious, and depressed students were transfers, upperclassmen, and those living off-campus. With the propensity for mental health issues to hinder the success of college students, it is vital that colleges continually evaluate the mental health of their students and tailor treatment programs to specifically target their needs. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Operational Stress and Correlates of Mental Health Among Joint Task Force Guantanamo Bay Military Personnel.

    Science.gov (United States)

    Webb-Murphy, Jennifer A; De La Rosa, Gabriel M; Schmitz, Kimberly J; Vishnyak, Elizabeth J; Raducha, Stephanie C; Roesch, Scott C; Johnston, Scott L

    2015-12-01

    Military personnel deployed to Joint Task Force Guantanamo Bay (JTF-GTMO) faced numerous occupational stressors. As part of a program evaluation, personnel working at JTF-GTMO completed several validated self-report measures. Personnel were at the beginning, middle, or end of their deployment phase. This study presents data regarding symptoms of posttraumatic stress disorder, alcohol abuse, depression, and resilience among 498 U.S. military personnel deployed to JTF-GTMO in 2009. We also investigated individual and organizational correlates of mental health among these personnel. Findings indicated that tenure at JTF-GTMO was positively related to adverse mental health outcomes. Regression models including these variables had R2 values ranging from .02 to .11. Occupation at JTF-GTMO also related to mental health such that guards reported poorer mental health than medical staff. Reluctance to seek out mental health care was also related to mental health outcomes. Those who reported being most reluctant to seek out care tended to report poorer mental health than those who were more willing to seek out care. Results suggested that the JTF-GTMO deployment was associated with significant psychological stress, and that both job-related and attitude-related variables were important to understanding mental health symptoms in this sample. Copyright © 2015 International Society for Traumatic Stress Studies.

  7. Negative relationship behavior is more important than positive: Correlates of outcomes during stressful life events.

    Science.gov (United States)

    Rivers, Alannah Shelby; Sanford, Keith

    2018-04-01

    When people who are married or cohabiting face stressful life situations, their ability to cope may be associated with two separate dimensions of interpersonal behavior: positive and negative. These behaviors can be assessed with the Couple Resilience Inventory (CRI). It was expected that scales on this instrument would correlate with outcome variables regarding life well-being, stress, and relationship satisfaction. It was also expected that effects for negative behavior would be larger than effects for positive and that the effects might be curvilinear. Study 1 included 325 married or cohabiting people currently experiencing nonmedical major life stressors and Study 2 included 154 married or cohabiting people with current, serious medical conditions. All participants completed an online questionnaire including the CRI along with an alternate measure of couple behavior (to confirm scale validity), a measure of general coping style (to serve as a covariate), and measures of outcome variables regarding well-being, quality of life, perceived stress, and relationship satisfaction. The effects for negative behavior were larger than effects for positive in predicting most outcomes, and many effects were curvilinear. Notably, results remained significant after controlling for general coping style, and scales measuring positive and negative behavior demonstrated comparable levels of validity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  8. Analysis of Brassica oleracea early stage abiotic stress responses reveals tolerance in multiple crop types and for multiple sources of stress.

    Science.gov (United States)

    Beacham, Andrew M; Hand, Paul; Pink, David Ac; Monaghan, James M

    2017-12-01

    Brassica oleracea includes a number of important crop types such as cabbage, cauliflower, broccoli and kale. Current climate conditions and weather patterns are causing significant losses in these crops, meaning that new cultivars with improved tolerance of one or more abiotic stress types must be sought. In this study, genetically fixed B. oleracea lines belonging to a Diversity Fixed Foundation Set (DFFS) were assayed for their response to seedling stage-imposed drought, flood, salinity, heat and cold stress. Significant (P ≤ 0.05) variation in stress tolerance response was found for each stress, for each of four measured variables (relative fresh weight, relative dry weight, relative leaf number and relative plant height). Lines tolerant to multiple stresses were found to belong to several different crop types. There was no overall correlation between the responses to the different stresses. Abiotic stress tolerance was identified in multiple B. oleracea crop types, with some lines exhibiting resistance to multiple stresses. For each stress, no one crop type appeared significantly more or less tolerant than others. The results are promising for the development of more environmentally robust lines of different B. oleracea crops by identifying tolerant material and highlighting the relationship between responses to different stresses. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. Stressors, Appraisal of Stressors, Experienced Stress and Cardiac Response: A Real-Time, Real-Life Investigation of Work Stress in Nurses.

    Science.gov (United States)

    Johnston, Derek; Bell, Cheryl; Jones, Martyn; Farquharson, Barbara; Allan, Julia; Schofield, Patricia; Ricketts, Ian; Johnston, Marie

    2016-04-01

    Stress in health care professionals may reflect both the work and appraisal of work and impacts on the individuals, their patients, colleagues and managers. The purpose of the present study is to examine physiological and psychological effects of stressors (tasks) and theory-based perceptions of work stressors within and between nurses in real time. During two work shifts, 100 nurses rated experienced stress, affect, fatigue, theory-based measures of work stress and nursing tasks on electronic diaries every 90 min, whereas heart rate and activity were measured continuously. Heart rate was associated with both demand and effort. Experienced stress was related to demand, control, effort and reward. Effort and reward interacted as predicted (but only within people). Results were unchanged when allowance was made for work tasks. Real-time appraisals were more important than actual tasks in predicting both psychological and physiological correlates of stress. At times when effort was high, perceived reward reduced stress.

  10. STRESS INDUCED OBESITY: LESSONS FROM RODENT MODELS OF STRESS

    Directory of Open Access Journals (Sweden)

    Zachary Robert Patterson

    2013-07-01

    Full Text Available Stress is defined as the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA axis. When an organism encounters a stressor (social, physical, etc., these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and loose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further our understanding of stress

  11. A Quantitative Study Examining Teacher Stress, Burnout, and Self-Efficacy

    Science.gov (United States)

    Stephenson, Timar D.

    2012-01-01

    The purpose of this quantitative, correlational study was to examine the relationships between stress, burnout, and self-efficacy in public school teachers in the Turks and Caicos Islands. The Teacher Stress Inventory was used to collect data on teacher stress, the Maslach Burnout Inventory Educators Survey was used to obtain data on teacher…

  12. Moving through the stressed genome: Emerging regulatory roles for transposons in plant stress tolerance

    Directory of Open Access Journals (Sweden)

    Negi Pooja

    2016-10-01

    Full Text Available The recognition of a positive correlation between organism genome size with its transposable element (TE content, represents a key discovery of the field of genome biology. Considerable evidence accumulated since then suggests the involvement of TEs in genome structure, evolution and function. The global genome reorganization brought about by transposon activity might play an adaptive/regulatory role in the host response to environmental challenges, reminiscent of McClintock’s original ’Controlling Element’ hypothesis. This regulatory aspect of TEs is also garnering support in light of the recent evidences which project TEs as distributed genomic control modules. According to this view, TEs are capable of actively reprogramming host genes circuits and ultimately fine-tuning the host response to specific environmental stimuli. Moreover, the stress-induced changes in epigenetic status of TE activity may allow TEs to propagate their stress responsive elements to host genes; the resulting genome fluidity can permit phenotypic plasticity and adaptation to stress. Given their predominating presence in the plant genomes, nested organization in the genic regions and potential regulatory role in stress response, TEs hold unexplored potential for crop improvement programs. This review intends to present the current information about the roles played by TEs in plant genome organization, evolution and function, and highlight the regulatory mechanisms in plant stress responses. We will also briefly discuss the connection between TE activity, host epigenetic response and phenotypic plasticity as a critical link for traversing the translational bridge from a purely basic study of TEs, to the applied field of stress adaptation and crop improvement.

  13. Moving through the Stressed Genome: Emerging Regulatory Roles for Transposons in Plant Stress Response.

    Science.gov (United States)

    Negi, Pooja; Rai, Archana N; Suprasanna, Penna

    2016-01-01

    The recognition of a positive correlation between organism genome size with its transposable element (TE) content, represents a key discovery of the field of genome biology. Considerable evidence accumulated since then suggests the involvement of TEs in genome structure, evolution and function. The global genome reorganization brought about by transposon activity might play an adaptive/regulatory role in the host response to environmental challenges, reminiscent of McClintock's original 'Controlling Element' hypothesis. This regulatory aspect of TEs is also garnering support in light of the recent evidences, which project TEs as "distributed genomic control modules." According to this view, TEs are capable of actively reprogramming host genes circuits and ultimately fine-tuning the host response to specific environmental stimuli. Moreover, the stress-induced changes in epigenetic status of TE activity may allow TEs to propagate their stress responsive elements to host genes; the resulting genome fluidity can permit phenotypic plasticity and adaptation to stress. Given their predominating presence in the plant genomes, nested organization in the genic regions and potential regulatory role in stress response, TEs hold unexplored potential for crop improvement programs. This review intends to present the current information about the roles played by TEs in plant genome organization, evolution, and function and highlight the regulatory mechanisms in plant stress responses. We will also briefly discuss the connection between TE activity, host epigenetic response and phenotypic plasticity as a critical link for traversing the translational bridge from a purely basic study of TEs, to the applied field of stress adaptation and crop improvement.

  14. Moving through the Stressed Genome: Emerging Regulatory Roles for Transposons in Plant Stress Response

    Science.gov (United States)

    Negi, Pooja; Rai, Archana N.; Suprasanna, Penna

    2016-01-01

    The recognition of a positive correlation between organism genome size with its transposable element (TE) content, represents a key discovery of the field of genome biology. Considerable evidence accumulated since then suggests the involvement of TEs in genome structure, evolution and function. The global genome reorganization brought about by transposon activity might play an adaptive/regulatory role in the host response to environmental challenges, reminiscent of McClintock's original ‘Controlling Element’ hypothesis. This regulatory aspect of TEs is also garnering support in light of the recent evidences, which project TEs as “distributed genomic control modules.” According to this view, TEs are capable of actively reprogramming host genes circuits and ultimately fine-tuning the host response to specific environmental stimuli. Moreover, the stress-induced changes in epigenetic status of TE activity may allow TEs to propagate their stress responsive elements to host genes; the resulting genome fluidity can permit phenotypic plasticity and adaptation to stress. Given their predominating presence in the plant genomes, nested organization in the genic regions and potential regulatory role in stress response, TEs hold unexplored potential for crop improvement programs. This review intends to present the current information about the roles played by TEs in plant genome organization, evolution, and function and highlight the regulatory mechanisms in plant stress responses. We will also briefly discuss the connection between TE activity, host epigenetic response and phenotypic plasticity as a critical link for traversing the translational bridge from a purely basic study of TEs, to the applied field of stress adaptation and crop improvement. PMID:27777577

  15. Symposium on teacher stress. Occupational stress among vocational teachers.

    Science.gov (United States)

    Pithers, R T; Fogarty, G J

    1995-03-01

    There is a widespread belief that work related stress among teachers is serious, with implications for teachers' health status and performance. The difficulty with interpreting data on teacher stress is that the measuring instruments used are often neither standardised nor sometimes focused on stressors pertinent to the occupational roles of teachers. This study, therefore, uses a recently developed test instrument called the Occupational Stress Inventory (OSI) which concisely measures occupational stress, strain and coping resources. Data were obtained, using the OSI, from a group of vocational teachers and compared to a group of professional non-teachers. Overall the results showed a significantly higher level of teacher stress, although only one of 10 stress and strain measures contributed to this effect. The implications for teachers, in terms of occupational role, are discussed.

  16. When does stress help or harm? The effects of stress controllability and subjective stress response on stroop performance.

    Science.gov (United States)

    Henderson, Roselinde K; Snyder, Hannah R; Gupta, Tina; Banich, Marie T

    2012-01-01

    The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding tasks. In addition, research suggests that the impact of stress on cognitive functioning depends on an individual's response to stressors: moderate responses to stress can lead to improved performance while extreme (high or low) responses can lead to impaired performance. The present studies tested the hypothesis that (1) learning to behaviorally control stressors leads to improved performance on a test of general executive functioning, the color-word Stroop, and that (2) this improvement emerges specifically for people who report moderate (subjective) responses to stress. Experiment 1: Stroop performance, measured before and after a stress manipulation, was compared across groups of undergraduate participants (n = 109). People who learned to control a noise stressor and received accurate performance feedback demonstrated reduced Stroop interference compared with people exposed to uncontrollable noise stress and feedback indicating an exaggerated rate of failure. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest reduction in Stroop interference. In contrast, in the group exposed to uncontrollable events, self-reported stress failed to predict performance. Experiment 2: In a second sample (n = 90), we specifically investigated the role of controllability by keeping the rate of failure feedback constant across groups. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest Stroop

  17. Evaluation of association between psychological stress and serum cortisol levels in patients with chronic periodontitis - Estimation of relationship between psychological stress and periodontal status.

    Science.gov (United States)

    Jaiswal, Roshni; Shenoy, Nina; Thomas, Biju

    2016-01-01

    Stress classically describes a destructive notion that can have a bearing on one's physical and mental health. It may also add to an increased propensity to periodontal disease. To investigate the association between psychological stress and serum cortisol levels in patients with chronic periodontitis. Forty subjects were recruited from the outpatient department at the Department of Periodontics, from a college in Mangalore, divided into two groups, i.e., twenty as healthy controls and twenty were stressed subjects with chronic periodontitis. The clinical examination included the assessment of probing pocket depth, clinical attachment level and oral hygiene index-simplified. Serum cortisol levels were estimated biochemically using the enzyme-linked immunosorbent assay method and the estimation of psychological stress was done by a questionnaire. Descriptive statistics such as mean and standard deviation was used to review the collected data. Independent sample t -test was used for comparison and correlation was evaluation using Pearson's correlation test. As per our observation, high serum cortisol levels and psychological stress are positively linked with chronic periodontitis establishing a risk profile showing a significant correlation ( P periodontitis patients as it should be considered as an imperative risk factor for periodontal disease.

  18. Coping with stress and by stress: Russian men and women talking about transition, stress and health.

    Science.gov (United States)

    Pietilä, Ilkka; Rytkönen, Marja

    2008-01-01

    Several studies have claimed stress to be a major reason for poor public health in Russia and referred to significant social changes as a reason for the high level of perceived stress among Russians. This article aims to examine how stress and its relation to health are interpreted in the context of everyday life in Russian men's and women's interview talk with a focus on descriptions of recent social changes. The research material consists of 29 thematic interviews of men and women from St. Petersburg aged 15-81. In the analysis of contextual constructions of stress, we found that stress was used not only within a context of an individual's own life as an expression of a strained psycho-physiological state but also denoted larger societal processes and changes. In addition to individual experiences, the whole of Russian society was described as suffering from stress. Throughout the material, most interviewees, whilst outspokenly blaming stress for deteriorating physical health, met difficulties in making concrete these negative influences. Based on analysis, we interpret our interviewees' accounts of stress as a part of the cultural discourse wherein 'stress' serves as a conceptual tool in making interpretations about both the people and their social environment. Stress, as a concept, has emerged in a wide range of different institutional sites, such as the media and public health policy and has become a discursive entity of contemporary social life in Russia. We claim that it has simultaneously become an intermediary concept articulating a shared, cultural experience of the changes in Russian society and their effects on individuals' everyday life and health. Thus, the concept of stress helps people to articulate, make sensible, and cope with the impacts of transition on their individual lives.

  19. Correlation among academic stress, academic burnout, and academic performance in nursing and paramedic students of Qom University of Medical Sciences, Iran

    OpenAIRE

    hamid Asayesh; Fatemeh Sharififard; Mojtaba Mosavi; Zahra Taheri Kharameh; Zahra Aliakbarzade Arani; Alireza Shouri Bidgoli

    2016-01-01

    Background and Objectives: Learning is a stressful experience of human life; reduced adaption to stressors causes academic burnout which is a reason for academic failure among students. This study investigated the correlation among academic stress, academic burnout, and academic performance in nursing and paramedic students of Qom University of Medical Sciences. Methods: In this descriptive, cross-sectional study, 264 nursing and paramedic students were randomly selected. Demographic ch...

  20. Perceived work-related stress and early atherosclerotic changes in healthy employees.

    Science.gov (United States)

    Bugajska, Joanna; Widerszal-Bazyl, Maria; Radkiewicz, Piotr; Pasierski, Tomasz; Szulczyk, Grazyna Anna; Zabek, Jakub; Wojciechowska, Bozena; Jedryka-Góral, Anna

    2008-08-01

    This study was conducted to investigate the relationship between perceived work-related stress and preclinical atherosclerosis. A total of 100 managers and 50 office workers aged 35-65 participated in a questionnaire study. Individual, family and work-related stress risk factors and coping were evaluated in all the studied individuals. Serum levels of biochemical (total cholesterol, LDL, HDL, TG, glucose) and serological risk factors of atherosclerosis (anticardiolipin, anti-beta(2) GPI, anti-oxLDL, anti-HSP and anti-hsCRP antibodies) were evaluated. A computer analysis of B-mode ultrasound images was used to assess carotid artery intima-media thickness (IMT) and atherosclerotic plaque in carotid arteries. Statistical analysis was conducted with SPSS v. 11.5. The studied individuals showed average ranges of both the global stress level and of coping results. In 71% no changes were found in the ultrasound image and in 29% of individuals (43) the presence of plaque was shown. The mean value of the IMT measure was 0.0618 +/- 0.013 mm. IMT and plaque correlated negatively with the level of global work-related stress (r = -0.26; P related stress and coping, or between coping and IMT (P > 0.05), or between work-related stress and healthy lifestyle (no smoking, no excessive use of alcohol, high physical activity), or between healthy lifestyle and IMT (P > 0.05). Positive correlation between IMT and LDL and smoking did not result from higher stress reaction in the studied individuals. The explanation of the negative correlation between perceived work-related stress and preclinical atherosclerosis was not confirmed either by the subjects under high stress undertaking healthy protective activities or by their escaping into unhealthy behaviour. The most probable interpretation of the results is that in individuals with a low level of perceived work-related stress, somatization of stress takes place.

  1. Representative stresses for creep deformation and failure of pressurised tubes and pipes

    International Nuclear Information System (INIS)

    Cane, B.J.; Browne, R.J.

    1982-01-01

    Results of a series of tube and uniaxial tests on two casts of 1/2CrMoV pipe steel are examined to determine the representative stress which must be applied to uniaxial data in order to predict the strain rates and lives of pressurised tubes and pipes. The stress criterion for deformation is shown to correlate with the analytically derived reference stress (σsub(R)) at low pressure while at high pressures a modified reference stress (> σsub(R)) must be used. The rupture life exhibits a similar correlation such that the representative stress for rupture is given by σsub(R) at low stresses yet, at high stresses, it is greater than σsub(R) and attains a value comparable with the mean diameter hoop stress. The latter thus describes the rupture life at high pressures but significantly underestimates the life at low pressures approaching those in service. Consideration is given to the multiaxial stress rupture criterion and the effect of geometry in constant load tests. (author)

  2. Age-Related Decrease in Stress Responsiveness and Proactive Coping in Male Mice.

    Science.gov (United States)

    Oh, Hee-Jin; Song, Minah; Kim, Young Ki; Bae, Jae Ryong; Cha, Seung-Yun; Bae, Ji Young; Kim, Yeongmin; You, Minsu; Lee, Younpyo; Shim, Jieun; Maeng, Sungho

    2018-01-01

    Coping is a strategic approach to dealing with stressful situations. Those who use proactive coping strategies tend to accept changes and act before changes are expected. In contrast, those who use reactive coping are less flexible and more likely to act in response to changes. However, little research has assessed how coping style changes with age. This study investigated age-related changes in coping strategies and stress responsiveness and the influence of age on the processing of conditioned fear memory in 2-, 12- and 23-month-old male mice. Coping strategy was measured by comparing the escape latency in an active avoidance test and by comparing responses to a shock prod. The results showed that proactivity in coping response gradually decreased with age. Stress responsiveness, measured by stress-induced concentration of corticosterone, was also highest in 2-month-old mice and decreased with age. Consolidation of fear memory was highest in 12-month-old mice and was negatively correlated with the degree of stress responsiveness and proactivity in coping. Fear extinction did not differ among age groups and was not correlated with stress responsiveness or the proactivity of coping. However, the maintenance of extinct fear memory, which was best in 2-month-old mice and worst in 12-month-old mice, was negatively correlated with stress responsiveness but not with coping style. Age-dependent changes in the expression of glucocorticoid receptor (GR) and its regulatory co-chaperones, which are accepted mechanisms for stress hormone stimulation, were measured in the hippocampus. The expression of GR was increased at 12 months compared to other age groups. There were no differences in Hsp70 and BAG1 expression by age. These results can be summarized as follows: (1) stress responsiveness and proactivity in coping decreased with age class; (2) consolidation of fear memory was negatively correlated with both stress responsiveness and proactivity; however, maintenance of

  3. Severe occupational hand eczema, job stress and cumulative sickness absence.

    Science.gov (United States)

    Böhm, D; Stock Gissendanner, S; Finkeldey, F; John, S M; Werfel, T; Diepgen, T L; Breuer, K

    2014-10-01

    Stress is known to activate or exacerbate dermatoses, but the relationships between chronic stress, job-related stress and sickness absence among occupational hand eczema (OHE) patients are inadequately understood. To see whether chronic stress or burnout symptoms were associated with cumulative sickness absence in patients with OHE and to determine which factors predicted sickness absence in a model including measures of job-related and chronic stress. We investigated correlations of these factors in employed adult inpatients with a history of sickness absence due to OHE in a retrospective cross-sectional explorative study, which assessed chronic stress (Trier Inventory for the Assessment of Chronic Stress), burnout (Shirom Melamed Burnout Measure), clinical symptom severity (Osnabrück Hand Eczema Severity Index), perceived symptom severity, demographic characteristics and cumulative days of sickness absence. The study group consisted of 122 patients. OHE symptoms were not more severe among patients experiencing greater stress and burnout. Women reported higher levels of chronic stress on some measures. Cumulative days of sickness absence correlated with individual dimensions of job-related stress and, in multiple regression analysis, with an overall measure of chronic stress. Chronic stress is an additional factor predicting cumulative sickness absence among severely affected OHE patients. Other relevant factors for this study sample included the 'cognitive weariness' subscale of the Shirom Melamed Burnout Measure and the physical component summary score of the SF-36, a measure of health-related life quality. Prevention and rehabilitation should take job stress into consideration in multidisciplinary treatment strategies for severely affected OHE patients. © The Author 2014. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Stress relaxation characteristics of type 304 stainless steel

    International Nuclear Information System (INIS)

    Manjoine, M.J.

    1975-01-01

    The stress relaxation of type 304 stainless steel below 900 0 F (482 0 C) is practically time independent after 100 h and has a maximum of about 18 per cent. The per cent relaxation decreases with increasing degree of cold work and with decreasing stress. Above 900 0 F the per cent relaxation increases with time, temperature, and cold work. The initial stress can also be increased for cold work materials so that the remaining stress can be maintained at a higher value even up to 1200 0 F (649 0 C). Time-temperature parameters are practical to correlate and extrapolate the data in the higher temperature range. (author)

  5. Stress Fractures

    Science.gov (United States)

    Stress fractures Overview Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of ...

  6. Local yield stress statistics in model amorphous solids

    Science.gov (United States)

    Barbot, Armand; Lerbinger, Matthias; Hernandez-Garcia, Anier; García-García, Reinaldo; Falk, Michael L.; Vandembroucq, Damien; Patinet, Sylvain

    2018-03-01

    We develop and extend a method presented by Patinet, Vandembroucq, and Falk [Phys. Rev. Lett. 117, 045501 (2016), 10.1103/PhysRevLett.117.045501] to compute the local yield stresses at the atomic scale in model two-dimensional Lennard-Jones glasses produced via differing quench protocols. This technique allows us to sample the plastic rearrangements in a nonperturbative manner for different loading directions on a well-controlled length scale. Plastic activity upon shearing correlates strongly with the locations of low yield stresses in the quenched states. This correlation is higher in more structurally relaxed systems. The distribution of local yield stresses is also shown to strongly depend on the quench protocol: the more relaxed the glass, the higher the local plastic thresholds. Analysis of the magnitude of local plastic relaxations reveals that stress drops follow exponential distributions, justifying the hypothesis of an average characteristic amplitude often conjectured in mesoscopic or continuum models. The amplitude of the local plastic rearrangements increases on average with the yield stress, regardless of the system preparation. The local yield stress varies with the shear orientation tested and strongly correlates with the plastic rearrangement locations when the system is sheared correspondingly. It is thus argued that plastic rearrangements are the consequence of shear transformation zones encoded in the glass structure that possess weak slip planes along different orientations. Finally, we justify the length scale employed in this work and extract the yield threshold statistics as a function of the size of the probing zones. This method makes it possible to derive physically grounded models of plasticity for amorphous materials by directly revealing the relevant details of the shear transformation zones that mediate this process.

  7. Stress resiliency, psychological empowerment and conflict management styles among baccalaureate nursing students.

    Science.gov (United States)

    Pines, Eula W; Rauschhuber, Maureen L; Norgan, Gary H; Cook, Jennifer D; Canchola, Leticia; Richardson, Cynthia; Jones, Mary Elaine

    2012-07-01

    This article is a report of a Neuman Systems Model-guided correlational study of the relations of stress resiliency, psychological empowerment, selected demographic characteristics (age, ethnicity, semester in school) and conflict management styles. Emerging evidence suggests that stress resiliency and psychological empowerment can strengthen student nurses in academic achievement and coping with stress. Little is known about conflict management styles of students and the relationship to empowerment, resiliency and the implications for managing workplace conflict. A correlational study was conducted in Spring 2010 with 166 baccalaureate students. Most participants were female, single, Hispanic and 25 years old. The data collection instruments included the Stress Resiliency Profile, the Psychological Empowerment Instrument, the Conflict Mode Instrument and a demographic inventory. Descriptive and inferential correlational statistics were used to analyse the data. Students scored in the high range for focusing on their deficiencies in conflict situations; they scored above the 60th percentile for avoiding and accommodating behaviours and were less likely to use competing or collaborating strategies to manage conflict. Empowerment scores were significantly correlated with stress resiliency scores. Students with high scores on empowerment had high scores on the skill recognition subscale of the Stress Resiliency Profile suggesting more resilience; high scores on empowerment were related to high necessitating subscale scores of the Stress Resiliency Profile suggesting a predisposition to stress. Neuman Systems Model may provide guidance for educators to strengthen student nurses' management of stressors in the workplace. © 2011 Blackwell Publishing Ltd.

  8. Evaluation of association between psychological stress and serum cortisol levels in patients with chronic periodontitis - Estimation of relationship between psychological stress and periodontal status

    Directory of Open Access Journals (Sweden)

    Roshni Jaiswal

    2016-01-01

    Full Text Available Background: Stress classically describes a destructive notion that can have a bearing on one's physical and mental health. It may also add to an increased propensity to periodontal disease. Aim: To investigate the association between psychological stress and serum cortisol levels in patients with chronic periodontitis. Materials and Methods: Forty subjects were recruited from the outpatient department at the Department of Periodontics, from a college in Mangalore, divided into two groups, i.e., twenty as healthy controls and twenty were stressed subjects with chronic periodontitis. The clinical examination included the assessment of probing pocket depth, clinical attachment level and oral hygiene index-simplified. Serum cortisol levels were estimated biochemically using the enzyme-linked immunosorbent assay method and the estimation of psychological stress was done by a questionnaire. Results: Descriptive statistics such as mean and standard deviation was used to review the collected data. Independent sample t-test was used for comparison and correlation was evaluation using Pearson's correlation test. As per our observation, high serum cortisol levels and psychological stress are positively linked with chronic periodontitis establishing a risk profile showing a significant correlation (P < 0.05. Conclusion: Routine serum cortisol assessment may be a reasonable and a valuable investigative indicator to rule out stress in periodontitis patients as it should be considered as an imperative risk factor for periodontal disease.

  9. Extraversion and cardiovascular responses to recurrent social stress: Effect of stress intensity.

    Science.gov (United States)

    Lü, Wei; Xing, Wanying; Hughes, Brian M; Wang, Zhenhong

    2017-10-28

    The present study sought to establish whether the effects of extraversion on cardiovascular responses to recurrent social stress are contingent on stress intensity. A 2×5×1 mixed-factorial experiment was conducted, with social stress intensity as a between-subject variable, study phase as a within-subject variable, extraversion as a continuous independent variable, and cardiovascular parameter (HR, SBP, DBP, or RSA) as a dependent variable. Extraversion (NEO-FFI), subjective stress, and physiological stress were measured in 166 undergraduate students randomly assigned to undergo moderate (n=82) or high-intensity (n=84) social stress (a public speaking task with different levels of social evaluation). All participants underwent continuous physiological monitoring while facing two consecutive stress exposures distributed across five laboratory phases: baseline, stress exposure 1, post-stress 1, stress exposure 2, post-stress 2. Results indicated that under moderate-intensity social stress, participants higher on extraversion exhibited lesser HR reactivity to stress than participants lower on extraversion, while under high-intensity social stress, they exhibited greater HR, SBP, DBP and RSA reactivity. Under both moderate- and high-intensity social stress, participants higher on extraversion exhibited pronounced SBP and DBP response adaptation to repeated stress, and showed either better degree of HR recovery or greater amount of SBP and DBP recovery after stress. These findings suggest that individuals higher on extraversion exhibit physiological flexibility to cope with social challenges and benefit from adaptive cardiovascular responses. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. A crack opening stress equation for fatigue crack growth

    Science.gov (United States)

    Newman, J. C., Jr.

    1984-01-01

    A general crack opening stress equation is presented which may be used to correlate crack growth rate data for various materials and thicknesses, under constant amplitude loading, once the proper constraint factor has been determined. The constraint factor, alpha, is a constraint on tensile yielding; the material yields when the stress is equal to the product of alpha and sigma. Delta-K (LEFM) is plotted against rate for 2024-T3 aluminum alloy specimens 2.3 mm thick at various stress ratios. Delta-K sub eff was plotted against rate for the same data with alpha = 1.8; the rates correlate well within a factor of two.

  11. Evaluating Yield and Drought Stress Indices under End Season Drought Stress in Promising Genotypes of Barley

    Directory of Open Access Journals (Sweden)

    H. Tajalli

    2012-08-01

    Full Text Available To study the effects of end season drought stress on yield, yield components and drought stress indices in barley, a split plot experiment arranged in randomized complete block design with three replications was conducted at the Agricultural Research Center of Birjand in 2008-2009 crop years. Drought stress, in 2 levels, consists of control (complete irrigation and stopping irrigation at the 50% of heading stage, and 20 promising genotypes of barley were the treatments of the experiment. Results revealed that stopping irrigation lead to declining of 14.64 and 8.12 percent of seed and forage yields against control condition, respectively. Using stress susceptibility index (SSI indicated that genotypes 2, 3, 7, 9, 10 and 15; using STI and GMP indices, genotypes 5, 8, 18 and 20 using MP, genotypes 8, 18 and 20, and TOL, genotypes 2, 3, 7, 9, and 10, were the most drought tolerant genotypes. Correlation between seed yield and stress evaluation indices showed that MP, GMP and STI are the best indices to be used in selection and introducing drought tolerant genotypes of barley. Considering all indices, and given that the best genotypes are those with high yield under normal condition and minimum yield reduction under drought stress, No. 18 and 20 could be introduced as the most tolerant barley genotypes to drought.

  12. Work-related stress assessed by a text message single-item stress question.

    Science.gov (United States)

    Arapovic-Johansson, B; Wåhlin, C; Kwak, L; Björklund, C; Jensen, I

    2017-12-02

    Given the prevalence of work stress-related ill-health in the Western world, it is important to find cost-effective, easy-to-use and valid measures which can be used both in research and in practice. To examine the validity and reliability of the single-item stress question (SISQ), distributed weekly by short message service (SMS) and used for measurement of work-related stress. The convergent validity was assessed through associations between the SISQ and subscales of the Job Demand-Control-Support model, the Effort-Reward Imbalance model and scales measuring depression, exhaustion and sleep. The predictive validity was assessed using SISQ data collected through SMS. The reliability was analysed by the test-retest procedure. Correlations between the SISQ and all the subscales except for job strain and esteem reward were significant, ranging from -0.186 to 0.627. The SISQ could also predict sick leave, depression and exhaustion at 12-month follow-up. The analysis on reliability revealed a satisfactory stability with a weighted kappa between 0.804 and 0.868. The SISQ, administered through SMS, can be used for the screening of stress levels in a working population. © The Author 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  13. The Malay Version of the Perceived Stress Scale (PSS)-10 is a Reliable and Valid Measure for Stress among Nurses in Malaysia.

    Science.gov (United States)

    Sandhu, Sukhvinder Singh; Ismail, Noor Hassim; Rampal, Krishna Gopal

    2015-11-01

    The Perceived Stress Scale-10 (PSS-10) is widely used to assess stress perception. The aim of this study was to translate the original PSS-10 into Malay and assess the reliability and validity of the Malay version among nurses. The Malay version of the PSS-10 was distributed among 229 nurses from four government hospitals in Selangor State. Test-retest reliability and concurrent validity was conducted with 25 nurses with the Malay version of the Depression Anxiety Stress Scales (DASS) 21. Cronbach's alpha, confirmatory factor analysis (CFA), intraclass correlation coefficient and Pearson's r correlation coefficient were used to determine the psychometric properties of the Malay PSS-10. Two factor components were yielded through exploratory factor analysis with eigenvalues of 3.37 and 2.10, respectively. Both of the factors accounted for 54.6% of the variance. CFA yielded a two-factor structure with satisfactory goodness-of-fit indices [x 2 /df = 2.43; comparative fit index (CFI) = 0.92, goodness-of-fit Index (GFI) = 0.94; standardised root mean square residual (SRMR) = 0.07 and root mean square error of approximation (RMSEA) = 0.08 (90% CI = 0.07-0.09)]. The Cronbach's alpha coefficient for the total items was 0.63 (0.82 for factor 1 and 0.72 for factor 2). The intraclass correlation coefficient (ICC) was 0.81 (95% CI: 0.62-0.91) for test-retest reliability testing after seven days. The total score and the negative component of the PSS-10 correlated significantly with the stress component of the DASS-21: (r = 0.61, P < 0.001) and (r = 0.56, P < 0.004), respectively. The Malay version of the PSS-10 demonstrated a satisfactory level of validity and reliability to assess stress perception. Therefore, this questionnaire is valid in assessing stress perception among nurses in Malaysia.

  14. Background Stress Inventory: Developing a Measure of Understudied Stress.

    Science.gov (United States)

    Terrill, Alexandra L; Gjerde, Jill M; Garofalo, John P

    2015-10-01

    Background stress is an understudied source of stress that involves both ambient stress and daily hassles upon which new stressors are superimposed. To date, an accurate measure of the background stress construct has not been available. We developed the Background Stress Inventory, a 25-item self-report measure that asks respondents to indicate how distressed they have felt over the past month and the majority of the past year across five domains: financial, occupation, environment, health and social. Seven hundred seventy-two participants completed the paper-and-pencil measure; the sample was randomly split into two separate subsamples for analyses. Exploratory factor analysis suggested five factors corresponding to these domains, and confirmatory factor analysis showed acceptable global fit (X(2)(255) = 456.47, comparative fit index = 0.94, root mean square error of approximation = 0.045). Cronbach's alpha (0.89) indicated good internal reliability. Construct validity analyses showed significant positive relationships with measures of perceived stressfulness (r = 0.62) and daily hassles (0.41), p's < 0.01. Depressive symptoms (0.62) and basal blood pressure (0.21) were both significantly associated with background stress, p's < 0.01. The importance of the proposed measure is reflected in the limited research base on the impact of background stress. Systematic investigation of this measure will provide insight into this understudied form of chronic stress and its potential influence on both psychological and physical endpoints. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Elevated oxidative stress monitored via the albumin-thiol redox state is correlated with matrix metalloproteinase-3 elevation in patients with rheumatoid arthritis.

    Science.gov (United States)

    Kizaki, Kazuha; Yoshizumi, Yusuke; Takahashi, Teppei; Era, Seiichi

    2015-01-01

    In rheumatoid arthritis (RA), matrix metalloproteinase-3 (MMP-3) and oxidative stress contribute to joint destruction. However, little is known about the relationship between MMP-3 and oxidative stress in RA. We measured the albumin-thiol redox state as a marker of oxidative stress, MMP-3, and the DAS-28 score calculated using CRP values among forty-seven patients (9 males and 38 females) with RA. According to the serum MMP-3 levels, they were divided into two groups (group A: within normal ranges of 36.9-121.0 ng/mL for men and 17.3-59.7 ng/mL for women; group B: above normal ranges). The albumin-thiol redox state in group B was significantly oxidized compared with that in group A (p < 0.01). The percentage of oxidized albumin-thiol showed a positive correlation with serum MMP-3 (r = 0.52). DAS-28 and CRP were also correlated with the percentage of oxidized albumin-thiol (r = 0.46, r = 0.44). The albumin-thiol redox state was significantly oxidized in correlation with serum MMP-3 elevation in RA.

  16. Correlation between residual stress and plastic strain amplitude during low cycle fatigue of mechanically surface treated austenitic stainless steel AISI 304 and ferritic-pearlitic steel SAE 1045

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, I. [Institute of Materials Engineering, University of Kassel, 34125 Kassel, Hessen (Germany)], E-mail: Ivan.Nikitin@infineon.com; Besel, M. [Institute of Materials Engineering, University of Kassel, 34125 Kassel, Hessen (Germany)

    2008-09-15

    Mechanical surface treatments such as deep rolling are known to affect the near-surface microstructure and induce, e.g. residual stresses and/or increase the surface hardness. It is well known that, e.g. compressive residual stress states usually increase the lifetime under fatigue loading. The stress relaxation behaviour and the stability of the residual stress during fatigue loading depend on the mechanical surface treatment method. In this paper three different surface treatments are used and their effects on the low cycle fatigue behaviour of austenitic stainless steel (AISI 304) and ferritic-pearlitic steel (SAE 1045) are investigated. X-ray diffraction is applied for the non-destructive evaluation of the stress state and the microstructure. It is found that consecutive deep rolling and annealing as well as high temperature deep rolling produce more stable near-surface stress states than conventional deep rolling at room temperature. The plastic strain amplitudes during fatigue loading are measured and it is shown that they correlate well with the induced residual stress and its relaxation, respectively. Furthermore, Coffin-Manson plots are presented which clearly show the correlation between the plastic strain amplitude and the fatigue lifetime.

  17. Examining perceptions of academic stress and its sources among university students: The Perception of Academic Stress Scale

    Directory of Open Access Journals (Sweden)

    Dalia Bedewy

    2015-07-01

    Full Text Available The development of a scale to measure perceived sources of academic stress among university students. Based on empirical evidence and recent literature review, we developed an 18-item scale to measure perceptions of academic stress and its sources. Experts ( n  = 12 participated in the content validation process of the instrument before it was administered to ( n  = 100 students. The developed instrument has internal consistency reliability of 0.7 (Cronbach’s alpha, there was evidence for content validity, and factor analysis resulted in four correlated and theoretically meaningful factors. We developed and tested a scale to measure academic stress and its sources. This scale takes 5 minutes to complete.

  18. Stress and Health

    DEFF Research Database (Denmark)

    Rod, Naja Hulvej

    2014-01-01

    and behavioral mechanisms. Stress is a complex concept and in order to better understand the relation between stress and health, the dissertation works with a clear distinction between the health consequences of different types of stress including external stressors, perceived stress, and measures of the stress......’s disease patients. Results The combined evidence of this dissertation shows a moderately higher risk of some common chronic disorders including cardiovascular disease and atopic disorders among individuals exposed to work-related stressors and perceived stress. Most empirical studies also report higher...... of pathways. The physiological stress response has the ability to directly affect vital body systems including the cardiovascular, immune, and metabolic systems. Further, stress can lead to unfavorable changes in health-related behavior, impaired sleep and poor mental health. An increasing number of well...

  19. Depressed suicide attempters with posttraumatic stress disorder.

    Science.gov (United States)

    Ramberg, Maria; Stanley, Barbara; Ystgaard, Mette; Mehlum, Lars

    2015-01-01

    Posttraumatic stress disorder and major depressive disorder are well-established risk factors for suicidal behavior. This study compared depressed suicide attempters with and without comorbid posttraumatic stress disorder with respect to additional diagnoses, global functioning, depressive symptoms, substance abuse, history of traumatic exposure, and suicidal behavior. Adult patients consecutively admitted to a general hospital after a suicide attempt were interviewed and assessed for DSM-IV diagnosis and clinical correlates. Sixty-four patients (71%) were diagnosed with depression; of them, 21 patients (32%) had posttraumatic stress disorder. There were no group differences in social adjustment, depressive symptoms, or suicidal intent. However, the group with comorbid depression and posttraumatic stress disorder had more additional Axis I diagnoses, a higher degree of childhood trauma exposure, and more often reported previous suicide attempts, non-suicidal self-harm, and vengeful suicidal motives. These findings underline the clinical importance of diagnosis and treatment of posttraumatic stress disorder in suicide attempters.

  20. Relationships among Constitution, Stress, and Discomfort in the First Trimester

    Directory of Open Access Journals (Sweden)

    Hsiao-Ling Wang

    2012-01-01

    trimester of pregnancy. We adopted a descriptive and correlational research design and collected data from 261 pregnant women during their first trimester in southern Taiwan using structured questionnaires. Results showed that (1 stress was significantly and positively correlated with Yang-Xu, Yin-Xu, and Tan-Shi-Yu-Zhi constitutions, respectively; (2 Yin-Xu and Tan-Shi-Yu-Zhi constitutions had significant correlations with all symptoms of discomfort, while Yang-Xu had significant correlations with all symptoms of discomfort except for “running nose”; (3 Tan-Shi-Yu-Zhi constitution and stress were two indicators for “fatigue”; Tan-Shi-Yu-Zhi was the indicator for “nausea”; Yang-Xu and Yin-Xu were indicators for “frequent urination.” Our findings also indicate that stress level affects constitutional changes and that stress and constitutional change affect the incidence of discomfort. This research can help healthcare professionals observe these discomforts and provide individualized care for pregnant women, to nurture pregnant women into neutral-type constitution, minimize their levels of discomfort, and promote the health of the fetus and the mother.

  1. Correlation of transcriptomic responses and metal bioaccumulation in Mytilus edulis L. reveals early indicators of stress

    Energy Technology Data Exchange (ETDEWEB)

    Poynton, Helen C., E-mail: helen.poynton@umb.edu; Robinson, William E.; Blalock, Bonnie J.; Hannigan, Robyn E.

    2014-10-15

    Highlights: • Gene expression and metal tissue concentrations were compared in Mytilus edulis. • Expression levels of several transcripts correlated with metal concentrations. • Transcripts involved in the unfolded protein response (UPR) were induced. • Integration of transcriptomics and tissue levels provides insight to toxicity. - Abstract: Marine biomonitoring programs in the U.S. and Europe have historically relied on monitoring tissue concentrations of bivalves to monitor contaminant levels and ecosystem health. By integrating ‘omic methods with these tissue residue approaches we can uncover mechanistic insight to link tissue concentrations to potential toxic effects. In an effort to identify novel biomarkers and better understand the molecular toxicology of metal bioaccumulation in bivalves, we exposed the blue mussel, Mytilus edulis L., to sub-lethal concentrations (0.54 μM) of cadmium, lead, and a Cd + Pb mixture. Metal concentrations were measured in gill tissues at 1, 2, and 4 weeks, and increased linearly over the 4 week duration. In addition, there was evidence that Pb interfered with Cd uptake in the mixture treatment. Using a 3025 sequence microarray for M. edulis, we performed transcriptomic analysis, identifying 57 differentially expressed sequences. Hierarchical clustering of these sequences successfully distinguished the different treatment groups demonstrating that the expression profiles were reproducible among the treatments. Enrichment analysis of gene ontology terms identified several biological processes that were perturbed by the treatments, including nucleoside phosphate biosynthetic processes, mRNA metabolic processes, and response to stress. To identify transcripts whose expression level correlated with metal bioaccumulation, we performed Pearson correlation analysis. Several transcripts correlated with gill metal concentrations including mt10, mt20, and contig 48, an unknown transcript containing a wsc domain. In addition

  2. Modelling of the intragranular back-stress and recovery in FCC single crystals and polycrystals

    Energy Technology Data Exchange (ETDEWEB)

    Sauzay, M

    2003-07-01

    High temperature mechanical tests including recovery times on FCC metals or alloys involve at least two mechanisms. First, the formation of a two phase dislocation microstructure (cells, walls/channels... ) induces intragranular back-stress and hardening. Second, if the recovery time and the temperature are large enough, the previously formed dislocation microstructure can disappear, even if no remote stress is applied. Simple models of these two mechanisms are proposed. They are based on TEM observations and are validated comparing with several measurements from the literature. These models do not use arty fitted parameter and could help to predict the macroscopic behavior during creep-fatigue tests. (author)

  3. Modelling of the intragranular back-stress and recovery in FCC single crystals and polycrystals

    International Nuclear Information System (INIS)

    Sauzay, M.

    2003-01-01

    High temperature mechanical tests including recovery times on FCC metals or alloys involve at least two mechanisms. First, the formation of a two phase dislocation microstructure (cells, walls/channels... ) induces intragranular back-stress and hardening. Second, if the recovery time and the temperature are large enough, the previously formed dislocation microstructure can disappear, even if no remote stress is applied. Simple models of these two mechanisms are proposed. They are based on TEM observations and are validated comparing with several measurements from the literature. These models do not use arty fitted parameter and could help to predict the macroscopic behavior during creep-fatigue tests. (author)

  4. Exploring the use of thermal infrared imaging in human stress research.

    Directory of Open Access Journals (Sweden)

    Veronika Engert

    Full Text Available High resolution thermal infrared imaging is a pioneering method giving indices of sympathetic activity via the contact-free recording of facial tissues (thermal imprints. Compared to established stress markers, the great advantage of this method is its non-invasiveness. The goal of our study was to pilot the use of thermal infrared imaging in the classical setting of human stress research. Thermal imprints were compared to established stress markers (heart rate, heart rate variability, finger temperature, alpha-amylase and cortisol in 15 participants undergoing anticipation, stress and recovery phases of two laboratory stress tests, the Cold Pressor Test and the Trier Social Stress Test. The majority of the thermal imprints proved to be change-sensitive in both tests. While correlations between the thermal imprints and established stress markers were mostly non-significant, the thermal imprints (but not the established stress makers did correlate with stress-induced mood changes. Multivariate pattern analysis revealed that in contrast to the established stress markers the thermal imprints could not disambiguate anticipation, stress and recovery phases of both tests. Overall, these results suggest that thermal infrared imaging is a valuable method for the estimation of sympathetic activity in the stress laboratory setting. The use of this non-invasive method may be particularly beneficial for covert recordings, in the study of special populations showing difficulties in complying with the standard instruments of data collection and in the domain of psychophysiological covariance research. Meanwhile, the established stress markers seem to be superior when it comes to the characterization of complex physiological states during the different phases of the stress cycle.

  5. Relaxation of stresses during reduction of anode supported SOFCs

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Jørgensen, Peter Stanley

    2016-01-01

    To assess the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of a Ni-YSZ anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. Thus, the phenomenon of accelerated creep during reduction has to be considered both in the production of stacks and in the analysis of the stress field...... of reduction should decrease significantly over minutes. In this work these internal stresses are measured in-situ before and after the reduction by use of X-ray diffraction. This is done by determining the elastic micro-strains (correlating to the stresses), which are assessed from the widening of the Bragg...

  6. Learn to manage stress

    Science.gov (United States)

    Stress - managing; Stress - recognizing; Stress - relaxation techniques ... LEARN TO RECOGNIZE STRESS The first step in managing stress is recognizing it in your life. Everyone feels stress in a different way. ...

  7. Estimation of shear stress in counter-current gas-liquid annular two-phase flow

    International Nuclear Information System (INIS)

    Abe, Yutaka; Akimoto, Hajime; Murao, Yoshio

    1991-01-01

    The accuracy of the correlations of the friction factor is important for the counter-current flow (CCF) analysis with two-fluid model. However, existing two fluid model codes use the correlations of friction factors for co-current flow or correlation developed based on the assumption of no wall shear stress. The assessment calculation for two fluid model code with those existing correlations of friction factors shows the falling water flow rate is overestimated. Analytical model is developed to calculate the shear stress distribution in water film at CCF in order to get the information on the shear stress at the interface and the wall. The analytical results with the analysis model and Bharathan's CCF data shows that the wall shear stress acting on the falling water film is almost same order as the interfacial shear stress and the correlations for co-current flow cannot be applied to the counter-current flow. Tentative correlations of the interfacial and the wall friction factors are developed based on the results of the present study. (author)

  8. Evaluation of Stress and a Stress-Reduction Program Among Radiologic Technologists.

    Science.gov (United States)

    Reingold, Lynn

    2015-01-01

    To investigate stress levels and causes of stress among radiologic technologists and determine whether an intervention could reduce stress in a selected radiologic technologist population. Demographic characteristics and data on preintervention stress sources and levels were collected through Internet-based questionnaires. A 6-week, self-administered, mindfulness-based stress-reduction program was conducted as a pilot intervention with 42 radiologic technologists from the Veterans Administration Medical Center. Data also were collected postintervention. Identified sources of stress were compared with findings from previous studies. Some radiologic technologists experienced improvement in their perceptions of stress after the intervention. Sources of stress for radiologic technologists were similar to those shown in earlier research, including inconsistent management, poor management communication, conflicting demands, long work hours, excessive workloads, lack of work breaks, and time pressures. The mindfulness-based stress-reduction program is an example of an inexpensive method that could improve personal well-being, reduce work errors, improve relationships in the workplace, and increase job satisfaction. More research is needed to determine the best type of intervention for stress reduction in a larger radiologic technologist population.

  9. Stress and Mood

    Science.gov (United States)

    ... Relaxation Emotions & Relationships HealthyYouTXT Tools Home » Stress & Mood Stress & Mood Many people who go back to smoking ... story: Time Out Times 10 >> share What Causes Stress? Read full story: What Causes Stress? >> share The ...

  10. Repetitive Stress Injuries

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Repetitive Stress Injuries KidsHealth / For Teens / Repetitive Stress Injuries What's ... t had any problems since. What Are Repetitive Stress Injuries? Repetitive stress injuries (RSIs) are injuries that ...

  11. Identifying the role of different personality traits on the relationship between stress and food choice

    OpenAIRE

    Trew, Marissa

    2014-01-01

    Research shows that high levels of stress correlate with higher consumption of high- fat and high-sugar snack-type foods, particularly amongst women. However, it has been observed that not all individuals are vulnerable to this pattern of ‘stress-related’ eating. Both stress and dietary habits have been strongly correlated with specific personality traits but previous research has neglected to observe whether personality traits significantly affect correlations between perceived stress and ty...

  12. Correlation between bone mineral density and oxidative stress in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Tripti Sharma

    2015-01-01

    Full Text Available Background: Postmenopausal osteoporosis affects large fraction of elderly women. Oxidative stress (OS appears to be involved in its pathogenesis. The scarcity of human studies focusing on the correlation between bone mineral density (BMD and OS in postmenopausal women has prompted us to study on this issue. Materials and Methods: We conducted a cross sectional study in 95 subjects, between 21-65 years of age, including postmenopausal osteoporotic females (n = 35, healthy postmenopausal females (n = 30 and healthy females in reproductive age group (n = 30. We measured serum antioxidant activity of superoxide dismutase (SOD, catalase, glutathione peroxidase (GPx, and total antioxidant power (TAP. BMD was obtained at lumbar spine and femur neck by dual-energy X-ray absorptiometry scan. Osteoporosis was considered when subjects had a BMD of 2.5 standard deviations or more below the mean value for young adults. Results: Serum GPx, SOD, catalase and TAP level were found significantly lower in osteoporotic postmenopausal group as compared to healthy postmenopausal women and women in healthy reproductive age group healthy reproductive women (P 0.005. Conclusion: These findings support that oxidative stress plays an important role in pathogenesis of postmenopausal osteoporosis. We did not find any significant association between BMD and serum level of antioxidants (P > 0.05. The failure to detect this association does not preclude the role of OS in osteoporosis because OS is complex and dynamic process.

  13. Pressure pain sensitivity as a marker for stress and pressure pain sensitivity-guided stress management in women with primary breast cancer.

    Science.gov (United States)

    Axelsson, Christen K; Ballegaard, Søren; Karpatschof, Benny; Schousen, Peer

    2014-08-01

    To validate (1) Pressure Pain Sensitivity (PPS) as a marker for stress and (2) a PPS-guided intervention in women with primary Breast Cancer (BC). (1) A total of 58 women with BC were examined before and after 6 months of intervention. A control group of 165 women office employees was divided in a High Stress Group (HSG, n = 37) and a Low Stress Group (LSG, n = 128) to evaluate the association between PPS, questionnaire-related Quality of Life (QOL) and self-evaluated stress. (2) A PPS-guided stress management program (n = 40) was compared to a Psychosocial Group Intervention (PGI, n = 91) and no treatment (n = 86) with respect to a European Organization for Research and Treatment of Cancer (EORTC) questionnaire measured QOL. (1) Resting PPS and changes in PPS during the intervention period correlated significantly to EORTC and Short Form 36 (SF 36) main scores: (all p stress scores (all p stress. (2) The PPS-guided intervention group improved EORTC main score, pain and nausea, when compared to the control groups (all p stress. PPS-guided intervention improved QOL in women with breast cancer.

  14. prevalence and correlates of job stress among junior doctors

    African Journals Online (AJOL)

    ABSTRACT. Introduction: Doctors respond differently to their complex work environment, ... Conclusion: The prevalence of stress in this study is high, and job dissatisfaction and poor ..... Stansfeld S, Head J, Marmot M. Work related factors and ...

  15. The relationship of work stress and family stress to the self-rated health of women employed in the industrial sector in Korea.

    Science.gov (United States)

    Kim, Gwang Suk; Cho, Won Jung; Lee, Chung Yul; Marion, Lucy N; Kim, Mi Ja

    2005-01-01

    To identify the relationship of work stress and family stress to the health of women in Korea. Cross-sectional study. Three hundred and thirty-one married women working in 14 manufacturing companies in Korea. Subjects responded to a questionnaire that included items on work stress, family stress, social support, and general characteristics. Perceived health status (PHS) was assessed with the Short Form-36. There was a significant positive relationship between social support and PHS, but significant negative relationships were found between PHS and work stress as well as family stress. Hierarchical multiple regression analysis explained the health status of married working women by four categories: personal, work related, family related, and social support, and accounted for 45.4% of the variance. When family-related factors were added to the model, the power of explanation was increased by 17.9% compared with the explained variance. Family stress was a major variable not only for explaining the variance but also for correlating with health status. Both work stress and family stress should be considered together when addressing the health of working women in the industrial sector in Korea.

  16. Various cellular stress components change as the rat ages: An insight into the putative overall age-related cellular stress network.

    Science.gov (United States)

    Cueno, Marni E; Imai, Kenichi

    2018-02-01

    Cellular stress is mainly comprised of oxidative, nitrosative, and endoplasmic reticulum stresses and has long been correlated to the ageing process. Surprisingly, the age-related difference among the various components in each independent stress pathway and the possible significance of these components in relation to the overall cellular stress network remain to be clearly elucidated. In this study, we obtained blood from ageing rats upon reaching 20-, 40-, and 72-wk.-old. Subsequently, we measured representative cellular stress-linked biomolecules (H 2 O 2 , glutathione reductase, heme, NADPH, NADP, nitric oxide, GADD153) and cell signals [substance P (SP), free fatty acid, calcium, NF-κB] in either or both blood serum and cytosol. Subsequently, network analysis of the overall cellular stress network was performed. Our results show that there are changes affecting stress-linked biomolecules and cell signals as the rat ages. Additionally, based on our network analysis data, we postulate that NADPH, H 2 O 2 , GADD153, and SP are the key components and the interactions between these components are central to the overall age-related cellular stress network in the rat blood. Thus, we propose that the main pathway affecting the overall age-related cellular stress network in the rat blood would entail NADPH-related oxidative stress (involving H 2 O 2 ) triggering GADD153 activation leading to SP induction which in-turn affects other cell signals. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Traditional Machismo and Caballerismo as Correlates of Posttraumatic Stress Disorder, Psychological Distress, and Relationship Satisfaction in Hispanic Veterans

    Science.gov (United States)

    Herrera, Catherine J.; Owens, Gina P.; Mallinckrodt, Brent

    2013-01-01

    An online survey was used to examine 45 Hispanic male veterans' traditional machismo and caballerismo as correlates of posttraumatic stress disorder (PTSD), psychological distress, and relationship satisfaction. Higher traditional machismo was associated with higher PTSD severity and distress and lower relationship satisfaction. Psychometric…

  18. Sustainability of compressive residual stress by stress improvement processes

    International Nuclear Information System (INIS)

    Nishikawa, Satoru; Okita, Shigeru; Yamaguchi, Atsunori

    2013-01-01

    Stress improvement processes are countermeasures against stress corrosion cracking in nuclear power plant components. It is necessary to confirm whether compressive residual stress induced by stress improvement processes can be sustained under operation environment. In order to evaluate stability of the compressive residual stress in 60-year operating conditions, the 0.07% cyclic strains of 200 times at 593 K were applied to the welded specimens, then a thermal aging treatment for 1.66x10 6 s at 673 K was carried out. As the result, it was confirmed that the compressive residual stresses were sustained on both surfaces of the dissimilar welds of austenitic stainless steel (SUS316L) and nickel base alloy (NCF600 and alloy 182) processed by laser peening (LP), water jet peening (WJP), ultrasonic shot peening (USP), shot peening (SP) and polishing under 60-year operating conditions. (author)

  19. Life stress and mental disorders in the South African Stress and ...

    African Journals Online (AJOL)

    Life stress and mental disorders in the South African Stress and Health study. ... Although stressful life events (SLEs) are associated with psychopathology, the ... life stress and sociodemographic predictors of 12-month and lifetime disorder.

  20. Examining the stress-burnout relationship: the mediating role of negative thoughts.

    Science.gov (United States)

    Chang, Ko-Hsin; Lu, Frank J H; Chyi, Theresa; Hsu, Ya-Wen; Chan, Shi-Wei; Wang, Erica T W

    2017-01-01

    Using Smith's (1986) cognitive-affective model of athletic burnout as a guiding framework, the purpose of this study was to examine the relationships among athletes' stress in life, negative thoughts, and the mediating role of negative thoughts on the stress-burnout relationship. A total of 300 college student-athletes (males = 174; females = 126, M age  = 20.43 y, SD = 1.68) completed the College Student Athlete's Life Stress Scale (CSALSS; Lu et al., 2012), the Automatic Thoughts Questionnaire (ATQ; Hollon & Kendall, 1980), and the Athlete Burnout Questionnaire (ABQ; Raedeke & Smith, 2001). Correlational analyses found that two types of life stress and four types of negative thoughts correlated with burnout. Additionally, hierarchical regression analyses found that four types of negative thoughts partially mediated the stress-burnout relationship. We concluded that an athlete's negative thoughts play a pivotal role in predicting athletes' stress-burnout relationship. Future study may examine how irrational cognition influences athletes' motivation and psychological well-being.

  1. Examining the stress-burnout relationship: the mediating role of negative thoughts

    Science.gov (United States)

    Chyi, Theresa; Hsu, Ya-Wen; Chan, Shi-Wei; Wang, Erica T.W.

    2017-01-01

    Background Using Smith’s (1986) cognitive-affective model of athletic burnout as a guiding framework, the purpose of this study was to examine the relationships among athletes’ stress in life, negative thoughts, and the mediating role of negative thoughts on the stress-burnout relationship. Methods A total of 300 college student-athletes (males = 174; females = 126, Mage = 20.43 y, SD = 1.68) completed the College Student Athlete’s Life Stress Scale (CSALSS; Lu et al., 2012), the Automatic Thoughts Questionnaire (ATQ; Hollon & Kendall, 1980), and the Athlete Burnout Questionnaire (ABQ; Raedeke & Smith, 2001). Results Correlational analyses found that two types of life stress and four types of negative thoughts correlated with burnout. Additionally, hierarchical regression analyses found that four types of negative thoughts partially mediated the stress-burnout relationship. Discussion We concluded that an athlete’s negative thoughts play a pivotal role in predicting athletes’ stress-burnout relationship. Future study may examine how irrational cognition influences athletes’ motivation and psychological well-being. PMID:29302397

  2. Finite element modelling of stress development during deposition of ion assisted coatings

    International Nuclear Information System (INIS)

    Ward, D.J.; Arnell, R.D.

    2002-01-01

    Ion assisted physical vapour deposited (IAPVD) films typically have a high state of residual stress. This residual stress comprises two components: a thermal stress, which forms as the system cools to room temperature; and an intrinsic stress which is caused by the processes of deposition. Much work has been published on the tribology and mechanical behaviour of surface coatings without consideration of the residual stress. It was therefore considered desirable to develop a finite element (FE) simulation to be used either as a precursor to any realistic mechanical study of the behaviour of such surface coatings, or to be used as a tool to study the effects of varying the deposition parameters. Previous experimental work has shown that the residual stress is related to deposition parameters, such as incident ion and atom fluxes and energies, and recent molecular dynamics studies have indicated that trapped inert gas species may play a major role in the mechanism for creation of the intrinsic stress. The FE simulation assumes that the processes of ion bombardment and material deposition are consecutive, but as the analysis time step tends to zero this assumption approximates the simultaneity of the processes. Suitable mathematical descriptions are employed in the bombarded region of the growing coating to simulate the macroscopic effects of the microscopic atomic collision phenomena and diffusion processes. Two finite element simulations are presented. The first is based on an analytical model, which has gained popular acceptance and this was presented in a previous year at this conference. The second builds on this to simulate wider aspects of known behaviour and is presented in this follow-up paper. The predicted trends of mean stress and its distribution are similar to those observed in published experimental work

  3. Thermal stress-dependent dilation of concrete

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.; Marchertas, A.H.

    1984-01-01

    Recent studies in nuclear fast reactor safety consider the possibility of concrete containment being subjected to extremely severe environmental conditions. Certain safety scenarios subject the concrete to very high temperatures hence raising the concern of containment integrity. Some of the main detrimental effects of high temperature on concrete are: reduction of strength, redistribution of moisture and etc. Consequently, analytical prediction of concrete response under the high temperature conditions becomes very complex. A rather simple but important experiment of concrete at high temperatures was conducted by Anderberg and Thelandersson. The test samples were small so that moisture was free to evaporate with no appreciable gradient as the temperature increased. Their results revealed that good correlation with analysis could be obtained if thermal expansion was made a function of both temperature and stress. The method of relating the thermal strain to temperature and stress has been integrated into the TEMP-STRESS code. Thus, high temperature concrete computational capability is now available for thermal-stress calculations

  4. To stress or not to stress: a question of models.

    Science.gov (United States)

    Gray, J Megan; Chaouloff, Francis; Hill, Matthew N

    2015-01-05

    Stress research is a rapidly evolving field that encompasses numerous disciplines ranging from neuroscience to metabolism. With many new researchers migrating into the field, navigating the hows and whys of specific research questions can sometimes be enigmatic given the availability of so many models in the stress field. Additionally, as with every field, there are many seemingly minor experimental details that can have dramatic influences on data interpretation, although many of these are unknown to those not familiar with the field. The aim of this overview is to provide some suggestions and points to guide researchers moving into the stress field and highlight relevant methodological points that they should consider when choosing a model for stress and deciding how to structure a study. We briefly provide a primer on the basics of endpoint measurements in the stress field, factors to consider when choosing a model for acute stress, the difference between repeated and chronic stress, and importantly, influencing variables that modulate endpoints of analysis in stress work. Copyright © 2015 John Wiley & Sons, Inc.

  5. Neutron diffraction investigation of hysteresis reduction and increase in linearity in the stress-strain response of superelastic NiTi

    International Nuclear Information System (INIS)

    Rathod, C.R.; Clausen, B.; Bourke, M.A.M.; Vaidyanathan, R.

    2006-01-01

    In situ neutron diffraction measurements during loading have been performed on plastically deformed superelastic NiTi samples. The measurements observed retained B19 ' phase in the unloaded state as a result of the plastic deformation in otherwise completely B2 phase samples. A reversible stress-induced B2-B19 ' transformation on application and removal of stress occurred in the presence of this retained B19 ' phase. The amount and orientation of this retained B19 ' phase changed with cycling. Such direct atomic scale observations in the bulk are used here for the first time to qualitatively elucidate the macroscopic stress-strain response in plastically deformed superelastic NiTi

  6. Stress og insomni

    DEFF Research Database (Denmark)

    Jennum, Poul; Zachariae, Bobby

    2012-01-01

    Insomnia and stress are two conditions, which are strongly associated and appear to be pathophysiologically integrated: the occurrence of stress increases the risk of insomnia, insomnia exacerbates stress, and coexistence of both factors has a negative influence on their prognosis. Stress...

  7. The relative impact of work-related stress, life stress and driving environment stress on driving outcomes.

    Science.gov (United States)

    Rowden, Peter; Matthews, Gerald; Watson, Barry; Biggs, Herbert

    2011-07-01

    Previous research has shown the association between stress and crash involvement. The impact of stress on road safety may also be mediated by behaviours including cognitive lapses, errors, and intentional traffic violations. This study aimed to provide a further understanding of the impact that stress from different sources may have upon driving behaviour and road safety. It is asserted that both stress extraneous to the driving environment and stress directly elicited by driving must be considered part of a dynamic system that may have a negative impact on driving behaviours. Two hundred and forty-seven public sector employees from Queensland, Australia, completed self-report measures examining demographics, subjective work-related stress, daily hassles, and aspects of general mental health. Additionally, the Driver Behaviour Questionnaire (DBQ) and the Driver Stress Inventory (DSI) were administered. All participants drove for work purposes regularly, however the study did not specifically focus on full-time professional drivers. Confirmatory factor analysis of the predictor variables revealed three factors: DSI negative affect; DSI risk taking; and extraneous influences (daily hassles, work-related stress, and general mental health). Moderate intercorrelations were found between each of these factors confirming the 'spillover' effect. That is, driver stress is reciprocally related to stress in other domains including work and domestic life. Structural equation modelling (SEM) showed that the DSI negative affect factor influenced both lapses and errors, whereas the DSI risk-taking factor was the strongest influence on violations. The SEMs also confirmed that daily hassles extraneous to the driving environment may influence DBQ lapses and violations independently. Accordingly, interventions may be developed to increase driver awareness of the dangers of excessive emotional responses to both driving events and daily hassles (e.g. driving fast to 'blow off steam

  8. Work Stress

    OpenAIRE

    Roeters, Anne

    2014-01-01

    Most of us agree that stress is a growing problem within organizations. We hear about the postal workers who had killed fellow employees and supervisors, and then hear that a major cause of tension is at work. Friends tell us that they are stressed due to increased workload and he has to work overtime because the company is restructured. We read the polls that employees complain about the stress in trying to balance family life with the work. Stress is a dynamic condition in which an individu...

  9. Perceived Stress Scale: reliability and validity study in Greece.

    Science.gov (United States)

    Andreou, Eleni; Alexopoulos, Evangelos C; Lionis, Christos; Varvogli, Liza; Gnardellis, Charalambos; Chrousos, George P; Darviri, Christina

    2011-08-01

    To translate the Perceived Stress Scale (versions PSS-4, -10 and -14) and to assess its psychometric properties in a sample of general Greek population. 941 individuals completed anonymously questionnaires comprising of PSS, the Depression Anxiety and Stress scale (DASS-21 version), and a list of stress-related symptoms. Psychometric properties of PSS were investigated by confirmatory factor analysis (construct validity), Cronbach's alpha (reliability), and by investigating relations with the DASS-21 scores and the number of symptoms, across individuals' characteristics. The two-factor structure of PSS-10 and PSS-14 was confirmed in our analysis. We found satisfactory Cronbach's alpha values (0.82 for the full scale) for PSS-14 and PSS-10 and marginal satisfactory values for PSS-4 (0.69). PSS score exhibited high correlation coefficients with DASS-21 subscales scores, meaning stress (r = 0.64), depression (r = 0.61), and anxiety (r = 0.54). Women reported significantly more stress compared to men and divorced or widows compared to married or singled only. A strong significant (p < 0.001) positive correlation between the stress score and the number of self-reported symptoms was also noted. The Greek versions of the PSS-14 and PSS-10 exhibited satisfactory psychometric properties and their use for research and health care practice is warranted.

  10. Sex-specific hippocampal 5-hydroxymethylcytosine is disrupted in response to acute stress.

    Science.gov (United States)

    Papale, Ligia A; Li, Sisi; Madrid, Andy; Zhang, Qi; Chen, Li; Chopra, Pankaj; Jin, Peng; Keleş, Sündüz; Alisch, Reid S

    2016-12-01

    Environmental stress is among the most important contributors to increased susceptibility to develop psychiatric disorders. While it is well known that acute environmental stress alters gene expression, the molecular mechanisms underlying these changes remain largely unknown. 5-hydroxymethylcytosine (5hmC) is a novel environmentally sensitive epigenetic modification that is highly enriched in neurons and is associated with active neuronal transcription. Recently, we reported a genome-wide disruption of hippocampal 5hmC in male mice following acute stress that was correlated to altered transcript levels of genes in known stress related pathways. Since sex-specific endocrine mechanisms respond to environmental stimulus by altering the neuronal epigenome, we examined the genome-wide profile of hippocampal 5hmC in female mice following exposure to acute stress and identified 363 differentially hydroxymethylated regions (DhMRs) linked to known (e.g., Nr3c1 and Ntrk2) and potentially novel genes associated with stress response and psychiatric disorders. Integration of hippocampal expression data from the same female mice found stress-related hydroxymethylation correlated to altered transcript levels. Finally, characterization of stress-induced sex-specific 5hmC profiles in the hippocampus revealed 778 sex-specific acute stress-induced DhMRs some of which were correlated to altered transcript levels that produce sex-specific isoforms in response to stress. Together, the alterations in 5hmC presented here provide a possible molecular mechanism for the adaptive sex-specific response to stress that may augment the design of novel therapeutic agents that will have optimal effectiveness in each sex. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Stress

    Science.gov (United States)

    ... taking care of an aging parent. With mental stress, the body pumps out hormones to no avail. Neither fighting ... with type 1 diabetes. This difference makes sense. Stress blocks the body from releasing insulin in people with type 2 ...

  12. [Association between occupational stress and aminotransferase activity in patients with metabolic syndrome].

    Science.gov (United States)

    Zhao, H; Song, L; Qiang, Y; Liu, H R; Qiu, F Y; Li, X Z; Song, H

    2016-12-20

    Objective: To investigate the association between occupational stress and activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in patients with metabolic syndrome. Methods: A case-control study was performed. According to inclusion and exclusion criteria, among the staff members of enterprises and public institutions aged 20~60 years who underwent physical examination in The Affiliated Hospital of Ningxia Medical University and The People's Hospital of Wuzhong from October 2011 to October 2012, 622 patients with metabolic syndrome who did not have a blood relationship with each other were enrolled as case group, and 600 healthy staff members who also did not have a blood relationshipwith each otherwere enrolled as control group. Questionnaire investigation, chronic occupational stress investigation, physical examination, and laboratory tests were performed for all subjects. Results: Compared with the control group, the case group had significantly higher serum levels and abnormal rates of AST and ALT ( t =-4.338 and-5.485, χ(2)=11.168 and 34.302, all P occupational stresses in both groups ( F =2.192 and 2.567, χ(2)=2.694 and 5.402, all P >0.05) , but there were significant differencesbetween the subgroups in all subjects ( F =5.005, χ(2)=6.398, all P occupational stresses in the case group, the control group, and all subjects ( F =0.845, 0.450, and 1.416, χ(2)=2.564, 1.344, and 3.147, all P >0.05) . The partial correlation analysis showed that the total score of occupational stress was positively correlated withthe serum level of AST ( r =0.071, P 0.05) , and that the serum level of AST was positively correlated with that of ALT ( r =0.736, P occupational stress was positively correlated with the serum level of AST ( r =0.069, P 0.05) , and the serum level of AST was positively correlated with that of ALT ( r =0.730, P occupational stress ( b =0.131, P =0.013) . Conclusion: Occupational stress is associated with increased serum level

  13. Chronic Stress Impairs Prefrontal Cortex-Dependent Response Inhibition and Spatial Working Memory

    Science.gov (United States)

    Mika, Agnieszka; Mazur, Gabriel J.; Hoffman, Ann N.; Talboom, Joshua S.; Bimonte-Nelson, Heather A.; Sanabria, Federico; Conrad, Cheryl D.

    2012-01-01

    Chronic stress leads to neurochemical and structural alterations in the prefrontal cortex (PFC) that correspond to deficits in PFC-mediated behaviors. The present study examined the effects of chronic restraint stress on response inhibition (using a response-withholding task, fixed-minimum interval schedule of reinforcement, or FMI), and working memory (using a radial arm water maze, RAWM). Adult male Sprague Dawley rats were first trained on the RAWM and subsequently trained on FMI. Following acquisition of FMI, rats were assigned to a restraint stress (6h/d/28d in wire mesh restrainers) or control condition. Immediately after chronic stress, rats were tested on FMI and subsequently on RAWM. FMI results suggest that chronic stress reduces response inhibition capacity and motivation to initiate the task on selective conditions when food reward was not obtained on the preceding trial. RAWM results suggest that chronic stress produces transient deficits in working memory without altering previously consolidated reference memory. Behavioral measures from FMI failed to correlate with metrics from RAWM except for one in which changes in FMI timing precision negatively correlated with changes in RAWM working memory errors for the controls, a finding that was not observed following chronic stress. Fisher’s r to z transformation revealed no significant differences between control and stress with correlation coefficients. These findings are the first to show that chronic stress impairs both response inhibition and working memory, two behaviors that have never been direct compared within the same animals following chronic stress, using FMI, an appetitive task, and RAWM, a non-appetitive task. PMID:22905921

  14. Stress revisited: A critical evaluation of the stress concept

    NARCIS (Netherlands)

    Koolhaas, J.M.; Bartolomucci, A.; Buwalda, B.; de Boer, S.F.; Flügge, G.; Korte, S.M.; Meerloo, P.; Murison, R.; Olivier, B.; Palanza, P.; Richter-Levin, G.; Sgoifo, A.; Steimer, T.; Stiedl, O.; van Dijk, G.; Wöhr, M.; Fuchs, E.

    2011-01-01

    With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely

  15. Stress revisited : a critical evaluation of the stress concept

    NARCIS (Netherlands)

    Koolhaas, J.M.; Bartolomucci, A; Buwalda, B; Flügge, G; de Boer, Sietse; Korte, S M; Meerlo, P; Murison, R; Olivier, B; Palanza, P; Richter-Levin, G; Sgoifo, A; Steimer, T; Stiedl, O; van Dijk, G; Wöhr, M; Fuchs, E

    2011-01-01

    With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely

  16. Relationship between job stress, temperament and depressive symptoms in female nurses

    Directory of Open Access Journals (Sweden)

    Yoko Kikuchi

    2014-08-01

    Full Text Available Objectives: A casual relationship between temperament, job stress and depressive symptoms has not been established yet. The purpose of this study was to assess the relationships between job stress, temperament and depressive symptoms in female nurses at a Japanese general hospital. Material and Methods: A self-report survey was conducted among 706 nurses. We measured job stress, temperament, and depressive symptoms using the Brief-Job Stress Questionnaire, the TEMPS-A and a screening scale of items from the Ministry of Health, Labour and Welfare of Japan. In order to examine the causal relationship between the measures the stepwise multiple regression and path analyses were used. Results: Depressive symptoms were modestly correlated with job stress (γ = -0.23-0.30. Except for hyperthymic temperament measures, the correlations between depressive symptoms and temperament types were significant and moderate (γ = 0.36-0.50. Overtime, job control as well as depressive and cyclothymic types of temperament were significantly correlated with depressive symptoms (β = 0.15, p < 0.05; β = 0.19, p < 0.01; β = 0.26, p < 0.001; β = 0.32, p < 0.001, respectively. Path-analysis revealed that depressive and cyclothymic types of temperament influenced depressive symptoms both directly (β = 0.67, p < 0.001 and indirectly via job stress (β = 0.35, p < 0.001 from temperament to job stress; β = 0.20, p < 0.05 from job stress to depressive symptoms. Irritable and anxious types of temperament and quantitative job overload did not contri­bute to the path-analytic model. Conclusions: Health care professionals should consider temperament, especially depressive and cyclothymic types, in order to help employees cope better with job stress factors. We need further research about the effective intervention to help employees better cope with their job stress.

  17. Minority Stress and Stress Proliferation Among Same-Sex and Other Marginalized Couples.

    Science.gov (United States)

    LeBlanc, Allen J; Frost, David M; Wight, Richard G

    2015-02-01

    Drawing from 2 largely isolated approaches to the study of social stress-stress proliferation and minority stress-the authors theorize about stress and mental health among same-sex couples. With this integrated stress framework, they hypothesized that couple-level minority stressors may be experienced by individual partners and jointly by couples as a result of the stigmatized status of their same-sex relationship-a novel concept. They also consider dyadic minority stress processes, which result from the relational experience of individual-level minority stressors between partners. Because this framework includes stressors emanating from both status- (e.g., sexual minority) and role-based (e.g., partner) stress domains, it facilitates the study of stress proliferation linking minority stress (e.g., discrimination), more commonly experienced relational stress (e.g., conflict), and mental health. This framework can be applied to the study of stress and health among other marginalized couples, such as interracial/ethnic, interfaith, and age-discrepant couples.

  18. Coping with stress and quality of life in women with stress urinary incontinence

    Directory of Open Access Journals (Sweden)

    Jolanta Adamczuk

    2015-09-01

    Full Text Available Introduction: Urinary incontinence (UI involves uncontrolled leakage of urine through the urethra as a result of damage to its sphincter muscle and a disturbed function of the urogenital diaphragm within the pelvis minor. The symptoms of UI radically impair psychological, somatic, and social functioning. The aim of each disease stress coping process is to reduce the impact of harmful agents as well as the acquisition of necessary preventive measures in order to combat the disorder. Aim of the study was to assess the relationship between coping styles used when dealing with stress associated with disease and the quality of life. Material and methods: The study was carried out at an outpatients’ clinic located in the Lublin Province (eastern Poland, covering 150 women with diagnosed stress urinary incontinence, aged between 32 and 79. The following methods were used: (a Coping Inventory for Stressful Situations (Endler, Parker to assess coping styles, (b CASP-19 scale (Higgins, Hyde, Wiggins, Blade to measure the overall quality of life, and (c Urinary Incontinence Life Quality Scale (Szymona-Pałkowska, Kraczkowski. Results : The preferred style in the studied group of women was Task-Oriented Coping. This style is associated with a low score on the Independence from Symptoms scale and low Control, being simultaneously correlated with Autonomy and Self-Realisation. Emotion-Oriented Coping is associated with low psychological, physical and social well-being, as well as with little independence from the disease symptoms, little pleasure and self-realisation, but it gives a sense of internal control. Avoidance-Oriented Coping does not significantly correlate with any of the Overall Quality of Life dimensions. Conclusions : Women suffering from UI tend to try to solve their problem by means of cognitive transformation. In their situation, clinging to the problem turns out to be a depressing factor and entails a lower quality of their life.

  19. Neuromuscular Stress.

    Science.gov (United States)

    White, Timothy P.; Kern, Marialice

    1994-01-01

    Discusses exercise-induced stress that results from motor unit recruitment, the impact of recruitment on selected systemic support systems, and some of the environmental overlays that affect the degree of physiological stress. Adaptations to sustained changes in physical activity and muscle and myotendinous injury induced by stress are examined.…

  20. Stress strain tensors with their application to x-ray stress measurement

    International Nuclear Information System (INIS)

    Kurita, Masanori

    2015-01-01

    This paper describes in detail the method of obtaining the formulas of stress-strain tensor that express the directional dependence of stress-strain, that is, how these values change in response to coordinate transformation, and clarifies the preconditions for supporting both formulas. The two conversion formulas are both the second order of tensor, and the formula of strain tensor not only does not use the relational expression of stress and strain at all, but also is obtained completely independently of the formula of stress tensor. Except for the condition that the strain is very small (elastic deformation) in the conversion formula of strain, both formulas unconditionally come into effect. In other words, both formulas hold true even in the isotropic elastic body or anisotropic elastic body. It was shown that the conversion formula of strain can be derived from the conversion formula of stress using the formula of Hooke for isotropic elastic body. From these three-dimensional expressions, the two-dimensional stress-strain coordinate conversion formula that is used for Mohr's stress-strain circle was derived. It was shown that these formulas hold true for three-dimensional stress condition with stress-strain components in the three-axial direction that are not plane stress nor plane strain condition. In addition, as an application case of this theory, two-dimensional and three-dimensional X-ray stress measurements that are effective for residual stress measurement were shown. (A.O.)

  1. Development of Kossel micro-diffraction for strain and stress analysis at the micrometer scale: applications to crystalline materials

    International Nuclear Information System (INIS)

    Bouscaud, D.

    2012-01-01

    X-ray diffraction is a non-destructive method frequently used in materials science to analyse the stress state at a macroscopic scale. Due to the growing complexity of new materials and their applications, it is necessary to know the strain and stress state at a lower scale. Thus, a Kossel micro-diffraction experimental set-up was developed inside a scanning electron microscope. It allows to obtain the crystallographic orientation as well as the strains and stresses within a volume of a few cubic micrometers. Some experiments were also performed using a synchrotron radiation. An experimental procedure was developed to optimize the acquisition of Kossel line patterns and their post-processing. The stress calculation from Kossel patterns was validated by comparing the stress state of single crystals during in situ mechanical loading, obtained by Kossel micro-diffraction and with classical diffraction methods. Then Kossel micro-diffraction was applied to polycrystalline samples by gradually decreasing the grain size. Intergranular stress heterogeneities were for example measured in an interstitial-free steel. Experiments were finally carried out in thin layer samples representative of microelectronic components. (author)

  2. Rock stress investigations

    International Nuclear Information System (INIS)

    Pahl, A.; Heusermann, St.; Braeuer, V.; Gloeggler, W.

    1989-04-01

    On the research project 'Rock Stress Mesurements' the BGR has developed and tested several methods for use in boreholes at a depth of 200 m. Indirect stress measurements using overcoring methods with BGR-probes and CSIR-triaxial cells as well as direct stress measurements using the hydraulic-fracturing method were made. To determine in-situ rock deformation behavior borehole deformation tests, using a BGR-dilatometer, were performed. Two types of the BGR-probe were applied: a four-component-probe to determine horizontal stresses and a five-component-probe to determine a quasi three-dimensional stress field. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on low cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (author) 4 tabs., 76 figs., 31 refs

  3. Pad stress tests with increasing load for the diagnosis of stress urinary incontinence.

    Science.gov (United States)

    Rimstad, Liv; Larsen, Elsa Skjønhaug; Schiøtz, Hjalmar A; Kulseng-Hanssen, Sigurd

    2014-09-01

    The aim of the study was to test the ability of pad stress tests with increasing load (supine, jumping on the floor, and jumping on a trampoline) to document stress incontinence in subjectively stress incontinent women. In this prospective study 147 subjectively stress and mixed incontinent women performed consecutively the three pad stress tests with a bladder volume of 300 ml. Nineteen women performed a second trampoline pad stress test to test repeatability of the test. Nine continent women performed a trampoline pad stress test in order to determine if subjectively continent women would leak during the test. Seventy-two women (49%) leaked during the supine, 136 (93%) leaked during the jumping, and 146 (99%) leaked during the trampoline pad stress test. The differences between pad stress tests were significant with P trampoline pad stress tests was high at 0.8. None of the nine continent women leaked during the trampoline pad stress test. The supine pad stress test has low sensitivity and is therefore often falsely negative. The jumping pad stress test is a simple test to perform and is satisfactory for everyday use. Subjectively stress incontinent women who do not leak during the jumping pad stress test may perform a trampoline pad stress test to document stress incontinence. The trampoline pad stress test is also simple to perform and detected leakage in 91% of the women who did not leak during the jumping pad stress test. © 2013 Wiley Periodicals, Inc.

  4. Neural Correlates of Psychotherapeutic Treatment of Post-traumatic Stress Disorder: A Systematic Literature Review.

    Science.gov (United States)

    Malejko, Kathrin; Abler, Birgit; Plener, Paul L; Straub, Joana

    2017-01-01

    Post-traumatic stress disorder (PTSD) is a common psychiatric disease with changes in neural circuitries. Neurobiological models conceptualize the symptoms of PTSD as correlates of a dysfunctional stress reaction to traumatic events. Functional imaging studies showed an increased amygdala and a decreased prefrontal cortex response in PTSD patients. As psychotherapeutic approaches represent the gold standard for PTSD treatment, it is important to examine its underlying neurobiological correlates. Studies published until August 2016 were selected through systematic literature research in the databases PubMed, PsychInfo, and Cochrane Library's Central Register of Controlled Trials or were identified manually by searching reference lists of selected articles. Search terms were "neural correlates" OR "fMRI" OR "SPECT," AND "therapy" AND "PTSD." A total of 19 articles were included in the present review whereof 15 studies compared pre-to-post-therapy signal changes, six studies related pre-treatment activity to pre-to-post-symptom improvement, and four studies compared neural correlates of responders versus non-responders. The disposed therapy forms were cognitive behavioral therapy (CBT), eye movement desensitization and reprocessing, cognitive therapy, exposure therapy, mindfulness-based intervention, brief eclectic psychotherapy, and unspecified therapy. Successful psychotherapy of PTSD was repeatedly shown to be accompanied by decreased activity in the amygdala and the insula as well as increased activity in the dorsal anterior cingulate cortex (dACC) and hippocampus. Elevated dACC activity prior to treatment was related to subsequent treatment success and a positive predictor for treatment response. Elevated amygdala and insula pre-treatment activities were related to treatment failure. Decreased activity in limbic brain regions and increased activity in frontal brain areas in PTSD patients after successful psychotherapeutic treatment might reflect regained top

  5. The association between stressful life events and depressive symptoms among Cypriot university students: a cross-sectional descriptive correlational study.

    Science.gov (United States)

    Sokratous, Sokratis; Merkouris, Anastasios; Middleton, Nicos; Karanikola, Maria

    2013-12-05

    Previous findings suggest that stressful life events have a causal relationship with depressive symptoms. However, to date little is known concerning the contribution of the number and severity of recent stressful life events on the prevalence of depressive symptoms among university students. The aim of this study was to investigate the prevalence of depressive symptoms and its association with the number and the severity of self-reported stressful life events among university students in Cyprus. A descriptive correlational design with cross sectional comparison was used. The CES-D scale was applied for the assessment of depressive symptoms and the LESS instrument for stressful life events. Both scales were completed anonymously and voluntarily by 1.500 students (response rate 85%). The prevalence of mild to moderate depressive symptoms [CES-D score between 16 and 21] and of clinically significant depressive symptoms [CES-D score ≥ 22] were 18.8% and 25.3% respectively. There were statistically significant differences in clinically significant depressive symptoms by gender, with higher rates among women (x(2) = 8.53, df = 1, p = 0.003). Higher scores on the LESS scale were associated with more frequent reports of clinical depressive symptoms (x(2) = 70.63, df = 4, p life events and clinical depressive symptoms (x(2) = 40.06, df = 4, p stressful life events during the previous year (OR = 2.64 95% CI: 1.02, 6.83) and a severe degree of stress due to these events (total LESS score > 351, OR = 3.03 95% CI: 1.66, 5.39) were more likely to manifest clinical depressive symptoms. The high frequency of occurrence of depressive symptoms among Cypriot university students, as well as the strong association with stressful life events, highlights the need for psychological empowerment strategies towards students by institutional counseling services.

  6. Experiences of chronic stress and mental health concerns among urban Indigenous women.

    Science.gov (United States)

    Benoit, Anita C; Cotnam, Jasmine; Raboud, Janet; Greene, Saara; Beaver, Kerrigan; Zoccole, Art; O'Brien-Teengs, Doe; Balfour, Louise; Wu, Wei; Loutfy, Mona

    2016-10-01

    We measured stress, depression and post-traumatic stress disorder (PTSD) levels of urban Indigenous women living with and without HIV in Ontario, Canada, and identified correlates of depression. We recruited 30 Indigenous women living with HIV and 60 without HIV aged 18 years or older who completed socio-demographic and health questionnaires and validated scales assessing stress, depression and PTSD. Descriptive statistics were conducted to summarize variables and linear regression to identify correlates of depression. 85.6 % of Indigenous women self-identified as First Nation. Co-morbidities other than HIV were self-reported by 82.2 % (n = 74) of the sample. High levels of perceived stress were reported by 57.8 % (n = 52) of the sample and 84.2 % (n = 75) had moderate to high levels of urban stress. High median levels of race-related (51/88, IQR 42-68.5) and parental-related stress (40.5/90, IQR 35-49) scores were reported. 82.2 % (n = 74) reported severe depressive symptoms and 83.2 % (n = 74) severe PTSD. High levels of perceived stress was correlated with high depressive symptoms (estimate 1.28 (95 % CI 0.97-1.58), p stress and physical and mental health concerns. Interventions cutting across diverse health care settings are required for improving and preventing adverse health outcomes.

  7. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors.

    Science.gov (United States)

    Krishnamurthy, Sriram; Badcock, Rodney A; Machavaram, Venkata R; Fernando, Gerard F

    2016-05-28

    Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from -600 µε (conventional processing without pre-stress) to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to "neutralising" the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E-glass composites.

  8. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Sriram Krishnamurthy

    2016-05-01

    Full Text Available Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E

  9. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    Science.gov (United States)

    Krishnamurthy, Sriram; Badcock, Rodney A.; Machavaram, Venkata R.; Fernando, Gerard F.

    2016-01-01

    Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress) to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E-glass composites. PMID

  10. Resistance to oxidative stress induced by paraquat correlates well with both decreased and increased lifespan in Drosophila melanogaster

    NARCIS (Netherlands)

    Vermeulen, CJ; Van De Zande, L; Bijlsma, R

    2005-01-01

    There is increasing support for the notion that genetic variation for lifespan, both within and between species, is correlated with variation in the efficiency of the free radical scavenging system and the ability to withstand oxidative stress. In Drosophila, resistance to dietary paraquat, a free

  11. Anticipatory stress influences decision making under explicit risk conditions.

    Science.gov (United States)

    Starcke, Katrin; Wolf, Oliver T; Markowitsch, Hans J; Brand, Matthias

    2008-12-01

    Recent research has suggested that stress may affect memory, executive functioning, and decision making on the basis of emotional feedback processing. The current study examined whether anticipatory stress affects decision making measured with the Game of Dice Task (GDT), a decision-making task with explicit and stable rules that taps both executive functioning and feedback learning. The authors induced stress in 20 participants by having them anticipate giving a public speech and also examined 20 comparison subjects. The authors assessed the level of stress with questionnaires and endocrine markers (salivary cortisol and alpha-amylase), both revealing that speech anticipation led to increased stress. Results of the GDT showed that participants under stress scored significantly lower than the comparison group and that GDT performance was negatively correlated with the increase of cortisol. Our results indicate that stress can lead to disadvantageous decision making even when explicit and stable information about outcome contingencies is provided.

  12. Stress evaluation of chemical vapor deposited silicon dioxide films

    International Nuclear Information System (INIS)

    Maeda, Masahiko; Itsumi, Manabu

    2002-01-01

    Film stress of chemical vapor deposited silicon dioxide films was evaluated. All of the deposited films show tensile intrinsic stresses. Oxygen partial pressure dependence of the intrinsic stress is very close to that of deposition rate. The intrinsic stress increases with increasing the deposition rate under the same deposition temperature, and decreases with increasing substrate temperature. Electron spin resonance (ESR) active defects in the films were observed when the films were deposited at 380 deg. C and 450 deg. C. The ESR signal intensity decreases drastically with increasing deposition temperature. The intrinsic stress correlates very closely to the intensity of the ESR-active defects, that is, the films with larger intrinsic stress have larger ESR-active defects. It is considered that the intrinsic stress was generated because the voids caused by local bond disorder were formed during random network formation among the SiO 4 tetrahedra. This local bond disorder also causes the ESR-active defects

  13. Interoception and Stress

    Directory of Open Access Journals (Sweden)

    André eSchulz

    2015-07-01

    Full Text Available Afferent neural signals are continuously transmitted from visceral organs to the brain. Interoception refers to the processing of visceral-afferent neural signals by the central nervous system, which can finally result in the conscious perception of bodily processes. Interoception can, therefore, be described as a prominent example of information processing on the ascending branch of the brain-body axis. Stress responses involve a complex neuro-behavioral cascade, which is elicited when the organism is confronted with a potentially harmful stimulus. As this stress cascade comprises a range of neural and endocrine pathways, stress can be conceptualized as a communication process on the descending branch of the brain-body axis. Interoception and stress are, therefore, associated via the bi-directional transmission of information on the brain-body axis. It could be argued that excessive and/or enduring activation (e.g. by acute or chronic stress of neural circuits, which are responsible for successful communication on the brain-body axis, induces malfunction and dysregulation of these information processes. As a consequence, interoceptive signal processing may be altered, resulting in physical symptoms contributing to the development and/or maintenance of body-related mental disorders, which are associated with stress. In the current paper, we summarize findings on psychobiological processes underlying acute and chronic stress and their interaction with interoception. While focusing on the role of the physiological stress axes (HPA axis and autonomic nervous system, psychological factors in acute and chronic stress are also discussed. We propose a feed-forward model involving stress (in particular early life or chronic stress, as well as major adverse events, the dysregulation of physiological stress axes, altered perception of bodily sensations, and the generation of physical symptoms, which may in turn facilitate stress.

  14. Stress og aldring

    DEFF Research Database (Denmark)

    Jørgensen, Anders; Jørgensen, Martin Balslev; Poulsen, Henrik Enghusen

    2012-01-01

    Accumulating evidence supports the popular notion that psychological stress states may accelerate aging. Stress has been shown to influence cellular systems known to be involved in the aging process. Furthermore, stress is associated with an increased risk of various age-related medical disorders....... These effects are likely mediated by the secretion of stress hormones. In this short review we focus on biochemical and epidemiological evidence for a link between stress and aging....

  15. Occupational role stress is associated with higher cortisol reactivity to acute stress.

    Science.gov (United States)

    Wirtz, Petra H; Ehlert, Ulrike; Kottwitz, Maria U; La Marca, Roberto; Semmer, Norbert K

    2013-04-01

    We investigated whether occupational role stress is associated with differential levels of the stress hormone cortisol in response to acute psychosocial stress. Forty-three medication-free nonsmoking men aged between 22 and 65 years (mean ± SEM: 44.5 ± 2) underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience. We assessed occupational role stress in terms of role conflict and role ambiguity (combined into a measure of role uncertainty) as well as further work characteristics and psychological control variables including time pressure, overcommitment, perfectionism, and stress appraisal. Moreover, we repeatedly measured salivary cortisol and blood pressure levels before and after stress exposure, and several times up to 60 min thereafter. Higher role uncertainty was associated with a more pronounced cortisol stress reactivity (p = .016), even when controlling for the full set of potential confounders (p stress reactivity was not associated with role uncertainty. Our findings suggest that occupational role stress in terms of role uncertainty acts as a background stressor that is associated with increased HPA-axis reactivity to acute stress. This finding may represent a potential mechanism regarding how occupational role stress may precipitate adverse health outcomes.

  16. Neuroepigenetics of stress.

    Science.gov (United States)

    Griffiths, B B; Hunter, R G

    2014-09-05

    Stress, a common if unpredictable life event, can have pronounced effects on physiology and behavior. Individuals show wide variation in stress susceptibility and resilience, which are only partially explained by variations in coding genes. Developmental programing of the hypothalamic-pituitary-adrenal stress axis provides part of the explanation for this variance. Epigenetic approaches have successfully helped fill the explanatory gaps between the influences of gene and environment on stress responsiveness, and differences in the sequelae of stress across individuals and generations. Stress and the stress axis interacts bi-directionally with epigenetic marks within the brain. It is now clear that exposure to stress, particularly in early life, has both acute and lasting effects on these marks. They in turn influence cognitive function and behavior, as well as the risk for suicide and psychiatric disorders across the lifespan and, in some cases, unto future generations. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. Neutron diffraction measurements of residual stress in a powder metallurgy component

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Hainsworth, S.V.; Cocks, A.C.F.; Fitzpatrick, M.E.

    2005-01-01

    Residual stresses in a typical industrial green component were determined using neutron diffraction. The measured residual stresses were found to correlate with cross-sectional variations. Residual stress at the edge of the compact in contact with the die wall during compaction reached up to +80 MPa (tension) and -100 MPa (compression)

  18. Grit, anxiety, and stress in emergency physicians.

    Science.gov (United States)

    Wong, Matthew L; Anderson, Jared; Knorr, Thomas; Joseph, Joshua W; Sanchez, Leon D

    2018-02-26

    The personality traits of emergency physicians are infrequently studied, though interest in physician wellness is increasing. The objective of this study is to acquire pilot data about the amount of grit, anxiety, and stress in emergency physicians using established psychological survey instruments, and to examine their associations of each of these traits with each other. Thirty-six emergency medicine resident and attending physicians from an urban academic medical center consented for enrollment. Participants were administered the Duckworth 12-point Grit Scale, the State-Trait Anxiety Inventory (STAI), and the Perceived Stress Scale (PSS), which measure grit, anxiousness, and perceived stress, respectively. These are the gold standard psychological instruments for each of their areas. We analyzed the results with descriptive statistics, Spearman correlations, and linear regression. Nineteen residents and 17 attending physicians completed the surveys during the first quarter of a new academic year. The mean grit score was 3.7 (95% CI 3.5-3.8, SD: 0.56), the mean trait-anxiety score was 32.61 (95% CI 30.15-35.07, SD: 7.26), and the mean PSS score was 12.28 (95% CI 10.58-13.97, SD: 4.99). Only trait-anxiety and perceived stress were significantly correlated (Spearman's rho: 0.70, panxious reported more stress. Levels of grit were not associated with trait-anxiety. These psychological concepts should be studied further as they relate to the function and health of emergency medicine providers. Copyright © 2018. Published by Elsevier Inc.

  19. Effect of applied stress on the compressive residual stress introduced by laser peening

    International Nuclear Information System (INIS)

    Sumiya, Rie; Tazawa, Toshiyuki; Narazaki, Chihiro; Saito, Toshiyuki; Kishimoto, Kikuo

    2016-01-01

    Peening is the process which is able to be generated compressive residual stress and is known to be effective for preventing SCC initiation and improvement of fatigue strength. Laser peening is used for the nuclear power plant components in order to prevent SCC initiation. Although it is reported that the compressive residual stress decreases due to applied stresses under general operating condition, the change of residual stress might be large under excessive loading such as an earthquake. The objectives of this study are to evaluate the relaxation behavior of the compressive residual stress due to laser peening and to confirm the surface residual stress after loading. Therefore laser peened round bar test specimens of SUS316L which is used for the reactor internals of nuclear power plant were loaded at room temperature and elevated temperature and then surface residual stresses were measured by X-ray diffraction method. In the results of this test, it was confirmed that the compressive residual stress remained after applying uniform stress larger than 0.2% proof stress, and the effect of cyclic loading on the residual stress was small. The effect of applying compressive stress on the residual stress relaxation was confirmed to be less than that of applying tensile stress. Plastic deformation through a whole cross section causes the change in the residual stress distribution. As a result, the surface compressive residual stress is released. It was shown that the effect of specimen size on residual stress relaxation and the residual stress relaxation behavior in the stress concentration region can be explained by assumed stress relaxation mechanism. (author)

  20. Identification of resilient individuals and those at risk for performance deficits under stress.

    Science.gov (United States)

    Winslow, Brent D; Carroll, Meredith B; Martin, Jonathan W; Surpris, Glenn; Chadderdon, George L

    2015-01-01

    Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA) reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress.

  1. Serotonin-related gene expression in female monkeys with individual sensitivity to stress.

    Science.gov (United States)

    Bethea, C L; Streicher, J M; Mirkes, S J; Sanchez, R L; Reddy, A P; Cameron, J L

    2005-01-01

    Female cynomolgus monkeys exhibit different degrees of reproductive dysfunction with moderate metabolic and psychosocial stress. In this study, the expression of four genes pivotal to serotonin neural function was assessed in monkeys previously categorized as highly stress resistant (n=3; normal menstrual cyclicity through two stress cycles), medium stress resistant (n=5; ovulatory in the first stress cycle but anovulatory in the second stress cycle), or low stress resistant (i.e. stress-sensitive; n=4; anovulatory as soon as stress is initiated). In situ hybridization and quantitative image analysis was used to measure mRNAs coding for SERT (serotonin transporter), 5HT1A autoreceptor, MAO-A and MAO-B (monoamine oxidases) at six levels of the dorsal raphe nucleus (DRN). Optical density (OD) and positive pixel area were measured with NIH Image software. In addition, serotonin neurons were immunostained and counted at three levels of the DRN. Finally, each animal was genotyped for the serotonin transporter long polymorphic region (5HTTLPR). Stress sensitive animals had lower expression of SERT mRNA in the caudal region of the DRN (PMAO-A mRNA signal in the stress-sensitive group (PMAO-A OD was positively correlated with progesterone from a pre-stress control cycle (PMAO-B mRNA exhibited a similar downward trend in the stress-sensitive group. MAO-B OD also correlated with control cycle progesterone (PMAO-A) or exhibited a lower trend (5HT1A, MAO-B) in the stress sensitive animals, which probably reflects the lower number of serotonin neurons present.

  2. When does stress help or harm? The effects of stress controllability and subjective stress response on Stroop performance.

    Directory of Open Access Journals (Sweden)

    Roselinde Kaiser Henderson

    2012-06-01

    Full Text Available The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing to clinical therapy. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding tasks. In addition, research suggests that the impact of stress on cognitive functioning depends on an individual’s response to stressors: moderate responses to stress can lead to improved performance while extreme (high or low responses can lead to impaired performance. The present studies tested the hypothesis that 1 learning to behaviorally control stressors leads to improved performance on a test of general executive functioning, the color-word Stroop, and that 2 this improvement emerges specifically for people who report moderate (subjective responses to stress. Experiment 1: Stroop performance, measured before and after a stress manipulation, was compared across groups of undergraduate participants (n=109. People who learned to control a noise stressor and received accurate performance feedback demonstrated reduced Stroop interference compared with people exposed to uncontrollable noise stress and feedback indicating an exaggerated rate of failure. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest reduction in Stroop interference. In contrast, in the group exposed to uncontrollable events, self-reported stress failed to predict performance. Experiment 2: In a second sample (n=90, we specifically investigated the role of controllability by keeping the rate of failure feedback constant across groups. In the group who learned behavioral control, those who reported moderate levels of stress

  3. Development of the Family Stigma Stress Scale (FSSS) for Detecting Stigma Stress in Caregivers of People With Mental Illness.

    Science.gov (United States)

    Chang, Chih-Cheng; Su, Jian-An; Chang, Kun-Chia; Lin, Chung-Ying; Koschorke, Mirja; Rüsch, Nicolas; Thornicroft, Graham

    2017-01-01

    People with mental illness and their family caregivers often perceive public stigma, which may lead to stigma-related stress (or stigma stress). However, no instruments have been developed to measure this stress for family caregivers of people with mental illness. We modified an instrument that measures the stigma stress of people with mental illness (i.e., the cognitive appraisal of stigma as a stressor) and examined the psychometric properties of the scores of the newly developed instrument: the Family Stigma Stress Scale (FSSS). Primary family caregivers of people with mental illness in Southern Taiwan ( n = 300; mean age = 53.08 ± 13.80; 136 males) completed the FSSS. An exploratory factor analysis showed that the FSSS score had two factors; both factor scores had excellent internal consistency (α = .913 and .814) and adequate test-retest reliability ( r = .627 and .533; n = 197). Significant correlations between FSSS factor scores and other instruments supported its concurrent validity and the ability of the FSSS to differentiate between clinical characteristics, for example, having been previously hospitalized or not. The FSSS is a brief and effective measure of the stigma stress of family caregivers of people with mental illness.

  4. Extended Macroscopic Study of Dilute Gas Flow within a Microcavity

    Directory of Open Access Journals (Sweden)

    Mohamed Hssikou

    2016-01-01

    Full Text Available The behaviour of monatomic and dilute gas is studied in the slip and early transition regimes using the extended macroscopic theory. The gas is confined within a two-dimensional microcavity where the longitudinal sides are in the opposite motion with constant velocity ±Uw. The microcavity walls are kept at the uniform and reference temperature T0. Thus, the gas flow is transported only by the shear stress induced by the motion of upper and lower walls. From the macroscopic point of view, the regularized 13-moment equations of Grad, R13, are solved numerically. The macroscopic gas proprieties are studied for different values of the so-called Knudsen number (Kn, which gives the gas-rarefaction degree. The results are compared with those obtained using the classical continuum theory of Navier-Stokes and Fourier (NSF.

  5. FIB-based measurement of local residual stresses on microsystems

    Science.gov (United States)

    Vogel, Dietmar; Sabate, Neus; Gollhardt, Astrid; Keller, Juergen; Auersperg, Juergen; Michel, Bernd

    2006-03-01

    The paper comprises research results obtained for stress determination on micro and nanotechnology components. It meets the concern of controlling stresses introduced to sensors, MEMS and electronics devices during different micromachining processes. The method bases on deformation measurement options made available inside focused ion beam equipment. Removing locally material by ion beam milling existing stresses / residual stresses lead to deformation fields around the milled feature. Digital image correlation techniques are used to extract deformation values from micrographs captured before and after milling. In the paper, two main milling features have been analyzed - through hole and through slit milling. Analytical solutions for stress release fields of in-plane stresses have been derived and compared to respective experimental findings. Their good agreement allows to settle a method for determination of residual stress values, which is demonstrated for thin membranes manufactured by silicon micro technology. Some emphasis is made on the elimination of main error sources for stress determination, like rigid body object displacements and rotations due to drifts of experimental conditions under FIB imaging. In order to illustrate potential application areas of the method residual stress suppression by ion implantation is evaluated by the method and reported here.

  6. High-resolution stress measurements for microsystem and semiconductor applications

    Science.gov (United States)

    Vogel, Dietmar; Keller, Juergen; Michel, Bernd

    2006-04-01

    Research results obtained for local stress determination on micro and nanotechnology components are summarized. It meets the concern of controlling stresses introduced to sensors, MEMS and electronics devices during different micromachining processes. The method bases on deformation measurement options made available inside focused ion beam equipment. Removing locally material by ion beam milling existing stresses / residual stresses lead to deformation fields around the milled feature. Digital image correlation techniques are used to extract deformation values from micrographs captured before and after milling. In the paper, two main milling features have been analyzed - through hole and through slit milling. Analytical solutions for stress release fields of in-plane stresses have been derived and compared to respective experimental findings. Their good agreement allows to settle a method for determination of residual stress values, which is demonstrated for thin membranes manufactured by silicon micro technology. Some emphasis is made on the elimination of main error sources for stress determination, like rigid body object displacements and rotations due to drifts of experimental conditions under FIB imaging. In order to illustrate potential application areas of the method residual stress suppression by ion implantation is evaluated by the method and reported here.

  7. The effect of occupational stress, psychological stress and burnout on employee performance: Evidence from banking industry

    Directory of Open Access Journals (Sweden)

    Shahram Hashemnia

    2014-09-01

    Full Text Available This paper presents an empirical investigation on the effects of occupational stress, psychological stress as well as job burnout on women’s employee performance in city of Karaj, Iran. The proposed study designs a questionnaire in Likert scale and distributes it among all female employees who worked for Bank Maskan in this city. In our survey, employee performance consists of three parts of interpersonal performance, job performance as well as organizational performance. Cronbach alpha has been used to verify the overall questionnaire, all components were within acceptable levels, and the implementation of Kolmogorov-Smirnov test has indicated that the data were not normally distributed. Using Spearman correlation ratio as well as regression techniques, the study has determined that while psychological stress influenced significantly on all three components of employee performance including interpersonal performance, job performance as well as organizational performance, the effect on job performance was greater than the other components. In addition, occupational stress only influences on organizational as well as interpersonal performance. Finally, employee burnout has no impact on any components of employee performance.

  8. Stress and its molecular consequences in cancer progression

    Directory of Open Access Journals (Sweden)

    Magdalena Surman

    2017-06-01

    Full Text Available Stress, caused by psychological, physiological and physical factors has an adverse impact on human body homeostasis. There are two kind of stress: short-term and chronic. Cancer patients usually live under chronic stress, caused by diagnosis-related strong emotional experience and depression, resulting from various difficulties associated with disease progression and treatment. At the molecular level, stress factors induce production and secretion of stress-related hormones, such as catecholamines, glucocorticoids and dopamine (as a part of adaptational body response, which influence both normal and transformed cells through their specific receptors. The particular effects exerted by these molecules on cancer cells have been also observed in in vitro cultures and include changes in proliferation, apoptosis susceptibility and migration/invasion potential. As a result, it has been suggested that stress hormones may be responsible for progression of malignancy and thus accelerate the metastasis formation in cancer patients. However, the clinical data on correlation between stress and the patients survival, as well as the molecular analysis of stress hormone receptors expression and action in cancer cell, have not yet provided an unequivocal answer. For this reason, extensive studies, on molecular and clinical level are needed to fully determine stress impact on cancerprogression and on the effectiveness of anti-cancer treatment. Nowadays, it seems reasonable that the personalization of anti-cancer therapy should also focus on mental state of cancer patients, and provide them with psychological tools or techniques for stress management.

  9. Impulsivity and Stress Response in Pathological Gamblers During the Trier Social Stress Test.

    Science.gov (United States)

    Maniaci, G; Goudriaan, A E; Cannizzaro, C; van Holst, R J

    2018-03-01

    Gambling has been associated with increased sympathetic nervous system output and stimulation of the hypothalamic-pituitary-adrenal axis. However it is unclear how these systems are affected in pathological gambling. This study aimed to investigate the effect of the Trier Social Stress Test (TSST) on cortisol and on cardiac interbeat intervals in relation to impulsivity, in a sample of male pathological gamblers compared to healthy controls. In addition, we investigated the correlation between the TSST, duration of the disorder and impulsivity. A total of 35 pathological gamblers and 30 healthy controls, ranging from 19 to 58 years old and all male, participated in this study. Stress response was measured during and after the TSST by salivary cortisol and cardiac interbeat intervals; impulsivity was assessed with the Barratt Impulsiveness Scale (BIS-11). Exposure to the TSST produced a significant increase in salivary cortisol and interbeat intervals in both groups, without differences between groups. We found a negative correlation between baseline cortisol and duration of pathological gambling indicating that the longer the duration of the disorder the lower the baseline cortisol levels. Additionally, we found a main effect of impulsivity across groups on interbeat interval during the TSST, indicating an association between impulsivity and the intensity of the neurovegetative stress response during the TSST. Involvement of the hypothalamic-pituitary-adrenal axis in pathological gambling was confirmed together with evidence of a correlation between length of the disorder and diminished baseline cortisol levels. Impulsivity emerged as a personality trait expressed by pathological gamblers; however the neurovegetative response to the TSST, although associated with impulsivity, appeared to be independent of the presence of pathological gambling.

  10. How Do You #relax When You're #stressed? A Content Analysis and Infodemiology Study of Stress-Related Tweets.

    Science.gov (United States)

    Doan, Son; Ritchart, Amanda; Perry, Nicholas; Chaparro, Juan D; Conway, Mike

    2017-06-13

    Stress is a contributing factor to many major health problems in the United States, such as heart disease, depression, and autoimmune diseases. Relaxation is often recommended in mental health treatment as a frontline strategy to reduce stress, thereby improving health conditions. Twitter is a microblog platform that allows users to post their own personal messages (tweets), including their expressions about feelings and actions related to stress and stress management (eg, relaxing). While Twitter is increasingly used as a source of data for understanding mental health from a population perspective, the specific issue of stress-as manifested on Twitter-has not yet been the focus of any systematic study. The objective of our study was to understand how people express their feelings of stress and relaxation through Twitter messages. In addition, we aimed at investigating automated natural language processing methods to (1) classify stress versus nonstress and relaxation versus nonrelaxation tweets, and (2) identify first-hand experience-that is, who is the experiencer-in stress and relaxation tweets. We first performed a qualitative content analysis of 1326 and 781 tweets containing the keywords "stress" and "relax," respectively. We then investigated the use of machine learning algorithms-in particular naive Bayes and support vector machines-to automatically classify tweets as stress versus nonstress and relaxation versus nonrelaxation. Finally, we applied these classifiers to sample datasets drawn from 4 cities in the United States (Los Angeles, New York, San Diego, and San Francisco) obtained from Twitter's streaming application programming interface, with the goal of evaluating the extent of any correlation between our automatic classification of tweets and results from public stress surveys. Content analysis showed that the most frequent topic of stress tweets was education, followed by work and social relationships. The most frequent topic of relaxation tweets

  11. Impact of psychological stress on irritable bowel syndrome.

    Science.gov (United States)

    Qin, Hong-Yan; Cheng, Chung-Wah; Tang, Xu-Dong; Bian, Zhao-Xiang

    2014-10-21

    Psychological stress is an important factor for the development of irritable bowel syndrome (IBS). More and more clinical and experimental evidence showed that IBS is a combination of irritable bowel and irritable brain. In the present review we discuss the potential role of psychological stress in the pathogenesis of IBS and provide comprehensive approaches in clinical treatment. Evidence from clinical and experimental studies showed that psychological stresses have marked impact on intestinal sensitivity, motility, secretion and permeability, and the underlying mechanism has a close correlation with mucosal immune activation, alterations in central nervous system, peripheral neurons and gastrointestinal microbiota. Stress-induced alterations in neuro-endocrine-immune pathways acts on the gut-brain axis and microbiota-gut-brain axis, and cause symptom flare-ups or exaggeration in IBS. IBS is a stress-sensitive disorder, therefore, the treatment of IBS should focus on managing stress and stress-induced responses. Now, non-pharmacological approaches and pharmacological strategies that target on stress-related alterations, such as antidepressants, antipsychotics, miscellaneous agents, 5-HT synthesis inhibitors, selective 5-HT reuptake inhibitors, and specific 5-HT receptor antagonists or agonists have shown a critical role in IBS management. A integrative approach for IBS management is a necessary.

  12. Reliability of Coulomb stress changes inferred from correlated uncertainties of finite-fault source models

    KAUST Repository

    Woessner, J.

    2012-07-14

    Static stress transfer is one physical mechanism to explain triggered seismicity. Coseismic stress-change calculations strongly depend on the parameterization of the causative finite-fault source model. These models are uncertain due to uncertainties in input data, model assumptions, and modeling procedures. However, fault model uncertainties have usually been ignored in stress-triggering studies and have not been propagated to assess the reliability of Coulomb failure stress change (ΔCFS) calculations. We show how these uncertainties can be used to provide confidence intervals for co-seismic ΔCFS-values. We demonstrate this for the MW = 5.9 June 2000 Kleifarvatn earthquake in southwest Iceland and systematically map these uncertainties. A set of 2500 candidate source models from the full posterior fault-parameter distribution was used to compute 2500 ΔCFS maps. We assess the reliability of the ΔCFS-values from the coefficient of variation (CV) and deem ΔCFS-values to be reliable where they are at least twice as large as the standard deviation (CV ≤ 0.5). Unreliable ΔCFS-values are found near the causative fault and between lobes of positive and negative stress change, where a small change in fault strike causes ΔCFS-values to change sign. The most reliable ΔCFS-values are found away from the source fault in the middle of positive and negative ΔCFS-lobes, a likely general pattern. Using the reliability criterion, our results support the static stress-triggering hypothesis. Nevertheless, our analysis also suggests that results from previous stress-triggering studies not considering source model uncertainties may have lead to a biased interpretation of the importance of static stress-triggering.

  13. [Measurement of unemployment-related psychological stress: Validation of the Unemployment Stress (USS)].

    Science.gov (United States)

    Szabóné Kapuvári, Virág; Martos, Tamás

    2016-01-01

    Nowadays the theme of unemployment and the given answers of it are up to date questions in psychology. In spite of this fact, the psychological methods measuring this phenomenon are often missing. That is why the Unemployment Stress Scale (USS) is presented in this article. The aim of our study is to develop a scale called USS and test it's validity and reliability. There were 287 adult unemployed persons asked in this study. Besides the USS we used the Beck Depression Scale, the Spielberger Anxiety Scale (TRAIT), the Sense of Coherence Scale (Hungarian version) and the Rosenberg Self Esteem Scale. According to our results, USS has showed an excellent criterion and construct validity. A useful scale has been formed according to test-retest results. (Cronbach-alfa: 0.88 and 0.86 according to the samples). Moreover our scale has a strong correlation with the Spielberger Anxiety Scale (TRAIT) and the Beck Depression Scale. These chracteristics of the new scale proved that we fond a factor, independent from the self esteem and the sense of coherence, which represents the stress level in the situation of unemployment. This scale is a professional construction to measure stress contributed to unemployment. The USS can be a useful scale in clinical practice because after measuring with this scale we can protect the personality of the unemployed by representing the actual unemployment stress level. That is why professionals can help earlier in a crisis like this.

  14. Emergence Time and Skin Melanin Spot Patterns Do Not Correlate with Growth Performance, Social Competitive Ability or Stress Response in Farmed Rainbow Trout.

    Science.gov (United States)

    Gesto, Manuel; Skov, Peter V; Jokumsen, Alfred

    2017-01-01

    In wild salmonid fish, specific individual behavioral traits have been correlated with the timing of fry emergence from their gravel spawning nests; Early emerging fish display more aggressive behavior and have a higher probability of becoming socially dominant, compared to fish that emerge at a later stage. Apart from aggression and dominance, other behavioral and metabolic traits, such as boldness, metabolic rate, or growth, have also been linked to emergence time. Altogether, the traits of early- and late-emerging fish resemble those of the proactive and reactive stress-coping style, respectively. As proactive fish are considered more resilient to stress, it may be desirable to select these for aquaculture production. However, it is currently unclear to what extent the link between emergence time and stress-coping styles is maintained in the selective breeding of farmed fish. In the present study, eyed eggs from a commercial supplier were hatched, and larvae fractionated according to their emergence time. Later on, juvenile fish from different emergence fractions were subjected to a stress challenge and also tested to evaluate their competitive ability for food. Beyond some slight dissimilarities in the acute stress responses, emergence fraction displayed no correlation with growth rates, or the ability to compete for feed. Within the whole group of fish utilized in the experiments, no relationship between skin melanin spot pattern and growth performance, stress response intensity, or competitive ability was found. Altogether, the differences in physiological traits related to emergence time were not as strong as those found in earlier studies. It is hypothesized, that the origin and degree of domestication of the fish might be partly responsible for this. The predictive value of skin spots or emergence time to infer the fish stress coping style in farmed fish is also discussed.

  15. Emergence Time and Skin Melanin Spot Patterns Do Not Correlate with Growth Performance, Social Competitive Ability or Stress Response in Farmed Rainbow Trout

    Directory of Open Access Journals (Sweden)

    Manuel Gesto

    2017-06-01

    Full Text Available In wild salmonid fish, specific individual behavioral traits have been correlated with the timing of fry emergence from their gravel spawning nests; Early emerging fish display more aggressive behavior and have a higher probability of becoming socially dominant, compared to fish that emerge at a later stage. Apart from aggression and dominance, other behavioral and metabolic traits, such as boldness, metabolic rate, or growth, have also been linked to emergence time. Altogether, the traits of early- and late-emerging fish resemble those of the proactive and reactive stress-coping style, respectively. As proactive fish are considered more resilient to stress, it may be desirable to select these for aquaculture production. However, it is currently unclear to what extent the link between emergence time and stress-coping styles is maintained in the selective breeding of farmed fish. In the present study, eyed eggs from a commercial supplier were hatched, and larvae fractionated according to their emergence time. Later on, juvenile fish from different emergence fractions were subjected to a stress challenge and also tested to evaluate their competitive ability for food. Beyond some slight dissimilarities in the acute stress responses, emergence fraction displayed no correlation with growth rates, or the ability to compete for feed. Within the whole group of fish utilized in the experiments, no relationship between skin melanin spot pattern and growth performance, stress response intensity, or competitive ability was found. Altogether, the differences in physiological traits related to emergence time were not as strong as those found in earlier studies. It is hypothesized, that the origin and degree of domestication of the fish might be partly responsible for this. The predictive value of skin spots or emergence time to infer the fish stress coping style in farmed fish is also discussed.

  16. The Effect of Stress Management on Occupational Stress and Satisfaction among Midwives in Obstetrics and Gynecology Hospital Wards in Iran.

    Science.gov (United States)

    Karimyar Jahromi, Mahdi; Minaei, Shahnaz; Abdollahifard, Sareh; Maddahfar, Majid

    2016-09-01

    Occupational stress is one of the major problems of health care staff, substantially affecting their professional and personal performance. This research has been conducted with the aim of determining the effect of stress management on occupational stress and satisfaction among the Midwives in Obstetrics and Gynecology Hospital wards at Motahari Hospital in Jahrom, Iran 2013-2014. This is a Quasi-experimental study of the pre- and post-clinical trials type. The study population included midwives employed in the Obstetrics and Gynecology Hospital wards selected trough census. The samples were categorized into two groups randomly. The intervention group participated in the short-term training workshop of stress management. The studied samples were measured in terms of occupational stress and satisfaction before, right after, and one month after the workshop. Occupational stress measurement was measured by Toft-Anderson occupational stress questionnaire (1981). Similarly, the occupational satisfaction was measured by JDI checklist developed by Stephen Robins (1994). In order to analyze the information, SPSS 16 together with descriptive statistics tests (frequency, percentile, mean, and standard deviation), independent sample t-tests, iterative measurement and Spearman correlation coefficient were used.  A total of 70 people (two 35-person groups) of midwives participated in this study. The findings revealed that there was a significant difference between the mean of scores of occupational stress between the two groups before and after the workshop (p=0.001). There was, however, no significant difference between the scores of satisfactions across the two groups. Training of skills of coping with stress including stress management can be effective in diminishing level of occupational stress. Mitigation of stress without catering for professional, occupational, organizational, and environmental factors would not lead to development of job satisfaction.

  17. In stressful company – Changes in stress and work ties over time

    DEFF Research Database (Denmark)

    Waldstrøm, Christian; Parker, Andrew; Shah, Neha P.

    Recent research on stress and burnout has highlighted the collective aspects of stress symptoms, perceived stress, and coping mechanisms. Much of this work, however, is focused on group and team dynamics rather than how network factors shape individuals’ feelings of stress and burnout. We use...... a stress questionnaire and social network analysis at three time points in a Scandinavian biotechnology company to examine the interactions between stress and relationship development and maintenance over time. We show that individuals tend to form and maintain ties to people who are less stressed than...... they are, indicating that while misery might love company, stress does not. Given the longitudinal nature of the study, we’re able to disentangle the causal effects....

  18. Long interspersed nuclear element-1 hypomethylation and oxidative stress: correlation and bladder cancer diagnostic potential.

    Directory of Open Access Journals (Sweden)

    Maturada Patchsung

    Full Text Available Although, increased oxidative stress and hypomethylation of long interspersed nuclear element-1 (LINE-1 associate with bladder cancer (BCa development, the relationship between these alterations is unknown. We evaluated the oxidative stress and hypomethylation of the LINE-1 in 61 BCa patients and 45 normal individuals. To measure the methylation levels and to differentiate the LINE-1 loci into hypermethylated, partially methylated and hypomethylated, peripheral blood cells, urinary exfoliated cells and cancerous tissues were evaluated by combined bisulfite restriction analysis PCR. The urinary total antioxidant status (TAS and plasma protein carbonyl content were determined. The LINE-1 methylation levels and patterns, especially hypomethylated loci, in the blood and urine cells of the BCa patients were different from the levels and patterns in the healthy controls. The urinary TAS was decreased, whereas the plasma protein carbonyl content was increased in the BCa patients relative to the controls. A positive correlation between the methylation of LINE-1 in the blood-derived DNA and urinary TAS was found in both the BCa and control groups. The urinary hypomethylated LINE-1 loci and the plasma protein carbonyl content provided the best diagnostic potential for BCa prediction. Based on post-diagnostic samples, the combination test improved the diagnostic power to a sensitivity of 96% and a specificity of 96%. In conclusion, decreased LINE-1 methylation is associated with increased oxidative stress both in healthy and BCa subjects across the various tissue types, implying a dose-response association. Increases in the LINE-1 hypomethylation levels and the number of hypomethylated loci in both the blood- and urine-derived cells and increase in the oxidative stress were found in the BCa patients. The combination test of the urinary hypomethylated LINE-1 loci and the plasma protein carbonyl content may be useful for BCa screening and monitoring of

  19. Correlation of serum vitamin E content with insulin resistance and oxidative stress response in patients with type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Jun Li

    2017-08-01

    Full Text Available Objective: To study the correlation of serum vitamin E content with insulin resistance and oxidative stress response in patients with type 2 diabetes mellitus. Methods: Patients who were diagnosed with type 2 diabetes mellitus in Xining Second People’s Hospital between February 2016 and February 2017 were selected as T2DM group, healthy volunteers who received physical examination during the same period were selected as control group, oral glucose tolerance test was conducted to detect insulin resistance indexes, and fasting venous blood was collected to detect oxidative stress indicators. Results: Serum VitE, 2 h-Ins, 2 h-CP, Trx, Txnip, SOD and GSH-Px levels of T2DM group were significantly lower than those of control group while F-Ins, F-CP, MDA, AOPP, 8-OHdG, AGEs and LOX-1 levels were significantly higher than those of control group; serum VitE level in T2DM patients was positively correlated with serum 2 h-Ins, 2 h-CP, Trx, Txnip, SOD and GSH-Px levels, and negatively correlated with serum F-Ins, F-CP, MDA, AOPP, 8-OHdG, AGEs and LOX-1 levels. Conclusion: The decrease of serum vitamin E in patients with type 2 diabetes mellitus can lead to the aggravation of insulin resistance and the activation of oxidative stress response.

  20. Stressed Out: How Stress Develops and How to Cope with it

    Directory of Open Access Journals (Sweden)

    Mortillaro Marcello

    2014-05-01

    Full Text Available Our experience of stress depends on how we evaluate the circumstances impacting our individual well-being. In principle, any event can be a stressor. Certain events can produce complex emotional states, such as a mixture of anger and worry. If such states are prolonged, they can lead to stress. Stress can be identified by means of such expressive components as facial expression and signs of stress in the voice. Indeed, the voice is particularly sensitive to stress and is frequently used to measure stress levels. Coping strategies differ from person to person and are not mutually exclusive. Often, people use multiple strategies at the same time. Not all of these strategies are good for individual well-being or favor a cooperation-based work culture. To avoid employee burnout, companies should keep an eye on the stress load of their employees and develop trainings to increase emotional competences and improve constructive stress management.

  1. Preferential loss of dorsal-hippocampus synapses underlies memory impairments provoked by short, multimodal stress.

    Science.gov (United States)

    Maras, P M; Molet, J; Chen, Y; Rice, C; Ji, S G; Solodkin, A; Baram, T Z

    2014-07-01

    The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress.

  2. Preferential loss of dorsal-hippocampus synapses underlies memory impairments provoked by short, multimodal stress

    Science.gov (United States)

    Maras, P M; Molet, J; Chen, Y; Rice, C; Ji, S G; Solodkin, A; Baram, T Z

    2014-01-01

    The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress. PMID:24589888

  3. Geopotential Stress

    DEFF Research Database (Denmark)

    Schiffer, Christian; Nielsen, S.B.

    Density heterogeneity in the Earth’s lithosphere causes lateral pressure variations. Horizontal gradients of the vertically integrated lithostatic pressure, the Geopotential Energy (GPE), are a source of stresses (Geopotential Stress) that contribute to the Earth’s Stress Field. In theory the GPE...... is linearly related to the lithospheric part of the Geoid. The Geopotential Stress can be calculated if either the density structure and as a consequence the GPE or the lithospheric contribution to the Geoid is known. The lithospheric Geoid is usually obtained by short pass filtering of satellite Geoid...... are not entirely suitable for the stress calculations but can be compiled and adjusted. We present an approach in which a global lithospheric density model based on CRUST2.0 is obtained by simultaneously fitting topography and surface heat flow in the presence of isostatic compensation and long-wavelength lateral...

  4. [Stress in surgeries].

    Science.gov (United States)

    Daian, Márcia Rodrigues; Petroianu, Andy; Alberti, Luiz Ronaldo; Jeunon, Ester Eliane

    2012-01-01

    The purpose of this article was to provide the literature regarding the psychological stress in the peri-operative period of adult patients undergoing operations under general anesthesia. The articles were obtained by surveying the papers published and catalogued in the Medline Pubmed interface database, Lilacs and the Biblioteca Virtual de Saúde (BVS) since 1984, crossing the headings stress, surgery, general anesthesia, psychology. Over 800 articles related to stress and surgery were analyzed with regards to their relevance to the considered subject. Eighteen articles were related to psychological stress. Their results confirmed the presence of psychological and physical stress, during the peri-operative period as well as relation between stress and de clinical post-operative recovery. There is a gap regarding in the peri-operative period. More studies on psychological influence on stress may benefit patients and help professionals during the surgical treatment.

  5. Correlates of Cortisol in Human Hair: Implications for Epidemiologic Studies on Health Effects of Chronic Stress

    Science.gov (United States)

    Wosu, Adaeze C.; Valdimarsdóttir, Unnur; Shields, Alexandra E.; Williams, David R.; Williams, Michelle A.

    2013-01-01

    Assessment of cortisol concentrations in hair is one of the latest innovations for measuring long-term cortisol exposure. We performed a systematic review of correlates of cortisol in human hair to inform the design, analysis and interpretation of future epidemiologic studies. Relevant publications were identified through electronic searches on PubMed, WorldCat, and Web of Science using keywords, “cortisol” “hair” “confounders” “chronic” “stress” and “correlates.” Thirty-nine studies were included in this review. Notwithstanding scarce data and some inconsistencies, investigators have found hair cortisol concentrations to be associated with stress-related psychiatric symptoms and disorders (e.g., PTSD), medical conditions indicating chronic activation of the hypothalamic-pituitary-adrenal axis (e.g., Cushing´s syndrome) and other life situations associated with elevated risk of chronic stress (e.g., shiftwork). Results from some studies suggest that physical activity, adiposity, and substance abuse may be correlates of hair cortisol concentrations. In contrast to measures of short-term cortisol release (saliva, blood, and urine), cigarette smoking and use of oral contraceptives appear to not be associated with hair cortisol concentrations. Studies of pregnant women indicate increased hair cortisol concentrations across successive trimesters. The study of hair cortisol presents a unique opportunity to assess chronic alterations in cortisol concentrations in epidemiologic studies. PMID:24184029

  6. Correlation of EPO resistance with oxidative stress response and inflammatory response in patients with maintenance hemodialysis

    Directory of Open Access Journals (Sweden)

    Xiao-Hui Yan

    2017-08-01

    Full Text Available Objective: To study the correlation of erythropoietin (EPO resistance with oxidative stress response and inflammatory response in patients with maintenance hemodialysis. Methods: A total of 184 patients with end-stage renal disease who received maintenance hemodialysis in Shaanxi Provincial People’s Hospital between March 2015 and October 2016 were selected as dialysis group, 102 volunteers who received physical examination in Shaanxi Provincial People’s Hospital during the same period were selected as control group, the EPO resistance index was assessed, the median was calculated, and serum oxidative stress and inflammatory response indexes were detected. Results: Serum T-AOC, SOD and CAT levels in dialysis group were significantly lower than those in control group while MDA, AOPP, IFN-γ, HMGB-1, ICAM-1, IL-4 and IL-10 levels were significantly higher than those in control group; serum T-AOC, SOD and CAT levels in patients with high ERI were significantly lower than those in patients with low ERI while MDA, AOPP, IFN-γ, HMGB-1, ICAM-1, IL-4 and IL-10 levels were significantly higher than those in patients with low ERI. Conclusion: The degree of EPO resistance in patients with maintenance hemodialysis is closely related to the activation of oxidative stress response and inflammatory response.

  7. Transient thermal stresses in a transversely isotropic finite hollow circular cylinder due to arbitrary surface heat generations

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro; Nakanishi, Takanori.

    1980-01-01

    The materials macroscopically regarded as anisotropic materials such as fiber-reinforced composite materials have become to be used for the structural elements at elevated temperature, and the studies on the problem of thermal stress in anisotropic bodies are carried out actively. The unsteady thermal stress in anisotropic finite circular cylinders has not been analyzed so far. In this study, the problem of unsteady thermal stress in an anisotropic finite circular cylinder having arbitrary surface heat generation in axial direction on the internal and external surfaces, and emitting heat from both ends and the internal and external surfaces, was analyzed. For the analysis of temperature distribution, generalized finite Fourier transformation and finite Hankel transformation were used, and thermal stress and thermal displacement were analyzed by the use of the stress function of Singh. By adopting the function used for the transformation nucleus in generalized finite Fourier transformation as the stress function, the analysis was made without separating symmetric and opposite symmetric problems. Numerical calculation was carried out on the basis of the analytical results, and the effects of the anisotropy in thermal conductivity, Young's modulus and linear expansion on unsteady temperature distribution, thermal stress and thermal displacement were quantitatively examined. (Kako, I.)

  8. Characteristics of people with self-reported stress-precipitated seizures.

    Science.gov (United States)

    Privitera, Michael; Walters, Michael; Lee, Ikjae; Polak, Emily; Fleck, Adrienne; Schwieterman, Donna; Haut, Sheryl R

    2014-12-01

    Stress is the most common patient-reported seizure precipitant. We aimed to determine mood and epilepsy characteristics of people who report stress-precipitated seizures. Sequential patients at a tertiary epilepsy center were surveyed about stress as a seizure precipitant. We asked whether acute (lasting minutes-hours) or chronic (lasting days-months) stress was a seizure precipitant, whether stress reduction had been tried, and what effect stress reduction had on seizure frequency. We collected information on antiepileptic drugs, history of depression and anxiety disorder, prior or current treatment for depression or anxiety, and scores on the Neurological Disorders Depression Inventory (NDDI-E) and Generalized Anxiety Disorders-7 (GAD-7) instruments, which are administered at every visit in our Epilepsy Center. We also asked whether respondents thought that they could predict their seizures to determine if stress as a seizure precipitant was correlated with seizure self-prediction. Two hundred sixty-six subjects were included: 219 endorsed stress as a seizure precipitant [STRESS (+)] and 47 did not [STRESS (-)]. Among STRESS (+) subjects, 85% endorsed chronic stress as a seizure precipitant, and 68% endorsed acute stress as a seizure precipitant. In STRESS (+) subjects, 57% had used some type of relaxation or stress reduction method (most commonly yoga, exercise and meditation), and, of those who tried, 88% thought that these methods improved seizures. Among STRESS (-) subjects, 25% had tried relaxation or stress reduction, and 71% thought that seizures improved. Although univariate analysis showed multiple associations with stress as a seizure precipitant, in the multivariable logistic regression, only the GAD-7 score was associated with STRESS (+) (OR = 1.18 [1.03-1.35], p = 0.017). Subjects who reported stress as a seizure precipitant were more likely to report an ability to self-predict seizures (p < 0.001). Stress-precipitated seizures are commonly reported

  9. Affective temperament, job stress and professional burnout in nurses and civil servants.

    Science.gov (United States)

    Jaracz, Marcin; Rosiak, Izabela; Bertrand-Bucińska, Anna; Jaskulski, Maciej; Nieżurawska, Joanna; Borkowska, Alina

    2017-01-01

    The risk of professional burnout is constituted by job-related as well as individual factors. The latter involve affective temperament, which influences the perception of job-related stress. The aim of the present study was to assess the affective temperament, the level of job stress and professional burnout, as well as the relationships between these variables, in public servants and nurses. 100 civil servants and 100 nurses were enrolled in the study. Affective temperament and burnout were assessed by means of TEMPS-A and MBI questionnaires, respectively. To measure the level of job-related stress, we have designed a 6-item self-reported questionnaire, which considered stressors common for both professions. Compared to the civil servants, nurses showed higher rate of anxious temperament and experienced greater intensity of job-related stress. The groups did not differ in the intensity of burnout symptoms. The rates of cyclothymic and anxious temperaments correlated with the intensity of stress, and burnout symptoms in the group of nurses. Within the civil servants group, the level of stress correlated with intensity of burnout, however no correlations with affective temperament were observed. The regression analysis performed in both groups revealed the significant effect of stress and cyclothymic temperament on burnout, while the effect of anxious temperament was not significant. Cyclothymic and anxious temperaments are related to the level of experienced job stress and the risk of burnout. In professions like nursing, where employees show elevated rates of these temperaments, burnout prevention and stress management education is of particular importance.

  10. Affective temperament, job stress and professional burnout in nurses and civil servants.

    Directory of Open Access Journals (Sweden)

    Marcin Jaracz

    Full Text Available The risk of professional burnout is constituted by job-related as well as individual factors. The latter involve affective temperament, which influences the perception of job-related stress. The aim of the present study was to assess the affective temperament, the level of job stress and professional burnout, as well as the relationships between these variables, in public servants and nurses.100 civil servants and 100 nurses were enrolled in the study. Affective temperament and burnout were assessed by means of TEMPS-A and MBI questionnaires, respectively. To measure the level of job-related stress, we have designed a 6-item self-reported questionnaire, which considered stressors common for both professions.Compared to the civil servants, nurses showed higher rate of anxious temperament and experienced greater intensity of job-related stress. The groups did not differ in the intensity of burnout symptoms. The rates of cyclothymic and anxious temperaments correlated with the intensity of stress, and burnout symptoms in the group of nurses. Within the civil servants group, the level of stress correlated with intensity of burnout, however no correlations with affective temperament were observed. The regression analysis performed in both groups revealed the significant effect of stress and cyclothymic temperament on burnout, while the effect of anxious temperament was not significant.Cyclothymic and anxious temperaments are related to the level of experienced job stress and the risk of burnout. In professions like nursing, where employees show elevated rates of these temperaments, burnout prevention and stress management education is of particular importance.

  11. The Yeast Environmental Stress Response Regulates Mutagenesis Induced by Proteotoxic Stress

    Science.gov (United States)

    Shor, Erika; Fox, Catherine A.; Broach, James R.

    2013-01-01

    Conditions of chronic stress are associated with genetic instability in many organisms, but the roles of stress responses in mutagenesis have so far been elucidated only in bacteria. Here, we present data demonstrating that the environmental stress response (ESR) in yeast functions in mutagenesis induced by proteotoxic stress. We show that the drug canavanine causes proteotoxic stress, activates the ESR, and induces mutagenesis at several loci in an ESR-dependent manner. Canavanine-induced mutagenesis also involves translesion DNA polymerases Rev1 and Polζ and non-homologous end joining factor Ku. Furthermore, under conditions of chronic sub-lethal canavanine stress, deletions of Rev1, Polζ, and Ku-encoding genes exhibit genetic interactions with ESR mutants indicative of ESR regulating these mutagenic DNA repair processes. Analyses of mutagenesis induced by several different stresses showed that the ESR specifically modulates mutagenesis induced by proteotoxic stress. Together, these results document the first known example of an involvement of a eukaryotic stress response pathway in mutagenesis and have important implications for mechanisms of evolution, carcinogenesis, and emergence of drug-resistant pathogens and chemotherapy-resistant tumors. PMID:23935537

  12. Oxidative stress associated with exercise, psychological stress and life-style factors

    DEFF Research Database (Denmark)

    Møller, P; Wallin, H; Knudsen, Lisbeth E.

    1996-01-01

    generation. Here, we review the effect of alcohol, air pollution, cigarette smoke, diet, exercise, non-ionizing radiation (UV and microwaves) and psychological stress on the development of oxidative stress. Regular exercise and carbohydrate-rich diets seem to increase the resistance against oxidative stress....... Air pollution, alcohol, cigarette smoke, non-ionizing radiation and psychological stress seem to increase oxidative stress. Alcohol in lower doses may act as an antioxidant on low density lipoproteins and thereby have an anti-atherosclerotic property....

  13. Stress alters personal moral decision making.

    Science.gov (United States)

    Youssef, Farid F; Dookeeram, Karine; Basdeo, Vasant; Francis, Emmanuel; Doman, Mekaeel; Mamed, Danielle; Maloo, Stefan; Degannes, Joel; Dobo, Linda; Ditshotlo, Phatsimo; Legall, George

    2012-04-01

    While early studies of moral decision making highlighted the role of rational, conscious executive processes involving frontal lobe activation more recent work has suggested that emotions and gut reactions have a key part to play in moral reasoning. Given that stress can activate many of the same brain regions that are important for and connected to brain centres involved in emotional processing we sought to evaluate if stress could influence moral decision making. Sixty-five undergraduate volunteers were randomly assigned to control (n=33) and experimental groups (n=32). The latter underwent the Trier Social Stress Test (TSST) and induction of stress was assessed by measurement of salivary cortisol levels. Subjects were then required to provide a response to thirty moral dilemmas via a computer interface that recorded both their decision and reaction time. Three types of dilemmas were used: non-moral, impersonal moral and personal moral. Using a binary logistic model there were no significant predicators of utilitarian response in non-moral and impersonal moral dilemmas. However the stressed group and females were found to predict utilitarian responses to personal moral dilemmas. When comparing percentage utilitarian responses there were no significant differences noted for the non-moral and impersonal moral dilemmas but the stressed group showed significantly less utilitarian responses compared to control subjects. The stress response was significantly negatively correlated with utilitarian responses. Females also showed significantly less utilitarian responses than males. We conclude that activation of the stress response predisposed participants to less utilitarian responses when faced with high conflict personal moral dilemmas and suggest that this offers further support for dual process theory of moral judgment. We also conclude that females tend to make less utilitarian personal moral decisions compared to males, providing further evidence that there are

  14. A Molecular Web: Endoplasmic Reticulum Stress, Inflammation and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Namrata eChaudhari

    2014-07-01

    Full Text Available Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded protein response (UPR through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS. Toxic accumulation of ROS within ER and mitochondria disturb fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways has been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease and others. In this review we have discussed the UPR signaling pathways, and networking between ER stress induced inflammatory pathways, oxidative stress and mitochondrial signaling events which further induce or exacerbate ER stress.

  15. Stress fractures and bone pain

    International Nuclear Information System (INIS)

    Groshar, D.; Even-Sapir, E.; Lam, M.; Israel, O.; Front, D.

    1984-01-01

    Stress fractures result from an unusual repetitive physical activity causing absorption of bone in excess of repair and bone formation. This leads to the weakening of the bone and subsequently to a fracture. It is a benign condition that if recognized in time does not need any treatment besides rest. However, if diagnosis is not made and physical activity continues it may result in severe injury to the bone and a frank fracture may result. Pain is the typical clinical feature and bone scintigraphy, being more sensitive than radiography, is done to establish early diagnosis. The presence of asymptomatic sites of abnormal bone uptake typical of stress fracture in which pain appeared only about 2 weeks after scintigraphy, drew the authors' attention to the question of how close is the relationship between stress fractures and bone pain. Sixty-four military recruits diagnosed as suffering from stress fracture were investigated in order to correlate sites with abnormal uptake of Tc-99m MDP on bone scintigraphy with sites of local pain. In 37 (58%) subjects multiple sites of abnormal uptake were recognised. Of 123 sites of abnormal uptake, 31 (25%) were asymptomatic. In three patients bone pain appeared at the site of the abnormal uptake two weeks after scintigraphy. Bone scintigraphy appears to be more sensitive than bone pain in the diagnosis of stress fractures. The osteoblastic activity which manifests itself by abnormal uptake appears in some cases earlier than the pain caused by the fracture. Present findings may suggest that under certain circumstances, in a population prone to stress fracture, bone scan should be considered as a screening method

  16. The influence of daily stress and resilience on successful ageing.

    Science.gov (United States)

    Byun, J; Jung, D

    2016-09-01

    The aim of this study was to identify the effects of daily stress and resilience on successful ageing among community-dwelling older adults. Ageing can be a positive experience if there is good adaptation to ageing processes. Positive ageing needs to be a basis of nursing care, health promotion and education within community settings. Data were collected in March and April of 2014 from 262 older adults living in Seoul and Jeju, South Korea. We used a four-part survey consisting of demographic data, daily stress, resilience and successful ageing scales, in total 91 items. Data were analysed using descriptive statistics, t-test, one-way ANOVA, Tukey HSD test, Pearson's correlation coefficient and hierarchical multiple regression analysis to identify the influence of variables on successful ageing. Successful ageing had a significant negative correlation with daily stress and a positive correlation with resilience. Daily stress had a negative correlation with resilience. Findings of hierarchical multiple regression analysis indicated that resilience and subjective economic status had an effect on successful ageing. Furthermore, these variables accounted for 41.6% of the variance in successful ageing. Data were collected in only two cities of Korea based on convenience sampling. The findings of the study suggest that daily stress and resilience have a statistically significant relationship with successful ageing. Furthermore, resilience is an important influential factor and a much-needed personal characteristic for one's successful ageing. Nurses can advocate joining with health and social policy makers to implement policies on healthy ageing, including evaluation of stress, education programmes and implementation of self-help groups to enhance resilience in older people. © 2016 International Council of Nurses.

  17. Stress Transmission and Failure in Disordered Porous Media

    Science.gov (United States)

    Laubie, Hadrien; Radjai, Farhang; Pellenq, Roland; Ulm, Franz-Josef

    2017-08-01

    By means of extensive lattice-element simulations, we investigate stress transmission and its relation with failure properties in increasingly disordered porous systems. We observe a non-Gaussian broadening of stress probability density functions under tensile loading with increasing porosity and disorder, revealing a gradual transition from a state governed by single-pore stress concentration to a state controlled by multipore interactions and metric disorder. This effect is captured by the excess kurtosis of stress distributions and shown to be nicely correlated with the second moment of local porosity fluctuations, which appears thus as a (dis)order parameter for the system. By generating statistical ensembles of porous textures with varying porosity and disorder, we derive a general expression for the fracture stress as a decreasing function of porosity and disorder. Focusing on critical sites where the local stress is above the global fracture threshold, we also analyze the transition to failure in terms of a coarse-graining length. These findings provide a general framework which can also be more generally applied to multiphase and structural heterogeneous materials.

  18. Perceived Stress Scale: Reliability and Validity Study in Greece

    Directory of Open Access Journals (Sweden)

    Eleni Andreou

    2011-08-01

    Full Text Available Objective: To translate the Perceived Stress Scale (versions PSS-4, -10 and -14 and to assess its psychometric properties in a sample of general Greek population. Methods: 941 individuals completed anonymously questionnaires comprising of PSS, the Depression Anxiety and Stress scale (DASS-21 version, and a list of stress-related symptoms. Psychometric properties of PSS were investigated by confirmatory factor analysis (construct validity, Cronbach’s alpha (reliability, and by investigating relations with the DASS-21 scores and the number of symptoms, across individuals’ characteristics. The two-factor structure of PSS-10 and PSS-14 was confirmed in our analysis. We found satisfactory Cronbach’s alpha values (0.82 for the full scale for PSS-14 and PSS-10 and marginal satisfactory values for PSS-4 (0.69. PSS score exhibited high correlation coefficients with DASS-21 subscales scores, meaning stress (r = 0.64, depression (r = 0.61, and anxiety (r = 0.54. Women reported significantly more stress compared to men and divorced or widows compared to married or singled only. A strong significant (p < 0.001 positive correlation between the stress score and the number of self-reported symptoms was also noted. Conclusions: The Greek versions of the PSS-14 and PSS-10 exhibited satisfactory psychometric properties and their use for research and health care practice is warranted.

  19. Examining the stress-burnout relationship: the mediating role of negative thoughts

    Directory of Open Access Journals (Sweden)

    Ko-Hsin Chang

    2017-12-01

    Full Text Available Background Using Smith’s (1986 cognitive-affective model of athletic burnout as a guiding framework, the purpose of this study was to examine the relationships among athletes’ stress in life, negative thoughts, and the mediating role of negative thoughts on the stress-burnout relationship. Methods A total of 300 college student-athletes (males = 174; females = 126, Mage = 20.43 y, SD = 1.68 completed the College Student Athlete’s Life Stress Scale (CSALSS; Lu et al., 2012, the Automatic Thoughts Questionnaire (ATQ; Hollon & Kendall, 1980, and the Athlete Burnout Questionnaire (ABQ; Raedeke & Smith, 2001. Results Correlational analyses found that two types of life stress and four types of negative thoughts correlated with burnout. Additionally, hierarchical regression analyses found that four types of negative thoughts partially mediated the stress-burnout relationship. Discussion We concluded that an athlete’s negative thoughts play a pivotal role in predicting athletes’ stress-burnout relationship. Future study may examine how irrational cognition influences athletes’ motivation and psychological well-being.

  20. Prediction of three-dimensional residual stresses at localised indentations in pipes

    International Nuclear Information System (INIS)

    Hyde, T.H.; Luo, R.; Becker, A.A.

    2012-01-01

    Residual stresses are investigated using Finite Element (FE) analyses at localised indentations in pipes with and without internal pressures due to reverse plasticity caused by springback of the surrounding material after removal of the indenter. The indentation loading is applied via rigid 3D short indenters. The effects of the residual indentation depth, internal pressure, indenter size and different material properties on the residual stresses for different pipes have been investigated by carrying out parametric sensitivity studies. In order to predict the residual stresses, empirical formulations have been developed, which show a good correlation with the FE for residual stresses for pipes with diameter to thickness ratios of 35–72. - Highlights: ► A comprehensive elastic–plastic FE analysis of residual stresses caused by localised pipe indentations is presented. ► The effects of residual indentation depth, internal pressure, indenter size and material properties have been studied. ► Empirical formulations have been developed, which show a good correlation with the FE for residual stresses for pipes with diameter to thickness ratios of 35–72.