40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level...

40 CFR 141.52 - Maximum contaminant level goals for microbiological contaminants.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant level goals for microbiological contaminants. 141.52 Section 141.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level...

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

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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.

Changing stress levels through gaining information on stress

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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.

Influence of Thread Root Radius on Maximum Local Stresses at Large Diameter Bolts under Axial Loading

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Cojocaru Vasile

2014-06-01

Full Text Available In the thread root area of the threaded bolts submitted to axial loading occur local stresses, higher that nominal stresses calculated for the bolts. These local stresses can generate failure and can reduce the fatigue life of the parts. The paper is focused on the study of the influence of the thread root radius on the maximum local stresses. A large diameter trapezoidal bolt was subjected to a static analysis (axial loading using finite element simulation.

Maximum penetration level of distributed generation without violating voltage limits

NARCIS (Netherlands)

Morren, J.; Haan, de S.W.H.

2009-01-01

Connection of Distributed Generation (DG) units to a distribution network will result in a local voltage increase. As there will be a maximum on the allowable voltage increase, this will limit the maximum allowable penetration level of DG. By reactive power compensation (by the DG unit itself) a

Three-level grid-connected photovoltaic inverter with maximum power point tracking

International Nuclear Information System (INIS)

Tsang, K.M.; Chan, W.L.

2013-01-01

Highlight: ► This paper reports a novel 3-level grid connected photovoltaic inverter. ► The inverter features maximum power point tracking and grid current shaping. ► The inverter can be acted as an active filter and a renewable power source. - Abstract: This paper presents a systematic way of designing control scheme for a grid-connected photovoltaic (PV) inverter featuring maximum power point tracking (MPPT) and grid current shaping. Unlike conventional design, only four power switches are required to achieve three output levels and it is not necessary to use any phase-locked-loop circuitry. For the proposed scheme, a simple integral controller has been designed for the tracking of the maximum power point of a PV array based on an improved extremum seeking control method. For the grid-connected inverter, a current loop controller and a voltage loop controller have been designed. The current loop controller is designed to shape the inverter output current while the voltage loop controller can maintain the capacitor voltage at a certain level and provide a reference inverter output current for the PV inverter without affecting the maximum power point of the PV array. Experimental results are included to demonstrate the effectiveness of the tracking and control scheme.

Pressurizer /Auxiliary Spray Piping Stress Analysis For Determination Of Lead Shielding Maximum Allow Able Load

International Nuclear Information System (INIS)

Setjo, Renaningsih

2000-01-01

Piping stress analysis for PZR/Auxiliary Spray Lines Nuclear Power Plant AV Unit I(PWR Type) has been carried out. The purpose of this analysis is to establish a maximum allowable load that is permitted at the time of need by placing lead shielding on the piping system on class 1 pipe, Pressurizer/Auxiliary Spray Lines (PZR/Aux.) Reactor Coolant Loop 1 and 4 for NPP AV Unit one in the mode 5 and 6 during outage. This analysis is intended to reduce the maximum amount of radiation dose for the operator during ISI ( In service Inspection) period.The result shown that the maximum allowable loads for 4 inches lines for PZR/Auxiliary Spray Lines is 123 lbs/feet

Fatigue life prediction method for contact wire using maximum local stress

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Seok; Haochuang, Li; Seok, Chang Sung; Koo, Jae Mean [Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Ki Won; Kwon, Sam Young; Cho, Yong Hyeon [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

2015-01-15

Railway contact wires supplying electricity to trains are exposed to repeated mechanical strain and stress caused by their own weight and discontinuous contact with a pantograph during train operation. Since the speed of railway transportation has increased continuously, railway industries have recently reported a number of contact wire failures caused by mechanical fatigue fractures instead of normal wear, which has been a more common failure mechanism. To secure the safety and durability of contact wires in environments with increased train speeds, a bending fatigue test on contact wire has been performed. The test equipment is too complicated to evaluate the fatigue characteristics of contact wire. Thus, the axial tension fatigue test was performed for a standard specimen, and the bending fatigue life for the contact wire structure was then predicted using the maximum local stress occurring at the top of the contact wire. Lastly, the tested bending fatigue life of the structure was compared with the fatigue life predicted by the axial tension fatigue test for verification.

Fatigue life prediction method for contact wire using maximum local stress

International Nuclear Information System (INIS)

Kim, Yong Seok; Haochuang, Li; Seok, Chang Sung; Koo, Jae Mean; Lee, Ki Won; Kwon, Sam Young; Cho, Yong Hyeon

2015-01-01

Railway contact wires supplying electricity to trains are exposed to repeated mechanical strain and stress caused by their own weight and discontinuous contact with a pantograph during train operation. Since the speed of railway transportation has increased continuously, railway industries have recently reported a number of contact wire failures caused by mechanical fatigue fractures instead of normal wear, which has been a more common failure mechanism. To secure the safety and durability of contact wires in environments with increased train speeds, a bending fatigue test on contact wire has been performed. The test equipment is too complicated to evaluate the fatigue characteristics of contact wire. Thus, the axial tension fatigue test was performed for a standard specimen, and the bending fatigue life for the contact wire structure was then predicted using the maximum local stress occurring at the top of the contact wire. Lastly, the tested bending fatigue life of the structure was compared with the fatigue life predicted by the axial tension fatigue test for verification.

Levels of occupational stress and stressful activities for nurses working in emergency

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José Ricardo Ferreira da Fonseca

2014-12-01

Full Text Available The study aimed to identify stress levels, areas and their activities identified as stressful by nurses working in the emergence in Manaus, AM, Brazil. It is an epidemiological, cross-sectional design, with 36 emergency nurses from December 2010 to January 2011. The Bianchi Stress Scale with 57 questions was used. The nurses were at risk for high levels of stress. The most stressful areas were the operation of the unit, conditions of work and personnel administration, and the most stressful activity was the request for equipment review and repair. The difference by Friedman test between the areas was significant (p <0.05, Dunn post-test significant (p <0.05 when compared by peers. The accumulation of management activities with the assistance activities can generate higher levels of stress, it is necessary to invest in improving the work environment and management support to minimize the stress experienced at work.

Numerical estimates of the maximum sustainable pore pressure in anticline formations using the tensor based concept of pore pressure-stress coupling

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Andreas Eckert

2015-02-01

Full Text Available The advanced tensor based concept of pore pressure-stress coupling is used to provide pre-injection analytical estimates of the maximum sustainable pore pressure change, ΔPc, for fluid injection scenarios into generic anticline geometries. The heterogeneous stress distribution for different prevailing stress regimes in combination with the Young's modulus (E contrast between the injection layer and the cap rock and the interbedding friction coefficient, μ, may result in large spatial and directional differences of ΔPc. A single value characterizing the cap rock as for horizontal layered injection scenarios is not obtained. It is observed that a higher Young's modulus in the cap rock and/or a weak mechanical coupling between layers amplifies the maximum and minimum ΔPc values in the valley and limb, respectively. These differences in ΔPc imposed by E and μ are further amplified by different stress regimes. The more compressional the stress regime is, the larger the differences between the maximum and minimum ΔPc values become. The results of this study show that, in general compressional stress regimes yield the largest magnitudes of ΔPc and extensional stress regimes provide the lowest values of ΔPc for anticline formations. Yet this conclusion has to be considered with care when folded anticline layers are characterized by flexural slip and the friction coefficient between layers is low, i.e. μ = 0.1. For such cases of weak mechanical coupling, ΔPc magnitudes may range from 0 MPa to 27 MPa, indicating imminent risk of fault reactivation in the cap rock.

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.

Detecting drawdowns masked by environmental stresses with water-level models

Science.gov (United States)

Garcia, C.A.; Halford, K.J.; Fenelon, J.M.

2013-01-01

Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations is presented and tested here. Drawdown is distinguished by analytically simulating all pumping and nonpumping water-level stresses simultaneously during the period of record. Pumping signals are generated with Theis models, where the pumping schedule is translated into water-level change with the Theis solution. This approach closely matched drawdowns simulated with a complex three-dimensional, hypothetical model and reasonably estimated drawdowns from an aquifer test conducted in a complex hydrogeologic system. Pumping-induced changes generated with a numerical model and analytical Theis model agreed (RMS as low as 0.007 m) in cases where pumping signals traveled more than 1 km across confining units and fault structures. Maximum drawdowns of about 0.05 m were analytically estimated from field investigations where environmental fluctuations approached 0.2 m during the analysis period.

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.

Stress Levels of Nurses in Oncology Outpatient Units.

Science.gov (United States)

Ko, Woonhwa; Kiser-Larson, Norma

2016-04-01

Oncology nursing is often a source of substantial stress for nurses. Many nurses, particularly novice nurses, have inadequate preparation to care for patients at the end of life and their families. Unless nurses prevent or manage work-related stress by using effective coping strategies, oncology nursing staff will continue to suffer from burnout and compassion fatigue. The purpose of this article is to identify stress levels and stressful factors of nurses working in oncology outpatient units and to explore coping behaviors for work-related stress of oncology staff nurses in outpatient units. A descriptive, cross-sectional design was used to identify stress levels and stressful factors for outpatient oncology nurses, investigate differences in stress levels among nurses' demographic characteristics, and explore coping behaviors of the nurses. Study participants (N = 40) included RNs and licensed practical nurses who completed the Nursing Stress Scale, three open-ended questions, and a demographic questionnaire. The highest sources of stress were workload and patient death and dying. Demographic variables of age and work experience in nursing showed a significant positive relationship to work-related stress scores. The three most frequently used coping behaviors were verbalizing, exercising or relaxing, and taking time for self. Continuing education programs on stress management are highly recommended. Outpatient oncology nurses should be nurtured and supported through tailored interventions at multiple levels to help them find effective coping strategies and develop self-care competencies. Although younger and less experienced nurses had lower mean stress scores than older and more experienced nurses, the continuing education programs and tailored interventions would be helpful for all oncology nursing staff.

Music class lower students' stress level

OpenAIRE

服部, 安里; 豊島, 久美子; 福井, 一

2015-01-01

This study has researched on psychological and steroid hormonal effect upon junior-high school students through school music lesson: 1. Music listening, 2. Choir singing. The result showed a significant decrease in cortisol. The study also had conducted a survey about participants' musical preference and their stress level (STAIC – II), which resulted that higher the stress level, more musical activity was willingly conducted. These outcomes suggest that school music lessons can lessen stude...

Plasma. beta. -endorphin and stress hormone levels during adaptation and stress

Energy Technology Data Exchange (ETDEWEB)

Lishmanov, Yu.B.; Trifonova, Zh.V.; Tsibin, A.N.; Maslova, L.V.; Dement' eva, L.A.

1987-09-01

This paper describes a comparative study of ..beta..-endorphin and stress hormone levels in the blood plasma of rats during stress and adaptation. Immunoreactive ..beta..-endorphin in the blood plasma was assayed by means of a kit after preliminary isolation of the ..beta..-endorphin fraction by affinity chromatography on sepharose; ACTH was assayed with a kit and cortisol, insulin, thyroxine and tri-iodothyronine by means of kits from Izotop. Determination of plasma levels of ..beta..-endorphin and other opioids could evidently be an important method of assessing the state of resistance of the organism to stress.

Stress Level and Adversity Quotient among Single Working Mothers

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Dianne Bautista Solis

2015-12-01

Full Text Available The study identified the profile of the single working mothers in terms of number of children, number of years as a single parent and reason for being a single parent; assessed the single mothers’ stress level and adversity quotient; determined the significant difference of stress level and adversity quotient of single mothers when grouped according to profile variables; determined the best predictor of stress level and adversity quotient. Moreover this research endeavoured to test significant relationship between the adversity quotient and stress level of single working mothers. Lastly, it proposed a stress management program for single working mothers for them to cope with their stress and adversities in life. The researcher employed quantitative method using standardized questionnaires namely Depression, Anxiety, Stress Scale (DASS and Adversity Response Profile (ARP. The respondents were twenty five (25 single working mothers of the students of Batangas State University. From the results, majority of the respondents have 3 children, widow and in early years as single parent; with a normal level of stress and an average adversity quotient.. There are no significant differences on the stress level and adversity quotient of the respondents when grouped according to profile variables. Finally, stress level has no significant effect on adversity quotient of single working mothers. From the findings, the researcher further recommends that the Office of Guidance and Counseling should update the student information database to determine students with a single working mother. The Parent-Teacher Association may form a single-parent subgroup for the single working mothers to be able to identify to other mothers with same situation. Moreover, the proposed stress management program may be reviewed and implemented by the Office of Guidance and Counseling in coordination with the Parent-Teacher Association of Batangas State University. Future researchers

Level of Work Related Stress among Teachers in Elementary Schools.

Science.gov (United States)

Agai-Demjaha, Teuta; Bislimovska, Jovanka Karadzinska; Mijakoski, Dragan

2015-09-15

Teaching is considered a highly stressful occupation, with work-related stress levels among teachers being among the highest compared to other professions. Unfortunately there are very few studies regarding the levels of work-related stress among teachers in the Republic of Macedonia. To identify the level of self-perceived work-related stress among teachers in elementary schools and its relationship to gender, age, position in the workplace, the level of education and working experience. We performed a descriptive-analytical model of a cross-sectional study that involved 300 teachers employed in nine elementary schools. Evaluation of examined subjects included completion of a specially designed questionnaire. We found that the majority of interviewed teachers perceive their work-related stress as moderate. The level of work-related stress was significantly high related to the gender, age, position in workplace, as well as working experience (p related to level of education (p stressful as compared to the upper-grade teachers (18.5% vs. 5.45%), while the same is true for female respondents as compared to the male ones (15.38% vs. 3.8%). In addition, our results show that teachers with university education significantly more often associate their workplace with stronger stress than their colleagues with high education (13.48% vs. 9.4%). We also found that there is no significant difference of stress levels between new and more experienced teachers. Our findings confirm that the majority of interviewed teachers perceived their work-related stress as high or very high. In terms of the relationship between the level of teachers' stress and certain demographic and job characteristics, according to our results, the level of work-related stress has shown significantly high relation to gender, age, levels of grades taught as well as working experience, and significant relation to the level of education.

The interplay of stress and sleep impacts BDNF level.

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Maria Giese

Full Text Available BACKGROUND: Sleep plays a pivotal role in normal biological functions. Sleep loss results in higher stress vulnerability and is often found in mental disorders. There is evidence that brain-derived neurotrophic factor (BDNF could be a central player in this relationship. Recently, we could demonstrate that subjects suffering from current symptoms of insomnia exhibited significantly decreased serum BDNF levels compared with sleep-healthy controls. In accordance with the paradigm indicating a link between sleep and BDNF, we aimed to investigate if the stress system influences the association between sleep and BDNF. METHODOLOGY/PRINCIPAL FINDINGS: Participants with current symptoms of insomnia plus a former diagnosis of Restless Legs Syndrome (RLS and/or Periodic Limb Movement (PLM and sleep healthy controls were included in the study. They completed questionnaires on sleep (ISI, Insomnia Severity Index and stress (PSS, Perceived Stress Scale and provided a blood sample for determination of serum BDNF. We found a significant interaction between stress and insomnia with an impact on serum BDNF levels. Moreover, insomnia severity groups and score on the PSS each revealed a significant main effect on serum BDNF levels. Insomnia severity was associated with increased stress experience affecting serum BDNF levels. Of note, the association between stress and BDNF was only observed in subjects without insomnia. Using a mediation model, sleep was revealed as a mediator of the association between stress experience and serum BDNF levels. CONCLUSIONS: This is the first study to show that the interplay between stress and sleep impacts BDNF levels, suggesting an important role of this relationship in the pathogenesis of stress-associated mental disorders. Hence, we suggest sleep as a key mediator at the connection between stress and BDNF. Whether sleep is maintained or disturbed might explain why some individuals are able to handle a certain stress load while

The interplay of stress and sleep impacts BDNF level.

Science.gov (United States)

Giese, Maria; Unternaehrer, Eva; Brand, Serge; Calabrese, Pasquale; Holsboer-Trachsler, Edith; Eckert, Anne

2013-01-01

Sleep plays a pivotal role in normal biological functions. Sleep loss results in higher stress vulnerability and is often found in mental disorders. There is evidence that brain-derived neurotrophic factor (BDNF) could be a central player in this relationship. Recently, we could demonstrate that subjects suffering from current symptoms of insomnia exhibited significantly decreased serum BDNF levels compared with sleep-healthy controls. In accordance with the paradigm indicating a link between sleep and BDNF, we aimed to investigate if the stress system influences the association between sleep and BDNF. Participants with current symptoms of insomnia plus a former diagnosis of Restless Legs Syndrome (RLS) and/or Periodic Limb Movement (PLM) and sleep healthy controls were included in the study. They completed questionnaires on sleep (ISI, Insomnia Severity Index) and stress (PSS, Perceived Stress Scale) and provided a blood sample for determination of serum BDNF. We found a significant interaction between stress and insomnia with an impact on serum BDNF levels. Moreover, insomnia severity groups and score on the PSS each revealed a significant main effect on serum BDNF levels. Insomnia severity was associated with increased stress experience affecting serum BDNF levels. Of note, the association between stress and BDNF was only observed in subjects without insomnia. Using a mediation model, sleep was revealed as a mediator of the association between stress experience and serum BDNF levels. This is the first study to show that the interplay between stress and sleep impacts BDNF levels, suggesting an important role of this relationship in the pathogenesis of stress-associated mental disorders. Hence, we suggest sleep as a key mediator at the connection between stress and BDNF. Whether sleep is maintained or disturbed might explain why some individuals are able to handle a certain stress load while others develop a mental disorder.

To reduce the maximum stress and the stress shielding effect around a dental implant-bone interface using radial functionally graded biomaterials.

Science.gov (United States)

Asgharzadeh Shirazi, H; Ayatollahi, M R; Asnafi, A

2017-05-01

In a dental implant system, the value of stress and its distribution plays a pivotal role on the strength, durability and life of the implant-bone system. A typical implant consists of a Titanium core and a thin layer of biocompatible material such as the hydroxyapatite. This coating has a wide range of clinical applications in orthopedics and dentistry due to its biocompatibility and bioactivity characteristics. Low bonding strength and sudden variation of mechanical properties between the coating and the metallic layers are the main disadvantages of such common implants. To overcome these problems, a radial distributed functionally graded biomaterial (FGBM) was proposed in this paper and the effect of material property on the stress distribution around the dental implant-bone interface was studied. A three-dimensional finite element simulation was used to illustrate how the use of radial FGBM dental implant can reduce the maximum von Mises stress and, also the stress shielding effect in both the cortical and cancellous bones. The results, of course, give anybody an idea about optimized behaviors that can be achieved using such materials. The finite element solver was validated by familiar methods and the results were compared to previous works in the literature.

25(OHD3 Levels Relative to Muscle Strength and Maximum Oxygen Uptake in Athletes

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Książek Anna

2016-04-01

Full Text Available Vitamin D is mainly known for its effects on the bone and calcium metabolism. The discovery of Vitamin D receptors in many extraskeletal cells suggests that it may also play a significant role in other organs and systems. The aim of our study was to assess the relationship between 25(OHD3 levels, lower limb isokinetic strength and maximum oxygen uptake in well-trained professional football players. We enrolled 43 Polish premier league soccer players. The mean age was 22.7±5.3 years. Our study showed decreased serum 25(OHD3 levels in 74.4% of the professional players. The results also demonstrated a lack of statistically significant correlation between 25(OHD3 levels and lower limb muscle strength with the exception of peak torque of the left knee extensors at an angular velocity of 150°/s (r=0.41. No significant correlations were found between hand grip strength and maximum oxygen uptake. Based on our study we concluded that in well-trained professional soccer players, there was no correlation between serum levels of 25(OHD3 and muscle strength or maximum oxygen uptake.

Does student debt affect dental students' and dentists' stress levels?

Science.gov (United States)

Boyles, J D; Ahmed, B

2017-10-27

Introduction Many studies have shown financial worries and debt to induce stress in individuals, this combined with the existing stress of being a dentist raises the question of how student debt affects students' and dentists' stress levels.Objectives Determine whether student debt has had any noticeable effect on student stress levels; investigate whether student debt has any effect on dentists' career choice; investigate whether the increase in tuition fees has influenced the number of applicants to study dentistry at the University of Birmingham.Method Anonymous questionnaires were completed by 70 4th year and 38 5th year BDS and 22 Dental Core Trainees (DCTs). Participants circled the response which best fitted their situation regarding statements on their level of stress and future career path. Ethical approval granted. Application figures to study dentistry obtained from head of admissions.Results Forty-two percent of males and 63% of females strongly agreed with the statement that having no debt would reduce their stress levels. Of those with debt >£40,000, 11% strongly agreed and 42% agreed that their total amount of student debt causes them stress. Whereas, those whose debt is stress. Seventy-seven percent of participants who had parental or family financial support reported this reduced their stress levels. Student debt was found to deter females from undertaking further study more than it deters males (P stressed about their total student loan(s) (P stress (P stress; students reporting a higher level of debt also report more stress and concern about paying off their student debt. Having no student debt would reduce stress levels, although to what extent is undetermined. Applications to study dentistry have fallen since the increase in tuition fees.

The Influence of Pressure Distribution on the Maximum Values of Stress in FEM Analysis of Plain Bearings

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Vasile Cojocaru

2016-12-01

Full Text Available Several methods can be used in the FEM studies to apply the loads on a plain bearing. The paper presents a comparative analysis of maximum stress obtained for three loading scenarios: resultant force applied on the shaft – bearing assembly, variable pressure with sinusoidal distribution applied on the bearing surface, variable pressure with parabolic distribution applied on the bearing surface.

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

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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

Vitamin K3 increased BMD at 1 and 2 months post-surgery and the maximum stress of the middle femur in the rat.

Science.gov (United States)

Hong, You-jia; Liu, Sheng; Jiang, Ning-yi; Jiang, Sen; Liang, Jiu-gen

2015-02-01

The therapeutic effects of vitamin K3 (VK3) on osteoporosis are still unknown. In this study, we hypothesized that VK3 possesses therapeutic effects on osteoporosis; to verify this hypothesis, the ovariectomized rat was used as an osteoporosis model. Fifty-six Sprague-Dawley female rats aged 8 to 9 months were randomly assigned to 4 groups: sham surgery, ovariectomy with saline, ovariectomy with low-dose VK3, and ovariectomy with high-dose VK3. Intramuscular injection of VK3 was performed every other day beginning 1 month postoperatively. The therapeutic effects of VK3 on osteoporosis were evaluated by measurement of bone mineral density (BMD), bone biochemical markers, biomechanical properties, and bone morphometric parameters. The overall average BMD in VK3-treated groups increased to a level between those of the ovariectomy group and the sham surgery group. The procollagen I N-terminal peptide level peaked at 2 months after surgery in all groups except in the group that had undergone ovariectomy with low-dose VK3. The tartrate-resistant acid phosphatase 5b level increased more slowly at 4 months after surgery than at 2 months after surgery in the VK3-treated groups. The ovariectomy with high-dose VK3 group had the highest maximum stress of the middle femur of all groups. With VK3 treatment, the trabecular bone area percentage increased. All morphometric indicators for the middle tibia in the VK3-treated groups reached the levels found in the sham surgery group. In summary, VK3 therapy increased BMD at 1 and 2 months postsurgery and the maximum stress of the middle femur. In addition, VK3 therapy slowed the increase in bone turnover in ovariectomized rats. Furthermore, VK3 can improve morphometric indicators for the middle tibia. Our preliminary study indicates that VK3 has a potential therapeutic effect on osteoporosis and is worthy of further investigation. Copyright © 2015 Elsevier Inc. All rights reserved.

An Iterative Maximum a Posteriori Estimation of Proficiency Level to Detect Multiple Local Likelihood Maxima

Science.gov (United States)

Magis, David; Raiche, Gilles

2010-01-01

In this article the authors focus on the issue of the nonuniqueness of the maximum likelihood (ML) estimator of proficiency level in item response theory (with special attention to logistic models). The usual maximum a posteriori (MAP) method offers a good alternative within that framework; however, this article highlights some drawbacks of its…

CHANGES IN SERUM ENZYMES LEVELS ASSOCIATED WITH LIVER FUNCTIONS IN STRESSED MARWARI GOAT

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Kataria N.

2011-03-01

Full Text Available Serum enzyme levels were determined in goats of Marwari breed belonging to farmers’ stock of arid tract of Rajasthan state, India. The animals were grouped into healthy and stressed comprising of gastrointestinal parasiticised, pneumonia affected, and drought affected. The serum enzymes determined were sorbitol dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, ornithine carbamoyl transferase, gamma-glutamayl transferase, 5’nucleotidase, glucose-6-phosphatase, arginase, and aldolase. In stressed group the mean values of all the enzymes increased significantly (p≤0.05 as compared to respective healthy mean value. All the enzymes showed highest values in the gastrointestinal parasiticised animals and least values in the animals having pneumonia. In gastrointestinal parasiticised animals maximum change was observed in G-6-Pase activity and minimum change was observed in malate dehydrogenase mean value. It was concluded that Increased activity of all the serum enzymes was due to modulation of liver functions directly or indirectly.

Level of Work Related Stress among Teachers in Elementary Schools

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Teuta Agai–Demjaha

2015-07-01

CONCLUSION: Our findings confirm that the majority of interviewed teachers perceived their work-related stress as high or very high. In terms of the relationship between the level of teachers’ stress and certain demographic and job characteristics, according to our results, the level of work-related stress has shown significantly high relation to gender, age, levels of grades taught as well as working experience, and significant relation to the level of education.

Multi-level restricted maximum likelihood covariance estimation and kriging for large non-gridded spatial datasets

KAUST Repository

Castrillon, Julio; Genton, Marc G.; Yokota, Rio

2015-01-01

We develop a multi-level restricted Gaussian maximum likelihood method for estimating the covariance function parameters and computing the best unbiased predictor. Our approach produces a new set of multi-level contrasts where the deterministic

Perceived stress at work is associated with lower levels of DHEA-S.

Science.gov (United States)

Lennartsson, Anna-Karin; Theorell, Töres; Rockwood, Alan L; Kushnir, Mark M; Jonsdottir, Ingibjörg H

2013-01-01

It is known that long-term psychosocial stress may cause or contribute to different diseases and symptoms and accelerate aging. One of the consequences of prolonged psychosocial stress may be a negative effect on the levels of dehydroepiandrosterone (DHEA) and its sulphated metabolite dehydroepiandrosterone sulphate (DHEA-S). The aim of this study is to investigate whether levels of DHEA and DHEA-S differ in individuals who report perceived stress at work compared to individuals who report no perceived stress at work. Morning fasting DHEA-S and DHEA levels were measured in serum in a non-stressed group (n = 40) and a stressed group (n = 41). DHEA and DHEA-S levels were compared between the groups using ANCOVA, controlling for age. The mean DHEA-S levels were 23% lower in the subjects who reported stress at work compared to the non-stressed group. Statistical analysis (ANCOVA) showed a significant difference in DHEA-S levels between the groups (p = 0.010). There was no difference in DHEA level between the groups. This study indicates that stressed individual have markedly lower levels of DHEA-S. Given the important and beneficial functions of DHEA and DHEA-S, lower levels of DHEA-S may constitute one link between psychosocial stress, ill health and accelerated ageing.

DETERMINATION OF ORGANIZATIONAL STRESS AND ORGANIZATIONAL BURNOUT LEVELS OF MID LEVEL MANAGERS WORKING IN FOUR AND FIVE STAR HOTEL BUSINESSES

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Sevket Yirik

2015-04-01

Full Text Available The present study emphasizes the concepts of stress and organizational stress which are the main concepts constituting theoretical foundation of the research; evaluates influences of stress on organization; discusses the concept of organizational burnout as well as its sub-dimensions; and analyses organizational stress and burnout levels of mid level managers working in four and five star hotels. The purpose of this study is to analyze the relationship between organizational stress and organizational burnout levels of mid level managers of four and five star hotel businesses. Survey has been conducted on 318 employees of four and five star hotels operating in Alanya, Turkey. According to the analysis of data, it has been observed that ages of mid level managers have an influence on their organizational stress and burnout levels. Genders of mid level managers are influential on their organizational stress levels while they have no influence on their burnout levels. Education levels of managers influence their organizational stress levels while they have no influence on their burnout levels. The departments of managers are influential both on organizational stress and burnout. Positions of managers influence their burnout levels while they have no influence on their organizational stress levels.

Stress level and academic performance of university students in ...

African Journals Online (AJOL)

This study examined the relationship between level of stress and students' academic performance in Universities in Kwara State, Nigeria. The study adopted a descriptive survey research design. Proportional stratified random sampling was used to select 300 students for the study. A “Students' Stress Level Questionnaire ...

Decreased Stress Levels in Nurses: A Benefit of Quiet Time.

Science.gov (United States)

Riemer, Heather C; Mates, Joanna; Ryan, Linda; Schleder, Bonnie J

2015-09-01

The benefits of quiet time, a therapeutic method of improving the health care environment, have been evaluated in patients, but only a few studies have examined the effects of quiet time on intensive care nurses. To evaluate the effects of implementing quiet time in a medical-surgical intensive care unit on levels of light, noise, and nurses' stress. Quiet time consisted of turning down the unit lights for a designated time. Levels of light, noise, and nurses' stress were measured. Nurses' stress levels were measured by using a 100-point visual analog scale; unit noise, by using a digital sound level meter (model 407736, Extech Instruments); and unit light, by using an illumination light meter (model 615, Huygen Corporation). Measurements were obtained 30 minutes before and 30 minutes, 1 hour, and 2 hours after implementation of quiet time. Analysis of variance and comparisons of means indicated that both light levels and nurses' stress levels were significantly decreased after quiet time (both P quiet time, but the decrease was not significant (P = .08). Use of quiet time resulted in decreased light levels and decreased stress levels among nurses. Quiet time is an easily performed energy-saving intervention to promote a healthy work environment. ©2015 American Association of Critical-Care Nurses.

Rigid MATLAB drivetrain model of a 500 kW wind turbine for predicting maximum gear tooth stresses in a planetary gearbox using multibody gear constraints

DEFF Research Database (Denmark)

Jørgensen, Martin Felix; Pedersen, Niels Leergaard; Sørensen, Jens Nørkær

2014-01-01

multiple planetary gears are not taken into account. Finite Element Method (FEM) calculations show that when the wind turbine runs close to the maximum wind speed, the maximum gear tooth stress is in the range of 500–700 MPa, which is considered to be realistic using a “worst-case” method. The presented...... for not only transferring torque but also for calculating the gear tooth and internal body reaction forces. The method is appropriate for predicting gear tooth stresses without considering all the complexity of gear tooth geometries. This means that, e.g. gear tooth load-sharing and load-distribution among...

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.

What Is Better Than Coulomb Failure Stress? A Ranking of Scalar Static Stress Triggering Mechanisms from 105 Mainshock-Aftershock Pairs

Science.gov (United States)

Meade, Brendan J.; DeVries, Phoebe M. R.; Faller, Jeremy; Viegas, Fernanda; Wattenberg, Martin

2017-11-01

Aftershocks may be triggered by the stresses generated by preceding mainshocks. The temporal frequency and maximum size of aftershocks are well described by the empirical Omori and Bath laws, but spatial patterns are more difficult to forecast. Coulomb failure stress is perhaps the most common criterion invoked to explain spatial distributions of aftershocks. Here we consider the spatial relationship between patterns of aftershocks and a comprehensive list of 38 static elastic scalar metrics of stress (including stress tensor invariants, maximum shear stress, and Coulomb failure stress) from 213 coseismic slip distributions worldwide. The rates of true-positive and false-positive classification of regions with and without aftershocks are assessed with receiver operating characteristic analysis. We infer that the stress metrics that are most consistent with observed aftershock locations are maximum shear stress and the magnitude of the second and third invariants of the stress tensor. These metrics are significantly better than random assignment at a significance level of 0.005 in over 80% of the slip distributions. In contrast, the widely used Coulomb failure stress criterion is distinguishable from random assignment in only 51-64% of the slip distributions. These results suggest that a number of alternative scalar metrics are better predictors of aftershock locations than classic Coulomb failure stress change.

Facility-level association of preoperative stress testing and postoperative adverse cardiac events.

Science.gov (United States)

Valle, Javier A; Graham, Laura; Thiruvoipati, Thejasvi; Grunwald, Gary; Armstrong, Ehrin J; Maddox, Thomas M; Hawn, Mary T; Bradley, Steven M

2018-06-22

Despite limited indications, preoperative stress testing is often used prior to non-cardiac surgery. Patient-level analyses of stress testing and outcomes are limited by case mix and selection bias. Therefore, we sought to describe facility-level rates of preoperative stress testing for non-cardiac surgery, and to determine the association between facility-level preoperative stress testing and postoperative major adverse cardiac events (MACE). We identified patients undergoing non-cardiac surgery within 2 years of percutaneous coronary intervention in the Veterans Affairs (VA) Health Care System, from 2004 to 2011, facility-level rates of preoperative stress testing and postoperative MACE (death, myocardial infarction (MI) or revascularisation within 30 days). We determined risk-standardised facility-level rates of stress testing and postoperative MACE, and the relationship between facility-level preoperative stress testing and postoperative MACE. Among 29 937 patients undergoing non-cardiac surgery at 131 VA facilities, the median facility rate of preoperative stress testing was 13.2% (IQR 9.7%-15.9%; range 6.0%-21.5%), and 30-day postoperative MACE was 4.0% (IQR 2.4%-5.4%). After risk standardisation, the median facility-level rate of stress testing was 12.7% (IQR 8.4%-17.4%) and postoperative MACE was 3.8% (IQR 2.3%-5.6%). There was no correlation between risk-standardised stress testing and composite MACE at the facility level (r=0.022, p=0.81), or with individual outcomes of death, MI or revascularisation. In a national cohort of veterans undergoing non-cardiac surgery, we observed substantial variation in facility-level rates of preoperative stress testing. Facilities with higher rates of preoperative stress testing were not associated with better postoperative outcomes. These findings suggest an opportunity to reduce variation in preoperative stress testing without sacrificing patient outcomes. © Article author(s) (or their employer(s) unless otherwise

Maximum surface level and temperature histories for Hanford waste tanks

International Nuclear Information System (INIS)

Flanagan, B.D.; Ha, N.D.; Huisingh, J.S.

1994-01-01

Radioactive defense waste resulting from the chemical processing of spent nuclear fuel has been accumulating at the Hanford Site since 1944. This waste is stored in underground waste-storage tanks. The Hanford Site Tank Farm Facilities Interim Safety Basis (ISB) provides a ready reference to the safety envelope for applicable tank farm facilities and installations. During preparation of the ISB, tank structural integrity concerns were identified as a key element in defining the safety envelope. These concerns, along with several deficiencies in the technical bases associated with the structural integrity issues and the corresponding operational limits/controls specified for conduct of normal tank farm operations are documented in the ISB. Consequently, a plan was initiated to upgrade the safety envelope technical bases by conducting Accelerated Safety Analyses-Phase 1 (ASA-Phase 1) sensitivity studies and additional structural evaluations. The purpose of this report is to facilitate the ASA-Phase 1 studies and future analyses of the single-shell tanks (SSTs) and double-shell tanks (DSTs) by compiling a quantitative summary of some of the past operating conditions the tanks have experienced during their existence. This report documents the available summaries of recorded maximum surface levels and maximum waste temperatures and references other sources for more specific data

The association between stress levels and food consumption among Iranian population.

Science.gov (United States)

Roohafza, Hamidreza; Sarrafzadegan, Nizal; Sadeghi, Masoumeh; Rafieian-Kopaei, Mahmoud; Sajjadi, Firouzeh; Khosravi-Boroujeni, Hossein

2013-03-01

Stress has been considered as a highly common disorder that has a complicated relation with dietary intake and has been linked with both increased and decreased dietary intake. This study was conducted to assess the association between food consumption and stress levels in an Iranian adult population. In this cross-sectional study, data from the third phase of Isfahan Healthy Heart Program (IHHP) that was conducted for cardiovascular diseases prevention and health promotion were used. Nine thousand five hundred forty-nine adults aged ≥ 18 years participated in the study. Dietary habits were assessed by a 49- item Food Frequency Questionnaire (FFQ). Stress levels were assessed by General Health Questionnaire-12 (GHQ-12). The participants were separated on the basis of their stress levels into two groups as the low- and high- stress groups.  Individuals in the low- stress group were significantly younger and tended to have higher physical activity and education level, lower LDL cholesterol, and were less likely to be current smokers. Dietary intake of unsaturated oils, grains, fruits, vegetables, meat, and dairy products was significantly higher in the low- stress group whereas dietary intake of saturated oils was significantly lower; moreover, Global Dietary Index (GDI) was lower in the low- stress group. We found a significant positive association between stress level, GDI (OR: 1.24; 95% CI: 1.14 - 1.35), and saturated oils (OR: 1.17; 95% CI: 1.08 - 1.28) and inverse association between stress level and intake of unsaturated oils (OR: 0.84 ; 95% CI: 0.77 - 0.91), fruits and vegetables (OR: 0.83; 95% CI: 0.76 - 0.90), meat (OR: 0.88; 95%CI: 0.82 - 0.97),and dairy products (OR: 0.88 ; 95% CI: 0.81 - 0.96) after adjustments based on sex, age, smoking, and physical activity. Our results showed a significant positive association between dietary intake and stress. We must have a special attention to dietary intake in stress management program of high- stress

EFFECT OF CAFFEINE ON OXIDATIVE STRESS DURING MAXIMUM INCREMENTAL EXERCISE

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Guillermo J. Olcina

2006-12-01

Full Text Available Caffeine (1,3,7-trimethylxanthine is an habitual substance present in a wide variety of beverages and in chocolate-based foods and it is also used as adjuvant in some drugs. The antioxidant ability of caffeine has been reported in contrast with its pro- oxidant effects derived from its action mechanism such as the systemic release of catecholamines. The aim of this work was to evaluate the effect of caffeine on exercise oxidative stress, measuring plasma vitamins A, E, C and malonaldehyde (MDA as markers of non enzymatic antioxidant status and lipid peroxidation respectively. Twenty young males participated in a double blind (caffeine 5mg·kg- 1 body weight or placebo cycling test until exhaustion. In the exercise test, where caffeine was ingested prior to the test, exercise time to exhaustion, maximum heart rate, and oxygen uptake significantly increased, whereas respiratory exchange ratio (RER decreased. Vitamins A and E decreased with exercise and vitamin C and MDA increased after both the caffeine and placebo tests but, regarding these particular variables, there were no significant differences between the two test conditions. The results obtained support the conclusion that this dose of caffeine enhances the ergospirometric response to cycling and has no effect on lipid peroxidation or on the antioxidant vitamins A, E and C

Influence of Diamondlike Carbon Coating of Screws on Axial Tightening Force and Stress Distribution on Overdenture Bar Frameworks with Different Fit Levels and Materials.

Science.gov (United States)

dos Santos, Mateus Bertolini Fernandes; Bacchi, Atais; Consani, Rafael Leonardo Xediek; Correr-Sobrinho, Lourenço

2015-01-01

The aim of this study was to evaluate the axial tightening force applied by conventional and diamondlike carbon (DLC)-coated screws and to verify, through three-dimensional finite element analysis (FEA), the stress distribution caused by different framework materials and prosthetic screws in overdenture frameworks with different misfit levels. The axial tightening force applied by the screw was evaluated by means of a titanium matrix connected to a load cell. Conventional titanium or DLC-coated screws were tightened with a digital torque wrench, and the load values were recorded. The values were applied in an FEA to a bar-clip attachment system connected to two 4.0 × 11-mm external-hexagon titanium implants placed in an anterior edentulous arch. DLC-coated and conventional screws were modeled with their respective axial forces obtained on the experimental evaluation for three bar framework materials (titanium, nickel-chromium, and cobalt-chromium) and three levels of misfit (100, 150, and 200 μm). Von Mises stresses for prosthetic components and maximum principal stress and microstrains (maximum principal strains) for bone tissue were measured. The mean force applied by the conventional screw was 25.55 N (± 1.78); the prosthetic screw coated with a DLC layer applied a mean force of 31.44 N (± 2.11), a statistically significant difference. In the FEA, the DLC screw led to higher stresses on the framework; however, the prosthetic screw suffered lower stress. No influence of screw type was seen in the bone tissue. Titanium frameworks reduced the stress transmitted to the bone tissue and the bar framework but had no influence on the screws. Higher misfit values resulted in an increased stress/strain in bone tissue and bar framework, which was not the case for retention screws.

Academic Stress Influences Periodontal Health Condition and Interleukin-1 beta Level

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Sandra O. Kuswandani

2014-10-01

Full Text Available Stress is a risk factor for periodontal disease, causing increase levels of interleukin-1 beta that involve in periodontal destruction. Objective: To analyze the relationship between academic stress in residency program students conditions and levels of interleukin-1 beta in gingival crevicular fluid. Methods: Thirty eight subjects filled the questionnaire of Graduate Dental Environtmental Stress (GDES, periodontal examination and samples of gingival crevicular fluid were tested for interleukin-1 beta with the Enzyme-linked Immunosorbent Assay (ELISA test. Results: There were significant differences between academic stress to periodontal tissue in oral hygiene (p=0.038, bleeding on probing index (p=0.02, but no significant differences in pocket depth and loss of attachment (p=0.972. There were significant differences between academic stress to levels of interleukin-1 beta (p=0.03, but no significant differences between levels of interleukin-1 beta to periodontal tissue in oral hygiene (p=0.465, bleeding on probing index (p=0.826, pocket depth (p=0.968, and loss of attachment (p=0.968. Conclusion: Academic stress influences the periodontal risk factor and level of interleukin-1 beta.

Relationship between stress levels and the status of serum ...

African Journals Online (AJOL)

Relationship between stress levels and the status of serum antioxidant vitamins. ... Abstract. Background: Alternative methods for stress monitoring and evaluation prove very useful in proper dealing with it. Thus ... from 32 Countries: Algeria (5) ...

Influence of irrigation water types and stress levels on cotton fibre and yarn quality for different varieties

International Nuclear Information System (INIS)

Nazar, A.; Ishaq, W.

2012-01-01

Cotton fibre quality is being deteriorated day by day due to various reasons and shortage/ poor quality of irrigation water is one of the reasons for the low quality of cotton fibre. The effect of the stress of water can be seen on the fibre length, strength and elongation. All these properties of fibre have also a significant influence on yarn characteristics and thus the yarn quality is also dependent on agronomic practices including irrigation. When new varieties are evolved it becomes necessary to examine such cotton varieties keenly, so that one which reflects maximum agricultural as well as industrial benefits can be recommended. The present study was planned to explore the spinning performance of various cotton varieties under different water quality treatments and water stress levels. Cotton of four varieties (CIM-501, CIM-496, CIM-499, and NIAB-111) under different types of irrigation water (canal water and tube well water) and different water stress levels (75ET, 100ET and 125ET) were selected for this research. The effect of these treatments was investigated on cotton fibre span length, strength and fibre elongation as well as on yarn quality. The study revealed that effect of different cotton varieties, water types and water stress levels on fibre and yarn quality was highly significant. Yarn characteristics showed greater values for the canal water similarly fibre length and elongations were better for canal water. Yarn tensile properties were decreased with increase in the water stress. The overall results indicated that the cotton variety NIAB-111 performed better as compared to other varieties. It is suggested that the cotton farmers may be trained by the agri. extension staff regarding maintenance of fibre quality through cultural practices and better irrigation techniques. (author)

Forced swimming stress does not affect monoamine levels and neurodegeneration in rats.

Science.gov (United States)

Abbas, Ghulam; Naqvi, Sabira; Mehmood, Shahab; Kabir, Nurul; Dar, Ahsana

2011-10-01

The current study was aimed to investigate the correlations between immobility time in the forced swimming test (FST, a behavioral indicator of stress level) and hippocampal monoamine levels (markers of depression), plasma adrenalin level (a peripheral marker of stress) as well as fluoro-jade C staining (a marker of neurodegeneration). Male Sprague-Dawley rats were subjected to acute, sub-chronic (7 d) or chronic (14 d) FSTs and immobility time was recorded. Levels of noradrenalin, serotonin and dopamine in the hippocampus, and adrenalin level in the plasma were quantified by high-performance liquid chromatography with electrochemical detection. Brain sections from rats after chronic forced swimming or rotenone treatment (3 mg/kg subcutaneously for 4 d) were stained with fluoro-jade C. The rats subjected to swimming stress (acute, sub-chronic and chronic) showed long immobility times [(214 +/- 5), (220 +/- 4) and (231 +/- 7) s, respectively], indicating that the animals were under stress. However, the rats did not exhibit significant declines in hippocampal monoamine levels, and the plasma adrenalin level was not significantly increased compared to that in unstressed rats. The rats that underwent chronic swimming stress did not manifest fluoro-jade C staining in brain sections, while degenerating neurons were evident after rotenone treatment. The immobility time in the FST does not correlate with markers of depression (monoamine levels) and internal stress (adrenalin levels and neurodegeneration), hence this parameter may not be a true indicator of stress level.

Evaluation of the levels of stress in the elderly living at home

Directory of Open Access Journals (Sweden)

Juliana Ladeira Garbaccio

2014-06-01

Full Text Available This study aimed at evaluating the stress level of the elderly assisted by the Primary Health Care of Piumhi, in the Midwest of Minas Gerais, Brazil, in 2010. This was a cross-sectional research with of 64 elderly residents in households. There was a predominance of older women. Regarding chronic diseases 81.3% were bearers of chronic diseases, 75% were cardiac and 29.7% had depression. In the Inventory of Symptoms of Stress for Adults, seniors kept the average 7 (low stress, being more frequent cognitive stress. Female gender was associated with stress level (p<0.05. The elderly showed a good physical and mental status, and we identified low levels of stress, predominantly the cognitive stress type.

Stress amongst middle level managers in schools

OpenAIRE

2014-01-01

M.Ed. (Psychology of Education) This research study originated from the belief that teachers in general, and secondary school teachers in particular, are under an inordinate amount of stress brought about largely as a result of their work as teachers and educators. Moving from that basic premise the research unfolded towards exploring at both theoretical and empirical level, the major causes and management of stress in education within a South African educational context. The study starts ...

Overall bolt stress optimization

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard

2013-01-01

The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

The relationship between the deep-level structure in crust and brewing of strong earthquakes in Xingtai area

Science.gov (United States)

Xiao, Lan-Xi; Zhu, Yuan-Qing; Zhang, Shao-Quan; Liu, Xu; Guo, Yu

1999-11-01

In this paper, crust medium is treated as Maxwell medium, and crust model includes hard inclusion, soft inclusion, deep-level fault. The stress concentration and its evolution with time are obtained by using three-dimensional finite element method and differential method. The conclusions are draw as follows: (1) The average stress concentration and maximum shear stress concentration caused by non-heterogeneous of crust are very high in hard inclusion and around the deep fault. With the time passing by, the concentration of average stress in the model gradually trends to uniform. At the same time, the concentration of maximum shear stress in hard inclusion increases gradually. This character is favorable to transfer shear strain energy from soft inclusion to hard inclusion. (2) When the upper mantle beneath the inclusion upheave at a certain velocity of 1 cm/a, the changes of average stress concentration with time become complex, and the boundary of the hard and soft inclusion become unconspicuous, but the maximum shear stress concentration increases much more in the hard inclusion with time at a higher velocity. This feature make for transformation of energy from the soft inclusion to the hard inclusion. (3) The changes of average stress concentration and maximum shear stress concentration with time around the deep-level fault result in further accumulation of maximum shear stress concentration and finally cause the deep-level fault instable and accelerated creep along fault direction. (4) The changes of vertical displacement on the surface of the model, which is caused by the accelerated creep of the deep-level fault, is similar to that of the observation data before Xingtai strong earthquake.

Preliminary analysis on the tectonic stress level in the source region of Tangshan earthquake

Science.gov (United States)

Jian-Tao, Zhao; Cui, Xiao-Feng; Xie, Fu-Ren

2002-05-01

The abundant data of focal mechanism solutions in Tangshan region, China, are inverted for the tectonic stress field. Combined with tectonophysical consideration, the magnitude of the three principal stresses, as well as their vertical variation under the average crustal rock property, in the source region of the 1976 Tangshan earthquake is estimated. The relationship between crustal stress and friction μ c, pore pressure P 0 and stress shape factor Φ is studied. The paper draws the conclusion that the vertical increasing rate of the maximum principal stress σ is directly proportional to friction, and inversely to pore pressure P 0 and stress shape factor Φ; while the vertical increasing rate of the minimum principal tress σ is directly proportional to pore pressure P 0, inversely to friction μ c and stress shape factor Φ. This study is a try to invert the data of focal mechanism solutions for the complete stress tensor.

Effect of sulfonylureas administered centrally on the blood glucose level in immobilization stress model.

Science.gov (United States)

Sharma, Naveen; Sim, Yun-Beom; Park, Soo-Hyun; Lim, Su-Min; Kim, Sung-Su; Jung, Jun-Sub; Hong, Jae-Seung; Suh, Hong-Won

2015-05-01

Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level.

Association between perceived stress, alcohol consumption levels and obesity in Koreans.

Science.gov (United States)

Yoon, Seung-Jin; Kim, Hae-Joon; Doo, Miae

2016-01-01

Coping with stress often leads to unhealthy behaviors that can have an impact on the development of obesity. Therefore, this study is investigate the effect of perceived stress level on alcohol consumption habits, as well as the effect of the interaction between alcohol consumption habits and stress level on obesity in Koreans. We analyzed perceived stress, alcohol consumption habits (alcohol consumption status, quantity, and alcohol use disorders identification test) and the anthropometrics of 6,229 subjects from the Korean National Health and Nutrition Examination Survey. The gender-based differences of the effect of the perceived level of stress on alcohol consumption habits and anthropometric measurements, as well as the interaction of the perceived level of stress and alcohol consumption habits on prevalence or ORs of obesity were analyzed. The subjects with high perceived stress showed higher proportions for unhealthy alcohol consumption habits than those with low perceived stress [ORs (95% CIs)=1.35 (1.19-1.54), 1.95 (1.68-2.26), and 1.87 (1.60-2.19) for alcohol consumption status, alcohol consumption quantity, and alcohol use disorders identification test, respectively]. Men showed significant interactions between the perceived stress and all alcohol consumption habits with respect to obesity [ORs (95% CIs)=1.28 (1.06-1.55), 1.81 (1.52-2.16), and 1.40 (1.17-1.68) for alcohol consumption status, alcohol consumption quantity, and alcohol use disorders identification test, respectively]. Among women, interactions between the perceived stress and alcohol consumption status [ORs (95% CIs)=0.70 (0.60-0.83)] and alcohol consumption quantity [ORs (95% CIs)=0.93 (0.54-1.36)] in relation to obesity were found to be significant. Our study demonstrated that the perceived stress influenced alcohol consumption habits that may have impacted obesity.

Development of a bionanodevice for detecting stress levels

International Nuclear Information System (INIS)

Nomura, S; Handri, S; Honda, H

2011-01-01

Recent advances in molecular analysis techniques have enabled scientists to assess the tiny amounts of biochemical substances secreted in our bodies. This has revealed that the levels of various secretory hormones and immune substances vary sensitively with the mental state of a person. Such hormones and immune substances exhibit transient increases with various psychological stressors. They thus have the potential to be used as a novel biometric for monitoring stress. Biomarkers that occur in saliva can be monitored non-invasively and are thus potentially useful as practical indicators of mental stress. Stress biomarkers are considered to be released into the blood stream or other secretory fluids by physiological stress reactions. Stress biomarkers are expected to be detectable in sweat and other humoral fluids that are exuded from the skin surface. Based on this, we have developed a bionanodevice for detecting stress by capturing stress biomarkers on the skin surface in a non-invasive manner. A prototype bionanodevice is described in which a motor protein is introduced for molecular handling.

Development of a bionanodevice for detecting stress levels

Energy Technology Data Exchange (ETDEWEB)

Nomura, S; Handri, S [Top Runner Incubation Center for Academia-Industry Fusion, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188 (Japan); Honda, H, E-mail: nomura@kjs.nagaokaut.ac.jp, E-mail: hhonda@vos.nagaokaut.ac.jp [Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188 (Japan)

2011-03-15

Recent advances in molecular analysis techniques have enabled scientists to assess the tiny amounts of biochemical substances secreted in our bodies. This has revealed that the levels of various secretory hormones and immune substances vary sensitively with the mental state of a person. Such hormones and immune substances exhibit transient increases with various psychological stressors. They thus have the potential to be used as a novel biometric for monitoring stress. Biomarkers that occur in saliva can be monitored non-invasively and are thus potentially useful as practical indicators of mental stress. Stress biomarkers are considered to be released into the blood stream or other secretory fluids by physiological stress reactions. Stress biomarkers are expected to be detectable in sweat and other humoral fluids that are exuded from the skin surface. Based on this, we have developed a bionanodevice for detecting stress by capturing stress biomarkers on the skin surface in a non-invasive manner. A prototype bionanodevice is described in which a motor protein is introduced for molecular handling.

Exercise-induced maximum metabolic rate scaled to body mass by ...

African Journals Online (AJOL)

Exercise-induced maximum metabolic rate scaled to body mass by the fractal ... rate scaling is that exercise-induced maximum aerobic metabolic rate (MMR) is ... muscle stress limitation, and maximized oxygen delivery and metabolic rates.

Effect of glacial-interglacial sea-level changes on the displacement and stress field in the forearc and along the plate interface of subduction zones

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T. Li

2012-02-01

Full Text Available Combined seismological, space-geodetic and numerical studies have shown that the seismicity at subduction zones may be modulated by tides and glacier fluctuations on timescales of 1–100 a, because these changes in loads on Earth's surface are able to alter the stress field in the upper plate and along the plate interface. Here we use a two-dimensional finite-element model of a subduction zone to investigate how glacial-interglacial sea-level changes affect the forearc region and the plate interface. The model results show that a sea-level fall by 125 m over 100 ka causes up to 0.7 m of vertical displacement, with the maximum uplift occurring between the trench and the coast. The uplift signal induced by the sea-level fall decreases to zero ~20 km landward of the coastline. A subsequent sea-level rise by 125 m over 20 ka causes subsidence, which is again most pronounced in the submarine part of the forearc. The sea-level changes cause horizontal displacements of up to 0.12 m, which are directed seaward during sea-level fall and landward during sea-level rise. With respect to the stress field, the sea-level changes lead to variations in the vertical stress and the shear stress of up to 1.23 MPa and 0.4 MPa, respectively. The shear stress variations are highest beneath the coast, i.e. in the area where the sea-level changes cause the strongest flexure. The resulting Coulomb stress changes on the plate interface are of the order of 0.2–0.5 MPa and indicate that earthquakes are promoted during sea-level fall and delayed during sea-level rise. Our findings imply that eustatic sea-level changes during glacial-interglacial periods may have induced displacements and stress changes that were large enough to affect the seismic cycle of subduction thrusts.

Coping With Stress of Teacher Trainees With Different Levels of Computer Anxiety

OpenAIRE

Ceyhan, Esra

2004-01-01

The aim of this study is to examine whether levels and styles of coping with the stress of teacher trainees having low and high levels of computer anxiety across a number of variables. This research was carried out with 800 teacher trainees. Data were collected using the Computer Anxiety Scale, Coping With Stress Scale, and an Information Form. The results of the study indicate that the computer anxiety levels of teacher trainees differentiate levels and styles of coping with stress. It was f...

Maximum Acceleration Recording Circuit

Science.gov (United States)

Bozeman, Richard J., Jr.

1995-01-01

Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

Estimation of fracture conditions of ceramics by thermal shock with laser beams based on the maximum compressive stress criterion

International Nuclear Information System (INIS)

Akiyama, Shigeru; Amada, Shigeyasu.

1992-01-01

Structural ceramics are attracting attention in the development of space planes, aircraft and nuclear fusion reactors because they have excellent wear-resistant and heat-resistant characteristics. However, in some applications it is anticipated that they will be exposed to very-high-temperature environments of the order of thousands of degrees. Therefore, it is very important to investigate their thermal shock characteristics. In this report, the distributions of temperatures and thermal stresses of cylindrically shaped ceramics under irradiation by laser beams are discussed using the finite-element computer code (MARC) with arbitrary quadrilateral axisymmetric ring elements. The relationships between spot diameters of laser beams and maximum values of compressive thermal stresses are derived for various power densities. From these relationships, a critical fracture curve is obtained, and it is compared with the experimental results. (author)

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

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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.

Cyclic fatigue of near-isotopic graphite: influence of stress cycle and neutron irradiation

International Nuclear Information System (INIS)

Price, R.J.

1977-11-01

Near-isotropic graphites H-451 and PGX were tested in uniaxial cyclic fatigue, and fatigue life (S-N) curves were generated to a maximum of 10 5 cycles. The stress ratio, R (minimum stress during a cycle divided by maximum stress) ranged from -1 to +0.5. With R = - 1, the homologous stress limits (maximum applied fatigue stress divided by the tensile strength) for 50% specimen survival to 10 5 cycles averaged 0.63 in the axial direction and 0.74 in the radial direction. Corresponding homologous stress limits for 99% specimen survival (99/95 tolerance limits) were 0.48 and 0.53. Higher R-values resulted in longer fatigue lives and increased stress limits. H-451 graphite specimens irradiated with fast neutrons at 1173 to 1263 0 K at fluences of up to 10 26 n/m 2 (equivalent fission fluence) showed fatigue stress limits of about twice the unirradiated levels when the unirradiated tensile strength was used as the basis for normalization

Using Conjugate Gradient Network to Classify Stress Level of Patients.

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Er. S. Pawar

2013-02-01

Full Text Available Diagnosis of stress is important because it can cause many diseases e.g., heart disease, headache, migraine, sleep problems, irritability etc. Diagnosis of stress in patients often involves acquisition of biological signals for example heart rate, electrocardiogram (ECG, electromyography signals (EMG etc. Stress diagnosis using biomedical signals is difficult and since the biomedical signals are too complex to generate any rule an experienced person or expert is needed to determine stress levels. Also, it is not feasible to use all the features that are available or possible to extract from the signal. So, relevant features should be chosen from the extracted features that are capable to diagnose stress. Electronics devices are increasingly being seen in the field of medicine for diagnosis, therapy, checking of stress levels etc. The research and development work of medical electronics engineers leads to the manufacturing of sophisticated diagnostic medical equipment needed to ensure good health care. Biomedical engineering combines the design and problem solving skills of engineering with medical and biological sciences to improve health care diagnosis and treatment.

Fracture criteria of reactor graphite under multiaxial stresses

International Nuclear Information System (INIS)

Sato, S.; Kawamata, K.; Kurumada, A.; Oku, T.

1987-01-01

New fracture criteria for graphite under multiaxial stresses are presented for designing core and support materials of a high temperature gas cooled reactor. Different kinds of fracture strength tests are carried out for a near isotropic graphite IG-11. Results show that, under the stress state in which tensile stresses are predominant, the maximum principal stress theory is seen as applicable for brittle fracture. Under the stress state in which compressive stresses are predominant there may be two fracture modes for brittle fracture, namely, slipping fracture and mode II fracture. For the former fracture mode the maximum shear stress criterion is suitable, but for the latter fracture mode a new mode II fracture criterion including a restraint effect for cracks is verified to be applicable. Also a statistical correction for brittle fracture criteria under multiaxial stresses is discussed. By considering the allowable stress values for safe design, the specified minimum ultimate strengths corresponding to a survival probability of 99% at the 95% confidence level are presented. (orig./HP)

Stress steroid levels and the short-term impact of routine dehorning ...

African Journals Online (AJOL)

Routine dehorning procedures resulted in a short-term stress response expressed by a significant increase in fGCM levels 48 h post-dehorning, with stress steroid levels returning to pre-dehorning concentrations 72 h after the procedure. Keywords: faecal glucocorticoid metabolites, non-invasive hormone monitoring, ...

Decreased total antioxidant levels and increased oxidative stress in ...

African Journals Online (AJOL)

Background: Chronic hyperglycaemia in diabetes mellitus leads to increased lipid peroxidation in the body, followed by the development of chronic complications due to oxidative stress. Objective: The aim of this study was to compare total antioxidant (TAO) levels and oxidative stress in type 2 diabetes mellitus (T2DM) ...

Maximum power point tracking techniques for wind energy systems using three levels boost converter

Science.gov (United States)

Tran, Cuong Hung; Nollet, Frédéric; Essounbouli, Najib; Hamzaoui, Abdelaziz

2018-05-01

This paper presents modeling and simulation of three level Boost DC-DC converter in Wind Energy Conversion System (WECS). Three-level Boost converter has significant advantage compared to conventional Boost. A maximum power point tracking (MPPT) method for a variable speed wind turbine using permanent magnet synchronous generator (PMSG) is also presented. Simulation of three-level Boost converter topology with Perturb and Observe algorithm and Fuzzy Logic Control is implemented in MATLAB/SIMULINK. Results of this simulation show that the system with MPPT using fuzzy logic controller has better performance to the Perturb and Observe algorithm: fast response under changing conditions and small oscillation.

Psychological stress in high level sailors during competition

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Luciana Segato

2010-09-01

Full Text Available The purpose of this work was to investigate the psychological stress present in elite sailors in a competition. Based on a descriptive field research, 31 elite sailors volunteered to participate. They answered the Perceived Stress Scale (Cohen & Williamson, 1988 and also specific questions on self-control, sources and strategies of coping. Data were analyzed by using descriptive and inferential (Student t test and Pearson's correlation statistics. These athletes revealed low and moderate scores (M = 20.00, DP = 6.83 of stress originated from both intrinsic (ship troubles, team disorders and extrinsic (study, working and training, family and financial problems sources. The group reported good stress control during competition through the use of cognitive (avoidance and somatic (listening music, resting/sleeping, talk to friends strategies. It is important that sailors are able to control and cope with high levels of psychological stress and to understand how to proceed when under unstable and unexpected situations that arise during competition.

Psychological stress in high level sailors during competition

Directory of Open Access Journals (Sweden)

L. Segato

2010-01-01

Full Text Available The purpose of this work was to investigate the psychological stress present in elite sailors in a competition. Based on a descriptive field research, 31 elite sailors volunteered to participate. They answered the Perceived Stress Scale (Cohen & Williamson, 1988 and also specific questions on self-control, sources and strategies of coping. Data were analyzed by using descriptive and inferential (Student t test and Pearson's correlation statistics. These athletes revealed low and moderate scores (M = 20.00, DP = 6.83 of stress originated from both intrinsic (ship troubles, team disorders and extrinsic (study, working and training, family and financial problems sources. The group reported good stress control during competition through the use of cognitive (avoidance and somatic (listening music, resting/sleeping, talk to friends strategies. It is important that sailors are able to control and cope with high levels of psychological stress and to understand how to proceed when under unstable and unexpected situations that arise during competition.

Comparative Stress Levels among Residents in Three Chinese Provincial Capitals, 2001 and 2008

Science.gov (United States)

Yang, Tingzhong; Wu, Dan; Zhang, Weifang; Cottrell, Randall R.; Rockett, Ian R. H.

2012-01-01

Objectives To compare stress levels among residents in large Chinese cities between 2001 and 2008. Methods Survey data were collected in three mainland Chinese capital cities in two waves, in 2001 and 2008, respectively. Participants were recruited through a multi-stage stratified sampling process. Stress was assessed using the Perceived Stress Scale, Chinese version (CPSS). Descriptive methods were used to estimate mean stress levels and associated 95% confidence intervals. Estimates were adjusted by post-stratification weights. Results Indicating stable stress levels, respective adjusted mean stress scores for the combined samples of study participants were 23.90 (95%CI: 23.68–24.12) in 2001 and 23.69 (95%CI: 23.38–24.01) in 2008. A lower stress level in 2008 than in 2001 manifested among residents who were under 25 years of age; female; with a college or higher level education; divorced, widowed, or separated; members of the managerial and clerical group; students or army personnel; or with an annual income of at least 30,000 RMB. Conclusion The overall stress level did not change among the combined sample of residents in the three Chinese study cities between 2001 and 2008. However, levels remained high and varied across social strata, and may have reflected a national trend among urban residents. Findings indicate a need for a new health policy, and call for the design and implementation of evidence-based interventions that target the highest-risk groups. PMID:23152832

Low-level lasers affect Escherichia coli cultures in hyperosmotic stress

Science.gov (United States)

Pinheiro, C. C.; Barboza, L. L.; Paoli, F.; Fonseca, A. S.

2015-08-01

Physical characteristics and practical properties have made lasers of interest for biomedical applications. Effects of low-level lasers on biological tissues could occur or be measurable depending on cell type, presence of a pathologic process or whether the cells are in an adverse environment. The objective of this work was to evaluate the survival, morphology and filamentation of E. coli cells proficient and deficient in the repair of oxidative DNA lesions exposed low-level red and infrared lasers submitted to hyperosmotic stress. Wild type and endonuclease VIII deficient E. coli cells in exponential and stationary growth phase were exposed to red and infrared lasers and submitted to hyperosmotic stress. Cell viability, filamentation phenotype and cell morphology were evaluated. Cell viability was not significantly altered but previous laser exposure induced filamentation and an altered area of stressed cells depending on physiologic condition and presence of the DNA repair. Results suggest that previous exposure to low-level red and infrared lasers could not affect viability but induced morphologic changes in cells submitted to hyperosmotic stress depending on physiologic conditions and repair of oxidative DNA lesions.

Protein intake and stress levels in nurses and housewives of Pakistan

Science.gov (United States)

Wattoo, Feroza Hamid; Memon, Muhammad Saleh; Memon, Allah Nawaz; Wattoo, Muhammad Hamid Sarwar; Asad, Muhammad Javaid; Siddique, Farzana

2011-01-01

Stress has many biological effects on human daily life. In the present study, dietary protein intake was correlated with the investigated stress levels of nurses and housewives of the targeted urban population. Age group ranged from 30 to 45 years and both the groups belonged to middle socioeconomic status. After calculations of environmental, psychological and physiological stresses, it was observed that the levels of stress in housewives were significantly higher than those of nurses. Recommended dietary allowances, RDA and actual protein intakes, API were also compared in both the groups. The found protein intake was less in housewives as compared to that of nurses. PMID:23961140

Stress, Anxiety and Depression Levels Among Elderly Referrals to Tehran Elderly Club

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Mohtasham Ghafari

2012-07-01

Full Text Available Objectives: Stress and anxiety have well–known effects in the pathogenesis of many physical and mental disorders. Aging adults are vulnerable to the effects of a negative stressor factors so, this study aims to investigate the level of stress anxiety and depression among the elderly referred to elderly clubs of Tehran in 2009. Methods & Materials: This is a cross-sectional study carried out on 104 aging adults, selected from elderly clubs of Tehran on 2009. Depression, Anxiety and Stress questionnaires (DASS-21, were filled out for this group. Finally obtained data was statistically analyzed by means of SPSS15 using T- test and One Way ANOVA at the significant level P≤0.05. Results: Of the total subjects under study 24% were male, and 76% female, with a mean age of 63.37±4.32 and 65.08±4.82 years respectively. The proportion of women with high anxiety score was higher than men. There were also higher anxiety levels in illness people (P<0.001. Conclusion: This study on depression, anxiety and stress as an indicator of lifestyle reveals high stress levels in the elderly population, which warrants appropriate planning and community-based interventions, to improve lifestyle and reduce stress level in aging adults.

Behavior of deep level defects on voltage-induced stress of Cu(In,Ga)Se{sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Lee, D.W.; Cho, S.E. [Department of Physics and Semiconductor Science, Dongguk University, Seoul (Korea, Republic of); Jeong, J.H. [Solar Cell Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Cho, H.Y., E-mail: hycho@dongguk.edu [Department of Physics and Semiconductor Science, Dongguk University, Seoul (Korea, Republic of)

2015-05-01

The behavior of deep level defects by a voltage-induced stress for CuInGaSe{sub 2} (CIGS) solar cells has been investigated. CIGS solar cells were used with standard structures which are Al-doped ZnO/i-ZnO/CdS/CIGSe{sub 2}/Mo on soda lime glass, and that resulted in conversion efficiencies as high as 16%. The samples with the same structure were isothermally stressed at 100 °C under the reverse voltages. The voltage-induced stressing in CIGS samples causes a decrease in the carrier density and conversion efficiency. To investigate the behavior of deep level defects in the stressed CIGS cells, photo-induced current transient spectroscopy was utilized, and normally 3 deep level defects (including 2 hole traps and 1 electron trap) were found to be located at 0.18 eV and 0.29 eV above the valence band maximum (and 0.36 eV below the conduction band). In voltage-induced cells, especially, it was found that the decrease of the hole carrier density could be responsible for the increase of the 0.29 eV defect, which is known to be observed in less efficient CIGS solar cells. And the carrier density and the defects are reversible at least to a large extent by resting at room-temperature without the bias voltage. From optical capture kinetics in photo-induced current transient spectroscopy measurement, the types of defects could be distinguished into the isolated point defect and the extended defect. In this work, it is suggested that the increase of the 0.29 eV defect by voltage-induced stress could be due to electrical activation accompanied by a loss of positive ion species and the activated defect gives rise to reduction of the carrier density. - Highlights: • We investigated behavior of deep level defects by voltage-induced stress. • Defect generation could affect the decrease of the conversion efficiency of cells. • Defect generation could be electrically activated by a loss of positive ion species. • Type of defects could be studied with models of point defects

RAGE polymorphisms and oxidative stress levels in Hashimoto's thyroiditis.

Science.gov (United States)

Giannakou, Maria; Saltiki, Katerina; Mantzou, Emily; Loukari, Eleni; Philippou, Georgios; Terzidis, Konstantinos; Lili, Kiriaki; Stavrianos, Charalampos; Kyprianou, Miltiades; Alevizaki, Maria

2017-05-01

Polymorphisms of the receptor for advanced glycation end products (RAGE) gene have been studied in various autoimmune disorders, but not in Hashimoto's thyroiditis. Also, increased oxidative stress has been described in patients with Hashimoto's thyroiditis. The aim of this study was to investigate the possible role of two common RAGE polymorphisms (-429T>C, -374T>A) in Hashimoto's thyroiditis; in parallel, we studied oxidative stress levels. A total of 300 consecutive euthyroid women were examined and classified into three groups: Hashimoto's thyroiditis with treatment (n = 96), Hashimoto's thyroiditis without treatment (n = 109) and controls (n = 95). For a rough evaluation of oxidative stress, total lipid peroxide levels in serum were measured. The -429T>C AluI and -374T>A MfeI polymorphisms of RAGE were studied in genomic DNA. Significant association of the RAGE system with Hashimoto's thyroiditis was found only with regard to the prevalence of the -429T>C, but not with -374T>A polymorphism. The levels of oxidative stress were significantly elevated in Hashimoto's thyroiditis patients under treatment. Further analysis demonstrated that an oxidative stress cut-off value of 590 μmol/L is associated with an increased risk of progression of Hashimoto's thyroiditis from euthyroidism to hypothyroidism; this risk is further increased in carriers of the RAGE -429T>C polymorphism. Our findings indicate that both examined risk factors may be implicated in the occurrence of Hashimoto's thyroiditis, but this covers only a fraction of the pathophysiology of the disease. © 2017 Stichting European Society for Clinical Investigation Journal Foundation.

Stability numerical analysis of soil cave in karst area to drawdown of underground water level

Science.gov (United States)

Mo, Yizheng; Xiao, Rencheng; Deng, Zongwei

2018-05-01

With the underground water level falling, the reliable estimates of the stability and deformation characteristics of soil caves in karst region area are required for analysis used for engineering design. Aimed at this goal, combined with practical engineering and field geotechnical test, detail analysis on vertical maximum displacement of top, vertical maximum displacement of surface, maximum principal stress and maximum shear stress were conducted by finite element software, with an emphasis on two varying factors: the size and the depth of soil cave. The calculations on the soil cave show that, its stability of soil cave is affected by both the size and depth, and only when extending a certain limit, the collapse occurred along with the falling of underground water; Additionally, its maximum shear stress is in arch toes, and its deformation curve trend of maximum displacement is similar to the maximum shear stress, which further verified that the collapse of soil cave was mainly due to shear-failure.

An event- and network-level analysis of college students' maximum drinking day.

Science.gov (United States)

Meisel, Matthew K; DiBello, Angelo M; Balestrieri, Sara G; Ott, Miles Q; DiGuiseppi, Graham T; Clark, Melissa A; Barnett, Nancy P

2018-04-01

Heavy episodic drinking is common among college students and remains a serious public health issue. Previous event-level research among college students has examined behaviors and individual-level characteristics that drive consumption and related consequences but often ignores the social network of people with whom these heavy drinking episodes occur. The main aim of the current study was to investigate the network of social connections between drinkers on their heaviest drinking occasions. Sociocentric network methods were used to collect information from individuals in the first-year class (N=1342) at one university. Past-month drinkers (N=972) reported on the characteristics of their heaviest drinking occasion in the past month and indicated who else among their network connections was present during this occasion. Average max drinking day indegree, or the total number of times a participant was nominated as being present on another students' heaviest drinking occasion, was 2.50 (SD=2.05). Network autocorrelation models indicated that max drinking day indegree (e.g., popularity on heaviest drinking occassions) and peers' number of drinks on their own maximum drinking occasions were significantly associated with participant maximum number of drinks, after controlling for demographic variables, pregaming, and global network indegree (e.g., popularity in the entire first-year class). Being present at other peers' heaviest drinking occasions is associated with greater drinking quantities on one's own heaviest drinking occasion. These findings suggest the potential for interventions that target peer influences within close social networks of drinkers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Stress-Response Psycho-Training on the Stress Levels of Mothers with Autistic Children

Science.gov (United States)

Karaman, Ömer

2018-01-01

The aim of the study was to assess the effect of stress-response psycho-training on the stress levels of mothers with autistic children. The research was experimental in design encompassing a pretest-posttest model with control and placebo groups. Participation in the study was voluntary with a total of 28 mothers of autistic children included…

High altitude induced anorexia: effect of changes in leptin and oxidative stress levels.

Science.gov (United States)

Vats, Praveen; Singh, Vijay Kumar; Singh, Som Nath; Singh, Shashi Bala

2007-01-01

High altitude (HA) exposure usually leads to a significant weight loss in non-acclimatized humans. Anorexia is believed to be the main cause of this body weight loss. Appetite regulatory peptides, i.e. leptin and neuropeptide Y play a key role in food intake and energy homeostasis. Recent studies suggests increased oxidative stress during HA exposure. In present study effect of HA exposure on levels of leptin and NPY was evaluated along with N-acetyl cysteine (NAC) and vitamin E supplementation in relation to food intake and body weight changes. The study was conducted on 30 healthy male volunteers (age 19-29 years). Subjects were divided randomly into three groups of 10 each. Group 1 (placebo) supplemented with 400 mg of calcium gluconate, group 2 and 3 were supplemented with 400 mg of NAC and 400 mg vitamin E, respectively per day. The study was conducted at low altitude (320 m, Phase I), at HA 3600 m (Phase II) and at an altitude of 4580 m (Phase III). On HA exposure significant reduction in plasma leptin levels was observed in all the groups on day 2 (Phase II) along with decrease in food intake and reduction in body weight. Statistically significant increase in blood malondialdehyde (MDA) levels was seen in all the groups on HA exposure (Phase II, Day 2), but the maximum increase was in case of placebo group (65.1%) on day 2 (Phase II) in comparison to low altitude values. The decrease in energy intake was almost same in all the groups indicating that antioxidant supplementation did not provide any protection against HA anorexia. From the study, it may be concluded that leptin and oxidative stress possibly are not the key players for HA anorexia.

Effect of stress on serum lipid levels in lady health visitors and housewives

International Nuclear Information System (INIS)

Wattoo, F.H.; Memon, M.S.; Memon, A.N.; Wattoo, M.H.S.; Tirmizi, S.A.; Iqbal, J.

2007-01-01

To study the effects of stress among lady health visitors and housewives in regard to their serum total cholesterol, HDL cholesterol, and LDL cholesterol and triglyceride levels. The study was performed at the Institute of Biochemistry, University of Sindh, Jamshoro, Pakistan during the years 2003 to 2005. Seventy lady health visitor and housewives aged between 25-40 years participated in this study and were selected from Hyderabad and its adjoining areas. Environmental, psychological and physiological stress levels were measured with likert scale. Total cholesterol, LDL cholesterol and HDL cholesterol and triglyceride levels were measured. Environmental, psychological and physiological stresses were significantly higher in housewives as compared to lady health visitors. A low level of HDL cholesterol was observed in housewives as compared to lady health visitors. The levels of total cholesterol, LDL cholesterol and triglyceride were found higher in housewives than lady health visitors. Housewives are under more stress than lady health visitors. The levels of total cholesterol, LDL cholesterol and triglyceride increases but HDL cholesterol decrease with stress. (author)

Effectiveness of stress release geometries on reducing residual stress in electroforming metal microstructure

Science.gov (United States)

Song, Chang; Du, Liqun; Zhao, Wenjun; Zhu, Heqing; Zhao, Wen; Wang, Weitai

2018-04-01

Micro electroforming, as a mature micromachining technology, is widely used to fabricate metal microdevices in micro electro mechanical systems (MEMS). However, large residual stress in the local positions of the micro electroforming layer often leads to non-uniform residual stress distributions, dimension accuracy defects and reliability issues during fabrication of the metal microdevice. To solve this problem, a novel design method of presetting stress release geometries in the topological structure of the metal microstructure is proposed in this paper. First, the effect of stress release geometries (circular shape, annular groove shape and rivet shape) on the residual stress in the metal microstructure was investigated by finite element modeling (FEM) analysis. Two evaluation parameters, stress concentration factor K T and stress non-uniformity factor δ were calculated. The simulation results show that presetting stress release geometries can effectively reduce and homogenize the residual stress in the metal microstructures were measured metal microstructure. By combined use with stress release geometries of annular groove shape and rivet shape, the stress concentration factor K T and the stress non-uniformity factor δ both decreased at a maximum of 49% and 53%, respectively. Meanwhile, the average residual stress σ avg decreased at a maximum of 20% from  -292.4 MPa to  -232.6 MPa. Then, micro electroforming experiments were carried out corresponding to the simulation models. The residual stresses in the metal microstructures were measured by micro Raman spectroscopy (MRS) method. The results of the experiment proved that the stress non-uniformity factor δ and the average residual stress σ avg also decreased at a maximum with the combination use of annular groove shape and rivet shape stress release geometries, which is in agreement with the results of FEM analysis. The stress non-uniformity factor δ has a maximum decrease of 49% and the

High intensity and reduced volume training attenuates stress and recovery levels in elite swimmers

DEFF Research Database (Denmark)

Elbe, Anne-Marie; Rasmussen, Camilla P; Nielsen, Glen

2016-01-01

This study investigated the effect of increased high-intensity interval training (HIT) at the expense of total training volume on the stress and recovery levels of elite swimmers. Forty-one elite swimmers participated in the study and were randomly assigned to either a HIT or a control group (CON....... The Recovery Stress Questionnaire - Sport was used to measure the swimmers' stress and recovery levels. After the 12 week intervention, the general stress level was 16.6% (2.6-30.7%; mean and 95% CI) lower and the general recovery level was 6.5% (0.7-12.4%) higher in HIT compared to the CON, after adjusting...... for baseline values. No significant effects could be observed in sports-specific stress or sports-specific recovery. The results indicate that increasing training intensity and reducing training volume for 12 weeks can reduce general stress and increase general recovery levels in competitive swimmers....

Effect of blood glucose level on acute stress response of grass carp Ctenopharyngodon idella.

Science.gov (United States)

Jiang, Danli; Wu, Yubo; Huang, Di; Ren, Xing; Wang, Yan

2017-10-01

Stress has a considerable impact on welfare and productivity of fish, and blood glucose level of fish may be a factor modulating stress response. This study evaluated the effect of blood glucose level and handling on acute stress response of grass carp Ctenopharyngodon idella. Fish were intraperitoneally injected with glucose at 0, 0.2, 0.5, and 1.0 mg g -1 body mass (BM) and then were exposed to handling for 5 min. Glucose injection resulted in increase of plasma glucose level and liver glycogen content and decrease of plasma lactate level. Handling resulted in increase of plasma levels of cortisol, glucose, and lactate and plasma lactic dehydrogenase (LDH) activity and decrease of liver glycogen content. At 1 h post-stress, the plasma cortisol level was lower in the stressed fish injected with glucose at 0.5 mg g -1 BM than the stressed fish injected with glucose at 0, 0.2, and 1.0 mg g -1 BM. No significant differences were found in the activities of phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate kinase (PK) in the liver between the stressed and unstressed fish, regardless of the dose of glucose injection. At 1 h post-stress, the liver glucose-6-phosphatase (G6Pase) activity was higher in the fish without glucose injection than in the fish injected with glucose. This study reveals that blood glucose level can affect stress response of grass carp by modulating cortisol release and glucose homeostasis through glycogen metabolism and gluconeogenesis in the liver.

A Quantitative Examination Whether Education Mitigates Stress Levels among Law Enforcement Officers

Science.gov (United States)

Metts, Gary A.

2012-01-01

Stress is damaging if it is continual, overwhelming. and prolonged. Law enforcement officers face stressful events daily. A relationship exists between stress levels and the physical and psychological effects to the human body. Although there is a general understanding of the damage stress can do physically and psychologically, many elements that…

Lithium modulates the chronic stress-induced effect on blood glucose level of male rats

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Popović Nataša

2010-01-01

Full Text Available In the present study we examined gross changes in the mass of whole adrenal glands and that of the adrenal cortex, as well as the serum corticosterone and glucose level of mature male Wistar rats subjected to three different treatments: animals subjected to chronic restraint-stress, animals injected with lithium (Li and chronically stressed rats treated with Li. Under all three conditions we observed hypertrophy of whole adrenals, as well as the adrenal cortices. Chronic restraint stress, solely or in combination with Li treatment, significantly elevated the corticosterone level, but did not change the blood glucose level. Animals treated only with Li exhibited an elevated serum corticosterone level and blood glucose level. The aim of our study was to investigate the modulation of the chronic stress-induced effect on the blood glucose level by lithium, as a possible mechanism of avoiding the damage caused by chronic stress. Our results showed that lithium is an agent of choice which may help to reduce stress-elevated corticosterone and replenish exhausted glucose storages in an organism.

Stress in ion-implanted CVD Si3N4 films

International Nuclear Information System (INIS)

EerNisse, E.P.

1977-01-01

The compressive stress buildup caused in chemical-vapor-deposited (CVD) Si 3 N 4 films by ion implantation is shown to be caused entirely by atomic collision effects, ionization effects being unimportant. The stress introduction rate is shown to be independent of CVD processing variables and O content of the film. The maximum attainable compressive stress change is 3.5 x 10 10 dyn/cm 2 , resulting in a maximum net compressive stress of 2 x 10 10 dyn/cm 2 for films on Si where the as-deposited films inherently have 1.5 x 10 10 dyn/cm 2 tensile stress before ion implantation. Results are presented which show that O in the films inhibits thermal annealing of the ion-implantation-induced compressive stress. Results for introduction rate and annealing effects are presented in normalized form so that workers can use the effects for intentional stress level adjustment in the films to reduce probability of cracking and detachment

Critical water stress levels in Pinus patula seedlings and their ...

African Journals Online (AJOL)

Critical water stress levels in Pinus patula seedlings and their relation to measures of seedling morphology. ... Southern Forests: a Journal of Forest Science ... A pot trial was implemented to determine the effect of soil water stress following transplanting on shoot water potential and stomatal conductance of Pinus patula ...

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...

Effect of year of study on stress levels in male undergraduate dental students

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Alzahem AM

2013-10-01

Full Text Available Abdullah M Alzahem,1 Henk T van der Molen,2 Benjamin J de Boer31Advanced Education in General Dentistry (AEGD Residency Program, King Abdullah International Medical Research Center/King Saud bin Abdulaziz University for Health Sciences/National Guard Health Affairs, Riyadh, Saudi Arabia; 2Institute of Psychology, Faculty of Social Sciences, Erasmus University, Rotterdam, The Netherlands; 3Clinical Psychology, Princess Nora University, Riyadh, Saudi ArabiaObjective: Stress among dental students can be a significant threat, resulting in physical and/or mental illness, and have a negative effect on students' performance and the professional practice of dentistry. Stress can occur from different sources. The purpose of this study is to test whether the year of study has an effect on the stress levels of dental students.Method: Our study consisted of a cross-sectional survey using a modified version of the Dental Environment Stress (DES questionnaire. The questionnaires were filled out by male undergraduate dental students at King Saud University in Riyadh City during the 2010–2011 academic year (n = 214.Results: The results show the most common sources of stress: examinations and completing clinical requirements. Moreover, in the five-year lecture-based traditional curriculum, the third year students reported the highest level of stress, whereas the first year reported the lowest level of stress.Conclusion: Third year undergraduate dental students reported the highest level of stress. This stress could be reduced by reviewing and modifying the dental curriculum by allowing students to have contact with patients more gradually, starting from the first year, in addition to adding stress prevention and intervention programs in dental curricula.Keywords: dental, education, students, stress, study year

Oxidative stress reduces levels of dysbindin-1A via its PEST domain.

Science.gov (United States)

Yap, Mei-Yi Alicia; Lo, Yew-Long; Talbot, Konrad; Ong, Wei-Yi

2014-12-01

Oxidative stress resulting from the generation of reactive oxygen species has been proposed as an etiological factor in schizophrenia. The present study tests the hypothesis that oxidative stress can affect levels of dysbindin-1A, encoded by Dtnbp1, a genetic risk factor for schizophrenia, via its PEST domain. In vitro studies on SH-SY5Y cells indicate that oxidative stress triggers proteasomal degradation of dysbindin-1A, and that this requires interactions with its PEST domain, which may be a TRIM32 target. We specifically found (a) that oxidative stress induced in SH-SY5Y cells by 500 µM hydrogen peroxide reduced levels of full-length dysbindin-1, but did not reduce levels of that protein lacking its PEST domain and (b) that levels of full-length dysbindin-1, but not dysbindin-1 lacking its PEST domain, were higher in cells treated with the proteasome inhibitor MG132. Oxidative stress thus emerges as the first known cellular factor regulating dysbindin-1 isoforms with PEST domains. These findings are consistent with the previously noted fact that phosphorylation of PEST domains often marks proteins for proteasomal degradation, and raises the possibility that treatments reducing oxidative stress in the brain, especially during development, may lower schizophrenia risk. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stress in childhood, adolescence and early adulthood, and cortisol levels in older age.

Science.gov (United States)

Harris, Mathew A; Cox, Simon R; Brett, Caroline E; Deary, Ian J; MacLullich, Alasdair M J

2017-03-01

The glucocorticoid hypothesis suggests that overexposure to stress may cause permanent upregulation of cortisol. Stress in youth may therefore influence cortisol levels even in older age. Using data from the 6-Day Sample, we investigated the effects of high stress in childhood, adolescence and early adulthood - as well as individual variables contributing to these measures; parental loss, social deprivation, school and home moves, illness, divorce and job instability - upon cortisol levels at age 77 years. Waking, waking +45 min (peak) and evening salivary cortisol samples were collected from 159 participants, and the 150 who were not using steroid medications were included in this study. After correcting for multiple comparisons, the only significant association was between early-adulthood job instability and later-life peak cortisol levels. After excluding participants with dementia or possible mild cognitive impairment, early-adulthood high stress showed significant associations with lower evening and mean cortisol levels, suggesting downregulation by stress, but these results did not survive correction for multiple comparisons. Overall, our results do not provide strong evidence of a relationship between stress in youth and later-life cortisol levels, but do suggest that some more long-term stressors, such as job instability, may indeed produce lasting upregulation of cortisol, persisting into the mid-to-late seventies.

Military experience and levels of stress and coping in police officers.

Science.gov (United States)

Hartley, Tara A; Violanti, John M; Mnatsakanova, Anna; Andrew, Michael E; Burchfiel, Cecil M

2013-01-01

Policing is a stressful occupation and working in this environment may make officers more vulnerable to adverse psychological and physiological outcomes. The impact of prior military experience on work stress and coping strategies has not been well-studied in police. The purpose of this cross-sectional study was to examine differences in levels of police-related stress and coping in officers with and without military experience. Participants were 452 police officers from the Buffalo Cardio-metabolic Occupational Police Stress Study Officers were categorized into three groups: non-military (n = 334), non-combat military (n = 84), and military with combat (n = 34). Age, sex and education adjusted levels of psychological stress and coping measures were compared across the three groups using ANCOVA. P-values were derived from post-hoc comparisons. Non-military police officers had significantly higher stress levels for physically and psychological threatening events compared to non-combat officers (p = 0.019). Non-military officers also reported experiencing significantly more organizational stressors and physically and psychologically threatening events in the past year than combat and non-combat officers (p military officers (p = 0.010, p = 0.005, respectively). In summary, police officers without military experience reported experiencing more organizational and life-threatening events than officers who served in the military. Yet combat officers were less likely to utilize positive coping than non-combat and non-military officers. These findings demonstrate the potential positive influence of military experience on police stress. Further research is needed as military veterans return to police work.

Effect of stress on serum cholestrol levels in nurses and housewives of Hyderabad - Pakistan

International Nuclear Information System (INIS)

Watto, F.H.; Memon, M.S.; Memon, A.N.; Ghanghro, A.B.; Yaquib, M.; Watto, M.H.S.; Tirmizi, S.A.

2010-01-01

A cohort type study was designed to evaluate environmental, psychological and physiological stresses in nurses and housewives and to correlate with their serum total cholesterol, HDL cholesterol, LDL cholesterol and triglyceride levels. Total 160 females from middle socioeconomic groups (nurses, n=80 and housewives, n=80) aged between 25-45 years participated in this study and subjects were selected from Hyderabad and its adjoining areas. Environmental, psychological and physiological stress levels were measured with likert scale. Total cholesterol, LDL cholesterol and HDL cholesterol were measured by CHOD-PAP method and triglyceride levels were measured by GPO method. Housewives were found to have high levels of total cholesterol, LDL cholesterol and triglycerides. The HDL cholesterol were lower. Environmental, psychological and physiological stresses were significantly higher in housewives as compared to the nurses. Highest level of environmental stress was observed in nonworking group i.e. housewives. A significant relation between serum cholesterol levels and three types of stresses was observed. (author)

CLASSICAL MUSIC DECREASE STRESS LEVEL AND BLOOD PRESSURE PRIMIGRAVIDA IN THE THIRD TRIMESTER

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Ni Ketut Alit Armini

2017-07-01

Full Text Available Introduction: Many changes in psychology and biology increase primigravida’s stress in the third trimester. The stress response makes blood pressure being unstable, it causes bad effect for pregnancy. Classical music can be used as one of relaxation facilities that can reduce stress. The aimed of this study were to analyze the effect of classical music on stress level and blood pressure. Method: This study was used a quasy experimental purposive sampling design. The sample in this study were 14 pregnancy women in the third trimester in RSIA Cempaka Putih Permata Surabaya. The independent variable in this study was classical music and the dependent variable were stress level and blood pressure. Data were analyzed by Wilcoxon Signed Rank Test, Mann Withney U Test, Paired t Test and Independent t Test with significance level α≤0.05. Result: The result showed that the stress level in controlled group with p=0.567 and intervention group with p=0.025. The result of blood pressure in controlled group with p=0.522 in systolic blood pressure, p=0.35 in diastolic blood pressure and intervention group showed p=0.103 in systolic blood pressure and p=1.00 in diastolic blood pressure. Discussion: It can be concluded that listening classical music can reduce stress level, stabilize blood pressure, although blood pressure hasn’t significant result but mean of blood pressure show that it was stable. Further studies should be considered to used cortisol to identify stress biology response spesifically.

Evaluating Heavy Metal Stress Levels in Rice Based on Remote Sensing Phenology.

Science.gov (United States)

Liu, Tianjiao; Liu, Xiangnan; Liu, Meiling; Wu, Ling

2018-03-14

Heavy metal pollution of croplands is a major environmental problem worldwide. Methods for accurately and quickly monitoring heavy metal stress have important practical significance. Many studies have explored heavy metal stress in rice in relation to physiological function or physiological factors, but few studies have considered phenology, which can be sensitive to heavy metal stress. In this study, we used an integrated Normalized Difference Vegetation Index (NDVI) time-series image set to extract remote sensing phenology. A phenological indicator relatively sensitive to heavy metal stress was chosen from the obtained phenological periods and phenological parameters. The Dry Weight of Roots (WRT), which directly affected by heavy metal stress, was simulated by the World Food Study (WOFOST) model; then, a feature space based on the phenological indicator and WRT was established for monitoring heavy metal stress. The results indicated that the feature space can distinguish the heavy metal stress levels in rice, with accuracy greater than 95% for distinguishing the severe stress level. This finding provides scientific evidence for combining rice phenology and physiological characteristics in time and space, and the method is useful to monitor heavy metal stress in rice.

The association of personality traits and coping styles according to stress level

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Hamid Afshar

2015-01-01

Full Text Available Background: Some personality traits and coping styles could be as risk factors in stressful situations. This study aimed to investigate the association of personality traits and coping styles according to the stress level. Meterials and Methods: This cross-sectional study was performed in 2011. A total of 4628 individuals over 20 years were selected by random sampling from nonacademic employees that working in 50 different centers across Isfahan province. Data were collected using 12-item General Health Questionnaire (GHQ-12, Big Five Personality Inventory Short Form and coping strategies scale, and individuals were divided into high and low-stress groups in term of GHQ-12. To analyze the data, a binary logistic regression analysis was conducted. Results: Mean age of participants was 36.3 ± 7.91 years and 56.26% (2604 of them were female. Neuroticism with adjusting covariates of demographic characteristics and the rest of personality traits was a risk factor for stress level with odds ratios (OR OR:1.24; but other personality traits were protective. Also, active coping styles were protective factors for OR of stress level with adjusting covariates of demographic characteristics and the rest of coping styles, and positive reinterpretation and growth was the most effective of coping style with OR:0.84. Conclusion: Some personality traits are associated with passive copings and cause high-stress level. So, it could be concluded that improve and strengthen effective coping strategies in individual with maladaptive traits should be considered as a crucial component of prevention and control programs of stress.

Acute stress induces hyperacusis in women with high levels of emotional exhaustion.

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Dan Hasson

Full Text Available BACKGROUND: Hearing problems is one of the top ten public health disorders in the general population and there is a well-established relationship between stress and hearing problems. The aim of the present study was to explore if an acute stress will increase auditory sensitivity (hyperacusis in individuals with high levels of emotional exhaustion (EE. METHODS: Hyperacusis was assessed using uncomfortable loudness levels (ULL in 348 individuals (140 men; 208 women; age 23-71 years. Multivariate analyses (ordered logistic regression, were used to calculate odds ratios, including interacting or confounding effects of age, gender, ear wax and hearing loss (PTA. Two-way ANCOVAs were used to assess possible differences in mean ULLs between EE groups pre- and post-acute stress task (a combination of cold pressor, emotional Stroop and Social stress/video recording. RESULTS: There were no baseline differences in mean ULLs between the three EE groups (one-way ANOVA. However, after the acute stress exposure there were significant differences in ULL means between the EE-groups in women. Post-hoc analyses showed that the differences in mean ULLs were between those with high vs. low EE (range 5.5-6.5 dB. Similar results were found for frequencies 0.5 and 1 kHz. The results demonstrate that women with high EE-levels display hyperacusis after an acute stress task. The odds of having hyperacusis were 2.5 (2 kHz, right ear; left ns and 2.2 (4 kHz, right ear; left ns times higher among those with high EE compared to those with low levels. All these results are adjusted for age, hearing loss and ear wax. CONCLUSION: Women with high levels of emotional exhaustion become more sensitive to sound after an acute stress task. This novel finding highlights the importance of including emotional exhaustion in the diagnosis and treatment of hearing problems.

Acute stress induces hyperacusis in women with high levels of emotional exhaustion.

Science.gov (United States)

Hasson, Dan; Theorell, Töres; Bergquist, Jonas; Canlon, Barbara

2013-01-01

Hearing problems is one of the top ten public health disorders in the general population and there is a well-established relationship between stress and hearing problems. The aim of the present study was to explore if an acute stress will increase auditory sensitivity (hyperacusis) in individuals with high levels of emotional exhaustion (EE). Hyperacusis was assessed using uncomfortable loudness levels (ULL) in 348 individuals (140 men; 208 women; age 23-71 years). Multivariate analyses (ordered logistic regression), were used to calculate odds ratios, including interacting or confounding effects of age, gender, ear wax and hearing loss (PTA). Two-way ANCOVAs were used to assess possible differences in mean ULLs between EE groups pre- and post-acute stress task (a combination of cold pressor, emotional Stroop and Social stress/video recording). There were no baseline differences in mean ULLs between the three EE groups (one-way ANOVA). However, after the acute stress exposure there were significant differences in ULL means between the EE-groups in women. Post-hoc analyses showed that the differences in mean ULLs were between those with high vs. low EE (range 5.5-6.5 dB). Similar results were found for frequencies 0.5 and 1 kHz. The results demonstrate that women with high EE-levels display hyperacusis after an acute stress task. The odds of having hyperacusis were 2.5 (2 kHz, right ear; left ns) and 2.2 (4 kHz, right ear; left ns) times higher among those with high EE compared to those with low levels. All these results are adjusted for age, hearing loss and ear wax. Women with high levels of emotional exhaustion become more sensitive to sound after an acute stress task. This novel finding highlights the importance of including emotional exhaustion in the diagnosis and treatment of hearing problems.

Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods

International Nuclear Information System (INIS)

Chady, T.

2004-01-01

In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials' properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by scanning the surface of the specimens with GMR gradiometer. Next, the same samples were evaluated using an eddy current sensor. A comparison between results obtained from both methods was carried out. Finally, selected parameters of the measured signal were calculated and utilized to evaluate level of the applied stress. A strong coincidence between amount of the applied stress and the maximum amplitude of the derivative was confirmed

Association between Inflammatory Potential of Diet and Stress Levels in Adolescent Women in Iran.

Science.gov (United States)

Shivappa, Nitin; Hebert, James R; Rashidkhani, Bahram

2017-02-01

The relation between diet and stress has not been widely explored. In this study, we examined the association between the inflammatory potential of diet and levels of stress among adolescent girls in Iran. A total of 299 adolescent girls aged 15-18 years were recruited during 2014-2015. Stress was assessed using the Depression, Anxiety and Stress Scale (DASS)-21 scale. Data were analyzed as continuous DASS scores and as a dichotomous outcome with a cut-off value of 9. The dietary inflammatory index (DII) is a literature-derived population-based dietary. DII scores were index computed from dietary intake assessed using a validated food frequency questionnaire. Multivariable linear and logistic regressions were used to calculate beta estimates and odds ratios adjusting for potential confounding factors. In total, 84 girls (28% of the entire study sample) had at least a moderate level of stress symptoms (DASS > 9). Girls with the most pro-inflammatory diet (tertile 3) had higher DASS stress scores (β = 2.75; 95% CI = 1.05, 4.46) and were at 3.48 times (95% CI = 1.33, 9.09) risk of having at least moderate level of stress compared to girls with the most anti-inflammatory diets (tertile 1). These data suggest that Iranian adolescent girls with a pro-inflammatory diet, as shown by higher DII scores, had higher levels of stress and greater odds of having at least a moderate level of stress symptoms.

The effects of acute foot shock stress on empathy levels in rats.

Science.gov (United States)

Karakilic, Aslı; Kizildag, Servet; Kandis, Sevim; Guvendi, Guven; Koc, Basar; Camsari, Gamze B; Camsari, Ulas M; Ates, Mehmet; Arda, Sevil Gonenc; Uysal, Nazan

2018-09-03

Empathy defined as the ability to understand and the share the feelings, thoughts, and attitudes of another, is an important skill in survival and reproduction. Among many factors that affect empathy include psychological stress, anxiety states. The aim of this study was to investigate the impact of acute psychological stress on empathic behavior and its association with oxytocin and vasopressin levels in amygdala and prefrontal cortex. Rats were subjected to 0.2 mA (low) and 1.6 mA (high) intensity of foot shock stress for duration of 20 min. Empathic behavior was found to be improved as a response to low intensity stress, but not to high intensity stress. As a response to lower intensity stress, vasopressin was increased in prefrontal cortex and amygdala; oxytocin was increased in only prefrontal cortex, and corticosterone levels increased in general. Anxiety indicators did not change in low intensity stress group yet; high intensity stress group demonstrated a lesser degree of anxiety response. High intensity stress group stayed unexpectedly more active in middle area of elevated plus maze test equipment, which may support impaired executive decision making abilities in the setting of high anxiety states. Further research is needed to investigate gender effects, the role of dopaminergic system and other stress related pathways in acute stress. Copyright © 2018 Elsevier B.V. All rights reserved.

Multi-level restricted maximum likelihood covariance estimation and kriging for large non-gridded spatial datasets

KAUST Repository

Castrillon, Julio

2015-11-10

We develop a multi-level restricted Gaussian maximum likelihood method for estimating the covariance function parameters and computing the best unbiased predictor. Our approach produces a new set of multi-level contrasts where the deterministic parameters of the model are filtered out thus enabling the estimation of the covariance parameters to be decoupled from the deterministic component. Moreover, the multi-level covariance matrix of the contrasts exhibit fast decay that is dependent on the smoothness of the covariance function. Due to the fast decay of the multi-level covariance matrix coefficients only a small set is computed with a level dependent criterion. We demonstrate our approach on problems of up to 512,000 observations with a Matérn covariance function and highly irregular placements of the observations. In addition, these problems are numerically unstable and hard to solve with traditional methods.

Stress level among intensive care nurses in the municipality of Paraná (Brazil

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Kelly Cristina Inoue

2014-04-01

Full Text Available Objective. To identify stress levels among intensive care nurses who work in the municipality of Western Paraná, Brazil. Methodology. This is a cross-sectional cohort study, carried out from May to July 2010, included 60 nurses from intensive care units (adult, pediatric, or neonatal of five hospitals. All participants completed the Bianchi Stress Scale. Results. The mean participant age was 31 years; 70% of the nurses were women, 33% had more than 15 years of experience, and 88% conducted care activities. The general level of stress was medium. Stress levels were low for relationships with other units and supervisors, activities related to adequate functioning of the unit and the coordination of activities of the unit. Levels were medium for the following domains: activities related to personnel management, labor conditions for the development of nursing activities, and delivery of care to patient; this last domain was related to the following stress factors: facing patient death, attending to emergencies in the unit, advising patients' family members, and conducting tasks in the minimal time available. Conclusion. Although the general stress level was medium, the identification of domains with a high score can be used to plan intervention strategies to preserve the health of intensive care nurses and, in turn, improve quality of care delivered to severely ill patients.

Couple-level Minority Stress: An Examination of Same-sex Couples' Unique Experiences.

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Frost, David M; LeBlanc, Allen J; de Vries, Brian; Alston-Stepnitz, Eli; Stephenson, Rob; Woodyatt, Cory

2017-12-01

Social stress resulting from stigma, prejudice, and discrimination-"minority stress"-negatively impacts sexual minority individuals' health and relational well-being. The present study examined how being in a same-sex couple can result in exposure to unique minority stressors not accounted for at the individual level. Relationship timeline interviews were conducted with 120 same-sex couples equally distributed across two study sites (Atlanta and San Francisco), gender (male and female), and relationship duration (at least six months but less than three years, at least three years but less than seven years, and seven or more years). Directed content analyses identified 17 unique couple-level minority stressors experienced within nine distinct social contexts. Analyses also revealed experiences of dyadic minority stress processes (stress discrepancies and stress contagion). These findings can be useful in future efforts to better understand and address the cumulative impact of minority stress on relational well-being and individual health.

WORK STRESS LEVEL AND CARING BEHAVIOUR OF NURSES

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Retno Lestari

2017-04-01

Full Text Available Introduction: A nurse who experience burnout feelings will influence their motivation, and quality performance. This situation is probably affecting a decline in work quality towards the caring behaviour demonstrated by nurses to their patiens, particularly for a nurse who are working in the long-stay installation room facing directly to patient's problems. The purpose of this research is to identify the work stress level of nurse towards the nurse's caring behaviour in the long-stay installation room (IRNA in general hospital in Malang. Method: This research used descriptive – correlational, the sampling was Non Probability Purposive Sampling with 93 nurses as the corresponds. The data was analyzed by operating Correlation Pearson, with a significance of p < 0.05. Result: The result found that there was a substantial correlation between the work stress level and the nurse's caring behaviour with p = 0.008 and r = -0.274, and it was a negative correlation. Discussion: It means that when the stress level of nurses will declined, the nurse's caring behavior automatically will beamplified. Conversely, if the stess level of nurses intensively increased, the nurse's caring behaviour become decreased. Thus, this research is needed to be analyzed further in order to asses the quality of caring behaviour by expanding the connected indicator and variable. It is aimed to improve the professionalism and quality of nurses in giving the best service to patients this research need to be continued further in order to asses the quality of nurse's caring behavior by expanding the variable, which is related to internal factors, such as knowledge, perception, emotion, ect and also connected to external factors, such as environment, both physically and non physically like: climate, human being, social economic, culture and ect.

Stress, depression, quality of life and salivary cortisol levels in community health agents.

Science.gov (United States)

Knuth, Berenice Scaletzky; Cocco, Rafaela Abreu; Radtke, Vinicius Augusto; Medeiros, João Ricardo Carvalho; Oses, Jean Pierre; Wiener, Carolina David; Jansen, Karen

2016-06-01

To determine the prevalence of and factors associated with depression and stress with perceived quality of life and the salivary cortisol levels in Community Health Agent (CHA). Materials and Methods Cross-sectional descriptive study of CHAs in Pelotas-RS, Brazil. Data collection, including sociodemographic information and factors related to work and health. Beck Depression Inventory (BDI) II was used to assess depressive symptoms, Inventory of Stress Symptoms Lipp (ISSL) was used for the analysis of stress and the WHOQOL-BREF was used to investigate quality of life. Salivary cortisol was quantified via ELISA test. The assessments showed that 71.0% are in a state of stress resistance, 30.5% were in the alert state of stress and 32.8% were in the stress state of exhaustion. Depressive episodes (BDI≥12) were observed in 28.2%. The environmental domain had the lowest score for quality of life. We observed significantly higher salivary cortisol levels in CHAs with less than 1 year of service and with the lowest quality of life scores in the environmental subsection. A high prevalence of stress and depression was observed in this sample of CHAs. In addition, the worst levels of quality of life were identified in the environmental subsection. Cortisol levels corroborate these findings regarding quality of life within the environmental domain and began working less than a year previously.

Influence of mechanical stress level in preliminary stress-corrosion testing on fatigue strength of a low-carbon steel

International Nuclear Information System (INIS)

Aleskerova, S.A.; Pakharyan, V.A.

1978-01-01

Effect of corrosion and mechanical factors of preliminary stress corrosion of a metal in its fatigue strength, has been investigated. Smooth cylindrical samples of 20 steel have been tested. Preliminary corrosion under stress has been carried out under natural sea conditions. It is shown that mechanical stresses in the case of preliminary corrosion affect fatigue strength of low-carbon steels, decreasing the range of limited durability and fatigue limit. This effect increases with the increase of stress level and agressivity of corrosive medium

The Influence of Time Management Practices on Job Stress Level among Beginning Secondary Agriculture Teachers

Science.gov (United States)

Lambert, Misty D.; Torres, Robert M.; Tummons, John D.

2012-01-01

Monitoring the stress of teachers continues to be important--particularly stress levels of beginning agriculture teachers. The study sought to describe the relationship between beginning teachers' perceived ability to manage their time and their level of stress. The Time Management Practices Inventory and the Job Stress Survey were used to measure…

STRESS LEVEL AND SMOKING STATUS IN CENTRAL IRAN: ISFAHAN HEALTHY HEART PROGRAM

Directory of Open Access Journals (Sweden)

Hamidreza Roohafza

2011-04-01

Full Text Available BACKGROUND: Individuals are faced with numerous stressful life events which can negatively influence mental health. Many individuals use smoking as a means of confronting stress. Given the relatively high prevalence of smoking in central Iran, the present study was conducted to compare stress levels in smokers, non-smokers and those who had quit smoking.    METHODS: This study was conducted as part of Isfahan Cardiovascular Research Program on 9752 individuals in the cities of Isfahan, Arak, and Najafabad in 2008. Sampling was performed using multi-stage cluster randomization method. Data on age, sex, demographic characteristics, and smoking status was collected through interviews. Stress level detected by General Health questionnaire.Logistic regression and chi- squere test was used for data analyzing.    RESULTS: In the present study, 30% of non-smokers, 32.1% ex- smoker and 36.9% of smokers had GHQ of 4 and higher (P = 0.01. In regression analysis, the final model which was controlled for age, sex, socioeconomic statues (including place of residence, marital status and education level showed that the odds ratio of stress in smokers and ex- smoker was significantly higher than in non-smokers (OR = 1.66 and OR = 1.12, respectively.    CONCLUSION: Since in conducted studies, mental problems and stresses have had an important role in people’s smoking, it seems suitable to use the results of this study to present intervention for correct methods of coping with stress towards reducing the prevalence of smoking in the community.Keywords: Cigarette, Stress, Community-based Program.

Sea-Level Change in the Russian Arctic Since the Last Glacial Maximum

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Horton, B.; Baranskaya, A.; Khan, N.; Romanenko, F. A.

2017-12-01

Relative sea-level (RSL) databases that span the Last Glacial Maximum (LGM) to present have been used to infer changes in climate, regional ice sheet variations, the rate and geographic source of meltwater influx, and the rheological structure of the solid Earth. Here, we have produced a quality-controlled RSL database for the Russian Arctic since the LGM. The database contains 394 index points, which locate the position of RSL in time and space, and 244 limiting points, which constrain the minimum or maximum limit of former sea level. In the western part of the Russian Arctic (Barents and White seas,) RSL was driven by glacial isostatic adjustment (GIA) due to deglaciation of the Scandinavian ice sheet, which covered the Baltic crystalline shield at the LGM. RSL data from isolation basins show rapid RSL from 80-100 m at 11-12 ka BP to 15-25 m at 4-5 ka BP. In the Arctic Islands of Franz-Joseph Land and Novaya Zemlya, RSL data from dated driftwood in raised beaches show a gradual fall from 25-35 m at 9-10 ka BP to 5-10 m at 3 ka BP. In the Russian plain, situated at the margins of the formerly glaciated Baltic crystalline shield, RSL data from raised beaches and isolation basins show an early Holocene rise from less than -20 m at 9-11 ka BP before falling in the late Holocene, illustrating the complex interplay between ice-equivalent meltwater input and GIA. The Western Siberian Arctic (Yamal and Gydan Peninsulas, Beliy Island and islands of the Kara Sea) was not glaciated at the LGM. Sea-level data from marine and salt-marsh deposits show RSL rise at the beginning of the Holocene to a mid-Holocene highstand of 1-5 m at 5-1 ka BP. A similar, but more complex RSL pattern is shown for Eastern Siberia. RSL data from the Laptev Sea shelf show RSL at -40- -45 m and 11-14 ka BP. RSL data from the Lena Delta and Tiksi region have a highstand from 5 to 1 ka BP. The research is supported by RSF project 17-77-10130

Yoga reduces perceived stress and exhaustion levels in healthy elderly individuals.

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Lindahl, Eric; Tilton, Katherine; Eickholt, Nicole; Ferguson-Stegall, Lisa

2016-08-01

This study investigated whether a 7-week yoga intervention could improve physical function, perceived stress, and mental/emotional wellness in elderly participants. 8 participants (66.5 ± 0.3 years) attended 2 60-min Hatha yoga sessions/week for 7 weeks, and performed pre- and post-intervention assessments. Balance was assessed using a 5-test battery. Flexibility was measured by sit-and-reach and shoulder flexibility tests. Functional mobility tests included 8-ft up-and-go, 5 chair stands, and 4-m walk. Participants completed SF-12, exhaustion level, and Perceived Stress Scale (PSS) questionnaires. SF-12 Mental Component Summary scores, exhaustion levels, and PSS scores improved post-intervention. No differences were found for physical function measures. Yoga participation can improve mental/emotional wellness, exhaustion levels, and stress levels in elderly individuals, even without measurable improvements in physical function. Clinicians and health practitioners who work with the elderly should consider yoga as a potential therapeutic modality for improving important aspects of quality of life in this population. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reevaluation of the stress-life relation in rolling-element bearings

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Parker, R. J.; Zaretsky, E. V.

1972-01-01

Four groups of 12.7 millimeter diameter vacuum-degassed AISI 52100 balls were tested, each at a maximum Hertz stress in the range of 4.5 times 10 to 9th power to 6.0 times 10 to 9th power N/m2. Tests were run in the five-ball fatigue tester at a contact angle of 30 deg and a shaft speed of 10,000 rpm. The 10 percent fatigue lives at the four stress levels indicated that fatigue life is inversely proportional to maximum Hertz stress raised to the power of 12. This result agrees with a survey of the literature which suggests that a stress-life exponent of approximately 12 is typical of vacuum-processed bearing steels rather than the exponent of 9 which has been generally accepted by the bearing industry.

Effects of salt stress levels on five maize ( Zea mays L.) cultivars at ...

African Journals Online (AJOL)

Effects of salt stress levels on five maize ( Zea mays L.) cultivars at germination stage. ... To investigation the effects of salt stress levels (0, 50, 100, 150, 200 and 250 mM NaCl) on five maize (Zea mays L.) cultivars at ... from 32 Countries:.

Effects of stress on swelling in reactor fuel cladding

International Nuclear Information System (INIS)

Bates, J.F.; Gilbert, E.R.

1977-01-01

The purpose of this report is to describe the effect of stress on swelling in both annealed and 20% cold worked 316 stainless steel. An effect of stress on swelling in irradiated metals has been postulated for some time. Low fluence data confirmed that indeed a tensile stress can increase swelling in irradiated annealed 316 stainless steel and that the maximum swelling occurs at an intermediate stress level which is approximately equal to the proportional elastic limit of the material. The specimens discussed above were examined by transmission electron microscopy and an effect of stress on the microstructure of the annealed and 20% cold worked 316 specimens has been observed. Howver, as yet, copious swelling had not occurred in the 20% cold worked material. Specimens of 20% cold worked 316 fabricated from the same heat of material as those described above have now been irradiated to sufficiently high neutron fluences that swelling has occurred in both the annealed and cold worked conditions. Swelling increases linearly with stress for both materials. However, for solution annealed 316, swelling reaches a maximum at approximately 136 MPa, whereupon further increases in stress result in reduced swelling. It is felt that this reduction in swelling is related to the onset of plastic yielding in the material. The swelling observed in the 20% CW 316 and the solution annealed 316 below the maximum swelling stress can be adequately described by an equation of the form: S = S 0 (1 + Psigma). No strong effect of stress on changing the incubation period associated with void nucleation was found. (Auth.)

The constant threat of terrorism: stress levels and coping strategies amongst university students of Karachi.

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Ahmed, Ayesha Ejaz; Masood, Komal; Dean, Sohni Vicky; Shakir, Tanzila; Kardar, Ahmed Abdul Hafeez; Barlass, Usman; Imam, Syed Haider; Mohmand, Mohammad Ghawar Khan; Ibrahim, Hussain; Khan, Imad Saeed; Akram, Usman; Hasnain, Farid

2011-04-01

To assess the levels of stress in the face of terrorism and the adopted coping strategies, amongst the student population of universities in Karachi. A descriptive, cross sectional study was conducted on undergraduate students from four universities of Karachi. Self-administered questionnaires were filled out by 291 students. Pearson Chi-Square test was used to assess associations between stress levels and different variables at a level of significance of 0.05%. A total of 65.8% of the students had mild stress levels, 91.5% of university students were exposed to terrorism through television, while only 26.5% students reported personal exposure to terrorism. 67.4% students were forbidden by their parents to go out (p = 0.002). Most of those who had self exposure to an attack were the ones whose parents forbade them from going out (p = 0.00). Most commonly used coping strategy was increased faith in religion. Irritability was the most common stress symptom. A majority of students studying in universities of Karachi had mild stress levels due to the constant threat of terrorism whereas a minority had severe stress levels. Possible reasons for resilience and only mild stress levels could be the history of Karachi's internal conflicts and its prolonged duration of being exposed to terrorism. These students who are positive for stress need to be targeted for counseling either through the media or through their universities. More extensive research is needed in this area.

The hippocampal response to psychosocial stress varies with salivary uric acid level

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Goodman, Adam M.; Wheelock, Muriah D.; Harnett, Nathaniel G.; Mrug, Sylvie; Granger, Douglas A.; Knight, David C.

2016-01-01

Uric acid is a naturally occurring, endogenous compound that impacts mental health. In particular, uric acid levels are associated with emotion-related psychopathology (e.g., anxiety and depression). Therefore, understanding uric acid’s impact on the brain would provide valuable new knowledge regarding neural mechanisms that mediate the relationship between uric acid and mental health. Brain regions including the prefrontal cortex, amygdala, and hippocampus underlie stress reactivity and emotion regulation. Thus, uric acid may impact emotion by modifying the function of these brain regions. The present study used functional magnetic resonance imaging (fMRI) during a psychosocial stress task to investigate the relationship between baseline uric acid levels (in saliva) and brain function. Results demonstrate that activity within the bilateral hippocampal complex varied with uric acid concentrations. Specifically, activity within the hippocampus and surrounding cortex increased as a function of uric acid level. The current findings suggest that uric acid levels modulate stress-related hippocampal activity. Given that the hippocampus has been implicated in emotion regulation during psychosocial stress, the present findings offer a potential mechanism by which uric acid impacts mental health. PMID:27725214

The hippocampal response to psychosocial stress varies with salivary uric acid level.

Science.gov (United States)

Goodman, Adam M; Wheelock, Muriah D; Harnett, Nathaniel G; Mrug, Sylvie; Granger, Douglas A; Knight, David C

2016-12-17

Uric acid is a naturally occurring, endogenous compound that impacts mental health. In particular, uric acid levels are associated with emotion-related psychopathology (e.g., anxiety and depression). Therefore, understanding uric acid's impact on the brain would provide valuable new knowledge regarding neural mechanisms that mediate the relationship between uric acid and mental health. Brain regions including the prefrontal cortex, amygdala, and hippocampus underlie stress reactivity and emotion regulation. Thus, uric acid may impact emotion by modifying the function of these brain regions. The present study used functional magnetic resonance imaging (fMRI) during a psychosocial stress task to investigate the relationship between baseline uric acid levels (in saliva) and brain function. Results demonstrate that activity within the bilateral hippocampal complex varied with uric acid concentrations. Specifically, activity within the hippocampus and surrounding cortex increased as a function of uric acid level. The current findings suggest that uric acid levels modulate stress-related hippocampal activity. Given that the hippocampus has been implicated in emotion regulation during psychosocial stress, the present findings offer a potential mechanism by which uric acid impacts mental health. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Gender disparities among the association between cumulative family-level stress & adolescent weight status.

Science.gov (United States)

Hernandez, Daphne C; Pressler, Emily

2015-04-01

To investigate precursors to gender-related obesity disparities by examining multiple family-level stress indices. Analyses was based on adolescents born between 1975 and 1991 to women from the 1979 National Longitudinal Study of Youth data set (N=4762). Three types of family-level stressors were captured from birth to age 15: family disruption and conflict, financial strain, and maternal risky health behaviors, along with a total cumulative risk index. Body mass index was constructed on reference criteria for children outlined by the Centers for Disease Control. Multivariate logistic regressions were conducted for the three types of family stressors and for the total cumulative index. The accumulation of family disruption and conflict and financial stress was positively related to female adolescents being overweight/obese. Childhood exposure to maternal risky health behaviors was positively associated with higher weight status for male adolescents. Total cumulative stress was related to overweight/obesity for females, but not males. Different family-level stress indices are associated with the weight status of female and male adolescents. Combining types of family-level stress into one cumulative index appears to mask these differences. Copyright © 2015 Elsevier Inc. All rights reserved.

Prevalence of depression and its relation to stress level among medical students in Puducherry, India

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S Ganesh Kumar

2017-01-01

Full Text Available Background: Currently, depression among medical students is an important health issue at the global level. There is also a paucity of information on its relation to the stress level. Objective: The aim of this study is to assess the prevalence of depression and its relation to stress level and other factors among medical students. Materials and Methods: A cross-sectional study was conducted among medical students at a tertiary care medical institution in Puducherry, coastal south India. Beck Depression Inventory Scale was used for screening of depression and Cohen's Perceived Stress scale to assess perceived stress level. Data on associated factors were collected by self-administered questionnaire. Results: The overall prevalence of depression was found to be 48.4% (215/444. According to the cutoff scores, 229 (51.6% students scored as normal (0–9, 149 (33.6% as mild (10–18, 60 (13.5% as moderate (19–29, 3 (0.7% as severe (30–40, and 3 (0.7% students scored as very severe (>40 depression. Depression was significantly less among those with mild stress (adjusted odds ratio [OR] = 0.010 and moderate stress level (adjusted OR = 0.099 compared to severe stress level and those without interpersonal problems (adjusted OR = 0.448. Conclusion: Depression is more common among medical students. Stress coping mechanisms and improvement of interpersonal relationship may help to reduce depressive symptoms among medical students.

Military Experience and Levels of Stress and Coping in Police Officers

OpenAIRE

Hartley, Tara A.; Violanti, John M.; Mnatsakanova, Anna; Andrew, Michael E.; Burchfiel, Cecil M.

2013-01-01

Policing is a stressful occupation and working in this environment may make officers more vulnerable to adverse psychological and physiological outcomes. The impact of prior military experience on work stress and coping strategies has not been well-studied in police. The purpose of this cross-sectional study was to examine differences in levels of police-related stress and coping in officers with and without military experience. Participants were 452 police officers from the Buffalo Cardio-me...

Contribution to the study of maximum levels for liquid radioactive waste disposal into continental and sea water. Treatment of some typical samples

International Nuclear Information System (INIS)

Bittel, R.; Mancel, J.

1968-10-01

The most important carriers of radioactive contamination of man are the whole of foodstuffs and not only ingested water or inhaled air. That is the reason why, in accordance with the spirit of the recent recommendations of the ICRP, it is proposed to substitute the idea of maximum levels of contamination of water to the MPC. In the case of aquatic food chains (aquatic organisms and irrigated foodstuffs), the knowledge of the ingested quantities and of the concentration factors food/water permit to determinate these maximum levels, or to find out a linear relation between the maximum levels in the case of two primary carriers of contamination (continental and sea waters). The notion of critical food-consumption, critical radioelements and formula of waste disposal are considered in the same way, taking care to attach the greatest possible importance to local situations. (authors) [fr

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

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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.

Lake-level increasing under the climate cryoaridization conditions during the Last Glacial Maximum

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Amosov, Mikhail; Strelkov, Ivan

2017-04-01

A lake genesis and lake-level increasing during the Last Glacial Maximum (LGM) are the paramount issues in paleoclimatology. Investigating these problems reveals the regularities of lake development and figures out an arid territory conditions at the LGM stage. Pluvial theory is the most prevalent conception of lake formation during the LGM. This theory is based on a fact that the water bodies emerged and their level increased due to torrential rainfalls. In this study, it is paid attention to an alternative assumption of lake genesis at the LGM stage, which is called climate cryoaridization. In accordance with this hypothesis, the endorheic water basins had their level enlarged because of a simultaneous climate aridity and temperature decrease. In this research, a lake-level increasing in endorheic regions of Central Asia and South American Altiplano of the Andes is described. The lake investigation is related to its conditions during the LGM. The study also includes a lake catalogue clearly presenting the basin conditions at the LGM stage and nowadays. The data compilation partly consists of information from an earlier work of Mikhail Amosov, Lake-levels, Vegetation And Climate In Central Asia During The Last Glacial Maximum (EGU2014-3015). According to the investigation, a lake catalogue on 27 lakes showed that most of the water bodies had higher level. This feature could be mentioned for the biggest lakes of the Aral Sea, Lake Balkhash, Issyk-Kul etc. and for the small ones located in the mountains, such as Pamir, Tian-Shan and Tibet. Yet some lakes that are situated in Central Asian periphery (Lake Qinghai and lakes in Inner Mongolia) used to be lower than nowadays. Also, the lake-level increasing of Altiplano turned to be a significant feature during the LGM in accordance with the data of 5 lakes, such as Titicaca, Coipasa-Uyuni, Lejia, Miscanti and Santa-Maria. Most of the current endorheic basins at the LGM stage were filled with water due to abundant

Moderate Level Alcohol During Pregnancy, Prenatal Stress, or Both and Limbic-Hypothalamic-Pituitary-Adrenocortical Axis Response to Stress in Rhesus Monkeys

Science.gov (United States)

Schneider, Mary L.; Moore, Colleen F.; Kraemer, Gary W.

2004-01-01

This study examined the relationship between moderate-level prenatal alcohol exposure, prenatal stress, and postnatal response to a challenging event in 6-month-old rhesus monkeys. Forty-one rhesus monkey (Macaca mulatta) infants were exposed prenatally to moderate level alcohol, maternal stress, or both. Offspring plasma cortisol and…

Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

International Nuclear Information System (INIS)

Okano, Shigetaka; Ihara, Ryohei; Kanamaru, Daisuke; Mochizuki, Masahito

2015-01-01

In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

Decreased total antioxidant levels and increased oxidative stress in ...

African Journals Online (AJOL)

21–25 ... Decreased total antioxidant levels and increased oxidative stress in South ... antioxidant-rich diet and lifestyle changes in T2DM patients would help to avert the .... glycation of proteins and the formation of advanced glycosylation.

Extreme warmth and heat-stressed plankton in the tropics during the Paleocene-Eocene Thermal Maximum.

Science.gov (United States)

Frieling, Joost; Gebhardt, Holger; Huber, Matthew; Adekeye, Olabisi A; Akande, Samuel O; Reichart, Gert-Jan; Middelburg, Jack J; Schouten, Stefan; Sluijs, Appy

2017-03-01

Global ocean temperatures rapidly warmed by ~5°C during the Paleocene-Eocene Thermal Maximum (PETM; ~56 million years ago). Extratropical sea surface temperatures (SSTs) met or exceeded modern subtropical values. With these warm extratropical temperatures, climate models predict tropical SSTs >35°C-near upper physiological temperature limits for many organisms. However, few data are available to test these projected extreme tropical temperatures or their potential lethality. We identify the PETM in a shallow marine sedimentary section deposited in Nigeria. On the basis of planktonic foraminiferal Mg/Ca and oxygen isotope ratios and the molecular proxy [Formula: see text], latest Paleocene equatorial SSTs were ~33°C, and [Formula: see text] indicates that SSTs rose to >36°C during the PETM. This confirms model predictions on the magnitude of polar amplification and refutes the tropical thermostat theory. We attribute a massive drop in dinoflagellate abundance and diversity at peak warmth to thermal stress, showing that the base of tropical food webs is vulnerable to rapid warming.

Stress at work: development of the Stress Perception Questionnaire of Rome (SPQR), an ad hoc questionnaire for multidimensional assessment of work related stress.

Science.gov (United States)

Cinti, M E; Cannavò, M; Fioravanti, M

2017-01-01

Stress is an emotional condition, mostly experienced as negative, initially identified and defined by Selye in the mid-thirties of the last Century. Since the first definition, stress concerns the adaptation pro- cess mostly related to environmental changes. An application of stress focuses on the evaluation of its interference on work conditions, and the scientific evidence on work related stress is very ample and rich. We are proposing a new ad hoc questionnaire for the multidimensional assessment of work related stress, called Stress Perception Question- naire of Rome (SPQR) composed of 50 items. The development of this questionnaire is based on a multi-step process: a) Identification of all the relevant topics to work related stress and areas in the scientific evidence and their transformation on specific contents of 60 tentative items; b) Exploratory factor analysis aimed to identify the best items (50) which could guarantee the maximum convergence on single scales (8), and the minimum redundancy between scales; c) Validation of the 8 scales' structure by a confirmatory factor analysis (fully achieved); d) Factor analysis for a second level factor resulting in a single factor identified as the questionnaire total score (Stress Score); d) Reliability analysis of the questionnaire total score and the single scale scores (at optimum level); e) Validation by external criteria of work related stress identified in the presence of personal violence episodes experienced by a group of health workers with different professional profiles and from two different hospitals in Rome. Our results show that the SPQR is a useful and sensitive tool for assessing the presence of emotional stress related problems identifiable in a work environment. The advantage of this questionnaire is that it allows for a multidimensional description of the different components of this problematic area besides its ability to quantify the overall stress level of those who have been administered

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).

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.

Organizational politics, nurses' stress, burnout levels, turnover intention and job satisfaction.

Science.gov (United States)

Labrague, L J; McEnroe-Petitte, D M; Gloe, D; Tsaras, K; Arteche, D L; Maldia, F

2017-03-01

This is a research report examining the influence of organizational politics perceptions on nurses' work outcomes (job satisfaction, work stress, job burnout and turnover intention). Organizational politics is a phenomenon common in almost all institutions and is linked with undesirable consequences in employees. Despite the plethora of research around the world on this topic, studies describing organizational politics in nursing remain underexplored. A cross-sectional research design was utilized in this study. One hundred sixty-six (166) nurses participated. Five standardized tools were used: the Job Satisfaction Index, the Job Stress Scale, the Burnout Measure Scale, the Turnover Intention Inventory Scale and the Perception of Organizational Politics Scale. Nurses employed both in private and government-owned hospitals perceived moderate levels of organizational politics. Positive correlations were identified between perceived organizational politics and job stress, turnover intention and job burnout. Negative correlations were found between perceived organizational politics and job satisfaction. Perceptions of workplace politics in Filipino nurses were lower when compared to findings in other international studies. A strong link was found between organizational politics perceptions and the four job outcomes (stress and burnout levels, turnover intention and job satisfaction). Use of a self-reporting questionnaire and exclusion of nurses from other provinces. Perceived organizational politics predicted nurses' stress and burnout levels, turnover intention and job satisfaction. The findings of this study may provide a valuable perspective of this organizational issue and could assist policymakers and nurse administrators in formulating interventions that could minimize the effect of workplace politics. © 2016 International Council of Nurses.

Academic stress levels were positively associated with sweet food consumption among Korean high-school students.

Science.gov (United States)

Kim, Yeonsoo; Yang, Hye Young; Kim, Ae-Jung; Lim, Yunsook

2013-01-01

The objectives of the present study were to identify the association among levels of persistent academic stress, appetite, and dietary habits and to determine the specific types of sweet foods consumed by Korean high-school students according to their academic stress levels. The study participants included 333 high-school students in the 10th to 12th grades in Kyunggi Province, Korea. The level of academic stress was scored with a 75-item academic stress scale and was categorized as high, medium, or low. A food-frequency questionnaire was used to measure the sugar intake from sweet foods. Korean high-school students with a high academic stress level had larger meals than the other students. Compared with students with low academic stress, the students with high academic stress had a higher frequency of sugar intake from the following food types: confectionaries, candies and chocolates, breads, and flavored milk. Moreover, compared with students with low academic stress, the students with high academic stress had a higher total intake of sugar from the following food types: confectionaries, candies, chocolates, flavored milk, traditional Korean beverages, and spicy, sweet, and fried rice cakes. Unhealthy stress-related food choices may compromise high-school students' health and contribute to their morbidity. The findings of the present study could be used to help nutritionists develop effective strategies for nutritional education and counseling to improve adolescent health. Copyright © 2013 Elsevier Inc. All rights reserved.

Can community structure track sea-level rise? Stress and competitive controls in tidal wetlands.

Science.gov (United States)

Schile, Lisa M; Callaway, John C; Suding, Katharine N; Kelly, N Maggi

2017-02-01

Climate change impacts, such as accelerated sea-level rise, will affect stress gradients, yet impacts on competition/stress tolerance trade-offs and shifts in distributions are unclear. Ecosystems with strong stress gradients, such as estuaries, allow for space-for-time substitutions of stress factors and can give insight into future climate-related shifts in both resource and nonresource stresses. We tested the stress gradient hypothesis and examined the effect of increased inundation stress and biotic interactions on growth and survival of two congeneric wetland sedges, Schoenoplectus acutus and Schoenoplectus americanus . We simulated sea-level rise across existing marsh elevations and those not currently found to reflect potential future sea-level rise conditions in two tidal wetlands differing in salinity. Plants were grown individually and together at five tidal elevations, the lowest simulating an 80-cm increase in sea level, and harvested to assess differences in biomass after one growing season. Inundation time, salinity, sulfides, and redox potential were measured concurrently. As predicted, increasing inundation reduced biomass of the species commonly found at higher marsh elevations, with little effect on the species found along channel margins. The presence of neighbors reduced total biomass of both species, particularly at the highest elevation; facilitation did not occur at any elevation. Contrary to predictions, we documented the competitive superiority of the stress tolerator under increased inundation, which was not predicted by the stress gradient hypothesis. Multifactor manipulation experiments addressing plant response to accelerated climate change are integral to creating a more realistic, valuable, and needed assessment of potential ecosystem response. Our results point to the important and unpredicted synergies between physical stressors, which are predicted to increase in intensity with climate change, and competitive forces on biomass as

Effects of soil drought stress on plant regeneration efficiency and endogenous hormone levels of immature embryos in wheat (Triticum aestivum L.)

International Nuclear Information System (INIS)

Bie, X.; Wang, K.; Liu, C.; Du, L.

2017-01-01

In this study, the water supply in soil for wheat mother donor plants was controlled, leading to drought stress conditions, and the relative soil water content (RSWC) was measured in different soil depths. The immature embryos of common wheat (Triticum aestivum L.) 13 days post anthesis (DPA) were used to test regeneration capacity. The accumulation of the plant growth regulators (PGRs) including abscisic acid (ABA), indole-3-acetic acid (IAA), and hydrogen peroxide (H2O2) in the wheat embryos grown under the two conditions was measured. The results indicated that RSWC difference between the drought treatment and the irrigated control was more than 13% at the various soil depths, with the maximum difference was observed at 40 cm depth. Tissue culture evaluation showed that the plant regeneration efficiency of the immature embryos grown under drought stress treatment was significantly higher than that of the tissues grown under the control condition. Assay for PGR found that the drought stress caused obviously increased concentration of endogenous ABA and H2O2, and slightly decreased level of IAA in the target tissues. Therefore, it seems that the concentration of endogenous ABA, IAA, and H2O2 in immature wheat embryos is very important in regeneration capacity. Drought stress can improve the regeneration capacity by changing the levels of ABA, IAA, and H2O2. Our results would be helpful to efficient development of genetically modified wheat plants through improvement of regeneration via manipulating the endogenous PGRs. (author)

Abiotic stressors and stress responses: What commonalities appear between species across biological organization levels?

International Nuclear Information System (INIS)

Sulmon, Cécile; Baaren, Joan van; Cabello-Hurtado, Francisco; Gouesbet, Gwenola; Hennion, Françoise; Mony, Cendrine; Renault, David; Bormans, Myriam; El Amrani, Abdelhak; Wiegand, Claudia; Gérard, Claudia

2015-01-01

Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental complexity. We provide new insights into the understanding of the impact of molecular and cellular responses on individual and population dynamics and assess the potential related effects on communities and ecosystem functioning. - Highlights: • Responses to chemical and thermal stressors are reviewed across organization levels. • Common responses between taxa are evident at the molecular and cellular scales. • At individual level, energy allocation connects species-specific stress responses. • Commonality decreases at higher levels due to increasing environmental complexity. - The commonality of stress responses to chemical and thermal stressors among taxa is evident at the molecular and cellular scales but remains unclear at higher levels of organization

Induced thermal stress on serotonin levels in the blue swimmer crab, Portunus pelagicus

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Saravanan Rajendiran

2016-03-01

Full Text Available The temperature of habitat water has a drastic influence on the behavioral, physiological and biochemical mechanisms of crustaceans. Hyperglycemia is a typical response of many aquatic animals to harmful physical and chemical environmental changes. In crustaceans increased circulating crustacean hyperglycemic hormone (CHH and hyperglycemia are reported to occur following exposure to several environmental stress. The biogenic amine, serotonin has been found to modulate the CHH levels and oxidation of serotonin into its metabolites is catalysed by monoamine oxidase. The blue swimmer crab, Portunus pelagicus is a dominant intertidal species utilized throughout the indo-pacific region and is a particularly important species of Palk bay. It has high nutritional value and delicious taste and hence their requirements of capture and cultivation of this species are constantly increasing. This species experiences varying and increasing temperature levels as it resides in an higher intertidal zone of Thondi coast. The present study examines the effect of thermal stress on the levels of serotonin and crustacean hyperglycemic hormone in the hemolymph of P. pelagicus and analyzes the effect of the monoamine oxidase inhibitor, pargyline on serotonin and CHH level after thermal stress. The results showed increased levels of glucose, CHH and serotonin on exposure to 26 °C in control animals. Pargyline injected crabs showed highly significant increase in the levels of CHH and serotonin on every 2 °C increase or decrease in temperature. A greater CHH level of 268.86±2.87 fmol/ml and a greater serotonin level of 177.69±10.10 ng/ml was observed at 24 °C. This could be due to the effect of in maintaining the level of serotonin in the hemolymph and preventing its oxidation, which in turn induces hyperglycemia by releasing CHH into hemolymph. Thus, the study demonstrates the effect of thermal stress on the hemolymph metabolites studied and the role of

Induced thermal stress on serotonin levels in the blue swimmer crab, Portunus pelagicus.

Science.gov (United States)

Rajendiran, Saravanan; Muhammad Iqbal, Beema Mahin; Vasudevan, Sugumar

2016-03-01

The temperature of habitat water has a drastic influence on the behavioral, physiological and biochemical mechanisms of crustaceans. Hyperglycemia is a typical response of many aquatic animals to harmful physical and chemical environmental changes. In crustaceans increased circulating crustacean hyperglycemic hormone (CHH) and hyperglycemia are reported to occur following exposure to several environmental stress. The biogenic amine, serotonin has been found to modulate the CHH levels and oxidation of serotonin into its metabolites is catalysed by monoamine oxidase. The blue swimmer crab, Portunus pelagicus is a dominant intertidal species utilized throughout the indo-pacific region and is a particularly important species of Palk bay. It has high nutritional value and delicious taste and hence their requirements of capture and cultivation of this species are constantly increasing. This species experiences varying and increasing temperature levels as it resides in an higher intertidal zone of Thondi coast. The present study examines the effect of thermal stress on the levels of serotonin and crustacean hyperglycemic hormone in the hemolymph of P. pelagicus and analyzes the effect of the monoamine oxidase inhibitor, pargyline on serotonin and CHH level after thermal stress. The results showed increased levels of glucose, CHH and serotonin on exposure to 26 °C in control animals. Pargyline injected crabs showed highly significant increase in the levels of CHH and serotonin on every 2 °C increase or decrease in temperature. A greater CHH level of 268.86±2.87 fmol/ml and a greater serotonin level of 177.69±10.10 ng/ml was observed at 24 °C. This could be due to the effect of in maintaining the level of serotonin in the hemolymph and preventing its oxidation, which in turn induces hyperglycemia by releasing CHH into hemolymph. Thus, the study demonstrates the effect of thermal stress on the hemolymph metabolites studied and the role of pargyline in elevating the

An investigation of the maximum penetration level of a photovoltaic (PV) system into a traditional distribution grid

Science.gov (United States)

Chalise, Santosh

Although solar photovoltaic (PV) systems have remained the fastest growing renewable power generating technology, variability as well as uncertainty in the output of PV plants is a significant issue. This rapid increase in PV grid-connected generation presents not only progress in clean energy but also challenges in integration with traditional electric power grids which were designed for transmission and distribution of power from central stations. Unlike conventional electric generators, PV panels do not have rotating parts and thus have no inertia. This potentially causes a problem when the solar irradiance incident upon a PV plant changes suddenly, for example, when scattered clouds pass quickly overhead. The output power of the PV plant may fluctuate nearly as rapidly as the incident irradiance. These rapid power output fluctuations may then cause voltage fluctuations, frequency fluctuations, and power quality issues. These power quality issues are more severe with increasing PV plant power output. This limits the maximum power output allowed from interconnected PV plants. Voltage regulation of a distribution system, a focus of this research, is a prime limiting factor in PV penetration levels. The IEEE 13-node test feeder, modeled and tested in the MATLAB/Simulink environment, was used as an example distribution feeder to analyze the maximum acceptable penetration of a PV plant. The effect of the PV plant's location was investigated, along with the addition of a VAR compensating device (a D-STATCOM in this case). The results were used to develop simple guidelines for determining an initial estimate of the maximum PV penetration level on a distribution feeder. For example, when no compensating devices are added to the system, a higher level of PV penetration is generally achieved by installing the PV plant close to the substation. The opposite is true when a VAR compensator is installed with the PV plant. In these cases, PV penetration levels over 50% may be

Stress levels and depressive symptoms in NICU mothers in the early postpartum period.

Science.gov (United States)

Alkozei, Anna; McMahon, Erin; Lahav, Amir

2014-11-01

This study examined whether particular maternal and infant factors can identify mothers at risk for increased stress upon admission to the neonatal intensive care unit (NICU). Eighty-five mothers of preterm infants (25-34 weeks gestation) were assessed using the Parental Stressor Scale (PSS:NICU) and the Edinburgh Postnatal Depression Scale (EPDS) within 3.24 ± 1.58 d postpartum. Hierarchical linear regression models were used to determine the extent to which maternal stress is influenced by individual factors. Fifty-two percent of mothers experienced increased stress (PSS:NICU score ≥3) and 38% had significant depressive symptoms (EPDS score ≥10). Stress related to alterations in parental role was the most significant source of stress among NICU mothers. Distance from the hospital and married marital status were significant predictors for stress related to alterations in parental role (p = 0.003) and NICU sights and sounds (p = 0.01), respectively. Higher stress levels were associated with higher depressive scores (p = 0.001). Maternal mental health factors, demographic factors, pregnancy factors and infant characteristics were not associated with increased stress. Elevated stress levels and depressive symptoms are already present in mothers of preterm infants upon NICU admission. Being married or living long distance from the hospital is associated with higher stress. Future work is needed to develop effective interventions for alleviating stress in NICU mothers and preventing its potential development into postnatal depression.

EVALUATION OF PERCEIVED STRESS LEVELS AND ITS SOURCE AMONG DENTAL STUDENTS: A CROSS-SECTIONAL STUDY

OpenAIRE

Praveen K; Christofer; Purna Singh; Shivanand

2016-01-01

CONTEXT Recent reports show high amount of academic stress among the students and chronic stress is shown to have a negative effect on cognitive functioning and learning of students. AIMS The purpose of study was to determine the prevalence of self-perceived stress among dental students and to observe any possible association between the levels of stress and (a) academic year, (b) motivation to study dental science, (c) medium of study at 10+2 level, (d) mother tongue, (e...

Effects of Swimming Training on Stress Levels of the Students Aged 11-13

Science.gov (United States)

Köroglu, Mihraç; Yigiter, Korkmaz

2016-01-01

The purpose of this research was to determine the effects of the swimming training program on stress levels of the students ages 11-13. To this end, 60 students from Private Sahin School in the Sakarya city participated in the study voluntarily. 60 students were divided into two groups and each group was included 30 students. Stress Level Scale II…

Project ES3: attempting to quantify and measure the level of stress.

Science.gov (United States)

Aguiló, Jordi; Ferrer-Salvans, Pau; García-Rozo, Antonio; Armario, Antonio; Corbí, Ángel; Cambra, Francisco J; Bailón, Raquel; González-Marcos, Ana; Caja, Gerardo; Aguiló, Sira; López-Antón, Raúl; Arza-Valdés, Adriana; Garzón-Rey, Jorge M

2015-11-01

The WHO has qualified stress as a 'world epidemic' due to its increasingly greater incidence on health. The work described in this paper represents an attempt to objectively quantify the level of stress. The aim of the method developed here is to measure how close or how far a subject is from a situation that can be considered 'normal' in medical and social terms. The literature on the pathophysiology of stress and its methods of study in experiments on both animals and humans was reviewed. Nine prospective observational studies were undertaken with different types of subjects and stressors covering the different types of stress. The results of the literature review made it possible to identify the different types of stress, the indicators that yield significant results, the psychometric tests and the well-documented 'stressors'. This material was then used to design the general method and the details of the nine clinical trials. The preliminary results obtained in some of the studies were used to validate the indicators as well as the efficacy of the techniques used experimentally to diminish stress or to produce it. The early results obtained in the experimental trials show that we are on the right path towards defining and validating multivariable markers for quantifying levels of stress and also suggest that the method can be applied in a similar way to the study of mental disorders.

The relationship between job stress and burnout levels of oncology nurses

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Rujnan Tuna

2014-01-01

Full Text Available Objective: Job stress and burnout levels of oncology nurses increase day-by-day in connection with rapidly increasing cancer cases worldwide as well as in Turkey. The purpose of this study was to establish job stress and burnout levels of oncology nurses and the relationship in between. Methods: The sample of this descriptive study comprised of 189 nurses that are selected by nonprobability sampling method, employed by 11 hospitals in Istanbul. Survey form of 20 questions, Job Stressors Scale and Maslach Burnout Inventory (MBI were used during collection of data. Data were evaluated using percentage, Kruskal-Wallis, Mann-Whitney U and Spearman correlation analyses. Results: In the study, there was a positively weak correlation between "Work Role Ambiguity" subdimension of Job Stressors Scale and "Emotional Exhaustion" and "Personal Accomplishment" subdimensions, whereas a positively weak and medium correlation was encountered between "Work Role Conflict" subdimension and "Emotional Exhaustion" and "Depersonalization" subdimensions. A negatively weak correlation was found between "Work Role Overload" subdimension and "Emotional Exhaustion" and "Depersonalization" subdimensions. Conclusion: A significant relationship was established between subdimensions of job stress level and of burnout level, that a lot of oncology nurses who have participated in the study wanted to change their units, because of the high attrition rate.

Association between oxidative stress index and serum lipid levels in healthy young adults

International Nuclear Information System (INIS)

Turkdogan, K.E.

2014-01-01

Objectives: To investigate the relationship between lipid levels and oxidative stress index in healthy young adults. Methods: The study was camed out at the Department of Emergency Service, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey, between January 2011 and July 2012. A total of 100 healthy adult volunteers were enrolled in the study. Venous blood samples (10 ml) were collected from all individuals, and serum lipid parameters, total antioxidant capacity and total oxidative levels were studied. SPSS 15 was used for statistical analysis. Results: Overall, there were 84 (84%) males and 16 (16%) females. The mean age of the male population was 30+-3 years, while that of the females was 31+-3 years. Overall age ranged from 25 to 35 years. A statistically significant correlation was found between the oxidative stress index and serum cholesterol (p<0.001; r=0.596), triglyceride (p<0.001; r=0.476) and low-density lipoprotein levels (p<0.001; r=0.318). However, no significant correlation was found between oxidative stress index and serum high-density lipoprotein levels (p=0.564; r=0.058). Conclusion: The results showed that even at an early age, there is a direct linear correlation between oxidative stress and serum lipid levels. (author)

Displacement behaviour is associated with reduced stress levels among men but not women.

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Changiz Mohiyeddini

Full Text Available Sex differences in the ability to cope with stress may contribute to the higher prevalence of stress-related disorders among women compared to men. We recently provided evidence that displacement behaviour--activities such as scratching and face touching--represents an important strategy for coping with stressful situations: in a healthy population of men, displacement behaviour during a social stress test attenuated the relationship between anxiety experienced prior to this test, and the subsequent self-reported experience of stress. Here, we extend this work to look at physiological and cognitive (in addition to self-reported measures of stress, and study both men and women in order to investigate whether sex moderates the link between displacement behaviour and the response to stress. In a healthy study population, we quantified displacement behaviour, heart rate and cognitive performance during the Trier Social Stress Test, and used self-report questionnaires to assess the experience of stress afterwards. Men engaged in displacement behaviour about twice as often as women, and subsequently reported lower levels of stress. Bivariate correlations revealed that for men, higher rates of displacement behaviour were associated with decreased self-reported stress, fewer mistakes in the cognitive task and a trend towards lower heart rate; no relationships between displacement behaviour and stress measures were found for women. Moreover, moderation analyses revealed that high rates of displacement behaviour were associated with lower stress levels in men but not in women, and that high displacement behaviour rates were associated with poorer cognitive performance in women, but not men. These results point to an important sex difference in coping strategies, and highlight new avenues for research into sex biases in stress-related disorders.

Laser quench hardening of steel: Effects of superimposed elastic pre-stress on the hardness and residual stress distribution

Science.gov (United States)

Meserve, Justin

Cold drawn AISI 4140 beams were LASER surface hardened with a 2 kW CO2 LASER. Specimens were treated in the free state and while restrained in a bending fixture inducing surface tensile stresses of 94 and 230 MPa. Knoop hardness indentation was used to evaluate the through thickness hardness distribution, and a layer removal methodology was used to evaluate the residual stress distribution. Results showed the maximum surface hardness attained was not affected by pre-stress during hardening, and ranged from 513 to 676 kg/mm2. The depth of effective hardening varied at different magnitudes of pre-stress, but did not vary proportionately to the pre-stress. The surface residual stress, coinciding with the maximum compressive residual stress, increased as pre-stress was increased, from 1040 MPa for the nominally treated specimens to 1270 MPa for specimens pre-stressed to 230 MPa. The maximum tensile residual stress observed in the specimens decreased from 1060 MPa in the nominally treated specimens to 760 MPa for specimens pre-stressed to 230 MPa. Similarly, thickness of the compressive residual stress region increased and the depth at which maximum tensile residual stress occurred increased as the pre-stress during treatment was increased Overall, application of tensile elastic pre-stress during LASER hardening is beneficial to the development of compressive residual stress in AISI 4140, with minimal impact to the hardness attained from the treatment. The newly developed approach for LASER hardening may support efforts to increase both the wear and fatigue resistance of parts made from hardenable steels.

Stress among nurses: an examination of salivary cortisol levels on work and day off

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Maria Cecilia Pires da Rocha

2013-10-01

Full Text Available The present study evaluates the use of salivary cortisol concentration as a physiological index of the stress level among nurses on their work day and day off and correlates it with the questionnaire used to measure occupational stress in nurses (Inventário de Estresse em Enfermeiros - IEE. This is a comparative, cross-sectional descriptive study in which sociodemographic data, IEE results and salivary cortisol levels were used. Fifty-seven nurses participated in the study (80.7% females and a mean age of 37.1 years old. The IEE average score was 124.5. The average cortisol level was 564.1 ng/m on work day and 354.1 ng/mL on day off. Nurses who had double workdays presented high values of salivary cortisol during the work day (638.1 ng/mL. In conclusion, salivary cortisol identified the nurses’ stress level, and differences were found between a work day and day off. On the nurses’ day off, their salivary cortisol levels and stress scores were lower.

Transmission of vertical stress in a real soil profile. Part II

DEFF Research Database (Denmark)

Lamandé, Mathieu; Schjønning, Per

2011-01-01

used rated tyre inflation pressures for traffic in the field (≤10 km h−1 driving speed). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil at 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 tyre–soil interface were measured in separate tests by 17 stress transducers across the width of the tyres. The level of maximum stress at 0.3 m depth was related to the surface-related stress expressions like the mean...... ground pressure and the tyre inflation pressure. The maximum stresses measured at 0.9 m depth were correlated with the wheel load (57 and 60 kPa at 60 kN load; 27 and 25 kPa at 30 kN load) and did not reflect the surface-related stress expressions. Our results show that the use of wide, low pressure...

Assessment of stress due to hot ambience in donkeys from arid tracts in India

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Kataria N.

2010-11-01

Full Text Available To assess the stress due to hot ambience in donkeys from arid tracts in Rajasthan state, India, serum prolactin and cortisol levels were determined by radioimmunoassay. The blood samples to harvest the serum were collected from the same animals during moderate (maximum temperature of 28 C - 29 C and hot (maximum temperature of 45 C- 46 C ambiences. During hot ambience the animals showed significantly (p0.05 higher levels of serum prolactin and cortisol when compared to the moderate ambience. The mean rise in prolactin was 4.42 times whereas cortisol levels were 4.22 times higher. Further a multiple fold rise in serum prolactin clearly suggested that it can also be used as an indicator of stress in donkeys along with the cortisol.

Stress levels of critical care doctors in India: A national survey.

Science.gov (United States)

Amte, Rahul; Munta, Kartik; Gopal, Palepu B

2015-05-01

Doctors working in critical care units are prone to higher stress due to various factors such as higher mortality and morbidity, demanding service conditions and need for higher knowledge and technical skill. The aim was to evaluate the stress level and the causative stressors in doctors working in critical care units in India. A two modality questionnaire-based cross-sectional survey was conducted. In manual mode, randomly selected delegates attending the annual congress of Indian Society of Critical Care Medicine filled the questionnaire. In the electronic mode, the questionnaires were E-mailed to critical care doctors. These questionnaires were based on General Health Questionnaire-12 (GHQ-12). Completely filled 242 responses were utilized for comparative and correlation analysis. Prevalence of moderate to severe stress level was 40% with a mean score of 2 on GHQ-12 scale. Too much responsibility at times and managing VIP patients ranked as the top two stressors studied, while the difficult relationship with colleagues and sexual harassment were the least. Intensivists were spending longest hours in the Intensive Care Unit (ICU) followed by pulmonologists and anesthetists. The mean number of ICU bed critical care doctors entrusted with was 13.2 ± 6.3. Substance abuse to relieve stress was reported as alcohol (21%), anxiolytic or antidepressants (18%) and smoking (14%). Despite the higher workload, stress levels measured in our survey in Indian critical care doctors were lower compared to International data. Substantiation of this data through a wider study and broad-based measures to improve the quality of critical care units and quality of the lives of these doctors is the need of the hour.

Remote detection of air pollution stress to vegetation - Laboratory-level studies

Science.gov (United States)

Westman, Walter E.; Price, Curtis V.

1987-01-01

An experimental investigation of the role of leaf chemistry, anatomy, moisture content, and canopy density on spectral reflectance in healthy and pollution stressed western conifer needles and broad-leafed species of California coastal sage scrub is presented. Acid mist at a level of pH 2.0 is found to more severely effect chlorophyll loss and leaf death than ozone at a level of 0.2 ppm for a four-week period. Both pollutants cause water loss, affecting Bands 4 and 5 in nonlinear ways. The infrared bands initially rise as free water is lost, and subsequently, scattering and reflectance decline. The net effect is shown to be a reduction in TM 4/3 and a rise in TM 5/4 with pollution stress. Under more severe pollution stresses, the decline of leaf area indices due to accelerated leaf drop accentuates the expected TM 4/3 and TM 5/4 changes.

Gaharu Leaf Extract Water Reduce MDA and 8-OHdG Levels and Increase Activities SOD and Catalase in Wistar Rats Provided Maximum Physical Activity

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I Made Oka Adi Parwata

2016-09-01

Full Text Available Background: Oxidative stress occurs due to an imbalance of the number of free radicals by the number of endogenous antioxidant produced by the body i.e. Superoxide Dismutase (SOD, Gluthathione Peroxidase (GPx, and Catalase. The imbalance between the number of free radicals and antioxidants can be overcome with the endogenous antioxidant intake that exogenous oxidative stress can be reduced. One of exogenous antioxidants is natural Gaharu leaf water extract. Objective: This research focus on the effect of Gaharu leaf water extract in reducing MDA and 8-OHdG and increase the activity of SOD and Catalase. Methods: This study was an experimental with post only controls group design. Experiment was divided  into 5 groups of wistar rats, each consisting of 5 animals, i.e. negative control group without extract [K (-], treatment 1 treated 50 mg/kg BW/day of the extract (T1, treatment 2 treated 100 mg/kg BW/day of the extract (T2, treatment 3 treated 200 mg/ kg BW/day of the extract (T3, and positive control group [K (+] treated with vitamin Cat a dose 50 mg/kg BW/day. All groups treated for 10 weeks. Every day, before treatment, each group was given a maximum swimming activity for 1.5 hours for 10 weeks. ELISA was used to measure MDA, 8-OHdG, SOD, and Catalase activities. Result: The research results showed that treatment of extract of  leaves of Gaharu with an higher dose from 50 mg/kg BW up to 200 mg/ kg BW significantly decline (p <0.05 levels of MDA with the average ranging from 6.37±0.23, 5,56±0.27 and 4.32±0.27, 8-OHdG with a mean of 1.64±0.11, 1.26±0.46, and 1.09±0.17. On the other hand the treatment also increase SOD activity with less ranging from 12.15±1.04, 15.70±2.02, and 18.84±1.51, and Catalase ranging from 6,68±0.63, 8.20±1.14 and 9.29±0,79 in the blood of Wistar rats were given a maximum activity compared to the negative control group. This is probably higher phenol compounds (bioflavonoids quantity content of the extract

What characterizes persons with high levels of perceived stress in Denmark? A national representative study.

Science.gov (United States)

Nielsen, Line; Curtis, Tine; Kristensen, Tage S; Rod Nielsen, Naja

2008-06-01

Stress is a growing public health problem, but there are only a few studies with national representative samples on the occurrence of stress. The aim of this study was to assess the level of stress, measured by the Perceived Stress Scale, in Denmark, and to identify and characterize the group with high levels of stress by factors measured at both the individual and neighbourhood levels in a national representative sample of the Danish population. The 10,022 participants in the National Health Interview Survey 2005 were asked about perceived stress and individual factors in a cross-sectional design. Information on neighbourhood factors was derived from a national registry. Data were analysed by means of logistic regression models. Low education, heavy smoking, physical inactivity, lack of social network and poor working conditions were associated with perceived stress. For women, living in a neighbourhood with low average education, and for men, living in a neighbourhood with a high rate of crime and a low degree of ethnic diversity, were associated with higher perceived stress. Perceived stress was also related to indicators of morbidity. The group with high perceived stress is characterized by individual and neighbourhood factors with negative impacts on quality of life and risk of illness. This knowledge can guide future stress prevention efforts. Additionally, the results suggest a negative social component where perceived stress, unhealthy lifestyle and low social status are accumulated, and perceived stress might be used as a measure to identify groups characterized by accumulation of risk factors.

Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

Science.gov (United States)

Hacham, Yael; Matityahu, Ifat; Amir, Rachel

2017-07-01

Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

The genetics of aging in optimal and stressful environments

International Nuclear Information System (INIS)

Parsons, P.A.

1978-01-01

The genetic basis of aging in Drosophila varies according to environment, as shown by variations in temperatures and levels of 60 Co-γ irradiation. Under conditions of extreme stress large additive differences occur not found under less acute stresses. In addition, longevities of strains are not necessarily correlated across levels of 60 C0-γ irradiation or temperatures, so that studies of the genetics of aging are not only relevant to the environment selected. Given these results on experimental animals, it appears impossible to separate clearly genetic and environmental factors determining longevity in man - a conclusion that in any case appears likely from human studies. In experimental organisms such as Drosophila, differences between genotypes for longevity are magnified under stress compared with optimal environments. Hybrid and heterozygote superiority frequently occur for density-independent physical stresses of the environment as well as density-dependent behavioral stresses due to crowding levels. It is argued that these conclusions apply to man, so that for maximum longevity genotypes are likely to be highly heterozygous. (author)

Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress. III. Vegetation water stress

Science.gov (United States)

Porporato, A.; Laio, F.; Ridolfi, L.; Rodriguez-Iturbe, I.

The reduction of soil moisture content during droughts lowers the plant water potential and decreases transpiration; this in turn causes a reduction of cell turgor and relative water content which brings about a sequence of damages of increasing seriousness. A review of the literature on plant physiology and water stress shows that vegetation water stress can be assumed to start at the soil moisture level corresponding to incipient stomatal closure and reach a maximum intensity at the wilting point. The mean crossing properties of these soil moisture levels crucial for water stress are derived analytically for the stochastic model of soil moisture dynamics described in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe. Adv. Water Res. 24 (7) (2001) 707-723). These properties are then used to propose a measure of vegetation water stress which combines the mean intensity, duration, and frequency of periods of soil water deficit. The characteristics of vegetation water stress are then studied under different climatic conditions, showing how the interplay between plant, soil, and environment can lead to optimal conditions for vegetation.

B-type natriuretic peptide (BNP serum levels in rats after forced repeated swimming stress

Directory of Open Access Journals (Sweden)

Almira Hadžovic-Džuvo

2011-02-01

Full Text Available Aim To estimate the effects of forced repeated swimming stress on BNP serum levels in rats. Methods Adult male Wistar rats weighting between 280-330 g were divided into two groups: control group (n =8 and stress group (n =8. Rats in the stress group were exposed to forced swimming stress daily, for 7 days. The rats were forced to swim in plastic tanks (90 cm wide, 120 cm deep containing tap water (temperature ca. 25°C. The depth of water was 40 cm. Duration of each swimming session progressively increased from 10 minutes on the irst day to 40 minutes on days 6 and 7. Rats were sacriiced and blood was drawn from abdominal aorta for BNP analysis immediately after the last swimming session. B-type natriuretic serum level was determined by ELISA method using RAT BNP-32 kit (Phoenix Pharmaceutical Inc.. Results There was no statistically signiicant difference between mean BNP serum level in the stress group after the swimming period (0.81±0.14 ng/ml as compared to the unstressed group of rats (0.8 ±0.08ng/ml. After the swimming period mean body weight slightly decreased in the stress group in comparison with values before stress period (296.3 g vs.272.8 g, but this difference was not statistically signiicant. The stress period had no inluence on food intake in the stress rat group. Conclusion The workload consisting of 40-minutes long swimming session is not suficient to provoke BNP release from myocardium in rats.

B-type natriuretic peptide (BNP) serum levels in rats after forced repeated swimming stress.

Science.gov (United States)

Hadzovic-Dzuvo, Almira; Valjevac, Amina; Avdagić, Nesina; Lepara, Orhan; Zaćiragić, Asija; Jadrić, Radivoj; Alajbegović, Jasmin; Prnjavorac, Besim

2011-02-01

To estimate the effects of forced repeated swimming stress on BNP serum levels in rats. Adult male Wistar rats weighting between 280-330 g were divided into two groups: control group (n = 8) and stress group (n = 8). Rats in the stress group were exposed to forced swimming stress daily, for 7 days. The rats were forced to swim in plastic tanks (90 cm wide, 120 cm deep) containing tap water (temperature ca. 25 degrees C). The depth of water was 40 cm. Duration of each swimming session progressively increased from 10 minutes on the first day to 40 minutes on days 6 and 7. Rats were sacrificed and blood was drawn from abdominal aorta for BNP analysis immediately after the last swimming session. B-type natriuretic serum level was determined by ELISA method using RAT BNP-32 kit (Phoenix Pharmaceutical Inc.). There was no statistically significant difference between mean BNP serum level in the stress group after the swimming period (0.81 +/- 0.14 ng/ml) as compared to the unstressed group of rats (0.8 +/- 0.08 ng/ml). After the swimming period mean body weight slightly decreased in the stress group in comparison with values before stress period (296.3 g vs. 272.8 g), but this difference was not statistically significant. The stress period had no influence on food intake in the stress rat group. The workload consisting of 40-minutes long swimming session is not sufficient to provoke BNP release from myocardium in rats.

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...

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...

Pineal thyroid relationship in psychic stress

International Nuclear Information System (INIS)

Singh, P.N.; Prasad, G.C.; Udupa, K.N.

1981-01-01

Pineal hormone and thyroid functions, were studied simultaneously in rats after the induction of acute psychic stress as well as exogenous administration of melatonin, thyroxine and also after thyroidectomy. A gradual increase in 131 I uptake, serum PBI and melatonin levels were observed in blood, reaching maximum on 8th day of psychic stress. Melatonin administration resulted in hypothyroidism whereas thyroxine increased the activity of pineal qland. Thyroidectomy revealed a gradual decrease in melatonin content of pineal gland whereas supplementation with thyroxine resulted in a melatonin content similar to that observed in sham operated (control) group. (author)

Long-term vegetarians have low oxidative stress, body fat, and cholesterol levels.

Science.gov (United States)

Kim, Mi Kyung; Cho, Sang Woon; Park, Yoo Kyoung

2012-04-01

Excessive oxidative stress and abnormal blood lipids may cause chronic diseases. This risk can be reduced by consuming an antioxidant- and fiber-rich vegetarian diet. We compared biomarkers of oxidative stress, antioxidant capacity, and lipid profiles of sex- and age-matched long-term vegetarians and omnivores in Korea. Forty-five vegetarians (23 men and 22 women; mean age, 49.5 ± 5.3 years), who had maintained a vegetarian diet for a minimum of 15 years, and 30 omnivores (15 men and 15 women; mean age, 48.9 ± 3.6 years) participated in this study. Their 1-day, 24-h recall, and 2-day dietary records were analyzed. Oxidative stress was measured by the levels of diacron reactive oxygen metabolites (d-ROM). Antioxidant status was determined by the biological antioxidant potential (BAP) and levels of endogenous antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. We observed that vegetarians had a significantly lower body fat percentage (21.6 ± 6.4%) than that of omnivores (25.4 ± 4.6%; P vegetarians than those in omnivores (331.82 ± 77.96 and 375.80 ± 67.26 Carratelli units; P vegetarians and omnivores were 173.73 ± 31.42 mg/dL and 193.17 ± 37.89 mg/dL, respectively (P vegetarians and omnivores, respectively, indicating that vegetarians had significantly lower lipid levels. Thus, oxidative stress, body fat, and cholesterol levels were lower in long-term vegetarians than those in omnivores.

The Red Sea during the Last Glacial Maximum: implications for sea level reconstructions

Science.gov (United States)

Gildor, H.; Biton, E.; Peltier, W. R.

2006-12-01

The Red Sea (RS) is a semi-enclosed basin connected to the Indian Ocean via a narrow and shallow strait, and surrounded by arid areas which exhibits high sensitivity to atmospheric changes and sea level reduction. We have used the MIT GCM to investigate the changes in the hydrography and circulation in the RS in response to reduced sea level, variability in the Indian monsoons, and changes in atmospheric temperature and humidity that occurred during the Last Glacial Maximum (LGM). The model results show high sensitivity to sea level reduction especially in the salinity field (increasing with the reduction in sea level) together with a mild atmospheric impact. Sea level reduction decreases the stratification, increases subsurface temperatures, and alters the circulation pattern at the Strait of Bab el Mandab, which experiences a transition from submaximal flow to maximal flow. The reduction in sea level at LGM alters the location of deep water formation which shifts to an open sea convective site in the northern part of the RS compared to present day situation in which deep water is formed from the Gulf of Suez outflow. Our main result based on both the GCM and on a simple hydraulic control model which takes into account mixing process at the Strait of Bab El Mandeb, is that sea level was reduced by only ~100 m in the Bab El Mandeb region during the LGM, i.e. the water depth at the Hanish sill (the shallowest part in the Strait Bab el Mandab) was around 34 m. This result agrees with the recent reconstruction of the LGM low stand of the sea in this region based upon the ICE-5G (VM2) model of Peltier (2004).

Maximum flood hazard assessment for OPG's deep geologic repository for low and intermediate level waste

International Nuclear Information System (INIS)

Nimmrichter, P.; McClintock, J.; Peng, J.; Leung, H.

2011-01-01

Ontario Power Generation (OPG) has entered a process to seek Environmental Assessment and licensing approvals to construct a Deep Geologic Repository (DGR) for Low and Intermediate Level Radioactive Waste (L&ILW) near the existing Western Waste Management Facility (WWMF) at the Bruce nuclear site in the Municipality of Kincardine, Ontario. In support of the design of the proposed DGR project, maximum flood stages were estimated for potential flood hazard risks associated with coastal, riverine and direct precipitation flooding. The estimation of lake/coastal flooding for the Bruce nuclear site considered potential extreme water levels in Lake Huron, storm surge and seiche, wind waves, and tsunamis. The riverine flood hazard assessment considered the Probable Maximum Flood (PMF) within the local watersheds, and within local drainage areas that will be directly impacted by the site development. A series of hydraulic models were developed, based on DGR project site grading and ditching, to assess the impact of a Probable Maximum Precipitation (PMP) occurring directly at the DGR site. Overall, this flood assessment concluded there is no potential for lake or riverine based flooding and the DGR area is not affected by tsunamis. However, it was also concluded from the results of this analysis that the PMF in proximity to the critical DGR operational areas and infrastructure would be higher than the proposed elevation of the entrance to the underground works. This paper provides an overview of the assessment of potential flood hazard risks associated with coastal, riverine and direct precipitation flooding that was completed for the DGR development. (author)

PERSONALITY TRAITS AND STRESS LEVELS AMONG SENIOR DENTAL STUDENTS: EVIDENCE FROM MALAYSIA AND SINGAPORE.

Science.gov (United States)

Yusof, Zamros Y M; Hassan, Wan Nurazreena Wan; Razak, Ishak A; Hashim, Siti Marini N; Tahir, Mohd Khairul A M; Keng, Siong Beng

2016-11-01

This study aimed to evaluate the association between dental students’ personality traits and stress levels in relation to dental education programs among senior dental students in University Malaya (UM) in Malaysia and National University of Singapore (NUS). A cross-sectional survey using a self-administered questionnaire was conducted on UM and NUS senior dental students. The questionnaire comprised items on demographic background, the Big Five Inventory Personality Traits (BFIPT) test and a modified Dental Environment Stress (DES) scale. Rasch analysis was used to convert raw data to interval scores. Analyses were done by t-test, Pearson correlation, and Hierarchical regression statistics. The response rate was 100% (UM=132, NUS=76). Personality trait Agreeableness (mean=0.30) was significantly more prevalent among UM than NUS students (mean=0.15, p=0.016). In NUS, Neuroticism (mean=0.36) was significantly more prevalent than in UM (mean=0.14, p=0.002). The DES mean score was higher among NUS (mean=0.23) than UM students (mean=0.07). In UM, Neuroticism was significantly correlated with stress levels (r=0.338, ppersonality traits. The correlation was strongest for personality trait Neuroticism in both schools. Hierarchical regression analysis showed that gender and Neuroticism were significant predictors for students’ stress levels (ppersonality trait were significant predictors for stress levels among selected groups of dental students in Southeast Asia. Information on students’ personality may be useful in new students’ intake, stress management counseling and future program reviews.

Effect of Different Levels of Sodium Chloride on Germination Characteristics of 20 Cultivars of Bread and Durum Wheat20 Cultivars of Bread and Durum Wheat

Directory of Open Access Journals (Sweden)

E Bijanzadeh

2011-01-01

Full Text Available Abstract Salt stress is a major stress influencing wheat seedling establishment. A laboratory experiment was conducted to evaluate the response of 20 cultivars of wheat to two levels of salinity (8 and 16 dS/m NaCl, at the College of Agriculture, Shiraz University, Shiraz, Iran in 2008. Maximum root length was obtained in Dabira (5.73 mm at 16dS/m salinity level. In control, durum wheat cultivars including D81-17, Yavaros, D82-16, D79-15 and Taro3 had the maximum root length compared to bread wheat, however, with increasing salinity level to 16dS/m, minimum root length was observed in D82-16 (0.3 mm. In all cultivars, with increasing salinity level, shoot length was decreased and minimum shoot length was observed in D82-16 and D79-15. Under control conditions, Taro 3 cultivar had maximum seedling dry weight (108.6 mm, however, at 8 and 16 dS/m salinity levels, seedling dry weight of this cultivar was decreased to 92.33 and 78.43 mg, respectively. All seeds (100% were germinated in D82-16, Taro3, Bolani Cross, and Chamran cultivars under 16 dS/m but in Marvdasht cultivar, seed germination percentage under 8 and 16 dS/m reached to 65 and 50%, respectively. Shiraz (10.8 seeds/day, Adl Cross(10 seeds/day, and Bolani Cross (9.1 seeds/day had maximum germination rate under 16 dS/m salinity level. Differences among wheat cultivars also found in germination stress index (germination rate under stress divided by germination rate under control and Shiraz, Adl Cross and Bolani Cross had maximum germination stress index, while Yavaros and D82-16 had minimum germination stress index. Furthermore, with increasing salinity level, different responses were observed among wheat cultivars in root and shoot length, germination rate and germination stress index which demonstrated the genetic diversity among wheat cultivars. It appeared that durum wheat cultivars, compared to bread wheat cultivars, had lower germination stress index and germination rate. Among what

Unconscious fearful priming followed by a psychosocial stress test results in higher cortisol levels.

Science.gov (United States)

Hänsel, Alexander; von Känel, Roland

2013-10-01

Human perception of stress includes an automatic pathway that processes subliminal presented stimuli below the threshold of conscious awareness. Subliminal stimuli can therefore activate the physiologic stress system. Unconscious emotional signals were shown to significantly moderate reactions and responses to subsequent stimuli, an effect called 'priming'. We hypothesized that subliminal presentation of a fearful signal during the Stroop task compared with an emotionally neutral one will prime stress reactivity in a subsequently applied psychosocial stress task, thereby yielding a significant increase in salivary cortisol. Half of 36 participants were repeatedly presented either a fearful face or a neutral one. After this, all underwent a psychosocial stress task. The fearful group showed a significant increase in cortisol levels (p = 0.022). This change was not affected by sex, age and body mass index, and it also did not change when taking resting cortisol levels into account. Post-hoc analyses showed that the increase in cortisol in the fearful group started immediately after the psychosocial stress test. Hence, subliminal exposure to a fearful signal in combination with the Stroop and followed by a psychosocial stress test leads to an increase in stress reactivity. Copyright © 2012 John Wiley & Sons, Ltd.

Survey of career satisfaction, lifestyle, and stress levels among pharmacy school faculty.

Science.gov (United States)

Lindfelt, Tristan A; Ip, Eric J; Barnett, Mitchell J

2015-09-15

U.S. pharmacy school faculty were surveyed to assess their career satisfaction, lifestyle, and stress levels. A 48-item survey, administered through Qualtrics (Provo, UT), was sent to current members of the American Association of Colleges of Pharmacy and included questions regarding respondents' academic institution and appointment status; lifestyle traits; career satisfaction; work-life balance; neurologic and psychiatric diagnoses; use of illicit drugs, alcohol, and tobacco; and stress levels. of the 4787 faculty invited to participate in the survey, 811 usable surveys were collected (16.9% response rate). Nearly all respondents (95.0%) reported working 40 or more hours per week. The majority had an average daily one-way commute of less than 30 minutes (64.2%), slept 5.5-7.5 hours per night (74.8%), and exercised for no more than 120 minutes per week (61.8%). A majority of respondents (63.7%) reported being very or extremely satisfied with their current position in academia. Only 36.9% reported being very or extremely satisfied with their work-life balance. Mean perceived stress scores were near those found in the general adult population. Although most respondents reported seeing a primary care provider and dentist annually, other findings regarding preventive health measures were not as encouraging. A survey of pharmacy faculty in the United States revealed high levels of job satisfaction among respondents, but lower levels of satisfaction with work-life balance and comparable levels of stress to the general population were found. Administrators and stakeholders should explore options to improve lifestyle factors to decrease potential burnout among faculty. Copyright © 2015 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Levels of salivary stress markers in patients with anxiety about halitosis.

Science.gov (United States)

Fukui, Makoto; Hinode, Daisuke; Yokoyama, Masaaki; Yoshioka, Masami; Kataoka, Kosuke; Ito, Hiro-O

2010-11-01

To investigate the relationship between salivary stress markers and mental stress states in patients complaining of oral malodour. The utility of the salivary stress markers in assessment of mental conditions of those patients was also investigated. The study population included 74 patients, aged 20-59 years, who complained of oral malodour and were referred to the Breath Odor Clinic at Tokushima University Hospital. Patients were classified into two groups, genuine halitosis (GH) and psychosomatic halitosis (PH), according to the results of organoleptic rating measurement. All patients were subjected to examination by the Cornell Medical Index (CMI) Health Questionnaire. Resting saliva was collected and levels of salivary IgA, cortisol and chromogranin A were determined by ELISA. Twenty-three volunteers not complaining of halitosis were included as the control group. Kruskal-Wallis test and Mann-Whitney's U-test were used for statistical analysis. A significant increase was observed in the concentrations of salivary cortisol in the PH group as compared with GH and control groups (psalivary cortisol concentrations were found in CMI scale III and IV (tendency towards neurosis) than in scale I and II (normal) (psalivary cortisol reflects a status of chronic stress condition, psychosomatic halitosis might be closely related to this state of chronic stress. Determination of cortisol levels in saliva may provide useful information for evaluating the mental status of patients complaining of halitosis. Copyright © 2010 Elsevier Ltd. All rights reserved.

The application of a Grey Markov Model to forecasting annual maximum water levels at hydrological stations

Science.gov (United States)

Dong, Sheng; Chi, Kun; Zhang, Qiyi; Zhang, Xiangdong

2012-03-01

Compared with traditional real-time forecasting, this paper proposes a Grey Markov Model (GMM) to forecast the maximum water levels at hydrological stations in the estuary area. The GMM combines the Grey System and Markov theory into a higher precision model. The GMM takes advantage of the Grey System to predict the trend values and uses the Markov theory to forecast fluctuation values, and thus gives forecast results involving two aspects of information. The procedure for forecasting annul maximum water levels with the GMM contains five main steps: 1) establish the GM (1, 1) model based on the data series; 2) estimate the trend values; 3) establish a Markov Model based on relative error series; 4) modify the relative errors caused in step 2, and then obtain the relative errors of the second order estimation; 5) compare the results with measured data and estimate the accuracy. The historical water level records (from 1960 to 1992) at Yuqiao Hydrological Station in the estuary area of the Haihe River near Tianjin, China are utilized to calibrate and verify the proposed model according to the above steps. Every 25 years' data are regarded as a hydro-sequence. Eight groups of simulated results show reasonable agreement between the predicted values and the measured data. The GMM is also applied to the 10 other hydrological stations in the same estuary. The forecast results for all of the hydrological stations are good or acceptable. The feasibility and effectiveness of this new forecasting model have been proved in this paper.

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.

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.

Relationship between stress levels and the status of serum ...

African Journals Online (AJOL)

McRoy

2014-07-26

Jul 26, 2014 ... very useful in proper dealing with it. Thus ... of examination, mean serum vitamin A levels was found to be significantly lower before than after ... [2] Cognitive and emotional signs and symptoms ... found that endurance exercise and stress can increase ... and 7 female, ages between 22-30 years) served as ...

New approach for monitoring fish stress: A novel enzyme-functionalized label-free immunosensor system for detecting cortisol levels in fish.

Science.gov (United States)

Wu, Haiyun; Ohnuki, Hitoshi; Ota, Shirei; Murata, Masataka; Yoshiura, Yasutoshi; Endo, Hideaki

2017-07-15

Fishes display a wide variation in their physiological responses to stress, which is clearly evident in the plasma corticosteroid changes, chiefly cortisol levels in fish. As a well-known indicator of fish stress, a simple and rapid method for detecting cortisol changes especially sudden increases is desired. In this study, we describe an enzyme-functionalized label-free immunosensor system for detecting fish cortisol levels. Detection of cortisol using amperometry was achieved by immobilizing both anti-cortisol antibody (selective detection of cortisol) and glucose oxidase (signal amplification and non-toxic measurement) on an Au electrode surface with a self-assembled monolayer. This system is based on the maximum glucose oxidation output current change induced by the generation of a non-conductive antigen-antibody complex, which depends on the levels of cortisol in the sample. The immunosensor responded to cortisol levels with a linear decrease in the current in the range of 1.25-200ngml -1 (R=0.964). Since the dynamic range of the sensor can cover the normal range of plasma cortisol in fish, the samples obtained from the fish did not need to be diluted. Further, electrochemical measurement of one sample required only ~30min. The sensor system was applied to determine the cortisol levels in plasma sampled from Nile tilapia (Oreochromis niloticus), which were then compared with levels of the same samples determined using the conventional method (ELISA). Values determined using both methods were well correlated. These findings suggest that the proposed label-free immunosensor could be useful for rapid and convenient analysis of cortisol levels in fish without sample dilution. We also believe that the proposed system could be integrated in a miniaturized potentiostat for point-of-care cortisol detection and useful as a portable diagnostic in fish farms in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

Temperature and stress calculation for final disposal

International Nuclear Information System (INIS)

Tarandi, T.

1979-02-01

Temperature and stress distribution in and around the final storage facility has been calculated for three different arrangements of the tunnels: - 2 planes with 60 m vertical distance between them - 2 planes with 100 m distance and - 1 plane. The highest temperatures and stresses occur for the 2 plane alternative with distance 60 m between planes. The maximum compressive stress is in this case 24.0 MPa 140 years after the time of deposition, compared with 12.6 MPa in the 1 plane case. The maximum tensile stress exists at the surface and is in the 2 plane case 6.0 MPa 800 - 1,500 years after deposition, compared with 4.2 MPa for the 1 plane variant. An estimation of maximum tensile stresses between the tunnel planes yields a value of 1.5 MPa. The above-mentioned stresses are due to temperature distribution induced by the radioactive waste. To obtain the total stresses, initial stresses in the undisturbed rock, which vary according to location, are to be added to these stresses. (author)

Do levels of perceived stress increase with increasing age after age 65? A population-based study.

Science.gov (United States)

Osmanovic-Thunström, Almira; Mossello, Enrico; Åkerstedt, Torbjörn; Fratiglioni, Laura; Wang, Hui-Xin

2015-09-01

psychological and health-related stressors often occur in advanced ages, but little is known about perceived stress in adults aged 65 and over. This study aimed to test the hypothesis that levels of perceived stress increase with increasing age and to detect factors that may account for the association. a dementia-free cohort of 1,656 adults aged 66-97 years living at home or in institutions, participating in the Swedish National Aging and Care study, Kungsholmen (SNAC-K) was assessed for levels of perceived stress using the 10-item perceived stress scale (PSS). prevalence of high stress according to the top tertile of the population (PSS score 20+) was 7.8% in adults aged 81+ years, 7.5% in adults aged 72-78 and 6.2% in adults aged 66 years (P = 0.020). More women than men reported high stress, 8.3 versus 5.4% (P = 0.001). Levels of stress increased with increasing age (P = 0.001) in the linear regression model. This association remained after adjustment for demographic and psychosocial factors, but no longer was present after adjusting for health-related factors. health-related stress is highly prevalent in older adults and seems to play an important role in the association between levels of perceived stress and age in older adults. © The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Level set segmentation of medical images based on local region statistics and maximum a posteriori probability.

Science.gov (United States)

Cui, Wenchao; Wang, Yi; Lei, Tao; Fan, Yangyu; Feng, Yan

2013-01-01

This paper presents a variational level set method for simultaneous segmentation and bias field estimation of medical images with intensity inhomogeneity. In our model, the statistics of image intensities belonging to each different tissue in local regions are characterized by Gaussian distributions with different means and variances. According to maximum a posteriori probability (MAP) and Bayes' rule, we first derive a local objective function for image intensities in a neighborhood around each pixel. Then this local objective function is integrated with respect to the neighborhood center over the entire image domain to give a global criterion. In level set framework, this global criterion defines an energy in terms of the level set functions that represent a partition of the image domain and a bias field that accounts for the intensity inhomogeneity of the image. Therefore, image segmentation and bias field estimation are simultaneously achieved via a level set evolution process. Experimental results for synthetic and real images show desirable performances of our method.

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

Analysis of University Organizational Culture Perceptions and Demographic Variables as Predictors of Perceived Stress

Directory of Open Access Journals (Sweden)

Mustafa KESEN

2015-06-01

Full Text Available It has been seen that it is inevitable for individuals to be exposed to stress in their student lives as in their work lives. The aim of this study is to measure perceived stress levels of university students in the university organizational culture setting. To this end, it is investigated the relationship between perceived stress levels of university students and university organizational culture perceptions. By using questionnaire method it is measured that the perceptions of organizational culture in different stress levels and it is analyzed that the differences in students' perceived stress levels according to socio-demographic variables. The population of the study is comprised of randomly chosen 286 students who receive training at Bayburt University Faculty of Economics and Administrative Sciences. According to the results, it has been found that there is a significant difference between students' perceived stress and gender. While the students stating that they experience low level of stress give maximum points to the variable of adaptation to change, other students expressing that they are exposed high level of stress give minimum score to the variable of cooperation. Besides, it has been found that different demographic variables by various combinations have different effects on perceived stress and university organizational culture.

Are PTH levels related to oxidative stress and inflammation in chronic kidney disease patients on hemodialysis?

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Marcel Jaqueto

Full Text Available Abstract Introduction: Patients at end stage renal disease have higher levels of inflammation and oxidative stress than the general population. Many factors contribute to these issues, and the parathyroid hormone (PTH is also implicated. Objective: The study was conducted in order to assess the relationship between PTH levels and inflammation and oxidative stress in hemodialysis patients. Methods: Cross-sectional study with patients of two hemodialysis facilities in Londrina, Brazil. Patients with other conditions known to generate oxidative stress and inflammation were excluded. Blood levels of PTH and biochemical parameters of inflammation (interleukins 1 and 6, tumor necrosis factor-alpha and oxidative stress (total plasma antioxidant capacity, malonic dialdehyde, lipid hydroperoxidation, advanced oxidation protein products, quantification of nitric oxide metabolites, and 8-isoprostane were measured before a dialysis session. Then, we made correlation analyses between PTH levels - either as the continuous variable or categorized into tertiles-, and inflammatory and oxidative stress biomarkers. Results: PTH did not show any correlation with the tested inflammation and oxidative stress parameters, nor as continuous variable neither as categorical variable. Conclusion: In this descriptive study, the results suggest that the inflammation and oxidative stress of hemodialysis patients probably arise from mechanisms other than secondary hyperparathyroidism.

Relationships between Salivary Melatonin Levels, Quality of Sleep, and Stress in Young Japanese Females

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Yasuhiro Ito

2013-01-01

Full Text Available A decrease in the quality of sleep is believed to cause anxiety and worsen depression. Comparisons of salivary melatonin levels with different factors including quality of sleep, state and trait anxieties, and depression, were conducted to examine whether there is a relationship between melatonin, presumably associated with sleep, and psychological stress. The saliva of healthy young females was collected during the daytime and before they went to bed at night (when they were awake and resting in a sitting position, and salivary melatonin levels were measured. The quality of sleep was scored using the Pittsburgh Sleep Quality Index (PSQI–-a questionnaire method. State and trait anxieties, and depression were scored using other questionnaire methods: the State-Trait Anxiety Inventory (STAI and Self-Rating Depression Scale (SDS, respectively. The following findings were obtained: (1 Salivary melatonin levels measured during the daytime and before going to bed were higher in females with a high depression score, compared to those with a low score, and there was a correlation between the depression scores and salivary melatonin levels measured at night; and (2 salivary melatonin levels measured before going to bed at night (in a sitting position were higher in females with a high state anxiety score, suggesting a correlation between state anxiety scores and salivary melatonin levels during the night. Both depression and a sense of anxiety are forms of psychological stress. Therefore, it is assumed that, when a person is under psychological stress, the action of melatonin as a ligand on its receptor is reduced. Meaning psychological stress may induce oxidative stress in the body. On the other hand, no correlation was noted between the quality of sleep and salivary melatonin levels during the night, presumably because saliva was collected when the subjects were awake and sitting, rather than sleeping.

Stress-induced rise in serum anti-brain autoantibody levels in the rat.

Science.gov (United States)

Andrejević, S; Bukilica, M; Dimitrijević, M; Laban, O; Radulovic, J; Kovacevic-Jovanovic, V; Stanojevic, S; Vasiljevic, T; Marković, B M

1997-02-01

Sera from Wistar rats subjected to different stress procedures were tested by ELISA for the presence of autoantibodies with specificity for neuron-specific enolase (NSE) and S100 protein that are preferentially localized in neurons and glia, respectively. Autoantibodies were present in sera of animals before exposure to stress, and raised with age. Anti-NSE and anti-S100 autoantibody levels were increased one day after termination of restraint (2 hours daily, 10 days) and electric tail shock (80 shocks daily, 19 days), and in fifth and tenth week of overcrowding stress. Differences between stressed and control animals were not present one month following restraint and electric tail shock and in twentieth week of overcrowding.

Level of Perceived Stress Among Lectures in Nigerian Universities

Science.gov (United States)

Ofoegbu, Felicia; Nwadiani, Mon

2006-01-01

The purpose of the study was to provide empirical evidence on the level of stress among lecturers in Nigerian universities. On the whole eight universities were used for the study. A sample of 228 (123 male and 105 female) lecturers was selected according to the variables of age, sex, marital status, experience, domicile, areas of specialization,…

Levels of Stress among General Practitioners, Students and Specialists In Pediatric Dentistry during Dental Treatment.

Science.gov (United States)

Davidovich, E; Pessov, Y; Baniel, A; Ram, D

2015-01-01

To assess self-reported stress during the performance of different procedures in pediatric dentistry, according to the professional experience of the dentists. During the years 2010 to 2011, an anonymous survey was administered by means of an internet link, and by distribution at professional meetings of dentists . No statistically significant differences in stress were reported for maxilla and mandibular procedures. Placement of a rubber dam was rated as the most stressful procedure among dental students. For general practitioners and specialists, injection of local anesthesia to an anxious child was the most stressful procedure, regardless of age, sex, or years of professional experience. A negative correlation was found between years of experience and level of stress for all the procedures surveyed, but not for the use of nitrous oxide. No differences were found between male and female dentists in stress scores for any of the procedures. Higher rates of stress during operative procedures were reported among dental students than among experienced dentists. Anxiety of the pediatric patients, but not the location of the procedure: maxillary or mandibular, affected the dentists' reported level of stress.

The regulation of starch accumulation in Panicum maximum Jacq ...

African Journals Online (AJOL)

... decrease the starch level. These observations are discussed in relation to the photosynthetic characteristics of P. maximum. Keywords: accumulation; botany; carbon assimilation; co2 fixation; growth conditions; mesophyll; metabolites; nitrogen; nitrogen levels; nitrogen supply; panicum maximum; plant physiology; starch; ...

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

Inactivation of basolateral amygdala prevents chronic immobilization stress-induced memory impairment and associated changes in corticosterone levels.

Science.gov (United States)

Tripathi, Sunil Jamuna; Chakraborty, Suwarna; Srikumar, B N; Raju, T R; Shankaranarayana Rao, B S

2017-07-01

Chronic stress causes detrimental effects on various forms of learning and memory. The basolateral amygdala (BLA) not only plays a crucial role in mediating certain forms of memory, but also in the modulation of the effects of stress. Chronic immobilization stress (CIS) results in hypertrophy of the BLA, which is believed to be one of the underlying causes for stress' effects on learning. Thus, it is plausible that preventing the effects of CIS on amygdala would preclude its deleterious cognitive effects. Accordingly, in the first part, we evaluated the effect of excitotoxic lesion of the BLA on chronic stress-induced hippocampal-dependent spatial learning using a partially baited radial arm maze task. The BLA was ablated bilaterally using ibotenic acid prior to CIS. Chronically stressed rats showed impairment in spatial learning with decreased percentage correct choice and increased reference memory errors. Excitotoxic lesion of the BLA prevented the impairment in spatial learning and reference memory. In the retention test, lesion of the BLA was able to rescue the chronic stress-induced impairment. Interestingly, stress-induced enhanced plasma corticosterone levels were partially prevented by the lesion of BLA. These results motivated us to evaluate if the same effects can be observed with temporary inactivation of BLA, only during stress. We found that chronic stress-induced spatial learning deficits were also prevented by temporary inactivation of the BLA. Additionally, temporary inactivation of BLA partially precluded the stress-induced increase in plasma corticosterone levels. Thus, inactivation of BLA precludes stress-induced spatial learning deficits, and enhanced plasma corticosterone levels. It is speculated that BLA inactivation-induced reduction in corticosterone levels during stress, might be crucial in restoring spatial learning impairments. Our study provides evidence that amygdalar modulation during stress might be beneficial for strategic

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.

Oxidative stress and neurological disorders in relation to blood lead levels in children.

Science.gov (United States)

Ahamed, M; Fareed, Mohd; Kumar, A; Siddiqui, W A; Siddiqui, M K J

2008-01-01

Oxidative stress plays a pivotal role in the pathogenesis of neurological disorders. Free radical generation appears to be the mode of lead toxicity. We evaluated the effects of blood lead levels on oxidative stress parameters in children suffering from neurological disorders. Thirty children (aged 3-12 years) with neurological disorders (cerebral palsy [n = 12], seizures [n = 11], and encephalopathy [n = 7]) were recruited in the study group. Sixty healthy children (aged 3-12 years) from similar socio-economic environments and not suffering from any chronic disease were taken as the controls. Blood lead levels and oxidant/antioxidant status were determined. Mean blood lead level was significantly higher while delta-aminolevulinic acid dehydratase (delta-ALAD) activity, a biomarker for lead exposure, was significantly lower in the study group as compared to the control group (P children with neurological disorders. Lead-induced oxidative stress as an underlying mechanism for neurological diseases in children warranted further investigation.

Use of Maximum Likelihood-Mixed Models to select stable reference genes: a case of heat stress response in sheep

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Salces Judit

2011-08-01

Full Text Available Abstract Background Reference genes with stable expression are required to normalize expression differences of target genes in qPCR experiments. Several procedures and companion software have been proposed to find the most stable genes. Model based procedures are attractive because they provide a solid statistical framework. NormFinder, a widely used software, uses a model based method. The pairwise comparison procedure implemented in GeNorm is a simpler procedure but one of the most extensively used. In the present work a statistical approach based in Maximum Likelihood estimation under mixed models was tested and compared with NormFinder and geNorm softwares. Sixteen candidate genes were tested in whole blood samples from control and heat stressed sheep. Results A model including gene and treatment as fixed effects, sample (animal, gene by treatment, gene by sample and treatment by sample interactions as random effects with heteroskedastic residual variance in gene by treatment levels was selected using goodness of fit and predictive ability criteria among a variety of models. Mean Square Error obtained under the selected model was used as indicator of gene expression stability. Genes top and bottom ranked by the three approaches were similar; however, notable differences for the best pair of genes selected for each method and the remaining genes of the rankings were shown. Differences among the expression values of normalized targets for each statistical approach were also found. Conclusions Optimal statistical properties of Maximum Likelihood estimation joined to mixed model flexibility allow for more accurate estimation of expression stability of genes under many different situations. Accurate selection of reference genes has a direct impact over the normalized expression values of a given target gene. This may be critical when the aim of the study is to compare expression rate differences among samples under different environmental

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.

Stimulated bioluminescence by fluid shear stress associated with pipe flow

Energy Technology Data Exchange (ETDEWEB)

Cao Jing; Wang Jiangan; Wu Ronghua, E-mail: caojing981@126.com [Col. of Electronic Eng., Naval University of Engineering, Wuhan 430033 (China)

2011-01-01

Dinoflagellate can be stimulated bioluminescence by hydrodynamic agitation. Two typical dinoflagellate (Lingulodinium polyedrum and Pyrocystis noctiluca) was choosed to research stimulated bioluminescence. The bioluminescence intensity and shear stress intensity were measured using fully developed pipe flow. There is shear stress threshold to agitate organism bioluminescence. From these experiment, the response thresholds of the stimulated bioluminscence always occurred in laminar flows at a shear stress level of 0.6-3 dyn/cm{sup 2}. At the same time, the spectral characteristc of dinoflagellate was recorded, the wavelength of them is about 470nm, and the full width at half maximum is approximate 30nm.

The study of mechanical properties and reactive stresses in the i-Ni-Nb shape memory alloys

International Nuclear Information System (INIS)

Popov, N.N.; Sysoeva, T.I.; Lar'kin, V.F.; Vedernikova, I.I.; Prokoshkin, S.D.

2007-01-01

One investigated into the effect of the induced deformation value, rate and temperature, of the thermal treatment procedure and of the chemical composition on the mechanical properties and the development of the reactive stresses in Ti-Ni-Nb system shape memory alloys. One showed the effect of the material composition and of the deformation temperature on the mechanical features of the investigated alloys. One determined the temperature and deformation conditions ensuring the maximum level of the reactive stresses in the alloys. One revealed the dependence of the maximum reactive stress value on the austenite mechanical features, namely, on its yield limit. One chose Ti-Ni-Nb alloy compositions applicable in the pipeline thermomechanical connections [ru

Brief strategic therapy in first myocardial infarction patients with increased levels of stress: a randomized clinical trial.

Science.gov (United States)

Rakowska, Jadwiga Małgorzata

2015-01-01

Little is known about the impact of interventions targeting chronic stress levels on clinical outcomes among myocardial infarction (MI) patients with increased levels of stress. To examine the impact of the addition of brief strategic therapy (BST) to usual care (UC) on clinical outcomes in first MI patients with increased levels of stress. Eighty-one patients were randomly assigned to BST in conjunction with UC (medical treatment, risk factor information, and guidance on unhealthy behavior change) or to UC. The outcome measures were scores on the Perceived Stress Scale, reinfarction and cardiac mortality rates, and scores on the Health Survey. Measures were taken before, post-treatment, and at two follow-ups. Patients subjected to BST showed reduced perceived stress at post-treatment and maintained decreased levels at follow-ups. At 1-year follow-up, they had a lower rate of non-fatal reinfarction, and at 2.5-year follow-up, they had a lower rate of fatal reinfarction. Their mental and physical health was improved at post-treatment and this was sustained at follow-ups. The addition of BST to UC favorably influences the disease course after MI in patients with increased levels of stress.

Thermal stresses in long prisms by relaxation methods

International Nuclear Information System (INIS)

Cummins, J.D.

1959-07-01

A general method is presented for calculating the elastic thermal stresses in long prisms which are producing heat and are not solvable by simple analytical methods. The problem of an inverted lattice i.e. an hexagonal coolant passage surrounded by hexagonal fuel elements is considered and the temperature and principal thermal stress distributions evaluated for the particular case of 20% coolant. The maximum thermal stress for this type of fuel element is about the same as the maximum thermal stress in a cylindrical fuel element surrounded by a sea of coolant assuming the existence of the same maximum temperature drop and material properties. (author)

Thermal stresses in long prisms by relaxation methods

Energy Technology Data Exchange (ETDEWEB)

Cummins, J D [Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1959-07-15

A general method is presented for calculating the elastic thermal stresses in long prisms which are producing heat and are not solvable by simple analytical methods. The problem of an inverted lattice i.e. an hexagonal coolant passage surrounded by hexagonal fuel elements is considered and the temperature and principal thermal stress distributions evaluated for the particular case of 20% coolant. The maximum thermal stress for this type of fuel element is about the same as the maximum thermal stress in a cylindrical fuel element surrounded by a sea of coolant assuming the existence of the same maximum temperature drop and material properties. (author)

Maximum coherent superposition state achievement using a non-resonant pulse train in non-degenerate three-level atoms

International Nuclear Information System (INIS)

Deng, Li; Niu, Yueping; Jin, Luling; Gong, Shangqing

2010-01-01

The coherent superposition state of the lower two levels in non-degenerate three-level Λ atoms is investigated using the accumulative effects of non-resonant pulse trains when the repetition period is smaller than the decay time of the upper level. First, using a rectangular pulse train, the accumulative effects are re-examined in the non-resonant two-level atoms and the modified constructive accumulation equation is analytically given. The equation shows that the relative phase and the repetition period are important in the accumulative effect. Next, under the modified equation in the non-degenerate three-level Λ atoms, we show that besides the constructive accumulation effect, the use of the partial constructive accumulation effect can also achieve the steady state of the maximum coherent superposition state of the lower two levels and the latter condition is relatively easier to manipulate. The analysis is verified by numerical calculations. The influence of the external levels in such a case is also considered and we find that it can be avoided effectively. The above analysis is also applicable to pulse trains with arbitrary envelopes.

Influence of heat input and radius to pipe thickness ratio on the residual stresses in circumferential arc welded pipes of API X46 steels

International Nuclear Information System (INIS)

Hemmatzadeh, Majid; Moshayedi, Hessamoddin; Sattari-Far, Iradj

2017-01-01

The present work aims to study residual stresses caused by circumferentially welding of two similar API X46 steel pipes by means of finite element modeling. Considering the metallurgical phase transformations and through thermal-mechanical uncoupled analysis, the 3D modeling was carried out by SYSWELD software. Materialistic thermal and mechanical properties of all phases were defined in terms of temperature as well as phase transformation properties. Residual stress was measured through hole-drilling method. The obtained results were used to verify the finite element model. By means of full factorial experiment designing method, effects of heat input and radius to pipe thickness ratio on maximum values of hoop and axial residual stresses were investigated. The effect of each factor was studied in 3 levels and by 9 experiments. Results of statistical analysis revealed that increase in heat input and radius-thickness ratio would lead to higher values of maximum hoop and axial residual stresses. However, interactions of high level of heat input and a low level of radius-thickness ratio increased inter-pass temperature and consequently caused a sudden raise in maximum values of residual stresses. - Highlights: • A FEM model was developed to simulate welding considering phase transformations. • The obtained residual stresses were validated by experiments. • Effect of heat input and radius-to-thickness ratio on residual stress were investigated. • Increasing heat input for 100% caused increasing hoop and axial residual stress until 200%. • Interaction of high heat input and low R/t causes a sudden increase in axial residual stresses.

Abscisic Acid Accumulation by Roots of Xanthium strumarium L. and Lycopersicon esculentum Mill. in Relation to Water Stress.

Science.gov (United States)

Cornish, K; Zeevaart, J A

1985-11-01

Plants of Xanthium strumarium L. and Lycopersicon esculentum Mill. cv ;Rheinlands Ruhm' were grown in solution culture, and control and steam-girdled intact plants were stressed. Detached roots of both species were stressed to different extents in two ways: (a) either in warm air or, (b) in the osmoticum Aquacide III. The roots of both species produced and accumulated progressively more abscisic acid (ABA), the greater the stress inflicted by either method. ABA-glucose ester levels in Xanthium roots were not affected by water stress and were too low to be the source of the stress-induced ABA. The fact that ABA accumulated in detached roots and in roots of girdled plants proves that ABA was synthesized in the roots and not merely transported from the shoots.Maximum ABA accumulation in detached roots occurred after 60 to 70% loss of fresh weight. In Xanthium roots, ABA levels continued to increase for at least 11 hours, and no catabolism was apparent when stressed roots were immersed in water, although the roots did stop accumulating ABA. When osmotically stressed, Xanthium roots reached a maximum ABA level after 2 hours, but ABA continued to rise in the medium.Under optimal stress conditions, endogenous ABA levels increased 100 times over their prestress values in detached roots of Xanthium, and 15 times in Lycopersicon under nonoptimal stress, when endogenous ABA was expressed as concentrations based on tissue water content. These are much greater relative increases than observed in the leaves (15 times in Xanthium, 3 times in Lycopersicon), although the roots contain substantially less ABA than the leaves in all circumstances. The results suggest that the endogenous level of ABA in roots could rise appreciably prior to leaf wilt, and could modify the plant's water economy before the leaves become stressed.

Water stress, CO2 and photoperiod influence hormone levels in wheat

Science.gov (United States)

Nan, Rubin; Carman, John G.; Salisbury, Frank B.; Campbell, W. F. (Principal Investigator)

2002-01-01

'Super Dwarf' wheat (Triticum aestivum L.) plants have been grown from seed to maturity in the Mir space station where they were periodically exposed, because of microgravity and other constraints, to water deficit, waterlogging, high CO2 levels, and low light intensities. The plants produced many tillers, but none of them produced viable seed. Studies have been initiated to determine why the plants responded in these ways. In the present study, effects of the listed stresses on abscisic acid (ABA), indole-3-acetic acid (IAA) and isopentenyl adenosine ([9R]iP) levels in roots and leaves of plants grown under otherwise near optimal conditions on earth were measured. Hormones were extracted, purified by HPLC, and quantified by noncompetitive indirect ELISA. In response to water deficit, ABA levels increased in roots and leaves, IAA levels decreased in roots and leaves, and [9R]iP levels increased in leaves but decreased in roots. In response to waterlogging, ABA, IAA and [9R]iP levels briefly increased in roots and leaves and then decreased. When portions of the root system were exposed to waterlogging and/or water deficit, ABA levels in leaves increased while [9R]iP and IAA levels decreased. These responses were correlated with the percentage of the root system stressed. At a low photosynthetic photon flux (100 micromoles m-2 s-1), plants grown in continuous light had higher leaf ABA levels than plants grown using an 18 or 21 h photoperiod.

The Effects of a Maximal Power Training Cycle on the Strength, Maximum Power, Vertical Jump Height and Acceleration of High-Level 400-Meter Hurdlers

Science.gov (United States)

Balsalobre-Fernández, Carlos; Tejero-González, Carlos Mª; del Campo-Vecino, Juan; Alonso-Curiel, Dionisio

2013-01-01

The aim of this study was to determine the effects of a power training cycle on maximum strength, maximum power, vertical jump height and acceleration in seven high-level 400-meter hurdlers subjected to a specific training program twice a week for 10 weeks. Each training session consisted of five sets of eight jump-squats with the load at which each athlete produced his maximum power. The repetition maximum in the half squat position (RM), maximum power in the jump-squat (W), a squat jump (SJ), countermovement jump (CSJ), and a 30-meter sprint from a standing position were measured before and after the training program using an accelerometer, an infra-red platform and photo-cells. The results indicated the following statistically significant improvements: a 7.9% increase in RM (Z=−2.03, p=0.021, δc=0.39), a 2.3% improvement in SJ (Z=−1.69, p=0.045, δc=0.29), a 1.43% decrease in the 30-meter sprint (Z=−1.70, p=0.044, δc=0.12), and, where maximum power was produced, a change in the RM percentage from 56 to 62% (Z=−1.75, p=0.039, δc=0.54). As such, it can be concluded that strength training with a maximum power load is an effective means of increasing strength and acceleration in high-level hurdlers. PMID:23717361

Hydraulic fracturing rock stress measurement at Haestholmen, Finland

International Nuclear Information System (INIS)

Ljunggren, C.; Klasson, H.

1992-12-01

This report presents hydraulic fracturing measurements in two boreholes located on the Haestholmen island near Loviisa, Finland. The aim of the measurements was to provide stress data, forming input for the design of an underground facility for disposal of low- and medium-level waste as well as future plant decommissioning radioactive waste from the IVO reactor units situated on Haestholmen. The theoretical background to the hydrofracturing method is summarized, as is the equipment and experimental procedures used in the present case. All results obtained are presented and critically discussed. The final stress parameters presented are magnitudes and directions of the maximum and minimum horizontal stresses. Testing was successfully completed according to schedule in both boreholes.(orig.)

19 mm sized bileaflet valve prostheses' flow field investigated by bidimensional laser Doppler anemometry (part II: maximum turbulent shear stresses)

Science.gov (United States)

Barbaro, V; Grigioni, M; Daniele, C; D'Avenio, G; Boccanera, G

1997-11-01

The investigation of the flow field generated by cardiac valve prostheses is a necessary task to gain knowledge on the possible relationship between turbulence-derived stresses and the hemolytic and thrombogenic complications in patients after valve replacement. The study of turbulence flows downstream of cardiac prostheses, in literature, especially concerns large-sized prostheses with a variable flow regime from very low up to 6 L/min. The Food and Drug Administration draft guidance requires the study of the minimum prosthetic size at a high cardiac output to reach the maximum Reynolds number conditions. Within the framework of a national research project regarding the characterization of cardiovascular endoprostheses, an in-depth study of turbulence generated downstream of bileaflet cardiac valves is currently under way at the Laboratory of Biomedical Engineering of the Istituto Superiore di Sanita. Four models of 19 mm bileaflet valve prostheses were used: St Jude Medical HP, Edwards Tekna, Sorin Bicarbon, and CarboMedics. The prostheses were selected for the nominal Tissue Annulus Diameter as reported by manufacturers without any assessment of valve sizing method, and were mounted in aortic position. The aortic geometry was scaled for 19 mm prostheses using angiographic data. The turbulence-derived shear stresses were investigated very close to the valve (0.35 D0), using a bidimensional Laser Doppler anemometry system and applying the Principal Stress Analysis. Results concern typical turbulence quantities during a 50 ms window at peak flow in the systolic phase. Conclusions are drawn regarding the turbulence associated to valve design features, as well as the possible damage to blood constituents.

Optimization of the dissolved hydrogen level in PWR to mitigate stress corrosion cracking of nickel alloys. Bibliographic review, modelling and recommendations

International Nuclear Information System (INIS)

Labousse, M.; Deforge, D.; Gressier, F.; Taunier, S.; Le Calvar, M.

2012-09-01

Nickel based alloys Stress Corrosion Cracking (SCC) has been a major concern for the Nuclear Power Plants (NPP) utilities since more than 40 years. At EDF, this issue led to the replacement of all upper vessel heads and of most of the steam generators with Alloy 600 MA tubes. Under the scope of plant lifetime extension, there is some concerns about the behaviour of Bottom Mounted Instrumentation Nozzles (BMI) made of Alloy 600 welded with Alloy 182 and a few vessel dissimilar metal welds made of Alloy 82, for only three 1450 MWe plants. It is considered for long that Primary Water Stress Corrosion Cracking (PWSCC) is influenced by the dissolved hydrogen (DH) level in primary coolant. Now, the whole community clearly understands that there is a hydrogen level corresponding to a maximum in terms of SCC susceptibility. Many experimental studies were done worldwide to optimize the hydrogen level in primary water during power operation, both in terms of SCC initiation and propagation. From these studies, most of American plants decided to increase the dissolved hydrogen level in order to mitigate crack propagation. Conversely, in Japan, based on crack initiation data, it is thought that drastically decreasing the hydrogen content would rather be beneficial. In order to consolidate EDF position, a review of laboratory tests data was made. Studies on the influence of hydrogen on nickel alloys 600 and 182 PWSCC were compiled and rationalized. Data were collapsed using a classical Gaussian model, such as initially proposed by Morton et al. An alternative model based on more phenomenological considerations was also proposed. Both models lead to similar results. The maximum susceptibility to SCC cracking appears to be rather consistent with the Ni/NiO transition, which was not taken as an initial hypothesis. Regarding crack initiation, an inverse Gaussian model was proposed. Based on the current hydrogen concentration range during power operation and considering components

Stress Level of Measurement of Public Employees A Research on Public Officials in Eskisehir

OpenAIRE

Hüseyin GÜRBÜZ; Rüveyda DOĞAN; Elif GÖRMÜŞ; Gamze Pelin TOKYAY; Dilara ÖZTEKİN; Gökhan ENGİZ

2014-01-01

Stress emerges as a concept which negatively affects the efficiency and the productivity of an individual. In addition to the negative and productivity lessening effects of stress, some researchers cited various positive effects of it. A stress level that affects an increase in productivity and that doesn’t cause a deterioration of health is accepted as a positive one and the studies about stress in work life mostly focus on the productivity of the employees.. This study was focused on the fa...

[Appraisal of occupational stress in different gender, age, work duration, educational level and marital status groups].

Science.gov (United States)

Yang, Xin-Wei; Wang, Zhi-Ming; Jin, Tai-Yi

2006-05-01

This study was conducted to assess occupational stress in different gender, age, work duration, educational level and marital status group. A test of occupational stress in different gender, age, work duration, educational level and marital status group, was carried out with revised occupational stress inventory (OSI-R) for 4278 participants. The results of gender show that there are heavier occupational role, stronger interpersonal and physical strain in male than that in female, and the differences are statistically significant (P 0.05). The occupational stress so as to improve the work ability of different groups. Different measure should be taken to reduce the occupational stress so as to improve the work ability of different groups.

Glacial rebound and crustal stress in Finland

International Nuclear Information System (INIS)

Lambeck, K.; Purcell, A.

2003-11-01

The last ice age of Fennoscandinavia continues to have geological repercussions across Finland despite the last ice having retreated almost 10,000 years ago: land uplift, shoreline retreat, and the stress state of the crust continues to evolve. This report focusses on the glacial rebound signals for Finland and the Gulf of Bothnia and explores the consequences of the ongoing deformation. The rebound signals include the geological evidence as well as instrumental observations: the tide gauge and lake-level measurements of the past century, the changes in geodetic levels recorded in the repeat levelling surveys of the region and the direct measurement of crustal deformation (radial and horizontal) using high-precision space-geodesy measurements. These signals provide constraints on the Earth's rheology, its elasticity and viscosity, and the glacial history of the region. Once observationally constrained, the rebound models are used to predict both the ongoing evolution of shorelines and the changing state of stress within the crust. This report covers: (i) A review of glacial rebound modelling for Scandinavia (Sections 2 and 3). (ii) Review of observational evidence relating to sea-level change and crustal rebound (Section 4). (iii) New earth and ice-sheet model results from the inversion of the geological evidence for sea-level change, including models of shoreline evolution (Sections 5 and 6). (iv) Earth-model results from the inversion of the geodetic evidence for sea-level change (Section 7). (v) Development of crustal stress models for past and present stress states (Section 8). (vi) Conclusions and recommendations (Section 9). Specific conclusions reached pertain to: (i) Thickness of ice cover over Scandinavia since the Last Glacial Maximum, particularly for the Lateglacial period. (ii) Sea-level change and shoreline evolution for the Baltic area since the time the region became ice-free for the last time. (iii) The predicted rates of present-day crustal

Involvement of α(2)-adrenergic receptor in the regulation of the blood glucose level induced by immobilization stress.

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Kang, Yu-Jung; Sim, Yun-Beom; Park, Soo-Hyun; Sharma, Naveen; Suh, Hong-Won

2015-01-01

The blood glucose profiles were characterized after mice were forced into immobilization stress with various exposure durations. The blood glucose level was significantly enhanced by immobilization stress for 30 min or 1 h, respectively. On the other hand, the blood glucose level was not affected in the groups which were forced into immobilization stress for 2 or 4 h. We further examined the effect of yohimbine (an α2-adrenergic receptor antagonist) administered systemically or centrally in the immobilization stress model. Mice were pretreated intraperitoneally (i.p.; from 0.5 to 5 mg/kg), intracerebroventricularly (i.c.v.; from 1 to 10 µg/5 µl), or intrathecally (i.t.; from 1 to 10 µg/5 µl) with yohimbine for 10 min and then, forced into immobilization stress for 30 min. The blood glucose level was measured right after immobilization stress. We found that up-regulation of the blood glucose level induced by immobilization stress was abolished by i.p. pretreatment with yohimbine. And the immobilization stress-induced blood glucose level was not inhibited by i.c.v. or i.t. pretreatment with yohimbine at a lower dose (1 µg/5 µl). However, immobilization stress-induced blood glucose level was significantly inhibited by i.c.v. or i.t. pretreatment with yohimbine at higher doses (5 and 10 µg/5 µl). In addition, the i.p. (5 mg/kg), i.c.v. (10 µg/5 µl), or i.t. (10 µg/5 µl) pretreatment with yohimbine reduced hypothalamic glucose transporter 4 expression. The involvement of α2-adrenergic receptor in regulation of immobilization stress- induced blood glucose level was further confirmed by the i.p, i.c.v, or i.t pretreatment with idazoxan, another specific α2-adrenergic receptor antagonist. Finally, i.p., i.c.v., or i.t. pretreatment with yohimbine attenuated the blood glucose level in D-glucose-fed model. We suggest that α2-adrenergic receptors located at the peripheral, the brain and the spinal cord play important roles in the up

A study on level of physical activity, depression, anxiety and stress symptoms among adolescents.

Science.gov (United States)

Tajik, Esra; Abd Latiff, Latiffah; Adznam, Siti N; Awang, Hamidin; Yit Siew, Chin; Abu Bakar, Azrin S

2017-10-01

Inadequate physical activity has adverse health consequences among adolescents. Mental health problem can be developed by lack of physical activity however it is controversial. The current study aimed to examine the association between level of physical activity with depression, anxiety and stress symptoms among adolescents. A representative sample of 1747 adolescents (13-14 years) was randomly selected from 6 schools in a south part of Malaysia. Respondents were asked to fill consent form, and questionnaires including Depression Anxiety and Stress Scale-21 and Physical Activity Questionnaire for Adolescents. Majority of respondents (71.9%) was Malay and more than half of the adolescents had low physical activity. About 40% had depression symptoms, followed by anxiety symptoms (65.9%) and stress symptoms (38.5%). Level of physical activity was significantly associated with gender, anxiety and stress (P<0.001). There were no associations with race, religion and depression symptom. This study provides some evidence among school-going adolescents related to anxiety and stress symptoms and low physical activities. Further studies are needed to show the protection effects of higher physical activity for depression, anxiety and stress symptoms in adolescents.

The calculation of maximum permissible exposure levels for laser radiation

International Nuclear Information System (INIS)

Tozer, B.A.

1979-01-01

The maximum permissible exposure data of the revised standard BS 4803 are presented as a set of decision charts which ensure that the user automatically takes into account such details as pulse length and pulse pattern, limiting angular subtense, combinations of multiple wavelength and/or multiple pulse lengths, etc. The two decision charts given are for the calculation of radiation hazards to skin and eye respectively. (author)

Local and systemic oxidative stress and glucocorticoid receptor levels in chronic obstructive pulmonary disease patients

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Zeng, Mian; Li, Yue; Jiang, Yujie; Lu, Guifang; Huang, Xiaomei; Guan, Kaipan

2013-01-01

BACKGROUND: Previous studies have indicated that oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). OBJECTIVES: To study local and systemic oxidative stress status in COPD patients, and to clarify the relationship between local and systemic oxidative stress. METHODS: Lipid peroxide malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and GSH peroxidase (GSH-PX) levels in induced sputum and plasma, as well as glucocorticoid receptor (GR) levels in peripheral blood leukocytes were examined in 43 acute exacerbation of COPD patients (group A), 35 patients with stable COPD (group B) and 28 healthy controls (14 smokers [group C]; 14 nonsmokers [group D]). RESULTS: MDA levels in induced sputum and plasma decreased progressively in groups A to D, with significant differences between any two groups (P<0.001). GSH, SOD and GSH-PX levels in both induced sputum and plasma increased progressively in groups A to D, with significant differences between any two groups (P<0.001). GR levels in peripheral blood leukocytes decreased progressively in groups D to A (all comparisons P<0.001). Pearson analysis revealed strong correlations between MDA, GSH, SOD and GSH-PX levels in plasma and induced sputum. The activity of SOD in plasma and sputum were both positively correlated with GR levels (partial correlation coefficients 0.522 and 0.574, respectively [P<0.001]). CONCLUSIONS: Oxidative stress levels were elevated in COPD patients. There was a correlation between local and systemic oxidative status in COPD, and between decreased SOD activity and decreased GR levels in COPD patients. PMID:23457673

Abscisic Acid Accumulation by Roots of Xanthium strumarium L. and Lycopersicon esculentum Mill. in Relation to Water Stress 1

Science.gov (United States)

Cornish, Katrina; Zeevaart, Jan A. D.

1985-01-01

Plants of Xanthium strumarium L. and Lycopersicon esculentum Mill. cv `Rheinlands Ruhm' were grown in solution culture, and control and steam-girdled intact plants were stressed. Detached roots of both species were stressed to different extents in two ways: (a) either in warm air or, (b) in the osmoticum Aquacide III. The roots of both species produced and accumulated progressively more abscisic acid (ABA), the greater the stress inflicted by either method. ABA-glucose ester levels in Xanthium roots were not affected by water stress and were too low to be the source of the stress-induced ABA. The fact that ABA accumulated in detached roots and in roots of girdled plants proves that ABA was synthesized in the roots and not merely transported from the shoots. Maximum ABA accumulation in detached roots occurred after 60 to 70% loss of fresh weight. In Xanthium roots, ABA levels continued to increase for at least 11 hours, and no catabolism was apparent when stressed roots were immersed in water, although the roots did stop accumulating ABA. When osmotically stressed, Xanthium roots reached a maximum ABA level after 2 hours, but ABA continued to rise in the medium. Under optimal stress conditions, endogenous ABA levels increased 100 times over their prestress values in detached roots of Xanthium, and 15 times in Lycopersicon under nonoptimal stress, when endogenous ABA was expressed as concentrations based on tissue water content. These are much greater relative increases than observed in the leaves (15 times in Xanthium, 3 times in Lycopersicon), although the roots contain substantially less ABA than the leaves in all circumstances. The results suggest that the endogenous level of ABA in roots could rise appreciably prior to leaf wilt, and could modify the plant's water economy before the leaves become stressed. PMID:16664467

Perceived stress, depressive symptoms, and suicidal ideation in undergraduate women with varying levels of mindfulness.

Science.gov (United States)

Anastasiades, Maria H; Kapoor, Shweta; Wootten, Jennifer; Lamis, Dorian A

2017-02-01

Research has demonstrated that perceived stress and depression are risk factors for suicidal ideation in young adults, particularly women attending college. Female undergraduate students (N = 928) were administered measures assessing their levels of stress, depressive symptoms, suicidal thoughts, and mindfulness. A moderated-mediation analysis was conducted to examine the complex associations among these variables. Results indicated that mindfulness moderated the mediated effect of depressive symptoms on perceived stress and suicidal ideation. Specifically, the indirect effect was stronger in college women with lower levels of mindfulness as compared to those students who reported higher mindfulness. Thus, teaching mindfulness techniques on college campuses may be an important strategy for preventing suicide, especially among young adult women experiencing stress and depressive symptoms.

Systems study of the feasibility of high-level nuclear waste fractionation for thermal stress control in a geologic repository: appendices

International Nuclear Information System (INIS)

McKee, R.W.; Elder, H.K.; McCallum, R.F.; Silviera, D.J.; Swanson, J.L.; Wiles, L.E.

1983-06-01

This study assesses the benefits and costs of fractionating the cesium and strontium (Cs/Sr) components in commercial high-level waste (HLW) to a separate waste stream for the purpose of reducing geologic-repository thermal stresses in the region of the HLW. The major conclusion is that the Cs/Sr fractionation concept offers the prospect of a substantial total system cost advantage for HLW disposal if reduced HLW package temperatures in a basalt repository are desired. However there is no cost advantage if currently designated maximum design temperatures are acceptable. Aging the HLW for 50 to 100 years can accomplish similar results at equivalent or lower costs. Volume II contains appendices for: (1) thermal analysis supplement; (2) fractionation process experimental results supplement; (3) cost analysis supplement; and (4) radiological risk analysis supplement

Chronic family stress moderates the association between a TOMM40 variant and triglyceride levels in two independent Caucasian samples

DEFF Research Database (Denmark)

Jiang, Rong; Brummett, Beverly H; Hauser, Elizabeth R

2013-01-01

independent Caucasian samples (242 U.S. women and men; 466 Danish men) testing the hypothesis that chronic family stress also moderates the association between rs157580 and triglyceride levels. The interaction of rs157580 and family stress in predicting triglyceride levels was statistically significant...... in the U.S. sample (p=0.004) and marginally significant (p=0.075) in the Danish sample. The G allele of rs157580 was associated with increased triglyceride levels among family stressed cases in both samples compared with A/A cases, but not among controls. Chronic family stress moderates the association......TOMM40 SNP rs157580 has been associated with triglyceride levels in genome-wide association studies (GWAS). Chronic caregiving stress moderates the association between triglyceride levels and a nearby SNP rs439401 that is associated with triglyceride levels in GWAS. Here, we report data from two...

County-Level Climate Uncertainty for Risk Assessments: Volume 18 Appendix Q - Historical Maximum Near-Surface Wind Speed.

Energy Technology Data Exchange (ETDEWEB)

Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

2017-06-01

This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconom ic impacts. The full report is contained in 27 volumes.

County-Level Climate Uncertainty for Risk Assessments: Volume 4 Appendix C - Historical Maximum Near-Surface Air Temperature.

Energy Technology Data Exchange (ETDEWEB)

Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

2017-06-01

This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

[The effects of hatha yoga exercises on stress and anxiety levels in mastectomized women].

Science.gov (United States)

Bernardi, Marina Lima Daleprane; Amorim, Maria Helena Costa; Zandonade, Eliana; Santaella, Danilo Forghieri; Barbosa, Juliana de Assis Novais

2013-12-01

This article seeks to evaluate the effects of hatha yoga on stress and anxiety levels in mastectomized women. It also investigates the relationship between these levels with the following variables: age; marital status; religion; instruction; profession; smoke addiction; elitism; staging of the disease; and treatment phase. This involved controlled random clinical trial sampling of 45 mastectomized women treated at the Ilza Bianco outpatient service of Santa Rita de Cássia Hospital in the Brazilian state of Espírito Santo from March to November 2010. The experimental group participated in 6 individually-applied sessions with incentive for ongoing home practice and was re-evaluated after the period, whereas the control group was re-evaluated after a proportional period. For the study of the variables, the interview and recording on a form technique was used, along with the Anxiety Trait and State Test, and the Stress Symptoms and Signs Test. For statistical treatment, the Statistical Pack for Social Sciences was used. The data are statistically significant and have shown that hatha yoga exercises decrease stress and anxiety in the experimental group. No connection between confounding variables and anxiety and stress levels was found.

Despite higher glucocorticoid levels and stress responses in female rats, both sexes exhibit similar stress-induced changes in hippocampal neurogenesis.

Science.gov (United States)

Hulshof, Henriëtte J; Novati, Arianna; Luiten, Paul G M; den Boer, Johan A; Meerlo, Peter

2012-10-01

Sex differences in stress reactivity may be one of the factors underlying the increased sensitivity for the development of psychopathologies in women. Particularly, an increased hypothalamic-pituitary-adrenal (HPA) axis reactivity in females may exacerbate stress-induced changes in neuronal plasticity and neurogenesis, which in turn may contribute to an increased sensitivity to psychopathology. The main aim of the present study was to examine male-female differences in stress-induced changes in different aspects of hippocampal neurogenesis, i.e. cell proliferation, differentiation and survival. Both sexes were exposed to a wide variety of stressors, where after differences in HPA-axis reactivity and neurogenesis were assessed. To study the role of oestradiol in potential sex differences, ovariectomized females received low or high physiological oestradiol level replacement pellets. The results show that females in general have a higher basal and stress-induced HPA-axis activity than males, with minimal differences between the two female groups. Cell proliferation in the dorsal hippocampus was significantly higher in high oestradiol females compared to low oestradiol females and males, while doublecortin (DCX) expression as a marker of cell differentiation was significantly higher in males compared to females, independent of oestradiol level. Stress exposure did not significantly influence cell proliferation or survival of new cells, but did reduce DCX expression. In conclusion, despite the male-female differences in HPA-axis activity, the effect of repeated stress exposure on hippocampal cell differentiation was not significantly different between sexes. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of water stress and harvesting stages on quantitative and qualitative yields of coriander (Coriandrum sativum L.

Directory of Open Access Journals (Sweden)

A. Ahmadian

2016-05-01

Full Text Available In order to study the effect of drought stress and harvesting stages on quantitative and qualitative yields of Coriander (Coriandrum sativum L. this experiment was conducted on split plot based on a randomized completely block design with 3 replications in Torbat-e Heydariyeh University, Iran, during growing season of 2010-2011. Treatments were drought stress (in three levels no stress: control and irrigation in 60 and 30 percentage of FC as main plots and harvesting times (in 3 levels consist of: before flowering, flowering and after flowering as sub plots. Results showed that drought stress and harvesting stages had significant affected on leaf number, height, number of stem, wet and dry weight of plant, SPAD, proline content, carbohydrate content, essential oil yield and percentage and components of essential oil of coriander. Increasing water stress decreased yield and its components while enhanced proline and carbohydrate contents. Maximum of essential oil and its main components (linalool, alpha pentene, gamma terpinene, geranial acetate and camphor were in low stress that had significant difference with other stress treatments. Delaying in harvest enhanced yield and its components and essential oil percentage. Proline content had no significant difference between flowering and after flowering stages. Therefore, we can suggest low stress of water and harvest at after flowering stage to get maximum of yield.

Ab-initio atomic level stress and role of d-orbitals in CuZr, CuZn and CuY

Science.gov (United States)

Ojha, Madhusudan; Nicholson, Don M.; Egami, Takeshi

2015-03-01

Atomic level stress offers a new tool to characterize materials within the local approximation to density functional theory (DFT). Ab-initio atomic level stresses in B2 structures of CuZr, CuZn and CuY are calculated and results are explained on the basis of d-orbital contributions to Density of States (DOS). The overlap of d-orbital DOS plays an important role in the relative magnitude of atomic level stresses in these structures. The trends in atomic level stresses that we observed in these simple B2 structures are also seen in complex structures such as liquids, glasses and solid solutions. The stresses are however modified by the different coordination and relaxed separation distances in these complex structures. We used the Locally Self-Consistent Multiple Scattering (LSMS) code and Vienna Ab-initio Simulation Package (VASP) for ab-initio calculations.

Quality of life and level of post-traumatic stress disorder among trauma patients

DEFF Research Database (Denmark)

Danielsson, F B; Schultz Larsen, M; Nørgaard, B

2018-01-01

BACKGROUND: The aim of this study was to assess outcome in long-term quality of life (QoL) and post-traumatic stress disorder (PTSD) among adult survivors of trauma. Secondary aim was to compare levels of the outcome with injury severity and specialization level of two trauma centres. METHODS...... Scale. PTSD symptoms were classified according to the Post-Traumatic Stress Disorder Checklist (PCL) and Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). RESULTS: A questionnaire was mailed to 774 patients at end of 2014 or early 2015, 455 were included for analysis; median...

Immunoreactive cortisone in droppings reflect stress levels, diet and growth rate of gull-billed tern chicks.

Science.gov (United States)

Albano, Noelia; Santiago-Quesada, Francisco; Masero, José A; Sánchez-Guzmán, Juan M; Möstl, Erich

2015-03-01

Blood levels of corticosterone have been traditionally analyzed to assess stress levels in birds; however, measuring steroid hormone metabolites in feces and droppings has gained much interest as a noninvasive technique successfully used for such purposed in vertebrates. Diet may affect these fecal metabolite levels (e.g., due to nutritional stress), however, this variable has not been taken into account in studies with chicks despite the great dietary flexibility of many avian species. In this study, we addressed for the first time this key issue and validated the technique in wild gull-billed tern chicks (Gelochelidon nilotica). Several enzyme immunoassays were used to determine the most appropriate test to measure the stress response. Subsequently, we performed an experiment in captivity to assess adrenocortical activity in gull-billed tern chicks fed with two diets: piscivorous vs. insectivorous. Finally, the relation between the chicks' growth rate and excreted immunoreactive glucocorticoid metabolites (EGMs) was also evaluated. We found the immunoreactive cortisone metabolites to be a good index of stress (as being an index of adrenocortical reactivity) in chicks of this species. Fish-fed chicks had higher levels of cortisone metabolites when comparing both concentration and total daily excreted metabolites. Within each treatment diet, cortisone metabolite levels and growth rates were negatively correlated. These findings suggest that the diet should be considered when using this technique for comparative purposes and highlight the trade-off between stress levels and chicks growth rates. Copyright © 2015 Elsevier Inc. All rights reserved.

Response of antioxidant system to drought stress and re-watering in Alfalfa during branching

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Tina, R. R.; Shan, X. R.; Wang, Y.; Guo, S. Y.; Mao, B.; Wang, W.; Wu, H. Y.; Zhao, T. H.

2017-11-01

This paper aimed to reveal the response mechanism of active oxygen metabolism and antioxidant enzyme activities in Alfalfa under drought stress and re-watering, and the pot experiment was used, to explore the changes of H2O2, O2·-, electrolyte leakage conductivity and MDA, SOD, POD, CAT activity in Golden Empress (tolerant cultivar) and Sanditi (non-tolerant cultivar) under drought stress and re-watering during branching stage. Three water gradients were set up: CK (Maximum field capacity of 75%±5%), T1 (Maximum field capacity of 45%±5%), T2 (Maximum field capacity of 35%±5%) to compare, and the drought rehydration was also studied. Results: the results indicated that H2O2 content, O2·-production rate, relative conductivity and MDA content were higher than the control, and the increase extent of Golden Empress was higher than the Sanditi under drought stress and after re-watering the recovery capability of Golden Empress was also higher than the Sanditi. After 7 days of re-watering, all indexes were restored to the control level, indicating that the re-watering have compensation effect after drought. After drought stress, to weaken the damage of active oxygen Golden Empress was mainly by increasing the activity of POD and SOD, but Sanditi was mainly through the POD and CAT activity increased to effectively remove ROS. Under drought stress, active oxygen in leaves of Alfalfa increased, and thus the membrane system was damaged which lead to the increase of MDA content and relative electric conductivity. Plants play a defensive role by increasing the activity of antioxidant enzymes and scavenging reactive oxygen species. After re-watering, the stress effect was reduced, and the physiological indexes of plants were restored to the control level. In general, tolerant cultivar has stronger antioxidant properties under drought and re-watering.

Climate-related environmental stress in intertidal grazers: scaling-up biochemical responses to assemblage-level processes

Directory of Open Access Journals (Sweden)

Elena Maggi

2016-10-01

Full Text Available Background Organisms are facing increasing levels of environmental stress under climate change that may severely affect the functioning of biological systems at different levels of organization. Growing evidence suggests that reduction in body size is a universal response of organisms to global warming. However, a clear understanding of whether extreme climate events will impose selection directly on phenotypic plastic responses and how these responses affect ecological interactions has remained elusive. Methods We experimentally investigated the effects of extreme desiccation events on antioxidant defense mechanisms of a rocky intertidal gastropod (Patella ulyssiponensis, and evaluated how these effects scaled-up at the population and assemblage levels. Results With increasing levels of desiccation stress, limpets showed significant lower levels of total glutathione, tended to grow less and had reduced per capita interaction strength on their resources. Discussion Results suggested that phenotypic plasticity (i.e., reduction in adults’ body size allowed buffering biochemical responses to stress to scale-up at the assemblage level. Unveiling the linkages among different levels of biological organization is key to develop indicators that can anticipate large-scale ecological impacts of climate change.

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.

Conceptual framework and trend analysis of water-level responses to hydrologic stresses, Pahute Mesa–Oasis Valley groundwater basin, Nevada, 1966-2016

Science.gov (United States)

Jackson, Tracie R.; Fenelon, Joseph M.

2018-05-31

This report identifies water-level trends in wells and provides a conceptual framework that explains the hydrologic stresses and factors causing the trends in the Pahute Mesa–Oasis Valley (PMOV) groundwater basin, southern Nevada. Water levels in 79 wells were analyzed for trends between 1966 and 2016. The magnitude and duration of water-level responses to hydrologic stresses were analyzed graphically, statistically, and with water-level models.The conceptual framework consists of multiple stress-specific conceptual models to explain water-level responses to the following hydrologic stresses: recharge, evapotranspiration, pumping, nuclear testing, and wellbore equilibration. Dominant hydrologic stresses affecting water-level trends in each well were used to categorize trends as nonstatic, transient, or steady state.The conceptual framework of water-level responses to hydrologic stresses and trend analyses provide a comprehensive understanding of the PMOV basin and vicinity. The trend analysis links water-level fluctuations in wells to hydrologic stresses and potential factors causing the trends. Transient and steady-state trend categorizations can be used to determine the appropriate water-level data for groundwater studies.

Optimization of Bolt Stress

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard

2013-01-01

The state of stress in bolts and nuts with ISO metric thread design is examined and optimized. The assumed failure mode is fatigue so the applied preload and the load amplitude together with the stress concentrations define the connection strength. Maximum stress in the bolt is found at, the fillet...... under the head, at the thread start or at the thread root. To minimize the stress concentration shape optimization is applied....

Changes in eosinophil and corticosterone levels and catecholamine metabolism during emotionalpainful stress

International Nuclear Information System (INIS)

Malyshev, V.V.; Manukhin, B.N.; Petrova, V.A.

1985-01-01

The aim of this investigation was to study blood levels of eosinophils, corticosterone (CS), adrenalin, noradrenalin (NA), and dopamine (DA) during the development of the stress reaction, and also to study neuronal uptake and synthesis of catecholamines in the adrenals and heart. In some animal groups, the neuronal uptake of 3 H-NA and the intensity of 3 H-Na and 3 H-DA synthesis from 3 H-tyrosine were investigated by a method described previously, 2 h after the end of induction of emotional-painful stress (EPS). Radioactivity was measured on an SL-30 liquid scintillation counter. A regular relationship was found between changes in blood eosinophil level, the CH concentration, and catecholamine metabolism in the course of EPS

Relative sea-level changes and crustal movements in Britain and Ireland since the Last Glacial Maximum

Science.gov (United States)

Shennan, Ian; Bradley, Sarah L.; Edwards, Robin

2018-05-01

The new sea-level database for Britain and Ireland contains >2100 data points from 86 regions and records relative sea-level (RSL) changes over the last 20 ka and across elevations ranging from ∼+40 to -55 m. It reveals radically different patterns of RSL as we move from regions near the centre of the Celtic ice sheet at the last glacial maximum to regions near and beyond the ice limits. Validated sea-level index points and limiting data show good agreement with the broad patterns of RSL change predicted by current glacial isostatic adjustment (GIA) models. The index points show no consistent pattern of synchronous coastal advance and retreat across different regions, ∼100-500 km scale, indicating that within-estuary processes, rather than decimetre- and centennial-scale oscillations in sea level, produce major controls on the temporal pattern of horizontal shifts in coastal sedimentary environments. Comparisons between the database and GIA model predictions for multiple regions provide potentially powerful constraints on various characteristics of global GIA models, including the magnitude of MWP1A, the final deglaciation of the Laurentide ice sheet and the continued melting of Antarctica after 7 ka BP.

The last glacial maximum

Science.gov (United States)

Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

2009-01-01

We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

NMR-Based Metabonomic Investigation of Heat Stress in Myotubes Reveals a Time-Dependent Change in the Metabolites

DEFF Research Database (Denmark)

Straadt, Ida K; Young, Jette F; Bross, Peter

2010-01-01

NMR-based metabonomics was applied to elucidate the time-dependent stress responses in mouse myotubes after heat exposure of either 42 or 45 degrees C for 1 h. Principal component analysis (PCA) revealed that the gradual time-dependent changes in metabolites contributing to the clustering...... and separation of the control samples from the different time points after heat stress primarily are in the metabolites glucose, leucine, lysine, phenylalanine, creatine, glutamine, and acetate. In addition, PC scores revealed a maximum change in metabolite composition 4 h after the stress exposure; thereafter......, samples returned toward control samples, however, without reaching the control samples even 10 h after stress. The results also indicate that the myotubes efficiently regulate the pH level by release of lactate to the culture medium at a heat stress level of 42 degrees C, which is a temperature level...

Obesity and chronic stress are able to desynchronize the temporal pattern of serum levels of leptin and triglycerides.

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de Oliveira, Carla; Scarabelot, Vanessa Leal; de Souza, Andressa; de Oliveira, Cleverson Moraes; Medeiros, Liciane Fernandes; de Macedo, Isabel Cristina; Marques Filho, Paulo Ricardo; Cioato, Stefania Giotti; Caumo, Wolnei; Torres, Iraci L S

2014-01-01

Disruption of the circadian system can lead to metabolic dysfunction as a response to environmental alterations. This study assessed the effects of the association between obesity and chronic stress on the temporal pattern of serum levels of adipogenic markers and corticosterone in rats. We evaluated weekly weight, delta weight, Lee index, and weight fractions of adipose tissue (mesenteric, MAT; subcutaneous, SAT; and pericardial, PAT) to control for hypercaloric diet-induced obesity model efficacy. Wistar rats were divided into four groups: standard chow (C), hypercaloric diet (HD), stress plus standard chow (S), and stress plus hypercaloric diet (SHD), and analyzed at three time points: ZT0, ZT12, and ZT18. Stressed animals were subjected to chronic stress for 1h per day, 5 days per week, during 80 days. The chronic exposure to a hypercaloric diet was an effective model for the induction of obesity and metabolic syndrome, increasing delta weight, Lee index, weight fractions of adipose tissue, and triglycerides and leptin levels. We confirmed the presence of a temporal pattern in the release of triglycerides, corticosterone, leptin, and adiponectin in naïve animals. Chronic stress reduced delta weight, MAT weight, and levels of triglycerides, total cholesterol, and leptin. There were interactions between chronic stress and obesity and serum total cholesterol levels, between time points and obesity and adiponectin and corticosterone levels, and between time points and chronic stress and serum leptin levels. In conclusion, both parameters were able to desynchronize the temporal pattern of leptin and triglyceride release, which could contribute to the development of metabolic diseases such as obesity and metabolic syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

Chronic family stress moderates the association between a TOMM40 variant and triglyceride levels in two independent Caucasian samples.

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Jiang, Rong; Brummett, Beverly H; Hauser, Elizabeth R; Babyak, Michael A; Siegler, Ilene C; Singh, Abanish; Astrup, Arne; Pedersen, Oluf; Hansen, Torben; Holst, Claus; Sørensen, Thorkild I A; Williams, Redford B

2013-04-01

TOMM40 SNP rs157580 has been associated with triglyceride levels in genome-wide association studies (GWAS). Chronic caregiving stress moderates the association between triglyceride levels and a nearby SNP rs439401 that is associated with triglyceride levels in GWAS. Here, we report data from two independent Caucasian samples (242 U.S. women and men; 466 Danish men) testing the hypothesis that chronic family stress also moderates the association between rs157580 and triglyceride levels. The interaction of rs157580 and family stress in predicting triglyceride levels was statistically significant in the U.S. sample (p=0.004) and marginally significant (p=0.075) in the Danish sample. The G allele of rs157580 was associated with increased triglyceride levels among family stressed cases in both samples compared with A/A cases, but not among controls. Chronic family stress moderates the association of rs157580 variants with triglyceride levels and should be taken into account for disease risk assessment and potential intervention. Copyright © 2013 Elsevier B.V. All rights reserved.

Fatigue Behavior of Steel Fiber Reinforced High-Strength Concrete under Different Stress Levels

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Zhang, Chong; Gao, Danying; Gu, Zhiqiang

2017-12-01

The investigation was conducted to study the fatigue behavior of steel fiber reinforced high-strength concrete (SFRHSC) beams. A series of 5 SFRHSC beams was conducted flexural fatigue tests at different stress level S of 0.5, 0.55, 0.6, 0.7 and 0.8 respectively. Static test was conducted to determine the ultimate static capacity prior to fatigue tests. Fatigue modes and S-N curves were analyzed. Besides, two fatige life prediction model were analyzed and compared. It was found that stress level S significantly influenced the fatigue life of SFRHSC beams and the fatigue behavior of SFRHSC beams was mainly determined by the tensile reinforcement.

Mental health of Japanese psychiatrists: the relationship among level of occupational stress, satisfaction and depressive symptoms.

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Koreki, Akihiro; Nakagawa, Atsuo; Abe, Akiko; Ikeuchi, Hidetsugu; Okubo, Jo; Oguri, Atsushi; Orimo, Keisuke; Katayama, Nariko; Sato, Hiroyo; Shikimoto, Ryo; Nishiyama, Go; Nogami, Waka; Haki, Kazuma; Hayashi, Tetsuro; Fukagawa, Yuko; Funaki, Kei; Matsuzawa, Mia; Matsumoto, Ayako; Mimura, Masaru

2015-03-26

Psychiatrists in clinical practice face a number of stressors related to patient care, such as overwork. On the other hand, they gain satisfaction from their work. We quantified and assessed the potential relationship between levels of occupational stress, satisfaction, and depressive symptoms among Japanese clinical psychiatrists. We surveyed 206 psychiatrists with up to 15 years of clinical experience who primarily worked in patient care. Levels of occupational stress and occupational satisfaction were measured using the Visual Analogue Scale and the level of depressive symptoms was measured by the Center for Epidemiologic Studies Depression Scale. Workplace stressors and satisfiers were also evaluated. Out of 206 psychiatrists, 154 (74.8%) responded to the survey. The respondents' mean (SD) age was 34.3 (5.2) years. The estimated prevalence of significant depressive symptoms was 34.4% (n = 53), and the experienced frequent violence was 14.9% (n = 23). The level of depressive symptoms was inversely correlated with the level of occupational satisfaction. In respondents who reported a moderate level of occupational stress, having fewer depressive symptoms was associated with higher occupational satisfaction, but this association was not significant in those who reported a high level of stress. In addition, high occupational satisfaction was associated with interest towards work content, ability to work at one's discretion, opportunities for growth and career development, and ease of communication with supervisors and colleagues. Nearly one-third of the psychiatrists screened positive for significant depressive symptoms. Having fewer depressive symptoms was associated with higher occupational satisfaction in those who reported a moderate level of stress. Implications from the present findings may be to enhance occupational satisfaction by discussing work interests with a supervisor, as well as increased opportunities for career development, which may

Work stress, occupational burnout and depression levels: a clinical study of paediatric intensive care unit nurses in Taiwan.

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Lin, Tzu-Ching; Lin, Huey-Shyan; Cheng, Su-Fen; Wu, Li-Min; Ou-Yang, Mei-Chen

2016-04-01

This study aimed to examine the relationship between work stress and depression; and investigate the mediating effect of occupational burnout among nurses in paediatric intensive care units. The relationships among work stress, occupational burnout and depression level have been explored, neither regarding occupational burnout as the mediating role that causes work stress to induce depression nor considering the paediatric intensive care unit context. A cross-sectional correlational design was conducted. One hundred and forty-four female paediatric intensive care unit nurses from seven teaching hospitals in southern Taiwan were recruited as the participants. Data were collected by structured questionnaires including individual demographics, the Nurse Stress Checklist, the Occupational Burnout Inventory and the Taiwan Depression Questionnaire. The results indicated that after controlling for individual demographic variables, the correlations of work stress with occupational burnout, as well as work stress and occupational burnout with depression level were all positive. Furthermore, occupational burnout may exert a partial mediating effect on the relationship between work stress and depression level. This study provides information about work stress, occupational burnout and depression level, and their correlations, as well as the mediating role of occupational burnout among paediatric intensive care unit nurses. It suggests government departments and hospital administrators when formulating interventions to prevent work stress and occupational burnout. These interventions can subsequently prevent episodes of depression in paediatric intensive care unit nurses, thereby providing patients with a safe and high-quality nursing environment. © 2016 John Wiley & Sons Ltd.

Plasma oxidative stress level of IgA nephropathy in children and the effect of early intervention with angiotensin-converting enzyme inhibitors.

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Pei, Yuxin; Xu, Yuanyuan; Ruan, Jingwei; Rong, Liping; Jiang, Mengjie; Mo, Ying; Jiang, Xiaoyun

2016-01-01

The purpose of this study was to investigate the change of the plasma oxidative stress level in children with IgA nephropathy (IgAN) and analyze its relativity to the clinical and pathological classification. To discuss the early effects of angiotensin-converting enzyme inhibitors (ACEIs) on the plasma oxidative stress level in children with IgA nephropathy. Thirty-eight children with IgAN were divided into groups according to their clinical features, pathologic grades, and treatments. Twenty healthy children were included in the control group. The plasma level of advanced oxidation protein products (AOPPs), malonaldehyde (MDA), and superoxide dismutase (SOD) were detected. The plasma level of oxidative stress was significantly increased in the IgAN group, including a higher plasma level of AOPP and MDA and a lower plasma level of SOD. After treatment, the plasma level of oxidative stress was significantly decreased in the ACEI group. The children with IgAN had an increase in the plasma level of oxidative stress, expressed as an increased plasma level of AOPP and MDA and a decreased plasma level of SOD. Oxidative stress was associated with the progression of IgAN in children. Early treatment with ACEI therapy can significantly reduce the plasma level of oxidative stress in children with IgAN. © The Author(s) 2016.

Predicted strains in austenitic stainless steels at stresses above yield

International Nuclear Information System (INIS)

Hammond, J.P.; Sikka, V.K.

1977-01-01

Tensile results on austenitic stainless steels were analyzed to develop means for predicting strains at stresses above yield for reactor regulatory applications. Eight heats each of types 316 and 304 were tested at 24, 93, 204, and 316 0 C as mill-annealed and at 24 0 C after reannealing. The effects of heat-to-heat variations on total strain (to 5%) at discrete stress levels were portrayed by a rational polynomial incorporating three constants that relate to the basic features of the true-stress-true-strain diagram. Because these constants usually are interrelated, a single parameter, yield strength (YS), proved adequate to predict results. For predictions analytical expressions of yield strength, an average value (YSa), and a lower bound value [YSa - 1.65SEE (standard error of estimate)] were used. Using the rational polynomial with these parameters we determined (1) limits of total maximum strain and (2) ratios of strain of material of lower bound YS to that of average YS. These are recorded at regular increments of stress [34 MPa (5 ksi)] and at ASME Code-related stresses (S/sub y), S/sub m/, 1.2S/sub m/ and 1.5S/sub m/). At intermediate stresses, strain penalties for using material of lower bound strength were large, generally larger for type 316 than type 304. For mill-annealed type 316 at 24, 93, 204, and 316 0 C, the maximum ratios of strain were 8.8, 13.0, 14.1, and 14.9, respectively, whereas for type 304 they were 3.5, 3.4, 5.6, and 4.6. At 1.5S/sub m/ and 316 0 C, a maximum strain of 2.08% was predicted for type 316 and 1.66% for type 304, as contrasted to values of 0.14 and 0.39% for average strain

Assessment the effect of NO inhibition on hippocampal normetanephrine level in stress and non-stress conditions in adult male rats

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Hana Molahoveizeh

2016-01-01

Full Text Available Background: Nitric oxide (NO has a role in the regulation of neurotransmitters release such as norepinephrine, in the hippocampus.Normetanephrine (NMN is a metabolite of norepinephrine created by action of catechol-O-methyl transferase (COMT on norepinephrine. Several studies have shown that various stresses increased release of norepinephrine and its metabolites. Therefore in the present study, the role of Nitric oxide in regulation of norepinephrine release and its metabolism was investigated by administration of L-NAME (NO synthase inhibitor in stressed and non-stressed rats. Materials and Methods: For this purpose, 50 adult rats were divided into 10 groups, of which 5 groups were exposed to restraint stress while another 5 groups were without stress. These two set of groups included intact, saline and L-NAME (20, 40, 80 mg/kg. Thirty minutes after intraperituneal injection of L-NAME, brains removed, the hippocampus dissected, weighed, homogenized and centrifuged then amount of NMN measured by ELISA kit. Results: The results showed that in non-stressed condition amount of NMN were significantly increased in group that received L-NAME (80 mg/kg in comparison with other groups but in stress condition, amount of NMN was significantly decreased in groups that received L-NAME (20,40,80 mg/kg, in comparison with control and saline groups. Comparison between stress and non-stressed groups showed that stress alone cause an increase in amount of NMN in control and saline groups. Conclusion: In conclusion, NO synthesis inhibition produced opposite responses with respect to NMN amount in the presence or absence of stress, and probably L-NAME preventing the effect of stress on increasing NMN levels mediated by nitrergic pathway.

Relationship between job stress level and coping strategies used by Hong Kong nurses working in an acute surgical unit.

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Wang, Wenru; Kong, Amelia Wai Man; Chair, Sek Ying

2011-11-01

The aim of this study is to explore the relationship between job stress and coping strategies of Hong Kong nurses working in an acute surgical unit. This is a descriptive correlational study. Data were collected from 98 Hong Kong surgical nurses using the Nursing Stress Scale and the Jalowiec Coping Scale. Results showed that workload (M = 15.36), lack of support (M = 13.32), and inadequate preparation (M = 12.33) are the most common stressors for Hong Kong surgical nurses. The most frequent strategies used by nurses to cope with stress can be characterized as evasive (M = 19.23), confrontive (M = 17.46), and optimistic (M = 15.81), all of which are also rated as the most effective strategies in reducing stress levels. Only the confrontive, optimistic, supportant, and emotive coping strategies reveal significant correlations (p stress levels of nurses, whereas the evasive, fatalistic, palliative, and self-reliant strategies showed no significant correlation with stress levels (p > .05). Recognizing the impacts of job-related stress and making use of effective coping methods play a vital role in reducing nurse's stress. A change in leadership styles from the managerial level and reallocation of manpower may help reduce job stress. The use of confrontive and optimistic coping strategies in reducing job-related stress for surgical nurses should be advocated and promoted in their daily work. Copyright © 2011 Elsevier Inc. All rights reserved.

In situ stress measurements at 250m gallery off the ventilation shaft

International Nuclear Information System (INIS)

Nakamura, Takahiro; Sanada, Hiroyuki; Sugita, Yutaka; Kato, Harumi

2011-06-01

boreholes. Shut-in pressure of inclined transverse cracks and the circumferential position of longitudinal cracks on the wellbore surface were used to determine the magnitude and orientation of principal stress around the 250m gallery on the assumption that all of the target zones of hydraulic fracturing were in a uniform stress state. The determined in situ stress state showed a little difference of magnitude between intermediate stress and minimum stress. The vertical component of the in situ stress was evaluated to be about a half of the overburden at the test site. The maximum principal stress was inclined to about 40 degrees from the level with azimuth of NE orientation. The reason why the evaluated state of stress at 140m niches and 250m gallery are different would be attributed to geological environment. (2) Stress relief method by conical-ended borehole overcoring. Stress relief method by conical-ended borehole overcoring was successfully conducted at the depths of 17.25m and 17.72m of the borehole 09-V250-M02. Orientation of the evaluated principal stresses at the two depths showed a good agreement. The maximum principal stress inclined about 60 degrees from the level with azimuth of NNE and the intermediate principal stress was almost horizontal with WNW orientation. The orientation of the maximum principal stress was almost perpendicular to the plane of sedimentation of Koetoi formation and Wakkanai formation. The magnitude of the maximum principal stress was comparable to the uniaxial compressive strength of Wakkanai formation. The estimated ratio of the principal stresses σ 1 /σ 3 was 11.6 and 6.0 at the depth of 17.25m and 17.72m, respectively. No spalling of the walls of the boreholes due to the stress concentration was detected while both the magnitude and the ratio of principal stress were large enough to cause borehole breakout. The inconsistency would be explained by microcracks in the boring core formed during the drilling process or/and by elastic

Impact of drought stress on specialised metabolism: Biosynthesis and the expression of monoterpene synthases in sage (Salvia officinalis).

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Radwan, Alzahraa; Kleinwächter, Maik; Selmar, Dirk

2017-09-01

In previous experiments, we demonstrated that the amount of monoterpenes in sage is increased massively by drought stress. Our current study is aimed to elucidate whether this increase is due, at least in part, to elevated activity of the monoterpene synthases responsible for the biosynthesis of essential oils in sage. Accordingly, the transcription rates of the monoterpene synthases were analyzed. Salvia officinalis plants were cultivated under moderate drought stress. The concentrations of monoterpenes as well as the expression of the monoterpene synthases were analyzed. The amount of monoterpenes massively increased in response to drought stress; it doubled after just two days of drought stress. The observed changes in monoterpene content mostly match with the patterns of monoterpene synthase expressions. The expression of bornyl diphosphate synthase was strongly up-regulated; its maximum level was reached after two days. Sabinene synthase increased gradually and reached a maximum after two weeks. In contrast, the transcript level of cineole synthase continuously declined. This study revealed that the stress related increase of biosynthesis is not only due to a "passive" shift caused by the stress related over-reduced status, but also is due - at least in part-to an "active" up-regulation of the enzymes involved. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stress on stress response of wild mussels, Mytilus edulis and Mytilus trossulus, as an indicator of ecosystem health

International Nuclear Information System (INIS)

Hellou, J.; Law, R.J.

2003-01-01

Mussels' health as indicated by the survival time of 50% of sampled animals (LT 50 ) when maintained in air at 15 deg. C was examined at three sites in Halifax Harbour with expected differing levels of contamination. Condition and gonad indices, lipid content and the body burden of polycyclic aromatic compounds (PACs) were compared with this stress response in 60 groups of mussels covering two species. At each sampling time, the bioaccumulation of PACs, lipid content and condition indices were higher whithin Mytilus edulis and Mytilus trossulus displaying shorter survival than at the other sites. M. edulis was generally more tolerant than M. trossulus (for n=11, LT 50 of 9.3 and 7.9 days), with indications of shorter and later gonad development in M. trossulus. Minimum and maximum tolerance was apparent in June and October (LT 50 spanning 3-14 days), respectively. Our results indicate that the stress on stress response provides a simple and sensitive indicator of environmental health, which could be integrated with mussel watch studies. - Stress on stress response is a simple and sensitive indicator of environmental condition

Professional stress in general practitioners and psychiatrists: The level of psycologic distress and burnout risk

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Vićentić Sreten

2010-01-01

Full Text Available Background/Aim. So far, studies of stress have shown that physicians are at a high risk of sickness from psychic and somatic disorders related to professional stress, that can lead to important disturbance of personal, familiar and professional functionating. The aim of this study was to investigate the doctors exposition level to professional stress, to compare stress level in general practitioners (GP group with that in the group of psychiatrists and risk level for the apperance of burnout syndrome. Methods. This cross-section study included subjects recruited by a random sample method. Thirty General Practice doctors and 30 psychiatrists (totally 60 doctors filled the set of 3 questionnaires: Sociodemographics features, General Health Questionnaire (GHQ; Goldberg D, 1991, and Maslach Burnout Inventory (MBI; Maslach C, 1996. Appropriate statistical procedures (Pearson test, t-test, variance analysis in interpretation of the results were used. Results. A total level of psychic distress measured with the GHQ test in both groups of physicians was very low implying their good mental health. A difference in Burnout risk based on MBI test between the groups was statistically significant (χ2 = 4,286; p < 0.05 only at subscale Personal Accomplishment (MBI-PA; it was a consequence of a higher number of GPs with medium burnout risk (13.3 : 0.0%. However, even 35 physicians from the sample were affected with a high burnout risk measured with subscales Emotional Ehausation (MBI-EE and MBI-DP, showing that both groups of physicians had risk for the appearance of burnout syndrome. Conclusion. The obtained results showed a high burnout risk level in both, GPs and psychiatrists, groups. In both groups there was no presence of psychic disorders (anxiety, depression, insomnia, while there was a high level of emotional ehausation and overtension by job, and also a lower total personal accomplishment. Level of exposition to professional stress is higher in GPs

Stress-induced heating in commercial conductors and its possible influence on magnet performance

International Nuclear Information System (INIS)

Easton, D.S.; Kroeger, D.M.; Moazed, A.

1976-01-01

Calorimetric measurements show that significant amounts of heat are generated when a multifilamentary composite conductor is stressed in tension to levels expected to occur in large, high-field magnet systems. When the stress on the conductor is repetitively cycled between zero and some maximum value, the amount of heat produced per cycle is constant after the first few cycles. Comparison is made between calorimetric determinations of heat injections and the work done on the specimen as indicated by stress-strain curves. Stress-strain curves for a number of commercial conductors indicate that the most important determinant of the magnitude of this effect is the choice of matrix material

The association between high levels of cumulative life stress and aberrant resting state EEG dynamics in old age.

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Marshall, Amanda C; Cooper, Nicholas R

2017-07-01

Cumulative experienced stress produces shortcomings in old adults' cognitive performance. These are reflected in electrophysiological changes tied to task execution. This study explored whether stress-related aberrations in older adults' electroencephalographic (EEG) activity were also apparent in the system at rest. To this effect, the amount of stressful life events experienced by 60 young and 60 elderly participants were assessed in conjunction with resting state power changes in the delta, theta, alpha, and beta frequencies during a resting EEG recording. Findings revealed elevated levels of delta power among elderly individuals reporting high levels of cumulative life stress. These differed significantly from young high and low stress individuals and old adults with low levels of stress. Increases of delta activity have been linked to the emergence of conditions such as Alzheimer's Disease and Mild Cognitive Impairment. Thus, a potential interpretation of our findings associates large amounts of cumulative stress with an increased risk of developing age-related cognitive pathologies in later life. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of processing conditions on residual stress distributions by bead-on-plate welding after surface machining

International Nuclear Information System (INIS)

Ihara, Ryohei; Mochizuki, Masahito

2014-01-01

Residual stress is important factor for stress corrosion cracking (SCC) that has been observed near the welded zone in nuclear power plants. Especially, surface residual stress is significant for SCC initiation. In the joining processes of pipes, butt welding is conducted after surface machining. Residual stress is generated by both processes, and residual stress distribution due to surface machining is varied by the subsequent butt welding. In previous paper, authors reported that residual stress distribution generated by bead on plate welding after surface machining has a local maximum residual stress near the weld metal. The local maximum residual stress shows approximately 900 MPa that exceeds the stress threshold for SCC initiation. Therefore, for the safety improvement of nuclear power plants, a study on the local maximum residual stress is important. In this study, the effect of surface machining and welding conditions on residual stress distribution generated by welding after surface machining was investigated. Surface machining using lathe machine and bead on plate welding with tungsten inert gas (TIG) arc under various conditions were conducted for plate specimens made of SUS316L. Then, residual stress distributions were measured by X-ray diffraction method (XRD). As a result, residual stress distributions have the local maximum residual stress near the weld metal in all specimens. The values of the local maximum residual stresses are almost the same. The location of the local maximum residual stress is varied by welding condition. It could be consider that the local maximum residual stress is generated by same generation mechanism as welding residual stress in surface machined layer that has high yield stress. (author)

Designing automation for complex work environments under different levels of stress.

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Sauer, Juergen; Nickel, Peter; Wastell, David

2013-01-01

This article examines the effectiveness of different forms of static and adaptable automation under low- and high-stress conditions. Forty participants were randomly assigned to one of four experimental conditions, comparing three levels of static automation (low, medium and high) and one level of adaptable automation, with the environmental stressor (noise) being varied as a within-subjects variable. Participants were trained for 4 h on a simulation of a process control environment, called AutoCAMS, followed by a 2.5-h testing session. Measures of performance, psychophysiology and subjective reactions were taken. The results showed that operators preferred higher levels of automation under noise than under quiet conditions. A number of parameters indicated negative effects of noise exposure, such as performance impairments, physiological stress reactions and higher mental workload. It also emerged that adaptable automation provided advantages over low and intermediate static automation, with regard to mental workload, effort expenditure and diagnostic performance. The article concludes that for the design of automation a wider range of operational scenarios reflecting adverse as well as ideal working conditions needs to be considered. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Thermo-mechanical stress analysis of cryopreservation in cryobags and the potential benefit of nanowarming.

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Solanki, Prem K; Bischof, John C; Rabin, Yoed

2017-06-01

Cryopreservation by vitrification is the only promising solution for long-term organ preservation which can save tens of thousands of lives across the world every year. One of the challenges in cryopreservation of large-size tissues and organs is to prevent fracture formation due to the tendency of the material to contract with temperature. The current study focuses on a pillow-like shape of a cryobag, while exploring various strategies to reduce thermo-mechanical stress during the rewarming phase of the cryopreservation protocol, where maximum stresses are typically found. It is demonstrated in this study that while the level of stress may generally increase with the increasing amount of CPA filled in the cryobag, the ratio between width and length of the cryobag play a significant role. Counterintuitively, the overall maximum stress is not found when the bag is filled to its maximum capacity (when the filled cryobag resembles a sphere). Parametric investigation suggests that reducing the initial rewarming rate between the storage temperature and the glass transition temperature may dramatically decrease the thermo-mechanical stress. Adding a temperature hold during rewarming at the glass transition temperature may reduce the thermo-mechanical stress in some cases, but may have an adverse effect in other cases. Finally, it is demonstrated that careful incorporation of volumetric heating by means on nanoparticles in an alternating magnetic field, or nanowarming, can dramatically reduce the resulting thermo-mechanical stress. These observations display the potential benefit of a thermo-mechanical design of the cryopreservation protocols in order to prevent structural damage. Copyright © 2017 Elsevier Inc. All rights reserved.

A Two-Stage Information-Theoretic Approach to Modeling Landscape-Level Attributes and Maximum Recruitment of Chinook Salmon in the Columbia River Basin.

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Thompson, William L.; Lee, Danny C.

2000-11-01

Many anadromous salmonid stocks in the Pacific Northwest are at their lowest recorded levels, which has raised questions regarding their long-term persistence under current conditions. There are a number of factors, such as freshwater spawning and rearing habitat, that could potentially influence their numbers. Therefore, we used the latest advances in information-theoretic methods in a two-stage modeling process to investigate relationships between landscape-level habitat attributes and maximum recruitment of 25 index stocks of chinook salmon (Oncorhynchus tshawytscha) in the Columbia River basin. Our first-stage model selection results indicated that the Ricker-type, stock recruitment model with a constant Ricker a (i.e., recruits-per-spawner at low numbers of fish) across stocks was the only plausible one given these data, which contrasted with previous unpublished findings. Our second-stage results revealed that maximum recruitment of chinook salmon had a strongly negative relationship with percentage of surrounding subwatersheds categorized as predominantly containing U.S. Forest Service and private moderate-high impact managed forest. That is, our model predicted that average maximum recruitment of chinook salmon would decrease by at least 247 fish for every increase of 33% in surrounding subwatersheds categorized as predominantly containing U.S. Forest Service and privately managed forest. Conversely, mean annual air temperature had a positive relationship with salmon maximum recruitment, with an average increase of at least 179 fish for every increase in 2 C mean annual air temperature.

Sensitivity of anterior pituitary hormones to graded levels of psychological stress.

Science.gov (United States)

Armario, A; Lopez-Calderón, A; Jolin, T; Castellanos, J M

1986-08-04

The effect of graded levels of stressor intensity on anterior pituitary hormones was studied in adult male rats. Corticosterone, considered as a reflection of ACTH release, and prolactin responses showed a good correlation with the intensity of the stressors. On the contrary, neither LH, GH nor TSH release showed a parallelism with the intensity of the stressors in spite of the fact that they clearly responded to all the stimuli. It appears that the hormones of the anterior pituitary might be divided into two groups: those whose response is sensitive to the levels of emotional arousal elicited by stress, and those displaying a clear but stereotyped response during stress. However, other alternative explanations might exist to justify the present results. The neural mechanisms underlying the two types of response are at present unknown. These data indicate that only the pituitary-adrenal axis and prolactin have some potential utilities as quantitative indices of emotional arousal elicited by currently applied stressors in the rat.

Elite sport is not an additional source of distress for adolescents with high stress levels.

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Gerber, Markus; Holsboer-Trachsler, Edith; Pühse, Uwe; Brand, Serge

2011-04-01

This study examined whether participation in elite sport interacts with stress in decreasing or increasing symptoms of depression and anxiety among adolescents, and further, whether the interplay between participation in high-performance sport and stress is related to the perceived quality of sleep. 434 adolescents (278 girls, 156 boys; age: M = 17.2 yr.) from 15 "Swiss Olympic Sport Classes" and 9 conventional classes answered a questionnaire and completed a 7-day sleep log. Analyses of covariance showed that heightened stress was related to more depressive symptoms and higher scores for trait-anxiety. Moreover, those classified as having poor sleep by a median split cutoff reported higher levels of depressive symptoms. No significant (multivariate) main effects were found for high-performance sport athletes. Similarly, no significant two- or three-way interaction effects were found. These results caution against exaggerated expectations concerning sport participation as a stress buffer. Nevertheless, participation in high-performance sport was not found to be an additional source of distress for adolescents who reported high stress levels despite prior research that has pointed toward such a relationship.

Factors associated with high stress levels in adults with diabetes mellitus attending a tertiary diabetes care center, Chennai, Tamil Nadu, India

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Muthappan Sendhilkumar

2017-01-01

Full Text Available Objective: We aimed to determine perceived stress levels among adults aged >20 years with type 2 diabetes mellitus (DM in a tertiary care diabetes center, Chennai, Tamil Nadu, India, assess their association with sociodemographic and clinical characteristics and assess the possible risk factors for stress and coping strategies. Methods: A mixed-methods (triangulation design study with quantitative methodology (survey and qualitative methodology (interviews was carried out. Stress levels were assessed among type 2 DM patients attending a diabetes clinic using a 5-point perceived stress scale-10. One-on-one interviews were carried out with 376 participants with DM having high/very high stress levels to understand the reasons for perceived stress and explore their coping mechanisms. Results: The prevalence of high/very high stress was 35% among DM patients. Age 30–40 years, working in professional jobs, and lack of physical activity were factors significantly associated with stress. The perceived major stress inducers were related to family, work, financial issues, and the disease itself. Conclusions: This study showed high levels of stress in more than one-third of DM patients. Potential solutions include regular, formal assessment of stress levels in the clinic, providing integrated counseling and psychological care for DM patients, and promoting physical activity.

Factors associated with high stress levels in adults with diabetes mellitus attending a tertiary diabetes care center, Chennai, Tamil Nadu, India.

Science.gov (United States)

Sendhilkumar, Muthappan; Tripathy, Jaya Prasad; Harries, Anthony D; Dongre, Amol R; Deepa, Mohan; Vidyulatha, Ashok; Poongothai, Subramanian; Venkatesan, Ulaganathan; Anjana, Ranjit Mohan; Mohan, Viswanathan

2017-01-01

We aimed to determine perceived stress levels among adults aged >20 years with type 2 diabetes mellitus (DM) in a tertiary care diabetes center, Chennai, Tamil Nadu, India, assess their association with sociodemographic and clinical characteristics and assess the possible risk factors for stress and coping strategies. A mixed-methods (triangulation design) study with quantitative methodology (survey) and qualitative methodology (interviews) was carried out. Stress levels were assessed among type 2 DM patients attending a diabetes clinic using a 5-point perceived stress scale-10. One-on-one interviews were carried out with 376 participants with DM having high/very high stress levels to understand the reasons for perceived stress and explore their coping mechanisms. The prevalence of high/very high stress was 35% among DM patients. Age 30-40 years, working in professional jobs, and lack of physical activity were factors significantly associated with stress. The perceived major stress inducers were related to family, work, financial issues, and the disease itself. This study showed high levels of stress in more than one-third of DM patients. Potential solutions include regular, formal assessment of stress levels in the clinic, providing integrated counseling and psychological care for DM patients, and promoting physical activity.

Factors associated with high stress levels in adults with diabetes mellitus attending a tertiary diabetes care center, Chennai, Tamil Nadu, India

Science.gov (United States)

Sendhilkumar, Muthappan; Tripathy, Jaya Prasad; Harries, Anthony D.; Dongre, Amol R.; Deepa, Mohan; Vidyulatha, Ashok; Poongothai, Subramanian; Venkatesan, Ulaganathan; Anjana, Ranjit Mohan; Mohan, Viswanathan

2017-01-01

Objective: We aimed to determine perceived stress levels among adults aged >20 years with type 2 diabetes mellitus (DM) in a tertiary care diabetes center, Chennai, Tamil Nadu, India, assess their association with sociodemographic and clinical characteristics and assess the possible risk factors for stress and coping strategies. Methods: A mixed-methods (triangulation design) study with quantitative methodology (survey) and qualitative methodology (interviews) was carried out. Stress levels were assessed among type 2 DM patients attending a diabetes clinic using a 5-point perceived stress scale-10. One-on-one interviews were carried out with 376 participants with DM having high/very high stress levels to understand the reasons for perceived stress and explore their coping mechanisms. Results: The prevalence of high/very high stress was 35% among DM patients. Age 30–40 years, working in professional jobs, and lack of physical activity were factors significantly associated with stress. The perceived major stress inducers were related to family, work, financial issues, and the disease itself. Conclusions: This study showed high levels of stress in more than one-third of DM patients. Potential solutions include regular, formal assessment of stress levels in the clinic, providing integrated counseling and psychological care for DM patients, and promoting physical activity. PMID:28217499

Short-term impact of a stress management and health promotion program on perceived stress, parental stress, health locus of control, and cortisol levels in parents of children and adolescents with diabetes type 1: a pilot randomized controlled trial.

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Tsiouli, Eleni; Pavlopoulos, Vassilis; Alexopoulos, Evangelos C; Chrousos, George; Darviri, Christina

2014-01-01

Parents of children and adolescents with diabetes type 1 (DT1) usually experience high stress levels, as they have to cope with multiple demands in their everyday life. Different complex interventions have been implemented, which sometimes have led to opposite results. The purpose of this study was to assess stress levels in parents of children and adolescents with DT1 and to evaluate the effectiveness of a stress management program (progressive muscle relaxation combined with diaphragmatic breathing) in reducing perceived and parenting stress, increasing internal locus of control, promoting healthy lifestyle, and normalizing cortisol levels. Randomized controlled trial. A total of 44 parents were randomly assigned to the intervention group (performing relaxation for eight weeks, n = 19) and control group (n = 25). Pre-post measurements included cortisol levels, lifestyle characteristics, perceived stress, perception of health, and parenting stress. A statistically significant decrease in perceived stress (from 27.21 to 19.00, P = .001), as well as in parenting stress (from 85.79 to 73.68, P = .003), was observed in the intervention group. A statistically significant difference was found in perceived stress between the two groups after the intervention (Dmean = 6.64, P = .010). No significant difference was revealed between or within the groups in cortisol levels. Significant improvement was reported by the subjects of the intervention group in various lifestyle parameters. Relaxation techniques seem to have a positive impact on stress and on various lifestyle factors in parents of children and adolescents with DT1. Future research on long-term benefits of an intervention program comprising of various relaxation schemes is warranted. Copyright © 2014 Elsevier Inc. All rights reserved.

The maximum ground level concentration of air pollutant and the effect of plume rise on concentration estimates

International Nuclear Information System (INIS)

Mayhoub, A.B.; Azzam, A.

1991-01-01

The emission of an air pollutant from an elevated point source according to Gaussian plume model has been presented. An elementary theoretical treatment for both the highest possible ground-level concentration and the downwind distance at which this maximum occurs for different stability classes has been constructed. The effective height release modification was taken into consideration. An illustrative case study, namely, the emission from the research reactor in Inchas, has been studied. The results of these analytical treatments and of the derived semi-empirical formulae are discussed and presented in few illustrative diagrams

Stress management skills, neuroimmune processes and fatigue levels in persons with chronic fatigue syndrome.

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Lattie, Emily G; Antoni, Michael H; Fletcher, Mary Ann; Penedo, Frank; Czaja, Sara; Lopez, Corina; Perdomo, Dolores; Sala, Andreina; Nair, Sankaran; Fu, Shih Hua; Klimas, Nancy

2012-08-01

Stressors and emotional distress responses impact chronic fatigue syndrome (CFS) symptoms, including fatigue. Having better stress management skills might mitigate fatigue by decreasing emotional distress. Because CFS patients comprise a heterogeneous population, we hypothesized that the role of stress management skills in decreasing fatigue may be most pronounced in the subgroup manifesting the greatest neuroimmune dysfunction. In total, 117 individuals with CFS provided blood and saliva samples, and self-report measures of emotional distress, perceived stress management skills (PSMS), and fatigue. Plasma interleukin-1-beta (IL-1β, IL-2, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α), and diurnal salivary cortisol were analyzed. We examined relations among PSMS, emotional distress, and fatigue in CFS patients who did and did not evidence neuroimmune abnormalities. Having greater PSMS related to less fatigue (p=.019) and emotional distress (pfatigue levels most strongly in CFS patients in the top tercile of IL-6, and emotional distress mediated the relationship between PSMS and fatigue most strongly in patients with the greatest circulating levels of IL-6 and a greater inflammatory (IL-6):anti-inflammatory (IL-10) cytokine ratio. CFS patients having greater PSMS show less emotional distress and fatigue, and the influence of stress management skills on distress and fatigue appear greatest among patients who have elevated IL-6 levels. These findings support the need for research examining the impact of stress management interventions in subgroups of CFS patients showing neuroimmune dysfunction. Copyright © 2012 Elsevier Inc. All rights reserved.

Similar cold stress induces sex-specific neuroendocrine and working memory responses.

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Solianik, Rima; Skurvydas, Albertas; Urboniene, Daiva; Eimantas, Nerijus; Daniuseviciute, Laura; Brazaitis, Marius

2015-01-01

Men have higher cold-induced neuroendocrine response than women; nevertheless, it is not known whether a different stress hormone rise elicits different effects on cognition during whole body cooling. The objective was to compare the effect of cold-induced neuroendocrine responses on the performance of working memory sensitive tasks between men and women. The cold stress continued until rectal temperature reached 35.5 degree C or for a maximum of 170 min. Working memory performance and stress hormone concentrations were monitored. During cold stress, body temperature variables dropped in all subjects (P < 0.001) and did not differ between sexes. Cold stress raised plasma epinephrine and serum cortisol levels only in men (P < 0.05). Cold stress adversely affected memory performance in men but not in women (P < 0.05). The present study indicated that similar moderate cold stress in men and women induces sex-specific neuroendocrine and working memory responses.

Burnout, Perceived Stress, and Job Satisfaction Among Trauma Nurses at a Level I Safety-Net Trauma Center.

Science.gov (United States)

Munnangi, Swapna; Dupiton, Lynore; Boutin, Anthony; Angus, L D George

Nurses are at the forefront of our health care delivery system and have been reported to exhibit a high level of burnout. Burnout and stress in trauma nurses at a safety-net hospital can negatively impact patient care. Safety-net hospitals are confronted with unique social, financial, as well as resource problems that can potentially make the work environment frustrating. The purpose of this study was to explore the levels of burnout, stress, and job satisfaction in nurses providing care to trauma patients at a Level I safety-net trauma center. A cross-sectional survey design was used to investigate principal factors including personal and professional demographics, burnout, perceived stress, and job satisfaction. Trauma nurses working at a Level I safety-net trauma center are stressed and exhibited moderate degree of burnout. The extent of emotional exhaustion experienced by the nurses varied with work location and was highest in surgical intensive care unit nurses. The level of job satisfaction in terms of opportunities for promotion differed significantly by race and the health status of the nurses. Satisfaction with coworkers was lowest in those nurses between the ages of 60-69 years. Female nurses were more satisfied with their coworkers than male nurses. In addition, the study revealed that significant relationships exist among perceived stress, burnout, and job satisfaction. Work environment significantly impacts burnout, job satisfaction, and perceived stress experienced by trauma nurses in a safety-net hospital. Nursing administration can make an effort to understand the levels of burnout and strategically improve work environment for trauma nurses in order to minimize stressors leading to attrition and enhance job satisfaction.

Applicability of initial stress measurement methods to Horonobe Siliceous rocks and initial stress state around Horonobe Underground Research Laboratory

International Nuclear Information System (INIS)

Sanada, Hiroyuki; Niunoya, Sumio; Matsui, Hiroya; Fujii, Yoshiaki

2009-01-01

Understanding initial stress condition in deep underground is important for such construction as rock cavern for geological disposal of HLW and underground power plant. Neogene sedimentary rock is widely distributed in Japan. There are only a few studies of initial stress measurement in Neogene sedimentary rock mass in Japan due to difficulty of measurement. Evaluation of initial stress condition around Horonobe Underground Research Laboratory Project was carried out in order to understand initial stress condition and applicability of AE, DSCA and hydraulic fracturing (HF) methods to Neogene sedimentary rock. Initial stress values obtained from AE method is smaller than overburden pressure due to time dependency of Kaizer effect. It would be difficult to use AE method as initial stress measurement method for Horonobe Siliceous rocks. Principal stress values by DSCA are similar to those by HF tests. Directions of maximum horizontal principal stresses are approximately in E-W and corresponded to HF results. In HF, rod type and wire-line type systems were compared. Workability of rod type was much better than wire-line type. However, re-opening pressure were not able to be precisely measured in case of rod type system due to the large compliance of the packers and rods. Horizontal maximum and minimum principal stresses increase linearly in HF results. Deviatoric stress is acting at shallow depth. Initial stress condition approaches hydrostatic condition with depth. Direction of maximum horizontal principal stress was in E-W direction which was similar to tectonic movement around Horonobe URL by triangular surveying. (author)

A Scaphoid Stress Fracture in a Female Collegiate-Level Shot-Putter and Review of the Literature

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Jessica M. Kohring

2016-01-01

Full Text Available Scaphoid stress fractures are rare injuries that have been described in young, high-level athletes who exhibit repetitive loading with the wrist in extension. We present a case of an occult scaphoid stress fracture in a 22-year-old female Division I collegiate shot-putter. She was successfully treated with immobilization in a thumb spica splint for 6 weeks. Loaded wrist extension activities can predispose certain high-level athletes to sustain scaphoid stress fractures, and a high index of suspicion in this patient population may aid prompt diagnosis and management of this rare injury.

Proximal and Distal Predictors of the Spider Monkey's Stress Levels in Fragmented Landscapes.

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José D Ordóñez-Gómez

Full Text Available The rapid loss, fragmentation and degradation of tropical forests threaten the survival of many animal species. However, the way in which these phenomena affect animal health has been poorly explored, thus limiting the design of appropriate conservation strategies. To address this, here we identified using linear mixed models the effect of proximal (diet, activity pattern, hunting and logging and distal (sum of the basal areas of fruiting-tree species [SBAFS], landscape forest cover and degree of forest fragmentation variables over fecal glucocorticoid metabolite (fGCM levels-hormones associated with animal health and fitness-of six groups of spider monkeys (Ateles geoffroyi inhabiting six landscapes with different spatial structures in Mexico. Proximal variables showed a stronger predictive power over fGCMs than distal. In this sense, increases in travel time, the occurrence of hunting, and reductions in rest time and fruit consumption resulted in higher fGCM levels. Regarding distal variables, increases in SBAFS were negatively related to fGCM levels, thus suggesting that food scarcity increases stress hormone levels. Nevertheless, contrary to theoretical expectations, spider monkeys living in smaller tracts of forest spent less time travelling, but the same time feeding on fruit as those in more forested areas. The lower net energy return associated with this combination of factors would explain why, contrary to theoretical expectations, increased forest cover was associated with increased levels of fGCMs in these groups. Our study shows that, at least in the short term, spider monkeys in fragmented landscapes do not always present higher levels of stress hormones compared to those inhabiting continuous forest, and the importance of preserving fruit sources and controlling hunting for reducing the levels of stress hormones in free ranging spider monkeys.

Cardiac damage associated with stress hyperglycaemia and acute coronary syndrome changes according to level of presenting blood glucose.

Science.gov (United States)

Al Jumaily, Talib; Rose'Meyer, Roselyn B; Sweeny, Amy; Jayasinghe, Rohan

2015-10-01

To determine the prevalence of stress hyperglycaemia in people presenting with acute coronary syndrome (ACS), and the relationships between admission glucose and cardiac damage, cardiovascular mortality and morbidity. In a prospective observational study people presenting with ACS at the Gold Coast Hospital had their admission glucose (AG) level tested to determine stress hyperglycaemia. A range of measurements supplemented this data including troponin levels, category of ACS and major adverse coronary events (MACEs) were obtained through hospital records and patient follow-up post-discharge. One hundred eighty-eight participants were recruited. The prevalence of stress hyperglycaemia in ACS was 44% with 31% having a previous diagnosis of type 2 diabetes and 7.7% had undiagnosed diabetes. The stress hyperglycaemic group had a significantly higher median troponin levels compared to participants with normal blood glucose levels on admission (pglucose group (>15 mmol/L) had troponin levels similar to people presenting with normal blood glucose levels and ACS (p>0.05). Cardiac necrosis as measured by troponin levels is significantly increased in people with ACS and stress hyperglycaemia. This study found that one in four participants presenting with ACS and an admission glucose of >7.0 had no previous diagnosis for diabetes. Consistently ordering HbA1C testing on patients with high AG can enable earlier diagnosis and treatment of diabetes. Copyright © 2015. Published by Elsevier Ireland Ltd.

Effect of advance meditation program on electrocardiogram, blood pressure, and stress level in young healthy adults

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M Sharma

2017-01-01

Conclusion: AMP has its positive effects on ECG, blood pressure, and stress level. Thus, it can be considered as one of the important nonpharmacological methods for prevention of stress, anxiety, and cardiovascular diseases.

Effects of fasting on maximum thermogenesis in temperature-acclimated rats

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Wang, L. C. H.

1981-09-01

To further investigate the limiting effect of substrates on maximum thermogenesis in acute cold exposure, the present study examined the prevalence of this effect at different thermogenic capabilities consequent to cold- or warm-acclimation. Male Sprague-Dawley rats (n=11) were acclimated to 6, 16 and 26‡C, in succession, their thermogenic capabilities after each acclimation temperature were measured under helium-oxygen (21% oxygen, balance helium) at -10‡C after overnight fasting or feeding. Regardless of feeding conditions, both maximum and total heat production were significantly greater in 6>16>26‡C-acclimated conditions. In the fed state, the total heat production was significantly greater than that in the fasted state at all acclimating temperatures but the maximum thermogenesis was significant greater only in the 6 and 16‡C-acclimated states. The results indicate that the limiting effect of substrates on maximum and total thermogenesis is independent of the magnitude of thermogenic capability, suggesting a substrate-dependent component in restricting the effective expression of existing aerobic metabolic capability even under severe stress.

Minimum and Maximum Potential Contributions to Future Sea Level Rise from Polar Ice Sheets

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Deconto, R. M.; Pollard, D.

2017-12-01

New climate and ice-sheet modeling, calibrated to past changes in sea-level, is painting a stark picture of the future fate of the great polar ice sheets if greenhouse gas emissions continue unabated. This is especially true for Antarctica, where a substantial fraction of the ice sheet rests on bedrock more than 500-meters below sea level. Here, we explore the sensitivity of the polar ice sheets to a warming atmosphere and ocean under a range of future greenhouse gas emissions scenarios. The ice sheet-climate-ocean model used here considers time-evolving changes in surface mass balance and sub-ice oceanic melting, ice deformation, grounding line retreat on reverse-sloped bedrock (Marine Ice Sheet Instability), and newly added processes including hydrofracturing of ice shelves in response to surface meltwater and rain, and structural collapse of thick, marine-terminating ice margins with tall ice-cliff faces (Marine Ice Cliff Instability). The simulations improve on previous work by using 1) improved atmospheric forcing from a Regional Climate Model and 2) a much wider range of model physical parameters within the bounds of modern observations of ice dynamical processes (particularly calving rates) and paleo constraints on past ice-sheet response to warming. Approaches to more precisely define the climatic thresholds capable of triggering rapid and potentially irreversible ice-sheet retreat are also discussed, as is the potential for aggressive mitigation strategies like those discussed at the 2015 Paris Climate Conference (COP21) to substantially reduce the risk of extreme sea-level rise. These results, including physics that consider both ice deformation (creep) and calving (mechanical failure of marine terminating ice) expand on previously estimated limits of maximum rates of future sea level rise based solely on kinematic constraints of glacier flow. At the high end, the new results show the potential for more than 2m of global mean sea level rise by 2100

Interpretation of the Haestholmen in situ state of stress based on core damage observations

International Nuclear Information System (INIS)

Hakala, M.

2000-01-01

At the Haestholmen investigation site, direct in situ stress measurements, overcoring and hydraulic fracturing have been unsuccessful because of ring disking and horizontal hydraulic fracturing. Prior to this study, a detailed study on both core disking and ring disking was made, and based on those results an in situ state of stress interpretation method was developed. In this work this method is applied to the Haestholmen site. The interpretation is based on disk fracture type, spacing and shape. Also, the Hoek-Brown strength envelope and Poisson's ratio of intact rock are needed. The interpretation result is most reliable if both core disking and ring disking information at the same depth levels is available. A detailed core logging showed that ring disking is systematic below the -365 m level in the vertical overcoring stress measurement hole, HH-KR6. On the other hand, no representative core disking exists except for two points in two differently oriented subvertical boreholes HH-KR2 and HHKR7. Because the interpretation has to be based on ring disking only, upper and lower estimates for the vertical stress were set. These were gravitational and 67% of gravitational. Furthermore, the in situ stress state was assumed to be in horizontal and vertical planes, because the disking in vertical borehole HH-KR6 was not inclined. The interpretation resulted in a good estimate for the major horizontal stress but none of the horizontal stress rations ( 0.25, 0.5, 0.75 and 1.0 ) or vertical stress assumptions studied are clearly more probable the others. At the 500 m level the resulting maximum horizontal stress is 41 MPa. If a linear fit through the zero depth and zero stress point is applied, the maximum horizontal stress gradient is 0.0818 z MPa/m with a standard deviation between 5 and 12 per cent. The orientation of the major horizontal stress is 108 with standard deviation of 21 degrees. The interpreted major horizontal stress state also indicated that systematic

Experimental verification of the imposing principle for maximum permissible levels of multicolor laser radiation

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Ivashin V.A.

2013-12-01

Full Text Available Aims. The study presents the results of experimental research to verify the principle overlay for maximum permissible levels (MPL of multicolor laser radiation single exposure on eyes. This principle of the independence of the effects of radiation with each wavelength (the imposing principle, was founded and generalized to a wide range of exposure conditions. Experimental verification of this approach in relation to the impact of laser radiation on tissue fundus of an eye, as shows the analysis of the literature was not carried out. Material and methods. Was used in the experimental laser generating radiation with wavelengths: Л1 =0,532 microns, A2=0,556to 0,562 microns and A3=0,619to 0,621 urn. Experiments were carried out on eyes of rabbits with evenly pigmented eye bottom. Results. At comparison of results of processing of the experimental data with the calculated data it is shown that these levels are close by their parameters. Conclusions. For the first time in the Russian Federation had been performed experimental studies on the validity of multi-colored laser radiation on the organ of vision. In view of the objective coincidence of the experimental data with the calculated data, we can conclude that the mathematical formulas work.

Adult age differences in prospective memory in the laboratory: are they related to higher stress levels in the elderly?

Science.gov (United States)

Ihle, Andreas; Kliegel, Matthias; Hering, Alexandra; Ballhausen, Nicola; Lagner, Prune; Benusch, Julia; Cichon, Anja; Zergiebel, Annekathrin; Oris, Michel; Schnitzspahn, Katharina M

2014-01-01

To explain age deficits found in laboratory-based prospective memory (PM) tasks, it has recently been suggested that the testing situation per se may be more stressful for older adults, thereby impairing their performance. To test this assumption, subjective and physiological stress levels were assessed at several times during the experiment in 33 younger and 29 older adults. In addition, half of participants were randomized in a condition where they completed a relaxation intervention before performing a time-based PM task. Results confirmed the age deficit in laboratory PM. Subjective and physiological stress levels showed no age difference and no detrimental association with PM. The intervention successfully reduced stress levels in both age groups but had no effect on PM or the age deficit. In conclusion, data suggest that age deficits usually observed in laboratory PM may not be due to higher stress levels in the older adults.

The Benefits of Leisure Stress.

Science.gov (United States)

Mitchell, Jr., Richard G.

1982-01-01

Leisure bereft of all stress is action without purpose. Maximum motivation and gratification are achieved when a balance is achieved between abilities and responsibilities. Stress is an essential leisure ingredient that provides meaning and clarity to social experience. (CJ)

Environmental stress, TRH and lactation effects on plasma growth hormone of cattle

International Nuclear Information System (INIS)

Johnson, H.D.; DeDios, O.; Lippincott, A.C.

1976-01-01

Plasma growth hormone (GH) levels of cattle are influenced by numerous environmental and metabolic factors. Acute heat stress increases GH threefold with maximum value at 30 minutes post-exposure. TRH infusion also shows a threefold increase as early as 2 minutes post-infusion but with a continual elevation for approximately 20 minutes. Longer-term environmental heat stress exposure, as occurs in tropics and the summer season, lowers plasma GH of cattle. GH levels in high-producing, lactating cows are greater than in low producers. In summary, plasma increases in levels of GH immediately reflect the stressor effects on cattle, presumably through involvement of TRH release. Long-term heat stressors, such as seasonal or tropic acclimatization, lowers GH of lactating cattle. (author)

Study of Foeniculum vulgare (Fennel Seed Extract Effects on Serum Level of Oxidative Stress

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Sadeghpour Nahid

2015-04-01

Full Text Available Objective: The Foeniculum vulgare (FVE, known as fennel, has a long history of herbal uses as both food and medicine. The seed of this plant has been used to promote menstruation, alleviate the symptoms of female climacteric, and increase the number of ovarian follicles. The aim of this study was to evaluate the fennel extract effects on serum level of oxidative stress in female mice. Materials and Methods: Totally, 28 virgin female albino mice were divided into four groups (n = 7. Groups 1 and 2 (experimental groups were administered FVE at 100 and at a concentration of 100 and 200 mg/kg for 5 days, interaperitoneally. Group 3 (negative control received ethanol and Group 4 (positive control received normal saline. Animals were scarified at 6th day, sera were collected and the level of oxidative stress was determination of using total antioxidant status kit. Results: Data analysis revealed that there is a significant difference in the mean level of serum oxidative stress between four different groups. P value in experimental groups compared to the control group was (P < 0.0001. Conclusion: Fennel extract can decrease the serum level of oxidative factors in female mice; it can be introduced as a novel medicine for treatment of infertility

Stress accumulation and release at complex transform plate boundaries

Energy Technology Data Exchange (ETDEWEB)

Verdonck, D.; Furlong, K.P. (Pennsylvania State Univ., University Park (United States))

1992-10-01

Finite element methods are used to model the dynamics of deformation along complex transform plate boundaries, specifically the San Andreas fault system, California. Effects of mantle rheology and fault geometry on the stress buildup and release are investigated. No prior knowledge of the earthquake cycle time or amount of fault slip is assumed that the results suggest that the San Andreas fault slips at low shear stress (about 15 MPa). Although the maximum stress on the fault is 15 MPa, models with an upper mantle shear zone deforming entirely by dislocation creep accumulate stresses that exceed 100 MPa, a stress level high enough to drive localized dynamic recrystallization and a shift in dominant deformation mechanism to diffusion creep. Models in which the mantle shear zone deform locally by diffusion creep reach a dynamic steady state where lithospheric shear stresses never exceed the specified fault stress anywhere in the model and indicate that the strength of the upper mantle is an important parameter in the dynamics of plate boundary deformation. 17 refs.

Chronic Stress Reduces Nectin-1 mRNA Levels and Disrupts Dendritic Spine Plasticity in the Adult Mouse Perirhinal Cortex

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Qian Gong

2018-03-01

Full Text Available In adulthood, chronic exposure to stressful experiences disrupts synaptic plasticity and cognitive function. Previous studies have shown that perirhinal cortex-dependent object recognition memory is impaired by chronic stress. However, the stress effects on molecular expression and structural plasticity in the perirhinal cortex remain unclear. In this study, we applied the chronic social defeat stress (CSDS paradigm and measured the mRNA levels of nectin-1, nectin-3 and neurexin-1, three synaptic cell adhesion molecules (CAMs implicated in the adverse stress effects, in the perirhinal cortex of wild-type (WT and conditional forebrain corticotropin-releasing hormone receptor 1 conditional knockout (CRHR1-CKO mice. Chronic stress reduced perirhinal nectin-1 mRNA levels in WT but not CRHR1-CKO mice. In conditional forebrain corticotropin-releasing hormone conditional overexpression (CRH-COE mice, perirhinal nectin-1 mRNA levels were also reduced, indicating that chronic stress modulates nectin-1 expression through the CRH-CRHR1 system. Moreover, chronic stress altered dendritic spine morphology in the main apical dendrites and reduced spine density in the oblique apical dendrites of perirhinal layer V pyramidal neurons. Our data suggest that chronic stress disrupts cell adhesion and dendritic spine plasticity in perirhinal neurons, which may contribute to stress-induced impairments of perirhinal cortex-dependent memory.

The stress-vulnerability model how does stress impact on mental illness at the level of the brain and what are the consequences?

Science.gov (United States)

Goh, Cindy; Agius, Mark

2010-06-01

The stress -vulnerability model (Zubin et al. 1977) is an extremely useful model for identifying and treating relapses of mental illness. We accept that human persons carry genetic and other predisposition to mental illness. However, the question arises as to how stress impacts on a person in order to cause mental illness to develop. Furthermore there arises the issue as to what other effects such stress has on the human body beyond the human brain. Our aim was to research and integrate the current literature in order to establish how stress impacts on the brain at the cellular level, and to establish whether there are other consequences for the human body brought about by the impact of stress on the human brain. Literature Search, using pubmed. We have identified much literature on how stress affects biological mechanisms within the brain, and how it relates to biological vulnerabilities carried by different individuals. We have identified communalities in how the interplay between stress and vulnerability occurs in different disease processes.

Recommendation of maximum allowable noise levels for offshore wind power systems; Empfehlung von Laermschutzwerten bei der Errichtung von Offshore-Windenergieanlagen (OWEA)

Energy Technology Data Exchange (ETDEWEB)

Werner, Stefanie [Umweltbundesamt, Dessau-Rosslau (Germany). Fachgebiet II 2.3

2011-05-15

When offshore wind farms are constructed, every single pile is hammered into the sediment by a hydraulic hammer. Noise levels at Horns Reef wind farm were in the range of 235 dB. The noise may cause damage to the auditory system of marine mammals. The Federal Environmental Office therefore recommends the definition of maximum permissible noise levels. Further, care should be taken that no marine mammals are found in the immediate vicinity of the construction site. (AKB)

Particle Swarm Optimization Based of the Maximum Photovoltaic ...

African Journals Online (AJOL)

Photovoltaic electricity is seen as an important source of renewable energy. The photovoltaic array is an unstable source of power since the peak power point depends on the temperature and the irradiation level. A maximum peak power point tracking is then necessary for maximum efficiency. In this work, a Particle Swarm ...

Stress response in medically important Mucorales.

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Singh, Pankaj; Paul, Saikat; Shivaprakash, M Rudramurthy; Chakrabarti, Arunaloke; Ghosh, Anup K

2016-10-01

Mucorales are saprobes, ubiquitously distributed and able to infect a heterogeneous population of human hosts. The fungi require robust stress responses to survive in human host. We tested the growth of Mucorales in the presence of different abiotic stress. Eight pathogenic species of Mucorales, including Rhizopus arrhizus, Rhizopus microsporus, Rhizomucor pusillus, Apophysomyces elegans, Licthemia corymbifera, Cunninghamella bertholletiae, Syncephalastrum racemosum and Mucor racemosus, were exposed to different stress inducers: osmotic (sodium chloride and d-sorbitol), oxidative (hydrogen peroxide and menadione), pH, cell wall and metal ions (Cu, Zn, Fe and Mg). Wide variation in stress responses was noted: R. arrhizus showed maximum resistance to both osmotic and oxidative stresses, whereas R. pusillus and M. indicus were relatively sensitive. Rhizopus arrhizus and R. microsporus showed maximum resistance to alkaline pH, whereas C. bertholletiae, L. corymbifera, M. racemosus and A. elegans were resistant to acidic pH. Maximum tolerance was noted in R. microsporus to Cu, R. microsporus and R. arrhizus to Fe and C. bertholletiae to Zn. In contrast, L. corymbifera, A. elegans and M. indicus were sensitive to Cu, Zn and Fe respectively. In conclusion, R. arrhizus showed high stress tolerance in comparison to other species of Mucorales, and this could be the possible reason for high pathogenic potential of this fungi. © 2016 Blackwell Verlag GmbH.

Validation of Analytical Damping Ratio by Fatigue Stress Limit

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Foong, Faruq Muhammad; Chung Ket, Thein; Beng Lee, Ooi; Aziz, Abdul Rashid Abdul

2018-03-01

The optimisation process of a vibration energy harvester is usually restricted to experimental approaches due to the lack of an analytical equation to describe the damping of a system. This study derives an analytical equation, which describes the first mode damping ratio of a clamp-free cantilever beam under harmonic base excitation by combining the transverse equation of motion of the beam with the damping-stress equation. This equation, as opposed to other common damping determination methods, is independent of experimental inputs or finite element simulations and can be solved using a simple iterative convergence method. The derived equation was determined to be correct for cases when the maximum bending stress in the beam is below the fatigue limit stress of the beam. However, an increasing trend in the error between the experiment and the analytical results were observed at high stress levels. Hence, the fatigue limit stress was used as a parameter to define the validity of the analytical equation.

Chronic stress associated with hypercaloric diet changes the hippocampal BDNF levels in male Wistar rats.

Science.gov (United States)

Macedo, I C; Rozisky, J R; Oliveira, C; Oliveira, C M; Laste, G; Nonose, Y; Santos, V S; Marques, P R; Ribeiro, M F M; Caumo, W; Torres, I L S

2015-06-01

Chronic stress, whether associated with obesity or not, leads to different neuroendocrine and psychological changes. Obesity or being overweight has become one of the most serious worldwide public health problems. Additionally, it is related to a substantial increase in daily energy intake, which results in substituting nutritionally adequate meals for snacks. This metabolic disorder can lead to morbidity, mortality, and reduced quality of life. On the other hand, brain-derived neurotrophic factor (BDNF) is widely expressed in all brain regions, particularly in the hypothalamus, where it has important effects on neuroprotection, synaptic plasticity, mammalian food intake-behavior, and energy metabolism. BDNF is involved in many activities modulated by the hypothalamic-pituitary-adrenal (HPA) axis. Therefore, this study aims to evaluate the effect of obesity associated with chronic stress on the BDNF central levels of rats. Obesity was controlled by analyzing the animals' caloric intake and changes in body weight. As a stress parameter, we analyzed the relative adrenal gland weight. We found that exposure to chronic restraint stress during 12 weeks increases the adrenal gland weight, decreases the BDNF levels in the hippocampus and is associated with a decrease in the calorie and sucrose intake, characterizing anhedonia. These effects can be related stress, a phenomenon that induces depression-like behavior. On the other hand, the rats that received the hypercaloric diet had an increase in calorie intake and became obese, which was associated with a decrease in hypothalamus BDNF levels. Copyright © 2015. Published by Elsevier Ltd.

Ecological interactions affecting population-level responses to chemical stress in Mesocyclops leuckarti.

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Kulkarni, Devdutt; Hommen, Udo; Schäffer, Andreas; Preuss, Thomas G

2014-10-01

Higher tiers of ecological risk assessment (ERA) consider population and community-level endpoints. At the population level, the phenomenon of density dependence is one of the most important ecological processes that influence population dynamics. In this study, we investigated how different mechanisms of density dependence would influence population-level ERA of the cyclopoid copepod Mesocyclops leuckarti under toxicant exposure. We used a combined approach of laboratory experiments and individual-based modelling. An individual-based model was developed for M. leuckarti to simulate population dynamics under triphenyltin exposure based on individual-level ecological and toxicological data from laboratory experiments. The study primarily aimed to-(1) determine which life-cycle processes, based on feeding strategies, are most significant in determining density dependence (2) explore how these mechanisms of density dependence affect extrapolation from individual-level effects to the population level under toxicant exposure. Model simulations showed that cannibalism of nauplii that were already stressed by TPT exposure contributed to synergistic effects of biotic and abiotic factors and led to a twofold stress being exerted on the nauplii, thereby resulting in a higher population vulnerability compared to the scenario without cannibalism. Our results suggest that in population-level risk assessment, it is easy to underestimate toxicity unless underlying ecological interactions including mechanisms of population-level density regulation are considered. This study is an example of how a combined approach of experiments and mechanistic modelling can lead to a thorough understanding of ecological processes in ecotoxicology and enable a more realistic ERA. Copyright © 2014 Elsevier Ltd. All rights reserved.

Student-Life Stress Level and its Related Factors among Medical Students of Hamadan University of Medical Sciences in 2015

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Roya Nikanjam

2016-03-01

Full Text Available Background and Objectives: Student-life stress can lead to various negative consequences such as physical illness, mental disorders or exhaustion. The present study was conducted to evaluate the level of student life stress and its related factors among medical students of Hamadan University of Medical Sciences. Materials and Methods: This cross-sectional study applied multistage random sampling to select 500university students at Hamadan University of Medical Sciences during 2015. The data collection tool used in this study was a self-report questionnaire containing two parts: a section on subjects' demographic details and another section for Student-Life Stress Inventory (SLSI. Data were analyzed in SPSS20-using descriptive and inferential statistics, such as independent t-test, Pearson’s correlation test and one-way ANOVA. Results: This study revealed that %57of the students had moderate levels of stress. The most important stressors included self-impose and pressure, and also the most important reactions to stressors included cognitive appraisal and emotional reactions, respectively. There was a significant association between exam stressors and branch, educational level, and mother's and father's education level (P< 0.05. Conclusions: According to the high level of stress in students and the recognition of demographic factors, effective educational interventions can be conducted to reduce stress.

Exploratory Study on the Impact of Information on Performance Psychology on Stress and Anxiety Levels of Brazilian Music Performers

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Sonia Ray

2016-12-01

Full Text Available This paper examines the impact of information on psychology of music on Stress and Anxiety Levels of Brazilian students of music performance, both undergraduate and graduate, and cross information on their levels of stress and anxiety. It includes an investigation on curricular programs of Brazilian public universities based on previous investigation by the authors (RAY; et al, 2011. The main goals: 1 to investigate how much information Brazilian music performance students has access to access during their courses; and 2 to identify potential indicators of the impact this information may have on the levels of stress and anxiety in the performances of these students; Methodology:  Students from six Brazilian public universities were requested to fill out three forms: the Kenny Music Performance Anxiety Inventory (K-MPAI; the Inventory of Stress Symptoms LIPP and an additional form that investigated the participants routine for preparation to performance. Results: information on music performance psychology is only presented privately at teacher’s discretion. As compulsory classes have not been included in the curriculum, it was not possible to infer results on this subject. More than half of the participants (51,72% don’t present stress condition. Almost half of them (48,27% have some level of stress. All participants fit within some level of anxiety.

Experimental Investigation of Principal Residual Stress and Fatigue Performance for Turned Nickel-Based Superalloy Inconel 718.

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Hua, Yang; Liu, Zhanqiang

2018-05-24

Residual stresses of turned Inconel 718 surface along its axial and circumferential directions affect the fatigue performance of machined components. However, it has not been clear that the axial and circumferential directions are the principle residual stress direction. The direction of the maximum principal residual stress is crucial for the machined component service life. The present work aims to focuses on determining the direction and magnitude of principal residual stress and investigating its influence on fatigue performance of turned Inconel 718. The turning experimental results show that the principal residual stress magnitude is much higher than surface residual stress. In addition, both the principal residual stress and surface residual stress increase significantly as the feed rate increases. The fatigue test results show that the direction of the maximum principal residual stress increased by 7.4%, while the fatigue life decreased by 39.4%. The maximum principal residual stress magnitude diminished by 17.9%, whereas the fatigue life increased by 83.6%. The maximum principal residual stress has a preponderant influence on fatigue performance as compared to the surface residual stress. The maximum principal residual stress can be considered as a prime indicator for evaluation of the residual stress influence on fatigue performance of turned Inconel 718.

Experimental Investigation of Principal Residual Stress and Fatigue Performance for Turned Nickel-Based Superalloy Inconel 718

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Yang Hua

2018-05-01

Full Text Available Residual stresses of turned Inconel 718 surface along its axial and circumferential directions affect the fatigue performance of machined components. However, it has not been clear that the axial and circumferential directions are the principle residual stress direction. The direction of the maximum principal residual stress is crucial for the machined component service life. The present work aims to focuses on determining the direction and magnitude of principal residual stress and investigating its influence on fatigue performance of turned Inconel 718. The turning experimental results show that the principal residual stress magnitude is much higher than surface residual stress. In addition, both the principal residual stress and surface residual stress increase significantly as the feed rate increases. The fatigue test results show that the direction of the maximum principal residual stress increased by 7.4%, while the fatigue life decreased by 39.4%. The maximum principal residual stress magnitude diminished by 17.9%, whereas the fatigue life increased by 83.6%. The maximum principal residual stress has a preponderant influence on fatigue performance as compared to the surface residual stress. The maximum principal residual stress can be considered as a prime indicator for evaluation of the residual stress influence on fatigue performance of turned Inconel 718.

Oxidative stress and decreased thiol level in patients with migraine: cross-sectional study.

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Eren, Yasemin; Dirik, Ebru; Neşelioğlu, Salim; Erel, Özcan

2015-12-01

Although migraine is a neurological disorder known since long, its physiopathology remains unclear. Recent studies suggest that migraine is associated with oxidative stress; however, they report divergent results. The aim of the present study was to evaluate total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and serum thiol level in migraine patients with or without aura. The study group consisted of 141 migraine patients. The control group included 70 healthy subjects. TAS, TOS, OSI were evaluated using a method developed by Erel. Serum thiol level was measured using the Hu method. No difference was found in TAS, TOS, OSI between the patients and controls. The level of thiol was significantly lower in patients than in controls. Negative correlations were detected between thiol level and Migraine Disability Assessment score in patients. Although TAS, TOS, and OSI were similar to those of the control group, serum thiol level, an important marker of antioxidant capacity, was significantly lower in migraines compared with controls, and caused more serious disability. Novel treatment approaches may be developed based on these data, and compounds containing thiol, such as alpha lipoic acid and N-acetyl cysteine, may be used in prophylaxis.

Initial stress and nonlinear material behavior in patient-specific AAA wall stress analysis

NARCIS (Netherlands)

Speelman, L.; Bosboom, E.M.H.; Schurink, G.W.H.; Buth, J.; Breeuwer, M.; Jacobs, M.J.; Vosse, van de F.N.

2009-01-01

Rupture risk estimation of abdominal aortic aneurysms (AAA) is currently based on the maximum diameter of the AAA. A more critical approach is based on AAA wall stress analysis. For that, in most cases, the AAA geometry is obtained from CT-data and treated as a stress free geometry. However, during

Acute Oxidative Effect and Muscle Damage after a Maximum 4 Min Test in High Performance Athletes.

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Heros Ribeiro Ferreira

Full Text Available The purpose of this investigation was to determine lipid peroxidation markers, physiological stress and muscle damage in elite kayakers in response to a maximum 4-min kayak ergometer test (KE test, and possible correlations with individual 1000m kayaking performances. The sample consisted of twenty-three adult male and nine adult female elite kayakers, with more than three years' experience in international events, who voluntarily took part in this study. The subjects performed a 10-min warm-up, followed by a 2-min passive interval, before starting the test itself, which consisted of a maximum 4-min work paddling on an ergometer; right after the end of the test, an 8 ml blood sample was collected for analysis. 72 hours after the test, all athletes took part in an official race, when then it was possible to check their performance in the on site K1 1000m test (P1000m. The results showed that all lipoproteins and hematological parameters tested presented a significant difference (p≤0.05 after exercise for both genders. In addition, parameters related to muscle damage such as lactate dehydrogenase (LDH and creatine kinase (CK presented significant differences after stress. Uric acid presented an inverse correlation with the performance (r = -0.76, while CK presented a positive correlation (r = 0.46 with it. Based on these results, it was possible to verify muscle damage and the level of oxidative stress caused by indoor training with specific ergometers for speed kayaking, highlighting the importance of analyzing and getting to know the physiological responses to this type of training, in order to provide information to coaches and optimize athletic performance.

Stress analysis of thermal sprayed coatings using a semi-destructive hole-drilling strain gauge method

International Nuclear Information System (INIS)

Dolhof, V.; Musil, J.; Cepera, M.; Zeman, J.

1995-01-01

Residual stress is an important parameter in coating technology since it often relates to the maximum coating thickness which can be deposited without spallation, and this applies to coatings produced by different thermal spray and thin film technologies. Indeed, the mechanisms by which residual stress is built up or locked into a coating depends markedly on the deposition process and coating structure (growth structure, phase composition) in the same way too. Methods for determining residual stresses in materials include both destructive and non-destructive methods. This contribution describes semi-destructive hole-drilling strain gauge method modified for measurement of residual stresses in thermal sprayed coatings. This method of stress analysis was used for determination of stress levels in thermal sprayed WC-17% Co coatings onto 13% Cr steel substrates. Results show that deposition conditions and final coating structure influence directly the residual stress level in the coatings. It is proved that semi-destructive hole-tube drilling measurement is effective reproducible method of coating stress analysis and good solution for optimization of deposition process

Mathematical model to determine the surface stress acting on the tooth of gear

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Hinojosa-Torres J.

2010-01-01

Full Text Available Surface stress on the surface contact of gear tooth calculated by the Buckingham equation constitutes the basis for The American Gear Manufacturers Association (AGMA pitting resistance formula, which is based on a normal stress that does not cause failure since the yielding in contact problems is caused by shear stresses. An alternative expression based on the maximum-shear-stress is proposed in this paper. The new expression is obtained by using the maximum-shear-stress distribution and the Tresca failure criteria in order to know the maximum-shear-stress value and its location beneath the contact surface. Remarkable differences between the results using the proposed equation and those when the AGMA equation is applied are found.

Measurement of the uniaxial mechanical properties of rat skin using different stress-strain definitions.

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Karimi, A; Navidbakhsh, M

2015-05-01

The mechanical properties of skin tissue may vary according to the anatomical locations of a body. There are different stress-strain definitions to measure the mechanical properties of skin tissue. However, there is no agreement as to which stress-strain definition should be implemented to measure the mechanical properties of skin at different anatomical locations. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) are employed to determine the mechanical properties of skin tissue at back and abdomen locations of a rat body. The back and abdomen skins of eight rats are excised and subjected to a series of tensile tests. The elastic modulus, maximum stress, and strain of skin tissues are measured using three stress definitions and four strain definitions. The results show that the effect of varying the stress definition on the maximum stress measurements of the back skin is significant but not when calculating the elastic modulus and maximum strain. No significant effects are observed on the elastic modulus, maximum stress, and strain measurements of abdomen skin by varying the stress definition. In the true stress-strain diagram, the maximum stress (20%), and elastic modulus (35%) of back skin are significantly higher than that of abdomen skin. The true stress-strain definition is favored to measure the mechanical properties of skin tissue since it gives more accurate measurements of the skin's response using the instantaneous values. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Residual stresses evolution in hardening, cold drawn or shot-peening carbon steel as a function of the heating temperature

International Nuclear Information System (INIS)

Vannes, A.-B.; Parisot, Alain; Fougeres, Roger; Theolier, Maurice

1977-01-01

Residual stress variations are studied in hardening, cold-drawn, shot-peening carbon steel samples as a function of heating temperature or the tempering one. For temperatures between 100 0 C and 250 0 C, a relative maximum is observed for the mean level of the residual stresses. These results are explained on the basis of two antagonistic mechanisms: restoration and ageing [fr

Stress Levels of Kuwaiti Mothers of Children with SLD: Does Work and Educational Status Matter?

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Alazemi, Saad S.; Hadadian, Azar; Merbler, John B.; Wang, Cen

2015-01-01

Existing research literature indicates that parents of children with disabilities have higher stress. The purpose of this study was to examine differences in stress levels between mothers in relation to their children with specific learning disabilities (SLD). A sub sample of 91 mothers participated in the study. The outcome of the research…

Hair cortisol levels, perceived stress and body mass index in women and children living in socioeconomically disadvantaged neighborhoods: the READI study.

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Olstad, Dana Lee; Ball, Kylie; Wright, Craig; Abbott, Gavin; Brown, Erin; Turner, Anne Isabella

2016-01-01

Disadvantaged communities provide adverse psychosocial exposures that have been linked to high levels of stress, and this may provide one explanatory pathway linking socioeconomic disadvantage to obesity. This study used hair cortisol analysis to quantify associations between stress and body mass index (BMI), and between hair cortisol and perceived psychological stress levels, in women and children living in socioeconomically disadvantaged neighborhoods. Participants were a volunteer sample of 70 women from the Resilience for Eating and Activity Despite Inequality study, including 30 maternal-child pairs. Women self-reported body weight, height and perceived psychological stress using the Perceived Stress Scale (PSS), and provided hair samples for themselves and their child. Children's body weight and height were measured. Following extraction, hair cortisol levels were measured using enzyme-linked immunosorbent assay. Multiple linear regression models examined associations between stress and BMI, and between hair cortisol and perceived stress levels in women and children. Women's hair cortisol levels were not associated with their BMI or PSS scores. Women's PSS scores were positively associated with their BMI (p = 0.015). Within maternal-child pairs, mothers and children's hair cortisol levels were strongly positively associated (p = 0.006). Maternal hair cortisol levels and PSS scores were unrelated to their child's zBMI. Children's hair cortisol levels were not associated with their zBMI or with their mother's PSS score. Findings suggest that cortisol-based and perceived psychological measures of stress may be distinct among women and children living in disadvantaged neighborhoods. Perceived psychological measures may be more important predictors of weight-related risk.

Child Maltreatment Trauma, Posttraumatic Stress Disorder, and Cortisol Levels in Women: A Literature Review.

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Li, Yang; Seng, Julia S

Studies of the relationship between cortisol and posttraumatic stress disorder (PTSD) have had inconsistent results. Gender, trauma type, and age at trauma exposure may explain the inconsistencies. The objective of the review was to examine cortisol levels in relation to PTSD in women with a history of child maltreatment trauma. A review of literature found 13 articles eligible for inclusion. Despite limiting focus to the relatively homogeneous population, the patterns of associations between PTSD and cortisol levels were still inconsistent. The reasons for the inconsistencies likely include highly varied methods across studies, small convenience samples, and unmeasured neuroendocrine hormones that may be stronger predictors of PTSD. The review does not point to a clear bio-behavioral target for psychiatric nursing intervention. It is important to continue to address the developmental and clinical stress response aspects of child maltreatment trauma-related PTSD without assuming that these stress responses are hypothalamic-pituitary-adrenal-axis driven.

Intervarietal variations in various oxidative stress markers and antioxidant potential of finger millet (Eleusine coracana) subjected to drought stress.

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Bartwal, Arti; Pande, Anjali; Sharma, Priyadarshini; Arora, Sandeep

2016-07-01

Drought is a major form of abiotic stress leading to lower crop productivity. Experiment was carried out for selecting the most tolerant genotype among six different genotypes of finger millet under drought stress. Seeds of six finger millet genotypes were sown in pots and grown for 35 days. After this period, drought was induced by withholding watering for stressed plants while control plants were watered regularly for comparison. Among all six different varieties of finger millet screened (PR202, PES400, PRM6107, VL283, VL328 and VL149) under varying intensities of drought stress,PRM6107 and PR202 showed highest stress tolerance by limiting excessive accumulation of reactive oxygen species (ROS) through activation of ROS scavenging antioxidative enzymes. A 200% increase in ascorbate content was recorded in PRM6107 and PR202, while in other varieties limited increase in ascorbate content was observed. Maximum decrease in chlorophyll content was observed in VL328 (83%) while least drop was observed in VL149 (65%). Relative water content indicated that PR202 was able to retain maximum water content under stress, as it recorded least drop in relative water content (55%), contributing to its better survival under stress. In conclusion finger millet genotypes PRM6107 and PR202 possessed maximum drought tolerance potential and thus may be used for allele mining of drought tolerant genes, which can further be employed for the development of more drought stress tolerant staple crops using biotechnological approach.

Evaluation of the melatonin and oxidative stress markers level in serum of fertile and infertile women

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Sara Soleimani Rad

2015-07-01

Full Text Available Background: Infertility is defined as the inability to achieve the pregnancy within a year of unprotected intercourse. Infertility is a complex issue and different factors such as stress oxidative can be involved in this problem. So, any attempt to neutralize oxidative stress would be helpful in the treatment of infertility. Melatonin is a known scavenger of free radicals. Objective: The aim of our study was to evaluate the level of melatonin and its correlation with oxidative biomarkers in fertile and infertile women. Materials and Methods: The participants including fertile and infertile women were divided into two groups of 30 people. Blood sampling was performed and sera were collected. The level of Malondialdehyde (MDA, total antioxidant capacity (TAC and melatonin were detected. Data were analyzed using T-test and their correlation was assessed using Spearman test. Results: Serum melatonin from fertile women was higher than infertile women but the difference was not significant (p= 0.46. MDA level in fertile women was significantly lower than infertile women (p<0.001 and the level of TAC in fertile women was significantly higher than infertile women (p<0.001. Spearman test revealed a significant and direct correlation between melatonin and TAC in fertile and infertile women and a significant but reverse correlation between melatonin and MDA in infertile and fertile women. Conclusion: Differences in the level of oxidative stress biomarkers in fertile and infertile individuals have been reported. This study revealed a significant correlation between melatonin and oxidative stress biomarkers, concluding that melatonin level could be involved in infertility.

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.

Metformin induces oxidative stress in white adipocytes and raises uncoupling protein 2 levels.

Science.gov (United States)

Anedda, Andrea; Rial, Eduardo; González-Barroso, M Mar

2008-10-01

Metformin is a drug widely used to treat type 2 diabetes. It enhances insulin sensitivity by improving glucose utilization in tissues like liver or muscle. Metformin inhibits respiration, and the decrease in cellular energy activates the AMP-activated protein kinase that in turn switches on catabolic pathways. Moreover, metformin increases lipolysis and beta-oxidation in white adipose tissue, thereby reducing the triglyceride stores. The uncoupling proteins (UCPs) are transporters that lower the efficiency of mitochondrial oxidative phosphorylation. UCP2 is thought to protect against oxidative stress although, alternatively, it could play an energy dissipation role. The aim of this work was to analyse the involvement of UCP2 on the effects of metformin in white adipocytes. We studied the effect of this drug in differentiating 3T3-L1 adipocytes and found that metformin causes oxidative stress since it increases the levels of reactive oxygen species (ROS) and lowers the aconitase activity. Variations in UCP2 protein levels parallel those of ROS. Metformin also increases lipolysis in these cells although only when the levels of ROS and UCP2 have decreased. Hence, UCP2 does not appear to be needed to facilitate fatty acid oxidation. Furthermore, treatment of C57BL/6 mice with metformin also augmented the levels of UCP2 in epididymal white adipose tissue. We conclude that metformin treatment leads to the overexpression of UCP2 in adipocytes to minimize the oxidative stress that is probably due to the inhibition of respiration caused by the drug.

Patterns and determinants of stress among consultant physicians working in Saudi Arabia.

Science.gov (United States)

Alosaimi, Fahad D; Alawad, Hossam S; Alamri, Ayedh K; Saeed, Abdullah I; Aljuaydi, Khalid A; Alotaibi, Alwaleed S; Alotaibi, Khalid M; Alfaris, Eiad A

2018-01-01

Physicians experience several work-related stressors that have been mounting up in recent decades. This study aimed to examine perceived stress and its risk factors and consequences among consultant physicians in Saudi Arabia. A cross-sectional study was conducted from November 2014 to March 2015 among physicians who were assigned rank of consultant. The stress level was assessed using perceived stress scale (PSS). A total of 582 consultants participated. The average age was 46.9±7.9 years, 71% were males, 56% were Saudi, 15% were smokers, and 68% slept ≤6 hours per night. The median PSS score was 17 (interquartile range of 14-21), which represented 44% of maximum possible PSS score. The upper tertile of PSS score (represents a high stress level) was significantly associated with being younger, female, and Saudi. The majority (85%) considered job environment to be stressful and ~50% attributed that to a high workload and a noncooperative administration. In the year preceding this study, half of consultants frequently contemplated or even worked toward changing their medical institutes or even moving to work outside Saudi Arabia because of perception of a stressful working environment. Over the previous year, encountering life stressors, considering job environment as stressful and experiencing passive suicidal ideation, were significantly associated with higher levels of stress. In multivariate analysis, the following factors were independently associated with stress: female gender (odds ratio [OR]=2.41, 95% CI 1.58-3.70) and perceived stressful working environment (OR=3.66, 95% CI 1.87-7.17). Consultant physicians in Saudi Arabia experience moderate to high levels of perceived stress that are relatively comparable to physicians worldwide. A significant association was found between stress levels and both female gender and perception of a stressful working environment. Further studies are required to assess physician-based interventions and organization

The effect of organisational restructuring on job satisfaction, career aspirations and stress levels of employees

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E. N. Marais

1996-06-01

Full Text Available The field study reported here examined the effects of organisational restructuring on employees' job satisfaction, career aspirations and stress levels. Immediately after restructuring took place in the organisation, the employees affected by this advent were tested to determine whether restructuring would impact on the three variables. Eight months after restructuring in the organisation took place their job satisfaction, career aspirations and stress levels were measured again. The results of the research indicated no changes in job satisfaction levels, career aspirations or stress levels. The results provided no support for the expectation that after a time lapse of eight months the effects or organisational restructuring would diminish and that workers would experience a greater degree of job satisfaction. In addition, it would appear that the time lapse did not improve perceived career prospects or that stress levels decreased. Opsomming Die navorsing wat hier gerapporteer word/ het die effek van organisatoriese herstrukturering op werknemers se werkstevredenheid, loopbaanaspirasies en spanningsvlakke ondersoek. Onmiddellik nadat herstrukturering in die organisasie plaasgcvind het, is die werknemers wat deur die herstrukturering geraak is, getoets om vas te stel of herstrukturering 'n impak op die drie veranderlikes sou hê. Agt maande later is hul werkstevredenheid, loopbaanaspirasies en spanningsvlakke weer gemeet. Daar is gevind dat die werknemers se reaksie op organisatoriese herstrukturering onveranderd gebly het. Die resultate het geen steun verleen aan die verwagting dat die tydsverloop van agt maande die effek van organisatoriese herstrukturering sal verminder nie en dat werknemers tot 'n groter mate werkstevredenheid sal ervaar nie. Dit blyk verder dat die tydsverloop ook nie verbeterde loopbaanvooruitsigte tot gevolg gehad het of dat die werknemers se spanningsvlakke verlaag het nie.

The relationship between the level of aggression and the sleep quality in patients with posttraumatic stress disorder

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Taner Oznur

2015-12-01

Full Text Available Subject: Sleep disorders are common problems in post-traumatic stress disorder (PTSD patients. The main symptoms associated with sleep disorders were reported as a reduction in total sleep time, prolonged sleep latency, increase in the number wakefulness, low sleep efficiency and a reduction in the percentage of deep sleep stages. A relation between sleep disorders and increased levels of aggression was determined. In this study, we aimed to examine the relationship between the quality of sleep and the level of aggression in patients with Post Traumatic Stress Disorder. Method: The study was included 48 patients with a diagnosis of PTSD who were hospitalized. Data were collected using post-traumatic stress disorder questionnaire scale, Pittsburgh sleep quality scale and the Buss-Perry Aggression Scale applied by the clinician. Data analysis was made using SPSS 15.0 package program. Descriptive statistics and Pearson's correlation test were used in statistical analysis. Results: The average age of the cases was 32.33 +/- 7.93, the average of the symptoms of post-traumatic stress disorder was 56.23 +/- 11.14, the average of sleep quality was 22.08 +/- 6.67 and the average of aggression levels was 51.67 +/- 7.48. There was a high level deterioration in sleep quality and aggression levels were medium/medium-high levels. It was determined that Buss-Perry Aggression Scale scores were positively correlated with Pittsburgh sleep quality and posttraumatic stress disorder total and hyper arousal subscale scores. Conclusion: In this study, it is stated that increase in overstimulation symptoms and degradation of sleep in PTSD patients cause increase in agression levels. Degradation of sleep is determined as an indicator of agression that is observed in TSSB patients. Associatively, in PTSD patients, use of interventions to improve the quality of sleep oriented agressive behaviours gain value [TAF Prev Med Bull 2015; 14(6.000: 433-437

Radiation and Heat Stress Impact on Plasma Levels of Thyroid Hormones, Lipid Fractions, Glucose and Liver Glycogen in rats

International Nuclear Information System (INIS)

Abdel-Fattah, K.I.; Abou-Safi, H.M.

2003-01-01

Since Egypt is classified as a hot country, the present work has been directed to study the combined effect of heat stress and gamma radiation exposure on blood thyroid hormonal levels and some other parameters. Four groups of rats were served as: control, whole-body gamma irradiated (6Gy), exposed to ambient heat stress (38 C-40 C) and a group exposed to heat stress and irradiation. Four time intervals 1, 3, 5 and 7 days were determined for heat stress or exposure to heat followed by irradiation. Blood samples and liver specimens were taken at the end of each time interval in the third group and after one hour of irradiation in the second and fourth groups. To detect the radiation effects after the different periods of heat stress, plasma levels of thyroid hormones (T3 and T4), lipid fractions (triglycerides, total cholesterol, HDL- and LDL-cholesterol), glucose and liver glycogen content were determined. The results revealed that exposure to heat and ionizing radiation leads to a decrease in the levels of thyroid hormones, which was mostly pronounced in the T3 levels. Plasma glucose levels showed significant elevations in both, the heat-stressed group and the heat-treated then irradiated group. While, liver glycogen content exhibited similar elevations only during the 1st, 3 rd and 5 th days of heating followed by irradiation treatment as compared to the heat stressed group. Yet, it showed significant declines in comparison with both control and irradiated groups. Enormous increments in all determined plasma lipid fractions were induced by heat stress and / or gamma radiation

Study of Level of Stress in the Parents of Children with Attention-Deficit/Hyperactivity Disorder

Science.gov (United States)

Sethi, Sujata; Gandhi, Raghu; Anand, Vidhu

2012-01-01

Background: Parents who have children with attention-deficit hyperactivity disorder (ADHD) often experience high level of stress related to caring for their children. But not much research has been conducted in this area in India. This study aimed to assess the stress of parenting children with ADHD. Methods: This is a clinic based comparative…

Acute effects of low-level laser therapy (660 nm) on oxidative stress levels in diabetic rats with skin wounds.

Science.gov (United States)

Denadai, Amanda Silveira; Aydos, Ricardo Dutra; Silva, Iandara Schettert; Olmedo, Larissa; de Senna Cardoso, Bruno Mendonça; da Silva, Baldomero Antonio Kato; de Carvalho, Paulo de Tarso Camillo

2017-09-01

Laser therapy influences oxidative stress parameters such as the activity of antioxidant enzymes and the production of reactive oxygen species. To analyze the effects of low-level laser therapy on oxidative stress in diabetics rats with skin wounds. Thirty-six animals were divided into 4 groups: NDNI: non-diabetic rats with cutaneous wounds that not received laser therapy; NDI: non-diabetic rats with cutaneous wounds that received laser therapy; DNI: diabetic rats with skin wounds who did not undergo laser therapy; DI: rats with diabetes insipidus and cutaneous wounds and received laser therapy. The animals were treated with LLLT (660 nm, 100 mW, 6 J/cm, spot size 0.028 cm). On the day of killing the animals, tissue-wrapped cutaneous wounds were collected and immediately frozen, centrifuged, and stored to analyze malondialdehyde (MDA) levels. Significant difference was observed within the groups of MDA levels (ANOVA, p = 0.0001). Tukey's post-hoc test showed significantly lower values of MDA in irradiated tissues, both in diabetic and non-diabetic rats. ANOVA of the diabetic group revealed a significant difference (p < 0.01) when all groups, except NDI and DI, were compared. LLLT was effective in decreasing MDA levels in acute surgical wounds in diabetic rats.

Suitability of the charm HVS and a microbiological multiplate system for detection of residues in raw milk at EU maximum residue levels

NARCIS (Netherlands)

Nouws, J.F.M.; Egmond, van H.; Loeffen, G.; Schouten, J.; Keukens, H.; Smulders, I.; Stegeman, H.

1999-01-01

In this paper we assessed the suitability of the Charm HVS and a newly developed microbiological multiplate system as post-screening tests to confirm the presence of residues in raw milk at or near the maximum permissible residue level (MRL). The multiplate system is composed of Bacillus

The San Diego East County school shootings: a qualitative study of community-level post-traumatic stress.

Science.gov (United States)

Palinkas, Lawrence A; Prussing, Erica; Reznik, Vivian M; Landsverk, John A

2004-01-01

Within one month (March 2001), two separate incidents of school shootings occurred at two different high schools within the same school district in San Diego's East County. To examine community-wide expressions of post-traumatic distress resulting from the shootings that may or may not fulfill DSM-IV criteria for post-traumatic stress disorder (PTSD), but which might interfere with treatment and the prevention of youth violence. A qualitative study was undertaken using Rapid Assessment Procedures (RAP) in four East San Diego County communities over a six-month period following the two events. Semi-structured interviews were conducted with 85 community residents identified through a maximum variation sampling technique. Interview transcripts were analyzed by coding consensus, co-occurrence, and comparison, using text analysis software. Three community-wide patterns of response to the two events were identified: (1) 52.9% of respondents reported intrusive reminders of the trauma associated with intense media coverage and subsequent rumors, hoaxes, and threats of additional acts of school violence; (2) 44.7% reported efforts to avoid thoughts, feelings, conversations, or places (i.e., schools) associated with the events; negative assessment of media coverage; and belief that such events in general cannot be prevented; and (3) 30.6% reported anger, hyper-vigilance, and other forms of increased arousal. Twenty-three (27.1%) respondents reported symptoms of fear, anxiety, depression, drug use, and psychosomatic symptoms in themselves or others. School shootings can precipitate symptoms of post-traumatic stress disorder at the community level. Such symptoms hinder the treatment of individuals with PTSD and the implementation of effective prevention strategies and programs.

The Influence of Stress Factors on the Effectiveness of Passing the Assessment by Employees with Different Levels of Creativity

Directory of Open Access Journals (Sweden)

Khachaturova M.R.

2018-03-01

Full Text Available The skills of non-standard thinking and creativity play an important role in stressful situations. We hypothesized that stress factors influence the effectiveness of passing the assessment by employees: high level of creativity increases the effectiveness of task execution. We conducted the experiment and used J. Guilford’s technique and tasks on creativity thinking, created by T. Lubart and G. Altshuller. The sample consisted of 200 examinees (92 females and 108 males, employees of different organizations (age — from 23 to 60. The results show that time limitation as a stressful factor decreases the effectiveness of passing the assessment by employees with both low and high levels of creativity (p≤0,01. Work in a pair does not influence the effectiveness of passing the assessment regardless of the level of creativity (p≥0,05. Multitasking is stressful for employees with a low level of creativity (p≤0,01. The results of our research can be taken as principles of psychological trainings for development of employees’ stress-resistance.

Effect of stress level on static young's modulus of certain structural materials

International Nuclear Information System (INIS)

Vojtenko, A.F.; Skripnik, Yu.D.; Solov'eva, N.G.; Nadezhdin, G.N.

1982-01-01

Certain steels, titanium and aluminium alloys have been studied for their dynamic and static Young moduli. It is shown that a stress rise in materials to the level of microplastic strain realization results in a significant reduction of the static modulus of elasticity in the materials studied

A study of job stress, stress coping strategies, and job satisfaction for nurses working in middle-level hospital operating rooms.

Science.gov (United States)

Chen, Chung-Kuang; Lin, Cecilia; Wang, Shu-Hui; Hou, Tung-Hsu

2009-09-01

Understanding the interactive relationships between demographics and work-related variables, job stress, job stress coping strategies, and job satisfaction for operating room (OR) nurses is important. The purpose of this study was to determine the stressors, the stress coping strategies, and the job satisfaction of nursing staff who worked in the OR and to evaluate influence of demographic characteristics on job stress, stress coping strategies, and job satisfaction. A cross-sectional research design was used to collect data. Participants included 121 nurses with more than 6 months of work experience at seven hospitals in Yunlin and Chiayi Counties. Data were collected from March through May 2008. One hundred twelve questionnaires were returned, giving a response rate of 92.56%. The questionnaire included four parts designed to gather data on demographics and work-related information, job stress, stress coping strategies, and job satisfaction. Major findings of this study were as follows: (a) stress level and frequency perception of OR nurses were significantly related to the type of hospital; (b) the most intense stressor perceived by OR nurses was patient safety; (c) the stressor most frequently perceived by OR nurses was administrative feedback; (d) although all job stressors were positively related to destructive stress coping strategies, professional status, patient safety, and OR environment were also positively related to constructive stress coping strategies; (e) factors including work rewards, OR environment, and administrative management of job satisfaction were inversely related to destructive stress coping strategies; and (f) factors including work rewards, OR environment, and administrative management of job satisfaction were inversely related to all job stressors. Major suggestions of this study include the following: (a) hospitals should ensure set standard operating procedures for the OR, strengthen the designed-in security of the OR working

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.

The relation between fearfulness in young and stress-response in adult laying hens, on individual and group level

NARCIS (Netherlands)

de Haas, Elske N.; Kops, Marjolein S.; Bolhuis, J. Elizabeth; Groothuis, Ton G. G.; Ellen, Esther D.; Rodenburg, T. Bas

2012-01-01

Fearfulness of an individual can affect its sensitivity to stress, while at the same time the social situation in which an animal lives can affect its fear level. It is however unknown what the long-term effects of high fearfulness on sensitivity to stress are, on individual or group level in laying

A comparative study on stress and compliance based structural topology optimization

Science.gov (United States)

Hailu Shimels, G.; Dereje Engida, W.; Fakhruldin Mohd, H.

2017-10-01

Most of structural topology optimization problems have been formulated and solved to either minimize compliance or weight of a structure under volume or stress constraints, respectively. Even if, a lot of researches are conducted on these two formulation techniques separately, there is no clear comparative study between the two approaches. This paper intends to compare these formulation techniques, so that an end user or designer can choose the best one based on the problems they have. Benchmark problems under the same boundary and loading conditions are defined, solved and results are compared based on these formulations. Simulation results shows that the two formulation techniques are dependent on the type of loading and boundary conditions defined. Maximum stress induced in the design domain is higher when the design domains are formulated using compliance based formulations. Optimal layouts from compliance minimization formulation has complex layout than stress based ones which may lead the manufacturing of the optimal layouts to be challenging. Optimal layouts from compliance based formulations are dependent on the material to be distributed. On the other hand, optimal layouts from stress based formulation are dependent on the type of material used to define the design domain. High computational time for stress based topology optimization is still a challenge because of the definition of stress constraints at element level. Results also shows that adjustment of convergence criterions can be an alternative solution to minimize the maximum stress developed in optimal layouts. Therefore, a designer or end user should choose a method of formulation based on the design domain defined and boundary conditions considered.

Detection of Stress Levels from Biosignals Measured in Virtual Reality Environments Using a Kernel-Based Extreme Learning Machine.

Science.gov (United States)

Cho, Dongrae; Ham, Jinsil; Oh, Jooyoung; Park, Jeanho; Kim, Sayup; Lee, Nak-Kyu; Lee, Boreom

2017-10-24

Virtual reality (VR) is a computer technique that creates an artificial environment composed of realistic images, sounds, and other sensations. Many researchers have used VR devices to generate various stimuli, and have utilized them to perform experiments or to provide treatment. In this study, the participants performed mental tasks using a VR device while physiological signals were measured: a photoplethysmogram (PPG), electrodermal activity (EDA), and skin temperature (SKT). In general, stress is an important factor that can influence the autonomic nervous system (ANS). Heart-rate variability (HRV) is known to be related to ANS activity, so we used an HRV derived from the PPG peak interval. In addition, the peak characteristics of the skin conductance (SC) from EDA and SKT variation can also reflect ANS activity; we utilized them as well. Then, we applied a kernel-based extreme-learning machine (K-ELM) to correctly classify the stress levels induced by the VR task to reflect five different levels of stress situations: baseline, mild stress, moderate stress, severe stress, and recovery. Twelve healthy subjects voluntarily participated in the study. Three physiological signals were measured in stress environment generated by VR device. As a result, the average classification accuracy was over 95% using K-ELM and the integrated feature (IT = HRV + SC + SKT). In addition, the proposed algorithm can embed a microcontroller chip since K-ELM algorithm have very short computation time. Therefore, a compact wearable device classifying stress levels using physiological signals can be developed.

Quantile-based Bayesian maximum entropy approach for spatiotemporal modeling of ambient air quality levels.

Science.gov (United States)

Yu, Hwa-Lung; Wang, Chih-Hsin

2013-02-05

Understanding the daily changes in ambient air quality concentrations is important to the assessing human exposure and environmental health. However, the fine temporal scales (e.g., hourly) involved in this assessment often lead to high variability in air quality concentrations. This is because of the complex short-term physical and chemical mechanisms among the pollutants. Consequently, high heterogeneity is usually present in not only the averaged pollution levels, but also the intraday variance levels of the daily observations of ambient concentration across space and time. This characteristic decreases the estimation performance of common techniques. This study proposes a novel quantile-based Bayesian maximum entropy (QBME) method to account for the nonstationary and nonhomogeneous characteristics of ambient air pollution dynamics. The QBME method characterizes the spatiotemporal dependence among the ambient air quality levels based on their location-specific quantiles and accounts for spatiotemporal variations using a local weighted smoothing technique. The epistemic framework of the QBME method can allow researchers to further consider the uncertainty of space-time observations. This study presents the spatiotemporal modeling of daily CO and PM10 concentrations across Taiwan from 1998 to 2009 using the QBME method. Results show that the QBME method can effectively improve estimation accuracy in terms of lower mean absolute errors and standard deviations over space and time, especially for pollutants with strong nonhomogeneous variances across space. In addition, the epistemic framework can allow researchers to assimilate the site-specific secondary information where the observations are absent because of the common preferential sampling issues of environmental data. The proposed QBME method provides a practical and powerful framework for the spatiotemporal modeling of ambient pollutants.

Relationship among Periodontal Disease, Insulin Resistance, Salivary Cortisol, and Stress Levels during Pregnancy.

Science.gov (United States)

Seraphim, Ana Paula Castilho Garcia; Chiba, Fernando Yamamoto; Pereira, Renato Felipe; Mattera, Maria Sara de Lima Coutinho; Moimaz, Suzely Adas Saliba; Sumida, Doris Hissako

2016-01-01

Pregnancy is a period involving important metabolic changes that enable the maintenance of the mother's health and development of the fetus. This study aimed to assess the relationship among periodontal disease, insulin resistance, salivary cortisol concentration and level of perceived stress in pregnant women. This was a cross-sectional study. The sample comprised 96 pregnant women between the fifth and seventh month of pregnancy registered at the Basic Health Units of the Unified Health System (SUS). The periodontal condition was assessed after obtainment free and informed consent from the participants. Participants were divided into three groups: control subjects with a healthy periodontal condition (CN; n=46), patients with gingivitis (GI; n=26), and patients with periodontitis (PI; n=24). Saliva and blood samples were collected for evaluation of salivary cortisol concentration, glycemia, insulinemia and Homeostasis Model Assessment-Insulin Resistance index. A validated survey for the assessment of perceived stress levels was also performed. PI group showed significantly higher (pperiodontal disease during pregnancy. This study emphasizes the importance of preventing periodontitis in order to avoid insulin resistance and stress during pregnancy since these can cause systemic complications for the mother and the fetus.

Acclimation increases freezing stress response of Arabidopsis thaliana at proteome level

KAUST Repository

Fanucchi, Francesca

2012-06-01

This study used 2DE to investigate how Arabidopsis thaliana modulates protein levels in response to freezing stress after sub-lethal exposure at - 10 °C, both in cold-acclimated and in non-acclimated plants. A map was implemented in which 62 spots, corresponding to 44 proteins, were identified. Twenty-two spots were modulated upon treatments, and the corresponding proteins proved to be related to photosynthesis, energy metabolism, and stress response. Proteins demonstrated differences between control and acclimation conditions. Most of the acclimation-responsive proteins were either not further modulated or they were down-modulated by freezing treatment, indicating that the levels reached during acclimation were sufficient to deal with freezing. Anabolic metabolism appeared to be down-regulated in favor of catabolic metabolism. Acclimated plants and plants submitted to freezing after acclimation showed greater reciprocal similarity in protein profiles than either showed when compared both to control plants and to plants frozen without acclimation. The response of non-acclimated plants was aimed at re-modulating photosynthetic apparatus activity, and at increasing the levels of proteins with antioxidant-, molecular chaperone-, or post-transcriptional regulative functions. These changes, even less effective than the acclimation strategy, might allow the injured plastids to minimize the production of non-useful metabolites and might counteract photosynthetic apparatus injuries. © 2012 Elsevier B.V. All rights reserved.

Acclimation increases freezing stress response of Arabidopsis thaliana at proteome level

KAUST Repository

Fanucchi, Francesca; Alpi, Emanuele; Olivieri, Stefano; Cannistraci, Carlo; Bachi, Angela; Alpi, Amedeo; Alessio, Massimo

2012-01-01

This study used 2DE to investigate how Arabidopsis thaliana modulates protein levels in response to freezing stress after sub-lethal exposure at - 10 °C, both in cold-acclimated and in non-acclimated plants. A map was implemented in which 62 spots, corresponding to 44 proteins, were identified. Twenty-two spots were modulated upon treatments, and the corresponding proteins proved to be related to photosynthesis, energy metabolism, and stress response. Proteins demonstrated differences between control and acclimation conditions. Most of the acclimation-responsive proteins were either not further modulated or they were down-modulated by freezing treatment, indicating that the levels reached during acclimation were sufficient to deal with freezing. Anabolic metabolism appeared to be down-regulated in favor of catabolic metabolism. Acclimated plants and plants submitted to freezing after acclimation showed greater reciprocal similarity in protein profiles than either showed when compared both to control plants and to plants frozen without acclimation. The response of non-acclimated plants was aimed at re-modulating photosynthetic apparatus activity, and at increasing the levels of proteins with antioxidant-, molecular chaperone-, or post-transcriptional regulative functions. These changes, even less effective than the acclimation strategy, might allow the injured plastids to minimize the production of non-useful metabolites and might counteract photosynthetic apparatus injuries. © 2012 Elsevier B.V. All rights reserved.

Stress analysis in a pedicle screw fixation system with flexible rods in the lumbar spine.

Science.gov (United States)

Kim, Kyungsoo; Park, Won Man; Kim, Yoon Hyuk; Lee, SuKyoung

2010-01-01

Breakage of screws has been one of the most common complications in spinal fixation systems. However, no studies have examined the breakage risk of pedicle screw fixation systems that use flexible rods, even though flexible rods are currently being used for dynamic stabilization. In this study, the risk of breakage of screws for the rods with various flexibilities in pedicle screw fixation systems is investigated by calculating the von Mises stress as a breakage risk factor using finite element analysis. Three-dimensional finite element models of the lumbar spine with posterior one-level spinal fixations at L4-L5 using four types of rod (a straight rod, a 4 mm spring rod, a 3 mm spring rod, and a 2 mm spring rod) were developed. The von Mises stresses in both the pedicle screws and the rods were analysed under flexion, extension, lateral bending, and torsion moments of 10 Nm with a follower load of 400 N. The maximum von Mises stress, which was concentrated on the neck region of the pedicle screw, decreased as the flexibility of the rod increased. However, the ratio of the maximum stress in the rod to the yield stress increased substantially when a highly flexible rod was used. Thus, the level of rod flexibility should be considered carefully when using flexible rods for dynamic stabilization because the intersegmental motion facilitated by the flexible rod results in rod breakage.

Chronic Stress Induces Structural Alterations in Splenic Lymphoid Tissue That Are Associated with Changes in Corticosterone Levels in Wistar-Kyoto Rats

Directory of Open Access Journals (Sweden)

María Eugenia Hernandez

2013-01-01

Full Text Available Major depressive disorder patients present chronic stress and decreased immunity. The Wistar-Kyoto rat (WKY is a strain in which the hypothalamic-pituitary-adrenal axis is overactivated. To determine whether chronic stress induces changes in corticosterone levels and splenic lymphoid tissue, 9-week-old male rats were subject to restraint stress (3 h daily, chemical stress (hydrocortisone treatment, 50 mg/Kg weight, mixed stress (restraint plus hydrocortisone, or control treatment (without stress for 1, 4, and 7 weeks. The serum corticosterone levels by RIA and spleens morphology were analyzed. Corticosterone levels as did the structure, size of the follicles and morphology of the parenchyma (increase in red pulp in the spleen, varied depending on time and type of stressor. These changes indicate that chronic stress alters the immune response in the spleen in WKY rats by inducing morphological changes, explaining in part the impaired immunity that develops in organisms that are exposed to chronic stress.

Differences in response to heat stress due to production level and breed of dairy cows

Science.gov (United States)

Gantner, Vesna; Bobic, Tina; Gantner, Ranko; Gregic, Maja; Kuterovac, Kresimir; Novakovic, Jurica; Potocnik, Klemen

2017-09-01

The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance?

Mercury levels assessment and its relationship with oxidative stress biomarkers in children from three localities in Yucatan, Mexico.

Science.gov (United States)

Rangel-Méndez, Jorge A; Arcega-Cabrera, Flor E; Fargher, Lane F; Moo-Puc, Rosa E

2016-02-01

Mercury (Hg) is a global pollutant that is released into the environment from geologic and anthropogenic sources. Once it enters an organism, it generates several toxicity mechanisms and oxidative stress has been proposed as the main one. Metal susceptibility is greater in children, which is a result of their physiology and behavior. In Yucatan, Mexico, burning of unregulated garbage dumps and household trash, ingestion of top marine predators, and pottery manufacturing are among the conditions that could promote Hg exposure. However, for Yucatan, there are no published studies that report Hg levels and associated oxidative stress status in children. Therefore, this study aimed to assess Hg levels in blood and urine and oxidative stress biomarkers levels in a sample of 107 healthy children from three localities in Yucatan, Mexico, as well as investigate the relationship between these parameters. Hg was detected in 11 (10.28%) of blood samples and 38 (35.51%) of urine samples collected from the participating children. Fourteen subjects showed Hg above recommended levels. The oxidative stress biomarkers were slightly elevated in comparison with other studies and were statistically different between the sampling sites. No linear correlation between Hg levels and oxidative stress biomarkers was found. Nevertheless, exploratory univariate and multivariate analysis showed non-linear relations among the measured variables. Globally, the study provides, for the first time, information regarding Hg levels and their relationship with oxidative stress biomarkers in a juvenile population from Mexico's southeast (Yucatan) region. In agreement with worldwide concern about Hg, this study should stimulate studies on metal monitoring in humans (especially children) among scientists working in Mexico, the establishment of polices for its regulation, and the reduction of human health risks. Copyright © 2015 Elsevier B.V. All rights reserved.

Socioeconomic status in children is associated with hair cortisol levels as a biological measure of chronic stress.

Science.gov (United States)

Vliegenthart, J; Noppe, G; van Rossum, E F C; Koper, J W; Raat, H; van den Akker, E L T

2016-03-01

Low socioeconomic status (SES) may be associated with a high risk of lifestyle-related diseases such as cardiovascular diseases. There is a strong association between parental SES, stress and indicators of child health and adult health outcome. The exact mechanisms underlying this association have not yet been fully clarified. Low SES may be associated with chronic stress, which may lead to activation of the hypothalamic-pituitary-adrenal (HPA)-axis, resulting in a higher circulating level of the stress hormone cortisol. Therefore, chronic stress may mediate the association between low SES and elevated cortisol levels and its adverse outcomes. We investigated whether SES was associated with a chronic measure of cortisol exposure in a child population. Cortisol and cortisone were measured in scalp hair in 270 children and adolescents, aged 4-18 years, enrolled through school visits. Neighborhood level SES was based on a score developed by the Netherlands Institute for Social Research using postal codes, and this includes neighborhood measures of income education and unemployment. Maternal and paternal education level were used as indicators of family SES. Neighborhood level socioeconomic status score was significantly associated with hair cortisol (β=-0.103, p=0.007, 95%CI [-0.179, -0.028]) and hair cortisone (β=-0.091, p=0.023, 95%CI [-0.167, -0.015]), adjusted for age and sex. Additionally, hair cortisol was significantly correlated with maternal education level and hair cortisone was significantly correlated with paternal education level. The results of our study suggest that the widely shown association between low family SES and adverse child health outcomes may be mediated by chronic stress, given the chronically higher levels of cortisol in children and adolescents in families with low SES. It is especially notable that the association between SES and cortisol was already found in children of young age as this can have major consequences, such as increased

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.

Redesigning and Manufacturing of a Land Levelling Shovel by Assembly Structural Stress Analysis

OpenAIRE

Tahir Altinbalik; Gürkan İrsel

2014-01-01

The aim was to redesign and manufacture of a shovel for a pull-type land levelling machine, which, in its present condition, is used to get easily damaged even under low loads. Firstly, the maximum pulling load affecting the levelling shovel was experimentally determined. Then, stable-shovel system with the bolt connection was replaced with a bearing-shaft connection system. In this way, the new shovel has gained a capability of making oscillation motion so that it can operate on sloped groun...

Studies on laws of stress-magnetization based on magnetic memory testing technique

Science.gov (United States)

Ren, Shangkun; Ren, Xianzhi

2018-03-01

Metal magnetic memory (MMM) testing technique is a novel testing method which can early test stress concentration status of ferromagnetic components. Under the different maximum tensile stress, the relationship between the leakage magnetic field of at certain point of cold rolled steel specimen and the tensile stress was measured during the process of loading and unloading by repeated. It shows that when the maximum tensile stress is less than 610 MPa, the relationship between the magnetic induction intensity and the stress is linear; When the maximum tensile stress increase from 610 MPa to 653 MPa of yield point, the relationship between the magnetic induction intensity and the tensile becomes bending line. The location of the extreme point of the bending line will move rapidly from the position of smaller stress to the larger stress position, and the variation of magnetic induction intensity increases rapidly. When the maximum tensile stress is greater than the 653 MPa of yield point, the variation of the magnetic induction intensity remains large, and the position of the extreme point moves very little. In theoretical aspects, tensile stress is to be divided into ordered stress and disordered stress. In the stage of elastic stress, a microscopic model of the order stress magnetization is established, and the conclusions are in good agreement with the experimental data. In the plastic deformation stage, a microscopic model of disordered stress magnetization is established, and the conclusions are in good agreement with the experimental data, too. The research results can provide reference for the accurate quantitative detection and evaluation of metal magnetic memory testing technology.

Neurosignal record with a Brain-Computer interface to estimate the level of stress in a student during a class

Directory of Open Access Journals (Sweden)

Luz Angela Moreno Cueva

2017-07-01

Full Text Available Introduction: This work shows an individual study of the capture, recording, and analysis of the level of stress of a university student during a class that involves an evaluation. The stress information was estimated using a commercial and low-cost computer-brain interface. This allows solving the problem of easily obtaining quantitative and not only qualitative measures. Objective: The aim of this article is to analyze the behavior of neural signals to estimate the level of stress in a student to some verbal and nonverbal events generated by a teacher. Methodology: An experimental design of individual character was developed taking as disturbances the level of stress, events such as questions, time limits, and gestures. Results: Some events that caused stress in students produced by the verbal and non-verbal language of the teacher when teaching the class were evidenced. Conclusions: Teachers are encouraged to moderate their body language during assessments by avoiding actions that emulate anxieties or pressures in unnecessary times.

Nitrogen Metabolism in Adaptation of Photosynthesis to Water Stress in Rice Grown under Different Nitrogen Levels

Directory of Open Access Journals (Sweden)

Chu Zhong

2017-06-01

Full Text Available To investigate the role of nitrogen (N metabolism in the adaptation of photosynthesis to water stress in rice, a hydroponic experiment supplying with low N (0.72 mM, moderate N (2.86 mM, and high N (7.15 mM followed by 150 g⋅L-1 PEG-6000 induced water stress was conducted in a rainout shelter. Water stress induced stomatal limitation to photosynthesis at low N, but no significant effect was observed at moderate and high N. Non-photochemical quenching was higher at moderate and high N. In contrast, relative excessive energy at PSII level (EXC was declined with increasing N level. Malondialdehyde and hydrogen peroxide (H2O2 contents were in parallel with EXC. Water stress decreased catalase and ascorbate peroxidase activities at low N, resulting in increased H2O2 content and severer membrane lipid peroxidation; whereas the activities of antioxidative enzymes were increased at high N. In accordance with photosynthetic rate and antioxidative enzymes, water stress decreased the activities of key enzymes involving in N metabolism such as glutamate synthase and glutamate dehydrogenase, and photorespiratory key enzyme glycolate oxidase at low N. Concurrently, water stress increased nitrate content significantly at low N, but decreased nitrate content at moderate and high N. Contrary to nitrate, water stress increased proline content at moderate and high N. Our results suggest that N metabolism appears to be associated with the tolerance of photosynthesis to water stress in rice via affecting CO2 diffusion, antioxidant capacity, and osmotic adjustment.

Reiki brief report: using Reiki to reduce stress levels in a nine-year-old child.

Science.gov (United States)

Bukowski, Elaine L; Berardi, Diana

2014-01-01

A nine-year-old female with a history of perinatal stroke, seizures, and type-I diabetes was seen for six weeks of Reiki to determine the effects of Reiki on relaxation, and in turn, the prevention of future seizures. The secondary and tertiary aims were to determine the effects of Reiki on sleep patterns and the stress levels of the mother. There was a decrease in stress in both the child and the mother, as measured by a modified Perceived Stress Scale and a Perceived Stress Scale, respectively. There was no change in the child's overall sense of well-being, as measured by a global questionnaire. There was a positive change in sleep patterns on 33.3% of the nights during which the study occurred, as reported on a sleep log kept by the mother. The child and the Reiki Master (a Reiki practitioner who has completed all three levels of Reiki certification training and trains and certifies individuals in the practice of Reiki as well as provides Reiki to individuals) experienced warmth and tingling sensations on the same area of the child during the Reiki sessions. The child relaxed within the first five to seven minutes of each session as reported by the Reiki Master. There were no reports of seizures during this study. Reiki may be a useful adjunct for children with increased stress levels and sleep disturbances secondary to their medical condition. Further research is warranted to evaluate the use of Reiki in children, particularly with a large sample size, and to evaluate the long-term use of Reiki and its effects on adequate sleep. Copyright © 2014 Elsevier Inc. All rights reserved.

Selective and context-dependent effects of chemical stress across trophic levels at the basis of marine food webs.

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Mensens, Christoph; De Laender, Frederik; Janssen, Colin R; Rivera, Frances Camille; Sabbe, Koen; De Troch, Marleen

2018-04-26

Human activities increasingly impact the functioning of marine food webs, but anthropogenic stressors are seldom included in ecological study designs. Diet quality, as distinct from just diet quantity, has moreover rarely been highlighted in food web studies in a stress context. We measured the effects of metal and pesticide stress (copper and atrazine) on the contribution of a benthic intertidal diatom community to two processes that are key to the functioning of intertidal systems: biomass (diet quantity) and lipid (diet quality) production. We then examined if stressors affected diatom functioning by selectively targeting the species contributing most to functioning (selective stress effects) or by changing the species' functional contribution (context-dependent effects). Finally, we tested if stress-induced changes in diet quality altered the energy flow to the diatoms' main grazers (harpacticoid copepods). Diatom diet quantity was reduced by metal stress but not by low pesticide levels due to the presence of an atrazine-tolerant, mixotrophic species. Selective effects of the pesticide reduced diatom diet quality by 60% and 75% at low and high pesticide levels respectively, by shifting diatom community structure from dominance by lipid-rich species toward dominance by an atrazine-tolerant, but lipid-poor, species. Context-dependent effects did not affect individual diatom lipid content at low levels of both stressors, but caused diatoms to lose 40% of their lipids at high copper stress. Stress-induced changes in diet quality predicted the energy flow from the diatoms to their copepod consumers, which lost half of their lipids when feeding on diatoms grown under low and high pesticide and high metal stress. Selective pesticide effects were a more important threat for trophic energy transfer than context-dependent effects of both stressors, with shifts in diatom community structure affecting the energy flow to their copepod grazers at stress levels where no

Stress leads to contrasting effects on the levels of brain derived neurotrophic factor in the hippocampus and amygdala.

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Harini Lakshminarasimhan

Full Text Available Recent findings on stress induced structural plasticity in rodents have identified important differences between the hippocampus and amygdala. The same chronic immobilization stress (CIS, 2 h/day causes growth of dendrites and spines in the basolateral amygdala (BLA, but dendritic atrophy in hippocampal area CA3. CIS induced morphological changes also differ in their temporal longevity--BLA hypertrophy, unlike CA3 atrophy, persists even after 21 days of stress-free recovery. Furthermore, a single session of acute immobilization stress (AIS, 2 h leads to a significant increase in spine density 10 days, but not 1 day, later in the BLA. However, little is known about the molecular correlates of the differential effects of chronic and acute stress. Because BDNF is known to be a key regulator of dendritic architecture and spines, we investigated if the levels of BDNF expression reflect the divergent effects of stress on the hippocampus and amygdala. CIS reduces BDNF in area CA3, while it increases it in the BLA of male Wistar rats. CIS-induced increase in BDNF expression lasts for at least 21 days after the end of CIS in the BLA. But CIS-induced decrease in area CA3 BDNF levels, reverses to normal levels within the same period. Finally, BDNF is up regulated in the BLA 1 day after AIS and this increase persists even 10 days later. In contrast, AIS fails to elicit any significant change in area CA3 at either time points. Together, these findings demonstrate that both acute and chronic stress trigger opposite effects on BDNF levels in the BLA versus area CA3, and these divergent changes also follow distinct temporal profiles. These results point to a role for BDNF in stress-induced structural plasticity across both hippocampus and amygdala, two brain areas that have also been implicated in the cognitive and affective symptoms of stress-related psychiatric disorders.

Exploring stress levels, job satisfaction, and quality of life in a sample of police officers in Greece.

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Alexopoulos, Evangelos C; Palatsidi, Vassiliki; Tigani, Xanthi; Darviri, Christina

2014-12-01

The ongoing economic crisis in Greece has affected both stress and quality of life (QoL) at all socioeconomic levels, including professionals in the police force. The aim of this study was to examine perceived stress, job satisfaction, QoL, and their relationships in a sample of police officers in Greece. A cross-sectional study was conducted during the first trimester of 2011 in 23 police stations in the greater Athens area. A total of 201 police officers agreed to participate (response rate 44.6%). The General Health Questionnaire-28 (GHQ-28) was used to assess general health, and the World Health Organization Quality of Life-BREF Questionnaire and Perceived Stress Scale-14 (PSS-14) questionnaires were used to assess QoL and perceived stress, respectively. The PSS and GHQ subscales and total scores exhibited strong, positive, and significant correlations coefficients (r): 0.52 for somatic disturbances, 0.56 for stress and insomnia, 0.40 for social dysfunction, and 0.37 for depression, yielding an r equal to 0.57 for the total GHQ score. A higher level of perceived stress was related to a lower likelihood of being satisfied with their job; in this regard, male participants and higher ranked officers reported lower job satisfaction. The PSS and GHQ scores were inversely, consistently, and significantly related to almost all of the QoL aspects, explaining up to 34% of their variability. Parenthood had a positive effect on QoL related to physical health, and women reported lower QoL related to psychological health. Higher levels of stress are related to an increased risk of reporting suboptimal job satisfaction and QoL. The magnitude of these associations varied depending on age, gender, and rank, highlighting the need for stress-management training.

What controls the maximum magnitude of injection-induced earthquakes?

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Eaton, D. W. S.

2017-12-01

Three different approaches for estimation of maximum magnitude are considered here, along with their implications for managing risk. The first approach is based on a deterministic limit for seismic moment proposed by McGarr (1976), which was originally designed for application to mining-induced seismicity. This approach has since been reformulated for earthquakes induced by fluid injection (McGarr, 2014). In essence, this method assumes that the upper limit for seismic moment release is constrained by the pressure-induced stress change. A deterministic limit is given by the product of shear modulus and the net injected fluid volume. This method is based on the assumptions that the medium is fully saturated and in a state of incipient failure. An alternative geometrical approach was proposed by Shapiro et al. (2011), who postulated that the rupture area for an induced earthquake falls entirely within the stimulated volume. This assumption reduces the maximum-magnitude problem to one of estimating the largest potential slip surface area within a given stimulated volume. Finally, van der Elst et al. (2016) proposed that the maximum observed magnitude, statistically speaking, is the expected maximum value for a finite sample drawn from an unbounded Gutenberg-Richter distribution. These three models imply different approaches for risk management. The deterministic method proposed by McGarr (2014) implies that a ceiling on the maximum magnitude can be imposed by limiting the net injected volume, whereas the approach developed by Shapiro et al. (2011) implies that the time-dependent maximum magnitude is governed by the spatial size of the microseismic event cloud. Finally, the sample-size hypothesis of Van der Elst et al. (2016) implies that the best available estimate of the maximum magnitude is based upon observed seismicity rate. The latter two approaches suggest that real-time monitoring is essential for effective management of risk. A reliable estimate of maximum

Financial strain is associated with increased oxidative stress levels: the Women's Health and Aging Studies.