899 resultados para Impact stress
Resumo:
The use of geotextiles in coastal structures such as revetments and bund walls has become a common practice. The performance of these structures during their lifetime depends on the durability of geotextile used. During construction of these coastal structures, geotextiles are subjected to a drop load with high impact stress and that can damage the geotextile. In the current design practice, index tests are insufficient in predicting the performance of the geotextile. This puts the stability and performance of the coastal structures at risk. The current geotextile design guidelines are based on index tests and there is no standard procedure to account for the potential loss in the geotextile’s mechanical properties during installation (construction).This study aims to develop a standard procedure to estimate the properties of geotextile after its installation and using these properties for designing the performance of these structures. This paper describes the laboratory method of simulating large scale rock dumping on non-woven geotextiles and how to quantify the retained strength of damaged geotextiles. Results show that the reduction in retained strength of geotextile could extent up to 26% during installation.
Electroglottographic analysis of actresses and nonactresses' voices in different levels of intensity
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Background: Previous studies with long-term average spectrum (LTAS) showed the importance of the glottal source for understanding the projected voices of actresses. In this study, electroglottographic (EGG) analysis was used to investigate the contribution of the glottal source to the projected voice, comparing actresses and nonactresses' voices, in different levels of intensity. Method: Thirty actresses and 30 nonactresses sustained vowels in habitual, moderate, and loud intensity levels. The EGG variables were contact quotient (CQ), closing quotient (QCQ), and opening quotient (QOQ). Other variables were sound pressure level (SPL) and fundamental frequency (F0). A KayPENTAX EGG was used. Variables were inputted in a general linear model. Results/Discussion: Actresses showed significantly higher values for SPL, in all levels, and both groups increased SPL significantly while changing from habitual to moderate and further to loud. There were no significant differences between groups for EGG quotients. There were significant differences between the levels only for F0 and CQ for both groups. Conclusion: SPL was significantly higher among actresses in all intensity levels, but in the EGG analysis, no differences were found. This apparently weak contribution of the glottal source in the supposedly projected voices of actresses, contrary to previous LTAS studies, might be because of a higher subglottal pressure or perhaps greater vocal tract contribution in SPL. Results from the present study suggest that trained subjects did not produce a significant higher SPL than untrained individuals by increasing the cost in terms of higher vocal fold collision and hence more impact stress. Future researches should explore the difference between trained and nontrained voices by aerodynamic measurements to evaluate the relationship between physiologic findings and the acoustic and EGG data. Moreover, further studies should consider both types of vocal tasks, sustained vowel and running speech, for both EGG and LTAS analysis. © 2013 The Voice Foundation.
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Objectives: Vocally trained actresses are expected to have more vocal economy than nonactresses. Therefore, we hypothesize that there will be differences in the electroglottogram-based voice economy parameter quasi-output cost ratio (QOCR) between actresses and nonactresses. This difference should remain across different levels of intensity. Methods: A total of 30 actresses and 30 nonactresses were recruited for this study. Participants from both groups were required to sustain the vowels /a/, /i/, and /u/, in habitual, moderate, and high intensity levels. Acoustic variables such as sound pressure level (SPL), fundamental frequency (F0), and glottal contact quotient (CQ) were obtained. The QOCR was then calculated. Results: There were no significant differences among the groups for QOCR. Positive correlations were observed for QOCR versus SPL and QOCR versus F0 in all intensity levels. Negative correlation was found between QOCR and CQ in all intensity levels. Considering the differences among intensity levels, from habitual to moderate and from moderate to loud, only the CQ did not differ significantly. The QOCR, SPL, and F0 presented significant differences throughout the different intensity levels. Conclusion: The QOCR did not reflect the level of vocal training when comparing trained and nontrained female subjects in the present study. Both groups demonstrated more vocal economy in moderate and high intensity levels owing to more voice output without an increase in glottal adduction. © 2013 The Voice Foundation.
Resumo:
Refugees from Sudan are the fastest growing community in Australia. Australian mental health professionals have to be prepared to offer services to this ethnic group along with the other mainstream and diverse consumers. In order to offer culturally competent services, these mental health professionals are required to be familiar with this emerging community. As such a review was undertaken with two main goals. Firstly, the review aimed to educate Australian mental health professionals about the demographics and culture of Sudan, the traumas encountered as a result of the civil war, factors leading to massive exodus, and the difficulties of the transit and post migration phase. Secondly, the review intended to inform Australian mental health professionals about the possible acculturation stress that is manifested in the form of intergeneration and role conflict and marital difficulties. The review highlights that there are few studies addressing acculturation stress of Sudanese refugees, and even fewer on the impact it has on relationships. Future research directions are discussed.
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Previous research has shown the association between stress and crash involvement. The impact of stress on road safety may also be mediated by behaviours including cognitive lapses, errors, and intentional traffic violations. This study aimed to provide a further understanding of the impact that stress from different sources may have upon driving behaviour and road safety. It is asserted that both stress extraneous to the driving environment and stress directly elicited by driving must be considered part of a dynamic system that may have a negative impact on driving behaviours. Two hundred and forty-seven public sector employees from Queensland, Australia, completed self-report measures examining demographics, subjective work-related stress, daily hassles, and aspects of general mental health. Additionally, the Driver Behaviour Questionnaire (DBQ) and the Driver Stress Inventory (DSI) were administered. All participants drove for work purposes regularly, however the study did not specifically focus on full-time professional drivers. Confirmatory factor analysis of the predictor variables revealed three factors: DSI negative affect; DSI risk taking; and extraneous influences (daily hassles, work-related stress, and general mental health). Moderate intercorrelations were found between each of these factors confirming the ‘spillover’ effect. That is, driver stress is reciprocally related to stress in other domains including work and domestic life. Structural equation modelling (SEM) showed that the DSI negative affect factor influenced both lapses and errors, whereas the DSI risk-taking factor was the strongest influence on violations. The SEMs also confirmed that daily hassles extraneous to the driving environment may influence DBQ lapses and violations independently. Accordingly, interventions may be developed to increase driver awareness of the dangers of excessive emotional responses to both driving events and daily hassles (e.g. driving fast to ‘blow off steam’ after an argument). They may also train more effective strategies for self-regulation of emotion and coping when encountering stressful situations on the road.
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A qualitative approach was used to explore the impact of acculturation stress on the marital relationships of South Sudanese refugees settled in Brisbane, Australia. Thirteen refugees, who were currently or previously married, participated in three gender specific focus groups. The perceived causes and possible solutions of conflict were thoroughly explored. Hypothetical scenarios were used to facilitate group discussion. Major issues causing conflict between couples were identified as: the management of finances and lack of family and social support. Several other areas of acculturation stress also emerged as factors associated with marital stress. There was a dissonance regarding the adherence to cultural gender roles. Freedom provided to women in Australia caused tension between the couples. Law enforcement officers were perceived as lacking cultural understanding and misinterpreting the couple distress. Finally, limited information provided to refugees pre and post migration was considered to hinder adjustment. The participants suggested a number of practical solutions to these issues which are potentially useful in guiding future refugee settlement programs.
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This study investigated the effect of a fear-based personality trait, as conceptualised in Gray’s revised reinforcement sensitivity theory (RST) by the strength of the fight/flight/freeze system (FFFS), on young people’s driving simulator performance under induced psychosocial stress. Seventy-one young drivers completed the Jackson-5 questionnaire of RST traits, followed by a psychosocial stress or relaxation induction procedure (random allocation to groups) and then a city driving simulator task. Some support was found for the hypothesis that higher FFFS sensitivity would result in poorer driving performance under stress, in terms of significantly poorer hazard responses, possibly due to an increased attentional focus on the aversive cues inherent in the stress induction leaving reduced attentional capacity for the driving task. These results suggest that stress may lead to riskier driving behaviour in individuals with fearful RST personality styles.
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Compared the different patterns of stress reported by mothers of children (aged 5–12 yrs) with either a chronic physical illness (cystic fibrosis) or a chronic psychological disorder (autism), and children without a physical or psychological disorder. 24 mothers from each of these 3 groups completed a short form of the Questionnaire on Resources and Stress. Each clinical group exhibited different patterns of stressful response consistent with the nature of the disorder and the requirements of care imposed on the families. Autism contributed significantly more to family stress than did cystic fibrosis. The number of children in the family was not a significant variable. Implications for the development of family intervention programs are discussed
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BACKGROUND: Despite advancements in our understanding of the importance of stress reduction in achieving good health, we still only have limited insight into the impact of stress on cellular function. Recent studies have suggested that exposure to prolonged psychological stress may alter an individual's physiological responses, and contribute to morbidity and mortality. This paper presents an overview of the study protocol we are using to examine the impact of life stressors on lifestyle factors, health-related quality of life and novel and established biomarkers of stress in midlife and older Australian women.The primary aim of this study is to explore the links between chronic psychological stress on both subjective and objective health markers in midlife and older Australian women. The study examines the extent to which exposure frightening, upsetting or stressful events such as natural disasters, illness or death of a relative, miscarriage and relationship conflict is correlated with a variety of objective and subjective health markers.Methods/design: This study is embedded within the longitudinal Healthy Aging of Women's study which has collected data from midlife and older Australian women at 5 yearly intervals since 2001, and uses the Allostastic model of women's health by Groer and colleagues in 2010. The current study expands the focus of the HOW study and will assess the impact of life stressors on quality of life and clinical biomarkers in midlife and older Australian women to explain the impact of chronic psychological stress in women. DISCUSSION: The proposed study hypothesizes that women are at increased risk of exposure to multiple or repeated stressors, some being unique to women, and the frequency and chronicity of stressors increases women's risk of adverse health outcomes. This study aims to further our understanding of the relationships between stressful life experiences, perceived quality of life, stress biomarkers, chronic illness, and health status in women.
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Objective To examine the impact of applying for funding on personal workloads, stress and family relationships. Design Qualitative study of researchers preparing grant proposals. Setting Web-based survey on applying for the annual National Health and Medical Research Council (NHMRC) Project Grant scheme. Participants Australian researchers (n=215). Results Almost all agreed that preparing their proposals always took top priority over other work (97%) and personal (87%) commitments. Almost all researchers agreed that they became stressed by the workload (93%) and restricted their holidays during the grant writing season (88%). Most researchers agreed that they submitted proposals because chance is involved in being successful (75%), due to performance requirements at their institution (60%) and pressure from their colleagues to submit proposals (53%). Almost all researchers supported changes to the current processes to submit proposals (95%) and peer review (90%). Most researchers (59%) provided extensive comments on the impact of writing proposals on their work life and home life. Six major work life themes were: (1) top priority; (2) career development; (3) stress at work; (4) benefits at work; (5) time spent at work and (6) pressure from colleagues. Six major home life themes were: (1) restricting family holidays; (2) time spent on work at home; (3) impact on children; (4) stress at home; (5) impact on family and friends and (6) impact on partner. Additional impacts on the mental health and well-being of researchers were identified. Conclusions The process of preparing grant proposals for a single annual deadline is stressful, time consuming and conflicts with family responsibilities. The timing of the funding cycle could be shifted to minimise applicant burden, give Australian researchers more time to work on actual research and to be with their families.
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Stress is implicated in the development and course of psychotic illness, but the factors that influence stress levels are not well understood. The aim of this study was to examine the impact of neuropsychological functioning and coping styles on perceived stress in people with first-episode psychosis (FEP) and healthy controls (HC). Thirty-four minimally treated FEP patients from the Early Psychosis Prevention and Intervention Centre, Melbourne, Australia, and 26 HC participants from a similar demographic area participated in the study. Participants completed a comprehensive neuropsychological test battery as well as the Coping Inventory for Stressful Situations (task-, emotion- and avoidance-focussed coping styles) and Perceived Stress Scale (PSS). Linear regressions were used to determine the contribution of neuropsychological functioning and coping style to perceived stress in the two groups. In the FEP group, higher levels of emotion-focussed and lower levels of task-focussed coping were associated with elevated stress. Higher premorbid IQ and working memory were also associated with higher subjective stress. In the HC group, higher levels of emotion-focussed coping, and contrary to the FEP group, lower premorbid IQ, working memory and executive functioning, were associated with increased stress. Lower intellectual functioning may provide some protection against perceived stress in FEP.
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Workplace stress has been an increasing concern in the construction industry. Workers are working longer hours and construction managers’ responsibilities are becoming more complex and complicated due to reduced resources and widespread stakeholder involvements. These additional pressures potentially trigger workplace stress and impact on project performance. The purpose of this study is to examine and advance understanding of stress and its impact relationships that support holistic and strategic stress management. 17 key stress sources are identified with their impact relationships on different stress types examined. Based on the research findings, this paper concludes with a Stressor-Stress-Performance relationships map.
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Rupture of vulnerable atheromatous plaque in the carotid and coronary arteries often leads to stroke and heart attack respectively. The mechanism of blood flow and plaque rupture in stenotic arteries is still not fully understood. A three dimensional rigid wall model was solved under steady state conditions and unsteady conditions by assuming a time-varying inlet velocity profile to investigate the relative importance of axial forces and pressure drops in arteries with asymmetric stenosis. Flow-structure interactions were investigated for the same geometry and the results were compared with those retrieved with the corresponding 2D cross-section structural models. The Navier-Stokes equations were used as the governing equations for the fluid. The tube wall was assumed hyperelastic, homogeneous, isotropic and incompressible. The analysis showed that the three dimensional behavior of velocity, pressure and wall shear stress is in general very different from that predicted by cross-section models. Pressure drop across the stenosis was found to be much higher than shear stress. Therefore, pressure may be the more important mechanical trigger for plaque rupture other than shear stress, although shear stress is closely related to plaque formation and progression.
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While significant research has been undertaken exploring the pedagogical benefits of undertaking lengthy social work and human services field placements, there has been very little consideration regarding the potential financial stress involved for students. This study has addressed this knowledge gap. Research was conducted in 2014 using quantitative and qualitative methods with students, academic and professional staff from six Queensland Universities. The findings show a significant relationship between unpaid placements and financial hardship creating considerable stress for students and at times a compromised learning experience whilst on placement. The limited flexibility in the requirements of professional bodies and universities for how placements are undertaken has been identified as a key contributor to financial hardship. Addressing the complexities inherent in this issue requires a collaborative effort from multiple stakeholders and should not be regarded as a problem for students to endure and manage.