Search results for: intermediate principal stress
4826 Impact of Acculturation Stress and Work-Family Conflict on the Health and Wellbeing of African Immigrants in the US: A Case Study of Ghanaian Immigrants
Authors: Rodlyn Remina Hines
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Africans who migrate to the United States (U.S.) go through an acculturation period. When they join the U.S. workforce during the period they are still acquainting to the new geographic area and culture, they may experience work and family conflict in addition to the stressors of acculturation. This study investigated the impact of acculturation stress and work-family conflict on the health and wellbeing of African immigrants in the U.S. using a growing immigrant population. Ghanaian immigrants (n = 100, males= 43%; females= 56%) residing in New York and Massachusetts, United States (U.S.), were recruited via purposive sampling to investigate the role acculturation stress and work-family conflict play on the health and wellbeing of African immigrants in the U.S. Using the Sociocultural theory, three hypotheses were proposed: (1) High acculturation stress will lead to high work-family conflict, (2) High work-family conflict will result in poor health and wellbeing, and (3) Work-family conflict will mediate the relationship between acculturation stress and health and wellbeing. The results fully supported the first hypothesis and partially supported the second and third. High acculturation stress led to high work-family conflict. Although high work-family conflict resulted in poorer health and wellbeing, high family support mediated work-family conflict and health and wellbeing. Participants who reported poor health also reported a lack of family or other support and those who reported strong family or other support also reported excellent health and wellbeing even with high work-family conflict. The latter group did not expect their health and wellbeing to get worse. I draw on these findings to conclude that African immigrants in the U.S. experience significant acculturation stress and work-family conflict resulting in poor health and wellbeing during their acculturation period if there is a lack of family or other support. These findings have implications for practitioners and policymakers.Keywords: acculturation stress, work-family conflict, Ghanaian immigrants, health and wellbeing
Procedia PDF Downloads 734825 The Antioxidant Effect of Vitamin C against Oxidative Stress Generate by Dietary Zn-Deficiency in Diabetic Rats
Authors: Zine Kechrid
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This study was carried out to investigate the antioxidant effect of vitamin C on oxidative stress induced by dietary Zn-deficiency in albino diabetic rats. Thirty two males alloxan-diabetic rats divided into two groups of 16 individuals each; the first group was fed a zinc adequate diet (54 mg zinc/kg). The second group had given low zinc diet (1 mg zinc/kg). Then, half of each group was treated with vitamin C (1 g/l) in drinking water. After four weeks, animals were sacrificed and different parameters were determined. The findings showed that dietary deficiency zinc intake significantly increased serum glucose. Zn-deficiency was also led to an increase in oxidative stress, which was indicated by an increase of MDA level and glutathione-S-transferase activity. Meanwhile it was result in a decrease of reduced glutathione (GSH) content, glutathione peroxidase GSH-Px and catalase activities in liver. However, the administration of vitamin C restored all the previous parameters approximately to their normal values. In conclusion, vitamin C probably played a key role strong as antioxidant factor against oxidative stress provoked by dietary zinc inadequate. Therefore, it might be contributed in reduction diabetes complications.Keywords: vitamin C, oxidative stress, zinc, experimental diabetes, rats
Procedia PDF Downloads 4054824 Non-Physician Medical Worker Experience during the COVID-19 Pandemic
Authors: William Mahony, L. Jacqueline Hirth, Richard Rupp, Sandra Gonzalez, Roger Zoorob
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Background: The impact of the COVID-19 pandemic on physicians has been considered by many researchers, but less is known about non-physician healthcare workers. The aim of this study is to examine the association of COVID-19 safety training and communication with stress. Methods: A 91-item online survey was distributed, starting January 2, 2021, to non-physician healthcare workers, including physician assistants, nurse practitioners, and medical assistants (MAs) in the United States through email and social media. A $1 donation was made to the Red Cross for each completed survey. The survey consisted of demographics, occupational questions, and perceived stress (perceived stress scale, PSS). Items on the PSS were combined for an overall score and categorized according to the severity of perceived stress. Chi-square tests were performed for bivariate analyses of categorical variables. Results: Of the 284 participants consenting to complete the survey, 197 participants completed the full survey. MAs made up most of the sample at 79%. Among all respondents, 47% had moderate PSS scores (scored between 14 and 26), and 51% had severe PSS scores (scored between 27 and 40). Unvaccinated participants reported statistically significantly lower levels of perceived stress (p = 0.002). Performing tasks outside of typical job responsibilities was not associated with PSS scores (p = .667). Discussion: Non-physician healthcare workers demonstrated a high level of perceived stress overall. The association between vaccination status and perceived stress should be examined in order to evaluate whether vaccination levels could be improved with further education about the virus and associated risks.Keywords: COVID-19, SARS-Cov-2, nursing, public health
Procedia PDF Downloads 1674823 Appraisal of Oxidative Stress in Pregnant and Non-Pregnant Non Descript Goat from Arid Tracts in India
Authors: Sudha Summarwar, Sudesh Agarwal, Deepali Lall, Nalini Kataria, Jyotsana Pandey
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Assessment of antioxidant status is an effective tool to appraise the presence of oxidative stress. A combination of assays can be used to evaluate the antioxidant status like serum catalase (CAT), superoxide dismutase (SOD) and monoamine oxidase (MAO). In human medicine pregnancy is known to be associated with oxidative stress. Oxidative stress produces harmful effects to the developing foetus. Several metabolic changes occur in the maternal body to meet the demand of energy of developing foetus. Due to these changes susceptibility of maternal body increases to oxidative stress. There is paucity of research work on this aspect in nondescript goats. Therefore, the present study was intended to appraise the oxidative stress in pregnant and non-pregnant non-descript goat. Blood samples were collected for serum separation in otherwise healthy pregnant and non-pregnant nondescript goats. Mean values of serum CAT, SOD and MAO were found on a higher side (p≤0.05) with serum SOD values showing a rise of 2.5 times higher than the control healthy value. Correlations among all the three parameters were found to be highly significant (p≤0.01) especially greatest in youngest group of pregnant animals. Illustration of result enlightened the veracity of bumped up production of free radicals in pregnant animals. Technical savoir-faire of oxidative stress supervision is essential for upholding of health status of foetus. The upshot of present study undoubtedly implied the development of oxidative stress in pregnant goats on the basis of altered antioxidant status. These findings conclude that initially the oxidative stress due to pregnancy is critically combated by the intricate defensive mechanism of natural antioxidant system of the body. It appears that this imbalance between oxidant and antioxidant must be checked in time to prevent cellular damage by regularly appraising the antioxidant status through laboratory methods.Keywords: antioxidant, oxidative stress, pregnancy, serum catalase
Procedia PDF Downloads 3284822 Approximate Solution of Some Mixed Boundary Value Problems of the Generalized Theory of Couple-Stress Thermo-Elasticity
Authors: Manana Chumburidze, David Lekveishvili
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We have considered the harmonic oscillations and general dynamic (pseudo oscillations) systems of theory generalized Green-Lindsay of couple-stress thermo-elasticity for isotropic, homogeneous elastic media. Approximate solution of some mixed boundary value problems for finite domain, bounded by the some closed surface are constructed.Keywords: the couple-stress thermoelasticity, boundary value problems, dynamic problems, approximate solution
Procedia PDF Downloads 5024821 Response of Barley Quality Traits, Yield and Antioxidant Enzymes to Water-Stress and Chemical Inducers
Authors: Emad Hafez, Mahmoud Seleiman
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Two field experiments were carried out in order to investigate the effect of chemical inducers [benzothiadiazole 0.9 mM L-1, oxalic acid 1.0 mM L-1, salicylic acid 0.2 mM L-1] on physiological and technological traits as well as on yields and antioxidant enzyme activities of barley grown under abiotic stress (i.e. water surplus and deficit conditions). Results showed that relative water content, leaf area, chlorophyll and yield as well as technological properties of barley were improved with chemical inducers application under water surplus and water-stress conditions. Antioxidant enzymes activity (i.e. catalase and peroxidase) were significantly increased in barley grown under water-stress and treated with chemical inducers. Yield and related parameters of barley presented also significant decrease under water-stress treatment, while chemical inducers application enhanced the yield-related traits. Starch and protein contents were higher in plants treated with salicylic acid than in untreated plants when water-stress was applied. In conclusion, results show that chemical inducers application have a positive interaction and synergetic influence and should be suggested to improve plant growth, yield and technological properties of water stressed barley. Salicylic acid application was better than oxalic acid and benzothiadiazole in terms of plant growth and yield improvement.Keywords: antioxidant enzymes, drought stress, Hordeum vulgare L., quality, yield
Procedia PDF Downloads 2944820 FEM for Stress Reduction by Optimal Auxiliary Holes in a Loaded Plate with Elliptical Hole
Authors: Basavaraj R. Endigeri, S. G. Sarganachari
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Steel is widely used in machine parts, structural equipment and many other applications. In many steel structural elements, holes of different shapes and orientations are made with a view to satisfy the design requirements. The presence of holes in steel elements creates stress concentration, which eventually reduce the mechanical strength of the structure. Therefore, it is of great importance to investigate the state of stress around the holes for the safety and properties design of such elements. By literature survey, it is known that till date, there is no analytical solution to reduce the stress concentration by providing auxiliary holes at a definite location and radii in a steel plate. The numerical method can be used to determine the optimum location and radii of auxiliary holes. In the present work plate with an elliptical hole, for a steel material subjected to uniaxial load is analyzed and the effect of stress concentration is graphically represented .The introduction of auxiliary holes at a optimum location and radii with its effect on stress concentration is also represented graphically. The finite element analysis package ANSYS 11.0 is used to analyse the steel plate. The analysis is carried out using a plane 42 element. Further the ANSYS optimization model is used to determine the location and radii for optimum values of auxiliary hole to reduce stress concentration. All the results for different diameter to plate width ratio are presented graphically. The results of this study are in the form of the graphs for determining the locations and diameter of optimal auxiliary holes. The graph of stress concentration v/s central hole diameter to plate width ratio. The Finite Elements results of the study indicates that the stress concentration effect of central elliptical hole in an uniaxial loaded plate can be reduced by introducing auxiliary holes on either side of the central circular hole.Keywords: finite element method, optimization, stress concentration factor, auxiliary holes
Procedia PDF Downloads 4464819 First Principle-Based Dft and Microkinetic Simulation of Co-Conversion of Carbon Dioxide and Methane on Single Iridium Atom Doped Hematite with Surface Oxygen Defect
Authors: Kefale W. Yizengaw, Delele Worku Ayele, Jyh-Chiang Jiang
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The catalytic co-conversion of CO₂ and CH₄ to value-added compounds has become one of the promising approaches to addressing global climate change by having valuable fossil fuels. Thedirect co-conversion of CO₂ and CH₄ to value-added compounds is attractive but tremendously challenging because of both molecules' thermodynamic stability and kinetic inertness. In the present study, a single iridium atom doped and a single oxygen atom defect hematite (110)surface model catalyst, which can comprehend direct C–O coupling based on simultaneous activation of CO2 and CH4 was studied using density functional theory plus U (DFT + U)calculations. The presence of dual active sites on the Ir/Fe₂O₃(110)-OV surface catalyst enablesCO₂ activation on the Ir site and CH₄ activation at the defect site. The electron analysis for the theco-adsorption of CO₂ and CH₄ deals with the electron redistribution on the surface and clearly shows the synergistic effect for simultaneous CO₂ and CH₄ activation on Ir/α- Fe₂O₃(110)-OVsurface. The microkinetic analysis shows that the dissociation of CH4 to CH3 * and H* plays an excellent role in the C–O coupling. The coverage analysis for the intermediate products of the microkinetic simulation results indicates that C–O coupling is the reaction limiting step. Finally, after the CH₃O* intermediate product species is produced, the radical hydrogen species spontaneously diffuse to the CH3O* intermediate product to form methanol at around 490 [K]. The present work provides mechanistic and kinetic insights into the direct C–O coupling of CO₂and CH₄, which could help design more-efficient catalysts.Keywords: co-conversion, C–O coupling, doping, oxygen vacancy, microkinetic
Procedia PDF Downloads 1084818 Principal Components Analysis of the Causes of High Blood Pressure at Komfo Anokye Teaching Hospital, Ghana
Authors: Joseph K. A. Johnson
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Hypertension affects 20 percent of the people within the ages 55 upward in Ghana. Of these, almost one-third are unaware of their condition. Also at the age of 55, more men turned to have hypertension than women. After that age, the condition becomes more prevalent with women. Hypertension is significantly more common in African Americans of both sexes than the racial or ethnic groups. This study was conducted to determine the causes of high blood pressure in Ashanti Region, Ghana. The study employed One Hundred and Seventy (170) respondents. The sample population for the study was all the available respondents at the time of the data collection. The research was conducted using primary data where convenience sampling was used to locate the respondents. A set of questionnaire were used to gather the data for the study. The gathered data was analysed using principal component analysis. The study revealed that, personal description, lifestyle behavior and risk awareness as some of the causes of high blood pressure in Ashanti Region. The study therefore recommend that people must be advice to see to their personal characteristics that may contribute to high blood pressure such as controlling of their temper and how to react perfectly to stressful situations. They must be educated on the factors that may increase the level of their blood pressure such as the essence of seeing a medical doctor before taking in any drug. People must also be made known by the public health officers to those lifestyles behaviour such as smoking and drinking of alcohol which are major contributors of high blood pressure.Keywords: high blood pressure, principal component analysis, hypertension, public health
Procedia PDF Downloads 4794817 The Role of Psychological Resilience in Predicting Psychological Distress in Kuwaiti Adults during Corona Varies Pandemic
Authors: Al-Tammar M. Shahah
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Background and Objective: A novel pneumonia caused by coronavirus disease 2019 (COVID-19), which is spreading domestically and internationally, has been identified by the Chinese city of Wuhan since the end of December 2019. Limited studies examined the psychological experience such as anxiety, depression, and stress during Corona pandemic. Moreover, to the best of author's knowledge, there is no study to date has examined the psychological resilience and mental health during Corona pandemic in Kuwait. Therefore, the present research investigates the role of psychological resilience in predicting psychological distress among Kuwaiti adults during Corona pandemic. Method: Kuwaiti citizens (N = 735) completed an online survey, which includes four scales the Hospital Anxiety and Depression Scale HADS (anxiety and depression), the Connor-Davidson Resilience Scale (CD-RISC-25), and the Perceived Stress Scale (PSS). A cross-sectional correlational design was used. Results: A high level of stress was observed, with 59% reported moderate to severe stress. In contrast, low levels of anxiety and depression were observed; with 70% reporting no anxiety symptoms and 74% report no depression symptoms. Psychological resilience was negatively correlated with anxiety, depression, and stress, consistent with previous studies. As expected, resilience was found to account for significant variance in anxiety and stress after controlling for quarantine variables and demographic variables. Conclusion: The findings suggest that increasing psychological resilience might help reduce psychological distress after confronting with stressful live events in Kuwaiti citizen.Keywords: anxiety, corona, depression, psychological resilience, stress
Procedia PDF Downloads 1164816 The Impact of Task-Based Language Teaching on Iranian Female Intermediate EFL Learners’ Writing Performance
Authors: Gholam Reza Parvizi, Hossein Azad, Ali Reza Kargar
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This article investigated the impact of task-based language teaching (TBLT) on writing performance of the Iranian intermediate EFL learners. There were two groups of forty students of the intermediate female learners studying English in Jahad-e-Daneshgahi language institute, ranging in age from thirteen to nineteen. They participated in their regular classes in the institute and were assigned to two groups including an experimental group of task-based language teaching and a control group for the purpose of homogeneity, all students in two groups took an achievement test before the treatment. As a pre-test; students were assigned to write a task at the beginning of the course. One of the classes was conducted through talking a TBLT approach on their writing, while the other class followed regular patterns of teaching, namely traditional approach for TBLT group. There were some tasks chosen from learners’ textbook. The task selection was in accordance with learning standards for ESL and TOFEL writing sections. At the end of the treatment, a post-test was administered to both experimental group and the control group. Scoring was done on the basis of scoring scale of “expository writing quality scale”. The researcher used paired samples t-test to analyze the effect of TBLT teaching approach on the writing performance of the learners. The data analysis revealed that the subjects in TBLT group performed better on the writing performance post-test than the subjects in control group. The findings of the study also demonstrated that TBLT would enhance writing performance in the group of learners. Moreover, it was indicated that TBLT has been effective in teaching writing performance to Iranian EFL learnersKeywords: task-based language teaching, task, language teaching approach, writing proficiency, EFL learners
Procedia PDF Downloads 4184815 Latitudinal Patterns of Pre-industrial Human Cultural Diversity and Societal Complexity
Authors: Xin Chen
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Pre-industrial old-world human cultural diversity and societal complexity exhibits remarkable geographic regularities. Along the latitudinal axis from the equator to the arctic, a descending trend of human ethno-cultural diversity is found to be in coincidence with a descending trend of biological diversity. Along the same latitudinal axis, the pre-industrial human societal complexity shows to peak at the intermediate latitude. It is postulated that human cultural diversity and societal complexity are strongly influenced by collective learning, and that collective learning is positively related to human population size, social interactions, and environmental challenges. Under such postulations the relationship between collective learning and important geographical-environmental factors, including climate and biodiversity/bio-productivity is examined. A hypothesis of intermediate bio-productivity is formulated to account for those latitudinal patterns of pre-industrial human societal complexity.Keywords: cultural diversity, soetal complexity, latitudinal patterns, biodiversity, bio-productivity, collective learning
Procedia PDF Downloads 744814 Investigating the Demand of Short-Shelf Life Food Products for SME Wholesalers
Authors: Yamini Raju, Parminder S. Kang, Adam Moroz, Ross Clement, Alistair Duffy, Ashley Hopwell
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Accurate prediction of fresh produce demand is one the challenges faced by Small Medium Enterprise (SME) wholesalers. Current research in this area focused on limited number of factors specific to a single product or a business type. This paper gives an overview of the current literature on the variability factors used to predict demand and the existing forecasting techniques of short shelf life products. It then extends it by adding new factors and investigating if there is a time lag and possibility of noise in the orders. It also identifies the most important factors using correlation and Principal Component Analysis (PCA).Keywords: demand forecasting, deteriorating products, food wholesalers, principal component analysis, variability factors
Procedia PDF Downloads 5124813 Parenting a Child with Mental Health Problems: The Role of Self-compassion
Authors: Vered Shenaar-Golan, Nava Wald, Uri Yatzkar
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Background: Parenting children with mental health problems poses multiple challenges, including coping with difficult behavior and negative child emotions. The impact on parents includes financial strain, negative social stigma, and negative feelings of guilt or blame, resulting in significant stress and lower levels of well-being. Given findings that self-compassion plays a significant role in reducing stress and improving well-being, the current study examined the role of self-compassion in the experience of parents raising a child with mental health problems. The study tested (1) whether child behavioral/emotional problem severity is associated with higher parental stress and lower parental well-being; (2) whether self-compassion is associated with lower parental stress and higher parental well-being; and (3) whether self-compassion is a stronger predictor of parental stress and well-being than child behavioral/emotional problem severity. Methods: Three hundred and six mothers and two hundred and fifty-six fathers of children attending a hospital child and adolescent psychiatric center were assessed at admission. Consenting parents completed four questionnaires: Child Strength and Difficulty – parent version, Self-compassion, Parent Feeling Inventory, and Well-Being. Results: Child behavioral/emotional problem severity was associated with higher parental stress and lower parental well-being, and self-compassion was a stronger predictor of parental stress and well-being levels than child behavioral/emotional problem severity. For children with internalizing but not externalizing behavioral/emotional problems, parental self-compassion was the only predictor of parental well-being beyond the severity of child behavioral/emotional problems. Conclusions: Cultivating self-compassion is important in reducing parental stress and increasing parental well-being, particularly with internalizing presentations, and should be considered when designing therapeutic interventions for parents.Keywords: parenting children with mental health problems, self-compassion, parental stress, feelings, well-being
Procedia PDF Downloads 744812 A Cross-Sectional Study on Smartphone Addiction, Sleep Hygiene, and Perceived Stress
Authors: Kriti Singh, Saurabh Tripathi, Pankaj Chaudhary, Abid Ali Ansari, Seema Nigam
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Introduction: The introduction of android and iOS has changed our lives dramatically over the past few years. The new generation is more dependent on their mobile phones for carrying out their daily pursuits. Smartphones have revolutionized our lives. The cutdown in rates of mobile network services has been affecting us drastically. A new type of dependence is seen among the people for Smartphones. A cross-sectional study was conducted to determine the state of addiction among the group of medical students, along with its association with sleep hygiene and anxiety. Material and Method: Study included 50 individuals in the age group of 18-35 years. Smartphone Addiction Scale Short Version, Sleep Hygiene Index, and Perceived Stress Scales were used conducting the study. Results: Mean age of 22 years (12%). The majority of subjects were 20-year olds (15 out of 50), the majority were males with few females. Mean Smartphone addiction score 39 (very severe), Mean Sleep Hygiene Index score 26.76 (moderate maladaptive hygiene and Mean Perceived Stress score of 19.92 (moderate stress). Conclusion: In majority students were found to have a very severe Smartphone Addiction with moderate sleep hygiene and a moderate level of perceived stress. The Smartphone was being used was for surfing social media applications.Keywords: addiction perceived stress, sleep hygiene index, smartphone
Procedia PDF Downloads 1274811 Comparison of Accumulated Stress Based Pore Pressure Model and Plasticity Model in 1D Site Response Analysis
Authors: Saeedullah J. Mandokhail, Shamsher Sadiq, Meer H. Khan
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This paper presents the comparison of excess pore water pressure ratio (ru) predicted by using accumulated stress based pore pressure model and plasticity model. One dimensional effective stress site response analyses were performed on a 30 m deep sand column (consists of a liquefiable layer in between non-liquefiable layers) using accumulated stress based pore pressure model in Deepsoil and PDMY2 (PressureDependentMultiYield02) model in Opensees. Three Input motions with different peak ground acceleration (PGA) levels of 0.357 g, 0.124 g, and 0.11 g were used in this study. The developed excess pore pressure ratio predicted by the above two models were compared and analyzed along the depth. The time history of the ru at mid of the liquefiable layer and non-liquefiable layer were also compared. The comparisons show that the two models predict mostly similar ru values. The predicted ru is also consistent with the PGA level of the input motions.Keywords: effective stress, excess pore pressure ratio, pore pressure model, site response analysis
Procedia PDF Downloads 2214810 Methadone Maintenance Treatment Patients' and Medical Students' Common Trait: Low Mindfulness Trait Associated with High Perceived Stress
Authors: Einat Peles, Anat Sason, Ariel Claman, Gabriel Barkay, Miriam Adelson
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Individuals with opioid addiction are characterized as suffering from stress responses disturbance, including the hypothalamic-pituitary-adrenal (HPA) axis, and autonomic nervous system function. HPA axis is known to be stabilized during methadone maintenance treatment (MMT). Mindfulness (present-oriented, nonjudgmental awareness of cognitions, emotions, perceptions, and habitual behavioral reactions in daily life) counteracts stress. To our knowledge, the relation between perceived stress and mindfulness trait among MMT patients has never been studied. To measure indices of mindfulness and their relation to perceived stress among MMT patients, a cross-sectional random sample of current MMT patients was performed using questionnaires for perceived stress (PSS) and mindfulness trait (FFMQ- yields a total score and individual scores for five internally consistent mindfulness factors: Observing, Describing, Acting with awareness and consciousness, Non-judging the inner experience, Non-reactivity to the inner experience). Two additional groups were studied to serve as reference groups; Medical students that are known to suffer from stress, and Axis II psychiatric diagnosis patients that are known to characterized with poor mindfulness trait. Results: Groups included 41 MMT patients, 27 Axis II patients and 36 medical students. High perceived stressed (PSS≥18) defined among 61% of the MMT patients and 50% of the medical students. Highest mindfulness score observed among non-stressed MMT patients (153.5±17.2) followed by the groups of stressed MMT and non-stressed student (128.9±17.0 and 130.5±13.3 respectively), with the lowest score among stressed students (116.3±17.9) (multivariate analyses, corrected model p (F=14.3) < 0.0005, p (group) < 0.0005, p (stress) < 0.0005, p (interaction) =0.2). Linear inverse correlations were found between perceived stress score and mindfulness score among MMT patients (R=-0.65, p < 0.0005) and students (R=-0.51, p=0.002). Axis II patients had the lowest mindfulness score (103.4±25.3). Conclusion: High prevalence of high perceived stressed which characterized with poor mindfulness trait observed in both MMT patients and medical students, two different population groups. The effectiveness of mindfulness treatment in reducing stress and improve mindfulness trait should be evaluated to improve rehabilitation of MMT patients, and students success.Keywords: mindfulness, stress, methadone maintenance treatment, medical students
Procedia PDF Downloads 1804809 The Effect of Combined Fluid Shear Stress and Cyclic Stretch on Endothelial Cells
Authors: Daphne Meza, Louie Abejar, David A. Rubenstein, Wei Yin
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Endothelial cell (ECs) morphology and function is highly impacted by the mechanical stresses these cells experience in vivo. Any change in the mechanical environment can trigger pathological EC responses. A detailed understanding of EC morphological response and function upon subjection to individual and simultaneous mechanical stimuli is needed for advancement in mechanobiology and preventive medicine. To investigate this, a programmable device capable of simultaneously applying physiological fluid shear stress (FSS) and cyclic strain (CS) has been developed, characterized and validated. Its validation was performed both experimentally, through tracer tracking, and theoretically, through the use of a computational fluid dynamics model. The effectiveness of the device was evaluated through EC morphology changes under mechanical loading conditions. Changes in cell morphology were evaluated through: cell and nucleus elongation, cell alignment and junctional actin production. The results demonstrated that the combined FSS-CS stimulation induced visible changes in EC morphology. Upon simultaneous fluid shear stress and biaxial tensile strain stimulation, cells were elongated and generally aligned with the flow direction, with stress fibers highlighted along the cell junctions. The concurrent stimulation from shear stress and biaxial cyclic stretch led to a significant increase in cell elongation compared to untreated cells. This, however, was significantly lower than that induced by shear stress alone, indicating that the biaxial tensile strain may counteract the elongating effect of shear stress to maintain the shape of ECs. A similar trend was seen in alignment, where the alignment induced by the concurrent application of shear stress and cyclic stretch fell in between that induced by shear stress and tensile stretch alone, indicating the opposite role shear stress and tensile strain may play in cell alignment. Junctional actin accumulation was increased upon shear stress alone or simultaneously with tensile stretch. Tensile stretch alone did not change junctional actin accumulation, indicating the dominant role of shear stress in damaging EC junctions. These results demonstrate that the shearing-stretching device is capable of applying well characterized dynamic shear stress and tensile strain to cultured ECs. Using this device, EC response to altered mechanical environment in vivo can be characterized in vitro.Keywords: cyclic stretch, endothelial cells, fluid shear stress, vascular biology
Procedia PDF Downloads 3744808 Calculation of Stress Intensity Factors in Rotating Disks Containing 3D Semi-Elliptical Cracks
Authors: Mahdi Fakoor, Seyed Mohammad Navid Ghoreishi
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Initiation and propagation of cracks may cause catastrophic failures in rotating disks, and hence determination of fracture parameter in rotating disks under the different working condition is very important issue. In this paper, a comprehensive study of stress intensity factors in rotating disks containing 3D semi-elliptical cracks under the different working condition is investigated. In this regard, after verification of modeling and analytical procedure, the effects of mechanical properties, rotational velocity, and orientation of cracks on Stress Intensity Factors (SIF) in rotating disks under centrifugal loading are investigated. Also, the effects of using composite patch in reduction of SIF in rotating disks are studied. By that way, the effects of patching design variables like mechanical properties, thickness, and ply angle are investigated individually.Keywords: stress intensity factor, semi-elliptical crack, rotating disk, finite element analysis (FEA)
Procedia PDF Downloads 3584807 The Short-Term Stress Indicators in Home and Experimental Dogs
Authors: Madara Nikolajenko, Jevgenija Kondratjeva
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Stress is a response of the body to physical or psychological environmental stressors. Cortisol level in blood serum is determined as the main indicator of stress, but the blood collection, the animal preparation and other activities can cause unpleasant conditions and induce increase of these hormones. Therefore, less invasive methods are searched to determine stress hormone levels, for example, by measuring the cortisol level saliva. The aim of the study is to find out the changes of stress hormones in blood and saliva in home and experimental dogs in simulated short-term stress conditions. The study included clinically healthy experimental beagle dogs (n=6) and clinically healthy home American Staffordshire terriers (n=6). The animals were let into a fenced area to adapt. Loud drum sounds (in cooperation with 'Andžeja Grauda drum school') were used as a stressor. Blood serum samples were taken for sodium, potassium, glucose and cortisol level determination and saliva samples for cortisol determination only. Control parameters were taken immediately before the start of the stressor, and next samples were taken immediately after the stress. The last measurements were taken two hours after the stress. Electrolyte levels in blood serum were determined using direction selective electrode method (ILab Aries analyzer) and cortisol in blood serum and saliva using electrochemical luminescence method (Roche Diagnostics). Blood glucose level was measured with glucometer (ACCU-CHECK Active test strips). Cortisol level in the blood increased immediately after the stress in all home dogs (P < 0,05), but only in 33% (P < 0,05) of the experimental dogs. After two hours the measurement decreased in 83% (P < 0,05) of home dogs (in 50% returning to the control point) and in 83% (P < 0,05) of the experimental dogs. Cortisol in saliva immediately after the stress increased in 50% (P > 0,05) of home dogs and in 33% (P > 0,05) of the experimental dogs. After two hours in 83% (P > 0,05) of the home animals, the measurements decreased, only in 17% of the experimental dogs it decreased as well, while in 49% measurement was undetectable due to the lack of material. Blood sodium, potassium, and glucose measurements did not show any significant changes. The combination of short-term stress indicators, when, after the stressor, all indicators should immediately increase and decrease after two hours, confirmed in none of the animals. Therefore the authors can conclude that each animal responds to a stressful situation with different physiological mechanisms and hormonal activity. Cortisol level in saliva and blood is released with the different speed and is not an objective indicator of acute stress.Keywords: animal behaivor, cortisol, short-term stress, stress indicators
Procedia PDF Downloads 2604806 Free Fatty Acid Assessment of Crude Palm Oil Using a Non-Destructive Approach
Authors: Siti Nurhidayah Naqiah Abdull Rani, Herlina Abdul Rahim, Rashidah Ghazali, Noramli Abdul Razak
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Near infrared (NIR) spectroscopy has always been of great interest in the food and agriculture industries. The development of prediction models has facilitated the estimation process in recent years. In this study, 110 crude palm oil (CPO) samples were used to build a free fatty acid (FFA) prediction model. 60% of the collected data were used for training purposes and the remaining 40% used for testing. The visible peaks on the NIR spectrum were at 1725 nm and 1760 nm, indicating the existence of the first overtone of C-H bands. Principal component regression (PCR) was applied to the data in order to build this mathematical prediction model. The optimal number of principal components was 10. The results showed R2=0.7147 for the training set and R2=0.6404 for the testing set.Keywords: palm oil, fatty acid, NIRS, regression
Procedia PDF Downloads 4994805 Determining the Relationship Between Maternal Stress and Depression and Child Obesity: The Mediating Role of Maternal Self-efficacy
Authors: Alireza Monzavi Chaleshtori, Mahnaz Aliakbari Dehkordi, Maryam Aliakbari, Solmaz Seyed Mostafaii
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Objective: Considering the growing obesity among children and the role of mother's psychological factors as well as the need to prevent childhood obesity, this study aimed to investigate the mediating role of mother's self-efficacy in the relationship between mother's stress and depression and child obesity. Method: For this purpose, in a descriptive-correlation study, 222 mothers and children aged 1 to 5 years in Tehran, who had the opportunity to answer an online questionnaire, were selected by random sampling and to the depression scales of the Kroenke and Spitzer Patient Health Questionnaire, Cohen's stress and Self-efficacy of Berkeley mothers answered. Pearson correlation test and path analysis were used for data analysis. Findings: The findings showed that maternal depression had an indirect and significant effect on child obesity, and the effect of stress and depression on child obesity was indirect and non-significant. Therefore, the model has a good fit with the research data, and stress and depression indirectly predicted child obesity with the mediating role of self-efficacy. Conclusion: The hypothesized model tested based on mother's stress and depression with the mediating role of mother's self-efficacy was a good model in explaining the prediction of child obesity. Based on the findings of this research, a practical framework can be provided to explain the psychological factors of the mother in relation to child obesity and its treatment.Keywords: stress, self-efficacy, child obesity, depression
Procedia PDF Downloads 614804 Air Quality Forecast Based on Principal Component Analysis-Genetic Algorithm and Back Propagation Model
Authors: Bin Mu, Site Li, Shijin Yuan
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Under the circumstance of environment deterioration, people are increasingly concerned about the quality of the environment, especially air quality. As a result, it is of great value to give accurate and timely forecast of AQI (air quality index). In order to simplify influencing factors of air quality in a city, and forecast the city’s AQI tomorrow, this study used MATLAB software and adopted the method of constructing a mathematic model of PCA-GABP to provide a solution. To be specific, this study firstly made principal component analysis (PCA) of influencing factors of AQI tomorrow including aspects of weather, industry waste gas and IAQI data today. Then, we used the back propagation neural network model (BP), which is optimized by genetic algorithm (GA), to give forecast of AQI tomorrow. In order to verify validity and accuracy of PCA-GABP model’s forecast capability. The study uses two statistical indices to evaluate AQI forecast results (normalized mean square error and fractional bias). Eventually, this study reduces mean square error by optimizing individual gene structure in genetic algorithm and adjusting the parameters of back propagation model. To conclude, the performance of the model to forecast AQI is comparatively convincing and the model is expected to take positive effect in AQI forecast in the future.Keywords: AQI forecast, principal component analysis, genetic algorithm, back propagation neural network model
Procedia PDF Downloads 2184803 The Mechanical and Electrochemical Properties of DC-Electrodeposited Ni-Mn Alloy Coating with Low Internal Stress
Authors: Chun-Ying Lee, Kuan-Hui Cheng, Mei-Wen Wu
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The nickel-manganese (Ni-Mn) alloy coating prepared from DC electrodeposition process in sulphamate bath was studied. The effects of process parameters, such as current density and electrolyte composition, on the cathodic current efficiency, microstructure, internal stress and mechanical properties were investigated. Because of its crucial effect on the application to the electroforming of microelectronic components, the development of low internal stress coating with high leveling power was emphasized. It was found that both the coating’s manganese content and the cathodic current efficiency increased with the raise in current density. In addition, the internal stress of the deposited coating showed compressive nature at low current densities while changed to tensile one at higher current densities. Moreover, the metallographic observation, X-ray diffraction measurement, transmission electron microscope (TEM) examination, and polarization curve measurement were conducted. It was found that the Ni-Mn coating consisted of nano-sized columnar grains and the maximum hardness of the coating was associated with (111) preferred orientation in the microstructure. The grain size was refined along with the increase in the manganese content of the coating, which accordingly, raised its hardness and mechanical tensile strength. In summary, the Ni-Mn coating prepared at lower current density of 1-2 A/dm2 had low internal stress, high leveling power, and better corrosion resistance.Keywords: Ni-Mn coating, DC plating, internal stress, leveling power
Procedia PDF Downloads 3644802 Physical, Microstructural and Functional Quality Improvements of Cassava-Sorghum Composite Snacks
Authors: Adil Basuki Ahza, Michael Liong, Subarna Suryatman
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Healthy chips now dominating the snack market shelves. More than 80% processed snack foods in the market are chips. This research takes the advantages of twin extrusion technology to produce two types of product, i.e. directly expanded and intermediate ready-to-fry or microwavable chips. To improve the functional quality, the cereal-tuber based mix was enriched with antioxidant rich mix of temurui, celery, carrot and isolated soy protein (ISP) powder. Objectives of this research were to find best composite cassava-sorghum ratio, i.e. 60:40, 70:30 and 80:20, to optimize processing conditions of extrusion and study the microstructural, physical and sensorial characteristics of the final products. Optimization was firstly done by applying metering section of extruder barrel temperatures of 120, 130 and 140 °C with screw speeds of 150, 160 and 170 rpm to produce direct expanded product. The intermediate product was extruded in 100 °C and 100 rpm screw speed with feed moisture content of 35, 40 and 45%. The directly expanded products were analyzed for color, hardness, density, microstructure, and organoleptic properties. The results showed that interaction of ratio of cassava-sorghum and cooking methods affected the product's color, hardness, and bulk density (p<0.05). Extrusion processing conditions also significantly affected product's microstructure (p<0.05). The direct expanded snacks of 80:20 cassava-sorghum ratio and fried expanded one 70:30 and 80:20 ratio shown the best organoleptic score (slightly liked) while baking the intermediate product with microwave were resulted sensorial not acceptable quality chips.Keywords: cassava-sorghum composite, extrusion, microstructure, physical characteristics
Procedia PDF Downloads 2774801 Nonlinear Finite Element Analysis of Concrete Filled Steel I-Girder Bridge
Authors: Waheed Ahmad Safi, Shunichi Nakamura
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Concrete filled steel I-girder (CFIG) bridge was proposed and the bending and shear strength was confirmed by experiments. The area surrounded by the upper and lower flanges and the web is filled with concrete in CFIG, which is used to the intermediate support of a continuous girder. Three-dimensional finite element models were established to simulate the bending and shear behaviors of CFIG and to clarify the load transfer mechanism. Steel plates and filled concrete were modeled as a three-dimensional 8-node solid element and steel reinforcement bars as a three-dimensional 2-node truss element. The elements were mostly divided into the 50 x 50 mm mesh size. The non-linear stress-strain relation is assumed for concrete in compression including the softening effect after the peak, and the stress increases linearly for concrete in tension until concrete cracking but then decreases due to tension stiffening effect. The stress-strain relation for steel plates was tri-linear and that for reinforcements was bi-linear. The concrete and the steel plates were rigidly connected. The developed FEM model was applied to simulate and analysis the bending behaviors of the CFIG specimens. The vertical displacements and the strains of steel plates and the filled concrete obtained by FEM agreed very well with the test results until the yield load. The specimens collapsed when the upper flange buckled or the concrete spalled off. These phenomena cannot be properly analyzed by FEM, which produces a small discrepancy at the ultimate states. The FEM model was also applied to simulate and analysis the shear tests of the CFIG specimens. The vertical displacements and strains of steel and concrete calculated by FEM model agreed well with the test results. A truss action was confirmed by the FEM and the experiment, clarifying that shear forces were mainly resisted by the tension strut of the steel plate and the compression strut of the filled concrete acting in the diagonal direction. A trail design with the CFIG was carried out for a four-span continuous highway bridge and the design method was established. Construction cost was estimated about 12% lower than that of a conventional steel I-section girder.Keywords: concrete filled steel I-girder, bending strength, FEM, limit states design, steel I-girder, shear strength
Procedia PDF Downloads 2104800 Coping Strategies for Stress Used by Adolescent Girls in Riyadh, Saudi Arabia
Authors: Hafsa Raheel
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Objectives: Secondary school girls, ages 15–19 years old were surveyed to find out the coping strategies they used when stressed. Adolescents, who are affected with stress and depression early in life, suffer from depression throughout their lives, especially if they are utilizing improper ways to cope with it. Methods: A cross-sectional school-based survey among 1028 adolescent girls was conducted among the secondary schools in Riyadh city, Kingdom of Saudi Arabia. Results: About 25% stated that they cry, 19% listen to music, 15% start eating a lot, 12% sit alone/isolate themselves, 11% pray/read the Quran, 10% get into a verbal argument or a fight. Only a few, 3% exercise, and 2% stated that they find someone to discuss and talk to. Conclusion: The majority of the adolescent girls in our survey rely on emotion-related coping mechanisms rather than problem-solving mechanisms. This can cause long-term implications in these adolescents as there is an increased probability to develop depression later on in life. Policy makers need to implement strategies for early identification of stress and depression. Talking to friends and family can serve as an effective way to cope with stress.Keywords: adolescents, stress, Saudi Arabia, mental health
Procedia PDF Downloads 2624799 Study of Variation in Linear Growth and Other Parameters of Male Albino Rats on Exposure to Chronic Multiple Stress after Birth
Authors: Potaliya Pushpa, Kataria Sushma, D. S. Chowdhary, Dadhich Abhilasha
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Introduction: Stress is a nonspecific response of the body to a stressor or triggering stimulus. Chronic stress exposure contributes to various remarkable alterations o growth and development. Collective effects of stressors lead to several changes which are physical, physiological and behavioral in nature. Objective: To understand on an animal model how various chronic stress affect the somatic body growth as it can be useful for effective stress treatment and prevention of stress related illnesses. Material and Method: By selective fostering only male pup colonies were made and 102 male albino rats were studied. They were divided two groups as Control and Stressed. The experimental groups were exposed to four major types of stress as maternal deprivation, Restraint stress, electric foot shock and noise stress for affecting emotional, physical and physiological activities. Exposure was from birth to 17 week of life. Roentgenographs were taken in two planes as Dorso-ventral and Lateral and then measured for each rat. Various parameters were observed at specific intervals. Parameters recorded were Body weight and for linear growth it was summation of Cranial length, Head rump length and tail length. Behavior changes were also observed. Result: Multiple chronic stresses resulted in loss of approx. 25% of mean body weight. Maximal difference was found on 119th day (i.e. 87.81 gm) between the control and stressed group. Linear growth showed retardation which was found to be significant in stressed group on statistical analysis. Cranial Length and Head-rump Length showed maximum difference after maternal deprivation stress. After maternal deprivation (Day 21) and electric foot shock (Day 101) maximum difference i.e. 0.39 cm and 0.47 cm were found in cranial length of two groups. Electric foot shock had considerable impact on tail length. Noise Stress affected moreover behavior as compact to physical growth. Conclusion: Collective study showed that chronic stress not only resulted in reduced body weight in albino rats but also total linear size of rat thus affecting whole growth and development.Keywords: stress, microscopic anatomy, macroscopic anatomy, chronic multiple stress, birth
Procedia PDF Downloads 2624798 Simulation the Stress Distribution of Wheel/Rail at Contact Region
Authors: Norie A. Akeel, Z. Sajuri, A. K. Ariffin
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This paper discusses the effect of different loading analysis on crack initiation life of wheel/rail in the contact region. A simulated three dimensional (3D) elasto plastic model of a wheel/rail contact is modeled using the fine mesh technique in the contact region by using Finite Element Method FEM code ANSYS 11.0 software. Different loads of approximately from 70 to 140 KN was applied on the wheel tread through the running surface on the railhead surface to simulate stress distribution (Von Mises) and a life prediction of the crack initiation under rolling contact motion. Stress analysis is achieved and the fatigue life to the rail head surface is calculated numerically by using a multi-axial fatigue life of crack initiation model. All results obtained from the previous researches are compared with this research.Keywords: FEM, rolling contact, rail track, stress distribution, fatigue life
Procedia PDF Downloads 5504797 The Relationship Between Weight Gain, Cyclicality of Diabetologic Education and the Experienced Stress: A Study Involving Pregnant Women
Authors: Agnieszka Rolinska, Marta Makara-Studzinska
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Introduction: In recent years, there has been an intensive development of research into the physiological relationships between the experienced stress and obesity. Moreover, strong chronic stress leads to the disorganization of a person’s activeness on various levels of functioning, including the behavioral and cognitive sphere (also in one’s diet). Aim: The present work addresses the following research questions: Is there a relationship between an increase in stress related to the disease and the need for the cyclicality of diabetologic education in gestational diabetes? Are there any differences in terms of the experienced stress during the last three months of pregnancy in women with gestational diabetes and in normal pregnancy between the patients with normal weight gains and those with abnormal weight gains? Are there any differences in terms of stress coping styles in women with gestational diabetes and in normal pregnancy between the patients with normal weight gains and those with abnormal weight gains? Method: The study involved pregnant women with gestational diabetes (treated with diet, without insulin therapy) and in normal pregnancy – 206 women in total. The following psychometric tools were employed: Perceived Stress Scale (PSS; Cohen, Kamarck, Mermelstein), Coping Inventory for Stressful Situations (CISS; Endler, Parker) and authors’ own questionnaire. Gestational diabetes mellitus was diagnosed on the basis of the results of fasting oral glucose tolerance test (75 g OGTT). Body weight measurements were confirmed in a diagnostic interview, taking into account medical data. Regularities in weight gains in pregnancy were determined according to the recommendations of the Polish Gynecological Society and American norms determined by the Institute of Medicine (IOM). Conclusions: An increase in stress related to the disease varies in patients with differing requirements for the cyclical nature of diabetologic education (i.e. education which is systematically repeated). There are no differences in terms of recently experienced stress and stress coping styles between women with gestational diabetes and those in normal pregnancy. There is a relationship between weight gains in pregnancy and the stress experienced in life as well as stress coping styles – both in pregnancy complicated by diabetes and in physiological pregnancy. In the discussion of the obtained results, the authors refer to scientific reports from English-language magazines of international range.Keywords: diabetologic education, gestational diabetes, stress, weight gain in pregnancy
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