22 resultados para detailed balance
em Brock University, Canada
Resumo:
SUMMARY Background: Age related declines in lower extremity strength have been associated with impaired mobility and changes in gait patterns, which increase the likelihood of falls. Since community dwelling adults encounter a wide range of locomotor challenges including uneven and obstmcted walking surfaces, we examined the effect of a strength 11 and balance exercise program on obstructed walking in postmenopausal women. Objectives: This study examined the effect of a weighted-vest strength and balance exercise program on adaptations of the stance leg during obstacle walking in postmenopausal women. Methods: Eighteen women aged 44-62 years who had not engaged in regular resistance training for the past year were recruited from the St. Catharines community to participate in this study. Eleven women volunteered for an aerobic (walking), strength, and balance training program 3 times per week for 12 weeks while 7 women volunteered as controls. Measurements included: force platform dynamic balance measure of the center of pressure (COP) and ground reaction forces (GRFs) in the stance leg while going over obstacles of different heights (0,5, 10,25 and 30 cm); and isokinetic strength measures of knee and ankle extension and flexion. Results: Of the 18 women, who began the trial, 16 completed it. The EX group showed a significant increase of 40% in ankle plantar flexion strength (P < 0.05). However, no improvements in measures of COP or GRFs were observed for either group. Failure to detect any changes in measures of dynamic balance may be due to small sample size. Conclusions: Postmenopausal women experience significant improvements in ankle strength with 12 weeks of a weighted-vest balance and strength training program, however, these changes do not seem to be associated with any improvement in measures of dynamic balance.
Resumo:
This r\.~et.lrch examined ho\\' ~ight \\'omen artists \\'ho t~ach at the uni versity and college level, balance thcir artistic practic~ and their institu tional responsibilities as tcachers. This thesis reprt.~ents the culmination of \\'ork for my second graduate degree. For my first degrCt! on th~ grad uat~ level, I concentratoo on d~veloping my artistic practice. This ~Iaster's Degree in Education is no k~ important to m~. In pursuing studies in the field of education I \\'anted to understand my rol~ as both an educator and an artist and in the process I uncovered the interplay of race, class, and gender at \\'ork in th~ classroom. Coming from a \\'orking-class, immigrant background \\'here higher education \vas vie\\'cd as a stepping stone that \"ould enable my siblings and me a greater spectrum of opportunities, I \\'as at last able to understand my o\\'n educational experiences, more clearly. I discovered ho\\' d\.~ply I internalized the racism, sexism and class discrimination, I submitted to in my history as a student. Becoming a\\'are about the social forc\.~ at "'ork \\'ithin my day to day life has provided me \\'ith instruments \\'hich I can usc to examine and respond to these inequities as I confront them in th~ future. This \,'ork exists as a serk'S of responses and further av~nues for investigation on some themes I first began to explor~, albeit very tentati\'~ly, during my first incarnation as a graduate student and so though the h\'o bound volum~s rna-\' one da.v sit si.d~ b\' s id~ on the bookshelf, th~\-' exist in the context of my life as a set of brackets surrounding a series of qUl'Stions about being a \\'Onlan, a teachcr and an artist.
Resumo:
This thesis investigated attention focus and balance control in eighteen healthy young adults and eighteen healthy older adults. All participants performed sixteen consecutive trials of a balance task which involved standing for 30-s on an unstable platform that could rotate only in the roll direction. There were no attention focus instructions provided on any of the sixteen trials. Following the completion of the initial and final attempt in the series, participants reported "where" their attention had been focused when performing the task. The results showed differences in balance between young and older adults and improvements in balance with practice in both young and older adults. However, there were no differences in attention focus strategies between young and older adults. Both age groups directed attention to multiple sources during the balance task. An equal focus on internal (i.e., feet, trunk, and other body parts) and external (i.e., the platform) sources with little focus on events not related to the task dominated on the first attempt of the balance task. Focus on internal sources was maintained and focus on events not related to the task increased at the expense of focus on external sources on the final attempt of the balance task. Following the series of sixteen trials to establish "natural" attention focus, participants performed three randomly presented trials, each with specific attention focus instructions (i.e., think about minimizing movements of the feet, the trunk, or the platform). The results showed that, in contrast to the literature, instructions to focus on an internal source, the trunk, actually augmented control of the task as reflected in reduced trunk sway whereas instructions to focus on an internal source, the feet, or an external source, the platform, did not benefit performance on the task. Thus, the distance fi-om the interaction point of the body with the external source is critical and may not depend on whether the source is internal or external. Thus, a global attention focus instruction may not be beneficial and the nature of the task should be considered when adopting attention focus instructions for young and older adults.
Resumo:
Dyadic friendShip' asymmetry was examined in relation to gender, friendship quality, and friendship status. Sixty-nine grade five children and their mutual, same-sex, friends participated in a laboratory session comprised ofvarious activities and completed questionnaires to identify mutual friends and evaluate friendship quality. Asymmetry of power was assessed observationally during an origami task. Variations in balance of power were evident in children's friendships. Boys' dyads had significantly greater levels of asymmetry than girls' dyads. Regardless of gender, asymmetry was associated with lower friendship quality, particularly as indexed by validation and caring and conflict resolution. Asymmetry was unrelated to differences in friendship status. Furthermore, relative individual power within the friendship was not related to individual perceptions offriendship quality. The implications ofthese findings in the theoretical and empirical literature were considered and suggestions for future research were made.
Resumo:
The purpose ofthis study was to explore the perceptions of wellness and bidance amongst female health care professionals negotiating career, family aiul continuing education commitments. Five women who met the criteria of having a family (with children), holding a full-time professional career in health care, and who were presently pursuing continuing education were interviewed. This paper begins with the introduction to the topic of research and the questions to be answered. The review of literature explores the theory and research A^ch precede this study and addresses the surrounding areas of: wellness, balance, multiple roles, stress and continuing education. < This study has assumed a qualitative, phenomenological approach. The data collected through the use of individual interviews were analyzed using a two-part process. Analysis using both (a) methodological interpretation and (b) The Listening Guide method has allowed for the uncovering of major themes, and the portrayal of each participant's unique experience. Some of the major themes which emerged from this research include: wellness as multidimensional and fluctuating, making personal sacrifices, the presence of stress, professional as a vital role, and continuing education as something for me. Perhaps the most significant finding this research has identified is the positive role continuing education can hold in the lives of women already negotiating multiple commitments. The notion that continuing education can act as a means of enhancing perceptions of wellness and balance holds a number of implications in theory, practice, and for future research.
Resumo:
Proponents of Basic Needs Theory (BNT; Deci & Ryan, 2002) contend that the mechanism underpinning psychological well-being is the fulfillment of basic psychological needs with their fulfillment addressed in an independent (Deci & Ryan, 2002) or balanced manner (Sheldon & Niemiec, 2006). The purpose of this investigation was to explore the associations between the fulfillment of basic psychological needs and two forms of psychological well-being, namely hedonic and eudaimonic indices. Employing purposive sampling and a cross-sectional design, collegiate volleyball players (N = 219; nfemales = 127) completed a battery of self-report instruments assessing psychological need satisfaction and well-being toward the mid-to-end portion oftheir competitive season. Aligned with BNT (Deci & Ryan, 2002) tenets and study hypotheses, results demonstrated that basic psychological need fulfillment was associated with psychological well-being in the context of volleyball. Albeit minimal, balanced need fulfillment was generally predictive of well-being indices beyond independent need contributions with suppressor effects noted. In sum, the results of the present investigation generally coincide with previous sport based BNT (e.g., Reinboth & Duda, 2006) and balanced need satisfaction (e.g., Sheldon & Niemiec, 2006) literature. Additional BNT support has been garnished and suggests that the fulfillment of the basic psychological needs for competence, autonomy, and relatedness may be targeted as the mechanisms to facilitate athletes' psychological well-being. Along with Ryan and Deci's (2007) recommendations, the outcomes of this investigation highlight the need for further empirical study ofBNT's tenets in the realm of sport including assessments of balanced need satisfaction as well as varied hedonic and eudaimonic indices.
Resumo:
The current thesis investigated the effects of a 12-week multifactorial exercise and balance training program on balance control in older adults. Participants completed a baseline testing session which included a series of questionnaires, anthropometric measures, and 18 stance and walking tests. Those who were randomly assigned to the exercise group participated in the 12-week training program while the comparison group was asked not to change anything in his/her lifestyle during the 12-week control period, but were invited to participate in the training program after his/her control period. The same testing protocol was repeated after the 12-week period. The results indicated that there were improvements in the time to complete the walking tests but no change in trunk sway in both the exercise and comparison groups. No changes in stance durations or trunk sway were observed. The findings suggest that the current training program showed no significant improvement in balance control in healthy older adults.
Resumo:
The human neuromuscular system is susceptible to changes within the thermal environment. Cold extrinsic temperatures can significantly reduce muscle and nervous system function and communication, which can have consequences for motor performance. A repeated measures design protocol exposed participants to a 12°C cold water immersion (CWI) up to the ankle, knee, and hip to determine the effect that reduced skin and muscle temperature had on balance and strength task execution. Although a linear reduction in the ability to perform balance tasks was seen from the control condition through to the hip CWI, results from the study indicated a significant reduction in dynamic balance (Star Excursion Balance Test reach distance) performance from only the hip CWI (P<0.05). This reduced performance could have been due to an increase in joint stiffness, increased agonist-antagonist co-contraction, and/or reduced isokinetic muscular strength. Reduced physical performance due to cold temperature could negatively impact outdoor recreational athletics.
Resumo:
Traditional employment options for persons with developmental disabilities are lacking. Employment options available for persons with developmental disabilities are reflective of the medical and social model perspectives of disability; with segregated and supported employment reinforcing the idea that persons with developmental disabilities are incapable and competitive employment missing the necessary accommodations for persons to be successful. This study examined social enterprises as an alternative employment option that can balance both medical and social model perspectives by accommodating for weaknesses or limitations and recognizing the strengths and capabilities of persons with developmental disabilities in the workplace. Moreover, this study is part of a broader case study which is examining the nature and impacts of a social enterprise, known as Common Ground Co-operative (CGC), which supports five social purpose businesses that are owned and operated by persons with developmental disabilities. This study is part of the Social Business and Marginalized Social Groups Community-University Research Alliance. To date, a case study has been written describing the nature and impacts of CGC and its related businesses from the perspectives of the Partners, board members, funders and staff (Owen, Readhead, Bishop, Hope & Campbell, in press & Readhead, 2012). The current study used a descriptive case study approach to provide a detailed account of the perceptions and opinions of CGC staff members who support each of the Partners in the five related businesses. Staff members were chosen for the focus of this study because of the integral role that they play in the successful outcomes of the persons they support. This study was conducted in two phases. In the first phase five staff members were interviewed. During this stage of interviews, several themes were presented which needed to be examined in further detail, specifically staff stress and burnout and duty of care for business Partners versus the promotion of their autonomy. A second phase of interviews was then conducted with one individual participant and a focus group of seven. During both interview phases, Staff participants described an employment model that creates a non-judgemental environment for the business Partners that promotes their strengths, accommodates for their limitations, provides educational opportunities and places the responsibility for the businesses on the persons with developmental disabilities cultivating equality and promoting independence. Staff described the nature of their role including risk factors for stress, the protective factors that buffer stress, and the challenges associated with balancing many role demands. Issues related to the replication of this social enterprise model are described.
Resumo:
Wine produced using an appassimento-type process represents a new and exciting innovation for the Ontario wine industry. This process involves drying grapes that have already been picked from the vine, which increases the sugar content due to dehydration and induces a variety of changes both within and on the surface of the grapes. Increasing sugar contents in musts subject wine yeast to conditions of high osmolarity during alcoholic fermentations. Under these conditions, yeast growth can be inhibited, target alcohol levels may not be attained and metabolic by-products of the hyperosmotic stress response, including glycerol and acetic acid, may impact wine composition. The further metabolism of acetic acid to acetylCoA by yeast facilitates the synthesis of ethyl acetate, a volatile compound that can also impact wine quality if present in sufficiently high concentrations. The first objective of this project was to understand the effect of yeast strain and sugar concentration on fermentation kinetics and metabolite formation, notably acetic acid and ethyl acetate, during fermentation in appassimento-type must. Our working hypotheses were that (1) the natural isolate Saccharomyces bayanus would produce less acetic acid and ethyl acetate compared to Saccharomyces cerevisiae strain EC-1118 fermenting the high and low sugar juices; (2) the wine produced using the appassimento process would contain higher levels of acetic acid and lower levels of ethyl acetate compared to table wine; (3) and the strains would be similar in the kinetic behavior of their fermentation performances in the high sugar must. This study determined that the S. bayanus strain produced significantly less acetic acid and ethyl acetate in the appassimento wine and table wine fermentations. Differences in acetic acid and ethyl acetate production were also observed within strains fermenting the two sugar conditions. Acetic acid production was higher in table wine fermented by S. bayanus as no acetic acid was produced in appassimento-style wine, and 1.4-times higher in appassimento wine fermented by EC-1118 over that found in table wine. Ethyl acetate production was 27.6-times higher in table wine fermented by S. bayanus, and 5.2-times higher by EC-1118, compared to that in appassimento wine. Sugar utilization and ethanol production were comparable between strains as no significant differences were determined. The second objective of this project was to bring a method in-house for measuring the concentration of pyridine nucleotides, NAD+, NADP+, NADH and NADPH, in yeast cytosolic extract. Development of this method is of applicative interest for our lab group as it will enable the redox balance of the NAD+/ NADH and NADP+/ NADPH systems to be assessed during high sugar fermentations to determine their respective roles as metabolic triggers for acetic acid production. Two methods were evaluated in this study including a UV-endpoint method using a set of enzymatic assay protocols outlined in Bergmeyer (1974) and a colorimetric enzyme cycling method developed by Sigma-Aldrich® using commercial kits. The former was determined to be limited by its low sensitivity following application to yeast extract and subsequent coenzyme analyses, while the latter was shown to exhibit greater sensitivity. The results obtained from the kits indicated high linearity, accuracy and precision of the analytical method for measuring NADH and NADPH, and that it was sensitive enough to measure the low coenzyme concentrations present in yeast extract samples. NADtotal and NADPtotal concentrations were determined to be above the lower limit of quantification and within the range of the respective calibration curves, making this method suitable for our research purposes.
Resumo:
This project is about a reflective research journey taken by a Masters student in the Child and Youth Studies Department at Brock University in St. Catharines Ontario. This journey consisted of a mixed method approach using the qualitative method of autoethnography along with the Indigenous research method of storytelling. The research was done using the concept of two-eyed seeing which consisted of trying to balance the two eyes of research: Indigenous and Western. The Non-Aboriginal researcher not only reflected on her own learning journey but also the lessons she learned from the voices of 48 women from Six Nations of the Grand River Territory. Like the trickster character Coyote, the researcher struggled, stumbled and was transformed by this journey.
Resumo:
Localized muscular fatigue has been identified to have detrimental effects on balance control, an important skill for everyday life. Manipulation of attention focus instructions has been shown to benefit performance of various motor skills including balance and has been found to facilitate endurance during fatiguing tasks. The purpose of this thesis was to determine if the use of attention focus instructions could attenuate the effects of muscular fatigue on balance control. Twenty-four participants performed a balance task (two-legged stance on an unstable platform) before and after a fatigue protocol. Trunk sway, platform excursions, and lower limb muscle activity was measured. Results suggest that use of either internal or external attention focus instructions can reduce the immediate effects of muscular fatigue of the lower limb on balance control as shown through reduced trunk sway and platform excursions. These results have relevance for individuals performing balance tasks in a fatigued state.
Resumo:
Diatoms are renowned for their robust ability to perform NPQ (Non-Photochemical Quenching of chlorophyll fluorescence) as a dissipative response to heightened light stress on photosystem II, plausibly explaining their dominance over other algal groups in turbulent light environs. Their NPQ mechanism has been principally attributed to a xanthophyll cycle involving the lumenal pH regulated reversible de-epoxidation of diadinoxanthin. The principal goal of this dissertation is to reveal the physiological and physical origins and consequences of the NPQ response in diatoms during short-term transitions to excessive irradiation. The investigation involves diatom species from different originating light environs to highlight the diversity of diatom NPQ and to facilitate the detection of core mechanisms common among the diatoms as a group. A chiefly spectroscopic approach was used to investigate NPQ in diatom cells. Prime methodologies include: the real time monitoring of PSII excitation and de-excitation pathways via PAM fluorometry and pigment interconversion via transient absorbance measurements, the collection of cryogenic absorbance spectra to measure pigment energy levels, and the collection of cryogenic fluorescence spectra and room temperature picosecond time resolved fluorescence decay spectra to study excitation energy transfer and dissipation. Chemical inhibitors that target the trans-thylakoid pH gradient, the enzyme responsible for diadinoxanthin de-epoxidation, and photosynthetic electron flow were additionally used to experimentally manipulate the NPQ response. Multifaceted analyses of the NPQ responses from two previously un-photosynthetically characterised species, Nitzschia curvilineata and Navicula sp., were used to identify an excitation pressure relief ‘strategy’ for each species. Three key areas of NPQ were examined: (i) the NPQ activation/deactivation processes, (ii) how NPQ affects the collection, dissipation, and usage of absorbed light energy, and (iii) the interdependence of NPQ and photosynthetic electron flow. It was found that Nitzschia cells regulate excitation pressure via performing a high amplitude, reversible antenna based quenching which is dependent on the de-epoxidation of diadinoxanthin. In Navicula cells excitation pressure could be effectively regulated solely within the PSII reaction centre, whilst antenna based, diadinoxanthin de-epoxidation dependent quenching was implicated to be used as a supplemental, long-lasting source of excitation energy dissipation. These strategies for excitation balance were discussed in the context of resource partitioning under these species’ originating light climates. A more detailed investigation of the NPQ response in Nitzschia was used to develop a comprehensive model describing the mechanism for antenna centred non-photochemical quenching in this species. The experimental evidence was strongly supportive of a mechanism whereby: an acidic lumen triggers the diadinoxanthin de-epoxidation and protonation mediated aggregation of light harvesting complexes leading to the formation of quencher chlorophyll a-chlorophyll a dimers with short-lived excited states; quenching relaxes when a rise in lumen pH triggers the dispersal of light harvesting complex aggregates via deprotonation events and the input of diadinoxanthin. This model may also be applicable for describing antenna based NPQ in other diatom species.
Resumo:
The effects of stress at work are estimated to cost Canadian employers more than 20 billion dollars annually through absenteeism, sick leave and decreased productivity. Over the past two decades, Canadians have reported higher stress levels, increased work hours and more work performed outside of normal business hours. This work-life imbalance has far-reaching repercussions–affecting an employee’s performance as well as their health. Chronic exposure to these high levels of stress can also lead to burnout. The primary purpose of this study was to determine the magnitude in which burnout symptoms influence the relationship between work-life balance and self-rated health. The secondary purpose of this study was to determine if gender and age interactions exist in the relationship between burnout, work-life balance, and self-rated health. This cross-sectional study involved secondary analysis of 220 managers, workers and human service professionals who completed an Occupational Health Clinics for Ontario Workers’ Mental Injury Toolkit (MIT) survey for the launch of the MIT. The MIT survey is a modified form of the short version of the Copenhagen Psychosocial Questionnaire and includes expanded questioning around burnout, stress, sleep troubles, cognitive, and somatic symptoms. There were no significant differences in self-rated health based on a respondent’s gender or age, indicating that no interaction of gender and age would be required. Respondents with low self-rated health reported significantly higher burnout and work-life imbalance compared to those with high self-rated health. The regression analysis demonstrated that the magnitude in which burnout mediates the relationship between work-life balance and self-rated health was 96%. These findings support previous studies that associate high levels of work-life imbalance or burnout with poor self-rated health or health outcomes. In this study, the shared variance between work-life balance and burnout also supports recent efforts to redefine the context and causes of burnout to include non-work factors. Based on our findings, the potential exists for the development of workplace health promotion strategies that address maintaining a balance between work and home as they may improve employee health and reduce burnout.
Resumo:
Annual meeting of the Long Point Company (1 page, printed) attached to a copy of the May 31, 1882 balance sheet (1 page, printed). The meeting has the name J.I. Mackenzie, assistant secretary-treasurer on the bottom and the balance sheet has the names J.I. Mackenzie, secretary treasurer and Geo. H. Gillespie, auditor on the bottom of the page, June 6, 1882.