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Estimation of Maximal Work Rate Based on the 6-Minute Walk Test and Fat-Free Mass in Chronic Obstructive Pulmonary Disease

Cavalheri, Vinicius; Hernandes, Nidia Aparecida; Camillo, Carlos Augusto; Probst, Vanessa Suziane; Ramos, Dionei; Pitta, Fabio
Fonte: W B Saunders Co-elsevier Inc Publicador: W B Saunders Co-elsevier Inc
Tipo: Artigo de Revista Científica Formato: 1626-1628
ENG
Relevância na Pesquisa
45.71%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 09/04246-9; Cavalheri V, Hernandes NA, Camillo CA, Probst VS, Ramos D, Pitta F. Estimation of maximal work rate based on the 6-minute walk test and fat-free mass in chronic obstructive pulmonary disease. Arch Phys Med Rehabil 2010; 91:1626-8.Objective: To propose a predictive equation of the maximal work rate (Wmax) in patients with chronic obstructive pulmonary disease (COPD) based on the product of 6-minute walking test (6MWT) and fat-free mass (FFM) and to compare it with a previously proposed equation based on the product of 6MWT and body weight (BW).Design: Descriptive (cross-sectional) study.Setting: University-based rehabilitation center.Participants: Patients with COPD (N=53; 30 men; forced expiratory volume in I second, 45%+/- 15% predicted).Interventions: Not applicable.Main Outcome Measures: Three Wmax were produced: Wmax_real (obtained from the maximal cycle ergometry test), Wmax_BW (estimated from the product of 6MWT and BW), previously proposed by Hill et al. (Arch Phys Med Rehabil 2008; 89(9):1782-7); and Wmax_FFM (estimated from the product of 6MWT and FFM).Results: The equation derived from a regression model to estimate Wmax_FFM was as follows: -27.9717+ 3.7792*(6MWT*FFM). Wmax_real correlated better with Wmax_FFM (r=.64) than with Wmax_BW (r=.54). There was no difference between Wmax_FFM (median [interquartile range]...

Influence of exercise mode and maximal lactate-steady-state concentration on the validity of OBLA to predict maximal lactate-steady-state in active individuals

Figueira, Tiago R.; Caputo, Fabrizio; Pelarigo, Jailton G.; Denadai, Benedito S.
Fonte: Sports Medicine Australia Publicador: Sports Medicine Australia
Tipo: Artigo de Revista Científica Formato: 280-286
ENG
Relevância na Pesquisa
45.79%
The aim of this study was to analyze the effects of exercise mode on the validity of onset of blood lactate accumulation (OBLA-3.5-mM fixed blood lactate concentration) to predict the work-rate at maximal lactate steady state (MLSSwork-rate). Eleven recreationally active mates (21.3 +/- 2.9 years, 72.8 +/- 6.7 kg, 1.78 +/- 0.1 m) performed randomly incremental tests to determine OBLA (stage duration of 3 min), and 2 to 4 constants work-rate exercise tests to directly determine maximal lactate steady state parameters on a cycle-ergometer and treadmill. For both exercise modes, the OBLA was significantly correlated to MLSSwork-rate, (cycling: r = 0.81 p = 0.002; running: r = 0.94, p < 0.001). OBLA (156.2 +/- 41.3 W) was lower than MLSSwork-rate (179.6 +/- 26.4 W) during cycling exercise (p = 0.007). However, for running exercise, there was no difference between OBLA (3.2 +/- 0.6 m s(-1)) and MLSSwork-rate (3.1 +/- 0.4 m s(-1)). The difference between OBLA and MLSSworkrate on the cycle-ergometer (r = 0.86; p < 0.001) and treadmill (r = 0.64; p = 0.048) was significantly related to the specific MLSS. We can conclude that the validity of OBLA on predicting MLSSwork-rate is dependent on exercise mode and that its disagreement is related to individual variations in MLSS. (C) 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Is maximal lactate steady state during intermittent cycling different for active compared with passive recovery?

Greco, Camila Coelho; Barbosa, Luis Fabiano; Carita, Renato Aparecido Correa; Denadai, Benedito Sergio
Fonte: Canadian Science Publishing, Nrc Research Press Publicador: Canadian Science Publishing, Nrc Research Press
Tipo: Artigo de Revista Científica Formato: 1147-1152
ENG
Relevância na Pesquisa
45.78%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The purpose of this study was to analyze the effect of recovery type (passive vs. active) during prolonged intermittent exercises on the blood lactate concentration (MLSS) and work rate (MLSSwint) at maximal lactate steady state. Nineteen male trained cyclists were divided into 2 groups for the determination of MLSSwint using passive (maximal oxygen uptake = 58.1 +/- 3.5 mL center dot kg(-1).min(-1); N = 9) or active recovery (maximal oxygen uptake = 60.3 +/- 9.0 mL center dot kg(-1).min(-1); N = 10). They performed the following tests, on different days, on a cycle ergometer: (i) incremental test until exhaustion to determine maximal oxygen uptake; (ii) 2 to 3 continuous submaximal constant work rate tests (CWRT) for the determination of the work rate at continuous maximal lactate steady state (MLSSwcont); and (iii) 2 to 3 intermittent submaximal CWRT (7 x 4 min and 1 x 2 min, with 2-min recovery) with either passive or active recovery for the determination of MLSSwint. MLSSwint was significantly higher when compared with MLSSwcont for both passive recovery (294.7 +/- 32.2 vs. 258.7 +/- 24.5 W...

Variabilidade da frequencia cardiaca em trabalhadores em turnos; Heart rate variability in shift workers

Priscila Standke da Costa
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 20/12/2006 PT
Relevância na Pesquisa
35.83%
O trabalho em turnos atinge de 15 a 20% da força de trabalho em países industrializados e tem sido associado com o aumento da incidência de doenças cardiovasculares. Ainda não está claro, mas a dessincronização dos ritmos circadianos do sistema nervoso autônomo cardíaco poderia explicar este fenômeno. Uma ferramenta não?invasiva para avaliar a atividade do sistema nervoso autônomo (SNA) é análise dos componentes temporais e espectrais da variabilidade da freqüência cardíaca (VFC), calculados a partir de um registro eletrocardiográfico de 24 horas. O objetivo deste trabalho foi analisar estes componentes em 32 enfermeiras saudáveis de um hospital universitário, engajadas em turnos fixos de trabalho (idade média de 35,62 ± 6,17 anos). As voluntárias foram divididas em três grupos de acordo com o horário de trabalho: matutino (7 às 13 h), vespertino (13 ás 19h) e noturno (19 ás 7 h) e submetidas a avaliação clínica, fisioterápica e funcional cardiorespiratória. Foram levantados dados relativos ao tempo de exposição, aos hábitos pessoais (atividade física e etilismo), histórico de doenças dos progenitores e antecedentes menstruais. Além disso, foi realizado um exame clínico com aferição dos sinais vitais de repouso (freqüências cardíaca e respiratória e a pressão arterial) e com coleta de amostras de sangue para caracterização de perfil lipídico. Na avaliação fisioterápica foram mensuradas as variáveis antropométricas de peso...

As condições de trabalho docente no ensino superior público no contexto das reformas educacionais brasileiras; The relations of teaching work in public superior education in the context of the Brazilian educational reforms

Emilia Peixoto Vieira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/07/2011 PT
Relevância na Pesquisa
45.62%
Esta tese analisa as condições de trabalho dos docentes do ensino superior público, considerando os movimentos de reforma da educação, entre o período compreendido de 1990 a 2007. A idéia de examinar essa temática deve-se ao fato de que o trabalho docente, no ensino superior, tem ocupado lugar de destaque na reforma educacional brasileira, assim como entre os estudos realizados nos últimos anos. As políticas educacionais brasileiras sugerem uma adequação do trabalho docente às novas exigências profissionais advindas das inovações tecnológicas e da conseqüente mudança no mundo do trabalho. Para compreensão das mudanças e justificativas que influenciam as políticas públicas para o ensino superior, realizamos um estudo empírico com professores da Universidade Federal do Espírito Santo - UFES a fim de conhecermos seus pontos de vista sobre o seu trabalho; como eles vivem o conjunto das alterações postas pela reforma do ensino superior; como percebem as mudanças que foram introduzidas na sua área específica; como se sentem perante as novas expectativas geradas pelo conjunto das reformulações para o ensino superior e se seu ritmo de trabalho foi, realmente, alterado. Todo esse conjunto de questões remete para a necessidade de reflexão sobre as relações de trabalho...

The effect of Gang Angle of Offset Disc Harrows on Soil Tilth, Work Rate and Fuel Consumption

Serrano, João M.; Peça, José M.; Pinheiro, Anacleto C.; Carvalho, Mário J.; Nunes, Mário C.; Ribeiro, Luís; Santos, Fernando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.81%
In offset disc harrows, the angle between gangs may be changed to meet the field conditions. Tractor drivers usually use an angle close to maximum, increasing power requirements and therefore limiting the forward speed and, consequently, the work rate. The objective of this work was to study, in the specific soil conditions present in Southern Portuguese agriculture, the effect of working with a disc harrow at a reduced gang angle and at a higher forward speed, in terms of work rate, fuel consumption per hectare and distribution of dry soil aggregates. A trailed type medium-weight offset disc harrow (20 discs of 610mm diameter) was used, pulled by a four wheel drive tractor. A portable computer based record system was used to collect engine speed, actual forward speed, slip, fuel consumption and draught force. Higher work rates and lower values of fuel consumption per hectare were attained, with no visible difference in soil tilth, by operating the disc harrow at a lower angle between disc gangs and shifting up to a higher gear ratio whilst maintaining engine speed. Tractor drivers, particularly those with tractors equipped with performance monitors should consider setting, by preliminary tests prior to the main field work, the right combination of gang angle and forward speed within the limits of quality of the work and the safety of the operation.

Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise

Gimenes,A.C.; Neder,J.A.; Dal Corso,S.; Nogueira,C.R.; Nápolis,L.; Mello,M.T.; Bulle,A.S.; Nery,L.E.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2011 EN
Relevância na Pesquisa
45.69%
We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption ( O2) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the O2 on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔO2/ΔWR slope was calculated up to GET (S1), above GET (S2) and over the entire linear portion of the response (S T). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak O2 and muscle performance were lower in patients than controls (P < 0.05). Patients had significantly lower ΔO2/ΔWR than controls...

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

Takara,L.S.; Cunha,T.M.; Barbosa,P.; Rodrigues,M.K.; Oliveira,M.F.; Nery,L.E.; Neder,J.A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 EN
Relevância na Pesquisa
45.69%
This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V CW) = rib cage (V RC) + abdomen (V AB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) V CW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of V CW regulation as EEV CW increased non-linearly in 17/30 "hyperinflators" and decreased in 13/30 "non-hyperinflators" (P < 0.05). EEV AB decreased slightly in 8 of the "hyperinflators", thereby reducing and slowing the rate of increase in end-inspiratory (EI) V CW (P < 0.05). In contrast, decreases in EEV CW in the "non-hyperinflators" were due to the combination of stable EEV RC with marked reductions in EEV AB. These patients showed lower EIV CW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIV CW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However...

Gas exchange responses to constant work rate exercise in chronic cardiac failure.

Riley, M; Pórszász, J; Stanford, C F; Nicholls, D P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1994 EN
Relevância na Pesquisa
45.71%
OBJECTIVE--To examine the time course of changes in minute oxygen consumption and other gas exchange variables and heart rate during constant work rate exercise in patients with chronic cardiac failure. DESIGN--Treadmill exercise with on line measurement of gas exchange and a target duration of 10 minutes. SUBJECTS--Seven men in New York Heart Association class II, six in class III, and seven controls. MAIN OUTCOME MEASURES--Gas exchange variables and heart rate were averaged for the final two minutes of exercise. Time constants were calculated for the increase in all variables. RESULTS--Consumption of oxygen at the end of exercise (VO2) was similar in class II patients (mean (95% confidence interval (95% CI) 14.9 (13.6 to 16.1) ml kg-1 min-1), class III patients (13.2 (11.2 to 15.1) ml kg-1 min-1), and controls (13.3 (12.5 to 14.2) ml kg-1 min-1). The patients reached this VO2 more slowly with longer exponential time constants of 0.82 (0.59 to 1.04) min in class II and 1.19 (0.86 to 1.51) min in class III, than the 0.49 (0.35 to 0.64) min in the controls. Time constants of other gas exchange variables and heart rate were also longer in patients. By analysis of covariance, peak VO2 accounted for the between group difference in the time constant for VO2...

Comparison of arterial potassium and ventilatory dynamics during sinusoidal work rate variation in man.

Casaburi, R; Stringer, W W; Singer, E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/06/1995 EN
Relevância na Pesquisa
45.8%
1. The mechanisms underlying the exercise hyperpnoea have been difficult to define. Recently it has been suggested that exercise ventilation (VE) changes in proportion to changes in arterial potassium concentration ([K+]a). Similar VE and [K+]a time courses following work rate changes have been cited as supporting evidence. This study compared [K+]a and VE dynamics during moderate exercise in man. 2. We observed VE and gas exchange responses in five healthy men to sinusoidal work rate variation between 25 and approximately 105 W. Tests of approximately 30 min duration were performed at sinusoidal periods of 9, 6 and 3 min and in the steady state. In each test, during two or three sine periods, arterial blood was sampled (24 per test) and analysed for [K+] and blood gases. Response amplitude and phase (relative to work rate) were determined for each variable. 3. [K+]a fluctuated in response to sinusoidal work rate forcing with mean-to-peak amplitude averaging 0.15 mmol 1(-1). However, among tests, VE amplitude and phase were not highly correlated with [K+]a (r = 0.36 and 0.67, respectively). Further, average [K+]a amplitude in the 9 and 6 min sinusoidal studies tended to exceed the steady-state amplitude, while average VE amplitude fell progressively with increasing forcing frequency. The dissimilar dynamics of [K+]a and VE seem inconsistent with a major role for [K+]a as a proportional controller of ventilation during non-steady state moderate exercise in man. 4. Among tests...

Assessing preference for reinforcers using demand curves, work-rate functions, and expansion paths

Tustin, R. Don
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1995 EN
Relevância na Pesquisa
45.74%
A behavioral economic model that explains the choice and allocation of work rate is used to predict performance patterns in three contexts: with single schedules, with concurrent schedules when total reinforcement is low, and with concurrent schedules when reinforcement increases. Performance in the three contexts is predicted to change in orderly ways depending on how the subject evaluates the reinforcers earned. Quadrant diagrams are used to generate reinforcer demand functions, work-rate supply functions, and reinforcement-rate expansion paths. Preference between reinforcers is viewed as being a variable, with preference reversing in some situations.

Effects of exercise-induced arterial hypoxaemia and work rate on diaphragmatic fatigue in highly trained endurance athletes

Vogiatzis, Ioannis; Georgiadou, Olga; Giannopoulou, Ifigenia; Koskolou, Maria; Zakynthinos, Spyros; Kostikas, Konstantinos; Kosmas, Epaminondas; Wagner, Harrieth; Peraki, Eleni; Koutsoukou, Antonia; Koulouris, Nickolaos; Wagner, Peter D; Roussos, Charis
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.78%
Diaphragmatic fatigue occurs in highly trained athletes during exhaustive exercise. Since approximately half of them also exhibit exercise-induced arterial hypoxaemia (EIAH) during high-intensity exercise, the present study sought to test the hypothesis that arterial hypoxaemia contributes to exercise-induced diaphragmatic fatigue in this population. Ten cyclists (: 70.0 ± 1.6 ml kg−1 min−1; mean ± s.e.m.) completed, in a balanced ordering sequence, one normoxic (end-exercise arterial O2 saturation (Sa,O2): 92 ± 1%) and one hyperoxic (FI,O2: 0.5% O2; Sa,O2: 97 ± 1%) 5 min exercise test at intensities equal to 80 ± 3 and 90 ± 3% of maximal work rate (WRmax), respectively, producing the same tidal volume (VT) and breathing frequency (f) throughout exercise. Cervical magnetic stimulation was used to determine reduction in twitch transdiaphragmatic pressure (Pdi,tw) during recovery. Hyperoxic exercise at 90% WRmax induced significantly (P = 0.022) greater post-exercise reduction in Pdi,tw (15 ± 2%) than did normoxic exercise at 80% WRmax (9 ± 2%), despite the similar mean ventilation (123 ± 8 and 119 ± 8 l min−1, respectively), breathing pattern (VT: 2.53 ± 0.05 and 2.61 ± 0.05 l, f: 49 ± 2 and 46 ± 2 breaths min−1...

Muscle [phosphocreatine] dynamics following the onset of exercise in humans: the influence of baseline work-rate

Jones, Andrew M; Wilkerson, Daryl P; Fulford, Jonathan
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.74%
The kinetics of pulmonary O2 uptake is known to be substantially slower when exercise is initiated from a baseline of lower-intensity exercise rather than from rest. However, it is not known whether putative intracellular regulators of mitochondrial respiration (and in particular the phosphocreatine concentration, [PCr]) show similar non-linearities in their response dynamics. The purpose of this study was therefore to investigate the influence of baseline metabolic rate on muscle [PCr] kinetics (as assessed using 31P-magnetic resonance spectroscopy) following the onset of exercise. Seven male subjects completed ‘step’ tests to heavy-intensity exercise (80% of peak work-rate) from a resting baseline and also from a baseline of moderate-intensity exercise (40% of peak work-rate) using a single-leg knee-extensor ergometer situated inside the bore of a 1.5 T super-conducting magnet. The time constant describing the kinetics of the initial exponential-like fall in [PCr] was significantly different between rest-to-moderate (25 ± 14 s), rest-to-heavy (48 ± 11 s) and moderate-to-heavy exercise (95 ± 40 s) (P < 0.05 for all comparisons). A delayed-onset ‘slow component’ in the [PCr] response was observed in all subjects during rest-to-heavy exercise...

Analyses of the Redistribution of Work following Cardiac Resynchronisation Therapy in a Patient Specific Model

Niederer, Steven Alexander; Lamata, Pablo; Plank, Gernot; Chinchapatnam, Phani; Ginks, Matt; Rhode, Kawal; Rinaldi, Christopher Aldo; Razavi, Reza; Smith, Nicolas Peter
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 28/08/2012 EN
Relevância na Pesquisa
35.83%
Regulation of regional work is essential for efficient cardiac function. In patients with heart failure and electrical dysfunction such as left branch bundle block regional work is often depressed in the septum. Following cardiac resynchronisation therapy (CRT) this heterogeneous distribution of work can be rebalanced by altering the pattern of electrical activation. To investigate the changes in regional work in these patients and the mechanisms underpinning the improved function following CRT we have developed a personalised computational model. Simulations of electromechanical cardiac function in the model estimate the regional stress, strain and work pre- and post-CRT. These simulations predict that the increase in observed work performed by the septum following CRT is not due to an increase in the volume of myocardial tissue recruited during contraction but rather that the volume of recruited myocardium remains the same and the average peak work rate per unit volume increases. These increases in the peak average rate of work is is attributed to slower and more effective contraction in the septum, as opposed to a change in active tension. Model results predict that this improved septal work rate following CRT is a result of resistance to septal contraction provided by the LV free wall. This resistance results in septal shortening over a longer period which...

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

Takara, L.S.; Cunha, T.M.; Barbosa, P.; Rodrigues, M.K.; Oliveira, M.F.; Nery, L.E.; Neder, J.A.
Fonte: Sociedade Brasileira de Medicina Tropical Publicador: Sociedade Brasileira de Medicina Tropical
Tipo: Artigo de Revista Científica
Publicado em 15/10/2012 EN
Relevância na Pesquisa
45.69%
This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(VCW) = rib cage (VRC) + abdomen (VAB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) VCW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of VCW regulation as EEVCW increased non-linearly in 17/30 “hyperinflators” and decreased in 13/30 “non-hyperinflators” (P < 0.05). EEVAB decreased slightly in 8 of the “hyperinflators”, thereby reducing and slowing the rate of increase in end-inspiratory (EI) VCW (P < 0.05). In contrast, decreases in EEVCW in the “non-hyperinflators” were due to the combination of stable EEVRC with marked reductions in EEVAB. These patients showed lower EIVCW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIVCW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However...

The effects of work choices on young people: an analysis of the impact of the Work Choices legislation on wages and working conditions of young workers in Australia

Worsley, Mitchell
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Relatório
Relevância na Pesquisa
35.83%
On 27 March 2006, the Federal Government's Workplace Relations Amendment (Work Choices) Act 2005, was enacted. This saw the most radical industrial relations change in Australia for over one hundred years. The changes included: removing unfair dismissal for employers with fewer than one hundred employees; reducing the power of the AIRC and giving the power to set wages to the AFPC; harmonising the industrial relations systems by bringing more businesses under the federal system; increasing the emphasis on AWAs; legislating five minimum Fair Pay and Condition Standards as the minimum for any agreement; introducing EGAs and; reducing the powers of unions. Since the changes were first announced there have been many opponents including the Labor Party, the unions and many academics. These opponents argued that the changes would reduce the wages and conditions of those most vulnerable in society including young people. Proponents of the changes argued that young people are not necessarily vulnerable when it comes to negotiating wages and conditions and that the changes would increase productivity and decrease the unemployment rate of young people. Since the legislation was enacted over a year ago there have been many changes. Wages of young people have been reduced slightly. The minimum wage...

An ergonomic evaluation of Speed Fastening work rates

Gooyers, CHAD
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 38927561 bytes; application/pdf
EN; EN
Relevância na Pesquisa
55.83%
Present day manufacturing assembly relies extensively on a variety of fasteners for the assembly of sub-systems, components and trim. Speed Fastening (SF) is one commonly used non-structural assembly fastening method. The primary limitation of SF is the lack of continuously fed rivets. One path to productivity improvement for SF is the development of a continuously feed tool that would eliminate the non-value added time currently scheduled for reloading in the work cycle. In preparation for the design of a new tool, a proactive ergonomic investigation was carried out to examine differences in muscular effort, upper-body posture, as well as subjective ratings of perceived exertion and discomfort across three different work rates for a simulated SF task conducted in a laboratory setting. The purpose of this investigation was to characterize the ergonomic consequences that an increase in work rate would have on SF operators. Twelve healthy female subjects participated in simulated SF work over four test-sessions. The first test session familiarized subjects with the SF tasks as well as the data collection protocol. Subsequent test days, which were scheduled 24 hours apart, were block randomized to one of three work rates (7, 14 and 21 fasteners/min.) with subjects required to complete 120 minutes of a simulated SF task at both waist and shoulder height using a 50% work to rest duty cycle. The results of this study show significant increases in the amount of muscular activity required to complete the simulated SF...

Evaluating outcomes of a return-to-work rehabilitation program for patients with work-related low back pain

Mngoma, Nomusa F.
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 1970553 bytes; application/pdf
EN; EN
Relevância na Pesquisa
45.65%
Purpose: The overall aim of this thesis is to contribute new knowledge by examining psychosocial factors and return-to-work profiles of occupational low back pain patients in a rehabilitation clinic. Outcome measures for injured workers with subacute low back pain included: change in measures, program utilization, pain profiles and return-to-work. Methods: A total of 147 patients who met the eligibility criteria and consented, participated in a clinic-based, individualized, exercise-based treatment that included patient education and reassurance. A before-and-after design was used, with data collection on admission to and discharge from the program. Results: Pre-to-post analyses revealed that statistically significant improvements had occurred. However, subgroup analyses revealed differences in responses to treatment among the subgroups. Specifically, two sets of cluster analyses were conducted; each yielded two distinct subgroups of patients, one set with different lengths of time in the program, and another showing two pain intensity profiles. Furthermore, return-to-work rates varied between the groups although the overall return-to-work rate appeared high. Conclusion: Significant improvement was achieved following participation in the return-to-work rehabilitation program. However...

Use of ratings of perceived exertion for predicting maximal work rate and prescribing exercise intensity in patients taking atenolol.

Eston, R G; Thompson, M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1997 EN
Relevância na Pesquisa
45.85%
OBJECTIVE: The purpose of this study was to assess the efficacy of Borg's rating of perceived exertion (RPE) scale to predict maximal exercise levels to control exercise intensity in patients taking atenolol for the treatment of essential hypertension. Normally, a standard formula (220-age) is used for calculating a percentage of exercise intensity, but beta blockade can cause reductions in maximal heart rate of between 20 and 30%. METHODS: Patients were split into a control group-10 men and 10 women, aged 50 (SD 12) and 46 (9) respectively, who had risk factors for cardiovascular disease but were not taking any drugs, and a treatment group-11 men and 11 women, aged 53 (13) and 55 (13) respectively, who were established on 25-100 mg of atenolol. All patients performed two submaximal tests on a cycle ergometer. Test 1 was an estimation test, during which the RPE was reported for each increment in work rate. Test 2 was an RPE production test, during which the patient regulated the work rate according to his/her perception of effort at four predetermined points on the RPE scale (RPE 9, 13, 15, 17). RESULTS: In both tests the individual correlations (r) between RPE, heart rate, and work rate ranged from 0.96 to 0.99. Analysis of variance showed no significant difference in maximal heart rate and maximal power output for the control group when predicted from the regression lines of RPE versus heart rate and RPE versus power output in the estimation test. However...

High strain rate constitutive modeling forhistorical structures subjected to blast loading

Rafsanjani, Seyedebrahim Hashemi
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em 07/05/2015 ENG
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Doctoral Thesis Civil Engineering; The work presented here was accomplished at the Department of Civil Engineering of University of Minho. This work involves detailed numerical studies intended to better understand the blast response of masonry structures, develops strain dependent constitutive material plasticity model for masonry, and addresses iso-damage curves for typical masonry infill walls in Portugal under blast with different loading conditions, which can be adopted for practical use in the case of enclosures. A bomb explosion near a building, in addition to a great deal of casualties and losses, can cause serious effects on the building itself, such as noticeable damage on internal and external frames, collapsing walls or shutting down of critical life safety systems. Until Oklahoma City bombing in 1995, studies dealing with the blast behavior of structures were a field of limited interest in the civil engineering community. After this terrorist attack, a great deal of effort has been done to better understand the blast response of the structures and devise solutions to reduce destructive damages and casualties due to such devastative loads. Moreover, the studies on the influence of the high strain rate on mechanical characteristics of construction materials such as steel and concrete have been carried out intensively. Unfortunately...