Within-cycle characteristics of the wheelchair push in sprinting on a wheelchair ergometer

NARCIS (Netherlands)

Veeger, DirkJan (H. E. J.); van der Woude, L H; Rozendal, R H

To investigate power output and torque production in wheelchair sprinting, six able-bodied subjects performed nine 20-s sprint tests on a stationary wheelchair ergometer (load 0-8 kg). Ergometer data were analyzed and combined with kinematic data and surface electromyography. Of all power and torque

Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling

OpenAIRE

Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

2016-01-01

[Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A T...

Development of an upwind sailing ergometer.

Science.gov (United States)

Callewaert, Margot; Geerts, Stefan; Lataire, Evert; Boone, Jan; Vantorre, Marc; Bourgois, Jan

2013-11-01

To develop a sailing ergometer that accurately simulates upwind sailing exercise. A sailing ergometer that measures roll moment accompanied by a biofeedback system that allows imposing a certain quasi-isometric upwind sailing protocol (ie, 18 bouts of 90-s hiking at constantly varying hiking intensity interspersed with 10 s to tack) was developed. Ten male high-level Laser sailors performed an incremental cycling test (ICT; ie, step protocol at 80 W + 40 W/3 min) and an upwind sailing test (UST). During both, heart rate (HR), oxygen uptake (VO(2)), ventilation (V(E)), respiratory-exchange ratio, and rating of perceived exertion were measured. During UST, also the difference between the required and produced hiking moment (HM) was calculated as error score (ES). HR, VO(2), and V(E) were calculated relative to their peak values determined during ICT. After UST, the subjects were questioned about their opinion on the resemblance between this UST and real-time upwind sailing. An average HM of 89.0% ± 2.2% HM(max) and an average ES of 4.1% ± 1.8% HM(max) were found. Mean HR, VO(2), and V(E) were, respectively, 80% ± 4% HR(peak), 39.5% ± 4.5% VO(2peak), and 30.3% ± 3.7% VE(peak). Both HM and cardiorespiratory values appear to be largely comparable to literature reports during on-water upwind sailing. Moreover, the subjects gave the upwind sailing ergometer a positive resemblance score. Results suggest that this ergometer accurately simulates on-water upwind sailing exercise. As such, this ergometer could be a great help in performance diagnostics and training follow-up.

Effect of caffeine intake on critical power model parameters determined on a cycle ergometer

Directory of Open Access Journals (Sweden)

Marcus Vinicius Machado

2010-01-01

Full Text Available The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg or placebo (maltodextrin 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively. The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p< 0.01. A high association (r2 was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively. We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

Effects of ethnicity on the relationship between vertical jump and maximal power on a cycle ergometer

Directory of Open Access Journals (Sweden)

Rouis Majdi

2016-06-01

Full Text Available The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1 than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1. Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 < ICC < 0.98 and maximal power performance (e.g. 0.75 < ICC < 0.97. However, multiple linear regression analysis showed that, for a given value of maximal power, the Afro-Caribbean participants jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

Climatic chamber ergometer

CSIR Research Space (South Africa)

Atkins, AR

1968-01-01

Full Text Available The design and calibration of an ergometer for exercising subjects during calorimetric studies in the climate chamber, are described. The ergometer is built into the climatic chamber and forms an integral part of the whole instrumentation system foe...

A BIOMECHANICAL ASSESSMENT OF ERGOMETER TASK SPECIFICITY IN ELITE FLATWATER KAYAKERS

Directory of Open Access Journals (Sweden)

Neil Fleming

2012-03-01

Full Text Available The current study compared EMG, stroke force and 2D kinematics during on-ergometer and on-water kayaking. Male elite flatwater kayakers (n = 10 performed matched exercise protocols consisting of 3 min bouts at heart and stroke rates equivalent to 85% of VO2peak (assessed by prior graded incremental test. EMG data were recorded from Anterior Deltoid (AD, Triceps Brachii (TB, Latissimus Dorsi (LD and Vastus Lateralis (VL via wireless telemetry. Video data recorded at 50 Hz with audio triggers pre- and post-exercise facilitated synchronisation of EMG and kinematic variables. Force data were recorded via strain gauge arrays on paddle and ergometer shafts. EMG data were root mean squared (20ms window, temporally and amplitude normalised, and averaged over 10 consecutive cycles. In addition, overall muscle activity was quantified via iEMG and discrete stroke force and kinematic variables computed. Significantly greater TB and LD mean iEMG activity were recorded on-water (239 ± 15 vs. 179 ± 10 µV. s, p < 0.01 and 158 ± 12 vs. 137 ± 14 µV.s, p < 0.05, respectively, while significantly greater AD activity was recorded on-ergometer (494 ± 66 vs. 340 ± 35 µV.s, p < 0.01. Time to vertical shaft position occurred significantly earlier on-ergometer (p < 0.05. Analysis of stroke force data and EMG revealed that increased AD activity was concurrent with increased external forces applied to the paddle shaft at discrete phases of the on-ergometer stroke cycle. These external forces were associated with the ergometer loading mechanism and were not observed on- water. The current results contradict a previous published hypothesis on shoulder muscle recruitment during on-water kayaking.

Potential benefits of maximal exercise just prior to return from weightlessness

Science.gov (United States)

Convertino, Victor A.

1987-01-01

The purpose of this study was to determine whether performance of a single maximal bout of exercise during weightlessness within hours of return to earth would enhance recovery of aerobic fitness and physical work capacities under a 1G environment. Ten healthy men were subjected to a 10-d bedrest period in the 6-deg headdown position. A graded maximal supine cycle ergometer test was performed before and at the end of bedrest to simulate exercise during weightlessness. Following 3 h of resumption of the upright posture, a second maximal exercise test was performed on a treadmill to measure work capacity under conditions of 1G. Compared to before bedrest, peak oxygen consumption, V(O2), decreased by 8.7 percent and peak heart rate (HR) increased by 5.6 percent in the supine cycle test at the end of bedrest. However, there were no significant changes in peak V(O2) and peak HR in the upright treadmill test following bedrest. These data suggest that one bout of maximal leg exercise prior to return from 10 d of weightlessness may be adequate to restore preflight aerobic fitness and physical work capacity.

High-Intensity Interval Exercises' Acute Impact on Heart Rate Variability: Comparison Between Whole-Body and Cycle Ergometer Protocols.

Science.gov (United States)

Schaun, Gustavo Z; Del Vecchio, Fabrício B

2018-01-01

Schaun, GZ and Del Vecchio, FB. High-intensity interval exercises' acute impact on heart rate variability: comparison between whole-body and cycle ergometer protocols. J Strength Cond Res 32(1): 223-229, 2018-Study aimed to compare the effects of 2 high-intensity interval training (HIIT) protocols on heart rate variability. Twelve young adult males (23.3 ± 3.9 years, 177.8 ± 7.4 cm, 76.9 ± 12.9 kg) volunteered to participate. In a randomized cross-over design, subjects performed 2 HIIT protocols, 1 on a cycle ergometer (Tabata protocol [TBT]; eight 20-second bouts at 170% Pmax interspersed by 10-second rest) and another with whole-body calisthenic exercises (McRae protocol; eight 20-second all-out intervals interspersed by 10-second rest). Heart rate variability outcomes in the time, frequency, and nonlinear domains were assessed on 3 moments: (a) presession; (b) immediately postsession; and (c) 24 hours postsession. Results revealed that RRmean, Ln rMSSD, Ln high frequency (HF), and Ln low frequency (LF) were significantly reduced immediately postsession (p ≤ 0.001) and returned to baseline 24 h after both protocols. In addition, LF/HF ratio was reduced 24 h postsession (p ≤ 0.01) and SD2 was significantly lower immediately postsession only in TBT. Our main finding was that responses from heart rate autonomic control were similar in both protocols, despite different modes of exercise performed. Specifically, exercises resulted in a high parasympathetic inhibition immediately after session with subsequent recovery within 1 day. These results suggest that subjects were already recovered the day after and can help coaches to better program training sessions with such protocols.

Cycle length maximization in PWRs using empirical core models

International Nuclear Information System (INIS)

Okafor, K.C.; Aldemir, T.

1987-01-01

The problem of maximizing cycle length in nuclear reactors through optimal fuel and poison management has been addressed by many investigators. An often-used neutronic modeling technique is to find correlations between the state and control variables to describe the response of the core to changes in the control variables. In this study, a set of linear correlations, generated by two-dimensional diffusion-depletion calculations, is used to find the enrichment distribution that maximizes cycle length for the initial core of a pressurized water reactor (PWR). These correlations (a) incorporate the effect of composition changes in all the control zones on a given fuel assembly and (b) are valid for a given range of control variables. The advantage of using such correlations is that the cycle length maximization problem can be reduced to a linear programming problem

Effects of Increased Respiratory Resistance on Maximal O2 Uptake and Anaerobic Threshold during Incremental Exercise Tests

OpenAIRE

ÖZÇELİK, Oğuz

2014-01-01

This study was undertaken to assess whether maximal O2 uptake (VO2max) can be used as an index of measuring aerobic capacity under the condition of increased respiratory resistance. Seven male subjects performed two incremental exercise tests on a cycle ergometer on different days: one control (C) and one breathing through an 8 mm bore diameter respiratory resistance (R). Ventilatory and gas exchange responses were measured with a turbine volume transducer and mass spectrometry, and processed...

Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness.

Science.gov (United States)

Zhang, Rubin; Zhan, Likui; Sun, Shaoming; Peng, Wei; Sun, Yining

2017-09-01

The maximum oxygen uptake (V̇O 2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to determine V̇O 2 max in young healthy male adults. Thirty-two young healthy male adults (32 males; age range: 20-35 years; height: 1.75 ± 0.05 m; weight: 67.5 ± 8.6 kg) firstly participated in a maximal-effort graded exercise test using a cycle ergometer (CE) to directly obtain measured V̇O 2 max. Subjects then completed the progressive multistage test on the RSE beginning at 50W and including additional stages of 70, 90, 110, 130, and 150W, and the RSE YMCA submaximal test consisting of a workload increase every 3 minutes until the termination criterion was reached. A metabolic equation was derived from the RSE multistage exercise test to predict oxygen consumption (V̇O 2 ) from power output (W) during the submaximal exercise test (V̇O 2 (mL·min -1 )=12.4 ×W(watts)+3.5 mL·kg -1 ·min -1 ×M+160mL·min -1 , R 2 = 0.91, standard error of the estimate (SEE) = 134.8mL·min -1 ). A high correlation was observed between the RSE YMCA estimated V̇O 2 max and the CE measured V̇O 2 max (r=0.87). The mean difference between estimated and measured V̇O 2 max was 2.5 mL·kg -1 ·min -1 , with an SEE of 3.55 mL·kg -1 ·min -1 . The data suggest that the RSE YMCA submaximal exercise test is valid for predicting V̇O 2 max in young healthy male adults. The findings show that the rectilinear stepping exercise is an effective submaximal exercise for predicting V̇O 2 max. The newly-designed RSE may be potentially further developed as an alternative ergometer for assessing

Prediction of Rowing Ergometer Performance from Functional Anaerobic Power, Strength and Anthropometric Components

Directory of Open Access Journals (Sweden)

Akça Firat

2014-07-01

Full Text Available The aim of this research was to develop different regression models to predict 2000 m rowing ergometer performance with the use of anthropometric, anaerobic and strength variables and to determine how precisely the prediction models constituted by different variables predict performance, when conducted together in the same equation or individually. 38 male collegiate rowers (20.17 ± 1.22 years participated in this study. Anthropometric, strength, 2000 m maximal rowing ergometer and rowing anaerobic power tests were applied. Multiple linear regression procedures were employed in SPSS 16 to constitute five different regression formulas using a different group of variables. The reliability of the regression models was expressed by R2 and the standard error of estimate (SEE. Relationships of all parameters with performance were investigated through Pearson correlation coefficients. The prediction model using a combination of anaerobic, strength and anthropometric variables was found to be the most reliable equation to predict 2000 m rowing ergometer performance (R2 = 0.92, SEE= 3.11 s. Besides, the equation that used rowing anaerobic and strength test results also provided a reliable prediction (R2 = 0.85, SEE= 4.27 s. As a conclusion, it seems clear that physiological determinants which are affected by anaerobic energy pathways should also get involved in the processes and models used for performance prediction and talent identification in rowing.

A systematic review and meta-analysis comparing cardiopulmonary exercise test values obtained from the arm cycle and the leg cycle respectively in healthy adults

DEFF Research Database (Denmark)

Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

2016-01-01

INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...... in studies on older and less active populations. LEVEL OF EVIDENCE: 3a....... a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. METHODS: MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across....../min with a mean ACLCratio of 0.70. The ACLCdiff was lower in studies with higher mean age and lower aerobic capacity. CONCLUSION: There is linear association between the AC and LC values in healthy adults. The AC values were on average 70% of the LC values. The magnitude of this difference appeared to be reduced...

A Systematic Review and Meta-analysis Comparing Cardiopulmonary Exercise Test Values Obtained From the Arm Cycle and the Leg Cycle Respectively in Healthy Adults

DEFF Research Database (Denmark)

Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

2016-01-01

INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...... in studies on older and less active populations. LEVEL OF EVIDENCE: 3a....... a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. METHODS: MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across....../min with a mean ACLCratio of 0.70. The ACLCdiff was lower in studies with higher mean age and lower aerobic capacity. CONCLUSION: There is linear association between the AC and LC values in healthy adults. The AC values were on average 70% of the LC values. The magnitude of this difference appeared to be reduced...

Limitations of Spectral Electromyogramic Analysis to Determine the Onset of Neuromuscular Fatigue Threshold during Incremental Ergometer Cycling

Directory of Open Access Journals (Sweden)

Iban Latasa, Alfredo Cordova, Armando Malanda, Javier Navallas, Ana Lavilla-Oiz, Javier Rodriguez-Falces

2016-03-01

Full Text Available Recently, a new method has been proposed to detect the onset of neuromuscular fatigue during an incremental cycling test by assessing the changes in spectral electromyographic (sEMG frequencies within individual exercise periods of the test. The method consists on determining the highest power output that can be sustained without a significant decrease in spectral frequencies. This study evaluated the validity of the new approach by assessing the changes in spectral indicators both throughout the whole test and within individual exercise periods of the test. Fourteen cyclists performed incremental cycle ergometer rides to exhaustion with bipolar surface EMG signals recorded from the vastus lateralis. The mean and median frequencies (Fmean and Fmedian, respectively of the sEMG power spectrum were calculated. The main findings were: (1 Examination of spectral indicators within individual exercise periods of the test showed that neither Fmean nor Fmedian decreased significantly during the last (most fatiguing exercise periods. (2 Examination of the whole incremental test showed that the behaviour of Fmean and Fmedian with increasing power output was highly inconsistent and varied greatly among subjects. (3 Over the whole incremental test, half of the participants exhibited a positive relation between spectral indicators and workload, whereas the other half demonstrated the opposite behavior. Collectively, these findings indicate that spectral sEMG indexes do not provide a reliable measure of the fatigue state of the muscle during an incremental cycling test. Moreover, it is concluded that it is not possible to determine the onset of neuromuscular fatigue during an incremental cycling test by examining spectral indicators within individual exercise periods of the test.

CHANGES IN EEG DURING GRADED EXERCISE ON A RECUMBENT CYCLE ERGOMETER

Directory of Open Access Journals (Sweden)

Stephen P. Bailey

2008-12-01

Full Text Available Previous studies have shown changes in brain activity as a result of exercise; however, few studies have examined changes during exercise. The purpose of this study was to examine brain activity during a graded exercise test. Twenty male participants performed a graded exercise test on a recumbent cycle ergometer. Exercise intensity was set initially at 50W and was increased by 50W every 2 minutes until volitional fatigue was reached. Electroencephalography (EEG was measured prior to the onset of exercise, during the last minute of each stage of exercise, immediately post-exercise, and 10 minutes into recovery. EEG was recorded from 8 scalp sites leading to analysis of alpha 1, alpha 2, beta 1, beta 2, and theta activities. Expired air was collected and analyzed for ventilation rate (VE, VO2, % of peak VO2, and Respiratory Exchange Ratio (RER. No differences were seen in EEG between the hemispheres of the brain. There was, however, a significant increase in brain activity across the spectrum occurring at 200 W through immediately post-exercise. Brain activity returned to pre- exercise levels by 10 minutes post. VO2, % of peak VO2 and RER increased linearly with exercise intensity. VE increased linearly through 200 W; however, a disproportionate increase was seen in VE from 200 W to peak exercise. The results of this investigation demonstrate that brain activity may be related to exercise intensity. Future research will want to examine how these changes in brain activity influence affective, perceptual and cognitive changes often associated with exercise. Efforts will also need to be made to determine if changes in brain activity during exercise are mediated by central (within the brain or peripheral mechanisms

Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness

OpenAIRE

Rubin Zhang, Likui Zhan, Shaoming Sun, Wei Peng, Yining Sun

2017-01-01

The maximum oxygen uptake (V̇O2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to det...

Effect of formoterol, a long-acting β2-adrenergic agonist, on muscle strength and power output, metabolism and fatigue during maximal sprinting in men

DEFF Research Database (Denmark)

Kalsen, Anders; Hostrup, Morten; Backer, Vibeke

2016-01-01

The aim was to investigate the effect of the long-acting β2-adrenergic agonist formoterol on muscle strength and power output, muscle metabolism and phosphorylation of CaMKII Thr(287) and FXYD1 during maximal sprinting. In a double-blind crossover study, thirteen males (VO2max: 45.0±0.2 (mean±SE) m......L min(-1) kg(-1)) performed a 30-s cycle ergometer sprint after inhalation of either 54 µg formoterol (FOR) or placebo (PLA). Before and after the sprint, muscle biopsies were collected from vastus lateralis and maximal voluntary contraction (MVC) and contractile properties of quadriceps were measured...

Fatigue during maximal sprint cycling: unique role of cumulative contraction cycles.

Science.gov (United States)

Tomas, Aleksandar; Ross, Emma Z; Martin, James C

2010-07-01

Maximal cycling power has been reported to decrease more rapidly when performed with increased pedaling rates. Increasing pedaling rate imposes two constraints on the neuromuscular system: 1) decreased time for muscle excitation and relaxation and 2) increased muscle shortening velocity. Using two crank lengths allows the effects of time and shortening velocity to be evaluated separately. We conducted this investigation to determine whether the time available for excitation and relaxation or the muscle shortening velocity was mainly responsible for the increased rate of fatigue previously observed with increased pedaling rates and to evaluate the influence of other possible fatiguing constraints. Seven trained cyclists performed 30-s maximal isokinetic cycling trials using two crank lengths: 120 and 220 mm. Pedaling rate was optimized for maximum power for each crank length: 135 rpm for the 120-mm cranks (1.7 m x s(-1) pedal speed) and 109 rpm for the 220-mm cranks (2.5 m x s(-1) pedal speed). Power was recorded with an SRM power meter. Crank length did not affect peak power: 999 +/- 276 W for the 120-mm crank versus 1001 +/- 289 W for the 220-mm crank. Fatigue index was greater (58.6% +/- 3.7% vs 52.4% +/- 4.8%, P < 0.01), and total work was less (20.0 +/- 1.8 vs 21.4 +/- 2.0 kJ, P < 0.01) with the higher pedaling rate-shorter crank condition. Regression analyses indicated that the power for the two conditions was most highly related to cumulative work (r2 = 0.94) and to cumulative cycles (r2 = 0.99). These results support previous findings and confirm that pedaling rate, rather than pedal speed, was the main factor influencing fatigue. Our novel result was that power decreased by a similar increment with each crank revolution for the two conditions, indicating that each maximal muscular contraction induced a similar amount of fatigue.

Slide-based ergometer rowing

DEFF Research Database (Denmark)

Vinther, Anders; Alkjær, T; Kanstrup, I-L

2012-01-01

Force production profile and neuromuscular activity during slide-based and stationary ergometer rowing at standardized submaximal power output were compared in 14 male and 8 female National Team rowers. Surface electromyography (EMG) was obtained in selected thoracic and leg muscles along with sy...

Associations of maximal strength and muscular endurance test scores with cardiorespiratory fitness and body composition.

Science.gov (United States)

Vaara, Jani P; Kyröläinen, Heikki; Niemi, Jaakko; Ohrankämmen, Olli; Häkkinen, Arja; Kocay, Sheila; Häkkinen, Keijo

2012-08-01

The purpose of the present study was to assess the relationships between maximal strength and muscular endurance test scores additionally to previously widely studied measures of body composition and maximal aerobic capacity. 846 young men (25.5 ± 5.0 yrs) participated in the study. Maximal strength was measured using isometric bench press, leg extension and grip strength. Muscular endurance tests consisted of push-ups, sit-ups and repeated squats. An indirect graded cycle ergometer test was used to estimate maximal aerobic capacity (V(O2)max). Body composition was determined with bioelectrical impedance. Moreover, waist circumference (WC) and height were measured and body mass index (BMI) calculated. Maximal bench press was positively correlated with push-ups (r = 0.61, p strength (r = 0.34, p strength correlated positively (r = 0.36-0.44, p test scores were related to maximal aerobic capacity and body fat content, while fat free mass was associated with maximal strength test scores and thus is a major determinant for maximal strength. A contributive role of maximal strength to muscular endurance tests could be identified for the upper, but not the lower extremities. These findings suggest that push-up test is not only indicative of body fat content and maximal aerobic capacity but also maximal strength of upper body, whereas repeated squat test is mainly indicative of body fat content and maximal aerobic capacity, but not maximal strength of lower extremities.

Automatic optimization of core loading patterns to maximize cycle energy production within operational constraints

International Nuclear Information System (INIS)

Hobson, G.H.; Turinsky, P.J.

1986-01-01

Computational capability has been developed to automatically determine the core loading pattern which minimizes fuel cycle costs for a pressurized water reactor. Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern which maximizes core reactivity at end-of-cycle while satisfying the power peaking constraint throughout the cycle and region average discharge burnup limit. The method utilizes a two-dimensional, coarse mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern as a function of cycle burnup. First order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, and end-of-cycle burnup

Bicarbonate attenuates arterial desaturation during maximal exercise in humans

DEFF Research Database (Denmark)

Nielsen, Henning B; Bredmose, Per P; Strømstad, Morten

2002-01-01

The contribution of pH to exercise-induced arterial O2 desaturation was evaluated by intravenous infusion of sodium bicarbonate (Bic, 1 M; 200-350 ml) or an equal volume of saline (Sal; 1 M) at a constant infusion rate during a "2,000-m" maximal ergometer row in five male oarsmen. Blood...

Changes in EEG during graded exercise on a recumbent cycle ergometer.

Science.gov (United States)

Bailey, Stephen P; Hall, Eric E; Folger, Stephen E; Miller, Paul C

2008-01-01

Previous studies have shown changes in brain activity as a result of exercise; however, few studies have examined changes during exercise. The purpose of this study was to examine brain activity during a graded exercise test. Twenty male participants performed a graded exercise test on a recumbent cycle ergometer. Exercise intensity was set initially at 50W and was increased by 50W every 2 minutes until volitional fatigue was reached. Electroencephalography (EEG) was measured prior to the onset of exercise, during the last minute of each stage of exercise, immediately post-exercise, and 10 minutes into recovery. EEG was recorded from 8 scalp sites leading to analysis of alpha 1, alpha 2, beta 1, beta 2, and theta activities. Expired air was collected and analyzed for ventilation rate (VE), VO2, % of peak VO2, and Respiratory Exchange Ratio (RER). No differences were seen in EEG between the hemispheres of the brain. There was, however, a significant increase in brain activity across the spectrum occurring at 200 W through immediately post-exercise. Brain activity returned to pre- exercise levels by 10 minutes post. VO2, % of peak VO2 and RER increased linearly with exercise intensity. VE increased linearly through 200 W; however, a disproportionate increase was seen in VE from 200 W to peak exercise. The results of this investigation demonstrate that brain activity may be related to exercise intensity. Future research will want to examine how these changes in brain activity influence affective, perceptual and cognitive changes often associated with exercise. Efforts will also need to be made to determine if changes in brain activity during exercise are mediated by central (within the brain) or peripheral mechanisms. Key pointsEEG can be recorded during exercise.Brain EEG activity increases during exercise and may be related to exercise intensity.Brain EEG activity returns to resting levels quickly after the cessation of exercise.

Neuromuscular adjustments of the quadriceps muscle after repeated cycling sprints.

Directory of Open Access Journals (Sweden)

Olivier Girard

Full Text Available PURPOSE: This study investigated the supraspinal processes of fatigue of the quadriceps muscle in response to repeated cycling sprints. METHODS: Twelve active individuals performed 10 × 6-s "all-out" sprints on a cycle ergometer (recovery = 30 s, followed 6 min later by 5 × 6-s sprints (recovery = 30 s. Transcranial magnetic and electrical femoral nerve stimulations during brief (5-s and sustained (30-s isometric contractions of the knee extensors were performed before and 3 min post-exercise. RESULTS: Maximal strength of the knee extensors decreased during brief and sustained contractions (~11% and 9%, respectively; P0.05. While cortical voluntary activation declined (P 40% reduced (P<0.001 following exercise. CONCLUSION: The capacity of the motor cortex to optimally drive the knee extensors following a repeated-sprint test was shown in sustained, but not brief, maximal isometric contractions. Additionally, peripheral factors were largely involved in the exercise-induced impairment in neuromuscular function, while corticospinal excitability was well-preserved.

Effect of BMI on Knee Joint Torques in Ergometer Rowing

NARCIS (Netherlands)

Roemer, Karen; Hortobagyi, Tibor; Richter, Chris; Munoz-Maldonado, Yolanda; Hamilton, Stephanie

2013-01-01

Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity

Validity and Reliability of the Cycleops Hammer Cycle Ergometer.

Science.gov (United States)

Lillo-Bevia, José R; Pallarés, Jesús G

2017-11-28

To validate the new drive indoor trainer Hammer designed by Cycleops®. Eleven cyclists performed 44 randomized and counterbalanced graded exercise tests (100-500W), at 70, 85 and 100 rev.min -1 cadences, in seated and standing positions, on 3 different Hammer units, while a scientific SRM system continuously recorded cadence and power output data. No significant differences were detected between the three Hammer devices and the SRM for any workload, cadence, or pedalling condition (P value between 1.00 and 0.350), except for some minor differences (P 0.03 and 0.04) found in the Hammer 1 at low workloads, and for Hammer 2 and 3 at high workloads, all in seated position. Strong ICCs were found between the power output values recorded by the Hammers and the SRM (≥0.996; P=0.001), independently from the cadence condition and seated position. Bland-Altman analysis revealed low Bias (-5.5-3.8) and low SD of Bias (2.5-5.3) for all testing conditions, except marginal values found for the Hammer 1 at high cadences and seated position (9.6±6.6). High absolute reliability values were detected for the 3 Hammers (150-500W; CVreliable device to drive and measure power output in cyclists, providing an alternative to larger and more expensive laboratory ergometers, and allowing cyclists to use their own bicycle.

Efeito de oito semanas de suplementação com creatina monoidratada sobre o trabalho total relativo em esforços intermitentes máximos no cicloergômetro de homens treinados Effect of eight weeks of creatine supplementation on relative total work in intermittent maximal efforts in the cycle ergometer of trained men

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Leandro Ricardo Altimari

2006-06-01

Full Text Available Este estudo investigou o efeito de um longo período de suplementação com creatina monoidratada (Cr m sobre o trabalho total relativo (TTR em esforços intermitentes máximos no cicloergômetro de homens treinados. Vinte seis indivíduos foram divididos aleatoriamente em grupo creatina (CR, n=13 e grupo placebo (PL, n=13. Os sujeitos receberam em sistema duplo-cego, doses de Cr m ou placebo-maltodextrina (20 g.d-1 por 5 dias e 3 g.d-1 durante 51 dias subseqüentes. Os grupos tiveram seus hábitos alimentares e sua condição física previamente controlados. Para determinação do TTR os sujeitos foram submetidos a protocolo de exercício em cicloergômetro composto de três Testes de Wingate de 30s separados por dois minutos recuperação, antes e após o período de suplementação. ANOVA, seguido pelo teste post hoc de Tukey, quando pThis study investigated the effect of long-term supplementation with creatine monohydrate (Cr m on relative total work (RTW in intermittent maximal efforts in the cycle ergometer of trained men. Twenty six individuals were randomly divided in creatine group (CR, n=13 and placebo group (PL, n=13. The subjects received in a double-blind manner, doses of Cr m or placebo-maltodextrin (20 g.d-1 for 5 days and 3 g.d-1 for 51 subsequent days. The groups had their alimentary habits and physical fitness controlled previously. For determination of the RTW the subjects were submitted to exercise protocol in cycle ergometer comprised three 30s Anaerobic Wingate Test interspersed with two minutes recovery, before and after the supplementation period. ANOVA, followed by the Tukey post hoc test, when p<0.05, were used for data treatment. There was a significant time effect for RTW (F1,24=8.00; p<0.05, with the CR group demonstrating significant greater (3% on the RTW production compared to PL group after the supplementation period (690.54 ± 46.83 vs 655.71 ± 74.34 J.kg-1 respectively; p<0.05. The results of the present study

COMPARISON OF ROWING ON A CONCEPT 2 STATIONARY AND DYNAMIC ERGOMETER

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Aaron Benson

2011-06-01

Full Text Available Biomechanical and physiological responses to rowing 1000 m at a power output equivalent to a 2000 m race were compared in 34 collegiate rowers (17 women, 17 men rowing on a stationary and dynamic Concept 2 ergometer. Stroke ratio, peak handle force, rate of force development, impulse, and respiratory exchange ratio decreased by 15.7, 14.8, 10.9, 10.2 and 1.9%, respectively, on the dynamic ergometer. In contrast, percent time to peak force and stroke rate increased by 10.5 and 12.6%, respectively, during dynamic ergometry; the changes in stroke rate and impulse were greater for men than women. Last, VO2 was 5.1% higher and efficiency 5. 3% lower on the dynamic ergometer for men. Collegiate rowers used higher stoke rates and lower peak stroke forces to achieve a similar power output while rowing at race pace on the dynamic ergometer, which may have increased the cardiopulmonary demand and possibly reduced force production in the primary movers. Differences were more pronounced in males than females; this dichotomy may be more due to dynamic ergometer familiarity than sex

Effect of caffeine intake on critical power model parameters determined on a cycle ergometer DOI:10.5007/1980-0037.2010v12n1p49

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Marcus Vinicius Machado

2010-12-01

Full Text Available The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg or placebo (maltodextrin 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively. The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p< 0.01. A high association (r2 was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively. We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

Comparação entre a utilização de saliva e sangue para determinação do lactato mínimo em cicloergômetro e ergômetro de braço em mesa-tenistas Comparacion entre la utilizacion de saliva y sangre para la determinacion del lactato mínimo en cicloergómetro y ergómetro de brazo en tenistas de mesa Comparison between the use of saliva and blood for the minimum lactate determination in arm ergometer and cycle ergometer in table tennis players

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Alessandro Moura Zagatto

2004-12-01

al test de correlación de Pearson con niveles de significancia de 5%. Los LACmin determinados con muestras de sangre y de saliva tanto para el ergômetro de brazo (LACmin brazo 91,71 ± 12,43; Na+min brazo-saliva 71,99 ± 23,42; K+min brazo-saliva 79,67 ± 17,72, como para el cicloergómetro (LACmin ciclo 157,68 ± 13,48; LACmin ciclo-saliva 135,49 ± 33,2; Na+min ciclo-saliva 121,81 ± 51,31; K+min ciclo-saliva 135,49 ± 33,21 no fueron diferentes significativamente. Con todo, estas intensidades no presentaron correlaciones significativas. Se puede entónces concluir que la utilización de los metabólitos en la saliva para la determinación de la del TLM no parece ser posible para este protocolo cuando los ergómetros utilizados son el ergómetro de brazo isocinético y el cicloergómetro.The aim of this study was to verify if it is possible to determine the lactate minimum test (LMT by saliva sodium (Na+, potassium (K+ and lactate (LAC concentrations in arm ergometer and cycle ergometers. Eight male international-level table tennis players participated in this study. To induce increases of lactate concentration in both ergometers, 30 seconds maximal tests were used with maximal force application in constant 102 rpm in isokinetic arm ergometer (Cybex UBE 2432, and loads of 7.5% of body weight (Kp in cycle ergometer (mechanical Monark. After the anaerobic stimulus in arm ergometer, the incremental test was applied at constant 60 rpm, started at 49 watts and increment loads of 16 watts each three minutes. The LMT intensity was determined with the analysis of the blood lactate (LACmin arm and the saliva concentrations of sodium (Na+min arm-saliva and potassium (K+min arm-saliva. For the cycle ergometer, the incremental test started with an intensity of 85 watts and increments of 17 watts at constant speed of 70 rpm. The stages were also of three minutes. The LACmin was determined using blood and saliva samples (LACmin cycle; Na+min cycle-saliva, K+min cycle

Validity And Reliability Of The Stages Cycling Power Meter.

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Granier, Cyril; Hausswirth, Christophe; Dorel, Sylvain; Yann, Le Meur

2017-09-06

This study aimed to determine the validity and the reliability of the Stages power meter crank system (Boulder, United States) during several laboratory cycling tasks. Eleven trained participants completed laboratory cycling trials on an indoor cycle fitted with SRM Professional and Stages systems. The trials consisted of an incremental test at 100W, 200W, 300W, 400W and four 7s sprints. The level of pedaling asymmetry was determined for each cycling intensity during a similar protocol completed on a Lode Excalibur Sport ergometer. The reliability of Stages and SRM power meters was compared by repeating the incremental test during a test-retest protocol on a Cyclus 2 ergometer. Over power ranges of 100-1250W the Stages system produced trivial to small differences compared to the SRM (standardized typical error values of 0.06, 0.24 and 0.08 for the incremental, sprint and combined trials, respectively). A large correlation was reported between the difference in power output (PO) between the two systems and the level of pedaling asymmetry (r=0.58, p system according to the level of pedaling asymmetry provided only marginal improvements in PO measures. The reliability of the Stages power meter at the sub-maximal intensities was similar to the SRM Professional model (coefficient of variation: 2.1 and 1.3% for Stages and SRM, respectively). The Stages system is a suitable device for PO measurements, except when a typical error of measurement power ranges of 100-1250W is expected.

Crossover and maximal fat-oxidation points in sedentary healthy subjects: methodological issues.

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Gmada, N; Marzouki, H; Haboubi, M; Tabka, Z; Shephard, R J; Bouhlel, E

2012-02-01

Our study aimed to assess the influence of protocol on the crossover point and maximal fat-oxidation (LIPOX(max)) values in sedentary, but otherwise healthy, young men. Maximal oxygen intake was assessed in 23 subjects, using a progressive maximal cycle ergometer test. Twelve sedentary males (aged 20.5±1.0 years) whose directly measured maximal aerobic power (MAP) values were lower than their theoretical maximal values (tMAP) were selected from this group. These individuals performed, in random sequence, three submaximal graded exercise tests, separated by three-day intervals; work rates were based on the tMAP in one test and on MAP in the remaining two. The third test was used to assess the reliability of data. Heart rate, respiratory parameters, blood lactate, the crossover point and LIPOX(max) values were measured during each of these tests. The crossover point and LIPOX(max) values were significantly lower when the testing protocol was based on tMAP rather than on MAP (PtMAP at 30, 40, 50 and 60% of maximal aerobic power (PtMAP rather than MAP (P<0.001). During the first 5 min of recovery, EPOC(5 min) and blood lactate were significantly correlated (r=0.89; P<0.001). Our data show that, to assess the crossover point and LIPOX(max) values for research purposes, the protocol must be based on the measured MAP rather than on a theoretical value. Such a determination should improve individualization of training for initially sedentary subjects. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

The influence of evaluation protocol on time spent exercising at a high level of oxygen uptake during continuous cycling.

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Merry, K L; Glaister, M; Howatson, G; Van Someren, K

2015-10-01

This study evaluated the effects of protocol variation on the time spent exercising at ≥95% V̇O2max during cycle ergometer trials performed at the exercise intensity associated with V̇O2max (iV̇O2max). Nine male triathletes (age: 32±10 years; body mass: 73.3±6.1 kg; stature: 1.79±0.07 m; V̇O2max: 3.58±0.45 L.min(-1)) performed four exercise tests. During tests 1 and 2, participants performed a maximal incremental cycle ergometer test using different stage durations (1 min and 3 min) for the determination of iV̇O2max (1 min) and iV̇O2max (3 min). During tests 3 and 4, participants performed a continuous bout of exhaustive cycling at iV̇O2max (1 min) (CONT1) and iV̇O2max (3 min) (CONT3). iV̇O2max (1 min) was significantly greater (Pexercising continuously at iV̇O2max, time spent at ≥95% V̇O2max is influenced by the initial measurement of iV̇O2max.

Gross efficiency and energy expenditure in kayak ergometer exercise.

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Gomes, B B; Mourão, L; Massart, A; Figueiredo, P; Vilas-Boas, J P; Santos, A M C; Fernandes, R J

2012-08-01

We purposed to study energy expenditure, power output and gross efficiency during kayak ergometer exercise in 12 elite sprint kayakers. 6 males (age 24.2±4.8 years, height 180.4±4.8 cm, body mass 79.7±8.5 kg) and 6 females (age 24.3±4.5 years, height 164.5±3.9 cm, body mass 65.4±3.5 kg), performed an incremental intermittent protocol on kayak ergometer with VO2 and blood lactate concentration assessment, a non-linear increase between power output and energy expenditure being observed. Paddling power output, energy expenditure and gross efficiency corresponding to VO2max averaged 199.92±50.41 W, 75.27±6.30 ml.kg - 1.min - 1, and 10.10±1.08%. Male kayakers presented higher VO2max, power output and gross efficiency at the VO2max, and lower heart rate and maximal lactate concentration than females, but no differences were found between genders regarding energy expenditure at VO2max. Aerobic and anaerobic components of energy expenditure evidenced a significant contribution of anaerobic energy sources in sprint kayak performance. Results also suggested the dependence of the gross efficiency on the changes in the amount of the aerobic and anaerobic contributions, at heavy and severe intensities. The inter-individual variance of the relationship between energy expenditure and the corresponding paddling power output revealed a relevant tracking for females (FDγ=0.73±0.06), conversely to the male group (FDγ=0.27±0.08), supporting that some male kayakers are more skilled in some paddling intensities than others. © Georg Thieme Verlag KG Stuttgart · New York.

Cardiorespiratory and metabolic responses during straight and bent knee cycling.

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Mandroukas, K; Angelopoulou, N; Christoulas, K; Vrabas, I S

2000-06-01

This study examined the influence of knee angle on the cardiorespiratory system loading during submaximal and maximal stationary cycle ergometry. Experimental design and participants: eighteen untrained women (age: 21+/-1.88 years, weight: 57+/-5.75 kg, height: 165+/-5.03 cm, values are mean+/-SD) volunteered as subjects and underwent two-cycle ergometer incremental (Jaeger ER900) tests: 1) straight knee (180 degrees), 2) bent knee (140 degrees). oxygen uptake (VO2), ventilation (VE) and respiratory exchange ratio (RER) were measured continuously during each test using an open circuit spirometry and blood lactate concentration was determined by means of an enzymatic method. Comparing cycling with "straight knee" to cycling with "bent knee" at 50 W, heart rate (HR), V(E) and VO2 were significantly higher (10.6%, 12.5%, 17.8%). At 100 W, blood lactate was significantly lower (10.8%) while VO2 and RER was higher (5.5%, 7.1%). During maximal exercise, the total exercise time was significantly longer (11.2%) and VE, VO2 and HR were significantly higher during cycling with "straight knee" compared to cycling with "bent knee". No significant difference in peak lactate was evident between the two sitting positions. The results of this study indicate that cycling with bent knee requires lower oxygen uptake while pedaling with straight knee is the only way to reach VO2max during cycle testing, since the cardiorespiratory system is fully taxed.

Laboratory and Field-Based Evaluation of Short-Term Effort with Maximal Intensity in Individuals with Intellectual Disabilities

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Lencse-Mucha Judit

2015-12-01

Full Text Available Results of previous studies have not indicated clearly which tests should be used to assess short-term efforts of people with intellectual disabilities. Thus, the aim of the present study was to evaluate laboratory and field-based tests of short-term effort with maximal intensity of subjects with intellectual disabilities. Twenty four people with intellectual disability, who trained soccer, participated in this study. The 30 s Wingate test and additionally an 8 s test with maximum intensity were performed on a bicycle ergometer. The fatigue index, maximal and mean power, relative maximal and relative mean power were measured. Overall, nine field-based tests were conducted: 5, 10 and 20 m sprints, a 20 m shuttle run, a seated medicine ball throw, a bent arm hang test, a standing broad jump, sit-ups and a hand grip test. The reliability of the 30 s and 8 s Wingate tests for subjects with intellectual disability was confirmed. Significant correlation was observed for mean power between the 30 s and 8 s tests on the bicycle ergometer at a moderate level (r >0.4. Moreover, significant correlations were indicated between the results of laboratory tests and field tests, such as the 20 m sprint, the 20 m shuttle run, the standing long jump and the medicine ball throw. The strongest correlation was in the medicine ball throw. The 30 s Wingate test is a reliable test assessing maximal effort in subjects with intellectual disability. The results of this research confirmed that the 8 s test on a bicycle ergometer had a moderate correlation with the 30 s Wingate test in this population, thus, this comparison needs further investigation to examine alternativeness of the 8 s to 30 s Wingate tests. The non-laboratory tests could be used to indirectly assess performance in short-term efforts with maximal intensity.

Laboratory and Field-Based Evaluation of Short-Term Effort with Maximal Intensity in Individuals with Intellectual Disabilities

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Lencse-Mucha, Judit; Molik, Bartosz; Marszałek, Jolanta; Kaźmierska-Kowalewska, Kalina; Ogonowska-Słodownik, Anna

2015-01-01

Results of previous studies have not indicated clearly which tests should be used to assess short-term efforts of people with intellectual disabilities. Thus, the aim of the present study was to evaluate laboratory and field-based tests of short-term effort with maximal intensity of subjects with intellectual disabilities. Twenty four people with intellectual disability, who trained soccer, participated in this study. The 30 s Wingate test and additionally an 8 s test with maximum intensity were performed on a bicycle ergometer. The fatigue index, maximal and mean power, relative maximal and relative mean power were measured. Overall, nine field-based tests were conducted: 5, 10 and 20 m sprints, a 20 m shuttle run, a seated medicine ball throw, a bent arm hang test, a standing broad jump, sit-ups and a hand grip test. The reliability of the 30 s and 8 s Wingate tests for subjects with intellectual disability was confirmed. Significant correlation was observed for mean power between the 30 s and 8 s tests on the bicycle ergometer at a moderate level (r >0.4). Moreover, significant correlations were indicated between the results of laboratory tests and field tests, such as the 20 m sprint, the 20 m shuttle run, the standing long jump and the medicine ball throw. The strongest correlation was in the medicine ball throw. The 30 s Wingate test is a reliable test assessing maximal effort in subjects with intellectual disability. The results of this research confirmed that the 8 s test on a bicycle ergometer had a moderate correlation with the 30 s Wingate test in this population, thus, this comparison needs further investigation to examine alternativeness of the 8 s to 30 s Wingate tests. The non-laboratory tests could be used to indirectly assess performance in short-term efforts with maximal intensity. PMID:26834874

Phlebotomy eliminates the maximal cardiac output response to six weeks of exercise training

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Bonne, Thomas Christian; Doucende, Gregory; Flück, Daniela

2014-01-01

With this study we tested the hypothesis that six weeks of endurance training increases maximal cardiac output (Qmax) relatively more by elevating blood volume (BV) than by inducing structural and functional changes within the heart. Nine healthy but untrained volunteers (VO2max 47 ± 5 ml.min(-1......).kg(-1)) underwent supervised training (60 min; 4 times weekly at 65% VO2max for six weeks) and Qmax was determined by inert gas re-breathing during cycle ergometer exercise before and after the training period. After the training period, blood volume (determined in duplicates by CO re......-breathing) was re-established to pre-training values by phlebotomy and Qmax was quantified again. Resting echography revealed no structural heart adaptations as a consequence of the training intervention. Following the training period, plasma volume (PV), red blood cell volume (RBCV) and BV increased (p...

Physical exercises on a bicycle-ergometer and running track to prevent hypodynamia in workers of intellectual labor

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Vasilyeva, V. V.; Korableva, Y. N.; Trunin, V. V.

1980-01-01

A program of exercises was developed and tested, consisting of a 12 minute session on a variable load bicycle ergometer and a 10-11 min. run with brief stretching and resting sessions between. Physical performance capacity was measured before, during, and after the period of the experiment and physical exams conducted. After a 4 month test period involving 30 men, aged 25-35, the program was found to be successful in increasing physical performance capacity. The PWC170 increased an average of 22 percent and maximum oxygen consumption 14 percent. Arterial pressure dropped (120/75 to 114/68), vital capacity of lungs increased by 6 percent, strength of respiratory muscles by 8.8 percent, duration of respiratory delay by 18 percent. Duration of cardiac cycles increased, stress index decreased. Cardiac contraction rate 2 minutes after work on the ergometer decreased from 118 to 102 bt/min.

Effects of combined high intensity arm and leg training on performance and cardio-respiratory measures.

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Zinner, Christoph; Sperlich, Billy; Born, Dennis-Peter; Michels, Guido

2017-01-01

The purpose of this study was to investigate the effects of combined arm and leg high-intensity low-volume interval training (HIITarm+leg) on maximal oxygen uptake, myocardial measures (i.e. stroke volume, cardiac output, ejection fraction), Tissue Oxygenation Index (TOI) of the vastus lateralis and triceps brachii, as well as power output in comparison to leg HIIT (HIITleg) only. The 20 healthy, male and female volunteers completed six sessions of either HIITleg on a cycle ergometer or HIITarm+leg on an arm and leg cycle ergometer. During pre- and post-testing, the volunteers completed a submaximal and incremental test to exhaustion on a cycle ergometer. Magnitude based interference revealed likely to very likely beneficial effects for HIITarm+leg compared to HIITleg in maximal oxygen uptake, cardiac measures as well peak power output. The TOI following HIITarm+leg demonstrated likely to very likely increased oxygenation in the triceps brachii or the vastus lateralis when compared to HIITleg. The results suggest that six sessions of HIITarm+leg may likely to very likely improve maximal oxygen uptake, some inotropy-related cardiac measures with improved tissue oxygenation of the triceps brachii and vastus lateralis muscles resulting in greater leg peak power output.

External And Internal Work Of A T-6 Paraplegic Propelling A Wheelchair And Arm Cranking A Cycle Ergometer: Case Study

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Novak, Charles W.

1982-02-01

In this, the International Year of the Disabled, attention is directed among other areas toward rehabilitation and sports participation of wheelchair users. As an application of movement analysis in medicine and rehabilitation and as an application of sports research using biomechanics, this investigation was performed to compare the results of two methods of gathering data on the stress of wheelchair propelling at equivalent work loads and to account for differences in physiological responses with a mechanical analysis of wheelchair propelling. Physiological data collected were heart rate, systolic blood pressure, and rate-pressure product. A biomechanical cinematography analysis was used to determine external work in wheelchair propelling and to determine the extent to which modifications in segment actionsoccurred during increasing magnitude of work. A cycle ergometer was adjusted to replicate external work loads performed during wheelchair propelling. A t-test of equivalent external work loads indicated that heart rate was not different between the two exercise modes at the .05 level of significance. The t-test did indicate a significant difference in systolic blood pressure and rate-pressure product at the .05 level of significance. The biomechanical analysis of wheelchair propelling established that an increase in external work was accomplished by a decrease in the range of motion and an increase in the speed of movement. During cycle ergometry the range and speed of movement remained the same while resistance was increased. Results of the study established that while heart rate for equivalent external work loads was the same for wheelchair propelling and arm cranking cycle ergometry, systolic blood pressure and rate-pressure product were not the same. The suggestion was that some means of propelling a wheelchair other than that which is con-sidered "standard" might be considered which produces less stressful responses in wheelchair users.

Maximal fat oxidation rates in endurance trained and untrained women

DEFF Research Database (Denmark)

Stisen, A.B.; Stougaard, O.; Langfort, J.

2006-01-01

The aim of the present study was to examine the differences in fat oxidation between endurance trained (ET) and untrained (UT) women. Eight ET and nine UT women performed a progressive cycle ergometer test until exhaustion. The rate of fat oxidation was similar at low work rates (...

Effect of Locomotor Respiratory Coupling Induced by Cortical Oxygenated Hemoglobin Levels During Cycle Ergometer Exercise of Light Intensity.

Science.gov (United States)

Oyanagi, Keiichi; Tsubaki, Atsuhiro; Yasufuku, Yuichi; Takai, Haruna; Kera, Takeshi; Tamaki, Akira; Iwata, Kentaro; Onishi, Hideaki

This study aimed to clarify the effects of locomotor-respiratory coupling (LRC) induced by light load cycle ergometer exercise on oxygenated hemoglobin (O2Hb) in the dorsolateral prefrontal cortex (DLPFC), supplementary motor area (SMA), and sensorimotor cortex (SMC). The participants were 15 young healthy adults (9 men and 6 women, mean age: 23.1 ± 1.8 (SEM) years). We conducted a task in both LRC-inducing and LRC-non-inducing conditions for all participants. O2Hb was measured using near-infrared spectroscopy. The LRC frequency ratio during induction was 2:1; pedaling rate, 50 rpm; and intensity of load, 30 % peak volume of oxygen uptake. The test protocol included a 3-min rest prior to exercise, steady loading motion for 10 min, and 10-min rest post exercise (a total of 23 min). In the measurement of O2Hb, we focused on the DLPFC, SMA, and SMC. The LRC frequency was significantly higher in the LRC-inducing condition (p < 0.05). O2Hb during exercise was significantly lower in the DLPFC and SMA, under the LRC-inducing condition (p < 0.05). The study revealed that even light load could induce LRC and that O2Hb in the DLPFC and SMA decreases during exercise via LRC induction.

VARIATION IN RESISTIVE FORCE SELECTION DURING BRIEF HIGH INTENSITY CYCLE ERGOMETRY: IMPLICATIONS FOR POWER ASSESSMENT AND PRODUCTION IN ELITE KARATE PRACTITIONERS

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Julien Steven Baker

2006-07-01

Full Text Available The purpose of this study was to measure power values generated in elite karate fighters during brief high intensity cycle ergometry when resistive forces were derived from total - body mass (TBM or fat - free mass (FFM. Male international karate practitioners volunteered as participants (n = 11. Body density was calculated using hydrostatic weighing procedures with fat mass ascertained from body density values. Participants were required to pedal maximally on a cycle ergometer (Monark 864 against randomly assigned loads ranging from 70 g·kg-1 - 95 g·kg-1 (using a TBM or FFM protocol for 8 seconds. The resistive force that produced the highest peak power output (PPO for each protocol was considered optimal. Differences (p 0.05 were observed between time to PPO, or heart rate when the TBM and FFM protocols were compared. The findings of this study suggest that when high intensity cycle ergometer resistive forces are derived from FFM, greater peak powers can be obtained consistently in karate athletes. Resistive forces that relate to the active muscle tissue utilised during this type of exercise may need to be explored in preference to protocols that include both lean and fat masses. The findings have implications for both exercise prescription and the evaluation of experimental results concerning karate athletes

Laboratory- and Field-Based Assessment of Maximal Aerobic Power of Elite Stand-Up Paddle-Board Athletes.

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Schram, Ben; Hing, Wayne; Climstein, Mike

2016-01-01

Stand-up paddle boarding (SUP) is a rapidly growing sport and recreational activity for which only anecdotal evidence exists on its proposed health, fitness, and injury-rehabilitation benefits. 10 internationally and nationally ranked elite SUP athletes. Participants were assessed for their maximal aerobic power on an ergometer in a laboratory and compared with other water-based athletes. Field-based assessments were subsequently performed using a portable gas-analysis system, and a correlation between the 2 measures was performed. Maximal aerobic power (relative) was significantly higher (P = .037) when measured in the field with a portable gas-analysis system (45.48 ± 6.96 mL · kg(-1) · min(-1)) than with laboratory-based metabolic-cart measurements (43.20 ± 6.67 mL · kg(-1) · min(-1)). There was a strong, positive correlation (r = .907) between laboratory and field maximal aerobic power results. Significantly higher (P = .000) measures of SUP paddling speed were found in the field than with the laboratory ergometer (+42.39%). There were no significant differences in maximal heart rate between the laboratory and field settings (P = .576). The results demonstrate the maximal aerobic power representative of internationally and nationally ranked SUP athletes and show that SUP athletes can be assessed for maximal aerobic power in the laboratory with high correlation to field-based measures. The field-based portable gas-analysis unit has a tendency to consistently measure higher oxygen consumption. Elite SUP athletes display aerobic power outputs similar to those of other upper-limb-dominant elite water-based athletes (surfing, dragon-boat racing, and canoeing).

Psychophysiological effects of synchronous versus asynchronous music during cycling.

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Lim, Harry B T; Karageorghis, Costas I; Romer, Lee M; Bishop, Daniel T

2014-02-01

Synchronizing movement to a musical beat may reduce the metabolic cost of exercise, but findings to date have been equivocal. Our aim was to examine the degree to which the synchronous application of music moderates the metabolic demands of a cycle ergometer task. Twenty-three recreationally active men made two laboratory visits. During the first visit, participants completed a maximal incremental ramp test on a cycle ergometer. At the second visit, they completed four randomized 6-min cycling bouts at 90% of ventilatory threshold (control, metronome, synchronous music, and asynchronous music). Main outcome variables were oxygen uptake, HR, ratings of dyspnea and limb discomfort, affective valence, and arousal. No significant differences were evident for oxygen uptake. HR was lower under the metronome condition (122 ± 15 bpm) compared to asynchronous music (124 ± 17 bpm) and control (125 ± 16 bpm). Limb discomfort was lower while listening to the metronome (2.5 ± 1.2) and synchronous music (2.3 ± 1.1) compared to control (3.0 ± 1.5). Both music conditions, synchronous (1.9 ± 1.2) and asynchronous (2.1 ± 1.3), elicited more positive affective valence compared to metronome (1.2 ± 1.4) and control (1.2 ± 1.2), while arousal was higher with synchronous music (3.4 ± 0.9) compared to metronome (2.8 ± 1.0) and control (2.8 ± 0.9). Synchronizing movement to a rhythmic stimulus does not reduce metabolic cost but may lower limb discomfort. Moreover, synchronous music has a stronger effect on limb discomfort and arousal when compared to asynchronous music.

Somatotype variables related to strength and power output in male basketball players.

Science.gov (United States)

Buśko, Krzysztof; Pastuszak, Anna; Lipińska, Monika; Lipińska, Marta; Gryko, Karol

2017-01-01

The purpose of this study was to investigate the relationship between somatotype, muscular strength, power output measured in maximal cycle ergometer exercise bouts, and maximal power output and height of rise of the body mass centre (jump height) measured in akimbo counter movement jump (ACMJ), counter movement jump (CMJ) and spike jump (SPJ), in male basketball players. Thirteen male basketball players (second division, age 19.4 ± 0.8 years, body height 192.9 ± 5.6 cm, body mass 88.8 ± 8.6 kg, training experience 9.3 ± 0.8 years) participated in the study. Somatotype was determined using the Heath-Carter method. Maximal joint torques were measured under static conditions. Power output was measured in 2 maximal cycle ergometer exercise bouts, 10 seconds each, with increasing external loads equal to 7.5 and 10.0% of the body weight (BW). All jump trials (ACMJ, CMJ and SPJ) were performed on a force plate. The mean somatotype of basketball players amounted to: 2.8-4.2-3.2. The sum of the joint torques for left and right lower extremities (0.613), trunk (0.631) and all six measured muscle groups (0.647) were significantly correlated (p jump during ACMJ, CMJ and SPJ trials. The power output measured in maximal cycle ergometer exercise bouts with increasing external loads was significantly correlated (p basketball players' anthropometric characteristics can influence their level of performance but it is not a decisive factor.

Energy systems contributions in 2,000 m race simulation: a comparison among rowing ergometers and water.

Science.gov (United States)

de Campos Mello, Fernando; de Moraes Bertuzzi, Rômulo Cássio; Grangeiro, Patricia Moreno; Franchini, Emerson

2009-11-01

This study investigated the energy system contributions of rowers in three different conditions: rowing on an ergometer without and with the slide and rowing in the water. For this purpose, eight rowers were submitted to 2,000 m race simulations in each of the situations defined above. The fractions of the aerobic (W (AER)), anaerobic alactic (W (PCR)) and anaerobic lactic (W ([La-])) systems were calculated based on the oxygen uptake, the fast component of excess post-exercise oxygen uptake and changes in net blood lactate, respectively. In the water, the metabolic work was significantly higher [(851 (82) kJ] than during both ergometer [674 (60) kJ] and ergometer with slide [663 (65) kJ] (P systems were water = 87 (2), 7 (2) and 6 (2)%, ergometer = 84 (2), 7 (2) and 9 (2)%, and ergometer with the slide = 84 (2), 7 (2) and 9 (1)%. VO2, HR and lactate were not different among conditions. These results seem to indicate that the ergometer braking system simulates conditions of a bigger and faster boat and not a single scull. Probably, a 2,500 m test should be used to properly simulate in the water single-scull race.

Design Analysis And Applications Of A Regenerative Bicycle Ergometer

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Chukwuneke J. L.

2015-08-01

Full Text Available Man needs to do some form of physical work in other to remain healthy this work is similar to the work done by any machine or equipment and thus should be channeled to give useful output but rather it is usually dissipated into the environment in form of heat. The regenerative bicycle ergometer takes advantage of the greater power generated by the limbs and arms thus conserves converts and stores the energy dissipated by the rider with an ideal mechanical advantage of 7.6 it strategically uses simple mechanisms to magnify its work and then converts this mechanical energy into electrical energy by the use of a dynamo with a speed ratio of 108.5 and a transmission efficiency of 89 the rider pedals 27rpm to obtain the dynamos rated input of 2600rpm giving an output of 12.6volts. The regenerative bicycle ergometer is designed and constructed to perform all the core functions of a bicycle ergometer having an allowable load of 116.5kg and a maximum resistance of 65.33N which is equivalent to a mass of 6.66kg. The energy converted is stored in a 12volts battery making its use flexible clean and meeting the energy demands of man.

Effects of rehydration and food consumption on salivary flow, pH and buffering capacity in young adult volunteers during ergometer exercise.

Science.gov (United States)

Tanabe, Mai; Takahashi, Toshiyuki; Shimoyama, Kazuhiro; Toyoshima, Yukako; Ueno, Toshiaki

2013-10-28

The aim of this study was to investigate the influences of rehydration and food consumption on salivary flow, pH, and buffering capacity during bicycle ergometer exercise in participants. Ten healthy volunteers exercised on a bicycle ergometer at 80% of their maximal heart rate. These sessions lasted for two periods of 20 min separated by 5-min rest intervals. Volunteers were subjected to one of the following conditions: (1) no water (mineral water) or food consumption, (2) only water for rehydration, (3) water and food consumption, (4) a sports drink only for rehydration, and (5) rehydration with a sports drink and food. Statistical significance was assessed using one-way analysis of variance and Dunnett's test (p salivary pH decreased significantly during and after exercise in conditions 4 and 5. The salivary buffering capacity decreased significantly during exercise and/or after the exercise in conditions 1, 3, 4, and 5. The results showed that salivary pH and buffering capacity decreased greatly depending on the combination of a sports drink and food.

Effects of Hemopure on maximal oxygen uptake and endurance performance in healthy humans.

Science.gov (United States)

Ashenden, M J; Schumacher, Y O; Sharpe, K; Varlet-Marie, E; Audran, M

2007-05-01

Haemoglobin-based oxygen carriers (HBOCs) such as Hemopure are touted as a tenable substitute for red blood cells and therefore potential doping agents, although the mechanisms of oxygen transport of HBOCs are incompletely understood. We investigated whether infusion of Hemopure increased maximal oxygen uptake (V.O 2max) and endurance performance in healthy subjects. Twelve male subjects performed two 4-minute submaximal exercise bouts equivalent to 60 % and 75 % of V.O (2max) on a cycle ergometer, followed by a ramped incremental protocol to elicit V.O (2max). A crossover design tested the effect of infusing either 30 g (6 subjects) or 45 g (6 subjects) of Hemopure versus a placebo. Under our study conditions, Hemopure did not increase V.O (2max) nor endurance performance. However, the infusion of Hemopure caused a decrease in heart rate of approximately 10 bpm (p=0.009) and an average increase in mean ( approximately 7 mmHg) and diastolic blood pressure ( approximately 8 mmHg) (p=0.046) at submaximal and maximal exercise intensities. Infusion of Hemopure did not bestow the same physiological advantages generally associated with infusion of red blood cells. It is conceivable that under exercise conditions, the hypertensive effects of Hemopure counter the performance-enhancing effect of improved blood oxygen carrying capacity.

Development and Validation of an Automated Step Ergometer

Directory of Open Access Journals (Sweden)

C. de Sousa Maria do Socorro

2014-12-01

Full Text Available Laboratory ergometers have high costs, becoming inaccessible for most of the population, hence, it is imperative to develop affordable devices making evaluations like cardiorespiratory fitness feasible and easier. The objective of this study was to develop and validate an Automated Step Ergometer (ASE, adjusted according to the height of the subject, for predicting VO2max through a progressive test. The development process was comprised by three steps, the theoretical part, the prototype assembly and further validation. The ASE consists in an elevating platform that makes the step at a higher or lower level as required for testing. The ASE validation was obtained by comparing the values of predicted VO2max (equation and direct gas analysis on the prototype and on a, treadmill. For the validation process 167 subjects with average age of 31.24 ± 14.38 years, of both genders and different degrees of cardiorespiratory fitness, were randomized and divided by gender and training condition, into untrained (n=106, active (n=24 and trained (n=37 subjects. Each participant performed a progressive test on which the ASE started at the same height (20 cm for all. Then, according to the subject’s height, it varied to a maximum of 45 cm. Time in each stage and rhythm was chosen in accordance with training condition from lowest to highest (60-180 s; 116-160 bpm, respectively. Data was compared with the student’s t test and ANOVA; correlations were tested with Pearson’s r. The value of α was set at 0.05. No differences were found between the predicted VO2max and the direct gas analysis VO2max, nor between the ASE and treadmill VO2max (p= 0.365 with high correlation between ergometers (r= 0.974. The values for repeatability, reproducibility, and reliability of male and female groups measures were, respectively, 4.08 and 5.02; 0.50 and 1.11; 4.11 and 5.15. The values of internal consistency (Cronbach’s alpha among measures were all >0.90. It was verified

Comparison of the effect of different intensity exercise on a bicycle ergometer on postprandial lipidemia in type II diabetic patients

Directory of Open Access Journals (Sweden)

Narges Argani

2014-05-01

Full Text Available BACKGROUND: Postprandial lipid clearance failure and lipoprotein disorders, which are independent risk factors for cardiovascular diseases are well-recognized in type II diabetes. Reduction of fats through exercise has been proved, though the mechanism is not well-defined, and the effects of different intensity exercise on postprandial lipidemia in diabetes type II is unknown. This study aims to find these effects using a cycle ergometer. METHODS: On three different days, 15 type II diabetics (10 women and 5 men, with a mean age 42.07 ± 6.05 years, weight 94.64 ± 4.37 kg, height 159.78 ± 9.09 cm, and body mass index 29.83 ± 3.93 kg/m2, consumed a full fat breakfast (750-800 kcal, 85% fat, and 150 min later, blood samples were taken from them to measure their lipid profile. The 1st day was the control day, without any exercises. Seven days later, 90 min after enriched breakfast, they did 30 min of exercise on the cycle ergometer with intensity of 55-70% of maximum heart rate (HRmax, and 14 days later, 90 min after enriched breakfast, they did 30 min of exercise with intensity of 70-85% of HRmax. RESULTS: According to Friedman non-parametric test, high-density lipoprotein (HDL cholesterol serum level significantly increased after 30 min of moderate intensity exercise (P > 0.05, from 39.4 ± 5.2 to 48.6 ± 9.3, while this increase was insignificant after a higher intensity exercise. Neither intensity levels had any significant effects on triglyceride or on low-density lipoprotein cholesterol. CONCLUSION: Results showed that moderate intensity exercise was more effective in increasing HDL cholesterol level in type II diabetics.   Keywords: Postprandial Lipidemia, Resistance Exercise, Bicycle Ergometer, Type II Diabetes 

Evaluation of the maximized power of a regenerative endoreversible Stirling cycle using the thermodynamic analysis

International Nuclear Information System (INIS)

Ahmadi, Mohammad H.; Mohammadi, Amir H.; Dehghani, Saeed

2013-01-01

Highlights: • The optimal power of an endoreversible Stirling cycle is investigated. • In the endoreversible cycle, external heat transfer processes are considered irreversible. • Optimal temperature of the heat source leading to a maximum power for the cycle is detained. • Effect of design parameters on the power and its corresponding thermal efficiency is studied. - Abstract: In this communication, the optimal power of an endoreversible Stirling cycle with perfect regeneration is investigated. In the endoreversible cycle, external heat transfer processes are irreversible. Optimal temperature of the heat source leading to a maximum power for the cycle is detained. Moreover, effect of design parameters of the Stirling engine on the maximized power of the engine and its corresponding thermal efficiency is studied

Cardiorespiratory Fitness Profile of Undergraduate Biomedical ...

African Journals Online (AJOL)

... for developing sedentary habits, which could lead to reduced cardiorespiratory fitness. ... This study therefore examined the cardiorespiratory fitness (CRF) profile of ... A modified sub-maximal cycle ergometer protocol was used to estimate ...

In dubio pro silentio – Even Loud Music Does Not Facilitate Strenuous Ergometer Exercise

Directory of Open Access Journals (Sweden)

Gunter Kreutz

2018-05-01

Full Text Available Background: Music listening is wide-spread in amateur sports. Ergometer exercise is one such activity which is often performed with loud music.Aim and Hypotheses: We investigated the effects of electronic music at different intensity levels on ergometer performance (physical performance, force on the pedal, pedaling frequency, perceived fatigue and heart rate in healthy adults. We assumed that higher sound intensity levels are associated with greater ergometer performance and less perceived effort, particularly for untrained individuals.Methods: Groups of high trained and low trained healthy males (N = 40; age = 25.25 years; SD = 3.89 years were tested individually on an ergometer while electronic dance music was played at 0, 65, 75, and 85 dB. Participants assessed their music experience during the experiment.Results: Majorities of participants rated the music as not too loud (65%, motivating (77.50%, appropriate for this sports exercise (90%, and having the right tempo (67.50%. Participants noticed changes in the acoustical environment with increasing intensity levels, but no further effects on any of the physical or other subjective measures were found for neither of the groups. Therefore, the main hypothesis must be rejected.Discussion: These findings suggest that high loudness levels do not positively influence ergometer performance. The high acceptance of loud music and perceived appropriateness could be based on erroneous beliefs or stereotypes. Reasons for the widespread use of loud music in fitness sports needs further investigation. Reducing loudness during fitness exercise may not compromise physical performance or perceived effort.

In dubio pro silentio – Even Loud Music Does Not Facilitate Strenuous Ergometer Exercise

Science.gov (United States)

Kreutz, Gunter; Schorer, Jörg; Sojke, Dominik; Neugebauer, Judith; Bullack, Antje

2018-01-01

Background: Music listening is wide-spread in amateur sports. Ergometer exercise is one such activity which is often performed with loud music. Aim and Hypotheses: We investigated the effects of electronic music at different intensity levels on ergometer performance (physical performance, force on the pedal, pedaling frequency), perceived fatigue and heart rate in healthy adults. We assumed that higher sound intensity levels are associated with greater ergometer performance and less perceived effort, particularly for untrained individuals. Methods: Groups of high trained and low trained healthy males (N = 40; age = 25.25 years; SD = 3.89 years) were tested individually on an ergometer while electronic dance music was played at 0, 65, 75, and 85 dB. Participants assessed their music experience during the experiment. Results: Majorities of participants rated the music as not too loud (65%), motivating (77.50%), appropriate for this sports exercise (90%), and having the right tempo (67.50%). Participants noticed changes in the acoustical environment with increasing intensity levels, but no further effects on any of the physical or other subjective measures were found for neither of the groups. Therefore, the main hypothesis must be rejected. Discussion: These findings suggest that high loudness levels do not positively influence ergometer performance. The high acceptance of loud music and perceived appropriateness could be based on erroneous beliefs or stereotypes. Reasons for the widespread use of loud music in fitness sports needs further investigation. Reducing loudness during fitness exercise may not compromise physical performance or perceived effort. PMID:29867622

Determination of the exercise intensity that elicits maximal fat oxidation in individuals with obesity.

Science.gov (United States)

Dandanell, Sune; Præst, Charlotte Boslev; Søndergård, Stine Dam; Skovborg, Camilla; Dela, Flemming; Larsen, Steen; Helge, Jørn Wulff

2017-04-01

Maximal fat oxidation (MFO) and the exercise intensity that elicits MFO (Fat Max ) are commonly determined by indirect calorimetry during graded exercise tests in both obese and normal-weight individuals. However, no protocol has been validated in individuals with obesity. Thus, the aims were to develop a graded exercise protocol for determination of Fat Max in individuals with obesity, and to test validity and inter-method reliability. Fat oxidation was assessed over a range of exercise intensities in 16 individuals (age: 28 (26-29) years; body mass index: 36 (35-38) kg·m -2 ; 95% confidence interval) on a cycle ergometer. The graded exercise protocol was validated against a short continuous exercise (SCE) protocol, in which Fat Max was determined from fat oxidation at rest and during 10 min of continuous exercise at 35%, 50%, and 65% of maximal oxygen uptake. Intraclass and Pearson correlation coefficients between the protocols were 0.75 and 0.72 and within-subject coefficient of variation (CV) was 5 (3-7)%. A Bland-Altman plot revealed a bias of -3% points of maximal oxygen uptake (limits of agreement: -12 to 7). A tendency towards a systematic difference (p = 0.06) was observed, where Fat Max occurred at 42 (40-44)% and 45 (43-47)% of maximal oxygen uptake with the graded and the SCE protocol, respectively. In conclusion, there was a high-excellent correlation and a low CV between the 2 protocols, suggesting that the graded exercise protocol has a high inter-method reliability. However, considerable intra-individual variation and a trend towards systematic difference between the protocols reveal that further optimization of the graded exercise protocol is needed to improve validity.

Physiological responses to indoor rock-climbing and their relationship to maximal cycle ergometry.

Science.gov (United States)

Sheel, A William; Seddon, Nicholas; Knight, Andrew; McKenzie, Donald C; R Warburton, Darren E

2003-07-01

To quantify the cardiorespiratory responses to indoor climbing during two increasingly difficult climbs and relate them to whole-body dynamic exercise. It was hypothesized that as climbing difficulty increased, oxygen consumption ([V02] and heart rate would increase, and that climbing would require utilization of a significant fraction of maximal cycling values. Elite competitive sport rock climbers (6 male, 3 female) completed two data collection sessions. The first session was completed at an indoor climbing facility, and the second session was an incremental cycle test to exhaustion. During indoor climbing subjects were randomly assigned to climb two routes designated as "harder" or "easier" based on their previous best climb. Subjects wore a portable metabolic system, which allowed measurement of oxygen consumption [V02], minute ventilation ([V02]E), respiratory exchange ratio (RER), and heart rate. During the second session, maximal values for [V02], [V02]E, RER, and heart rate were determined during an incremental cycle test to exhaustion. Heart rate and [VO2], expressed as percent of cycling maximum, were significantly higher during harder climbing compared with easier climbing. During harder climbing, %HR(max) was significantly higher than %[V02] (2max) (89.6% vs 51.2%), and during easier climbing, %HR(max) was significantly higher than %[V02] (2max) (66.9% vs 45.3%). With increasing levels of climbing difficulty, there is a rise in both heart rate and [V02]. However, there is a disproportional rise in heart rate compared with [V02], which we attribute to the fact that climbing requires the use of intermittent isometric contractions of the arm musculature and the reliance of both anaerobic and aerobic metabolism.

MOTION CAPTURE AS A MODERN TECHNOLOGY FOR ANALYSING ERGOMETER ROWING

Directory of Open Access Journals (Sweden)

Maria Skublewska-Paszkowska

2016-03-01

Full Text Available The paper presents a purpose-built laboratory stand consisting of a Vicon motion capture system with reference video cameras, wireless EMG system, Concept 2 Indoor Rower ergometer, wireless heart rate monitor and the Nexus software. A pilot study of people who exercise on the ergometer helped to create a proper configuration of all the components of the laboratory. Moreover, a procedure for carrying out research was developed, which consists of several steps divided into 4 stages: preparation of the motion acquisition system; preparation of the participant; familiarising participants with the technique of rowing, recording their movements and acquiring other measurement signals. Preliminary analysis of the results obtained from heterogeneous signals from various devices showed that all the components of the research stand are mutually compatible and the received signals do not interfere with one another.

The effects of slow- and fast-rhythm classical music on progressive cycling to voluntary physical exhaustion.

Science.gov (United States)

Szabo, A; Small, A; Leigh, M

1999-09-01

To investigate, based on the parallel information processing model and arousal hypothesis, whether musical tempo and its manipulation during exercise affect the maximal workload (watts) achieved during progressive cycling. repeated measures experiment that involved one control and four treatment conditions. the experiment was performed in a controlled laboratory environment. twenty-four male and female volunteers, recruited from among a University population, were tested. the data collection proceeded in five counterbalanced test-sessions that included control (C), slow music (SM), fast music (FM) slow to fast music (SFM) and fast to slow music (FSM) interventions. In the last two conditions, musical tempo was changed when the participant's maximal HR reserve has reached 70%. In all test-sessions, participants started to cycle at 50 watts and then the workload was increased in increments of 25 watts every minute until self-declared exhaustion. Maximal ergometer cycling was defined as the workload at the last completed minute of exercise. workload, HR, and postexperimental ratings of test-session preferences were the dependent measures. Significantly higher workload was accomplished in the SFM condition. No between-session differences were seen in HR. The results also yielded significantly better "efficiency", in terms of workload/HR reserve ratio, in the SFM session. PARTICIPANTS preferred the FM and SFM sessions more than the other sessions. Switching to FM during progressive exercise results in the accomplishment of more work without proportional changes in HR. These effects may be due to distraction from fatigue and are, apparently, dependent on the attention capturing strength of the distracting stimulus.

Supra maximal bicycle tests do not detect seasonable progress in groups of elite speed skaters

NARCIS (Netherlands)

van Ingen Schenau, G.J.; Bakker, F.C.; de Groot, G.; de Koning, J.J.

1992-01-01

Seven female and eight male elite junior skaters performed cycle ergometer tests at four different times during the 1987/1988 season. The tests consisted of a Wingate-type 30-s sprint test and a 2.5-min supramaximal test. The subjects were tested in February, May and September 1987 and in January

Automatic determination of pressurized water reactor core loading patterns which maximize end-of-cycle reactivity within power peaking and burnup constraints

International Nuclear Information System (INIS)

Hobson, G.H.

1985-01-01

An automated procedure for determining the optimal core loading pattern for a pressurized water reactor which maximizes end-of-cycle k/sub eff/ while satisfying constraints on power peaking and discharge burnup has been developed. The optimization algorithm combines a two energy group, two-dimensional coarse-mesh finite difference diffusion theory neutronics model to simulate core conditions, a perturbation theory approach to determine reactivity, flux, power and burnup changes as a function of assembly shuffling, and Monte Carlo integer programming to select the optimal loading pattern solution. The core examined was a typical Cycle 2 reload with no burnable poisons. Results indicate that the core loading pattern that maximizes end-of-cycle k/sub eff/ results in a 5.4% decrease in fuel cycle costs compared with the core loading pattern that minimizes the maximum relative radial power peak

Physiological responses and exercise preference between the Trikke and the bicycle ergometer

Directory of Open Access Journals (Sweden)

Eddie T.C. Lam

2016-06-01

Conclusion: Participants were more efficient in using the Trikke than the bicycle ergometer. The Trikke may be an enjoyable alternative for those individuals, particularly women, who have lost interest in traditional forms of exercise.

Automatic determination of pressurized water reactor core loading patterns that maximize beginning-of-cycle reactivity within power-peaking and burnup constraints

International Nuclear Information System (INIS)

Hobson, G.H.; Turinsky, P.J.

1986-01-01

Computational capability has been developed to automatically determine a good estimate of the core loading pattern, which minimizes fuel cycle costs for a pressurized water reactor (PWR). Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern that maximizes core reactivity while satisfying power peaking, discharge burnup, and other constraints. The method utilizes a two-dimensional, coarse-mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern. First-order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, end-of-cycle burnup. Monte Carlo integer programming is then used to determine a near-optimal loading pattern within a range of loading patterns near the reference pattern. The process then repeats with the new loading pattern as the reference loading pattern and terminates when no better loading pattern can be determined. The process was applied with both reactivity maximization and radial power-peaking minimization as objectives. Results on a typical large PWR indicate that the cost of obtaining an 8% improvement in radial power-peaking margin is ≅2% in fuel cycle costs, for the reload core loaded without burnable poisons that was studied

The relationship between blood potassium, blood lactate, and electromyography signals related to fatigue in a progressive cycling exercise test.

Science.gov (United States)

Tenan, Matthew S; McMurray, Robert G; Blackburn, B Troy; McGrath, Melanie; Leppert, Kyle

2011-02-01

Local muscle fatigue may be related to potassium efflux from the muscle cell and/or lactate accumulation within the muscle. Local fatigue causes a decrease in median frequency (MPF) of the electromyogram's power spectrum during isometric contractions but its relationship to changes in potassium and lactate during dynamic exercise is equivocal. Thus, this investigation evaluated relationships between changes in the MPF from the vastus lateralis and blood levels of lactate and potassium during an incremental cycling test and recovery. Trained cyclists (n=8) completed a discontinuous, graded cycle test to exhaustion under normal and glycogen-reduced conditions. The glycogen reduced condition promoted an environment of lower lactate production while permitting a consistent potassium response. Blood samples and maximal isometric EMG data were collected at the end of each stage and during recovery. Maximal lactate levels were ∼ 60% lower in the glycogen reduced condition; potassium was similar between trials. MPF did not change significantly at volitional fatigue. Further, MPF was not significantly related to lactate (p>0.27) or potassium (p>0.16) in either condition. Though both lactate and potassium have been implicated as factors relating to local muscle fatigue, neither is significantly related to changes in MPF during or after progressive exercise on a cycle ergometer. Copyright © 2010 Elsevier Ltd. All rights reserved.

Underwater Cycle Ergometry: Power Requirements With and Without Diver Thermal Dress

National Research Council Canada - National Science Library

Shykoff, B

2009-01-01

.... An ongoing problem has been that, although the power requirement of cycling in the water is known to be greater than that in air for the same ergometer setting, the magnitude of the difference...

The effect of running versus cycling high-intensity intermittent exercise on local tissue oxygenation and perceived enjoyment in 18-30-year-old sedentary men.

Science.gov (United States)

Kriel, Yuri; Askew, Christopher D; Solomon, Colin

2018-01-01

High-intensity interval training (HIIT) has been proposed as a time-efficient exercise format to improve exercise adherence, thereby targeting the chronic disease burden associated with sedentary behaviour. Exercise mode (cycling, running), if self-selected, will likely affect the physiological and enjoyment responses to HIIT in sedentary individuals. Differences in physiological and enjoyment responses, associated with the mode of exercise, could potentially influence the uptake and continued adherence to HIIT. It was hypothesised that in young sedentary men, local and systemic oxygen utilisation and enjoyment would be higher during a session of running HIIT, compared to a session of cycling HIIT. A total of 12 sedentary men (mean ± SD; age 24 ± 3 years) completed three exercise sessions: a maximal incremental exercise test on a treadmill (MAX) followed by two experiment conditions, (1) free-paced cycling HIIT on a bicycle ergometer (HIITCYC) and (2) constant-paced running HIIT on a treadmill ergometer (HIITRUN). Deoxygenated haemoglobin (HHb) in the gastrocnemius (GN), the left vastus lateralis (LVL) and the right vastus lateralis (RVL) muscles, oxygen consumption (VO 2 ), heart rate (HR), ratings of perceived exertion (RPE) and physical activity enjoyment (PACES) were measured during HIITCYC and HIITRUN. There was a higher HHb in the LVL ( p = 0.001) and RVL ( p = 0.002) sites and a higher VO 2 ( p = 0.017) and HR ( p HIIT produces higher levels of physiological stress when compared to constant-paced running HIIT. Participants perceived running HIIT to be more enjoyable than cycling HIIT. These findings have implications for selection of mode of HIIT for physical stress, exercise enjoyment and compliance.

The effect of time trial cycling position on physiological and aerodynamic variables.

Science.gov (United States)

Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

2015-01-01

To reduce aerodynamic resistance cyclists lower their torso angle, concurrently reducing Peak Power Output (PPO). However, realistic torso angle changes in the range used by time trial cyclists have not yet been examined. Therefore the aim of this study was to investigate the effect of torso angle on physiological parameters and frontal area in different commonly used time trial positions. Nineteen well-trained male cyclists performed incremental tests on a cycle ergometer at five different torso angles: their preferred torso angle and at 0, 8, 16 and 24°. Oxygen uptake, carbon dioxide expiration, minute ventilation, gross efficiency, PPO, heart rate, cadence and frontal area were recorded. The frontal area provides an estimate of the aerodynamic drag. Overall, results showed that lower torso angles attenuated performance. Maximal values of all variables, attained in the incremental test, decreased with lower torso angles (P aerodynamic drag and physiological functioning.

The effect of running versus cycling high-intensity intermittent exercise on local tissue oxygenation and perceived enjoyment in 18–30-year-old sedentary men

Science.gov (United States)

Solomon, Colin

2018-01-01

Background High-intensity interval training (HIIT) has been proposed as a time-efficient exercise format to improve exercise adherence, thereby targeting the chronic disease burden associated with sedentary behaviour. Exercise mode (cycling, running), if self-selected, will likely affect the physiological and enjoyment responses to HIIT in sedentary individuals. Differences in physiological and enjoyment responses, associated with the mode of exercise, could potentially influence the uptake and continued adherence to HIIT. It was hypothesised that in young sedentary men, local and systemic oxygen utilisation and enjoyment would be higher during a session of running HIIT, compared to a session of cycling HIIT. Methods A total of 12 sedentary men (mean ± SD; age 24 ± 3 years) completed three exercise sessions: a maximal incremental exercise test on a treadmill (MAX) followed by two experiment conditions, (1) free-paced cycling HIIT on a bicycle ergometer (HIITCYC) and (2) constant-paced running HIIT on a treadmill ergometer (HIITRUN). Deoxygenated haemoglobin (HHb) in the gastrocnemius (GN), the left vastus lateralis (LVL) and the right vastus lateralis (RVL) muscles, oxygen consumption (VO2), heart rate (HR), ratings of perceived exertion (RPE) and physical activity enjoyment (PACES) were measured during HIITCYC and HIITRUN. Results There was a higher HHb in the LVL (p = 0.001) and RVL (p = 0.002) sites and a higher VO2 (p = 0.017) and HR (p HIIT produces higher levels of physiological stress when compared to constant-paced running HIIT. Participants perceived running HIIT to be more enjoyable than cycling HIIT. These findings have implications for selection of mode of HIIT for physical stress, exercise enjoyment and compliance.

Testes de broncoprovocação com metacolina e com exercício em bicicleta e corrida livre em crianças com asma intermitente Bronchial provocation tests using methacholine, cycle ergometer exercise and free running in children with intermittent asthma

Directory of Open Access Journals (Sweden)

Ana C. T. G. Souza

2005-02-01

Full Text Available OBJETIVO: Comparar a responsividade de vias aéreas à metacolina e ao teste de exercício na bicicleta ergométrica e corrida livre em crianças com asma intermitente. MÉTODOS: Estudo randomizado. Trinta crianças de ambos os sexos com asma intermitente participaram do estudo. Cada teste foi realizado em 3 dias diferentes, através de randomização: a broncoprovocação com metacolina, método do dosímetro; b teste de exercício: corrida livre em um corredor de 50 m; c teste de exercício: bicicleta ergométrica com ar seco. A freqüência cardíaca atingida foi 80 a 90% da freqüência cardíaca máxima. A espirometria foi realizada aos 3, 6, 10, 15, 20 e 30 minutos após o exercício. Broncoespasmo induzido por exercício foi definido como a queda de volume expiratório forçado no primeiro segundo (VEF1 > 10% em relação aos valores pré-teste. RESULTADOS: A média de idade foi 11±3 anos. O VEF1 e VEF1/CVF (capacidade vital forçada foram normais e similares antes dos três testes de broncoprovocação. A freqüência cardíaca máxima foi de 178±7 bpm durante o exercício na bicicleta e 181±6 bpm na corrida livre (p > 0,05. Broncoespasmo significante foi visto em 23 crianças após o teste com metacolina, em 19 após a corrida livre e em 14 crianças após exercício em bicicleta (p OBJECTIVE: To compare airway responsiveness to methacholine, cycle ergometer exercise and free running in children with intermittent asthma. METHODS: A randomized study was conducted with 30 children of both genders with intermittent asthma. Each child was submitted to challenge testing on three separate days, in random order: a Methacholine challenge using a dosimeter; b Exercise challenge testing - free running along a 50-meter-long corridor; c Dry-air exercise challenge on a cycle ergometer. Target heart rate during exercise was 80 to 90% of the maximum predicted value. Spirometry was performed 3, 6,10,15,20 and 30 minutes after exercise. Exercise

ATP and phosphocreatine utilization in single human muscle fibres during the development of maximal power output at elevated muscle temperatures.

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Gray, Stuart R; Söderlund, Karin; Ferguson, Richard A

2008-05-01

In this study, we examined the effect of muscle temperature (Tm) on adenosine triphosphate (ATP) and phosphocreatine utilization in single muscle fibres during the development of maximal power output in humans. Six male participants performed a 6-s maximal sprint on a friction-braked cycle ergometer under both normal (Tm = 34.3 degrees C, s = 0.6) and elevated (T(m) = 37.3 degrees C, s = 0.2) muscle temperature conditions. During the elevated condition, muscle temperature of the legs was raised, passively, by hot water immersion followed by wrapping in electrically heated blankets. Muscle biopsies were taken from the vastus lateralis before and immediately after exercise. Freeze-dried single fibres were dissected, characterized according to myosin heavy chain composition, and analysed for ATP and phosphocreatine content. Single fibres were classified as: type I, IIA, IIAX25 (1 - 25% IIX isoform), IIAX50 (26 - 50% IIX), IIAX75 (51 - 75% IIX), or IIAX100 (76 - 100% IIX). Maximal power output and pedal rate were both greater (P < 0.05) during the elevated condition by 258 W (s = 110) and 22 rev . min(-1) (s = 6), respectively. In both conditions, phosphocreatine content decreased significantly in all fibre types, with a greater decrease during the elevated condition in type IIA fibres (P < 0.01). Adenosine triphosphate content was also reduced to a greater (P < 0.01) extent in type IIA fibres during the elevated condition. The results of the present study indicate that after passive elevation of muscle temperature, there was a greater decrease in ATP and phosphocreatine content in type IIA fibres than in the normal trial, which contributed to the higher maximal power output.

Low-protein vegetarian diet does not have a short-term effect on blood acid–base status but raises oxygen consumption during submaximal cycling

Directory of Open Access Journals (Sweden)

Hietavala Enni-Maria

2012-11-01

Full Text Available Abstract Background Acid–base balance refers to the equilibrium between acids and bases in the human body. Nutrition may affect acid–base balance and further physical performance. With the help of PRAL (potential renal acid load, a low-protein vegetarian diet (LPVD was designed to enhance the production of bases in body. The aim of this study was to investigate if LPVD has an effect on blood acid–base status and performance during submaximal and maximal aerobic cycling. Methods Nine healthy, recreationally active men (age 23.5 ± 3.4 yr participated in the study and were randomly divided into two groups in a cross-over study design. Group 1 followed LPVD for 4 days and group 2 ate normally (ND before performing a cycle ergometer test. The test included three 10-min stages at 40, 60 and 80% of VO2max. The fourth stage was performed at 100% of VO2max until exhaustion. After 10–16 days, the groups started a second 4-day diet, and at the end performed the similar ergometer test. Venous blood samples were collected at the beginning and at the end of both diet periods and after every stage cycled. Results Diet caused no significant difference in venous blood pH, strong ion difference (SID, total concentration of weak acids (Atot, partial pressure of CO2 (pCO2 or HCO3- at rest or during cycling between LPVD and ND. In the LPVD group, at rest SID significantly increased over the diet period (38.6 ± 1.8 vs. 39.8 ± 0.9, p=0.009. Diet had no significant effect on exercise time to exhaustion, but VO2 was significantly higher at 40, 60 and 80% of VO2max after LPVD compared to ND (2.03 ± 0.25 vs. 1.82 ± 0.21 l/min, p=0.035; 2.86 ± 0.36 vs. 2.52 ± 0.33 l/min, p Conclusion There was no difference in venous blood acid–base status between a 4-day LPVD and ND. VO2 was increased during submaximal cycling after LPVD suggesting that the exercise economy was poorer. This had no further effect on maximal aerobic performance. More studies are needed to

Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle.

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Gibbs, David L; Shmulevich, Ilya

2017-06-01

The Influence Maximization Problem (IMP) aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf.

Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle

Science.gov (United States)

Shmulevich, Ilya

2017-01-01

The Influence Maximization Problem (IMP) aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf. PMID:28628618

Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle.

Directory of Open Access Journals (Sweden)

David L Gibbs

2017-06-01

Full Text Available The Influence Maximization Problem (IMP aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf.

The key kinematic determinants of undulatory underwater swimming at maximal velocity.

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Connaboy, Chris; Naemi, Roozbeh; Brown, Susan; Psycharakis, Stelios; McCabe, Carla; Coleman, Simon; Sanders, Ross

2016-01-01

The optimisation of undulatory underwater swimming is highly important in competitive swimming performance. Nineteen kinematic variables were identified from previous research undertaken to assess undulatory underwater swimming performance. The purpose of the present study was to determine which kinematic variables were key to the production of maximal undulatory underwater swimming velocity. Kinematic data at maximal undulatory underwater swimming velocity were collected from 17 skilled swimmers. A series of separate backward-elimination analysis of covariance models was produced with cycle frequency and cycle length as dependent variables (DVs) and participant as a fixed factor, as including cycle frequency and cycle length would explain 100% of the maximal swimming velocity variance. The covariates identified in the cycle-frequency and cycle-length models were used to form the saturated model for maximal swimming velocity. The final parsimonious model identified three covariates (maximal knee joint angular velocity, maximal ankle angular velocity and knee range of movement) as determinants of the variance in maximal swimming velocity (adjusted-r2 = 0.929). However, when participant was removed as a fixed factor there was a large reduction in explained variance (adjusted r2 = 0.397) and only maximal knee joint angular velocity continued to contribute significantly, highlighting its importance to the production of maximal swimming velocity. The reduction in explained variance suggests an emphasis on inter-individual differences in undulatory underwater swimming technique and/or anthropometry. Future research should examine the efficacy of other anthropometric, kinematic and coordination variables to better understand the production of maximal swimming velocity and consider the importance of individual undulatory underwater swimming techniques when interpreting the data.

Improved lower extremity pedaling mechanics in individuals with stroke under maximal workloads.

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Linder, Susan M; Rosenfeldt, Anson B; Bazyk, Andrew S; Koop, Mandy Miller; Ozinga, Sarah; Alberts, Jay L

2018-05-01

Background Individuals with stroke present with motor control deficits resulting in the abnormal activation and timing of agonist and antagonist muscles and inefficient movement patterns. The analysis of pedaling biomechanics provides a window into understanding motor control deficits, which vary as a function of workload. Understanding the relationship between workload and motor control is critical when considering exercise prescription during stroke rehabilitation. Objectives To characterize pedaling kinematics and motor control processes under conditions in which workload was systematically increased to an eventual patient-specific maximum. Methods A cohort study was conducted in which 18 individuals with chronic stroke underwent a maximal exertion cardiopulmonary exercise test on a stationary cycle ergometer, during which pedaling torque was continuously recorded. Measures of force production, pedaling symmetry, and pedaling smoothness were obtained. Results Mean Torque increased significantly (p pedaling action, improved from 0.37(0.29) to 0.29(0.35) during downstroke (p = 0.007), and worsened during the upstroke: -0.37(0.38) to -0.62(0.46) (p pedaling improved significantly from initial to terminal workloads (p pedaling kinematics at terminal workloads indicate that individuals with stroke demonstrate improved motor control with respect to the timing, sequencing, and activation of hemiparetic lower extremity musculature compared to lower workloads. Therapeutic prescription involving higher resistance may be necessary to sufficiently engage and activate the paretic lower extremity.

Time perception, pacing and exercise intensity: maximal exercise distorts the perception of time

OpenAIRE

Edwards, A. M.; McCormick, A.

2017-01-01

Introduction\\ud \\ud Currently there are no data examining the impact of exercise on the perception of time, which is surprising as optimal competitive performance is dependent on accurate pacing using knowledge of time elapsed.\\ud \\ud \\ud Methods\\ud \\ud With institutional ethics approval, 12 recreationally active adult participants (f = 7, m = 5) undertook both 30 s Wingate cycles and 20 min (1200 s) rowing ergometer bouts as short and long duration self-paced exercise trials, in each of thre...

Optimization and experimental validation of a thermal cycle that maximizes entropy coefficient fisher identifiability for lithium iron phosphate cells

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Mendoza, Sergio; Rothenberger, Michael; Hake, Alison; Fathy, Hosam

2016-03-01

This article presents a framework for optimizing the thermal cycle to estimate a battery cell's entropy coefficient at 20% state of charge (SOC). Our goal is to maximize Fisher identifiability: a measure of the accuracy with which a parameter can be estimated. Existing protocols in the literature for estimating entropy coefficients demand excessive laboratory time. Identifiability optimization makes it possible to achieve comparable accuracy levels in a fraction of the time. This article demonstrates this result for a set of lithium iron phosphate (LFP) cells. We conduct a 24-h experiment to obtain benchmark measurements of their entropy coefficients. We optimize a thermal cycle to maximize parameter identifiability for these cells. This optimization proceeds with respect to the coefficients of a Fourier discretization of this thermal cycle. Finally, we compare the estimated parameters using (i) the benchmark test, (ii) the optimized protocol, and (iii) a 15-h test from the literature (by Forgez et al.). The results are encouraging for two reasons. First, they confirm the simulation-based prediction that the optimized experiment can produce accurate parameter estimates in 2 h, compared to 15-24. Second, the optimized experiment also estimates a thermal time constant representing the effects of thermal capacitance and convection heat transfer.

Skeletal muscle ATP turnover and muscle fiber conduction velocity are elevated at higher muscle temperatures during maximal power output development in humans.

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Gray, Stuart R; De Vito, Giuseppe; Nimmo, Myra A; Farina, Dario; Ferguson, Richard A

2006-02-01

The effect of temperature on skeletal muscle ATP turnover and muscle fiber conduction velocity (MFCV) was studied during maximal power output development in humans. Eight male subjects performed a 6-s maximal sprint on a mechanically braked cycle ergometer under conditions of normal (N) and elevated muscle temperature (ET). Muscle temperature was passively elevated through the combination of hot water immersion and electric blankets. Anaerobic ATP turnover was calculated from analysis of muscle biopsies obtained before and immediately after exercise. MFCV was measured during exercise using surface electromyography. Preexercise muscle temperature was 34.2 degrees C (SD 0.6) in N and 37.5 degrees C (SD 0.6) in ET. During ET, the rate of ATP turnover for phosphocreatine utilization [temperature coefficient (Q10) = 3.8], glycolysis (Q10 = 1.7), and total anaerobic ATP turnover [Q10 = 2.7; 10.8 (SD 1.9) vs. 14.6 mmol x kg(-1) (dry mass) x s(-1) (SD 2.3)] were greater than during N (P < 0.05). MFCV was also greater in ET than in N [3.79 (SD 0.47) to 5.55 m/s (SD 0.72)]. Maximal power output (Q10 = 2.2) and pedal rate (Q10 = 1.6) were greater in ET compared with N (P < 0.05). The Q10 of maximal and mean power were correlated (P < 0.05; R = 0.82 and 0.85, respectively) with the percentage of myosin heavy chain type IIA. The greater power output obtained with passive heating was achieved through an elevated rate of anaerobic ATP turnover and MFCV, possibly due to a greater effect of temperature on power production of fibers, with a predominance of myosin heavy chain IIA at the contraction frequencies reached.

Effects of Cycling vs. Running Training on Endurance Performance in Preparation for Inline Speed Skating.

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Stangier, Carolin; Abel, Thomas; Hesse, Clemens; Claen, Stephanie; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

2016-06-01

Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean ± SD 24 ± 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: ∼52% of V[Combining Dot Above]O2peak: 500 kcal per session). Before and after the training intervention, all athletes performed an incremental specific (inline speed skating) and 1 nonspecific (cycling or running) step test according to the group affiliation. In addition to blood lactate concentration, oxygen uptake (V[Combining Dot Above]O2), ventilatory equivalent (VE/V[Combining Dot Above]O2), respiratory exchange ratio (RER), and heart rate were measured. The specific posttest revealed significantly increased absolute V[Combining Dot Above]O2peak values (2.9 ± 0.4, 3.4 ± 0.7, p = 0.01) and submaximal V[Combining Dot Above]O2 values (p ≤ 0.01). VE/V[Combining Dot Above]O2 and RER significantly decreased at maximal (46.6 ± 6.6, 38.5 ± 3.4, p = 0.005; 1.1 ± 0.03, 1.0 ± 0.04, p = 0.001) and submaximal intensities (p ≤ 0.04). None of the analysis revealed a significant group effect (p ≥ 0.15). The results indicate that both cycling vs. running exercise at ∼52% of V[Combining Dot Above]O2peak had a positive effect on the athletes' endurance performance. The increased submaximal V[Combining Dot Above]O2 values indicate a reduction in athletes' inline speed skating technique. Therefore, athletes would benefit from a focus on technique training in the subsequent period.

Competitor presence reduces internal attentional focus and improves 16.1km cycling time trial performance.

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Williams, Emily L; Jones, Hollie S; Andy Sparks, S; Marchant, David C; Midgley, Adrian W; Mc Naughton, Lars R

2015-07-01

Whilst the presence of a competitor has been found to improve performance, the mechanisms influencing the change in selected work rates during direct competition have been suggested but not specifically assessed. The aim was to investigate the physiological and psychological influences of a visual avatar competitor during a 16.1-km cycling time trial performance, using trained, competitive cyclists. Randomised cross-over design. Fifteen male cyclists completed four 16.1km cycling time trials on a cycle ergometer, performing two with a visual display of themselves as a simulated avatar (FAM and SELF), one with no visual display (DO), and one with themselves and an opponent as simulated avatars (COMP). Participants were informed the competitive avatar was a similar ability cyclist but it was actually a representation of their fastest previous performance. Increased performance times were evident during COMP (27.8±2.0min) compared to SELF (28.7±1.9min) and DO (28.4±2.3min). Greater power output, speed and heart rate were apparent during COMP trial than SELF (pperformance. Competitive cyclists performed significantly faster during a 16.1-km competitive trial than when performing maximally, without a competitor. The improvement in performance was elicited due to a greater external distraction, deterring perceived exertion. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Methodological Considerations on the Relationship Between the 1,500-M Rowing Ergometer Performance and Vertical Jump in National-Level Adolescent Rowers.

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Maciejewski, Hugo; Rahmani, Abderrahmane; Chorin, Frédéric; Lardy, Julien; Samozino, Pierre; Ratel, Sébastien

2018-03-12

The purpose of the present study was to investigate whether three different approaches for evaluating squat jump performance were correlated to rowing ergometer performance in elite adolescent rowers. Fourteen young male competitive rowers (15.3 ± 0.6 years), who took part in the French rowing national championships, performed a 1,500-m all-out rowing ergometer performance (P1500) and a squat jump (SJ) test. The performance in SJ was determined by calculating the jump height (HSJ in cm), a jump index (ISJ = HSJ · body mass · gravity, in J) and the mean power output (PSJ in W) from the Samozino et al.'s method. Furthermore, allometric modelling procedures were used to consider the importance of body mass (BM) in the assessment of HSJ, ISJ and PSJ, and their relationships with between P1500 and jump scores. P1500 was significantly correlated to HSJ (r2 = 0.29, P jump and rowing ergometer performances at the same rate, and that PSJ could be the best correlate of P1500. Therefore, the calculation of power seems to be more relevant than HSJ and ISJ to (i) evaluate jump performance, and (ii) infer the capacity of adolescent rowers to perform 1,500-m all-out rowing ergometer performance, irrespective of their body mass. This could help coaches to improve their training program and potentially identify talented young rowers.

Change in maximal fat oxidation in response to different regimes of periodized high-intensity interval training (HIIT).

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Astorino, Todd A; Edmunds, Ross M; Clark, Amy; Gallant, Rachael; King, Leesa; Ordille, Gina M; Heath, Brendyn; Montell, Matthew; Bandong, Jason

2017-04-01

Increased capacity for fat oxidation (FatOx) is demonstrated in response to chronic endurance training as well as high-intensity interval training (HIIT). This study examined changes in maximal fat oxidation (MFO) in response to 20 sessions of periodized HIIT in an attempt to identify if various regimes of HIIT similarly augment capacity for FatOx. Thirty-nine habitually active men and women (mean age and VO 2 max = 22.5 ± 4.4 year and 40.0 ± 5.6 mL/kg/min) completed training and 32 men and women with similar physical activity and fitness level served as non-exercising controls (CON). Training consisted of ten sessions of progressive low-volume HIIT on the cycle ergometer after which participants completed an additional ten sessions of sprint interval training (SIT), high-volume HIIT, or periodized HIIT, whose assignment was randomized. Before and throughout training, MFO, FatOx, and carbohydrate oxidation (CHOOx) were assessed during progressive cycling to exhaustion. Compared to CON, there was no effect of HIIT on MFO (p = 0.11). Small increases (p = 0.03) in FatOx were evident in response to HIIT leading to an additional 4.3 g of fat oxidized, although this value may not be clinically meaningful. Our results refute the widely reported increases in capacity for FatOx demonstrated with HIIT, which is likely due to marked day-to-day variability in determinations of MFO and exercise fat oxidation as well as the heterogeneity of our sample.

運動疫学研究の成果に基づく味の素におけるヘルスプロモーションの展開

OpenAIRE

長沼, 由紀子; 甲斐, 裕子; 熊谷, 秋三

2003-01-01

The purpose of the present study was to examine the relationship between endurance fitness level and the prevalence of hypertension, diabetes mellitus and dyslipidemia in Japanese men. The subjects were 906 Japanese men aged 19-60 years. Maximal oxygen uptake (VO2max) was predicted using a cycle ergometer as an index of endurance fitness. Subjects were classified into four groups; G1 (VO2max

Maximal heart rate does not limit cardiovascular capacity in healthy humans

DEFF Research Database (Denmark)

Munch, G D W; Svendsen, J H; Damsgaard, R

2014-01-01

In humans, maximal aerobic power (VO2 max ) is associated with a plateau in cardiac output (Q), but the mechanisms regulating the interplay between maximal heart rate (HRmax) and stroke volume (SV) are unclear. To evaluate the effect of tachycardia and elevations in HRmax on cardiovascular function...... and capacity during maximal exercise in healthy humans, 12 young male cyclists performed incremental cycling and one-legged knee-extensor exercise (KEE) to exhaustion with and without right atrial pacing to increase HR. During control cycling, Q and leg blood flow increased up to 85% of maximal workload (WLmax...... and RAP (P healthy...

Effects of 16-week high-intensity interval training using upper and lower body ergometers on aerobic fitness and morphological changes in healthy men: a preliminary study

Directory of Open Access Journals (Sweden)

Osawa Y

2014-11-01

Full Text Available Yusuke Osawa,1,2,* Koichiro Azuma,3,* Shogo Tabata,3 Fuminori Katsukawa,2 Hiroyuki Ishida,2 Yuko Oguma,2 Toshihide Kawai,4 Hiroshi Itoh,4 Shigeo Okuda,5 Hideo Matsumoto3 1Japan Society for the Promotion of Science, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan; 2Sports Medicine Research Center, Keio University, Kanagawa, Japan; 3Institute for Integrated Sports Medicine, School of Medicine, Keio University, Tokyo, Japan; 4Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan; 5Department of Radiology, School of Medicine, Keio University, Tokyo, Japan *Yusuke Osawa and Koichiro Azuma are co-first authors of this article Abstract: It is unclear whether combined leg and arm high-intensity interval training (HIIT improves fitness and morphological characteristics equal to those of leg-based HIIT programs. The aim of this study was to compare the effects of HIIT using leg-cycling (LC and arm-cranking (AC ergometers with an HIIT program using only LC. Effects on aerobic capacity and skeletal muscle were analyzed. Twelve healthy male subjects were assigned into two groups. One performed LC-HIIT (n=7 and the other LC- and AC-HIIT (n=5 twice weekly for 16 weeks. The training programs consisted of eight to 12 sets of >90% VO2 (the oxygen uptake that can be utilized in one minute peak for 60 seconds with a 60-second active rest period. VO2 peak, watt peak, and heart rate were measured during an LC incremental exercise test. The cross-sectional area (CSA of trunk and thigh muscles as well as bone-free lean body mass were measured using magnetic resonance imaging and dual-energy X-ray absorptiometry. The watt peak increased from baseline in both the LC (23%±38%; P<0.05 and the LC–AC groups (11%±9%; P<0.05. The CSA of the quadriceps femoris muscles also increased from baseline in both the LC (11%±4%; P<0.05 and the LC–AC groups (5%±5%; P<0.05. In contrast, increases were observed in the CSA of

Lactate minimum in a ramp protocol and its validity to estimate the maximal lactate steady state

Directory of Open Access Journals (Sweden)

Emerson Pardono

2009-01-01

Full Text Available http://dx.doi.org/10.5007/1980-0037.2009v11n2p174   The objectives of this study were to evaluate the validity of the lactate minimum (LM using a ramp protocol for the determination of LM intensity (LMI, and to estimate the exercise intensity corresponding to maximal blood lactate steady state (MLSS. In addition, the possibility of determining aerobic and anaerobic fitness was investigated. Fourteen male cyclists of regional level performed one LM protocol on a cycle ergometer (Excalibur–Lode consisting of an incremental test at an initial workload of 75 Watts, with increments of 1 Watt every 6 seconds. Hyperlactatemia was induced by a 30-second Wingate anaerobic test (WAT (Monark–834E at a workload corresponding to 8.57% of the volunteer’s body weight. Peak power (11.5±2 Watts/kg, mean power output (9.8±1.7 Watts/kg, fatigue index (33.7±2.3% and lactate 7 min after WAT (10.5±2.3 mmol/L were determined. The incremental test identified LMI (207.8±17.7 Watts and its respective blood lactate concentration (2.9±0.7 mmol/L, heart rate (153.6±10.6 bpm, and also maximal aerobic power (305.2±31.0 Watts. MLSS intensity was identified by 2 to 4 constant exercise tests (207.8±17.7 Watts, with no difference compared to LMI and good agreement between the two parameters. The LM test using a ramp protocol seems to be a valid method for the identification of LMI and estimation of MLSS intensity in regional cyclists. In addition, both anaerobic and aerobic fitness parameters were identified during a single session.

A physiological and biomechanical comparison of over-ground, treadmill and ergometer wheelchair propulsion.

Science.gov (United States)

Mason, Barry; Lenton, John; Leicht, Christof; Goosey-Tolfrey, Victoria

2014-01-01

The purpose of the study was to determine which laboratory-based modality provides the most valid physiological and biomechanical representation of over-ground sports wheelchair propulsion. Fifteen able-bodied participants with previous experience of wheelchair propulsion performed a 3-minute exercise trial at three speeds (4, 6 and 8 km ∙ h(-1)) in three testing modalities over separate sessions: (i) over-ground propulsion on a wooden sprung surface; (ii) wheelchair ergometer propulsion; (iii) treadmill propulsion at four different gradients (0%, 0.7%, 1.0% and 1,3%). A 0.7% treadmill gradient was shown to best reflect the oxygen uptake (7.3 to 9.1% coefficient of variation (CV)) and heart rate responses (4.9 to 6.4% CV) of over-ground propulsion at 4 and 6 km ∙ h(-1). A 1.0% treadmill gradient provided a more valid representation of oxygen uptake during over-ground propulsion at 8 km ∙ h(-1) (8.6% CV). Physiological demand was significantly underestimated in the 0% gradient and overestimated in the 1.3% gradient and wheelchair ergometer trials compared to over-ground trials (Ppropulsion at lower speeds (4 and 6 km ∙ h(-1)) whereas a 1.0% gradient may be more suitable at 8 km ∙ h(-1).

The effect of Sub-maximal exercise-rehabilitation program on cardio-respiratory endurance indexes and oxygen pulse in patients with spastic cerebral palsy

Directory of Open Access Journals (Sweden)

M Izadi

2006-05-01

Full Text Available Background: Physical or cardio-respiratory fitness are of the best important physiological variables in children with cerebral palsy (CP, but the researches on exercise response of individuals with CP are limited. Our aim was to determine the effect of sub-maximal rehabilitation program (aerobic exercise on maximal oxygen uptake, oxygen pulse and cardio- respiratory physiological variables of children with moderate to severe spastic cerebral palsy diplegia and compare with able-bodied children. Methods: In a controlled clinical trial study, 15 children with diplegia spastic cerebral palsy, were recruited on a voluntarily basis (experimental group and 18 subjects without neurological impairments selected as control group. In CP group, aerobic exercise program performed on the average of exercise intensity (144 beat per minute of heart rate, 3 times a week for 3 months. The time of each exercise session was 20-25 minutes. Dependent variables were measured in before (pretest and after (post test of rehabilitation program through Mac Master Protocol on Tantories cycle ergometer in CP group and compared with the control group. Results: The oxygen pulse (VO2/HR during ergometery protocol was significantly lower in CP group than normal group (P<0.05. No significant statistical difference in maximal oxygen uptake (VO2 max was found between groups. The rehabilitation program leads to little increase of this variable in CP group. After sub-maximal exercise in pretest and post test, the heart rate of patient group was greater than control group, and aerobic exercise leads to significant decrease in heart rate in CP patients(P<0.05. Conclusion: The patients with spastic cerebral palsy, because of high muscle tone, severe spasticity and involuntarily movements have higher energy cost and lower aerobic fitness than normal people. The rehabilitation exercise program can improve physiological function of muscle and cardio-respiratory endurance in these

Prediction of performance in Vasaloppet through long lasting ski- ergometer and rollerski tests in cross-country skiers

DEFF Research Database (Denmark)

Mygind, Erik; Wulff, Kristian; Jensen, Mads Rosenkilde

2015-01-01

-ergometer and Rollerski field tests correlate strongly with performance in Vasaloppet and therefore might be useful test tools for recreational skiers who wish to participate in long lasting c-c competitions. Keywords: Cross-country ski training, Upper body, Exercise intensity, Field test, Body composition blood lactate......The main purpose was to investigate if long lasting cross-country (c-c) test procedures could predict performance time in ‘Vasaloppet’ and secondly the effect of a 16 weeks training period on a 90 min double poling performance test. 24 moderate trained c-c skiers participated in the study...... and completed Vasaloppet. All skiers carried out pre and post training tests in a 90 minutes ski-ergometer double poling test and a 120 minutes rollerski field test on a closed paved circuit. 19 skiers provided detailed training logs that could sufficiently establish their training preparation for Vasaloppet...

Noncircular Chainrings Do Not Influence Maximum Cycling Power.

Science.gov (United States)

Leong, Chee-Hoi; Elmer, Steven J; Martin, James C

2017-12-01

Noncircular chainrings could increase cycling power by prolonging the powerful leg extension/flexion phases, and curtailing the low-power transition phases. We compared maximal cycling power-pedaling rate relationships, and joint-specific kinematics and powers across 3 chainring eccentricities (CON = 1.0; LOW ecc  = 1.13; HIGH ecc  = 1.24). Part I: Thirteen cyclists performed maximal inertial-load cycling under 3 chainring conditions. Maximum cycling power and optimal pedaling rate were determined. Part II: Ten cyclists performed maximal isokinetic cycling (120 rpm) under the same 3 chainring conditions. Pedal and joint-specific powers were determined using pedal forces and limb kinematics. Neither maximal cycling power nor optimal pedaling rate differed across chainring conditions (all p > .05). Peak ankle angular velocity for HIGH ecc was less than CON (p pedal system allowed cyclists to manipulate ankle angular velocity to maintain their preferred knee and hip actions, suggesting maximizing extension/flexion and minimizing transition phases may be counterproductive for maximal power.

Aerobic training in myotonia congenita

DEFF Research Database (Denmark)

Andersen, Grete; Løkken, Nicoline; Vissing, John

2017-01-01

Introduction: Exercise has not been investigated in myotonia congenita (MC). We investigated whether regular aerobic training can reduce myotonia and improve fitness. Methods: Untrained patients with MC (age: 24–62 years; n = 6) completed 28 ± 3 sessions of 30-minute cycle ergometer training at 75......–17%; P = 0.02) and maximal workload by 10% (95% CI, 3–18%; P = 0.03). None of the myotonia tests changed in a clinically meaningful way. Conclusions: Regular endurance training improves fitness and maximal workload performance in patients with MC. The lack of creatine kinase elevations indicates...

Lactate and ammonia concentration in blood and sweat during incremental cycle ergometer exercise

NARCIS (Netherlands)

Ament, W; Huizenga, [No Value; Mook, GA; Gips, CH; Verkerke, GJ

It is known that the concentrations of ammonia and lactate in blood increase during incremental exercise. Sweat also contains lactate and ammonia. The aim of the present study was to investigate the physiological response of lactate and ammonia in plasma and sweat during a stepwise incremental cycle

Oral Consumption of Vitamin K2 for 8 Weeks Associated With Increased Maximal Cardiac Output During Exercise.

Science.gov (United States)

McFarlin, Brian K; Henning, Andrea L; Venable, Adam S

2017-07-01

Background • Vitamin K1 and K2 are not typically common in a Western diet because they are found in a variety of fermented foods. Vitamin K2 in particular has been demonstrated to restore mitochondrial function and has a key role in production of mitochondrial adenosine triphosphate. Thus, it is reasonable to speculate that dietary supplementation with vitamin K2 could increase the function of muscle with high mitochondrial content (ie, skeletal and cardiac muscle). Objective • The purpose of this study was to determine if 8 wk of dietary supplementation with Vitamin K2 could alter cardiovascular responses to a graded cycle ergometer test. Design • The study was a randomized controlled trial. Setting • The study took place in the Applied Physiology Laboratory of the Department of Biological Sciences at the University of North Texas (Denton, TX, USA). Participants • Participants were aerobically trained males and female athletes (N = 26). Intervention • Participants were randomly assigned either to a control group that received a rice flour placebo or to an intervention group that received vitamin K2. For weeks 1 to 4, participants received 300 mg/d; for weeks 5 to 8, they received 150 mg/d. Subjects assigned to the control group received similar doses to mirror the intervention group. Subjects consumed the supplements during an 8-wk period while they maintained their typical exercise habits. Outcome Measures • At baseline and postintervention, participants completed a standard, graded exercise test on an electronically braked cycle ergometer. Before the test, participants were fitted with a mouth piece, and their oxygen consumption, carbon dioxide production, respiratory rate, and respiratory exchange ratio were measured. In addition, participants were fitted with skin-mounted electrodes that measured noninvasive cardiac output, stroke volume, and heart rate. To assess the cumulative exercise change, an area-under-the-curve (AUC) value was calculated

Sprint performance and propulsion asymmetries on an ergometer in trained high- and low-point wheelchair rugby players

NARCIS (Netherlands)

Goosey-Tolfrey, Victoria L; Vegter, Riemer J K; Mason, Barry S; Paulson, Thomas A W; Lenton, John P; van der Scheer, Jan W; van der Woude, Lucas H V

The purpose of this study was to examine the propulsion asymmetries of wheelchair athletes while sprinting on an instrumented, dual-roller ergometer system. Eighteen experienced wheelchair rugby players (8 low point (LP) (class 1.5) and 10 high point (HP) (class 2.0)) performed a 15-second sprint in

[Physiological differences between cycling and running].

Science.gov (United States)

Millet, Grégoire

2009-08-05

This review compares the differences in systemic responses (VO2max, anaerobic threshold, heart rate and economy) and in underlying mechanisms of adaptation (ventilatory and hemodynamic and neuromuscular responses) between cycling and running. VO2max is specific to the exercise modality. Overall, there is more physiological training transfer from running to cycling than vice-versa. Several other physiological differences between cycling and running are discussed: HR is different between the two activities both for maximal and sub-maximal intensities. The delta efficiency is higher in running. Ventilation is more impaired in cycling than running due to mechanical constraints. Central fatigue and decrease in maximal strength are more important after prolonged exercise in running than in cycling.

Biochemical changes in relation to a maximal exercise test in patients with fibromyalgia

DEFF Research Database (Denmark)

Nørregaard, J; Bülow, P M; Mehlsen, J

1994-01-01

Patients with fibromyalgia often complain of fatigue and pain during exercise and of worsening of pain days after exercise. The aim of the study described here was to determine if abnormal changes in potassium or lactate could be observed during an exercise test in fibromyalgia. Whether an abnormal...... incline in plasma creatine kinase or myoglobin could be observed days after the test was studied also. Fifteen female fibromyalgia patients and 15 age- and sex-matched controls performed a stepwise incremental maximal bicycle-ergometer test. Blood samples were collected from a catheter in a cubital vein......-1 was reached at a heart rate of 124 min-1 in the patients with fibromyalgia as compared to 140 min-1 in the controls (P = 0.02). In relation to workload, the patients scored higher on a Borg scale for perceived exertion during exercise, but if the Borg score was related to lactate no significant...

Indexes of power and aerobic capacity obtained in cycle ergometry and treadmill running: comparisons between sedentary, runners, cyclists and triathletes

Directory of Open Access Journals (Sweden)

Fabrizio Caputo

2003-08-01

Full Text Available The objectives of this study were: a to determine, in a cross-sectional manner, the effect of aerobic training on the peak oxygen uptake (O2peak, the intensity at O2peak (IO2peak and the anaerobic threshold (AnT during running and cycling; and b to verify if the transference of the training effects are dependent on the analized type of exercise or physiological index. Eleven untrained males (UN, nine endurance cyclists (EC, seven endurance runners (ER, and nine triathletes (TR were submitted, on separate days, to incremental tests until voluntary exhaustion on a mechanical braked cycle ergometer and on a treadmill. The values of O2peak (ml.kg-1.min-1 obtained in running and cycle ergometer (ER = 68.8 ± 6.3 and 62.0 ± 5.0; EC = 60.5 ± 8.0 and 67.6 ± 7.6; TR = 64.5 ± 4.8 and 61.0 ± 4.1; UN = 43.5 ± 7.0 and 36.7 ± 5.6; respectively were higher in the group that presented specific training in the modality. The UN group presented the lower values of O2peak, regardless of the type of exercise. This same behavior was observed for the AnT (ml.kg-1.min-1 determined in running and cycle ergometer (ER = 56.8 ± 6.9 and 44.8 ± 5.7; EC = 51.2 ± 5.2 and 57.6 ± 7.1; TR = 56.5 ± 5.1 and 49.0 ± 4.8; UN = 33.2 ± 4.2 and 22.6 ± 3.7; respectively. It can be concluded that the transference of the training effects seems to be only partial, independently of the index (O2peak, IO2peak or AnT or exercise type (running or cycling. In relation to the indices, the specificity of training seems to be less present in the O2peak than in the IO2peak and the AnT.

EFFECT OF ENERGY EXPENDITURE AND TRAINING STATUS ON LEPTIN RESPONSE TO SUB-MAXIMAL CYCLING

Directory of Open Access Journals (Sweden)

Anissa Bouassida

2009-06-01

Full Text Available We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR and 7 untrained (UTR subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP. Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively. [Lep] was related to body fat percentage and body fat mass in TR (r = 0. 84, p < 0.05 and r = 0.93, p < 0.01 and in UTR (r = 0.89, p < 0.01 and r = 0.92, p < 0. 01, respectively. [Lep] did not change significantly during both protocols for both groups but was lower (p < 0.05 in all sampling in TR when compared to UTR. Plasma [I] decreased (p < 0.01 and [GH] increased (p < 0.01 significantly during both SP and PP and these hormones remained lower (I: p < 0.01 and higher (GH: p < 0.01 than pre-exercise levels after a 2-h recovery period, returning to base-line at 24-h recovery. Plasma [La] increased (p < 0.01 during both protocols for TR and UTR. There was no significant change in [C] and [G] during and after both protocols for all subjects. It is concluded that 1 leptin is not sensitive to acute short or prolonged sub-maximal exercises (with energy expenditure under 800 kcal in volleyball/ anaerobically trained athletes as in untrained subjects, 2 volleyball athletes showed significantly lower resting and exercise leptin response with respect to untrained subjects and 3 it appears that in these anaerobically trained athletes leptin response to exercise is more sensitive to the level of

Human calf muscular metabolism study with a home-made ergometer using 31P NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Peynsaert, J; Achten, E; Claeys, E [Ghent University Hospital (Belgium); Rousseaux, M [Ghent University Hospital (Belgium). Dept. of Sport Medicine

1995-12-01

Phosphorus-31 NMR measurements were performed to examine the variations in the concentration of phosphate metabolites in calf muscle during exercise. Therefore, volunteers, installed in the supine position, were asked to push repetitively on the pedal of a home-made ergometer. The produced work and the changes in phosphorus containing metabolites were measured continuously. Correlations were made between the inorganic phosphate/phosphocreatine ratio and the cumulative work and between the intracellular pH and the cumulative work. The exercise protocol could be changed interactively with respect to the imposed initial pressure, the maximum pressure, the pressure increase per level and the time a certain level was held. The whole experiment could be graphically followed on-line. In the first stadium, the in vitro reproducibility of the ergometer was tested for different protocols. These tests revealed that, though the deviation in produced work was markedly the highest at high working pressures, the relative error never exceeded 3%. Consequently, the ex vitro reproducibility of the data was examined with the equipment placed in the scanner. Generally, same conclusions could be derived. In a next stage, the work will be synchronized with the biochemical data. Extreme precautions will be taken to examine each volunteer every time under the same physical and psychological conditions.

Human calf muscular metabolism study with a home-made ergometer using 31P NMR spectroscopy

International Nuclear Information System (INIS)

Peynsaert, J.; Achten, E.; Claeys, E. . Dept. of Magnetic Resonance; Rousseaux, M.

1995-01-01

Phosphorus-31 NMR measurements were performed to examine the variations in the concentration of phosphate metabolites in calf muscle during exercise. Therefore, volunteers, installed in the supine position, were asked to push repetitively on the pedal of a home-made ergometer. The produced work and the changes in phosphorus containing metabolites were measured continuously. Correlations were made between the inorganic phosphate/phosphocreatine ratio and the cumulative work and between the intracellular pH and the cumulative work. The exercise protocol could be changed interactively with respect to the imposed initial pressure, the maximum pressure, the pressure increase per level and the time a certain level was held. The whole experiment could be graphically followed on-line. In the first stadium, the in vitro reproducibility of the ergometer was tested for different protocols. These tests revealed that, though the deviation in produced work was markedly the highest at high working pressures, the relative error never exceeded 3%. Consequently, the ex vitro reproducibility of the data was examined with the equipment placed in the scanner. Generally, same conclusions could be derived. In a next stage, the work will be synchronized with the biochemical data. Extreme precautions will be taken to examine each volunteer every time under the same physical and psychological conditions

Aerobic fitness of Anglo-Saxon and Indian students.

Science.gov (United States)

Hardy, C P; Eston, R G

1985-12-01

The purpose of this study was to compare the aerobic fitness of two groups of male college students: 32 Anglo-Saxon males (age range 16-18 years) with 27 Indian males, born in England, (age range 16-23 years), none of whom was highly active in any particular sport. Maximal oxygen uptake was estimated by submaximal test on a cycle ergometer and percent body fat was assessed by skinfold calipers. The Anglo-Saxon group had higher absolute and relative maximal oxygen consumption values and higher body weight. There was no difference in percent fat between the two groups. Strength data were also provided for descriptive purposes.

Abundance in proteins expressed after functional electrical stimulation cycling or arm cycling ergometry training in persons with chronic spinal cord injury.

Science.gov (United States)

Gorgey, Ashraf S; Graham, Zachary A; Bauman, William A; Cardozo, Christopher; Gater, David R

2017-07-01

Longitudinal design. The study determined the effects of two forms of exercise training on the abundance of two proteins, (glucose transporter-4 [GLUT-4], adenosine monophosphate kinase [AMPK]) involved in glucose utilization and the transcriptional coactivator that regulates the genes involved in energy metabolism and mitochondrial biogenesis (peroxisome proliferator-activated receptor (PPAR) coactivator 1 alpha [PGC-1α]), in muscles in men with chronic motor-complete spinal cord injury (SCI). Clinical trial at a Medical Center. Nine men with chronic motor-complete SCI participated in functional electrical stimulation lower extremity cycling (FES-LEC; n = 4) or arm cycling ergometer (arm-cycling ergometer [ACE]; n = 5) 5 days/week for 16 weeks. Whole body composition was measured by dual energy X-ray absorptiometry. An intravenous glucose tolerance test was performed to measure glucose effectiveness (Sg) and insulin sensitivity (Si). Muscle biopsies of the right vastus lateralis (VL) and triceps muscles were collected one week prior to and post the exercise training intervention. Neither training intervention altered body composition or carbohydrate metabolism. GLUT-4 increased by 3.8 fold in the VL after FES training and increased 0.6 fold in the triceps after ACE training. PGC-1α increased by 2.3 fold in the VL after FES training and 3.8 fold in the triceps after ACE training. AMPK increased by 3.4 fold in the VL after FES training and in the triceps after ACE training. FES-LEC and ACE training were associated with greater protein expressions in the trained muscles by effectively influencing the abundance of GLUT-4, AMPK and PGC-1α. Thus, FES-LEC training of paralyzed muscle can modulate protein expression similar to that of trained and innervated muscle.

Cardiorespiratory Coordination in Repeated Maximal Exercise

Directory of Open Access Journals (Sweden)

Sergi Garcia-Retortillo

2017-06-01

Full Text Available Increases in cardiorespiratory coordination (CRC after training with no differences in performance and physiological variables have recently been reported using a principal component analysis approach. However, no research has yet evaluated the short-term effects of exercise on CRC. The aim of this study was to delineate the behavior of CRC under different physiological initial conditions produced by repeated maximal exercises. Fifteen participants performed 2 consecutive graded and maximal cycling tests. Test 1 was performed without any previous exercise, and Test 2 6 min after Test 1. Both tests started at 0 W and the workload was increased by 25 W/min in males and 20 W/min in females, until they were not able to maintain the prescribed cycling frequency of 70 rpm for more than 5 consecutive seconds. A principal component (PC analysis of selected cardiovascular and cardiorespiratory variables (expired fraction of O2, expired fraction of CO2, ventilation, systolic blood pressure, diastolic blood pressure, and heart rate was performed to evaluate the CRC defined by the number of PCs in both tests. In order to quantify the degree of coordination, the information entropy was calculated and the eigenvalues of the first PC (PC1 were compared between tests. Although no significant differences were found between the tests with respect to the performed maximal workload (Wmax, maximal oxygen consumption (VO2 max, or ventilatory threshold (VT, an increase in the number of PCs and/or a decrease of eigenvalues of PC1 (t = 2.95; p = 0.01; d = 1.08 was found in Test 2 compared to Test 1. Moreover, entropy was significantly higher (Z = 2.33; p = 0.02; d = 1.43 in the last test. In conclusion, despite the fact that no significant differences were observed in the conventionally explored maximal performance and physiological variables (Wmax, VO2 max, and VT between tests, a reduction of CRC was observed in Test 2. These results emphasize the interest of CRC

What is the optimum maximal gonadotropin dosage used in microdose flare-up cycles in poor responders?

Science.gov (United States)

Berkkanoglu, Murat; Ozgur, Kemal

2010-07-01

To find out the optimum maximal dosage of recombinant follicle stimulating hormone (rFSH) in microdose gonadotropin-releasing hormone analog (GnRH-a) flare cycles in poor responders. Prospective randomized study. Private infertility clinic. A total of 119 women were taken into the study. The study group underwent a microdose protocol with a GnRH-agonist followed by rFSH administration. On the third day of GnRH-a administration, 119 patients were randomized in three groups to receive daily fixed doses of 300 IU of rFSH (group A, n = 38), or 450 IU of rFSH (group B, n = 39), or 600 IU of rFSH (group C, n = 42). Peak E(2) levels, days of stimulation with rFSH, total rFSH dosage, total number of oocytes retrieved, M2 oocytes retrieved, total number of embryos, number of embryos transferred, number of Grade-1 embryos transferred, clinical pregnancy rate (positive fetal cardiac activity), and cancellation rates of stimulation and embryo transfer. Clinical pregnancy rates were 13.1%, 15.3%, and 16.1% for group A, group B, and group C, respectively. There were no significant differences in the age, peak serum E(2) concentration, days of stimulation with rFSH, total number of M2 oocytes retrieved, number of embryos transferred, clinical pregnancy rates, and cancellation rates of stimulation and embryo transfer between the three groups except for total rFSH dosage. There is no need to use doses above 300 IU of rFSH to increase the pregnancy rate in microdose cycles. In addition, because the duration of stimulation does not differ between the groups, the usage of 300 IU rFSH in microdose cycles results in less total amount of rFSH consumed in a cycle compared with higher dosages, and this would obviously cost less money to the patients. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Exhaled methane concentration profiles during exercise on an ergometer

Science.gov (United States)

Szabó, A; Ruzsanyi, V; Unterkofler, K; Mohácsi, Á; Tuboly, E; Boros, M; Szabó, G; Hinterhuber, H; Amann, A

2016-01-01

Exhaled methane concentration measurements are extensively used in medical investigation of certain gastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown. Breath methane profiles during ergometer tests were measured by means of a photoacoustic spectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being at least 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 min rest—15 min pedalling (at a workload of 75 W)—5 min rest. In addition, hemodynamic and respiratory parameters were determined and compared to the estimated alveolar methane concentration. The alveolar breath methane level decreased considerably, by a factor of 3–4 within 1.5 min, while the estimated ventilation-perfusion ratio increased by a factor of 2–3. Mean pre-exercise and exercise methane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can be described by the high sensitivity of exhaled methane to ventilationperfusion ratio and are in line with the Farhi equation. PMID:25749807

On Throughput Maximization in Constant Travel-Time Robotic Cells

OpenAIRE

Milind Dawande; Chelliah Sriskandarajah; Suresh Sethi

2002-01-01

We consider the problem of scheduling operations in bufferless robotic cells that produce identical parts. The objective is to find a cyclic sequence of robot moves that minimizes the long-run average time to produce a part or, equivalently, maximizes the throughput rate. The robot can be moved in simple cycles that produce one unit or, in more complicated cycles, that produce multiple units. Because one-unit cycles are the easiest to understand, implement, and control, they are widely used i...

Developing maximal neuromuscular power: part 2 - training considerations for improving maximal power production.

Science.gov (United States)

Cormie, Prue; McGuigan, Michael R; Newton, Robert U

2011-02-01

/or weightlifting exercises performed with loads ranging from 50% to 90% of 1RM appears to be the most potent loading stimulus for improving maximal power in complex movements. Furthermore, plyometric exercises should involve stretch rates as well as stretch loads that are similar to those encountered in each specific sport and involve little to no external resistance. These loading conditions allow for superior transfer to performance because they require similar movement velocities to those typically encountered in sport. Third, it is vital to consider the individual athlete's window of adaptation (i.e. the magnitude of potential for improvement) for each neuromuscular factor contributing to maximal power production when developing an effective and efficient power training programme. A training programme that focuses on the least developed factor contributing to maximal power will prompt the greatest neuromuscular adaptations and therefore result in superior performance improvements for that individual. Finally, a key consideration for the long-term development of an athlete's maximal power production capacity is the need for an integration of numerous power training techniques. This integration allows for variation within power meso-/micro-cycles while still maintaining specificity, which is theorized to lead to the greatest long-term improvement in maximal power.

The comparison of cold-water immersion and cold air therapy on maximal cycling performance and recovery markers following strength exercises

Directory of Open Access Journals (Sweden)

Kane J. Hayter

2016-03-01

Full Text Available This study examined the effects of cold-water immersion (CWI and cold air therapy (CAT on maximal cycling performance (i.e. anaerobic power and markers of muscle damage following a strength training session. Twenty endurance-trained but strength-untrained male (n = 10 and female (n = 10 participants were randomised into either: CWI (15 min in 14 °C water to iliac crest or CAT (15 min in 14 °C air immediately following strength training (i.e. 3 sets of leg press, leg extensions and leg curls at 6 repetition maximum, respectively. Creatine kinase, muscle soreness and fatigue, isometric knee extensor and flexor torque and cycling anaerobic power were measured prior to, immediately after and at 24 (T24, 48 (T48 and 72 (T72 h post-strength exercises. No significant differences were found between treatments for any of the measured variables (p > 0.05. However, trends suggested recovery was greater in CWI than CAT for cycling anaerobic power at T24 (10% ± 2%, ES = 0.90, T48 (8% ± 2%, ES = 0.64 and T72 (8% ± 7%, ES = 0.76. The findings suggest the combination of hydrostatic pressure and cold temperature may be favourable for recovery from strength training rather than cold temperature alone.

Tri-maximal vs. bi-maximal neutrino mixing

International Nuclear Information System (INIS)

Scott, W.G

2000-01-01

It is argued that data from atmospheric and solar neutrino experiments point strongly to tri-maximal or bi-maximal lepton mixing. While ('optimised') bi-maximal mixing gives an excellent a posteriori fit to the data, tri-maximal mixing is an a priori hypothesis, which is not excluded, taking account of terrestrial matter effects

Adiposity, Aerobic Fitness, Muscle Fitness, and Markers of Inflammation in Children

DEFF Research Database (Denmark)

Steene-Johannessen, Jostein; Kolle, Elin; Andersen, Lars Bo

2013-01-01

PURPOSE: The purpose of this study was to describe levels of inflammation markers in Norwegian children and to examine the associations of adiposity, aerobic fitness and muscle fitness with markers of inflammation. METHODS: In 2005-2006, 1467 9-year-olds wererandomly selected from all regions...... explosive, isometric and endurance strength. Aerobic fitness was measured directly during a maximal cycle ergometer test. Adiposity was expressed as waist circumference (WC). RESULTS: The girls had significantly higher levels of CRP, leptin, adiponectin and resistin and lower levels of TNF-α compared...

Caffeine Affects Time to Exhaustion and Substrate Oxidation during Cycling at Maximal Lactate Steady State

Directory of Open Access Journals (Sweden)

Rogério Santos de Oliveira Cruz

2015-06-01

Full Text Available This study analyzed the effects of caffeine intake on whole-body substrate metabolism and exercise tolerance during cycling by using a more individualized intensity for merging the subjects into homogeneous metabolic responses (the workload associated with the maximal lactate steady state—MLSS. MLSS was firstly determined in eight active males (25 ± 4 years, 176 ± 7 cm, 77 ± 11 kg using from two to four constant-load tests of 30 min. On two following occasions, participants performed a test until exhaustion at the MLSS workload 1 h after taking either 6 mg/kg of body mass of caffeine or placebo (dextrose, in a randomized, double-blinded manner. Respiratory exchange ratio was calculated from gas exchange measurements. There was an improvement of 22.7% in time to exhaustion at MLSS workload following caffeine ingestion (95% confidence limits of ±10.3%, p = 0.002, which was accompanied by decrease in respiratory exchange ratio (p = 0.001. These results reinforce findings indicating that sparing of the endogenous carbohydrate stores could be one of the several physiological effects of caffeine during submaximal performance around 1 h.

Similar acute physiological responses from effort and duration matched leg press and recumbent cycling tasks

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James Steele

2018-02-01

Full Text Available The present study examined the effects of exercise utilising traditional resistance training (leg press or ‘cardio’ exercise (recumbent cycle ergometry modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 × 12RM using a 2 s concentric and 3 s eccentric repetition duration controlled with a metronome, thus each set lasted  60 s; recumbent cycle ergometer: 4 × 60 s bouts using a resistance level permitting 80–100 rpm but culminating with being unable to sustain the minimum cadence for the final 5–10 s. Measurements included VO2, respiratory exchange ratio (RER, blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by ‘condition’ in any of the physiological responses examined (all p > 0.05. The present study shows that, when both effort and duration are matched, resistance training (leg press and ‘cardio’ exercise (recumbent cycle ergometry may produce largely similar responses in VO2, RER, blood lactate, energy expenditure, muscle swelling, and electromyography. It therefore seems reasonable to suggest that both may offer a similar stimulus to produce chronic physiological adaptations in outcomes such as cardiorespiratory fitness, strength, and hypertrophy. Future work should look to both replicate the study conducted here with respect to the same, and additional physiological measures, and rigorously test the comparative efficacy of effort and duration matched exercise of differing modalities with respect to chronic improvements in physiological fitness.

Oxygen uptake response to cycle ergometry in post-acute stroke patients with different severity of hemiparesis.

Science.gov (United States)

Chen, Chun-Kai; Weng, Ming-Cheng; Chen, Tien-Wen; Huang, Mao-Hsiung

2013-11-01

This study evaluated the impact of severity of hemiparesis on oxygen uptake (VO2) response in post-acute stroke patients. Sixty-four patients with a mean poststroke interval of 8.6 ± 3.8 days underwent a ramp cardiopulmonary exercise test on a cycling ergometer to volitional termination. Mean peak VO2 (VO2peak) and work efficiency (ΔVO2/ΔWR) were measured by open-circuit spirometry during standard upright ergometer cycling. Severity of the hemiparetic lower limb was assessed by Brunnstrom's motor recovery stages lower extremity (BMRSL). VO2peak was 10% lower in hemiparetic leg with BMRSL V than in that with BMRSL VI, 20% lower in BMRSL IV, and 50% lower in BMRSL III. ΔVO2/ΔWR was higher for the group with increased BMRSL. The relations were consistent after adjustment for age, sex, body mass index, stroke type, hemiparetic side, modified Ashworth Scale, time poststroke, comorbidities, and medications. Our findings revealed that O2peak is dependent on the severity of hemiparesis in leg, and along with ΔO2/ΔWR closely related to the severity of hemiparesis in post-acute stroke patients, regardless of the types and locations of lesion after stroke, as well as the differences in comorbidities and medications. Copyright © 2013. Published by Elsevier B.V.

An Exercise Model to Study Progressive Muscle Fatigue During Constant Work Rate Exercise on a Cycle Ergometer

National Research Council Canada - National Science Library

Fulco, Charles

2003-01-01

... of the same muscles during the activity. However, conventional ergometric testing modes such as stationary cycling or treadmill exercise do not readily lend themselves to quantitating the progressive increase in muscle fatigue...

Size matters: Installed maximal unit size predicts market life cycles of electricity generation technologies and systems

International Nuclear Information System (INIS)

Li, N.

2008-01-01

The electricity generation technologies and systems are complex and change in very dynamic fashions, with a multitude of energy sources and prime movers. Since an important concept in generator design is the 'economies of scale', we discover that the installed maximal unit size (capacity) of the generators is a key 'envelope-pushing' characteristic with logistical behaviors. The logistical wavelet analysis of the max unit sizes for different fuels and prime movers, and the cumulative capacities, reveals universal quantitative features in the aggregate evolution of the power industry. We extract the transition times of the max sizes (spanning 10-90% of the saturation limits) for different technologies and systems, and discover that the max size saturation in the 90-99% range precedes the saturation of cumulative capacities of the corresponding systems in the US. While these universal laws are still empirical, they give us a simple yet elegant framework to examine the evolution of the power industry and markets in predictive, not just descriptive, terms. Such laws give us a quantitative tool to spot trends and predict future development, invaluable in planning and resource allocation based on intrinsic technology and system market life cycles

Modelos para predição da carga máxima no teste clínico de esforço cardiopulmonar Maximal workload prediction models in the clinical cardio-pulmonary effort test

Directory of Open Access Journals (Sweden)

Fernando dos Santos Nogueira

2006-08-01

Full Text Available OBJETIVO: Este estudo buscou derivar equações generalizadas para predição da carga máxima para homens e mulheres jovens. MÉTODOS: O método da ergoespirometria direta (Aerosport® TEEM 100, Estados Unidos da América do Norte foi empregado para determinar o VO2máx e a carga máxima (Wmáx, no cicloergômetro (Monark®, Brasil, de 30 homens (25 ± 5 anos, 75,0 ± 10,7 kg; 48,4 ± 8,8 mL . kg -1 . min -1 e 243 ± 51 Watts e 30 mulheres (26 ± 5 anos, 56,7 ± 5,9 kg, 39,8 ± 7,6 mL . kg -1 . min -1 e 172 ± 37 Watts. A idade e a massa corporal foram empregadas como variáveis independentes. Para todos os testes estatísticos aceitou-se o nível de significância de p OBJECTIVE: This study sought to derive generalized equations for predicting maximal workload for young men and women. METHODS: Direct ergospirometry (Aerosport® TEEM 100, USA was used to determine VO2máx and the maximal work load (Wmax on the cycle ergometer test (Monark®, Brazil of thirty men (25 ± 5 years, 75.0 ± 10.7 kg; 48.4 ± 8.8 mL . kg -1 . min -1 and 243 ± 51 Watts and thirty women (26 ± 5 years, 56.7 ± 5.9 kg, 39.8 ± 7.6 mL . kg -1 . min -1 and 172 ± 37 Watts. Age and body mass were used as independent variables. For all statistic tests, a p < 0.05 significance level was adopted. RESULTS: In the multiple linear adjustment, the maximal workload was explained by age and body mass as 54% (r = 0.73 for men, and as 76% (r = 0.87 for women, with standard errors of 0.66 W . kg -1 and 25 Watts. The proposed equations were cross-validated using another sample with similar age and VO2máx characteristics comprised of fifteen men and fifteen women. The intraclass correlation between the predicted Wmax values and those measures by ergospirometry were 0.70 and 0.69, with standard errors of 28.4 and 15.8 Watts, respectively, for men and women. CONCLUSIONS: This study exhibits valid generalized equations for determining the maximal cycle ergonometer workload for men and

Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism

DEFF Research Database (Denmark)

Mourtzakis, M.; Graham, T.E.; Gonzalez-Alonso, J.

2008-01-01

Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate...... declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70......% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (Pglutamate infusion. Peak...

Phenomenology of maximal and near-maximal lepton mixing

International Nuclear Information System (INIS)

Gonzalez-Garcia, M. C.; Pena-Garay, Carlos; Nir, Yosef; Smirnov, Alexei Yu.

2001-01-01

The possible existence of maximal or near-maximal lepton mixing constitutes an intriguing challenge for fundamental theories of flavor. We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other (x=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter ε(equivalent to)1-2sin 2 θ ex and quantify the present experimental status for |ε| e mixing comes from solar neutrino experiments. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for 10 -8 eV 2 ∼ 2 ∼ -7 eV 2 . In the mass ranges Δm 2 ∼>1.5x10 -5 eV 2 and 4x10 -10 eV 2 ∼ 2 ∼ -7 eV 2 the full interval |ε| e mixing in atmospheric neutrinos, supernova neutrinos, and neutrinoless double beta decay

The influence of aerobic exercise training on the double product break point in low-to-moderate risk adults.

Science.gov (United States)

Hargens, Trent A; Griffin, Diane C; Kaminsky, Leonard A; Whaley, Mitchell H

2011-02-01

The double product is the product of the heart rate and systolic blood pressure. The double product break point (DPBP) is a physiologic threshold that occurs at similar exercise intensities to that of the ventilatory threshold (VT). The influence of aerobic exercise training on the DPBP has not yet been examined. The purpose of this study was to examine whether aerobic exercise training (ET) increases the exercise intensity at which the DPBP occurs, and whether it increases in a similar fashion to the VT. Seven males and 11 females, all sedentary (mean ± SD: age = 29.9 ± 10.5 years) underwent supervised cardiopulmonary exercise testing using a cycle ergometer ramp protocol at baseline and after 8 weeks of vigorous ET on a cycle ergometer. The VT was determined by gas analysis and the V-slope method. Experienced observers using standardized instructions visually determined the DPBP. Following ET, VO(2 peak), maximal workload, and body composition variables all showed significant positive changes. The VO(2) at which the DPBP and VT occurred increased significantly from baseline to follow-up (P fashion to that of the VT, and may be an easier and more useful marker of the VT for exercise training purposes.

Existence of 121 limit cycles in a perturbed planar polynomial Hamiltonian vector field of degree 11

International Nuclear Information System (INIS)

Wang, S.; Yu, P.

2006-01-01

In this article, a systematic procedure has been explored to studying general Z q -equivariant planar polynomial Hamiltonian vector fields for the maximal number of closed orbits and the maximal number of limit cycles after perturbation. Following the procedure by taking special consideration of Z 12 -equivariant vector fields of degree 11, the maximal of 99 closed orbits are obtained under a well-defined coefficient group. Consequently, perturbation parameter control in limit cycle computation leads to the existence of 121 limit cycles in the perturbed Hamiltonian vector field, which gives rise to the lower bound of Hilbert number of 11th-order systems as H(11) ≥ 11 2 . Two conjectures are proposed regarding the maximal number of closed orbits for equivariant polynomial Hamiltonian vector fields and the maximal number of limit cycles bifurcated from the well defined Hamiltonian vector fields after perturbation

Maximal Bell's inequality violation for non-maximal entanglement

International Nuclear Information System (INIS)

Kobayashi, M.; Khanna, F.; Mann, A.; Revzen, M.; Santana, A.

2004-01-01

Bell's inequality violation (BIQV) for correlations of polarization is studied for a product state of two two-mode squeezed vacuum (TMSV) states. The violation allowed is shown to attain its maximal limit for all values of the squeezing parameter, ζ. We show via an explicit example that a state whose entanglement is not maximal allow maximal BIQV. The Wigner function of the state is non-negative and the average value of either polarization is nil

Endocrine Changes In Egyptian Female Olympic Runners

International Nuclear Information System (INIS)

Bayad, M.A.; Fahmy, N.M.

2002-01-01

Circulating levels of testosterone (T), free testosterone (FT), and rostenedione (A) estradial 17-B (E 2 ), dehydroepiandrosterone sulfate (DHEA-S), sex hormone binding globulin (SHBG), luteninzing hormone (LH) and cortisol (C) were estimated by RIA proccdures in the serum of two groups of athletic female runners. An eumenorrheic group (n=10), and an oligomenorrheic group (n=10), and in a healthy regularly menstruating group as control(n=20). The athletes were subjected to a stadardized Ergometer testing aiming at achieving maximal O 2 consumption. Blood samples were with drawn at rest and immediately after exercise in the eumenorrheic and oligomenorrheic groups. Samples from eumenorrheic athletes and control group were at midfollicular phase of the cycle; and randomly in the oligomenorrheicat athlets. Results revealed a state of hypercortisolism in resting eumenorrheic athletes in comparison with control, whereas the oligomenorrheic athletes showed a state of hypercortisolism, hyperandrogenism and hyperestrogenism. The estimated perameters showed remrakable significant increase after the bicycle Ergometer testing, with the exception of SHBG and DHEA-S in the athletic groups

A Comparison of Aerobic Fitness Testing on a Swim Bench and Treadmill in a Recreational Surfing Cohort: A Pilot Study

Directory of Open Access Journals (Sweden)

Hamzeh Khundaqji

2018-06-01

Full Text Available The intermittent manner of surfing accentuates the importance of both the aerobic and anaerobic energy systems. Currently, the optimal method of assessing surfing-specific aerobic fitness is using a swim bench (SWB ergometer; however, their limited availability presents a barrier to surfers wanting to know their maximal aerobic power (VO2peak. As a result, the aims of this pilot study were to determine the VO2peak of recreational surfers using a new commercial SWB ergometer and to propose and examine the feasibility of a regression model to predict SWB ergometer VO2peak values. A total of nine recreational surfers were assessed where body measurements were conducted followed by maximal aerobic capacity testing (swim bench and treadmill to profile the cohort. Findings demonstrated that VO2peak values were significantly greater (p < 0.001 on the treadmill compared to the SWB ergometer (M = 66.01 ± 8.23 vs. 37.41 ± 8.73 mL/kg/min. Peak heart rate was also significantly greater on the treadmill compared to the SWB ergometer. Multiple regression analysis was used to produce a model which predicted SWB VO2peak values with an R2 value of 0.863 and an adjusted R2 value of 0.726. The physiological profiling of the recreational cohort coupled with a surfer’s predicted SWB VO2peak value will allow for identification of surfing-specific aerobic fitness levels and evidence-based training recommendations.

Resistance training and aerobic training improve muscle strength and aerobic capacity in chronic inflammatory demyelinating polyneuropathy

DEFF Research Database (Denmark)

Markvardsen, Lars H; Overgaard, Kristian; Heje, Karen

2018-01-01

after a run-in period of 12 weeks without exercise. Three times weekly the participants performed aerobic exercise on an ergometer bike or resistance exercise with unilateral training of knee and elbow flexion/extension. Primary outcomes were maximal oxygen consumption velocity (VO2 -max) and maximal...

Maximizing and customer loyalty: Are maximizers less loyal?

Directory of Open Access Journals (Sweden)

Linda Lai

2011-06-01

Full Text Available Despite their efforts to choose the best of all available solutions, maximizers seem to be more inclined than satisficers to regret their choices and to experience post-decisional dissonance. Maximizers may therefore be expected to change their decisions more frequently and hence exhibit lower customer loyalty to providers of products and services compared to satisficers. Findings from the study reported here (N = 1978 support this prediction. Maximizers reported significantly higher intentions to switch to another service provider (television provider than satisficers. Maximizers' intentions to switch appear to be intensified and mediated by higher proneness to regret, increased desire to discuss relevant choices with others, higher levels of perceived knowledge of alternatives, and higher ego involvement in the end product, compared to satisficers. Opportunities for future research are suggested.

High-intensity cycle interval training improves cycling and running performance in triathletes.

Science.gov (United States)

Etxebarria, Naroa; Anson, Judith M; Pyne, David B; Ferguson, Richard A

2014-01-01

Effective cycle training for triathlon is a challenge for coaches. We compared the effects of two variants of cycle high-intensity interval training (HIT) on triathlon-specific cycling and running. Fourteen moderately-trained male triathletes ([Formula: see text]O2peak 58.7 ± 8.1 mL kg(-1) min(-1); mean ± SD) completed on separate occasions a maximal incremental test ([Formula: see text]O2peak and maximal aerobic power), 16 × 20 s cycle sprints and a 1-h triathlon-specific cycle followed immediately by a 5 km run time trial. Participants were then pair-matched and assigned randomly to either a long high-intensity interval training (LONG) (6-8 × 5 min efforts) or short high-intensity interval training (SHORT) (9-11 × 10, 20 and 40 s efforts) HIT cycle training intervention. Six training sessions were completed over 3 weeks before participants repeated the baseline testing. Both groups had an ∼7% increase in [Formula: see text]O2peak (SHORT 7.3%, ±4.6%; mean, ±90% confidence limits; LONG 7.5%, ±1.7%). There was a moderate improvement in mean power for both the SHORT (10.3%, ±4.4%) and LONG (10.7%, ±6.8%) groups during the last eight 20-s sprints. There was a small to moderate decrease in heart rate, blood lactate and perceived exertion in both groups during the 1-h triathlon-specific cycling but only the LONG group had a substantial decrease in the subsequent 5-km run time (64, ±59 s). Moderately-trained triathletes should use both short and long high-intensity intervals to improve cycling physiology and performance. Longer 5-min intervals on the bike are more likely to benefit 5 km running performance.

Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism.

Science.gov (United States)

Mourtzakis, M; Graham, T E; González-Alonso, J; Saltin, B

2008-08-01

Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (PTCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33+/-0.07 vs. 0.02+/-0.01 mmol/kg dry wt (dw), PTCA cycle, glutamate and TCA cycle intermediates do not directly affect VO2peak in either trained or untrained muscle.

A New Augmentation Based Algorithm for Extracting Maximal Chordal Subgraphs.

Science.gov (United States)

Bhowmick, Sanjukta; Chen, Tzu-Yi; Halappanavar, Mahantesh

2015-02-01

A graph is chordal if every cycle of length greater than three contains an edge between non-adjacent vertices. Chordal graphs are of interest both theoretically, since they admit polynomial time solutions to a range of NP-hard graph problems, and practically, since they arise in many applications including sparse linear algebra, computer vision, and computational biology. A maximal chordal subgraph is a chordal subgraph that is not a proper subgraph of any other chordal subgraph. Existing algorithms for computing maximal chordal subgraphs depend on dynamically ordering the vertices, which is an inherently sequential process and therefore limits the algorithms' parallelizability. In this paper we explore techniques to develop a scalable parallel algorithm for extracting a maximal chordal subgraph. We demonstrate that an earlier attempt at developing a parallel algorithm may induce a non-optimal vertex ordering and is therefore not guaranteed to terminate with a maximal chordal subgraph. We then give a new algorithm that first computes and then repeatedly augments a spanning chordal subgraph. After proving that the algorithm terminates with a maximal chordal subgraph, we then demonstrate that this algorithm is more amenable to parallelization and that the parallel version also terminates with a maximal chordal subgraph. That said, the complexity of the new algorithm is higher than that of the previous parallel algorithm, although the earlier algorithm computes a chordal subgraph which is not guaranteed to be maximal. We experimented with our augmentation-based algorithm on both synthetic and real-world graphs. We provide scalability results and also explore the effect of different choices for the initial spanning chordal subgraph on both the running time and on the number of edges in the maximal chordal subgraph.

Effects of 16-week high-intensity interval training using upper and lower body ergometers on aerobic fitness and morphological changes in healthy men: a preliminary study.

Science.gov (United States)

Osawa, Yusuke; Azuma, Koichiro; Tabata, Shogo; Katsukawa, Fuminori; Ishida, Hiroyuki; Oguma, Yuko; Kawai, Toshihide; Itoh, Hiroshi; Okuda, Shigeo; Matsumoto, Hideo

2014-01-01

It is unclear whether combined leg and arm high-intensity interval training (HIIT) improves fitness and morphological characteristics equal to those of leg-based HIIT programs. The aim of this study was to compare the effects of HIIT using leg-cycling (LC) and arm-cranking (AC) ergometers with an HIIT program using only LC. Effects on aerobic capacity and skeletal muscle were analyzed. Twelve healthy male subjects were assigned into two groups. One performed LC-HIIT (n=7) and the other LC- and AC-HIIT (n=5) twice weekly for 16 weeks. The training programs consisted of eight to 12 sets of >90% VO2 (the oxygen uptake that can be utilized in one minute) peak for 60 seconds with a 60-second active rest period. VO2 peak, watt peak, and heart rate were measured during an LC incremental exercise test. The cross-sectional area (CSA) of trunk and thigh muscles as well as bone-free lean body mass were measured using magnetic resonance imaging and dual-energy X-ray absorptiometry. The watt peak increased from baseline in both the LC (23%±38%; PHIIT program improves aerobic capacity and muscle hypertrophy in both leg and trunk muscles.

Principles of maximally classical and maximally realistic quantum ...

Indian Academy of Sciences (India)

Principles of maximally classical and maximally realistic quantum mechanics. S M ROY. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India. Abstract. Recently Auberson, Mahoux, Roy and Singh have proved a long standing conjecture of Roy and Singh: In 2N-dimensional phase space, ...

Associations between self-estimated and measured physical fitness among 40-year-old men and women.

Science.gov (United States)

Mikkelsson, L; Kaprio, J; Kautiainen, H; Kujala, U M; Nupponen, H

2005-10-01

The aim was to evaluate whether 40-year-old men and women are able to estimate their level of fitness compared with actual measured physical fitness. Twenty-nine men and 35 women first completed a questionnaire at home and then their physical fitness was measured at laboratory. The index of self-estimated physical fitness was calculated by summing up the scores of self-estimated endurance, strength, speed and flexibility. The index of self-estimated endurance was calculated by summing up the scores of self-estimated endurance and those of the self-estimated distance they could run, cycle, ski and walk. The index of measured physical fitness was calculated by summing up the z-scores of a submaximal bicycle ergometer test, ergojump tests (counter-movement jump and jumping in 15 s), a 30-s sit-up test, hand-grip tests and a sit-and-reach test. The correlation (Spearman) between the indices of self-estimated and measured physical fitness was 0.54 for both sexes, and that between self-estimated endurance and measured endurance was 0.53 for both sexes. Maximal oxygen uptake estimated based on submaximal ergometer test was higher among those with longer self-estimated distance of running, cycling, skiing and walking (P for linear trend ski or walk. However, in some individuals self-estimation of fitness is not in agreement with the results of fitness tests.

THE CONTRIBUTION OF 'RESTING' BODY MUSCLES TO THE SLOW COMPONENT OF PULMONARY OXYGEN UPTAKE DURING HIGH-INTENSITY CYCLING

Directory of Open Access Journals (Sweden)

Susan A. Ward

2012-12-01

Full Text Available Oxygen uptake (VO2 kinetics during moderate constant- workrate (WR exercise (>lactate-threshold (ӨL are well described as exponential. AboveӨL, these kinetics are more complex, consequent to the development of a delayed slow component (VO2sc, whose aetiology remains controversial. To assess the extent of the contribution to the VO2sc from arm muscles involved in postural stability during cycling, six healthy subjects completed an incremental cycle-ergometer test to the tolerable limit for estimation of ӨL and determination of peak VO2. They then completed two constant-WR tests at 90% of ӨL and two at 80% of ∆ (difference between ӨL and VO2peak. Gas exchange variables were derived breath-by-breath. Local oxygenation profiles of the vastus lateralis and biceps brachii muscles were assessed by near-infrared spectroscopy, with maximal voluntary contractions (MVC of the relevant muscles being performed post-exercise to provide a frame of reference for normalising the exercise-related oxygenation responses across subjects. Above supra-ӨL, VO2 rose in an exponential-like fashion ("phase 2, with a delayed VO2sc subsequently developing. This was accompanied by an increase in [reduced haemoglobin] relative to baseline (∆[Hb], which attained 79 ± 13 % (mean, SD of MVC maximum in vastus lateralis at end-exercise and 52 ± 27 % in biceps brachii. Biceps brachii ∆[Hb] was significantly correlated with VO2 throughout the slow phase. In contrast, for sub- L exercise, VO2 rose exponentially to reach a steady state with a more modest increase in vastus lateralis ∆[Hb] (30 ± 11 %; biceps brachii ∆[Hb] was minimally affected (8 ± 2 %. That the intramuscular O2 desaturation profile in biceps brachii was proportional to that for VO2sc during supra-ӨL cycle ergometry is consistent with additional stabilizing arm work contributing to the VO2sc

Profit maximization mitigates competition

DEFF Research Database (Denmark)

Dierker, Egbert; Grodal, Birgit

1996-01-01

We consider oligopolistic markets in which the notion of shareholders' utility is well-defined and compare the Bertrand-Nash equilibria in case of utility maximization with those under the usual profit maximization hypothesis. Our main result states that profit maximization leads to less price...... competition than utility maximization. Since profit maximization tends to raise prices, it may be regarded as beneficial for the owners as a whole. Moreover, if profit maximization is a good proxy for utility maximization, then there is no need for a general equilibrium analysis that takes the distribution...... of profits among consumers fully into account and partial equilibrium analysis suffices...

Implications of maximal Jarlskog invariant and maximal CP violation

International Nuclear Information System (INIS)

Rodriguez-Jauregui, E.; Universidad Nacional Autonoma de Mexico

2001-04-01

We argue here why CP violating phase Φ in the quark mixing matrix is maximal, that is, Φ=90 . In the Standard Model CP violation is related to the Jarlskog invariant J, which can be obtained from non commuting Hermitian mass matrices. In this article we derive the conditions to have Hermitian mass matrices which give maximal Jarlskog invariant J and maximal CP violating phase Φ. We find that all squared moduli of the quark mixing elements have a singular point when the CP violation phase Φ takes the value Φ=90 . This special feature of the Jarlskog invariant J and the quark mixing matrix is a clear and precise indication that CP violating Phase Φ is maximal in order to let nature treat democratically all of the quark mixing matrix moduli. (orig.)

Advertising and Business Cycle Fluctuations

OpenAIRE

Benedetto Molinari; Francesco Turino

2009-01-01

This paper provides new empirical evidence of quarterly U.S. aggregate advertising expenditures, showing that advertising has a well defined pattern over the Business Cycle. To understand this pattern we develop a general equilibrium model where targeted advertising increases the marginal utility of the advertised good. Advertising intensity is endogenously determined by profit maximizing firms. We embed this assumption into an otherwise standard model of business cycle with monopolistic comp...

Relation of oxygen uptake to work rate in prepubertal healthy children - reference for VO2/W-slope and effect on cardiorespiratory fitness assessment.

Science.gov (United States)

Tompuri, Tuomo; Lintu, Niina; Laitinen, Tomi; Lakka, Timo A

2017-08-09

Exercise testing by cycle ergometer allows to observe the interaction between oxygen uptake (VO 2 ) and workload (W), and VO 2 /W-slope can be used as a diagnostic tool. Respectively, peak oxygen uptake (VO 2 PEAK ) can be estimated by maximal workload. We aim to determine reference for VO 2 /W-slope among prepubertal children and define agreement between estimated and measured VO 2 PEAK . A total of 38 prepubertal children (20 girls) performed a maximal cycle ergometer test with respiratory gas analysis. VO 2 /W-slopes were computed using linear regression. Agreement analysis by Bland and Altman for estimated and measured VO 2 PEAK was carried out including limits of agreement (LA). Determinants for VO 2 /W-slopes and estimation bias were defined. VO2/W-slope was in both girls and boys ≥9·4 and did not change with exercise level, but the oxygen cost of exercise was higher among physically more active children. Estimated VO 2 PEAK had 6·4% coefficient of variation, and LA varied from 13% underestimation to 13% overestimation. Bias had a trend towards underestimation along lean mass proportional VO 2 PEAK . The primary determinant for estimation bias was VO2/W-slope (β = -0·65; PW-slope among healthy prepubertal children were similar to those published for adults and among adolescents. Estimated and measured VO 2 PEAK should not be considered to be interchangeable because of the variation in the relationship between VO 2 and W. On other hand, variation in the relationship between VO 2 and W enables that VO 2 /W-slope can be used as a diagnostic tool. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Maximizers versus satisficers

Directory of Open Access Journals (Sweden)

Andrew M. Parker

2007-12-01

Full Text Available Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007. Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al. (2002, we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decisions, more avoidance of decision making, and greater tendency to experience regret. Contrary to predictions, self-reported maximizers were more likely to report spontaneous decision making. However, the relationship between self-reported maximizing and worse life outcomes is largely unaffected by controls for measures of other decision-making styles, decision-making competence, and demographic variables.

Visual Impairment does not Limit Training Effects in Development of Aerobic and Anaerobic Capacity in Tandem Cyclists

Directory of Open Access Journals (Sweden)

Malwina Kamelska Anna

2015-12-01

Full Text Available The study aimed to investigate the differences in the effects of 7-month training on aerobic and anaerobic capacity in tandem cycling athletes with and without visual impairment. In this study, Polish elite (n=13 and sub-elite (n=13 visually impaired (VI (n=13; 40.8 ±12.8 years and properly sighted (PS (n=13; 36.7 ±12.2 years tandem-cycling athletes participated voluntarily in 7-month routine training. The following pre-/post-training measurements were conducted on separate days: maximal oxygen uptake (VO2max was estimated with age correction using the Physical Working Capacity test on a bicycle ergometer according to the Astrand-Ryhming method. Maximal power output (Pmax was evaluated using the Quebec test on a bicycle ergometer. At baseline, VO2max (47.8 ±14.1 vs 42.0 ±8.3 ml/kg/min, respectively and Pmax (11.5 ±1.5 vs 11.5 ±1.0 W/kg did not differ significantly between PS and VI cyclists. However, differences in aerobic capacity were considered as clinically significant. Two-way ANOVA revealed that after 7 month training, there were statistically significant increases in VO2max (p=0.003 and Pmax (p=0.009 among VI (VO2max, +9.1%; Pmax, +6.3% and PS (VO2max, +9.1%; Pmax, +11.7% cyclists, however, no time x visual impairment interaction effect was found (VO2max, p=0.467; Pmax, p=0.364. After training, VO2max (p=0.03, but not Pmax (p=0.13, was significantly greater in elite compared to sub-elite tandem cyclists. VI and PS tandem cyclists showed similar rates of improvement in VO2max and Pmax after 7-month training. VO2max was a significant determinant of success in tandem cycling. This is one of the first studies providing reference values for aerobic and anaerobic capacity in visually impaired cyclists.

Understanding the petrochemical cycle: Part 1

International Nuclear Information System (INIS)

Sedriks, W.

1994-01-01

Fitness in the hydrocarbon processing industry (HPI) arena involves understanding and coping with business cycles: supply and demand. This becomes increasingly more important as the industry globalizes and matures. Competitive-edge thinking needs to look hard at the forces that influence business cycles. Recognition of potential pitfalls is very important when considering: future capacity expansion, mergers and acquisitions, market departure, plant closure, potential product substitution, etc. Understanding pricing mechanisms and the workings of hockey-stick profitability profiles help HPI operators endure cycle downturns and prepare plants to maximize profits for the next upswing. The paper discusses characteristic trends, cycles in the hydrocarbon processing industry, current conditions, and mitigating cycle effects

Developing maximal neuromuscular power: Part 1--biological basis of maximal power production.

Science.gov (United States)

Cormie, Prue; McGuigan, Michael R; Newton, Robert U

2011-01-01

This series of reviews focuses on the most important neuromuscular function in many sport performances, the ability to generate maximal muscular power. Part 1 focuses on the factors that affect maximal power production, while part 2, which will follow in a forthcoming edition of Sports Medicine, explores the practical application of these findings by reviewing the scientific literature relevant to the development of training programmes that most effectively enhance maximal power production. The ability of the neuromuscular system to generate maximal power is affected by a range of interrelated factors. Maximal muscular power is defined and limited by the force-velocity relationship and affected by the length-tension relationship. The ability to generate maximal power is influenced by the type of muscle action involved and, in particular, the time available to develop force, storage and utilization of elastic energy, interactions of contractile and elastic elements, potentiation of contractile and elastic filaments as well as stretch reflexes. Furthermore, maximal power production is influenced by morphological factors including fibre type contribution to whole muscle area, muscle architectural features and tendon properties as well as neural factors including motor unit recruitment, firing frequency, synchronization and inter-muscular coordination. In addition, acute changes in the muscle environment (i.e. alterations resulting from fatigue, changes in hormone milieu and muscle temperature) impact the ability to generate maximal power. Resistance training has been shown to impact each of these neuromuscular factors in quite specific ways. Therefore, an understanding of the biological basis of maximal power production is essential for developing training programmes that effectively enhance maximal power production in the human.

Sprint performance and propulsion asymmetries on an ergometer in trained high- and low-point wheelchair rugby players.

Science.gov (United States)

Goosey-Tolfrey, V L; Vegter, R J K; Mason, B S; Paulson, T A W; Lenton, J P; van der Scheer, J W; van der Woude, L H V

2018-05-01

The purpose of this study was to examine the propulsion asymmetries of wheelchair athletes while sprinting on an instrumented, dual-roller ergometer system. Eighteen experienced wheelchair rugby players (8 low point (LP) (class ≤1.5) and 10 high point (HP) (class ≥2.0)) performed a 15-second sprint in their sports wheelchair on the instrumented ergometer. Asymmetry was defined as the difference in distance and power output (PO) between left and right sides when the best side reached 28 m. Propulsion techniques were quantified based on torque and velocity data. HP players covered an average 3 m further than the LP players (P = .002) and achieved faster sprint times than LP players (6.95 ± 0.89 vs 8.03 ± 0.68 seconds, P = .005) and at the time the best player finished (5.96 seconds). Higher peak POs (667 ± 108 vs 357 ± 78 W, P = .0001) and greater peak speeds that were also evident were for HP players (4.80 ± 0.71 vs 4.09 ± 0.45 m/s, P = .011). Greater asymmetries were found in HP players for distance (1.86 ± 1.43 vs 0.70 ± 0.65 m, P = .016), absolute peak PO (P = .049), and speed (0.35 ± 0.25 vs 0.11 ± 0.10 m/s, P = .009). Although HP players had faster sprint times over 28 m (achieved by a higher PO), high standard deviations show the heterogeneity within the two groups (eg, some LP players were better than HP players). Quantification of asymmetries is important not only for classifiers but also for sports practitioners wishing to improve performance as they could be addressed through training and/or wheelchair configuration. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of caffeine on maximal oxygen uptake in wheelchair rugby players: A randomized, placebo-controlled, double-blind study

Directory of Open Access Journals (Sweden)

Iva Klimešová

2017-03-01

Full Text Available Background: The positive effects of caffeine supplementation on strength-power and endurance performance in healthy athletes have been demonstrated in many studies. A possible mechanism for its ergogenic effect relates to its influence on the central nervous system. Post-traumatic complications in cervical spinal cord injury affect almost all body systems including the nervous system. For this reason, we expect that caffeine will have a different effect of performance in the group of athletes with spinal cord injuries. Objective: To examine the effects of caffeine supplementation on maximal aerobic power in elite wheelchair rugby players. Methods: Seven elite male wheelchair rugby players with complete cervical-level SCI (C4-Th1 were recruited (mean age: 28 ± 5.42 years; mean body mass index: 26 ± 2.84 kg/m2. The effect of caffeine was assessed by an incremental arm ergometer test until volitional exhaustion. The maximal oxygen uptake (VO2max/kg, maximum power (W max/kg, peak heart rate (HR peak, and intensity of perceived exertion (RPE were measured. Participants performed the test twice with a two-week washout period. One hour before each exercise test subjects ingested a capsule of placebo or caffeine (3 mg per kg of body weight. The tests were applied in a double-blind, randomized, repeated-measures, and cross-over design. Wheelchair rugby players were chosen because of the expected high homogeneity of participants - in terms of the type and degree of disability, gender, and age of the players. Results: The monitored parameters were not significantly influenced by caffeine intervention as compared to placebo: VO2max/kg (p = .40, W max/kg (p = .34, HR peak (p = .50 and RPE (p = .50. Conclusions: The current findings suggest that a caffeine dose of 3 mg/kg body mass does not improve oxygen uptake and maximal power in elite wheelchair rugby players.

201Tl in myocardial diagnosis: studies on the influence of dipyridamole, dobutamine ergometer exercise and background subtraction on the 201Tl myocadial scintiscam

International Nuclear Information System (INIS)

Seiderer, M.

1979-01-01

Changes in 201 Tl myocardial scintiscans upon administration of dipyridamole or dobutamine and upon ergometer exercise relative to scintiscans at rest were investigated as well as the influence of myocardial background subtraction on scintiscan quality and information. A total of 90 201 Tl examinations were carried out in 59 patients. 18 patients had no myocardial disease, 30 patients had a coronary disease, 5 patients suffered from cardiomyopathy and 6 from left ventricular hypertrophy. The findings are discussed in detail. (orig.) [de

Metabolic Engineering of TCA Cycle for Production of Chemicals

NARCIS (Netherlands)

Vuoristo, K.S.; Mars, A.E.; Sanders, J.P.M.; Eggink, G.; Weusthuis, R.A.

2016-01-01

The tricarboxylic acid (TCA) cycle has been used for decades in the microbial production of chemicals such as citrate, L-glutamate, and succinate. Maximizing yield is key for cost-competitive production. However, for most TCA cycle products, the maximum pathway yield is lower than the theoretical

Maximizers versus satisficers

OpenAIRE

Andrew M. Parker; Wandi Bruine de Bruin; Baruch Fischhoff

2007-01-01

Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007). Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al. (2002), we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decisions...

Jump ergometer in sport performance testing Výskokový ergometr v diagnostice sportovní výkonnosti

Directory of Open Access Journals (Sweden)

Dušan Hamar

2005-02-01

Full Text Available The papers deals with the application of the jump ergometer in the evaluation of neuromuscular performance. Altogether 288 athletes of different sport specializations (mean age 18.9 ± 6.4 years, height 172.2 ± 4.3 cm, and weight 62.4 ± 4.9 kg underwent various tests on the jump ergometer, such as 10-, 60-, and 90-second repeated jumps, squat and countermovement jumps without and with an additional load, and drop jumps from different heights with and without bending the knees. The diagnostic system FiTRO Jumper consisting of a special contact switch mattress connected by means of an interface to a computer was used. Jump parameters (power in the active phase of take off and height of the jump were calculated from the flight and contact times. Results showed that the system may be applied for the assessment of explosive power of the lower extremities, strength endurance of the lower extremities, utilization of the stretch shortening cycle, distribution of fast twitch fibers, optimal drop jump height for plyometric training, and training effects, namely in sports such as basketball, volleyball, soccer, tennis, gymnastics, rock and roll, figure skating, track and field, ski jumping, weight lifting, etc. Práce poukazuje na možnosti uplatnění výskokového ergometru při posuzovaní odrazových schopností dolních končetin. Celkem 288 sportovců s různou specializací (průměrný věk 18,9 ± 6,4 let, výška 172,2 ± 4,3 cm, hmotnost 62,4 ± 4,9 kg absolvovalo testy na výskokovém ergometru, a to 10, 60 a 90sekundový test opakovaných snožných výskoků, výskoky bez a s protipohybem s hmotností vlastního těla, resp. s dodatečnou váhou, jakož i seskoky z různych výšek do rovných, resp. pokrčených dolních končetin. Parametry odrazových schopností (výkon v aktivní fázi odrazu a výška výskoku byly registrovány pomocí diagnostického systému FiTRO Jumper sestávajícího z odrazové doby napojené prost

Design and optimization of air bottoming cycles for waste heat recovery in off-shore platforms

International Nuclear Information System (INIS)

Pierobon, Leonardo; Haglind, Fredrik

2014-01-01

Highlights: • Theory of power maximization used to design an air bottoming cycle. • Theory of power maximization extended by a multi-objective optimization method. • Three objective functions considered: net power output, recuperator volume and net present value. • Comparison between the theory of power maximization and the multi-objective optimization method. • Case study: a methodology applied to recover exhaust heat on off-shore platforms. - Abstract: This paper aims at comparing two methodologies to design an air bottoming cycle recovering the waste heat from the power generation system on the Draugen off-shore oil and gas platform. Firstly, the design is determined using the theory of the power maximization. Subsequently, the multi-objective optimization approach is employed to maximize the economic revenue, the compactness and the power production of the air bottoming cycle. The system compactness is assessed by introducing a detailed model of the shell and tube recuperator and including geometric quantities in the set of optimization variables. Findings indicate that using the power production, the volume of the recuperator and the net present value as objective functions the optimal pressure ratio (2.52) and the exhaust gas temperature (178.8 °C) differ from the values (2.80 and 145.5 °C) calculated using the theory of the power maximization. The highest net present value (2.8 M$) is found for a volume of the recuperator of 128 m 3 . Thus, it can be concluded that the multi-objective optimization approach enables extending the theory of power maximization bridging the gap between a mere optimization of the thermodynamic cycle and the practical feasibility of a power generation system

Adapted low intensity ergometer aerobic training for early and severely impaired stroke survivors: a pilot randomized controlled trial to explore its feasibility and efficacy.

Science.gov (United States)

Wang, Zun; Wang, Lei; Fan, Hongjuan; Jiang, Wenjun; Wang, Sheng; Gu, Zhaohua; Wang, Tong

2014-09-01

[Purpose] To evaluate the feasibility and efficacy of adapted low intensity ergometer aerobic training for early and severely impaired stroke survivors. [Subjects] The subjects were forty-eight early stroke survivors. [Methods] Eligible subjects were recruited and randomly assigned to an experimental group and a control group. Both groups participated in comprehensive rehabilitation training. Low intensity aerobic training was only performed by the experimental group. Outcome measures were the Fugl-Meyer motor score, Barthel index, exercise test time, peak heart rate, plasma glucose level and serum lipid profiles. [Results] Patients in the experimental group finished 88.6% of the total aerobic training sessions prescribed. In compliant participants (adherence≥80%), aerobic training significantly improved the Barthel index (from 40.1±21.1 to 79.2±14.2), Fugl-Meyer motor score (from 26.4±19.4 to 45.4±12.7), exercise test time (from 12.2±3.62 min to 13.9±3.6 min), 2-hour glucose level (from 9.22±1.16 mmol/L to 7.21±1.36 mmol/L) and homeostasis model of assessment for insulin resistence index (from 1.72±1.01 to 1.28±0.88). [Conclusion] Preliminary findings suggest that early and severely impaired stroke patients may benefit from low intensity ergometer aerobic training.

Effect of different cycling frequencies during incremental exercise on the venous plasma potassium concentration in humans.

Science.gov (United States)

Zoladz, J A; Duda, K; Majerczak, J; Thor, P

2002-01-01

The effect of different muscle shortening velocity was studied during cycling at a pedalling rate of 60 and 120 rev.min(-1) on the [K+]v in humans. Twenty-one healthy young men aged 22.5+/-2.2 years, body mass 72.7+/-6.4 kg, VO2 max 3.720+/-0.426 l. min(-1), performed an incremental exercise test until exhaustion. The power output increased by 30 W every 3 min, using an electrically controlled ergometer Ergoline 800 S (see Zoladz et al. J. Physiol. 488: 211-217, 1995). The test was performed twice: once at a cycling frequency of 60 rev.min(-1) (test A) and a few days later at a frequency of 120 rev. min(-1) (test B). At rest and at the end of each step (i.e. the last 15 s) antecubital venous blood samples for [K+]p were taken. Gas exchange variables were measured continuously (breath-by-breath) using Oxycon Champion Jaeger. The pre-exercise [K+]v in both tests was not significantly different amounting to 4.24+/-0.36 mmol.l(-1) in test A, and 4.37+/-0.45 mmol.l(-1) in test B. However, the [K+]p during cycling at 120 rev. min(-1) was significantly higher (p<0.001, ANOVA for repeated measurements) at each power output when compared to cycling at 60 rev.min(-1). The maximal power output reached 293+/-31 W in test A which was significantly higher (p<0.001) than in test B, which amounted to 223+/-40 W. The VO2max values in both tests reached 3.720+/-0.426 l. min(-1) vs 3.777+/-0.514 l. min(-1). These values were not significantly different. When the [K+]v was measured during incremental cycling exercise, a linear increase in [K+]v was observed in both tests. However, a significant (p<0.05) upward shift in the [K+]v and a % VO2max relationship was detected during cycling at 120 rev.min(-1). The [K+]v measured at the VO2max level in tests A and B amounted to 6.00+/-0.47 mmol.l-1 vs 6.04+/-0.41 mmol.l-1, respectively. This difference was not significant. It may thus be concluded that: a) generation of the same external mechanical power output during cycling at a pedalling

Entropy maximization

Indian Academy of Sciences (India)

Abstract. It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf f that satisfy. ∫ fhi dμ = λi for i = 1, 2,...,...k the maximizer of entropy is an f0 that is pro- portional to exp(. ∑ ci hi ) for some choice of ci . An extension of this to a continuum of.

Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise.

Science.gov (United States)

Yan, Huimin; Ranadive, Sushant M; Heffernan, Kevin S; Lane, Abbi D; Kappus, Rebecca M; Cook, Marc D; Wu, Pei-Tzu; Sun, Peng; Harvey, Idethia S; Woods, Jeffrey A; Wilund, Kenneth R; Fernhall, Bo

2014-01-01

African-American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian-American (CA) men. Women have greater age-associated increases in arterial stiffness and AIx than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and after an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men, and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest and 15 and 30 min after an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness was increased in AA subjects but not in CA subjects (P < 0.05) after an acute bout of maximal cycling exercise, after controlling for body mass index. Aortic BP decreased after exercise in CA subjects but not in AA subjects (P < 0.05). Women exhibited greater reductions in AIx after maximal aerobic exercise compared with men (P < 0.05). In conclusion, race and sex impact vascular and central hemodynamic responses to exercise. Young AA and CA subjects exhibited differential responses in central stiffness and central BP after acute maximal exercise. Premenopausal women had greater augmented pressure at rest and after maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms.

Entropy Maximization

Indian Academy of Sciences (India)

It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf that satisfy ∫ f h i d = i for i = 1 , 2 , … , … k the maximizer of entropy is an f 0 that is proportional to exp ⁡ ( ∑ c i h i ) for some choice of c i . An extension of this to a continuum of ...

Daily physical activity related to aerobic fitness and body fat in an urban sample of children

DEFF Research Database (Denmark)

Dencker, M; Thorsson, O; Karlsson, M K

2008-01-01

This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8-11 years. A cross-sectional study of 225 children aged 7.9-11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual......-energy x-ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days...... and daily accumulation of moderate-to-vigorous and vigorous activity was calculated. Significant relationships (Pfitness (r=0.38), whereas moderate-to-vigorous activity displayed weaker relationships...

Aerobic fitness after JDM--a long-term follow-up study

DEFF Research Database (Denmark)

Mathiesen, Pernille R; Orngreen, Mette C; Vissing, John

2013-01-01

Objectives. It has previously been shown that patients with active JDM have decreased aerobic fitness; however, it is not known whether these patients regain their physical fitness after recovery. The objective of this study was to investigate the long-term outcome of aerobic fitness in patients...... with JDM. We hypothesized that fitness (VO(2max)) is reduced compared with healthy controls in the years after active JDM.Methods. A maximal exercise test was performed using a cycle ergometer. Results were compared with those of sex- and age-matched healthy controls.Results. A total of 36 patients...... year of active disease, VO(2max) was reduced by 0.85 ml/min/kg on average (P fitness. This impairment is directly related to the duration of active disease....

Effect of anaerobic bout using wingate cycle ergometer on pressure pain threshold in normal individuals

Directory of Open Access Journals (Sweden)

Ajit Dabholkar

2017-01-01

Full Text Available Introduction: Published studies reveal that incremental graded and short term anaerobic exercise lead to an increase in beta-endorphin levels, the extent correlating with the lactate concentration. Beta- endorphin can be released into the circulation from the pituitary gland or can project into areas of the brain through nerve fibers. Exercise of sufficient intensity and duration has been demonstrated to increase circulating Beta-endorphin levels. Thus, our study investigates the effect of anaerobic activity on pressure pain threshold (PPT in normal individuals. Materials and Methods: Normal individuals (N = 30 between the age group of 20-30 years were recruited for this study. The subjects performed an anaerobic bout on Monark Wingate cycle egometer. A pre and post assessment of PPT was evaluated. Data Analysis: Graphpad Instat 3 software program was used for statistical analysis. A paired't' test was done to analyse the level of statistical significance between the pre and post PPT. Results: Study revealed that post anaerobic bout there was statistical significant difference between pre and post PPT in quadriceps, Mean 14.41,95% CI[12.95,15.87], Mean 16.73,95% CI[15.06,18.40] & (P value 0.0411 and gastrocnemius,Mean 13.56, 95% CI[12.18,14.93], Mean 15.55,95% CI[13.94,17.16] & (P value <0.0001. Conclusion: The study emphasizes the influence of pain modulation after an anaerobic bout.

Mechanically braked elliptical Wingate test: modification considerations, load optimization, and reliability.

Science.gov (United States)

Ozkaya, Ozgur; Colakoglu, Muzaffer; Kuzucu, Erinc O; Yildiztepe, Engin

2012-05-01

The 30-second, all-out Wingate test evaluates anaerobic performance using an upper or lower body cycle ergometer (cycle Wingate test). A recent study showed that using a modified electromagnetically braked elliptical trainer for Wingate testing (EWT) leads to greater power outcomes because of larger muscle group recruitment. The main purpose of this study was to modify an elliptical trainer using an easily understandable mechanical brake system instead of an electromagnetically braked modification. Our secondary aim was to determine a proper test load for the EWT to reveal the most efficient anaerobic test outcomes such as peak power (PP), average power (AP), minimum power (MP), power drop (PD), and fatigue index ratio (FI%) and to evaluate the retest reliability of the selected test load. Delta lactate responses (ΔLa) were also analyzed to confirm all the anaerobic performance of the athletes. Thirty healthy and well-trained male university athletes were selected to participate in the study. By analysis of variance, an 18% body mass workload yielded significantly greater test outcomes (PP = 19.5 ± 2.4 W·kg, AP = 13.7 ± 1.7 W·kg, PD = 27.9 ± 5 W·s, FI% = 58.4 ± 3.3%, and ΔLa = 15.4 ± 1.7 mM) than the other (12-24% body mass) tested loads (p braked modification of an elliptical trainer successfully estimated anaerobic power and capacity. A workload of 18% body mass was optimal for measuring maximal and reliable anaerobic power outcomes. Anaerobic testing using an EWT may be more useful to athletes and coaches than traditional cycle ergometers because a greater proportion of muscle groups are worked during exercise on an elliptical trainer.

Maximally incompatible quantum observables

Energy Technology Data Exchange (ETDEWEB)

Heinosaari, Teiko, E-mail: teiko.heinosaari@utu.fi [Turku Centre for Quantum Physics, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Schultz, Jussi, E-mail: jussi.schultz@gmail.com [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Toigo, Alessandro, E-mail: alessandro.toigo@polimi.it [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Ziman, Mario, E-mail: ziman@savba.sk [RCQI, Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 84511 Bratislava (Slovakia); Faculty of Informatics, Masaryk University, Botanická 68a, 60200 Brno (Czech Republic)

2014-05-01

The existence of maximally incompatible quantum observables in the sense of a minimal joint measurability region is investigated. Employing the universal quantum cloning device it is argued that only infinite dimensional quantum systems can accommodate maximal incompatibility. It is then shown that two of the most common pairs of complementary observables (position and momentum; number and phase) are maximally incompatible.

Maximally incompatible quantum observables

International Nuclear Information System (INIS)

Heinosaari, Teiko; Schultz, Jussi; Toigo, Alessandro; Ziman, Mario

2014-01-01

The existence of maximally incompatible quantum observables in the sense of a minimal joint measurability region is investigated. Employing the universal quantum cloning device it is argued that only infinite dimensional quantum systems can accommodate maximal incompatibility. It is then shown that two of the most common pairs of complementary observables (position and momentum; number and phase) are maximally incompatible.

Feasibility of virtual reality augmented cycling for health promotion of people poststroke.

Science.gov (United States)

Deutsch, Judith E; Myslinski, Mary Jane; Kafri, Michal; Ranky, Richard; Sivak, Mark; Mavroidis, Constantinos; Lewis, Jeffrey A

2013-09-01

A virtual reality (VR) augmented cycling kit (VRACK) was developed to address motor control and fitness deficits of individuals with chronic stroke. In this article, we report on the safety, feasibility, and efficacy of using the VR augmented cycling kit to improve cardiorespiratory (CR) fitness of individuals in the chronic phase poststroke. Four individuals with chronic stroke (47-65 years old and ≥3 years poststroke), with residual lower extremity impairments (Fugl-Meyer 24-26/34), who were limited community ambulators (gait speed range 0.56-1.1 m/s) participated in this study. Safety was defined as the absence of adverse events. Feasibility was measured using attendance, total exercise time, and "involvement" measured with the presence questionnaire (PQ). Efficacy of CR fitness was evaluated using a submaximal bicycle ergometer test before and after an 8-week training program. The intervention was safe and feasible with participants having 1 adverse event, 100% adherence, achieving between 90 and 125 minutes of cycling each week, and a mean PQ score of 39 (SD 3.3). There was a statistically significant (13%; P = 0.035) improvement in peak VO(2), with a range of 6% to 24.5%. For these individuals, poststroke, VR augmented cycling, using their heart rate to set their avatar's speed, fostered training of sufficient duration and intensity to promote CR fitness. In addition, there was a transfer of training from the bicycle to walking endurance. VR augmented cycling may be an addition to the therapist's tools for concurrent training of mobility and health promotion of individuals poststroke.

Systolisk blodtryk i hvile og under submaksimal og maksimal arbejdsbelastning på ergometercykel. Værdien af automatisk og auskultatorisk bestemmelse

DEFF Research Database (Denmark)

Petersen, J R; Drabaek, H; Mehlsen, J

1993-01-01

Fifteen normal subjects participated in this comparison of systolic blood pressure measurement determined both automatically (AU) with the Kivex Ergometrics 900 and by the standard auscultatorically method (AM). Maximal exercise, was achieved by work performed on an electronically braked ergomete...

Maximal combustion temperature estimation

International Nuclear Information System (INIS)

Golodova, E; Shchepakina, E

2006-01-01

This work is concerned with the phenomenon of delayed loss of stability and the estimation of the maximal temperature of safe combustion. Using the qualitative theory of singular perturbations and canard techniques we determine the maximal temperature on the trajectories located in the transition region between the slow combustion regime and the explosive one. This approach is used to estimate the maximal temperature of safe combustion in multi-phase combustion models

Effects of caffeine on neuromuscular fatigue and performance during high-intensity cycling exercise in moderate hypoxia.

Science.gov (United States)

Smirmaul, Bruno P C; de Moraes, Antonio Carlos; Angius, Luca; Marcora, Samuele M

2017-01-01

To investigate the effects of caffeine on performance, neuromuscular fatigue and perception of effort during high-intensity cycling exercise in moderate hypoxia. Seven adult male participants firstly underwent an incremental exercise test on a cycle ergometer in conditions of acute normobaric hypoxia (fraction inspired oxygen = 0.15) to establish peak power output (PPO). In the following two visits, they performed a time to exhaustion test (78 ± 3% PPO) in the same hypoxic conditions after caffeine ingestion (4 mg kg -1 ) and one after placebo ingestion in a double-blind, randomized, counterbalanced cross-over design. Caffeine significantly improved time to exhaustion by 12%. A significant decrease in subjective fatigue was found after caffeine consumption. Perception of effort and surface electromyographic signal amplitude of the vastus lateralis were lower and heart rate was higher in the caffeine condition when compared to placebo. However, caffeine did not reduce the peripheral and central fatigue induced by high-intensity cycling exercise in moderate hypoxia. The caffeine-induced improvement in time to exhaustion during high-intensity cycling exercise in moderate hypoxia seems to be mediated by a reduction in perception of effort, which occurs despite no reduction in neuromuscular fatigue.

Dietary acid load and renal function have varying effects on blood acid-base status and exercise performance across age and sex.

Science.gov (United States)

Hietavala, Enni-Maria; Stout, Jeffrey R; Frassetto, Lynda A; Puurtinen, Risto; Pitkänen, Hannu; Selänne, Harri; Suominen, Harri; Mero, Antti A

2017-12-01

Diet composition influences acid-base status of the body. This may become more relevant as renal functional capacity declines with aging. We examined the effects of low (LD) versus high dietary acid load (HD) on blood acid-base status and exercise performance. Participants included 22 adolescents, 33 young adults (YA), and 33 elderly (EL), who followed a 7-day LD and HD in a randomized order. At the end of both diet periods the subjects performed a cycle ergometer test (3 × 10 min at 35%, 55%, 75%, and (except EL) until exhaustion at 100% of maximal oxygen uptake). At the beginning of and after the diet periods, blood samples were collected at rest and after all workloads. Oxygen uptake, respiratory exchange ratio (RER), and heart rate (HR) were monitored during cycling. In YA and EL, bicarbonate (HCO 3 - ) and base excess (BE) decreased over the HD period, and HCO 3 - , BE, and pH were lower at rest after HD compared with LD. In YA and EL women, HCO 3 - and BE were lower at submaximal workloads after HD compared with LD. In YA women, the maximal workload was 19% shorter and maximal oxygen uptake, RER, and HR were lower after HD compared with LD. Our data uniquely suggests that better renal function is associated with higher availability of bases, which may diminish exercise-induced acidosis and improve maximal aerobic performance. Differences in glomerular filtration rate between the subject groups likely explains the larger effects of dietary acid load in the elderly compared with younger subjects and in women compared with men.

Validity of single-cycle objective functions for multicycle reload design optimization

International Nuclear Information System (INIS)

Kropaczek, D.J.; McElroy, J.; Turinsky, P.J.

1993-01-01

Beyond the equilibrium cycle scoping calculations used for determining numbers of feed assemblies and enrichment estimates, multicycle reload design currently consists of stagewise optimization of single-cycle core loading patterns, typically extending over a short-term planning horizon of perhaps three reload cycles. Particularly in transition cycles, however, optimizing a loading pattern over a single cycle for a stated objective, such as minimum core leakage, may have an adverse impact on subsequent cycles. The penalties paid may be in the form of reduced thermal margin or an increase in feed enrichment due to insufficient reactivity carryover from the open-quotes optimizedclose quotes cycle. In view of current practices, a study was performed that examined the behavior of the loading pattern as a function of the objective functions selected as implemented in the stagewise optimization of single-cycle core loading patterns from initial transition cycle through equilibrium using the FORMOSA-P code. The objective functions studied were region average discharge burnup maximization (with enrichment search) and feed enrichment minimization. It is noted at the beginning that the maximization of region average discharge has no meaning for the equilibrium cycle because region average discharge burnup is explicitly set by the feed size and cycle length independent of the loading pattern. In the nonequilibrium cycle, however, it was reasoned that this objective would provide the maximum reactivity carryover throughout the transition and thus have a direct effect on minimizing the multicycle levelized fuel cost

On the configuration of supercapacitors for maximizing electrochemical performance.

Science.gov (United States)

Zhang, Jintao; Zhao, X S

2012-05-01

Supercapacitors, which are attracting rapidly growing interest from both academia and industry, are important energy-storage devices for acquiring sustainable energy. Recent years have seen a number of significant breakthroughs in the research and development of supercapacitors. The emergence of innovative electrode materials (e.g., graphene) has clearly provided great opportunities for advancing the science in the field of electrochemical energy storage. Conversely, smart configurations of electrode materials and new designs of supercapacitor devices have, in many cases, boosted the electrochemical performance of the materials. We attempt to summarize recent research progress towards the design and configuration of electrode materials to maximize supercapacitor performance in terms of energy density, power density, and cycle stability. With a brief description of the structure, energy-storage mechanism, and electrode configuration of supercapacitor devices, the design and configuration of symmetric supercapacitors are discussed, followed by that of asymmetric and hybrid supercapacitors. Emphasis is placed on the rational design and configuration of supercapacitor electrodes to maximize the electrochemical performance of the device. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Maximizing Efficiency in Two-step Solar-thermochemical Fuel Production

Energy Technology Data Exchange (ETDEWEB)

Ermanoski, I. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

2015-05-01

Widespread solar fuel production depends on its economic viability, largely driven by the solar-to-fuel conversion efficiency. In this paper, the material and energy requirements in two-step solar-thermochemical cycles are considered.The need for advanced redox active materials is demonstrated, by considering the oxide mass flow requirements at a large scale. Two approaches are also identified for maximizing the efficiency: optimizing reaction temperatures, and minimizing the pressure in the thermal reduction step by staged thermal reduction. The results show that each approach individually, and especially the two in conjunction, result in significant efficiency gains.

Single and combined effects of beetroot juice and caffeine supplementation on cycling time trial performance.

Science.gov (United States)

Lane, Stephen C; Hawley, John A; Desbrow, Ben; Jones, Andrew M; Blackwell, James R; Ross, Megan L; Zemski, Adam J; Burke, Louise M

2014-09-01

Both caffeine and beetroot juice have ergogenic effects on endurance cycling performance. We investigated whether there is an additive effect of these supplements on the performance of a cycling time trial (TT) simulating the 2012 London Olympic Games course. Twelve male and 12 female competitive cyclists each completed 4 experimental trials in a double-blind Latin square design. Trials were undertaken with a caffeinated gum (CAFF) (3 mg·kg(-1) body mass (BM), 40 min prior to the TT), concentrated beetroot juice supplementation (BJ) (8.4 mmol of nitrate (NO3(-)), 2 h prior to the TT), caffeine plus beetroot juice (CAFF+BJ), or a control (CONT). Subjects completed the TT (females: 29.35 km; males: 43.83 km) on a laboratory cycle ergometer under conditions of best practice nutrition: following a carbohydrate-rich pre-event meal, with the ingestion of a carbohydrate-electrolyte drink and regular oral carbohydrate contact during the TT. Compared with CONT, power output was significantly enhanced after CAFF+BJ and CAFF (3.0% and 3.9%, respectively, p caffeine (-0.9%, p = 0.4 compared with CAFF). We conclude that caffeine (3 mg·kg(-1) BM) administered in the form of a caffeinated gum increased cycling TT performance lasting ∼50-60 min by ∼3%-4% in both males and females. Beetroot juice supplementation was not ergogenic under the conditions of this study.

Maximal COX-2 and ppRb expression in neurons occurs during early Braak stages prior to the maximal activation of astrocytes and microglia in Alzheimer's disease

Directory of Open Access Journals (Sweden)

Arendt Thomas

2005-11-01

Full Text Available Abstract Neuronal expression of cyclooxygenase-2 (COX-2 and cell cycle proteins is suggested to contribute to neurodegeneration during Alzheimer's disease (AD. The stimulus that induces COX-2 and cell cycle protein expression in AD is still elusive. Activated glia cells are shown to secrete substances that can induce expression of COX-2 and cell cycle proteins in vitro. Using post mortem brain tissue we have investigated whether activation of microglia and astrocytes in AD brain can be correlated with the expression of COX-2 and phosphorylated retinoblastoma protein (ppRb. The highest levels of neuronal COX-2 and ppRb immunoreactivity are observed in the first stages of AD pathology (Braak 0–II, Braak A. No significant difference in COX-2 or ppRb neuronal immunoreactivity is observed between Braak stage 0 and later Braak stages for neurofibrillary changes or amyloid plaques. The mean number of COX-2 or ppRb immunoreactive neurons is significantly decreased in Braak stage C compared to Braak stage A for amyloid deposits. Immunoreactivity for glial markers KP1, CR3/43 and GFAP appears in the later Braak stages and is significantly increased in Braak stage V-VI compared to Braak stage 0 for neurofibrillary changes. In addition, a significant negative correlation is observed between the presence of KP1, CR3/43 and GFAP immunoreactivity and the presence of neuronal immunoreactivity for COX-2 and ppRb. These data show that maximal COX-2 and ppRb immunoreactivity in neurons occurs during early Braak stages prior to the maximal activation of astrocytes and microglia. In contrast to in vitro studies, post mortem data do not support a causal relation between the activation of microglia and astrocytes and the expression of neuronal COX-2 and ppRb in the pathological cascade of AD.

Sudomotor Function as a Tool for Cardiorespiratory Fitness Level Evaluation: Comparison with Maximal Exercise Capacity

Directory of Open Access Journals (Sweden)

Anu Raisanen

2014-05-01

Full Text Available Physical inactivity is a modifiable risk factor for cardiovascular (CV and metabolic disorders. VO2max is the best method to assess cardio-respiratory fitness level but it is poorly adopted in clinical practice. Sudomotor dysfunction may develop early in metabolic diseases. This study aimed at comparing established CV risk evaluation techniques with SUDOSCAN; a quick and non-invasive method to assess sudomotor function. A questionnaire was filled-in; physical examination and VO2max estimation using a maximal test on a bicycle ergometer were performed on active Finish workers. Hand and foot electrochemical skin conductance (ESC were measured to assess sudomotor function. Subjects with the lowest fitness level were involved in a 12 month training program with recording of their weekly physical activity and a final fitness level evaluation. Significant differences in BMI; waist and body fat were seen according to SUDOSCAN risk score classification. Correlation between the risk score and estimated VO2max was r = −0.57, p < 0.0001 for women and −0.48, p < 0.0001 for men. A significant increase in estimated VO2max, in hand and foot ESC and in risk score was observed after lifestyle intervention and was more important in subjects with the highest weekly activity. SUDOSCAN could be used to assess cardio-metabolic disease risk status in a working population and to follow individual lifestyle interventions.

AUC-Maximizing Ensembles through Metalearning.

Science.gov (United States)

LeDell, Erin; van der Laan, Mark J; Petersen, Maya

2016-05-01

Area Under the ROC Curve (AUC) is often used to measure the performance of an estimator in binary classification problems. An AUC-maximizing classifier can have significant advantages in cases where ranking correctness is valued or if the outcome is rare. In a Super Learner ensemble, maximization of the AUC can be achieved by the use of an AUC-maximining metalearning algorithm. We discuss an implementation of an AUC-maximization technique that is formulated as a nonlinear optimization problem. We also evaluate the effectiveness of a large number of different nonlinear optimization algorithms to maximize the cross-validated AUC of the ensemble fit. The results provide evidence that AUC-maximizing metalearners can, and often do, out-perform non-AUC-maximizing metalearning methods, with respect to ensemble AUC. The results also demonstrate that as the level of imbalance in the training data increases, the Super Learner ensemble outperforms the top base algorithm by a larger degree.

Can endurance training improve physical capacity and quality of life in young Fontan patients?

Science.gov (United States)

Hedlund, Eva R; Lundell, Bo; Söderström, Liselott; Sjöberg, Gunnar

2018-03-01

Children after Fontan palliation have reduced exercise capacity and quality of life. Our aim was to study whether endurance training could improve physical capacity and quality of life in Fontan patients. Fontan patients (n=30) and healthy age- and gender-matched control subjects (n=25) performed a 6-minute walk test at submaximal capacity and a maximal cycle ergometer test. Quality of life was assessed with Pediatric Quality of Life Inventory Version 4.0 questionnaires for children and parents. All tests were repeated after a 12-week endurance training programme and after 1 year. Patients had decreased submaximal and maximal exercise capacity (maximal oxygen uptake 35.0±5.1 ml/minute per·kg versus 43.7±8.4 ml/minute·per·kg, pquality of life score (70.9±9.9 versus 85.7±8.0, pimproved their submaximal exercise capacity in a 6-minute walk test (from 590.7±65.5 m to 611.8±70.9 m, pquality of life (pimprove maximal exercise capacity. At follow-up, submaximal exercise capacity had increased further and improved quality of life was sustained. The controls improved their maximal exercise capacity (pquality of life after training. At follow-up, improvement of maximal exercise capacity was sustained. We believe that an individualised endurance training programme for Fontan patients improves submaximal exercise capacity and quality of life in Fontan patients and the effect on quality of life appears to be long-lasting.

Life cycle management and assessment: approaches and visions towards sustainable manufacturing

DEFF Research Database (Denmark)

Westkämper, Engelbert; Alting, Leo; Arndt, Günther

2000-01-01

. The goal of this approach is to protect resources and maximize effectiveness by means of life cycle assessment, product data management, technical support and, last but not least, life cycle costing. This paper shows the existing approaches of LCM and discusses their prospects and further development....... concepts are required, new regulations have been passed or consumer values are changing, the differences between business areas are disappearing. Life cycle management (LCM) considers the product life cycle as a whole and optimizes the interaction of product design, manufacturing and life cycle activities...

Is CP violation maximal

International Nuclear Information System (INIS)

Gronau, M.

1984-01-01

Two ambiguities are noted in the definition of the concept of maximal CP violation. The phase convention ambiguity is overcome by introducing a CP violating phase in the quark mixing matrix U which is invariant under rephasing transformations. The second ambiguity, related to the parametrization of U, is resolved by finding a single empirically viable definition of maximal CP violation when assuming that U does not single out one generation. Considerable improvement in the calculation of nonleptonic weak amplitudes is required to test the conjecture of maximal CP violation. 21 references

Shareholder, stakeholder-owner or broad stakeholder maximization

OpenAIRE

Mygind, Niels

2004-01-01

With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating stakeholder-owner. Maximization of shareholder value is a special case of owner-maximization, and only under quite re-strictive assumptions shareholder maximization is larger or equal to stakeholder-owner...

Hand-Rim Forces and Gross Mechanical Efficiency in Asynchronous and Synchronous Wheelchair Propulsion : A Comparison

NARCIS (Netherlands)

Lenton, J. P.; Fowler, N.; Nicholson, G.; Tolfrey, K.; Goosey-Tolfrey, V.; van der Woude, Lucas

To compare the force application characteristics at various push frequencies of asynchronous (ASY) and synchronous (SYN) hand-rim propulsion, 8 able-bodied participants performed a separate sub-maximal exercise test on a wheelchair roller ergometer for each propulsion mode. Each test consisted of a

Ischemic Preconditioning of One Forearm Enhances Static and Dynamic Apnea

DEFF Research Database (Denmark)

Kjeld, Thomas; Rasmussen, Mads Reinholdt; Jattu, Timo

2014-01-01

INTRODUCTION: Ischemic preconditioning enhances ergometer cycling and swimming performance. We evaluated whether ischemic preconditioning of one forearm (four times for 5 min) also affects static breath hold and underwater swimming, whereas the effect of similar preconditioning on ergometer rowing...... preconditioning reduced the forearm oxygen saturation from 65% ± 7% to 19% ± 7% (mean ± SD; P right thigh.......05). CONCLUSIONS: We conclude that while the effect of ischemic preconditioning (of one forearm) on ergometer rowing was minimal, probably because of reduced muscle oxygenation during the warm-up, ischemic preconditioning does enhance both static and dynamic apnea, supporting that muscle ischemia is an important...

Reversible Carnot cycle outside a black hole

International Nuclear Information System (INIS)

Xi-Hao, Deng; Si-Jie, Gao

2009-01-01

A Carnot cycle outside a Schwarzschild black hole is investigated in detail. We propose a reversible Carnot cycle with a black hole being the cold reservoir. In our model, a Carnot engine operates between a hot reservoir with temperature T 1 and a black hole with Hawking temperature T H . By naturally extending the ordinary Carnot cycle to the black hole system, we show that the thermal efficiency for a reversible process can reach the maximal efficiency 1 – T H /T 1 . Consequently, black holes can be used to determine the thermodynamic temperature by means of the Carnot cycle. The role of the atmosphere around the black hole is discussed. We show that the thermal atmosphere provides a necessary mechanism to make the process reversible. (general)

Task-oriented maximally entangled states

International Nuclear Information System (INIS)

Agrawal, Pankaj; Pradhan, B

2010-01-01

We introduce the notion of a task-oriented maximally entangled state (TMES). This notion depends on the task for which a quantum state is used as the resource. TMESs are the states that can be used to carry out the task maximally. This concept may be more useful than that of a general maximally entangled state in the case of a multipartite system. We illustrate this idea by giving an operational definition of maximally entangled states on the basis of communication tasks of teleportation and superdense coding. We also give examples and a procedure to obtain such TMESs for n-qubit systems.

Detailed analysis of the effect of the turbine and compressor isentropic efficiency on the thermal and exergy efficiency of a Brayton cycle

Directory of Open Access Journals (Sweden)

Živić Marija

2014-01-01

Full Text Available Energy and exergy analysis of a Brayton cycle with an ideal gas is given. The irreversibility of the adiabatic processes in turbine and compressor is taken into account through their isentropic efficiencies. The net work per cycle, the thermal efficiency and the two exergy efficiencies are expressed as functions of the four dimensionless variables: the isentropic efficiencies of turbine and compressor, the pressure ratio, and the temperature ratio. It is shown that the maximal values of the net work per cycle, the thermal and the exergy efficiency are achieved when the isentropic efficiencies and temperature ratio are as high as possible, while the different values of pressure ratio that maximize the net work per cycle, the thermal and the exergy efficiencies exist. These pressure ratios increase with the increase of the temperature ratio and the isentropic efficiency of compressor and turbine. The increase of the turbine isentropic efficiency has a greater impact on the increase of the net work per cycle and the thermal efficiency of a Brayton cycle than the same increase of compressor isentropic efficiency. Finally, two goal functions are proposed for thermodynamic optimization of a Brayton cycle for given values of the temperature ratio and the compressor and turbine isentropic efficiencies. The first maximizes the sum of the net work per cycle and thermal efficiency while the second the net work per cycle and exergy efficiency. In both cases the optimal pressure ratio is closer to the pressure ratio that maximizes the net work per cycle.

FLOUTING MAXIMS IN INDONESIA LAWAK KLUB CONVERSATION

Directory of Open Access Journals (Sweden)

Rahmawati Sukmaningrum

2017-04-01

Full Text Available This study aims to identify the types of maxims flouted in the conversation in famous comedy show, Indonesia Lawak Club. Likewise, it also tries to reveal the speakers‘ intention of flouting the maxim in the conversation during the show. The writers use descriptive qualitative method in conducting this research. The data is taken from the dialogue of Indonesia Lawak club and then analyzed based on Grice‘s cooperative principles. The researchers read the dialogue‘s transcripts, identify the maxims, and interpret the data to find the speakers‘ intention for flouting the maxims in the communication. The results show that there are four types of maxims flouted in the dialogue. Those are maxim of quality (23%, maxim of quantity (11%, maxim of manner (31%, and maxim of relevance (35. Flouting the maxims in the conversations is intended to make the speakers feel uncomfortable with the conversation, show arrogances, show disagreement or agreement, and ridicule other speakers.

VIOLATION OF CONVERSATION MAXIM ON TV ADVERTISEMENTS

Directory of Open Access Journals (Sweden)

Desak Putu Eka Pratiwi

2015-07-01

Full Text Available Maxim is a principle that must be obeyed by all participants textually and interpersonally in order to have a smooth communication process. Conversation maxim is divided into four namely maxim of quality, maxim of quantity, maxim of relevance, and maxim of manner of speaking. Violation of the maxim may occur in a conversation in which the information the speaker has is not delivered well to his speaking partner. Violation of the maxim in a conversation will result in an awkward impression. The example of violation is the given information that is redundant, untrue, irrelevant, or convoluted. Advertisers often deliberately violate the maxim to create unique and controversial advertisements. This study aims to examine the violation of maxims in conversations of TV ads. The source of data in this research is food advertisements aired on TV media. Documentation and observation methods are applied to obtain qualitative data. The theory used in this study is a maxim theory proposed by Grice (1975. The results of the data analysis are presented with informal method. The results of this study show an interesting fact that the violation of maxim in a conversation found in the advertisement exactly makes the advertisements very attractive and have a high value.

Finding Maximal Quasiperiodicities in Strings

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Pedersen, Christian N. S.

2000-01-01

of length n in time O(n log n) and space O(n). Our algorithm uses the suffix tree as the fundamental data structure combined with efficient methods for merging and performing multiple searches in search trees. Besides finding all maximal quasiperiodic substrings, our algorithm also marks the nodes......Apostolico and Ehrenfeucht defined the notion of a maximal quasiperiodic substring and gave an algorithm that finds all maximal quasiperiodic substrings in a string of length n in time O(n log2 n). In this paper we give an algorithm that finds all maximal quasiperiodic substrings in a string...... in the suffix tree that have a superprimitive path-label....

The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint

Directory of Open Access Journals (Sweden)

Shaun M. Phillips, Scott Findlay, Mykolas Kavaliauskas, Marie Clare Grant

2014-06-01

Full Text Available The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD age: 23.1 (3.0 years, height: 1.83 (0.07 m, body mass (BM: 86.3 (13.5 kg completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg-1 BM resistance. Eight participants achieved a greater peak power output (PPO in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg-1, p 0.05. No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint.

Life cycle management and assessment: approaches and visions towards sustainable manufacturing

DEFF Research Database (Denmark)

Westkämper, Engelbert; Alting, Leo; Arndt, Günther

2001-01-01

and optimizes the interaction of product design, manufacturing and life cycle activities. The goal of this approach is to protect resources and maximize effectiveness by means of life cycle assessment, product data management, technical support and, last but not least, life cycle costing. This paper shows....... Economically successful business areas can also be explored. Whether new service concepts are required, new regulations have been passed or consumer values are changing, the differences between business areas are disappearing. Life cycle management (LCM) considers the product life cycle as a whole...... the existing approaches of LCM and discusses their prospects and further development....

Left ventricular atrioventricular plane displacement is preserved with lifelong endurance training and is the main determinant of maximal cardiac output

DEFF Research Database (Denmark)

Steding-Ehrenborg, Katarina; Boushel, Robert C; Calbet, José A

2015-01-01

subjects (29 ± 4 years) underwent cardiac MR. All subjects underwent maximal exercise testing and for elderly subjects maximal cardiac output during cycling was determined using dye dilution technique. RESULTS: Longitudinal and radial contribution to stroke volume did not differ between groups......BACKGROUND: Age-related decline in cardiac function can be prevented or postponed by lifelong endurance training. However, effects of normal ageing as well as of lifelong endurance exercise on longitudinal and radial contribution to stroke volume are unknown. The aim of this study was to determine...... groups for RVAVPD (P = 0.2). LVAVPD was an independent predictor of maximal cardiac output (R(2 = ) 0.61, P groups. However, how longitudinal pumping...

Effects of Black Hole Spin on the Limit-Cycle Behaviour of Accretion ...

Indian Academy of Sciences (India)

We present a spatially 1.5-dimensional, time-dependent numerical study of accretion disks around Kerr black holes. Our study focuses on the limit-cycle behavior of thermally unstable accretion disks. We find that maximal luminosity may be a more appropriate probe of black hole spin than the cycle duration and influence ...

Shareholder, stakeholder-owner or broad stakeholder maximization

DEFF Research Database (Denmark)

Mygind, Niels

2004-01-01

With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating...... including the shareholders of a company. Although it may be the ultimate goal for Corporate Social Responsibility to achieve this kind of maximization, broad stakeholder maximization is quite difficult to give a precise definition. There is no one-dimensional measure to add different stakeholder benefits...... not traded on the mar-ket, and therefore there is no possibility for practical application. Broad stakeholder maximization instead in practical applications becomes satisfying certain stakeholder demands, so that the practical application will be stakeholder-owner maximization un-der constraints defined...

On the maximal superalgebras of supersymmetric backgrounds

International Nuclear Information System (INIS)

Figueroa-O'Farrill, Jose; Hackett-Jones, Emily; Moutsopoulos, George; Simon, Joan

2009-01-01

In this paper we give a precise definition of the notion of a maximal superalgebra of certain types of supersymmetric supergravity backgrounds, including the Freund-Rubin backgrounds, and propose a geometric construction extending the well-known construction of its Killing superalgebra. We determine the structure of maximal Lie superalgebras and show that there is a finite number of isomorphism classes, all related via contractions from an orthosymplectic Lie superalgebra. We use the structure theory to show that maximally supersymmetric waves do not possess such a maximal superalgebra, but that the maximally supersymmetric Freund-Rubin backgrounds do. We perform the explicit geometric construction of the maximal superalgebra of AdS 4 X S 7 and find that it is isomorphic to osp(1|32). We propose an algebraic construction of the maximal superalgebra of any background asymptotic to AdS 4 X S 7 and we test this proposal by computing the maximal superalgebra of the M2-brane in its two maximally supersymmetric limits, finding agreement.

With age a lower individual breathing reserve is associated with a higher maximal heart rate.

Science.gov (United States)

Burtscher, Martin; Gatterer, Hannes; Faulhaber, Martin; Burtscher, Johannes

2018-01-01

Maximal heart rate (HRmax) is linearly declining with increasing age. Regular exercise training is supposed to partly prevent this decline, whereas sex and habitual physical activity do not. High exercise capacity is associated with a high cardiac output (HR x stroke volume) and high ventilatory requirements. Due to the close cardiorespiratory coupling, we hypothesized that the individual ventilatory response to maximal exercise might be associated with the age-related HRmax. Retrospective analyses have been conducted on the results of 129 consecutively performed routine cardiopulmonary exercise tests. The study sample comprised healthy subjects of both sexes of a broad range of age (20-86 years). Maximal values of power output, minute ventilation, oxygen uptake and heart rate were assessed by the use of incremental cycle spiroergometry. Linear multivariate regression analysis revealed that in addition to age the individual breathing reserve at maximal exercise was independently predictive for HRmax. A lower breathing reserve due to a high ventilatory demand and/or a low ventilatory capacity, which is more pronounced at a higher age, was associated with higher HRmax. Age explained the observed variance in HRmax by 72% and was improved to 83% when the variable "breathing reserve" was entered. The presented findings indicate an independent association between the breathing reserve at maximal exercise and maximal heart rate, i.e. a low individual breathing reserve is associated with a higher age-related HRmax. A deeper understanding of this association has to be investigated in a more physiological scenario. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioeconomic of profit maximization of red tilapia (Oreochromis sp.) culture using polynomial growth model

Science.gov (United States)

Wijayanto, D.; Kurohman, F.; Nugroho, RA

2018-03-01

The research purpose was to develop a model bioeconomic of profit maximization that can be applied to red tilapia culture. The development of fish growth model used polynomial growth function. Profit maximization process used the first derivative of profit equation to time of culture equal to zero. This research has also developed the equations to estimate the culture time to reach the target size of the fish harvest. The research proved that this research model could be applied in the red tilapia culture. In the case of this study, red tilapia culture can achieve the maximum profit at 584 days and the profit of Rp. 28,605,731 per culture cycle. If used size target of 250 g, the culture of red tilapia need 82 days of culture time.

Terbutaline accumulates in blood and urine following daily therapeutic inhalation

DEFF Research Database (Denmark)

Krogh, Nanna; Rzeppa, Sebastian; Dyreborg, Anders

2017-01-01

×d) of inhaled terbutaline. After inhalation of terbutaline at each trial, subjects performed 90 min of bike ergometer exercise at 65% of maximal oxygen consumption after which they stayed inactive. Blood and urine samples were collected before and after inhalation of terbutaline. Samples were analyzed by high...

Design for life-cycle profit with simultaneous consideration of initial manufacturing and end-of-life remanufacturing

Science.gov (United States)

Kwak, Minjung; Kim, Harrison

2015-01-01

Remanufacturing is emerging as a promising solution for achieving green, profitable businesses. This article considers a manufacturer that produces new products and also remanufactured versions of the new products that become available at the end of their life cycle. For such a manufacturer, design decisions at the initial design stage determine both the current profit from manufacturing and future profit from remanufacturing. To maximize the total profit, design decisions must carefully consider both ends of product life cycle, i.e. manufacturing and end-of-life stages. This article proposes a decision-support model for the life-cycle design using mixed-integer nonlinear programming. With an aim to maximize the total life-cycle profit, the proposed model searches for an (at least locally) optimal product design (i.e. design specifications and the selling price) for the new and remanufactured products. It optimizes both the initial design and design upgrades at the end-of-life stage and also provides corresponding production strategies, including production quantities and take-back rate. The model is extended to a multi-objective model that maximizes both economic profit and environmental-impact saving. To illustrate, the developed model is demonstrated with an example of a desktop computer.

Heart rate regulation during cycle-ergometer exercise via bio-feedback.

Science.gov (United States)

Argha, Ahmadreza; Su, Steven W; Hung Nguyen; Celler, Branko G

2015-08-01

This paper explains our developed control system which regulates the heart rate (HR) to track a desired trajectory. The controller is indeed a non-conventional non-model-based proportional, integral and derivative (PID) controller. The controller commands are interpreted as biofeedback auditory commands. These commands can be heard and implemented by the exercising subject as a part of the control-loop. However, transmitting a feedback signal while the pedals are not in the appropriate position to efficiently exert force may lead to a cognitive disengagement of the user from the feedback controller. This note explains a novel form of control system regarding as "actuator-based event-driven control system", designed specifically for the purpose of this project. We conclude that the developed event-driven controller makes it possible to precisely regulate HR to a predetermined HR profile.

Maximally multipartite entangled states

Science.gov (United States)

Facchi, Paolo; Florio, Giuseppe; Parisi, Giorgio; Pascazio, Saverio

2008-06-01

We introduce the notion of maximally multipartite entangled states of n qubits as a generalization of the bipartite case. These pure states have a bipartite entanglement that does not depend on the bipartition and is maximal for all possible bipartitions. They are solutions of a minimization problem. Examples for small n are investigated, both analytically and numerically.

Gadolinia experience and design for PWR fuel cycles

International Nuclear Information System (INIS)

Stephenson, L. C.

2000-01-01

The purpose of this paper is to describe Siemens Power Corporation's (SPC) current experience with the burnable absorber gadolinia in PWR fuel assemblies, including optimized features of SPC's PWR gadolinia designs, and comparisons with other burnable absorbers. Siemens is the world leader in PWR gadolinia experience. More than 5,900 Siemens PWR gadolinia-bearing fuel assemblies have been irradiated. The use of gadolinia-bearing fuel provides significant flexibility in fuel cycle designs, allows for low radial leakage fuel management and extended operating cycles, and reduces BOC (beginning-of-cycle) soluble boron concentrations. The optimized use of an integral burnable neutron absorber is a design feature which provides improved economic performance for PWR fuel assemblies. This paper includes a comparison between three different types of integral burnable absorbers: gadolinia, Zirconium diboride and erbia. Fuel cycle design studies performed by Siemens have shown that the enrichment requirements for 18-24 month fuel cycles utilizing gadolinia or zirconium diboride integral fuel burnable absorbers can be approximately the same. Although a typical gadolinia residual penalty for a cycle design of this length is as low as 0.02-0.03 wt% U-235, the design flexibility of gadolinia allows for very aggressive low-leakage core loading plans which reduces the enrichment requirements for gadolinia-bearing fuel. SPC has optimized its use of gadolinia in PWR fuel cycles. Typically, low (2-4) weight percent Gd 2 O 3 is used for beginning to middle of cycle reactivity hold down as well as soluble boron concentration holddown at BOC. Higher concentrations of Gd 2 O 3 , such as 6 and 8 wt%, are used to control power peaking in assemblies later in the cycle. SPC has developed core strategies that maximize the use of lower gadolinia concentrations which significantly reduces the gadolinia residual reactivity penalty. This optimization includes minimizing the number of rods with

Maximally Symmetric Composite Higgs Models.

Science.gov (United States)

Csáki, Csaba; Ma, Teng; Shu, Jing

2017-09-29

Maximal symmetry is a novel tool for composite pseudo Goldstone boson Higgs models: it is a remnant of an enhanced global symmetry of the composite fermion sector involving a twisting with the Higgs field. Maximal symmetry has far-reaching consequences: it ensures that the Higgs potential is finite and fully calculable, and also minimizes the tuning. We present a detailed analysis of the maximally symmetric SO(5)/SO(4) model and comment on its observational consequences.

Muscle fascicle behavior during eccentric cycling and its relation to muscle soreness.

Science.gov (United States)

Peñailillo, Luis; Blazevich, Anthony J; Nosaka, Kazunori

2015-04-01

A single bout of eccentric exercise confers a protective effect against muscle damage and soreness in subsequent eccentric exercise bouts, but the mechanisms underpinning this effect are unclear. This study compared vastus lateralis (VL) muscle-tendon behavior between two eccentric cycling bouts to test the hypothesis that muscle-tendon behavior would be different between bouts and would be associated with the protective effect. Eleven untrained men (27.1 ± 7.0 yr) performed two bouts of eccentric cycling (ECC1 and ECC2) separated by 2 wk for 10 min at 65% of maximal concentric workload (191.9 ± 44.2 W) each. Muscle soreness (by visual analog scale) and maximal voluntary isometric contraction (MVC) torque of the knee extensors were assessed before and 1-2 d after exercise. Using ultrasonography, VL fascicle length and angle changes during cycling were assessed, and tendinous tissue (TT) length changes were estimated. VL EMG amplitude, crank torque, and knee joint angles were measured during cycling. Soreness was greater (P tendon behavior may be an important mechanism underpinning the protective effect.

Maximal quantum Fisher information matrix

International Nuclear Information System (INIS)

Chen, Yu; Yuan, Haidong

2017-01-01

We study the existence of the maximal quantum Fisher information matrix in the multi-parameter quantum estimation, which bounds the ultimate precision limit. We show that when the maximal quantum Fisher information matrix exists, it can be directly obtained from the underlying dynamics. Examples are then provided to demonstrate the usefulness of the maximal quantum Fisher information matrix by deriving various trade-off relations in multi-parameter quantum estimation and obtaining the bounds for the scalings of the precision limit. (paper)

Real-time control strategy to maximize hybrid electric vehicle powertrain efficiency

International Nuclear Information System (INIS)

Shabbir, Wassif; Evangelou, Simos A.

2014-01-01

Highlights: • An off-line local control is proposed for real-time HEV energy management. • Powertrain efficiencies are studied to produce a unified objective function. • Penalty function is designed to ensure charge sustaining operation. • Implementation by storing optimal power share in a two-dimensional control map. • Proposed control improved fuel economy by up to 20% compared to conventional control. - Abstract: The proposed supervisory control system (SCS) uses a control map to maximize the powertrain efficiency of a hybrid electric vehicle (HEV) in real-time. The paper presents the methodology and structure of the control, including a novel, comprehensive and unified expression for the overall powertrain efficiency that considers the engine-generator set and the battery in depth as well as the power electronics. A control map is then produced with instructions for the optimal power share between the engine branch and battery branch of the vehicle such that the powertrain efficiency is maximized. This map is computed off-line and can thereafter be operated in real-time at very low computational cost. A charge sustaining factor is also developed and introduced to ensure the SCS operates the vehicle within desired SOC bounds. This SCS is then tested and benchmarked against two conventional control strategies in a high-fidelity vehicle model, representing a series HEV. Extensive simulation results are presented for repeated cycles of a diverse range of standard driving cycles, showing significant improvements in fuel economy (up to 20%) and less aggressive use of the battery

Understanding Violations of Gricean Maxims in Preschoolers and Adults

Directory of Open Access Journals (Sweden)

Mako eOkanda

2015-07-01

Full Text Available This study used a revised Conversational Violations Test to examine Gricean maxim violations in 4- to 6-year-old Japanese children and adults. Participants’ understanding of the following maxims was assessed: be informative (first maxim of quantity, avoid redundancy (second maxim of quantity, be truthful (maxim of quality, be relevant (maxim of relation, avoid ambiguity (second maxim of manner, and be polite (maxim of politeness. Sensitivity to violations of Gricean maxims increased with age: 4-year-olds’ understanding of maxims was near chance, 5-year-olds understood some maxims (first maxim of quantity and maxims of quality, relation, and manner, and 6-year-olds and adults understood all maxims. Preschoolers acquired the maxim of relation first and had the greatest difficulty understanding the second maxim of quantity. Children and adults differed in their comprehension of the maxim of politeness. The development of the pragmatic understanding of Gricean maxims and implications for the construction of developmental tasks from early childhood to adulthood are discussed.

Comparison of strategies and performance of functional electrical stimulation cycling in spinal cord injury pilots for competition in the first ever CYBATHLON

Directory of Open Access Journals (Sweden)

Christine Azevedo Coste

2017-12-01

Full Text Available Functional Electrical Stimulation (FES can elicit muscular contraction and restore motor function in paralyzed limbs. FES is a rehabilitation technique applied to various sensorimotor deficiencies and in different functional situations, e.g. grasping, walking, standing, transfer, cycling and rowing. FES can be combined with mechanical devices. FES-assisted cycling is mainly used in clinical environments for training sessions on cycle ergometers, but it has also been adapted for mobile devices, usually tricycles. In October 2016, twelve teams participated in the CYBATHLON competition in the FES-cycling discipline for persons with motor-complete spinal cord injury. It was the first event of this kind and a wide variety of strategies, techniques and designs were employed by the different teams in the competition. The approaches of the teams are detailed in this special issue. We hope that the knowledge contained herein, together with recent positive results of FES for denervated degenerating muscles, will provide a solid basis to encourage improvements in FES equipment and open new opportunities for many patients in need of safe and effective FES management. We hope to see further developments and/or the benefit of new training strategies at future FES competitions, e.g. at the Cybathlon 2020 (www.cybathlon.ethz.ch.

Pharmacokinetics of oral and inhaled terbutaline after exercise in trained men

DEFF Research Database (Denmark)

Dyreborg, Anders; Krogh, Nanna; Backer, Vibeke

2016-01-01

that compared 10 mg oral terbutaline with 4 mg inhaled dry powder terbutaline. During each trial, subjects performed 90 min of bike ergometer exercise at 65% of maximal oxygen consumption. Blood (0-4 h) and urine (0-24 h) samples were collected before and after administration of terbutaline. Samples were...

Effects of Uric Acid on Exercise-induced Oxidative Stress

OpenAIRE

平井, 富弘

2001-01-01

We studied effects of uric acid on exercise― induced oxidative stress in humans based on a hypothesis that uric acid acts as an antioxidant to prevent from exercise―induced oxidative stress. Relation between uric acid level in plasma and increase of thiobarbituric acid reactive substance (TBARS)after the cycle ergometer exercise was examined. Thiobarbituricacid reactive substance in plasma increased after the ergometer exercise. High uric acid in plasma did not result in low increase of TBARS...

Cycling above rather than below lactate threshold is more effective for nitric oxide release and post-exercise blood pressure reduction in individuals with type-2 diabetes

Directory of Open Access Journals (Sweden)

Ricardo Yukio Asano

2013-09-01

Full Text Available The purposes of this study were to analyze and compare the effects of exercise performed in different intensities, above and below lactate threshold (LT on post-exercise blood pressure (BP and nitric oxide (NO responses in individuals with type 2 diabetes (T2D. For this, 11 T2D underwent the following sessions: 1 control session; 2 20-min of moderate cycling (80% LT; and 3 20-min of high intensity cycling (120%LT on a cycle ergometer. Plasma NO and BP measurements were carried out at rest and at 15 and 45 min of post-sessions. When compared to rest, only the exercise session performed at 120%LT elicited an increase of NO (from 7.2 to 9.5 µM, p<0.05, as well as a decrease in systolic BP (from 126.6±7.9 to 118.7±3.9 mmHg, p<0.05 during the post-exercise period. In conclusion, the results suggest that NO release and post-exercise BP decrease are intensity-dependent for individuals with T2D.

Comparison of oxygen uptake during and after the execution of resistance exercises and exercises performed on ergometers, matched for intensity

Directory of Open Access Journals (Sweden)

Vilaça-Alves José

2016-12-01

Full Text Available The aim of this study was to compare the values of oxygen uptake (VO2 during and after strength training exercises (STe and ergometer exercises (Ee, matched for intensity and exercise time. Eight men (24 ± 2.33 years performed upper and lower body cycling Ee at the individual’s ventilatory threshold (VE/VCO2. The STe session included half squats and the bench press which were performed with a load at the individual blood lactate concentration of 4 mmol/l. Both sessions lasted 30 minutes, alternating 50 seconds of effort with a 10 second transition time between upper and lower body work. The averaged overall VO2 between sessions was significantly higher for Ee (24.96 ± 3.6 ml·kg·min-1 compared to STe (21.66 ± 1.77 ml·kg·min-1 (p = 0.035, but this difference was only seen for the first 20 minutes of exercise. Absolute VO2 values between sessions did not reveal differences. There were more statistically greater values in Ee compared to STe, regarding VO2 of lower limbs (25.44 ± 3.84 ml·kg·min-1 versus 21.83 ± 2·24 ml·kg·min-1; p = 0.038 and upper limbs (24.49 ± 3.84 ml·kg·min-1 versus 21.54 ± 1.77 ml·kg·min-1; p = 0.047. There were further significant differences regarding the moment effect (p<0.0001 of both STe and Ee sessions. With respect to the moment × session effect, only VO2 5 minutes into recovery showed significant differences (p = 0.017. In conclusion, although significant increases in VO2 were seen following Ee compared to STe, it appears that the load/intensity, and not the material/equipment used for the execution of an exercise, are variables that best influence oxygen uptake.

Cycling efficiency and energy cost of walking in young and older adults.

Science.gov (United States)

Gaesser, Glenn A; Tucker, Wesley J; Sawyer, Brandon J; Bhammar, Dharini M; Angadi, Siddhartha S

2018-02-01

To determine whether age affects cycling efficiency and the energy cost of walking (Cw), 190 healthy adults, ages 18-81 yr, cycled on an ergometer at 50 W and walked on a treadmill at 1.34 m/s. Ventilation and gas exchange at rest and during exercise were used to calculate net Cw and net efficiency of cycling. Compared with the 18-40 yr age group (2.17 ± 0.33 J·kg -1 ·m -1 ), net Cw was not different in the 60-64 yr (2.20 ± 0.40 J·kg -1 ·m -1 ) and 65-69 yr (2.20 ± 0.28 J·kg -1 ·m -1 ) age groups, but was significantly ( P 60 yr, net Cw was significantly correlated with age ( R 2  = 0.123; P = 0.002). Cycling net efficiency was not different between 18-40 yr (23.5 ± 2.9%), 60-64 yr (24.5 ± 3.6%), 65-69 yr (23.3 ± 3.6%) and ≥70 yr (24.7 ± 2.7%) age groups. Repeat tests on a subset of subjects (walking, n = 43; cycling, n = 37) demonstrated high test-retest reliability [intraclass correlation coefficients (ICC), 0.74-0.86] for all energy outcome measures except cycling net energy expenditure (ICC = 0.54) and net efficiency (ICC = 0.50). Coefficients of variation for all variables ranged from 3.1 to 7.7%. Considerable individual variation in Cw and efficiency was evident, with a ~2-fold difference between the least and most economical/efficient subjects. We conclude that, between 18 and 81 yr, net Cw was only higher for ages ≥70 yr, and that cycling net efficiency was not different across age groups. NEW & NOTEWORTHY This study illustrates that the higher energy cost of walking in older adults is only evident for ages ≥70 yr. For older adults ages 60-69 yr, the energy cost of walking is similar to that of young adults. Cycling efficiency, by contrast, is not different across age groups. Considerable individual variation (∼2-fold) in cycling efficiency and energy cost of walking is observed in young and older adults.

High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients

Science.gov (United States)

Madsen, Søren Møller; Thorup, Anne Cathrine; Overgaard, Kristian; Jeppesen, Per Bendix

2015-01-01

Physical activity improves the regulation of glucose homeostasis in both type 2 diabetes (T2D) patients and healthy individuals, but the effect on pancreatic β cell function is unknown. We investigated glycaemic control, pancreatic function and total fat mass before and after 8 weeks of low volume high intensity interval training (HIIT) on cycle ergometer in T2D patients and matched healthy control individuals. Study design/method: Elderly (56 yrs±2), non-active T2D patients (n = 10) and matched (52 yrs±2) healthy controls (CON) (n = 13) exercised 3 times (10×60 sec. HIIT) a week over an 8 week period on a cycle ergometer. Participants underwent a 2-hour oral glucose tolerance test (OGTT). On a separate day, resting blood pressure measurement was conducted followed by an incremental maximal oxygen uptake (V˙O2max) cycle ergometer test. Finally, a whole body dual X-ray absorptiometry (DXA) was performed. After 8 weeks of training, the same measurements were performed. Results: in the T2D-group, glycaemic control as determined by average fasting venous glucose concentration (p = 0.01), end point 2-hour OGTT (p = 0.04) and glycosylated haemoglobin (p = 0.04) were significantly reduced. Pancreatic homeostasis as determined by homeostatic model assessment of insulin resistance (HOMA-IR) and HOMA β cell function (HOMA-%β) were both significantly ameliorated (p = 0.03 and p = 0.03, respectively). Whole body insulin sensitivity as determined by the disposition index (DI) was significantly increased (p = 0.03). During OGTT, the glucose continuum was significantly reduced at -15 (p = 0.03), 30 (p = 0.03) and 120 min (p = 0.03) and at -10 (p = 0.003) and 0 min (p = 0.003) with an additional improvement (p = 0.03) of its 1st phase (30 min) area under curve (AUC). Significant abdominal fat mass losses were seen in both groups (T2D: p = 0.004 and CON: p = 0.02) corresponding to a percentage change of -17.84%±5.02 and -9.66%±3.07, respectively. Conclusion: these results

High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients.

Directory of Open Access Journals (Sweden)

Søren Møller Madsen

Full Text Available Physical activity improves the regulation of glucose homeostasis in both type 2 diabetes (T2D patients and healthy individuals, but the effect on pancreatic β cell function is unknown. We investigated glycaemic control, pancreatic function and total fat mass before and after 8 weeks of low volume high intensity interval training (HIIT on cycle ergometer in T2D patients and matched healthy control individuals. Study design/method: Elderly (56 yrs±2, non-active T2D patients (n = 10 and matched (52 yrs±2 healthy controls (CON (n = 13 exercised 3 times (10×60 sec. HIIT a week over an 8 week period on a cycle ergometer. Participants underwent a 2-hour oral glucose tolerance test (OGTT. On a separate day, resting blood pressure measurement was conducted followed by an incremental maximal oxygen uptake (VO2max cycle ergometer test. Finally, a whole body dual X-ray absorptiometry (DXA was performed. After 8 weeks of training, the same measurements were performed. Results: in the T2D-group, glycaemic control as determined by average fasting venous glucose concentration (p = 0.01, end point 2-hour OGTT (p = 0.04 and glycosylated haemoglobin (p = 0.04 were significantly reduced. Pancreatic homeostasis as determined by homeostatic model assessment of insulin resistance (HOMA-IR and HOMA β cell function (HOMA-%β were both significantly ameliorated (p = 0.03 and p = 0.03, respectively. Whole body insulin sensitivity as determined by the disposition index (DI was significantly increased (p = 0.03. During OGTT, the glucose continuum was significantly reduced at -15 (p = 0.03, 30 (p = 0.03 and 120 min (p = 0.03 and at -10 (p = 0.003 and 0 min (p = 0.003 with an additional improvement (p = 0.03 of its 1st phase (30 min area under curve (AUC. Significant abdominal fat mass losses were seen in both groups (T2D: p = 0.004 and CON: p = 0.02 corresponding to a percentage change of -17.84%±5.02 and -9.66%±3.07, respectively. Conclusion: these results

Circulating adiponectin concentration and body composition are altered in response to high-intensity interval training.

Science.gov (United States)

Shing, Cecilia M; Webb, Jessica J; Driller, Matthew W; Williams, Andrew D; Fell, James W

2013-08-01

Adiponectin influences metabolic adaptations that would prove beneficial to endurance athletes, and yet to date there is little known about the response of adiponectin concentrations to exercise, and, in particular, the response of this hormone to training in an athlete population. This study aimed to determine the response of plasma adiponectin concentrations to acute exercise after 2 different training programs and to determine the influence of the training on body composition. Seven state-level representative rowers (age: 19 ± 1.2 years [mean ± SD], height: 1.77 ± 0.10 m, body mass: 74.0 ± 10.7 kg, VO2peak 62.1 ± 7.0 ml·kg·min) participated in the double-blind, randomized crossover investigation. Rowers performed an incremental graded exercise test before and after completing 4 weeks of high-intensity interval ergometer training and 4 weeks of traditional ergometer rowing training. Rowers' body composition was assessed at baseline and after each training program. Significant increases in plasma adiponectin concentration occurred in response to maximal exercise after completion of the high-intensity interval training (p = 0.016) but not after traditional ergometer rowing training (p = 0.69). The high-intensity interval training also resulted in significant increases in mean 4-minute power output (p = 0.002) and VO2peak (p = 0.05), and a decrease in body fat percentage (p = 0.022). Mean 4-minute power output, VO2peak, and body fat percentage were not significantly different after 4 weeks of traditional ergometer rowing training (p > 0.05). Four weeks of high-intensity interval training is associated with an increase in adiponectin concentration in response to maximal exercise and a reduction in body fat percentage. The potential for changes in adiponectin concentration to reflect positive training adaptations and athlete performance level should be further explored.

Review of low-temperature vapour power cycle engines with quasi-isothermal expansion

OpenAIRE

Igobo, Opubo N.; Davies, Philip A.

2014-01-01

External combustion heat cycle engines convert thermal energy into useful work. Thermal energy resources include solar, geothermal, bioenergy, and waste heat. To harness these and maximize work output, there has been a renaissance of interest in the investigation of vapour power cycles for quasi-isothermal (near constant temperature) instead of adiabatic expansion. Quasi-isothermal expansion has the advantage of bringing the cycle efficiency closer to the ideal Carnot efficiency, but it requi...

Models for optimum thermo-ecological criteria of actual thermal cycles

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Açikkalp Emin

2013-01-01

Full Text Available In this study, the ecological optimization point of irreversible thermal cycles (refrigerator, heat pump and power cycles was investigated. The importance of ecological optimization is to propose a way to use fuels and energy source more efficiently because of an increasing energy need and environmental pollution. It provides this by maximizing obtained (or minimizing supplied work and minimizing entropy generation for irreversible (actual thermal cycles. In this research, ecological optimization was defined for all basic irreversible thermal cycles, by using the first and second laws of thermodynamics. Finally, the ecological optimization was defined in thermodynamic cycles and results were given to show the effects of the cycles’ ecological optimization point, efficiency, COP and power output (or input, and exergy destruction.

On maximal massive 3D supergravity

OpenAIRE

Bergshoeff , Eric A; Hohm , Olaf; Rosseel , Jan; Townsend , Paul K

2010-01-01

ABSTRACT We construct, at the linearized level, the three-dimensional (3D) N = 4 supersymmetric " general massive supergravity " and the maximally supersymmetric N = 8 " new massive supergravity ". We also construct the maximally supersymmetric linearized N = 7 topologically massive supergravity, although we expect N = 6 to be maximal at the non-linear level. (Bergshoeff, Eric A) (Hohm, Olaf) (Rosseel, Jan) P.K.Townsend@da...

Optimization of Organic Rankine Cycles for Off-Shore Applications

DEFF Research Database (Denmark)

Pierobon, Leonardo; Larsen, Ulrik; Nguyen, Tuong-Van

2013-01-01

and the thermal efficiency of the cycle can be maximized. This paper is aimed at finding the most optimal ORC tailored for off-shore applications using an optimization procedure based on the genetic algorithm. Numerous working fluids are screened through, considering mainly thermal efficiency, but also other...

Parametric conversion and maximally entangled photon pair via collective excitations in a cycle atomic ensemble

International Nuclear Information System (INIS)

Li, J.; Yu, R.; Yang, X.

2008-01-01

We study the propagation of two quantized optical fields via considering the collective effects of photonic emissions and excitations of a three-level cyclic-type system (such as atomic ensemble with symmetry broken, or the chiral molecular gases, or manual 'atomic' array with symmetry broken), where the quantum transitions is driven by two quantized fields and a classical one. The results show that the parametric conversion and maximally entangled photon pair generation can be achieved by means of the collective excitation of the two upper energy levels induced by the classic optical field. This investigation may be used for the generated coherent short-wavelength quantum radiation and quantum information processing

Impact of advanced fuel cycle options on waste management policies

International Nuclear Information System (INIS)

Gordelier, Stan; Cavedon, Jean-Marc

2006-01-01

OECD/NEA has performed a study on the impact of advanced fuel cycle options on waste management policies with 33 experts from 12 member countries, 1 non-member country and 2 international organizations. The study extends a series of previous ones on partitioning and transmutation (P and T) issues, focusing on the performance assessments for repositories of high-level waste (HLW) arising from advanced fuel cycles. This study covers a broader spectrum than previous studies, from present industrial practice to fully closed cycles via partially closed cycles (in terms of transuranic elements); 9 fuel cycle schemes and 4 variants. Elements of fuel cycles are considered primarily as sources of waste, the internal mass flows of each scheme being kept for the sake of mass conservation. The compositions, activities and heat loads of all waste flows are also tracked. Their impact is finally assessed on the waste repository concepts. The study result confirms the findings from the previous NEA studies on P and T on maximal reduction of the waste source term and maximal use of uranium resources. In advanced fuel cycle schemes the activity of the waste is reduced by burning first plutonium and then minor actinides and also the uranium consumption is reduced, as the fraction of fast reactors in the park is increased to 100%. The result of the repository performance assessments, analysing the effect of different HLW isotopic composition on repository performance and on repository capacity, shows that the maximum dose released to biosphere at any time in normal conditions remains, for all schemes and for all the repository concepts examined, well below accepted radiation protection thresholds. The major impact is on the detailed concept of the repositories, through heat load and waste volume. Advanced fuel cycles could allow a repository to cover waste produced from 5 to 20 times more electricity generation than PWR once-through cycle. Given the flexibility of the advanced fuel

Inclusive fitness maximization: An axiomatic approach.

Science.gov (United States)

Okasha, Samir; Weymark, John A; Bossert, Walter

2014-06-07

Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of quasi-inclusive fitness maximization can be derived from axioms on an individual׳s 'as if preferences' (binary choices) for the case in which phenotypic effects are additive. Our results help integrate evolutionary theory and rational choice theory, help draw out the behavioural implications of inclusive fitness maximization, and point to a possible way in which evolution could lead organisms to implement it. Copyright © 2014 Elsevier Ltd. All rights reserved.

Metabolic Engineering of TCA Cycle for Production of Chemicals.

Science.gov (United States)

Vuoristo, Kiira S; Mars, Astrid E; Sanders, Johan P M; Eggink, Gerrit; Weusthuis, Ruud A

2016-03-01

The tricarboxylic acid (TCA) cycle has been used for decades in the microbial production of chemicals such as citrate, L-glutamate, and succinate. Maximizing yield is key for cost-competitive production. However, for most TCA cycle products, the maximum pathway yield is lower than the theoretical maximum yield (Y(E)). For succinate, this was solved by creating two pathways to the product, using both branches of the TCA cycle, connected by the glyoxylate shunt (GS). A similar solution cannot be applied directly for production of compounds from the oxidative branch of the TCA cycle because irreversible reactions are involved. Here, we describe how this can be overcome and what the impact is on the yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Lyapunov based approach to energy maximization in renewable energy technologies

Science.gov (United States)

Iyasere, Erhun

This dissertation describes the design and implementation of Lyapunov-based control strategies for the maximization of the power captured by renewable energy harnessing technologies such as (i) a variable speed, variable pitch wind turbine, (ii) a variable speed wind turbine coupled to a doubly fed induction generator, and (iii) a solar power generating system charging a constant voltage battery. First, a torque control strategy is presented to maximize wind energy captured in variable speed, variable pitch wind turbines at low to medium wind speeds. The proposed strategy applies control torque to the wind turbine pitch and rotor subsystems to simultaneously control the blade pitch and tip speed ratio, via the rotor angular speed, to an optimum point at which the capture efficiency is maximum. The control method allows for aerodynamic rotor power maximization without exact knowledge of the wind turbine model. A series of numerical results show that the wind turbine can be controlled to achieve maximum energy capture. Next, a control strategy is proposed to maximize the wind energy captured in a variable speed wind turbine, with an internal induction generator, at low to medium wind speeds. The proposed strategy controls the tip speed ratio, via the rotor angular speed, to an optimum point at which the efficiency constant (or power coefficient) is maximal for a particular blade pitch angle and wind speed by using the generator rotor voltage as a control input. This control method allows for aerodynamic rotor power maximization without exact wind turbine model knowledge. Representative numerical results demonstrate that the wind turbine can be controlled to achieve near maximum energy capture. Finally, a power system consisting of a photovoltaic (PV) array panel, dc-to-dc switching converter, charging a battery is considered wherein the environmental conditions are time-varying. A backstepping PWM controller is developed to maximize the power of the solar generating

Maximal Entanglement in High Energy Physics

Directory of Open Access Journals (Sweden)

Alba Cervera-Lierta, José I. Latorre, Juan Rojo, Luca Rottoli

2017-11-01

Full Text Available We analyze how maximal entanglement is generated at the fundamental level in QED by studying correlations between helicity states in tree-level scattering processes at high energy. We demonstrate that two mechanisms for the generation of maximal entanglement are at work: i $s$-channel processes where the virtual photon carries equal overlaps of the helicities of the final state particles, and ii the indistinguishable superposition between $t$- and $u$-channels. We then study whether requiring maximal entanglement constrains the coupling structure of QED and the weak interactions. In the case of photon-electron interactions unconstrained by gauge symmetry, we show how this requirement allows reproducing QED. For $Z$-mediated weak scattering, the maximal entanglement principle leads to non-trivial predictions for the value of the weak mixing angle $\\theta_W$. Our results are a first step towards understanding the connections between maximal entanglement and the fundamental symmetries of high-energy physics.

Design and optimization of air bottoming cycles for waste heat recovery in off-shore platforms

DEFF Research Database (Denmark)

Pierobon, Leonardo; Haglind, Fredrik

2014-01-01

This paper aims at comparing two methodologies to design an air bottoming cycle recovering the waste heat from the power generation system on the Draugen off-shore oil and gas platform. Firstly, the design is determined using the theory of the power maximization. Subsequently, the multi-objective......This paper aims at comparing two methodologies to design an air bottoming cycle recovering the waste heat from the power generation system on the Draugen off-shore oil and gas platform. Firstly, the design is determined using the theory of the power maximization. Subsequently, the multi....... Findings indicate that using the power production, the volume of the recuperator and the net present value as objective functions the optimal pressure ratio (2.52) and the exhaust gas temperature (178.8 °C) differ from the values (2.80 and 145.5 °C) calculated using the theory of the power maximization...

Maximal Inequalities for Dependent Random Variables

DEFF Research Database (Denmark)

Hoffmann-Jorgensen, Jorgen

2016-01-01

Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X-k. Then a......Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X......-k. Then a maximal inequality gives conditions ensuring that the maximal partial sum M-n = max(1) (...

An ethical justification of profit maximization

DEFF Research Database (Denmark)

Koch, Carsten Allan

2010-01-01

In much of the literature on business ethics and corporate social responsibility, it is more or less taken for granted that attempts to maximize profits are inherently unethical. The purpose of this paper is to investigate whether an ethical argument can be given in support of profit maximizing...... behaviour. It is argued that some form of consequential ethics must be applied, and that both profit seeking and profit maximization can be defended from a rule-consequential point of view. It is noted, however, that the result does not apply unconditionally, but requires that certain form of profit (and...... utility) maximizing actions are ruled out, e.g., by behavioural norms or formal institutions....

Effects of music on work-rate distribution during a cycling time trial.

Science.gov (United States)

Atkinson, G; Wilson, D; Eubank, M

2004-11-01

Previous research work on the ergogenic effects of music has mainly involved constant power tests to exhaustion as dependent variables. Time trials are more externally valid than constant power tests, may be more reliable and allow the distribution of self-selected work-rate to be explored. We examined whether music improved starting, finishing and/or overall power during a 10-km cycling time trial, and whether heart rate and subjective responses to this time trial were altered by music. Sixteen participants performed two 10-km time trials on a Cybex cycle ergometer with, and without, the presence of a form of dance music known as "trance" (tempo = 142 beats x min (-1), volume at ear = 87 dB). Participants also completed the Brunel music rating inventory (BMRI) after each time trial in the music condition. The mean +/- SD time to complete the time trial was 1030 +/- 79 s in the music condition compared to 1052 +/- 77 s without music (95 % CI of difference = 10 to 34 s, p = 0.001). Nevertheless, ratings of perceived exertion were consistently (0.8 units) higher throughout the time trial with music (p music-induced increases in cycling speed and heart rate were observed in the first 3 km of the time trial. After completion of the BMRI, participants rated the "tempo" and "rhythm" of the music as more motivating than the "harmony" and "melody" aspects. These results suggest that music improves cycling speed mostly in the first few minutes of a 10-km time trial. In contrast to the findings of previous research, which suggested that music lowers perceived exertion at a constant work-rate, the participants in our time trials selected higher work-rates with music, whilst at the same time perceived these work-rates as being harder than without music.

Recruitment of single muscle fibers during submaximal cycling exercise

NARCIS (Netherlands)

Altenburg, T.M.; Degens, H.; van Mechelen, W.; Sargeant, A.J.; de Haan, A.

2007-01-01

In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which

Inclusive Fitness Maximization:An Axiomatic Approach

OpenAIRE

Okasha, Samir; Weymark, John; Bossert, Walter

2014-01-01

Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of qu...

Does mental exertion alter maximal muscle activation?

Directory of Open Access Journals (Sweden)

Vianney eRozand

2014-09-01

Full Text Available Mental exertion is known to impair endurance performance, but its effects on neuromuscular function remain unclear. The purpose of this study was to test the hypothesis that mental exertion reduces torque and muscle activation during intermittent maximal voluntary contractions of the knee extensors. Ten subjects performed in a randomized order three separate mental exertion conditions lasting 27 minutes each: i high mental exertion (incongruent Stroop task, ii moderate mental exertion (congruent Stroop task, iii low mental exertion (watching a movie. In each condition, mental exertion was combined with ten intermittent maximal voluntary contractions of the knee extensor muscles (one maximal voluntary contraction every 3 minutes. Neuromuscular function was assessed using electrical nerve stimulation. Maximal voluntary torque, maximal muscle activation and other neuromuscular parameters were similar across mental exertion conditions and did not change over time. These findings suggest that mental exertion does not affect neuromuscular function during intermittent maximal voluntary contractions of the knee extensors.

Cycling peak power in obese and lean 6- to 8-year-old girls and boys.

Science.gov (United States)

Aucouturier, Julien; Lazaar, Nordine; Doré, Eric; Meyer, Martine; Ratel, Sebastien; Duché, Pascale

2007-06-01

The purpose of this study was to investigate the possible effect of the difference in percentage body fat (%BF) and fat-free mass (FFM) on cycling peak power (CPP) in 6- to 8-year-old obese and lean untrained girls and boys. Obese (35 girls, 35 boys) and lean (35 girls, 35 boys) children were measured for obesity, %BF, calculated from skinfold measurements. FFM was calculated as body mass (BM) minus body fat. A force-velocity test on a cycle ergometer was used to measure CPP. CPP was related to anthropometric variables using standard and allometric models. CPP in absolute terms was higher in obese children than in lean children irrespective of gender. BM-related CPP was significantly lower in obese children than in lean ones, whereas no effect of obesity appeared on FFM-related CPP. Velocity at CPP (Vopt) was significantly lower and force at CPP (Fopt) was significantly higher in girls than in boys. Muscle power production was unaffected by obesity in children. Low BM-related CPP could explain the difficulty of taking up physical activities that are body-mass related in obese children. Gender difference for Vopt and Fopt shows that girls and boys may have different maturation patterns affecting CPP.

Familial aggregation of VO(2max) response to exercise training: results from the HERITAGE Family Study.

Science.gov (United States)

Bouchard, C; An, P; Rice, T; Skinner, J S; Wilmore, J H; Gagnon, J; Pérusse, L; Leon, A S; Rao, D C

1999-09-01

The aim of this study was to test the hypothesis that individual differences in the response of maximal O(2) uptake (VO(2max)) to a standardized training program are characterized by familial aggregation. A total of 481 sedentary adult Caucasians from 98 two-generation families was exercise trained for 20 wk and was tested for VO(2max) on a cycle ergometer twice before and twice after the training program. The mean increase in VO(2max) reached approximately 400 ml/min, but there was considerable heterogeneity in responsiveness, with some individuals experiencing little or no gain, whereas others gained >1.0 l/min. An ANOVA revealed that there was 2.5 times more variance between families than within families in the VO(2max) response variance. With the use of a model-fitting procedure, the most parsimonious models yielded a maximal heritability estimate of 47% for the VO(2max) response, which was adjusted for age and sex with a maternal transmission of 28% in one of the models. We conclude that the trainability of VO(2max) is highly familial and includes a significant genetic component.

Seasonal Redistribution of Immune Function in a Migrant Shorebird : Annual-Cycle Effects Override Adjustments to Thermal Regime

NARCIS (Netherlands)

Buehler, Deborah M.; Piersma, Theunis; Matson, Kevin D.; Tieleman, B. Irene; Demas, Greg (associate); Geber, Monica A.

2008-01-01

Throughout the annual cycle, demands on competing physiological systems change, and animals must allocate resources to maximize fitness. Immune function is one such system and is important for survival. Yet detailed empirical data tracking immune function over the entire annual cycle are lacking for

On maximal surfaces in asymptotically flat space-times

International Nuclear Information System (INIS)

Bartnik, R.; Chrusciel, P.T.; O Murchadha, N.

1990-01-01

Existence of maximal and 'almost maximal' hypersurfaces in asymptotically flat space-times is established under boundary conditions weaker than those considered previously. We show in particular that every vacuum evolution of asymptotically flat data for Einstein equations can be foliated by slices maximal outside a spatially compact set and that every (strictly) stationary asymptotically flat space-time can be foliated by maximal hypersurfaces. Amongst other uniqueness results, we show that maximal hypersurface can be used to 'partially fix' an asymptotic Poincare group. (orig.)

Insulin resistance and maximal oxygen uptake

DEFF Research Database (Denmark)

Seibaek, Marie; Vestergaard, Henrik; Burchardt, Hans

2003-01-01

BACKGROUND: Type 2 diabetes, coronary atherosclerosis, and physical fitness all correlate with insulin resistance, but the relative importance of each component is unknown. HYPOTHESIS: This study was undertaken to determine the relationship between insulin resistance, maximal oxygen uptake......, and the presence of either diabetes or ischemic heart disease. METHODS: The study population comprised 33 patients with and without diabetes and ischemic heart disease. Insulin resistance was measured by a hyperinsulinemic euglycemic clamp; maximal oxygen uptake was measured during a bicycle exercise test. RESULTS......: There was a strong correlation between maximal oxygen uptake and insulin-stimulated glucose uptake (r = 0.7, p = 0.001), and maximal oxygen uptake was the only factor of importance for determining insulin sensitivity in a model, which also included the presence of diabetes and ischemic heart disease. CONCLUSION...

Dynamic modelling of the expansion cylinder of an open Joule cycle Ericsson engine: A bond graph approach

International Nuclear Information System (INIS)

Creyx, M.; Delacourt, E.; Morin, C.; Desmet, B.

2016-01-01

A dynamic model using the bond graph formalism of the expansion cylinder of an open Joule cycle Ericsson engine intended for a biomass-fuelled micro-CHP system is presented. Dynamic phenomena, such as the thermodynamic evolution of air, the instantaneous air mass flow rates linked to pressure drops crossing the valves, the heat transferred through the expansion cylinder wall and the mechanical friction losses, are included in the model. The influence on the Ericsson engine performances of the main operating conditions (intake air pressure and temperature, timing of intake and exhaust valve closing, rotational speed, mechanical friction losses and heat transfer at expansion cylinder wall) is studied. The operating conditions maximizing the performances of the Ericsson engine used in the a biomass-fuelled micro-CHP unit are an intake air pressure between 6 and 8 bar, a maximized intake air temperature, an adjustment of the intake and exhaust valve closing corresponding to an expansion cycle close to the theoretical Joule cycle, a rotational speed close to 800 rpm. The heat transfer at the expansion cylinder wall reduces the engine performances. - Highlights: • A bond graph dynamic model of the Ericsson engine expansion cylinder is presented. • Dynamic aspects are modelled: pressure drops, friction losses, wall heat transfer. • Influent factors and phenomena on the engine performances are investigated. • Expansion cycles close to the theoretical Joule cycle maximize the performances. • The heat transfer at the expansion chamber wall reduces the performances.

POLITENESS MAXIM OF MAIN CHARACTER IN SECRET FORGIVEN

Directory of Open Access Journals (Sweden)

Sang Ayu Isnu Maharani

2017-06-01

Full Text Available Maxim of Politeness is an interesting subject to be discussed, since politeness has been criticized from our childhood. We are obliques to be polite to anyone either in speaking or in acting. Somehow we are manage to show politeness in our spoken expression though our intention might be not so polite. For example we must appriciate others opinion although we feel objection toward the opinion. In this article the analysis of politeness is based on maxim proposes by Leech. He proposed six types of politeness maxim. The discussion shows that the main character (Kristen and Kami use all types of maxim in their conversation. The most commonly used are approbation maxim and agreement maxim

A Life-Cycle Overlapping-Generations Model of the Small Open Economy

NARCIS (Netherlands)

Heijdra, Ben J.; Romp, Ward E.

2005-01-01

In this paper we construct an overlapping generations model for the small open economy incorporating a realistic description of the mortality process. With agedependent mortality, the typical life-cycle pattern of consumption and saving results from the maximizing behaviour of individual households.

NATURAL GAS LIQUEFACTION UNITS ON THE BASE OF EXPANDER NITROGEN CYCLES

OpenAIRE

Кузьменко, И. Ф.; Передельский, В. А.; Довбиш, А. Л.

2014-01-01

It is necessary to create large-capacity LNG-units for natural gas peaks consumption shaving and also to expand liquefied natural gas (LNG) marketing. It is proposed to create such natural gas liquefaction units with the use of outer nitrogen cryogenic thermodynamic cycles. It is necessary to use turboexpander-compressor sets (TECS) in them for maximizing cycles efficiency. Different technological schemes of LNG-units including nitrogen cryogenic units with TECS from one to four have been exa...

Aerobic fitness in patients with fibrositis. A controlled study of respiratory gas exchange and 133-xenon clearance from exercising muscle

International Nuclear Information System (INIS)

Bennett, R.M.; Clark, S.R.; Goldberg, L.; Nelson, D.; Bonafede, R.P.; Porter, J.; Specht, D.

1989-01-01

Aerobic fitness was evaluated in 25 women with fibrositis, by having them exercise to volitional exhaustion on an electronically braked cycle ergometer. Compared with published standards, greater than 80% of the fibrositis patients were not physically fit, as assessed by maximal oxygen uptake. Compared with matched sedentary controls, fibrositis patients accurately perceived their level of exertion in relation to oxygen consumption and attained a similar level of lactic acidosis, as assessed by their respiratory quotient and ventilatory threshold. Exercising muscle blood flow was estimated by 133-xenon clearance in a subgroup of 16 fibrositis patients and compared with that in 16 matched sedentary controls; the fibrositis patients exhibited reduced 133-xenon clearance. These results indicate a need to include aerobic fitness as a matched variable in future controlled studies of fibrositis and suggest that the detraining phenomenon may be of relevance to the etiopathogenesis of the disease

Natural maximal νμ-ντ mixing

International Nuclear Information System (INIS)

Wetterich, C.

1999-01-01

The naturalness of maximal mixing between myon- and tau-neutrinos is investigated. A spontaneously broken nonabelian generation symmetry can explain a small parameter which governs the deviation from maximal mixing. In many cases all three neutrino masses are almost degenerate. Maximal ν μ -ν τ -mixing suggests that the leading contribution to the light neutrino masses arises from the expectation value of a heavy weak triplet rather than from the seesaw mechanism. In this scenario the deviation from maximal mixing is predicted to be less than about 1%. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Gaussian maximally multipartite-entangled states

Science.gov (United States)

Facchi, Paolo; Florio, Giuseppe; Lupo, Cosmo; Mancini, Stefano; Pascazio, Saverio

2009-12-01

We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7 .

Gaussian maximally multipartite-entangled states

International Nuclear Information System (INIS)

Facchi, Paolo; Florio, Giuseppe; Pascazio, Saverio; Lupo, Cosmo; Mancini, Stefano

2009-01-01

We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7.

Utility maximization and mode of payment

NARCIS (Netherlands)

Koning, R.H.; Ridder, G.; Heijmans, R.D.H.; Pollock, D.S.G.; Satorra, A.

2000-01-01

The implications of stochastic utility maximization in a model of choice of payment are examined. Three types of compatibility with utility maximization are distinguished: global compatibility, local compatibility on an interval, and local compatibility on a finite set of points. Keywords:

Relation between Peak Power Output in Sprint Cycling and Maximum Voluntary Isometric Torque Production.

Science.gov (United States)

Kordi, Mehdi; Goodall, Stuart; Barratt, Paul; Rowley, Nicola; Leeder, Jonathan; Howatson, Glyn

2017-08-01

From a cycling paradigm, little has been done to understand the relationships between maximal isometric strength of different single joint lower body muscle groups and their relation with, and ability to predict PPO and how they compare to an isometric cycling specific task. The aim of this study was to establish relationships between maximal voluntary torque production from isometric single-joint and cycling specific tasks and assess their ability to predict PPO. Twenty male trained cyclists participated in this study. Peak torque was measured by performing maximum voluntary contractions (MVC) of knee extensors, knee flexors, dorsi flexors and hip extensors whilst instrumented cranks measured isometric peak torque from MVC when participants were in their cycling specific position (ISOCYC). A stepwise regression showed that peak torque of the knee extensors was the only significant predictor of PPO when using SJD and accounted for 47% of the variance. However, when compared to ISOCYC, the only significant predictor of PPO was ISOCYC, which accounted for 77% of the variance. This suggests that peak torque of the knee extensors was the best single-joint predictor of PPO in sprint cycling. Furthermore, a stronger prediction can be made from a task specific isometric task. Copyright © 2017 Elsevier Ltd. All rights reserved.

Underwater Cycle Ergometry: Power Requirements With and Without Diver Thermal Dress

Science.gov (United States)

2009-01-01

waterproofed Collins Pedal Mate ergometers that are no longer available. A pedal shaft drives the shaft of a hysteresis brake (HB210, Magtrol; Buffalo, NY...NEDU, regular bicycle pedals with toe straps/ over canvas shoes were used in Buffalo (personal 13 communication). The foot cups used at NEDU are

Strength Training Prior to Endurance Exercise: Impact on the Neuromuscular System, Endurance Performance and Cardiorespiratory Responses

Directory of Open Access Journals (Sweden)

Conceição Matheus

2014-12-01

Full Text Available This study aimed to investigate the acute effects of two strength-training protocols on the neuromuscular and cardiorespiratory responses during endurance exercise. Thirteen young males (23.2 ± 1.6 years old participated in this study. The hypertrophic strength-training protocol was composed of 6 sets of 8 squats at 75% of maximal dynamic strength. The plyometric strength-training protocol was composed of 6 sets of 8 jumps performed with the body weight as the workload. Endurance exercise was performed on a cycle ergometer at a power corresponding to the second ventilatory threshold until exhaustion. Before and after each protocol, a maximal voluntary contraction was performed, and the rate of force development and electromyographic parameters were assessed. After the hypertrophic strengthtraining and plyometric strength-training protocol, significant decreases were observed in the maximal voluntary contraction and rate of force development, whereas no changes were observed in the electromyographic parameters. Oxygen uptake and a heart rate during endurance exercise were not significantly different among the protocols. However, the time-to-exhaustion was significantly higher during endurance exercise alone than when performed after hypertrophic strength-training or plyometric strength-training (p <0.05. These results suggest that endurance performance may be impaired when preceded by strength-training, with no oxygen uptake or heart rate changes during the exercise.

Isometric strength training lowers the O2 cost of cycling during moderate-intensity exercise.

Science.gov (United States)

Zoladz, Jerzy A; Szkutnik, Zbigniew; Majerczak, Joanna; Grandys, Marcin; Duda, Krzysztof; Grassi, Bruno

2012-12-01

The effect of maximal voluntary isometric strength training of knee extensor muscles on pulmonary V'O(2) on-kinetics, the O(2) cost of cycling and peak oxygen uptake (V'O(2peak)) in humans was studied. Seven healthy males (mean ± SD, age 22.3 ± 2.0 years, body weight 75.0 ± 9.2 kg, V'O(2peak) 49.5 ± 3.8 ml kg(-1) min(-1)) performed maximal isometric strength training lasting 7 weeks (4 sessions per week). Force during maximal voluntary contraction (MVC) increased by 15 % (P Strength training resulted in a significant decrease (by ~7 %; P Isometric strength training rapidly (i.e., after 1 week) decreases the O(2) cost of cycling during moderate-intensity exercise, whereas it does not affect the amplitude of the slow component of the V'O(2) on-kinetics during heavy-intensity exercise. Isometric strength training can have beneficial effects on performance during endurance events.

An integrated optimization for organic Rankine cycle based on entransy theory and thermodynamics

International Nuclear Information System (INIS)

Li, Tailu; Fu, Wencheng; Zhu, Jialing

2014-01-01

The organic Rankine cycle has been one of the essential heat-work conversion technologies nowadays. Lots of effectual optimization methods are focused on the promotion of the system efficiency, which are mainly relied on engineering experience and numerical simulations rather than theoretical analysis. A theoretical integrated optimization method was established based on the entransy theory and thermodynamics, with the ratio of the net power output to the ratio of the total thermal conductance to the thermal conductance in the condenser as the objective function. The system parameters besides the optimal pinch point temperature difference were obtained. The results show that the mass flow rate of the working fluid is inversely proportional to the evaporating temperature. An optimal evaporating temperature maximizes the net power output, and the maximal net power output corresponds to the maximal entransy loss and the change points of the heat source outlet temperature and the change rates for the entropy generation and the entransy dissipation. Moreover, the net power output and the total thermal conductance are inversely proportional to the pinch point temperature difference, contradicting with each other. Under the specified condition, the optimal operating parameters are ascertained, with the optimal pinch point temperature difference of 5 K. - Highlights: • We establish an integrated optimization model for organic Rankine cycle. • The model combines the entransy theory with thermodynamics. • The maximal net power output corresponds to the maximal entransy loss. • The pinch point temperature difference is optimized to be 5 K

Adopting Technology: Using Student Qualitative Data and Gartner's Hype Cycle

Science.gov (United States)

Grundmeyer, Trent

2014-01-01

Technology is changing education. School leaders are charged with purchasing and leveraging technology to maximize an ever-changing landscape of teaching and learning. They have many factors to consider as they make decisions about what specific technologies to purchase for their schools. Gartner's Hype Cycle is an annually published report that…

Activity versus outcome maximization in time management.

Science.gov (United States)

Malkoc, Selin A; Tonietto, Gabriela N

2018-04-30

Feeling time-pressed has become ubiquitous. Time management strategies have emerged to help individuals fit in more of their desired and necessary activities. We provide a review of these strategies. In doing so, we distinguish between two, often competing, motives people have in managing their time: activity maximization and outcome maximization. The emerging literature points to an important dilemma: a given strategy that maximizes the number of activities might be detrimental to outcome maximization. We discuss such factors that might hinder performance in work tasks and enjoyment in leisure tasks. Finally, we provide theoretically grounded recommendations that can help balance these two important goals in time management. Published by Elsevier Ltd.

Relationship between body composition, leg strength, anaerobic power, and on-ice skating performance in division I men's hockey athletes.

Science.gov (United States)

Potteiger, Jeffrey A; Smith, Dean L; Maier, Mark L; Foster, Timothy S

2010-07-01

The purpose of this study was to examine relationships between laboratory tests and on-ice skating performance in division I men's hockey athletes. Twenty-one men (age 20.7 +/- 1.6 years) were assessed for body composition, isokinetic force production in the quadriceps and hamstring muscles, and anaerobic muscle power via the Wingate 30-second cycle ergometer test. Air displacement plethysmography was used to determine % body fat (%FAT), fat-free mass (FFM), and fat mass. Peak torque and total work during 10 maximal effort repetitions at 120 degrees .s were measured during concentric muscle actions using an isokinetic dynamometer. Muscle power was measured using a Monark cycle ergometer with resistance set at 7.5% of body mass. On-ice skating performance was measured during 6 timed 89-m sprints with subjects wearing full hockey equipment. First length skate (FLS) was 54 m, and total length skate (TLS) was 89 m with fastest and average skating times used in the analysis. Correlation coefficients were used to determine relationships between laboratory testing and on-ice performance. Subjects had a body mass of 88.8 +/- 7.8 kg and %FAT of 11.9 +/- 4.6. First length skate-Average and TLS-Average skating times were moderately correlated to %FAT ([r = 0.53; p = 0.013] and [r = 0.57; p = 0.007]) such that a greater %FAT was related to slower skating speeds. First length skate-Fastest was correlated to Wingate percent fatigue index (r = -0.48; p = 0.027) and FLS-Average was correlated to Wingate peak power per kilogram body mass (r = -0.43; p = 0.05). Laboratory testing of select variables can predict skating performance in ice hockey athletes. This information can be used to develop targeted and effective strength and conditioning programs that will improve on-ice skating speed.

Effect of Wearing the Elevation Training Mask on Aerobic Capacity, Lung Function, and Hematological Variables

Directory of Open Access Journals (Sweden)

John P. Porcari, Lauren Probst, Karlei Forrester, Scott Doberstein, Carl Foster, Maria L. Cress, Katharina Schmidt

2016-06-01

Full Text Available Altitude training and respiratory muscle training (RMT have been reported to improve performance in elite and well-trained athletes. Several devices (altitude and RMT have been developed to help athletes gain the competitive edge. The Elevation Training Mask 2.0 (ETM purportedly simulates altitude training and has been suggested to increase aerobic capacity (VO2max, endurance performance, and lung function. Twenty-four moderately trained subjects completed 6 weeks of high-intensity cycle ergometer training. Subjects were randomized into a mask (n = 12 or control (n = 12 group. Pre and post-training tests included VO2max, pulmonary function, maximal inspiration pressure, hemoglobin and hematocrit. No significant differences were found in pulmonary function or hematological variables between or within groups. There was a significant improvement in VO2max and PPO in both the control (13.5% and 9.9% and mask (16.5% and 13.6% groups. There was no difference in the magnitude of improvement between groups. Only the mask group had significant improvements in ventilatory threshold (VT (13.9%, power output (PO at VT (19.3%, respiratory compensation threshold (RCT (10.2%, and PO at RCT (16.4% from pre to post-testing. The trends for improvements in VT and PO at VT between groups were similar to improvements in RCT and PO at RCT, but did not reach statistical significance (VT p = 0.06, PO at VT p = 0.170. Wearing the ETM while participating in a 6-week high-intensity cycle ergometer training program does not appear to act as a simulator of altitude, but more like a respiratory muscle training device. Wearing the ETM may improve specific markers of endurance performance beyond the improvements seen with interval training alone.

Antiproliferative Activity of Phenylpropanoids Isolated from Lagotis brevituba Maxim.

Science.gov (United States)

Xiang, Yuan; Jing, Zhao; Haixia, Wang; Ruitao, Yu; Huaixiu, Wen; Zenggen, Liu; Lijuan, Mei; Yiping, Wang; Yanduo, Tao

2017-10-01

The aim of the present study was to evaluate the antiproliferative effect of phenylpropanoids isolated from the n-BuOH-soluble fraction of an ethanolic extract of Lagotis brevituba Maxim. The phenylpropanoids were identified as echinacoside, lagotioside, glucopyranosyl(1-6)martynoside, plantamoside, and verbascoside. Three of the compounds, lagotioside, glucopyranosyl(1-6)martynoside, and plantamoside, were isolated from L. brevituba for the first time. The antiproliferative activity of the isolates was evaluated in human gastric carcinoma (MGC-803), human colorectal carcinoma (HCT116), human hepatocellar carcinoma (HepG2), and human lung cancer (HCT116) cells using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Plantamoside showed promising activity against MGC-803 cells, with a half maximal inhibitory concentration value of 37.09 μM. The mechanism of the pro-apoptosis effect of plantamoside was then evaluated in MGC-803 cells. Changes in cell morphology, including disorganization of the architecture of actin microfilaments and formation of apoptotic bodies, together with cell cycle arrest in G2/M phases, were observed after treatment of plantamoside. The antiproliferative and pro-apoptotic effects were associated with a decrease in the ratio of Bcl-2/Bax and reduced mitochondrial membrane potential, which was accompanied by the release of reactive oxygen species and Ca 2+ into the cytoplasm. Taken together, the results indicated that plantamoside promotes apoptosis via a mitochondria-dependent mechanism. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Limit cycles from a cubic reversible system via the third-order averaging method

Directory of Open Access Journals (Sweden)

Linping Peng

2015-04-01

Full Text Available This article concerns the bifurcation of limit cycles from a cubic integrable and non-Hamiltonian system. By using the averaging theory of the first and second orders, we show that under any small cubic homogeneous perturbation, at most two limit cycles bifurcate from the period annulus of the unperturbed system, and this upper bound is sharp. By using the averaging theory of the third order, we show that two is also the maximal number of limit cycles emerging from the period annulus of the unperturbed system.

Applications and control of air conditioning systems using rapid cycling to modulate capacity

Energy Technology Data Exchange (ETDEWEB)

Poort, M.J.; Bullard, C.W. [Department of Mechanical and Industrial Engineering, Air Conditioning and Refrigeration Center, University of Illinois, 1206 W. Green St., Urbana, IL 61801 (United States)

2006-08-15

Rapid cycling the compressor of an air conditioning or refrigeration system can be used to modulate capacity, thus offering an alternative to a variable speed compressor. This paper explores design tradeoffs to optimize rapid cycling performance based on experimental results using two different evaporators and changing other components of an air conditioning system. Rapid cycling has inherent compressor lift penalties associated with larger mass flow rates, which need to be minimized. Preventing dryout (superheating) in the evaporator during the off cycle, a major penalty as cycles are lengthened, is also important. Evaporator dryout is minimized by increasing the refrigerant side area and reducing off cycle drainage. Combining a flash gas bypass with a suction line heat exchanger was found to maximize performance during the off cycle while allowing increased cycle lengths without incurring major penalties. (author)

The behavior of an opponent alters pacing decisions in 4-km cycling time trials.

Science.gov (United States)

Konings, Marco J; Schoenmakers, Patrick P J M; Walker, Andrew J; Hettinga, Florentina J

2016-05-01

The present study aimed to explore how athletes respond to different behaviors of their opponents. Twelve moderately to highly physically active participants with at least two years of cycling experience completed four 4-km time trials on a Velotron cycle ergometer. After a familiarization time trial (FAM), participants performed three experimental time trials in randomized order with no opponent (NO), a virtual opponent who started slower and finished faster compared to FAM (OP-SLOWFAST), or a virtual opponent who started faster and finished slower compared to FAM (OP-FASTSLOW). Repeated-measures ANOVAs (Ppower output, velocity and RPE. OP-SLOWFAST and OP-FASTSLOW were completed faster compared to NO (385.5±27.5, 385.0±28.6, and 390.6±29.3s, respectively). An interaction effect for condition×distance (F=3.944, Ppower outputs by the participants in the initial 750m compared to a slower starting opponent. The present study is the first to show that the behavior of an opponent affects pacing-related decisions in laboratory-controlled conditions. Our findings support the recently proposed interdependence of perception and action, and emphasize the interaction with the environment as an important determinant for an athlete's pacing decisions, especially during the initial stages of a race. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of Seat Tube Angle and Exercise Intensity on Muscle Activity Patterns in Cyclists

Science.gov (United States)

DUGGAN, WILL; DONNE, BERNARD; FLEMING, NEIL

2017-01-01

Previous studies have reported improved efficiency at steeper seat tube angle (STA) during ergometer cycling; however, neuromuscular mechanisms have yet to be fully determined. The current study investigated effects of STA on lower limb EMG activity at varying exercise intensities. Cyclists (n=11) were tested at 2 workloads; 160W and an individualised workload (IWL) equivalent to lactate threshold (TLac) minus 10%δ (derived from maximal incremental data), using 3 STA (70, 75 and 80°). Electromyographic data from Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) and Biceps Femoris (BF) were assessed. The timing and magnitude of activation were quantified and analysed using a two-way ANOVA. STA had significant (P pedal stroke is generated during the mid-section of the down-stroke, movement of the activation range of knee extensors into the predominantly power phase of the pedal stroke would potentially account for increased efficiency and decreased cardio-respiratory costs. Greater activity of bi-articular RF, in the first 108º of the crank cycle at IWL (80 vs. 70º) may more closely resemble the pelvic stabilising activity of RF in running biomechanics; and potentially explain the more effective transition from cycling to running reported in triathletes using steeper STA. PMID:29399245

Maximizing Entropy over Markov Processes

DEFF Research Database (Denmark)

Biondi, Fabrizio; Legay, Axel; Nielsen, Bo Friis

2013-01-01

The channel capacity of a deterministic system with confidential data is an upper bound on the amount of bits of data an attacker can learn from the system. We encode all possible attacks to a system using a probabilistic specification, an Interval Markov Chain. Then the channel capacity...... as a reward function, a polynomial algorithm to verify the existence of an system maximizing entropy among those respecting a specification, a procedure for the maximization of reward functions over Interval Markov Chains and its application to synthesize an implementation maximizing entropy. We show how...... to use Interval Markov Chains to model abstractions of deterministic systems with confidential data, and use the above results to compute their channel capacity. These results are a foundation for ongoing work on computing channel capacity for abstractions of programs derived from code....

Maximizing entropy over Markov processes

DEFF Research Database (Denmark)

Biondi, Fabrizio; Legay, Axel; Nielsen, Bo Friis

2014-01-01

The channel capacity of a deterministic system with confidential data is an upper bound on the amount of bits of data an attacker can learn from the system. We encode all possible attacks to a system using a probabilistic specification, an Interval Markov Chain. Then the channel capacity...... as a reward function, a polynomial algorithm to verify the existence of a system maximizing entropy among those respecting a specification, a procedure for the maximization of reward functions over Interval Markov Chains and its application to synthesize an implementation maximizing entropy. We show how...... to use Interval Markov Chains to model abstractions of deterministic systems with confidential data, and use the above results to compute their channel capacity. These results are a foundation for ongoing work on computing channel capacity for abstractions of programs derived from code. © 2014 Elsevier...

Changes in voluntary activation assessed by transcranial magnetic stimulation during prolonged cycling exercise.

Directory of Open Access Journals (Sweden)

Marc Jubeau

Full Text Available Maximal central motor drive is known to decrease during prolonged exercise although it remains to be determined whether a supraspinal deficit exists, and if so, when it appears. The purpose of this study was to evaluate corticospinal excitability and muscle voluntary activation before, during and after a 4-h cycling exercise. Ten healthy subjects performed three 80-min bouts on an ergocycle at 45% of their maximal aerobic power. Before exercise and immediately after each bout, neuromuscular function was evaluated in the quadriceps femoris muscles under isometric conditions. Transcranial magnetic stimulation was used to assess voluntary activation at the cortical level (VATMS, corticospinal excitability via motor-evoked potential (MEP and intracortical inhibition by cortical silent period (CSP. Electrical stimulation of the femoral nerve was used to measure voluntary activation at the peripheral level (VAFNES and muscle contractile properties. Maximal voluntary force was significantly reduced after the first bout (13 ± 9%, P<0.01 and was further decreased (25 ± 11%, P<0.001 at the end of exercise. CSP remained unchanged throughout the protocol. Rectus femoris and vastus lateralis but not vastus medialis MEP normalized to maximal M-wave amplitude significantly increased during cycling. Finally, significant decreases in both VATMS and VAFNES (∼ 8%, P<0.05 and ∼ 14%, P<0.001 post-exercise, respectively were observed. In conclusion, reductions in VAFNES after a prolonged cycling exercise are partly explained by a deficit at the cortical level accompanied by increased corticospinal excitability and unchanged intracortical inhibition. When comparing the present results with the literature, this study highlights that changes at the cortical and/or motoneuronal levels depend not only on the type of exercise (single-joint vs. whole-body but also on exercise intensity and/or duration.

HEALTH INSURANCE: CONTRIBUTIONS AND REIMBURSEMENT MAXIMAL

CERN Document Server

HR Division

2000-01-01

Affected by both the salary adjustment index on 1.1.2000 and the evolution of the staff members and fellows population, the average reference salary, which is used as an index for fixed contributions and reimbursement maximal, has changed significantly. An adjustment of the amounts of the reimbursement maximal and the fixed contributions is therefore necessary, as from 1 January 2000.Reimbursement maximalThe revised reimbursement maximal will appear on the leaflet summarising the benefits for the year 2000, which will soon be available from the divisional secretariats and from the AUSTRIA office at CERN.Fixed contributionsThe fixed contributions, applicable to some categories of voluntarily insured persons, are set as follows (amounts in CHF for monthly contributions):voluntarily insured member of the personnel, with complete coverage:815,- (was 803,- in 1999)voluntarily insured member of the personnel, with reduced coverage:407,- (was 402,- in 1999)voluntarily insured no longer dependent child:326,- (was 321...

On the maximal diphoton width

CERN Document Server

Salvio, Alberto; Strumia, Alessandro; Urbano, Alfredo

2016-01-01

Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal width into $\\gamma\\gamma$ that a neutral scalar can acquire through a loop of charged fermions or scalars as function of the maximal scale at which the theory holds, taking into account vacuum (meta)stability bounds. We show how an extra gauge symmetry can qualitatively weaken such bounds, and explore collider probes and connections with Dark Matter.

Maximized liquid radwaste volume reduction through a total integrated process: A new technology success story

International Nuclear Information System (INIS)

Rae, G.A.

1996-01-01

A fundamental nuclear industry goal is the minimization of the generation of radioactive waste. This goal has been dramatically reinforced over the past few years due to the spiraling increased costs of both commercial and DOE disposal. To assist in meeting these goals and reducing the industry's costs, NUKEM initiated a new technology program to maximize the reduction of liquid radwaste through the use of a systematic approach or TIPS (Total Integrated Process System). This concept evaluates the total life cycle of various technologies in a combination that results in the final waste form being minimized to the pure solids content of the waste stream. Additionally, it allows for a final waste form that maximizes the utilization of the waste package and is conditioned to be readily acceptable to additional processing to meet new waste form requirements at future disposal sites, should interim storage of the waste be required. The TIPS, although first introduced at commercial facilities, has broad applications for DOE's liquid waste streams

Validation of the Pulmonary Function System for Use on the International Space Station

Science.gov (United States)

McCleary, Frank A.; Moore, Alan D., Jr.; Hagan, R. Donald

2007-01-01

Aerobic deconditioning occurs during long duration space flight despite the use of exercise countermeasures (Convertino, 1996). As a part of International Space Station (ISS) medical operations, periodic tests designed to estimate aerobic capacity are performed to track changes in aerobic fitness and to determine the effectiveness of exercise countermeasures. These tests are performed prior to, during, and after missions of greater than 30 days in duration. Crewmembers selected for missions aboard the ISS perform a graded exercise test on a cycle ergometer approximately 270 days prior to their scheduled launch date in order to measure peak oxygen consumption (VO2PK) and peak heart rate (HRpk). Approximately 30 to 45 days prior to launch, crewmembers perform a submaximal cycle ergometer test at work rates set to elicit 25, 50 and 75% of their pre-flight VO2PK. This test, known as the Periodic Fitness Evaluation (PFE), serves as a baseline measure to which subsequent in-and post-flight exercise tests are compared. While onboard the ISS, crewmembers are normally scheduled to perform the PFE beginning with flight day (FD) 14 and every 30 days thereafter. The PFE is also conducted 5 and 30 days following flight. Using PFE data, aerobic fitness is estimated by quantifying the VO2 vs. HR relationship using linear regression and calculating the VO2 that would occur at the crewmember s previously measured HRpk. Currently, for data collected during flight, this technique assumes that the pre- vs. in-flight oxygen consumption per given cycle workload is similar. However, the validity of this assumption is based upon a sparse amount of data collected during the Skylab era (Michel, et al. 1977). The method of using heart rate and cycle ergometer work rates has been used to estimate aerobic fitness in normal gravity (Astrand and Ryhming, 1954; Lee, 1993). Due to spaceflight induced physiological alterations, such as shifts in extracellular fluid (e.g. plasma) volume, this method

Optimization of a regenerative Brayton cycle by maximization of a newly defined second law efficiency

NARCIS (Netherlands)

Haseli, Y.

2013-01-01

The idea is to find out whether 2nd law efficiency optimization may be a suitable trade-off between maximum work output and maximum 1st law efficiency designs for a regenerative gas turbine engine operating on the basis of an open Brayton cycle. The primary emphasis is placed on analyzing the ideal

Power and efficiency optimization for combined Brayton and inverse Brayton cycles

International Nuclear Information System (INIS)

Zhang Wanli; Chen Lingen; Sun Fengrui

2009-01-01

A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, combustion inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative pressure drops associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the compressor pressure ratio of the top cycle are derived with the 11 pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the compressor inlet pressure of the bottom cycle, the air mass flow rate and the distribution of pressure losses along the flow path. It is shown that the power output has a maximum with respect to the compressor inlet pressure of the bottom cycle, the air mass flow rate or any of the overall pressure drops, and the maximized power output has an additional maximum with respect to the compressor pressure

Effects of inspiratory muscle training on dynamic hyperinflation in patients with COPD

Directory of Open Access Journals (Sweden)

Petrovic M

2012-11-01

Full Text Available Milos Petrovic,1 Michael Reiter,2 Harald Zipko,3 Wolfgang Pohl,1 Theodor Wanke11Pulmonary Department and Karl Landsteiner Institute for Clinical and Experimental Pulmology, Hietzing Hospital, Vienna, Austria; 2Department of Respiratory and Critical Care Medicine, Otto Wagner Hospital, Vienna, Austria; 3FH Campus Vienna, University of Applied Sciences – Health Department, Vienna, AustriaAbstract: Dynamic hyperinflation has important clinical consequences in patients with chronic obstructive pulmonary disease (COPD. Given that most of these patients have respiratory and peripheral muscle weakness, dyspnea and functional exercise capacity may improve as a result of inspiratory muscle training (IMT. The aim of the study was to analyze the effects of IMT on exercise capacity, dyspnea, and inspiratory fraction (IF during exercise in patients with COPD. Daily inspiratory muscle strength and endurance training was performed for 8 weeks in 10 patients with COPD GOLD II and III. Ten patients with COPD II and III served as a control group. Maximal inspiratory pressure (Pimax and endurance time during resistive breathing maneuvers (tlim served as parameter for inspiratory muscle capacity. Before and after training, the patients performed an incremental symptom limited exercise test to maximum and a constant load test on a cycle ergometer at 75% of the peak work rate obtained in the pretraining incremental test. ET was defined as the duration of loaded pedaling. Following IMT, there was a statistically significant increase in inspiratory muscle performance of the Pimax from 7.75 ± 0.47 to 9.15 ± 0.73 kPa (P < 0.01 and of tlim from 348 ± 54 to 467 ± 58 seconds (P < 0.01. A significant increase in IF, indicating decreased dynamic hyperinflation, was observed during both exercise tests. Further, the ratio of breathing frequency to minute ventilation (bf/V'E decreased significantly, indicating an improved breathing pattern. A significant decrease in

Myocardial functional responses do not contribute to maximal exercise performance in the heat.

Science.gov (United States)

Smith, Denise L; DeBlois, Jacob P; Wharton, Margaret; Rowland, Thomas

2015-01-01

Both the extent and means by which maximal oxygen uptake ([Formula: see text]) is depressed by elevated ambient temperature are uncertain. Particularly, information is currently unavailable regarding the possible influence of alterations in myocardial function on [Formula: see text] and performance during exercise in the heat. This study investigated the effects of environmental heat on [Formula: see text], peak work capacity, and myocardial function during a standard, progressive cycle test to exhaustion. Twelve euhydrated men (aged 20.7 ± 1.7 years) performed a maximal cycle test in an environmental chamber in both heat stress [35°C, 30% relative humidity (RH)] and temperate (20°C, 30% RH) conditions with measurement of standard gas exchange variables, core temperature, and echocardiographic measures of cardiac function. A small but statistically significant reduction of peak work capacity was observed in the heat stress versus temperate conditions (253 ± 30 and 259 ± 30 W, respectively, p = 0.02). Mean [Formula: see text] was not statistically different in the two conditions (p = 0.16) but values were 3.4% lower in the heat, and 9 of 12 participants demonstrated lower values in the heat stress trial. No differences in responses of heart rate, cardiac output, stroke volume, core temperature, hydration status, or myocardial systolic or diastolic function were observed between the two conditions, but perceived body temperature was higher in the heat. The small, negative impact of heat on exercise performance and [Formula: see text] could not be explained by disturbances in myocardial functional responses to exercise in young adult males.

The anti-tumor effect and biological activities of the extract JMM6 from the stem-barks of the Chinese Juglans mandshurica Maxim on human hepatoma cell line BEL-7402.

Science.gov (United States)

Zhang, Yongli; Cui, Yuqiang; Zhu, Jiayong; Li, Hongzhi; Mao, Jianwen; Jin, Xiaobao; Wang, Xiangsheng; Du, Yifan; Lu, Jiazheng

2013-01-01

Juglans mandshurica Maxim is a traditional herbal medicines in China, and its anti-tumor bioactivities are of research interest. Bioassay-guided fractionation method was employed to isolate anti-tumor compounds from the stem barks of the Juglans mandshurica Maxim. The anti-tumor effect and biological activities of the extracted compound JMM6 were studied in BEL-7402 cells by MTT, Cell cycle analysis, Hoechst 33342 staining, Annexin V-FITC/PI assay and Detection of mitochondrial membrane potential (ΔΨm). After treatment with the JMM6, the growth of BEL-7402 cells was inhibited and cells displayed typical morphological apoptotic characteristics. Further investigations revealed that treatment with JMM6 mainly caused G2/M cell cycle arrest and induced apoptosis in BEL-7402 cells. To evaluate the alteration of mitochondria in JMM6 induced apoptosis. The data showed that JMM6 decreased significantly the ΔΨm, causing the depolarization of the mitochondrial membrane. Our results show that the JMM6 will have a potential advantage of anti-tumor, less harmful to normal cells. This paper not only summarized the JMM6 pick-up technology from Juglans mandshurica Maxim and biological characteristic, but also may provide further evidence to exploit the potential medicine compounds from the stem-barks of the Chinese Juglans mandshurica Maxim.

On Longest Cycles in Essentially 4-Connected Planar Graphs

Directory of Open Access Journals (Sweden)

Fabrici Igor

2016-08-01

Full Text Available A planar 3-connected graph G is essentially 4-connected if, for any 3-separator S of G, one component of the graph obtained from G by removing S is a single vertex. Jackson and Wormald proved that an essentially 4-connected planar graph on n vertices contains a cycle C such that . For a cubic essentially 4-connected planar graph G, Grünbaum with Malkevitch, and Zhang showed that G has a cycle on at least ¾ n vertices. In the present paper the result of Jackson and Wormald is improved. Moreover, new lower bounds on the length of a longest cycle of G are presented if G is an essentially 4-connected planar graph of maximum degree 4 or G is an essentially 4-connected maximal planar graph.

High-intensity sprint fatigue does not alter constant-submaximal velocity running mechanics and spring-mass behavior.

Science.gov (United States)

Morin, Jean-Benoit; Tomazin, Katja; Samozino, Pierre; Edouard, Pascal; Millet, Guillaume Y

2012-04-01

We investigated the changes in constant velocity spring-mass behavior after high intensity sprint fatigue in order to better interpret the results recently reported after ultra-long distance (ULD) exercises. Our hypothesis was that after repeated sprints (RS), subjects may likely experience losses of force such as after ULD, but the necessity to modify their running pattern to attenuate the overall impact at each step (such as after ULD) may not be present. Eleven male subjects performed four sets of five 6-s sprints with 24-s recovery between sprints and 3 min between sets, on a sprint treadmill and on a bicycle ergometer. For each session, their running mechanics and spring-mass characteristics were measured at 10 and 20 km h(-1) on an instrumented treadmill before and after RS. Two-way (period and velocity) ANOVAs showed that high-intensity fatigue did not induce any change in the constant velocity running pattern at low or high velocity, after both running and cycling RS, despite significant decreases (P < 0.001) in maximal power (-27.1 ± 8.2% after running RS and -15.4 ± 11.5 % after cycling RS) and knee extensors maximal voluntary force (-18.8 ± 6.7 % after running RS and -15.0 ± 7.6 % after cycling RS). These results bring indirect support to the hypothesis put forward in recent ULD studies that the changes in running mechanics observed after ULD are likely not related to the decrease in strength capabilities, but rather to the necessity for subjects to adopt a protective running pattern.

CONTINUOUS MONITORING OF LACTATE DURING EXERCISE IN HUMANS USING SUBCUTANEOUS AND TRANSCUTANEOUS MICRODIALYSIS

NARCIS (Netherlands)

DEBOER, J; PLIJTERGROENDIJK, H; VISSER, KR; MOOK, GA; KORF, J

1994-01-01

We have evaluated the possibility of monitoring the plasma lactate concentration in human volunteers during cycle ergometer exercise using subcutaneous and transcutaneous microdialysis. In transcutaneous microdialysis, the relative increase in dialysate lactate concentration exceeded that of plasma

Design and optimization of a novel organic Rankine cycle with improved boiling process

DEFF Research Database (Denmark)

Andreasen, Jesper Graa; Larsen, U.; Knudsen, Thomas

2015-01-01

to improve the boiling process. Optimizations are carried out for eight hydrocarbon mixtures for hot fluid inlet temperatures at 120 °C and 90 °C, using a genetic algorithm to determine the cycle conditions for which the net power output is maximized. The most promising mixture is an isobutane....../pentane mixture which, for the 90 °C hot fluid inlet temperature case, achieves a 14.5% higher net power output than an optimized organic Rankine cycle using the same mixture. Two parameter studies suggest that optimum conditions for the organic split-cycle are when the temperature profile allows the minimum...

Physiological characteristics of an aging Olympic athlete.

Science.gov (United States)

Nybo, Lars; Schmidt, Jakob F; Fritzdorf, Stephen; Nordsborg, Nikolai B

2014-11-01

To investigate the physiological basis of continued world-class performance of a world-class rower who won medals (three gold and two bronze) at five consecutive Olympic Games. From the age of 19 to 40 yr, maximal oxygen uptake (VO2 max), peak HR, blood lactate, and rowing ergometer performance were assessed annually. During the first years of his elite career (from age 19 to 24), VO2 max increased from 5.5 to approximately 5.9 L · min(-1) (78 mL · min(-1) · kg(-1)) and his average power during 6-min maximal rowing increased from 420 to approximately 460 W. Although his HRmax declined by approximately 20 bpm during the 20-yr period, maximal aerobic power, evaluated both as VO2 max and 6-min test performance, was maintained until the age of 40. Furthermore, peak lactate levels remained unchanged and average power outputs during 10-s, 60-s, and 60-min ergometer tests were all maintained at approximately 800 W, approximately 700 W, and approximately 350 W, respectively, indicating that he was able to preserve both aerobic and anaerobic exercise performances. Echocardiographic analyses revealed a left ventricular mass of 198 g and left ventricular end-diastolic diameter of 5.8 cm. This longitudinal case indicates that until the age of 40 yr, a steady increase in the oxygen pulse may have compensated for the significant decline in the maximal heart frequency. Furthermore, the maintenance of aerobic and anaerobic exercise capacities allowed this Olympic athlete to compete at the highest level for almost two decades.

A Criterion to Identify Maximally Entangled Four-Qubit State

International Nuclear Information System (INIS)

Zha Xinwei; Song Haiyang; Feng Feng

2011-01-01

Paolo Facchi, et al. [Phys. Rev. A 77 (2008) 060304(R)] presented a maximally multipartite entangled state (MMES). Here, we give a criterion for the identification of maximally entangled four-qubit states. Using this criterion, we not only identify some existing maximally entangled four-qubit states in the literature, but also find several new maximally entangled four-qubit states as well. (general)

Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

Directory of Open Access Journals (Sweden)

Carolin Stangier, Thomas Abel, Julia Mierau, Wildor Hollmann, Heiko K. Strüder

2016-03-01

Full Text Available The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour for 8 weeks. Training intensity was determined within non-specific (cycling or running and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m and one non-specific (30s cycling or 200m running all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa and glucose (BGL 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak was significantly increased (+17%; p = 0.01 in both groups and highly correlated with the sprint performance (r = -0.71. BLa values decreased significantly (-18%, p = 0.02 after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04 in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group.

Metabolic Responses to Sago and Soy Supplementations during Endurance Cycling Performance in the Heat

Directory of Open Access Journals (Sweden)

Daniel Tarmast

2017-10-01

Full Text Available This study examined the effects of Sago (Sa, Soy (So, combined iso–caloric Sago+Soy (SS supplementations during cycling on metabolic responses as compared to placebo (P in the heat (31℃, 70% relative humidity. Twelve well–trained male cyclists (Age: 19.0±5.6 yr, Height: 170.8±7.6 cm, Wight: 60.1±11.2 kg, and VO2max: 56.5±6.5 mL.kg-1.min-1 participated in four experimental trials. The design of the trials was a randomized single–blind, placebo–controlled crossover trail comprising 90 min of steady–state cycling on an ergometer at 60% of VO2max followed by a 20–km time trial performance (TT. The participants of the study were supplemented 5 times at 0, 20, 40, 60, and 80 minutes during the steady–state cycling. Sa, So, and SS supplements provided 7.5% Sago, 7.5% Soy, and 6.0% Sago + 1.5% Soy respectively. Plasma glucose concentrations (PG reached a peak at 60 min after ingestion of Sa and SS as compared to baseline. At the end of the TT, PG reduced significantly to the baseline level. Plasma insulin concentrations (PI increased in all trials, but reduced gradually to the baseline level. The concentration of plasma free fatty acids (FFA increased gradually during the steady–state cycling and TT, and FFA was significantly higher in the P and So than the Sa and SS trials. At the end of the steady–state cycling, the plasma lactate concentration (LACT reached its lowest concentrations and at the end of the TT was enhanced significantly in all trials. These results suggest that sago and soy supplements increase the PG and PI during endurance exercise in the heat. These data add to the growing body of knowledge concerning endurance athletes’ glycemic and insulinemic responses to carbohydrate consumptions during exercise in the heat.

Selection and optimization of pure and mixed working fluids for low grade heat utilization using organic Rankine cycles

DEFF Research Database (Denmark)

Andreasen, Jesper Graa; Larsen, Ulrik; Knudsen, Thomas

2014-01-01

We present a generic methodology for organic Rankine cycle optimization, where the working fluid is included as an optimization parameter, in order to maximize the net power output of the cycle. The method is applied on two optimization cases with hot fluid inlet temperatures at 120°C and 90°C. P...

Vacua of maximal gauged D=3 supergravities

International Nuclear Information System (INIS)

Fischbacher, T; Nicolai, H; Samtleben, H

2002-01-01

We analyse the scalar potentials of maximal gauged three-dimensional supergravities which reveal a surprisingly rich structure. In contrast to maximal supergravities in dimensions D≥4, all these theories possess a maximally supersymmetric (N=16) ground state with negative cosmological constant Λ 2 gauged theory, whose maximally supersymmetric groundstate has Λ = 0. We compute the mass spectra of bosonic and fermionic fluctuations around these vacua and identify the unitary irreducible representations of the relevant background (super)isometry groups to which they belong. In addition, we find several stationary points which are not maximally supersymmetric, and determine their complete mass spectra as well. In particular, we show that there are analogues of all stationary points found in higher dimensions, among them are de Sitter (dS) vacua in the theories with noncompact gauge groups SO(5, 3) 2 and SO(4, 4) 2 , as well as anti-de Sitter (AdS) vacua in the compact gauged theory preserving 1/4 and 1/8 of the supersymmetries. All the dS vacua have tachyonic instabilities, whereas there do exist nonsupersymmetric AdS vacua which are stable, again in contrast to the D≥4 theories

Research on the Development of the Supercritical CO{sub 2} Dual Brayton Cycle

Energy Technology Data Exchange (ETDEWEB)

Baik, Young-Jin; Na, Sun Ik; Cho, Junhyun; Shin, Hyung-Ki; Lee, Gilbong [Korea Institute of Energy Research (KIER), Daejeon (Korea, Republic of)

2016-10-15

Because of the growing interest in supercritical carbon dioxide power cycle technology owing to its potential enhancement in compactness and efficiency, supercritical carbon dioxide cycles have been studied in the fields of nuclear power, concentrated solar power (CSP), and fossil fuel power generation. This study introduces the current status of the research project on the supercritical carbon dioxide power cycle by Korea Institute of Energy Research (KIER). During the first phase of the project, the un-recuperated supercritical Brayton cycle test loop was built and tested. In phase two, researchers are designing and building a supercritical carbon dioxide dual Brayton cycle, which utilizes two turbines and two recuperators. Under the simulation condition considered in this study, it was confirmed that the design parameter has an optimal value for maximizing the net power in the supercritical carbon dioxide dual cycle.

Jumping Abilities and Power-Velocity Relationship in Judo Athletes: Comparative Analysis Among Age Categories

Directory of Open Access Journals (Sweden)

Buśko Krzysztof

2015-06-01

Full Text Available Purpose. The aim of the study was to examine age differences in the maximal power and height of rise of the body mass centre measured in spike jump (SPJ and counter-movement jump (CMJ, and power-velocity relationship of lower extremities between cadet and U23 age class judo athletes. Methods. Seven cadets (age 16.6 ± 0.7 years and eight U23 age class (21.3 ± 1.4 years Polish judoists took part in the study. The maximal power and height of jump were measured at SPJ and CMJ jumps. Power- velocity relations (P-v were determined from 5 maximal cycle ergometer exercise bouts at increasing external loads equal to 2.5, 5.0, 7.5, 10.0 and 12.5% of body weight (BW. Results. Cadet judoists had a significantly smaller maximal power output (11.56 ± 1.21 W ・ kg-1 than U23 athletes (12.69 ± 0.67 W ・ kg-1. The optimal velocity was similar in both group (119.3 ± 16.0 rpm and 119.6 ± 15.5 rpm, respectively. Significant age differences were founded between the cadet and U23 athletes for power output at external load equal 12.5% BW. Cadet judoists generated insignificantly lower maximal power in CMJ and SPJ than U23 judo athletes with except of the absolute maximal power in SPJ. The age difference was observed in height of CMJ. Conclusions. Based on the characteristics of F-v curve we can see in which direction follow the effects of training. Application of CMJ and SPJ in jumping test allows to assess changes in neuromuscular coordination. The use of the both methods give better information to optimal training control.

Effects of synchronous versus asynchronous mode of propulsion on wheelchair basketball sprinting.

Science.gov (United States)

Faupin, Arnaud; Borel, Benoit; Meyer, Christophe; Gorce, Philippe; Watelain, Eric

2013-11-01

This study aimed to first investigate synchronous (SYN) versus asynchronous (ASY) mode of propulsion and, second, investigate the wheel camber effects on sprinting performance as well as temporal parameters. Seven wheelchair basketball players performed four maximal eight-second sprints on a wheelchair ergometer. They repeated the test according to two modes of propulsion (SYN and ASY) and two wheel cambers (9° and 15°). The mean maximal velocity and push power output was greater in the synchronous mode compared to the asynchronous mode for both camber angles. However, the fluctuation in the velocity profile is inferior for ASY versus SYN mode for both camber angles. Greater push time/cycle time (Pt/Ct) and arm frequency (AF) for synchronous mode versus asynchronous mode and inversely, lesser Ct and rest time (Rt) values for the synchronous mode, for which greater velocity were observed. SYN mode leads to better performance than ASY mode in terms of maximal propulsion velocity. However, ASY propulsion allows greater continuity of the hand-rim force application, reducing fluctuations in the velocity profile. The camber angle had no effect on ASY and SYN mean maximal velocity and push power output. The study of wheelchair propulsion strategies is important for better understanding physiological and biomechanical impacts of wheelchair propulsion for individuals with disabilities. From a kinematical point of view, this study highlights synchronous mode of propulsion to be more efficient, with regards to mean maximal velocity reaching during maximal sprinting exercises. Even if this study focuses on well-trained wheelchair athletes, results from this study could complement the knowledge on the physiological and biomechanical adaptations to wheelchair propulsion and therefore, might be interesting for wheelchair modifications for purposes of rehabilitation.

Validity and reliability of the look Keo power pedal system for measuring power output during incremental and repeated sprint cycling.

Science.gov (United States)

Sparks, S Andy; Dove, Benjamin; Bridge, Craig A; Midgely, Adrian W; McNaughton, Lars R

2015-01-01

Power meters have traditionally been integrated into the crank set, but several manufacturers have designed new systems located elsewhere on the bike, such as inside the pedals. This study aimed to determine the validity and reliability of the Keo power pedals during several laboratory cycling tasks. Ten active male participants (mean ± SD age 34.0 ± 10.6 y, height 1.77 ± 0.04 m, body mass 76.5 ± 10.7 kg) familiar with laboratory cycling protocols completed this study. Each participant was required to complete 2 laboratory cycling trials on an SRM ergometer (SRM, Germany) that was also fitted with the Keo power pedals (Look, France). The trials consisted of an incremental test to exhaustion followed by 10 min rest and then three 10-s sprint tests separated by 3 min of cycling at 100 W. Over power ranges of 75 to 1147 W, the Keo power-pedal system produced typical error values of 0.40, 0.21, and 0.21 for the incremental, sprint, and combined trials, respectively, compared with the SRM. Mean differences of 21.0 and 18.6 W were observed between trials 1 and 2 with the Keo system in the incremental and combined protocols, respectively. In contrast, the SRM produced differences of 1.3 and 0.6 W for the same protocols. The power data from the Keo power pedals should be treated with some caution given the presence of mean differences between them and the SRM. Furthermore, this is exacerbated by poorer reliability than that of the SRM power meter.

A Conceptual Study of Using an Isothermal Compressor on a Supercritical CO2 Cycle for Various Nuclear Applications

International Nuclear Information System (INIS)

Heo, Jin Young; Lee, Jeong Ik

2017-01-01

In order to accelerate the deployment of cleaner and safer energy sources, further development of such advanced nuclear power systems is necessary. By aiming to have higher efficiency, lower costs, and reduced system size, next-generation nuclear reactors can have greater advantages which will justify their adoption. Many research efforts focus on these objectives to also propose new concepts and technologies to improve the present state of the art. To maximize the benefits of advanced reactor designs, the supercritical CO 2 (S-CO 2 ) power cycle can be adopted to enhance the performance of the power conversion systems. The potential of replacing the conventional power block with the S-CO 2 power cycle can increase the cycle efficiency and also reduce its overall system size. The potential of using the S-CO 2 power cycles in advanced nuclear reactors can be further improved by adopting an isothermal compressor to the cycle layout. This paper attempts to improve the cycle layout by replacing the conventional compressor with an isothermal compressor, of which its potential in the S-CO 2 power cycle is conceptually being evaluated. An isothermal compressor minimizes compression work and further reduces the system size by having smaller heat exchanger requirements. The study includes cycle optimization maximizing cycle efficiency with respect to different cycle design parameters. The S-CO 2 iso-Brayton cycle layouts have been effective in improving the cycle efficiencies of the next-generation nuclear reactors. By using the isothermal compressor, the net efficiency can be improved by 8% points for the simple recuperated cycle layout, and 5% points for the recompression cycle layout. It is also noted that the estimated UA values required for the iso-Brayton cycle layouts are almost the same or less compared to those of the reference cycle layouts.

Aerobic capacity explains physical functioning and participation in patients with multiple sclerosis-related fatigue

OpenAIRE

Emma Rosalie Driehuis; Lizanne Eva van den Akker; Vincent de Groot; Heleen Beckerman

2018-01-01

Objective: To investigate whether aerobic capacity explains the level of self-reported physical activity, physical functioning, and participation and autonomy in daily living in persons with multiple sclerosis-related fatigue. Design: A cross-sectional study. Patients: Sixty-two participants with multiple sclerosis-related fatigue. Methods: Aerobic capacity was measured with a leg ergometer and was expressed as maximal oxygen uptake (VO2max, in ...

Sex differences in autonomic function following maximal exercise.

Science.gov (United States)

Kappus, Rebecca M; Ranadive, Sushant M; Yan, Huimin; Lane-Cordova, Abbi D; Cook, Marc D; Sun, Peng; Harvey, I Shevon; Wilund, Kenneth R; Woods, Jeffrey A; Fernhall, Bo

2015-01-01

Heart rate variability (HRV), blood pressure variability, (BPV) and heart rate recovery (HRR) are measures that provide insight regarding autonomic function. Maximal exercise can affect autonomic function, and it is unknown if there are sex differences in autonomic recovery following exercise. Therefore, the purpose of this study was to determine sex differences in several measures of autonomic function and the response following maximal exercise. Seventy-one (31 males and 40 females) healthy, nonsmoking, sedentary normotensive subjects between the ages of 18 and 35 underwent measurements of HRV and BPV at rest and following a maximal exercise bout. HRR was measured at minute one and two following maximal exercise. Males have significantly greater HRR following maximal exercise at both minute one and two; however, the significance between sexes was eliminated when controlling for VO2 peak. Males had significantly higher resting BPV-low-frequency (LF) values compared to females and did not significantly change following exercise, whereas females had significantly increased BPV-LF values following acute maximal exercise. Although males and females exhibited a significant decrease in both HRV-LF and HRV-high frequency (HF) with exercise, females had significantly higher HRV-HF values following exercise. Males had a significantly higher HRV-LF/HF ratio at rest; however, both males and females significantly increased their HRV-LF/HF ratio following exercise. Pre-menopausal females exhibit a cardioprotective autonomic profile compared to age-matched males due to lower resting sympathetic activity and faster vagal reactivation following maximal exercise. Acute maximal exercise is a sufficient autonomic stressor to demonstrate sex differences in the critical post-exercise recovery period.

Eccentric exercise decreases maximal insulin action in humans

DEFF Research Database (Denmark)

Asp, Svend; Daugaard, J R; Kristiansen, S

1996-01-01

subjects participated in two euglycaemic clamps, performed in random order. One clamp was preceded 2 days earlier by one-legged eccentric exercise (post-eccentric exercise clamp (PEC)) and one was without the prior exercise (control clamp (CC)). 2. During PEC the maximal insulin-stimulated glucose uptake...... for all three clamp steps used (P maximal activity of glycogen synthase was identical in the two thighs for all clamp steps. 3. The glucose infusion rate (GIR......) necessary to maintain euglycaemia during maximal insulin stimulation was lower during PEC compared with CC (15.7%, 81.3 +/- 3.2 vs. 96.4 +/- 8.8 mumol kg-1 min-1, P maximal...

Oxidative stress and nitrite dynamics under maximal load in elite athletes: relation to sport type.

Science.gov (United States)

Cubrilo, Dejan; Djordjevic, Dusica; Zivkovic, Vladimir; Djuric, Dragan; Blagojevic, Dusko; Spasic, Mihajlo; Jakovljevic, Vladimir

2011-09-01

Maximal workload in elite athletes induces increased generation of reactive oxygen/nitrogen species (RONS) and oxidative stress, but the dynamics of RONS production are not fully explored. The aim of our study was to examine the effects of long-term engagement in sports with different energy requirements (aerobic, anaerobic, and aerobic/anaerobic) on oxidative stress parameters during progressive exercise test. Concentrations of lactates, nitric oxide (NO) measured through stabile end product-nitrites (NO(2) (-)), superoxide anion radical (O(2) (•-)), and thiobarbituric reactive substances (TBARS) as index of lipid peroxidation were determined in rest, after maximal workload, and at 4 and 10th min of recovery in blood plasma of top level competitors in rowing, cycling, and taekwondo. Results showed that sportmen had similar concentrations of lactates and O(2) (•-) in rest. Nitrite concentrations in rest were the lowest in taekwondo fighters, while rowers had the highest levels among examined groups. The order of magnitude for TBARS level in the rest was bicycling > taekwondo > rowing. During exercise at maximal intensity, the concentration of lactate significantly elevated to similar levels in all tested sportsmen and they were persistently elevated during recovery period of 4 and 10 min. There were no significant changes in O(2) (•-), nitrite, and TBARS levels neither at the maximum intensity of exercise nor during the recovery period comparing to the rest period in examined individuals. Our results showed that long term different training strategies establish different basal nitrites and lipid peroxidation levels in sportmen. However, progressive exercise does not influence basal nitrite and oxidative stress parameters level neither at maximal load nor during the first 10 min of recovery in sportmen studied.

Case study An elite runner with cerebral palsy: cost of running ...

African Journals Online (AJOL)

threshold (VT), running economy (often measured as cost of running (CR) as VO2 in .... treadmill belt at 1% elevation to mimic wind resistance. Respiratory ... steady state (50% peak power output) on the same cycle ergometer. (Lode Excalibur ...

Maximize x(a - x)

Science.gov (United States)

Lange, L. H.

1974-01-01

Five different methods for determining the maximizing condition for x(a - x) are presented. Included is the ancient Greek version and a method attributed to Fermat. None of the proofs use calculus. (LS)

A complete geothermal energy cycle with heat pumps and hybrid HVAC systems for the city of Denizli, Turkey

Energy Technology Data Exchange (ETDEWEB)

Eltez, M. [Ege Univ., Izmir (Turkey). Mechanical Engineering Dept.; Kilkis, I.B. [Heatway Radiant Floors and Snowmelting, Springfield, MO (United States)]|[Middle East Technical Univ., Ankara (Turkey)

1995-12-31

This paper discusses general aspects of maximizing geofluid effectiveness by employing hybrid cycle plants coupled to district HVAC systems. Alternative and new techniques in space heating and cooling are also discussed. A case study is presented for the district HVAC system for the city of Denizli in Turkey. Results are compared with an open-cycle, open-loop system.

Cardiorespiratory optimal point during exercise testing as a predictor of all-cause mortality.

Science.gov (United States)

Ramos, Plínio S; Araújo, Claudio Gil S

2017-04-01

The cardiorespiratory optimal point (COP) is a novel index, calculated as the minimum oxygen ventilatory equivalent (VE/VO 2 ) obtained during cardiopulmonary exercise testing (CPET). In this study we demonstrate the prognostic value of COP both independently and in combination with maximum oxygen consumption (VO 2 max) in community-dwelling adults. Maximal cycle ergometer CPET was performed in 3331 adults (66% men) aged 40-85 years, healthy (18%) or with chronic disease (81%). COP cut-off values of 30 were selected based on the log-rank test. Risk discrimination was assessed using COP as an independent predictor and combined with VO 2 max. Median follow-up was 6.4 years (7.1% mortality). Subjects with COP >30 demonstrated increased mortality compared to those with COP 30 of 3.72 (95% CI 1.98-6.98; p30, either independently or in combination with low VO 2 max, is a good predictor of all-cause mortality in community-dwelling adults (healthy or with chronic disease). COP is a submaximal prognostic index that is simple to obtain and adds to CPET assessment, especially for adults unable or unwilling to achieve maximal exercise. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Cordyceps militaris improves tolerance to high intensity exercise after acute and chronic supplementation

Science.gov (United States)

Hirsch, Katie R.; Smith-Ryan, Abbie E.; Roelofs, Erica J.; Trexler, Eric T.; Mock, Meredith G.

2016-01-01

To determine the effects of a mushroom blend containing cordyceps militaris on high intensity exercise after 1- and 3-weeks of supplementation. Twenty-eight individuals (Mean ± SD; Age=22.7 ± 4.1 yrs; Height=175.4 ± 8.7 cm; Weight=71.6 ± 12.0 kg) participated in this randomized, repeated measures, double-blind, placebo-controlled design. Maximal oxygen consumption (VO2max), time to exhaustion (TTE), and ventilatory threshold (VT) were measured during a maximal graded exercise test on a cycle ergometer. Relative peak power output (RPP), average power output (AvgP), and percent drop (%drop) were recorded during a 3-minute maximal cycle test with resistance at 4.5% body weight. Subjects consumed 4 g·d−1 mushroom blend (MR) or maltodextrin (PL) for 1 week. Ten volunteers supplemented for an additional 2 weeks. Exercise tests were separated by at least 48-hours and repeated following supplementation periods. One week of supplementation elicited no significant time × treatment interaction for VO2max (p=0.364), VT (p=0.514), TTE (p=0.540), RPP (p=0.134), AvgP (p=0.398), or %drop (p=0.823). After 3-weeks, VO2max significantly improved (p=0.042) in MR (+4.8 ml·kg−1·min−1), but not PL (+0.9 ml·kg−1·min−1). Analysis of 95% confidence intervals revealed significant improvements in TTE after 1- (+28.1 s) and 3-weeks (+69.8 s) in MR, but not PL, with additional improvements in VO2max (+4.8 ml·kg−1·min−1) and VT (+0.7 l·min−1) after 3-weeks. Acute supplementation with a cordyceps militaris containing mushroom blend may improve tolerance to high intensity exercise; greater benefits may be elicited with consistent chronic supplementation. PMID:27408987

Estimating Hemodynamic Responses to the Wingate Test Using Thoracic Impedance

Directory of Open Access Journals (Sweden)

Todd A. Astorino, Curtis Bovee, Ashley DeBoe

2015-12-01

Full Text Available Techniques including direct Fick and Doppler echocardiography are frequently used to assess hemodynamic responses to exercise. Thoracic impedance has been shown to be a noninvasive alternative to these methods for assessing these responses during graded exercise to exhaustion, yet its feasibility during supramaximal bouts of exercise is relatively unknown. We used thoracic impedance to estimate stroke volume (SV and cardiac output (CO during the Wingate test (WAnT and compared these values to those from graded exercise testing (GXT. Active men (n = 9 and women (n = 7 (mean age = 24.8 ± 5.9 yr completed two Wingate tests and two graded exercise tests on a cycle ergometer. During exercise, heart rate (HR, SV, and CO were continuously estimated using thoracic impedance. Repeated measures analysis of variance was used to identify potential differences in hemodynamic responses across protocols. Results: Maximal SV (138.6 ± 37.4 mL vs. 135.6 ± 26.9 mL and CO (24.5 ± 6.1 L·min-1 vs. 23.7 ± 5.1 L·min-1 were similar (p > 0.05 between repeated Wingate tests. Mean maximal HR was higher (p < 0.01 for GXT (185 ± 7 b·min-1 versus WAnT (177 ± 11 b·min-1, and mean SV was higher in response to WAnT (137.1 ± 32.1 mL versus GXT (123.0 ± 32.0 mL, leading to similar maximal cardiac output between WAnT and GXT (23.9 ± 5.6 L·min-1 vs. 22.5 ± 6.0 L·min-1. Our data show no difference in hemodynamic responses in response to repeated administrations of the Wingate test. In addition, the Wingate test elicits similar cardiac output compared to progressive cycling to VO2max.

Glycopyrrolate abolishes the exercise-induced increase in cerebral perfusion in humans

DEFF Research Database (Denmark)

Seifert, Thomas; Fisher, James P; Young, Colin N

2010-01-01

(mean) during ergometer cycling (n = 8). Separate, randomized and counterbalanced trials were performed in control (no drug) conditions and following muscarinic cholinergic receptor blockade by glycopyrrolate. Glycopyrrolate increased resting heart rate from approximately 60 to approximately 110 beats min(-1...

Part-load performance of a high temperature Kalina cycle

International Nuclear Information System (INIS)

Modi, Anish; Andreasen, Jesper Graa; Kærn, Martin Ryhl; Haglind, Fredrik

2015-01-01

Highlights: • Detailed algorithm to solve high temperature Kalina cycle in part load. • A central receiver concentrating solar power plant with direct vapour generation considered as case study. • Part-load performance curves and fitted equations presented. - Abstract: The Kalina cycle has recently seen increased interest as an alternative to the conventional steam Rankine cycle. The cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine bottoming cycle, and solar power plants. The high temperature cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels, and several heat exchangers. This paper presents a detailed approach to solve the Kalina cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500 °C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated by changing the solar heat input to the receiver. Compared with the steam Rankine cycle, the Kalina cycle has an additional degree of freedom in terms of the ammonia mass fraction which can be varied in order to maximize the part-load efficiency of the cycle. The results include the part-load curves for various turbine inlet ammonia mass fractions and the fitted equations for these curves.

Utility Maximization in Nonconvex Wireless Systems

CERN Document Server

Brehmer, Johannes

2012-01-01

This monograph formulates a framework for modeling and solving utility maximization problems in nonconvex wireless systems. First, a model for utility optimization in wireless systems is defined. The model is general enough to encompass a wide array of system configurations and performance objectives. Based on the general model, a set of methods for solving utility maximization problems is developed. The development is based on a careful examination of the properties that are required for the application of each method. The focus is on problems whose initial formulation does not allow for a solution by standard convex methods. Solution approaches that take into account the nonconvexities inherent to wireless systems are discussed in detail. The monograph concludes with two case studies that demonstrate the application of the proposed framework to utility maximization in multi-antenna broadcast channels.

The use of gas based energy conversion cycles for sodium fast reactors

International Nuclear Information System (INIS)

Saez, M.; Haubensack, D.; Alpy, N.; Gerber, A.; Daid, F.

2008-01-01

In the frame of Sodium Fast Reactors, CEA, AREVA and EDF are involved in a substantial effort providing both significant expertise and original work in order to investigate the interest to use a gas based energy conversion cycle as an alternative to the classical steam cycle. These gas cycles consist in different versions of the Brayton cycle, various types of gas being considered (helium, nitrogen, argon, separately or mixed, sub or supercritical carbon dioxide) as well as various cycle arrangements (indirect, indirect / combined cycles). The interest of such cycles is analysed in details by thermodynamic calculations and cycle optimisations. The objective of this paper is to provide a comparison between gas based energy conversion cycles from the viewpoint of the overall plant efficiency. Key factors affecting the Brayton cycle efficiency include the turbine inlet temperature, compressors and turbine efficiencies, recuperator effectiveness and cycle pressure losses. A nitrogen Brayton cycle at high pressure (between 100 and 180 bar) could appear as a potential near-term solution of classical gas power conversion system for maximizing the plant efficiency. At long-term, supercritical carbon dioxide Brayton cycle appears very promising for Sodium Fast Reactors, with a potential of high efficiency using even at a core outlet temperature of 545 deg. C. (authors)

The Impact of Menstrual Cycle Phase on Economic Choice and Rationality.

Science.gov (United States)

Lazzaro, Stephanie C; Rutledge, Robb B; Burghart, Daniel R; Glimcher, Paul W

2016-01-01

It is well known that hormones affect both brain and behavior, but less is known about the extent to which hormones affect economic decision-making. Numerous studies demonstrate gender differences in attitudes to risk and loss in financial decision-making, often finding that women are more loss and risk averse than men. It is unclear what drives these effects and whether cyclically varying hormonal differences between men and women contribute to differences in economic preferences. We focus here on how economic rationality and preferences change as a function of menstrual cycle phase in women. We tested adherence to the Generalized Axiom of Revealed Preference (GARP), the standard test of economic rationality. If choices satisfy GARP then there exists a well-behaved utility function that the subject's decisions maximize. We also examined whether risk attitudes and loss aversion change as a function of cycle phase. We found that, despite large fluctuations in hormone levels, women are as technically rational in their choice behavior as their male counterparts at all phases of the menstrual cycle. However, women are more likely to choose risky options that can lead to potential losses while ovulating; during ovulation women are less loss averse than men and therefore more economically rational than men in this regard. These findings may have market-level implications: ovulating women more effectively maximize expected value than do other groups.

The Impact of Menstrual Cycle Phase on Economic Choice and Rationality.

Directory of Open Access Journals (Sweden)

Stephanie C Lazzaro

Full Text Available It is well known that hormones affect both brain and behavior, but less is known about the extent to which hormones affect economic decision-making. Numerous studies demonstrate gender differences in attitudes to risk and loss in financial decision-making, often finding that women are more loss and risk averse than men. It is unclear what drives these effects and whether cyclically varying hormonal differences between men and women contribute to differences in economic preferences. We focus here on how economic rationality and preferences change as a function of menstrual cycle phase in women. We tested adherence to the Generalized Axiom of Revealed Preference (GARP, the standard test of economic rationality. If choices satisfy GARP then there exists a well-behaved utility function that the subject's decisions maximize. We also examined whether risk attitudes and loss aversion change as a function of cycle phase. We found that, despite large fluctuations in hormone levels, women are as technically rational in their choice behavior as their male counterparts at all phases of the menstrual cycle. However, women are more likely to choose risky options that can lead to potential losses while ovulating; during ovulation women are less loss averse than men and therefore more economically rational than men in this regard. These findings may have market-level implications: ovulating women more effectively maximize expected value than do other groups.

Performance assessment and optimization of an irreversible nano-scale Stirling engine cycle operating with Maxwell-Boltzmann gas

Science.gov (United States)

Ahmadi, Mohammad H.; Ahmadi, Mohammad-Ali; Pourfayaz, Fathollah

2015-09-01

Developing new technologies like nano-technology improves the performance of the energy industries. Consequently, emerging new groups of thermal cycles in nano-scale can revolutionize the energy systems' future. This paper presents a thermo-dynamical study of a nano-scale irreversible Stirling engine cycle with the aim of optimizing the performance of the Stirling engine cycle. In the Stirling engine cycle the working fluid is an Ideal Maxwell-Boltzmann gas. Moreover, two different strategies are proposed for a multi-objective optimization issue, and the outcomes of each strategy are evaluated separately. The first strategy is proposed to maximize the ecological coefficient of performance (ECOP), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F . Furthermore, the second strategy is suggested to maximize the thermal efficiency ( η), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F). All the strategies in the present work are executed via a multi-objective evolutionary algorithms based on NSGA∥ method. Finally, to achieve the final answer in each strategy, three well-known decision makers are executed. Lastly, deviations of the outcomes gained in each strategy and each decision maker are evaluated separately.

Effects of Estrogen Fluctuation during the Menstrual Cycle on the Response to Stretch-Shortening Exercise in Females

Directory of Open Access Journals (Sweden)

Saulė Sipavičienė

2013-01-01

Full Text Available The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n=18; age = 20.2 ± 1.7 yr participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72 h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue between the two menstrual cycle phases were small.

Multi-objective optimization and exergetic-sustainability of an irreversible nano scale Braysson cycle operating with Ma

Directory of Open Access Journals (Sweden)

Mohammad H. Ahmadi

2016-06-01

Full Text Available Nano technology is developed in this decade and changes the way of life. Moreover, developing nano technology has effect on the performance of the materials and consequently improves the efficiency and robustness of them. So, nano scale thermal cycles will be probably engaged in the near future. In this paper, a nano scale irreversible Braysson cycle is studied thermodynamically for optimizing the performance of the Braysson cycle. In the aforementioned cycle an ideal Maxwell–Boltzmann gas is used as a working fluid. Furthermore, three different plans are used for optimizing with multi-objectives; though, the outputs of the abovementioned plans are assessed autonomously. Throughout the first plan, with the purpose of maximizing the ecological coefficient of performance and energy efficiency of the system, multi-objective optimization algorithms are used. Furthermore, in the second plan, two objective functions containing the ecological coefficient of performance and the dimensionless Maximum available work are maximized synchronously by utilizing multi-objective optimization approach. Finally, throughout the third plan, three objective functions involving the dimensionless Maximum available work, the ecological coefficient of performance and energy efficiency of the system are maximized synchronously by utilizing multi-objective optimization approach. The multi-objective evolutionary approach based on the non-dominated sorting genetic algorithm approach is used in this research. Making a decision is performed by three different decision makers comprising linear programming approaches for multidimensional analysis of preference and an approach for order of preference by comparison with ideal answer and Bellman–Zadeh. Lastly, analysis of error is employed to determine deviation of the outcomes gained from each plan.

From Cycling Between Coupled Reactions to the Cross-Bridge Cycle: Mechanical Power Output as an Integral Part of Energy Metabolism

Directory of Open Access Journals (Sweden)

Frank Diederichs

2012-10-01

Full Text Available ATP delivery and its usage are achieved by cycling of respective intermediates through interconnected coupled reactions. At steady state, cycling between coupled reactions always occurs at zero resistance of the whole cycle without dissipation of free energy. The cross-bridge cycle can also be described by a system of coupled reactions: one energising reaction, which energises myosin heads by coupled ATP splitting, and one de-energising reaction, which transduces free energy from myosin heads to coupled actin movement. The whole cycle of myosin heads via cross-bridge formation and dissociation proceeds at zero resistance. Dissipation of free energy from coupled reactions occurs whenever the input potential overcomes the counteracting output potential. In addition, dissipation is produced by uncoupling. This is brought about by a load dependent shortening of the cross-bridge stroke to zero, which allows isometric force generation without mechanical power output. The occurrence of maximal efficiency is caused by uncoupling. Under coupled conditions, Hill’s equation (velocity as a function of load is fulfilled. In addition, force and shortening velocity both depend on [Ca2+]. Muscular fatigue is triggered when ATP consumption overcomes ATP delivery. As a result, the substrate of the cycle, [MgATP2−], is reduced. This leads to a switch off of cycling and ATP consumption, so that a recovery of [ATP] is possible. In this way a potentially harmful, persistent low energy state of the cell can be avoided.

Juglans mandshurica Maxim extracts exhibit antitumor activity on HeLa cells in vitro.

Science.gov (United States)

Xin, Nian; Hasan, Murtaza; Li, Wei; Li, Yan

2014-04-01

The present study examined the potential application of Juglans mandshurica Maxim extracts (HT) for cancer therapy by assessing their anti‑proliferative activity, reduction of telomerase activity, induction of apoptosis and cell cycle arrest in S phase in HeLa cells. From the perspective of using HT as a herbal medicine, photomicroscopy and florescent microscopy techniques were utilized to characterize the effect of the extracts on telomerase activity and cell morphology. Flow cytometry was employed to study apoptosis and cell cycle of HeLa cells, and DNA laddering was performed. The results showed that HT inhibited cell proliferation and telomerase activity, induced apoptosis and caused S phase arrest of HeLa cells in vitro. HT inhibited HeLa cell proliferation significantly, and the highest inhibition rate was 83.7%. A trap‑silver staining assay showed that HT was capable of markedly decreasing telomerase activity of HeLa cells and this inhibition was enhanced in a time‑ and dose‑dependent manner. Results of a Hoechst 33258 staining assay showed that HeLa cells treated by HT induced cell death. Through DNA agarose gel electrophoresis, DNA ladders of HeLa cells treated with HT were observed, indicating apoptosis. In conclusion, the present study demonstrated that HT exhibited anti‑tumor effects comprising the inhibition of growth and telomerase activity as well as apoptosis and cell cycle arrest in HeLa cells.

Aging and loss decision making: increased risk aversion and decreased use of maximizing information, with correlated rationality and value maximization.

Science.gov (United States)

Kurnianingsih, Yoanna A; Sim, Sam K Y; Chee, Michael W L; Mullette-Gillman, O'Dhaniel A

2015-01-01

We investigated how adult aging specifically alters economic decision-making, focusing on examining alterations in uncertainty preferences (willingness to gamble) and choice strategies (what gamble information influences choices) within both the gains and losses domains. Within each domain, participants chose between certain monetary outcomes and gambles with uncertain outcomes. We examined preferences by quantifying how uncertainty modulates choice behavior as if altering the subjective valuation of gambles. We explored age-related preferences for two types of uncertainty, risk, and ambiguity. Additionally, we explored how aging may alter what information participants utilize to make their choices by comparing the relative utilization of maximizing and satisficing information types through a choice strategy metric. Maximizing information was the ratio of the expected value of the two options, while satisficing information was the probability of winning. We found age-related alterations of economic preferences within the losses domain, but no alterations within the gains domain. Older adults (OA; 61-80 years old) were significantly more uncertainty averse for both risky and ambiguous choices. OA also exhibited choice strategies with decreased use of maximizing information. Within OA, we found a significant correlation between risk preferences and choice strategy. This linkage between preferences and strategy appears to derive from a convergence to risk neutrality driven by greater use of the effortful maximizing strategy. As utility maximization and value maximization intersect at risk neutrality, this result suggests that OA are exhibiting a relationship between enhanced rationality and enhanced value maximization. While there was variability in economic decision-making measures within OA, these individual differences were unrelated to variability within examined measures of cognitive ability. Our results demonstrate that aging alters economic decision-making for

Aging and loss decision making: increased risk aversion and decreased use of maximizing information, with correlated rationality and value maximization

Directory of Open Access Journals (Sweden)

Yoanna Arlina Kurnianingsih

2015-05-01

Full Text Available We investigated how adult aging specifically alters economic decision-making, focusing on examining alterations in uncertainty preferences (willingness to gamble and choice strategies (what gamble information influences choices within both the gains and losses domains. Within each domain, participants chose between certain monetary outcomes and gambles with uncertain outcomes. We examined preferences by quantifying how uncertainty modulates choice behavior as if altering the subjective valuation of gambles. We explored age-related preferences for two types of uncertainty, risk and ambiguity. Additionally, we explored how aging may alter what information participants utilize to make their choices by comparing the relative utilization of maximizing and satisficing information types through a choice strategy metric. Maximizing information was the ratio of the expected value of the two options, while satisficing information was the probability of winning.We found age-related alterations of economic preferences within the losses domain, but no alterations within the gains domain. Older adults (OA; 61 to 80 years old were significantly more uncertainty averse for both risky and ambiguous choices. OA also exhibited choice strategies with decreased use of maximizing information. Within OA, we found a significant correlation between risk preferences and choice strategy. This linkage between preferences and strategy appears to derive from a convergence to risk neutrality driven by greater use of the effortful maximizing strategy. As utility maximization and value maximization intersect at risk neutrality, this result suggests that OA are exhibiting a relationship between enhanced rationality and enhanced value maximization. While there was variability in economic decision-making measures within OA, these individual differences were unrelated to variability within examined measures of cognitive ability. Our results demonstrate that aging alters economic

Simulated Partners and Collaborative Exercise (SPACE to boost motivation for astronauts: study protocol

Directory of Open Access Journals (Sweden)

Deborah L. Feltz

2016-11-01

Full Text Available Abstract Background Astronauts may have difficulty adhering to exercise regimens at vigorous intensity levels during long space missions. Vigorous exercise is important for aerobic and musculoskeletal health during space missions and afterwards. A key impediment to maintaining vigorous exercise is motivation. Finding ways to motivate astronauts to exercise at levels necessary to mitigate reductions in musculoskeletal health and aerobic capacity have not been explored. The focus of Simulated Partners and Collaborative Exercise (SPACE is to use recently documented motivation gains in task groups to heighten the exercise experience for participants, similar in age and fitness to astronauts, for vigorous exercise over a 6-month exercise regimen. A secondary focus is to determine the most effective features in simulated exercise partners for enhancing enjoyment, self-efficacy, and social connectedness. The aims of the project are to (1 Create software-generated (SG exercise partners and interface software with a cycle ergometer; (2 Pilot test design features of SG partners within a video exercise game (exergame, and (3 Test whether exercising with an SG partner over 24-week time period, compared to exercising alone, leads to greater work effort, aerobic capacity, muscle strength, exercise adherence, and enhanced psychological parameters. Methods/Design This study was approved by the Institutional Review Board (IRB. Chronic exercisers, between the ages 30 and 62, were asked to exercise on a cycle ergometer 6 days per week for 24 weeks using a routine consisting of alternating between moderate-intensity continuous and high-intensity interval sessions. Participants were assigned to one of three conditions: no partner (control, always faster SG partner, or SG partner who was not always faster. Participants were told they could vary cycle ergometer output to increase or decrease intensity during the sessions. Mean change in cycle ergometer power (watts

Life cycle - a wide vision of the control valves maintenance; Life cycle - uma visao ampla de manutencao de valvulas de controle

Energy Technology Data Exchange (ETDEWEB)

Souza, Jorge Marcos de [Metso Automation do Brasil, ES (Brazil)

2005-07-01

Nowadays the industry search more and more contracts which involve the total responsibility by the maintenance of its equipment. What could not be different for the control valves because of its importance and critic to the process. Because of this, the maintenance concept Life Cycle targets to involve all the phases of the life of each control valve, since the project until the day to day maintenance activities, maximizing the performance and generating benefits to the process. (author)

Peak oxygen uptake in a sprint interval testing protocol vs. maximal oxygen uptake in an incremental testing protocol and their relationship with cross-country mountain biking performance.

Science.gov (United States)

Hebisz, Rafał; Hebisz, Paulina; Zatoń, Marek; Michalik, Kamil

2017-04-01

In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak oxygen uptake (V̇O 2peak ) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to maximal oxygen uptake (V̇O 2max ) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased oxygen uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, oxygen uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak oxygen uptake in a sprint interval testing protocol than maximal oxygen uptake attained in an incremental testing protocol demonstrate superior competitive performance.

Maximally Informative Observables and Categorical Perception

OpenAIRE

Tsiang, Elaine

2012-01-01

We formulate the problem of perception in the framework of information theory, and prove that categorical perception is equivalent to the existence of an observable that has the maximum possible information on the target of perception. We call such an observable maximally informative. Regardless whether categorical perception is real, maximally informative observables can form the basis of a theory of perception. We conclude with the implications of such a theory for the problem of speech per...

Cardiovascular Response to Recreational Hockey in Middle-Aged Men.

Science.gov (United States)

Goodman, Zack A; Thomas, Scott G; Wald, Robert C; Goodman, Jack M

2017-06-15

The present study examined the hemodynamic response to recreational pick-up hockey relative to maximal exercise testing in middle-aged men. A total of 23 men with a mean age of 53 ± 7 years were studied. Graded exercise testing on a cycle ergometer determined maximal oxygen consumption, blood pressure (BP), and heart rate (HR). Ambulatory BP and Holter electrocardiographic monitoring was performed during one of their weekly hockey games (mean duration = 45 ± 7.2 minutes): for "On-Ice" responses (PLAY; data recorded while standing immediately after a shift; 8.0 ± 1.4 shifts per game) and during seated recovery (BENCH), 15 minutes after the game. On-Ice HRs and BPs were significantly higher than values obtained during maximal cycle exercise, respectively (HR 174 ± 8.9 vs 163 ± 11.0 beats/min) (systolic blood pressure 202 ± 20 vs 173 ± 31 mm Hg; p game, whereas HR increased from 139 ± 20 to 155 ± 16 beats/min during the game. The myocardial oxygen demand (myocardial time tension index) increased significantly during PLAY concurrent with a decrease in estimated myocardial oxygen supply (diastolic pressure time index), with the endocardial viability ratio during PLAY demonstrating a significant decrease during the third quarter of the game (1.25 ± 0.24) versus the first quarter (1.56 ± 0.30), which remained depressed 15 minutes post-game (p men is an extremely vigorous interval exercise with increasing relative intensity as the game progresses. Hockey elicits peak BPs and HRs that can exceed values observed during maximal exercise testing and is characterized by progressive increases in myocardial oxygen demand and lowered supply during PLAY and BENCH time. Given the progressive and high cardiovascular demands, caution is warranted when estimating the cardiovascular demands of hockey from clinical stress testing, particularly in those whom coronary reserve may be compromised. Copyright © 2017 Elsevier Inc. All rights reserved.

Respiratory ammonia output and blood ammonia concentration during incremental exercise

NARCIS (Netherlands)

Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ

The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

"Living high - training low" vs. "living high - training high": erythropoietic responses and performance of adolescent cross-country skiers.

Science.gov (United States)

Christoulas, K; Karamouzis, M; Mandroukas, K

2011-03-01

To determine and compare the erythropoietic response and exercise performance of adolescent cross-country skiers, as a result of "living high-training high" (HH) and "living high-training low" (HL). Nine female and six male adolescent cross-country skiers volunteered to participate in separate trials. In the first trial (HH), the skiers lived and trained for 21 days at 1550-2050 m, while in the second trial (HL) they trained near sea level (450-500 m) but resided at 1550 m. All participants underwent maximal cycle ergometer tests for the determination of VO2max and cardiorespiratory parameters via an open circuit system at sea level before ascent to altitude, and 1-2 days after descent from altitude. Blood samples were drawn prior to and immediately after maximal cycle exercise testing, at sea level prior to ascent, on days 1 (D1) and 21 (D21) at altitude (1740 m), and 1-2 days post-altitude, for the determination of serum erythropoietin (EPO) concentration, haemoglobin (Hb), hematocrit (Ht), and red blood cell (RBC) volume. The results showed that both boys and girls cross-country skiers, significantly improved their sea level VO2max after 21 days of living at moderate altitude and training near sea level. The present study demonstrates that living at moderate altitude, 1550-2050 m and training low, near sea level (450-500 m) significantly increases VO2max and RBC mass for both boys and girls. Results indicate that applying the training concept "living high - training low" in adolescent athletes may improve their endurance performance.

Maximally Entangled Multipartite States: A Brief Survey

International Nuclear Information System (INIS)

Enríquez, M; Wintrowicz, I; Życzkowski, K

2016-01-01

The problem of identifying maximally entangled quantum states of a composite quantum systems is analyzed. We review some states of multipartite systems distinguished with respect to certain measures of quantum entanglement. Numerical results obtained for 4-qubit pure states illustrate the fact that the notion of maximally entangled state depends on the measure used. (paper)

Corporate Social Responsibility and Profit Maximizing Behaviour

OpenAIRE

Becchetti, Leonardo; Giallonardo, Luisa; Tessitore, Maria Elisabetta

2005-01-01

We examine the behavior of a profit maximizing monopolist in a horizontal differentiation model in which consumers differ in their degree of social responsibility (SR) and consumers SR is dynamically influenced by habit persistence. The model outlines parametric conditions under which (consumer driven) corporate social responsibility is an optimal choice compatible with profit maximizing behavior.

Simulation and parametric optimisation of thermal power plant cycles

Directory of Open Access Journals (Sweden)

P. Ravindra Kumar

2016-09-01

Full Text Available The objective of the paper is to analyse parametric studies and optimum steam extraction pressures of three different (subcritical, supercritical and ultra-supercritical coal fired power plant cycles at a particular main steam temperature of 600 °C by keeping the reheat temperature at 537 °C and condenser pressure at 0.09 bar as constant. In order to maximize the heat rate gain possible with supercritical and ultra-supercritical steam conditions, eight stages of feed water heater arrangement with single reheater is considered. The system is optimized in such a way that the percentage exergetic losses are reduced for the increase of the exergetic efficiency and higher fuel utilization. The plant cycles are simulated and optimized by using Cycle Tempo 5.0 simulation software tool. From the simulation study, it is observed that the thermal efficiency of the three different power plant cycles obtained as 41.40, 42.48 and 43.03%, respectively. The specific coal consumption for three different power plant cycles are 0.56, 0.55 and 0.54 Tonnes/MWh. The improvement in feed water temperatures at the inlet of steam generator of respective cycles are 291, 305 and 316 °C.

Leg joint power output during progressive resistance FES-LCE cycling in SCI subjects: developing an index of fatigue

Directory of Open Access Journals (Sweden)

Faghri Pouran D

2008-04-01

Full Text Available Abstract Background The purpose of this study was to investigate the biomechanics of the hip, knee and ankle during a progressive resistance cycling protocol in an effort to detect and measure the presence of muscle fatigue. It was hypothesized that knee power output can be used as an indicator of fatigue in order to assess the cycling performance of SCI subjects. Methods Six spinal cord injured subjects (2 incomplete, 4 complete between the ages of twenty and fifty years old and possessing either a complete or incomplete spinal cord injury at or below the fourth cervical vertebra participated in this study. Kinematic data and pedal forces were recorded during cycling at increasing levels of resistance. Ankle, knee and hip power outputs and resultant pedal force were calculated. Ergometer cadence and muscle stimulation intensity were also recorded. Results The main findings of this study were: (a ankle and knee power outputs decreased, whereas hip power output increased with increasing resistance, (b cadence, stimulation intensity and resultant pedal force in that combined order were significant predictors of knee power output and (c knowing the value of these combined predictors at 10 rpm, an index of fatigue can be developed, quantitatively expressing the power capacity of the knee joint with respect to a baseline power level defined as fatigue. Conclusion An index of fatigue was successfully developed, proportionalizing knee power capacity during cycling to a predetermined value of fatigue. The fatigue index value at 0/8th kp, measured 90 seconds into active, unassisted pedaling was 1.6. This indicates initial power capacity at the knee to be 1.6 times greater than fatigue. The fatigue index decreased to 1.1 at 2/8th kp, representing approximately a 30% decrease in the knee's power capacity within a 4 minute timespan. These findings suggest that the present cycling protocol is not sufficient for a rider to gain the benefits of FES and thus

Leg joint power output during progressive resistance FES-LCE cycling in SCI subjects: developing an index of fatigue.

Science.gov (United States)

Haapala, Stephenie A; Faghri, Pouran D; Adams, Douglas J

2008-04-26

The purpose of this study was to investigate the biomechanics of the hip, knee and ankle during a progressive resistance cycling protocol in an effort to detect and measure the presence of muscle fatigue. It was hypothesized that knee power output can be used as an indicator of fatigue in order to assess the cycling performance of SCI subjects. Six spinal cord injured subjects (2 incomplete, 4 complete) between the ages of twenty and fifty years old and possessing either a complete or incomplete spinal cord injury at or below the fourth cervical vertebra participated in this study. Kinematic data and pedal forces were recorded during cycling at increasing levels of resistance. Ankle, knee and hip power outputs and resultant pedal force were calculated. Ergometer cadence and muscle stimulation intensity were also recorded. The main findings of this study were: (a) ankle and knee power outputs decreased, whereas hip power output increased with increasing resistance, (b) cadence, stimulation intensity and resultant pedal force in that combined order were significant predictors of knee power output and (c) knowing the value of these combined predictors at 10 rpm, an index of fatigue can be developed, quantitatively expressing the power capacity of the knee joint with respect to a baseline power level defined as fatigue. An index of fatigue was successfully developed, proportionalizing knee power capacity during cycling to a predetermined value of fatigue. The fatigue index value at 0/8th kp, measured 90 seconds into active, unassisted pedaling was 1.6. This indicates initial power capacity at the knee to be 1.6 times greater than fatigue. The fatigue index decreased to 1.1 at 2/8th kp, representing approximately a 30% decrease in the knee's power capacity within a 4 minute timespan. These findings suggest that the present cycling protocol is not sufficient for a rider to gain the benefits of FES and thus raises speculation as to whether or not progressive resistance

Guinea pig maximization test

DEFF Research Database (Denmark)

Andersen, Klaus Ejner

1985-01-01

Guinea pig maximization tests (GPMT) with chlorocresol were performed to ascertain whether the sensitization rate was affected by minor changes in the Freund's complete adjuvant (FCA) emulsion used. Three types of emulsion were evaluated: the oil phase was mixed with propylene glycol, saline...

Effects of posture on upper and lower limb peripheral resistance following submaximal cycling.

Science.gov (United States)

Swan, P D; Spitler, D L; Todd, M K; Maupin, J L; Lewis, C L; Darragh, P M

1989-09-01

The purpose of this study was to determine postural effects on upper and lower limb peripheral resistance (PR) after submaximal exercise. Twelve subjects (six men and six women) completed submaximal cycle ergometer tests (60% age-predicted maximum heart rate) in the supine and upright seated positions. Each test included 20 minutes of rest, 20 minutes of cycling, and 15 minutes of recovery. Stroke volume and heart rate were determined by impedance cardiography, and blood pressure was measured by auscultation during rest, immediately after exercise, and at minutes 1-5, 7.5, 10, 12.5, and 15 of recovery. Peripheral resistance was calculated from values of mean arterial pressure and cardiac output. No significant (p less than 0.05) postural differences in PR were noted during rest for either limb. Immediately after exercise, PR decreased (55% to 61%) from resting levels in both limbs, independent of posture. Recovery ankle PR values were significantly different between postures. Upright ankle PR returned to 92% of the resting level within four minutes of recovery, compared to 76% of the resting level after 15 minutes in the supine posture. Peripheral resistance values in the supine and upright arm were not affected by posture and demonstrated a gradual pattern of recovery similar to the supine ankle recovery response (85% to 88% of rest within 15 minutes). The accelerated recovery rate of PR after upright exercise may result from local vasoconstriction mediated by a central regulatory response to stimulation from gravitational pressure on lower body circulation.

Gradient Dynamics and Entropy Production Maximization

Science.gov (United States)

Janečka, Adam; Pavelka, Michal

2018-01-01

We compare two methods for modeling dissipative processes, namely gradient dynamics and entropy production maximization. Both methods require similar physical inputs-how energy (or entropy) is stored and how it is dissipated. Gradient dynamics describes irreversible evolution by means of dissipation potential and entropy, it automatically satisfies Onsager reciprocal relations as well as their nonlinear generalization (Maxwell-Onsager relations), and it has statistical interpretation. Entropy production maximization is based on knowledge of free energy (or another thermodynamic potential) and entropy production. It also leads to the linear Onsager reciprocal relations and it has proven successful in thermodynamics of complex materials. Both methods are thermodynamically sound as they ensure approach to equilibrium, and we compare them and discuss their advantages and shortcomings. In particular, conditions under which the two approaches coincide and are capable of providing the same constitutive relations are identified. Besides, a commonly used but not often mentioned step in the entropy production maximization is pinpointed and the condition of incompressibility is incorporated into gradient dynamics.

Application of Pharmacokinetics and Pharmacodynamics in Product Life Cycle Management. A Case Study with a Carbidopa-Levodopa Extended-Release Formulation.

Science.gov (United States)

Modi, Nishit B

2017-05-01

Increasing costs in discovering and developing new molecular entities and the continuing debate on limited company pipelines mean that pharmaceutical companies are under significant pressure to maximize the value of approved products. Life cycle management in the context of drug development comprises activities to maximize the effective life of a product. Life cycle approaches can involve new formulations, new routes of delivery, new indications or expansion of the population for whom the product is indicated, or development of combination products. Life cycle management may provide an opportunity to improve upon the current product through enhanced efficacy or reduced side effects and could expand the therapeutic market for the product. Successful life cycle management may include the potential for superior efficacy, improved tolerability, or a better prescriber or patient acceptance. Unlike generic products where bioequivalence to an innovator product may be sufficient for drug approval, life cycle management typically requires a series of studies to characterize the value of the product. This review summarizes key considerations in identifying product candidates that may be suitable for life cycle management and discusses the application of pharmacokinetics and pharmacodynamics in developing new products using a life cycle management approach. Examples and a case study to illustrate how pharmacokinetics and pharmacodynamics contributed to the selection of dosing regimens, demonstration of an improved therapeutic effect, or regulatory approval of an improved product label are presented.

On Maximal Non-Disjoint Families of Subsets

Directory of Open Access Journals (Sweden)

Yu. A. Zuev

2017-01-01

Full Text Available The paper studies maximal non-disjoint families of subsets of a finite set. Non-disjointness means that any two subsets of a family have a nonempty intersection. The maximality is expressed by the fact that adding a new subset to the family cannot increase its power without violating a non-disjointness condition. Studying the properties of such families is an important section of the extreme theory of sets. Along with purely combinatorial interest, the problems considered here play an important role in informatics, anti-noise coding, and cryptography.In 1961 this problem saw the light of day in the Erdos, Ko and Rado paper, which established a maximum power of the non-disjoint family of subsets of equal power. In 1974 the Erdos and Claytman publication estimated the number of maximal non-disjoint families of subsets without involving the equality of their power. These authors failed to establish an asymptotics of the logarithm of the number of such families when the power of a basic finite set tends to infinity. However, they suggested such an asymptotics as a hypothesis. A.D. Korshunov in two publications in 2003 and 2005 established the asymptotics for the number of non-disjoint families of the subsets of arbitrary powers without maximality condition of these families.The basis for the approach used in the paper to study the families of subsets is their description in the language of Boolean functions. A one-to-one correspondence between a family of subsets and a Boolean function is established by the fact that the characteristic vectors of subsets of a family are considered to be the unit sets of a Boolean function. The main theoretical result of the paper is that the maximal non-disjoint families are in one-to-one correspondence with the monotonic self-dual Boolean functions. When estimating the number of maximal non-disjoint families, this allowed us to use the result of A.A. Sapozhenko, who established the asymptotics of the number of the

Inquiry in bibliography some of the bustan`s maxim

Directory of Open Access Journals (Sweden)

sajjad rahmatian

2016-12-01

Full Text Available Sa`di is on of those poets who`s has placed a special position to preaching and guiding the people and among his works, allocated throughout the text of bustan to advice and maxim on legal and ethical various subjects. Surely, sa`di on the way of to compose this work and expression of its moral point, direct or indirect have been affected by some previous sources and possibly using their content. The main purpose of this article is that the pay review of basis and sources of bustan`s maxims and show that sa`di when expression the maxims of this work has been affected by which of the texts and works. For this purpose is tried to with search and research on the resources that have been allocated more or less to the aphorisms, to discover and extract traces of influence sa`di from their moral and didactic content. From the most important the finding of this study can be mentioned that indirect effect of some pahlavi books of maxim (like maxims of azarbad marespandan and bozorgmehr book of maxim and also noted sa`di directly influenced of moral and ethical works of poets and writers before him, and of this, sa`di`s influence from abo- shakur balkhi maxims, ferdowsi and keikavus is remarkable and noteworthy.

Can monkeys make investments based on maximized pay-off?

Directory of Open Access Journals (Sweden)

Sophie Steelandt

2011-03-01

Full Text Available Animals can maximize benefits but it is not known if they adjust their investment according to expected pay-offs. We investigated whether monkeys can use different investment strategies in an exchange task. We tested eight capuchin monkeys (Cebus apella and thirteen macaques (Macaca fascicularis, Macaca tonkeana in an experiment where they could adapt their investment to the food amounts proposed by two different experimenters. One, the doubling partner, returned a reward that was twice the amount given by the subject, whereas the other, the fixed partner, always returned a constant amount regardless of the amount given. To maximize pay-offs, subjects should invest a maximal amount with the first partner and a minimal amount with the second. When tested with the fixed partner only, one third of monkeys learned to remove a maximal amount of food for immediate consumption before investing a minimal one. With both partners, most subjects failed to maximize pay-offs by using different decision rules with each partner' quality. A single Tonkean macaque succeeded in investing a maximal amount to one experimenter and a minimal amount to the other. The fact that only one of over 21 subjects learned to maximize benefits in adapting investment according to experimenters' quality indicates that such a task is difficult for monkeys, albeit not impossible.

Maximal lattice free bodies, test sets and the Frobenius problem

DEFF Research Database (Denmark)

Jensen, Anders Nedergaard; Lauritzen, Niels; Roune, Bjarke Hammersholt

Maximal lattice free bodies are maximal polytopes without interior integral points. Scarf initiated the study of maximal lattice free bodies relative to the facet normals in a fixed matrix. In this paper we give an efficient algorithm for computing the maximal lattice free bodies of an integral m...... method is inspired by the novel algorithm by Einstein, Lichtblau, Strzebonski and Wagon and the Groebner basis approach by Roune....

Nuclear cycle length economics strategy using stochastic and deterministic Monte Carlo computation models

International Nuclear Information System (INIS)

Wook Ahn, T.

2014-01-01

Nuclear power plants (NPP) have historically been a low cost base-load electricity source because of their high fuel density and operational reliability. In the United States, NPPs typically run 18- to 24-month cycles to limit outage times and maximize capacity factor. recently, however, increased volatility in energy and fuel prices, lower natural gas prices, higher material costs, and new sources are challenging the nuclear industry. This warrants a study in developing a more robust cycle length and fuel burnup strategy to make NPPs more competitive. (Author)

Nuclear cycle length economics strategy using stochastic and deterministic Monte Carlo computation models

Energy Technology Data Exchange (ETDEWEB)

Wook Ahn, T.

2014-07-01

Nuclear power plants (NPP) have historically been a low cost base-load electricity source because of their high fuel density and operational reliability. In the United States, NPPs typically run 18- to 24-month cycles to limit outage times and maximize capacity factor. recently, however, increased volatility in energy and fuel prices, lower natural gas prices, higher material costs, and new sources are challenging the nuclear industry. This warrants a study in developing a more robust cycle length and fuel burnup strategy to make NPPs more competitive. (Author)

Disk Density Tuning of a Maximal Random Packing.

Science.gov (United States)

Ebeida, Mohamed S; Rushdi, Ahmad A; Awad, Muhammad A; Mahmoud, Ahmed H; Yan, Dong-Ming; English, Shawn A; Owens, John D; Bajaj, Chandrajit L; Mitchell, Scott A

2016-08-01

We introduce an algorithmic framework for tuning the spatial density of disks in a maximal random packing, without changing the sizing function or radii of disks. Starting from any maximal random packing such as a Maximal Poisson-disk Sampling (MPS), we iteratively relocate, inject (add), or eject (remove) disks, using a set of three successively more-aggressive local operations. We may achieve a user-defined density, either more dense or more sparse, almost up to the theoretical structured limits. The tuned samples are conflict-free, retain coverage maximality, and, except in the extremes, retain the blue noise randomness properties of the input. We change the density of the packing one disk at a time, maintaining the minimum disk separation distance and the maximum domain coverage distance required of any maximal packing. These properties are local, and we can handle spatially-varying sizing functions. Using fewer points to satisfy a sizing function improves the efficiency of some applications. We apply the framework to improve the quality of meshes, removing non-obtuse angles; and to more accurately model fiber reinforced polymers for elastic and failure simulations.

An information maximization model of eye movements

Science.gov (United States)

Renninger, Laura Walker; Coughlan, James; Verghese, Preeti; Malik, Jitendra

2005-01-01

We propose a sequential information maximization model as a general strategy for programming eye movements. The model reconstructs high-resolution visual information from a sequence of fixations, taking into account the fall-off in resolution from the fovea to the periphery. From this framework we get a simple rule for predicting fixation sequences: after each fixation, fixate next at the location that minimizes uncertainty (maximizes information) about the stimulus. By comparing our model performance to human eye movement data and to predictions from a saliency and random model, we demonstrate that our model is best at predicting fixation locations. Modeling additional biological constraints will improve the prediction of fixation sequences. Our results suggest that information maximization is a useful principle for programming eye movements.

Frequency band analysis of muscle activation during cycling to exhaustion

Directory of Open Access Journals (Sweden)

Fernando Diefenthaeler

2012-04-01

Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p243 Lower limb muscles activation was assessed during cycling to exhaustion using frequency band analysis. Nine cyclists were evaluated in two days. On the first day, cyclists performed a maximal incremental cycling exercise to measure peak power output, which was used on the second day to define the workload for a constant load time to exhaustion cycling exercise (maximal aerobic power output from day 1. Muscle activation of vastus lateralis (VL, long head of biceps femoris (BF, lateral head of gastrocnemius (GL, and tibialis anterior (TA from the right lower limb was recorded during the time to exhaustion cycling exercise. A series of nine band-pass Butterworth digital filters was used to analyze muscle activity amplitude for each band. The overall amplitude of activation and the high and low frequency components were defined to assess the magnitude of fatigue effects on muscle activity via effect sizes. The profile of the overall muscle activation during the test was analyzed using a second order polynomial, and the variability of the overall bands was analyzed by the coefficient of variation for each muscle in each instant of the test. Substantial reduction in the high frequency components of VL and BF activation was observed. The overall and low frequency bands presented trivial to small changes for all muscles. High relationship between the second order polynomial fitting and muscle activity was found (R2 > 0.89 for all muscles. High variability (~25% was found for muscle activation at the four instants of the fatigue test. Changes in the spectral properties of the EMG signal were only substantial when extreme changes in fatigue state were induced.

After-effects of night work on physical performance capacity and sleep quality in relation to age

NARCIS (Netherlands)

de Zwart, B. C.; Bras, V. M.; van Dormolen, M.; Frings-Dresen, M. H.; Meijman, T. F.

1993-01-01

The after-effects of night work on physical performance capacity and sleep quality were studied. Ten younger (age < or = 34 years) and eight older (age > 34 years) experienced shift workers were examined. Subjects performed cycle ergometer tests at an exercise intensity requiring 70% of the

Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander

International Nuclear Information System (INIS)

Yang Junlan; Ma Yitai; Li Minxia; Guan Haiqing

2005-01-01

In this paper, a comparative study is performed for the transcritical carbon dioxide refrigeration cycles with a throttling valve and with an expander, based on the first and second laws of thermodynamics. The effects of evaporating temperature and outlet temperature of gas cooler on the optimal heat rejection pressure, the coefficients of performance (COP), the exergy losses, and the exergy efficiencies are investigated. In order to identify the amounts and locations of irreversibility within the two cycles, exergy analysis is employed to study the thermodynamics process in each component. It is found that in the throttling valve cycle, the largest exergy loss occurs in the throttling valve, about 38% of the total cycle irreversibility. In the expander cycle, the irreversibility mainly comes from the gas cooler and the compressor, approximately 38% and 35%, respectively. The COP and exergy efficiency of the expander cycle are on average 33% and 30% higher than those of the throttling valve cycle, respectively. It is also concluded that an optimal heat rejection pressure can be obtained for all the operating conditions to maximize the COP. The analysis results are of significance to provide theoretical basis for optimization design and operation control of the transcritical carbon dioxide cycle with an expander

An experimental and theoretical study on an injection-assisted air-conditioner using R32 in the refrigeration cycle

International Nuclear Information System (INIS)

Qv, Dehu; Dong, Bingbing; Cao, Lin; Ni, Long; Wang, Jijin; Shang, Runxin; Yao, Yang

2017-01-01

Highlights: • An advanced injection-assisted air-conditioner (IAC) using R32 was proposed. • In the whole day-night cycle, cooling capacity and energy efficiency ratio of the IAC were enhanced dramatically. • The injection duration of 8 s maximized the IAC cooling potential. • Two-phase injection attained the highest exergetic efficiency approximating 50% or more. • The economic and environmental benefits of the IAC were demonstrated. - Abstract: An air-conditioner (AC) that uses refrigerant R32 assisted with one-phase vapor injection shows high energy efficiency and low discharge temperature in the heat-pump cycle, but the performance is not satisfactory in the refrigeration cycle. In this study, an improved injection cycle consisting of one-phase vapor injection mode and two-phase injection mode is proposed and integrated into an AC using R32, which is now referred to as an advanced injection-assisted air-conditioner (IAC). Through an experimental and theoretical study, an optimal injection duration of 8 s is attained for maximizing the refrigeration potential of the IAC. Furthermore, in an entire day–night cycle, both the cooling capacity and energy efficiency ratio (EER) of the IAC within the two-phase injection cycle are enhanced by 25% and 32%, respectively, compared with those of a noninjection-assisted AC. Moreover, two-phase injection offers the highest exergetic efficiency, approximately 50% or more in the refrigeration cycle, exhibiting remarkable thermodynamic performance of the IAC. In addition, compared to the conventional AC using R410A, the IAC using R32 within a two-phase injection cycle demonstrates reasonable payback performance and substantial reduction in carbon dioxide and sulfur dioxide emissions in the refrigeration cycle.

On the way towards a generalized entropy maximization procedure

International Nuclear Information System (INIS)

Bagci, G. Baris; Tirnakli, Ugur

2009-01-01

We propose a generalized entropy maximization procedure, which takes into account the generalized averaging procedures and information gain definitions underlying the generalized entropies. This novel generalized procedure is then applied to Renyi and Tsallis entropies. The generalized entropy maximization procedure for Renyi entropies results in the exponential stationary distribution asymptotically for q element of (0,1] in contrast to the stationary distribution of the inverse power law obtained through the ordinary entropy maximization procedure. Another result of the generalized entropy maximization procedure is that one can naturally obtain all the possible stationary distributions associated with the Tsallis entropies by employing either ordinary or q-generalized Fourier transforms in the averaging procedure.

Violating Bell inequalities maximally for two d-dimensional systems

International Nuclear Information System (INIS)

Chen Jingling; Wu Chunfeng; Oh, C. H.; Kwek, L. C.; Ge Molin

2006-01-01

We show the maximal violation of Bell inequalities for two d-dimensional systems by using the method of the Bell operator. The maximal violation corresponds to the maximal eigenvalue of the Bell operator matrix. The eigenvectors corresponding to these eigenvalues are described by asymmetric entangled states. We estimate the maximum value of the eigenvalue for large dimension. A family of elegant entangled states |Ψ> app that violate Bell inequality more strongly than the maximally entangled state but are somewhat close to these eigenvectors is presented. These approximate states can potentially be useful for quantum cryptography as well as many other important fields of quantum information

Real-time topic-aware influence maximization using preprocessing.

Science.gov (United States)

Chen, Wei; Lin, Tian; Yang, Cheng

2016-01-01

Influence maximization is the task of finding a set of seed nodes in a social network such that the influence spread of these seed nodes based on certain influence diffusion model is maximized. Topic-aware influence diffusion models have been recently proposed to address the issue that influence between a pair of users are often topic-dependent and information, ideas, innovations etc. being propagated in networks are typically mixtures of topics. In this paper, we focus on the topic-aware influence maximization task. In particular, we study preprocessing methods to avoid redoing influence maximization for each mixture from scratch. We explore two preprocessing algorithms with theoretical justifications. Our empirical results on data obtained in a couple of existing studies demonstrate that one of our algorithms stands out as a strong candidate providing microsecond online response time and competitive influence spread, with reasonable preprocessing effort.

A Multi-Cycle Q-Modulation for Dynamic Optimization of Inductive Links.

Science.gov (United States)

Lee, Byunghun; Yeon, Pyungwoo; Ghovanloo, Maysam

2016-08-01

This paper presents a new method, called multi-cycle Q-modulation, which can be used in wireless power transmission (WPT) to modulate the quality factor (Q) of the receiver (Rx) coil and dynamically optimize the load impedance to maximize the power transfer efficiency (PTE) in two-coil links. A key advantage of the proposed method is that it can be easily implemented using off-the-shelf components without requiring fast switching at or above the carrier frequency, which is more suitable for integrated circuit design. Moreover, the proposed technique does not need any sophisticated synchronization between the power carrier and Q-modulation switching pulses. The multi-cycle Q-modulation is analyzed theoretically by a lumped circuit model, and verified in simulation and measurement using an off-the-shelf prototype. Automatic resonance tuning (ART) in the Rx, combined with multi-cycle Q-modulation helped maximizing PTE of the inductive link dynamically in the presence of environmental and loading variations, which can otherwise significantly degrade the PTE in multi-coil settings. In the prototype conventional 2-coil link, the proposed method increased the power amplifier (PA) plus inductive link efficiency from 4.8% to 16.5% at ( R L = 1 kΩ, d 23 = 3 cm), and from 23% to 28.2% at ( R L = 100 Ω, d 23 = 3 cm) after 11% change in the resonance capacitance, while delivering 168.1 mW to the load (PDL).

Personal customizing exercise with a wearable measurement and control unit.

Science.gov (United States)

Wang, Zhihui; Kiryu, Tohru; Tamura, Naoki

2005-06-28

Recently, wearable technology has been used in various health-related fields to develop advanced monitoring solutions. However, the monitoring function alone cannot meet all the requirements of customizing machine-based exercise on an individual basis by relying on biosignal-based controls. We propose a new wearable unit design equipped with measurement and control functions to support the customization process. The wearable unit can measure the heart rate and electromyogram signals during exercise performance and output workload control commands to the exercise machines. The workload is continuously tracked with exercise programs set according to personally customized workload patterns and estimation results from the measured biosignals by a fuzzy control method. Exercise programs are adapted by relying on a computer workstation, which communicates with the wearable unit via wireless connections. A prototype of the wearable unit was tested together with an Internet-based cycle ergometer system to demonstrate that it is possible to customize exercise on an individual basis. We tested the wearable unit in nine people to assess its suitability to control cycle ergometer exercise. The results confirmed that the unit could successfully control the ergometer workload and continuously support gradual changes in physical activities. The design of wearable units equipped with measurement and control functions is an important step towards establishing a convenient and continuously supported wellness environment.

Personal customizing exercise with a wearable measurement and control unit

Directory of Open Access Journals (Sweden)

Tamura Naoki

2005-06-01

Full Text Available Abstract Background Recently, wearable technology has been used in various health-related fields to develop advanced monitoring solutions. However, the monitoring function alone cannot meet all the requirements of customizing machine-based exercise on an individual basis by relying on biosignal-based controls. We propose a new wearable unit design equipped with measurement and control functions to support the customization process. Methods The wearable unit can measure the heart rate and electromyogram signals during exercise performance and output workload control commands to the exercise machines. The workload is continuously tracked with exercise programs set according to personally customized workload patterns and estimation results from the measured biosignals by a fuzzy control method. Exercise programs are adapted by relying on a computer workstation, which communicates with the wearable unit via wireless connections. A prototype of the wearable unit was tested together with an Internet-based cycle ergometer system to demonstrate that it is possible to customize exercise on an individual basis. Results We tested the wearable unit in nine people to assess its suitability to control cycle ergometer exercise. The results confirmed that the unit could successfully control the ergometer workload and continuously support gradual changes in physical activities. Conclusion The design of wearable units equipped with measurement and control functions is an important step towards establishing a convenient and continuously supported wellness environment.

El culto de Maximón en Guatemala

OpenAIRE

Pédron‑Colombani, Sylvie

2009-01-01

Este artículo se enfoca en la figura de Maximón, deidad sincrética de Guatemala, en un contexto de desplazamiento de la religión católica popular por parte de las iglesias protestantes. Esta divinidad híbrida a la cual se agregan santos católicos como Judas Iscariote o el dios maya Mam, permite la apropiación de Maximón por segmentos diferenciados de la población (tanto indígena como mestiza). Permite igualmente ser símbolo de protestas sociales enmascaradas cuando se asocia Maximón con figur...

Methodology of fuel cycles long-term safety assessment of SNF/HLW geological disposal

International Nuclear Information System (INIS)

Pritrsky, J.

2008-01-01

time varying parameter values; algebraic expressions to represent the uptake of contaminants by humans, other biota and additional output quantities of interest. This software has been used as well to calculate the total and relative radiotoxicity. The results showed that the advanced fuel cycles MOX and IMF are most perspective from the long-term safety point of view. Calculated maximal annual effective doses are as follows: 8.14x10 -9 Sv/year for the cycle UOX, 1.04x10 -9 Sv/year for the cycle MOX and 5.69x10 -1 0 Sv/year for the cycle IMF. Maximal annual effective dose occurs at time 6.13x10 3 years for all considered cycles. Most important contributors to the total dose are long-lived fission products in the period from 10 3 to 10 6 years ( 129 I, 14 C, 36 Cl, 79 Se, 99 Tc a 135 Cs). Later on, the decay series 4n+1 and 4n+2 become dominant, which is related to the slow movement of actinides due to sorption in the host rock. Performed sensitivity analysis showed that Darcy velocity of water movement and distance of the well are ranked among the most important input parameters that affect the values of maximal annual effective dose. Safety indicators have been calculated for amount of waste equivalent to production of 1 TWh e due to comparability of the outcomes. Presented doctoral thesis confirmed possibility to reduce significantly both the radiotoxicity and annual effective dose of advanced fuel cycles MOX and IMF in comparison with the conventional once-through UOX fuel cycle. Works performed and presented results have met expectations and can be finally used for the comparative assessment of the advanced nuclear fuel cycles based on the multi-criteria analysis approach. (Author)

Methodology of fuel cycles long-term safety assessment of SNF/HLW geological disposal

International Nuclear Information System (INIS)

Pritrsky, J.

2008-02-01

time varying parameter values; algebraic expressions to represent the uptake of contaminants by humans, other biota and additional output quantities of interest. This software has been used as well to calculate the total and relative radiotoxicity. The results showed that the advanced fuel cycles MOX and IMF are most perspective from the long-term safety point of view. Calculated maximal annual effective doses are as follows: 8.14x10 -9 Sv/year for the cycle UOX, 1.04x10 -9 Sv/year for the cycle MOX and 5.69x10 -1 0 Sv/year for the cycle IMF. Maximal annual effective dose occurs at time 6.13x10 3 years for all considered cycles. Most important contributors to the total dose are long-lived fission products in the period from 10 3 to 10 6 years ( 129 I, 14 C, 36 Cl, 79 Se, 99 Tc a 135 Cs). Later on, the decay series 4n+1 and 4n+2 become dominant, which is related to the slow movement of actinides due to sorption in the host rock. Performed sensitivity analysis showed that Darcy velocity of water movement and distance of the well are ranked among the most important input parameters that affect the values of maximal annual effective dose. Safety indicators have been calculated for amount of waste equivalent to production of 1 TWh e due to comparability of the outcomes. Presented doctoral thesis confirmed possibility to reduce significantly both the radiotoxicity and annual effective dose of advanced fuel cycles MOX and IMF in comparison with the conventional once-through UOX fuel cycle. Works performed and presented results have met expectations and can be finally used for the comparative assessment of the advanced nuclear fuel cycles based on the multi-criteria analysis approach. (Author)

Self-consistent collective-coordinate method for ''maximally-decoupled'' collective subspace and its boson mapping: Quantum theory of ''maximally-decoupled'' collective motion

International Nuclear Information System (INIS)

Marumori, T.; Sakata, F.; Maskawa, T.; Une, T.; Hashimoto, Y.

1983-01-01

The main purpose of this paper is to develop a full quantum theory, which is capable by itself of determining a ''maximally-decoupled'' collective motion. The paper is divided into two parts. In the first part, the motivation and basic idea of the theory are explained, and the ''maximal-decoupling condition'' on the collective motion is formulated within the framework of the time-dependent Hartree-Fock theory, in a general form called the invariance principle of the (time-dependent) Schrodinger equation. In the second part, it is shown that when the author positively utilize the invariance principle, we can construct a full quantum theory of the ''maximally-decoupled'' collective motion. This quantum theory is shown to be a generalization of the kinematical boson-mapping theories so far developed, in such a way that the dynamical ''maximal-decoupling condition'' on the collective motion is automatically satisfied

Evaluation of a combined cycle based on an HCCI (Homogenous Charge Compression Ignition) engine heat recovery employing two organic Rankine cycles

International Nuclear Information System (INIS)

Khaljani, M.; Saray, R. Khoshbakhti; Bahlouli, K.

2016-01-01

In this work, a combined power cycle which includes a HCCI (Homogenous Charge Compression Ignition) engine and two ORCs (Organic Rankine Cycles) is introduced. In the proposed cycle, the waste heats from the engine cooling water and exhaust gases are utilized to drive the ORCs. A parametric study is conducted to show the effects of decision parameters on the performance and on the total cost rate of cycle. Results of the parametric study reveal that increasing the pinch point temperature difference of evaporator and temperature of the condenser leads to reduction in both exergy efficiency and total cost rate of the bottoming cycle. There is a specific evaporator temperature where exergy efficiency is improved, but the total cost rate of the bottoming cycle is maximized. Also, a multi-objective optimization strategy is performed to achieve the best system design parameters from both thermodynamic and economic aspects. The exergy efficiency and the total cost rate of the system have been considered as objective functions. Optimization results indicate that the exergy efficiency of the cycle increases from 44.96% for the base case to 46.02%. Also, approximately1.3% reduction in the cost criteria is achieved. Results of the multi-objective optimization justify the results obtained through the parametric study and demonstrate that the design parameters of both ORCs have conflict effect on the objective functions. - Highlights: • Two Organic Rankine bottoming cycles are coupled with an HCCI Engine. • Exergetic and Exergo-economic analysis of the bottoming cycle are reported. • The system is optimized using multi-objective genetic algorithm. • Objective functions are exergy efficiency and total cost rate of the system. • The exergy efficiency of the cycle increases from 44.96% to 46.02%.

Comparison of Aerobic Performance Testing Protocols in Elite Male Wheelchair Basketball Players

Directory of Open Access Journals (Sweden)

Molik Bartosz

2017-12-01

Full Text Available In wheelchair sports, aerobic performance is commonly assessed with the use of an arm crank ergometer (ACE, a wheelchair ergometer (WCE or a wheelchair treadmill (WCT. There are different protocols to identify peak oxygen uptake in wheelchair sports; however, only a few protocols have been applied to evaluate these conditions in wheelchair basketball players. The purpose of this study was to compare physiological responses during maximal exercise testing with the use of ACE and WCT in wheelchair basketball players. Twelve elite male wheelchair basketball players participated in this study. The research was performed during a training camp of the Polish National Wheelchair Basketball Team. The study participants were divided into two functional categories: A (players with class 1.0 - 2.5 and B (players with class 3.0 - 4.5. Two main maximal exercise tests, i.e. wheelchair treadmill stress test (WCT test and arm crank ergometer stress test (ACE test were used to evaluate aerobic performance of the players. There were no statistically significant differences in aerobic tests between the players from both groups. The comparison of results achieved in two aerobic tests performed on WCT and ACE did not reveal any significant differences between the analyzed variables (peak heart rate (HRpeak, peak oxygen uptake (VO2peak, minute ventilation (VE, anaerobic threshold (AT, lactate concentration (LApeak, and a drop in lactate concentration (%LA. Strong correlations between results achieved in WCT and ACE tests were found for VO2peak, VE and LApeak. The main conclusion of the study is that both WCT and ACE tests may be useful when determining aerobic capacity of wheelchair basketball players. Moreover, both protocols can be used by athletes regardless of their functional capabilities and types of impairment.

CANDU-6 fuel optimization for advanced cycles

Energy Technology Data Exchange (ETDEWEB)

St-Aubin, Emmanuel, E-mail: emmanuel.st-aubin@polymtl.ca; Marleau, Guy, E-mail: guy.marleau@polymtl.ca

2015-11-15

Highlights: • New fuel selection process proposed for advanced CANDU cycles. • Full core time-average CANDU modeling with independent refueling and burnup zones. • New time-average fuel optimization method used for discrete on-power refueling. • Performance metrics evaluated for thorium-uranium and thorium-DUPIC cycles. - Abstract: We implement a selection process based on DRAGON and DONJON simulations to identify interesting thorium fuel cycles driven by low-enriched uranium or DUPIC dioxide fuels for CANDU-6 reactors. We also develop a fuel management optimization method based on the physics of discrete on-power refueling and the time-average approach to maximize the economical advantages of the candidates that have been pre-selected using a corrected infinite lattice model. Credible instantaneous states are also defined using a channel age model and simulated to quantify the hot spots amplitude and the departure from criticality with fixed reactivity devices. For the most promising fuels identified using coarse models, optimized 2D cell and 3D reactivity device supercell DRAGON models are then used to generate accurate reactor databases at low computational cost. The application of the selection process to different cycles demonstrates the efficiency of our procedure in identifying the most interesting fuel compositions and refueling options for a CANDU reactor. The results show that using our optimization method one can obtain fuels that achieve a high average exit burnup while respecting the reference cycle safety limits.

Intracyclic Velocity Variation of the Center of Mass and Hip in Breaststroke Swimming With Maximal Intensity.

Science.gov (United States)

Gourgoulis, Vassilios; Koulexidis, Stylianos; Gketzenis, Panagiotis; Tzouras, Grigoris

2018-03-01

Gourgoulis, V, Koulexidis, S, Gketzenis, P, and Tzouras, G. Intra-cyclic velocity variation of the center of mass and hip in breaststroke swimming with maximal intensity. J Strength Cond Res 32(3): 830-840, 2018-The aim of the study was to compare the center of mass (CM) and hip (HIP) intracyclic velocity variation in breaststroke swimming using 3-dimensional kinematic analysis. Nine male breaststrokes, of moderate performance level, swam 25-m breaststroke with maximal intensity, and their movements were recorded, both under and above the water surface, using 8 digital cameras. Their CM and HIP velocities and their intracyclic variations were estimated after manual digitization of 28 selected points on the body in a complete arm and leg breaststroke cycle. Paired sample t-tests or Wilcoxon tests, when the assumption of normality was broken, were used for statistical analyses. In both, CM and HIP velocity-time curves, the results revealed a similar pattern of 2 clear peaks associated with the leg and arm propulsive phases and 2 minimal velocities that corresponded to the arm and leg recovery phase and the lag time between the leg and arm propulsive phases, respectively. However, despite this similar general pattern, the HIP minimum resultant velocity was significantly lower, whereas its maximal value was significantly greater, than the corresponding CM values. Consequently, the HIP intracyclic swimming velocity fluctuation significantly overestimates the actual variation of the swimmer's velocity in breaststroke swimming.

Calprotectin is released from human skeletal muscle tissue during exercise

DEFF Research Database (Denmark)

Mortensen, Ole Hartvig; Andersen, Kasper; Fischer, Christian

2008-01-01

Skeletal muscle has been identified as a secretory organ. We hypothesized that IL-6, a cytokine secreted from skeletal muscle during exercise, could induce production of other secreted factors in skeletal muscle. IL-6 was infused for 3 h into healthy young males (n = 7) and muscle biopsies obtained...... in skeletal muscle following IL-6 infusion compared to controls. Furthermore, S100A8 and S100A9 mRNA levels were up-regulated 5-fold in human skeletal muscle following cycle ergometer exercise for 3 h at approximately 60% of in young healthy males (n = 8). S100A8 and S100A9 form calprotectin, which is known...... as an acute phase reactant. Plasma calprotectin increased 5-fold following acute cycle ergometer exercise in humans, but not following IL-6 infusion. To identify the source of calprotectin, healthy males (n = 7) performed two-legged dynamic knee extensor exercise for 3 h with a work load of approximately 50...

Assessment of the Maximal Split-Half Coefficient to Estimate Reliability

Science.gov (United States)

Thompson, Barry L.; Green, Samuel B.; Yang, Yanyun

2010-01-01

The maximal split-half coefficient is computed by calculating all possible split-half reliability estimates for a scale and then choosing the maximal value as the reliability estimate. Osburn compared the maximal split-half coefficient with 10 other internal consistency estimates of reliability and concluded that it yielded the most consistently…

Learning curves for mutual information maximization

International Nuclear Information System (INIS)

Urbanczik, R.

2003-01-01

An unsupervised learning procedure based on maximizing the mutual information between the outputs of two networks receiving different but statistically dependent inputs is analyzed [S. Becker and G. Hinton, Nature (London) 355, 161 (1992)]. For a generic data model, I show that in the large sample limit the structure in the data is recognized by mutual information maximization. For a more restricted model, where the networks are similar to perceptrons, I calculate the learning curves for zero-temperature Gibbs learning. These show that convergence can be rather slow, and a way of regularizing the procedure is considered

Thermodynamic, economic and thermo-economic optimization of a new proposed organic Rankine cycle for energy production from geothermal resources

International Nuclear Information System (INIS)

Kazemi, Neda; Samadi, Fereshteh

2016-01-01

Highlights: • A new cycle was designed to improve basic organic Rankine cycle performance. • Peng Robinson equation of state was used to obtain properties of working fluids. • Operating parameters were optimized with three different objective functions. • Efficiency of new organic Rankine cycle is higher than other considered cycles. • Return on investment of new cycle for Iran is more than France and America. - Abstract: The main goal of this study is to propose and investigate a new organic Rankine cycle based on three considered configurations: basic organic Rankine cycle, regenerative organic Rankine cycle and two-stage evaporator organic Rankine cycle in order to increase electricity generation from geothermal sources. To analyze the considered cycles’ performance, thermodynamic (energy and exergy based on the first and second laws of thermodynamics) and economic (specific investment cost) models are investigated. Also, a comparison of cycles modeling results is carried out in optimum conditions according to different optimization which consist thermodynamic, economic and thermo-economic objective functions for maximizing exergy efficiency, minimizing specific investment cost and applying a multi-objective function in order to maximize exergy efficiency and minimize specific investment cost, respectively. Optimized operating parameters of cycles include evaporators and regenerative temperatures, pinch point temperature difference of evaporators and degree of superheat. Furthermore, Peng Robinson equation of state is used to obtain thermodynamic properties of isobutane and R123 which are selected as dry and isentropic working fluids, respectively. The results of optimization indicate that, thermal and exergy efficiencies increase and exergy destruction decrease especially in evaporators for both working fluids in new proposed organic Rankine cycle compared to the basic organic Rankine cycle. Moreover, the amount of specific investment cost in new

Effect of active warm-up duration on morning short-term maximal performance during Ramadan.

Science.gov (United States)

Baklouti, Hana; Chtourou, Hamdi; Aloui, Asma; Chaouachi, Anis; Souissi, Nizar

2015-01-01

To examine the effect of active warm-up duration on short-term maximal performance assessed during Ramadan in the morning. Twelve healthy active men performed four Wingate tests for measurement of peak power and mean power before and during Ramadan at 09:00 a.m. The tests were performed on separate days, after either a 5-min or a 15-min warm-up. The warm-up consisted in pedaling at 50% of the power output obtained at the last stage of a submaximal multistage cycling test. Oral temperature was measured at rest and after warming-up. Furthermore, ratings of perceived exertion were obtained immediately after the Wingate test. Oral temperature was higher after the 15-min warm-up than the 5-min warm-up throughout the study. Moreover, peak power and mean power were higher after the 15-min warm-up than the 5-min warm-up before Ramadan. However, during Ramadan, there was no significant difference between the two warm-up durations. In addition, ratings of perceived exertion were higher after the 15-min warm-up than the 5-min warm-up only during Ramadan. There is no need to prolong the warm-up period before short-term maximal exercise performed during Ramadan in the morning.

Breakdown of maximality conjecture in continuous phase transitions

International Nuclear Information System (INIS)

Mukamel, D.; Jaric, M.V.

1983-04-01

A Landau-Ginzburg-Wilson model associated with a single irreducible representation which exhibits an ordered phase whose symmetry group is not a maximal isotropy subgroup of the symmetry group of the disordered phase is constructed. This example disproves the maximality conjecture suggested in numerous previous studies. Below the (continuous) transition, the order parameter points along a direction which varies with the temperature and with the other parameters which define the model. An extension of the maximality conjecture to reducible representations was postulated in the context of Higgs symmetry breaking mechanism. Our model can also be extended to provide a counter example in these cases. (author)

Maximizers versus satisficers: Decision-making styles, competence, and outcomes

OpenAIRE

Andrew M. Parker; Wändi Bruine de Bruin; Baruch Fischhoff

2007-01-01

Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007). Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al.\\ (2002), we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decision...

Effects of a short-term personalized Intermittent Work Exercise Program (IWEP) on maximal cardio-respiratory function and endurance parameters among healthy young and older seniors.

Science.gov (United States)

Vogel, T; Leprêtre, P-M; Brechat, P-H; Lonsdorfer, E; Benetos, A; Kaltenbach, G; Lonsdorfer, J

2011-12-01

The aim of this study was to evaluate the efficiency of a short-term Intermittent Work Exercise Program (IWEP) among healthy elderly subjects. This longitudinal prospective study took place at the Strasbourg University Hospital geriatric department. One hundred and fifty older volunteers, previously determined as being free from cardiac and pulmonary disease, were separated into two age groups: the "young senior" (60.2 ± 3.1 yr) and the "older senior" groups (70.8 ± 5.2 yr). These groups were then subdivided by gender into the "young female senior", "young male senior" "older female senior" and "older male senior" groups. Before and after the IWEP, all subjects were asked to perform an incremental cycle exercise to obtain their first ventilatory threshold (VT1), maximal tolerated power (MTP), peak oxygen uptake (VO2peak) and maximal minute ventilation (MMV). The IWEP consisted of a 30-min cycling exercise which took place twice a week, and was divided into six 5-min stages consisting of 4 min at VT1 intensity and 1 min at 90% MTP. An assessment was made of the effects of the IWEP on maximal cardio-respiratory function (MTP, VO2peak, MMV) and endurance parameters (VT1, heart rate [HR] measured at pretraining VT1 and lactate concentrations at pre-training MTP). This short-term training program resulted in a significant increase of MTP (from 13.2% to 20.6%), VO2peak (from 8.9% to 16.6%) and MMV (from 11.1% to 21.8%) in all groups (pseniors" were not significantly different (p>0.05) from the "young seniors" pre-training values for the same parameters. The most striking finding in this study is that after only 9 weeks, our short-term "individually-tailored" IWEP significantly improved both maximal cardio-respiratory function and endurance parameters in healthy, previously untrained seniors.

IMNN: Information Maximizing Neural Networks

Science.gov (United States)

Charnock, Tom; Lavaux, Guilhem; Wandelt, Benjamin D.

2018-04-01

This software trains artificial neural networks to find non-linear functionals of data that maximize Fisher information: information maximizing neural networks (IMNNs). As compressing large data sets vastly simplifies both frequentist and Bayesian inference, important information may be inadvertently missed. Likelihood-free inference based on automatically derived IMNN summaries produces summaries that are good approximations to sufficient statistics. IMNNs are robustly capable of automatically finding optimal, non-linear summaries of the data even in cases where linear compression fails: inferring the variance of Gaussian signal in the presence of noise, inferring cosmological parameters from mock simulations of the Lyman-α forest in quasar spectra, and inferring frequency-domain parameters from LISA-like detections of gravitational waveforms. In this final case, the IMNN summary outperforms linear data compression by avoiding the introduction of spurious likelihood maxima.

Neutrino mass textures with maximal CP violation

International Nuclear Information System (INIS)

Aizawa, Ichiro; Kitabayashi, Teruyuki; Yasue, Masaki

2005-01-01

We show three types of neutrino mass textures, which give maximal CP violation as well as maximal atmospheric neutrino mixing. These textures are described by six real mass parameters: one specified by two complex flavor neutrino masses and two constrained ones and the others specified by three complex flavor neutrino masses. In each texture, we calculate mixing angles and masses, which are consistent with observed data, as well as Majorana CP phases

A Conceptual Study of Using an Isothermal Compressor on a Supercritical CO_2 Brayton Cycle for SMART Application

International Nuclear Information System (INIS)

Heo, Jin Young; Lee, Jeong Ik; Ahn, Yoonhan

2016-01-01

To maximize the benefits of modularization, the supercritical CO_2 (S-CO_2) power cycle can replace the conventional steam Rankine cycle to increase the cycle efficiency and reduce its system size. Previous works have been conducted to evaluate potential advantages of applying the S-CO_2 cycle to SMRs, specifically to SMART (System-integrated Modular Advanced Reactor) which is an integral SMR developed by KAERI (Korea Atomic Energy Institute). One of the optimized S-CO_2 cycle layouts is the recompressing Brayton cycle. This paper attempts to improve the cycle layout by replacing the conventional compressor with an isothermal compressor, of which its potential in the S-CO_2 power cycle is conceptually being evaluated. The SMR applications, for which SMART reactor has been represented, can take advantage of the currently developing S-CO_2 cycle greatly by the reduction of size. By introducing the isothermal compressor, the cycle layout considered in has been further improved by increasing the cycle net efficiency by around 0.5%

Comparison of changes in the mobility of the pelvic floor muscle on during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction

OpenAIRE

Jung, Halim; Jung, Sangwoo; Joo, Sunghee; Song, Changho

2016-01-01

[Purpose] The purpose of this study was to compare changes in the mobility of the pelvic floor muscle during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction. [Subjects] Thirty healthy adults participated in this study (15 men and 15 women). [Methods] All participants performed a bridge exercise and abdominal curl-up during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction. Pelvic floor mobility...

Comparative analysis of two different methods of anaerobic capacity assessment in sedentary young men

Directory of Open Access Journals (Sweden)

Klašnja Aleksandar

2010-01-01

Full Text Available Background/Aim. The Wingate anaerobic test is a valid and reliable method of measuring anaerobic capacity. The aim of this study was to determine whether other modified test can be used instead of the Wingate test. Methods. A group of 30 sedentary young men were first tested with a cycle ergometer (classic Wingate test, and then with a dynamometer during 30 s of 'all out' leg extension exercise (modified Wingate test; WAnTe in order to test anaerobic capacity. Subsequent correlations between these tests were made. Results. Peak power, mean power on cycling ergometer in absolute and relative values were 463 ± 105 W, 316.7 ± 63.8 W, 5.68 ± 1.17 W/kg, 3.68 ± 0.78 W/kg, respectively. On a dynamometer absolute and relative values of maximal and mean load in kg and power in Watts were 136.54 ± 21.3 kg, 1.67 ± 0.26; 128.65 ± 19.93 kg, 1.57 ± 0.24 kg, 657 ± 125.87 W, and 8 ± 1.54 W/kg, respectively. There was no correlation between 5 s intervals of the classic Wingate test and WAnTe during the first, fourth and fifth intervals, but in the second (r = 0.49, p < 0.05, third (r = 0.38, p < 0.05 and last 5 s intervals (r = 0.39, p < 0.05, and also in peak power and mean power (r = 0.42, p < 0.05 and r = 0.45, p < 0.05 respectively, a significant positive correlation was detected. Conclusion. A modified Wingate test of leg extension on a dynamometer in sedentary young men shows a correlation with the classic Wingate test only in parameters of peak power, and mean power and the second, the third and the last 5 s intervals. Because of that it should only be used for orientation, whereas for precise measurements of anaerobic capacity the classic Wingate test should be used.

Optimization of the triple-pressure combined cycle power plant

Directory of Open Access Journals (Sweden)

Alus Muammer

2012-01-01

Full Text Available The aim of this work was to develop a new system for optimization of parameters for combined cycle power plants (CCGTs with triple-pressure heat recovery steam generator (HRSG. Thermodynamic and thermoeconomic optimizations were carried out. The objective of the thermodynamic optimization is to enhance the efficiency of the CCGTs and to maximize the power production in the steam cycle (steam turbine gross power. Improvement of the efficiency of the CCGT plants is achieved through optimization of the operating parameters: temperature difference between the gas and steam (pinch point P.P. and the steam pressure in the HRSG. The objective of the thermoeconomic optimization is to minimize the production costs per unit of the generated electricity. Defining the optimal P.P. was the first step in the optimization procedure. Then, through the developed optimization process, other optimal operating parameters (steam pressure and condenser pressure were identified. The developed system was demonstrated for the case of a 282 MW CCGT power plant with a typical design for commercial combined cycle power plants. The optimized combined cycle was compared with the regular CCGT plant.

Increased cross-bridge recruitment contributes to transient increase in force generation beyond maximal capacity in human myocardium.

Science.gov (United States)

Milani-Nejad, Nima; Chung, Jae-Hoon; Canan, Benjamin D; Fedorov, Vadim V; Whitson, Bryan A; Kilic, Ahmet; Mohler, Peter J; Janssen, Paul M L

2018-01-01

Cross-bridge attachment allows force generation to occur, and rate of tension redevelopment (k tr ) is a commonly used index of cross-bridge cycling rate. Tension overshoots have been observed briefly after a slack-restretch k tr maneuver in various species of animal models and humans. In this study, we set out to determine the properties of these overshoots and their possible underlying mechanism. Utilizing human cardiac trabeculae, we have found that tension overshoots are temperature-dependent and that they do not occur at resting states. In addition, we have found that myosin cross-bridge cycle is vital to these overshoots as inhibition of the cycle results in the blunting of the overshoots and the magnitude of the overshoots are dependent on the level of myofilament activation. Lastly, we show that the number of cross-bridges transiently increase during tension overshoots. These findings lead us to conclude that tension overshoots are likely due to a transient enhancement of the recruitment of myosin heads into the cross-bridge cycling, regulated by the myocardium, and with potential physiological significance in determining cardiac output. We show that isolated human myocardium is capable of transiently increasing its maximal force generation capability by increasing cross-bridge recruitment following slack-restretch maneuver. This process can potentially have important implications and significance in cardiac contraction in vivo. Copyright © 2017 Elsevier Ltd. All rights reserved.

International comparisons of the associations between objective measures of the built environment and transport-related walking and cycling

DEFF Research Database (Denmark)

Christiansen, Lars B; Cerin, Ester; Badland, Hannah

2016-01-01

with transport-related walking and cycling. METHODS: This cross-sectional study maximized variation of environments and demographics by including multiple countries and by selecting adult participants living in neighborhoods based on higher and lower classifications of objectively measured walkability...

Maximally-localized position, Euclidean path-integral, and thermodynamics in GUP quantum mechanics

Science.gov (United States)

Bernardo, Reginald Christian S.; Esguerra, Jose Perico H.

2018-04-01

In dealing with quantum mechanics at very high energies, it is essential to adapt to a quasiposition representation using the maximally-localized states because of the generalized uncertainty principle. In this paper, we look at maximally-localized states as eigenstates of the operator ξ = X + iβP that we refer to as the maximally-localized position. We calculate the overlap between maximally-localized states and show that the identity operator can be expressed in terms of the maximally-localized states. Furthermore, we show that the maximally-localized position is diagonal in momentum-space and that the maximally-localized position and its adjoint satisfy commutation and anti-commutation relations reminiscent of the harmonic oscillator commutation and anti-commutation relations. As application, we use the maximally-localized position in developing the Euclidean path-integral and introduce the compact form of the propagator for maximal localization. The free particle momentum-space propagator and the propagator for maximal localization are analytically evaluated up to quadratic-order in β. Finally, we obtain a path-integral expression for the partition function of a thermodynamic system using the maximally-localized states. The partition function of a gas of noninteracting particles is evaluated. At temperatures exceeding the Planck energy, we obtain the gas' maximum internal energy N / 2 β and recover the zero heat capacity of an ideal gas.

Why firms should not always maximize profits

OpenAIRE

Kolstad, Ivar

2006-01-01

Though corporate social responsibility (CSR) is on the agenda of most major corporations, corporate executives still largely support the view that corporations should maximize the returns to their owners. There are two lines of defence for this position. One is the Friedmanian view that maximizing owner returns is the corporate social responsibility of corporations. The other is a position voiced by many executives, that CSR and profits go together. This paper argues that the first position i...

Life Cycle Management Managing the Aging of Critical Nuclear Plant Components

International Nuclear Information System (INIS)

Meyer, Theodore A.; Elder, G. Gary; Llovet, Ricardo

2002-01-01

Life Cycle Management is a structured process to manage equipment aging and long-term equipment reliability for nuclear plant Systems, Structures and Components (SSCs). The process enables the identification of effective repair, replace, inspect, test and maintenance activities and the optimal timing of the activities to maximize the economic value to the nuclear plant. This paper will provide an overview of the process and some of the tools that can be used to implement the process for the SSCs deemed critical to plant safety and performance objectives. As nuclear plants strive to reduce costs, extend life and maximize revenue, the LCM process and the supporting tools summarized in this paper can enable development of a long term, cost efficient plan to manage the aging of the plant SSCs. (authors)

No differences in cycling efficiency between world-class and recreational cyclists.

Science.gov (United States)

Moseley, L; Achten, J; Martin, J C; Jeukendrup, A E

2004-07-01

The aim of this experiment was to compare the efficiency of elite cyclists with that of trained and recreational cyclists. Male subjects (N = 69) performed an incremental exercise test to exhaustion on an electrically braked cycle ergometer. Cadence was maintained between 80 - 90 rpm. Energy expenditure was estimated from measures of oxygen uptake (VO (2)) and carbon dioxide production (VCO(2)) using stoichiometric equations. Subjects (age 26 +/- 7 yr, body mass 74.0 +/- 6.3 kg, Wpeak 359 +/- 40 W and VO(2)peak 62.3 +/- 7.0 mL/kg/min) were divided into 3 groups on the basis of their VO (2)peak ( 70 (High, N = 16) mL/kg/min). All data are mean +/- SE. Despite the wide range in aerobic capacities gross efficiency (GE) at 165 W (GE (165)), GE at the same relative intensity (GE (final)), delta efficiency (DE) and economy (EC) were similar between all groups. Mean GE (165) was 18.6 +/- 0.3 %, 18.8 +/- 0.4 % and 17.9 +/- 0.3 % while mean DE was 22.4 +/- 0.4 %, 21.6 +/- 0.4 % and 21.2 +/- 0.5 % (for Low, Medium and High, respectively). There was no correlation between GE (165), GE (final), DE or EC and VO(2)peak. Based on these data, we conclude that there are no differences in efficiency and economy between elite cyclists and recreational level cyclists.

Power Optimization of Organic Rankine-cycle System with Low-Temperature Heat Source Using HFC-134a

Energy Technology Data Exchange (ETDEWEB)

Baik, Young Jin; Kim, Min Sung; Chang, Ki Chang; Lee, Young Soo; Ra, Ho Sang [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

2011-01-15

In this study, an organic Rankine-cycle system using HFC-134a, which is a power cycle corresponding to a low temperature heat source, such as that for geothermal power generation, was investigated from the view point of power optimization. In contrast to conventional approaches, the heat transfer and pressure drop characteristics of the working fluid within the heat exchangers were taken into account by using a discretized heat exchanger model. The inlet flow rates and temperatures of both the heat source and the heat sink were fixed. The total heat transfer area was fixed, whereas the heat-exchanger areas of the evaporator and the condenser were allocated to maximize the power output. The power was optimized on the basis of three design parameters. The optimal combination of parameters that can maximize power output was determined on the basis of the results of the study. The results also indicate that the evaporation process has to be optimized to increase the power output.

Effect of estrogen supplementation on exercise thermoregulation in premenopausal women.

Science.gov (United States)

Chang, R T; Lambert, G P; Moseley, P L; Chapler, F K; Gisolfi, C V

1998-12-01

This study examined the effects of 3 days of estrogen supplementation (ES) on thermoregulation during exercise in premenopausal (20-39 yr) adult women during the follicular phase of the menstrual cycle. Subjects (11 control, 10 experimental) performed upright cycle ergometer exercise at 60% of maximal O2 consumption in a neutral environment (25 degreesC, 30% relative humidity) for 20 min. Subjects were given placebo (P) or beta-estradiol (2 mg/tablet, 3 tablets/day for 3 days). All experiments were conducted between 6:30 and 9:00 AM after ingestion of the last tablet. Heart rate, forearm blood flow (FBF), mean skin temperature, esophageal temperature (Tes), and forearm sweat rate were measured. Blood analysis for estrogen and progesterone reflected the follicular phase of the menstrual cycle. Maximal O2 consumption (37.1 +/- 6.2 in P vs. 38.4 +/- 6.3 ml. kg-1. min-1 in ES) and body weight-to-surface area ratio (35.58 +/- 2.85 in P vs. 37.3 +/- 2.7 in ES) were similar between groups. Synthesis of 70-kDa heat shock protein was not induced by 3 days of ES. Neither the threshold for sweating (36.97 +/- 0.15 in P vs. 36.90 +/- 0.22 degreesC in ES), the threshold for an increase in FBF (37.09 +/- 0. 22 in P vs. 37.17 +/- 0.26 degreesC in ES), the slope of sweat rate-Tes relationship (0.42 +/- 0.16 in P vs. 0.41 +/- 0.17 in ES), nor the FBF-Tes relationship (10.04 +/- 4.4 in P vs. 9.61 +/- 3.46 in ES) was affected (P > 0.05) by 3 days of ES. We conclude that 3 days of ES by young adult women in the follicular phase of their menstrual cycle have no effect on heat transfer to the skin, heat dissipation by evaporative cooling, or leukocyte synthesis of 70-kDa heat shock protein.

Maximizing band gaps in plate structures

DEFF Research Database (Denmark)

Halkjær, Søren; Sigmund, Ole; Jensen, Jakob Søndergaard

2006-01-01

periodic plate using Bloch theory, which conveniently reduces the maximization problem to that of a single base cell. Secondly, we construct a finite periodic plate using a number of the optimized base cells in a postprocessed version. The dynamic properties of the finite plate are investigated......Band gaps, i.e., frequency ranges in which waves cannot propagate, can be found in elastic structures for which there is a certain periodic modulation of the material properties or structure. In this paper, we maximize the band gap size for bending waves in a Mindlin plate. We analyze an infinite...... theoretically and experimentally and the issue of finite size effects is addressed....

Finding Maximal Pairs with Bounded Gap

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Lyngsø, Rune B.; Pedersen, Christian N. S.

1999-01-01

. In this paper we present methods for finding all maximal pairs under various constraints on the gap. In a string of length n we can find all maximal pairs with gap in an upper and lower bounded interval in time O(n log n+z) where z is the number of reported pairs. If the upper bound is removed the time reduces...... to O(n+z). Since a tandem repeat is a pair where the gap is zero, our methods can be seen as a generalization of finding tandem repeats. The running time of our methods equals the running time of well known methods for finding tandem repeats....

Energy expenditure evaluation in humans and non-human primates by SenseWear Armband. Validation of energy expenditure evaluation by SenseWear Armband by direct comparison with indirect calorimetry.

Science.gov (United States)

Casiraghi, Francesca; Lertwattanarak, Raweewan; Luzi, Livio; Chavez, Alberto O; Davalli, Alberto M; Naegelin, Terry; Comuzzie, Anthony G; Frost, Patricia; Musi, Nicolas; Folli, Franco

2013-01-01

The purpose of this study was to compare and validate the use of SenseWear Armband (SWA) placed on the arm (SWA ARM) and on the back (SWA BACK) in healthy humans during resting and a cycle-ergometer exercise and to evaluate the SWA to estimate Resting Energy Expenditure (REE) and Total Energy Expenditure (TEE) in healthy baboons. We studied 26 (15F/11M) human subjects wearing SWA in two different anatomical sites (arm and back) during resting and a cycle-ergometer test and directly compared these results with indirect calorimetry evaluation (IC), performed at the same time. We then inserted the SWA in a metabolic jacket for baboons and evaluated the TEE and REE in free living condition for 6 days in 21 (8F/13M) non-human primates. In humans we found a good correlation between SWA place on the ARM and on the BACK with IC during the resting experiment (1.1±0.3 SWAs, 1±0.2 IC kcal/min) and a slight underestimation in the SWAs data compared with IC during the cycle-ergometer exercise (5±1.9 SWA ARM, 4.5±1.5 SWA BACK and 5.4±2.1 IC kcal/min). In the non-human primate (baboons) experiment SWA estimated a TEE of 0.54±0.009 kcal/min during free living and a REE of 0.82±0.06 kcal/min. SWA, an extremely simple and inexpensive apparatus, provides quite accurate measurements of energy expenditure in humans and in baboons. Energy expenditure data obtained with SWA are highly correlated with the data obtained with "gold standard", IC, in humans.

Kinetic theory in maximal-acceleration invariant phase space

International Nuclear Information System (INIS)

Brandt, H.E.

1989-01-01

A vanishing directional derivative of a scalar field along particle trajectories in maximal acceleration invariant phase space is identical in form to the ordinary covariant Vlasov equation in curved spacetime in the presence of both gravitational and nongravitational forces. A natural foundation is thereby provided for a covariant kinetic theory of particles in maximal-acceleration invariant phase space. (orig.)

Half-maximal supersymmetry from exceptional field theory

Energy Technology Data Exchange (ETDEWEB)

Malek, Emanuel [Arnold Sommerfeld Center for Theoretical Physics, Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen (Germany)

2017-10-15

We study D ≥ 4-dimensional half-maximal flux backgrounds using exceptional field theory. We define the relevant generalised structures and also find the integrability conditions which give warped half-maximal Minkowski{sub D} and AdS{sub D} vacua. We then show how to obtain consistent truncations of type II / 11-dimensional SUGRA which break half the supersymmetry. Such truncations can be defined on backgrounds admitting exceptional generalised SO(d - 1 - N) structures, where d = 11 - D, and N is the number of vector multiplets obtained in the lower-dimensional theory. Our procedure yields the most general embedding tensors satisfying the linear constraint of half-maximal gauged SUGRA. We use this to prove that all D ≥ 4 half-maximal warped AdS{sub D} and Minkowski{sub D} vacua of type II / 11-dimensional SUGRA admit a consistent truncation keeping only the gravitational supermultiplet. We also show to obtain heterotic double field theory from exceptional field theory and comment on the M-theory / heterotic duality. In five dimensions, we find a new SO(5, N) double field theory with a (6 + N)-dimensional extended space. Its section condition has one solution corresponding to 10-dimensional N = 1 supergravity and another yielding six-dimensional N = (2, 0) SUGRA. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of task familiarisation on distribution of energy during a 2000 m cycling time trial.

Science.gov (United States)

Corbett, J; Barwood, M J; Parkhouse, K

2009-10-01

To investigate the effect of task familiarisation on the spontaneous pattern of energy expenditure during a series of 2000 m cycling time trials (TTs). Nine trained males completed three 2000 m TTs on a Velotron cycling ergometer. To examine pacing strategy, the data were assigned to 250 m "bins," with the pattern of aerobic and anaerobic energy expenditure calculated from total work accomplished and gas-exchange data. There were no significant differences between trials in performance times (191.4 (SD 4.3), 189.4 (4.6), 190.1 (5.6) s), total aerobic (58.3 (2.7), 58.4 (3.1), 58.0 (3.4) kJ) and total anaerobic energy expenditure (16.4 (3.3), 17.3 (2.8), 16.5 (3.1) kJ). Pacing strategy in the second and third TT differed from the first TT in that a lower power output was adopted during the first 500 m, enabling a higher power output during the final 750 m of the TT. This adjustment in the pattern of energy expenditure was mediated by an alteration in the pattern of anaerobic energy expenditure, which paralleled changes in total energy expenditure. Furthermore, participants retained an anaerobic energy "reserve" enabling an end-spurt during the second and third trials. Small modifications to the pacing strategy are made following a single bout of exercise, primarily by altering the rate of anaerobic energy expenditure. This may have served to prevent critical metabolic disturbances. The alteration in pacing strategy following the first exercise bout is compatible with a complex intelligent regulatory system.

Coffee and Caffeine Ingestion Have Little Effect on Repeated Sprint Cycling in Relatively Untrained Males

Directory of Open Access Journals (Sweden)

Neil Clarke

2016-08-01

Full Text Available The present study investigated the effect of ingesting caffeine-dose-matched anhydrous caffeine or coffee on the performance of repeated sprints. Twelve recreationally active males (mean ± SD age: 22 ± 2 years, height: 1.78 ± 0.07 m, body mass: 81 ± 16 kg completed eighteen 4 s sprints with 116 s recovery on a cycle ergometer on four separate occasions in a double-blind, randomised, counterbalanced crossover design. Participants ingested either 3 mg·kg−1 of caffeine (CAF, 0.09 g·kg−1 coffee, which provided 3 mg·kg−1 of caffeine (COF, a taste-matched placebo beverage (PLA, or a control condition (CON 45 min prior to commencing the exercise protocol. Peak and mean power output and rating of perceived exertion (RPE were recorded for each sprint. There were no significant differences in peak power output (CAF: 949 ± 199 W, COF: 949 ± 174 W, PLA: 971 ± 149 W and CON: 975 ± 170 W; p = 0.872; η P 2 = 0.02 or mean power output (CAF: 873 ± 172 W, COF: 862 ± 44 W, PLA: 887 ± 119 W and CON: 892 ± 143 W; p = 0.819; η P 2 = 0.03 between experimental conditions. Mean RPE was similar for all trials (CAF: 11 ± 2, COF: 11 ± 2, PLA: 11 ± 2 and CON: 11 ± 2; p = 0.927; η P 2 = 0.01. Neither the ingestion of COF or CAF improved repeated sprint cycling performance in relatively untrained males.

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.

Directory of Open Access Journals (Sweden)

Jonathan M Oliver

Full Text Available Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA, or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10% with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM. Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9% and LMW (1.9%, 90%CI 0.8%, 3.0% carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0% almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%. Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered

Isometric quadriceps strength determines sailing performance and neuromuscular fatigue during an upwind sailing emulation.

Science.gov (United States)

Bourgois, Jan G; Callewaert, Margot; Celie, Bert; De Clercq, Dirk; Boone, Jan

2016-01-01

This study investigates the physiological responses to upwind sailing on a laser emulation ergometer and analyses the components of the physical profile that determine the physiological responses related to sailing level. Ten male high-level laser sailors performed an upwind sailing test, incremental cycling test and quadriceps strength test. During the upwind sailing test, heart rate (HR), oxygen uptake, ventilation, respiratory exchange ratio, rating of perceived exertion (RPE) and lactate concentration were measured, combined with near-infrared spectroscopy (NIRS) and electromyography (EMG) registration of the M. Vastus lateralis. Repeated measures ANOVA showed for the cardio-respiratory, metabolic and muscles responses (mean power frequency [MPF], root mean square [RMS], deoxy[Hb+Mb]) during the upwind sailing test an initial significant increase followed by a stabilisation, despite a constant increase in RPE. Stepwise regression analysis showed that better sailing level was for 46.5% predicted by lower MPF decrease. Lower MPF decrease was for 57.8% predicted by a higher maximal isometric quadriceps strength. In conclusion, this study indicates that higher sailing level was mainly determined by a lower rate of neuromuscular fatigue during the upwind sailing test (as indicated by MPF decrease). Additionally, the level of neuromuscular fatigue was mainly determined by higher maximal isometric quadriceps strength stressing the importance of resistance training in the planning of training.

Maximal slicing of D-dimensional spherically symmetric vacuum spacetime

International Nuclear Information System (INIS)

Nakao, Ken-ichi; Abe, Hiroyuki; Yoshino, Hirotaka; Shibata, Masaru

2009-01-01

We study the foliation of a D-dimensional spherically symmetric black-hole spacetime with D≥5 by two kinds of one-parameter families of maximal hypersurfaces: a reflection-symmetric foliation with respect to the wormhole slot and a stationary foliation that has an infinitely long trumpetlike shape. As in the four-dimensional case, the foliations by the maximal hypersurfaces avoid the singularity irrespective of the dimensionality. This indicates that the maximal slicing condition will be useful for simulating higher-dimensional black-hole spacetimes in numerical relativity. For the case of D=5, we present analytic solutions of the intrinsic metric, the extrinsic curvature, the lapse function, and the shift vector for the foliation by the stationary maximal hypersurfaces. These data will be useful for checking five-dimensional numerical-relativity codes based on the moving puncture approach.

Left ventricle expands maximally preceding end-diastole. Radionuclide ventriculography study

International Nuclear Information System (INIS)

Horinouchi, Osamu

2002-01-01

It has been considered that left ventricle (LV) expands maximally at the end-diastole. However, is it exactly coincident with this point? This study was aimed to determine whether the maximal expansion of LV coincides with the peak of R wave on electrocardiogram. Thirty-three angina pectoris patients with normal LV motion were examined using radionuclide ventriculography. Data were obtained from every 30 ms backward frame from the peak of R wave. All patients showed the time of maximal expansion preceded the peak of R wave. The intervals from the peak of R wave and the onset of P wave to maximal expansion of LV was 105±29 ms and 88±25 ms, respectively. This period corresponds to the timing of maximal excurtion of mitral valve by atrial contraction, and the centripetal motion of LV without losing its volume before end-diastole may be interpreted on account of the movement of mitral valve toward closure. These findings suggest that LV expands maximally between P and R wave after atrial contraction, preceding the peak of R wave thought conventionally as the end-diastole. (author)

Candidate gene analysis using imputed genotypes: cell cycle single-nucleotide polymorphisms and ovarian cancer risk

DEFF Research Database (Denmark)

Goode, Ellen L; Fridley, Brooke L; Vierkant, Robert A

2009-01-01

Polymorphisms in genes critical to cell cycle control are outstanding candidates for association with ovarian cancer risk; numerous genes have been interrogated by multiple research groups using differing tagging single-nucleotide polymorphism (SNP) sets. To maximize information gleaned from......, and rs3212891; CDK2 rs2069391, rs2069414, and rs17528736; and CCNE1 rs3218036. These results exemplify the utility of imputation in candidate gene studies and lend evidence to a role of cell cycle genes in ovarian cancer etiology, suggest a reduced set of SNPs to target in additional cases and controls....

Comparison between regenerative organic Rankine cycle (RORC) and basic organic Rankine cycle (BORC) based on thermoeconomic multi-objective optimization considering exergy efficiency and levelized energy cost (LEC)

International Nuclear Information System (INIS)

Feng, Yongqiang; Zhang, Yaning; Li, Bingxi; Yang, Jinfu; Shi, Yang

2015-01-01

Highlights: • The thermoeconomic comparison of regenerative RORC and BORC is investigated. • The Pareto frontier solution with bi-objective compares with the corresponding single-objective solutions. • The three-objective optimization of the RORC and BORC is studied. • The RORC owns 8.1% higher exergy efficiency and 21.1% more LEC than the BORC under the Pareto-optimal solution. - Abstract: Based on the thermoeconomic multi-objective optimization by using non-dominated sorting genetic algorithm (NSGA-II), considering both thermodynamic performance and economic factors, the thermoeconomic comparison of regenerative organic Rankine cycles (RORC) and basic organic Rankine cycles (BORC) are investigated. The effects of five key parameters including evaporator outlet temperature, condenser temperature, degree of superheat, pinch point temperature difference and degree of supercooling on the exergy efficiency and levelized energy cost (LEC) are examined. Meanwhile, the Pareto frontier solution with bi-objective for maximizing exergy efficiency and minimizing LEC is obtained and compared with the corresponding single-objective solutions. Research demonstrates that there is a significant negative correlation between thermodynamic performance and economic factors. And the optimum exergy efficiency and LEC for the Pareto-optimal solution of the RORC are 55.97% and 0.142 $/kW h, respectively, which are 8.1% higher exergy efficiency and 21.1% more LEC than that of the BORC under considered condition. Highest exergy and thermal efficiencies are accompanied with lowest net power output and worst economic performance. Furthermore, taking the net power output into account, detailed investigation on the three-objective optimization for maximizing exergy efficiency, maximizing net power output and minimizing LEC is discussed

CANDU fuel cycle options in Korea

International Nuclear Information System (INIS)

Boczar, P.G.; Fehrenbach, P.J.; Meneley, D.A.

1996-04-01

The easiest first step in CANDU fuel-cycle evolution may be the use of slightly enriched uranium (SEU), including recovered uranium from reprocessed LWR spent fuel. Relatively low enrichment (up to 1.2%) will result in a twoto three-fold reduction in the quantity of spent fuel per unit energy production, reductions in fuel-cycle costs, and greater flexibility in the design of new reactors. The CANFLEX (CANDU FLEXible) fuel bundle would be the optimal fuel carrier. A country that has both CANDU and PWR reactors can exploit the natural synergism between these two reactor types to minimize overall waste production, and maximize energy derived from the fuel. This synergism can be exploited through several different fuel cycles. A high burnup CANDU MOX fuel design could be used to utilize plutonium from conventional reprocessing or more advanced reprocessing options (such as co-processing). DUPIC (Direct Use of Spent PWR Fuel In CANDU) represents a recycle option that has a higher degree of proliferation resistance than does conventional reprocessing, since it uses only dry processes for converting spent PWR fuel into CANDU fuel, without separating the plutonium. Good progress is being made in the current KAERI, AECL, and U.S. Department of State program in demonstrating the technical feasibility of DUPIC. In the longer term, CANDU reactors offer even more dramatic synergistic fuel cycles with PWR or FBR reactors. If the objective of a national fuel-cycle program is the minimization of actinide waste or destruction of long-lived fission products, then studies have shown the superiority of CANDU reactors in meeting this objective. Long-term energy security can be assured either through the thorium cycle or through a CANDU 1 FBR system, in which the FBR would be operated as a 'fuel factory,' providing the fissile material to power a number of lower-cost, high efficiency CANDU reactors. In summary, the CANDU reactor's simple fuel design, high neutron economy, and on

Psychophysiological effects of audiovisual stimuli during cycle exercise.

Science.gov (United States)

Barreto-Silva, Vinícius; Bigliassi, Marcelo; Chierotti, Priscila; Altimari, Leandro R

2018-05-01

Immersive environments induced by audiovisual stimuli are hypothesised to facilitate the control of movements and ameliorate fatigue-related symptoms during exercise. The objective of the present study was to investigate the effects of pleasant and unpleasant audiovisual stimuli on perceptual and psychophysiological responses during moderate-intensity exercises performed on an electromagnetically braked cycle ergometer. Twenty young adults were administered three experimental conditions in a randomised and counterbalanced order: unpleasant stimulus (US; e.g. images depicting laboured breathing); pleasant stimulus (PS; e.g. images depicting pleasant emotions); and neutral stimulus (NS; e.g. neutral facial expressions). The exercise had 10 min of duration (2 min of warm-up + 6 min of exercise + 2 min of warm-down). During all conditions, the rate of perceived exertion and heart rate variability were monitored to further understanding of the moderating influence of audiovisual stimuli on perceptual and psychophysiological responses, respectively. The results of the present study indicate that PS ameliorated fatigue-related symptoms and reduced the physiological stress imposed by the exercise bout. Conversely, US increased the global activity of the autonomic nervous system and increased exertional responses to a greater degree when compared to PS. Accordingly, audiovisual stimuli appear to induce a psychophysiological response in which individuals visualise themselves within the story presented in the video. In such instances, individuals appear to copy the behaviour observed in the videos as if the situation was real. This mirroring mechanism has the potential to up-/down-regulate the cardiac work as if in fact the exercise intensities were different in each condition.

Physiological profiles of young boys training in ballet.

Science.gov (United States)

Pekkarinen, H; Litmanen, H; Mahlamäki, S

1989-01-01

In order to evaluate physiological characteristics in young male ballet dancers, 27 boys (aged 9 to 16 years) who participated in a boys' dance course during the Kuopio Dance and Music Festival in June 1988 were studied. In general, the boys had started dancing at the age of 8.6 years and had been training for 4.1 years. They had, on average, three dancing sessions per week and the mean time spent on dancing was four hours per week. In the study, some anthropometric measurements were taken, the maximal oxygen uptake (VO2 max) was measured by a cycle ergometer test and the explosive strength and the mechanical power of lower extremities were evaluated by a jumping test. The results indicate that boys who train in ballet are in general moderately lean, have relatively small body size and a high degree of flexibility. The younger boys especially have only moderate aerobic power, but both explosive strength and mechanical power in leg muscles are good in ballet trained boys. PMID:2630002

CATECHOLAMINES AND β2-ADRENOCEPTOR GENE EXPRESSION BEFORE AND AFTER MAXIMAL INCREMENTAL CYCLE TEST IN YOUNG ICE HOCKEY PLAYERS: RELATION TO WORK PERFORMED

Directory of Open Access Journals (Sweden)

Urszula Mazurek

2013-04-01

Full Text Available The aim of this study was to assess the plasma adrenaline and noradrenaline concentrations as well as whole blood β2-adrenoceptor gene (ADRB2 expression in young ice hockey players before and immediately after exercise in relation to performed work. Nineteen Youth National Team ice hockey players were subjected to the maximal incremental cycloergometer exercise. The test was done in the pre-competitive phase of training. Among many parameters the plasma adrenaline and noradrenaline concentrations and ADRB2 gene expression in peripheral blood mononuclear cells (PBMC were determined before and after exercise. The average performed work was 3261.3 ± 558.3 J · kg-1 and maximal oxygen consumption (VO2max for all players was 53.85 ± 3.91 mL · kg-1 min-1. The geometric mean of the ADRB2 gene expression was statistically significantly different before and after exercise (P ≤ 0.05, while adrenaline and noradrenaline levels in plasma significantly increased after exercise. In the analysed group of athletes we found that initial level of plasma noradrenaline correlated with the performed work (r = - 0.55, P < 0.014 and normalized ADRB2 expression before the exercise correlated with the work done by them (r = 0.48, P<0.039. However, no statistically significant correlations were found between the plasma adrenaline or noradrenaline concentrations and ADRB2 gene expression in peripheral blood of the players. The performed work in the maximal incremental exercise test of regularly training young ice hockey players depends on the initial levels of noradrenaline in plasma and ADRB2 mRNA in PBMC.

Cerebral desaturation during exercise reversed by O2 supplementation

DEFF Research Database (Denmark)

Nielsen, H B; Boushel, Robert Christopher; Madsen, P

1999-01-01

microM) and DeltaHbO2 (-12 +/- 3 microM) were similar to those established without O2 supplementation, work capacity increased from 389 +/- 11 to 413 +/- 10 W (P cerebral......The combined effects of hyperventilation and arterial desaturation on cerebral oxygenation (ScO2) were determined using near-infrared spectroscopy. Eleven competitive oarsmen were evaluated during a 6-min maximal ergometer row. The study was randomized in a double-blind fashion with an inspired O2...

Maximization of regional probabilities using Optimal Surface Graphs

DEFF Research Database (Denmark)

Arias Lorza, Andres M.; Van Engelen, Arna; Petersen, Jens

2018-01-01

Purpose: We present a segmentation method that maximizes regional probabilities enclosed by coupled surfaces using an Optimal Surface Graph (OSG) cut approach. This OSG cut determines the globally optimal solution given a graph constructed around an initial surface. While most methods for vessel...... wall segmentation only use edge information, we show that maximizing regional probabilities using an OSG improves the segmentation results. We applied this to automatically segment the vessel wall of the carotid artery in magnetic resonance images. Methods: First, voxel-wise regional probability maps...... were obtained using a Support Vector Machine classifier trained on local image features. Then, the OSG segments the regions which maximizes the regional probabilities considering smoothness and topological constraints. Results: The method was evaluated on 49 carotid arteries from 30 subjects...

Planning the annual cycle in groups of cadet combat sports perfection

Directory of Open Access Journals (Sweden)

Ananchenko Konstantin

2016-08-01

Full Text Available Within a large training cycle in conditions of high general level of stress the authors recommend optimal implementation of planning undulating dynamics of cadets’ combat exercise stress. The article proves the efficiency of one-cycle construction of training highly- qualified single-combat cadets at the stage of maximal realization of sporting possibilities, which includes both features of traditional cycles (preparatory, competitional, transitional and module-sectional composition of training. It scientifically substantiates, that the choice of those or other types of microcycles which present the structure of mesocycles is determined by a few basic factors which must be necessarily taken into account while planning the training process of sportsmen of different qualification. It is suggested to use certain varieties of microcycles in the practice of preparation of single combat cadets. It is substantiated that accounting in planning the annual cycle in groups of sporting perfection of students of the educed types of microcycles for every type of single combats is an actual task of further scientific research.

Singularity Structure of Maximally Supersymmetric Scattering Amplitudes

DEFF Research Database (Denmark)

Arkani-Hamed, Nima; Bourjaily, Jacob L.; Cachazo, Freddy

2014-01-01

We present evidence that loop amplitudes in maximally supersymmetric (N=4) Yang-Mills theory (SYM) beyond the planar limit share some of the remarkable structures of the planar theory. In particular, we show that through two loops, the four-particle amplitude in full N=4 SYM has only logarithmic ...... singularities and is free of any poles at infinity—properties closely related to uniform transcendentality and the UV finiteness of the theory. We also briefly comment on implications for maximal (N=8) supergravity theory (SUGRA)....

Identities on maximal subgroups of GLn(D)

International Nuclear Information System (INIS)

Kiani, D.; Mahdavi-Hezavehi, M.

2002-04-01

Let D be a division ring with centre F. Assume that M is a maximal subgroup of GL n (D), n≥1 such that Z(M) is algebraic over F. Group identities on M and polynomial identities on the F-linear hull F[M] are investigated. It is shown that if F[M] is a PI-algebra, then [D:F] n (D) and M is a maximal subgroup of N. If M satisfies a group identity, it is shown that M is abelian-by-finite. (author)

Adaptive maximal poisson-disk sampling on surfaces

KAUST Repository

Yan, Dongming

2012-01-01

In this paper, we study the generation of maximal Poisson-disk sets with varying radii on surfaces. Based on the concepts of power diagram and regular triangulation, we present a geometric analysis of gaps in such disk sets on surfaces, which is the key ingredient of the adaptive maximal Poisson-disk sampling framework. Moreover, we adapt the presented sampling framework for remeshing applications. Several novel and efficient operators are developed for improving the sampling/meshing quality over the state-of-theart. © 2012 ACM.

Individual heat stress response

NARCIS (Netherlands)

Havenith, G.

1997-01-01

In 5 experiments, heterogeneous subject groups (large variations in _VO2 max, regular daily activity level, mass, body surface area (AD), % body fat, and AD/mass ratio) were tested for their physiological response while exercising on a cycle ergometer at a relative (45% _VO2 max; REL) or an absolute

Responses of proenkephalin Peptide F to aerobic exercise stress in the plasma and white blood cell biocompartments.

Science.gov (United States)

Kraemer, William J; Fragala, Maren S; van Henegouwen, Wendy R H Beijersbergen; Gordon, Scott E; Bush, Jill A; Volek, Jeff S; Triplett, N Travis; Dunn-Lewis, Courtenay; Comstock, Brett A; Szivak, Tunde K; Flanagan, Shawn D; Hooper, David R; Luk, Hui-Ying; Mastro, Andrea M

2013-04-01

Proenkephalin Peptide F [107-140] is an enkephalin-containing peptide found predominantly within the adrenal medulla, co-packaged with epinephrine within the chromaffin granules. In vivo studies indicate that Peptide F has classic opioid analgesia effects; in vitro studies suggest potential immune cell interactions. In this investigation we examined patterns of Peptide F concentrations in different bio-compartments of the blood at rest and following sub-maximal cycle exercise to determine if Peptide F interacts with the white blood cell (WBC) bio-compartment during aerobic exercise. Eight physically active men (n=8) performed sub-maximal (80-85% V˙O2peak) cycle ergometer exercise for 30 min. Plasma Peptide F and WBC Peptide F immunoreactivity were examined pre-exercise, mid-exercise and immediately post-, 5-min post-, 15-min post-, 30-min post- and 60-min post-exercise and at similar time-points during a control condition (30 min rest). Peptide F concentrations significantly (pexercise, compared to pre-exercise concentrations. No significant increases in Peptide F concentrations in the WBC fraction were observed during or after exercise. However, a significant decrease was observed at 30 min post-exercise. An ultradian pattern of Peptide F distribution was apparent during rest. Furthermore, concentrations of T cells, B cells, NK cells, and total WBCs demonstrated significant changes in response to aerobic exercise. Data indicated that Peptide F was bound in significant molar concentrations in the WBC fraction and that this biocompartment may be one of the tissue targets for binding interactions. These data indicate that Peptide F is involved with immune cell modulation in the white blood circulatory biocompartment of blood. Copyright © 2013. Published by Elsevier Inc.

Is the β phase maximal?

International Nuclear Information System (INIS)

Ferrandis, Javier

2005-01-01

The current experimental determination of the absolute values of the CKM elements indicates that 2 vertical bar V ub /V cb V us vertical bar =(1-z), with z given by z=0.19+/-0.14. This fact implies that irrespective of the form of the quark Yukawa matrices, the measured value of the SM CP phase β is approximately the maximum allowed by the measured absolute values of the CKM elements. This is β=(π/6-z/3) for γ=(π/3+z/3), which implies α=π/2. Alternatively, assuming that β is exactly maximal and using the experimental measurement sin(2β)=0.726+/-0.037, the phase γ is predicted to be γ=(π/2-β)=66.3 o +/-1.7 o . The maximality of β, if confirmed by near-future experiments, may give us some clues as to the origin of CP violation

TRAINING-INDUCED CHANGES IN THE TOPOGRAPHY OF MUSCLE TORQUES AND MAXIMAL MUSCLE TORQUES IN BASKETBALL PLAYERS

Directory of Open Access Journals (Sweden)

Krzysztof Buśko

2012-01-01

Full Text Available The aim of the study was to detect changes in the maximal muscle torques in male basketball players during a two-year training cycle. We verified the hypothesis that different workloads applied during the preparation and competition periods would result in changes in the maximal muscle torques of the athletes (increase during the former and decrease or no change during the latter period accompanied by no alteration of the percent muscle topography of all the muscle groups tested. The examinations were conducted on nine senior male basketball players from the Polish national team. Estimations of the muscle torques in static conditions were performed at the end of the preparation (measurements I and III and competition (measurements II and IV periods of a two-year training cycle. Eleven muscle groups were studied including flexors and extensors of the trunk and flexors and extensors of the shoulder, the elbow, the hip, the knee, and the ankle. Muscle torques of the shoulder and the elbow insignificantly decreased except for the muscle torque of the flexors of the shoulder. Muscle torques of the flexors and extensors of the trunk as well as of the flexors and extensors of the hip, the knee, and the ankle increased between measurements I and III and between measurements I and IV with the only exception being the muscle torque of the flexors of the knee (which significantly decreased by 7.4% In the case of the flexors and extensors of the trunk and the flexors and extensors of the hip, the changes appeared to be significant. The sum of the muscle torques of the upper limbs markedly decreased between the preparation (measurement I and competition (measurement IV periods. The sum of the muscle torques of the trunk and the lower limbs and the sum of the muscle torques of the eleven muscle groups significantly increased between measurements I and IV. Percent muscle topography significantly decreased for the flexors and extensors of the shoulder and the

Quantum speedup in solving the maximal-clique problem

Science.gov (United States)

Chang, Weng-Long; Yu, Qi; Li, Zhaokai; Chen, Jiahui; Peng, Xinhua; Feng, Mang

2018-03-01

The maximal-clique problem, to find the maximally sized clique in a given graph, is classically an NP-complete computational problem, which has potential applications ranging from electrical engineering, computational chemistry, and bioinformatics to social networks. Here we develop a quantum algorithm to solve the maximal-clique problem for any graph G with n vertices with quadratic speedup over its classical counterparts, where the time and spatial complexities are reduced to, respectively, O (√{2n}) and O (n2) . With respect to oracle-related quantum algorithms for the NP-complete problems, we identify our algorithm as optimal. To justify the feasibility of the proposed quantum algorithm, we successfully solve a typical clique problem for a graph G with two vertices and one edge by carrying out a nuclear magnetic resonance experiment involving four qubits.

Muscle mitochondrial capacity exceeds maximal oxygen delivery in humans

DEFF Research Database (Denmark)

Boushel, Robert Christopher; Gnaiger, Erich; Calbet, Jose A L

2011-01-01

Across a wide range of species and body mass a close matching exists between maximal conductive oxygen delivery and mitochondrial respiratory rate. In this study we investigated in humans how closely in-vivo maximal oxygen consumption (VO(2) max) is matched to state 3 muscle mitochondrial respira...

Petroleum industry is cleaning up its act -- Self-cleaning filters to maximize profits, minimize waste and reduce liability

International Nuclear Information System (INIS)

Williams, D.

2004-01-01

Recent steps taken by the petroleum industry to control end-of-pipe pollution and to minimize waste at the source by changing over to self-cleaning, backwashable filters instead of the traditional disposable filters such as bags or cartridges, are discussed. Various self-cleaning filter systems and their advantages are described, using REACTOGARD which provides total protection for catalysts in fixed-bed reactors and EROSIONGARD, used in fluidized catalytic crackers, as examples. Both filter systems have been developed by RPA Process Technologies, Inc., a global leader in industrial filtration systems. Major advantages attributed to self-cleaning filters include significantly reduced costs through reducing the number of catalyst change-out cycles, maximized platform productivity through virtually eliminating the risk of plugged wells, reduced waste through ability to recycle cleaning liquids, increased profits through shorter return-on-investment cycles, reduced emissions and reduced future liability through higher safety in the workplace; also reduced pollution of landfill sites. 1 photo

The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint.

Science.gov (United States)

Phillips, Shaun M; Findlay, Scott; Kavaliauskas, Mykolas; Grant, Marie Clare

2014-05-01

The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO) mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD) age: 23.1 (3.0) years, height: 1.83 (0.07) m, body mass (BM): 86.3 (13.5) kg) completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin) solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA) solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg(-1) BM resistance. Eight participants achieved a greater peak power output (PPO) in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg(-1), p 0.05). No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint. Key pointsThe paper demonstrates that repeated administration of a carbohydrate mouth rinse can significantly improve peak power output during a single 30 second cycle sprint.The ergogenic effect of the carbohydrate mouth rinse may relate to the duration of exposure of the oral cavity to the mouth rinse, and associated greater stimulation of oral carbohydrate receptors.The significant increase in peak power output with the carbohydrate mouth rinse may come at a relative cost for the remainder of the sprint, evidenced by non-significantly lower mean power output and a greater fatigue index in the carbohydrate vs. placebo trial.Serial administration of a carbohydrate mouth rinse may be beneficial for

Exercise performance and differences in physiological response to pulmonary rehabilitation in severe chronic obstructive pulmonary disease with hyperinflation

Directory of Open Access Journals (Sweden)

André Luis Pereira de Albuquerque

2016-04-01

Full Text Available Objective: Pulmonary rehabilitation (PR improves exercise capacity in most but not all COPD patients. The factors associated with treatment success and the role of chest wall mechanics remain unclear. We investigated the impact of PR on exercise performance in COPD with severe hyperinflation. Methods: We evaluated 22 COPD patients (age, 66 ± 7 years; FEV1 = 37.1 ± 11.8% of predicted who underwent eight weeks of aerobic exercise and strength training. Before and after PR, each patient also performed a six-minute walk test and an incremental cycle ergometer test. During the latter, we measured chest wall volumes (total and compartmental, by optoelectronic plethysmography and determined maximal workloads. Results: We observed significant differences between the pre- and post-PR means for six-minute walk distance (305 ± 78 vs. 330 ± 96 m, p < 0.001 and maximal workload (33 ± 21 vs. 39 ± 20 W; p = 0.02. At equivalent workload settings, PR led to lower oxygen consumption, carbon dioxide production (VCO2, and minute ventilation. The inspiratory (operating rib cage volume decreased significantly after PR. There were 6 patients in whom PR did not increase the maximal workload. After PR, those patients showed no significant decrease in VCO2 during exercise, had higher end-expiratory chest wall volumes with a more rapid shallow breathing pattern, and continued to experience symptomatic leg fatigue. Conclusions: In severe COPD, PR appears to improve oxygen consumption and reduce VCO2, with a commensurate decrease in respiratory drive, changes reflected in the operating chest wall volumes. Patients with severe post-exercise hyperinflation and leg fatigue might be unable to improve their maximal performance despite completing a PR program.

Effects of different modes of exercise on appetite and appetite-regulating hormones.

Science.gov (United States)

Kawano, Hiroshi; Mineta, Mayuko; Asaka, Meiko; Miyashita, Masashi; Numao, Shigeharu; Gando, Yuko; Ando, Takafumi; Sakamoto, Shizuo; Higuchi, Mitsuru

2013-07-01

The present study determined the changes in appetite and appetite-regulating gut hormones during and following bouts of both rope skipping exercise (weight-bearing) and bicycle ergometer exercise (non-weight-bearing). After a 12-h fast, 15 young men (mean ± SD, age 24.4 ± 1.7 yrs, maximal oxygen uptake 47.0 ± 6.5 mL/kg/min) participated in three 160 min trials: (1) rope skipping exercise (295 ± 40 kcal, 3 sets × 10 min with 5-min interval, then rested for 120 min); (2) bicycle ergometer exercise (288 ± 36 kcal, 3 sets × 10 min with 5-min interval, then rested for 120 min); (3) control (rested for 160 min). Ratings of perceived hunger and acylated ghrelin were suppressed and total peptide YY (PYY) were increased during and immediately after exercise in both exercise trials, but glucagon liked peptide-1 was not changed. Furthermore, suppressed hunger during rope skipping exercise was greater than that during bicycle ergometer exercise, but there were no differences in acylated ghrelin and total PYY. These results indicate that weight-bearing exercise has a greater exercise-induced appetite suppressive effect compared with non-weight-bearing exercise, and both forms of exercise lowered acylated ghrelin and increased total PYY, but the changes did not differ significantly between exercise modes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enumerating all maximal frequent subtrees in collections of phylogenetic trees.

Science.gov (United States)

Deepak, Akshay; Fernández-Baca, David

2014-01-01

A common problem in phylogenetic analysis is to identify frequent patterns in a collection of phylogenetic trees. The goal is, roughly, to find a subset of the species (taxa) on which all or some significant subset of the trees agree. One popular method to do so is through maximum agreement subtrees (MASTs). MASTs are also used, among other things, as a metric for comparing phylogenetic trees, computing congruence indices and to identify horizontal gene transfer events. We give algorithms and experimental results for two approaches to identify common patterns in a collection of phylogenetic trees, one based on agreement subtrees, called maximal agreement subtrees, the other on frequent subtrees, called maximal frequent subtrees. These approaches can return subtrees on larger sets of taxa than MASTs, and can reveal new common phylogenetic relationships not present in either MASTs or the majority rule tree (a popular consensus method). Our current implementation is available on the web at https://code.google.com/p/mfst-miner/. Our computational results confirm that maximal agreement subtrees and all maximal frequent subtrees can reveal a more complete phylogenetic picture of the common patterns in collections of phylogenetic trees than maximum agreement subtrees; they are also often more resolved than the majority rule tree. Further, our experiments show that enumerating maximal frequent subtrees is considerably more practical than enumerating ordinary (not necessarily maximal) frequent subtrees.

Softly Broken Lepton Numbers: an Approach to Maximal Neutrino Mixing

International Nuclear Information System (INIS)

Grimus, W.; Lavoura, L.

2001-01-01

We discuss models where the U(1) symmetries of lepton numbers are responsible for maximal neutrino mixing. We pay particular attention to an extension of the Standard Model (SM) with three right-handed neutrino singlets in which we require that the three lepton numbers L e , L μ , and L τ be separately conserved in the Yukawa couplings, but assume that they are softly broken by the Majorana mass matrix M R of the neutrino singlets. In this framework, where lepton-number breaking occurs at a scale much higher than the electroweak scale, deviations from family lepton number conservation are calculable, i.e., finite, and lepton mixing stems exclusively from M R . We show that in this framework either maximal atmospheric neutrino mixing or maximal solar neutrino mixing or both can be imposed by invoking symmetries. In this way those maximal mixings are stable against radiative corrections. The model which achieves maximal (or nearly maximal) solar neutrino mixing assumes that there are two different scales in M R and that the lepton number (dash)L=L e -L μ -L τ 1 is conserved in between them. We work out the difference between this model and the conventional scenario where (approximate) (dash)L invariance is imposed directly on the mass matrix of the light neutrinos. (author)

Power Converters Maximize Outputs Of Solar Cell Strings

Science.gov (United States)

Frederick, Martin E.; Jermakian, Joel B.

1993-01-01

Microprocessor-controlled dc-to-dc power converters devised to maximize power transferred from solar photovoltaic strings to storage batteries and other electrical loads. Converters help in utilizing large solar photovoltaic arrays most effectively with respect to cost, size, and weight. Main points of invention are: single controller used to control and optimize any number of "dumb" tracker units and strings independently; power maximized out of converters; and controller in system is microprocessor.

No Mikheyev-Smirnov-Wolfenstein Effect in Maximal Mixing

OpenAIRE

Harrison, P. F.; Perkins, D. H.; Scott, W. G.

1996-01-01

We investigate the possible influence of the MSW effect on the expectations for the solar neutrino experiments in the maximal mixing scenario suggested by the atmospheric neutrino data. A direct numerical calculation of matter induced effects in the Sun shows that the naive vacuum predictions are left completely undisturbed in the particular case of maximal mixing, so that the MSW effect turns out to be unobservable. We give a qualitative explanation of this result.

Mathematical model of the reformer sponge iron cycle

Energy Technology Data Exchange (ETDEWEB)

Fraser, S.; Hacker, V.; Evers, B.; Hierzer, J.; Besenhard, J.O. [Graz University of Technology, Graz (Austria). Inst. for Chemical Technology of Inorganic Materials Christian Doppler Pilot-Lab. for Fuel Cell Systems

2003-07-01

An innovative hydrogen production process called the Reformer Sponge Iron Cycle (RESC), based on redox reactions of iron ore pellets, was mathematically modeled. The hydrogen is produced by blowing steam over hot iron pellets in the oxidation stage, resulting in the oxidation of the iron. Synthesis gas coming from a reformer mixed with a fraction of recycled off-gas was used to reduce the iron oxide pellets (wuestite and-or magnetite) in the reduction stage, leading once more to iron . Once the mathematical model was developed, it was verified utilizing experimental data. Based on calculations of the equilibrium gas concentrations for reformer and sponge iron reactor (SIR), the model computes mass fluxes, molar fluxes, partial pressures, and variations of them throughout the complete cycle. The recycle rate, which determines the fraction of SIR off-gas recycled and added to the input gas stream, was optimized to maximize the amount of iron oxide reduced for a certain input gas flow. 5 refs., 4 figs.

Primary granulocyte colony-stimulating factor prophylaxis during the first two cycles only or throughout all chemotherapy cycles in patients with breast cancer at risk for febrile neutropenia.

Science.gov (United States)

Aarts, Maureen J; Peters, Frank P; Mandigers, Caroline M; Dercksen, M Wouter; Stouthard, Jacqueline M; Nortier, Hans J; van Laarhoven, Hanneke W; van Warmerdam, Laurence J; van de Wouw, Agnes J; Jacobs, Esther M; Mattijssen, Vera; van der Rijt, Carin C; Smilde, Tineke J; van der Velden, Annette W; Temizkan, Mehmet; Batman, Erdogan; Muller, Erik W; van Gastel, Saskia M; Borm, George F; Tjan-Heijnen, Vivianne C G

2013-12-01

Early breast cancer is commonly treated with anthracyclines and taxanes. However, combining these drugs increases the risk of myelotoxicity and may require granulocyte colony-stimulating factor (G-CSF) support. The highest incidence of febrile neutropenia (FN) and largest benefit of G-CSF during the first cycles of chemotherapy lead to questions about the effectiveness of continued use of G-CSF throughout later cycles of chemotherapy. In a multicenter study, patients with breast cancer who were considered fit enough to receive 3-weekly polychemotherapy, but also had > 20% risk for FN, were randomly assigned to primary G-CSF prophylaxis during the first two chemotherapy cycles only (experimental arm) or to primary G-CSF prophylaxis throughout all chemotherapy cycles (standard arm). The noninferiority hypothesis was that the incidence of FN would be maximally 7.5% higher in the experimental compared with the standard arm. After inclusion of 167 eligible patients, the independent data monitoring committee advised premature study closure. Of 84 patients randomly assigned to G-CSF throughout all chemotherapy cycles, eight (10%) experienced an episode of FN. In contrast, of 83 patients randomly assigned to G-CSF during the first two cycles only, 30 (36%) had an FN episode (95% CI, 0.13 to 0.54), with a peak incidence of 24% in the third cycle (ie, first cycle without G-CSF prophylaxis). In patients with early breast cancer at high risk for FN, continued use of primary G-CSF prophylaxis during all chemotherapy cycles is of clinical relevance and thus cannot be abandoned.

Single maximal versus combination punch kinematics.

Science.gov (United States)

Piorkowski, Barry A; Lees, Adrian; Barton, Gabor J

2011-03-01

The aim of this study was to determine the influence of punch type (Jab, Cross, Lead Hook and Reverse Hook) and punch modality (Single maximal, 'In-synch' and 'Out of synch' combination) on punch speed and delivery time. Ten competition-standard volunteers performed punches with markers placed on their anatomical landmarks for 3D motion capture with an eight-camera optoelectronic system. Speed and duration between key moments were computed. There were significant differences in contact speed between punch types (F(2,18,84.87) = 105.76, p = 0.001) with Lead and Reverse Hooks developing greater speed than Jab and Cross. There were significant differences in contact speed between punch modalities (F(2,64,102.87) = 23.52, p = 0.001) with the Single maximal (M+/- SD: 9.26 +/- 2.09 m/s) higher than 'Out of synch' (7.49 +/- 2.32 m/s), 'In-synch' left (8.01 +/- 2.35 m/s) or right lead (7.97 +/- 2.53 m/s). Delivery times were significantly lower for Jab and Cross than Hook. Times were significantly lower 'In-synch' than a Single maximal or 'Out of synch' combination mode. It is concluded that a defender may have more evasion-time than previously reported. This research could be of use to performers and coaches when considering training preparations.

Formation Control for the MAXIM Mission

Science.gov (United States)

Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

2004-01-01

Over the next twenty years, a wave of change is occurring in the space-based scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today s technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. MAXIM formation flying requirements are on the order of microns, while Stellar Imager mission requirements are on the order of nanometers. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; and (2) the development of linearized equations of relative motion for a formation operating in an n-body gravitational field. Linearized equations of motion provide the ground work for linear formation control designs.

Conversational Implicature of Peanuts Comic Strip Based on Grice’s Maxim Theory

Directory of Open Access Journals (Sweden)

Muhartoyo Muhartoyo

2013-04-01

Full Text Available This article discusses about conversational implicature that occurs in Peanuts comic strips. The objectives of this study are to find out the implied meaning in the conversation between Charlie Brown with Lucy van Pelt and Lucy van Pelt with Linus van Pelt to evaluate the existence of maxim flouting and maxim violating in those conversations in relation to the four maxims such as quantity, quality, relation, and manner. Likewise, this study attempts to find out the reason for using conversational implicature in a comic strip. The writers uses a qualitative method with library research concerning to Grice’s maxim theory to analyze the conversational implicature. Based on the analysis, it can be concluded that all the comics that comprise 14 comics generate conversational implicature since all the characters breach rules of maxim. The result of this analysis shows that flouting maxim of manner has the highest occurrence of conversational implicature and the least occurrences belong to flouting maxim of relation and violating maxim of quantity. Moreover, the writers concludes that to make a successful communication ideally the speaker and the hearer to cooperate in the conversation by saying explicitly so the hearer can grasp the meaning as the goal of communication is to deliver a message to the hearer.  

Comparison of changes in the mobility of the pelvic floor muscle on during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction.

Science.gov (United States)

Jung, Halim; Jung, Sangwoo; Joo, Sunghee; Song, Changho

2016-01-01

[Purpose] The purpose of this study was to compare changes in the mobility of the pelvic floor muscle during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction. [Subjects] Thirty healthy adults participated in this study (15 men and 15 women). [Methods] All participants performed a bridge exercise and abdominal curl-up during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction. Pelvic floor mobility was evaluated as the distance from the bladder base using ultrasound. [Results] According to exercise method, bridge exercise and abdominal curl-ups led to significantly different pelvic floor mobility. The pelvic floor muscle was elevated during the abdominal drawing-in maneuver and descended during maximal expiration. Finally, pelvic floor muscle mobility was greater during abdominal curl-up than during the bridge exercise. [Conclusion] According to these results, the abdominal drawing-in maneuver induced pelvic floor muscle contraction, and pelvic floor muscle contraction was greater during the abdominal curl-up than during the bridge exercise.

Descriptive Analysis on Flouting and Hedging of Conversational Maxims in the “Post Grad” Movie

Directory of Open Access Journals (Sweden)

Nastiti Rokhmania

2012-11-01

Full Text Available This research is focused on analyzing flouting and hedging of conversational maxim of utterances used by the main characters in “Post Grad” movie. Conversational maxims are the rules of cooperative principle categorized into four categories; Maxim of Quality, Maxim of Quantity, Maxim of Relevance, and Maxim of Manner. If these maxims are used in conversations, the conversations can go smoothly. However, people often break the maxims overtly (flouting maxim and sometimes break the maxims secretly (hedging maxims when they make a conversation. This research is conducted using descriptive qualitative method based on the theory known as Grice’s Maxims. The data are in form of utterances used by the characters in “Post Grad” movie. The data analysis reveals some finding covering the formulated research question. The maxims are flouted when the speaker breaks some conversational maxims when using the utterances in the form of rhetorical strategies, such as tautology, metaphor, hyperbole, irony, and rhetorical question. On the other hand, conversational maxims are also hedged when the information is not totally accurate or unclearly stated but seems informative, well-founded, and relevant.

EFFECT OF THE ROTOR CRANK SYSTEM ON CYCLING PERFORMANCE

Directory of Open Access Journals (Sweden)

Simon A. Jobson

2009-09-01

Full Text Available The aim of this study was to evaluate the impact of a novel crank system on laboratory time-trial cycling performance. The Rotor system makes each pedal independent from the other so that the cranks are no longer fixed at 180°. Twelve male competitive but non-elite cyclists (mean ± s: 35 ± 7 yr, Wmax = 363 ± 38 W, VO2peak = 4.5 ± 0.3 L·min-1 completed 6-weeks of their normal training using either a conventional (CON or the novel Rotor (ROT pedal system. All participants then completed two 40.23-km time-trials on an air-braked ergometer, one using CON and one using ROT. Mean performance speeds were not different between trials (CON = 41.7 km·h-1 vs. ROT = 41.6 km·h-1, P > 0.05. Indeed, the pedal system used during the time-trials had no impact on any of the measured variables (power output, cadence, heart rate, VO2, RER, gross efficiency. Furthermore, the ANOVA identified no significant interaction effect between main effects (Time-trial crank system*Training crank system, P > 0.05. To the authors' knowledge, this is the first study to examine the effects of the Rotor system on endurance performance rather than endurance capacity. These results suggest that the Rotor system has no measurable impact on time-trial performance. However, further studies should examine the importance of the Rotor 'regulation point' and the suggestion that the Rotor system has acute ergogenic effects if used infrequently

A Conceptual Study of Using an Isothermal Compressor on a Supercritical CO{sub 2} Brayton Cycle for SMART Application

Energy Technology Data Exchange (ETDEWEB)

Heo, Jin Young; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Ahn, Yoonhan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

To maximize the benefits of modularization, the supercritical CO{sub 2} (S-CO{sub 2}) power cycle can replace the conventional steam Rankine cycle to increase the cycle efficiency and reduce its system size. Previous works have been conducted to evaluate potential advantages of applying the S-CO{sub 2} cycle to SMRs, specifically to SMART (System-integrated Modular Advanced Reactor) which is an integral SMR developed by KAERI (Korea Atomic Energy Institute). One of the optimized S-CO{sub 2} cycle layouts is the recompressing Brayton cycle. This paper attempts to improve the cycle layout by replacing the conventional compressor with an isothermal compressor, of which its potential in the S-CO{sub 2} power cycle is conceptually being evaluated. The SMR applications, for which SMART reactor has been represented, can take advantage of the currently developing S-CO{sub 2} cycle greatly by the reduction of size. By introducing the isothermal compressor, the cycle layout considered in has been further improved by increasing the cycle net efficiency by around 0.5%.

Characterisation of cell cycle arrest and terminal differentiation in a maximally proliferative human epithelial tissue: Lessons from the human hair follicle matrix.

Science.gov (United States)

Purba, Talveen S; Brunken, Lars; Peake, Michael; Shahmalak, Asim; Chaves, Asuncion; Poblet, Enrique; Ceballos, Laura; Gandarillas, Alberto; Paus, Ralf

2017-09-01

Human hair follicle (HF) growth and hair shaft formation require terminal differentiation-associated cell cycle arrest of highly proliferative matrix keratinocytes. However, the regulation of this complex event remains unknown. CIP/KIP family member proteins (p21 CIP1 , p27 KIP1 and p57 KIP2 ) regulate cell cycle progression/arrest, endoreplication, differentiation and apoptosis. Since they have not yet been adequately characterized in the human HF, we asked whether and where CIP/KIP proteins localise in the human hair matrix and pre-cortex in relation to cell cycle activity and HF-specific epithelial cell differentiation that is marked by keratin 85 (K85) protein expression. K85 expression coincided with loss or reduction in cell cycle activity markers, including in situ DNA synthesis (EdU incorporation), Ki-67, phospho-histone H3 and cyclins A and B1, affirming a post-mitotic state of pre-cortical HF keratinocytes. Expression of CIP/KIP proteins was found abundantly within the proliferative hair matrix, concomitant with a role in cell cycle checkpoint control. p21 CIP1 , p27 KIP1 and cyclin E persisted within post-mitotic keratinocytes of the pre-cortex, whereas p57 KIP2 protein decreased but became nuclear. These data imply a supportive role for CIP/KIP proteins in maintaining proliferative arrest, differentiation and anti-apoptotic pathways, promoting continuous hair bulb growth and hair shaft formation in anagen VI. Moreover, post-mitotic hair matrix regions contained cells with enlarged nuclei, and DNA in situ hybridisation showed cells that were >2N in the pre-cortex. This suggests that CIP/KIP proteins might counterbalance cyclin E to control further rounds of DNA replication in a cell population that has a propensity to become tetraploid. These data shed new light on the in situ-biography of human hair matrix keratinocytes on their path of active cell cycling, arrest and terminal differentiation, and showcase the human HF as an excellent, clinically

Maximal and anaerobic threshold cardiorespiratory responses during deepwater running

Directory of Open Access Journals (Sweden)

Ana Carolina Kanitz

2014-12-01

Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2015v17n1p41   Aquatic exercises provide numerous benefits to the health of their practitioners. To secure these benefits, it is essential to have proper prescriptions to the needs of each individual and, therefore, it is important to study the cardiorespiratory responses of different activities in this environment. Thus, the aim of this study was to compare the cardiorespiratory responses at the anaerobic threshold (AT between maximal deep-water running (DWR and maximal treadmill running (TMR. In addition, two methods of determining the AT (the heart rate deflection point [HRDP] and ventilatory method [VM] are compared in the two evaluated protocols. Twelve young women performed the two maximal protocols. Two-factor ANOVA for repeated measures with a post-hoc Bonferroni test was used (α < 0.05. Significantly higher values of maximal heart rate (TMR: 33.7 ± 3.9; DWR: 22.5 ± 4.1 ml.kg−1.min−1 and maximal oxygen uptake (TMR: 33.7 ± 3.9; DWR: 22.5 ± 4.1 ml.kg−1.min−1 in TMR compared to the DWR were found. Furthermore, no significant differences were found between the methods for determining the AT (TMR: VM: 28.1 ± 5.3, HRDP: 26.6 ± 5.5 ml.kg−1.min−1; DWR: VM: 18.7 ± 4.8, HRDP: 17.8 ± 4.8 ml.kg−1.min−1. The results indicate that a specific maximal test for the trained modality should be conducted and the HRDP can be used as a simple and practical method of determining the AT, based on which the training intensity can be determined

Operating cycle optimization for a Magnus effect-based airborne wind energy system

International Nuclear Information System (INIS)

Milutinović, Milan; Čorić, Mirko; Deur, Joško

2015-01-01

Highlights: • Operating cycle of a Magnus effect-based AWE system has been optimized. • The cycle trajectory should be vertical and far from the ground based generator. • Vertical trajectory provides high pulling force that drives the generator. • Large distance from the generator is required for the feasibility of the cycle. - Abstract: The paper presents a control variables optimization study for an airborne wind energy production system. The system comprises an airborne module in the form of a buoyant, rotating cylinder, whose rotation in a wind stream induces the Magnus effect-based aerodynamic lift. Through a tether, the airborne module first drives the generator fixed on the ground, and then the generator becomes a motor that lowers the airborne module. The optimization is aimed at maximizing the average power produced at the generator during a continuously repeatable operating cycle. The control variables are the generator-side rope force and the cylinder rotation speed. The optimization is based on a multi-phase problem formulation, where operation is divided into ascending and descending phases, with free boundary conditions and free cycle duration. The presented simulation results show that significant power increase can be achieved by using the obtained optimal operating cycle instead of the initial, empirically based operation control strategy. A brief analysis is also given to provide a physical interpretation of the optimal cycle results

Energy Expenditure Evaluation in Humans and Non-Human Primates by SenseWear Armband. Validation of Energy Expenditure Evaluation by SenseWear Armband by Direct Comparison with Indirect Calorimetry

Science.gov (United States)

Casiraghi, Francesca; Chavez, Alberto O.; Davalli, Alberto M.; Naegelin, Terry; Comuzzie, Anthony G.; Frost, Patricia; Musi, Nicolas; Folli, Franco

2013-01-01

Introduction The purpose of this study was to compare and validate the use of SenseWear Armband (SWA) placed on the arm (SWA ARM) and on the back (SWA BACK) in healthy humans during resting and a cycle-ergometer exercise and to evaluate the SWA to estimate Resting Energy Expenditure (REE) and Total Energy Expenditure (TEE) in healthy baboons. Methods We studied 26 (15F/11M) human subjects wearing SWA in two different anatomical sites (arm and back) during resting and a cycle-ergometer test and directly compared these results with indirect calorimetry evaluation (IC), performed at the same time. We then inserted the SWA in a metabolic jacket for baboons and evaluated the TEE and REE in free living condition for 6 days in 21 (8F/13M) non-human primates. Results In humans we found a good correlation between SWA place on the ARM and on the BACK with IC during the resting experiment (1.1±0.3 SWAs, 1±0.2 IC kcal/min) and a slight underestimation in the SWAs data compared with IC during the cycle-ergometer exercise (5±1.9 SWA ARM, 4.5±1.5 SWA BACK and 5.4±2.1 IC kcal/min). In the non-human primate (baboons) experiment SWA estimated a TEE of 0.54±0.009 kcal/min during free living and a REE of 0.82±0.06 kcal/min. Conclusion SWA, an extremely simple and inexpensive apparatus, provides quite accurate measurements of energy expenditure in humans and in baboons. Energy expenditure data obtained with SWA are highly correlated with the data obtained with “gold standard”, IC, in humans. PMID:24069218

Quantization with maximally degenerate Poisson brackets: the harmonic oscillator!

International Nuclear Information System (INIS)

Nutku, Yavuz

2003-01-01

Nambu's construction of multi-linear brackets for super-integrable systems can be thought of as degenerate Poisson brackets with a maximal set of Casimirs in their kernel. By introducing privileged coordinates in phase space these degenerate Poisson brackets are brought to the form of Heisenberg's equations. We propose a definition for constructing quantum operators for classical functions, which enables us to turn the maximally degenerate Poisson brackets into operators. They pose a set of eigenvalue problems for a new state vector. The requirement of the single-valuedness of this eigenfunction leads to quantization. The example of the harmonic oscillator is used to illustrate this general procedure for quantizing a class of maximally super-integrable systems

Maximally flat radiation patterns of a circular aperture

Science.gov (United States)

Minkovich, B. M.; Mints, M. Ia.

1989-08-01

The paper presents an explicit solution to the problems of maximizing the area utilization coefficient and of obtaining the best approximation (on the average) of a sectorial Pi-shaped radiation pattern of an antenna with a circular aperture when Butterworth conditions are imposed on the approximating pattern with the aim of flattening it. Constraints on the choice of admissible minimum and maximum antenna dimensions are determined which make possible the synthesis of maximally flat patterns with small sidelobes.

On Maximally Dissipative Shock Waves in Nonlinear Elasticity

OpenAIRE

Knowles, James K.

2010-01-01

Shock waves in nonlinearly elastic solids are, in general, dissipative. We study the following question: among all plane shock waves that can propagate with a given speed in a given one-dimensional nonlinearly elastic bar, which one—if any—maximizes the rate of dissipation? We find that the answer to this question depends strongly on the qualitative nature of the stress-strain relation characteristic of the given material. When maximally dissipative shocks do occur, they propagate according t...

The Large Margin Mechanism for Differentially Private Maximization

OpenAIRE

Chaudhuri, Kamalika; Hsu, Daniel; Song, Shuang

2014-01-01

A basic problem in the design of privacy-preserving algorithms is the private maximization problem: the goal is to pick an item from a universe that (approximately) maximizes a data-dependent function, all under the constraint of differential privacy. This problem has been used as a sub-routine in many privacy-preserving algorithms for statistics and machine-learning. Previous algorithms for this problem are either range-dependent---i.e., their utility diminishes with the size of the universe...

Enumerating all maximal frequent subtrees in collections of phylogenetic trees

Science.gov (United States)

2014-01-01

Background A common problem in phylogenetic analysis is to identify frequent patterns in a collection of phylogenetic trees. The goal is, roughly, to find a subset of the species (taxa) on which all or some significant subset of the trees agree. One popular method to do so is through maximum agreement subtrees (MASTs). MASTs are also used, among other things, as a metric for comparing phylogenetic trees, computing congruence indices and to identify horizontal gene transfer events. Results We give algorithms and experimental results for two approaches to identify common patterns in a collection of phylogenetic trees, one based on agreement subtrees, called maximal agreement subtrees, the other on frequent subtrees, called maximal frequent subtrees. These approaches can return subtrees on larger sets of taxa than MASTs, and can reveal new common phylogenetic relationships not present in either MASTs or the majority rule tree (a popular consensus method). Our current implementation is available on the web at https://code.google.com/p/mfst-miner/. Conclusions Our computational results confirm that maximal agreement subtrees and all maximal frequent subtrees can reveal a more complete phylogenetic picture of the common patterns in collections of phylogenetic trees than maximum agreement subtrees; they are also often more resolved than the majority rule tree. Further, our experiments show that enumerating maximal frequent subtrees is considerably more practical than enumerating ordinary (not necessarily maximal) frequent subtrees. PMID:25061474

Pace's Maxims for Homegrown Library Projects. Coming Full Circle

Science.gov (United States)

Pace, Andrew K.

2005-01-01

This article discusses six maxims by which to run library automation. The following maxims are discussed: (1) Solve only known problems; (2) Avoid changing data to fix display problems; (3) Aut viam inveniam aut faciam; (4) If you cannot make it yourself, buy something; (5) Kill the alligator closest to the boat; and (6) Just because yours is…

Alkaloids from Juglans Mandshurica maxim induce distinctive cell death in hepatocellular carcinoma cells.

Science.gov (United States)

Lou, Li-Li; Cheng, Zhuo-Yang; Guo, Rui; Yao, Guo-Dong; Song, Shao-Jiang

2017-12-15

The aim of this work was to further investigate the anticancer potential of Juglans mandshurica Maxim, including the separation of active constituents and their anti-proliferative effects with underlying mechanism of action. Five alkaloids (1-5) were isolated from the bark of J. mandshurica. Among them, 1 showed the highest cytotoxic activities against Hep3B and HepG2 cells with an IC50 values of 61.80 and 56.24 μM, respectively. Therefore, the cellular mechanism involved 1 was subsequently studied. Our results showed that 1 markedly caused apoptosis and autophagy, but without cell cycle arrest in HepG2 cells. Interestingly, only autophagic cell death was induced in 1-treated Hep3B cells. It is concluded that the isolated alkaloids exerted a certain anti-hepatoma potential, and our results may provide a basis for the further investigation of the alkaloids extracted from J. mandshurica.

Gravitational collapse of charged dust shell and maximal slicing condition

International Nuclear Information System (INIS)

Maeda, Keiichi

1980-01-01

The maximal slicing condition is a good time coordinate condition qualitatively when pursuing the gravitational collapse by the numerical calculation. The analytic solution of the gravitational collapse under the maximal slicing condition is given in the case of a spherical charged dust shell and the behavior of time slices with this coordinate condition is investigated. It is concluded that under the maximal slicing condition we can pursue the gravitational collapse until the radius of the shell decreases to about 0.7 x (the radius of the event horizon). (author)

A definition of maximal CP-violation

International Nuclear Information System (INIS)

Roos, M.

1985-01-01

The unitary matrix of quark flavour mixing is parametrized in a general way, permitting a mathematically natural definition of maximal CP violation. Present data turn out to violate this definition by 2-3 standard deviations. (orig.)

Impact of sodium citrate ingestion during recovery after dehydrating exercise on rehydration and subsequent 40-km cycling time-trial performance in the heat.

Science.gov (United States)

Suvi, Silva; Mooses, Martin; Timpmann, Saima; Medijainen, Luule; Narõškina, Daria; Unt, Eve; Ööpik, Vahur

2018-01-11

The purpose of this study was to assess the impact of sodium citrate (CIT) ingestion (600 mg·kg -1 ) during recovery from dehydrating cycling exercise (DE) on subsequent 40-km cycling performance in a warm environment (32 °C). Twenty male nonheat-acclimated endurance athletes exercised in the heat until 4% body mass (BM) loss occurred. After 16 h recovery with consumption of water ad libitum and prescribed diet (evening meal 20 kcal·kg -1 , breakfast 12 kcal·kg -1 ) supplemented in a double-blind, randomized, crossover manner with CIT or placebo (PLC), they performed 40-km time-trial (TT) on a cycle ergometer in a warm environment. During recovery greater increases in BM and plasma volume (PV) concomitant with greater water intake and retention occurred in the CIT trial compared with the PLC trial (p 0.05) in sweat loss, PV decrement, ratings of perceived exertion, or TT time (CIT 68.10 ± 3.28 min, PLC 68.11 ± 2.87 min). At the end of TT blood lactate concentration was higher (7.58 ± 2.44 mmol·L -1 vs 5.58 ± 1.32 mmol·L -1 ; p = 0.0002) and rectal temperature lower (39.54 ± 0.50 °C vs 39.65 ± 0.52 °C; p = 0.033) in the CIT trial than in the PLC trial. Compared with pre-DE time point, PV had decreased to a lower level in the PLC trial than in the CIT trial (p = 0.0001). In conclusion, CIT enhances rehydration after exercise-induced dehydration but has no impact on subsequent 40-km cycling TT performance in a warm uncompensable environment.

Deconstructing facts and frames in energy research: Maxims for evaluating contentious problems

International Nuclear Information System (INIS)

Sovacool, Benjamin K.; Brown, Marilyn A.

2015-01-01

In this article, we argue that assumptions and values can play a combative, corrosive role in the generation of objective energy analysis. We then propose six maxims for energy analysts and researchers. Our maxim of information asks readers to keep up to date on trends in energy resources and technology. Our maxim of inclusivity asks readers to involve citizens and other public actors more in energy decisions. Our maxim of symmetry asks readers to keep their analysis of energy technologies centered always on both technology and society. Our maxim of reflexivity asks readers to be self-aware of one's assumptions. Our maxim of prudence asks readers to make energy decisions that are ethical or at least informed. Our maxim of agnosticism asks readers to look beyond a given energy technology to the services it provides and recognize that many systems can provide a desired service. We conclude that decisions in energy are justified by, if not predicated on, beliefs—beliefs which may or may not be supported by objective data, constantly blurring the line between fact, fiction, and frames. - Highlights: • Assumptions and values can play a combative, corrosive role in the generation of objective energy analysis. • Decisions in energy are justified by, if not predicated on, beliefs. • We propose six maxims for energy analysts and researcher.

Maximal isometric strength of the cervical musculature in 100 healthy volunteers

DEFF Research Database (Denmark)

Jordan, A; Mehlsen, J; Bülow, P M

1999-01-01

A descriptive study involving maximal isometric strength measurements of the cervical musculature.......A descriptive study involving maximal isometric strength measurements of the cervical musculature....

Maximization of Transuranic Deep-Burn in High Temperature Gas-Cooled Reactor

International Nuclear Information System (INIS)

Kim, Yong Hee; Kim, K. S.; Hong, S. G.; Shim, H. J.; Jo, C. K.; Lee, S. W.

2008-03-01

An optimization study of a single-pass transuranic (TRU) deep burn (DB) has been performed for a block-type modular helium reactor (MHR) proposed. A high-burnup TRU feed vector from light water reactors is considered. For three dimensional equilibrium cores, the performance analysis is done by using the Monte Carlo code McCARD. The core optimization is performed from the viewpoints of the core configuration, fuel management, TRISO fuel specification, and neutron spectrum. With regard to core configuration, two annular cores are investigated in terms of the neutron economy. A conventional radial shuffling scheme of fuel blocks is compared with an axial-only block-shuffling strategy in terms of the fuel bum up and core power distributions. The impact of the kernel size of the TRISO fuel is evaluated, and a diluted kernel, instead of a conventional concentrated kernel, is introduced to maximize the TRU burnup by reducing the self-shielding effects of the TRISO particles. In addition, it is shown that the core power distribution can be effectively controlled by a zoning of the packing fraction of the TRISO fuels. We also have shown that a long-cycle DB-MHR core can be designed by using a two- or three-batch fuel-reloading scheme, at the expense of only a marginal decrease of the TRU discharge bum up. Preliminary safety characteristics of a DBMHR core have been investigated in terms of the temperature coefficients and effective delayed neutron fraction. It has been found that, depending on the fuel management scheme and fuel specifications, the TRU burnup in an optimized DB-MHR core can be over 60% in a single-pass irradiation campaign. In addition, the equilibrium cycle mass balance analyses were also performed for 12 fuel cycles and the impact of TRU deep-bum on the repository was evaluated as well. Additionally, an SFR (Sodium Fast Reactor) fed with DB-MHR spent fuel were designed and characterized

Thermodynamic Analyses of Biomass Gasification Integrated Externally Fired, Post-Firing and Dual-Fuel Combined Cycles

Directory of Open Access Journals (Sweden)

Saeed Soltani

2015-01-01

Full Text Available In the present work, the results are reported of the energy and exergy analyses of three biomass-related processes for electricity generation: the biomass gasification integrated externally fired combined cycle, the biomass gasification integrated dual-fuel combined cycle, and the biomass gasification integrated post-firing combined cycle. The energy efficiency for the biomass gasification integrated post-firing combined cycle is 3% to 6% points higher than for the other cycles. Although the efficiency of the externally fired biomass combined cycle is the lowest, it has an advantage in that it only uses biomass. The energy and exergy efficiencies are maximized for the three configurations at particular values of compressor pressure ratios, and increase with gas turbine inlet temperature. As pressure ratio increases, the mass of air per mass of steam decreases for the biomass gasification integrated post-firing combined cycle, but the pressure ratio has little influence on the ratio of mass of air per mass of steam for the other cycles. The gas turbine exergy efficiency is the highest for the three configurations. The combustion chamber for the dual-fuel cycle exhibits the highest exergy efficiency and that for the post-firing cycle the lowest. Another benefit of the biomass gasification integrated externally fired combined cycle is that it exhibits the highest air preheater and heat recovery steam generator exergy efficiencies.

Nonadditive entropy maximization is inconsistent with Bayesian updating

Science.gov (United States)

Pressé, Steve

2014-11-01

The maximum entropy method—used to infer probabilistic models from data—is a special case of Bayes's model inference prescription which, in turn, is grounded in basic propositional logic. By contrast to the maximum entropy method, the compatibility of nonadditive entropy maximization with Bayes's model inference prescription has never been established. Here we demonstrate that nonadditive entropy maximization is incompatible with Bayesian updating and discuss the immediate implications of this finding. We focus our attention on special cases as illustrations.

Les Ambivalences du Silence: Les "Maximes" de la Rochefoucauld Par Quatre Chemins

Science.gov (United States)

Turcat, Eric

2012-01-01

Maxims are famous for their moral pronouncements, yet La Rochefoucauld's "Maximes" (1678) have become infamous for offering little moral guidance. Morally ambivalent at best, the "Maximes" are also less known for their other forms of ambivalence, whether rhetorical, psychological, anthropological or linguistic. Such are…

FLOUTS OF THE COOPERATIVE PRINCIPLE MAXIMS IN SBY’S PRESIDENTIAL INTERVIEWS

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Fahrus Zaman Fadhly

2012-12-01

Full Text Available This paper analyzed the presidential interviews of the President of Republic of Indonesia, Susilo Bambang Yudoyono (SBY, based on Grice’s theory of the Cooperative Principles (CP. This study employed a qualitative research design and the data were three transcripts of interview discourse between SBY and eight Indonesian journalists obtained through the presidential official website: http://www.presidentsby.info. The research investigated the ways of SBY in flouting the CP maxims in his presidential interviews and the functions of the flouts were. The research revealed that SBY flouted all the CP maxims and the maxim of Quantity was frequently flouted. Meanwhile, there were four ways used by SBY in flouting the CP maxims, i.e. hedging, indirectness, open answer and detailed element. The function of the flouts, i.e. face saving acts (FSA, self-protection, awareness, politeness, interestingness, control of information, elaboration and ignorance. This research also revealed that CP maxims of Grice are not universal.

Evaluation of anti-hyperglycemic effect of Actinidia kolomikta (Maxim. etRur.) Maxim. root extract.

Science.gov (United States)

Hu, Xuansheng; Cheng, Delin; Wang, Linbo; Li, Shuhong; Wang, Yuepeng; Li, Kejuan; Yang, Yingnan; Zhang, Zhenya

2015-05-01

This study aimed to evaluate the anti-hyperglycemic effect of ethanol extract from Actinidia kolomikta (Maxim. etRur.) Maxim. root (AKE).An in vitro evaluation was performed by using rat intestinal α-glucosidase (maltase and sucrase), the key enzymes linked with type 2 diabetes. And an in vivo evaluation was also performed by loading maltose, sucrose, glucose to normal rats. As a result, AKE showed concentration-dependent inhibition effects on rat intestinal maltase and rat intestinal sucrase with IC(50) values of 1.83 and 1.03mg/mL, respectively. In normal rats, after loaded with maltose, sucrose and glucose, administration of AKE significantly reduced postprandial hyperglycemia, which is similar to acarbose used as an anti-diabetic drug. High contents of total phenolics (80.49 ± 0.05mg GAE/g extract) and total flavonoids (430.69 ± 0.91mg RE/g extract) were detected in AKE. In conclusion, AKE possessed anti-hyperglycemic effects and the possible mechanisms were associated with its inhibition on α-glucosidase and the improvement on insulin release and/or insulin sensitivity as well. The anti-hyperglycemic activity possessed by AKE maybe attributable to its high contents of phenolic and flavonoid compounds.

Pilocarpine iontophoresis test

DEFF Research Database (Denmark)

Hjortskov, N; Jepsen, Leif; Nielsen, B

1995-01-01

The pilocarpine iontophoresis test (P-test) is used as a predictor of the capacity to produce sweat. Therefore, we studied the reproducibility of this test in 12 normal subjects on 10 consecutive days. Furthermore, we determined whether the P-test reflects whole-body and regional sweat secretion...... during exercise in the heat. Finally, we determined whether the P-test stimulates the eccrine sweat glands to maximal sweat secretion. Six growth hormone-deficient (GHD) patients who are known to have decreased sweating, and 11 healthy control subjects were studied. To induce maximal sweat secretion......, the patients exercised on a bicycle ergometer at a workload corresponding to 40% of their maximal aerobic power (VO2max). The 11 healthy subjects exercised at a workload of 150 W. All subjects exercised for 60 min in ambient air at 35 degrees C, with 50% relative humidity. The P-test showed a mean day...

Bipartite Bell Inequality and Maximal Violation

International Nuclear Information System (INIS)

Li Ming; Fei Shaoming; Li-Jost Xian-Qing

2011-01-01

We present new bell inequalities for arbitrary dimensional bipartite quantum systems. The maximal violation of the inequalities is computed. The Bell inequality is capable of detecting quantum entanglement of both pure and mixed quantum states more effectively. (general)

Maximally efficient protocols for direct secure quantum communication

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Anindita [Department of Physics and Materials Science Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP-201307 (India); Department of Physics and Center for Astroparticle Physics and Space Science, Bose Institute, Block EN, Sector V, Kolkata 700091 (India); Pathak, Anirban, E-mail: anirban.pathak@jiit.ac.in [Department of Physics and Materials Science Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP-201307 (India); RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Science of the Czech Republic, Faculty of Science, Palacky University, 17. Listopadu 12, 77146 Olomouc (Czech Republic)

2012-10-01

Two protocols for deterministic secure quantum communication (DSQC) using GHZ-like states have been proposed. It is shown that one of these protocols is maximally efficient and that can be modified to an equivalent protocol of quantum secure direct communication (QSDC). Security and efficiency of the proposed protocols are analyzed and compared. It is shown that dense coding is sufficient but not essential for DSQC and QSDC protocols. Maximally efficient QSDC protocols are shown to be more efficient than their DSQC counterparts. This additional efficiency arises at the cost of message transmission rate. -- Highlights: ► Two protocols for deterministic secure quantum communication (DSQC) are proposed. ► One of the above protocols is maximally efficient. ► It is modified to an equivalent protocol of quantum secure direct communication (QSDC). ► It is shown that dense coding is sufficient but not essential for DSQC and QSDC protocols. ► Efficient QSDC protocols are always more efficient than their DSQC counterparts.

Chamaebatiaria millefolium (Torr.) Maxim.: fernbush

Science.gov (United States)

Nancy L. Shaw; Emerenciana G. Hurd

2008-01-01

Fernbush - Chamaebatiaria millefolium (Torr.) Maxim. - the only species in its genus, is endemic to the Great Basin, Colorado Plateau, and adjacent areas of the western United States. It is an upright, generally multistemmed, sweetly aromatic shrub 0.3 to 2 m tall. Bark of young branches is brown and becomes smooth and gray with age. Leaves are leathery, alternate,...

Generalized Yosida Approximations Based on Relatively A-Maximal m-Relaxed Monotonicity Frameworks

Directory of Open Access Journals (Sweden)

Heng-you Lan

2013-01-01

Full Text Available We introduce and study a new notion of relatively A-maximal m-relaxed monotonicity framework and discuss some properties of a new class of generalized relatively resolvent operator associated with the relatively A-maximal m-relaxed monotone operator and the new generalized Yosida approximations based on relatively A-maximal m-relaxed monotonicity framework. Furthermore, we give some remarks to show that the theory of the new generalized relatively resolvent operator and Yosida approximations associated with relatively A-maximal m-relaxed monotone operators generalizes most of the existing notions on (relatively maximal monotone mappings in Hilbert as well as Banach space and can be applied to study variational inclusion problems and first-order evolution equations as well as evolution inclusions.

CANDU fuel cycle options in Korea

International Nuclear Information System (INIS)

Boczar, P. G.; Fehrenbach, P. J.; Meneley, D. A.

1996-01-01

There are many reasons for countries embarking on a CANDU R program to start with the natural uranium fuel cycle. Simplicity of fuel design, ease of fabrication, and ready availability of natural uranium all help to localize the technology and to reduce reliance on foreign technology. Nonetheless, at some point, the incentives for using natural uranium fuel may be outweighed by the advantages of alternate fuel cycles. The excellent neutron economy, on-line refuelling, and simple fuel-bundle design provide an unsurpassed degree of fuel-cycle flexibility in CANDU reactors. The easiest first step in CANDU fuel-cycle evolution may be the use of slightly enriched uranium (SEU), including recovered uranium from reprocessed LWR spent fuel. Relatively low enrichment (up to 1.2%) will result in a two- to three-fold reduction in the quantity of spent fuel per unit energy production, reductions in fuel-cycle costs, and greater flexibility in the design of new reactors. The CANFLEX (CANDU FLEXible) fuel bundle would be the optimal fuel carrier. A country that has both CANDU and PWR reactors can exploit the natural synergism between these two reactor types to minimize overall waste production, and maximize energy derived from the fuel. This synergism can be exploited through several different fuel cycles. A high burnup CANDU MOX fuel design could be used to utilize plutonium from conventional reprocessing or more advanced reprocessing options (such as co-processing). DUPIC (Direct Use of Spent PWR Fuel In CANDU) represents a recycle option that has a higher degree of proliferation resistance than dose conventional reprocessing, since it uses only dry processes for converting spent PWR fuel into CANDU fuel, without separating the plutonium. Good progress is being made in the current KAERI, AECL, and U. S. Department of State program in demonstrating the technical feasibility of DUPIC. In the longer term, CANDU reactors offer even more dramatic synergistic fuel cycles with PWR or

LEVEL OF ESTRADIOL 17-β SERUM AND OVARIAN FOLLICULARE DYNAMICS IN SHORT ESTROUS CYCLE OF BALI CATTLE

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C.M Airin

2014-09-01

Full Text Available The aims of the research were to confirm the short estrous cycles and determine the blood level ofestradiol 17-β and ovarian follicukar dynamics in these cases. The research was conducted using sevenBali cattle, approximately 2 years of age, kept in healthy condition with normal estrous cycles.Observation of estrus symptoms was performed daily. Ovarian follicles was examined and measuredusing ultrasonography started at the estrus day. Blood samples were collected from jugular vein, bloodsample collection and ultrasonographical examination of the ovaries were performed daily in the sametime. Serum level of estradiol 17-β was performed using EIA. The short cycle estrus were observed in 4Bali cattle (n=7 among natural estrous cycle. They have only one wave ovarian follicular developmentwhereas the maximal size of ovarian follicles ovulation likes the normal cycle The duration of shortestrous cycle was 7-10 days with normal usual estrus behavior. The peak of blood serum level was107.77 ± 55.94 pg/ml when the diameter dominant follicle of short estrous cycle was reached 10.5 ±0.38 mm. It can be concluded that the short estrous cycles may occur in Bali cattle after puberty amongnormal cycles.

Máxima fase estável de lactato é ergômetro-dependente em modelo experimental utilizando ratos Máxima fase de estabilidad de lactato es ergómetro-dependiente en modelo experimental utilizando ratones The maximal lactate steady state is ergometer-dependent in experimental model using rats

Directory of Open Access Journals (Sweden)

Fúlvia de Barros Manchado

2006-10-01

� 0,22 mM. Para el ejercicio en faja ergo métrica, se observó MFEL a 20 m.min-1, en concentración de 3,87 ± 0,33 mM. De esa forma, es posible concluir que la MFEL también es ergómetro-dependiente en modelos experimentales utilizando animales.The maximal lactate steady state (MLSS is considered the gold standard method for determination of aerobic/anaerobic metabolic transition during continuous exercise, but the blood lactate response at this intensity is ergometer-dependent in human beings. An important tool for exercise physiology and correlated fields is the use of animal models. However, investigation on evaluation protocols in rats is scarce. The aim of the present study was to verify if the MLSS is ergometer-dependent for the evaluation of the aerobic conditioning of rats. Therefore, 40 adult male Wistar rats were evaluated in two different exercise types: swimming and treadmill running. In both, the MLSS was obtained with 4 continuous 25 minutes tests, at different intensities, performed at 48 hours intervals. In all tests, blood samples were collected from a cut at the tail tip every 5 minutes for blood lactate analysis. The swimming tests occurred in a deep cylindrical tank, with water temperature at 31 ± 1°C. The loads used in the tests were 4.5; 5.0; 5.5 and 6.0% of the body weight tied to the animal's back. For MLSS determination in running exercise, there was selection of running rats and velocities used in the tests were 15, 20, 25, 30 m.min-1. The MLSS was interpreted as an increase not exceeding 1.0 mM of blood lactate, from the 10th to the 25th minute of exercise. The MLSS in swimming exercise occurred at 5.0% of body weight (bw, with blood lactate at 5.20 ± 0.22 mM. The running rats presented MLSS at the 20 m.min-1 velocity, with blood lactate of 3.87 ± 0.33 mM. The results indicated that the MLSS is ergometer-dependent in experimental models using animals, as it is in human beings.

Mutually Unbiased Maximally Entangled Bases for the Bipartite System Cd⊗ C^{dk}

Science.gov (United States)

Nan, Hua; Tao, Yuan-Hong; Wang, Tian-Jiao; Zhang, Jun

2016-10-01

The construction of maximally entangled bases for the bipartite system Cd⊗ Cd is discussed firstly, and some mutually unbiased bases with maximally entangled bases are given, where 2≤ d≤5. Moreover, we study a systematic way of constructing mutually unbiased maximally entangled bases for the bipartite system Cd⊗ C^{dk}.

Maximal near-field radiative heat transfer between two plates

Science.gov (United States)

Nefzaoui, Elyes; Ezzahri, Younès; Drévillon, Jérémie; Joulain, Karl

2013-09-01

Near-field radiative transfer is a promising way to significantly and simultaneously enhance both thermo-photovoltaic (TPV) devices power densities and efficiencies. A parametric study of Drude and Lorentz models performances in maximizing near-field radiative heat transfer between two semi-infinite planes separated by nanometric distances at room temperature is presented in this paper. Optimal parameters of these models that provide optical properties maximizing the radiative heat flux are reported and compared to real materials usually considered in similar studies, silicon carbide and heavily doped silicon in this case. Results are obtained by exact and approximate (in the extreme near-field regime and the electrostatic limit hypothesis) calculations. The two methods are compared in terms of accuracy and CPU resources consumption. Their differences are explained according to a mesoscopic description of nearfield radiative heat transfer. Finally, the frequently assumed hypothesis which states a maximal radiative heat transfer when the two semi-infinite planes are of identical materials is numerically confirmed. Its subsequent practical constraints are then discussed. Presented results enlighten relevant paths to follow in order to choose or design materials maximizing nano-TPV devices performances.

Increased cardiac output and maximal oxygen uptake in response to ten sessions of high intensity interval training.

Science.gov (United States)

Astorino, Todd A; Edmunds, Ross M; Clark, Amy; King, Leesa; Gallant, Rachael M; Namm, Samantha; Fischer, Anthony; Wood, Kimi A

2018-01-01

Increases in maximal oxygen uptake (VO2max) are widely reported in response to completion of high intensity interval training (HIIT), yet the mechanism explaining this result is poorly understood. This study examined changes in VO2max and cardiac output (CO) in response to 10 sessions of low-volume HIIT. Participants included 30 active men and women (mean age and VO2max=22.9±5.4 years and 39.6±5.6 mL/kg/min) who performed HIIT and 30 men and women (age and VO2max=25.7±4.5 years and 40.7±5.2 mL/kg/min) who served as non-exercising controls (CON). High intensity interval training consisted of 6-10 s bouts of cycling per session at 90-110 percent peak power output (PPO) interspersed with 75 s recovery. Before and after training, progressive cycling to exhaustion was completed during which CO, stroke volume (SV), and heart rate (HR) were estimated using thoracic impedance. To confirm VO2max attainment, a verification test was completed after progressive cycling at a work rate equal to 110%PPO. Data demonstrated significant improvements in VO2max (2.71±0.63 L/min to 2.86±0.63 L/min, Psessions of HIIT is due to improvements in oxygen delivery.

Interactive virtual reality Wii in geriatric day hospital: a study to assess its feasibility, acceptability and efficacy.

Science.gov (United States)

Chan, Tuen Ching; Chan, Fei; Shea, Yat Fung; Lin, Oi Yee; Luk, James Ka Hay; Chan, Felix Hon Wai

2012-10-01

Rehabilitation using interactive virtual reality Wii (Wii-IVR) was shown to be feasible in patients with different medical problems, but there was no study examining its use in a geriatric day hospital (GDH). The aim of the present study was to test the feasibility, acceptability and efficacy of Wii-IVR in GDH. It was a clinical trial with matched historic controls. Patients of a GDH were recruited to participate in Wii-IVR by playing "Wii Fit". Participants used a Wii controller to carry out movements involved in an arm ergometer. Each participant received eight sessions of Wii-IVR in addition to conventional GDH rehabilitation. Feasibility was assessed by the total time receiving Wii-IVR, the percentage of maximal heart rate reserve (%MHR) and Borg perceived exertion scale (BS) after participating in Wii-IVR. %MHR and BS were compared with those after carrying out an arm ergometer for the same duration. Acceptability was assessed by an interviewer-administered questionnaire. Efficacy was assessed by comparing improvements in Functional Independence Measure (FIM) between participants and matched historic controls, who received conventional GDH rehabilitations only. A total of 30 patients completed the study. Participants completed a total of 1941 min of event-free Wii-IVR. The mean %MHR was 15.9% ± 9.9% and the mean BS was 7.9 ± 2.3. There was no significant difference in %MHR and BS between participating in Wii-IVR and arm ergometer. Most participants found Wii-IVR similar to the arm ergometer, and would like to continue Wii-IVR if they had Wii at home. Improvements in FIM of participants were significantly more than that of historic controls. Wii-IVR in GDH was feasible and most participants accepted it. Participants had more improvements in FIM. © 2012 Japan Geriatrics Society.

Maximally entangled mixed states of two atoms trapped inside an optical cavity

International Nuclear Information System (INIS)

Li Shangbin; Xu Jingbo

2009-01-01

In some off-resonant cases, the reduced density matrix of two atoms symmetrically coupled with an optical cavity can very approximately approach maximally entangled mixed states or maximal Bell violation mixed states in their evolution. The influence of a phase decoherence on the generation of a maximally entangled mixed state is also discussed

IIB solutions with N>28 Killing spinors are maximally supersymmetric

International Nuclear Information System (INIS)

Gran, U.; Gutowski, J.; Papadopoulos, G.; Roest, D.

2007-01-01

We show that all IIB supergravity backgrounds which admit more than 28 Killing spinors are maximally supersymmetric. In particular, we find that for all N>28 backgrounds the supercovariant curvature vanishes, and that the quotients of maximally supersymmetric backgrounds either preserve all 32 or N<29 supersymmetries

Violations of Grice`s Maxims in The Prince and the Pauper Movie