Circadian rhythms and patterns of performance before and after simulated jet lag

1989 ◽  
Vol 257 (4) ◽  
pp. R796-R803 ◽  
Author(s):  
W. N. Tapp ◽  
B. H. Natelson
Keyword(s):  
Phase Shift ◽  
Discrimination Performance ◽  
Maximum Amplitude ◽  
Phase Advance ◽  
Light Cycle ◽  
Monkey Model ◽  
Before And After ◽  
Human Experiments ◽  
Temperature Rhythms ◽  
And Performance

We have developed a rhesus monkey model that enables us to investigate physiological rhythms and circadian effects on performance in an integrated framework. Monkeys worked for 8 h/day on a two-component task (a vigilance trial followed by a discrimination trial) for their daily food aliquot. Concurrently, we recorded activity and temperature rhythms around the clock. To test the model, we studied rhythms and performance during entrainment to a 24-h light cycle and after a 6-h phase advance. Results from this animal model displayed many of the essential characteristics seen in similar human experiments. During stable entrainment, temperature rhythms reached their maximum amplitude in late afternoon, with activity rhythms reaching their maximum amplitude several hours earlier. Performance exhibited consistent task-dependent variations over the course of daily sessions. Speed of discrimination performance was fastest at the beginning of the session, and speed of vigilance performance was fastest several hours later. After a 6-h phase advance, monkeys exhibited transient internal desynchrony with activity resynchronizing faster than temperature. Both vigilance and discrimination were impaired after the phase shift, with vigilance exhibiting larger-magnitude and longer-lasting impairments than discrimination. A second drop in performance was seen 10-14 days after the phase shift. These data replicate and extend earlier work in humans and show that this model can be used in the study of chronobiological questions that would be too expensive or too impractical to do with humans.

scholarly journals Effects of cooled floor pads combined with chilled drinking water on behavior and performance of lactating sows under heat stress

2021 ◽  
Vol 99 (3) ◽  
Author(s):  
Y Zhu ◽  
L J Johnston ◽  
M H Reese ◽  
E S Buchanan ◽  
J E Tallaksen ◽  
...  
Keyword(s):  
Drinking Water ◽  
Heat Stress ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
Time Budget ◽  
Video Recording ◽  
Lactating Sows ◽  
Before And After ◽  
And Performance ◽  
Drinking Frequency

Abstract This study was conducted to evaluate whether cooled floor pads combined with chilled drinking water could alleviate negative impacts of heat stress on lactating sows. Thirty sows (Landrace × Yorkshire, Parity = 1 to 6) were housed in individual farrowing stalls in two rooms with temperatures being controlled at 29.4°C (0700–1900 hours) and 23.9°C (1900–0700 hours). Sows in one room (Cool), but not in the other room (Control) were provided cooled floor pads (21–22°C) and chilled drinking water (13–15°C). Behavior of sows (15 sows/treatment) was video recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register the birth time of each piglet, from which total farrowing duration and birth intervals were calculated. The number of drinking bouts and the duration of each drinking bout were registered for each sow through viewing videos continuously for 2 h (1530–1730 hours) each video-recording day. Postures (lying laterally, lying ventrally, sitting, and standing) were recorded by scanning video recordings at 5-min intervals for 24 h each video-recording day, and time budget for each posture was calculated. Rectal temperature and respiration rate were measured for all sows the day before and after farrowing, and then once weekly. Sow and litter performance was recorded. Data were analyzed using the Glimmix procedure of SAS. The cooling treatment did not affect sow behavior or litter performance. Sows in the Cool room had lower rectal temperature (P = 0.03) and lower respiration rate (P < 0.001), consumed more feed (P = 0.03), tended to have reduced weight loss (P = 0.07), and backfat loss (P = 0.07) during lactation than sows in the Control room. As lactation progressed, sows increased drinking frequency (P < 0.001) and time spent lying ventrally (P < 0.0001), standing (P < 0.001), and sitting (P < 0.0001), and decreased time spent lying laterally (P < 0.0001) in both Cool and Control rooms. While cooled floor pads combined with chilled drinking water did not affect sow behavior, they did alleviate heat stress partially, as indicated by decreased rectal temperature, respiration rate, weight, and backfat loss, and increased feed intake in lactating sows.

scholarly journals Effects of Feeding Time on Markers of Muscle Metabolic Flexibility Following Acute Aerobic Exercise in Trained Mice Undergoing Time Restricted Feeding

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1717
Author(s):  
Aaron Persinger ◽  
Matthew Butawan ◽  
Martina Faietti ◽  
Ashley Pryke ◽  
Kyley Rose ◽  
...  
Keyword(s):  
Exercise Training ◽  
Performance Outcomes ◽  
Metabolic Flexibility ◽  
Feeding Time ◽  
Restricted Feeding ◽  
Physically Active ◽  
Impact Performance ◽  
Before And After ◽  
And Performance ◽  
Access To Food

Time-restricted feeding (TRF) is becoming a popular way of eating in physically active populations, despite a lack of research on metabolic and performance outcomes as they relate to the timing of food consumption in relation to the time of exercise. The purpose of this study was to determine if the timing of feeding/fasting after exercise training differently affects muscle metabolic flexibility and response to an acute bout of exercise. Male C57BL/6 mice were randomized to one of three groups for 8 weeks. The control had ad libitum access to food before and after exercise training. TRF-immediate had immediate access to food for 6 h following exercise training and the TRF-delayed group had access to food 5-h post exercise for 6 h. The timing of fasting did not impact performance in a run to fatigue despite TRF groups having lower hindlimb muscle mass. TRF-delayed had lower levels of muscle HSL mRNA expression and lower levels of PGC-1α expression but displayed no changes in electron transport chain enzymes. These results suggest that in young populations consuming a healthy diet and exercising, the timing of fasting may not substantially impact metabolic flexibility and running performance.

scholarly journals Effects of stimulus and task structure on temporal perceptual learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rannie Xu ◽  
Russell M. Church ◽  
Yuka Sasaki ◽  
Takeo Watanabe
Keyword(s):  
Temporal Discrimination ◽  
Discrimination Performance ◽  
Task Structure ◽  
Comparison Task ◽  
Interval Representation ◽  
Before And After ◽  
Temporal Intervals ◽  
Context Specific ◽  
Temporal Learning ◽  
And Task

AbstractOur ability to discriminate temporal intervals can be improved with practice. This learning is generally thought to reflect an enhancement in the representation of a trained interval, which leads to interval-specific improvements in temporal discrimination. In the present study, we asked whether temporal learning is further constrained by context-specific factors dictated through the trained stimulus and task structure. Two groups of participants were trained using a single-interval auditory discrimination task over 5 days. Training intervals were either one of eight predetermined values (FI group), or random from trial to trial (RI group). Before and after the training period, we measured discrimination performance using an untrained two-interval temporal comparison task. Our results revealed a selective improvement in the FI group, but not the RI group. However, this learning did not generalize between the trained and untrained tasks. These results highlight the sensitivity of TPL to stimulus and task structure, suggesting that mechanisms of temporal learning rely on processes beyond changes in interval representation.

Twenty Years After the Hype

2015 ◽  
Vol 2 (2) ◽  
pp. 1-21 ◽  
Author(s):  
Alois Paulin
Keyword(s):  
Performance Indicators ◽  
The State ◽  
Government Performance ◽  
Before And After ◽  
To Come ◽  
And Performance ◽  
Government Reforms

In this study the authors analyze the effects of e-government reforms that began in mid-90ies by confronting the promises which these reforms made to government performance in the period before and after the reforms took place. The authors use fiscal and performance indicators of the Slovenian government and courts to argue that e-government did not yield any notable effects on the state performance. Finally, the authors analyze the reasons why e-government technology cannot be regarded as sustainable and suggest a different approach towards researching how to sustainably improve governance for generations to come.

EFFECT OF REACTION TRAINING ON DURATION AND REACTION TIMES

2021 ◽  
Vol 7 (27) ◽  
pp. 86-92
Author(s):  
Tülin ATAN
Keyword(s):  
Reaction Time ◽  
Normal Distribution ◽  
Training Program ◽  
Reaction Times ◽  
Rank Test ◽  
Tennis Players ◽  
Before And After ◽  
Speed Performance ◽  
And Performance ◽  
Training Exercises

In this study, it was aimed to examine the effects of reaction training on reaction time and speed in tennis players. For this purpose a total of 18 tennis players; 9 male (age; 13.33 ± 1.80 years) and 7 female (13.85 ± 2.19 years) were voluntarily participated the study. In this study, the reaction training program, which was applied for 2 days a week for 12 weeks, was prepared in addition to tennis training. In the reaction training, exercises suitable for visual and auditory reaction were used. Before and after the 12-week reaction training, a 30 m speed running test and reaction time tests were performed. Whether the data showed normal distribution was analyzed with the Shapiro Wilk test and it was determined that the data did not show normal distribution. Mann Whitney U test was used in comparisons between the two groups. Wilcoxan Signd Rank test was used in the comparisons made before and after the training. As a result of the statistical analysis, it was seen that both the physical characteristics and performance parameters of males and females in our study group were not statistically different (p>0.05). For this reason, all subjects were taken into consideration regardless of gender in comparisons before and after tennis training. After the reaction training program applied to the subjects, it was determined that the 30 m speed performance values were shortened in duration compared to the pre-training period, that is, the speed improved (p <0.01). When the reaction time values were compared before and after the training program applied, it was seen that the reaction time values improved significantly after the training (p <0.01). As a result, reaction training performed in tennis players’ increases speed and reaction time performance. Reaction training is recommended in sports branches where this type of motor is important.

Equine hindlimb hoof biomechanics: an evaluation of the effect of routine hoof trimming on force and pressure distribution at midstance

2020 ◽  
Vol 16 (4) ◽  
pp. 333-337
Author(s):  
B. Faramarzi ◽  
M. Polniaszek ◽  
F. Dong
Keyword(s):  
Contact Pressure ◽  
Musculoskeletal Injuries ◽  
Medial Aspect ◽  
P Values ◽  
Pressure Plate ◽  
Before And After ◽  
And Performance ◽  
The Impact ◽  
Hindlimb Lameness ◽  
Paired T Test

Proper hoof function is vital for equine health and performance. Many musculoskeletal injuries in horses originate from the foot. Most studies performed to date have focused on the forehoof while the hindhoof (HH) has received less attention. Our goal was to examine the influence of routine hoof trimming on HH medio-lateral hoof balance. The objective of this study was to examine force (F), contact pressure (CP), and contact area (CA) at the medial and lateral aspects of the HH to evaluate the impact of routine hoof trimming on HH biomechanics. Clinically sound Arabian horses (n=9) were walked across a calibrated pressure plate before and after routine hoof trimming and the F, CP, and CA at the medial and lateral aspects of the HH were recorded at midstance pre- and post-trimming. The differences between these regions were investigated using a paired T-test. P-values <0.05 were considered significant. Among measured variables, force increased by 25% (P=0.007) and contact pressure increased by 13% (P=0.032) at the medial aspect of the HH after routine hoof trimming. Analysing data from hindlimb hoof-surface interaction in sound horses will allow for a better understanding of imbalances that may lead to pathologies and hindlimb lameness in horses.

scholarly journals Effects of Lean Tools in Achieving Lean Warehousing

2016 ◽  
Vol 54 (4) ◽  
pp. 517-534 ◽  
Author(s):  
Aleksandra Anđelković ◽  
Marija Radosavljević ◽  
Danijela Stošić
Keyword(s):  
Lean Principles ◽  
Before And After ◽  
Lean Tools ◽  
And Performance ◽  
The Individual ◽  
Warehouse Operations

Abstract The acceptance of lean philosophy in the company means not only respecting the lean principles in the manufacturing but in all the processes that are performed inside the company. All processes in the company that are a potential places for making losses and waste and thus require the application of lean principles. Among others, warehouse and warehouse operations, as a centre of costs and waste, must be supported through the implementation of lean philosophy in the company by respecting lean principles. The implementation of lean principles in the warehouse is a certain step of improvement warehouse process and performance, but also of the whole company. In that sense, the paper presents the analysis of the warehousing process and its performances before and after implementation of the lean tools in a selected Serbian company as a practical example. In addition, research shows which parts of warehousing need to be improved, in analysed company, as well as correlation between the individual parts of warehousing, according to employees' opinion from next sectors: purchasing, production and logistics.

scholarly journals Clinical instructors’ perceptions of virtual reality in health professionals’ cardiopulmonary resuscitation education

2018 ◽  
Vol 6 ◽  
pp. 205031211879960 ◽  
Author(s):  
Marie Ann Mae En Wong ◽  
Shien Chue ◽  
Michelle Jong ◽  
Ho Wye Kei Benny ◽  
Nabil Zary
Keyword(s):  
Virtual Reality ◽  
Cardiopulmonary Resuscitation ◽  
Clinical Education ◽  
Health Professionals ◽  
Future Research ◽  
Memory Enhancement ◽  
Current Health ◽  
Key Stakeholders ◽  
Before And After ◽  
And Performance

Objectives: Cardiopulmonary resuscitation (CPR) is lifesaving. Yet, cardiac arrest survival remains low despite CPR intervention. Education has been highlighted as a strategy to overcome this issue. Virtual Reality technology has been gaining momentum in the field of clinical education. Published studies report benefits of virtual reality for CPR education; yet, perceptions of CPR instructors towards virtual reality remain unexplored. CPR instructors are key stakeholders in CPR education and their perceptions are valuable for the design and adoption of virtual reality-enhanced learning. The purpose of this study is therefore to understand the perceptions of CPR instructors towards using virtual reality for health professionals’ CPR education. The aim was addressed via three research questions: (1) What are the perceptions of CPR instructors towards current health professionals’ CPR education? (2) What are the perceptions of CPR instructors towards features of virtual reality ideal for health professionals’ CPR education? (3) What are the perceptions of CPR instructors towards the potential role of virtual reality in health professionals’ CPR education? Methods: A total of 30 CPR instructors were surveyed on their views towards current health professionals’ CPR education and the use of virtual reality for health professionals’ CPR education, before and after interacting with a CPR virtual reality simulation. Responses were analysed using interpretative thematic analysis. Results: CPR instructors perceived current health professionals’ CPR education as limited due to unideal test preparation (resources, practice, motivation, and frame of mind) and performance. They perceived fidelity, engagement, resource conservation, and memory enhancement as features of virtual reality ideal for health professionals’ CPR education. Virtual reality was viewed by CPR instructors as having potential as a blended learning tool, targeting both ‘novice’ and ‘experienced’ health professionals. Conclusion: The study highlighted the gaps in current health professionals’ CPR education that can be addressed using virtual-reality-enabled learning. Future research could investigate virtual reality simulations with features desirable for CPR education of target populations.

Caffeine counteracts the ergogenic action of muscle creatine loading

1996 ◽  
Vol 80 (2) ◽  
pp. 452-457 ◽  
Author(s):  
K. Vandenberghe ◽  
N. Gillis ◽  
M. Van Leemputte ◽  
P. Van Hecke ◽  
F. Vanstapel ◽  
...  
Keyword(s):  
Intermittent Exercise ◽  
Creatine Supplementation ◽  
Knee Extensors ◽  
Caffeine Intake ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Before And After ◽  
And Performance ◽  
Exercise Fatigue ◽  
Voluntary Contractions

This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.

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