Run Trials Research Articles

Screening and statistical optimization of anti-cancer L-methionase enzyme produced by Aspergillus fumigatus MF13 using response surface methodology

Cancer research focuses on new pharmacological agents. Enzymatic approaches have shown promise in reducing cancer burden in experimental models. In this study, Aspergillus fumigatus, a new high-productivity L-methionine-producing fungus, was isolated from soil samples. The enhancement of enzyme production by A. fumigatus was carried out using the method. One-factor-at-a-time for seven different parameters: temperature (25°C, 30°C, 35°C, and 40°C), pH (6 to 10), incubation time (4 to 8 days), inoculum (1% to 3%), substrate concentration (0.2% to 0.5%), and various carbon sources (glucose, fructose, maltose, and lactose), and organic and inorganic nitrogen sources (Yeast extract, peptone, potassium nitrate, and ammonium sulfate). The statistical method, Plackett-Burman (PB), and response surface method design were used for optimization using Design Expert 13 software. The PB formula consisted of 12 run trials and 9 factors: temperature, pH, glucose, and yeast extract. Incubation time: dipotassium phosphate, potassium nitrate, magnesium sulfate, and potassium chloride Three important parameters were identified in this analysis: temperature, yeast extract, and dipotassium phosphate with p-values <0.05. The enzyme yield was then optimized using these important parameters through central composite design with 20 run trials; the highest L-methionase enzyme production was achieved at 30°C, with a yeast extract concentration of 2.4 g/l and a dipotassium phosphate concentration of 1.2 g/l. Regression model analysis resulted in the R2 value of 96.5%, indicating that it was well suited to describe the relationship between the response and the variables.

A comparative analysis of big data processing paradigms: Mapreduce vs. apache spark

The paper addresses a highly relevant and contemporary topic in the field of data processing. Big data is a crucial aspect of modern computing, and the choice of processing framework can significantly impact performance and efficiency. The technical revolution of big data has changed how organizations handle and value large databases. As data quantities expand quickly, effective and scalable data processing systems are essential. MapReduce and Apache Spark are two of the most popular large data processing techniques. This study compares these two frameworks to determine their merits, shortcomings, and applicability for big data applications. Nearly quintillion bytes of data are created daily. Approximately 90% of data was produced in the previous two years. At this stage, data comes from temperature sensors, social media, movies, photographs, transaction records (like banking records), mobile phone conversations, GPS signals, etc. In this article, all key big data technologies are introduced. This document compares all big data technologies and discusses their merits and downsides. Run trials using multiple data sets of varying sizes to validate and explain the study. Graphical depiction shows how one tool outperforms others for given data. Big Data is data generated by the rapid usage of the internet, sensors, and heavy machinery, with great volume, velocity, variety, and veracity. Numbers, photos, videos, and text are omnipresent in every sector. Due to the pace and amount of data generation, the computing system struggles to manage large data. Data is stored in a distributed architectural file system due to its size and complexity. Big distributed file systems, which must be fault-tolerant, adaptable, and scalable, make complicated data analysis dangerous and time-consuming. Big data collection is called ‘datafication’. Big data is ‘datafied’ for productivity. Organisation alone does not make Big Data valuable; we must choose what we can do with it.

Comparison of energy expenditure and substrate oxidation between walking and running in men and women.

[Purpose]The present study compared energy metabolism between walking and running at equivalent speeds during two incremental exercise tests.[Methods]Thirty four university students (18 males, 16 females) were recruited. Each participant completed two trials, consisting of walking (Walk) and running (Run) trials on different days, with 2-3 days apart. Exercise on a treadmill was started from initial stage of 3 min (3.0 k/m in Walk trial, 5.0 km/h in Run trial), and the speed for walking and running was progressively every minute by 0.5 km/h. The changes in metabolic variables, heart rate (HR), and rating of perceived exertion (RPE) during exercise were compared between the trials.[Results]Energy expenditure (EE) increased with speed in each trial. However, the Walk trial had a significantly higher EE than the Run trial at speeds exceeding 92 ± 2 % of the maximal walking speed (MWS, p < 0.01). Similarly, carbohydrate (CHO) oxidation was significantly higher in the Walk trial than in the Run trial at above 92 ± 2 %MWS in males (p < 0.001) and above 93 ± 1 %MWS in females (p < 0.05).[Conclusion]These findings suggest that EE and CHO oxidation during walking increase non-linearly with speed, and walking at a fast speed causes greater metabolic responses than running at the equivalent speed in young participants.

Unified Approach for the Design, Manufacture and Test of an Off-Road Rubber Tracked Ground Vehicle (TGV)

The work in this paper proposes a unified approach which involves the design, manufacture, and test an off-road rubber tracked ground vehicle for rugged terrain conditions. The proposed vehicle overall design consists of rubber tracking system, main chassis, power train and transmission system,, steering system, suspension system and the vehicle body. The design approach of the rubber tracking system can be considered new, simple, easy to manufacture and cheap compared with what is available in the literature. The dimensions of the designed rubber tracking system are of contact length of 1700 mm, track height of 850 mm, and track width of 380 mm. The overall proposed design weight of the vehicle is 14.714 kN of 3500 mm length, 2000 mm wide, 1550 mm height with minimum ground clearance of 200 mm. A 165hp Subaru gasoline engine with transmission system, suspension system, braking system, exhaust and fuel system were selected, other parts of the vehicle were designed and manufactured such as the main chassis, rubber tracking system, steering system. Finally, the vehicle was tested and after several run trials, it was performing successfully.

Acute Caffeine Mouth Rinse Does Not Change the Hydration Status following a 10 km Run in Recreationally Trained Runners.

Background and Aims Caffeine mouth rinsing has emerged as an alternative to oral caffeine consumption for improving performance without provoking lower gastrointestinal distress. However, it remains unclear if hydration status and sweat rate are negatively affected by caffeine mouth rinsing. This study is aimed at evaluating the effects of 10 seconds of caffeine mouth rinsing (1.2% anhydrous caffeine solution) on hydration status and sweat rate following a 10 km run trial. Methods Ten recreationally trained runners (30.1 ± 6.4 y) volunteered to participate in this double-blind, placebo-controlled, and crossover research study. Participants completed two 10 km run trials separated by approximately one week. Immediately prior to running, participants completed a 10-second mouth rinse protocol with either 300 mg of caffeine or microcrystalline cellulose (placebo) diluted in 25 mL of water. The effects of caffeine mouth rinsing on hydration status and sweat rate were assessed following a 10 km run trial. Results Sweat rate (placebo: 15.34 ± 9.71 vs. caffeine: 11.91 ± 6.98 mL · min−1; p = 0.39), dehydration (placebo: 1.20 ± 0.57 vs. caffeine: 1.49 ± 0.29%; p = 0.15), and hydration (placebo: 15.32 ± 9.71 vs. caffeine: 11.89 ± 6.99 mL · min−1; p = 0.37) measures were not significantly different between trials. Conclusion Caffeine mouth rinse does not appear to alter the hydration status or sweat rate following a 10 km run.

Heuristic approach to minimise the energy consumption of sensors in cloud environment for wireless body area network applications

The wireless sensor networks are single user centric and end users who do not own sensors are unable to have access to any wireless network specific application. This sensor cloud is a new paradigm to manage the physical sensors which are deployed in any WSN application. Existing research work on sensor cloud is limited to guaranteeing minimal energy consumption. In this paper, a novel mathematical model based on virtual sensor grouping is proposed to minimise the cumulative energy consumption of sensors in cloud environment. Energy consumption of non-virtual sensor with virtual sensor group for two different applications is compared and the results are shown. Further the proposed sensor cloud infrastructure with power model is compared with traditional WSN with respect to energy efficiency, throughput and performance with quick synchronisation time for random run trials and results were found to be better than the conventional WSN.

Cardiometabolic and Perceptual Responses to Maximal Exercise: Comparing Graded Walking to Ungraded Running

Graded exercise testing for determination of aerobic capacity can be conducted in numerous ways with treadmill testing representing the primary modality. Achieving maximal effort on a treadmill can be accomplished by increasing speed and/or grade. Research to date comparing graded walking maximal tests to ungraded running tests is limited. PURPOSE: Compare the cardiometabolic responses to two treadmill-based maximal tests, namely graded walking and ungraded running. METHODS: 20 healthy participants (11 females, 9 males; mean BMI = 25; mean age = 24) completed two counterbalanced cardiometabolic exercise tests. The WALK trial started with a brisk and comfortable walking speed and increased grade by 2% every minute until exhaustion and the RUN trial started with a comfortable walking speed and increased by 0.5 mph every minute until exhaustion. Expired gases, HR, overall RPE (RPE-O), and legs only RPE (RPE-L) were assessed during the test. RESULTS: Data was analyzed using dependent t-tests. The RUN and WALK trials produced similar maximal values for RPE-O, RPE-L, and VO2 (all p-values > 0.05; all ES values < 0.2), though HR was significantly higher in the RUN trial (p < 0.05; ES = 0.4), and RER was significantly higher in the WALK trial (p < 0.01; ES = 0.8). CONCLUSIONS: Findings indicate that both walk-based and run-based exercise tests produce similar perceptual responses that indicate maximal effort, and similar VO2max values despite very different approaches to creating intense work. The observed difference in HR suggests that a run-based maximal exercise test produces a greater cardiovascular response, while the higher RER value within the walk-based maximal exercise test suggests greater metabolic acidosis. Results support treadmill exercise testing as a flexible multiple assessment modality.

Effects of Pre-exercise Caffeinated Energy Drink Consumption on Running Performance.

PURPOSE: The purpose of this study was to examine the effects of pre-exercise consumption of a commercially available caffeinated energy drink on running performance in healthy adult subjects. METHODS: Eight adult subjects (50% female; Age: 31.1+6.0 y, Ht: 175.3+46.8 cm, Wt: 77.7+7.5 kg, BMI: 25.30+2.2 kg/m2) provided their informed consent for participation. All subjects had at least a 3-month history of regular running (at least 30 min, 3 times per week) and were typical consumers of caffeine (at least weekly). Subjects first completed a progressive treadmill running protocol to determine VO2 peak, with continuous measurement of VO2 (indirect calorimetry) and HR (wireless heart monitor). Blood pressure (auscultation) and RPE (Borg ratio scale) were assessed at each workload. Subjects returned for two performance-running trials, staged at least one week apart. One hour prior to each run, subjects consumed a commercially available caffeinated drink (CAF) (MonsterÒ Rehab®, containing 1.48 mg caffeine/kg body weight), or a similar tasting, non-caffeinated placebo drink (PLA). Both drinks contained an equal amount of carbohydrate (3 gm) per serving. Drinks were administered in a double-blind fashion. Subjects then completed a 30-minute run at a pace corresponding to 70-75% VO2 peak, and then ran at 90% VO2peak until volitional fatigue. VO2 and HR were monitored continuously throughout the performance run. BP and RPE were obtained every 5 minutes of the first 30 minutes and at conclusion of the run. Performance time at 90% VO2peak was recorded. Mean values for all measured variables between trials were assessed for differences (p<0.05) via repeated measures ANOVA. RESULTS: During the run trials, no significant differences were seen in VO2, METS, %fat used, %carbohydrate used, HR, RPE, and BP. RER at 5 min of the run was significantly (p=0.046) reduced in the CAF trial. Mean run time at 90% VO2peak (8.96 min PLA, 9.46 min CAF) was not significantly different (p=0.37) or clinically meaningful (effect size=0.08). CONCLUSIONS: Pre-exercise consumption of a commercially available caffeinated energy drink failed to significantly impact metabolic / cardiovascular function and performance run time in recreational adult runners.

Sweat responses during inactive recovery after high-intensity running in hot, dry and humid conditions

This study investigated the relationship between high (85%) and low (19%) relative humidity (RH) and sweat rate during inactive recovery after high-intensity work in a hot environment (30 °C). Ten male subjects performed two 20-minute run trials at 68 ± 4 % of maximal oxygen consumption (VO 2max ) followed by 36 minutes of inactive recovery in standing position. Regional sweat rate (RSR) was measured on the forearm and mid-central back by technical absorbent pads, and gross sweat loss was estimated from change in body weight. Core temperature (T c ) and six skin temperatures for calculation of mean skin temperature (T s ) were measured continuously together with heart rate (HR) during running and recovery. Results show that RSR was significantly (p<0.05) higher for both arm and back during running and inactive recovery in 85% RH compared to 19% RH. The highest sweat rate was observed on the back during the last five minutes of running in 85% RH (1387 g·m -2 ·h -1 ) compared to 19% RH (886 g·m -2 ·h -1 ). Gross sweat loss (GSL) was significantly higher in 85% RH (796 ± 414 g·h -1 ) than 19% RH (489 ± 140 g·h -1 ) conditions (p=0.010). T c continued to increase for three and seven minutes post-exercise in 19% RH and 85% RH, respectively and T s was significantly higher in 85% RH than in 19% RH (p<0.05). HR was 11 bpm higher after running in 85% RH compared to 19% RH (p=0.001). In conclusion, RSR and GSL, as well as HR, T c and T s was higher during post-exercise recovery in 30°C and 85% RH than in 30°C and 19% RH. This study emphasises the importance of including the effect of relative humidity in assessment of both exercise and recovery.

Shorter Ground Contact Time and Better Running Economy: Evidence From Female Kenyan Runners.

Mooses, M, Haile, DW, Ojiambo, R, Sang, M, Mooses, K, Lane, AR, and Hackney, AC. Shorter ground contact time and better running economy: evidence from female Kenyan runners. J Strength Cond Res 35(2): 481-486, 2021-Previously, it has been concluded that the improvement in running economy (RE) might be considered as a key to the continued improvement in performance when no further increase in V̇o2max is observed. To date, RE has been extensively studied among male East African distance runners. By contrast, there is a paucity of data on the RE of female East African runners. A total of 10 female Kenyan runners performed 3 × 1,600-m steady-state run trials on a flat outdoor clay track (400-m lap) at the intensities that corresponded to their everyday training intensities for easy, moderate, and fast running. Running economy together with gait characteristics was determined. Subjects showed moderate to very good RE at the first (202 ± 26 ml·kg-1·km-1) and second (188 ± 12 ml·kg-1·km-1) run trials, respectively. Correlation analysis revealed significant relationship between ground contact time (GCT) and RE at the second run (r = 0.782; p = 0.022), which represented the intensity of anaerobic threshold. This study is the first to report the RE and gait characteristics of East African female athletes measured under everyday training settings. We provided the evidence that GCT is associated with the superior RE of the female Kenyan runners.

Impact of Blood Flow Restricted Cycle Training in College-Aged Triathletes on Performance and Physiological Parameters

Aerobic exercise training with blood flow restriction (BFR) has been reported to increase aerobic capacity and muscle strength and volume. However, there is no evidence that such a training strategy increases performance in athletes. PURPOSE: To elucidate the effects of a 4 week BFR cycle training protocol on aerobic capacity, muscle function and performance variables in triathletes of a university club. METHODS: Eighteen healthy university triathletes were randomly assigned to BFR group (n = 12; 19 ± 1 yrs) or no BFR group serving as the control (CON; n = 6; 20 ± 1 yrs). Both groups trained by cycling for 30 minutes, 3 days/week for 4 weeks. BFR was performed for 15 minutes total during each session as 5 minutes with BFR followed by 5 minutes without BFR, by applying cuffs to the upper thighs. The BFR group was further subdivided into two groups: one group with compression set to 160 mmHg (constant pressure, BFR-CP, n = 6); in the other, the compression was gradually increased from 160 to190 mmHg over 4 weeks (incremental pressure, BFR-IP, n = 6). All tests were performed before (Pre) and after 4 weeks of training (Post). Triathlon-specific performance tests were used: 5000-m run and 1500-m swim time trials and a 20-min bike distance trial, as well as the evaluation of peak oxygen uptake (VO2peak), one legged knee extensor strength, and thigh muscle cross sectional area (CSA). Two-way repeated ANOVAs were used (BFR vs CON or BFR-CP vs BFR-IP and Pre vs Post) with significance accepted as p<0.05. RESULTS: VO2peak significantly increased after the training (main effect of time) and significant group-by-time interactions were detected (3198 to 3449 mL/min and 3152 to 3212 mL/min in BFR and CON). However, a post-hoc analysis indicated no significant interaction in VO2peak between BFR-CP (3137 to 3396 mL/min) and BFR-IP (3259 to 3501 mL/min). Although the 5000-m run time was significantly shorter after the training (main effect of time), no significant interaction were detected (20.3 to 19.8 min and 20.1 to 19.8 min in BFR and CON). Lastly, there were no significant effects of training on muscle strength or CSA, 1500-m swim time, or 20-min bike distance. CONCLUSIONS: In this group of university triathletes, 4 weeks of BFR cycle training increased aerobic capacity, but had no added effect on muscle strength and volume or performance test outcomes.

Classification of mouth movements using 7 T fMRI

Objective. A brain–computer interface (BCI) is an interface that uses signals from the brain to control a computer. BCIs will likely become important tools for severely paralyzed patients to restore interaction with the environment. The sensorimotor cortex is a promising target brain region for a BCI due to the detailed topography and minimal functional interference with other important brain processes. Previous studies have shown that attempted movements in paralyzed people generate neural activity that strongly resembles actual movements. Hence decodability for BCI applications can be studied in able-bodied volunteers with actual movements. Approach. In this study we tested whether mouth movements provide adequate signals in the sensorimotor cortex for a BCI. The study was executed using fMRI at 7 T to ensure relevance for BCI with cortical electrodes, as 7 T measurements have been shown to correlate well with electrocortical measurements. Twelve healthy volunteers executed four mouth movements (lip protrusion, tongue movement, teeth clenching, and the production of a larynx activating sound) while in the scanner. Subjects performed a training and a test run. Single trials were classified based on the Pearson correlation values between the activation patterns per trial type in the training run and single trials in the test run in a ‘winner-takes-all’ design. Main results. Single trial mouth movements could be classified with 90% accuracy. The classification was based on an area with a volume of about 0.5 cc, located on the sensorimotor cortex. If voxels were limited to the surface, which is accessible for electrode grids, classification accuracy was still very high (82%). Voxels located on the precentral cortex performed better (87%) than the postcentral cortex (72%). Significance. The high reliability of decoding mouth movements suggests that attempted mouth movements are a promising candidate for BCI in paralyzed people.

Economics and industry do not mean ethical conduct in clinical trials.

Clinical trials present an ethical dilemma for pharmaceutical companies. While companies may want to undertake and report these trials in an ethical manner, negative results can significantly affect product sales. There is accumulating evidence that company-financed trials are biased in favor of the product that the company makes. Ethical conduct in this article is defined as whether the trials are conducted in the best interests of the participants and/or reported in the best interests of patients. Nine examples of how clinical trials are violating multiple articles in the Declaration of Helsinki are discussed using concrete case reports from the literature. The recognition of ethical problems in company run trials is not something new, but to date no meaningful action has been taken to resolve this issue. What is necessary is to separate the financing of clinical trials from their conduct.

Scalar-linear increases in perceived exertion are dissociated from residual physiological responses during sprint-distance triathlon

ObjectiveThis study examined how residual fatigue affects the relationship between ratings of perceived exertion (RPE), physiological responses, and pacing during triathlon performance. MethodsEight male triathletes completed a sprint-distance triathlon (750m swim, 20kmcycle and 5km run) and isolated 5km run on separate days. RPE, core temperature (Tcore), heart rate and blood lactate concentration [BLa−] were recorded during both, in addition to performance time and speed. ResultsTriathlon run time (1248±121s) was significantly slower than the isolated run (1167±90s) (p<0.01). Significant differences were observed at the start of the two conditions for all physiological measures (Heart rate 162±4 vs 154±5 beatsmin−1; Tcore 38.3±0.8 vs 36.7±0.6C; [BLa−] 9.1±2.8 vs 2.1±0.4mmolL−1, for triathlon and isolated run, respectively, p<0.05). No significant differences were observed for initial RPE (p=0.083), rate of RPE increase (p=0.412), or final RPE (p=0.329) between run trials. ConclusionsThe maintenance of a scalar-linear increase in RPE by the brain remains the primary mechanism for pace regulation during both single and multi-modal endurance performance, with physiological responses being only indirectly related to this process. The apparent absence of any RPE ‘resetting’ between disciplines suggests that during shorter distance multi-sport performances (60–90 min) a cognitive pacing strategy for the entire event is employed. However, as subtle alterations in RPE development between disciplines were observed the existence of discipline-specific RPE ‘templates’ should not be discounted.

The Timing of Fluid Intake during an Olympic Distance Triathlon

Seven highly trained male triathletes, aged 18 to 35 years, were tested during two simulated Olympic distance triathlons to determine whether run performance was enhanced when consuming 177 ml of water at 8, 16, 24, and 32 kilometers (Early Trials) compared to consumption at 10, 20, 30, and 40 kilometers (Late Trials), during the cycling segment of the triathlon. Swim times for 1500 m were similar between trials; 40-km cycling times were approximately 10 s faster during the Late Trials; however, 10-km run times were faster during the Early Trials (P < 0.02). No significant differences between run trials were found for the rating of perceived exertion, oxygen uptake, heart rate, and change in urine specific gravity. It was concluded that the consumption of fluids earlier in the cycle phase of the Olympic distance triathlon benefits the run and overall performance time.

Laser welding of copper–nickel alloys: a numerical and experimental analysis

Melt run trials were carried out on Cu–Ni bars using a CO2 laser source in order to analyse the effects of welding parameters (i.e. laser power, welding speed) on geometrical characteristics and on the microstructure of the bead. Experimental results were then used to determine the source parameters to be employed in a finite element model (FEM) of the welding process, with particular attention paid to the thermal field induced by the laser beam. A specific procedure, named 'automatic remeshing technique', was used in order to minimise the computation time. The aim was to create a reliable numerical model, suitable for the optimisation, in practical cases, of welding processes of these kinds of materials. A good correlation, in terms of predicted cooling rates, with the values calculated from SDAS measurements, was observed.

Investigation of electron-beam welding in wrought Inconel 706—experimental and numerical analysis

Electron-beam welding (EBW) is commonly employed in the aeroengine industry for the welding of high integrity components, fabricated from high-strength superalloys. For such applications, it is important to predict distortions and residual stresses induced by the process. Melt run trials have been carried out on nickel-base superalloy Inconel 706 plates using the EBW technique in order to analyse the effects of welding parameters on geometrical characteristics and microstructure of the bead. Butt-welded plates have been then investigated by means of tensile tests, microstructural analysis, and X-ray diffraction measurements. A finite element model of the process has been set up using an uncoupled thermal–mechanical analysis. The heat source was modelled using a superimposition of a spherical and a conical shape heat source with Gaussian power density distribution in order to reproduce the nail shape of the fusion zone (FZ). The parameters of the source were chosen so that the model would match with experimentally determined weld pool shape and temperatures, measured with thermocouples. Subsequently, the thermal analysis was used to drive the non-linear mechanical analysis. The predicted residual stresses were then compared with X-ray diffraction measurements. It was found that the correct thermal and residual stresses prediction is influenced by the shape of the fusion zone, the highest thermal tensile stress arising under the nailhead of the fusion zone where microfissuring can be observed.

Ventilatory responses during varied stride and pedal frequencies

The effects of limb movement frequency during walking and running and cycling at 60 and 90 rpm on the ventilatory responses were studied in 19 male subjects. Ten of the subjects were trained runners whereas nine of the subjects were trained cyclists. The runners completed walk and run exercise trials at equal levels of CO 2 excretion (V̇ CO 2 ) and low (≈60) rpm and high (≈90) rpm cycling trials at equal V̇ CO 2 levels. The cyclists completed low and high rpm cycling trials at equal V̇ CO 2 levels. The cyclists were not tested on the walk/run trials as they had been tested previously and had been shown to have similar ventilatory responses when walking and running at equal V̇ CO 2 levels. Minute ventilation (V̇ e), tidal volume (V t), breathing frequency (f), end-tidal CO 2 ( Pet CO 2 )_tensions, and inspiratory (T i) and expiratory (T e) times were not found to differ significantly between the low and high pedal frequency trials for either the cyclists or the runners. No significant differences were found in estimated arterial CO 2 tensions (Pa CO 2 ) or estimated alveolar ventilation (V̇ a) between the cycling trials for either the runners or the cyclists. When comparing running to walking, the runners were found to have a greater V̇ e and estimated V̇ a. This was mediated by an increase in f as V t was found to decrease. The increased f was associated with a shortened T i as T e was not significantly different between the walk and run trials. End-tidal CO 2 tension and estimated Pa CO 2 was significantly lower during the run trial as compared to the walk trial. These results suggest some form of neurogenic stimuli influencing ventilation in the runners while running. This same neurogenic influence is not present when cyclists run and when either cyclists or runners exercise on the bicycle. A possible source for the neurogenic stimuli is discussed.

Ratings of perceived exertion in individuals with varying fitness levels during walking and running.

It was the purpose of this investigation to: 1) compare the ratings of perceived exertion (RPEs) in high and low fit individuals when walking and running at comparable exercise intensities and 2) to determine if ventilation (VE) provides a central signal for RPEs. Nine high fit and nine low fit male subjects completed two exercise bouts on a treadmill, one uphill walking and the other level running. Workloads for each bout were set at 90% of each subject's ventilatory threshold (VT) as determined from a graded exercise test. Oxygen consumption (Vo2), heart rate (HR), and VE were all similar between the walk and run trials for the low fit subjects (P greater than 0.05). HR were found to be significantly greater during the walk trial vs. the run trial (P less than 0.05) for the high fit subjects, whereas, VE was significantly greater during the run trial. Oxygen consumption was similar for the high fit subjects during both trials (P greater than 0.05). During the walk and run trials, central (12.1 +/- 1.6 vs. 11.4 +/- 1.5), local (14.0 +/- 1.3 vs. 13.9 +/- 1.1) and overall (12.8 +/- 1.2 vs. 12.4 +/- 1.4) RPEs were not found to be significantly different for the low fit group (P greater than 0.05). In contrast, during the walk vs. the run trial there was a significant increase in central (10.7 +/- 2.0 vs. 9.2 +/- 1.9), local (11.5 +/- 2.0 vs. 9.8 +/- 1.8) and overall (11.2 +/- 2.4 vs. 9.6 +/- 2.3) RPEs for the high fit group (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A discrete software reliability growth model with two types of errors

AbstractAs the social missions of computer systems increase, it becomes more important to develop high‐reliability software. For this reason software systems are tested repeatedly to remove latent errors in the testing phase during software development. One of the most interesting methods is to evaluate software reliability by using test data observed in the error‐detection process. In this paper we model the error‐detection process as a stochastic model and introduce several effective measures to evaluate software reliability. In modeling we use the number of test run trials as a unit of the error‐detection period and assume that the cumulative number of software errors detected in an arbitrary testing time interval is a nonhomogeneous Poisson process. Further, we consider the difficulty of error detection because the reliability of software is evaluated from the characteristics and frequency of the errors. Applying the model to the actual test data, we perform the goodness‐of‐fit test and infer the software reliability measures. Finally, we discuss an optimum software release problem based on the software reliability index.