Grey Relational Analysis of Lower Limb Muscle Fatigue and Pedalling Performance Decline of Elite Athletes during a 30-Second All-Out Sprint Cycling Exercise

The 30-second all-out sprint cycling exercise is a classical sport capacity evaluation method, which may cause severe lower limb muscle fatigue. However, the relationship between lower limb muscle fatigue and the decline in exercise performance during 30-second sprint cycling remains unclear. In this study, ten cyclists volunteered to participate in a 30-second all-out sprint cycling while power, cadence, and surface electromyographic (EMG) signals of eight lower limb muscles were recorded during the exercise. EMG mean frequency (MNF) of each lower limb muscle group was computed for every 3-second epoch based on wavelet packet transformation. Grey relational grades between pedalling performance and the EMG MNF of each lower limb muscle group during the whole process were calculated. The results demonstrated that EMG MNF of the rectus femoris (RF), vastus (VAS), gastrocnemius (GAS), and tibialis anterior (TA) progressively tired during a 30-second all-out sprint cycling exercise. Of the muscles evaluated, the degree of fatigue of TA showed the greatest association with exercise performance decline, whereas the muscle fatigue of RF, VAS, and GAS also significantly impacted exercise performance during a 30-second all-out sprint cycling exercise.

Research on a reference signal optimisation algorithm for indoor Bluetooth positioning

GPS has a sharp performance decline in terms of accuracy indoors due to the complex building structure. A combined algorithm, targeting at received signal strength indication (RSSI) calibration optimisation, depending on deep neural network training via input vector Γ and the target output vector Ψ, termed reference signal optimisation algorithm (RSOA) is proposed to improve the positioning accuracy in the indoor Bluetooth positioning networks. Experimental results show that the relative error of the proposed RSOA between the estimated results and the measured ones can reach as low as 0.2%, and the absolute errors can be reduced to 0.13 m at most within 10 m.

Research on Topology and Control System of High Power Grid Simulator

Grid simulator can simulate the output of various types of power grid failure to test wind power grid-side equipment, in the design of high-power grid simulator, due to the switching frequency restrictions, will affect the control bandwidth, resulting in the power grid simulator system performance decline. Therefore, the modular multi-level converter (MMC) with higher equivalent switching frequency is used on the inverter side of the grid simulator, and the bridge arm circulation suppression strategy based on the second-order generalized integrator (SOGI) and vector scale integral (VPI) resonant controller is proposed for the internal bridge arm circulation of the converter. Finally, based on RT-LAB, the network simulator controller hardware in the ring (CHIL) experimental platform is built and experimented, the experimental results show that the design of high-power power grid simulator system can simulate the output to obtain the required grid failure.

Efficiency or Innovation? The Long-Run Payoff of Cloud Computing

Considering the mixed arguments and uncertainty about the payoff of cloud computing, this paper empirically studies the long-term cloud computing impact on the financial performance, specifically from the perspective of efficiency and innovation. Taking 253 pairs of listed companies in China as the research sample, propensity score matching and difference in differences techniques combined with OLS regression are conducted to analyze a rolling 5-year panel data. The analysis results show that cloud computing adoption leads to years of financial performance decline followed by an upturn. The downward trend is more pronounced when it is adopted with innovation. This paper contributes to the existing literatures by leveraging archival performance data to verify the long-term business value and revealing the value realization difference between efficiency- and innovation-oriented cloud computing adoptions. The findings remind the managers to see the two sides of cloud computing and make rational adoption decisions, especially cloud-based innovation, according to their actual situations.

Analysis of the Impact of Leadership Determination on Employee Performance at PT BTN (Persero), Tbk Medan Sharia Branch Office

Not achieving the Key Performance Index (KPI) target within 5 consecutive years can be used as an indicator of the lack of maximum management in the company in facing competition. In-depth considerations are needed to answer the problems that occur related to this performance decline. Referring to several studies conducted related to motivation and performance, it is known that many variables can affect performance. The purpose of this study was to determine and analyze the influence of transformational, democratic and situational leadership styles on employee performance at PT Bank Tabungan Negara (Persero), Tbk Sharia Medan Branch Office. The population in this study were all employees who worked at PT Bank Tabungan Negara (Persero), Tbk Sharia Medan Branch Office. Many samples in this study were as many as 50 respondents. Data were collected using observations and questionnaires. The data is tested using validity and reliability tests, and the data must meet the elements of the classical assumption test. Furthermore, the data analysis test was carried out using multiple regression analysis; t test, F test, and the coefficient of determination.The results of this study indicate that there is a significant influence on the transformational, democratic and situational leadership style either partially or simultaneously. The amount of Transformational Leadership, Democratic Leadership and Situational Leadership explains that employee performance is 0.689 or equal to 68.90% while the remaining 31.10% is explained by other variables. Keywords: Transformational, Democratic, Situational, Performance Leadership.

Mediterranean Diet and Physical Activity for Successful Aging: An Update for Nutritionists and Endocrinologists

The constant advancement in the medical field has allowed for the diagnosis and treatment of several health conditions. It has also contributed to increasing the average human lifespan, which is considered an outstanding achievement in history. Nevertheless, the impact of this in an ever-increasing aged population with chronic diseases and, most of the time, with limited and poor quality of life was not considered. Thus, it is imperative to establish strategies to age successfully. In order to do have a better understanding of this crucial issue, this review will analyze the endocrine changes in the elderly. It will present common conditions found in this population, chronic inflammation, and oxidative stress. Additionally, we will explain aging-related metabolic and physical performance decline related to hormone changes and lifestyle modifications. We will propose the Mediterranean diet and some specific guidelines about physical activity as part of the plan to have an active and successful aging process.

Acceleration of Longitudinal Track and Field Performance Declines in Athletes Who Still Compete at the Age of 100 Years

While physical performance decline rates accelerate after around the age of 70 years, longitudinal athletic performance trends in athletes older than 95 years are unknown. We hypothesized a further accelerated decline in human performance in athletes who still perform at the age of 100 years. To investigate this, longitudinal data of all athletes with results at or over the age of 100 years were collected from the “World Master Rankings” data base spanning 2006–2019 (138 results from 42 athletes; 5 women, 37 men; maximum 105 years) and compared to previously published longitudinal data from 80- to 96-year-old athletes from Sweden (1,134 results from 374 athletes). Regression statistics were used to compare performance decline rates between disciplines and age groups. On average, the individual decline rate of the centenarian group was 2.53 times as steep (100 m: 8.22x; long jump: 0.82x; shot put: 1.61x; discus throw: 1.04x; javelin throw: 0.98x) as that seen in non-centenarians. The steepest increase in decline was found in the 100-m sprint (t-test: p < 0.05, no sign. difference in the other disciplines). The pooled regression statistics of the centenarians are: 100 m: R = 0.57, p = 0.004; long jump: R = 0.90, p < 0.001; shot put: R = 0.65, p < 0.001; discus throw: R = 0.73, p < 0.001; javelin throw: R = 0.68, p < 0.001. This first longitudinal dataset of performance decline rates of athletes who still compete at 100 years and older in five athletics disciplines shows that there is no performance plateau after the age of 90, but rather a further acceleration of the performance decline.

Anodal tDCS augments and preserves working memory beyond time-on-task deficits

Transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPFC) has been shown to promote working memory (WM), however, its efficacy against time-on-task-related performance decline and associated cognitive fatigue remains uncertain. This study examined the impact of anodal tDCS of the left DLPFC on performance during a fatiguing visuospatial WM test. We adopted a repeated measures design, where 32 healthy adults (16 female), underwent anodal, control and sham tDCS on separate days. They completed an hour long two-back test, with stimulation intensity, onset, and duration set at 1 mA, at the 20th minute for 10 minutes respectively. Task performance, subjective responses, and heart rate variability (HRV) were captured during the experiment. Anodal tDCS substantially improved WM relative to sham tDCS and control in both sexes. These benefits lasted beyond the stimulation interval, and were unique across performance measures. However, no perceptual changes in subjective effort or fatigue levels were noted between conditions, although participants reported greater discomfort during stimulation. While mood and sleepiness changed with time-on-task, reflecting fatigue, these were largely similar across conditions. HRV increased under anodal tDCS and control, and plateaued under sham tDCS. We found that short duration anodal tDCS at 1 mA was an effective countermeasure to time-on-task deficits during a visuospatial two-back task, with enhancement and preservation of WM capacity. However, these improvements were not available at a perceptual level. Therefore, wider investigations are necessary to determine “how” such solutions will be operationalized in the field, especially within human-centered systems.