Degeneration of ALF D_n Metrics

Beginning with the Legendre transform construction of hyperk\"ahler metrics, we analyze the ALF version of the D_n metrics. We determine the constraint equation obtained from extremizing the $w$ coordinate of the generating function F(z,\bar{z},u,\bar{u},w) and study its behavior as we send two of the mass parameters of the $D_n$ metric to zero. We find that the constraint equation enforces the limit that the metric becomes that of multi-Taub-NUT.Comment: 14 pages, 7 figures, LaTeX, minor corrections, to appear in JHE

Aggregate real wages: macro fluctuations and micro drivers

Using data from the Current Population Survey from 1980 through 2010 we examine what drives variation and cyclicality in the growth rate of real wages over time. We employ a novel decomposition technique that allows us to divide the time series for median weekly earnings growth into the part associated with the wage growth of persons employed at the beginning and end of the period (the wage growth effect) and the part associated with changes in the composition of earners (the composition effect). The relative importance of these two effects varies widely over the business cycle. When the labor market is tight job switchers get high wage increases, making them account for half of the variation in median weekly earnings growth over our sample. Their wage growth, as well as that of job-stayers, is procyclical. During labor market downturns, this procyclicality is largely offset by the change in the composition of the workforce, leading aggregate real wages to be almost noncyclical. Most of this composition effect works through the part-time employment margin. Remarkably, the unemployment margin neither accounts for much of the variation nor for much of the cyclicality of median weekly earnings growth.Wages ; Labor market

Partial swing golf shots: scaled from full swing or independent technique?

During practice and competition, golfers are required to use submaximal effort to hit the ball a given distance, i.e. perform a partial shot. While the full golf swing has undergone extensive research, little has addressed partial shots and the biomechanical modifications golfers employ. This study investigates the biomechanical changes between full and partial swings, and determines if the partial swing is a scaled version of the full swing. Using a repeated measures design, thirteen male golfers completed a minimum of 10 swings in the full and partial swing conditions, whilst club, ball, kinematic and kinetic parameters were recorded. Large and statistically significant reductions in body motion (centre of pressure ellipse: 33%, p = 0.004 , d = 2.26), combined with moderate reductions in lateral shift (25.5%, p = 0.004, d = 0.332) and smaller reductions in trunk rotation (arm to vertical at top of backswing: 14.1%, p = 0.002, d = 2.58) indicate golfers favour larger reductions in proximal measures, combined with diminished reductions as variables moved distally. Furthermore, the partial swing was not found to be a scaled version of the full swing implying a new approach to coaching practices might be considered

Optimizing MACD Parameters via Genetic Algorithms for Soybean Futures

To create profits, traders must time the market correctly and enter and exit positions at ideal times. Finding the optimal time to enter the market can be quite daunting. The soybean market can be volatile and complex. Weather, sentiment, supply, and demand can all affect the price of soybeans. Traders typically use either fundamental analysis or technical analysis to predict the market for soybean futures\u27 contracts. Every agricultural future\u27s contract or security contract is different in its nature, volatility, and structure. Therefore, the purpose of this research is to optimize the moving average convergence divergence parameter values from traditionally used integers, to values that optimize the profit of the soybean market

Convergent validity of ratings of perceived exertion during resistance exercise in healthy participants: A systematic review and meta-analysis

Background: The validity of ratings of perceived exertion (RPE) during aerobic training is well established; however, it’s validity during resistance exercise is less clear. This meta-analysis used the known relationships between RPE and exercise intensity (EI), heart rate (HR), blood lactate (BLa), blood pressure (BP) and electromyography (EMG) to determine the convergent validity of RPE as a measure of resistance exercise intensity and physiological exertion, during different forms of resistance exercise. Additionally, this study aims to assess the effect of several moderator variables on the strength of the validity coefficients, so that clearer guidance can be given on the use of RPE during resistance exercise. Methods: An online search of 4 databases and websites (PubMed, Web of science, SPORT Discus and Research Gate) was conducted up to 28 February 2020. Additionally, the reference lists of the included articles were inspected manually for further unidentified studies. The inclusion criteria were; healthy participants of any age, a rating scale used to measure RPE, resistance exercise of any type, one cohort receiving no other intervention, and must present data from one of the following outcome measures: EI, HR, BP, EMG or BLa. Weighted mean effect sizes (r) were calculated using a random-effects model. Heterogeneity was assessed using the Tau2 and I2 statistics. Moderator analysis was conducted using random-effects meta-regression. Results: One-hundred and eighteen studies were included in the qualitative synthesis, with 75 studies (99 unique cohorts) included in the meta-analysis. The overall weighted mean validity coefficient was large (0.88; 95% CI 0.84 to 0.91) and between studies heterogeneity was very large (Tau2 = 0.526, I2 = 96.1%). Studies using greater workload ranges, isometric muscle actions, and those that manipulated workload or repetition time, showed the highest validity coefficients. Conversely, sex, age, training status, RPE scale used, and outcome measure did not have an effect. Conclusions: RPE provides a valid measure of exercise intensity and physiological exertion during resistance exercise, with effect sizes comparable or greater than those shown during aerobic exercise. Therefore, RPE may provide an easily accessible means of prescribing and monitoring resistance exercise training. Registration: The systematic review protocol was registered on the PROSPERO database (CRD42018102640)

Doping of inorganic materials in microreactors – preparation of Zn doped Fe₃O₄ nanoparticles

Microreactor systems are now used more and more for the continuous production of metal nanoparticles and metal oxide nanoparticles owing to the controllability of the particle size, an important property in many applications. Here, for the first time, we used microreactors to prepare metal oxide nanoparticles with controlled and varying metal stoichiometry. We prepared and characterised Zn-substituted Fe₃O₄ nanoparticles with linear increase of Zn content (ZnxFe₃−xO₄ with 0 ≤ x ≤ 0.48), which causes linear increases in properties such as the saturation magnetization, relative to pure Fe₃O₄. The methodology is simple and low cost and has great potential to be adapted to the targeted doping of a vast array of other inorganic materials, allowing greater control on the chemical stoichiometry for nanoparticles prepared in microreactors

A comparison of four different approaches to measuring health utility in depressed patients.

BACKGROUND: A variety of instruments are used to measure health related quality of life. Few data exist on the performance and agreement of different instruments in a depressed population. The aim of this study was to investigate agreement between, and suitability of, the EQ-5D-3L, EQ-5D Visual Analogue Scale (EQ-5D VAS), SF-6D and SF-12 new algorithm for measuring health utility in depressed patients. METHODS: The intraclass correlation coefficient (ICC) and Bland and Altman approaches were used to assess agreement. Instrument sensitivity was analysed by: (1) plotting utility scores for the instruments against one another; (2) correlating utility scores and depressive symptoms (Beck Depression Inventory (BDI)); and (3) using Tukey's procedure. Receiver Operating Characteristic (ROC) analysis assessed instrument responsiveness to change. Acceptability was assessed by comparing instrument completion rates. RESULTS: The overall ICC was 0.57. Bland and Altman plots showed wide limits of agreement for each pair wise comparison, except between the SF-6D and SF-12 new algorithm. Plots of utility scores displayed 'ceiling effects' in the EQ-5D-3L index and 'floor effects' in the SF-6D and SF-12 new algorithm. All instruments showed a negative monotonic relationship with BDI, but the EQ-5D-3L index and EQ-5D VAS could not differentiate between depression severity sub-groups. The SF-based instruments were better able to detect changes in health state over time. There was no difference in completion rates of the four instruments. CONCLUSIONS: There was a lack of agreement between utility scores generated by the different instruments. According to the criteria of sensitivity, responsiveness and acceptability that we applied, the SF-6D and SF-12 may be more suitable for the measurement of health related utility in a depressed population than the EQ-5D-3L, which is the instrument currently recommended by NICE.The CoBalT study was funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA) programme (project number: 06/ 404/02)

Cardiac autonomic and left ventricular mechanics following high intensity interval training: a randomised cross-over controlled study.

Physical inactivity and sedentary behaviour is associated with increased cardiovascular disease risk. Short duration high intensity interval training (HIIT) has been shown to improve important health parameters. The aim of the present study was to assess the combined adaptations of the cardiac autonomic nervous system and myocardial functional and mechanical parameters to HIIT. Forty physically inactive and highly sedentary males completed 2-weeks of HIIT and control period. The HIIT protocol consisted of 3x30-second maximal cycle ergometer sprints against a resistance of 7.5% body weight, interspersed with 2-minutes of active recovery. Total power spectral density (PSD) and associated low-frequency (LF) and high-frequency (HF) power spectral components of heart rate variability were recorded. Conventional and speckle tracking echocardiography recorded left ventricular (LV) structural, functional and mechanical parameters. HIIT produced a significant increase in total ln PSD and ln HF, and significant decrease in LF/HF ratio (all p<0.05) compared to the control period. HIIT produced significant improvements in LV diastolic function, including lateral E’, estimated filling pressure (E/E’ ratio), E deceleration time, and isovolumetric relaxation time (p<0.05 for all). Fractional shortening was the only conventional marker of LV systolic function to significantly improve (p<0.05). In this setting, there were significant improvements in global peak systolic strain rate, early and late diastolic strain rate and early to late diastolic strain rate ratio, as well as apical rotation, apical systolic and diastolic rotation velocity, apical radial and circumferential strain and strain rate, LV torsion and LV systolic and diastolic torsion velocity (all p<0.05). A short-term programme of HIIT was associated with a significant increase in cardiac autonomic modulation, demonstrated by a residual increase in cardiac vagal activity as well as significantly improved cardiac function and mechanics. This study demonstrates that HIIT may be an important stimulus to reduce the health implications associated with physical inactivity and sedentary behaviour

Relationship between nutritional status and treatment-related neutropenia in children with nephroblastoma

Background: Assessment of nutritional status of paediatric oncology patients is crucial, as it may influence treatment and clinical outcomes. Concurrent malnutrition and cancer in children may lead to reduced chemotherapy delivery due to impaired tolerance and increased toxicity. Aim: This study aimed to determine the relationship between nutritional status and the prevalence, frequency and duration of treatment-related neutropenia in a cohort of South African children with nephroblastoma. Methods: Seventy-seven children between the ages of 1 and 12 years diagnosed with nephroblastoma at Inkosi Albert Luthuli Central Hospital (IALCH), Durban, between 2004 and 2012, were studied prospectively. Nutritional status was assessed using weight, height, mid-upper arm circumference (MUAC), triceps skinfold thickness (TSFT) and serum albumin. The administration of filgastrim (Neupogen®) was used as a surrogate for neutropenia and the frequency and duration of its use was recorded. Results: There was a significant relationship between the prevalence of treatment-induced neutropenia and malnutrition defined by MUAC. The mean frequency and duration of neutropenia was significantly higher in those classified as malnourished using MUAC. There was a positive correlation between frequency and duration of neutropenia. Conclusions: Malnutrition was prevalent among children with nephroblastoma. The prevalence of treatment-induced neutropenia was higher in those with poor nutritional status, identified by MUAC. Poor nutritional status according to MUAC was also linked to an increased frequency and duration of neutropenia. It is important to include MUAC in the nutritional assessment of children with nephroblastoma

Uber

Uber focuses primarily on the ride-hailing industry, which puts the company in direct competition with regular taxis. The company is like a lot of tech-driven, fast growing entrepreneurial firms in that it still struggles for profitability. Also, the popularity of this new form of transportation has put the company and its close competitors, such as Lyft, in the spotlight of government lawmakers and regulators. If they classify Uber drivers as employees rather than independent contractors, it could dramatically alter the Uber business model. This case is written in the aftermath of the ouster of one of the company’s co-founders as CEO, a not-so-successful initial public offering (IPO), and some very serious human resources issues associated with widely publicized instances of sexual harassment and mistreatment of drivers