bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of High-Intensity Interval Training vs. On-Court Tennis Training in Young Tennis Players
Authors: Kilit Bulent , Arslan Ersan 
Published: August 2018

Abstract
Kilit, B and Arslan, E. Effects of high-intensity interval training vs. on-court tennis training in young tennis players. J Strength Cond Res 33(1): 188–196, 2019—This study aimed to examine the effects of 6 weeks of high-intensity interval training (HIIT) vs. 6 weeks of on-court tennis training (OTT) on the psychophysiological responses, performance responses, and technical scores of young tennis players. Twenty-nine young male tennis players (aged 13.8 ± 0.4 years) were divided into HIIT (n = 14) and OTT groups (n = 15). Both groups trained for the same total training duration with passive rest in each session. Pre-test and post-test included maximum oxygen consumption (

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max), sprinting, jumping, 400-m running time, a tennis-specific technical test, and the t-drill agility test. The training interventions resulted in similar improvements in

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max responses (HIIT: +5.2%, d = 1.36 [large effect]; OTT: +5.5%, d = 1.50 [large effect]). Both training protocols increased jumping and sprinting performances significantly from pre-testing to post-testing (p < 0.05, d values ranging from 0.40 to 1.10). The OTT group showed significantly higher performance responses in terms of the agility test performance and technical scores (p < 0.05, d = ranging from 0.77 to 0.88 [moderate effect]) compared with the HIIT group. By contrast, the HIIT group exhibited significantly higher performance responses in terms of the 400-m running time (p < 0.05, d = 1.32 [large effect]). Our results showed that tennis-specific on-court drills might be a more effective training strategy to improve agility and technical ability with greater physical enjoyment, whereas HIIT may be more appropriate for speed-based conditioning in young tennis players.
Practical Considerations for Assessing Pulmonary Gas Exchange and Ventilation During Flume Swimming Using the MetaSwim Metabolic Cart
Authors: Lomax Mitch , Mayger Billy , Saynor Zoe L. , Vine Christopher , Massey Heather C. 
Published: August 2018

Abstract
Lomax, M, Mayger, B, Saynor, ZL, Vine, C, and Massey, HC. Practical considerations for assessing pulmonary gas exchange and ventilation during flume swimming using the MetaSwim metabolic cart. J Strength Cond Res 33(7): 1941–1953, 2019—The MetaSwim (MS) metabolic cart can assess pulmonary gas exchange and ventilation in aquatic environments. The aims of this study were: (a) to determine the agreement between minute ventilation (VE), pulmonary oxygen uptake (Vo
2), and carbon dioxide output (Vco
2) using the MS and Douglas bag (DB) methods during flume swimming; and (b) to assess the repeatability of these and other MS-derived parameters. Sixteen trained swimmers completed a combined incremental and supramaximal verification cardiopulmonary swimming test to determine maximal Vo
2, 2 progressive intensity swimming tests during which MS and DB measurements were made (agreement protocol), and 3–4 constant-velocity submaximal swimming tests during which only the MS was used (repeatability protocol). Agreement was determined using limits of agreement (LoA), bias, random error, and 95% confidence intervals with systematic bias assessed using paired samples t-tests. Within-trial and between-trial repeatability were determined using the coefficient of variation (CV) and the repeatability coefficient (CR). Where data were heteroscedastic, LoA and CR were log-transformed, antilogged, and displayed as ratios. MetaSwim underestimated peak Vo
2 and Vco
2 (≤0.39 L·min−1) and VE (9.08 L·min−1), whereas submaximal values varied between 2 and 5% for CV and ±1.09–1.22 for ratio CR. The test-retest CV during constant-velocity swimming for VE, tidal volume, breathing frequency, Vo
2, Vco
2, and end-tidal pressures of O2 and CO2 was <9% (ratio CR of ±1.09–1.34). Thus, the MS and DB cannot be used interchangeably. Whether the MS is suitable for evaluating ventilatory and pulmonary responses in swimming will depend on the size of effect required.
Empirical Insights on the Trading Behavior of the UK Leveraged ETFs
Authors: Rompotis Gerasimos G. 
Published: August 2018

Objective. This paper focuses on UK leveraged Exchange Traded Funds (ETFs) and examines their ability to meet their daily targets, the impact of volatility on targets’ achievement, and their pricing efficiency.Methodology. Standard regression analysis is used to evaluate performance, tracking efficiency and persistence in tracking failures, and the relationship between tracking efficiency and market volatility. Moreover, the pricing efficiency is examined along with the persistence in premium and the influence of market factors on premium.Findings. Results reveal that ETFs achieve their targets but occasionally tracking error can be significant. Furthermore, increases in market volatility relate to higher and lower tracking errors for bull and bear ETFs respectively. Moreover, average premiums testify a sufficient fit between trading prices and net asset values whereas the premiums are eliminated sharply. Moreover, the pricing efficiency of bear ETFs is positively associated with benchmark returns. The opposite is the case for bull ETFs. Finally, the pricing deviations are positively related to benchmarks’ volatility.Limitations. A possible limitation is that our sample includes just nine bear and sixteen bull ETFs even though more than 90 leveraged ETFs are traded on the UK market and our results may not be indicative of the entire UK leveraged ETF market. However, we had to use a small sample of ETFs because the trading activity of the rest ETFs has been very poor and, consequently, our analysis could have been biased by a thin trading effect. Originality/Value. This is the first study to examine the UK market of leveraged ETFs.
Application of System Dynamics to Integrate Pavement Preservation in Flexible Pavement Design Process
Authors: Ramachandra Chethana , Ramachandran Sakthivelan , Veeraragavan A. 
Published: August 2018

Abstract
The performance of a pavement depends on factors like the characteristics of the materials in different pavement layers, traffic, climates, environments, construction quality, etc. Though a pavement is designed for 15 years, conventionally, the pavement reaches the threshold level of performance before the design life, warranting minor and major rehabilitation treatments because of factors beyond the control of the designer. However, the maintenance and rehabilitation treatments during the design life of a pavement are not considered in the design process. The performance of a pavement is defined in terms of the various distresses, i.e., cracking, rutting, roughness, potholes, etc. The performance of the pavement also depends on the strength properties of different pavement layers and their thicknesses, quality of construction, traffic, climate, etc. The level of influence of these parameters on each of the distresses is different. In this study, the Mechanistic Empirical Pavement Design Guideline design tool AASHTOWare is used to simulate the data for cracking (percentage of bottom up fatigue cracking), rutting (total rutting), and roughness in terms of the International Roughness Index. A sensitivity analysis is carried out to study the influence of the design parameters on the distresses. From the results of AASHTOWare simulations, a relationship is established between design input parameters and distress growth using multiple linear regression. While this model gives the estimate of distress over time with respect to the design parameters, the year at which the first preservation activity has to be carried out is to be determined. Considering the pavement as a system, the system dynamics concept could be well suited to study the influence of various factors on the performance of the pavement. A system dynamic model is formulated and implemented using system dynamic software POWERSIM. This study identifies the optimal intervention year for the pavement preservation strategies that depend on traffic level, design layer thicknesses, and modulus (strength) of the pavement layers.
A New Approach to Measure Soil Shrinkage Curve
Authors: Li Lin , Zhang Xiong 
Published: August 2018

Abstract
The shrinkage curve is widely used to characterize soil deformation during drying. Over the years, several methods have been developed to measure soil shrinkage curves. However, these methods suffered from several limitations and were rarely used because of difficulties in accurate soil volume measurement during drying. In this study, a simple method is proposed to measure soil shrinkage curves. The soil volume is measured using a photogrammetric technique from which a three-dimensional (3D) model of the soil specimen during drying can be accurately reconstructed. The soil volume is calculated based on the reconstructed 3D model. Meanwhile, a digital balance is used to record the soil weight for the back-calculation of soil water content, which will be used for the shrinkage curve construction. The overall volume measurement error was evaluated to be 0.35 % and 0.43 % through tests on aluminum cylinders and a saturated soil, respectively. With the proposed method, a series of tests were performed to measure the shrinkage curves of a soil mixture (i.e., Fairbanks silt and Kaolin at a ratio of 1:1). Results from these shrinkage tests indicate that the proposed method is cost-effective, accurate, and reliable for soil shrinkage curve measurements.
Uncertainty Quantification in Water Retention Characteristic Curve of Fly Ash Using Copulas
Authors: Prakash A. , Hazra B. , Sreedeep S. 
Published: August 2018

AbstractWater retention characteristic curve (WRCC) is a primary input for modeling the unsaturated behavior of geomaterials. The inadequacy of measurement methodologies in capturing the measurable range of the suction of geomaterials along with material variability induce uncertainties in the quantification of WRCC. The goal of this study is to demonstrate the usefulness of copulas for quantifying the uncertainties in WRCC attributed to the aforementioned reasons. Four instruments measuring different ranges of suction of four fly ashes were used to generate 54 combinations of measured data that would represent possible cases of data-induced uncertainties. van Genuchten WRCC equation parameters (a and n) were determined for these combinations. Statistical analysis of the parameters determined from the 54 combinations indicates a negative correlation with each other; therefore, they represent a bivariate random vector. Four commonly used copulas, Gaussian, Frank, Plackett, and No. 16, were utilized to construct the bivariate density function of the parameters, among which the Gaussian copula was found to be the best fit. The impact of the copula-based model developed in this study on two important unsaturated functions, the suction stress characteristic curve (SSCC) and hydraulic conductivity function (HCF) of fly ash, was investigated and found to be significant. The dispersion in SSCC ranges from monotonically increasing to sharp post peak reduction in the suction range of 20–50 kPa. The limiting state of suction required to reach the theoretical minimum permeability was found to vary widely in the range of 300–9,000 kPa. The study shows that a Gaussian copula with lognormal marginals can adequately capture the significant range of uncertainties associated with WRCC.
Effect of Pre-deformation on the Multiaxial Low-Cycle Fatigue Resistance of 2024-T4 Aluminum Alloy
Authors: Chen Y. J. , Zhou J. , Liu C. C. , Wang F. S. 
Published: August 2018

Abstract
The effect of pre-deformation on the fatigue properties of 2024-T4 aluminum alloy is evaluated, including pre-tension of 1, 2, 3, and 4 % as well as pre-torsion of 10°, 20°, 30°, and 40°. Multiaxial low-cycle fatigue (LCF) tests are carried out under a constant amplitude sinusoidal wave loading with a tension-torsion ratio √3 in air at room temperature. The results indicate that the multiaxial LCF life of the specimen reduces with the pre-deformation level. The observed mechanical behavior and associated phenomena are directly linked to microstructure characteristics, such as dislocation density, surface defects, and microcracks. The analysis of mechanism reveals a competition between beneficial effects that are due to hardening and detrimental influences that are due to defects that are caused by the pre-deformation. However, the multiaxial loading makes the detrimental influence more prominent. The typical fracture morphology of multiaxial fatigue can be observed. With the consideration of the effect of pre-deformation on fatigue limit, a modified criterion is developed to predict the multiaxial fatigue life of 2024-T4 aluminum alloy.
Experimental Measurement of Residual Stresses in Cr-Mo-V Steel Restrained Welds with High Thickness
Authors: Maestri N. , Marangoni P. , Pettene D. , Rivolta B. , Gerosa R. 
Published: August 2018

AbstractThis experimental work is focused on the residual stresses induced by multi-pass welding of thick components. Two samples were produced, inspired by the nozzle-vessel geometry, with Submerged Arc Welding buttwelding, performed according to the standard welding procedures employed by Belleli Energy CPE. The components were characterized by different sizes and groove positions. Measurements of residual stresses were carried out by hole drilling according to ASTM E837-13a, Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method, in different positions of the samples. The measurements were performed on welded, and Dehydrogenation Heat Treatment (350°C, 4h), and Intermediate Stress Relieving treatments. The obtained results allowed a discussion of the influence of the component size on the residual stresses and the effectiveness of an intermediate heat treatment for reducing the stress state.
Novel Pack Cementations: Alternating Current Field Enhanced Pack Cementations
Authors: Xie Fei , Xu Shaoqiang , Pan Jianwei 
Published: August 2018

Abstract
Thermal chemical treatments can effectively improve the surface properties of steels to resist wear, erosion, fretting, and oxidation. Among the various types of thermo-chemical treatment, pack cementation is most often employed for diffusing boron, aluminum, chromium, or silicon into the surface of steel. Pack cementation is superior to other thermo-chemical treatments in process simplicity and flexibility. However, like many other thermo-chemical treatments, conventional pack cementation (CPC) has the disadvantages of a high processing temperature and a long processing duration for obtaining a thick case. A novel approach is presented to enhance pack cementations by applying an alternating current field (ACF) on specimens and pack media. An adjustable 50 Hz alternating current power source was connected to a pair of parallel electrodes set in pack media. Investigations were conducted into the influences of the ACF on pack boriding, aluminizing, chromizing, and silicon-aluminizing. Cases’ thicknesses, structures, phases, hardness distributions, and oxidation resistances were characterized with optical microscopy, X-ray diffraction, Vickers’ hardness testing, and oxidation testing. These treatments can be carried out effectively at temperatures much lower than temperatures for CPC. The ACF can optimize cases’ structures and phases as well as accelerate cases’ growth. Brittle phases, such as iron boride and Al5Fe2, formed on a steel surface by CPC can be easily and economically avoided. The new technology can endow steels with properties that are much better than those provided by CPC. It is suggested that the ACF can enhance chemical reactions among pack agents by heating pack media and intensifying vibrations of active species. The formation, activity, and diffusion of active species containing required elements are promoted. The electromagnetic effect and the heating effect of the ACF increase vacancy concentrations in specimens, which greatly enhance diffusion in treated specimens.
Active Sound Localization Sharpens Spatial Tuning in Human Primary Auditory Cortex
Authors: van der Heijden Kiki , Rauschecker Josef P. , Formisano Elia , Valente Giancarlo , de Gelder Beatrice 
Published: August 2018

Spatial hearing sensitivity in humans is dynamic and task-dependent, but the mechanisms in human auditory cortex that enable dynamic sound location encoding remain unclear. Using functional magnetic resonance imaging (fMRI), we assessed how active behavior affects encoding of sound location (azimuth) in primary auditory cortical areas and planum temporale (PT). According to the hierarchical model of auditory processing and cortical functional specialization, PT is implicated in sound location (“where”) processing. Yet, our results show that spatial tuning profiles in primary auditory cortical areas (left primary core and right caudo-medial belt) sharpened during a sound localization (“where”) task compared with a sound identification (“what”) task. In contrast, spatial tuning in PT was sharp but did not vary with task performance. We further applied a population pattern decoder to the measured fMRI activity patterns, which confirmed the task-dependent effects in the left core: sound location estimates from fMRI patterns measured during active sound localization were most accurate. In PT, decoding accuracy was not modulated by task performance. These results indicate that changes of population activity in human primary auditory areas reflect dynamic and task-dependent processing of sound location. As such, our findings suggest that the hierarchical model of auditory processing may need to be revised to include an interaction between primary and functionally specialized areas depending on behavioral requirements.SIGNIFICANCE STATEMENTAccording to a purely hierarchical view, cortical auditory processing consists of a series of analysis stages from sensory (acoustic) processing in primary auditory cortex to specialized processing in higher-order areas. Posterior-dorsal cortical auditory areas, planum temporale (PT) in humans, are considered to be functionally specialized for spatial processing. However, this model is based mostly on passive listening studies. Our results provide compelling evidence that active behavior (sound localization) sharpens spatial selectivity in primary auditory cortex, whereas spatial tuning in functionally specialized areas (PT) is narrow but task-invariant. These findings suggest that the hierarchical view of cortical functional specialization needs to be extended: our data indicate that active behavior involves feedback projections from higher-order regions to primary auditory cortex.
Altered Auditory Processing, Filtering, and Reactivity in theCntnap2Knock-Out Rat Model for Neurodevelopmental Disorders
Authors: Scott Kaela E. , Schormans Ashley L. , Pacoli Katharine Y. , De Oliveira Cleusa , Allman Brian L. , Schmid Susanne 
Published: August 2018

Sensory processing, and auditory processing in particular, is altered in individuals with neurodevelopmental disorders such as autism spectrum disorders (ASDs). The typical maturation of the auditory system is perturbed in these individuals during early development, which may underlie altered auditory reactivity that persists in later life. Of the many genes that regulate the auditory system development, loss-of-function mutations in theCNTNAP2gene are strongly associated with language processing deficits and ASD. Therefore, using a novelCntnap2knock-out rat model, we tested the impact ofCntnap2loss on auditory processing, filtering, and reactivity throughout development and young adulthood in male and female animals. Although hearing thresholds were not altered inCntnap2knock-out animals, we found a reduction in response amplitudes and a delay in response latency of the auditory brainstem response (ABR) in juvenileCntnap2knock-out rats compared with age-matched controls. Amplitudes and latency of the ABR largely normalized by adulthood, indicating a delayed maturation of auditory processing pathways inCntnap2knock-out rats. Despite the reduced ABR amplitudes, adolescentCntnap2knock-out animals displayed increased startle reactivity accompanied by disruptions in sensory filtering and sensorimotor gating across various conditions, most of which persisted in adulthood. All of these observations show striking parallels to disruptions reported in ASD. Our results also imply that developmental disruptions of sensory signal processing are associated with persistent changes in neural circuitries responsible for implicit auditory evoked behavior, emphasizing the need for interventions that target sensory processing disruptions early during development in ASD.SIGNIFICANCE STATEMENTThis is the first study of brainstem auditory processing in a novel knock-out rat model with very high construct and face validity for autism spectrum disorders. Electrophysiological and behavioral measures of implicit auditory-evoked responses were systematically taken across developmental stages. Auditory processing, filtering, and reactivity disruptions show striking similarities to observations in autism. We also show for the first time that, whereas auditory brainstem responses normalize by adulthood, disruptions in brainstem-mediated auditory-evoked behavior persist. This indicates that early developmental perturbations in sensory processing can cause permanent maladaptive changes in circuitries responsible for auditory reactivity, underlining the importance for interventions early during development aiming at normalizing sensory processing.