Peak wavelength shifts and opponent color theory

NASA Astrophysics Data System (ADS)

Ashdown, Ian; Salsbury, Marc

2007-09-01

We adapt the tenets of Hering's opponent color theory to the processing of data obtained from a tristimulus colorimeter to independently determine the intensity and possible peak wavelength shift of a narrowband LED. This information may then be used for example in an optical feedback loop to maintain constant intensity and chromaticity for a light source consisting of two LEDs with different peak wavelengths. This approach is particularly useful for LED backlighting of LCD display panels using red, green, and blue LEDs, wherein a tristimulus colorimeter can be used to maintain primary chromaticities to within broadcast standard limits in real time.

Hierarchically porous carbon/polyaniline hybrid for use in supercapacitors.

PubMed

Joo, Min Jae; Yun, Young Soo; Jin, Hyoung-Joon

2014-12-01

A hierarchically porous carbon (HPC)/polyaniline (PANI) hybrid electrode was prepared by the polymerization of PANI on the surface of the HPC via rapid-mixing polymerization. The surface morphologies and chemical composition of the HPC/PANI hybrid electrode were characterized using transmission electron microscopy and X-ray photoelectron spectroscopy (XPS), respectively. The surface morphologies and XPS results for the HPC, PANI and HPC/PANI hybrids indicate that PANI is coated on the surface of HPC in the HPC/PANI hybrids which have two different nitrogen groups as a benzenoid amine (-NH-) peak and positively charged nitrogen (N+) peak. The electrochemical performances of the HPC/PANI hybrids were analyzed by performing cyclic voltammetry and galvanostatic charge-discharge tests. The HPC/PANI hybrids showed a better specific capacitance (222 F/g) than HPC (111 F/g) because of effect of pseudocapacitor behavior. In addition, good cycle stabilities were maintained over 1000 cycles.

Strength and coordination training are both effective in reducing the postural tremor amplitude of older adults.

PubMed

Keogh, Justin W L; Morrison, Steve; Barrett, Rod

2010-01-01

The current study investigated the effect of 2 different types of unilateral resistance training on the postural tremor output of 19 neurologically healthy men age 70-80 yr. The strength- (n = 7) and coordination-training (n = 7) groups trained twice a week for 6 wk, performing dumbbell biceps curls, wrist flexions, and wrist extensions, while the control group (n = 5) maintained their normal activities. Changes in index-finger tremor (RMS amplitude, peak, and proportional power) and upper limb muscle coactivation were assessed during 4 postural conditions that were performed separately with the trained and untrained limbs. The 2 training groups experienced significantly greater reductions in mean RMS tremor amplitude, peak, and proportional tremor power 8-12 Hz and upper limb muscle coactivation, as well as greater increases in strength, than the control group. These results further demonstrate the benefits of resistance training for improving function in older adults.

Upright exercise or supine lower body negative pressure exercise maintains exercise responses after bed rest

NASA Technical Reports Server (NTRS)

Lee, S. M.; Bennett, B. S.; Hargens, A. R.; Watenpaugh, D. E.; Ballard, R. E.; Murthy, G.; Ford, S. R.; Fortney, S. M.

1997-01-01

Adaptation to bed rest or space flight is accompanied by an impaired ability to exercise in an upright position. We hypothesized that a daily, 30-min bout of intense, interval exercise in upright posture or supine against lower body negative pressure (LBNP) would maintain upright exercise heart rate and respiratory responses after bed rest. Twenty-four men (31 +/- 3 yr) underwent 5 d of 6 degree head-down tilt: eight performed no exercise (CON), eight performed upright treadmill exercise (UPex), and eight performed supine treadmill exercise against LBNP at -51.3 +/- 0.4 mm Hg (LBNPex). Submaximal treadmill exercise responses (56, 74, and 85% of VO2peak) were measured pre- and post-bed rest. In CON, submaximal heart rate, respiratory exchange ratio, and ventilation were significantly greater (P < or = 0.05) after bed rest. In UPex and LBNPex, submaximal exercise responses were similar pre- and post-bed rest. Our results indicate that a daily 30-min bout of intense, interval upright exercise training or supine exercise training against LBNP is sufficient to maintain upright exercise responses after 5 d of bed rest. These results may have important implications for the development of exercise countermeasures during space flight.

Transcutaneous spinal direct current stimulation induces lasting fatigue resistance and enhances explosive vertical jump performance

PubMed Central

Tate, Rothwelle J.; Conway, Bernard A.

2017-01-01

Transcutaneous spinal direct current stimulation (tsDCS) is a non-invasive neuromodulatory intervention that has been shown to modify excitability in spinal and supraspinal circuits in animals and humans. Our objective in this study was to explore the functional neuromodulatory potential of tsDCS by examining its immediate and lasting effects over the repeated performance of a whole body maximal exercise in healthy volunteers. Using a double-blind, randomized, crossover, sham-controlled design we investigated the effects of 15 min of anodal tsDCS on repeated vertical countermovement jump (VCJ) performance at 0, 20, 60, and 180 minutes post-stimulation. Measurements of peak and take-off velocity, vertical displacement, peak power and work done during countermovement and push-off VCJ phases were derived from changes in vertical ground reaction force (12 performance parameters) in 12 healthy participants. The magnitude and direction of change in VCJ performance from pre- to post-stimulation differed significantly between sham and active tsDCS for 7 of the 12 VCJ performance measures (P < 0.05). These differences comprised of a post-sham fatigue in VCJ displacement/work done, peak to peak power and take-off velocity, and a resilience to this fatigue effect post-active tsDCS. In addition there was also an enhancement of countermovement performance and total work done (P < 0.05). These changes did not vary across repeated VCJ performances over time post-tsDCS (P > 0.05). Our original findings demonstrate that one single session of anodal tsDCS in healthy subjects can prevent fatigue and maintain or enhance different aspects of whole body explosive motor power over repeated sets of VCJs performed over a period of three hours. The observed effects are discussed in relation to alterations in central fatigue mechanisms, muscle contraction mode during jump execution and changes in spinal cord excitability. These findings have important implications for power endurance sport performance and for neuromotor rehabilitation. PMID:28379980

Physiological characteristics of an aging Olympic athlete.

PubMed

Nybo, Lars; Schmidt, Jakob F; Fritzdorf, Stephen; Nordsborg, Nikolai B

2014-11-01

To investigate the physiological basis of continued world-class performance of a world-class rower who won medals (three gold and two bronze) at five consecutive Olympic Games. From the age of 19 to 40 yr, maximal oxygen uptake (VO2 max), peak HR, blood lactate, and rowing ergometer performance were assessed annually. During the first years of his elite career (from age 19 to 24), VO2 max increased from 5.5 to approximately 5.9 L · min(-1) (78 mL · min(-1) · kg(-1)) and his average power during 6-min maximal rowing increased from 420 to approximately 460 W. Although his HRmax declined by approximately 20 bpm during the 20-yr period, maximal aerobic power, evaluated both as VO2 max and 6-min test performance, was maintained until the age of 40. Furthermore, peak lactate levels remained unchanged and average power outputs during 10-s, 60-s, and 60-min ergometer tests were all maintained at approximately 800 W, approximately 700 W, and approximately 350 W, respectively, indicating that he was able to preserve both aerobic and anaerobic exercise performances. Echocardiographic analyses revealed a left ventricular mass of 198 g and left ventricular end-diastolic diameter of 5.8 cm. This longitudinal case indicates that until the age of 40 yr, a steady increase in the oxygen pulse may have compensated for the significant decline in the maximal heart frequency. Furthermore, the maintenance of aerobic and anaerobic exercise capacities allowed this Olympic athlete to compete at the highest level for almost two decades.

The effect of six days of dietary nitrate supplementation on performance in trained CrossFit athletes.

PubMed

Kramer, Samuel J; Baur, Daniel A; Spicer, Maria T; Vukovich, Matthew D; Ormsbee, Michael J

2016-01-01

While it is well established that dietary nitrate reduces the metabolic cost of exercise, recent evidence suggests this effect is maintained 24 h following the final nitrate dose when plasma nitrite levels have returned to baseline. In addition, acute dietary nitrate was recently reported to enhance peak power production. Our purpose was to examine whether chronic dietary nitrate supplementation enhanced peak power 24 h following the final dose and if this impacted performance in a heavily power-dependent sport. In a double-blind, randomized, crossover design, maximal aerobic capacity, body composition, strength, maximal power (30 s Wingate), endurance (2 km rowing time trial), and CrossFit performance (Grace protocol) were assessed before and after six days of supplementation with nitrate (NO) (8 mmol·potassium nitrate·d -1 ) or a non-caloric placebo (PL). A 10-day washout period divided treatment conditions. Paired t -tests were utilized to assess changes over time and to compare changes between treatments. Peak Wingate power increased significantly over time with NO (889.17 ± 179.69 W to 948.08 ± 186.80 W; p  = 0.01) but not PL (898.08 ± 183.24 W to 905.00 ± 157.23 W; p  = 0.75). However, CrossFit performance was unchanged, and there were no changes in any other performance parameters. Consuming dietary nitrate in the potassium nitrate salt form improved peak power during a Wingate test, but did not improve elements of strength or endurance in male CrossFit athletes.

Using contemporary liquid chromatography theory and technology to improve capillary gradient ion-exchange separations.

PubMed

Wouters, Bert; Broeckhoven, Ken; Wouters, Sam; Bruggink, Cees; Agroskin, Yury; Pohl, Christopher A; Eeltink, Sebastiaan

2014-11-28

The gradient-performance limits of capillary ion chromatography have been assessed at maximum system pressure (34.5 MPa) using capillary columns packed with 4.1 μm macroporous anion-exchange particles coated with 65 nm positively-charged nanobeads. In analogy to the van-Deemter curve, the gradient performance was assessed applying different flow rates, while decreasing the gradient time inversely proportional to the increase in flow rate in order to maintain the same retention properties. The gradient kinetic-performance limits were determined at maximum system pressure, applying tG/t0=5, 10, and 20. In addition, the effect of retention on peak width was assessed in gradient mode for mono-, di-, and trivalent inorganic anions. The peak width of late-eluting ions can be significantly reduced by using concave gradient, resulting in better detection sensitivity. A signal enhancement factor of 8 was measured for a late-eluting ion when applying a concave instead of a linear gradient. For the analysis of a complex anion mixture, a coupled column with a total length of 1.05 m was operated at the kinetic-performance limit applying a linear 250 min gradient (tG/t0=10). The peak capacity varied between 200 and 380 depending on analyte retention, and hence on charge and size of the ion. Copyright © 2014 Elsevier B.V. All rights reserved.

The Borg scale as an important tool of self-monitoring and self-regulation of exercise prescription in heart failure patients during hydrotherapy. A randomized blinded controlled trial.

PubMed

Carvalho, Vitor Oliveira; Bocchi, Edimar Alcides; Guimarães, Guilherme Veiga

2009-10-01

The Borg Scale may be a useful tool for heart failure patients to self-monitor and self-regulate exercise on land or in water (hydrotherapy) by maintaining the heart rate (HR) between the anaerobic threshold and respiratory compensation point. Patients performed a cardiopulmonary exercise test to determine their anaerobic threshold/respiratory compensation points. The percentage of the mean HR during the exercise session in relation to the anaerobic threshold HR (%EHR-AT), in relation to the respiratory compensation point (%EHR-RCP), in relation to the peak HR by the exercise test (%EHR-Peak) and in relation to the maximum predicted HR (%EHR-Predicted) was calculated. Next, patients were randomized into the land or water exercise group. One blinded investigator instructed the patients in each group to exercise at a level between "relatively easy and slightly tiring". The mean HR throughout the 30-min exercise session was recorded. The %EHR-AT and %EHR-predicted did not differ between the land and water exercise groups, but they differed in the %EHR-RCP (95 +/-7 to 86 +/-7, P<0.001) and in the %EHR-Peak (85 +/-8 to 78 +/-9, P=0.007). Exercise guided by the Borg scale maintains the patient's HR between the anaerobic threshold and respiratory compensation point (ie, in the exercise training zone).

Design and demonstration of a storage assisted air conditioning system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avril, F.; Irvine, T.F.

1982-04-01

The report describes the design and demonstration of a storage-assisted air conditioning system for residential central air conditioning applications. The system was designed to reduce peak air conditioning loads by storing coolness to fulfill daytime air conditioning requirements. The system design analyses, as well as performance data obtained from a residential installation on Long Island, are presented, along with an economic evaluation of the system. The results of the study indicate that such a system can reduce air conditioning peak load requirements while maintaining house temperature and humidity within prescribed limits. However, further system optimization is required, as well asmore » either equipment costs reduction or increased incentives, to make this system economically attractive for use in New York State.« less

Age, psychological skills, and golf performance: a prospective investigation.

PubMed

Hayslip, Bert; Petrie, Trent A

2014-03-01

This study explored the influence of age in understanding mental skills utilization in the context of performance at a major national golf competition. Participants, who ranged in age and in skill level, included 1150 male and 170 female amateur golfers competing in the Dupont World Amateur Golf Championship in Myrtle Beach, South Carolina. Measures targeted general mental skills used in competitions, golf-specific skills, and competitive trait anxiety. Hierarchical linear regression was utilized to explore the potential moderating role that chronological age may play in influencing the impact of psychological skills and anxiety on competitive tournament performance across the adult life span. Findings suggested no significant age-moderating effects and instead pointed to the importance of developing golf-specific psychological skills to enhance or maintain performance, irrespective of age. Although automaticity (performance feels "automatic") predicted performance for all golfers, commitment to the game and confidence in one's putting did so only for the men. These findings reinforce the age-irrelevant role of such skills in fostering the experience of peak performance in a competitive sport context and underscore the importance of interventions targeting older players to help maintain or facilitate the use of psychological skills in helping them manage their games.

Coding for parallel execution of hardware-in-the-loop millimeter-wave scene generation models on multicore SIMD processor architectures

NASA Astrophysics Data System (ADS)

Olson, Richard F.

2013-05-01

Rendering of point scatterer based radar scenes for millimeter wave (mmW) seeker tests in real-time hardware-in-the-loop (HWIL) scene generation requires efficient algorithms and vector-friendly computer architectures for complex signal synthesis. New processor technology from Intel implements an extended 256-bit vector SIMD instruction set (AVX, AVX2) in a multi-core CPU design providing peak execution rates of hundreds of GigaFLOPS (GFLOPS) on one chip. Real world mmW scene generation code can approach peak SIMD execution rates only after careful algorithm and source code design. An effective software design will maintain high computing intensity emphasizing register-to-register SIMD arithmetic operations over data movement between CPU caches or off-chip memories. Engineers at the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) applied two basic parallel coding methods to assess new 256-bit SIMD multi-core architectures for mmW scene generation in HWIL. These include use of POSIX threads built on vector library functions and more portable, highlevel parallel code based on compiler technology (e.g. OpenMP pragmas and SIMD autovectorization). Since CPU technology is rapidly advancing toward high processor core counts and TeraFLOPS peak SIMD execution rates, it is imperative that coding methods be identified which produce efficient and maintainable parallel code. This paper describes the algorithms used in point scatterer target model rendering, the parallelization of those algorithms, and the execution performance achieved on an AVX multi-core machine using the two basic parallel coding methods. The paper concludes with estimates for scale-up performance on upcoming multi-core technology.

Center of Pressure Displacement of Standing Posture during Rapid Movements Is Reorganised Due to Experimental Lower Extremity Muscle Pain.

PubMed

Shiozawa, Shinichiro; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

2015-01-01

Postural control during rapid movements may be impaired due to musculoskeletal pain. The purpose of this study was to investigate the effect of experimental knee-related muscle pain on the center of pressure (CoP) displacement in a reaction time task condition. Nine healthy males performed two reaction time tasks (dominant side shoulder flexion and bilateral heel lift) before, during, and after experimental pain induced in the dominant side vastus medialis or the tibialis anterior muscles by hypertonic saline injections. The CoP displacement was extracted from the ipsilateral and contralateral side by two force plates and the net CoP displacement was calculated. Compared with non-painful sessions, tibialis anterior muscle pain during the peak and peak-to-peak displacement for the CoP during anticipatory postural adjustments (APAs) of the shoulder task reduced the peak-to-peak displacement of the net CoP in the medial-lateral direction (P<0.05). Tibialis anterior and vastus medialis muscle pain during shoulder flexion task reduced the anterior-posterior peak-to-peak displacement in the ipsilateral side (P<0.05). The central nervous system in healthy individuals was sufficiently robust in maintaining the APA characteristics during pain, although the displacement of net and ipsilateral CoP in the medial-lateral and anterior-posterior directions during unilateral fast shoulder movement was altered.

A Systems Analysis to Define the Types of Rations Needed to Support Amphibious Operations

DTIC Science & Technology

1985-09-01

Navy and the individual Marine) and in cost. • RATION QUALITY - High Acceptance - Maximize Quality - Minimize Menu Cycle As one of four...maintaining high customer acceptance. Carbohydrate-enhanced A- or B-Ration menus would be provided to embarked (shipboard) Marines for approximately 72...assistance; 2) the typical dietery myth that high protein meals are what will "help me perform at my peak" would be circumvented; the Marine would

Hypervolemia in men from drinking hyperhydration fluids at rest and during exercise

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Looftwilson, R.; Wisherd, P. P.; Fung, P. P.; Ertl, A. C.; Jackson, C. G. R.; Barnes, P. R.; Wong, L. G.

1994-01-01

To test the hypothesis that drink composition is more important than drink osmolality (Osm) for maintaining and increasing plasma volume (PV) at rest and during exercise, six men (22-39 yr, 76.84 +/- 16.19 kg, 2.99 +/- 0.45 L/min VO2 peak) each underwent six treatments while sitting for 90 min (VO2 = 0.39 L/min) and then performed upright ergometer exercise for 70 min (VO2 = 2.08 +/- 0.33 1/min, 70% +/- 7% VO2 peak). Drink formulations (10 ml/kg body weight, X = 768 ml) for the sitting period were: P1 (55 mEq Na(+), 365 mOsm/kg H2O), P2 (97.1 mEq Na(+), 791 mOsm/kg), P2G (113 mEqNa(+), 80 ml glycerol, 1,382 mOsm/kg, HyperAde (HA) (164 mEq Na(+), 253 mOsm/kg), and 01 and 02 (no drinking). The exercise drink (10 ml/kg, 768 ml) was P1 for all treatments except 02. Plasma volume at rest increased (p less than 0.05) by 4.7% with P1 and by 7.9% with HA. Percent change in PV during exercise was +1% to +3%0(NS) with HA; -6% to 0% (NS) with P1, P2, P2G, and 01; and -8% to -5% (p less than 0.05) with 02. HyperAde, with the lowest osmolality (253 mOsm/kg), maintained PV at rest and during exercise, whereas the other drinks with lower Na(+) and higher osmolality (365 to 1,382 mOsm/kg) did not. But Performance 1 also increased PV at rest. Thus, drink composition may be more important than drink osmolality for increasing plasma volume at rest and for maintaining it during exercise.

Physiological plasticity of metabolic rates in the invasive honey bee and an endemic Australian bee species.

PubMed

Tomlinson, Sean; Dixon, Kingsley W; Didham, Raphael K; Bradshaw, S Don

2015-12-01

Seasonal variation in metabolic rate and evaporative water loss as a function of ambient temperature were compared in two species of bees. The endemic blue-banded bee, Amegilla chlorocyanea, is a solitary species that is an important pollinator in the south-west Australian biodiversity hotspot. Responses were compared with the European honeybee, Apis mellifera, naturalised in Western Australia almost 200 years ago. Metabolic rate increased exponentially with temperature to a peak in both species, and then declined rapidly, with unique scaling exponents and peaks for all species-by-season comparisons. Early in the austral summer, Apis was less thermally tolerant than Amegilla, but the positions reversed later in the foraging season. There were also significant exponential increases in evaporative water loss with increasing temperature, and both season and species contributed to significantly different responses. Apis maintained relatively consistent thermal performance of metabolic rate between seasons, but at the expense of increased rates of evaporative water loss later in summer. In contrast, Amegilla had dramatically increased metabolic requirements later in summer, but maintained consistent thermal performance of evaporative water loss. Although both species acclimated to higher thermal tolerance, the physiological strategies underpinning the acclimation differed. These findings may have important implications for understanding the responses of these and other pollinators to changing environments and for their conservation management.

Cutting moments and grip forces in meat cutting operations and the effect of knife sharpness.

PubMed

McGorry, Raymond W; Dowd, Peter C; Dempsey, Patrick G

2003-07-01

The force exposure associated with meat cutting operations and the effect of knife sharpness on performance and productivity have not been well documented. Specialized hardware was used to measure grip force and reactive moments with 15 professional meat cutters performing lamb shoulder boning, beef rib trimming and beef loin trim operations in a field study conducted in two meat packing plants. A system for measuring relative blade sharpness was developed for this study. Mean and peak cutting moments observed for the meat cutting operations, averaged across subjects were 4.7 and 17.2 Nm for the shoulder boning, 3.5 and 12.9 Nm for the rib trim, and 2.3 and 10.6 Nm for the loin trim, respectively. Expressed as percent of MVC, mean grip forces of 28.3% and peak grip forces of 72.6% were observed overall. Blade sharpness was found to effect grip forces, cutting moments and cutting time, with sharper blades requiring statistically significantly lower peak and mean cutting moments, and grip forces than dull knives. Efforts aimed at providing and maintaining sharp blades could have a significant impact on force exposure.

Hyperventilation as a strategy for improved repeated sprint performance.

PubMed

Sakamoto, Akihiro; Naito, Hisashi; Chow, Chin-Moi

2014-04-01

Repeated high-intensity sprints incur substantial anaerobic metabolic challenges and create an acidic muscle milieu that is unfavorable for subsequent performance. Hyperventilation, resulting in respiratory alkalosis, acts as a compensatory mechanism for metabolic acidosis. This study tested the hypothesis that hyperventilation performed during recovery intervals would attenuate performance decrement in repeated sprint pedaling. Thirteen male university athletes performed 10 sets of 10-second maximal pedaling on a cycle ergometer with a 60-second recovery between sets under control (spontaneous breathing) and hyperventilation conditions in a crossover counter-balanced manner. Pedaling load was set at 0.075 × body mass. Peak and mean power outputs were documented for each set to compare performance decrements for 10 sets between conditions. Hyperventilation (60 breaths per minute and end-tidal partial pressure of CO2 maintained at 20-25 mm Hg) was performed 30 seconds before each sprint set. This intervention successfully increased blood pH by 0.03-0.07 but lowered P(CO2) by 1.2-8.4 mm Hg throughout exercise (p < 0.001). The peak and mean power outputs, and blood [La] accumulation were not significantly different between the conditions. However, a significant condition × time interaction existed for peak power (p = 0.035) and mean power (p = 0.023), demonstrating an attenuation in power decrement in later sprint sets with hyperventilation. In conclusion, hyperventilation implemented during recovery intervals of repeated sprint pedaling attenuated performance decrements in later exercise bouts that was associated with substantial metabolic acidosis. The practical implication is that hyperventilation may have a strategic role for enhancing training effectiveness and may give an edge in performance outcomes.

Sex-specific responses to self-paced, high-intensity interval training with variable recovery periods.

PubMed

Laurent, C Matthew; Vervaecke, Lauren S; Kutz, Matthew R; Green, J Matthew

2014-04-01

This study examined sex-specific responses during self-paced, high-intensity interval training (HIIT). Sixteen (8 men and 8 women) individuals completed a peak oxygen uptake test and 3 treadmill HIIT sessions on separate days. The HIIT sessions consisted of six 4-minute intervals performed at the highest self-selected intensity individuals felt they could maintain. Recovery between intervals was counterbalanced and consisted of 1-, 2-, or 4-minute recovery during each trial. Relative measures of intensity, including percentage of velocity at VO2peak (vVO2peak), %VO2peak, %HRmax, and blood lactate concentration ([La]), were observed during the trials. Perceived readiness was recorded immediately before and ratings of perceived exertion (RPE) were recorded at the end of each interval with session RPE recorded after each trial. Results revealed a significant effect of sex on %vVO2peak (p < 0.01) and %HRmax (p < 0.01). Data show that across trials, men self-select higher %vVO2peak (84.5 vs. 80.7%), whereas women produce higher %HRmax (96.9 vs. 92.1%) and %VO2peak (89.6 vs. 86.1%) with no difference in [La] or perceptual responses. These findings support the notion that women may demonstrate improved recovery during high-intensity exercise, as they will self-select intensities resulting in greater cardiovascular strain. Moreover, results confirm previous findings suggesting that a 2:1 work-to-rest ratio is optimal during HIIT for both men and women.

A modified multiscale peak alignment method combined with trilinear decomposition to study the volatile/heat-labile components in Ligusticum chuanxiong Hort - Cyperus rotundus rhizomes by HS-SPME-GC/MS.

PubMed

He, Min; Yan, Pan; Yang, Zhi-Yu; Zhang, Zhi-Min; Yang, Tian-Biao; Hong, Liang

2018-03-15

Head Space/Solid Phase Micro-Extraction (HS-SPME) coupled with Gas Chromatography/Mass Spectrometer (GC/MS) was used to determine the volatile/heat-labile components in Ligusticum chuanxiong Hort - Cyperus rotundus rhizomes. Facing co-eluting peaks in k samples, a trilinear structure was reconstructed to obtain the second-order advantage. The retention time (RT) shift with multi-channel detection signals for different samples has been vital in maintaining the trilinear structure, thus a modified multiscale peak alignment (mMSPA) method was proposed in this paper. The peak position and peak width of representative ion profile were firstly detected by mMSPA using Continuous Wavelet Transform with Haar wavelet as the mother wavelet (Haar CWT). Then, the raw shift was confirmed by Fast Fourier Transform (FFT) cross correlation calculation. To obtain the optimal shift, Haar CWT was again used to detect the subtle deviations and be amalgamated in calculation. Here, to ensure there is no peaks shape alternation, the alignment was performed in local domains of data matrices, and all data points in the peak zone were moved via linear interpolation in non-peak parts. Finally, chemical components of interest in Ligusticum chuanxiong Hort - Cyperus rotundus rhizomes were analyzed by HS-SPME-GCMS and mMSPA-alternating trilinear decomposition (ATLD) resolution. As a result, the concentration variation between herbs and their pharmaceutical products can provide a scientific basic for the quality standard establishment of traditional Chinese medicines. Copyright © 2018 Elsevier B.V. All rights reserved.

Wind alters landing dynamics in bumblebees.

PubMed

Chang, Jeremy J; Crall, James D; Combes, Stacey A

2016-09-15

Landing is an important but understudied behavior that flying animals must perform constantly. In still air, insects decelerate smoothly prior to landing by employing the relatively simple strategy of maintaining a constant rate of image expansion during their approach. However, it is unclear whether insects employ this strategy when faced with challenging flight environments. Here, we tested the effects of wind on bumblebees (Bombus impatiens) landing on flowers. We find that bees' approach paths to flowers shift from multidirectional in still air to unidirectional in wind, regardless of flower orientation. In addition, bees landing in a 3.5 m s -1 headwind do not decelerate smoothly, but rather maintain a high flight speed until contact, resulting in higher peak decelerations upon impact. These findings suggest that wind has a strong influence on insect landing behavior and performance, with important implications for the design of micro aerial vehicles and the ecomechanics of insect flight. © 2016. Published by The Company of Biologists Ltd.

Effects of hand grip exercise on shoulder joint internal rotation and external rotation peak torque.

PubMed

Lee, Dong-Rour; Jong-Soon Kim, Laurentius

2016-08-10

The goal of this study is to analyze the effects of hand grip training on shoulder joint internal rotation (IR)/external rotation (ER) peak torque for healthy people. The research was conducted on 23 healthy adults in their 20 s-30 s who volunteered to participate in the experiment. Hand grip power test was performed on both hands of the research subjects before/after the test to study changes in hand grip power. Isokinetic machine was used to measure the concentric IRPT (internal rotation peak torque) and concentric ERPT (external rotation peak torque) at the velocity of 60°/sec, 90°/sec, and 180°/sec before/after the test. Hand grip training was performed daily on the subject's right hand only for four weeks according to exercise program. Finally, hand grip power of both hands and the maximum torque values of shoulder joint IR/ER were measured before/after the test and analyzed. There was a statistically significant difference in the hand grip power of the right hand, which was subject to hand grip training, after the experiment. Also, statistically significant difference for shoulder ERPT was found at 60°/sec. Hand grip training has a positive effect on shoulder joint IRPT/ERPT and therefore can help strengthen muscles around the shoulder without using weight on the shoulder. Consequently, hand grip training would help maintain strengthen the muscles around the shoulder in the early phase of rehabilitation process after shoulder surgery.

77 FR 62238 - Alan B. Miller and Universal Health Services; Analysis of Agreement Containing Consent Orders To...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-12

... agreed to hold the to-be- divested assets separate, and to maintain the economic viability, marketability... maintain the economic viability, marketability, and competitiveness of the both the Peak and Mesilla Valley...

Seasonal and daily plasma corticosterone rhythms in American toads, Bufo americanus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pancak, M.K.; Taylor, D.H.

1983-06-01

Concentrations of corticosterone were measured in the plasma of American toads, Bufo americanus, on a seasonal basis using a radioimmunoassay technique. Two populations of toads, maintained under different light conditions, were monitored to observe the effects of photoperiod on the seasonal rhythm of plasma corticosterone. Under a natural photoperiod toads demonstrated a rhythm consisting of a spring peak and a fall peak in corticosterone concentration. Toads maintained under a 12L:12D photoperiod all year round demonstrated a similar rhythm with peaks in the spring and fall. This suggests that an endogenous (circannual) rhythm of corticosterone may be playing an important rolemore » in the seasonal change of overt behavior and physiology of Bufo americanus. A daily rhythm of corticosterone was also detected in toads when blood samples were taken every 4 hr. When compared to a previously published circadian rhythm study of locomotor activity, the surge in corticosterone concentration for the day occurred at 1730 just prior to the peak in locomotor activity.« less

4 Living roofs in 3 locations: Does configuration affect runoff mitigation?

NASA Astrophysics Data System (ADS)

Fassman-Beck, Elizabeth; Voyde, Emily; Simcock, Robyn; Hong, Yit Sing

2013-05-01

Four extensive living roofs and three conventional (control) roofs in Auckland, New Zealand have been evaluated over periods of 8 months to over 2 yrs for stormwater runoff mitigation. Up to 56% cumulative retention was measured from living roofs with 50-150 mm depth substrates installed over synthetic drainage layers, and with >80% plant coverage. Variation in cumulative %-retention amongst sites is attributed to different durations of monitoring, rather than actual performance. At all sites, runoff rarely occurred at all from storms with less than 25 mm of precipitation, from the combined effects of substrates designed to maximize moisture storage and because >90% of individual events were less than 25 mm. Living roof runoff depth per event is predicted well by a 2nd order polynomial model (R2 = 0.81), again demonstrating that small storms are well managed. Peak flow per event from the living roofs was 62-90% less than a corresponding conventional roof's runoff. Seasonal retention performance decreased slightly in winter, but was nonetheless substantial, maintaining 66% retention at one site compared to 45-93% in spring-autumn at two sites. Peak flow mitigation did not vary seasonally. During a 4-month period of concurrent monitoring at all sites, varied substrate depth did not influence runoff depth (volume), %-retention, or %-peak flow mitigation compared to a control roof at the same site. The magnitude of peak flow was greater from garden shed-scale living roofs compared to the full-scale living roofs. Two design aspects that could be manipulated to increase peak flow mitigation include lengthening the flow path through the drainage layer to vertical gutters and use of flow-retarding drainage layer materials.

Heart failure and anemia: Effects on prognostic variables.

PubMed

Cattadori, Gaia; Agostoni, Piergiuseppe; Corrà, Ugo; Sinagra, Gianfranco; Veglia, Fabrizio; Salvioni, Elisabetta; Bonomi, Alice; La Gioia, Rocco; Scardovi, Angela B; Ferraironi, Alessandro; Emdin, Michele; Metra, Marco; Di Lenarda, Andrea; Limongelli, Giuseppe; Raimondo, Rosa; Re, Federica; Guazzi, Marco; Belardinelli, Romualdo; Parati, Gianfranco; Caravita, Sergio; Magrì, Damiano; Lombardi, Carlo; Frigerio, Maria; Oliva, Fabrizio; Girola, Davide; Mezzani, Alessandro; Farina, Stefania; Mapelli, Massimo; Scrutinio, Domenico; Pacileo, Giuseppe; Apostolo, Anna; Iorio, AnnaMaria; Paolillo, Stefania; Filardi, Pasquale Perrone; Gargiulo, Paola; Bussotti, Maurizio; Marchese, Giovanni; Correale, Michele; Badagliacca, Roberto; Sciomer, Susanna; Palermo, Pietro; Contini, Mauro; Giannuzzi, Pantaleo; Battaia, Elisa; Cicoira, Mariantonietta; Clemenza, Francesco; Minà, Chiara; Binno, Simone; Passino, Claudio; Piepoli, Massimo F

2017-01-01

Anemia is frequent in heart failure (HF), and it is associated with higher mortality. The predictive power of established HF prognostic parameters in anemic HF patients is unknown. Clinical, laboratory, echocardiographic and cardiopulmonary-exercise-test (CPET) data were analyzed in 3913 HF patients grouped according to hemoglobin (Hb) values. 248 (6%), 857 (22%), 2160 (55%) and 648 (17%) patients had very low (<11g/dL), low (11-12 for females, 11-13 for males), normal (12-15 for females, 13-15 for males) and high (>15) Hb, respectively. Median follow-up was 1363days (606-1883). CPETs were always performed safely. Hb was related to prognosis (Hazard ratio (HR)=0.864). No prognostic difference was observed between normal and high Hb groups. Peak oxygen consumption (VO 2 ), ventilatory efficiency (VE/VCO 2 slope), plasma sodium concentration, ejection fraction (LVEF), kidney function and Hb were independently related to prognosis in the entire population. Considering Hb groups separately, peakVO 2 (very low Hb HR=0.549, low Hb HR=0.613, normal Hb HR=0.618, high Hb HR=0.542) and LVEF (very low Hb HR=0.49, low Hb HR=0.692, normal Hb HR=0.697, high Hb HR=0.694) maintained their prognostic roles. High VE/VCO 2 slope was associated with poor prognosis only in patients with low and normal Hb. Anemic HF patients have a worse prognosis, but CPET can be safely performed. PeakVO 2 and LVEF, but not VE/VCO 2 slope, maintain their prognostic power also in HF patients with Hb<11g/dL, suggesting CPET use and a multiparametric approach in HF patients with low Hb. However, the prognostic effect of an anemia-oriented follow-up is unknown. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

The slightly-enriched spectral shift control reactor. Final report, September 30, 1988--September 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, W.R.; Lee, J.C.; Larsen, E.W.

1991-11-01

An advanced converter reactor design utilizing mechanical spectral shift control rods in a conventional pressurized water reactor configuration is under investigation. The design is based on the principle that a harder spectrum during the early part of the fuel cycle will result in large neutron captures in fertile {sup 238}U, which can then be burned in situ in a softer spectrum later in the cycle. Preliminary design calculations performed during FY 89 showed that the slightly-enriched spectral shift reactor design offers the benefit of substantially increased fuel resource utilization with the proven safety characteristics of the pressurized water reactor technologymore » retained. Optimization of the fuel design and development of fuel management strategies were carried out in FY 90, along with effort to develop and validate neutronic methodology for tight-lattice configurations with hard spectra. During FY 91, the final year of the grant, the final Slightly-Enriched Spectral Shift Reactor (SESSR) design was determined, and reference design analyses were performed for the assemblies as well as the global core configuration, both at the beginning of cycle (BOC) and with depletion. The final SESSR design results in approximately a 20% increase in the utilization of uranium resources, based on equilibrium fuel cycle analyses. Acceptable pin power peaking is obtained with the final core design, with assembly peaking factors equal to less than 1.04 for spectral shift control rods both inserted and withdrawn, and global peaking factors at BOC predicted to be 1.4. In addition, a negative Moderation Temperature Coefficient (MTC) is maintained for BOC, which is difficult to achieve with conventional advanced converter designs based on a closed fuel cycle. The SESSR design avoids the need for burnable poison absorber, although they could be added if desired to increase the cycle length while maintaining a negative MTC.« less

The slightly-enriched spectral shift control reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, W.R.; Lee, J.C.; Larsen, E.W.

1991-11-01

An advanced converter reactor design utilizing mechanical spectral shift control rods in a conventional pressurized water reactor configuration is under investigation. The design is based on the principle that a harder spectrum during the early part of the fuel cycle will result in large neutron captures in fertile {sup 238}U, which can then be burned in situ in a softer spectrum later in the cycle. Preliminary design calculations performed during FY 89 showed that the slightly-enriched spectral shift reactor design offers the benefit of substantially increased fuel resource utilization with the proven safety characteristics of the pressurized water reactor technologymore » retained. Optimization of the fuel design and development of fuel management strategies were carried out in FY 90, along with effort to develop and validate neutronic methodology for tight-lattice configurations with hard spectra. During FY 91, the final year of the grant, the final Slightly-Enriched Spectral Shift Reactor (SESSR) design was determined, and reference design analyses were performed for the assemblies as well as the global core configuration, both at the beginning of cycle (BOC) and with depletion. The final SESSR design results in approximately a 20% increase in the utilization of uranium resources, based on equilibrium fuel cycle analyses. Acceptable pin power peaking is obtained with the final core design, with assembly peaking factors equal to less than 1.04 for spectral shift control rods both inserted and withdrawn, and global peaking factors at BOC predicted to be 1.4. In addition, a negative Moderation Temperature Coefficient (MTC) is maintained for BOC, which is difficult to achieve with conventional advanced converter designs based on a closed fuel cycle. The SESSR design avoids the need for burnable poison absorber, although they could be added if desired to increase the cycle length while maintaining a negative MTC.« less

Effects of shoe cleat position on physiology and performance of competitive cyclists.

PubMed

Paton, Carl D

2009-12-01

Aerobic economy is an important factor that affects the performance of competitive cyclists. It has been suggested that placing the foot more anteriorly on the bicycle pedals may improve economy over the traditional foot position by improving pedaling efficiency. The current study examines the effects of changing the anterior-posterior pedal foot position on the physiology and performance of well-trained cyclists. In a crossover study, 10 competitive cyclists completed two maximal incremental and two submaximal tests in either their preferred (control) or a forward (arch) foot position. Maximum oxygen consumption and peak power output were determined from the incremental tests for both foot positions. On two further occasions, cyclists also completed a two-part 60-min submaximal test that required them to maintain a constant power output (equivalent to 60% of their incremental peak power) for 30 min, during which respiratory and blood lactate samples were taken at predetermined intervals. Thereafter, subjects completed a 30-min self-paced maximal effort time trial. Relative to the control, the mean changes (+/-90% confidence limits) in the arch condition were as follows: maximum oxygen consumption, -0.5% (+/-2.0%); incremental peak power output, -0.8% (+/-1.3%); steady-state oxygen consumption at 60%, -2.4% (+/-1.1%); steady-state heart rate 60%, 0.4% (+/-1.7%); lactate concentration 60%, 8.7% (+/-14.4%); and mean time trial power, -1.5% (+/-2.9%). We conclude that there was no substantial physiological or performance advantage in this group using an arch-cleat shoe position in comparison with a cyclist's normal preferred condition.

Fingerprint chromatogram analysis of extracts from the leaves of Tripterygium wilfordii Hook. F. by high performance liquid chromatography.

PubMed

Li, Ke; Wang, Shudong

2005-05-01

A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the study of fingerprint chromatograms of extracts from the leaves of Tripterygium wilfordii Hook. F. (TWHF) and for controlling the quality of the herb. HPLC separation of the extracts was performed on a Lichrospher RP-18 column and detected by ultraviolet absorbance at 210 nm. The column temperature was maintained at 35 degrees C. A mobile phase composed of acetonitrile:H2O in the ratio of 39:61 (v/v) was found to be most suitable for this separation at a flow rate of 0.8 mL/min with isocratic elution. Under the chromatographic conditions described, the peak profile of the 10 components collected within 35 min made up the fingerprint of the extracts from leaves of TWHF with universal features. The fingerprint chromatograms had a good stability, precision, and reproducibility. The similarity of the extracts from leaves of TWHF collected in summer and winter was studied with triptolide as a reference peak. The method is suitable for differentiation of extracts from the leaves of TWHF, and can be used as a quality control method for this herb.

Suprapubic track pressure and force--deformation measurements in a (live) human subject and in animal models post-mortem.

PubMed

Coveney, V A; Gepi-Attee, S; Gröver, D; Painter, D

2001-01-01

Tests have been performed on animal models shortly post-mortem and on a healthy human subject in order to obtain estimates of the forces which act on suprapubic urinary catheters and similar devices and to develop an abdominal wall simulator. Such data and test methods are required for the systematic design of suprapubic devices because of the dual need to maintain the functionality of devices and to avoid excessive pressure on soft body tissue which could lead to ischaemia and in turn necrosis. In the post-mortem animal models, electrical excitation was applied to the abdominal wall in order to stimulate muscle activity. Two types of transducers were used: a soft membrane transducer (SMT) for pressure measurement and novel instrumented 'tongs' to determine indentation stiffness characteristics in the suprapubic track or artificial pathway created for a device. The SMT has been extensively used in the urethras and bladders of human subjects while the tongs were built specifically for these tests. Only the well-established SMT was used with the human subject; a peak pressure of 22 kPa was obtained. In the animal models the pressure profile given by the SMT had a peak whose position corresponded well with the estimated location of the rectus muscle measured on the fixed tissue section. The peak value was 5.5 kPa, comparable with values likely to cause necrosis if maintained for more than 1 day. Remarkably consistent indentation stiffness values were obtained with the instrumented tongs; all values were close to 0.45 N/mm (33 kPa/mm).

Low levels of specularity support operational color constancy, particularly when surface and illumination geometry can be inferred

PubMed Central

Lee, Robert J.; Smithson, Hannah E.

2016-01-01

We tested whether surface specularity alone supports operational color constancy – the ability to discriminate changes in illumination or reflectance. Observers viewed short animations of illuminant or reflectance changes in rendered scenes containing a single spherical surface, and were asked to classify the change. Performance improved with increasing specularity, as predicted from regularities in chromatic statistics. Peak performance was impaired by spatial rearrangements of image pixels that disrupted the perception of illuminated surfaces, but was maintained with increased surface complexity. The characteristic chromatic transformations that are available with non-zero specularity are useful for operational color constancy, particularly if accompanied by appropriate perceptual organisation. PMID:26974938

Variability of Jump Kinetics Related to Training Load in Elite Female Basketball.

PubMed

Legg, Jan; Pyne, David B; Semple, Stuart; Ball, Nick

2017-11-04

The purpose of this study was to quantify changes in jump performance and variability in elite female basketballers. Junior and senior female representative basketball players ( n = 10) aged 18 ± 2 years participated in this study. Countermovement jump (CMJ) data was collected with a Gymaware™ optical encoder at pre-, mid-, and post-season time points across 10 weeks. Jump performance was maintained across the course of the full season (from pre to post). Concentric peak velocity, jump height, and dip showed the most stability from pre- to post-season, with the %CV ranging from 5.6⁻8.9%. In the period of the highest training load (mid-season), the variability of within-subject performance was reduced by approximately 2⁻4% in all measures except for jump height. Altered jump mechanics through a small (0.26 effect size) increase in dip were evident at mid-season, suggesting that CMJ analysis is useful for coaches to use as an in-season monitoring tool. The highest coefficient of variation (8⁻22%CV) in inter-set scores in all measures except eccentric peak velocity also occurred mid-season. It appears that in-season load not only impairs jump performance, but also movement variability in basketball players.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konis, Kyle; Orosz, Michael; Sintov, Nicole

Competition-based “energy saving” interventions are increasingly promoted as an effective strategy for reducing energy consumption in buildings with large occupant controlled electrical loads. However, the factors that drive energy savings in such interventions are not well understood, nor are the impacts of short-term competitions on long-term energy performance. A total of 39 8-occupant suites in a freshman residence hall were instrumented with “smart” electric meters, which recorded circuit-level electricity consumption at 15-minute intervals. During a three-week Fall 2014 competition, suites competed to reduce their overall electricity demand and achieved a 6.4% reduction in whole-building demand overall and a 12% reductionmore » during hours of peak demand (from 12:00 to 19:00), despite peak seasonal temperatures and all-time record electricity demand. Analysis incorporating weather-normalized HVAC demand after the competition showed a significant “rebound” for a large portion of the suites (19), however 12 suites made further reductions, and the remainder maintained demand at the competition level. As a result, we compared energy data with self-reported survey data and identified self-efficacy beliefs, pro-environmental behaviors, and sense of affiliation with other residents of the hall as key factors distinguishing the suites with the greatest and most persistent reductions in demand from suites that maintained or increased demand.« less

Maintenance of Velocity and Power With Cluster Sets During High-Volume Back Squats.

PubMed

Tufano, James J; Conlon, Jenny A; Nimphius, Sophia; Brown, Lee E; Seitz, Laurent B; Williamson, Bryce D; Haff, G Gregory

2016-10-01

To compare the effects of a traditional set structure and 2 cluster set structures on force, velocity, and power during back squats in strength-trained men. Twelve men (25.8 ± 5.1 y, 1.74 ± 0.07 m, 79.3 ± 8.2 kg) performed 3 sets of 12 repetitions at 60% of 1-repetition maximum using 3 different set structures: traditional sets (TS), cluster sets of 4 (CS4), and cluster sets of 2 (CS2). When averaged across all repetitions, peak velocity (PV), mean velocity (MV), peak power (PP), and mean power (MP) were greater in CS2 and CS4 than in TS (P < .01), with CS2 also resulting in greater values than CS4 (P < .02). When examining individual sets within each set structure, PV, MV, PP, and MP decreased during the course of TS (effect sizes 0.28-0.99), whereas no decreases were noted during CS2 (effect sizes 0.00-0.13) or CS4 (effect sizes 0.00-0.29). These results demonstrate that CS structures maintain velocity and power, whereas TS structures do not. Furthermore, increasing the frequency of intraset rest intervals in CS structures maximizes this effect and should be used if maximal velocity is to be maintained during training.

Characterising the slope of the distance-time relationship in swimming.

PubMed

Dekerle, J; Brickley, G; Alberty, M; Pelayo, P

2010-05-01

The aim of the present study was to assess whether the critical speed calculated by the slope of the distance-time relationship (S(d-t)) represents the boundary between the heavy and severe intensity domains in swimming and would be sustainable during intermittent exercise. Nine competitive male swimmers (mean+/-SD: aged 21.2+/-2.6 yrs; peak (.)VO2 of 3866+/-529 mL min(-1)) performed, (a) four fixed-distance (100-200-400-800 m) all-out efforts to determine S(d-t) and peak (.)VO2; (b) three constant-speed efforts to exhaustion (TTE) at and 5% above and below S(d-t) (S(d-t)(+5%) and S(d-t)(-5%), respectively); (c) a set of 10 x 400 m at S(d-t) with 40-s recovery in between. Capillary blood lactate concentration ([La](B)), oxygen uptake ((.)VO2), and RPE remained stable at S(d-t)(-5%) (TTE=48.9+/-14.1 min) with end values of 3.8+/-1.9 mmol L(-1), 87+/-14% peak (.)VO2, and 4.7+/-1.3. TTE decreased at S(d-t)(+5%) (8.6+/-3.1 min), with end [La](B) of 10.2+/-1.9 mmol L(-1). Peak (.)VO2 was reached at exhaustion. Similarly, S(d-t) could only be maintained for 24.3+/-7.7 min with an increase in RPE and [La](B), (.)VO2 reaching its peak (95+/-5% peak VO2). RPE increased but [La](B) remained stable throughout the ten 400 m blocks performed at S(d-t) (overall time of 53.9+/-2.7 min). The physiological responses when swimming 5% below and 5% above S(d-t) are those characterising the heavy and severe intensity domain, respectively. While S(d-t) lies within the severe intensity domain, intermittent swims at this intensity induce [La](B) steady state alongside high rates of perceived exertion. 2009 Sports Medicine Australia. All rights reserved.

Testosterone, territorial response, and song in seasonally breeding tropical and temperate stonechats.

PubMed

Apfelbeck, Beate; Mortega, Kim G; Flinks, Heiner; Illera, Juan Carlos; Helm, Barbara

2017-04-17

Testosterone facilitates physiological, morphological, and behavioral changes required for breeding in male vertebrates. However, testosterone concentrations and the link between its seasonal changes and those in reproductive behaviors vary greatly among species. To better understand the impact of tropical and temperate environments and life history factors on this variation, we have compared testosterone, territorial behavior and song performance across sequential stages of the breeding season in males of 16 closely related taxa of East African tropical and West European temperate stonechats (Saxicola spp), which all breed during a short breeding season, but differ in migratory behavior, seasonal territory-acquisition and pace of life. We found that generally, the profiles of testosterone and territorial behavior were similar across latitudes. African stonechats with a slow pace of life had equally high peak testosterone concentrations and responded as aggressively to an intruder as European stonechats with a fast pace of life. However, song performance at the beginning of the breeding season was lower in African than in European stonechats. The differences in song performance were not associated with variation in testosterone levels between tropical and temperate stonechats. The results suggest a very similar role for testosterone as a mediator of high intensity territorial aggression during the fertile period of females in tropical and temperate stonechats, which all are highly seasonal, locally synchronous breeders. A potential explanation may be high risk of extra-pair copulations which has been associated with synchronous breeding. Interestingly, an association was not consistent for song performance. Our data suggest that song performance can be disassociated from peak testosterone levels depending on its role in breeding behavior. Despite similar testosterone levels, European males, which early in the breeding season acquire territories and mates, showed greater song performance than African stonechats, which maintain year-round territories and pair-bonds. Taken together, our study comparing related taxa of old world songbirds suggests that short breeding seasons may be a major selective force for high peak testosterone levels during breeding regardless of latitude and pace of life, but that particular behaviors, in our case song, can be uncoupled from peak testosterone levels.

Circadian intraocular pressure rhythms in athletic horses under different lighting regime.

PubMed

Bertolucci, Cristiano; Giudice, Elisabetta; Fazio, Francesco; Piccione, Giuseppe

2009-02-01

The present study was undertaken to investigate the existence of intraocular pressure (IOP) rhythms in athletic thoroughbred horses maintained under a 24 h cycle of light and darkness (LD) or under constant light (LL) or constant dark (DD) conditions. We identified an IOP circadian rhythm that is entrained to the 24 h LD cycle. IOP was low during the dark phase and high during the light phase, with a peak at the end of the light phase (ZT10). The circadian rhythm of IOP persisted in DD (with a peak at CT9.5), demonstrating an endogenous component in IOP rhythm. As previously shown in other mammalian species, horse IOP circadian rhythmicity was abolished in LL. Because tonometry is performed in horses for the diagnosis of ophthalmologic diseases, such as glaucoma or anterior uveitis, the daily variation in IOP must be taken into account in clinical practice to properly time tests and to interpret clinical findings.

Stability-maneuverability trade-offs during lateral steps.

PubMed

Acasio, Julian; Wu, Mengnan/Mary; Fey, Nicholas P; Gordon, Keith E

2017-02-01

Selecting a specific foot placement strategy to perform walking maneuvers requires the management of several competing factors, including: maintaining stability, positioning oneself to actively generate impulses, and minimizing mechanical energy requirements. These requirements are unlikely to be independent. Our purpose was to determine the impact of lateral foot placement on stability, maneuverability, and energetics during walking maneuvers. Ten able-bodied adults performed laterally-directed walking maneuvers. Mediolateral placement of the "Push-off" foot during the maneuvers was varied, ranging from a cross-over step to a side-step. We hypothesized that as mediolateral foot placement became wider, passive stability in the direction of the maneuver, the lateral impulse generated to create the maneuver, and mechanical energy cost would all increase. We also hypothesized that subjects would prefer an intermediate step width reflective of trade-offs between stability vs. both maneuverability and energy. In support of our first hypothesis, we found that as Push-off step width increased, lateral margin of stability, peak lateral impulse, and total joint work all increased. In support of our second hypothesis, we found that when subjects had no restrictions on their mediolateral foot placement, they chose a foot placement between the two extreme positions. We found a significant relationship (p<0.05) between lateral margin of stability and peak lateral impulse (r=0.773), indicating a trade-off between passive stability and the force input required to maneuver. These findings suggest that during anticipated maneuvers people select foot placement strategies that balance competing costs to maintain stability, actively generate impulses, and minimize mechanical energy costs. Published by Elsevier B.V.

Evaluation of a silicon photomultiplier PET insert for simultaneous PET and MR imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ko, Guen Bae; Kim, Kyeong Yun; Yoon, Hyun Suk

2016-01-15

Purpose: In this study, the authors present a silicon photomultiplier (SiPM)-based positron emission tomography (PET) insert dedicated to small animal imaging with high system performance and robustness to temperature change. Methods: The insert consists of 64 LYSO-SiPM detector blocks arranged in 4 rings of 16 detector blocks to yield a ring diameter of 64 mm and axial field of view of 55 mm. Each detector block consists of a 9 × 9 array of LYSO crystals (1.2 × 1.2 × 10 mm{sup 3}) and a monolithic 4 × 4 SiPM array. The temperature of each monolithic SiPM is monitored, andmore » the proper bias voltage is applied according to the temperature reading in real time to maintain uniform performance. The performance of this PET insert was characterized using National Electrical Manufacturers Association NU 4-2008 standards, and its feasibility was evaluated through in vivo mouse imaging studies. Results: The PET insert had a peak sensitivity of 3.4% and volumetric spatial resolutions of 1.92 (filtered back projection) and 0.53 (ordered subset expectation maximization) mm{sup 3} at center. The peak noise equivalent count rate and scatter fraction were 42.4 kcps at 15.08 MBq and 16.5%, respectively. By applying the real-time bias voltage adjustment, an energy resolution of 14.2% ± 0.3% was maintained and the count rate varied ≤1.2%, despite severe temperature changes (10–30 °C). The mouse imaging studies demonstrate that this PET insert can produce high-quality images useful for imaging studies on the small animals. Conclusions: The developed MR-compatible PET insert is designed for insertion into a narrow-bore magnetic resonance imaging scanner, and it provides excellent imaging performance for PET/MR preclinical studies.« less

47 CFR 80.213 - Modulation requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... must be maintained between 75 and 100 percent; (2) When phase or frequency modulation is used in the 156-162 MHz band the peak modulation must be maintained between 75 and 100 percent. A frequency... installed between the modulation limiter and the modulated radio frequency stage. At frequencies between 3 k...

76 FR 35215 - Notice of EPA Workshop on Sanitary Sewer Overflows and Peak Wet Weather Discharges

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-16

... draft Peak Flows Policy. The workshop will include a facilitated discussion with representatives of organizations that represent POTWs, state NPDES permitting authorities, and non-for-profit environmental groups... maintained sanitary sewer systems are meant to collect and transport all of the sewage that flows into them...

Marrying Step Feed with Secondary Clarifier Improvements to Significantly Increase Peak Wet Weather Treatment Capacity: An Integrated Methodology.

PubMed

Daigger, Glen T; Siczka, John S; Smith, Thomas F; Frank, David A; McCorquodale, J A

2017-08-01

  The need to increase the peak wet weather secondary treatment capacity of the City of Akron, Ohio, Water Reclamation Facility (WRF) provided the opportunity to test an integrated methodology for maximizing the peak wet weather secondary treatment capacity of activated sludge systems. An initial investigation, consisting of process modeling of the secondary treatment system and computational fluid dynamics (CFD) analysis of the existing relatively shallow secondary clarifiers (3.3 and 3.7 m sidewater depth in 30.5 m diameter units), indicated that a significant increase in capacity from 416 000 to 684 000 m3/d or more was possible by adding step feed capabilities to the existing bioreactors and upgrading the existing secondary clarifiers. One of the six treatment units at the WRF was modified, and an extensive 2-year testing program was conducted to determine the total peak wet weather secondary treatment capacity achievable. The results demonstrated that a peak wet weather secondary treatment capacity approaching 974 000 m3/d is possible as long as secondary clarifier solids and hydraulic loadings could be separately controlled using the step feed capability provided. Excellent sludge settling characteristics are routinely experienced at the City of Akron WRF, raising concerns that the identified peak wet weather secondary treatment capacity could not be maintained should sludge settling characteristics deteriorate for some reason. Computational fluid dynamics analysis indicated that the impact of the deterioration of sludge settling characteristics could be mitigated and the identified peak wet weather secondary treatment capacity maintained by further use of the step feed capability provided to further reduce secondary clarifier solids loading rates at the identified high surface overflow rates. The results also demonstrated that effluent limits not only for total suspended solids (TSS) and five-day carbonaceous biochemical oxygen demand (cBOD5) could be maintained, but also for ammonia-nitrogen and total phosphorous (TP). Although hydraulic limitations in other parts of the WRP prevent this full capacity to be realized, the City is proceeding to implement the modifications identified using this integrated methodology.

Empiric 6-food elimination diet induced and maintained prolonged remission in patients with adult eosinophilic esophagitis: a prospective study on the food cause of the disease.

PubMed

Lucendo, Alfredo J; Arias, Ángel; González-Cervera, Jesús; Yagüe-Compadre, José Luis; Guagnozzi, Danila; Angueira, Teresa; Jiménez-Contreras, Susana; González-Castillo, Sonia; Rodríguez-Domíngez, Benito; De Rezende, Livia C; Tenias, José M

2013-03-01

Although empiric exclusion from the diet of the 6 food groups most likely to trigger allergies achieves eosinophilic esophagitis (EoE) remission in children, data on its prolonged efficacy and effects on adults are lacking. We sought to evaluate the efficacy of a 6-food elimination diet in inducing and maintaining prolonged remission in patients with adult EoE. Sixty-seven consecutive patients with adult EoE were prospectively recruited and treated exclusively with a diet avoiding cereals, milk, eggs, fish/seafood, legumes/peanuts, and soy for 6 weeks. Subsequent challenge was undertaken by sequentially reintroducing all excluded single foods, followed by endoscopy and biopsies, which were developed every 6 weeks in case of response (eosinophil peak count reduction to <15/high-power field [hpf]). A food was considered a trigger for EoE and removed from the diet if pathologic eosinophilic infiltration (≥15 eosinophils/hpf) reappeared. Food-specific serum IgE measurements and skin prick tests were performed before initiating the diet. Forty-nine (73.1%) patients exhibited significantly reduced eosinophil peak counts (<15 eosinophils/hpf) before sequential single-food reintroduction. A single offending food antigen was identified in 35.71% of patients, 2 food triggers were identified in 30.95%, and 3 or more food triggers were identified in 33.3%. Cow's milk was the most common food antigen (61.9%), followed by wheat (28.6%), eggs (26.2%), and legumes (23.8%). Prior allergy tests showed no concordance with food-reintroduction challenge results. All patients who continued to avoid the offending foods maintained histopathologic and clinical EoE remission for up to 3 years. An empiric 6-food elimination diet effectively induced remission of active adult EoE, which was maintained for up to 3 years with individually tailored, limited exclusion diets. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Comparing the effects of two in-flight aerobic exercise protocols on standing heart rates and VO(2peak) before and after space flight

NASA Technical Reports Server (NTRS)

Siconolfi, S. F.; Charles, J. B.; Moore, A. D. Jr; Barrows, L. H.

1994-01-01

The effects of regular aerobic exercise on orthostatic tolerance have been the subject of a long-standing controversy that will influence the use of exercise during space flight. To examine these effects, astronauts performed continuous (CE) aerobic exercise (n = 8), interval (IE) aerobic exercise (n = 4), or no (NE) exercise (n = 5) during flights of 7 to 11 days. Heart rate (HR) responses to an orthostatic challenge (stand test) were measured 10 days before flight and on landing day. VO(2peak) (graded treadmill exercise) was measured 7 to 21 days before and 2 days after flight. No significant differences across the groups were observed in standing HRs before or after flight. However, the within-group mean HRs significantly increased in the NE (71-89 beats/min) and CE (60-85 beats/min) groups after space flight. The HRs for the IE group did not significantly increase (75-86 beats/min) after space flight. VO(2peak) decreased (P < .05) in the NE (-9.5%) group, but did not change in the CE (-2.4%) and IE (1%) groups. The relationship (r = 0.237) between the delta HR and delta VO(2peak) was not significant. These preliminary results indicate that: (1) continuous exercise does not affect the orthostatic HR response after space flight; (2) interval exercise may minimize an increase in the postflight orthostatic HR; and (3) both exercise protocols can maintain VO(2peak).

Temporal Aspects of the V[o.sub.2] Response at the Power Output Associated with V[o.sub.2]peak in Well Trained Cyclists-Implications for Interval Training Prescription

ERIC Educational Resources Information Center

Laursen, Paul B.; Shing, Cecilia M.; Jenkins, David G.

2004-01-01

The power output achieved at peak oxygen consumption (V[O.sub.2]peak) and the time this power can be maintained (i.e., Tmax) have been used in prescribing high-intensity interval training. In this context, the present study examined temporal aspects of the V[O.sub.2] response to exercise at the cycling power that output well trained cyclists…

Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers

PubMed Central

Ross, Megan L.; Garvican‐Lewis, Laura A.; Welvaert, Marijke; Heikura, Ida A.; Forbes, Sara G.; Mirtschin, Joanne G.; Cato, Louise E.; Strobel, Nicki; Sharma, Avish P.; Hawley, John A.

2017-01-01

Key points Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support.Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole‐body fat oxidation during exercise in race walkers over a range of exercise intensities.The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real‐life race performance in elite race walkers.In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity. Abstract We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world‐class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg−1 day−1: 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day−1 CHO; 78% energy as fat; 2.1 g kg−1 day−1 protein; LCHF, n = 10). Post‐intervention, V˙O2 peak during race walking increased in all groups (P < 0.001, 90% CI: 2.55, 5.20%). LCHF was associated with markedly increased rates of whole‐body fat oxidation, attaining peak rates of 1.57 ± 0.32 g min−1 during 2 h of walking at ∼80% V˙O2 peak . However, LCHF also increased the oxygen (O2) cost of race walking at velocities relevant to real‐life race performance: O2 uptake (expressed as a percentage of new V˙O2 peak ) at a speed approximating 20 km race pace was reduced in HCHO and PCHO (90% CI: −7.047, −2.55 and −5.18, −0.86, respectively), but was maintained at pre‐intervention levels in LCHF. HCHO and PCHO groups improved times for 10 km race walk: 6.6% (90% CI: 4.1, 9.1%) and 5.3% (3.4, 7.2%), with no improvement (−1.6% (−8.5, 5.3%)) for the LCHF group. In contrast to training with diets providing chronic or periodised high‐CHO availability, and despite a significant improvement in V˙O2 peak , adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy. PMID:28012184

Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers.

PubMed

Burke, Louise M; Ross, Megan L; Garvican-Lewis, Laura A; Welvaert, Marijke; Heikura, Ida A; Forbes, Sara G; Mirtschin, Joanne G; Cato, Louise E; Strobel, Nicki; Sharma, Avish P; Hawley, John A

2017-05-01

Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support. Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole-body fat oxidation during exercise in race walkers over a range of exercise intensities. The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real-life race performance in elite race walkers. In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity. We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world-class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg -1  day -1 : 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day -1 CHO; 78% energy as fat; 2.1 g kg -1  day -1 protein; LCHF, n = 10). Post-intervention, V̇O2 peak during race walking increased in all groups (P < 0.001, 90% CI: 2.55, 5.20%). LCHF was associated with markedly increased rates of whole-body fat oxidation, attaining peak rates of 1.57 ± 0.32 g min -1 during 2 h of walking at ∼80% V̇O2 peak . However, LCHF also increased the oxygen (O 2 ) cost of race walking at velocities relevant to real-life race performance: O 2 uptake (expressed as a percentage of new V̇O2 peak ) at a speed approximating 20 km race pace was reduced in HCHO and PCHO (90% CI: -7.047, -2.55 and -5.18, -0.86, respectively), but was maintained at pre-intervention levels in LCHF. HCHO and PCHO groups improved times for 10 km race walk: 6.6% (90% CI: 4.1, 9.1%) and 5.3% (3.4, 7.2%), with no improvement (-1.6% (-8.5, 5.3%)) for the LCHF group. In contrast to training with diets providing chronic or periodised high-CHO availability, and despite a significant improvement in V̇O2 peak , adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy. © 2016 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Changes in storm peak flows after clearcut logging

Treesearch

Jack Lewis

1997-01-01

Streamflow in a rain-dominated, 473-ha watershed bearing second-growth redwood forest was monitored at 13 locations before and after 50% of the watershed was logged, primarily by clearcutting. Three gauged subwatersheds were maintained as unlogged controls through-out the 11-year study period. The analysis included 526 observations of peak flow from 59 storm events....

Aeromagnetic map of the Glacier Peak Wilderness and adjacent areas, Chelan, Skagit, and Snohomish counties, Washington

USGS Publications Warehouse

Flanigan, V.J.; Sherrard, Mark

1985-01-01

The Glacier Peak Wilderness encompasses 464,741 acres, including 483 acres of patented mining and millsite claims. Also included in the present study are nine areas adjoining the wilderness (see fig. 1), totaling 90,034 acres of recommended wilderness additions. All these lands are here collectively called the “study area.” Access to the study area is provided by generally well maintained trails from gravel or dirt roads along major valleys above Darrington, Marblemount, Stehekin, Holden, Trinity, and Lake Wnatchee. Other than the main access trails across a few passes (Cloudy Pass, Buck Creek Pass, White Pass, and Indian Pass), trails are rough, infrequently maintained, or nonexistent.

SU-D-304-01: Development of An Applicator for Treating Shallow and Moving Tumors with Respiratory-Gated Spot-Scanning Proton Therapy Using Real-Time Image Guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsuura, T; Fujii, Y; Takao, S

Purpose: To develop a method for treating shallow and moving tumors (e.g., lung tumors) with respiratory-gated spot-scanning proton therapy using real-time image guidance (RTPT). Methods: An applicator was developed which can be installed by hand on the treatment nozzle. The mechanical design was considered such that the Bragg peaks are placed at the patient surface while a sufficient field of view (FOV) of fluoroscopic X-rays was maintained during the proton beam delivery. To reduce the treatment time maintaining the robustness of the dose distribution with respect to motion, a mini-ridge filter (MRF) was sandwiched between two energy absorbers. The measurementsmore » were performed to obtain a data for beam modeling and to verify the spot position-invariance of a pencil beam dose distribution. For three lung cancer patients, treatment plans were made with and without the MRF and the effects of the MRF were evaluated. Next, the effect of respiratory motion on the dose distribution was investigated. Results: To scan the proton beam over a 14 x 14 cm area while maintaining the φ16 cm of fluoroscopic FOV, the lower face of the applicator was set 22 cm upstream of the isocenter. With an additional range variance of 2.2 mm and peak-to-peak distance of 4 mm of the MRF, the pencil beam dose distribution was unchanged with the displacement of the spot position. The quality of the treatment plans was not worsened by the MRF. With the MRF, the number of energy layers was reduced to less than half and the treatment time by 26–37%. The simulation study showed that the interplay effect was successfully suppressed by respiratory-gating both with and without MRF. Conclusions: The spot-scanning proton beam was successfully delivered to shallow and moving tumors within a sufficiently short time by installing the developed applicator at the RTPT nozzle.« less

Dynamic balance during walking adaptability tasks in individuals post-stroke.

PubMed

Vistamehr, Arian; Balasubramanian, Chitralakshmi K; Clark, David J; Neptune, Richard R; Fox, Emily J

2018-06-06

Maintaining dynamic balance during community ambulation is a major challenge post-stroke. Community ambulation requires performance of steady-state level walking as well as tasks that require walking adaptability. Prior studies on balance control post-stroke have mainly focused on steady-state walking, but walking adaptability tasks have received little attention. The purpose of this study was to quantify and compare dynamic balance requirements during common walking adaptability tasks post-stroke and in healthy adults and identify differences in underlying mechanisms used for maintaining dynamic balance. Kinematic data were collected from fifteen individuals with post-stroke hemiparesis during steady-state forward and backward walking, obstacle negotiation, and step-up tasks. In addition, data from ten healthy adults provided the basis for comparison. Dynamic balance was quantified using the peak-to-peak range of whole-body angular-momentum in each anatomical plane during the paretic, nonparetic and healthy control single-leg-stance phase of the gait cycle. To understand differences in some of the key underlying mechanisms for maintaining dynamic balance, foot placement and plantarflexor muscle activation were examined. Individuals post-stroke had significant dynamic balance deficits in the frontal plane across most tasks, particularly during the paretic single-leg-stance. Frontal plane balance deficits were associated with wider paretic foot placement, elevated body center-of-mass, and lower soleus activity. Further, the obstacle negotiation task imposed a higher balance requirement, particularly during the trailing leg single-stance. Thus, improving paretic foot placement and ankle plantarflexor activity, particularly during obstacle negotiation, may be important rehabilitation targets to enhance dynamic balance during post-stroke community ambulation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Does power indicate capacity? 30-s Wingate anaerobic test vs. maximal accumulated O2 deficit.

PubMed

Minahan, C; Chia, M; Inbar, O

2007-10-01

The purpose of this study was to evaluate the relationship between anaerobic power and capacity. Seven men and seven women performed a 30-s Wingate Anaerobic Test on a cycle ergometer to determine peak power, mean power, and the fatigue index. Subjects also cycled at a work rate predicted to elicit 120 % of peak oxygen uptake to exhaustion to determine the maximal accumulated O (2) deficit. Peak power and the maximal accumulated O (2) deficit were significantly correlated (r = 0.782, p = 0.001). However, when the absolute difference in exercise values between groups (men and women) was held constant using a partial correlation, the relationship diminished (r = 0.531, p = 0.062). In contrast, we observed a significant correlation between fatigue index and the maximal accumulated O (2) deficit when controlling for gender (r = - 0.597, p = 0.024) and the relationship remained significant when values were expressed relative to active muscle mass. A higher anaerobic power does not indicate a greater anaerobic capacity. Furthermore, we suggest that the ability to maintain power output during a 30-s cycle sprint is related to anaerobic capacity.

Ammonia-based feedforward and feedback aeration control in activated sludge processes.

PubMed

Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

2014-01-01

Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

Modified sprint interval training protocols: physiological and psychological responses to 4 weeks of training.

PubMed

McKie, Greg L; Islam, Hashim; Townsend, Logan K; Robertson-Wilson, Jennifer; Eys, Mark; Hazell, Tom J

2018-06-01

Sprint interval training (SIT) protocols involving brief (≤15 s) work bouts improve aerobic and anaerobic performance, highlighting peak speed generation as a potentially important adaptive stimulus. To determine the physiological and psychological effects of reducing the SIT work bout duration, while maintaining total exercise and recovery time, 43 healthy males (n = 27) and females (n = 16) trained for 4 weeks (3 times/week) using one of the following running SIT protocols: (i) 30:240 (n = 11; 4-6 × 30-s bouts, 4 min rest); (ii) 15:120 (n = 11; 8-12 × 15-s bouts, 2 min rest); (iii) 5:40 (n = 12; 24-36 × 5-s bouts, 40 s rest); or (iv) served as a nonexercising control (n = 9). Protocols were matched for total work (2-3 min) and rest (16-24 min) durations, as well as the work-to-rest ratio (1:8 s). Pre- and post-training measures included a graded maximal oxygen consumption test, a 5-km time trial, and a 30-s maximal sprint test. Self-efficacy, enjoyment, and intentions were assessed following the last training session. Training improved maximal oxygen consumption (5.5%; P = 0.006) and time-trial performance (5.2%; P = 0.039), with a main effect of time for peak speed (1.7%; P = 0.042), time to peak speed (25%; P < 0.001), and body fat percentage (1.4%; P < 0.001) that appeared to be driven by the training. There were no group effects for self-efficacy (P = 0.926), enjoyment (P = 0.249), or intentions to perform SIT 3 (P = 0.533) or 5 (P = 0.951) times/week. This study effectively demonstrated that the repeated generation of peak speed during brief SIT work bouts sufficiently stimulates adaptive mechanisms promoting increases in aerobic and anaerobic capacity.

Pediatric endurance and limb strengthening (PEDALS) for children with cerebral palsy using stationary cycling: a randomized controlled trial.

PubMed

Fowler, Eileen G; Knutson, Loretta M; Demuth, Sharon K; Siebert, Kara L; Simms, Victoria D; Sugi, Mia H; Souza, Richard B; Karim, Roksana; Azen, Stanley P

2010-03-01

Effective interventions to improve and maintain strength (force-generating capacity) and endurance are needed for children with cerebral palsy (CP). This study was performed to examine the effects of a stationary cycling intervention on muscle strength, locomotor endurance, preferred walking speed, and gross motor function in children with spastic diplegic CP. This was a phase I randomized controlled trial with single blinding. The interventions were performed in community-based outpatient physical therapy clinics. Outcome assessments were performed in university laboratories. Sixty-two ambulatory children aged 7 to 18 years with spastic diplegic CP and Gross Motor Function Classification System levels I to III participated in this study. Participants were randomly assigned to cycling or control (no-intervention) groups. Thirty intervention sessions occurred over 12 weeks. Primary outcomes were peak knee extensor and flexor moments, the 600-Yard Walk-Run Test, the Thirty-Second Walk Test, and the Gross Motor Function Measure sections D and E (GMFM-66). Significant baseline-postintervention improvements were found for the 600-Yard Walk-Run Test, the GMFM-66, peak knee extensor moments at 120 degrees /s, and peak knee flexor moments at 30 degrees /s for the cycling group. Improved peak knee flexor moments at 120 degrees/s were found for the control group only, although not all participants could complete this speed of testing. Significant differences between the cycling and control groups based on change scores were not found for any outcomes. Limitations Heterogeneity of the patient population and intrasubject variability were limitations of the study. Significant improvements in locomotor endurance, gross motor function, and some measures of strength were found for the cycling group but not the control group, providing preliminary support for this intervention. As statistical differences were not found in baseline-postintervention change scores between the 2 groups; the results did not demonstrate that stationary cycling was more effective than no intervention. The results of this phase I study provide guidance for future research.

Influence of Electrotactile Tongue Feedback on Controlling Upright Stance during Rotational and/or Translational Sway-referencing with Galvanic Vestibular Stimulation

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Tyler, Mitchell E.; Bach-y-Rita, Paul; MacDougall, Hamish G.; Moore, Steven T.; Stallings, Valerie L.; Paloski, William H.; Black, F. Owen

2007-01-01

Integration of multi-sensory inputs to detect tilts relative to gravity is critical for sensorimotor control of upright orientation. Displaying body orientation using electrotactile feedback to the tongue has been developed by Bach-y-Rita and colleagues as a sensory aid to maintain upright stance with impaired vestibular feedback. MacDougall et al. (2006) recently demonstrated that unpredictably varying Galvanic vestibular stimulation (GVS) significantly increased anterior-posterior (AP) sway during rotational sway referencing with eyes closed. The purpose of this study was to assess the influence of electrotactile feedback on postural control performance with pseudorandom binaural bipolar GVS. Postural equilibrium was measured with a computerized hydraulic platform in 10 healthy adults (6M, 4F, 24-65 y). Tactile feedback (TF) of pitch and roll body orientation was derived from a two-axis linear accelerometer mounted on a torso belt and displayed on a 144-point electrotactile array held against the anterior dorsal tongue (BrainPort, Wicab, Inc., Middleton, WI). Subjects were trained to use TF by voluntarily swaying to draw figures on their tongue, both with and without GVS. Subjects were required to keep the intraoral display in their mouths on all trials, including those that did not provide TF. Subjects performed 24 randomized trials (20 s duration with eyes closed) including four support surface conditions (fixed, rotational sway-referenced, translating the support surface proportional to AP sway, and combined rotational-translational sway-referencing), each repeated twice with and without GVS, and with combined GVS and TF. Postural performance was assessed using deviations from upright (peak-to-peak and RMS sway) and convergence toward stability limits (time and distance to base of support boundaries). Postural stability was impaired with GVS in all platform conditions, with larger decrements in performance during trials with rotation sway-referencing. Electrotactile feedback improved performance with GVS toward non-GVS levels, again with the greatest improvement during trials with rotation sway-referencing. These results demonstrate the effectiveness of tongue electrotactile feedback in providing sensory substitution to maintain postural stability with distorted vestibular input.

Phenomenological study of the ionisation density-dependence of TLD-100 peak 5a.

PubMed

Brandan, Maria-Ester; Angeles, Oscar; Mercado-Uribe, Hilda

2006-01-01

Horowitz and collaborators have reported evidence on the structure of TLD-100 peak 5. A satellite peak, called 5a, has been singled out as arising from localised electron-hole recombination in a trap/luminescent centre, its emission mechanism would be geminate recombination and, therefore, its population would depend on incident radiation ionisation density. We report a phenomenological study of peak 4, 5a and 5 strengths for glow curves previously measured at UNAM for gammas, electrons and low-energy ions. The deconvolution procedure has followed strict rules to assure that the glow curve, where the presence of peak 5a is not visually noticeable, is decomposed in a consistent fashion, maintaining fixed widths and relative temperature difference between all the peaks. We find no improvement in the quality of the fit after inclusion of peak 5a. The relative contribution of peak 5a with respect to peak 5 does not seem to correlate with the radiation linear energy transfer.

Physiological and Selective Attention Demands during an International Rally Motor Sport Event

PubMed Central

Turner, Anthony P.; Richards, Hugh

2015-01-01

Purpose. To monitor physiological and attention responses of drivers and codrivers during a World Rally Championship (WRC) event. Methods. Observational data were collected from ten male drivers/codrivers on heart rate (HR), core body (T core) and skin temperature (T sk), hydration status (urine osmolality), fluid intake (self-report), and visual and auditory selective attention (performance tests). Measures were taken pre-, mid-, and postcompetition day and also during the precompetition reconnaissance. Results. In ambient temperatures of 20.1°C (in-car peak 33.9°C) mean (SD) peak HR and T core were significantly elevated (P < 0.05) during rally compared to reconnaissance (166 (17) versus 111 (16) beats·min−1 and 38.5 (0.4) versus 37.6 (0.2)°C, resp.). Values during competitive stages were substantially higher in drivers. High urine osmolality was indicated in some drivers within competition. Attention was maintained during the event but was significantly lower prerally, though with considerable individual variation. Conclusions. Environmental and physical demands during rally competition produced significant physiological responses. Challenges to thermoregulation, hydration status, and cognitive function need to be addressed to minimise potentially negative effects on performance and safety. PMID:25866799

Physiological and selective attention demands during an international rally motor sport event.

PubMed

Turner, Anthony P; Richards, Hugh

2015-01-01

To monitor physiological and attention responses of drivers and codrivers during a World Rally Championship (WRC) event. Observational data were collected from ten male drivers/codrivers on heart rate (HR), core body (T core) and skin temperature (T sk), hydration status (urine osmolality), fluid intake (self-report), and visual and auditory selective attention (performance tests). Measures were taken pre-, mid-, and postcompetition day and also during the precompetition reconnaissance. In ambient temperatures of 20.1°C (in-car peak 33.9°C) mean (SD) peak HR and T core were significantly elevated (P < 0.05) during rally compared to reconnaissance (166 (17) versus 111 (16) beats · min(-1) and 38.5 (0.4) versus 37.6 (0.2)°C, resp.). Values during competitive stages were substantially higher in drivers. High urine osmolality was indicated in some drivers within competition. Attention was maintained during the event but was significantly lower prerally, though with considerable individual variation. Environmental and physical demands during rally competition produced significant physiological responses. Challenges to thermoregulation, hydration status, and cognitive function need to be addressed to minimise potentially negative effects on performance and safety.

Peak power ratio generator

DOEpatents

Moyer, Robert D.

1985-01-01

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

Peak power ratio generator

DOEpatents

Moyer, R.D.

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

Peak oil and health in low- and middle-income countries: impacts and potential responses.

PubMed

Winch, Peter; Stepnitz, Rebecca

2011-09-01

Peak oil refers to the predicted peak and subsequent decline in global production of petroleum products over the coming decades. We describe how peak oil will affect health, nutrition, and health systems in low- and middle-income countries along 5 pathways. The negative effects of peak oil on health and nutrition will be felt most acutely in the 58 low-income countries experiencing minimal or negative economic growth because of their patterns of sociopolitical, geographic, and economic vulnerability. The global health community needs to take additional steps to build resilience among the residents of low- and middle-income countries and maintain access to maternal and other health services in the face of predicted changes in availability and price of fossil fuels.

Minibeam radiotherapy with small animal irradiators; in vitro and in vivo feasibility studies

NASA Astrophysics Data System (ADS)

Bazyar, Soha; Inscoe, Christina R.; O'Brian, E. Timothy; Zhou, Otto; Lee, Yueh Z.

2017-12-01

Minibeam radiation therapy (MBRT) delivers an ultrahigh dose of x-ray (⩾100 Gy) in 200-1000 µm beams (peaks), separated by wider non-irradiated regions (valleys) usually as a single temporal fraction. Preclinical studies performed at synchrotron facilities revealed that MBRT is able to ablate tumors while maintaining normal tissue integrity. The main purpose of the present study was to develop an efficient and accessible method to perform MBRT using a conventional x-ray irradiator. We then tested this new method both in vitro and in vivo. Using commercially available lead ribbon and polyethylene sheets, we constructed a collimator that converted the cone beam of an industrial irradiator to 44 identical beams (collimator size  ≈  4  ×  10 cm). The dosimetry characteristics of the generated beams were evaluated using two different radiochromic films (beam FWHM  =  246  ±  32 µm center-to-center  =  926  ±  23 µm peak-to-valley dose ratio  =  24.35  ±  2.10 collimator relative output factor  =  0.84  ±  0.04). Clonogenic assays demonstrated the ability of our method to induce radiobiological cell death in two radioresistant murine tumor cell lines (TRP  =  glioblastoma B16-F10  =  melanoma). A radiobiological equivalent dose (RBE) was calculated by evaluating the acute skin response to graded doses of MBRT and conventional radiotherapy (CRT). Normal mouse skin demonstrated resistance to doses up to 150 Gy on peak. MBRT significantly extended the survival of mice with flank melanoma tumors compared to CRT when RBE were applied (overall p  <  0.001). Loss of spatial resolution deep in the tissue has been a major concern. The beams generated using our collimator maintained their resolution in vivo (mouse brain tissue) and up to 10 cm deep in the radiochromic film. In conclusion, the initial dosimetric, in vitro and in vivo evaluations confirmed the utility of this affordable and easy-to-replicate minibeam collimator for future preclinical studies.

Contributions of Astronauts Aerobic Exercise Intensity and Time on Change in VO2peak during Spaceflight

NASA Technical Reports Server (NTRS)

Downs, Meghan E.; Buxton, Roxanne; Moore, Alan; Ploutz-Snyder, Robert; Ploutz-Snyder, Lori

2014-01-01

There is considerable variability among astronauts with respect to changes in maximal aerobic capacity (VO2peak) during International Space Station (ISS) missions, ranging from a 5% increase to 30% decline. Individual differences may be due to in-flight aerobic exercise time and intensity. PURPOSE: To evaluate the effects of in-flight aerobic exercise time and intensity on change in VO2peak during ISS missions. METHODS: Astronauts (N=11) performed peak cycle tests approx 60 days before flight (L-60), on flight day (FD) approx 14, and every approx 30 days thereafter. Metabolic gas analysis and heart rate (HR) were measured continuously during the test using the portable pulmonary function system. HR and duration of each in-flight cycle ergometer and treadmill (TM) session were recorded and averaged in time segments corresponding to each peak test. Mixed effects linear regression with exercise mode (TM or cycle) as a categorical variable was used to assess the contributions of exercise intensity (%time >70% peak HR or %time >90% peak HR) and time (min/wk), adjusted for body weight, on %change in VO2peak during the mission, and incorporating the repeated-measures experimental design. RESULTS: 110 observations were included in the model (4-6 peak cycle tests per astronaut, 2 exercise devices). VO2peak was reduced from preflight throughout the mission (FD14: 13+/-13% and FD 105: 8+/-10%). Exercise intensity (%peak HR: FD14=66+/-14; FD105=75+/-8) and time (min/wk: FD14=82+/-46; FD105=158+/-40) increased during flight. The models showed main effects for exercise time and intensity with no interactions between time, intensity, and device (70% peak HR: time [z-score=2.39; P=0.017], intensity [z-score=3.51; P=0.000]; 90% peak HR: time [zscore= 3.31; P=0.001], intensity [z-score=2.24; P=0.025]). CONCLUSION: Exercise time and intensity independently contribute to %change in VO2peak during ISS missions, indicating that there are minimal values for exercise time and intensity required to maintain VO2peak. As the FD105 average exercise intensity and time did not prevent a decline in VO2peak from preflight, astronauts' exercise prescriptions should target at least 160 min of weekly aerobic exercise at an average above 75% peak HR with increased time at intensities above 90% of peak HR starting early in the mission.

Drayage Truckers Best Practices

EPA Pesticide Factsheets

Drayage truckers best practices include: replacing older trucks with newer cleaner trucks, avoiding idling, maintaining engines, retrofitting trucks with verified technologies, and operating during off-peak hours.

Cardiorespiratory Fitness and Body Composition Responses to Different Intensities and Frequencies of Exercise Training in Colorectal Cancer Survivors.

PubMed

Devin, James L; Jenkins, David G; Sax, Andrew T; Hughes, Gareth I; Aitken, Joanne F; Chambers, Suzanne K; Dunn, Jeffrey C; Bolam, Kate A; Skinner, Tina L

2018-06-01

Deteriorations in cardiorespiratory fitness (V˙o 2peak ) and body composition are associated with poor prognosis after colorectal cancer treatment. However, the optimal intensity and frequency of aerobic exercise training to improve these outcomes in colorectal cancer survivors is unknown. This trial compared 8 weeks of moderate-intensity continuous exercise (MICE; 50 minutes; 70% peak heart rate [HR peak ]; 24 sessions), with high-intensity interval exercise (HIIE; 4 × 4 minutes; 85%-95% HR peak ) at an equivalent (HIIE; 24 sessions) and tapered frequency (HIIE-T; 16 sessions) on V˙o 2peak and on lean and fat mass, measured at baseline, 4, 8, and 12 weeks. Increases in V˙o 2peak were significantly greater after both 4 (+3.0 mL·kg -1 ·min -1 , P = .008) and 8 (+2.3 mL·kg -1 ·min -1 , P = .049) weeks of HIIE compared to MICE. After 8 weeks, there was a significantly greater reduction in fat mass after HIIE compared to MICE (-0.7 kg, P = .038). Four weeks after training, the HIIE group maintained elevated V˙o 2peak (+3.3 mL·kg -1 ·min -1 , P = .006) and reduced fat mass (-0.7 kg, P = .045) compared to the MICE group, with V˙o 2peak in the HIIE-T also being superior to the MICE group (+2.8 mL·kg -1 ·min -1 , P = .013). Compared to MICE, HIIE promotes superior improvements and short-term maintenance of V˙o 2peak and fat mass improvements. HIIE training at a reduced frequency also promotes maintainable cardiorespiratory fitness improvements. In addition to promoting accelerated and superior benefits to the current aerobic exercise guidelines, HIIE promotes clinically relevant improvements even with a substantial reduction in exercise training and for a period after withdrawal. Copyright © 2018 Elsevier Inc. All rights reserved.

Applied Meteorology Unit (AMU) Quarterly Report - Fourth Quarter FY-10

NASA Technical Reports Server (NTRS)

Bauman, William; Crawford, Winifred; Barrett, Joe; Watson, Leela; Wheeler, Mark

2010-01-01

Three AMU tasks were completed in this Quarter, each resulting in a forecast tool now being used in operations and a final report documenting how the work was done. AMU personnel completed the following tasks (1) Phase II of the Peak Wind Tool for General Forecasting task by delivering an improved wind forecasting tool to operations and providing training on its use; (2) a graphical user interface (GUI) she updated with new scripts to complete the ADAS Update and Maintainability task, and delivered the scripts to the Spaceflight Meteorology Group on Johnson Space Center, Texas and National Weather Service in Melbourne, Fla.; and (3) the Verify MesoNAM Performance task after we created and delivered a GUI that forecasters will use to determine the performance of the operational MesoNAM weather model forecast.

Rocket flight of a multilayer coated high-density EUV toroidal grating

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A. M.; Thomas, Roger J.; Davila, Joseph M.

1992-01-01

A multilayer coated high density toroidal grating was flown on a sounding rocket experiment in the Solar EUV Rocket Telescope and Spectrograph (SERTS) instrument. To our knowledge this is the first space flight of a multilayer coated grating. Pre-flight performance evaluation showed that the application of a 10-layer Ir/Si multilayer coating to the 3600 l/mm blazed toroidal replica grating produced a factor of 9 enhancement in peak efficiency near the design wavelength around 30 nm in first order over the standard gold coating, with a measured EUV efficiency that peaked at 3.3 percent. In addition, the grating's spectral resolution of better than 5000 was maintained. The region of enhanced grating efficiency due to the multilayer coating is clearly evident in the flight data. Within the bandpass of the multilayer coating, the recorded film densities were roughly equivalent to those obtained with a factor of six longer exposure on the previous flight of the SERTS instrument.

Inertial Energy Storage for Spacecraft

NASA Technical Reports Server (NTRS)

Rodriguez, G. E.

1984-01-01

The feasibility of inertial energy storage in a spacecraft power system is evaluated on the basis of a conceptual integrated design that encompasses a composite rotor, magnetic suspension and a permanent magnet (PM) motor/generator for a 3-kW orbital average payload at a bus distribution voltage of 250 volts dc. The conceptual design, is referred to as a Mechanical Capacitor. The baseline power system configuration selected is a series system employing peak-power-tracking for a Low Earth-Orbiting application. Power processing, required in the motor/generator, provides potential alternative that can only be achieved in systems with electrochemical energy storage by the addition of power processing components. One such alternative configuration provides for peak-power-tracking of the solar array and still maintains a regulated bus, without the expense of additional power processing components. Precise speed control of the two counterrotating wheels is required to reduce interaction with the attitude control system (ACS) or alternatively, used to perform attitude control functions.

Chordwise implementation of pneumatic artificial muscles to actuate a trailing edge flap

NASA Astrophysics Data System (ADS)

Vocke, R. D., III; Kothera, C. S.; Wereley, N. M.

2018-07-01

This work describes the theoretical design and experimental validation of a rotorcraft-specific trailing edge flap powered by pneumatic artificial muscle actuators. The actuators in this work are co-located outboard on the rotor blade with the flap and arranged with a chordwise orientation where diameter and length restrictions can severely limit the operating range of the system. Techniques for addressing this configuration, such as introducing a bias contraction and mechanism optimization, are discussed and a numerical optimization is performed for an actuation system sized for implementation on a medium utility helicopter rotor. The optimized design achieves ±10° of deflection at 1/rev, and maintains at least ±2° half peak-to-peak deflection out to 10/rev, indicating that the system has the actuation authority and bandwidth necessary for both primary control and vibration/noise reduction. Portions of this paper were presented at the AHS 70th Annual Forum, Montréal, Québec, Canada, May 20–22, 2014.

Monte Carlo simulation of efficient data acquisition for an entire-body PET scanner

NASA Astrophysics Data System (ADS)

Isnaini, Ismet; Obi, Takashi; Yoshida, Eiji; Yamaya, Taiga

2014-07-01

Conventional PET scanners can image the whole body using many bed positions. On the other hand, an entire-body PET scanner with an extended axial FOV, which can trace whole-body uptake images at the same time and improve sensitivity dynamically, has been desired. The entire-body PET scanner would have to process a large amount of data effectively. As a result, the entire-body PET scanner has high dead time at a multiplex detector grouping process. Also, the entire-body PET scanner has many oblique line-of-responses. In this work, we study an efficient data acquisition for the entire-body PET scanner using the Monte Carlo simulation. The simulated entire-body PET scanner based on depth-of-interaction detectors has a 2016-mm axial field-of-view (FOV) and an 80-cm ring diameter. Since the entire-body PET scanner has higher single data loss than a conventional PET scanner at grouping circuits, the NECR of the entire-body PET scanner decreases. But, single data loss is mitigated by separating the axially arranged detector into multiple parts. Our choice of 3 groups of axially-arranged detectors has shown to increase the peak NECR by 41%. An appropriate choice of maximum ring difference (MRD) will also maintain the same high performance of sensitivity and high peak NECR while at the same time reduces the data size. The extremely-oblique line of response for large axial FOV does not contribute much to the performance of the scanner. The total sensitivity with full MRD increased only 15% than that with about half MRD. The peak NECR was saturated at about half MRD. The entire-body PET scanner promises to provide a large axial FOV and to have sufficient performance values without using the full data.

Integrated numerical modeling of a laser gun injector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, H.; Benson, S.; Bisognano, J.

1993-06-01

CEBAF is planning to incorporate a laser gun injector into the linac front end as a high-charge cw source for a high-power free electron laser and nuclear physics. This injector consists of a DC laser gun, a buncher, a cryounit and a chicane. The performance of the injector is predicted based on integrated numerical modeling using POISSON, SUPERFISH and PARMELA. The point-by-point method incorporated into PARMELA by McDonald is chosen for space charge treatment. The concept of ``conditioning for final bunching`` is employed to vary several crucial parameters of the system for achieving highest peak current while maintaining low emittancemore » and low energy spread. Extensive parameter variation studies show that the design will perform beyond the specifications for FEL operations aimed at industrial applications and fundamental scientific research. The calculation also shows that the injector will perform as an extremely bright cw electron source.« less

Performance of the e2v 1.2 GPix cryogenic camera for the J-PAS 2.5m survey telescope

NASA Astrophysics Data System (ADS)

Robbins, M. S.; Bastable, M.; Bates, A.; Dryer, M.; Eames, S.; Fenemore-Jones, G.; Haddow, G.; Jorden, P. R.; Lane, B.; Marin-Franch, A.; Mortimer, J.; Palmer, I.; Puttay, N.; Renshaw, R.; Smith, M.; Taylor, K.; Tearle, J.; Weston, P.; Wheeler, P.; Worley, J.

2016-08-01

The J-PAS project will perform a five-year survey of the northern sky from a new 2.5m telescope in Teruel, Spain. In this paper the build and factory testing of the commercially supplied cryogenic camera is described. The 1.2 Giga-pixel focal plane is contained within a novel liquid-nitrogen cooled vacuum cryostat, which maintains the flatness for the cooled, 0.45m diameter focal plane to better than 27 μm peak to valley. The cooling system controls the focal plane to a temperature of -100°C with a variation across the focal plane of better than 2.5oC and a stability of better than +/- 0.5 °C over the long periods of operation required. The proximity drive electronics achieves total system level noise performance better than 5 e- from the 224-channel CCD system.

Rationale behind high-dose amoxicillin therapy for acute otitis media due to penicillin-nonsusceptible pneumococci: support from in vitro pharmacodynamic studies.

PubMed Central

Lister, P D; Pong, A; Chartrand, S A; Sanders, C C

1997-01-01

To evaluate whether increased doses of amoxicillin should be used to treat acute pneumococcal otitis media, an in vitro pharmacokinetic model was used to evaluate the killing of pneumococci by amoxicillin when middle ear pharmacokinetics were simulated. Logarithmic-phase cultures were exposed to peak concentrations of 3, 6, and 9 microg of amoxicillin per ml every 12 h, and an elimination half-life of 1.6 h was simulated. Changes in viable bacterial counts were measured over 36 h. All three doses rapidly decreased the viable bacterial counts of penicillin-susceptible strains below the 10-CFU/ml limit of detection by 6 to 10 h and maintained counts below this limit through 36 h. The 3-microg/ml peak dose was much less effective against two of three strains with intermediate penicillin resistance and all three penicillin-resistant strains, with bacterial counts approaching those in drug-free control cultures by 12 h. The 6-microg/ml peak dose completely eliminated two of three strains with intermediate penicillin resistance and maintained viable counts of the other nonsusceptible strains at 1.5 to 2 logs below the initial inoculum through 36 h. The 9-microg/ml peak dose was most effective, completely eliminating all three strains with intermediate penicillin resistance and maintaining the viable counts of the resistant strains at 3 to 4 logs below the original inoculum. The pharmacodynamics observed in this study suggest that peak concentrations of amoxicillin of 6 to 9 microg/ml may be sufficient for the elimination of penicillin-nonsusceptible pneumococcal strains causing otitis media, especially those with intermediate resistance to amoxicillin. In vivo pharmacokinetic studies are needed to determine if these levels can be achieved in middle ear fluid with amoxicillin at 70 to 90 mg/kg/day divided into two daily doses. If these levels are reliably achieved, then clinical studies are warranted. PMID:9303386

Interplay Between Thin Film Ferroelectric Composition, Microstructure and Microwave Phase Shifter Performance

NASA Technical Reports Server (NTRS)

Mueller, Carl H.; VanKeuls, Frederick W.; Romanofsky, Robert R.; Alterovitz, Samuel A.; Miranda, Felix A.

2003-01-01

One of the keys to successfully incorporating ferroelectric films into Ku-band (12 to 18 GHz) phase shifters is to establish the composition, microstructure, and thickness required to meet the tuning needs, and tailor the film properties to meet these needs. Optimal performance is obtained when the film composition and device design are such that the device performance is limited by odd mode dielectric losses, and these losses are minimized as much as possible while still maintaining adequate tunability. The parameters required to maintain device performance will vary slightly depending on composition, but we can conclude that the best tuning-to-loss figures of merit (K-factor) are obtained when there is minimal variation between the in-plane and out-of-plane lattice parameters, and the full-width half maximum values of the BSTO (002) peaks are less than approximately 0.04 deg. We have observed that for phase shifters in which the ferroelectric crystalline quality and thickness are almost identical, higher losses are observed in films with higher BaISr ratios. The best performance was observed in phase shifters with Ba:Sr = 30:70. The superiority of this composition was attributed to several interacting factors: the B a: Sr ratio was such that the Curie temperature (180 K) was far removed from room temperature, the crystalline quality of the film was excellent, and there was virtually no difference between the inplane and out-of-plane lattice parameters of the film.

Effects of sprint interval training and body weight reduction on power to weight ratio in experienced cyclists.

PubMed

Lunn, William R; Finn, Joan A; Axtell, Robert S

2009-07-01

The purpose of this study was to determine the effect of supramaximal sprint interval training (SIT), body weight reduction, and a combination of both treatments on peak and average anaerobic power to weight ratio (PPOan:Wt, APOan:Wt) by manipulating peak and average anaerobic power output (PPOan, APOan) and body weight (BW) in experienced cyclists. Participants (N = 34, age = 38.0 +/- 7.1 years) were assigned to 4 groups for a 10-week study. One group performed twice-weekly SIT sessions on a cycle ergometer while maintaining body weight (SIT). A second group did not perform SIT but intentionally reduced body weight (WR). A third group simultaneously performed SIT sessions and reduced body weight (SIT+WR). A control group cycled in their normal routine and maintained body weight (CON). The 30-second Wingate Test assessed pretest and posttest POan:Wt scores. There was a significant mean increase (p < 0.05) from pretest to posttest in PPOan:Wt and APOan:Wt (W x kg(-1)) scores in both SIT (10.82 +/- 1.71 to 11.92 +/- 1.77 and 8.05 +/- 0.64 to 8.77 +/- 0.64, respectively) and WR (10.33 +/- 2.91 to 11.29 +/- 2.80 and 7.04 +/- 1.45 to 7.62 +/- 1.24, respectively). PPOan and APOan (W) increased significantly only in SIT (753.7 +/- 121.0 to 834.3 +/- 150.1 and 561.3 +/- 62.5 to 612.7 +/- 69.0, respectively). Body weight (kg) decreased significantly in WR and SIT + WR (80.3 +/- 13.7 to 75.3 +/- 11.9 and 78.9 +/- 10.8 to 73.4 +/- 10.8, respectively). The results demonstrate that cyclists can use SIT sessions and body weight reduction as singular training interventions to effect significant increases in anaerobic power to weight ratio, which has been correlated to enhanced aerobic cycling performance. However, the treatments were not effective as combined interventions, as there was no significant change in either PPOan:Wt or APOan:Wt in SIT + WR.

Effects of 30-, 60-, and 90-Day Bed Rest on Postural Control in Men and Women

NASA Technical Reports Server (NTRS)

Esteves, Julie; Taylor, Laura C.; Vanya, Robert D.; Dean, S. Lance; Wood, Scott J.

2011-01-01

INTRODUCTION Head-down-tilt bed rest (HDT) has been used as a safe gr ound-based analog to mimic and develop countermeasures for the physiological effects of spaceflight, including decrements in postural stability. The purpose of this investigation was to characterize the effects of 30-, 60-, and 90-day bed rest on postural control in men and women. METHODS Twenty-nine subjects (18M,11F) underwent 13 days of ambula tory acclimatization and were placed in 6? HDT for 30 (n=12), 60 (n=8), or 90 (n=9) days, followed by 14 days of ambulatory recovery. Computerized dynamic posturography (CDP) was used to assess changes in sensory and motor components of postural control, and recovery after HDT. Sensory Organization Tests (SOTs) objectively evaluate one?s ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Stability during the SOTs was assessed using peak-to-peak sway and convergence toward stability limits to derive an equilibrium score. Motor Control Tests (MCTs) evaluate one?s ability to recover from unexpected support surface perturbations, with performance determined by center-of-pressure path length. Whole-body kinematic data were collected to determine body-sway strategy used to maintain stability during each condition. Baselines were determined pre-HDT. Recovery was tracked post-HDT on days 0, 1, 2, and 4. RESULTS Immediately after HDT, subjects showed decreased performance on most SOTs, primarily on sway-referenced support conditions, typically returning to baseline levels within 4 days. MCT performance was not significantly affected. There were no significant gender or duration differences in performance. Kinematic data revealed a tendency to use ankle strategy to maintain an upright stance during most SOT conditions. Interestingly, six subjects (2M,4F) experienced orthostatic intolerance and were unable to complete day 0 testing. CONCLUSION HDT mimics some un loading mechanisms of spaceflight and elicits orthostatic issues present post-spaceflight (contributing to instability); however, it does not sufficiently address the vestibular dysfunction which occurs post-spaceflight.

A hybrid air conditioner driven by a hybrid solar collector

NASA Astrophysics Data System (ADS)

Al-Alili, Ali

The objective of this thesis is to search for an efficient way of utilizing solar energy in air conditioning applications. The current solar Air Conditioners (A/C)s suffer from low Coefficient of Performance (COP) and performance degradation in hot and humid climates. By investigating the possible ways of utilizing solar energy in air conditioning applications, the bottlenecks in these approaches were identified. That resulted in proposing a novel system whose subsystem synergy led to a COP higher than unity. The proposed system was found to maintain indoor comfort at a higher COP compared to the most common solar A/Cs, especially under very hot and humid climate conditions. The novelty of the proposed A/C is to use a concentrating photovoltaic/thermal collector, which outputs thermal and electrical energy simultaneously, to drive a hybrid A/C. The performance of the hybrid A/C, which consists of a desiccant wheel, an enthalpy wheel, and a vapor compression cycle (VCC), was investigated experimentally. This work also explored the use of a new type of desiccant material, which can be regenerated with a low temperature heat source. The experimental results showed that the hybrid A/C is more effective than the standalone VCC in maintaining the indoor conditions within the comfort zone. Using the experimental data, the COP of the hybrid A/C driven by a hybrid solar collector was found to be at least double that of the current solar A/Cs. The innovative integration of its subsystems allows each subsystem to do what it can do best. That leads to lower energy consumption which helps reduce the peak electrical loads on electric utilities and reduces the consumer operating cost since less energy is purchased during the on peak periods and less solar collector area is needed. In order for the proposed A/C to become a real alternative to conventional systems, its performance and total cost were optimized using the experimentally validated model. The results showed that for an electricity price of 0.12 $/kW-hr, the hybrid solar A/C's cumulative total cost will be less than that of a standard VCC after 17.5 years of operation.

America’s Cup Sailing: Effect of Standing Arm-Cranking (“Grinding”) Direction on Muscle Activity, Kinematics, and Torque Application

PubMed Central

Pearson, Simon N.; Hume, Patria A.; Cronin, John; Slyfield, David

2016-01-01

Grinding is a key physical element in America’s Cup sailing. This study aimed to describe kinematics and muscle activation patterns in relation to torque applied in forward and backward grinding. Ten male America’s Cup sailors (33.6 ± 5.7 years, 97.9 ± 13.4 kg, 186.6 ± 7.4 cm) completed forward and backward grinding on a customised grinding ergometer. In forward grinding peak torque (77 Nm) occurred at 95° (0° = crank vertically up) on the downward section of the rotation at the end of shoulder flexion and elbow extension. Backward grinding torque peaked at 35° (69 Nm) following the pull action (shoulder extension, elbow flexion) across the top of the rotation. During forward grinding, relatively high levels of torque (>50 Nm) were maintained through the majority (72%) of the cycle, compared to 47% for backward grinding, with sections of low torque corresponding with low numbers of active muscles. Variation in torque was negatively associated with forward grinding performance (r = −0.60; 90% CI −0.88 to −0.02), but positively associated with backward performance (r = 0.48; CI = −0.15 to 0.83). Magnitude and distribution of torque generation differed according to grinding direction and presents an argument for divergent training methods to improve forward and backward grinding performance.

GEO light imaging national testbed (GLINT) heliostat design and testing status

NASA Astrophysics Data System (ADS)

Thornton, Marcia A.; Oldenettel, Jerry R.; Hult, Dane W.; Koski, Katrina; Depue, Tracy; Cuellar, Edward L.; Balfour, Jim; Roof, Morey; Yarger, Fred W.; Newlin, Greg; Ramzel, Lee; Buchanan, Peter; Mariam, Fesseha G.; Scotese, Lee

2002-01-01

The GEO Light Imaging National Testbed (GLINT) will use three laser beams producing simultaneous interference fringes to illuminate satellites in geosynchronous earth orbit (GEO). The reflected returns will be recorded using a large 4,000 m2 'light bucket' receiver. This imaging methodology is termed Fourier Telescopy. A major component of the 'light bucket' will be an array of 40 - 80 heliostats. Each heliostat will have a mirrored surface area of 100 m2 mounted on a rigid truss structure which is supported by an A-frame. The truss structure attaches to the torque tube elevation drive and the A-frame structure rests on an azimuth ring that could provide nearly full coverage of the sky. The heliostat is designed to operate in 15 mph winds with jitter of less than 500 microradians peak-to- peak. One objective of the design was to minimize receiver cost to the maximum extent possible while maintaining GLINT system performance specifications. The mechanical structure weights approximately seven tons and is a simple fabricated steel framework. A prototype heliostat has been assembled at Stallion Range Center, White Sands Missile Range, New Mexico and is being tested under a variety of weather and operational conditions. The preliminary results of that testing will be presented as well as some finite element model analyses that were performed to predict the performance of the structure.

Determination of fat-soluble vitamins in vegetable oils through microwave-assisted high-performance liquid chromatography.

PubMed

Carballo, Silvia; Prats, Soledad; Maestre, Salvador; Todolí, José-Luis

2015-04-01

In this manuscript, a study of the effect of microwave radiation on the high-performance liquid chromatography separation of tocopherols and vitamin K1 was conducted. The novelty of the application was the use of a relatively low polarity mobile phase in which the dielectric heating effect was minimized to evaluate the nonthermal effect of the microwave radiation over the separation process. Results obtained show that microwave-assisted high-performance liquid chromatography had a shorter analysis time from 31.5 to 13.3 min when the lowest microwave power was used. Moreover, narrower peaks were obtained; hence the separation was more efficient maintaining or even increasing the resolution between the peaks. This result confirms that the increase in mobile phase temperature is not the only variable for improving the separation process but also other nonthermal processes must intervene. Fluorescence detection demonstrated better signal-to-noise compared to photodiode arrayed detection mainly due to the independent effect of microwave pulses on the baseline noise, but photodiode array detection was finally chosen as it allowed a simultaneous detection of nonfluorescent compounds. Finally, a determination of the content of the vitamin E homologs was carried out in different vegetable oils. Results were coherent with those found in the literature. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Vibrating Jaw Crusher with Auteresonant Electric Motor Drive of Swinging Movement

NASA Astrophysics Data System (ADS)

Zagrivniy, E. A.; Poddubniy, D. A.

2018-01-01

The article relates to a vibrating jaw crusher with pendulum vibrating exciter auteresonant electric motor drive and with elastic element rational force distribution, with limited peak-to-peak swing. Its design and its math model are presented. Also disclosed is the operating principle of a vibrating jaw crusher and the control algorithm for controlling the crushing jaw for maintaining the operating mode at resonant frequency.

Annual peak discharges from small drainage areas in Montana through September 1978

USGS Publications Warehouse

Omang, R.J.; Parrett, C.; Hull, J.A.

1979-01-01

Annual peak stage and discharge data have been collected and tabulated for crest-stage gaging sites in Montana. The crest-stage program was begun in July 1955 to investigate the magnitude and frequency of floods from small drainage areas. The program has expanded from 45 crest-stage gaging stations initially to 173 stations maintained in 1978. Data are tabulated for the period of record. (Woodard-USGS)

A window into occupant-driven energy outcomes: Leveraging sub-metering infrastructure to examine psychosocial factors driving long-term outcomes of short-term competition-based energy interventions

DOE PAGES

Konis, Kyle; Orosz, Michael; Sintov, Nicole

2016-01-07

Competition-based “energy saving” interventions are increasingly promoted as an effective strategy for reducing energy consumption in buildings with large occupant controlled electrical loads. However, the factors that drive energy savings in such interventions are not well understood, nor are the impacts of short-term competitions on long-term energy performance. A total of 39 8-occupant suites in a freshman residence hall were instrumented with “smart” electric meters, which recorded circuit-level electricity consumption at 15-minute intervals. During a three-week Fall 2014 competition, suites competed to reduce their overall electricity demand and achieved a 6.4% reduction in whole-building demand overall and a 12% reductionmore » during hours of peak demand (from 12:00 to 19:00), despite peak seasonal temperatures and all-time record electricity demand. Analysis incorporating weather-normalized HVAC demand after the competition showed a significant “rebound” for a large portion of the suites (19), however 12 suites made further reductions, and the remainder maintained demand at the competition level. As a result, we compared energy data with self-reported survey data and identified self-efficacy beliefs, pro-environmental behaviors, and sense of affiliation with other residents of the hall as key factors distinguishing the suites with the greatest and most persistent reductions in demand from suites that maintained or increased demand.« less

Streamflow and Selected Precipitation Data for Yucca Mountain Region, Southern Nevada and Eastern California, Water Years 1986-90

USGS Publications Warehouse

Kane, Thomas G.; Bauer, David J.; Martinez, Clair M.

1994-01-01

Streamflow and precipitation data collected at and near Yucca Mountain, Nevada, during water years 1986-90 are presented in this report. The data were collected and compiled as part of the studies by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, to characterize surface-water hydrology in the Yucca Mountain area. Streamflow data include daily-mean discharges and peak discharges at 5 continuous-record gaging stations, and peak discharges at 10 crest-stage, partial-record stations and 2 miscellaneous sites. Precipitation data include cumulative totals at 20 stations maintained by the U.S. Geological Survey and daily totals at 15 stations maintained by the Weather Service Nuclear Support Office, National Oceanic and Atmospheric Administration.

Chloride concentrations, loads, and yields in four watersheds along Interstate 95, southeastern Connecticut, 2008-11: factors that affect peak chloride concentrations during winter storms

USGS Publications Warehouse

Brown, Craig J.; Mullaney, John R.; Morrison, Jonathan; Martin, Joseph W.; Trombley, Thomas J.

2015-07-01

The addition of a lane mile in both directions on I–95 would result in an estimate of approximately 2 to 11 percent increase in Cl- input from deicers applied to I–95 and other roads maintained by Connecticut Department of Transportation. The largest estimated increase in Cl- load was in the watersheds with the greatest number miles of I–95 corridor relative to the total lane miles maintained by Connecticut Department of Transportation. On the basis of these estimates and the estimated peak Cl- concentrations during the study period, it is unlikely that the increased use of deicers on the additional lanes would lead to Cl- concentrations that exceed the aquatic habitat criteria.

TEST-retest reliability of kinetic variables measured on campus board in sport climbers.

PubMed

Abreu, Edgardo Alvares de Campos; Araújo, Sílvia Ribeiro Santos; Cançado, Gustavo Henrique da Cunha Peixoto; Andrade, André Gustavo Pereira de; Chagas, Mauro Heleno; Menzel, Hans-Joachim Karl

2018-05-16

Sport climbers frequently use campus board (CB) to improve their upper limb strength under similar conditions of high-difficulty sport climbing routes. The objective of this study was to assess the test-retest reliability of peak force and impulse measured using a CB instrumented with two load cells on starting holds. The same evaluator examined 22 climbers on two days with 48 h between the assessments. The participants performed five concentric lunges (CL) and five lunges with stretch-shortening cycle with 1 min intervals between repetitions and 10 min between exercises. All variables were associated with significant intraclass correlation coefficient (ICC) values (p = 0.001), and none variable showed systematic errors (p > 0.05). Peak force ICC was higher than 0.88, and the standard error of measurement (SEM%) was less than 5%. Impulse ICC for the CL was greater than 0.90, and the SEM% was less than 14%. We conclude that the kinetic variables measured using the CB were reliable. The ability of the hands to maintain contact with the holds (peak force) and the abilities of the arms and shoulders vertically move the centre of mass (impulse) should be taken into account by coaches on CB training prescription as well for further research.

Comparison of Exercise Performance in Recreationally Active and Masters Athlete Women.

PubMed

Stone, Matthew S; Glenn, Jordan M; Vincenzo, Jennifer L; Gray, Michelle

2018-02-01

Stone, MS, Glenn, JM, Vincenzo, JL, and Gray, M. Comparison of exercise performance in recreationally active and masters athlete women. J Strength Cond Res 32(2): 565-571, 2018-Master athletes (MA) are an understudied, ever-growing cohort. As such, it is important to examine how age affects muscular power and fatigability. Of particular interest is muscular power maintenance and fatigue mitigation of MA compared with young, healthy adults. The purpose of this investigation was to examine the differences in peak power, average power, total work (WRK), and fatigue index (FI) between recreationally active (RA) younger adults and female MA during anaerobic cycling exercise. Two groups, RA (n = 15; 20.6 ± 0.8 years) and MA (n = 17; 50.5 ± 8.6 years), participated in this study. Peak power, APWR, WRK, and FI were measured during a 30-second Wingate maximum anaerobic cycling protocol at a predetermined resistance of 7.5% body mass. Peak power (p = 0.92; RA: 654.1 ± 114.5 W; MA: 658.6 ± 147.6 W), APWR (p = 0.09; RA: 429.8 ± 73.3 W; MA: 384 ± 73.8 W), WRK (p = 0.09; RA: 12,894.3 ± 2,198.3 J; MA: 18,044.3 ± 27,184.9 J), and FI (p = 0.30; RA: 11.8 ± 4.1 W·s; MA: 14 ± 5.2 W·s) were not significantly different between groups. Master athletes produce power and WRK comparable to rates of fatigue among RA. This suggests that MA can maintain physical ability similar to RA in multiple parameters of high-intensity exercise while mitigating fatigue comparably. These data allow for advancements in exercise training and performance outcomes in MA populations. Further research within the MA population is warranted regarding other aspects of exercise and sport performance.

Partial maintenance of auditory-based cognitive training benefits in older adults

PubMed Central

Anderson, Samira; White-Schwoch, Travis; Choi, Hee Jae; Kraus, Nina

2014-01-01

The potential for short-term training to improve cognitive and sensory function in older adults has captured the public’s interest. Initial results have been promising. For example, eight weeks of auditory-based cognitive training decreases peak latencies and peak variability in neural responses to speech presented in a background of noise and instills gains in speed of processing, speech-in-noise recognition, and short-term memory in older adults. But while previous studies have demonstrated short-term plasticity in older adults, we must consider the long-term maintenance of training gains. To evaluate training maintenance, we invited participants from an earlier training study to return for follow-up testing six months after the completion of training. We found that improvements in response peak timing to speech in noise and speed of processing were maintained, but the participants did not maintain speech-in-noise recognition or memory gains. Future studies should consider factors that are important for training maintenance, including the nature of the training, compliance with the training schedule, and the need for booster sessions after the completion of primary training. PMID:25111032

Numerical investigation of a laser gun injector at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byung Yunn; Charles Sinclair; David Neuffer

1993-08-23

A laser gun injector is being developed based on the superconducting rf technologies established at CEBAF. This injector will serve as a high charge cw source for a high power free electron laser. It consists of a dc laser gun, a buncher, a cryounit and a chicane. Its space-charge-dominated performance has been thoroughly investigated using the time-consuming but more appropriate point-by-point space charge calculation method in PARMELA. The notion of ``conditioning for final bunching'' will be introduced. This concept has been built into the code and has greatly facilitated the optimization of the whole system to achieve the highest possiblemore » peak current while maintaining low emittance and low energy spread. Extensive parameter variation studies have shown that the design will perform better than the specifications.« less

Multiple-dose pharmacokinetics of daptomycin during continuous venovenous haemodiafiltration.

PubMed

Wenisch, Judith M; Meyer, Brigitte; Fuhrmann, Valentin; Saria, Katrin; Zuba, Clara; Dittrich, Peter; Thalhammer, Florian

2012-04-01

Daptomycin is bactericidal against Gram-positive bacteria, with peak-dependent effect but trough-dependent toxicity. This study was performed to develop dosing recommendations in continuous venovenous haemodiafiltration (CVVHDF). Nine critically ill patients in intensive care units of the Medical University Hospital of Vienna, requiring CVVHDF due to acute renal failure and antimicrobial treatment, were included. Blood and effluent samples were collected over 72 h to determine daptomycin concentrations by HPLC. Pharmacokinetic parameters were based on 10 sampling timepoints during the first 24 h, and peak and trough samples thereafter. An open two-compartment model was fitted to each subject's plasma concentration-time data. Simulations of serum concentration-time profiles after different doses and intervals were performed using ADAPT 5. Peak plasma concentrations with 6 mg/kg daptomycin were 62.2 ± 16.2, 66.1 ± 17.3 and 78.5 ± 22.1 mg/L on days 1, 2 and 3, respectively. The total clearance was 6.1 ± 4.9 mL/min, and the elimination half-life was 17.8 ± 9.7 h. Daptomycin was filtrated and could therefore be measured in the effluent. Protein binding was lower than that seen in healthy volunteers. The unbound fraction was 16 ± 4.5%. All subjects maintained trough serum concentrations above 4 mg/L, at which relevant pathogens are considered daptomycin-susceptible. Accumulation resulted when daptomycin was given every 24 h. Simulation of 8 mg/kg daptomycin given every 48 h resulted in adequate levels without accumulation. We recommend 8 mg/kg daptomycin every 48 h in patients on CVVHDF and therapeutic drug monitoring, if possible.

The relationship between gas fill density and hohlraum drive performance at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Hall, G. N.; Jones, O. S.; Strozzi, D. J.; Moody, J. D.; Turnbull, D.; Ralph, J.; Michel, P. A.; Hohenberger, M.; Moore, A. S.; Landen, O. L.; Divol, L.; Bradley, D. K.; Hinkel, D. E.; Mackinnon, A. J.; Town, R. P. J.; Meezan, N. B.; Berzak Hopkins, L.; Izumi, N.

2017-05-01

Indirect drive inertial confinement fusion experiments were conducted at the National Ignition Facility to investigate the performance of the hohlraum drive as a function of hohlraum gas fill density by imploding high-density-carbon capsules using a 2-shock laser pulse. Measurements characterized the backscatter behavior, the production of hot electrons, the motion and brightness of the laser spots on the hohlraum wall, and the efficiency of the hohlraum x-ray drive as a function of gas fill density ρgf between 0.03 mg/cc ("near vacuum") and 1.6 mg/cc. For hohlraums with ρgf up to 0.85 mg/cc, very little stimulated Raman backscatter (SRS) was observed. For higher ρgf, significant SRS was produced and was observed to occur during the rise to peak laser power and throughout the main pulse. The efficiency with which laser energy absorbed by the hohlraum is converted into drive energy was measured to be the same for ρgf ≥ 0.6 mg/cc once the laser reached peak power. However, for the near vacuum case, the absorbed energy was converted to drive energy more efficiently throughout the pulse and maintained an efficiency ˜10% higher than the gas filled hohlraums throughout the main pulse.

The relationship between gas fill density and hohlraum drive performance at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, G. N.; Jones, O. S.; Strozzi, D. J.

Indirect drive inertial confinement fusion experiments were conducted at the National Ignition Facility to investigate the performance of the hohlraum drive as a function of hohlraum gas fill density by imploding high-density-carbon capsules using a 2-shock laser pulse. Our ,easurements characterize the backscatter behavior, the production of hot electrons, the motion and brightness of the laser spots on the hohlraum wall, and the efficiency of the hohlraum x-ray drive as a function of gas fill density ρ gf between 0.03 mg/cc (“near vacuum”) and 1.6 mg/cc. For hohlraums with ρ gf up to 0.85 mg/cc, very little stimulated Raman backscattermore » (SRS) was observed. Furthermore, for higher ρ gf, significant SRS was produced and was observed to occur during the rise to peak laser power and throughout the main pulse. The efficiency with which laser energy absorbed by the hohlraum is converted into drive energy was measured to be the same for ρ gf ≥ 0.6 mg/cc once the laser reached peak power. But, for the near vacuum case, the absorbed energy was converted to drive energy more efficiently throughout the pulse and maintained an efficiency ~10% higher than the gas filled hohlraums throughout the main pulse.« less

Motion-compensated optical coherence tomography using envelope-based surface detection and Kalman-based prediction

NASA Astrophysics Data System (ADS)

Irsch, Kristina; Lee, Soohyun; Bose, Sanjukta N.; Kang, Jin U.

2018-02-01

We present an optical coherence tomography (OCT) imaging system that effectively compensates unwanted axial motion with micron-scale accuracy. The OCT system is based on a swept-source (SS) engine (1060-nm center wavelength, 100-nm full-width sweeping bandwidth, and 100-kHz repetition rate), with axial and lateral resolutions of about 4.5 and 8.5 microns respectively. The SS-OCT system incorporates a distance sensing method utilizing an envelope-based surface detection algorithm. The algorithm locates the target surface from the B-scans, taking into account not just the first or highest peak but the entire signature of sequential A-scans. Subsequently, a Kalman filter is applied as predictor to make up for system latencies, before sending the calculated position information to control a linear motor, adjusting and maintaining a fixed system-target distance. To test system performance, the motioncorrection algorithm was compared to earlier, more basic peak-based surface detection methods and to performing no motion compensation. Results demonstrate increased robustness and reproducibility, particularly noticeable in multilayered tissues, while utilizing the novel technique. Implementing such motion compensation into clinical OCT systems may thus improve the reliability of objective and quantitative information that can be extracted from OCT measurements.

The relationship between gas fill density and hohlraum drive performance at the National Ignition Facility

DOE PAGES

Hall, G. N.; Jones, O. S.; Strozzi, D. J.; ...

2017-05-11

Indirect drive inertial confinement fusion experiments were conducted at the National Ignition Facility to investigate the performance of the hohlraum drive as a function of hohlraum gas fill density by imploding high-density-carbon capsules using a 2-shock laser pulse. Our ,easurements characterize the backscatter behavior, the production of hot electrons, the motion and brightness of the laser spots on the hohlraum wall, and the efficiency of the hohlraum x-ray drive as a function of gas fill density ρ gf between 0.03 mg/cc (“near vacuum”) and 1.6 mg/cc. For hohlraums with ρ gf up to 0.85 mg/cc, very little stimulated Raman backscattermore » (SRS) was observed. Furthermore, for higher ρ gf, significant SRS was produced and was observed to occur during the rise to peak laser power and throughout the main pulse. The efficiency with which laser energy absorbed by the hohlraum is converted into drive energy was measured to be the same for ρ gf ≥ 0.6 mg/cc once the laser reached peak power. But, for the near vacuum case, the absorbed energy was converted to drive energy more efficiently throughout the pulse and maintained an efficiency ~10% higher than the gas filled hohlraums throughout the main pulse.« less

Feasibility of using a reliable automated Doppler flow velocity measurements for research and clinical practices

NASA Astrophysics Data System (ADS)

Zolgharni, Massoud; Dhutia, Niti M.; Cole, Graham D.; Willson, Keith; Francis, Darrel P.

2014-03-01

Echocardiographers are often unkeen to make the considerable time investment to make additional multiple measurements of Doppler velocity. Main hurdle to obtaining multiple measurements is the time required to manually trace a series of Doppler traces. To make it easier to analyse more beats, we present an automated system for Doppler envelope quantification. It analyses long Doppler strips, spanning many heartbeats, and does not require the electrocardiogram to isolate individual beats. We tested its measurement of velocity-time-integral and peak-velocity against the reference standard defined as the average of three experts who each made three separate measurements. The automated measurements of velocity-time-integral showed strong correspondence (R2 = 0.94) and good Bland-Altman agreement (SD = 6.92%) with the reference consensus expert values, and indeed performed as well as the individual experts (R2 = 0.90 to 0.96, SD = 5.66% to 7.64%). The same performance was observed for peak-velocities; (R2 = 0.98, SD = 2.95%) and (R2 = 0.93 to 0.98, SD = 2.94% to 5.12%). This automated technology allows <10 times as many beats to be acquired and analysed compared to the conventional manual approach, with each beat maintaining its accuracy.

Annual peak discharges from small drainage areas in Montana through September 1980

USGS Publications Warehouse

Omang, R.J.; Parrett, Charles; Hull, J.A.

1955-01-01

Annual peak stage and discharge data have been collected and tabulated for crest-stage gaging sites in Montana. The crest-stage program was begun in July 1955 to investigate the magnitude and frequency of floods from small drainage areas. The program has expanded from 45 crest-stage gaging stations initially to 172 stations maintained in 1980. Data in the report are tabulated for the period of record. (USGS)

Annual peak discharges from small drainage areas in Montana through September 1979

USGS Publications Warehouse

Omang, R.J.; Parrett, C.; Hull, J.A.

1955-01-01

Annual peak stage and discharge data have been collected and tabulated for crest-stage gaging sites in Montana. The crest-stage program was begun in July 1955 to investigate the magnitude and frequency of floods from small drainage areas. The program has expanded from 45 crest-stage gaging stations initially to 173 stations maintained in 1979. Data in the report are tabulated for the period of record. (USGS)

Analysis of the change in peak corneal temperature during excimer laser ablation in porcine eyes

NASA Astrophysics Data System (ADS)

Mosquera, Samuel Arba; Verma, Shwetabh

2015-07-01

The objective is to characterize the impact of different ablation parameters on the thermal load during corneal refractive surgery by means of excimer laser ablation on porcine eyes. One hundred eleven ablations were performed in 105 porcine eyes. Each ablation was recorded using infrared thermography and analyzed mainly based on the two tested local frequencies (40 Hz, clinical local frequency; 1000 Hz, no local frequency). The change in peak corneal temperature was analyzed with respect to varying ablation parameters [local frequency, system repetition rate, pulse energy, optical zone (OZ) size, and refractive correction]. Transepithelial ablations were also compared to intrastromal ablations. The average of the baseline temperature across all eyes was 20.5°C±1.1 (17.7°C to 22.2°C). Average of the change in peak corneal temperature for all clinical local frequency ablations was 5.8°C±0.8 (p=3.3E-53 to baseline), whereas the average was 9.0°C±1.5 for all no local frequency ablations (p=1.8E-35 to baseline, 1.6E-16 to clinical local frequency ablations). A logarithmic relationship was observed between the changes in peak corneal temperature with increasing local frequency. For clinical local frequency, change in peak corneal temperature was comparatively flat (r2=0.68 with a range of 1.5°C) with increasing system repetition rate and increased linearly with increasing OZ size (r2=0.95 with a range of 2.4°C). Local frequency controls help maintain safe corneal temperature increase during excimer laser ablations. Transepithelial ablations induce higher thermal load compared to intrastromal ablations, indicating a need for stronger thermal controls in transepithelial refractive procedures.

Seasonal asthma in Melbourne, Australia, and some observations on the occurrence of thunderstorm asthma and its predictability

PubMed Central

Sutherland, Michael F.; Johnston, Fay H.; Lampugnani, Edwin R.; McCarthy, Michael A.; Jacobs, Stephanie J.; Pezza, Alexandre B.; Newbigin, Edward J.

2018-01-01

We examine the seasonality of asthma-related hospital admissions in Melbourne, Australia, in particular the contribution and predictability of episodic thunderstorm asthma. Using a time-series ecological approach based on asthma admissions to Melbourne metropolitan hospitals, we identified seasonal peaks in asthma admissions that were centred in late February, June and mid-November. These peaks were most likely due to the return to school, winter viral infections and seasonal allergies, respectively. We performed non-linear statistical regression to predict daily admission rates as functions of the seasonal cycle, weather conditions, reported thunderstorms, pollen counts and air quality. Important predictor variables were the seasonal cycle and mean relative humidity in the preceding two weeks, with higher humidity associated with higher asthma admissions. Although various attempts were made to model asthma admissions, none of the models explained substantially more variation above that associated with the annual cycle. We also identified a list of high asthma admissions days (HAADs). Most HAADs fell in the late-February return-to-school peak and the November allergy peak, with the latter containing the greatest number of daily admissions. Many HAADs in the spring allergy peak may represent episodes of thunderstorm asthma, as they were associated with rainfall, thunderstorms, high ambient grass pollen levels and high humidity, a finding that suggests thunderstorm asthma is a recurrent phenomenon in Melbourne that occurs roughly once per five years. The rarity of thunderstorm asthma events makes prediction challenging, underscoring the importance of maintaining high standards of asthma management, both for patients and health professionals, especially during late spring and early summer. PMID:29649224

High-Intensity Jump Training Is Tolerated during 60 Days of Bed Rest and Is Very Effective in Preserving Leg Power and Lean Body Mass: An Overview of the Cologne RSL Study.

PubMed

Kramer, Andreas; Kümmel, Jakob; Mulder, Edwin; Gollhofer, Albert; Frings-Meuthen, Petra; Gruber, Markus

2017-01-01

Space agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance. 23 male participants (29±6 years, 181±6 cm, 77±7 kg) were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT), and a 15-day ambulatory recovery phase. Participants were randomly allocated to the jump training group (JUMP, n = 12) or the control group (CTRL, n = 11). A typical training session consisted of 4x10 countermovement jumps and 2x10 hops in a sledge jump system. The training group had to complete 5-6 sessions per week. Peak force for the reactive hops (3.6±0.4 kN) as well as jump height (35±4 cm) and peak power (3.1±0.2 kW) for the countermovement jumps could be maintained over the 60 days of HDT. Lean body mass decreased in CTRL but not in JUMP (-1.6±1.9 kg and 0±1.0 kg, respectively, interaction effect p = 0.03). Resting heart rate during recovery was significantly increased for CTRL but not for JUMP (interaction effect p<0.001). Participants tolerated the near-daily high-intensity jump training and maintained high peak forces and high power output during 60 days of bed rest. The countermeasure was effective in preserving lean body mass and partly preventing cardiac deconditioning with only several minutes of training per day.

Restoring Natural Streamflow Variability by Modifying Multi-purpose Reservoir Operation

NASA Astrophysics Data System (ADS)

Shiau, J.

2010-12-01

Multi-purpose reservoirs typically provide benefits of water supply, hydroelectric power, and flood mitigation. Hydroelectric power generations generally do not consume water. However, temporal distribution of downstream flows is highly changed due to hydro-peaking effects. Associated with offstream diversion of water supplies for municipal, industrial, and agricultural requirements, natural streamflow characteristics of magnitude, duration, frequency, timing, and rate of change is significantly altered by multi-purpose reservoir operation. Natural flow regime has long been recognized a master factor for ecosystem health and biodiversity. Restoration of altered flow regime caused by multi-purpose reservoir operation is the main objective of this study. This study presents an optimization framework that modifying reservoir operation to seeking balance between human and environmental needs. The methodology presented in this study is applied to the Feitsui Reservoir, located in northern Taiwan, with main purpose of providing stable water-supply and auxiliary purpose of electricity generation and flood-peak attenuation. Reservoir releases are dominated by two decision variables, i.e., duration of water releases for each day and percentage of daily required releases within the duration. The current releasing policy of the Feitsui Reservoir releases water for water-supply and hydropower purposes during 8:00 am to 16:00 pm each day and no environmental flows releases. Although greater power generation is obtained by 100% releases distributed within 8-hour period, severe temporal alteration of streamflow is observed downstream of the reservoir. Modifying reservoir operation by relaxing these two variables and reserve certain ratio of streamflow as environmental flow to maintain downstream natural variability. The optimal reservoir releasing policy is searched by the multi-criterion decision making technique for considering reservoir performance in terms of shortage ratio and power generation and downstream hydrologic alterations in terms of ecological relevant indicators. The results show that the proposed methodology can mitigate hydro-peaking effects on natural variability, while maintains efficient reservoir operation.

A Compton scatter attenuation gamma ray spectrometer

NASA Technical Reports Server (NTRS)

Austin, W. E.

1972-01-01

A Compton scatter attenuation gamma ray spectrometer conceptual design is discussed for performing gamma spectral measurements in monodirectional gamma fields from 100 R per hour to 1,000,000 R per hour. Selectable Compton targets are used to scatter gamma photons onto an otherwise heavily shielded detector with changeable scattering efficiencies such that the count rate is maintained between 500 and 10,000 per second. Use of two sum-Compton coincident detectors, one for energies up to 1.5 MeV and the other for 600 keV to 10 MeV, will allow good peak to tail pulse height ratios to be obtained over the entire spectrum and reduces the neutron recoil background rate.

Effect of lactate consumption on exercise performance.

PubMed

Bryner, R W; Hornsby, W G; Chetlin, R; Ullrich, I H; Yeater, R A

1998-06-01

Maintenance of plasma glucose is important in endurance performance. Gluconeogenesis or carbohydrate ingestion maintain glucose after hepatic glycogen depletion. Lactate may also serve as a gluconeogenic precursor as well as a blood buffer. To determine if an 8% carbohydrate (CHO) sports drink with and without a 2% lactate (L) solution increased endurance performance, peak power, and delayed blood acidosis, seven trained cyclists participated in a double-blind randomized study (6 males and 1 female) performed a bicycle test to determine max VO2max HR and the HR associated with the first respiratory exchange ratio (RER) value greater than 1.0 (target HR). Four bicycle rides to exhaustion, separated by one week, were done at a constant workload at a HR 10 beats below each subject's target HR. After a 12-hour fast, subjects received 100 g CHO 2-3 hrs before each test. Mean exercise heart rate was 86-87% max HR. During the final 30 s of each ride the Wingate power test was performed. Subjects consumed either (placebo, 2% L, 8% CHO or 8% CHO plus 2% L) every 20 min. Blood samples were collected before, every 30 min during and immediately following the test. No significant differences were observed in total time (placebo: 95.3 +/- 25.8, 2% lactate: 95.7 +/- 30.0, 8% CHO: 105.2 +/- 37.2, 8% CHO + 2% lactate: 89.0 +/- 28.1 min) or peak power (placebo: 798.2 +/- 241.1, 2% L: 750.1 +/- 279.2, 8% CHO: 789.4 +/- 353.5, 8% CHO + 2% L: 716.3 +/- 331.3 Watts) among drinks. There were no differences in insulin, glucose, pH and HCO3- after the power tests among the drinks. Exercise performance is unaffected by oral supplementation with lactate.

Combined aerobic and resistance training improves physical capacity in women treated for gynecological cancer.

PubMed

Hausmann, F; Iversen, V V; Kristoffersen, M; Gundersen, H; Johannsson, E; Vika, M

2018-04-14

The purpose of this study was to evaluate the effects of 16 weeks combined aerobic and resistance training, twice a week, on the physical performance in women treated for gynecological cancer. Sixty women (56.9 ± 13.3 years) who had completed curative treatment for gynecological cancer were divided into two groups: a physical training group (PT) (n = 29) or a control group (C) (n = 31). The PT group performed two sessions of combined aerobic and resistance training weekly for 16 weeks. Peak oxygen consumption (V̇O 2peak ) and one repetition maximum (1RM) of leg press, leg extension, and chest press were measured before group assignment, after 16 weeks and at the 1-year follow-up. A significant increase in V̇O 2peak (ml min -1  kg -1 ) (29.7 ± 8.0 vs. 31.3 ± 8.3, p = .009), leg press (kg) (113.0 ± 27.3 vs. 116.7 ± 29.2, p = .047), leg extension (kg) (44.2 ± 10.1 vs. 48.0 ± 10.6, p < .001), and chest press (kg) (24.5 ± 7.5 vs. 26.9 ± 8.2, p = .001) was seen in the PT group from pre- to post-measurement. The PT group maintained the improved aerobic condition and muscle strength 1 year after the training intervention. In the C group, there were no significant differences between pre- and post-measurements, but a significant decrease (28.2 ± 7.5 vs. 27.0 ± 7.3, p = .040) in the V̇O 2peak from post to 1-year follow-up measurements. Combined aerobic and resistance training twice a week in 16 weeks improves V̇O 2peak and maximal strength in women treated for gynecological cancer. The training effects were sustained after 1 year in the PT group.

Experimental investigation of time dependent behavior of welded Topopah Spring Tuff

NASA Astrophysics Data System (ADS)

Ma, Lumin

Four types of laboratory tests have been performed. Specimens were attained from four lithophysal zones of the welded Topopah Spring Tuff unit at Yucca Mountain, Nevada: upper lithophysal, middle nonlithophysal, lower lithophysal and lower nonlithophysal zones. Two types of tests are conducted to study time-dependent behavior: constant strain rate and creep tests. Sixty-five specimens from the middle nonlithophysal zone were tested at six strain rates: 10-2, 10-4, 10-5, 10-6, 10-7, and 10-8 s-1. Test durations range from 2 seconds to 7 days. Fourteen specimens from middle nonlithophysal, lower lithophysal and lower nonlithophysal zones are creep tested by incremental stepwise loading. All the tests are conducted under uniaxial compression at room temperature and humidity. Specimens exhibit extremely brittle fracture and fail by axial splitting, and show very little dilatancy if any. It is assumed that microfracturing dominates the inelastic deformation and failure of the tuff. Nonlinear regression is applied to the results of the constant strain rate tests to estimate the relations between peak strength, peak axial strain, secant modulus and strain rate. All three these parameters decrease with a decrease of strain rate and follow power functions: sigmapeak = 271.37 3˙0.0212 0.0212, epsilonpeak = 0.006 3˙0.0083 , ES = 41985.4 3˙0.015 . Secant modulus is introduced mainly as a tool to analyze strain rate dependent axial strain. Two threshold stresses define creep behavior. Below about 50% of peak strength, a specimen does not creep. Above about 94% of peak strength, a specimen creeps at an accelerating rate. Between the two threshold stresses, a power law relates strain rate and stress. One hundred fifty-eight Brazilian (Indirect tensile splitting) tests have been performed at six different constant strain rates. Nineteen lithophysal specimens were tested in uniaxial compression to study their fracture pattern. These specimens have a far less brittle failure mode. They slowly crumble, collapse, and maintain considerable relative strength beyond the peak. Due to the presence of multiple relatively large lithophysal cavities, they are far weaker and softer than the nonlithophysal specimens.

Sub-MW peak power diffraction-limited chirped-pulse monolithic Yb-doped tapered fiber amplifier.

PubMed

Bobkov, Konstantin; Andrianov, Alexey; Koptev, Maxim; Muravyev, Sergey; Levchenko, Andrei; Velmiskin, Vladimir; Aleshkina, Svetlana; Semjonov, Sergey; Lipatov, Denis; Guryanov, Alexey; Kim, Arkady; Likhachev, Mikhail

2017-10-30

We demonstrate a novel amplification regime in a counter-pumped, relatively long (2 meters), large mode area, highly Yb-doped and polarization-maintaining tapered fiber, which offers a high peak power directly from the amplifier. The main feature of this regime is that the amplifying signal propagates through a thin part of the tapered fiber without amplification and experiences an extremely high gain in the thick part of the tapered fiber, where most of the pump power is absorbed. In this regime, we have demonstrated 8 ps pulse amplification to a peak power of up to 0.76 MW, which is limited by appearance of stimulated Raman scattering. In the same regime, 28 ps chirped pulses are amplified to a peak power of 0.35 MW directly from the amplifier and then compressed with 70% efficiency to 315 ± 10 fs, corresponding to an estimated peak power of 22 MW.

Efficiency Enhancement of Pico-cell Base Station Power Amplifier MMIC in Gallium Nitride HFET Technology Using the Doherty technique

NASA Astrophysics Data System (ADS)

Seneviratne, Sashieka

With the growth of smart phones, the demand for more broadband, data centric technologies are being driven higher. As mobile operators worldwide plan and deploy 4th generation (4G) networks such as LTE to support the relentless growth in mobile data demand, the need for strategically positioned pico-sized cellular base stations known as 'pico-cells' are gaining traction. In addition to having to design a transceiver in a much compact footprint, pico-cells must still face the technical challenges presented by the new 4G systems, such as reduced power consumptions and linear amplification of the signals. The RF power amplifier (PA) that amplifies the output signals of 4G pico-cell systems face challenges to minimize size, achieve high average efficiencies and broader bandwidths while maintaining linearity and operating at higher frequencies. 4G standards as LTE use non-constant envelope modulation techniques with high peak to average ratios. Power amplifiers implemented in such applications are forced to operate at a backed off region from saturation. Therefore, in order to reduce power consumption, a design of a high efficiency PA that can maintain the efficiency for a wider range of radio frequency signals is required. The primary focus of this thesis is to enhance the efficiency of a compact RF amplifier suitable for a 4G pico-cell base station. For this aim, an integrated two way Doherty amplifier design in a compact 10mm x 11.5mm2 monolithic microwave integrated circuit using GaN device technology is presented. Using non-linear GaN HFETs models, the design achieves high effi-ciencies of over 50% at both back-off and peak power regions without compromising on the stringent linearity requirements of 4G LTE standards. This demonstrates a 17% increase in power added efficiency at 6 dB back off from peak power compared to conventional Class AB amplifier performance. Performance optimization techniques to select between high efficiency and high linearity operation are also presented. Overall, this thesis demonstrates the feasibility of an integrated HFET Doherty amplifier for LTE band 7 which entails the frequencies from 2.62-2.69GHz. The realization of the layout and various issues related to the PA design is discussed and attempted to be solved.

Pulmonary arterial hypertension reduces energy efficiency of right, but not left, rat ventricular trabeculae.

PubMed

Pham, Toan; Nisbet, Linley; Taberner, Andrew; Loiselle, Denis; Han, June-Chiew

2018-04-01

Pulmonary arterial hypertension (PAH) triggers right ventricle (RV) hypertrophy and left ventricle (LV) atrophy, which progressively leads to heart failure. We designed experiments under conditions mimicking those encountered by the heart in vivo that allowed us to investigate whether consequent structural and functional remodelling of the ventricles affects their respective energy efficiencies. We found that peak work output was lower in RV trabeculae from PAH rats due to reduced extent and velocity of shortening. However, their suprabasal enthalpy was unaffected due to increased activation heat, resulting in reduced suprabasal efficiency. There was no effect of PAH on LV suprabasal efficiency. We conclude that the mechanism underlying the reduced energy efficiency of hypertrophied RV tissues is attributable to the increased energy cost of Ca 2+ cycling, whereas atrophied LV tissues still maintain normal mechano-energetic performance. Pulmonary arterial hypertension (PAH) greatly increases the afterload on the right ventricle (RV), triggering RV hypertrophy, which progressively leads to RV failure. In contrast, the disease reduces the passive filling pressure of the left ventricle (LV), resulting in LV atrophy. We investigated whether these distinct structural and functional consequences to the ventricles affect their respective energy efficiencies. We studied trabeculae isolated from both ventricles of Wistar rats with monocrotaline-induced PAH and their respective Control groups. Trabeculae were mounted in a calorimeter at 37°C. While contracting at 5 Hz, they were subjected to stress-length work-loops over a wide range of afterloads. They were subsequently required to undergo a series of isometric contractions at various muscle lengths. In both protocols, stress production, length change and suprabasal heat output were simultaneously measured. We found that RV trabeculae from PAH rats generated higher activation heat, but developed normal active stress. Their peak external work output was lower due to reduced extent and velocity of shortening. Despite lower peak work output, suprabasal enthalpy was unaffected, thereby rendering suprabasal efficiency lower. Crossbridge efficiency, however, was unaffected. In contrast, LV trabeculae from PAH rats maintained normal mechano-energetic performance. Pulmonary arterial hypertension reduces the suprabasal energy efficiency of hypertrophied right ventricular tissues as a consequence of the increased energy cost of Ca 2+ cycling. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Relationships Between Potentiation Effects After Ballistic Half-Squats and Bilateral Symmetry.

PubMed

Suchomel, Timothy J; Sato, Kimitake; DeWeese, Brad H; Ebben, William P; Stone, Michael H

2016-05-01

The purposes of this study were to examine the effect of ballistic concentric-only half-squats (COHS) on subsequent squat-jump (SJ) performances at various rest intervals and to examine the relationships between changes in SJ performance and bilateral symmetry at peak performance. Thirteen resistance-trained men performed an SJ immediately and every minute up to 10 min on dual force plates after 2 ballistic COHS repetitions at 90% of their 1-repetition-maximum COHS. SJ peak force, peak power, net impulse, and rate of force development (RFD) were compared using a series of 1-way repeated-measures ANOVAs. The percent change in performance at which peak performance occurred for each variable was correlated with the symmetry index scores at the corresponding time point using Pearson correlation coefficients. Statistical differences in peak power (P = .031) existed between rest intervals; however, no statistically significant pairwise comparisons were present (P > .05). No statistical differences in peak force (P = .201), net impulse (P = .064), and RFD (P = .477) were present between rest intervals. The relationships between changes in SJ performance and bilateral symmetry after the rest interval that produced the greatest performance for peak force (r = .300, P = .319), peak power (r = -.041, P = .894), net impulse (r = -.028, P = .927), and RFD (r = -.434, P = .138) were not statistically significant. Ballistic COHS may enhance SJ performance; however, the changes in performance were not related to bilateral symmetry.

Material removal rate fiber optic corrosion sensor

NASA Astrophysics Data System (ADS)

Trego, Angela; Haugse, Eric D.; Udd, Eric

1998-09-01

Fiber Bragg grating sensors generally consist of a single grating written in a low-birefringent optical fiber. The wavelength shift of the peak in the reflected spectrum from these sensors can be used to measure a single component of strain or a change in temperature [Lawrence, 1997]. Fibers are also available with a significant enough birefringence to maintain the polarization state along great lengths and through many turns. This 'polarization maintaining' fiber is commercially available through several companies and in several configurations (including different cladding material and wavelength shift). The grating usually extends approximately 3 mm - 5 m in length. Udd gives a detailed explanation of fiber optics, Bragg gratings and birefringence [Udd, 1991]. As light from an LED is passed through the fiber, only the wavelength consistent with the grating period will be reflected back towards the source. All other wavelengths will pass through. The reflected spectrum will shift as the fiber is strained along its axis at the grating location. Strain or temperature changes at any other location have negligible effect on the wavelength encoded data output. When the Fiber Bragg grating single-axis sensor (termed fiber hereafter) is strained transversely the wavelength will separate into two distinct peaks according to a mathematical relationship defined by Lawrence and Nelson [Lawrence, Nelson et al. 96]. Using these Fiber Bragg grating fibers a corrosion sensor which measures the rate of material was developed. The principle behind this newly developed corrosion sensor is to pre-stress the fiber with a known load. The load is applied by inducing a uniform hoop stress through pressure fitted cylinders around the fiber. This induced stress creates a broadening of the reflected spectrum until the bifurcation of the reflected intensity peaks is distinguishable. As the material from the outer cylinder corrodes away the applied stress will be relieved. Finally, when no load is achieved, the reflected spectrum will have a single peak centered around the nominal Bragg grating wavelength. If a polarizing-maintaining 3-axis grating is used then the sensor would be even more sensitive, having two distinct peaks in each wavelength regime which shift.

Diamond structure recovery during ion irradiation at elevated temperatures

NASA Astrophysics Data System (ADS)

Deslandes, Alec; Guenette, Mathew C.; Belay, Kidane; Elliman, Robert G.; Karatchevtseva, Inna; Thomsen, Lars; Riley, Daniel P.; Lumpkin, Gregory R.

2015-12-01

CVD diamond is irradiated by 5 MeV carbon ions, with each sample held at a different temperature (300-873 K) during irradiations. The defect structures resulting from the irradiations are evident as vacancy, interstitial and amorphous carbon signals in Raman spectra. The observed variation of the full width at half maximum (FWHM) and peak position of the diamond peak suggests that disorder in the diamond lattice is reduced for high temperature irradiations. The dumbbell interstitial signal is reduced for irradiations at 873 K, which suggests this defect is unstable at these temperatures and that interstitials have migrated to crystal surfaces. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy results indicate that damage to the diamond structure at the surface has occurred for room temperature irradiations, however, this structure is at least partially recovered for irradiations performed at 473 K and above. The results suggest that, in a high temperature irradiation environment such as a nuclear fusion device, in situ annealing of radiation-created defects can maintain the diamond structure and prolong the lifetime of diamond components.

500-m and 1000-m moderate walks equally assess cardiorespiratory fitness in male outpatients with cardiovascular diseases.

PubMed

Mazzoni, Gianni; Chiaranda, Giorgio; Myers, Jonathan; Sassone, Biagio; Pasanisi, Giovanni; Mandini, Simona; Volpato, Stefano; Conconi, Francesco; Grazzi, Giovanni

2017-09-29

The walking speed maintained during a moderate 1-km treadmill walk (1k-TWT) has been demonstrated to be a valid tool for estimating peak oxygen uptake (VO2peak), and to be inversely related to long-term survival and hospitalization in outpatients with cardiovascular disease (CVD). We aimed to examine whether 500-m and 1-k moderate treadmill-walking tests equally estimate VO2peak in male outpatients with CVD. 142 clinically stable male outpatients with CVD, aged 34-92 years, referred to an exercise-based secondary prevention program, performed a moderate and perceptually-regulated (11-13/20 on the Borg scale) 1k- TWT. Age, height, weight, time to walk 500-m and the entire 1000-m, and the corresponding heart rates were entered into validated equations to estimate VO2peak. VO2peak estimated from the 500-m test was not different from that estimated from the 1k test (25.2±5.1 vs 25.1±5.2 mL/kg/min). The correlation coefficient between the two was 0.98. The slope and the intercept of the relationship between the 500-m and 1k tests were not different from the line of identity. Bland-Altman analysis demonstrated that 96% of the data points were within two standard deviations (from -1.9 to 1.7 mL/kg/min). The 500-m treadmill-walking test is a reliable method for estimating VO2peak in stable male outpatients with CVD. A shorter version of the test, 500-m, provides similar information as that from the original 1k test, but is more time efficient. These findings have practical implications in the context of transitioning patients from clinically based and supervised programs to fitness facilities or self-guided exercise programs.

Model Development and Experimental Validation of the Fusible Heat Sink Design for Exploration Vehicles

NASA Technical Reports Server (NTRS)

Cognata, Thomas J.; Leimkuehler, Thomas O.; Sheth, Rubik B.; Le,Hung

2012-01-01

The Fusible Heat Sink is a novel vehicle heat rejection technology which combines a flow through radiator with a phase change material. The combined technologies create a multi-function device able to shield crew members against Solar Particle Events (SPE), reduce radiator extent by permitting sizing to the average vehicle heat load rather than to the peak vehicle heat load, and to substantially absorb heat load excursions from the average while constantly maintaining thermal control system setpoints. This multi-function technology provides great flexibility for mission planning, making it possible to operate a vehicle in hot or cold environments and under high or low heat load conditions for extended periods of time. This paper describes the model development and experimental validation of the Fusible Heat Sink technology. The model developed was intended to meet the radiation and heat rejection requirements of a nominal MMSEV mission. Development parameters and results, including sizing and model performance will be discussed. From this flight-sized model, a scaled test-article design was modeled, designed, and fabricated for experimental validation of the technology at Johnson Space Center thermal vacuum chamber facilities. Testing showed performance comparable to the model at nominal loads and the capability to maintain heat loads substantially greater than nominal for extended periods of time.

Model Development and Experimental Validation of the Fusible Heat Sink Design for Exploration Vehicles

NASA Technical Reports Server (NTRS)

Cognata, Thomas J.; Leimkuehler, Thomas; Sheth, Rubik; Le, Hung

2013-01-01

The Fusible Heat Sink is a novel vehicle heat rejection technology which combines a flow through radiator with a phase change material. The combined technologies create a multi-function device able to shield crew members against Solar Particle Events (SPE), reduce radiator extent by permitting sizing to the average vehicle heat load rather than to the peak vehicle heat load, and to substantially absorb heat load excursions from the average while constantly maintaining thermal control system setpoints. This multi-function technology provides great flexibility for mission planning, making it possible to operate a vehicle in hot or cold environments and under high or low heat load conditions for extended periods of time. This paper describes the modeling and experimental validation of the Fusible Heat Sink technology. The model developed was intended to meet the radiation and heat rejection requirements of a nominal MMSEV mission. Development parameters and results, including sizing and model performance will be discussed. From this flight-sized model, a scaled test-article design was modeled, designed, and fabricated for experimental validation of the technology at Johnson Space Center thermal vacuum chamber facilities. Testing showed performance comparable to the model at nominal loads and the capability to maintain heat loads substantially greater than nominal for extended periods of time.

Strength training improves the tri-digit finger-pinch force control of older adults.

PubMed

Keogh, Justin W; Morrison, Steve; Barrett, Rod

2007-08-01

To investigate the effect of unilateral upper-limb strength training on the finger-pinch force control of older men. Pretest and post-test 6-week intervention study. Exercise science research laboratory. Eleven neurologically fit older men (age range, 70-80y). The strength training group (n=7) trained twice a week for 6 weeks, performing dumbbell bicep curls, wrist flexions, and wrists extensions, while the control group subjects (n=4) maintained their normal activities. Changes in force variability, targeting error, peak power frequency, proportional power, sample entropy, digit force sharing, and coupling relations were assessed during a series of finger-pinch tasks. These tasks involved maintaining a constant or sinusoidal force output at 20% and 40% of each subject's maximum voluntary contraction. All participants performed the finger-pinch tasks with both the preferred and nonpreferred limbs. Analysis of covariance for between-group change scores indicated that the strength training group (trained limb) experienced significantly greater reductions in finger-pinch force variability and targeting error, as well as significantly greater increases in finger-pinch force, sample entropy, bicep curl, and wrist flexion strength than did the control group. A nonspecific upper-limb strength-training program may improve the finger-pinch force control of older men.

Effects of Moth Age and Rearing Temperature on the Flight Performance of the Loreyi Leafworm, Mythimna loreyi (Lepidoptera: Noctuidae), in Tethered and Free Flight.

PubMed

Qin, Jianyang; Liu, Yueqiu; Zhang, Lei; Cheng, Yunxia; Sappington, Thomas W; Jiang, Xingfu

2018-05-28

To understand the migratory flight behaviors of the loreyi leafworm, Mythimna loreyi Walker (Lepidoptera: Noctuidae), both tethered (flight distance, time, and velocity) and free-flight activity (flight action, duration, and frequency) of adults at different ages, sexes, and temperatures were investigated using computer-controlled insect flight mills and an autonomous flight monitoring system. Tethered flight activity differed significantly among ages and rearing temperature, but not sex. Newly emerged adults (the first day after emergence) displayed the lowest flight time, distance, and speed. However, flight performance increased with age, peaking at 3 d. Relatively strong flight performance was maintained up to 5 d postemergence and then declined significantly by day 6. There was no significant difference in flight performance between sexes for 3-d-old moths. Adults reared as larvae at 24°C averaged significantly longer flight duration and distance than those reared at other temperatures. Both lower and higher rearing temperatures negatively affected tethered flight. Similar results among age and rearing temperature treatments were observed in autonomous free-flight tests. During 12-h free-flight tests, flight activity peaked from 6 to 10 h after beginning of darkness. Free-flight activity of 1- and 6-d-old adults was significantly less than that of 3-, 4-, and 5-d-old adults. Adults reared at 24°C showed significantly greater free-flight action, duration, and frequency than those reared at other temperatures. The results suggest that M. loreyi may be a migratory species.

WISE-2005: LBNP/Treadmill and Resistive Exercise Countermeasures Maintain Aerobic Capacity during a 60-d Bed Rest

NASA Technical Reports Server (NTRS)

Schneider, Suzanne M.; Lee, Stuart M. C.; Watenpaugh, Donald E.; Macias, Brandon R.; Hargens, Alan R.

2006-01-01

We have previously documented that supine treadmill exercise within lower body negative pressure (LBNPex) performed 6 sessions (raised dot) wk(sup -1) during 15- and 30-day bed rests (BR) maintained upright aerobic capacity (VO2pk). In the present study, ure are evaluating whether aerobic capacity is maintained during a 60-d BR when the LBNPex frequency is reduced to 2-4 sessions (raised dot) wk(sup -1) and resistance exercise (REX) is added 2-3 sessions (raised dot) wk(sup -1). Eight healthy women (32 plus or minus 4 yrs; 56.4 plus or minus 3.6 kg; 164 plus or minus 8 cm; mean plus or minus SD) performed maximal-exertion, graded treadmill tests before and 3 days after a 60-d, 6 deg. head-down tilt BR. (Earliest day the medical monitors would permit a maximal exercise test post-BR). During BR, four subjects performed no exercise (CON), while four other subjects (EX) performed LBNPex and REX on separate days. The LBNPex countermeasure employed an intermittent (40-80% pre-BR VO2pk), 40-min protocol against an LBNP pressure (-49 plus or minus 3 mmHg) applied to provide a footward force equivalent to 1.0-1.2 body weight. REX consisted of maximal concentric and eccentric supine leg press and heel raise exercises using a gravity-independent flywheel ergometer. Comparisons were performed using paired (within-group) or non-paired (between-group) t-tests. Three days post-BR, VO2pk of the CON group was reduced significantly from pre-BR (Pre:37.2 plus or minus 1.2, Post: 29.4 plus or minus 2 ml (raised dot) kg(sup -1) (raised dot) min(sup -1), P less than 0.05), while the VO2pk of the EX group was not significantly reduced (Pre: 39.6 plus or minus 1.9, Post: 38.0 plus or minus 0.6 ml (raised dot) kg(sup -1) (raised dot) min(sup -1)). Peak heart rate, ventilation, rating of perceived exertion, and respiratory exchange ratio were not significantly different between the two groups pre- and post-BR. These preliminary results suggest that the combined LBNPex and REX countermeasures may be sufficient to maintain upright aerobic capacity after long-duration space flights.

Acoustic performance of low pressure axial fan rotors with different blade chord length and radial load distribution

NASA Astrophysics Data System (ADS)

Carolus, Thomas

The paper examines the acoustic and aerodynamic performance of low-pressure axial fan rotors with a hub/tip ratio of 0.45. Six rotors were designed for the same working point by means of the well-known airfoil theory. The condition of an equilibrium between the static pressure gradient and the centrifugal forces is maintained. All rotors have unequally spaced blades to diminish tonal noise. The rotors are tested in a short cylindrical housing without guide vanes. All rotors show very similar flux-pressure difference characteristics. The peak efficiency and the noise performance is considerably influenced by the chosen blade design. The aerodynamically and acoustically optimal rotor is the one with the reduced load at the hub and increased load in the tip region under satisfied equilibrium conditions. It runs at the highest aerodynamic efficiency, and its noise spectrum is fairly smooth. The overall sound pressure level of this rotor is up to 8 dB (A) lower compared to the other rotors under consideration.

Aerocapture Guidance and Performance at Mars for High-Mass Systems

NASA Technical Reports Server (NTRS)

Zumwalt, Carlie H.; Sostaric, Ronald r.; Westhelle, Carlos H.; Cianciolo, Alicia Dwyer

2010-01-01

The objective of this study is to understand the performance associated with using the aerocapture maneuver to slow high-mass systems from an Earth-approach trajectory into orbit around Mars. This work is done in conjunction with the Mars Entry Descent and Landing Systems Analysis (EDL-SA) task to explore candidate technologies necessary for development in order to land large-scale payloads on the surface of Mars. Among the technologies considered include hypersonic inflatable aerodynamic decelerators (HIADs) and rigid mid-lift to drag (L/D) aeroshells. Nominal aerocapture trajectories were developed for the mid-L/D aeroshell and two sizes of HIADs, and Monte Carlo analysis was completed to understand sensitivities to dispersions. Additionally, a study was completed in order to determine the size of the larger of the two HIADs which would maintain design constraints on peak heat rate and diameter. Results show that each of the three aeroshell designs studied is a viable option for landing high-mass payloads as none of the three exceed performance requirements.

Dietary Supplements for Musculoskeletal Pain: Science Versus Claims.

PubMed

Crawford, Cindy; Saldanha, Leila; Costello, Rebecca; Deuster, Patricia A

2018-01-01

Special Operations Forces (SOF) face unique challenges that manifest themselves both mentally and physically. The extremes of training and combat can affect the readiness to perform at peak levels, especially when confronted with musculoskeletal pain. Many SOF Operators turn to dietary supplements in hopes of gaining an edge. Although some supplements are now being marketed for pain, decisions to use these products need to be driven by information that is evidence based. We describe SOF-specific evidence-based recommendations for the use of dietary ingredients for pain that emerged from a rigorous scientific evaluation. These recommendations are compared with the label claims made in the commercial market by companies selling products to combat musculoskeletal pain. This information can be used by the SOF medical community to assist Operators in making informed decisions when considering or selecting dietary supplements for maintaining and optimizing performance. 2018.

VizieR Online Data Catalog: Swift and NuSTAR obs. of the BL Lac Mrk 421 (Kapanadze+, 2016)

NASA Astrophysics Data System (ADS)

Kapanadze, B.; Dorner, D.; Vercellone, S.; Romano, P.; Aller, H.; Aller, M.; Hughes, P.; Reynolds, M.; Kapanadze, S.; Tabagari, L.

2017-01-01

We retrieved the Swift-XRT data from the publicly available archive, maintained by HEASARC. We present the results of X-ray observations of the high-energy peaked BL Lac (HBL) source Mrk421 performed by Swift-XRT and NuSTAR during 2013 January-June. Along with the 0.3-10keV and 3-79keV data obtained with the Swift-XRT and NuSTAR instruments, we have processed and analyzed those obtained with the Ultraviolet-Optical Telescope (UVOT) and Large Area Telescope (LAT) onboard Fermi. We have also used the publicly available light curves from the observations performed with the Burst Alert Telescope (BAT) onboard Swift, Monitor of All Sky X-ray Image (MAXI), MAGIC, First G-APD Cherenkov Telescope (FACT), and the OVRO 40m telescope during the 2013 January-June period to draw conclusions about the interband correlations. (8 data files).

Acute physiological responses to recreational in-line skating in young adults.

PubMed

Orepic, Paula; Mikulic, Pavle; Soric, Maroje; Ruzic, Lana; Markovic, Goran

2014-01-01

We examined the physiological responses to in-line skating exercise at self-selected paces in recreationally trained adults. Seven men and 10 women performed in-line skating exercise during which oxygen uptake (VO2) and heart rate (HR) were recorded continuously. Ratings of perceived exertion (RPE) and blood lactate concentration were also obtained at the end of exercise. Furthermore, subjects' peak VO2, peak HR, RPE and gas-exchange thresholds were determined in laboratory settings. The average exercise intensity during in-line skating was 90% of peak HR, 67% of peak VO2, 84% of HR reserve and 64% of VO2 reserve. When expressed as RPE and as metabolic equivalents (METs), the average exercise intensity was 13.1 RPE and 9.4 METs. Overall, these indicators of exercise intensity categorise in-line skating at self-selected paces as a vigorous physical activity. Notably, at similar VO2 values, significantly higher HR (174 ± 16 vs. 156 ± 6 bpm; p<0.001) and RPE (13.1 ± 1.4 vs. 11.7 ± 1.4; p=0.019) were observed for in-line skating compared with treadmill running. We conclude that 1. recreational in-line skating induces physiological responses that are sufficient for improving and maintaining cardiovascular fitness in healthy adults, 2. HR- and RPE-based methods for quantifying the exercise intensity during in-line skating may overestimate the actual metabolic load and 3. the derivation of exercise prescriptions for in-line skating should be preferably based on specific (i.e. in-line skating) graded exhaustive exercise test.

The Effect of Increasing Mass upon Locomotion

NASA Technical Reports Server (NTRS)

DeWitt, John; Hagan, Donald

2007-01-01

The purpose of this investigation was to determine if increasing body mass while maintaining bodyweight would affect ground reaction forces and joint kinetics during walking and running. It was hypothesized that performing gait with increased mass while maintaining body weight would result in greater ground reaction forces, and would affect the net joint torques and work at the ankle, knee and hip when compared to gait with normal mass and bodyweight. Vertical ground reaction force was measured for ten subjects (5M/5F) during walking (1.34 m/s) and running (3.13 m/s) on a treadmill. Subjects completed one minute of locomotion at normal mass and bodyweight and at four added mass (AM) conditions (10%, 20%, 30% and 40% of body mass) in random order. Three-dimensional joint position data were collected via videography. Walking and running were analyzed separately. The addition of mass resulted in several effects. Peak impact forces and loading rates increased during walking, but decreased during running. Peak propulsive forces decreased during walking and did not change during running. Stride time increased and hip extensor angular impulse and positive work increased as mass was added for both styles of locomotion. Work increased at a greater rate during running than walking. The adaptations to additional mass that occur during walking are different than during running. Increasing mass during exercise in microgravity may be beneficial to increasing ground reaction forces during walking and strengthening hip musculature during both walking and running. Future study in true microgravity is required to determine if the adaptations found would be similar in a weightless environment.

PeakRanger: A cloud-enabled peak caller for ChIP-seq data

PubMed Central

2011-01-01

Background Chromatin immunoprecipitation (ChIP), coupled with massively parallel short-read sequencing (seq) is used to probe chromatin dynamics. Although there are many algorithms to call peaks from ChIP-seq datasets, most are tuned either to handle punctate sites, such as transcriptional factor binding sites, or broad regions, such as histone modification marks; few can do both. Other algorithms are limited in their configurability, performance on large data sets, and ability to distinguish closely-spaced peaks. Results In this paper, we introduce PeakRanger, a peak caller software package that works equally well on punctate and broad sites, can resolve closely-spaced peaks, has excellent performance, and is easily customized. In addition, PeakRanger can be run in a parallel cloud computing environment to obtain extremely high performance on very large data sets. We present a series of benchmarks to evaluate PeakRanger against 10 other peak callers, and demonstrate the performance of PeakRanger on both real and synthetic data sets. We also present real world usages of PeakRanger, including peak-calling in the modENCODE project. Conclusions Compared to other peak callers tested, PeakRanger offers improved resolution in distinguishing extremely closely-spaced peaks. PeakRanger has above-average spatial accuracy in terms of identifying the precise location of binding events. PeakRanger also has excellent sensitivity and specificity in all benchmarks evaluated. In addition, PeakRanger offers significant improvements in run time when running on a single processor system, and very marked improvements when allowed to take advantage of the MapReduce parallel environment offered by a cloud computing resource. PeakRanger can be downloaded at the official site of modENCODE project: http://www.modencode.org/software/ranger/ PMID:21554709

Muscarinic receptor binding increases in anterior thalamus and cingulate cortex during discriminative avoidance learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vogt, B.A.; Gabriel, M.; Vogt, L.J.

Training-induced neuronal activity develops in the mammalian limbic system during discriminative avoidance conditioning. This study explores behaviorally relevant changes in muscarinic ACh receptor binding in 52 rabbits that were trained to one of five stages of conditioned response acquisition. Sixteen naive and 10 animals yoked to criterion performance served as control cases. Upon reaching a particular stage of training, the brains were removed and autoradiographically assayed for 3H-oxotremorine-M binding with 50 nM pirenzepine (OxO-M/PZ) or for 3H-pirenzepine binding in nine limbic thalamic nuclei and cingulate cortex. Specific OxO-M/PZ binding increased in the parvocellular division of the anterodorsal nucleus early inmore » training when the animals were first exposed to pairing of the conditional and unconditional stimuli. Elevated binding in this nucleus was maintained throughout subsequent training. In the parvocellular division of the anteroventral nucleus (AVp), OxO-M/PZ binding progressively increased throughout training, reached a peak at the criterion stage of performance, and returned to control values during extinction sessions. Peak OxO-M/PZ binding in AVp was significantly elevated over that for cases yoked to criterion performance. In the magnocellular division of the anteroventral nucleus (AVm), OxO-M/PZ binding was elevated only during criterion performance of the task, and it was unaltered in any other limbic thalamic nuclei. Specific OxO-M/PZ binding was also elevated in most layers in rostral area 29c when subjects first performed a significant behavioral discrimination. Training-induced alterations in OxO-M/PZ binding in AVp and layer Ia of area 29c were similar and highly correlated.« less

Sex-related differences and age of peak performance in breaststroke versus freestyle swimming

PubMed Central

2013-01-01

Background Sex-related differences in performance and in age of peak performance have been reported for freestyle swimming. However, little is known about the sex-related differences in other swimming styles. The aim of the present study was to compare performance and age of peak performance for elite men and women swimmers in breaststroke versus freestyle. Methods Race results were analyzed for swimmers at national ranked in the Swiss high score list (during 2006 through 2010) and for international swimmers who qualified for the finals of the FINA World Swimming Championships (during 2003 through 2011). Results The sex-related difference in swimming speed was significantly greater for freestyle than for breaststroke over 50 m, 100 m, and 200 m race distances for Swiss swimmers, but not for FINA finalists. The sex-related difference for both freestyle and breaststroke swimming speeds decreased significantly with increasing swimming distance for both groups. Race distance did not affect the age of peak performance by women in breaststroke, but age of peak performance was four years older for FINA women than for Swiss women. Men achieved peak swimming performance in breaststroke at younger ages for longer race distances, and the age of peak swimming performance was six years older for FINA men than for Swiss men. In freestyle swimming, race distance did not affect the age of peak swimming performance for Swiss women, but the age of peak swimming performance decreased with increasing race distance for Swiss men and for both sexes at the FINA World Championships. Conclusions Results of the present study indicate that (i) sex-related differences in swimming speed were greater for freestyle than for breaststroke for swimmers at national level, but not for swimmers at international level, and (ii) both female and male swimmers achieved peak swimming speeds at younger ages in breaststroke than in freestyle. Further studies are required to better understand differences between trends at national and international levels. PMID:24351335

Effects of Aerobic Exercise Based upon Heart Rate at Aerobic Threshold in Obese Elderly Subjects with Type 2 Diabetes

PubMed Central

Donini, Lorenzo Maria

2015-01-01

In obese diabetic subjects, a correct life style, including diet and physical activity, is part of a correct intervention protocol. Thus, the aim of this study was to evaluate the effects of aerobic training intervention, based on heart rate at aerobic gas exchange threshold (AerTge), on clinical and physiological parameters in obese elderly subjects with type 2 diabetes (OT2DM). Thirty OT2DM subjects were randomly assigned to an intervention (IG) or control group (CG). The IG performed a supervised aerobic exercise training based on heart rate at AerTge whereas CG maintained their usual lifestyle. Anthropometric measures, blood analysis, peak oxygen consumption (V˙O2peak), metabolic equivalent (METpeak), work rate (WRpeak), and WRAerTge were assessed at baseline and after intervention. After training, patients enrolled in the IG had significantly higher (P < 0.001) V˙O2peak, METpeak, WRpeak, and WRAerTge and significantly lower (P < 0.005) weight, BMI, %FM, and waist circumference than before intervention. Both IG and CG subjects had lower glycated haemoglobin levels after intervention period. No significant differences were found for all the other parameters between pre- and posttraining and between groups. Aerobic exercise prescription based upon HR at AerTge could be a valuable physical intervention tool to improve the fitness level and metabolic equilibrium in OT2DM patients. PMID:26089890

The Effect of Driver Rise-Time on Pinch Current and its Impact on Plasma Focus Performance and Neutron Yield

NASA Astrophysics Data System (ADS)

Sears, Jason; Schmidt, Andrea; Link, Anthony; Welch, Dale

2016-10-01

Experiments have suggested that dense plasma focus (DPF) neutron yield increases with faster drivers [Decker NIMP 1986]. Using the particle-in-cell code LSP [Schmidt PRL 2012], we reproduce this trend in a kJ DPF [Ellsworth 2014], and demonstrate how driver rise time is coupled to neutron output. We implement a 2-D model of the plasma focus including self-consistent circuit-driven boundary conditions. Driver capacitance and voltage are varied to modify the current rise time, and anode length is adjusted so that run-in coincides with the peak current. We observe during run down that magnetohydrodynamic (MHD) instabilities of the sheath shed blobs of plasma that remain in the inter-electrode gap during run in. This trailing plasma later acts as a low-inductance restrike path that shunts current from the pinch during maximum compression. While the MHD growth rate increases slightly with driver speed, the shorter anode of the fast driver allows fewer e-foldings and hence reduces the trailing mass between electrodes. As a result, the fast driver postpones parasitic restrikes and maintains peak current through the pinch during maximum compression. The fast driver pinch therefore achieves best simultaneity between its ion beam and peak target density, which maximizes neutron production. Prepared by LLNL under Contract DE-AC52-07NA27344.

Observation of the Intrinsic Bandgap Behavior in As-Grown Epitaxial Twisted Graphene (Postprint)

DTIC Science & Technology

2015-01-06

the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this...intensity, which becomes compar able to that of G band intensity and is now a symmetric , single Lorentzian peak. The third difference is the 2D band peak...spectrum with SiC signal subtracted. (c,d) Variation of Raman C60/GF FLG spectra as a function of C60 deposition time . A single Lorentzian 2D band was

Annual peak discharges from small drainage areas in Montana for stations discontinued before 1978

USGS Publications Warehouse

Omang, R.J.; Hull, J.A.; Parrett, Charles

1979-01-01

Annual peak stage and discharge data have been tabulated for crest-stage gage sites in Montana. The crest-stage program was begun in July 1955 to investigate the magnitude and frequency of floods from samll drainage areas. The program has expanded from 45 crest-stage gaging stations initially to 172 stations maintained in 1978. From 1955 to 1978, 156 stations have been discontinued. This report is a tabulation of the stage and discharge data for the discontinued stations. (Woodard-USGS)

The influence of hip abductor muscle performance on dynamic postural stability in females with patellofemoral pain.

PubMed

Lee, Szu-Ping; Souza, Richard B; Powers, Christopher M

2012-07-01

Hip abductors play an important role in maintaining trunk and pelvis stability during unipedal tasks. The purpose of the study was to compare postural stability between individuals with patellofemoral pain (PFP) and pain-free controls. A secondary purpose was to evaluate the effect of a hip stabilizing brace on postural stability. Twenty females with PFP (27.3±6.3 years) and 19 controls (26.1±4.5 years) participated. Each subject performed a unipedal step-down balance task with the stance leg on a force platform from which center of pressure (COP) excursion was recorded. Quantitative COP excursion patterns (mean and peak displacements) were used as measures of postural stability. For subjects with PFP, postural stability also was quantified following the application of a hip stabilizing brace. Hip abductor strength was significantly lower in PFP group compared to the control group (1.39±0.4 vs. 1.62±0.26 N/kg-BW, p=0.046). Peak and mean medial-lateral COP displacements during the balance task were greater in the PFP group (39.8±6.7 vs. 24.3±3.8 mm, p<0.001; 24.7±16.3 vs. 13.5±4.4 mm, p=0.005). Application of the hip stabilizing brace reduced the peak and mean COP displacement (39.8±6.7 vs. 24.7±4.7 mm, p<0.001; 24.7±16.3 vs. 16.8±15.1 mm, p=0.02). Our results demonstrate that females with PFP exhibit impaired medial-lateral postural stability when compared to control subjects. Application of a hip stabilizing brace significantly improved stability to a level comparable to the controls. Copyright © 2012 Elsevier B.V. All rights reserved.

Sleep deprivation affects sensorimotor coupling in postural control of young adults.

PubMed

Aguiar, Stefane A; Barela, José A

2014-06-27

Although impairments in postural control have been reported due to sleep deprivation, the mechanisms underlying such performance decrements still need to be uncovered. The purpose of this study was to investigate the effects of sleep deprivation on the relationship between visual information and body sway in young adults' postural control. Thirty adults who remained awake during one night and 30 adults who slept normally the night before the experiment participated in this study. The moving room paradigm was utilized, manipulating visual information through the movement of a room while the floor remained motionless. Subjects stood upright inside of a moving room during four 60-s trials. In the first trial the room was kept stationary and in the following trials the room moved with a frequency of 0.2Hz, peak velocity of 0.6cm/s and 0.9cm peak-to-peak amplitude. Body sway and room displacement were measured through infrared markers. Results showed larger and faster body sway in sleep deprived subjects with and without visual manipulation. The magnitude with which visual stimulus influenced body sway and its temporal relationship were unaltered in sleep deprived individuals, but they became less coherent and more variable as they had to maintain upright stance during trials. These results indicate that after sleep deprivation adults become less stable and accurate in relating visual information to motor action, and this effect is observed after only a brief period performing postural tasks. The low cognitive load employed in this task suggests that attentional difficulties are not the only factor leading to sensorimotor coupling impairments observed following sleep deprivation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Generation and preservation of the slow underlying membrane potential oscillation in model bursting neurons.

PubMed

Franklin, Clarence C; Ball, John M; Schulz, David J; Nair, Satish S

2010-09-01

The underlying membrane potential oscillation of both forced and endogenous slow-wave bursting cells affects the number of spikes per burst, which in turn affects outputs downstream. We use a biophysical model of a class of slow-wave bursting cells with six active currents to investigate and generalize correlations among maximal current conductances that might generate and preserve its underlying oscillation. We propose three phases for the underlying oscillation for this class of cells: generation, maintenance, and termination and suggest that different current modules coregulate to preserve the characteristics of each phase. Coregulation of I(Burst) and I(A) currents within distinct boundaries maintains the dynamics during the generation phase. Similarly, coregulation of I(CaT) and I(Kd) maintains the peak and duration of the underlying oscillation, whereas the calcium-activated I(KCa) ensures appropriate termination of the oscillation and adjusts the duration independent of peak.

Maintenance of in vivo induced cytochrome P-450s in hepatocyte monolayers at non freezing temperatures.

PubMed

Evans, Peter J

2015-04-01

Cytochrome P450s (CYPs) induced in rats by 3-methylcholanthrene (3-MC), phenobarbital (PB) and dexamethasone (Dex) were investigated. The inducers had no effect on hepatocyte yield, viability, attachment or spreading on collagen. 3-MC induced ethoxyresorufin deethylase (EROD). Under normothermic conditions the activity fell in culture. However, it was maintained when cells were preserved at 10°C under a gelatin gel. Upon reactivation the activity mirrored that of freshly isolated cells at 37°C. Induced levels were stable for at least 6h , the time to form a confluent monolayer. The investigation was extended to other CYPs by looking at patterns of testosterone metabolism. Phenobarbital had the greatest influence in terms of the quantity and number of metabolites. Culture at 37°C decreased the peaks dramatically within 24 h. All 7 peaks were maintained in the preservation system. Copyright © 2015 Elsevier Inc. All rights reserved.

An in vitro evaluation of the influence of neonatal endotracheal tube diameter and length on the work of breathing.

PubMed

Miyake, Fuyu; Suga, Rika; Akiyama, Takahiro; Namba, Fumihiko

2018-04-06

Neonates, particularly premature babies, are often managed with endotracheal intubation and subsequent mechanical ventilation to maintain adequate pulmonary gas exchange. There is no consensus on the standard length of endotracheal tube. Although a short tube reduces resistance and respiratory dead space, it is believed to increase the risk of accidental extubation. There are not entirely coherent data regarding the effect of endotracheal tube length on work of breathing in infants. The aim of this study was to evaluate the impact of neonatal endotracheal tube diameter and length on the work of breathing using an infant in vitro lung model. We assessed the work of breathing index and mechanical ventilation settings with various endotracheal tube diameters and lengths using the JTR100 in vitro infant lung model. The basic parameters of the model were breathing frequency of 20 per minutes, inspiratory-expiratory ratio of 1:3, and positive end-expiratory pressure of 5 cmH 2 O. In addition, the diaphragm driving pressure to maintain the set tidal volume was measured as the work of breathing index. The JTR100 was connected to the Babylog 8000plus through the endotracheal tube. Finally, we monitored the peak inspiratory pressure generated during assist-control volume guarantee mode with a targeted tidal volume of 10-30 mL. The diaphragm driving pressure using a 2.0-mm inner diameter tube was twice as high as that using a 4.0-mm inner diameter tube. To maintain the targeted tidal volume, a shorter tube reduced both the diaphragm driving pressure and ventilator-generated peak inspiratory pressure. The difference in the generated peak inspiratory pressure between the shortest and longest tubes was 5 cmH 2 O. In our infant lung model, a shorter tube resulted in a lower work of breathing and lower ventilator-generated peak inspiratory pressure. © 2018 John Wiley & Sons Ltd.

Peak water limits to freshwater withdrawal and use

PubMed Central

Gleick, Peter H.; Palaniappan, Meena

2010-01-01

Freshwater resources are fundamental for maintaining human health, agricultural production, economic activity as well as critical ecosystem functions. As populations and economies grow, new constraints on water resources are appearing, raising questions about limits to water availability. Such resource questions are not new. The specter of “peak oil”—a peaking and then decline in oil production—has long been predicted and debated. We present here a detailed assessment and definition of three concepts of “peak water”: peak renewable water, peak nonrenewable water, and peak ecological water. These concepts can help hydrologists, water managers, policy makers, and the public understand and manage different water systems more effectively and sustainably. Peak renewable water applies where flow constraints limit total water availability over time. Peak nonrenewable water is observable in groundwater systems where production rates substantially exceed natural recharge rates and where overpumping or contamination leads to a peak of production followed by a decline, similar to more traditional peak-oil curves. Peak “ecological” water is defined as the point beyond which the total costs of ecological disruptions and damages exceed the total value provided by human use of that water. Despite uncertainties in quantifying many of these costs and benefits in consistent ways, more and more watersheds appear to have already passed the point of peak water. Applying these concepts can help shift the way freshwater resources are managed toward more productive, equitable, efficient, and sustainable use. PMID:20498082

NACA Wartime Safety Poster

NASA Image and Video Library

1945-04-21

One of many safety posters produced by NACA artists during World War II. The Aircraft Engine Research Laboratory established a Safety Office in 1942 to coordinate and oversee safety-related activities. The lab struggled to maintain a full staff during the war when military research projects were at a peak. NACA management mandated six-day work weeks without overtime and the elimination of holidays. As such, workplace injuries were a serious threat to maintaining productivity needed to sustain the military’s aeronautics efforts.

The different effects of high intensity interval training and moderate intensity interval training for weightlessness countermeasures

NASA Astrophysics Data System (ADS)

Wang, Lin-Jie; Cheng, Tan; Zhi-Li, Li; Hui-juan, Wang; Wen-juan, Chen; Jianfeng, Zhang; Desheng, Wang; Dongbin, Niu; Qi, Zhao; Chengjia, Yang; Yanqing, Wang

High intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. But the difference between high intensity interval training and moderate intensity interval training (MIIT) in simulated weightlessness still has not been well studied. This study sought to characterize the difference between 6 weeks high intensity interval training and moderate intensity interval training under reduced weight (RW) gait training device and zero-gravity locomotion system (ZLS). Twenty-three subjects (14M/4F, 32.5±4.5 years) volunteered to participate. They were divided into three groups, that were MITT (alternating 2 min at 40% VO _{2} peak and 2 min at 60% VO _{2} peak for 30min, five days per week) RW group (n=8), HITT (alternating 2 min at 40% VO _{2} peak and 2 min at 90% VO _{2} peak for 30min, three days per week) RW group (n=8) and HITT ZLS group (n=7). The Z-axis load used in RW group was 80% body weight (BW) and in ZLS was 100% BW. Cardiopulmonary function was measured before, after 4-week training and after 6-week training. Isokinetic knee extension-flexion test at 60(°) deg/s and 180(°) deg/s were performed before and after the 6-week training, and isometric knee extension-flexion test at 180(°) deg/s was also examined at the same time. It was found that the VO _{2} peaks, metabolic equivalent (MET), Speedmax and respiratory exchange ratio (RER) were significantly increased after 4 and 6-week training in all three groups and no significant group difference were detected. The peak torque at 60(°) deg/s for right knee flexion were significantly increased after 6 week-training in all three groups, and only in HITT RW group the total power at 60(°) deg/s for right knee flexion enhanced. The total power and average power at 60(°) deg/s for right knee extension decreased significantly after 6-week training in all three groups. The peak torque at 60(°) deg/s for right knee extension in MIIT RW group was significantly higher than that in HIIT ZLS group. The maximum average peak torque for isometric left knee contraction was enhanced after 6-week training in all three groups. It was suggested that HITT can be used in weightlessness to maintain the cardiopulmonary function in a relatively short training period, but the effect of HIIT on the maintenance of muscle function still need further study. (Supported by State Key Laboratory Grant NO. SMFA10A04 and The Twelfth Five Year Plan of Medical and Health Research Grant NO. BWS11J055)

Control over high peak-power laser light and laser-driven X-rays

NASA Astrophysics Data System (ADS)

Zhao, Baozhen; Banerjee, Sudeep; Yan, Wenchao; Zhang, Ping; Zhang, Jun; Golovin, Grigory; Liu, Cheng; Fruhling, Colton; Haden, Daniel; Chen, Shouyuan; Umstadter, Donald

2018-04-01

An optical system was demonstrated that enables continuous control over the peak power level of ultrashort duration laser light. The optical characteristics of amplified and compressed femtosecond-duration light from a chirped-pulse amplification laser are shown to remain invariant and maintain high-fidelity using this system. When the peak power was varied by an order-of-magnitude, up to its maximum attainable value, the phase, spectral bandwidth, polarization state, and focusability of the light remained constant. This capability led to precise control of the focused laser intensity and enabled a correspondingly high level of control over the power of an all-laser-driven Thomson X-ray light source.

Causal Scale of Rotors in a Cardiac System

NASA Astrophysics Data System (ADS)

Ashikaga, Hiroshi; Prieto-Castrillo, Francisco; Kawakatsu, Mari; Dehghani, Nima

2018-04-01

Rotors of spiral waves are thought to be one of the potential mechanisms that maintain atrial fibrillation (AF). However, disappointing clinical outcomes of rotor mapping and ablation to eliminate AF raise a serious doubt on rotors as a macro-scale mechanism that causes the micro-scale behavior of individual cardiomyocytes to maintain spiral waves. In this study, we aimed to elucidate the causal relationship between rotors and spiral waves in a numerical model of cardiac excitation. To accomplish the aim, we described the system in a series of spatiotemporal scales by generating a renormalization group, and evaluated the causal architecture of the system by quantifying causal emergence. Causal emergence is an information-theoretic metric that quantifies emergence or reduction between micro- and macro-scale behaviors of a system by evaluating effective information at each scale. We found that the cardiac system with rotors has a spatiotemporal scale at which effective information peaks. A positive correlation between the number of rotors and causal emergence was observed only up to the scale of peak causation. We conclude that rotors are not the universal mechanism to maintain spiral waves at all spatiotemporal scales. This finding may account for the conflicting benefit of rotor ablation in clinical studies.

Evaluation of different time domain peak models using extreme learning machine-based peak detection for EEG signal.

PubMed

Adam, Asrul; Ibrahim, Zuwairie; Mokhtar, Norrima; Shapiai, Mohd Ibrahim; Cumming, Paul; Mubin, Marizan

2016-01-01

Various peak models have been introduced to detect and analyze peaks in the time domain analysis of electroencephalogram (EEG) signals. In general, peak model in the time domain analysis consists of a set of signal parameters, such as amplitude, width, and slope. Models including those proposed by Dumpala, Acir, Liu, and Dingle are routinely used to detect peaks in EEG signals acquired in clinical studies of epilepsy or eye blink. The optimal peak model is the most reliable peak detection performance in a particular application. A fair measure of performance of different models requires a common and unbiased platform. In this study, we evaluate the performance of the four different peak models using the extreme learning machine (ELM)-based peak detection algorithm. We found that the Dingle model gave the best performance, with 72 % accuracy in the analysis of real EEG data. Statistical analysis conferred that the Dingle model afforded significantly better mean testing accuracy than did the Acir and Liu models, which were in the range 37-52 %. Meanwhile, the Dingle model has no significant difference compared to Dumpala model.

Modulations of Foot and Ankle Frontal Kinematics for Breaking and Propulsive Movement Characteristics during Side-Step Cutting with Varying Midsole Thicknesses

PubMed Central

Lin, Yi-Jia; Lee, Shih-Chi; Chang, Chao-Chin; Liu, Tsung-Han

2018-01-01

This study is aimed at determining the effects of midsole thickness on movement characteristic during side cutting movement. Fifteen athletes performed side-step cutting while wearing shoes with varying midsole thicknesses. Temporal-spatial and ground reaction force variables as well as foot and ankle frontal kinematics were used to describe breaking and propulsive movement characteristics and modulation strategies. Regardless of midsole thickness, temporal-spatial variables and breaking and propulsive force during side cutting were statistically unchanged. Significantly greater peaks of ankle inversion and plantarflexion with a thicker sole and greater midtarsal pronation with a thinner sole were observed. Current results demonstrated that hypotheses formed solely based on material testing were insufficient to understand the adaptations in human movement because of the redundancy of the neuromusculoskeletal system. Participants were able to maintain temporal-spatial performance during side cutting while wearing shoes with midsoles of varying thicknesses. Increased pronation for a thinner sole might help reduce the force of impact but might be associated with an increased risk of excessive stress on soft tissue. Increased peak of ankle inversion and plantarflexion for a thicker sole may be unfavorable for the stability of ankle joint. Information provided in human movement testing is crucial for understanding factors associated with movement characteristics and injury and should be considered in the future development of shoe design. PMID:29854000

High thermal tolerance of a rainbow trout population near its southern range limit suggests local thermal adjustment

PubMed Central

Verhille, Christine E.; English, Karl K.; Cocherell, Dennis E.; Farrell, Anthony P.; Fangue, Nann A.

2016-01-01

Transformation of earth's ecosystems by anthropogenic climate change is predicted for the 21st century. In many regions, the associated increase in environmental temperatures and reduced precipitation will have direct effects on the physiological performance of terrestrial and aquatic ectotherms and have already threatened fish biodiversity and important fisheries. The threat of elevated environmental temperatures is particularly salient for members of the Oncorhynchus genus living in California, which is the southern limit of their range. Here, we report the first assessments of the aerobic capacity of a Californian population of wild Oncorhynchus mykiss Walbaum in relationship to water temperature. Our field measurements revealed that wild O. mykiss from the lower Tuolumne River, California maintained 95% of their peak aerobic scope across an impressive temperature range (17.8–24.6°C). The thermal range for peak performance corresponds to local high river temperatures, but represents an unusually high temperature tolerance compared with conspecifics and congeneric species from northern latitudes. This high thermal tolerance suggests that O. mykiss at the southern limit of their indigenous distribution may be locally adjusted relative to more northern populations. From fisheries management and conservation perspectives, these findings challenge the use of a single thermal criterion to regulate the habitat of the O. mykiss species along the entirety of its distribution range. PMID:27957333

Career performance trajectories of Olympic swimmers: benchmarks for talent development.

PubMed

Allen, Sian V; Vandenbogaerde, Tom J; Hopkins, William G

2014-01-01

The age-related progression of elite athletes to their career-best performances can provide benchmarks for talent development. The purpose of this study was to model career performance trajectories of Olympic swimmers to develop these benchmarks. We searched the Web for annual best times of swimmers who were top 16 in pool events at the 2008 or 2012 Olympics, from each swimmer's earliest available competitive performance through to 2012. There were 6959 times in the 13 events for each sex, for 683 swimmers, with 10 ± 3 performances per swimmer (mean ± s). Progression to peak performance was tracked with individual quadratic trajectories derived using a mixed linear model that included adjustments for better performance in Olympic years and for the use of full-body polyurethane swimsuits in 2009. Analysis of residuals revealed appropriate fit of quadratic trends to the data. The trajectories provided estimates of age of peak performance and the duration of the age window of trivial improvement and decline around the peak. Men achieved peak performance later than women (24.2 ± 2.1 vs. 22.5 ± 2.4 years), while peak performance occurred at later ages for the shorter distances for both sexes (∼1.5-2.0 years between sprint and distance-event groups). Men and women had a similar duration in the peak-performance window (2.6 ± 1.5 years) and similar progressions to peak performance over four years (2.4 ± 1.2%) and eight years (9.5 ± 4.8%). These data provide performance targets for swimmers aiming to achieve elite-level performance.

MinXSS-1 CubeSat On-Orbit Pointing and Power Performance: The First Flight of the Blue Canyon Technologies XACT 3-axis Attitude Determination and Control System

NASA Astrophysics Data System (ADS)

Mason, James Paul; Baumgart, Matt; Rogler, Bryan; Downs, Chloe; Williams, Margaret; Woods, Thomas N.; Palo, Scott; Chamberlin, Phillip C.; Solomon, Stanley; Jones, Andrew; Li, Xinlin; Kohnert, Rick; Caspi, Amir

2017-12-01

The Miniature X-ray Solar Spectrometer (MinXSS) is a three-unit (3U) CubeSat designed for a three-month mission to study solar soft X-ray spectral irradiance. The first of the two flight models was deployed from the International Space Station in May 2016, and operated for one year before its natural deorbiting. This was the first flight of the Blue Canyon Technologies XACT 3-axis attitude determination and control system - a commercially available, high-precision pointing system. The performance of the pointing system on orbit was characterized, including performance at low altitudes where drag torque builds up. It was found that the pointing accuracy was 0.0042° - 0.0117° (15" - 42", 3σ, axis dependent) consistently from 190 km - 410 km, slightly better than the specification sheet states. Peak-to-peak jitter was estimated to be 0.0073° (10 s^-1) - 0.0183° (10 s^-1) (26" (10 s^-1) - 66" (10 s^-1), 3σ). The system was capable of dumping mome ntum until an altitude of 185 km. Small amounts of sensor degradation were found in the star tracker and coarse sun sensor. The mission profile did not require high-agility maneuvers, so it was not possible to characterize this metric. Without a GPS receiver, it was necessary to periodically upload ephemeris information to update the orbit propagation model and maintain pointing. At 400 km, these uploads were required once every other week; at ˜270 km, they were required every day. The power performance of the electric power system was also characterized, including use of a novel pseudo-peak power tracker - a resistor that limited the current draw from the battery on the solar panels. With 19 30% efficient solar cells and an 8 W system load, the power balance had 65% of margin on orbit. The current paper presents several recommendations to other CubeSat programs throughout.

Effects of four weeks of high-intensity interval training and creatine supplementation on critical power and anaerobic working capacity in college-aged men.

PubMed

Kendall, Kristina L; Smith, Abbie E; Graef, Jennifer L; Fukuda, David H; Moon, Jordan R; Beck, Travis W; Cramer, Joel T; Stout, Jeffrey R

2009-09-01

The critical power test provides 2 measures, critical power (CP) and anaerobic working capacity (AWC). In theory, the CP measurement represents the maximal power output that can be maintained without fatigue, and AWC is an estimate of work capacity associated with muscle energy reserves. High-intensity interval training (HIIT) has been shown to be an effective training method for improving endurance performance, including VO2PEAK. In addition, creatine (Cr) supplementation has been reported to improve AWC without training; however, it has shown no effect on CP. The purpose of this study was to examine the effects of 4 weeks of HIIT with Cr supplementation on CP and AWC. Forty-two recreationally active men volunteered to participate in this study. Participants were randomly assigned to 1 of 3 groups: Cr (n = 16), 10 g Cr + 10 g dextrose; placebo (PL, n = 16), 20 g dextrose; control (CON, n = 10), no treatment. Before and after supplementation, each participant performed a maximal oxygen consumption test VO2PEAK on a cycle ergometer to establish peak power output (PPO). Participants then completed a CP test involving 3 exercise bouts with the workloads set as a percentage of their PPO to determine CP and AWC. After a 2-week familiarization period of training and supplementing, PPO, CP, and AWC were remeasured before an additional 4 weeks of HIIT and supplementation were completed. Training consisted of 5 sets of 2-minute exercise bouts with 1 minute rest in between performed on the cycle ergometer, with intensities based on PPO. A significant improvement in CP was observed in the Cr group (6.72% +/- 2.54%), whereas PL showed no significant change (3.87% +/- 2.30%), and CON significantly decreased (6.27% +/- 2.38%). Furthermore, no changes in AWC were observed in any of the groups after treatment. The current findings suggest that Cr supplementation may enhance the effects of intense interval endurance training on endurance performance changes.

Effect of Ferric Carboxymaltose on Exercise Capacity in Patients With Chronic Heart Failure and Iron Deficiency.

PubMed

van Veldhuisen, Dirk J; Ponikowski, Piotr; van der Meer, Peter; Metra, Marco; Böhm, Michael; Doletsky, Artem; Voors, Adriaan A; Macdougall, Iain C; Anker, Stefan D; Roubert, Bernard; Zakin, Lorraine; Cohen-Solal, Alain

2017-10-10

Iron deficiency is common in patients with heart failure (HF) and is associated with reduced exercise capacity and poor outcomes. Whether correction of iron deficiency with (intravenous) ferric carboxymaltose (FCM) affects peak oxygen consumption [peak VO 2 ], an objective measure of exercise intolerance in HF, has not been examined. We studied patients with systolic HF (left ventricular ejection fraction ≤45%) and mild to moderate symptoms despite optimal HF medication. Patients were randomized 1:1 to treatment with FCM for 24 weeks or standard of care. The primary end point was the change in peak VO 2 from baseline to 24 weeks. Secondary end points included the effect on hematinic and cardiac biomarkers, quality of life, and safety. For the primary analysis, patients who died had a value of 0 imputed for 24-week peak VO 2 . Additional sensitivity analyses were performed to determine the impact of imputation of missing peak VO 2 data. A total of 172 patients with HF were studied and received FCM (n=86) or standard of care (control group, n=86). At baseline, the groups were well matched; mean age was 64 years, 75% were male, mean left ventricular ejection fraction was 32%, and peak VO 2 was 13.5 mL/min/kg. FCM significantly increased serum ferritin and transferrin saturation. At 24 weeks, peak VO 2 had decreased in the control group (least square means -1.19±0.389 mL/min/kg) but was maintained on FCM (-0.16±0.387 mL/min/kg; P =0.020 between groups). In a sensitivity analysis, in which missing data were not imputed, peak VO 2 at 24 weeks decreased by -0.63±0.375 mL/min/kg in the control group and by -0.16±0.373 mL/min/kg in the FCM group; P =0.23 between groups). Patients' global assessment and functional class as assessed by the New York Heart Association improved on FCM versus standard of care. Treatment with intravenous FCM in patients with HF and iron deficiency improves iron stores. Although a favorable effect on peak VO 2 was observed on FCM, compared with standard of care in the primary analysis, this effect was highly sensitive to the imputation strategy for peak VO 2 among patients who died. Whether FCM is associated with an improved outcome in these high-risk patients needs further study. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01394562. © 2017 The Authors.

Effect of Ferric Carboxymaltose on Exercise Capacity in Patients With Chronic Heart Failure and Iron Deficiency

PubMed Central

Ponikowski, Piotr; van der Meer, Peter; Metra, Marco; Böhm, Michael; Doletsky, Artem; Voors, Adriaan A.; Macdougall, Iain C.; Anker, Stefan D.; Roubert, Bernard; Zakin, Lorraine; Cohen-Solal, Alain

2017-01-01

Background: Iron deficiency is common in patients with heart failure (HF) and is associated with reduced exercise capacity and poor outcomes. Whether correction of iron deficiency with (intravenous) ferric carboxymaltose (FCM) affects peak oxygen consumption [peak VO2], an objective measure of exercise intolerance in HF, has not been examined. Methods: We studied patients with systolic HF (left ventricular ejection fraction ≤45%) and mild to moderate symptoms despite optimal HF medication. Patients were randomized 1:1 to treatment with FCM for 24 weeks or standard of care. The primary end point was the change in peak VO2 from baseline to 24 weeks. Secondary end points included the effect on hematinic and cardiac biomarkers, quality of life, and safety. For the primary analysis, patients who died had a value of 0 imputed for 24-week peak VO2. Additional sensitivity analyses were performed to determine the impact of imputation of missing peak VO2 data. Results: A total of 172 patients with HF were studied and received FCM (n=86) or standard of care (control group, n=86). At baseline, the groups were well matched; mean age was 64 years, 75% were male, mean left ventricular ejection fraction was 32%, and peak VO2 was 13.5 mL/min/kg. FCM significantly increased serum ferritin and transferrin saturation. At 24 weeks, peak VO2 had decreased in the control group (least square means −1.19±0.389 mL/min/kg) but was maintained on FCM (−0.16±0.387 mL/min/kg; P=0.020 between groups). In a sensitivity analysis, in which missing data were not imputed, peak VO2 at 24 weeks decreased by −0.63±0.375 mL/min/kg in the control group and by −0.16±0.373 mL/min/kg in the FCM group; P=0.23 between groups). Patients’ global assessment and functional class as assessed by the New York Heart Association improved on FCM versus standard of care. Conclusions: Treatment with intravenous FCM in patients with HF and iron deficiency improves iron stores. Although a favorable effect on peak VO2 was observed on FCM, compared with standard of care in the primary analysis, this effect was highly sensitive to the imputation strategy for peak VO2 among patients who died. Whether FCM is associated with an improved outcome in these high-risk patients needs further study. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01394562. PMID:28701470

ZT Optimization: An Application Focus

PubMed Central

Tuley, Richard; Simpson, Kevin

2017-01-01

Significant research has been performed on the challenge of improving thermoelectric materials, with maximum peak figure of merit, ZT, the most common target. We use an approximate thermoelectric material model, matched to real materials, to demonstrate that when an application is known, average ZT is a significantly better optimization target. We quantify this difference with some examples, with one scenario showing that changing the doping to increase peak ZT by 19% can lead to a performance drop of 16%. The importance of average ZT means that the temperature at which the ZT peak occurs should be given similar weight to the value of the peak. An ideal material for an application operates across the maximum peak ZT, otherwise maximum performance occurs when the peak value is reduced in order to improve the peak position. PMID:28772668

Psychological Preparation for Peak Performance in Sports Competition

ERIC Educational Resources Information Center

Ohuruogu, Ben; Jonathan, Ugwuanyi I.; Ikechukwu, Ugwu Jude

2016-01-01

This paper attempts to make an overview of various techniques, sport psychologist adopt in psychological preparation of athletes for peak performance. To attain peak performance in sports competitions, coaches and athletes should not base their prospect on physical training on sport skills alone rather should integrate both the mental and physical…

Fatigue Index and Fatigue Rate during an Anaerobic Performance under Hypohydrations

PubMed Central

Naharudin, Mohamed Nashrudin; Yusof, Ashril

2013-01-01

Background Since hypohydration commonly occurs in sports, studies on anaerobic exercise performance under this condition have been extensively carried out. When describing anaerobic performance, authors usually refer to a drop in anaerobic performance as fatigue index (FI) which is conventionally calculated using peak and low power data points. Meanwhile, another possible method in explaining anaerobic fatigue is using the rate constant which is derived from the exponential decline of power output known as fatigue rate (FR). Few studies have demonstrated that there was no change in anaerobic performance under mild hypohydrations. Purpose This study aimed to compare the kinetics of power output using FI and FR of an anaerobic performance (Wingate test) under 2, 3 and 4% state of hypohydrations. Method Thirty two collegiate cyclists (age  = 22±2 years; body weight  = 71.45±3.43 kg; height  = 173.23±0.04 cm) were matched using their baseline anaerobic peak power (APP) then randomly divided into 4 groups of EU (euhydrated), 2H, 3H and 4H respectively. Results As expected the, FI, APP, anaerobic lower power (ALP) and rating of perceived exertion (RPE) did not show significant differences between and within the groups. However, the FR in 3H (0.018±0.005s−1) and 4H (0.019±0.010s−1) were significantly lower than EU (0.033±0.012s−1). Post-test FR also showed significant reduction in 3H and 4H compared to their pre-test values (p<0.05). Conclusion Despite the lack of changes in APP and RPE, subjects in 3H and 4H showed evidence of lower reduction of power output over time. The findings support earlier reports which showed no change in anaerobic performance under mild hypohydrations. The relatively lower FR suggests higher drive in maintaining power output under hypohydrations of 3 and 4% body weight. PMID:24204790

Training Lessons Learned from Peak Performance Episodes

DTIC Science & Technology

1986-06-01

PEAK PERFORMAN4CE Fina Report- EPSOESOctober 1984-December 1985 % 6. PERFORMING ORG. REPORT NUMBER * 7. AUTHOR(@) 6. CONTRACT OR GRANT NUMBER(s) James...L. Fobes - 9. PERFORMING ORGANIZATION NAME AND) ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK U.S. Army Research Institute Field UnitAEA OKUINMER...peak performance indicates that three cogni- . tive components enable these episodes: psychological readiness (activating . optimal arousal and emotion

Long-term results after distal rectus femoris transfer as a part of multilevel surgery for the correction of stiff-knee gait in spastic diplegic cerebral palsy.

PubMed

Dreher, Thomas; Wolf, Sebastian I; Maier, Michael; Hagmann, Sébastien; Vegvari, Dóra; Gantz, Simone; Heitzmann, Daniel; Wenz, Wolfram; Braatz, Frank

2012-10-03

The evidence for distal rectus femoris transfer as a part of multilevel surgery for the correction of stiff-knee gait in children with spastic diplegic cerebral palsy is limited because of inconsistent outcomes reported in various studies and the lack of long-term evaluations. This study investigated the long-term results (mean, nine years) for fifty-three ambulatory patients with spastic diplegic cerebral palsy and stiff-knee gait treated with standardized distal rectus femoris transfer as a part of multilevel surgery. Standardized three-dimensional gait analysis and clinical examination were carried out before surgery and at one year and nine years after surgery. Patients with decreased peak knee flexion in swing phase who had distal rectus femoris transfer to correct the decreased peak knee flexion in swing phase (C-DRFT) were evaluated separately from those with normal or increased peak knee flexion in swing phase who had distal rectus femoris transfer done as a prophylactic procedure (P-DRFT). A significantly increased peak knee flexion in swing phase was found in the C-DRFT group one year after surgery, while a significant loss (15°) in peak knee flexion in swing phase was noted in the P-DRFT group. A slight but not significant increase in peak knee flexion in swing phase in both groups was noted at the time of the long-term follow-up. A significant improvement in timing of peak knee flexion in swing phase was only found for the C-DRFT group, and was maintained after nine years. Knee motion and knee flexion velocity were significantly increased in both groups and were maintained at long-term follow-up in the C-DRFT group, while the P-DRFT showed a deterioration of knee motion. Distal rectus femoris transfer is an effective procedure to treat stiff-knee gait featuring decreased peak knee flexion in swing phase and leads to a long-lasting increase of peak knee flexion in swing phase nine years after surgery. Patients with more involvement showed a greater potential to benefit from distal rectus femoris transfer. However, 18% of the patients showed a permanently poor response and 15% developed recurrence. In patients with severe knee flexion who underwent a prophylactic distal rectus femoris transfer, a significant loss in peak knee flexion in swing phase was noted and thus a prophylactic distal rectus femoris transfer may not be indicated in these patients. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Peak Oxygen Uptake during and after Long-duration Space Flight

NASA Technical Reports Server (NTRS)

Moore, Alan D., Jr.; Downs, Meghan E.; Lee, Stuart M. C.; Feiveson, Alan H.; Knudsen, Poul; Evetts, Simon N.; Ploutz-Snyder, Lori

2014-01-01

Aerobic capacity (VO2peak) previously has not been measured during or after long-duration spaceflight. PURPOSE: To measure VO2peak and submaximal exercise responses during and after International Space Station (ISS) missions. METHODS: Astronauts (9 M, 5 F: 49 +/- 5 yr, 175 +/- 7 cm, 77.2 +/- 15.1 kg, 40.6 +/- 6.4 mL/kg/min [mean +/-SD]) performed graded peak cycle tests 90 days before spaceflight, 15 d (FD15) after launch and every 30 d thereafter during flight, and 1 (R+1), 10 (R+10), and 30 d (R+30) after landing. Oxygen consumption (VO2) and heart rate (HR) were measured from rest to peak exercise, while cardiac output (Q), stroke volume (SV), and arterial-venous oxygen difference (a-vO2diff) were measured only during rest and submaximal exercise. Data were analyzed using mixed-model linear regression. Body mass contributed significantly to statistical models, and thus results are reported as modeled estimates for an average subject. RESULTS: Early inflight (FD15) VO2peak was 17% lower (95% CI = - 22%, -13%) than preflight. VO2peak increased during spaceflight (0.001 L/min/d, P = 0.02) but did not return to preflight levels. On R+1 VO2peak was 15% (95% CI = -19%, -10%) lower than preflight but recovered to within 2% of preflight by R+30 (95% CI = -6%, +3%). Peak HR was not significantly different from preflight at any time. Inflight submaximal VO2 and a-vO2diff were generally lower than preflight, but the Q vs. VO2 slope was unchanged. In contrast, the SV vs. VO2 slope was lower (P < 0.001), primarily due to elevated SV at rest, and the HR vs. VO2 slope was greater (P < 0.001), largely due to elevated HR during more intense exercise. On R+1 although the relationships between VO2 and Q, SV, and HR were not statistically different than preflight, resting and submaximal exercise SV was lower (P < 0.001), resting and submaximal exercise HR was higher (P < 0.002), and a-vO2diff was unchanged. HR and SV returned to preflight levels by R+30. CONCLUSION: In the average astronaut VO2peak was reduced during spaceflight and immediately after landing but factors contributing to lower VO2peak may be different during spaceflight and recovery. Maintaining Q while VO2 is reduced inflight may be suggestive of an elevated blood flow to vascular beds other than exercising muscles, but decreased SV after flight likely reduces Q at peak exertion.

Multiple polarization states of vector soliton in fiber laser

NASA Astrophysics Data System (ADS)

Chen, Weicheng; Xu, Wencheng; Cao, Hui; Han, Dingan

2007-11-01

Vector soliton is obtained in erbium-doped fiber laser via nonlinear polarization rotation techniques. In experiment, we observe the every 4- and 7-pulse sinusoidal peak modulation. Temporal pulse sinusoidal peak modulation owes to evolution behavior of vector solitons in multiple polarization states. The polarizer in the laser modulates the mode-locked pulses with different polarization states into periodical pulse train intensities modulation. Moreover, the increasing pumping power lead to the appearance of the harmonic pulses and change the equivalent beat length to accelerate the polarization rotation. When the laser cavity length is the n-th multiple ratios to the beat length to maintain the mode-locking, the mode-locked vector soliton is in n-th multiple polarization states, exhibiting every n-pulse sinusoidal peak modulation.

Yb3+-doped rod-type amplifiers with local adiabatic tapers for peak power scaling and beam quality improvement

NASA Astrophysics Data System (ADS)

Zhu, Yuan; Eschrich, Tina; Leich, Martin; Grimm, Stephan; Kobelke, Jens; Lorenz, Martin; Bartelt, Hartmut; Jäger, Matthias

2017-10-01

The use of short local tapers in large mode area fiber amplifiers is proposed for peak power scaling while maintaining good beam quality. To avoid modal distortions, the powder-sintering (REPUSIL) method was employed to obtain core materials with excellent refractive index homogeneity. First experiments with Yb3+-doped rod-type amplifiers delivered 2 ns pulses with peak powers of 540 kW and energies of 1.4 mJ for the untapered rod and 230 kW for the tapered rod (limited by facet damage). The beam quality improved from an M 2 value of approximately 10 to 3.5. The investigation of the taper structure indicates room for further improvement.

Optimizing cerebral perfusion pressure during fiberoptic bronchoscopy in severe head injury: effect of hyperventilation.

PubMed

Previgliano, I J; Ripoll, P I; Chiappero, G; Galíndez, F; Germani, L; González, D H; Ferrari, N; Hlavnicka, A; Purvis, C

2002-01-01

The aim of this study was to evaluate if Hyperventilation (HV) could avoid the Intracranial Pressure (ICP) peak that occurs during Fiberoptic Bronchoscopy (FB) in severely head injured patients. A Cerebral Perfusion Pressure (CPP) > 75 mmHg was maintained in 34 patients, with a subgroup randomized to receive controlled HV during FB. Measurements were done before the procedure, during maximum ICP values and 30 minutes after FB. The HV group had minor ICP values after FB, without differences in CPP and ICP peak values.

Cerebellar nodulectomy impairs spatial memory of vestibular and optokinetic stimulation in rabbits.

PubMed

Barmack, N H; Errico, P; Ferraresi, A; Fushiki, H; Pettorossi, V E; Yakhnitsa, V

2002-02-01

Natural vestibular and optokinetic stimulation were used to investigate the possible role of the cerebellar nodulus in the regulation and modification of reflexive eye movements in rabbits. The nodulus and folium 9d of the uvula were destroyed by surgical aspiration. Before and after nodulectomy the vertical and horizontal vestibuloocular reflexes (VVOR, HVOR) were measured during sinusoidal vestibular stimulation about the longitudinal (roll) and vertical (yaw) axes. Although the gain of the HVOR (G(HVOR) = peak eye movement velocity/peak head velocity) was not affected by the nodulectomy, the gain of the VVOR (G(VVOR)) was reduced. The gains of the vertical and horizontal optokinetic reflexes (G(VOKR), G(HOKR)) were measured during monocular, sinusoidal optokinetic stimulation (OKS) about the longitudinal and vertical axes. Following nodulectomy, there was no reduction in G(VOKR) or G(HOKR). Long-term binocular OKS was used to generate optokinetic afternystagmus, OKAN II, that lasts for hours. After OKAN II was induced, rabbits were subjected to static pitch and roll, to determine how the plane and velocity of OKAN II is influenced by a changing vestibular environment. During static pitch, OKAN II slow phase remained aligned with earth-horizontal. This was true for normal and nodulectomized rabbits. During static roll, OKAN II remained aligned with earth-horizontal in normal rabbits. During static roll in nodulectomized rabbits, OKAN II slow phase developed a centripetal vertical drift. We examined the suppression and recovery of G(VVOR) following exposure to conflicting vertical OKS for 10-30 min. This vestibular-optokinetic conflict reduced G(VVOR) in both normal and nodulectomized rabbits. The time course of recovery of G(VVOR) after conflicting OKS was the same before and after nodulectomy. In normal rabbits, the head pitch angle, at which peak OKAN II velocity occurred, corresponded to the head pitch angle maintained during long-term OKS. If the head was maintained in a "pitched-up" or "pitched-down" orientation during long-term OKS, the subsequently measured OKAN II peak velocity occurred at the same orientation. This was not true for nodulectomized rabbits, who had OKAN II peak velocities at head pitch angles independent of those maintained during long-term OKS. We conclude that the nodulus participates in the regulation of compensatory reflexive movements. The nodulus also influences "remembered" head position in space derived from previous optokinetic and vestibular stimulation.

Distortion cancellation performance of miniature delay filters for feed-forward linear power amplifiers.

PubMed

Roy, Manas K

2002-11-01

The technique of feed-forward amplitude control has been widely used in the linearization of power amplifiers for wireless communication systems. In this technique, an error signal due to third order intermodulation distortion (IMD) is extracted, amplified, and used to correct the delayed main line distorted signal. For example, a miniature prototype base station for the Global System for Mobile Communications/Code Division Multiple Access (GSM/CDMA) cellular system uses feed-forward amplifiers with bulky and expensive coaxial cables, about 20 feet in length, to provide about 25 ns of delay. This paper shows alternate space-saving approaches of achieving these delays using three different types of delay filters: electromagnetic interdigital/lumped (<2.5"), ceramic (<1.8"), and ladder-type surface acoustic wave (SAW) (0.15"). The delay lines introduce phase and amplitude imbalance and delay mismatch in the linearization loop due to fabrication tolerances. These adversely affect the IMD cancellation. Using an RF system simulation tool, this paper critically compares the IMD cancellation performance achieved using the three technologies. Simulation results show that the optimization of delay mismatch can achieve the desired cancellation more easily than other parameters. It is shown that, if the critical system parameter (phase deviation from linearity), is maintained at <2.5 degrees peak-to-peak over a 20 MHz bandwidth in the frequency range 855 MHz to 875 MHz, one can achieve 25 dB of IMD cancellation performance. This paper concludes with the suggestion of a set of realistic specifications for a miniature delay filter for the low power loop of the feed-forward amplifier.

Performance of a Mach-Zehnder based analogue data recording system for use with the Gas Cherenkov Detector on the NIF

NASA Astrophysics Data System (ADS)

Carpenter, A. C.; Herrmann, H. W.; Beeman, B. V.; Lopez, F. E.; Hernandez, J. E.

2016-09-01

This paper covers the performance of a high speed analogue data transmission system. This system uses multiple Mach- Zehnder optical modulators to transmit and record fusion burn history data for the Gas Cherenkov Detector (GCD) on the National Ignition Facility. The GCD is designed to measure the burn duration of high energy gamma rays generated by Deuterium-Tritium (DT) interactions in the NIF. The burn duration of DT fusion can be as short as 10ps and the optical photons generated in the gas Cherenkov cell are measured using a vacuum photodiode with a FWHM of 55ps. A recording system with a 3dB bandwidth of ≥10GHz and a signal to noise ratio of ≥5 for photodiode output voltage of 50mV is presented. The data transmission system uses two or three Mach-Zehnder modulators and an RF amplifier to transmit data optically. This signal is received and recorded by optical to electrical converts and a high speed digital oscilloscope placed outside of the NIF Target Bay. Electrical performance metrics covered include signal to noise ratio (SNR), signal to peak to peak noise ratio, single shot dynamic range, shot to shot dynamic range, system bandwidth, scattering parameters, are shown. Design considerations such as self-test capabilities, the NIF radiation environment, upgrade compatibility, Mach-Zehnder (MZ) biasing, maintainability, and operating considerations for the use of MZs are covered. This data recording system will be used for the future upgrade of the GCD to be used with a Pulse Dilation PMT, currently under development.

Biomechanical mechanism of lateral trunk lean gait for knee osteoarthritis patients.

PubMed

Tokuda, Kazuki; Anan, Masaya; Takahashi, Makoto; Sawada, Tomonori; Tanimoto, Kenji; Kito, Nobuhiro; Shinkoda, Koichi

2018-01-03

The biomechanical mechanism of lateral trunk lean gait employed to reduce external knee adduction moment (KAM) for knee osteoarthritis (OA) patients is not well known. This mechanism may relate to the center of mass (COM) motion. Moreover, lateral trunk lean gait may affect motor control of the COM displacement. Uncontrolled manifold (UCM) analysis is an evaluation index used to understand motor control and variability of the motor task. Here we aimed to clarify the biomechanical mechanism to reduce KAM during lateral trunk lean gait and how motor variability controls the COM displacement. Twenty knee OA patients walked under two conditions: normal and lateral trunk lean gait conditions. UCM analysis was performed with respect to the COM displacement in the frontal plane. We also determined how the variability is structured with regards to the COM displacement as a performance variable. The peak KAM under lateral trunk lean gait was lower than that under normal gait. The reduced peak KAM observed was accompanied by medially shifted knee joint center, shortened distance of the center of pressure to knee joint center, and shortened distance of the knee-ground reaction force lever arm during the stance phase. Knee OA patients with lateral trunk lean gait could maintain kinematic synergy by utilizing greater segmental configuration variance to the performance variable. However, the COM displacement variability of lateral trunk lean gait was larger than that of normal gait. Our findings may provide clinical insights to effectively evaluate and prescribe gait modification training for knee OA patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Arterial blood pressure response to heavy resistance exercise.

PubMed

MacDougall, J D; Tuxen, D; Sale, D G; Moroz, J R; Sutton, J R

1985-03-01

The purpose of this study was to record the blood pressure response to heavy weight-lifting exercise in five experienced body builders. Blood pressure was directly recorded by means of a capacitance transducer connected to a catheter in the brachial artery. Intrathoracic pressure with the Valsalva maneuver was recorded as mouth pressure by having the subject maintain an open glottis while expiring against a column of Hg during the lifts. Exercises included single-arm curls, overhead presses, and both double- and single-leg presses performed to failure at 80, 90, 95, and 100% of maximum. Systolic and diastolic blood pressures rose rapidly to extremely high values during the concentric contraction phase for each lift and declined with the eccentric contraction. The greatest peak pressures occurred during the double-leg press where the mean value for the group was 320/250 mmHg, with pressures in one subject exceeding 480/350 mmHg. Peak pressures with the single-arm curl exercise reached a mean group value of 255/190 mmHg when repetitions were continued to failure. Mouth pressures of 30-50 Torr during a single maximum lift, or as subjects approached failure with a submaximal weight, indicate that a portion of the observed increase in blood pressure was caused by a Valsalva maneuver. It was concluded that when healthy young subjects perform weight-lifting exercises the mechanical compression of blood vessels combines with a potent pressor response and a Valsalva response to produce extreme elevations in blood pressure. Pressures are extreme even when exercise is performed with a relatively small muscle mass.

Muscle fatigue effects can be anticipated to reproduce a movement kinematics learned without fatigue.

PubMed

Monjo, Florian; Forestier, Nicolas

2016-12-17

Muscle fatigue modifies the gain between motor command magnitude and the mechanical muscular response. In other words, post-fatigue, central drives to the muscles must increase to maintain a particular submaximum mechanical output. In this study, we tested the hypothesis that this modified gain can be predicted by the central nervous system (CNS) during discrete ballistic movements. In two separate experiments, subjects were required to perform shoulder flexions in standing and sitting positions at submaximum target peak accelerations. They were assisted with visual feedback informing them on their performance after each trial. Shoulder flexions were performed before and after fatiguing protocols of the focal muscles. Acceleration signals, focal and postural muscle electromyograms (EMGs) were recorded. The results demonstrated that participants were able to reach with precision the target acceleration during the first movements post-fatigue at the cost of significant increase in focal motor command magnitude. Decreased variance of peak accelerations associated with increased focal command variability was observed post-fatigue. During the standing experiment, postural muscle EMGs revealed that anticipatory postural adjustments (APAs) scaled to focal movement acceleration post-fatigue. All these results support that fatigue effects are taken into account during movement planning. Indeed, given that no feedback could enable participants to adjust acceleration during movement, this capacity to anticipate fatigue effects is the exclusive result of feedforward processes. To account for this prediction capacity, we discuss the role of fatigue-related modifications in sensory inputs from the working muscles. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

47 CFR 73.664 - Determining operating power.

Code of Federal Regulations, 2010 CFR

2010-10-01

....664 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO... indications of a calibrated transmission line meter (responsive to peak power) located at the RF output terminals of the transmitter. The indications of the calibrated meter are used to observe and maintain the...

WIYN: A New Technology Telescope on Kitt Peak

NASA Astrophysics Data System (ADS)

Silva, David R.

1995-05-01

The WIYN Observatory, a joint venture between the University of Wisconsin (W), Indiana University (I), Yale University (Y), and the National Optical Astronomy Observatories (N), is a new technology alt-az 3.5m telescope located on Kitt Peak. Science operations are scheduled to begin during July 1995. WIYN has achieved site-limited delivered image quality (DIQ) through a combination of careful site selection, enclosure thermal control, and active optics techniques. The Observatory site was selected based on previous empirical observations of sub-arcsecond images. Heat from the enclosure is vented actively and passively: with 2 m/s winds, the observing chamber volume is exchanged roughly once per minute. The temperature and shape of the lightweight primary mirror, spun-cast by the Steward Observatory Mirror Lab, are maintained by control systems developed by NOAO. These systems maintain the mirror temperature within 0.2 deg C of ambient and the total delivered wavefront error within 150 nm RMS of the ideal. The measured WIYN median DIQ was 0.7'' FWHM for the period June 1994 through January 1995. The main facility instruments, the Multi-Object Spectrograph (MOS/Hydra) and the WIYN Imager, are currently being commissioned simultaneously at the two Nasymth foci. A f/6.3, 1 deg corrected beam is presented to MOS/Hydra while the beam presented to the Imager is corrected over 0.5 deg. The WIYN control system is based on a distributed network of real-time and time-sharing processors linked together by a low-bandwidth asynchronous message passing system. This architecture is robust, easily expandable, and amenable to remote operations. The baseline system was designed and implemented by the University of Wisconsin Controls Group. Current telescope performance and commissioning progress will be presented at the Meeting.

Novel wavelet threshold denoising method in axle press-fit zone ultrasonic detection

NASA Astrophysics Data System (ADS)

Peng, Chaoyong; Gao, Xiaorong; Peng, Jianping; Wang, Ai

2017-02-01

Axles are important part of railway locomotives and vehicles. Periodic ultrasonic inspection of axles can effectively detect and monitor axle fatigue cracks. However, in the axle press-fit zone, the complex interface contact condition reduces the signal-noise ratio (SNR). Therefore, the probability of false positives and false negatives increases. In this work, a novel wavelet threshold function is created to remove noise and suppress press-fit interface echoes in axle ultrasonic defect detection. The novel wavelet threshold function with two variables is designed to ensure the precision of optimum searching process. Based on the positive correlation between the correlation coefficient and SNR and with the experiment phenomenon that the defect and the press-fit interface echo have different axle-circumferential correlation characteristics, a discrete optimum searching process for two undetermined variables in novel wavelet threshold function is conducted. The performance of the proposed method is assessed by comparing it with traditional threshold methods using real data. The statistic results of the amplitude and the peak SNR of defect echoes show that the proposed wavelet threshold denoising method not only maintains the amplitude of defect echoes but also has a higher peak SNR.

Triboelectric-Based Transparent Secret Code.

PubMed

Yuan, Zuqing; Du, Xinyu; Li, Nianwu; Yin, Yingying; Cao, Ran; Zhang, Xiuling; Zhao, Shuyu; Niu, Huidan; Jiang, Tao; Xu, Weihua; Wang, Zhong Lin; Li, Congju

2018-04-01

Private and security information for personal identification requires an encrypted tool to extend communication channels between human and machine through a convenient and secure method. Here, a triboelectric-based transparent secret code (TSC) that enables self-powered sensing and information identification simultaneously in a rapid process method is reported. The transparent and hydrophobic TSC can be conformed to any cambered surface due to its high flexibility, which extends the application scenarios greatly. Independent of the power source, the TSC can induce obvious electric signals only by surface contact. This TSC is velocity-dependent and capable of achieving a peak voltage of ≈4 V at a resistance load of 10 MΩ and a sliding speed of 0.1 m s -1 , according to a 2 mm × 20 mm rectangular stripe. The fabricated TSC can maintain its performance after reciprocating rolling for about 5000 times. The applications of TSC as a self-powered code device are demonstrated, and the ordered signals can be recognized through the height of the electric peaks, which can be further transferred into specific information by the processing program. The designed TSC has great potential in personal identification, commodity circulation, valuables management, and security defense applications.

Spatial relationship between bone formation and mechanical stimulus within cortical bone: Combining 3D fluorochrome mapping and poroelastic finite element modelling.

PubMed

Carrieroa, A; Pereirab, A F; Wilson, A J; Castagno, S; Javaheri, B; Pitsillides, A A; Marenzana, M; Shefelbine, S J

2018-06-01

Bone is a dynamic tissue and adapts its architecture in response to biological and mechanical factors. Here we investigate how cortical bone formation is spatially controlled by the local mechanical environment in the murine tibia axial loading model (C57BL/6). We obtained 3D locations of new bone formation by performing 'slice and view' 3D fluorochrome mapping of the entire bone and compared these sites with the regions of high fluid velocity or strain energy density estimated using a finite element model, validated with ex-vivo bone surface strain map acquired ex-vivo using digital image correlation. For the comparison, 2D maps of the average bone formation and peak mechanical stimulus on the tibial endosteal and periosteal surface across the entire cortical surface were created. Results showed that bone formed on the periosteal and endosteal surface in regions of high fluid flow. Peak strain energy density predicted only the formation of bone periosteally. Understanding how the mechanical stimuli spatially relates with regions of cortical bone formation in response to loading will eventually guide loading regime therapies to maintain or restore bone mass in specific sites in skeletal pathologies.

Effects of Modified Multistage Field Test on Performance and Physiological Responses in Wheelchair Basketball Players

PubMed Central

Weissland, Thierry; Faupin, Arnaud; Borel, Benoit; Berthoin, Serge; Leprêtre, Pierre-Marie

2015-01-01

A bioenergetical analysis of manoeuvrability and agility performance for wheelchair players is inexistent. It was aimed at comparing the physiological responses and performance obtained from the octagon multistage field test (MFT) and the modified condition in “8 form” (MFT-8). Sixteen trained wheelchair basketball players performed both tests in randomized condition. The levels performed (end-test score), peak values of oxygen uptake (VO2peak), minute ventilation (VEpeak), heart rate (HRpeak), peak and relative blood lactate (Δ[Lact−] = peak – rest values), and the perceived rating exertion (RPE) were measured. MFT-8 induced higher VO2peak and VEpeak values compared to MFT (VO2peak: 2.5 ± 0.6 versus 2.3 ± 0.6 L·min−1 and VEpeak: 96.3 ± 29.1 versus 86.6 ± 23.4 L·min−1; P < 0.05) with no difference in other parameters. Significant relations between VEpeak and end-test score were correlated for both field tests (P < 0.05). At exhaustion, MFT attained incompletely VO2peak and VEpeak. Among experienced wheelchair players, MFT-8 had no effect on test performance but generates higher physiological responses than MFT. It could be explained by demands of wheelchair skills occurring in 8 form during the modified condition. PMID:25802841

The Influence of a Bout of Exertion on Novice Barefoot Running Dynamics

PubMed Central

Hashish, Rami; Samarawickrame, Sachithra D.; Baker, Lucinda; Salem, George J.

2016-01-01

Barefoot, forefoot strike (FFS) running has recently risen in popularity. Relative to shod, rear-foot strike (RFS) running, employing a FFS is associated with heightened triceps surae muscle activation and ankle mechanical demand. Novice to this pattern, it is plausible that habitually shod RFS runners exhibit fatigue to the triceps surae when acutely transitioning to barefoot running, thereby limiting their ability to attenuate impact. Therefore, the purpose was to determine how habitually shod RFS runners respond to an exertion bout of barefoot running, operationally defined as a barefoot run 20% of mean daily running distance. Twenty-one RFS runners performed novice barefoot running, before and after exertion. Ankle peak torque, triceps surae EMG median frequency, foot-strike patterns, joint energy absorption, and loading rates were evaluated. Of the 21 runners, 6 maintained a RFS, 10 adopted a mid-foot strike (MFS), and 5 adopted a FFS during novice barefoot running. In-response to exertion, MFS and FFS runners demonstrated reductions in peak torque, median frequency, and ankle energy absorption, and an increase in loading rate. RFS runners demonstrated reductions in peak torque and loading rate. These results indicate that a short bout of running may elicit fatigue to novice barefoot runners, limiting their ability to attenuate impact. Key points In response to exertion, novice barefoot runners demonstrate fatigue to their soleus. In response to exertion, novice barefoot runners demonstrate a reduction in ankle energy absorption In response to exertion, novice barefoot runners demonstrate an increase in loading rate PMID:27274672

The Influence of a Bout of Exertion on Novice Barefoot Running Dynamics.

PubMed

Hashish, Rami; Samarawickrame, Sachithra D; Baker, Lucinda; Salem, George J

2016-06-01

Barefoot, forefoot strike (FFS) running has recently risen in popularity. Relative to shod, rear-foot strike (RFS) running, employing a FFS is associated with heightened triceps surae muscle activation and ankle mechanical demand. Novice to this pattern, it is plausible that habitually shod RFS runners exhibit fatigue to the triceps surae when acutely transitioning to barefoot running, thereby limiting their ability to attenuate impact. Therefore, the purpose was to determine how habitually shod RFS runners respond to an exertion bout of barefoot running, operationally defined as a barefoot run 20% of mean daily running distance. Twenty-one RFS runners performed novice barefoot running, before and after exertion. Ankle peak torque, triceps surae EMG median frequency, foot-strike patterns, joint energy absorption, and loading rates were evaluated. Of the 21 runners, 6 maintained a RFS, 10 adopted a mid-foot strike (MFS), and 5 adopted a FFS during novice barefoot running. In-response to exertion, MFS and FFS runners demonstrated reductions in peak torque, median frequency, and ankle energy absorption, and an increase in loading rate. RFS runners demonstrated reductions in peak torque and loading rate. These results indicate that a short bout of running may elicit fatigue to novice barefoot runners, limiting their ability to attenuate impact. Key pointsIn response to exertion, novice barefoot runners demonstrate fatigue to their soleus.In response to exertion, novice barefoot runners demonstrate a reduction in ankle energy absorptionIn response to exertion, novice barefoot runners demonstrate an increase in loading rate.

Visual and non-visual control of landing movements in humans

PubMed Central

Santello, Marco; McDonagh, Martin J N; Challis, John H

2001-01-01

The role of vision in controlling leg muscle activation in landing from a drop was investigated. Subjects (n = 8) performed 10 drops from four heights (0.2, 0.4, 0.6 and 0.8 m) with and without vision. Drop height was maintained constant throughout each block of trials to allow adaptation. The aim of the study was to assess the extent to which proprioceptive and vestibular information could substitute for the lack of vision in adapting landing movements to different heights. At the final stages of the movement, subjects experienced similar peak centre of body mass (CM) displacements and joint rotations, regardless of the availability of vision. This implies that subjects were able to adapt the control of landing to different heights. The amplitude and timing of electromyographic signals from the leg muscles scaled to drop height in a similar fashion with and without vision. However, variables measured throughout the execution of the movement indicated important differences. Without vision, landings were characterised by 10 % larger ground reaction forces, 10 % smaller knee joint rotations, different time lags between peak joint rotations, and more variable ground reaction forces and times to peak CM displacement. We conclude that non-visual sensory information (a) could not fully compensate for the lack of continuous visual feedback and (b) this non-visual information was used to reorganise the motor output. These results suggest that vision is important for the very accurate timing of muscle activity onset and the kinematics of landing. PMID:11711583

Returners Exhibit Greater Jumping Performance Improvements During a Peaking Phase Compared With New Players on a Volleyball Team.

PubMed

Bazyler, Caleb D; Mizuguchi, Satoshi; Kavanaugh, Ashley A; McMahon, John J; Comfort, Paul; Stone, Michael H

2018-06-21

To determine if jumping-performance changes during a peaking phase differed among returners and new players on a female collegiate volleyball team and to determine which variables best explained the variation in performance changes. Fourteen volleyball players were divided into 2 groups-returners (n = 7) and new players (n = 7)-who completed a 5-wk peaking phase prior to conference championships. Players were tested at baseline before the preseason on measures of the vastus lateralis cross-sectional area using ultrasonography, estimated back-squat 1-repetition maximum, countermovement jump height (JH), and relative peak power on a force platform. Jumping performance, rating of perceived exertion training load, and sets played were recorded weekly during the peaking phase. There were moderate to very large (P < .01, Glass Δ = 1.74) and trivial to very large (P = .07, Δ = 1.09) differences in JH and relative peak power changes in favor of returners over new players, respectively, during the peaking phase. Irrespective of group, 7 of 14 players achieved peak JH 2 wk after the initial overreach. The number of sets played (r = .78, P < .01) and the athlete's preseason relative 1-repetition maximum (r = .54, P = .05) were the strongest correlates of JH changes during the peaking phase. Returners achieved greater improvements in jumping performance during the peaking phase compared with new players, which may be explained by the returners' greater relative maximal strength, time spent competing, and training experience. Thus, volleyball and strength coaches should consider these factors when prescribing training during a peaking phase to ensure their players are prepared for important competitions.

Peak picking and the assessment of separation performance in two-dimensional high performance liquid chromatography.

PubMed

Stevenson, Paul G; Mnatsakanyan, Mariam; Guiochon, Georges; Shalliker, R Andrew

2010-07-01

An algorithm was developed for 2DHPLC that automated the process of peak recognition, measuring their retention times, and then subsequently plotting the information in a two-dimensional retention plane. Following the recognition of peaks, the software then performed a series of statistical assessments of the separation performance, measuring for example, correlation between dimensions, peak capacity and the percentage of usage of the separation space. Peak recognition was achieved by interpreting the first and second derivatives of each respective one-dimensional chromatogram to determine the 1D retention times of each solute and then compiling these retention times for each respective fraction 'cut'. Due to the nature of comprehensive 2DHPLC adjacent cut fractions may contain peaks common to more than one cut fraction. The algorithm determined which components were common in adjacent cuts and subsequently calculated the peak maximum profile by interpolating the space between adjacent peaks. This algorithm was applied to the analysis of a two-dimensional separation of an apple flesh extract separated in a first dimension comprising a cyano stationary phase and an aqueous/THF mobile phase as the first dimension and a second dimension comprising C18-Hydro with an aqueous/MeOH mobile phase. A total of 187 peaks were detected.

Method and system for detecting an explosive

DOEpatents

Reber, Edward L.; Rohde, Kenneth W.; Blackwood, Larry G.

2010-12-07

A method and system for detecting at least one explosive in a vehicle using a neutron generator and a plurality of NaI detectors. Spectra read from the detectors is calibrated by performing Gaussian peak fitting to define peak regions, locating a Na peak and an annihilation peak doublet, assigning a predetermined energy level to one peak in the doublet, and predicting a hydrogen peak location based on a location of at least one peak of the doublet. The spectra are gain shifted to a common calibration, summed for respective groups of NaI detectors, and nitrogen detection analysis performed on the summed spectra for each group.

Electrochemical Properties of Poly(Anthraquinonyl Sulfide)/Graphene Sheets Composites as Electrode Materials for Electrochemical Capacitors.

PubMed

Lee, Wonkyun; Suzuki, Shinya; Miyayama, Masaru

2014-07-30

Poly(anthraquinonyl sulfide) (PAQS)/graphene sheets (GSs) composite was synthesized through in situ polymerization to evaluate its performance as an electrode material for electrochemical capacitors. PAQS was successfully synthesized in the presence of GSs with uniform distribution. PAQS/GSs showed a pair of reversible redox peaks at around 0 V ( vs. Ag/AgCl). The specific capacitance of PAQS/GSs was 349 F·g -1 (86 mAh·g -1 ) at a current density of 500 mA·g -1 , and a capacitance of 305 F·g -1 was maintained even at a high current density of 5000 mA·g -1 . The in situ polymerization of PAQS with GSs facilitated their interaction and enabled faster charge transfer and redox reaction, resulting in enhanced electrode properties.

Active stabilization of a diode laser injection lock.

PubMed

Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

2016-06-01

We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.

Echidna Mark II: one giant leap for 'tilting spine' fibre positioning technology

NASA Astrophysics Data System (ADS)

Gilbert, James; Dalton, Gavin

2016-07-01

The Australian Astronomical Observatory's 'tilting spine' fibre positioning technology has been redeveloped to provide superior performance in a smaller package. The new design offers demonstrated closed-loop positioning errors of <2.8 μm RMS in only five moves ( 10 s excluding metrology overheads) and an improved capacity for open-loop tracking during observations. Tilt-induced throughput losses have been halved by lengthening spines while maintaining excellent accuracy. New low-voltage multilayer piezo actuator technology has reduced a spine's peak drive amplitude from 150V to <10V, simplifying the control electronics design, reducing the system's overall size, and improving modularity. Every spine is now a truly independent unit with a dedicated drive circuit and no restrictions on the timing or direction of fibre motion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser’s transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399more » nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.« less

The effects of baseball bat mass properties on swing mechanics, ground reaction forces, and swing timing.

PubMed

Laughlin, Walter A; Fleisig, Glenn S; Aune, Kyle T; Diffendaffer, Alek Z

2016-01-01

Swing trajectory and ground reaction forces (GRF) of 30 collegiate baseball batters hitting a pitched ball were compared between a standard bat, a bat with extra weight about its barrel, and a bat with extra weight in its handle. It was hypothesised that when compared to a standard bat, only a handle-weighted bat would produce equivalent bat kinematics. It was also hypothesised that hitters would not produce equivalent GRFs for each weighted bat, but would maintain equivalent timing when compared to a standard bat. Data were collected utilising a 500 Hz motion capture system and 1,000 Hz force plate system. Data between bats were considered equivalent when the 95% confidence interval of the difference was contained entirely within ±5% of the standard bat mean value. The handle-weighted bat had equivalent kinematics, whereas the barrel-weighted bat did not. Both weighted bats had equivalent peak GRF variables. Neither weighted bat maintained equivalence in the timing of bat kinematics and some peak GRFs. The ability to maintain swing kinematics with a handle-weighted bat may have implications for swing training and warm-up. However, altered timings of kinematics and kinetics require further research to understand the implications on returning to a conventionally weighted bat.

Motion Perception and Manual Control Performance During Passive Tilt and Translation Following Space Flight

NASA Technical Reports Server (NTRS)

Clement, Gilles; Wood, Scott J.

2010-01-01

This joint ESA-NASA study is examining changes in motion perception following Space Shuttle flights and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data has been collected on 5 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s) combined with body translation (12-22 cm, peak-to-peak) is utilized to elicit roll-tilt perception (equivalent to 20 deg, peak-to-peak). A forward-backward moving sled (24-390 cm, peak-to-peak) with or without chair tilting in pitch is utilized to elicit pitch tilt perception (equivalent to 20 deg, peak-to-peak). These combinations are elicited at 0.15, 0.3, and 0.6 Hz for evaluating the effect of motion frequency on tilt-translation ambiguity. In both devices, a closed-loop nulling task is also performed during pseudorandom motion with and without vibrotactile feedback of tilt. All tests are performed in complete darkness. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for translation motion perception to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. The results of this study indicate that post-flight recovery of motion perception and manual control performance is complete within 8 days following short-duration space missions. Vibrotactile feedback of tilt improves manual control performance both before and after flight.

A prototype automatic phase compensation module

NASA Technical Reports Server (NTRS)

Terry, John D.

1992-01-01

The growing demands for high gain and accurate satellite communication systems will necessitate the utilization of large reflector systems. One area of concern of reflector based satellite communication is large scale surface deformations due to thermal effects. These distortions, when present, can degrade the performance of the reflector system appreciable. This performance degradation is manifested by a decrease in peak gain, and increase in sidelobe level, and pointing errors. It is essential to compensate for these distortion effects and to maintain the required system performance in the operating space environment. For this reason the development of a technique to offset the degradation effects is highly desirable. Currently, most research is direct at developing better material for the reflector. These materials have a lower coefficient of linear expansion thereby reducing the surface errors. Alternatively, one can minimize the distortion effects of these large scale errors by adaptive phased array compensation. Adaptive phased array techniques have been studied extensively at NASA and elsewhere. Presented in this paper is a prototype automatic phase compensation module designed and built at NASA Lewis Research Center which is the first stage of development for an adaptive array compensation module.

Anaerobic treatment of rice winery wastewater in an upflow filter packed with steel slag under different hydraulic loading conditions.

PubMed

Jo, Yeadam; Kim, Jaai; Hwang, Seokhwan; Lee, Changsoo

2015-10-01

Rice-washing drainage (RWD), a strong organic wastewater, was anaerobically treated using an upflow filter filled with blast-furnace slag. The continuous performance of the reactor was examined at varying hydraulic retention times (HRTs). The reactor achieved 91.7% chemical oxygen demand removal (CODr) for a 10-day HRT (0.6 g COD/Ld organic loading rate) and maintained fairly stable performance until the HRT was shortened to 2.2 days (CODr > 84%). Further decreases in HRT caused process deterioration (CODr < 50% and pH < 5.5 for a 0.7-day HRT). The methane production rate increased with decreasing HRT to reach the peak level for a 1.3-day HRT, whereas the yield was significantly greater for 3.4-day or longer HRTs. The substrate removal and methane production kinetics were successfully evaluated, and the generated kinetic models produced good performance predictions. The methanogenic activity of the reactor likely relies on the filter biofilm, with Methanosaeta being the main driver. Copyright © 2015 Elsevier Ltd. All rights reserved.

The age of peak performance in Ironman triathlon: a cross-sectional and longitudinal data analysis

PubMed Central

2013-01-01

Background The aims of the present study were, firstly, to investigate in a cross-sectional analysis the age of peak Ironman performance within one calendar year in all qualifiers for Ironman Hawaii and Ironman Hawaii; secondly, to determine in a longitudinal analysis on a qualifier for Ironman Hawaii whether the age of peak Ironman performance and Ironman performance itself change across years; and thirdly, to determine the gender difference in performance. Methods In a cross-sectional analysis, the age of the top ten finishers for all qualifier races for Ironman Hawaii and Ironman Hawaii was determined in 2010. For a longitudinal analysis, the age and the performance of the annual top ten female and male finishers in a qualifier for Ironman Hawaii was determined in Ironman Switzerland between 1995 and 2010. Results In 19 of the 20 analyzed triathlons held in 2010, there was no difference in the age of peak Ironman performance between women and men (p > 0.05). The only difference in the age of peak Ironman performance between genders was in ‘Ironman Canada’ where men were older than women (p = 0.023). For all 20 races, the age of peak Ironman performance was 32.2 ± 1.5 years for men and 33.0 ± 1.6 years for women (p > 0.05). In Ironman Switzerland, there was no difference in the age of peak Ironman performance between genders for top ten women and men from 1995 to 2010 (F = 0.06, p = 0.8). The mean age of top ten women and men was 31.4 ± 1.7 and 31.5 ± 1.7 years (Cohen's d = 0.06), respectively. The gender difference in performance in the three disciplines and for overall race time decreased significantly across years. Men and women improved overall race times by approximately 1.2 and 4.2 min/year, respectively. Conclusions Women and men peak at a similar age of 32–33 years in an Ironman triathlon with no gender difference. In a qualifier for Ironman Hawaii, the age of peak Ironman performance remained unchanged across years. In contrast, gender differences in performance in Ironman Switzerland decreased during the studied period, suggesting that elite female Ironman triathletes might still narrow the gender gap in the future. PMID:24004814

Active feed array compensation for reflector antenna surface distortions. Ph.D. Thesis - Akron Univ., Ohio

NASA Technical Reports Server (NTRS)

Acosta, Roberto J.

1988-01-01

The feasibility of electromagnetic compensation for reflector antenna surface distortions is investigated. The performance characteristics of large satellite communication reflector antenna systems degrade as the reflector surface distorts, mainly due to thermal effects from solar radiation. The technique developed can be used to maintain the antenna boresight directivity and sidelobe level independent of thermal effects on the reflector surface. With the advent of monolithic microwave integrated circuits (MMIC), a greater flexibility in array fed reflector antenna systems can be achieved. MMIC arrays provide independent control of amplitude and phase for each of the many radiating elements in the feed array. By assuming a known surface distortion profile, a simulation study is carried out to examine the antenna performance as a function of feed array size and number of elements. Results indicate that the compensation technique can effectively control boresight directivity and sidelobe level under peak surface distortion in the order of tenth of a wavelength.

Performance of GAASP/GAAS Superlattice Photocathodes in High Energy Experiments using Polarized Electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brachmann, A.; Clendenin, J.E.; Maruyama, T.

2006-02-27

The GaAsP/GaAs strained superlattice photocathode structure has proven to be a significant advance for polarized electron sources operating with high peak currents per microbunch and relatively low duty factor. This is the characteristic type of operation for SLAC and is also planned for the ILC. This superlattice structure was studied at SLAC [1], and an optimum variation was chosen for the final stage of E-158, a high-energy parity violating experiment at SLAC. Following E-158, the polarized source was maintained on standby with the cathode being re-cesiated about once a week while a thermionic gun, which is installed in parallel withmore » the polarized gun, supplied the linac electron beams. However, in the summer of 2005, while the thermionic gun was disabled, the polarized electron source was again used to provide electron beams for the linac. The performance of the photocathode 24 months after its only activation is described and factors making this possible are discussed.« less

Discrimination of serum Raman spectroscopy between normal and colorectal cancer

NASA Astrophysics Data System (ADS)

Li, Xiaozhou; Yang, Tianyue; Yu, Ting; Li, Siqi

2011-07-01

Raman spectroscopy of tissues has been widely studied for the diagnosis of various cancers, but biofluids were seldom used as the analyte because of the low concentration. Herein, serum of 30 normal people, 46 colon cancer, and 44 rectum cancer patients were measured Raman spectra and analyzed. The information of Raman peaks (intensity and width) and that of the fluorescence background (baseline function coefficients) were selected as parameters for statistical analysis. Principal component regression (PCR) and partial least square regression (PLSR) were used on the selected parameters separately to see the performance of the parameters. PCR performed better than PLSR in our spectral data. Then linear discriminant analysis (LDA) was used on the principal components (PCs) of the two regression method on the selected parameters, and a diagnostic accuracy of 88% and 83% were obtained. The conclusion is that the selected features can maintain the information of original spectra well and Raman spectroscopy of serum has the potential for the diagnosis of colorectal cancer.

Minimum maximum temperature gradient coil design.

PubMed

While, Peter T; Poole, Michael S; Forbes, Larry K; Crozier, Stuart

2013-08-01

Ohmic heating is a serious problem in gradient coil operation. A method is presented for redesigning cylindrical gradient coils to operate at minimum peak temperature, while maintaining field homogeneity and coil performance. To generate these minimaxT coil windings, an existing analytic method for simulating the spatial temperature distribution of single layer gradient coils is combined with a minimax optimization routine based on sequential quadratic programming. Simulations are provided for symmetric and asymmetric gradient coils that show considerable improvements in reducing maximum temperature over existing methods. The winding patterns of the minimaxT coils were found to be heavily dependent on the assumed thermal material properties and generally display an interesting "fish-eye" spreading of windings in the dense regions of the coil. Small prototype coils were constructed and tested for experimental validation and these demonstrate that with a reasonable estimate of material properties, thermal performance can be improved considerably with negligible change to the field error or standard figures of merit. © 2012 Wiley Periodicals, Inc.

Sol-gel transition of organogels observed by terahertz spectroscopy

NASA Astrophysics Data System (ADS)

Hoshina, Hiromichi; Ozaki, Atsumi; Itagaki, Yusuke; Yajima, Setsuko; Suzuki, Hal; Ishii, Shinya; Ishida, Misaki; Uchiyama, Tetsuji; Kimura, Keiichi; Otani, Chiko

2014-07-01

Terahertz (THz) absorption spectra of organogels consisting of (1R,2R)-1,2-bis(dodecanoylamino)cyclohexane/2-nitrophenyl octyl ether (RR-BDC/NPOE) and RR-BDC/n-dodecane were measured by Fourier-transform far-infrared (FT-FIR) spectroscopy. The vibrational peaks of the gels were observed at the same frequencies as those of the pure gelator, suggesting that the intermolecular structure around the Nsbnd H⋯Odbnd C hydrogen bond is maintained in the gel phase. Temperature-dependent spectroscopy showed a drastic spectral change at the sol-gel transition temperature, in which the vibrational peak at 3.5 THz disappears and a new peak appears at 2.9 THz. The change in THz vibrational frequency is indicative of the structural collapse of the hydrogen-bonded fibrous architecture in the sol phase.

Progression of language decline and cortical atrophy in subtypes of primary progressive aphasia.

PubMed

Rogalski, E; Cobia, D; Harrison, T M; Wieneke, C; Weintraub, S; Mesulam, M-M

2011-05-24

To examine the longitudinal course of primary progressive aphasia (PPA) over a 2-year period and to offer quantitative ranges of expected change that could be used to guide the design and evaluation of therapeutic intervention trials. Regional changes of cortical thickness and whole-brain cortical volume loss as well as neuropsychological language performance were assessed at baseline and 2 years later in 13 rigorously characterized patients who fulfilled research criteria for logopenic, agrammatic, and semantic PPA subtypes (6 PPA-L, 3 PPA-G, and 4 PPA-S). There was substantial progression of clinical deficits and cortical atrophy over 2 years. Neuropsychological language performance patterns lost the sharp distinctions that differentiated one PPA variant from another. Nonetheless, the subtype-specific differential impairment of word comprehension vs grammatical processing was largely maintained. Peak atrophy sites spread beyond the initial distinctive locations that characterized each of the 3 subtypes and displayed a more convergent distribution encompassing all 3 major components of the language network: the inferior frontal gyrus, the temporoparietal junction, and lateral temporal cortex. Despite the progression, overall peak atrophy remained lateralized to the left hemisphere. The results suggest that the unique features, which sharply differentiate the PPA variants at the early to middle stages, may lose their distinctiveness as the degeneration becomes more severe. Given the substantial atrophy over 2 years, PPA clinical trials may require fewer patients and shorter study durations than Alzheimer disease trials to detect significant therapeutic effects.

Progression of language decline and cortical atrophy in subtypes of primary progressive aphasia

PubMed Central

Cobia, D.; Harrison, T.M.; Wieneke, C.; Weintraub, S.; Mesulam, M.-M.

2011-01-01

Objectives: To examine the longitudinal course of primary progressive aphasia (PPA) over a 2-year period and to offer quantitative ranges of expected change that could be used to guide the design and evaluation of therapeutic intervention trials. Methods: Regional changes of cortical thickness and whole-brain cortical volume loss as well as neuropsychological language performance were assessed at baseline and 2 years later in 13 rigorously characterized patients who fulfilled research criteria for logopenic, agrammatic, and semantic PPA subtypes (6 PPA-L, 3 PPA-G, and 4 PPA-S). Results: There was substantial progression of clinical deficits and cortical atrophy over 2 years. Neuropsychological language performance patterns lost the sharp distinctions that differentiated one PPA variant from another. Nonetheless, the subtype-specific differential impairment of word comprehension vs grammatical processing was largely maintained. Peak atrophy sites spread beyond the initial distinctive locations that characterized each of the 3 subtypes and displayed a more convergent distribution encompassing all 3 major components of the language network: the inferior frontal gyrus, the temporoparietal junction, and lateral temporal cortex. Despite the progression, overall peak atrophy remained lateralized to the left hemisphere. Conclusions: The results suggest that the unique features, which sharply differentiate the PPA variants at the early to middle stages, may lose their distinctiveness as the degeneration becomes more severe. Given the substantial atrophy over 2 years, PPA clinical trials may require fewer patients and shorter study durations than Alzheimer disease trials to detect significant therapeutic effects. PMID:21606451

A longitudinal investigation into the functional and physical durability of insoles used for the preventive management of neuropathic diabetic feet.

PubMed

Paton, Joanne S; Stenhouse, Elizabeth; Bruce, Graham; Jones, Ray

2014-01-01

Insoles are commonly used to assist in the prevention of diabetic neuropathic foot ulceration. Insole replacement is often triggered only when foot lesions deteriorate, an indicator that functional performance is comprised and patients are exposed to unnecessary ulcer risk. We investigated the durability of insoles used for ulcer prevention in neuropathic diabetic feet over 12 months. Sixty neuropathic individuals with diabetes were provided with insoles and footwear. Insole durability over 12 months was evaluated using an in-shoe pressure measurement device and through repeated measurement of material depth at the first metatarsal head and the heel seat. Analysis of variance was performed to assess change across time (at issue, 6 months, and 12 months). Analyses were conducted using all available data (n = 43) and compliant data (n = 18). No significant difference was found in the reduction of mean peak pressure tested across time (P < .05). For both sites, significant differences in insole depth were identified between issue and 6 months and between issue and 12 months but not between 6 and 12 months (P < .05). Most insole compression occurred during the initial 6 months. Visual material compression does not seem to be a reliable indicator of insole usefulness. Frequency of insole replacement is best informed by a functional review of effect determined using an in-shoe pressure measurement system. These results suggest that insoles for diabetic neuropathic patients can be effective in maintaining peak pressure reduction for 12 months regardless of wear frequency.

Different Muscle-Recruitment Strategies Among Elite Breaststrokers.

PubMed

Guignard, Brice; Olstad, Bjørn H; Simbaña Escobar, David; Lauer, Jessy; Kjendlie, Per-Ludvik; Rouard, Annie H

2015-11-01

To investigate electromyographical (EMG) profiles characterizing the lower-limb flexion-extension in an aquatic environment in high-level breaststrokers. The 2-dimensional breaststroke kick of 1 international- and 2 national-level female swimmers was analyzed during 2 maximal 25-m swims. The activities of biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior were recorded. The breaststroke kick was divided in 3 phases, according to the movements performed in the sagittal plane: push phase (PP) covering 27% of the total kick duration, glide phase (GP) 41%, and recovery phase (RP) 32%. Intrasubject reproducibility of the EMG and kinematics was observed from 1 stroke cycle to another. In addition, important intersubject kinematic reproducibility was noted, whereas muscle activities discriminated the subjects: The explosive PP was characterized by important muscle-activation peaks. During the recovery, muscles were likewise solicited for swimmers 1 (S1) and 2 (S2), while the lowest activities were observed during GP for S2 and swimmer 3 (S3), but not for S1, who maintained major muscle solicitations. The main muscle activities were observed during PP to perform powerful lower-limb extension. The most-skilled swimmer (S1) was the only 1 to solicit her muscles during GP to actively reach better streamlining. Important activation peaks during RP correspond to the limbs acting against water drag. Such differences in EMG strategies among an elite group highlight the importance of considering the muscle parameters used to effectively control the intensity of activation among the phases for a more efficient breaststroke kick.

Biomechanical characteristics and speed adaptation during kick double poling on roller skis in elite cross-country skiers.

PubMed

Göpfert, Caroline; Holmberg, Hans-Christer; Stöggl, Thomas; Müller, Erich; Lindinger, Stefan Josef

2013-06-01

Recent developments in cross-country ski racing should promote the use of kick double poling. This technique, however, has not been the focus in athletes' training and has barely been investigated. The aims of the present study were to develop a function-based phase definition and to analyse speed adaptation mechanisms for kick double poling in elite cross-country skiers. Joint kinematics and pole/plantar forces were recorded in 10 athletes while performing kick double poling at three submaximal roller skiing speeds. A speed increase was associated with increases in cycle length and rate, while absolute poling and leg push-off durations shortened. Despite maintained impulses of force, the peak and average pole/leg forces increased. During double poling and leg push-off, ranges of motion of elbow flexion and extension increased (p < 0.05) and were maintained for hip/knee flexion and extension. Cycle length increase was correlated to increases in average poling force (r = 0.71) and arm swing time (r = 0.88; both p < 0.05). The main speed adaptation was achieved by changes in double poling technique; however, leg push-off showed high variability among elite skiers, thus illustrating important aspects for technique training.

Plasma Wall interaction in the IGNITOR machine

NASA Astrophysics Data System (ADS)

Ferro, C.

1998-11-01

One of the critical issues in ignited machines is the management of the heat and particle exhaust without degradation of the plasma quality (pollution and confinement time) and without damage of the material facing the plasma. The IGNITOR machine has been conceived as a ``limiter" device, i.e., with the plasma leaning nearly on the entire surface of the first wall. Peak heat loads can easily be maintained at values lower than 1.35 MW/m^2 even considering displacements of the plasma column^1. This ``limiter" choice is based on the operational performances of high density, high field machines which suggests that intrinsic physics processes in the edge of the plasma are effective in spreading heat loads and maintaining the plasma pollution at a low level. The possibility of these operating scenarios has been demonstrated recently by different machines both in limiter and divertor configurations. The basis for the different physical processes that are expected to influence the IGNITOR edge parameters ^2 are discussed and a comparison with the latest experimental results is given. ^1 C. Ferro, G. Franzoni, R. Zanino, ENEA Internal Report RT/ERG/FUS/94/14. ^2 C. Ferro, R. Zanino, J. Nucl. Mater. 543, 176 (1990).

Overview and Current Status of Analyses of Potential LEU Design Concepts for TREAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Connaway, H. M.; Kontogeorgakos, D. C.; Papadias, D. D.

2015-10-01

Neutronic and thermal-hydraulic analyses have been performed to evaluate the performance of different low-enriched uranium (LEU) fuel design concepts for the conversion of the Transient Reactor Test Facility (TREAT) from its current high-enriched uranium (HEU) fuel. TREAT is an experimental reactor developed to generate high neutron flux transients for the testing of nuclear fuels. The goal of this work was to identify an LEU design which can maintain the performance of the existing HEU core while continuing to operate safely. A wide variety of design options were considered, with a focus on minimizing peak fuel temperatures and optimizing the powermore » coupling between the TREAT core and test samples. Designs were also evaluated to ensure that they provide sufficient reactivity and shutdown margin for each control rod bank. Analyses were performed using the core loading and experiment configuration of historic M8 Power Calibration experiments (M8CAL). The Monte Carlo code MCNP was utilized for steady-state analyses, and transient calculations were performed with the point kinetics code TREKIN. Thermal analyses were performed with the COMSOL multi-physics code. Using the results of this study, a new LEU Baseline design concept is being established, which will be evaluated in detail in a future report.« less

Density impact on performance of composite Si/graphite electrodes

DOE PAGES

Dufek, Eric J.; Picker, Michael; Petkovic, Lucia M.

2016-01-27

The ability of alkali-substituted binders for composite Si and graphite negative electrodes to minimize capacity fade for lithium ion batteries is investigated. Polymer films and electrodes are described and characterized by FTIR following immersion in electrolyte (1:2 EC:DMC) for 24 h. FTIR analysis following electrode formation displayed similar alkali-ion dependent shifts in peak location suggesting that changes in the vibrational structure of the binder are maintained after electrode formation. The Si and graphite composite electrodes prepared using the alkali-substituted polyacrylates were also exposed to electrochemical cycling and it has been found that the performance of the Na-substituted binder is superiormore » to a comparable density K-substituted system. However, in comparing performance across many different electrode densities attention needs to be placed on making comparisons at similar densities, as low density electrodes tend to exhibit lower capacity fade over cycling. This is highlighted by a 6% difference between a low density K-substituted electrode and a high density Na-substituted sample. As a result, this low variance between the two systems makes it difficult to quickly make a direct evaluation of binder performance unless electrode density is tightly controlled.« less

Design and Follow-on from 50 kJ Fusion Yield using High-Density Carbon Capsules at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Berzak Hopkins, L.; Lepape, S.; Divol, L.; Pak, A.; Goyon, C.; Dewald, E.; Ho, D. D.; Khan, S. F.; Weber, C.; Meezan, N. B.; Biener, J.; Grim, G.; Ma, T.; Milovich, J. L.; Moore, A. S.; Nikroo, A.; Ross, J. S.; Stadermann, M.; Volegov, P.; Wild, C.; Callahan, D. A.; Hurricane, O. A.; Hsing, W. W.; Town, R. P. J.; Edwards, M. J.

2017-10-01

We have demonstrated nearly 3x alpha-heating at the National Ignition Facility by using tungsten-doped High-Density Carbon (HDC) capsules in low gasfill, unlined, uranium (DU) hohlraums. Shot N170601 achieved a primary neutron yield of 1.5 x 1016 neutrons with a Deuterium-Tritium ion temperature of 4.7 keV. Predecessor experiments demonstrated high-performing, efficient performance, as noted through high neutron yield production per laser energy input. Building on these `subscale' results, follow-on experiments utilize an 8% larger target than the predecessor campaign, to increase the capsule surface area and absorbed energy. The capsule fill tube has been reduced in size from 10 to 5 micron diameter, and the laser design implements a new, ``drooping'' technique for the end of the pulse, to reduce the time between laser shut-off and capsule peak emission while still maintaining capsule mass remaining. Design of the current platform as well as avenues to potentially improve performance based on these experiments will be discussed. Work performed under the auspices of the U.S. D.O.E. by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

Automatic peak selection by a Benjamini-Hochberg-based algorithm.

PubMed

Abbas, Ahmed; Kong, Xin-Bing; Liu, Zhi; Jing, Bing-Yi; Gao, Xin

2013-01-01

A common issue in bioinformatics is that computational methods often generate a large number of predictions sorted according to certain confidence scores. A key problem is then determining how many predictions must be selected to include most of the true predictions while maintaining reasonably high precision. In nuclear magnetic resonance (NMR)-based protein structure determination, for instance, computational peak picking methods are becoming more and more common, although expert-knowledge remains the method of choice to determine how many peaks among thousands of candidate peaks should be taken into consideration to capture the true peaks. Here, we propose a Benjamini-Hochberg (B-H)-based approach that automatically selects the number of peaks. We formulate the peak selection problem as a multiple testing problem. Given a candidate peak list sorted by either volumes or intensities, we first convert the peaks into [Formula: see text]-values and then apply the B-H-based algorithm to automatically select the number of peaks. The proposed approach is tested on the state-of-the-art peak picking methods, including WaVPeak [1] and PICKY [2]. Compared with the traditional fixed number-based approach, our approach returns significantly more true peaks. For instance, by combining WaVPeak or PICKY with the proposed method, the missing peak rates are on average reduced by 20% and 26%, respectively, in a benchmark set of 32 spectra extracted from eight proteins. The consensus of the B-H-selected peaks from both WaVPeak and PICKY achieves 88% recall and 83% precision, which significantly outperforms each individual method and the consensus method without using the B-H algorithm. The proposed method can be used as a standard procedure for any peak picking method and straightforwardly applied to some other prediction selection problems in bioinformatics. The source code, documentation and example data of the proposed method is available at http://sfb.kaust.edu.sa/pages/software.aspx.

Automatic Peak Selection by a Benjamini-Hochberg-Based Algorithm

PubMed Central

Abbas, Ahmed; Kong, Xin-Bing; Liu, Zhi; Jing, Bing-Yi; Gao, Xin

2013-01-01

A common issue in bioinformatics is that computational methods often generate a large number of predictions sorted according to certain confidence scores. A key problem is then determining how many predictions must be selected to include most of the true predictions while maintaining reasonably high precision. In nuclear magnetic resonance (NMR)-based protein structure determination, for instance, computational peak picking methods are becoming more and more common, although expert-knowledge remains the method of choice to determine how many peaks among thousands of candidate peaks should be taken into consideration to capture the true peaks. Here, we propose a Benjamini-Hochberg (B-H)-based approach that automatically selects the number of peaks. We formulate the peak selection problem as a multiple testing problem. Given a candidate peak list sorted by either volumes or intensities, we first convert the peaks into -values and then apply the B-H-based algorithm to automatically select the number of peaks. The proposed approach is tested on the state-of-the-art peak picking methods, including WaVPeak [1] and PICKY [2]. Compared with the traditional fixed number-based approach, our approach returns significantly more true peaks. For instance, by combining WaVPeak or PICKY with the proposed method, the missing peak rates are on average reduced by 20% and 26%, respectively, in a benchmark set of 32 spectra extracted from eight proteins. The consensus of the B-H-selected peaks from both WaVPeak and PICKY achieves 88% recall and 83% precision, which significantly outperforms each individual method and the consensus method without using the B-H algorithm. The proposed method can be used as a standard procedure for any peak picking method and straightforwardly applied to some other prediction selection problems in bioinformatics. The source code, documentation and example data of the proposed method is available at http://sfb.kaust.edu.sa/pages/software.aspx. PMID:23308147

40 CFR 63.11441 - What are the notification requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Clay Ceramics Manufacturing Area... glazed ceramic ware, you must certify that you are maintaining the peak temperature below 1540 °C (2800... ceramics manufacturing facility that uses more than 227 Mg/yr (250 tpy) of wet glaze(s), you must certify...

Improving UV Resistance of High Performance Fibers

NASA Astrophysics Data System (ADS)

Hassanin, Ahmed

High performance fibers are characterized by their superior properties compared to the traditional textile fibers. High strength fibers have high modules, high strength to weight ratio, high chemical resistance, and usually high temperature resistance. It is used in application where superior properties are needed such as bulletproof vests, ropes and cables, cut resistant products, load tendons for giant scientific balloons, fishing rods, tennis racket strings, parachute cords, adhesives and sealants, protective apparel and tire cords. Unfortunately, Ultraviolet (UV) radiation causes serious degradation to the most of high performance fibers. UV lights, either natural or artificial, cause organic compounds to decompose and degrade, because the energy of the photons of UV light is high enough to break chemical bonds causing chain scission. This work is aiming at achieving maximum protection of high performance fibers using sheathing approaches. The sheaths proposed are of lightweight to maintain the advantage of the high performance fiber that is the high strength to weight ratio. This study involves developing three different types of sheathing. The product of interest that need be protected from UV is braid from PBO. First approach is extruding a sheath from Low Density Polyethylene (LDPE) loaded with different rutile TiO2 % nanoparticles around the braid from the PBO. The results of this approach showed that LDPE sheath loaded with 10% TiO2 by weight achieved the highest protection compare to 0% and 5% TiO2. The protection here is judged by strength loss of PBO. This trend noticed in different weathering environments, where the sheathed samples were exposed to UV-VIS radiations in different weatheromter equipments as well as exposure to high altitude environment using NASA BRDL balloon. The second approach is focusing in developing a protective porous membrane from polyurethane loaded with rutile TiO2 nanoparticles. Membrane from polyurethane loaded with 4% rutile TiO2 nanoparticles showed excellent protection of braid from PBO. Only 7.5% strength loss was observed. To optimize the degree of protection of the sheath loaded with UV blocker particles, computational models were developed to optimize the protective layer thickness/weight and the amount of UV particles that provide the maximum protection with lightest weight of the protective layer and minimum amount of UV particles. The simulated results were found to be higher that the experimental results due to the tendency of nanoparticles to be agglomerated in real experiments. The third approach to achieve a maximum protection with the minimum weight added is constructing a sleeve from SpectraRTM (Ultra High Molecular Weight Polyethylene (UHMWPE) high performance fiber), which is known to resist UV, woven fabric. Covering the braid from PBO fiber with Spectra RTM woven fabric provide hybrid structure with two compatible components that can share the load and thus maintain the high strength to weight ratio. Although the SpectraRTM fabric had maximum cover factor, 20 % of visible light and about 15 % of UV were able to penetrate the fabric. This transmittance of UV-VIS light negatively affected the protection performance of the SpectraRTM woven fabric layer. It is thought that SpectraRTM fabric be coated with a thin layer (mentioned earlier) containing UV blocker for additional protection while maintain strength contribution to the hybrid structure. To maximize the strength to weight ratio of the hybrid structure (with core from PBO braid and sheath from SpectraRTM woven fabric) an established finite element model was utilized. The theoretical results using the finite element theory indicated that by controlling the bending rigidity of the filling yarn of the SpectraRTM fabric, the extension at peak load of woven fabric in warp direction (loading direction) could be controlled to match the braid extension at peak load. The match in the extension at peak load of the two components of the hybrid structure allowed the maximum strength to weight ratio. Thus, the SpectraRTM woven layer could achieve both the protection from UV and the load share in the hybrid structure.

Does team lifting increase the variability in peak lumbar compression in ironworkers?

PubMed

Faber, Gert; Visser, Steven; van der Molen, Henk F; Kuijer, P Paul F M; Hoozemans, Marco J M; Van Dieën, Jaap H; Frings-Dresen, Monique H W

2012-01-01

Ironworkers frequently perform heavy lifting tasks in teams of two or four workers. Team lifting could potentially lead to a higher variation in peak lumbar compression forces than lifts performed by one worker, resulting in higher maximal peak lumbar compression forces. This study compared single-worker lifts (25-kg, iron bar) to two-worker lifts (50-kg, two iron bars) and to four-worker lifts (100-kg, iron lattice). Inverse dynamics was used to calculate peak lumbar compression forces. To assess the variability in peak lumbar loading, all three lifting tasks were performed six times. Results showed that the variability in peak lumbar loading was somewhat higher in the team lifts compared to the single-worker lifts. However, despite this increased variability, team lifts did not result in larger maximum peak lumbar compression forces. Therefore, it was concluded that, from a biomechanical point of view, team lifting does not result in an additional risk for low back complaints in ironworkers.

Acute Effects of the Elevation Training Mask on Strength Performance in Recreational Weight lifters.

PubMed

Jagim, Andrew R; Dominy, Trevor A; Camic, Clayton L; Wright, Glenn; Doberstein, Scott; Jones, Margaret T; Oliver, Jonathan M

2018-02-01

Jagim, AR, Dominy, TA, Camic, CL, Wright, G, Doberstein, S, Jones, MT, and Oliver, JM. Acute effects of the elevation training mask on strength performance in recreational weightlifters. J Strength Cond Res 32(2): 482-489, 2018-The Elevation Training Mask 2.0 (ETM) is a novel device that purportedly simulates altitude training. The purpose of this study was to investigate the acute effects of the ETM on resistance exercise performance, metabolic stress markers, and ratings of mental fatigue. Twenty male recreational weight lifters completed 2 training sessions of back squat and bench press (6 sets of 10 repetitions at 85% of 5-repetition maximum and seventh set to failure) as well as a maximal effort sprint test (18% body mass) with the mask (ETM) and without the mask (NM). Training evaluation included baseline and postexercise blood lactate and oxygen saturation measures. Performance evaluation included peak and average velocity bar velocity, total volume load, total work, total repetitions completed, and sprint performance. Adverse side effects were reported in 12% (n = 3) of participants, which included feelings of light headedness, anxiety, and discomfort. No differences were found in repetitions or total workload in back squat (p = 0.07) or bench press (p = 0.08) between conditions. A lower peak velocity was identified during the back squat, bench press, and sprint test in the ETM condition (p = 0.04). Blood lactate values were lower after bench press and sprint during the ETM condition (p < 0.001). Significantly lower ratings of alertness and focus for task were found after squat, bench press, and sprint test in the ETM condition compared with the NM condition (p < 0.001). Wearing the ETM during bouts of resistance training did not hinder the ability to achieve desired training volumes during the resistance training session. However, wearing the ETM does seem to attenuate the ability to maintain working velocity during training bouts and negatively influence ratings of alertness and focus for task.

Interaction of dipalmitoyl phosphatidylcholine (DPPC) liposomes and insulin

NASA Astrophysics Data System (ADS)

Mady, Mohsen M.; Elshemey, Wael M.

2011-06-01

Insulin, a peptide that has been used for decades in the treatment of diabetes, has well-defined properties and delivery requirements. Liposomes, which are lipid bilayer vesicles, have gained increasing attention as drug carriers which reduce the toxicity and increase the pharmacological activity of various drugs. The molecular interaction between (uncharged lipid) dipalmitoyl phosphatidylcholine (DPPC) liposomes and insulin has been characterized by using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. The characteristic protein absorption band peaks, Amide I (at about 1660 cm-1) and Amide II band (at about 1546 cm-1) are potentially reduced in the liposome insulin complex. Wide-angle x-ray scattering measurements showed that the association of insulin with DPPC lipid of liposomes still maintains the characteristic DPPC diffraction peaks with almost no change in relative intensities or change in peak positions. The absence of any shift in protein peak positions after insulin being associated with DPPC liposomes indicates that insulin is successfully forming complex with DPPC liposomes with possibly no pronounced alterations in the structure of insulin molecule.

Wavelength-agile high-power sources via four-wave mixing in higher-order fiber modes.

PubMed

Demas, J; Prabhakar, G; He, T; Ramachandran, S

2017-04-03

Frequency doubling of conventional fiber lasers in the near-infrared remains the most promising method for generating integrated high-peak-power lasers in the visible, while maintaining the benefits of a fiber geometry; but since the shortest wavelength power-scalable fiber laser sources are currently restricted to either the 10XX nm or 15XX nm wavelength ranges, accessing colors other than green or red remains a challenge with this schematic. Four-wave mixing using higher-order fiber modes allows for control of dispersion while maintaining large effective areas, thus enabling a power-scalable method to extend the bandwidth of near-infrared fiber lasers, and in turn, the bandwidth of potential high-power sources in the visible. Here, two parametric sources using the LP_0,7 and LP_0,6 modes of two step-index multi-mode fibers are presented. The output wavelengths for the sources are 880, 974, 1173, and 1347 nm with peak powers of 10.0, 16.2, 14.7, and 6.4 kW respectively, and ~300-ps pulse durations. The efficiencies of the sources are analyzed, along with a discussion of wavelength tuning and further power scaling, representing an advance in increasing the bandwidth of near-infrared lasers as a step towards high-peak-power sources at wavelengths across the visible spectrum.

The performances of standard and ResMed masks during bag-valve-mask ventilation.

PubMed

Lee, Hyoung Youn; Jeung, Kyung Woon; Lee, Byung Kook; Lee, Seung Joon; Jung, Yong Hun; Lee, Geo Sung; Min, Yong Il; Heo, Tag

2013-01-01

A tight mask seal is frequently difficult to obtain and maintain during single-rescuer bag-valve-mask (BVM) ventilation. The ResMed mask (Bella Vista, NSW, Australia) is a continuous-positive-airway-pressure mask (CM) designed for noninvasive ventilation. In this study, we compared the ventilation performances of a standard mask (SM) and a ResMed CM using a simulation manikin in an out-of-hospital single-rescuer BVM ventilation scenario. Thirty emergency medical technicians (EMTs) performed two 2-minute attempts to ventilate a simulation manikin using BVM ventilation, alternatively, with the SM or the ResMed CM in a randomized order. Ventilation parameters including tidal volume and peak airway pressure were measured using computer analysis software connected to the simulation manikin. Successful volume delivery was defined as delivery of 440-540 mL of tidal volume in accord with present cardiopulmonary resuscitation guidelines. BVM ventilation using the ResMed CM produced higher mean (± standard deviation) tidal volumes (452 ± 50 mL vs. 394 ± 113 mL, p = 0.014) and had a higher proportion of successful volume deliveries (65.3% vs. 26.7%, p < 0.001) than that using the SM. Peak airway pressure was higher in BVM ventilation using the ResMed CM (p = 0.035). Stomach insufflation did not occur during either method. Twenty-nine of the participants (96.7%) preferred BVM ventilation using the ResMed CM. BVM ventilations using ResMed CM resulted in a significantly higher proportion of successful volume deliveries meeting the currently recommended range of tidal volume. Clinical studies are needed to determine the value of the ResMed CM for BVM ventilation.

High Intensity Interval Training in Handcycling: The Effects of a 7 Week Training Intervention in Able-bodied Men

PubMed Central

Schoenmakers, Patrick; Reed, Kate; Van Der Woude, Luc; Hettinga, Florentina J.

2016-01-01

Introduction: In lower body endurance training, quantities of both moderate intensity continuous training (MICT) and high intensity interval training (HIIT) can lead to an improved physiological capacity and performance. Limited research is available regarding the endurance and muscular capacity of the upper body, and how training contributes to improvements in performance capacity is still unknown. The aim of the current study was to evaluate the effects of HIIT and MICT on the physiological capacity and handcycling performance of able-bodied men in a well-controlled laboratory setting. Methods: Twenty four recreationally active men (22 ± 2 years; 1.84 ± 0.04 m; 79 ± 10 kg) were matched on incremental handcycling pre-test performance (peakPO) and then randomly assigned to HIIT, MICT, or a non-training control group (CON, 3 × n = 8). Participants in HIIT completed 14 interval training sessions, performing 4 × 4 min intervals at 85% heart rate reserve (%HRR), and seven continuous training sessions at 55 %HRR (every 2nd training session of the week). Participants in MICT performed 21 training sessions of 30 min at 55 %HRR. After the intervention, changes in peak oxygen uptake (peakVO2) and peak power output (peakPO) were compared within and between HIIT, MICT and CON. Results: The average external training load per training session did not differ between MICT and HIIT (p = 0.713). Improvements after HIIT in peakVO2 (22.2 ± 8.1%) and peakPO (47.1 ± 20.7%) were significantly larger compared with MICT and CON (p < 0.001). Improvements after MICT in peakVO2 (10.7 ± 12.9%) and peakPO (32.2 ± 8.1%) were higher compared to CON (p < 0.001). Higher improvement after HIIT occurred despite training 22% less time than MICT. No significant changes were found in CON. Discussion: As in lower body endurance sports, HIIT proved to be very effective in improving the physiological and performance capacity of upper body exercise. Whilst physiological capacity in both training groups improved significantly compared with CON, the present study shows that peakVO2 and peakPO improved more after HIIT than after MICT in able-bodied men. It is advised to include HIIT into training regimes of recreational and competitive handcyclists to improve the upper body endurance capacity. PMID:28066268

High Intensity Interval Training in Handcycling: The Effects of a 7 Week Training Intervention in Able-bodied Men.

PubMed

Schoenmakers, Patrick; Reed, Kate; Van Der Woude, Luc; Hettinga, Florentina J

2016-01-01

Introduction: In lower body endurance training, quantities of both moderate intensity continuous training (MICT) and high intensity interval training (HIIT) can lead to an improved physiological capacity and performance. Limited research is available regarding the endurance and muscular capacity of the upper body, and how training contributes to improvements in performance capacity is still unknown. The aim of the current study was to evaluate the effects of HIIT and MICT on the physiological capacity and handcycling performance of able-bodied men in a well-controlled laboratory setting. Methods: Twenty four recreationally active men (22 ± 2 years; 1.84 ± 0.04 m; 79 ± 10 kg) were matched on incremental handcycling pre-test performance (peakPO) and then randomly assigned to HIIT, MICT, or a non-training control group (CON, 3 × n = 8). Participants in HIIT completed 14 interval training sessions, performing 4 × 4 min intervals at 85% heart rate reserve (%HRR), and seven continuous training sessions at 55 %HRR (every 2nd training session of the week). Participants in MICT performed 21 training sessions of 30 min at 55 %HRR. After the intervention, changes in peak oxygen uptake (peakVO 2 ) and peak power output (peakPO) were compared within and between HIIT, MICT and CON. Results: The average external training load per training session did not differ between MICT and HIIT ( p = 0.713). Improvements after HIIT in peakVO 2 (22.2 ± 8.1%) and peakPO (47.1 ± 20.7%) were significantly larger compared with MICT and CON ( p < 0.001). Improvements after MICT in peakVO 2 (10.7 ± 12.9%) and peakPO (32.2 ± 8.1%) were higher compared to CON ( p < 0.001). Higher improvement after HIIT occurred despite training 22% less time than MICT. No significant changes were found in CON. Discussion: As in lower body endurance sports, HIIT proved to be very effective in improving the physiological and performance capacity of upper body exercise. Whilst physiological capacity in both training groups improved significantly compared with CON, the present study shows that peakVO 2 and peakPO improved more after HIIT than after MICT in able-bodied men. It is advised to include HIIT into training regimes of recreational and competitive handcyclists to improve the upper body endurance capacity.

Every-other-day Dosing of Oral Viscous Budesonide Is not Effective in the Management of Eosinophlic Esophagitis.

PubMed

Rubinstein, Eitan; Hait, Elizabeth E; Mitchell, Paul D; Lee, John J

2018-03-01

Eosinophilic esophagitis (EoE) is a clinicopathologic disorder characterized histologically by esophageal eosinophilia. Oral viscous budesonide (OVB) is an effective treatment with remission rates reported between 55% and 87%; however, topical corticosteroids are associated with increased risk of candidal esophagitis and adrenal suppression. Attempts to decrease the daily dose of topical steroids have resulted in disease relapse. The objective of this study was to determine whether or not reducing the frequency of OVB administration would be effective in controlling esophageal eosinophilia in children and adolescents. Data were obtained by retrospective chart review of patients at Boston Children's Hospital diagnosed with EoE, based on endoscopic findings of >15 eosinophils per high power field (eos/HPF) on esophageal biopsies while on acid blockade. Patients with histologic evidence of response (<15 eos/HPF) while on daily OVB had been offered the option of maintenance therapy based on a Monday-Wednesday-Friday (MWF) dosing regimen. Changes in peak esophageal eosinophil counts over time were examined. Eight male patients ages 5 to 18 years attained clinical response while receiving daily OVB and were subsequently maintained on a MWF OVB dosing regimen for 3 to 7 months. All 8 patients showed an increase in peak esophageal eosinophils, with 7 of 8 (88%) experiencing disease relapse. In fact, the distribution of peak esophageal eosinophils after MWF dosing was not statistically different from peak levels at diagnosis (P = 0.95). An MWF dosing regimen of OVB was not effective at maintaining histologic response in children and adolescents with EoE. Larger prospective studies are warranted to confirm these results.

Cost-effective retrofit technology for reducing peak power demand in small and medium commercial buildings

DOE PAGES

Nutaro, James J.; Fugate, David L.; Kuruganti, Teja; ...

2015-05-27

We describe a cost-effective retrofit technology that uses collective control of multiple rooftop air conditioning units to reduce the peak power consumption of small and medium commercial buildings. The proposed control uses a model of the building and air conditioning units to select an operating schedule for the air conditioning units that maintains a temperature set point subject to a constraint on the number of units that may operate simultaneously. A prototype of this new control system was built and deployed in a large gymnasium to coordinate four rooftop air conditioning units. Based on data collected while operating this prototype,more » we estimate that the cost savings achieved by reducing peak power consumption is sufficient to repay the cost of the prototype within a year.« less

Electrochemical Properties of Poly(Anthraquinonyl Sulfide)/Graphene Sheets Composites as Electrode Materials for Electrochemical Capacitors

PubMed Central

Lee, Wonkyun; Suzuki, Shinya; Miyayama, Masaru

2014-01-01

Poly(anthraquinonyl sulfide) (PAQS)/graphene sheets (GSs) composite was synthesized through in situ polymerization to evaluate its performance as an electrode material for electrochemical capacitors. PAQS was successfully synthesized in the presence of GSs with uniform distribution. PAQS/GSs showed a pair of reversible redox peaks at around 0 V (vs. Ag/AgCl). The specific capacitance of PAQS/GSs was 349 F·g−1 (86 mAh·g−1) at a current density of 500 mA·g−1, and a capacitance of 305 F·g−1 was maintained even at a high current density of 5000 mA·g−1. The in situ polymerization of PAQS with GSs facilitated their interaction and enabled faster charge transfer and redox reaction, resulting in enhanced electrode properties. PMID:28344238

Human albumin solders for clinical application during laser tissue welding.

PubMed

Poppas, D P; Wright, E J; Guthrie, P D; Shlahet, L T; Retik, A B

1996-01-01

Fifty percent human albumin solder significantly improves weld strength when compared to lower concentrations [Wright et al., ASLMS meeting, April, 1995]. We developed a method for preparing 50% human albumin that may be considered compatible for clinical applications. Fifty percent human albumin solder was prepared from 25% commercially available human albumin using a lyophilization technique. Assessment of sterility, viscosity, pH, and peak absorption wavelength were performed. This report describes the methodology used to prepare a 50% human albumin solder that is compatible with clinical use. Maintenance of the structural integrity of the albumin was confirmed by polyacrylamide gel electrophoresis. This solder preparation can be used alone or with the addition of exogenous chromophores. The final product is sterile, incorporates viral free protocols, maintains high viscosity, and can be applied easily during open or laparoscopic procedures.

Exercise Within LBNP to Produce Artificial Gravity

NASA Technical Reports Server (NTRS)

Hargens, Alan R.

1996-01-01

Integrated physiologic countermeasures are needed to maintain orthostatic tolerance after spaceflight or bed rest. We hypothesized that supine exercise during LBNP would prevent bed rest-induced loss of orthostatic tolerance by preventing hemoconcentration. In a study conducted jointly with NASA Johnson Space Center and the University of Texas Medical Branch, Galveston, TX, fifteen male subjects underwent 5 days of 6 deg head-down bed rest: 5 control subjects did not exercise, and 10 performed 30 min/day of supine interval treadmill exercise at intensities up to 90% VO(sub 2peak). We will undertake two 14 day bed-rest studies (6 deg head-down tilt bed rest, HDT) to investigate the mechanism of action and efficacy of our partial vacuum exerciser concept. These 14 day bed rest studies were chosen to simulate current microgravity exposures for Space Shuttle crew members.

High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography*

PubMed Central

Desmarais, Samantha M.; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D.; de Pedro, Miguel A.; Huang, Kerwyn Casey

2015-01-01

The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination. PMID:26468288

A simple multi-scale Gaussian smoothing-based strategy for automatic chromatographic peak extraction.

PubMed

Fu, Hai-Yan; Guo, Jun-Wei; Yu, Yong-Jie; Li, He-Dong; Cui, Hua-Peng; Liu, Ping-Ping; Wang, Bing; Wang, Sheng; Lu, Peng

2016-06-24

Peak detection is a critical step in chromatographic data analysis. In the present work, we developed a multi-scale Gaussian smoothing-based strategy for accurate peak extraction. The strategy consisted of three stages: background drift correction, peak detection, and peak filtration. Background drift correction was implemented using a moving window strategy. The new peak detection method is a variant of the system used by the well-known MassSpecWavelet, i.e., chromatographic peaks are found at local maximum values under various smoothing window scales. Therefore, peaks can be detected through the ridge lines of maximum values under these window scales, and signals that are monotonously increased/decreased around the peak position could be treated as part of the peak. Instrumental noise was estimated after peak elimination, and a peak filtration strategy was performed to remove peaks with signal-to-noise ratios smaller than 3. The performance of our method was evaluated using two complex datasets. These datasets include essential oil samples for quality control obtained from gas chromatography and tobacco plant samples for metabolic profiling analysis obtained from gas chromatography coupled with mass spectrometry. Results confirmed the reasonability of the developed method. Copyright © 2016 Elsevier B.V. All rights reserved.

19 CFR 143.6 - Failure to maintain performance standards.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Failure to maintain performance standards. 143.6... maintain performance standards. ABI participants must adhere to the performance requirements and... maximum of 90 days, if the participant's performance remains below standard, but, except for immediate...

Exercise training-induced different improvement profile of endothelial progenitor cells function in mice with or without myocardial infarction.

PubMed

Guo, Yuan; Peng, Ran; Liu, Qiong; Xu, Danyan

2016-10-15

Neovascularization in response to ischemia after myocardial infarction (MI) has been widely considered as being initiated by endothelial progenitor cells (EPCs). Well-documented evidences in recent years have proved exercise training (ET) improving EPC function. However, whether ET-induced improvement of EPC function under or without ischemic state is different has not been reported. Mice performed ET following an exercise prescription 1week after MI or non-MI surgery respectively. Bone marrow-derived EPCs were isolated at 0day, 3days, 1week, 2weeks, 4weeks, and 8weeks of ET. After 7days cultivation, EPC functions including proliferation, adhesion, migration, and in vitro angiogenesis were measured. AKT/glycogen synthase kinase 3β (GSK3β) signaling pathway was tested by western blotting. EPC function in mice underwent non-MI surgery was attenuated overtime, while ET ameliorated this tendency. EPC function was peaked at 4weeks ET in non-MI surgery mice and maintained with an extended exercise time. Besides, simple ischemia was sufficient to enhanced EPC function, with a maximum at 2weeks of MI surgery. In MI mice, ET further improved EPC function and achieved peak at 2weeks exercise. Furthermore, AKT/GSK3β signaling pathway activation was consistent with EPC function change after ischemia, which was further promoted by 4weeks exercise. ET significantly increased EPC function in mice both with and without MI, but the time points of peak function were different. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Neuroimaging markers associated with maintenance of optimal memory performance in late-life.

PubMed

Dekhtyar, Maria; Papp, Kathryn V; Buckley, Rachel; Jacobs, Heidi I L; Schultz, Aaron P; Johnson, Keith A; Sperling, Reisa A; Rentz, Dorene M

2017-06-01

Age-related memory decline has been well-documented; however, some individuals reach their 8th-10th decade while maintaining strong memory performance. To determine which demographic and biomarker factors differentiated top memory performers (aged 75+, top 20% for memory) from their peers and whether top memory performance was maintained over 3 years. Clinically normal adults (n=125, CDR=0; age: 79.5±3.57 years) from the Harvard Aging Brain Study underwent cognitive testing and neuroimaging (amyloid PET, MRI) at baseline and 3-year follow-up. Participants were grouped into Optimal (n=25) vs. Typical (n=100) performers using performance on 3 challenging memory measures. Non-parametric tests were used to compare groups. There were no differences in age, sex, or education between Optimal vs. Typical performers. The Optimal group performed better in Processing Speed (p=0.016) and Executive Functioning (p<0.001). Optimal performers had larger hippocampal volumes at baseline compared with Typical Performers (p=0.027) but no differences in amyloid burden (p=0.442). Twenty-three of the 25 Optimal performers had longitudinal data and16 maintained top memory performance while 7 declined. Non-Maintainers additionally declined in Executive Functioning but not Processing Speed. Longitudinally, there were no hippocampal volume differences between Maintainers and Non-Maintainers, however Non-Maintainers exhibited higher amyloid burden at baseline in contrast with Maintainers (p=0.008). Excellent memory performance in late life does not guarantee protection against cognitive decline. Those who maintain an optimal memory into the 8th and 9th decades may have lower levels of AD pathology. Copyright © 2017. Published by Elsevier Ltd.

Loading of Hip Measured by Hip Contact Forces at Different Speeds of Walking and Running.

PubMed

Giarmatzis, Georgios; Jonkers, Ilse; Wesseling, Mariska; Van Rossom, Sam; Verschueren, Sabine

2015-08-01

Exercise plays a pivotal role in maximizing peak bone mass in adulthood and maintaining it through aging, by imposing mechanical loading on the bone that can trigger bone mineralization and growth. The optimal type and intensity of exercise that best enhances bone strength remains, however, poorly characterized, partly because the exact peak loading of the bone produced by the diverse types of exercises is not known. By means of integrated motion capture as an input to dynamic simulations, contact forces acting on the hip of 20 young healthy adults were calculated during walking and running at different speeds. During walking, hip contact forces (HCFs) have a two-peak profile whereby the first peak increases from 4.22 body weight (BW) to 5.41 BW and the second from 4.37 BW to 5.74 BW, by increasing speed from 3 to 6 km/h. During running, there is only one peak HCF that increases from 7.49 BW to 10.01 BW, by increasing speed from 6 to 12 km/h. Speed related profiles of peak HCFs and ground reaction forces (GRFs) reveal a different progression of the two peaks during walking. Speed has a stronger impact on peak HCFs rather than on peak GRFs during walking and running, suggesting an increasing influence of muscle activity on peak HCF with increased speed. Moreover, results show that the first peak of HCF during walking can be predicted best by hip adduction moment, and the second peak of HCF by hip extension moment. During running, peak HCF can be best predicted by hip adduction moment. The present study contributes hereby to a better understanding of musculoskeletal loading during walking and running in a wide range of speeds, offering valuable information to clinicians and scientists exploring bone loading as a possible nonpharmacological osteogenic stimulus. © 2015 American Society for Bone and Mineral Research. © 2015 American Society for Bone and Mineral Research.

Development of a Computer-Based Visualised Quantitative Learning System for Playing Violin Vibrato

ERIC Educational Resources Information Center

Ho, Tracy Kwei-Liang; Lin, Huann-shyang; Chen, Ching-Kong; Tsai, Jih-Long

2015-01-01

Traditional methods of teaching music are largely subjective, with the lack of objectivity being particularly challenging for violin students learning vibrato because of the existence of conflicting theories. By using a computer-based analysis method, this study found that maintaining temporal coincidence between the intensity peak and the target…

40 CFR 265.272 - General operating requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... preventing flow onto the active portions of the facility during peak discharge from at least a 25-year storm... capable of collecting and controlling a water volume at least equivalent to a 24-hour, 25-year storm. (d... must be emptied or otherwise managed expeditiously after storms to maintain design capacity of the...

40 CFR 265.272 - General operating requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... preventing flow onto the active portions of the facility during peak discharge from at least a 25-year storm... capable of collecting and controlling a water volume at least equivalent to a 24-hour, 25-year storm. (d... must be emptied or otherwise managed expeditiously after storms to maintain design capacity of the...

40 CFR 265.272 - General operating requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... preventing flow onto the active portions of the facility during peak discharge from at least a 25-year storm... capable of collecting and controlling a water volume at least equivalent to a 24-hour, 25-year storm. (d... must be emptied or otherwise managed expeditiously after storms to maintain design capacity of the...

40 CFR 265.272 - General operating requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... preventing flow onto the active portions of the facility during peak discharge from at least a 25-year storm... capable of collecting and controlling a water volume at least equivalent to a 24-hour, 25-year storm. (d... must be emptied or otherwise managed expeditiously after storms to maintain design capacity of the...

Soldering iron temperature is automatically reduced

NASA Technical Reports Server (NTRS)

Lum, J. Y.

1966-01-01

Hinged cradle-microswitch arrangement maintains a soldering iron at less than peak temperature when not in use. The microswitch introduces a voltage reducing element into the soldering iron power circuit when the iron is placed on the cradle. The iron, when removed from the cradle, returns to operating temperature in 15 to 30 seconds.

Responses of Six-Weeks Aquatic Exercise on the Autonomic Nervous System, Peak Nasal Inspiratory Flow and Lung Functions in Young Adults with Allergic Rhinitis.

PubMed

Janyacharoen, Taweesak; Kunbootsri, Narupon; Arayawichanon, Preeda; Chainansamit, Seksun; Sawanyawisuth, Kittisak

2015-06-01

Allergic rhinitis is a chronic respiratory disease. Sympathetic hypofunction is identified in all of the allergic rhinitis patients. Moreover, allergic rhinitis is associated with decreased peak nasal inspiratory flow (PNIF) and impaired lung functions. The aim of this study was to investigate effects of six-week of aquatic exercise on the autonomic nervous system function, PNIF and lung functions in allergic rhinitis patients. Twenty-six allergic rhinitis patients, 12 males and 14 females were recruited in this study. Subjects were diagnosed by a physician based on history, physical examination, and positive reaction to a skin prick test. Subjects were randomly assigned to two groups. The control allergic rhinitis group received education and maintained normal life. The aquatic group performed aquatic exercise for 30 minutes a day, three days a week for six weeks. Heart rate variability, PNIF and lung functions were measured at the beginning, after three weeks and six weeks. There were statistically significant increased low frequency normal units (LF n.u.), PNIF and showed decreased high frequency normal units (HF n.u.) at six weeks after aquatic exercise compared with the control group. Six weeks of aquatic exercise could increase sympathetic activity and PNIF in allergic rhinitis patients.

Techno-economic performance evaluation of solar tower plants with integrated multi-layered PCM thermocline thermal energy storage - A comparative study to conventional two-tank storage systems

NASA Astrophysics Data System (ADS)

Guedéz, Rafael; Ferruzza, Davide; Arnaudo, Monica; Rodríguez, Ivette; Perez-Segarra, Carlos D.; Hassar, Zhor; Laumert, Björn

2016-05-01

Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher investment costs and difficulties during the operation of the variable volume tanks. Instead, another solution can be a single tank thermocline storage in a multi-layered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost up to 30% and maintain high efficiencies. This paper analyses a multi-layered solid PCM storage tank concept for solar tower applications, and describes a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. A detail model of the tank has been developed and introduced in an existing techno-economic tool developed by the authors (DYESOPT). The results show that under current cost estimates and technical limitations the multi-layered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the two-tier South African tariff scheme.

The effects of running cadence manipulation on plantar loading in healthy runners.

PubMed

Wellenkotter, J; Kernozek, T W; Meardon, S; Suchomel, T

2014-08-01

Our purpose was to evaluate effects of cadence manipulation on plantar loading during running. Participants (n=38) ran on a treadmill at their preferred speed in 3 conditions: preferred, 5% increased, and 5% decreased while measured using in-shoe sensors. Data (contact time [CT], peak force [PF], force time integral [FTI], pressure time integral [PTI] and peak pressure [PP]) were recorded for 30 right footfalls. Multivariate analysis was performed to detect differences in loading between cadences in the total foot and 4 plantar regions. Differences in plantar loading occurred between cadence conditions. Total foot CT and PF were lower with a faster cadence, but no total foot PP differences were observed. Faster cadence reduced CT, pressure and force variables in both the heel and metatarsal regions. Increasing cadence did not elevate metatarsal loads; rather, total foot and all regions were reduced when healthy runners increased their cadence. If a 5% increase in cadence from preferred were maintained over each mile run the impulse at the heel would be reduced by an estimated 565 body weights*s (BW*s) and the metatarsals 140-170 BW*s per mile run despite the increased steps taken. Increasing cadence may benefit overuse injuries associated with elevated plantar loading. © Georg Thieme Verlag KG Stuttgart · New York.

High-Reflectivity Coatings for a Vacuum Ultraviolet Spectropolarimeter

NASA Astrophysics Data System (ADS)

Narukage, Noriyuki; Kubo, Masahito; Ishikawa, Ryohko; Ishikawa, Shin-nosuke; Katsukawa, Yukio; Kobiki, Toshihiko; Giono, Gabriel; Kano, Ryouhei; Bando, Takamasa; Tsuneta, Saku; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; McCandless, Jim; Chen, Jianrong; Choi, Joanne

2017-03-01

Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-α (Lyα; 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Lyα optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Lyα, whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (˜ 5 % on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Lyα line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.

A novel algorithm for Bluetooth ECG.

PubMed

Pandya, Utpal T; Desai, Uday B

2012-11-01

In wireless transmission of ECG, data latency will be significant when battery power level and data transmission distance are not maintained. In applications like home monitoring or personalized care, to overcome the joint effect of previous issues of wireless transmission and other ECG measurement noises, a novel filtering strategy is required. Here, a novel algorithm, identified as peak rejection adaptive sampling modified moving average (PRASMMA) algorithm for wireless ECG is introduced. This algorithm first removes error in bit pattern of received data if occurred in wireless transmission and then removes baseline drift. Afterward, a modified moving average is implemented except in the region of each QRS complexes. The algorithm also sets its filtering parameters according to different sampling rate selected for acquisition of signals. To demonstrate the work, a prototyped Bluetooth-based ECG module is used to capture ECG with different sampling rate and in different position of patient. This module transmits ECG wirelessly to Bluetooth-enabled devices where the PRASMMA algorithm is applied on captured ECG. The performance of PRASMMA algorithm is compared with moving average and S-Golay algorithms visually as well as numerically. The results show that the PRASMMA algorithm can significantly improve the ECG reconstruction by efficiently removing the noise and its use can be extended to any parameters where peaks are importance for diagnostic purpose.

Effect of armor and carrying load on body balance and leg muscle function.

PubMed

Park, Huiju; Branson, Donna; Kim, Seonyoung; Warren, Aric; Jacobson, Bert; Petrova, Adriana; Peksoz, Semra; Kamenidis, Panagiotis

2014-01-01

This study investigated the impact of weight and weight distribution of body armor and load carriage on static body balance and leg muscle function. A series of human performance tests were conducted with seven male, healthy, right-handed military students in seven garment conditions with varying weight and weight distributions. Static body balance was assessed by analyzing the trajectory of center of plantar pressure and symmetry of weight bearing in the feet. Leg muscle functions were assessed by analyzing the peak electromyography amplitude of four selected leg muscles during walking. Results of this study showed that uneven weight distribution of garment and load beyond an additional 9 kg impaired static body balance as evidenced by increased sway of center of plantar pressure and asymmetry of weight bearing in the feet. Added weight on non-dominant side of the body created greater impediment to static balance. Increased garment weight also elevated peak EMG amplitude in the rectus femoris to maintain body balance and in the medial gastrocnemius to increase propulsive force. Negative impacts on balance and leg muscle function with increased carrying loads, particularly with an uneven weight distribution, should be stressed to soldiers, designers, and sports enthusiasts. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of swimming performance from physical, physiological, and biomechanical parameters in young swimmers.

PubMed

Jürimäe, Jaak; Haljaste, Kaja; Cicchella, Antonio; Lätt, Evelin; Purge, Priit; Leppik, Aire; Jürimäe, Toivo

2007-02-01

The purpose of this study was to examine the influence of the energy cost of swimming, body composition, and technical parameters on swimming performance in young swimmers. Twenty-nine swimmers, 15 prepubertal (11.9 +/- 0.3 years; Tanner Stages 1-2) and 14 pubertal (14.3 +/- 1.4 years; Tanner Stages 3-4) boys participated in the study. The energy cost of swimming (Cs) and stroking parameters were assessed over maximal 400-m front-crawl swimming in a 25-m swimming pool. The backward extrapolation technique was used to evaluate peak oxygen consumption (VO2peak). A stroke index (SI; m2 . s(-1) . cycles(-1)) was calculated by multiplying the swimming speed by the stroke length. VO2peak results were compared with VO2peak test in the laboratory (bicycle, 2.86 +/- 0.74 L/min, vs. in water, 2.53 +/- 0.50 L/min; R2 = .713; p = .0001). Stepwise-regression analyses revealed that SI (R2 = .898), in-water VO2peak (R2 = .358), and arm span (R2 = .454) were the best predictors of swimming performance. The backward-extrapolation method could be used to assess VO2peak in young swimmers. SI, arm span, and VO2peak appear to be the major determinants of front-crawl swimming performance in young swimmers.

Peak torque and rate of torque development influence on repeated maximal exercise performance: contractile and neural contributions.

PubMed

Morel, Baptiste; Rouffet, David M; Saboul, Damien; Rota, Samuel; Clémençon, Michel; Hautier, Christophe A

2015-01-01

Rapid force production is critical to improve performance and prevent injuries. However, changes in rate of force/torque development caused by the repetition of maximal contractions have received little attention. The aim of this study was to determine the relative influence of rate of torque development (RTD) and peak torque (T(peak)) on the overall performance (i.e. mean torque, T(mean)) decrease during repeated maximal contractions and to investigate the contribution of contractile and neural mechanisms to the alteration of the various mechanical variables. Eleven well-trained men performed 20 sets of 6-s isokinetic maximal knee extensions at 240° · s(-1), beginning every 30 seconds. RTD, T(peak) and T(mean) as well as the Rate of EMG Rise (RER), peak EMG (EMG(peak)) and mean EMG (EMG(mean)) of the vastus lateralis were monitored for each contraction. A wavelet transform was also performed on raw EMG signal for instant mean frequency (if(mean)) calculation. A neuromuscular testing procedure was carried out before and immediately after the fatiguing protocol including evoked RTD (eRTD) and maximal evoked torque (eT(peak)) induced by high frequency doublet (100 Hz). T(mean) decrease was correlated to RTD and T(peak) decrease (R(²) = 0.62; p<0.001; respectively β=0.62 and β=0.19). RER, eRTD and initial if(mean) (0-225 ms) decreased after 20 sets (respectively -21.1 ± 14.1, -25 ± 13%, and ~20%). RTD decrease was correlated to RER decrease (R(²) = 0.36; p<0.05). The eT(peak) decreased significantly after 20 sets (24 ± 5%; p<0.05) contrary to EMG(peak) (-3.2 ± 19.5 %; p=0.71). Our results show that reductions of RTD explained part of the alterations of the overall performance during repeated moderate velocity maximal exercise. The reductions of RTD were associated to an impairment of the ability of the central nervous system to maximally activate the muscle in the first milliseconds of the contraction.

L-alanyl-L-glutamine ingestion maintains performance during a competitive basketball game.

PubMed

Hoffman, Jay R; Williams, David R; Emerson, Nadia S; Hoffman, Mattan W; Wells, Adam J; McVeigh, Daniele M; McCormack, William P; Mangine, Gerald T; Gonzalez, Adam M; Fragala, Maren S

2012-03-07

The purpose of this study was to examine the efficacy of L-alanyl-L-glutamine (AG) ingestion on basketball performance, including jump power, reaction time, shooting accuracy and fatigue. Ten women (21.2 ± 1.6 years; height: 177.8 ± 8.7 cm; body mass: 73.5 ± 8.0 kg), all scholarship NCAA Division I basketball players, volunteered for this study. Subjects participated in four trials, each consisting of a 40-min basketball game with controlled time-outs for rehydration. During the first trial (DHY) subjects were not allowed to rehydrate, and the total weight lost during the contest was used to determine fluid replenishment during the subsequent three trials. During one trial subjects consumed only water (W), while during the other two trials subjects consumed the AG supplement mixed in water using either a low dose (1 g per 500 ml) (AG1) or high dose (2 g per 500 ml) (AG2) concentration. All data assessed prior to and following each game were converted into a Δ score (Post results - Pre results). All performance data were then analyzed using a one-way repeated measures analysis of variance. During DHY subjects lost 1.72 ± 0.42 kg (2.3%) of their body mass. No differences in fluid intake (1.55 ± 0.43 L) were seen between rehydration trials. A 12.5% (p = 0.016) difference in basketball shooting performance was noted between DHY and AG1 and an 11.1% (p = 0.029) difference was seen between AG1 and W. Visual reaction time was significantly greater following AG1 (p = 0.014) compared to DHY. Differences (p = 0.045) in fatigue, as determined by player loads, were seen only between AG2 and DHY. No differences were seen in peak or mean vertical jump power during any trial. Rehydration with AG appears to maintain basketball skill performance and visual reaction time to a greater extent than water only.

Probiotic Bacillus coagulans GBI-30, 6086 reduces exercise-induced muscle damage and increases recovery

PubMed Central

Jäger, Ralf; Shields, Kevin A.; Lowery, Ryan P.; De Souza, Eduardo O.; Partl, Jeremy M.; Hollmer, Chase; Purpura, Martin

2016-01-01

Objective. Probiotics have been reported to support healthy digestive and immune function, aid in protein absorption, and decrease inflammation. Further, a trend to increase vertical jump power has been observed following co-administration of protein and probiotics in resistance-trained subjects. However, to date the potential beneficial effect of probiotics on recovery from high intensity resistance exercise have yet to be explored. Therefore, this study examined the effect of co-administration of protein and probiotics on muscle damage, recovery and performance following a damaging exercise bout. Design. Twenty nine (n = 29) recreationally-trained males (mean ± SD; 21.5 ± 2.8 years; 89.7 ± 28.2 kg; 177.4 ± 8.0 cm) were assigned to consume either 20 g of casein (PRO) or 20 g of casein plus probiotic (1 billion CFU Bacillus coagulans GBI-30, 6086, PROBC) in a crossover, diet-controlled design. After two weeks of supplementation, perceptional measures, athletic performance, and muscle damage were analyzed following a damaging exercise bout. Results. The damaging exercise bout significantly increased muscle soreness, and reduced perceived recovery; however, PROBC significantly increased recovery at 24 and 72 h, and decreased soreness at 72 h post exercise in comparison to PRO. Perceptual measures were confirmed by increases in CK (PRO: +266.8%, p = 0.0002; PROBC: +137.7%, p = 0.01), with PROBC showing a trend towards reduced muscle damage (p = 0.08). The muscle-damaging exercise resulted in significantly increased muscle swelling and Blood Urea Nitrogen levels in both conditions with no difference between groups. The strenuous exercise significantly reduced athletic performance in PRO (Wingate Peak Power; PRO: (−39.8 watts, −5.3%, p = 0.03)), whereas PROBC maintained performance (+10.1 watts, +1.7%). Conclusions. The results provide evidence that probiotic supplementation in combination with protein tended to reduce indices of muscle damage, improves recovery, and maintains physical performance subsequent to damaging exercise. PMID:27547577

Theoretical dosimetric evaluation of carbon and oxygen minibeam radiation therapy.

PubMed

González, Wilfredo; Peucelle, Cécile; Prezado, Yolanda

2017-05-01

Charged particles have several advantages over x-ray radiations, both in terms of physics and radiobiology. The combination of these advantages with those of minibeam radiation therapy (MBRT) could help enhancing the therapeutic index for some cancers with poor prognosis. Among the different ions explored for therapy, carbon ions are considered to provide the optimum physical and biological characteristics. Oxygen could be advantageous due to a reduced oxygen enhancement ratio along with a still moderate biological entrance dose. The aforementioned reasons justified an in-depth evaluation of the dosimetric features of carbon and oxygen minibeam radiation therapy to establish the interest of further explorations of this avenue. The GATE/Geant4 6.2 Monte Carlo simulation platform was employed to simulate arrays of rectangular carbon and oxygen minibeams (600 μm × 2 cm) at a water phantom entrance. They were assumed to be generated by means of a magnetic focusing. The irradiations were performed with a 2-cm-long spread-out Bragg peak (SOBP) centered at 7-cm-depth. Several center-to-center (c-t-c) distances were considered. Peak and valley doses, as well as peak-to-valley dose ratio (PVDR) and the relative contribution of nuclear fragments and electromagnetic processes were assessed. In addition, the type and proportion of the secondary nuclear fragments were evaluated in both peak and valley regions. Carbon and oxygen MBRT lead to very similar dose distributions. No significant advantage of oxygen over carbon ions was observed from physical point of view. Favorable dosimetric features were observed for both ions. Thanks to the reduced lateral scattering, the standard shape of the depth dose curves (in the peaks) is maintained even for submillimetric beam sizes. When a narrow c-t-c is considered (910-980 μm), a (quasi) homogenization of the dose can be obtained at the target, while a spatial fractionation of the dose is maintained in the proximal normal tissues with low PVDR. In contrast when a larger c-t-c is used (3500 μm) extremely high PVDR (≥ 50) are obtained in normal tissues, corresponding to very low valley doses. This suggests that carbon and oxygen MBRT might lead to a significant reduction of normal tissue complication probability. The main participant to the valley doses are secondary nuclear products at all depths. Among them the highest yield in normal tissues corresponds to the lightest fragments, neutrons and protons. Heavier fragments are dominant in the valleys only at the target position, which might favor tumor control. The computed dose distributions suggest that a spatial fractionation of the dose combined to the use of submillimetric field sizes might allow profiting from the high efficiency of carbon and oxygen ions for the treatment of radioresistant tumors, while preserving normal tissues. Only biological experiments could confirm the shifting of the normal tissue complication probability curves. The authors' results support the further exploration of this avenue. © 2017 American Association of Physicists in Medicine.

Peak power in the hexagonal barbell jump squat and its relationship to jump performance and acceleration in elite rugby union players.

PubMed

Turner, Thomas S; Tobin, Daniel P; Delahunt, Eamonn

2015-05-01

Recent research suggests that jump squats with a loaded hexagonal barbell are superior for peak power production to comparable loads in a traditional barbell loaded jump squat. The aim of this study was to investigate the relationship between relative peak power output during performance of the hexagonal barbell jump squat (HBJS), countermovement jump (CMJ) height, and linear acceleration speed in rugby union players. Seventeen professional rugby union players performed 10- and 20-m sprints, followed by a set of 3 unloaded CMJs and a set of 3 HBJS at a previously determined optimal load corresponding with peak power output. The relationship between HBJS relative peak power output, 10- and 20-m sprint time, and CMJ height was investigated using correlation analysis. The contribution of HBJS relative peak power output and CMJ height to 10- and 20-m sprint time was investigated using standard multiple regression. Strong, significant, inverse correlations were observed between HBJS relative peak power output, 10-m sprint time (r = -0.70, p < 0.01), and 20-m sprint time (r = -0.75, p < 0.01). A strong, significant, positive correlation was observed between HBJS relative peak power output and CMJ height (r = 0.80, p < 0.01). Together, HBJS relative peak power output and CMJ height explained 46% of the variance in 10-m sprint time while explaining 59% of the variance in 20-m sprint time. The findings of the current study demonstrate a significant relationship between relative peak power in the HBJS and athletic performance as quantified by CMJ height and 10- and 20-m sprint time.

Comparison of public peak detection algorithms for MALDI mass spectrometry data analysis.

PubMed

Yang, Chao; He, Zengyou; Yu, Weichuan

2009-01-06

In mass spectrometry (MS) based proteomic data analysis, peak detection is an essential step for subsequent analysis. Recently, there has been significant progress in the development of various peak detection algorithms. However, neither a comprehensive survey nor an experimental comparison of these algorithms is yet available. The main objective of this paper is to provide such a survey and to compare the performance of single spectrum based peak detection methods. In general, we can decompose a peak detection procedure into three consequent parts: smoothing, baseline correction and peak finding. We first categorize existing peak detection algorithms according to the techniques used in different phases. Such a categorization reveals the differences and similarities among existing peak detection algorithms. Then, we choose five typical peak detection algorithms to conduct a comprehensive experimental study using both simulation data and real MALDI MS data. The results of comparison show that the continuous wavelet-based algorithm provides the best average performance.

Nonlinear temperature dependence of glue-induced birefringence in polarization maintaining FBG sensors

NASA Astrophysics Data System (ADS)

Hopf, Barbara; Koch, Alexander W.; Roths, Johannes

2016-05-01

Glue-induced stresses decrease the accuracy of surface-mounted fiber Bragg gratings (FBG). Significant temperature dependent glue-induced birefringence was verified when a thermally cured epoxy-based bonding technique had been used. Determining the peak separation of two azimuthally aligned FBGs in PM fibers combined with a polarization resolved measurement set-up in a temperature range between -30°C and 150°C revealed high glue-induced stresses at low temperatures. Peak separations of about 60 pm and a nonlinear temperature dependence of the glue-induced birefringence due to stress relaxation processes and a visco-elastic behavior of the used adhesive have been shown.

Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance.

PubMed

Knaier, Raphael; Schäfer, Juliane; Rossmeissl, Anja; Klenk, Christopher; Hanssen, Henner; Höchsmann, Christoph; Cajochen, Christian; Schmidt-Trucksäss, Arno

2017-01-01

Many sports competitions take place during television prime time, a time of the day when many athletes have already exceeded their time of peak performance. We assessed the effect of different light exposure modalities on physical performance and melatonin levels in athletes during prime time. Seventy-two young, male elite athletes with a median (interquartile range) age of 23 (21; 29) years and maximum oxygen uptake (VO2max) of 63 (58; 66) ml/kg/min were randomly assigned to three different light exposure groups: bright light (BRIGHT), blue monochromatic light (BLUE), and control light (CONTROL). Each light exposure lasted 60 min and was scheduled to start 17 h after each individual's midpoint of sleep (median time: 9:17 pm). Immediately after light exposure, a 12-min time trial was performed on a bicycle ergometer. The test supervisor and participants were blinded to the light condition each participant was exposed to. The median received light intensities and peak wavelengths (photopic lx/nm) measured at eye level were 1319/545 in BRIGHT, 203/469 in BLUE, and 115/545 in CONTROL. In a multivariate analysis adjusted for individual VO2max, total work performed in 12 min did not significantly differ between the three groups. The amount of exposure to non-image forming light was positively associated with the performance gain during the time trial, defined as the ratio of the work performed in the first and last minute of the time trial, and with stronger melatonin suppression. Specifically, a tenfold increase in the exposure to melanopic light was associated with a performance gain of 8.0% (95% confidence interval: 2.6, 13.3; P = 0.004) and a melatonin decrease of -0.9 pg/ml (95% confidence interval: -1.5, -0.3; P = 0.006). Exposure to bright or blue light did not significantly improve maximum cycling performance in a 12-min all-out time trial. However, it is noteworthy that the estimated difference of 4.1 kJ between BRIGHT and CONTROL might represent an important performance advantage justifying further studies. In conclusion, we report novel evidence that evening light exposure, which strongly impacts the human circadian timing system, enables elite athletes to better maintain performance across a 12-min cycling time trial.

Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance

PubMed Central

Knaier, Raphael; Schäfer, Juliane; Rossmeissl, Anja; Klenk, Christopher; Hanssen, Henner; Höchsmann, Christoph; Cajochen, Christian; Schmidt-Trucksäss, Arno

2017-01-01

Many sports competitions take place during television prime time, a time of the day when many athletes have already exceeded their time of peak performance. We assessed the effect of different light exposure modalities on physical performance and melatonin levels in athletes during prime time. Seventy-two young, male elite athletes with a median (interquartile range) age of 23 (21; 29) years and maximum oxygen uptake (VO2max) of 63 (58; 66) ml/kg/min were randomly assigned to three different light exposure groups: bright light (BRIGHT), blue monochromatic light (BLUE), and control light (CONTROL). Each light exposure lasted 60 min and was scheduled to start 17 h after each individual's midpoint of sleep (median time: 9:17 pm). Immediately after light exposure, a 12-min time trial was performed on a bicycle ergometer. The test supervisor and participants were blinded to the light condition each participant was exposed to. The median received light intensities and peak wavelengths (photopic lx/nm) measured at eye level were 1319/545 in BRIGHT, 203/469 in BLUE, and 115/545 in CONTROL. In a multivariate analysis adjusted for individual VO2max, total work performed in 12 min did not significantly differ between the three groups. The amount of exposure to non-image forming light was positively associated with the performance gain during the time trial, defined as the ratio of the work performed in the first and last minute of the time trial, and with stronger melatonin suppression. Specifically, a tenfold increase in the exposure to melanopic light was associated with a performance gain of 8.0% (95% confidence interval: 2.6, 13.3; P = 0.004) and a melatonin decrease of −0.9 pg/ml (95% confidence interval: −1.5, −0.3; P = 0.006). Exposure to bright or blue light did not significantly improve maximum cycling performance in a 12-min all-out time trial. However, it is noteworthy that the estimated difference of 4.1 kJ between BRIGHT and CONTROL might represent an important performance advantage justifying further studies. In conclusion, we report novel evidence that evening light exposure, which strongly impacts the human circadian timing system, enables elite athletes to better maintain performance across a 12-min cycling time trial. PMID:28507521

Influence of the "Slingshot" bench press training aid on bench press kinematics and neuromuscular activity in competitive powerlifters.

PubMed

Dugdale, James H; Hunter, Angus; Di Virgilio, Thomas; Macgregor, Lewis J; Hamilton, D Lee

2017-02-13

This study examined the acute effects of the 'Slingshot' on bench-press performance, prime-mover surface electromyographic (sEMG) amplitude, and barbell velocity during maximal and submaximal bench-pressing in competitive male powerlifters. Fifteen male powerlifters (mean ± SD age: 27.05 ± 5.94 years; mass: 94.15kg; 1RM bench-press: 139.7 ± 16.79kg) participated in the study. Bench-press strength, average barbell velocity, and sEMG amplitude of the prime mover muscles (triceps brachii, pectoralis major and anterior deltoid) were measured during two conditions; 'Raw' (without use of any assistance) and 'Slingshot' [using the 'Slingshot' to perform both the weight achieved during 'Raw' 1RM testing (Raw max/SS), and absolute 1RM using the 'Slingshot' (SS)]. The results showed that the 'Slingshot' significantly increased bench press 1RM performance by a mean ± SD of 20.67kg ± 3.4kg. Barbell velocity and stick point analysis indicate that this improvement is likely driven by an increase in peak and pre-stick barbell velocity as triceps RMS was lower throughout all rep max phases with the 'Slingshot'. The 'Slingshot' also caused reductions in RMS, specifically of the triceps at all rep ranges but barbell velocity was better maintained in the last reps of all sets. These data indicate that the 'Slingshot' specifically de-loaded the triceps muscle throughout all rep ranges and provide assistance to maintaining barbell velocity under fatigue during later repetitions of multiple-repetition sets. The 'Slingshot' training aid could therefore be used in de-load phases of bench press training or as an over-reaching and velocity training aid.

Detecting and accounting for multiple sources of positional variance in peak list registration analysis and spin system grouping.

PubMed

Smelter, Andrey; Rouchka, Eric C; Moseley, Hunter N B

2017-08-01

Peak lists derived from nuclear magnetic resonance (NMR) spectra are commonly used as input data for a variety of computer assisted and automated analyses. These include automated protein resonance assignment and protein structure calculation software tools. Prior to these analyses, peak lists must be aligned to each other and sets of related peaks must be grouped based on common chemical shift dimensions. Even when programs can perform peak grouping, they require the user to provide uniform match tolerances or use default values. However, peak grouping is further complicated by multiple sources of variance in peak position limiting the effectiveness of grouping methods that utilize uniform match tolerances. In addition, no method currently exists for deriving peak positional variances from single peak lists for grouping peaks into spin systems, i.e. spin system grouping within a single peak list. Therefore, we developed a complementary pair of peak list registration analysis and spin system grouping algorithms designed to overcome these limitations. We have implemented these algorithms into an approach that can identify multiple dimension-specific positional variances that exist in a single peak list and group peaks from a single peak list into spin systems. The resulting software tools generate a variety of useful statistics on both a single peak list and pairwise peak list alignment, especially for quality assessment of peak list datasets. We used a range of low and high quality experimental solution NMR and solid-state NMR peak lists to assess performance of our registration analysis and grouping algorithms. Analyses show that an algorithm using a single iteration and uniform match tolerances approach is only able to recover from 50 to 80% of the spin systems due to the presence of multiple sources of variance. Our algorithm recovers additional spin systems by reevaluating match tolerances in multiple iterations. To facilitate evaluation of the algorithms, we developed a peak list simulator within our nmrstarlib package that generates user-defined assigned peak lists from a given BMRB entry or database of entries. In addition, over 100,000 simulated peak lists with one or two sources of variance were generated to evaluate the performance and robustness of these new registration analysis and peak grouping algorithms.

Association of Quadriceps Strength and Psychosocial Factors With Single-Leg Hop Performance in Patients With Meniscectomy.

PubMed

Hsu, Chao-Jung; George, Steven Z; Chmielewski, Terese L

2016-12-01

Clinicians use the single-leg hop test to assess readiness for return to sports after knee injury. Few studies have reported the results of single-leg hop testing after meniscectomy. Additionally, the contributions of impairments in quadriceps strength and psychosocial factors to single-leg hop performance are unknown. To compare single-leg hop performance (distance and landing mechanics) between limbs and to examine the association of single-leg hop performance with quadriceps strength and psychosocial factors in patients with meniscectomy. Descriptive laboratory study. A total of 22 subjects who underwent meniscectomy for traumatic meniscal tears received either standard rehabilitation alone or with additional quadriceps strengthening. Testing was conducted immediately postrehabilitation and at 1 year postsurgery. A single-leg hop test was performed bilaterally, and hop distance was used to create a hop symmetry index. Landing mechanics (peak knee flexion angle, knee extension moment, and peak vertical ground-reaction force) were analyzed with a motion-capture system and a force plate. An isokinetic dynamometer (60 deg/s) assessed knee extensor peak torque and rate of torque development (RTD 0-200ms and RTD 0-peak torque ). Questionnaires assessed fear of reinjury (Tampa Scale for Kinesiophobia [TSK-11]) and self-efficacy (Knee Activity Self-Efficacy [KASE]). Rehabilitation groups did not significantly differ in single-leg hop performance; therefore, groups were combined for further analyses. The mean hop symmetry index was 88.6% and 98.9% at postrehabilitation and 1 year postsurgery, respectively. Compared with the nonsurgical limb, the surgical limb showed decreased peak knee flexion angle at postrehabilitation and decreased knee extension moment at 1 year postsurgery. The hop symmetry index was positively associated with peak torque, RTD 0-200ms , and the KASE score at postrehabilitation. Moreover, at postrehabilitation, the peak knee flexion angle was positively associated with peak torque and RTD 0-200ms , and the knee extension moment was positively associated with RTD 0-200ms . At 1 year postsurgery, peak knee flexion angle and knee extension moment were both positively associated with peak torque, RTD 0-200ms , and RTD 0-peak torque . Although the hop symmetry index could be considered satisfactory for returning to sports, asymmetries in landing mechanics still exist in the first year postmeniscectomy. Greater quadriceps strength was associated with greater single-leg hop distance and better landing mechanics at both postrehabilitation and 1 year postsurgery. Knee activity self-efficacy was the only psychosocial factor associated with single-leg hop performance and isolated to a positive association with single-leg hop distance at postrehabilitation. Rate of development is not typically measured in the clinic but can be an additional quadriceps measure to monitor for single-leg hop performance. Quadriceps strength and psychosocial factors appear to have separate influence on single-leg hop performance after meniscectomy, which has implications for developing appropriate interventions for optimal single-leg hop performance.

Association of Quadriceps Strength and Psychosocial Factors With Single-Leg Hop Performance in Patients With Meniscectomy

PubMed Central

Hsu, Chao-Jung; George, Steven Z.; Chmielewski, Terese L.

2016-01-01

Background: Clinicians use the single-leg hop test to assess readiness for return to sports after knee injury. Few studies have reported the results of single-leg hop testing after meniscectomy. Additionally, the contributions of impairments in quadriceps strength and psychosocial factors to single-leg hop performance are unknown. Purpose: To compare single-leg hop performance (distance and landing mechanics) between limbs and to examine the association of single-leg hop performance with quadriceps strength and psychosocial factors in patients with meniscectomy. Study Design: Descriptive laboratory study. Methods: A total of 22 subjects who underwent meniscectomy for traumatic meniscal tears received either standard rehabilitation alone or with additional quadriceps strengthening. Testing was conducted immediately postrehabilitation and at 1 year postsurgery. A single-leg hop test was performed bilaterally, and hop distance was used to create a hop symmetry index. Landing mechanics (peak knee flexion angle, knee extension moment, and peak vertical ground-reaction force) were analyzed with a motion-capture system and a force plate. An isokinetic dynamometer (60 deg/s) assessed knee extensor peak torque and rate of torque development (RTD0-200ms and RTD0–peak torque). Questionnaires assessed fear of reinjury (Tampa Scale for Kinesiophobia [TSK-11]) and self-efficacy (Knee Activity Self-Efficacy [KASE]). Results: Rehabilitation groups did not significantly differ in single-leg hop performance; therefore, groups were combined for further analyses. The mean hop symmetry index was 88.6% and 98.9% at postrehabilitation and 1 year postsurgery, respectively. Compared with the nonsurgical limb, the surgical limb showed decreased peak knee flexion angle at postrehabilitation and decreased knee extension moment at 1 year postsurgery. The hop symmetry index was positively associated with peak torque, RTD0-200ms, and the KASE score at postrehabilitation. Moreover, at postrehabilitation, the peak knee flexion angle was positively associated with peak torque and RTD0-200ms, and the knee extension moment was positively associated with RTD0-200ms. At 1 year postsurgery, peak knee flexion angle and knee extension moment were both positively associated with peak torque, RTD0-200ms, and RTD0–peak torque. Conclusion: Although the hop symmetry index could be considered satisfactory for returning to sports, asymmetries in landing mechanics still exist in the first year postmeniscectomy. Greater quadriceps strength was associated with greater single-leg hop distance and better landing mechanics at both postrehabilitation and 1 year postsurgery. Knee activity self-efficacy was the only psychosocial factor associated with single-leg hop performance and isolated to a positive association with single-leg hop distance at postrehabilitation. Clinical Relevance: Rate of development is not typically measured in the clinic but can be an additional quadriceps measure to monitor for single-leg hop performance. Quadriceps strength and psychosocial factors appear to have separate influence on single-leg hop performance after meniscectomy, which has implications for developing appropriate interventions for optimal single-leg hop performance. PMID:28210647

Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter.

PubMed

Bartsch, Adam; Samorezov, Sergey; Benzel, Edward; Miele, Vincent; Brett, Daniel

2014-11-01

Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision. But no instrument exists to accurately and precisely quantify single head impact events. Our goal is to develop a practical single event head impact dosimeter known as "Intelligent Mouthguard" and quantify its performance on the benchtop, in vitro and in vivo. In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration. After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football, IMG=1.00REF-1.1g, R2=0.99; maximum time of peak XYZ component imprecision 3.6g and 370 rad/s2; maximum time of peak azimuth and elevation imprecision 4.8° and 2.9°; maximum average XYZ component temporal imprecision 3.3g and 390 rad/s2. Boxing, IMG=1.00REF-0.9 g, R2=0.99, R2=0.98; maximum time of peak XYZ component imprecision 3.9 g and 390 rad/s2, maximum time of peak azimuth and elevation imprecision 2.9° and 2.1°; average XYZ component temporal imprecision 4.0 g and 440 rad/s2. In vivo Intelligent Mouthguard true positive head impacts from American football players and amateur boxers have temporal characteristics (first harmonic frequency from 35 Hz to 79 Hz) within our tested benchtop (first harmonic frequency<180 Hz) and in vitro (first harmonic frequency<100 Hz) ranges. Our conclusions apply only to situations where the rigid body assumption is valid, sensor-skull coupling is maintained and the ranges of tested parameters and harmonics fall within the boundaries of harmonics validated in vitro. For these situations, Intelligent Mouthguard qualifies as a single event dosimeter in American football and Boxing.

Polarization dependence of Brillouin linewidth and peak frequency due to fiber inhomogeneity in single mode fiber and its impact on distributed fiber Brillouin sensing.

PubMed

Xie, Shangran; Pang, Meng; Bao, Xiaoyi; Chen, Liang

2012-03-12

The dependence of Brillouin linewidth and peak frequency on lightwave state of polarization (SOP) due to fiber inhomogeneity in single mode fiber (SMF) is investigated by using Brillouin optical time domain analysis (BOTDA) system. Theoretical analysis shows fiber inhomogeneity leads to fiber birefringence and sound velocity variation, both of which can cause the broadening and asymmetry of the Brillouin gain spectrum (BGS) and thus contribute to the variation of Brillouin linewidth and peak frequency with lightwave SOP. Due to fiber inhomogeneity both in lateral profile and longitudinal direction, the measured BGS is the superposition of several spectrum components with different peak frequencies within the interaction length. When pump or probe SOP changes, both the peak Brillouin gain and the overlapping area of the optical and acoustic mode profile that determine the peak efficiency of each spectrum component vary within the interaction length, which further changes the linewidth and peak frequency of the superimposed BGS. The SOP dependence of Brillouin linewidth and peak frequency was experimentally demonstrated and quantified by measuring the spectrum asymmetric factor and fitting obtained effective peak frequency respectively via BOTDA system on standard step-index SMF-28 fiber. Experimental results show that on this fiber the Brillouin spectrum asymmetric factor and effective peak frequency vary in the range of 2% and 0.06MHz respectively over distance with orthogonal probe input SOPs. Experimental results also show that in distributed fiber Brillouin sensing, polarization scrambler (PS) can be used to reduce the SOP dependence of Brillouin linewidth and peak frequency caused by fiber inhomogeneity in lateral profile, however it maintains the effects caused by fiber inhomogeneity in longitudinal direction. In the case of non-ideal polarization scrambling using practical PS, the fluctuation of effective Brillouin peak frequency caused by fiber inhomogeneity provides another limit of sensing frequency resolution of distributed fiber Brillouin sensor.

Effects of grab bar on utilized friction and dynamic stability when elderly people enter the bathtub.

PubMed

Sekiguchi, Yusuke; Kato, Tomohisa; Honda, Keita; Kanetaka, Hiroyasu; Izumi, Shin-Ichi

2017-08-01

The effect of the grab bar on dynamic stability when elderly people enter the bathtub remains unclear. The purpose of the present study is to examine the age-related effect of the grab bar on dynamic stability during lateral stepping over an obstacle when entering bathtub. Sixteen young, healthy adults and sixteen elderly adults participated. The subjects performed lateral stepping over an obstacle with and without vertical and horizontal bars. Displacement and velocity of the center of mass and utilized friction, which is the required coefficient of friction to avoid slipping, were simultaneously measured by a three-dimensional motion analysis system and two force plates. A post hoc test for two-way ANOVA revealed that velocity of the center of mass in the vertical direction (p<0.05) and peak-to-peak values of the center of mass in the lateral (p<0.05) and vertical directions (p<0.05) with each grab bar were significantly slower and smaller than those without the grab bar in young and elderly people. Moreover, the utilized friction at push off of the trailing leg with the vertical bar in elderly people was lower (p<0.05) than that in participants without the grab bar. The use of each grab bar while performing a lateral step over an obstacle may help maintaining balance in lateral and vertical directions. However, use of the vertical bar while lateral stepping over an object in elderly people may need low utilized friction to prevent slipping. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pointing the foot without sickling: an examination of ankle movement during jumping.

PubMed

Jarvis, Danielle N; Kulig, Kornelia

2015-03-01

The sauté is a relatively simple dance jump that can be performed by both highly skilled dancers and non-dancers. However, there are characteristics of jumping unique to trained dancers, especially in terms of foot and ankle movement during flight. Dancers are trained not to "sickle, " or to avoid the anatomically coupled ankle inversion that occurs with plantar flexion, maintaining the appearance of a straight line through the lower leg and foot. The purpose of this study was to examine ankle movements in elite dancers compared to non-dancers. Twenty healthy females, 10 with no prior dance training and 10 professional dancers, performed 20 consecutive sautés while three-dimensional kinematic data were collected. Sagittal and frontal plane kinematics were calculated and vector coding methods were used to quantify coordination patterns within the ankle in the sagittal and frontal planes. This pattern was chosen for analysis to identify the avoidance of a sickled foot by trained dancers. Peak ankle positions and coordination patterns between groups were examined using independent t-tests (a <0.05). Dancers demonstrated greater peak plantar flexion (p<0.01) and less change in ankle angle during the flight phase (p= 0.01), signifying holding the pointed foot position during flight. There was no statistically significant difference in sagittal and frontal plane ankle coupling (p= 0.15); however, the Cohen's d effect size for the difference in coupling was medium-to-large (0.73). Dynamic analysis of the foot and ankle during jumping demonstrates how elite dancers achieve the aesthetic requirements of dance technique.

Molecular engineering to improve carrier lifetimes for organic photovoltaic devices with thick active layers

DOE PAGES

Oosterhout, Stefan D.; Braunecker, Wade A.; Owczarczyk, Zbyslaw R.; ...

2017-04-27

The morphology of the bulk heterojunction absorber layer in an organic photovoltaic (OPV) device has a profound effect on the electrical properties and efficiency of the device. Previous work has consistently demonstrated that the solubilizing side-chains of the donor material affect these properties and device performance in a non-trivial way. Here, using Time-Resolved Microwave Conductivity (TRMC), we show by direct measurements of carrier lifetimes that the choice of side chains can also make a substantial difference in photocarrier dynamics. We have previously demonstrated a correlation between peak photoconductance measured by TRMC and device efficiencies; here, we demonstrate that TRMC photocarriermore » dynamics have an important bearing on device performance in a case study of devices made from donor materials with linear vs. branched side-chains and with variable active layer thicknesses. We use Grazing-Incidence Wide Angle X-ray Scattering to elucidate the cause of the different carrier lifetimes as a function of different aggregation behavior in the polymers. Consequently, the results help establish TRMC as a technique for screening OPV donor materials whose devices maintain performance in thick active layers (>250 nm) designed to improve light harvesting, film reproducibility, and ease of processing.« less

Nickel-based anode with water storage capability to mitigate carbon deposition for direct ethanol solid oxide fuel cells.

PubMed

Wang, Wei; Su, Chao; Ran, Ran; Zhao, Bote; Shao, Zongping; Tade, Moses O; Liu, Shaomin

2014-06-01

The potential to use ethanol as a fuel places solid oxide fuel cells (SOFCs) as a sustainable technology for clean energy delivery because of the renewable features of ethanol versus hydrogen. In this work, we developed a new class of anode catalyst exemplified by Ni+BaZr0.4Ce0.4Y0.2O3 (Ni+BZCY) with a water storage capability to overcome the persistent problem of carbon deposition. Ni+BZCY performed very well in catalytic efficiency, water storage capability and coking resistance tests. A stable and high power output was well maintained with a peak power density of 750 mW cm(-2) at 750 °C. The SOFC with the new robust anode performed for seven days without any sign of performance decay, whereas SOFCs with conventional anodes failed in less than 2 h because of significant carbon deposition. Our findings indicate the potential applications of these water storage cermets as catalysts in hydrocarbon reforming and as anodes for SOFCs that operate directly on hydrocarbons. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ideal MHD stability and performance of ITER steady-state scenarios with ITBs

NASA Astrophysics Data System (ADS)

Poli, F. M.; Kessel, C. E.; Chance, M. S.; Jardin, S. C.; Manickam, J.

2012-06-01

Non-inductive steady-state scenarios on ITER will need to operate with internal transport barriers (ITBs) in order to reach adequate fusion gain at typical currents of 9 MA. The large pressure gradients at the location of the internal barrier are conducive to the development of ideal MHD instabilities that may limit the plasma performance and may lead to plasma disruptions. Fully non-inductive scenario simulations with five combinations of heating and current drive sources are presented in this work, with plasma currents in the range 7-10 MA. For each configuration the linear, ideal MHD stability is analysed for variations of the Greenwald fraction and of the pressure peaking factor around the operating point, aiming at defining an operational space for stable, steady-state operations at optimized performance. It is shown that plasmas with lower hybrid heating and current drive maintain the minimum safety factor above 1.5, which is desirable in steady-state operations to avoid neoclassical tearing modes. Operating with moderate ITBs at 2/3 of the minor radius, these plasmas have a minimum safety factor above 2, are ideal MHD stable and reach Q ≳ 5 operating above the ideal no-wall limit.

Results from core-edge experiments in high Power, high performance plasmas on DIII-D

DOE PAGES

Petrie, T. W.; Fenstermacher, M. E.; Holcomb, C. T.; ...

2016-12-24

Here, significant challenges to reducing divertor heat flux in highly powered near-double null divertor (DND) hybrid plasmas, while still maintaining both high performance metrics and low enough density for application of RF heating, are identified. For these DNDs on DIII-D, the scaling of the peak heat flux at the outer target (q ⊥ P) ∝ [P SOL x I P] 0.92 for P SOL = 8-19 MW and I P = 1.0–1.4 MA, and is consistent with standard ITPA scaling for single-null H-mode plasmas. Two divertor heat flux reduction methods were tested. First, applying the puff-and-pump radiating divertor to DIII-Dmore » plasmas may be problematical at high power and H98 (≥ 1.5) due to improvement in confinement time with deuterium gas puffing which can lead to unacceptably high core density under certain conditions. Second, q ⊥ P for these high performance DNDs was reduced by ≈35% when an open divertor is closed on the common flux side of the outer divertor target (“semi-slot”) but also that heating near the slot opening is a significant source for impurity contamination of the core.« less

Deficits in Lower Limb Muscle Reflex Contraction Latency and Peak Force Are Associated With Impairments in Postural Control and Gross Motor Skills of Children With Developmental Coordination Disorder: A Cross-Sectional Study.

PubMed

Fong, Shirley S M; Ng, Shamay S M; Guo, X; Wang, Yuling; Chung, Raymond C K; Stat, Grad; Ki, W Y; Macfarlane, Duncan J

2015-10-01

This cross-sectional, exploratory study aimed to compare neuromuscular performance, balance and motor skills proficiencies of typically developing children and those with developmental coordination disorder (DCD) and to determine associations of these neuromuscular factors with balance and motor skills performances in children with DCD.One hundred thirty children with DCD and 117 typically developing children participated in the study. Medial hamstring and gastrocnemius muscle activation onset latencies in response to an unexpected posterior-to-anterior trunk perturbation were assessed by electromyography and accelerometer. Hamstring and gastrocnemius muscle peak force and time to peak force were quantified by dynamometer, and balance and motor skills performances were evaluated with the Movement Assessment Battery for Children (MABC).Independent t tests revealed that children with DCD had longer hamstring and gastrocnemius muscle activation onset latencies (P < 0.001) and lower isometric peak forces (P < 0.001), but not times to peak forces (P > 0.025), than the controls. Multiple regression analysis accounting for basic demographics showed that gastrocnemius peak force was independently associated with the MABC balance subscore and ball skills subscore, accounting for 5.7% (P = 0.003) and 8.5% (P = 0.001) of the variance, respectively. Gastrocnemius muscle activation onset latency also explained 11.4% (P < 0.001) of the variance in the MABC ball skills subscore.Children with DCD had delayed leg muscle activation onset times and lower isometric peak forces. Gastrocnemius peak force was associated with balance and ball skills performances, whereas timing of gastrocnemius muscle activation was a determinant of ball skill performance in the DCD population.

Recovery of atrial function after atrial compartment operation for chronic atrial fibrillation in mitral valve disease.

PubMed

Shyu, K G; Cheng, J J; Chen, J J; Lin, J L; Lin, F Y; Tseng, Y Z; Kuan, P; Lien, W P

1994-08-01

We prospectively studied the recovery of atrial function after atrial compartment operation and mitral valve surgery in patients with chronic atrial fibrillation caused by mitral valve disease. Chronic atrial fibrillation is the most common arrhythmia in mitral valve disease. This arrhythmia is associated with excessive morbidity and mortality. Mitral valve surgery alone rarely eliminates it. Twenty-two patients underwent mitral valve surgery and a new surgical method, atrial compartment operation. Doppler echocardiography was performed in all patients before operation and at 1 week and 2 and 6 months after operation in the successful cardioversion group. Peak early diastolic (E) and atrial (A) filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves were measured. Sinus rhythm was restored immediately after operation in 91% of patients and was maintained for > 1 week in 15 (68%) of 22 patients and > 6 months in 14 (64%) of 22. Eleven of 15 patients had left atrial paralysis (A/E integral ratio 0) at 1 week and 6 of 14 patients at 2 months. Nine of 15 patients had right atrial paralysis (A/E integral ratio 0) at 1 week and 1 of 14 patients at 2 months. Both left and right atrial contractile function (presence of an A wave on Doppler findings) was detected at 6 months in 14 patients. Mean (+/- SD) peak atrial filling velocity of the mitral valve was 15 +/- 26 cm/s at 1 week, 38 +/- 39 cm/s at 2 months and 93 +/- 32 cm/s at 6 months (p < 0.001). Mean peak atrial filling velocity of the tricuspid valve was 14 +/- 19 cm/s at 1 week, 33 +/- 19 cm/s at 2 months and 50 +/- 19 cm/s at 6 months (p < 0.001). Peak early diastolic and atrial filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves increased significantly from 1 week to 6 months. Chronic atrial fibrillation in mitral valve disease can often be eliminated by atrial compartment operation. No surgical mortality or significant complications were encountered. Both left and right atrial function, as manifested by Doppler findings, recover after compartment operation and improve over time. The mechanical function of the right atrium recovers earlier than that of the left.

SUPERVISORY CONTROL FOR PEAK REDUCTION IN COMMERCIAL BUILDINGS WHILE MAINTAINING COMFORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nutaro, James J; Olama, Mohammed M; Kuruganti, Teja

2016-01-01

This paper describes a supervisory control strategy for limiting peak power demand by small and medium commercial buildings while still meeting the business needs of the occupants. This control strategy has two features that make it relevant to new and existing buildings. First, it is designed to operate with building equipment, such as air conditioning and refrigeration systems, as they are presently installed in most small and medium commercial buildings. Because of this, the supervisory control could be realized as a software-only retrofit to existing building management systems. Second, the proposed control acts as a supervisory management layer over existingmore » control systems, rather than replacing them outright. The primary idea of this approach is that the controls for individual building equipment request energy resources for a control action and the supervisory control examines the requests and decides which control actions to allow while satisfying a limit on peak power demand.« less

Autofluorescence of bovine ligamentum nuchae, cartilage, heart valve and lung measured by microscopy and fibre optics.

PubMed

Swatland, H J

1988-09-01

The fluorescence of bovine tissues was measured post mortem by microscopy of frozen sections and by using optical fibres to excite fluorescence and to measure fluorescence emission spectra. Mechanical disruption of the tissue (by comminution or sectioning) did not appreciably change tissue fluorescence spectra. Ligamentum nuchae had the strongest fluorescence and lung tissue had the weakest. In samples measured with a minimum prior exposure to ultraviolet light, the peak fluorescence emission was at 410 or 420 nm (with excitation at 365 nm). Exposure to ultraviolet light for about 1 minute shifted the fluorescence peak to 450 to 470 nm. Further exposure (about 30 minutes) caused a loss of the 450 to 470 nm fluorescence peak, while emissions above 530 nm were maintained or strengthened. Microscopy showed that the fluorescence that was measured by fibre optics from intact connective tissues originated mostly from collagen and elastin fibres.

A generalized approach to automated NMR peak list editing: application to reduced dimensionality triple resonance spectra.

PubMed

Moseley, Hunter N B; Riaz, Nadeem; Aramini, James M; Szyperski, Thomas; Montelione, Gaetano T

2004-10-01

We present an algorithm and program called Pattern Picker that performs editing of raw peak lists derived from multidimensional NMR experiments with characteristic peak patterns. Pattern Picker detects groups of correlated peaks within peak lists from reduced dimensionality triple resonance (RD-TR) NMR spectra, with high fidelity and high yield. With typical quality RD-TR NMR data sets, Pattern Picker performs almost as well as human analysis, and is very robust in discriminating real peak sets from noise and other artifacts in unedited peak lists. The program uses a depth-first search algorithm with short-circuiting to efficiently explore a search tree representing every possible combination of peaks forming a group. The Pattern Picker program is particularly valuable for creating an automated peak picking/editing process. The Pattern Picker algorithm can be applied to a broad range of experiments with distinct peak patterns including RD, G-matrix Fourier transformation (GFT) NMR spectra, and experiments to measure scalar and residual dipolar coupling, thus promoting the use of experiments that are typically harder for a human to analyze. Since the complexity of peak patterns becomes a benefit rather than a drawback, Pattern Picker opens new opportunities in NMR experiment design.

Finger Flexor Force Influences Performance in Senior Male Air Pistol Olympic Shooting

PubMed Central

Mon, Daniel; Zakynthinaki, María S.; Cordente, Carlos A.; Antón, Antonio J. Monroy; Rodríguez, Bárbara Rodríguez; Jiménez, David López

2015-01-01

The ability to stabilize the gun is crucial for performance in Olympic pistol shooting and is thought to be related to the shooters muscular strength. The present study examines the relation between performance and finger flexor force as well as shoulder abduction isometric force in senior male air pistol shooting. 46 Spanish national level shooters served as test subjects of the study. Two maximal force tests were carried out recording handgrip and deltoid force data under competition conditions, during the official training time at national Spanish championships. Performance was measured as the total score of 60 shots at competition. Linear regressions were calculated to examine the relations between performance and peak and average finger flexor forces, peak and average finger flexor forces relative to the BMI, peak and average shoulder abduction isometric forces, peak shoulder abduction isometric force relative to the BMI. The connection between performance and other variables such as age, weight, height, BMI, experience in years and training hours per week was also analyzed. Significant correlations were found between performance at competition and average and peak finger flexor forces. For the rest of the force variables no significant correlations were found. Significant correlations were also found between performance at competition and experience as well as training hours. No significant correlations were found between performance and age, weight, height or BMI. The study concludes that hand grip strength training programs are necessary for performance in air pistol shooting. PMID:26121145

Finger Flexor Force Influences Performance in Senior Male Air Pistol Olympic Shooting.

PubMed

Mon, Daniel; Zakynthinaki, María S; Cordente, Carlos A; Antón, Antonio J Monroy; Rodríguez, Bárbara Rodríguez; Jiménez, David López

2015-01-01

The ability to stabilize the gun is crucial for performance in Olympic pistol shooting and is thought to be related to the shooters muscular strength. The present study examines the relation between performance and finger flexor force as well as shoulder abduction isometric force in senior male air pistol shooting. 46 Spanish national level shooters served as test subjects of the study. Two maximal force tests were carried out recording handgrip and deltoid force data under competition conditions, during the official training time at national Spanish championships. Performance was measured as the total score of 60 shots at competition. Linear regressions were calculated to examine the relations between performance and peak and average finger flexor forces, peak and average finger flexor forces relative to the BMI, peak and average shoulder abduction isometric forces, peak shoulder abduction isometric force relative to the BMI. The connection between performance and other variables such as age, weight, height, BMI, experience in years and training hours per week was also analyzed. Significant correlations were found between performance at competition and average and peak finger flexor forces. For the rest of the force variables no significant correlations were found. Significant correlations were also found between performance at competition and experience as well as training hours. No significant correlations were found between performance and age, weight, height or BMI. The study concludes that hand grip strength training programs are necessary for performance in air pistol shooting.

A comparison of liver function after hepatectomy with inflow occlusion between sevoflurane and propofol anesthesia.

PubMed

Song, J C; Sun, Y M; Yang, L Q; Zhang, M Z; Lu, Z J; Yu, W F

2010-10-01

In this study, we compared liver function tests after hepatectomy with inflow occlusion as a function of propofol versus sevoflurane anesthesia. One hundred patients undergoing elective liver resection with inflow occlusion were randomized into a sevoflurane group or a propofol group. General anesthesia was induced with 3 μg/kg fentanyl, 0.2 mg/kg cisatracurium, and target-controlled infusion of propofol, set at a plasma target concentration of 4 to 6 μg/mL, or sevoflurane initially started at 8%. Anesthesia was maintained with target-controlled infusion of propofol (2-4 μg/mL) or sevoflurane (1.5%-2.5%). The primary end point was postoperative liver injury assessed by peak values of liver transaminases. Transaminase levels peaked between the first and the third postoperative day. Peak alanine aminotransferase was 504 and 571 U/L in the sevoflurane group and the propofol group, respectively. Peak aspartate aminotransferase was 435 U/L after sevoflurane and 581 U/L in the propofol group. There were no significant differences in peak alanine aminotransferase or peak aspartate aminotransferase between groups. Other liver function tests including bilirubin and alkaline phosphatase, and peak values of white blood cell counts and creatinine, were also not different between groups. Sevoflurane and propofol anesthetics resulted in similar patterns of liver function tests after hepatectomy with inflow occlusion. These data suggest that the 2 anesthetics are equivalent in this clinical context.

Probabilistic peak detection for first-order chromatographic data.

PubMed

Lopatka, M; Vivó-Truyols, G; Sjerps, M J

2014-03-19

We present a novel algorithm for probabilistic peak detection in first-order chromatographic data. Unlike conventional methods that deliver a binary answer pertaining to the expected presence or absence of a chromatographic peak, our method calculates the probability of a point being affected by such a peak. The algorithm makes use of chromatographic information (i.e. the expected width of a single peak and the standard deviation of baseline noise). As prior information of the existence of a peak in a chromatographic run, we make use of the statistical overlap theory. We formulate an exhaustive set of mutually exclusive hypotheses concerning presence or absence of different peak configurations. These models are evaluated by fitting a segment of chromatographic data by least-squares. The evaluation of these competing hypotheses can be performed as a Bayesian inferential task. We outline the potential advantages of adopting this approach for peak detection and provide several examples of both improved performance and increased flexibility afforded by our approach. Copyright © 2014 Elsevier B.V. All rights reserved.

Simulation of double stage hall thruster with double-peaked magnetic field

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Li, Peng; Sun, Hezhi; Wei, Liqiu; Xu, Yu; Peng, Wuji; Su, Hongbo; Li, Hong; Yu, Daren

2017-07-01

This study adopts double permanent magnetic rings and four permanent magnetic rings to form two symmetrical magnetic peaks and two asymmetrical magnetic peaks in the channel of a Hall thruster, and uses a 2D-3V PIC-MCC model to analyze the influence of magnetic strength on the discharge characteristic and performance of Hall thrusters with an intermediate electrode and double-peaked magnetic field. As opposed to the two symmetrical magnetic peaks formed by double permanent magnetic rings, increasing the magnetic peak value deep within the channel can cause propellant ionization to occur; with the increase in the magnetic peak deep in the channel, the propellant utilization, thrust, and anode efficiency of the thruster are significantly improved. Double-peaked magnetic field can realize separate control of ionization and acceleration in a Hall thruster, and provide technical means for further improving thruster performance. Contribution to the Topical Issue "Physics of Ion Beam Sources", edited by Holger Kersten and Horst Neumann.

Aeroplastic, New Composite Materials with Reduced Heat Transfer and Increased Flame Retardancy

NASA Technical Reports Server (NTRS)

Williams, Martha K.; Smith, Trent M.; Nichols, James D.; Roberson, Luke B.; Tate, Lanetra C.

2015-01-01

A new composite system formulated using commodity grade and engineered grade polymers. The composites can be fabricated into fibers, molded, or otherwise processed into useable articles. Use of this technology reduces the thermal conductivity and peak heat releases rates of the base polymer between 20%-50% while maintaining or enhancing the mechanical properties..

Effects of Caffeine on Countermovement-Jump Performance Variables in Elite Male Volleyball Players.

PubMed

Zbinden-Foncea, Hermann; Rada, Isabel; Gomez, Jesus; Kokaly, Marco; Stellingwerff, Trent; Deldicque, Louise; Peñailillo, Luis

2018-02-01

To examine the effects of a moderate dose of caffeine in elite male volleyball players on countermovement-jump (CMJ) performance, as well as temporal concentric- and eccentric-phase effects. Ten elite male volleyball players took part in 2 experimental days via a randomized crossover trial 1 wk apart in which they ingested either 5 mg/kg of caffeine or a placebo in double-blind fashion. Heart rate and blood pressure were measured at rest and 60 min postingestion. Afterward, subjects also performed 3 CMJ trials 60 min postingestion, of which the average was used for further analysis. They filled out a questionnaire on possible side effects 24 h posttrial. Caffeine intake, compared with placebo, increased CMJ peak concentric force (6.5% ± 6.4%; P = .01), peak power (16.2% ± 8.3%; P < .01), flight time (5.3% ± 3.4%; P < .01), velocity at peak power (10.6% ± 8.0%; P < .01), peak displacement (10.8% ± 6.5%; P < .01), peak velocity (12.6% ± 7.4%; P < .01), peak acceleration (13.5% ± 8.5%; P < .01), and the force developed at peak power (6.0% ± 4.0%; P < .01) and reduced the time between peak power and peak force (16.7% ± 21.6%, P = .04). Caffeine increased diastolic blood pressure by 13.0% ± 8.9% (P < .05), whereas no adverse side effects were found. The ingestion of 5 mg/kg of anhydrous caffeine improves overall CMJ performance without inducing side effects.

Peak leg muscle power, peak VO2 and its correlates with physical activity in 57 to 70-year-old women.

PubMed

Boussuge, P-Y; Rance, M; Bedu, M; Duche, P; Praagh, E Van

2006-01-01

The two aims of this study were first to measure short-term muscle power (STMP) by means of a cycling force-velocity test (cycling peak power: CPP) and a vertical jump test (jumping peak performance: JPP) and second, to examine the relationships between physical activity (PA) level, peak oxygen uptake (peak VO2) and STMP in healthy elderly women. Twenty-three independent community-dwelling elderly women (mean age: 64+/-4.4) performed on separate days, a peak oxygen uptake test on cycle ergometer, a cycling force-velocity test and a vertical jump test. A questionnaire (QUANTAP) was used to assess lifespan exercise habits. Four indices expressed in kJ day(-1) kg(-1) were calculated. Two indices represented average past PA level: 1/quantity of habitual physical activity (QHPA), 2/quantity of sports activities (QSA). Two indices represented the actual PA level: 3/actual quantity of habitual physical activity (AQHPA), 4/actual quantity of sports activities (AQSA). CPP (6.3+/-1.2 W kg(-1)) was closely correlated to JPP (14.8+/-3.4 cm) (r=0.80, P<0.001). AQHPA and AQSA were only positively associated with peak VO2 (ml min(-1) kg(-1)) (r=0.49; r=0.50, P<0.05, respectively). Past PA level was not related to fitness measurements. Results show that in this population: (1) jumping peak performance was closely related to CPP measured in the laboratory; (2) the cardio-respiratory fitness was related to the actual habitual physical activity level; (3) only age and anthropometric variables explained the actual performances in multivariate analysis.

Factors affecting performance in an ultraendurance triathlon.

PubMed

Laursen, P B; Rhodes, E C

2001-01-01

In the recent past, researchers have found many key physiological variables that correlate highly with endurance performance. These include maximal oxygen uptake (VO2max), anaerobic threshold (AT), economy of motion and the fractional utilisation of oxygen uptake (VO2). However, beyond typical endurance events such as the marathon, termed 'ultraendurance' (i.e. >4 hours), performance becomes harder to predict. The ultraendurance triathlon (UET) is a 3-sport event consisting of a 3.8 km swim and a 180 km cycle, followed by a 42.2 km marathon run. It has been hypothesised that these triathletes ride at approximately their ventilatory threshold (Tvent) during the UET cycling phase. However, laboratory assessments of cycling time to exhaustion at a subject's AT peak at 255 minutes. This suggests that the AT is too great an intensity to be maintained during a UET, and that other factors cause detriments in prolonged performance. Potential defeating factors include the provision of fuels and fluids due to finite gastric emptying rates causing changes in substrate utilisation, as well as fluid and electrolyte imbalances. Thus, an optimum ultraendurance intensity that may be relative to the AT intensity is needed to establish ultraendurance intensity guidelines. This optimal UET intensity could be referred to as the ultraendurance threshold.

Effects of ageing on orofacial fine force control and its relationship with parallel change in sensory perception.

PubMed

Etter, Nicole M; Mckeon, Patrick O; Dressler, Emily V; Andreatta, Richard D

2017-05-03

Current theoretical models suggest the importance of a bidirectional relationship between sensation and production in the vocal tract to maintain lifelong speech skills. The purpose of this study was to assess age-related changes in orofacial skilled force production and to begin defining the orofacial perception-action relationship in healthy adults. Low-level orofacial force control measures (reaction time, rise time, peak force, mean hold force (N) and force hold SD) were collected from 60 adults (19-84 years). Non-parametric Kruskal Wallis tests were performed to identify statistical differences between force and group demographics. Non-parametric Spearman's rank correlations were completed to compare force measures against previously published sensory data from the same cohort of participants. Significant group differences in force control were found for age, sex, speech usage and smoking status. Significant correlational relationships were identified between labial vibrotactile thresholds and several low-level force control measures collected during step and ramp-and-hold conditions. These findings demonstrate age-related alterations in orofacial force production. Furthermore, correlational analysis suggests as vibrotactile detection thresholds increase, the ability to maintain low-level force control accuracy decreases. Possible clinical applications and treatment consequences of these findings for speech disorders in the ageing population are provided.

A Comparison between young and old adults in their ability to rapidly sidestep during gait when attention is divided.

PubMed

Cho, Chiung-Yu; Gilchrist, Louise; White, Scott

2008-01-01

The incidence of falls among older adults is high and the risk factors are often complex in nature. Considerable research has been done in the area of age-related changes of balance in an attempt to better understand the increased risk of falls. Studies of cognitive changes, however, suggest that the elderly are less able to divide their attention between two or more activities. This inability to divide attention could explain the increased risks of falls in the elderly. To investigate the effects of divided attention, age and prior knowledge of movement path, on kinetic measures and the position of the sacral marker relative to the center of pressure (COP) when individuals perform a rapid sidestep during walking. 32 young and 32 old adults participated in this study. Subjects walked and took a sidestep without interrupting forward progression. An arithmetic task was performed during half of the walking trials with the sidestep direction preplanned or unknown. Peak lateral ground reaction force, mean distance between COP and sacrum, walking velocity, performance speed and accuracy of the cognitive task were measured. Both groups significantly decreased their mediolateral distance between the sacral marker and the COP in the dual-task trials (p = 0.04). Both groups significantly decreased their walking speed in the dual-task trials (p < 0.0001). Prior knowledge of the sidestep direction significantly affected the peak lateral ground reaction force and the sacral marker to COP distance but the differences were age-dependent. Young adults had a larger value in the unknown condition than in the preplanned condition (p < 0.0001). For the cognitive task, both groups decreased their performance speed (p < 0.0001) but maintained their performance accuracy as compared to the baseline data (p > 0.05). Our results revealed that old adults tended to be conservative, when facing the dual-task trials or unknown test condition. The fact that the older adults in the current study did not perform similarly to the younger adults suggests that they might have a fear of fall when facing a challenging balance task. (c) 2008 S. Karger AG, Basel.

The effect of fatigue and training status on firefighter performance.

PubMed

Dennison, Katie J; Mullineaux, David R; Yates, James W; Abel, Mark G

2012-04-01

Firefighting is a strenuous occupation that requires optimal levels of physical fitness. The National Fire Protection Association suggests that firefighters should be allowed to exercise on duty to maintain adequate fitness levels. However, no research has addressed the effect of exercise-induced fatigue on subsequent fire ground performance. Therefore, the primary purpose of this study was to determine the effect that a single exercise session had on the performance of a simulated fire ground test (SFGT). Secondarily, this study sought to compare the effect of physical training status (i.e., trained vs. untrained firefighters) on the performance of an SFGT. Twelve trained (age: 31.8 ± 6.9 years; body mass index [BMI]: 27.7 ± 3.3 kg·m(-2); VO2peak: 45.6 ± 3.3 ml·kg(-1)·min(-1)) and 37 untrained (age: 31.0 ± 9.0 years; BMI: 31.3 ± 5.2 kg·m(-2); VO2peak: 40.2 ± 5.2 ml·kg(-1)·min(-1)) male career firefighters performed a baseline SFGT. The trained firefighters performed a second SFGT after an exercise session. Time to complete the SFGT, heart rate, and blood lactate were compared between baseline and exercise SFGT (EX-SFGT) conditions. In the trained firefighters, time to complete the SFGT (9.6% increase; p = 0.002) and heart rate (4.1% increase; p = 0.032) were greater during the EX-SFGT compared with baseline, with no difference in post-SFGT blood lactate (p = 0.841). The EX-SFGT time of the trained firefighters was faster than approximately 70% of the untrained firefighters' baseline SFGT time. In addition, the baseline SFGT time of the trained firefighters was faster than 81% of the untrained firefighters. This study demonstrated that on-duty exercise training reduced the work efficiency in firefighters. However, adaptations obtained through regular on-duty exercise training may limit decrements in work efficiency because of acute exercise fatigue and allow for superior work efficiency compared with not participating in a training program.

Excercise Within LBNP as an Artificial Gravity Countermeasure

NASA Technical Reports Server (NTRS)

Hargens, A. R.; Watenpaugh, D. E.; Lee, S. M. C.; Meyer, R. S.; Macias, B.; Tanaka, K.; Kimura, S.; Steinbach, G.; Groppo, E.; Khalili, N.;

Short-term Periodization Models: Effects on Strength and Speed-strength Performance.

PubMed

Hartmann, Hagen; Wirth, Klaus; Keiner, Michael; Mickel, Christoph; Sander, Andre; Szilvas, Elena

2015-10-01

Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12-15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In high-performance sports, high-repetition strength training (>15) should be avoided because it does not provide an adequate training stimulus for gains in muscle cross-sectional area and strength performance. High-volume circuit strength training performed over 2 years negatively affected the development of the power output and maximal strength of the upper extremities in professional rugby players. Indeed, meta-analyses and results with weightlifters, American Football players, and throwers confirm the necessity of the habitual use of ≥80% 1 RM: (1) to improve maximal strength during the off-season and in-season in American Football, (2) to reach peak performance in maximal strength and vertical jump power during tapering in track-and-field, and (3) to produce hypertrophy and strength improvements in advanced athletes. The integration and extent of hypertrophy strength training in in-season conditioning depend on the duration of the contest period, the frequency of the contests, and the proportion of the conditioning program. Based on the literature, 72 h between hypertrophy strength training and strength-power training should be provided to allow for adequate regeneration times and therefore maximal stimulus intensities in training. This conclusion is only valid if the muscle is not trained otherwise during this regeneration phase. Thus, rotating hypertrophy and strength-power sessions in a microcycle during the season is a viable option. Comparative studies in competitive athletes who integrated strength training during pre-season conditioning confirm a tendency for gains in explosive strength and statistically significant improvements in medicine ball throw through SPP but not through daily undulating periodization. These findings indicate that to maximize the speed-strength in the short term (peaking), elite athletes should perform strength-power training twice per week. It is possible to perform a single strength-power session with the method of maximum explosive strength actions moving high-weight loads (90% 1 repetition maximum [RM]) at least 1-2 days before competition because of the shorter regeneration times and potentiation effects. Compared with ballistic strength training (30% 1 RM), this method has been shown to provide statistically superior gains in maximal strength, peak power, impulse size, and explosive strength during tapering in track-and-field throwers. The speed-strength performance in drop jumps of strength-trained subjects showed potentiation effects 48-148 h after a single strength-power training session. Regarding neuromuscular performance, plyometric exercises can even be performed after strength-power training on the same day if a minimum rest period of 3 h is provided.

Central and peripheral cardiovascular responses to electrically induced and voluntary leg exercise

NASA Technical Reports Server (NTRS)

Saltin, B.; Strange, S.; Bangsbo, J.; Kim, C. K.; Duvoisin, M.; Hargens, A.; Gollnick, P. D.

1990-01-01

With long missions in space countermeasures have to be used to secure safe operations in space and a safe return to Earth. Exercises of various forms have been used, but the question has arisen whether electrically induced contractions of muscle especially sensitive to weightlessness and crucial for man's performance would aid in maintaining their optimal function. The physiological responses both to short term and prolonged dynamic exercise performed either voluntarily or induced by electrical stimulation were considered. The local and systemic circulatory responses were similar for the voluntary and electrically induced contractions. The metabolic response was slightly more pronounced with electrical stimulation. This could be a reflection of not only slow twitch (type 1) but also fast twitch (type 2) fibers being recruited when the contractions were induced electrically. Intramuscular pressure recordings indicated that the dominant fraction of the muscle group was engaged regardless of mode of activation. Some 70 percent of the short term peak voluntary exercise capacity could be attained with electrical stimulation. Thus, electrically induced contractions of specific muscle groups should indeed be considered as an efficient countermeasure.

Bioanode as a limiting factor to biocathode performance in microbial electrolysis cells.

PubMed

Lim, Swee Su; Yu, Eileen Hao; Daud, Wan Ramli Wan; Kim, Byung Hong; Scott, Keith

2017-08-01

The bioanode is important for a microbial electrolysis cell (MEC) and its robustness to maintain its catalytic activity affects the performance of the whole system. Bioanodes enriched at a potential of +0.2V (vs. standard hydrogen electrode) were able to sustain their oxidation activity when the anode potential was varied from -0.3 up to +1.0V. Chronoamperometric test revealed that the bioanode produced peak current density of 0.36A/m 2 and 0.37A/m 2 at applied potential 0 and +0.6V, respectively. Meanwhile hydrogen production at the biocathode was proportional to the applied potential, in the range from -0.5 to -1.0V. The highest production rate was 7.4L H 2 /(m 2 cathode area)/day at -1.0V cathode potential. A limited current output at the bioanode could halt the biocathode capability to generate hydrogen. Therefore maximum applied potential that can be applied to the biocathode was calculated as -0.84V without overloading the bioanode. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Climate-related variation in plant peak biomass and growth phenology across Pacific Northwest tidal marshes

NASA Astrophysics Data System (ADS)

Buffington, Kevin J.; Dugger, Bruce D.; Thorne, Karen M.

2018-03-01

The interannual variability of tidal marsh plant phenology is largely unknown and may have important ecological consequences. Marsh plants are critical to the biogeomorphic feedback processes that build estuarine soils, maintain marsh elevation relative to sea level, and sequester carbon. We calculated Tasseled Cap Greenness, a metric of plant biomass, using remotely sensed data available in the Landsat archive to assess how recent climate variation has affected biomass production and plant phenology across three maritime tidal marshes in the Pacific Northwest of the United States. First, we used clipped vegetation plots at one of our sites to confirm that tasseled cap greenness provided a useful measure of aboveground biomass (r2 = 0.72). We then used multiple measures of biomass each growing season over 20-25 years per study site and developed models to test how peak biomass and the date of peak biomass varied with 94 climate and sea-level metrics using generalized linear models and Akaike Information Criterion (AIC) model selection. Peak biomass was positively related to total annual precipitation, while the best predictor for date of peak biomass was average growing season temperature, with the peak 7.2 days earlier per degree C. Our study provides insight into how plants in maritime tidal marshes respond to interannual climate variation and demonstrates the utility of time-series remote sensing data to assess ecological responses to climate stressors.

Influence of sleep and meal schedules on performance peaks in competitive sprinters.

PubMed

Javierre, C; Calvo, M; Díez, A; Garrido, E; Segura, R; Ventura, J L

1996-08-01

The influence of sleep and meal schedules on performance in short distance running was assessed in a group of 8 national-class competition male sprinters. They were tested on Saturdays for five consecutive weeks. On each testing day, the performance time for an 80 m sprint was registered on eight different occasions during days 1 and 4, on 9 occasions on days 2 and 5, and on 7 occasions on day 3. On control days (days 1 and 4) performance gradually improved during the morning up to 13:00 h, decreased at 15:00 h, and again improved thereafter, with a maximum peak performance at 19:00 h. On day 2, in which sleep/wake cycles and meal-times were advanced for two hours, and on day 3, in which timetables were delayed for two hours, maximum peak performance was observed at 17:00 h and 21:00 h, respectively. At the time of maximum peak performance on both days a statistically significant improvement was observed as compared with the control day (day 2, p < 0.01; day 3, p = 0.001). On day 5, in which only the sleep/wake cycle was advanced for two hours, performance in the afternoon and evening was similar to that recorded on days 1 and 4. We observed that easy manipulation of sleep and meal schedules would allow competitive sprinters to synchronize peak power output with the time of the athletic event, increasing the chances for improvement in performance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Alex

We summarize the current state of a concept for muon acceleration aimed at a future Neutrino Factory and extendable to Higgs Factory. The main thrust of these studies was to reduce the overall cost while maintaining performance by exploring the interplay between the complexity of the cooling systems and the acceptance of the accelerator complex. To ensure adequate survival for the short-lived muons, acceleration must occur at high average gradient. The need for large transverse and longitudinal acceptances drives the design of the acceleration system to an initially low RF frequency, e.g., 325 MHz, which is then increased to 650more » MHz as the transverse size shrinks with increasing energy. High-gradient normal conducting RF cavities at these frequencies require extremely high peak-power RF sources. Hence superconducting RF (SRF) cavities are chosen. We consider an SRF-efficient design based on a multi-pass (4.5) ?dogbone? RLA, extendable to multi-pass FFAG-like arcs.« less

Energy-Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Withers, Jr., Charles R.

2016-12-01

In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split onmore » seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.« less

Building America Case Study: Energy Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates, Cocoa, Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-01-01

In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split onmore » seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.« less

Supplemental optical specifications for imaging systems: parameters of phase gradient

NASA Astrophysics Data System (ADS)

Xuan, Bin; Li, Jun-Feng; Wang, Peng; Chen, Xiao-Ping; Song, Shu-Mei; Xie, Jing-Jiang

2009-12-01

Specifications of phase error, peak to valley (PV), and root mean square (rms) are not able to represent the properties of a wavefront reasonably because of their irresponsibility for spatial frequencies. Power spectral density is a parameter that is especially effective to indicate the frequency regime. However, it seems not convenient for opticians to implement. Parameters of phase gradient, PV gradient, and rms gradient are most correlated with a point-spread function of an imaging system, and they can provide clear instruction of manufacture. The algorithms of gradient parameters have been modified in order to represent the image quality better. In order to demonstrate the analyses, an experimental spherical mirror has been worked out. It is clear that imaging performances can be maintained while manufacture difficulties are decreased when a reasonable trade-off between specifications of phase error and phase gradient is made.

Improvements in ion reflux: An electrodialytic eluent generation and suppression device for ion chromatography.

PubMed

Elkin, Kyle; Riviello, John; Small, Hamish

2015-07-17

This work describes a membrane based electrodialytic ion reflux device (IRD), which uses water as the pumped phase and integrates isocratic and gradient eluent generation and suppression. The current design incorporates several ion exchange membranes to create discrete chambers for suppression and eluent generation, while isolating the electrodes from the analytical stream. A small volume of recycled water can be used as the pumped phase while continuously refluxing the eluent ions. This current design permits electronically controlled eluent generation of at least 16.4μeq KOHmin(-1), while maintaining low suppressed background conductivity (<0.5μS/cm). The device was operated in gradient or isocratic mode continuously for up to 6 weeks. During this period, over 500 gradient and isocratic injections were performed, showing peak retention time precision below 1.5% RSD. Published by Elsevier B.V.

Pneumothorax as a complication of lung volume recruitment.

PubMed

Westermann, Erik J A; Jans, Maurice; Gaytant, Michael A; Bach, John R; Kampelmacher, Mike J

2013-01-01

Lung volume recruitment involves deep inflation techniques to achieve maximum insufflation capacity in patients with respiratory muscle weakness, in order to increase peak cough flow, thus helping to maintain airway patency and improve ventilation. One of these techniques is air stacking, in which a manual resuscitator is used in order to inflate the lungs. Although intrathoracic pressures can rise considerably, there have been no reports of respiratory complications due to air stacking. However, reaching maximum insufflation capacity is not recommended in patients with known structural abnormalities of the lungs or chronic obstructive airway disease. We report the case of a 72-year-old woman who had poliomyelitis as a child, developed torsion scoliosis and post-polio syndrome, and had periodic but infrequent asthma attacks. After performing air stacking for 3 years, the patient suddenly developed a pneumothorax, indicating that this technique should be used with caution or not at all in patients with a known pulmonary pathology.

Acute effects of heavy-load squats on consecutive squat jump performance.

PubMed

Weber, Kurt R; Brown, Lee E; Coburn, Jared W; Zinder, Steven M

2008-05-01

Postactivation potentiation (PAP) and complex training have generated interest within the strength and conditioning community in recent years, but much of the research to date has produced confounding results. The purpose of this study was to observe the acute effects of a heavy-load back squat [85% 1 repetition maximum (1RM)] condition on consecutive squat jump performance. Twelve in-season Division I male track-and-field athletes participated in two randomized testing conditions: a five-repetition back squat at 85% 1RM (BS) and a five-repetition squat jump (SJ). The BS condition consisted of seven consecutive squat jumps (BS-PRE), followed by five repetitions of the BS at 85% 1RM, followed by another set of seven consecutive squat jumps (BS-POST). The SJ condition was exactly the same as the BS condition except that five consecutive SJs replaced the five BSs, with 3 minutes' rest between each set. BS-PRE, BS-POST, SJ-PRE, and SJ-POST were analyzed and compared for mean and peak jump height, as well as mean and peak ground reaction force (GRF). The BS condition's mean and peak jump height and peak GRF increased 5.8% +/- 4.8%, 4.7% +/- 4.8%, and 4.6% +/- 7.4%, respectively, whereas the SJ condition's mean and peak jump height and peak GRF decreased 2.7% +/- 5.0%, 4.0% +/- 4.9%, and 1.3% +/- 7.5%, respectively. The results indicate that performing a heavy-load back squat before a set of consecutive SJs may enhance acute performance in average and peak jump height, as well as peak GRF.

Opportunities for Joint Water–Energy Management: Sensitivity of the 2010 Western U.S. Electricity Grid Operations to Climate Oscillations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voisin, N.; Kintner-Meyer, M.; Wu, D.

The 2016 SECURE Water Act report’s natural water availability benchmark, combined with the 2010 level of water demand from an integrated assessment model, is used as input to drive a large-scale water management model. The regulated flow at hydropower plants and thermoelectric plants in the Western U.S. electricity grid (WECC) is translated into potential hydropower generation and generation capacity constraints. The impact on reliability (unserved energy, reserve margin) and cost (production cost, carbon emissions) of water constraints on 2010-level WECC power system operations is assessed using an electricity production cost model (PCM). Use of the PCM reveals the changes inmore » generation dispatch that reflect the inter-regional interdependencies in water-constrained generation and the ability to use other generation resources to meet all electricity loads in the WECC. August grid operational benchmarks show a range of sensitivity in production cost (-8 to +11%) and carbon emissions (-7 to 11%). The reference reserve margin threshold of 15% above peak load is maintained in the scenarios analyzed, but in 5 out of 55 years unserved energy is observed when normal operations are maintained. There is 1 chance in 10 that a year will demonstrate unserved energy in August, which defines the system’s historical performance threshold to support impact, vulnerability, and adaptation analysis. For seasonal and longer term planning, i.e., multi-year drought, we demonstrate how the Water Scarcity Grid Impact Factor and climate oscillations (ENSO, PDO) can be used to plan for joint water-electricity management to maintain grid reliability.« less

Treadmill Exercise Within LBNP as an Integrated Coutermeasure to Microgravity

NASA Technical Reports Server (NTRS)

Lee, Stuart; Hargens, A. R.; Schneider, S. M.; Watenpaugh, D. E.

2010-01-01

An integrated exercise countermeasure for microgravity is needed to protect multiple physiologic systems and save crew time. Such a countermeasure should protect orthostatic tolerance, upright ambulatory capability (including sprinting), aerobic capacity, muscle strength/endurance, and other physiologic parameters relevant to human performance. We developed a novel physiologic countermeasure, treadmill exercise within LBNP, for preventing cardiovascular and musculoskeletal deconditioning associated with prolonged bed rest and spaceflight. We evaluated 40 min of daily LBNP treadmill exercise by a battery of physiologic parameters relevant to maintaining exercise performance and health of both women and men during bed-rest (simulated microgravity) studies lasting from 5 to 60 days. For 30 day studies, we employed identical twins with one twin as the control and the other twin as the exerciser to improve comparative power. During the WISE 60-day HDT study, the treadmill exercise within LBNP was performed 3-4 days each week and resistive exercise was performed 2-3 days each week. Our treadmill within LBNP protocol maintained plasma volume and sprint speed (30 day HDT bed-rest studies of identical twins), orthostatic tolerance to a degree, upright exercise capacity, muscle strength and endurance, and some bone parameters during 30 day (twin studies) and 60 day (WISE-2005) bed-rest simulations of microgravity. When combining treadmill exercise within LBNP and resistive exercise (WISE), cardiac mass increased significantly in the exercise (EX) group during bed rest relative to controls (CON). Upright peak VO2, and knee extensor strength and endurance decreased significantly in CON subjects; but these parameters were preserved in the EX group. In the 60 day WISE study, each LBNP exercise session was followed immediately by 10 minutes of static LBNP, and the last such session occurred three days before the end of bed rest. Still, orthostatic tolerance was better maintained in the EX group than in the CON group. Therefore, these collective peer-reviewed results document that our treadmill exercise within LBNP countermeasure safely and efficiently protects multiple physiologic systems in women and men during bed-rest studies of up to 60 days. Supported by NASA grants NNJ04HF71G and NAG 9-1425, NIH grant GCRC M01 RR00827 and by WISE support from ESA, NASA, CSA, and CNES.

Effect of Permissive Dehydration on Induction and Decay of Heat Acclimation, and Temperate Exercise Performance

PubMed Central

Neal, Rebecca A.; Massey, Heather C.; Tipton, Michael J.; Young, John S.; Corbett, Jo

2016-01-01

Purpose: It has been suggested that dehydration is an independent stimulus for heat acclimation (HA), possibly through influencing fluid-regulation mechanisms and increasing plasma volume (PV) expansion. There is also some evidence that HA may be ergogenic in temperate conditions and that this may be linked to PV expansion. We investigated: (i) the influence of dehydration on the time-course of acquisition and decay of HA; (ii) whether dehydration augmented any ergogenic benefits in temperate conditions, particularly those related to PV expansion. Methods: Eight males [VO2max: 56.9(7.2) mL·kg−1·min−1] undertook two HA programmes (balanced cross-over design), once drinking to maintain euhydration (HAEu) and once with restricted fluid-intake (HADe). Days 1, 6, 11, and 18 were 60 min exercise-heat stress tests [HST (40°C; 50% RH)], days 2–5 and 7–10 were 90 min, isothermal-strain (Tre ~ 38.5°C), exercise-heat sessions. Performance parameters [VO2max, lactate threshold, efficiency, peak power output (PPO)] were determined pre and post HA by graded exercise test (22°C; 55%RH). Results: During isothermal-strain sessions hypohydration was achieved in HADe and euhydration maintained in HAEu [average body mass loss −2.71(0.82)% vs. −0.56(0.73)%, P < 0.001], but aldosterone concentration, power output, and cardiovascular strain were unaffected by dehydration. HA was evident on day 6 {reduced end-exercise Tre [−0.30(0.27)°C] and exercise heart rate [−12(15) beats.min−1], increased PV [+7.2(6.4)%] and sweat-loss [+0.25(0.22) L.h−1], P < 0.05} with some further adaptations on day 11 {further reduced end-exercise Tre [−0.25(0.19)°C] and exercise heart rate [−3(9) beats.min−1], P < 0.05}. These adaptations were not notably affected by dehydration and were generally maintained 7-days post HA. Performance parameters were unchanged, apart from increased PPO (+16(20) W, irrespective of condition). Conclusions: When thermal-strain is matched, permissive dehydration which induces a mild, transient, hypohydration does not affect the acquisition and decay of HA, or endurance performance parameters. Irrespective of hydration, trained individuals require >5 days to optimize HA. PMID:27932993

Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings

NASA Astrophysics Data System (ADS)

Kamal, Rajeev

Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times. Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings: 1. Use of gas heat pumps in place of electric heat pumps, and 2. Shifting demand for air conditioning from peak to off-peak by thermal energy storage in chilled water and ice. The first part of this study evaluates the field performance of gas engine-driven heat pumps (GEHP) tested in a commercial building in Florida. Four GEHP units of 8 Tons of Refrigeration (TR) capacity each providing air-conditioning to seven thermal zones in a commercial building, were instrumented for measuring their performance. The operation of these GEHPs was recorded for ten months, analyzed and compared with prior results reported in the literature. The instantaneous COPunit of these systems varied from 0.1 to 1.4 during typical summer week operation. The COP was low because the gas engines for the heat pumps were being used for loads that were much lower than design capacity which resulted in much lower efficiencies than expected. The performance of equivalent electric heat pump was simulated from a building energy model developed to mimic the measured building loads. An economic comparison of GEHPs and conventional electrical heat pumps was done based on the measured and simulated results. The average performance of the GEHP units was estimated to lie between those of EER-9.2 and EER-11.8 systems. The performance of GEHP systems suffers due to lower efficiency at part load operation. The study highlighted the need for optimum system sizing for GEHP/HVAC systems to meet the building load to obtain better performance in buildings. The second part of this study focusses on using chilled water or ice as thermal energy storage for shifting the air conditioning load from peak to off-peak in a commercial building. Thermal energy storage can play a very important role in providing demand-side management for diversifying the utility demand from buildings. Model of a large commercial office building is developed with thermal storage for cooling for peak power shifting. Three variations of the model were developed and analyzed for their performance with 1) ice storage, 2) chilled water storage with mixed storage tank and 3) chilled water storage with stratified tank, using EnergyPlus 8.5 software developed by the US Department of Energy. Operation strategy with tactical control to incorporate peak power schedule was developed using energy management system (EMS). The modeled HVAC system was optimized for minimum cost with the optimal storage capacity and chiller size using JEPlus. Based on the simulation, an optimal storage capacity of 40-45 GJ was estimated for the large office building model along with 40% smaller chiller capacity resulting in higher chiller part-load performance. Additionally, the auxiliary system like pump and condenser were also optimized to smaller capacities and thus resulting in less power demand during operation. The overall annual saving potential was found in the range of 7-10% for cooling electricity use resulting in 10-17% reduction in costs to the consumer. A possible annual peak shifting of 25-78% was found from the simulation results after comparing with the reference models. Adopting TES in commercial buildings and achieving 25% peak shifting could result in a reduction in peak summer demand of 1398 MW in Tampa.

Replication and shedding kinetics of infectious hematopoietic necrosis virus in juvenile rainbow trout

USGS Publications Warehouse

Wargo, Andrew R.; Scott, Robert J.; Kerr, Benjamin; Kurath, Gael

2017-01-01

Viral replication and shedding are key components of transmission and fitness, the kinetics of which are heavily dependent on virus, host, and environmental factors. To date, no studies have quantified the shedding kinetics of infectious hematopoietic necrosis virus (IHNV) in rainbow trout (Oncorhynchus mykiss), or how they are associated with replication, making it difficult to ascertain the transmission dynamics of this pathogen of high agricultural and conservation importance. Here, the replication and shedding kinetics of two M genogroup IHNV genotypes were examined in their naturally co-evolved rainbow trout host. Within host virus replication began rapidly, approaching maximum values by day 3 post-infection, after which viral load was maintained or gradually dropped through day 7. Host innate immune response measured as stimulation of Mx-1 gene expression generally followed within host viral loads. Shedding also began very quickly and peaked within 2 days, defining a generally uniform early peak period of shedding from 1 to 4 days after exposure to virus. This was followed by a post-peak period where shedding declined, such that the majority of fish were no longer shedding by day 12 post-infection. Despite similar kinetics, the average shedding rate over the course of infection was significantly lower in mixed compared to single genotype infections, suggesting a competition effect, however, this did not significantly impact the total amount of virus shed. The data also indicated that the duration of shedding, rather than peak amount of virus shed, was correlated with fish mortality. Generally, the majority of virus produced during infection appeared to be shed into the environment rather than maintained in the host, although there was more retention of within host virus during the post-peak period. Viral virulence was correlated with shedding, such that the more virulent of the two genotypes shed more total virus. This fundamental understanding of IHNV shedding kinetics and variation at the individual fish level could assist with management decisions about how to respond to disease outbreaks when they occur.

Replication and shedding kinetics of infectious hematopoietic necrosis virus in juvenile rainbow trout.

PubMed

Wargo, Andrew R; Scott, Robert J; Kerr, Benjamin; Kurath, Gael

2017-01-02

Viral replication and shedding are key components of transmission and fitness, the kinetics of which are heavily dependent on virus, host, and environmental factors. To date, no studies have quantified the shedding kinetics of infectious hematopoietic necrosis virus (IHNV) in rainbow trout (Oncorhynchus mykiss), or how they are associated with replication, making it difficult to ascertain the transmission dynamics of this pathogen of high agricultural and conservation importance. Here, the replication and shedding kinetics of two M genogroup IHNV genotypes were examined in their naturally co-evolved rainbow trout host. Within host virus replication began rapidly, approaching maximum values by day 3 post-infection, after which viral load was maintained or gradually dropped through day 7. Host innate immune response measured as stimulation of Mx-1 gene expression generally followed within host viral loads. Shedding also began very quickly and peaked within 2days, defining a generally uniform early peak period of shedding from 1 to 4days after exposure to virus. This was followed by a post-peak period where shedding declined, such that the majority of fish were no longer shedding by day 12 post-infection. Despite similar kinetics, the average shedding rate over the course of infection was significantly lower in mixed compared to single genotype infections, suggesting a competition effect, however, this did not significantly impact the total amount of virus shed. The data also indicated that the duration of shedding, rather than peak amount of virus shed, was correlated with fish mortality. Generally, the majority of virus produced during infection appeared to be shed into the environment rather than maintained in the host, although there was more retention of within host virus during the post-peak period. Viral virulence was correlated with shedding, such that the more virulent of the two genotypes shed more total virus. This fundamental understanding of IHNV shedding kinetics and variation at the individual fish level could assist with management decisions about how to respond to disease outbreaks when they occur. Copyright © 2016 Elsevier B.V. All rights reserved.

Replication and shedding kinetics of infectious hematopoietic necrosis virus in juvenile rainbow trout

PubMed Central

Wargo, Andrew R.; Scott, Robert J.; Kerr, Benjamin; Kurath, Gael

2016-01-01

Viral replication and shedding are key components of transmission and fitness, the kinetics of which are heavily dependent on virus, host, and environmental factors. To date, no studies have quantified the shedding kinetics of infectious hematopoietic necrosis virus (IHNV) in rainbow trout (Oncorhynchus mykiss), or how they are associated with replication, making it difficult to ascertain the transmission dynamics of this pathogen of high agricultural and conservation importance. Here, the replication and shedding kinetics of two M genogroup IHNV genotypes were examined in their naturally co-evolved rainbow trout host. Within host virus replication began rapidly, approaching maximum values by day 3 post-infection, after which viral load was maintained or gradually dropped through day 7. Host innate immune response measured as stimulation of Mx-1 gene expression generally followed within host viral loads. Shedding also began very quickly and peaked within 2 days, defining a generally uniform early peak period of shedding from 1 to 4 days after exposure to virus. This was followed by a post-peak period where shedding declined, such that the majority offish were no longer shedding by day 12 post-infection. Despite similar kinetics, the average shedding rate over the course of infection was significantly lower in mixed compared to single genotype infections, suggesting a competition effect, however, this did not significantly impact the total amount of virus shed. The data also indicated that the duration of shedding, rather than peak amount of virus shed, was correlated with fish mortality. Generally, the majority of virus produced during infection appeared to be shed into the environment rather than maintained in the host, although there was more retention of within host virus during the post-peak period. Viral virulence was correlated with shedding, such that the more virulent of the two genotypes shed more total virus. This fundamental understanding of IHNV shedding kinetics and variation at the individual fish level could assist with management decisions about how to respond to disease outbreaks when they occur. PMID:27771253

Linear MALDI-ToF simultaneous spectrum deconvolution and baseline removal.

PubMed

Picaud, Vincent; Giovannelli, Jean-Francois; Truntzer, Caroline; Charrier, Jean-Philippe; Giremus, Audrey; Grangeat, Pierre; Mercier, Catherine

2018-04-05

Thanks to a reasonable cost and simple sample preparation procedure, linear MALDI-ToF spectrometry is a growing technology for clinical microbiology. With appropriate spectrum databases, this technology can be used for early identification of pathogens in body fluids. However, due to the low resolution of linear MALDI-ToF instruments, robust and accurate peak picking remains a challenging task. In this context we propose a new peak extraction algorithm from raw spectrum. With this method the spectrum baseline and spectrum peaks are processed jointly. The approach relies on an additive model constituted by a smooth baseline part plus a sparse peak list convolved with a known peak shape. The model is then fitted under a Gaussian noise model. The proposed method is well suited to process low resolution spectra with important baseline and unresolved peaks. We developed a new peak deconvolution procedure. The paper describes the method derivation and discusses some of its interpretations. The algorithm is then described in a pseudo-code form where the required optimization procedure is detailed. For synthetic data the method is compared to a more conventional approach. The new method reduces artifacts caused by the usual two-steps procedure, baseline removal then peak extraction. Finally some results on real linear MALDI-ToF spectra are provided. We introduced a new method for peak picking, where peak deconvolution and baseline computation are performed jointly. On simulated data we showed that this global approach performs better than a classical one where baseline and peaks are processed sequentially. A dedicated experiment has been conducted on real spectra. In this study a collection of spectra of spiked proteins were acquired and then analyzed. Better performances of the proposed method, in term of accuracy and reproductibility, have been observed and validated by an extended statistical analysis.

DSN 70-meter antenna microwave optics design and performance improvements. Part 2: Comparison with measurements

NASA Technical Reports Server (NTRS)

Bathker, D. A.; Slobin, S. D.

1989-01-01

The measured Deep Space Network (DSN) 70-meter antenna performance at S- and X-bands is compared with the design expectations. A discussion of natural radio-source calibration standards is given. New estimates of DSN 64-meter antenna performance are given, based on improved values of calibration source flux and size correction. A comparison of the 64- and 70-meter performances shows that average S-band peak gain improvement is 1.94 dB, compared with a design expectation of 1.77 dB. At X-band, the average peak gain improvement is 2.12 dB, compared with the (coincidentally similar) design expectation of 1.77 dB. The average measured 70-meter S-band peak gain exceeds the nominal design-expected gain by 0.02 dB; the average measured 70-meter X-band peak gain is 0.14 dB below the nominal design-expected gain.

Simple and conditional visual discrimination with wheel running as reinforcement in rats.

PubMed

Iversen, I H

1998-09-01

Three experiments explored whether access to wheel running is sufficient as reinforcement to establish and maintain simple and conditional visual discriminations in nondeprived rats. In Experiment 1, 2 rats learned to press a lit key to produce access to running; responding was virtually absent when the key was dark, but latencies to respond were longer than for customary food and water reinforcers. Increases in the intertrial interval did not improve the discrimination performance. In Experiment 2, 3 rats acquired a go-left/go-right discrimination with a trial-initiating response and reached an accuracy that exceeded 80%; when two keys showed a steady light, pressing the left key produced access to running whereas pressing the right key produced access to running when both keys showed blinking light. Latencies to respond to the lights shortened when the trial-initiation response was introduced and became much shorter than in Experiment 1. In Experiment 3, 1 rat acquired a conditional discrimination task (matching to sample) with steady versus blinking lights at an accuracy exceeding 80%. A trial-initiation response allowed self-paced trials as in Experiment 2. When the rat was exposed to the task for 19 successive 24-hr periods with access to food and water, the discrimination performance settled in a typical circadian pattern and peak accuracy exceeded 90%. When the trial-initiation response was under extinction, without access to running, the circadian activity pattern determined the time of spontaneous recovery. The experiments demonstrate that wheel-running reinforcement can be used to establish and maintain simple and conditional visual discriminations in nondeprived rats.

Development and application of a validated stability-indicating HPLC method for simultaneous determination of granisetron hydrochloride, benzyl alcohol and their main degradation products in parenteral dosage forms.

PubMed

Hewala, Ismail; El-Fatatre, Hamed; Emam, Ehab; Mubrouk, Mokhtar

2010-06-30

A simple, rapid and sensitive reversed phase high performance liquid chromatographic method using photodiode array detection was developed and validated for the simultaneous determination of granisetron hydrochloride, benzyl alcohol, 1-methyl-1H-indazole-3-carboxylic acid (the main degradation product of granisetron) and benzaldehyde (the main degradation product of benzyl alcohol) in granisetron injections. The separation was achieved on Hypersil BDS C8 (250 mm x 4.6 mm i.d., 5 microm particle diameter) column using a mobile phase consisted of acetonitrile:0.05 M KH(2)PO(4):triethylamine (22:100:0.15) adjusted to pH 4.8. The column was maintained at 25 degrees C and 20 microL of solutions was injected. Photodiode array detector was used to test the peak purity and the chromatograms were extracted at 210 nm. Naphazoline hydrochloride was used as internal standard. The method was validated with respect to specificity, linearity, accuracy, precision, limit of quantitation and limit of detection. The validation acceptance criteria were met in all cases. Identification of the pure peaks was carried out using library match programmer and wavelengths of derivative optima of the spectrograms of the peaks. The method was successfully applied to the determination of the investigated drugs and their degradation products in different batches of granisetron injections. The method was proved to be sensitive for the determination down to 0.03 and 0.01% of granisetron degradation product and benzaldehyde, respectively, which are far below the compendia limits for testing these degradation products in their corresponding intact drugs. Copyright 2010 Elsevier B.V. All rights reserved.

Evaluation of Seasonal Changes in Fitness, Anthropometrics, and Body Composition in Collegiate Division Ii Female Soccer Players.

PubMed

Peart, Ashley N; Nicks, Clayton R; Mangum, Michael; Tyo, Brian M

2018-03-22

The purpose of this study was to investigate anthropometrics, body composition, aerobic and anaerobic fitness of collegiate Division II female soccer players throughout a calendar year. Eighteen (20 ± 0.9y) NCAA division II female soccer players from the same team participated in the study. Anthropometrics and body composition variables were assessed in addition to the Counter Movement Jump (CMJ), Wingate Anaerobic Test (WAT), and peak oxygen uptake (VO2peak). Data were collected over five time points: end of competitive seasons (ECS1 and ECS2), beginning of off-season (BOS), end of off-season (EOS), and pre-season (PS). Repeated-measures analysis of variance (ANOVA) were conducted to compare test scores among all five data collection points. Where appropriate, Bonferroni post-hoc tests were used to determine which points were significantly different. Hip circumference (HC) decreased significantly (p < 0.001) from EOS (98.47 ± 6.5 cm) to PS (94.46 ± 6.8 cm). Fat mass (FM) (12.73 ± 5.4 kg) was significantly different in ECS2 compared to BOS and EOS means (p ≤ 0.05) and percentage of body fat (%BF) (20.08 ± 5.44) significantly different in ECS2 compared to ECS1, BOS, and EOS means (p ≤ 0.05), while fat-free mass (FFM) was maintained from ECS1 to ECS2. CMJ, WAT, and VO2peak performance did not significantly change from ECS1 to ECS2. Anthropometrics and body composition results are similar to previous studies measuring Division II to professional female soccer players. CMJ results remained consistent and are comparable to results on Division I female soccer players. Coaches and researchers can use these data to help design and evaluate training programs throughout a calendar year.

Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles.

PubMed

Zhao, Wei; Ji, Songbai

2017-04-01

Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29-17.89 % in the whole brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9 %) but not pattern (correlation coefficient of 0.94-0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91 % on average, with a typical range of 0-6 %). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future.

Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles

PubMed Central

Zhao, Wei; Ji, Songbai

2016-01-01

Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles, and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction, and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29–17.89% in the whole-brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9%) but not pattern (correlation coefficient of 0.94–0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91% on average, with a typical range of 0–6%). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future. PMID:27644441

VARIABILITY OF PEAK SHOULDER FORCE DURING WHEELCHAIR PROPULSION IN MANUAL WHEELCHAIR USERS WITH AND WITHOUT SHOULDER PAIN

PubMed Central

Moon, Y.; Chandrasekaran, J.; Hsu, I.M.K.; Rice, I.M.; Hsiao-Wecksler, E.T.; Sosnoff, J.J.

2013-01-01

Background Manual wheelchair users report a high prevalence of shoulder pain. Growing evidence shows that variability in forces applied to biological tissue is related to musculoskeletal pain. The purpose of this study was to examine the variability of forces acting on the shoulder during wheelchair propulsion as a function of shoulder pain. Methods Twenty-four manual wheelchair users (13 with pain, 11 without pain) participated in the investigation. Kinetic and kinematic data of wheelchair propulsion were recorded for three minutes maintaining a constant speed at three distinct propulsion speeds (fast speed of 1.1 m/s, a self-selected speed, and a slow speed of 0.7 m/s). Peak resultant shoulder forces in the push phase were calculated using inverse dynamics. Within individual variability was quantified as the coefficient of variation of cycle to cycle peak resultant forces. Findings There was no difference in mean peak shoulder resultant force between groups. The pain group had significantly smaller variability of peak resultant force than the no pain group (p < 0.01, η2 = 0.18). Interpretation The observations raise the possibility that propulsion variability could be a novel marker of upper limb pain in manual wheelchair users. PMID:24210512

Cardiorespiratory responses to Yo-yo Intermittent Endurance Test in nonelite youth soccer players.

PubMed

Castagna, Carlo; Impellizzeri, Franco M; Belardinelli, Romualdo; Abt, Grant; Coutts, Aaron; Chamari, Karim; D'Ottavio, Stefano

2006-05-01

This study examined the validity of the Yo-yo Intermittent Endurance Test (Level 1; YYIET) as indicator of aerobic power in youth soccer players. Cardiorespiratory responses were determined in 18 moderately trained nonelite youth soccer players (age, 16.6 +/- 0.8 years; height, 178.7 +/- 6.2 cm; body mass, 69.8 +/- 6.0 kg; VO2peak, 52.8 +/- 7.4 ml x kg(-1) x min(-1)) while performing the YYIET and an incremental treadmill test. Maximal heart rate (HRmax), respiratory exchange ratio (RER), O2 pulse, VO2peak, and maximal ventilation (VEmax) were measured. Group YYIET VO2peak, HRmax, RER, and O2 pulse were not significantly different from treadmill responses (p > 0.05). VEmax was significantly lower (p < 0.05) during the YYIET compared to the treadmill condition. No significant correlation was found between treadmill VO2peak and YYIET performance (p > 0.05). This study showed that the YYIET elicits peak VO2 and HR responses. However, YYIET performance results were not related to VO2peak measured in laboratory. Furthermore, the individual VO2peak reached during the TM did not reflect the VO2peak obtained during the YYIET, as shown by the large limits of agreement. As a consequence, compared to other shuttle run field tests, YYIET seems to be a weak indicator of aerobic power in youth moderately trained youth soccer player.

Six-minute walking test in children with ESRD: discrimination validity and construct validity.

PubMed

Takken, Tim; Engelbert, Raoul; van Bergen, Monique; Groothoff, Jaap; Nauta, Jeroen; van Hoeck, Koen; Lilien, Marc; Helders, Paul

2009-11-01

The six-minute walking test (6MWT) may be a practical test for the evaluation functional exercise capacity in children with end-stage renal disease (ESRD). The aim of this study was to investigate the 6MWT performance in children with ESRD compared to reference values obtained in healthy children and, secondly, to study the relationship between 6MWT performance with anthropometric variables, clinical parameters, aerobic capacity and muscle strength. Twenty patients (13 boys and seven girls; mean age 14.1 +/- 3.4 years) on dialysis participated in this study. Anthropometrics were taken in a standardized manner. The 6MWT was performed in a 20-m-long track in a straight hallway. Aerobic fitness was measured using a cycle ergometer test to determine peak oxygen uptake (V O(2peak)), peak rate (W(peak)) and ventilatory threshold (VT). Muscle strength was measured using hand-held myometry. Children with ESRD showed a reduced 6MWT performance (83% of predicted, p < 0.0001), irrespective of the reference values used. The strongest predictors of 6MWT performance were haematocrit and height. Regression models explained 59% (haematocrit and height) to 60% (haematocrit) of the variance in 6MWT performance. 6MWT performance was not associated with V O(2peak), strength, or other anthropometric variables, but it was significantly associated with haematocrit and height. Children with ESRD scored lower on the 6MWT than healthy children. Based on these results, the 6MWT may be a useful instrument for monitoring clinical status in children with ESRD, however it cannot substitute for other fitness tests, such as a progressive exercise test to measure V O(2peak) or muscle strength tests.

Smith machine counterbalance system affects measures of maximal bench press throw performance.

PubMed

Vingren, Jakob L; Buddhadev, Harsh H; Hill, David W

2011-07-01

Equipment with counterbalance weight systems is commonly used for the assessment of performance in explosive resistance exercise movements, but it is not known if such systems affect performance measures. The purpose of this study was to determine the effect of using a counterbalance weight system on measures of smith machine bench press throw performance. Ten men and 14 women (mean ± SD: age, 25 ± 4 years; height, 173 ± 10 cm; weight, 77.7 ± 18.3 kg) completed maximal smith machine bench press throws under 4 different conditions (2 × 2; counterbalance × load): with or without a counterbalance weight system and using 'light' or 'moderate' net barbell loads. Performance variables (peak force, peak velocity, and peak power) were measured using a linear accelerometer attached to the barbell. The counterbalance weight system resulted in significant (p < 0.001) reductions in measures of peak force (mean difference ± standard error: light: -112 ± 20 N; moderate: -140 ± 23 N), peak velocity (light: -0.49 ± 0.10 m·s; moderate: -0.33 ± 0.07 m·s), and peak power (light: -220 ± 43 W; moderate: -143 ± 28 W) compared with no counterbalance system for both load conditions. Load condition did not affect absolute or percentage reductions from the counterbalance weight system for any variable. In conclusion, the use of a counterbalance weight system reduces accelerometer-based performance measures for the bench press throw exercise at light and moderate loads. This reduction in measures is likely because of an increase in the external resistance during the movement, which results in a discrepancy between the manually input and the actual value for external load. A counterbalance weight system should not be used when measuring performance in explosive resistance exercises with an accelerometer.

Mechanisms of Microwave Induced Damage in Biologic Materials

DTIC Science & Technology

1991-01-01

W. D. Winters and I. L. Cameron (1990) Influence of 60-Hz magnetic fields on sea urchin development. Bioelectromagnetics, 11:37-46. II I I I I I I I...t SEM ) that of control values, and by 8-hour peaked at 1.92 (± 0.07) times control values. Continued exposure did not i maintain ODC activity at an

Aspen fencing in northern Arizona: A 15-year perspective

Treesearch

James M. Rolf

2001-01-01

Aspen clearcuts in the 1960s and 1970s on the Peaks Ranger District of the Coconino National Forest in northern Arizona failed to regenerate successfully because of browsing primarily by elk. Since 1985, over 400 acres have been successfully regenerated using fencing of various designs to exclude elk. The expense and visual impact of establishing and maintaining over...

First parity evaluation of peak milk yield for range cows developed in the same ecophysiological system but receiving different concentrations of harvested feed inputs

USDA-ARS?s Scientific Manuscript database

Can range livestock producers reduce harvested feed inputs, during heifer development, and maintain production goals? To address this, we conducted a two year study measuring milk production (kg/d) and milk constituent concentrations (g/d) for 16 primiparous beef cows each year that were born from d...

Creating a Responsive Website: PPLD Friends--A Case Study

ERIC Educational Resources Information Center

Franklyn, Virginia

2013-01-01

The Friends of the Pikes Peak Library District (PPLD) had a legacy website that was remotely hosted and maintained by a volunteer. They wanted a more significant presence on PPLD.org and an easier interface with which to update information. The developers decided to create a new Friends site in Drupal, using RWD, CSS3, and HTML5. The plan was to…

Characterization of peak capacity of microbore liquid chromatography columns using gradient kinetic plots.

PubMed

Hetzel, Terence; Blaesing, Christina; Jaeger, Martin; Teutenberg, Thorsten; Schmidt, Torsten C

2017-02-17

The performance of micro-liquid chromatography columns with an inner diameter of 0.3mm was investigated on a dedicated micro-LC system for gradient elution. Core-shell as well as fully porous particle packed columns were compared on the basis of peak capacity and gradient kinetic plot limits. The results for peak capacity showed the superior performance of columns packed with sub-2μm fully porous particles compared to 3.0μm fully porous and 2.7μm core-shell particles within a range of different gradient time to column void time ratios. For ultra-fast chromatography a maximum peak capacity of 16 can be obtained using a 30s gradient for the sub-2μm fully porous particle packed column. A maximum peak capacity of 121 can be achieved using a 5min gradient. In addition, the influence of an alternative detector cell on the basis of optical waveguide technology and contributing less to system variance was investigated showing an increased peak capacity for all applied gradient time/column void time ratios. Finally, the influence of pressure was evaluated indicating increased peak capacity for maximum performance whereas a limited benefit for ultra-fast chromatography with gradient times below 30s was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative Analysis of Mass Spectral Similarity Measures on Peak Alignment for Comprehensive Two-Dimensional Gas Chromatography Mass Spectrometry

PubMed Central

2013-01-01

Peak alignment is a critical procedure in mass spectrometry-based biomarker discovery in metabolomics. One of peak alignment approaches to comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS) data is peak matching-based alignment. A key to the peak matching-based alignment is the calculation of mass spectral similarity scores. Various mass spectral similarity measures have been developed mainly for compound identification, but the effect of these spectral similarity measures on the performance of peak matching-based alignment still remains unknown. Therefore, we selected five mass spectral similarity measures, cosine correlation, Pearson's correlation, Spearman's correlation, partial correlation, and part correlation, and examined their effects on peak alignment using two sets of experimental GC×GC-MS data. The results show that the spectral similarity measure does not affect the alignment accuracy significantly in analysis of data from less complex samples, while the partial correlation performs much better than other spectral similarity measures when analyzing experimental data acquired from complex biological samples. PMID:24151524

Average current is better than peak current as therapeutic dosage for biphasic waveforms in a ventricular fibrillation pig model of cardiac arrest.

PubMed

Chen, Bihua; Yu, Tao; Ristagno, Giuseppe; Quan, Weilun; Li, Yongqin

2014-10-01

Defibrillation current has been shown to be a clinically more relevant dosing unit than energy. However, the effects of average and peak current in determining shock outcome are still undetermined. The aim of this study was to investigate the relationship between average current, peak current and defibrillation success when different biphasic waveforms were employed. Ventricular fibrillation (VF) was electrically induced in 22 domestic male pigs. Animals were then randomized to receive defibrillation using one of two different biphasic waveforms. A grouped up-and-down defibrillation threshold-testing protocol was used to maintain the average success rate of 50% in the neighborhood. In 14 animals (Study A), defibrillations were accomplished with either biphasic truncated exponential (BTE) or rectilinear biphasic waveforms. In eight animals (Study B), shocks were delivered using two BTE waveforms that had identical peak current but different waveform durations. Both average and peak currents were associated with defibrillation success when BTE and rectilinear waveforms were investigated. However, when pathway impedance was less than 90Ω for the BTE waveform, bivariate correlation coefficient was 0.36 (p=0.001) for the average current, but only 0.21 (p=0.06) for the peak current in Study A. In Study B, a high defibrillation success (67.9% vs. 38.8%, p<0.001) was observed when the waveform delivered more average current (14.9±2.1A vs. 13.5±1.7A, p<0.001) while keeping the peak current unchanged. In this porcine model of VF, average current was better than peak current to be an adequate parameter to describe the therapeutic dosage when biphasic defibrillation waveforms were used. The institutional protocol number: P0805. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

REMOVING COOL CORES AND CENTRAL METALLICITY PEAKS IN GALAXY CLUSTERS WITH POWERFUL ACTIVE GALACTIC NUCLEUS OUTBURSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo Fulai; Mathews, William G., E-mail: fulai@ucolick.or

2010-07-10

Recent X-ray observations of galaxy clusters suggest that cluster populations are bimodally distributed according to central gas entropy and are separated into two distinct classes: cool core (CC) and non-cool core (NCC) clusters. While it is widely accepted that active galactic nucleus (AGN) feedback plays a key role in offsetting radiative losses and maintaining many clusters in the CC state, the origin of NCC clusters is much less clear. At the same time, a handful of extremely powerful AGN outbursts have recently been detected in clusters, with a total energy {approx}10{sup 61}-10{sup 62} erg. Using two-dimensional hydrodynamic simulations, we showmore » that if a large fraction of this energy is deposited near the centers of CC clusters, which is likely common due to dense cores, these AGN outbursts can completely remove CCs, transforming them to NCC clusters. Our model also has interesting implications for cluster abundance profiles, which usually show a central peak in CC systems. Our calculations indicate that during the CC to NCC transformation, AGN outbursts efficiently mix metals in cluster central regions and may even remove central abundance peaks if they are not broad enough. For CC clusters with broad central abundance peaks, AGN outbursts decrease peak abundances, but cannot effectively destroy the peaks. Our model may simultaneously explain the contradictory (possibly bimodal) results of abundance profiles in NCC clusters, some of which are nearly flat, while others have strong central peaks similar to those in CC clusters. A statistical analysis of the sizes of central abundance peaks and their redshift evolution may shed interesting insights on the origin of both types of NCC clusters and the evolution history of thermodynamics and AGN activity in clusters.« less

Comparative analysis of peak-detection techniques for comprehensive two-dimensional chromatography.

PubMed

Latha, Indu; Reichenbach, Stephen E; Tao, Qingping

2011-09-23

Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful technology for separating complex samples. The typical goal of GC×GC peak detection is to aggregate data points of analyte peaks based on their retention times and intensities. Two techniques commonly used for two-dimensional peak detection are the two-step algorithm and the watershed algorithm. A recent study [4] compared the performance of the two-step and watershed algorithms for GC×GC data with retention-time shifts in the second-column separations. In that analysis, the peak retention-time shifts were corrected while applying the two-step algorithm but the watershed algorithm was applied without shift correction. The results indicated that the watershed algorithm has a higher probability of erroneously splitting a single two-dimensional peak than the two-step approach. This paper reconsiders the analysis by comparing peak-detection performance for resolved peaks after correcting retention-time shifts for both the two-step and watershed algorithms. Simulations with wide-ranging conditions indicate that when shift correction is employed with both algorithms, the watershed algorithm detects resolved peaks with greater accuracy than the two-step method. Copyright © 2011 Elsevier B.V. All rights reserved.

Complete inhibition of creatine kinase in isolated perfused rat hearts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fossel, E.T.; Hoefeler, H.

1987-01-01

Transient exposure of an isolated isovolumic perfused rat heart to low concentrations (0.5 mM) of perfusate-born iodoacetamide resulted in complete inhibition of creatine kinase and partial inhibition of glyceraldehyde-3-phosphate dehydrogenase in the heart. At low levels of developed pressure, hearts maintained mechanical function, ATP, and creatine phosphate levels at control values. However, iodoacetamide-inhibited hearts were unable to maintain control values of end diastolic pressure or peak systolic pressure as work load increased. Global ischemia resulted in loss of all ATP without loss of creatine phosphate, indicating lack of active creatine kinase. These results indicate that isovolumic perfused rat hearts aremore » able to maintain normal function and normal levels of high-energy phosphates without active creatine kinase at low levels of developed pressure. /sup 31/P-NMR of the heart was carried out.« less

Extension of supercontinuum spectrum, generated in polarization-maintaining photonic crystal fiber, using chirped femtosecond pulses

NASA Astrophysics Data System (ADS)

Vengelis, Julius; Jarutis, Vygandas; Sirutkaitis, Valdas

2018-01-01

We present results of experimental and numerical investigation of supercontinuum (SC) generation in polarization-maintaining photonic crystal fiber (PCF) using chirped femtosecond pulses. The initial unchirped pump pulse source was a mode-locked Yb:KGW laser generating 52-nJ energy, 110-fs duration pulses at 1030 nm with a 76-MHz repetition rate. The nonlinear medium was a 32-cm-long polarization-maintaining PCF manufactured by NKT Photonics A/S. We demonstrated the influence of pump pulse chirp on spectral characteristics of a SC. We showed that by chirping pump pulses positively or negatively one can obtain a broader SC spectrum than in the case of unchirped pump pulses at the same peak power. Moreover, the extension can be controlled by changing the amount of pump pulse chirp. Numerical simulation results also indicated that pump pulse chirp yields an extension of SC spectrum.

Integrated polarizers based on tapered highly birefringent photonic crystal fibers.

PubMed

Romagnoli, Priscila; Biazoli, Claudecir R; Franco, Marcos A R; Cordeiro, Cristiano M B; de Matos, Christiano J S

2014-07-28

This paper proposes and demonstrates the creation of sections with a high polarization dependent loss (PDL) in a commercial highly birefringent (polarization maintaining) photonic crystal fiber (PCF), via tapering with pressure applied to the holes. The tapers had a 1-cm-long uniform section with a 66% scale reduction, in which the original microstructure aspect ratio was kept by the pressure application. The resulting waveguides show polarizing action across the entire tested wavelength range, 1510-1600 nm, with a peak PDL of 35.3 dB/cm (c.f. ~1 dB/cm for a typical commercial polarizing fiber). The resulting structure, as well as its production, is extremely simple, and enable a small section with a high PDL to be obtained in a polarization maintaining PCF, meaning that the polarization axes in the polarizing and polarization maintaining sections are automatically aligned.

Buoyancy-assisted mixed convective flow over backward-facing step in a vertical duct using nanofluids

NASA Astrophysics Data System (ADS)

Mohammed, H. A.; Al-aswadi, A. A.; Yusoff, M. Z.; Saidur, R.

2012-03-01

Laminar mixed convective buoyancy assisting flow through a two-dimensional vertical duct with a backward-facing step using nanofluids as a medium is numerically simulated using finite volume technique. Different types of nanoparticles such as Au, Ag, Al2O3, Cu, CuO, diamond, SiO2 and TiO2 with 5 % volume fraction are used. The wall downstream of the step was maintained at a uniform wall temperature, while the straight wall that forms the other side of the duct was maintained at constant temperature equivalent to the inlet fluid temperature. The walls upstream of the step and the backward-facing step were considered as adiabatic surfaces. The duct has a step height of 4.9 mm and an expansion ratio of 1.942, while the total length in the downstream of the step is 0.5 m. The downstream wall was fixed at uniform wall temperature 0 ≤ Δ T≤ 30 °C, which was higher than the inlet flow temperature. The Reynolds number in the range of 75 ≤ Re ≤ 225 was considered. It is found that a recirculation region was developed straight behind the backward-facing step which appeared between the edge of the step and few millimeters before the corner which connect the step and the downstream wall. In the few millimeters gap between the recirculation region and the downstream wall, a U-turn flow was developed opposite to the recirculation flow which mixed with the unrecirculated flow and traveled along the channel. Two maximum and one minimum peaks in Nusselt number were developed along the heated downstream wall. It is inferred that Au nanofluid has the highest maximum peaks while diamond nanofluid has the highest minimum peak. Nanofluids with a higher Prandtl number have a higher peak of Nusselt numbers after the separation and the recirculation flow disappeared.

Peak oxygen consumption measured during the stair-climbing test in lung resection candidates.

PubMed

Brunelli, Alessandro; Xiumé, Francesco; Refai, Majed; Salati, Michele; Di Nunzio, Luca; Pompili, Cecilia; Sabbatini, Armando

2010-01-01

The stair-climbing test is commonly used in the preoperative evaluation of lung resection candidates, but it is difficult to standardize and provides little physiologic information on the performance. To verify the association between the altitude and the V(O2peak) measured during the stair-climbing test. 109 consecutive candidates for lung resection performed a symptom-limited stair-climbing test with direct breath-by-breath measurement of V(O2peak) by a portable gas analyzer. Stepwise logistic regression and bootstrap analyses were used to verify the association of several perioperative variables with a V(O2peak) <15 ml/kg/min. Subsequently, multiple regression analysis was also performed to develop an equation to estimate V(O2peak) from stair-climbing parameters and other patient-related variables. 56% of patients climbing <14 m had a V(O2peak) <15 ml/kg/min, whereas 98% of those climbing >22 m had a V(O2peak) >15 ml/kg/min. The altitude reached at stair-climbing test resulted in the only significant predictor of a V(O2peak) <15 ml/kg/min after logistic regression analysis. Multiple regression analysis yielded an equation to estimate V(O2peak) factoring altitude (p < 0.0001), speed of ascent (p = 0.005) and body mass index (p = 0.0008). There was an association between altitude and V(O2peak) measured during the stair-climbing test. Most of the patients climbing more than 22 m are able to generate high values of V(O2peak) and can proceed to surgery without any additional tests. All others need to be referred for a formal cardiopulmonary exercise test. In addition, we were able to generate an equation to estimate V(O2peak), which could assist in streamlining the preoperative workup and could be used across different settings to standardize this test. Copyright (c) 2010 S. Karger AG, Basel.

Six Ways To Foster Peak Performance.

ERIC Educational Resources Information Center

Sevilla, Christine; Wells, Timothy D.

1999-01-01

Discusses six initiatives that organizations can support to ensure peak performance: individual knowledge portfolios; mentoring and apprenticeship relationships; electronic conferencing systems; organizational knowledge repository; community of practice; reward and recognition. Defines each initiative and describes how to make each one work in an…

Gait biomechanics of skipping are substantially different than those of running.

PubMed

McDonnell, Jessica; Willson, John D; Zwetsloot, Kevin A; Houmard, Joseph; DeVita, Paul

2017-11-07

The inherit injury risk associated with high-impact exercises calls for alternative ways to achieve the benefits of aerobic exercise while minimizing excessive stresses to body tissues. Skipping presents such an alternative, incorporating double support, flight, and single support phases. We used ground reaction forces (GRFs), lower extremity joint torques and powers to compare skipping and running in 20 healthy adults. The two consecutive skipping steps on each limb differed significantly from each other, and from running. Running had the longest step length, the highest peak vertical GRF, peak knee extensor torque, and peak knee negative and positive power and negative and positive work. Skipping had the greater cadence, peak horizontal GRF, peak hip and ankle extensor torques, peak ankle negative power and work, and peak ankle positive power. The second vs first skipping step had the shorter step length, higher cadence, peak horizontal GRF, peak ankle extensor torque, and peak ankle negative power, negative work, and positive power and positive work. The first skipping step utilized predominately net negative joint work (eccentric muscle action) while the second utilized predominately net positive joint work (concentric muscle action). The skipping data further highlight the persistence of net negative work performed at the knee and net positive work performed at the ankle across locomotion gaits. Evidence of step segregation was seen in distribution of the braking and propelling impulses and net work produced across the hip, knee, and ankle joints. Skipping was substantially different than running and was temporally and spatially asymmetrical with successive foot falls partitioned into a dominant function, either braking or propelling whereas running had a single, repeated step in which both braking and propelling actions were performed equally. Copyright © 2017 Elsevier Ltd. All rights reserved.

Relative changes with contraction in the central excitability state of the tibialis anterior and calf muscles.

PubMed Central

Fisher, M A

1980-01-01

F responses were recorded from the surface of the tibialis muscle and medial aspect of the soleus muscle in 14 normal subjects. The persistence (that is the fraction of measurable F responses found with a series of supramaximal stimuli) and average F amplitudes (measured peak-to-peak and based on at least five F responses) were determined both at rest and with isometric contraction with the ankle maintained at 90 degrees. Although the persistence at rest was significantly less in the tibialis anterior soleus than the (p less than 0.001), no significant difference was found with the muscles contracted. This was associated with a significant increase in both average F amplitudes and average F amplitude/direct motor response ratios in the tibialis anterior in comparison to the soleus. In four of the subjects, studies were also performed when the H reflex in the soleus muscle was eliminated by thigh compression. Comparable changes in both F response persistence and average F amplitude were found with and without an H reflex. These data indicate that, in contrast to the situation at rest, with isometric contraction the "central excitatory state" of the tibialis anterior is at least as great as in its antagonist antigravity muscles and that this is not due simply to increased large fiber reflex input associated with agonist contraction. PMID:7373321

Improving the Q:H strength ratio in women using plyometric exercises.

PubMed

Tsang, Kavin K W; DiPasquale, Angela A

2011-10-01

Plyometric training programs have been implemented in anterior cruciate ligament injury prevention programs. Plyometric exercises are designed to aid in the improvement of muscle strength and neuromuscular control. Our purpose was to examine the effects of plyometric training on lower leg strength in women. Thirty (age = 20.3 ± 1.9 years) recreationally active women were divided into control and experimental groups. The experimental group performed a plyometric training program for 6 weeks, 3 d·wk(-1). All subjects attended 4 testing sessions: before the start of the training program and after weeks 2, 4, and 6. Concentric quadriceps and hamstring strength (dominant leg) was assessed using an isokinetic dynamometer at speeds of 60 and 120°·s(-1). Peak torque, average peak torque, and average power (AvgPower) were measured. The results revealed a significant (p < 0.05) interaction between time and group for flexion PkTq and AvgPower at 120°·s(-1). Post hoc analysis further revealed that PkTq at 120°·s(-1) was greater in the plyometric group than in the control group at testing session 4 and that AvgPower was greater in the plyometric group than in the control group in testing sessions 2-4. Our results indicate that the plyometric training program increased hamstring strength while maintaining quadriceps strength, thereby improving the Q:H strength ratio.

Response of end tidal CO2 pressure to impulse exercise.

PubMed

Yano, T; Afroundeh, R; Yamanak, R; Arimitsu, T; Lian, C-S; Shirkawa, K; Yunoki, T

2014-03-01

The purpose of the present study was to examine how end tidal CO(2) pressure (PETCO(2)) is controlled in impulse exercise. After pre-exercise at 25 watts for 5 min, impulse exercise for 10 sec with 200 watts followed by post exercise at 25 watts was performed. Ventilation (VE) significantly increased until the end of impulse exercise and significantly re-increased after a sudden decrease. Heart rate (HR) significantly increased until the end of impulse exercise and then decreased to the pre-exercise level. PETCO(2) remained constant during impulse exercise. PETCO(2) significantly increased momentarily after impulse exercise and then significantly decreased to the pre-exercise level. PETCO(2) showed oscillation. The average peak frequency of power spectral density in PETCO(2) appeared at 0.0078 Hz. Cross correlations were obtained after impulse exercise. The peak cross correlations between VE and PETCO(2), HR and PETCO(2), and VE and HR were 0.834 with a time delay of -7 sec, 0.813 with a time delay of 7 sec and 0.701 with a time delay of -15 sec, respectively. We demonstrated that PETCO(2) homeodynamics was interactively maintained by PETCO(2) itself, CO(2) transportation (product of cardiac output and mixed venous CO(2) content) into the lungs by heart pumping and CO(2) elimination by ventilation, and it oscillates as a result of their interactions.

Functional overreaching: the key to peak performance during the taper?

PubMed

Aubry, Anaël; Hausswirth, Christophe; Louis, Julien; Coutts, Aaron J; LE Meur, Yann

2014-09-01

The purpose of this study is to examine whether performance supercompensation during taper is maximized in endurance athletes after experiencing overreaching during an overload training (OT) period. Thirty-three trained male triathletes were assigned to either OT (n = 23) or normal training groups (n = 10, CTL) during 8 wk. Cycling performance and maximal oxygen uptake (V˙O2max) were measured after 1 wk of moderate training, a 3-wk period of OT, and then each week during 4-wk taper. Eleven of the 23 subjects from the OT group were diagnosed as functionally overreached (F-OR) after the overload period (decreased performance with concomitant high perceived fatigue), whereas the 12 other subjects were only acutely fatigued (AF) (no decrease in performance). According to qualitative statistical analysis, the AF group demonstrated a small to large greater peak performance supercompensation than the F-OR group (2.6% ± 1.1%) and the CTL group (2.6% ± 1.6%). V˙O2max increased significantly from baseline at peak performance only in the CTL and AF groups. Of the peak performances, 60%, 83%, and 73% occurred within the two first weeks of taper in CTL, AF, and OR, respectively. Ten cases of infection were reported during the study with higher prevalence in F-OR (70%) than that in AF (20%) and CTL (10%). This study showed that 1) greater gains in performance and V˙O2max can be achieved when higher training load is prescribed before the taper but not in the presence of F-OR; 2) peak performance is not delayed during taper when heavy training loads are completed immediately prior; and 3) F-OR provides higher risk for training maladaptation, including increased infection risks.

Climate-related variation in plant peak biomass and growth phenology across Pacific Northwest tidal marshes

USGS Publications Warehouse

Buffington, Kevin J.; Dugger, Bruce D.; Thorne, Karen M.

2018-01-01

The interannual variability of tidal marsh plant phenology is largely unknown and may have important ecological consequences. Marsh plants are critical to the biogeomorphic feedback processes that build estuarine soils, maintain marsh elevation relative to sea level, and sequester carbon. We calculated Tasseled Cap Greenness, a metric of plant biomass, using remotely sensed data available in the Landsat archive to assess how recent climate variation has affected biomass production and plant phenology across three maritime tidal marshes in the Pacific Northwest of the United States. First, we used clipped vegetation plots at one of our sites to confirm that tasseled cap greenness provided a useful measure of aboveground biomass (r2 = 0.72). We then used multiple measures of biomass each growing season over 20–25 years per study site and developed models to test how peak biomass and the date of peak biomass varied with 94 climate and sea-level metrics using generalized linear models and Akaike Information Criterion (AIC) model selection. Peak biomass was positively related to total annual precipitation, while the best predictor for date of peak biomass was average growing season temperature, with the peak 7.2 days earlier per degree C. Our study provides insight into how plants in maritime tidal marshes respond to interannual climate variation and demonstrates the utility of time-series remote sensing data to assess ecological responses to climate stressors.

Performance evaluation of GIM-TEC assimilation of the IRI-Plas model at two equatorial stations in the American sector

NASA Astrophysics Data System (ADS)

Adebiyi, S. J.; Adebesin, B. O.; Ikubanni, S. O.; Joshua, B. W.

2017-05-01

Empirical models of the ionosphere, such as the International Reference Ionosphere (IRI) model, play a vital role in evaluating the environmental effect on the operation of space-based communication and navigation technologies. The IRI extended to Plasmasphere (IRI-Plas) model can be adjusted with external data to update its electron density profile while still maintaining the overall integrity of the model representations. In this paper, the performance of the total electron content (TEC) assimilation option of the IRI-Plas at two equatorial stations, Jicamarca, Peru (geographic: 12°S, 77°W, dip angle 0.8°) and Cachoeira Paulista, Brazil (Geographic: 22.7°S, 45°W, dip angle -26°), is examined during quiet and disturbed conditions. TEC, F2 layer critical frequency (foF2), and peak height (hmF2) predicted when the model is operated without external input were used as a baseline in our model evaluation. Results indicate that TEC predicted by the assimilation option generally produced smaller estimation errors compared to the "no extra input" option during quiet and disturbed conditions. Generally, the error is smaller at the equatorial trough than near the crest for both quiet and disturbed days. With assimilation option, there is a substantial improvement of storm time estimations when compared with quiet time predictions. The improvement is, however, independent on storm's severity. Furthermore, the modeled foF2 and hmF2 are generally poor with TEC assimilation, particularly the hmF2 prediction, at the two locations during both quiet and disturbed conditions. Consequently, IRI-Plas model assimilated with TEC value only may not be sufficient where more realistic instantaneous values of peak parameters are required.

Using Low Levels of Stochastic Vestibular Stimulation to Improve Balance Function

PubMed Central

Goel, Rahul; Kofman, Igor; Jeevarajan, Jerome; De Dios, Yiri; Cohen, Helen S.; Bloomberg, Jacob J.; Mulavara, Ajitkumar P.

2015-01-01

Low-level stochastic vestibular stimulation (SVS) has been associated with improved postural responses in the medio-lateral (ML) direction, but its effect in improving balance function in both the ML and anterior-posterior (AP) directions has not been studied. In this series of studies, the efficacy of applying low amplitude SVS in 0–30 Hz range between the mastoids in the ML direction on improving cross-planar balance function was investigated. Forty-five (45) subjects stood on a compliant surface with their eyes closed and were instructed to maintain a stable upright stance. Measures of stability of the head, trunk, and whole body were quantified in ML, AP and combined APML directions. Results show that binaural bipolar SVS given in the ML direction significantly improved balance performance with the peak of optimal stimulus amplitude predominantly in the range of 100–500 μA for all the three directions, exhibiting stochastic resonance (SR) phenomenon. Objective perceptual and body motion thresholds as estimates of internal noise while subjects sat on a chair with their eyes closed and were given 1 Hz bipolar binaural sinusoidal electrical stimuli were also measured. In general, there was no significant difference between estimates of perceptual and body motion thresholds. The average optimal SVS amplitude that improved balance performance (peak SVS amplitude normalized to perceptual threshold) was estimated to be 46% in ML, 53% in AP, and 50% in APML directions. A miniature patch-type SVS device may be useful to improve balance function in people with disabilities due to aging, Parkinson’s disease or in astronauts returning from long-duration space flight. PMID:26295807

A systems-based investigation into vitamin D and skeletal muscle repair, regeneration, and hypertrophy.

PubMed

Owens, Daniel J; Sharples, Adam P; Polydorou, Ioanna; Alwan, Nura; Donovan, Timothy; Tang, Jonathan; Fraser, William D; Cooper, Robert G; Morton, James P; Stewart, Claire; Close, Graeme L

2015-12-15

Skeletal muscle is a direct target for vitamin D. Observational studies suggest that low 25[OH]D correlates with functional recovery of skeletal muscle following eccentric contractions in humans and crush injury in rats. However, a definitive association is yet to be established. To address this gap in knowledge in relation to damage repair, a randomised, placebo-controlled trial was performed in 20 males with insufficient concentrations of serum 25(OH)D (45 ± 25 nmol/l). Prior to and following 6 wk of supplemental vitamin D3 (4,000 IU/day) or placebo (50 mg of cellulose), participants performed 20 × 10 damaging eccentric contractions of the knee extensors, with peak torque measured over the following 7 days of recovery. Parallel experimentation using isolated human skeletal muscle-derived myoblast cells from biopsies of 14 males with low serum 25(OH)D (37 ± 11 nmol/l) were subjected to mechanical wound injury, which enabled corresponding in vitro studies of muscle repair, regeneration, and hypertrophy in the presence and absence of 10 or 100 nmol 1α,25(OH)2D3. Supplemental vitamin D3 increased serum 25(OH)D and improved recovery of peak torque at 48 h and 7 days postexercise. In vitro, 10 nmol 1α,25(OH)2D3 improved muscle cell migration dynamics and resulted in improved myotube fusion/differentiation at the biochemical, morphological, and molecular level together with increased myotube hypertrophy at 7 and 10 days postdamage. Together, these preliminary data are the first to characterize a role for vitamin D in human skeletal muscle regeneration and suggest that maintaining serum 25(OH)D may be beneficial for enhancing reparative processes and potentially for facilitating subsequent hypertrophy. Copyright © 2015 the American Physiological Society.

Development of the Pushered Single Shell Experimental Platform on NIF

NASA Astrophysics Data System (ADS)

Salmonson, Jay; Dewald, Eduard; Graziani, Frank; MacLaren, Stephan; Pino, Jesse; Ralph, Joseph; Sacks, Ryan; Smalyuk, Vladimir; Tipton, Robert

2017-10-01

The goal of the Pushered Single Shell (PSS) experimental campaign is to study mix of partially ionized ablator material into the hotspot. To do this we use a uniformly Si doped plastic capsule, the inner few microns of which can be doped with a few percent Ge. To diagnose mix, we use separated reactants; deuterating the inner Ge-doped layer, CD/Ge, while putting Tritium into the Hydrogen capsule fill gas. Mix is then inferred by measuring the neutron yields from DD, DT, and TT reactions. In order to accentuate the cooling of the hot-spot due to Bremsstrahlung radiation when Ge is present, we required high hot-spot ion temperatures: 3 keV. This, in turn, requires a fast, symmetric implosion. Using the Two-Shock campaign as a starting point, we increased the capsule radius by 25% to 844 μm and the peak laser power by over 10% to 475 TW. We also used a low, 0.3 mg/cc, He fill in the hohlraum to maintain control over implosion symmetry. This paper will describe the sequence of keyhole, 1DConA, 2DConA, and Symcap experiments we performed over the last year to tune the PSS implosions. We were successful in achieving our design goals; the PSS is the fastest CH capsule implosion in the laboratory, with peak velocity 400 μm, a round hot-spot, with hotspot P2 = 0 within errors, and a hot-spot ion temperature 3.5 keV. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

Unintentional force changes in cyclical tasks performed by an abundant system: Empirical observations and a dynamical model.

PubMed

Reschechtko, Sasha; Hasanbarani, Fariba; Akulin, Vladimir M; Latash, Mark L

2017-05-14

The study explored unintentional force changes elicited by removing visual feedback during cyclical, two-finger isometric force production tasks. Subjects performed two types of tasks at 1Hz, paced by an auditory metronome. One - Force task - required cyclical changes in total force while maintaining the sharing, defined as relative contribution of a finger to total force. The other task - Share task - required cyclical changes in sharing while keeping total force unchanged. Each trial started under full visual feedback on both force and sharing; subsequently, feedback on the variable that was instructed to stay constant was frozen, and finally feedback on the other variable was also removed. In both tasks, turning off visual feedback on total force elicited a drop in the mid-point of the force cycle and an increase in the peak-to-peak force amplitude. Turning off visual feedback on sharing led to a drift of mean share toward 50:50 across both tasks. Without visual feedback there was consistent deviation of the two force time series from the in-phase pattern (typical of the Force task) and from the out-of-phase pattern (typical of the Share task). This finding is in contrast to most earlier studies that demonstrated only two stable patterns, in-phase and out-of-phase. We interpret the results as consequences of drifts of parameters in a dynamical system leading in particular to drifts in the referent finger coordinates toward their actual coordinates. The relative phase desynchronization is caused by the right-left differences in the hypothesized drift processes, consistent with the dynamic dominance hypothesis. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Three-dimensional assessment of postural tremor during goal-directed aiming.

PubMed

Kelleran, K J; Morrison, S; Russell, D M

2016-12-01

The performance of fine motor tasks which require a degree of precision can be negatively affected by physiological tremor. This study examined the effect of different aiming positions on anterior-posterior (AP), medial-lateral (ML) and vertical (VT) postural tremor. Participants were required to aim a mock handgun at a target located in front of them at eye level. Changes in AP, ML and VT tremor from the forearm and gun barrel were assessed as a function of limb (i.e., whether one or both arms were used) and upper arm position (elbow bent or extended). Tremor was recorded using triaxial accelerometers. Results showed that, across all tasks, the ML and VT tremor for any point was characterized by two frequency peaks (between 1-4 and 8-12 Hz) with amplitude increasing from proximal (forearm) to distal (gun barrel). Interestingly, irrespective of the posture adopted, ML accelerations were of greater amplitude than VT oscillations. AP oscillations were markedly smaller compared to VT and ML tremor, did not display consistent frequency peaks, and were not altered by the arm conditions. Altering the aiming posture resulted in changes in VT and ML tremor amplitude, with oscillations being greater when using a single arm as compared to when two arms were used together. Similarly, tremor amplitude was reduced when the task was performed with the elbow bent compared to the straight arm condition. Overall, these results highlight that ML oscillations make as significant a contribution to the overall tremor dynamics as those observed in the VT direction. However, the origin of ML tremor is not simply the product of voluntary adjustments to maintain aim on the target, but also exhibits features similar to the neural generated 8-12-Hz tremor seen under postural conditions.

Seasonal influence on adherence to and effects of an interval walking training program on sedentary female college students in Japan

NASA Astrophysics Data System (ADS)

Tanabe, Aiko; Masuki, Shizue; Nemoto, Ken-ichi; Nose, Hiroshi

2017-11-01

Habitual exercise training is recommended to young people for their health promotion, but adherence may be influenced by atmospheric temperature (T a ) if performed outdoors. We compared the adherence to and the effects of a home-based interval walking training (IWT) program on sedentary female college students between winter and summer. For summer training over 176 days, 48 subjects (18-22 years old) were randomly divided into two groups: the control group (CNTsummer, n = 24), which maintained a sedentary lifestyle as before, and the IWT group (IWTsummer, n = 24), which performed IWT while energy expenditure was monitored by accelerometry. For winter training over 133 days, another group of 47 subjects (18-24 years old) was randomly divided into CNTwinter (n = 24) and IWTwinter (n = 23), as in summer. The peak T a per day was 26 ± 6 °C (SD) (range of 9-35 °C) in summer, much higher than 7 ± 5 °C (range of - 3-20 °C) in winter (P < 0.001). During a 50-day vacation period, participants walked 2.1 ± 0.3 (SE) days/week in IWTsummer, less than 4.2 ± 0.3 days/week in IWTwinter (P < 0.001), with half of the energy expenditure/week for fast walking during the winter vacation (P < 0.02), whereas both IWT groups walked 2 days/week during a school period (P > 0.8). After training, the peak aerobic capacity and knee flexion force increased in IWTwinter (P < 0.01) but not in CNTwinter (P > 0.3). Conversely, these parameters decreased in the summer groups. Thus, the adherence to and effects of IWT on sedentary female college students in Japan decreased in summer at least partially due to a high T a .

Unintentional force changes in cyclical tasks performed by an abundant system: Empirical observations and a dynamical model

PubMed Central

Reschechtko, Sasha; Hasanbarani, Fariba; Akulin, Vladimir M.; Latash, Mark L.

2017-01-01

The study explored unintentional force changes elicited by removing visual feedback during cyclical, two-finger isometric force production tasks. Subjects performed two types of tasks at 1 Hz, paced by an auditory metronome. One – Force task – required cyclical changes in total force while maintaining the sharing, defined as relative contribution of a finger to total force. The other task – Share task – required cyclical changes in sharing while keeping total force unchanged. Each trial started under full visual feedback on both force and sharing; subsequently, feedback on the variable that was instructed to stay constant was frozen, and finally feedback on the other variable was also removed. In both tasks, turning off visual feedback on total force elicited a drop in the mid-point of the force cycle and an increase in the peak-to-peak force amplitude. Turning off visual feedback on sharing led to a drift of mean share toward 50:50 across both tasks. Without visual feedback there was consistent deviation of the two force time series from the in-phase pattern (typical of the Force task) and from the out-of-phase pattern (typical of the Share task). This finding is in contrast to most earlier studies that demonstrated only two stable patterns, in-phase and out-of-phase. We interpret the results as consequences of drifts of parameters in a dynamical system leading in particular to drifts in the referent finger coordinates toward their actual coordinates. The relative phase desynchronization is caused by the right-left differences in the hypothesized drift processes, consistent with the dynamic dominance hypothesis. PMID:28344070

[HPLC-fingerprint-based quality evaluation on a Tibetan medicine Phyllanthus emblica and its tannin parts].

PubMed

Sun, Xue-Fei; Zhang, Hong-Yan; Xia, Qing; Zhao, Hai-Juan; Wu, Ling-Fang; Zhang, Lan-Zhen; Shi, Ren-Bing

2014-04-01

This study is to establish the fingerprint for Phyllanthus emblica and their tannin parts from different habitats by HPLC for its quality control. The determination was carried out on a Diamonsil C18 (4.6 mm x 250 mm, 5 microm) column, with methanol-0.2% glacial acetic acid as mobile phase with gradient elution at a flow rate of 1 mL x min(-1). The temperature was maintained at 30 degrees C and the detected wavelength is 260 nm, Thirteen chromatographic peaks were extracted as the common peaks of the fingerprint of P. emblica, and eleven as the common peaks of P. emblica tannin parts, and five peaks were identified by comparing with referent samples. The fingerprints of 8 samples were compared and classified by similarity evaluation, cluster analysis and principal component analysis (PCA). The similarity degrees of eight P. emblica were between 0.763 and 0.993, while tannin parts were between 0.903 and 0.991. All the samples of P. emblica and their tannin parts were classified into 3 categories. The method was so highly reproducible, simple and reliable that it could provide basis for quality control and evaluation of P. emblica from different habitats.

A new fold-cross metal mesh filter for suppressing side lobe leakage in terahertz region

NASA Astrophysics Data System (ADS)

Lu, Changgui; Qi, Zhengqing; Guo, Wengao; Cui, Yiping

2018-04-01

In this paper we propose a new type of fold-cross metal mesh band pass filter, which keeps diffraction side lobe far away from the main transmission peak and shows much better side lobe suppression. Both experimental and theoretical studies are made to analyze the mechanism of side lobe. Compared to the traditional cross filter, the fold-cross filter has a much lower side lobe with almost the same central frequency, bandwidth and highest transmission about 98%. Using the photolithography and electroplating techniques, we experimentally extend the distance between the main peak and diffraction side lobe to larger than 1 THz for the fold-cross filter, which is two times larger than the cross filter while maintaining the main peak transmissions of 89% at 1.25 THz for the two structures. This type of single layer substrate-free fold-cross metal structure shows better design flexibility and structure reliability with the introduction of fold arms for metal mesh band pass filters.

Method and apparatus for signal processing in a sensor system for use in spectroscopy

DOEpatents

O'Connor, Paul [Bellport, NY; DeGeronimo, Gianluigi [Nesconset, NY; Grosholz, Joseph [Natrona Heights, PA

2008-05-27

A method for processing pulses arriving randomly in time on at least one channel using multiple peak detectors includes asynchronously selecting a non-busy peak detector (PD) in response to a pulse-generated trigger signal, connecting the channel to the selected PD in response to the trigger signal, and detecting a pulse peak amplitude. Amplitude and time of arrival data are output in first-in first-out (FIFO) sequence. An apparatus includes trigger comparators to generate the trigger signal for the pulse-receiving channel, PDs, a switch for connecting the channel to the selected PD, and logic circuitry which maintains the write pointer. Also included, time-to-amplitude converters (TACs) convert time of arrival to analog voltage and an analog multiplexer provides FIFO output. A multi-element sensor system for spectroscopy includes detector elements, channels, trigger comparators, PDs, a switch, and a logic circuit with asynchronous write pointer. The system includes TACs, a multiplexer and analog-to-digital converter.

Cruise noise of the 2/9th scale model of the Large-scale Advanced Propfan (LAP) propeller, SR-7A

NASA Technical Reports Server (NTRS)

Dittmar, James H.; Stang, David B.

1987-01-01

Noise data on the Large-scale Advanced Propfan (LAP) propeller model SR-7A were taken in the NASA Lewis Research Center 8 x 6 foot Wind Tunnel. The maximum blade passing tone noise first rises with increasing helical tip Mach number to a peak level, then remains the same or decreases from its peak level when going to higher helical tip Mach numbers. This trend was observed for operation at both constant advance ratio and approximately equal thrust. This noise reduction or, leveling out at high helical tip Mach numbers, points to the use of higher propeller tip speeds as a possible method to limit airplane cabin noise while maintaining high flight speed and efficiency. Projections of the tunnel model data are made to the full scale LAP propeller mounted on the test bed aircraft and compared with predictions. The prediction method is found to be somewhat conservative in that it slightly overpredicts the projected model data at the peak.

Cruise noise of the 2/9 scale model of the Large-scale Advanced Propfan (LAP) propeller, SR-7A

NASA Technical Reports Server (NTRS)

Dittmar, James H.; Stang, David B.

1987-01-01

Noise data on the Large-scale Advanced Propfan (LAP) propeller model SR-7A were taken in the NASA Lewis Research Center 8 x 6 foot Wind Tunnel. The maximum blade passing tone noise first rises with increasing helical tip Mach number to a peak level, then remains the same or decreases from its peak level when going to higher helical tip Mach numbers. This trend was observed for operation at both constant advance ratio and approximately equal thrust. This noise reduction or, leveling out at high helical tip Mach numbers, points to the use of higher propeller tip speeds as a possible method to limit airplane cabin noise while maintaining high flight speed and efficiency. Projections of the tunnel model data are made to the full scale LAP propeller mounted on the test bed aircraft and compared with predictions. The prediction method is found to be somewhat conservative in that it slightly overpredicts the projected model data at the peak.

Daily patterns of synchrony in lying and feeding of cows: Quasi-natural state and (anti-) synchrony factors.

PubMed

Flury, Rebekka; Gygax, Lorenz

2016-12-01

Synchrony is thought to provide fitness advantages to group-living animals, but little is known how animals maintain synchrony. We investigated intensity of synchrony factors (milking, feed-provision) in cattle herds. Intensity decreased from dairy cows milked in a parlour to cows milked by a robot to suckler cows raising calves. On 30 farms, 10 of each type, we recorded synchrony in lying and feeding. Peaks in lying synchronously were visible in the early morning, around noon, and late at night. These peaks decreased from the suckler cows to the cows milked in a parlour and to the cows milked by a robot. Complementary peaks were found for synchronous feeding. The asynchronous milking times with the milking robot decreased synchrony. Unexpectedly, the suckler cows with the weakest synchrony factors also showed a high level of synchrony. These results indicate that internal motivations for synchrony may be present in addition to external synchrony factors. Copyright © 2016 Elsevier B.V. All rights reserved.

49 CFR 18.36 - Procurement.

Code of Federal Regulations, 2014 CFR

2014-10-01

... subgrantees will maintain a contract administration system which ensures that contractors perform in... and subgrantees will maintain a written code of standards of conduct governing the performance of... resources. (9) Grantees and subgrantees will maintain records sufficient to detail the significant history...

34 CFR 80.36 - Procurement.

Code of Federal Regulations, 2014 CFR

2014-07-01

... subgrantees will maintain a contract administration system which ensures that contractors perform in... and subgrantees will maintain a written code of standards of conduct governing the performance of... resources. (9) Grantees and subgrantees will maintain records sufficient to detail the significant history...

Residential load management system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uhr, C.W.

1986-03-01

The MAX load management system marketed by the UHR Corporation is described. The system completely replaces conventional heating, cooling, and hot water equipment. It is designed to reduce significantly the home's peak demand during the electric utility's system-wide peak load periods while at the same time maintain the homeowner's comfort. The integration of microprocessor, thermal storage, and heat pump technologies allows for broad flexibility in terms of tailoring the system to a specific electric utility's needs. Twelve pilot systems installed in Northern Virginia outside of Washington, DC have been operational since early 1985. The test results to date have confirmedmore » both the system's load management capability and its comfort improvement characteristics. The fundamental characteristics and hardware for the system are described. 9 figures.« less

Impedance self-matching ultra-narrow linewidth fiber resonator by use of a tunable π-phase-shifted FBG.

PubMed

Jing, Mingyong; Yu, Bo; Hu, Jianyong; Hou, Huifang; Zhang, Guofeng; Xiao, Liantuan; Jia, Suotang

2017-05-15

In this paper, we present a novel ultra-narrow linewidth fiber resonator formed by a tunable polarization maintaining (PM) π-phase-shifted fiber Bragg grating and a PM uniform fiber Bragg grating with a certain length of PM single mode fiber patch cable between them. Theoretical prediction shows that this resonator has ultra-narrow linewidth resonant peaks and is easy to realize impedance matching. We experimentally obtain 3 MHz narrow linewidth impedance matched resonant peak in a 7.3 m ultra-long passive fiber cavity. The impedance self-matching characteristic of this resonator also makes itself particularly suitable for use in ultra-sensitive sensors, ultra-narrow band rejection optical filters and fiber lasers applications.

Optimization of an underwater in-situ LaBr3:Ce spectrometer with energy self-calibration and efficiency calibration.

PubMed

Zeng, Zhi; Pan, Xingyu; Ma, Hao; He, Jianhua; Cang, Jirong; Zeng, Ming; Mi, Yuhao; Cheng, Jianping

2017-03-01

An underwater in-situ gamma-ray spectrometer based on LaBr 3 :Ce was developed and optimized to monitor marine radioactivity. The intrinsic background mainly from 138 La and 227 Ac of LaBr 3 :Ce was well determined by low background measurement and pulse shape discrimination method. A method of self-calibration using three internal contaminant peaks was proposed to eliminate the peak shift during long-term monitoring. With experiments under different temperatures, the method was proved to be helpful for maintaining long-term stability. To monitor the marine radioactivity, the spectrometer's efficiency was calculated via water tank experiment as well as Monte Carlo simulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maximizing performance in supercritical fluid chromatography using low-density mobile phases.

PubMed

Gritti, Fabrice; Fogwill, Michael; Gilar, Martin; Jarrell, Joseph A

2016-10-14

The performance of a 3.0mm×150mm column packed with 1.8μm fully porous HSS-SB-C 18 particles was investigated in supercritical fluid chromatography (SFC) with low-density, highly expansible carbon dioxide. These conditions are selected for the analysis of semi-volatile compounds. Elevated temperatures (>100°C) were then combined with low column back pressures (<100bar). In this work, the inlet temperature of pure carbon dioxide was set at 107°C, the active back pressure regulator (ABPR) pressure was fixed at 100bar, and the flow rate was set at 2.1mL/min at 12°C (liquefied carbon dioxide) and at an inlet column pressure close to 300bar. Nine n-alkylbenzenes (from benzene to octadecylbenzene) were injected under linear (no sample overload) conditions. The severe steepness of the temperature gradients across the column diameter were predicted from a simplified heat transfer model. Such conditions dramatically lower the column performance by affecting the symmetry of the peak shape. In order to cope with this problem, three different approaches were experimentally tested. They include (1) the decoupling and the proper selection of the inlet eluent temperature with respect to the oven temperature, (2) the partial thermal insulation of the column using polyethylene aerogel, and (3) the application of a high vacuum (10 -5 Torr provided by a turbo-molecular pump) in a housing chamber surrounding the whole column body. The results reveal that (1) the column efficiency can be maximized by properly selecting the difference between the eluent and the oven temperatures, (2) the mere wrapping of the column with an excellent insulating material is insufficient to fully eliminate heat exchanges by conduction and the undesirable radial density gradients across the column i.d., and (3) the complete thermal insulation of the SFC column under high vacuum allows to maximize the column efficiency by maintaining the integrity of the peak shape. Copyright © 2016 Elsevier B.V. All rights reserved.

Difference in peak weight transfer and timing based on golf handicap.

PubMed

Queen, Robin M; Butler, Robert J; Dai, Boyi; Barnes, C Lowry

2013-09-01

Weight shift during the golf swing has been a topic of discussion among golf professionals; however, it is still unclear how weight shift varies in golfers of different performance levels. The main purpose of this study was to examine the following: (a) the changes in the peak ground reaction forces (GRF) and the timing of these events between high (HHCP) and low handicap (LHCP) golfers and (b) the differences between the leading and trailing legs. Twenty-eight male golfers were recruited and divided based on having an LHCP < 9 or HHCP > 9. Three-dimensional GRF peaks and the timing of the peaks were recorded bilaterally during a golf swing. The golf swing was divided into different phases: (a) address to the top of the backswing, (b) top of the backswing to ball contact, and (c) ball contact to the end of follow through. Repeated measures analyses of variance (α = 0.05) were completed for each study variable: the magnitude and the timing of peak vertical GRF, peak lateral GRF, and peak medial GRF (α = 0.05). The LHCP group had a greater transfer of vertical force from the trailing foot to the leading foot in phase 2 than the HHCP group. The LHCP group also demonstrated earlier timing of peak vertical force throughout the golf swing than the HHCP group. The LHCP and HHCP groups demonstrated different magnitudes of peak lateral force. The LHCP group had an earlier timing of peak lateral GRF in phase 2 and earlier timing of peak medial GRF in phases 1 and 2 than the HHCP group. In general, LHCP golfers demonstrated greater and earlier force generation than HHCP golfers. It may be relevant to consider both the magnitude of the forces and the timing of these events during golf-specific training to improve performance. These data reveal weight shifting differences that can be addressed by teaching professionals to help their students better understand weight transfer during the golf swing to optimize performance.

Helical Fiber Amplifier

DOEpatents

Koplow, Jeffrey P.; Kliner, Dahy; Goldberg, Lew

2002-12-17

A multi-mode gain fiber is provided which affords substantial improvements in the maximum pulse energy, peak power handling capabilities, average output power, and/or pumping efficiency of fiber amplifier and laser sources while maintaining good beam quality (comparable to that of a conventional single-mode fiber source). These benefits are realized by coiling the multimode gain fiber to induce significant bend loss for all but the lowest-order mode(s).

Experimental Investigation of a Morphing Nacelle Ducted Fan

NASA Technical Reports Server (NTRS)

Kondor, Shayne A.; Moore, Mark

2005-01-01

The application of Circulation Control to the nacelle of a shrouded fan is proposed as a means to enhance off-design performance of the shrouded fan. Typically, a fixed geometry shroud is efficient at a single operating condition. Modifying circulation about the fixed geometry is proposed as a means to virtually morph the shroud without moving surfaces. This approach will enhance off-design-point performance with minimal complexity, weight, and cost. Termed the Morphing Nacelle, this concept provides an attractive propulsion option for Vertical Take-off and Landing (VTOL) aircraft, such conceptual Personal Air Vehicle (PAV) configurations proposed by NASA. An experimental proof of concept investigation of the Morphing Nacelle is detailed in this paper. A powered model shrouded fan model was constructed with Circulation Control (CC) devices integrated in the inlet and exit of the nacelle. Both CC devices consisted of an annular jet slot directing a jet sheet tangent to a curved surface, generally described as a Coanda surface. The model shroud was tailored for axial flight, with a diffusing inlet, but was operated off-design condition as a static lifting fan. Thrust stand experiments were conducted to determine if the CC devices could effectively improve off-design performance of the shrouded fan. Additional tests were conducted to explore the effectiveness of the CC devices a means to reduce peak static pressure on the ground below a lifting fan. Experimental results showed that off-design static thrust performance of the model was improved when the CC devices were employed under certain conditions. The exhaust CC device alone, while effective in diffusing the fan exhaust and improving weight flow into shroud inlet, tended to diminish performance of the fan with increased CC jet momentum. The inlet CC device was effective at reattaching a normally stalled inlet flow condition, proving an effective means of enhancing performance. A more dramatic improvement in static thrust was obtained when the inlet and exit CC devices were operated in unison, but only over a limited range of CC jet momentum. Operating the nacelle inlet and exit CC devices together proved very effective in reducing peak ground plane static pressure, while maintaining static thrust. The Morphing Nacelle concept proved effective at enhancing off-design performance of the model; however, additional investigation is necessary to generalize the results.

Power optimization of digital baseband WCDMA receiver components on algorithmic and architectural level

NASA Astrophysics Data System (ADS)

Schämann, M.; Bücker, M.; Hessel, S.; Langmann, U.

2008-05-01

High data rates combined with high mobility represent a challenge for the design of cellular devices. Advanced algorithms are required which result in higher complexity, more chip area and increased power consumption. However, this contrasts to the limited power supply of mobile devices. This presentation discusses the application of an HSDPA receiver which has been optimized regarding power consumption with the focus on the algorithmic and architectural level. On algorithmic level the Rake combiner, Prefilter-Rake equalizer and MMSE equalizer are compared regarding their BER performance. Both equalizer approaches provide a significant increase of performance for high data rates compared to the Rake combiner which is commonly used for lower data rates. For both equalizer approaches several adaptive algorithms are available which differ in complexity and convergence properties. To identify the algorithm which achieves the required performance with the lowest power consumption the algorithms have been investigated using SystemC models regarding their performance and arithmetic complexity. Additionally, for the Prefilter Rake equalizer the power estimations of a modified Griffith (LMS) and a Levinson (RLS) algorithm have been compared with the tool ORINOCO supplied by ChipVision. The accuracy of this tool has been verified with a scalable architecture of the UMTS channel estimation described both in SystemC and VHDL targeting a 130 nm CMOS standard cell library. An architecture combining all three approaches combined with an adaptive control unit is presented. The control unit monitors the current condition of the propagation channel and adjusts parameters for the receiver like filter size and oversampling ratio to minimize the power consumption while maintaining the required performance. The optimization strategies result in a reduction of the number of arithmetic operations up to 70% for single components which leads to an estimated power reduction of up to 40% while the BER performance is not affected. This work utilizes SystemC and ORINOCO for the first estimation of power consumption in an early step of the design flow. Thereby algorithms can be compared in different operating modes including the effects of control units. Here an algorithm having higher peak complexity and power consumption but providing more flexibility showed less consumption for normal operating modes compared to the algorithm which is optimized for peak performance.

Method of wavefront tilt correction for optical heterodyne detection systems under strong turbulence

NASA Astrophysics Data System (ADS)

Xiang, Jing-song; Tian, Xin; Pan, Le-chun

2014-07-01

Atmospheric turbulence decreases the heterodyne mixing efficiency of the optical heterodyne detection systems. Wavefront tilt correction is often used to improve the optical heterodyne mixing efficiency. But the performance of traditional centroid tracking tilt correction is poor under strong turbulence conditions. In this paper, a tilt correction method which tracking the peak value of laser spot on focal plane is proposed. Simulation results show that, under strong turbulence conditions, the performance of peak value tracking tilt correction is distinctly better than that of traditional centroid tracking tilt correction method, and the phenomenon of large antenna's performance inferior to small antenna's performance which may be occurred in centroid tracking tilt correction method can also be avoid in peak value tracking tilt correction method.

A compact high-resolution X-ray ion mobility spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinecke, T.; Kirk, A. T.; Heptner, A.

For the ionization of gaseous samples, most ion mobility spectrometers employ radioactive ionization sources, e.g., containing {sup 63}Ni or {sup 3}H. Besides legal restrictions, radioactive materials have the disadvantage of a constant radiation with predetermined intensity. In this work, we replaced the {sup 3}H source of our previously described high-resolution ion mobility spectrometer with 75 mm drift tube length with a commercially available X-ray source. It is shown that the current configuration maintains the resolving power of R = 100 which was reported for the original setup containing a {sup 3}H source. The main advantage of an X-ray source ismore » that the intensity of the radiation can be adjusted by varying its operating parameters, i.e., filament current and acceleration voltage. At the expense of reduced resolving power, the sensitivity of the setup can be increased by increasing the activity of the source. Therefore, the performance of the setup can be adjusted to the specific requirements of any application. To investigate the relation between operating parameters of the X-Ray source and the performance of the ion mobility spectrometer, parametric studies of filament current and acceleration voltage are performed and the influence on resolving power, peak height, and noise is analyzed.« less

Method and system for calibrating acquired spectra for use in spectral analysis

DOEpatents

Reber, Edward L.; Rohde, Kenneth W.; Blackwood, Larry G.

2010-09-14

A method for calibrating acquired spectra for use in spectral analysis includes performing Gaussian peak fitting to spectra acquired by a plurality of NaI detectors to define peak regions. A Na and annihilation doublet may be located among the peak regions. A predetermined energy level may be applied to one of the peaks in the doublet and a location of a hydrogen peak may be predicted based on the location of at least one of the peaks of the doublet. Control systems for calibrating spectra are also disclosed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guiochon, Georges A; Shalliker, R. Andrew

An algorithm was developed for 2DHPLC that automated the process of peak recognition, measuring their retention times, and then subsequently plotting the information in a two-dimensional retention plane. Following the recognition of peaks, the software then performed a series of statistical assessments of the separation performance, measuring for example, correlation between dimensions, peak capacity and the percentage of usage of the separation space. Peak recognition was achieved by interpreting the first and second derivatives of each respective one-dimensional chromatogram to determine the 1D retention times of each solute and then compiling these retention times for each respective fraction 'cut'. Duemore » to the nature of comprehensive 2DHPLC adjacent cut fractions may contain peaks common to more than one cut fraction. The algorithm determined which components were common in adjacent cuts and subsequently calculated the peak maximum profile by interpolating the space between adjacent peaks. This algorithm was applied to the analysis of a two-dimensional separation of an apple flesh extract separated in a first dimension comprising a cyano stationary phase and an aqueous/THF mobile phase as the first dimension and a second dimension comprising C18-Hydro with an aqueous/MeOH mobile phase. A total of 187 peaks were detected.« less

Inner chromatogram projection (ICP) for resolution of GC-MS data with embedded chromatographic peaks.

PubMed

Wang, Zhi-Guo; Chen, Zeng-Ping; Gong, Fan; Wu, Hai-Long; Yu, Ru-Qin

2002-05-01

The chromatographic peak located inside another peak in the time direction is called an embedded or inner peak in contradistinction with the embedding peak, which is called an outer peak. The chemical components corresponding to inner and outer peaks are called inner and outer components, respectively. This special case of co-eluting chromatograms was investigated using chemometric approaches taking GC-MS as an example. A novel method, named inner chromatogram projection (ICP), for resolution of GC-MS data with embedded chromatographic peaks is derived. Orthogonal projection resolution is first utilized to obtain the chromatographic profile of the inner component. Projection of the two-way data matrix columnwise-normalized along the time direction to the normalized profile of the inner component found is subsequently performed to find the selective m/z points, if they exist, which represent the chromatogram of the outer component by itself. With the profiles obtained, the mass spectra can easily be found by means of a least-squares procedure. The results for both simulated data and real samples demonstrate that the proposed method is capable of achieving satisfactory resolution performance not affected by the shapes of chromatograms and the relative positions of the components involved.

Age and measurement time-of-day effects on speech recognition in noise.

PubMed

Veneman, Carrie E; Gordon-Salant, Sandra; Matthews, Lois J; Dubno, Judy R

2013-01-01

The purpose of this study was to determine the effect of measurement time of day on speech recognition in noise and the extent to which time-of-day effects differ with age. Older adults tend to have more difficulty understanding speech in noise than younger adults, even when hearing is normal. Two possible contributors to this age difference in speech recognition may be measurement time of day and inhibition. Most younger adults are "evening-type," showing peak circadian arousal in the evening, whereas most older adults are "morning-type," with circadian arousal peaking in the morning. Tasks that require inhibition of irrelevant information have been shown to be affected by measurement time of day, with maximum performance attained at one's peak time of day. The authors hypothesized that a change in inhibition will be associated with measurement time of day and therefore affect speech recognition in noise, with better performance in the morning for older adults and in the evening for younger adults. Fifteen younger evening-type adults (20-28 years) and 15 older morning-type adults with normal hearing (66-78 years) listened to the Hearing in Noise Test (HINT) and the Quick Speech in Noise (QuickSIN) test in the morning and evening (peak and off-peak times). Time of day preference was assessed using the Morningness-Eveningness Questionnaire. Sentences and noise were presented binaurally through insert earphones. During morning and evening sessions, participants solved word-association problems within the visual-distraction task (VDT), which was used as an estimate of inhibition. After each session, participants rated perceived mental demand of the tasks using a revised version of the NASA Task Load Index. Younger adults performed significantly better on the speech-in-noise tasks and rated themselves as requiring significantly less mental demand when tested at their peak (evening) than off-peak (morning) time of day. In contrast, time-of-day effects were not observed for the older adults on the speech recognition or rating tasks. Although older adults required significantly more advantageous signal-to-noise ratios than younger adults for equivalent speech-recognition performance, a significantly larger younger versus older age difference in speech recognition was observed in the evening than in the morning. Older adults performed significantly poorer than younger adults on the VDT, but performance was not affected by measurement time of day. VDT performance for misleading distracter items was significantly correlated with HINT and QuickSIN test performance at the peak measurement time of day. Although all participants had normal hearing, speech recognition in noise was significantly poorer for older than younger adults, with larger age-related differences in the evening (an off-peak time for older adults) than in the morning. The significant effect of measurement time of day suggests that this factor may impact the clinical assessment of speech recognition in noise for all individuals. It appears that inhibition, as estimated by a visual distraction task for misleading visual items, is a cognitive mechanism that is related to speech-recognition performance in noise, at least at a listener's peak time of day.

Feasibility of cardiopulmonary exercise testing and training using a robotics-assisted tilt table in dependent-ambulatory stroke patients.

PubMed

Saengsuwan, Jittima; Huber, Celine; Schreiber, Jonathan; Schuster-Amft, Corina; Nef, Tobias; Hunt, Kenneth J

2015-09-26

We evaluated the feasibility of an augmented robotics-assisted tilt table (RATT) for incremental cardiopulmonary exercise testing (CPET) and exercise training in dependent-ambulatory stroke patients. Stroke patients (Functional Ambulation Category ≤ 3) underwent familiarization, an incremental exercise test (IET) and a constant load test (CLT) on separate days. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and real-time visual feedback to guide the exercise work rate was used. Feasibility assessment considered technical feasibility, patient tolerability, and cardiopulmonary responsiveness. Eight patients (4 female) aged 58.3 ± 9.2 years (mean ± SD) were recruited and all completed the study. For IETs, peak oxygen uptake (V'O2peak), peak heart rate (HRpeak) and peak work rate (WRpeak) were 11.9 ± 4.0 ml/kg/min (45 % of predicted V'O2max), 117 ± 32 beats/min (72 % of predicted HRmax) and 22.5 ± 13.0 W, respectively. Peak ratings of perceived exertion (RPE) were on the range "hard" to "very hard". All 8 patients reached their limit of functional capacity in terms of either their cardiopulmonary or neuromuscular performance. A ventilatory threshold (VT) was identified in 7 patients and a respiratory compensation point (RCP) in 6 patients: mean V'O2 at VT and RCP was 8.9 and 10.7 ml/kg/min, respectively, which represent 75 % (VT) and 85 % (RCP) of mean V'O2peak. Incremental CPET provided sufficient information to satisfy the responsiveness criteria and identification of key outcomes in all 8 patients. For CLTs, mean steady-state V'O2 was 6.9 ml/kg/min (49 % of V'O2 reserve), mean HR was 90 beats/min (56 % of HRmax), RPEs were > 2, and all patients maintained the active work rate for 10 min: these values meet recommended intensity levels for bouts of training. The augmented RATT is deemed feasible for incremental cardiopulmonary exercise testing and exercise training in dependent-ambulatory stroke patients: the approach was found to be technically implementable, acceptable to the patients, and it showed substantial cardiopulmonary responsiveness. This work has clinical implications for patients with severe disability who otherwise are not able to be tested.

Preparative Isolation and Purification of Flavone C-Glycosides from the Leaves of Ficus microcarpa L. f by Medium-Pressure Liquid Chromatography, High-Speed Countercurrent Chromatography, and Preparative Liquid Chromatography

PubMed Central

Wang, Xiaohong; Liang, Yong; Zhu, Licai; Xie, Huichun; Li, Hang; He, Junting; Pan, Man; Zhang, Tianyou; Ito, Yoichiro

2009-01-01

Combined with medium-pressure liquid chromatography (MPLC) and preparative high-performance liquid chromatography (perp-HPLC), high-speed countercurrent chromatography (HSCCC) was applied for separation and purification of flavone C-glycosides from the crude extract of leaves of Ficus microcarpae L. f. HSCCC separation was performed on a two-phase solvent system composed of methyl tert- butyl ether - ethyl acetate – 1-butanol – acetonitrile – 0.1% aqueous trifluoroacetic acid at a volume ratio of 1:3:1:1:5. Partially resolved peak fractions from HSCCC separation were further purified by preparative HPLC. Four well-separated compounds were obtained and their purities were determined by HPLC. The purities of these peaks were 97.28%, 97.20%, 92.23%, and 98.40%.. These peaks were characterized by ESI-MSn. According to the reference, they were identified as orientin (peak I), isovitexin-3″-O-glucopyranoside (peak II), isovitexin (peak III), and vitexin (peak IV), yielded 1.2 mg, 4.5 mg, 3.3 mg, and 1.8 mg, respectively. PMID:20190866

Combination of body mass-based resistance training and high-intensity walking can improve both muscle size and V˙O2 peak in untrained older women.

PubMed

Ozaki, Hayao; Kitada, Tomoharu; Nakagata, Takashi; Naito, Hisashi

2017-05-01

Here, we aimed to compare the effect of a combination of body mass-based resistance exercise and moderate-intensity (55% peak oxygen uptake [ V˙O 2 peak]) walking or high-intensity (75% V˙O 2 peak) walking on muscle size and V˙O 2 peak in untrained older women. A total of 12 untrained older women (mean age 60 ± 2 years) were randomly assigned to either a moderate-intensity aerobic training group (n = 6) or high-intensity aerobic training group (n = 6). Both groups carried out body-mass based (lower body) resistance exercises (2 sets of 10 repetitions) on 3 days/week for 8 weeks. Between these exercises, the participants in the moderate-intensity aerobic training group walked at a previously determined speed equivalent to 55% V˙O 2 peak, whereas those in the high-intensity aerobic training group walked at a speed equivalent to 75% V˙O 2 peak. Muscle thickness of the anterior aspect of the thigh and maximal isokinetic knee extension strength significantly increased in both groups (P < 0.01); these relative changes were negatively correlated with the absolute muscle thickness of the anterior aspect of the thigh value and the relative value of maximal knee strength to body mass at pre-intervention, respectively. A significant group × time interaction was noted for V˙O 2 peak (P < 0.05), which increased only in the high-intensity aerobic training group. Body mass-based resistance training significantly induced muscle hypertrophy in untrained older women. In particular, lower muscle thickness before intervention was associated with greater training-induced growth. Furthermore, V˙O 2 peak can be increased by combined circuit training involving low-load resistance exercise and walking, particularly when a relatively high intensity of walking is maintained. Geriatr Gerontol Int 2017; 17: 779-784. © 2016 Japan Geriatrics Society.

The effect of maturation on adaptations to strength training and detraining in 11-15-year-olds.

PubMed

Meylan, C M P; Cronin, J B; Oliver, J L; Hopkins, W G; Contreras, B

2014-06-01

To investigate how maturity status modifies the effects of strength training and detraining on performance, we subjected 33 young men to 8 weeks of strength training twice per week followed by 8 weeks without training. Changes in performance tests were analyzed in three maturity groups based on years from/to age of predicted peak height velocity (PHV): pre-PHV (-1.7 ± 0.4 years; n = 10), mid-PHV (-0.2 ± 0.4 years; n = 11), and post-PHV (1.0 ± 0.4 years; n = 12). Mean training effects on one repetition maximum strength (3.6-10.0%), maximum explosive power (11-20%), jump length (6.5-7.4%), and sprint times (-2.1% to -4.7%) ranged from small to large, with generally greater changes in mid- and post-PHV groups. Changes in force-velocity relationships reflected generally greater increases in strength at faster velocities. In the detraining period, the pre-PHV group showed greatest loss of strength and power, the post-PHV group showed some loss of sprint performance, but all groups maintained or improved jump length. Strength training was thus generally less effective before the growth spurt. Maintenance programs are needed for most aspects of explosive performance following strength training before the growth spurt and for sprint speed after the growth spurt. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of Walking Speed and Visual-Target Distance on Toe Trajectory During Swing Phase

NASA Technical Reports Server (NTRS)

Miller, Chris; Peters, Brian; Brady, Rachel; Warren, Liz; Richards, Jason; Mulavara, Ajitkumar; Sung, Hsi-Guang; Bloomberg, Jacob

2006-01-01

After spaceflight, astronauts experience disturbances in their ability to walk and maintain postural stability (Bloomberg, et al., 1997). One of the post-flight neurovestibular assessments requires that the astronaut walk on a treadmill at 1.8 m/sec (4.0 mph), while performing a visual acuity test, set at two different distances ( far and near ). For the first few days after landing, some crewmembers can not maintain the required pace, so a lower speed may be used. The slower velocity must be considered in the kinematic analysis, because Andriacchi, et al. (1977) showed that in clinical populations, changes in gait parameters may be attributable more to slower gait speed than pathology. Studying toe trajectory gives a global view of control of the leg, since it involves coordination of muscles and joints in both the swing and stance legs (Karst, et al., 1999). Winter (1992) and Murray, et al. (1984) reported that toe clearance during overground walking increased slightly as speed increased, but not significantly. Also, toe vertical peaks in both early and late swing phase did increase significantly with increasing speed. During conventional testing of overground locomotion, subjects are usually asked to fix their gaze on the end of the walkway a far target. But target (i.e., visual fixation) distance has been shown to affect head and trunk motion during treadmill walking (Bloomberg, et al., 1992; Peters, et al., in review). Since the head and trunk can not maintain stable gaze without proper coordination with the lower body (Mulavara & Bloomberg, 2003), it would stand to reason that lower body kinematics may be altered as well when target distance is modified. The purpose of this study was to determine changes in toe vertical trajectory during treadmill walking due to changes in walking speed and target distance.

Acetylcholine contributes to the integration of self-movement cues in head direction cells.

PubMed

Yoder, Ryan M; Chan, Jeremy H M; Taube, Jeffrey S

2017-08-01

Acetylcholine contributes to accurate performance on some navigational tasks, but details of its contribution to the underlying brain signals are not fully understood. The medial septal area provides widespread cholinergic input to various brain regions, but selective damage to medial septal cholinergic neurons generally has little effect on landmark-based navigation, or the underlying neural representations of location and directional heading in visual environments. In contrast, the loss of medial septal cholinergic neurons disrupts navigation based on path integration, but no studies have tested whether these path integration deficits are associated with disrupted head direction (HD) cell activity. Therefore, we evaluated HD cell responses to visual cue rotations in a familiar arena, and during navigation between familiar and novel arenas, after muscarinic receptor blockade with systemic atropine. Atropine treatment reduced the peak firing rate of HD cells, but failed to significantly affect other HD cell firing properties. Atropine also failed to significantly disrupt the dominant landmark control of the HD signal, even though we used a procedure that challenged this landmark control. In contrast, atropine disrupted HD cell stability during navigation between familiar and novel arenas, where path integration normally maintains a consistent HD cell signal across arenas. These results suggest that acetylcholine contributes to path integration, in part, by facilitating the use of idiothetic cues to maintain a consistent representation of directional heading. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Characterization of the Q-switched MOBLAS Laser Transmitter and Its Ranging Performance Relative to a PTM Q-switched System

NASA Technical Reports Server (NTRS)

Degnan, J. J., III; Zagwodski, T. W.

1979-01-01

A prototype Q-switched Nd:YAG laser transmitter intended for use in the NASA mobile laser ranging system was subjected to various tests of temporal pulse shape and stability, output energy and stability, beam divergence, and range bias errors. Peak to peak variations in the mean range were as large as 30 cm and drift rates of system bias with time as large as 6 mm per minute of operation were observed. The incorporation of a fast electro-optic cavity dump into the oscillator gave significantly improved results. Reevaluation of the ranging performance after modification showed a reduction in the peak to peak variation in the mean range to the 2 or 3 cm level and a drift rate of system time biases of less than 1 mm per minute of operation. A qualitative physical explanation for the superior performance of cavity dumped lasers is given.

Variable threshold method for ECG R-peak detection.

PubMed

Kew, Hsein-Ping; Jeong, Do-Un

2011-10-01

In this paper, a wearable belt-type ECG electrode worn around the chest by measuring the real-time ECG is produced in order to minimize the inconvenient in wearing. ECG signal is detected using a potential instrument system. The measured ECG signal is transmits via an ultra low power consumption wireless data communications unit to personal computer using Zigbee-compatible wireless sensor node. ECG signals carry a lot of clinical information for a cardiologist especially the R-peak detection in ECG. R-peak detection generally uses the threshold value which is fixed. There will be errors in peak detection when the baseline changes due to motion artifacts and signal size changes. Preprocessing process which includes differentiation process and Hilbert transform is used as signal preprocessing algorithm. Thereafter, variable threshold method is used to detect the R-peak which is more accurate and efficient than fixed threshold value method. R-peak detection using MIT-BIH databases and Long Term Real-Time ECG is performed in this research in order to evaluate the performance analysis.

Effects of Variable Resistance Using Chains on Bench Throw Performance in Trained Rugby Players.

PubMed

Godwin, Mark S; Fernandes, John F T; Twist, Craig

2018-04-01

Godwin, MS, Fernandes, JFT, and Twist, C. Effects of variable resistance using chains on bench throw performance in trained rugby players. J Strength Cond Res 32(4): 950-954, 2018-This study sought to determine the effects of variable resistance using chain resistance on bench throw performance. Eight male rugby union players (19.4 ± 2.3 years, 88.8 ± 6.0 kg, 1RM 105.6 ± 17.0 kg) were recruited from a national league team. In a randomized crossover design, participant's performed 3 bench throws at 45% one repetition maximum (1RM) at a constant load (no chains) or a variable load (30% 1RM constant load and 15% 1RM variable load; chains) with 7 days between conditions. For each repetition, the peak and mean velocity, peak power, peak acceleration, and time to peak velocity were recorded. Differences in peak and mean power were very likely trivial and unclear between the chain and no chain conditions, respectively. Possibly greater peak and likely greater mean bar velocity were accompanied by likely to most likely greater bar velocity between 50 and 400 ms from initiation of bench press in the chain condition compared with the no chain condition. Accordingly, bar acceleration was very likely greater in the chain condition compared with the no chain condition. In conclusion, these results show that the inclusion of chain resistance can acutely enhance several variables in the bench press throw and gives support to this type of training.

Comparison of peak-picking workflows for untargeted liquid chromatography/high-resolution mass spectrometry metabolomics data analysis.

PubMed

Rafiei, Atefeh; Sleno, Lekha

2015-01-15

Data analysis is a key step in mass spectrometry based untargeted metabolomics, starting with the generation of generic peak lists from raw liquid chromatography/mass spectrometry (LC/MS) data. Due to the use of various algorithms by different workflows, the results of different peak-picking strategies often differ widely. Raw LC/HRMS data from two types of biological samples (bile and urine), as well as a standard mixture of 84 metabolites, were processed with four peak-picking softwares: Peakview®, Markerview™, MetabolitePilot™ and XCMS Online. The overlaps between the results of each peak-generating method were then investigated. To gauge the relevance of peak lists, a database search using the METLIN online database was performed to determine which features had accurate masses matching known metabolites as well as a secondary filtering based on MS/MS spectral matching. In this study, only a small proportion of all peaks (less than 10%) were common to all four software programs. Comparison of database searching results showed peaks found uniquely by one workflow have less chance of being found in the METLIN metabolomics database and are even less likely to be confirmed by MS/MS. It was shown that the performance of peak-generating workflows has a direct impact on untargeted metabolomics results. As it was demonstrated that the peaks found in more than one peak detection workflow have higher potential to be identified by accurate mass as well as MS/MS spectrum matching, it is suggested to use the overlap of different peak-picking workflows as preliminary peak lists for more rugged statistical analysis in global metabolomics investigations. Copyright © 2014 John Wiley & Sons, Ltd.

The Effects of Bicycle Frame Geometry on Muscle Activation and Power During a Wingate Anaerobic Test

PubMed Central

Ricard, Mark D.; Hills-Meyer, Patrick; Miller, Michael G.; Michael, Timothy J.

2006-01-01

The purpose of this study was to compare the effects of bicycle seat tube angles (STA) of (72° and 82°) on power production and EMG of the vastus laeralis (VL), vastus medialis (VM), semimembranous (SM), biceps femoris (BF) during a Wingate test (WAT). Twelve experienced cyclists performed a WAT at each STA. Repeated measures ANOVA was used to identify differences in muscular activation by STA. EMG variables were normalized to isometric maximum voluntary contraction (MVC). Paired t-tests were used to test the effects of STA on: peak power, average power, minimum power and percent power drop. Results indicated BF activation was significantly lower at STA 82° (482.9 ± 166.6 %MVC·s) compared to STA 72° (712.6 ± 265.6 %MVC·s). There were no differences in the power variables between STAs. The primary finding was that increasing the STA from 72° to 82° enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Key Points Road cyclists claim that bicycle seat tube angles between 72° and 76° are most effective for optimal performance in racing. Triathletes typically use seat tube angles greater than 76°. It is thought that a seat tube angle greater than 76° facilitates a smoother bike to run transition in the triathlon. Increasing the seat tube angle from 72 to 82 enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Reduced hamstring muscular activation in the triathlon frame (82 seat tube angle) may serve to reduce hamstring tightness following the bike phase of the triathlon, allowing the runner to use a longer stride length. PMID:24198678

Electrical Stimulation of the Ventral Tegmental Area Induces Reanimation from General Anesthesia

PubMed Central

Solt, Ken; Van Dort, Christa J.; Chemali, Jessica J.; Taylor, Norman E.; Kenny, Jonathan D.; Brown, Emery N.

2014-01-01

BACKGROUND Methylphenidate or a D1 dopamine receptor agonist induce reanimation (active emergence) from general anesthesia. We tested whether electrical stimulation of dopaminergic nuclei also induces reanimation from general anesthesia. METHODS In adult rats, a bipolar insulated stainless steel electrode was placed in the ventral tegmental area (VTA, n = 5) or substantia nigra (SN, n = 5). After a minimum 7-day recovery period, the isoflurane dose sufficient to maintain loss of righting was established. Electrical stimulation was initiated and increased in intensity every 3 min to a maximum of 120μA. If stimulation restored the righting reflex, an additional experiment was performed at least 3 days later during continuous propofol anesthesia. Histological analysis was conducted to identify the location of the electrode tip. In separate experiments, stimulation was performed in the prone position during general anesthesia with isoflurane or propofol, and the electroencephalogram was recorded. RESULTS To maintain loss of righting, the dose of isoflurane was 0.9% ± 0.1 vol%, and the target plasma dose of propofol was 4.4 μg/ml ± 1.1 μg/ml (mean ± SD). In all rats with VTA electrodes, electrical stimulation induced a graded arousal response including righting that increased with current intensity. VTA stimulation induced a shift in electroencephalogram peak power from δ (<4 Hz) to θ (4–8 Hz). In all rats with SN electrodes, stimulation did not elicit an arousal response or significant electroencephalogram changes. CONCLUSIONS Electrical stimulation of the VTA, but not the SN, induces reanimation during general anesthesia with isoflurane or propofol. These results are consistent with the hypothesis that dopamine release by VTA, but not SN, neurons induces reanimation from general anesthesia. PMID:24398816

Impact of Wet-Weather Peak Flow Blending on Disinfection Performance

EPA Science Inventory

A U.S. EPA study evaluated the impact on disinfection during peak flows (wet-weather flow events) when a portion of the flow to the wastewater treatment plant (WWTP) bypasses secondary treatment prior to disinfection. The practice of bypassing secondary treatment during peak flow...

Comparison of High-Intensity Interval Training and Moderate-to-Vigorous Continuous Training for Cardiometabolic Health and Exercise Enjoyment in Obese Young Women: A Randomized Controlled Trial.

PubMed

Kong, Zhaowei; Fan, Xitao; Sun, Shengyan; Song, Lili; Shi, Qingde; Nie, Jinlei

2016-01-01

The aim of this study was to compare the effects of 5-week high-intensity interval training (HIIT) and moderate-to-vigorous intensity continuous training (MVCT) on cardiometabolic health outcomes and enjoyment of exercise in obese young women. A randomized controlled experiment was conducted that involved thirty-one obese females (age range of 18-30) randomly assigned to either HIIT or MVCT five-week training programs. Participants in HIIT condition performed 20 min of repeated 8 s cycling interspersed with 12 s rest intervals, and those in MVCT condition cycled continuously for 40 min at 60-80% of peak oxygen consumption ([Formula: see text]O2peak), both for four days in a week. Outcomes such as [Formula: see text]O2peak, body composition estimated by bioimpedance analysis, blood lipids, and serum sexual hormones were measured at pre-and post-training. The scores of Physical Activity Enjoyment Scale (PAES) were collected during the intervention. After training, [Formula: see text]O2peak increased significantly for both training programs (9.1% in HIIT and 10.3% in MVCT) (p = 0.010, η2 = 0.41). Although MVCT group had a significant reduction in total body weight (TBW, -1.8%, p = 0.034), fat mass (FM, - 4.7%, p = 0.002) and percentage body fat (PBF, -2.9%, p = 0.016), there were no significant between-group differences in the change of the pre- and post-measures of these variables. The HIIT group had a higher score on PAES than the MVCT group during the intervention. For both conditions, exercise training led to a decline in resting testosterone and estradiol levels, but had no significant effect on blood lipids. Both HIIT and MVCT are effective in improving cardiorespiratory fitness and in reducing sexual hormones in obese young women; however, HIIT is a more enjoyable and time-efficient strategy. The mild-HIIT protocol seems to be useful for at least maintaining the body weight among sedentary individuals.

Comparison of High-Intensity Interval Training and Moderate-to-Vigorous Continuous Training for Cardiometabolic Health and Exercise Enjoyment in Obese Young Women: A Randomized Controlled Trial

PubMed Central

Sun, Shengyan; Song, Lili; Shi, Qingde

2016-01-01

Objective The aim of this study was to compare the effects of 5-week high-intensity interval training (HIIT) and moderate-to-vigorous intensity continuous training (MVCT) on cardiometabolic health outcomes and enjoyment of exercise in obese young women. Methods A randomized controlled experiment was conducted that involved thirty-one obese females (age range of 18–30) randomly assigned to either HIIT or MVCT five-week training programs. Participants in HIIT condition performed 20 min of repeated 8 s cycling interspersed with 12 s rest intervals, and those in MVCT condition cycled continuously for 40 min at 60–80% of peak oxygen consumption (V˙O2peak), both for four days in a week. Outcomes such as V˙O2peak, body composition estimated by bioimpedance analysis, blood lipids, and serum sexual hormones were measured at pre-and post-training. The scores of Physical Activity Enjoyment Scale (PAES) were collected during the intervention. Results After training, V˙O2peak increased significantly for both training programs (9.1% in HIIT and 10.3% in MVCT) (p = 0.010, η2 = 0.41). Although MVCT group had a significant reduction in total body weight (TBW, −1.8%, p = 0.034), fat mass (FM, - 4.7%, p = 0.002) and percentage body fat (PBF, −2.9%, p = 0.016), there were no significant between-group differences in the change of the pre- and post-measures of these variables. The HIIT group had a higher score on PAES than the MVCT group during the intervention. For both conditions, exercise training led to a decline in resting testosterone and estradiol levels, but had no significant effect on blood lipids. Conclusion Both HIIT and MVCT are effective in improving cardiorespiratory fitness and in reducing sexual hormones in obese young women; however, HIIT is a more enjoyable and time-efficient strategy. The mild-HIIT protocol seems to be useful for at least maintaining the body weight among sedentary individuals. PMID:27368057

Sildenafil does not improve steady state cardiovascular hemodynamics, peak power, or 15-km time trial cycling performance at simulated moderate or high altitudes in men and women.

PubMed

Kressler, Jochen; Stoutenberg, Mark; Roos, Bernard A; Friedlander, Anne L; Perry, Arlette C; Signorile, Joseph F; Jacobs, Kevin A

2011-12-01

Sildenafil improves oxygen delivery and maximal exercise capacity at very high altitudes (≥ 4,350 m), but it is unknown whether sildenafil improves these variables and longer-duration exercise performance at moderate and high altitudes where competitions are more common. The purpose of this study was to determine the effects of sildenafil on cardiovascular hemodynamics, arterial oxygen saturation (SaO(2)), peak exercise capacity (W (peak)), and 15-km time trial performance in endurance-trained subjects at simulated moderate (MA; ~2,100 m, 16.2% F(I)O(2)) and high (HA; ~3,900 m, 12.8% F(I)O(2)) altitudes. Eleven men and ten women completed two HA W (peak) trials after ingesting placebo or 50 mg sildenafil. Subjects then completed four exercise trials (30 min at 55% of altitude-specific W (peak) + 15-km time trial) at MA and HA after ingesting placebo or 50 mg sildenafil. All trials were performed in randomized, counterbalanced, and double-blind fashion. Sildenafil had little influence on cardiovascular hemodynamics at MA or HA, but did result in higher SaO(2) values (+3%, p < 0.05) compared to placebo during steady state and time trial exercise at HA. W (peak) at HA was 19% lower than SL (p < 0.001) and was not significantly affected by sildenafil. Similarly, the significantly slower time trial performance at MA (28.1 ± 0.5 min, p = 0.016) and HA (30.3 ± 0.6 min, p < 0.001) compared to SL (27.5 ± 0.6 min) was unaffected by sildenafil. We conclude that sildenafil is unlikely to exert beneficial effects at altitudes <4,000 m for a majority of the population.

Relative net vertical impulse determines jumping performance.

PubMed

Kirby, Tyler J; McBride, Jeffrey M; Haines, Tracie L; Dayne, Andrea M

2011-08-01

The purpose of this investigation was to determine the relationship between relative net vertical impulse and jump height in a countermovement jump and static jump performed to varying squat depths. Ten college-aged males with 2 years of jumping experience participated in this investigation (age: 23.3 ± 1.5 years; height: 176.7 ± 4.5 cm; body mass: 84.4 ± 10.1 kg). Subjects performed a series of static jumps and countermovement jumps in a randomized fashion to a depth of 0.15, 0.30, 0.45, 0.60, and 0.75 m and a self-selected depth (static jump depth = 0.38 ± 0.08 m, countermovement jump depth = 0.49 ± 0.06 m). During the concentric phase of each jump, peak force, peak velocity, peak power, jump height, and net vertical impulse were recorded and analyzed. Net vertical impulse was divided by body mass to produce relative net vertical impulse. Increasing squat depth corresponded to a decrease in peak force and an increase in jump height and relative net vertical impulse for both static jump and countermovement jump. Across all depths, relative net vertical impulse was statistically significantly correlated to jump height in the static jump (r = .9337, p < .0001, power = 1.000) and countermovement jump (r = .925, p < .0001, power = 1.000). Across all depths, peak force was negatively correlated to jump height in the static jump (r = -0.3947, p = .0018, power = 0.8831) and countermovement jump (r = -0.4080, p = .0012, power = 0.9050). These results indicate that relative net vertical impulse can be used to assess vertical jump performance, regardless of initial squat depth, and that peak force may not be the best measure to assess vertical jump performance.

Shuttle Ku-band and S-band communications implementation study

NASA Technical Reports Server (NTRS)

Dodds, J. G.; Huth, G. K.; Nilsen, P. W.; Polydoros, A.; Simon, M. K.; Weber, C. L.

1980-01-01

Various aspects of the shuttle orbiter S-band network communication system, the S-band payload communication system, and the Ku-band communication system are considered. A method is proposed for obtaining more accurate S-band antenna patterns of the actual shuttle orbiter vehicle during flight because the preliminary antenna patterns using mock-ups are not realistic that they do not include the effects of additional appendages such as wings and tail structures. The Ku-band communication system is discussed especially the TDRS antenna pointing accuracy with respect to the orbiter and the modifications required and resulting performance characteristics of the convolutionally encoded high data rate return link to maintain bit synchronizer lock on the ground. The TDRS user constraints on data bit clock jitter and data asymmetry on unbalanced QPSK with noisy phase references are included. The S-band payload communication system study is outlined including the advantages and experimental results of a peak regulator design built and evaluated by Axiomatrix for the bent-pipe link versus the existing RMS-type regulator. The nominal sweep rate for the deep-space transponder of 250 Hz/s, and effects of phase noise on the performance of a communication system are analyzed.

Accumulation of Inertial Sensory Information in the Perception of Whole Body Yaw Rotation.

PubMed

Nesti, Alessandro; de Winkel, Ksander; Bülthoff, Heinrich H

2017-01-01

While moving through the environment, our central nervous system accumulates sensory information over time to provide an estimate of our self-motion, allowing for completing crucial tasks such as maintaining balance. However, little is known on how the duration of the motion stimuli influences our performances in a self-motion discrimination task. Here we study the human ability to discriminate intensities of sinusoidal (0.5 Hz) self-rotations around the vertical axis (yaw) for four different stimulus durations (1, 2, 3 and 5 s) in darkness. In a typical trial, participants experienced two consecutive rotations of equal duration and different peak amplitude, and reported the one perceived as stronger. For each stimulus duration, we determined the smallest detectable change in stimulus intensity (differential threshold) for a reference velocity of 15 deg/s. Results indicate that differential thresholds decrease with stimulus duration and asymptotically converge to a constant, positive value. This suggests that the central nervous system accumulates sensory information on self-motion over time, resulting in improved discrimination performances. Observed trends in differential thresholds are consistent with predictions based on a drift diffusion model with leaky integration of sensory evidence.

Evaluation of human serum of severe rheumatoid arthritis by confocal Raman spectroscopy

NASA Astrophysics Data System (ADS)

Carvalho, C. S.; Raniero, L.; Santo, A. M. E.; Pinheiro, M. M.; Andrade, L. E. C.; Cardoso, M. A. G.; Junior, J. S.; Martin, A. A.

2010-02-01

Rheumatoid Arthritis is a systemic chronic inflammatory disease, recurrent and systemic, initiated by autoantibodies and maintained by inflammatory mechanisms cellular applicants. The evaluation of this disease to promote early diagnosis, need an associations of many tools, such as clinical, physical examination and thorough medical history. However, there is no satisfactory consensus due to its complexity. In the present work, confocal Raman spectroscopy was used to evaluate the biochemical composition of human serum of 40 volunteers, 24 patients with rheumatoid arthritis presenting clinical signs and symptoms, and 16 healthy donors. The technique of latex agglutination for the polystyrene covered with human immunoglobulin G and PCR (protein c-reactive) was performed for confirmation of possible false-negative results within the groups, facilitating the statistical interpretation and validation of the technique. This study aimed to verify the changes for the characteristics Raman peaks of biomolecules such as immunoglobulins amides and protein. The results were highly significant with a good separation between groups mentioned. The discriminant analysis was performed through the principal components and correctly identified 92% of the donors. Based on these results, we observed the behavior of arthritis autoimmune, evident in certain spectral regions that characterize the serological differences between the groups.

Field Tolerances for the Triplet Quadrupoles of the LHC High Luminosity Lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nosochkov, Yuri; Cai, Y.; Jiao, Y.

2012-06-25

It has been proposed to implement the so-called Achromatic Telescopic Squeezing (ATS) scheme in the LHC high luminosity (HL) lattice to reduce beta functions at the Interaction Points (IP) up to a factor of 8. As a result, the nominal 4.5 km peak beta functions reached in the Inner Triplets (IT) at collision will be increased by the same factor. This, therefore, justifies the installation of new, larger aperture, superconducting IT quadrupoles. The higher beta functions will enhance the effects of the triplet quadrupole field errors leading to smaller beam dynamic aperture (DA). To maintain the acceptable DA, the effectsmore » of the triplet field errors must be re-evaluated, thus specifying new tolerances. Such a study has been performed for the so-called '4444' collision option of the HL-LHC layout version SLHCV3.01, where the IP beta functions are reduced by a factor of 4 in both planes with respect to a pre-squeezed value of 60 cm at two collision points. The dynamic aperture calculations were performed using SixTrack. The impact on the triplet field quality is presented.« less

Characterizing cardiac dysfunction in fetuses with left congenital diaphragmatic hernia.

PubMed

Cruz-Lemini, Mónica; Valenzuela-Alcaraz, Brenda; Granados-Montiel, Julio; Martínez, Josep M; Crispi, Fátima; Gratacós, Eduard; Cruz-Martínez, Rogelio

2018-03-23

To evaluate cardiac function by conventional echocardiography and tissue Doppler imaging in fetuses with left congenital diaphragmatic hernia (CDH). Conventional echocardiography (myocardial performance index, ventricular filling velocities, and E/A ratios) and tissue Doppler imaging (annular myocardial peak velocities, E/E' and E'/A' ratios) in mitral, septal, and tricuspid annulus were evaluated in a cohort of 31 left-sided CDH fetuses and compared with 75 controls matched for gestational age 2:1. In comparison to controls, CDH fetuses had prolonged isovolumetric time periods (isovolumetric contraction time 35 ms vs 28 ms, P < .001), with higher myocardial performance index (0.49 vs 0.42, P < .001) and tricuspid E/A ratios (0.77 vs 0.72, P = .033). Longitudinal function assessed by tissue Doppler showed signs of impaired relaxation (mitral lateral A' 8.0 vs 10.1 cm/s, P < .001 and an increased mitral lateral E'/A' ratio 0.93 vs 0.78, P < .001) in the CDH fetuses as compared with controls, with preserved systolic function. Left CDH fetuses show echocardiographic signs of diastolic dysfunction, probably secondary to fetal heart compression, maintaining a preserved systolic function. © 2018 John Wiley & Sons, Ltd.

Systems and Methods for Peak-Seeking Control

NASA Technical Reports Server (NTRS)

Ryan, John J (Inventor); Speyer, Jason L (Inventor)

2013-01-01

A computerized system and method for peak-seeking-control that uses a unique Kalman filter design to optimize a control loop, in real time, to either maximize or minimize a performance function of a physical object ("plant"). The system and method achieves more accurate and efficient peak-seeking-control by using a time-varying Kalman filter to estimate both the performance function gradient (slope) and Hessian (curvature) based on direct position measurements of the plant, and does not rely upon modeling the plant response to persistent excitation. The system and method can be naturally applied in various applications in which plant performance functions have multiple independent parameters, and it does not depend upon frequency separation to distinguish between system dimensions.

Reduction in obesity and coronary risk factors after high caloric exercise training in overweight coronary patients.

PubMed

Savage, Patrick D; Brochu, Martin; Poehlman, Eric T; Ades, Philip A

2003-08-01

The majority of patients with coronary heart disease (CHD) are overweight. However, little weight loss occurs with participation in a standard cardiac rehabilitation (CR) program. Fifteen overweight patients (average body mass index of 31.0 kg/m2) with CHD completed a 4-month exercise training program in a CR program. The exercise program consisted primarily of walking long duration (60-90 minutes per session) 5 to 7 days per week at a relatively low intensity of 50% to 60% of peak VO2. Measures of body composition by dual-energy x-ray absorptiometry, body fat distribution by computed tomography, plasma lipid-lipoprotein, glucose and insulin concentrations, and peak VO2 were obtained before and after the exercise intervention. Patients maintained an isocaloric diet throughout the study. Patients had reductions in total body weight (-4.6 kg), fat mass (-3.6 kg), percent body fat (-2.9%), and waist circumference (-5.6 cm) (all P <.001) while maintaining fat-free mass. Subcutaneous adipose tissue was reduced by 12% (P <.001) and visceral adipose tissue was lowered by 14% (P <.001). There were favorable changes in the lipid-metabolic profile with reductions in triglyceride levels (-23.7%), total cholesterol/HDL-C ratio (-14.3%), and fasting insulin levels (-22.3%) (all P <.05). Peak VO2 increased by 21.2% (P <.001). The present pilot study results suggest that a high caloric training exercise training program in the CR setting may be effective in promoting weight loss and improving coronary risk factors in overweight coronary patients. Although additional research with randomized control patients is needed, this alternative to traditional CR may be considered to maximize weight loss as part of a secondary prevention program.

Intraglomerular inhibition maintains mitral cell response contrast across input frequencies

PubMed Central

Shao, Zuoyi; Puche, Adam C.

2013-01-01

Odor signals are transmitted to the olfactory bulb by olfactory nerve (ON) synapses onto mitral/tufted cells (MTCs) and external tufted cells (ETCs); ETCs provide additional feed-forward excitation to MTCs. Both are strongly regulated by intraglomerular inhibition that can last up to 1 s and, when blocked, dramatically increases ON-evoked MC spiking. Intraglomerular inhibition thus limits the magnitude and duration of MC spike responses to sensory input. In vivo, sensory input is repetitive, dictated by sniffing rates from 1 to 8 Hz, potentially summing intraglomerular inhibition. To investigate this, we recorded MTC responses to 1- to 8-Hz ON stimulation in slices. Inhibitory postsynaptic current area (charge) following each ON stimulation was unchanged from 1 to 5 Hz and modestly paired-pulse attenuated at 8 Hz, suggesting there is no summation and only limited decrement at the highest input frequencies. Next, we investigated frequency independence of intraglomerular inhibition on MC spiking. MCs respond to single ON shocks with an initial spike burst followed by reduced spiking decaying to baseline. Upon repetitive ON stimulation peak spiking is identical across input frequencies but the ratio of peak-to-minimum rate before the stimulus (max-min) diminishes from 30:1 at 1 Hz to 15:1 at 8 Hz. When intraglomerular inhibition is selectively blocked, peak spike rate is unchanged but trough spiking increases markedly decreasing max-min firing ratios from 30:1 at 1 Hz to 2:1 at 8 Hz. Together, these results suggest intraglomerular inhibition is relatively frequency independent and can “sharpen” MC responses to input across the range of frequencies. This suggests that glomerular circuits can maintain “contrast” in MC encoding during sniff-sampled inputs. PMID:23926045

Intraglomerular inhibition maintains mitral cell response contrast across input frequencies.

PubMed

Shao, Zuoyi; Puche, Adam C; Shipley, Michael T

2013-11-01

Odor signals are transmitted to the olfactory bulb by olfactory nerve (ON) synapses onto mitral/tufted cells (MTCs) and external tufted cells (ETCs); ETCs provide additional feed-forward excitation to MTCs. Both are strongly regulated by intraglomerular inhibition that can last up to 1 s and, when blocked, dramatically increases ON-evoked MC spiking. Intraglomerular inhibition thus limits the magnitude and duration of MC spike responses to sensory input. In vivo, sensory input is repetitive, dictated by sniffing rates from 1 to 8 Hz, potentially summing intraglomerular inhibition. To investigate this, we recorded MTC responses to 1- to 8-Hz ON stimulation in slices. Inhibitory postsynaptic current area (charge) following each ON stimulation was unchanged from 1 to 5 Hz and modestly paired-pulse attenuated at 8 Hz, suggesting there is no summation and only limited decrement at the highest input frequencies. Next, we investigated frequency independence of intraglomerular inhibition on MC spiking. MCs respond to single ON shocks with an initial spike burst followed by reduced spiking decaying to baseline. Upon repetitive ON stimulation peak spiking is identical across input frequencies but the ratio of peak-to-minimum rate before the stimulus (max-min) diminishes from 30:1 at 1 Hz to 15:1 at 8 Hz. When intraglomerular inhibition is selectively blocked, peak spike rate is unchanged but trough spiking increases markedly decreasing max-min firing ratios from 30:1 at 1 Hz to 2:1 at 8 Hz. Together, these results suggest intraglomerular inhibition is relatively frequency independent and can "sharpen" MC responses to input across the range of frequencies. This suggests that glomerular circuits can maintain "contrast" in MC encoding during sniff-sampled inputs.

Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump.

PubMed

Yun, Sung Joon; Kim, Moon-Hwan; Weon, Jong-Hyuck; Kim, Young; Jung, Sung-Hoon; Kwon, Oh-Yun

2016-08-01

[Purpose] This study assessed the relationships between peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height. [Subjects and Methods] Eighteen healthy volunteers participated in the study. Each participant completed tests for peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height. [Results] The results showed (1) a moderate correlation between ankle dorsiflexion range of motion and countermovement jump height and (2) a high correlation between peak first toe flexor muscle strength and countermovement jump height. Peak first toe flexor muscle strength and ankle dorsiflexion range of motion are the main contributors to countermovement jump performance. [Conclusion] These findings indicate that the measurement of peak first toe flexor muscle strength and ankle dorsiflexion range of motion may be useful in clinical practice for improving jump performance in athletes training for sports such as volleyball and basketball.

A Database for Comparative Electrochemical Performance of Commercial 18650-Format Lithium-Ion Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barkholtz, Heather M.; Fresquez, Armando; Chalamala, Babu R.

Lithium-ion batteries are a central technology to our daily lives with widespread use in mobile devices and electric vehicles. These batteries are also beginning to be widely used in electric grid infrastructure support applications which have stringent safety and reliability requirements. Typically, electrochemical performance data is not available for modelers to validate their simulations, mechanisms, and algorithms for lithium-ion battery performance and lifetime. In this paper, we report on the electrochemical performance of commercial 18650 cells at a variety of temperatures and discharge currents. We found that LiFePO 4 is temperature tolerant for discharge currents at or below 10 Amore » whereas LiCoO 2, LiNi xCo yAl 1-x-yO 2, and LiNi 0.80Mn 0.15Co 0.05O 2 exhibited optimal electrochemical performance when the temperature is maintained at 15°C. LiNi xCo yAl 1-x-yO 2 showed signs of lithium plating at lower temperatures, evidenced by irreversible capacity loss and emergence of a high-voltage differential capacity peak. Furthermore, all cells need to be monitored for self-heating, as environment temperature and high discharge currents may elicit an unintended abuse condition. Overall, this study shows that lithium-ion batteries are highly application-specific and electrochemical behavior must be well understood for safe and reliable operation. Additionally, data collected in this study is available for anyone to download for further analysis and model validation.« less

A Database for Comparative Electrochemical Performance of Commercial 18650-Format Lithium-Ion Cells

DOE PAGES

Barkholtz, Heather M.; Fresquez, Armando; Chalamala, Babu R.; ...

2017-09-08

Lithium-ion batteries are a central technology to our daily lives with widespread use in mobile devices and electric vehicles. These batteries are also beginning to be widely used in electric grid infrastructure support applications which have stringent safety and reliability requirements. Typically, electrochemical performance data is not available for modelers to validate their simulations, mechanisms, and algorithms for lithium-ion battery performance and lifetime. In this paper, we report on the electrochemical performance of commercial 18650 cells at a variety of temperatures and discharge currents. We found that LiFePO 4 is temperature tolerant for discharge currents at or below 10 Amore » whereas LiCoO 2, LiNi xCo yAl 1-x-yO 2, and LiNi 0.80Mn 0.15Co 0.05O 2 exhibited optimal electrochemical performance when the temperature is maintained at 15°C. LiNi xCo yAl 1-x-yO 2 showed signs of lithium plating at lower temperatures, evidenced by irreversible capacity loss and emergence of a high-voltage differential capacity peak. Furthermore, all cells need to be monitored for self-heating, as environment temperature and high discharge currents may elicit an unintended abuse condition. Overall, this study shows that lithium-ion batteries are highly application-specific and electrochemical behavior must be well understood for safe and reliable operation. Additionally, data collected in this study is available for anyone to download for further analysis and model validation.« less

Effects of multiple polyaniline layers immobilized on carbon nanotube and glutaraldehyde on performance and stability of biofuel cell

NASA Astrophysics Data System (ADS)

Christwardana, Marcelinus; Kwon, Yongchai

2015-12-01

Enzymatic biofuel cell (EBC) employing new catalyst for anode electrode is fabricated. The new catalyst consists of glucose oxidase (GOx), polyaniline (PANI) and carbon nanotube (CNT) that are multiply stacked together and finally the stack layer is surrounded by glutaraldehyde (GA) (GA/[GOx/PANI/CNT]n). To evaluate how the GA/[GOx/PANI/CNT]n layer affects EBC performance and stability, electrochemical characterizations are implemented. Regarding optimization, GA/[GOx/PANI/CNT]3 is determined. For elucidating reaction mechanism between glucose and flavin adenine dinucleotide (FAD) of GA/[GOx/PANI/CNT]3, associated investigations are performed. In the evaluations, drop in reduction current peak of FAD is observed with provisions of glucose and O2, while glucose does not influence FAD reaction without O2, confirming O2 makes mediator role. When the GA/[GOx/PANI/CNT]3 layer is adopted, superior catalytic activity and EBC performance are gained (electron transfer rate constant of 5.1 s-1, glucose sensitivity of 150 ìA mM-1 cm-2, and EBC maximum power density (MPD) of 0.29 mW cm-2). Regarding EBC stability, MPD of EBC adopting GA/[GOx/PANI/CNT]3 maintains up to 93% of their initial value even after four weeks. Although GA is little effective for improving EBC performance, EBC stability is helped by GA due to its adhesion promotion capability with [GOx/PANI/CNT]n layer.

Effects of Differing Response-Force Requirements on Food-Maintained Responding in C57BL/6J Mice

ERIC Educational Resources Information Center

Zarcone, Troy J.; Chen, Rong; Fowler, Stephen C.

2009-01-01

The effect of force requirements on response effort was examined using inbred C57BL/6J mice trained to press a disk with their snout. Lateral peak forces greater than 2 g were defined as responses (i.e., all responses above the measurement threshold). Different, higher force requirements were used to define criterion responses (a subclass of all…

Effect of varying heart rate on intra-ventricular filling fluid dynamics

NASA Astrophysics Data System (ADS)

Santhanakrishnan, Arvind; Okafor, Ikechukwu; Angirish, Yagna; Yoganathan, Ajit

2013-11-01

Impaired exercise tolerance is used to delineate asymptomatic patients during the clinical diagnosis of diastolic left heart failure. Examining the effects of varying heart rate on intra-ventricular filling can provide a physical understanding of the specific flow characteristics that are impacted during exercise. In this study, diastolic filling was investigated with an anatomical left ventricle (LV) physical model under normal heart rate of 70 bpm, and varying exercise conditions of 100 bpm and 120 bpm. The LV model was incorporated into a flow loop and tuned for physiological inflow rates and outflow pressures. 2D PIV measurements were conducted along 3 parallel longitudinal planes. The systemic pressure was maintained the same across all test conditions. The E/A ratio was maintained within 1.0-1.2 across all heart rates. The strength of the mitral vortex ring formed during E-wave, as well as the peak incoming jet velocity, decreased with increasing heart rate. During peak flow of the A-wave, the vortex ring propagated farther into the LV for 120 bpm as compared to 70 bpm. The results point to the heightened role of the atrial kick for optimal LV filling during exercise conditions. This study was funded by a grant from the National Heart, Lung and Blood Institute (RO1HL70262).

Aiding the Detection of QRS Complex in ECG Signals by Detecting S Peaks Independently.

PubMed

Sabherwal, Pooja; Singh, Latika; Agrawal, Monika

2018-03-30

In this paper, a novel algorithm for the accurate detection of QRS complex by combining the independent detection of R and S peaks, using fusion algorithm is proposed. R peak detection has been extensively studied and is being used to detect the QRS complex. Whereas, S peaks, which is also part of QRS complex can be independently detected to aid the detection of QRS complex. In this paper, we suggest a method to first estimate S peak from raw ECG signal and then use them to aid the detection of QRS complex. The amplitude of S peak in ECG signal is relatively weak than corresponding R peak, which is traditionally used for the detection of QRS complex, therefore, an appropriate digital filter is designed to enhance the S peaks. These enhanced S peaks are then detected by adaptive thresholding. The algorithm is validated on all the signals of MIT-BIH arrhythmia database and noise stress database taken from physionet.org. The algorithm performs reasonably well even for the signals highly corrupted by noise. The algorithm performance is confirmed by sensitivity and positive predictivity of 99.99% and the detection accuracy of 99.98% for QRS complex detection. The number of false positives and false negatives resulted while analysis has been drastically reduced to 80 and 42 against the 98 and 84 the best results reported so far.

A comparison of the shuttle and 6 minute walking tests with measured peak oxygen consumption in patients with heart failure.

PubMed

Green, D J; Watts, K; Rankin, S; Wong, P; O'Driscoll, J G

2001-09-01

This study investigated the use of an incremental, externally-paced 10 m shuttle walk test (SWT) as an objective, reliable and predictive test of functional capacity in patients with heart failure (CHF). The SWT was compared to a 6 minute walk test (6WT) and a maximal symptom-limited treadmill peak oxygen consumption (VO2peak) test. Experiment 1 examined the reproducibility of the SWT. Two SWF trials were performed and distance ambulated (DA), heart rate (HR) and rate of perceived exertion (RPE) results compared. In experiment 2, SWT, 6WT, and VO2 peak tests were performed and HR. RPE and ambulatory VO2 compared. The SWT demonstrated strong test/retest reliability for DA (r = 0.98). HR (r = 0.96) and RPE (r = 0.89). Treadmill VO2 peak was significantly correlated with DA during the SWT (r = 0.83, P < 0.05), but not the 6WT. SWT peak VO2 (18.5 +/- 1.8 ml.kg(-1) x min(-1)) and treadmill VO2 peak (18.3 +/-2.0 ml.kg(-1) x min(-1)) were also highly correlated (r = 0.78, P < 0.05). Conversely, 6WT peak VO2 and treadmill VO2 peak were not significantly correlated. This study suggests the SWT is a reliable, objective test, highly predictive of VO2 peak which may be a more optimal field exercise test than the self paced 6WT.

The short physical performance battery as a predictor of functional capacity after stroke.

PubMed

Stookey, Alyssa D; Katzel, Leslie I; Steinbrenner, Gregory; Shaughnessy, Marianne; Ivey, Frederick M

2014-01-01

The short physical performance battery is a widely used instrument for quantifying lower extremity function in older adults. However, its utility for predicting endurance-based measures of functional performance that are more difficult to conduct in clinical settings is unknown. An understanding of this could be particularly relevant in mobility impaired stroke survivors, for whom establishing the predictive strength of simpler to perform measures would aid in tracking broader categories of functional disability. This cross-sectional study was conducted to determine whether the short physical performance battery is related to functional measures with a strong endurance component. Functional measures (short physical performance battery, peak aerobic capacity, and 6-minute walk) were obtained and compared for the first time in stroke survivors with hemiparetic gait. Pearson correlation coefficients were used to assess strength of the relationships (α P < .05). Forty-three stroke participants performed a standardized short physical performance battery. Forty-one of the subjects completed a 6-minute walk, and 40 completed a peak treadmill test. Mean short physical performance battery (6.3 ± 2.5 [mean ± SD]), 6-minute walk (242 ± 115 meters), and peak aerobic capacity (17.4 ± 5.4 mL/kg/min) indicated subjects had moderate to severely impaired lower extremity functional performance. The short physical performance battery was related to both 6-minute walk (r = 0.76; P < .0001) and peak fitness (r = 0.52; P < .001). Our results show that the short physical performance battery may be reflective of endurance-based, longer-distance performance measures that would be difficult to perform in standard clinical stroke settings. Additional studies are needed to explore the value of using the short physical performance battery to assess rehabilitation-related functional progression after stroke. Published by Elsevier Inc.

Approaches to characterise chromatographic column performance based on global parameters accounting for peak broadening and skewness.

PubMed

Baeza-Baeza, J J; Pous-Torres, S; Torres-Lapasió, J R; García-Alvarez-Coque, M C

2010-04-02

Peak broadening and skewness are fundamental parameters in chromatography, since they affect the resolution capability of a chromatographic column. A common practice to characterise chromatographic columns is to estimate the efficiency and asymmetry factor for the peaks of one or more solutes eluted at selected experimental conditions. This has the drawback that the extra-column contributions to the peak variance and skewness make the peak shape parameters depend on the retention time. We propose and discuss here the use of several approaches that allow the estimation of global parameters (non-dependent on the retention time) to describe the column performance. The global parameters arise from different linear relationships that can be established between the peak variance, standard deviation, or half-widths with the retention time. Some of them describe exclusively the column contribution to the peak broadening, whereas others consider the extra-column effects also. The estimation of peak skewness was also possible for the approaches based on the half-widths. The proposed approaches were applied to the characterisation of different columns (Spherisorb, Zorbax SB, Zorbax Eclipse, Kromasil, Chromolith, X-Terra and Inertsil), using the chromatographic data obtained for several diuretics and basic drugs (beta-blockers). Copyright (c) 2010 Elsevier B.V. All rights reserved.

Determination of triterpenic acids in fruits by a novel high performance liquid chromatography method with high sensitivity and specificity.

PubMed

Zhang, Shijuan; Sun, Yuanpeng; Sun, Zhiwei; Wang, Xiaoyan; You, Jinmao; Suo, Yourui

2014-03-01

A novel and interesting pre-column derivatisation method was developed for the analysis of triterpenic acids by high-performance liquid chromatography (HPLC) with fluorescence detection. Each triterpenic acid produced two HPLC peaks with similar peak areas after derivatising with chiral 1-(9H-carbazol-9-yl) propan-2-yl-methanesulfonate (CPMS), while the fatty acid derivative of CPMS had only one peak. This phenomenon greatly increased the confidence in analyte confirmation. Compound with only one peak or two peaks differing greatly in their peak areas could be excluded from the target compound list. CPMS was compared with five other derivatising reagents, four of which produced only one peak for one triterpenic acid, to study the possible mechanism. Analytes with different behaviours were also studied to better interpret the mechanism. The proposed method also showed the merits of high sensitivity and less sample consumption. It was successfully applied to the analysis of triterpenic acids in fruit peels and flesh. There is no prior report on the two peak phenomenon of triterpenic acids. The information provided in this study will be helpful for those who are also engaged in derivatisation study. Copyright © 2013 Elsevier Ltd. All rights reserved.

Feasibility of the Precise Energy Calibration for Fast Neutron Spectrometers

NASA Astrophysics Data System (ADS)

Gaganov, V. V.; Usenko, P. L.; Kryzhanovskaja, M. A.

2017-12-01

Computational studies aimed at improving the accuracy of measurements performed using neutron generators with a tritium target were performed. A measurement design yielding an extremely narrow peak in the energy spectrum of DT neutrons was found. The presence of such a peak establishes the conditions for precise energy calibration of fast-neutron spectrometers.

Sensory organization for balance: specific deficits in Alzheimer's but not in Parkinson's disease.

PubMed

Chong, R K; Horak, F B; Frank, J; Kaye, J

1999-03-01

The cause of frequent falling in patients with dementia of the Alzheimer type (AD) is not well understood. Distraction from incongruent visual stimuli may be an important factor as suggested by their poor performance in tests of shifting visual attention in other studies. The purpose of this study was to determine whether AD patients have difficulty maintaining upright balance under absent and/or incongruent visual and other sensory conditions compared to nondemented healthy elderly persons and individuals with Parkinson's disease (PD). Seventeen healthy older adults, 15 medicated PD subjects, and 11 AD subjects underwent the Sensory Organization Test protocol. The incidence of loss of balance ("falls"), and the peak-to-peak amplitude of body center of mass sway during stance in the six sensory conditions were used to infer the ability to use visual, somatosensory, and vestibular signals when they provided useful information for balance, and to suppress them when they were incongruent as an orientation reference. Vestibular reflex tests were conducted to ensure normal vestibular function in the subjects. AD subjects had normal vestibular function but had trouble using it in condition 6, where they had to concurrently suppress both incongruent visual and somatosensory inputs. All 11 AD subjects fell in the first trial of this condition. With repeated trials, only three AD subjects were able to stay balanced. AD subjects were able to keep their balance when only somatosensory input was incongruent. In this condition, all AD subjects were able to maintain balance whereas some falls occurred in the other groups. In all conditions, when AD subjects did not fall, they were able to control as large a sway as the healthy controls, except when standing with eyes closed in condition 2: AD subjects did not increase their sway whereas the other groups did. In the PD group, the total fall incidence was similar to the AD group, but the distribution was generalized across more sensory conditions. PD subjects were also able to improve with repeated trials in condition 6. Patients with dementia of the Alzheimer type have decreased ability to suppress incongruent visual stimuli when trying to maintain balance. However, they did not seem to be dependent on vision for balance because they did not increase their sway when vision was absent. Parkinsonian patients have a more general balance control problem in the sensory organization test, possibly related to difficulty changing set.

Effects of Various Warm Up Protocol on Special Judo Fitness Test Performance.

PubMed

Lum, Danny

2017-02-13

The purposed of this study was to compare the effects of postactivation potentiation (PAP) on Special Judo Fitness Test (SJFT) performance using explosive exercises that activates upper and lower limbs muscles. Eleven male judo athletes (mean ± SD, age, 16 - 29 years; height, 170 ± 7 cm; body mass, 73 ± 16 kg) attended four separate sessions. The first session was used to familiarise the subjects to the experimental procedure, the SJFT, the high pull test (HPT) and the two explosive exercises including resistance band pull and standing broad jump. Subsequently, subjects were randomly assigned in a counterbalanced manner to either perform the upper and lower body PAP (ULB), lower body PAP (LB) or usual competition (CON) warm up routine prior to performing the HPT and SJFT. The following variables were quantified: throws performed during series A, B, and C; total number of throws; heart rate immediately and 1 minute after the test; test index; peak power; and RPE after warm up. During series 1, number of throws performed in LB and ULB were significantly greater than CON (p < 0.05). Only ULB resulted in significantly greater number of total throws (p < 0.01) and higher peak power (p < 0.01) than CON. The RPE for both LB and ULB were significantly lower than CON (p < 0.01). Peak power was moderately correlated to total number of throws performed (r=0.4, p < 0.05). This study suggest that performing ULB before SJFT can result in improved performance and peak power.

ESR study of free radicals in mango

NASA Astrophysics Data System (ADS)

Kikuchi, Masahiro; Hussain, Mohammad S.; Morishita, Norio; Ukai, Mitsuko; Kobayashi, Yasuhiko; Shimoyama, Yuhei

2010-01-01

An electron spin resonance (ESR) spectroscopic study of radicals induced in irradiated fresh mangoes was performed. Mangoes in the fresh state were irradiated with γ-rays, lyophilized and then crushed into a powder. The ESR spectrum of the powder showed a strong main peak at g = 2.004 and a pair of peaks centered at the main peak. The main peak was detected from both flesh and skin specimens. This peak height gradually decreased during storage following irradiation. On the other hand, the side peaks showed a well-defined dose-response relationship even at 9 days post-irradiation. The side peaks therefore provide a useful means to define the irradiation of fresh mangoes.

Minimizing masses in explosively driven two-shockwave physics applications

NASA Astrophysics Data System (ADS)

Buttler, William; Cherne, Frank; Furlanetto, Michael; Payton, Jeremy; Stone, Joseph; Tabaka, Leonard; Vincent, Samuel

2015-06-01

We have experimentally investigated different two-shockwave high-explosives (HE) physics package designs to maximize the variability of the second shockwave peak stress, while minimizing the total HE load of the physics tool. A critical requirement is to also have a large radial diameter of the second shockwave to maintain its value as an HE driven two-shockwave drive. We have previously shown that we could vary the peak-stress of the second-shockwave with a 76 mm diameter HE lens driving different composite boosters of PBX 9501 and TNT. Here we report on our results with a 56- and 50-mm diameter HE lens driving Baritol. The results indicate that the 56-mm diameter HE lens works well, as does the Baritol, giving total HE loads of about 250 mg TNT equivalent explosives.

Effect of antacids on predicted steady-state cimetidine concentrations.

PubMed

Russell, W L; Lopez, L M; Normann, S A; Doering, P L; Guild, R T

1984-05-01

The purpose of this study was to evaluate effects of antacids on predicted steady-state concentrations of cimetidine. Ten healthy volunteers received in random order one week apart, cimetidine and cimetidine and antacid suspension. Blood was obtained at specified times and analyzed for cimetidine. Bioavailability was assessed by comparison of peak concentration, time to peak concentration, area under the curve, and time spent over 0.5 micrograms/ml. Single-dose data were extrapolated to steady-state using computer simulation. Concurrent administration of antacid suspension reduced parameters of bioavailability approximately 30%. When steady-state conditions were simulated, concentrations of cimetidine greater than or equal to 0.5 micrograms/ml were maintained for the entire dosing interval in seven of 10 subjects. These data suggest that temporal separation of cimetidine and antacid suspension may be unnecessary.

Reductions in Sprint Paddling Ability and Countermovement Jump Performance After Surfing Training.

PubMed

Secomb, Josh L; Sheppard, Jeremy M; Dascombe, Ben J

2015-07-01

The present study aimed to determine whether any meaningful change in a surfer's sprint paddling ability and countermovement jump (CMJ) performance developed after a 2-hour surfing training session and also whether any physical demands of the surfing session were related to the resultant changes in the capacities. Fifteen competitive male surfing athletes (age, 22.1 ± 3.9 years; height, 175.4 ± 6.4 cm; body mass, 72.5 ± 7.7 kg) performed a 2-hour surfing training session, with 15-m sprint paddle and CMJ trials performed both before and after the surfing session. Pre- to posttesting measures were analyzed using magnitude-based inferences. Likely declines were observed in the velocity achieved at the 5-, 10-, and 15-m splits of the 15-m sprint paddle, as well as peak velocity. Similarly, likely declines were calculated for CMJ peak force, relative peak force, and jump height. Furthermore, large correlations were calculated between presurfing session peak velocity and the change in 5, 10, 15 m, and peak velocity of the 15-m sprint paddle and total distance covered, wave riding bouts, and success rate. Surfing athletes and coaches may need to consider implementing shorter duration training sessions to reduce the decline in sprint paddling ability and CMJ performance. Furthermore, surfing athletes should possess highly developed sprint paddling ability because this may allow them to undertake a greater workload and catch more waves, which will increase the opportunity for technical refinement of maneuvers and skill acquisition.

Effect of gear ratio on peak power and time to peak power in BMX cyclists.

PubMed

Rylands, Lee P; Roberts, Simon J; Hurst, Howard T

2017-03-01

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders' bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14) = 6.448; p = .010) and peak torque (F(2,14) = 4.777; p = .026), but no significant difference was found for time to peak power (F(2,14) = 0.200; p = .821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658 ± 221 W, compared to 1436 ± 129 W and 1380 ± 56 W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in -0.01 s and a 45/16 in 0.22 s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.

A test of fixed and moving reference point control in posture.

PubMed

Lee, I-Chieh; Pacheco, Matheus M; Newell, Karl M

2017-01-01

This study investigated two contrasting assumptions of the regulation of posture: namely, fixed and moving reference point control. These assumptions were tested in terms of time-dependent structure and data distribution properties when stability is manipulated. Fifteen male participants performed a tightrope simulated balance task that is, maintaining a tandem stance while holding a pole. Pole length (and mass) and the standing support surface (fixed surface/balance board) were manipulated so as to mechanically change the balance stability. The mean and standard deviation (SD) of COP length were reduced with pole length increment but only in the balance board surface condition. Also, the SampEn was lower with greater pole length for the balance board but not the fixed surface. More than one peak was present in the distribution of COP in the majority of trials. Collectively, the findings provide evidence for a moving reference point in the maintenance of postural stability for quiet standing. Copyright © 2016 Elsevier B.V. All rights reserved.

Decompression-Driven Superconductivity Enhancement in In2 Se3.

PubMed

Ke, Feng; Dong, Haini; Chen, Yabin; Zhang, Jianbo; Liu, Cailong; Zhang, Junkai; Gan, Yuan; Han, Yonghao; Chen, Zhiqiang; Gao, Chunxiao; Wen, Jinsheng; Yang, Wenge; Chen, Xiao-Jia; Struzhkin, Viktor V; Mao, Ho-Kwang; Chen, Bin

2017-09-01

An unexpected superconductivity enhancement is reported in decompressed In 2 Se 3 . The onset of superconductivity in In 2 Se 3 occurs at 41.3 GPa with a critical temperature (T c ) of 3.7 K, peaking at 47.1 GPa. The striking observation shows that this layered chalcogenide remains superconducting in decompression down to 10.7 GPa. More surprisingly, the highest T c that occurs at lower decompression pressures is 8.2 K, a twofold increase in the same crystal structure as in compression. It is found that the evolution of T c is driven by the pressure-induced R-3m to I-43d structural transition and significant softening of phonons and gentle variation of carrier concentration combined in the pressure quench. The novel decompression-induced superconductivity enhancement implies that it is possible to maintain pressure-induced superconductivity at lower or even ambient pressures with better superconducting performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultra-high efficiency moving wire combustion interface for on-line coupling of HPLC

PubMed Central

Thomas, Avi T.; Ognibene, Ted; Daley, Paul; Turteltaub, Ken; Radousky, Harry; Bench, Graham

2011-01-01

We describe a 100% efficient moving-wire interface for on-line coupling of high performance liquid chromatography which transmits 100% of carbon in non-volatile analytes to a CO2 gas accepting ion source. This interface accepts a flow of analyte in solvent, evaporates the solvent, combusts the remaining analyte, and directs the combustion products to the instrument of choice. Effluent is transferred to a periodically indented wire by a coherent jet to increase efficiency and maintain peak resolution. The combustion oven is plumbed such that gaseous combustion products are completely directed to an exit capillary, avoiding the loss of combustion products to the atmosphere. This system achieves the near complete transfer of analyte at HPLC flow rates up to 125 μL/min at a wire speed of 6 cm/s. This represents a 30x efficiency increase and 8x maximum wire loading compared to the spray transfer technique used in earlier moving wire interfaces. PMID:22004428

Maximising Longwall performance and profitability by the introduction of moving car bunker systems into outbye haulage layouts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barlow, P.M.

1996-12-31

In order to maximize the profitability of Longwall mining operations, outbye materials handling systems should be cost effectively engineered to both fully harmonize with cyclical surges in output and to maintain high levels of availability. With the introduction of new Longwall systems into existing mines, the upgrading of outbye haulage to handle peak production from the Longwall panel can prove to be extremely expensive and is often unnecessary. In addition, despite high levels of investment in new equipment, many mines are still failing to achieve planned gains in Longwall productivity due to persistent downtime on outbye haulage routes. This papermore » details the planning, production and engineering considerations necessary to maximize profitability by the introduction of moving car bunker systems to underground haulage layouts. It also examines case studies of recent installations within the North American coal mining industry and charts the significant success being achieved in improving profitability at these mines.« less

Modeling and simulation of consumer response to dynamic pricing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valenzuela, J.; Thimmapuram, P.; Kim, J

2012-08-01

Assessing the impacts of dynamic-pricing under the smart grid concept is becoming extremely important for deciding its full deployment. In this paper, we develop a model that represents the response of consumers to dynamic pricing. In the model, consumers use forecasted day-ahead prices to shift daily energy consumption from hours when the price is expected to be high to hours when the price is expected to be low while maintaining the total energy consumption as unchanged. We integrate the consumer response model into the Electricity Market Complex Adaptive System (EMCAS). EMCAS is an agent-based model that simulates restructured electricity markets.more » We explore the impacts of dynamic-pricing on price spikes, peak demand, consumer energy bills, power supplier profits, and congestion costs. A simulation of an 11-node test network that includes eight generation companies and five aggregated consumers is performed for a period of 1 month. In addition, we simulate the Korean power system.« less

FRAPCON analysis of cladding performance during dry storage operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richmond, David J.; Geelhood, Kenneth J.

There is an increasing need in the U.S. and around the world to move used nuclear fuel from wet storage in fuel pools to dry storage in casks stored at independent spent fuel storage installations (ISFSI) or interim storage sites. The NRC limits cladding temperature to 400°C while maintaining cladding hoop stress below 90 MPa in an effort to avoid radial hydride reorientation. An analysis was conducted with FRAPCON-4.0 on three modern fuel designs with three representative used nuclear fuel storage temperature profiles that peaked at 400 °C. Results were representative of the majority of U.S. LWR fuel. They conservativelymore » showed that hoop stress remains below 90 MPa at the licensing temperature limit. Results also show that the limiting case for hoop stress may not be at the highest rod internal pressure in all cases but will be related to the axial temperature and oxidation profiles of the rods at the end of life and in storage.« less

Acclimatization and tolerance to extreme altitude

NASA Technical Reports Server (NTRS)

West, J. B.

1993-01-01

During the last ten years, two major experiments have elucidated the factors determining acclimatization and tolerance to extreme altitude (over 7000 m). These were the American Medical Research Expedition to Everest, and the low pressure chamber simulation, Operation Everest II. Extreme hyperventilation is one of the most important responses to extreme altitude. Its chief value is that it allows the climber to maintain an alveolar PO2 which keeps the arterial PO2 above dangerously low levels. Even so, there is evidence of residual impairment of central nervous system function after ascents to extreme altitude, and maximal oxygen consumption falls precipitously above 7000 m. The term 'acclimatization' is probably not appropriate for altitudes above 8000 m, because the body steadily deteriorates at these altitudes. Tolerance to extreme altitude is critically dependent on barometric pressure, and even seasonal changes in pressure probably affect climbing performance near the summit of Mt Everest. Supplementary oxygen always improves exercise tolerance at extreme altitudes, and rescue oxygen should be available on climbing expeditions to 8000 m peaks.

Analysis of electric field distribution in GaAs metal-semiconductor field effect transistor with a field-modulating plate

NASA Astrophysics Data System (ADS)

Hori, Yasuko; Kuzuhara, Masaaki; Ando, Yuji; Mizuta, Masashi

2000-04-01

Electric field distribution in the channel of a field effect transistor (FET) with a field-modulating plate (FP) has been theoretically investigated using a two-dimensional ensemble Monte Carlo simulation. This analysis revealed that the introduction of FP is effective in canceling the influence of surface traps under forward bias conditions and in reducing the electric field intensity at the drain side of the gate edge under pinch-off bias conditions. This study also found that a partial overlap of the high-field region under the gate and that at the FP electrode is important for reducing the electric field intensity. The optimized metal-semiconductor FET with FP (FPFET) (LGF˜0.2 μm) exhibited a much lower peak electric field intensity than a conventional metal-semiconductor FET. Based on these numerically calculated results, we have proposed a design procedure to optimize the power FPFET structure with extremely high breakdown voltages while maintaining reasonable gain performance.

Phenol-degrading anode biofilm with high coulombic efficiency in graphite electrodes microbial fuel cell.

PubMed

Zhang, Dongdong; Li, Zhiling; Zhang, Chunfang; Zhou, Xue; Xiao, Zhixing; Awata, Takanori; Katayama, Arata

2017-03-01

A microbial fuel cell (MFC), with graphite electrodes as both the anode and cathode, was operated with a soil-free anaerobic consortium for phenol degradation. This phenol-degrading MFC showed high efficiency with a current density of 120 mA/m 2 and a coulombic efficiency of 22.7%, despite the lack of a platinum catalyst cathode and inoculation of sediment/soil. Removal of planktonic bacteria by renewing the anaerobic medium did not decrease the performance, suggesting that the phenol-degrading MFC was not maintained by the planktonic bacteria but by the microorganisms in the anode biofilm. Cyclic voltammetry analysis of the anode biofilm showed distinct oxidation and reduction peaks. Analysis of the microbial community structure of the anode biofilm and the planktonic bacteria based on 16S rRNA gene sequences suggested that Geobacter sp. was the phenol degrader in the anode biofilm and was responsible for current generation. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Hydrophobicity and leakage current statistics of polymeric insulators long-term exposed to coastal contamination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soerqvist, T.; Vlastos, A.E.

1996-12-31

The hydrophobicity of polymeric insulators is crucial for their performance. This paper reports the hydrophobicity and the peak leakage current statistics of one porcelain, two ethylene-propylene-diene monomer (EPDM) and four silicone rubber (SIR) commercially available insulators. The insulators have been energized with 130 kV rms phase-to-ground AC voltage under identical outdoor conditions for more than seven years. The results presented show that under wet and polluted conditions the hydrophilic EPDM rubber insulators develop high leakage currents and substantial arcing. During a typical salt-storm the arcing amplitude of the EPDM rubber insulators is at least twice as high as that ofmore » the porcelain insulator. The SIR insulators, on the other hand, preserve a high degree of hydrophobicity after more than seven years in service and maintain very low leakage currents. However, the results show that during heavy salt contaminated conditions a highly stressed SIR insulator can temporarily lose its hydrophobicity and thereby develop considerable surface arcing.« less

Acoustic waves in M dwarfs: Maintaining a corona

NASA Technical Reports Server (NTRS)

Mullan, D. J.; Cheng, Q. Q.

1994-01-01

We use a time-dependent hydrodynamics code to follow the propagation of acoustic waves into the corona of an M dwarf star. An important qualitative difference between M dwarfs and stars such as the Sun is that the acoustic spectrum in M dwarfs is expected to peak at periods close to the acoustic cutoff P(sub A): this allows more effective penetration of waves into the corona. In our code, radiative losses in the photosphere, chromosphere, and corona are computed using Rosseland mean opacities, Mg II kappa and Ly alpha emission, and optically thin emissivities respectively. We find that acoustic heating can maintain a corona with a temperature of order 0.7-1 x 10(exp 6) K and a surface X-ray flux as large as 10(exp 5)ergs/sq cm/s. In a recent survey of X-rays from M dwarfs, some (20%-30%) of the stars lie at or below this limiting X-ray flux: we suggest that such stars may be candidates for acoustically maintained coronae.

Age-related differences in lower-limb force-time relation during the push-off in rapid voluntary stepping.

PubMed

Melzer, I; Krasovsky, T; Oddsson, L I E; Liebermann, D G

2010-12-01

This study investigated the force-time relationship during the push-off stage of a rapid voluntary step in young and older healthy adults, to study the assumption that when balance is lost a quick step may preserve stability. The ability to achieve peak propulsive force within a short time is critical for the performance of such a quick powerful step. We hypothesized that older adults would achieve peak force and power in significantly longer times compared to young people, particularly during the push-off preparatory phase. Fifteen young and 15 older volunteers performed rapid forward steps while standing on a force platform. Absolute anteroposterior and body weight normalized vertical forces during the push-off in the preparation and swing phases were used to determine time to peak and peak force, and step power. Two-way analyses of variance ('Group' [young-older] by 'Phase' [preparation-swing]) were used to assess our hypothesis (P ≤ 0.05). Older people exerted lower peak forces (anteroposterior and vertical) than young adults, but not necessarily lower peak power. More significantly, they showed a longer time to peak force, particularly in the vertical direction during the preparation phase. Older adults generate propulsive forces slowly and reach lower magnitudes, mainly during step preparation. The time to achieve a peak force and power, rather than its actual magnitude, may account for failures in quickly performing a preventive action. Such delay may be associated with the inability to react and recruit muscles quickly. Thus, training elderly to step fast in response to relevant cues may be beneficial in the prevention of falls. Copyright © 2010 Elsevier Ltd. All rights reserved.

Peak Detection Method Evaluation for Ion Mobility Spectrometry by Using Machine Learning Approaches

PubMed Central

Hauschild, Anne-Christin; Kopczynski, Dominik; D’Addario, Marianna; Baumbach, Jörg Ingo; Rahmann, Sven; Baumbach, Jan

2013-01-01

Ion mobility spectrometry with pre-separation by multi-capillary columns (MCC/IMS) has become an established inexpensive, non-invasive bioanalytics technology for detecting volatile organic compounds (VOCs) with various metabolomics applications in medical research. To pave the way for this technology towards daily usage in medical practice, different steps still have to be taken. With respect to modern biomarker research, one of the most important tasks is the automatic classification of patient-specific data sets into different groups, healthy or not, for instance. Although sophisticated machine learning methods exist, an inevitable preprocessing step is reliable and robust peak detection without manual intervention. In this work we evaluate four state-of-the-art approaches for automated IMS-based peak detection: local maxima search, watershed transformation with IPHEx, region-merging with VisualNow, and peak model estimation (PME). We manually generated a gold standard with the aid of a domain expert (manual) and compare the performance of the four peak calling methods with respect to two distinct criteria. We first utilize established machine learning methods and systematically study their classification performance based on the four peak detectors’ results. Second, we investigate the classification variance and robustness regarding perturbation and overfitting. Our main finding is that the power of the classification accuracy is almost equally good for all methods, the manually created gold standard as well as the four automatic peak finding methods. In addition, we note that all tools, manual and automatic, are similarly robust against perturbations. However, the classification performance is more robust against overfitting when using the PME as peak calling preprocessor. In summary, we conclude that all methods, though small differences exist, are largely reliable and enable a wide spectrum of real-world biomedical applications. PMID:24957992

Peak detection method evaluation for ion mobility spectrometry by using machine learning approaches.

PubMed

Hauschild, Anne-Christin; Kopczynski, Dominik; D'Addario, Marianna; Baumbach, Jörg Ingo; Rahmann, Sven; Baumbach, Jan

2013-04-16

Ion mobility spectrometry with pre-separation by multi-capillary columns (MCC/IMS) has become an established inexpensive, non-invasive bioanalytics technology for detecting volatile organic compounds (VOCs) with various metabolomics applications in medical research. To pave the way for this technology towards daily usage in medical practice, different steps still have to be taken. With respect to modern biomarker research, one of the most important tasks is the automatic classification of patient-specific data sets into different groups, healthy or not, for instance. Although sophisticated machine learning methods exist, an inevitable preprocessing step is reliable and robust peak detection without manual intervention. In this work we evaluate four state-of-the-art approaches for automated IMS-based peak detection: local maxima search, watershed transformation with IPHEx, region-merging with VisualNow, and peak model estimation (PME).We manually generated Metabolites 2013, 3 278 a gold standard with the aid of a domain expert (manual) and compare the performance of the four peak calling methods with respect to two distinct criteria. We first utilize established machine learning methods and systematically study their classification performance based on the four peak detectors' results. Second, we investigate the classification variance and robustness regarding perturbation and overfitting. Our main finding is that the power of the classification accuracy is almost equally good for all methods, the manually created gold standard as well as the four automatic peak finding methods. In addition, we note that all tools, manual and automatic, are similarly robust against perturbations. However, the classification performance is more robust against overfitting when using the PME as peak calling preprocessor. In summary, we conclude that all methods, though small differences exist, are largely reliable and enable a wide spectrum of real-world biomedical applications.

Ionospheric Peak Electron Density and Performance Evaluation of IRI-CCIR Near Magnetic Equator in Africa During Two Extreme Solar Activities

NASA Astrophysics Data System (ADS)

Adebesin, B. O.; Rabiu, A. B.; Obrou, O. K.; Adeniyi, J. O.

2018-03-01

The F2 layer peak electron density (NmF2) was investigated over Korhogo (Geomagnetic: 1.26°S, 67.38°E), a station near the magnetic equator in the African sector. Data for 1996 and 2000 were, respectively, categorized into low solar quiet and disturbed and high solar quiet and disturbed. NmF2 prenoon peak was higher than the postnoon peak during high solar activity irrespective of magnetic activity condition, while the postnoon peak was higher for low solar activity. Higher NmF2 peak amplitude characterizes disturbed magnetic activity than quiet magnetic condition for any solar activity. The maximum peaks appeared in equinox. June solstice noontime bite out lagged other seasons by 1-2 h. For any condition of solar and magnetic activities, the daytime NmF2 percentage variability (%VR) measured by the relative standard deviation maximizes/minimizes in June solstice/equinox. Daytime variability increases with increasing magnetic activity. The highest peak in the morning time NmF2 variability occurs in equinox, while the highest evening/nighttime variability appeared in June solstice for all solar/magnetic conditions. The nighttime annual variability amplitude is higher during disturbed than quiet condition regardless of solar activity period. At daytime, variability is similar for all conditions of solar activities. NmF2 at Korhogo is well represented on the International Reference Ionosphere-International Radio Consultative Committee (IRI-CCIR) option. The model/observation relationship performed best between local midnight and postmidnight period (00-08 LT). The noontime trough characteristics is not prominent in the IRI pattern during high solar activity but evident during low solar conditions when compared with Korhogo observations. The Nash-Sutcliffe coefficients revealed better model performance during disturbed activities.

Optimization of Region of Interest Drawing for Quantitative Analysis: Differentiation Between Benign and Malignant Breast Lesions on Contrast-Enhanced Sonography.

PubMed

Nakata, Norio; Ohta, Tomoyuki; Nishioka, Makiko; Takeyama, Hiroshi; Toriumi, Yasuo; Kato, Kumiko; Nogi, Hiroko; Kamio, Makiko; Fukuda, Kunihiko

2015-11-01

This study was performed to evaluate the diagnostic utility of quantitative analysis of benign and malignant breast lesions using contrast-enhanced sonography. Contrast-enhanced sonography using the perflubutane-based contrast agent Sonazoid (Daiichi Sankyo, Tokyo, Japan) was performed in 94 pathologically proven palpable breast mass lesions, which could be depicted with B-mode sonography. Quantitative analyses using the time-intensity curve on contrast-enhanced sonography were performed in 5 region of interest (ROI) types (manually traced ROI and circular ROIs of 5, 10, 15, and 20 mm in diameter). The peak signal intensity, initial slope, time to peak, positive enhancement integral, and wash-out ratio were investigated in each ROI. There were significant differences between benign and malignant lesions in the time to peak (P < .05), initial slope (P < .001), and positive enhancement integral (P < .05) for the manual ROI. Significant differences were found between benign and malignant lesions in the time to peak (P < .05) for the 5-mm ROI; the time to peak (P < .05) and initial slope (P< .05) for the 10-mm ROI; absolute values of the peak signal intensity (P< .05), time to peak (P< .01), and initial slope (P< .005) for the 15-mm ROI; and the time to peak (P < .05) and initial slope (P < .05) for the 20-mm ROI. There were no statistically significant differences in any wash-out ratio values for the 5 ROI types. Kinetic analysis using contrast-enhanced sonography is useful for differentiation between benign and malignant breast lesions. © 2015 by the American Institute of Ultrasound in Medicine.

Oxygen uptake during functional activities after stroke—Reliability and validity of a portable ergospirometry system

PubMed Central

Brurok, Berit; Tjønna, Arnt Erik; Tørhaug, Tom; Askim, Torunn

2017-01-01

Background People with stroke have a low peak aerobic capacity and experience increased effort during performance of daily activities. The purpose of this study was to examine test-retest reliability of a portable ergospirometry system in people with stroke during performance of functional activities in a field-test. Secondary aims were to examine the proportion of oxygen consumed during the field-test in relation to the peak-test and to analyse the correlation between the oxygen uptake during the field-test and peak-test in order to support the validity of the field-test. Methods With simultaneous measurement of oxygen consumption, participants performed a standardized field-test consisting of five activities; walking over ground, stair walking, stepping over obstacles, walking slalom between cones and from a standing position lifting objects from one height to another. All activities were performed in self-selected speed. Prior to the field-test, a peak aerobic capacity test was performed. The field-test was repeated minimum 2 and maximum 14 days between the tests. ICC2,1 and Bland Altman tests (Limits of Agreement, LoA) were used to analyse test-retest reliability. Results In total 31 participants (39% women, mean (SD) age 54.5 (12.7) years and 21.1 (14.3) months’ post-stroke) were included. The ICC2,1 was ≥ 0.80 for absolute V̇O2, relative V̇O2, minute ventilation, CO2, respiratory exchange ratio, heart rate and Borgs rating of perceived exertion. ICC2,1 for total time to complete the field-test was 0.99. Mean difference in steady state V̇O2 during Test 1 and Test 2 was -0.40 (2.12) The LoAs were -3.75 and 4.51. Participants spent 60.7% of their V̇O2peak performing functional activities. Correlation between field-test and peak-test was 0.689, p = 0.001 for absolute and 0.733, p = 0.001 for relative V̇O2. Conclusions This study presents first evidence on reliability of oxygen uptake during performance of functional activities after stroke, showing very good test-retest reliability. The secondary analysis showed that the amount of energy spent during the field-test relative to the peak-test was high and the correlation between the two test was good, supporting the validity of this method. PMID:29065164

The development and functional control of reading-comprehension behavior.

PubMed

Rosenbaum, M S; Breiling, J

1976-01-01

Reading comprehension, indicated by motor behavior and multiple-choice picture selection called for in written instructions, was taught to an autistic child using verbal prompts, modelling, and physical guidance. The child was rewarded for correct behaviors to training items; nonrewarded probes were used to assess generalization. Probable maintaining events were assessed through their sequential removal in a reversal design. Results showed: (a) following acquisition, performance was maintained at a near-100% level when candy, praise, attention, and training were removed, (b) absence of other persons was correlated with a marked decrease in performance, whereas their presence was associated with performance at near 100%, and (c) performance generalized to probes and across experimenters. Rewards, which may have been reinforcing during acquisition, did not appear necessary to maintain later performance. Instead, presence of others (a setting event) was demonstrated to have control over maintained performance.

MS-REDUCE: an ultrafast technique for reduction of big mass spectrometry data for high-throughput processing.

PubMed

Awan, Muaaz Gul; Saeed, Fahad

2016-05-15

Modern proteomics studies utilize high-throughput mass spectrometers which can produce data at an astonishing rate. These big mass spectrometry (MS) datasets can easily reach peta-scale level creating storage and analytic problems for large-scale systems biology studies. Each spectrum consists of thousands of peaks which have to be processed to deduce the peptide. However, only a small percentage of peaks in a spectrum are useful for peptide deduction as most of the peaks are either noise or not useful for a given spectrum. This redundant processing of non-useful peaks is a bottleneck for streaming high-throughput processing of big MS data. One way to reduce the amount of computation required in a high-throughput environment is to eliminate non-useful peaks. Existing noise removing algorithms are limited in their data-reduction capability and are compute intensive making them unsuitable for big data and high-throughput environments. In this paper we introduce a novel low-complexity technique based on classification, quantization and sampling of MS peaks. We present a novel data-reductive strategy for analysis of Big MS data. Our algorithm, called MS-REDUCE, is capable of eliminating noisy peaks as well as peaks that do not contribute to peptide deduction before any peptide deduction is attempted. Our experiments have shown up to 100× speed up over existing state of the art noise elimination algorithms while maintaining comparable high quality matches. Using our approach we were able to process a million spectra in just under an hour on a moderate server. The developed tool and strategy has been made available to wider proteomics and parallel computing community and the code can be found at https://github.com/pcdslab/MSREDUCE CONTACT: : fahad.saeed@wmich.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Two-station comparison of peak flows to improve flood-frequency estimates for seven streamflow-gaging stations in the Salmon and Clearwater River Basins, Central Idaho

USGS Publications Warehouse

Berenbrock, Charles

2003-01-01

Improved flood-frequency estimates for short-term (10 or fewer years of record) streamflow-gaging stations were needed to support instream flow studies by the U.S. Forest Service, which are focused on quantifying water rights necessary to maintain or restore productive fish habitat. Because peak-flow data for short-term gaging stations can be biased by having been collected during an unusually wet, dry, or otherwise unrepresentative period of record, the data may not represent the full range of potential floods at a site. To test whether peak-flow estimates for short-term gaging stations could be improved, the two-station comparison method was used to adjust the logarithmic mean and logarithmic standard deviation of peak flows for seven short-term gaging stations in the Salmon and Clearwater River Basins, central Idaho. Correlation coefficients determined from regression of peak flows for paired short-term and long-term (more than 10 years of record) gaging stations over a concurrent period of record indicated that the mean and standard deviation of peak flows for all short-term gaging stations would be improved. Flood-frequency estimates for seven short-term gaging stations were determined using the adjusted mean and standard deviation. The original (unadjusted) flood-frequency estimates for three of the seven short-term gaging stations differed from the adjusted estimates by less than 10 percent, probably because the data were collected during periods representing the full range of peak flows. Unadjusted flood-frequency estimates for four short-term gaging stations differed from the adjusted estimates by more than 10 percent; unadjusted estimates for Little Slate Creek and Salmon River near Obsidian differed from adjusted estimates by nearly 30 percent. These large differences probably are attributable to unrepresentative periods of peak-flow data collection.

Comparison of dissimilarity measures for cluster analysis of X-ray diffraction data from combinatorial libraries

NASA Astrophysics Data System (ADS)

Iwasaki, Yuma; Kusne, A. Gilad; Takeuchi, Ichiro

2017-12-01

Machine learning techniques have proven invaluable to manage the ever growing volume of materials research data produced as developments continue in high-throughput materials simulation, fabrication, and characterization. In particular, machine learning techniques have been demonstrated for their utility in rapidly and automatically identifying potential composition-phase maps from structural data characterization of composition spread libraries, enabling rapid materials fabrication-structure-property analysis and functional materials discovery. A key issue in development of an automated phase-diagram determination method is the choice of dissimilarity measure, or kernel function. The desired measure reduces the impact of confounding structural data issues on analysis performance. The issues include peak height changes and peak shifting due to lattice constant change as a function of composition. In this work, we investigate the choice of dissimilarity measure in X-ray diffraction-based structure analysis and the choice of measure's performance impact on automatic composition-phase map determination. Nine dissimilarity measures are investigated for their impact in analyzing X-ray diffraction patterns for a Fe-Co-Ni ternary alloy composition spread. The cosine, Pearson correlation coefficient, and Jensen-Shannon divergence measures are shown to provide the best performance in the presence of peak height change and peak shifting (due to lattice constant change) when the magnitude of peak shifting is unknown. With prior knowledge of the maximum peak shifting, dynamic time warping in a normalized constrained mode provides the best performance. This work also serves to demonstrate a strategy for rapid analysis of a large number of X-ray diffraction patterns in general beyond data from combinatorial libraries.

Sustained eruptions on Enceladus explained by turbulent dissipation in tiger stripes

NASA Astrophysics Data System (ADS)

Kite, Edwin S.; Rubin, Allan M.

2016-04-01

Spacecraft observations suggest that the plumes of Saturn’s moon Enceladus draw water from a subsurface ocean, but the sustainability of conduits linking ocean and surface is not understood. Observations show eruptions from “tiger stripe” fissures that are sustained (although tidally modulated) throughout each orbit, and since the 2005 discovery of the plumes. Peak plume flux lags peak tidal extension by ˜1 rad, suggestive of resonance. Here, we show that a model of the tiger stripes as tidally flexed slots that puncture the ice shell can simultaneously explain the persistence of the eruptions through the tidal cycle, the phase lag, and the total power output of the tiger stripe terrain, while suggesting that eruptions are maintained over geological timescales. The delay associated with flushing and refilling of O(1)-m-wide slots with ocean water causes erupted flux to lag tidal forcing and helps to buttress slots against closure, while tidally pumped in-slot flow leads to heating and mechanical disruption that staves off slot freezeout. Much narrower and much wider slots cannot be sustained. In the presence of long-lived slots, the 106-y average power output of the tiger stripes is buffered by a feedback between ice melt-back and subsidence to O(1010) W, which is similar to observed power output, suggesting long-term stability. Turbulent dissipation makes testable predictions for the final flybys of Enceladus by Cassini. Our model shows how open connections to an ocean can be reconciled with, and sustain, long-lived eruptions. Turbulent dissipation in long-lived slots helps maintain the ocean against freezing, maintains access by future Enceladus missions to ocean materials, and is plausibly the major energy source for tiger stripe activity.

Dynamic Response of an Optomechanical System to a Stationary Random Excitation in the Time Domain

DOE PAGES

Palmer, Jeremy A.; Paez, Thomas L.

2011-01-01

Modern electro-optical instruments are typically designed with assemblies of optomechanical members that support optics such that alignment is maintained in service environments that include random vibration loads. This paper presents a nonlinear numerical analysis that calculates statistics for the peak lateral response of optics in an optomechanical sub-assembly subject to random excitation of the housing. The work is unique in that the prior art does not address peak response probability distribution for stationary random vibration in the time domain for a common lens-retainer-housing system with Coulomb damping. Analytical results are validated by using displacement response data from random vibration testingmore » of representative prototype sub-assemblies. A comparison of predictions to experimental results yields reasonable agreement. The Type I Asymptotic form provides the cumulative distribution function for peak response probabilities. Probabilities are calculated for actual lens centration tolerances. The probability that peak response will not exceed the centration tolerance is greater than 80% for prototype configurations where the tolerance is high (on the order of 30 micrometers). Conversely, the probability is low for those where the tolerance is less than 20 micrometers. The analysis suggests a design paradigm based on the influence of lateral stiffness on the magnitude of the response.« less

Stimulus generalization, discrimination learning, and peak shift in horses.

PubMed Central

Dougherty, D M; Lewis, P

1991-01-01

Using horses, we investigated three aspects of the stimulus control of lever-pressing behavior: stimulus generalization, discrimination learning, and peak shift. Nine solid black circles, ranging in size from 0.5 in. to 4.5 in. (1.3 cm to 11.4 cm) served as stimuli. Each horse was shaped, using successive approximations, to press a rat lever with its lip in the presence of a positive stimulus, the 2.5-in. (6.4-cm) circle. Shaping proceeded quickly and was comparable to that of other laboratory organisms. After responding was maintained on a variable-interval 30-s schedule, stimulus generalization gradients were collected from 2 horses prior to discrimination training. During discrimination training, grain followed lever presses in the presence of a positive stimulus (a 2.5-in circle) and never followed lever presses in the presence of a negative stimulus (a 1.5-in. [3.8-cm] circle). Three horses met a criterion of zero responses to the negative stimulus in fewer than 15 sessions. Horses given stimulus generalization testing prior to discrimination training produced symmetrical gradients; horses given discrimination training prior to generalization testing produced asymmetrical gradients. The peak of these gradients shifted away from the negative stimulus. These results are consistent with discrimination, stimulus generalization, and peak-shift phenomena observed in other organisms. PMID:1940765

Effect of a pulsating anti-gravity suit on peak exercise performance in individual with spinal cord injuries.

PubMed

Houtman, S; Thielen, J J; Binkhorst, R A; Hopman, M T

1999-01-01

The aim of this study was to examine effects of a pulsating pressure anti-gravity suit on the peak values of oxygen uptake (VO2) and power during maximal arm exercise in spinal-cord-injured (SCI) individuals. Five well-trained SCI men (with lesions at levels between T6 and L1) and seven well-trained able-bodied men (ABC) performed two incremental (10 W x min(-1)) arm-cranking tests. During one test the pressure in the anti-G suit pulsated between 4.7 kPa (35 mmHg) and 9.3 kPa (70 mmHg) every 2 s (PPG+), during the other test (PPG-) all the subjects wore the anti-G suit in a deflated state. Tests were performed in a counter-balanced order. Peak VO2 in SCI was 1 ml x kg(-1) x min(-1) lower during PPG+ compared to PPG- (P = 0.05). Peak power and peak heart rate were not significantly different during PPG+ compared to PPG-. These results would suggest that no increase in work capacity can be obtained with a pulsating pressure anti-gravity suit in either SCI or ABC.

Influence of dietary nitrate supplementation on physiological and cognitive responses to incremental cycle exercise.

PubMed

Thompson, Kevin G; Turner, Louise; Prichard, Jonathon; Dodd, Fiona; Kennedy, David O; Haskell, Crystal; Blackwell, James R; Jones, Andrew M

2014-03-01

Dietary inorganic nitrate supplementation causes physiological effects which may enhance exercise tolerance. However it is not known whether nitrate might alter cognitive function during exercise. In a double-blind, cross-over study, sixteen subjects ingested either nitrate-rich beetroot juice or a placebo and completed a continuous cycle exercise test involving 20min stages at 50% and 70% V˙O2peak and a final stage at 90% V˙O2peak until volitional exhaustion. Cognitive tasks were completed before, during and after exercise. In the dietary nitrate condition: plasma [nitrite] increased (p<0.01), systolic blood pressure decreased (p<0.05) and there was a trend for a reduced oxygen uptake at 50% V˙O2peak. Tissue oxygenation improved across exercise intensities and exercise tolerance was greater at 90% V˙O2peak (p<0.05). Rating of perceived exertion, energy levels and cognitive performance were similar between conditions with mental fatigue being evident from 70% V˙O2peak onwards (p<0.05). Dietary nitrate supplementation enhanced short-term endurance exercise performance with concomitant mental fatigue but did not improve cognitive performance post-fatigue. Copyright © 2014 Elsevier B.V. All rights reserved.

Isokinetic and Electromyographic Properties of Muscular Endurance in Short and Long-Term Type 2 Diabetes

PubMed Central

Hatef, Boshra; Ghanjal, Ali; Meftahi, Gholam Hossein; Askary-Ashtiani, Ahmadreza

2016-01-01

Background: Patients with type 2 diabetes mellitus (T2DM) are subject to progressive reduction of muscle mass and strength. The aim of this study was to assess muscle forces and electromyography (EMG) indices in short and long-term diabetes during an isokinetic exercise. Methods: The peak torque, work, mean power frequency (MPF) and root mean square (RMS) of knee flexors and extensors during 40 isokinetic knee extension-flexion repetitions with a velocity of 150 degree/s were recorded. 18 patients with less than 10 years with T2DM and 12 patients with equal and more than 10 years of disease were compared with 20 gender, body mass index, physical activity and peripheral circulation matched healthy controls. Results: The fatigue index and slope of line across the peak torque values of the knee flexor indicate that patients with long-term T2DM were significantly more resistant to fatigue in comparison with the two other groups (p<0.009). Whereas the MPF decrease during isokinetic protocol interact with grouping in the medial hamstring (p<0.042), but it was independent to groups in other muscles (p<0.0001). The increase of RMS after fatigue protocol interacted with sex for the medial hamstring and vastus lateralis (p<0.039) and interacted with group for the extensor muscles (p<0.045). Discussion & Conclusion: It seems that long-term T2DM cause some neuromuscular adaptations to maintain knee flexor muscle performance during functional activity especially postural control. PMID:27045412

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandage, Revati S.; McAteer, R. T. James, E-mail: mcateer@nmsu.edu

A magnetic power spectral analysis is performed on 53 solar active regions, observed from 2011 August to 2012 July. Magnetic field data obtained from the Helioseismic and Magnetic Imager, inverted as Active Region Patches, are used to study the evolution of the magnetic power index as each region rotates across the solar disk. Active regions are classified based on the numbers and sizes of solar flares they produce in order to study the relationship between flare productivity and the magnetic power index. The choice of window size and inertial range plays a key role in determining the correct magnetic powermore » index. The overall distribution of magnetic power indices has a range of 1.0–2.5. Flare-quiet regions peak at a value of 1.6. However, flare-productive regions peak at a value of 2.2. Overall, the histogram of the distribution of power indices of flare-productive active regions is well separated from flare-quiet active regions. Only 12% of flare-quiet regions exhibit an index greater than 2, whereas 90% of flare-productive regions exhibit an index greater than 2. Flare-quiet regions exhibit a high temporal variance (i.e., the index fluctuates between high and low values), whereas flare-productive regions maintain an index greater than 2 for several days. This shows the importance of including the temporal evolution of active regions in flare prediction studies, and highlights the potential of a 2–3 day prediction window for space weather applications.« less

Energy expenditure during a single-handed transatlantic yacht race.

PubMed

Myers, S D; Leamon, S M; Nevola, V R; Llewellyn, M G L

2008-04-01

The popularity of sports that expose people to consecutive days of high-intensity physical activity continues to increase. The ability to adequately nourish the human body to sustain the required level of competitive performance may be a key contributor to success in such events. The energy expenditure of a male competitor in a single-handed, transatlantic race (Transat 2004) was assessed using the doubly-labelled water technique. Mean total daily energy expenditure (TDEE) during the race (13 days) was 14.5 MJ/day with a peak expenditure of 18.6 MJ during the most physically demanding 24-hour period. This mean TDEE was approximately 25% lower than that reported in a previous study (14.5 vs. 19.3 MJ/day) for a 13-day leg of a fully crewed offshore race. The difference in results was probably due to the fact that in the previous study, the crew operated in "watches" (work shifts), affording each crew member greater opportunity to eat, rest and sleep. Effective planning and efficient management of resources is essential to the success of the solo sailor. However, the extent to which maintenance of energy balance underpins competitive success remains to be established. To maintain energy balance during the race, a mean daily energy intake of 14.5 MJ/day was necessary for the subject in this study. However, this mean value for energy intake would have been inadequate to match the peak energy expended during the most physically demanding 24 hours of the race.

Assessment of flywheel energy storage for spacecraft power systems

NASA Technical Reports Server (NTRS)

Rodriguez, G. E.; Studer, P. A.; Baer, D. A.

1983-01-01

The feasibility of inertial energy storage in a spacecraft power system is evaluated on the basis of a conceptual integrated design that encompasses a composite rotor, magnetic suspension, and a permanent magnet (PM) motor/generator for a 3-kW orbital average payload at a bus distribution voltage of 250 volts dc. The conceptual design, which evolved at the Goddard Space Flight Center (GSFC), is referred to as a Mechanical Capacitor. The baseline power system configuration selected is a series system employing peak-power-tracking for a Low Earth-Orbiting application. Power processing, required in the motor/generator, provides a potential alternative configurations that can only be achieved in systems with electrochemical energy storage by the addition of power processing components. One such alternative configuration provides for peak-power-tracking of the solar array and still maintains a regulated bus, without the expense of additional power processing components. Precise speed control of the two counterrotating wheels is required to reduce interaction with the attitude control system (ACS) or alternatively, used to perform attitude control functions. Critical technologies identified are those pertaining to the energy storage element and are prioritized as composite wheel development, magnetic suspension, motor/generator, containment, and momentum control. Comparison with a 3-kW, 250-Vdc power system using either NiCd or NiH2 for energy storage results in a system in which inertial energy storage offers potential advantages in lifetime, operating temperature, voltage regulation, energy density, charge control, and overall system weight reduction.

Lower Amplitude of the Hoffmann Reflex in Women With Patellofemoral Pain: Thinking Beyond Proximal, Local, and Distal Factors.

PubMed

de Oliveira Silva, Danilo; Magalhães, Fernando Henrique; Faria, Nathálie Clara; Pazzinatto, Marcella Ferraz; Ferrari, Deisi; Pappas, Evangelos; de Azevedo, Fábio Mícolis

2016-07-01

To investigate whether vastus medialis (VM) Hoffmann reflexes (H-reflexes) differ on the basis of the presence or absence of patellofemoral pain (PFP) and to assess the capability of VM H-reflex measurements in accurately discriminating between women with and without PFP. Cross-sectional study. Laboratory of biomechanics and motor control. Women (N=30) aged 18 to 35 years were recruited, consisting of 2 groups: women with PFP (n=15) and asymptomatic controls (n=15). Not applicable. Maximum evoked responses were obtained by electrical stimulation applied to the femoral nerve, and peak-to-peak amplitudes of maximal Hoffmann reflex (Hmax) and maximal motor wave (Mmax) ratios were calculated. Independent samples t tests were performed to identify differences between groups, and a receiver operating characteristic curve was constructed to assess the discriminatory capability of VM H-reflex measurements. VM Hmax/Mmax ratios were significantly lower in participants with PFP than in pain-free participants (P=.007). In addition, the VM Hmax/Mmax ratios presented large and balanced discriminatory capability values (sensitivity, 73%; specificity, 67%). This study is the first to show that VM H-reflexes are lower in women with PFP than in asymptomatic controls. Therefore, increasing the excitation of the spinal cord in PFP participants may be essential to maintaining the gains acquired during the rehabilitation programs. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Blast overpressure in rats: recreating a battlefield injury in the laboratory.

PubMed

Long, Joseph B; Bentley, Timothy L; Wessner, Keith A; Cerone, Carolyn; Sweeney, Sheena; Bauman, Richard A

2009-06-01

Blast injury to the brain is the predominant cause of neurotrauma in current military conflicts, and its etiology is largely undefined. Using a compression-driven shock tube to simulate blast effects, we assessed the physiological, neuropathological, and neurobehavioral consequences of airblast exposure, and also evaluated the effect of a Kevlar protective vest on acute mortality in rats and on the occurrence of traumatic brain injury (TBI) in those that survived. This approach provides survivable blast conditions under which TBI can be studied. Striking neuropathological changes were caused by both 126- and 147-kPa airblast exposures. The Kevlar vest, which encased the thorax and part of the abdomen, greatly reduced airblast mortality, and also ameliorated the widespread fiber degeneration that was prominent in brains of rats not protected by a vest during exposure to a 126-kPa airblast. This finding points to a significant contribution of the systemic effects of airblast to its brain injury pathophysiology. Airblast of this intensity also disrupted neurologic and neurobehavioral performance (e.g., beam walking and spatial navigation acquisition in the Morris water maze). When immediately followed by hemorrhagic hypotension, with MAP maintained at 30 mm Hg, airblast disrupted cardiocompensatory resilience, as reflected by reduced peak shed blood volume, time to peak shed blood volume, and time to death. These findings demonstrate that shock tube-generated airblast can cause TBI in rats, in part through systemic mediation, and that the resulting brain injury significantly impacts acute cardiovascular homeostatic mechanisms as well as neurobehavioral function.

Peak-Seeking Optimization of Trim for Reduced Fuel Consumption: Architecture and Performance Predictions

NASA Technical Reports Server (NTRS)

Schaefer, Jacob; Brown, Nelson

2013-01-01

A peak-seeking control approach for real-time trim configuration optimization for reduced fuel consumption has been developed by researchers at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center to address the goals of the NASA Environmentally Responsible Aviation project to reduce fuel burn and emissions. The peak-seeking control approach is based on a steepest-descent algorithm using a time-varying Kalman filter to estimate the gradient of a performance function of fuel flow versus control surface positions. In real-time operation, deflections of symmetric ailerons, trailing-edge flaps, and leading-edge flaps of an FA-18 airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) are controlled for optimization of fuel flow. This presentation presents the design and integration of this peak-seeking controller on a modified NASA FA-18 airplane with research flight control computers. A research flight was performed to collect data to build a realistic model of the performance function and characterize measurement noise. This model was then implemented into a nonlinear six-degree-of-freedom FA-18 simulation along with the peak-seeking control algorithm. With the goal of eventual flight tests, the algorithm was first evaluated in the improved simulation environment. Results from the simulation predict good convergence on minimum fuel flow with a 2.5-percent reduction in fuel flow relative to the baseline trim of the aircraft.

Peak-Seeking Optimization of Trim for Reduced Fuel Consumption: Architecture and Performance Predictions

NASA Technical Reports Server (NTRS)

Schaefer, Jacob; Brown, Nelson A.

2013-01-01

A peak-seeking control approach for real-time trim configuration optimization for reduced fuel consumption has been developed by researchers at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center to address the goals of the NASA Environmentally Responsible Aviation project to reduce fuel burn and emissions. The peak-seeking control approach is based on a steepest-descent algorithm using a time-varying Kalman filter to estimate the gradient of a performance function of fuel flow versus control surface positions. In real-time operation, deflections of symmetric ailerons, trailing-edge flaps, and leading-edge flaps of an F/A-18 airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) are controlled for optimization of fuel flow. This paper presents the design and integration of this peak-seeking controller on a modified NASA F/A-18 airplane with research flight control computers. A research flight was performed to collect data to build a realistic model of the performance function and characterize measurement noise. This model was then implemented into a nonlinear six-degree-of-freedom F/A-18 simulation along with the peak-seeking control algorithm. With the goal of eventual flight tests, the algorithm was first evaluated in the improved simulation environment. Results from the simulation predict good convergence on minimum fuel flow with a 2.5-percent reduction in fuel flow relative to the baseline trim of the aircraft.

Supercompensation Kinetics of Physical Qualities During a Taper in Team-Sport Athletes.

PubMed

Marrier, Bruno; Robineau, Julien; Piscione, Julien; Lacome, Mathieu; Peeters, Alexis; Hausswirth, Christophe; Morin, Jean-Benoît; Le Meur, Yann

2017-10-01

Peaking for major competition is considered critical for maximizing team-sport performance. However, there is little scientific information available to guide coaches in prescribing efficient tapering strategies for team-sport players. To monitor the changes in physical performance in elite team-sport players during a 3-wk taper after a preseason training camp. Ten male international rugby sevens players were tested before (Pre) and after (Post) a 4-wk preseason training camp focusing on high-intensity training and strength training with moderate loads and once each week during a subsequent 3-wk taper. During each testing session, midthigh-pull maximal strength, sprint-acceleration mechanical outputs, and performance, as well as repeated-sprint ability (RSA), were assessed. At Post, no single peak performance was observed for maximal lower-limb force output and sprint performance, while RSA peaked for only 1 athlete. During the taper, 30-m-sprint time decreased almost certainly (-3.1% ± 0.9%, large), while maximal lower-limb strength and RSA, respectively, improved very likely (+7.7% ± 5.3%, small) and almost certainly (+9.0% ± 2.6%, moderate). Of the peak performances, 70%, 80%, and 80% occurred within the first 2 wk of taper for RSA, maximal force output, and sprint performance, respectively. These results show the sensitivity of physical qualities to tapering in rugby sevens players and suggest that an ~1- to 2-wk tapering time frame appears optimal to maximize the overall physical-performance response.

Systematic Self-Regulation of the Neural System Essential for Peak Performance and Wellbeing.

ERIC Educational Resources Information Center

Cassel, Russell N.

1985-01-01

Balance and harmony within one's neural system is dynamic and changing, and restoring that balance is essential for peak performance. With a minimum amount of training individuals are able to restore this delicate balance and thereby enhance their own wellbeing. Autogenic feedback training has been demonstrated to be an effective means for…

Aerodynamic performance of a 1.25-pressure-ratio axial-flow fan stage

NASA Technical Reports Server (NTRS)

Moore, R. D.; Steinke, R. J.

1974-01-01

Aerodynamic design parameters and overall and blade-element performances of a 1.25-pressure-ratio fan stage are reported. Detailed radial surveys were made over the stable operating flow range at rotative speeds from 70 to 120 percent of design speed. At design speed, the measured stage peak efficiency of 0.872 occurred at a weight flow of 34.92 kilograms per second and a pressure ratio of 1.242. Stage stall margin is about 20 percent based on the peak efficiency and stall conditions. The overall peak efficiency for the rotor was 0.911. The overall stage performance showed no significant change when the stators were positioned at 1, 2, or 4 chords downstream of the rotor.

Digesting or swimming? Integration of the postprandial metabolism, behavior and locomotion in a frequently foraging fish.

PubMed

Nie, Li-Juan; Cao, Zhen-Dong; Fu, Shi-Jian

2017-02-01

Fish that are active foragers usually perform routine activities while digesting their food; thus, their postprandial swimming capacity and related behavior adjustments might be ecologically important. To test whether digestion affect swimming performance and the relationships of digestion with metabolism and behavior in an active forager, we investigated the postprandial metabolic response, spontaneous swimming activities, critical swimming speed (Ucrit), and fast-start escape performance of both fasted and digesting (3h after feeding to satiation) juvenile rose bitterling (Rhodeus ocellatus). Feeding to satiation elicited a 50% increase in the oxygen consumption rate, which peaked at 3h after feeding and returned to the prefeeding state after another 3h. However, approximately 50% and 90% of individuals resumed feeding behavior at 2 and 3h postfeeding, respectively, although the meal size varied substantially. Digestion showed no effect on either steady swimming performance as suggested by the Ucrit or unsteady swimming performance indicated by the maximum linear velocity in fast-start escape movement. However, digesting fish showed more spontaneous activity as indicated by the longer total distance traveled, mainly through an increased percentage of time spent moving (PTM). A further analysis found that fasting individuals with high swimming speed were more inclined to increase their PTM during digestive processes. The present study suggests that as an active forager With a small meal size and hence limited postprandial physiological and morphological changes, the swimming performance of rose bitterling is maintained during digestion, which might be crucial for its active foraging mode and anti-predation strategy. Copyright © 2016 Elsevier Inc. All rights reserved.

Using the HDI camera with Tohono O’odham Tribal Community College Students

NASA Astrophysics Data System (ADS)

Garmany, Catharine D.

2017-01-01

Tohono O’odham Community College is a small two-year tribal college, located at the foot of I'oligam Du'ag, also known as Kitt Peak. In recognition and appreciation of Kitt Peak National Observatory’s location on the Tohono O’odham reservation, NOAO has worked with the college to offer an introduction astronomy class when requested. The class has been taught by NOAO scientific staff and post docs, and the lab component of this 4-credit class has been carried out at Kitt Peak. With support from the WIYN0.9-m Consortium, students have been able to observe on the 0.9m telescope. Most recently they have used the HDI camera for an evening, which has been a highlight of the class that students always note in their final evaluation. I will describe challenges and rewards in developing and maintaining this class, including identifying post docs and graduate students who are able to teach it. However, we feel the challenges are worth it: this may be the only formal astronomy class offered at a tribal college.

Endocrine basis of the reproductive pattern of the Gentoo penguin (Pygoscelis papua): winter breeding and extended laying period in northern populations.

PubMed

Mauget, R; Garcia, V; Jouventin, P

1995-05-01

Changes in plasma LH, prolactin, testosterone, estradiol, and progesterone were investigated throughout moult and reproduction in free-living male and female Gentoo penguins (Pygoscelis papua) at Crozet Island (46 degrees S, 51 degrees E), where this species is able to relay after a reproductive failure. In both sexes, LH, prolactin, and steroid hormones, remained at basal levels during the moult. LH level was highest at the time of arrival at the colony for breeding and, although it decreased after courtship, it did not drop at basal value by incubation and first chick brooding period. Prolactin peaked for both chick brooding periods; replacement clutch was associated with an increased secretion of LH, whereas high prolactin levels were maintained. Testosterone, in male, and estradiol, in female, peaked during courtship I and chick brooding II; progesterone, in female, peaked during courtship I and II. These hormonal patterns are consistent with those observed in passerine species which are also able to relay after a reproductive failure. Winter breeding observed at Crozet Island might reflect the extreme adaptive capacity of Gentoo penguin species.

A comparison of peak power in the shoulder press and shoulder throw.

PubMed

Dalziel, W M; Neal, R J; Watts, M C

2002-09-01

The ability to generate peak power is central for performance in many sports. Currently two distinct resistance training methods are used to develop peak power, the heavy weight/slow velocity and light weight/fast velocity regimes. When using the light weight/fast velocity power training method it was proposed that peak power would be greater in a shoulder throw exercise compared with a normal shoulder press. Nine males performed three lifts in the shoulder press and shoulder throw at 30% and 40% of their one repetition maximum (1RM). These lifts were performed identically, except for the release of the bar in the throw condition. A potentiometer attached to the bar measured displacement and duration of the lifts. The time of bar release in the shoulder throw was determined with a pressure switch. ANOVA was used to examine statistically significant differences where the level of acceptance was set at p < 0.05. Peak power was found to be significantly greater in the shoulder throw at 30% of 1 RM condition [F, (1, 23) = 2.325 p < 0.051 and at 40% of 1 RM [F, (1, 23) = 2.905 p < 0.05] compared to values recorded for the respective shoulder presses. Peak power was also greater in the 30% of 1 RM shoulder throw (510 +/- 103W) than in the 40% of 1 RM shoulder press (471 +/- 96W). Peak power was produced significantly later in the shoulder throw versus the shoulder press. This differing power reflected a greater bar velocity of the shoulder throw at both assigned weights compared with the shoulder press.

Jumping and hopping in elite and amateur orienteering athletes and correlations to sprinting and running.

PubMed

Hébert-Losier, Kim; Jensen, Kurt; Holmberg, Hans-Christer

2014-11-01

Jumping and hopping are used to measure lower-body muscle power, stiffness, and stretch-shortening-cycle utilization in sports, with several studies reporting correlations between such measures and sprinting and/or running abilities in athletes. Neither jumping and hopping nor correlations with sprinting and/or running have been examined in orienteering athletes. The authors investigated squat jump (SJ), countermovement jump (CMJ), standing long jump (SLJ), and hopping performed by 8 elite and 8 amateur male foot-orienteering athletes (29 ± 7 y, 183 ± 5 cm, 73 ± 7 kg) and possible correlations to road, path, and forest running and sprinting performance, as well as running economy, velocity at anaerobic threshold, and peak oxygen uptake (VO(2peak)) from treadmill assessments. During SJs and CMJs, elites demonstrated superior relative peak forces, times to peak force, and prestretch augmentation, albeit lower SJ heights and peak powers. Between-groups differences were unclear for CMJ heights, hopping stiffness, and most SLJ parameters. Large pairwise correlations were observed between relative peak and time to peak forces and sprinting velocities; time to peak forces and running velocities; and prestretch augmentation and forest-running velocities. Prestretch augmentation and time to peak forces were moderately correlated to VO(2peak). Correlations between running economy and jumping or hopping were small or trivial. Overall, the elites exhibited superior stretch-shortening-cycle utilization and rapid generation of high relative maximal forces, especially vertically. These functional measures were more closely related to sprinting and/or running abilities, indicating benefits of lower-body training in orienteering.

Genetic and Dynamic Analysis of Murine Peak Bone Density

DTIC Science & Technology

1998-10-01

number of diseases including Waardenburg syndrome (18, 19) and retinitis pigmentosa (20). Substantial computerized genetic data bases maintained at...411, 1992. 14. Foy, C., Newton, V., Wellesley, D., Harris, R., and Read, A. P. Assignment of the locus for Waardenburg syndrome type 1 to human...Balling, R., Gruss, P., and Strachan, T. Waardenburg’s syndrome patients have mutations in the human homologue of the Pax-3 paired box gene, Nature

Can You Hear That Peak? Utilization of Auditory and Visual Feedback at Peak Limb Velocity.

PubMed

Loria, Tristan; de Grosbois, John; Tremblay, Luc

2016-09-01

At rest, the central nervous system combines and integrates multisensory cues to yield an optimal percept. When engaging in action, the relative weighing of sensory modalities has been shown to be altered. Because the timing of peak velocity is the critical moment in some goal-directed movements (e.g., overarm throwing), the current study sought to test whether visual and auditory cues are optimally integrated at that specific kinematic marker when it is the critical part of the trajectory. Participants performed an upper-limb movement in which they were required to reach their peak limb velocity when the right index finger intersected a virtual target (i.e., a flinging movement). Brief auditory, visual, or audiovisual feedback (i.e., 20 ms in duration) was provided to participants at peak limb velocity. Performance was assessed primarily through the resultant position of peak limb velocity and the variability of that position. Relative to when no feedback was provided, auditory feedback significantly reduced the resultant endpoint variability of the finger position at peak limb velocity. However, no such reductions were found for the visual or audiovisual feedback conditions. Further, providing both auditory and visual cues concurrently also failed to yield the theoretically predicted improvements in endpoint variability. Overall, the central nervous system can make significant use of an auditory cue but may not optimally integrate a visual and auditory cue at peak limb velocity, when peak velocity is the critical part of the trajectory.

Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training

PubMed Central

Stöggl, Thomas; Sperlich, Billy

2014-01-01

Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT), “threshold-training” (THR), high-intensity interval training (HIIT) and a combination of these aforementioned concepts known as polarized training (POL). The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes, and cross-country skiers (peak oxygen uptake: (VO2peak): 62.6 ± 7.1 mL·min−1·kg−1) were randomly assigned to one of four groups performing over 9 weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml·min·kg−1 or 11.7%, P < 0.001), time to exhaustion during the ramp protocol (+17.4%, P < 0.001) and peak velocity/power (+5.1%, P < 0.01). Velocity/power at 4 mmol·L−1 increased after POL (+8.1%, P < 0.01) and HIIT (+5.6%, P < 0.05). No differences in pre- to post-changes of work economy were found between the groups. Body mass was reduced by 3.7% (P < 0.001) following HIIT, with no changes in the other groups. With the exception of slight improvements in work economy in THR, both HVT and THR had no further effects on measured variables of endurance performance (P > 0.05). Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables. PMID:24550842

An exploration of the influence of diagonal dissociation and moderate changes in speed on locomotor parameters in trotting horses.

PubMed

Hobbs, Sarah Jane; Bertram, John E A; Clayton, Hilary M

2016-01-01

Background. Although the trot is described as a diagonal gait, contacts of the diagonal pairs of hooves are not usually perfectly synchronized. Although subtle, the timing dissociation between contacts of each diagonal pair could have consequences on gait dynamics and provide insight into the functional strategies employed. This study explores the mechanical effects of different diagonal dissociation patterns when speed was matched between individuals and how these effects link to moderate, natural changes in trotting speed. We anticipate that hind-first diagonal dissociation at contact increases with speed, diagonal dissociation at contact can reduce collision-based energy losses and predominant dissociation patterns will be evident within individuals. Methods. The study was performed in two parts: in the first 17 horses performed speed-matched trotting trials and in the second, five horses each performed 10 trotting trials that represented a range of individually preferred speeds. Standard motion capture provided kinematic data that were synchronized with ground reaction force (GRF) data from a series of force plates. The data were analyzed further to determine temporal, speed, GRF, postural, mass distribution, moment, and collision dynamics parameters. Results. Fore-first, synchronous, and hind-first dissociations were found in horses trotting at (3.3 m/s ± 10%). In these speed-matched trials, mean centre of pressure (COP) cranio-caudal location differed significantly between the three dissociation categories. The COP moved systematically and significantly (P = .001) from being more caudally located in hind-first dissociation (mean location = 0.41 ± 0.04) through synchronous (0.36 ± 0.02) to a more cranial location in fore-first dissociation (0.32 ± 0.02). Dissociation patterns were found to influence function, posture, and balance parameters. Over a moderate speed range, peak vertical forelimb GRF had a strong relationship with dissociation time (R = .594; P < .01) and speed (R = .789; P < .01), but peak vertical hindlimb GRF did not have a significant relationship with dissociation time (R = .085; P > 0.05) or speed (R = .223; P = .023). Discussion. The results indicate that at moderate speeds individual horses use dissociation patterns that allow them to maintain trunk pitch stability through management of the cranio-caudal location of the COP. During the hoof-ground collisions, reduced mechanical energy losses were found in hind-first dissociations compared to fully synchronous contacts. As speed increased, only forelimb vertical peak force increased so dissociations tended towards hind-first, which shifted the net COP caudally and balanced trunk pitching moments.

Temporal evolution modeling of hydraulic and water quality performance of permeable pavements

NASA Astrophysics Data System (ADS)

Huang, Jian; He, Jianxun; Valeo, Caterina; Chu, Angus

2016-02-01

A mathematical model for predicting hydraulic and water quality performance in both the short- and long-term is proposed based on field measurements for three types of permeable pavements: porous asphalt (PA), porous concrete (PC), and permeable inter-locking concrete pavers (PICP). The model was applied to three field-scale test sites in Calgary, Alberta, Canada. The model performance was assessed in terms of hydraulic parameters including time to peak, peak flow and water balance and a water quality variable (the removal rate of total suspended solids). A total of 20 simulated storm events were used for model calibration and verification processes. The proposed model can simulate the outflow hydrographs with a coefficient of determination (R2) ranging from 0.762 to 0.907, and normalized root-mean-square deviation (NRMSD) ranging from 13.78% to 17.83%. Comparison of the time to peak flow, peak flow, runoff volume and TSS removal rates between the measured and modeled values in model verification phase had a maximum difference of 11%. The results demonstrate that the proposed model is capable of capturing the temporal dynamics of the pavement performance. Therefore, the model has great potential as a practical modeling tool for permeable pavement design and performance assessment.

The level and nature of autistic intelligence II: what about Asperger syndrome?

PubMed

Soulières, Isabelle; Dawson, Michelle; Gernsbacher, Morton Ann; Mottron, Laurent

2011-01-01

A distinctively uneven profile of intelligence is a feature of the autistic spectrum. Within the spectrum, Asperger individuals differ from autistics in their early speech development and in being less likely to be characterized by visuospatial peaks. While different specific strengths characterize different autistic spectrum subgroups, all such peaks of ability have been interpreted as deficits: isolated, aberrant, and irreconcilable with real human intelligence. This view has recently been challenged by findings of autistic strengths in performance on Raven's Progressive Matrices (RPM), an important marker of general and fluid intelligence. We investigated whether these findings extend to Asperger syndrome, an autistic spectrum subgroup characterized by verbal peaks of ability, and whether the cognitive mechanisms underlying autistic and Asperger RPM performance differ. Thirty-two Asperger adults displayed a significant advantage on RPM over Wechsler Full-Scale and Performance scores relative to their typical controls, while in 25 Asperger children an RPM advantage was found over Wechsler Performance scores only. As previously found with autistics, Asperger children and adults achieved RPM scores at a level reflecting their Wechsler peaks of ability. Therefore, strengths in RPM performance span the autistic spectrum and imply a common mechanism advantageously applied to different facets of cognition. Autistic spectrum intelligence is atypical, but also genuine, general, and underestimated.

The Level and Nature of Autistic Intelligence II: What about Asperger Syndrome?

PubMed Central

Soulières, Isabelle; Dawson, Michelle; Gernsbacher, Morton Ann; Mottron, Laurent

2011-01-01

A distinctively uneven profile of intelligence is a feature of the autistic spectrum. Within the spectrum, Asperger individuals differ from autistics in their early speech development and in being less likely to be characterized by visuospatial peaks. While different specific strengths characterize different autistic spectrum subgroups, all such peaks of ability have been interpreted as deficits: isolated, aberrant, and irreconcilable with real human intelligence. This view has recently been challenged by findings of autistic strengths in performance on Raven's Progressive Matrices (RPM), an important marker of general and fluid intelligence. We investigated whether these findings extend to Asperger syndrome, an autistic spectrum subgroup characterized by verbal peaks of ability, and whether the cognitive mechanisms underlying autistic and Asperger RPM performance differ. Thirty-two Asperger adults displayed a significant advantage on RPM over Wechsler Full-Scale and Performance scores relative to their typical controls, while in 25 Asperger children an RPM advantage was found over Wechsler Performance scores only. As previously found with autistics, Asperger children and adults achieved RPM scores at a level reflecting their Wechsler peaks of ability. Therefore, strengths in RPM performance span the autistic spectrum and imply a common mechanism advantageously applied to different facets of cognition. Autistic spectrum intelligence is atypical, but also genuine, general, and underestimated. PMID:21991394

Cognitive Mechanisms, Specificity and Neural Underpinnings of Visuospatial Peaks in Autism

ERIC Educational Resources Information Center

Caron, M.-J.; Mottron, L.; Berthiaume, C.; Dawson, M.

2006-01-01

In order to explain the cognitive and cerebral mechanisms responsible for the visuospatial peak in autism, and to document its specificity to this condition, a group of eight high-functioning individuals with autism and a visuospatial peak (HFA-P) performed a modified block-design task (BDT; subtest from Wechsler scales) at various levels of…

Dark soliton synthesis using an optical pulse synthesizer and transmission through a normal-dispersion optical fiber.

PubMed

Kashiwagi, Ken; Mozawa, Kiyonobu; Tanaka, Yosuke; Kurokawa, Takashi

2013-12-16

We precisely generate dark solitons using an optical pulse synthesizer (OPS) at a repetition rate of 25 GHz and experimentally investigate soliton transmission through a normal-dispersion fiber. Because of their particular waveform, there are not many experimental studies. The OPS provides frequency-domain line-by-line modulation and produces arbitrary pulse waveforms. The soliton waveform has an intensity contrast greater than 20 dB. At certain input peak power, the pulse exhibits soliton transmission and maintains its initial waveform. The power agrees with soliton transmission theory. We confirm that the π phase shift at the center of the dark soliton is maintained after transmission through the fiber. We also investigate the influence of stimulated Brillouin scattering for long-distance transmission.

Switchable multiwavelength erbium-doped photonic crystal fiber ring laser based on a length of polarization-maintaining photonic crystal fiber

NASA Astrophysics Data System (ADS)

Cheng, Jianqun; Ruan, Shuangchen

2011-11-01

A switchable multi-wavelength Erbium-doped photonic crystal fiber (ED-PCF) ring laser based on a length of polarization-maintaining photonic crystal fiber(PM-PCF) is presented and demonstrated experimentally. A segment of ED-PCF is used as linear gain medium in the resonant cavity. Due to the polarization hole burning (PHB) caused by the PM-PCF and a polarization controller (PC), the laser can operate in stable dual- or triple- wavelength modes at room temperature. The optical signal-to-noise ratio (OSNR) of the laser without any wavelength-selective components is greater than 30 dB. The amplitude variations of lasing peaks in ten minutes are less than 0.26dB for two different operating modes.

Switchable multiwavelength erbium-doped photonic crystal fiber ring laser based on a length of polarization-maintaining photonic crystal fiber

NASA Astrophysics Data System (ADS)

Cheng, Jianqun; Ruan, Shuangchen

2012-03-01

A switchable multi-wavelength Erbium-doped photonic crystal fiber (ED-PCF) ring laser based on a length of polarization-maintaining photonic crystal fiber(PM-PCF) is presented and demonstrated experimentally. A segment of ED-PCF is used as linear gain medium in the resonant cavity. Due to the polarization hole burning (PHB) caused by the PM-PCF and a polarization controller (PC), the laser can operate in stable dual- or triple- wavelength modes at room temperature. The optical signal-to-noise ratio (OSNR) of the laser without any wavelength-selective components is greater than 30 dB. The amplitude variations of lasing peaks in ten minutes are less than 0.26dB for two different operating modes.

Transverse load sensor based on Mach-Zehnder interferometer constructed by a bowknot type taper

NASA Astrophysics Data System (ADS)

Lou, Weimin; Shentu, Fengying; Wang, Youqing; Shen, Changyu; Dong, Xinyong

2018-01-01

A transverse load fiber sensor based on Mach-Zehnder interferometer constructed by a Bowknot-type taper between a single mode fiber (SMF) and a polarization maintaining fiber (PMF) was proposed. Due to the polarization maintaining fiber's birefringence, intensities of the two peaks which are corresponding to the fast and slow axis modes changed with the transverse load applied on the PMF. The experimental results showed that the structure with a 2 cm-long PMF has the sensitivities of 104.52 and -102.94 dB/(N/mm) for the fast and slow axis spectral dip wavelengths of 1485 and 1545 nm in the interference pattern, respectively, which are almost 7 times higher than that of the current similar existing transverse load sensor.

Mobile phase additives for enhancing the chromatographic performance of astaxanthin on nonendcapped polymeric C30-bonded stationary phases.

PubMed

Kaiser, Philipp; Surmann, Peter; Fuhrmann, Herbert

2009-01-01

Astaxanthin shows peak deformation and reduced peak area response when eluted with methanol and methyl tert-butyl ether on nonendcapped polymeric C30-bonded HPLC phases. The present study tested different column manufacturers, column batches, and ten mobile phase additives including acids, bases, buffers, complexing and antioxidant agents for improvement of peak shape and peak area response. Concerning chromatographic benefits and feasibility, ammonium acetate was found to be the best additive followed by triethylamine for all columns tested. Variation of the mobile phase pH equivalent and the column temperature showed no synergistic effects on peak shape and peak area response. Results indicate that peak tailing and variation of peak area response are due to different on-column effects. Possible mechanisms of the observed phenomenon will be discussed.

Performance evaluation of non-targeted peak-based cross-sample analysis for comprehensive two-dimensional gas chromatography-mass spectrometry data and application to processed hazelnut profiling.

PubMed

Kiefl, Johannes; Cordero, Chiara; Nicolotti, Luca; Schieberle, Peter; Reichenbach, Stephen E; Bicchi, Carlo

2012-06-22

The continuous interest in non-targeted profiling induced the development of tools for automated cross-sample analysis. Such tools were found to be selective or not comprehensive thus delivering a biased view on the qualitative/quantitative peak distribution across 2D sample chromatograms. Therefore, the performance of non-targeted approaches needs to be critically evaluated. This study focused on the development of a validation procedure for non-targeted, peak-based, GC×GC-MS data profiling. The procedure introduced performance parameters such as specificity, precision, accuracy, and uncertainty for a profiling method known as Comprehensive Template Matching. The performance was assessed by applying a three-week validation protocol based on CITAC/EURACHEM guidelines. Optimized ¹D and ²D retention times search windows, MS match factor threshold, detection threshold, and template threshold were evolved from two training sets by a semi-automated learning process. The effectiveness of proposed settings to consistently match 2D peak patterns was established by evaluating the rate of mismatched peaks and was expressed in terms of results accuracy. The study utilized 23 different 2D peak patterns providing the chemical fingerprints of raw and roasted hazelnuts (Corylus avellana L.) from different geographical origins, of diverse varieties and different roasting degrees. The validation results show that non-targeted peak-based profiling can be reliable with error rates lower than 10% independent of the degree of analytical variance. The optimized Comprehensive Template Matching procedure was employed to study hazelnut roasting profiles and in particular to find marker compounds strongly dependent on the thermal treatment, and to establish the correlation of potential marker compounds to geographical origin and variety/cultivar and finally to reveal the characteristic release of aroma active compounds. Copyright © 2012 Elsevier B.V. All rights reserved.

The Andersen aerobic fitness test: New peak oxygen consumption prediction equations in 10 and 16-year olds.

PubMed

Aadland, E; Andersen, L B; Lerum, Ø; Resaland, G K

2018-03-01

Measurement of aerobic fitness by determining peak oxygen consumption (VO 2peak ) is often not feasible in children and adolescents, thus field tests such as the Andersen test are required in many settings, for example in most school-based studies. This study provides cross-validated prediction equations for VO 2peak based on the Andersen test in 10 and 16-year-old children. We included 235 children (n = 113 10-year olds and 122 16-year olds) who performed the Andersen test and a progressive treadmill test to exhaustion to determine VO 2peak . Joint and sex-specific prediction equations were derived and tested in 20 random samples. Performance in terms of systematic (bias) and random error (limits of agreement) was evaluated by means of Bland-Altman plots. Bias varied from -4.28 to 5.25 mL/kg/min across testing datasets, sex, and the 2 age groups. Sex-specific equations (mean bias -0.42 to 0.16 mL/kg/min) performed somewhat better than joint equations (-1.07 to 0.84 mL/kg/min). Limits of agreement were substantial across all datasets, sex, and both age groups, but were slightly lower in 16-year olds (5.84-13.29 mL/kg/min) compared to 10-year olds (9.60-15.15 mL/kg/min). We suggest the presented equations can be used to predict VO 2peak from the Andersen test performance in children and adolescents on a group level. Although the Andersen test appears to be a good measure of aerobic fitness, researchers should interpret cross-sectional individual-level predictions of VO 2peak with caution due to large random measurement errors. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Normal-Gamma-Bernoulli Peak Detection for Analysis of Comprehensive Two-Dimensional Gas Chromatography Mass Spectrometry Data.

PubMed

Kim, Seongho; Jang, Hyejeong; Koo, Imhoi; Lee, Joohyoung; Zhang, Xiang

2017-01-01

Compared to other analytical platforms, comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS) has much increased separation power for analysis of complex samples and thus is increasingly used in metabolomics for biomarker discovery. However, accurate peak detection remains a bottleneck for wide applications of GC×GC-MS. Therefore, the normal-exponential-Bernoulli (NEB) model is generalized by gamma distribution and a new peak detection algorithm using the normal-gamma-Bernoulli (NGB) model is developed. Unlike the NEB model, the NGB model has no closed-form analytical solution, hampering its practical use in peak detection. To circumvent this difficulty, three numerical approaches, which are fast Fourier transform (FFT), the first-order and the second-order delta methods (D1 and D2), are introduced. The applications to simulated data and two real GC×GC-MS data sets show that the NGB-D1 method performs the best in terms of both computational expense and peak detection performance.

Low-complexity R-peak detection for ambulatory fetal monitoring.

PubMed

Rooijakkers, Michael J; Rabotti, Chiara; Oei, S Guid; Mischi, Massimo

2012-07-01

Non-invasive fetal health monitoring during pregnancy is becoming increasingly important because of the increasing number of high-risk pregnancies. Despite recent advances in signal-processing technology, which have enabled fetal monitoring during pregnancy using abdominal electrocardiogram (ECG) recordings, ubiquitous fetal health monitoring is still unfeasible due to the computational complexity of noise-robust solutions. In this paper, an ECG R-peak detection algorithm for ambulatory R-peak detection is proposed, as part of a fetal ECG detection algorithm. The proposed algorithm is optimized to reduce computational complexity, without reducing the R-peak detection performance compared to the existing R-peak detection schemes. Validation of the algorithm is performed on three manually annotated datasets. With a detection error rate of 0.23%, 1.32% and 9.42% on the MIT/BIH Arrhythmia and in-house maternal and fetal databases, respectively, the detection rate of the proposed algorithm is comparable to the best state-of-the-art algorithms, at a reduced computational complexity.

System Mass Variation and Entropy Generation in 100k We Closed-Brayton-Cycle Space Power Systems

NASA Technical Reports Server (NTRS)

Barrett, Michael J.; Reid, Bryan M.

2004-01-01

State-of-the-art closed-Brayton-cycle (CBC) space power systems were modeled to study performance trends in a trade space characteristic of interplanetary orbiters. For working-fluid molar masses of 48.6, 39.9, and 11.9 kg/kmol, peak system pressures of 1.38 and 3.0 MPa and compressor pressure ratios ranging from 1.6 to 2.4, total system masses were estimated. System mass increased as peak operating pressure increased for all compressor pressure ratios and molar mass values examined. Minimum mass point comparison between 72 percent He at 1.38 MPa peak and 94 percent He at 3.0 MPa peak showed an increase in system mass of 14 percent. Converter flow loop entropy generation rates were calculated for 1.38 and 3.0 MPa peak pressure cases. Physical system behavior was approximated using a pedigreed NASA Glenn modeling code, Closed Cycle Engine Program (CCEP), which included realistic performance prediction for heat exchangers, radiators and turbomachinery.

System Mass Variation and Entropy Generation in 100-kWe Closed-Brayton-Cycle Space Power Systems

NASA Technical Reports Server (NTRS)

Barrett, Michael J.; Reid, Bryan M.

2004-01-01

State-of-the-art closed-Brayton-cycle (CBC) space power systems were modeled to study performance trends in a trade space characteristic of interplanetary orbiters. For working-fluid molar masses of 48.6, 39.9, and 11.9 kg/kmol, peak system pressures of 1.38 and 3.0 MPa and compressor pressure ratios ranging from 1.6 to 2.4, total system masses were estimated. System mass increased as peak operating pressure increased for all compressor pressure ratios and molar mass values examined. Minimum mass point comparison between 72 percent He at 1.38 MPa peak and 94 percent He at 3.0 MPa peak showed an increase in system mass of 14 percent. Converter flow loop entropy generation rates were calculated for 1.38 and 3.0 MPa peak pressure cases. Physical system behavior was approximated using a pedigreed NASA Glenn modeling code, Closed Cycle Engine Program (CCEP), which included realistic performance prediction for heat exchangers, radiators and turbomachinery.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stinnett, Jacob; Sullivan, Clair J.; Xiong, Hao

Low-resolution isotope identifiers are widely deployed for nuclear security purposes, but these detectors currently demonstrate problems in making correct identifications in many typical usage scenarios. While there are many hardware alternatives and improvements that can be made, performance on existing low resolution isotope identifiers should be able to be improved by developing new identification algorithms. We have developed a wavelet-based peak extraction algorithm and an implementation of a Bayesian classifier for automated peak-based identification. The peak extraction algorithm has been extended to compute uncertainties in the peak area calculations. To build empirical joint probability distributions of the peak areas andmore » uncertainties, a large set of spectra were simulated in MCNP6 and processed with the wavelet-based feature extraction algorithm. Kernel density estimation was then used to create a new component of the likelihood function in the Bayesian classifier. Furthermore, identification performance is demonstrated on a variety of real low-resolution spectra, including Category I quantities of special nuclear material.« less

Phenological Impacts of Hurricane Katrina (2005) and Gustav (2008) on Louisiana Coastal Marshes

NASA Astrophysics Data System (ADS)

Mo, Y.; Kearney, M.; Riter, A.

2015-12-01

Coastal marshes provide indispensable ecological functions, such as offering habitat for economic fish and wildlife, improving water quality, protecting inland areas from floods, and stabilizing the shoreline. Hurricanes—though helping to maintain the elevation of coastal wetlands by depositing large amounts of sediments—pose one of the largest threats for coastal marshes in terms of eroding shorelines, scouring marsh surfaces, and resuspending sediments. Coastal marshes phenologies can be important for understanding broad response of marshes to stressors, like hurricanes. We investigated the phenological impacts of Katrina and Gustav (Category 3 and 2 hurricanes at landfall in southeast Louisiana on 29 August, 2005, and 1 September, 2008, respectively) on freshwater, intermediate, brackish, and saline marshes in southeastern Louisiana. Landsat-derived Normalized Difference Vegetation Index data were processed using ENVI 4.8. Phenological patterns of the marshes were modeled using a nonlinear mixed model using SAS 9.4. We created and compared marsh phenologies of 1994 and 2014, the reference years, to those of 2005 and 2008, the hurricane years. Preliminary results show that in normal years: (1) the NDVI of four marsh types peaked in July; (2) freshwater marshes had the highest peak NDVI, followed by intermediate, brackish, and saline marshes; and (3) the growth durations of the marshes are around three to six months. In 2005, the major phenological change was shortening of growth duration, which was most obvious for intermediate and brackish marshes. The peak NDVI values of the four marsh types were not affected because the hurricane occurred at the end of August, one month after the peak NDVI time. By comparison, there was no obvious phenological impact on the marshes by Gustav (2008) with respect to peak NDVI, peak NDVI day, and growth duration.

Long-term effects of high-intensity interval training in heart transplant recipients: A 5-year follow-up study of a randomized controlled trial.

PubMed

Yardley, Marianne; Gullestad, Lars; Bendz, Bjørn; Bjørkelund, Elisabeth; Rolid, Katrine; Arora, Satish; Nytrøen, Kari

2017-01-01

Previous studies have demonstrated that high-intensity interval training (HIT) is superior to moderate-continuous exercise in general and in cardiovascular diseases. Recently, we also found HIT safe and efficient after heart transplantation (HTx). This study reports the 5-year long-term effects. Forty-one HTx patients who had completed the previous 12-month randomized controlled trial, comparing HIT intervention with usual care, were eligible. In particular, we measured VO 2peak , muscular capacity, intravascular ultrasound, and questionnaires measuring physical and mental health. The baseline mean±SD values were as follows: age; 49.1±16.5 years, men; 68%, time since HTx: 4.1±2.2 years. Within the HIT group, initial VO 2peak increased significantly from 27.7±5.7 to 31.2±5.3 mL/kg/min. However, during the next 4 years, VO 2peak decreased to 26.0±6.2 mL/kg/min. The control group showed slightly decreasing VO 2peak values during the entire 5-year period. The HIT group reported significantly less anxiety symptoms, but there were no long-term differences in VO 2peak , muscular capacity, or cardiac allograft vasculopathy between the groups. The similar VO 2peak values correspond to our findings of similar everyday activity. Our findings suggest that intermittent periods of HIT may be necessary to maintain the initial benefits gained from the intervention. However, HIT probably reduces the burden of anxiety, which is a frequent health issue following HTx. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Association of peak factor VIII levels and area under the curve with bleeding in patients with haemophilia A on every third day pharmacokinetic-guided prophylaxis.

PubMed

Valentino, L A; Pipe, S W; Collins, P W; Blanchette, V S; Berntorp, E; Fischer, K; Ewenstein, B M; Oh, M; Spotts, G

2016-07-01

We previously showed that pharmacokinetic-guided prophylaxis (PKP) allows the dosing interval to be extended while maintaining a specific trough level. However, the associations of peak factor VIII (FVIII) levels and area under the curve (AUC) with breakthrough bleeding have not been investigated. The aim of this study was to analyse data from the PKP arm to determine whether peak FVIII levels, AUC and time with FVIII levels in a haemostatically effective range are independent predictors of bleeding during prophylaxis. Post hoc analysis of the association of FVIII levels and AUC with annualized bleeding rate in 34 patients on PKP. During 1 year of PKP, 131 bleeding episodes occurred in 24/34 patients. Average peak FVIII levels ranged from 24 to 168 IU dL(-1) , with higher values associated with a decreased risk for all bleeding (joint and non-joint; P < 0.01) and joint bleeding (P < 0.01). Following rFVIII infusion, median percent of time spent with FVIII levels >20 IU dL(-1) was 22%; median AUC was 1363. Both values were significantly associated with a lower ABR when targeting a 1% trough at 72 h. When PKP was administered every third day, higher peak FVIII levels, higher AUC and more time spent per week with FVIII levels >20 IU dL(-1) provided increased protection from joint and non-joint bleeding. These data highlight the potential impact of variability in individual pharmacokinetic and bleeding risk and support the need for high peak levels and AUC in some patients treated every third day. The findings do not necessarily apply to alternate-day or other prophylactic dosing regimens. © 2016 The Authors. Haemophilia Published by John Wiley & Sons Ltd.

Submaximal exercise VO2 and Qc during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Ertl, A. C.; Bernauer, E. M.

1996-01-01

BACKGROUND: Maintaining intermediary metabolism is necessary for the health and well-being of astronauts on long-duration spaceflights. While peak oxygen uptake (VO2) is consistently decreased during prolonged bed rest, submaximal VO2 is either unchanged or decreased. METHODS: Submaximal exercise metabolism (61 +/- 3% peak VO2) was measured during ambulation (AMB day-2) and on bed rest days 4, 11, and 25 in 19 healthy men (32-42 yr) allocated into no exercise (NOE, N = 5) control, and isotonic exercise (ITE, N = 7) and isokinetic exercise (IKE, N = 7) training groups. Exercise training was conducted supine for two 30-min periods per day for 6 d per week: ITE training was intermittent at 60-90% peak VO2; IKE training was 10 sets of 5 repetitions of peak knee flexion-extension force at a velocity of 100 degrees s-1. Cardiac output was measured with the indirect Fick CO2 method, and plasma volume with Evans blue dye dilution. RESULTS: Supine submaximal exercise VO2 decreased significantly (*p < 0.05) by 10.3%* with ITE and by 7.3%* with IKE; similar to the submaximal cardiac output decrease of 14.5%* (ITE) and 20.3%* (IKE), but different from change in peak VO2 (+1.4% with ITE and -10.2%* with IKE) and decrease in plasma volume of -3.7% (ITE) and -18.0%* (IKE). Reduction of submaximal VO2 during bed rest correlated 0.79 (p < 0.01) with submaximal Qc, but was not related to change in peak VO2 or plasma volume. CONCLUSION: Reduction in submaximal oxygen uptake during prolonged bed rest is related to decrease in exercise but not resting cardiac output; perturbations in active skeletal muscle metabolism may be involved.

Understanding microbial/DOM interactions using fluorescence and flow cytometry

NASA Astrophysics Data System (ADS)

Fox, Bethany; Rushworth, Cathy; Attridge, John; Anesio, Alexandre; Cox, Tim; Reynolds, Darren

2015-04-01

The transformation and movement of dissolved organic carbon (DOC) within freshwater aquatic systems is an important factor in the global cycling of carbon. DOC within aquatic systems is known to underpin the microbial food web and therefore plays an essential role in supporting and maintaining the aquatic ecosystem. Despite this the interactions between bacteria and dissolved organic matter (DOM) are not well understood, although the literature indicates that the microbial processing of bioavailable DOM is essential during the production of autochthonous, labile, DOM. DOM can be broadly characterised by its fluorescing properties and Coble et al. (2014) define terrestrially derived DOM as exhibiting "peak C" fluorescence, whilst labile microbially derived DOM is defined as showing "peak T" fluorescence. Our work explores the microbial/DOM interactions by analysing aquatic samples using fluorescence excitation and emission matrices (EEMs) in conjunction with microbial consumption of dissolved oxygen. Environmental and synthetic water samples were subjected to fluorescence characterisation using both fluorescence spectroscopy and in situ fluorescence sensors (Chelsea Technologies Group Ltd.). PARAFAC analysis and peak picking were performed on EEMs and compared with flow cytometry data, used to quantify bacterial numbers present within samples. Synthetic samples were created using glucose, glutamic acid, nutrient-rich water and a standard bacterial seed. Synthetic samples were provided with terrestrially derived DOM via the addition of an aliquot of environmental water. Using a closed system approach, samples were incubated over time (up to a maximum of 20 days) and analysed at pre-defined intervals. The main focus of our work is to improve our understanding of microbial/DOM interactions and how these interactions affect both the DOM characteristics and microbial food web in freshwater aquatic systems. The information gained, in relation to the origin, microbial processing and subsequent production of DOM, will inform the development of a new generation of in situ fluorescence sensors. Ultimately, our aim is develop a novel technology that enables the monitoring of ecosystem health in freshwater aquatic systems.

Hand grip strength and maximum peak expiratory flow: determinants of bone mineral density of adolescent students.

PubMed

Cossio-Bolaños, Marco; Lee-Andruske, Cynthia; de Arruda, Miguel; Luarte-Rocha, Cristian; Almonacid-Fierro, Alejandro; Gómez-Campos, Rossana

2018-03-02

Maintaining and building healthy bones during the lifetime requires a complicated interaction between a number of physiological and lifestyle factors. Our goal of this study was to analyze the association between hand grip strength and the maximum peak expiratory flow with bone mineral density and content in adolescent students. The research team studied 1427 adolescent students of both sexes (750 males and 677 females) between the ages of 11.0 and 18.9 years in the Maule Region of Talca (Chile). Weight, standing height, sitting height, hand grip strength (HGS), and maximum peak expiratory flow (PEF) were measured. Furthermore, bone mineral density (BMD) and total body bone mineral content (BMC) were determined by using the Dual-Energy X-Ray Absorptiometry (DXA). Hand grip strength and PEF were categorized in tertiles (lowest, middle, and highest). Linear regression was performed in steps to analyze the relationship between the variables. Differences between categories were determined through ANOVA. In males, the hand grip strength explained 18-19% of the BMD and 20-23% of the BMC. For the females, the percentage of variation occurred between 12 and 13% of the BMD and 17-18% of the BMC. The variation of PEF for the males was observed as 33% of the BMD and 36% of the BMC. For the females, both the BMD and BMC showed a variation of 19%. The HGS and PEF were divided into three categories (lowest, middle, and highest). In both cases, significant differences occurred in bone density health between the three categories. In conclusion, the HGS and the PEF related positively to the bone density health of both sexes of adolescent students. The adolescents with poor values for hand grip strength and expiratory flow showed reduced values of BMD and BMC for the total body. Furthermore, the PEF had a greater influence on bone density health with respect to the HGS of the adolescents of both sexes.

Comparable Neutrophil Responses for Arm and Intensity-matched Leg Exercise.

PubMed

Leicht, Christof A; Goosey-Tolfrey, Victoria L; Bishop, Nicolette C

2017-08-01

Arm exercise is performed at lower absolute intensities than lower body exercise. This may impact on intensity-dependent neutrophil responses, and it is unknown whether individuals restricted to arm exercise experience the same changes in the neutrophil response as found for lower body exercise. Therefore, we aimed to investigate the importance of exercise modality and relative exercise intensity on the neutrophil response. Twelve moderately trained men performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak arms) and cycling (V˙O2peak legs): 1) arm cranking exercise at 60% V˙O2peak arms, 2) moderate cycling at 60% V˙O2peak legs, and 3) easy cycling at 60% V˙O2peak arms. Neutrophil numbers in the circulation increased for all exercise trials, but were significantly lower for easy cycling when compared with arm exercise (P = 0.009), mirroring the blunted increase in HR and epinephrine during easy cycling. For all trials, exercising HR explained some of the variation of the neutrophil number 2 h postexercise (R = 0.51-0.69), epinephrine explaining less of this variation (R = 0.21-0.34). The number of neutrophils expressing CXCR2 decreased in the recovery from exercise in all trials (P < 0.05). Arm and leg exercise elicits the same neutrophil response when performed at the same relative intensity, implying that populations restricted to arm exercise might achieve a similar exercise induced neutrophil response as those performing lower body exercise. A likely explanation for this is the higher sympathetic activation and cardiac output for arm and relative intensity-matched leg exercise when compared with easy cycling, which is partly reflected in HR. This study further shows that the downregulation of CXCR2 may be implicated in exercise-induced neutrophilia.

Effects of a 6-Week Aquatic Treadmill Exercise Program on Cardiorespiratory Fitness and Walking Endurance in Subacute Stroke Patients: A PILOT TRIAL.

PubMed

Han, Eun Young; Im, Sang Hee

2017-03-15

To assess the feasibility and safety of a 6-week course of water walking performed using a motorized aquatic treadmill in individuals with subacute stroke for cardiorespiratory fitness, walking endurance, and activities of daily living. Twenty subacute stroke patents were randomly assigned to aquatic treadmill exercise (ATE) or land-based exercise (LBE). The ATE group (n = 10) performed water-based aerobic exercise on a motorized aquatic treadmill, and the LBE group (n = 10) performed land-based aerobic exercise on a cycle ergometer. Both groups performed aerobic exercise for 30 minutes, 5 times per week for 6 weeks. Primary outcome measures were 6-minute walk test for walking endurance and cardiopulmonary fitness parameters of a symptom-limited exercise tolerance test, and secondary measures were Korean version of the Modified Barthel Index (K-MBI) for activities of daily living. All variables were assessed at baseline and at the end of the intervention. The ATE group showed significant improvements in 6-minute walk test (P = .005), peak oxygen uptake (V·o2peak; P = .005), peak heart rate (P = .007), exercise tolerance test duration (P = .005), and K-MBI (P = .008). The LBE group showed a significant improvement only in K-MBI (P = .012). In addition, improvement in V·o2peak was greater in the ATE than in the LBE group. This preliminary study showed that a 6-week ATE program improved peak aerobic capacity and walking endurance in patients with subacute stroke. The improvement in V·o2peak after an ATE exercise program was greater than that observed after an LBE program. Therefore, ATE effectively improves cardiopulmonary fitness in patients with subacute stroke.

The seasonal performance of a liquid-desiccant air conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenstein, A.; Novosel, D.

1995-08-01

Prior reports on liquid-desiccant systems have focused on their steady-state operation at ARI design conditions. By studying their performance during an entire cooling season, the computer modeling presented here shows that liquid-desiccant systems can have a very high seasonal coefficient of performance (COP). For a liquid-desiccant system that uses a double-effect boiler, COPs ranging from 1.44 in a humid location (Houston) to 2.24 in a dry location (Phoenix) are achieved by fully exploiting indirect evaporative cooling and providing only the minimum latent cooling needed to meet the loads on the building. This minimizes the amount of water absorbed by themore » desiccant and, hence, the amount of thermal energy needed to regenerate it. In applications where latent loads are very high, such as processing the high volumes of ventilation air required to maintain good indoor air quality, the liquid-desiccant air conditioner again has an advantage over vapor-compression equipment. In this study, a liquid-desiccant system is modeled that cools and dehumidifies only the ventilation air of an office building in Atlanta. Although processing an airstream that is only 25% of the total air delivered to the building, the liquid-desiccant system is able to meet 52% of the building`s seasonal cooling requirements and reduce the building`s peak electrical demand by about 47%.« less

Efficient Execution of Microscopy Image Analysis on CPU, GPU, and MIC Equipped Cluster Systems.

PubMed

Andrade, G; Ferreira, R; Teodoro, George; Rocha, Leonardo; Saltz, Joel H; Kurc, Tahsin

2014-10-01

High performance computing is experiencing a major paradigm shift with the introduction of accelerators, such as graphics processing units (GPUs) and Intel Xeon Phi (MIC). These processors have made available a tremendous computing power at low cost, and are transforming machines into hybrid systems equipped with CPUs and accelerators. Although these systems can deliver a very high peak performance, making full use of its resources in real-world applications is a complex problem. Most current applications deployed to these machines are still being executed in a single processor, leaving other devices underutilized. In this paper we explore a scenario in which applications are composed of hierarchical data flow tasks which are allocated to nodes of a distributed memory machine in coarse-grain, but each of them may be composed of several finer-grain tasks which can be allocated to different devices within the node. We propose and implement novel performance aware scheduling techniques that can be used to allocate tasks to devices. We evaluate our techniques using a pathology image analysis application used to investigate brain cancer morphology, and our experimental evaluation shows that the proposed scheduling strategies significantly outperforms other efficient scheduling techniques, such as Heterogeneous Earliest Finish Time - HEFT, in cooperative executions using CPUs, GPUs, and MICs. We also experimentally show that our strategies are less sensitive to inaccuracy in the scheduling input data and that the performance gains are maintained as the application scales.

Efficient Execution of Microscopy Image Analysis on CPU, GPU, and MIC Equipped Cluster Systems

PubMed Central

Andrade, G.; Ferreira, R.; Teodoro, George; Rocha, Leonardo; Saltz, Joel H.; Kurc, Tahsin

2015-01-01

High performance computing is experiencing a major paradigm shift with the introduction of accelerators, such as graphics processing units (GPUs) and Intel Xeon Phi (MIC). These processors have made available a tremendous computing power at low cost, and are transforming machines into hybrid systems equipped with CPUs and accelerators. Although these systems can deliver a very high peak performance, making full use of its resources in real-world applications is a complex problem. Most current applications deployed to these machines are still being executed in a single processor, leaving other devices underutilized. In this paper we explore a scenario in which applications are composed of hierarchical data flow tasks which are allocated to nodes of a distributed memory machine in coarse-grain, but each of them may be composed of several finer-grain tasks which can be allocated to different devices within the node. We propose and implement novel performance aware scheduling techniques that can be used to allocate tasks to devices. We evaluate our techniques using a pathology image analysis application used to investigate brain cancer morphology, and our experimental evaluation shows that the proposed scheduling strategies significantly outperforms other efficient scheduling techniques, such as Heterogeneous Earliest Finish Time - HEFT, in cooperative executions using CPUs, GPUs, and MICs. We also experimentally show that our strategies are less sensitive to inaccuracy in the scheduling input data and that the performance gains are maintained as the application scales. PMID:26640423

Denoising of Raman spectroscopy for biological samples based on empirical mode decomposition

NASA Astrophysics Data System (ADS)

León-Bejarano, Fabiola; Ramírez-Elías, Miguel; Mendez, Martin O.; Dorantes-Méndez, Guadalupe; Rodríguez-Aranda, Ma. Del Carmen; Alba, Alfonso

Raman spectroscopy of biological samples presents undesirable noise and fluorescence generated by the biomolecular excitation. The reduction of these types of noise is a fundamental task to obtain the valuable information of the sample under analysis. This paper proposes the application of the empirical mode decomposition (EMD) for noise elimination. EMD is a parameter-free and adaptive signal processing method useful for the analysis of nonstationary signals. EMD performance was compared with the commonly used Vancouver algorithm (VRA) through artificial data (Teflon), synthetic (Vitamin E and paracetamol) and biological (Mouse brain and human nails) Raman spectra. The correlation coefficient (ρ) was used as performance measure. Results on synthetic data showed a better performance of EMD (ρ=0.52) at high noise levels compared with VRA (ρ=0.19). The methods with simulated fluorescence added to artificial material exhibited a similar shape of fluorescence in both cases (ρ=0.95 for VRA and ρ=0.93 for EMD). For synthetic data, Raman spectra of vitamin E were used and the results showed a good performance comparing both methods (ρ=0.95 for EMD and ρ=0.99 for VRA). Finally, in biological data, EMD and VRA displayed a similar behavior (ρ=0.85 for EMD and ρ=0.96 for VRA), but with the advantage that EMD maintains small amplitude Raman peaks. The results suggest that EMD could be an effective method for denoising biological Raman spectra, EMD is able to retain information and correctly eliminates the fluorescence without parameter tuning.

An Ecological Study of Anterior Cruciate Ligament Reconstruction, Part 2: Functional Performance Tests Correlate With Return-to-Sport Outcomes.

PubMed

McGrath, Timothy M; Waddington, Gordon; Scarvell, Jennie M; Ball, Nick; Creer, Rob; Woods, Kevin; Smith, Damian; Adams, Roger

2017-02-01

Additional high-quality prospective studies are needed to better define the objective criteria used in relation to return-to-sport decisions after anterior cruciate ligament (ACL) reconstruction in active populations. To investigate prospectively the relationship between functional performance test results at 24 weeks postoperative and return-to-sport activity (Tegner activity score) at 12 and 24 months, respectively, after synthetic (ligament advanced reinforcement system [LARS]) and autograft (doubled semitendinosus/gracilis [2ST/2GR]) ACL reconstructions. Case series; Level of evidence, 4. A total of 64 patients who underwent ACL reconstruction (32 LARS, 32 2ST/2GR autograft; mean age, 27.9 years; body mass index [BMI], 24.9 kg/m 2 ) were assessed preoperatively and at staged intervals postoperatively up to 24 weeks for isokinetic testing of quadriceps and hamstring average power per repetition at 60 deg/s and 180 deg/s, a battery of hop tests, peak vertical ground-reaction force (vGRF), and time to peak vGRF (in seconds) during a step- and jump-down task onto a force platform and peak speed (m/s) using a global positioning system (GPS unit) during a running task. A cohort of 32 healthy matched participants (mean age, 26.31 years; BMI, 25.7 kg/m 2 ) were also tested to act as reference. Pearson correlation was calculated to assess correlation of each performance measure at 24 weeks postoperative with activity outcomes (Tegner score) at 12 and 24 months. The strongest correlation between physical performance tests and return-to-sport outcomes was observed with peak speed during running. Large correlations were also observed for hamstring isokinetic power and hop test for distance. Moderate correlations were observed for timed hop, peak vGRF during a jump-down task, and quadriceps isokinetic power. No statistical correlations were observed for time to peak vGRF during a step-down and jump-down task as well as peak vGRF during a step-down task. When the performance tests were pooled together, mean postoperative improvements of 24% were observed from preoperative to 24 weeks within the surgical cohort. For each performance test, preoperative level of function strongly correlated with performance levels on the same test at 24 weeks. The results of this study indicate that clinicians might seek to prioritize these tests and the rehabilitation themes they imply when seeking to maximize postoperative ACL activity outcomes. The observed strength between pre- and postoperative performance tests and return-to-sport outcomes within this study highlights the potential value of preoperative conditioning before undergoing ACL reconstruction. Future research should examine absolute predictive criterion thresholds for functional performance-based tests and reinjury risk reduction after ACL reconstruction.

On a simulation study for reliable and secured smart grid communications

NASA Astrophysics Data System (ADS)

Mallapuram, Sriharsha; Moulema, Paul; Yu, Wei

2015-05-01

Demand response is one of key smart grid applications that aims to reduce power generation at peak hours and maintain a balance between supply and demand. With the support of communication networks, energy consumers can become active actors in the energy management process by adjusting or rescheduling their electricity usage during peak hours based on utilities pricing incentives. Nonetheless, the integration of communication networks expose the smart grid to cyber-attacks. In this paper, we developed a smart grid simulation test-bed and designed evaluation scenarios. By leveraging the capabilities of Matlab and ns-3 simulation tools, we conducted a simulation study to evaluate the impact of cyber-attacks on demand response application. Our data shows that cyber-attacks could seriously disrupt smart grid operations, thus confirming the need of secure and resilient communication networks for supporting smart grid operations.

Optimized phase mask to realize retro-reflection reduction for optical systems

NASA Astrophysics Data System (ADS)

He, Sifeng; Gong, Mali

2017-10-01

Aiming at the threats to the active laser detection systems of electro-optical devices due to the cat-eye effect, a novel solution is put forward to realize retro-reflection reduction in this paper. According to the demands of both cat-eye effect reduction and the image quality maintenance of electro-optical devices, a symmetric phase mask is achieved from a stationary phase method and a fast Fourier transform algorithm. Then, based on a comparison of peak normalized cross-correlation (PNCC) between the different defocus parameters, the optimal imaging position can be obtained. After modification with the designed phase mask, the cat-eye effect peak intensity can be reduced by two orders of magnitude while maintaining good image quality and high modulation transfer function (MTF). Furthermore, a practical design example is introduced to demonstrate the feasibility of our proposed approach.

Potential for chlorate interference in ion chromatographic determination of total nitrogen in natural waters following alkaline persulfate digestion.

PubMed

Halstead, J A; Edwards, J; Soracco, R J; Armstrong, R W

1999-10-01

Determination of total nitrogen in aqueous samples after thermal potassium peroxydisulfate (persulfate) digestion is a commonly used alternative to the tedious Kjeldahl procedure. When ion chromatography is used to quantify the nitrate formed during digestion, there is a potential for interference from a chlorate peak if the digested sample initially contained chloride in concentrations close to or greater than the concentration of nitrogen. It was determined that this interference can be avoided either by using chromatographic conditions which cleanly resolve the nitrate and chlorate peaks (e.g., the Dionex AG9-HG column) or by using digestion reagent concentrations chosen to maintain a high pH throughout the digestion. The second alternative is not a viable option for investigators using a single digestion for both total nitrogen (TN) and total phosphorus (TP) analysis.

NFκB–Pim-1–Eomesodermin axis is critical for maintaining CD8 T-cell memory quality

PubMed Central

Knudson, Karin M.; Saxena, Vikas; Altman, Amnon; Daniels, Mark A.; Teixeiro, Emma

2017-01-01

T-cell memory is critical for long-term immunity. However, the factors involved in maintaining the persistence, function, and phenotype of the memory pool are undefined. Eomesodermin (Eomes) is required for the establishment of the memory pool. Here, we show that in T cells transitioning to memory, the expression of high levels of Eomes is not constitutive but rather requires a continuum of cell-intrinsic NFκB signaling. Failure to maintain NFκB signals after the peak of the response led to impaired Eomes expression and a defect in the maintenance of CD8 T-cell memory. Strikingly, we found that antigen receptor [T-cell receptor (TCR)] signaling regulates this process through expression of the NFκB-dependent kinase proviral integration site for Moloney murine leukemia virus-1 (PIM-1), which in turn regulates NFκB and Eomes. T cells defective in TCR-dependent NFκB signaling were impaired in late expression of Pim-1, Eomes, and CD8 memory. These defects were rescued when TCR-dependent NFκB signaling was restored. We also found that NFκB–Pim-1 signals were required at memory to maintain memory CD8 T-cell longevity, effector function, and Eomes expression. Hence, an NFκB–Pim-1–Eomes axis regulates Eomes levels to maintain memory fitness. PMID:28193872

Simulated Reentry Heating by Torching

NASA Technical Reports Server (NTRS)

Harvey, Gale A.

2008-01-01

The two first order reentry heating parameters are peak heating flux (W/cm2) and peak heat load (kJ/cm2). Peak heating flux (and deceleration, gs) is higher for a ballistic reentry and peak heat load is higher for a lifting reentry. Manned vehicle reentries are generally lifting reentries at nominal 1-5 gs so that personnel will not be crushed by high deceleration force. A few off-nominal manned reentries have experienced 8 or more gs with corresponding high heating flux (but below nominal heat load). The Shuttle Orbiter reentries provide about an order of magnitude difference in peak heating flux at mid-bottom (TPS tiles, approximately 6 W/cm2 or 5 BTU/ft2- sec) and leading edge (RCC, approximately 60 W/cm2 or 50 BTU/ft2- sec). Orion lunar return and Mars sample lander are of the same order of magnitude as orbiter leading edge peak heat loads. Flight temperature measurements are available for some orbiter TPS tile and RCC locations. Return-to-Flight on-orbit tile-repair-candidate-material-heating performance was evaluated by matching propane torch heating of candidate-materials temperatures at several depths to orbiter TPS tile flight-temperatures. Char and ash characteristics, heat expansion, and temperature histories at several depths of the cure-in-place ablator were some of the TPS repair material performance characteristics measured. The final char surface was above the initial surface for the primary candidate (silicone based) material, in contrast to a receded surface for the Apollo-type ablative heat shield material. Candidate TPS materials for Orion CEV (LEO and lunar return), and for Mars sample lander are now being evaluated. Torching of a candidate ablator material, PICA, was performed to match the ablation experienced by the STARDUST PICA heat shield. Torching showed that the carbon fiberform skeleton in a sample of PICA was inhomogeneous in that sample, and allowed measurements (of the clumps and voids) of the inhomogeneity. Additional reentry heating-performance characterizations of high temperature insulation materials were performed.