Search

Strength of religious faith of athletes and nonathletes attending (a) a religiously practicing institution (RPI) and (b) a non-religiously practicing (NRPI) institution in NCAA's Division III was studied using the Santa Clara Strength of Religious Faith Questionnaire. A 2 × 2 × 2 ANOVA sought differences in strength of faith of RPI students (n = 201) versus NRPI students (n = 174). Results show RPI students displayed stronger faith than NRPI students, F(1, 367) = 25.44, p < .01. A significant interaction showed RPI nonathletes more faithful than RPI athletes, F(1, 367) = 6.73, p < .05; NRPI athletes did not differ significantly from NRPI nonathletes. Women's faith was stronger than men's, F(1, 367) = 12.99, p < .01. [ABSTRACT FROM AUTHOR]

Large and stout snakes commonly consume large prey and use rectilinear crawling; yet, whether body wall distention after feeding impairs rectilinear locomotion is poorly understood. After eating large prey (30-37% body mass), all Boa constrictor tested could perform rectilinear locomotion in the region with the food bolus despite a greatly increased distance between the ribs and the ventral skin that likely lengthens muscles relevant to propulsion. Unexpectedly, out of 11 kinematic variables, only two changed significantly (P<0.05) after feeding: cyclic changes in snake height increased by more than 1.5 times and the longitudinal movements of the ventral skin relative to the skeleton decreased by more than 25%. Additionally, cyclic changes in snake width suggest that the ribs are active and mobile during rectilinear locomotion, particularly in fed snakes, but also in unfed snakes. These kinematic changes suggest that rectilinear actuators reorient more vertically and undergo smaller longitudinal excursions following large prey ingestion, both of which likely act to reduce elongation of these muscles that may otherwise experience substantial strain., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Many animals use a combination of skeletal muscle and elastic structures to amplify power output for fast motions. Among vertebrates, tendons in series with skeletal muscle are often implicated as the primary power-amplifying spring, but muscles contain elastic structures at all levels of organization, from the muscle tendon to the extracellular matrix to elastic proteins within sarcomeres. The present study used ex vivo muscle preparations in combination with high-speed video to quantify power output, as the product of force and velocity, at several levels of muscle organization to determine where power amplification occurs. Dynamic ramp-shortening contractions in isolated frog flexor digitorum superficialis brevis were compared with isotonic power output to identify power amplification within muscle fibers, the muscle belly, free tendon and elements external to the muscle tendon. Energy accounting revealed that artifacts from compliant structures outside of the muscle-tendon unit contributed significant peak instantaneous power. This compliance included deflection of clamped bone that stored and released energy contributing 195.22±33.19 W kg-1 (mean±s.e.m.) to the peak power output. In addition, we found that power detected from within the muscle fascicles for dynamic shortening ramps was 338.78±16.03 W kg-1, or approximately 1.75 times the maximum isotonic power output of 195.23±8.82 W kg-1. Measurements of muscle belly and muscle-tendon unit also demonstrated significant power amplification. These data suggest that intramuscular tissues, as well as bone, have the capacity to store and release energy to amplify whole-muscle power output., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

We report on the use of quartz-enhanced photoacoustic spectroscopy (QEPAS) for multi-gas detection. Photoacoustic (PA) spectra of mixtures of water (H2O), ammonia (NH3), and methane (CH4) were measured in the mid-infrared (MIR) wavelength range using a mid-infrared (MIR) optical parametric oscillator (OPO) light source. Highly overlapping absorption spectra are a common challenge for gas spectroscopy. To mitigate this, we used a partial least-squares regression (PLS) method to estimate the mixing ratio and concentrations of the individual gasses. The concentration range explored in the analysis varies from a few parts per million (ppm) to thousands of ppm. Spectra obtained from HITRAN and experimental single-molecule reference spectra of each of the molecular species were acquired and used as training data sets. These spectra were used to generate simulated spectra of the gas mixtures (linear combinations of the reference spectra). Here, in this proof-of-concept experiment, we demonstrate that after an absolute calibration of the QEPAS cell, the PLS analyses could be used to determine concentrations of single molecular species with a relative accuracy within a few % for mixtures of H2O, NH3, and CH4 and with an absolute sensitivity of approximately 300 (±50) ppm/V, 50 (±5) ppm/V, and 5 (±2) ppm/V for water, ammonia, and methane, respectively. This demonstrates that QEPAS assisted by PLS is a powerful approach to estimate concentrations of individual gas components with considerable spectral overlap, which is a typical scenario for real-life adoptions and applications.

There is a great need for cost-efficient non-invasive medical diagnostic tools for analyzing humanly exhaled air. Compared to present day methods, photoacoustic spectroscopy (PAS) can provide a compact and portable (bedside), sensitive and inexpensive solution. We demonstrate a novel portable photoacoustic spectroscopic platform for isotopic measurements of methane ( C H 4 ). We identify and discriminate the 12 C H 4 - and 13 C H 4 isotopologues and determine their mixing ratio. An Allan deviation analysis shows that the noise equivalent concentration for C H 4 is 200 ppt (pmol/mol) at 100 s of integration time, corresponding to a normalized noise equivalent absorption coefficient of 5.1×10 -9 W c m -1 H z -1/2 , potentially making the PAS sensor a truly disruptive instrument for bedside monitoring using isotope tracers by providing real-time metabolism data to clinical personnel.

Despite the continued growth of the Olympic Games (OG), the Youth Olympic Games (YOG) has received minimal attention from mainstream media since its introduction in 2010. The purpose of this study was to examine and compare event awareness and consumption intention for the 2012 Winter YOG to two international sport events occurring in the same year. A survey instrument was utilized to examine and compare event awareness, consumption intention, and logo identification for three international sport events within a millennial generation sample. The study showed significant differences in personal and public awareness between the three sport events, with personal ( r = .313, p ≤ .001) and public (r = .331, p ≤ .001) awareness for the YOG demonstrating a positive correlation with consumption intention. This study is an important assessment of the YOG event awareness that can be utilized by the International Olympic Committee (IOC) to better understand and engage their participants and audience. Successful promotion of the YOG may require a transformation of the current marketing strategies that are utilized. The YOG has great opportunity for success in the global sport market to leave behind the status of the best kept secret in sport.

We report on the use of quartz-enhanced photoacoustic spectroscopy for continuous carbon-dioxide measurements in humid air over a period of six days. The presence of water molecules alters the relaxation rate of the target molecules and thus the amplitude of the photoacoustic signal. Prior to the measurements, the photoacoustic sensor system was pre-calibrated using CO 2 mole fractions in the range of 0-10 -3 (0-1000 ppm) and at different relative humidities between 0% and 45%, while assuming a model hypothesis that allowed the photoacoustic signal to be perturbed linearly by H 2 O content. This calibration technique was compared against an alternative learning-based method, where sensor data from the first two days of the six-day period were used for self-calibration. A commercial non-dispersive infrared sensor was used as a CO 2 reference sensor and provided the benchmark for the two calibration procedures. In our case, the self-calibrated method proved to be both more accurate and precise.

Fish fin rays (lepidotrichia) are typically composed of paired and segmented flexible structures (hemitrichia) that help support and change the shape of the fins to affect water flow. Yet, marine ray-finned fish that are members of the family Priontinae (sea-robins) have specialized pectoral fin rays that are separated from the fin and used as limbs to walk along the seafloor. While previous kinematic studies have demonstrated the use of these specialized fin rays as walking appendages, there is little information on how the morphology of the 'walking rays' and associated musculature facilitate underwater walking. Here, we examine the musculoskeletal anatomy of the walking and pectoral fin rays in the striped sea-robin Prionotus evolans and compare the mechanical properties of the rays with those of the smaller northern sea-robin Prionotus carolinus We aimed to determine what structural modifications in the walking rays allow them to function as a supportive limb. We found enlarged processes for muscle attachment, bone extensions that brace the hemitrich articulations, and reduced flexibility and increased second moment of area along the rostro-caudal bending axis in the rays used for walking. This novel limb design may have promoted the benthic foraging behavior exhibited by these species by uncoupling locomotion and feeding., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)

Background and Objectives: National Collegiate Athletic Association (NCAA) soccer coaches implement numerous warm-up and flexibility strategies to prepare athletes for training and competition. The Fédération Internationale de Football Association (FIFA) developed the 11+ injury prevention program to reduce non-contact injuries. This study aimed to analyze the level of familiarity with and implementation of the evidence-based FIFA 11+ amongst NCAA Division I (DI) and Division III (DIII) men's and women's soccer coaches. Materials and Methods: NCAA soccer coaches in the United States received an Institutional Review Board-approved survey hyperlink. A total of 240 coaches completed the survey. The respondents represented 47.5% men's and 52.5% women's teams distributed within DI and DIII programs. Descriptive statistics are reported as frequency counts and mean ± standard deviation where applicable. Pearson's chi-square tests were performed to assess potential differences with a significance level set at α < 0.05. Results: The results indicated that approximately 62% of the respondents reported being familiar with the FIFA 11+ program. Of those coaches familiar with the program, 15.0% reported full implementation, 57.5% reported partial implementation, and 27.5% reported no implementation. Chi-square analyses revealed significant differences in FIFA 11+ implementation based upon division level (χ 2 = 4.56, p = 0.033) and coaching certification levels (χ 2 = 13.11, p = 0.011). Conclusions: This study indicates that there is a gap between FIFA 11+ knowledge and actual implementation. To reduce the risk of non-contact injury, there is a need to educate coaches and athletic trainers on the purpose of the FIFA 11+ program and how to perform the exercises correctly.

Raman spectroscopy is an appealing technique that probes molecular vibrations in a wide variety of materials with virtually no sample preparation. However, accurate and reliable Raman measurements are still a challenge and require more robust and practical calibration methods. We demonstrate the implementation of a simple low-cost continuous-wave (cw) stimulated Raman spectroscopy scheme for accurate and high-resolution spectroscopy. We perform shot noise-limited cw stimulated Raman scattering as well as cw coherent anti-Stokes Raman scattering on polystyrene samples. Our method enables accurate determination of Raman shifts with an uncertainty below 0.1  cm -1 . The setup is used for the characterization of reference materials required for the calibration of Raman spectrometers. Compared with existing standards, we provide an order of magnitude improvement of the uncertainty of Raman energy shifts in a polystyrene reference material.

Standard laser-based fire detection systems are often based on measuring the variation of optical signal amplitude. However, mechanical noise interference and loss from dust and steam can obscure the detection signal, resulting in faulty results or the inability to detect a potential fire. The presented fire detection technology will allow the detection of fire in harsh and dusty areas, which are prone to fires, where current systems show limited performance or are unable to operate. It is not the amount of light or its wavelength that is used for detecting fire, but how the refractive index randomly fluctuates due to heat convection from the fire. In practical terms, this means that light obstruction from ambient dust particles will not be a problem as long as a small fraction of the light is detected and that fires without visible flames can still be detected. The standalone laser system consists of a Linux-based Red Pitaya system, a cheap 650 nm laser diode, and a positive-intrinsic-negative photo-detector. Laser light propagates through the monitored area and reflects off a retroreflector generating a speckle pattern. Every 3 s, time traces and frequency noise spectra are measured, and eight descriptors are deduced to identify a potential fire. Both laboratory and factory acceptance tests have been performed with success.

A pseudoaneurysm located at the subclavian artery ostium is an infrequent but life-threatening pathology that usually requires major thoracic surgery with a high risk of mortality and morbidity. Endovascular therapy applied to the aortic arch branches is a recent alternative technique, which is still in its early stages because dedicated endovascular devices for the aortic arch are lacking. In this article, we present the emergency endovascular management of a symptomatic pseudoaneurysm of the left subclavian artery ostium which was presumably secondary to an atherosclerotic plaque rupture. Endovascular exclusion required a combination of an abdominal aortic stent-graft extension cuff, which was placed via a retroperitoneal iliac access, and a subclavian artery periscope stent graft., (Copyright © 2018 Elsevier Inc. All rights reserved.)

We demonstrate the usefulness of a nanosecond-pulsed single-mode mid-infrared (MIR) optical parametric oscillator (OPO) for photoacoustic (PA) spectroscopic measurements. The maximum wavelength ranges for the signal and idler are 1.4 μm to 1.7 μm and 2.8 μm to 4.6 μm, respectively, with a MIR output power of up to 500 mW, making the OPO useful for different spectroscopic PA trace-gas measurements targeting the major market opportunity of environmental monitoring and breath gas analysis. We perform spectroscopic measurements of methane (CH 4 ), nitrogen dioxide (NO 2 ), and ammonia (NH 3 ) in the 2.8 μm to 3.7 μm wavelength region. The measurements were conducted with a constant flow rate of 300 mL/min, thus demonstrating the suitability of the gas sensor for real-time trace-gas measurements. The acquired spectra are compared with data from the HITRAN database, and good agreement is found, demonstrating a resolution bandwidth of 1.5  cm 1 . An Allan deviation analysis shows that the detection limit for methane at optimum integration time for the PA sensor is 8 ppbV (nmol/mol) at 105 s of integration time, corresponding to a normalized noise equivalent absorption coefficient of 2.9×10 -7   W cm -1   Hz -1/2 .

This publisher's note corrects an affiliation error in Opt. Lett.41, 4118 (2016)OPLEDP0146-959210.1364/OL.41.004118.

A photoacoustic (PA) sensor for fast and real-time gas sensing is demonstrated. The PA sensor is a stand-alone system controlled by a field-programmable gate array. The PA cell has been designed for flow noise immunity using computational fluid dynamics (CFD) analysis. The aim of the CFD analysis was to investigate and minimize the influence of the gas distribution and flow noise on the PA signal. PA measurements were conducted at different flow rates by exciting molecular C-H stretch vibrational bands of hexane (C 6 H 14 ) and decane (C 10 H 22 ) molecules in clean air at 2950  cm -1 (3.38 μm) with a custom-made mid-infrared interband cascade laser. We observe a (1σ, standard deviation) sensitivity of 0.4±0.1  ppb (nmol/mol) for hexane in clean air at flow rates up to 1.7 L/min, corresponding to a normalized noise equivalent absorption coefficient of 2.5×10 -9   W cm -1   Hz -1/2 , demonstrating high sensitivity and fast real-time gas analysis. An Allan deviation analysis for decane shows that the detection limit at optimum integration time is 0.25 ppbV (nmol/mol).

Context:   Athletic training facilities have been described in terms of general design concepts and from operational perspectives. However, the size and scope of athletic training facilities, along with staffing at different levels of intercollegiate competition, have not been quantified., Objective:   To define the size and scope of athletic training facilities and staffing levels at various levels of intercollegiate competition. To determine if differences existed in facilities (eg, number of facilities, size of facilities) and staffing (eg, full time, part time) based on the level of intercollegiate competition., Design:   Cross-sectional study., Setting:   Web-based survey., Patients or Other Participants:   Athletic trainers (ATs) who were knowledgeable about the size and scope of athletic training programs., Main Outcome Measure(s):   Athletic training facility size in square footage; the AT's overall facility satisfaction; athletic training facility component spaces, including satellite facilities, game-day facilities, offices, and storage areas; and staffing levels, including full-time ATs, part-time ATs, and undergraduate students., Results:   The survey was completed by 478 ATs (response rate = 38.7%) from all levels of competition. Sample means for facilities were 3124.7 ± 4425 ft 2 (290.3 ± 411 m 2 ) for the central athletic training facility, 1013 ± 1521 ft 2 (94 ± 141 m 2 ) for satellite athletic training facilities, 1272 ± 1334 ft 2 (118 ± 124 m 2 ) for game-day athletic training facilities, 388 ± 575 ft 2 (36 ± 53 m 2 ) for athletic training offices, and 424 ± 884 ft 2 (39 ± 82 m 2 ) for storage space. Sample staffing means were 3.8 ± 2.5 full-time ATs, 1.6 ± 2.5 part-time ATs, 25 ± 17.6 athletic training students, and 6.8 ± 7.2 work-study students. Division I schools had greater resources in multiple categories (P < .001). Differences among other levels of competition were not as well defined. Expansion or renovation of facilities in recent years was common, and almost half of ATs reported that upgrades have been approved for the near future., Conclusions:   This study provides benchmark descriptive data on athletic training staffing and facilities. The results (1) suggest that the ATs were satisfied with their facilities and (2) highlight the differences in resources among competition levels.

We demonstrate a compact and versatile laser system for stimulated Raman spectroscopy (SRS). The system is based on a tunable continuous wave (CW) probe laser combined with a home-built semi-monolithic nanosecond pulsed pump Nd:YVO 4 laser at 1064 nm. The CW operation of the probe laser offers narrow linewidth, low noise and the advantage that temporal synchronization with the pump is not required. The laser system enables polarization-sensitive stimulated Raman spectroscopy (PS-SRS) with fast high resolution measurement of the depolarization ratio by simultaneous detection of Raman scattered light in orthogonal polarizations, thus providing information about the symmetry of the Raman-active vibrational modes. Measurements of the depolarization ratios of the carbon-hydrogen (CH) stretching modes in two different polymer samples in the spectral range of 2825-3025 cm -1 were performed. Raman spectra are obtained at a sweep rate of 20 nm/s (84 cm -1 /s) with a resolution of 0.65 cm -1 . A normalization method is introduced for the direct comparison of the simultaneously acquired orthogonal polarized Raman spectra.

We demonstrate an online (in-situ) sensor for continuous detection of oil contamination in compressed air systems complying with the ISO-8573 standard. The sensor is based on the photo-acoustic (PA) effect. The online and real-time PA sensor system has the potential to benefit a wide range of users that require high purity compressed air. Among these are hospitals, pharmaceutical industries, electronics manufacturers, and clean room facilities. The sensor was tested for sensitivity, repeatability, robustness to molecular cross-interference, and stability of calibration. Explicit measurements of hexane (C 6 H 14 ) and decane (C 10 H 22 ) vapors via excitation of molecular C-H vibrations at approx. 2950 cm -1 (3.38 μm) were conducted with a custom made interband cascade laser (ICL). For the decane measurements a (1 σ) standard deviation (STD) of 0.3 ppb was demonstrated, which corresponds to a normalized noise equivalent absorption (NNEA) coefficient for the prototype PA sensor of 2.8×10 -9 W cm -1 Hz 1/2 .

We present a method using an ordinary color camera to characterize nanostructures from the visual color of the structures. The method provides a macroscale overview image from which micrometer-sized regions can be analyzed independently, hereby revealing long-range spatial variations of the structures. The method is tested on injection-molded polymer line gratings, and the height and filling factor are determined with confidence intervals similar to more advanced imaging scatterometry setups.

A trace-gas sensor, based on quartz-enhanced photoacoustic spectroscopy (QEPAS), consisting of two acoustically coupled micro-resonators (mR) with an off-axis 20 kHz quartz tuning fork (QTF) is demonstrated. The complete acoustically coupled mR system is optimized based on finite-element simulations and is experimentally verified. The QEPAS sensor is pumped resonantly by a nanosecond pulsed single-mode mid-infrared optical parametric oscillator. The sensor is used for spectroscopic measurements on methane in the 3.1-3.5 μm wavelength region with a resolution bandwidth of 1  cm -1 and a detection limit of 0.8 ppm. An Allan deviation analysis shows that the detection limit at the optimum integration time for the QEPAS sensor is 32 ppbv at 190 s, and that the background noise is due solely to the thermal noise of the QTF.

We evaluated postural effects on intracranial pressure (ICP) and cerebral perfusion pressure [CPP: mean arterial pressure (MAP) - ICP] in neurosurgical patients undergoing 24-h ICP monitoring as part of their diagnostic workup. We identified nine patients (5 women, age 44 ± 20 yr; means ± SD), who were "as normal as possible," i.e., without indication for neurosurgical intervention (e.g., focal lesions, global edema, abnormalities in ICP-profile, or cerebrospinal fluid dynamics). ICP (tip-transducer probe; Raumedic) in the brain parenchyma (n = 7) or in the lateral ventricles (n = 2) and cardiovascular variables (Nexfin) were determined from 20° head-down tilt to standing up. Compared with the supine position, ICP increased during 10° and 20° of head-down tilt (from 9.4 ± 3.8 to 14.3 ± 4.7 and 19 ± 4.7 mmHg; P < 0.001). Conversely, 10° and 20° head-up tilt reduced ICP to 4.8 ± 3.6 and 1.3 ± 3.6 mmHg and ICP reached -2.4 ± 4.2 mmHg in the standing position (P < 0.05). Concordant changes in MAP maintained CPP at 77 ± 7 mmHg regardless of body position (P = 0.95). During head-down tilt, the increase in ICP corresponded to a hydrostatic pressure gradient with reference just below the heart, likely reflecting the venous hydrostatic indifference point. When upright, the decrease in ICP was attenuated, corresponding to formation of a separate hydrostatic gradient with reference to the base of the skull, likely reflecting the site of venous collapse. ICP therefore seems to be governed by pressure in the draining veins and collapse of neck veins may protect the brain from being exposed to a large negative pressure when upright. Despite positional changes in ICP, MAP keeps CPP tightly regulated., (Copyright © 2016 the American Physiological Society.)

The purpose of this study was to analyze the level of creatine use along with the perceived benefits and barriers of creatine use among collegiate athletes who participate in throwing events within the sport of track and field. A total of 258 throwers from National Collegiate Athletic Association Division I institutions completed an online survey regarding creatine. The results provided baseline levels of creatine use and allowed for the analysis of factors related to athletic conference affiliation. Results indicate that creatine use remains to be a common (32.7%) practice among throwers with significantly higher levels of use among Football Bowl Subdivision (FBS) conference athletes (44.6%) than Football Championship Subdivision (FCS) conference athletes (28.8%), χ² = 5.505, p = 0.019. The most common reasons for using creatine included a desire to improve/increase: strength (83.3%), recovery time (69.0%), and performance (60.7%). The most common perceived obstacles included contamination/quality control (39.5%), cost (33.3%), inconvenience (16.7%), and cramping (14.3%). A desire for additional education and training was noted through an expression of interest (55.6%) with significantly higher levels of interest from FBS athletes (65.6%) than FCS athletes (52.2%), χ² = 6.425, p = 0.039. However, the athletic departments provide nutritional supplement counseling at only 26.6% of the schools. Although the access to full-time nutritionist counsel was available at 57.3% of the schools, there was a significant difference (χ² = 9.096, p = 0.003) between FBS schools (73.7%) and FCS schools (51.7%).

We demonstrate sensitive high-resolution stimulated Raman measurements of hydrogen using a hollow-core photonic crystal fiber (HC-PCF). The Raman transition is pumped by a narrow linewidth (< 50 kHz) 1064 nm continuous-wave (CW) fiber laser. The probe light is produced by a homebuilt CW optical parametric oscillator (OPO), tunable from around 800 nm to 1300 nm (linewidth ∼ 5 MHz). These narrow linewidth lasers allow for an excellent spectral resolution of approximately 10(-4) cm(-1). The setup employs a differential measurement technique for noise rejection in the probe beam, which also eliminates background signals from the fiber. With the high sensitivity obtained, Raman signals were observed with only a few mW of optical power in both the pump and probe beams. This demonstration allows for high resolution Raman identification of molecules and quantification of Raman signal strengths.

The recent demonstration of saturable absorption and negative optical conductivity in the Terahertz range in graphene has opened up new opportunities for optoelectronic applications based on this and other low dimensional materials. Recently, population inversion across the Dirac point has been observed directly by time- and angle-resolved photoemission spectroscopy (tr-ARPES), revealing a relaxation time of only ∼130 femtoseconds. This severely limits the applicability of single layer graphene to, for example, Terahertz light amplification. Here we use tr-ARPES to demonstrate long-lived population inversion in bilayer graphene. The effect is attributed to the small band gap found in this compound. We propose a microscopic model for these observations and speculate that an enhancement of both the pump photon energy and the pump fluence may further increase this lifetime.

Strength and conditioning training programs are essential components of athletic performance, and the effectiveness of these programs can be linked to the strength and conditioning facilities (SCFs) used by athletes. The primary purpose of this study was to provide a statistical overview of National Collegiate Athletic Association (NCAA) Division I SCFs, equipment and maintenance budget, and the relationship between SCF budget and staffing space, and equipment. The secondary purpose was to note differences in SCFs between those schools with and without football programs. An 84-item online survey instrument, developed with expert input from certified strength professionals, was used to collect data regarding the SCFs in NCAA Division I universities. A total of 110 valid and complete surveys were returned for a response rate of 38.6%. Results of Pearson's χ2 analysis demonstrated that the larger reported annual equipment budgets were associated with larger SCFs (χ2 = 451.4, p ≤ 0.001), greater maximum safe capacity of athletes using the facility (χ2 = 366.9, p ≤ 0.001), increased numbers of full-time coaches (χ2 = 224.2, p ≤ 0.001), and increased number of graduate assistant or intern coaches (χ2 = 102.9, p ≤ 0.001). Based on these data, it can be suggested to athletic administrators and strength and conditioning professionals at the collegiate level that budgets need to be re-evaluated as the number of personnel available to monitor student-athletes and the size and safe capacity of the facility are related to the ability of the strength and conditioning staff to safely and adequately perform their duties.

A compact versatile photoacoustic (PA) sensor for trace gas detection is reported. The sensor is based on an integrating sphere as the PA absorption cell with an organ pipe tube attached to increase the sensitivity of the PA sensor. The versatility and enhancement of the sensitivity of the PA signal is investigated by monitoring specific ro-vibrational lines of CO(2) in the 2 μm wavelength region and of NO(2) in the 405 nm region. The measured enhancement factor of the PA signal exceeds 1200, which is due to the acoustic resonance of the tube and the absorption enhancement of the integrating sphere relatively to a non-resonant single pass cell. It is observed that the background absorption signals are highly attenuated due to the thermal conduction and diffusion effects in the polytetrafluoroethylene cell walls. This demonstrates that careful choice of cell wall materials can be highly beneficial to the sensitivity of the PA sensor. These properties makes the sensor suitable for various practical sensor applications in the ultraviolet (UV) to the near infrared (NIR) wavelength region, including climate, environmental and industrial monitoring.

The optical properties of graphene are made unique by the linear band structure and the vanishing density of states at the Dirac point. It has been proposed that even in the absence of a bandgap, a relaxation bottleneck at the Dirac point may allow for population inversion and lasing at arbitrarily long wavelengths. Furthermore, efficient carrier multiplication by impact ionization has been discussed in the context of light harvesting applications. However, all of these effects are difficult to test quantitatively by measuring the transient optical properties alone, as these only indirectly reflect the energy- and momentum-dependent carrier distributions. Here, we use time- and angle-resolved photoemission spectroscopy with femtosecond extreme-ultraviolet pulses to directly probe the non-equilibrium response of Dirac electrons near the K-point of the Brillouin zone. In lightly hole-doped epitaxial graphene samples, we explore excitation in the mid- and near-infrared, both below and above the minimum photon energy for direct interband transitions. Whereas excitation in the mid-infrared results only in heating of the equilibrium carrier distribution, interband excitations give rise to population inversion, suggesting that terahertz lasing may be possible. However, in neither excitation regime do we find any indication of carrier multiplication, questioning the applicability of graphene for light harvesting.

The purpose of this study is to determine the pre- and postactivity stretching practices of Division I, II, and III track and field throws programs. A 33-item survey instrument was developed to collect data regarding the warm-up and flexibility practices at the National Collegiate Athletic Association (NCAA) Division I (n = 320), Division II (n = 175), and Division III (n = 275) universities. A total of 135 surveys were completed for a 17.5% return rate, and although the response rate was generally low, it did mirror the distribution percentages of the 3 divisions. Significant differences were found for the level of United States Track and Field (USATF) certification and the use of static stretching (SS) between throws (χ = 6.333, p = 0.048). Significance was also found for the USATF certification level and athletic trainer (AT) assistance in performing SS (χ = 13.598, p = 0.01). Significant differences were also found for the NCAA division levels and the use of soft tissue mobilization (χ = 5.913, p = 0.026). Although research supports dynamic warm-up/stretching over other forms of preactivity protocols, it seems that some track-and-field throws coaches are reluctant to completely discontinue preactivity SS. The results of this study suggest that it is necessary for track and field throws coaches to reevaluate their own practices, perhaps better aligning them with current research findings.

This study sought to determine the effectiveness of coach certification courses in promoting proper preactivity and postactivity stretching practices in National Collegiate Athletic Association (NCAA) Division I, II, and III crosscountry programs. Distribution of questionnaires to 770 NCAA Division I, Division II, and Division III programs in the U.S.A. resulted in 111 coaches (88 [78.2%] men and 25 [21.8%] women) participating. Chi-square analyses revealed that noncertified coaches reported significantly greater (χ² = 21.582, p = 0.0174) usage of static stretching alone as their preactivity modality (18.9%, n = 9) vs. their certified counterparts (1.8%, n = 1). In addition, certified coaches reported a higher usage of dynamic flexibility only during the preactivity period (47.4%, n = 27) vs. their noncertified peers (32.4%, n = 16). Coaches were also asked if they allowed for static stretching between interval work and events in track and field, and a significantly higher percentage (χ² = 11.948, p = 0.0177) of noncertified coaches (45.5%, n = 23) reported allowing the athletes to perform static stretches between intervals at practice than certified peers (37.9%, n = 22). These significant differences help demonstrate that coaching certification courses are an effective tool for communicating current information about stretching practices. However, the results also revealed that there are still many certified coaches who are not implementing best practices in preactivity routines.

The rapid growth and expanding use of high school strength and conditioning facilities (SCFs) creates a need to research and better understand these vital facilities. This study was designed to examine SCFs at the high school level including facility size, equipment, leadership/staffing, and safety. A 70-item online survey instrument, developed with expert input from certified strength professionals, was used to collect data regarding the SCFs in high schools throughout a midwestern state, and was distributed via email to a total of 390 high school athletic directors. Survey respondents (n = 108) all reported the presence of SCFs with 95.4% indicating a dedicated SCF space. A strong positive correlation (r = 0.610, p ≤ 0.001) was determined between the variables of SCF size in square feet and school size measured by total enrollment. Analysis of variance and χ² analyses revealed significant differences in equipment, facility size, and safety factors based on the categorical variables of school size and the presence of certified strength and conditioning specialist (CSCS) leadership. It appears the CSCS's application of their scientific knowledge goes beyond training athletes for the goal of improving athletic performance to actually influence the SCF itself. Athletic administrators at the high school level need to recognize the impact CSCS program leadership can have on the overall quality of the strength and conditioning program and facility.

We use time- and angle-resolved photoemission spectroscopy with sub-30-fs extreme-ultraviolet pulses to map the time- and momentum-dependent electronic structure of photoexcited 1T-TaS(2). This compound is a two-dimensional Mott insulator with charge-density wave ordering. Charge order, evidenced by splitting between occupied subbands at the Brillouin zone boundary, melts well before the lattice responds. This challenges the view of a charge-density wave caused by electron-phonon coupling and Fermi-surface nesting alone, and suggests that electronic correlations play a key role in driving charge order., (© 2011 American Physical Society)

Based on previous water immersion results, we tested the hypothesis that the acute 0-G-induced increase in cardiac output (CO) is primarily caused by redistribution of blood from the vasculature above the legs to the cardiopulmonary circulation. In seated subjects (n = 8), 20 s of 0 G induced by parabolic flight increased CO by 1.7 ± 0.4 l/min (P < 0.001). This increase was diminished to 0.8 ± 0.4 l/min (P = 0.028), when venous return from the legs was prevented by bilateral venous thigh-cuff inflation (CI) of 60 mmHg. Because the increase in stroke volume during 0 G was unaffected by CI, the lesser increase in CO during 0 G + CI was entirely caused by a lower heart rate (HR). Thus blood from vascular beds above the legs in seated subjects can alone account for some 50% of the increase in CO during acute 0 G. The remaining increase in CO is caused by a higher HR, of which the origin of blood is unresolved. In supine subjects, CO increased from 7.1 ± 0.7 to 7.9 ± 0.8 l/min (P = 0.037) when entering 0 G, which was solely caused by an increase in HR, because stroke volume was unaffected. In conclusion, blood originating from vascular beds above the legs can alone account for one-half of the increase in CO during acute 0 G in seated humans. A Bainbridge-like reflex could be the mechanism for the HR-induced increase in CO during 0 G in particular in supine subjects.

A 32 mW fiber laser is stabilized to the (13)C(2)H(2) P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. The short-term shot-noise limited fractional frequency instability is 5.0 × 10(-13)(τ/s)-½ for averaging times τ up to about 100 s. The relative lock-point repeatability over 2½ month is 4.3 × 10(-13) corresponding to 83 Hz. The simple setup includes a 21 cm long gas cell, but it does not require an enhancement cavity or external modulators. The spectroscopic lineshape is analyzed with respect to optical power and acetylene pressure. Narrow linewidths of 300 kHz FWHM are observed with a signal to noise ratio of 35 dB in a 9 Hz bandwidth.

The transient optical conductivity of photoexcited 1T-TaS2 is determined over a three-order-of-magnitude frequency range. Prompt collapse and recovery of the Mott gap is observed. However, we find important differences between this transient metallic state and that seen across the thermally driven insulator-metal transition. Suppressed low-frequency conductivity, Fano phonon line shapes, and a midinfrared absorption band point to polaronic transport. This is explained by noting that the photoinduced metallic state of 1T-TaS2 is one in which the Mott gap is melted but the lattice retains its low-temperature symmetry, a regime only accessible by photodoping.

The transmission properties of five types of hollow-core photonic bandgap fibers (HC-PBFs) are characterized in the telecom wavelength range around 1.5 microm. The variations in optical transmission are measured as a function of laser frequency over a 2 GHz scan range as well as a function of time over several hours. The influence of these variations on spectroscopy of molecules in a HC-PBF is simulated.

We have demonstrated microwave optical double resonance spectroscopy of the nu(1) + nu(3) and nu(1) + 2nu(4) bands of ammonia in a hollow-core photonic bandgap fiber. Signal strength and lineshapes are analyzed. Spectroscopic assignments of previously assigned lines and previously proposed assignments have been confirmed and new assignments have been made. Several microwave transitions in the excited vibrational states have been measured for the first time.

We have demonstrated frequency modulation saturation spectroscopy of the nu(1) +nu(3) band of ammonia in hollow-core photonic bandgap fibers (HC-PBFs). Previously blended lines have been resolved and the corresponding molecular transitions assigned. Cross-over resonances are observed between transitions that do not share a common level. We have measured the pressure dependence of the line shape and determined the collisional self-broadening coefficients for ammonia. The many absorption lines of ammonia in the 1.5 microm wavelength region are potential frequency references lines for optical communication as well as candidates for spectroscopic trace gas monitoring.

We report on saturated absorption in a hollow-core photonic band-gap fiber filled with 12C2H2 molecules. We find that slow molecules provide a major contribution to the signal in the limit of low optical power and low pressure where the signal deviates significantly from the usual Lorentzian line shape. In particular, we observe a linewidth reduction of about 3 times as compared to the transit-time limited linewidth.

Pitch canker, caused by Gibberella circinata, is a disease affecting pines throughout the world. Although the pathogen is capable of sexual reproduction, natural populations are often comprised of very few vegetative compatibility groups (VCGs), which implies a predominance of asexual reproduction. However, even where outcrossing occurs, a population could have limited VCG diversity due to a low level of polymorphism at the loci governing vegetative compatibility (=vic loci). To determine whether this was the case for the California population of G. circinata, inter-fertile strains were crossed under laboratory conditions. Progeny of this cross included a minimum of 29 VCGs, which was consistent with segregation of vic alleles at five loci. Only two of these VCGs were known to occur naturally in California. Three VCGs accounted for 32.4% of the progeny but 0% of the California population. Overall, the results support the conclusion that outcrossing has been rare or absent in the California population of G. circinata.

Nowadays the transmission powers in optical telecommunication networks are often hundreds of milliwatts. Such high power levels are known to cause several nonlinear effects, thus affecting data transfer. Therefore, accurate measurements of such high power levels are required. The general issues that are to be considered when one is realizing a scale for high fiber optic power are discussed. The scales of the national standards laboratories in Finland, Sweden, and Denmark are described, and the results of a trilateral comparison of these scales are presented. The power range of the comparison was 1-200 mW. The results show that the stated measurement uncertainties of the three laboratories (1.3%-2.9%, k = 2) are applicable over this power range.

Optical spectrum analyzers are of increasing importance in fiber-optic laboratories. To perform reliable measurements with these devices, one must calibrate them with respect to wavelength, resolution bandwidth, power, etc. and know the temperature dependence of such calibrations. We have constructed a temperature-controlled chamber that can contain a spectrum analyzer and that can be regulated to within +/-0.1 degrees C. We report the temperature dependence of wavelength calibration and compare the various calibration results performed under temperature control with those previously obtained at ambient nonregulated temperature. For these studies we have used a compact calibration artifact based on absorption spectroscopy of acetylene.