2,585 research outputs found
Coherent resonant interactions and slow light with molecules confined in photonic band-gap fibers
We investigate resonant nonlinear optical interactions and demonstrate
induced transparency in acetylene molecules in a hollow-core photonic band-gap
fiber at 1.5m. The induced spectral transmission window is used to
demonstrate slow-light effects, and we show that the observed broadening of the
spectral features is due to collisions of the molecules with the inner walls of
the fiber core. Our results illustrate that such fibers can be used to
facilitate strong coherent light-matter interactions even when the optical
response of the individual molecules is weak.Comment: 5 pages, 4 figure
Documentation of Apollo 15 samples
A catalog is presented of the documentation of Apollo 15 samples using photographs and verbal descriptions returned from the lunar surface. Almost all of the Apollo 15 samples were correlated with lunar surface photographs, descriptions, and traverse locations. Where possible, the lunar orientations of rock samples were reconstructed in the lunar receiving laboratory, using a collimated light source to reproduce illumination and shadow characteristics of the same samples shown in lunar photographs. In several cases, samples were not recognized in lunar surface photographs, and their approximate locations are known only by association with numbered sample bags used during their collection. Tables, photographs, and maps included in this report are designed to aid in the understanding of the lunar setting of the Apollo 15 samples
Athlete Perceptions of Flavored, Menthol-enhanced Energy Gels Ingested Prior to Running in the Heat
Thermal perception during exercise is known to influence endurance performance and the onset of fatigue. L-menthol, an organic compound derived from peppermint, evokes a cooling sensation through its action on TRPM8 channels which also respond to cold stimuli. Recent work identified that the internal application of menthol-enhanced fluids can be ergogenic during exercise in the heat. Hence, the addition of menthol to energy gels may be practical and beneficial for athletes. PURPOSE: To determine athlete acceptability and preferences for flavored energy gels with different menthol concentrations. METHODS: With a randomized, crossover, and double-blind placebo-controlled design, 27 endurance athletes (34.8Ā±6.7 y, BMI: 21.7Ā±1.6 kgĀ·m-2, 9 female) ingested an energy gel with a menthol additive at relative concentrations: low (0.1%), medium-low (0.3%), medium-high (0.5%), high (0.7%), or a non-menthol, flavor-matched placebo (CON), on separate days before outdoor running sessions. Athletes rated the gels for cooling sensation, irritation (tingling/burning), flavor, and overall experience on 100-point sensory and hedonic labeled magnitude scales. The duration of any cooling sensation was also reported. Repeated measures ANOVAs with a Bonferroni adjustment for pairwise comparisons were used to determine differences. RESULTS: All menthol gels successfully delivered a greater cooling sensation compared to CON (7.4Ā±8.1 AU) with a significantly greater response for 0.7% (59.9Ā±20.5 AU) and 0.5% (57.7Ā±21.8 AU), compared to all others, which were both rated āmoderate-strongā for intensity. Irritation intensity was higher for all menthol gels compared to CON (3.4Ā±7.2 AU), and for 0.7% compared to 0.1% (31.1Ā±31.0 vs 16.3Ā±21.0 AU, p=0.041), with none reported higher than a āmild-moderateā intensity. The menthol gels delivered a significantly longer cooling duration (range: 12.3-19.6 min) compared to CON (2.2Ā±4.8 min) with no significant difference between menthol gels. Ratings of overall experience and flavor were not different between gels (p\u3e.05). CONCLUSION: A flavored energy gel with the addition of menthol at 0.1-0.7% provides a cooling sensation for athletes when ingested before exercise. The 0.5% concentration is recommended to maximize the cooling sensation of the gel whilst minimizing irritation
Ricci-flat supertwistor spaces
We show that supertwistor spaces constructed as a Kahler quotient of a
hyperkahler cone (HKC) with equal numbers of bosonic and fermionic coordinates
are Ricci-flat, and hence, Calabi-Yau. We study deformations of the
supertwistor space induced from deformations of the HKC. We also discuss
general infinitesimal deformations that preserve Ricci-flatness.Comment: 13 pages, references and comments adde
Preliminary report on the geology and field petrology at the Apollo 15 landing site
Apollo 15 mission and manned geologic exploration of lunar landing site - map
Athlete perceptions of flavored, menthol-enhanced energy gels ingested prior to endurance exercise in the heat
Background
L-menthol evokes a cooling sensation by activating cold sensing cation channels. Menthol-enhanced fluids can be ergogenic during exercise in the heat by improving thermal perception; hence, the addition of menthol to energy gels may benefit athletes. Previously, unflavored menthol gels were deemed acceptable at 0.1% concentration, but no research has been undertaken on menthol gels with additional flavoring. Therefore, we determined athlete perceptions of flavored energy gels with different menthol concentrations.
Methods
With a randomized, crossover, double-blind, placebo-controlled design, 27 athletes (34.8 Ā± 6.7 y, 9 females) ingested an energy gel with either 0.1%, 0.3%, 0.5%, or 0.7% menthol concentration, or a non-menthol, flavor-matched placebo (CON), on separate occasions before outdoor exercise. Gels were rated for cooling sensation, irritation, flavor, and overall experience on 100-point sensory and hedonic labeled magnitude scales. The duration of any cooling sensation was also reported.
Results
All menthol gels delivered a greater cooling sensation compared to CON (7.4 Ā± 8.1 AU) with a significantly greater response for 0.7% (59.9 Ā± 20.5 AU) and 0.5% (57.7 Ā± 21.8 AU), compared to all others. Irritation was higher for all menthol gels compared to CON (3.4 Ā± 7.2 AU) and for 0.7% compared to 0.1% (31.1 Ā± 31.0 vs. 16.3 Ā± 21.0 AU, p = 0.041), with none rated above a āmild-moderateā intensity. The menthol gels delivered a significantly longer cooling sensation duration (12.3-19.6 min) versus CON (2.2 Ā± 4.8 min) with no difference between menthol gels.
Conclusion
A flavored menthol energy gel at 0.1ā0.7% concentration provides a cooling sensation for athletes when ingested before exercise. The 0.5% concentration is recommended to maximize the cooling sensation whilst minimizing irritation
ACCEPTED MANUSCRIPT Bias in Markov Models of Disease
Abstract We examine bias in Markov models of diseases, including both chronic and infectious diseases. We consider two common types of Markov disease models: ones where disease progression changes by severity of disease, and ones where progression of disease changes in time or by age. We find sufficient conditions for bias to exist in models with aggregated transition probabilities when compared to models with state/time dependent transition probabilities. We also find that when aggregating data to compute transition probabilities, bias increases with the degree of data aggregation. We illustrate by examining bias in Markov models of Hepatitis C, Alzheimer's disease, and lung cancer using medical data and find that the bias is significant depending on the method used to aggregate the data. A key implication is that by not incorporating state/time dependent transition probabilities, studies that use Markov models of diseases may be significantly overestimating or underestimating disease progression. This could potentially result in incorrect recommendations from cost-effectiveness studies and incorrect disease burden forecasts
The effect of sound lure frequency and habitat type on male Aedes albopictus (Diptera: Culicidae) capture rates with the male Aedes sound trap
The global distribution of Aedes albopictus (Skuse) is rapidly expanding which has contributed to the emergence and re-emergence of dengue and chikungunya outbreaks. Improvements in vector surveillance are necessary to facilitate optimized, evidence-based vector control operations. Current trapping technology used to target Ae. albopictus and other Aedes species for vector surveillance are limited in both scale and scope, thus novel tools are required. Here, we evaluated the Male Aedes Sound Trap (MAST) for its capacity to sample male Ae. albopictus. Aims of this study were twofold: 1) to determine the most effective frequency for capturing male Ae. albopictus and 2) to investigate fine-scale variations in male Ae. albopictus abundance. MASTs which produced sound lure frequencies between 500 and 650 Hz captured significantly more male Ae. albopictus than those with sound lure frequencies set to 450 Hz. Further, the higher sound lure frequency of 700 Hz significantly reduced catches relative to 650 Hz. MASTs placed in woodland habitats captured significantly more male Ae. albopictus than MASTs placed near houses. These results provide baseline information for optimizing sound lure frequencies and placement of the MAST to sample male Ae. albopictus in remote areas
A menthol-enhanced ācoolingā energy gel does not influence laboratory time trial performance in trained runners
l-menthol (menthol) is an organic compound derived from peppermint which imparts a refreshing mint flavor and aroma to oral hygiene products, chewing gum, and topical analgesics. Menthol has been identified as a non-thermal sensory cooling strategy for athletes when ingested or mouth-rinsed during exercise in hot environments. Therefore, sports nutrition products delivering a controlled concentration of menthol could be beneficial for athletes exercising in the heat. We sought to test the performance and perceptual outcomes of a novel menthol energy gel during treadmill running in the heat (33 Ā°C, 49% RH). Fourteen trained runners (mean Ā± SD; age: 31 Ā± 6 years, VO2max: 56.5 Ā± 10.1 mLĀ·kgā1Ā·minā1, BMI: 23.2 Ā± 2.4 kg/m2; six female) participated in a randomized, crossover, double-blind, and placebo-controlled study. A menthol-enhanced energy gel (0.5% concentration; MEN) or flavor-matched placebo (PLA) was ingested 5 min before and again at 20 and 40 min of a 40 min treadmill exercise preload at 60% VO2max, followed by a 20 min self-paced time trial. The total distance, vertical distance, perceptual measures (thermal comfort, thermal sensation, rating of perceived exertion, and affect), and cognitive performance via computerized neurocognitive assessment were measured. No difference between 20 min self-paced time trial total distance (MEN: 4.22 Ā± 0.54 km, PLA: 4.22 Ā± 0.55 km, p = 0.867), vertical distance (MEN: 49.2 Ā± 24.6 m, PLA: 44.4 Ā± 11.4 m, p = 0.516), or any perceptual measures was observed (all p > 0.05). Cognitive performance was not different between the trials (all p > 0.05). These results suggest that a menthol energy gel is not superior to a non-menthol gel in terms of performance or perception during treadmill running in the heat. More research is needed to confirm whether these findings translate to ecologically valid settings, including outdoor exercise in ambient heat and during competition
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