Zaky A. Zaky, Hussein A. Amer, Bhuvneshwer Suthar
et al.
AbstractIn this paper, we theoretically propose a novel magnetic field-dependent sensor using omnidirectional magnetized cold plasma photonic crystal in one dimension for TE polarization. The structure consists of asymmetric two periodic arrays from magnetized cold plasma and sample cavity layer. Between the periodic arrays, a sample cavity is sandwiched between two quartz layers. The methodology of the proposed detector depends on the appearance of a sensitive defect mode. The results clear that the defect mode frequency depends significantly on the refractive index of the sample, and it is extremely sensitive to incident angle changes, applied magnetic field, the number density of electrons, and sample layer thickness. The optimized proposed sensor has high sensitivity of 15.14 GHz/RIU, quality-factor of 527.32, and figure of merit of 1066.20 RIU−1, where RIU means refractive index unit. So, the proposed sensor can aid in solving many challenges in chemical and environmental applications.
H-C NaÈ gerl of Innsbruck University in Austria and his colleagues have for the first time observed three-particle bound quantum states whose existence was predicted theoretically by V I Efimov in 1970 already [Yadernaya Fizika 12 1080 (1970)] Ð in a rare example of the complex three-body problem allowing an exact analytical solution. A universal set of low-energy bound states appears for a system of three identical particles with a strong enough resonant two-body interaction. Interestingly, because of the quantum-mechanical nature of this effect, three-particle states can even exist in the absence of two-particle bound states. The size of the threeparticle system is much less than the absolute scattering length jaj, and the three-particle interactions are universal in character and independent of precisely how two particles interact when close together. The researchers studied in experiment a degenerate gas of caesium atoms held in an optical dipole trap at temperatures between 10 and 250 nK. The scattering length was controlled by a Feshbach resonance and could be varied over a wide range by tuning the external magnetic field. For a 0. In this case, recombination losses are much lower and exhibit in their spectrum a recombination minimum due to the destructive interference of the three-particle system's quantum decay channels. The position of the minimum agrees well with theoretical predictions. For a > 0, Efimov states arise due to Feshbach resonances in collisions between single atoms and dimers and can be interpreted as a threebody generalization to the Feshbach resonance concept. Source: Nature 440 315 (2006) http://arxiv.org/abs/cond-mat/0512394
Abstract Dünnwald, T, Morawetz, D, Faulhaber, M, Gatterer, H, Birklbauer, C, Koller, A, Weiss, G, and Schobersberger, W. Supplemental O2 during recovery does not improve repeated maximal concentric-eccentric strength-endurance performance in hypoxia. J Strength Cond Res 36(11): 3065–3073, 2022—An alpine ski racing training session typically includes repeated bouts of maximal exercise at high altitude. We evaluated whether hyperoxic recovery between 5 sets of high-intensity strength-endurance exercises, which resembled ski racing activity and were performed in hypoxia, has beneficial effects on performance and acid-base status. In this randomized, single blinded crossover study, 15 highly skilled ski athletes (4 f/11 m; 29.7 ± 5.7 years) performed 5 90 seconds flywheel sets (S) in a normobaric hypoxic chamber (3,500 m). The flywheel sets were separated by 4 15-minute recovery periods. During recovery, subjects received either 100% O2 (hyperoxic setting [HS]) or hypoxic air (nonhyperoxic setting [NHS]; FiO2: 0.146). Performance outcomes (e.g., power output [PO], concentric peak power [Conpeak], and eccentric peak power [Eccpeak]) and physiological parameters (e.g., heart rate, blood gases, and blood lactate) were evaluated. Mean PO, Conpeak, and Eccpeak from S1 to S5 did not differ between settings (146.9 ± 45 W and 144.3 ± 44 W, 266.9 ± 80 W and 271.2 ± 78 W, and 271.0 ± 93 W and 274.1 ± 74 W for HS and NHS, respectively; p ≥ 0.05). SpO2, PaO2, and CaO2 were higher during recovery in HS than in NHS (p ≤ 0.001). Lactate levels were significantly lower in the last recovery phase in HS than in NHS (p = 0.016). Hyperoxic recovery has no impact on performance in a setting resembling alpine ski racing training. Positive effects on arterial oxygen content and cellular metabolism, as indicated by reduced blood lactate levels during recovery in the hyperoxic setting, seem to be insufficient to generate a direct effect on performance.
Crouse, SF, Tolson, H, Lytle, J, Johnson, KA, Martin, SE, Green, JS, Oliver, J, Carbuhn, A, Lambert, B, and Bramhall, JP. Predicting V[Combining Dot Above]O2max from treadmill performance in American-style football athletes. J Strength Cond Res 33(4): 1028-1034, 2019-Prediction equations are often used to estimate V[Combining Dot Above]O2max in the general population but are lacking for American-style football (ASF) athletes. We sought to develop a regression model to estimate V[Combining Dot Above]O2max from treadmill exercise time in ASF athletes and compare our football V[Combining Dot Above]O2max model with 2 published prediction equations (Foster et al., 1984, and Bruce, 1973). American-style football athletes (N = 472, age = 18 ± 1 year, height = 186.1 ± 8.2 cm, and body mass = 101.8 ± 20.4 kg) underwent treadmill exercise to voluntary exhaustion (Bruce protocol). Maximal exercise time was recorded in minutes (Tmin), and V[Combining Dot Above]O2max was simultaneously measured (M-V[Combining Dot Above]O2max, mlO2·kg·min) by an automated gas-analysis system. Athletes were then randomly divided into validation and cross-validation groups (n = 236). Linear regression yielded estimates of V[Combining Dot Above]O2max from Tmin as follows: validation V[Combining Dot Above]O2max = 4.012 × Tmin - 4.628 (r = 0.678, p 0.05), all athletes were combined to yield our final prediction equation: football V[Combining Dot Above]O2max = 4.017 × Tmin - 4.644 (r = 0.670, p < 0.001, and SEE = 4.11). Repeated-measures analysis of variance demonstrated significant differences (p < 0.001) in estimates of V[Combining Dot Above]O2max among Foster (44.1 ± 6.1), Bruce (47.1 ± 5.5), and our football (45.1 ± 5.8) equations. Foster and Bruce V[Combining Dot Above]O2max estimates were also significantly different from M-V[Combining Dot Above]O2max ((Equation is included in full-text article.)diff = -0.975 and 1.995, respectively, p < 0.001). V[Combining Dot Above]O2max of ASF athletes can be reasonably estimated by our football prediction equation using maximal treadmill time as the predictor.
de L. Corrêa, H, Ribeiro, HS, Maya, ÁTD, Neves, RP, de Moraes, MR, Lima, RM, Nóbrega, OT, and Ferreira, AP. Influence of the ACTN3 genotype and the exercise intensity on the respiratory exchange ratio and excess oxygen consumption after exercise. J Strength Cond Res XX(X): 000-000, 2018-This study aimed to assess the respiratory exchange ratio (RER) and excess postexercise oxygen consumption (EPOC) after high-intensity interval training and continuous moderate-intensity aerobic training in accordance with the ACTN3 genotype. A cross-sectional study with 30 physically active individuals who participated in 3 experimental sessions, as follows: a high-intensity interval aerobic exercise, for 3 minutes at 115% anaerobic threshold, with 90 seconds of passive recovery; a continuous moderate-intensity aerobic exercise at 85% anaerobic threshold; and a control session. Respiratory exchange ratio and V[Combining Dot Above]O2 were obtained through an indirect, calorimetry-based gas analysis method, using a breath-by-breath approach, assessed at baseline, during the trials, and at 1, 2, 3, and 4 hours after exercise. We found that lower postexercise RER values were observed only in subjects with the X allele, in both the high- and the moderate-intensity training protocols. Homozygous RR subjects showed no differences in postexercise RER compared with the scores at the control day. After both sessions of exercise, EPOC levels were higher compared with scores at the control day for 2 hours among X allele carriers, and only in the first hour among RR homozygous. Thus, the RER and EPOC presented different responses after moderate and intense exercise according to the ACTN3 genotype. Moreover, individuals with the X allele of the ACTN3 gene show a higher oxidation of fats in the postexercise period.
Abstract Chorley, A and Lamb, KL. The effects of a cycling warm-up including high-intensity heavy-resistance conditioning contractions on subsequent 4-km time trial performance. J Strength Cond Res 33(1): 57–65, 2019—Previous exercise has been shown to improve subsequent performance through different mechanisms. Sport-specific conditioning contractions can be used to exploit the “post-activation potentiation” (PAP) phenomenon to enhance performance although this has rarely been investigated in short endurance events. The aim of this study was to compare a cycling warm-up with PAP-inducing conditioning contractions (CW) with a moderate-intensity warm-up (MW) on performance and physiological outcomes of a 4-km time trial. Ten well-trained male endurance cyclists ( max 65.3 ± 5.6 ml·kg−1·min−1) performed two 4-km cycling time trials after a 5-minute recovery after a warm-up at 60% of max for 6.5 minutes (MW), and a warm-up with conditioning contractions (CW) consisting of 5 minutes at 60% of max then 3 × 10-second at 70% of peak power interspersed with a 30-second recovery. Blood lactate concentrations were measured before and after time trial. Expired gases were analyzed along with time, power output (PO), and peak forces over each 500 m split. After CW, mean completion time was reduced (1.7 ± 3.5 seconds p > 0.05), PO increased (5.1 ± 10.5 W p > 0.05) as did peak force per pedal stroke (5.7 ± 11 N p > 0.05) when compared with MW. increased (1.4 ± 1.6 ml·kg−1·min−1 p ⩽ 0.05) after CW, whereas respiratory exchange ratio (RER) decreased (0.05 ± 0.02 p ⩽ 0.05). Physiological and performance differences after CW were greatest over the first 1,500 m of the trials. The results suggest that a PAP-inducing warm-up alters kinetics and can lead to performance improvements in short endurance cycling but work and recovery durations should be optimized for each athlete.