On the Temperature and Plasma Distribution of an Inductively Driven Xe-I2-Discharge

Inductively Coupled Plasma (ICP) discharges are part of intense research. Predicting different plasma parameters, like the distribution and temperature of the present species, is of great interest for many applications. Iodine- or halide-containing plasmas in particular have an important function, for example, in the development of mercury-free UV radiation sources. Therefore, a 2D simulation model of a xenon- and iodine-containing ICP was created by using the Finite Element Method (FEM) software COMSOL Multiphysics®. The included species and the used reactions are presented in this paper. To verify the simulation in relation to the plasma distribution, the results were compared with measurements from literature. The temperature of the lamp vessel was measured in relation to the temperature distribution and also compared with the results of the simulation. It could be shown that the simulation reproduces the plasma distribution with a maximal deviation of ≈6.5% to the measured values and that the temperature distribution in the examined area can be predicted with deviations of up to ≈24% for long vessel dimensions and ≈3% for shorter dimensions. However, despite the deviating absolute values, the general plasma behaviour is reproduced by the simulation. The simulation thus offers a fast and cost-effective method to estimate an effective geometrical range of iodine-containing ICPs.

Comparison and Performance Validation of Calculated and Established Anaerobic Lactate Thresholds in Running

Background and Objectives: This study aimed to compare the calculated running velocity at the anaerobic lactate threshold (cLTAn), determined by a mathematical model for metabolic simulation, with two established threshold concepts (onset of blood lactate accumulation (OBLA; 4 mmol∙L−1) and modified maximal deviation method (mDmax)). Additionally, all threshold concepts were correlated with performance in different endurance running events. Materials and Methods: Ten sub-elite runners performed a 30 s sprint test on a cycle ergometer adjusted to an isokinetic mode set to a cadence of 120 rpm to determine maximal lactate production rate (VLamax), and a graded exercise test on a treadmill to determine maximal oxygen uptake (VO2max). Running velocities at OBLA, mDmax, and cLTAn were then compared with each other, and further correlated with running performance over various distances (3000 m, 5000 m, and 10,000 m). Results: The mean difference in cLTAn was −0.13 ± 0.43 m∙s−1 and −0.32 ± 0.39 m∙s−1 compared to mDmax (p = 0.49) and OBLA (p < 0.01), respectively. cLTAn indicated moderate to good concordance with the established threshold concepts (mDmax: ICC = 0.87, OBLA: ICC = 0.74). In comparison with other threshold concepts, cLTAn exhibited comparable correlations with the assessed running performances (cLTAn: r = 0.61–0.76, mDmax: r = 0.69–0.79, OBLA: r = 0.56–0.69). Conclusion: Our data show that cLTAn can be applied for determining endurance performance during running. Due to the consideration of individual physiological profiles, cLTAn offers a physiologically justified approach to assess an athlete’s endurance performance.

Illustrating orientation changes of the insertion trajectory during cochlear implant electrode array insertion

Introduction: Recent investigations focused on the optimization of atraumatic cochlear implant surgery have highlighted the relevance of the electrode array (EA) insertion trajectory. This is particularly studied in the context of minimally-invasive “keyhole” and robotic-assisted approaches, e.g. to avoid injuring structures inside and outside the cochlea. However, little is known about the natural, manual movements and trajectory followed during the insertion process. The present work illustrates the orientation changes within the trajectory a surgeon follows during insertions of EAs into a human cadaveric cochlea. Methods: An EA insertion tool equipped with a gyroscope was developed in our laboratory. During the insertion trials, the gyroscope captures the tool’s spatial orientation. A human head specimen and a single EA were used to perform insertions into a cochlea. A cochlear implant surgeon performed all insertion trials. The recorded orientations were compared to the initial orientation upon cochlea entry to assess the surgeon’s range of motion by calculating the angle between orientation vectors. Results: Fifteen EA insertions were performed with a median maximal deviation from the initial orientation of 7.2° (5.3 -11.1°) across trials. The largest orientation changes were seen towards the last half of each insertion trial. A negative relationship between degree of axis change and number of insertion trial was observed (r = -0.5). Conclusion: Manual EA insertions into a cadaveric cochlea revealed an insertion trajectory with maximum orientation changes of approximately < 10° degrees. The observed trend on decreasing range of motion with increasing number of insertion trials may be attributed to surgeon’s familiarization with the insertion trajectory for this specific specimen but other contributing factors (e.g. EA softening) need to be further elucidated with several EAs. Future evaluations can help determine if this orientation change is influenced by surgeon expertise.

Predicting Lactate Threshold With Rate of Perceived Exertion in Young Competitive Male Swimmers

The purpose of this study was to verify the effectiveness of the rate of perceived exertion threshold (RPET) for predicting young competitive swimmers’ lactate threshold (LT) during incremental testing. We enrolled 13 male athletes ( M age = 16, SD = 0.6 years) in an incremental test protocol consisting of eight repetitions of a 100-meter crawl with 2-minute intervals between each repetition. We collected data for blood lactate concentration ([La]) and Borg scale rate of perceived exertion (RPE) at the end of each repetition. The results obtained were: M RPET = 4.98, SD = 1.12 arbitrary units (A.U.) and M lactate threshold = 4.24, SD = 1.12 mmol.L−1, with [La] and RPE identified by the maximal deviation (Dmax) method without a significant difference ( p > 0.05) and large correlations between DmaxLa and DmaxRPE at variables for time (r = 0.64), velocity (r = 0.67) and percentage of personal best time (PB) (r = 0.60). These results suggest that RPET is a good predictor of LT in young competitive swimmers.

On the properties of the classifier in case of maximal deviations of blood parameters from the norm

A mathematical model is described and implemented, intended for the numerical study of the ability of the statistical classification method to interpolate and extrapolate. The classifier developed by the authors is based on the polynomial-regression approach and has probabilistic estimates. It is used to assess the state of human health based on the parameters of laboratory analysis of peripheral blood. The blood base is considered with a maximal deviation from the norm.

Comparison of maximal lactate steady state with anaerobic threshold determined by various methods based on graded exercise test with 3-minute stages in elite cyclists

Background The maximal lactate steady state (MLSS) is defined as the highest workload that can be maintained for a longer period of time without continued blood lactate (LA) accumulation. MLSS is one of the physiological indicators of aerobic performance. However, determination of MLSS requires the performance of a series of constant-intensity tests during multiple laboratory visits. Therefore, attempts are made to determine MLSS indirectly by means of anaerobic threshold (AT) evaluated during a single graded exercise test (GXT) until volitional exhaustion. The aim of our study was to verify whether AT determined by maximal deviation (Dmax), modified maximal deviation (ModDmax), baseline LA concentration + 1 mmol/l (+ 1 mmol/l), individual anaerobic threshold (IAT), onset of blood lactate accumulation (OBLA4mmol/l) and V-slope methods based on GXT with 3-min stages provide valid estimates of MLSS in elite cyclists. Methods Twelve elite male cyclists (71.3 ± 3.6 ml/kg/min) completed GXT (the increase by 40 W every 3 min) to establish the AT (by Dmax, ModDmax, + 1 mmol/l, IAT, OBLA4mmol/l and V-slope methods). Next, a series of 30-min constant-load tests to determine MLSS was performed. Agreement between the MLSS and workload (WR) at AT was evaluated using the Bland–Altman method. Results The analysis revealed a very high (rs > 0.90, p < 0.001) correlation between WRMLSS and WRDmax and WRIAT. The other AT methods were highly (rs > 0.70) correlated with MLSS except for OBLA4mmol/l (rs = 0.67). The Bland-Altman analysis revealed the highest agreement with MLSS for the Dmax, IAT and + 1 mmol/l methods. Mean difference between WRMLSS and WRDmax, WRIAT and WR+1mmol/l was 1.7 ± 3.9 W, 4.3 ± 7.9 W and 6.7 ± 17.2 W, respectively. Furthermore, the WRDmax and WRIAT had the lowest limits of agreement with the WRMLSS. The ModDmax and OBLA4mmol/l methods overestimated MLSS by 31.7 ± 18.5 W and 43.3 ± 17.8 W, respectively. The V-slope method underestimated MLSS by 36.2 ± 10.9 W. Conclusions The AT determined by Dmax and IAT methods based on the cycling GXT with 3-min stages provides a high agreement with the MLSS in elite cyclists. Despite the high correlation with MLSS and low mean difference, the AT determined by + 1 mmol/l method may highly overestimate or underestimate MLSS in individual subjects. The individual MLSS cannot be properly estimated by V-slope, ModDmax and OBLA4mmol/l methods.

In-orbit Earth reflectance validation of TROPOMI on board the Sentinel-5 Precursor satellite

The goal of the study described in this paper is to determine the accuracy of the radiometric calibration of the TROPOMI instrument in flight, using its Earth radiance and solar irradiance measurements, from which the Earth reflectance is determined. The Earth reflectances are compared to radiative transfer calculations. We restrict ourselves to clear-sky observations as these are less difficult to model than observations containing clouds and/or aerosols. The limiting factor in the radiative transfer calculations is then the knowledge of the surface reflectance. We use OMI and SCIAMACHY surface Lambertian-equivalent reflectivity (LER) information to model the reflectivity of the Earth's surface. This Lambertian, nondirectional description of the surface reflection contribution results in a relatively large source of uncertainty in the calculations. These errors can be reduced significantly by filtering out geometries for which we know that surface LER is a poor approximation of the real surface reflectivity. This filtering is done by comparing the OMI/SCIAMACHY surface LER information to MODIS surface BRDF information. We report calibration accuracies and errors for 21 selected wavelength bands between 328 and 2314 nm, located in TROPOMI spectral bands 3–7. All wavelength bands show good linear response to the intensity of the radiation and negligible offset problems. Reflectances in spectral bands 5 and 6 (wavelength bands 670 to 772 nm) have good absolute agreement with the simulations, showing calibration errors on the order of 0.01 or 0 %–3 %. Trends over the mission lifetime, due to instrument degradation, are studied and found to be negligible at these wavelengths. Reflectances in bands 3 and 4 (wavelength bands 328 to 494 nm), on the other hand, are found to be affected by serious calibration errors, on the order of 0.004–0.02 and ranging between 6 % and 10 %, depending on the wavelength. The TROPOMI requirements (of 2 % maximal deviation) are not met in this case. Trends due to instrument degradation are also found, being strongest for the 328 nm wavelength band and almost absent for the 494 nm wavelength band. The validation results obtained for TROPOMI spectral band 7 show behaviour that we cannot fully explain. As a result, these results call for more research and different methods to study the calibration of the reflectance. It seems plausible, though, that the reflectance for this particular band is underestimated by about 6 %. A table is provided containing the final results for all 21 selected wavelength bands.

KiDS+VIKING-450: Improved cosmological parameter constraints from redshift calibration with self-organising maps

We present updated cosmological constraints for the KiDS+VIKING-450 cosmic shear data set (KV450) estimated through redshift distributions and photometric samples defined using self-organising maps (SOMs). Our fiducial analysis finds marginal posterior constraints of S8 ≡ σ8 Ωm/0.3 = 0.716−0.038+0.043, which are smaller but otherwise consistent with previous works that have applied this data set (|ΔS8| = 0.023). We analysed additional samples and redshift distributions set up in three ways: (1) by excluding certain spectroscopic surveys during redshift calibration; (2) by excluding lower-confidence spectroscopic redshifts in redshift calibration; and (3) by considering only those photometric sources which are jointly calibrated by at least three spectroscopic surveys. In all cases, the method utilised here has been proven to be robust: we find a maximal deviation from our fiducial analysis of |ΔS8| ≤ 0.011 for all samples defined and analysed using our SOM. To demonstrate the reduction in systematic biases found within our analysis, we highlight our results when performing redshift calibration without the DEEP2 spectroscopic data set. In this case, we find marginal posterior constraints of S8 = 0.707−0.042+0.046; this is a difference, with respect to the fiducial, that is both significantly smaller and in the opposite direction with regard to the equivalent shift from previous works. These results suggest that our improved cosmological parameter estimates are not sensitive to pathological misrepresentations of photometric sources by the spectroscopy used for direct redshift calibration and, therefore, that this systematic effect cannot be responsible for the observed difference between S8 estimates made with KV450 and Planck CMB probes.

In-orbit Earth reflectance validation of TROPOMI on board the Sentinel-5 Precursor satellite

The goal of the study described in this paper is to determine the accuracy of the radiometric calibration of the TROPOMI instrument in-flight, using its Earth radiance and solar irradiance measurements, from which the Earth reflectance is determined. The Earth reflectances are compared to radiative transfer calculations. We restrict ourselves to clear-sky observations as these are less difficult to model than observations containing clouds and/or aerosols. The limiting factor in the radiative transfer calculations is then the knowledge of the surface reflectance. We use OMI and SCIAMACHY surface Lambertian-equivalent reflectivity (LER) information to model the reflectivity of the Earth's surface. This Lambertian, non-directional description of the surface reflection contribution results in a relatively large source of uncertainty in the calculations. These errors can be reduced significantly by filtering out geometries for which we know that surface LER is a poor approximation of the real surface reflectivity. This filtering is done by comparing the OMI/SCIAMACHY surface LER information to MODIS surface BRDF information. We report calibration accuracies and errors for 21 selected wavelength bands between 328 and 2314 nm, located in TROPOMI spectral bands 3–7. All wavelength bands show good linear response to the intensity of the radiation and negligible offset problems. Reflectances in spectral bands 5 and 6 (wavelength bands 670 to 772 nm) have a good absolute agreement with the simulations, showing calibration errors on the order of 0.01 or 0–3 %. Trends over the mission lifetime, due to instrument degradation, are studied and found to be negligible at these wavelengths. Reflectances in bands 3 and 4 (wavelength bands 328 to 494 nm), on the other hand, are found to be affected by serious calibration errors, on the order of 0.004–0.02 and ranging between 6 % and 10 %, depending on the wavelength. The TROPOMI requirements (of 2 % maximal deviation) are not met in this case. Trends due to instrument degradation are also found, being strongest for the 328-nm wavelength band, and almost absent for the 494-nm wavelength band. The validation results obtained for TROPOMI spectral band 7 show behaviour that we cannot fully explain. As a result, these results call for more research and different methods to study the calibration of the reflectance. It seems plausible, though, that the reflectance for this particular band is underestimated by about 6 %. A table is provided containing the final results for all 21 selected wavelength bands.