The “slow component” of O₂uptake (V̇o₂) kinetics during constant-load heavy-intensity exercise is traditionally thought to derive from a progressive recruitment of muscle fibers. In this study, which represents a reanalysis of data taken from a previous study by our group (Grassi B, Hogan MC, Greenhaff PL, Hamann JJ, Kelley KM, Aschenbach WG, Constantin-Teodosiu D, Gladden LB. J Physiol 538: 195–207, 2002) we evaluated the presence of a slow component-like response in the isolated dog gastrocnemius in situ ( n = 6) during 4 min of contractions at ∼60–70% of peak V̇o₂. In this preparation all muscle fibers are maximally activated by electrical stimulation from the beginning of the contraction period, and no progressive recruitment of fibers is possible. Muscle V̇o₂was calculated as blood flow multiplied by arteriovenous O₂content difference. The muscle fatigued (force decreased by ∼20–25%) during contractions. Kinetics of adjustment were evaluated for 1) V̇o₂, uncorrected for force development; 2) V̇o₂normalized for peak force; 3) V̇o₂normalized for force-time integral. A slow component-like response, described in only one muscle out of six when uncorrected V̇o₂was considered, was observed in all muscles when V̇o₂/peak force and V̇o₂/force-time were considered. The amplitude of the slow component-like response, expressed as a fraction of the total response, was higher for V̇o₂/peak force (0.18 ± 0.06, means ± SE) and for V̇o₂/force-time (0.22 ± 0.05) compared with uncorrected V̇o₂(0.04 ± 0.04). A progressive recruitment of muscle fibers may not be necessary for the development of the slow component of V̇o₂kinetics, which may be caused by the metabolic factors that induce muscle fatigue and, as a consequence, reduce the efficiency of muscle contractions.

We present the Hylaty geophysical station, a high‐sensitivity and low‐noise facility for extremely low frequency (ELF, 0.03–300 Hz) electromagnetic field measurements, which enables a variety of geophysical and climatological research related to atmospheric, ionospheric, magnetospheric, and space weather physics. The first systematic observations of ELF electromagnetic fields at the Jagiellonian University were undertaken in 1994. At the beginning the measurements were carried out sporadically, during expeditions to sparsely populated areas of the Bieszczady Mountains in the southeast of Poland. In 2004, an automatic Hylaty ELF station was built there, in a very low electromagnetic noise environment, which enabled continuous recording of the magnetic field components of the ELF electromagnetic field in the frequency range below 60 Hz. In 2013, after 8 years of successful operation, the station was upgraded by extending its frequency range up to 300 Hz. In this paper we show the station's technical setup, and how it has changed over the years. We discuss the design of ELF equipment, including antennas, receivers, the time control circuit, and power supply, as well as antenna and receiver calibration. We also discuss the methodology we developed for observations of the Schumann resonance and wideband observations of ELF field pulses. We provide examples of various kinds of signals recorded at the station.

In this study, we hypothesized that 5 weeks of cycling endurance training can decrease the magnitude of the non‐proportional increase in oxygen uptake ( ) to power output relationship ( ‘excess’) at exercise intensities exceeding the lactate threshold (LT). Ten untrained, physically active men performed a bout of incremental cycling exercise until exhaustion before and after training. The mitochondrial DNA copy number, myosin heavy chain composition and content of uncoupling protein 3 and sarcoplasmic reticulum Ca²⁺‐ATPases (SERCAs) were analysed in muscle biopsies taken from vastus lateralis before and after training. The training resulted in an enhancement of the power‐generating capabilities at maximal oxygen uptake ( ) by ∼7% (P= 0.002) despite there being no changes in (P= 0.49). This effect was due to a considerable reduction in the magnitude of the ‘excess’ (P < 0.05) above the LT. A decrease in plasma ammonia concentration was found during exercise after training (P < 0.05). A downregulation of SERCA2 in vastus lateralis (P= 0.006) was observed after training. No changes in myosin heavy chain composition, selected electron transport chain proteins, uncoupling protein 3 or the mitochondrial DNA copy number (P > 0.05) were found after training. We conclude that the training‐induced increase in power‐generating capabilities at was due to attenuation of the ‘excess’ above the LT. This adaptive response seems to be related to the improvement of muscle metabolic stability, as judged by a lowering of plasma ammonia concentration. The enhancement of muscle metabolic stability after training could be caused by a decrease in ATP usage at a given power output owing to downregulation of SERCA2 pumps.

In this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station—the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1‐D thunderstorm lightning activity “maps” in absolute units C²m²/s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1° and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach.

Introduction: This study attempted to determine the effect of a 1800 MHz electromagnetic field (EMF) (only carrier frequency) on thyroxine (T4), triiodothyronine (T3) and corticosterone (CORT) concentrations in the blood plasma of chick embryos, and to investigate the effect of electromagnetic...