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Recording systems that deal with Extra Low Frequency (ELF) data in the Schumann resonance (SR) range exhibit high sensitivity to external noise. In our effort to refine a time series by identifying and removing external disturbances from real data, we analyzed the effect of induced deliberate anthropogenic disturbances. The signals were recorded at the same time and same place by two separate systems with different designs and implementations. The main purpose of this experiment was to confirm that different systems in various observational sites could identify parasitic noises in the same way. The outcomes of this study may help ELF observers to discern intrinsic signals from artificial noise.

Cardiac function, skeletal (soleus) muscle oxidative metabolism, and the effects of exercise training were evaluated in a transgenic murine model (Tgαq*44) of chronic heart failure during the critical period between the occurrence of an impairment of cardiac function and the stage at which overt cardiac failure ensues (i.e., from 10 to 12 mo of age). Forty-eight Tgαq*44 mice and 43 wild-type FVB controls were randomly assigned to control groups and to groups undergoing 2 mo of intense exercise training (spontaneous running on an instrumented wheel). In mice evaluated at the beginning and at the end of training we determined: exercise performance (mean distance covered daily on the wheel); cardiac function in vivo (by magnetic resonance imaging); soleus mitochondrial respiration ex vivo (by high-resolution respirometry); muscle phenotype [myosin heavy chain (MHC) isoform content; citrate synthase (CS) activity]; and variables related to the energy status of muscle fibers [ratio of phosphorylated 5′-AMP-activated protein kinase (AMPK) to unphosphorylated AMPK] and mitochondrial biogenesis and function [peroxisome proliferative-activated receptor-γ coactivator-α (PGC-1α)]. In the untrained Tgαq*44 mice functional impairments of exercise performance, cardiac function, and soleus muscle mitochondrial respiration were observed. The impairment of mitochondrial respiration was related to the function of complex I of the respiratory chain, and it was not associated with differences in CS activity, MHC isoforms, p-AMPK/AMPK, and PGC-1α levels. Exercise training improved exercise performance and cardiac function, but it did not affect mitochondrial respiration, even in the presence of an increased percentage of type 1 MHC isoforms. Factors “upstream” of mitochondria were likely mainly responsible for the improved exercise performance. NEW & NOTEWORTHY Functional impairments in exercise performance, cardiac function, and soleus muscle mitochondrial respiration were observed in transgenic chronic heart failure mice, evaluated in the critical period between the occurrence of an impairment of cardiac function and the terminal stage of the disease. Exercise training improved exercise performance and cardiac function, but it did not affect the impaired mitochondrial respiration. Factors “upstream” of mitochondria, including an enhanced cardiovascular O2 delivery, were mainly responsible for the functional improvement.

From the second half of the 20th century there has been a rapid increase in electromagnetic radiation (EMR), generated in part by mobile phone networks. The aim of the study was to examine the effects of an electromagnetic field (EMF) with a frequency of 900 MHz on the hatchability of chicken embryos. The experimental groups were exposed to the electromagnetic field during the entire incubation period, for 10x4 minutes per day or 1x40 minutes per day. The results obtained indicate that an electromagnetic field with a frequency of 900 MHz, irrespective of the duration of a single exposure, significantly accelerates the process of pipping and hatching. In the experimental groups subjected to electromagnetic radiation the time between pipping and hatching was reduced. No influence of the 900 MHz EMF was observed on the hatching rate, number of developmental defects in the embryos, body weight, or the number of culled chicks.

Persistent negligence in the field of environmental protection in Poland as well as strong dependance of the energy sector on the fossil fuels have led to serious pollution of the air with particulate matter, which at high concentrations is capable of penetrating into the buildings. The aim of this study is to assess the impact of particulate airborne pollution on the concentration of particulate matter inside the antelope house in the Silesian Zoological Garden located within the Upper Silesia in Poland. The research was conducted from February to May in 2018. The records taken in the research period show that the concentration of PM10 exceeded the level of 50 µg/m3 outside the building during 26 days and 11 days when it comes to the concentration of particulate matter inside the antelope house. The quantity of particulate matter in the antelope house is strongly correlated with the concentration of the particles in the air. Despite fitting existing ventilation system with a filter that reduces the dust level by 60% during the highest level of smog, particulate matter concentration in the antelope house exceeded acceptable limit for PM10 more than twofold. Particle size-fraction analysis revealed that as much as 85% of the particles detected in the studied compartment constitute PM2.5.

Knowledge on body composition is important both in health and in disease, especially when considering chronic (i.e., growing, ageing, pregnancy) and interventional (nutrition, exercise, physical training) biological processes, as well as in predicting, preventing and managing such modern chronic diseases as sarcopenia, obesity, type 2 diabetes or metabolic syndrome. Therefore, in this chapter we present human body composition by taking advantage of widely accepted models, from the simplest 2-compartment model, which allows fat and fat-free body mass to be distinguished, up to a more complex, 6-compartment model, capable of distinguishing body fat, total body water, bone minerals, proteins, soft-tissue minerals, and glycogen. Moreover, in this chapter we provide equations that can be applied in laboratory and clinical practice to predict the main components of body composition, such as body water, skeletal muscles (SMs), body fat, and bone minerals. Special attention is given to the methods of evaluation of SM mass and its importance in health and disease.

The issue of air pollution by particulate matter (PM) concerns many places in the world. At the same time, many residents undertake physical activity (recreation, rehabilitation, sport) in the open air. Generally, the amount of dust concentration depends on both the place (center or periphery of the city) and the time of day. In the present study we describe the outcome of monitoring of the state of air pollution by particle matter (PM10) in the Kraków agglomeration area in order to show that it can provide information concerning air quality in the area where people practice varied kinds of sports in the open air. The measurements of PM10 have been made by a few stations with identical construction working as one network. The details of the air pollution monitoring system and its data quality verification have been described. The network stations made multipoint observations across the Kraków Metropolitan Area during the year 2017 in eight locations. The locations selected represent a diverse spectrum of terrain conditions in which the Kraków agglomeration community undertakes physical activity. For most months of 2017, the minimum monthly average 4-hour PM10 concentrations were recorded between 10–14 h, regardless of location, whereas the maximum was between 18–22. We also noticed a huge differences in the average monthly value of PM10 in some locations within the Kraków agglomeration—ranging between 4.9–339.0 µg m−3. This indicates that some regions of the city are more suitable for performance of physical activity in the open air than others. In conclusion, we postulate that a low-cost air pollution monitoring system is capable of providing valuable information concerning air quality in a given region, which seems to be of importance also to people who practice varied sports activities in the open air.

Exposure to artificial electromagnetic fields emitted mainly by mobile telephony has been steadily increasing with the development of modern technology. Haematological indices are among the most common indicators of the body’s physiological status. The aim of the study was to determine the effect of an 1800 MHz electromagnetic field emission on the blood picture of one-day-old domestic hen chicks. During the experiment, chick embryos were exposed to artificial electromagnetic fields throughout incubation for 13 ´ 2 min/day, 4 ´ 10 min/day and 1 ´ 40 min/day. After hatching, blood was collected from 10 one-day-old chicks from each group to determine: red blood cell count, haemoglobin concentration, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, white blood cell count, and leukocyte differential count. In addition, the heterophil/lymphocyte ratio was calculated. The present study is probably the first to show an increase in the red blood cell count, haemoglobin concentration, haematocrit, white blood cell count, segmented heterophils and the heterophil/lymphocyte ratio, and a decrease in lymphocyte percentage of embryos exposed to an 1800 MHz electromagnetic field. The observed changes may be indicative of the stress-inducing effect of EMF on living organisms.

Cardiac function, skeletal (soleus) muscle oxidative metabolism, and the effects of exercise training were evaluated in a transgenic murine model (Tgα

The level of artificial electromagnetic field (EMF) has steadily increased with the development of human civilization. The developing chicken embryo has been considered a good model to study the effects of EMF on living organisms. The aim of the study was to determine the effect of a 1800 MHz electromagnetic field during embryogenesis on the frequency of chick embryo malformations, morphometric parameters of the heart and liver and concentration of corticosterone in blood plasma, lipid and glycogen content in the liver of newly hatched chicks. A 1800 MHz EMF was found to shorten the duration of embryogenesis (earlier pipping and hatching of chicks) while having no effect on the quantity and quality of chicks and on increasing the incidence of embryo malformations. Exposure of chick embryos to EMF caused decreases in relative heart weight and right ventricle wall thickness. The pipping and hatching of chicks can be accelerated by stressful impact of EMF, which is confirmed by a significant increase in plasma corticosterone concentrations and decrease in fat and glycogen in the liver of chicks exposed during embryogenesis on the electromagnetic field with a frequency of 1800 MHz.

Everyday reports provided by meteorological services do not identify the size of the surface area covered by thunderstorms in the day. We discuss two methods of converting daily terrestrial observations of days with a thunderstorm into quantitative indices ( M and M v ) representing the surface area of thunderstorm occurrence on these days. The indices are first defined and tested using Monte Carlo simulation method before derivation from observational data. These indices that inform of how much thunderstorms spread over a selected region (e.g. country) during a day therefore provide different information than the frequency of thunderstorms. Using these indices we assess the daily area of thunderstorms occurrence (DASO) in Poland and Europe for each day between 1980 and 2010. We have found that the behaviour of large thunderstorm differs substantially between Poland and Europe. Whilst in Poland the frequency of these events has been growing by 4 days per decade, a reverse trend was observed in Europe, at 9 days per decade. We have also calculated that the mean number of thunderstorm days per year, recorded by the whole Poland weather network during the study period, is 127.

The paper discusses the frequency, persistence and succession sequence of six types of air mass during the period 1951-2010. The study, which relied on a calendar of air masses in southern Poland published by T. Niedźwiedź, concludes that there is no simple relationship between the persistence and the frequency of specific air masses in the region. The study found that there was a great variety in the persistence of specific types of air mass and that persistence depended more on the direction of air mass advection than on their frequency of occurrence. The study also failed to identify any strict overall rule of succession, as any air mass could follow after any other, but certain finer-grained patterns emerged. In winter and summer, arctic air (A) never followed directly after tropical air (T) or vice versa. Also, the most frequent succession sequence identified was from Polar maritime fresh air (mPf) to Polar maritime old and it accounted for the vast majority of successions from mPf into any other air mass (63 % annually and 76 % in summer).

Current human activity produces strong electromagnetic pollution. The power spectrum in the extremely low frequency (ELF, 3–3000 Hz) range is mainly polluted by anthropogenic narrow spectral lines at 16.66, 50, and 60 Hz and their harmonics. Meanwhile, signatures connected with natural phenomena appearing in the Earth’s atmosphere, ionosphere and magnetosphere are also observed in the same frequency range. This paper presents the amplitude behaviour of the anthropogenic lines in the years 2005–2014 based on the 10 years of activity of the Hylaty station situated in southeast Poland. The analysis includes, i.a., an assessment of the correctness of the choice of the Bieszczady mountains as a location for the installation of an ELF station for long-term geophysical and climatological studies.

In this study, we hypothesized that 5 weeks of cycling endurance training can decrease the magnitude of the non-proportional increase in oxygen uptake (V(O(2))) to power output relationship (V(O(2)) '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 Ca(2+)-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 (V(O(2)max)) by ∼7% (P = 0.002) despite there being no changes in V(O(2)max) (P = 0.49). This effect was due to a considerable reduction in the magnitude of the V(O(2)) 'excess' (P 0.05) were found after training. We conclude that the training-induced increase in power-generating capabilities at V(O(2)max) was due to attenuation of the V(O(2)) '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.

This work presents the results of a comparison between the global storm activity rate I RS and electric field intensity E 0 Z . The permanent analysis of the I RS may become an important tool for testing Global Electric Circuit models. I RS is determined by a new method that uses the background component of the first 7 Schumann resonances (SR). The rate calculations are based on ELF observations carried out in 2005 and 2006 in the observatory station “Hylaty” of the Jagiellonian University in the Eastern Carpathians (Kulak, A., Zieba, S., Micek, S., Nieckarz, Z., 2003. Solar variations in extremely low frequency propagation parameters: I. A two-dimensional telegraph equation (TDTE) model of ELF propagation and fundamental parameters of Schumann resonances, J. Geophys. Res., 108, 1270, doi:10.1029/2002JA009304). Diurnal runs of the I RS rate were compared with diurnal runs of E 0 Z amplitudes registered at the Earth's surface in the Geophysical Observatory of the Polish Academy of Sciences in Świder (Kubicki, M., 2005. Results of Atmospheric Electricity and Meteorological Observations, S. Kalinowski Geophysical Observatory at Świder 2004, Pub. Inst. Geophysics Polish Academy of Sciences, D-68 (383), Warszawa.). The days with the highest values of the correlation coefficient ( R ) between amplitudes of both observed parameters characterizing atmosphere electric activity are shown. The seasonal changes of R , I RS and E 0 Z are also presented.

Presented studies were conducted to assess the influence of alternating (AC) and/or static (DC) magnetic fields (MF) or combined with puromycin (PMC) on U937 cell line viability. The magnitude of DC MF was enclosed in the range (2 ÷ 6) mT. In case of AC MF, four frequencies were set: 12 Hz, 25 Hz, 35 Hz, 50 Hz and magnetic induction value was adjusted to 6.5(rms) mT. The reaction of samples exposed to MF and/or PMC was presented as cell viability coefficient S defined as a ratio of viable cells in the sample to viable cells in the relevant control sample, analyzed by flow cytometry. For PMC treated sample the percentage of viable cells decreased about factor 3. MF alone did not influence cell viability regardless of the type of exposure while simultaneous action of ACDC MF mode and PMC significantly influenced viability of U937 cells. The viability coefficient S was in the range of (0.13 ∓ 0.07 ÷ 0.64 ∓ 0.20) and exerted a non-linear relation with frequency of the AC MF component. The maximal lethal influence (S = 0.13 ∓ 0.07) was observed for DC MF = 6 mT and frequency of AC MF equal to 35 Hz. Observed bio-effects were confronted with the physical models assuming the Ca2+ ions transport disturbance and/or protein complexes dysfunction in cells due to MF action.

We compare the results of two methods of calculation of the charge moment change (CMC, also called the dipole moment change) of the cloud-to-ground lightning discharges. The first method uses multistation ground-based measurements of the E field change for the purpose of the lightning flash location and charge analysis. Our six stations, called the Local Lightning Detection Network (LLDN), were set up in the Warsaw region. The second method is based on measurements of the horizontal magnetic field component of electromagnetic waves generated by atmospheric discharges in the ELF (extremely low frequency) range. Our ELF station is equipped with two magnetic antennas, east-west and north-south and is located in a sparsely populated area of the Bieszczady Mountains in Poland (49.19°N, 22.55°E). We present and discuss the results obtained by both methods, focusing on the negative return stroke (RS) and the return stroke with continuing current (RS and CC) lightning discharges. Results show a good correlation between the CMC obtained by the two methods. For the negative RS and CC and RS the correlation coefficient is equal to +0.50 and +0.80, respectively.

Objective. To devise a system for geometry corrections in a rotating 3-dimensional sonographic system. Methods. A 3-dimensional sonographic imaging system based on a standard sonography machine was developed. The transducer mounted in a specially designed holder was rotated about its axis to acquire the spatial information. The most important postulate in rotating 3-dimensional systems is the assumption of parallelity between the rotation axis and the transducer axis. It allows the use of simple geometric relationships between 2-dimensional slices in a 3-dimensional reconstruction. The errors appearing in the 3-dimensional reconstruction when the axes are not parallel were investigated. Results. A simple correction method based on phantom measurements is proposed. The phantom contains a plane, which is inclined to the rotation axis. The analysis of 2-dimensional plane images allows the geometric corrections. The construction of the phantom is described, and the formulas used in the calculations are presented. The method was tested in computer simulations and in patient investigations. Conclusions. A complete method of the geometric investigations and corrections useful in 3-dimensional sonographic systems based on rotational geometry is proposed. Both the computer simulations and the phantom measurements confirmed the usefulness, precision, and simplicity of the proposed method.

We presented a novel approach to studies of the vascular grooves located on the inner surface of the cranial vault. A three-dimensional vision system that acquired the endocranial surface topography was used for this purpose. The acquired data were used to generate images showing the branching pattern of the middle meningeal artery. Fractal dimension was used to characterize and analyze branching pattern complexity. We discussed the usefulness of the latter method and indicated difficulties and potential errors connected to the fractal dimension application. The technique introduced for recording traits of the object surface appears to be helpful in anatomical study of morphological variation of dural vascularization. It may also be applicable in paleoneurological research based on analysis of the cranial remnants. Fractal dimension should be used carefully as a method sensitive to many aspects of data acquisition and processing.

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.

The aim of the study was to determine the effect of alternating electromagnetic field (EMF; 50 Hz frequency, 50 and 100 μT induction) on cardiac work of the chick embryo. Eggs from the experimental groups were exposed to EMF throughout incubation. During the experiment, heart rate (ballistocardiographic method), thyroxine (T4) and triiodothyronine (T3) concentrations, heart weight, ventricle wall thickness, and levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. The results show, for the first time, that the exposure of chick embryos to EMF augments the heart rate, especially from 17 days of incubation. The increased heart rate in the embryos exposed to EMF was associated with considerable increases in plasma T4 and T3 concentrations, which were recorded during the final stage of embryogenesis. The significant effect of the 100-μT field on heart weight and blood AST levels in the embryos suggests that EMF has a direct effect on the physiological function of cardiac muscle.

Spotless days (i.e., days when no sunspots are observed on the Sun) occur during the interval between the declining phase of the old sunspot cycle and the rising phase of the new sunspot cycle, being greatest in number and of longest continuous length near a new cycle minimum. In this paper, we introduce the concept of the longest spotless segment (LSS) and examine its statistical relation to selected characteristic points in the sunspot time series (STS), such as the occurrences of first spotless day and sunspot maximum. The analysis has revealed statistically significant relations that appear to be of predictive value. For example, for Cycle 24 the last spotless day during its rising phase should be about August 2012 ($\pm$ 9.1 months), the daily maximum sunspot number should be about 227 ($\pm$ 50; occurring about January 2014 $\pm$ 9.5 months), and the maximum Gaussian smoothed sunspot number should be about 87 ($\pm$ 25; occurring about July 2014). Using the Gaussian-filtered values, slightly earlier dates of August 2011 and March 2013 are indicated for the last spotless day and sunspot maximum for Cycle 24, respectively.

In this study, we hypothesized that 5 weeks of cycling endurance training can decrease the magnitude of the non-proportional increase in oxygen uptake (V(O(2))) to power output relationship (V(O(2)) '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 Ca(2+)-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 (V(O(2)max)) by ∼7% (P = 0.002) despite there being no changes in V(O(2)max) (P = 0.49). This effect was due to a considerable reduction in the magnitude of the V(O(2)) 'excess' (P0.05) above the LT. A decrease in plasma ammonia concentration was found during exercise after training (P0.05). 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 (P0.05) were found after training. We conclude that the training-induced increase in power-generating capabilities at V(O(2)max) was due to attenuation of the V(O(2)) '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.

[1] We present a new method of automatic detection of ELF impulses related to cloud-to-ground lightning at distances 1–2 Mm from a broadband ELF receiver and also we present a new numerical automated technique for calculating the lightning dipole moment. We have performed the detection for two known data sets of lightning flashes detected by the French lightning detection network Meteorage in southwest Europe over two 48 h periods 28–29 July and 6–7 September 2005. The number of flashes identified in the ELF data compared to the number of flashes detected by Meteorage reach 10–25% when little local activity close to the ELF station is present. The local thunderstorm activity worsens the detection of lightning from larger distances and the efficiency of identification of ELF impulses as lightning can decrease to a few percent. By combining the information on the location of the lightning flashes from Meteorage with the ELF data, lightning dipole moments can be calculated. Our results suggest the dipole moment is linearly correlated with the lightning peak current (p ≃ 7.5 Imax) but the dispersion of the dipole moment for a given peak current is significant. One of the reasons of such dispersion is the contribution of the lightning continuing current to the ELF signal.

Aim of the study is to determine a possible influence of alternating (AC) and static (DC) magnetic fields (MF) combined with chemical factors on U937 human lymphoid cell line viability, when exposed in vitro. U937 cells were cultivated at final density of 2.5 x 105 cells/ml. Culture probes were exposed to homogenous static (6 mT) MF alone or combined with perpendicularly oriented sinusoidal component (6.5 rms mT, 50 Hz) for 2.5 h, produced by the Helmholtz coils. Expositions were repeated (1-3) times with 24 h intervals. Part of cells was additionally treated with puromycin (PUR) at concentration 100 μg/ml simultaneously with MF exposition. Cell cultures were stained with Annexin V-APC for apoptosis and with 7- amino-actinomycin D for necrosis detection and examined with BD FACSCalibur flow cytometer. The results revealed difference between subpopulations of intact cells and these supplemented with PUR, exposed and unexposed to MF. The difference between viable cells percentage in a control and those treated with PUR was about 70%. MF exposition alone did not change cells viability. Combination of MF applied in different modes with chemical stimulation, provoked changes in the ratio of viable cells from 2 up to 4 times, in a comparison to only magnetically stimulated ones. Possibility of cells viability modulation, may play an important role in further cancer researches.

[1] Measurements of extremely low frequency (ELF) transients can be used to obtain model parameters and rates of the strong cloud-to-ground (CG) lightning discharges that generate them. In this study, we present an analytical description of a CG lightning discharge which takes into account both a return stroke and a continuing current. Using quasi-TEM (q-TEM) solutions for the Earth-ionosphere waveguide for distances within the near zone we show that the ELF spectrum of transients strongly depends on the percentage contribution of the continuing current to the discharge process. It is supposed that during typical observational conditions the only parameter of an ELF transient that can be measured sufficiently accurately is the impulse amplitude. In relation to the observational conditions the consequences of the calibration of ELF receivers on the measured ELF impulse amplitude are discussed, particularly the role of antialias filters. It is demonstrated that measurements of the ELF transient amplitude at a known distance to the source allows the total dipole moment of the discharge to be calculated and allows contributions of the return stroke and continuing current to this process to be estimated. Furthermore, some techniques of the signal spectral filtration that enable independent measurements of the return and continuing phase of the discharge are discussed.

Time variations of lightning activity in the three main tropical thunderstorm centers located in the Maritime Continent (Pakistan, India, Southeast Asia, Indonesia, and Australia), Africa, and the Americas are analyzed using a lightning activity index IRS, which is calculated from the resonances of magnetic field in the extremely low frequency range—the Schumann resonances—which were observed at Hylaty station (Poland) in the time interval July 2005–May 2006. Power spectrum analysis of the IRS series is carried out for this time interval. The annual and semiannual variations are shown in all of the series together with the following characteristic periodicities: 45 (Madden–Julian oscillation), 17.6, 13.5, and 4.8 days, seen mainly in the series describing the lightning activity of the Maritime Continent. In addition, maps of the dynamical power spectrum are constructed. They present variability both in the values of characteristic periods 26–30, 17–22, 12–14, 9–10, and 5–7 days and in their duration. During the studied time interval, according to these indices, the African center was the most active, whereas the American and Maritime Continent centers showed a similar level of activity. The largest differences among the centers were observed in the summer months in the Northern Hemisphere.

We study the “local” distribution of lightning activity on the Earth calculated from Extremely Low Frequency (ELF) magnetic field variations. Lightning generates strong electromagnetic impulses recorded in the ELF band as short signal spikes. Using two perpendicular magnetic antennas at our Hylaty station, we calculate the azimuths of the sources of such spikes. These ELF data are compared with selected satellite measurements available on NASA and BADC web centres. For the winter period January 8 to 9, 2006, analysed in detail, a large cyclone was observed over the Mediterranean Sea (MS). The cyclone was created in the western part of the MS and then moved eastwards along the North coast of Africa. The absence of lightning activity nearer our station allowed us to compare the ELF measurements with observations of this cyclone made from the TRMM and Meteosat‐7 satellites, using Lightning Imaging Sensor observations and full Earth disk images, respectively. The analysis proves that ELF measurements can be used for on‐line monitoring of lightning activity in the vicinity of the measuring ELF station, with the radius of effective observations being more than 2000 km. This inexpensive method can easily be used in areas without other lightning monitoring systems, or it can supplement existing ones.

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.

[1] Asymmetric resonance curves are observed in various resonance systems occurring in nature. The reason for such a shape of the resonance curves is an interaction of the standing waves field in the resonator with the field of traveling waves which transmit energy from sources to the resonator. This behavior can be observed in strongly damped electromagnetic resonators. The ELF wave propagation inside the Earth-ionosphere cavity is a good example of the simultaneous occurrence of resonance and transmission phenomena. In this paper we show that the transmission field component depends on the attenuation rate of the Earth-ionosphere cavity and the observer-source distance. Besides, the resonance curve asymmetry causes an evident diurnal variability of the resonance frequencies. The superposition of the two components at any point of the resonator makes the analysis of the Schumann resonance (SR) difficult. Here we suggest a field decomposition method that allows separating the resonance component from the transmission one. Owing to the decomposition, having a single measurement of the E or B field, it is possible, independently of the observer position, to study the physical properties of the resonator as well as to determine the localization and the intensity of sources. The field decomposition permits defining new resonator parameters such as reduced resonance frequencies and reduced quality factors, independent of the observer position inside the cavity. We believe that the application of the decomposition method in the analysis of the ELF observations yields a possibility of improving the accuracy of the determination of both the distances and intensities of the sources exciting the Earth-ionosphere resonator, as well as its own parameters.

The primary purpose of the research presented is to study solar variations in extremely low frequency (ELF) propagation parameters using Schumann resonance (SR) data from our irregular observations carried out in the East Carpathian mountains. The natural electromagnetic ELF fields in the Earth-ionosphere cavity (the global resonator) are strongly dependent on its resonance and propagation properties as well as on the global thunderstorm activity. Thus a determination of the global resonator parameters from Schumann resonances needs information about such signal properties, which depend only on physical conditions of the Earth-ionosphere cavity. To seek such signal properties, we consider the two-dimensional telegraph equation (TDTE) approach for describing propagation of ELF electromagnetic waves in a two-dimensional spherical transmission line model of the Earth-ionosphere cavity. We have set up a model consisting of a network of finite, homogeneous, one-dimensional transmission lines covering the sphere; with the square root dependence of the attenuation rate from frequency as a sufficient model for the study of the solar influence on global properties of the Earth-ionosphere cavity. Using this model, we have constructed useful formulae and algorithms connecting the observed parameters of Schumann resonances with the attenuation rate. This enables us to study the solar influence on the attenuation rate from diurnal observations of the NS-magnetic component of the ELF field measured at one station. As the measurements were carried out during both the minimum and the maximum of the solar cycle 23, we present in the work of Kuequation imageak et al. [2003] evidence for a change in the ELF attenuation rate in the Earth-ionosphere cavity with solar activity.

[1] Observations of resonant electromagnetic fields caused by global lightning activity are employed in determining the averaged parameters of the lower ionosphere. Using the two-dimensional telegraph equation (TDTE) transmission line model described by Kuak et al. [2003], we have computed the attenuation rate of the Earth-ionosphere waveguide from diurnal observations of the N-S magnetic component of the ELF field performed irregularly for 6 years in the East Carpathian mountains. As the measurements were carried out during both the minimum and the maximum of the solar cycle 23 we present how solar activity influence the first Schumann resonance frequency and the attenuation rate. The analysis of all the data indicates that the first Schumann resonance frequency increases from 7.75 Hz at solar minimum to about 7.95 Hz at solar maximum while the global mean attenuation rate α at 8 Hz varies from 0.31 dB/Mm at minimum to about 0.26 dB/Mm at maximum.

Solar activity slowly and irregularly decreases from the first spotless day (FSD) in the declining phase of the old sunspot cycle and systematically, but also in an irregular way, increases to the new cycle maximum after the last spotless day (LSD). The time interval between the first and the last spotless day can be called the passive interval (PI), while the time interval from the last spotless day to the first one after the new cycle maximum is the related active interval (AI). Minima of solar cycles are inside PIs, while maxima are inside AIs. In this article, we study the properties of passive and active intervals to determine the relation between them. We have found that some properties of PIs, and related AIs, differ significantly between two group of solar cycles; this has allowed us to classify Cycles 8 – 15 as passive cycles, and Cycles 17 – 23 as active ones. We conclude that the solar activity in the PI declining phase (a descending phase of the previous cycle) determines the strength of the approaching maximum in the case of active cycles, while the activity of the PI rising phase (a phase of the ongoing cycle early growth) determines the strength of passive cycles. This can have implications for solar dynamo models. Our approach indicates the important role of solar activity during the declining and the rising phases of the solar-cycle minimum.

It has been repeatedly shown that regular aerobic exercise exerts beneficial effects on incidence and progression of cancer. However, the data regarding effects of exercise on metastatic dissemination remain conflicting. Therefore, in the present study the possible preventive effects of voluntary wheel running on primary tumor growth and metastases formation in the model of spontaneous pulmonary metastasis were analyzed after orthotopic injection of 4T1 breast cancer cells into mammary fat pads of female Balb/C mice. This study identified that in the mice injected with 4T1 breast cancer cells and running on the wheels (4T1 ex) the volume and size of the primary tumor were not affected, but the number of secondary nodules formed in the lungs was significantly increased compared to their sedentary counterparts (4T1 sed). This effect was associated with decreased NO production in the isolated aorta of exercising mice (4T1 ex), suggesting deterioration of endothelial function that was associated with lower platelet count without their overactivation. This was evidenced by comparable selectin P, active GPIIb/IIIa expression, fibrinogen and vWF binding on the platelet surface. In conclusion, voluntary wheel running appeared to impair, rather than improve endothelial function, and to promote, but not decrease metastasis in the murine orthotopic model of metastatic breast cancer. These results call for revising the notion of the persistent beneficial effects of voluntary exercise on breast cancer progression, though further studies are needed to elucidate mechanisms involved in pro-metastatic effects of voluntary exercise.

The study of air circulation variability is important for a better understanding of river runoff. Research resented in this paper describes an attempt to find a link between air circulation on a large regional scale, and hydrological extremes of Carpathian river discharges in warm and cold seasons. The relationship between the North Atlantic Oscillation in winter, the Scandinavian baric system, and maximum and minimum river discharges was investigated over the period 1951-2000. Multiple correlation analysis was used. Some interesting relationships were found and multiple correlation formulae were developed for a few Carpathian basins. They may be used for hydrological forecasts of Carpathian extreme river discharges and they may allow the implementation of a warning system for extreme river events