Alena Fialová (ed.) ; redaktoři: Alena Fialová (próza), Petr Hruška (poezie), Lenka Jungmannová (drama)., Obsahuje bibliografie, bibliografické odkazy a rejstřík., and Anglické resumé
In this experiment we studied the effect of different pedalling rates during cycling at a constant power output (PO) 132±31 W (mean±S.D.), corresponding to 50 % V02 max, on the oxygen uptake and the magnitude of the slow component of V02 kinetics in humans. The PO corresponded to 50 % of V02 max, established during incremental cycling at a pedalling rate of 70 rev.min-1. Six healthy men aged 22.2 ±2.0 years with V02 max 3.89 ±0.92 l.min-1, performed on separate days constant PO cycling exercise lasting 6 min at pedalling rates 40, 60, 80, 100 and 120 rev.min-1, in random order. Antecubital blood samples for plasma lactate [La]pi and blood acid-base balance variables were taken at 1 min intervals. Oxygen uptake was determined breath-by-breath. The total net oxygen consumed throughout the 6 min cycling period at pedalling rates of 40, 60, 80, 100 and 120 rev.min-1 amounted to 7.727± 1.197, 7.705± 1.548, 8.679± 1.262, 9.945± 1.435 and 13.720± 1.862 1, respectively for each pedalling rate. The VO2 during the 6 min of cycling only rose slowly by increasing the pedalling rate in the range of 40-100 rev.min-1. This increase, was 0.142 1 per 20 rev.min-1 on the average. Plasma lactate concentration during the sixth minute of cycling changed little within this range of pedalling rates: the values were 1.83 ±0.70, 1.80 ± 0.48, 2.33 ±0.88 and 2.52 ±0.33 mmoLl-1. The values of [La]pi reached in the 6th minute of cycling were not significantly different from the pre-exercise levels. Blood pH was also not affected by the increase of pedalling rate in the range of 40-100 rev.min-1. However, an increase of pedalling rate from 100 to 120 rev.min-1 caused a sudden increase in the VO2 amounting to 0.747 1 per 20 rev.min-1, accompanied by a significant increase in [La]pj from 1.21 ±0.26 mmol.l-1 in pre-exercise conditions to 5.92±2.46 mmol.l-1 reached in the 6th minute of cycling (P<0.01). This was also accompanied by a significant drop of blood pH, from 7.355 ±0.039 in the pre-exercise period to 7.296 ± 0.060 in the 6th minute of cycling (P<0.01). The mechanical efficiency calculated on the basis of the net VO2 reached between the 4th and the 6th minute of cycling amounted to 26.6 ±2.7, 26.4±2.0, 23.4±3.4, 20.3 ±2.6 and 14.7±2.2 %, respectively for pedalling rates of 40, 60, 80,100 and 120 rev.min-1. No significant increase in the VO2 from the 3rd to the 6th min (representing the magnitude of the slow component of V02 kinetics) was observed at any of the pedalling rates (-0.022±0.056, -0.009±0.029, 0.012±0.073, 0.030±0.081 and 0.122±0.176 l.min-1 for pedalling rates of 40, 60, 80, 100 and 120 rev.min-1, respectively). Thus a significant increase in [La]pi and a decrease in blood pH do not play a major role in the mechanism(s) responsible for the slow component of VO2 kinetics in
humans.
In the present study, we investigated the effects of vagus nerve stimulation (VNS), a proposed treatment for patients with intractable epilepsy, on cardiac rhythm following seizures induced by pentylenetetrazole (PTZ) in Wistar rats. After a baselinerecording of electroencephalogram (EEG), electrocardiogram (ECG) and blood pressure (BP), rats in the first group received a single convulsive dose of PTZ (70 mg/kg) (Group 1). In the other
two groups, the Wistar rats were implanted with a cuff electrode on the left cervical vagus nerve. One day after surgery, rats in the second group were treated with VNS (Group 2), whereas rats in the third group were connected to the stimulator but did not receive VNS (Group 3). Ten minutes after VNS onset, 70 mg/kg dose of PTZ was injected. EEG, ECG and BP were continuously recorded during post-injection period. Seizure severity was scored behaviorally. Then, baseline, ictal and postictal periods were analyzed for cardiac rhythms, seizure severity and blood pressure variability. PTZ treatment induced tonic-clonic seizure activity in all animals of Group 1 and Group 3. In these groups a marked increase of mean arterial blood pressure (MABP) but a significant decrease in heart rate and PP interval fluctuations was observed at postictal period. However, in the VNS-treated group the seizure scores and cardiac parameter returned to the baseline level. Present results emphasize that VNS effectively reduces seizure severity and suppress the seizure-induced cardiac rhythm changes.
Two available subspecific names are used interchangeably for the Balkan lynx. In this contribution I demonstrate that the valid name is Lynx lynx balcanicus Bureš, 1941, and L. l. martinoi Mirić, 1978, is its junior synonym. The type locality of L. l. balcanicus is the Šara Mts. in the Republic of Macedonia. In reaching this conclusion, I refrain from infringing upon taxonomic judgment on whether or not the Balkan lynx is a subspecies in its own right. While addressing the Balkan lynx over the last decade, conservationists have largely ignored the older synonym balcanicus and used instead a junior synonym martinoi.
The aim of this study was to assess the performance of several approximation techniques for ionospheric total electron content (TEC) mapping. Approximation techniques based on data-fitting with local or general two-dimensional polynomials, local planes or distance-dependent interpolation were applied and tested. For the ionosphere modeling, dual-frequency GPS data from Polish GBAS system (ASG-EUPOS) were used, and TEC was estimated together with hardware delays from phasesmoothed pseudoranges. Next, grids of vertical TEC values with spatial resolution of 0.25 degrees in both latitude and longitude were generated using the evaluated approximation techniques. Subsequently the grids were used to create regional TEC maps with 5-minute temporal resolution, and also to create ionospheric delay corrections for GPS positioning. The quality of the resulting ionospheric maps was tested twofold, firstly by comparison to high-quality CODE global ionosphere maps (GIM), which were generated using data from about 150 GPS sites of the International GNSS Service (IGS). Secondly, by creating double-differenced ionospheric delay corrections and comparing them to reference values derived from the reference network data processing. For the correction tests, two perpendicular baselines directed North-South (N-S) and West-East (W-E) and reaching up to 100 km were selected. The approximation methods were analyzed with a special emphasis on the diverse ionospheric conditions. For the testing, a quiet ionosphere day of 20 March 2012 and an active ionosphere day of 9 March 2012 were selected. The results show that the regional models properly represent the changing ionosphere, with the best results provided by data-fitting into local functions., Anna Krypiak-Gregorczyk, Pawel Wielgosz, Dariusz Gosciewski and Jacek Paziewski., and Obsahuje bibliografii