Problems related to accuracy of tilt measurements realized during experimental studies of miniature tilt sensors (including MEMS devices) are minutely discussed. The measurements are performed by means of a custom computer controlled test rig, over the full range of pitch and roll. Accuracy of the test rig is determined in terms of uncertainty of the measurements involved. Ways of improving performance of the test rig are briefly introduced. Exemplary results of experimental works are presented. and Obsahuje seznam literatury
This paper presents development of a day ahead load forecasting (DALF) model for Turkish power system with an artificial neural network (ANN). Effects of special holidays including national and religious days, and hourly random load deviations observed in Turkish power system due to significant arc furnace loads are discussed. Performance of the ANN is investigated in the sense of both DALF performance - in terms of both daily mean absolute percentage error (MAPE) and hourly absolute percentage error (APE) - and hourly secondary reserves required to ensure supply/demand adequacy of the system. The most sensitive cities to DALF in terms of daily city temperature forecasts are ranked in order to reduce the input of the developed ANN and thereby to improve execution of the model. Candidate cities are determined based on both their placement with respect to climatic zones of the country and their contribution to the system load during peak hours. The results show that, although a well-trained ANN could provide very satisfactory daily MAPEs at non-special days, such as ~1%, the hourly absolute percentage errors (APE) could be significant due to large random load disturbances, which necessitate special attention during the day ahead allocation of hourly secondary reserves. By limiting the temperature data set with major cities, the input of ANN reduces significantly while not disturbing the MAPEs. Main contributions of the study are; addressing both benefits of the prioritizing the cities in a power system in the sense of their temperature forecast effects on the DALF performance and assessing the performance of DALF in the sense of necessary amount of secondary reserves in power systems which include significant random load deviations (e.g., large arc furnace loads).
Precise relative gravimeters achieve the internal precision about a few μGal 1, even in field conditions. Nevertheless this precision is in fact concerned with the instant of measurement and can not be confused with the accuracy of the gravity at the gravity station, which is influenced by other effects. The best approach of these two values is question of high-quality elimination of instrumental errors and time-variable disturbing effects affecting the relative gravity measurements., Martin Lederer., and Obsahuje bibliografii
Wire myograph is a device for the in vitro investigation of both, active and passive properties of arteries. Arteries from a variety of animal species, pathological states, and vascular beds were investigated using this method. We focus on the normalization procedure which is aimed to standardize experimental settings and, in part, to simulate physiological conditions. During normalization, it is determined the internal circumference of a vessel stretched to a tension that corresponds to the transmural pressure of 100 mm Hg (IC100). Once it is determined, the internal circumference is traditionally set to (0.9 ⋅ IC100). However, this constant 0.9, called also the normalization factor (NF), was experimentally determined for rat small mesenteric arteries only. Therefore, the aim of our work was to show the influence of different NFs on the passive tension and reactivity of both, rat femoral arteries (FA) an d the first branches of superior mesenteric arteries (MA). We found out that the maximal active wall tension of the FA was achieved at the NF value of 1.1, and that of the MA at 0.9. Considering the values of the active wall tension we suggest that higher reactivity and better signal-to- noise ratio in FA can be achieved when the NF is set at least to 1.0., P. Slezák, I. Waczulíková, P. Bališ, A. Púzserová., and Obsahuje bibliografii
Quasi-steady state assumptions are often used to simplify complex systems of ordinary differential equations in the modelling of biochemical processes. The simplified system is designed to have the same qualitative properties as the original system and to have a small number of variables. This enables to use the stability and bifurcation analysis to reveal a deeper structure in the dynamics of the original system. This contribution shows that introducing delays to quasi-steady state assumptions yields a simplified system that accurately agrees with the original system not only qualitatively but also quantitatively. We derive the proper size of the delays for a particular model of circadian rhythms and present numerical results showing the accuracy of this approach.
Despite significant advances in medical research, plastic surgeons still face a shortage of suitable patient tissues, and soft tissue reconstruction is no exception. In recent years, there has been a rapid boom in the use of acellular dermal matrix (ADM) in reconstructive and aesthetic surgery. ADM is incorporated into the surrounding tissue and gradually replaced by the host's collagen, thus promoting and supporting the healing process and reducing the formation of scar tissue. The main goal of this article is to provide a brief review of the current literature assessing the clinical applications of ADM across a broad spectrum of applications in plastic and reconstructive surgery.
Článek se zabývá přechylováním španělských životných substantiv. Na základě jazykového materiálu z korpusu CREA nejprve mapuje současný úzus a z něj pak vyvozuje některé tendence. Ukazuje se, že se v rodovém systému posilují flexivní rysy na úkor izolačních a že ubývá substantiv, která vyjadřují rod jinak než sufixálně, U některých substantiv během 25 let existence korpusu původně neexistující sufixálně přechýlená forma postupně zcela vytlačila ncpřechýlenou variantu. Tendence k sufixálnímu přechylování je posilována faktory vnějšími (vědomý tlak společnosti, kodifikovaná norma) i vnitřními: vyjadřování rodu determinanty je v systému považováno za nedostatečné, navíc v mnoha kontextech se determinant nevyskytuje nebo je příliš vzdálen od svého substantiva.
Considering the effects of alcohol on cardiac electrical behavior as well as the important role of the inward rectifier potassium current I K1 in arrhythmogenesis, this study was aimed at the effect of acetaldehyd e, the primary metabolite of ethanol, on I K1 in rat ventricular myocytes. Acetaldehyde induced a reversible inhibition of I K1 with IC 50 = 53.7± 7.7 μM at -110 mV; a significant inhibition was documented even at clinically -relevant concentrations (at 3 μM by 13.1 ±3.0 % ). The inhibition was voltage -independent at physiological voltages above - 90 mV. The I K1 changes under acetaldehyde may contribute to alcohol - induced alterations of cardiac electrophysiology, especially in individuals with a genetic defect of a ldehyde dehydrogenase where the acetaldehyde level may be elevated., M. Bébarová, P. Matejovič, M. Šimurdová, J. Šimurda., and Obsahuje bibliografii
Experiments were performed in C57BL/6J male mice to determine the effects of acetylcholinesterase (AChE) inhibitor pyridostigmine bromide (PB) and stress on cardiovascular function, structure, and apoptosis. Mice were studied for seven days under the following conditions: Controls (osmotic minipump with saline), PB (10 mg/kg/day, minipumps), shaker stress (45 stressors/day, minipump with saline) and PB+Stress combination. AChE activity was significantly reduced in all PB-treated mice. PB caused no changes in 24-h mean arterial pressure (MAP) or heart rate (HR). Stress
increased 24-h MAP on day 1 and 24-h HR on day 7 in both Stress and PB+Stress groups. A significant reduction in the aortic wall thickness/diameter ratio (P <0.05 vs. control) and slightly reduced relative heart weight were observed in the PB group. These effects were blunted by simultaneous stress exposure. Immunochemistry was used to stain for Bax and Bcl-2 (apoptosis markers). There was a four-fold increase in Bax/Bcl-2 ratio in the heart of PB and PB+Stress treated mice while an attenuation was observed in aortic endothelium. Results suggest that a relatively short-term continuous PB exposure may have adverse effects on the heart and blood vessels, independently of changes in MAP and HR.