Urychlovače slouží k získávání intenzivních svazků iontů nebo částic s vysokou rychlostí a energií. Kinetické energie dodávané současnými urychlovači jsou v rozsahu od několika stovek keV do několika TeV (1 eV = 1.6 x 10(19) J). V makrosvětě tyto energie nikoho neohromí, ale v mikrosvětě je vše jinak: rychlost protonu s kinetickou energií 200 keV činí 2 % rychlosti světla, u elektronu se stejnou kinetickou eneregií je to dokonce 70 %. Ve světě vysokých energií se slovo urychlovač stává trochu nesmyslným, neboť rychlost částic už skoro neroste (blíží se rychlosti světla), ale roste jejich energie a tudíž i relativistická hmotnost., Zdeněk Doležal., and Obsahuje bibliografii
In this paper the concept of a fuzzy contraction∗ mapping on a fuzzy metric space is introduced and it is proved that every fuzzy contraction∗ mapping on a complete fuzzy metric space has a unique fixed point.
Computed tomography (CT) is an effective diagnostic modality for three-dimensional imaging of bone structures, including the geometry of their defects. The aim of the study was to create and optimize 3D geometrical and real plastic models of the distal femoral component of the knee with joint surface defects. Input data included CT images of stifle joints in twenty miniature pigs with iatrogenic osteochondrosis-like lesions in medial femoral condyle of the left knee. The animals were examined eight and sixteen weeks after surgery. Philips MX 8000 MX and View workstation were used for scanning parallel plane cross section slices and Cartesian discrete volume creation. On the average, 100 slices were performed in each stifle joint. Slice matrices size was 512 x 512 with slice thickness of 1 mm. Pixel (voxel) size in the slice plane was 0.5 mm (with average accuracy of ± 0.5 mm and typical volume size 512 × 512 × 100 voxels). Three-dimensional processing of CT data and 3D geometrical modelling, using interactive computer graphic system MediTools formerly developed here, consisted of tissue segmentation (raster based method combination and 5 % of manual correction), vectorization by the marching-cubes method, smoothing and decimation. Stifle- joint CT images of three individuals of different body size (small, medium and large) were selected to make the real plastic models of their distal femurs from plaster composite using rapid prototyping technology of Zcorporation. Accuracy of the modeling was ± 0.5 mm. The real plastic models of distal femurs can be used as a template for developing custom made press and fit scaffold implants seeded with mesenchymal stem cells that might be subsequently implanted into iatrogenic joint surface defects for articular cartilage-repair enhancement., P. Krupa, P. Kršek, M. Javorník, O. Dostál, R. Srnec, D. Usvald, P. Proks, H. Kecová, E. Amler, J. Jančář, P. Gál, L. Plánka, A. Nečas., and Obsahuje bibliografii
In the pulmonary circulation, resistive and compliant properties
overlap in the same vessels. Resistance varies nonlinearly with
pressure and flow; this relationship is driven by the elastic
properties of the vessels. Linehan et al. (1982) correlated the
mean pulmonary arterial pressure and mean flow with resistance
using an original equation incorporating the distensibility of the
pulmonary arteries. The goal of this study was to validate this
equation in an in vivo porcine model. In vivo measurements were
acquired in 6 pigs. The distensibility coefficient (DC) was
measured by placing piezo-electric crystals around the pulmonary
artery (PA). In addition to experiments under pulsatile conditions,
a right ventricular (RV) bypass system was used to induce
a continuous pulmonary flow state. The Linehan's equation was
then used to predict the pressure from the flow under continuous
flow conditions. The diameter-derived DC was 2.4 %/mmHg
(±0.4 %), whereas the surface area-based DC was 4.1 %/mmHg
(±0.1 %). An increase in continuous flow was associated with
a constant decrease in resistance, which correlated with the
diameter-based DC (r=-0.8407, p=0.044) and the surface areabased DC (r=-0.8986, p=0.028). In contrast to the Linehan’s
equation, our results showed constant or even decreasing
pressure as flow increased. Using a model of continuous
pulmonary flow induced by an RV assist system, pulmonary
pressure could not be predicted based on the flow using the
Linehan’s equation. Measurements of distensibility based on the
diameter of the PA were inversely correlated with the resistance.
In three separate experiments, the effectiveness of a SPAD-502 portable chlorophyll (Chl) meter was evaluated for estimating Chl content in leaves of Eugenia uniflora seedlings in different light environments and subjected to soil flooding. In the first experiment, plants were grown in partial or full sunlight. In the second experiment plants were grown in full sunlight for six months and then transferred to partial sunlight or kept in full sunlight. In the third experiment plants were grown in a shade house (40% of full sunlight) for six months and then transferred to partial shade (25-30% of full sunlight) or full sunlight. In each experiment, plants in each light environment were either flooded or not flooded. Non-linear regression models were used to relate SPAD values to leaf Chl content using a combination of the data obtained from all three experiments. There were no significant effects of flooding treatments or interactions between light and flooding treatments on any variable analyzed. Light environment significantly affected SPAD values, chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll [Chl (a+b)] contents in Experiment I (p≤0.01) and Experiment III (p≤0.05). The relationships between SPAD values and Chl contents were very similar among the three experiments and did not appear to be influenced by light or flooding treatments. There were high positive exponential relationships between SPAD values and Chl (a+b), Chl a, and Chl b contents. and M. S. Mielke, B. Schaffer, C. Li.
A comparison of the effects of ultrasound produced by low- and high-frequency ultrasonic apparatuses upon biological systems is one of the basic problems when studying ultrasound cavitation effects. One possibility for how to compare these effects is the indirect method which uses well-known physical quantities characterizing the interaction of ionizing radiation with matter and which also converts these quantities to one common physical quantity. The comparison was performed with two methods applied to the chemical dosimetry of ionizing radiation. The first method employed a twocomponent dosimeter which is composed of 50 % chloroform and 50 % re-distilled water (i.e. Taplin dosimeter). The other method used a modified iodide dosimeter prepared from a 0.5 M potassium iodide solution. After irradiation or ultrasound exposure, measurable chemical changes occurred in both dosimeters. The longer the exposure, the greater the chemical changes. These effects are described by the relationship of these changes versus the exposure times in both dosimeters. The UZD 21 ultrasonic disintegrator (with a frequency of 20 kHz, 50 % power output) was used as a lowfrequency ultrasound source, and the BTL-07 therapeutic instrument (with a frequency of 1 MHz and intensity of 2 W/cm2) was used as a high-frequency cavitation ultrasound source. For comparison, a 60Co gamma source was applied (60Co, gamma energies of 1.17 and 1.33 MeV, activity of 14 PBq). Results of this study have demonstrated that the sonochemical products are generated during exposure in the exposed samples of both dosimeters for all apparatuses used. The amount of these products depends linearly upon the exposure time. The resulting cavitation effects were recalculated to a gray-equivalent dose (the proposed unit is cavitation gray [cavitGy]) based on the sonochemical effects compared to the effects of ionizing radiation from the 60Co source., B. Kratochvíl, V. Mornstein., and Obsahuje bibliografii
Electrogastrography (EGG) is a non-invasive method for the assessment of gastric myoelectrical activity. Porcine EGG is comparable with human one. The purpose of this study was to evaluate the effect of atropine and neostigmine on the EGG in experimental pigs. Adult female pigs were administrated atropine (1.5 mg i.m., n=6) and neostigmine (0.5 mg i.m., n=6) after the baseline EGG, followed by a 90-min trial recording (MMS, Enschede, the Netherlands). Running spectral analysis was used for the evaluation. The results were expressed as dominant frequency of slow waves and EGG power (areas of amplitudes). Neostigmine increased continuously the dominant frequency and decreased significantly the EGG power. Atropine did not change the dominant frequency significantly. However, atropine increased significantly the EGG power (areas of amplitudes) from basal values to the maximum at the 10-20-min interval. After that period, the areas of amplitudes decreased significantly to the lowest values at the 60-90-min interval. In conclusion, cholinergic and anticholinergic agents affect differently EGG in experimental pigs., J. Květina, I. Tachecí, M. Pavlík, M. Kopáčová, S. Rejchrt, T. Douda, M. Kuneš, J. Bureš., and Obsahuje bibliografii
Presented study is aimed at using additional information to improve process represen-tativity of hydrological modelling. The study region is the Haute-Mentue catchment lo-cated in the western part of Switzerland, 20 km north of Lausanne. Previous research in this catchment allowed improving of the understanding of the runoff generation by combining point soil moisture measurements (TDR) and integrating measurements both at the hillslope scale (dye tracing) and at the catchment scale (environmental tracing). In this work, environmental tracing information will be integrated into a semi-distributed hydrological model, which is a modified version of TOPMODEL taking into account a rapid stormflow generation above a less permeable soil horizon. Additional information has been incorporated by using a version of simulated annealing adapted for multi-criteria optimisation. and Štúdia je venovaná využitiu dodatkových informácií pri reálnejšej simulácii hydrologických procesov v zrážkovo-odtokovom modeli. Študovanou oblasťou je povodie Haute-Mentue, ležiace v západnej časti Švajčiarska, 20 km od Lausanne. Predchádzajúci výskum v tomto povodí, založený na kombinácii bodových meraní (TDR) a integrovaných meraní v mierke svahu (farbiace skúšky) a povodia (prirodzené stopovače), zlepšil vedomosti o tvorbe odtoku. V tejto štúdii sú informácie získané prirodzenými stopovačmi použité pri posudzovaní výsledkov simulácie odtoku pomocou semidistribuovaného hydrologického modelu (modifikovaná verzia modelu TOPMODEL, ktorá uvažuje s mechanizmom tvorby odtoku nasýtením nad vrstvou pôdy s nižšou priepustnosťou). Ďalšou dodatkovou informáciou boli výsledky automatickej optimalizácie parametrov modelu pmocou metódy vychádzajúcej z analógie medzi optimalizáciou parametrov modelu a rozdelením častíc v tuhnúcej kvapaline (tzv. simulated annealing), adaptovanej na optimalizáciu podľa viacerých kritérií.
Modern methods of monitoring landslides are based on observations of both: direct surveying (GNSS, electronic tachymetry, geometric levelling) and remote sensing (terrestrial and aerial photogrammetry, laser scanning, interferometry), as well as surface and subsurface geotechnical observations (e.g. inclinometers, extensometers, piezometers, etc.). Due to the high cost of installation of these devices and its measurement, the implementations of these methods are usually used on well-define d objects, with established landslide activity and high risk to people’s lives. The main objective of the project was to design, create and do practical tests of simple and inexpensive measurement devices, which detect first symptoms of a potential landslide movements and alert of an existing threat. These devices would be some kind of an early warning system that would register the occurrence of the first movements of the surface layers of soil, which would be a signal to start of geodetic and geotechnical monitoring of potential landslides., Bartłomiej Ćmielewski, Bernard Kontny and Kazimierz Ćmielewski., and Obsahuje bibliografické odkazy
Three cultivars of winter hexaploid triticales M2A/JAIN, DF 99/Yogu "S5", and Asseret were grown on nutrient solution with or without 75 mM NaCl. Stomatal permeability and transpiration rate decreased in all salt-stressed triticale cultivars. Net photosynthetic rate (PN) of cv. M2A and Asseret was not affected by NaCl. On the contrary, PN in cv. DF99 was reduced in relation to control plants. A higher water-use efficiency under saline conditions led to better salt tolerance of cv. M2A compared to cvs. Asseret and DF99. and A. Morant-Avice ... [et al.].