The aim of this study was to assess the impact of different vegetation on the distribution of rainfall (due to throughfall and stemflow), water regime, and Al and SO4 2- leaching from forest soils. The water flow and Al and SO4 2- transport were modeled using HYDRUS-1D. The study was performed at two elevation transects on the Paličník and Smědava Mountain in Jizera mountains. Podzols and Cambisols were prevailing soil units in this area. It was shown that the effect of the precipitation redistribution on water regime was considerable in the beech forest, while it was almost negligible in the spruce forest. Redistribution of precipitation under trees caused runoff (in one case), increased water discharge through the soil profile bottom, reduction of water storage in the soil, and thus reduction of root water uptake. Simulated Al leaching from the soil profile was determined mainly by the initial Al content in the soil profile bottom. Leaching of SO4 2- was mainly determined by its initial content in the soil and to a lesser extent by redistributed precipitation and SO4 2- deposition.
This study is focused on the snowmelt runoff simulations for the upper Hron basin using dte degree-day approach of the SRM model. Our effort was directed at the determination and selection of input data and model parameters using GIS tools. The aim of this paper was to simulate the snowmelt runoff using only regularly measured data, without their special pre-processing. Comparison between measured and computed runoff indicates that the SRM model could be used for the snowmelt runoff simulation for the upper Hron basin. Results for the smaller upper Telgart subbasin were not so acceptable, because of lack of representative input data, which is essential for the determination of the snow depletion curve. and Práca je venovaná simulácii odtoku zo snehu pre povodie horného Hrona s využitím modelu odtoku zo snehu - SRM. Hlavným cieľom práce bolo posúdiť a otestovať možnosti výberu a určenia vstupných údajov a kalibrácie parametrov do modelu SRM s využitím dát pravidelne meraných v sieti meteorologických staníc. Z výsledkov vyplýva, že SRM veľmi dobre simuluje prietok pre povodie horného Hrona ako celku. Simulácia pre povodie horného Hrona rozdeleného na dve výškové zóny, a najmä pre čiastkové povodie Hrona po Telgárt, nedosiahla akceptovateľné výsledky. Tento fakt spôsobili najmä nedostatečné vstupné údaje. Kritickým sa ukázali najmä vstupné informácie o priestorovom rozložení snehovej pokrývky.
Grid code modifications require the in service fixed speed wind turbines to ride-through grid faults. Voltage dips due to electrical grid faults generate transients of the generator electromagnetic torque. These transients result in significant stresses and vibrations affecting the fatigue life of the components. An electro-mechanical model was built to simulate the grid faults that excite the asynchronous generator with poorly damped stator flux oscillations. These oscillations cause transients of the generator electromagnetic torque. This article focuses in estimating the resulting significant stresses transients affecting the fatigue life of drivetrain system due to voltage dips. A rainflow cycle counting method was developed to evaluate the fatigue life of the mechanical system. The methodology analyses the stress history and estimates the mean and amplitudes of the counted cycles, and time of duration to calculate the accumulated damage occurred during the voltage dip event. and Obsahuje seznam literatury
The raster based on Fresnel’s optics working as converging cylindrical optic are widely used in the range of utilization of the Sun energy as construction elements of translucent roofs and facades. The energetic balance of building’s interior equipped of these elements can be simulated mathematically and proved by experiment imitating precisely real conditions of an application. The described simulator was developed for such experiments. The angle between incoming radiation and the normal of a glass surface can be set by this simulator. This results present the functionality of the described device. and Rastry na bázi Fresnelovy optiky činné jako spojná válcová optika nebo hranoly nacházejí významné uplatnění v oblasti využití sluneční energie jako konstrukční prvky průsvitných střech a fasád. Energetickou bilanci interiérů budov vybavených zmíněnými prvky lze simulovat výpočtem a ověřit experimentem organizovaným tak, aby se co nejpřesněji napodobily skutečné podmínky aktuální aplikace. K příslušným experimentům byl vyvinut uvedený simulátor, kterým lze nastavit úhel mezi přicházejícím zářením a normálou k prosklené ploše. Uvedené výsledky prokazují funkceschopnost navrženého zařízení.
Ghrelin is a gut peptide produced mainly by stomach, well known to induce appetite stimulatory actions. Obestatin, a recently identified peptide derived from preproghrelin, was initially described to antagonize stimulatory effect of ghrelin on food intake. The postprandial response of obestatin and its relationship with ghrelin in humans remains unknown. We therefore investigated the postprandial response of obestatin and total ghrelin, acyl and desacyl ghrelin and neuropeptide Y (NPY) to a high-carbohydrate breakfast (1 604 kJ) in eight healthy women (age: 24.2±0.82 years; BMI 21.6±0.61 kg/m2). Blood samples were collected before the meal, and 30, 60, 90, 120 and 150 min after the breakfast consumption. Postprandial plasma obestatin concentrations significantly decreased compared with preprandial levels as well as total ghrelin concentrations and reached the lowest values 90 and 120 min after the meal consumption, respectively (p 0.05). Plasma acyl and desacyl ghrelin concentrations decreased after the breakfast and reached lowest values in 30 and 60 min, respectively (p<0.05). Plasma NPY concentrations were lower than preprandial levels 90 and 150 min after consuming breakfast (p<0.05). In conclusion, we demonstrated in healthy young women that plasma obestatin concentrations decrease similarly to ghrelin after a high-carbohydrate breakfast., D. Sedláčková, I. Dostálová, V. Hainer, L. Beranová, H. Kvasničková, M. Hill, M. Haluzík, J. Nedvídková., and Obsahuje bibliografii a bibliografické odkazy
The chlorophyll fluorescence Fo, excited by polsed ultra-weak blue radiatíon, and thermoluminescence (TL) were recorded in ďie same sample. Temperature-dependent variations of the fluorescence yield influenced ťhe TL emission.
The article deals with simultaneous use of relief and polarization microscopy. This process (described in detail here) provides a view of a birefringent structure even in dimly viewed architecture of living cells. Using simple devices and two methods described here one gets a very contrasting relief picture with a 3D effect. The method is illustrated by two examples of biological objects (coccal and trichal green algae) studied by two methods (polarizing microscopes LOMO St. Petersburg - retractable diaphragm of dark neutral density filter and Carl Zeiss Jena Polmi A - eccentrically retractable aperture diaphragm). Both these methods can provide good results when observing birefringent structures and with microphotographs. The methods can be recommended for viewing objects whose light refractive index approaches the refractive index of the surrounding environment (e.g. granules in cell cytoplasm) and determining the maximum birefringence of these structure using crossed polarizers (nicols), first-order quartz compensator and rotary table. and Článek se zabývá simultánním použitím reliéfní a polarizační mikroskopie. Tento postup (zevrubně popsaný v práci) umožňuje zjistit dvojlomné struktury i v nezřetelně zobrazené architektuře živé buňky. Pomocí jednoduchých prostředků (popsány dva způsoby práce) dostaneme velmi kontrastní reliéfní obraz s 3D-efektem. Metoda je ukázána na dvou příkladech biologických objektů (kokální a trichální zelené řasy) studovaných dvěma způsoby (polarizační mikroskopy LOMO St. Petersburg - zasunovací clona z tmavého neutrálního filtru a Carl Zeiss Jena Polmi A - excentricky vysunovatelná aperturní clona). Oběma těmito způsoby lze dosáhnout dobrých výsledků (pozorování dvojlomných struktur) i mikrofotografií. Metody lze doporučit pro pozorování objektů, jejichž index lomu světla se blíží indexu lomu okolního prostředí (např. granula v cytoplasmě buněk) a pomocí zkřížených polarizátorů (nikolů), křemenného kompenzátoru I. řádu a otočného stolku zjistit i maximální dvojlom těchto struktur.
a1_Statins, the inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are most frequently used drugs in the prevention of coronary artery disease due to their cholesterol- lowering activity. However, it is not exactly known whether these effects of statins or those independent of cholesterol decrease account for the protection ag ainst myocardial ischemia- reperfusion (I/R) injury. In this study, we investigated the effect of 5-day treatment with simvastatin (10 mg/kg) in Langendorff- perfused hearts of healthy control (C) and diabetic- hypercholesterolemic (D-H; strept ozotocin + high fat-cholesterol diet, 5 days) rats subjected to 30-min global ischemia followed by 40-min reperfusion for the examination of postischemic contractile dysfunction and reperfusion-induced ventricular arrhythmias or to 30-min (left anterior descending) coronary artery occlusion and 2-h reperfusion for the infarct size determination (IS; tetrazolium stai ning). Postischemic recovery of left ventricular developed pressu re (LVDP) in animals with D-H was improved by simvastatin therapy (62.7±18.2 % of preischemic values vs. 30.3±5.7 % in the untreated D-H; P<0.05), similar to the values in the simvastatin-treated C group, which were 2.5-fold higher than those in the untreated C group. No ventricular fibrillation occurred in the simvastatin-treated C and D-H animals during reperf usion. Likewise, simvastatin shortened the duration of ventri cular tachycardia (10.2±8.1 s and 57.8±29.3 s in C and D-H vs. 143.6±28.6 s and 159.3±44.3 s in untreated C and D-H, respectively, both P<0.05). The decreased arrhythmogenesis in the simvastatin-treated groups correlated with the limitation of IS (in % of risk area) by 66 % and 62 % in C and D-H groups, respectively. However, simvastatin treatment decreased plasma cholesterol levels neither in the D-H animals nor in C., a2_The results indicate that other effects of statins (independent of cholesterol lowering) are involved in the improvement of contractile recovery and attenuation of lethal I/R injury in both, healthy and diseased individuals., A. Adameová, A. Harčárová, J. Matejíková, D. Pancza, M. Kuželová, S. Čarnická, P. Švec, M. Barteková, J. Styk, T. Ravingerová., and Obsahuje bibliografii
Pulmonary hypertension is a group of disorders characterized by elevated mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance. To test our hypothesis that combining two drugs useful in experimental pulmonary hypertension, statins and dehydroepiandrosterone sulfate (DHEA-S), is more effective than either agent alone, we induced pulmonary hypertension in adult male rats by exposing them to hypoxia (10 %O2) for 3 weeks. We treated them with simvastatin (60 mg/l) and DHEA-S (100 mg/l) in drinking water, either alone or in combination. Both simvastatin and DHEA-S reduced mPAP (froma mean±s.d. of 34.4±4.4 to 27.6±5.9 and 26.7±4.8 mmHg, respectively), yet their combination was not more effective (26.7±7.9 mmHg). Differences in the degree of oxidative stress (indicated by malondialdehydeplasma concentration), the rate of superoxide production (electron paramagnetic resonance), or blood nitric oxide levels (chemiluminescence) did not explain the lack of additivity of the effect of DHEA-S and simvastatin on pulmonary hypertension. We propose that the main mechanism of both drugs on pulmonary hypertension could be their inhibitory effect on 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, which could explain their lack of additivity.