In this retrospective study we analysed changes of the ST segment in patients with arterial hypertension using multi-lead body surface mapping of the electric heart field as the ST segment often shows non-specific changes and is influenced by many different conditions. We constructed isointegral maps (IIM) of chosen intervals (the first 35 ms, the first 80 ms, and the whole ST segment) in 42 patients with arterial hypertension (with and without left ventricular hypertrophy) and in the control group involving 23 healthy persons. We analysed the position and values of map extrema. Spatial distribution of voltage integrals was similar in the control group and in the “pure” hypertensives. Patients with the left ventricular hypertrophy exhibited shifts of the integral minima. Despite our expectations, the highest extrema values were found in the control group and not in the left ventricular hypertrophy group. The extrema values were similar in all hypertensives, with or without left ventricular hypertrophy. Differences could be explained neither by the influence of the age, nor by the body habitus., K. Kozlíková, J. Martinka, J. Bulas., and Obsahuje seznam literaury
The study analyses, how the political change after 1918 influenced the conditions of churches in relation to ethnic affiliations. It shows with an emphasis on the Germans in Czechoslovakia how activities of foreign confessional groups altered the terms in the examined churches. The paper concerns an overview that should follow further detailed analyses of the relation between confessional and ethnic minorities in the interwar period. and Článek zahrnuje poznámkový aparát pod čarou
Stabilisation of banks is a very important, but often disregarded stage of setting a newly built water structure in operation. The descibed type of stabilisation creates in-time appropriate bank reinforcement (here, regardless the dam) that may prevent creation and development of subsequent abrasive or erosive damage. Here are presented first experiences with the stabilisation use of so called ''earth armour'' in an interaction with a root system of suitable woody plants on an operational experimental surface. This surface is the endangered, at present already very abraded shore of the Bílovec irrigation reservoir in South Moravia. and Stabilizace břehů je velmi důležitou, mnohdy však podceňovanou součástí uvedení nově budovaného vodního díla do provozu. Právě včasná stabilizace, tedy realizace vhodného opevnění břehů (nemluvíme zde o hrázi) může zabránit vzniku a rozvoji následného abrazního, či erozního poškození. Příspěvek prezentuje první zkušenosti se stabilizačním využitím tzv. ''zemní armatury'' za spolupůsobení kořenového systému vhodných dřevin na provozované experimentální ploše. Touto plochou je ohrožené a dnes již silně abradované pobřeží závlahové nádrže Bílovec na jižní Moravě.
Mine roadways developed in highly stressed strata are subject to roof shear, which under severe conditions may manifest as the well known symptom of guttering, particularly at the roadway edge leading into the major horizontal stress. This roof shear can progressively reduce the effectiveness of bolt confinement of the strata within the lower roof horizon affecting stability of the immediate roof. This paper presents the results of a study to investigate the effectiveness of polymers as skin reinforcement in highly stressed coal mine roadways, as they may provide better roadway skin support than the currently used steel mesh. A large concrete block intercepted with artificial joints and reinforced with steel bolts without skin support, was loaded until significant slip occurred along the joints. Upon loading, a roof cavity resembling a gutter developed, as some of the jointed concrete parted from the free surface. In addition to bolts, subsequent models with identical fracture planes were supported with steel mesh or with glass reinforced polymer skin bonded to the free side. Loads and displacements were compared for models with and without skin reinforcement. As expected the skin support helped resist gutter formation, to various degrees, while increasing the residual strength of the concrete block. It was found that there was significantly less bedding displacements in models with the polymer skin, when compared with both steel mesh and no skin reinforcement. This suggests that there would be benefits to using a spray on polymeric skin as surface support in roofs subject to severe roof shear., Jan Nemcik, Ernest Baafi and Ian Porter., and Obsahuje bibliografii
Background. Previous research on the stability of personal values in the context of life transitions has usually focused on the presence of a single transition. However, life transitions in everyday life occur simultaneously with other life transitions. The aim of this longitudinal study was therefore to identify different trajectories of life transitions in young adults and to compare the stability of their personal values. Method. In the first wave of research, participants were 18-33 years old; in the second wave, they were 29-43 years old (N = 632; 392 women). In both waves, they completed Schwartzʼs Portrait Value Questionnaires (PVQ); in the second wave, they completed the Life History Calendar focusing on the presence of entry into life transitions. Results. Latent class analysis revealed two trajectories: Experienced transitions (people who experienced all observed transitions) and Partially experienced transitions (people who experienced only entry into regular employment and part of them entered cohabitation). Differential stability of personal values occurred in both trajectories. The differences in the stability of values found between the individual trajectories were insignificant, except for personal values universalism and tradition. Although before entry into life transitions, personal values were not significant predictors of belonging to a particular trajectory, after their experiencing people with the Experienced transitions trajectory more often reached lower levels of values associated with openness to change. and Dosavadní výzkum zabývající se stabilitou osobních hodnot v kontextu prožitých životních tranzic se obvykle soustředil na přítomnost jedi-né tranzice. Životní tranzice se však v běžném životě vyskytují zároveň s dalšími životními tranzicemi. Cílem této longitudinální studie byla proto identifikace různých trajektorií životních tranzic u mladých dospělých a srovnání stability jejich osobních hodnot. V první vlně výzkumu měli participanti 18–33 let; v druhé vlně měli 29–43 let (N = 632; 392 žen). V obou vlnách vyplnili Schwartzovy Dotazníky hodnotových portrétů (PVQ); v druhé vlně vyplnili Kalendář historie života zjišťující přítomnost životních tranzic. Analýza latentních tříd odhalila dvě trajektorie: Prožité tranzice (lidé, kteří prožili všechny sledované tranzice) a Částečně prožité tranzice (lidé, kteří prožili vstup do pravidelné-ho zaměstnání a část z nich kohabitaci). Dife-renciální stabilita osobních hodnot se objevila u obou trajektorií. Zjištěné rozdíly v stabilitě hodnot mezi jednotlivými trajektoriemi byly nevýznamné, vyjma osobních hodnot univerza-lismus a tradice. Ačkoli před prožitím životních tranzic nebyly osobní hodnoty významnými prediktory příslušnosti ke konkrétní trajektorii, po jejich prožití lidé s trajektorií Prožité tranzice dosahovali častěji nižší úrovně v hodnotách spo-jených s otevřeností změně.
In this paper, a five-dimensional energy demand-supply system has been considered. On the one hand, we analyze the stability for all of the equilibrium points of the system. For each of equilibrium point, by analyzing the characteristic equation, we show the conditions for the stability or instability using Routh-Hurwitz criterion. Then numerical simulations have been given to illustrate all of cases for the theoretical results. On the other hand, by introducing the phenomenon of time delay, we establish the five-dimensional energy demand-supply model with time delay. Then we analyze the stability of the equilibrium points for the delayed system by the stability switching theory. Especially, Hopf bifurcation has been considered by showing the explicit formulae using the central manifold theorem and Poincare normalization method. For each cases of the theorems including the Hopf bifurcation, numerical simulations have been given to illustrate the effectiveness of the main results.
A singularly perturbed linear time-invariant time delay controlled system is considered. The singular perturbations are subject to the presence of two small positive multipliers for some of the derivatives in the system. These multipliers (the parameters of singular perturbations) are of different orders of the smallness. The delay in the slow state variable is non-small (of order of 1). The delays in the fast state variables are proportional to the corresponding parameters of singular perturbations. Three much simpler parameters-free subsystems are associated with the original system. It is established that the exponential stability of the unforced versions of these subsystems yields the exponential stability of the unforced version of the original system uniformly in the parameters of singular perturbations. It also is shown that the stabilization of the parameters-free subsystems by memory-free state-feedback controls yields the stabilization of the original system by a memory-free state-feedback control uniformly in the parameters of singular perturbations. Illustrative examples are presented.
A frequently used technological solution of reducing the time varying forces transmitted between the rotor and its casing is represented by application of a flexible suspension with damping devices added to the constraint elements. To achieve their optimum performance their damping effect must be controllable. For this purpose a concept of a hybrid damping device working on the principle of squeezing the layers of normal and magnetorheological oils have been developed. Here in this article, there is investigated influence of the proposed damping element on stabilty of the rotor vibrations induced by its imbalance during the steady state operating regimes. The stability is assessed by the evolutive method which is based on evaluation of eigenvalues of the system linearized in a small neighbourhood of the rotor phase trajectory and calculation of the corresponding damping ratio or logarithmic decrement. and Obsahuje seznam literatury
Aging induced loss of chlorophyll (Chl), carotenoids (Car) and proteins was studied in suspensions of isolated wheat chloroplasts incubated in the light or dark. Faster rate of pigment loss in the light was due to photodestruction of pigments. Compared to Chl, a greater loss of Car in the light was due to photoprotective action of Car towards Chl resulting in its own destruction. The total protein content was lowered more in the light than in dark. Soluble proteins of chloroplasts declined by 36 %, whereas membrane proteins showed a loss of only 8 % after 6 d of light incubation.
In our study we find, from the analysis of VLBI observations, small quasi-periodic fluctuations of the period and quality factor of retrograde Free Core Nutation (FCN), ranging mainly between 429.8 to 430.8 days and 17000 to 21000, respectively. To this end, we use resonant effects in several dominant forced nutation terms to calculate the period and quality factor of FCN in running 6-year intervals. We also recently demonstrated that the atmospheric and oceanic excitations are capable of exciting FCN. Both amplitude and phase of the geophysically excited motion are consistent with the values observed by VLBI, in the interval of tens of years. The geophysical excitations are now numerically integrated, using Brzeziński’s broadband Liouville equations, and removed from the observed celestial pole offsets. The remaining part is then used to derive the period and quality factor of FCN in running intervals, and to study the temporal stability of these important Earth parameters. It is demonstrated that the observed quasi-periodic variations of both parameters are probably not caused by these geophysical excitations., Jan Vondrák and Cyril Ron., and Obsahuje bibliografii