Showing papers by "Charles University in Prague published in 1987"
TL;DR: The maximal rate of bone loss, as judged by radiogrammetry of the metacarpals and by dual-photon absorptiometry of the lumbar spine, coincided with the peak of the dissociation between urinary hydroxyproline excretion and/or plasma tartrate resistant acid phosphatase activity, indicating continuous imbalance of bone remodeling in the patients.
272 citations
TL;DR: The minimax approach to stochastic programming with recourse deals with the case of incomplete knowledge of the distribution F of the random coefficients and leads to the deterministic program [ILM0001] where x is a given set of admissible solutions, φ is a recourse function and f is aGiven set of distributions.
Abstract: The minimax approach to stochastic programming with recourse deals with the case of incomplete knowledge of the distribution F of the random coefficients. It leads to the deterministic program [ILM0001] where x is a given set of admissible solutions, φis a recourse function and f is a given set of distributions. To express the objective function of (*) in a form suitable for further computation, general results on the moment problem can be used.In section 1, the main ideas are briefly surveyed. Subsequently, the method is applied to (*) in section 2. It is shown how the results can be used both to draw conclusions on robustness of the optimal value of the given stochastic program with respect to the set of distributions considered, and to study sensitivity of the optimal solution with respect to a specified distribution. In section 3, an application to a stochastic model of a water resource system with incomplete knowledge about the distribution of the random demand is suggested
177 citations
TL;DR: The effects of Cu2+, Zn2+, Cd2+ and Pb2+ on growth and the biochemical characteristics of photosynthesis were more expressed in barley than in maize seedlings and the chlorophyll content was decreased in barley shoots and increased in maize.
Abstract: The effects of Cu2+, Zn2+, Cd2+ and Pb2+ on growth and the biochemical characteristics of photosynthesis were more expressed in barley (Hordeum vulgare L.) than in maize (Zea mays L.) seedlings. The barley and maize seedlings exhibited retardation in shoot and root growth after exposure of Cu2+, Cd2+ and Pb2+. The Zn2+ions practically did not influence these characteristics. The total protein content of barley and maize roots declined with an increase in heavy metal ion concentrations. The protein content of barley shoots was only slighly decreased with an increase in heavy metal ion concentrations, but the protein content in maize shoots was increased under the same conditions. The chlorophyll content was decreased in barley shoots and increased in maize. The ribulose-l,5-bisphosphate carboxylase (RuBPC, EC 4.1.1.39) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activities were decreased drastically by Cu2+, Cd2+ and Pb2+ in thein vivo experiments. The tested heavy metal ions affect photosynthesis probably mainly by inhibition of these key carboxylating enzymes: this mechanism was studied in thein vitro experiments.
113 citations
TL;DR: In this article, the authors studied the finite element approximation to nonlinear second order elliptic boundary value problems with mixed Dirichlet-Neumann boundary conditions and proved that the convergence rate of the method is O(h) without the use of Green's theorem.
Abstract: The study of the finite element approximation to nonlinear second order elliptic boundary value problems with mixed Dirichlet-Neumann boundary conditions is presented. In the discretization variational crimes are commited (approximation of the given domain by a polygonal one, numerical integration). With the assumption that the corresponding operator is strongly monotone and Lipschitz-continuous and that the exact solutionu∈H1(Ω), the convergence of the method is proved; under the additional assumptionu∈H2(Ω), the rate of convergenceO(h) is derived without the use of Green's theorem.
102 citations
Journal Article•
65 citations
TL;DR: The ventilatory threshold (VT) was determined on a treadmill in highly trained male marathon, male and female long-distance, young male long- distance, adultmale and female and young female middle-distance runners, modern pentathlonists, adult canoeists of both sexes, youngmale canoeists and football players, and on a bicycle ergometer in table tennis players, water slalom paddlers, young female canoeists rowers, and ice hockey players.
Abstract: The ventilatory threshold (VT) was determined on a treadmill in highly trained male marathon, male and female long-distance, young male long-distance, adult male and female and young female middle-distance runners, modern pentathlonists, adult canoeists of both sexes, young male canoeists and football players, and on a bicycle ergometer in table tennis players, water slalom paddlers, young female canoeists rowers, and ice hockey players. Young female canoeists were also examined on the paddling ergometer and rowers on the rowing ergometer. VT expressed in %VO2 max was higher the longer the duration of racing performance (in marathoners 86.7%). %VO2 max at the VT level depends on the type of load and is higher the better the organism is adapted to a load. In young female canoeists and rowers examined on the bicycle ergometer, we found the VT level at 74.2% and 74.6% of %VO2 max, respectively. In the case of specific loading, we recorded 84.8% and 85.0% of %VO2 max, respectively, in the same athletes. In the case of nonspecific loading highly trained individuals may have low VT values close to the level characteristic for normal subjects. In relatively equally trained young and adult athletes we did not find significant differences in %VO2 max at the VT level (for long-distance runners, 85.2% and 85.3%, respectively, in female middle-distance runners, 82.8% and 82.7%, respectively, and in canoeists 81.3% and 78.9% of %VO2 max, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
65 citations
TL;DR: The clinical utility of serum osteocalcin as a marker of bone formation is similar but not identical to that of bone alkaline phosphatase, according to a prospective study of 12 women.
Abstract: Serum osteocalcin levels peaked 1 yr after oophorectomy in a prospective study of 12 women. Estrogen treatment restored serum osteocalcin to the normal range within 4 months of therapy. The changes in serum osteocalcin preceded those in bone alkaline phosphatase activity by 1–2 months, in these oophorectomized patients and during estrogen treatment. The changes in these two markers of bone formation over time were significantly different from those in urinary hydroxyproline excretion. A significant positive correlation was found between bone alkaline phosphatase and serum osteocalcin levels in patients after oophorectomy and in 18 patients with primary hyperparathyroidism. Significant positive correlations also were found between the biochemical indices of osteoblastic function and urinary hydroxyproline excretion and/or nephrogenous cAMP in primary hyperparthyroidism. In most of the patients with primary hyperparathyroidism, however, the elevation in bone alkaline phosphatase was more marked than that in...
62 citations
TL;DR: In this paper, a one-step version of the M-estimator M n starting with an initial estimator T n is proposed which inherits the efficiency properties of M n and the breakdown-point of T n respectively.
Abstract: In the linear regression model, a one-step version of the M-estimator M n starting with an initial estimator T n is proposed which inherits the efficiency properties of M n and the breakdown-point of T n respectively; this even in the case that the rate of consistency of T n is lower than Such results suggest a potentially valuable method for combining high efficiency with high breakdown point. They follow from a general asymptotic linearity result which holds for M -estimators with kernels which are not everywhere differentiable.
54 citations
TL;DR: The formation of multinucleate giant cells was studied after the subcutaneous implantation of cellophane foil into 25 Wistar rats and the positivity of widely extended MGCs for acid phosphatase and sodium tetrazolium reductase seems to be lower than that in Langhans' or Touton's cells.
53 citations
TL;DR: Several new classes of graphs on which the maximum-weight clique problem is solvable in polynomial time are introduced, and the central idea is that every clique of any of the authors' graphs is contained in some member of aPolynomial-sized collection of induced subgraphs that are complements of bipartite graphs.
Abstract: We introduce several new classes of graphs on which the maximum-weight clique problem is solvable in polynomial time. Their common feature, and the central idea of our algorithms, is that every clique of any of our graphs is contained in some member of a polynomial-sized collection of induced subgraphs that are complements of bipartite graphs.
50 citations
TL;DR: In this article, a survey of stochastic programming decision models with incomplete knowledge of the distribution of the random parameters is presented, which can be used to study robustness of the optimal solution and the optimal value of the objective function relative to small changes of the underlying distribution.
Abstract: The possibility of successful applications of stochastic programming decision models has been limited by the assumed complete knowledge of the distribution Fof the random parameters as well as by the limited scope of the existing numerical procedures. We shall give a survey of selected methods which can be used to deal with the incomplete knowledge of the distribution F, namely to study robustness of the optimal solution and the optimal value of the objective function relative to small changes of the underlying distribution and to get error bounds in approximation schemes.
TL;DR: In this paper, the magnetic structures and some relevant bulk magnetic properties of R(Cu, Ni) 2 (R = Tb, Tb z Y 1− z, Dy, Ho, Er and Tm) are summarized.
TL;DR: Physical properties of organosilicon, halocarbon, hydrocarbon and composite (metal-doped) plasma polymer films are concisely reviewed and proposed applications of these films in optics and electronics are presented as discussed by the authors.
TL;DR: The procedure is an alternative to the AAS determination of the total mercury content in sediments, especially with heavily polluted samples (mercury concentrations up to 0.01%), and the analytical parameters of the procedures compared.
TL;DR: In the late phase of the fever occurring 120 or more min after i.v. injection of endotoxin (1 ug/kg) to female rabbits, marked shifts of thresholds for respiratory evaporative heat loss and for peripheral vasodilatation to higher body core temperatures were observed as discussed by the authors.
Abstract: In the late phase of the fever occurring 120 or more min after i.v. injection of endotoxin (1 ug/kg) to female rabbits, marked shifts of thresholds for respiratory evaporative heat loss and for peripheral vasodilatation to higher body core temperatures were observed. In contrast, the threshold body core temperature for cold thermogenesis was shifted downwards. As a result, the interthreshold zone was widened. Within the body temperature range of 37.4 to 39.9°C neither heat production or heat loss mechanisms were operant and the body temperature was determined mainly by passive heat transfer between the body and the environment. Outside this zone, the sensitivities of the heat and cold deference activities to changes in body core temperature appeared to be unchanged.
TL;DR: It is concluded that “peripheral” tetrahydrobiopterin deficiency is caused by a partial PTS deficiency with sufficient activity to cover the tetrahyllalanine requirement of tyrosine 3-hydroxylase and tryptophan 5-hydroxyylase in brain but not enough for phenylalanine 4-hydrogenase in liver.
Abstract: Four patients in three families with “peripheral” tetrahydrobiopterin deficiency were investigated. They were characterized biochemically by a tetrahydrobiopterin-responsive hyperphenylalaninaemia, a high neopterin/biopterin ratio in urine and plasma, and normal or elevated concentrations of biopterin, homovanillic acid, and 5-hydroxyindole acetic acid in cerebrospinal fluid. From measurements of the activity of erythrocyte 6-pyruvoyl tetrahydropterin synthase (PTS, formerly called phosphate-eliminating enzyme) and phenylalanine loading tests in the patients and their parets, one patient was demonstrated to be heterozygous for PTS deficiency. The others were obviously genetic compounds (allelism) with incomplete PTS deficiency. Three of the children developed normally, two of them under treatment with tetrahydrobiopterin. In the latter two patients, significantly lower concentrations of biopterin, homovanillic acid, and 5-hydroxyindole acetic acid in cerebrospinal fluid were noted at age 7 months (when treatment was interrupted) than those observed at 3 and 5 weeks, respectively. The infant who is heterozygous for PTS deficiency was born small for gestational age and showed a moderately delayed psychomotor development. It is concluded that “peripheral” tetrahydrobiopterin deficiency is caused by a partial PTS deficiency with sufficient activity to cover the tetrahydrobiopterin requirement of tyrosine 3-hydroxylase and tryptophan 5-hydroxylase in brain but not enough for phenylalanine 4-hydroxylase in liver. For therapy, tetrahydrobiopterin, 2–5 mg/kg in a single oral dose per day, is recommended to keep plasma phenylalanine normal. A careful observation of the mental development is indicated.
TL;DR: Penicillium chermesinum and some strains of Penicilli claviforme seem to be the most suitable food, but also some Alternaria species and Mucor racemosus are very palatable for mites tested.
Abstract: The start of the grazing, rate of the consumption of fungi, mite population growth and humidity conditions were observed. Differences were found in regard to the attractiveness as well as to the nutritional value expressed by the population dynamics. Penicillium chermesinum and some strains of Penicillium claviforme seem to be the most suitable food, but also some Alternaria species and Mucor racemosus are very palatable for mites tested. The population explosion of bacteria associated with mites during the consumption of some fungi followed by the population increase of mites of the family Anoetidae were recorded. The total and irreversible destruction of some fungi tested was observed as a consequence of the mite grazing.
Zusammenfassung
Untersuchungen zur Nahrungsselektion einer Freilandpopulation von Tyrophagus putrescentiae (Schrank) (Acari, Acarida)
Untersuchungskriterien waren der Beginn des Abweidens des Pilzrasens, die Verzehrungsrate, das Populationswachstum der Milbe sowie die Feuchtigkeitsbedingungen. Unterschiede konnten sowohl hinsichtlich der Attraktivitat als auch des Nahrungswerts, ausgedruckt durch das Populationswachstum, festgestellt werden. Penicillium chermesinum und einige Stamme von Penicillium claviforme scheinen als Nahrung besonders geeignet zu sein, aber auch einige Alternaria-Arten und Mucor racemosus sind fur die getesteten Milben sehr attraktiv. Ein explosionsartiger Populationsanstieg von Bakterien, die mit den Milben vergesellschaftet sind, konnte beim Verzehr einiger Pilze im Zuge des Populationswachstums der Milben der Familie Anoetidae festgestellt werden. Eine vollstandige und irreversible Zerstorung einiger getesteter Pilze konnte als Folge des Abweidens durch die Milben beobachtet werden.
Journal Article•
TL;DR: In this paper, a simple spin system with two ground states and no symmetry was shown to control low-temperature systems near first-order phase transitions by a straightforward renormalization group argument.
Abstract: On an example of a simple spin system with two ground states and no symmetry, we show how to control low-temperature systems near first-order phase transitions by a straightforward renormalization group argument. The method, as opposed to the Pirogov-Sinai approach, also works for complex Hamiltonians.
TL;DR: In this paper, it was found that the major part of the X-ray line broadening is strain broadening probably caused by lattice defects and growth stacking faults, which decreases in the direction from the substrate to the free surface in textured coatings with low or medium nitrogen contents.
TL;DR: Peroxisomes and their metabolites the plasmalogens were visualized in chorionic villi by quick and simple procedures and may contribute to early prenatal diagnosis of peroxisomal disorders.
Abstract: Peroxisomes and their metabolites the plasmalogens were visualized in chorionic villi by quick and simple procedures. Villi were stained and mounted in toto, and can also be embedded. These methods may contribute to early prenatal diagnosis of peroxisomal disorders (Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum's disease a.o.).
TL;DR: In this paper, the authors measured the refractive index of the ternary compound Hg1-xCdxTe over a large energy region for several alloy compositions x between x = 0.18 and 1.0 at room and liquid nitrogen temperatures.
Abstract: The refractive index of the ternary compound Hg1–xCdxTe is measured over a large energy region for several alloy compositions x between x = 0.18 and 1.0 at room and liquid nitrogen temperatures. The experimental results are compared with two theoretical models and with the Sellmeir equation. The analytical expression describing the compositional dependence of the refractive index is derived by fitting the compositional dependence of Sellmeir coefficients.
Der Brechungsindex der ternaren Verbindung Hg1–xCdxTe wird uber einen weiten Energiebereich fur einige Legierungszusammensetzungen x zwischen x = 0,18 und 1,0 bei Zimmertemperatur und der Temperatur des flussigen Stickstoffs gemessen. Die experimentellen Ergebnisse werden mit zwei theoretischen Modellen und mit der Sellraeiergleichung verglichen. Ein analytischer Ausdruck, der die Zusammensetzungsabhangigkeit des Brechungsindex beschreibt, wird dureh Anpassung der Zusammensetzungsabhangigkeit der Sellmeirkoeffizienten abgeleitot.
TL;DR: A significantly increased N-acetyl-beta-glucosaminidase activity in serum correlated positively with glycated protein but not with the development of retinopathy, as well as between blood pressure and albuminuria.
TL;DR: In this paper, the authors used the time-temperature-superposition principle to obtain master curves for star-like poly (oxypropylene) molecules and crosslinked them with 4,4′-diphenylmethane diisocyanate in one stoichiometric and several non-stochastic reactions.
Abstract: Starlike poly (oxypropylene) molecules (M=2630 resp. 710 g/mol), each with three OH-end-groups, are crosslinked with 4,4′-diphenylmethane diisocyanate in one stoichiometric and several nonstoichiometric reactions. Dynamic mechanical (frequency 10−4 to 102 Hz) and also some dielectric (10−2 to 106 Hz) measurements were made on these networks in a wide temperature range. The time-temperature-superposition principle was used to obtain master curves. Two large relaxation processes were detected (separated by many decades of frequency in some samples). The high frequency process seems to correspond to the glass-rubber transition in linear polymers, the low frequency process is probably due to the relaxation of “dangling chains”.
TL;DR: This work investigates the similarities and differences between usual and local k -colorings, and the results presented in the paper give a general insight to the nature of local coloring.
TL;DR: It is proved that three decision problems related to diagrams are NP-complete.
Abstract: A diagram is an undirected graph corresponding to the covering relation of a finite poset. We prove that three decision problems related to diagrams are NP-complete.
TL;DR: The finite element analysis of a cascade flow problem with a given velocity circulation round profiles is presented and the convergence of the method both for polygonal and nonpolygonal domains is studied, including the effect of numerical integration.
Abstract: The finite element analysis of a cascade flow problem with a given velocity circulation round profiles is presented. The nonlinear problem for the stream function with nonstandard boundary conditions is discretized by conforming linear triangular elements. We deal with the properties of the discrete problem and study the convergence of the method both for polygonal and nonpolygonal domains, including the effect of numerical integration.
TL;DR: A strip of partially hydrolyzed poly (2-hydroxyethyl methacrylate) containing 65%-75% H2O was implanted into the anterior eye chamber of 11 Chinchilla rabbits and no pathological changes were found in the iris or in the ciliary body.
Abstract: A strip of partially hydrolyzed poly (2-hydroxyethyl methacrylate) containing 65%-75% H2O was implanted into the anterior eye chamber of 11 Chinchilla rabbits. No pathological changes were found in the iris or in the ciliary body. The pathological findings in the cornea accompanying implantation of a hydrogel strip to the anterior chamber were rare and not significant. The low occurrence of the foreign body giant multinucleate cells was observed on the implant surface 6 months after the implantation. Favorable properties of this hydrogel depend probably on its high water and acidic groups content.
TL;DR: In this article, a two-level iterative method for 3D elasticity problems discretized by quadratic elements is proposed, where the coarse level consists of linear elements.