scispace - formally typeset
Search or ask a question

Showing papers by "Charles University in Prague published in 1995"


Journal ArticleDOI
TL;DR: The construction of the first complete genetic linkage map of the laboratory rat is reported, identifying 432 markers that show polymorphisms between the SHR and BN rat strains and mapped them in a single SHR × BN F2 intercross.
Abstract: We report the construction of the first complete genetic linkage map of the laboratory rat. By testing 1171 simple sequence length polymorphisms (SSLPs), we have identified 432 markers that show polymorphisms between the SHR and BN rat strains and mapped them in a single (SHR × BN) F2 intercross. The loci define 21 large linkage groups corresponding to the 21 rat chromosomes, together with a pair of nearby markers on chromosome 9 that are not linked to the rest of the map. Because 99.5% of the markers fall into one of the 21 large linkage groups, the maps appear to cover the vast majority of the rat genome. The availability of the map should facilitate whole genome scans for genes underlying qualitative and quantitative traits relevant to mammalian physiology and pathobiology.

478 citations


Journal ArticleDOI
TL;DR: In this article, the standard notion of non-Abelian duality in string theory is generalized to the class of σ-models admitting a Poisson-Lie-like 3ymmetry.

443 citations


Journal Article
TL;DR: In this article, the object was illuminated with nearly incoherent light passing through holes in one side of a rotating scanning disk (Nipkow wheel) which was imaged by the objective into the object plane.
Abstract: Reflected-light microscopy of semitransparent material, such as unstained nervous tissue, is usually unsatisfactory because of low contrast and light scattering. In a new microscope both the object plane and the image plane were scanned in tandem so that only light reflected from the object plane was included in the image. The object was illuminated with nearly incoherent light passing through holes in one side of a rotating scanning disk (Nipkow wheel) which was imaged by the objective into the object plane. Reflected-light images of these spots were conducted to the opposite side of the same disk. Light could pass from the source to the object plane, and from the object to the image plane, only through optically congruent holes on opposite side of the rotating disk. The image obtained had better contrast and sharpness for some semitransparent material than possible in usual reflected-light microscopy.

363 citations


Journal ArticleDOI
TL;DR: Clay has always played a major role in human life as discussed by the authors, mainly because of their wide-ranging properties, high resistance to atmospheric conditions, geochemical purity, easy access to their deposits near the earth's surface and low price.

307 citations


Journal ArticleDOI
TL;DR: In this article, the dynamics of solvation of an excited chromophore in pure water and in a restricted space with a limited number of water molecules have been studied using femtosecond fluorescence upconversion and time-correlated single-photon counting techniques.
Abstract: The dynamics of solvation of an excited chromophore in pure water and in a restricted space with a limited number of water molecules have been studied The time-dependent Stokes shift of Coumarin 480 (C480) and Coumarin 460 (C460) were measured using femtosecond fluorescence upconversion and time-correlated single-photon-counting techniques The system with a limited number of water molecules was an inclusion complex of Coumarin dyes with γ-cyclodextrin (γCD) The results of molecular dynamics simulations are compared with the observed solvent response in pure water and in the γCD cavity The observed relaxation times range from <100 fs to 12 ns Solvation of C480 in pure water is observed to occur with time constants of <50 and 310 fs In sharp contrast with the solvation response in pure water, in the case of the C480/γCD inclusion complex, additional long solvation time constants of 13, 109 and 1200 ps are observed The stoichiometry, structure and dynamics of the Coumarin/γCD complexes are also discussed

256 citations


Journal ArticleDOI
TL;DR: The data suggest that granule cell bursting activity is at least in part a function of compromised synaptic inhibition, since levels of γ‐aminobutyric acid (GABA) blockade that are generally subthreshold for burst induction were epileptogenic in some tissue samples from human epileptic hippocampus.
Abstract: Morphological and electrophysiological techniques were used to examine granule cells and their mossy fiber axons in nine surgically resected hippocampal specimens from temporal lobe epilepsy (TLE) patients. Timm histochemistry showed mossy fiber sprouting into the inner molecular layer (IML) of the dentate in a subset of tissue samples. In slices from five tissue samples, stimulus-induced bursting activity could be induced with a low concentration (2.5 microM) of bicuculline; bursts were sensitive to the N-methyl-D-aspartate (NMDA) blocker, APV. There was a general correlation between such sprouting and experimentally induced hyperexcitability. Fourteen granule cells from five tissue samples were intracellularly stained [with lucifer yellow (LY) or neurobiotin]. Axons from a subset of these neurons showed axon collaterals reaching into the IML, but this axon projection pattern for single cells was not directly correlated with degree of mossy fiber sprouting shown grossly by Timm staining. Electron microscopic examination of intracellularly stained elements showed mossy fiber axon terminals making asymmetric synaptic contacts (including autapses on the granule cell dendrite) with dendritic shafts and spines in both apical and basal domains. These data are consistent with the hypothesis that mossy fiber sprouting provides a structural basis for recurrent excitation of granule cells, but does not provide direct support of the hypothesis that mossy fiber sprouting causes hyperexcitability. The data suggest that granule cell bursting activity is at least in part a function of compromised synaptic inhibition, since levels of gamma-aminobutyric acid (GABA) blockade that are generally subthreshold for burst induction were epileptogenic in some tissue samples from human epileptic hippocampus.

236 citations


Journal ArticleDOI
TL;DR: In this paper, a generalization of the Bongartz lemma for tilting torsion theories in Mod-R is presented. Butler et al. generalize basic results about classical tilting modules and partial tilting module to the infinite dimensional case, over an arbitrary ring R. The methods employed combine classical techniques of representation theory of finite dimensional algebras with new techniques of ∗-modules.

187 citations


Journal ArticleDOI
T. Ahmed1, S. Aid2, a A. Akhundov2, Vladimir Andreev3  +407 moreInstitutions (27)
TL;DR: In this paper, a measurement of the contribution of diffractive interactions to deep-inelastic electron-proton (ep) scattering in the kinematic range 8.5 × 10−4 < Bjorken-x < 0.0133, and 3.7 × 10 −4 < χp <0.043.

163 citations


Journal ArticleDOI
TL;DR: These findings suggest that for both motion-onset and pattern-reversal VEPs the negative peak is attributable to the motion-processing magnocellular pathway and the positive peak to the form-processing parvocellular system.

153 citations


Journal ArticleDOI
01 Jun 1995-Chest
TL;DR: It is concluded that patients with an undiagnosed pleural effusion should be evaluated in an individualized stepwise manner and if malignancy is strongly considered, the initial three steps should be relatively noninvasive and include clinical evaluation and cytologic study.

145 citations


Journal ArticleDOI
TL;DR: In this paper, a duality invariant first order action is constructed on the loop group of a Drinfeld double, which gives at the same time the description of both of the pair of $\sigma$-models related by Poisson-Lie T-duality.
Abstract: A duality invariant first order action is constructed on the loop group of a Drinfeld double. It gives at the same time the description of both of the pair of $\sigma$-models related by Poisson-Lie T-duality. Remarkably, the action contains a WZW-term on the Drinfeld double not only for conformally invariant $\si$-models. The resulting actions of the models from the dual pair differ just by a total derivative corresponding to an ambiguity in specifying a two-form whose exterior derivative is the WZW three-form. This total derivative is nothing but the Semenov-Tian-Shansky symplectic form on the Drinfeld double and it gives directly a generating function of the canonical transformation relating the $\si$-models from the dual pair.

Journal ArticleDOI
TL;DR: In this article, the stability of mechanically isolated flows of non-Newtonian fluids for arbitrary initial disturbances is investigated and the existence and regularity of solutions for small data is discussed.
Abstract: In this paper we clarify and discuss some subtle features concerning the non-Newtonian fluid models which were considered by Malek, Necas and Růžicka.19 We establish new results regarding the stability of the rest state of mechanically isolated flows of such non-Newtonian fluids for arbitrary initial disturbances. We also discuss some results concerning the existence and regularity of solutions for small data. These results are based on a new method, giving convergence almost everywhere of approximations of gradients from boundedness of fraction of the L2-norm of the second and first derivatives, developed by Necas to study existence of solutions (global in time) to a class of partial differential equations.


Journal ArticleDOI
TL;DR: A general algorithm is given and its efficient implementations for specific geometric problems are discussed, for instance for the problem of computing the smallest circle enclosing all butk of the givenn points in the plane, anO(n logn+k3nε) algorithm.
Abstract: We investigate the problem of finding the best solution satisfying all butk of the given constraints, for an abstract class of optimization problems introduced by Sharir and Welzl--the so-calledLP-type problems. We give a general algorithm and discuss its efficient implementations for specific geometric problems. For instance for the problem of computing the smallest circle enclosing all butk of the givenn points in the plane, we obtain anO(n logn+k3n?) algorithm; this improves previous results fork small compared withn but moderately growing. We also establish some results concerning general properties ofLP-type problems.

Journal ArticleDOI
TL;DR: In this article, high-temperature, high-pressure eclogite and garnet pyroxenite occur as lenses in garnet peridotite bodies of the Gfohl nappe in the Bohemian Massif.
Abstract: High-temperature, high-pressure eclogite and garnet pyroxenite occur as lenses in garnet peridotite bodies of the Gfohl nappe in the Bohemian Massif. The high-pressure assemblages formed in the mantle and are important for allowing investigations of mantle compositions and processes. Eclogite is distinguished from garnet pyroxenite on the basis of elemental composition, with mg number 0.75 wt.%, Cr2O3 < 0.15 wt.% and Ni < 400 ppm. Considerable scatter in two-element variation diagrams and the common modal layering of some eclogite bodies indicate the importance of crystal accumulation in eclogite and garnet pyroxenite petrogenesis. A wide range in isotopic composition of clinopyroxene separates [eNd, +5.4 to −6.0; (87Sr/86Sr)i, 0.70314–0.71445; δ18OSMOW, 3.8–5.8%o] requires that subducted oceanic crust is a component in some melts from which eclogite and garnet pyroxenite crystallized. Variscan Sm-Nd ages were obtained for garnet-clinopyroxene pairs from Dobesovice eclogite (338 Ma), Uhrov eclogite (344 Ma) and Nove Dvory garnet pyroxenite (343 Ma). Gfohl eclogite and garnet pyroxenite formed by high-pressure crystal accumulation (±trapped melt) from transient melts in the lithosphere, and the source of such melts was subducted, hydrothermally altered oceanic crust, including subducted sediments. Much of the chemical variation in the eclogites can be explained by simple fractional crystallization, whereas variation in the pyroxenites indicates fractional crystallization accompanied by some assimilation of the peridotite host.

Journal ArticleDOI
TL;DR: Changes in concentrations of cytokines in plasma and in hypothalamic push-pull perfusates of guinea pigs were measured within the 1st hour after intramuscular injections of bacterial lipopolysaccharide or solvent and the method used did not detect any changes in the amount of biologically active IL-1 in hypothalamusates of LPS-treated animals.
Abstract: Changes in concentrations of cytokines in plasma and in hypothalamic push-pull perfusates of guinea pigs were measured within the 1st hour after intramuscular injections of bacterial lipopolysaccharide (LPS; Escherichia coli, 20 micrograms/kg) or solvent (0.9% saline). In control animals injected with solvent, interleukin (IL)-1 and tumor necrosis factor alpha (TNF-alpha) were not detectable in plasma. Only IL-6 was present in picogram quantities. Within 45 min after injection of LPS, the concentrations of IL-1, TNF-alpha, and IL-6 increased in the plasma: by several orders of magnitude for TNF-alpha and about tenfold for IL-G. Picogram amounts of biologically active IL-1 were detected in plasma after injection of LPS. No steady state levels of systemic cytokines were reached during the experimental period. In hypothalamic perfusates of animals injected with the solvent, no IL-1 was detectable. TNF-alpha could be detected at higher concentrations than IL-6. IL-6 was detectable at tenfold lower concentrations than in the plasma. In animals injected with LPS, the hypothalamic concentration of IL-6 started to increase during the period 15-30 min and the concentrations of TNF-alpha during the period 30-45 min after LPS injection. The concentrations of IL-6 increased by 300-400% and did not exceed picogram values. No progressive increase of hypothalamic levels of these cytokines was observed during the time course of the experiment. The method used did not detect any changes in the amount of biologically active IL-1 in hypothalamic perfusates of LPS-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: It is suggested that homocysteine cannot be considered a simple agonist of the kainate or NMDA type of excitatory amino acid receptors, as it elicited minimal, predominantly clonic, and major generalized tonic‐clonic seizures at six different developmental stages, from 7 days to adulthood.
Abstract: Summary: We studied the convulsant action of homocysteine in 211 immature and adult Wistar albino rats. Homocysteine elicited minimal, predominantly clonic, and major generalized tonic-clonic seizures at six different developmental stages, from 7 days to adulthood. Nevertheless, some age-dependent differences in the seizure pattern were apparent. Minimal seizures in immature rats lasted ≤20 min, thus representing an epileptic status, whereas in adult animals these seizures were much shorter, lasting only ≥40 s. In addition, flexion seizures were observed in 7-and 12-day-old rats, only rarely in 15-and 18-day-old animals, and never in the 25-day-old and adult rats. ECoG recordings demonstrated a nearly iso-electric pattern during homocysteine-induced seizures in 7-and 12-day-old rat pups. In older rats, spikes or sharp waves were recorded, but precise electroclinical correlations were poor. The greater sensitivity of younger animals to kainic acid (KA) and N-methyl-D-aspartate (NMDA), as reported previously, was not evident in the case of homocysteine-induced seizures. This observation, together with a different behavioral pattern, suggests that homocysteine cannot be considered a simple agonist of the kainate or NMDA type of excitatory amino acid receptors. The exact mechanism of the convulsant action of homocysteine, both during development and in adulthood, remains to be clarified.

Journal ArticleDOI
TL;DR: In this article, a geometric representation for the Widom-Rowlinson model of interpenetrating spheres is proposed and a simple percolation-based proof of the phase transition is provided.
Abstract: We study the continuum Widom-Rowlinson model of interpenetrating spheres. Using a new geometric representation for this system we provide a simple percolation-based proof of the phase transition. We also use this representation to formulate the problem, and prove the existence of an interfacial tension between coexisting phases. Finally, we ascribe geometric (i.e. probabilistic) significance to the correlation functions which allows us to prove the existence of a sharp correlation length in the single-phase regime.

Journal ArticleDOI
TL;DR: Results indicate that in this family the T-->G point mutation at position 8993 in the mitochondrial ATPase 6 gene is accompanied by structural instability and altered assembly of the enzyme complex, that are both most likely due to changes in the properties of subunit a of the membrane sector part of the ATP-synthase.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated land use and landscape structure changes using the example of an agricultural landscape in central Bohemia and paid particular attention to the great changes which occurred during the 40 years of socialist collectivism.

Journal ArticleDOI
TL;DR: This research presents a novel and scalable approach called “SmartPharm,” which aims to provide real-time information about the safe and effective use of these drugs in the context of clinical practice.
Abstract: MRC Experimental Embryology and Teratology Unit, St. George's Hospital Medical School, Cranmer Terrace, London SW17 ORE, UK; ZEBET, BgW, Diedersd01fer Weg 1, 12277 Berlin, Germany; Sandoz Pharma Limited, Drug Safety Assessment, 4002 Basle, Switzerland; Bristol-Myers Squibb, Pharmaceutical Research Institute, 6000 Thompson Road, Syracuse, NY 13221, USA; 7SmithKline Beecham Consumer Healthcare, StGeorge's Avenue, Weybridge, Surrey KT13 ODE, UK; 8Department of Histology and Emb1yology, 3rd Medical Faculty, Charles University, Ruska 87, 100 00 Prague 10, Czech Republic; Freie University of Berlin, Institute for Toxicology and Emb1yopharmacology, Gmystrasse 5, 1000 Berlin 33, Germany; GlaxoWellcome Research and Development, Genetic and Repl'Oductive Toxicology, Ware, Herts. SG12 ODP, UK,· 11Huntin;;don Research Centre, Department of Toxicology, Huntingdon, Cambs. PElS 6ES, UK; RhOne-Poulenc Rorer, Drug Safety NW 9, 500 Arcola Road, Collegeville, PA 19426-0107, USA; 1•1Rh6ne-Poulenc, Secteur Agro, 06903 Sophia Antipolis Cedex, France; BgVV, Thielallee 88-92, 14191 Berlin, Germany; 15National Institute of Public Health, Department of Environmental Medicine, Geitmyrsveien 75, 0462 Oslo 4, Norway

Journal ArticleDOI
TL;DR: The greatest fixed point of a set functor is proved to be (a) a metric completion and (b) a CPO-completion of finite iterations.

Journal ArticleDOI
TL;DR: The computational complexity of a number of problems concerning induced structures in graphs is studied, and some useful structural theorems concerning induced minors are presented, including a bound on the treewidth of planar graphs that exclude a planar induced minor.
Abstract: The computational complexity of a number of problems concerning induced structures in graphs is studied, and compared with the complexity of corresponding problems concerning non-induced structures. The effect on these problems of restricting the input to planar graphs is also considered. The principal results include: (1) Induced Maximum Matching and Induced Directed Path are NP-complete for planar graphs, (2) for every fixed graphH, InducedH-Minor Testing can be accomplished for planar graphs in time0(n), and (3) there are graphsH for which InducedH-Minor Testing is NP-complete for unrestricted input. Some useful structural theorems concerning induced minors are presented, including a bound on the treewidth of planar graphs that exclude a planar induced minor.

Journal ArticleDOI
TL;DR: Total coelomic fluid of earthworms Eisenia foetida is capable of lysing different mammalian tumor cell lines and this cytolytic activity is different from tumor necrosis factor (TNF)-mediated lysis and is not due to proteolysis.

Journal ArticleDOI
TL;DR: In this paper, a class of simple estimators of the change-point m in a sequence of n independent random variables X1,X n satisfying E(X i ) = θ 0 for i = 1,…,m and E( X i ) was shown to be asymptotically valid.
Abstract: We consider a class of simple estimators of the change-point m in a sequence of n independent random variables X1…,X n satisfying E(X i ) = θ0 for i = 1,…,m and E(X i ) = θ0+δ n for i = m +1,…n. (θ0 and δ n are unknown). We obtain rates of consistency for the estimator, derive its limiting distribution and show that the bootstrap approximation is asymptotically valid. The results are illustrated by some simulations.

Journal ArticleDOI
TL;DR: In this paper, an upwind flux vector splitting finite volume scheme was proposed for the discretization of inviscid first order terms of the system and the finite element approximation of viscous dissipative terms.

Journal ArticleDOI
TL;DR: The heterogeneity of protein structure is a fundamental limitation to the use of such spectral analysis methods, and the underutilization of these data for prediction of secondary structure suggests spectral data could predict a more detailed descriptor.
Abstract: This work provides a systematic comparison of vibrational CD (VCD) and electronic CD (ECD) methods for spectral prediction of secondary structure. The VCD and ECD data are simplified to a small set of spectral parameters using the principal component method of factor analysis (PC/FA). Regression fits of these parameters are made to the X-ray-determined fractional components (FC) of secondary structure. Predictive capability is determined by computing structures for proteins sequentially left out of the regression. All possible combinations of PC/FA spectral parameters (coefficients) were used to form a full set of restricted multiple regressions with the FC values, both independently for each spectral data set as well as for the two VCD sets and all the data grouped together. The complete search over all possible combinations of spectral parameters for different types of spectral data is a new feature of this study, and the focus on prediction is the strength of this approach. The PC/FA method was found to be stable in detail to expansion of the training set. Coupling amide II to amide I' parameters reduced the standard deviations of the VCD regression relationships, and combining VCD and ECD data led to the best fits. Prediction results had a minimum error when dependent on relatively few spectral coefficients. Such a limited dependence on spectral variation is the key finding of this work, which has ramifications for previous studies as well as suggests future directions for spectral analysis of structure. The best ECD prediction for helix and sheet uses only one parameter, the coefficient of the first subspectrum. With VCD, the best predictions sample coefficients of both the amide I' and II bands, but error is optimized using only a few coefficients. In this respect, ECD is more accurate than VCD for alpha-helix, and the combined VCD (amide I' + II) predicts the beta-sheet component better than does ECD. Combining VCD and ECD data sets yields exceptionally good predictions by utilizing the strengths of each. However, the residual error, its distribution, and, most importantly, the lack of dependence of the method on many of the significant components derived from the spectra leads to the conclusion that the heterogeneity of protein structure is a fundamental limitation to the use of such spectral analysis methods. The underutilization of these data for prediction of secondary structure suggests spectral data could predict a more detailed descriptor.

Journal ArticleDOI
TL;DR: The result holds for arbitrary set systems as long as theimal shatter function isO(md) and matches known lower bounds, improving previous upper bounds by a factor.
Abstract: We show that the discrepancy of anyn-point setP in the Euclideand-space with respect to half-spaces is bounded byCdn1/2?1/2d, that is, a mapping ?:P?{?1,1} exists such that, for any half-space ?, ?, |Σp?P???(p)|≤Cdn1/2-1/2d. In fact, the result holds for arbitrary set systems as long as theprimal shatter function isO(md). This matches known lower bounds, improving previous upper bounds by a $$\sqrt {\log n} $$ factor.

Journal ArticleDOI
V. M. Abazov1, Brad Abbott2, M. Abolins3, Bodhraj Acharya4  +499 moreInstitutions (87)
TL;DR: In this paper, the W boson mass in W − ev decays was measured using 1 fb^-1 of data collected with the D0 detector during Run II of the Fermilab Tevatron collider.
Abstract: We present a measurement of the W boson mass in W -> ev decays using 1 fb^-1 of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W -> ev candidate events, we measure M_W = 80.401 +- 0.043 GeV. This is the most precise measurement from a single experiment.

Journal ArticleDOI
TL;DR: In this paper, a semi-infinite three-dimensional Ising system with a rough wall was considered and the effect of roughness on wetting was investigated, and it was shown that roughness enhances wetting.
Abstract: We consider a semi-infinite three-dimensional Ising system with a rough wall to describe the effect of the roughness $r$ of the substrate on wetting. For sufficiently low temperature, we show that the difference of wall free energies $\ensuremath{\Delta}\ensuremath{\tau}\left(r\right)$ of the two phases behaves like $\ensuremath{\Delta}\ensuremath{\tau}\left(r\right)\ensuremath{\approx}r\ensuremath{\Delta}\ensuremath{\tau}\left(1\right)$, implying that roughness enhances wetting for $\ensuremath{\Delta}\ensuremath{\tau}\left(1\right)g0$ and drying for $\ensuremath{\Delta}\ensuremath{\tau}\left(1\right)l0$.