According to the standard cosmological model, 27 % of the Universe consists of some mysterious dark matter, 68 % consists of even more mysterious dark energy, whereas only less than 5 % corresponds to baryonic matter composed from known elementary particles. The main purpose of this paper is to show that the proposed ratio 27 : 5 between the amount of dark matter and baryonic matter is considerably overestimated. Dark matter and partly also dark energy might result from inordinate extrapolations, since reality is identified with its mathematical model. Especially, we should not apply results that were verified on the scale of the Solar System during several hundreds of years to the whole Universe and extremely long time intervals without any bound of the modeling error.
We derive a curvature identity that holds on any 6-dimensional Riemannian manifold, from the Chern-Gauss-Bonnet theorem for a 6-dimensional closed Riemannian manifold. Moreover, some applications of the curvature identity are given. We also define a generalization of harmonic manifolds to study the Lichnerowicz conjecture for a harmonic manifold "a harmonic manifold is locally symmetric" and provide another proof of the Lichnerowicz conjecture refined by Ledger for the 4-dimensional case under a slightly more general setting., Yunhee Euh, Jeong Hyeong Park, Kouei Sekigawa., and Obsahuje bibliografii
The correlation between baroreflex sensitivity (BRS) and the spectrum component at a frequency of 0.1 Hz of pulse intervals (PI) and systolic blood pressure (SBP) was studied. SBP and PI of 51 subjects were recorded beat-to-beat at rest (3 min), during exercise (0.5 W/kg of body weight, 9 min), and at rest (6 min) after exercise. BRS was determined by a spectral method (a modified alpha index technique). The subjects were divided into groups according to the spectral amplitude of SBP at a frequency of 0.1 Hz. The following limits of amplitude (in mm Hg) were used: very high ≥ 5.4 (VH); high 5.4 > H ≥ 3 (H); medium 3 > M ≥ 2 (M), low < 2 (L). We analyzed the relationships between 0.1 Hz variability in PI and BRS at rest, during the exercise and during recovery in subgroups VH, H, M, L. The 0.1 Hz variability of PI increased significantly with increasing BRS in each of the groups with identical 0.1 Hz variability in SBP. This relationship was shifted to the lower values of PI variability at the same BRS with a decrease in SBP variability. The primary SBP variability increased during exercise. The interrelationship between the variability of SBP, PI and BRS was identical at rest and during exercise. A causal interrelationship between the 0.1 Hz variability of SBP and PI, and BRS was shown. During exercise, the increasing primary variability in SBP due to sympathetic activation was present, but it did not change the relationship between variability in pulse intervals and BRS., N. Honzíková, A. Krtička, Z. Nováková, E. Závodná., and Obsahuje bibliografii
A workable nonstandard definition of the Kurzweil-Henstock integral is given via a Daniell integral approach. This allows us to study the HL class of functions from . The theory is recovered together with a few new results.
A special case of a combinatorial theorem of De Bruijn and Erdős asserts that every noncollinear set of $n$ points in the plane determines at least $n$ distinct lines. Chen and Chvátal suggested a possible generalization of this assertion in metric spaces with appropriately defined lines. We prove this generalization in all metric spaces where each nonzero distance equals $1$ or $2$.