The upper dial-plate of the astronomical clock is an astrolabe controlled by a clockwork mechanism. It represents a stereographic projection of the celestial sphere from its North Pole onto the tangent plane passing through the South Pole. We give a survey of several astronomical mistakes that appeared on this dial throughout centuries., V letošním roce je orloji na Staroměstském náměstí v Praze právě 600 let. Před rokem 1979 byla na jeho astronomickém ciferníku nesprávně zakreslena kruhová oblast astronomické noci. V tomto článku se zmíníme o dalších významných kružnicích, jejichž rozměry a umístění na orloji by se daly ještě zlepšit., Michal Křížek, Pavel Křížek, Jakub Šolc., and Obsahuje bibliografii
Astronomické informace pro profesionály jsou v dnešní době bez problému dostupné v odborných časopisech, databázích naměřených dat, knihách a internetových publikacích. Kde však může získat kvalitní nezkreslené informace širší veřejnost? Televizních astronomických pořadů je jako šafránu, a ty, které zbyly, jsou mnohdy kombinovány s astrologií, věštectvím a jinými pavědami. V rozhlase zůstaly pořady Meteor a Planetárium, ale ty se netýkají jen astronomie. Z ryze astronomických vědecko-populárních časopisů nám zbyl už jediný - Astropis - a doufejme, že přežije i nadále. Většina lidí se proto obrací k internetu. Pro laika je někdy obtížné odlišit kvalitní informace od balastu, a proto přinášíme čtenářům stručný výběr některých webů s hodnotnými astronomickými informacemi. and Petr Kulhánek.
Již podruhé se v bubenečské vile Lanně sešli odborníci zabývající se historickými astronomickými deskami. První setkání se konalo před dvěma lety, kdy se diskutovaly problémy desek sužovaných degradací emulze vlivem dlouhého a často nešetrného skladování - letošní akce se zúčastnilo 44 odborníků z 20 zemí od Mexika až po Čínu. and Petr Skala.
Level of asymmetric dimethylarginine (ADMA) is elevated and endothelial progenitor cells (EPC) and stem cells (SC) are decreased in patients undergoing renal transplantation (Tx) and may contribute to cardiovascular complications. We tested the hypothesis that ADMA, EPC and SC can be influenced with regular physical exercise early after Tx. Blood samples of ADMA, EPC, SC, adipocytokines and metabolic parameters were randomly obtained from 50 transplant patients before and 6 months after exercise program (Group I). Fifty age, sex HLA typing, duration of dialysis and immunosupression regimen-matched non exercising transplant were examined as controls (Group II). After 6 months, in Group I ADMA decreased (3.50±0.45 vs 2.11±0.35 μmol/l, P<0.01) and was lower comparing to Grou II (P<0.01), SC and EPC also decreased (2816±600 vs 2071±480 cells/ml resp. 194±87 to 125±67 cells/ml, P<0.02). Next changes in Group I: adiponectin (P<0.01), leptin (P<0.01), resistin (P<0.02). Visfatin, blood lipids, HbA1c, insulin and blood pressure were also influenced by training program (P<0.05)., V. Teplan, I. Králová Lesná, J. Piťha, A. Mahrová, J. Racek, I. Valkovský, A. Sekerková, M. Štollová., and Obsahuje bibliografii
We complement the recently introduced classes of lower and upper semilinear copulas by two new classes, called vertical and horizontal semilinear copulas, and characterize the corresponding class of diagonals. The new copulas are in essence asymmetric, with maximum asymmetry given by 1/16. The only symmetric members turn out to be also lower and upper semilinear copulas, namely convex sums of Π and M.
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The gob side entry retaining with high water material is often used in coal mines. To study the stress evolution characteristics of surrounding rock and asymmetric support control technology of gob side entry retaining with high water material, the evolution law of stress and deformation of surrounding rock in gob side entry retaining during working face mining is studied by theoretical analysis, numerical simulation and field measurement. According to the stress variation of overlying strata during the mining process of the working face, the mechanical models before and after the basic roof fracture were established respectively. The stress and deformation of the filling body and the roof on the side of the filling body are larger, and the stress and deformation of the solid coal and the roof on the side of solid coal are smaller. The maximum stress is at 3 m away from the roadway. The first weighting step distance is 40 m and the periodic weighting step distance is 30 m. Based on the stress and deformation characteristics of the roadway surrounding, the roadway surrounding support is divided into filling bodyside, solid coal side, and middle part of roadway roof. The asymmetric support technology of "filling body+ double row hydraulic prop+ I-beam+ high-strength pretension anchor cable+ high-strength bolt" is proposed. The field engineering practice shows that the surrounding rock control effect of asymmetric support technology with high water material is good., Qiyuan Shan, Yongli Liu, Tao Li and Zhupeng Jin., and Obsahuje bibliografii
In this paper we prove two results. The first is an extension of the result of G. D. Jones [4]: (A) Every nontrivial solution for \[ \left\rbrace \begin{array}{ll}(-1)^n u^{(2n)} + f(t,u) = 0,\hspace{5.0pt}\text{in} \hspace{5.0pt}(\alpha , \infty ), u^{(i)}(\xi ) = 0, \quad i = 0,1,\dots , n-1, \hspace{5.0pt} \text{and} \hspace{5.0pt}\xi \in (\alpha , \infty ), \end{array}\right.\] must be unbounded, provided $f(t,z)z\ge 0$, in $E \times \mathbb R$ and for every bounded subset $I$, $f(t,z)$ is bounded in $E \times I$. (B) Every bounded solution for $(-1)^n u^{(2n)} + f(t,u) = 0$, in $\mathbb R$, must be constant, provided $f(t,z)z\ge 0$ in $\mathbb R \times \mathbb R$ and for every bounded subset $I$, $f(t,z)$ is bounded in $\mathbb R \times I$.
The nonlinear difference equation (E) xn+1 − xn = anϕn(xσ(n) ) + bn, where (an), (bn) are real sequences, ϕn : −→ , (σ(n)) is a sequence of integers and lim n−→∞ σ(n) = ∞, is investigated. Sufficient conditions for the existence of solutions of this equation asymptotically equivalent to the solutions of the equation yn+1 − yn = bn are given. Sufficient conditions under which for every real constant there exists a solution of equation (E) convergent to this constant are also obtained.