The concept of rank of a commutative cancellative semigroup is extended to all commutative semigroups S by defining rank S as the supremum of cardinalities of finite independent subsets of S. Representing such a semigroup S as a semilattice Y of (archimedean) components Sα, we prove that rank S is the supremum of ranks of various Sα. Representing a commutative separative semigroup S as a semilattice of its (cancellative) archimedean components, the main result of the paper provides several characterizations of rank S; in particular if rank S is finite. Subdirect products of a semilattice and a commutative cancellative semigroup are treated briefly. We give a classification of all commutative separative semigroups which admit a generating set of one or two elements, and compute their ranks.
Hemodynamics in the distal end-to-side anastomosis is related to early development of intimal hyperplasia and bypass failure. In this study we investigated the effect of diameter ratios between the target artery and the bypass at three different angles of the connection. The pulsatile flow field was visualized using particle image velocimetry in transparent models with three different angles of the connection (25°, 45°, 60°) and the diameter ratio between the bypass and the target artery was 4.6 mm : 6 mm, 6 mm :
6 mm, and 7.5 mm : 6 mm. Six parameters including location and oscillation of the stagnation point, local energy dissipation, wall shear stress (WSS), oscillatory shear index, spatial and temporal gradient of WSS and their distribution in the target artery were calculated from the flow field. In the wider bypass, the stagnation point oscillated in a greater range and was located more proximal to the anastomosis. Energy dissipation was minimal in a wider bypass with a more acute angle. The maximum WSS values were tree times greater in a narrow bypass and concentrated in a smaller circular region at the floor of the anastomosis. The oscillatory shear index increased with wider bypass and more acute angle. The maximum of spatial gradient of WSS concentrated around the floor and toe of the anastomosis and decreased with more acute angle and wider bypass, the temporal gradient of WSS was stretched more towards the side wall. Greater bypass to target vessel ratio and more acute anastomosis angle promote hemodynamics known to reduce formation of intimal hyperplasia.
Suppose that A is a real symmetric matrix of order n. Denote by m_{A}(0) the nullity of A. For a nonempty subset α of {1, 2,..., n}, let A(α) be the principal submatrix of A obtained from A by deleting the rows and columns indexed by α. When m_{A(\alpha )}(0) = m_{A}(0)+|α|, we call α a P-set of A. It is known that every P-set of A contains at most \left \lfloor n/2 \right \rfloorelements. The graphs of even order for which one can find a matrix attaining this bound are now completely characterized. However, the odd case turned out to be more difficult to tackle. As a first step to the full characterization of these graphs of odd order, we establish some conditions for such graphs G under which there is a real symmetric matrix A whose graph is G and contains a P-set of size (n − 1)/2., Zhibin Du, Carlos M. da Fonseca., and Obsahuje seznam literatury
The article introduces the results achieved in the creation of feasible assemblies of NdFeB magnets assembled following an already published design of a practical arrangement of magnets derived from an ideal magnetization pattern, leading to the strongest possible stray field at a remote point. It presents a method of the implementation of these assembled sets and the relevant measured dependences of magnetic induction By = f(y) and By = f(x) including their comparison with already published dependences determined by a simulation. It further presents similar dependences of magnetic induction found in the case of a trial magnetic circuit with large blocks from NdFeB magnets, and these dependences are compared both with the mentioned computer-determined dependences and the dependences measured with the corresponding implemented assembly of magnets., Václav Žežulka and Pavel Straka., and Obsahuje bibliografii
Although research to date has helped in important ways to shed light on the penetration of Burke’s Enquiry into the German-language area, a comprehensive treatment of this reception as a process distinguished not only by changes over time, but also characterized by regional variations, remains lacking. Based on the lectures on aesthetics by August Gottlieb Meißner (1753–1807) at Prague University in the late eighteenth and early nineteenth centuries, the paper seeks to illuminate this underexposed regional aspect. The first phase of the reception of the Enquiry took place especially in Berlin immediately after its publication in London in 1757. The second phase can be located mainly in the northern maritime centres of German culture, particularly Königsberg, Riga, Hamburg as well as Copenhagen. Christian Garve’s translation, published anonymously by Hartknoch in Riga in 1773, and Kant’s Critique of Judgement (1790) constitute two peaks of north-German interest in Burke’s Enquiry. The intense reception of the Critique of Judgement within German aesthetics around and after 1800 subsequently led to the polemic with the British author becoming a part of Idealist interpretations for the next few decades. Outlining the three centres (and the three corresponding phases) of the German reception of Burke’s Enquiry begs the question which of them should be connected with Meißner’s remarks concerning Burke’s ideas. Leipzig is presented as another important German-language centre disseminating knowledge of Burke’s Enquiry, especially in the first half of the Seventies, moreover the decisive intermediary for the penetration of the Enquiry into the south-German Roman Catholic areas, Prague in particular.
Arthur Prior’s logic was influenced, among others, by logicians from the Lvov-Warsaw school. This paper introduces the impact Leśniewski’s Ontology had on Prior’s logical system. The paper describes the main characteristics of Leśniewski’s Ontology, Prior’s logical system and the manner in which Prior became acquainted with Leśniewski’s logical system. Since Leśniewski was no longer alive when Prior began to develop his logical system and Leśniewski’s papers were not easily available to Prior, this paper also includes Prior’s interpretation of Leśniewski’s logical system which did not always correspond to Leśniewski’s original ideas., Logika Arthura Priora byla ovlivněna mimo jiné i logiky ze školy ve Lvově-Varšavě. Tento článek představuje dopad Leśniewského ontologie na logický systém Prior. Článek popisuje hlavní charakteristiky Leśniewského ontologie, logického systému Prior a způsob, jakým se Prior seznámil s Leśniewského logickým systémem. Vzhledem k tomu, že Leśniewski už nebyl naživu, když Prior začal rozvíjet svůj logický systém a Leśniewskiho dokumenty nebyly Prioritě snadno dostupné, tento dokument zahrnuje také Prorovu interpretaci Leśniewského logického systému, který ne vždy odpovídal Leśniewského původním myšlenkám., and Zuzana Rybaříková
Studie Marty Hulkové se zabývá rozšířením repertoáru hudební skladatelů na pražském dvoře císaře Rudolfa II. v historickém prostoru Horních Uher v době jeho vlády., Marta Hulková., Rubrika: Studie, and Slovenské resumé na s. 157, anglický abstrakt na s. 133.
Ornithologists in Finland recorded the autumn migration of the Red Admiral butterfly, Vanessa atalanta (L.). In the best year, 1998, 1240 migrants were counted from a bird tower in September. That is, half a million butterflies migrated over a 100-km front. The butterflies were flying above forests riding on cool northerly winds. Radar indicated that a large proportion migrated at high elevations outside the visible range. These records help to resolve an "evolutionary puzzle" of why migrant butterflies and moths travel to northern latitudes when their offspring have limited possibilities of returning south. Until now, the only butterfly for which a high-elevation return migration on northerly winds is known is the American Monarch Danaus plexippus (L.).
Progressive microwave power saturation (P1/2) measurements have been performed on the tyrosine D radical (YD*) of photosystem II (PSII) in order to examine its relaxation enhancement by the oxygen-evolving complex (OEC) poised to the reduced S-1 and S-2 oxidation states by NO treatment. Analysis of the power saturation curves showed that the S-1 oxidation state of the OEC does not enhance the relaxation of YD*: it therefore possesses a diamagnetic ground state. In contrast, the Mn(II)-Mn(III) multiline electron paramagnetic resonance (EPR) signal characteristic of the S-2 oxidation state of the OEC was shown to provide a relaxation enhancement pathway for YD*, however less efficient relative to the one provided by the S2-state multiline EPR signal. We also examined the YD * relaxation enhancement characteristics of the EPR-silent oxidation state produced after brief (1-5 min) dark incubation at 0°C of a PSII sample poised to the EPRactive S-2 state. This EPR-silent oxidation state denoted as "0°C incubation" state was shown to possess remarkably similar P1/2 values with the EPR-active S-2 state in the overall examined temperature range (6-20 K). In addition, these values remained unchanged after successive cycles of the OEC between the EPR-active S-2 state and the "0°C incubation" state. The data presented in this work point to the conclusion that the "0°C incubation" state is indeed an S-2 oxidation state with half-integer spin.