In the frame of advanced studies of coal structure the temperature conditions of coal origin were investigated through thermal stability of aluminum complexes in coal substance. These compounds were discovered by solid-state nuclear magnetic resonance measurements of 27Al as a part of coal substance closely bonded to organic mass of coal. In obtained spectra, Al-hexaphenoxide and Al-tetrahydroxy-diphenoxide complexes were identified. These complexes were further prepared and their thermal stability tested by thermal analysis method. It was found that a) they can originate under room temperature and atmospheric pressure and b) they are thermally stable only up to approximately 85 or 95 °C. As both Al-hexaphenoxide and Al-tetrahydroxy-diphenoxide complexes are the integrated constituents of coal substance it can be deduced that, in the beginning, coal was formed under very mild thermal conditions. As investigated materials, coals and clays from the Czech basins and gagatite from Poland were measured., Pavel Straka and Jana Náhunková., and Obsahuje bibliografii
Whole blood surface tension of 15 healthy subjects recorded by the ring method was investigated in the temperature range from 20 to 40 °C. The surface tension σ as a function of temperature t (°C) is described by an equation of linear regression as σ(t) = (-0.473 t + 70.105) × 10-3 N/m. Blood serum surface tension in the range from 20 to 40 °C is described by linear regression equation σ(t) = (-0.368 t + 66.072) × 10-3 N/m and linear regression function of blood sediment surface tension is σ(t) = (-0.423 t + 67.223) ×10-3 N/m., J. Rosina, E. Kvašňák, D. Šuta, H. Kolářová, J. Málek, L. Krajči., and Obsahuje bibliografii
When exposing the leaf fragments of wheat (cv. Grana) to decreasing temperature, measurements of delayed luminescence allow to conclude lhát the photosynthetic apparatus in the few-days-old leaves is more low temperature sensitive than that in the leaves several days old.
nclusion of natural (glycerol, proline) or synthetic (polyethylene glycol) compatible solutes in the assay medium for phosphoenolpyruvate carboxylase (EC 4.1.1.31) activity at low substrate (phosphoenolpyruvate) levels enhanced the enzymic activity throughout the temperature range tested (11-42 °C). This effect was much more pronounced above 30 °C and, therefore, the optimum for activity was shifted from 27-29 °C to 37-39 °C, a temperature more consistent with the prevailing leaf temperatures during the growing season for C4-plants; there was also a better correlation between activity/temperature profile and the net photosynthetic rate of intact leaves of Cynodon dactylon (L.) Pers., at the temperature range tested.
This paper focuses on the impact of changes in temperature on one bay of St Vitus’ Cathedral in Prague Castle. The objective of the study is to simulate as correctly as possible the distribution of temperatures in the structure, and then to compute the thermal dilatation movements. Theoretical simulation of dilatation movements involves simulating the temperatures in the structure and then computing the displacements. Insolation and changes in air temperature around the structure are included in the temperature simulation. The computed temperature fields are used as a loading for computing the forces and deformations of one bay of St Vitus’ Cathedral. The theoretical deformation values obtained by means of the 3-D finite element model were compared with the measurements. The computed surface temperatures were also confronted with the surface temperatures measured in the interior and on the exterior of the cathedral. The results obtained from the simulations correspond well with the measured surface temperatures and deformations., Pavel Beran, Jiří Máca and Petr Fajman., and Obsahuje bibliografii
The tendency for self-superparasitism and it's effects on the quality of the parasitoid Ooencyrtus pityocampae (Mercet) (Hymenoptera: Encyrtidae) in parasitizing a new laboratory host, Philosamia ricini (Danovan) (Lepidoptera: Saturniidae), were investigated. In this study, female parasitoids of various ages (1-, 3- and 5-day-old) were tested individually. Parasitoids were provided with 1-day-old P. ricini eggs at ratios of 5, 10, 20, 30 and 40 host eggs per wasp. The tendency to superparasitize was dependent on the female's age and host density. Five-day-old females showed a strong tendency to superparasitize at low host densities. The development time of wasps in superparasitized eggs was longer than that of wasps in singly parasitized eggs. The size and longevity of adult parasitoids decreased significantly with superparasitism. This work contributes to the development of an efficient mass rearing and laboratory rearing of the parasitoid O. pityocampae using a new host., Hilal Tunca, Maurane Buradino, Etty-Ambre Colombel, Elisabeth Tabone., and Obsahuje bibliografii
Tento článek se věnuje historickému kontextu vzniku a přijetí teorému Cauchyho-Kowalevské a teorému Noetherové, dvou jedinečných výsledků, které zásadně ovlivnily moderní matematiku i matematickou a teoretickou fyziku. Autorkami těchto teorémů jsou dvě ženy, Sofie Kowalevská a Emmy Noetherová, které si v době, kdy ženy jen stěží dosahovaly vyššího vzdělání, svým talentem, houževnatostí a úsilím dokázaly vybojovat místo ve vědeckém světě a navždy se zapsaly do historie přírodních věd., The article covers the historical context ot the establishment and recognition of the Cauchy-Kowalevsky theorem and Noether theorem, two unique research results, which have essentially influenced modern mathematics, and mathematical and theoretical physics. The authors of theorems are two women, Sofie Kowalevsky and Emmy Noether who in a time when women barely reached higher education, achieved positions in the scientific world and forever influenced the history of natural sciences., Eliška Beránková., and Obsahuje bibliografii