In presented work natural expanded vermiculite was used as a starting material for synthesis of Fe-doped catalysts. Material was modified with increasing amount of Fe by ion-exchange and precipitation of iron oxide. Composite materials were characterized with respect to their structure (X-ray diffraction, Infrared spectra using Diffuse Reflectance), agglomeration state of Fe (Ultraviolet-Visible spectra using Diffuse Reflectance) and chemical composition. Activity in H2O2 decomposition as well as in phenol oxidation was studied in liquid phase at atmospheric pressure and temperature up to 70 °C. It was shown that doping with Fe increases catalytic activity. However, excess of iron resulted in formation of undesired side-products., Agnieszka Węgrzyn, Lucjan Chmielarz, Paweł Zjeżdżalka, Magdalena Jabłońska, Andrzej Kowalczyk, Agata Żelazny, Manuel Vázquez Sulleiro and Marek Michalik., and Obsahuje bibliografii
This article offers a model, based on the physical conditions of articulation, for the relation between Sumerian and Akkadian stops. Other models can be discounted with a high probability. It is further argued, that the use of signs in older Akkadian should not be interpreted only from one of the two languages involved. From this point of view, a probably (if not fully provable) theory for the Akkadian š and its Sumerian counterparts is developed.
Vision is a fascinating example of the interaction of a biological system with the outside world. The first step of translating electromagnetic energy into a biologically recognizable signal involves the phototransduction cascade in retinal photoreceptor cells. Phototransduction is the best studied example of a GTP binding protein (G protein)- coupled signal transduction pathway. A great body of knowledge about phototransduction has been established in the past several decades but there are still many unanswered questions, particularly about photoresponse recovery and adaptation. The purpose of this review is to outline the events following photon absorption by vertebrate photoreceptors, to demonstrate the great complexity of the phototransduction cascade mechanisms, and to point out some of the controversies arising from recent fmdings in the field of visual transduction.
The vertical activity of small mammals was studied in Central Bohemia, the Czech Republic, from 2003 to 2005. In total, 424 individuals were captured by the CMR technique, in live traps placed at ground level or in trees at heights of 1 and 2 m. The most commonly captured was the yellow-necked mouse, Apodemus flavicollis (96.7 %). Other species captured in the trees were: the common dormouse, Muscardinus avellanarius and the pygmy shrew, Sorex minutus</i. Although mice captures on the ground (considered as 100 %) prevailed significantly over those in trees (84.2 % and 77.9 % at 1 and 2 m, respectively), vertical activity was still quite extensive. In the peak abundance year, mice visited trees more frequently than in the year with lower abundance. There was no clear seasonal variation in vertical activity during the May–October period. No significant difference between male and female vertical activity was found. There was a slight but non-significant positive relation between the weight of an individual and the frequency of its arboreal captures. Any preference for climbing a particular tree species was not found. Our results clearly demonstrate that tree climbing by the yellow-necked mouse represents an important component of its movement activities and this fact should be considered in future studies of its ecology.
The great capricorn beetle or Cerambyx longicorn (Cerambyx cerdo, Linnaeus, 1758) is an internationally protected umbrella species representing the highly diverse and endangered fauna associated with senescent oaks. For the conservation and monitoring of populations of C. cerdo it is important to have a good knowledge of its microhabitat requirements. We investigated determinants and patterns of C. cerdo distribution within individual old, open-grown oaks. Trees inhabited by this species were climbed, and the number of exit holes and environmental variables recorded at two sites in the Czech Republic. Distribution of exit holes in relation to height above the ground, trunk shading by branches, orientation in terms of the four cardinal directions, diameter, surface and volume of inhabited tree parts were investigated. This study revealed that the number of exit holes in the trunks of large open-grown oaks was positively associated with the diameter of the trunk and openness and negatively with height above the ground, and the effects of diameter and openness changed with height. The number of exit holes in the surface of a trunk was also associated with the cardinal orientation of the surface. Approximately half of both C. cerdo populations studied developed less than 4 m and approximately a third less than 2 m above the ground. This indicates that most C. cerdo develop near the ground. Active management that prevents canopy closure is thus crucial for the survival of C. cerdo and searching for exit holes is an effective method of detecting sites inhabited by this species., Jan Albert, Michal Platek, Lukas Cizek., and Obsahuje seznam literatury
A set $S$ of vertices in a graph $G$ is called a paired-dominating set if it dominates $V$ and $\langle S\rangle $ contains at least one perfect matching. We characterize the set of vertices of a tree that are contained in all minimum paired-dominating sets of the tree.
Frontal auditory evoked potentials (FAEPs) obtained as a response to the warning auditory stimulus of a contingent negative variation task from depth electrodes were investigated. The second, imperative stimulus was visual. Thirteen epileptic patients participated in the study. Records from 20 electrodes of 10 patients exhibited signs of local generation. They were localized in the motor cortices (7 cases), in the superior, medial, and inferior frontal gyri (7 cases), in the cingulate gyrus (5 cases), and in the nucleus caudatus (1 case). A typical FAEP from these generators consisted of three components: (i) first negative wave peaking at 99±13 ms; (ii) positive wave peaking at 181±21 ms; (iii) second negative wave peaking at 324±63 ms. In 11 generators no evoked activity to visual stimulus was observed; in the remaining 9 generators both auditory and visual stimuli evoked a response. FAEPs with very early onsets (onset latency below 20 ms) were found in three sites in the precentral gyrus., M. Kukleta, B. Turak, J. Louvel., and Obsahuje bibliografii
We consider the theory of very weak solutions of the stationary Stokes system with nonhomogeneous boundary data and divergence in domains of half space type, such as $\mathbb R^n_+$, bent half spaces whose boundary can be written as the graph of a Lipschitz function, perturbed half spaces as local but possibly large perturbations of $\mathbb R^n_+$, and in aperture domains. The proofs are based on duality arguments and corresponding results for strong solutions in these domains, which have to be constructed in homogeneous Sobolev spaces. In addition to very weak solutions we also construct corresponding pressure functions in negative homogeneous Sobolev spaces.