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Kamień Pomorski, Poland

The indirect Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling between on-site magnetic impurities is studied for two kinds of graphene nanoflakes consisting of approximately 100 carbon atoms, posessing either zigzag or armchair edge. The tight-binding Hamiltonian with Hubbard term is used in non-perturbative calculations of coupling between the impurities, placed at the edge of the structure. In general, for zigzag-edged nanoflakes a pronounced coupling robust against charge doping is found, while for armchair-edged structures the interaction is weaker and much more sensitive to charge doping. Also the distance dependence of indirect exchange differs significantly for both edge forms. Source

Rudolf B.,University of Odz | Salmain M.,Ecole Nationale Superieure de Chimie de Paris | Haquette P.,Ecole Nationale Superieure de Chimie de Paris | Stachowicz M.,University of Warsaw | Wozniak K.,University of Warsaw
Applied Organometallic Chemistry | Year: 2010

Owing to their unique properties, ferrocene compounds are gaining increasing interest for biological applications, particularly as enzyme inhibitors. Phosphonate derivatives including a ferrocenyl moiety were synthesized by reaction of dimethyl- and diphenylphosphite with ferrocenyl methyl maleimide. The ferrocenyl diphenyl phosphonate complex was characterized by X-ray diffraction. The ability of these organometallic compounds to inhibit the enzymatic activity of the serine esterases acetyland butyrylcholinesterase was investigated. It appeared that the new ferrocenyl phosphonates inhibited both enzymes by competitive, mixed or non competitve mechanisms with inhibition constants in the range 35-1000 μM. Both compounds also behave as slow time-dependent inactivators of butyrylcholinesterase. The presence of the ferrocenyl entity seems then to have a dramatic effect on the biochemical behavior of the systems. Copyright © 2010 John Wiley & Sons, Ltd. Source

Zanin R.,Intitut de Fisica dAltes Energies | Mazin D.,Intitut de Fisica dAltes Energies | Colin P.,Max Planck Institute | Cortina J.,Intitut de Fisica dAltes Energies | And 6 more authors.
Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011 | Year: 2011

The Crab Pulsar Wind Nebula is the best studied source of γ-ray astrophysics. The contribution of the various soft radiation fields to the Inverse Compton component of its high energy emission, the strenght of the internal magnetic field and the maximum energies reached by primary electrons are however still matter of study. The MAGIC stereoscopic system recorded almost 50 hours of Crab Nebula data in the last two years, between October 2009 and April 2011. Analysis of this data sample using the latest improvements in the MAGIC stereo software provided an unprecedented differential energy spectrum spanning three decades in energy, from 50 GeV up to 45 TeV. At low energies, the MAGIC results, combined with the Fermi/LAT data, yield a precise measurement of the Inverse Compton peak. In addition, we present light curves of the Crab Nebula at different time scales, including a measurement simultaneous to one of the Crab Nebula flares recently detected by both Fermi/LAT and AGILE. Using the MAGIC spectrum together with multiwavelength data, we discuss the implications for the modeling of the Crab Nebula. Source

Live specimens of Fallacia helensis (Schulz) D.G. Mann were recorded in the silt of a plant settling tank that purifies water (ground and surface) drained from a brown coal mine. In Poland the species had previously been identified only in fossil material from the Pleistocene and Holocene (Marciniak 1973, Marciniak & Przybylowska-Lange 1977). Morphometric data and an ecological analysis, including data on associated diatom species, are presented. Source

Degirmendzic J.,University of Odz | Kozuchowski K.,Branch of the University of odz in Tomaszow Mazowiecki
Quaestiones Geographicae | Year: 2015

The article presents the results of the analysis of precipitation in Poland associated with cyclones moving from the Mediterranean Sea to East-Central Europe (Mediterranean Cyclonal Precipitation - MCP). The MCP accounts for about 10% of the total amount of precipitation in Poland. Average daily sum of MCP constitutes approximately 150% of daily amount of all precipitation in Poland. The MCP amount reaches its maxima at the end of April and in the mid-August. The highest MCP occurs in the Carpathians and the Sudetes as well as over stripes of land extending northward and covering the central-western and eastern parts of the country. In the years 1958-2008, the mean annual MCP was characterized by a significant decreasing trend - the MCP sum reduced by 29 mm, i.e. ca. 42% of its multiannual value. © 2015 Faculty of Geographical and Geological Sciences, Adam Mickiewicz University. Source

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