Еколого-ценотичні особливості рідкісних видів спонтанної флори Національного дендрологічного парку “Софіївка” НАН України

An ecological and coenotic evaluation of four rare species of spontaneous flora of the National dendrological park Sofievka of the NAS of Ukraine – Tulipa quercetorum Klokov et Zoz, Allium ursinum L., Euonymus nana M. Bieb., Scopolia carniolica Jacq were carried out. It was determined the affiliation of the communities with the participation of studied species to the corydaletosum cavae subassociation of the Isopyro thalictroidis-Carpinetum Onyshchenko 1998 association. According to the results phytoindicative assessment it was revealed that communities with rare species are on the border or outside the borders of the eco logical amplitude of the association. The major factors of ecological differentiation of the communities were determined. The measures for effective protection of the studied species in conditions of the park were proposed.Проведено еколого-ценотичну оцінку чотирьох рідкісних представників спонтанної флори Національного дендрологічного парку “Софіївка” НАН України – Tulipa quercetorum Klokov et Zoz, Allium ursinum L., Euonymus nana M. Bieb., Scopolia carniolica Jacq. Установлено належність угруповань з їх участю до субасоціації Corydaletosum cavae асоціації Isopyro thalictroidis-Carpinetum Onyshchenko 1998. За результатами фітоіндикаційної оцінки виявлено, що угруповання за участю рідкісних видів перебувають на межі або за межею екологічної амплітуди асоціації. Виділено провідні чинники екологічної диференціації угруповань. Запропоновано заходи з ефективної охорони досліджених видів в умовах дендропарку

Finite-temperature Fermi-edge singularity in tunneling studied using random telegraph signals

We show that random telegraph signals in metal-oxide-silicon transistors at millikelvin temperatures provide a powerful means of investigating tunneling between a two-dimensional electron gas and a single defect state. The tunneling rate shows a peak when the defect level lines up with the Fermi energy, in excellent agreement with theory of the Fermi-edge singularity at finite temperature. This theory also indicates that defect levels are the origin of the dissipative two-state systems observed previously in similar devices.Comment: 5 pages, REVTEX, 3 postscript figures included with epsfi

Modeling vacancies and hydrogen impurities in graphene: A molecular point of view

We have followed a "molecular" approach to study impurity effects in graphene. This is thought as the limiting case of an infinitely large cluster of benzene rings. Therefore, we study several carbon clusters, with increasing size, from phenalene, including three benzene rings, up to coronene 61, with 61 benzene rings. The impurities considered were a chemisorbed H atom, a vacancy, and a substitutional proton. We performed HF and UHF calculations using the STO-3G basis set. With increasing cluster size in the absence of impurities, we find a decreasing energy gap, here defined as the HOMO-LUMO difference. In the case of H chemisorption or a vacancy, the gap does not decrease appreciably, whereas it is substantially reduced in the case of a substitutional proton. The presence of an impurity invariably induces an increase of the density of states near the HOMO level. We find a zero mode only in the case of a substitutional proton. In agreement with experiments, we find that both the chemisorbed H, the substitutional proton, and the C atom near a vacancy acquire a magnetic moment. The relevance of graphene clusters for the design of novel electronic devices is also discussed.Comment: to appear in Phys. Lett.

Ecological and coenotic peculiarities of the rare species of spontaneous flora of the National Dendrological Park Sofiyivka of the NAS of Ukraine

An ecological and coenotic evaluation of four rare species of spontaneous flora of the National dendrological park Sofievka of the NAS of Ukraine — Tulipa quercetorum Klokov & Zoz, Allium ursinum L., Euonymus nana M. Bieb., Scopolia carniolica Jacq were carried out. It was determined the affiliation of the communities with the participation of studied species to the corydaletosum cavae subassociation of the Isopyro thalictroidis-Carpinetum Onyshchenko 1998 association. According to the results phytoindicative assessment it was revealed that communities with rare species are on the border or outside the borders of the eco logical amplitude of the association. The major factors of ecological differentiation of the communities were determined. The measures for effective protection of the studied species in conditions of the park were proposed