Exchange-correlation kernels for excited states in solids

The performance of several common approximations for the exchange-correlation kernel within time-dependent density-functional theory is tested for elementary excitations in the homogeneous electron gas. Although the adiabatic local-density approximation gives a reasonably good account of the plasmon dispersion, systematic errors are pointed out and traced to the neglect of the wavevector dependence. Kernels optimized for atoms are found to perform poorly in extended systems due to an incorrect behavior in the long-wavelength limit, leading to quantitative deviations that significantly exceed the experimental error bars for the plasmon dispersion in the alkali metals.Comment: 7 pages including 5 figures, RevTe

Assessment of threats and protection methods of xerothermic grasslands of Festuco-Brometea class in Stawska Gora nature reserve

The study objective is to assess the threats and protection methods of xerothermic grasslands of Festuco-Brometea class and other rare and protected plant species in Stawska Góra nature reserve. The xerothermic grasslands under study are threatened by the lack of grazing, biocenotic evolution and accumulation of dead organic matter, which leads to succession changes in the natural habitat (secondary succession). The cutting of shrubs improved the shrub and tree-understory expansion index but brought only short-term results. The pasturage led to the improvement of parameters such as native expansive species of herbaceous plants, shrub and tree-understory expansion, and dead organic matter, which creates good conditions for the generative reproduction of xerothermic plants such as Carlina onopordifolia