Impact of Aurelia aurita medusae (Cnidaria, Scyphozoa) on the standing stock and community composition of mesozooplankton in the Kiel Bight (western Baltic Sea)

During 5 consecutive summer seasons (1990 to 1994) both Aureliaaurita medusa and mesozooplankton abundances were investigated at 2 stations in the Kiel Bight (western Baltic Sea). Stocks of medusae varied considerably between the years, with median abundance of 1 and 0.3 ind. 100 m-3 in 1990 and 1991, 3 and 4 ind. 100 m-3 in 1992 and 1994, but 9 ind. 100 m-3 in 1993. Significant differences in the mesozooplankton stock and community composition were observed in 1993 when compared with the year of rather low Aurelia abundance (1991). Total zooplankton and copepod numbers both exhibited an inverse relationship with the abundance of medusae and were thus considerably lower in 1993 than in 1991. However, not all copepod species were affected by A. aurita. Pseudo- and Paracalanus spp. and Oithonasimilis showed dramatically reduced stocks in the bloom year when compared with the medusa-poor situation, but no significant changes were found for Centropageshamatus and Acartia spp. Also other zooplankton groups with the exception of bivalve larvae were reduced by the medusae. The differential response of zooplankton to varying abundance of medusae led to a shift in the trophic structure of the zooplankton community. Fine-filter feeders and raptorial feeders were much more important in years when medusae occurred in low densities, whereas coarse-filter feeders dominated in the opposite situation

Impact of Aurelia aurita medusae (Cnidaria, Scyphozoa) on the standing stock and community composition of mesozooplankton in the Kiel Bight (western Baltic Sea)

During 5 consecutive summer seasons (1990 to 1994) both Aureliaaurita medusa and mesozooplankton abundances were investigated at 2 stations in the Kiel Bight (western Baltic Sea). Stocks of medusae varied considerably between the years, with median abundance of 1 and 0.3 ind. 100 m-3 in 1990 and 1991, 3 and 4 ind. 100 m-3 in 1992 and 1994, but 9 ind. 100 m-3 in 1993. Significant differences in the mesozooplankton stock and community composition were observed in 1993 when compared with the year of rather low Aurelia abundance (1991). Total zooplankton and copepod numbers both exhibited an inverse relationship with the abundance of medusae and were thus considerably lower in 1993 than in 1991. However, not all copepod species were affected by A. aurita. Pseudo- and Paracalanus spp. and Oithonasimilis showed dramatically reduced stocks in the bloom year when compared with the medusa-poor situation, but no significant changes were found for Centropageshamatus and Acartia spp. Also other zooplankton groups with the exception of bivalve larvae were reduced by the medusae. The differential response of zooplankton to varying abundance of medusae led to a shift in the trophic structure of the zooplankton community. Fine-filter feeders and raptorial feeders were much more important in years when medusae occurred in low densities, whereas coarse-filter feeders dominated in the opposite situation

Nodal-line semimetals from Weyl superlattices

The existence and topological classification of lower-dimensional Fermi surfaces is often tied to the crystal symmetries of the underlying lattice systems. Artificially engineered lattices, such as heterostructures and other superlattices, provide promising avenues to realize desired crystal symmetries that protect lower-dimensional Fermi surface, such as nodal lines. In this work, we investigate a Weyl semimetal subjected to spatially periodic onsite potential, giving rise to several phases, including a nodal-line semimetal phase. In contrast to proposals that purely focus on lattice symmetries, the emergence of the nodal line in this setup does not require small spin-orbit coupling, but rather relies on its presence. We show that the stability of the nodal line is understood from reflection symmetry and a combination of a fractional lattice translation and charge-conjugation symmetry. Depending on the choice of parameters, this model exhibits drumhead surface states that are exponentially localized at the surface, or weakly localized surface states that decay into the bulk at all energies.Comment: 11 pages, 8 figures, Editors' Suggestio

Зимовий бал Тетяни Клименко

Висвітлено трудовий шлях директора Державного архіву Черкаської області Тетяни Анатоліївни Клименко, яка понад двадцять років працює в архіві.Освещён трудовой путь директора Государственного архива Черкасской области Татьяны Анатольевны Клименко, которая более двадцати лет своей жизни посвятила архивному делу.The article was written on the occasion of fiftieth birthday of the director of The State Archives of Cherkassy region Klymenko Tetyana, whose twenty years seniority is connected with Cherkassy Archives

Морфогенез структуры клеток и сосудов миокарда у экспериментальных животных с моделированным ЮРА

В статье проанализированы морфологические изменения сердечно-сосудистой системы при моделировании ювенильного ревматоидного артрита на 24 белых чистопородных крысах «Wistar». Проведено морфологическое исследование миокарда у животных с экспериментально вызванным ЮРА в зависимости от методов лечения - гормональная терапия и метаболическая коррекция. Дистрофические и деструктивные процессы миокарда в условиях данного эксперимента свидетельствуют о необходимости метаболической коррекции.In the article morphological cardiovascular system analyzed the experimentally caused juvinal rheumatoid arthritis on the 24 white breed «Wistar» rats. It was carried out morphological research of hearts of animals with rheumatoid arthritis depending on the methods of treatments – hormonal therapy and metabolic correction. Dystrophy and disturbance of cardiovascular system of this experiment testifies to necessity of metabolic correction

Extremely high absolute internal quantum efficiency of photoluminescence in co-doped GaN:Zn,Si

We report on the fabrication of GaN co-doped with silicon and zinc by metalorganic vapor phase epitaxy and a detailed study of photoluminescence in this material. We observe an exceptionally high absolute internal quantum efficiency of blue photoluminescence in GaN:Zn,Si. The value of0.93±0.04 has been obtained from several approaches based on rate equations

Landau levels, Bardeen polynomials and Fermi arcs in Weyl semimetals: the who's who of the chiral anomaly

Condensed matter systems realizing Weyl fermions exhibit striking phenomenology derived from their topologically protected surface states as well as chiral anomalies induced by electromagnetic fields. More recently, inhomogeneous strain or magnetization were predicted to result in chiral electric $\mathbf{E}_5$ and magnetic $\mathbf{B}_5$ fields, which modify and enrich the chiral anomaly with additional terms. In this work, we develop a lattice-based approach to describe the chiral anomaly, which involves Landau and pseudo-Landau levels and treats all anomalous terms on equal footing, while naturally incorporating Fermi arcs. We exemplify its potential by physically interpreting the largely overlooked role of Fermi arcs in the covariant (Fermi level) contribution to the anomaly and revisiting the factor of $1/3$ difference between the covariant and consistent (complete band) contributions to the $\mathbf{E}_5\cdot\mathbf{B}_5$ term in the anomaly. Our framework provides a versatile tool for the analysis of anomalies in realistic lattice models as well as a source of simple physical intuition for understanding strained and magnetized inhomogeneous Weyl semimetals.Comment: 10 pages, 7 figure