204 research outputs found

    Influence of contacts on the microwave response of a two-dimensional electron stripe

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    Electromagnetic response of a finite-width two-dimensional electron stripe with attached metallic side contacts is theoretically studied. It is shown that contacts substantially influence the position, the linewidth, and the amplitude of plasmon-polariton resonances in the stripe. In finite magnetic fields, absorption of the wave with the inactive circular polarization (which is not absorbed in an infinite system without contacts) may become larger than that of the wave with the active polarization. The results are discussed in view of recent microwave experiments in two-dimensional electron systems.Comment: 13 pages, incl. 9 figures, the paper has been substantially modified and extended, new results have been added. Accepted for publication in Phys. Rev.

    Contribution to the knowledge of the fauna of noctuoid moths (Lepidoptera: Noctuoidea) of Kyrgyzstan

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    The paper contains data about 354 species of owlet moths, collected in 2017–2020 in Kyrgyzstan. This work is based on the examination of 4043 specimens, from which genitalia for 600 specimens were dissected. The following number of species is recorded for various territories of the country for the first time: 12 species for Kyrgyzstan; 27 species for West TianShan; eight species for Central Tian-Shan; 29 species for Inner Tian-Shan; one species for North Tian-Shan; 10 species for Alai. In total, 878 species of moths are known in the fauna of Kyrgyzstan. Due to the intermediate position of Kyrgyzstan between Kazakhstan and Tajikistan we can predict an average species number in Kyrgyzstan as between 950 and 1000 species. Thus, the fauna of Noctuoidea of this country is studied by 80–90% to the present time

    New data on the fauna of the owlets (Lepidoptera: Noctuidae s. l.) of Kabardino-Balkaria

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    Based on the unpublished data from the collection of Zoological Institute RAS and collections of A.A. Bolov in 2005, the preceding species list (Nolidae, Erebidae, Noctuidae) of Kabardino-Balkaria (Poltavsky, Nekrasov, 2002) is here complemented by 30 more species. Now 226 species are known for the fauna of the region, what is approximately 50-60% of the estimated fauna there. One species,Tarachidia candefacta, was found in Central Caucasus for the first tim

    THE PARTNERSHIP BETWEEN FAMILY AND PRESCHOOL INSTITUTIONS AS SUPPORT OF PARENTHOOD

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    Složenost uvjeta u društvenom, političkom i gospodarskom području stvaraju nepovoljno ozračje u kojem se suvremena obitelj susreće s brojnim izazovima, a posebice roditelji u obnašanju svojih roditeljskih zadaća. Roditelji trebaju adekvatnu društvenu potporu i formalnih i neformalnih izvora društvene potpore. Kako bi se realizirao holistički pristup društvenoj potpori roditeljima, potrebno je uspostaviti partnerske odnose između roditelja i relevantnih čimbenika društvenog konteksta, odnosno integrirati sve sustave (zdravstvo, predškolski odgoj i obrazovanje, socijalnu skrb i civilni sektor) u funkciji potpore roditeljstvu. Tu posebnu zadaću imaju predškolske ustanove od kojih se očekuje prepoznavanje potreba djece i roditelja, kao i motiviranje i uključivanje roditelja u partnerske odnose s djelatnicima predškolskih ustanova.The complexity of the conditions in the social, political and economic area creates an unfavourable environment in which the modern family faces many challenges, especially parents in their parenting. Parents need adequate social support, both from formal and informal sources of social support. In order to implement a holistic approach to parents’ social support, it is necessary to establish partnership relations between the parents and the relevant factors of the social context, and integrate all systems (health care, preschool education, social welfare and civil sector) as a support for parenting. The preschool institutions have a special mission – to recognize the needs of children and parents, as well as to motivate and involve parents in partnership with the preschool institutions staff

    Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases

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    We report on the observation of collective radiative decay, or superradiance, of cyclotron resonance (CR) in high-mobility two-dimensional electron gases in GaAs quantum wells using time-domain terahertz magnetospectroscopy. The decay rate of coherent CR oscillations increases linearly with the electron density in a wide range, which is a hallmark of superradiant damping. Our fully quantum mechanical theory provides a universal formula for the decay rate, which reproduces our experimental data without any adjustable parameter. These results firmly establish the many-body nature of CR decoherence in this system, despite the fact that the CR frequency is immune to electron-electron interactions due to Kohn's theorem.Comment: 5 pages, 4 figure

    A survey of Erebidae, Nolidae and Euteliidae (Lepidoptera) in Southern and Northeastern of Iran.

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    Noctuoidea are the largest superfamily of Lepidoptera which have not yet fully investigated in Iran. In order to inventories such important group, faunistic studies on the families Erebidae, Nolidae and Euteliidae were made by light traps mainly in the three Iranian provinces of Fars, Khuzestan and Khorasan-e-Razavi during 2009-2011. Totally, 42 taxa belonging to 26 genera and 7 subfamilies were collected. Among these, one species – Drasteria kusnezovi (John, 1910) – is newly reported for the Iranian fauna, together with 23 new provincial records. For all species, illustrations of adults and their genitalia are given with remarks

    Materials on the Lepidoptera fauna of the Dagestan Republic (Northeastern Caucasus, Russia): autumn aspect (Insecta: Lepidoptera)

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    The article provides the list of Lepidoptera (the families: Cossidae, Coleophoridae, Choreutidae, Ethmiidae, Pterophoridae, Pyralidae, Crambidae, Lemoniidae, Lasiocampidae, Drepanidae, Geometridae, Sphingidae, Erebidae, Noctuidae, Lycaenidae, Nymphalidae, Pieridae), collected in four localities in the Republic of Dagestan in September 2020. In total, 207 species have been recorded. Five species are reported for the fauna of Russia for the first time: Casignetella texanella (Chambers, 1878) (Coleophoridae), Agriphila cyrenaicellus (Ragonot, 1887), Thyridiphora furia (Swinhoe, 1884), Haritalodes derogata (Fabricius, 1775) (Crambidae), and Scopula minorata (Boisduval, 1833) (Geometridae); 23 species - for the fauna of Eastern Caucasus: Perygra glaucicolella (Wood, 1892), Ecebalia halophilella (Zimmermann, 1926), E. linosyris (E. Hering, 1937), Ionescumia clypeiferella (O. Hofmann, 1871), Carpochena trientella (Christpoh, 1872) (Coleophoridae), Tebenna micalis (Mann, 1857) (Choreutidae), Ethmia candidella (Alpheraky, 1908) (Ethmiidae), Stenoptilia zophodactyla (Duponchel, 1838), Stenoptilodes taprobanes (Felder & Rogenhofer, 1875), Crombrugghia laetus (Zeller, 1847) (Pterophoridae), Glyptoteles leucacrinella Zeller, 1848, Cadra calidella (Guenée, 1845), (Pyralidae), Agriphila selasella (Hübner, 1813), Agriphila tolli (Bleszynski, 1952), Agriphila poliellus (Treitschke, 1832), Pediasia contaminella (Hübner, 1796), Pediasia fascelinella (Hübner, [1813]), Uresiphita gilvata (Fabricius, 1794), Antigastra catalaunalis (Duponchel, 1833) (Crambidae), Watsonalla binaria (Hufnagel, 1767) (Drepanidae), Idaea degeneraria erschoffi (Christoph, 1872), Scopula nigropunctata (Hufnagel, 1767), and Rhodometra sacraria (Linnaeus, 1767) (Geometridae)
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