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

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.

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

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)

Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases

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

Tracking Growing Axons by Particle Filtering in 3D+t Fluorescent Two-Photon Microscopy Images

International audienceAnalyzing the behavior of axons in the developing nervous systems is essential for biologists to understand the biological mechanisms underlying how growing axons reach their target cells. The analysis of the motion patterns of growing axons requires detecting axonal tips and tracking their trajectories within complex and large data sets. When performed manually, the tracking task is arduous and time-consuming. To this end, we propose a tracking method, based on the particle filtering technique, to follow the traces of axonal tips that appear as small bright spots in the 3D+t fluorescent two-photon microscopy images exhibiting low signal-to-noise ratios (SNR) and complex background. The proposed tracking method uses multiple dynamic models in the proposal distribution to predict the positions of the growing axons. Furthermore, it incorporates object appearance, motion characteristics of the growing axons, and filament information in the computation of the observation model. The integration of these three sources prevents the tracker from being distracted by other objects that have appearances similar to the tracked objects, resulting in improved accuracy of recovered trajectories. The experimental results obtained from the microscopy images show that the proposed method can successfully estimate trajectories of growing axons, demonstrating its effectiveness even under the presence of noise and complex background

Distinct ECM mechanosensing pathways regulate microtubule dynamics to control endothelial cell branching morphogenesis

The compliance and dimensionality of the ECM regulate distinct changes in microtubule growth speed and growth persistence

A proteomic approach reveals integrin activation state-dependent control of microtubule cortical targeting

Integrin activation, which is regulated by allosteric changes in receptor conformation, enables cellular responses to the chemical, mechanical and topological features of the extracellular microenvironment. A global view of how activation state converts the molecular composition of the region proximal to integrins into functional readouts is, however, lacking. Here, using conformation-specific monoclonal antibodies, we report the isolation of integrin activation state-dependent complexes and their characterization by mass spectrometry. Quantitative comparisons, integrating network, clustering, pathway and image analyses, define multiple functional protein modules enriched in a conformation-specific manner. Notably, active integrin complexes are specifically enriched for proteins associated with microtubule-based functions. Visualization of microtubules on micropatterned surfaces and live cell imaging demonstrate that active integrins establish an environment that stabilizes microtubules at the cell periphery. These data provide a resource for the interrogation of the global molecular connections that link integrin activation to adhesion signalling

Аналітичні моделі багатопріоритетних хмарних дата-ценрів зі змішаною дисципліною надання послуг з урахуванням особливостей функціонування та можливих відмов

One of the main indicators of the effectiveness of cloud data centers are indicators based on the assessment of temporal characteristics. Violation of permissible time constraints, for example, the response time of cloud data centers, has a negative impact on the efficiency of solving user target tasks. This is of particular importance for real-time systems and, above all, for special information systems built using private clouds. Analytical models of cloud data centers are developed as queuing systems with a mixed discipline of resource allocation. The models take into account failures and various features of functioning and have arbitrary distribution laws for some stochastic processes. For each model, analytical expressions for computing time characteristics have been obtained. Such models for the cloud data centers are used for the first time. General description of the models is as follows. At the input of the cloud date - center, which implements a mixed service discipline (with relative and absolute priorities), receives N Poisson flows of requests for resources with corresponding N priorities. Duration of service for applications of various flows have their own arbitrary distribution laws. An application with relative priority, whose service is interrupted by applications with absolute priority, returns to the queue. Two disciplines for the renewal of service A and B are considered. Within the same priority, applications are serviced in the order of receipt.Cloud the date-center refuses to provide resources (for example, fails) under the Poisson law, and is restored under an arbitrary law. During the recovery period, elements of adaptation to failures are used: applications of some flows to the queue are accepted and accumulated, while others are not accepted (the discipline of the queue replenishment, I and II, respectively). The denial of service device can occur both during its free state and during the application processing. Two disciplines of resumption of service after restoration C and D have been considered. An interrupted application is processed from the point of its interruption. The combination of disciplines — resumption of service and queue replenishment — allows us to consider independent models of various types of systems that have the respective designation.Different features of functioning consist of various combinations of disciplines A, B, C, D, I and II, for which analytical formulas for calculating time characteristics of different types of systems have been obtained.Одними із основних показників ефективності хмарних дата-центрів є показники, що базуються на оцінці часових характеристик. Порушення припустимих часових обмежень, наприклад, часу відгуку хмарних дата-центрів, негативно позначається на ефективності рішення цільових задач користувачів. Це має особливе значення для систем реального масштабу часу і, в першу чергу, для спеціальних інформаційних систем, що побудовані з використанням приватних хмар. Розроблено аналітичні моделі хмарних дата-центрів як системи масового обслуговування зі змішаною дисципліною надання ресурсів. Моделі врахо-вують відмови й різні особливості функціонування та мають довільні закони розподілення для деяких вірогідних процесів. Для кожної моделі отримано аналітичні вирази часових характеристик. Такі моделі для хмарних дата-центрів використано вперше

Records of some rare noctuid moths (Lepidoptera: Noctuidae) in Daghestan republic (Russia) in 2009

Volume: 40Start Page: 56End Page: 6