Fluctuation-induced traffic congestion in heterogeneous networks

In studies of complex heterogeneous networks, particularly of the Internet, significant attention was paid to analyzing network failures caused by hardware faults or overload, where the network reaction was modeled as rerouting of traffic away from failed or congested elements. Here we model another type of the network reaction to congestion -- a sharp reduction of the input traffic rate through congested routes which occurs on much shorter time scales. We consider the onset of congestion in the Internet where local mismatch between demand and capacity results in traffic losses and show that it can be described as a phase transition characterized by strong non-Gaussian loss fluctuations at a mesoscopic time scale. The fluctuations, caused by noise in input traffic, are exacerbated by the heterogeneous nature of the network manifested in a scale-free load distribution. They result in the network strongly overreacting to the first signs of congestion by significantly reducing input traffic along the communication paths where congestion is utterly negligible.Comment: 4 pages, 3 figure

Temporal Correlations of Local Network Losses

We introduce a continuum model describing data losses in a single node of a packet-switched network (like the Internet) which preserves the discrete nature of the data loss process. {\em By construction}, the model has critical behavior with a sharp transition from exponentially small to finite losses with increasing data arrival rate. We show that such a model exhibits strong fluctuations in the loss rate at the critical point and non-Markovian power-law correlations in time, in spite of the Markovian character of the data arrival process. The continuum model allows for rather general incoming data packet distributions and can be naturally generalized to consider the buffer server idleness statistics

Один із методів скидання авіаційного підвісного блока із змінною геометрією

One method to drop the aviation outboard block with variable geometry is proposed. Forgrounding of this method the calculation and exploration of aerodynamic characteristics of the outboardblock, which consists of the outward cylindrical body and inside a sharp body of rotation with a tail plumage,is performed. Estimation of the implementation possibility of a method to drop such block is carriedout alsoВыполнены расчет и исследования аэродинамических характеристик подвесного блока, который состоит из внешнего цилиндрического корпуса и внутреннего острого тела вращения с хвостовым оперением для обоснования этого метода. Проведена оценка возможности реализации данного метода сбросаВиконані розрахунок і дослідження аеродинамічних характеристик підвісного блока, який складається із зовнішнього циліндричного корпуса і внутрішнього гострого тіла обертання з хвостовим оперенням для обґрунтування цього методу. Проведено оцінювання можливості реалізації даного методу скиданн

Random Walks in Local Dynamics of Network Losses

We suggest a model for data losses in a single node of a packet-switched network (like the Internet) which reduces to one-dimensional discrete random walks with unusual boundary conditions. The model shows critical behavior with an abrupt transition from exponentially small to finite losses as the data arrival rate increases. The critical point is characterized by strong fluctuations of the loss rate. Although we consider the packet arrival being a Markovian process, the loss rate exhibits non-Markovian power-law correlations in time at the critical point.Comment: 4 pages, 2 figure

Quantum-dot spin qubit and hyperfine interaction

We review our investigation of the spin dynamics for two electrons confined to a double quantum dot under the influence of the hyperfine interaction between the electron spins and the surrounding nuclei. Further we propose a scheme to narrow the distribution of difference in polarization between the two dots in order to suppress hyperfine induced decoherence.Comment: 12 pages, 3 figures; Presented as plenary talk at the annual DPG meeting 2006, Dresden (to appear in Advances in Solid State Physics vol. 46, 2006

Dispersively detected Pauli Spin-Blockade in a Silicon Nanowire Field-Effect Transistor

We report the dispersive readout of the spin state of a double quantum dot formed at the corner states of a silicon nanowire field-effect transistor. Two face-to-face top-gate electrodes allow us to independently tune the charge occupation of the quantum dot system down to the few-electron limit. We measure the charge stability of the double quantum dot in DC transport as well as dispersively via in-situ gate-based radio frequency reflectometry, where one top-gate electrode is connected to a resonator. The latter removes the need for external charge sensors in quantum computing architectures and provides a compact way to readout the dispersive shift caused by changes in the quantum capacitance during interdot charge transitions. Here, we observe Pauli spin-blockade in the high-frequency response of the circuit at finite magnetic fields between singlet and triplet states. The blockade is lifted at higher magnetic fields when intra-dot triplet states become the ground state configuration. A lineshape analysis of the dispersive phase shift reveals furthermore an intradot valley-orbit splitting $\Delta_{vo}$ of 145 $\mu$eV. Our results open up the possibility to operate compact CMOS technology as a singlet-triplet qubit and make split-gate silicon nanowire architectures an ideal candidate for the study of spin dynamics

Driven coherent oscillations of a single electron spin in a quantum dot

The ability to control the quantum state of a single electron spin in a quantum dot is at the heart of recent developments towards a scalable spin-based quantum computer. In combination with the recently demonstrated exchange gate between two neighbouring spins, driven coherent single spin rotations would permit universal quantum operations. Here, we report the experimental realization of single electron spin rotations in a double quantum dot. First, we apply a continuous-wave oscillating magnetic field, generated on-chip, and observe electron spin resonance in spin-dependent transport measurements through the two dots. Next, we coherently control the quantum state of the electron spin by applying short bursts of the oscillating magnetic field and observe about eight oscillations of the spin state (so-called Rabi oscillations) during a microsecond burst. These results demonstrate the feasibility of operating single-electron spins in a quantum dot as quantum bits.Comment: Total 25 pages. 11 pages main text, 5 figures, 9 pages supplementary materia

UCRAID (Ukrainian Citizen and refugee electronic support in Respiratory diseases, Allergy, Immunology and Dermatology) action plan

Eight million Ukrainians have taken refuge in the European Union. Many have asthma and/or allergic rhinitis and/or urticaria, and around 100,000 may have a severe disease. Cultural and language barriers are a major obstacle to appropriate management. Two widely available mHealth apps, MASK-air® (Mobile Airways Sentinel NetworK) for the management of rhinitis and asthma and CRUSE® (Chronic Urticaria Self Evaluation) for patients with chronic spontaneous urticaria, were updated to include Ukrainian versions that make the documented information available to treating physicians in their own language. The Ukrainian patients fill in the questionnaires and daily symptom-medication scores for asthma, rhinitis (MASK-air) or urticaria (CRUSE) in Ukrainian. Then, following the GDPR, patients grant their physician access to the app by scanning a QR code displayed on the physician's computer enabling the physician to read the app contents in his/her own language. This service is available freely. It takes less than a minute to show patient data to the physician in the physician's web browser. UCRAID—developed by ARIA (Allergic Rhinitis and its Impact on Asthma) and UCARE (Urticaria Centers of Reference and Excellence)—is under the auspices of the Ukraine Ministry of Health as well as European (European Academy of Allergy and Clinical immunology, EAACI, European Respiratory Society, ERS, European Society of Dermatologic Research, ESDR) and national societies

Conjugation of Organoruthenium(II) 3-(1H-Benzimidazol-2-yl)pyrazolo[3,4-b]pyridines and Indolo[3,2-d]benzazepines to Recombinant Human Serum Albumin: a Strategy To Enhance Cytotoxicity in Cancer Cells

Five organoruthenium complexes [RuCl(η6-arene)(L)]Cl with a modified arene ligand, namely, 4-formylphenoxyacetyl-η6-benzylamide, and L = 3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines or indolo[3,2-d]benzazepines were synthesized and conjugated to recombinant human serum albumin in order to improve their drug targeting and delivery to cancer cells, and a marked increase in cytotoxicity was observed

Search for the decay KL0→3γK_L^0 \rightarrow 3\gamma

We performed a search for the decay $K_L^0 \rightarrow 3\gamma$ with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of $K_L^0 \rightarrow 3\gamma$ proceeding via parity-violation, we obtained the single event sensitivity to be $(3.23\pm0.14)\times10^{-8}$, and set an upper limit on the branching ratio to be $7.4\times10^{-8}$ at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of $K_L^0 \rightarrow 3\gamma$ proceeding via parity-conservation were also presented in this paper