Wideband volume horn array antenna with switchable polarization capability

This paper presents the most valuable theoretical results that confirm the possibility of practical realization of a wideband volume horn array antenna with the switchable polarization capability. Among key features of the proposed antennas are their high stability of switchable linear polarization tilt angle of radiated electromagnetic wave, radiation pattern of sector type and wide operating frequency band. The paper focuses on characteristics of linear horn antenna subarrays as key components of the described volume array antenna. Subarrays fully comprise double-ridge waveguide sections. The cutoff wavenumbers calculation algorithm is developed for the symmetrical double-ridge waveguides to estimate frequency bandwidth of power dividers in their different cross sections. The problem is solved numerically by partial regions method taking into account field singularity on rectangular metal ridges

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

Regional aspects of sectoral digitalization : problems and prospects

Purpose: At present, high and sometimes record indicators have been achieved for the individual branches of agricultural production. Further intensive development of agriculture is due to the search for new ways to increase labor productivity and lower production costs which is the main aim of this research. Design/Methodology/Approach: The methodological basis served as a systematic approach, which ensured comprehensiveness and purposefulness. Analytical, abstract-logical, economic-statistical, monographic and experimental research methods were also used in this work to examine problems and prospects of sectoral digitalization. Findings: The agro-industrial complex demonstrates the growth of production indicators and is on the rise. The target indicators, laid down in the Food Security Doctrine, have already been achieved by many indices. To a large extent, it is due to a significant increase in the agro-industrial complex. Practical implications: A proposed platform that would ensure a breakthrough in further technical modernization of production, can be created only if the technologies are improved based on their digitalization and orientation towards a specific consumer. Originality/Value: The pin-point introduction of digital technologies in agricultural production confirms the high efficiency of the full innovative technical modernization. The proposed digital transformation of management in the agro-industrial complex of Russia is the value of this research with its originality compared to other ideas.peer-reviewe

Humans Sensitivity Distribution in Perceptual Space by a Wearable Haptic Sleeve

It is very important to understand humans’ perception when the other communication modalities like vision and audition are partially or fully impaired. Therefore, this paper tries to give a brief overview on humans’ sensitivity distribution in perceptual space. During our experiments, a wearable haptic sleeve consisted of 7 vibro-actuators was used to stimulate subjects arm to convey haptic feedback. The basic research questions in this study are: 1) whether humans’ perception linearly correlated with the actuation frequency, haptic feedback in our scenario 2) humans’ ability to generalise templates via the wearable haptic sleeve. Those findings would be useful to increase humans’ perception when humans have to work with fully or partially impaired perception in their day-to-day life

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

Homocysteine-induced membrane currents, calcium responses and changes in mitochondrial potential in rat cortical neurons

© 2015, Pleiades Publishing, Ltd. Homocysteine, a sulfur-containing amino acid, exerts neurotoxic effects and is involved in the pathogenesis of many neurodegenerative disorders. In contrast to well-studied glutamate excitotoxicity, the mechanism of homocysteine neurotoxicity is not clearly understood. Using wholecell patch-clamp, calcium imaging (fluo-3) and measurements of mitochondrial membrane potential (rhodamine 123), we studied in vitro in cultured rat cortical neurons transmembrane currents, calcium signals and changes in mitochondrial membrane potential induced by homocysteine versus responses induced by NMDA and glutamate. L-homocysteine (50 μM) induced inward currents that were completely blocked by the selective antagonist of NMDA receptors, AP-5. In contrast to NMDA-induced currents, homocysteine-induced currents exhibited a smaller steady-state amplitude. Comparison of calcium responses to homocysteine, NMDA or glutamate demonstrated that in all cortical neurons homocysteine elicited fast oscillatory-type calcium responses, whereas NMDA or glutamate induced a “classical” sustained elevation of intracellular calcium. In contrast to NMDA, homocysteine did not cause a drop in mitochondrial membrane potential at the early stages of its action. However, after its long-term effect, as in cases of NMDA and glutamate, changes in mitochondrial membrane potential arose comparable with its complete drop caused by protonophore FCCP-induced uncoupling of the respiratory chain. Our data suggest that in cultured rat cortical neurons homocysteine at the initial stages of its action induces in vitro neurotoxic effects due to the activation of NMDA-type ionotropic glutamate receptors followed by a massive calcium influx through the channels of these receptors. The long-term effect of homocysteine may lead to mitochondrial dysfuction manifested as a drop in mitochondrial membrane potential

Experimental study of the decay KL0→π0ννˉK_L^0\to\pi^0\nu\bar{\nu}

The first dedicated search for the rare neutral-kaon decay $K_L^0\to\pi^0\nu\bar{\nu}$ has been carried out in the E391a experiment at the KEK 12-GeV proton synchrotron. The final upper limit of 2.6 $\times 10^{-8}$ at the 90% confidence level was set on the branching ratio for the decay.Comment: 23 pages, 27 figures, accepted for publication as a regular article in Physical Review

Improving the lake scheme within a coupled WRF‐lake model in the Laurentian Great Lakes

In this study, a one‐dimensional (1‐D) thermal diffusion lake model within the Weather Research and Forecasting (WRF) model was investigated for the Laurentian Great Lakes. In the default 10‐layer lake model, the albedos of water and ice are specified with constant values, 0.08 and 0.6, respectively, ignoring shortwave partitioning and zenith angle, ice melting, and snow effect. Some modifications, including a dynamic lake surface albedo, tuned vertical diffusivities, and a sophisticated treatment of snow cover over lake ice, have been added to the lake model. A set of comparison experiments have been carried out to evaluate the performances of different lake schemes in the coupled WRF‐lake modeling system. Results show that the 1‐D lake model is able to capture the seasonal variability of lake surface temperature (LST) and lake ice coverage (LIC). However, it produces an early warming and quick cooling of LST in deep lakes, and excessive and early persistent LIC in all lakes. Increasing vertical diffusivity can reduce the bias in the 1‐D lake but only in a limited way. After incorporating a sophisticated treatment of lake surface albedo, the new lake model produces a more reasonable LST and LIC than the default lake model, indicating that the processes of ice melting and snow accumulation are important to simulate lake ice in the Great Lakes. Even though substantial efforts have been devoted to improving the 1‐D lake model, it still remains considerably challenging to adequately capture the full dynamics and thermodynamics in deep lakes.Key PointsA dynamic lake surface albedo scheme is added to the lake modelThe new lake model produces a more reasonable LST and LIC than the default lake modelIce melting and snow accumulation are important to simulating lake ice in the Great LakesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135995/1/jame20346_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135995/2/jame20346.pd