1,205 research outputs found
Institutional and organizational features of cross-border cargo traffic in the post-soviet space integration terms. Part I
The article covers the technical, technological, institutional, and organizational barriers of cross-border transportation of cargo. The study uses an institutional approach as a methodological alternative to other approaches. The study touches on institutional and organizational problems of border crossing checkpoints arrangement, the consequences of the application of unified transport documents and the introduction of electronic communication forms. Particular attention is paid to the analysis of demonstrative actions and the daily practice of reducing the time of customs procedures and reducing transaction costs of cross-border cargo traffic. Herewith it is indicated that the most effective way to improve the efficiency of cross-border transportation of cargo suggests simultaneous implementation of technical and institutional innovations. Emphasis is placed on identifying the institutional and organizational features of the international road transportation of cargo, in particular, the problems of the evolution of the guaranteed customs duties payment institute, the permission system in the implementation of cross-border cargo traffic. The fact that the state support of national entrepreneurs requires a mechanism to ensure the parity of Russian and foreign carriers, at least in the field of cargo transportation for state needs, with the involvement of credit resources of government-linked banks is highlighted. It is underlined that the first step towards improving the institutional environment of international road transportation should envisage the elimination of all informal (shadow) relations in this sphere. The article identifies institutional features of cargo transportation in specific areas such as deliveries by road to China through Kazakhstan, and the challenges and prospects for the use and development of transit potential of Kaliningrad Region. The article shows institutional and organizational characteristics of combined transportation in cross-border traffic. The article concludes that the development of cross-border transportation of cargo and the implementation of transport and transit potential of EAEU member states may and should become a powerful source of income for business entities, budgets of all levels and households, as well as the driving force of industrial and technological upgrading and institutional and organizational evolution of economic systems of the countries and integration associations.The article has been prepared with the support of the Russian Foundation for Basic Research (Project № 15-06-06939 a «Modelling the cyclical evolution of mutual influence of the national transport system and the state of the markets of goods (services), labor and capital in terms of integration and global instability»)
Serotonin Modulates Oscillations of the Membrane Potential in Isolated Spinal Neurons from Lampreys
Studies were performed on spinal neurons from lampreys isolated by an enzymatic/mechanical method using pronase. The effects of 100 µM serotonin (5-HT) on membrane potential oscillations induced by a variety of excitatory amino acids were studied. 5-HT was found to depolarize branched cells (presumptive motoneurons and interneurons) by 2–6 mV without inducing membrane potential oscillations. However, when oscillations were already present because of an excitatory amino acid, 5-HT changed the parameters of these oscillations, increasing the amplitudes of all types of oscillations, increasing the frequency of irregular oscillations, and increasing the duration of the depolarization plateaus accompanied by action potentials. Serotonin modulation of the effects of excitatory amino acids and the electrical activity of cells in the neural locomotor network facilitates motor activity and leads to increases in the contraction of truncal muscles and more intense movements by the animal. The possible mechanisms of receptor coactivation are discussed, along with increases in action potential frequency and changes in the parameters of the locomotor rhythm
The Effects of Serotonin on Functionally Diverse Isolated Lamprey Spinal Cord Neurons
The experiments reported here showed that application of serotonin (5-hydroxytryptamine, 5-HT) (100 µ M) did not induce any significant current through the membranes of any of the spinal neurons studied (n = 62). At the same time, the membranes of most motoneurons and interneurons (15 of 18) underwent slight depolarization (2–6 mV) in the presence of 5-HT, which was not accompanied by any change in the input resistance of the cells. Depolarization to 10–20 mV occurred in some cells (3 of 18) of these functional groups, this being accompanied by 20–60% decreases in input resistance. The same concentration of 5-HT induced transient low-amplitude depolarization of most sensory spinal neurons (dorsal sensory cells), this changing smoothly to long-term hyperpolarization by 2–7 mV. The input resistance of the cell membranes in these cases showed no significant change (n = 8). Data were obtained which provided a better understanding of the mechanism by which 5-HT modulates the activity of spinal neurons. Thus, 5-HT facilitates chemoreceptive currents induced by application of NMDA to motoneurons and interneurons, while the NMDA responses of dorsal sensory cells were decreased by 5-HT. 5-HT affected the post-spike afterresponses of neurons. 5-HT significantly decreased the amplitude of afterhyperpolarization arising at the end of the descending phase of action potentials in motoneurons and interneurons and increased the amplitude of afterdepolarization in these types of cells. In sensory spinal neurons, 5-HT had no great effect on post-spike afterresponses. The results obtained here support the suggestion that 5-HT significantly modulates the activity of spinal neurons of different functional types. 5-HT facilitates excitation induced by subthreshold depolarization in motoneurons and some interneurons, facilitating the generation of rhythmic discharges by decreasing afterhyperpolarization. In sensory cells, 5-HT enhances inhibition due to hyperpolarization, suppressing NMDA currents. The differences in the effects of 5-HT on functionally diverse neurons are presumed to be associated with the combination of different types of 5-HT receptors on the membranes of these types of spinal neurons
Phytoplankton of the delta of the Mekong River during the dry season
Human activity has disturbed the functioning of river ecosystems all around the globe. The current global climatic fluctuations and local anthropogenic impact lead to rearrangement in the structure and functioning of aquatic communities. One of the most important components of aquatic ecosystems is phytoplankton as the main primary producer of the organic matter, the basis for trophic relations and indicator of changes in the environment. This article presents the first results of a study concerning the peculiarities of quantitative distribution of biomass and species composition of phytoplankton in the delta of the Mekong River at the beginning of the dry season (December of 2018). Diatoms dominated according to biomass practically in all the stations of selection of samples. The total biomass of phytoplankton on average accounted for 0.049 ± 0.007 mg/L at the abundance of 40 ± 7 103 ind./L. In practically all the studied plots, according to biomass, the dominating diatoms were first of all Aulacoseira granulata, A. islandica, Cyclotella meneghiniana, Cyclotella spp., and Oxyneis binalis. Among Chlorophyta, most often we found Chlorella sp. and Scenedesmus quadricauda, but their biomass was insignificant. We determined statistically significant correlation relationships between biomass of phytoplankton and hydrological parameters. Based on the Spearman’s rank correlation coefficient, we determined negative relations between the total biomass of phytoplankton with salinity and pH. Positive correlation was seen between the biomass of diatoms and turbidity, and also between the temperature and the biomass of chlorophytes and Dinophyta. The biomass of golden algae (Chrysophyceae) and Dinophyta positively correlated with the mineralization. Quantitative regression analysis confirmed the close relationship between the total biomass of phytoplankton, hydrophysical and hydrochemical parameters. Besides the importance of scientific data on biological diversity and ecology of plankton algae, the results we obtained are necessary for organizing biological monitoring in the delta of the Mekong River in the future
Investigation of GdBaCo2-xFexO6-δ (x = 0, 0.2) - Ce0.8Sm0.2O2 composite cathodes for intermediate temperature solid oxide fuel cells
The double perovskites GdBaCo2-xFexO 6-δ (x = 0, 0.2) and composites (100 - y) GdBaCo 2-xFexO6-δ (x = 0, 0.2) - y Ce 0.8Sm0.2O2 (y = 10-50 wt.%) were investigated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). Chemical compatibility of GdBaCo2-xFexO 6-δ (x = 0, 0.2) with solid electrolyte Ce0.8Sm 0.2O2, thermal expansion, DC conductivity and electrochemical performance of (100 - y) GdBaCo2-xFe xO6-δ (x = 0, 0.2) - y Ce0.8Sm 0.2O2 (y = 10-50 wt.%) were studied. Partial substitution of Fe for Co was shown to lead to decrease of double perovskite GdBaCo 2-xFexO6-δ reactivity with the solid electrolyte Ce0.8Sm0.2O2. Polarization resistance of cathodes studied was found to depend significantly on firing temperature. Variation of solid electrolyte content in (100 - y) GdBaCo 2-xFexO6-δ (x = 0, 0.2) - y Ce 0.8Sm0.2O2 (y = 10-50 wt.%) composites was shown to allow to optimize their electrochemical performance. Cathode materials of 80 wt.% GdBaCo2O6-δ - 20 wt.% Ce 0.8Sm0.2O2 and 65 wt.% GdBaCo 1.8Fe0.2O6-δ - 35 wt.% Ce 0.8Sm0.2O2 were found to have the lowest polarization resistances and reasonable values of thermal expansion coefficient (TEC) and, therefore, can be considered as promising cathode materials for IT-SOFCs. © 2013 Elsevier B.V. All rights reserved
Calculation of overdamped c-axis charge dynamics and the coupling to polar phonons in cuprate superconductors
In our recent paper we presented empirical evidences suggesting that
electrons in cuprate superconductors are strongly coupled to unscreened c-axis
polar phonons. In the overdoped regime the c-axis metallizes and we present
here simple theoretical arguments demonstrating that the observed effect of the
metallic c-axis screening on the polar electron-phonon coupling is consistent
with a strongly overdamped c-axis charge dynamics in the optimally doped
system, becoming less dissipative in the overdoped regime.Comment: 6 pages, 1 figure. to be published in Phys. Rev.
Nonlinear emission dynamics of a GaAs microcavity with embedded quantum wells
The emission dynamics of a GaAs microcavity at different angles of
observation with respect to the sample normal under conditions of nonresonant
picosecond-pulse excitation is measured. At sufficiently high excitation
densities, the decay time of the lower-polariton emission increases with the
polariton wavevector; at low excitation densities the decay time is independent
of the wavevector. The effect of additional nonresonant continuous illumination
on the emission originating from the bottom of the lower polariton branch is
investigated. The additional illumination leads to a substantial increase in
the emission intensity (considerably larger than the intensity of the
photoluminescence excited by this illumination alone). This fact is explained
in terms of acceleration of the polariton relaxation to the radiative states
due to scattering by charge carriers created by the additional illumination.
The results obtained show, that at large negative detunings between the photon
and exciton modes, polariton-polariton and polariton-free carrier scattering
are the main processes responsible for the filling of states near the bottom of
the lower polariton branch.Comment: 10 pages, 6 figures. This is an author-created, un-copyedited version
of an article accepted for publication in Journal of Physics: Condesed
Matter. IOP Publishing Ltd is not responsible for any errors or omissions in
this version of the manuscript or any version derived from i
C-axis Penetration Depth and Inter-layer Conductivity in the Thallium Based Cuprate Superconductors
The c-axis Josephson plasmon in optimally doped single-layer and bi-layer
high Tc cuprates Tl2201 and Tl2212 have been investigated using infrared
spectroscopy. We observed the plasma frequencies for these two compounds at
27.8 and 25.6 cm-1 respectively, which we interpret as a Josephson resonance
across the TlO blocking layers. No maximum in the temperature dependence of the
c-axis conductivity was observed below Tc, indicating that even in the
superconducting state a coherent quasi-particle contribution to the c-axis
conductivity is absent or very weak, in contrast to the behaviour of the
ab-plane conductivity.Comment: 4 pages, 3 figure
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