Heat transfer in a one-dimensional harmonic crystal in a viscous environment subjected to an external heat supply

We consider unsteady heat transfer in a one-dimensional harmonic crystal surrounded by a viscous environment and subjected to an external heat supply. The basic equations for the crystal particles are stated in the form of a system of stochastic differential equations. We perform a continualization procedure and derive an infinite set of linear partial differential equations for covariance variables. An exact analytic solution describing unsteady ballistic heat transfer in the crystal is obtained. It is shown that the stationary spatial profile of the kinetic temperature caused by a point source of heat supply of constant intensity is described by the Macdonald function of zero order. A comparison with the results obtained in the framework of the classical heat equation is presented. We expect that the results obtained in the paper can be verified by experiments with laser excitation of low-dimensional nanostructures.Comment: 12 pages, 5 figure

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

Тонзилектомия − съвременни оперативни техники

Целта на настоящата статия е да се направи сравнително клинично изследване на съвременните оперативни техники и конвенционалната тонзилектомия. За период от две години в УНГ-клиниката на ВМА – София бяха извършени 176 тонзилектомии на болни на възраст от 10 до 45 години. От тях 45% бяха оперирани конвенционално, при 35% бе използван ултразвуков хармоничен скалпел Ultracision, а при останалите 20% бе използван радиочестотен апарат Coblator.Резултатите показаха чувствителна разлика в полза на съвременните оперативни техники (утразвуковата методика и коблатор-техниката).------------------------------------- The purpose of the current article is to make a comparative clinical study of modern operating techniques and cold dissection tonsillectomy. During a period of two years in the ENT department at the Military Medical Academy - Sofia were performed 176 tonsillectomies in patiens between 10 and 45 years of age. 45% of the patients were operated using the conventional methods, 35% were operated using Ultracision and 20% were operated using the radiofrequency Coblation technology.The results showed considerable difference in favor of moden operating techniques (ultrasonic scalpel tonsillectomy or coblation tonsillectomy)

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