2,162 research outputs found

    Russian fiscal policy during the financial crisis

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    This study examines the expanding role of fiscal policy at a time of financial crisis. It analyses the stimulative fiscal measures of the Russian government in 2008-2010 and compares these with simi-lar actions taken in other countries. The risks and limitations associated with the development and implementation of the measures are analyzed. The macroeconomic effects of the fiscal policy measures are estimated using a structural vector autoregressive (SVAR) model, the fiscal multip-liers are calculated, and factors influencing multiplier size are examined.fiscal stimulus; fiscal sustainability; SVAR; fiscal multiplier; financial crisis; Russia

    Development of an Autoclave Thermal Processes Model for the Simulator of Canned Food Sterilization Process

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    The article describes an autoclave thermal processes model, which is used for the simulator of canned food sterilization process. The simulator is based on a simulation model that adequately describes the reaction of the autoclave to the actions of the control system and the operator of the sterilization unit. The model’s parameters were obtained by means of experimental data processing. The computer program ”autoclave Model” for simulating sterilization process in the steam and water environment is described. The examples of the canned food’s manual control sterilization modeling are shown. The results of numerical mathematical modeling of canned food sterilization processes in the autoclave showed a high degree of the implemented process models quality of approximation. The calculation schemes done as a result of the mathematical models creation were used to develop a hardwaresoftware complex of the sterilization process simulator. The increase of training level on carrying out process of canned goods sterilization will be provided as a result of designing the simulator of sterilization process in educational process. Consequently reducing defects in production and improving the quality of canned products are expected

    Changes of Granite Rapakivi under the Biofouling Influence

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    Interdisciplinary study of granite rapakivi biofouling in the natural and anthropogenic environment (St. Petersburg, Vyborg, Southern Finland) was carried out. The biodiversity of microorganisms (cyanobacteria, micromycetes, and organotrophic bacteria) and various types of biofilms are characterized. The influence of external factors on the changes of cyanobacterial biofilms is shown. The features of biofilms localization on the granite surface in an urban environment and in natural outcrops are studied. Differences in the biofilms metabolites composition at the granite quarries and monuments of St. Petersburg are shown. The behavior of chemical elements during the bioweathering of granite is estimated. The role of biofilms in the accumulation of chemical elements on the surface of granite is established. The dynamics of chemical elements leaching from granite may depend on the type of biofilm developing on granite

    Four-Band Hamiltonian for fast calculations in intermediate-band solar cells

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    The 8-dimensional Luttinger–Kohn–Pikus–Bir Hamiltonian matrix may be made up of four 4-dimensional blocks. A 4-band Hamiltonian is presented, obtained from making the non-diagonal blocks zero. The parameters of the new Hamiltonian are adjusted to fit the calculated effective masses and strained QD bandgap with the measured ones. The 4-dimensional Hamiltonian thus obtained agrees well with measured quantum efficiency of a quantum dot intermediate band solar cell and the full absorption spectrum can be calculated in about two hours using Mathematica© and a notebook. This is a hundred times faster than with the commonly-used 8-band Hamiltonian and is considered suitable for helping design engineers in the development of nanostructured solar cells

    Aluminum surface layer strengthening using intense pulsedbeam radiation of substrate film system

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    The paper presents formation of the substrate film system (Zr-Ti-Cu/Al) by electric arc spraying of cathode having the appropriate composition. It is shown that the intense beam radiation of the substrate film system is accompanied by formation of the multi-phase state, the microhardness of which exceeds the one of pure A7 aluminum by = 4.5 times

    Resonant phonon-magnon interactions in free-standing metal-ferromagnet multilayer structures

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    We analyze resonant magneto-elastic interactions between standing perpendicular spin wave modes (exchange magnons) and longitudinal acoustic phonon modes in free-standing hybrid metal-ferromagnet bilayer and trilayer structures. Whereas the ferromagnetic layer acts as a magnetic cavity, all metal layers control the frequencies and eigenmodes of acoustic vibrations. The here proposed design allows for achieving and tuning the spectral and spatial modes overlap between phonons and magnons that results in their strong resonant interaction. Realistic simulations for gold-nickel multilayers show that sweeping the external magnetic field should allow for observing resonantly enhanced interactions between individual magnon and phonon modes in a broad range of frequencies spanning from tens of GHz up to several hundreds of GHz, which can be finely tuned through the multilayer design. Our results would enable the systematic study and the deep understanding of resonantly enhanced magneto-elastic coupling between individual phonon and magnon modes up to frequencies of great contemporary fundamental and applied interest.Comment: 9 pages, 6 figure

    Spiking neural network with local plasticity and sparse connectivity for audio classification

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    Purpose. Studying the possibility of implementing a data classification method based on a spiking neural network, which has a low number of connections and is trained based on local plasticity rules, such as Spike-Timing-Dependent Plasticity. Methods. As the basic architecture of a spiking neural network we use a network included an input layer and layers of excitatory and inhibitory spiking neurons (Leaky Integrate and Fire). Various options for organizing connections in the selected neural network are explored. We have proposed a method for organizing connectivity between layers of neurons, in which synaptic connections are formed with a certain probability, calculated on the basis of the spatial arrangement of neurons in the layers. In this case, a limited area of connectivity leads to a higher sparseness of connections in the overall network. We use frequency-based coding of data into spike trains, and logistic regression is used for decoding. Results. As a result, based on the proposed method of organizing connections, a set of spiking neural network architectures with different connectivity coefficients for different layers of the original network was implemented. A study of the resulting spiking network architectures was carried out using the Free Spoken Digits dataset, consisting of 3000 audio recordings corresponding to 10 classes of digits from 0 to 9. Conclusion. It is shown that the proposed method of organizing connections for the selected spiking neural network allows reducing the number of connections by up to 60% compared to a fully connected architecture. At the same time, the accuracy of solving the classification problem does not deteriorate and is 0.92...0.95 according to the F1 metric. This matches the accuracy of standard support vector machine, k-nearest neighbor, and random forest classifiers. The source code for this article is publicly available: https://github.com/sag111/Sparse-WTA-SNN

    Resumption of Short-term Burn Reconstruction Missions to Ukraine in Light of COVID-19: A Paradigm Shift

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    The COVID-19 pandemic has disrupted the lives of billions of people globally. Some medical systems continue to be overburdened due to the viral illness leading to incredible public health challenges domestically as well as abroad. However, with vaccination distribution increasing globally, many are pushing for a return to some form of normalcy. In the medical community, some are weighing the risks of returning to global health missions and considering protective strategies to minimize risk of viral spread. Here, we describe our experience in returning to an annual burn reconstruction mission in a low- and middle-income country. We have successfully carried out a return surgical mission trip. Our team of 10 individuals was able to perform over 75 procedures on 25 pediatric patients in 4 operative days. We applied a variety of protective strategies and altered mission protocol to limit exposure and transmission risk while focusing heavily on education and training. Additionally, we increased the use of telemedicine and eliminated typical in-person clinic visits. We increased operative complexity to increase impact while limiting patient exposure. Rigorous perioperative safety and follow-up protocols were implemented. The increased use of telemedicine, reduction of in-person visits, emphasis on education, and implementation of safety and follow-up protocols have led to an improvement in efficiency, safety, and accountability. Our adaptations have provided guidance on responsibly resuming surgical outreach missions, with changes that are likely to endure beyond the COVID-19 pandemic
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