580 research outputs found
Modelling the efficiency of the use of production and investment resources at the regional level : the case of Russia
Purpose: The aim of this article is to examine the efficiency of the use of production and investment resources at the regional level in the Russian Federation. Design/Methodology/Approach: The important feature of the suggested approach is to take into account the average (normative) return of sectoral resources by computing the efficiency scores of regions. Methods of agent-based modelling (ABM) were applied in the investigation using the ‘gravity effects’ that described the behaviour of agent-enterprises. Moreover, agent-investors regarding agent-regions are considered. Findings: The key findings are: (1) There is a significant inequality and a gap between the leading regions of Russia (such as Moscow, Moscow Oblast and Saint Petersburg) and other regions. At the same time, many non-leading regions are more stable and attractive; (2) A complex classification of Russian regions based on solving four tasks, namely the ‘ratio of production to labour’, ‘ratio of production to assets’, ‘ratio of investments to labour’ and ‘ratio of investments to assets’ is an effective approach to estimate region states; (3) In the leading regions e.g., Moscow, has decreasing efficiency scores after 2014, which is probably due to the large influence of crisis phenomena on the largest Russian agglomerations in comparison with other regions; (4) The ‘gravity model’ explains the behaviour of economic agents and allows forecasting the number of regional enterprises and investors. Practical implications: The developed method can be practically applied for other countries with non-homogeneous regional economies. Originality/Value: For the first time the dynamical model of the efficiency of the use of production and investment resources at the regional level of Russia is suggested. Such model allows examining regional changes.peer-reviewe
Optimal Investment in the Development of Oil and Gas Field
Let an oil and gas field consists of clusters in each of which an investor
can launch at most one project. During the implementation of a particular
project, all characteristics are known, including annual production volumes,
necessary investment volumes, and profit. The total amount of investments that
the investor spends on developing the field during the entire planning period
we know. It is required to determine which projects to implement in each
cluster so that, within the total amount of investments, the profit for the
entire planning period is maximum.
The problem under consideration is NP-hard. However, it is solved by dynamic
programming with pseudopolynomial time complexity. Nevertheless, in practice,
there are additional constraints that do not allow solving the problem with
acceptable accuracy at a reasonable time. Such restrictions, in particular, are
annual production volumes. In this paper, we considered only the upper
constraints that are dictated by the pipeline capacity. For the investment
optimization problem with such additional restrictions, we obtain qualitative
results, propose an approximate algorithm, and investigate its properties.
Based on the results of a numerical experiment, we conclude that the developed
algorithm builds a solution close (in terms of the objective function) to the
optimal one
Клапансохраняющие операции на аортальном клапане и восходящей аорте при радикальной коррекции врожденных и приобретенных пороков сердца. Непосредственные результаты
This paper presents the immediate outcomes of valve-sparing operations on the aortic valve and ascending aorta in radical correction of congenital and acquired heart disease. Materials and methods. The study enrolled 50 patients with aortic insufficiency who were operated upon at Shumakov National Medical Research Center of Transplantology and Artificial Organs from 2011 to 2019. The mean age was 48 ± 16 years, 64% of them were men (n = 32). The study included patients with tricuspid (n = 36, 72%) and bicuspid (n = 14, 28%) aortic valves. Aortic valve reimplantation was performed in 32 (64%) patients, aortic root remodeling - in 1 (2%). 17 (34%) patients had no aortic root reconstruction or remodeling. Aortic valve reimplantation was done in 4 (8%) cases in combination with coronary artery bypass grafting, and in 4 (8%) with mitral and tricuspid valve repair. Results. Thirty-day mortality was 0%. In 1 case (2%), a permanent pacemaker was installed due to complete atrioventricular block. There were no neurological and coronary events, and cases of endocarditis. In all patients (100%), aortic valve insufficiency after surgical correction did not exceed grade 1 according to echocardiographic follow-up examination. On aortic valve mean and peak gradients were 8 ± 6 and 15 ± 7 mm Hg, respectively. Findings. Type I and II valve-sparing reconstructive surgery (for bicuspid and tricuspid aortic valves) is an excellent alternative to prosthetic repair with great postoperative outcomes, low valve-associated complications and low mortality. В данной статье представлены непосредственные результаты клапансохраняющих операций на аортальном клапане и восходящей аорте при радикальной коррекции врожденных и приобретенных пороков сердца. Материалы и методы. В исследование вошли 50 пациентов с аортальной недостаточностью, оперированных в нашем центре с 2011-го по 2019 г. Средний возраст составил 48 ± 16 лет, 64% мужчины (n = 32). В исследование вошли пациенты с трехстворчатым (n = 36; 72%) и двустворчатым (n = 14; 28%) аортальным клапаном. Реимплантация аортального клапана выполнена у 32 (64%) пациентов, ремоделирование корня аорты - у 1 (2%). Без реконструкции и ремоделирования корня аорты - 17 (34%) пациентов. В сочетании с коронарным шунтированием - 4 (8%), с пластикой митрального и трикуспидального клапанов - 4 (8%). Результаты. Летальных случаев за период в 30 дней не наблюдали. В 1 случае (2%) в связи с полной атриовентрикулярной блокадой был установлен постоянный электрокардиостимулятор. Неврологических и коронарных событий, а также случаев возникновения эндокардита не наблюдали. У всех пациентов (100%) недостаточность на аортальном клапане после хирургической коррекции по данным эхокардиографического исследования не превышала 1-й степени. На аортальном клапане средний и пиковый градиент составили 8 ± 6 и 15 ± 7 мм рт. ст. соответственно. Выводы. Реконструктивная хирургия с сохранением нативных створок I и II типа, как двустворчатых, так и трехстворчатых аортальных клапанов является прекрасной альтернативой протезированию с отличными послеоперационными результатами, с низкими клапанассоциированными осложнениями и низкой смертностью
New model for system of mesoscopic Josephson contacts
Quantum fluctuations of the phases of the order parameter in 2D arrays of
mesoscopic Josephson junctions and their effect on the destruction of
superconductivity in the system are investigated by means of a quantum-cosine
model that is free of the incorrect application of the phase operator. The
proposed model employs trigonometric phase operators and makes it possible to
study arrays of small superconducting granules, pores filled with superfluid
helium, or Josephson junctions in which the average number of particles
(effective bosons, He atoms, and so on) is small, and the standard approach
employing the phase operator and the particle number operator as conjugate ones
is inapplicable. There is a large difference in the phase diagrams between
arrays of macroscopic and mesoscopic objects for and ( is
the characteristic interaction energy of the particle per granule and is
the Josephson coupling constant). Reentrant superconductivity phenomena are
discussed.Comment: 4 pages, 3 Postscript figure
Contemplation as a Special Psychological Phenomenon and a Form of Self-Therapy
Созерцание представляется важной составной частью ментальных процессов, состояний, а также свойств личности, не совпадая полностью ни с одним из базисных психических процессов. Особенностью процесса созерцания является его фактическое осознание индивидом как особого состояния, при том что не вполне осознается содержание созерцания и его трехчастная структура (предсозерцание, собственно созерцание и постсозерцание). Функциональной особенностью созерцания является внутренняя, скрытая переработка либо коррекция или трансформация микро-, мезо- и макросмыслов жизнедеятельности человека. Немаловажно также то, что этот процесс переосмысления, согласно полученным данным, весьма эмоционально позитивен для индивида. Процесс созерцания можно квалифицировать так же, как спонтанную психологическую самотерапию личности.Contemplation seems to be an important component of mental processes, states, and personality traits, not completely coinciding with any of the basic mental processes. A feature of the process of contemplation is its actual awareness by the individual as a special state, despite the fact that the content of contemplation and its tripartite structure (pre-contemplation, contemplation proper and post-contemplation) are not fully realized. A functional feature of contemplation is the internal, hidden processing, or correction or transformation of micro-, meso- and macro-meanings of human life. It is also important that this process of rethinking, according to the data obtained, is very emotionally positive for the individual. The process of contemplation can also be qualified as a spontaneous psychological self-therapy of the individual
Performance of the Electromagnetic Calorimeter of the HERMES Experiment
The performance of the electromagnetic calorimeter of the HERMES experiment
is described. The calorimeter consists of 840 radiation resistant F101
lead-glass counters. The response to positrons up to 27.5 GeV, the comparison
between the measured energy and the momentum reconstructed from tracking,
long-term stability, hadron rejection and neutral meson invariant mass
reconstruction are shown.Comment: 22 pages, 13 figures, LaTeX, accepted by NI
Mechanism, dynamics, and biological existence of multistability in a large class of bursting neurons
Multistability, the coexistence of multiple attractors in a dynamical system,
is explored in bursting nerve cells. A modeling study is performed to show that
a large class of bursting systems, as defined by a shared topology when
represented as dynamical systems, is inherently suited to support
multistability. We derive the bifurcation structure and parametric trends
leading to multistability in these systems. Evidence for the existence of
multirhythmic behavior in neurons of the aquatic mollusc Aplysia californica
that is consistent with our proposed mechanism is presented. Although these
experimental results are preliminary, they indicate that single neurons may be
capable of dynamically storing information for longer time scales than
typically attributed to nonsynaptic mechanisms.Comment: 24 pages, 8 figure
Transverse-target-spin asymmetry in exclusive -meson electroproduction
Hard exclusive electroproduction of mesons is studied with the
HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and
electron beams off a transversely polarized hydrogen target. The amplitudes of
five azimuthal modulations of the single-spin asymmetry of the cross section
with respect to the transverse proton polarization are measured. They are
determined in the entire kinematic region as well as for two bins in photon
virtuality and momentum transfer to the nucleon. Also, a separation of
asymmetry amplitudes into longitudinal and transverse components is done. These
results are compared to a phenomenological model that includes the pion pole
contribution. Within this model, the data favor a positive
transition form factor.Comment: DESY Report 15-14
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