650 research outputs found
Genetic algorithms with DNN-based trainable crossover as an example of partial specialization of general search
Universal induction relies on some general search procedure that is doomed to
be inefficient. One possibility to achieve both generality and efficiency is to
specialize this procedure w.r.t. any given narrow task. However, complete
specialization that implies direct mapping from the task parameters to
solutions (discriminative models) without search is not always possible. In
this paper, partial specialization of general search is considered in the form
of genetic algorithms (GAs) with a specialized crossover operator. We perform a
feasibility study of this idea implementing such an operator in the form of a
deep feedforward neural network. GAs with trainable crossover operators are
compared with the result of complete specialization, which is also represented
as a deep neural network. Experimental results show that specialized GAs can be
more efficient than both general GAs and discriminative models.Comment: AGI 2017 procedding, The final publication is available at
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Limits of using the results of polygraph testing in criminal procedure
An offer for restrictions, concerning the limits of use of polygraph testing results as orientation information at pre-trial stages of criminal proceedings, was made in this articl
Differential neutron energy spectra measured on spacecraft low Earth orbit
Two methods for measuring neutrons in the range from thermal energies to dozens of MeV were used. In the first method, alpha-particles emitted from the (sup 6) Li(n.x)T reaction are detected with the help of plastic nuclear track detectors, yielding results on thermal and resonance neutrons. Also, fission foils are used to detect fast neutrons. In the second method, fast neutrons are recorded by nuclear photographic emulsions (NPE). The results of measurements on board various satellites are presented. The neutron flux density does not appear to correlate clearly with orbital parameters. Up to 50% of neutrons are due to albedo neutrons from the atmosphere while the fluxes inside the satellites are 15-20% higher than those on the outside. Estimates show that the neutron contribution to the total equivalent radiation dose reaches 20-30%
Changes of the body functions during long-term hypokinesia
Prolonged hypokinesis (100-170 days) studied in 2000 rats kept in cages limiting their mobility provoked considerable changes in the gaseous and energetic metabolism: an elevation of the total gaseous metabolism and of the rate of O2 requirement by the muscles (in the late periods of hypokinesis) and a change in the intensity of tissue respiration of the liver and myocardium. There also proved to be a reduction in the level of phosphorylation and separation of oxidative phosphorylation in the myocardium, liver, and partially in the skeletal muscle. Prolonged hypokinesia led to changes in tissue metabolism: a disturbance of development of the animals, a marked delay and an increase in the weight of the organism and the muscular system, and disturbances of the mineral and protein metabolism. Prolonged hypokinesis also lead to exhaustion of the hypothalamus-hypophysis-adrenal cortex system
Chiari malformation - modern aspects of diagnostics and treatment
The review presents modern ideas about morphology of afterbrain malformations - Chiari, type I. Main criteria of introscopic diagnistics of Chiari malformation of type I and of combined anomalies of development of craniovertebral articulation are discussed. The theories of pathogenesis of craniocervical dysplasias of afterbrain and development of intramedullary cavities are presented. The criteria of differential diagnostics of hydromyelia and syringomyelia and also modern methods of surgical treatment of bone and neural dysplasias are determined. Main clinical features of the course of disease that appears in mosaic picture of cerebellum affection, caudal group of craniocerebral nerves, medulla, brain hemispheres and spine cord are revealed, the characteristics of the mostfrequent syndromes is given. The reconstruction of anatomic symmetry of cone and neural structures of craniocervical articular and restoration of circulation of cerebrospinal fluid through outcomes of the IV ventricle guarantees favorable results of treatment. Promptly and adequately performed operation at the pathology of afterbrail allows to prevent development of irreversible and low-curable morphofunctional defects of neural system
Neutron influences and energy spectra in the Cosmos-2044 biosatellite orbit
Joint Soviet-American measurements of the neutron component of space radiation (SR) were carried out during the flight of the Soviet biosatellite Cosmos-2044. Neutron flux densities and differential energy spectra were measured inside and on the external surface of the spacecraft. Three energy intervals were employed: thermal (E(sub n) less than or equal to 0.2 eV), resonance (0.2 eV less than E(sub n) less than 1.0 MeV) and fast (E(sub n) greater than or equal to 1.0 MeV) neutrons. The first two groups were measured with U.S. (6)LiF detectors, while fast neutrons were recorded both by U.S. fission foils and Soviet nuclear emulsions. Estimations were made of the contributions to absorbed and equivalent doses from each neutron energy interval and a correlation was presented between fast neutron fluxes, measured outside the satellite, and the phase of solar activity (SA). Average dose equivalent rates of 0.018 and 0.14 mrem d(exp -1) were measured for thermal and resonance neutrons, respectively, outside the spacecraft. The corresponding values for fast neutrons were 3.3 (U.S.) and 1.8 (U.S.S.R.) mrem d(exp -1). Inside the spacecraft, a value of 3.5 mrem d(exp -1) was found
A Clinical Case of Surgical Treatment of the Adjacent Segment of the Spine during Fusion
Every year, the number of operations on the lumbar spine with the use of various spinal fusion techniques increases, which leads to an increase in the number of cases in the long-term period of surgical treatment, the formation of pathology of the adjacent segment (ASP), which is part of the structure of the failed back surgery syndrome (FBSS). It is known that the pathology of the adjacent segment is a general term and covers two concepts: the degeneration of the adjacent segment (ASDeg) and the disease of the adjacent segment (ASDis). ASDeg is represented by radiographic changes occurring in the adjacent spinal motion segments during spinal surgery with spinal fusion, and ASDis refers to the clinical symptoms that develop during radiographic changes in these segments. With the pathology of an adjacent segment, clinically significant degenerative changes in it are not always formed. If these X-ray changes are formed and correlate with clinical and neurological manifestations, then surgical treatment is indicated. This pathology can be treated with repeated surgical intervention, which this article demonstrate with the clinical example of surgical treatment of the adjacent segment of the spine during fusion
Analysis of complications and unsatisfactory results of surgical treatment of degenerative lumbar spinal stenosis in the elderly patients
Background. The results of treatment of the elderly patients operated for spinal stenosis allow us to suggest that a cascade of degenerative changes in the spinal motion segments causes the formation of an adjacent level syndrome, pseudarthrosis, and in some cases – the instability in the fixing structure.The aim of the study. To determine the prognostic factors for the adjacent level syndrome in patients after decompressive and stabilizing spinal surgeries.Methods. We carried out a retrospective cohort study of the surgical treatment of 129 elderly patients (over 60 years of age) for the period from January 2018 to March 2022, who underwent surgery at the lumbosacral level of spine for degenerative spinal stenosis.Results. The outcomes of surgical treatment of 129 patients and the results of discriminant analysis of morphometric studies of computed tomography data indicate that the most significant indicators for the development of the adjacent level syndrome are the lordosis angle in the segment adjacent to the operated one (the mean value in the analyzed group is 12.87 ± 2.22°; in the control group – 11.92 ± 2.97°); the anterior height of the adjacent intervertebral disc (the mean value in the analyzed group is 12.70 ± 2.44 mm; in the control group – 11.46 ± 3.58 mm) and the difference of anterior and posterior disc heights at the adjacent level (the mean value in the analyzed group is 5.48 ± 2.84 mm; in the control group – 6.27 ± 2.71 mm).Conclusion. When analyzing the treatment outcomes of 129 elderly patients operated for degenerative spinal stenosis using instrumented spinal fusion, we revealed that in 16 patients, the adjacent level syndrome developed with an increase in the lordosis angle at the level adjacent to the operated segment. An increase in the anterior height of the adjacent intervertebral disc and the decrease in the difference of anterior and posterior disc heights at the adjacent level can be considered as unfavorable prognostic factors (p = 0.83)
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