35 research outputs found

    A flaring X-ray pulsar in Dorado

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    A study of unusual gamma-ray bursts detected on March 5 and March 6, 1979 in the KONUS experiment on the Venera 11 and Venera 12 spacecraft shows their source to be flaring X-ray pulsar in Dorado

    Genome assembly using quantum and quantum-inspired annealing

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    Recent advances in DNA sequencing open prospects to make whole-genome analysis rapid and reliable, which is promising for various applications including personalized medicine. However, existing techniques for {\it de novo} genome assembly, which is used for the analysis of genomic rearrangements, chromosome phasing, and reconstructing genomes without a reference, require solving tasks of high computational complexity. Here we demonstrate a method for solving genome assembly tasks with the use of quantum and quantum-inspired optimization techniques. Within this method, we present experimental results on genome assembly using quantum annealers both for simulated data and the ϕ\phiX 174 bacteriophage. Our results pave a way for an increase in the efficiency of solving bioinformatics problems with the use of quantum computing and, in particular, quantum annealing. We expect that the new generation of quantum annealing devices would outperform existing techniques for {\it de novo} genome assembly. To the best of our knowledge, this is the first experimental study of de novo genome assembly problems both for real and synthetic data on quantum annealing devices and quantum-inspired techniques.Comment: 9 pages, 4 figure

    OPPORTUNITY ESTIMATION OF OPTICAL METHOD APPLICATION IN PROBLEM OF KINEMATIC CHARACTERISTICS REGISTRATION OF DYNAMIC INDENTING PROCESS

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    Subject of Research. A stereoscopic method of technical vision is proposed for recording the kinematic characteristics of the dynamic indentation process in determining the physico-mechanical properties of materials. The proposed method makes it possible to determine the values of the indenter motion speed with high accuracy. Method. The method is based on the use of two high-speed video cameras immovably fixed on one flat platform. Cameras allow for synchronous recording of the indentation process. The objectives and orientation of cameras in the stereo system provide intersection of the visual fields and the required depth of the image space field. Measurement of the movement speed is performed by triangulation method. The distance between the conjugate points of the recorded object on the stereo images is inversely proportional to the distance between the pair of cameras and the corresponding point of the object in the three-dimensional space. Based on the analysis of images obtained by spatially separated cameras, the coordinates of the object point are determined. Main Results. The experimental setup consisted of two high-speed monochrome camcorders Evercam 4000-32-M, rigidly fixed through stereo. Synchronous recording was kept at a speed of 4000 frames/s with a resolution of 1280 × 860 pixels. The indenter was made in the form of a steel ball with a mass of 230 g with a diameter of 38 mm and fell onto an aluminum disk 10 mm thick from a height of 310 mm. Video images from cameras were transferred to a personal computer for processing. The analysis of the obtained data was carried out in the MATLAB system with the help of a specially written software module. The sensitivity of the proposed method made it possible to determine confidently the values of the maximum approach speed of a steel ball equal to 2.39 m/s and a rebound velocity of 1.2 m/s. The random component of the method error did not exceed 2.5%. Practical Relevance. The development of this approach will enable to create high-precision sensors of dynamic indentation. The research results may be of interest to specialists involved in metrological support and non-destructive testing of materials and products in various fields of engineering and construction

    Multifractality in Time Series

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    We apply the concepts of multifractal physics to financial time series in order to characterize the onset of crash for the Standard & Poor's 500 stock index x(t). It is found that within the framework of multifractality, the "analogous" specific heat of the S&P500 discrete price index displays a shoulder to the right of the main peak for low values of time lags. On decreasing T, the presence of the shoulder is a consequence of the peaked, temporal x(t+T)-x(t) fluctuations in this regime. For large time lags (T>80), we have found that C_{q} displays typical features of a classical phase transition at a critical point. An example of such dynamic phase transition in a simple economic model system, based on a mapping with multifractality phenomena in random multiplicative processes, is also presented by applying former results obtained with a continuous probability theory for describing scaling measures.Comment: 22 pages, Revtex, 4 ps figures - To appear J. Phys. A (2000

    Population genomics of the Wolbachia endosymbiont in Drosophila melanogaster

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    Wolbachia are maternally-inherited symbiotic bacteria commonly found in arthropods, which are able to manipulate the reproduction of their host in order to maximise their transmission. Here we use whole genome resequencing data from 290 lines of Drosophila melanogaster from North America, Europe and Africa to predict Wolbachia infection status, estimate cytoplasmic genome copy number, and reconstruct Wolbachia and mtDNA genome sequences. Complete Wolbachia and mitochondrial genomes show congruent phylogenies, consistent with strict vertical transmission through the maternal cytoplasm and imperfect transmission of Wolbachia. Bayesian phylogenetic analysis reveals that the most recent common ancestor of all Wolbachia and mitochondrial genomes in D. melanogaster dates to around 8,000 years ago. We find evidence for a recent incomplete global replacement of ancestral Wolbachia and mtDNA lineages, which is likely to be one of several similar incomplete replacement events that have occurred since the out-of-Africa migration that allowed D. melanogaster to colonize worldwide habitats.Comment: 41 pages, 5 figure

    A thalamic reticular networking model of consciousness

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    <p>Abstract</p> <p>[Background]</p> <p>It is reasonable to consider the thalamus a primary candidate for the location of consciousness, given that the thalamus has been referred to as the gateway of nearly all sensory inputs to the corresponding cortical areas. Interestingly, in an early stage of brain development, communicative innervations between the dorsal thalamus and telencephalon must pass through the ventral thalamus, the major derivative of which is the thalamic reticular nucleus (TRN). The TRN occupies a striking control position in the brain, sending inhibitory axons back to the thalamus, roughly to the same region where they receive afferents.</p> <p>[Hypotheses]</p> <p>The present study hypothesizes that the TRN plays a pivotal role in dynamic attention by controlling thalamocortical synchronization. The TRN is thus viewed as a functional networking filter to regulate conscious perception, which is possibly embedded in thalamocortical networks. Based on the anatomical structures and connections, modality-specific sectors of the TRN and the thalamus appear to be responsible for modality-specific perceptual representation. Furthermore, the coarsely overlapped topographic maps of the TRN appear to be associated with cross-modal or unitary conscious awareness. Throughout the latticework structure of the TRN, conscious perception could be accomplished and elaborated through accumulating intercommunicative processing across the first-order input signal and the higher-order signals from its functionally associated cortices. As the higher-order relay signals run cumulatively through the relevant thalamocortical loops, conscious awareness becomes more refined and sophisticated.</p> <p>[Conclusions]</p> <p>I propose that the thalamocortical integrative communication across first- and higher-order information circuits and repeated feedback looping may account for our conscious awareness. This TRN-modulation hypothesis for conscious awareness provides a comprehensive rationale regarding previously reported psychological phenomena and neurological symptoms such as blindsight, neglect, the priming effect, the threshold/duration problem, and TRN-impairment resembling coma. This hypothesis can be tested by neurosurgical investigations of thalamocortical loops via the TRN, while simultaneously evaluating the degree to which conscious perception depends on the severity of impairment in a TRN-modulated network.</p

    ТРАНСПЛАНТИРОВАННОЕ СЕРДЦЕ. ПРАВОЖЕЛУДОЧКОВАЯ НЕДОСТАТОЧНОСТЬ, ОТТОРЖЕНИЕ ИЛИ МИОКАРДИТ?

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    The differentiation of the cases of the right ventricular failure in transplanted heart should be complex and challenging. The 28-year old man with dilated cardiomyopathy underwent orthotopic heart transplantation. After transplantation developed right ventricular failure. The biopsy (n = 5) didn’t reveal any signs of myocardial rejection. There were noted some signs of inflammation in lateral right ventricular wall only by gated SPECT. The right ventricular failure increased and 6 months later there was successfully performed the heart retransplantation on the patient. The virusological study revealed the Epstein–Barr virus in myocardium. The explanted heart research excluded limphoproliferative disease by immunogystochemical tests. The final diagnosis is myocarditis. Дифференцирование причин правожелудочковой недостаточности пересаженного сердца должно быть комплексным. Мужчина 28 лет с дилатационной кардиомиопатией был подвергнут ортотопической трансплантации сердца. После трансплантации развилась прогрессирующая правожелудочковая недо- статочность. Биопсия (в количестве 5) не выявила признаков отторжения миокарда. Только при gated SPECT были отмечены признаки воспаления в боковой стенке ПЖ. Правожелудочковая недостаточность нарастала, и спустя 6 месяцев больному успешно была выполнена ретрансплантация сердца. Вирусоло- гическое исследование выявило наличие вируса Эпштейна–Барр в миокарде. Иммуногистохимические исследования эксплантированного сердца исключили лимфопролиферативное заболевание. Заключи- тельный диагноз – миокардит.

    Increased risk of severe clinical course of COVID-19 in carriers of HLA-C*04:01

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    BACKGROUND: Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, there has been increasing urgency to identify pathophysiological characteristics leading to severe clinical course in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human leukocyte antigen alleles (HLA) have been suggested as potential genetic host factors that affect individual immune response to SARS-CoV-2. We sought to evaluate this hypothesis by conducting a multicenter study using HLA sequencing. METHODS: We analyzed the association between COVID-19 severity and HLAs in 435 individuals from Germany ((n) = 135), Spain ((n) = 133), Switzerland ((n) = 20) and the United States ((n) = 147), who had been enrolled from March 2020 to August 2020. This study included patients older than 18 years, diagnosed with COVID-19 and representing the full spectrum of the disease. Finally, we tested our results by meta-analysing data from prior genome-wide association studies (GWAS). FINDINGS: We describe a potential association of HLA-C*04:01 with severe clinical course of COVID-19. Carriers of HLA-C*04:01 had twice the risk of intubation when infected with SARS-CoV-2 (risk ratio 1.5 [95% CI 1.1-2.1], odds ratio 3.5 [95% CI 1.9-6.6], adjusted (p)-value = 0.0074). These findings are based on data from four countries and corroborated by independent results from GWAS. Our findings are biologically plausible, as HLA-C*04:01 has fewer predicted bindings sites for relevant SARS-CoV-2 peptides compared to other HLA alleles. INTERPRETATION: HLA-C*04:01 carrier state is associated with severe clinical course in SARS-CoV-2. Our findings suggest that HLA class I alleles have a relevant role in immune defense against SARS-CoV-2

    Consensus Paper: Towards a Systems-Level View of Cerebellar Function: the Interplay Between Cerebellum, Basal Ganglia, and Cortex

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