191 research outputs found

    Detectability of large correlation length inflationary magnetic field with Cherenkov telescopes

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    Magnetic fields occupying the voids of the large scale structure may be a relic from the Early Universe originating from either Inflation or from cosmological phase transitions. We explore the possibility of identifying the inflationary origin of the void magnetic fields and measuring its parameters with gamma-ray astronomy methods. The large correlation length inflationary field is expected to impose a characteristic asymmetry of extended gamma-ray emission that is correlated between different sources on the sky. We show that a set of nearby blazars for which the extended emission is observable in the 0.1-1 TeV band with CTA can be used for the test of inflationary origin of the void magnetic fields.Comment: 8 pages, 6 figures, accepted to JET

    Constraint on intergalactic magnetic field from Fermi/LAT observations of the "pair echo" of GRB 221009A

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    Delayed "pair echo" signal from interactions of very-high-energy gamma rays in the intergalactic medium can be used for detection of the inter-galactic magnetic field (IGMF). We use the data of Fermi/LAT telescope coupled with LHAASO observatory measurements to confirm the presence of IGMF along the line of sight to the gamma-ray burst GRB221009A. Comparing the Fermi/LAT measurements with the expected level of the pair echo flux, set by the multi-TeV LHAASO detection, we derive a lower bound 101910^{-19} G on the IGMF with correlation length ll larger than 1 Mpc, improving as l1/2l^{-1/2} for shorter correlation lengths. This provides an independent verification of existence of a lower bound on IGMF in the voids of the Large Scale Structure, previously derived from the observations of active galactic nuclei.Comment: 4 pages, 2 figue

    Scheduling problems for mobile cloud computing

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    Nowadays the popularity of mobile devices is rapidly increased. New facilities of them (Wi-Fi, GPS, high speed processors etc.) allows to improve mobile applications in commerce, learning, gaming, health monitoring, sports etc. But really there are several reasons that limit mobile computing: limited storage capacity, limited battery life and limited processing power of mobile devices. This paper is dedicated to Mobile cloud computing (MCC). We consider MCC as combination of mobile and cloud computing where both data storage and data processing are performed outside the mobile device but inside the cloud

    Optical properties of colloidal solutions of metal nanoparticles

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    nanoparticles, spectroscopy, light absorption, plasmon, plasmon resonanceNanoparticles are finding more practical applications in various fields of human activity, including veterinary and medicine. Due to the fact that the effectiveness of colloidal solutions of nanoparticles is directly related to their aggregate state, convenient methods for assessing the physicochemical characteristics of such preparations is of high priority. Nanoparticles have unique optical properties that depend on their size and shape. They can be determined by the refractive index of light on the surface of nanoparticles in a phenomenon known as plasmon resonance, which makes the UV-Vis spectroscopy a valuable tool for studying and evaluating the properties of nanomaterials. Optical characteristics of NPs colloidal solutions of noble metals (silver) or bioelements (copper, silicon dioxide) were determined at various wavelengths (nm): 300–800 nm. The surface plasmon resonance has been found in all test preparations, while all of them exhibited obvious nonlinear optical properties. The most pronounced plasmon resonance peak was found in the colloidal solution of silver NPs within a wavelength of 420 nm. In the case of a colloidal solution of copper NPs, the peak of plasmon resonance was less pronounced and had a red shift (peak at 560 nm). In the colloidal solution of silicon dioxide, the plasmon resonance was less pronounced than in other test preparations, being shifted to the blue side of the spectrum (360 nm). UV-Vis spectroscopy of metal NPs requires further studies to assess their stability and influence of various external factors on their activity

    Results of the Application of the Original Method of Surgical Treatment of Patients with Severe Hallux Valgus

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    Background. Traditional methods of surgical treatment of severe Hallux valgus (HV) lead to a large number of complications and poor results. In order to avoid complications and improve the quality of treatment, an original technique of double osteotomy of the first metatarsal bone has been proposed.The aim of the study was to conduct a comparative assessment of the results of applying the original technique in the treatment of patients with severe Hallux valgus.Materials and methods. A retrospective analysis of the treatment of 95 patients operated on at the Seversk Clinical Hospital for severe Hallux valgus in the period from 2008 to 2016 was performed. The study group included 60 patients who underwent surgery according to the original method. In a comparison group of 35 people, Logroshino's surgery was performed. Clinical, radiological, surgical and statistical research methods were used.Results. The final assessment of the results 1 year after the operation showed an unacceptably high number of Hallux valgus relapses, complications, and unsatisfactory results in the comparison group. The use of original approachesfor osteotomy of the first metatarsal bone in patients of the study group allowed to significantly improve treatment results and achieve good results in 85 % of cases.Conclusion. The proposed surgical technique is effective and shows statistically significantly better results 1 year after surgery. Application of the original technique will improve the results of surgical correction of the severe degree of Hallux valgus, which consists in reducing the number of complications and improving functional indicators

    Stem Cells and Neuroprotection: Understanding the Players

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    The use of neuroprotective therapies begs the question of how such therapies could affect preexisting stem cell populations within the host, as well as those introduced through cell-replacement therapy. Multiple mechanisms may mediate stem cell responses to neuroprotectants such as host/donor age and gender, cellular lineage/differentiation status, and mitochondrial dynamics. Current therapeutic sources for stem cells are embryonic, somatic, or induced pluripotent, with very little known about the effects of gender, age, cell type, and mitochondrial dynamics. With the advent of therapies to stimulate and recruit endogenous stem cells or transplant donor cells into damage areas in the hopes of recuperative regeneration of lost neurons, it is important to discuss mechanisms that dictate the winning players in the neuroprotection game. This review will focus on our current understanding of the characteristics of renewing stem cells that may affect neuroprotection

    The Large High Altitude Air Shower Observatory (LHAASO) Science White Paper

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    The Large High Altitude Air Shower Observatory (LHAASO) project is a new generation multi-component instrument, to be built at 4410 meters of altitude in the Sichuan province of China, with the aim to study with unprecedented sensitivity the spec trum, the composition and the anisotropy of cosmic rays in the energy range between 1012^{12} and 1018^{18} eV, as well as to act simultaneously as a wide aperture (one stereoradiant), continuously-operated gamma ray telescope in the energy range between 1011^{11} and 101510^{15} eV. The experiment will be able of continuously surveying the TeV sky for steady and transient sources from 100 GeV to 1 PeV, t hus opening for the first time the 100-1000 TeV range to the direct observations of the high energy cosmic ray sources. In addition, the different observables (electronic, muonic and Cherenkov/fluorescence components) that will be measured in LHAASO will allow to investigate origin, acceleration and propagation of the radiation through a measurement of energy spec trum, elemental composition and anisotropy with unprecedented resolution. The remarkable sensitivity of LHAASO in cosmic rays physics and gamma astronomy would play a key-role in the comprehensive general program to explore the High Energy Universe. LHAASO will allow important studies of fundamental physics (such as indirect dark matter search, Lorentz invariance violation, quantum gravity) and solar and heliospheric physics. In this document we introduce the concept of LHAASO and the main science goals, providing an overview of the project.Comment: This document is a collaborative effort, 185 pages, 110 figure
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