566 research outputs found

    Digital Image Compression Using Artificial Neural Networks

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    The problem of storing, transmitting, and manipulating digital images is considered. Because of the file sizes involved, large amounts of digitized image information are becoming common in modern projects. Our goal is to described an image compression transform coder based on artificial neural networks techniques (NNCTC). A comparison of the compression results obtained from digital astronomical images by the NNCTC and the method used in the compression of the digitized sky survey from the Space Telescope Science Institute based on the H-transform is performed in order to assess the reliability of the NNCTC

    Endocannabinoid Metabolome of Human Breast Milk

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    Human breast milk (HBM) is an extremely complex yet fascinating biofluid tailored to meet an infant’s nutritional requirements for development. Amongst the nutrients present in HBM, the long-chain polyunsaturated fatty acids (LCPUFAs) are of high importance due to the pivotal role they play in infant cognitive and visual development, and growth. In addition, the LCPUFAs are precursors to endocannabinoids (EC) which are endogenous lipid mediators. EC exert metabolic responses including appetite and food intake regulation, and they have been identified to play a role in establishing the suckling response of the newborn that is needed to nurse. Thus, we aimed to characterize and quantify the EC present in HBM, termed the EC metabolome (ECM). HBM samples were collected from two different populations, one in Guatemala (n = 26) and the other one in the United States (n = 24). We collected HBM at different lactation stages: transitional (2 weeks postpartum) and mature (4 weeks and 16-24 weeks postpartum) milk. Using liquid chromatography-mass spectrometry analyses, we identified 15 members of the ECM in both lactation stages: arachidonoylethanolamine, palmitoylethanolamine, oleoylethanolamine, docosahexaenoylethanolamine, eicoapentaenoylethanolamine, eicosenoylethanolamine, arachidonoylglycerol, palmitoyglycerol, oleoylglycerol, docosahexaenoylglycerol, eicosapentaenoylglycerol, eiconenooylglycerol, arachidonic acid, docosahexaenoic acid, and eicosapentaenoic acid. Overall, members in the glycerol group were higher in concentration than those of the ethanolamide group. To date, the mechanisms of action and the role of the ECM in HBM and infant development are not fully understood. Data from the present study provides a foundation to develop future studies to help elucidate how the ECM modulates infant health and development

    Simultaneous Identification of the Diffusion Coefficient and the Potential for the Schr\"odinger Operator with only one Observation

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    This article is devoted to prove a stability result for two independent coefficients for a Schr\"odinger operator in an unbounded strip. The result is obtained with only one observation on an unbounded subset of the boundary and the data of the solution at a fixed time on the whole domain

    Місце інформаційних прав у системі прав людини

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    Гайтан В. В. Місце інформаційних прав у системі прав людини / В. В. Гайтан // Актуальні проблеми держави і права : зб. наук. пр. / редкол.: С. В. Ківалов (голов. ред.), В. М. Дрьомін (заст. голов. ред.), Ю. П. Аленін [та ін.] ; МОНмолодьспорт України, НУ «ОЮА». – Одеса : Юрид. л-ра, 2012. – Вип. 68. - С. 103-109.З розвитком міжнародного законодавства все більш актуальним стає питання захисту прав людини у сфері інформації. Досвід зарубіжних країн показує, що інформаційні права набувають все більшого розповсюдження в системі поколінь прав людини. Для кращого розуміння сутності і значимості інформаційних прав необхідними є належне законодавче закріплення, створення нормативної бази, а також їх філософське осмислення

    Microscopic Analysis of the Non-Dissipative Force on a Line Vortex in a Superconductor: Berry's Phase, Momentum Flows and the Magnus Force

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    A microscopic analysis of the non-dissipative force Fnd{\bf F}_{nd} acting on a line vortex in a type-II superconductor at T=0T=0 is given. We first examine the Berry phase induced in the true superconducting ground state by movement of the vortex and show how this induces a Wess-Zumino term in the hydrodynamic action ShydS_{hyd} of the superconducting condensate. Appropriate variation of ShydS_{hyd} gives Fnd{\bf F}_{nd} and variation of the Wess-Zumino term is seen to contribute the Magnus (lift) force of classical hydrodynamics to Fnd{\bf F}_ {nd}. This first calculation confirms and strengthens earlier work by Ao and Thouless which was based on an ansatz for the many-body ground state. We also determine Fnd{\bf F}_{nd} through a microscopic derivation of the continuity equation for the condensate linear momentum. This equation yields the acceleration equation for the superflow and shows that the vortex acts as a sink for the condensate linear momentum. The rate at which momentum is lost to the vortex determines Fnd{\bf F}_{nd} and the result obtained agrees with the Berry phase calculation. The Magnus force contribution to Fnd{\bf F}_{nd} is seen to be a consequence of the vortex topology. Preliminary remarks are made regarding finite temperature extensions, with emphasis on its relevance to the sign anomaly occurring in Hall effect experiments done in the flux flow regime.Comment: 40 pages, RevTex, UBCTP-94-00

    Berry's Phase in the Presence of a Stochastically Evolving Environment: A Geometric Mechanism for Energy-Level Broadening

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    The generic Berry phase scenario in which a two-level system is coupled to a second system whose dynamical coordinate is slowly-varying is generalized to allow for stochastic evolution of the slow system. The stochastic behavior is produced by coupling the slow system to a heat resevoir which is modeled by a bath of harmonic oscillators initially in equilibrium at temperature T, and whose spectral density has a bandwidth which is small compared to the energy-level spacing of the fast system. The well-known energy-level shifts produced by Berry's phase in the fast system, in conjunction with the stochastic motion of the slow system, leads to a broadening of the fast system energy-levels. In the limit of strong damping and sufficiently low temperature, we determine the degree of level-broadening analytically, and show that the slow system dynamics satisfies a Langevin equation in which Lorentz-like and electric-like forces appear as a consequence of geometrical effects. We also determine the average energy-level shift produced in the fast system by this mechanism.Comment: 29 pages, RevTex, submitted to Phys. Rev.

    Порушення прав людини в соціальних мережах (класифікаційний аналіз)

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    Гайтан В. В. Порушення прав людини в соціальних мережах (класифікаційний аналіз) / В. В. Гайтан // Правове життя сучасної України : матеріали Міжнар. наук. конф. проф.-викл. та аспірант. складу (м. Одеса, 16-17 травня 2013 р.) / відп. за вип. В. М. Дрьомін ; НУ "ОЮА". Півд. регіон. центр НАПрН України. - Одеса : Фенікс, 2013. - Т. 1. - С. 43-45

    The effects of varying colour-luminosity relations on supernova science

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    The success of Type Ia supernova (SN Ia) distance standardisation for cosmology relies on a single global linear relationship between their peak luminosity and colour, the β\beta parameter. However, there are several pieces of evidence and physical reasons to believe that this relation is not universal and may change within different subgroups, or even among individual objects. In this work, we allow β\beta to vary among subpopulations with different observed properties in the cosmological fits. Although the inferred cosmological parameters are consistent with previous studies that assume a single colour-luminosity relation, we find that the SN data favour nonuniversal distributions of β\beta when split according to SN colour and/or host-galaxy mass. For galaxy mass, we obtain a β\beta-step relation in which low β\beta values occur in more massive galaxies, a trend that can be explained by differing dust reddening laws for two types of environments. For colour, we find that bluer/redder SNe Ia are consistent with a lower/larger β\beta. This trend is explained with β\beta being a combination of a low intrinsic colour-luminosity relation dominant in bluer SNe and a higher extrinsic reddening relation dominant at redder colours. The host galaxy mass-step correction always provides better distance calibration, regardless of the multiple β\beta approaches, and we suggest that it may come from a difference in intrinsic colour-luminosity properties of SNe Ia in two types of environments. Additionally, we find that blue SNe in low-mass environments are better standard candles than the others.Comment: 11 pages, 7 figures, 2 tables. Accepted in MNRA

    Effects of Noise, Correlations and errors in the preparation of initial states in Quantum Simulations

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    In principle a quantum system could be used to simulate another quantum system. The purpose of such a simulation would be to obtain information about problems which cannot be simulated with a classical computer due to the exponential increase of the Hilbert space with the size of the system and which cannot be measured or controlled in an actual experiment. The system will interact with the surrounding environment, with the other particles in the system and be implemented using imperfect controls making it subject to noise. It has been suggested that noise does not need to be controlled to the same extent as it must be for general quantum computing. However the effects of noise in quantum simulations and how to treat them are not completely understood. In this paper we study an existing quantum algorithm for the one-dimensional Fano-Anderson model to be simulated using a liquid-state NMR device. We calculate the evolution of different initial states in the original model, and then we add interacting spins to simulate a more realistic situation. We find that states which are entangled with their environment, and sometimes correlated but not necessarily entangled have an evolution which is described by maps which are not completely positive. We discuss the conditions for this to occur and also the implications.Comment: Revtex 4-1, 14 pages, 21 figures, version 2 has typos corrected and acknowledgement adde
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