312 research outputs found

    Artistic creativity of martiros saryan as the indicator of national self-identification of the personality in a multicultural space: features of methodology of a retrospective research

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    In this article, the life and works of the famous Armenian artist, founder of the modern Armenian school of painting Martiros Saryan (1880-1972) are analyzed in the context of the influence of Russian and Armenian culture during the Russian period of his activity. In this retrospective analysis of the life and works of the artist, it is proposed to use the new indicator, which is Russian or the Middle East countries place names being included in the titles of works by the artist. On the basis of the analysis of Russian archival sources and the analytical research of content, it is established that, in Russia, the interest of the artist during the first period of his life and study was mainly on subjects reflecting the life of the Armenian diaspora in the south of Russia. Landscapes were mainly represented against the background in which the artist spent his childhood. During the time which he spent in Moscow, interest in Russian culture was connected with the recognition of the contribution of teachers of the School of Painting, Sculpture and Architecture in the development of the Russian art school and world culture. Saryan has shown the aspiration to seize this particular technic of painting, at the same time he had the original vision of the world. Keywords: methodology, personality, geographical indicators, Martiros Saryan, culture,regional archiv

    On the coexistence of position and momentum observables

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    We investigate the problem of coexistence of position and momentum observables. We characterize those pairs of position and momentum observables which have a joint observable

    Barycentric decomposition of quantum measurements in finite dimensions

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    We analyze the convex structure of the set of positive operator valued measures (POVMs) representing quantum measurements on a given finite dimensional quantum system, with outcomes in a given locally compact Hausdorff space. The extreme points of the convex set are operator valued measures concentrated on a finite set of k \le d^2 points of the outcome space, d< \infty being the dimension of the Hilbert space. We prove that for second countable outcome spaces any POVM admits a Choquet representation as the barycenter of the set of extreme points with respect to a suitable probability measure. In the general case, Krein-Milman theorem is invoked to represent POVMs as barycenters of a certain set of POVMs concentrated on k \le d^2 points of the outcome space.Comment: !5 pages, no figure

    Causes of Microcephaly in the Zika Era in Argentina: A Retrospective Study

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    There are gaps in understanding the causes and consequences of microcephaly. This paper describes the epidemiological characteristics, clinical presentations, and etiologies of children presenting microcephaly during the Zika outbreak in Argentina. This observational retrospective study conducted in the pediatric hospital of Juan P. Garrahan reviewed the medical records of 40 children presenting microcephaly between March 2017 and November 2019. The majority (60%) were males and born full-term. At first evaluation, microcephaly was defined as congenital (31/40, 77%) and associated with other features (68%) such as seizures, developmental delay, non-progressive chronic encephalopathy, and West Syndrome. It was found manifestations restricted to central nervous system (55%), ocular (8/40, 20%), and acoustic (9/40, 23%) defects, and abnormal neuroimaging findings (31/39, 79%). Non-infectious diseases were the primary cause of isolated microcephaly (21/37, 57%), largely related to genetic diseases (13/21, 62%). Only 3 were children were diagnosed with Congenital Zika infection (3/16, 7.5%)

    Convergent evidences from human and animal studies implicate angiotensin I-converting enzyme activity in cognitive performance in schizophrenia

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    In schizophrenia (SCZ), higher angiotensin I-converting enzyme (ACE) levels have been reported in patient's blood and cerebrospinal fluid (CSF). Hereby, we propose to explore whether the ACE activity levels are associated to cognitive performance in SCZ. Seventy-two patients with SCZ or schizoaffective disorder diagnosis, and 69 healthy controls (HCs) underwent a cognitive battery with parallel collection of peripheral blood samples to measure ACE activity. Significant higher ACE activity levels were confirmed in the plasma of SCZ patients compared with HCs (Student's t=−5.216; P<0.001). ACE activity significantly correlated to Hopkins delayed recall measures (r=−0.247; P=0.004) and Hopkins total (r=−0.214; P=0.012). Subjects grouped as high ACE activity (above average) had worse performance compared with low ACE activity level group for Hopkins delayed recall measure, even after correction for clinical condition, age, gender and years of education (P=0.029). The adjusted R squared for this final model was 0.343. This result was evident only comparing extreme groups for ACE activity, when splitting the sample in three groups with similar number of subjects. To clarify this finding, we performed an evaluation of the cognitive performance of transgenic mice with three copies of ACE gene in novel object recognition (NOR) test, which showed that such animals presented impairment in NOR (P<0.05) compared with two copies of wild-type animals. The results observed in SCZ patients and animal model suggest both the association of ACE to cognitive deficits in SCZ. This finding may support the evaluation of novel treatment protocols and/or of innovative drugs for specific intervention of cognitive deficits in SCZ envisioning concomitant ACE activity and behavior evaluations

    Spreading of a Macroscopic Lattice Gas

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    We present a simple mechanical model for dynamic wetting phenomena. Metallic balls spread along a periodically corrugated surface simulating molecules of liquid advancing along a solid substrate. A vertical stack of balls mimics a liquid droplet. Stochastic motion of the balls, driven by mechanical vibration of the corrugated surface, induces diffusional motion. Simple theoretical estimates are introduced and agree with the results of the analog experiments, with numerical simulation, and with experimental data for microscopic spreading dynamics.Comment: 19 pages, LaTeX, 9 Postscript figures, to be published in Phy. Rev. E (September,1966

    Nanohertz Frequency Determination for the Gravity Probe B HF SQUID Signal

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    In this paper, we present a method to measure the frequency and the frequency change rate of a digital signal. This method consists of three consecutive algorithms: frequency interpolation, phase differencing, and a third algorithm specifically designed and tested by the authors. The succession of these three algorithms allowed a 5 parts in 10^10 resolution in frequency determination. The algorithm developed by the authors can be applied to a sampled scalar signal such that a model linking the harmonics of its main frequency to the underlying physical phenomenon is available. This method was developed in the framework of the Gravity Probe B (GP-B) mission. It was applied to the High Frequency (HF) component of GP-B's Superconducting QUantum Interference Device (SQUID) signal, whose main frequency fz is close to the spin frequency of the gyroscopes used in the experiment. A 30 nHz resolution in signal frequency and a 0.1 pHz/sec resolution in its decay rate were achieved out of a succession of 1.86 second-long stretches of signal sampled at 2200 Hz. This paper describes the underlying theory of the frequency measurement method as well as its application to GP-B's HF science signal.Comment: The following article has been submitted to Review of Scientific Instruments. After it is published, it will be found at (http://rsi.aip.org/

    Bohrification of operator algebras and quantum logic

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    Following Birkhoff and von Neumann, quantum logic has traditionally been based on the lattice of closed linear subspaces of some Hilbert space, or, more generally, on the lattice of projections in a von Neumann algebra A. Unfortunately, the logical interpretation of these lattices is impaired by their nondistributivity and by various other problems. We show that a possible resolution of these difficulties, suggested by the ideas of Bohr, emerges if instead of single projections one considers elementary propositions to be families of projections indexed by a partially ordered set C(A) of appropriate commutative subalgebras of A. In fact, to achieve both maximal generality and ease of use within topos theory, we assume that A is a so-called Rickart C*-algebra and that C(A) consists of all unital commutative Rickart C*-subalgebras of A. Such families of projections form a Heyting algebra in a natural way, so that the associated propositional logic is intuitionistic: distributivity is recovered at the expense of the law of the excluded middle. Subsequently, generalizing an earlier computation for n-by-n matrices, we prove that the Heyting algebra thus associated to A arises as a basis for the internal Gelfand spectrum (in the sense of Banaschewski-Mulvey) of the "Bohrification" of A, which is a commutative Rickart C*-algebra in the topos of functors from C(A) to the category of sets. We explain the relationship of this construction to partial Boolean algebras and Bruns-Lakser completions. Finally, we establish a connection between probability measure on the lattice of projections on a Hilbert space H and probability valuations on the internal Gelfand spectrum of A for A = B(H).Comment: 31 page

    Corresponding States of Structural Glass Formers

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    The variation with respect to temperature T of transport properties of 58 fragile structural glass forming liquids (68 data sets in total) are analyzed and shown to exhibit a remarkable degree of universality. In particular, super-Arrhenius behaviors of all super-cooled liquids appear to collapse to one parabola for which there is no singular behavior at any finite temperature. This behavior is bounded by an onset temperature To above which liquid transport has a much weaker temperature dependence. A similar collapse is also demonstrated, over the smaller available range, for existing numerical simulation data.Comment: 6 pages, 2 figures. Updated References, Table Values, Submitted for Publicatio
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