314 research outputs found

    Гарантоздатність як фундаментальний узагальнюючий та інтегруючий підхід

    Get PDF
    Представлені головні принципи та умови становлення і етапи розвитку фундаментальної теорії і практики узагальнюючих та інтегруючих концепцій гарантоздатності, починаючи з першої об’єднаної конференції двох наукових шкіл Дж. фон Неймана і Н. Вінера. Приведені основні положення розвитку теоретичних засад і результатів прикладних досліджень інтеграційних процесів безвідмовності (надійності), відмовостійкості та гарантоздатності інформаційно-управляючих комп’ютерних систем (ІУКС).Представлены главные принципы, условия становления и этапы развития фундаментальной теории и практики обобщающих и интегрирующих концепций гарантоспособности, начиная с первой объединённой конференции двух научных школ Дж. фон Неймана и Н. Винера. Приведены основные положения развития теоретических основ и результатов прикладных исследований интеграционных процессов безотказности (надёжности), отказоустойчивости и гарантоспособности информационно-управляющих компьютерных систем (ИУКС).The main principles and conditions of formation and stages of development of the fundamental theory and practice of the generalizing and integrating concepts of dependability were presented after the leadthrough the first joint conference of two scientific schools of J. von Neumann and N. Wiener. The basic aspects of development of theoretical principles and results of applied researches of integration processes of reliability (fail-safety)

    Malignant transformation of an abdominal inflammatory myofibroblastic tumor with distant metastases in a child

    Get PDF
    Inflammatory myofibroblastic tumors (IMT) are lesions that mostly affect young adults and children. The tumor is made up of myofibroblasts and a mixed inflammatory infiltrate and rarely undergoes malignant transformation. We present a case of a 13-year-old boy with a pelvic mass diagnosed as IMT which underwent malignant transformation and metastasised to the liver. We report the ultrasound, computed tomography (CT) and magnetic resonance (MR) findings of this rare disorder

    How to recognize inborn errors of immunity in a child presenting with a malignancy: guidelines for the pediatric hemato-oncologist

    Get PDF
    Inborn errors of immunity (IEI) are a group of disorders caused by genetically determined defects in the immune system, leading to infections, autoimmunity, autoinflammation and an increased risk of malignancy. In some cases, a malignancy might be the first sign of an underlying IEI. As therapeutic strategies might be different in these patients, recognition of the underlying IEI by the pediatric hemato-oncologist is important. This article, written by a group of experts in pediatric immunology, hemato-oncology, pathology and genetics, aims to provide guidelines for pediatric hemato-oncologists on how to recognize a possible underlying IEI and what diagnostic tests can be performed, and gives some consideration to treatment possibilities

    Square root singularity in the viscosity of neutral colloidal suspensions at large frequencies

    Full text link
    The asymptotic frequency ω\omega, dependence of the dynamic viscosity of neutral hard sphere colloidal suspensions is shown to be of the form η0A(ϕ)(ωτP)1/2\eta_0 A(\phi) (\omega \tau_P)^{-1/2}, where A(ϕ)A(\phi) has been determined as a function of the volume fraction ϕ\phi, for all concentrations in the fluid range, η0\eta_0 is the solvent viscosity and τP\tau_P the P\'{e}clet time. For a soft potential it is shown that, to leading order steepness, the asymptotic behavior is the same as that for the hard sphere potential and a condition for the cross-over behavior to 1/ωτP1/\omega \tau_P is given. Our result for the hard sphere potential generalizes a result of Cichocki and Felderhof obtained at low concentrations and agrees well with the experiments of van der Werff et al, if the usual Stokes-Einstein diffusion coefficient D0D_0 in the Smoluchowski operator is consistently replaced by the short-time self diffusion coefficient Ds(ϕ)D_s(\phi) for non-dilute colloidal suspensions.Comment: 18 pages LaTeX, 1 postscript figur

    Thixotropy in macroscopic suspensions of spheres

    Get PDF
    An experimental study of the viscosity of a macroscopic suspension, i.e. a suspension for which Brownian motion can be neglected, under steady shear is presented. The suspension is prepared with a high packing fraction and is density-matched in a Newtonian carrier fluid. The viscosity of the suspension depends on the shear rate and the time of shearing. It is shown for the first time that a macroscopic suspension shows thixotropic viscosity, i.e. shear-thinning with a long relaxation time as a unique function of shear. The relaxation times show a systematic decrease with increasing shear rate. These relaxation times are larger when decreasing the shear rates, compared to those observed after increasing the shear. The time scales involved are about 10000 times larger than the viscous time scale and about 1000 times smaller than the thermodynamic time scale. The structure of the suspension at the outer cylinder of a viscometer is monitored with a camera, showing the formation of a hexagonal structure. The temporal decrease of the viscosity under shear coincides with the formation of this hexagonal pattern

    Maximising Synergy among Tropical Plant Systematists, Ecologists, and Evolutionary Biologists

    Get PDF
    Closer collaboration among ecologists, systematists, and evolutionary biologists working in tropical forests, centred on studies within long-term permanent plots, would be highly beneficial for their respective fields. With a key unifying theme of the importance of vouchered collection and precise identification of species, especially rare ones, we identify four priority areas where improving links between these communities could achieve significant progress in biodiversity and conservation science: (i) increasing the pace of species discovery; (ii) documenting species turnover across space and time; (iii) improving models of ecosystem change; and (iv) understanding the evolutionary assembly of communities and biomes
    corecore