3,406 research outputs found

    Slanted matrices, Banach frames, and sampling

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    In this paper we present a rare combination of abstract results on the spectral properties of slanted matrices and some of their very specific applications to frame theory and sampling problems. We show that for a large class of slanted matrices boundedness below of the corresponding operator in p\ell^p for some pp implies boundedness below in p\ell^p for all pp. We use the established resultto enrich our understanding of Banach frames and obtain new results for irregular sampling problems. We also present a version of a non-commutative Wiener's lemma for slanted matrices

    Food balancing assessment : a three-way approach

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    Purpose: The aim of this article is the improvement of the theoretical bases and the development of a scientifically grounded approach balancing the food supply from the economic and the practical application for a complex social and economic assessment of development of the food sphere as a whole. Design/Methodology/Approach: In the process of research the authors’ approach was used to consider the balance of food supply from the position of three structural and consistently interrelated elements-phenomena, process and state. The authors’ interpretation of each element is given, the method of their evaluation is developed, based on the structural division of indicators into balanced ones, exceeding the level of balance and being below the specified level. These indicators are differentiated into 7 functional groups (from the minimum to the maximum degree of balance). Findings: The result is a comparative assessment of the level of balance of food supply in the UK, France, Czech Republic, Latvia and Russia and the definition on its basis of priority directions of development of agriculture in each of the allocated states. Practical Implications: The results of the work can be used by governing bodies to make specific practical decisions in the food sector, and to adjust the directions of its development. Originality/Value: Materials of the article are original and have not been previously published. The calculations were based on official data from the European Statistical Agency, Eurostat and the Federal State Statistics Service of Russia, which indicates the reliability of the presented scientific materials.peer-reviewe

    Наукові підходи до визначення економічного змісту поняття «бюджетний менеджмент» (The scientific approach to determine the economic content of the budget management concept)

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    У статті проаналізовано наукові погляди на тлумачення сутності поняття «бюджетний менеджмент». На основі критичного аналізу та узагальнення існуючих поглядів вітчизняних і зарубіжних дослідників сформульоване власне авторське бачення дефініції бюджетного менеджменту, що ґрунтується на її морфологічній декомпозиції із виділенням мети, завдань, суб’єктів, об’єктів, принципів та функцій бюджетного менеджменту. (In the article it was analyzed the scientific opinions on the interpretation of the essence of the concept of «budget management». On the basis of a critical analysis and synthesis of existing views of domestic and foreign researchers to formulate their own vision of the author’s definition of budget management, which is based on its morphological decomposition, for the purposes of allocation, task, subjects, objects, principles and budget management functions.

    Synthetic prions generated in vitro are similar to a newly identified subpopulation of PrPSc from sporadic Creutzfeldt-Jakob disease

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    In recent studies, the amyloid form of recombinant prion protein (PrP) encompassing residues 89–230 (rPrP 89-230) produced in vitro induced transmissible prion disease in mice. These studies showed that unlike “classical” PrPSc produced in vivo, the amyloid fibrils generated in vitro were more proteinase-K sensitive. Here we demonstrate that the amyloid form contains a proteinase K-resistant core composed only of residues 152/153–230 and 162–230. The PK-resistant fragments of the amyloid form are similar to those observed upon PK digestion of a minor subpopulation of PrPSc recently identified in patients with sporadic Creutzfeldt-Jakob disease (CJD). Remarkably, this core is sufficient for self-propagating activity in vitro and preserves a β-sheet-rich fibrillar structure. Full-length recombinant PrP 23-230, however, generates two subpopulations of amyloid in vitro: One is similar to the minor subpopulation of PrPSc, and the other to classical PrPSc. Since no cellular factors or templates were used for generation of the amyloid fibrils in vitro, we speculate that formation of the subpopulation of PrPSc with a short PK-resistant C-terminal region reflects an intrinsic property of PrP rather than the influence of cellular environments and/or cofactors. Our work significantly increases our understanding of the biochemical nature of prion infectious agents and provides a fundamental insight into the mechanisms of prions biogenesis

    The presence of valine at residue 129 in human prion protein accelerates amyloid formation

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    The polymorphism at residue 129 of the human PRNP gene modulates disease susceptibility and the clinicopathological phenotypes in human transmissible spongiform encephalopathies. The molecular mechanisms by which the effect of this polymorphism are mediated remain unclear. It has been shown that the folding, dynamics and stability of the physiological, alpha-helix-rich form of recombinant PrP are not affected by codon 129 polymorphism. Consistent with this, we have recently shown that the kinetics of amyloid formation do not differ between protein containing methionine at codon 129 and valine at codon 129 when the reaction is initiated from the a-monomeric PrPC-like state. In contrast, we have shown that the misfolding pathway leading to the formation of beta-sheet-rich, soluble oligomer waS favoured by the presence of methionine, compared with valine, at position 129. In the present work, we examine the effect of this polymorphism on the kinetics of an alternative misfolding pathway, that of amyloid formation using partially folded PrP allelomorphs. We show that the valine 129 allelomorph forms amyloids with a considerably shorter lag phase than the methionine 129 allelomorph both under spontaneous conditions and when seeded with pre-formed amyloid fibres. Taken together, our studies demonstrate that the effect of the codon 129 polymorphism depends on the specific misfolding pathway and on the initial conformation of the protein. The inverse propensities of the two allelomorphs to misfold in vitro through the alternative oligomeric and amyloidogenic pathways could explain some aspects of prion diseases linked to this polymorphism such as age at onset and disease incubation time. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved

    Source to source compiler for the automatic parallelization of JavaScript code

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    This work focuses on the development of a source-to-source compiler for the automatic parallelization of JavaScript code. The proposed compiler transforms the input code to an AST (Abstract syntax tree). Afterward, we applied a dependence analysis, followed by fusion and fission techniques. As a later part, new portions of code are inserted to parallelize specific sections of the original program. From the modified AST obtained, we return a new JavaScript code. From our experimentations, we can conclude that our solution reduces the execution time by parallelizing loops, but only if they do not use significant amounts of data, and the complexity of them is not concentrated in a small number of iterations
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