1,721,058 research outputs found
Role of Syndecan-4 in the cellular invasion of Orientia tsutsugamushi
No full textCell surface heparan sulfate proteoglycans (HSPGs) play a critical role in the cellular invasion of intracellular bacteria and are presumed to have a role in the infection of host cells by Orientia tsutsugamushi. Previously, we showed that O. tsutsugamushi infection decreased markedly after treating host cells with heparinase, which suggests that HSPGs play an important role in oriential infection. We tested oriential infection in REF-Syn4 cells over-expressing syndecan-4, and in REF-Syn4AS cells in which the expression of syndecan-4 was down regulated by transfecting with anti-sense syndecan-4 cDNA. Oriential infection was found to be dependent on the expression level of syndecan-4 on the cell surface. Furthermore, the infectivity of O. tsutsugamushi was specifically reduced by treating O. tsutsugamushi with the purified recombinant core protein of syndecan-4 (Syn4E). These results suggest that the core protein of syndecan-4 and the heparin/heparan sulfate chain of syndecan play an important role in oriential infection by O. tsutsugamushi. (C) 2004 Elsevier Ltd. All rights reserved.N
Inherent background coefficients for acoustic resonance scattering from submerged, multilayered, cylindrical structures
No full textFor the scattering of acoustic waves by an elastic shell, the acoustical background coefficients are inherent in the scattering coefficients. The background coefficients for elastic empty shells, named the inherent background, can be obtained from the zero frequency limit of the modal accelerance in the scattering coefficients for analogous liquid shells, In this work, the concept of obtaining the inherent background is applied to multilayered elastic cylindrical structures. The inherent background manifests itself in the sound scattering by the liquid structures. The scattering S-function and the modal accelerance for the liquid system an determined by considering the incoming and outgoing waves, The accelerance of liquid layers is generalized so that the scattering function can be obtained by the recurrence relation for the accelerances of the adjacent liquid layers. From the zero frequency limit of the generalized accelerance of liquid structures, the constant modal accelerance is extracted and the general expression for the inherent background coefficients is obtained. The background coefficients depend on the densities of the layers and ambient fluid medium, the relative thickness of each layer, and the normal mode number. The acoustical background coefficients for solid cylinders, empty shells,fluid-filled shells, and double-layered shells can be obtained by the appropriate limit of the density ratio and the relative thickness of layers in the generalized inherent background coefficients. The usefulness of the proposed background is demonstrated for several examples of layered structures. (C) 1998 Acoustical Society of America. [S0001-4966(98)03302-5]
Automatic partial parsing rule acquisition using decision tree induction
No full textPartial parsing techniques try to recover syntactic information efficiently and reliably by sacrificing completeness and depth of analysis. One of the difficulties of partial parsing is finding a means to extract the grammar involved automatically. In this paper, we present a method for automatically extracting partial parsing rules from a tree-annotated corpus using decision tree induction. We define the partial parsing rules as those that can decide the structure of a substring in an input sentence deterministically. This decision can be considered as a classification; as such, for a substring in an input sentence, a proper structure is chosen among the structures occurred in the corpus. For the classification, we use decision tree induction, and induce partial parsing rules from the decision tree. The acquired grammar is similar to a phrase structure grammar, with contextual and lexical information, but it allows building structures of depth one or more. Our experiments showed that the proposed partial parser using the automatically extracted rules is not only accurate and efficient, but also achieves reasonable coverage for Korean
Extracting partial parsing rules from tree-annotated corpus: Toward deterministic global parsing
No full textIt is not always possible to find a global parse for an input sentence owing to problems such as errors of a sentence, incompleteness of lexicon and grammar. Partial parsing is an alternative approach to respond to these problems. Partial parsing techniques try to recover syntactic information efficiently and reliably by sacrificing completeness and depth of analysis. One of the difficulties in partial parsing is how the grammar might be automatically extracted. In this paper we present a method of automatically extracting partial parsing rules from a tree-annotated corpus using the decision tree method. Our goal is deterministic global parsing using partial parsing rules, in other words, to extract partial parsing rules with higher accuracy and broader expansion. First, we define a rule template that enables to learn a subtree for a given substring, so that the resultant rules can be more specific and stricter to apply. Second, rule candidates extracted from a training corpus are enriched with contextual and lexical information using the decision tree method and verified through cross-validation. Last, we underspecify non-deterministic rules by merging substructures with ambiguity in those rules. The learned grammar is similar to phrase structure grammar with contextual and lexical information, but allows building structures of depth one or more. Thanks to automatic learning, the partial parsing rules can be consistent and domain-independent. Partial parsing with this grammar processes an input sentence deterministically using longest-match heuristics, and recursively applies rules to an input sentence. The experiments showed that the partial parser using automatically extracted rules is not only accurate and efficient but also achieves reasonable coverage for Korean
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Experimental study on the convective heat transfer coefficient of early-age concrete
No full textDuring the process of setting and hardening in concrete, the temperature profile shows a gradual nonlinear distribution due to the development of heat of hydration in cement. At early ages of concrete structures, this nonlinear distribution can have a large influence on crack evolution. It is thus important to obtain an accurate temperature history, and to do this, it is necessary to examine the thermal properties of the concrete. in this study, the convective heat transfer coefficient, which represents the heat transfer between a concrete surface and ambient air, was experimentally investigated with test variables such as the velocity of wind, the curing conditions, and the ambient temperature. For analyses using the thermal equilibrium boundary condition, it is generally noted that most of the heat release by the evaporation of moisture occurs at an early stage. To consider this phenomenon, the existing thermal equilibrium boundary condition has been modified so as to consider the evaporation quantity due to the evaporation effect. Convective heat transfer coefficients for a specific case were then calculated from the modified thermal equilibrium boundary condition using experimental results. (c) 2008 Elsevier Ltd. All rights reserved
A three-dimensional distributed source modeling and direction of arrival estimation using two linear arrays
No full textA number of results on the estimation of direction of arrival have been obtained based on the assumption that the signal sources are point sources. Recently, it has been shown that signal source localization can be accomplished more adequately with distributed source models in some real surroundings. In this paper, we consider modeling of three-dimensional distributed signal sources, in which a source location is represented by the center angles and degrees of dispersion. We address estimation of the elevation and azimuth angles of distributed sources based on the proposed distributed source modeling in the three-dimensional space using two linear arrays. Some examples are included to more explicitly show the estimation procedures under the model: numerical results obtained by a MUSIC-based method with two uniform linear arrays are discussed.Korea Research Foundation (KRF) under Grant KRF-2000-041-E00231
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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