721 research outputs found
An ADAF in the Kerr metric: propagation of a wave pattern
Time evolution of an advection-dominated accretion flow is explored in terms
of relativistic fluid equations. An axially symmetric, vertically averaged mean
flow is constructed and then perturbed. An axisymmetric pattern is followed as
it propagates in the form of a wave towards the horizon of a rotating (Kerr)
black hole. Several assumptions are relaxed in comparison with previous works
(Manmoto et al. 1996).Comment: Accepted for publication in PASJ, scheduled for October 200
Measuring time perspective in adolescents : can you get the right answer by asking the wrong questions?
Time perspective continues to evolve as a psychological construct. The extant literature suggests that higher future orientation and lower present orientation are associated with better developmental outcomes. However, the extant literature also suggests that issues remain with the measurement of the construct. Recently, a 25-item version of the Zimbardo Time Perspective Inventory (ZTPI-25) was suggested for use based on high internal consistency estimates and good discriminant validity of scores in a sample of Italian adolescents. However, the genesis of this scale is uncertain. The present study examined the factorial validity, reliability, and concurrent validity of ZTPI-25 scores in Slovenian, American, and British adolescents. Results revealed satisfactory concurrent validity based on correlations with measures used in the development of the full ZTPI. However, internal consistency and factorial validity of scores were unsatisfactory. The present study questions the use of the ZTPI-25 with adolescents in the context of conceptual and measurement issues more broadly
FEM modeling of magnetic microwire and its using for stress monitoring inside the composite beam
The proposed article is devoted to the stress evaluation inside the composite beam using the embedded magnetic microwire sensors. The interlaminar stresses with high values can occur inside the composite structures during the operation. It is essential to monitor the stresses and to increase the lifetime of the composite materials by prediction using the research results from the stress distribution estimation and also during the operation using the embedded magnetic microwire-based sensors. In the article the results of the mechanical stress distribution between the magnetic microwire coating and core and the discussion about the experimental application of the magnetic microwire inside the composite beam are presented
High-rate low-temperature dc pulsed magnetron sputtering of photocatalytic TiO2films: the effect of repetition frequency
The article reports on low-temperature high-rate sputtering of hydrophilic transparent TiO2thin films using dc dual magnetron (DM) sputtering in Ar + O2mixture on unheated glass substrates. The DM was operated in a bipolar asymmetric mode and was equipped with Ti(99.5) targets of 50 mm in diameter. The substrate surface temperature Tsurfmeasured by a thermostrip was less than 180 °C for all experiments. The effect of the repetition frequency frwas investigated in detail. It was found that the increase of frfrom 100 to 350 kHz leads to (a) an improvement of the efficiency of the deposition process that results in a significant increase of the deposition rate aDof sputtered TiO2films and (b) a decrease of peak pulse voltage and sustaining of the magnetron discharge at higher target power densities. It was demonstrated that several hundreds nm thick hydrophilic TiO2films can be sputtered on unheated glass substrates at aD = 80 nm/min, Tsurf < 180 °C when high value of fr = 350 kHz was used. Properties of a thin hydrophilic TiO2film deposited on a polycarbonate substrate are given
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Security and Performance Trade-offs for Data Distribution Service in Flying Ad-Hoc Networks
This paper focuses on the data distribution service(DDS) middleware and its publish/subscribe logic - a topic thathas recently regained popularity in both academia as well asindustry. DDS is a well-known approach based on publish-subscribe logic. Therefore, only brief introduction of the issueis given followed by practical evaluation of current, availableand real implementations from the security and performancepoint of view. The analysis and evaluation is performed toaid comparison of competing DDS implementation, and thuscould serve well as an input to decision-making about whichof these solutions is best suited for a given situation. Finally,the practical performance evaluation is performed via severaldifferent scenarios to effectively compare the currently most-usedDDS implementations
E-cadherin and cell adhesion: a role in architecture and function in the pancreatic islet
Background/Aims: The efficient secretion of insulin from beta-cells requires extensive intra-islet communication. The cell surface adhesion protein epithelial (E)-cadherin (ECAD) establishes and maintains epithelial tissues such as the islets of Langerhans. In this study, the role of ECAD in regulating insulin secretion from pseudoislets was investigated. Methods: The effect of an immuno-neutralising ECAD on gross morphology, cytosolic calcium signalling, direct cell-to-cell communication and insulin secretion was assessed by fura-2 microfluorimetry, Lucifer Yellow dye injection and insulin ELISA in an insulin-secreting model system. Results: Antibody blockade of ECAD reduces glucose-evoked changes in [Ca2+](i) and insulin secretion. Neutralisation of ECAD causes a breakdown in the glucose-stimulated synchronicity of calcium oscillations between discrete regions within the pseudoislet, and the transfer of dye from an individual cell within a cell cluster is attenuated in the absence of ECAD ligation, demonstrating that gap junction communication is disrupted. The functional consequence of neutralising ECAD is a significant reduction in insulin secretion. Conclusion: Cell adhesion via ECAD has distinct roles in the regulation of intercellular communication between beta-cells within islets, with potential repercussions for insulin secretion. Copyright (C) 2007 S. Karger AG, Basel
The focused ion beam as an integrated circuit restructuring tool
One of the capabilities of focused ion beam systems is ion milling. The purpose of this work is to explore this capability as a tool for integrated circuit restructuring. Methods for cutting and joining conductors are needed. Two methods for joining conductors are demonstrated. The first consists of spinning nitrocellulose (a selfâdeveloping resist) on the circuit, ion exposing an area, say, 7Ă7 ÎŒm, then milling a smaller via with sloping sidewalls through the first metal layer down to the second, eâbeam evaporating metal, and then dissolving the nitrocellulose to achieve liftoff. The resistance of these links between two metal levels varied from 1 to 7 Ω. The second, simpler method consists of milling a via with vertical sidewalls down to the lower metal layer, then reducing the milling scan to a smaller area in the center of this via, thereby redepositing the metal from the lower layer on the vertical sidewall. The short circuit thus achieved varied from 0.4 to 1.5 Ω for vias of dimensions 3Ă3 ÎŒm to 1Ă1 ÎŒm, respectively. The time to mill a 1Ă1 ÎŒm via with a 68 keV Ga+ beam, of 220 Pa current is 60 s. In a system optimized for this application, this milling time is expected to be reduced by a factor of at least 100. In addition, cuts have been made in 1âÎŒmâthick Al films covered by 0.65 ÎŒm of SiO2. These cuts have resistances in excess of 20 MΩ. This method of circuit restructuring can work at dimensions a factor of 10 smaller than laser zapping and requires no special sites to be fabricated
Channelling figurativity through narrative : the paranarrative in fiction and non-fiction
Contrary to wide-spread assumptions, metaphor in narrative is not a pre-established, extra-textual form appearing in different instances of discourse, but rather an event resulting from a strategic distribution of information in the narrative process. Hence, the appeal to conceptual cultural knowledge is to be considered as a consequence, and not as a prerequisite of metaphor interpretation. By means of the concept of the paranarrative, we highlight the rhetorical interconnectedness of metaphor with other figures of speech (such as metonymy) and we explore the narrative integration of diacritic forms of indirectness. In order to illustrate the terminology that can address these focal concerns, the paper discusses the relation between tropes and narrative, via selected examples from narrative texts (both fictional and non-fictional) written by Juli Zeh, Herta MĂŒller, JĂŒrgen Nieraad, and Siddhartha Mukherjee. As their common denominator, these examples channel through narrative figurative domains considered to be known intuitively to wit: personifications; iconic pars pro toto references to concentration camps; and metaphors for cancer in disease biographies
An unfolding signifier: London's Baltic Exchange in Tallinn
In the summer of 2007 an unusual cargo arrived at Muuga and Paldiski harbors outside Tallinn. It consisted of nearly 50 containers holding over 1,000 tons of building material ranging from marble columns, staircases and fireplaces, to sculpted allegorical figures, wooden paneling and old-fashioned telephone booths. They were once part of the Baltic Exchange in the City of London. Soon they will become facets of the landscape of Tallinn. The following article charts this remarkable story and deploys this fragmented monument to analyze three issues relating to the Estonian capital: the relocation of the âBronze Soldierâ, the demolition of the Sakala Culture Center, and Tallinnâs future role as European Cultural Capital in 2011
Atomic-scale representation and statistical learning of tensorial properties
This chapter discusses the importance of incorporating three-dimensional
symmetries in the context of statistical learning models geared towards the
interpolation of the tensorial properties of atomic-scale structures. We focus
on Gaussian process regression, and in particular on the construction of
structural representations, and the associated kernel functions, that are
endowed with the geometric covariance properties compatible with those of the
learning targets. We summarize the general formulation of such a
symmetry-adapted Gaussian process regression model, and how it can be
implemented based on a scheme that generalizes the popular smooth overlap of
atomic positions representation. We give examples of the performance of this
framework when learning the polarizability and the ground-state electron
density of a molecule
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