2,574 research outputs found
Distributed resource discovery using a context sensitive infrastructure
Distributed Resource Discovery in a World Wide Web environment using full-text indices will never scale. The distinct properties of WWW information (volume, rate of change, topical diversity) limits the scaleability of traditional approaches to distributed Resource Discovery. An approach combining metadata clustering and query routing can, on the other hand, be proven to scale much better. This paper presents the Content-Sensitive Infrastructure, which is a design building on these results. We also present an analytical framework for comparing scaleability of different distribution strategies
On the generalized continuity equation
A generalized continuity equation extending the ordinary continuity equation
has been found using quanternions. It is shown to be compatible with Dirac,
Schrodinger, Klein-Gordon and diffusion equations. This generalized equation is
Lorentz invariant. The transport properties of electrons are found to be
governed by Schrodinger-like equation and not by the diffusion equation.Comment: 9 Latex pages, no figure
Elucidating the structural composition of a Fe-N-C catalyst by nuclear and electron resonance techniques
FeāNāC catalysts are very promising materials for fuel cells and metalāair batteries. This work gives fundamental insights into the structural composition of an FeāNāC catalyst and highlights the importance of an inādepth characterization. By nuclearā and electronāresonance techniques, we are able to show that even after mild pyrolysis and acid leaching, the catalyst contains considerable fractions of Ī±āiron and, surprisingly, iron oxide. Our work makes it questionable to what extent FeN4 sites can be present in FeāNāC catalysts prepared by pyrolysis at 900āĀ°C and above. The simulation of the iron partial density of phonon states enables the identification of three FeN4 species in our catalyst, one of them comprising a sixfold coordination with endāon bonded oxygen as one of the axial ligands
Upper respiratory tract infections and general anaesthesia in children
Conflicting reports regarding the hazards of anaesthesia in children presenting for surgery with an upper respiratory tract infection have appeared in the literature. In the present study 130 children undergoing general anaesthesia with face mask for myringotomy and grommet insertion were graded as having either an acute or recent upper respiratory tract infection or were asymptomatic according to predetermined clinical symptoms and signs. The severity of respiratory and related complications were scored during induction, emergence and recovery. The peripheral oxygen saturation was recorded during induction, emergence, transfer to the recovery ward and in the recovery ward itself. There were no significant differences (p > 0.05) in the complication scores between the three groups of children. However, the incidence of hypoxaemia (oxygen saturation Ā± 93%) was significantly greater during transfer in the acute infection group (p = 0.001) and the recent infection group (p = 0.02), as well as during recovery in the acute group (p = 0.03) compared with asymptomatic children.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75689/1/j.1365-2044.1992.tb02389.x.pd
Frequency-wavenumber spectrum of the free surface of shallow turbulent flows over a rough boundary
Data on the frequency-wavenumber spectra and dispersion relation of the dynamic water surface in an open channel flow are very scarce. In this work, new data on the frequency-wavenumber spectra were obtained in a rectangular laboratory flume with a rough bottom boundary, over a range of subcritical Froude numbers. These data were used to study the dispersion relation of the surface waves in such shallow turbulent water flows. The results show a complex pattern of surface waves, with a range of scales and velocities. When the mean surface velocity is faster than the minimum phase velocity of gravity-capillary waves, the wave pattern is dominated by stationary waves that interact with the static rough bed. There is a coherent three-dimensional pattern of radially propagating waves with the wavelength approximately equal to the wavelength of the stationary waves. Alongside these waves, there are freely propagating gravity-capillary waves that propagate mainly parallel to the mean flow, both upstream and downstream. In the flow conditions where the mean surface velocity is slower than the minimum phase velocity of gravity-capillary waves, patterns of non-dispersive waves are observed. It is suggested that these waves are forced by turbulence. The results demonstrate that the free surface carries information about the underlying turbulent flow. The knowledge obtained in this study paves the way for the development of novel airborne methods of non-invasive flow monitoring
Paleomagnetism of Cryogenian Kitoi mafic dykes in South Siberia: Implications for Neoproterozoic paleogeography
We present a new paleomagnetic pole of 1.1Ā°N, 22.4Ā°E, A95 = 7.4Ā° from the 760 Ma gabbro-dolerite Kitoi dykes located in the southern part of the Siberian Craton. The pole is supported by contact tests and suggests closer position of Siberia relative to Laurentia at 760 Ma than in Mesoproterozoic. We propose that this closer configuration was achieved by dextral transpressive motion of Siberia relative to Laurentia between 780 and 760 Ma. This motion was probably initiated at the first stage of the Rodinia breakup and is coeval with the 780 Ma Gunbarrel magmatic event of the western Canadian shield
The Scottish economy [July 1981]
The current economic situation is extremely depressed and recent events suggest that, without significant increases in economic activity, the political and social fabric of this country may be several strained. However, as argued in the UK section, the prospects for recovery are bleak and reliance on a purely financial strategy to restore growth is in itself inadequate. The source of real economic growth lies in the ability of labour, capital and enterprise to come together in a manner conducive to increased productivity over time. It is therefore worthwhile examining these factors of production to determine the effect of current policies upon them
Review of the quarter's economic trends [October 1981]
In the second quarter of 1981 the index of industrial production for the United Kingdom was 8% below its level for the corresponding period in 1980. This notwithstanding, there do appear to be signs that the bottom of the output trough may now have been reached. This brief section will seek to understand the latest UK and world economic data to determine current economic conditions and forecasts future trends
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