19,080 research outputs found
The British Geological Survey's new Geomagnetic Data Web Service
Increasing demand within the geomagnetism community for high quality real-time or near-real-time observatory data means there is a requirement for data producers to have a robust and scalable data processing infrastructure capable of delivering geomagnetic data products over the Internet in a variety of formats. We describe a new software system, developed at BGS, which will allow access to our geomagnetic data products both within our organisation's intranet and over the Internet. We demonstrate how the system is designed to afford easy access to the data by a wide range of software clients and allow rapid development of software utilizing our observatory data
D1 and D5-Brane Actions in AdS_m x S^n
The kappa-invariant and supersymmetric actions of D1 and D5-branes in AdS_3 x
S^3 are investigated, as well as the action of a D5-brane in an AdS_5 x S^5
background. The action of a D5-brane lying totally in an AdS_3 x S^3 background
is found. Some progress was made towards finding the action for the D5-brane
free to move in the whole AdS_3 x S^3 x T^4 space, however the supersymmetric
action found here is not kappa-invariant and the reasons the method used did
not find a kappa-invariant solution are discussed.Comment: 17pp, Latex, improved explanations, a definition adde
Mode-Coupling Theory of Colloids with Short-range Attractions
Within the framework of the mode-coupling theory of super-cooled liquids, we
investigate new phenomena in colloidal systems on approach to their glass
transitions. When the inter-particle potential contains an attractive part,
besides the usual repulsive hard core, two intersecting liquid-glass transition
lines appear, one of which extends to low densities, while the other one, at
high densities, shows a re-entrant behaviour. In the glassy region a new type
of transition appears between two different types of glasses. The complex
phenomenology can be described in terms of higher order glass transition
singularities. The various glass phases are characterised by means of their
viscoelastic properties. The glass driven by attractions has been associated to
particle gels, and the other glass is the well known repulsive colloidal glass.
These correspondences, in associations with the new predictions of glassy
behaviour mean that such phenomena may be expected in colloidal systems with,
for example, strong depletion or other short-ranged attractive potentials.Comment: 17 pages, 8 figure
Near Infrared Spectroscopy of Young Brown Dwarfs in Upper Scorpius
Spectroscopic follow-up is a pre-requisite for studies of the formation and
early evolution of brown dwarfs. Here we present IRTF/SpeX near-infrared
spectroscopy of 30 candidate members of the young Upper Scorpius association,
selected from our previous survey work. All 24 high confidence members are
confirmed as young very low mass objects with spectral types from M5 to L1,
15-20 of them are likely brown dwarfs. This high yield confirms that brown
dwarfs in Upper Scorpius can be identified from photometry and proper motions
alone, with negligible contamination from field objects (<4%). Out of the 6
candidates with lower confidence, 5 might still be young very low mass members
of Upper Scorpius, according to our spectroscopy. We demonstrate that some very
low mass class II objects exhibit radically different near infrared (0.6 -
2.5micron) spectra from class III objects, with strong excess emission
increasing towards longer wavelengths and partially filled in features at
wavelengths shorter than 1.25micron. These characteristics can obscure the
contribution of the photosphere within such spectra. Therefore, we caution that
near infrared derived spectral types for objects with discs may be unreliable.
Furthermore, we show that the same characteristics can be seen to some extent
in all class II and even a significant fraction of class III objects (~40%),
indicating that some of them are still surrounded by traces of dust and gas.
Based on our spectra, we select a sample of objects with spectral types of M5
to L1, whose near-infrared emission represents the photosphere only. We
recommend the use of these objects as spectroscopic templates for young brown
dwarfs in the future.Comment: 12 pages, 9 figures, Accepted in MNRA
Sensitivity of arrest in mode-coupling glasses to low-q structure
We quantify, within mode coupling theory, how changes in the liquid structure
affect that of the glass. Apart from the known sensitivity to the structure
factor at wavevectors around the first sharp diffraction peak , we
find a strong (and inverted) response to structure at wavevectors \emph{below}
this peak: an increase in {\em lowers} the degree of arrest over a
wide -range. This strong sensitivity to `caged cage' packing effects, on
length scales of order 2d, is much weaker in attractive glasses where
short-range bonding dominates the steric caging effect.Comment: 4 pages, 5 figures. v2: 3 figures replaced; text rewritte
Enhancement and evaluation of Skylab photography for potential land use inventories, part 1
The author has identified the following significant results. Three sites were evaluated for land use inventory: Finger Lakes - Tompkins County, Lower Hudson Valley - Newburgh, and Suffolk County - Long Island. Special photo enhancement processes were developed to standardize the density range and contrast among S190A negatives. Enhanced black and white enlargements were converted to color by contact printing onto diazo film. A color prediction model related the density values on each spectral band for each category of land use to the spectral properties of the various diazo dyes. The S190A multispectral system proved to be almost as effective as the S190B high resolution camera for inventorying land use. Aggregate error for Level 1 averaged about 12% while Level 2 aggregate error averaged about 25%. The S190A system proved to be much superior to LANDSAT in inventorying land use, primarily because of increased resolution
THE EFFECT OF INFLATION ON PRIVATE CONTRACTS: UNITED STATES, 1861-1879
The Northern inflation coincided almost exactly in its early stages with the inflation in the South, and was produced by the same basic factor - a budgetary deficit due to war expenditure. The financial mobilization of the North was handicapped at the outset by a deficit inherited from the previous administration and by an impaired national credit. The prompt response of the Northern banks enabled the Treasury to overcome this initial handicap and to finance the greatly increased expenditure through the early months of the war. How long orthodox methods of borrowing would have sufficed has been ever since a matter of debate. Toward the end of 1861 the banking system had begun to show signs of serious strain which was greatly aggravated by the policies of Secretary Chase in concentrating at the Treasury a very large share of the supply of specie. The unfavorable state of national finances at the end of the year and the danger of war with England over the Trent affair were enough to produce a panic on December 16 and to force a suspension of specie payments on December 30, 1861
THE EFFECT OF INFLATION ON PRIVATE CONTRACTS: UNITED STATES, 1861-1879
The American Civil War provides ample material for studying the legal consequences of currency depreciation. The sudden demands of war on government budgets made it necessary in both North and South to issue a large volume of paper money, which produced a general rise in prices, a premium on gold, and all the other indices of major monetary inflation. American history had already illustrated the dangers in the use of unstable monetary standards and in too rapid an expansion of the monetary supply. The period of the Civil War is of peculiar interest to lawyers, however, because the record of private litigation is more abundant and because of the different course that inflation took in the two main areas. In the North the depreciation was arrested when the purchasing power of money had been cut to approximately one-half of its pre-war ratio. In the South continued issues of paper money brought progressive depreciation of the currency until its final complete collapse. We have therefore for comparison two great communities, governed by essentially the same legal system, projected side by side through varying degrees of monetary convulsion. From a study of the legal devices employed to meet these emergencies it is possible to derive some conclusions as to the resources of American law in the face of inflation. The limitations on the effectiveness of such devices may also suggest the hazards that face any system of private contract in periods of monetary disturbance
The roots of "Western European societal evolution". A concept of Europe by JenĆ SzƱcs
JenĆ SzƱcs wrote his essay entitled Sketch on the three regions of Europe in the early 1980s in Hungary. During these years, a historically well-argued opinion emphasising a substantial difference between Central European and Eastern European societies was warmly received in various circles of the political opposition. In a wider European perspective SzƱcs used the old âliberty toposâ which claims that the history of Europe is no other than the fulfillment of liberty. In his Sketch, SzƱcs does not only concentrate on questions concerning the Middle Ages in Western Europe. Yet it is this stream of thought which brought a new perspective to explaining European history. His picture of the Middle Ages represents well that there is a way to integrate all typical Western motifs of post-war self-definition into a single theory. Mainly, the âliberty motifâ, as a sign of âEuropeanismâ â in the interpretation of BibĂłâs concept, Anglo-saxon Marxists and Weberâs social theory â, developed from medieval concepts of state and society and from an analysis of economic and social structures. SzƱcsâs historical aspect was a typical intellectual product of the 1980s: this was the time when a few Central European historians started to outline non-Marxist aspects of social theory and categories of modernisation theories, but concealing them with Marxist terminology
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