6,951 research outputs found
Design of testbed and emulation tools
The research summarized was concerned with the design of testbed and emulation tools suitable to assist in projecting, with reasonable accuracy, the expected performance of highly concurrent computing systems on large, complete applications. Such testbed and emulation tools are intended for the eventual use of those exploring new concurrent system architectures and organizations, either as users or as designers of such systems. While a range of alternatives was considered, a software based set of hierarchical tools was chosen to provide maximum flexibility, to ease in moving to new computers as technology improves and to take advantage of the inherent reliability and availability of commercially available computing systems
Empirical evidence for the Birch and Swinnerton-Dyer conjectures for modular jacobians of genus 2 curves
This paper provides empirical evidence for the Birch and Swinnerton-Dyer conjectures for modular Jacobians of genus 2 curves. The second of these conjectures relates six quantities associated to a Jacobian over the rational numbers. One of these six quantities is the size of the Shafarevich-Tate group. Unable to compute that, we computed the five other quantities and solved for the last one. In all 32 cases, the result is very close to an integer that is a power of 2. In addition, this power of 2 agrees with the size of the 2-torsion of the Shafarevich-Tate group, which we could compute
A dynamical and kinematical model of the Galactic stellar halo and possible implications for galaxy formation scenarios
We re-analyse the kinematics of the system of blue horizontal branch field
(BHBF) stars in the Galactic halo (in particular the outer halo), fitting the
kinematics with the model of radial and tangential velocity dispersions in the
halo as a function of galactocentric distance r proposed by Sommer-Larsen,
Flynn & Christensen (1994), using a much larger sample (almost 700) of BHBF
stars. The basic result is that the character of the stellar halo velocity
ellipsoid changes markedly from radial anisotropy at the sun to tangential
anisotropy in the outer parts of the Galactic halo (r greater than approx 20
kpc). Specifically, the radial component of the stellar halo's velocity
ellipsoid decreases fairly rapidly beyond the solar circle, from approx 140 +/-
10 km/s at the sun, to an asymptotic value of 89 +/- 19 km/s at large r. The
rapid decrease in the radial velocity dispersion is matched by an increase in
the tangential velocity dispersion, with increasing r.
Our results may indicate that the Galaxy formed hierarchically (partly or
fully) through merging of smaller subsystems - the 'bottom-up' galaxy formation
scenario, which for quite a while has been favoured by most theorists and
recently also has been given some observational credibility by HST observations
of a potential group of small galaxies, at high redshift, possibly in the
process of merging to a larger galaxy (Pascarelle et al 1996).Comment: Latex, 16 pages. 2 postscript figures. Submitted to the Astrophysical
Journal. also available at http://astro.utu.fi/~cflynn/outerhalo.htm
Legal Reasoning and the Jurisprudence of Vertical Restraints: The Limitations of Neoclassical Economic Analysis in the Resolution of Antitrust Disputes
Cognizant of historical shifts in the methodology and standards applied in antitrust analysis, particularly in the analysis of vertical restraints, this Article first considers the underlying jurisprudential nature of legal reasoning as background for determining what the law of vertical restraints ought to be. The Article then explores the implications of substitution economic analysis --in the narrow sense of the economic analysis advocated by the Chicago School of law and economics --for legal reasoning in disputes arising under the antitrust laws. A more accurate, multivalued background for antitrust policy is explored. This Article finally proposes a method for analysis of vertical restraints that will allow antitrust law to implement the goals Congress has mandated, yet address constructively the commercial practices it must regulate
Molecular Characterisation of Bacteriophage K Towards Applications for the Biocontrol of Pathogenic Staphylococci
End of project reportThe aim of this work was to characterise staphylococcal bacteriophage (a bacterial virus) and to assess their potential as therapeutic agents against pathogenic strains of Staphylococcus aureus, particularly mastitis-causing strains. The project included the use of two newly isolated phage CS1 and DW2, and an existing polyvalent phage. The new phage were isolated from the farmyard and characterised by electron microscopy and restriction analysis. Both phage were shown to belong to the Siphoviridae family and were lytic for representatives of all three clonal groups of Irish mastitis-associated staphylococci. A cocktail of three phage (CS1, DW2 and K) at 108 (plaque forming units) PFU/ml was infused into cows teats in animal trials. The lack of an increase in somatic cell counts in milks indicated strongly that the phage did not irritate the animal. In addition, the most potent phage used in this study, phage K, was further studied by genome sequencing, which revealed a linear DNA genome of 127,395 base pairs, which encodes 118 putative ORFs (open reading frames)
A New Method for Obtaining Binary Pulsar Distances and its Implications for Tests of General Relativity
We demonstrate how measuring orbital period derivatives can lead to more
accurate distance estimates and transverse velocities for some nearby binary
pulsars. In many cases this method will estimate distances more accurately than
is possible by annual parallax, as the relative error decreases as t^-5/2.
Unfortunately, distance uncertainties limit the degree to which nearby
relativistic binary pulsars can be used for testing the general relativistic
prediction of orbital period decay to a few percent. Nevertheless, the measured
orbital period derivative of PSR B1534+12 agrees within the observational
uncertainties with that predicted by general relativity if the proper-motion
contribution is accounted for.Comment: 4 pages, latex, uuencoded compressed postscript + source, no figures,
uses aaspptwo.sty and dec.sty, accepted for publication in ApJL, omitted
reference now include
Analyzing the Impact of Changes in Trade and Domestic Policies: The Case of the Soybean Complex
This study analyzes the impacts of domestic and trade policy changes on the soybean complex using a Stochastic Equilibrium Displacement Model (SEDM). Three different policies, Loan Deficiency Payments (LDP), transportation costs and export taxes are considered in the analysis. The results indicate that Brazil benefits from a reduction in transportation costs and becomes more competitive in the global soybean market. Brazilian exports of soybeans increase due to relatively lower export prices. However, Brazil gains little improvement in the export competitiveness of the soybean joint products, soybean meal and oil. A lower U.S. LDP rate results in the loss of competitiveness for the United States in the world soybean market. Furthermore, the results show that an Argentine export tax reduction increases soybean exports from Argentina, but it reduces the global supply of soybean meal and soybean oil.International Trade, Loan Deficiency Payment, Soybean, Soybean Joint Products, Stochastic Equilibrium Displacement Model, Transportation Costs, Agricultural and Food Policy, International Relations/Trade,
Half-life of the electron-capture decay of 97Ru: Precision measurement shows no temperature dependence
We have measured the half-life of the electron-capture (ec) decay of 97Ru in
a metallic environment, both at low temperature (19K), and also at room
temperature. We find the half-lives at both temperatures to be the same within
0.1%. This demonstrates that a recent claim that the ec decay half-life for 7Be
changes by $0.9% +/- 0.2% under similar circumstances certainly cannot be
generalized to other ec decays. Our results for the half-life of 97Ru,
2.8370(14)d at room temperature and 2.8382(14)d at 19K, are consistent with,
but much more precise than, previous room-temperature measurements. In
addition, we have also measured the half-lives of the beta-emitters 103Ru and
105Rh at both temperatures, and found them also to be unchanged.Comment: 6 pages, 6 figure
Becoming an accredited medical teacher in the UK
Teaching and training are integral to the different, core roles of a trainee. Therefore, there is a shift in the medical profession towards credentialing teaching and training skills. Postgraduate qualifications in medical education are likely to be more important for professional development. In recent years, the number of medical education awards and training programmes has increased rapidly. This pluralism, however, may become a source of confusion for those considering enrolment on such programmes. This article summarises the nomenclature, awarding bodies, levels of qualification, programmes and positions available for those wishing to advance their educational practice. The article will focus on opportunities available to UK-based doctors and particularly for doctors in training
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