57,039 research outputs found
Glasgow time signals
From 1859 to 1864, both visual and audio one o’clock time signals operated in Glasgow. Although the University carried a remit to provide the city’s time, following convoluted processes of establishment, a local chronometer-maker operated a time ball for 4 years. Towards the end of the period, time guns were triggered by telegraph from the Royal Observatory Edinburgh. Both exercises caused aggravation for the University. For the ball, the Professor of Astronomy, John Pringle Nichol, failed to convince the City Council that the “drop” control should originate from the University’s Observatory. For the guns, Robert Grant, the newly appointed Astronomy Chair holder, was aggrieved by the Astronomer Royal for Scotland, Piazzi Smyth, appearing to operate above his station. Rather than having only a once per day reference, both projects were abandoned as the University laid a dedicated telegraph cable from its observatory to control many public clocks and additional clocks with large sweep fingers indicating exact time to the second
Causation and melanoma classification
In this article, I begin by giving a brief history of melanoma causation. I then discuss the
current manner in which malignant melanoma is classified. In general, these systems of
classification do not take account of the manner of tumour causation. Instead, they are based
on phenomenological features of the tumour, such as size, spread, and morphology. I go on to
suggest that misclassification of melanoma is a major problem in clinical practice. I therefore
outline an alternative means of classifying these tumours based on causal factors. By analogy
with similar systems that have recently emerged for other cancers, I suggest that this causal
classification is likely to be both workable and helpful, even in the absence of a full causalmechanistic
understanding of the aetiology of the tumour
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Addressing School Dropout in Texas: A Summary for Administrators and Policymakers of "Dropout Prevention: A Practice Guide"
This booklet summarizes the information from: Dropout Prevention: A Practice Guide, available on the Institute of Education Sciences web site at http://ies.ed.gov/ncee/wwc.Educatio
The controllable pi - SQUID
We have fabricated and studied a new kind of DC SQUID in which the magnitude
and sign of the critical current of the individual Josephson junctions can be
controlled by additional voltage probes connected to the junctions. We show
that the amplitude of the voltage oscillations of the SQUID as a function of
the applied magnetic field can be tuned and that the phase of the oscillations
can be switched between 0 and in the temperature range of 0.1 - 4.2 K
using a suitable control voltage. This is equivalent to the external
application of (n+1/2) flux quantum.Comment: 3 Figures, submitted to Applied Physics Letter
Clonal analysis of meningococci during a 26 year period prior to the introduction of meningococcal serogroup C vaccines
Meningococcal disease remains a public health burden in the UK and elsewhere. Invasive Neisseria meningitidis, isolated in Scotland between 1972 and 1998, were characterised retrospectively to examine the serogroup and clonal structure of the circulating population. 2607 isolates causing invasive disease were available for serogroup and MLST analysis whilst 2517 were available for multilocus sequence typing (MLST) analysis only. Serogroup distribution changed from year to year but serogroups B and C were dominant throughout. Serogroup B was dominant throughout the 1970s and early 1980s until serogroup C became dominant during the mid-1980s. The increase in serogroup C was not associated with one particular sequence type (ST) but was associated with a number of STs, including ST-8, ST-11, ST-206 and ST-334. This is in contrast to the increase in serogroup C disease seen in the 1990s that was due to expansion of the ST-11 clonal complex. While there was considerable diversity among the isolates (309 different STs among the 2607 isolates), a large proportion of isolates (59.9%) were associated with only 10 STs. These data highlight meningococcal diversity over time and the need for ongoing surveillance during the introduction of new meningococcal vaccines
Wireworm Control using Fodder Rape and Mustard – evaluating the use of brassica green manures for the control of wireworm (Agriotes spp.) in organic crops
In a field experiment at ADAS Pwllpeiran in 2001, brassica green manures were grown for 6 weeks and dug in before planting King Edward potatoes, to see if they suppressed wireworm in the crop. There was a trend for potatoes grown after mustard to suffer less damage from both wireworms and slugs than potatoes grown after fodder rape or no green manure, but the differences were not significant. Further trials, with longer green manuring periods, are needed to establish if there is a benefit, and whether the breakdown products of brassica green manures are toxic to wireworms
AZEuS: An Adaptive Zone Eulerian Scheme for Computational MHD
A new adaptive mesh refinement (AMR) version of the ZEUS-3D astrophysical
magnetohydrodynamical (MHD) fluid code, AZEuS, is described. The AMR module in
AZEuS has been completely adapted to the staggered mesh that characterises the
ZEUS family of codes, on which scalar quantities are zone-centred and vector
components are face-centred. In addition, for applications using static grids,
it is necessary to use higher-order interpolations for prolongation to minimise
the errors caused by waves crossing from a grid of one resolution to another.
Finally, solutions to test problems in 1-, 2-, and 3-dimensions in both
Cartesian and spherical coordinates are presented.Comment: 52 pages, 17 figures; Accepted for publication in ApJ
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