32,265 research outputs found
High Energy Colliders
We consider the high energy advantages, disadvantages and luminosity
requirements of hadrons, leptons and photon-photon colliders. Technical
problems in obtaining increased energy in each type of machine are presented.
The machines relative size are also discussed.Comment: LaTeX, 27 pages, 8 figures (eps, ps). Submitted to the Proceedings of
the Princeton's 250th Anniversary Conference on Critical Problems in Physic
High Luminosity Muon Collider Design
Muon Colliders have unique technical and physics advantages and disadvantages
when compared with both hadrons and electron machines. They should be regarded
as complementary. Parameters are given of a 4 TeV high luminosity muon-muon
collider, and of a 0.5 TeV demonstration machine. We discuss the various
systems in such muon collider.Comment: LaTeX 5 pages 4 figure
Future Colliders
The high energy physics advantages, disadvantages and luminosity requirements
of hadrons, of leptons and photon-photon colliders are considered. Technical
arguments for increased energy in each type of machine are presented. Their
relative size, and the implications of size on cost are discussed.Comment: LaTeX, 10 pages, 10figure
MONTE CARLO SIMULATIONS OF MUON PRODUCTION
Muon production requirements for a muon collider are presented. Production of
muons from pion decay is studied. Lithium lenses and solenoids are considered
for focussing pions from a target, and for matching the pions into a decay
channel. Pion decay channels of alternating quadrupoles and long solenoids are
compared. Monte Carlo simulations are presented for production of by protons over a wide energy range, and criteria for
choosing the best proton energy are discussed.Comment: Latex uses mu95.sty, 19 pages, 5 postscript figures. A postscript
file can be seen at URL http://www.cap.bnl.gov/~cap/mumu/important.html
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Strong spectral evolution during the prompt emission of GRB 070616
Swift has revealed features in GRB early light curves, such as steep decays
and X-ray flares, whose properties are consistent with an internal origin
though they are far from understood. The steep X-ray decay is often explained
using the curvature effect; however a significant number of GRBs display strong
spectral evolution during this phase, and a new mechanism must be invoked to
explain this. Of particular interest are the longest duration GRBs in which the
early emission can be studied in most detail. Here we present data for GRB
070616, in which the prompt emission shows a complex multipeaked structure,
leading to one of the longest prompt emission durations ever recorded. We take
advantage of extensive coverage of such a long burst by all Swift instruments.
Combining data from Swift and Suzaku we study the evolution of the prompt
emission spectrum, following the temporal variability of the peak energy and
spectral slope.Comment: 4 pages, 2 figures (Fig 1 in colour), contributed talk, submitted to
the proceedings of Gamma Ray Bursts 2007, Santa Fe, New Mexico, November 5-9
200
Challenges for South African anthropology in the 3rd Millennium
Towards the end of one’s career, there’s a powerful inclination to look backwards instead of forwards. You become more interested in histories, biographies and obituaries; you reflect on your own life and career. It’s not inevitable, and it can be resisted. Marshall McLuhan was well into his 50s – an obscure Canadian Eng Lit academic – when he had his vision of the nature and future of the media and anticipated a ‘global village’ that the Internet has turned into a reality since his death in 1980 (McLuhan and Powers 1989) – but more on that in due course. Cui Bono? At first I gave into the tendency to look back. Initially, for this lecture, I thought to analyse my own career in South Africa in terms of who benefited most from it: South African anthropology and my students … or me. I would call the lecture ‘Cui Bono?’ But then I realised, with Latin tags on the way out, younger colleagues and students in the audience might think I was referring to a traditional Australian greeting (Coo-ee) and an Irish philanthropist pop singer (Bono). The title would be totally mystifying to many until I explained that it meant ‘to whom the good’ – in other words, who benefits? But there were other objections to this project besides the title. Even the most postmodern of reflexive anthropologists would balk at making such a self-assessment – it was not for me to judge. Anyway, I already knew the answer: My career in South Africa has not been impeded by political harassments, imprisonment or conscription. I did make some small negligible contributions to the ‘struggle’ through writing or drawing, and I did some community service, on campus or off in the same way. At a critical stage I assisted with the process that eventually produced a national staff association, now called NTESU. The only price I have paid for these distractions from serious publishing at a critical stage of my career was deservedly slow promotion. I continue to contribute to the community mainly through membership of the older of Grahamstown’s two very active Rotary clubs. It’s all I have time for, but nothing to boast about. In sum, I’ve enjoyed what my long-term colleague and Grahamstown’s Citizen of the Year (another Rotary initiative) Michael Whisson likes to call ‘sheltered employment’ – his typically ironic way of reminding us of how privileged we academics are, doing what we enjoy, in pleasant surroundings, among intelligent colleagues and the cream of our youth, with plenty of flexi-time and opportunities for subsidized travel. And now I have benefited again by being promoted to full professor without sufficiently earning my keep through subsidies on academic outputs. Whatever I might have given back through teaching and administration the net is in my favour, and I am grateful beyond words
Amplified Dispersive Fourier-Transform Imaging for Ultrafast Displacement Sensing and Barcode Reading
Dispersive Fourier transformation is a powerful technique in which the
spectrum of an optical pulse is mapped into a time-domain waveform using
chromatic dispersion. It replaces a diffraction grating and detector array with
a dispersive fiber and single photodetector. This simplifies the system and,
more importantly, enables fast real-time measurements. Here we describe a novel
ultrafast barcode reader and displacement sensor that employs
internally-amplified dispersive Fourier transformation. This technique
amplifies and simultaneously maps the spectrally encoded barcode into a
temporal waveform. It achieves a record acquisition speed of 25 MHz -- four
orders of magnitude faster than the current state-of-the-art.Comment: Submitted to a journa
Research Notes : United States : A possible interaction between cyt-Y3 and y20-k2
Interactions of organelle genomes are a well-documented fact. Interac-tion can take the form of metabolite and energy exchange, co-production of enzyme subunits, and co-production of membrane structural and organizational components (Wallace, 1982). Nucleo-cytoplasmic interaction also has been documented for various traits affecting vegetative and harvest indices (Rob-ertson and Frey, 1984), cytoplasmic male sterility (Levings, 1983), and other agronomic characters (Harvey et al., 1972; Kihara, 1982)
Research Notes : United States : Summary of locus-to-locus linkage data in soybean
Summary of locus-to-locus linkage data in soybea
A knowledge-based approach to configuration layout, justification, and documentation
The design, development, and implementation is described of a prototype expert system which could aid designers and system engineers in the placement of racks aboard modules on Space Station Freedom. This type of problem is relevant to any program with multiple constraints and requirements demanding solutions which minimize usage of limited resources. This process is generally performed by a single, highly experienced engineer who integrates all the diverse mission requirements and limitations, and develops an overall technical solution which meets program and system requirements with minimal cost, weight, volume, power, etc. This system architect performs an intellectual integration process in which the underlying design rationale is often not fully documented. This is a situation which lends itself to an expert system solution for enhanced consistency, thoroughness, documentation, and change assessment capabilities
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