2,468 research outputs found
The SoLid anti-neutrino detector's readout system
The SoLid collaboration have developed an intelligent readout system to
reduce their 3200 silicon photomultiplier detector's data rate by a factor of
10000 whilst maintaining high efficiency for storing data from anti-neutrino
interactions. The system employs an FPGA-level waveform characterisation to
trigger on neutron signals. Following a trigger, data from a space time region
of interest around the neutron will be read out using the IPbus protocol. In
these proceedings the design of the readout system is explained and results
showing the performance of a prototype version of the system are presented
Relations between Kauffman and Homfly satellite invariants
We extend a mod 2 relation between the Kauffman and Homfly polynomials, first
observed by Rudolph in 1987, to the general Kauffman and Homfly satellite
invariants.Comment: 9 page
Assessing with e-Ase
The Educational Development Unit have produced a guide to assist academic staff in transforming assessment practices underpinned by technology. 'Assessing with e-Ase' highlights how technology combined with sound pedagogy has the potential to enhance the student experience of learning, teaching and assessment.
Drawing on the experiences, knowledge and understanding of the e-assessment project at Middlesex University, it offers a consideration of contextual, procedural and logistical factors that may impact when using e-assessment practices. Key issues for consideration when developing and implementing e-assessment are included along with the part played by policy and strategy. Examples of departmental case studies, an outline of the support available to staff and links to resources that may provide useful additional information are also included
Quantum gravitational optics: the induced phase
The geometrical approximation of the extended Maxwell equation in curved
spacetime incorporating interactions induced by the vacuum polarization effects
is considered. Taking into account these QED interactions and employing the
analogy between eikonal equation in geometrical optics and Hamilton-Jacobi
equation for the particle motion, we study the phase structure of the modified
theory. There is a complicated, local induced phase which is believed to be
responsible for the modification of the classical picture of light ray. The
main features of QGO could be obtained through the study of this induced phase.
We discuss initial principles in conventional and modified geometrical optics
and compare the results.Comment: 10 pages, REVTex forma
Vacuum Fluctuations of a massless spin-1/2 field around multiple cosmic strings
We study the interaction of a massless quantized spinor field with the
gravitational filed of N parallel static cosmic strings by using a perturbative
approach. We show that the presence of more than one cosmic string gives rise
to an additional contribution to the energy density of vacuum fluctuations,
thereby leading to a vacuum force attraction between two parallel cosmic
strings.Comment: Class. Quantum Grav. 14(1997) 321
BATSE Gamma-Ray Burst Line Search: IV. Line Candidates from the Visual Search
We evaluate the significance of the line candidates identified by a visual
search of burst spectra from BATSE's Spectroscopy Detectors. None of the
candidates satisfy our detection criteria: an F-test probability less than
10^-4 for a feature in one detector and consistency among the detectors which
viewed the burst. Most of the candidates are not very significant, and are
likely to be fluctuations. Because of the expectation of finding absorption
lines, the search was biased towards absorption features. We do not have a
quantitative measure of the completeness of the search which would enable a
comparison with previous missions. Therefore a more objective computerized
search has begun.Comment: 18 pages AASTEX 4.0; 4 POSTSCRIPT figures on request from
[email protected]
Gallus GBrowse: a unified genomic database for the chicken
Gallus GBrowse (http://birdbase.net/cgi-bin/gbrowse/gallus/) provides online access to genomic and other information about the chicken, Gallus gallus. The information provided by this resource includes predicted genes and Gene Ontology (GO) terms, links to Gallus In Situ Hybridization Analysis (GEISHA), Unigene and Reactome, the genomic positions of chicken genetic markers, SNPs and microarray probes, and mappings from turkey, condor and zebra finch DNA and EST sequences to the chicken genome. We also provide a BLAT server (http://birdbase.net/cgi-bin/webBlat) for matching user-provided sequences to the chicken genome. These tools make the Gallus GBrowse server a valuable resource for researchers seeking genomic information regarding the chicken and other avian species
Symmetry Factors of Feynman Diagrams for Scalar Fields
The symmetry factor of Feynman diagrams for real and complex scalar fields is
presented. Being analysis of Wick expansion for Green functions, the mentioned
factor is derived in a general form. The symmetry factor can be separated into
two ones corresponding to that of connected and vacuum diagrams. The
determination of symmetry factors for the vacuum diagrams is necessary as they
play a role in the effective action and phase transitions in cosmology. In the
complex scalar theory the diagrams different in topology may give the same
contribution, hence inverse of the symmetry factor (1/S) for total contribution
is a summation of each similar ones (1/S_i), i.e., 1/S = \sum_i (1/S_i).Comment: Journal version, new references adde
Labels for non-individuals
Quasi-set theory is a first order theory without identity, which allows us to
cope with non-individuals in a sense. A weaker equivalence relation called
``indistinguishability'' is an extension of identity in the sense that if
is identical to then and are indistinguishable, although the
reciprocal is not always valid. The interesting point is that quasi-set theory
provides us a useful mathematical background for dealing with collections of
indistinguishable elementary quantum particles. In the present paper, however,
we show that even in quasi-set theory it is possible to label objects that are
considered as non-individuals. We intend to prove that individuality has
nothing to do with any labelling process at all, as suggested by some authors.
We discuss the physical interpretation of our results.Comment: 11 pages, no figure
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