197 research outputs found
Evaluation of Giga-bit Ethernet Instrumentation for SalSA Electronics Readout (GEISER)
An instrumentation prototype for acquiring high-speed transient data from an
array of high bandwidth antennas is presented. Multi-kilometer cable runs
complicate acquisition of such large bandwidth radio signals from an extensive
antenna array. Solutions using analog fiber optic links are being explored,
though are very expensive. We propose an inexpensive solution that allows for
individual operation of each antenna element, operating at potentially high
local self-trigger rates. Digitized data packets are transmitted to the surface
via commercially available Giga-bit Ethernet hardware. Events are then
reconstructed on a computer farm by sorting the received packets using standard
networking gear, eliminating the need for custom, very high-speed trigger
hardware. Such a system is completely scalable and leverages the hugh capital
investment made by the telecommunications industry. Test results from a
demonstration prototype are presented.Comment: 8 pages, to be submitted to NIM
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The most problematic symptoms of prion disease - an analysis of carer experiences
Objectives:
Prion diseases are rare dementias that most commonly occur sporadically, but can be inherited or acquired, and for which there is no cure. We sought to understand which prion disease symptoms are most problematic for carers, to inform the development of outcome measures.
Design:
Self-completed questionnaire with follow-up of a subset of participants by structured interview.
Setting:
A nested study in the UK National Prion Monitoring Cohort, a longitudinal observational study.
Participants and measurements:
71 carers, of people with different prion diseases with a wide range of disease severity, identified 236 of their four most problematic symptoms by questionnaire which were grouped into ten domains. Structured interviews were then done to qualitatively explore these experiences. Eleven family carers of people with prion disease were selected, including those representative of a range of demographics and disease subtypes and those who cared for people with prion disease, living or recently deceased. Interviews were transcribed and formally studied.
Results:
The six most problematic symptom domains were: mobility and coordination; mood and behavior; personal care and continence; eating and swallowing; communication; and cognition and memory. The prevalence of these symptoms varied significantly by disease stage and type. A formal analysis of structured interviews to explore these domains is reported.
Conclusions:
We make suggestions about how healthcare professionals can focus their support for people with prion disease. Clinical trials that aim to generate evidence regarding therapies that might confer meaningful benefits to carers should consider including outcome measures that monitor the symptomatic domains we have identified as problematic
Antiquark nuggets as dark matter: New constraints and detection prospects
Current evidence for dark matter in the universe does not exclude heavy
composite nuclear-density objects consisting of bound quarks or antiquarks over
a significant range of masses. Here we analyze one such proposed scenario,
which hypothesizes antiquark nuggets with a range of log10(B) = 24-30 with
specific predictions for spectral emissivity via interactions with normal
matter. We find that, if these objects make up the majority of the dark matter
density in the solar neighborhood, their radiation efficiency in solids is
marginally constrained, due to limits from the total geothermal energy budget
of the Earth. At allowed radiation efficiencies, the number density of such
objects can be constrained to be well below dark matter densities by existing
radio data over a mass range currently not restricted by other methods.Comment: 6 pages, 3 figures, revised references; submitted to PR
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