7,662 research outputs found
Muon Detection of TeV Gamma Rays from Gamma Ray Bursts
Because of the limited size of the satellite-borne instruments, it has not
been possible to observe the flux of gamma ray bursts (GRB) beyond GeV energy.
We here show that it is possible to detect the GRB radiation of TeV energy and
above, by detecting the muon secondaries produced when the gamma rays shower in
the Earth's atmosphere. Observation is made possible by the recent
commissioning of underground detectors (AMANDA, the Lake Baikal detector and
MILAGRO) which combine a low muon threshold of a few hundred GeV or less, with
a large effective area of 10^3 m^2 or more. Observations will not only provide
new insights in the origin and characteristics of GRB, they also provide
quantitative information on the diffuse infrared background.Comment: Revtex, 12 pages, 3 postscript figures, uses epsfig.st
FTMP (Fault Tolerant Multiprocessor) programmer's manual
The Fault Tolerant Multiprocessor (FTMP) computer system was constructed using the Rockwell/Collins CAPS-6 processor. It is installed in the Avionics Integration Research Laboratory (AIRLAB) of NASA Langley Research Center. It is hosted by AIRLAB's System 10, a VAX 11/750, for the loading of programs and experimentation. The FTMP support software includes a cross compiler for a high level language called Automated Engineering Design (AED) System, an assembler for the CAPS-6 processor assembly language, and a linker. Access to this support software is through an automated remote access facility on the VAX which relieves the user of the burden of learning how to use the IBM 4381. This manual is a compilation of information about the FTMP support environment. It explains the FTMP software and support environment along many of the finer points of running programs on FTMP. This will be helpful to the researcher trying to run an experiment on FTMP and even to the person probing FTMP with fault injections. Much of the information in this manual can be found in other sources; we are only attempting to bring together the basic points in a single source. If the reader should need points clarified, there is a list of support documentation in the back of this manual
The good, the bad and the ugly .... of Horava gravity
I review the good, the bad and the ugly of the non-projectable versions of
Horava gravity. I explain how this non-relativistic theory was constructed and
why it was touted with such excitement as a quantum theory of gravity. I then
review some of the issues facing the theory, explaining how strong coupling
occurs and why this is such a problem for both phenomenology and the question
of renormalisability. Finally I comment on possible violations of Equivalence
Principle, and explain why these could be an issue for Blas et al's "healthy
extension". This paper was presented as a talk at PASCOS 2010 in Valencia.Comment: 7 page
Development and psychometric assessment of the basic resuscitation skills self-efficacy scale
Background: Nurses are usually the first responders to an in-hospital cardiac arrest. As bystanders, nurses are expected to master some basic resuscitation skills. Self-efficacy levels are a key component in the acquisition of basic resuscitation skills.
Aim: To develop, test and validate a self-efficacy scale that accurately measures nursing students’ confidence levels in their capabilities when responding to a cardiac arrest.
Methods: This study enrolled a conveniently recruited sample of 768 nursing students from two different universities in Europe. The Basic Resuscitation Skills Self-Efficacy Scale (BRS-SES) was developed and its psychometrics established. Content validity, criterion validity, discriminant validity, and internal consistency were assessed. Performing item-analysis, principal component analysis and known group analysis evaluated construct validity.
Results: Principal component analysis revealed the three-subscale structure of the final 18-item BRS-SES. A Cronbach’s alpha of 0.96 for the overall measure demonstrated the internal consistency of the BRS-SES. Data also evidenced discriminant ability of the BRS-SES and known-group analysis showed its high sensitivity and specificity.
Conclusion: The BRS-SES showed good psychometric properties for measuring self-efficacy in basic resuscitation skills that nursing students, as future first responders to an in-hospital cardiac arrest, will be expected to master.
Implications for practice: The BRS-SES is a validated tool that could have a positive impact on the training of basic resuscitation skills and, therefore, on patients’ outcomes
Galaxy Clusters in the Line of Sight to Background Quasars: I. Survey Design and Incidence of MgII Absorbers at Cluster Redshifts
We describe the first optical survey of absorption systems associated with
galaxy clusters at z= 0.3-0.9. We have cross-correlated SDSS DR3 quasars with
high-redshift cluster/group candidates from the Red-Sequence Cluster Survey. We
have found 442 quasar-cluster pairs for which the MgII doublet might be
detected at a transverse (physical) distance d<2 Mpc from the cluster centers.
To investigate the incidence (dN/dz) and equivalent-width distribution n(W) of
MgII systems at cluster redshifts, two statistical samples were drawn out of
these pairs: one made of high-resolution spectroscopic quasar observations (46
pairs), and one made of quasars used in MgII searches found in the literature
(375 pairs). The results are: (1) the population of strong MgII systems
(W_0>2.0 Ang.) near cluster redshifts shows a significant (>3 sigma)
overabundance (up to a factor of 15) when compared with the 'field' population;
(2) the overabundance is more evident at smaller distances (d<1 Mpc) than
larger distances (d<2 Mpc) from the cluster center; and, (3) the population of
weak MgII systems (W_0<0.3 Ang.) near cluster redshifts conform to the field
statistics. Unlike in the field, this dichotomy makes n(W) in clusters appear
flat and well fitted by a power-law in the entire W-range. A sub-sample of the
most massive clusters yields a stronger and still significant signal. Since
either the absorber number density or filling-factor/cross-section affects the
absorber statistics, an interesting possibility is that we have detected the
signature of truncated halos due to environmental effects. Thus, we argue that
the excess of strong systems is due to a population of absorbers in an
overdense galaxy environment, and the lack of weak systems to a different
population, that got destroyed in the cluster environment. (Abridged)Comment: Accepted for publication in the Astrophysical Journa
QCD
We discuss QCD studies that will be possible at LEP2. We examine both
experimental and theoretical aspects of jets, fragmentation functions,
multiplicities and particle spectra.Comment: 44 pages, Latex, epsfig, 18 figures, to appear on the Report of the
Workshop on Physics at LEP2, CERN 96-01, vol. 1, 199
- …