28,584 research outputs found
When is electromagnetic spectrum fungible?
Fungibility is a common assumption for market-based spectrum management. In this paper, we explore the dimensions of practical fungibility of frequency bands from the point of view of the spectrum buyer who intends to use it. The exploration shows that fungibility is a complex, multidimensional concept that cannot casually be assumed. We develop two ideas for quantifying fungibility-(i) of a fungibility space in which the 'distance' between two slices of spectrum provides score of fungibility and (ii) a probabilistic score of fungibility. © 2012 IEEE
Ratchet effect in dc SQUIDs
We analyzed voltage rectification for dc SQUIDs biased with ac current with
zero mean value. We demonstrate that the reflection symmetry in the
2-dimensional SQUID potential is broken by an applied flux and with appropriate
asymmetries in the dc SQUID. Depending on the type of asymmetry, we obtain a
rocking or a simultaneously rocking and flashing ratchet, the latter showing
multiple sign reversals in the mean voltage with increasing amplitude of the ac
current. Our experimental results are in agreement with numerical solutions of
the Langevin equations for the asymmetric dc SQUID.Comment: 10 pages including 5 Postscript figure
Human complement factor H
We isolated cDNA clones coding for the functionally important tryptic N-terminal38-
kDa fragment of human complement control protein factor H using polyclonal and
monoclonal antibodies to screen a human liver cDNA library cloned in a bacterial
expression vector, PEX-1. By testing the reactivity of antibodies specific for the
recombinant proteins produced by individual clones with proteolytic fragments of
serum H the exact position of these cDNA clones within H was mapped. One clone,
H-19, coding for the 38-kDa fragment of H was sequenced and found to code for 289
amino acids derived from the 38-kDa N-terminal fragment as well as for the first 108
amino acids belonging to the complementary 142-kDa tryptic fragment. The derived
protein sequence could be arranged in 6 highly homologous repeats of about 60 amino
acids each, the homology between the repeats being determined by the characteristic
position of cysteine, proline, glycine, tyrosine and tryptophane residues. The region
coding for the epitope recognized by one of our monoclonal antibodies was localized
by subcloning restriction fragments of H-19 into the expression plasmid and testing
for the expression of this epitope
Non-Markovian master equation for a damped oscillator with time-varying parameters
We derive an exact non-Markovian master equation that generalizes the
previous work [Hu, Paz and Zhang, Phys. Rev. D {\bf 45}, 2843 (1992)] to damped
harmonic oscillators with time-varying parameters. This is achieved by
exploiting the linearity of the system and operator solution in Heisenberg
picture. Our equation governs the non-Markovian quantum dynamics when the
system is modulated by external devices. As an application, we apply our
equation to parity kick decoupling problems. The time-dependent dissipative
coefficients in the master equation are shown to be modified drastically when
the system is driven by pulses. For coherence protection to be effective,
our numerical results indicate that kicking period should be shorter than
memory time of the bath. The effects of using soft pulses in an ohmic bath are
also discussed
Effective potential analysis for 5D SU(2) gauge theories at finite temperature and radius
We calculate the one loop effective potential for a 5D SU(2) gauge field
theory at finite temperature and radius R=1/M. This calculation is
performed, for the first time, in the case of background fields with two
constant components (directed towards the compact extra dimension
with radius R) and (directed towards the compact Euclidean time
with radius ). This model possesses two discrete symmetries known as
Z_{M}(2) and Z_{T}(2). The corresponding phase diagram is presented in Ref. 4.
However the arguments which lead to this diagram are mainly qualitative. We
present a detailed analysis, from our point of view, for this phase diagram,
and we support our arguments performing lattice simulations for a simple
phenomenological model with two scalar fields interacting through the
previously calculated potential.Comment: 18 pages, 7 figures ; typos correcte
Variability in Catheter-Associated Asymptomatic Bacteriuria Rates Among Individual Nurses in Intensive Care Units: An Observational Cross-Sectional Study
Catheter-associated asymptomatic bacteriuria (CAABU) is frequent in intensive care units (ICUs) and contributes to the routine use of antibiotics and to antibiotic-resistant infections. While nurses are responsible for the implementation of CAABU-prevention guidelines, variability in how individual nurses contribute to CAABU-free rates in ICUs has not been previously explored. This study’s objective was to examine the variability in CAABU-free outcomes of individual ICU nurses. This observational cross-sectional study used shift-level nurse-patient data from the electronic health records from two ICUs in a tertiary medical center in the US between July 2015 and June 2016. We included all adult (18+) catheterized patients with no prior CAABU during the hospital encounter and nurses who provided their care. The CAABU-free outcome was defined as a 0/1 indicator identifying shifts where a previously CAABU-free patient remained CAABU-free (absence of a confirmed urine sample) 24–48 hours following end of shift. The analytical approach used Value-Added Modeling and a split-sample design to estimate and validate nurse-level CAABU-free rates while adjusting for patient characteristics, shift, and ICU type. The sample included 94 nurses, 2,150 patients with 256 confirmed CAABU cases, and 21,729 patient shifts. Patients were 55% male, average age was 60 years. CAABU-free rates of individual nurses varied between 94 and 100 per 100 shifts (Wald test: 227.88, P\u3c0.001) and were robust in cross-validation analyses (correlation coefficient: 0.66, P\u3c0.001). Learning and disseminating effective CAABU-avoidance strategies from top-performers throughout the nursing teams could improve quality of care in ICUs
Search For A Permanent Electric Dipole Moment Using Atomic Indium
We propose indium (In) as a possible candidate for observing the permanent
electric dipole moment (EDM) arising from the violations of parity (P) and
time-reversal (T) symmetries. This atom has been laser cooled and therefore the
measurement of its EDM has the potential of improving on the current best EDM
limit for a paramagnetic atom which comes from thallium. We report the results
of our calculations of the EDM enhancement factor due to the electron EDM and
the ratio of the atomic EDM to the electron-nucleus scalar-pseudoscalar (S-PS)
interaction coupling constant in In in the framework of the relativistic
coupled cluster theory. It might be possible to get new limits for the electron
EDM and the S-PS CP violating coupling constant by combining the results of our
calculations with the measured value of the EDM of In when it is available.
These limits could have important implications for the standard model (SM) of
particle physics.Comment: 5 pages, 1 fig, Rapid Communicatio
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