2,208 research outputs found
The Fermi surface of CeCoIn5: dHvA
Measurements of the de Haas - van Alphen effect in the normal state of the
heavy Fermion superconductor CeCoIn5 have been carried out using a torque
cantilever at temperatures ranging from 20 to 500 mK and in fields up to 18
tesla. Angular dependent measurements of the extremal Fermi surface areas
reveal a more extreme two dimensional sheet than is found in either CeRhIn5 or
CeIrIn5. The effective masses of the measured frequencies range from 9 to 20
m*/m0.Comment: 4 pages, 2 figures, submitted to PRB Rapid
The important role for intravenous iron in perioperative patient blood management in major abdominal surgery: a randomized controlled trial
Objective: To determine if preoperative intravenous (IV) iron improves outcomes in abdominal surgery patients. Summary Background Data: Preoperative iron deficiency anemia (IDA) occurs frequently; however if left untreated, increases the risk of blood transfusion allogeneic blood transfusion (ABT). Limited evidence supports IDA treatment with preoperative IV iron. This randomized controlled trial aimed to determine whether perioperative IV iron reduced the need for ABT. Methods: Between August 2011 and November 2014, 72 patients with IDA were assigned to receive either IV iron or usual care. The primary endpoint was incidence of ABT. Secondary endpoints were various hemoglobin (Hb) levels, change in Hb between time points, length of stay, iron status, morbidity, mortality, and quality of life 4 weeks postsurgery. Results: A 60% reduction in ABT was observed in the IV iron group compared with the usual care group (31.25% vs 12.5%). Hb values, although similar at randomization, improved by 0.8 g/dL with IV iron compared with 0.1 g/dL with usual care (P = 0.01) by the day of admission. The IV iron group had higher Hb 4 weeks after discharge compared with the usual care group (1.9 vs 0.9 g/dL, P = 0.01), and a shorter length of stay (7.0 vs 9.7 d, P = 0.026). There was no difference in discharge Hb levels, morbidity, mortality, or quality of life. Conclusions: Administration of perioperative IV iron reduces the need for blood transfusion, and is associated with a shorter hospital stay, enhanced restoration of iron stores, and a higher mean Hb concentration 4 weeks after surgery.Bernd Froessler, Peter Palm, Ingo Weber, Nicolette A. Hodyl, Rajvinder Singh and Elizabeth M. Murph
Velocity-selective direct frequency-comb spectroscopy of atomic vapors
We present an experimental and theoretical investigation of two-photon direct
frequency-comb spectroscopy performed through velocity-selective excitation. In
particular, we explore the effect of repetition rate on the
two-photon transitions
excited in a rubidium atomic vapor cell. The transitions occur via step-wise
excitation through the states by use of the direct
output of an optical frequency comb. Experiments were performed with two
different frequency combs, one with a repetition rate of MHz and
one with a repetition rate of MHz. The experimental spectra are
compared to each other and to a theoretical model.Comment: 10 pages, 7 figure
Unusual metamagnetism in CeIrIn
We report a high field investigation (up to 45 T) of the metamagnetic
transition in CeIrIn with resistivity and de-Haas-van-Alphen (dHvA) effect
measurements in the temperature range 0.03-1 K. As the magnetic field is
increased the resistivity increases, reaches a maximum at the metamagnetic
critical field, and falls precipitously for fields just above the transition,
while the amplitude of all measurable dHvA frequencies are significantly
attenuated near the metamagnetic critical field. However, the dHvA frequencies
and cyclotron masses are not substantially altered by the transition. In the
low field state, the resistivity is observed to increase toward low
temperatures in a singular fashion, a behavior that is rapidly suppressed above
the transition. Instead, in the high field state, the resistivity monotonically
increases with temperature with a dependence that is more singular than the
iconic Fermi-liquid, temperature-squared, behavior. Both the damping of the
dHvA amplitudes and the increased resistivity near the metamagnetic critical
field indicate an increased scattering rate for charge carriers consistent with
critical fluctuation scattering in proximity to a phase transition. The dHvA
amplitudes do not uniformly recover above the critical field, with some
hole-like orbits being entirely suppressed at high fields. These changes, taken
as a whole, suggest that the metamagnetic transition in CeIrIn is
associated with the polarization and localization of the heaviest of
quasiparticles on the hole-like Fermi surface.Comment: 29 pages, 9 figure
Thresholds in layered neural networks with variable activity
The inclusion of a threshold in the dynamics of layered neural networks with
variable activity is studied at arbitrary temperature. In particular, the
effects on the retrieval quality of a self-controlled threshold obtained by
forcing the neural activity to stay equal to the activity of the stored paterns
during the whole retrieval process, are compared with those of a threshold
chosen externally for every loading and every temperature through optimisation
of the mutual information content of the network. Numerical results, mostly
concerning low activity networks are discussed.Comment: 15 pages, Latex2e, 6 eps figure
A ferrofluid based neural network: design of an analogue associative memory
We analyse an associative memory based on a ferrofluid, consisting of a
system of magnetic nano-particles suspended in a carrier fluid of variable
viscosity subject to patterns of magnetic fields from an array of input and
output magnetic pads. The association relies on forming patterns in the
ferrofluid during a trainingdphase, in which the magnetic dipoles are free to
move and rotate to minimize the total energy of the system. Once equilibrated
in energy for a given input-output magnetic field pattern-pair the particles
are fully or partially immobilized by cooling the carrier liquid. Thus produced
particle distributions control the memory states, which are read out
magnetically using spin-valve sensors incorporated in the output pads. The
actual memory consists of spin distributions that is dynamic in nature,
realized only in response to the input patterns that the system has been
trained for. Two training algorithms for storing multiple patterns are
investigated. Using Monte Carlo simulations of the physical system we
demonstrate that the device is capable of storing and recalling two sets of
images, each with an accuracy approaching 100%.Comment: submitted to Neural Network
1975 commercial grape spray schedule
"MP 263, 2/75/1.5M"PRE-BLOOM SPRAYS -- BLOOM SPRAYS -- POST-BLOOM SPRAYS -- SUMMER SPRAYSBy W.R. Enns and W.S. Craig (Department of Entomology), A.E. Gaus (Department of Horticulture) and P.W. Steiner, H.W. Shaffer, and E.W. Palm (Department of Plant Pathology
- …