9,258 research outputs found
Radiation-resistant device phenomena
Aluminum oxide thin metal film for electron transport measurement
Is there a renormalization of the 1D conductance in Luttinger Liquid model?
Properties of 1D transport strongly depend on the proper choice of boundary
conditions. It has been frequently stated that the Luttinger Liquid (LL)
conductance is renormalized by the interaction as . To
contest this result I develop a model of 1D LL wire with the interaction
switching off at the infinities. Its solution shows that there is no
renormalization of the universal conductance while the electrons have a free
behavior in the source and drain reservoirs.Comment: 5 pages, RevTex 2.0, attempted repair of tex error
Soft-spectrum gamma-ray bursts
A typical gamma to ray burst (GRB), when observed over the approximately 30 keV to 1 MeV range, has a 1 to 10 s duration and a spectrum describable in terms of a several-hundred-keV exponential function. However, KONUS data indicate that some GRBs may belong to a separate class of short (approximately 0.1 s), soft (kT 50 keV) events. This result has been questioned because the KONUS experiments, with only 4 s spectral time resolution and a lack of information approximately 30 keV, are not particularly well suited for the detection and study of these bursts. The UC Berkely/Los Alamos Solar X-Ray Spectrometer/GRB experiment on the International Cometry Explorer (ICE), with nearly continuous coverage of approxiomately one-sixth of the sky down to 5 keV at 0.5 s resolution, is better designed for such a task. Using ICE data, it was confirmed that soft-spectrum events do indeed exist, apparently with properties that set them apart from the general GRB population. Results from the ICE experiment are presented
Many-body dispersions in interacting ballistic quantum wires
We have measured the collective excitation spectrum of interacting electrons
in one-dimension. The experiment consists of controlling the energy and
momentum of electrons tunneling between two clean and closely situated,
parallel quantum wires in a GaAs/AlGaAs heterostructure while measuring the
resulting conductance. We measure excitation spectra that clearly deviate from
the non-interacting spectrum, attesting to the importance of Coulomb
interactions. Notable is an observed 30% enhancement of the velocity of the
main excitation branch relative to non-interacting electrons with the same
density. In short wires, finite size effects resulting from broken
translational invariance are observed. Spin - charge separation is manifested
through moire patterns, reflecting different spin and charge excitation
velocities.Comment: 14 pages, 6 eps figures. To be published in NANOWIRE, a special issue
of Solid State Communication
The HD 192263 system: planetary orbital period and stellar variability disentangled
As part of the Transit Ephemeris Refinement and Monitoring Survey (TERMS), we
present new radial velocities and photometry of the HD 192263 system. Our
analysis of the already available Keck-HIRES and CORALIE radial velocity
measurements together with the five new Keck measurements we report in this
paper results in improved orbital parameters for the system. We derive
constraints on the size and phase location of the transit window for HD
192263b, a Jupiter-mass planet with a period of 24.3587 \pm 0.0022 days. We use
10 years of Automated Photoelectric Telescope (APT) photometry to analyze the
stellar variability and search for planetary transits. We find continuing
evidence of spot activity with periods near 23.4 days. The shape of the
corresponding photometric variations changes over time, giving rise to not one
but several Fourier peaks near this value. However, none of these frequencies
coincides with the planet's orbital period and thus we find no evidence of
star-planet interactions in the system. We attribute the ~23-day variability to
stellar rotation. There are also indications of spot variations on longer (8
years) timescales. Finally, we use the photometric data to exclude transits for
a planet with the predicted radius of 1.09 RJ, and as small as 0.79 RJ.Comment: 9 pages, 6 tables, 6 figures; accepted to Ap
Platelet-Rich Plasma Injection With Percutaneous Needling for Recalcitrant Lateral Epicondylitis: Comparison of Tenotomy and Fenestration Techniques.
Background: Recalcitrant lateral epicondylitis (LE) is a common debilitating condition, with numerous treatment options of varying success. An injection of platelet-rich plasma (PRP) has been shown to improve LE, although it is unclear whether the method of needling used in conjunction with a PRP injection is of clinical importance.
Purpose: To determine whether percutaneous needle tenotomy is superior to percutaneous needle fenestration when each is combined with a PRP injection for the treatment of recalcitrant LE.
Study Design: Cohort study; Level of evidence, 3.
Methods: A total of 93 patients with recalcitrant LE were treated with a PRP injection and percutaneous needle fenestration (n = 45) or percutaneous needle tenotomy (n = 48) over a 5-year study interval. Preoperative patient data, including visual analog scale for pain (VAS-P), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), and Patient-Rated Tennis Elbow Evaluation (PRTEE) scores and grip strength, were obtained from a chart review and compared with postoperative values obtained prospectively. Secondary outcomes included the incidence of complications, need for additional interventions, return to work, and patient satisfaction.
Results: At a mean follow-up of 40 months, significant improvements in VAS-P (mean, -6.1; 95% CI, -6.8 to -5.5; P \u3c .0001), QuickDASH (mean, -46; 95% CI, -52 to -40; P \u3c .0001), and PRTEE (mean, -57; 95% CI, -64 to -50; P \u3c .0001) scores and grip strength (mean, +6.1 kg; 95% CI, 4.9 to 7.3; P \u3c .0001) were observed across the entire study cohort, with no significant differences noted between the fenestration and tenotomy groups. Nine of 45 patients (22%) underwent additional procedures to treat recurrent symptoms in the fenestration group compared with 5 of 48 patients (10%) in the tenotomy group (P = .05). No complications occurred in any patients, and no patients expressed dissatisfaction with their treatment course.
Conclusion: A PRP injection with concomitant percutaneous needling is an effective treatment for recalcitrant LE, with sustained improvements in pain, strength, and function demonstrated at a mean follow-up of longer than 3 years. Although the method of concomitant needling does not appear to have a significant effect on treatment outcomes, more aggressive needle tenotomy is less likely to require conversion to open tenotomy than needle fenestration in the short term to midterm
Experimental Predictions of The Functional Response of A Freshwater Fish
The functional response is the relationship between the feeding rate of an animal and its food density. It is reliant on two basic parameters; the volume searched for prey per unit time (searching rate) and the time taken to consume each prey item (handling time). As fish functional responses can be difficult to determine directly, it may be more feasible to measure their underlying behavioural parameters in controlled conditions and use these to predict the functional response. Here, we tested how accurately a Type II functional response model predicted the observed functional response of roach Rutilus rutilus, a visually foraging fish, and compared it with Type I functional response. Foraging experiments were performed by exposing fish in tank aquaria to a range of food densities, with their response captured using a two-camera videography system. This system was validated and was able to accurately measure fish behaviour in the aquaria, and enabled estimates of fish reaction distance, swimming speed (from which searching rate was calculated) and handling time to be measured. The parameterised Type II functional response model accurately predicted the observed functional response and was superior to the Type I model. These outputs suggest it will be possible to accurately measure behavioural parameters in other animal species and use these to predict the functional response in situations where it cannot be observed directly
Spin Injection into a Luttinger Liquid
We study the effect of spin injection into a Luttinger liquid. The
spin-injection-detection setup of Johnson and Silsbee is considered; here spins
injected into the Luttinger liquid induce, across an interface with a
ferromagnetic metal, either a spin-dependent current () or a
spin-dependent boundary voltage (). We find that the spin-charge
separation nature of the Luttinger liquid affects and in a very
different fashion. In particular, in the Ohmic regime, depends on the
spin transport properties of the Luttinger liquid in essentially the same way
as it would in the case of a Fermi liquid. The implications of our results for
the spin-injection-detection experiments in the high cuprates are
discussed.Comment: 4 pages, REVTEX, 2 figures. Minor changes and corrections to typos.
To appear in Phys. Rev. Let
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