300,147 research outputs found
Pricing under innovation
We study pricing when firms introduce process and product innovations over
time. We set up a model of endogenous productivity and markup under imperfect
competition and dynamic pricing. We estimate it using output price indices
reported by an unbalanced panel of 2,300 Spanish manufacturing firms during
1990-2006. Markups turn out to be procyclical and change with the introduction
of innovations. Firms use innovation to increase margins, but product innovators
are careful to raise prices on new or improved goods. Process innovations tend to
leave prices unchanged, product innovations tend to raise prices and firms that
introduce both tend to decrease them
Neutrino scattering in supernovae and spin correlations of a unitary gas
Core collapse supernova simulations can be sensitive to neutrino interactions
near the neutrinosphere. This is the surface of last scattering. We model the
neutrinosphere region as a warm unitary gas of neutrons. A unitary gas is a low
density system of particles with large scattering lengths. We calculate
modifications to neutrino scattering cross sections because of the universal
spin and density correlations of a unitary gas. These correlations can be
studied in laboratory cold atom experiments. We find significant reductions in
cross sections, compared to free space interactions, even at relatively low
densities. These reductions could reduce the delay time from core bounce to
successful explosion in multidimensional supernova simulations.Comment: 5 pages, 2 figures, minor corrections in response to referee, Phys.
Rev. C in pres
Comparison between TeV and non-TeV BL Lac Objects
BL Lacertae objects (BL Lacs) is the dominant population of TeV emitting
blazars. In this work, we investigate whether there is any special
observational properties for TeV sources. To do so, we will compare the
observational properties of TeV detected BL Lacs (TeV BLs) and non-TeV detected
BL Lac objects (non-TeV BLs). From the 3rd /LAT catalog (3FGL), we can
get 662 BL Lacs, out of which, 47 are TeV BLs and 615 are non-TeV BLs. Their
multi-wavelength flux densities (, , ,
), photon spectral indexes (,
), and effective spectral indexes (
and ) are compiled from the available literatures. Then the
luminosities (, ,
, ) are calculated. From
comparisons, we found that TeV BLs are different from low-synchrotron-peaked
BLs (LSP) and intermediate-synchrotron-peaked BLs (ISP), but TeV BLs show
similar properties as high-synchrotron-peaked BLs (HSP). Therefore, we
concentrated on comparison between TeV HSP BLs and non-TeV HSP BLs. Analysis
results suggest that TeV HSP BLs and non-TeV HSP BLs show some differences in
their and , while their other
properties are quite similar
Telomere length as a predictor of response to Pioglitazone in patients with unremitted depression: a preliminary study.
We studied peripheral leukocyte telomere length (LTL) as a predictor of antidepressant response to PPAR-γ agonist in patients with unremitted depression. In addition we examined correlation between LTL and the insulin resistance (IR) status in these subjects. Forty-two medically stable men and women ages 23-71 with non-remitted depression participated in double-blind placebo-controlled add-on of Pioglitazone to treatment-as-usual. Oral glucose tolerance tests were administered at baseline and at 12 weeks. Diagnostic evaluation of psychiatric disorders was performed at baseline and mood severity was followed weekly throughout the duration of the trial. At baseline, no differences in LTL were detected by depression severity, duration or chronicity. LTL was also not significantly different between insulin-resistant and insulin-sensitive subjects at baseline. Subjects with longer telomeres exhibited greater declines in depression severity in the active arm, but not in a placebo arm, P=0.005, r=-0.63, 95% confidence interval (95% CI)=(-0.84,-0.21). In addition, LTL predicted improvement in insulin sensitivity in the group overall and did not differ between intervention arms, P=0.036, r=-0.44, 95% CI=(-0.74,0.02) for the active arm, and P=0.026, r=-0.50, 95% CI=(-0.78,-0.03) for the placebo arm. LTL may emerge as a viable predictor of antidepressant response. An association between insulin sensitization and LTL regardless of the baseline IR status points to potential role of LTL as a non-specific moderator of metabolic improvement in these patients
Depolarization-activated potentiation of the T fiber synapse in the blue crab
The blue crab T fiber synapse, associated with the stretch receptor of the swimming leg, has a nonspiking presynaptic element that mediates tonic transmission. This synapse was isolated and a voltage clamp circuit was used to control the membrane potential at the release sites. The dependence of transmitter release on extracellular calcium, [Ca]o, was studied over a range of 2.5-40 mM. A power relationship of 2.7 was obtained between excitatory postsynaptic potential (EPSP) rate of rise and [Ca]o. Brief presynaptic depolarizing steps, 5-10 ms, presented at 0.5 Hz activated EPSP's of constant amplitude. Inserting a 300-ms pulse (conditioning pulse) between these test pulses potentiated the subsequent test EPSPs. This depolarization-activated potentiation (DAP) lasted for 10-20 s and decayed with a single exponential time course. The decay time course remained invariant with test pulse frequencies ranging from 0.11 to 1.1 Hz. The magnitude and decay time course of DAP were independent of the test pulse amplitudes. The magnitude of DAP was a function of conditioning pulse amplitudes. Large conditioning pulses activated large potentiations, whereas the decay time constants were not changed. The DAP is a Ca-dependent process. When the amplitude of conditioning pulses approached the Ca equilibrium potential, the magnitude of potentiation decreased. Repeated application of conditioning pulses, at 2-s intervals, did not produce additional potentiation beyond the level activated by the first conditioning pulse. Comparison of the conditioning EPSP waveforms activated repetitively indicated that potentiation lasted transiently, 100 ms, during a prolonged release. Possible mechanisms of the potentiation are discussed in light of these new findings.The blue crab T fiber synapse, associated with the stretch receptor of the swimming leg, has a nonspiking presynaptic element that mediates tonic transmission. This synapse was isolated and a voltage clamp circuit was used to control the membrane potential at the release sites. The dependence of transmitter release on extracellular calcium, [Ca]o, was studied over a range of 2.5-40 mM. A power relationship of 2.7 was obtained between excitatory postsynaptic potential (EPSP) rate of rise and [Ca]o. Brief presynaptic depolarizing steps, 5-10 ms, presented at 0.5 Hz activated EPSP's of constant amplitude. Inserting a 300-ms pulse (conditioning pulse) between these test pulses potentiated the subsequent test EPSPs. This depolarization-activated potentiation (DAP) lasted for 10-20 s and decayed with a single exponential time course. The decay time course remained invariant with test pulse frequencies ranging from 0.11 to 1.1 Hz. The magnitude and decay time course of DAP were independent of the test pulse amplitudes. The magnitude of DAP was a function of conditioning pulse amplitudes. Large conditioning pulses activated large potentiations, whereas the decay time constants were not changed. The DAP is a Ca-dependent process. When the amplitude of conditioning pulses approached the Ca equilibrium potential, the magnitude of potentiation decreased. Repeated application of conditioning pulses, at 2-s intervals, did not produce additional potentiation beyond the level activated by the first conditioning pulse. Comparison of the conditioning EPSP waveforms activated repetitively indicated that potentiation lasted transiently, 100 ms, during a prolonged release. Possible mechanisms of the potentiation are discussed in light of these new findings.NS-07942 - NINDS NIH HHS; NS-13742 - NINDS NIH HH
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