4,316 research outputs found
CAUSES OF RETAIL PRICE FIXITY: AN EMPIRICAL ANALYSIS
Existing empirical studies do not provide a unifying explanation for retail price fixity. However, economic hysteresis, or the persistence of an economic phenomenon after its initial cause has disappeared, offers a general explanation. Estimates of an empirical model of retail-price hysteresis using store-level scanner data support our hypothesis.Demand and Price Analysis,
Time-frequency detection of Gravitational Waves
We present a time-frequency method to detect gravitational wave signals in
interferometric data. This robust method can detect signals from poorly modeled
and unmodeled sources. We evaluate the method on simulated data containing
noise and signal components. The noise component approximates initial LIGO
interferometer noise. The signal components have the time and frequency
characteristics postulated by Flanagan and Hughes for binary black hole
coalescence. The signals correspond to binaries with total masses between to and with (optimal filter) signal-to-noise ratios of 7
to 12. The method is implementable in real time, and achieves a coincident
false alarm rate for two detectors 1 per 475 years. At this false
alarm rate, the single detector false dismissal rate for our signal model is as
low as 5.3% at an SNR of 10. We expect to obtain similar or better detection
rates with this method for any signal of similar power that satisfies certain
adiabaticity criteria. Because optimal filtering requires knowledge of the
signal waveform to high precision, we argue that this method is likely to
detect signals that are undetectable by optimal filtering, which is at present
the best developed detection method for transient sources of gravitational
waves.Comment: 24 pages, 5 figures, uses REVTE
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Photovoltaic and Behind-the-Meter Battery Storage: Advanced Smart Inverter Controls and Field Demonstration
Mathematical models for sleep-wake dynamics: comparison of the two-process model and a mutual inhibition neuronal model
Sleep is essential for the maintenance of the brain and the body, yet many
features of sleep are poorly understood and mathematical models are an
important tool for probing proposed biological mechanisms. The most well-known
mathematical model of sleep regulation, the two-process model, models the
sleep-wake cycle by two oscillators: a circadian oscillator and a homeostatic
oscillator. An alternative, more recent, model considers the mutual inhibition
of sleep promoting neurons and the ascending arousal system regulated by
homeostatic and circadian processes. Here we show there are fundamental
similarities between these two models. The implications are illustrated with
two important sleep-wake phenomena. Firstly, we show that in the two-process
model, transitions between different numbers of daily sleep episodes occur at
grazing bifurcations.This provides the theoretical underpinning for numerical
results showing that the sleep patterns of many mammals can be explained by the
mutual inhibition model. Secondly, we show that when sleep deprivation disrupts
the sleep-wake cycle, ostensibly different measures of sleepiness in the two
models are closely related. The demonstration of the mathematical similarities
of the two models is valuable because not only does it allow some features of
the two-process model to be interpreted physiologically but it also means that
knowledge gained from study of the two-process model can be used to inform
understanding of the mutual inhibition model. This is important because the
mutual inhibition model and its extensions are increasingly being used as a
tool to understand a diverse range of sleep-wake phenomena such as the design
of optimal shift-patterns, yet the values it uses for parameters associated
with the circadian and homeostatic processes are very different from those that
have been experimentally measured in the context of the two-process model
Imperfect Exchange Rate Passthrough: Strategic Pricing and Menu Costs
A large body of literature finds that exporters do not pass nominal exchange rate movements fully through to destination market prices over short time horizons. This imperfect passthrough has been widely attributed to strategic âpricing-to-marketâ, whereby exporters deliberately accept changes in the home currency value of export prices in order to gain or defend market share. We show that imperfect passthrough in the short run may also arise from simple menu costs. In contrast to strategic pricing, however, the long run passthrough is complete under menu costs â with associated implications for trade adjustment. Examining the cover prices of two magazines, The Economist and Business Week, we find support for menu costs as a partial explanation of imperfect passthrough.
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