Dividing the Pie

We examine the consequences of transparency in an experimentalmultiple-dealer market with asymmetrically informed dealers. Fiveprofessional securities traders make a market for a single security.In each trading round, one of the dealers (the "insider") is told thesecurity's true value. We vary both pre-trade and post-tradetransparency by changing the way quote and trade information ispublished. The insider's profits are greatest when price efficiency islowest. Price efficiency, in turn, is reduced by pre-tradetransparency and increased by posttrade transparency. Marketliquidity, measured by dealers' bid-ask spreads, is improved bypre-trade transparency and reduced by post-trade transparency.financial markets;information asymmetry;market microstructure;experimental economics

Measurements of wavelength dependent scattering and backscattering coefficients by low-coherence spectroscopy

Quantitative measurements of scattering properties are invaluable for optical techniques in medicine. However, noninvasive, quantitative measurements of scattering properties over a large wavelength range remain challenging. We introduce low-coherence spectroscopy as a noninvasive method to locally and simultaneously measure scattering μs and backscattering μb coefficients from 480 to 700 nm with 8 nm spectral resolution. The method is tested on media with varying scattering properties (μs = 1 to 34 mm−1 and μb = 2.10−6 to 2.10−3 mm−1), containing different sized polystyrene spheres. The results are in excellent agreement with Mie theor

Quantitative comparison of analysis methods for spectroscopic optical coherence tomography

Spectroscopic optical coherence tomography (sOCT) enables the mapping of chromophore concentrations and image contrast enhancement in tissue. Acquisition of depth resolved spectra by sOCT requires analysis methods with optimal spectral/spatial resolution and spectral recovery. In this article, we quantitatively compare the available methods, i.e. the short time Fourier transform (STFT), wavelet transforms, the Wigner-Ville distribution and the dual window method through simulations in tissue-like media. We conclude that all methods suffer from the trade-off in spectral/spatial resolution, and that the STFT is the optimal method for the specific application of the localized quantification of hemoglobin concentration and oxygen saturation

Initial results of in vivo non-invasive cancer imaging in the human breast using near-infrared photoacoustics

Near-infrared photoacoustic images of regions-of-interest in 4 of the 5 cases of patients with symptomatic breasts reveal higher intensity regions which we attribute to vascular distribution associated with cancer. Of the 2 cases presented here, one is especially significant where benign indicators dominate in conventional radiological images, while photoacoustic images reveal vascular features suggestive of malignancy, which is corroborated by histopathology. The results show that photoacoustic imaging may have potential in visualizing certain breast cancers based on intrinsic optical absorption contrast. A future role for the approach could be in supplementing conventional breast imaging to assist detection and/or diagnosis.\ud \u

Dividing the Pie

We examine the consequences of transparency in an experimental multiple-dealer market with asymmetrically informed dealers. Five professional securities traders make a market for a single security. In each trading round, one of the dealers (the "insider") is told the security's true value. We vary both pre-trade and post-trade transparency by changing the way quote and trade information is published. The insider's profits are greatest when price efficiency is lowest. Price efficiency, in turn, is reduced by pre-trade transparency and increased by posttrade transparency. Market liquidity, measured by dealers' bid-ask spreads, is improved by pre-trade transparency and reduced by post-trade transparency

Enkele aspecten van vegetatie en bodem der duinen van Goeree, in het bijzonder de contactgordels tussen zout en zoet milieu

RIVON onderzoek zout zoet vegetati