To what extent are investment bank-differentiating factors relevant for firms floating moderate-sized IPOs?

One explanation provided for the relatively high and increasingly stable spreads for moderate-sized IPOs ($20-$80 million) documented in Chen and Ritter (2000) is that issuing firms focus less on price and more on a combination of investment bank-differentiating factors (such as underwriter prestige, analyst coverage, industry expertise, under-pricing, price stabilization activities, liquidity provision, and so on,) and banks use industry-based differentiation as a source of market power. Using a new approach developed in a model of firm location choice due to Ellison and Glaeser (1997), this paper presents some evidence on the combined relevance of such bank-differentiating factors, over and above bank size, for firms choosing investment banks for floating IPOs. For moderate-sized IPOs, there is a little, but not much evidence that such factors are a good explanation for high and increasingly stable spreads. Other than in a few of the largest industries, bank-differentiating factors are not significantly relevant for a large proportion of industries. Moreover, one aggregate measure of differentiation is declining over time.Investment Banking, Initial Public Offering, Differentiating Factors, Concentration, 7 percent puzzle

CMB power spectrum estimation using noncircular beams

The measurements of the angular power spectrum of the Cosmic Microwave Background (CMB) anisotropy has proved crucial to the emergence of cosmology as a precision science in recent years. In this remarkable data rich period, the limitations to precision now arise from the the inability to account for finer systematic effects in data analysis. The non-circularity of the experimental beam has become progressively important as CMB experiments strive to attain higher angular resolution and sensitivity. We present an analytic framework for studying the leading order effects of a non-circular beam on the CMB power spectrum estimation. We consider a non-circular beam of fixed shape but variable orientation. We compute the bias in the pseudo-$C_l$ power spectrum estimator and then construct an unbiased estimator using the bias matrix. The covariance matrix of the unbiased estimator is computed for smooth, non-circular beams. Quantitative results are shown for CMB maps made by a \emph{hypothetical} experiment with a non-circular beam comparable to our fits to the WMAP beam maps described in the appendix and uses a \emph{toy} scan strategy. We find that significant effects on CMB power spectrum can arise due to non-circular beam on multipoles comparable to, and beyond, the inverse average beam-width where the pseudo-$C_l$ approach may be the method of choice due to computational limitations of analyzing the large datasets from current and near future CMB experiments.Comment: 23 pages, 12 eps figures, uses RevTeX 4. Matches version accepted to Phys. Rev. D. Corrected minor typographical error in the final expression [eqn (3.23)] (post publication

Slow pressure modes in thin accretion discs

Thin accretion discs around massive compact objects can support slow pressure modes of oscillations in the linear regime that have azimuthal wavenumber $m=1$. We consider finite, flat discs composed of barotropic fluid for various surface density profiles and demonstrate--through WKB analysis and numerical solution of the eigenvalue problem--that these modes are stable and have spatial scales comparable to the size of the disc. We show that the eigenvalue equation can be mapped to a Schr\"odinger-like equation. Analysis of this equation shows that all eigenmodes have discrete spectra. We find that all the models we have considered support negative frequency eigenmodes; however, the positive eigenfrequency modes are only present in power law discs, albeit for physically uninteresting values of the power law index $\beta$ and barotropic index $\gamma$.Comment: 9 pages, 7 figures, 1 table, accepted in MNRAS for pulicatio

A Comparative Study Between a Micromechanical Cantilever Resonator and MEMS-based Passives for Band-pass Filtering Application

Over the past few years, significant growth has been observed in using MEMS based passive components in the RF microelectronics domain, especially in transceiver components. This is due to some excellent properties of the MEMS devices like low loss, excellent isolation etc. in the microwave frequency domain where the on-chip passives normally tend to become leakier and degrades the transceiver performance. This paper presents a comparative analysis between MEMS-resonator based and MEMS-passives based band-pass filter configurations for RF applications, along with their design, simulation, fabrication and characterization. The filters were designed to have a center frequency of 455 kHz, meant for use as the intermediate frequency (IF) filter in superheterodyne receivers. The filter structures have been fabricated in PolyMUMPs process, a three-polysilicon layer surface micromachining process.Comment: 6 pages, 15 figure

Window Function for Non-Circular Beam CMB Anisotropy Experiment

We develop computationally rapid methods to compute the window function for a cosmic microwave background anisotropy experiment with a non-circular beam which scans over large angles on the sky. To concretely illustrate these methods we compute the window function for the Python V experiment which scans over large angles on the sky with an elliptical Gaussian beam.Comment: 27 pages, 5 figure