Credit card default losses increased dramatically in the 80s and 90s, from 3% to over 5% of outstanding debt. We explore whether technological progress in debt collection is behind this change by developing a new theory featuring costly state verification with signals. We motivate our approach by the predominance of informal bankruptcy in the credit card market, which necessitates the costly in...

The aerodynamic performance of hovering insects is largely explained by the presence of a stably attached leading edge vortex (LEV) on top of their wings. Although LEVs have been visualized on real, physically modeled, and simulated insects, the physical mechanisms responsible for their stability are poorly understood. To gain fundamental insight into LEV stability on flapping fly wings we expr...

In this article, I study how the presence of a revolving door and potential collusion between a regulator and a regulated firm affect the regulator's performance incentives. Contrary to the conventional wisdom, these seemingly undesirable features of the regulatory system may serve the interests of the government because (i) the regulator's efforts to enhance her industry qualifications may hav...

We investigated the three-dimensional vorticity dynamics of the flows generated by revolving wings using a volumetric 3-component velocimetry system. The threedimensional velocity and vorticity fields were represented with respect to the base axes of rotating Cartesian reference frames, and the second invariant of the velocity gradient was evaluated and used as a criterion to identify two core ...

We present an all-magnetic scheme for the assembly and study of magnetic dipoles within designed confinement profiles that are activated on micro-patterned permalloy films through a precessing magnetic field. Independent control over the confinement and dipolar interactions is achieved by tuning the strength and orientation of the revolving field. The technique is demonstrated with superparamag...

Unfortunately, many small communities in Illinois are served by private septic systems that are failing, resulting in serious health problems for the community. These small rural communities are often populated by residents living on low to moderate incomes, who cannot afford the cost of a conventional sewer system. As funding sources become more scarce due to government budget cuts and a shift...

1. Comparative research and generalisations in lotic ecology are challenged by the dynamic hydrology of fluvial systems. The aim of this study was to understand more fully how factors such as light, nutrients and flow can predict variation in autochthonous production and algal biomass. 2. We measured seasonal changes in percent bankfull discharge, inorganic nutrient concentrations, turbidity, i...

A newly invented compressor, namely revolving vane compressor (RV) has been introduced two years ago (Teh and Ooi, 2006, 2006, 2006). This paper presents the improved version (Teh and Ooi, 2007) of the RV, called RV-i, where “i” stands for improved. The RV or RV-i is designed with the intention to overcome most of the limitations facing the working characteristics of the rolling piston compress...

Over the years, rotary compressors have gained significant popularity and widespread usage because of their compact nature and good vibration characteristics. Although possessing many advantages over the reciprocating compressors, one of the performance limitations of the rotary machines is their inferior mechanical efficiency due to the existence of large frictional losses, which occurs as a r...

Much of what is known about the regulation of circadian rhythms has stemmed from the induction, recognition, or manufacture of genetic variants. Such investigations have been especially salient in chronobiological analyses of Drosophila. Many starting points for elucidation of rhythmic processes operating in this insect entailed the isolation of mutants or the design of engineered gene modifica...