Household Demand for Employer-Based Health Insurance

We use the 1996 Medical Expenditure Panel Survey to estimate a model of household demand for employer-based health insurance, explicitly investigating differences in behavior between households with two potential sources of coverage and those with one source. Own and cross-price elasticities are estimated for three types of health plans, including exclusive provider organizations, any provider organizations, and mixed provider organizations. We find that the premium, family size, income, and wealth significantly affect demand. Our elasticity estimates reveal an overall, small behavioral response to changes in price with respect to health plan switching and take-up. Finally, we discuss the implications of our findings with respect to employer benefit design.

Entry and Competition in Local Hospital Markets

There has been considerable consolidation in the hospital industry in recent years. Over 900 deals occurred from 1994-2000, and many local markets, even in large urban areas, have been reduced to monopolies, duopolies or triopolies. This surge in consolidation has led to concern about its effect on competition in local markets for hospital services. In this paper we examine the impact of market structure on competition in local hospital markets – specifically, does competition increase with the number of firms? We extend the entry model developed by Bresnahan and Reiss to make use of quantity information and apply it to data on the US hospital industry. The results from the estimation are striking. In the hospital markets we examine, entry leads to markets quickly becoming competitive. Entry reduces variable profits and increases quality. Indeed, most of the effects of entry come from having a second and possibly a third firm enter the market. The use of quantity information allows us to infer that entry is welfare increasing.analysis of health care markets

Advanced Coordinated Beamforming for the Downlink of Future LTE Cellular Networks

Modern cellular networks in traditional frequency bands are notoriously interference-limited especially in urban areas, where base stations are deployed in close proximity to one another. The latest releases of Long Term Evolution (LTE) incorporate features for coordinating downlink transmissions as an efficient means of managing interference. Recent field trial results and theoretical studies of the performance of joint transmission (JT) coordinated multi-point (CoMP) schemes revealed, however, that their gains are not as high as initially expected, despite the large coordination overhead. These schemes are known to be very sensitive to defects in synchronization or information exchange between coordinating bases stations as well as uncoordinated interference. In this article, we review recent advanced coordinated beamforming (CB) schemes as alternatives, requiring less overhead than JT CoMP while achieving good performance in realistic conditions. By stipulating that, in certain LTE scenarios of increasing interest, uncoordinated interference constitutes a major factor in the performance of CoMP techniques at large, we hereby assess the resilience of the state-of-the-art CB to uncoordinated interference. We also describe how these techniques can leverage the latest specifications of current cellular networks, and how they may perform when we consider standardized feedback and coordination. This allows us to identify some key roadblocks and research directions to address as LTE evolves towards the future of mobile communications.Comment: 16 pages, 6 figures, accepted to IEEE Communications Magazin

Beneficial hemodynamic effects of inhibiting ANP catabolism in congestive heart failure

Pepper, Beverly (escultora)Primer pla de l'obra. També conegut com a "Cel caigut, Espiral arbrada", realitzat amb ceràmica

High sensitivity variable-temperature infrared nanoscopy of conducting oxide interfaces

Probing the local transport properties of two-dimensional electron systems (2DES) confined at buried interfaces requires a non-invasive technique with a high spatial resolution operating in a broad temperature range. In this paper, we investigate the scattering-type scanning near field optical microscopy as a tool for studying the conducting LaAlO3/SrTiO3 interface from room temperature down to 6 K. We show that the near-field optical signal, in particular its phase component, is highly sensitive to the transport properties of the electron system present at the interface. Our modelling reveals that such sensitivity originates from the interaction of the AFM tip with coupled plasmon-phonon modes with a small penetration depth. The model allows us to quantitatively correlate changes in the optical signal with the variation of the 2DES transport properties induced by cooling and by electrostatic gating. To probe the spatial resolution of the technique, we image conducting nano-channels written in insulating heterostructures with a voltage-biased tip of an atomic force microscope.Comment: 19 pages, 5 figure

Les salicornietum emerici et ramosissimae du littoral méditerranéen français

En este trabajo, los áutores señalan precisiones taxonómicas y corológicas sobre las Salicornias anuales del litoral mediterráneo francés. Salicornia emerie!, tetraploide y Salicornia ramosissima diploide tienen una distribución mediterránea, atlántica alcanzando Bretaña y el 5. de Inglaterra. En el Mediterráneo definen dos asociaciones territoriales, Arthocnemo-Salieornietum emerieiy Arthorocnemo-Salicornietum ramosissimae la primera en la franja interna y la segunda en la franja externa de las lagunas sobre sustrato mineral clorurado y sujeto a desecación estival

An acoustic analog to the dynamical Casimir effect in a Bose-Einstein condensate

We have realized an acoustic analog to the Dynamical Casimir effect. The density of a trapped Bose-Einstein condensate is modulated by changing the trap stiffness. We observe the creation of correlated excitations with equal and opposite momenta, and show that for a well defined modulation frequency, the frequency of the excitations is half that of the trap modulation frequency.Comment: Includes supplemental informatio

Spontaneous Four-Wave Mixing of de Broglie Waves: Beyond Optics

We investigate the atom-optical analog of degenerate four-wave mixing of photons by colliding two Bose-Einstein condensates (BECs) of metastable helium and measuring the resulting momentum distribution of the scattered atoms with a time and space resolved detector. For the case of photons, phase matching conditions completely define the final state of the system, and in the case of two colliding BECs, simple analogy implies a spherical momentum distribution of scattered atoms. We find, however, that the final momenta of the scattered atoms instead lie on an ellipsoid whose radii are smaller than the initial collision momentum. Numerical and analytical calculations agree well with the measurements, and reveal the interplay between many-body effects, mean-field interaction, and the anisotropy of the source condensate