Strategic Targeted Advertising and Market Fragmentation

This paper proves that oligopolistic price competition with both targeted advertising and targeted prices can lead to a permanent fragmentation of the market into a local monopoly. However, compared to mass advertising, targeting increases social welfare and turns out to be more beneficial for consumers than for firms.discount coupons.

How cyclical do cyclically-adjusted balances remain? An EU study

Observed budget balances are an imperfect indicator of the fiscal policy stance, because fluctuations in economic activity induce automatic changes in the balance, hence the use of cyclically-adjusted balances (CAB). However, this paper shows that CABs (as measured through one of the two methods currently used by the Commission) tend to be systematically overestimated during downturns and underestimated during expansions. The dominant source of this distortion arises from the filtering of revenues deemed to be cyclical, possibly signalling a problem with the computation of elasticities. The effect of the items which are assumed not to move with the cycle is non significant, but this overall result conceals offseting effects: public investment turns to be significantly procyclical and interest payments and transfers to firms are countercyclical.Structural balances, output gap

Mirror symmetry on K3 surfaces via Fourier-Mukai transform

We use a relative Fourier-Mukai transform on elliptic K3 surfaces $X$ to describe mirror symmetry. The action of this Fourier-Mukai transform on the cohomology ring of $X$ reproduces relative T-duality and provides an infinitesimal isometry of the moduli space of algebraic structures on $X$ which, in view of the triviality of the quantum cohomology of K3 surfaces, can be interpreted as mirror symmetry.Comment: 15 pages, AMS-LaTeX v1.2. Final version to appear in Commun. Math. Phy

RCC NDE Update

This slide presentation reviews non-destructive evaluation (NDE) techniques of Reinforced Carbon-Carbon (RCC) materials and the progress involved in bringing the technology to technological maturity. Included is information about the test specimens, thermographic, ultrasonic, eddy current, and radiographic inspection of RCC materials

Development of Non Destructive Evaluation Techniques for the In-Situ Inspection of the Orbiter's Thermal Protection System

One of the Columbia Accident Investigation Board's (CAB) recommendation is to develop and implement an inspection plan to determine the structural integrity of all Reinforced Carbon-Carbon (RCC) system components that make part of the Space Shuttle's thermal protection system. This presentation focuses on the efforts to leverage non-destructive evaluation (NDE) expertise from academia, private industry, and government agencies resulting in the design of a comprehensive health monitoring program for RCC components. The different NDE techniques that were considered are presented along with the chosen techniques and preliminary inspection results of RCC materials

An Engineering Look at Space Shuttle and ISS Operations

This slide presentation, in Spanish, is an overview of NASA's Space Shuttle operations and preparations for serving the International Space Station. There is information and or views of the shuttle's design, the propulsion system, the external tanks, the foam insulation, the reusable solid rocket motors, the vehicle assembly building (VAB), the mobile launcher platform being moved from the VAB to the launch pad. There is a presentation of some of the current issues with the space shuttle: cracks in the LH2 flow lines, corrosion and pitting, the thermal protection system, and inspection of the thermal protection system while in orbit. The shuttle system has served for more than 20 years, it is still a challenge to re-certify the vehicles for flight. Materials and material science remain as chief concerns for the shuttle