A Threshold Model of Real US GDP and the Problem of Constructing Confidence Intervals in TAR Models

We estimate real U.S. GDP growth as a threshold autoregressive process, and construct confidence intervals for the parameter estimates. However, there are various approaches that can be used in constructing the confidence intervals. Specifically, standard- t , bootstrap- t , and bootstrap-percentile confidence intervals are simulated for the slope coefficients and the estimated threshold. However, the results for the different methods have very different economic implications. We perform a Monte Carlo experiment to evaluate the various methods.Bootstrap GDP; Threshold Autoregression; Bootstrap Confidence Intervals

Summary Proceedings of a Wind Shear Workshop

A number of recent program results and current issues were addressed: the data collection phase of the highly successful Joint Airport Weather Study (JAWS) Project and the NASA-B5f7B Gust Gradient Program, the use of these data for flight crew training through educational programs (e.g., films) and with manned flight training simulators, methods for post-accident determination of wind conditions from flight data recorders, the microburst wind shear phenomenon which was positively measured and described the ring vortex as a possible generating mechanism, the optimum flight procedure for use during an unexpected wind shear encounter, evaluation of the low-level wind shear alert system (LLWSAS), and assessment of the demonstrated and viable application of Doppler radar as an operational wind shear warning and detection system

Use of aircraft for zero-gravity environment

Use of aircraft as test vehicle to produce zero gravity or weightlessness environmen

Resonant tunneling of electromagnetic waves through polariton gaps

We consider resonant tunneling of electromagnetic waves through an optical barrier formed by dielectric layers with the frequency dispersion of their dielectric permiability. The frequency region between lower and upper polariton branches in these materials presents a stop band for electromagnetic waves. We show that resonance tunneling through this kind of barriers is qualitatevely different from tunneling through other kind of optical barriers as well as from quantum mechanic tunneling through a rectangular barrier. We find that the width of the resonance maxima of the transmission coeffcient tends to zero as frequency approach the lower boundary of the stop band in a very sharp non-analytical way. Resonance transmission peaks give rise to new photonic bands inside the stop band if one considers periodical array of the layers.Comment: 8 pages, 5 figure

How Do Tourists React to Political Violence? An Empirical Analysis of Tourism in Egypt

This paper uses a detailed database of political violence in Egypt to study European and US tourists' attitudes towards a conflict region. We study the heterogeneous impacts of different dimensions of political violence and counter-violence on tourist flows to Egypt in the 1990s. Both US and EU tourists respond negatively to attacks on tourists, but are not influenced by casualties arising in confrontations between domestic groups. However, European tourists are sensitive to the counter-violence measures implemented by the Egyptian government. There is also evidence of arrivals of tourists into Egypt rising when fatalities in the Israeli/Palestinian conflict increase.</p

Political opportunism and countercyclical fiscal policy in election-year recessions

Political budget cycles (PBCs) have been well documented in the literature, albeit not for all circumstances. Similarly, there is clear evidence on the positive effect of economic growth on electoral success. However, no work has been done on the impact of economic growth on the magnitude of PBCs. The theoretical model argues that a government has an incentive to increase fiscal manipulations when a recession is expected to hit and curtail reelection chances; this amounts to countercyclical policy for opportunistic rather than Keynesian motives. Very robust evidence for this behavior is found in Portuguese municipalities; in election years, budget deficits go up even more and significantly so, when a recession is expected.Fundação para a Ciência e Tecnologia (FCT

Do Spin-Offs Make the Academics’ Heads Spin?: The Impacts of Spin-Off Companies on Their Parent Research Organisation

As public research organisations are increasingly driven by their national and regional governments to engage in knowledge transfer, they have started to support the creation of companies. These research based spin-off companies (RBSOs) often keep contacts with the research institutes they originate from. In this paper we present the results of a study of four research institutes within two universities and two non-university public research organisations (PROs) in the Netherlands. We show that research organisations have distinct motivations to support the creation of spin-off companies. In terms of resources RBSOs contribute, mostly in a modest way, to research activities by providing information, equipment and monetary resources. In particular, RBSOs are helpful for researchers competing for research grants that demand participation of industry. Furthermore, RBSOs may be seen as a proactive response by Dutch public research organisations to demands of economic relevance from their institutional environment. RBSOs enhance the prestige of their parent organisations and create legitimacy for public funds invested in PROs. At the same time, most RBSOs do not have a significant impact on the direction of the research conducted at the PROs