Search results for "GRAVITY"

Heterogeneous Firms, Globalisation and the Distance Puzzle

2015

Despite the strong pace of globalisation, the distance effect on trade is persistent or even growing over time (Disdier and Head, 2008). To solve this distance puzzle, we use the recently developed gravity equation estimator from Helpman et al. (2008) (HMR henceforth). Using three different data sets, we find that the distance coefficient increases over time when ordinary least squares (OLS) is used, while the non-linear estimation of HMR leads to a decline in the distance coefficient over time. The distance puzzle, thus, arises from a growing bias of OLS estimates. The latter is explained by an increase in the importance of the bias from omitting the number of heterogeneous exporting firms…

Do nonreciprocal preferential trade agreements increase beneficiaries' exports?

2014

Abstract This paper investigates whether and to what extent nonreciprocal preferential trade agreements (NRPTAs) have increased developing countries' exports to richer countries. Using recent developments in the econometric analysis of the gravity equation over the period 1960–2008, we find robust evidence that, on the whole, NRPTAs and the Generalized System of Preferences have had an economically significant effect on exports from developing countries. However, the estimation of catch-all dummies masks heterogeneous results for the individual programs.

The impact of embassies and consulates on tourism

2007

Abstract This paper estimates the effect of embassies and consulates on tourist flows from the G-7 countries. The results indicate that embassies and consulates have a positive and significant effect on tourism that ranges between 15% and 30% depending on the estimation technique. Moreover, the impact is larger for the sample of developing countries. The disaggregated analysis shows that, after controlling for both origin and destination fixed effects, a significant impact is found in the seven origin countries.

Optical Dark Rogue Wave

2016

AbstractPhotonics enables to develop simple lab experiments that mimic water rogue wave generation phenomena, as well as relativistic gravitational effects such as event horizons, gravitational lensing and Hawking radiation. The basis for analog gravity experiments is light propagation through an effective moving medium obtained via the nonlinear response of the material. So far, analogue gravity kinematics was reproduced in scalar optical wave propagation test models. Multimode and spatiotemporal nonlinear interactions exhibit a rich spectrum of excitations, which may substantially expand the range of rogue wave phenomena and lead to novel space-time analogies, for example with multi-parti…

Constraining effective rheology through parallel joint geodynamic inversion

2014

Abstract The dynamics of crust and lithosphere is to a large extent controlled by its effective viscosity. Unfortunately, extrapolation of laboratory experiments indicates that viscosity is likely to vary over many orders of magnitude. Additional methods are thus required to constrain the effective viscosity of the present-day lithosphere using more direct geophysical observations. Here we discuss a method, which couples 3D geodynamic models with observations (surface velocities and gravity anomalies) and with a Bayesian inversion scheme on massively parallel high performance computers. We illustrate that the basic principle of a joint geodynamic and gravity inversion works well with a simp…

Depletion in Bose-Einstein condensates using quantum field theory in curved space

2007

5 pages.-- PACS nrs.: 03.75.Kk; 05.30.Jp; 04.62.+v; 04.70.Dy.-- ISI Article Identifier: 000246074600122.-- ArXiv pre-print available at: http://arxiv.org/abs/cond-mat/0610367

Observations and Field Activities

2009

The Structure of Financial Networks

2010

We present here an overview of the use of networks in Finance and Economics. We show how this approach enables us to address important questions as, for example, the structure of control chains in financial systems, the systemic risk associated with them and the evolution of trade between nations. All these results are new in the field and allow for a better understanding and modelling of different economic systems.

Homeward Bound FDI: Are Migrants a Bridge over Trouble Finance?

2016

Migrants can lower cross-border investment barriers, help investors by providing information about their homeland and reduce transaction costs by sharing expertise on regulations, customs and procedures. In addition to generating these well-known networking effects, migrants can also provide valuable information about local finance, thereby easing the credit constraints foreign investors faced during the 2007 financial crisis. This paper sheds new light on the underlying mechanisms through which migration may affect foreign investment in the migrant's homeland by distinguishing between the effects on FDI's intensive and extensive margins. Gravity estimates for 140 countries for the period 2…

The capillary waves' contribution to wind-wave generation

2022

Published theories and observations have shown that dissipation of gravity waves implies frequency downshifting of wave energy. Hence, for wind-waves, the wind energy input to the highest frequencies is of special interest. Here it is shown that this input is vital, because the direct wind energy input obtained by the air-pressure’s work on most gravity waves is slightly less than what the waves need to grow. Further, the wind’s input of the angular momentum that waves need to grow is found to be absent at most gravity wave frequencies. The capillary waves that appear at the surface of the sea when the wind is blowing solve these problems. To demonstrate this, an extension of linear wave th…