Foreign direct investment: flows, volatility and growth in developing countries

This paper contributes to the literature on FDI and economic growth. We deviate from previous studies by introducing measures of the volatility of FDI inflows. As introduced into the model, these are predicted to have a negative effect on growth. We estimate the standard model using cross-section, panel data and instrumental variable techniques. Whilst all results are not entirely robust, there is a consistent finding that FDI has a positive effect on growth whereas volatility of FDI has a negative impact. The evidence for a positive effect of FDI is not sensitive to which other explanatory variables are included. In particular, it is not conditional on the level of human capital (as found in some previous studies). There is a suggestion that it is not the volatility of FDI per se that retards growth but that such volatility captures the growth-retarding effects of unobserved variables.

A multiple scales approach to crack front waves

Perturbation of a propagating crack with a straight edge is solved using the method of matched asymptotic expansions (MAE). This provides a simplified analysis in which the inner and outer solutions are governed by distinct mechanics. The inner solution contains the explicit perturbation and is governed by a quasi-static equation. The outer solution determines the radiation of energy away from the tip, and requires solving dynamic equations in the unperturbed configuration. The outer and inner expansions are matched via the small parameter L/l defined by the disparate length scales: the crack perturbation length L and the outer length scale l associated with the loading. The method is first illustrated for a scalar crack model and then applied to the elastodynamic mode I problem. The dispersion relation for crack front waves is found by requiring that the energy release rate is unaltered under perturbation. The wave speed is calculated as a function of the nondimensional parameter kl where k is the crack front wavenumber, and dispersive properties of the crack front wave speed are described for the first time. The example problems considered here demonstrate that the potential of using MAE for moving boundary value problems with multiple scales.Comment: 25 pages, 5 figure

Income diversification and household welfare in Uganda 1992-2012

We use five waves of household surveys in Uganda, from 1992/3 to 2011/12, to study income diversification and its effect on the welfare of rural and urban households during a period of sustained economic growth and poverty reduction, comparing the 1990s to the 2000s, and disaggregating by gender of the household head. Diversification is measured in terms of access to incomes from agriculture (farming), agricultural wage, self-employment (informal), wage employment and remittances. The analysis shows substantial and evolving variation in the effects of diversification across rural/urban locations and gender of the household head. Diversification became increasingly beneficial for welfare over time in rural areas, particularly for male headed households, but not for female headed households that diversified into agricultural wage employment. Diversification was also important for the livelihoods of urban households, but with large differences across male and female headed households likely reflecting differentials in the returns to non-agricultural employment. Remittances were associated with increasing welfare in the 2000s for all households, although the proportion of households receiving remittances has been declining

Isotopic distribution of fission fragments in collisions between 238U beam and 9Be and 12C targets at 24 MeV/u

Inverse kinematics coupled to a high-resolution spectrometer is used to investigate the isotopic yields of fission fragments produced in reactions between a 238U beam at 24 MeV/u and 9Be and 12C targets. Mass, atomic number and isotopic distributions are reported for the two reactions. These informations give access to the neutron excess and the isotopic distribution widths, which together with the atomic-number and mass distributions are used to investigate the fusion-fission dynamics.Comment: Submitted to PR

Energy radiation of moving cracks

The energy radiated by moving cracks in a discrete background is analyzed. The energy flow through a given surface is expressed in terms of a generalized Poynting vector. The velocity of the crack is determined by the radiation by the crack tip. The radiation becomes more isotropic as the crack velocity approaches the instability threshold.Comment: 7 pages, embedded figure

Evidence for a change in the nuclear mass surface with the discovery of the most neutron-rich nuclei with 17<Z <25

The results of measurements of the production of neutron-rich nuclei by the fragmentation of a 76-Ge beam are presented. The cross sections were measured for a large range of nuclei including fifteen new isotopes that are the most neutron-rich nuclides of the elements chlorine to manganese (50-Cl, 53-Ar, 55,56-K, 57,58-Ca, 59,60,61-Sc, 62,63-Ti, 65,66-V, 68-Cr, 70-Mn). The enhanced cross sections of several new nuclei relative to a simple thermal evaporation framework, previously shown to describe similar production cross sections, indicates that nuclei in the region around 62-Ti might be more stable than predicted by current mass models and could be an indication of a new island of inversion similar to that centered on 31-Na.Comment: 4 pages, 3 figures, to be published in Physical Review Letters, 200

Production cross sections of neutron rich isotopes from a 82Se beam

Production cross sections for neutron-rich nuclei from the fragmentation of a 82Se beam at 139 MeV/u were measured. The longitudinal momentum distributions of 122 neutron-rich isotopes of elements $11 \le Z \le 32$ were determined by varying the target thickness. Production cross sections with beryllium and tungsten targets were determined for a large number of nuclei including several isotopes first observed in this work. These are the most neutron-rich nuclides of the elements $22 \le Z \le 25$ (64Ti, 67V, 69Cr, 72Mn). One event was registered consistent with 70Cr, and another one with 75Fe. A one-body Qg systematics is used to describe the production cross sections based on thermal evaporation from excited prefragments. The current results confirm those of our previous experiment with a 76Ge beam: enhanced production cross sections for neutron-rich fragments near Z=20.Comment: Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS