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The nanodomain pattern in ferroelectric/dielectric superlattices transforms to a uniform polarization state under above-bandgap optical excitation. X-ray scattering reveals a disappearance of domain diffuse scattering and an expansion of the lattice. The reappearance of the domain pattern occurs over a period of seconds at room temperature, suggesting a transformation mechanism in which charge carriers in long-lived trap states screen the depolarization field. A Landau-Ginzburg-Devonshire model predicts changes in lattice parameter and a critical carrier concentration for the transformation.

The Caribbean share of the global tourism market has been declining. This study examines what is driving tourism flows. It estimates the determinants of tourism and explores variations based on sample differences, and also constructs a static nominal price comparison index. The paper finds that: (i) tourism arrivals and expenditure are sensitive to both price and income factors in source markets; (ii) price and income elasticities of tourism have declined since 2008; (iii) price elasticity is statistically insignificant for "high-end" destinations; and (iv) the nominal cost of an average one week beach holiday in the Caribbean is higher than in other beach destinations around the world. These results point to the need for structural reforms to raise product quality, cost reduction or containment in "low-end" destinations, including possibly via exchange rates, and an adjustment in aggregate consumption to adapt to the implications of a lower contribution to GDP from tourism.

Quantum devices formed in high-electron-mobility semiconductor heterostructures provide a route through which quantum mechanical effects can be exploited on length scales accessible to lithography and integrated electronics. The electrostatic definition of quantum dots in semiconductor heterostructure devices intrinsically involves the lithographic fabrication of intricate patterns of metallic electrodes. The formation of metal/semiconductor interfaces, growth processes associated with polycrystalline metallic layers, and differential thermal expansion produce elastic distortion in the active areas of quantum devices. Understanding and controlling these distortions present a significant challenge in quantum device development. We report synchrotron X-ray nanodiffraction measurements combined with dynamical X-ray diffraction modeling that reveal lattice tilts with a depth-averaged value up to 0.04° and strain on the order of 10 in the two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure. Elastic distortions in GaAs/AlGaAs heterostructures modify the potential energy landscape in the 2DEG due to the generation of a deformation potential and an electric field through the piezoelectric effect. The stress induced by metal electrodes directly impacts the ability to control the positions of the potential minima where quantum dots form and the coupling between neighboring quantum dots.

Although a number of methods using scanning probe lithography to pattern graphene have already been introduced, the fabrication of real devices still faces limitations. We report graphite patterning using scanning probe lithography with control of the gas environment. Patterning processes using scanning probe lithography of graphite or graphene are normally performed in air because water molecules forming the meniscus between the tip and the sample mediate the etching reaction. This water meniscus, however, may prevent uniform patterning due to its strong surface tension or large contact angle on surfaces. To investigate this side effect of water, our experiment was performed in a chamber where the gas environment was controlled with methyl alcohol, oxygen or isopropanol gases. We found that methyl alcohol facilitates graphite etching, and a line width as narrow as 3 nm was achieved as methyl alcohol also contains an oxygen atom which gives rise to the required oxidation. Due to its low surface tension and highly adsorptive behavior, methyl alcohol has advantages for a narrow line width and high speed etching conditions.

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Financial sector linkages have increased continuously in the Caribbean with cross border capital flows and financial conglomerates dominating the financial system. While the greater interconnectedness can heighten systemic risks and likelihood of contagion, it can have positive impacts provided the regional authorities take steps to prevent the systemic risk. In this context, financial sector reform measures aimed at bolstering and harmonizing prudential regulations in line with international best practices, the strengthening and enhancement of financial sector supervision to include cross border linkages through consolidated supervision, increased cooperation across supervisors in the region, and the establishment of deposit insurance and crisis resolution frameworks will be critical to maintain financial sector stability and minimize the repercussions of any negative shocks.

The recent global financial crisis has significantly affected sovereign wealth funds' (SWFs') financial performance and their investment activities. The crisis shed a new light on SWFs' objectives and priorities. SWFs need to review critically their strategic asset allocation (SAA) within a sovereign asset and liability management (ALM) framework, and their assets should be analyzed over complete economic cycles including market turbulences. The crisis raises also the question of whether some of the underlying objectives of the Santiago Principles-maintaining a stable global financial system and maximizing financial returns-are perhaps conflicting. We argue that any conflict was from a wrong interpretation of the principles, not from the principles themselves. Ultimately, stable financial markets are in each SWF's self interest, also from a narrow financial perspective. In this respect, financial stability and financial risk ⁄ return can be mutually reinforcing objectives rather than conflicting.