Management Response to the Tsunami, Surin Marine National Park, Thailand

Surin Marine National Park lies northwest of Phuket. Before the 26 December 2004 tsunami, its reputation as the best shallow-water reef in Thailand attracted more than 30000 visitors per year to the 8km2 of fringing reef. Visitor management included fees, permits, specific activities management, a zoning plan and an information centre. Zoning plan exclusion areas included the area of highest biodiversity and a coral bleached area (for natural recovery). While management faced many long-term challenges, it was generally appropriate for the visitation level and threats to the reef system. The tsunami demolished all park infrastructure and effectively destroyed the capacity to manage. Major tourist operators were reduced, currently, from four to two, although dive-boats were largely unaffected. The biodiverse exclusion area and the area most used for snorkelling (near the park headquarters) were destroyed. While tourist arrivals were decimated, rapid recovery is expected with associated demand to access unaffected sites. The problem for management is to re-establish an effective presence and define a regime that is supportive of tourism-recovery, but meets long-term conservation objectives. This paper documents pre and post tsunami reef condition, visitor and operator expectations of management and possible approaches to short and long term management

Comparison of predicted and actual over-refractions when using the Mastervue\u27s RGP fitting recommendations

The use of computerized corneal videokeratography is one of the most exciting advances in the fitting of rigid contact lenses today. Traditional RGP fitting methods and our understanding of physiological and contact lens optics dictates that power should be determined by comparing lens lens base curve to the central three millimeter zone flat keratometric reading, and apply SAMFAP to compensate for lacrimal lens effects. This study addresses the Issue that since the Mastervue lens fitting software selects lens base curve determined using a more peripheral corneal zone, clinically, how and where should lens power be determined? Twenty-eight subjects were fit with rigid gas permeable lenses generated by the Mastervue corneal topographer fitting software. Accurate monocular over-refractions were performed and compared to the predicted over-refractions determined using the simulated keratometric values at each the three millimeter and six millimeter corneal zones. From this data it can be shown which simulated keratometric readings should be used to determine the clinically most accurate contact lens power. The data showed that it did not matter which corneal zone SAMFAP is applied to when determining contact lens power. Through the interpretation of these results, it can be deduced that the Mastervue fitting software is effective in suggesting an initial RGP to be dispensed, however, trial fitting with an over-refraction is still the most accurate way of determining final lens power

Photochemistry of glycolaldehyde in cryogenic matrices

International audienceThe photochemistry of glycolaldehyde (GA) upon irradiation at 266 nm is investigated in argon, nitrogen, neon, and para-hydrogen matrices by IR spectroscopy. Isomerization and fragmentation processes are found to compete. The hydrogen-bonded Cis-Cis form of GA is transformed mainly to the open Trans-Trans conformer and to CO and CH3OH fragments and their mixed complexes. Different photo-induced behaviours appear depending on the matrix. In nitrogen, small amounts of Trans-Gauche and Trans-Trans conformers are detected after deposition and grow together upon irradiation. The Trans-Gauche conformer is characterized for the first time. In para-hydrogen due to a weaker cage effect additional H2CO and HCO fragments are seen. Calculations of the potential energy surfaces of S0, S1, and T1 states – to analyse the torsional deformations which are involved in the isomerization process – and a kinetic analysis are presented to investigate the different relaxation pathways of GA. Fragmentation of GA under UV irradiation through the CO+CH3OH molecular channel is a minor process, as in the gas phase

Deterministic nano-assembly of a coupled quantum emitter - photonic crystal cavity system

The interaction of a single quantum emitter with its environment is a central theme in quantum optics. When placed in highly confined optical fields, such as those created in optical cavities or plasmonic structures, the optical properties of the emitter can change drastically. In particular, photonic crystal (PC) cavities show high quality factors combined with an extremely small mode volume. Efficiently coupling a single quantum emitter to a PC cavity is challenging because of the required positioning accuracy. Here, we demonstrate deterministic coupling of single Nitrogen-Vacancy (NV) centers to high-quality gallium phosphide PC cavities, by deterministically positioning their 50 nm-sized host nanocrystals into the cavity mode maximum with few-nanometer accuracy. The coupling results in a 25-fold enhancement of NV center emission at the cavity wavelength. With this technique, the NV center photoluminescence spectrum can be reshaped allowing for efficient generation of coherent photons, providing new opportunities for quantum science.Comment: 13 pages, 4 figure

The Slowly Formed Guiselin Brush

We study polymer layers formed by irreversible adsorption from a polymer melt. Our theory describes an experiment which is a ``slow'' version of that proposed by Guiselin [Europhys. Lett., v. 17 (1992) p. 225] who considered instantaneously irreversibly adsorbing chains and predicted a universal density profile of the layer after swelling with solvent to produce the ``Guiselin brush.'' Here we ask what happens when adsorption is not instantaneous. The classic example is chemisorption. In this case the brush is formed slowly and the final structure depends on the experiment's duration, $t_{final}$. We find the swollen layer consists of an inner region of thickness $z^* \sim t_{final}^{-5/3}$ with approximately constant density and an outer region extending up to height $h \sim N^{5/6}$ which has the same density decay $\sim z^{-2/5}$ as for the Guiselin case.Comment: 7 pages, submitted to Europhysics Letter