As an alternative to correlation-based techniques widely used in conventional speckle metrology, we propose a new technique that makes use of phase singularities in the complex analytic signal of a speckle pattern as indicators of local speckle displacements. The complex analytic signal is generated by vortex filtering the speckle pattern. Experimental results are presented that demonstrate the validity and the performance of the proposed optical vortex metrology with nano-scale resolution.

Dorsal closure in Drosophila embryogenesis involves expansion of the dorsal epidermis, followed by closure of the opposite epidermal edges. This process is driven by contractile force generated by an extraembryonic epithelium covering the yolk syncytium known as the amnioserosa. The secreted signaling molecule Dpp is expressed in the leading edge of the dorsal epidermis and is essential for dorsal closure. We found that the outermost row of amnioserosa cells (termed pAS) maintains a tight basolateral cell-cell adhesion interface with the leading edge of dorsal epidermis throughout the dorsal closure process. pAS was subject to altered cell motility in response to Dpp emanating from the dorsal epidermis, and this response was essential for dorsal closure. alphaPS3 and betaPS integrin subunits accumulated in the interface between pAS and dorsal epidermis, and were both required for dorsal closure. Looking at alphaPS3, type I Dpp receptor, and JNK mutants, we found that pAS cell motility was altered and pAS and dorsal epidermis adhesion failed under the mechanical stress of dorsal closure, suggesting that a Dpp-mediated mechanism connects the squamous pAS to the columnar dorsal epidermis to form a single coherent epithelial layer.

[1] Temporal variations of carbon monoxide (CO) were observed simultaneously at seven surface stations located in east Asia/western North Pacific from 24°N to 43°N during the East Asian Regional Experiment (EAREX) 2005 campaign in March 2005. Three major pollution events with enhanced CO levels were recorded around the same time at four stations over the East China Sea and at two northern stations of Japan. These pollution events were also observed 3-4 d later at Minamitorishima, located far from the Asian continent. A synoptic weather analysis showed that all of the major CO enhancements were brought about by the passages of cold fronts associated with the eastward migrating cyclonic development. The CO distribution simulated by a three-dimensional transport model showed that the polluted air masses exported from the continent were trapped behind the cold fronts and then merged into elongated belts of enriched CO before spreading over the western North Pacific. Transport of regionally tagged CO tracer simulated by the model indicated that the Chinese and Korean emissions were the major contributors to the pollution over the East China Sea, while the Japanese emissions had impacts at relatively higher latitude regions during the campaign. The simulation results also showed that the CO enhancements detected at Minamitorishima were caused by a long-range transport of pollution emissions from various regions in east Asia. The CO-enriched plumes from Southeast Asia and south Asia emissions were found above the boundary layer in the frontal zone but not at the surface.

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A new automated 222 Rn measuring system suitable for a wide range of atmospheric observations has been developed. This system comprises a 222 Rn analyzer and an air-sampling unit, along with a pump, drying equipment, and a filter. The operation of this 222 Rn analyzer is based on an electrostatic collection method involving the use of a PIN photodiode to separately detect a particles emitted from 218 Po and 214 Po released from the decay of 222 Rn in a hemispheric air-sample chamber. The response of the 222 Rn analyzer with respect to the applied voltage, chamber volume size, and sample flow rate is investigated to determine the appropriate measuring conditions. With this instrument, the detection limits have improved to 0.16-0.20 Bq m À3 for 1 h. The new 222 Rn analyzer shows several technical advancements over the previous electrostatic collection methods, such as an improved detection limit, higher sensitivity, higher time-resolution analysis, and longer life. During the preliminary observational test, the 222 Rn measuring system was able to detect the diurnal cycle in 222 Rn resulting from the mixing of rapid vertical air in the surface boundary layer. At the Minamitorishima station located far from the continent, very small 222 Rn peaks were clearly detected when long-range transport of polluted air masses from the Asian continent was observed at the station. We demonstrate that our compact 222 Rn measuring system has the potential to be widely used for high time-resolution measurements of low-level 222 Rn.