Surface Soil Effects Studies Based on HN Ratios of Microtremors at Kingston Metropolitan Area, Jamaica

The authors performed single mobile microtremor measurements at 218 sites at KMA （Kingston Metropolitan Area） with the objective of estimating the amplification effects due to the earthquake ground motion on the surface geology. The Fourier transform was applied to the most stationary parts of the triaxial wave motion recordings for each individual site and applied the traditional Nakamura technique, namely, the horizontal to vertical spectral ratio （H/V） to retrieve the predominant shear wave period of vibration of the soil profiles above the bedrock. The results yield predominant long periods of about 3.0-4.0 s in the port area and the waterfront, 1.0-2.0 s in the central part of Kingston, 0.3-1.0 s in Portmore and very stiff soil conditions in the surrounding area of the city. The results coincide fairly well with previous geological studies in the region, geotechnical data in boreholes, gravimetric measurements and strong motion recordings, suggesting a high degree of amplification of ground motion in the whole period range of engineering interest. Additionally, the authors obtained the liquefaction vulnerability factor Kg proposed by Nakamura based on the H/V ratio of microtremors. The results suggest that the port area, the waterfront and the Port Royal are highly susceptible to liquefaction. Finally, the authors obtained fundamental periods of vibration based on microtremor measurements on the roof and the basement of four important buildings in the KMA and indicated future lines of research employing ambient noise measurements on structures.     

Continuous spectrophotometric assay of conjugated bile acid hydrolase

Conjugated bile acid hydrolase (CBAH) refers to a class of enzymes which catalyze the cleavage of the amino acid moieties from conjugated bile acids. These enzymes are significant because of their role in providing substrates for further microbial metabolism in the gastrointestinal tract. They also are used in research laboratories for the deconjugation of bile acids prior to structural analyses. A continuous spectrophotometric assay for CBAH activity was developed using a conjugate of cholic acid and the chromophore, 5-amino-2-nitro-benzoic acid. The free chromophore is detected by virtue of its absorbance at 410 nm. The CBAH fromClostridium perfringens displayed aK _m for this substrate of 120 μM. These results demonstrate that this new compound functions as an effective substrate of the enzyme and forms the basis for a convenient and rapid method to monitor CBAH activity.     

UK government venture into standards

Standards in computing have long been talked about but little has happened. Microcomputing is little different and possibly worse. The government is now taking a lead and two computer compiler validation schemes are under development, COBOL at the NCC and Pascal at BSI. This white paper stresses the need for greater involvement and commitment by industry in standards making. The government appears ready to play its part. It is a great opportunity for anyone with a professional interest in computing to start making a real contribution. As good a means as any would be to study in detail this important white paper.     

Combinatorial photometric stereo and its application in 3D modeling of melanoma

This article concerns a new type of photometric stereo algorithm for which outliers such as highlights and shadows, including attached and cast shadow, are mixed with Lambertian data. The underlying motivation behind this algorithm is very simple: an axial symmetrical setup in 6-light photometric stereo can be used to offer advantages. We investigate why an axial symmetrical setup is useful and how it can be used to improve standard photometric stereo. The main result is summarized as a combinatorial photometric stereo algorithm which embeds a non-Lambertian detection procedure. To apply this algorithm, it involves three steps. First, it combines a group of reflectance intensities to make five virtual images, whose equivalence is guaranteed due to the axial symmetrical setup of the 6-source photometric stereo system. Second, comparison between these virtual images generates a five by five skew-symmetric matrix. The Frobenius norm of this matrix is then employed as an index to determine whether there is a non-Lambertian pixel present among the six pixels. Finally, after identification of non-Lambertian pixels, standard photometric stereo is performed to realize 3D modeling. Validation of this algorithm has been conducted with both synthetic and real images. The real images were obtained from a newly designed 3D imaging device, the Skin Analyzer, for clinical inspection of melanoma. Experimental study shows that combinatorial photometric stereo gives promising results in suppressing shadows and highlights, while improving 3D reconstruction results. Furthermore, error analysis illustrates how to determine an appropriate threshold value to enable the algorithm to achieve optimal performance.     

Atypical manifestation of upper lid margin staining in silicone hydrogel lens wearers with symptoms of dry eye.

PURPOSE: To report an atypical manifestation of upper lid margin staining (ULMS) that occurred in adapted silicone hydrogel (SH) contact lens wearers who complained of ocular surface dryness. METHODS: Sequential staining with sodium fluorescein (FL) and lissamine green (LG) strips was performed in 38 SH lens wearers. The "wiper area" of the upper lid was examined with the slit lamp, at 8x and 12x magnifications. RESULTS: Four out of 38 subjects (10.5%) showed fimbriated or "feathery" extensions from the superior margin of the subtarsal fold onto the upper tarsal plate. The extent of these feathery extensions varied between subjects, with a mean (+/-S.D.) length of 2+/-0.8 mm. In all cases a broad band of staining with both FL and LG was demonstrated, which extended along the entire length of the lid margin. CONCLUSION: The staining patterns shown on the subjects' upper lid margins and tarsal plates suggest that ULMS may include more complex variants. The putative tissue damage revealed through the staining, points to a mechanism not simply restricted to the upper lid margin.     

A Light‐Driven Microgel Rotor

The current understanding of motility through body shape deformation of micro‐organisms and the knowledge of fluid flows at the microscale provides ample examples for mimicry and design of soft microrobots. In this work, a 2D spiral is presented that is capable of rotating by non‐reciprocal curling deformations. The body of the microswimmer is a ribbon consisting of a thermoresponsive hydrogel bilayer with embedded plasmonic gold nanorods. Such a system allows fast local photothermal heating and nonreciprocal bending deformation of the hydrogel bilayer under nonequilibrium conditions. It is shown that the spiral acts as a spring capable of large deformations thanks to its low stiffness, which is tunable by the swelling degree of the hydrogel and the temperature. Tethering the ribbon to a freely rotating microsphere enables rotational motion of the spiral by stroboscopic irradiation. The efficiency of the rotor is estimated using resistive force theory for Stokes flow. This research demonstrates microscopic locomotion by the shape change of a spiral and may find applications in the field of microfluidics, or soft microrobotics.     

Retail Store Performance Model the Impact of Own-branch 'Friendly Fire'

Store location modelling is still far from accepted practice in most national retailers. A growing number, however, are implementing regression-based approaches. While as a statistical technique, regression is far from innovative, its gradual acceptance in retailing is bringing welcome benefits to many companies. Implementation, though, requires careful planning. Recent developments have concentrated on incorporating competitive forces of two types. The impact on sales of competitors' brands and store networks. The fears of cannibalisation of sales as dense branch networks place a retailer's own stores in close proximity to each other — the impact of 'friendly fire'.