GCA: Better ✓check for third cranial nerve involvement!

Key Points • The intriguing “Check Mark Sign” suggests 3rd cranial nerve involvement in GCA.

Atypical correlation of otolith strontium : calcium and barium : calcium across a marine–freshwater life history transition of a diadromous fish

Variation in strontium (Sr) and barium (Ba) within otoliths is invaluable to studies of fish diadromy. Typically, otolith Sr:Ca is positively related to salinity, and the ratios of Ba and Sr to calcium (Ca) vary in opposite directions in relation to salinity. In this study of jungle perch, Kuhlia rupestris, otolith Sr:Ca and Ba:Ca, however, showed the same rapid increase as late-larval stages transitioned directly from a marine to freshwater environment. This transition was indicated by a microstructural check mark on otoliths at 35–45 days age. As expected ambient Sr was lower in the fresh than the marine water, however, low Ca levels (0.4mgL–1) of the freshwater resulted in the Sr:Ca being substantially higher than the marine water. Importantly, the otolith Sr:Ba ratio showed the expected pattern of a decrease from the marine to freshwater stage, illustrating that Sr:Ba provided a more reliable inference of diadromous behaviour based on prior expectations of their relationship to salinity, than did Sr:Ca. The results demonstrate that Ca variation in freshwaters can potentially be an important influence on otolith element:Ca ratios and that inferences of marine–freshwater habitat use from otolith Sr:Ca alone can be problematic without an understanding of water chemistry.

Aerodynamic Investigation of Air Knife System to Find Out the Mechanism of the Check Mark in a Continuous Hot-Dip Galvanizing Process

When galvanized steel strip is produced through a continuous hot-dip galvanizing process, the thickness of the adhered zinc film is controlled by a gas wiping process. In the gas wiping process there is a technically serious problem which is called a “check mark problem”. The check mark is caused by non-uniform coating on the steel strip surface. Such a non-uniform zinc coating lowers the quality, productivity and profit of the end products. In the present study, to find out the causes of the check mark and technical methods to resolve the check mark problem, the flow field of the high speed rectangular nitrogen gas jet which is impinging on the moving steel strip in the continuous hot-dip galvanizing system has been investigated numerically by using a commercial 3-D flow analysis code, FLUENT. LES (Large Eddy Simulation) is used to obtain instantaneous flow field in the region under consideration. Numerical studies were conducted for two ratios of the plate distance (d) to the nozzle width (x) d/x = 6.7, 10.5 under the same jet Reynolds number of Re = 20000. It was found that the check mark is caused by the alternating vortices which are generated on the jet impinging line (stagnation line). The center of the alternating vortex has a relatively low pressure compared with the periphery of the vortex. The high impinging pressure removes the adhered molten zinc more than the low pressure. Hence the non-uniformity of the zinc coating appears on the strip surface. Such the alternating vortices move periodically to the right and to the left sides on the impinging line due to the jet flow instability and the pressure force balance. In addition since the strip moves upward at a constant speed, the non-uniform coating results in a variety of patterns like “W”, “V” and “X”. This pattern is collectively called as “check mark” in the production field. The angle of the check mark was calculated by using both the moving speeds of the steel strip and the vortices. It was favorably compared with the experimental measurement.