14 research outputs found
Biochemical Differentiation in Japanese Newts, Genus Cynops (Salamandridae)
Genetic variation was surveyed in 38 populations of Japanese newts of the genus Cynops using starch gel eletrophoresis. C. ensicauda from the Ryuku Archipelago was shown to be genetically well differentiated from C. pyrrhogaster from the Japanese main islands. Separation of these two forms at the species level is supported. C. ensicauda is genetically divided into two groups, each of which corresponds to previously recognized subspecies. On the contrary, protein variation patterns in C. pyrrhogaster are not consistent with the previously recognized subspecies or local races. From available geological information, the electrophoretic clock is calibrated at 1D = 13-22 MY in Japanese Cynops
Local population differentiation in Hynobius retardatus from Hokkaido : an electrophoretic analysis (Caudata : Hynobiidae)
Allozyme data are used to examine the genetic relationships among two samples of Hynobius retardatus from Obihiro, and a geographically discrete sample from Chitose. The two samples from Obihiro are morphologically distinct from each other, but are found to be electrophoretically closely related, together forming a group distinct from the Chitose sample. The degree of genetic differentiation as measured by the F statistics is also low between the two Obihiro samples. The morphological differentiation seen between these two samples does not seem to be attributable directly to their genetic differentiation, but to the ecological divergence that is yet to be surveyed
Whole outline scanning measurement of internal gear by using CNC gear measuring machine
A three-dimensional probe is mounted on a specialized gear measuring machine whose measurement target is limited on the working flanks. The newly developed measuring machine has a coordinate measuring mechanism, aiming to be a highly versatile and relatively inexpensive measuring machine. According to our previous research, in addition to the working tooth surface, shape data of the root, bottom and tip profiles can be acquired with a single measurement operation. However, the target object for which this developed method has been applied was only the external cylindrical gear. In this paper, we applied and expanded the development method to the internal cylindrical gear and the evaluation of the axial displacement in the same cross-sectional scanning of the internal helical gear are performed
Lead exposure in raptors from Japan and source identification using Pb stable isotope ratios
Lead (Pb) poisoning is widespread among raptors and water birds. In Japan, fragments of Pb ammunition are still found in endangered eagles although more than 10 years have passed since legislation regarding use of Pb ammunition was introduced. This study was performed to investigate Pb exposure in raptors from various locations in Japan. We measured hepatic and renal Pb concentrations and hepatic Pb isotope ratios of Steller's sea eagles (Haliaeetus pelagicus), white-tailed sea eagles (Haliaeetus albicilla), golden eagles (Aquila chrysaetos), and 13 other species (total 177 individuals) that were found dead, as well as blood samples from three eagles found in a weakened state during 1993-2015 from Hokkaido (northern part), Honshu (the main island), and Shikoku (a southern island) of japan. In the present study in Hokkaido, one quarter of the sea eagles showed a high Pb concentration, suggesting exposure to abnormally high Pb levels and Pb poisoning. Pb isotope ratios indicated that endangered Steller's sea eagle and white-tailed sea eagle were poisoned by Pb ammunition that was used illegally in Hokkaido. In other areas of Japan, both surveillance and regulations were less extensive than in Hokkaido, but Pb poisoning in raptors was also noted. Therefore, Pb poisoning is still a serious problem in raptors in various areas of Japan due to accidental ingestion of materials containing Pb, especially Pb ammunition. (C) 2017 Published by Elsevier Ltd