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Morphological differentiation in giant salamanders, Andrias japonicus, A. davidianus, and their hybrids (Urodela, Cryptobranchidae), and its taxonomic implications.

For a long time, it has been debated whether the two giant salamanders, Andrias japonicus from Japan and A. davidianus from China, are conspecific or heterospecific. Morphological information about their diagnostic characteristics has been limited, without considering sexual dimorphism and/or body size variation. Recently, A. davidianus, which was introduced into Japan sometime in the past, has been found to hybridize with A. japonicus in situ. Taxonomic identification of individuals involved in this unusual breeding is made based on mitochondrial and nuclear DNA analyses. This identification method is time-consuming and costly. Thus, developing easier methods of identification, such as utilizing external morphological characteristics, is urgently needed. In this study, we verify previous descriptions showing that A. davidianus has a longer relative tail length than A. japonicus, and the tubercles on the lower jaw and throat were present in both sexes of A. davidianus. In addition, many head characteristics were found to be relatively larger in A. davidianus than in A. japonicus, which were new distinguishing characters. These morphological differences help support the idea that these are heterospecific lineages. In hybrids, relative values of head width and tail length were larger than those of A. japonicus, and the tubercles on their lower jaw and throat were present as in A. davidianus, suggesting that the hybrids and A. davidianus are distinguishable from A. japonicus.

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A cross sectional study of role of health literacy on the differences in health behaviors between shift workers and day workers

Abstract Background Shift work is a common working style in the manufacturing industry. Many studies have reported that shift workers have unfavorable health behaviors. To investigate using a cross-sectional study whether health literacy had a mediating influence on the differences in health behaviors between the shift workers and day workers. Methods The target population was employees in a light metal product manufacturing company in Japan. In 2020, we conducted a survey on job characteristics, health literacy, and health behaviors using a self-administered questionnaire. A total of 2152 manual workers aged between 18-64 years were enrolled in the study (961 fixed day and 1191 shift workers). The odds ratios for favorable habits in shift workers relative to those in daytime workers were calculated using multivariate logistic regression analysis. Logistic regression structural equation models were used to analyze the mediating role of health literacy on the relationship between shift work and health behaviors. Results The odds ratios (95% confidence interval) of shift workers, with daytime workers as the reference group, following adjustment for age, health literacy, educational attainment, marital status, and working hours were 0.85 (95%CI, 0.70-1.02) for performing leisure time exercise, 0.68 (95%CI, 0.56-0.80) for not currently smoking, 0.63 (95%CI, 0.52-0.76) for brushing their teeth, 0.79 (95%CI, 0.65-0.95) for having breakfast, and 0.58 (95%CI, 0.48-0.70) for eating green and yellow vegetables. With the exception of smoking, health literacy was associated with health behaviors independent of job characteristics. The odds ratios of the direct effects of shift work on favorable habits were almost the same as the total effect. Conclusions Health literacy did not have a mediating influence on the association between the shift work and health behaviors in manual workers. Both job characteristics and Health literacy were related independently with health behaviors in the workers. Our findings suggest that in order to improve health behaviors in workers, both improvement in the working environment and efforts to improve Health literacy are required.

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Thermal self-similar disc winds: transonic nature

ABSTRACT Thermally driven two-dimensional disc winds are examined under the fully self-similar treatment, focusing the attention on the transonic nature. In the spherical potential, such as point-mass and logarithmic ones, the usual transonic solutions cannot be constructed, because the critical conditions themselves do not exist. That is, the flow can reach the sonic point in the polar direction, while there is no gravitational force in the polar direction, and the regularity condition does not hold. In the non-spherical potential, such as the Mestel self-gravitating one, the gravity works in the polar direction, and therefore, there are critical points in the flow. However, the usual transonic solutions do not exist, since the topology of the critical points is always centre (O-type). Hence, in the fully self-similar disc winds, the usual transonic solutions passing through the critical points do not exist, at least for typical cases. Instead, the new-type wind solutions are found in the point-mass case. In contrast to the usual transonic flows, the new-type solutions are continuously accelerated along the streamline by the thermal pressure, and eventually become supersonic in the streamline direction without passing through the critical points. These new-type solutions are possible, when the density distribution is centrally concentrated, and when the initial subsonic velocity is not so large to avoid singularities.

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