Animal stress is influenced by environmental factors, yet only a few studies have evaluated the effects of environmental stress on captive dogs. This study aimed to evaluate the effects of environmental and social enrichment on the stress levels of captive dogs housed in a lab. We assessed stress levels in eight Beagle dogs by measuring their body weight, cortisol levels, a stress hormone, the alkaline phosphatase activity in serum, the number of steps per hour, as well as clinical sign observations in a changed environment for 6 weeks. Four dogs assigned to a control group were raised alone in a relatively narrow place without toys; four dogs assigned to an experimental group were raised together in a relatively large place with toys. The body weight of the control group remained unchanged, while that of the experimental group decreased. Cortisol levels in the control group increased throughout, whereas those in the experimental group increased for up to 2 weeks and decreased thereafter. Consequently, cortisol levels in the experimental group significantly decreased compared to the control group at 6 weeks (p = 0.048). Fighting was observed among the dogs in the experimental group at 3 weeks; thus, one dog was separated from the group. The number of steps per hour was more than twice as high in the experimental than in the control group. Thereby, we determined that social housing, with appropriate companions and environmental enrichment materials, can reduce stress levels in captive dogs more efficiently than in single housing without such materials. Our study provides useful insights for captive animal organizations, such as kenneled dogs’ management, to improve animal welfare.

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Track irregularities have a strong influence on the safety and the ride comfort of trains as well as track maintenance work. A statistical analysis was conducted for track irregularities data measured in Kyoungbu high speed line using a track recording car(EM120). First, the characteristics of EM120, which adopted versine measurement system, were investigated and the transfer function of EM120 was examined. The distributions of the surface and the alignment which have short wavelength were considerably high and the distribution decreased as wavelength increases. A distribution analysis of the wavelength was carried out according to EN standards and most of the track irregularities were in a D1 wavelength range. The distributions of the amplitude of track irregularities were also investigated and the results show that the distributions of track irregularities decrease rapidly as amplitude increases. These results may be helpful in making track maintenance plans and revising track irregularities criteria.

The reduction strategies of the track irregularity in the bridge expansion joint zone are an important issue in the ballasted track on the high speed railway bridge. In general, the track irregularity on the railway bridge occurs at the expansion joint zone and is more spread across the bridge. This is due to the dynamic behavior from the train-induced dynamic impact and thermal expansion of the bridge. In this paper, field testing of the several methods for reducing the track irregularity on the bridge expansion joint zone such as the zero longitudinal restraint(ZLR), tied sleeper and ballast stabilizer is conducted. And then the progress of the track irregularity and the frequency of the maintenance work before and after the filed test construction are investigated.