Seasonal alternation of the ontogenetic development of the moon jellyfish Aurelia coerulea in Maizuru Bay, Japan.

Outbreaks of moon jellyfish Aurelia spp. are frequently reported from many parts of the world's coastal areas. Aurelia spp. canonically show a metagenetic life cycle in which planulae transform into sessile polyps, which can drastically increase in number through asexual reproduction. Therefore, their asexual reproduction has been recognized as one of the major causes of the outbreaks. Aurelia spp. also show direct development that lacks asexual reproduction during the polyp stage, which prevents us from understanding the mechanisms of its outbreaks. To clarify the seasonality of the metagenetic and direct-development life cycles of Aurelia sp. in Maizuru Bay, Japan, we conducted field observations and laboratory experiments throughout the year. Additionally, the two life cycle types were genetically analyzed to confirm that they belong to the single species Aurelia coerulea, which dominates in coastal waters in Japan. From July until October, Aurelia coerulea produced smaller eggs and planulae all of which developed into polyps. However, from December until May, larger eggs and planulae were produced and 90% of the planulae developed into planktonic ephyrae bypassing the sessile polyp stage. Our results demonstrated that a single species, A. coerulea, seasonally shifts between their two life cycle types at a water temperature threshold of 20°C in Maizuru Bay. The higher energy storage of larger planulae was suggested to enable the planulae to develop into ephyrae without external energy input through feeding during the polyp stage. The adaptive significances of the two life cycle types were also discussed.

Efficacy of continuous follow-up for preventing the involuntary readmission of psychiatric patients in Japan: a retrospective cohort study.

BACKGROUND: Providing aftercare to psychiatric inpatients is important for preventing frequent readmissions; however, the lack of social resources is a problem in Japan. The prefectural Tama-Fuchu Public Health Centre has attempted to establish a new continuous follow-up system for all discharged psychiatric patients in order to reduce the frequency of readmissions. AIMS: This study aims to evaluate the efficacy of this system. METHODS: The subjects of the present study were 200 psychiatric inpatients from the Tokyo catchment area. The continuous follow-up system was applied to 130 subjects for one year in addition to conventional standard care (the intervention group). Seventy subjects received conventional care alone (the comparison group). The incident rate ratios (IRR) of total and involuntary readmission to hospital were compared by survival analysis. RESULTS: During the observation period, there were 41 readmissions and 29 involuntary readmissions in 49,731 person-days. The patients subjected to continuous follow-up showed a trend towards a lower overall risk of readmission (IRR = 0.56, 95% CI: 0.29-1.10, p = .057) and a significantly reduced risk of involuntary admission (IRR = 0.48, 95% CI: 0.22-0.96, p = .047). CONCLUSION: This study provides empirical evidence that providing continuous follow-up examinations as aftercare for discharged psychiatric patients significantly reduces the incidence of involuntary readmission.