Chaetognaths are ubiquitous in the marine environment and are among the most abundant carnivorous plankton. Nevertheless, characterization of physiological parameters remains limited largely due to the difficulty in obtaining the data from pelagic chaetognaths in laboratory studies. This study therefore aimed to determine the feeding and growth rates of Zonosagitta nagae under laboratory rearing condition. A total of 54 field-collected chaetognaths with maturity Stage I and II ranging from 5 to 12 mm in body length collected in June, August and October were individually incubated at 20–22°C with excess copepod prey and growth parameters were obtained from 26 individuals that survived ~10–46 days. For Z. nagae, ingestion and growth rates increased with body dry weight, and both parameters were significantly related, indicating that gross growth efficiency was ~47%. Specific ingestion rates ranged from 0.03 to 0.43 d−1 and tended to decrease with an increase of size of the chaetognaths. Individual specific growth rate varied widely in small-sized individuals (~6 mm), ranging from −0.103 to 0.135, but became relatively constant (~0.032) with increasing size. Overall the study results suggest that Z. nagae is characterized by high gross growth efficiency, which is in striking contrast with previously studied inshore species.

Digestion time and feeding of the pelagic chaetognath Zonosagitta nagae, which occurs predominantly in warm waters around Japan, were investigated in the laboratory. Young individuals of Z. nagae ranging from 4.1-7.6 mm in body length were used for the experiments with adult females of the copepod Acartia steueri as prey. The mean digestion time of Z. nagae was 115±3 minutes at 20°C. Temporal change in individual s feeding intensity was observed every 1.5 h for 24 h to determine the diel feeding pattern, feeding interval, feeding rates and daily ration. Almost all individuals showed no clear diel rhythm within 24-h at 20°C under 12L:12D cycle; time interval between feeding was 4.5-6 h (mode) for individuals that ingested multiple copepods. The number of copepods ingested by a chaetognath ranged from 0 to 5 and on average 2.6 copepods were consumed a day per individual. Specific daily ration in most individuals corresponded to ca. 50% of its dry weight while some individuals showed the extremes of non-feeding or voracious feeding (>200% d −1), indicating that some of the young Z. nagae had an intermittent feeding mode, which would be adaptive to save energy expenditure at low prey densities and to reduce mortality by lowering the risk of predation.

Objectives: This study aimed to clarify the effect of an intervention using a head-mounted display with a web camera set at a modified pitch angle on spatial awareness, sit-to-stand movement, and standing balance in patients with left and right hemisphere damage. Methods: The participants were 12 patients with right hemisphere damage and 12 patients with left hemisphere damage. The line bisection test, a sit-to-stand movement, and balance assessment were performed before and after the intervention. The intervention task involved pointing at targets 48 times in an upward bias condition. Results: Significant upward deviation on the line bisection test was noted in patients with right hemisphere damage. The load on the forefoot during the sit-to-stand movement was significantly increased. The range of anterior–posterior sway during forward movement in the balance assessment was reduced. Conclusions: An adaptation task performed in an upward bias condition may produce an immediate effect on upward localization, sit-to-stand movement, and balance performance in patients with right hemisphere stroke.