Echolocation call production during aerial and terrestrial locomotion by New Zealand's enigmatic lesser short-tailed bat, Mystacina tuberculata

Linkage of echolocation call production with contraction of flight muscles has been suggested to reduce the energetic cost of flight with echolocation, such that the overall cost is approximately equal to that of flight alone. However, the pattern of call production with limb movement in terrestrially agile bats has never been investigated. We used synchronised high-speed video and audio recordings to determine patterns of association between echolocation call production and limb motion by Mystacina tuberculata Gray 1843 as individuals walked and flew, respectively. Results showed that there was no apparent linkage between call production and limb motion when bats walked. When in flight, two calls were produced per wingbeat, late in the downstroke and early in the upstroke. When bats walked, calls were produced at a higher rate, but at a slightly lower intensity, compared with bats in flight. These results suggest that M. tuberculata do not attempt to reduce the cost of terrestrial locomotion and call production through biomechanical linkage. They also suggest that the pattern of linkage seen when bats are in flight is not universal and that energetic savings cannot necessarily be explained by contraction of muscles associated with the downstroke alone.

Depressive symptoms and adverse outcomes from hospitalization in older adults : secondary outcomes of a trial of falls prevention education

Depression is common in older people and symptoms of depression are known to substantially increase during hospitalization. There is little known about predictors of depressive symptoms in older adults or impact of common interventions during hospitalization. This study aimed to describe the magnitude of depressive symptoms, shift of depressive symptoms and the impact of the symptoms of depression among older hospital patients during hospital admission and identify whether exposure to falls prevention education affected symptoms of depression. Participants (n = 1206) were older adults admitted within two Australian hospitals, the majority of participants completed the Geriatric Depression Scale – Short Form (GDS) at admission (n = 1168). Participants’ mean age was 74.7 (±SD 11) years and 47% (n = 551) were male. At admission 53% (619 out of 1168) of participants had symptoms of clinical depression and symptoms remained at the same level at discharge for 55% (543 out of 987). Those exposed to the low intensity education program had higher GDS scores at discharge than those in the control group (low intensity vs control n = 652, adjusted regression coefficient (95% CI) = 0.24 (0.02, 0.45), p = 0.03). The only factor other than admission level of depression that affected depressive symptoms change was if the participant was worried about falling. Older patients frequently present with symptoms of clinical depression on admission to hospital. Future research should consider these factors, whether these are modifiable and whether treatment may influence outcomes.