Birds can transition between stable and unstable states via wing morphing.

Birds morph their wing shape to accomplish extraordinary manoeuvres1-4, which are governed by avian-specific equations of motion. Solving these equations requires information about a bird's aerodynamic and inertial characteristics5. Avian flight research to date has focused on resolving aerodynamic features, whereas inertial properties including centre of gravity and moment of inertia are seldom addressed. Here we use an analytical method to determine the inertial characteristics of 22 species across the full range of elbow and wrist flexion and extension. We find that wing morphing allows birds to substantially change their roll and yaw inertia but has a minimal effect on the position of the centre of gravity. With the addition of inertial characteristics, we derived a novel metric of pitch agility and estimated the static pitch stability, revealing that the agility and static margin ranges are reduced as body mass increases. These results provide quantitative evidence that evolution selects for both stable and unstable flight, in contrast to the prevailing narrative that birds are evolving away from stability6. This comprehensive analysis of avian inertial characteristics provides the key features required to establish a theoretical model of avian manoeuvrability.

Associations of Long-Term Tea Consumption with Depressive and Anxiety Symptoms in Community-Living Elderly: Findings from the Diet and Healthy Aging Study.

OBJECTIVE: To examine the association between long-term tea consumption and depressive and anxiety symptoms in community-living elderly. DESIGN: Community based cross-sectional study. SETTING: The Diet and Healthy Aging Study (DaHA), a prospective cohort study in Singapore. PARTICIPANTS: 614 elderly aged 60 years and above, who were free of dementia and cognitive impairment. MEASUREMENTS: Information on tea consumption was obtained through interviewer-administered questionnaire. Long-term tea drinking was defined as regular consumption for at least 15 years. Depressive and anxiety symptoms were measured using the 15-item Geriatric Depression Scale (GDS-15) and the 20-item Geriatric Anxiety Inventory (GAI), respectively. A generalized structural equation model (gSEM) was applied to ascertain the association between long-term tea consumption and depressive and anxiety symptoms. RESULTS: About 59% of the subjects had consumed tea for over 15 years. Long term tea consumption was significantly associated with a reduced odds of having depressive and anxiety symptoms, after adjusting for demographics (i.e., age, gender, education and ethnicity), comorbid conditions (i.e., heart disease, diabetes, stroke, hypertension and hyperlipidaemia) and long-term coffee consumption. CONCLUSION: There was evidence suggesting that long-term tea consumption was associated with reduced depressive and anxiety symptoms among community-living elderly. This suggests that it is worthwhile to further investigate the role of tea's bioactive compounds in promoting mental health in aging.

Association between Fish Intake and Depressive Symptoms among Community-living Older Chinese Adults in Singapore: A Cross-sectional Study.

OBJECTIVE: Our aim of this study was to investigate the association between fish consumption and depressive symptoms in senior ethnic Chinese residents of Singapore. DESIGN: A population-based cross-sectional study. SETTING: The Singapore Longitudinal Aging Studies (SLAS). PARTICIPANT: The study consisted of 2,034 participants from the Singapore Longitudinal Aging Studies (SLAS) project who were at least 55 years old. MEASUREMENTS: The presence of depressive symptoms was compared between those who self-reported eating fish at least three times a week versus those who ate fish less often. A score of 5 or greater on the 15-item Geriatric Depression Scale (GDS-15) was the cutoff for being designated as having depressive symptoms. RESULTS: Fish intake was associated with a lower prevalence of depressive symptoms ([odds ratio] OR = 0.60, 95% [confidence interval] CI 0.40-0.90; P = .015) after controlling for age, sex, marital status, housing, smoking, alcohol consumption, physical exercise, social and productive activities, self-rated health, hypertension, diabetes, heart failure or attack, stroke, fruit and vegetable intake, and Mini-Mental State Examination (MMSE) scores. CONCLUSION: Our results suggest that eating fish at least three times a week is associated with a lower odds of having depressive symptoms among Chinese adults over 55 years old living in Singapore.

Small field of view cone beam CT temporomandibular joint imaging dosimetry.

OBJECTIVES: Cone beam CT (CBCT) is generally accepted as the imaging modality of choice for visualisation of the osseous structures of the temporomandibular joint (TMJ). The purpose of this study was to compare the radiation dose of a protocol for CBCT TMJ imaging using a large field of view Hitachi CB MercuRay™ unit (Hitachi Medical Systems, Tokyo, Japan) with an alternative approach that utilizes two CBCT acquisitions of the right and left TMJs using the Kodak 9000(®) 3D system (Carestream, Rochester, NY). METHODS: 25 optically stimulated luminescence dosemeters were placed in various locations of an anthropomorphic RANDO(®) Man phantom (Alderson Research Laboratories, Stanford, CT). Dosimetric measurements were performed for each technique, and effective doses were calculated using the 2007 International Commission on Radiological Protection tissue weighting factor recommendations for all protocols. RESULTS: The radiation effective dose for the CB MercuRay technique was 223.6 ± 1.1 µSv compared with 9.7 ± 0.1 µSv (child), 13.5 ± 0.9 µSv (adolescent/small adult) and 20.5 ± 1.3 µSv (adult) for the bilateral Kodak acquisitions. CONCLUSIONS: Acquisitions of individual right and left TMJ volumes using the Kodak 9000 3D CBCT imaging system resulted in a more than ten-fold reduction in the effective dose compared with the larger single field acquisition with the Hitachi CB MercuRay. This decrease is made even more significant when lower tube potential and tube current settings are used.