Effects of flight altitude on the lift generation of monarch butterflies: from sea level to overwintering mountain.

Aerodynamic efficiency behind the annual migration of monarch butterflies, the longest among insects, is an unsolved mystery. Monarchs migrate 4000 km at high-altitudes to their overwintering mountains in Central Mexico. The air is thinner at higher altitudes, yielding reduced aerodynamic drag and enhanced range. However, the lift is also expected to reduce in lower density conditions. To investigate the ability of monarchs to produce sufficient lift to fly in thinner air, we measured the climbing motion of freely flying monarchs in high-altitude conditions. An optical method was used to track the flapping wing and body motions inside a large pressure chamber. The air density inside the chamber was reduced to recreate the higher altitude densities. The lift coefficient generated by monarchs increased from 1.7 at the sea-level to 9.4 at 3000 m. The correlation between this increase and the flapping amplitude and frequency was insignificant. However, it strongly correlated to the effective angle of attack, which measures the wing to body velocity ratio. These results support the hypothesis that monarchs produce sufficiently high lift coefficients at high altitudes despite a lower dynamic pressure.

Outcomes after thrombus aspiration for ST elevation myocardial infarction: 1-year follow-up of the prospective randomised TOTAL trial

BackgroundTwo large trials have reported contradictory results at 1 year after thrombus aspiration in ST elevation myocardial infarction (STEMI). In a 1-year follow-up of the largest randomised trial of thrombus aspiration, we aimed to clarify the longer-term benefits, to help guide clinical practice.MethodsThe trial of routine aspiration ThrOmbecTomy with PCI versus PCI ALone in Patients with STEMI (TOTAL) was a prospective, randomised, investigator-initiated trial of routine manual thrombectomy versus percutaneous coronary intervention (PCI) alone in 10 732 patients with STEMI. Eligible adult patients (aged ≥18 years) from 87 hospitals in 20 countries were enrolled and randomly assigned (1:1) within 12 h of symptom onset to receive routine manual thrombectomy with PCI or PCI alone. Permuted block randomisation (with variable block size) was done by a 24 h computerised central system, and was stratified by centre. Participants and investigators were not masked to treatment assignment. The trial did not show a difference at 180 days in the primary outcome of cardiovascular death, myocardial infarction, cardiogenic shock, or heart failure. However, the results showed improvements in the surrogate outcomes of ST segment resolution and distal embolisation, but whether or not this finding would translate into a longer term benefit remained unclear...

Early versus delayed invasive intervention in acute coronary syndromes

Earlier trials have shown that a routine invasive strategy improves outcomes in patients with acute coronary syndromes without ST-segment elevation. However, the optimal timing of such intervention remains uncertain.Methods We randomly assigned 3031 patients with acute coronary syndromes to undergo either routine early intervention (coronary angiography ¡Ü24 hours after randomization)or delayed intervention (coronary angiography ¡Ý36 hours after randomization). The primary outcome was a composite of death, myocardial infarction, or stroke at 6 months. A prespecified secondary outcome was death, myocardial infarction, orrefractory ischemia at 6 months.Results Coronary angiography was performed in 97.6% of patients in the early-intervention group (median time, 14 hours) and in 95.7% of patients in the delayed-intervention group (median time, 50 hours). At 6 months, the primary outcome occurred in 9.6%of patients in the early-intervention group, as compared with 11.3% in the delayedintervention group (hazard ratio in the early-intervention group, 0.85; 95% confidence interval [CI], 0.68 to 1.06; P = 0.15). There was a relative reduction of 28% in the secondary outcome of death, myocardial infarction, or refractory ischemia in the early-intervention group (9.5%), as compared with the delayed-intervention group(12.9%) (hazard ratio, 0.72; 95% CI, 0.58 to 0.89; P = 0.003). Prespecified analyses showed that early intervention improved the primary outcome in the third of patients who were at highest risk (hazard ratio, 0.65; 95% CI, 0.48 to 0.89) but not in the two thirds at low-to-intermediate risk (hazard ratio, 1.12; 95% CI, 0.81 to 1.56; P = 0.01 for heterogeneity)...