Resolution of a paradox: Hummingbird flight at high elevation does not come without a cost

Flight at high elevation is energetically demanding because of parallel reductions in air density and oxygen availability. The hovering flight of hummingbirds is one of the most energetically expensive forms of animal locomotion, but hummingbirds are nonetheless abundant at high elevations throughout the Americas. Two mechanisms enhance aerodynamic performance in high-elevation hummingbirds: increase in wing size and wing stroke amplitude during hovering. How do these changes in morphology, kinematics, and physical properties of air combine to influence the aerodynamic power requirements of flight across elevations? Here, we present data on the flight performance of 43 Andean hummingbird species as well as a 76-taxon multilocus molecular phylogeny that served as the historical framework for comparative analyses. Along a 4,000-m elevational transect, hummingbird body mass increased systematically, placing further aerodynamic demands on high-elevation taxa. However, we found that the minimum power requirements for hovering flight remain constant with respect to elevation because hummingbirds compensate sufficiently through increases in wing size and stroke amplitude. Thus, high-elevation hummingbirds are not limited in their capacity for hovering flight despite the challenges imposed by hypobaric environments. Other flight modes including vertical ascent and fast forward flight are more mechanically and energetically demanding, and we accordingly also tested for the maximum power available to hummingbirds by using a load-lifting assay. In contrast to hovering, excess power availability decreased substantially across elevations, thereby reducing the biomechanical potential for more complex flight such as competitive and escape maneuvers

The Quantitve Measurement of Amalgamation

Mercury has been known since ancient times. In fact, one mine, the Almaden in Spain, has been worked continuously since Roman times. It has been used during all this time for the recovery of free gold from gold concentrates, and from black sand and galena in concentrates from placer work

Broadening Participation in Research Focused, Upper-Division Learning Communities

We address several challenges faced by those who wish to increase the number of faculty participating in upper-division learning communities that feature a student research experience. Using illustrations from our own learning community, we describe three strategies for success that focus on providing low cost incentives and other means to promote and sustain faculty cooperation

An Economic Interpretation of Rhode Island’s 1788 Referendum on the Constitution

In their 1788 popular referendum, Rhode Island voters overwhelmingly rejected ratification of the Federal Constitution: 92 percent against and 8 percent for adoption. The town-by-town voter lists, correlated with tax and estate records, show that yea voters were significantly wealthier than “nay” voters. Available data also indicates that yea wealth was concentrated in personal estate rather than real estate. Both these findings support Charles Beard\u27s original economic interpretation of the Constitution. Our detailed data provides new evidence about town-level voters, supplementing the usual data Beard’s supporters and critics have used from state ratifying conventions and the Philadelphia constitutional convention. We trace the outlines of the scholarly debate, provide political and economic context for the Rhode Island referendum, report on our initial findings, and suggest further avenues of research and analysis

Implementation and performance of SIBYLS: a dual endstation small-angle X-ray scattering and macromolecular crystallography beamline at the Advanced Light Source.

The SIBYLS beamline (12.3.1) of the Advanced Light Source at Lawrence Berkeley National Laboratory, supported by the US Department of Energy and the National Institutes of Health, is optimized for both small-angle X-ray scattering (SAXS) and macromolecular crystallography (MX), making it unique among the world's mostly SAXS or MX dedicated beamlines. Since SIBYLS was commissioned, assessments of the limitations and advantages of a combined SAXS and MX beamline have suggested new strategies for integration and optimal data collection methods and have led to additional hardware and software enhancements. Features described include a dual mode monochromator [containing both Si(111) crystals and Mo/B(4)C multilayer elements], rapid beamline optics conversion between SAXS and MX modes, active beam stabilization, sample-loading robotics, and mail-in and remote data collection. These features allow users to gain valuable insights from both dynamic solution scattering and high-resolution atomic diffraction experiments performed at a single synchrotron beamline. Key practical issues considered for data collection and analysis include radiation damage, structural ensembles, alternative conformers and flexibility. SIBYLS develops and applies efficient combined MX and SAXS methods that deliver high-impact results by providing robust cost-effective routes to connect structures to biology and by performing experiments that aid beamline designs for next generation light sources

How behavioral economics can help to avoid ‘The last mile problem’ in whole genome sequencing

Editorial summary Failure to consider lessons from behavioral economics in the case of whole genome sequencing may cause us to run into the ‘last mile problem’ - the failure to integrate newly developed technology, on which billions of dollars have been invested, into society in a way that improves human behavior and decision-making