Contractile properties of the pigeon supracoracoideus during different modes of flight

The supracoracoideus (SUPRA) is the primary upstroke muscle for avian flight and is the antagonist to the downstroke muscle, the pectoralis (PECT). We studied in vivo contractile properties and mechanical power output of both muscles during take-off, level and landing flight. We measured muscle length change and activation using sonomicrometry and electromyography, and muscle force development using strain recordings on the humerus. Our results support a hypothesis that the primary role of the SUPRA is to supinate the humerus. Antagonistic forces exerted by the SUPRA and PECT overlap during portions of the wingbeat cycle, thereby offering a potential mechanism for enhancing control of the wing. Among flight modes, muscle strain was approximately the same in the SUPRA (33–40%) and the PECT (35–42%), whereas peak muscle stress was higher in the SUPRA $(85–126 N m^{–2})$ than in the PECT $(50–58 N m^{–2})$. The SUPRA mainly shortened relative to resting length and the PECT mainly lengthened. We estimated that elastic energy storage in the tendon of the SUPRA contributed between 28 and 60% of the net work of the SUPRA and 6–10% of the total net mechanical work of both muscles. Mechanical power output in the SUPRA was congruent with the estimated inertial power required for upstroke, but power output from the PECT was only 42–46% of the estimated aerodynamic power requirements for flight. There was a significant effect of flight mode upon aspects of the contractile behavior of both muscles including strain, strain rate, peak stress, work and power.Organismic and Evolutionary BiologyOther Research Uni

The Planar Electrode Linear Ion Trap

We present a linear type ion trap consisting of metal lines that are lithographically patterned onto two ceramic substrates. Trapping fields are realized by applying specific voltage potentials to each line. This arrangement allows miniaturization approaches that are immune to surface roughness issues and increased complexities of precision machining of electrode surfaces. We also present how these traps allow a thorough study of higher order multipoles and their effect on mass analyzer performance

Planar Electrode Quadrupole Ion Traps

We present a linear type ion trap consisting of metal lines that are lithographically patterned onto two ceramic substrates. Trapping fields are realized by applying specific voltage potentials to each line. This arrangement allows miniaturization approaches that are immune to surface roughness issues and increased complexities of precision machining of electrode surfaces. We also present how these traps allow a thorough study of higher order multipoles and their effect on mass analyzer performance

Structural Characteristics of Carbon Nanofibers for On-chip Interconnect Applications

In this letter, we compare the structures of plasma-enhanced chemical vapor deposition of Ni-catalyzed and Pd-catalyzed carbon nanofibers (CNFs) synthesized for on-chip interconnect applications with scanning transmission electron microscopy (STEM). The Ni-catalyzed CNF has a conventional fiberlike structure and many graphitic layers that are almost parallel to the substrate at the CNF base. In contrast, the Pd-catalyzed CNF has a multiwall nanotubelike structure on the sidewall spanning the entire CNF. The microstructure observed in the Pd-catalyzed fibers at the CNF-metal interface has the potential to lower contact resistance significantly, as our electrical measurements using current-sensing atomic force microscopy indicate. A structural model is presented based on STEM image analysis

Analysis of the Two-Level NO PLIF Model for Low-Temperature High-Speed Flow Applications

The current work compares experimentally obtained nitric oxide (NO) laser-induced fluorescence (LIF) spectra with the equivalent spectra obtained analytically. The experimental spectra are computed from captured images of fluorescence in a gas cell and from a laser sheet passing through the fuel-air mixing flowfield produced by a high-speed fuel injector. The fuel injector is a slender strut that is currently being studied as a part of the Enhanced Injection and Mixing Project (EIMP) at the NASA Langley Research Center. This injector is placed downstream of a Mach 6 facility nozzle, which simulates the high Mach number airflow at the entrance of a scramjet combustor, and injects helium, which is used as an inert substitute for hydrogen fuel. Experimental planar (P) LIF is obtained by using a UV laser to excite fluorescence from the NO molecules that are present in either a gas cell or the facility air used for the EIMP experiments. The experimental data are obtained for several segments of the NO fluorescence spectrum. The selected segments encompass LIF lines with rotational quantum numbers appropriate for low-to-moderate temperature flows similar to those corresponding to the nominal experimental flow conditions. The experimental LIF spectra are then evaluated from the data and compared with those obtained from the theoretical models. The theoretical spectra are obtained from LIFBASE and LINUS software, and from a simplified version of the two-level fluorescence model. The equivalent analytic PLIF images are also obtained by applying only the simplified model to the results of the Reynolds-averaged simulations (RAS) of the mixing flowfield. Good agreement between the experimental and theoretical results provides increased confidence in both the simplified LIF modeling and CFD simulations for further investigations of high-speed injector performance using this approach

The ecology of C-genotype and E-genotype strains of the bacterium Vibrio vulnificus and their interactions with the American oyster Crassostrea virginica

Vibrio vulnificus is a pathogenic bacterium, routinely found in waters of estuarine environments as part of the normal microflora. This organism can be divided into two genotypes, a C-type associated with clinical isolation, and an E-type associated with environmental isolation. While it was previously known that C- and E-type cells were genetically distinct, a further distinction was found among C-type strains that has the potential to predict pathogenicity using simple PCR. It was also found that C- types cells are more rapidly taken up by oyster hosts than E-type cells in some cases, but that depuration was just as rapid for both types. These studies revealed that addition of laboratory grown bacterial strains can cause endogenous bacteria in oyster to resuscitate from the viable-but-non-culturable state. Inefficiencies in bacterial uptake in oysters led to a study that concludes that E-type strains are more readily integrated into marine aggregates that C-type strains. Most notably, V. vulnificus was observed to decline in North Carolina estuaries in response to a prolonged and severe drought

Maximization of fitness by phenological and phenotypic plasticity in range expanding rabbitfishes (Siganidae)

Global warming is modifying the phenology, life-history traits and biogeography of species around the world. Evidence of these effects have increased over recent decades; however, we still have a poor understanding of the possible outcomes of their interplay across global climatic gradients, hindering our ability to accurately predict the consequences of climate change in populations and ecosystems.publishedVersio