25 research outputs found
Investigating the Near-Infrared Properties of Planetary Nebula II. Medium Resolution Spectra
We present medium-resolution (R~700) near-infrared (lambda = 1 - 2.5 micron)
spectra of a sample of planetary nebulae (PNe). A narrow slit was used which
sampled discrete locations within the nebulae; observations were obtained at
one or more positions in the 41 objects included in the survey. The PN spectra
fall into one of four general categories: H I emission line-dominated PNe, H I
and H_2 emission line PNe, H_2-dominated PNe, and continuum-dominated PNe.
These categories correlate with morphological type, with the elliptical PNe
falling into the first group, and the bipolar PNe primarily in the H_2 and
continuum emission groups. Other spectral features were observed in all
categories, such as continuum emission from the central star, C_2, CN, and CO
emission, and warm dust continuum emission.
Molecular hydrogen was detected for the first time in four PNe. An excitation
analysis was performed using the H_2 line ratios for all of the PN spectra in
the survey where a sufficient number of lines were observed. One unexpected
result from this analysis is that the H_2 is excited by absorption of
ultraviolet photons in most of the PNe surveyed, although for several PNe in
our survey collisional excitation in moderate velocity shocks plays an
important role. The correlation between bipolar morphology and H_2 emission has
been strengthened with the new detections of H_2 in this survey.Comment: 13 pages, 8 tables, 33 figure
Genomic screening of 16 UK native bat species through conservationist networks uncovers coronaviruses with zoonotic potential
There has been limited characterisation of bat-borne coronaviruses in Europe. Here, we screened for coronaviruses in 48 faecal samples from 16 of the 17 bat species breeding in the UK, collected through a bat rehabilitation and conservationist network. We recovered nine complete genomes, including two novel coronavirus species, across six bat species: four alphacoronaviruses, a MERS-related betacoronavirus, and four closely related sarbecoviruses. We demonstrate that at least one of these sarbecoviruses can bind and use the human ACE2 receptor for infecting human cells, albeit suboptimally. Additionally, the spike proteins of these sarbecoviruses possess an R-A-K-Q motif, which lies only one nucleotide mutation away from a furin cleavage site (FCS) that enhances infectivity in other coronaviruses, including SARS-CoV-2. However, mutating this motif to an FCS does not enable spike cleavage. Overall, while UK sarbecoviruses would require further molecular adaptations to infect humans, their zoonotic risk warrants closer surveillance
Scaling of maneuvering performance in baleen whales: larger whales outperform expectations
Despite their enormous size, whales make their living as voracious predators. To catch their much smaller, more maneuverable prey, they have developed several unique locomotor strategies that require high energetic input, high mechanical power output and a surprising degree of agility. To better understand how body size affects maneuverability at the largest scale, we used bio-logging data, aerial photogrammetry and a high-throughput approach to quantify the maneuvering performance of seven species of free-swimming baleen whale. We found that as body size increases, absolute maneuvering performance decreases: larger whales use lower accelerations and perform slower pitch-changes, rolls and turns than smaller species. We also found that baleen whales exhibit positive allometry of maneuvering performance: relative to their body size, larger whales use higher accelerations, and perform faster pitch-changes, rolls and certain types of turns than smaller species. However, not all maneuvers were impacted by body size in the same way, and we found that larger whales behaviorally adjust for their decreased agility by using turns that they can perform more effectively. The positive allometry of maneuvering performance suggests that large whales have compensated for their increased body size by evolving more effective control surfaces and by preferentially selecting maneuvers that play to their strengths.We thank the crews of many research vessels including the R/V John Martin, R/V Fluke, ARSV Laurence M. Gould, R/V Sanna, M/V Antonie, M/V Northern Song, the Cascadia Research Collective and the Shallow Marine Surveys Group; in particular, we thank John Douglas, Andrew Bell, Shaun Tomlinson, Steve Cartwright, Tony D'Aoust, Dennis Rogers, Kelly Newton, Heather Riley, Gina Rousa and Mark Rousa. We also thank Brandon L. Southall, Alison K. Stimpert and Stacy L. DeRuiter for their role in collecting data as part of the SOCAL-BRS project. We thank Matt S. Savoca, Julian Dale and Danuta M. Wisniewska for assistance with data collection. Finally, we thank John H. Kennedy, Michael A. Thompson and the NSF Office of Polar Programs.Ye
Psychosocial experiences in the context of life-threatening illness: The cardiac rehabilitation patient
"Chocolate City" Politics: Race and Empowerment in the First Post-Katrina New Orleans Mayoral Election
Scaling of maneuvering performance in baleen whales: larger whales outperform expectations
Despite their enormous size, whales make their living as voracious predators. To catch their much smaller, more maneuverable prey, they have developed several unique locomotor strategies that require high energetic input, high mechanical power output and a surprising degree of agility. To better understand how body size affects maneuverability at the largest scale, we used bio-logging data, aerial photogrammetry and a high-throughput approach to quantify the maneuvering performance of seven species of free-swimming baleen whale. We found that as body size increases, absolute maneuvering performance decreases: larger whales use lower accelerations and perform slower pitch changes, rolls and turns than smaller species. We also found that baleen whales exhibit positive allometry of maneuvering performance: relative to their body size, larger whales use higher accelerations, and perform faster pitch-changes, rolls and certain types of turns than smaller species. However, not all maneuvers were impacted by body size in the same way, and we found that larger whales behaviorally adjust for their decreased agility by using turns that they can perform more effectively. The positive allometry of maneuvering performance suggests that large whales have compensated for their increased body size by evolving more effective control surfaces and by preferentially selecting maneuvers that play to their strengths
SYNTHESIS OF FORMAMIDE AND RELATED ORGANIC SPECIES IN THE INTERSTELLAR MEDIUM VIA CHEMICAL DYNAMICS SIMULATIONS
Risk Compensation or Risk Reduction? Seatbelts, State Laws, and Traffic Fatalities
The risk compensation hypothesis suggests that drivers enjoying greater safety will drive more recklessly and thereby impose greater risks on nonoccupants. We provide a test of the risk compensation hypothesis in the context of state seatbelt laws and belt use rates. Copyright (c) 2007 by the Southwestern Social Science Association.