7,757 research outputs found
Who is my neighbour? Understanding indifference as a vice
Indifference is often described as a vice. Yet who is indifferent; to what; and in what way is poorly understood, and frequently subject to controversy and confusion. This paper proposes a framework for the interpretation and analysis of ethically problematic forms of indifference in terms of how different states of indifference can be either more or less dynamic, or more or less sensitive to the nature and state of their object
Coastal Science for Resilience and Management at the Cape Hatteras National Seashore, NC, USA
National seashores are cherished public lands with rich environmental, cultural, and historic resources. The Cape Hatteras National Seashore is one such coastal asset that is both bountiful yet vulnerable, with historic lighthouses, critical habitats, and recreational amenities alike facing threats of sea-level rise and continual storm and climate change impacts. Over 3 million visitors to the Seashore in 2021 set an annual visitation record. Historic resources such as the Bodie Island Lighthouse and Ocracoke Lighthouse are among the most visited sites, yet these assets are also among those most vulnerable to flooding, compromised structural integrity, and reduced accessibility. Future challenges to the protection and management of such resources are already being felt in the form of storms, extreme rainfall, and recurrent compound flooding. Such threats are also coincident with increasing visitation and recreational demand. This paper examines the science-based data that are being collected and management efforts underway to inform future planning, intervention, or adaptation to sea-level rise and barrier island evolution. The paper identifies the opportunities for mitigation and adaptation as well as potential environmental tipping points and limits to resilience by assessing the frequency and magnitude of flooding events and shoreline change
Low State, Phase-Resolved IR Spectroscopy of VV Puppis
We present phase-resolved low resolution and higher resolution -band
spectroscopy of the polar VV Pup. All observations were obtained when VV Pup
was in a low accretion state having a K magnitude near 15. The low resolution
observations reveal cyclotron emission in the band during some phases,
consistent with an origin near the active 30.5 MG pole on the white dwarf. The
secondary in VV Pup appears to be a normal M7V star and we find that the
and band fluxes are entirely due to this star at all orbital phases during
the low accretion state. We use our higher resolution Keck spectroscopy to
produce the first -band radial velocity curve for VV Pup. Our orbital
solution yields =414 km sec and leads to mass estimates of
M=0.730.05 M and M=0.100.02 M. We find
that the mass accretion rates during the normal low states of the polars VV
Pup, EF Eri, and EQ Cet are near 10 M yr. The fact
that \.M is not zero in low state polars indicates active secondary stars in
these binary systems, including the sub-stellar donor star present in EF Eri.Comment: Accepted in Astronomical Journal 5 figure
Postexposure Treatment of Marburg Virus Infection
Rhesus monkeys are protected from disease when a recombinant vesicular stomatitis virus–based vaccine is administered 20–30 min after infection with Marburg virus. We protected 5/6 monkeys when this vaccine was given 24 h after challenge; 2/6 animals were protected when the vaccine was administered 48 h postinfection
Optical vortex trap for resonant confinement of metal nanoparticles
The confinement and controlled movement of metal nanoparticles and nanorods is an emergent area within optical micromanipulation. In this letter we experimentally realise a novel trapping geometry near the plasmon resonance using an annular light field possessing a helical phasefront that confines the nanoparticle to the vortex core (dark) region. We interpret our data with a theoretical framework based upon the Maxwell stress tensor formulation to elucidate the total forces upon nanometric particles near the particle plasmon resonance. Rotation of the particle due to orbital angular momentum transfer is observed. This geometry may have several advantages for advanced manipulation of metal nanoparticles
Multiwavelength all-optical clock recovery
©1999 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEEMultiwavelength clock recovery is especially desirable in systems that use wavelength-division-multipleged technology. A multiwavelength clock-recovery device can greatly simplify costs by eliminating the need to have a separate regenerator for each wavelength. This letter discusses multiwavelength all-optical clock recovery using stimulated Brillouin scattering
Beryllium abundances in metal-poor stars
We have determined beryllium abundances for 25 metal-poor stars based on the
high resolution and high signal-to-noise ratio spectra from the VLT/UVES
database. Our results confirm that Be abundances increase with Fe, supporting
the global enrichment of Be in the Galaxy. Oxygen abundances based on [O I]
forbidden line implies a linear relation with a slope close to one for the Be
vs. O trend, which indicates that Be is probably produced in a primary process.
Some strong evidences are found for the intrinsic dispersion of Be abundances
at a given metallicity. The deviation of HD132475 and HD126681 from the general
Be vs. Fe and Be vs. O trend favours the predictions of the superbubble model,
though the possibility that such dispersion originates from the inhomogeneous
enrichment in Fe and O of the protogalactic gas cannot be excluded.Comment: 12 pages with 9 figures, to be published in MNRA
NLTE analysis of Co I/Co II lines in spectra of cool stars with new laboratory hyperfine splitting constants
We investigate the statistical equilibrium of Co in the atmospheres of cool
stars, and the influence of NLTE and HFS (hyperfine splitting) on the formation
of Co lines and abundances. Significant departures from LTE level populations
are found for Co I, also number densities of excited states in Co II differ
from LTE at low metallicity. The NLTE abundance of Co in solar photosphere is
4.95 +/- 0.04 dex, which is in agreement with that in C I meteorites within the
combined uncertainties. The spectral lines of Co I were calculated using the
results of recent measurements of hyperfine interaction constants by UV Fourier
transform spectrometry. For Co II, the first laboratory measurements of
hyperfine structure splitting A and B factors were performed. A differential
abundance analysis of Co is carried out for 18 stars in the metallicity range
-3.12 < [Fe/H] < 0. The abundances are derived by method of spectrum synthesis.
At low [Fe/H], NLTE abundance corrections for Co I lines are as large as +0.6
>... +0.8 dex. Thus, LTE abundances of Co in metal-poor stars are severely
underestimated. The stellar NLTE abundances determined from the single UV line
of Co II are lower by ~0.5-0.6 dex. The discrepancy might be attributed to
possible blends that have not been accounted for in the solar Co II line and
its erroneous oscillator strength. The increasing [Co/Fe] trend in metal-poor
stars, as calculated from the Co I lines under NLTE, can be explained if Co is
overproduced relative to Fe in massive stars. The models of galactic chemical
evolution are wholly inadequate to describe this trend suggesting that the
problem is in SN yields.Comment: submitted to MNRAS, 15 page
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