4,466 research outputs found
Three-nucleon interactions: dynamics
A discussion is presented of the dynamics underlying three-body nuclear
forces, with emphasis on changes which occurred over several decades.Comment: Talk given at the FM50 symposium, Tokyo, October 200
Three-nucleon interactions: A frontier in nuclear structure
Three-nucleon interactions are a frontier in understanding and predicting the
structure of strongly-interacting matter in laboratory nuclei and in the
cosmos. We present results and discuss the status of first calculations with
microscopic three-nucleon interactions beyond light nuclei. This coherent
effort is possible due to advances based on effective field theory and
renormalization group methods in nuclear physics.Comment: 7 pages, 11 figures, talk at International Symposium on New Facet of
Three-Nucleon Force (FM50), Tokyo, October, 200
Editorial: Physical Review C in its Fortieth Year
This year, 2010, is the 40th anniversary of Physical Review C as a separate
section of the Physical Review. We write here with a double purpose: first, to
describe how PRC has evolved and to explore how this evolution has reflected
changes in the research style and interests of scientists working in nuclear
physics; and second, to solicit suggestions for improvements that will help
guide PRC's future evolution.Comment: Corrected typ
Engineering cell surfaces by covalent grafting of synthetic polymers to metabolically-labeled glycans
Re-engineering mammalian cell surfaces enables modulation of their phenotype, function, and interactions with external markers and may find application in cell-based therapies. Here we use metabolic glycan labeling to install azido groups onto the cell surface, which can act as anchor points to enable rapid, simple, and robust “click” functionalization by the addition of a polymer bearing orthogonally reactive functionality. Using this strategy, new cell surface functionality was introduced by using telechelic polymers with fluorescence or biotin termini, demonstrating that recruitment of biomacromolecules is possible. This approach may enable the attachment of payloads and modulation of cell function and fate, as well as providing a tool to interface synthetic polymers with biological systems
The Blue Tip of the Stellar Locus: Measuring Reddening with the SDSS
We present measurements of reddening due to dust using the colors of stars in
the Sloan Digital Sky Survey (SDSS). We measure the color of main sequence
turn-off stars by finding the "blue tip" of the stellar locus: the prominent
blue edge in the distribution of stellar colors. The method is sensitive to
color changes of order 18, 12, 7, and 8 mmag of reddening in the colors u-g,
g-r, r-i, and i-z, respectively, in regions measuring 90' by 14'. We present
maps of the blue tip colors in each of these bands over the entire SDSS
footprint, including the new dusty southern Galactic cap data provided by the
SDSS-III. The results disfavor the best fit O'Donnell (1994) and Cardelli et
al. (1989) reddening laws, but are well described by a Fitzpatrick (1999)
reddening law with R_V = 3.1. The SFD dust map is found to trace the dust well,
but overestimates reddening by factors of 1.4, 1.0, 1.2, and 1.4 in u-g, g-r,
r-i, and i-z, largely due to the adopted reddening law. In select dusty regions
of the sky, we find evidence for problems in the SFD temperature correction. A
dust map normalization difference of 15% between the Galactic north and south
sky may be due to these dust temperature errors.Comment: 18 pages, 22 figure
Phylogenetically independent behavior mediating geographic distributions suggests habitat is a strong driver of phenotype in crangonyctid amphipods
It is unclear if geographic distributions of animals are behaviorally mediated or simply maintained by ecologically-driven deleterious effects on fitness. Furthermore, it is not well known how behaviors that may affect geographic distributions and responses to environmental stressors evolve. To explore this, we examined behavioral and physiological reactions to light in six species of amphipods in the family Crangonyctidae collected from a variety of subterranean and epigean habitats. Stark differences between epigean and subterranean habitats occupied by different crangonyctid species allowed this clade to serve as an appropriate model system for studying the link between habitat and phenotype. We sampled habitats in or adjacent to the Edwards Aquifer in central Texas and collected two epigean and four stygobiontic species. We examined respiratory and behavioral responses to light in all study species. We found that similarities in behavioral and physiological responses to light between species were only weakly correlated with genetic relatedness but were correlated with habitat type. However, the breadth of variation in phenotype was found to be correlated with phylogenetic relationships, suggesting that population level trait evolution likely involves interactions between standing population level variation and strength of selection. Our findings suggest that natural selection via environmental conditions may outweigh history of common ancestry when predicting phenotypic similarities among species, and that behavioral and physiological phenotypes may mediate the evolution of biogeographic distributions
The long-term Illinois rivers fish population monitoring program 2014
This report presents a summary of those data collected during segment 26(2014-15) of the Long-term Illinois Rivers Fish Population Monitoring Program(LTEF), an annual survey executed by members of the Illinois Natural History Survey with funds administered by the U.S. Fish and Wildlife Service and the Illinois Department of Natural Resources. Sampling for the LTEF program was conducted on: six reaches of the Illinois River Waterway, six segments or pools of the Mississippi River, and navigable portions of the Iroquois and Kankakee Rives. In all segments of the LTEF program, all fish species collected were accurately identified, tallied, measured, and weighed. The catch rates of sportfish species were calculated as the number of individuals collected per hour (CPUEN± standard error). Structural indices [Proportional Size Distribution (PSD) and Relative Weight (Wr)] were also calculated for species of interest to regional managers. Catch rates and species richness varied greatly among all sampling locations and sampling periods. Emerald Shiners and Gizzard Shad comprised the majority of the individuals caught, and Silver Carp and Common Carp accounted for the greatest proportion of the biomass collected in most sampling areas of the survey. The analysis of CPUEN and PSD trends in sportfish populations sampled by the program may indicate inter-annual recruitment patterns in sportfish populations around the state. Both Shovelnose Sturgeon and Blue Catfish were the two species most commonly encountered in the gill net surveys.IDNR Division of Fisheries Project F-101-R, Segment 26unpublishednot peer reviewe
Constraints on the Galactic bar from the Hercules stream as traced with RAVE across the Galaxy
Non-axisymmetries in the Galactic potential (spiral arms and bar) induce kinematic groups such as the Hercules stream. Assuming that Hercules is caused by the effects of the outer Lindblad resonance of the Galactic bar, we model analytically its properties as a function of position in the Galaxy and its dependence on the bar's pattern speed and orientation. Using data from the RAVE survey we find that the azimuthal velocity of the Hercules structure decreases as a function of Galactocentric radius, in a manner consistent with our analytical model. This allows us to obtain new estimates of the parameters of the Milky Way's bar. The combined likelihood function of the bar's pattern speed and angle has its maximum for a pattern speed of Omega(b) = (1.89 +/- 0.08) x Omega(0), where Omega(0) is the local circular frequency. Assuming a solar radius of 8.05 kpc and a local circular velocity of 238 km s(-1), this corresponds to Omega(b) = 56 +/- 2km s(-1) kpc(-1). On the other hand, the bar's orientation phi(b) cannot be constrained with the available data. In fact, the likelihood function shows that a tight correlation exists between the pattern speed and the orientation, implying that a better description of our best fit results is given by the linear relation Omega(b)/Omega(0) = 1.91+0.0044 (phi(b)(deg) - 48), with standard deviation of 0.02. For example, for an angle of phi(b) = 30 deg the pattern speed is 54.0 +/- 0.5 km s(-1) kpc(-1). These results are not very sensitive to the other Galactic parameters such as the circular velocity curve or the peculiar motion of the Sun, and are robust to biases in distance
Over 50 years of fish community monitoring in Illinois’ large rivers: The evolution of methods used by the Illinois Natural History Survey’s Long-term Survey and Assessment of Large-River Fishes in Illinois
Federal Aid in Sport Fish Restoration Act (F-101-R), administered by the U.S. Fish and Wildlife Service and Illinois Department of Natural Resourcesis peer reviewedOpe
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The Blue Tip of the Stellar Locus: Measuring Reddening with the Sloan Digital Sky Survey
We present measurements of reddening due to dust using the colors of stars in the Sloan Digital Sky Survey (SDSS). We measure the color of main-sequence turnoff stars by finding the "blue tip" of the stellar locus: the prominent blue edge in the distribution of stellar colors. The method is sensitive to color changes of order 18, 12, 7, and 8 mmag of reddening in the colors u – g, g – r, r – i, and i – z, respectively, in regions measuring 90' by 14'. We present maps of the blue tip colors in each of these bands over the entire SDSS footprint, including the new dusty southern Galactic cap data provided by the SDSS-III. The results disfavor the best-fit O'Donnell and Cardelli et al. reddening laws, but are described well by a Fitzpatrick reddening law with RV = 3.1. The Schlegel et al. (SFD) dust map is found to trace the dust well, but overestimates reddening by factors of 1.4, 1.0, 1.2, and 1.4 in u – g, g – r, r – i, and i – z largely due to the adopted reddening law. In select dusty regions of the sky, we find evidence for problems in the SFD temperature correction. A dust map normalization difference of 15% between the Galactic north and south sky may be due to these dust temperature errors.Astronom
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