875 research outputs found
Isotope shift in the dielectronic recombination of three-electron ^{A}Nd^{57+}
Isotope shifts in dielectronic recombination spectra were studied for Li-like
^{A}Nd^{57+} ions with A=142 and A=150. From the displacement of resonance
positions energy shifts \delta E^{142,150}(2s-2p_1/2)= 40.2(3)(6) meV
(stat)(sys)) and \delta E^{142,150}(2s-2p_3/2) = 42.3(12)(20) meV of 2s-2p_j
transitions were deduced. An evaluation of these values within a full QED
treatment yields a change in the mean-square charge radius of ^{142,150}\delta
= -1.36(1)(3) fm^2. The approach is conceptually new and combines the
advantage of a simple atomic structure with high sensitivity to nuclear size.Comment: 10 pages, 3 figures, accepted for publication in Physical Review
Letter
Analytic model for a frictional shallow-water undular bore
We use the integrable Kaup-Boussinesq shallow water system, modified by a
small viscous term, to model the formation of an undular bore with a steady
profile. The description is made in terms of the corresponding integrable
Whitham system, also appropriately modified by friction. This is derived in
Riemann variables using a modified finite-gap integration technique for the
AKNS scheme. The Whitham system is then reduced to a simple first-order
differential equation which is integrated numerically to obtain an asymptotic
profile of the undular bore, with the local oscillatory structure described by
the periodic solution of the unperturbed Kaup-Boussinesq system. This solution
of the Whitham equations is shown to be consistent with certain jump conditions
following directly from conservation laws for the original system. A comparison
is made with the recently studied dissipationless case for the same system,
where the undular bore is unsteady.Comment: 24 page
Genomeâwide studies of von Willebrand factor propeptide identify loci contributing to variation in propeptide levels and von Willebrand factor clearance
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134219/1/jth13401-sup-0001-FigS1-S7.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134219/2/jth13401.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134219/3/jth13401_am.pd
A prioritization protocol for coastal wetland restoration on Molokaʻi, Hawaiʻi
Hawaiian coastal wetlands provide important habitat for federally endangered waterbirds and socio-cultural resources for Native Hawaiians. Currently, Hawaiian coastal wetlands are degraded by development, sedimentation, and invasive species and, thus, require restoration. Little is known about their original structure and function due to the large-scale alteration of the lowland landscape since European contact. Here, we used 1) rapid field assessments of hydrology, vegetation, soils, and birds, 2) a comprehensive analysis of endangered bird habitat value, 3) site spatial characteristics, 4) sea-level rise projections for 2050 and 2100 and wetland migration potential, and 5) preferences of the Native Hawaiian community in a GIS site suitability analysis to prioritize restoration of coastal wetlands on the island of MolokaÊ»i. The site suitability analysis is the first, to our knowledge, to incorporate community preferences, habitat criteria for endangered waterbirds, and sea-level rise into prioritizing wetland sites for restoration. The rapid assessments showed that groundwater is a ubiquitous water source for coastal wetlands. A groundwater-fed, freshwater herbaceous peatland or âcoastal fenâ not previously described in HawaiÊ»i was found adjacent to the coastline at a site being used to grow taro, a staple crop for Native Hawaiians. In traditional ecological knowledge, such a groundwater-fed, agro-ecological system is referred to as a loÊ»ipĆ«nÄwai (spring pond). Overall, 39 plant species were found at the 12 sites; 26 of these were wetland species and 11 were native. Soil texture in the wetlands ranged from loamy sands to silt and silty clays and the mean % organic carbon content was 10.93% ± 12.24 (sd). In total, 79 federally endangered waterbirds, 13 Hawaiian coots (âalae keÊ»okeÊ»o; Fulica alai) and 66 Hawaiian stilts (aeÊ»o; Himantopus mexicanus knudseni), were counted during the rapid field assessments. The site suitability analysis consistently ranked three sites the highest, KaupapaloÊ»i o KaÊ»amola, KakahaiÊ»a National Wildlife Refuge, and Ê»ĆhiÊ»apilo Pond, under three different weighting approaches. Site prioritization represents both an actionable plan for coastal wetland restoration and an alternative protocol for restoration decision-making in places such as HawaiÊ»i where no pristine âreferenceâ sites exist for comparison
Child and parent predictors of picky eating from preschool to school age
Background: Picky eating is prevalent in childhood. Because pickiness concerns parents and is associated with nutrient deficiency and psychological problems, the antecedents of pickiness need to be identified. We propose an etiological model of picky eating involving child temperament, sensory sensitivity and parent-child interaction. Methods: Two cohorts of 4-year olds (born 2003 or 2004) in Trondheim, Norway were invited to participate (97.2% attendance; 82.0% consent rate, n = 2475) and a screen-stratified subsample of 1250 children was recruited. We interviewed 997 parents about their childâs pickiness and sensory sensitivity using the Preschool Age Psychiatric Assessment (PAPA). Two years later, 795 of the parents completed the interview. The Childrenâs Behavior Questionnaire (CBQ) was used to assess childrenâs temperament. Parent- child interactions were videotaped and parental sensitivity (i.e., parental awareness and appropriate responsiveness to childrenâs verbal and nonverbal cues) and structuring were rated using the Emotional Availability Scales (EAS). Results: At both measurement times, 26% of the children were categorized as picky eaters. Pickiness was moderately stable from preschool to school age (OR = 5.92, CI = 3.95, 8.86), and about half of those who displayed pickiness at age 4 were also picky eaters two years later. While accounting for pickiness at age 4, sensory sensitivity at age 4 predicted pickiness at age 6 (OR = 1.25, CI = 1.08, 2.23), whereas temperamental surgency (OR = 0.88, CI = 0.64, 1.22) and negative affectivity (OR = 1.17, CI = 0.75, 1.84) did not. Parental structuring was found to reduce the risk of childrenâs picky eating two years later (OR = 0.90, CI = 0.82, 0.99), whereas parental sensitivity increased the odds for pickiness (OR = 1.10, CI = 1.00, 1.21). Conclusions: Although pickiness is stable from preschool to school age, children who are more sensory sensitive are at higher risk for pickiness two years later, as are children whose parents display relatively higher levels of sensitivity and lower levels of structuring. Our findings suggest that interventions targeting childrenâs sensory sensitivity, as well as parental sensitivity and structuring, might reduce the risk of childhood pickiness. Health care providers should support parents of picky eaters in repeatedly offering unfamiliar and rejected foods to their children without pressure and acknowledging child autonomy
On the Kobayashi-Royden metric for ellipsoids
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46237/1/208_2005_Article_BF01446557.pd
Periapsis and gravitomagnetic precessions of stellar orbits in Kerr and Kerr-de Sitter black hole spacetimes
The exact solution for the motion of a test particle in a non-spherical polar
orbit around a Kerr black hole is derived. Exact novel expressions for frame
dragging (Lense-Thirring effect), periapsis advance and the orbital period are
produced. The resulting formulae, are expressed in terms of Appell's first
hypergeometric function , Jacobi's amplitude function, and Appell's
and Gau\ss hypergeometric function respectively. The exact expression for
frame dragging is applied for the calculation of the Lense-Thirring effect for
the orbits of S-stars in the central arcsecond of our Galaxy assuming that the
galactic centre is a Kerr black hole, for various values of the Kerr parameter
including those supported by recent observations. In addition, we apply our
solutions for the calculation of frame dragging and periapsis advance for
stellar non-spherical polar orbits in regions of strong gravitational field
close to the event horizon of the galactic black hole, e.g. for orbits in the
central milliarcsecond of our galaxy. Such orbits are the target of the GRAVITY
experiment. We provide examples with orbital periods in the range of 100min -
54 days. Detection of such stellar orbits will allow the possibility of
measuring the relativistic effect of periapsis advance with high precision at
the strong field realm of general relativity. Further, an exact expression for
the orbital period of a test particle in a non-circular equatorial motion
around a Kerr black hole is produced. We also derive exact expressions for the
periapsis advance and the orbital period for a test particle in a non-circular
equatorial motion in the Kerr field in the presence of the cosmological
constant in terms of Lauricella's fourth hypergeometric function .Comment: LaTeX file, 46 pages, typos fixed, substantial changes, version
published in Classical and Quantum Gravity, Vol 24 (2007) 1775-180
All-sky search for time-integrated neutrino emission from astrophysical sources with 7 years of IceCube data
Since the recent detection of an astrophysical flux of high energy neutrinos,
the question of its origin has not yet fully been answered. Much of what is
known about this flux comes from a small event sample of high neutrino purity,
good energy resolution, but large angular uncertainties. In searches for
point-like sources, on the other hand, the best performance is given by using
large statistics and good angular reconstructions. Track-like muon events
produced in neutrino interactions satisfy these requirements. We present here
the results of searches for point-like sources with neutrinos using data
acquired by the IceCube detector over seven years from 2008--2015. The
discovery potential of the analysis in the northern sky is now significantly
below , on average
lower than the sensitivity of the previously published analysis of four
years exposure. No significant clustering of neutrinos above background
expectation was observed, and implications for prominent neutrino source
candidates are discussed.Comment: 19 pages, 17 figures, 3 tables; ; submitted to The Astrophysical
Journa
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