125,163 research outputs found
Gravitational Acceleration of Spinning Bodies From Lunar Laser Ranging Measurements
The Sun's relativistic gravitational gradient accelerations of Earth and
Moon, dependent on the motions of the latter bodies, act upon the system's
internal angular momentum. This spin-orbit force (which plays a part in
determining the gravity wave signal templates for astrophysical sources)
slightly accelerates the Earth-Moon system as a whole, but it more robustly
perturbs that system's internal dynamics with a 5 cm, synodically oscillating
range contribution which is presently measured to 4 mm precision by more than
three decades of lunar laser ranging.Comment: 10 pages, PCTex32.v3.
In-medium electron-nucleon scattering
In-medium nucleon electromagnetic form factors are calculated in the quark
meson coupling model. The form factors are typically found to be suppressed as
the density increases. For example, at normal nuclear density and , the nucleon electric form factors are reduced by approximately 8%
while the magnetic form factors are reduced by only 1 - 2%. These variations
are consistent with current experimental limits but should be tested by more
precise experiments in the near future.Comment: 14 pages, latex, 3 figure
Recall of physical activity advice was associated with higher levels of physical activity in colorectal cancer patients.
The present study tested the hypothesis that recall of receiving physical activity (PA) advice would be associated with higher levels of PA in patients with a diagnosis of colorectal cancer (CRC)
Ion Exchange-Precipitation for Nutrient Recovery from Dilute Wastewater
Regulated phosphorus (P) and nitrogen (N) discharges and the cost of fertilizer provide economic drivers for nutrient removal and recovery from wastewater. This study used ion exchange (IX) in dilute (domestic) wastewater to concentrate nutrients with subsequent recovery by struvite precipitation. This is the first tertiary wastewater treatment study directly comparing P removal using a range of Fe, Cu, and Al-based media followed by clinoptilolite IX columns for N removal and precipitation using the combined regenerants. Phosphate removal prior to breakthrough was 0.5–2.0 g P Lmedia−1, providing effluent concentrations −1 PO4-P and −1 NH4-N for ≥80 bed volumes. Dow-FeCu resin provided effective P removal, efficient neutral pH regeneration and 560 mg P L−1 in the regeneration eluate (≥100× concentration factor). Exchange capacity of clinoptilolite in column mode was 3.9–6.1 g N Lmedia−1 prior to breakthrough. Precipitation using the combined cation and anion regenerants resulted in a maximum of 74% P removal using Dow-FeCu. Precipitates contained impurities, including Al3+, Ca2+, and Fe. Overall, the IX-precipitation recovery process removed ≥98% P and 95% N and precipitates contained 13% P and 1.6% N. This sequential process can satisfy increasingly stringent wastewater standards and offers an effective alternative to traditional treatment technologies that simply remove nutrients. Approximately 84% of total P and 97% of total Kjeldahl N entering a treatment plant can be captured (accounting for primary clarifier removal), whereas most existing technologies target side streams that typically contain only 20–30% of influent P and 15–20% of influent N
The open cluster initial-final mass relationship and the high-mass tail of the white dwarf distribution
Recent studies of white dwarfs in open clusters have provided new constraints
on the initial - final mass relationship (IFMR) for main sequence stars with
masses in the range 2.5 - 6.5 Mo. We re-evaluate the ensemble of data that
determines the IFMR and argue that the IFMR can be characterised by a mean
initial-final mass relationship about which there is an intrinsic scatter. We
investigate the consequences of the IFMR for the observed mass distribution of
field white dwarfs using population synthesis calculations. We show that while
a linear IFMR predicts a mass distribution that is in reasonable agreement with
the recent results from the PG survey, the data are better fitted by an IFMR
with some curvature. Our calculations indicate that a significant (~28%)
percentage of white dwarfs originating from single star evolution have masses
in excess of ~0.8 Mo, obviating the necessity for postulating the existence of
a dominant population of high-mass white dwarfs that arise from binary star
mergers.Comment: 5 pages, 2 color Postscript figures. Accepted for publication in
MNRA
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