3,555 research outputs found
The importance of poverty early in childhood
Introduction: Using a poverty line set at 60% of New Zealand’s median national income, nearly one in five New Zealand children (19%) was poor in 2011. This poverty rate is considerably less than that of the United States and Canada, similar to that of Australia, the United Kingdom, Germany and France, and much greater that in Scandinavian countries. These rates are far from immutable; New Zealand’s child poverty rate was much higher in 2004 before social policies were enacted which focused, in part, on the country’s child poverty problem
A Checklist of Illinois Centipedes (Chilopoda): Supplement
(excerpt)
Order SCOLOPENDROMORPHA Family CRYFTOPIDAE Subfamily CRYFTOPINAE
Cryptops hyalinus Say 1821. (Fig. 2). B (Cook; Auerbach [1951]), C (Champaign) F (Hardin, Jackson, Johnson, Pope, Saline, Williamson), G (Jackson, Jefferson, Perry, Williamson),
H (Clark), I (Randolph, Union), J (Alexander)
Energy Dependence of Cu L2,3 Satellites using Synchrotron Excited X-ray Emission Spectroscopy
The L2,3 X-ray emission of Cu metal has been measured using monochromatic
synchrotron radiation. The self-absorption effect in the spectra is shown to be
very small in our experimental geometry. From the quantitative analysis of
spectra recorded at different excitation energies, the L3/L2 emission intensity
ratio and the partial Auger-width are extracted. High-energy satellite features
on the L3 emission line are separated by a subtraction procedure. The satellite
intensity is found to be slowly increasing for excitation energies between the
L3, L2 and L1 core-level thresholds due to shake-up and shake-off transitions.
As the excitation energy passes the L2 threshold, a step of rapidly increasing
satellite intensity of the L3 emission is found due to additional Coster-Kronig
processes.Comment: 8 pages, 3 figures, http://link.aps.org/doi/10.1103/PhysRevB.56.1223
Does Prekindergarten Improve School Preparation and Performance?
Prekindergarten programs are expanding rapidly, but to date, evidence on their effects is quite limited. Using rich data from Early Childhood Longitudinal Study, we estimate the effects of prekindergarten on children's school readiness. We find that prekindergarten increases reading and mathematics skills at school entry, but also increases behavioral problems and reduces self-control. Furthermore, the effects of prekindergarten on skills largely dissipate by the spring of first grade, although the behavioral effects do not. Finally, effects differ depending on children's family background and subsequent schooling, with the largest and most lasting academic gains for disadvantaged children and those attending schools with low levels of academic instruction.
The interaction of oxygen atoms with solid surfaces at eV energies Annual status report, 1 Jun. 1968 - 31 May 1969
Interaction of oxygen atoms with solid surfaces at eV energie
X-ray fluorescence spectra of metals excited below threshold
X-ray scattering spectra of Cu and Ni metals have been measured using
monochromatic synchrotron radiation tuned from far above to more than 10 eV
below threshold. Energy conservation in the scattering process is found to be
sufficient to explain the modulation of the spectral shape, neglecting momentum
conservation and channel interference. At excitation energies close to and
above threshold, the emission spectra map the occupied local partial density of
states. For the sub-threshold excitations, the high-energy flank of the
inelastic scattering exhibits a Raman-type linear dispersion, and an asymmetric
low energy tail develops. For excitation far below threshold the emission
spectra are proportional to a convolution of the occupied and unoccuppied local
partial densities of states.Comment: 10 pages, 3 figures,
http://link.aps.org/doi/10.1103/PhysRevB.68.04511
Ecological Significance of a Drifting Object to Pelagic Fishes
Volume: 21Start Page: 486End Page: 49
Coherent Excitation of the 6S1/2 to 5D3/2 Electric Quadrupole Transition in 138Ba+
The electric dipole-forbidden, quadrupole 6S1/2 5D3/2 transition in Ba+
near 2051 nm, with a natural linewidth of 13 mHz, is attractive for potential
observation of parity non-conservation, and also as a clock transition for a
barium ion optical frequency standard. This transition also offers a direct
means of populating the metastable 5D3/2 state to measure the nuclear magnetic
octupole moment in the odd barium isotopes. Light from a diode-pumped, solid
state Tm,Ho:YLF laser operating at 2051 nm is used to coherently drive this
transition between resolved Zeeman levels in a single trapped 138Ba+ ion. The
frequency of the laser is stabilized to a high finesse Fabry Perot cavity at
1025 nm after being frequency doubled. Rabi oscillations on this transition
indicate a laser-ion coherence time of 3 ms, most likely limited by ambient
magnetic field fluctuations.Comment: 5 pages, 5 figure
Electronic structure and chemical bonding in Ti4SiC3 investigated by soft x-ray emission spectroscopy and first principle theory
The electronic structure in the new transition metal carbide Ti4SiC3 has been
investigated by bulk-sensitive soft x-ray emission spectroscopy and compared to
the well-studied Ti3SiC2 and TiC systems. The measured high-resolution Ti L, C
K and Si L x-ray emission spectra are discussed with ab initio calculations
based on density-functional theory including core-to-valence dipole matrix
elements. The detailed investigations of the Ti-C and Ti-Si chemical bonds
provide increased understanding of the physical properties of these
nanolaminates. A strongly modified spectral shape is detected for the buried Si
monolayers due to Si 3p hybridization with the Ti 3d orbitals. As a result of
relaxation of the crystal structure and the charge-transfer from Ti (and Si) to
C, the strength of the Ti-C covalent bond is increased. The differences between
the electronic and crystal structures of Ti4SiC3 and Ti3SiC2 are discussed in
relation to the number of Si layers per Ti layer in the two systems and the
corresponding change of materials properties.Comment: 12 pages, 7 figures, 1 tabl
Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite
We report resonant inelastic x-ray scattering (RIXS) excited by circularly
polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate
that crystal field excitations, as expected for localized systems, dominate the
RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms
of spin-resolved partial density of states, which has been the standard
approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance
which we attribute to the absence of metallic core hole screening in the
insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is
interpreted as an effect of longer scattering time that enables spin-lattice
core hole relaxation via magnons and phonons occurring on a femtosecond time
scale.Comment: 7 pages, 2 figures,
http://link.aps.org/doi/10.1103/PhysRevB.74.17240
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