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Mental Health of Children and Young People in England, 2017: Trends and characteristics
This survey series provides England’s best source of data on trends in child mental health. Emotional, behavioural, hyperactivity, and other types of mental disorder were assessed in 5 to 15 year olds in 1999, 5 to 16 year olds in 2004, and 5 to 19 year olds in 2017.
One in eight (12.8%) 5 to 19 year olds had a mental disorder when assessed in 2017. Rates were similar in boys and girls. Data for 5 to 15 year olds show a slight upward trend over time in the prevalence of emotional disorders.Rates for behavioural, hyperactivity and other disorders have remained broadly stable
Estimating Column Density in Molecular Clouds with FIR and Sub-mm Emission Maps
We have used a numerical simulation of a turbulent cloud to synthesize maps
of the thermal emission from dust at a variety of far-IR and sub-mm
wavelengths. The average column density and external radiation field in the
simulation is well matched to clouds such as Perseus and Ophiuchus. We use
pairs of single-wavelength emission maps to derive the dust color temperature
and column density, and we compare the derived column densities with the true
column density. We demonstrate that longer wavelength emission maps yield less
biased estimates of column density than maps made towards the peak of the dust
emission spectrum. We compare the scatter in the derived column density with
the observed scatter in Perseus and Ophiuchus. We find that while in Perseus
all of the observed scatter in the emission-derived versus the
extinction-derived column density can be attributed to the flawed assumption of
isothermal dust along each line of sight, in Ophiuchus there is additional
scatter above what can be explained by the isothermal assumption. Our results
imply that variations in dust emission properties within a molecular cloud are
not necessarily a major source of uncertainty in column density measurements.Comment: Accepted to ApJ Letter
Correlations and fluctuations of a confined electron gas
The grand potential and the response of a phase-coherent confined noninteracting electron gas depend
sensitively on chemical potential or external parameter . We compute
their autocorrelation as a function of , and temperature. The result
is related to the short-time dynamics of the corresponding classical system,
implying in general the absence of a universal regime. Chaotic, diffusive and
integrable motions are investigated, and illustrated numerically. The
autocorrelation of the persistent current of a disordered mesoscopic ring is
also computed.Comment: 12 pages, 1 figure, to appear in Phys. Rev.
Early quantitative evidence on the impact of the pathways to work pilots
Since October 2003 the Department for Work and Pensions (DWP) has been piloting reforms in England, Scotland and Wales which provide greater support alongside greater obligations to encourage many new claimants of incapacity benefits to move into paid work.
The Pathways to Work package of reforms includes: a series of usually mandatory workfocused interviews; programmes designed to boost claimants' prospects of being able to work; and increased financial incentives for individuals to enter paid employment. As part of a quantitative assessment of the impact of the programme, a telephone survey of those making an initial enquiry to Jobcentre Plus about claiming incapacity benefits was conducted in both pilot and comparison areas before and after the pilots were implemented.
This report focuses on the differences in some early quantitative outcomes between Pathways and non-Pathways areas. Two empirical techniques are used to investigate the early impact of the pilots on employment, earnings, receipt of incapacity benefits, and a potential indicator of the extent to which individuals' health affects their everyday activities. The analysis was undertaken by researchers at the Institute for Fiscal Studies and the telephone interviews were undertaken by the National Centre for Social Research.
All these findings are preliminary: more comprehensive analysis will be conducted in later stages of the evaluation. This report analyses outcomes at a time shortly after the pilots started. Further analysis of outcomes will assess Pathways to Work using survey and administrative data from a later cohort and will examine outcomes over a longer period of time
Grazing-angle scattering of electromagnetic waves in gratings with varying mean parameters: grating eigenmodes
A highly unusual pattern of strong multiple resonances for bulk
electromagnetic waves is predicted and analysed numerically in thick periodic
holographic gratings in a slab with the mean permittivity that is larger than
that of the surrounding media. This pattern is shown to exist in the geometry
of grazing-angle scattering (GAS), that is when the scattered wave (+1
diffracted order) in the slab propagates almost parallel to the slab (grating)
boundaries. The predicted resonances are demonstrated to be unrelated to
resonant generation of the conventional guided modes of the slab. Their
physical explanation is associated with resonant generation of a completely new
type of eigenmodes in a thick slab with a periodic grating. These new slab
eigenmodes are generically related to the grating; they do not exist if the
grating amplitude is zero. The field structure of these eigenmodes and their
dependence on structural and wave parameters is analysed. The results are
extended to the case of GAS of guided modes in a slab with a periodic groove
array of small corrugation amplitude and small variations in the mean thickness
of the slab at the array boundaries.Comment: 16 pages, 6 figure
Examining the mortality effects of the Irish National Smoking Ban.
Secondhand smoke causes disease and death in those exposed, with cardiovascular and respiratory problems as the most likely outcomes. The purpose of this study was to examine the mortality effects of the Irish national smoking ban of 2004
Ultrafast Charge Transfer at a Quantum Dot/2D Materials Interface Probed by Second Harmonic Generation
Hybrid quantum dot (QD) / transition metal dichalcogenide (TMD)
heterostructures are attractive components of next generation optoelectronic
devices, which take advantage of the spectral tunability of QDs and the charge
and exciton transport properties of TMDs. Here, we demonstrate tunable
electronic coupling between CdSe QDs and monolayer WS using variable length
alkanethiol ligands on the QD surface. Using femtosecond time-resolved second
harmonic generation (SHG) microscopy, we show that electron transfer from
photoexcited CdSe QDs to single-layer WS occurs on ultrafast (50 fs - 1 ps)
timescales. Moreover, in the samples exhibiting the fastest charge transfer
rates ( 50 fs) we observed oscillations in the time-domain signal
corresponding to an acoustic phonon mode of the donor QD, which coherently
modulates the SHG response of the underlying WS layer. These results reveal
surprisingly strong electronic coupling at the QD/TMD interface and demonstrate
the usefulness of time-resolved SHG for exploring ultrafast
electronic-vibrational dynamics in TMD heterostructures
Protoplanetary Disk Turbulence Driven by the Streaming Instability: Non-Linear Saturation and Particle Concentration
We present simulations of the non-linear evolution of streaming instabilities
in protoplanetary disks. The two components of the disk, gas treated with grid
hydrodynamics and solids treated as superparticles, are mutually coupled by
drag forces. We find that the initially laminar equilibrium flow spontaneously
develops into turbulence in our unstratified local model. Marginally coupled
solids (that couple to the gas on a Keplerian time-scale) trigger an upward
cascade to large particle clumps with peak overdensities above 100. The clumps
evolve dynamically by losing material downstream to the radial drift flow while
receiving recycled material from upstream. Smaller, more tightly coupled solids
produce weaker turbulence with more transient overdensities on smaller length
scales. The net inward radial drift is decreased for marginally coupled
particles, whereas the tightly coupled particles migrate faster in the
saturated turbulent state. The turbulent diffusion of solid particles, measured
by their random walk, depends strongly on their stopping time and on the
solids-to-gas ratio of the background state, but diffusion is generally modest,
particularly for tightly coupled solids. Angular momentum transport is too weak
and of the wrong sign to influence stellar accretion. Self-gravity and
collisions will be needed to determine the relevance of particle overdensities
for planetesimal formation.Comment: Accepted for publication in ApJ (17 pages). Movies of the simulations
can be downloaded at http://www.mpia.de/~johansen/research_en.ph
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