2,282 research outputs found
Life-course and cohort trajectories of mental health in the UK, 1991â2008 â A multilevel ageâperiodâcohort analysis
There is ongoing debate regarding the shape of life-course trajectories in mental health. Many argue the relationship is U-shaped, with mental health declining with age to mid-life, then improving. However, I argue that these models are beset by the ageâperiodâcohort (APC) identification problem, whereby age, cohort and year of measurement are exactly collinear and their effects cannot be meaningfully separated. This means an apparent life-course effect could be explained by cohorts. This paper critiques two sets of literature: the substantive literature regarding life-course trajectories in mental health, and the methodological literature that claims erroneously to have âsolvedâ the APC identification problem statistically (e.g. using Yang and Land's Hierarchical APCâHAPC-model). I then use a variant of the HAPC model, making strong but justified assumptions that allow the modelling of life-course trajectories in mental health (measured by the General Health Questionnaire) net of any cohort effects, using data from the British Household Panel Survey, 1991â2008. The model additionally employs a complex multilevel structure that allows the relative importance of spatial (households, local authority districts) and temporal (periods, cohorts) levels to be assessed. Mental health is found to increase throughout the life-course; this slows at mid-life before worsening again into old age, but there is no evidence of a U-shape â I argue that such findings result from confounding with cohort processes (whereby more recent cohorts have generally worse mental health). Other covariates were also evaluated; income, smoking, education, social class, urbanity, ethnicity, gender and marriage were all related to mental health, with the latter two in particular affecting life-course and cohort trajectories. The paper shows the importance of understanding APC in life-course research generally, and mental health research in particular
Targeting of anionic membrane species by lanthanide(III) complexes: towards improved MRI contrast agents for apoptosis
No abstract available
Turbulence-chemistry interaction in lean premixed hydrogen combustion
This paper presents three-dimensional direct numerical simulations of lean premixed hydrogen flames at an equivalence ratio of varphi=0.4 over a range of turbulence levels from Ka=1 - 36. The simulations form part of a larger effort to construct a DNS database that can be used by the community for model construction and validation. We have focussed on producing well-resolved simulations at conditions representative of atmospheric laboratory-scale flames. After an overview of phenomenological trends with increasing Karlovitz number, we examine the factors that lead to an observed decorrelation between fuel consumption and heat release in the flame at Ka=36. We show that in this flame the fuel consumption is greatly enhanced in regions of positive curvature. We also show that the radical pool is enriched throughout the entire flame as \Ka is increased. In particular, we identify three reactions that, driven by high molar concentrations of radicals at low temperatures, are responsible for high levels of heat release away from regions of fuel consumption, thereby accounting for the observed decorrelation between fuel consumption and heat release
Addressing the clumsiness loophole in a Leggett-Garg test of macrorealism
The rise of quantum information theory has lent new relevance to experimental
tests for non-classicality, particularly in controversial cases such as
adiabatic quantum computing superconducting circuits. The Leggett-Garg
inequality is a "Bell inequality in time" designed to indicate whether a single
quantum system behaves in a macrorealistic fashion. Unfortunately, a violation
of the inequality can only show that the system is either (i)
non-macrorealistic or (ii) macrorealistic but subjected to a measurement
technique that happens to disturb the system. The "clumsiness" loophole (ii)
provides reliable refuge for the stubborn macrorealist, who can invoke it to
brand recent experimental and theoretical work on the Leggett-Garg test
inconclusive. Here, we present a revised Leggett-Garg protocol that permits one
to conclude that a system is either (i) non-macrorealistic or (ii)
macrorealistic but with the property that two seemingly non-invasive
measurements can somehow collude and strongly disturb the system. By providing
an explicit check of the invasiveness of the measurements, the protocol
replaces the clumsiness loophole with a significantly smaller "collusion"
loophole.Comment: 7 pages, 3 figure
Preâservice teacher training and special educational needs in England 1970â2008: is government learning the lessons of the past or is it experiencing a groundhog day?
The paper outlines the findings from a literature review of the English governmentâs response to the issue of training preâservice teachers in the delivery of effective special educational needs support. The reviewâs findings detail that although educational practice in mainstream classrooms has changed considerably since the 1970s the training of preâservice teachers with regards to special educational needs has seemingly changed very little. The paper argues that the government needs to reâthink radically its policy of inclusion to ensure that a coherent plan is formulated which enables higher education institutionsâ initial teacher training programmes to train students who are competent and confident in their abilities to work with children with special educational needs and/or disabilities
Charm Quark Contribution to K+ -> pi+ nu anti-nu at Next-to-Next-to-Leading Order
We calculate the complete NNLO QCD corrections to the charm contribution of
the rare decay K+ -> pi+ nu nu-bar. We encounter several new features, which
were absent in lower orders. We discuss them in detail and present the results
for the 2-loop matching conditions of the Wilson coefficients, the 3-loop
anomalous dimensions, and the 2-loop matrix elements of the relevant operators
that enter the NNLO renormalization group analysis of the Z-penguin and the
electroweak box contribution. The inclusion of the NNLO QCD corrections leads
to a significant reduction of the theoretical uncertainty from 9.8% down to
2.4% in the relevant parameter Pc, implying the leftover scale uncertainties in
BR(K+ -> pi+ nu nu-bar) and in the determination of |V_td|, sin(2 beta), and
gamma from the K -> pi nu nu system to be 1.3%, 1.0%, 0.006, and 1.2 degrees,
respectively. For the charm quark MSbar mass mc=(1.30+-0.05) GeV and |V_us|=
0.2248 the NLO value Pc=0.37+-0.06 is modified to Pc=0.38+-0.04 at the NNLO
level with the latter error fully dominated by the uncertainty in mc. We
present tables for Pc as a function of mc and alphas(MZ) and a very accurate
analytic formula that summarizes these two dependences as well as the dominant
theoretical uncertainties. Adding the recently calculated long-distance
contributions we find BR(K+ -> pi+ nu nu-bar)=(8.0+-1.1)*10^-11 with the
present uncertainties in mc and the Cabibbo-Kobayashi-Maskawa elements being
the dominant individual sources in the quoted error. We also emphasize that
improved calculations of the long-distance contributions to K+ -> pi+ nu nu-bar
and of the isospin breaking corrections in the evaluation of the weak current
matrix elements from K+ -> pi0 e+ nu would be valuable in order to increase the
potential of the two golden K -> pi nu nu decays in the search for new physics.Comment: 74 pages, 28 figures. Erratum added: We correct the treatment of
anomalous triangle diagrams. The associated numerical correction is below a
permille; v3: Typographical mistakes in (108), (111) and (112) corrected.
Thanks to Xu Feng for pointing them out. Numerical results unchange
The increasing activity of a vascular ultrasound service
Objectives:To examine the change in activity of a vascular ultrasound service over 7 years.Design:Retrospective review.Setting:Vascular studies unit, University hospital.Method:Audit of the number of vascular ultrasound tests carried out over the last 7 years using a prospective computerised database.Results:Data shows that the overall workload has tripled over the 7-year period. In addition the complexity of investigations has increased during this time. The number of carotid scans has increased four-fold while the number of graft surveillance scans and vein scans has increased seven-fold. Assessment of lower limb arteries has developed from simple pressure measurements to detailed ultrasound scans and, as a consequence, the number of diagnostic angiograms has fallen by 75%. The factors that have influenced these changes are discussed.Conclusion:There has been an important increase in the role of colour Doppler ultrasound as it becomes the âfirst lineâ vascular diagnostic test. However this trend can only continue if vascular ultrasound services are appropriately resourced. It is therefore essential to maintain an efficient audit system
Real-time PCR based on SYBR-Green I fluorescence: An alternative to the TaqMan assay for a relative quantification of gene rearrangements, gene amplifications and micro gene deletions
BACKGROUND:
Real-time PCR is increasingly being adopted for RNA quantification and genetic analysis. At present the most popular real-time PCR assay is based on the hybridisation of a dual-labelled probe to the PCR product, and the development of a signal by loss of fluorescence quenching as PCR degrades the probe. Though this so-called 'TaqMan' approach has proved easy to optimise in practice, the dual-labelled probes are relatively expensive.
RESULTS:
We have designed a new assay based on SYBR-Green I binding that is quick, reliable, easily optimised and compares well with the published assay. Here we demonstrate its general applicability by measuring copy number in three different genetic contexts; the quantification of a gene rearrangement (T-cell receptor excision circles (TREC) in peripheral blood mononuclear cells); the detection and quantification of GLI, MYC-C and MYC-N gene amplification in cell lines and cancer biopsies; and detection of deletions in the OPA1 gene in dominant optic atrophy.
CONCLUSION:
Our assay has important clinical applications, providing accurate diagnostic results in less time, from less biopsy material and at less cost than assays currently employed such as FISH or Southern blotting
Leionema lamprophyllum subsp. fractum (Rutaceae); a new and highly restricted taxon from the Hunter Valley of New South Wales
A new subspecies of Leionema lamprophyllum, formerly included in L. lamprophyllum subsp. obovatum F.M.Anderson, is here described as new. Currently known from fewer than 50 individuals, the new subsp. is highly restricted and warrants a conservation risk code of at least Endangered. An illustration of the new taxon, notes on its distribution and habitat, and a key to all four subspecies of L. lamprophyllum are also provided
Using shrinkage in multilevel models to understand intersectionality: a simulation study and a guide for best practice
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