How robust is the association between youth unemployment and later mental health? An analysis of longitudinal data from English schoolchildren

BACKGROUND: Several studies show that youth unemployment is associated with worse mental health later in life. However, existing studies report results for only one model, or a few models, and use regression adjustment to support causal claims. We use two novel methods to address these gaps in the literature. METHODS: We use data from Next Steps, a cohort study of English schoolchildren who entered the labour market in the aftermath of the 2008-2009 global financial crisis, and measure mental health using the 12-item General Health Questionnaire (GHQ-12) at age 25. We use specification curve analysis and a negative control outcome design (a form of placebo test) to test whether associations between youth unemployment and later GHQ-12 scores are sensitive to model specification or are likely to be confounded by unobserved factors. RESULTS: We find that the association between unemployment and later GHQ-12 is qualitatively similar across 99.96% of the 120 000 models we run. Statistically significant associations with two placebo outcomes, height and patience, are not present when regression adjustments are made. CONCLUSIONS: There is clear evidence that youth unemployment is related to later mental health, and some evidence that this cannot be easily explained by unobserved confounding

Stable dynamics in forced systems with sufficiently high/low forcing frequency

We consider a class of parametrically forced Hamiltonian systems with one-and-a-half degrees of freedom and study the stability of the dynamics when the frequency of the forcing is relatively high or low. We show that, provided the frequency of the forcing is sufficiently high, KAM theorem may be applied even when the forcing amplitude is far away from the perturbation regime. A similar result is obtained for sufficiently low frequency forcing, but in that case we need the amplitude of the forcing to be not too large; however we are still able to consider amplitudes of the forcing which are outside of the perturbation regime. Our results are illustrated by means of numerical simulations for the system of a forced cubic oscillator. In addition, we find numerically that the dynamics are stable even when the forcing amplitude is very large (beyond the range of validity of the analytical results), provided the frequency of the forcing is taken correspondingly low

Beyond von-Neumann computing with nanoscale phase-change memory devices

OnlineOpen ArticleThis is the final version of the article. Available from the publisher via the DOI in this record.Historically, the application of phase-change materials and devices has been limited to the provision of non-volatile memories. Recently however the potential has been demonstrated for using phase-change devices as the basis for new forms of brain-like computing, by exploiting their multi-level resistance capability to provide electronic mimics of biological synapses. Here we exploit a different and previously under-explored property also intrinsic to phase-change materials and devices, namely accumulation, to demonstrate that nanoscale electronic phase-change devices can also provide a powerful form of arithmetic computing. We carry out complicated arithmetic operations, including parallel factorization and fractional division, using simple nanoscale phase-change cells that process and store data simultaneously and at the same physical location, promising a most efficient and effective means for implementing 'beyond von-Neumann' computing. We also show that this same accumulation property can be used to provide a particularly simple form phase-change integrate-and-fire 'neuron' which, by combining both phase-change synapse and neuron electronic mimics, potentially opens up a route to the realization of all-phase-change neuromorphic processing.The authors gratefully acknowledge EPSRC for grant funding (EP/ F015046/1). They also would like to thank Dr. A Pauza, formerly of Plasmon Data Systems Ltd, for help in preparation of the GST samples. Professor Peter Ashwin from the University of Exeter is also acknowledged for helpful discussions and guidance in the formulation of the GCA simulator. The authors are also very grateful to Mr. David Anderson of the University of Exeter for valuable assistance with the lithography of the pseudo-devices

Bicarbonate induces high-level resistance to the human antimicrobial peptide LL-37 in Staphylococcus aureus small colony variants

Objectives: Staphylococcus aureus small colony variants (SCVs) cause persistent infections and are resistant to cationic antibiotics. Antimicrobial peptides (AMPs) have been suggested as promising alternatives for treating antibiotic-resistant bacteria. We investigated the capacity of the human cationic AMP LL-37 to kill SCVs in the presence of physiological concentrations of bicarbonate, which are reported to alter bacterial membrane permeability and change resistance of bacteria to AMPs. Methods: MBCs of LL-37 for S. aureus SCVs with mutations in different genes in the presence and absence of bicarbonate were determined. Results: In the absence of bicarbonate, SCVs of S. aureus strains LS-1 and 8325-4 had the same level of resistance to LL-37 as the parental strain (8 mg/L). In the presence of bicarbonate, hemB, menD and aroD SCVs of LS-1 had high-level resistance to LL-37 (≥128 mg/L) compared with the parental strain (16 mg/L). However, only the aroD SCV of strain 8324-5 showed high-level resistance. 8325-4 harbours mutations in two genes, tcaR and rsbU, which are involved in antimicrobial sensing and the stress response, respectively. When rsbU was repaired in 8325-4 it displayed high-level resistance to LL-37 in the presence of bicarbonate. This phenotype was lost when tcaR was also repaired, demonstrating that RsbU and TcaR are involved in LL-37 resistance in the presence of bicarbonate. Conclusions: S. aureus SCVs would be resistant to high concentrations of LL-37 in niches where there are physiological concentrations of bicarbonate and therefore this AMP may not be effective in combating SCVs

Density dependence and interspecific interactions between arbuscular mycorrhizal fungi mediated plant growth, glomalin production, and sporulation

Functional differences between the arbuscular mycorrhizal fungi Glomus intraradices Schenk and Smith and Scutellospora heterogama Nicolson and Gerdemann as they affect Persea americana Mill. growth, glomalin, and fungal sporulation were examined by varying the composition and relative density of the two fungi over a gradient of available phosphorus (P). The plant benefit provided by these mycorrhizal fungi together was not a simple sum of the benefits pro-vided by each fungus in monoculture at its respective density. Glomus intraradices and S. heterogama interacted to reduce plant growth rates and uptake of P, zinc (Zn), and iron (Fe) relative to plants inoculated with G. intraradices alone. Thus, for plant growth and nutrition, no evidence for functional complementarity was detected. Instead, interspecific interactions between mycorrhizal fungi resulted in a negative feedback on plants. Under high available P, fungal functional differences were reduced, whereas the overall difference between mycorrhizal and nonmycorrhizal plants was greatest. Overall, S. heterogama produced more glomalin than did G. intraradices. In a mixture, sporulation of the inferior mutualist, S. heterogama, was lower than that of the superior mutualist, G. intraradices, but interspecific fungal interactions increased the sporulation of both fungi. Despite the negative impact of interspecific interactions on plants, supporting multiple arbuscular mycorrhizal fungi was of greater benefit than being nonmycorrhizal. © 2007 NRC

Communication aids in the classroom: the views of education staff and speech and language therapists involved with the Communication Aids Project

The findings presented in this paper are part of an independent evaluation study of the Communication Aids Project (CAP). The study was carried out between July 2003 and April 2004 and looked at the impact of CAP on children receiving communication aids and evaluated the CAP strategy of assessment and delivery. In this paper the views of education staff and speech and language therapists who were working with communication aid users in school are presented. The professionals who were interviewed provided positive feedback on the existence of CAP, on the assessment for the communication aid, particularly where the use of the aid in the classroom was considered, and on the children's increased participation in classroom and learning activities since receiving the aid. They also highlighted the issue of managing parents' expectations regarding the use of aids and the value of and need for continued training for professionals working with communication aids in the classroom. The authors of this article, Jannet Wright, senior lecturer, Chris Donlan, senior lecturer, Caroline Newton, lecturer, and Michael Clarke, lecturer, from University College London; Claire Lister, from the Institute of Child Health, London; and Jasmina Cherguit, assistant psychologist, draw upon their findings to develop recommendations for future policy, practice and professional development

Parents' expectations and perceptions concerning the provision of communication aids by the Communication Aids Project (CAP)

This paper reports findings from part of an evaluation study of the Communication Aids Project (CAP), a government-funded project in England which provided communication aids to school-aged children. The paper focuses on parents'views of the CAP process and the impact of the aid. Fourteen parents were interviewed twice over the telephone: once before or just as their children received communication aids and again six to eight weeks later. Parents expressed satisfaction with the impact of the aid on their children's lives and showed they had realistic expectations concerning potential short- and long-term benefits. They raised two main concerns regarding the provision of aids, namely the timescale involved and access to accurate information and advice

Communication aids in the classroom: the views of education staff and speech and language therapists involved with the Communication Aids Project

The findings presented in this paper are part of an independent evaluation study of the Communication Aids Project (CAP). The study was carried out between July 2003 and April 2004 and looked at the impact of CAP on children receiving communication aids and evaluated the CAP strategy of assessment and delivery. In this paper the views of education staff and speech and language therapists who were working with communication aid users in school are presented. The professionals who were interviewed provided positive feedback on the existence of CAP, on the assessment for the communication aid, particularly where the use of the aid in the classroom was considered, and on the children's increased participation in classroom and learning activities since receiving the aid. They also highlighted the issue of managing parents' expectations regarding the use of aids and the value of and need for continued training for professionals working with communication aids in the classroom. The authors of this article, Jannet Wright, senior lecturer, Chris Donlan, senior lecturer, Caroline Newton, lecturer, and Michael Clarke, lecturer, from University College London; Claire Lister, from the Institute of Child Health, London; and Jasmina Cherguit, assistant psychologist, draw upon their findings to develop recommendations for future policy, practice and professional development

Ultraluminous Infrared Galaxies

At luminosities above ~10^{11} L_sun, infrared galaxies become the dominant population of extragalactic objects in the local Universe (z < 0.5), being more numerous than optically selected starburst and Seyfert galaxies, and QSOs at comparable bolometric luminosity. At the highest luminosities, ultraluminous infrared galaxies (ULIGs: L_ir > 10^{12} L_sun), outnumber optically selected QSOs by a factor of ~1.5-2. All of the nearest ULIGs (z < 0.1) appear to be advanced mergers that are powered by both a circumnuclear starburst and AGN, both of which are fueled by an enormous concentration of molecular gas (~10^{10} M_sun) that has been funneled into the merger nucleus. ULIGs may represent a primary stage in the formation of massive black holes and elliptical galaxy cores. The intense circumnuclear starburst that accompanies the ULIG phase may also represent a primary stage in the formation of globular clusters, and the metal enrichment of the intergalactic medium by gas and dust expelled from the nucleus due to the combined forces of supernova explosions and powerful stellar winds.Comment: LaTex, 6 pages with 4 embedded .eps figures. Postscript version plus color plates available at http://www.ifa.hawaii.edu/users/sanders/astroph/s186/plates.html To appear in "Galaxy Interactions at Low and High Redshift" IAU Symposium 186, Kyoto, Japan, eds. J.E. Barnes and D.B. Sander