Care-experienced youth and positive development: An exploratory study into the value and use of leisure-time activities

Numerous youth development outcomes are thought to ensue from participation in ‘positive’ activities (including leisure activities), yet little is known about how care-experienced youth access and benefit from such activities. Underpinned by a positive youth development perspective and informed by the socio-ecological model, this study aimed to: (1) identify how care-experienced youth spent their leisure-time and what shaped their participation; and (2) explore how care-experienced youth think leisure-time activities contributed to their positive development

The impact of the 1783-1784 AD Laki eruption on global aerosol formation processes and cloud condensation nuclei

The 1783–1784 AD Laki flood lava eruption commenced on 8 June 1783 and released 122 Tg of sulphur dioxide gas over the course of 8 months into the upper troposphere and lower stratosphere above Iceland. Previous studies have examined the impact of the Laki eruption on sulphate aerosol and climate using general circulation models. Here, we study the impact on aerosol microphysical processes, including the nucleation of new particles and their growth to cloud condensation nuclei (CCN) using a comprehensive Global Model of Aerosol Processes (GLOMAP). Total particle concentrations in the free troposphere increase by a factor ~16 over large parts of the Northern Hemisphere in the 3 months following the onset of the eruption. Particle concentrations in the boundary layer increase by a factor 2 to 5 in regions as far away as North America, the Middle East and Asia due to long-range transport of nucleated particles. CCN concentrations (at 0.22% supersaturation) increase by a factor 65 in the upper troposphere with maximum changes in 3-month zonal mean concentrations of ~1400 cm<sup>−3</sup> at high northern latitudes. 3-month zonal mean CCN concentrations in the boundary layer at the latitude of the eruption increase by up to a factor 26, and averaged over the Northern Hemisphere, the eruption caused a factor 4 increase in CCN concentrations at low-level cloud altitude. The simulations show that the Laki eruption would have completely dominated as a source of CCN in the pre-industrial atmosphere. The model also suggests an impact of the eruption in the Southern Hemisphere, where CCN concentrations are increased by up to a factor 1.4 at 20° S. Our model simulations suggest that the impact of an equivalent wintertime eruption on upper tropospheric CCN concentrations is only about one-third of that of a summertime eruption. The simulations show that the microphysical processes leading to the growth of particles to CCN sizes are fundamentally different after an eruption when compared to the unperturbed atmosphere, underlining the importance of using a fully coupled microphysics model when studying long-lasting, high-latitude eruptions

Energy Flow in Acoustic Black Holes

We present the results of an analysis of superradiant energy flow due to scalar fields incident on an acoustic black hole. In addition to providing independent confirmation of the recent results in [5], we determine in detail the profile of energy flow everywhere outside the horizon. We confirm explicitly that in a suitable frame the energy flow is inward at the horizon and outward at infinity, as expected on physical grounds.Comment: 8 pages, 9 figures, Comments added to discussion of energy flow and introductory section abbreviate

Physical activity and children in care: A scoping review of barriers, facilitators and policy for disadvantaged youth

Background: It is argued that regular engagement in physical activity (PA) has the potential to mitigate the negative health and educational outcomes that disadvantaged children living in care frequently face. However, little is currently known about children in care’s participation in PA. This scoping review primarily aimed to identify barriers and facilitators to PA participation for children in care. Methods: The main phases of the scoping review were: (1) identifying relevant studies; (2) selecting studies based on pre-defined inclusion criteria; (3) charting the data; and (4) collating, summarising and reporting the results. All relevant studies were included in the review regardless of methodological quality and design. Results: The seven articles that met the inclusion criteria were published between 1998 and 2013 and conducted in the USA (3), England (2) and Norway (2). A social ecological model was incorporated to map results against levels of influence. Conclusions: Various factors influence PA engagement for children in care. Barriers include low self-efficacy, instability of their social environment, which impacts on schooling and maintaining friendship groups and, specific institutional practices and policies that may prevent access to PA. Before fully considering policy implications, further research with children in care is warranted in this area

Atomic and Molecular Data for Optical Stellar Spectroscopy

High-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics. Examples include studying the chemical structure and evolution of the Milky Way galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. These instruments are located at ground-based 2- to 10-m class telescopes around the world, in addition to the spectrographs with unique capabilities available at the Hubble Space Telescope. The interpretation of these spectra requires high-quality transition data for numerous species, in particular neutral and singly ionized atoms, and di- or triatomic molecules. We rely heavily on the continuous efforts of laboratory astrophysics groups that produce and improve the relevant experimental and theoretical atomic and molecular data. The compilation of the best available data is facilitated by databases and electronic infrastructures such as the NIST Atomic Spectra Database, the VALD database, or the Virtual Atomic and Molecular Data Centre (VAMDC). We illustrate the current status of atomic data for optical stellar spectra with the example of the Gaia-ESO Public Spectroscopic Survey. Data sources for 35 chemical elements were reviewed in an effort to construct a line list for a homogeneous abundance analysis of up to 100000 stars.Comment: Published 30 April 2015 in Physica Script

Spitzer Observations of Low Luminosity Isolated and Low Surface Brightness Galaxies

We examine the infrared properties of five low surface brightness galaxies (LSBGs) and compare them with related but higher surface brightness galaxies, using Spitzer Space Telescope images and spectra. All the LSBGs are detected in the 3.6 and 4.5um bands, representing the stellar population. All but one are detected at 5.8 and 8.0um, revealing emission from hot dust and aromatic molecules, though many are faint or point-like at these wavelengths. Detections of LSBGs at the far-infrared wavelengths, 24, 70, and 160um, are varied in morphology and brightness, with only two detections at 160um, resulting in highly varied spectral energy distributions. Consistent with previous expectations for these galaxies, we find that detectable dust components exist for only some LSBGs, with the strength of dust emission dependent on the existence of bright star forming regions. However, the far-infrared emission may be relatively weak compared with normal star-forming galaxies.Comment: 20 pages, 8 figures, accepted to Ap

C9orf72 repeat expansions cause neurodegeneration in Drosophila through arginine-rich proteins

An expanded GGGGCC repeat in C9orf72 is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis. A fundamental question is whether toxicity is driven by the repeat RNA itself and/or by dipeptide repeat proteins generated by repeat-associated, non-ATG translation. To address this question we developed in vitro and in vivo models to dissect repeat RNA and dipeptide repeat protein toxicity. Expression of pure repeats in Drosophila caused adult-onset neurodegeneration attributable to poly-(glycine-arginine) proteins. Thus, expanded repeats promoted neurodegeneration through neurotoxic proteins. Expression of individual dipeptide repeat proteins with a non-GGGGCC RNA sequence showed both poly-(glycine-arginine) and poly-(proline-arginine) proteins caused neurodegeneration. These findings are consistent with a dual toxicity mechanism, whereby both arginine-rich proteins and repeat RNA contribute to C9orf72-mediated neurodegeneration

A paradox of syntactic priming: why response tendencies show priming for passives, and response latencies show priming for actives

Speakers tend to repeat syntactic structures across sentences, a phenomenon called syntactic priming. Although it has been suggested that repeating syntactic structures should result in speeded responses, previous research has focused on effects in response tendencies. We investigated syntactic priming effects simultaneously in response tendencies and response latencies for active and passive transitive sentences in a picture description task. In Experiment 1, there were priming effects in response tendencies for passives and in response latencies for actives. However, when participants' pre-existing preference for actives was altered in Experiment 2, syntactic priming occurred for both actives and passives in response tendencies as well as in response latencies. This is the first investigation of the effects of structure frequency on both response tendencies and latencies in syntactic priming. We discuss the implications of these data for current theories of syntactic processing

Effect of fibre length and suspension concentration on alignment quality of discontinuous recycled carbon fibre

Recycling has been widely considered to be one of the crucial requirements for the continuous use and growth in composite material. In this paper, a hydrodynamic alignment process is devised for converting discontinuous random recycled carbon fibre into mats with a highly aligned orientation distribution. The process involves preparation of a fibre suspension stock, fibre alignment via a nozzle, filtration and aligned mat treatment. The aligned mat allows composites with higher volume content to be manufactured at lower moulding pressure thus keeping degradation of fibre length to a minimum. In the past, alignment processes have been focused on fibres shorter than 5mm as they provide good dispersion quality. In the existing work, an attempt was made to use longer fibres in the alignment process as route to potential enhancement of composite performance. In addition, fibre concentration in the suspension was increased in order to increase the process yield rate. The effect of using longer fibre lengths and more concentrated suspension on alignment quality is reported in this paper. Furthermore, the relationship between nozzle geometry and alignment quality is also investigated. Finally the mechanical properties of a composite laminate made from 3mm recycled fibre are explored

High Metallicity Mg II Absorbers in the z < 1 Lyman alpha Forest of PKS 0454+039: Giant LSB Galaxies?

We report the discovery of two iron-group enhanced high-metallicity Mg II absorbers in a search through 28 Lyman Alpha forest clouds along the PKS 0454+039 sight line. Based upon our survey and the measured redshift number densities of W_r(MgII) <= 0.3 A absorbers and Lyman Alpha absorbers at z ~ 1, we suggest that roughly 5% of Lyman Alpha absorbers at z < 1 will exhibit "weak" Mg II absorption to a 5-sigma W_r(2796) detection limit of 0.02 A. The two discovered absorbers, at redshifts z = 0.6248 and z = 0.9315, have W_r(Lya) = 0.33 and 0.15 A, respectively. Based upon photoionization modeling, the H I column densities are inferred to be in the range 15.8 <= log N(HI) <= 16.8 cm^-2. For the z = 0.6428 absorber, if the abundance pattern is solar, then the cloud has [Fe/H] > -1; if its gas-phase abundance follows that of depleted clouds in our Galaxy, then [Fe/H] > 0 is inferred. For the z = 0.9315 absorber, the metallicity is [Fe/H] > 0, whether the abundance pattern is solar or suffers depletion. Imaging and spectroscopic studies of the PKS 0454+039 field reveal no candidate luminous objects at these redshifts. We discuss the possibility that these Mg II absorbers may arise in the class of "giant" low surface brightness galaxies, which have [Fe/H] >= -1, and even [Fe/H] >= 0, in their extended disks. We tentatively suggest that a substantial fraction of these "weak" Mg II absorbers may select low surface brightness galaxies out to z ~ 1.Comment: Accepted The Astrophysical Journal; 25 pages; 6 encapsulated figure