617 research outputs found
Towards determining the neutrino mass hierarchy:weak lensing and galaxy clustering forecasts with baryons and intrinsic alignments
The capacity of Stage IV lensing surveys to measure the neutrino mass sum and
differentiate between the normal and inverted mass hierarchies depends on the
impact of nuisance parameters describing small-scale baryonic astrophysics and
intrinsic alignments. For a Euclid-like survey, we perform the first combined
weak lensing and galaxy clustering Fisher analysis with baryons, intrinsic
alignments, and massive neutrinos for both hierarchies. We use a matter power
spectrum generated from a halo model that captures the impact of baryonic
feedback and adiabatic contraction. For weak lensing, we find that baryons
cause severe degradation to forecasts of the neutrino mass sum, ,
approximately doubling . We show that including galaxy
clustering constraints from Euclid and BOSS, and cosmic microwave background
(CMB) Planck priors, can reduce this degradation to to 9% and
16% for the normal and inverted hierarchies respectively. The combined
forecasts, and
, preclude a meaningful distinction
of the hierarchies but could be improved upon with future CMB priors on
and information from neutrinoless double beta decay to achieve a 2
distinction. The effect of intrinsic alignments on forecasts is shown to be
minimal, with even experiencing mild improvements due to
information from the intrinsic alignment signal. We find that while adiabatic
contraction and intrinsic alignments will require careful calibration to
prevent significant biasing of , there is less risk presented by
feedback from energetic events like AGN and supernovae.Comment: 24 pages, 13 figures. Several minor changes to the text, and
transference of background material to appendices to match the version
published by MNRA
Exchange interaction, disorder, and stacking faults in rhombohedral graphene multilayers
We apply the mean-field Hartree Fock theory of gapped electronic states at charge neutrality in bilayer graphene to thin films of rhombohedral graphite with up to thirty layers. For the ground state, the order parameter (the separation of bands at the valley center) saturates to a constant non-zero value as the layer number increases, whereas the band gap decreases with layer number. We consider chiral symmetry breaking disorder in the form of random layer potentials and chiral preserving disorder in the form of random values of the interlayer coupling. The former reduces the magnitude of the mean band gap whereas the latter has a negligible effect, which is due to self-averaging within a film with a large number of layers. We determine the ground state in the presence of an individual stacking fault which results in two pairs of low-energy bands and we identify two separate order parameters. One of them determines the band gap at zero temperature, the other determines the critical temperature leading, overall, to a temperature dependence of the band gap that is distinct to that of pristine rhombohedral graphite. In the presence of stacking faults, each individual rhombohedral section with m layers contributes a pair of low-energy flat bands producing a peak in the Berry curvature located at a characteristic m-dependent wave vector. The Chern number per spin-valley flavor for the filled valence bands in the ground state is equal in magnitude to the total number of layers divided by two, the same value as for pristine rhombohedral graphite
The impact of baryons on the sensitivity of dark energy measurements
Baryonic effects on large-scale structure, if not accounted for, can
significantly bias dark energy constraints. As the detailed physics of the
baryons is not yet well-understood, correcting for baryon effects introduces
additional parameters which must be marginalized over, increasing the
uncertainties on the inferred cosmological parameters. Forthcoming weak lensing
surveys are aiming for percent-level precision on the dark energy equation of
state, so the problem must be thoroughly examined. We use a halo model with
analytic modifications which capture the impact of adiabatic contraction of
baryons and feedback on the matter power spectrum, and generalize the
Navarro-Frenk-White profile to account for a possible inner core. A Fisher
analysis predicts degradations of 40% in the - Figure of Merit for a
Euclid-like survey, and up to 80% for other cosmological parameters. We
forecast potential inner core constraints of a few , while for a
fixed inner core, adiabatic concentration and feedback parameters are
constrained to a few percent. We explore the scales where baryons and dark
energy contribute most to the Fisher information, finding that probing to
increasingly non-linear scales does little to reduce degradation. Including
external baryon information improves our forecasts, but limiting degradation to
1% requires strong priors. Adding Planck cosmic microwave background priors
improves the Figure of Merit by a factor of 2.7 and almost completely recovers
the individual marginalized errors on and . We also quantify the
calibration of baryon modelling required to reduce biases of dark energy
forecasts to acceptable levels for forthcoming lensing surveys.Comment: 20 pages, 17 figures. Several minor changes in the text to match
version accepted for publication in MNRA
Understanding and improving the care pathway for children with autism
Purpose: To describe current care pathways for children with autism including enablers and barriers, as experienced by health professionals, education professionals, and families in South Wales, UK.
Design/methodology/approach: A mixed-methods approach using focus group discussions, creative writing workshops and visualisation using rich pictures.
Findings: The experiences of the care pathways differed significantly across the three groups. Health professionals described the most rigidly-structured pathways, with clear entry points and outcomes. Education professionals and parents described more complex and confusing pathways, with parents assuming the responsibility of coordinating the health and education activity in a bid to link the two independent pathways. All three groups identified enablers, although these differed across the groups. The barriers were more consistent across the groups (e.g. poor communication, missing information, lack of transparency, limited post diagnosis services and access to services based on diagnosis rather than need).
Practical implications: This research could inform the design of new services which are premised on multi-agency and multi-disciplinary working to ensure children with ASD receive joined up services and support.
Originality/value: Although this study did not represent all professional groups or all experiences of autism, we examined three different perspectives of the ASD pathway. In addition, we triangulated high-level process maps with rich pictures and creative writing exercises, which allowed us to identify specific recommendations to improve integration and reduce duplication and gaps in provision
Complete Genome Sequence of \u3ci\u3eLactobacillus buchneri\u3c/i\u3e NRRL B-30929, a Novel Strain from a Commercial Ethanol Plant
Lactobacillus buchneri strain NRRL B-30929 was a contaminant obtained from a commercial ethanol fermentation. This facultative anaerobe is unique because of its rapid growth on xylose and simultaneous fermentation of xylose and glucose. The strain utilizes a broad range of carbohydrate substrates and possesses a high tolerance to ethanol and other stresses, making it an attractive candidate for bioconversion of biomass substrates to various bioproducts. The genome sequence of NRRL B-30929 will provide insight into the unique properties of this lactic acid bacterium
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Metatranscriptomic Sequencing of a Cyanobacterial Soil-Surface Consortium with and without a Diverse Underlying Soil Microbiome.
Soil surface consortia are easily observed and sampled, allowing examination of their interactions with soil microbiomes. Here, we present metatranscriptomic sequences from Dark Green 1 (DG1), a cyanobacterium-based soil surface consortium, in the presence and absence of an underlying soil microbiome and/or urea
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Shotgun metagenome data of a defined mock community using Oxford Nanopore, PacBio and Illumina technologies.
Metagenomic sequence data from defined mock communities is crucial for the assessment of sequencing platform performance and downstream analyses, including assembly, binning and taxonomic assignment. We report a comparison of shotgun metagenome sequencing and assembly metrics of a defined microbial mock community using the Oxford Nanopore Technologies (ONT) MinION, PacBio and Illumina sequencing platforms. Our synthetic microbial community BMock12 consists of 12 bacterial strains with genome sizes spanning 3.2-7.2 Mbp, 40-73% GC content, and 1.5-7.3% repeats. Size selection of both PacBio and ONT sequencing libraries prior to sequencing was essential to yield comparable relative abundances of organisms among all sequencing technologies. While the Illumina-based metagenome assembly yielded good coverage with few misassemblies, contiguity was greatly improved by both, Illumina + ONT and Illumina + PacBio hybrid assemblies but increased misassemblies, most notably in genomes with high sequence similarity to each other. Our resulting datasets allow evaluation and benchmarking of bioinformatics software on Illumina, PacBio and ONT platforms in parallel
Draft genome sequence of Frankia sp. strain DC12, an atypical, noninfective, ineffective isolate from Datisca cannabina
Frankia sp. strain DC12, isolated from root nodules of Datisca cannabina, is a member of the fourth lineage of Frankia, which is unable to reinfect actinorhizal plants. Here, we report its 6.88-Mbp high-quality draft genome sequence, with a G+C content of 71.92% and 5,858 candidate protein-coding genes
Are drug treatment services only for 'thieving junkie scumbags'? Drug users and the management of stigmatised identities.
This article uses qualitative interviews with 53 problematic drug users who had dropped out of treatment in England, UK to explore how they describe the stigmatisation of drug users and drug services. It discusses the construction of the category of the junkie through its association with un-controlled heroin use and criminality. It shows how some drug users carefully manage information about their discreditable identities by excluding themselves from this category, while acknowledging its validity for other drug users. The junkie
identity was generally seen as shameful and therefore to be avoided, although it holds attractions for some drug users. For many of the interviewees, entry to treatment risked exposing their own activities as shaming, as they saw treatment as being a place that was populated by junkies and where it becomes more difficult to manage discreditable information. The treatment regime, e.g. the routine of supervised consumption of methadone,was itself seen by some as stigmatising and was also seen as hindering progress to the desired ‘normal’ life of conventional employment. Participation in the community of users of both drugs and drug services was perceived as potentially damaging to the prospects of recovery. This emphasises the importance of social capital, including links to people and opportunities outside the drug market. It also highlights the danger that using the criminal
justice system to concentrate prolific offenders in treatment may have the perverse effects of excluding other people who have drug problems and of prolonging the performance of the junkie identity within treatment services. It is concluded that treatment agencies
should address these issues, including through the provision of more drug services in mainstream settings, in order to ensure that drug services are not seen to be suitable only for one particularly stigmatised category of drug user
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