23 research outputs found

    The evolution of post-starburst galaxies from z=2 to 0.5

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    We present the evolution in the number density and stellar mass functions of photometrically selected post-starburst galaxies in the UKIDSSUltraDeep Survey,with redshifts of 0.510. We find that this transitionary species of galaxy is rare at all redshifts, contributing ∼5 per cent of the total population at z ∼ 2, to <1 per cent by z ∼ 0.5. By comparing the mass functions of quiescent galaxies to post-starburst galaxies at three cosmic epochs, we show that rapid quenching of star formation can account for 100 per cent of quiescent galaxy formation, if the post-starburst spectral features are visible for ∼250 Myr. The flattening of the low-mass end of the quiescent galaxy stellar mass function seen at z ∼ 1 can be entirely explained by the addition of rapidly quenched galaxies. Only if a significant fraction of post-starburst galaxies have features that are visible for longer than 250 Myr, or they acquire new gas and return to the star-forming sequence, can there be significant growth of the red sequence from a slower quenching route. The shape of the mass function of these transitory post-starburst galaxies resembles that of quiescent galaxies at z ∼ 2, with a preferred stellar mass of log (M/M�) ∼10.6, but evolves steadily to resemble that of star-forming galaxies at z /~ 2 they are exclusively massive galaxies that have formed the bulk of their stars during a rapid assembly period, followed by complete quenching of further star formation; (2) at z </~1 they are caused by the rapid quenching of gas-rich star-forming galaxies, independent of stellar mass, possibly due to environment and/or gas-rich major mergers

    Performance Evaluation of FPGA-Based Biological Applications Olaf

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    On the forefront of recent HPC innovations are Field Programmable Gate Arrays (FPGA), which promise to accelerate calculations by one or more orders of magnitude. The performance of two Cray XD1 systems with Virtex-II Pro 50 and Virtex-4 LX160 FPGAs, were evaluated using a computational biological human genome comparisons program. This paper describes scalable, parallel, FPGA-accelerated results for the FASTA application ssearch34, using the Smith-Waterman algorithm for DNA, RNA and protein sequencing contained in the OpenFPGA benchmark suite. Results indicate typical Cray XD1 FPGA speedups of 50x (Virtex-II Pro 50) and 100x (Virtex-4 LX160) compared to a 2.2 GHz Opteron. Similar speedups are expected for the DRC RPU110-L200 modules (Virtex-4 LX200), which fit in an Opteron socket, and selected by Cray for its XT Supercomputers. The FPGA programming challenges, human genome benchmarking, and data verification of results, are discussed

    Estrangement, Immersion, and the Future:Designing the Speculative Environments of the Virtual Reality “Museum of the Future”

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    This article examines the creation of three speculative environments within the Museum of the Future (MOTF), a virtual-reality environment (VRE) designed by Dstl to promote awareness of future defence and security technologies. In contrast to other areas of the MOTF, these speculative settings are experimental, and are intended to highlight the uncertainty of the future, using techniques of cognitive estrangement and other appropriate narrative and world-building techniques to encourage audiences to query their anticipatory assumptions and cognitive biases. The aim of this project is therefore to promote cognitive flexibility, enhance futures literacy (FL), and ameliorate against the effects of knowledge shields. After a brief overview of the three speculative environments, the article explores the contextual needs they were designed to address, and demonstrates how, through team composition and core design principles, as well as through the application of narrative techniques, the worlds described can offer audiences novel ways of considering possible futures

    Whole-blood methylation signatures are associated with and accurately classify multiple sclerosis disease severity

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    Background: The variation in multiple sclerosis (MS) disease severity is incompletely explained by genetics, suggesting genetic and environmental interactions are involved. Moreover, the lack of prognostic biomarkers makes it difficult for clinicians to optimise care. DNA methylation is one epigenetic mechanism by which gene–environment interactions can be assessed. Here, we aimed to identify DNA methylation patterns associated with mild and severe relapse-onset MS (RMS) and to test the utility of methylation as a predictive biomarker. Methods: We conducted an epigenome-wide association study between 235 females with mild (n = 119) or severe (n = 116) with RMS. Methylation was measured with the Illumina methylationEPIC array and analysed using logistic regression. To generate hypotheses about the functional consequence of differential methylation, we conducted gene set enrichment analysis using ToppGene. We compared the accuracy of three machine learning models in classifying disease severity: (1) clinical data available at baseline (age at onset and first symptoms) built using elastic net (EN) regression, (2) methylation data using EN regression and (3) a weighted methylation risk score of differentially methylated positions (DMPs) from the main analysis using logistic regression. We used a conservative 70:30 test:train split for classification modelling. A false discovery rate threshold of 0.05 was used to assess statistical significance. Results: Females with mild or severe RMS had 1472 DMPs in whole blood (839 hypermethylated, 633 hypomethylated in the severe group). Differential methylation was enriched in genes related to neuronal cellular compartments and processes, and B-cell receptor signalling. Whole-blood methylation levels at 1708 correlated CpG sites classified disease severity more accurately (machine learning model 2, AUC = 0.91) than clinical data (model 1, AUC = 0.74) or the wMRS (model 3, AUC = 0.77). Of the 1708 selected CpGs, 100 overlapped with DMPs from the main analysis at the gene level. These overlapping genes were enriched in neuron projection and dendrite extension, lending support to our finding that neuronal processes, rather than immune processes, are implicated in disease severity. Conclusion: RMS disease severity is associated with whole-blood methylation at genes related to neuronal structure and function. Moreover, correlated whole-blood methylation patterns can assign disease severity in females with RMS more accurately than clinical data available at diagnosis.</p

    Parity is associated with long-term differences in DNA methylation at genes related to neural plasticity in multiple sclerosis

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    Background: Pregnancy in women with multiple sclerosis (wwMS) is associated with a reduction of long-term disability progression. The mechanism that drives this effect is unknown, but converging evidence suggests a role for epigenetic mechanisms altering immune and/or central nervous system function. In this study, we aimed to identify whole blood and immune cell-specific DNA methylation patterns associated with parity in relapse-onset MS. Results: We investigated the association between whole blood and immune cell-type-specific genome-wide methylation patterns and parity in 192 women with relapse-onset MS, matched for age and disease severity. The median time from last pregnancy to blood collection was 16.7 years (range = 1.5–44.4 years). We identified 2965 differentially methylated positions in whole blood, 68.5% of which were hypermethylated in parous women; together with two differentially methylated regions on Chromosomes 17 and 19 which mapped to TMC8 and ZNF577, respectively. Our findings validated 22 DMPs and 366 differentially methylated genes from existing literature on epigenetic changes associated with parity in wwMS. Differentially methylated genes in whole blood were enriched in neuronal structure and growth-related pathways. Immune cell-type-specific analysis using cell-type proportion estimates from statistical deconvolution of whole blood revealed further differential methylation in T cells specifically (four in CD4+ and eight in CD8+ T cells). We further identified reduced methylation age acceleration in parous women, demonstrating slower biological aging compared to nulligravida women. Conclusion: Differential methylation at genes related to neural plasticity offers a potential molecular mechanism driving the long-term effect of pregnancy on MS outcomes. Our results point to a potential ‘CNS signature’ of methylation in peripheral immune cells, as previously described in relation to MS progression, induced by parity. As the first epigenome-wide association study of parity in wwMS reported, validation studies are needed to confirm our findings.</p

    The 100,000 Genomes Project Protocol

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    <div>This document sets out the protocol for the development, delivery, and operation of the 100,000 Genomes Project. It also details the patient and clinical benefits, the scientific and transformational objectives, the implementation strategy, as well as the ethical and governance frameworks required for the Project.</div
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