A new connection between the opening angle and the large-scale morphology of extragalactic radio sources

In the case of an initially conical jet, we study the relation between jet collimation by the external pressure and large-scale morphology. We first consider the important length-scales in the problem, and then carry out axisymmetric hydrodynamic simulations that include, for certain parameters, all these length-scales. We find three important scales related to the collimation region: (i) where the sideways ram-pressure equals the external pressure, (ii) where the jet density equals the ambient density, and (iii) where the forward ram-pressure falls below the ambient pressure. These scales are set by the external Mach-number and opening angle of the jet. We demonstrate that the relative magnitudes of these scales determine the collimation, Mach-number, density and morphology of the large scale jet. Based on analysis of the shock structure, we reproduce successfully the morphology of Fanaroff-Riley (FR) class I and II radio sources. Within the framework of the model, an FR I radio source must have a large intrinsic opening angle. Entrainment of ambient gas might also be important. We also show that all FR I sources with radio lobes or similar features must have had an earlier FR II phase.Comment: 14 pages, 10 figures, accepted by MNRAS, same as previous versio

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

A Framework for Determining Population-Level Vulnerability to Climate: Evidence for Growth Hysteresis in Chamaecyparis thyoides Along Its Contiguous Latitudinal Distribution

The impact of ecological and climatological factors on individual organisms over time and space is inherently complex and creates substantial uncertainty about how climate change will influence the global biosphere. To understand some of this complexity, we investigated the factors influencing individual growth of Chamaecyparis thyoides over 61 years within 18 populations across the ca 1500 km and 11 degrees of latitude. We then applied a vulnerability framework to understand how the variability of tree growth response to climate varies between populations and regions across our network. Surprisingly, we found the growth of trees in the central portion of our network responded more synchronously to warming and drought than trees in the southern end of our network, suggesting greater vulnerability in the central populations with continued warming. Our analyses and framework approach revealed substantial complexity in growth responses to climate within and between populations. We found potential resiliency within all populations, but higher inter-population than intra-population variability in response to climate. We found that latitude was an important proxy for the growth response to temperatures during the non-growing season and spring, but that ecosystem structure can modify the growth response and vulnerability to drought during the summer. The range of growth responses to warming is greater in the southern populations than in more northernly populations. This asymmetrical distribution of growth response across our study network provides evidence for a kind of ecological hysteresis, more southerly populations could be more resilient with warming. Despite the fact that this species primarily lives in wetlands, we found drought stress to be an important constraint on growth. Our study and analyses help to explain the disparities between forecasts of how climatic change might impact tree species and ecosystems over space.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Co-designed Innovation and System for Resilient Exascale Computing in Europe: From Applications to Silicon (EuroEXA)

EuroEXA targets to provide the template for an upcoming exascale system by co-designing and implementing a petascale-level prototype with ground-breaking characteristics. To accomplish this, the project takes a holistic approach innovating both across the technology and the application/system software pillars. EuroEXA proposes a balanced architecture for compute and data-intensive applications, that builds on top of cost-efficient, modular-integration enabled by novel inter-die links, utilises a novel processing unit and embraces FPGA acceleration for computational, networking and storage operations. EuroEXA hardware designers work together with system software experts optimising the entire stack from language runtimes to low-level kernel drivers, and application developers that bring in a rich mix of key HPC applications from across climate/weather, physical/energy and life-science/bioinformatics domains to enable efficient system co-design and maximise the impact of the project

Genomic investigations of unexplained acute hepatitis in children

Funding: UKHSA funded the metagenomics and HAdV sequencing. The work was part funded by the NIHR Blood and Transplant Research Unit in Genomics to Enhance Microbiology Screening (GEMS), the National Institute for Health and Care Research (CO-CIN-01) or jointly by NIHR and UK Research and Innovation (CV220-169, MC_PC_19059). S. Morfopoulou is funded by a W.T. Henry Wellcome fellowship (206478/Z/17/Z). S.B. and O.E.T.M. are funded by the NIHR Blood and Transplant Research Unit (GEMS). M.M.M. and M.L. are supported in part by the NIHR Biomedical Research Centre of Imperial College NHS Trust. J.B. receives NIHR Senior Investigator Funding. M.N. and J.B. are supported by the Wellcome Trust (207511/Z/17/Z and 203268/Z/16/Z). M.N., J.B. and G.P. are supported by the NIHR University College London Hospitals Biomedical Research Centre. P. Simmonds is supported by the NIHR (NIHR203338). T.S.J. is grateful for funding from the Brain Tumour Charity, Children with Cancer UK, GOSH Children’s Charity, Olivia Hodson Cancer Fund, Cancer Research UK and the NIHR. DIAMONDS is funded by the European Union (Horizon 2020; grant 848196). PERFORM was funded by the European Union (Horizon 2020; grant 668303).Since its first identification in Scotland, over 1000 cases of unexplained pediatric hepatitis in children have been reported worldwide, including 278 cases in the UK 1. Here we report investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator subjects, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in liver, blood, plasma or stool from 27/28 cases. We found low levels of Adenovirus (HAdV) and Human Herpesvirus 6B (HHV-6B), in 23/31 and 16/23 respectively of the cases tested. In contrast, AAV2 was infrequently detected at low titre in blood or liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T-cells and B-lineage cells. Proteomic comparison of liver tissue from cases and healthy controls, identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and in severe cases HHV-6B, may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children.Publisher PDFPeer reviewe