45 research outputs found
Implications of H.E.S.S. observations of pulsar wind nebulae
In this review paper on pulsar wind nebulae (PWN) we discuss the properties
of such nebulae within the context of containment against cross-field diffusion
(versus normal advection), the effect of reverse shocks on the evolution of
offset ``Vela-like'' PWN, constraints on maximum particle energetics, magnetic
field strength estimates based on spectral and spatial properties, and the
implication of such field estimates on the composition of the wind. A
significant part of the discussion is based on the High Energy Stereoscopic
System ({\it H.E.S.S.} or {\it HESS}) detection of the two evolved pulsar wind
nebulae Vela X (cocoon) and HESS J1825-137. In the case of Vela X (cocoon) we
also review evidence of a hadronic versus a leptonic interpretation, showing
that a leptonic interpretation is favored for the {\it HESS} signal. The
constraints discussed in this review paper sets a general framework for the
interpretation of a number of offset, filled-center nebulae seen by {\it HESS}.
These sources are found along the galactic plane with galactic latitudes
, where significant amounts of molecular gas is found. In these
regions, we find that the interstellar medium is inhomogeneous, which has an
effect on the morphology of supernova shock expansion. One consequence of this
effect is the formation of offset pulsar wind nebulae as observed.Comment: to appear in Springer Lecture Notes on Neutron Stars and Pulsars: 40
years after their discovery, eds. W. Becke
The 2014 ALMA Long Baseline Campaign: First Results from High Angular Resolution Observations toward the HL Tau Region
Interstellar matter and star formatio
The 2014 ALMA Long Baseline Campaign: An Overview
Instrumentatio
Universal DNA methylation age across mammalian tissues
DATA AVAILABILITY STATEMENT : The individual-level data from the Mammalian Methylation Consortium can be accessed from several online locations. All data from the Mammalian Methylation Consortium are posted on Gene Expression Omnibus (complete dataset, GSE223748). Subsets of the datasets can also be downloaded from accession numbers GSE174758, GSE184211, GSE184213, GSE184215, GSE184216, GSE184218, GSE184220, GSE184221, GSE184224, GSE190660, GSE190661, GSE190662, GSE190663, GSE190664, GSE174544, GSE190665, GSE174767, GSE184222, GSE184223, GSE174777, GSE174778, GSE173330, GSE164127, GSE147002, GSE147003, GSE147004, GSE223943 and GSE223944. Additional details can be found in Supplementary Note 2. The mammalian data can also be downloaded from the Clock Foundation webpage: https://clockfoundation.org/MammalianMethylationConsortium. The mammalian methylation array is available through the non-profit Epigenetic Clock Development Foundation (https://clockfoundation.org/). The manifest file of the mammalian array and genome annotations of CpG sites can be found on Zenodo (10.5281/zenodo.7574747). All other data supporting the findings of this study are available from the corresponding author upon reasonable request.
The chip manifest files, genome annotations of CpG sites and the software code for universal pan-mammalian clocks can be found on GitHub95 at https://github.com/shorvath/MammalianMethylationConsortium/tree/v2.0.0. The individual R code for the universal pan-mammalian clocks, EWAS analysis and functional enrichment studies can be also found in the Supplementary Code.SUPPLEMENTARY MATERIAL 1 : Supplementary Tables 1–3 and Notes 1–6.SUPPLEMENTARY MATERIAL 2 : Reporting SummarySUPPLEMENTARY MATERIAL 3 : Supplementary Data 1–14.SUPPLEMENTARY MATERIAL 4 : Supplementary Code.Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.https://www.nature.com/nataginghj2024Zoology and EntomologySDG-15:Life on lan
Microstructural Evolution by Continuous Recrystallization in a Superplastic Al-Mg Alloy
The boundary misorientations in an Al-1OMg-O.1Zr (wt%) alloy, thermomechanically processed by rolling at 573 K (300°C), were determined both in annealed and in superplastically deformed conditions. A high initial dislocation density in as-rolled material, which obscured any underlying structure, rapidly transformed into a well-defined structure containing boundaries. After annealing for 600 s at 573K, boundaries with misorientations of 1–5° were observed. With further annealing (3000 s), misorientations did not change appreciably and were measured to be 2–7°. Such time represents that necessary to equilibrate at 573K prior to tension testing at that temperature. The material exhibits superplasticity from the onset of deformation and after 100% strain, misorientations were observed to increase to 20–30°. It was concluded that boundaries of such initial misorientations can support superplastic deformation mechanisms including grain boundary sliding.U.S. Naval Air Systems CommandUniversity of Illinoi
An EBSP investigation of alternate microstructures for superplasticity in aluminum-magnesium alloys
The article of record as published may be found at http://dx.doi.org/101016/S1359-6462(96)00403-4This study proposes to provide insight into alternative grain boundary structures in two aluminum-magnesium alloys processed to achieve superplastic behavior. A commercially processes superplastic 5083 aluminum alloy, SKY5083, and a laboratory processed, non-commercial superplastic Al-10Mg-0.1Zr alloy have been selected for examination. Although alloy content, processing routes, and deformation conditions vary for each material, a comparison of results may provide evidence that alternate grain structures and boundary misorientation distributions may support superplasticity in the GBS regime, depending on the TMP processing and alloy system chosen
GRAIN REFINEMENT AND SUPERPLASTICITY IN A LITHIUM-CONTAINING Al-Mg ALLOY BY THERMOMECHANICAL PROCESSING
The refined microstructures and superplastic properties resulting from controlled thermomechanical processing of an Al-8Mg-0.5Li-0.23Zr alloy were evaluated. Rolling between the solvus temperatures for Mg and Li in the alloy allowed for grain refinement by precipitation of β (Al8Mg5) during deformation and subsequent precipitation of δ' (Al3Li) on cooling. Increasing the rolling strain enhance the superplastic ductility of the alloy at 573K in the strain-rate regime of 10-3-10-2 S-1. Elongations in excess of 500 pct. , without cavitation, and a corresponding strain-rate sensitivity coefficient of approximately 0.5, were obtained. TEM investigations of the microstructural characteristics responsible for the mechanical behavior revealed that a more uniformly refined grain structure (3-5µm) evolved by continuous recrystallization (CRX) in material experiencing the larger rolling strain