Record Maximum Oscillation Frequency in C-face Epitaxial Graphene Transistors

The maximum oscillation frequency (fmax) quantifies the practical upper bound for useful circuit operation. We report here an fmax of 70 GHz in transistors using epitaxial graphene grown on the C-face of SiC. This is a significant improvement over Si-face epitaxial graphene used in the prior high frequency transistor studies, exemplifying the superior electronics potential of C-face epitaxial graphene. Careful transistor design using a high {\kappa} dielectric T-gate and self-aligned contacts, further contributed to the record-breaking fmax

Baryon content in a sample of 91 galaxy clusters selected by the South Pole Telescope at 0.2 <z < 1.25

We estimate total mass (M500), intracluster medium (ICM) mass (MICM), and stellar mass (M) in a Sunyaev–Zel’dovich effect (SZE) selected sample of 91 galaxy clusters with masses M500 2.5 × 1014 M and redshift 0.2 < z < 1.25 from the 2500 deg2 South Pole Telescope SPT-SZ survey. The total masses M500 are estimated from the SZE observable, the ICM masses MICM are obtained from the analysis of Chandra X-ray observations, and the stellar masses M are derived by fitting spectral energy distribution templates to Dark Energy Survey griz optical photometry and WISE or Spitzer near-infrared photometry. We study trends in the stellar mass, the ICM mass, the total baryonic mass, and the cold baryonic fraction with cluster halo mass and redshift. We find significant departures from self-similarity in the mass scaling for all quantities, while the redshift trends are all statistically consistent with zero, indicating that the baryon content of clusters at fixed mass has changed remarkably little over the past ≈9 Gyr. We compare our results to the mean baryon fraction (and the stellar mass fraction) in the field, finding that these values lie above (below) those in cluster virial regions in all but the most massive clusters at low redshift. Using a simple model of the matter assembly of clusters from infalling groups with lower masses and from infalling material from the low-density environment or field surrounding the parent haloes, we show that the measured mass trends without strong redshift trends in the stellar mass scaling relation could be explained by a mass and redshift dependent fractional contribution from field material. Similar analyses of the ICM and baryon mass scaling relations provide evidence for the so-called ‘missing baryons’ outside cluster virial regions

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

Identification of Entry Factors Involved in Hepatitis C Virus Infection Based on Host-Mimicking Short Linear Motifs

<div><p>Host factors that facilitate viral entry into cells can, in principle, be identified from a virus-host protein interaction network, but for most viruses information for such a network is limited. To help fill this void, we developed a bioinformatics approach and applied it to hepatitis C virus (HCV) infection, which is a current concern for global health. Using this approach, we identified short linear sequence motifs, conserved in the envelope proteins of HCV (E1/E2), that potentially can bind human proteins present on the surface of hepatocytes so as to construct an HCV (envelope)-host protein interaction network. Gene Ontology functional and KEGG pathway analyses showed that the identified host proteins are enriched in cell entry and carcinogenesis functionalities. The validity of our results is supported by much published experimental data. Our general approach should be useful when developing antiviral agents, particularly those that target virus-host interactions.</p></div

Definitions and schematic depictions of network roles.

<p>According to NetCarto [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005368#pcbi.1005368.ref018" target="_blank">18</a>], nodes (small red circles) with z-score of within-module degree ≥ 2.5 are defined as module hubs (nodes with many links, i.e. spikes in the schematic view), and those with z-score < 2.5 are non-hubs. Large circles represent modules. See [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005368#pcbi.1005368.ref018" target="_blank">18</a>] for further details.</p

The AVP/SLiM-protein complex map.

<p>Top panel: (left column) a list of AVPs with their AVPdb identification numbers that have an amino acid sequence containing one or more HCV E1/E2 SLiMs (indicated by the triangles and named at the bottom of the panel) that can bind to a subunit of a protein complex belonging to one of the six main complex groups. The relative efficacies of these AVPs in inhibiting HCV entry according to data provided in the AVPdb [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005368#pcbi.1005368.ref056" target="_blank">56</a>] are indicated by the circles column in the panel with the shading score shown to the right of the panel. Middle panel: the network connecting the nine SLiMs to their group A-F complex target(s). Within each group are VIPs of all the complexes: ovals represent VIPs_direct (gray ovals are R6 VIPs_direct), and rectangles represent VIPs_indirect (not all VIPs_indirect are shown). The ovals and rectangles in bold outline are known HCV entry factors. The horizontal bar represents the plasma membrane, the VIPs below the bar and within the shaded area are ‘peripheral membrane proteins’, and those spanning the bar are ‘integral membrane proteins’. APOE is a peripheral membrane protein located at the extracellular side of the cell membrane. A connection between a viral SLiM and a complex group indicates that at least one protein in the group is targeted by HCV E1 and/or E2 via the viral SLiM. The thickness of the connection roughly scales to the number of proteins targeted by the SLiM in the group. The three numbers in the parenthesis are the number of VIPs_direct, total VIPs (i.e., VIPs_direct plus VIPs_indirect), and unique subunits in the complex group. Bottom panel: the KEGG pathways enriched in the complex group (Benjamini-Hochberg adjusted P < 0.001) (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005368#pcbi.1005368.s016" target="_blank">S6 Table</a> for the pathway names). The gray scale at bottom right indicate the significance of the P-values. The functions of the individual KEGG pathways are shown at the left of the panel and the main functionality at the right of the panel.</p