Comparison of advanced gravitational-wave detectors

We compare two advanced designs for gravitational-wave antennas in terms of their ability to detect two possible gravitational wave sources. Spherical, resonant mass antennas and interferometers incorporating resonant sideband extraction (RSE) were modeled using experimentally measurable parameters. The signal-to-noise ratio of each detector for a binary neutron star system and a rapidly rotating stellar core were calculated. For a range of plausible parameters we found that the advanced LIGO interferometer incorporating RSE gave higher signal-to-noise ratios than a spherical detector resonant at the same frequency for both sources. Spheres were found to be sensitive to these sources at distances beyond our galaxy. Interferometers were sensitive to these sources at far enough distances that several events per year would be expected

Eureka and beyond: mining's impact on African urbanisation

This collection brings separate literatures on mining and urbanisation together at a time when both artisanal and large-scale mining are expanding in many African economies. While much has been written about contestation over land and mineral rights, the impact of mining on settlement, notably its catalytic and fluctuating effects on migration and urban growth, has been largely ignored. African nation-states’ urbanisation trends have shown considerable variation over the past half century. The current surge in ‘new’ mining countries and the slow-down in ‘old’ mining countries are generating some remarkable settlement patterns and welfare outcomes. Presently, the African continent is a laboratory of national mining experiences. This special issue on African mining and urbanisation encompasses a wide cross-section of country case studies: beginning with the historical experiences of mining in Southern Africa (South Africa, Zambia, Zimbabwe), followed by more recent mineralizing trends in comparatively new mineral-producing countries (Tanzania) and an established West African gold producer (Ghana), before turning to the influence of conflict minerals (Angola, the Democratic Republic of Congo and Sierra Leone)

Interleukin-6 Receptor Antagonists in Critically Ill Patients with Covid-19.

BACKGROUND: The efficacy of interleukin-6 receptor antagonists in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear. METHODS: We evaluated tocilizumab and sarilumab in an ongoing international, multifactorial, adaptive platform trial. Adult patients with Covid-19, within 24 hours after starting organ support in the intensive care unit (ICU), were randomly assigned to receive tocilizumab (8 mg per kilogram of body weight), sarilumab (400 mg), or standard care (control). The primary outcome was respiratory and cardiovascular organ support-free days, on an ordinal scale combining in-hospital death (assigned a value of -1) and days free of organ support to day 21. The trial uses a Bayesian statistical model with predefined criteria for superiority, efficacy, equivalence, or futility. An odds ratio greater than 1 represented improved survival, more organ support-free days, or both. RESULTS: Both tocilizumab and sarilumab met the predefined criteria for efficacy. At that time, 353 patients had been assigned to tocilizumab, 48 to sarilumab, and 402 to control. The median number of organ support-free days was 10 (interquartile range, -1 to 16) in the tocilizumab group, 11 (interquartile range, 0 to 16) in the sarilumab group, and 0 (interquartile range, -1 to 15) in the control group. The median adjusted cumulative odds ratios were 1.64 (95% credible interval, 1.25 to 2.14) for tocilizumab and 1.76 (95% credible interval, 1.17 to 2.91) for sarilumab as compared with control, yielding posterior probabilities of superiority to control of more than 99.9% and of 99.5%, respectively. An analysis of 90-day survival showed improved survival in the pooled interleukin-6 receptor antagonist groups, yielding a hazard ratio for the comparison with the control group of 1.61 (95% credible interval, 1.25 to 2.08) and a posterior probability of superiority of more than 99.9%. All secondary analyses supported efficacy of these interleukin-6 receptor antagonists. CONCLUSIONS: In critically ill patients with Covid-19 receiving organ support in ICUs, treatment with the interleukin-6 receptor antagonists tocilizumab and sarilumab improved outcomes, including survival. (REMAP-CAP ClinicalTrials.gov number, NCT02735707.)

The APEX Large CO Heterodyne Orion Legacy Survey (ALCOHOLS): I. Survey overview

Context: The Orion molecular cloud complex harbours the nearest Giant Molecular Clouds (GMCs) and the nearest site of high-mass star formation. Its young star and protostar populations are thoroughly characterized. The region is therefore a prime target for the study of star formation. Aims: Here, we verify the performance of the SuperCAM 64 pixel heterodyne array on the Atacama Pathfinder Experiment (APEX). We give a descriptive overview of a set of wide-field CO(3-2) spectral line cubes obtained towards the Orion GMC complex, aimed at characterizing the dynamics and structure of the extended molecular gas in diverse regions of the clouds, ranging from very active sites of clustered star formation in Orion B to comparatively quiet regions in southern Orion A. In a future publication, we will characterize the full population of protostellar outflows and their feedback over an entire GMC. Methods: We present a 2.7 square degree (130 pc2) mapping survey in the 12CO(3-2) transition, obtained using SuperCAM on APEX at an angular resolution of 1900 (7600 AU or 0.037 pc at a distance of 400 pc), covering the main sites of star formation in the Orion B cloud (L 1622, NGC 2071, NGC 2068, Ori B9, NGC 2024, and NGC 2023), and a large patch in the southern part of the L 1641 cloud in Orion A. Results: We describe CO integrated line emission and line moment maps and position-velocity diagrams for all survey fields and discuss a few subregions in some detail. Evidence for expanding bubbles is seen with lines splitting into double components, often in areas of optical nebulosities, most prominently in the NGC 2024 H ii region, where we argue that the bulk of the molecular gas is in the foreground of the H ii region. High CO(3-2)/CO(1-0) line ratios reveal warm CO along the western edge of the Orion B cloud in the NGC 2023/NGC 2024 region facing the IC 434 H ii region. We see multiple, well separated radial velocity cloud components towards several fields and propose that L 1641-S consists of a sequence of clouds at increasingly larger distances. We find a small, seemingly spherical cloud, which we term ’Cow Nebula’ globule, north of NGC 2071. We confirm that we can trace high velocity line wings out to the ’extremely high velocity’ regime in protostellar molecular outflows for the NGC 2071-IR outflow and the NGC 2024 CO jet, and identify the protostellar dust core FIR4 (rather than FIR5) as the true driving source of the NGC 2024 monopolar outflow

Photometric and spectroscopic evolution of the interacting transient at 2016jbu(Gaia16cfr)

We present the results from a high-cadence, multiwavelength observation campaign of AT 2016jbu (aka Gaia16cfr), an interacting transient. This data set complements the current literature by adding higher cadence as well as extended coverage of the light-curve evolution and late-time spectroscopic evolution. Photometric coverage reveals that AT 2016jbu underwent significant photometric variability followed by two luminous events, the latter of which reached an absolute magnitude of MV ∼-18.5 mag. This is similar to the transient SN 2009ip whose nature is still debated. Spectra are dominated by narrow emission lines and show a blue continuum during the peak of the second event. AT 2016jbu shows signatures of a complex, non-homogeneous circumstellar material (CSM). We see slowly evolving asymmetric hydrogen line profiles, with velocities of 500 km s-1 seen in narrow emission features from a slow-moving CSM, and up to 10 000 km s-1 seen in broad absorption from some high-velocity material. Late-time spectra (∼+1 yr) show a lack of forbidden emission lines expected from a core-collapse supernova and are dominated by strong emission from H, He i, and Ca ii. Strong asymmetric emission features, a bumpy light curve, and continually evolving spectra suggest an inhibit nebular phase. We compare the evolution of H α among SN 2009ip-like transients and find possible evidence for orientation angle effects. The light-curve evolution of AT 2016jbu suggests similar, but not identical, circumstellar environments to other SN 2009ip-like transients

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Doping of sub-50nm SOI layers

Doping of thin body Si becomes very essential topic due to increasing interest of forming source/drain regions in fully depleted planar silicon-on-isolator (SOI) devices or vertical Fin field-effect-transistors (FinFETs). To diminish the role of the short-channel-effect (SCE) control, the Si layers thicknesses target the 10 nm range. In this paper many aspects of thin Si body doping are discussed: dopant retention, implantation-related amorphization, thin body recrystn., sheet resistance (Rs) and carrier mobility in cryst. or amorphized material, impact of the annealing ambient on Rs for various SOI thicknesses. The complexity of 3D geometry for vertical Fin and the vicinity of the extended surface have an impact on doping strategies that are significantly different than for planar bulk devices

Doping of sub-50nm SOI layers

Doping of thin body Si becomes very essential topic due to increasing interest of forming source/drain regions in fully depleted planar silicon-on-isolator (SOI) devices or vertical Fin field-effect-transistors (FinFETs). To diminish the role of the short-channel-effect (SCE) control, the Si layers thicknesses target the 10 nm range. In this paper many aspects of thin Si body doping are discussed: dopant retention, implantation-related amorphization, thin body recrystn., sheet resistance (Rs) and carrier mobility in cryst. or amorphized material, impact of the annealing ambient on Rs for various SOI thicknesses. The complexity of 3D geometry for vertical Fin and the vicinity of the extended surface have an impact on doping strategies that are significantly different than for planar bulk devices

Doping fin field-effect transistor sidewalls : impurity dose retention in silicon due to high angle incident ion implants and the impact on device performance

The three dimensional (3D) nature of a fin field-effect transistor (FinFET) structure creates new challenges for an impurity doped region formation. For the triple gate FinFET, both top and side surfaces require high levels of dopant incorporation to minimize access resistance. In this work, we investigate the use of conventional ion implantation for the introduction of impurities in this 3D silicon structure. Specifically, we evaluate sidewall impurity dose retention at various angles of incidence. The retention of dose is detd. by (i) trigonometry of the implant angle in the 3D fin system, (ii) backscattering, and (iii) material properties of the target surface. Dose retention is most sensitive to the implant angle. For a fixed implant projected range, lighter ions are more likely to be ejected from the target. Thus, heavier ions are better for dose retention. The influence of sidewall dose retention on the elec. performance of fully depleted FinFETs was investigated by means of 3D device simulation. Drive current and short channel effect control are more sensitive to dose retention on sidewalls than to dopant conformality