A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni

Observations of binary stars containing an accreting black hole or neutron star often show x-ray emission extending to high energies (>10 kilo­–electron volts), which is ascribed to an accretion disk corona of energetic particles akin to those seen in the solar corona. Despite their ubiquity, the physical conditions in accretion disk coronae remain poorly constrained. Using simultaneous infrared, optical, x-ray, and radio observations of the Galactic black hole system V404 Cygni, showing a rapid synchrotron cooling event in its 2015 outburst, we present a precise 461 ± 12 gauss magnetic field measurement in the corona. This measurement is substantially lower than previous estimates for such systems, providing constraints on physical models of accretion physics in black hole and neutron star binary systems. This article has a correction. Please see: http://science.sciencemag.org/content/360/6386/eaat927

Erratum for the Report “A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni”

In the Report “A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni,” a calculation error led to values of the magnetic field that were about 14 times too high. The mathematical expressions given in the Report were correct, but the code used to calculate the numerical values included an extraneous factor, which led to incorrect results. The magnetic fields calculated from the observations at different wavelengths were all scaled by the same factor, so after this is removed they remain consistent with each other. The corrected value of the magnetic field is lower than previously calculated, making the field in V404 Cygni even more unlike those estimated for other systems. However, the lower magnetic field is no longer consistent with the value predicted from the equipartition model. The text, materials and methods, Table S1, and Figure S3 have been updated to reflect the corrected magnetic field values and to state that the system was not in equipartition. No other results or conclusions of the study were affected. The authors thank J. Malzac (Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse) for alerting them to this error

The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk–outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01–4·94) deaths and 105 million (95·0–116) DALYs for both sexes combined, representing 44·4% (41·3–48·4) of all cancer deaths and 42·0% (39·1–45·6) of all DALYs. There were 2·88 million (2·60–3·18) risk-attributable cancer deaths in males (50·6% [47·8–54·1] of all male cancer deaths) and 1·58 million (1·36–1·84) risk-attributable cancer deaths in females (36·3% [32·5–41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6–28·4) and DALYs by 16·8% (8·8–25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9–42·8] and 33·3% [25·8–42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden

A rationale for the quality index of Al-Si-Mg casting alloys

The quality index introduced on empirical grounds by Drouzy, Jacob and Richard(1) is widely used by the casting industry as a tool for predicting the effect of solidification rate, chemical additions and heat treatment on the ductility and tensile strength of Al-7Si-Mg casting alloys. A drawback of the approach is its lack of physical justification. A simple analytical model is used to derive the quality index charts for Al-7Si-0.4 Mg alloys and to provide a physical meaning to the parameters involved. It is shown that the quality index relates to the fraction of uniform deformation available to the material. The application of the concept to Cu-containing alloys is also discussed

Economical and environmental factors in light alloys automotive applications

The effects of mass reduction through substitution of ferrous components by equivalent Al or Mg alloy components on the vehicle's cost and CO2 emissions are discussed using M.F. Ashby's penalty functions and exchange constants method. The viability of substitutions of At alloys by Mg alloys is also considered. Substitutions of cast components at equal volume and panels and beams at constant stiffness are considered. Substitutions of cast ferrous components are economically the only viable ones in terms of the CAFE (Corporate Average Fuel Economy) liability, although the cost penalty can be fully offset by the gasoline savings over the life of the car for most other forms of light alloy substitutions. When primary alloys are used, the gasoline savings over the lifetime of a lighter car offset the CO2 footprint of Al alloys in all cases. Because of their larger CO2 footprint, the environmental feasibility is somewhat restricted for electrolytic Mg, and more so for Mg produced by the Pidgeon process. Due to their high recyclability, Al casting alloys have a significant environmental advantage over all other light alloy applications. Viable substitutions of existing Al components by Mg components are largely restricted to castings of electrolytic Mg

Dendrite cell size and ductility of Al-Si-Mg casting alloys: Spear and Gardner revisited

Spear and Gardner's classical results † indicate that the tensile ductility of Al-7% Si-0.4% Mg casting alloy increases with decreasing dendrite cell size. However, new experiments show that this relationship is not always followed. Spear and Gardner's results are re-examined in the light of recent observations regarding the fracture mode and the effects of Si particle size and shape on the ductility of this alloy. It is shown that Spear and Gardner's measurements of tensile ductility follow a stepwise dependence on the scale of the dendritic structure, in agreement with more recent results. This behaviour can be related to the Si particle size and morphology which determine the rate of particle cracking with the applied strain for any given dendrite cell size and to changes in the particle distribution brought about by the heat treatment. The latter causes a transition in the fracture mode, from intergranular for the finest cells, when the ductility is highest, to transgranular along the dendrite cell boundaries at intermediate and large cell sizes, when the ductility is moderate or low

Solute and temperature effects on the strain hardening behaviour of Mg-Zn solid solutions

The Kocks-Mecking method of analysis is applied to solid solutions of up to 2.6 at.% Zn to separate the contributions to the alloys' strain hardening rate from dislocations storage, solute in solution, and twinning, for temperatures between -50 degrees C (273 K) and 200 degrees C (473 K). Athermal storage of dislocations seems to account for the largest share of the strain hardening rate for both the pure metal and the solid solutions at or below room temperature. Solute in solution does not increase the strain hardening rate over that of pure Mg, although it delays the onset of dynamic recovery, especially for the higher alloys, presumably due to short range order. Twinning remains a very important deformation mechanism for the pure metal and the dilute alloys up to 200 degrees C

On the strain to the onset of serrated flow in a magnesium alloy

Acoustic emission and transverse strain measurements are used to show that small strain bands appear superimposed onto the homogeneous deformation from the onset of gross plastic deformation. The strain carried by the bands gradually increases until they completely suppress the uniform deformation, at strains between 1.5% and 5%, depending on the strain rate. When this happens, macroscopic serrations are detected in the stress-strain curve. The results are discussed in terms of a current non-diffusional theory for the Portevin-Le Chatelier effect. (c) 2007 Acta Materialia Inc.. Published by Elsevier Ltd. All rights reserved

INTERMETALLICS DISTRIBUTION IN TWO AND THREE DIMENSIONS IN HIGH PRESSURE DIE CAST AZ91 ALLOY

Scanning Electron Microscope (SEM) and DUalBeam FIB (Focussed Ion Beam) were used to characterize the intermetallic microstructure in 2D and 3D, respectively. The intermetallic appears as a closely interconnected network with very fine scale near the surface, while it takes a more open structure in the core regions of the casting. The possible effects of this difference in the scale of the intermetallic structure on the mechanical behaviour of the material are discussed