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We present the results of Monte Carlo mass-loss predictions for massive stars covering a wide range of stellar parameters. We critically test our predictions against a range of observed mass-loss rates -- in light of the recent discussions on wind clumping. We also present a model to compute the clumping-induced polarimetric variability of hot stars and we compare this with observations of Luminous Blue Variables, for which polarimetric variability is larger than for O and Wolf-Rayet stars. Luminous Blue Variables comprise an ideal testbed for studies of wind clumping and wind geometry, as well as for wind strength calculations, and we propose they may be direct supernova progenitors.
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Massive stars and supernovae (SNe) have a huge impact on their environment. Despite their importance, a comprehensive knowledge of which massive stars produce which SNe is hitherto lacking. We use a Monte Carlo method to predict the mass-loss rates of massive stars in the Hertzsprung-Russell Diagram (HRD) covering all phases from the OB main sequence, the unstable Luminous Blue Variable (LBV) stage, to the final Wolf-Rayet (WR) phase. Although WR produce their own metals, a strong dependence of the mass-loss rate on the initial iron abundance is found at sub-solar metallicities (1/10 -- 1/100 solar). This may present a viable mechanism to prevent the loss of angular momentum by stellar winds, which could inhibit GRBs occurring at solar metallicities -- providing a significant boost to the collapsar model. Furthermore, we discuss recently reported quasi-sinusoidal modulations in the radio lightcurves of SNe 2001ig and 2003bg. We show that both the sinusoidal behaviour and the recurrence timescale of these modulations are consistent with the predicted mass-loss behaviour of LBVs. We discuss potential ramifications for the ``Conti scenario for massive star evolution.
The deluge of digital information in our daily life -- from user-generated content, such as microblogs and scientific papers, to online business, such as viral marketing and advertising -- offers unprecedented opportunities to explore and exploit the trajectories and structures of the evolution of information cascades. Abundant research efforts, both academic and industrial, have aimed to reach a better understanding of the mechanisms driving the spread of information and quantifying the outcome of information diffusion. This article presents a comprehensive review and categorization of information popularity prediction methods, from feature engineering and stochastic processes, through graph representation, to deep learning-based approaches. Specifically, we first formally define different types of information cascades and summarize the perspectives of existing studies. We then present a taxonomy that categorizes existing works into the aforementioned three main groups as well as the main subclasses in each group, and we systematically review cutting-edge research work. Finally, we summarize the pros and cons of existing research efforts and outline the open challenges and opportunities in this field.
The closest examples of high-mass star birth occurs in deeply embedded environments at kiloparsec distances. Although much progress has been made, an observationally validated picture of the dominant processes which allows the central hydrostatic object to grow in mass has yet to be established. The observational technique of optical interferometry has demonstrated its potential in the field of high-mass star formation by delivering a milli-arcsecond infrared view on the complex accretion environment. We provide an overview of the scientific results obtained with multi-aperture telescope arrays and briefly discuss future instruments and their anticipated impact on our understanding of massive young stellar objects.
Predictions for the Higgs masses are a distinctive feature of supersymmetric extensions of the Standard Model, where they play a crucial role in constraining the parameter space. The discovery of a Higgs boson and the remarkably precise measurement of its mass at the LHC have spurred new efforts aimed at improving the accuracy of the theoretical predictions for the Higgs masses in supersymmetric models. The Precision SUSY Higgs Mass Calculation Initiative (KUTS) was launched in 2014 to provide a forum for discussions between the different groups involved in these efforts. This report aims to present a comprehensive overview of the current status of Higgs-mass calculations in supersymmetric models, to document the many advances that were achieved in recent years and were discussed during the KUTS meetings, and to outline the prospects for future improvements in these calculations.
A large number of massive stars are known to rotate, resulting in significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass loss is temperature dependent, so rapid rotation produces variation in mass loss and angular momentum loss rates across the surface of the star, which is expected to affect the evolution of rapidly rotating massive stars. In this work, we investigate the two dimensional effects of rotation on radiatively driven mass loss and the associated loss of angular momentum in ZAMS models with solar metallicity. Using 2D stellar models, which give the variation in surface parameters as a function of co-latitude, we implement two different mass loss prescriptions describing radiatively driven mass loss. We find a significant variation in mass loss rates and angular momentum loss as a function of co-latitude. We find that the mass loss rate decreases as the rotation rate increases for models at constant initial mass, and derive scaling relations based on these models. When comparing 2D to 1D mass loss rates, we find that although the total angle integrated mass loss does not differ significantly, the 2D models predict less mass loss from the equator and more mass loss from the pole than the 1D predictions using von Zeipels law. As a result, rotating models lose less angular momentum in 2D than in 1D, which will change the subsequent evolution of the star. The evolution of these models will be investigated in future work.
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