Tootfinder

Current and former employees of OpenAI have sold nearly $3B worth of shares in tender offers since 2021, with $1.5B going to SoftBank alone (Natasha Mascarenhas/The Information)
https://www.theinformation.com/articles/openai-employees-cashed-3-bil…

OpenAI Employees Have Cashed Out $3 Billion in Shares
My colleague Sri Muppidi broke the news Wednesday of OpenAI’s latest fundraising talks as it seeks to raise an unprecedented $40 billion. One previously unreported detail is that SoftBank bought about $240 million in shares from a small group of current and former employees this spring.That deal ...

Current Disasters FEMA is working on
https://www.fema.gov/disaster/current
Fate of US disaster relief agency FEMA still being discussed
https://www.reuters.com/world/us/trump-administration-scraps-plan-abolish-fema-washington-post-reports-2025-07-11/

Suns in triangle-free graphs of large chromatic number
Sepehr Hajebi, Sophie Spirkl
https://arxiv.org/abs/2506.10227 https://arxiv.or…

Suns in triangle-free graphs of large chromatic number
For an integer $t\geq 4$, a $t$-sun is a graph obtained from a $t$-vertex cycle $C$ by adding a degree-one neighbor for each vertex of $C$. Trotignon asked whether every triangle-free graph of sufficiently large chromatic number has an induced subgraph that is a $t$-sun for some $t\geq 4$. This remains open, but we show that every triangle-free graph of chromatic number at least $44$ has an induced subgraph that is either a $t$-sun for some $t\geq 5$, or a $4$-sun with a single degree-one verte…

Field-free perpendicular magnetization switching by altermagnet with collinear spin current
M. Q. Dong, Zhi-Xin Guo, Xin-Gao Gong
https://arxiv.org/abs/2506.10336

Field-free perpendicular magnetization switching by altermagnet with collinear spin current
The generation of collinear spin current (CSC), where both the propagation direction and spin-polarized direction aligned perpendicularly to the applied charge current, is crucial for efficiently manipulating systems with perpendicular magnetic anisotropy used in high-density magnetic recording. However, the efficient generation of CSC remains a challenge. In this work, based on the symmetry analysis, we propose that CSC can be effectively generated using altermagnets when the charge current is…

Flash Floods and Climate Policy (Elizabeth Kolbert/New Yorker)
https://www.newyorker.com/magazine/2025/07/21/flash-floods-and-climate-policy?currentPage=all
http://www.memeorandum.com/250712/p12#a250712p12

Current status (Air Quality)

Coherent states of finite-level systems
A. I. Breev, D. M. Gitman
https://arxiv.org/abs/2506.10668 https://arxiv.org/pdf/2506.10668…

Coherent states of finite-level systems
A method for constructing coherent states (CS) of finite-level systems with a given angular momentum is proposed. To this end we generalize the known spin equation (SE) to an infinite-dimensional Fock space. The equation describes a special quadratic system in the latter space. Its projections on $d$-dimensional subspaces, represent analogs of SE for $d$-dimensional systems in an external electromagnetic field which describe $d$-dimensional systems with a given angular moment. Using a modificat…

"Ocean currents can generate electricity, and our study shows Africa's seas have some of the strongest"
#Africa #Oceans #Energy

Ocean currents can generate electricity, and our study shows Africa's seas have some of the strongest
The world's oceans cover more than 70% of Earth's surface. They're filled with currents, some much stronger than the fastest flowing large rivers. These currents can be harnessed as clean, marine renewable energy. Marine energy is much more predictable and reliable than many other forms of renewable energy because unlike the sun and wind, which regularly do not produce electricity, ocean currents never stop moving around the planet. New research has found that the eastern and south-eastern coas…

Modelling of Counter-Current Gas-Liquid Annular Flow in a Vertical Annulus
Mahshid Firouzi
https://arxiv.org/abs/2506.10270 https://a…

Modelling of Counter-Current Gas-Liquid Annular Flow in a Vertical Annulus
Annular two-phase flow involving upward-moving gas and downward-flowing liquid within a vertical annular geometry is a common configuration in various engineering systems. In such systems, accurately predicting the pressure gradient is essential for understanding flow stability, equipment performance, and system design under counter-current conditions. This paper presents a general mechanistic model to predict the pressure gradient in counter-current annular flow within a vertical annular space…

Nonlinear Dynamics of Wind-Drift Currents at Mid-Latitudes
Christian Puntini
https://arxiv.org/abs/2506.10454 https://arxiv.org/pdf/2…

Nonlinear Dynamics of Wind-Drift Currents at Mid-Latitudes
Starting from the Navier-Stokes equation in the $f$-plane approximation, we provide an exact and explicit solution of the governing equations at leading order for fluid flows in the upper layer of the ocean, driven by a wind stress. Such a solution highlights the presence of a mean Ekman current superimposed to trochoidal oscillations and a background geostrophic current.