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Nonlinear model reduction to spectral submanifolds is now available even under general (e.g., chaotic) forcing. Asymptotic expansions for generalized steady states of aperiodically forced mechanical systems also follow from these results.

49,120 просмотров • 2 лет назад •via X (Twitter)

Комментарии: 3

Фото профиля BuyHoldAndSTFU
BuyHoldAndSTFU2 лет назад

@stevenstrogatz Beautiful.

Фото профиля George Haller
George Haller2 лет назад

@stevenstrogatz Thanks!

Фото профиля Algebrium
Algebrium2 лет назад

Let x(t) ∈ ℝ^n.The nonlinear diff equ: dx(t)/dt = f(x(t)) f: ℝ^n → ℝ^n. Let z(t) ∈ ℝ^m(m < n). The model dynamics are dz(t)/dt = g(z(t)) g: ℝ^m → ℝ^m. The goal : find g(z(t)) s.t the trajectories of z(t) closely approximate dynamics of the original system x(t).

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What seemed like an intractable problem is now possible: To design proteins with a specified nonlinear mechanical response, capturing complex folding and unfolding mechanisms in singe and few-shot computations. We present ForceGen, an end-to-end algorithm for de novo protein generation based on nonlinear mechanical unfolding responses. Rooted in the physics of protein mechanics, this generative strategy provides a powerful way to design new proteins rapidly, including exquisite and rapid predictions about their dynamical behavior. Proteins, like any other mechanical object, respond to forces in peculiar ways. Think of the different response you'd get from pulling on a steel cable versus pulling on a rubber band, or the difference between honey and glass. Now, we can design proteins with a set of desirable mechanical characteristics, with applications from health to sustainable plastics. The key to solving this problem was to integrate a protein language model with denoising diffusion methods, and using accurate atomistic-level physical simulation data to endow the model a first-principles understanding. ForceGen can solve both forward and inverse tasks: In the forward task, we can predict how stable a protein is, how it will unfold and what the forces involved are, all given just the sequence of amino acids. In the inverse task, we can design new proteins that meet complex nonlinear mechanical signature targets. Read the paper, led by LAMM@MIT postdoc Bo Ni, published in Science Advances: Why do we care about the mechanics of proteins? The mechanics of proteins are critical elements of many living systems - as evidenced in many studies of mechanobiology. Through evolution, nature has presented a set of remarkable protein materials with unique mechanical functions like elastins, silks, keratins or collagens that play crucial roles in biology. However, going beyond natural designs to discover proteins that meet specified mechanical properties remains challenging. So far, the only way to do this was to use existing evolutionary concepts or to manually alter proteins. With our new generative model we can directly design proteins to meet complex nonlinear mechanical property-design objectives. ForceGen leverages deep knowledge on protein sequences from a pretrained protein language model and maps mechanical unfolding responses to create proteins. Via full-atom molecular simulations for direct validation from physical and chemical principles, we demonstrate that the designed proteins are de novo, and fulfill the targeted mechanical properties, including unfolding energy and mechanical strength, and a detailed unfolding force-separation curves. ForceGen offers rapid pathways to explore the enormous mechanobiological protein sequence space unconstrained by biological synthesis, to enable the discovery of new protein materials with superior mechanical properties. B. Ni, D.L. Kaplan, M.J. Buehler, ForceGen: End-to-end de novo protein generation based on nonlinear mechanical unfolding responses using a language diffusion model. Sci. Adv. 10, eadl4000 (2024). DOI: 10.1126/sciadv.adl4000 Codes and model weights available Hugging Face: David Kaplan

Markus J. Buehler

47,269 просмотров • 2 лет назад

In October, before the 2020 election, Dominion Voting Systems received a $400 MILLION dollar payment from Staple Street Capital, which has ties to China and the CCP. Smartmatic, SGO, and Dominion all allegedly share the same physical address in a small building in Barbados, as a registered headquarters. These companies also share licensing agreements which is also a part of their core software and coding. This connection alone poses a massive national security risk as Smartmatic itself was engineered specifically to alter and manipulate the outcome of elections through backdoors built into the systems, where NO hacking is even required to change election results, it is a feature which was created at the direction of Hugo Chavez to alter election outcomes during Smartmatic's development. The operator's manual itself exposes these backdoor, built-in, features that these systems have that give administrators and operators of these systems full control to alter multiple data points, both on-site and remotely. Testimonies of election workers calling Dominion when problems occurred with Dominion remotely fixing the problems, even after stating under oath that there was no internet connection. Stacy Abrams' website listed numerous vulnerabilities in these systems, Texas rejected using Dominion because they lacked basic security, but swing states and others were allowed to use their systems? These systems seem to have been permitted to use because of their remote and other backdoor capabilities. There were no errors, just sophisticated, intentional, fraud.

The SCIF

24,768 просмотров • 6 месяцев назад

These days, a Ukrainian delegation, including the First Deputy Prime Minister, the Minister of Defense, representatives of the General Staff, and the Head of the Office of the President, is working in Washington. There have been meetings at various levels, and one of our top priorities is securing long-range capabilities for our Defense Forces. This is crucial to preventing the terror that our Kharkiv and other cities across Ukraine are forced to endure. Clearing Ukrainian skies of Russian guided bombs is a powerful step toward forcing Russia to seek an end to the war and a just peace. Our representatives have provided all the necessary information and details to our partners. I am calling on the United States, the United Kingdom, France, and Germany – we need the means to fully and effectively protect Ukraine and its people. We need permissions for long-range capabilities, as well as your long-range shells and missiles. Making these vital decisions cannot be delayed – these are the actions that can have the most significant impact on the course of events. We are also discussing air defense with our partners – systems that are especially needed now, before the start of the school year, to provide more safety for Ukrainian children in schools, for our cities, and our energy infrastructure. We have agreements with partners on air defense systems and missiles for these systems. It's crucial to implement everything as quickly as possible. We are working even more actively these days to secure such news – additional air defense systems. I thank everyone around the world who is helping. I thank to all of Ukraine’s friends who do not stay silent about Russian terror, who respond to the attacks, spread the truth about this war, and urge the world to be more decisive and therefore more effective in defending against Russia.

Volodymyr Zelenskyy / Володимир Зеленський

662,616 просмотров • 2 лет назад