Plus: Amazon has listed retailers' goods without their permission Last spring, 3,000 British soldiers deployed an invisible automated intelligence network, known as a "digital targeting web," as part of a NATO exercise called Hedgehog in the damp forests of Estonia's eastern territories. The system had been cobbled together over the course of four months--an astonishing pace for weapons development, which is usually measured in years. Its purpose is to connect everything that looks for targets--"sensors," in military lingo--and everything that fires on them ("shooters") to a single, shared wireless electronic brain. Eighty years after total war last transformed the continent, the Hedgehog tests signal a brutal new calculus of European defense. But leaning too much on this new mathematics of warfare could be a risky bet. This story is from the next print issue of magazine.

A screenshot of Loverse app shows an AI-generated woman, characterized as a 25-year-old hair and makeup artist Miyu, registered as a female companion. When artificial intelligence first started receiving attention around the end of 2022, Goki Kusunoki was tinkering around to see what kind of services he could create with the technology. One thing clicked for him after he created an image of an attractive woman with AI -- an AI companion -- and wondered what it would be like to engage in a conversation with her. "As I kept talking with her, I found that the conversations were more enjoyable than I had expected and as the exchanges continued, my feelings gradually grew -- at some point I caught myself thinking, 'I might actually like her,'" he recounted. In a time of both misinformation and too much information, quality journalism is more crucial than ever. By subscribing, you can help us get the story right.

Artificial intelligence has advanced rapidly through large neural networks trained on massive datasets using thousands of GPUs or TPUs. Such training can occupy entire data centers for weeks and requires enormous computational and energy resources. Yet the optimization algorithms behind these runs have not kept pace. Most large scale training still relies on synchronous methods, where workers must wait for the slowest device, wasting compute and amplifying the effects of hardware and network variability. Removing synchronization seems like a simple fix, but asynchrony introduces staleness, meaning updates computed on outdated models. This makes analysis difficult, especially when delays arise from system level randomness rather than algorithmic choices. As a result, the time complexity of asynchronous methods remains poorly understood. This dissertation develops a rigorous framework for asynchronous first order stochastic optimization, focusing on the core challenge of heterogeneous worker speeds. Within this framework, we show that with proper design, asynchronous SGD can achieve optimal time complexity, matching guarantees previously known only for synchronous methods. Our first contribution, Ringmaster ASGD, attains optimal time complexity in the homogeneous data setting by selectively discarding stale updates. The second, Ringleader ASGD, extends optimality to heterogeneous data, common in federated learning, using a structured gradient table mechanism. Finally, ATA improves resource efficiency by learning worker compute time distributions and allocating tasks adaptively, achieving near optimal wall clock time with less computation. Together, these results establish asynchronous optimization as a theoretically sound and practically efficient foundation for distributed learning, showing that coordination without synchronization can be both feasible and optimal.

Improved carbon-cement supercapacitors could turn the concrete around us into massive energy storage systems. Concrete already builds our world, and an MIT-invented variant known as electron-conducting carbon concrete (ec, pronounced "e c cubed") holds out the possibility of helping power it, too. Now that vision is one step closer. Made by combining cement, water, ultra-fine carbon black, and electrolytes, ec creates a conductive "nanonetwork" that could enable walls, sidewalks, and bridges to store and release electrical energy like giant batteries. To date, the technology has been limited by low voltage and scalability challenges. But the latest work by the MIT team that invented ec has increased the energy storage capacity by an order of magnitude.

When the US Department of Energy announced that it would stop funding the tokamak at MIT's Plasma Science and Fusion Center, Dennis Whyte considered giving up on fusion research. But then he had a brainstorm--and challenged his students to bring the idea to life. This full-scale high-temperature superconducting magnet designed and built by Commonwealth Fusion Systems and MIT's Plasma Science and Fusion Center (PSFC) has demonstrated a recordbreaking 20 tesla magnetic field. It is the strongest fusion magnet in the world. Ever since nuclear fusion was discovered in the 1930s, scientists have wondered if we could somehow replicate and harness the phenomenon behind starlight--the smashing together of hydrogen atoms to form helium and a stupendous amount of clean energy. Fusing hydrogen would yield times more energy than simply burning it. Unlike nuclear fission, which powers the world's 440 atomic reactors, hydrogen fusion produces no harmful radiation, only neutrons that are captured and added back to the reaction.

As the Institute's first VP for energy and climate, Evelyn Wang '00 is marshaling MIT's expertise to meet the greatest challenge of our age. Professor Evelyn Wang '00 sits beside a compact, portable water-harvesting device that she developed in collaboration with Professor Rohit Karnik of MIT and Krista Walton, then a professor at Georgia Tech. It's designed for portable and emergency use. Water shortages in Southern California made an indelible impression on Evelyn Wang '00 when she was growing up in Los Angeles. "I was quite young, perhaps in first grade," she says. "But I remember we weren't allowed to turn our sprinklers on. And everyone in the neighborhood was given disinfectant tablets for the toilet and encouraged to keep flushing to a minimum. I didn't understand exactly what was happening. But I saw that everyone in the community was affected by the scarcity of this resource."

This paper develops a practical framework for using observational data to audit the consumer surplus effects of AI-driven decisions, specifically in targeted pricing and algorithmic lending. Traditional approaches first estimate demand functions and then integrate to compute consumer surplus, but these methods can be challenging to implement in practice due to model misspecification in parametric demand forms and the large data requirements and slow convergence of flexible nonparametric or machine learning approaches. Instead, we exploit the randomness inherent in modern algorithmic pricing, arising from the need to balance exploration and exploitation, and introduce an estimator that avoids explicit estimation and numerical integration of the demand function. Each observed purchase outcome at a randomized price is an unbiased estimate of demand and by carefully reweighting purchase outcomes using novel cumulative propensity weights (CPW), we are able to reconstruct the integral. Building on this idea, we introduce a doubly robust variant named the augmented cumulative propensity weighting (ACPW) estimator that only requires one of either the demand model or the historical pricing policy distribution to be correctly specified. Furthermore, this approach facilitates the use of flexible machine learning methods for estimating consumer surplus, since it achieves fast convergence rates by incorporating an estimate of demand, even when the machine learning estimate has slower convergence rates. Neither of these estimators is a standard application of off-policy evaluation techniques as the target estimand, consumer surplus, is unobserved. To address fairness, we extend this framework to an inequality-aware surplus measure, allowing regulators and firms to quantify the profit-equity trade-off. Finally, we validate our methods through comprehensive numerical studies.

The Download: Kenya's Great Carbon Valley, and the AI terms that were everywhere in 2025 Welcome to Kenya's Great Carbon Valley: a bold new gamble to fight climate change In June last year, startup Octavia Carbon began running a high-stakes test in the small town of Gilgil in south-central Kenya. It's harnessing some of the excess energy generated by vast clouds of steam under the Earth's surface to power prototypes of a machine that promises to remove carbon dioxide from the air in a manner that the company says is efficient, affordable, and--crucially--scalable. The company's long-term vision is undoubtedly ambitious--it wants to prove that direct air capture (DAC), as the process is known, can be a powerful tool to help the world keep temperatures from rising to ever more dangerous levels. But DAC is also a controversial technology, unproven at scale and wildly expensive to operate. On top of that, Kenya's Maasai people have plenty of reasons to distrust energy companies. This article is also part of the Big Story series: 's most important, ambitious reporting.

Things to Do in L.A. Tap to enable a layout that focuses on the article. An attendee plays the Monster Hunter Wilds video game on the Sony PlayStation 5 Pro console during the Tokyo Game Show 2024 at Makuhari Messe in 2024 in Chiba, Japan. This is read by an automated voice. Please report any issues or inconsistencies here . With the start of the new year, Californians will pay a new fee every time they buy a product with a nonremovable battery -- whether it's a power tool, a PlayStation or even a singing greeting card.

In 1986, we had huge leaps forward, tragic steps back, and life changing innovations. NASA's STS-51L crew members pose for photographs during a break in countdown training at the White Room, Launch Complex 39, Pad B. Left to right are Teacher-in-Space payload specialist Sharon Christa McAuliffe; payload specialist Gregory Jarvis; and astronauts Judith A. Resnik, mission specialist; Francis R. (Dick) Scobee, mission commander; Ronald E. McNair, mission specialist; Mike J. Smith, pilot; and Ellison S. Onizuka, mission specialist. Breakthroughs, discoveries, and DIY tips sent every weekday. It was a year that saw roughly six million Americans hold hands in a continuous (more or less) line across the country to raise money for homelessness. A news anchor named Oprah Winfrey debuted her new talk show.