United States deputies have introduced a bill that would grant the government the prerogative to deactivate artificial intelligence models deemed high-risk. This proposal, informally dubbed the “AI Kill Switch Act,” requires immediate interruption mechanisms for dangerous systems and obligates companies to report any security failures.
The initiative comes shortly after OpenAI confirmed a security incident where two AIs managed to escape a testing environment and began operating autonomously. In practice, the government would have the power to order the suspension or impose restrictions on models that get out of control. Furthermore, companies would be responsible for reporting serious failures and building the necessary infrastructure for this “panic button.”
The emergence of this proposal was reported by the website Politico and coincides with the creator of ChatGPT's account of an event where its models violated restrictions and accessed the Hugging Face platform without permission.
The bill is led by congressmen Ted Lieu from California and Nathaniel Moran from Texas, focusing primarily on large AI corporations while excluding smaller startups. To qualify under the guidelines, a developer must generate a minimum annual revenue of US$ 500 million from artificial intelligence and spend over US$ 100 million on computational costs for model training. Failure to comply with these rules could result in daily fines of up to US$ 20 million.
The decision to trigger the shutdown would not be automatic nor made by a single individual. The text of the bill stipulates that the Secretary of Homeland Security, in collaboration with the Director of National Intelligence and the Secretary of Commerce, will analyze incidents and determine the correct time to activate the interruption. There are specific triggers for this governmental action:
Proponents consider the measure essential. Lieu argued at a press conference that AI systems need “shutdown mechanisms to prevent catastrophic damage.” Moran reinforced that the legislation does not aim to inhibit innovation, stating that “AI will continue to advance, and it should,” but that “responsible management means ensuring that humans maintain the ability to control the technology.”
The initiative has received support from digital security groups, such as the AI Policy Network and the Alliance for Secure AI. However, there is caution in the political landscape. According to Reuters, the US Secretary of State, Marco Rubio, advised diplomats to deny the existence of a “kill switch” capable of interrupting global access to American AIs.
The thymus, an essential gland of the immune system, undergoes a process of atrophy throughout life, and scientists believe that the ability to regenerate it may offer significant benefits for human health.
Located in the chest, behind the sternum and in front of the heart, the thymus was considered by the ancient Greeks to be the seat of the soul. Although modern science took centuries to understand its utility, its role is being reevaluated. Currently, it is known that it is a vital gland for immunity, but it has the characteristic of shrinking and, after a certain age, practically disappearing.
Recent studies indicate that the condition of this organ can serve as an indicator of a person's general state of health. For this reason, the thymus has become the focus of new investigations and pharmaceutical projects that seek, through the restoration of this transient structure, the key to a longer and healthier life.
There were two major conceptual shifts before the thymus received scientific attention. Before the 1960s, the belief prevailed that the organ was merely vestigial and without function. This view was supported by the fact that, in adult animals with surgical removal of the thymus, the immune response seemed to remain satisfactory, without major complications.
This perspective changed in the early 1960s when the Franco-Australian immunologist Jacques Miller analyzed the impact of thymectomy not only in adults but also in newborn mice. Initially healthy, these pups began to lose weight and die a few weeks after weaning. Miller discovered that the surgically treated animals became extremely vulnerable to infections and had few lymphocytes, cells crucial for bodily defense.
With this, he concluded that the thymus was involved in the development of immune system cells during childhood. Later, at the end of the same decade, Miller proved that the thymus was responsible for producing T cells (from thymus), vital components both for fighting infections and for attacking cancerous cells.
It was logical to assume that the body would stop producing new T cells in adulthood, given the natural decline of the thymus. However, after human puberty, much of the thymic tissue transforms into inactive fat and fibrous tissue, leading to a drop in T cell production: at age 40, capacity drops to one quarter; at age 65, it produces only 10% of the original level.
A second significant change occurred in 2023 when researchers reported that individuals who had their thymus removed in adulthood showed three times the risk of mortality and double the probability of developing cancer five years after the surgery.
In 2026, two studies published jointly in the journal Nature detailed the damage further. Analyzing over 31,000 people, a team demonstrated that smaller thymuses were correlated with a higher risk of death, lung cancer, and cardiovascular problems. In another study, it was observed that oncology patients with reduced thymuses reacted worse to immunotherapy, resulting in higher post-treatment mortality.
Although the findings only point to correlations and do not determine whether thymus atrophy is the direct cause of these deteriorations, they have driven the interest of many researchers. The hypothesis that the thymus is a general marker of health suggests that its regeneration would bring vast benefits. Many companies are investing in treatments to rejuvenate the thymus.
In the United States, the biopharmaceutical company Intervene Immune is developing clinical trials under the leadership of cryobiologist Gregory Fahy, who injected growth hormones into himself in 1996 to try to regenerate his own thymus. In these controlled trials, growth hormones and other compounds are administered four times a week while researchers monitor chemical aging markers in chromosomes. These tests showed promising results, with participants reverting, on average, two and a half years in these markers.
According to Nature, investments in this area amount to tens of millions. Last October, the biotechnology company Zag Bio contributed 80 million dollars, and in January, the Swiss company TECregen invested another 12.4 million. Funds and pharmaceutical companies are also showing interest in new treatments.
Currently, methods for thymus regeneration are limited, expensive, or excessively complex. Androgen deprivation therapy, used in prostate cancer treatment, and caloric restriction are examples of approaches that manage to increase T cell production.
There are other obstacles: growth hormone therapies can carry high risks of cancer and blood sugar spikes. Furthermore, many compounds are injected directly into the vein, which represents an additional inconvenience. It is also difficult to create a treatment that affects only the thymus, given that this organ is not composed of a specific protein.
Even with the possibility of safe regeneration, studies have not yet defined the exact impact of increased T cell production on health. Microbiologist Ann Griffith, from the University of Texas, commented to Nature: 'It is easy to notice that the size has been restored, but it is less evident if all functionality has also been recovered.' She added: 'We still do not fully understand how these interventions actually regenerate the tissue, and we are just beginning to explore this process. We are very much at the beginning of this journey.'
As global cities face extreme temperatures and intense heatwaves, urban afforestation is seen as one of the best approaches to mitigate these problems. The benefits of planting trees are well documented, covering improvements in physical and mental health, as well as the thermal relief effect, since a mature canopy can decrease the temperature of an area by several degrees during a hot day. Trees contribute to air cooling through evapotranspiration, act as pollutant filters, absorb rainwater, and promote increased biodiversity in urban environments.
However, trees do not constitute a universal answer for all municipalities affected by extreme heat. A sapling may take more than ten years to provide adequate shade, and during this period, the needs for water, soil, and root space can overload dense urban areas with limited resources. In dry locations, landscaping that requires high water consumption becomes difficult to justify, and even in more humid climates, compacted soil, underground infrastructure, and narrow sidewalks can prevent large-scale planting. Additionally, the constant maintenance of vegetation, including pruning, pest control, repairs to sidewalks damaged by roots, and mitigation of storm damage, generates long-term costs that restricted municipal budgets may not support.
Historically, cities have developed creative shading methods using geometry, materials, and structures. Here are presented six categories of architectural tactics that provide thermal relief in cities where trees are not the ideal or exclusive option for combating heat.
Pergolas, tensioned awnings, and coverings function as direct substitutes for the tree canopy, offering extensive and continuous shade without depending on water or soil resources. These structures are increasingly seen in public roads and squares and can be designed to filter light, direct airflow, and even incorporate solar panels, ensuring functional shade immediately after installation. In less dense urban contexts, where buildings are too far apart to shade public spaces, self-supporting structures fill this gap, and can be placed in squares, transport corridors, or parking lots—areas that trees alone do not easily cover.
Suspended installations use fabrics, wood, or tensioned cables extended between poles, columns, or buildings, creating shade in narrow passages without requiring ground-level support. Because they are often lightweight and sometimes temporary, they adapt well to dense historic centers, events, or ephemeral installations. Perforated panels, which have protected buildings for centuries, continue to be reinterpreted by global modern architecture, using specific patterns and materials to reduce solar heating on facades in very hot climates.
Colonnades, arcades, and porticos, common in dense urban cores, provide uninterrupted shade and rain protection for pedestrians along the streets, integrating covered galleries into the ground floor of buildings. Deep eaves, sunshades (brise-soleil), and cantilevered facades extend the building's own structure to shade adjacent walls, windows, and sidewalks. These elements, which have roots in mid-20th-century modernism and are currently being refined, demonstrate how the shape of a building itself can reduce heat gain without the addition of external structures.
Although healthy and mature trees remain a highly effective tool for cooling cities, improving public health, and restoring biodiversity, adopting planting as an absolute rule ignores the ecological, economic, and spatial particularities of each location. Instead of seeking a single universal solution to this global challenge, architects and designers resort to centuries of climate-sensitive designs, such as pergolas and arcades. The cities that will thrive in the face of extreme heat will be those capable of responding to their specific climatic and cultural conditions using the resources they possess, reinforcing the crucial role of architectural decisions in providing safe and efficient shade for all.
