When a front tooth has been root-treated and has lost a large portion of its original structure, restoring it is one of dentistry's more demanding challenges. The traditional approach involves inserting a post down into the root canal, building up a core on top of it, and then placing a crown — a technique that works but requires removing further tooth material, sometimes weakening what little remains and raising the risk of a root fracture that cannot be repaired. A newer, less invasive option called an endocrown skips the post altogether, drawing its hold entirely from the pulp chamber — the hollow space left after root canal treatment — and covering the tooth with a single ceramic restoration.

A large-scale study of human mobility and wildlife movement across the United States suggests that the day-to-day presence of humans – not just how they alter the landscape – is a major ecological force that shapes how animals move through and use their environments, researchers report. Human activity is accelerating global biodiversity loss by transforming climates and rapidly reshaping natural landscapes. Yet beyond these physical alterations of the environment, there is a growing recognition that the direct presence of humans themselves may greatly influence how animals behave, including how they perceive risk, move through their habitats, compete for resources, and interact with other species. Despite this, large-scale comparative research has rarely examined human presence as a distinct and dynamic pressure on wildlife, largely due to the fact that detailed data on where and when people move are difficult to obtain. Most existing studies have focused on local settings or broad proxies of human presence, such as pandemic-related lockdowns, and have concentrated largely on mammals. As a result, relatively little is known about how interacting forms of human activity and presence combine to affect wildlife.

 

To address this gap, Ruth Oliver and colleagues combined data on numbers of mobile devices and vehicles in each U.S. census block as a measure of human presence, along with detailed measures of human landscape modification, with animal tracking data from more than 4,500 birds and mammals representing 37 species. By centering their study on the years 2019 and 2020 and leveraging the unique, temporary decline of human movement in modified landscapes during the COVID-19 pandemic, Oliver et al. were able to disentangle the direct effects of human activity from the broader impacts of landscape change and evaluate how each factor influenced the amount of space animals used. According to the findings, direct human presence influenced the movement patterns or use of the environment of 65% of species examined. Many mammals reduced the amount of territory they used in response to greater human activity, particularly in less-developed habitats where animals may perceive humans as a threat. On the other hand, some species, like gray wolves, expanded their ranges, likely to better avoid people. Adaptable species such as white-tailed deer appeared more comfortable incorporating human-modified environments into their usable habitats. Birds likewise showed highly variable responses, with some species becoming more spatially constrained and others altering their habitat use depending on the surrounding degree of development. In a related Perspective, Lydia Beaudrot discusses the study and its findings in greater detail.

Using observations from the James Webb Space Telescope (JWST), researchers have identified cloudy “mornings” and clear “evenings” on a distant gas giant exoplanet. The findings suggest that the planet’s atmospheric aerosols are dominated by condensation-driven clouds that form, circulate, and evaporate as they move through extreme temperature contrasts across the planet. Aerosols play an important role in shaping the appearance, chemistry, and temperature of exoplanet atmospheres. However, there is limited information about the nature of these particles, including their atmospheric distribution or the physical processes that determine their properties. In hot Jupiters – a class of gas giant exoplanets that are physically similar to Jupiter – it has long been debated whether atmospheric aerosols are primarily mineral clouds formed through condensation or photochemical hazes generated by intense stellar radiation. Because they can obscure or distort spectral signals, they also complicate efforts to determine the chemical composition of distant worlds.

 

Here, Sagnick Mukherjee and colleagues used the Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST to observe the tidally locked, hot Jupiter exoplanet, WASP-94A b, and analyzed the light passing separately through the planet’s “morning” and “evening” atmospheric horizons. The findings revealed stark differences between the two hemispheres: the cooler morning side appeared heavily shrouded in high-mineral clouds that obscure gaseous signatures, while the hotter evening side is comparatively clear and shows strong water vapor absorption. According to Mukherjee et al., this pattern suggests that the planet’s aerosols are dominated by clouds formed through condensation rather than photochemical processes. Moreover, further analysis using a 3D general circulation model indicates a dynamic cloud cycle driven by extreme temperature contrasts of roughly 450 degrees Kelvin between the planet’s two hemispheres. Clouds appear to form on the cooler night side of the planet, circulate toward the morning side, and then evaporate as they move into the intensely heated day side. According to Mukherjee et al., the findings warn that treating an exoplanet’s atmosphere as uniform, which is a common simplifying assumption, can significantly distort or bias estimates of their chemistry and physical properties, and suggest that previous measurements of exoplanet atmospheres may need to be reconsidered to account for complex, asymmetric weather systems.

A new large-scale study led by a research team from the Yale Center for Biodiversity and Global Change has found that wildlife responds not only to how humans reshape their habitats, but also to the simple presence of humans — and sometimes in surprising ways.

 

Even small changes in how people move through environments can significantly affect animal behavior and could have implications for wildlife conservation efforts, the study finds.

 

“Our findings provide an important nuance in our understanding of wildlife in a rapidly changing world,” said Walter Jetz, a professor of ecology and evolutionary biology in Yale’s Faculty of Arts and Sciences and director of the Yale Center for Biodiversity and Global Change.

 

“Animals are affected by both direct human presence and by human-caused changes to the physical environment, such as agriculture and urbanization,” Jetz said. “This study is the first to directly assess at scale how both causes, separately and in combination

Suppose there are signs of extraterrestrial life and we have not yet been able to detect them. What does that mean? In the renowned journal Nature Astronomy, researchers discuss the consequences of these so-called false-negative results. “We are currently investing a great deal of money in missions that might need to be designed differently.”