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Gamma Cas (B0.5IVe) is the noted prototype of a subgroup of classical Be stars exhibiting hard thermal X-ray emission. This paper reports results from a 23-year optical campaign with an Automated Photometric Telescope (APT) on this star. A series of unstable long cycles of length 56--91 days has nearly ceased over the last decade. Herein, we revise the frequency of the dominant coherent signal at 0.82238 cy/d. This signal's amplitude has nearly disappeared in the last 15 years but has somewhat recovered its former strength. We confirm the presence of secondary nonradial pulsation signals found by other authors at frequencies 1.25, 2.48, and 5.03 cy/d. The APT data from intensively monitored nights reveal rapidly variable amplitudes among these frequencies. We show that peculiarities in the 0.82 cy/d waveform exist that can vary even over several days. Although the 0.82 cy/d frequency is near the star's presumed rotation frequency. However, because of its phase slippage with respect to a dip pattern in the star's far-UV light curve it is preferable to consider the latter pattern, not the 0.82 cy/d signal, that carries a rotation signature. We also find hints of the UV dip pattern in
We outline a definition of accessible and presentable objects in a 2-category $\mathcal K$ endowed with a "KZ context", that is to say a pair of lax-idempotent monads interacting in a prescribed way; this perspective suggests a unified treatment of many "Gabriel-Ulmer like" theorems, asserting how presentable objects arise as reflections of generating ones. We outline the notion of "(Gabriel-Ulmer) envelope" for a KZ context, sufficient to concoct Gabriel-Ulmer duality. We end the paper with a roundup of examples, involving classical (set-based and enriched), low dimensional category theory, and a perspective for future work, rooted in higher category theory and homotopy theory.
A decades-old puzzle about water has finally been unraveled。 Researchers found that water trapped in tiny nanoscale spaces is not inherently more reactive。 Instead, the intense pressures created inside these microscopic gaps explain most of the effect, while the surrounding material can further enhance water's chemistry if it interacts with the rea
The discovery underscores the increased effort being poured into Mac infostealers
A newly proposed quantum sensing technique could make it much easier to identify one of physics’ newest and most intriguing classes of magnets: altermagnets。 These unusual materials, discovered only a few years ago, appear to combine the speed and efficiency of antiferromagnets with some of the useful electronic properties of traditional magnets, m
NASA’s upgraded Cold Atom Lab is turning the International Space Station into a frontier for quantum research, creating ultra-cold matter that behaves in astonishing ways。 The experiments could unlock new discoveries about the universe while paving the way for powerful future technologies in space and on Earth
A groundbreaking superconducting X-ray spectrometer has begun operation at BESSY II, giving Europe its first TES-based system and boosting photon detection efficiency by up to 1,000 times。 The advance enables scientists to explore atomically thin materials, nanostructures, and ultra-dilute samples with remarkable speed and sensitivity
A new sunlight-powered material can convert visible light into higher-energy UV light, overcoming a challenge that has frustrated scientists for years。 The breakthrough could enable cleaner air purification, solar-driven chemistry, and advanced manufacturing technologies using nothing more than natural sunlight
Researchers found that twisting layered sheets of hexagonal boron nitride can dramatically change the light produced by quantum emitters embedded within the material。 The technique offers an unexpected new level of control over components that could power future quantum computers, communications systems, and sensors
A new study suggests Earth may have been sending tiny hitchhikers to Venus for billions of years。 Researchers found that asteroid impacts could launch microbes into space, where some might survive the journey and end up suspended in Venus' clouds。 If future missions detect life there, there's a surprising chance it didn't originate on Venus at all—
The global cobalt supply chain is more interconnected—and more vulnerable—than previously thought, with disruptions capable of triggering far-reaching cascades across multiple countries and industries。 Researchers warn that protecting battery supply chains will require system-wide coordination because critical bottlenecks can turn local shocks into
NASA’s Lucy spacecraft discovered that asteroid Donaldjohanson is a wobbling, peanut-shaped relic born from a violent collision and slowly reshaped by the subtle force of sunlight。 It also carries traces of ancient water, making it an important clue to the solar system’s mysterious past
Quantum mechanics has journeyed from a strange and controversial idea to the foundation of some of humanity’s most advanced technologies。 Now researchers are pushing its boundaries even further, with potential breakthroughs in energy, medicine, computing, and our understanding of the universe
Researchers found that a Chinese sodium-ion battery performs far better than expected, with production quality and design features comparable to Tesla’s batteries。 If engineers can improve cold-weather charging and energy density, sodium could become a cheaper and more abundant alternative to lithium for EVs and large-scale energy storage