We report a $z=2.30$ galaxy protocluster (COSTCO-I) in the COSMOS field, where the Lyman-$α$ forest as seen in the CLAMATO IGM tomography survey does not show significant absorption. This departs from the transmission-density relationship (often dubbed the fluctuating Gunn-Peterson approximation; FGPA) usually expected to hold at this epoch, which would lead one to predict strong Ly$α$ absorption at the overdensity. For comparison, we generate mock Lyman-$α$ forest maps by applying FGPA to constrained simulations of the COSMOS density field, and create mocks that incorporate the effects of finite sightline sampling, pixel noise, and Wiener filtering. Averaged over $r=15\,h^{-1}\,\mathrm{Mpc}$ around the protocluster, the observed Lyman-$α$ forest is consistently more transparent in the real data than in the mocks, indicating a rejection of the null hypothesis that the gas in COSTCO-I follows FGPA ($p=0.0026$, or $2.79 σ$ significance). It suggests that the large-scale gas associated with COSTCO-I is being heated above the expectations of FGPA, which might be due to either large-scale AGN jet feedback or early gravitational shock heating. COSTCO-I is the first known large-scale regi
I investigate the peculiar situation in which I find myself healthy and strong, with a darling family, stimulating job, top-notch dental plan, and living far from active war and wildfire zones -- yet perpetually ill at ease and prone to sudden-onset exasperation when absolutely nothing has happened. My triggers include dinner parties, chairs, therapists, and shopping at Costco. In analysing this phenomenon, I consider epigenetics, the neuroscience of neuroticism, and possible environmental factors such as NSF grant budgets. Yet no obvious solution emerges. Fortunately, my affliction isn't really all that serious. In fact, it's good writing material. So while I'm open to better ideas, I figure I'll just continue being like this.
The intergalactic medium (IGM) in the vicinity of galaxy protoclusters are interesting testbeds to study complex baryonic effects such as gravitational shocks and feedback. Here, we utilize hydrodynamical simulations from the SIMBA and The Three Hundred suites to study the mechanisms influencing large-scale Lyman-$α$ transmission in $2<z<2.5$ protoclusters. We focus on the matter overdensity-Lyman-$α$ transmission relation $(δ_m-δ_F)$ on Megaparsec-scales in these protoclusters, which is hypothesized to be sensitive to the feedback implementations. The lower-density regions represented by the SIMBA-100 cosmological volume trace the power-law $δ_m-δ_F$ relationship often known as the fluctuating Gunn-Peterson approximation. This trend is continued into higher-density regions covered by simulations that implement stellar feedback only. Simulations with AGN thermal and AGN jet feedback , however, exhibit progressively more Lyman-$α$ transmission at fixed matter overdensity. Compared with the 7 protoclusters observed in the COSMOS field, only 2 display the excess absorption expected from protoclusters. The others exhibit deviations: 4 show some increased transparency suggested by
We aim to provably complete a sparse and highly-missing tensor in the presence of covariate information along tensor modes. Our motivation comes from online advertising where users click-through-rates (CTR) on ads over various devices form a CTR tensor that has about 96% missing entries and has many zeros on non-missing entries, which makes the standalone tensor completion method unsatisfactory. Beside the CTR tensor, additional ad features or user characteristics are often available. In this paper, we propose Covariate-assisted Sparse Tensor Completion (COSTCO) to incorporate covariate information for the recovery of the sparse tensor. The key idea is to jointly extract latent components from both the tensor and the covariate matrix to learn a synthetic representation. Theoretically, we derive the error bound for the recovered tensor components and explicitly quantify the improvements on both the reveal probability condition and the tensor recovery accuracy due to covariates. Finally, we apply COSTCO to an advertisement dataset consisting of a CTR tensor and ad covariate matrix, leading to 23% accuracy improvement over the baseline. An important by-product is that ad latent compon
In this paper, we propose a methodology for estimating the crowd speed using WiFi devices without relying on people to carry any device. Our approach not only enables speed estimation in the region where WiFi links are, but also in the adjacent possibly WiFi-free regions. More specifically, we use a pair of WiFi links in one region, whose RSSI measurements are then used to estimate the crowd speed, not only in this region, but also in adjacent WiFi-free regions. We first prove how the cross-correlation and the probability of crossing the two links implicitly carry key information about the pedestrian speeds and develop a mathematical model to relate them to pedestrian speeds. We then validate our approach with 108 experiments, in both indoor and outdoor, where up to 10 people walk in two adjacent areas, with variety of speeds per region, showing that our framework can accurately estimate these speeds with only a pair of WiFi links in one region. For instance, the NMSE over all experiments is 0.18. We also evaluate our framework in a museum-type setting and estimate the popularity of different exhibits. We finally run experiments in an aisle in Costco, estimating key attributes of b
Ancient asteroid impacts may have done more than reshape Earth's surface—they could have helped spark life itself。 New computer models show the collisions created enormous underground hydrothermal systems by cracking the planet's crust and allowing hot water to flow through it。 These long-lasting, life-friendly environments may have covered much of
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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
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Astronomers have finally cracked the mystery of the famous “Pink Planet,” a strange world 57 light-years away that has puzzled scientists for more than a decade。 Using the James Webb Space Telescope, researchers discovered that its atmosphere contains water vapor, methane, carbon dioxide, ammonia, and something never directly confirmed before in su
Scientists are raising concerns that we may be overlooking evidence of extraterrestrial life even when it is present。 Hidden biosignatures, limitations in detection technology, and assumptions about what life should look like can all create dangerous false negatives。 The researchers say future missions should focus not only on finding life, but als
Researchers developed a Wordle-solving strategy that succeeds 99% of the time by focusing on information gain rather than likely answers。 The method uses Shannon entropy to identify guesses that reveal the most about the hidden word。 Each guess is designed to slash uncertainty and narrow the possibilities faster
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