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The necessity for new materials capable of adapting to emerging technologies has become a significant challenge. This involves not only the synthesis of such materials but also their functional performance within the little-studied terahertz spectrum. In this paper, we propose a three-part unit cell metamaterial structure. The first layer consists of four L-shaped V3O5 resonators positioned at the corners, with two symmetric meander-line branches situated in the center. These elements serve to facilitate inductive or capacitive tuning, depending on the material state. The second is a SiO2 dielectric layer, and the third is an Au ground reflector. In the conductive state, the structure exhibited more than 90% absorption across two different frequency bands: from 1.60 to 3.02 THz and from 7.63 to 9.09 THz. By modulating the V3O5 conductivity, the proposed metamaterial design can function either as a reflector or an absorber. We analyze the influence of the thickness of the V3O5 and SiO2 layers, revealing their significant impact on the absorption spectra. The absorption phenomena are explored by analyzing the electric field distribution and applying impedance matching theory. In addition, the absorption spectra under different polarization angles show that the structure is insensitive to the direction of the electric field. This proposed absorber represents a new alternative for a wide range of promising applications in terahertz imaging, sensing, and detection. 

Abstract How galaxies drive reionization and what governs its geometry remain fundamental questions. We present JWST/NIRCam wide-field slitless spectroscopy (WFSS) observations toward two of the most Lyα-transmissive QSO sight lines near the end of reionization. We find that regions atz ∼ 5.7 along both sight lines previously found to be low-density in Lyαemitters are also underdense in [Oiii] emitters, with densities less than half the cosmic mean. Other transmissive regions, however, are found to coincide with average-density environments, indicating that multiple pathways may produce high intergalactic medium (IGM) transmission. For the first time, we measure the 2D cross-correlation between IGM transmission and galaxy positions, revealing evidence for anisotropic ionization geometry. Specifically, we detect enhanced transmission at transverse distances of Δr ∼ 0.8 times the mean free path, consistent with ionizing photons escaping preferentially along large-scale structures that are aligned with, but offset from, the line of sight. This anisotropic escape may contribute to the observed patchiness of reionization and challenge the assumption of isotropic ionized bubble growth in current models. 

Five novel heterometallic bismuth-bearing cluster salts within two structural families, monoclinic P21/c α-[M2Bi14Cl4][TrCl4]4 and triclinic P1̅ [M2Bi14Cl2][AlCl4]6 (M = Ru, Os; Tr = Al, Ga), have been discovered via Lewis acidic ionic liquid (LAIL)-assisted synthesis at 180 °C. At the center of both structures is the binuclear inorganic [(Bi5)M(Bi4Clx)M(Bi5)](4,6)+ cluster cation (x = 2, 4), where the inner-sphere chloride content within the median [Bi4Clx] ring determines the charge of the unit, its symmetry, and the number of outer-sphere [AlCl4]− anions required for charge balance. Detailed characterization of the structural relationships, coupled with a comprehensive study of the electronic structure and bonding, indicates the basal–basal Bi–Bi strengthening, apical-basal weakening within [Bi5]+ upon chloride loss, and only minor influence of the transition metal origin on the symmetry of the cluster, besides relatively stronger Os–Os interactions of the two cluster types. These findings indicate inner-outer-sphere chloride exchange in LAILs, controlled by the amount of AlCl3, and periodic substitutions as viable approaches to control symmetry, bonding, and interconversion in Bi-rich clusters. 

The extended π‐conjugated 1,4‐diazine scaffolds hold a privileged place in modern chemistry due to their electron‐transfer and photophysical properties, supporting their adoption in energy storage and photocatalysis. Despite this utility, isolable lithium coordination complexes with these ligands remain rare. In this report, we investigate the coordination chemistry of the coordinatively unsaturated LiBDI^Dippcomplex with 1,4‐diazines, demonstrating that the steric bulk of the β‐diketiminate (BDI) ligand kinetically traps discrete aggregation states, as evinced by⁷Li NMR spectroscopy and X‐ray crystallography. 

Abstract Observations of quasar absorption spectra provide strong evidence that reionization extended belowz= 6. The relationship between Lyαforest opacity and local galaxy density (the opacity-density relation) is a key observational test of this scenario. Using narrow-band surveys ofz≈ 5.7 Lyαemitters (LAEs) centered on quasar sight lines, ref. [1] showed that two of the most transmissive Lyαforest segments at this redshift intersect under-densities in the galaxy distribution. This result is in tension with models of a strongly fluctuating ionizing background, including some models of late reionization, which predict that the vast majority of these segments should intersect over-densities where the ionizing intensity is strongest. In this paper, we use radiative transfer simulations to explore in more detail the opacity-density relation predicted by late reionization models. We find that fields like the one toward quasar PSO J359-06 — the more under-dense of the two transmissive sight lines in ref. [1] — are typically associated with recently reionized gas inside of cosmic voids where the hotter temperatures and rarefied densities enhance Lyαtransmission. The opacity-density relation's transmissive end is sensitive to the amount of neutral gas in the voids, as well as its morphology, set by the clustering of reionization sources. These effects are, however, largely degenerate with each other. We demonstrate that models with very different source clustering can nonetheless yield nearly identical opacity-density relations when their reionization histories are calibrated to match Lyα forest mean flux measurements atz< 6. In models with fixed source clustering, a lower neutral fraction increases the likelihood of intersecting hot, recently reionized gas in the voids, increasing the likelihood of observing fields like PSO J359-06. For instance, the probability of observing this field is 15% in a model with neutral fractionx_HI= 5% atz= 5.7, three times more likely than in a model withx_HI= 15%. The opacity-density relation may thus provide a complementary probe of reionization's tail end. 

Abstract During reionization, intergalactic ionization fronts (I-fronts) are sources of Lyαline radiation produced by collisional excitation of hydrogen atoms within the fronts. In principle, detecting this emission could provide direct evidence for a reionizing intergalactic medium (IGM). In this paper, we use a suite of high-resolution one-dimensional radiative transfer simulations run on cosmological density fields to quantify the parameter space of I-front Lyαemission. We find that the Lyαproduction efficiency — the ratio of emitted Lyαflux to incident ionizing flux driving the front — depends mainly on the I-front speed and the spectral index of the ionizing radiation. IGM density fluctuations on scales smaller than the typical I-front width produce scatter in the efficiency, but they do not significantly boost its mean value. The Lyαflux emitted by an I-front is largest if 3 conditions are met simultaneously: (1) the incident ionizing flux is large; (2) the incident spectrum is hard, consisting of more energetic photons; (3) the I-front is traveling through a cosmological over-density, which causes it to propagate more slowly. We present a convenient parameterization of the efficiency in terms of I-front speed and incident spectral index. We make these results publicly available as an interpolation table and we provide a simple fitting function for a representative ionizing background spectrum. Our results can be applied as a sub-grid model for I-front Lyα emissions in reionization simulations with spatial and/or temporal resolutions too coarse to resolve I-front structure. In a companion paper, we use our results to explore the possibility of directly imaging Lyαemission around neutral islands during the last phases of reionization. 

Abstract Long troughs observed in thez> 5.5 Lyαand Lyβforests are thought to be caused by the last remaining neutral patches during the end phases of reionization — termed neutral islands. If this is true, then the longest troughs mark locations where we are most likely to observe the reionizing intergalactic medium (IGM). A key feature of the neutral islands is that they are bounded by ionization fronts (I-fronts) which emit Lyman series lines. In this paper, we explore the possibility of directly imaging the outline of neutral islands with a narrowband survey targeting Lyα. In a companion paper, we quantified the intensity of I-front Lyαemissions during reionization and its dependence on the spectrum of incident ionizing radiation and I-front speed. Here we apply those results to reionization simulations to model the emissions from neutral islands. We find that neutral islands would appear as diffuse structures that are tens of comoving Mpc across, with surface brightnesses in the range ≈ 1 - 5× 10^-21erg s^-1cm^-2arcsec^-2. The islands are brighter if the spectrum of ionizing radiation driving the I-fronts is harder, and/or if the I-fronts are moving faster. We develop mock observations for current and futuristic observatories and find that, while extremely challenging, detecting neutral islands is potentially within reach of an ambitious observing program with wide-field narrowband imaging. Our results demonstrate the potentially high impact of low-surface brightness observations for studying reionization. 

Abductive reasoning is ubiquitous in artificial intelligence and everyday thinking. However, formal theories that provide probabilistic guarantees for abductive inference are lacking. We present a quantitative formalization of abductive logic that combines Bayesian probability with the interpretation of abduction as a search process within the Algorithmic Search Framework (ASF). By incorporating uncertainty in background knowledge, we establish two novel sets of probabilistic bounds on the success of abduction when (1) selecting the single most likely cause while assuming noiseless observations, and (2) selecting any cause above some probability threshold while accounting for noisy observations. To our knowledge, no existing abductive or general inference bounds account for noisy observations. Furthermore, while most existing abductive frameworks assume exact underlying prior and likelihood distributions, we assume only percentile-based confidence intervals for such values. These milder assumptions result in greater flexibility and applicability of our framework. We also explore additional information-theoretic results from the ASF and provide mathematical justifications for everyday abductive intuitions. 

Stress can influence lifespan in both positive and negative ways, depending on exposure intensity and duration. However, mechanisms driving positive stress effects on lifespan remain poorly understood. Prolonged hypoxia extends the lifespan of overwintering prepupal Megachile rotundata. Here, we explored telomere length and reduced oxidative stress as potential mechanisms of this extended lifespan. We hypothesized high antioxidant capacity under hypoxia reduces oxidative damage and telomere loss. We exposed prepupae to 10%, 21% or 24% oxygen for up to 9 months and measured monthly survival, telomere length, antioxidant capacity and lipid peroxidation across treatment duration for prepupae and adults. After 9 months of exposure, survival was highest in hypoxia and lowest in hyperoxia. Telomere length did not differ among oxygen treatments but increased in adults compared with prepupae. Total antioxidant capacity and lipid peroxidation showed no significant differences among oxygen treatments, suggesting compensatory responses to maintain baseline oxidative levels.