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Multienzyme cascades (MECs) have gained much attention in synthetic chemistry but remain far from being a reliable synthetic tool. Here we report a four‐enzyme cascade comprising a cofactor‐independent and a cofactor self‐sustaining bienzymatic modules for the enantioselective benzylic C−H amination of arylalkanes, a challenging transformation from bulk chemicals to high value‐added chiral amines. The two modules were subsequently optimized by enzyme co‐immobilization with microenvironmental tuning, and finally integrated in a gas‐liquid segmented flow system, resulting in simultaneous improvements in enzyme performance, mass transfer, system compatibility, and productivity. The flow system enabled continuous C−H amination of arylalkanes (up to 100 mM) utilizing the sole cofactor NADH (0.5 mM) in >90 % conversion, achieving a high space‐time yield (STY) of 3.6 g ⋅ L−1 ⋅ h−1, which is a 90‐fold increase over the highest value previously reported. [ABSTRACT FROM AUTHOR]

Summary: Acoustic emission or scattering problems naturally involve uncertainties about the sound sources or boundary conditions. This article initiates the study of time domain boundary elements for such stochastic boundary problems for the acoustic wave equation. We present a space‐time stochastic Galerkin boundary element method which is applied to sound‐hard, sound‐soft and absorbing scatterers. Uncertainties in both the sources and the boundary conditions are considered using a polynomial chaos expansion. The numerical experiments illustrate the performance and convergence of the proposed method in model problems and present an application to a problem from traffic noise. [ABSTRACT FROM AUTHOR]

Topological quantum field theories (TQFTs) provide a general, minimal‐assumption language for describing quantum‐state preparation and measurement. They therefore provide a general language in which to express multi‐agent communication protocols, e.g., local operations, classical communication (LOCC) protocols. In the accompanying Part I, we construct LOCC protocols using TQFT, and show that LOCC protocols induce quantum error‐correcting codes (QECCs) on the agent‐environment boundary. Such QECCs can be regarded as implementing or inducing the emergence of spacetimes on such boundaries. Here connection between inter‐agent communication and spacetime is investigated, by exploiting different realizations of TQFT. The authors delved into TQFTs that support on their boundaries spin‐networks as computational systems: these are known as topological quantum neural networks (TQNNs). TQNNs, which have a natural representation as tensor networks, implement QECC. The HaPPY code is recognized to be a paradigmatic example. How generic QECCs, as bulk‐boundary codes, induce effective spacetimes is then shown. The effective spatial and temporal separations that take place in QECC enables LOCC protocols between spatially separated observers. The implementation of QECCs in BF and Chern‐Simons theories are then considered, and QECC‐induced spacetimes are shown to provide the classical redundancy required for LOCC. Finally, the topological M‐theory is considered as an implementation of QECC in higher spacetime dimensions. [ABSTRACT FROM AUTHOR]

The separation of CO activation and C─C coupling enables oxide–zeolite catalyzed tandem reaction toward direct conversion of syngas into light olefins to be a promising alternative for the traditional Fischer–Tropsch process with elevated selectivity. Utilizing controlled mass transfer to match the activation of reactants and the coupling of intermediates presents an appealing strategy to break the limitation on space‐time yield in this tandem process. In this work, ZnCrOx hollow multi‐shelled structures (HoMS) are fabricated to enhance the adsorption and enrichment ability of syngas, thereby strengthening the rate‐determining activation step of reactants and resulting in an accelerated generation of intermediates. When coupled with SAPO zeolite, quintuple‐shelled ZnCrOx HoMS‐based catalysts exhibit a record high C2= ‐C4= space‐time yield of 559 mg·gcat−1·h−1 with a selectivity of 90%. This work demonstrates the advantages of precise nanostructure sculpturing on the mass transfer behavior in the microenvironment and provides a new strategy for highly selective direct conversion of syngas to light olefins, based on efficient activation of reactants and sufficient feeding of intermediates through enrichment effects within HoMS. [ABSTRACT FROM AUTHOR]

A theorem of Llarull says that if a smooth metric g$g$ on the n$n$‐sphere Sn$\mathbb {S}^n$ is bounded below by the standard round metric and the scalar curvature Rg$R_g$ of g$g$ is bounded below by n(n−1)$n (n - 1)$, then the metric g$g$ must be the standard round metric. We prove a spectral Llarull theorem by replacing the bound Rg⩾n(n−1)$R_g \geqslant n (n - 1)$ by a lower bound on the first eigenvalue of an elliptic operator involving the Laplacian and the scalar curvature Rg$R_g$. We utilize two methods: spinor and spacetime harmonic function. [ABSTRACT FROM AUTHOR]

Recent work in quantum gravity has prompted a re‐evaluation of the fundamental nature of spacetime. Spacetime is potentially emergent from non‐spatiotemporal entities posited by a theory of quantum gravity. Recent efforts have sought to interpret the relationship between spacetime and the fundamental entities through a mereological framework. These frameworks propose that spacetime can be conceived as either having non‐spatiotemporal entities as its constituents or being a constituent part of a non‐spatiotemporal structure. I present a roadmap for those interested in exploring the role of composition in understanding the emergence of spacetime. I establish a taxonomy based on four crucial parameters that should be considered when constructing potential mereological models. Subsequently, I connect these models to a range of perspectives found in current literature, with the aim of pinpointing areas that require further exploration. Finally, I identify three potential challenges facing mereological models of spacetime emergence, rooted in issues of mereological harmony, the distinction between continuous and discrete spacetime, and the implications of quantum superposition. [ABSTRACT FROM AUTHOR]

While (2+1)$(2+1)$‐dimensional black holes in the Einstein theory allow for only the anti‐de Sitter (AdS) asymptotic, when the higher curvature correction is tuned on, the asymptotically flat, de Sitter, and AdS cases are included. Here, a detailed study of the stability and quasinormal spectra of the scalar field perturbations around such black holes with all three asymptotics is proposed. Calculations of the frequencies are fulfilled with the help of the 6th order Wentzel–Kramers–Brillouin (WKB) method with Pade approximants, Bernstein polynomial method, and time‐domain integration. Results obtained by all three methods are in a very good agreement in their common range of applicability. When the multipole moment k$k$ is equal to zero, the purely imaginary, i.e., non‐oscillatory, modes dominate in the spectrum for all types of the asymptotic behavior, while the spectrum at higher k$k$ resembles that in four‐dimensional spacetime with the corresponding asymptotic. While (2 + 1)‐dimensional black holes in the Einstein theory allow for only the anti‐de Sitter (AdS) asymptotic, when the higher curvature correction is tuned on, the asymptotically flat, de Sitter, and AdS cases are included. Here, a detailed study of the stability and quasinormal spectra of the scalar field perturbations around such black holes with all three asymptotics is proposed. Calculations of the frequencies are fulfilled with the help of the 6th order Wentzel–Kramers–Brillouin (WKB) method with Pade approximants, Bernstein polynomial method, and time‐domain integration. Results obtained by all three methods are in a very good agreement in their common range of applicability. When the multipole moment k is equal to zero, the purely imaginary, i.e., non‐oscillatory, modes dominate in the spectrum for all types of the asymptotic behavior, while the spectrum at higher k resembles that in four‐dimensional spacetime with the corresponding asymptotic. [ABSTRACT FROM AUTHOR]

Perception not only registers property instances, but also connects with and attributes properties to individual entities—so‐called sensory individuals, or SIs. But what are SIs? The most‐discussed answers are: (i) SIs are ordinary material objects—cohesive, temporally persistent objects extended and bounded in space, and (ii) SIs are locations or regions in spacetime. I will argue for the object view of SIs on the grounds that its rival, the locational view, faces obstacles concerning the relationship between SIs and spacetime: it makes a mystery of perception's representation of SIs as occupying locations in and moving in ordinary spacetime. [ABSTRACT FROM AUTHOR]

This paper extends the definition of the complexity factor for a charged self‐gravitating structure in the background of f(R,T)$f(\mathbf {R},\mathbf {T})$ gravity. For this purpose, the modified Einstein‐Maxwell field equations and the mass function in terms of interior charge are calculated corresponding to a static sphere. The Reissner‐Nordström exterior spacetime and match it with the spherical interior at the hypersurface to determine the junction conditions are adopted then. The curvature tensor is also decomposed orthogonally, resulting in several scalar functions. Only YTF$\mathbf {Y}_{TF}$ encompasses all the required parameters and fulfills the proposed criteria to be the complexity factor for the considered setup is noticed. Moreover, some constraints to minimize the degrees of freedom in the field equations are chosen. To achieve this, complexity‐free constraint with four additional conditions depending on the matter sector that lead to different models is employed. The stability of the developed models is also analyzed in the presence and absence of charge through the standard model R+2ξ3T$\mathbf {R}+2\xi _3\mathbf {T}$ by varying the values of the model parameter ξ3$\xi _3$. The presence of charge in compact models corresponding to Pr=0$\mathrm{P}_r=0$, a polytropic and a linear equation of state make them stable for specific values of ξ3$\xi _3$ is concluded. This paper extends the definition of the complexity factor for a charged self‐gravitating structure in the background of f (R, T) gravity. For this purpose, the modified Einstein‐Maxwell field equations and the mass function in terms of interior charge are calculated corresponding to a static sphere. The Reissner‐Nordström exterior spacetime and match it with the spherical interior at the hypersurface to determine the junction conditions are adopted then. The curvature tensor is also decomposed orthogonally, resulting in several scalar functions. Only YTF encompasses all the required parameters and fulfills the proposed criteria to be the complexity factor for the considered setup is noticed. Moreover, some constraints to minimize the degrees of freedom in the field equations are chosen. To achieve this, complexity‐free constraint with four additional conditions depending on the matter sector that lead to different models is employed. The stability of the developed models is also analyzed in the presence and absence of charge through the standard model R + 2ξ3T by varying the values of the model parameter ξ3. The presence of charge in compact models corresponding to Pr = 0, a polytropic and a linear equation of state make them stable for specific values of ξ3 is concluded. [ABSTRACT FROM AUTHOR]

The magnitude of life on Earth and human limitations hinder the understanding of even the most basic aspects of biodiversity, such as the identity of species inhabiting the Earth, the so‐called Linnean shortfall. Evaluating patterns in species description dates and their relationship with macroecological variables can help guide where taxonomic efforts should be focused. Therefore, we aim to assess the Linnean shortfall in the knowledge of New World coralsnake biodiversity. We modelled species description dates and estimated that approximately one‐third of the coralsnake diversity remains unknown. The undescribed species are evolutionarily closely related to the already described species. Moreover, recently described species in the group have more restricted geographic ranges and tend to be small‐bodied. The western Amazon and the dry diagonal (i.e. Caatinga, Cerrado, and Chaco) are the areas with the oldest description dates. However, assemblages in these areas have the largest average geographic distances to the type locality of their species, suggesting that little taxonomic effort has been dedicated intrinsically to these regions. We suggest that allocating taxonomic efforts to the dry diagonal and the use of integrative taxonomic techniques for better species delimitation are imperative to fill the Linnean shortfall for the New World coralsnakes. [ABSTRACT FROM AUTHOR]

This work develops two temporal second‐order alternating direction implicit (ADI) numerical schemes for solving multidimensional parabolic‐type integrodifferential equations with multi‐term weakly singular Abel kernels. For the two‐dimensional (2D) case, applying the Crank–Nicolson method and product integration rule to discretizations of temporal derivative and integral terms, respectively, and the spatial discretization is proposed using a compact difference formulation combined with the ADI algorithm; for the three‐dimensional case, the method of temporal discretization is the same as the 2D case, and then we employ the standard finite difference in space to construct a fully discrete ADI finite difference scheme. The ADI technique is used to reduce the calculation cost of the high‐dimensional problem. Besides, the stability and convergence of two ADI schemes are rigorously proved by the energy argument, in which the first scheme converges to the order τ2+h14+h24$$ {\tau}^2+{h}_1^4+{h}_2^4 $$, where τ$$ \tau $$, h1$$ {h}_1 $$, and h2$$ {h}_2 $$ denote the time‐space step sizes, respectively, and the second scheme converges to the space‐time second‐order accuracy. Finally, the numerical results verify the correctness of the theoretical analysis and show that the method of this article is competitive with the existing research work. [ABSTRACT FROM AUTHOR]

Space‐time adaptive processor (STAP) has been widely used for global navigation satellite system (GNSS) anti‐jamming receiver due to its good anti‐jamming performance. When direction of satellite is unknown, STAP can be implemented based on power inversion (PI) criterion. However, existing space‐time PI algorithm will introduce tens to hundreds of degrees biases into carrier phase, and sometimes will even cause cycle slips, which will reduce the success rate of ambiguity resolution, ultimately deteriorating positioning accuracy. A distortion‐less carrier phase tracking space‐time PI algorithm is proposed. The main novelty is that the proposed algorithm keeps the coefficients of the temporal taps as real values by imposing constraints on the weights of the antenna array. Several experiments are implemented to verify the effectiveness of the proposed algorithm. For comparison, the results of PI algorithm and minimum variance distortion‐less response (MVDR) algorithm are shown. Results show that when the number, style, and direction of interferences and the direction of GNSS signal vary, different degrees of biases are introduced into carrier phases for the PI and the MVDR algorithm. However, no bias is introduced into the proposed algorithm. As a result, the effectiveness of the proposed algorithm is verified. [ABSTRACT FROM AUTHOR]

We consider anisotropic Kantowski–Sachs cosmology in Weyl integrable spacetime with an ideal gas. We perform a detailed analysis of the dynamics by investigating the stationary points and reconstruct the cosmological history. This analysis gives important information for the initial value problem in Weyl integrable spacetime. We study three cases, in which the scalar field mass depends only on the density of the ideal gas, with or without cosmological constant term, and when there exists an exponential scalar field potential. We conclude that the existence of the nonzero potential function is essential in order that a spatially flat FLRW universe which can describe inflation can be a future attractor. [ABSTRACT FROM AUTHOR]

Nowadays, alternative gravity is a crucial tool for addressing some enduring observational problems, such as the dark universe. Additionally, they can be used to advance the results of general relativity in astrophysics. Wormholes, or imagined passageways through spacetime, have the potential to revolutionize interstellar transport and cosmic interconnection. In the present work, the existence and characteristics of wormhole solutions in the context of the non‐linear function of f(Q)$f(\mathcal {Q})$ gravity are investigated. A typical characteristic of maintaining wormholes is the presence of exotic stuff that defines the energy conditions (ECs). The authors looked at the ECs that must be met and analyzed how the f(Q)$f(\mathcal {Q})$ function affects the energy‐momentum requirements for maintaining the wormholes open. For a comprehensive understanding of wormhole geometries, we also studied the embedding diagram and volume integral quantifier. Nowadays, alternative gravity is a crucial tool for addressing some enduring observational problems, such as the dark universe. Additionally, they can be used to advance the results of general relativity in astrophysics. Wormholes, or imagined passageways through spacetime, have the potential to revolutionize interstellar transport and cosmic interconnection. In the present work, the existence and characteristics of wormhole solutions in the context of the non‐linear function of f(Q)$f\!(\mathcal{Q})$ gravity are investigated. A typical characteristic of maintaining wormholes is the presence of exotic stuff that defines the energy conditions (ECs). The authors looked at the ECs that must be met and analyzed how the f(Q)$f\!(\mathcal{Q})$ function affects the energy‐momentum requirements for maintaining the wormholes open. For a comprehensive understanding of wormhole geometries, we also studied the embedding diagram and volume integral quantifier. [ABSTRACT FROM AUTHOR]

Snyder's quantum space‐time which is Lorentz invariant is investigated. It is found that the quanta of space‐time have a positive mass that is interpreted as a positive real mass gap of space‐time. This mass gap is related to the minimal length of measurement which is provided by Snyder's algebra. Several reasons to consider the space‐time quanta as a 24‐cell are discussed. Geometric reasons include its self‐duality property and its 24 vertices that may represent the standard model of elementary particles. The 24‐cell symmetry group is the Weyl/Coxeter group of the F4$F_4$ group which was found recently to generate the gauge group of the standard model. It is found that 24‐cell may provide a geometric interpretation of the mass generation, Avogadro number, color confinement, and the flatness of the observable universe. The phenomenology and consistency with measurements is discussed. Snyder's quantum space‐time which is Lorentz invariant is investigated. It is found that the quanta of space‐time have a positive mass that is interpreted as a positive real mass gap of space‐time. This mass gap is related to the minimal length of measurement which is provided by Snyder's algebra. Several reasons to consider the space‐time quanta as a 24‐cell are discussed. Geometric reasons include its self‐duality property and its 24 vertices that may represent the standard model of elementary particles. The 24‐cell symmetry group is the Weyl/Coxeter group of the F4 group which was found recently to generate the gauge group of the standard model. It is found that 24‐cell may provide a geometric interpretation of the mass generation, Avogadro number, color confinement, and the flatness of the observable universe. The phenomenology and consistency with measurements is discussed. [ABSTRACT FROM AUTHOR]

Herein, we report the direct intramolecular coupling of primary and secondary alcohols for the selective synthesis of macrocyclic olefins in the presence of Ni‐zeolite catalyst under continuous flow. This reaction proceeds via dehydration of secondary alcohols to alkenes, which subsequently undergo intramolecular dehydrative coupling reaction with a primary alcohol to obtain moderate yields of macrocyclic olefins. This reaction is also effective for the coupling of secondary‐secondary alcohols and alkene‐alcohols to produce diverse macrocyclic olefin products. This unique approach has various advantages including step‐economy, no additives and pre‐functionalization required, inexpensive and reusable catalyst, and exemplification with 23 macrocycles in different ring sizes. The continuous flow macrocyclisation afforded higher productivity and space‐time yield than the batch reaction conditions. [ABSTRACT FROM AUTHOR]

We develop a new version of the causal theory of spacetime. Whereas traditional versions of the theory seek to identify spatiotemporal relations with causal relations, the version we develop takes causal relations to be the grounds for spatiotemporal relations. Causation is thus distinct from, and more basic than, spacetime. We argue that this non‐identity theory, suitably developed, avoids the challenges facing the traditional identity theory. [ABSTRACT FROM AUTHOR]

Time‐dependent Maxwell's equations govern electromagnetics. Under certain conditions, we can rewrite these equations into a partial differential equation of second order, which in this case is the vectorial wave equation. For the vectorial wave equation, we examine numerical schemes and their challenges. For this purpose, we consider a space‐time variational setting, that is, time is just another spatial dimension. More specifically, we apply integration by parts in time as well as in space, leading to a space‐time variational formulation with different trial and test spaces. Conforming discretizations of tensor‐product type result in a Galerkin–Petrov finite element method that requires a CFL condition for stability which we study. To overcome the CFL condition, we use a Hilbert‐type transformation that leads to a variational formulation with equal trial and test spaces. Conforming space‐time discretizations result in a new Galerkin–Bubnov finite element method that is unconditionally stable. In numerical examples, we demonstrate the effectiveness of this Galerkin–Bubnov finite element method. Furthermore, we investigate different projections of the right‐hand side and their influence on the convergence rates. This paper is the first step toward a more stable computation and a better understanding of vectorial wave equations in a conforming space‐time approach. [ABSTRACT FROM AUTHOR]

Aims: In Canada, enteric diseases pose substantial health and economic burdens. The distribution of these diseases is uneven across both geography and time and understanding these patterns is therefore important for the prevention of future outbreaks. We evaluated temporal, spatial and space–time clustering of laboratory‐confirmed cases of Campylobacter spp. (n = 28,728), non‐typhoidal Salmonella spp. (n = 22,640), Shiga toxin‐producing Escherichia coli (STEC; n = 1340), Yersinia spp. (n = 1674) and Listeria monocytogenes (n = 471) infections, reported between 2010 and 2017 inclusive in Ontario, the most populous province in Canada (population ~ 13,500,000 in 2016). Methods and Results: For each enteric pathogen, we calculated the mean incidence rates (IRs) for Ontario's 35 public health unit (PHU) areas and visualized them using choropleth maps. We identified temporal, spatial and space–time high infection rate clusters using retrospective Poisson scan statistics. Campylobacter and Salmonella infections had the highest IRs, while Listeria infections had the lowest. Campylobacter, Salmonella, STEC and Listeria mostly clustered temporally in the spring/summer and sometimes extended into fall, while Yersinia showed a less clear seasonal pattern. The IR visualizations and spatial and space–time scan statistics showed geographic heterogeneity of infection rates with high infection rate clusters detected mainly in PHUs across the southwestern and central‐western regions of Ontario for Campylobacter, Salmonella and STEC infections, and mainly in PHUs located in the central‐eastern regions for Yersinia and Listeria. A high proportion of cases in some of the significant Salmonella, STEC and Listeria infection clusters were linked to disease outbreaks. Conclusions: Results from this study will inform heightened public health surveillance, and prevention and control programmes, in populations and regions of high infection rates. Further research is needed to determine the pathogen‐specific socioeconomic, environmental and agricultural risk factors that may be related to the temporal and spatial disease patterns we observed in our study. [ABSTRACT FROM AUTHOR]

Space‐time adaptive processing (STAP) array has found extensive use in the global navigation satellite system for interference suppression. Nevertheless, the conventional space‐time array necessitates multiple antennas and time delay taps, resulting in a heavy burden on both hardware and computation resources. Thus, lowering the cost and complexity of STAP becomes a considerable problem demanding prompt solutions. This work designs a space‐time array reconfiguration scheme based on the joint selection strategy of the antenna and delay tap to address this problem. The reconstructed array can induce a high signal to interference plus noise power ratio (SINR) when using fewer antennas and delay taps. The space‐time correlation coefficient (STCC) is first presented to manifest the influence of reconfiguration on output SINR. Then, we formulate the space‐time array reconfiguration mathematical model, aiming to minimise STCC. Two reconfiguration methods are provided to solve the optimal array configuration of antennas and delay taps that can reach the minimum STCC and maximum SINR. The optimal antenna‐delay tap pairs are finally selected to comprise the reconstructed array. Substantial simulation experiments verify that the presented scheme and strategy are effective and reliable in space‐time array reconfiguration. [ABSTRACT FROM AUTHOR]

The practice of space-for-time substitution assumes that the responses of species or communities to land-use change over space represents how they will respond to that same change over time. Space-for-time substitution is commonly used in both ecology and conservation, but whether the assumption produces reliable insights remains inconclusive. Here, we tested space-for-time substitution using data from the North American Breeding Bird Survey (BBS) and Global Forest Change (GFC) to compare the effects of landscape-scale forest cover on bird richness and abundance over time and space, for 25 space-time comparisons. Each comparison consisted of a landscape that experienced at least 20% forest loss over 19 years (temporal site) and a set of 15-19 landscapes (spatial sites) that represented the same forest cover gradient over space in 2019 as experienced over time in their corresponding temporal site. Across the 25 comparisons, the observed responses of forest and open-habitat birds to forest cover over time generally aligned with their responses to forest cover over space, but with comparatively higher variability in the magnitude and direction of effect across the 25 temporal slopes than across the 25 spatial slopes. On average, the mean differences between the spatial and temporal slopes across the 25 space-time comparisons frequently overlapped with zero, suggesting that the spatial slopes are generally informative of the temporal slopes. However, we observed high variability around these mean differences, indicating that a single spatial slope is not strongly predictive of its corresponding temporal slope. We suggest that our results may be explained by annual variability in other relevant environmental factors that combine to produce complex effects on population abundances over time that are not easily captured by snapshots in space. While not being a 1:1 proxy, measuring bird responses to changes in habitat amount in space provides an idea on how birds might be expected to eventually equilibrate to similar changes in habitat amount over time. Further, analyses such as this could be potentially used to screen for cases of regional space-time mismatches where population-limiting factors other than habitat could be playing a more important role in the population trends observed there. [ABSTRACT FROM AUTHOR]

The article delves into the multifaceted career of architect and artist Lebbeus Woods, highlighting his early influences and creative processes. Topics include his exploration of architectural discourse, his affinity for transience and fluidity, and his innovative approaches to representation and experimentation with various media.

The Madden–Julian Oscillation (MJO) displays an evident seasonality in its spatiotemporal scale selection. In boreal winter, the MJO is best behaved at wavenumber 2 and oscillates on a narrow time scale centering on a ∼55‐day period. In contrast, a wavenumber‐1 selection and a broad oscillation frequency centering on a ∼33‐day period are observed in boreal summer. Using the space‐time cross‐spectral analysis between convection and moisture budget, we reveal that column processes determine seasonal variations in the MJO spatial organization, while the MJO is strongly damped by the horizontal moisture advection mainly due to its meridional component (Vadv). A timescale decomposition analysis suggests that the damping effect of Vadv results primarily from high‐frequency synoptic‐scale disturbances, and the Vadv component related to the seasonal‐mean moisture generally supports the MJO growth at large wavenumbers while inhibits the growth of small wavenumbers, which is the most evident in boreal summer. The advection of seasonal‐mean moisture by anomalous zonal winds supports the MJO growth at all wavenumbers in boreal winter, but in boreal summer the growth becomes weak and even turns negative for small wavenumbers. Furthermore, different MJO timescale selections in winter versus summer are rooted in the Vadv, as both the column processes and zonal moisture advection mainly support the propagation of high‐frequency modes. Observational results related to the horizontal seasonal‐mean moisture advection are reasonably validated in a dynamical moisture model. These findings advance our understanding of the MJO seasonality and offer alternative diagnoses for evaluating the MJO simulation fidelity in contemporary climate models. Plain Language Summary: The Madden–Julian Oscillation (MJO) is an intraseasonal (20–100‐day) wave phenomenon prevailing in the tropics. Herein, we reveal that in boreal winter, the MJO prefers to organize at wavenumber 2 and oscillate regularly with a roughly 55‐day period. In boreal summer, the MJO is typically a wavenumber‐1 wave but can oscillate with broad frequencies centering on a shorter time scale (∼33‐day period). We explain these features through the convection‐humidity cross‐spectrum analysis. The results suggest that the upward transport process of basic‐state humidity largely shapes the seasonality in the spatial‐scale selection, while the seasonal variations of the oscillation frequency are mainly caused by the meridional‐wind advection of basic‐state humidity. Moreover, we find that the meridional advection can support the MJO growth of small wavelength modes, while the zonal advection can destabilize all wavenumbers in boreal winter but damps small wavenumbers in boreal summer. We also partly reproduce these observed features in a mathematical model and validate the crucial importance of horizontal moisture advection in shaping the MJO seasonality. Our results help understand MJO simulations in state‐of‐the‐art climate models. Especially, we propose that the moisture‐convection coupling processes can be used to attribute the possible modeling biases, if any. Key Points: The MJO shows an evident seasonality in the spatiotemporal scale selectionConvection‐coherent moisture processes well explain the MJO seasonality of space‐time spectral featuresA dynamical moisture model partly validates the observed MJO scale seasonality [ABSTRACT FROM AUTHOR]

We investigate the critical exponent of non‐global solutions to the following inhomogeneous pseudo‐parabolic equation with a space‐time forcing term: ut−kΔut=Δu+|u|p+tσω(x)forx∈ℝn,t>0,u(x,0)=u0(x)forx∈ℝn,$$ \left\{\begin{array}{lll}{u}_t-k\Delta {u}_t=\Delta u+{\left|u\right|}^p+{t}^{\sigma}\omega (x)\kern0.30em & & \mathrm{for}\kern0.30em x\in {\mathrm{\mathbb{R}}}^n,t>0,\\ {}u\left(x,0\right)={u}_0(x)& & \mathrm{for}\kern0.30em x\in {\mathrm{\mathbb{R}}}^n,\end{array}\right. $$where n≥1$$ n\ge 1 $$ is an integer; k>0$$ k>0 $$, p>1$$ p>1 $$, and σ>−1$$ \sigma >-1 $$ are three constants; and u0,ω∈C0(ℝn)$$ {u}_0,\omega \in {C}_0\left({\mathrm{\mathbb{R}}}^n\right) $$. By obtaining a priori estimate for the solutions and the contradiction argument, we show that there exists a critical exponent: pc(σ):=2σ−12σ+1,ifn=1andσ∈−1,−12,∞,ifn=1andσ∈−12,∞,1−1σ,ifn=2andσ∈(−1,0),∞,ifn=2andσ∈[0,∞),2σ−n2σ−n+2,ifn>2andσ∈(−1,0],∞,ifn>2andσ∈(0,∞),$$ {p}_c\left(\sigma \right):= \left\{\begin{array}{rcl}& \frac{2\sigma -1}{2\sigma +1},& \mathrm{if}\kern0.30em n=1\kern0.30em \mathrm{and}\kern0.30em \sigma \in \left(-1,-\frac{1}{2}\right),\\ {}& \infty, & \mathrm{if}\kern0.30em n=1\kern0.30em \mathrm{and}\kern0.30em \sigma \in \left[-\frac{1}{2},\infty \right),\\ {}& 1-\frac{1}{\sigma },& \mathrm{if}\kern0.30em n=2\kern0.30em \mathrm{and}\kern0.30em \sigma \in \left(-1,0\right),\\ {}& \infty, & \mathrm{if}\kern0.30em n=2\kern0.30em \mathrm{and}\kern0.30em \sigma \in \left[0,\infty \right),\\ {}& \frac{2\sigma -n}{2\sigma -n+2},& \mathrm{if}\kern0.30em n>2\kern0.30em \mathrm{and}\kern0.30em \sigma \in \left(-1,0\right],\\ {}& \infty, & \mathrm{if}\kern0.30em n>2\kern0.30em \mathrm{and}\kern0.30em \sigma \in \left(0,\infty \right),\end{array}\right. $$such that the problem does not admit any global solutions when p0$$ {\int}_{{\mathrm{\mathbb{R}}}^n}\omega (x) dx>0 $$. Our obtained results show that the forcing term induces an interesting phenomenon of continuity/discontinuity of the critical exponent pc(σ)$$ {p}_c\left(\sigma \right) $$ depending on the dimension n$$ n $$. Namely, we found that when n=1$$ n=1 $$, limσ→−12−pc(σ)=limσ→−12+pc(σ)=∞$$ \underset{\sigma \to -{\frac{1}{2}}^{-}}{\lim }{p}_c\left(\sigma \right)=\underset{\sigma \to -{\frac{1}{2}}^{+}}{\lim }{p}_c\left(\sigma \right)=\infty $$; when n=2$$ n=2 $$limσ→0−pc(σ)=limσ→0+pc(σ)=∞$$ \underset{\sigma \to {0}^{-}}{\lim }{p}_c\left(\sigma \right)=\underset{\sigma \to {0}^{+}}{\lim }{p}_c\left(\sigma \right)=\infty $$; and when n≥3$$ n\ge 3 $$limσ→0−pc(σ)=nn−2<∞$$ \underset{\sigma \to {0}^{-}}{\lim }{p}_c\left(\sigma \right)=\frac{n}{n-2}<\infty $$, limσ→0+pc(σ)=∞$$ \underset{\sigma \to {0}^{+}}{\lim }{p}_c\left(\sigma \right)=\infty $$. Furthermore, limσ→κ−pc(σ)$$ \underset{\sigma \to {\kappa}^{-}}{\lim }{p}_c\left(\sigma \right) $$ with κ=−12$$ \kappa =-\frac{1}{2} $$ when n=1$$ n=1 $$ and κ=0$$ \kappa =0 $$ when n≥2$$ n\ge 2 $$ coincides with the critical exponent of the above problem with σ=0$$ \sigma =0 $$. [ABSTRACT FROM AUTHOR]

We study the embedding of octonions in the Clifford geometric algebra for space‐time STA Cl(1,3)$$ Cl\left(1,3\right) $$, as suggested by Anthony Lasenby at AGACSE 2021. As far as possible, we extend the approach to similar octonion embeddings for all three‐ and four‐dimensional Clifford geometric algebras Cl(p,q)$$ Cl\left(p,q\right) $$, n=p+q=3,4$$ n=p+q=3,4 $$. Noticeably, the lack of a quaternionic subalgebra in Cl(2,1)$$ Cl\left(2,1\right) $$ seems to prevent the construction of an octonion embedding in this case and necessitates a special approach in Cl(2,2)$$ Cl\left(2,2\right) $$. As examples, we present for Cl(3,0)$$ Cl\left(3,0\right) $$ the nonassociativity of the octonionic product in terms of multivector grade parts with cyclic symmetry and show how octonion products and involutions can be combined to make the opposite transition from octonions to the Clifford geometric algebra Cl(3,0)$$ Cl\left(3,0\right) $$ and how octonionic multiplication can be represented with (complex) biquaternions or Pauli matrix algebra. [ABSTRACT FROM AUTHOR]

Summary: Two fundamental aspects of wireless communication, which make it challenging and interesting, are fading and interference. Multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) techniques when utilized together effectively combat fading and interference thereby achieving the requirement of high data rate and high performance. In this paper, a 2 × 1 MIMO‐OFDM baseband model of the physical layer according to IEEE 802.16.1 standard employing 256 subcarriers capable of transmitting 192 Mbps in a 21‐MHz bandwidth frequency selective fading channel is designed. All essential blocks of the communication system like channel coding, modulation, time synchronization, frequency synchronization, channel estimation, residual carrier frequency offset (CFO) estimation, and channel decoding are covered at the algorithm level. A two‐step time synchronization method is used in this work to avoid any ambiguity in frame detection. A long preamble, consisting of three short preambles, is designed to aid in time synchronization, frequency synchronization, and channel estimation. To evaluate the performance of the proposed design, simulations were carried out in MATLAB‐SIMULINK. [ABSTRACT FROM AUTHOR]

We present a reduced order model for efficient nonlinear homogenization of bones, accounting for strength difference effects and containing some well‐known plasticity models (like von Mises or Drucker‐Prager) as special cases. The reduced order homogenization is done by using a cluster‐based model order reduction technique, called cluster‐based nonuniform transformation field analysis. For an offline phase, a space–time decomposition is performed on the mesoscopic plastic strain fields, while a clustering analysis is employed for a spatial decomposition of the mesoscale RVE model. A volumetric‐deviatoric split is additionally introduced to capture the enriched characteristics of the mesoscopic plastic strain fields. For an online analysis, the reduced order model is formulated in a unified minimization problem, which is compatible with a large variety of material models. Both cortical and trabecular bones are considered for numerical experiments. Compared to conventional FE‐based RVE computations, the developed reduced order model renders a considerable acceleration rate beyond 103, while maintaining a sufficient accuracy level. [ABSTRACT FROM AUTHOR]

We assess a possibility to efficiently represent the strongly coupled increment in an ocean–atmosphere coupled data assimilation (DA) system by applying an iterative procedure involving uncoupled solvers and the weakly coupled analysis as a first guess approximation to the strongly coupled increment. Using the output of the ensemble‐based weakly coupled DA system, we explore convergence of the approximations to the strongly coupled DA solution by applying the uncoupled solver to a sequence of innovation vectors at various spacetime locations over the global ocean grid. The results demonstrate that, in general, fewer than two iterations are required to approximate the coupled increment in the majority of the locations tested with sufficient (3%) accuracy given the uncertainty of the background error covariance estimated from the limited number of the ensemble members. We assess the impact of data thinning and hybridization of the background error covariance model on the convergence of the iterative approximations to the strongly coupled increment. An empirical relationship between the spectral radius of the expansion matrix and convergence rate is obtained. [ABSTRACT FROM AUTHOR]

We construct a space‐time parallel method for solving parabolic partial differential equations by coupling the parareal algorithm in time with overlapping domain decomposition in space. The goal is to obtain a discretization consisting of "local" problems that can be solved on parallel computers efficiently. However, this introduces significant sources of error that must be evaluated. Reformulating the original parareal algorithm as a variational method and implementing a finite element discretization in space enables an adjoint‐based a posteriori error analysis to be performed. Through an appropriate choice of adjoint problems and residuals the error analysis distinguishes between errors arising due to the temporal and spatial discretizations, as well as between the errors arising due to incomplete parareal iterations and incomplete iterations of the domain decomposition solver. We first develop an error analysis for the parareal method applied to parabolic partial differential equations, and then refine this analysis to the case where the associated spatial problems are solved using overlapping domain decomposition. These constitute our time parallel algorithm and space‐time parallel algorithm respectively. Numerical experiments demonstrate the accuracy of the estimator for both algorithms and the iterations between distinct components of the error. [ABSTRACT FROM AUTHOR]

This research article aims to get superabundant wave solutions of the fractional nonlinear space–time telegraph via two computational schemes (modified Khater (MK) method and simplest equation (SE) method) through a new fractional operator (Atangana–Baleanu [AB] fractional derivative). These solutions are used to calculate the boundary and initial conditions that allow applying the B‐spline collection schemes for constructing the numerical solutions and absolute value of error between obtained exact and numerical solutions. On the other hand, the second goal of this research is to investigate the accuracy of used computational schemes and their constructed solutions, where the investigated model is one of the most attractive models for studying in the electrified transmission or electromagnetic waves. This model, which is used to illustrate as the electromagnetic waves do keep mirrored about the wire, or that suspense patterns perform exhibit along the line, describes the cutting‐edge or voltage of an electrified transmission range with the day yet distance. Oliver Heaviside formulated this model in 1880. [ABSTRACT FROM AUTHOR]

Quantifying home‐range size and habitat resource selection are important elements in wildlife ecology and are useful for informing conservation action. Many home‐range estimators and resource selection functions are currently in use. However, both methods are fraught with analytical issues inherent within autocorrelated movement data from irregular sampling and interpretation of resource selection model parameters to inform conservation management. Here, we apply satellite remote sensing technologies to provide updated estimates of home‐range size and first estimates of fine‐scale resource selection for six adult Philippine Eagles Pithecophaga jefferyi using a space–time autocorrelated kernel density estimate (AKDE) home‐range estimator and non‐parametric resource selection functions. All six adult Eagles showed distinct site fidelity, with continuous range residency between 2 and 18 km, 1 month after tagging. The space–time AKDE home‐range estimators had a median 95% home‐range size = 68 km2 (95% confidence interval (95% CI) 62–74 km2, range: 39–161 km2), with the median 50% core range size = 13 km2 (95% CI 11–14 km2, range 9–33 km2). From the resource selection functions, all adult Philippine Eagles used habitat high in photosynthetic leaf and canopy structure but avoided areas of old‐growth biomass and denser areas of vegetation. This is possibly due to foraging forays into secondary forest and fragmented agricultural areas away from nesting sites. For the first time, we determine two important fine‐scale spatial processes for this Critically Endangered raptor that can help in directing conservation management. Rather than employing traditional home‐range estimators and resource selection functions, we recommend that analysts consider space–time approaches and non‐parametric resource selection functions to animal movement data to explore fully space–time and resource selection. [ABSTRACT FROM AUTHOR]

Non‐perennial streams have a global prevalence, but quantitative knowledge of the temporal dynamics of their flowing length—namely the extent of the wet portion of the stream network—remains limited, as the monitoring of the spatiotemporal configuration of wet channels is challenging in most settings. This work combines the high spatial resolution of visual surveys and the high temporal resolution of camera‐based approaches to reconstruct the space‐time stream network dynamics in a 3.7 km2 Mediterranean catchment of central Italy. Information on the hydrological status of the stream network derived from 40 field surveys and sub‐hourly images collected with 21 stage‐cameras are combined exploiting the hierarchical principle. The latter postulates the existence of a Bayesian chain, defined from the local persistence of the nodes that dictates their wetting/drying order during expansion/retraction cycles of the flowing stream network. Our results highlight the complexity of network dynamics in the study area: while the number of wet nodes decreases during the dry season and increases during the wet season, the local persistency exhibits a highly heterogeneous non‐monotonic spatial pattern, originating a dynamically disconnected network. Despite this heterogeneity, the hierarchical model well approximates the temporal evolution of the state of the network nodes, with an accuracy that exceeds 99%. Crucially, the model allows the reconstruction of the wet portion even in cases in which part of the network was not observed. This work provides a novel conceptual approach for the reconstruction of the wet portion of the network in poorly accessible sites. Key Points: Field data on the hydrological status of the drainage network are collected via heterogeneous spatiotemporal resolution techniquesData are combined to reconstruct the long‐term active drainage network dynamics exploiting the hierarchical principleThe model reproduces the complexity of the non‐monotonic pattern of the wet portion of the network in the study site [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new velocity‐based space‐time finite element method for computing the large deformation of solids over arbitrary Lagrange/Eulerian moving meshes. The proposed method is oriented toward quasi‐static deformation problems with hypoelastic and neo‐Hookean hyperelastic constitutive models. The Cauchy stress in the weak form of the linear momentum equation is explicitly described in terms of deformation velocity through consistent time integration of objective stress rates transferred in the arbitrary moving mesh. Consequently, the resultant system equation only contains the space‐time nodal velocity as the primary unknown. An iterative algorithm for solving the discretized system equation is implemented, whereby the nonlinearities induced by geometrical change in the computational domain as well as nonlinear constitutive equations are computed in an iterative manner updating the stress and the strain over the moving mesh of the deforming domain. Three benchmark problems, such as uniform beam compression, thick‐cylinder compression with superimposed rigid body rotation and extrusion of a column involving material loss, have been solved in order to examine the accuracy of the proposed numerical scheme. The numerical results have revealed the proper computation of the stress and the displacement of the solids undergoing the large deformation and rotation over the arbitrary Lagrange/Eulerian moving meshes, and have shown the validity and applicability of the proposed method with linear convergence of the iterative algorithm. [ABSTRACT FROM AUTHOR]

Floods in ideal landscapes follow a coherent pattern where single water‐covered areas expand and afterward recede following the inverse sequence, but deviate in real landscapes due to natural or human factors resulting in water coverage shifts. Using remote sensing, we introduced two indices to describe the discrepancies between spatially integrated versus pixel‐level frequency distributions under maximum inundated conditions (dext) and throughout all flooding conditions (dtot), expressed as the relative weight of shifts on each landscape's maximum registered coverage, theoretically ranging between no displacement (<20%) to maximum displacement (≪inf). Globally, over 36 years inundations exhibited redistributions representing, on average, 25% and 45% of their peak extents revealing previously unnoticed extra engaged areas and rotational movements within events, rising up to 500% in meandering rivers (South America) and irrigated croplands (Central Asia). We also assessed the influence of natural and human variables and discussed the indices' potential for advancing flood research. Plain Language Summary: While in ideal landscapes surface water should display the same spatial distribution across the expansion and recession stages of any flooding event, real dynamics may drift away from this expected pattern. We developed two indices based on remote sensing data to locate where these shifts are important and understand how they are influenced by nature and humans. By analyzing data from around the world, we discovered that thanks to the displacement from the ideal distributions, surface water covered globally an extra quarter of the area. Natural factors like low terrain ruggedness and high aridity foster much larger inundation displacement. In regions hosting rivers that carry large quantities of sediment and often change their course (e.g., India and Perú), displacement engages five times more area in floods than expected. We also found that water infrastructure like reservoirs and irrigation also influenced inundation displacement. For instance, displacement was very relevant in intensely irrigated regions like Central Asia and Australia, reflecting surface water deviation as needed for crop production. Because these variations scope water's spatiotemporal dynamics with important implications for the provision of many ecosystem services, their quantification and assessment allow us to monitor and understand our ongoing imprint on regional inundation dynamics. Key Points: We developed two complementary indices to describe water cover shifts between and within flooding eventsOver the last 36 years, shifts expanded the global flooded‐affected area by 25% with another 20% redistributing at intermediate stagesFlat topographies, arid climates, and irrigation favor this phenomenon while river dams and channels inhibit it over time [ABSTRACT FROM AUTHOR]

In the context of simulation‐based methods, multiple challenges arise, two of which are considered in this work. As a first challenge, problems including time‐dependent phenomena with complex domain deformations, potentially even with changes in the domain topology, need to be tackled appropriately. The second challenge arises when computational resources and the time for evaluating the model become critical in so‐called many query scenarios for parametric problems. For example, these problems occur in optimization, uncertainty quantification (UQ), or automatic control, and using highly resolved full‐order models (FOMs) may become impractical. To address both types of complexity, we present a novel projection‐based model order reduction (MOR) approach for deforming domain problems that takes advantage of the time‐continuous space‐time formulation. We apply it to two examples that are relevant to engineering or biomedical applications and conduct an error and performance analysis. In both cases, we are able to drastically reduce the computational expense for a model evaluation and, at the same time, maintain an adequate accuracy level, each compared to the original time‐continuous space‐time full‐order model (FOM). All in all, this work indicates the effectiveness of the presented MOR approach for deforming domain problems by taking advantage of a time‐continuous space‐time setting. [ABSTRACT FROM AUTHOR]

The demand for high‐resolution videos has been consistently rising across various domains, propelled by continuous advancements in societal. Nonetheless, limitations in imaging and economic factors often result in obtaining low‐resolution images. The currently available space‐time video super‐resolution methods often fail to fully exploit the information existing within the spatio‐temporal domain. To address this problem, the issue is tackled by conceptualizing the input low‐resolution video as a cuboid structure. An innovative methodology called "Cuboid‐Net", which incorporates a multi‐branch convolutional neural network, is introduced. Cuboid‐Net is designed to collectively enhance the spatial and temporal resolutions of videos, enabling the extraction of rich and meaningful information across both spatial and temporal dimensions. Specifically, the input video is taken as a cuboid to generate different directional slices as input for different branches of the network. The proposed network contains four modules, that is, a multi‐branch‐based hybrid feature extraction module, a multi‐branch‐based reconstruction module, a first‐stage quality enhancement module, and a second‐stage cross frame quality enhancement module for interpolated frames only. Experimental results demonstrate that the proposed method is not only effective for spatial and temporal super‐resolution of video but also for spatial and angular super‐resolution of light field. [ABSTRACT FROM AUTHOR]

This paper argues that all of the standard theories about the divisions of space and time can benefit from, and may need to rely on, parsimony considerations. More specifically, whether spacetime is discrete, gunky or pointy, there are wildly unparsimonious rivals to standard accounts that need to be resisted by proponents of those accounts, and only parsimony considerations offer a natural way of doing that resisting. Furthermore, quantitative parsimony considerations appear to be needed in many of these cases. [ABSTRACT FROM AUTHOR]

To establish a more sustainable future, Saudi Arabia is striving to reduce its dependency on fossil fuels and promote renewable energies. Solar energy is a major resource in Saudi Arabia because of the country's geographical location with year‐round clear skies and plentiful sunlight. However, although solar energy is a clean and safe renewable energy resource, it can be quite unpredictable. Therefore, solar irradiance needs to be forecasted and simulated as accurately as possible on both regional and national scales in the Kingdom to assist in planning for reserve usage, switching sources and short‐term power purchases. Based on an hourly solar diffuse horizontal irradiance (DHI) dataset from 45 different Saudi Arabian solar monitoring stations, this study proposes a novel spatio‐temporal model. We identify the temporal dependency of DHI as cyclostationary and incorporate this key observation in the model. This feature helps yield accurate (i.e. significantly close to the ground truth and with narrow confidence bands) probabilistic forecasts and realistic simulations in near‐future time points and at new locations. Then, the proposed model is compared with a stationary model that fails to recognize the cyclostationarity structure in the data. The proposed model produces significantly better predictions and simulations than the stationary model. Further, we calculate the photovoltaic power outputs using the simulated samples from both the models and the original observations and then compare them. The simulated samples from the proposed model afford photovoltaic power output estimates that are significantly closer to the original observed data than those from the stationary model, and therefore, they can better assist photovoltaic power output operators in assessing solar energy production and operational pre‐planning to mitigate impacts by the uncertain nature of solar irradiance. [ABSTRACT FROM AUTHOR]

This article analyzes the role of emotion in narrations about the past, understandable as familial, intergenerational, or national. I examine how participants report and display affect in narratives about Aristides de Sousa Mendes, the Portuguese consul of Bordeaux who issued thousands of lifesaving visas in June of 1940. Three sets of participants (descendants of visa recipients, Sousa Mendes' descendants, and Portuguese institutional representatives) each explicitly report and implicitly display how the Sousa Mendes story moves them emotionally. I then discuss how the emotion in these narratives may be circulated and taken up by broader audiences. Building on Irvine's discussion of the heteroglossia of affective expression (1990), participants may attribute emotion to others, signal emotion as occurring in the present or in a prior space–time, or merge emotional past and present in various types of emotional "reliving." By treating emotion as eventlike, it can thus be considered chronotopic. I analyze the relationships between (re)presentation of emotion across multiple narrated and narrating chronotopes. This approach reveals how differently positioned participants' cross‐chronotope alignments yield particular types of affective displays and experiences that others can then take up and recontextualize. [ABSTRACT FROM AUTHOR]

Accurate spatiotemporal estimation of non‐methane volatile organic compounds (NMVOCs) plays a pivotal role in establishing sophisticated early warning systems and formulating strategies to combat air pollution. Despite these critical applications, robust estimation of high spatiotemporal resolution NMVOCs concentrations remains a challenge. In this study, we develop a space‐time Light Gradient Boosting Machine (STLGB) model, which successfully renders hourly maps of NMVOCs concentrations across Shanghai from 2019 to 2022 by integrating spatiotemporal information. After extensive training, the STLGB model demonstrates remarkable estimation performance for NMVOCs, accounting for multiple spatiotemporal variables (R2 = 0.92, RMSE = 34.52 ppb). With the developed model, we provide first high‐resolution (1 km) hourly NMVOCs concentration maps, uncovering previously overlooked spatiotemporal variations. Further, SHapley Additive exPlanation (SHAP) regression values reveal significant local interpretation capabilities of the STLGB model, emphasizing the strong influence of emissions on NMVOCs estimation, whilst acknowledging the important contribution of space and time term. Our study of the pandemic lockdown further showcases the model's adaptability to unique events influenced by policy changes. The superior performance of the STLGB model, with its minimal computational memory requirements and faster speed, makes it an ideal tool for air pollutant estimation, adaptable to any region with NMVOCs monitoring capabilities. Plain Language Summary: Non‐methane Volatile organic compounds (NMVOCs) are significant air pollutants that have severe effects on health and the environment. Despite the availability of VOCs monitoring stations that can provide data with good temporal resolution, the low spatial resolution of these stations remains a challenge. Accurate estimation of NMVOCs concentrations requires new methods to address these spatial resolution issues. In recent years, machine learning‐based models have emerged as a promising alternative for air pollution estimations. However, research on high‐resolution mapping of NMVOCs concentrations using machine learning models is limited. This study provides the first predicted spatial distribution of hourly NMVOCs map deduced from sparse observations using the machine learning models. We developed a space‐time LightGBM model to estimate NMVOCs concentrations at 1 km spatial and hourly temporal resolution in Shanghai. Meanwhile, we use the shapely additive explanations to quantify and visualize the complex relationships between the input variables in the model. Moreover, we also offers an alternative solution to air pollution modeling with regard to unusual events (such as the COVID‐19 lockdown). Key Points: A space‐time LightGBM (STLGB) model in machine learning is used to estimate NMVOCs reliablyHourly NMVOCs maps were produced at 1 km resolution by the STLGB modelThe STLGB model shows good performance with cross‐validation R2 of 0.92 [ABSTRACT FROM AUTHOR]

In this paper, the standard and the localized space‐time radial basis function (RBF) collocation methods are modified and combined with the time‐marching scheme and space‐time domain decomposition technique for simulating the long‐time transient heat conduction in 3D anisotropic composite materials. In the proposed approaches, we set the source points outside the whole space‐time domain in the standard space‐time RBF collocation method or outside the established subdomain in the localized approach by introducing the space and time magnification factors, instead of distributing them inside the original domain. In addition, the space‐time regulating factor is defined and added to the conventional schemes to improve the stability of numerical methods. The modified approaches are resulted in a simple and effective time‐marching process which can achieve long‐time simulation, resting on the property that the coefficient matrices generated by these two methods are only related to the space‐time distance between the collocation points and source points. Our ultimate aim is to develop a computing system for resolving dynamic problems in composite materials by designing a space‐time domain decomposition technique. Numerical experiments are conducted to demonstrate the accuracy, efficiency and stability of the presented methodologies. [ABSTRACT FROM AUTHOR]

In the K‐essence Vaidya Schwarzschild spacetime, the dynamical horizon equation to measure the mass‐loss due to Hawking radiation and the tunneling formalism (Hamilton‐Jacobi method) to calculate the hawking temperature is applied. Assuming the Dirac‐Born‐Infeld kind of non‐standard action for the K‐essence here, the background physical spacetime is a static spherically symmetric black hole, and the K‐essence scalar field to be a function only of either forward or backward time is constrained. The K‐essence emergent gravity and the generalizations of Vaidya spacetime have been linked by Manna et al. In this paper, Sawayama's modified description of the dynamical horizon to show that the obtained findings deviate from the standard Vaidya spacetime geometry are used. [ABSTRACT FROM AUTHOR]

A set of exact spherically symmetric solutions for describing the interior of a relativistic star in the context of f(R,T)$f(\mathcal {R}, T)$ modified theory of gravity is presented. The existence of a Conformal Killing Vectors (CKV) and Bardeen's model to find the boundary conditions as an exterior space‐time geometry to achieve the metric potentials for current study is used. Moreover, matching conditions have been employed to obtain a set of free parameters for the physical analysis. Furthermore, some physically valid attributes like the behavior of energy density, pressure, equilibrium conditions, the adiabatic index, mass‐radius relation, surface red‐shifts, and compactness factor for the realistic stars such as PSRJ1614−2230$PSR\nobreakspace J1614-2230$, PSRJ1903+327$PSR\nobreakspace J1903+327$, SMCX−1$SMC\nobreakspace X-1$, CenX−3$Cen\nobreakspace X-3$, LMCX−4$LMC\nobreakspace X-4$ and EXO1785−248$EXO\nobreakspace 1785-248$ are investigated. It is observed that for the current investigation, the derived compact star solutions are physically acceptable and authentic in the presence of charge with conformal motion. A set of exact spherically symmetric solutions for describing the interior of a relativistic star in the context of f(R,T)$f(\mathcal {R}, T)$ modified theory of gravity is presented. The existence of a Conformal Killing Vectors (CKV) and Bardeen's model to find the boundary conditions as an exterior space‐time geometry to achieve the metric potentials for current study is used. Moreover, matching conditions have been employed to obtain a set of free parameters for the physical analysis. Furthermore, some physically valid attributes like the behavior of energy density, pressure, equilibrium conditions, the adiabatic index, mass‐radius relation, surface red‐shifts, and compactness factor for the realistic stars such as PSRJ1614−2230$\textit{PSR}\nobreakspace J1614- 2230$, PSRJ1903+327$\textit{PSR}\nobreakspace J1903+327$, SMCX−1$\textit{SMC}\nobreakspace X-1$, CenX−3$\textit{Cen}\nobreakspace X-3$, LMCX−4$\textit{LMC}\nobreakspace X-4$ and EXO1785−248$\textit{EXO}\nobreakspace 1785- 248$ are investigated. It is observed that for the current investigation, the derived compact star solutions are physically acceptable and authentic in the presence of charge with conformal motion. [ABSTRACT FROM AUTHOR]

In this study, we investigated the construction of science learning opportunities focusing on space−time relationships. Guided by ethnography in education, we followed the everyday life of a classroom over their three first years at elementary school. Based on macroanalysis, we examined discursive interactions in temporally distant events and how participants built relationships between these events. Verbal tense, agents in narratives, and relations between texts/contexts guided microanalyses. Results indicate that teacher and students evoked space−time relationships that become an epistemic tool for this class. These relationships structured narratives which the actor in scientific inquiry was the class as a group. Moreover, space−time connections provided articulations between the conceptual, epistemic, and social domains of scientific knowledge in science lessons over time. We discuss methodological contributions of the study, in addition to implications for positioning students as epistemic agents in science learning. [ABSTRACT FROM AUTHOR]

The Hutchinson method can be used to estimate the trace of a function of a matrix A, that is, tr(f(A))$\mathrm{tr}(f(A))$, stochastically. With the variance of the Hutchinson estimator decreasing as O(1/N)$\mathcal {O}(1/\sqrt {N})$, techniques to reduce the variance of this estimator become necessary due to the high accuracy required by some calculations in scientific computing. In lattice QCD, where A is the Dirac operator D stemming from a discretization of the Dirac equation, the accuracy of some calculations involving tr(f(A))$\mathrm{tr}(f(A))$ renders them practically unfeasible if one uses the Hutchinson estimator to approximate the trace. One such variance reduction technique, known as multigrid multilevel Monte Carlo, has been introduced recently to deal with tr(D−1)$\mathrm{tr}(D^{-1})$ for the Laplace 2D, Gauge Laplacian, and Schwinger problems. We use it here in the context of lattice QCD, and moreover, we analyze its impact when dealing with tr(D−1P∼H)$\mathrm{tr}(D^{-1} \widetilde{P}^{H})$, where P∼$\widetilde{P}$ is the matrix that emerges when a displacement in one of the four spacetime dimensions of the lattice is introduced. This latter trace is of importance when computing generalized parton distributions in lattice QCD. [ABSTRACT FROM AUTHOR]

In this work, the finite‐difference time‐domain (FDTD) method is employed to study electromagnetic problems with moving bodies in a moving system. The proposed approach consists in modeling objects with time‐varying positions and using the direct discretization of Maxwell's equations in space and time domains. Doppler effects are investigated for problems with moving observer, source, or reflector, in a moving frame. A distinction is also made between a high‐impedance or low‐impedance plane wave source in motion. The full‐wave electromagnetic simulations are compared with closed‐form equations that agree with wave theory. The proposed analysis shows that, for Doppler radars used every day, the motion of the Earth relative to the Cosmic Microwave Background has a negligible effect and only relative motions in the Earth frame are relevant. [ABSTRACT FROM AUTHOR]

Summary: We present a unified framework to efficiently approximate solutions to fractional diffusion problems of stationary and parabolic type. After discretization, we can take the point of view that the solution is obtained by a matrix‐vector product of the form fτ(L)b$$ {f}^{\boldsymbol{\tau}}(L)\mathbf{b} $$, where L$$ L $$ is the discretization matrix of the spatial operator, b$$ \mathbf{b} $$ a prescribed vector, and fτ$$ {f}^{\boldsymbol{\tau}} $$ a parametric function, such as a fractional power or the Mittag‐Leffler function. In the abstract framework of Stieltjes and complete Bernstein functions, to which the functions we are interested in belong to, we apply a rational Krylov method and prove uniform convergence when using poles based on Zolotarëv's minimal deviation problem. The latter are particularly suited for fractional diffusion as they allow for an efficient query of the map τ↦fτ(L)b$$ \boldsymbol{\tau} \mapsto {f}^{\boldsymbol{\tau}}(L)\mathbf{b} $$ and do not degenerate as the fractional parameters approach zero. We also present a variety of both novel and existing pole selection strategies for which we develop a computable error certificate. Our numerical experiments comprise a detailed parameter study of space‐time fractional diffusion problems and compare the performance of the poles with the ones predicted by our certificate. [ABSTRACT FROM AUTHOR]

Temporary streams are affected by increasing human alterations, and this situation is expected to worsen under global change. Understanding biodiversity trends and the contribution of sites and species to β‐diversity is of high importance in establishing conservation priorities at a regional scale.This paper focuses on aquatic macroinvertebrate biodiversity in temporary streams on the island of Mallorca, using a space–time framework. Differences in α‐diversity, spatial–temporal fluctuations of β‐diversity, local contribution to β‐diversity (LCBD) and species contribution to β‐diversity (SCBD) were examined.Data analysis shows that only the space–time approach to β‐diversity can capture the full variation of macroinvertebrate composition in temporary streams. This confirmed our hypothesis that β‐diversity patterns are better explained by incorporating the temporal dimension to the space–time approach.Regarding β‐diversity components, species replacement components always dominate over richness difference. These results imply that β‐diversity variability is mainly caused by differences in species composition, while the relative difference in richness among sites has a minor role. Consequently, the optimal conservation strategy requires the protection of several undisturbed sites.Although the LCBD analysis did not detect any keystone sites, it helped to identify those sites that should be prioritized for restoration efforts (sites with high LCBD values and low α‐diversity). We also concluded that SCBD analysis should be interpreted carefully, as rare endemic species had low SCBD values.This study demonstrated the need for incorporating temporal variability in the analysis of biodiversity patterns in highly dynamic ecosystems, such as temporary streams. It also revealed the urgency of preserving a spatial network of temporary streams under non‐impaired conditions that can act as dispersal point sources to other streams for biodiversity conservation. These insights are relevant for Mallorca and other Mediterranean islands, and for the protection of temporary rivers elsewhere. [ABSTRACT FROM AUTHOR]

A quantum ranging protocol to determine the distance between an observer and a target in the near‐Earth curved spacetime is proposed. Unlike quantum illumination, the quantum ranging scheme utilizes multiple quantum hypothesis testing to simultaneously determine the presence and location of the target. The interest is in how the Earth's spacetime curvature influences photon propagation as well as the performance of the quantum ranging. It is found that the maximum potential advantage of the quantum ranging strategy in the curved spacetime outperforms its flat spacetime counterpart. It is shown that the number of transmitted modes can enhance the maximum potential advantage of the quantum ranging tasks. In contrast, the maximum potential advantage of quantum ranging cannot be significantly increased by dividing the range into multiple slices in the curved spacetime. [ABSTRACT FROM AUTHOR]

A detailed analysis of the phase‐space for the field equations in scalar field cosmology with a chameleon cosmology in a spatially flat Friedmann–Lemaître–Robertson–Walker spacetime is presented. For the matter source it is assumed that it is an ideal gas with a constant equation of state parameter, while for the scalar field potential and the coupling function of the chameleon mechanism it is considered that four different sets which provide four different models. The H‐normalization approach and the field equations with the help of dimensionless variables written is considered. The asymptotic solutions are determined from where the theory can describe the main eras of cosmological history and evolution that are found. Future attractors which describe acceleration exist; however, acceleration solutions related to the inflationary era is found in past, as also the radiation epoch and the matter dominated eras are provided by the dynamics. The Chameleon dark energy model can be used as a unified model for the elements which contribute to the dark sector of the universe that are concluded. [ABSTRACT FROM AUTHOR]