Spatiotemporal Research Articles

Seismicity of a relic slab: space–time cluster analysis in the Vrancea Seismic Zone

The Vrancea Seismic Zone (VSZ) is an atypical intermediate-depth earthquake nest located in the South-East Carpathians in Romania, often regarded as a relic slab sinking into the mantle. The origin of the slab and the earthquakes it produces are debated because brittle failure is unlikely to occur at mantle depths. Cluster types and statistical properties of seismicity can vary with deformation regime, fluid content and temperature. Here we investigate the spatial–temporal properties of earthquakes recorded in the VSZ from a high-quality local catalogue, identify and classify earthquake clusters, placing constraints on the debated nature of the Vrancea slab, its coupling with the overlying crust, and its potential for triggering crustal earthquakes. We use the nearest-neighbour distance to estimate the correlation between pairs of earthquakes, considering the origin time, magnitude, b-value and fractal dimension of the observed seismicity with Mw ≥ 2.5 from the 1977–2023 period. With this approach, we find a small percentage of clustered seismicity (8%), suggesting that background seismicity dominates. We identified 12 conventional mainshock-dominated sequences and 17 swarms with relatively small (0.92) and large (1.73) b-values, respectively, that may reflect differences in stress or the presence of fluids in the crustal volume. The aftershock decays—p-values of 0.99 for the large-event clusters and 1.42 for the swarms—may reflect typical and, respectively, fast stress relaxations. Swarm clusters are predominantly localised within the crust, whereas conventional mainshock sequences lack foreshocks and prevail in the subcrustal domain, occasionally triggering aftershocks at shallower depths. This partitioning suggests higher heat flow and fluid-modulated seismicity in the crust, as opposed to brittle failure conditions, triggered by slab dynamics in the mantle, including abrupt stress release without preceding signals. The spread of aftershocks from subcrustal large mainshocks to shallower depths indicate a stress transfer process where the descending Vrancea slab influences seismic activity in the overlying crust.Graphical

A Unified Model of Natural Evolution and the Crises in Particle Physics and Cosmology

A unified model of the evolution of the universe is presented. The model consists of four stages: Planckian, Einsteinian, Darwinian, and Intellectual. The evolution of the universe is described as a single flow of information processing that begins at the Planckian stage and continues into the emergence of the most complex information processor: the human brain and the technologically developed human civilization. Each stage has its own structural and functional unit, carriers of evolutionary information, and driving evolving objects. The Planckian stage is described as a system of quantum-mechanically entangled PlanckITs: an entity that represents existence in a randomized space and randomized time. The space-time continuum is presented as a collection of addressable PlanckYTEs. APlanckYTE contains a fixed number of PlanckITs. In the Einsteinianstage, the leptons and quarks of the latest appeared generation carry the information that define the conditions for the transition to the Darwinian stage. Leptons and quarks code a set of parameters that define the conditions for the origin of life and its subsequent evolution. The following expression: ME = (9ℏc3)/(2αGkTE) is one of the results that supports this fact. The Darwinian stage describes biological evolution. The intellectual stage uses the concepts of life symmetry and intellectual fields to describes the intellectual or cultural evolution of social systems. This paper is the first of three papers: ”A Unified Model of Natural Evolution and the Crises in Particle Physics and Cosmology”; ”Space and Time at Planck’s Scale, Carriers of the Evolutionary Information, and the Evolution of the Universe”; ”Evolutionary Anthropodynamics: The Evolution of Intellectual Systems”. Some calculations are done to support the unified model of natural evolution.

Behavior of optical parametric amplification of space-time wave packets

The space-time wave packet (STWP) is a type of pulsed optical field, exhibiting distinctive characteristics, including the capacity to propagate without diffraction or dispersion and to have arbitrary group velocities. However, the intensity of the STWP is constrained by the low damage threshold of some indispensable optical elements like the spatial light modulator (SLM). While optical parametric amplification (OPA) has been proposed for amplifying STWPs, spatio-temporal (ST) characteristics of amplified STWPs remain significantly unexplored. In this article, we investigate the effects of OPA on STWPs and examine how key parameters influence the amplification results. Based on the numerical simulation results, we propose two methods to reduce the duration of the amplified STWP and one method to amplify the STWP with higher group velocities. These findings could facilitate the application of STWPs in strong-field optics.

Wireless Communication Techniques for Improved Detection Fidelity in Microfluidic Impedance Cytometry Using Space–Time Coded Electrodes

Wireless Communication Techniques for Improved Detection Fidelity in Microfluidic Impedance Cytometry Using Space–Time Coded Electrodes

One point functions in large N vector models at finite chemical potential

Abstract We evaluate the thermal one point function of higher spin currents in the critical model of U(N) complex scalars interacting with a quartic potential and the U(N) Gross-Neveu model of Dirac fermions at large N and strong coupling using the Euclidean inversion formula. These models are considered in odd space time dimensions d and held at finite temperature and finite real chemical potential μ measured in units of the temperature. We show that these one point functions simplify both at large spin and large d. At large spin, the one point functions behave as though the theory is free, the chemical potential appears through a simple pre-factor which is either cosh μ or sinh μ depending on whether the spin is even or odd. At large d, but at finite spin and chemical potential, the 1-point functions are suppressed exponentially in d compared to the free theory. We study a fixed point of the critical Gross-Neveu model in d = 3 with 1-point functions exhibiting a branch cut in the chemical potential plane. The critical exponent for the free energy or the pressure at the branch point is 3/2 which coincides with the mean field exponent of the Lee-Yang edge singularity for repulsive core interactions.

A Novel Space–Time Nonlocal Thermo-Viscoelastic Model with Two-Phase Lags for Analyzing Heat Diffusion in a Half-Space Subjected to a Heat Source

A Novel Space–Time Nonlocal Thermo-Viscoelastic Model with Two-Phase Lags for Analyzing Heat Diffusion in a Half-Space Subjected to a Heat Source

Connectivity, Reliability and Approachability in Public Transport: Some Indicators for Improving Sustainability

The reliability of public transport connectivity is influenced by factors such as route design, frequency, availability and infrastructure. Using a shortest path algorithm, we identify up to “k” space–time paths for each origin–destination pair (OD), considering schedules and maximum tolerable waiting times. We propose four reliability indicators and an approachability indicator to assess transport supply. These indicators are calculated at path, OD and network levels using two sets of equations. This framework enables fleet managers to evaluate and compare strategies to improve connectivity reliability and equity, such as increasing route frequency, optimizing lengths or expanding the network. Enhancing connectivity reliability encourages modal shifts to public transport, while improving approachability minimizes resource usage, contributing to sustainability. An application to the bus network of a city in Brittany, France, demonstrates the practical use of these indicators in evaluating and optimizing transport strategies.

An Overview of the CMS High Granularity Calorimeter

Calorimetry at the High Luminosity LHC (HL-LHC) faces many challenges, particularly in the forward direction, such as radiation tolerance and large in-time event pileup. To meet these challenges, the CMS Collaboration is preparing to replace its current endcap calorimeters from the HL-LHC era with a high-granularity calorimeter (HGCAL), featuring an unprecedented transverse and longitudinal segmentation, for both the electromagnetic and hadronic compartments, with 5D information (space–time–energy) read out. The proposed design uses silicon sensors for the electromagnetic section (with fluences above 1016 neq/cm2) and high-irradiation regions (with fluences above 1014 neq/cm2) of the hadronic section, while in the low-irradiation regions of the hadronic section, plastic scintillator tiles equipped with on-tile silicon photomultipliers (SiPMs) are used. Full HGCAL will have approximately 6 million silicon sensor channels and about 280 thousand channels of scintillator tiles. This will allow for particle-flow-type calorimetry, where the fine structure of showers can be measured and used to enhance particle identification, energy resolution and pileup rejection. In this overview we present the ideas behind HGCAL, the current status of the project, results of the beam tests and the challenges that lie ahead.

Use of Immunostimulants in Shrimp Farming-A Bioeconomic Perspective.

Aquaculture is the fastest-growing food industry worldwide because it allows faster intensive production in a limited space and short time. However, the trade-off of this production scheme has led to infectious disease outbreaks that harm food production with economic impacts. Immunostimulants have entered the industry to fight against diseases by enhancing the immune system and conferring better protection against pathogens. In this regard, dietary immunostimulants have been tested at the farm level, such as carbohydrates and proteins known to enhance immunity and improve survival rates under experimental conditions. Despite the success of immunostimulant inclusion in experimental aquaculture, economic evaluation is an innovative avenue to be integrated when a novel immunostimulant is developed. The bioeconomic analysis permits the accurate demonstration of advantages or disadvantages regarding survival and yield performance upon immunostimulant application through mathematical and statistical estimates. An integrative bioeconomic model for testing a novel immunostimulant should contemplate technological, biological, and economic submodels at least; thus, financial variables, such as revenue, costs, and profitability, should also be considered for proper decision-making. Therefore, this perspective briefly describes the most relevant immunostimulants used in shrimp farms and offers bioeconomic elements that should be considered for affordable immunostimulant development and inclusion in shrimp aquaculture.

Space–Time Analysis of Urban Green Spaces’ Disappearance in Ilorin, Nigeria

In recent years, urban green spaces (UGS) have fought for relevance and dominance with competing urban development agendas, which have often proclaimed moral victory, favoring competing interests over the need for UGS. This study examined the decline of UGS between 1986 and 2020 in Ilorin, Nigeria. The methodology employed survey (population estimates) and remotely sensed satellite data (Landsat imagery). The study estimated the UGS decline, land surface temperature (LST) and normalized difference vegetation index (NDVI) for Ilorin from images retrieved from Landsat 5, 7, and 8 thermal infrared sensors using the mono window algorithm and green spaces. Findings revealed the drastic depletion of green spaces, as the combined average reduction effect of riparian and densely vegetated green areas, woodlands, and agricultural sites took place at the rate of 3.37 percent. In comparison, built-up and gray spaces increased by an average of 4.90 percent over the study periods increasing the average LST from 38 °C to over 40 °C. With staunch assurances, Ilorin is on pace to lose 9.51 hectares before 2030. Conclusively, governments and city managers must do enough through environmental investments by revising policies that produce new results that can improve the roles of UGS in ecosystem services provision.

Bromocriptine mesylate-loaded nanoparticles co-modified with low molecular weight protamine and lactoferrin for enhanced nose-to-brain delivery in Parkinson's disease treatment.

Parkinson's disease confronts challenges in drug delivery due to the blood-brain barrier. Intranasal delivery bypasses the blood-brain barrier for improved drug bioavailability, yet narrow nasal space and brief retention time hinder clinical applicability. We conducted a Bromocriptine Mesylate-loaded PLGA nanoparticles co-modified with low molecular weight protamine (LMWP) and lactoferrin (Lf) (LMWP/Lf-BCM-NPs) for nose-to-brain delivery. The resulting LMWP/Lf-BCM-NPs were uniform spheres with an average size of 248.53±16.25nm and zeta potential of -2.63±0.74mV. Fourier transform infrared spectroscopy confirmed LMWP and Lf attachment. The co-modified nanoparticles showed improving cellular transport and good viability. The LMWP/Lf-BCM-NPs showed increased brain targeting efficiency in mice. In haloperidol-induced Parkinson mouse models, the LMWP/Lf-BCM-NPs showed increased brain targeting efficiency, enhanced behavioral regulatory effects, enhanced antioxidant effects and neuroprotection effects. This study paves the way for a novel, non-invasive brain-targeted therapy, offering a promising avenue for Parkinson's disease clinical treatment.

Heterogeneously catalyzed lignin depolymerisation in continuous flow: Assessing feedstock pretreatment and catalyst deactivation

Due to the large-scale production of lignin, continuous flow reactors are preferred for its further valorization through depolymerization. However, there is limited literature on their use in lignin depolymerization, especially concerning feedstock pretreatments and catalyst deactivation. Therefore, in this study, the impact of a batch solvolysis pretreatment on the mild reductive catalytic depolymerization of Soda lignin, with and without a Pd catalyst, is evaluated and catalyst deactivation is systematically assessed. The Pd catalyst substantially enhances Mw reductions, e.g., without feedstock pretreatment, it increases the Mw reduction from approximately 70 % to 90 % at low time-on-streams (T.O.S.). It also yields products with more functionalities from the untreated feedstock, i.e., at low T.O.S., the phenolic and aliphatic OH content increases from 4.21 to 4.89 mmol/g and 2.30 to 3.72 mmol/g, respectively. The differences are less pronounced with the pretreated feedstock due to condensation of the lignin structure. Furthermore, the high space–time that can be achieved at a short residence time negates the need for a pretreatment. Regarding deactivation, no significant Pd leaching or poisoning by S or Na was observed. The Pd nanoparticles grew from about 8 nm to 20 nm (pretreated feed) and 17 nm (untreated feed), which is likely due to the phase change from PdO to metallic Pd rather than deactivation through sintering. The support material changed from γ-Al2O3 to boehmite, leading to the loss of acid sites and morphological changes. While some indications for small amounts of coke deposits were observed, they could not be differentiated from interstitial water within the boehmite structure. Thus, the main cause for deactivation of the Pd catalyst was identified to be the hydrothermal instability of the alumina support.

Analysis of desert locust (Schistocerca gregaria) suitability in Yemen: an integrated evaluation based on MaxEnt and space–time cube approaches

ABSTRACT Desert locust outbreaks pose severe threats to agricultural production and ecological environments. Hence, understanding the distribution of habitat suitability is crucial for establishing effective prevention and control measures. We introduce an innovative method for analyzing the temporal and spatial variations of desert locust habitat suitability in Yemen. This method integrates ecological niche models with space–time cube analysis. First, we gathered key environmental variables that affect desert locust distribution, including vegetation and soil types, precipitation, and temperature. Subsequently, we employed the MaxEnt model to assess habitat suitability for desert locusts in Yemen for 2010 and 2013–2021. Finally, we applied the space–time cube method for spatiotemporal analysis to reveal the spatiotemporal dynamics of habitat suitability distribution. The MaxEnt model results showed that the kappa coefficients exceeded 0.46 and the area under the curve exceeded 0.75. The spatiotemporal analysis results showed that from 2010 to 2021, the Red Sea coastal plains in western Yemen exhibited the highest habitat suitability levels, with significant increases in habitat suitability in the western and central regions. This study offers a new perspective on studying the spatial and temporal characteristics of desert locust habitat suitability distribution and can provides a scientific basis for the management of desert locusts.

In Ukrainian

Experimental methodology of the thermal vacuum process is that in order to obtain effective and economical production of nanomaterials, it is necessary to ensure a continuous flow of dispersed material inside the heating spiral element. This can done if the material enters the cavity of the heating element together with air. A two-phase system of gas-solid particles arises. The movement occurs in an ascending flow in a heated space with a constant decrease in pressure for 15 s. The results of the studies show that the velocity of material particles in the cavity of spiral heating element of the thermal vacuum unit depends on the thermal radiation of the heater walls, the energy of a local pulsed steam explosion with the appearance of a shock wave, which forms a significant number of nanodispersed and finely dispersed bodies. The greater the energy of the local explosion, the higher the velocity of the material particle, the greater the angle of incidence of the particle on the opposite wall of the heating element. Locally, the temperature of the external environment increases, the kinetic energy of material particles grows, and the flow of electrons, protons, and other charged particles accelerates significantly. A plasma clot is formed, a neutrino cloud is emitted. Nanoparticles take the form of nanotubes, fullerenes, thin films, crystals. It been established that the dispersed material in the thermal vacuum unit is successively affected by force, heat, deformation, ionization effects, which allows accelerating the process of obtaining nanodispersed materials. Each physical process in a thermal vacuum installation has its own space-time continuum and it is necessary to take into account only those characteristics that correspond to a specific interaction.

The Speed-Time-Space Structure Curve (Kepler's Law)

According to Einstein everybody make a curve in space. This curve is the case of gravity. A large body make a large curve. If the body is in velocity than space time curve should be small in the direction of velocity and large in the opposite direction.

Comparative evaluation of spatiotemporal methods for effective dengue cluster detection with a case study of national surveillance data in Thailand

Dengue fever poses a significant public health burden in tropical regions, including Thailand, where periodic epidemics strain healthcare resources. Effective disease surveillance is essential for timely intervention and resource allocation. Various methods exist for spatiotemporal cluster detection, but their comparative performance remains unclear. This study compared spatiotemporal cluster detection methods using simulated and real dengue surveillance data from Thailand. A simulation study explored diverse disease scenarios, characterized by varying magnitudes and spatial-temporal patterns, while real data analysis utilized monthly national dengue surveillance data from 2018 to 2020. Evaluation metrics included accuracy, sensitivity, specificity, positive predictive value, and negative predictive value. Bayesian models and FlexScan emerged as top performers, demonstrating superior accuracy and sensitivity. Traditional methods such as Getis Ord and Moran’s I showed poorer performance, while other scanning-based approaches like spatial SaTScan exhibited limitations in positive predictive value and tended to identify large clusters due to the inflexibility of its scanning window shape. Bayesian modeling with a space–time interaction term outperformed testing-based cluster detection methods, emphasizing the importance of incorporating spatiotemporal components. Our study highlights the superior performance of Bayesian models and FlexScan in spatiotemporal cluster detection for dengue surveillance. These findings offer valuable guidance for policymakers and public health authorities in refining disease surveillance strategies and resource allocation. Moreover, the insights gained from this research could be valuable for other diseases sharing similar characteristics and settings, broadening the applicability of our findings beyond dengue surveillance.

Heuristic-based vehicle arrangement for ro-ro ships

In this paper, a two-level search strategy fused with an improved no-fit polygon algorithm and improved bat algorithm is proposed to obtain the layout points of multiple vehicles. Additionally, a space–time scheduling strategy is proposed using the Improved D*Lite Algorithm (ID*Lite) and improved Bezier curve to generate the trajectories of individual vehicles. Furthermore, a conflict resolution strategy is introduced to address the collision conflict problem during multi-vehicle scheduling. The proposed strategies aim to achieve the objectives of shortest scheduling time and smallest array space in order to reduce the time and space cost of vehicle loading on ro-ro carriers. Through a comparison with other algorithms (e.g., at high loading pressure, Scenario 3), the strategies presented in this paper demonstrate advantages such as higher deck utilization (92.234%), shorter path length, fewer collision conflicts, and more balanced weighting. Mainstream methods only focus on a certain part of vehicle transportation, we not only use more stable parking spot generation algorithm and parking order generation algorithm, but also more high-speed multi-vehicle path-finding algorithm, path optimization strategy, multi-vehicle scheduling strategy, which innovatively form a complete vehicle planning process, and at the same time, as an algorithmic framework that can be generalized to any 2d or 3d scenarios.

Discontinuous Galerkin discretization of coupled poroelasticity–elasticity problems

Abstract This work is concerned with the analysis of a space–time finite element discontinuous Galerkin method on polytopal meshes (XT-PolydG) for the numerical discretization of wave propagation in coupled poroelastic–elastic media. The mathematical model consists of the low-frequency Biot’s equations in the poroelastic medium and the elastodynamics equation for the elastic one. To realize the coupling suitable transmission conditions on the interface between the two domains are (weakly) embedded in the formulation. The proposed PolydG discretization in space is coupled with a dG time integration scheme, resulting in a full space–time dG discretization. We present the stability analysis for both semidiscrete and fully discrete formulations, and derive error estimates in suitable energy norms. The method is applied to various numerical test cases to verify the theoretical bounds. Examples of physical interest are also presented to investigate the capability of the proposed method in relevant geophysical scenarios.

Continuous flow synthesis of di‐tert‐butyl peroxide in microreactors and kinetic study

AbstractDi‐tert‐butyl peroxide (DTBP) is a widely used organic peroxide. Its synthesis using tert‐butyl alcohol (TBA) and H2O2 via traditional batch processes has suffered from low space–time yield, uncontrollable product distribution, and safety issues. An efficient continuous‐flow microreaction system was proposed to enhance DTBP synthesis. Optimal reaction conditions were determined: a molar ratio of 1.5 (H2SO4/TBA) and 0.5 (H2O2/TBA), a reaction temperature of 50°C, and concentrations of 75 wt% H2SO4, 85 wt% TBA, and 50 wt% H2O2. A kinetic model was established, indicating that reducing local H2O2 concentration is key to increasing space‐time yield. Consequently, a novel two‐stage H2O2 feeding strategy was proposed, which improved the DTBP selectivity from 94.7% to 97.6% compared to the single‐stage feeding process. The maximum TBA conversion reached upto 98.7% within only 410 s, with a DTBP yield of 96.3%. With proper design and optimization, this microreaction system could be further applied to continuously synthesize other dialkyl peroxides.

Application of Multidomain Cognitive Training in a Tele-Neurorehabilitation Setting for Treatment of Post-Stroke Cognitive Disorders.

Cognitive dysfunctions are still very common in the chronic phase of stroke when patients are discharged from neurorehabilitation centers. Even individuals who appear to have made a full clinical recovery may exhibit new deficiencies at home. Here, we present evidence of a novel kind of therapy at home aimed at contrasting the heterogenic evolution of stroke patients using a multidomain cognitive approach. Eighteen ischemic stroke patients were assessed in a within-subject longitudinal design (age 62.33 ± 11.1 years; eight men). Patients underwent the Tele-NeuroRehabilitation (TNR) multidomain cognitive training treatment using the Virtual Reality Rehabilitation System (VRRS) five times a week for 1 h sessions for four consecutive weeks. The protocol included the stimulation of specific cognitive functions, such as logical skills, praxis skills, attention, executive functions, memory, space time orientation and perception, and speech therapy. To determine neuropsychological changes, patients were evaluated before the sessions (T0), at the end of the sessions (T1), and after six months (T2). The multidomain cognitive training induced a significant improvement in the working memory and language abilities as well as depression symptoms and alleviated caregiver burden. Most of this cognitive enhancement persisted after six months (T2), with the exception of depression symptoms. Otherwise, a significant decline in attention abilities was reported, thus demonstrating a lack of effect in this function. Our results suggest that multidomain cognitive TNR is a suitable protocol for reducing some cognitive and behavioral alterations in patients with strokes, with a beneficial impact also on the caregivers' burden distress management. Further RCTs are warranted to validate this new kind of approach.