Temporal Transformation Research Articles

Supercontinuum saturation of a femtosecond laser filament in pressurized gases.

Filamentation of high-power femtosecond optical pulses in high-pressure gases has gained increasing academic and practical interest from the viewpoint of studying large-scale spectral and temporal transformations occurring with pulsed laser radiation and obtaining super-broadened spectra and extremely short (attosecond) wave packets. Experimentally and theoretically, for the first time to the best of our knowledge, we show that as a result of a 45 fs Ti:sapphire laser pulse filamentation in an optical cell filled with pressurized up to 50 bar nitrogen or argon, the pulse spectrum can reach maximally about eightfold broadening. This limiting pulse spectral width is reached at a gas pressure of about 20 bar and with further pressure increase exhibits saturation and even a slight decrease relative to the limiting value. As a possible reason for this finding, we suppose the increase of pulse energy depletion in the self-created plasma at high gas pressure.

LS-VIT: Vision Transformer for action recognition based on long and short-term temporal difference.

Over the past few years, a growing number of researchers have dedicated their efforts to focusing on temporal modeling. The advent of transformer-based methods has notably advanced the field of 2D image-based vision tasks. However, with respect to 3D video tasks such as action recognition, applying temporal transformations directly to video data significantly increases both computational and memory demands. This surge in resource consumption is due to the multiplication of data patches and the added complexity of self-aware computations. Accordingly, building efficient and precise 3D self-attentive models for video content represents as a major challenge for transformers. In our research, we introduce an Long and Short-term Temporal Difference Vision Transformer (LS-VIT). This method incorporates short-term motion details into images by weighting the difference across several consecutive frames, thereby equipping the original image with the ability to model short-term motions. Concurrently, we integrate a module designed to understand long-term motion details. This module enhances the model's capacity for long-term motion modeling by directly integrating temporal differences from various segments via motion excitation. Our thorough analysis confirms that the LS-VIT achieves high recognition accuracy across multiple benchmarks (e.g., UCF101, HMDB51, Kinetics-400). These research results indicate that LS-VIT has the potential for further optimization, which can improve real-time performance and action prediction capabilities.

Spatial–Temporal Variations in Water Use Efficiency and Its Influencing Factors in the Li River Basin, China

As a vital indicator for measuring the coupled carbon–water cycle of an ecosystem, water use efficiency (WUE) can also reflect the adaptive capacity of plants in different ecosystems. Located in Southwest China, the Li River Basin has a representative karst landform, and the uneven rainfall in the region leads to severe water shortage. In this study, we analyzed the spatial–temporal transformation characteristics of the WUE of the basin and its relationship with different influencing factors from 2001 to 2020 based on a correlation analysis and trend analysis. The main conclusions are as follows: (1) The average value of WUE in the Li River Basin was 1.8251 gC· mm−1·m−2, and it kept decreasing at a rate of 0.0072 gC· mm−1·m−2·a−1 in the past 20 years. With respect to the spatial distribution of the multi-year average of WUE, it exhibits a gradual increasing trend from west to east. (2) Between gross primary productivity (GPP) and evapotranspiration (ET), it was found that ET was the primary influencing factor of WUE. Precipitation was positively correlated with WUE in the Li River Basin, accounting for 67.22% of the total area of the basin. The air temperature was negatively correlated with WUE, and the area was negatively correlated with WUE, accounting for 92.67% of the basin area. (3) The normalized difference vegetation index (NDVI) and leaf area index (LAI) were negatively correlated with WUE, and the proportions of negatively correlated areas to the total area of the basin were similar; both were between 60 and 70%. The growth of vegetation inhibited the increase in WUE in the basin to a certain extent. Regarding Vapor Pressure Deficit (VPD), the proportions of positive and negative correlation areas with WUE were similar, accounting for 49.58% and 50.42%, respectively. (4) The occurrence of drought events and the enhancement in its degree led to a continuous increase in WUE in the basin; for different land cover types, the correlation of the standardized precipitation evapotranspiration index (SPEI) was in the following order from strongest to weakest: grassland > cropland > forest > shrubland.

Bisphenol F-induced precocious genesis of aggressive neurobehavioral response is associated with heightened monoamine oxidase activity and neurodegeneration in zebrafish brain

The production and use of plastics and plastics products has increased dramatically in recent decades. Moreover, their unprotected disposal into ambient life sustaining environment poses a significant health risk. Bisphenol F (BPF) an alternative to bisphenol A (BPA) has been extensively employed for making of plastics. Recent reports have documented the neurotoxic potential of BPF through induction of altered neurochemical profile, microglia-astrocyte-mediated neuroinflammation, oxidative stress, transformed neurobehavioral response, cognitive dysfunction, etc. In the present study, our approach was to understand the underlying mechanism of BPF-persuaded genesis of aggressive neurobehavioral response in zebrafish. The basic findings advocated a temporal transformation in native explorative behaviour and progressive induction of aggressive behavioural response in zebrafish following exposure to BPF. Our neurobehavioral findings supported the argument of oxidative stress-mediated neuromorphological transformation in the periventricular grey zone (PGZ) of the zebrafish brain. In line with earlier reports, our findings also showed that heightened monoamine oxidase (MAO) activity and downregulation in tyrosine hydroxylase expression in the zebrafish brain is associated with the precocious genesis of aggressive neurobehavioral response in zebrafish brain. Our findings also shed light on BPF-instigated apoptotic neuronal death as revealed by augmented chromatin condensation and cleaved caspase-3 expression. Further observation showed that the downregulation of NeuN (a marker of post-mitotic mature neuron) expression provided substantial neurotoxicity, leading to neurodegeneration in the PGZ region of the zebrafish brain. These basic findings grossly advocate that BPF acts as a potent neurotoxicant in transmuting native neurobehavioral response through the induction of oxidative stress, heightened MAO activity and neuromorphological transformation in the zebrafish brain.

Navigating Labour Shifts: Early Modern Pearl Fishing in the Caribbean (1521–1563)

Abstract Narratives about indigenous labour in the pearl fisheries of the Caribbean, widely disseminated across the Atlantic world since the sixteenth century by Castilian chroniclers, have significantly shaped historiography. These accounts have reinforced a singular narrative about labour within pearl fisheries that overlooks this work's spatial and temporal changes in sea depths. This article examines and reconstructs the labour practices of workers in the pearl fisheries on the islands of Cubagua, Margarita, and Coche, as well as the coast of Cabo de la Vela and Riohacha, highlighting their temporal and spatial transformations. Additionally, it analyses the coexistence of various forms of coerced labour within this context.

Realistic mossy fiber input patterns to unipolar brush cells evoke a continuum of temporal responses comprised of components mediated by different glutamate receptors.

Unipolar brush cells (UBCs) are excitatory interneurons in the cerebellar cortex that receive mossy fiber (MF) inputs and excite granule cells. The UBC population responds to brief burst activation of MFs with a continuum of temporal transformations, but it is not known how UBCs transform the diverse range of MF input patterns that occur in vivo. Here we use cell-attached recordings from UBCs in acute cerebellar slices to examine responses to MF firing patterns that are based on in vivo recordings. We find that MFs evoke a continuum of responses in the UBC population, mediated by three different types of glutamate receptors that each convey a specialized component. AMPARs transmit timing information for single stimuli at up to 5 spikes/s, and for very brief bursts. A combination of mGluR2/3s (inhibitory) and mGluR1s (excitatory) mediates a continuum of delayed, and broadened responses to longer bursts, and to sustained high frequency activation. Variability in the mGluR2/3 component controls the time course of the onset of firing, and variability in the mGluR1 component controls the duration of prolonged firing. We conclude that the combination of glutamate receptor types allows each UBC to simultaneously convey different aspects of MF firing. These findings establish that UBCs are highly flexible circuit elements that provide diverse temporal transformations that are well suited to contribute to specialized processing in different regions of the cerebellar cortex.

Evolution of Land Use and Land Cover Change in Panjim, Goa: A Comparative Analysis from 1990 to 2024

This research paper investigates the dynamics of land use and land cover (LU/LC) change in Panjim, Goa, India, from 1990 to 2024. Using satellite Data and GIS techniques, the study analyzes the spatial and temporal transformations of land cover categories, including forest, agriculture, urban areas, and water bodies. The primary objective is to understand the drivers of LU/LC change and assess their implications for sustainable urban development and environmental conservation. The findings reveal significant urban expansion, encroachment on agricultural lands, and reduction in forest cover. The study highlights the need for effective land use planning and management strategies to mitigate negative environmental impacts and ensure the city's long-term sustainability. Keywords: Land Use, Land Cover, Supervised Classification, Change Detection, Accuracy Assessment

Prescribed-time fully distributed Nash equilibrium seeking of nonlinear multi-agent systems over unbalanced digraphs

This paper investigates the prescribed-time fully distributed Nash equilibrium seeking (PT-FDNES) problem for nonlinear multi-agent systems (MASs) over weight-unbalanced directed graphs (digraphs). To counterbalance unweighted communication flows caused by the unbalanced network, the temporal transformation technique is first introduced to derive a consensus-based algorithm for calculating the left eigenvector of the Laplacian matrix, based on which a prescribed-time fully distributed estimator with adaptive gains is developed to obtain the NE without requiring any global information. By utilizing this NE estimator to formulate an intermediate control law, the NE seeking problem is then effectively transformed into a local reference-tracking problem. To deal with the non-differentiability issue caused by the NE estimator and ensure the exact tracking, the dynamic gain technique and novel scaling functions are employed to derive a prescribed-time tracking controller which completely compensates for the mismatched uncertainties while reducing the computational burden. The proposed control framework enables the actions of all agents to reach the NE within a prescribed time. In addition, the obtained results are further re-designed to exhibit the robustness by introducing an improved σ-modification scheme without sacrificing the convergence performance. Numerical examples are provided to demonstrate the validity of the theoretical results.

Unveiling the frontiers: Historical expansion and modern implications of agricultural land use in Denmark

This study offers a first-of-its-kind investigation into the spatial and temporal transformation of agricultural land use and expansion in crops and livestock at national scale during the middle and latter half of the 19th century.We introduce an innovative methodological framework that combines historical data with advanced spatial analysis to trace and map the evolution of frontiers of agricultural land use changes, illustrating Denmark's agricultural evolution towards the modern era.Our research uncovers critical shifts in cropland, grazing land, and livestock density offering unprecedented insights into the mechanisms driving agricultural expansion and intensification. The mechanisms driving this expansion and their potential impact on contemporary agroecological challenges linked to land use intensification are explored. Our results point to a significant broadening and shifting of land use frontiers offering a historical perspective on agricultural land use. This sets the stage for promoting the analysis of drivers of change and gaining insights into how landscape development could be steered into an environmentally and societally more desirable and sustainable direction tackling present-day agroecological challenges.

Geometric prescribed‐time control of quadrotors with adaptive extended state observers

AbstractThis article studies an adaptive extended state observer (AESO) based prescribed‐time geometric attitude stabilization problem of quadrotors with endogenous uncertainties, exogenous disturbances, and actuator saturation, which can be estimated and compensated by AESOs. The employment of the geometric representation method for system attitude can effectively avoid ambiguity or singularity problems that may arise with other representations. The temporal and scale transformations are employed to solve the global boundedness problem on infinite time instead of the prescribed‐time convergence problem on finite time. By integrating the proposed controller with the backstepping technique, the system of quadrotors can be prescribed‐time stable. Further, a prescribed‐time geometric attitude control technique is devised such that the control signal is bounded and the state signals converge to a small domain near the equilibrium point in the prescribed time. The prescribed time is determined by the user and is independent of the initial conditions. The comparative simulations with different initial information are performed to demonstrate the effectiveness of the proposed design technique.

Spatial and temporal transformations of resource‐producing subjects of the Russian Federation in 2012–2021

Allocation of spatial and temporal transformations in resource‐producing subjects of the Russian Federation for the decade 2012–2021 based on the comparison of tax revenue materials with budget execution data.The materials of the study were information from the Federal Tax Service of the Russian Federation, Form 1, regulatory legal acts. The values for 2 federal taxes were used as incoming tax revenues: corporate income tax and personal income tax. Research methods were: comparative, computational and cartographic.During the period under review, 13 territories were assigned at least once to the group with high raw materials specialisation, for which negative features of response to external challenges are inherent:‐ there was not a single subject of the Russian Federation in which the growth of budget expenditures with a proportional and large increase in tax revenues was observed;‐ only in 2018, was an increase in budget expenditures noted for all territories with a simultaneous increase in tax revenues from mining;‐ only in 4 subjects of the Russian Federation budget did expenditures continuously increased, while some members of the group had budget expenditures reduced against the background of the growth of raw material tax revenues.During the period under review, high economic uncertainty and the accompanying transformation in regional policy were revealed, resulting in a change in the number and composition of participants in resourceproducing subjects of the Russian Federation.

Enhancing Peak Runoff Forecasting through Feature Engineering Applied to X-Band Radar Data

Floods cause significant damage to human life, infrastructure, agriculture, and the economy. Predicting peak runoffs is crucial for hazard assessment, but it is challenging in remote areas like the Andes due to limited hydrometeorological data. We utilized a 300 km2 catchment over the period 2015–2021 to develop runoff forecasting models exploiting precipitation information retrieved from an X-band weather radar. For the modeling task, we employed the Random Forest (RF) algorithm in combination with a Feature Engineering (FE) strategy applied to the radar data. The FE strategy is based on an object-based approach, which derives precipitation characteristics from radar data. These characteristics served as inputs for the models, distinguishing them as “enhanced models” compared to “referential models” that incorporate precipitation estimates from all available pixels (1210) for each hour. From 29 identified events, enhanced models achieved Nash-Sutcliffe efficiency (NSE) values ranging from 0.94 to 0.50 for lead times between 1 and 6 h. A comparative analysis between the enhanced and referential models revealed a remarkable 23% increase in NSE-values at the 3 h lead time, which marks the peak improvement. The enhanced models integrated new data into the RF models, resulting in a more accurate representation of precipitation and its temporal transformation into runoff.

Assessing the impact of anthropogenic activities on land use and land cover changes in the semi-arid and arid regions of Algeria.

Land use and land cover are critical factors that influence the environment and human societies. The dynamics of LULC have been constantly changing over the years, and these changes can be analyzed at different spatial and temporal scales to evaluate their impact on the natural environment. This study employs multitemporal satellite data to investigate the spatial and temporal transformations that occurred in Sidi Bel Abbes province, situated in the northwestern region of Algeria, spanning from the early 1990s to 2020. Notably, this province is marked by semi-arid and arid climates and hosts a wide range of areas susceptible to gravitational hazards, especially concerning alterations in land use and forest fires. The interactive supervised classification tool utilized multiple machine learning algorithms including Random Forest, Support Vector Machine, Classification and Regression Tree, and Naïve Bayes to produce land cover maps with six main classes: forest, shrub, agricultural, pasture, water, and built-up. The findings showed that the LULC in the research area is undergoing continuous change, particularly in the forest and agricultural lands. The forest area has decreased significantly from 10.80% in 1990 to 5.25% in 2020, mainly due to repeated fires. Agricultural land has also undergone fluctuations, with a decrease between 1990 and 2000, followed by a fast increase and near stabilization in 2020. At the same time, pasture lands and built-up areas grew steadily, increasing by 11% and 13% respectively. This research highlights the significant impact of anthropogenic activities on LULC changes in the study area and can provide valuable insights for promoting sustainable land use policies.

Investigating Nonlinear Dynamics in Atmospheric Aerosols during the Transition from Laminar to Turbulent Flow

This paper investigates the nonlinear dynamics of atmospheric aerosols during the transition from laminar to turbulent flows using the framework of Scale Relativity Theory. It is proposed that the transition from multifractal to non-multifractal scales (in the dynamics of the atmospheric aerosols) can be assimilated to the transition between laminar and turbulent states. These transitions are determined by the multifractal diffusion and deposition processes. The methodology used involves the application of the principle of scale covariance, which states that the laws of atmospheric physics remain invariant with respect to spatial and temporal transformations as well as scale transformations. Based on this principle, several conservation laws are constructed. In such context, the conservation law of the density of states associated with the multifractal-non-multifractal scale transition in a one-dimensional case is then considered. The model describes the non-linear behaviour of atmospheric aerosols undergoing diffusion and deposition processes. The theoretical approach was correlated using experimental data from a ceilometer and radar reflectivity factor data.

Multi-Frame Content-Aware Mapping Network for Standard-Dynamic-Range to High-Dynamic-Range Television Artifact Removal.

Recently, advancements in image sensor technology have paved the way for the proliferation of high-dynamic-range television (HDRTV). Consequently, there has been a surge in demand for the conversion of standard-dynamic-range television (SDRTV) to HDRTV, especially due to the dearth of native HDRTV content. However, since SDRTV often comes with video encoding artifacts, SDRTV to HDRTV conversion often amplifies these encoding artifacts, thereby reducing the visual quality of the output video. To solve this problem, this paper proposes a multi-frame content-aware mapping network (MCMN), aiming to improve the performance of conversion from low-quality SDRTV to high-quality HDRTV. Specifically, we utilize the temporal spatial characteristics of videos to design a content-aware temporal spatial alignment module for the initial alignment of video features. In the feature prior extraction stage, we innovatively propose a hybrid prior extraction module, including cross-temporal priors, local spatial priors, and global spatial prior extraction. Finally, we design a temporal spatial transformation module to generate an improved tone mapping result. From time to space, from local to global, our method makes full use of multi-frame information to perform inverse tone mapping of single-frame images, while it is also able to better repair coding artifacts.

Fluorescence and lasing of neutral nitrogen molecules inside femtosecond laser filaments in air: mechanism and applications.

High power femtosecond laser pulses launched in air undergo nonlinear filamentary propagation, featuring a bright and thin plasma channel in air with its length much longer than the Rayleigh length of the laser beam. During this nonlinear propagation process, the laser pulses experience rich and complex spatial and temporal transformations. With its applications ranging from supercontinuum generation, laser pulse compression, remote sensing to triggering of lightning, the underlying physical mechanism of filamentation has been intensively studied. In this review, we will focus on the fluorescence and cavity-free lasing effect of the plasma filaments in air. The different mechanisms underlying the fluorescence of the excited neutral nitrogen molecules will be throughly examined and it is concluded that the electron collision excitation is the dominant channel for the formation of the excited nitrogen molecules. The recently discovered "air lasing" effect, a cavity-free bidirectional lasing emission emitted by the filaments, will be introduced and its main properties will be emphasized. The applications of the fluorescence and lasing effect of the neutral nitrogen molecules will be introduced, with two examples on spectroscopy and detection of electric field. Finally, we discuss the quenching effect of the lasing effect in atmosphere and the mechanisms responsible will be analyzed. An outlook for the achievement of backward lasing in air will be briefly presented.

A novel tracking and analysis system for time-lapse cellular imaging of Schizosaccharomyces pombe.

The importance of the parent-progeny relationship tracking technique in single-cell analysis has grown with the passage of time. In this study, fundamental image-processing techniques were combined to develop software capable of inferring cell cycle alterations in fission yeast cells, which exhibit equipartition during division. These methods, exclusively relying on bright-field images as input, could track parent-progeny relationships after cell division by assessing the temporal morphological transformation of these cells. In the application of this technique, the software was employed for calculating intracellular fluorescent dots during every stage of the cell cycle, using a yeast strain expressing EGFP-fused Swi6, which binds to chromatin. The results obtained with this software were consistent with those of previous studies. This software facilitated single-cell-level tracking of parent-progeny relationships in cells exhibiting equipartition during division and enabled the monitoring of spatial fluctuations in a cell cycle-dependent protein. This method, expediting the analysis of extensive datasets, may also empower large-scale screening experiments that cannot be conducted manually.

“The Sickness of Hope Deferred”: Infrastructure and Temporality in Bleak House

This essay argues that infrastructures in Charles Dickens's Bleak House (1853) effect temporal accelerations and protractions, as opposed to being connective tissues for spatial and social networks. Reading the law enacted at the court of Chancery and the British Empire's maritime networks, two instances of the novel's many infrastructures, this paper traces infrastructures’ time warps: perpetual deferrals of justice, denials of coevalness to colonial subjects, and accelerations of death for Richard Carstone and other characters. Infrastructures’ temporal transformations reveal how temporalities of varying rhythms are held together under a veneer of uniform linearity by the realist novel's generic attributes like serialized publication and Esther's marriage plot. Attention to this fraught temporality, the author argues, enables readers to glean the extent to which the claims of colonized and subaltern subjects suffuse the novel's narrative voice.

Quantitative Precision Second-Order Temporal Transformation Based Pose Control for Spacecraft Proximity Operations

Quantitative Precision Second-Order Temporal Transformation Based Pose Control for Spacecraft Proximity Operations

Preobrazbe, posrnuća i (zamišljene) budućnosti Gojla i Kutine

The paper presents and examines two localities – Gojlo and Kutina in Croatia – and their spatial, temporal, material, and social transformations throughout the twentieth century to the present. The two localities are linked geographically and by a “shared fate” – as planned cities/settlements for industrial purposes and the extraction of natural resources. After the depletion of resources, the crisis of raw materials, and the transformations of political and economic systems, these localities both experienced spatial and social stagnation and degradation. Gojlo suffered decay, and Kutina has experienced partial deindustrialization. The research questions focus on the dynamic relationship between space/place, time, and top-down urban planning. Critical analysis invokes, and relies on, the concepts and research fields of the (post)industrial city, industrial monoculture, placemaking, anthropology of the future, multiple temporalities, and an anthropology of optimism.