Temporal Adaptation Research Articles

Intermittent social stress produces different short- and long-term effects on effort-based reward-seeking behavior

Previous studies show that intermittent social defeat (ISD) stress increases self-administration of psychostimulants, which suggests that ISD promotes reward-seeking behavior and, ultimately, increases vulnerability to develop drug abuse. The present study investigates whether ISD alters cost/benefit evaluations to promote reward-seeking behavior and whether these alterations are time-dependent. Male rats performed two different tasks that assessed their motivation to seek and consume food rewards. An effort-discounting task in which rats chose between less and more effortful options (i.e., 1 lever-press versus 2, 5, 10 or 20 lever-presses) associated with low- and high-reward (i.e., 1 sugar pellet versus 3 sugar pellets), respectively; and a progressive ratio task in which rats had to increase their effort (more lever presses) to obtain a sugar pellet. ISD consisted of exposing animals to social defeat once every three days for ten days (4 stress episodes). Rats were tested 24–48 h after stress episodes, and 1 week and 6 weeks after the last stress episode. In the effort-discounting task, stressed animals showed a decrease in their preference for high rewards associated with more effort (i.e., 10 and 20 lever-presses). These effects were transient and not maintained one week after stress. In the progressive ratio task, stressed animals showed an increase in the number of lever presses to obtain rewards that emerged six weeks after the last stress episode. These results suggest different short- and long-term effects on the motivation for rewards after ISD and indicate temporal dynamic adaptations in the function of the brain reward system.

A preservative splitting approximation of the solution of a variable coefficient quenching problem

This paper studies the numerical solution of a two-dimensional quenching type nonlinear reaction-diffusion problem via dimensional splitting. The variable coefficient differential equation considered possesses a nonlinear forcing term, and may lead to strong quenching singularities that have profound multiphysics and engineering applications to the energy industry. Our investigations focus on the construction and preservative properties of a semi-adaptive Peaceman-Rachford procedure for solving the aforementioned problem. In the study, the multidimensional differential equation is decomposed into single dimensional subequations so that the computational efficiency can be effectively raised. Temporal adaptation is implemented through arc-length estimations of the rate-of-change of the numerical solution. The positivity, monotonicity and localized linear stability of the variable step splitting scheme are analyzed. These ensure key preservations of underlying physical features of the computed approximations for applications. Computational experiments are presented to illustrate our results as well as to demonstrate the viability and accuracy of the splitting method for solving singular quenching-combustion problems.

Temporal convolution-based transferable cross-domain adaptation approach for remaining useful life estimation under variable failure behaviors

Many data-driven models normally assume that the training and test data are independent and identically distributed to predict the remaining useful life (RUL) of industrial machines. However, different failure models caused by variable failure behaviors may lead to a domain shift. Meanwhile, conventional methods lack comprehensive attention to temporal information, resulting in a limitation. To handle the aforementioned challenges, a transferable cross-domain approach for RUL estimation is proposed. The hidden features are extracted adaptively by a temporal convolution network in which residual self-attention is able to fully consider the contextual degradation information. Furthermore, a new cross-domain adaption architecture with the contrastive loss and multi-kernel maximum mean discrepancy is designed to learn the domain invariant features. The effectiveness and superiority of the proposed method are proved by the case study on IEEE PHM challenge 2012 bearing dataset and the comparison with other methods.

Rapid Transient Transcriptional Adaptation to Hypergravity in Jurkat T Cells Revealed by Comparative Analysis of Microarray and RNA-Seq Data.

Cellular responses to micro- and hypergravity are rapid and complex and appear within the first few seconds of exposure. Transcriptomic analyses are a valuable tool to analyze these genome-wide cellular alterations. For a better understanding of the cellular dynamics upon altered gravity exposure, it is important to compare different time points. However, since most of the experiments are designed as endpoint measurements, the combination of cross-experiment meta-studies is inevitable. Microarray and RNA-Seq analyses are two of the main methods to study transcriptomics. In the field of altered gravity research, both methods are frequently used. However, the generation of these data sets is difficult and time-consuming and therefore the number of available data sets in this research field is limited. In this study, we investigated the comparability of microarray and RNA-Seq data and applied the results to a comparison of the transcriptomics dynamics between the hypergravity conditions during two real flight platforms and a centrifuge experiment to identify temporal adaptation processes. We performed a comparative study on an Affymetrix HTA2.0 microarray and a paired-end RNA-Seq data set originating from the same Jurkat T cell RNA samples from a short-term hypergravity experiment. The overall agreeability was high, with better sensitivity of the RNA-Seq analysis. The microarray data set showed weaknesses on the level of single upregulated genes, likely due to its normalization approach. On an aggregated level of biotypes, chromosomal distribution, and gene sets, both technologies performed equally well. The microarray showed better performance on the detection of altered gravity-related splicing events. We found that all initially altered transcripts fully adapted after 15 min to hypergravity and concluded that the altered gene expression response to hypergravity is transient and fully reversible. Based on the combined multiple-platform meta-analysis, we could demonstrate rapid transcriptional adaptation to hypergravity, the differential expression of the ATPase subunits ATP6V1A and ATP6V1D, and the cluster of differentiation (CD) molecules CD1E, CD2AP, CD46, CD47, CD53, CD69, CD96, CD164, and CD226 in hypergravity. We could experimentally demonstrate that it is possible to develop methodological evidence for the meta-analysis of individual data.

Improving the understanding of cytoneme-mediated morphogen gradients by in silico modeling.

Morphogen gradients are crucial for the development of organisms. The biochemical properties of many morphogens prevent their extracellular free diffusion, indicating the need of an active mechanism for transport. The involvement of filopodial structures (cytonemes) has been proposed for morphogen signaling. Here, we describe an in silico model based on the main general features of cytoneme-meditated gradient formation and its implementation into Cytomorph, an open software tool. We have tested the spatial and temporal adaptability of our model quantifying Hedgehog (Hh) gradient formation in two Drosophila tissues. Cytomorph is able to reproduce the gradient and explain the different scaling between the two epithelia. After experimental validation, we studied the predicted impact of a range of features such as length, size, density, dynamics and contact behavior of cytonemes on Hh morphogen distribution. Our results illustrate Cytomorph as an adaptive tool to test different morphogen gradients and to generate hypotheses that are difficult to study experimentally.

Environmental jolts and temporal adaptation in a local solar energy movement

Environmental jolts are unexpected external shocks of the institutional environment that disrupt actors and movement processes and trigger adaptative responses in them. A jolt represents a disconti...

Theory on The Vision-based Mechanisms of Subjective Time Within The Context of The Neural and Psychological Models of Time Perception

Temporal processing is crucial for interval, duration and motion discrimination, as well as the ability to order events. Humans process temporal information over a large scale ranging from microseconds to daily circadian rhythms. The basic questions in the time perception literature include whether timing is centralized or distributed in the brain and whether different time scales or modalities (such as sensory or motor) are processed by different neural mechanisms. In this review, focus will be on visual timing in the millisecond range and the underlying temporal mechanisms.The classical model of a supramodal centralised clock, in which scaling between real and apparent time is accomplished by a change in the arousal level, has been challenged by our evidence, following Johnston et al. (2006), that the apparent duration can be manipulated in a local region of visual field by adaptation to motion or flicker and that the effects of temporal frequency adaptation on perceived duration and perceived temporal frequency are dissociable. The relationship between time, motion and space supports the idea that time is an attribute of a visual stimulus like any other low level features such as color or motion, which we suggest may imply a time pathway in the brain. Keywords: Visual perception, time perception, visual brain

Adapting Footfall Rhythmicity to Auditory Perturbations Affects Resilience of Locomotor Behavior: A Proof-of-Concept Study.

For humans, the ability to effectively adapt footfall rhythm to perturbations is critical for stable locomotion. However, only limited information exists regarding how dynamic stability changes when individuals modify their footfall rhythm. In this study, we recorded 3D kinematic activity from 20 participants (13 males, 18–30 years old) during walking on a treadmill while synchronizing with an auditory metronome sequence individualized to their baseline walking characteristics. The sequence then included unexpected temporal perturbations in the beat intervals with the subjects required to adapt their footfall rhythm accordingly. Building on a novel approach to quantify resilience of locomotor behavior, this study found that, in response to auditory perturbation, the mean center of mass (COM) recovery time across all participants who showed deviation from steady state (N = 15) was 7.4 (8.9) s. Importantly, recovery of footfall synchronization with the metronome beats after perturbation was achieved prior (+3.4 [95.0% CI +0.1, +9.5] s) to the recovery of COM kinematics. These results highlight the scale of temporal adaptation to perturbations and provide implications for understanding regulation of rhythm and balance. Thus, our study extends the sensorimotor synchronization paradigm to include analysis of COM recovery time toward improving our understanding of an individual’s resilience to perturbations and potentially also their fall risk.

Variable Practice May Enhance Ball Catching Skills in Some but Not All Children With DCD

Children with DCD exhibit many motor issues including ball catching, which have not been addressed clinically. The purpose of this study was to examine if variable practice can improve one-handed catching performance of five boys with DCD with severe (M = 11.1 years, SD = .7) and moderate movement problems (M = 11. 7 years, SD = .9). Both groups attended 12 sessions, with 8 blocks of 10 attempts, across four different ball velocities. Children with moderate issues caught more balls at post- and transfer test, as compared to pre-test. Kinematic profiles showed that both groups exhibited stable configuration of the catching arm; however, only children with moderate issues increased (peak) velocity, degree of spatial adaptations, and extended the pre-programmed ballistic phase of the action. Thus, variable practice appeared to be effective for children with moderate issues but not those with severe problems. In line with VPH hypothesis, these improvements were due to strengthening of the schema responsible for spatial and temporal adaptations of the end effector.

Finite element solution of nonlocal Cahn–Hilliard equations with feedback control time step size adaptivity

AbstractIn this study, we evaluate the performance of feedback control‐based time step adaptivity schemes for the nonlocal Cahn–Hilliard equation derived from the Ohta–Kawasaki free energy functional. The temporal adaptivity scheme is recast under the linear feedback control theory equipped with an error estimation that extrapolates the solution obtained from an energy‐stable, fully implicit time marching scheme. We test three time step controllers with different properties: a simple Integral controller, a complete proportional‐integral‐derivative controller, and the PC11 predictive controller. We assess the performance of the adaptive schemes for the nonlocal Cahn–Hilliard equation in terms of the number of time steps required for the complete simulation and the computational effort measured by the required number of nonlinear and linear solver iterations. We also present numerical evidence of mass conservation and free energy decay for simulations with the three different time step controllers. The PC11 predictive controller is the best in all three‐dimensional test cases.

A multiresolution local-timestepping scheme for particle–laden multiphase flow simulations using a level-set and point-particle approach

We present a novel storage-and-access approach for Lagrangian particles in a multiresolution local-timestepping framework for multiphase flow simulations. The proposed method applies a block-particle mapping strategy for efficient access of all particles on a specific refinement level while traversing through the multiresolution tree. This allows for extending the local timestepping algorithm with its refinement level-dependent timestep sizes to the evolution of particles, which results in significant speed-up in comparison to standard timestepping. For multi-scale multiphase flow simulations, the particle model is combined with a level-set based multiphase model on a Cartesian grid. To maintain robustness of fluid-state interpolation for particles near the level set-based fluid–fluid interface, WENO-based interpolation is applied which includes both real- and ghost-fluid cells. This enforces the sharp interface property also for interpolated fluid states, and suppresses spurious oscillations in the event of discontinuities.We validate the particle model with a one-dimensional simulation of a single particle in an air–helium shock tube for one-way coupling, and with two-dimensional simulations of a particle injected in a quiescent domain for the feedback force. Simulations of two-dimensional aerodynamic fragmentation in shear-induced entrainment and Rayleigh–Taylor piercing regimes use Lagrangian particles as sub-grid scale representation of small droplets post-breakup. Finally, three-dimensional massively-parallel simulations of single- and triple-bubble collapse near a wall coated with free-floating particles are presented. The particle cleaning radius of the single-bubble setup agrees reasonably well with experimental reference data. These simulations consider 106 particles and an Eulerian grid with effectively 1012 finite-volume cells at compression rates of more than 90% for the particulate phase. This underlines the advantageous effect of embedding the particles in the multiresolution tree with its spatial and temporal adaptivity, which is necessary for performing such large scale simulations efficiently.

Religion in times of crisis: Innovative lay responses and temporal-spatial reconfigurations of temple rituals in COVID-19 China

The COVID-19 pandemic has brought about massive changes in religious landscapes across the world. Recent research has focused on whether religions create problems or are sources of solution or support in these extraordinary times. Although some studies document religious leaders’ and institutions’ innovative responses to preserve ritual practices and foster members’ sense of belonging, they fail to highlight lay practitioners’ bottom-up religious transformations. Noting this, this article draws on the case of Lufeng city in south China to examine how local residents inventively reconfigured the temporal-spatiality of their ritual practices during temple lock-downs. Through an ethnographic-style exploration, we reveal multi-faceted spatial changes in the ritual performance, including the reconfiguration of home spaces, the performance of worship practices outside temple doors and the mobilization of digital spaces of communication to accumulate good fortune. Apart from these spatial strategies, local ritual transformation also produces temporal adaptations. Through these temporal-spatial reconfigurations, local residents innovatively cope with new social circumstances and articulate religion’s continual significance. This study foregrounds an agentive and flexible understanding of religion in times of crisis.

Cold-induction of afadin in brown fat supports its thermogenic capacity

The profound energy-expending nature of brown adipose tissue (BAT) thermogenesis makes it an attractive target tissue to combat obesity-associated metabolic disorders. While cold exposure is the strongest inducer of BAT activity, the temporal mechanisms tuning BAT adaptation during this activation process are incompletely understood. Here we show that the scaffold protein Afadin is dynamically regulated by cold in BAT, and participates in cold acclimation. Cold exposure acutely increases Afadin protein levels and its phosphorylation in BAT. Knockdown of Afadin in brown pre-adipocytes does not alter adipogenesis but restricts β3-adrenegic induction of thermogenic genes expression and HSL phosphorylation in mature brown adipocytes. Consistent with a defect in thermogenesis, an impaired cold tolerance was observed in fat-specific Afadin knockout mice. However, while Afadin depletion led to reduced Ucp1 mRNA induction by cold, stimulation of Ucp1 protein was conserved. Transcriptomic analysis revealed that fat-specific ablation of Afadin led to decreased functional enrichment of gene sets controlling essential metabolic functions at thermoneutrality in BAT, whereas it led to an altered reprogramming in response to cold, with enhanced enrichment of different pathways related to metabolism and remodeling. Collectively, we demonstrate a role for Afadin in supporting the adrenergic response in brown adipocytes and BAT function.

Light at Night and Disrupted Circadian Rhythms Alter Physiology and Behavior.

Life on earth has evolved during the past several billion years under relatively bright days and dark nights. Virtually all organisms on the planet display an internal representation of the solar days in the form of circadian rhythms driven by biological clocks. Nearly every aspect of physiology and behavior is mediated by these internal clocks. The widespread adoption of electric lights during the past century has exposed animals, including humans, to significant light at night (LAN) for the first time in our evolutionary history. Importantly, endogenous circadian clocks depend on light for synchronization with the external daily environment. Thus, LAN can derange temporal adaptations. Indeed, disruption of natural light-dark cycles results in several physiological and behavioral changes. In this review, we highlight recent evidence demonstrating how LAN exposure can have serious implications for adaptive physiology and behavior, including immune, endocrine, and metabolic function, as well as reproductive, foraging, and migratory behavior. Lastly, strategies to mitigate the consequences of LAN on behavior and physiology will be considered.

A PCR-RFLP method for genotyping of inversion 2Rc in Anopheles coluzzii

BackgroundGenotyping of polymorphic chromosomal inversions in malaria vectors such as An. coluzzii Coetzee & Wilkerson is important, both because they cause cryptic population structure that can mislead vector analysis and control and because they influence epidemiologically relevant eco-phenotypes. The conventional cytogenetic method of genotyping is an impediment because it is labor intensive, requires specialized training, and can be applied only to one gender and developmental stage. Here, we circumvent these limitations by developing a simple and rapid molecular method of genotyping inversion 2Rc in An. coluzzii that is both economical and field-friendly. This inversion is strongly implicated in temporal and spatial adaptations to climatic and ecological variation, particularly aridity.MethodsUsing a set of tag single-nucleotide polymorphisms (SNPs) strongly correlated with inversion orientation, we identified those that overlapped restriction enzyme recognition sites and developed four polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) assays that distinguish alternative allelic states at the tag SNPs. We assessed the performance of these assays using mosquito population samples from Burkina Faso that had been cytogenetically karyotyped as well as genotyped, using two complementary high-throughput molecular methods based on tag SNPs. Further validation was performed using mosquito population samples from additional West African (Benin, Mali, Senegal) and Central African (Cameroon) countries.ResultsOf four assays tested, two were concordant with the 2Rc cytogenetic karyotype > 90% of the time in all samples. We recommend that these two assays be employed in tandem for reliable genotyping. By accepting only those genotypic assignments where both assays agree, > 99% of assignments are expected to be accurate.ConclusionsWe have developed tandem PCR-RFLP assays for the accurate genotyping of inversion 2Rc in An. coluzzii. Because this approach is simple, inexpensive, and requires only basic molecular biology equipment, it is widely accessible. These provide a crucial tool for probing the molecular basis of eco-phenotypes relevant to malaria epidemiology and vector control.Graphical

Effects of Obesity on Adaptation Transfer from Treadmill to Over-Ground Walking

Discerning whether individuals with obesity transfer walking adaptation from treadmill to over-ground walking is critical to advancing our understanding of walking adaptation and its usefulness in rehabilitating obese populations. We examined whether the aftereffects following split-belt treadmill adaptation transferred to over-ground walking in adults with normal-weight body mass index (BMI) and obese BMI. Nineteen young adults with obesity and 19 age-matched adults with normal weight walked on flat ground at their preferred speed before and after walking on a treadmill with tied belts (preferred speed) and with the split-belt at their preferred speed and at a speed 50% slower than their preferred speed. The adaptation and aftereffects in step length and double-limb support time symmetry were calculated. We found that the amount of temporal adaptation was similar for adults with obesity and with normal weight (p > 0.05). However, adults with obesity showed greater asymmetry for double-limb support time following split-belt treadmill walking compared to adults with normal weight (p < 0.05). Furthermore, the transfer of asymmetry for double-limb support time from the treadmill to over-ground walking was less in adults with obesity than in adults with normal weight (p < 0.05). The transfer of adapted gait following split-belt treadmill walking provides insight into how atypical walking patterns in individuals with obesity could be remediated using long-term gait training.

A New Deep Dual Temporal Domain Adaptation Method for Online Detection of Bearings Early Fault.

With the quick development of sensor technology in recent years, online detection of early fault without system halt has received much attention in the field of bearing prognostics and health management. While lacking representative samples of the online data, one can try to adapt the previously-learned detection rule to the online detection task instead of training a new rule merely using online data. As one may come across a change of the data distribution between offline and online working conditions, it is challenging to utilize the data from different working conditions to improve detection accuracy and robustness. To solve this problem, a new online detection method of bearing early fault is proposed in this paper based on deep transfer learning. The proposed method contains an offline stage and an online stage. In the offline stage, a new state assessment method is proposed to determine the period of the normal state and the degradation state for whole-life degradation sequences. Moreover, a new deep dual temporal domain adaptation (DTDA) model is proposed. By adopting a dual adaptation strategy on the time convolutional network and domain adversarial neural network, the DTDA model can effectively extract domain-invariant temporal feature representation. In the online stage, each sequentially-arrived data batch is directly fed into the trained DTDA model to recognize whether an early fault occurs. Furthermore, a health indicator of target bearing is also built based on the DTDA features to intuitively evaluate the detection results. Experiments are conducted on the IEEE Prognostics and Health Management (PHM) Challenge 2012 bearing dataset. The results show that, compared with nine state-of-the-art fault detection and diagnosis methods, the proposed method can get an earlier detection location and lower false alarm rate.

Spatiotemporal variation of soil moisture in Northern China based on climate change initiative data

AbstractIn view of the sparse, uneven distribution and poor data continuity of measured soil moisture sites in China and the lack of large‐scale research, the soil moisture data set of the European Space Agency (ESA) Climate Change Initiative (CCI) was applied to carry out spatial‐temporal variation analysis of soil moisture in five agricultural ecological zones in Northern China. The Pearson correlation coefficient and multiple‐component metric Kling–Gupta efficiency were used to verify the validity of remote sensing data and to analyze the temporal and spatial variation of soil moisture with the concept of temporal and spatial persistence. The ESA CCI remote sensing soil moisture data had good spatial and temporal adaptability for the whole year in the Huang‐Huai‐Hai region, in summer in Northeast China, in spring in Northwest China, in summer and autumn in the Loess Plateau, and in summer and autumn in the Inner Mongolian Plateau. The annual mean soil volume water content in Northern China from 1991 to 2016 was 0.06–0.39 m3 m−3. Spatially, soil moisture in Northern China has been gradually increasing from west to east. In this area, seasonally, soil moisture was the highest in summer, followed by autumn and then winter and spring. Northeast China, the Loess Plateau, and the Huang‐Huai‐Hai region are important grain‐producing areas in China. The soil moisture in these areas fluctuates widely with seasonal changes and shows an obvious drying trend.

TMJ Replacement Following Pseudoarthrosis of Condylar Neck Fracture With Dislocation of the Condylar Neck Within the Infra-Temporal Fossa

Study Design: Case Report Objective: To present a patient with long-standing TMJ dislocation and pseudoarthrosis in the temporal bone treated with orthognathic surgery and unilateral joint replacement. Method: The patient, a 52-year-old female, came to our department to treat facial asymmetry and oral rehabilitation. The patient reported early facial trauma at 7 years old showing partial edentoulism, dental occlusion class III and a 19 mm mandibular midline deviation. Cone beam computed tomography showed the left TMJ in long-standing dislocation into the fossa temporalis, creating a new articular fossa in the temporal bone and adaptation of the hard and soft tissue. Results: Orthognathic surgery and TMJ replacement using a patient-specific implant and dental rehabilitation were planned; surgery was performed with no complications, and the 1-year follow-up showed that this treatment was a good option for long-standing TMJ dislocation. Conclusion: The long-term TMJ dislocation can be successfully treated by TMJ replacement using a patient-specific implant to obtain facial balance and oral function and avoid relapse.

Prediction of Bearings Remaining Useful Life Across Working Conditions Based on Transfer Learning and Time Series Clustering

Recently, data-driven remaining useful life (RUL) prediction has become a promising tool in prognostics and health management for rolling bearings. In many actual applications, however, it is not easy to collect whole-life degradation data of bearings, while training with an insufficient amount of data would result in a biased RUL prediction model. If the monitoring data historically accumulated under different working conditions are introduced to facilitate model training, it probably tends to get inadequate prediction performance due to the violation of the precondition of independent and identical distribution ( ${i.i.d.}$ ). To solve this problem, a new bearing RUL prediction approach is proposed by utilizing the transfer learning strategy. First, a new time series clustering algorithm is proposed to exploit clusters of different degradation series. By integrating phase space warping and dynamic time warping, this algorithm is able to measure the similarity by using global degradation information and then get better clustering performance. Second, a new temporal domain adaptation method is proposed to obtain the pivot feature set of different bearings based on meta-degradation information which is represented by the principal curve of each cluster. Finally, support vector machine is run to establish the prediction model by means of these features, and RUL of the target bearing can be predicted via the same feature adaptation. A theoretical analysis is also provided to prove that the proposed approach has an upper bound of information loss in the transfer process. Experimental results on the IEEE PHM challenge 2012 dataset demonstrate the effectiveness of the proposed approach.