Feedback Mode Research Articles

AGN outflows and its variability

AbstractThe radiative mode of AGN feedback, operated through outflows, plays an essential role in the evolution of galaxies. Quasar outflows are detected as blue-shifted broad absorption lines in the UV/optical spectra of quasars. Thanks to the Sloan digital sky survey, 100,000 broad absorption line quasars are available now for ensemble statistical studies. This rich dataset has also enabled us to identify some peculiar cases of these sources. By quantifying the BAL fraction in radio-loud BAL quasars, our studies demonstrate a clear trend of increasing BAL fraction as the viewing angle approaches an edge-on orientation, favoring the orientation model of BAL quasars. Also, by contrasting the properties of BAL quasars with appearing and disappearing BAL troughs, our analysis suggests that the extreme variations in BAL troughs are driven by ionization changes.

Improving lexical retrieval with LingoTalk: an app-based, self-administered treatment for clients with aphasia

IntroductionLingoTalk is a German speech-language app designed to enhance lexical retrieval in individuals with aphasia. It incorporates automatic speech recognition (ASR) to provide therapist-independent feedback. The execution and effectiveness of a self-administered intervention with LingoTalk was explored in a case series study.MethodsThree individuals with chronic aphasia participated in a highly individualized, supervised self-administered intervention lasting 3 weeks. The LingoTalk app closely monitored the frequency, intensity and progress of the intervention. Treatment efficacy was assessed using a multiple baseline design, examining both item-specific treatment effects and generalization to untreated items, an untreated task, and spontaneous speech.ResultsAll participants successfully completed the intervention with LingoTalk, although one participant was not able to use the ASR feature. None of the participants fully adhered to the treatment protocol. All participants demonstrated significant and sustained improvement in the naming of practiced items, although there was limited evidence of generalization. Additionally, there was a slight reduction in word-finding difficulties during spontaneous speech.DiscussionThis small-scale study indicates that self-administered intervention with LingoTalk can improve oral naming of treated items. Thus, it has the potential to complement face-to-face speech-language therapy, such as within in a “flipped speech room” approach. The choice of feedback mode is discussed. Transparent progress monitoring of the intervention appears to positively influence patients' motivation.

Dialogic feedback in online teaching

Effective feedback requires a dynamic two-way process in which both teachers and students engage actively in dialogue. Online teaching has been widely adopted in education since COVID-19 pandemic; yet limited studies have explored the implications for dialogic feedback. This paper presents a study that seeks to identify challenges that teachers face when facilitating dialogic feedback in online teaching and explore how different feedback modes may enhance or hinder dialogic feedback. Based on findings of interviews with 16 in-service and pre-service teachers from the UK and Australia, we suggest that teacher education needs to highlight the development of student feedback literacy, the relational aspect of feedback, and pedagogical strategies to creative use of learning technologies for feedback.

Augmented feedback modes during functional grasp training with an intelligent glove and virtual reality for persons with traumatic brain injury

Augmented feedback modes during functional grasp training with an intelligent glove and virtual reality for persons with traumatic brain injury

Novel dynamic method based on CV-SECM and SWV-SECM for the in situ chemical imaging of reactive metal surfaces undergoing corrosion and corrosion inhibition illustrated with the case of copper corrosion inhibition by benzotriazole

A novel dynamic method for the chemical imaging of actively corroding metal surfaces using scanning electrochemical microscopy (SECM) is proposed by using CV-SECM and SWV-SECM. This consists of an adequate coupling of a repetitive voltammetric operation at the SECM tip while conducting the rastering routine for scanning a reactive copper surface, as well as its inhibition by benzotriazole. In this method, gold microelectrodes are employed as SECM tips, and therefore their electrochemical behaviour towards collection and redissolution of Cu2+ ions from synthetic solutions containing Cu2+ ions. Next, the dynamic application of voltammetric methods for the collection and stripping of copper on the Au probes while mapping copper surfaces was investigated. The proof of concept first involved continuous cyclic voltammetry (CV-SECM) in an acidified NaCl solution, in terms of Cu2+ dissolution and surface redox activity (with SECM in the feedback mode). Then, square wave voltammetry (SWV-SECM) was used to detect small copper dissolution from corroding and inhibitor-protected metal surfaces. The results are consistent with a heterogeneous nature of copper degradation and the development of protective films and passive layers.

Winds versus jets: a comparison between black hole feedback modes in simulations of idealized galaxy groups and clusters

ABSTRACT Using the SWIFT simulation code, we compare the effects of different forms of active galactic nuclei (AGNs) feedback in idealized galaxy groups and clusters. We first present a physically motivated model of black hole (BH) spin evolution and a numerical implementation of thermal isotropic feedback (representing the effects of energy-driven winds) and collimated kinetic jets that they launch at different accretion rates. We find that kinetic jet feedback is more efficient at quenching star formation in the brightest cluster galaxies (BCGs) than thermal isotropic feedback, while simultaneously yielding cooler cores in the intracluster medium (ICM). A hybrid model with both types of AGN feedback yields moderate star formation rates, while having the coolest cores. We then consider a simplified implementation of AGN feedback by fixing the feedback efficiencies and the jet direction, finding that the same general conclusions hold. We vary the feedback energetics (the kick velocity and the heating temperature), the fixed efficiencies and the type of energy (kinetic versus thermal) in both the isotropic and the jet case. The isotropic case is largely insensitive to these variations. On the other hand, jet feedback must be kinetic in order to be efficient at quenching. We also find that it is much more sensitive to the choice of energy per feedback event (the jet velocity), as well as the efficiency. The former indicates that jet velocities need to be carefully chosen in cosmological simulations, while the latter motivates the use of BH spin evolution models.

An Exploration of AGN and Stellar Feedback Effects in the Intergalactic Medium via the Low-redshift Lyα Forest

We explore the role of galactic feedback on the low-redshift Lyα (Lyα) forest (z ≲ 2) statistics and its potential to alter the thermal state of the intergalactic medium. Using the Cosmology and Astrophysics with Machine Learning Simulations (CAMELS) suite, we explore variations of the AGN and stellar feedback models in the IllustrisTNG and Simba subgrid models. We find that both AGN and stellar feedback in Simba play a role in setting the Lyα forest column density distribution function (CDD) and the Doppler width (b-value) distribution. The Simba AGN jet feedback mode is able to efficiently transport energy out to the diffuse IGM, causing changes in the shape and normalization of the CDD and a broadening of the b-value distribution. We find that stellar feedback plays a prominent role in regulating supermassive black hole growth and feedback, highlighting the importance of constraining stellar and AGN feedback simultaneously. In IllustrisTNG, the AGN feedback variations explored in CAMELS do not affect the Lyα forest, but varying the stellar feedback model does produce subtle changes. Our results imply that the low-z Lyα forest can be sensitive to changes in the ultraviolet background, stellar and black hole feedback, and that AGN jet feedback in particular can have a strong effect on the thermal state of the IGM.

Fibroblast growth factor 21 alleviates unilateral ureteral obstruction-induced renal fibrosis by inhibiting Wnt/β-catenin signaling pathway

Fibroblast growth factor 21 (FGF21) is a key regulator of energy metabolism. Recent studies suggested that serum FGF21 levels increase with declining renal function. However, the link between FGF21 and kidney diseases and the direct effect of FGF21 in renal fibrosis remains unclear. In this study, FGF21 was upregulated in unilateral ureteral obstruction (UUO)-induced renal fibrosis and cellular fibrosis induced by transforming growth factor-β, and renal expression of FGF21 was positively correlated with fibrosis markers. Additionally, FGF21 was regulated by Wnt/β-catenin signaling pathway. The knockdown and overexpression of FGF21 in mouse tubular epithelial cells demonstrated that FGF21 alleviates renal fibrosis by inhibiting the Wnt/β-catenin signaling pathway. To investigate the effect of FGF21 on renal fibrosis in vivo, we established an overexpression model by injecting the plasmid in mice and found that FGF21 overexpression relieved UUO-induced renal fibrosis and renal inflammatory response. Taken together, FGF21 is upregulated with the activation of Wnt/β-catenin signaling pathway and alleviates renal fibrosis by inhibiting the activation of Wnt/β-catenin signaling pathway in a negative feedback mode. These results provide a new understanding for the source of elevated serum FGF21 in patients with chronic kidney disease and prove that FGF21 is a direct inhibitor of the progression of renal fibrosis, thus providing novel therapeutic intervention insights for renal fibrosis.

COF-Coated Microelectrode for Space-Confined Electrochemical Sensing of Dopamine in Parkinson's Disease Model Mouse Brain.

Parkinson's disease (PD) is a progressive neurodegenerative disorder causing the loss of dopaminergic neurons in the substantia nigra and the drastic depletion of dopamine (DA) in the striatum; thus, DA can act as a marker for PD diagnosis and therapeutic evaluation. However, detecting DA in the brain is not easy because of its low concentration and difficulty in sampling. In this work, we report the fabrication of a covalent organic framework (COF)-modified carbon fiber microelectrode (cCFE) that enables the real-time detection of DA in the mouse brain thanks to the outstanding antibiofouling and antichemical fouling ability, excellent analytical selectivity, and sensitivity offered by the COF modification. In particular, the COF can inhibit the polymerization of DA on the electrode (namely, chemical fouling) by spatially confining the molecular conformation and electrochemical oxidation of DA. The cCFE can stably and continuously work in the mouse brain to detect DA and monitor the variation of its concentration. Furthermore, it was combined with levodopa administration to devise a closed-loop feedback mode for PD diagnosis and therapy, in which the cCFE real-time monitors the concentration of DA in the PD model mouse brain to instruct the dose and injection time of levodopa, allowing a customized medication to improve therapeutic efficacy and meanwhile avoid adverse side effects. This work demonstrates the fascinating properties of a COF in fabricating electrochemical sensors for in vivo bioanalysis. We believe that the COF with structural tunability and diversity will offer enormous promise for selective detection of neurotransmitters in the brain.

Multimodality in language education: implications of a multimodal affective perspective in foreign language teaching.

Foreign language learners often encounter various emotional challenges within academic environments, which can hinder their progress in developing literacy skills. Effective language instruction should encompass teaching approaches that acknowledge the emotional requirements of students. To address this need, we propose a multimodal affective methodology designed to evaluate emotions in foreign language education scenarios. This methodology also holds the potential to elucidate the pedagogic contributions of various emotional variables to academic outcomes. Our study focuses on German as a foreign language (GFL) learning and utilizes it as an example to investigate ways to improve writing proficiency. The study explores the effects of integrating multimodal corrective feedback (MCF) into academic writing exercises. We delve into suitable modalities for analyzing emotions in academic writing practices. Furthermore, we investigate how the choice of corrective feedback mode intricately influences the nature of feedback itself and subsequently influences students' emotional responses. Through a comprehensive exploration of the interplay between distinct modes of delivering feedback and their impacts on learners' engagement, this investigation strives to decode the intricate dynamics of emotions that underlie language acquisition. With these insights, the study discusses how teachers can enhance their teaching strategies by combining changes in learners' emotional states and providing emotional support.

The Estill Voice Model: A paradigm for voice training and treatment

For over 40 years, the Estill Voice Model (EVM) has defined voice quality according to movement of anatomy and physiology. EVM addresses the daunting degrees of freedom issue in voice motor control by isolating Craft of voice production from Artistry and Performance Metaphysics. The EVM proposes an integrated implicit-explicit approach for voice motor learning that flows through all training and therapy protocols. Implicit instructions include auditory-perceptual prompts (e.g., quack like a duck to produce “twang”) and explicit prompts train physiologic conditions of the vocal anatomy correlated with the voice quality (e.g., narrow your aryepiglottic sphincter to produce “twang”). Estill exercises address power, source, and filter properties of voice production, and include narrowing the aryepiglottic sphincter for “ring” in opera and belt and for increased power in hypofunctional voices, and varying vocal fold mass for register shifts and optimizing contact for hyperfunctional voices. Patients learn to feel, see, and hear the voice via multiple feedback modes including hand gestures, magnitude estimation of bodily kinesthetic effort, visual acoustic cues in real-time spectral analysis programs. This presentation will highlight objective measurement science and clinical evidence for using Estill exercises in treatment for all voices, from the novice speaker to the expert performer.

Haptic sensation-based scanning probe microscopy: Exploring perceived forces for optimal intuition-driven control

We demonstrate a cryogenic scanning probe microscope (SPM) that has been modified to be controlled with a haptic device, such that the operator can ‘feel’ the surface of a sample under investigation. This system allows for direct tactile sensation of the atoms in and on top of a crystal, and allows the operator to perceive, by using different SPM modalities, sensations that are representative of the relevant atomic forces and tunneling processes controlling the SPM. In particular, we operate the microscope in modes of (1) conventional STM feedback, (2) energy-dependent electron density imaging, (3) q-plus AFM frequency shift based force sensing, and (4) atomic manipulation/sliding. We also use software to modify the haptic feedback sensation to mimic different interatomic forces, including covalent bonding, Coulomb repulsion, Van der Waals repulsion and a full Lennard-Jones potential. This manner of SPM control creates new opportunities for human-based intuition scanning, and also acts as a novel educational tool to aid in understanding materials at an atomic level.

Joint Moment Responses to Different Modes of Augmented Visual Feedback of Joint Kinematics during Two-Legged Squat Training

This study examined the effects of different modes of augmented visual feedback of joint kinematics on the emerging joint moment patterns during the two-legged squat maneuver. Training with augmented visual feedback supports improved kinematic performance of maneuvers related to sports or daily activities. Despite being representative of intrinsic motor actions, joint moments are not traditionally evaluated with kinematic feedback training. Furthermore, stabilizing joint moment patterns with physical training is beneficial to rehabilitating joint-level function (e.g., targeted strengthening and conditioning of muscles articulating that joint). Participants were presented with different modes of augmented visual feedback to track a target squat-motion trajectory. The feedback modes varied along features of complexity (i.e., number of segment trajectories shown) and body representation (i.e., trajectories shown as sinusoids versus dynamic stick-figure avatars). Our results indicated that mean values and variability (trial-to-trial standard deviations) of joint moments are significantly (p < 0.05) altered depending on the visual feedback features being applied, the specific joint (ankle, knee, hip), and the squat movement phase (early, middle, or late time window). This study should incentivize more optimal delivery of visual guidance during rehabilitative training with computerized interfaces (e.g., virtual reality).

Filtered optical feedback modes effect on quantum-dot laser behavior

Filtered optical feedback modes effect on quantum-dot laser behavior

On the dominant role of wind in the quasar feedback mode in the late-stage evolution of massive elliptical galaxies

ABSTRACT In this paper, we investigate the role of active galactic nucleus (AGN) feedback on the late-stage evolution of elliptical galaxies by performing high-resolution hydrodynamical simulation in the MACER framework. By comparing models that take into account different feedback mechanisms, namely AGN and stellar feedback, we find that AGN feedback is crucial in keeping the black hole in a low accretion state and suppressing the star formation. We then compare the energy from AGN radiation and wind deposited in the galaxy and find that only wind can compensate for the radiative cooling of the gas in the galaxy. Further, we investigate which plays the dominant role, the wind from the cold (quasar) or hot (radio) feedback modes, by examining the cumulative energy output and impact area to which the wind can heat the interstellar medium and suppress star formation. Our results indicate that first, although AGN spends most of its time in hot (radio) mode, the cumulative energy output is dominated by the outburst of the cold (quasar) mode. Second, only the impact area of the cold-mode wind is large enough to heat the gas in the halo, while the hot-mode wind is not. Additionally, the cold-mode wind is capable of sweeping up the material from stellar mass-loss. These results indicate the dominant role of cold-mode wind. The limitations of our model, including the absence of jet feedback, are discussed.

An Analog Game-Based Intervention and a Playability Analysis in the Elderly - A Pilot Study

Introduction: Gamed-based interventions (GBI) in old people is an interesting topic for aging-well purposes, however, few studies exist focused on the assessment of multimodal interactive experience (emotions, skills, engagement, etc), and most of them used digital games. Therefore, validation of analog GBIs, when implemented in the geriatric field, should be completed with a playability analysis. Aim: To characterise a multicomponent playability analysis, considering (i) emotional state changes, and (ii) the perceived experience during the implementation of an analog gamed-based short-term intervention in the institutionalized elderly person. Method: A pre and post-test study was conducted during four weeks of intervention through an analogue game. Participants were elderly people institutionalised in a Residential Home for the Elderly in the central region of Portugal. Playability is assessed before and after the sessions with analogue games, using the Visual Analogue Scale (VAS) (0-10) of emotions and a questionnaire about participants’ perceptions of game-based experience. Results: Thirteen elderly people (9 women/4 men) with a mean age of 80±9.32 years participated in the study. A total of 48 states of tiredness/excitement, calmness/anxiety, and sadness/joy were recorded: 44,4% of participants increased their level of excitement; 66,7% decreased their level of excitement. The serious aims of the game were well perceived while maintaining the perception of the playful and fun character. Conclusion: The positive emotional changes in the elderly might be a sign of self-perceived novelty and challenge in the game. A good perception of the serious purpose of the game is associated with a positive emotional state, which encourages the adoption of proficiency feedback mode in the game. This pilot study was a relevant contribution to the continuing progression of playability analysis in elderly therapeutic contexts.

Cosmological Simulations of Galaxy Groups and Clusters. III. Constraining Quasar Feedback Models with the Atacama Large Millimeter Array

The thermal Sunyaev–Zeldovich (SZ) effect serves as a direct potential probe of the energetic outflows from quasars that are responsible for heating the intergalactic medium. In this work, we use the GIZMO meshless finite mass hydrodynamic cosmological simulation SIMBA, which includes different prescriptions for quasar feedback, to compute the SZ effect arising from different feedback modes. From these theoretical simulations, we perform mock observations of the Atacama Large Millimeter Array (ALMA) in four bands (320, 135, 100, and 42 GHz) to characterize the feasibility of direct detection of the quasar SZ signal. Our results show that for all the systems we get an enhancement of the SZ signal, when there is radiative feedback, while the signal gets suppressed when the jet mode of feedback is introduced in the simulations. Our mock ALMA maps reveal that, with the current prescription of jet feedback, the signal goes below the detection threshold of ALMA. We also find that the signal is higher for high redshift systems, making it possible for ALMA and cross SZ-X-ray studies to disentangle the varying modes of quasar feedback and their relative importance in the cosmological context.

Reconciling the magnetic field in central disc galaxies with the dynamical mass using the cosmological simulations

ABSTRACT The Universe is pervaded by magnetic fields in different scales, although for simplicity, they are ignored in most cosmological simulations. In this paper, we use the TNG50, which is a large cosmological galaxy formation simulation that incorporates magnetic fields with an unprecedented resolution. We study the correlation of the magnetic field with various galaxy properties such as the total, stellar, and gaseous mass, circular velocity, size, and star formation rate. We find a linear correlation between the average magnetic field pervading the disc of galaxies in relative isolation and their circular velocities. In addition, we observed that in this sample the average magnetic field in the disc is correlated with the total mass as $\overline{B}\sim M_{\mathrm{tot, R_{\star }}}^{0.2}$. We also find that the massive galaxies with active wind-driven black hole feedback, do not follow this trend, as their magnetic field is substantially affected by this feedback mode in the TNG50 simulation. We show that the correlation of the magnetic field with the star formation rate is a little weaker than the circular velocity. Moreover, we compare the magnetic field components of the above sample with a compiled observational sample of non-cluster non-interacting nearby galaxies. Similar to the observation, we find a coupling between the ordered magnetic field and the circular velocity of the flat part of the rotation curve in the simulation, although contrary to the observation, the ordered component is dominant in the simulation.

Supermassive black holes in merger-free galaxies have higher spins which are preferentially aligned with their host galaxy

ABSTRACT Here, we use the Horizon–active galactic nucleus (AGN) simulation to test whether the spins of supermassive black hole (SMBH) in merger-free galaxies are higher. We select samples using an observationally motivated bulge-to-total mass ratio of <0.1, along with two simulation-motivated thresholds selecting galaxies which have not undergone a galaxy merger since z = 2, and those SMBHs with $\lt 10~{{\ \rm per\ cent}}$ of their mass due to SMBH mergers. We find higher spins (>5σ) in all three sample compared to the rest of the population. In addition, we find that SMBHs with their growth dominated by BH mergers following galaxy mergers are less likely to be aligned with their galaxy spin than those that have grown through accretion in the absence of galaxy mergers (3.4σ). We discuss the implications this has for the impact of active galactic nucleus (AGN) feedback, finding that merger-free SMBHs spend on average 91 per cent of their lifetimes since z = 2 in a radio mode of feedback (88 per cent for merger-dominated galaxies). Given that previous observational and theoretical works have concluded that merger-free processes dominate SMBH-galaxy co-evolution, our results suggest that this co-evolution could be regulated by radio mode AGN feedback.

Conductivity mapping of topographically complex surfaces using contact-mode carbon fibre in potentiometric SECM

In numerous scientific and engineering applications, it is imperative to study the reactivity of material surfaces at a microscopic level. Scanning electrochemical microscopy (SECM) is a prevalent technique utilized to investigate and probe the electrochemical properties of surfaces. However, due to the inherent dependence of SECM on the distance between the sample and tip, uneven samples can pose a challenge, resulting in inaccurate measurements and incomplete understanding of material behavior. In this paper, we propose a novel approach for resolving this issue using contact-mode carbon fiber electrodes in potentiometric mode. The methodology introduced in this study presents a progressive development over the conventional feedback mode in certain circumstances, as it is capable of monitoring sample conductivity independent of its topography. This paper exemplifies two specific cases involving a tilted and a rough surface. A comparative analysis of the results obtained using the conventional feedback mode and the proposed method was conducted to further validate its efficacy. The findings demonstrate that the proposed method is highly effective in studying tilted and rugged substrates.