Perception Threshold Research Articles

Phantom perception as a Bayesian inference problem: a pilot study.

Tinnitus is the perception of a continuous sound in the absence of an external source. Although the role of the auditory system is well investigated, there is a gap in how multisensory signals are integrated to produce a single percept in tinnitus. Here, we train participants to learn a new sensory environment by associating a cue with a target signal that varies in perceptual threshold. In the test phase, we present only the cue to see whether the person perceives an illusion of the target signal. We perform two separate experiments to observe the behavioral and electrophysiological responses to the learning and test phases in 1) healthy young adults and 2) people with continuous subjective tinnitus and matched control subjects. We observed that in both parts of the study the percentage of false alarms was negatively correlated with the 75% detection threshold. Additionally, the perception of an illusion goes together with increased evoked response potential in frontal regions of the brain. Furthermore, in patients with tinnitus, we observe no significant difference in behavioral or evoked response in the auditory paradigm, whereas patients with tinnitus were more likely to report false alarms along with increased evoked activity during the learning and test phases in the visual paradigm. This emphasizes the importance of integrity of sensory pathways in multisensory integration and how this process may be disrupted in people with tinnitus. Furthermore, the present study also presents preliminary data supporting evidence that tinnitus patients may be building stronger perceptual models, which needs future studies with a larger population to provide concrete evidence on.NEW & NOTEWORTHY Tinnitus is the continuous phantom perception of a ringing in the ears. Recently, it has been suggested that tinnitus may be a maladaptive inference of the brain to auditory anomalies, whether they are detected or undetected by an audiogram. The present study presents empirical evidence for this hypothesis by inducing an illusion in a sensory domain that is damaged (auditory) and one that is intact (visual). It also presents novel information about how people with tinnitus process multisensory stimuli in the audio-visual domain.

Structural and Functional Characteristics of the Oral Cavity Organs and Tissues in Workers of the Petrochemical Industry of the Republic of Uzbekistan.

Purpose: The aim of the study was to determine the dental status, level, and structure of dental diseases, as well as to identify some clinical and functional deviations in the organs and tissues of the oral cavity among workers in certain industrial enterprises. Methodology: A comprehensive dental examination was conducted on 1600 individuals, including 420 from the Fergana Oil Refinery Plant (FNPP - main group (MG)-1), 425 from the Almalyk Mining and Metallurgical Plant (AGMK - MG-2), and 605 from the Navoi Chemical Plant (NavCP - MG-3), as well as 150 patients as a control group (CG) who visited a dental clinic. Tooth sensitivity (TS), pain and discriminatory sensitivity (PS and DS) of the oral mucosa, taste perception threshold, and functional mobility of the taste receptors on the tongue, enamel resistance to caries, microhardness (MH) of enamel and dentin, and the condition of periodontal tissues and pH of mixed saliva were determined. The data obtained were processed using statistical methods. Findings: It was determined that the levels and relative weights of the main dental diseases among workers in the studied industries remain quite high; carious and non-carious lesions of the tooth hard tissues, deformation and defects of teeth and dental rows (18.5%), periodontal tissue diseases (74.7%), diseases of the oral mucosa - 38.7%; the need for prosthetics (58.4%) and other pathologies. Additionally, almost all clinical and functional indicators and local non-specific reactivity of the tissues of the oral cavity in workers were disrupted. Unique Contribution to Theory, Policy and Practice: The presence of the main dental diseases among those surveyed from the studied groups is quite high, with noted reductions in the excitability threshold of teeth, around tooth tissues and the oral mucosa, disruption of PS and DS of the oral mucosa, as well as deterioration of the condition of tooth hard tissues. Based on the obtained results, the authors suggest continuing in-depth scientific research with the aim of developing effective methods for the diagnosis and prevention of dental diseases among workers in these industries.

Perceptibility and acceptability of lightness difference of a single maxillary central incisor.

The aim of this study was to assess the lightness difference perceptibility and acceptability thresholds, for a single maxillary central incisor, and to investigate possible differences in these thresholds regarding the direction (+ΔL* vs. -ΔL*), the observer group (dentists vs. laypersons), and the gender and age of the observers. A series of images with varying lightness (L*), were created by altering the right maxillary central incisor of a male Caucasian, on a frontal view full-portrait image. Digital modification of one central incisor by 1 ΔL* unit resulted in 15 different images: one control, seven with increased and seven with decreased lightness. The images were presented in random order, on a digitally calibrated monitor, to 158 observers, grouped into 79 dentists, and 79 laypersons, who were asked to evaluate every image and answer whether they perceive a difference and if yes, whether they accept this difference. A multifactorial analysis of covariance was performed to analyze the perception and acceptance of any difference in the central incisors and to estimate the thresholds. The statistical significance level was α = 0.05. Overall, the magnitude of ΔL*, direction of ΔL*, observer group and age were each significant (p < 0.001), as was gender (p = 0.03). The effect of the magnitude of ΔL* interacted with its direction and the observer group (p = 0.045), and the effect of age interacted with the direction of ΔL*, and the gender and the group of the observers. Estimated 50%:50% perceptibility thresholds ranged from 0.1 to 2.7, and 50%:50% acceptability thresholds ranged from 2.3 to 4.5. Overall, dentists perceived lightness differences at lower magnitudes than laypersons; difference in lightness was perceived and accepted at lower magnitudes when the tooth become lighter instead of darker; and female observers perceived and accepted lightness differences at lower magnitudes compared to males. As age increased overall, differences of lightness were perceived and accepted at higher magnitudes. Perceptibility and acceptability of lightness differences of a single maxillary central incisor are affected by the magnitude and the direction of lightness change, as well as the gender, the age, and the type of the observers. Even small changes in lightness are perceivable; however, thresholds of perception and acceptance are dependent on the magnitude and the direction of change and are also dependent on the observer, with women, dentists and younger people perceiving and accepting changes at lower magnitudes of ΔL*.

A Design and Construction of the Vibration Perception Threshold Measurement Device for Diabetes

A Design and Construction of the Vibration Perception Threshold Measurement Device for Diabetes

A patterned vibrotactile method using envelope modulation with high resolution and low perceptual frequency

The virtual haptics is a crucial aspect of immersive virtual reality, extending the traditional experiences of sight and hearing. The vibration can provide direct normal vibration and friction reduction, making it a promising method to realize virtual haptics. However, the optimum perceptual threshold of skin for vibration is 100 Hz to 500 Hz, resulting in a too low vibrotactile resolution. The conflict between the low perceptual frequency and high resolution still remains challenges. In this paper, a low-frequency envelope wave methodology is proposed to realize the localized vibrotactile feedback. The high-frequency components are modulated into a low-frequency envelope waveform, which provides low-frequency perception and high resolution at the same time. Due to hardware limitations, the modes must be truncated and minimized as much as possible. This requirement conflicts with achieving localized vibration at arbitrary points and further implementing complex vibration patterns. Therefore, a modal optimization algorithm is proposed to solve the inverse problem. The modal participation coefficients is obtained, basing on the evaluation index that ensures the frequency of the envelope wave and the vibration pattern quality. The localized vibration patterns including multiple points, points of proportional amplitude, bar and circle are achieved with a resolution of 3 cm and a perception frequency of about 200 Hz. This method is expected to be applied to virtual reality, blind assistance, and other potential applications to enhance tactile interaction experiences.

Vestibular Function: A Hidden Harbinger of Human Hypoxia

The aim of this study was to evaluate the impact of hypoxia on the human vestibular system — the organs in our inner ear that sense head motion and gravity. The vestibular system contributes to self-motion perception, balance control, and several reflexive responses. Maintaining ideal vestibular sensation imposes a high metabolic load; consider that the human vestibular periphery has over 100,000 hairs cells requiring energy to maintain depolarization and roughly 40,000 peripheral neurons requiring energy to support an average firing rate of nearly 100 action potentials per second for each neuron. Consistent with this, a recent study concluded that the vestibular organs of old animals appear to be bordering on an energy crisis; such an energy crisis could result from inadequate O2 or inadequate fuel. To quantify vestibular impacts of reduced O2, vestibular function was quantified using self-motion perceptual thresholds. Specifically, we used standard forced-choice psychophysical methods to determine the smallest earth-vertical (i.e., upward/downward) translation that a seated human could reliably sense. To quantify blood oxygenation, we used a standard fingertip pulse oximeter. To manipulate blood oxygenation, we controlled the oxygen (O2) air content using a Reduced Oxygen Breathing Device (Environics). Our hypotheses were that: (1) human vestibular thresholds will increase with reduced blood oxygenation, and (2) vestibular degradation will monotonically increase as blood oxygenation decreases. All data were collected at Wright Patterson Air Force Base (elevation 823’). On different days, participants breathed air having O2 content of 20.9%, 15.4%, 14.3%, 12.9%, 11.8%, and 10.7% — chosen to simulate O2 content found at altitudes of 0’ (“baseline”), 8,000’, 10,000’, 12,500’, 15,000’, and 17,500’. Fifteen participants completed test sessions at 20.9% and 15.4% O2. Earth-vertical translation thresholds were quantified to be 23.5% greater when the oxygen content was 15.4% than at baseline (p=0.005, Wilcoxson Sign Rank Test, Z = -2.84). While all subjects were unable to complete all conditions, a second set of participants was invited to complete test sessions at 20.9%, 14.3%, 12.9%, 11.8%, and 10.7% O2. Thresholds increased as O2 content decreased. Subjects reported no spatial disorientation. We did not vary barometric pressure, but these results show that vestibular thresholds are both significantly and substantively impacted at simulated altitudes of 8,000’. This is noteworthy because it matches the cabin pressurization required in the US by the FAA for commercial flights. These results suggest that many of us who have flown in a commercial jet may have experienced degraded vestibular function. Behavioral impacts remain to be understood, but vestibular function does appear to be a harbinger of human hypoxia. Support provided by Offce of Navy Research via a Multidisciplinary University Research Initiative (MURI N00014-20-1-2163). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Thresholds and mechanisms of human magnetophosphene perception induced by low frequency sinusoidal magnetic fields

BackgroundVirtually everyone is exposed to power-frequency MF (50/60 Hz), inducing in our body electric fields and currents, potentially modulating brain function. MF-induced electric fields within the central nervous system can generate flickering visual perceptions (magnetophosphenes), which form the basis of international MF exposure guidelines and recommendations protecting workers and the general public. However, magnetophosphene perception thresholds were estimated 40 years ago in a small, unreplicated study with significant uncertainties and leaving open the question of the involved interaction site. MethodsWe used a stimulation modality termed transcranial alternating magnetic stimulation (tAMS), delivering in situ sinusoidal electric fields comparable to transcranial alternating current stimulation (tACS). Magnetophosphene perception was quantified in 81 volunteers exposed to MF (eye or occipital exposure) between 0 and 50 mT at frequencies of 20, 50, 60 and 100 Hz. ResultsReliable magnetophosphene perception was induced with tAMS without any scalp sensation, a major advantage as compared to tACS. Frequency-dependent thresholds were quantified using binary logistic regressions hence allowing to establish condition dependent probabilities of perception. Results support an interaction between induced current density and retinal rod cells. ConclusionBeyond fundamental and immediate implications for international safety guidelines, and for identifying the interaction site underlying phosphene perception (ubiquitous in tACS experiments), our results support exploring the potential of tAMS for the differential diagnosis of retinal disorders and neuromodulation therapy.

Pain management In Total Knee Arthroplasty: Which helps in better post-operative outcomes?

Background: Individuals exhibit variations in pain perception and pain threshold, and these differences exist between the right and left limbs, resulting in biases related to inter-cerebral pain variability and inter-patient pain variability. Currently, there is limited available data comparing adductor canal block (ACB) with femoral nerve block (FNB) in individuals who have undergone bilateral total knee arthroplasty (TKA). Methods: We conducted a prospective, non-randomized, controlled study involving patients scheduled for bilateral total knee arthroplasty (TKA) under central neuraxial anesthesia. Following surgery, patients received intermittent 12-hourly boluses of 15 mL ropivacaine 0.5% through two distinct peripheral nerve blocks (adductor canal block - ACB and femoral nerve block - FNB) in either of the lower limbs. The primary objective was to evaluate the postoperative Visual Analog Scale (VAS) score, while the secondary outcomes included the assessment of quadriceps muscle strength and the degree of flexion at the knee joint. Results: Out of the 70 patients evaluated for eligibility, 63 were enrolled, and 60 were included in the final analysis. Visual Analog Scale (VAS) scores after both blocks during periods of rest at 30 minutes, 6 hours, 12 hours, and 48 hours post-operatively did not exhibit any significant differences. However, VAS scores during rest at 24 hours and during exercise at 24 hours and 48 hours demonstrated a notable disparity. Furthermore, there was a significant difference in favour of adductor canal block (ACB) over femoral nerve block (FNB) regarding quadriceps muscle strength and the degree of knee flexion at 24 hours and 48 hours post-operatively. Conclusions: Adductor canal block (ACB) delivers comparable pain relief to femoral nerve block (FNB) both at rest and during passive exercise for up to 48 hours after surgery. ACB notably maintains the motor strength of quadriceps muscles when contrasted with FNB, and this preservation comes without introducing any additional complications.

Contemporary prevalence of diabetic neuropathies in individuals with type 1 and type 2 diabetes in a Danish tertiary outpatient clinic

BackgroundPopulation-based prevalence estimates of distal symmetric polyneuropathy (DPN) and diabetic autonomic neuropathy (DAN) are scares. Here we present neuropathy estimates and describe their overlap in a large cohort of people with type 1 and type 2 diabetes. MethodsIn a large population of outpatient participants, DPN was assessed using vibration perception threshold, sural nerve function, touch, pain and thermal sensation. Definite DPN was defined by the Toronto Consensus Criteria. Painful DPN was defined by Douleur Neuropathique 4 Questions. DAN measures were: cardiovascular reflex tests, electrochemical skin conductance, and gastroparesis cardinal symptom index. ResultsWe included 822 individuals with type 1 (mean age (±SD) 54 ± 16 years, median [IQR] diabetes duration 26 [15–40] years) and 899 with type 2 diabetes (mean age 67 ± 11 years, median diabetes duration 16 [11−22] years).Definite DPN was prevalent in 54 % and 68 %, and painful DPN was in 5 % and 15 % of type 1 and type 2 participants, respectively. The prevalence of DAN varied between 6 and 39 % for type 1 and 9–49 % for type 2 diabetes. DPN without other neuropathy was present in 45 % with T1D and 50 % with T2D. ConclusionThe prevalence of DPN and DAN was high. DPN and DAN co-existed in only 50 % of cases.

Frequency dependence of human thresholds: both perceptual and vestibuloocular reflex thresholds.

Although perceptual thresholds have been widely studied, vestibuloocular reflex (VOR) thresholds have received less attention, so the relationship between VOR and perceptual thresholds remains unclear. We compared the frequency dependence of human VOR thresholds to human perceptual thresholds for yaw head rotation in both upright ("yaw rotation") and supine ("yaw tilt") positions, using the same human subjects and motion device. VOR thresholds were generally a little smaller than perceptual thresholds. We also found that horizontal VOR thresholds for both yaw rotation about an Earth-vertical axis and yaw tilt (yaw rotation about an Earth-horizontal axis) were relatively constant across four frequencies (0.2, 0.5, 1, and 2 Hz), with little difference between yaw rotation and yaw tilt VOR thresholds. For yaw tilt stimuli, perceptual thresholds were slightly lower at the lowest frequency and nearly constant at all other (higher) frequencies. However, for yaw rotation, perceptual thresholds increased significantly at the lowest frequency (0.2 Hz). We conclude 1) that VOR thresholds were relatively constant across frequency for both yaw rotation and yaw tilt, 2) that the known contributions of velocity storage to the VOR likely yielded these VOR thresholds that were similar for yaw rotation and yaw tilt for all frequencies tested, and 3) that the integration of otolith and horizontal canal signals during yaw tilt when supine contributes to stable perceptual thresholds, especially relative to the low-frequency perceptual thresholds recorded during yaw rotation.NEW & NOTEWORTHY We describe for the first time that human VOR thresholds differ from human forced-choice perceptual thresholds, with the difference especially evident at frequencies below 0.5 Hz. We also report that VOR thresholds are relatively constant across frequency for both yaw rotation and yaw tilt. These findings are consistent with the idea that high-pass filtering in cortical pathways impacts cognitive decision-making.

Intra-individual consistency of vestibular perceptual thresholds.

Vestibular perceptual thresholds quantify sensory noise associated with reliable perception of small self-motions. Previous studies have identified substantial variation between even healthy individuals' thresholds. However, it remains unclear if or how an individual's vestibular threshold varies over repeated measures across various time scales (repeated measurements on the same day, across days, weeks, or months). Here, we assessed yaw rotation and roll tilt thresholds in four individuals and compared this intra-individual variability to inter-individual variability of thresholds measured across a large age-matched cohort each measured only once. For analysis, we performed simulations of threshold measurements where there was no underlying variability (or it was manipulated) to compare to that observed empirically. We found remarkable consistency in vestibular thresholds within individuals, for both yaw rotation and roll tilt; this contrasts with substantial inter-individual differences. Thus, we conclude that vestibular perceptual thresholds are an innate characteristic, which validates pooling measures across sessions and potentially serves as a stable clinical diagnostic and/or biomarker.

Salt Perception Threshold and Vascular Risk in Prehypertensive Women Compared to Normotensive and Hypertensive Women

Objectives: To evaluate and compare the Salt perception threshold and vascular stiffness in pre-hypertensive women with that of normotensive and hypertensive women. Materials and Methods: Study design – This was a cross-sectional study. A total of 440 adult females in the age group of 25–60 years from urban and rural areas were included in the study. After initial screening, the subjects were divided into three groups. Group I: Prehypertensive females; Group II: Hypertensive females; and Group III: Normotensive females. Salt perception threshold was determined by salt impregnated taste strips with sodium chloride at different concentrations. Vascular stiffness of the subjects was measured and compared using an oscillometric non-invasive arteriography. Results: The salt intake was higher by 2.1 g/day in Group I females and 5.6 g/day in Group II females when compared to Group III females. The salt detection threshold and SPT were higher significantly in pre-hypertensive females and much higher in hypertensive females compared to normotensive females. The mean values of brachial ankle pulse wave velocity (BaPWV) and carotid femoral pulse wave velocity (CFPWV) were found to be significantly higher in Group I females compared to normotensives. Conclusion: High SPT in prehypertensive females will lead to high consumption of salt to achieve taste satisfaction. A progressive reduction of salt in food is recommended in these females would significantly decrease the percent progression of pre-HTN to HTN decreasing the risk for cardiovascular morbidity.

Stimulus-dependent differences in cortical versus subcortical contributions to visual detection in mice

The primary visual cortex (V1) and the superior colliculus (SC) both occupy stations early in the processing of visual information. They have long been thought to perform distinct functions, with the V1 supporting the perception of visual features and the SC regulating orienting to visual inputs. However, growing evidence suggests that the SC supports the perception of many of the same visual features traditionally associated with the V1. To distinguish V1 and SC contributions to visual processing, it is critical to determine whether both areas causally contribute to the detection of specific visual stimuli. Here, mice reported changes in visual contrast or luminance near their perceptual threshold while white noise patterns of optogenetic stimulation were delivered to V1 or SC inhibitory neurons. We then performed a reverse correlation analysis on the optogenetic stimuli to estimate a neuronal-behavioral kernel (NBK), a moment-to-moment estimate of the impact of V1 or SC inhibition on stimulus detection. We show that the earliest moments of stimulus-evoked activity in the SC are critical for the detection of both luminance and contrast changes. Strikingly, there was a robust stimulus-aligned modulation in the V1 contrast-detection NBK but no sign of a comparable modulation for luminance detection. The data suggest that behavioral detection of visual contrast depends on both V1 and SC spiking, whereas mice preferentially use SC activity to detect changes in luminance. Electrophysiological recordings showed that neurons in both the SC and V1 responded strongly to both visual stimulus types, while the reverse correlation analysis reveals when these neuronal signals actually contribute to visually guided behaviors.

Guidelines to optimise the sensory detection of 2,4,6-trichloroanisole in neutral spirit and whisky

Why was the work done: Guidelines are required to optimise the sensory detection of musty/stale taints in alcoholic spirits caused by 2,4,6-trichloroanisole. Early detection of the taint is necessary as the low sensory threshold can result in significant quality issues and masking the musty/stale off-note through blending is difficult. How was the work done: The standard industry practice for ‘nosing’ is to dilute samples of spirit to 20% ABV to prevent sensory fatigue. It is not known if 20% ABV is the optimal concentration for detecting 2,4,6-trichloroanisole. In this study, the effects of ethanol concentration on the detection of the taint were evaluated using a sensory panel and gas chromatography-mass spectroscopy. The efficacy of nosing versus tasting to detect 2,4,6-trichloroanisole was investigated at different dilutions of distilled spirits. Further, the stability of this off-note at 20% ABV was determined to assess if the taint could be detected by nosing over a working day. Finally, the serving temperature of the sample was assessed in the sensory perception of the taint. What are the main findings: The recommendations to optimise the sensory detection of 2,4,6-trichloroanisole in spirit samples are (i) nose samples at 20% ABV, (ii) as soon as possible after dilution conduct sensory tests and (iii) chill the sample. Why is the work important: The limits of detection for conventional solid phase microextraction with gas chromatography-mass spectroscopy are typically above the threshold of human perception. Therefore, the industry needs to maximise the detection by sensory panellists of contaminated whisky samples to ensure the product does not go to market so as to avoid any reputational damage.

Gastrointestinal symptom burden in diabetic autonomic and peripheral neuropathy – A Danes cohort study

ObjectiveWe investigated associations between gastrointestinal symptoms - evaluated as a combined weighted symptom score (CWSS) – Diabetic autonomic neuropathy (DAN), and distal symmetrical polyneuropathy (DSPN) in type 1 and type 2 diabetes. Research design and methodsCross-sectional study in a tertiary outpatient clinic. CWSS was calculated based on questionnaires: gastroparesis composite symptom index (GCSI) and gastrointestinal symptom rating score (GSRS). DAN and DSPN were addressed using the composite autonomic symptom score 31 (COMPASS-31) questionnaire, cardiac autonomic reflex tests (CARTs), electrochemical skin conductance (ESC), vibration perception threshold (VPT), Michigan Neuropathy Screening Instrument (MNSI), pain- and thermal sensation.Analyses were adjusted for age, sex, diabetes duration, smoking, LDL-cholesterol, HbA1C and systolic blood pressure. Type 1 and type 2 diabetes were evaluated separately. ResultsWe included 566 with type 1 diabetes and 377 with type 2 diabetes. Mean ± SD age was 58 ± 15 years and 565 (59.9 %) were women. A high CWSS was present in 143 (25 %) with type 1 and 142 (38 %) with type 2 diabetes. The odds of DAN by COMPASS-31 (p < 0.001) were higher in the high score group. For type 1 diabetes, odds of cardiac autonomic neuropathy were higher in the high CWSS group. The odds of DSPN by VPT and MNSI in type 1 diabetes, and by ESC, VPT and pain sensation in type 2 diabetes were higher in the high CWSS group. ConclusionsA high symptom score was associated with neuropathy by COMPASS-31 and vibration perception. Gastrointestinal symptom burden associated inconsistently with other neuropathy tests between diabetes types.

Asymmetries between achromatic increments and decrements: Perceptual scales and discrimination thresholds.

The perceptual response to achromatic incremental (A+) and decremental (A-) visual stimuli is known to be asymmetrical, due most likely to differences between ON and OFF channels. In the current study, we further investigated this asymmetry psychophysically. In Experiment 1, maximum likelihood difference scaling (MLDS) was used to estimate separately observers' perceptual scales for A+ and A-. In Experiment 2, observers performed two spatial alternative forced choice (2SAFC) pedestal discrimination on multiple pedestal contrast levels, using all combinations of A+ and A- pedestals and tests. Both experiments showed the well-known asymmetry. The perceptual scale curves of A+ follow a modified Naka-Rushton equation, whereas those of A- follow a cubic function. Correspondingly, the discrimination thresholds for the A+ pedestal increased monotonically with pedestal contrast, whereas the thresholds of the A- pedestal first increased as the pedestal contrast increased, then decreased as the contrast became higher. We propose a model that links the results of the two experiments, in which the pedestal discrimination threshold is inversely related to the derivative of the perceptual scale curve. Our findings generally agree with Whittle's previous findings (Whittle, 1986, 1992), which also included strong asymmetry between A+ and A-. We suggest that the perception of achromatic balanced incremental and decremental (bipolar) stimuli, such as gratings or flicker, might be dominated by one polarity due to this asymmetry under some conditions.

Air pollution levels enhance green bond investment: green preference and environmental perception thresholds

Environmental change is a crucial factor influencing green investment, and air pollution affects green assets through green preference. This study analyzes the impact of air pollution levels on the green bond using the threshold model. Since investors have physiological thresholds for perceiving air pollution, green preferences change investor behavior once air pollution reaches a certain threshold. The empirical results confirm that at low air pollution levels, weak physical stimuli are not sufficient to induce strong environmental perceptions, resulting in an insignificant role for green preference. However, when air pollution exceeds the threshold, the effect of air pollution becomes significantly positive due to enhanced environmental perceptions. Additionally, major crisis events (e.g. COVID-19) may weaken the role of green preference by distracting investors, leading to an insignificant impact of air pollution on green bonds after the crisis. These findings help enterprises to achieve green transformation and sustainable development through green debt financing.

Exploring Metschnikowia pulcherrima as a Co-Fermenter with Saccharomyces cerevisiae: Influence on Wine Aroma during Fermentation and Ageing

Non-Saccharomyces yeasts, particularly Metschnikowia pulcherrima, are considered alternatives to SO2 in winemaking, combating specific microorganisms. The sensory profile of the wine is contingent upon the type of yeast, the fermentation conditions, and the concentration and mode of application with Saccharomyces cerevisiae strains (whether pure or used in mixed/sequential co-fermentation). This study assessed the aroma in red wines produced with S. cerevisiae (Sc) and M. pulcherrima (Mp, non-Sc), incorporating variations in the method of addition and the inclusion or exclusion of SO2. The enological parameters of the wines were slightly affected. Volatile compounds were analysed in the wines through gas chromatography–mass spectrometry (GC-MS) at three moments: at the end of malolactic fermentation (MLF) and after 6 and 9 months of bottle ageing. Sequential fermentation of Sc and Mp reduced the concentration of most identified alcohols and acids, which is favourable, as these compounds can yield undesirable aromas at high concentrations. Regardless of the yeast mixture and Mp dose, a majority of the acetate esters and ethyl esters were quantified at concentrations above their perception thresholds, thus enhancing the sensory quality of the wines. Sensory analysis of wines showed generally positive evaluations. Using non-Saccharomyces as an alternative to SO2 improves the aromatic profile of wines.

High-speed fluidic processing circuits for dynamic control of haptic and robotic systems.

Fluidic logic circuits simplify system design for soft robotics by eliminating bulky components while enabling operation in a range of hostile environments that are incompatible with electronics but at the expense of limited computational capabilities and response times on the order of seconds. This paper presents a four-terminal fluidic transistor optimized for fast switching times, reduced component count, low unit cost, and high reproducibility to achieve complex fluidic control circuits while maintaining flow rates of liters per minute. A ring oscillator using three fluidic transistors achieves oscillation frequencies up to a kilohertz with full signal propagation, tolerating billions of cycles without failure. Fundamental processor circuits like a full adder and a 3-bit analog-to-digital converter require just seven transistors each. A decode circuit drives a high-resolution soft haptic display with refresh times below the human perception threshold for latency, and an electronics-free control circuit performs closed-loop position control of a pneumatic actuator with disturbance rejection, demonstrating the value across domains.

Effects of triceps surae exercise-induced delayed onset muscle soreness on control of body stability in different postures

This research aimed to determine whether triceps surae delayed onset muscle soreness (DOMS) affects stability while performing different postural control tasks requiring upright and landing stabilization. Twenty-four participants who self-reported as healthy were recruited. Pre and 48 h after a protocol to induce DOMS in the triceps surae, participants were evaluated for DOMS perception, pressure pain threshold, and postural control (assessed by the center of pressure, CoP) during different standing and landing stabilization tasks. We found higher DOMS perception and lower pressure pain threshold 48 h after the exercise. Mediolateral CoP displacement was more sensitive to DOMS across different postural tasks, but no effects were found for bilateral standing. The landing time to stabilization elicited high individual variability in the presence of DOMS. Effects of DOMS in the performance of less challenging tasks, such as bipedal standing, were not found. We conclude that DOMS in the triceps surae impairs mediolateral postural control during challenging tasks such as unilateral standing and body forward lean. It highlights the need for caution and individualized approaches when incorporating movements requiring frontal plane control in training and rehabilitation sessions under the presence of DOMS.