Mean Discharge Rate Research Articles

Resilient Coastal Protection Infrastructures: Probabilistic Sensitivity Analysis of Wave Overtopping Using Gaussian Process Surrogate Models

This paper presents a novel mathematical framework for assessing and predicting the resilience of critical coastal infrastructures against wave overtopping hazards and extreme climatic events. A probabilistic sensitivity analysis model is developed to evaluate the relative influence of hydrodynamic, geomorphological, and structural factors contributing to wave overtopping dynamics. Additionally, a stochastic Gaussian process (GP) model is introduced to predict the mean overtopping discharge from coastal defences. Both the sensitivity analysis and the predictive models are validated using a large homogeneous dataset comprising 163 laboratory and field-scale tests. Statistical evaluations demonstrate the superior performance of the GPs in identifying key parameters driving wave overtopping and predicting mean discharge rates, outperforming existing regression-based formulae. The proposed model offers a robust predictive tool for assessing the performance of critical coastal protection infrastructures under various climate scenarios.

Evolution Characteristics of Heilongtan Spring Discharge and Its Response Law to Precipitation in Lijiang City, China

The contradiction between water supply and spring preservation issues is becoming increasingly apparent as Lijiang City develops. An investigation into the dynamic variations in the discharge rate of Heilongtan Spring in Lijiang City and the response law between the water level of the spring and precipitation is crucial for safeguarding the landscape water of Heilongtan Spring. This study employed linear regression analysis, Mann–Kendall (MK) mutation test, wavelet analysis, and vector autoregression (VAR) to examine the fluctuating pattern of the Heilongtan Spring discharge and the response of the Heilongtan Spring water level to precipitation in Lijiang City. Furthermore, the study discussed the influence of human activities on the alteration of Heilongtan Spring. The results indicate that the mean discharge rate of Heilongtan Spring is 0.94 m3/s, with an annual variation of 0.05 m3/s. The time series analysis reveals that the variation pattern of Heilongtan Spring discharge aligns with the precipitation trend in Lijiang City. Nevertheless, there is a distinction between the timing of the Heilongtan Spring discharge station point and the precipitation mutation point in Lijiang City. The significant primary cycle of spring discharge change occurs every 18 months, with a cycle length of 12 months. The vector autoregression (VAR) model demonstrates a lagged relationship between the water level of Heilongtan Spring and the precipitation in Lijiang City. Specifically, the water level of Heilongtan Spring has a four-month lag response to precipitation variability in Lijiang City. The results can provide a beneficial reference for preserving spring water and managing regional water resources.

Achilles tendon morpho-mechanical parameters are related to triceps surae motor unit firing properties.

Recent studies combining high-density surface electromyography (HD-sEMG) and ultrasound imaging have yielded valuable insights into the relationship between motor unit activity and muscle contractile properties. However, limited evidence exists on the relationship between motor unit firing properties and tendon morpho-mechanical properties. This study aimed to determine the relationship between triceps surae motor unit firing properties and the morpho-mechanical properties of the Achilles tendon (AT). Motor unit firing properties [i.e. mean discharge rate (DR) and coefficient of variation of the interspike interval (COVisi)] and motor unit firing-torque relationships [cross-correlation between cumulative spike train (CST) and torque, and the delay between motor unit firing and torque production (neuromechanical delay)] of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SO) muscles were assessed using HD-sEMG during isometric plantarflexion contractions at 10% and 40% of maximal voluntary contraction (MVC). The morpho-mechanical properties of the AT (i.e. length, thickness, cross-sectional area, and resting stiffness) were determined using B-mode ultrasonography and shear-wave elastography. Multiple linear regression analysis showed that at 10% MVC, the DR of the triceps surae muscles explained 41.7% of the variance in resting AT stiffness. In addition, at 10% MVC, COVisi SO predicted 30.4% of the variance in AT length. At 40% MVC, COVisi MG and COVisi SO explained 48.7% of the variance in AT length. Motor unit-torque relationships were not associated with any morpho-mechanical parameter. This study provides novel evidence of a contraction intensity-dependent relationship between motor unit firing parameters of the triceps surae muscle and the morpho-mechanical properties of the AT. NEW & NOTEWORTHY By employing HD-sEMG, conventional B-mode ultrasonography, and shear-wave elastography, we showed that the resting stiffness of the Achilles tendon is related to mean discharge rate of triceps surae motor units during low-force isometric plantarflexion contractions, providing relevant information about the complex interaction between rate coding and the muscle-tendon unit.

Distinct Neural Drives along the Semitendinosus Muscle.

Conflicting results have been reported on the functional role of the proximal and distal compartments of the semitendinosus (ST) muscle. This study compared the discharge characteristics of motor units (MUs) in the two compartments at three knee-joint angles (0°: long length, 45°: intermediate length, and 90°: short length). Twenty men (21.4 ± 2.3 years) performed steady isometric contractions with the knee flexors at four target forces: 10%, 20%, 40%, and 60% of maximum voluntary contraction (MVC). High-density electromyography (EMG) signals were recorded to examine the MU discharge characteristics in the two compartments. Measurements included recruitment threshold (RT), mean discharge rate (MDR), coefficient of variation for interspike interval (CoV for ISI), and the standard deviation of filtered cumulative spike train (SD of fCST). Additionally, the within- and between-compartment association of the neural drive was calculated. Analysis of variance indicated that maximal force, absolute EMG amplitude during the MVCs, and force steadiness (CoV for force) were greater at the longest muscle length than the other two lengths (P < 0.05). Linear mixed models showed that both RT and CoV for ISI were similar between compartments (P > 0.05) at each of the three knee-joint angles. However, MDR and the variability in neural drive were greater for the proximal than the distal compartment (P < 0.05). The between-compartment association in neural drive (fCST) was relatively low. There were distinct differences in motor unit discharge characteristics between the proximal and distal compartments of ST across its operating range of muscle lengths and each compartment received a relatively distinct neural drive. These findings emphasize the importance of recognizing differences in neural control of the ST compartments to guide related interventions and inform rehabilitation strategies.

A mixed-method review of the efficacy of a virtual fracture clinic: an 8-year follow up

Background: Virtual fracture clinics are well established methods of managing trauma patients safely and effectively. While they have been widely adopted, there is a lack of research on their longer-term implementation and success. Aims: This paper aimed to review factors that may influence the success of a virtual fracture clinic. Methods: Business analytics were used to calculate clinic discharge and return rates, as well as the reasons for them. Qualitative analysis was used to look at patient satisfaction with virtual consultations; data were extracted from two differing time points via telephone interviews. Results: The mean discharge rate across the 2014–2021 period was 28%. The largest discharge rate was seen in 2014 (43%) and the lowest was seen in 2021 (28%). Return rates to the emergency department at the two different time points were 2% and 0.9% respectively. Patient satisfaction was rated as ‘good’ or higher in all parameters at both time points. Discussion: This article describes the long-term success of a virtual fracture clinic. Results demonstrate excellent patient satisfaction coupled with the lowest return rates in the published literature. Discharge rates started extremely high and have declined with time. The factors for these results are discussed along with ideas for further prospective research.

Neural Filtering of Physiological Tremor Oscillations to Spinal Motor Neurons Mediates Short-Term Acquisition of a Skill Learning Task.

The acquisition of a motor skill involves adaptations of spinal and supraspinal pathways to alpha motoneurons. In this study, we estimated the shared synaptic contributions of these pathways to understand the neural mechanisms underlying the short-term acquisition of a new force-matching task. High-density surface electromyography (HDsEMG) was acquired from the first dorsal interosseous (FDI; 7 males and 6 females) and tibialis anterior (TA; 7 males and 4 females) during 15 trials of an isometric force-matching task. For two selected trials (pre- and post-skill acquisition), we decomposed the HDsEMG into motor unit spike trains, tracked motor units between trials, and calculated the mean discharge rate and the coefficient of variation of interspike interval (COVISI). We also quantified the post/pre ratio of motor units' coherence within delta, alpha, and beta bands. Force-matching improvements were accompanied by increased mean discharge rate and decreased COVISI for both muscles. Moreover, the area under the curve within alpha band decreased by ∼22% (TA) and ∼13% (FDI), with no delta or beta bands changes. These reductions correlated significantly with increased coupling between force/neural drive and target oscillations. These results suggest that short-term force-matching skill acquisition is mediated by attenuation of physiological tremor oscillations in the shared synaptic inputs. Supported by simulations, a plausible mechanism for alpha band reductions may involve spinal interneuron phase-cancelling descending oscillations. Therefore, during skill learning, the central nervous system acts as a matched filter, adjusting synaptic weights of shared inputs to suppress neural components unrelated to the specific task.

Foot-dominance does not influence force variability during ankle dorsiflexion and foot adduction

ABSTRACT The aim of our study was to compare the force steadiness and the discharge characteristics of motor units in the tibialis anterior (TA) during ankle dorsiflexion and foot adduction produced by submaximal isometric contractions with the dominant and non-dominant foot. Fifteen young men performed maximal and submaximal contractions at five target forces with both legs, and motor unit activity in TA was recorded using high-density electromyography. Maximal force and the fluctuations in force during submaximal contractions were similar between the two legs (p > 0.05). Motor unit activity was characterized by measures of mean discharge rate (MDR), coefficient of variation for interspike interval (CoV for ISI), and standard deviation of the filtered cumulative spike train (SD of fCST). There were no statistically significant differences in motor unit activity between legs during ankle dorsiflexion. In contrast, the MDR and the CoV for ISI but not the SD of fCST, were greater for the non-dominant foot compared with the dominant foot during foot adduction. Nonetheless, these differences in motor unit activity were not sufficient to influence the force fluctuations during the submaximal contractions. These results indicate that control of the force produced by TA during the two actions was not influenced by limb dominance.

More Variability in Tibialis Anterior Function during the Adduction of the Foot than Dorsiflexion of the Ankle.

The aim of the study was to compare maximal force, force steadiness, and the discharge characteristics of motor units in the tibialis anterior (TA) muscle during submaximal isometric contractions for ankle dorsiflexion and adduction of the foot. Nineteen active young adults performed maximal and submaximal isometric dorsiflexion and adduction contractions at five target forces (5%, 10%, 20%, 40%, and 60% maximal voluntary contraction [MVC]). The activity of motor units in TA was recorded by high-density EMG. The maximal force was similar between dorsiflexion and adduction, despite EMG amplitude for TA being greater ( P < 0.05) during dorsiflexion than adduction. Τhe coefficient of variation (CV) for force (force steadiness) during dorsiflexion was always less ( P < 0.05) than during adduction, except of 5% MVC force. No differences were observed for mean discharge rate; however, the regression between the changes in discharge rate relative to the change of force was significant for dorsiflexion ( R2 = 0.25, P < 0.05) but not for adduction. Discharge variability, however, was usually less during dorsiflexion. The CV for interspike interval was less ( P < 0.05) at 10%, 20%, and 40% MVC but greater at 60% MVC during dorsiflexion than adduction. Similarly, the SD values of the filtered cumulative spike train of the motor units in TA were less ( P < 0.05) at 5%, 10%, 20%, and 40% MVC during dorsiflexion than adduction. Although the mean discharge rate of motor units in TA was similar during foot adduction and ankle dorsiflexion, discharge variability was less during dorsiflexion resulting in less accurate performance of the steady adduction contractions. The neural drive to bifunctional muscles differs during their accessory function, which must be considered for training and rehabilitation interventions.

Footedness but not dominance influences force steadiness during isometric dorsiflexion in young men

The aim of the study was to assess the potential influence of footedness and dominance on maximal force, force fluctuations and neural drive during dorsiflexion. Fifteen left-footed (LF) and fifteen right-footed (RF) young adults performed 2 maximal voluntary contractions (MVC) and 3 steady submaximal isometric contractions at five target forces (5, 10, 20, 40 and 60% MVC) with the dorsiflexors of both legs. High-density electromyography (EMG) was used to record the discharge characteristics of motor units (MUs) of Tibialis Anterior. MVC force and EMG amplitude (root mean square) were similar between the two legs and groups (p > 0.05). Force fluctuations (Coefficient of Variation, CoV for force), mean discharge rate of MUs, discharge variability (CoV of interspike interval), and variability in neural drive (standard deviation of filtered cumulative spike train) were greater (p < 0.05) and the input–output gain of the MUs (ΔDR/ΔF) was lower (p < 0.05) for the LF relative to the RF group. The differences in force fluctuations during steady contractions with the dorsiflexors were associated with footedness but not with dominance. They reflect greater variability in motor neuron output, as suggested by coefficient of variation for interspike interval (independent input) and the standard deviation of the smoothed discharge times (common input).

Forest-cover-loss control on year-round river flow dynamics in the upper Saint John River (Wolastoq) basin, Northeastern North America from 2001 to 2019

Forest-cover removal has led to substantial changes in stream and river flow dynamics globally. The objective of this study was to characterize the daily-to-seasonal forcing of discharge rates in a large, international river in northeastern North America. During a 19-year period (i.e., 2001–2019), forest-cover in the upper Saint John River (Wolastoq) basin was routinely removed as part of large-scale, commercial forestry operations. Annual mean forest-cover removal ranged from 0.39 to 1.35% of basin area, with an obvious increasing trend of 7.7% per year. The long-term annual mean discharge rate at the basin outlet was 457.5 m3 s−1. An analysis based on extreme gradient boosting revealed that daily discharge rates during the snowmelt season were largely influenced by (i) cumulative snow degree-days, as proxy of springtime northeasterly advection of warm-moist air from southerly positions and affiliated increases in snowmelt, (ii) cumulative, on-the-ground snow water equivalent (SWE), and (iii) extent of within-basin, annual forest-cover removal. In contrast, daily discharge rates during the warm period of the year (i.e., June–October) was controlled primarily by warm-season degree-days and annual forest-cover removal. Spring flood maxima increased by 2.1% per year with annual forest-cover loss, whereas mid-summer discharge rates tended to drop. We used wavelet analysis to investigate the role of related environmental variables in controlling river flow dynamics across the time–frequency domain. Annually, the time lag between peak discharge rate and SWE significantly decreased with increasing annual forest-cover removal, suggesting an accelerated melting season. This study has important implications for river flow dynamics in a large river system prone to spring flooding and low waterflow events in summer.

Alternating or Bilateral Exercise Training does not Influence Force Control during Single-Leg Submaximal Contractions with the Dorsiflexors.

The aim of the study was to assess the influence of habitual training history on force steadiness and the discharge characteristics of motor units in tibialis anterior during submaximal isometric contractions. Fifteen athletes whose training emphasized alternating actions (11 runners and 4 cyclists) and fifteen athletes who relied on bilateral actions with leg muscles (7 volleyball players, 8 weight-lifters) performed 2 maximal voluntary contractions (MVC) with the dorsiflexors, and 3 steady contractions at 8 target forces (2.5%, 5%, 10%, 20%, 30%, 40%, 50% and 60% MVC). The discharge characteristics of motor units in tibialis anterior were recorded using high-density electromyography grids. The MVC force and the absolute (standard deviation) and normalized (coefficient of variation) amplitudes of the force fluctuations at all target forces were similar between groups. The coefficient of variation for force decreased progressively from 2.5% to 20% MVC force, then it plateaued until 60% MVC force. Mean discharge rate of the motor units in tibialis anterior was similar at all target forces between groups. The variability in discharge times (coefficient of variation for interspike interval) and the variability in neural drive (coefficient of variation of filtered cumulative spike train) was also similar for the two groups. These results indicate that athletes who have trained with either alternating or bilateral actions with leg muscles has similar effects on maximal force, force control, and variability in the independent and common synaptic input during a single-limb isometric task with the dorsiflexors.

Flexor hallucis brevis motor unit behavior in response to moderate increases in rate of force development.

Studies on motor unit behaviour with varying rates of force development have focussed predominantly on comparisons between slow and ballistic (i.e., very fast) contractions. It remains unclear how motor units respond to less extreme changes in rates of force development. Here, we studied a small intrinsic foot muscle, flexor hallucis brevis (FHB) where the aim was to compare motor unit discharge rates and recruitment thresholds at two rates of force development. We specifically chose to investigate relatively slow to moderate rates of force development, not ballistic, as the chosen rates are more akin to those that presumably occur during daily activity. We decomposed electromyographic signals to identify motor unit action potentials obtained from indwelling fine-wire electrodes in FHB, from ten male participants. Participants performed isometric ramp-and-hold contractions from relaxed to 50% of a maximal voluntary contraction. This was done for two rates of force development; one with the ramp performed over 5 s (slow condition) and one over 2.5 s (fast condition). Recruitment thresholds and discharge rates were calculated over the ascending limb of the ramp and compared between the two ramp conditions for matched motor units. A repeated measures nested linear mixed model was used to compare these parameters statistically. A linear repeated measures correlation was used to assess any relationship between changes in recruitment threshold and mean discharge rate between the two conditions. A significant increase in the initial discharge rate (i.e., at recruitment) in the fast (mean: 8.6 ± 2.4 Hz) compared to the slow (mean: 7.8 ±2.3 Hz) condition (P = 0.027), with no changes in recruitment threshold (P = 0.588), mean discharge rate (P = 0.549) or final discharge rate (P = 0.763) was observed. However, we found substantial variability in motor unit responses within and between conditions. A small but significant negative correlation (R2 = 0.33, P = 0.003) was found between the difference in recruitment threshold and the difference in mean discharge rate between the two conditions. These findings suggest that as force increases for contractions with slower force development, increasing the initial discharge rate of recruited motor units produces the increase in rate of force development, without a change in their recruitment thresholds, mean or final discharge rate. However, an important finding was that for only moderate changes in rate of force development, as studied here, not all units respond similarly. This is different from what has been described in the literature for ballistic contractions in other muscle groups, where all motor units respond similarly to the increase in neural drive. Changing the discharge behaviour of a small group of motor units may be sufficient in developing force at the required rate rather than having the discharge behaviour of the entire motor unit pool change equally.

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study.

Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT). We recruited runners with (n = 12) and without (n = 13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using high-density surface electromyography during 10 and 20% isometric plantar flexor contractions. MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24 pps (95% CI 7.08 to 9.41) to 20%, 8.52 pps (7.41 to 9.63, p = 0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39 pps (7.25-9.53) to 20%, 10.07pps (8.89-11.25, p < 0.001). There were no between-group difference in gastrocnemius medialis (GM) or soleus (SOL) MU discharge rates. We found no between-group differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness. Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focussing on increasing neural drive to GL would affect muscle function in runners with AT.

A Proposed Approach towards Quantifying the Resilience of Water Systems to the Potential Climate Change in the Lali Region, Southwest Iran

Computing the resilience of water resources, especially groundwater, has hitherto presented difficulties. This study highlights the calculation of the resilience of water resources in the small-scale Lali region, southwest Iran, to potential climate change in the base (1961–1990) and future (2021–2050) time periods under two Representative Concentration Pathways, i.e., RCP4.5 and RCP8.5. The Lali region is eminently suitable for comparing the resilience of alluvial groundwater (Pali aquifer), karst groundwater (Bibitarkhoun spring and the observation wells W1, W2 and W3) and surface water (Taraz-Harkesh stream). The log-normal distribution of the mean annual groundwater level and discharge rate of the water resources was initially calculated. Subsequently, different conditions from extremely dry to extremely wet were assigned to the different years for every water system. Finally, the resilience values of the water systems were quantified as a number between zero and one, such that they can be explicitly compared. The Pali alluvial aquifer demonstrated the maximum resilience, i.e., 1, to the future climate change. The Taraz-Harkesh stream, which is fed by the alluvial aquifer and the Bibitarkhoun karst spring, which is the largest spring of the Lali region, depicted average resilience of 0.79 and 0.59, respectively. Regarding the karstic observation wells, W1 being located in the recharge zone had the lowest resilience (i.e., 0.52), W3 being located in the discharge zone had the most resilience (i.e., 1) and W2 being located between W1 and W3 had an intermediate resilience (i.e., 0.60) to future climate change.

La réalité virtuelle, un outil pertinent pour la sensibilisation au métier de masseur-kinésithérapeute

The motor cortex plays a critical role in accurate visually guided movements such as reaching and target stepping. However, the manner in which vision influences the movement-related activity of neurons in the motor cortex is not well understood. In this study we have investigated how the locomotion-related activity of neurons in the motor cortex is modified when subjects switch between walking in the darkness and in light.Three adult cats were trained to walk through corridors of an experimental chamber for a food reward. On randomly selected trials, lights were extinguished for approximately 4 s when the cat was in a straight portion of the chamber's corridor. Discharges of 146 neurons from layer V of the motor cortex, including 51 pyramidal tract cells (PTNs), were recorded and compared between light and dark conditions. It was found that while cats’ movements during locomotion in light and darkness were similar (as judged from the analysis of three-dimensional limb kinematics and the activity of limb muscles), the firing behavior of 49% (71/146) of neurons was different between the two walking conditions. This included differences in the mean discharge rate (19%, 28/146 of neurons), depth of stride-related frequency modulation (24%, 32/131), duration of the period of elevated firing ([PEF], 19%, 25/131), and number of PEFs among stride-related neurons (26%, 34/131). 20% of responding neurons exhibited more than one type of change.We conclude that visual input plays a very significant role in determining neuronal activity in the motor cortex during locomotion by altering one, or occasionally multiple, parameters of locomotion-related discharges of its neurons.

Cold thermal energy storage for industrial CO2 refrigeration systems using phase change material: An experimental study

Refrigeration systems in industrial food processing plants are large users of electric energy and often show high peak power consumption. Cold thermal energy storage (CTES) technology integrated into refrigeration systems can reduce the peak power requirement and achieve peak shifting by decoupling the supply and demand of the refrigeration load. This paper presents the design and performance of a CTES unit consisting of a pillow plate heat exchanger (PP-HEX) immersed into a low-temperature phase change material (PCM) as the storage medium. It is one of the first experimental investigations featuring a large-scale technical solution that allows for coupling the evaporation and condensation processes of the refrigeration system with the melting and solidification of a low-temperature PCM in the same heat exchanger. The charging and discharging performance of the plates-in-tank CTES unit was extensively tested using CO2 as the refrigerant and a commercial PCM with phase change temperature of -9.6 °C. The charging time was found to be mainly affected by the refrigerant evaporation temperature, while the discharging rate and discharged energy over the cycle was higher when increasing the refrigerant condensing temperature. Using a plate pitch of 30 mm resulted in the highest mean discharge rate and total discharged energy over the cycle with 9.79 kW and 17.04 kWh, respectively. The flexible CTES-PCM unit can be adapted to fit several refrigeration load characteristics and temperature levels by changing the PP-HEX geometry and type of PCM used as the storage medium.

Role of Microelectrode Recording in Deep Brain Stimulation of the Pedunculopontine Nucleus: A Physiological Study of Two Cases

BackgroundDeep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) has been reported to improve gait disturbances in Parkinson's disease (PD); however, there are controversies on the radiological and electrophysiological techniques for intraoperative and postoperative confirmation of the target and determination of optimal stimulation parameters. ObjectivesWe investigated the correlation between the location of the estimated PPN (ePPN) and neuronal activity collected during intraoperative electrophysiological mapping to evaluate the role of microelectrode recording (MER) in identifying the effective stimulation site in two PD patients. Materials and MethodsBilateral PPN DBS was performed in two patients who had suffered from levodopa refractory gait disturbance. They had been implanted previously with DBS in the internal globus pallidus and the subthalamic nucleus, respectively. The PPN was determined on MRI and identified by intraoperative MER. Neuronal activity recorded was analyzed for mean discharge rate, bursting, and oscillatory activity. The effects were assessed by clinical ratings for motor signs before and after surgery. ResultsThe PPN location was detected by MER. Groups of neurons characterized by tonic discharges were found 9–10 mm below the thalamus. The mean discharge rate in the ePPN was 19.1 ± 15.1 Hz, and 33% of the neurons of the ePPN responded with increased discharge rate during passive manipulation of the limbs and orofacial structures. PPN DBS with bipolar stimulation at a frequency range 10–30 Hz improved gait disturbances in both patients. Although PPN DBS provided therapeutic effects post-surgery in both cases, the effects waned after a year in case 1 and three years in case 2. ConclusionsEstimation of stimulation site within the PPN is possible by combining physiological guidance using MER and MRI findings. The PPN is a potential target for gait disturbances, although the efficacy of PPN DBS may depend on the location of the electrode and the stimulation parameters.

Leg Dominance Does Not Influence Maximal Force, Force Steadiness, or Motor Unit Discharge Characteristics.

The aim of our study was to compare maximal force, force steadiness, and discharge characteristics of motor units in tibialis anterior during contractions with the dorsiflexors of the dominant and nondominant legs at low-to-moderate target forces and three ankle angles. Twenty young adults performed maximal and submaximal isometric contractions (5%, 10%, 20%, 40%, and 60% of maximal voluntary contraction (MVC)) with the dorsiflexors of the dominant and nondominant legs at three ankle angles (75°, short length; 90°, intermediate length; 105°, long length). High-density EMG signals from the tibialis anterior muscle of each leg were recorded. Maximal force (average dominant, 182.9 ± 64.5 N; nondominant, 179.0 ± 58.8 N) and the fluctuations in force, quantified as absolute (SD) and normalized amplitudes (coefficient of variation (CoV)), were similar between the two legs across the three ankle angles (average CoV for dominant, 1.5% ± 1.0%; nondominant, 1.7% ± 1.3%). The CoV for force for both legs decreased from 5% to 20% MVC force, and then it plateaued at 40% and 60% MVC force. EMG amplitude, mean discharge rate of motor units, discharge variability (interspike interval), and the variability in neural drive (filtered cumulative spike train) were similar between the two legs across the submaximal contractions. MVC force and force steadiness were similar across ankle angles and target forces between the dominant and nondominant legs. The attributes that underlie the self-reported identification of a dominant leg were not associated with the force capacity or the control of force for the dorsiflexor muscles, at least during isometric contractions.

Experimental characterisation of a cold thermal energy storage unit with a pillow-plate heat exchanger design

• Design of a novel cold thermal energy storage unit for CO 2 refrigeration systems. • Investigation of the charging and discharging performance of the unit. • Variation of the heat exchanger geometry to adapt to different refrigeration load. • Condensation and evaporation temperature of CO 2 are the most critical parameters. • Maximum discharged energy is 35.29 kWh over 4.5 h with a mean rate of 7.90 kW. Cold Thermal Energy Storage (CTES) technology can be introduced to refrigeration systems for air conditioning and process cooling to reduce the peak power consumption by decoupling the supply and demand of refrigeration. In these systems, the refrigeration demand can vary significantly over a day, resulting in a challenging peak and valley load pattern on the electrical grid. This paper presents the design, development, and experimental performance investigations of a novel plates-in-tank CTES unit design intended for integration into pump-circulated CO 2 industrial refrigeration systems. The CTES unit is composed of a stainless steel container filled with water as the latent storage medium and fitted with a pillow plate heat exchanger. The refrigerant (CO 2 ) circulates within the heat exchanger to transfer heat with the storage medium. The current study demonstrates the feasibility of implementing a latent CTES unit directly into the primary refrigerant circuit for peak shaving of the refrigeration load. The results show that the evaporation and condensation temperatures of the refrigerant are the most critical parameters influencing the performance of the charging and discharging cycles, respectively. The unit demonstrated a mean discharge rate of 7.90 kW over a total discharging cycle time of approximately 4.5 h. The resulting maximum discharged energy was calculated to 35.29 kWh.

Variability of neuronal responses in the posterior superior temporal sulcus predicts choice behavior during social interactions.

Recent studies have shown that neural activity in a well-defined patch in the posterior superior temporal sulcus (the "gaze-following patch," GFP) of the primate brain is strongly modulated when the other's gaze attracts the observer's attention to locations/objects, the other is looking at. Changes of the mean discharge rate of neurons in the monkey GFP indicate that they are involved in two distinct computations: the allocation of spatial attention guided by the other's gaze vector and the suppression of gaze following if inappropriate in a given situation. Here, we asked if and how the discharge variability of neurons in the GFP is related to the task and if it carries information on behavioral performance. To this end, we calculated the Fano factor as a measure of across-trial discharge variability as a function of time. Our results show that all neurons exhibiting a task-related discharge-rate modulation also exhibit a stimulus onset-dependent drop in the Fano factor. Furthermore, the amplitude of the Fano factor reduction is modulated by task condition and the neuron's selectivity in this regard. We found that these effects are directly related to the monkeys' behavioral performance in that the Fano factor is predictive about upcoming correct or wrong decisions. Our results indicate that neuronal discharge variability as gauged by the Fano factor, hitherto primarily studied in the context of visual perception or motor control, is an informative measure also in studies of the neural underpinnings of complex social behavior.NEW & NOTEWORTHY Quenching of neural variability following stimulus onset is a widely accepted phenomenon. However, the relevance of quenching for the shaping of complex social behaviors remains to be explored. Here, we show that task selective neurons in the GFP exhibit a higher degree of variability quenching than their neighboring unselective neurons. Furthermore, we demonstrate that behavioral errors are not only associated with lower firing rates but also less variability quenching, suggesting that both facilitate optimal performance.