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Background Stroke survivors suffer from hemiparesis and somatosensory impairments, which adversely impact walking performance, placing them at higher risks for trips and falls. Post-stroke, somatosensory deficits are commonly observed as impaired interpretation of afferent input and increased threshold. Diminishing or augmenting somatosensory inputs via various techniques have been demonstrated to be able to modify static and dynamic balance, postural and locomotor control in non-neurologically impaired as well as neurologically impaired individuals. Research question: We sought to investigate whether enhancing somatosensory input using vibratory insoles, can improve post-stroke gait. We hypothesized that with augmentation of somatosensory input at the soles via vibratory insoles would improve post-stroke gait via increased propulsive forces, decreased braking forces and increased ankle angle movements in the paretic legs of individuals with chronic post-stroke hemiparesis. Methods Fifteen individuals with chronic post-stroke hemiparesis and 15 age-similar non-neurologically impaired controls participated in this cross-sectional study. Enhanced somatosensory stimulation was delivered using a pair of tactor-embedded insoles, providing suprathreshold vibratory stimulation to the bottom of the feet. Participants walked over an instrumented treadmill with self-selected speeds, under 5 conditions: no insole in shoe (NT), insoles in shoe with no vibration (BOFF), vibration under both feet (BON), vibration under one foot only (ION, CON). Kinetics and kinematics during walking were recorded and analyzed offline. Results Suprathreshold vibratory stimulations did not alter gait kinetics under any stimulation conditions. We observed increased paretic ankle dorsiflexions in the paretic legs, when vibratory stimuli were applied unilaterally. Significance Vibratory stimulations applied at suprathreshold intensity to the bottom of the feet to augment somatosensory feedback can potentially be used as a low-cost solution to address the inadequate toe clearance during walking in people post-stroke, which is an important goal in post-stroke rehabilitation.

ObjectiveTo evaluate the evidence for altered cortical and spinal cord functions in individuals with patellofemoral pain (PFP).MethodsWe conducted a comprehensive search of databases to appraise and analyze the studies published prior to December 10, 2021 that examined spinal reflex excitability measured using Hoffmann reflex (H-reflex) amplitudes, corticospinal excitability measured using transcranial magnetic stimulation (TMS)-elicited motor evoked potential (MEP) amplitudes, motor threshold (MT), or stimulus-response (SR) curves, cortical reorganization assessed using TMS cortical mapping or structural magnetic resonance imaging (MRI), or functional changes of the brain assessed using functional MRI (fMRI) in individuals with PFP.ResultsEight studies were eligible for analyses. While an earlier study showed that pain had no effect on the H-reflex amplitude of the quadriceps muscle, more recent evidence reported a decrease in vastus medialis (VM) H-reflex amplitude in participants with PFP. VM H-reflex amplitude was correlated with pain, chronicity, physical function, and isometric knee extensor torque production in participants with PFP. Altered corticospinal excitability was reported in participants with PFP, observed as increased MT in the VM and vastus lateralis (VL) muscles. In addition, cortical reorganization has been observed, where decreased number of cortical peaks, shifts and reduced volumes, and increased overlap of motor cortex representations for the VM, VL, and rectus femoris (RF) muscles were reported in participants with PFP.ConclusionThere is emerging evidence on altered cortical and spinal cord functions in individuals with PFP, however, solid conclusions cannot be drawn due to limited literature available. Further research is needed to better understand the adaptations of the brain and spinal cord in this population.Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero/, identifier: CRD42020212128.

IntroductionReduced neuromuscular control due to altered neurophysiological functions of the central nervous system has been suggested to cause movement deficits in individuals with patellofemoral pain (PFP). However, the underlying neurophysiological measures of brain and spinal cord in this population remain to be poorly understood. The purpose of this systematic review is to evaluate the evidence for altered cortical and spinal cord functions in individuals with PFP.Methods and analysisThe protocol for conducting the review was prepared using the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. We will systematically search the literature that examines cortical and spinal cord functions in individuals with PFP, aged 18–45 years. The studies for cross-sectional, prospective, longitudinal, case–control and randomised control trial designs will be included from the following databases: PubMed (MEDLINE), EMBASE and Web of Science. Only studies published in English prior to 1 February 2021 will be included. The risk of bias and quality assessment will be performed using National Institutes of Health’s Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. We will conduct meta-analysis of the data where appropriate. Narrative synthesis will be taken if a meta-analysis is not possible.Ethics and disseminationThis is a systematic review from the existing literature and does not require ethical approval. The results of this study will be published in a peer-reviewed journal in the field of rehabilitation medicine, sports/orthopaedic medicine or neurology, regardless of the outcome.PROSPERO registration numberCRD42020212128.

The purpose of this study was to employ inertial measurement units (IMU) with an eye-tracking device to investigate different swing strategies between two levels of batters. The participants were 20 healthy males aged 20 to 30 years old, with ten professional and ten amateur batters. Eye gaze position, head, shoulder, trunk, and pelvis angular velocity, and ground reaction forces were recorded. The results showed that professional batters rotated segments more rhythmically and efficiently than the amateur group. Firstly, the professional group spent less time in the preparation stages. Secondly, the maximum angular velocity timing of each segment of the professional group was centralized in the swing cycle. Thirdly, the amateur group had significantly earlier gaze timing of the maximum angular velocity than the professional group. Moreover, the maximum angular velocity timing of the gaze was the earliest parameter among the five segments, and significantly earlier (at least 16.32% of cycle time) than the maximum angular velocity of the head, shoulder, trunk, and pelvis within the amateur group. The visual-motor coordination strategies were different between the two groups, which could successfully be determined by wearable instruments of IMU.

Post-stroke rehabilitation often aims to increase walking speeds, as faster walking is associated with improved functional status and quality of life. However, for successful community ambulation, ability to modulate (increase and decrease) walking speeds is more important than walking continuously at constant speeds. Increasing paretic propulsive forces to increase walking speed has been extensively examined, however, little is known about the mechanics of slow walking post-stroke. The primary purpose of this study was to identify the effects of increased and decreased walking speeds on post-stroke kinetics and ankle kinematics. Fifteen individuals with chronic post-stroke hemiparesis and 15 non-neurologically impaired controls walked over an instrumented treadmill under: slow, self-selected, and fast walking speeds. We examined the peak propulsive forces, propulsive impulse, peak braking forces, braking impulse, and ankle kinematics under each condition. When walking at slow walking speeds, paretic limbs were unable to reduce braking impulse and peak propulsive force or modulate ankle kinematics. Impaired modulation of paretic gait kinetics during slow walking places people post-stroke at high risks for slip-related falls. These findings suggest the need for developing gait retraining paradigms for slow walking in individuals chronically post-stroke that target the ability of the paretic limb to modulate braking forces.

Postural stability is commonly decreased in individuals with chronic post-stroke hemiparesis due to multisystemic deficits. Transcranial direct current stimulation (tDCS) is a non-invasive method to modulate cortical excitability, inducing neuroplastic changes to the targeted cortical areas and has been suggested to potentially improve motor functions in individuals with neurological impairments. The purpose of this double-blinded, sham-controlled study was to examine the acute effects of anodal tDCS over the lesioned motor cortex leg area with concurrent limits of stability training on postural control in individuals with chronic post-stroke hemiparesis. Ten individuals with chronic post-stroke hemiparesis received either anodal or sham tDCS stimulation over the lesioned leg region of the motor cortex while undergoing 20 min of postural training. The type of stimulation to receive during the first session was pseudorandomized, and the two sessions were separated by 14 days. Before and immediately after 20 min of tDCS, the 10 m walk test, the Berg Balance Scale, and dynamic posturography assessments were performed. After a single session of anodal tDCS with concurrent postural training, we observed no changes in clinical measures of balance and walking, assessed using the Berg Balance Scale and 10 m walk test. For dynamic posturography assessments, participants demonstrated improvements in adaptation responses to toes-up and toes-down perturbations, regardless of the type of tDCS received. Additionally, improved performance in the shifting center of gravity was observed during anodal tDCS. Taken together, these preliminary findings suggest that tDCS can potentially be used as a feasible approach be incorporated into the rehabilitation of chronic post-stroke individuals with issues related to postural control and fear of falling, and that multiple sessions of tDCS stimulation may be needed to improve functional measures of postural control and walking.

Background Individuals post-stroke walk slowly and with more effort, which puts them at higher risks for falls. The slow walking speed results from insufficient propulsive forces generated by the paretic leg. Current rehabilitative efforts to improve walking function target increasing propulsive forces, but overlook the muscle-tendon unit. Case presentations Two individuals with chronic post-stroke hemiparesis are presented. In both individuals post-stroke, paretic ankle plantarflexors presented with increased muscle tone. Gait kinetics revealed asymmetric propulsive forces, specifically, insufficient propulsive forces by the paretic legs, consistent with previous literature. Sonography revealed increased thickness of paretic Achilles tendon at the calcaneal insertion, in both stroke cases, in contrast to comparable Achilles tendon thickness between limbs in the non-neurologically impaired controls. Conclusion Tendon unit integrity should be considered in individuals post-stroke who demonstrate abnormal muscle tone and insufficient propulsion during gait.

Standing on wedges changes the position in the ankle joints and affects postural stability in the medial-lateral direction. The objective of the study was to investigate the role of wedges and external lateral perturbations on anticipatory (APA) and compensatory postural adjustments (CPA). Ten healthy young participants were exposed to perturbations applied to the lateral part of their right shoulder when standing on a planar surface, on a medial or lateral wedges. Bilateral electromyographic activity of dorsal and ventral postural muscles and the center of pressure (COP) displacement were recorded and analyzed during the APA and CPA phases. When exposed to the lateral perturbation, reciprocal activation of shank muscles was seen on the side of the perturbation while co-contraction of shank muscles was seen on the contralateral side during the APA and CPA phases. Standing on a wedge was associated with decreased magnitudes of co-contraction and reciprocal activation of shank muscles. The COP displacements were smaller in the APA phase and larger in the CPA phase while standing on wedges compared to standing on the planar surface. The outcome of the study provides a basis for future investigations of incorporating wedges in balance re-training paradigms for the elderly or individuals with neurological impairment.

This paper analyses the synchronous measuring data of harmonic current in AC arc furnaces with method of functional analysis, calculates the interaction angle between serial data of harmonic current in two arc furnaces, gets the conclusion that serial data of harmonic current in two arc furnaces are orthogonal, derives superposition formula for synthesizing harmonic currents of multi-arc furnaces and formula for evaluating harmonic voltage level beforehand in construction of power supply area of AC arc furnaces.

Teaching point: The classic sonographic presentation of calcium pyrophosphate dihydrate crystal deposits in the Achilles tendon is reported.

Controllability of posture in the medial-lateral direction is critical for balance maintenance, particularly in step initiation. The objective of the current study was to examine the effects of external perturbation and landing orientation on medial-lateral control stability in step initiation. Eleven young healthy participants stood on the force platform and waited for the instruction of taking a step while experiencing a pendulum perturbation applied at the lateral side of the right shoulder. Eight experimental conditions were conducted by two levels of step side (right or left), two levels of perturbation (with or without), and two levels of landing orientation (forward or diagonal). The center of pressure (COP), pelvic movements, and muscle activities were recorded and analyzed as the onset of COP and pelvic movement, the COP displacement, and cocontraction and reciprocal muscle activation pattern. The temporal events of COP and pelvic movement were not significantly different in all experimental conditions. However, COP and pelvic movement were significantly later in the diagonal condition. Most of the segments showed reciprocal muscle activation patterns in relation to the perturbation released time. Subsequently, all segments showed cocontraction muscle activation patterns, which was significantly affected by step side, perturbation, and orientation. The results suggest that how the CNS initiated a step was identical with the COP then pelvic movement. The outcome highlights the importance of external perturbation and foot landing orientation effects on postural adjustments, which may provide a different approach to help step initiation.

Background and Purpose: Short term adaptations in the Ia afferent-motoneuron pathway, as measured using the H-reflex, in response to altered ground reaction forces (GRFs) applied at the feet during slope walking have been observed in the non-impaired nervous system. The ability of the stroke-impaired nervous system to adapt to altered GRFs have not been examined. The purpose of this study was to examine the acute effects of altered propulsion and braking forces applied at the feet, which naturally occurs when walking on different slopes, on adaptations of the H-reflex pathway in individuals with chronic post-stroke hemiparesis. Methods: Twelve individuals chronically post-stroke and 10 age-similar non-neurologically impaired controls walked on an instrumented treadmill for 20 minutes under level, upslope and downslope conditions. GRFs were measured during walking and soleus H-reflexes were recorded prior to and immediately after walking. A 3 (limbs: paretic, non-paretic, and non-impaired) X 3 (slope: level, upslope, downslope) mixed factorial ANOVA was conducted on the propulsive and braking forces. A 2 (limb: paretic and non-impaired) X 2 (time: pre and post) X 3 (slope: level, upslope, and downslope) mixed factorial ANOVA was conducted to assess the soleus H-reflex amplitudes. Results: In both post-stroke and non-impaired groups, during downslope walking, peak propulsive forces decreased, while peak braking forces increased. In contrast, during upslope walking, peak propulsive forces increased and peak braking forces decreased. We observed reduced soleus H-reflex amplitudes immediately following 20 minutes of level, downslope and upslope walking in non-impaired individuals but not in the paretic legs of individuals with chronic post-stroke hemiparesis. Discussion and Conclusions: Similar pattern of change in peak propulsive and braking forces with respect to different slopes was observed in both individuals post-stroke and non-impaired individuals, but the magnitude of GRFs were smaller in individuals post-stroke due to the slower walking speed. Our results suggested that impaired modulation of the H-reflex pathway potentially underlies the lack of neuroadaptations in individuals with chronic post-stroke hemiparesis.

Background Center of pressure (COP) trajectory during treadmill walking have been commonly presented using the butterfly diagram to describe gait characteristics in neurologically intact and impaired individuals. However, due to the large amount of displayed information, the butterfly diagram is not an efficient solution to visualize locomotor variability. Purpose The purpose of this study was to evaluate post-stroke locomotor variability by applying Kernel density estimation (KDE) on the intersections of the butterfly diagram, and to compare KDE derived metrics with conventional metrics of gait symmetry and variability. Methods Bilateral toe-off (TO) and initial contact (IC) points of the butterfly diagram were determined to calculate the COP symmetry index and the intersections of bilateral TO IC. Subsequently, the intersections during the walking window were used to evaluate its density and variability by Kernel density estimation. Standard deviations of step width and step length were compared between groups. Results Using the KDE surface plots we observed 4 characteristically different patterns with individuals post-stroke, which were associated with functional status quantified using walking speed and lower extremity Fugl-Meyer scores. However, locomotor variability quantified using standard deviations of step width and lengths did not differ between groups. Significance & Novelty: This paper presents a novel approach of using KDE analysis as a better and more sensitive method to characterize locomotor COP variability in individuals with post-stroke hemiparesis, compared to conventional metrics of gait symmetry and variability.

Correlations between the variations of quasar absorption lines and the ionizing continuum have been confirmed recently in systematic studies. However, no convincing individual case is reported. We present a statistical analysis of the variable C iv broad absorption line (BAL) in the quasar SDSS J141007.74+541203.3, which has been observed with 44 epochs by the Sloan Digital Sky Survey Data Release 14. Grier et al. have concluded that the most likely cause of the variability of the BAL in SDSS J141007.74+541203.3 is a rapid response to changes in the incident ionizing continuum. In this paper, we confirm the anticorrelation between the equivalent width of BALs and the flux of the continuum based on the spectra of this quasar, which show significant variations. This serves as further independent evidence for the conclusions of Grier et al.

Distal leg muscles receive neural input from motor cortical areas via the corticospinal tract, which is one of the main motor descending pathway in humans and can be assessed using transcranial magnetic stimulation (TMS). Given the role of distal leg muscles in upright postural and dynamic tasks, such as walking, a growing research interest in the assessment and modulation of the corticospinal tracts relative to the function of these muscles has emerged in the last decade. However, methodological parameters used in previous work have varied across studies making the interpretation of results from cross-sectional and longitudinal studies less robust. Therefore, use of a standardized TMS protocol specific to the assessment of leg muscles’ corticomotor response (CMR) will allow for direct comparison of results across studies and cohorts. The objective of this paper is to present a protocol that provides the flexibility to simultaneously assess the bilateral CMR of two main ankle antagonistic muscles, the tibialis anterior and soleus, using single pulse TMS with a neuronavigation system. The present protocol is applicable while the examined muscle is either fully relaxed or isometrically contracted at a defined percentage of maximum isometric voluntary contraction. Using each subject’s structural MRI with the neuronavigation system ensures accurate and precise positioning of the coil over the leg cortical representations during assessment. Given the inconsistency in CMR derived measures, this protocol also describes a standardized calculation of these measures using automated algorithms. Though this protocol is not conducted during upright postural or dynamic tasks, it can be used to assess bilaterally any pair of leg muscles, either antagonistic or synergistic, in both neurologically intact and impaired subjects.

Background: Task-dependent neurophysiological adaptations in people with cerebral palsy have been examined using various techniques such as functional magnetic resonance imaging, peripheral nerve stimulation in order to assess H-reflexes, and transcranial magnetic stimulation. This activity-dependent plasticity is hypothesized to improve specific gross motor function in individuals with cerebral palsy. Although these adaptations have been examined extensively, most studies examined tasks utilizing the upper limbs. The aim of this review is to assess the neurophysiological adaptations of the central nervous system in individuals with cerebral palsy during lower limb functional tasks. Methods: A systematic review and meta-analysis will be conducted to evaluate the neurophysiological changes in the brain and spinal cord associated with lower extremity tasks in individuals with cerebral palsy. We will search within PubMed, MEDLINE, Embase, PsychINFO, and CINAHL using a predetermined search string to identify and evaluate relevant studies. Two independent reviewers will screen these studies against our inclusion criteria and risks of bias, and will extract the data from each study. A third reviewer will be used to resolve any disagreement regarding the inclusion of a study between reviewers. Randomized controlled trials as well as cross-sectional studies published in English 10 years before May 2021 that investigate the neurophysiological adaptations in the brain and spinal cord in people with cerebral palsy will be included if they meet the eligibility criteria. Primary outcomes will include scalar values of fractional anisotropy (FA), H-reflex gains or measures of amplitude, as well as motor cortex (M1) cortical excitability as measured by transcranial magnetic stimulation. Discussion: Since no identifiable data will be involved in this study, no ethical approval is required. Our results will provide insight into the neurophysiological adaptations in children with cerebral palsy, which will be useful in guiding directions for clinical decision making and future development of targeted interventions in pediatrics rehabilitation for children with cerebral palsy. Systematic review registration: The protocol for this systematic review is registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration number: CRD42020215902).

The current study investigated the acoustic emission (AE) behaviour of a single pit evolution on two types of stainless steels using small-scaled electrodes. Dozens of AE signals were observed during pitting on 17-4 PH. However, 304 SS was much less acoustically emissive. According to the in-situ optical observation, black flocculent clusters were observed in 17-4 PH during pitting. However, such process was very weak in 304 SS. It was found that the hydrogen bubble formed inside the pit and the perturbation of electrolyte around the pit were able to create AE signals.

The Laves phase precipitates in ASTM A335 P92 (P92) steel were found to dissolve in solutions with NaOH concentration higher than 7 mol l−1. Such behaviour was utilized to detect and quantify the precipitates in P92 specimens aged at 650 °C for times from 0 to 5000 h. The amount of precipitates was acquired by potentiodynamically polarizing the sample and integrating the dissolution current over time. The result was compared to that of a traditional SEM observation method, and a good linear correlation was found between the results. The dissolution mechanism was discussed based on the electrochemical behaviour of an artificially synthesized Fe2Mo laves phase specimen, pure Fe, and pure Mo in the strong alkaline solution.

The effects of alternating dissolved oxygen (DO) and dissolved hydrogen (DH) on the corrosion behavior of Alloy 52 are studied by electric/electrochemical methods measured in situ including contact electric resistance (CER) and electrochemical impedance measurements (EIS) together with multiple ex-situ surface analysis techniques including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The film resistance changes cyclically in both DO and DH cycles. In DO cycle film resistance decreases with the increase of corrosion potential (Ecorr) while in DH cycle film resistance shows an opposite trend. The preformed oxide film in a low DO condition can suppress the oxidation rate in middle DO condition, whilst a high DO level can deteriorate the protectiveness of Cr enriched layer. In the DH cycle, the immersion in a low DH condition can increase the resistance in the following high DH condition. All the results indicate the characteristic of oxide formed in one water chemistry is highly influenced by the pre-immersion history, which should be paid much attention in the study of DO or DH effects on the properties of the oxide film and stress corrosion cracking (SCC) initiation.

Sound and sound frequency could improve postural sway in the elderly. The power spectrum intervals of the center of pressure (COP) displacement are associated with different postural regulations, which could be revealed by frequency analysis. The aim of the study was to investigate the effects of sound on dual-tasking postural control and conduct frequency analysis to distinguish postural regulations in the elderly. Fifteen young and 15 older healthy participants were instructed to stand on a force platform and performed the Purdue Pegboard test while hearing 50 dB sounds with sound frequencies of 250 Hz, 1000 Hz, 4000 Hz, or no sound. The total excursion, velocity, sway area, and power spectrum of low-, medium-, and high-frequency bands of the COP displacement were calculated in the anterior&ndash, posterior and medial&ndash, lateral directions. The percentages of low-frequency and medium-frequency bands in both directions were significantly different between with and without sound conditions, but not affected by sound frequency. Older adults showed a smaller percentage of low-frequency, larger percentage of medium-frequency, larger total COP excursion, and faster velocity in the medial&ndash, lateral direction. The outcome of the study supports the frequency analysis approach in evaluating sound effects on postural strategies in dual-tasking and reveals older adults utilize vestibular regulation as the primary postural strategy when the dual-task required visual attention.

This paper addresses the optimal operation issues for virtual power plant (VPP). Two conflicting objectives are considered and a bi-objective problem is formulated mathematically. The first objective (economical performance) contains cost of fuel consumption and cost of power purchased from grid. The second objective (environmental performance) takes account of several pollutant emissions. Multi-objective particle swarm optimization (MOPSO) is applied to derive the Pareto frontier which is a set of noninferior solutions. A realistic case study is performed on Hongfeng Eco-town as a model of VPP, which includes various distributed energy resources (DER) such as hydropower units, wind turbines, photovoltaic panels, combined cooling heating and power units (CCHP) and storage devices. Simulation concentrates on three strategies: 1) money-oriented, 2) environment-only, 3) Pareto-optimal. Comparison of simulation results reveals that Pareto-optimal strategy can better compromise costs and emissions. Further, system operators could choose noninferior solutions from Pareto frontier according to their specific preference.

This paper deals with the optimal dispatch of distributed energy resources (DERs) in a day-ahead electricity market. A virtual power plant (VPP) is established to integrate various DERs, especially to coordinate electric vehicles (EVs) and batteries to compensate the uncertainty of wind/solar power. Two objectives, cost of VPP and demand fluctuation, are respectively normalized to aggregate a bi-objective optimization problem. The multi-start memetic algorithm enhanced with local search is adopted as a solving technique. Three cases are investigated in numerical simulation: 1) EV random charging, 2) no EV cooperation, 3) all EVs cooperation. Computational results verify that the derived optimal strategy significantly reduces the load fluctuation and the cost of VPP. Sensitivity analysis on the weight factor reveals its impact on the dispatch performance.

Using the SDSS spectra of quasars included in the DR7Q or DR12Q catalogs, we search for Mg II narrow absorption doublets in the spectra data around Mg II emission lines. We obtain 17,316 Mg II doublets, within the redshift range of 0.3299 6000 km/s. If associated Mg II absorbers are defined by v_r < 6000 km/s, ~33.3% of the absorbers supposed to be contaminants of intervening systems. Removing the 33.3% contaminants, ~4.5% of the quasars present at least one associated Mg II system with W_r\lambda2796>=0.2 ��. The fraction of associated Mg II systems with high velocity outflows correlates with the average luminosities of their central quasars, indicating a relationship between outflows and the quasar feedback power. The v_r distribution of the outflow Mg II absorbers is peaked at 1023 km/s, which is smaller than the corresponding value of the outflow C IV absorbers. The redshift number density evolution of absorbers (dn/dz) limited by v_r > -3000 km/s differs from that of absorbers constrained by v_r > 2000 km/s. While, absorbers limited by v_r > 2000 km/s and higher values exhibit similar profile of dn/dz. In addition, the dn/dz is smaller when absorbers are constrained with larger v_r. The distributions of equivalent widths, and the ratio of W_r\lambda2796/W_r\lambda2803 is the same for associated and intervening systems, and independent on quasar luminosity., 8 pages, 8 figures. Accepted by ApJS

An active distribution system power-supply planning model considering cooling, heating and power load balance is proposed in this paper. A regional energy service company is assumed to be in charge of the investment and operation for the system in the model. The expansion of substations, building up distributed combined cooling, heating and power (CCHP), gas heating boiler (GHB) and air conditioner (AC) are included as investment planning options. In terms of operation, the load scenarios are divided into heating, cooling and transition periods. Also, the extreme load scene is included to assure the power supply reliability of the system. Numerical results demonstrate the effectiveness of the proposed model and illustrate the economic benefits of applying distributed CCHP in regional power supply on investment and operation.

Voluntary pushing or translation perturbation of the support surface each induces a body perturbation that affects postural control. The objective of the study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments when pushing an object (that induces self-initiated perturbation) and standing on a sliding board (that induces translational perturbation). Thirteen healthy young participants were instructed to push a handle with both hands while standing on a sliding board that was either free to move in the anterior–posterior direction or stationary. Electromyographic activity (EMG) of trunk and lower extremity muscles, center of pressure (COP) displacements, and the forces exerted by the hand were recorded and analyzed during the APA and CPA phases. When the sliding board was free to move during pushing (translation perturbation), onsets of activity of ventral leg muscles and COP displacement were delayed as compared to pushing when standing on a stationary board. Moreover, magnitudes of shank muscle activity and the COP displacement were decreased. When pushing heavier weight, magnitudes of muscle activity, COP displacement, and pushing force increased. The magnitude of activity of the shank muscles during the APA and CPA phases in conditions with translational perturbation varied with the magnitude of the pushing weight. The outcome of the study suggests that the central nervous system prioritizes the pushing task while attenuates the source of additional perturbation induced by translation perturbation. These results could be used in the development of balance re-training paradigms involving pushing weight while standing on a sliding surface.

In this Letter, we report the discovery of a strong correlation between the variability of narrow absorption lines (NALs) and the ionizing continuum from a two-epoch spectra sample of 40 quasars containing 52 variable C iv {\lambda}{\lambda}1548; 1551 absorption doublets. According to the concordance index, this sample is classified into two subsamples. Subsample I shows an anti-correlation between the variations of absorption lines and the continuum, while Subsample II exhibits a positive correlation. These results imply that these variable C iv {\lambda}{\lambda}1548; 1551 absorption doublets are intrinsic to the corresponding quasars and that their variations are caused primarily by the fluctuations of the ionizing continuum. Based on our analysis, we propose that there might be two kinds of absorption gas: one that is very sensitive to the continuum variations, the another that is not. In addition, we suggest that in many cases the emergence or disappearance of NALs is caused by fluctuations of the ionizing continuum., Comment: 6 pages, 2 figures

Water solution of organic amine is used widely for removing acid gases, especially for CO2. Some water solution of amines have the property of thermally induced phase transition at the temperature of cloud point at which the solution becomes turbid. The energy consumption could be reduced with the assistance of phase transition during the process of desorption. Therefore, it is important to discover the relationship between absorption and desorption capacity of amines and its property of thermally induced phase transition. In this work, hexylamine with the property of phase transition at cloud point and butylamine without the property were selected to perform the comparative experiment of CO2absorption and desorption at 30-100°C. Results show that 40% water solution of hexylamine and butylamine have similar CO2absorption capacity, and the change of CO2absorption capacity of hexylamine at cloud point is not obvious. Thus it is concluded that the property of thermally induced phase transition of hexylamine would not increase its CO2absorption capacity.

This paper presents the Component-Based Software Engineering (CBSE) approach for usability testing of a web-site based on ISO 9241-11 usability guidance to achieve specified goals with effectiveness, efficiency and satisfaction. Usability testing is a technique used to evaluate a product by testing it on users. A particular type of website i.e. university web site was chosen and segmented in different components in modular forms according to the purpose of that component. Then component wise tasks as per ISO 9241-11 usability guidance were prepared to carry out the usability testing for evaluating the test web-site. After analyzing the results of component based usability testing, a proto-type version of the test web-site was designed in a limited form including all the feedback of test results. Finally, the proto-type web-site was re-evaluated for establishing the effectiveness of component based web usability method with the same tasks. The proposed component based usability testing method is expected to improve the design/content issues of web-site resulting the web-site much more user friendly, effective and less time and cost consuming.

Following stroke, hemiparesis results in impaired motor control. Specifically, inappropriate direction of foot-forces during locomotion has been reported. In our previous study ( Liang and Brown 2011 ) that examined poststroke foot-force direction during a seated, supported locomotor task, we observed that foot-force control capabilities were preserved poststroke. In this current study, we sought to better understand the mechanisms underlying the interaction of locomotor and postural control as an interactive mechanism that might interfere, poststroke, with appropriate foot-force generation. We designed an experiment in which participants performed biomechanically controlled locomotor tasks, under posturally challenged pedaling conditions while they generated mechanical output that was comparable to pedaling conditions without postural challenge, thus allowing us to monitor the strategies that the nervous system adopts when postural conditions were manipulated. We hypothesized that, with postural influence, individuals poststroke would generate inappropriate shear forces accompanied by inappropriate changes to muscle activity patterns when performing a mechanically controlled locomotor task, and would be exaggerated with increased postural loading. Sixteen individuals with chronic poststroke hemiparesis and 14 age-similar nonimpaired controls pedaled on a cycle ergometer under 1) seated supported and 2) nonseated postural loaded pedaling conditions, generating matched pedal force outputs of two effort levels. When we compared postural influence with seated pedaling, we observed increased magnitudes of forward-directed shear forces in the paretic legs associated with increased magnitude of leg extensor muscle activity, but not in controls. These findings provide evidence to support a model that describes independent controllers for posture and locomotion, but that the interaction between the two controllers is impaired poststroke.

Objective To investigate the possibility of restoring the adapted spinal circuit after spinal cord injury (SCI) by means of long-term continuous passive motion (CPM) of the ankle joint. Design Randomized controlled trial with repeated measures. Setting Research laboratory in a general hospital. Participants Individuals with motor complete SCI (N=14) were recruited from a community. Intervention CPM of the ankle joint for 1 hour a day, 5 days a week for 4 weeks. Main Outcome Measures Modified Ashworth Scale (MAS) scores for evaluation of spasticity and postactivation depression (PAD) were documented prior to and after intervention. Results MAS scores improved after 4 weeks of CPM intervention, indicating a reduction in spasticity of the ankle joint. PAD was restored after 4 weeks of training. Conclusions Passive motion of the ankle joint alone was sufficient in reversing the adapted spinal circuit, and therefore indicates that spasticity after SCI could possibly be managed by CPM intervention. The results of this study support the use of the passive mode of robot-assisted therapy for humans with complete SCI who cannot exercise actively.

Battlefield environment information have multi-dimensional, multi-scale, multi-temporal state characteristics. Particle system is an effective method for three-dimensional battlefield meteorological environment and combat effects of visualization, can effectively organize, thereby efficiently Multidimensional Dynamic visualize the battlefield weather information. In this paper, the transmitter and influencers to build a common mode particle system, the model system consists of a particle emitter, particle renderer, particle control, particle composition manager, via a transmitter, controller interaction between each particle simulation kinds of changes in motion to improve the authenticity and versatility of the particle system, and through the model to achieve a three-dimensional battlefield meteorological environment and explosions and other special effects visualization.

Heritage includes the legacy in the past, what we live with today, and what we pass on to future generations. Our cultural and natural heritage are both irreplaceable sources of life and inspiration. There are many introductions about World Heritage on the Internet, especially the official website of United Nations Educational Scientific and cultural organization (UNESCO), which provides the authoritative and comprehensive data of world heritage. It is usually the most popular platform to obtain world heritage information. Combining world heritage with the WikiGlobe (a Digital Earth platform), a scene mode was set from a global perspective with more vivid presentation. This was one of the innovation points of this research. Compared with the traditional 2D display, WikiGlobe has a significant 3D visual effect and various visual tools. Based on WikiGlobe, this research focused on the characteristics of data, organization management and approaches of visualization and realized multi-information navigation and interaction mechanism. In addition, a dynamic mechanism of data maintenance has been established to achieve effective management and visualization of heritage data.

Objective Successful execution of upright locomotion requires coordinated interaction between controllers for locomotion and posture. Our earlier research supported this model in the non-impaired and found impaired interaction in the post-stroke nervous system during locomotion. In this study, we sought to examine the role of the Ia afferent spinal loop, via the H-reflex response, under postural influence during a locomotor task. We tested the hypothesis that the ability to increase stretch reflex gain in response to postural loads during locomotion would be reduced post-stroke. Methods Fifteen individuals with chronic post-stroke hemiparesis and 13 non-impaired controls pedaled on a motorized cycle ergometer with specialized backboard support system under (1) seated supported, and (2) non-seated postural-loaded conditions, generating matched pedal force outputs of two levels. H-reflexes were elicited at 90°crank angle. Results We observed increased H-reflex gain with postural influence in non-impaired individuals, but a lack of increase in individuals post-stroke. Furthermore, we observed decreased H-reflex gain at higher postural loads in the stroke-impaired group. Conclusion These findings suggest an impaired Ia afferent pathway potentially underlies the defects in the interaction between postural and locomotor control post-stroke and may explain reduced ability of paretic limb support during locomotor weight-bearing in individuals post-stroke. Significance These results support the judicious use of bodyweight support training when first helping individuals post-stroke to regain locomotor pattern generation and weight-bearing capability.

A multi-stage Active Distribution Network (ADN) planning model that integrated with the application of Energy Storage System (ESS) is presented in this paper. Both the longterm investment cost and short-term operation conditions of ADN are considered in the proposed model. The benefits of power supply reliability improvement brought by ESS in the ADN are also included. In each planning stage, the operation conditions are divided into several typical-day scenes and an extreme scene based on the load prediction data. The long-term expansion planning decisions including replacing and adding circuits, building up ESS, the short-term operation strategies of the ADN about charging and discharging ESS are optimized together in the model. The benefits of ESS, such as peak load shifting and power reliability enhancement are discussed based on some numerical cases, in which the centralized or distributed ESS become the options of ADN construction. Thus, the effectiveness of the proposed model is also demonstrated.

With the reform of electrical market, the application of demand-side management or demand response has been widely researched. The large elasticity of electricity price enables a more flexible control strategy in load-side. In this paper, the basic features of flexible loads including continuous and discrete loads or interruptible or notinterruptible loads will be analysed and modelled. Besides, all constrains concerning the behaviour of power consumption have been brought up. Next, an optimal control strategy oriented to minimum the energy expenditure of a typical home would be established and elaborated. Finally, a study case would be applied to validate the efficiency of the theory. The newly proposed method will be in the end validated by the on-site project of the National High-tech R&D Program (863 Program) in Guizhou Province, China.

Active distribution network (ADN), which is characterized by high penetration of distributed generation (DG) has often appeared reverse power across voltage grades, which leads to unsafe operation. In this paper, ADN is divided into regions based on switches location and region consumption capacity is proposed to obtain regional power flow from now on period of time by using ultra-short-term forecasting. According to the situation awareness results of consumption capacity, this paper highlights three renewable energy active consumption modes including local level consumption, feeder level consumption (intra-feeder and inter-feeder) and substation level consumption. Active local level and intra-feeder level consumption mode control DG output by index of feeder control error (FCE). Active inter-feeder level and substation level consumption mode operate switches based on optimal consumption capacity. Active consumption, which adds the control of DGs and switches, will achieve more efficient and stable operation and the ability of accommodate renewable energy will be improved. The effectiveness and validity of ADN active consumption modes is verified by the simulation of study case.

The interconnection of Distributed Energy Resource (DER) changes the network operation and power flow of traditional power distribution network and in some circumstances even leads to the malfunction of protection and automation in distribution network. Under such condition, the improvement of Feeder Automation (FA) is to correspond to the effects of the interconnection of distributed energy resource in power system. Smart distributed fault location and recovery method is presented in this paper. By proposing the process to realize fault isolation through the differential-activated algorithm based on synchronous sampling, framework of fault recovery is established for distribution network with DER. Fault isolation algorithm is proposed to meet multi-connected and multi-branch distribution network with distributed energy resource. Finally, the effectiveness of this algorithm is verified via both computer simulation and dynamic simulation of distributed power system with distributed energy resource in actual power network within the National 863 Program of China.

This paper surveys the research of the information fusion approaches based on game theory. How to resolve the high level fusion problem in the conflict and cooperation environment of multiple sources information is a key problem in the current research of information fusion. Game theory is promising to successfully model conflict and cooperative interactions. So, the relatively new interdisciplinary study of information fusion based on game theory deserves further exploration. Based on the state-of-the-art of the game-theoretic information fusion study, this paper analyzes the two characters (interdisciplinary and high-level) and two study routes (direct route and indirect route via Artificial Intelligence). The most representative processing models, architectures and algorithms in this field are described. The military and several civilian applications and the validity of the game-theoretic information fusion approaches are summarized. Finally, the issues and challenges are summarized and the further research directions are discussed.

Epidemiologic studies have shown an independent and definite association between obstructive sleep apnea (OSA) and hypertension. This study aimed to define the association between daytime blood pressure and severity of OSA in Chinese population in mainland of China.Twenty university hospital sleep centers in mainland of China were invited by the Chinese Medical Association (CMA) to participate in this epidemiologic study and 2297 consecutive patients (aged 18 - 85 years; 1981 males and 316 females) referred to these twenty sleep centers for evaluation of OSA between January 2004 and April 2006 were prospectively enrolled. Nocturnal polysomnography was performed in each patient, and disease severity was assessed based on the apneahypopnea index (AHI). These patients were classfied into four groups: nonapneic control (control, n = 257) with AHIor = 5 episodes/hour; mild sleep apnea (mild, n = 402) with AHI5 andor = 15 episodes/hour; moderate sleep apnea (moderate, n = 460) with AHI15 andor = 30 episodes/hour and severe sleep apnea (severe, n = 1178) with AHI30 episodes/hour. Daytime blood pressure measurements were performed under standardized conditions in each patient at 10 a.m. in office on the day of referring to sleep centers for getting average value. All the patients were requested to quit medications related to blood pressure for three days before the day of assessing.Both daytime systolic blood pressure and diastolic blood pressure values were significantly related to AHI positively (r = 0.201 and 0.276, respectively; both P values0.001) and to nadir nocturnal oxygen saturation negatively (r = -0.215 and -0.277, respectively; both P values0.001), which were the parameters of OSA severity. In two special designed mean plots, means of daytime systolic and diastolic blood pressure increased gradually with increasing AHI. Beyond AHI of 61 - 65, this increasing trend reached a plateau.The results showed that OSA severity was associated with daytime blood pressure until AHI of 61 - 65, providing evidence for early OSA management, especially in OSA patients with concomitant hypertension.

Situation assessment (SA) is one of the important processes in military decision. As a component of battlefield data fusion and decision support, SA is not easy to be realized ideally by using one particular technology in practice. Like any other complex military process, it requires the cooperation of lots of information processing technology. This paper describe a mechanism for constructing probabilistic models to represent and analyze uncertainties and assessing battlefield state based on a hierarchical distributed fusion processing of incoming information which can help commanders and analysts to model and assess the dynamic evolving situational state easily. We adopted a hierarchy distributed DBN model which can process information hierarchically and cooperatively through higher-level dynamic Bayesian networks and distributed lower-level dynamic Bayesian networks. And a 3-layer distributed computation environment is also introduced. The hierarchy distributed DBN can generate an accurate and efficient assessment of the battlespace and suitable for military hierarchical organizations.

In this paper, we propose a security evaluation model for the web application and define a security evaluation function based on the Analytic Hierarchy Process (AHP) to describe the model. We use the evaluation method proposed by this paper to evaluate the vulnerability test effect of a BBS application named IPB. The experiment result reveals that the evaluation value calculated by the security evaluation function is positively correlated with the number of vulnerabilities found in the security test. It proves that the security evaluation method proposed by this paper is practical and reliable.