scholarly journals Application of a novel force-field to manipulate the relationship between pelvis motion and step width in human walking

2019 ◽  
Author(s):  
Lauren N. Heitkamp ◽  
Katy H. Stimpson ◽  
Jesse C. Dean
Keyword(s):  
Force Field ◽  
Clinical Intervention ◽  
Human Walking ◽  
Proof Of Concept ◽  
Step Width ◽  
Mode 2 ◽  
Partial Correlations ◽  
Neurological Injuries ◽  
The Relationship ◽  
Neurologically Intact

AbstractMotion of the pelvis throughout a step predicts step width during human walking. This behavior is often considered an important component of ensuring bipedal stability, but can be disrupted in populations with neurological injuries. The purpose of this study was to determine whether a novel force-field that exerts mediolateral forces on the legs can manipulate the relationship between pelvis motion and step width, providing proof-of-concept for a future clinical intervention. We designed a force-field able to: 1) minimize the delivered mediolateral forces (Transparent mode); 2) apply mediolateral forces to assist the leg toward mechanically-appropriate step widths (Assistive mode); and 3) apply mediolateral forces to perturb the leg away from mechanically-appropriate step widths (Perturbing mode). Neurologically-intact participants were randomly assigned to either the Assistive group (n=12) or Perturbing group (n=12), and performed a series of walking trials in which they interfaced with the force-field. We quantified the step-by-step relationship between mediolateral pelvis displacement and step width using partial correlations. Walking in the Transparent force-field had a minimal effect on this relationship. However, force-field assistance directly strengthened the relationship between pelvis displacement and step width, whereas force-field perturbations weakened this relationship. Both assistance and perturbations were followed by short-lived effects during a wash-out period, in which the relationship between pelvis displacement and step width differed from the baseline value. The present results demonstrate that the link between pelvis motion and step width can be manipulated through mechanical means, which may be useful for retraining gait balance in clinical populations.

scholarly journals Effects of targeted assistance and perturbations on the relationship between pelvis motion and step width in people with chronic stroke

2020 ◽  
Author(s):  
Nicholas K. Reimold ◽  
Holly A. Knapp ◽  
Alyssa N. Chesnutt ◽  
Alexa Agne ◽  
Jesse C. Dean
Keyword(s):  
Force Field ◽  
Chronic Stroke ◽  
Step Width ◽  
Foot Placement ◽  
After Effects ◽  
Minute Period ◽  
After Effect ◽  
Targeted Assistance ◽  
Future Work ◽  
The Relationship

AbstractBackgroundPeople with chronic stroke (PwCS) often exhibit a weakened relationship between pelvis motion and paretic step width, a behavior important for gait stabilization. We have developed a force-field able to manipulate this relationship on a step-by-step basis.ObjectiveThe objective of this study was to investigate the effects of a single exposure to our novel force-field on the step-by-step modulation of paretic step width among PwCS, quantified by the partial correlation between mediolateral pelvis displacement at the start of a step and paretic step width (step start paretic ρdisp).MethodsFollowing a 3-minute period of normal walking, participants were exposed to 5-minutes of either force-field assistance (n=10; pushing the swing leg toward a mechanically-appropriate step width) or perturbations (n=10; pushing the swing leg away from a mechanically-appropriate step width). This period of assistance or perturbations was followed by a 1-minute catch period to identify any after-effects, a sign of sensorimotor adaptation.ResultsWe found that assistance did not have a significant direct effect or after-effect on step start paretic ρdisp. In contrast, perturbations directly reduced step start paretic ρdisp (p=0.004), but were followed by an after-effect in which this metric was increased above the baseline level (p=0.02).ConclusionsThese initial results suggest that PwCS have the ability to strengthen the link between pelvis motion and paretic foot placement if exposed to a novel mechanical environment, which may benefit gait stability. Future work is needed to determine whether this effect can be extended with repeated exposure to force-field perturbations.

scholarly journals Altered active control of step width in response to mediolateral leg perturbations while walking

2019 ◽  
Author(s):  
Nicholas K. Reimold ◽  
Holly A. Knapp ◽  
Rachel E. Henderson ◽  
Landi Wilson ◽  
Alyssa N. Chesnutt ◽  
...  
Keyword(s):  
Force Field ◽  
Active Control ◽  
Repeated Exposure ◽  
Step Width ◽  
After Effects ◽  
Body Dynamics ◽  
Walking Balance ◽  
The Relationship ◽  
Minimal Evidence ◽  
Normal Relationship

AbstractDuring human walking, step width is predicted by mediolateral motion of the pelvis, a relationship that can be attributed to a combination of passive body dynamics and active sensorimotor control. The purpose of the present study was to investigate whether humans modulate the active control of step width in response to a novel mechanical environment. Participants were repeatedly exposed to a force-field that either assisted or perturbed the normal relationship between pelvis motion and step width, separated by washout periods to detect the presence of potential after-effects. As intended, force-field assistance directly strengthened the relationship between pelvis displacement and step width. This relationship remained strengthened with repeated exposure to assistance, and returned to baseline afterward, providing minimal evidence for assistance-driven changes in active control. In contrast, force-field perturbations directly weakened the relationship between pelvis motion and step width. Repeated exposure to perturbations diminished this negative direct effect, and produced larger positive after-effects once the perturbations ceased. Both of these results provide evidence of gradual changes in active control in response to perturbations. In the longer term, these methods may be useful for improving deficits in the active control of step width often observed among clinical populations with poor walking balance.

scholarly journals Fluid Cognitive Abilities Are Important for Learning and Retention of a New, Explicitly Learned Walking Pattern in Individuals After Stroke

2021 ◽  
pp. 154596832110010
Author(s):  
Margaret A. French ◽  
Matthew L. Cohen ◽  
Ryan T. Pohlig ◽  
Darcy S. Reisman
Keyword(s):  
Cognitive Abilities ◽  
Step Length ◽  
Cognitive Measures ◽  
Retention Models ◽  
Wechsler Memory Scale ◽  
Walking Pattern ◽  
Learning Principles ◽  
The Relationship ◽  
Sequential Regression ◽  
Neurologically Intact

Background There is significant variability in poststroke locomotor learning that is poorly understood and affects individual responses to rehabilitation interventions. Cognitive abilities relate to upper extremity motor learning in neurologically intact adults, but have not been studied in poststroke locomotor learning. Objective To understand the relationship between locomotor learning and retention and cognition after stroke. Methods Participants with chronic (>6 months) stroke participated in 3 testing sessions. During the first session, participants walked on a treadmill and learned a new walking pattern through visual feedback about their step length. During the second session, participants walked on a treadmill and 24-hour retention was assessed. Physical and cognitive tests, including the Fugl-Meyer-Lower Extremity (FM-LE), Fluid Cognition Composite Score (FCCS) from the NIH Toolbox -Cognition Battery, and Spatial Addition from the Wechsler Memory Scale-IV, were completed in the third session. Two sequential regression models were completed: one with learning and one with retention as the dependent variables. Age, physical impairment (ie, FM-LE), and cognitive measures (ie, FCCS and Spatial Addition) were the independent variables. Results Forty-nine and 34 participants were included in the learning and retention models, respectively. After accounting for age and FM-LE, cognitive measures explained a significant portion of variability in learning ( R2 = 0.17, P = .008; overall model R2 = 0.31, P = .002) and retention (Δ R2 = 0.17, P = .023; overall model R2 = 0.44, P = .002). Conclusions Cognitive abilities appear to be an important factor for understanding locomotor learning and retention after stroke. This has significant implications for incorporating locomotor learning principles into the development of personalized rehabilitation interventions after stroke.

Dichotomization, Partial Correlation, and Conditional Independence

1996 ◽  
Vol 21 (3) ◽  
pp. 264-282 ◽  
Author(s):  
András Vargha ◽  
Tamás Rudas ◽  
Harold D. Delaney ◽  
Scott E. Maxwell
Keyword(s):  
Conditional Independence ◽  
Partial Correlation ◽  
Statistical Significance ◽  
Conventional Wisdom ◽  
Predictor Variables ◽  
Lower Power ◽  
Partial Correlations ◽  
Current Article ◽  
The Difference ◽  
The Relationship

It was recently demonstrated that performing median splits on both of two predictor variables could sometimes result in spurious statistical significance instead of lower power. Not only is the conventional wisdom that dichotomization always lowers power incorrect, but the current article further demonstrates that inflation of apparent effects can also occur in certain cases where only one of two predictor variables is dichotomized. In addition, we show that previously published formulas claiming that correlations are necessarily reduced by bivariate dichotomization are incorrect. While the magnitude of the difference between the correct and incorrect formulas is not great for small or moderate correlations, it is important to correct the misunderstanding of partial correlations that led to the error in the previous derivations. This is done by considering the relationship between partial correlation and conditional independence in the context of dichotomized predictor variables.

scholarly journals Targeted Allele Replacement Mutagenesis of Corynebacterium pseudotuberculosis

2011 ◽  
Vol 77 (10) ◽  
pp. 3532-3535 ◽  
Author(s):  
Caray A. Walker ◽  
Willie Donachie ◽  
David G. E. Smith ◽  
Michael C. Fontaine
Keyword(s):  
Corynebacterium Pseudotuberculosis ◽  
Sequence Length ◽  
Homologous Sequence ◽  
Proof Of Concept ◽  
Rolling Circle Replication ◽  
Content Type ◽  
Rolling Circle ◽  
Allele Replacement ◽  
Marker Free ◽  
The Relationship

ABSTRACTA two-step allele replacement mutagenesis procedure, using a conditionally replicating plasmid, was developed to allow the creation of targeted, marker-free mutations inCorynebacterium pseudotuberculosis. The relationship between homologous sequence length and recombination frequency was determined, and enhanced plasmid excision was observed due to the rolling-circle replication of the mutagenesis vector. Furthermore, an antibiotic enrichment procedure was applied to improve the recovery of mutants. Subsequently, as proof of concept, a marker-free,cp40-deficient mutant ofC. pseudotuberculosiswas constructed.

MERGE OF THE TECHNİCAL ANALYSİS TYPES GİVES THE BEST RESULTS İN CRYPTOCURRENCY MARKET

2021 ◽  
Vol 6 (14) ◽  
pp. 89-97
Author(s):  
MUSTAFA ÖZYEŞİL ◽  
MOHAMMAD AL-TARIFI
Keyword(s):  
Supply And Demand ◽  
Investment Strategy ◽  
Proof Of Concept ◽  
Market Capitalization ◽  
Long Run ◽  
Peer Network ◽  
Tangible Asset ◽  
The Relationship ◽  
Peer To Peer Network

Cryptocurrencies are a modern kind of financial instrument (Hudson & Urquhart, 2019), the first cryptocurrency is Bitcoin , proposed by who called Satoushi Nakamato (2008), as The open source was created on the proof-of-concept principle that transactions can be securely treated on a decentralized peer to peer network without the need for a central clearinghouse, which appeared 2009 ( Heid, 2013). The success of the bitcoin blazes a trail to what called ‘Altcoin” this expression means all the cryptocurrencies that set in motion after the victory of the bitcoin, these coins sell themselves as the best alternatives for the bitcoin (FRANKENFIELD, 2020) . There are many types for the altcoin. The third type of the cryptocurrency is called Tokens Unlike Bitcoin and Altcoins, tokens are not able to activate independently and are dependent on the grid of another cryptocurrency. That means they do not have their own core DLT or blockchain, but instead, are built on top of an existing cryptocurrency’s blockchain (Types of cryptocurrencies: explaining the major types of cryptos, 2019). The worth of bitcoin doesn’t depend on any tangible asset or economies of the countries while it is based upon the security of an algorithm which traces all transactions (Hudson & Urquhart, 2019). The studies determine the number of the bitcoin price development in the long -run (Ciaian, Rajcaniova, & Kancs, 2018): • Market forces of the Bitcoin supply and demand • The bitcoin’s attractiveness for the investors • The influence of global macro-financial developments If you're forming an investment strategy designed to help you trail long-term financial intentions, understanding the relationship between company size, return potential, and risk is vital. (Market cap—or market capitalization—refers to the total value of all a company's shares of stock, 2017) .Hence , Manifested importance a cryptocurrency’s market capitalization as the total values of all coins currently in circulation. the cryptocurrency’s market cap contains what’s called Bitcoin Dominance that is the ratio between the market cap of bitcoin to other coins of the cryptocurrency markets (jacobcanfield, 2019) . Cryptocurrency trade is attractive type of investment. this market treated the same of the foreign exchange and stock market ( Radityo, Munajat, & Budi, 2017). The investors using the same basic in investment (buy low, sell high) but they need to calculating the risks

S/G-1: An ab Initio Force-Field Blending Frozen Hermite Gaussian Densities and Distributed Multipoles. Proof of Concept and First Applications to Metal Cations

2014 ◽  
Vol 118 (35) ◽  
pp. 7598-7612 ◽  
Author(s):  
Robin Chaudret ◽  
Nohad Gresh ◽  
Christophe Narth ◽  
Louis Lagardère ◽  
Thomas A. Darden ◽  
...  
Keyword(s):  
Force Field ◽  
Ab Initio ◽  
Metal Cations ◽  
Proof Of Concept

Perceived Maternal Child-Rearing Behavior among Disabled and Non-Disabled Adolescents

1977 ◽  
Vol 44 (3_suppl) ◽  
pp. 1095-1105 ◽  
Author(s):  
Dennis C. Harper
Keyword(s):  
Maternal Behavior ◽  
Parental Behavior ◽  
Child Rearing ◽  
One Dimension ◽  
Severity Of Disability ◽  
The Disabled ◽  
Partial Correlations ◽  
Main Effects ◽  
The Impact ◽  
The Relationship

The purposes of this study were (a) to contrast the reported perceptions of maternal rearing using the Child's Report of Parental Behavior Inventory of 70 disabled (cerebral palsied) and 70 non-disabled adolescents of similar sex, age, intelligence, and socioeconomic status and (b) to evaluate the impact of severity of physical impairment within the disabled group. Analyses of variance were completed using group (disabled/controls) as one dimension and sex as the within-groups source. Partial correlations were used to assess the relationship between severity of incapacitation and perceived maternal behavior. Of the 18 main effects, two were significant, suggesting that the non-disabled perceived their mothers as more possessive and intrusive than did the disabled. Males perceived their mothers as significantly more lax in discipline and allowing more autonomy than did females. Severity of disability was only modestly related to perceived maternal behavior. With this sample of disabled adolescents it was suggested that a physically handicapping condition and its severity may be of more limited influence in the maternal rearing process than assumed.

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