The nature of functional variability in plantar pressure during a range of controlled walking speeds

During walking, variability in step parameters allows the body to adapt to changes in substrate or unexpected perturbations that may occur as the feet interface with the environment. Despite a rich literature describing biomechanical variability in step parameters, there are as yet no studies that consider variability at the body–environment interface. Here, we used pedobarographic statistical parametric mapping (pSPM) and two standard measures of variability, mean square error (m.s.e.) and the coefficient of variation (CV), to assess the magnitude and spatial variability in plantar pressure across a range of controlled walking speeds. Results by reduced major axis, and pSPM regression, revealed no consistent linear relationship between m.s.e. and speed or m.s.e. and Froude number. A positive linear relationship, however, was found between CV and walking speed and CV and Froude number. The spatial distribution of variability was highly disparate when assessed by m.s.e. and CV: relatively high variability was consistently confined to the medial and lateral forefoot when measured by m.s.e., while the forefoot and heel show high variability when measured by CV. In absolute terms, variability by CV was universally low (less than 2.5%). From these results, we determined that variability as assessed by m.s.e. is independent of speed, but dependent on speed when assessed by CV

Methyl 3-[(E)-(2-hy­droxy-1-naphth­yl)methyl­idene]carbazate

The title compound, C13H12N2O3, has an E configuration with respect to the C=N bond: the conformation is stabilized by an intramolecular O—H⋯N hydrogen bond. In the crystal, an N—H⋯O interaction links the molecules into a C(4) chain along [100]

Ethyl 6-amino-8-(4-chloro­phen­yl)-9-nitro-2,3,4,8-tetra­hydro­pyrido[2,1-b][1,3]thia­zine-7-carboxyl­ate

In the structure of the title compound, C17H18ClN3O4S, the thia­zinane ring displays a twist-boat conformation. The 1,4-dihydro­pyridine ring is approximately perpendicular to the benzene ring [dihedral angle = 88.3 (1)°]. The mol­ecular conformation is stabilized by an intra­molecular N—H⋯O hydrogen bond. In the crystal, mol­ecules are linked by N—H⋯O inter­actions into a C(8) chain along [100]

Random walk of motor planning in task-irrelevant dimensions

The movements that we make are variable. It is well established that at least a part of this variability is caused by noise in central motor planning. Here, we studied how the random effects of planning noise translate into changes in motor planning. Are the random effects independently added to a constant mean end point, or do they accumulate over movements? To distinguish between these possibilities, we examined repeated, discrete movements in various tasks in which the motor output could be decomposed into a task-relevant and a task-irrelevant component. We found in all tasks that the task-irrelevant component had a positive lag 1 autocorrelation, suggesting that the random effects of planning noise accumulate over movements. In contrast, the task-relevant component always had a lag 1 autocorrelation close to zero, which can be explained by effective trial-by-trial correction of motor planning on the basis of observed motor errors. Accumulation of the effects of planning noise is consistent with current insights into the stochastic nature of synaptic plasticity. It leads to motor exploration, which may subserve motor learning and performance optimization

3-Chloro-4-hydroxy­furan-2(5H)-one

In the title compound, C4H3ClO3, mol­ecules are linked via O—H⋯O hydrogen bonds into an infinite chain with graph-set motif C(6) along the c axis

(E)-N′-(4-Nitro­benzyl­idene)-4-(8-quinol­yloxy)butano­hydrazide

In the title compound, C20H18N4O4, conformation along the bond sequence linking the benzene and quinoline rings, which have a mean inter­planar dihedral angle of 2.7 (5)°, is trans–(+)gauche–trans–trans–(−)gauche–trans–trans. In the crystal structure, a pair of inter­molecular N—H⋯O hydrogen bonds links the mol­ecules into centrosymmetric cyclic R 2 2(8) dimers, which are aggregated via π–π inter­actions into parallel sheets [quinoline–benzene ring centroid separation = 3.6173 (16)–3.6511 (16) Å]. The sheets are further connected through weak C—H⋯O inter­actions, giving a supra­molecular two-dimensional network

Reducing Versatile Bat Wing Conformations to a 1-DoF Machine

Recent works have shown success in mimicking the flapping flight of bats on the robotic platform Bat Bot (B2). This robot has only five actuators but retains the ability to flap and fold-unfold its wings in flight. However, this bat-like robot has been unable to perform folding-unfolding of its wings within the period of a wingbeat cycle, about 100 ms. The DC motors operating the spindle mechanisms cannot attain this folding speed. Biological bats rely on this periodic folding of their wings during the upstroke of the wingbeat cycle. It reduces the moment of inertia of the wings and limits the negative lift generated during the upstroke. Thus, we consider it important to achieve wing folding during the upstroke. A mechanism was designed to couple the flapping cycle to the folding cycle of the robot. We then use biological data to further optimize the mechanism such that the kinematic synergies of the robot best match those of a biological bat. This ensures that folding is performed at the correct point in the wingbeat cycle

Nodular Fasciitis with Cortical Erosion of the Hand

Nodular fasciitis is a benign, reactive myofibroblastic tumor that is often mistaken for a sarcoma because of its histological appearance and rapid growth. Involvement of a finger is extremely rare. We report a case of nodular fasciitis of the thumb, accompanied by bone erosion. Magnetic resonance findings suggested the possibility of a malignancy, which could have led to misdiagnosis as a malignant soft tissue sarcoma. Instead, the lesion was treated by excisional biopsy, which confirmed nodular fasciitis. There has been no evidence of local recurrence at recent follow-up, 1 year after surgery. This case illustrates that, to avoid unnecessarily aggressive surgery, nodular fasciitis must be included in the differential diagnosis for any finger lesion that resembles a sarcoma, even if bone erosion is present

Understanding key constraints and practice design in Rugby Union place kicking : experiential knowledge of professional kickers and experienced coaches

Place kicks present valuable opportunities to score points in Rugby Union, which are typically performed under varying constraints in competitive performance environments. Previous quantitative studies suggest these interacting constraints can influence fluctuations in place kick success. To further the understanding of how fluctuations in place kicking success emerge, our aim was twofold: i) to explore and identify the key constraints that professional place kickers and experienced place kicking coaches perceive to influence the difficulty of a place kick and ii) to understand the level to which current place kicking practice environments represent these key constraints experienced in performance environments. Six professional place kickers and six experienced place kicking coaches were interviewed. Using a deductive thematic analysis, 11 key constraints were identified: individual constraints of expectation for success and fatigue, task constraints of angle and distance to goalposts, environmental constraints of wind, weather, pitch, and crowd, and situational constraints of previous kicking performance, time remaining and current score margin. Place kicking is typically practised individually or with a small number of place kickers in isolation from team sessions. Where possible, coaches should be encouraged to include place kicking in simulated game scenarios during practice to represent key constraints from performance environments. Our study demonstrates how experiential knowledge can enrich the understanding of sport performance and inform the design of practice environments which simulate relevant constraints of competitive performance to enhance skill adaptation of athletes

The loyal dissident: N.A. Bernstein and the double-edged sword of Stalinism

Nikolai Aleksandrovich Bernstein (1896-1966) studied movement in order to understand the brain. Contra Pavlov, he saw movements (thus, the brain) as coordinated. For Bernstein, the cortex was a stochastic device; the more cortexes an animal species has, the more variable its actions will be. Actions are planned with a stochastic "model of the future," and relevance is established through blind mathematical search. In the 1950 neoPavlovian affair, he came under strong attack and had to stop experimenting. It is argued that the consistency of his work derived both from both dialectical materialism and the relentless attacks of the neoPavlovians. Copyright © Taylor & Francis Group, LLC