1,658 research outputs found
Upper body balance control strategy during continuous 3D postural perturbation in young adults
We explored how changes in vision and perturbation frequency impacted upright postural control in healthy adults exposed to continuous multiaxial support-surface perturbation. Ten subjects were asked to maintain equilibrium in standing stance with eyes open (EO) and eyes closed (EC) during sinusoidal 3D rotations at 0.25 (L) and 0.50 Hz (H). We measured upper-body kinematics â head, trunk, and pelvis â and analyzed differences in horizontal displacements and roll, pitch, and yaw sways. The presence of
vision significantly decreased upper-body displacements in the horizontal plane, especially at the head level, while in EC the head was the most unstable segment. H trials produced a greater segment stabilization compared to L ones in EO and EC. Analysis of sways showed that in EO participants stabilized their posture by reducing the variability of trunk angles; in H trials a sway decrease for the examined segments was observed in the yaw plane and, for the pelvis only, in the pitch plane. Our results
suggest that, during continuous multiaxial perturbations, visual information induced: (i) in L condition, a continuous reconfiguration of multi-body-segments orientation to follow the perturbation; (ii) in H condition, a compensation for the ongoing perturbation. These findings were not confirmed in EC where
the same strategy â that is, the use of the pelvis as a reference frame for the body balance was adopted both in L and H
Technical quality assessment of an optoelectronic system for movement analysis
The Optoelectronic Systems (OS) are largely used in gait analysis to evaluate the motor performances of healthy subjects and patients. The accuracy of marker trajectories reconstruction depends on several aspects: the number of cameras, the dimension and position
of the calibration volume, and the chosen calibration procedure. In this paper we propose a methodology to evaluate the eects of the mentioned sources of error on the reconstruction of marker trajectories. The novel contribution of the present work consists in the dimension of the tested calibration volumes, which is comparable with the ones normally used in gait analysis; in addition, to simulate trajectories during clinical gait analysis, we provide non-default
paths for markers as inputs. Several calibration procedures are implemented and the same trial is processed with each calibration le, also considering dierent cameras congurations.
The RMSEs between the measured trajectories and the optimal ones are calculated for each comparison. To investigate the signicant dierences between the computed indices, an ANOVA analysis is implemented. The RMSE is sensible to the variations of the considered calibration volume and the camera congurations and it is always inferior to 43 mm
Walking the tightrope: Circular economy breadth and firm economic performance
The circular economy (CE) can bring benefits but also pitfalls to the production processes, affecting a firm's economic performance. Using data from European SMEs, we empirically investigate, from the perspective of self-determination theory, the extent to which the breadth of CE activities, that is, the number of CE activities undertaken by a firm, affects a firm's economic performance. Our study theorizes and shows that there is an inverted U-shaped effect brought about by the number of CE activities on economic performance. This research advances our scientific understanding of the CE and provides managers with suggestions on how to maximize the benefits generated by the CE in terms of economic performance by implementing the right amount of CE activities
Visitor-sensing: Involving the crowd in cultural heritage organizations
As organizations are increasingly involving individuals across their boundaries in the generation of new knowledge, crowd involvement can also be beneficial to cultural heritage organizations. We argue that in an "Open Innovation in Science" approach, visitors can contribute to generate new scientific knowledge concerning their behavior and preferences, by which museum managers can re-design the cultural offerings of their institutions in ways that generate major economic and social impacts. Accordingly, we advance visitor-sensing as a novel framework in which museum managers leverage digital technologies to collect visitors' ideas, preferences, and feedback in order to improve path design and the organization of artwork in exhibitions, and to shape a more satisfying museum experience for visitors. We contend that visitor-sensing has the potential to yield higher numbers of visitors, with positive impacts in terms of increased revenues and increased literacy of the general public, thus benefiting the economic and social sustainability of cultural organizations towards the achievement of the Sustainable Development Goals outlined in the Agenda 2030
Rethinking recognition: social context in adult life rather than early experience shapes recognition in a social wasp
Social recognition represents the foundation of social living. To what extent social recognition is hard-wired by early-life experience or flexible and influenced by social context of later life stages is a crucial question in animal behaviour studies. Social insects have represented classic models to investigate the subject, and the acknowledged idea is that relevant information to create the referent template for nest-mate recognition (NMR) is usually acquired during an early sensitive period in adult life. Experimental evidence, however, highlighted that other processes may also be at work in creating the template and that such a template may be updated during adult life according to social requirements. However, currently, we lack an ad hoc experiment testing the alternative hypotheses at the basis of NMR ontogeny in social insects. Thus, to investigate the mechanisms underlying the ontogeny of NMR in Polistes wasps, a model genus in recognition studies, and their different role in determining recognition abilities, we subjected Polistes dominula workers to different olfactory experiences in different phases of their life before inserting them into the social environment of a novel colony and testing them in recognition bioassays. Our results show that workers develop their NMR abilities based on their social context rather than through pre-imaginal and early learning or self-referencing. Our study demonstrates that the social context represents the major component shaping recognition abilities in a social wasp, therefore shedding new light on the ontogeny of recognition in paper wasps and prompting the reader to rethink about the traditional knowledge at the basis of the recognition in social insects. This article is part of the theme issue 'Signal detection theory in recognition systems: from evolving models to experimental tests'
HJB Equations and Stochastic Control on Half-Spaces of Hilbert Spaces
In this paper, we study a first extension of the theory of mild solutions for HamiltonâJacobiâBellman (HJB) equations in Hilbert spaces to the case where the domain is not the whole space. More precisely, we consider a half-space as domain, and a semilinear HJB equation. Our main goal is to establish the existence and the uniqueness of solutions to such HJB equations, which are continuously differentiable in the space variable. We also provide an application of our results to an exit-time optimal control problem, and we show that the corresponding value function is the unique solution to a semilinear HJB equation, possessing sufficient regularity to express the optimal control in feedback form. Finally, we give an illustrative example
Preference of Polistes dominula wasps for trumpet creepers when infected by Xenos vesparum: A novel example of co-evolved traits between host and parasite
Emotion Recognition Deficits in the Differential Diagnosis of Amnestic Mild Cognitive Impairment: A Cognitive Marker for the Limbic-Predominant Phenotype.
AbstractObjective:Late-onset amnestic mild cognitive impairment (aMCI) with long disease course and slow progression has been recently recognized as a possible phenotypical expression of a limbic-predominant neurodegenerative disorder. Basic emotion recognition ability crucially depending on temporo-limbic integrity is supposed to be impaired in this group of MCI subjects presenting a selective vulnerability of medio-temporal and limbic regions. However, no study specifically investigated this issue.Methods:Hereby, we enrolled 30 aMCI with a biomarker-based diagnosis of Alzheimer's disease (i.e., aMCI-AD, n = 16) or a biomarker evidence of selective medio-temporal and limbic degeneration (aMCI-mTLD, n = 14). Ekman-60 Faces Test (Ek-60F) was administered to each subject, comparing the performance with that of 20 healthy controls (HCs).Results:aMCI-mTLD subjects showed significantly lower Ek-60F global scores compared to HC (p = 0.001), whose performance was comparable to aMCI-AD. Fear (p = 0.02), surprise (p = 0.005), and anger (p = 0.01) recognition deficits characterized the aMCI-mTLD performance. Fear recognition scores were significantly lower in aMCI-mTLD compared to aMCI-AD (p = 0.04), while no differences were found in other emotions.Conclusions:Impaired social cognition, suggested by defective performance in emotion recognition tasks, may be a useful cognitive marker to detect limbic-predominant aMCI subjects among the heterogeneous aMCI population
Le basi neurali delle funzioni cognitive di alto livello: un programma possibile?
The technological developments of the methods of neuroimaging and, in particular, of the new methods of analysis of the dates based on the analysis of functional integration, allow to examine the most complex aspects of brainâs working, by avoiding the risk of a âneofrenologyâ. The most recent studies deal with aspect of brainâs working that are traditionally considered out of the neurosciences, such as the economic decision, the moral choices and the esthetic experience. Â
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