Postural Analysis on Manual Pine Resin Collecting Work: Lifting Index and L5/S1 Compression-Shear Forces

Even though pine oleoresin harvesting is labor-intensive forestry work involving manual material handling (especially lifting) and is massively carried out in Indonesia, there is a lack of ergonomics studies on manual pine oleoresin harvesting. This study focused on lifting-related postures in pine oleoresin harvesting. A Three Dimension Static Strength Prediction Program Version 7.1.0 was used to identify the injury risk on the lower back (lumbosacral joint, L5/S1) using biomechanical criteria (compression and shear forces) at extreme postures. Recommended Weight Limit (RWL) and Lifting Index (LI) were calculated for a comprehensive analysis. The exceeding compression and shear forces indicated that the L5/S1 injury risk on oleoresin collecting work (part of oleoresin harvesting) is high. The psychophysical analysis confirmed the findings, as several main postures in this work were categorized as intense manual lifting due to the excessive score of LI. A significant reduction in the L5/S1 compression and shear forces were shown at a simulation using a proposed load threshold (using the calculated RWL). Keywords: biomechanics, ergonomics, forestry work, manual lifting, oleoresin harvesting

Noradrenergic deficits contribute to apathy in Parkinson's disease through the precision of expected outcomes

Apathy is a debilitating feature of many diseases, including Parkinson's disease. We tested the hypothesis that degeneration of the locus coeruleus-noradrenaline system contributes to apathy by modulating the relative weighting of prior beliefs about action outcomes. Participants with mild-to-moderate idiopathic Parkinson's disease (N=17) completed a double-blind, placebo-controlled, crossover study with 40 mg of the noradrenaline reuptake inhibitor atomoxetine. Prior weighting was inferred from psychophysical analysis of performance in an effort-based visuomotor task, and was confirmed as negatively correlated with apathy. Locus coeruleus integrity was assessed in vivo using magnetisation transfer imaging at 7T. The effect of atomoxetine depended on locus coeruleus integrity: participants with a more degenerate locus coeruleus showed a greater increase in prior weighting on atomoxetine versus placebo. The results indicate a contribution of the noradrenergic system to apathy and potential benefit from noradrenergic treatment of people with Parkinson's disease, subject to stratification according to locus coeruleus integrity.

Color discriminability makes over-specification efficient: Theoretical analysis and empirical evidence

A psychophysical analysis of referential communication establishes a causal link between a visual stimulus and a speaker’s perception of this stimulus, and between the speaker’s internal representation and their reference production. Here, I argue that, in addition to visual perception and language, social cognition plays an integral part in this complex process, as it enables successful speaker-listener coordination. This pragmatic analysis of referential communication tries to explain the redundant use of color adjectives. It is well documented that people use color words when it is not necessary to identify the referent; for instance, they may refer to “the blue star” in a display of shapes with a single star. This type of redundancy challenges influential work from cognitive science and philosophy of language, suggesting that human communication is fundamentally efficient. Here, I explain these seemingly contradictory findings by confirming the visual efficiency hypothesis: redundant color words can facilitate the listener’s visual search for a referent, despite making the description unnecessarily long. Participants’ eye movements revealed that they were faster to find “the blue star” than “the star” in a display of shapes with only one star. A language production experiment further revealed that speakers are highly sensitive to a target’s discriminability, systematically reducing their use of redundant color adjectives as the color of the target became more pervasive in a display. It is concluded that a referential expression’s efficiency should be based not only on its informational value, but also on its discriminatory value, which means that redundant color words can be more efficient than shorter descriptions.

Cognitive and Emotional Aspects of Cupping Therapy

Cupping therapy has recently gained public attention and is widely used in many regions. Some patients are resistant to being treated with cupping therapy, as visually unpleasant marks on the skin may elicit negative reactions. This study aimed to identify the cognitive and emotional components of cupping therapy. Twenty-five healthy volunteers were presented with emotionally evocative visual stimuli representing fear, disgust, happiness, neutral emotion, and cupping, along with control images. Participants evaluated the valence and arousal level of each stimulus. Before the experiment, they completed the Fear of Pain Questionnaire-III. In two-dimensional affective space, emotional arousal increases as hedonic valence ratings become increasingly pleasant or unpleasant. Cupping therapy images were more unpleasant and more arousing than the control images. Cluster analysis showed that the response to cupping therapy images had emotional characteristics similar to those for fear images. Individuals with a greater fear of pain rated cupping therapy images as more unpleasant and more arousing. Psychophysical analysis showed that individuals experienced unpleasant and aroused emotional states in response to the cupping therapy images. Our findings suggest that cupping therapy might be associated with unpleasant-defensive motivation and motivational activation. Determining the emotional components of cupping therapy would help clinicians and researchers to understand the intrinsic effects of cupping therapy.

Telehaptic Perception of Delayed Stiffness Using Adaptive Impedance Control: Experimental Psychophysical Analysis

Telehaptics is the science of transmitting touch-related sensations over computer networks. With respect to robot teleoperation, telehaptics emphasizes more on reliably reproducing physical properties of a remote environment, as mediated over a network through the use of appropriate haptic interfacing technologies. One of the main factors that can cause degradation of the quality of a telehaptic system is the presence of time delays. Inspired by concepts such as impedance-reflection and model-mediated telemanipulation, an adaptive impedance control scheme has been proposed aiming to mitigate some of the problems caused by network delays in a telehaptic system. This paper presents an experimental analysis, which has been conducted to assess the actual performance of the proposed telehaptic scheme in terms of both control and human perception objectives. Firstly, a set of comparative numerical experiments is presented aiming to analyze stability and characterize transparency of the telehaptic system under large time delays. The results show the superior performance of the proposed adaptive impedance scheme as compared to direct force-reflecting teleoperation. Then, a series of psychophysical experiments is described, to evaluate the performance of the telehaptic system with respect to human perception of remote (delayed) stiffness. An analysis of the obtained results shows that the proposed adaptive scheme significantly improves telehaptic perception of linear stiffness in the presence of network delays, maintaining perceptual thresholds close to the ones obtained in the case of direct, nondelayed stimuli. A comparative experimental evaluation of psychometric transparency confirms the superior robustness with regard to time delay of the adaptive impedance telehaptic scheme as compared to state-of-the-art position/force transparentizing methods.