Accurate Electroadhesion Force Measurements of Electrostrictive Polymers: The Case of High Performance Plasticized Terpolymers

Electroadhesion is a phenomenon ruled by many characteristic intrinsic parameters. To achieve a good adhesion, efficient and durable, a particular attention must be provided to the adhesion forces between the involved parts. In addition to the size and geometry of electrodes, parameters of materials such as dielectric constant, breakdown electric field, and Young’s modulus are key factors in the evaluation of electroadhesion efficiency for electrostrictive polymers and electroactive devices. By analyzing these material parameters, a method is proposed to justify the choice of polymer matrices that are fit to specific electroadhesion applications. Another purpose of this work aims to demonstrate a possibility of accurately measuring the electroadhesion force. This physical parameter has been usually estimated through equations instead, because of the complexity in setup implementation to achieve highly precise measure. Comparisons based on the parameters criterion reveal that besides the intrinsic properties of material, some other parameters relating to its physical phenomena (e.g., saturation of dipolar orientation under high electric field leads to decrease dielectric constant), or physical behavior of the system (i.e., surface roughness reduces the active electrode area) must be thoroughly considered. Experimental results pointed out that plasticized terpolymer leads boosted electroadhesion performance compared to the other counterparts, up to 100 times higher than conventional polymers. The developed materials show high potential in applications of active displacement control for electrostrictive actuation.

Measuring Polarization in Online Debates

Social networks can be a very successful tool to engage users to discuss relevant topics for society. However, there are also some dangers that are associated with them, such as the emergence of polarization in online discussions. Recently, there has been a growing interest to try to understand this phenomenon, as some consider that this can be harmful concerning the building of a healthy society in which citizens get used to polite discussions and even listening to opinions that may be different from theirs. In this work, we face the problem of defining a precise measure that can quantify in a meaningful way the level of polarization present in an online discussion. We focus on the Reddit social network, given that its primary focus is to foster discussions, in contrast to other social networks that have some other uses. Our measure is based on two different characteristics of an online discussion: the existence of a balanced bipartition of the users of the discussion, where one partition contains mainly users in agreement (regarding the topic of the discussion) and the other users in disagreement, and the degree of negativity of the sentiment of the interactions between these two groups of users. We discuss how different characteristics of the discussions affect the value of our polarization measure, and we finally perform an empirical evaluation over different sets of Reddit discussions about diverse classes of topics. Our results seem to indicate that our measure can capture differences in the polarization level of different discussions, which can be further understood when analyzing the values of the different factors used to define the measure.

Association Between Posture and Quality of Life: Implications for Children with Cancer

Background: Children with cancer experience decreased quality of life. The National Institutes of Health has recommended examination of quality of life factors to promote development of clinical interventions to reduce suffering. Measuring quality of life in children based on self-report instruments is limited by subjectivity, age, and developmental stage. Assessment of posture is a pioneering objective physical measure that may augment quality of life preceptions among individuals with cancer. Procedure: This systematic literature review synthesized published evidence regarding the relationship between posture and quality of life. A systematic search using PRISMA guidelines identified articles describing studies of human subjects that included the variables of a) posture measured by the standard thoracic kyphosis angle; and b) quality of life or depression/mood. A total of 14 eligible studies met inclusion criteria (published 2000-2018). Studies were graded for level of evidence and themes were identified. Results: No studies were found in children with cancer. The majority of the studies (8 of 14) were rated at the moderate level. Key review findings include evidence supporting: 1) a consistent bidirectional relationship between posture and quality of life; 2) that when posture improves, quality of life also increases; and when depression decreases, posture improves; and 3) emotion is expressed through posture. Conclusion: If posture is a sensitive and precise measure of quality of life, it could strengthen existing measurements and give a more complete picture to in turn identify children who may benefit from supportive care interventions during cancer treatment.

Pain expectation and avoidance in the social context: an electrophysiological study

Contingent negative variation (CNV) is an informative electrophysiological measure of pain anticipation showing higher amplitudes when highly painful stimulation is expected while presenting lower amplitudes when low painful stimulation is expected. Two groups of participants were recruited: one group expected and received an electrical stimulation of different intensities while being alone in the room (i.e. without social context), while a second group performed the same experiment with an observer in the room (i.e. with social context). Lower pain ratings and slower reaction times were observed in the group with social context and these results were accompanied in this group by a lower amplitude in the early component of the CNV as well as a lower amplitude of the later component of the wave. These results show that CNV can be considered a precise measure of central elaboration of pain anticipation explaining both its perceptual and motor components.

Performance Evaluation of Solar PV Power Plants in Taiwan Using Data Envelopment Analysis

Due to the worldwide impact of industrialization, renewable sources of energy from solar play a huge role in supplying the domestic demand in Taiwan. This paper aims to impart an unbiased performance evaluation of different solar photovoltaic (PV) power plants around Taiwan. This study utilized data envelopment analysis (DEA) using the epsilon-based measure (EBM) model to compute the performance efficiency and ranking of the solar PV power plants. Additionally, the model is used for its advantage of combined radial and non-radial measures to achieve a more precise measure of efficiency. The results show that among nine selected solar PV plants, the top-performing DMU was I (8200051) from the southern part of Taiwan. Therefore, this study recommends that EBM can be a useful tool to evaluate the performance of solar PV power plants using multiple inputs and outputs. Additionally, this study will contribute to sustaining and developing the existing solar PV power capacity while achieving the installation of 20GW of solar energy as part of Taiwan’s goal. Even though the study has achieved the set goals, various restrictions remain present. Future studies could address micro and macro-level factors that influence the performance of solar PV power plants, which are not included in this study.

Why We Should Use the Gini Coefficient to Assess Punctuated Equilibrium Theory

Punctuated Equilibrium Theory posits that policy-making is generally characterized by long periods of stability that are interrupted by short periods of fundamental policy change. The literature converged on the measure of kurtosis and L-kurtosis to assess these change patterns. In this letter, we critically discuss these measures and propose the Gini coefficient as a (1) comparable, but (2) more intuitive, and (3) more precise measure of “punctuated” change patterns.

Lost in Time: Temporal Monitoring Elicits Clinical Decrements in Sustained Attention Post-Stroke

Objectives: Mental fatigue, ‘brain fog’, and difficulties maintaining engagement are commonly reported issues in a range of neurological and psychiatric conditions. Traditional sustained attention tasks commonly measure this capacity as the ability to detect target stimuli based on sensory features in the auditory or visual domains. However, with this approach, discrete target stimuli may exogenously capture attention to aid detection, thereby masking deficits in the ability to endogenously sustain attention over time. Methods: To address this, we developed the Continuous Temporal Expectancy Task (CTET) where individuals continuously monitor a stream of patterned stimuli alternating at a fixed temporal interval (690 ms) and detect an infrequently occurring target stimulus defined by a prolonged temporal duration (1020 ms or longer). As such, sensory properties of target and non-target stimuli are perceptually identical and differ only in temporal duration. Using the CTET, we assessed stroke survivors with unilateral right hemisphere damage (N = 14), a cohort in which sustained attention deficits have been extensively reported. Results: Stroke survivors had overall lower target detection accuracy compared with neurologically healthy age-matched older controls (N = 18). Critically, stroke survivors performance was characterised by significantly steeper within-block performance decrements, which occurred within short temporal windows (˜3 ½ min), and were restored by the break periods between blocks. Conclusions: These findings suggest that continuous temporal monitoring taxes sustained attention processes to capture clinical deficits in this capacity over time, and outline a precise measure of the endogenous processes hypothesised to underpin sustained attention deficits following right hemisphere stroke.

Measuring Repurchase Decisions by Accelerating Repurchase Behavior

Repurchase intention questions are routinely used in marketing research and practices to measure consumers’ repurchase decisions. They are easy to use but suffer from a few biases and weak predictive power. This article identifies three biases, namely, projection bias, lack-of-context bias, and hypothetical bias. A new method, repurchase acceleration (RA), is proposed targeting these biases. In RA, researchers buy back respondents’ currently owned products to ensure they are in the market, provide them with a representative choice set to mimic the repurchase market context, and attach real-life consequences to mimic the incentives in their real-life repurchases. An empirical study demonstrates that RA predicts significantly better than repurchase intention models and captures more than 3 times as much information as the best repurchase intention model does. We recommend that RA is used for high-value, long purchase-cycle products for a precise measure of consumers’ repurchase decisions for high-stake marketing decisions.

How Should Performance Signals Affect Contracts?

The informativeness principle states that a contract should depend on informative signals. This paper studies how it should do so. Signals indicating that the output distribution has shifted to the left (e.g., weak industry performance) reduce the threshold for the manager to be paid; those indicating that output is a precise measure of effort (e.g., low volatility) decrease high thresholds and increase low thresholds. Surprisingly, “good” signals of performance need not reduce the threshold. Applying our model to performance-based vesting, we show that performance measures should affect the strike price, rather than the number of vesting options, contrary to practice.