Force Increase in a Repetitive Motor Task Inducing Motor Fatigue

To evaluate task induced motor fatigue in a well-established finger tapping task, we analyzed tapping parameters and included the time course of measures of force. We hypothesized that a decline in tapping force would reflect task induced motor fatigue, defined by a lengthening of inter-tap intervals (ITI). A secondary aim was to investigate the reliability of tapping data acquisition with the force sensor. Results show that, as expected, tapping speed decreased linearly over time, due to both an increase of ITI and tap duration. In contrast, tapping force increased non-linearly over time and was uncorrelated to changes in tapping speed. Force data could serve as a measure to characterize task induced motor fatigue. Force sensors can assess a decline in tapping speed as well as an independent increase of tapping force. We argue that the increase of force reflects central compensation, i.e. perception of fatigue, due to an increase in task effort and difficulty.     

RESPONSIBILITY TO PROTECT AND MILITARIZED HUMANITARIAN INTERVENTION: When and Why the Churches Failed to Discern Moral Hazard

This essay addresses moral hazards associated with the emerging doctrine of the Responsibility to Protect (R2P). It reviews the broad acceptance by the Vatican and the World Council of Churches of the doctrine between September 2003 and September 2008, and attempts to identify grounds for more adequate investigation of the moral issues arising. Three themes are pursued: how a changing political context is affecting notions of sovereignty; the authority that can approve or refuse the use of force; and plural foundations for human rights in a religiously and otherwise plural world such that the human rights protection does not become tyrannical.     

Changes in Muscle Activity in Response to Assistive Force during Isometric Elbow Flexion

Abstract

This study investigated the muscle activity and force variability in response to perturbation of assistive force during isometric elbow flexion. Sixteen healthy right-handed young men (age: 22.0?±?1.1?years; height: 171.9?±?4.8?cm; weight 68.4?±?11.2?kg) were recruited and the muscle activity of biceps brachii and triceps brachii were assessed using surface electromyography. Workload force and assistive force applied on isometric elbow flexion significantly affected the changes in both biceps and triceps muscle activities. A higher assistive force was shown to result in reduced biceps muscle activity compared to the unassisted period. In contrast, the efficiency of the assistive force acting on the biceps decreased as the assistive force increased. In general, the force variability of the biceps muscle remained approximately the same at lower workload force conditions than that at higher workload force conditions. In conclusion, higher assistive force may not yield a higher performance efficiency in human-assistive force interaction.     

The meaning of service questionnaire and its association with psychological growth among Veterans

ABSTRACT

Few studies have investigated what soldiers find meaningful after being exposed to highly stressful events and what positive effects they might have in the aftermath. This study reports the psychometric properties of a newly developed questionnaire, Meaning of Service (MoS), and its application to the study of how strongly meaning-making processes are associated with psychological growth. One hundred eighty-four Norwegian Air Force Veterans who have participated in various missions abroad in different branches of the military completed the MoS questionnaire along with other scales reflecting psychological growth, hardiness, resilience, stress, and exposure, as well as personal and mission characteristics. The principal component analysis mainly identified three major meaning themes as expected from previous qualitative research (Confirmation of ability, Cohesion of peers, and Significance of effort). The hierarchical regression analysis showed that all three meaning themes and two coping strategies were associated with psychological growth, and that Confirmation of ability (coping and recognition of coping) seems particularly important to enhance Veterans’ prospects of psychological growth. Future research directions are proposed including suggestions for minor modifications of the questionnaire.     

武警某地区基层干部自我效能感研究

目的:探讨基层干部自我效能感的现状及其所呈现出的特点,为提升干部素质,提高管理水平提供参考。方法:采用标准问卷进行现场调查。结果:①基层干部的自我效能感在成长环境、是否独生、立功受奖等三个维度上没有显著差异;②基层干部的自我效能感在基层工作时间维度上有显著差异;③基层干部的自我效能感在成长环境和是否独生两个维度上的主效应和交互效应没有显著差异;④基层干部的自我效能感在基层工作时间和立功受奖两个维度上的交互效应没有显著差异。     

Grip Force-Load Force Coupling Is Influenced by Altered Visual Feedback about Object Kinematics

Abstract

Recent evidence suggests that visual feedback influences the adjustment of grip force to the changing load force exerted by a grasped object as it is manipulated. The current project investigated how visual feedback of object kinematics affects the coupling of grip force to load force by scaling the apparent displacements of the object viewed in virtual reality. Participants moved the object to manually track a moving virtual target. The predictability of the changing load force exerted by the object was also manipulated by altering the nature of target trajectories (and therefore the nature of object motions). When apparent object displacements increased in magnitude, grip force became more tightly coupled to load force over time. Furthermore, when load force variations were less predictable, the magnitude of apparent object displacements affected the relative degree of continuous versus intermittent coupling of grip force to load force. These findings show that visual feedback of object motion affects the ongoing dynamical coupling between grip force control and load force experienced during manipulation of a grasped object.     

Comparing stimulus preference and response force in a conjugate preparation

Researchers used a conjugate preparation to evaluate how response force changed based on participants' preferences for visual stimuli. First, researchers used a verbal preference assessment to evaluate each participant's preference for viewing for five object categories of visual stimuli; this process identified high preference (HP) stimuli and low preference stimuli for most participants. Thereafter, researchers exposed each participant to the five stimulus categories in a randomized order while using a force dynamometer to measure their response force to increase visual clarity of each stimulus. Results indicate the majority of participants' HP stimuli corresponded to the stimulus category for which they exerted the highest mean force. These preliminary findings suggest conjugate preparations involving response force may provide another option for measuring the relative value of some stimulus events.