Influence of delayed muscle reflexes on spinal stability: Model-based predictions allow alternative interpretations of experimental data

Model-based calculations indicate that reflex delay and reflex gain are both important for spinal stability. Experimental results demonstrate that chronic low back pain is associated with delayed muscle reflex responses of trunk muscles. The aim of the present study was to analyze the influence of such time-delayed reflexes on the stability using a simple biomechanical model. Additionally, we compared the model-based predictions with experimental data from chronic low back pain patients and healthy controls using surface-electromyography. Linear stability methods were applied to the musculoskeletal model, which was extended with a time-delayed reflex model. Lateral external perturbations were simulated around equilibrium to investigate the effects of reflex delay and gain on the stability of the human lumbar spine. The model simulations predicted that increased reflex delays require a reduction of the reflex gain to avoid spinal instability. The experimental data support this dependence for the investigated abdominal muscles in chronic low back pain patients and healthy control subjects. Reflex time-delay and gain dependence showed that a delayed reflex latency could have relevant influence on spinal stability, if subjects do not adapt their reflex amplitudes. Based on the model and the experimental results, the relationship between muscle reflex response latency and the maximum of the reflex amplitude should be considered for evaluation of (patho) physiological data. We recommend that training procedures should focus on speeding up the delayed reflex response as well as on increasing the amplitude of these reflexes.     

Animal-Assisted Therapy with Farm Animals for Persons with Psychiatric Disorders: Effects on Anxiety and Depression,a Randomized Controlled Trial

This study examined the effects of Animal-Assisted Therapy with farm animals during a 12 weeks' intervention on anxiety and depression among psychiatric patients by using a randomized controlled trial with a follow-up investigation at 6 months. Ninety adult patients were included, with 41 completers in the treatment group and 28 in the control group. Anxiety measured using Spielberger State Anxiety Inventory did not decrease significantly during the intervention for the treatment group but was significantly lower at follow-up compared with baseline (p = 0.002) and with the end of the intervention (p = 0.004). There was no significant change for the control group. Depression measured using Beck Depression Inventory was significantly lower at follow-up compared with baseline for both groups, but there were no significant differences between the groups.     

Are good students desirable friends? Evidence for friendship selection among elementary students / ¿Son los buenos estudiantes amigos deseables? Evidencia para la selección de amistad entre estudiantes de educación primaria

Abstract

This study assesses the relationship between friendship networks and academic performance among third graders from one school in Santiago, Chile. Longitudinal social network analysis (RSiena) was used to test whether friendship selection is driven by academic performance and if befriended peers tend to influence each other on their academic performance, including gender as a covariate. Results show a positive relationship between academic performance and number of friendship nominations received, and a higher probability of same-gender friendships. Students with higher academic achievement are more likely to be nominated as friends, especially by peers with lower academic achievement. These results suggest that elementary students value high performance as a desirable characteristic in their friends.     

Relationships Between Leader-Contingent and Non-contingent Reward and Punishment Behaviors and Subordinates’ Perceptions of Justice and Satisfaction, and Evaluation of the Moderating Influence of Trust Propensity, Pay Level, and Role Ambiguity

Purpose

This research evaluates how reward and punishment behaviors are related to employee satisfaction, and how perceptions of justice mediate the effects of these behaviors. This study also seeks to examine the connection between some boundary conditions and the efficacy of reward and punishment behaviors.

Design/Methodology/Approach

Data were collected using questionnaires, and hypotheses were tested using a sample of 3,065 managers from 41 business units.

Findings

We found that contingent financial and social rewards were positively related to fairness and satisfaction, whereas punishment behaviors exert a negative influence. Findings reveal that high-trust propensity and low-pay level strengthen the positive influence of rewards on distributive justice, whereas high role ambiguity increases the positive effect of reward behaviors and the negative influence of non-contingent punishment (NCP) on superior satisfaction.

Implications

This study provided evidence that using contingent rewards is more effective in promoting positive attitudes at work than using contingent punishments. Our findings add to the evidence that organizations would benefit from encouraging their managers to use financial and social rewards and reducing the administration of NCP among performing employees.

Originality/Value

This study represents a first attempt to examine an integrated model of the effects of reward and punishment behaviors. It also contributes to this field by empirically evaluating the impact of individual and situational boundary conditions in the efficacy of these leader behaviors.     

The epistemology of absence-based inference

Our main aim in this paper is to contribute towards a better understanding of the epistemology of absence-based inferences. Many absence-based inferences are classified as fallacies. There are exceptions, however. We investigate what features make absence-based inferences epistemically good or reliable. In Section 2 we present Sanford Goldberg’s account of the reliability of absence-based inference, introducing the central notion of epistemic coverage. In Section 3 we approach the idea of epistemic coverage through a comparison of alethic and evidential principles. The Equivalence Schema–a well-known alethic principle–says that it is true that $p$ if and only if $p$ . We take epistemic coverage to underwrite a suitably qualified evidential analogue of the Equivalence Schema: for a high proportion of values of $p$ , subject $S$ has evidence that $p$ due to her reliance on source $S^{*}$ if and only if $p$ . We show how this evidential version of the Equivalence Schema suffices for the reliability of certain absence-based inferences. Section 4 is dedicated to exploring consequences of the Evidential Equivalence Schema. The slogan ‘absence of evidence is evidence of absence’ has received a lot of bad press. More elaborately, what has received a lot of bad press is something like the following idea: absence of evidence sufficiently good to justify belief in $p$ is evidence sufficiently good to justify belief in $\sim p$ . A striking consequence of the Evidential Equivalence Schema is that absence of evidence sufficiently good to justify belief in p is evidence sufficiently good to justify belief in $\sim p$ . We establish this claim in Section 4 and show how this supports the reliability of an additional type of absence-based inference. Section 4 immediately raises the following question: how can we make philosophically good sense of the idea that absence of evidence is evidence of absence? We address this question in Section 5. Section 6 contains some summary remarks.     

First and second language in the brain: Neuronal correlates of language processing and spelling strategies

This study explores oscillatory brain activity by means of event-related synchronization and desynchronization (%ERS/ERD) of EEG activity during the use of phonological and orthographic-morphological spelling strategies in L2 (English) and L1 (German) in native German speaking children. EEG was recorded while 33 children worked on a task requiring either phonological or orthographic-morphological spelling strategies. L2 processing elicited more theta %ERS than L1 processing (particularly at bilateral frontal and right posterior parietal sites) which might suggest a stronger involvement of semantic encoding and retrieval of the less familiar L2. The highest level of theta %ERS was revealed for the orthographic-morphological strategy in L2 which might indicate a more intense way of lexical retrieval compared to the phonological strategy in L2 and the orthographic-morphological strategy in L1. Analyses moreover revealed that phonological processing (both in L1 and L2) was associated with comparatively strong left-hemispheric %ERD in the upper alpha frequency band.     

Lashing Out after Stewing over Public Insults: The Effects of Public Provocation,Provocation Intensity,and Rumination on Triggered Displaced Aggression

Four studies present the first evidence showing that public (vs. private) provocation augments triggered displaced aggression by increasing the perceived intensity of the provocation. This effect is shown to be independent of face‐saving motivation. Following a public or private provocation, Study 1 participants were induced to ruminate or were distracted for 20 min. They then had an opportunity to aggress against another person who either acted in a neutral or mildly annoying fashion (viz. triggering event). As expected, the magnitude of the greater displaced aggression of those who ruminated before the triggering event compared with those distracted was greater under public than private provocation. Study 2 replicated the findings of Study 1 and confirmed that public provocations are experienced as more intense. Studies 3 and 4 both manipulated provocation intensity directly to show that it mediated the moderating effect of public/private provocation found in Study 1. The greater intensity of a public provocation increases reactivity to a subsequent trigger, which in turn, augments triggered displaced aggression. Aggr. Behav. 39:13‐29, 2013. © 2012 Wiley Periodicals, Inc.