Quadriceps Torque,Peak Variability and Strength Endurance in Patients after Anterior Cruciate Ligament Reconstruction: Impact of Local Muscle Fatigue

Abstract

We tested if ACL-reconstructed participants show a decreased quadriceps torque, a lower muscle endurance capacity and a higher peak torque variability compared to unimpaired control participants prior to and following local muscle fatigue. Participants (n?=?19, 10 women; 25?±?5yrs.) with unilateral hamstrings autograft ACL-reconstruction and a matched unimpaired control group were recruited. Participants performed two maximal isometric voluntary force (MIVF) contractions of the knee extensors. In between, standardized local muscle fatigue was induced. ACL-reconstructed knees display a lower peak torque of the knee extensors in comparison to the contralateral limb (3.2?±?.3Nm/kg vs. 3.5?±?.3 Nm/kg). Peak torque variability and fatigue resistance were not affected by local muscle fatigue (p > .05). Participants with ACL-reconstructed knees show a persistent quadriceps muscle dysfunction. This dysfunction and lower limb side asymmetries might be risk factors for ACL re-ruptures.     

Books Received

Leg-to-body ratio (LBR) is one of the morphological traits that influences a person's attractiveness. To date, studies confirming that hypothesis have been conducted mainly in Western cultures. They have shown that the average or slightly higher-than-the-average LBR is perceived to be attractive in women. In the case of men, results were more ambiguous; however generally shorter or similar LBRs compared to females were attractive. Here, data on LBR preferences of a traditional, semi-nomad ethnic group (i.e., the Himba of northern Namibia, n = 81) are reported. Also in Himba people LBR influences a person's attractiveness. Similar to Western societies, extremely high and low LBRs were unattractive. However, contrary to previous findings, Himba preferred women of relatively low LBR and men of relatively high LBR.     

Threat to Ethnic Identity: The Experience of White Afrikaans-Speaking Participants in Postapartheid South Africa

Abstract

The dismantling of apartheid and the postapartheid dispensation had far-reaching implications for all the citizens of South Africa. In an urban sample of White Afrikaans-speaking South Africans (Afrikaners) in postapartheid South Africa, the authors investigated perceptions of threat to ethnic identity, as well as correlates of those perceptions. The respondents experienced threat on 2 levels: The 1st was distinctive continuity, the concern that their ethnic group would not continue as a distinctive group in society. The 2nd was the evaluative dimension of ethnic identity (i.e., well-being), the concern that group membership would no longer contribute to positive self-esteem. The respondents experienced greater threat on the 2nd level, reflecting predominantly negative experiences as White Afrikaans-speaking persons in postapartheid South Africa. A high threat perception on the 2nd level was associated with (a) a perception of other groups' negative evaluations of their ethnic group, (b) negative attitudes toward political changes, and (c) perceptions of illegitimacy and instability of the postapartheid political system. The respondents who felt that Afrikaners would not continue as a distinctive group in society had a more positive attitude toward the sociopolitical changes, did not show strong ethnic identification, and had a negative collective self-esteem. They were also politically more liberal. Those findings are discussed in relation to theoretical expectations.     

Associations Between Religious Behavior and Attitude to Christianity Among Australian Catholic Adolescents: Scale Validation

Abstract

In a sample of 1,166 Catholic high school students (age = 13–18 years), the author used confirmatory factor analysis to validate a 30-item instrument that assesses 6 dimensions of attitude to Christianity (viz., attitude to prayer, attitude to God, attitude to Jesus, attitude to the Bible, attitude to Christian practice, attitude to social justice). Goodness-of-fit indices for the proposed measurement model revealed that the model fitted the data very well, thus confirming the instrument's structure. A correlation analysis revealed associations between religious behavior and attitude to Christianity.     

Ostracism drives group moralization and extreme group behavior

ABSTRACT

Sharing beliefs, particularly moral beliefs, is a way to establish social connections. We hypothesized that ostracism leads people who are high in the need to belong to adhere to the moral beliefs of an ingroup, and that moralizing the beliefs of one’s group increases the willingness to endorse extreme behavior on behalf of the group. Across two studies, participants were ostracized or included, rated the moral relevance of their group values, and indicated their endorsement of extreme behavior on behalf of the group. Across studies, ostracism increased group moralization in participants high in the need to belong. In Study 2, group moralization translated into endorsement of extreme behavior. Our findings suggest that morality serves a binding function that may be channeled into extreme behaviors. (120 words)     

RELATIONS AMONG ACUTE AND CHRONIC NICOTINE ADMINISTRATION,SHORT-TERM MEMORY,AND TACTICS OF DATA ANALYSIS

Emerging evidence suggests that nicotine may enhance short‐term memory. Some of this evidence comes from nonhuman primate research using a procedure called delayed matching‐to‐sample, wherein the monkey is trained to select a comparison stimulus that matches some physical property of a previously presented sample stimulus. Delays between sample stimulus offset and comparison stimuli onset are manipulated and accuracy is measured. The present research attempted to systematically replicate these enhancement effects with pigeons. In addition, the effects of nicotine were assessed under another, more dynamic, memory task called titrating‐delay matching‐to‐sample. In this procedure, the delay between sample offset and comparison onset adjusts as a function of the subject's performance. Correct matches increase the delay, mismatches decrease the delay, and titrated delay values serve as the primary dependent measure. Both studies examined nicotine's effects under acute and chronic administration. Neither provided clear or compelling evidence of memory enhancement following nicotine administration despite reliable and systematic dose‐related changes in response latency measures. A modest dose‐related effect on accuracy was found, but the magnitude of the effect appears to be directly related to tactics of data analysis involving best‐dose analyses of a very circumscribed subset of trial types.     

Effects of a meaningful, a discriminative, and a meaningless stimulus on equivalence class formation

Thirty college students attempted to form three 3-node 5-member equivalence classes under the simultaneous protocol. After concurrent training of AB, BC, CD, and DE relations, all probes used to assess the emergence of symmetrical, transitive, and equivalence relations were presented for two test blocks. When the A-E stimuli were all abstract shapes, none of 10 participants formed classes. When the A, B, D, and E stimuli were abstract shapes and the C stimuli were meaningful pictures, 8 of 10 participants formed classes. This high yield may reflect the expansion of existing classes that consist of the associates of the meaningful stimuli, rather than the formation of the ABCDE classes, per se. When the A-E stimuli were abstract shapes and the C stimuli became S(D)s prior to class formation, 5 out of 10 participants formed classes. Thus, the discriminative functions served by the meaningful stimuli can account for some of the enhancement of class formation produced by the inclusion of a meaningful stimulus as a class member. A sorting task, which provided a secondary measure of class formation, indicated the formation of all three classes when the emergent relations probes indicated the same outcome. In contrast, the sorting test indicated "partial" class formation when the emergent relations test indicated no class formation. Finally, the effects of nodal distance on the relatedness of stimuli in the equivalence classes were not influenced by the functions served by the C stimuli in the equivalence classes.     

EFFECTS OF A SIGNALED DELAY TO REINFORCEMENT IN THE PREVIOUS AND UPCOMING RATIOS ON BETWEEN-RATIO PAUSING IN FIXED-RATIO SCHEDULES

Domestic hens responded under multiple fixed‐ratio fixed‐ratio schedules with equal fixed ratios. One component provided immediate reinforcement and the other provided reinforcement after a delay, signaled by the offset of the key light. The components were presented quasirandomly so that all four possible transitions occurred in each session. The delay was varied over 0, 4, 8, 16, and 32 s with fixed‐ratio 5 schedules, and over 0, 8 and 32 s with fixed‐ratio 1, 15 and 40 schedules. Main effects of fixed‐ratio value and delay duration were detected on between‐ratio pauses. Pauses were longer when the multiple‐schedule stimulus correlated with a delayed‐reinforcer component was presented, with the longest pauses occurring at the transition from a component with an immediate reinforcer to one with a delayed reinforcer. Pause durations were shortest during immediate components. Overall, both the presence or absence of a delay in the upcoming component, and the presence or absence of a delay in the preceding component affected pause length, but the upcoming delay had the larger effect. Thus changes in delay had similar effects to past reports of the effects of changes in response force, response requirement, and reinforcer magnitude in multiple fixed‐ratio fixed‐ratio schedules.     

Facilitating and inhibiting effects of priming and selection criteria in a sequence of dichotic listening trials

Competing models of attention make different predictions of how priming from recent stimulus processing could interact with intended selection. The present experiment examined the interaction between exogenous attention and endogenous priming across trial sequences. A sound cue directed attention to left, right or both sides before a dichotic syllable pair was presented. Participants were asked to report one syllable from each trial. Results showed that responses were slower on trials where one of the presented syllables had also been presented on the previous trial. Within these trials, the repeated syllable was selected less frequently, and the responses doing so were slower. Examined according to response choice on the preceding trial, syllables that had been ignored on the preceding trial tended to be ignored on the current trial (negative priming), while syllables that had been selected on the preceding trial tended to be selected on the current trial (positive priming). Responses that followed these selection biases were faster than responses that did not. Response selection was also influenced by the attention direction cue for the current trial, but not by the cue presented on the preceding trial. The results support an attentional model where traces from the preceding processing are retained, and current selection is biased to minimize cognitive conflict between recent and current processing. Negative priming appears to be due to after-effects of preceding processing, independently of the intentions behind that processing. The study accounts for positive and negative priming of dichotic listening sequences within an established, computationally viable biased competition framework.     

Using a Training-of-Trainers Approach and Proactive Technical Assistance to Bring Evidence Based Programs to Scale: An Operationalization of the Interactive Systems Framework’s Support System

Bringing evidence based programs to scale was a major initial impetus for the development of the Interactive Systems Framework for Dissemination and Implementation (ISF). The ISF demonstrates the importance of the Support System in facilitating the uptake of innovations in the community (the Delivery System). Two strategies that members of the Support System commonly use are training‐of‐trainers (TOT) models and technical assistance (TA). In this article, we focus on the role of the Support System in bringing evidence‐based programs (EBPs) to scale in the Delivery System using a case example, with special attention on two strategies employed by Support Systems—training‐of‐trainers (TOT) and proactive technical assistance. We then report on findings from a case example from the Promoting Science Based Approaches to Teen Pregnancy Prevention project that furthers our conceptualization of these strategies and the evidence base for them. We also report on the limitations in the literature regarding research on TOTs and proactive TA and provide suggestions for future research on TOTs and proactive TA that will enhance the science and practice of support in the ISF. Special Issue: Advances in Bridging Research and Practice Using the Interactive System Framework for Dissemination and Implementation; Guest Editors: Abraham Wandersman, Paul Flaspohler, Catherine A. Lesesne, Richard Puddy; Action Editor: Emilie Phillips Smith