Roll-over characteristics of human walking on inclined surfaces

Roll-over characteristics of able-bodied human subjects walking on ramped surfaces were examined in this study. Ten subjects walked at their normal self-selected speed on a level surface, a 5-deg ramp, and a 10-deg ramped surface. Ramps were designed such that ground reaction forces and center of pressure of the ground reaction forces could be measured on their surfaces. This set-up facilitated calculation of the effective rockers that the ankle-foot (AF) and knee-ankle-foot (KAF) systems conformed to during single-limb stance (contralateral toe off to contralateral heel contact). Since our original "roll-over shapes" were characterized between heel contact and opposite heel contact, we label the shapes found during single-limb stance as "truncated roll-over shapes". We hypothesized that the ankle-foot system would adapt to the various surfaces, creating a roll-over shape that would change in orientation with different levels of inclination. The truncated AF roll-over shapes supported this hypothesis for uphill walking but did not support the hypothesis for downhill walking. However, truncated roll-over shapes of the KAF system did adjust their orientation to match both the positive and negative levels of surface inclination. In general, the ankle appears to be the main adapting joint when walking up inclined surfaces while the knee becomes important for the overall adaptation in downhill walking. Knowledge of physiological lower-limb roll-over characteristics on ramped surfaces may help in the development of biomimetic prostheses and orthoses that will automatically adapt to changes in walking surface inclination.     

False recognition of abstract versus common objects in older and younger adults: testing the semantic categorization account

Older adults often demonstrate higher levels of false recognition than do younger adults. However, in experiments using novel shapes without preexisting semantic representations, this age-related elevation in false recognition was found to be greatly attenuated. Two experiments tested a semantic categorization account of these findings, examining whether older adults show especially heightened false recognition if the stimuli have preexisting semantic representations, such that semantic category information attenuates or truncates the encoding or retrieval of item-specific perceptual information. In Experiment 1, ambiguous shapes were presented with or without disambiguating semantic labels. Older adults showed higher false recognition when labels were present but not when labels were never presented. In Experiment 2, older adults showed higher false recognition for concrete but not abstract objects. The semantic categorization account was supported.     

Variations in mood state as a function of a football season

Scores on the Profile of Mood States were collected from football players at a small university each week prior to a Saturday football contest. The scores were analyzed to assess whether mood varied as a function of the outcome of the previous week's game. Although the subjects' overall mood state was not influenced by the outcome of the games, scores on Tension, Vigor, Fatigue, and Confusion varied. Fatigue and Confusion were related to the outcomes of the games and gave partial support to the hypothesis that the players' mood would vary according to the outcome of the games played.     

Incremental exercise, plasma concentrations of catecholamines, reaction time, and motor time during performance of a noncompatible choice response time task

The primary purpose was to examine the effect of incremental exercise on a noncompatible response time task. Participants (N=9) undertook a 4-choice noncompatible response time task under 3 conditions, following rest and during exercise at 70% and 100% of their maximum power output. Reaction and movement times were the dependent variables. Maximum power output had been previously established on an incremental test to exhaustion. A repeated-measures multivariate analysis of variance yielded a significant effect of exercise intensity on the task, observation of the separate univariate repeated-measures analyses of variance showed that only movement time was significantly affected. Post hoc Tukey tests indicated movement time during maximal intensity exercise was significantly faster than in the other two conditions. The secondary purpose of the study was to assess whether increases in plasma concentrations of adrenaline and nor-adrenaline during exercise and power output would act as predictor variables of reaction and movement times during exercise. Catecholamine concentrations were based on venous blood samples taken during the maximum power output test. None of the variables were significant predictors of reaction time. Only power output was a significant predictor of movement time (R2 = .24). There was little support for the notion that peripheral concentrations of catecholamines directly induce a central nervous system response.     

An ESID Case Study at the Federal Level

The D (dissemination) phase of the ESID model has been often overlooked in our efforts to create innovative and widespread social change. The process of replicating successful social innovations is both a prerequisite for dissemination (in order to assess the consistency of effects) and an obvious outcome of a successful dissemination effort. Fidelity, the extent to which a replicated program is implemented in a manner consistent with the original program model, is an important dimension of replication. This study was designed to provide empirical data related to three questions. Can complex social programs be implemented with fidelity? How much fidelity is appropriate or desired? What are the organizational dynamics of adoption with fidelity? Data were collected from grantees of a national replication initiative funded by the Center for Substance Abuse Prevention. Data suggest that high fidelity can be achieved, at least in the context in which programs are mandated to do so as part of the funding agreement and are given technical assistance in achieving fidelity. Secondly, programs perceived high fidelity as having positive effects on the program and its participants, a finding consistent with a limited assessment of the relationship of program outcomes and fidelity. Finally, much was learned about the human and organizational dynamics of replicating with fidelity. Implications for policy and direction regarding replication are discussed.     

Storage of verbal associations is sufficient to activate the left medial temporal lobe

Neuroimaging studies have shown that memory encoding activates the medial temporal lobe (MTL). Many believe that these activations are related to novelty but it remains unproven which is critical - novelty detection or the rich associative encoding it triggers. We examined MTL activation during verbal associative encoding using functional magnetic resonance imaging. First, associative encoding activated left posterior MTL more than single word encoding even though novelty detection was matched, indicating not only that associative encoding activates the MTL particularly strongly, but also that activation does not require novelty detection. Moreover, it remains to be convincingly shown that novelty detection alone does produce such activation. Second, repetitive associative encoding produced less MTL activation than initial associative encoding, indicating that priming of associative information reduces MTL activation. Third, re-encoding familiar associations in a well-established way had a minimal effect on both memory and MTL activation, indicating that MTL activation reflects storage of associations, not merely their initial representation.     

Introduction

The papers contained here were presented to the 1992 Meeting of the Society for Exact Philosophy held at the University of Southwestern Louisiana. Hence this volume owes a debt to several people who helped to organise that meeting. Many thanks, then, to Leslie Schilling, Richard and Robin Blackwell, Shannon Tubbs, Ted Latiolais and Amanda LaFleur.     

Duration of failure,causal attributions for failure,and subsequent reactions

Subjects were given a preliminary problem solving task of either short or long duration, and were told that they could shorten the duration of aversive noise bursts by correctly solving the problems. They were then given false feedback that they had done either well or poorly on the problems. Two groups of failing subjects were given information designed to lead them to attribute failure to either lack of ability or a difficult task. Two additional groups received “success” or “failure” feedback without any attributional cues. Failure-induced stress was reported to be greater under short duration conditions than under long duration conditions, and increased to the extent that subjects were led to believe they were personally responsible for failure. Following the preliminary failure period, task performance in the same situation and task performance and persistence in a different situation were assessed. In each case, performance and persistence decreased (a) following short-duration failure when subjects were led to attribute failure to a difficult task, and (b) following long-duration failure when subjects were led to attribute failure to lack of ability. These results are discussed within a framework that emphasizes the role of casual attributions in mediating the effects of failure.     

Item level validity of the Devereux Elementary School Behavior Rating Scale

Using a random sample of children in grades one through six as well as a sample of children referred for social or emotional problems, the item level validity of the Devereux Elementary School Behavior Rating Scale was assessed. Results indicated that Devereux responses for normal children tended to be skewed, with the item means falling near the positive end of the response continuum and with narrow standard deviations. Item means in the referred sample were closer to the center of the distribution and tended to have larger standard deviations. When item-to-subscale correlations were considered, the Devereux items, in general, were significantly correlated with their home subscale. Thirty-two of the 45 items on the scale had home scale correlations that were significantly higher than any other subscale correlation for that item. K-R 20 coefficients for subscales ranged from .74 to .89. Because the 9 items that had very poor subscale correlations were clustered on 4 of the 11 original subscales, it was recommended that these subscales be eliminated. The result would be a 31-item scale that measures seven different factors.Authorship is equal.