An investigation of lower extremity energy dissipation strategies during single-leg and double-leg landing based on sagittal and frontal plane biomechanics

There is limited understanding of the differences in lower extremity energy dissipation strategies between single-leg and double-leg landing maneuvers. This study sought to investigate these differences in sagittal and frontal planes, and explain the differences using kinematics and kinetics. We hypothesized that single-leg and double-leg landing maneuvers involve different lower extremity energy dissipation strategies in both planes. Ten recreational athletes were recruited and instructed to perform double-leg and single-leg landing from 0.60-m height. Force-plates and motion-capture system were used to obtain kinetics and kinematics data respectively. Joint power was taken as product of joint moment and angular velocity. Joint work was computed as integral of joint power over time, whereby negative work represented energy dissipation. In the sagittal plane, the hip and knee showed major contributions to energy dissipation during double-leg landing; the hip and ankle were the dominant energy dissipaters during single-leg landing. In the frontal plane, the hip acted as the key energy dissipater during double-leg landing; the knee contributed the most energy dissipation during single-leg landing. The knee also exhibited greater frontal plane joint ROM, moment and energy dissipation during single-leg landing than double-leg landing. Our findings indicated that different energy dissipation strategies were adopted for double-leg and single-leg landing in sagittal and frontal planes. Considering the prominent frontal plane biomechanics exhibited by the knee during single-leg landing, we expect that this maneuver may have greater likelihood of leading to traumatic knee injuries, particularly non-contact ACL injuries, compared to the double-leg landing maneuver.     

Duplex decomposition and general segregation of lotteries of a gain and a loss: An empirical evaluation

We investigate the empirical validity of two hypotheses, duplex decomposition (DD) and general segregation (GS), regarding decomposition of a binary gamble of a gain and a loss into two unitary gambles in which one consequence of each gamble is no change from the status quo. Four binary lotteries (money gambles with specified probabilities) and four decomposed lotteries designed to test GS and four decomposed lotteries to test DD were constructed, and certainty equivalents (CEs) were estimated for each lottery. Respondents’ indifference between a binary lottery and a decomposed lottery was determined by evaluating the equality between the CE of a mixed binary lottery and the CE of the corresponding decomposed lottery. Given the variability of estimates of CEs and the lack of a clear statistical definition for the equality between two CEs, we applied several criteria: we counted responses where the difference between two CEs was either ±2% (the strictest criterion), ±4%, ±6%, or ±8% (the most lenient criterion) of the range of lottery outcomes. The results showed that under the strictest criterion, GS held for 25% of the responses and DD for 22%. Under the most lenient criterion, GS held for 56% of the responses and DD for 52%. Depending upon the criterion used, between 39 and 75% of the responses were consistent with at least one of the hypotheses. Several methodological problems in determining the indifference between two lotteries are discussed.     

Rhythm typology of Korean speech

According to their rhythmic properties, spoken languages have been classified by linguists into three categories, i.e. stress-timed, syllable-timed and mora-timed. Recently, this intuitive classification has been confirmed valid with perceptual studies. These studies have shown that both newborn infants and adults, upon hearing the pure rhythms of certain languages, are only able to discriminate between languages of the different categories mentioned above. These results indicate that the capacity of the categorization of the human cognitive system makes possible the classification of language that is not yet explored rhythmically. Here, we investigate the Korean spoken language through the adults discrimination tasks with resynthesized speech. Experimental results indicate that the Korean language is, like Japanese, one of the mora-timed languages.     

Risk and Protective Processes Predicting Rural African American Young Men's Substance Abuse

Informed by a life course perspective, this study tested a cascade model linking harsh, unresponsive parenting during childhood to young African American men's substance abuse via precocious transitions, economic instability, and future orientation. The moderating influence of community disadvantage and romantic partner support on the hypothesized pathways was also examined. At the baseline, the sample included 505 African American men between ages 19 and 22 years from high‐poverty rural communities. Follow‐up data were collected 18 months after baseline. Using structural equation modeling, we identified harsh, unresponsive parenting influenced precocious transitions in adolescence, which in turn increased economic instability during young adulthood. Economic instability was associated with a reduction in future orientation, a proximal influence on increases in substance abuse. Also, residence in a disadvantaged community amplified the influence of precocious transitions on economic instability and the influence of economic instability on future orientation. Involvement with supportive romantic partnership evinced a protective effect, attenuating the influence of precocious transitions on economic instability and the influence of economic instability on a future orientation. This study expands understanding of young adults’ substance abuse by demonstrating the risk and protective processes linking substance abuse to developmental factors across childhood, adolescence, and young adulthood.     

Magnitude processing and complex calculation is negatively impacted by mathematics anxiety while retrieval‐based simple calculation is not

Mathematics anxiety (MA) refers to the experience of negative affect when engaging in mathematical activity. According to Ashcraft and Kirk (2001), MA selectively affects calculation with high working memory (WM) demand. On the other hand, Maloney, Ansari, and Fugelsang (2011) claim that MA affects all mathematical activities, including even the most basic ones such as magnitude comparison. The two theories make opposing predictions on the negative effect of MA on magnitude processing and simple calculation that make minimal demands on WM. We propose that MA has a selective impact on mathematical problem solving that likely involves processing of magnitude representations. Based on our hypothesis, MA will impinge upon magnitude processing even though it makes minimal demand on WM, but will spare retrieval‐based, simple calculation, because it does not require magnitude processing. Our hypothesis can reconcile opposing predictions on the negative effect of MA on magnitude processing and simple calculation. In the present study, we observed a negative relationship between MA and performance on magnitude comparison and calculation with high but not low WM demand. These results demonstrate that MA has an impact on a wide range of mathematical performance, which depends on one's sense of magnitude, but spares over‐practiced, retrieval‐based calculation.     

The Effects of Scrambling on Spanish and Korean Agrammatic Interpretation: Why Linear Models Fail and Structural Models Survive

Several models of comprehension deficits in agrammatic aphasia rely heavily on linear considerations in the assignment of thematic roles to structural positions (e.g., the Trace-Deletion Hypothesis, the Mapping Hypothesis, and the Argument-Linking Hypothesis). These accounts predict that constructions in languages with rules that affect syntactic structure but preserve relative linear order should be unimpaired. Other models [e.g., the Double-Dependency Hypothesis, (DDH)] do not resort to linearity but are purely structural in conception and therefore should be immune to word-order effects. We tested linear and nonlinear accounts with scrambling structures in Korean and topicalization structures in Spanish. The results are very clear. The (nonlinear) DDH is entirely compatible with the evidence, but the linear accounts are not.     

Analogical reasoning in working memory: Resources shared among relational integration,interference resolution,and maintenance

We report a series of experiments using a pictorial analogy task designed to manipulate relational integration, interference resolution, and active maintenance simultaneously. The difficulty of the problems was varied in terms of the number of relations to be integrated, the need for interference resolution, and the duration of maintenance required to correctly solve the analogy. The participants showed decreases in performance when integrating multiple relations, as compared with a single relation, and when interference resolution was required in solving the analogy. When the participants were required to integrate multiple relations while simultaneously engaged in interference resolution, performance was worse, as compared with problems that incorporated either of these features alone. Maintenance of information across delays in the range of 1-4.5 sec led to greater decrements in visual memory, as compared with analogical reasoning. Misleading information caused interference when it had been necessarily attended to and maintained in working memory and, hence, had to be actively suppressed. However, sources of conflict within information that had not been attended to or encoded into working memory did not interfere with the ongoing controlled information processing required for relational integration. The findings provide evidence that relational integration and interference resolution depend on shared cognitive resources in working memory during analogical reasoning.     

The unique consequences of feeling lucky: Implications for consumer behavior

Cognitive priming procedures were used to identify the unique effects that luck-related concepts have on consumer behavior. The effects of these concepts could theoretically influence behavior through the elicitation of positive affect or via temporary changes in participants' self representations of how lucky they feel. An initial experiment showed that priming Asian consumers with lucky numbers independently influenced both their perceptions of personal luck and the positive affect they reported experiencing. Subsequent experiments, however, showed that the effect of these primes on consumer behavior was mediated by momentary changes in how lucky people felt (i.e. changes in the self concept) rather than by the positive affect they were experiencing at the time. Exposing consumers to lucky numbers influenced their estimates of how likely they were to win a lottery (Experiment 2), their willingness to participate in such a lottery (Experiment 4), their evaluations of different promotional strategies (Experiment 3), and also the amount of money they were willing to invest in different financial options (Experiment 4). The effect of luck on behavior was also moderated by a person's regulatory focus.