Center of Gravity Motions and Ankle Joint Stiffness Control in Upright Undisturbed Stance Modeled Through a Fractional Brownian Motion Framework

The authors modeled the center of gravity vertical projection (CG_V) and the difference, CP - CG_V, which, combined, constitute the center of pressure (CP) trajectory, as fractional Brownian motion in order to investigate their relative contributions and t heir spatiotemporal articulation. The results demonstrated that CG_V and CP - CG_V motions are both endowed in complementary tashion with strong stochastic and part-deterministic behaviors. In addition, if the temporal coordinates remain similar for all 3 trajectories by definition, the switch between the successive control mechanisms appears for shorter displacements for CP - CG_V and CG_V than for CP trajectories. Results deduced from both input (CG,) and muscular stiffness (CP - CG_V) thus provide insight into the way the central nervous system regulates stance control and in particular how CG and CP - CG are controlled.     

Age-Related Changes in Distance From Center of Mass to Center of Pressure During One-Leg Standing

ABSTRACT. The purpose of this study was to clarify the age-related effects of distances from the center of pressure (COP) to the center of mass (COM) (COP-COM distances) during one-leg standing (OLS) task. Healthy old and young adults (n = 11 each) participated in this study. The authors divided the task into 3 phases (accelerated, decelerated, and steady) based on the relationship between COM and COP. COP-COM distances in the older group were significantly reduced during the accelerated phase, then significantly increased during the decelerated and steady phases. Furthermore, distances during these phases correlated inversely with OLS time. The authors conclude that OLS time is shortened by the larger braking response to COM shifts just after leg-lifting, and the production of larger inertial forces to maintain COM position during the OLS in older individuals.     

Evaluating the Safety and Effectiveness of the Weighted Blanket With Adults During an Inpatient Mental Health Hospitalization

The weighted blanket (WB) is a modality used to self-comfort, rest, sleep, and decrease anxiety. This exploratory, pilot study investigates the safety and effectiveness of the standardized use of the 30-pound WB with 30 adults during an acute inpatient mental health hospitalization. Safety measures include blood pressure, pulse rate, and pulse oximetry monitoring, with and without the 30-pound WB. The State Trait Anxiety Inventory-10 (STAI-10), a self-rating 0–10 anxiety scale, and electrodermal activity (EDA) readings measure effectiveness for anxiety reduction. No statistical differences in vital signs indicate WB safety. The STAI-10 and self-ratings indicate 60% had a significant reduction in anxiety using the WB. EDA readings were inconclusive.     

Increased forefoot loading is associated with an increased plantar flexion moment

The aim of this study was to identify the cascade of effects leading from alterations in force generation around the ankle joint to increased plantar pressures under the forefoot. Gait analysis including plantar pressure measurement was performed at an individually preferred and a standardized, imposed gait velocity in diabetic subjects with polyneuropathy (n = 94), without polyneuropathy (n = 39) and healthy elderly (n = 19). The plantar flexion moment at 40% of the stance phase was negatively correlated with the displacement rate of center of pressure (r = ?.749, p < .001 at the imposed, and r = ?.693, p < .001 at the preferred gait velocity). Displacement rate of center of pressure was strongly correlated with forefoot loading (r = ?.837, p < .001 at the imposed, and r = ?.731, p < .001 at the preferred gait velocity). People with a relatively high plantar flexion moment at 40% of the stance phase, have a faster forward transfer of center of pressure and consequently higher loading of the forefoot. This indicates that interventions aimed at increasing the control of the roll-off of the foot may contribute to a better plantar pressure distribution.     

Sit-to-stand movement in children: A longitudinal study based on kinematics data

Although the ability to stand from a seated posture is relevant for clinical practice, there are few studies investigating the process of acquisition and refinement of the motor components involved in sit-to-stand movement (STS) in children. Therefore, this longitudinal study aims to describe kinematic characteristics of the STS movement in children from 12 to 18 months, and also to investigate the relationship between changes in STS movement and childrens’ daily-life mobility. Ten healthy children were evaluated at 12,13,14,15 and 18 months of age. A motion analysis system was used to measure total duration of STS movement and angular movements of each joint, and frequencies of successful and unsupported STS were obtained. The Pediatric Evaluation of Disability Inventory was used to assess childrens’ daily-life mobility. Results showed that children tend to increase the frequency of successful trials over the months by reducing the total duration and decreasing peak ankle dorsiflexion and trunk flexion during STS. Children also started to stand up from chair with decreased trunk flexion angle among ages. At the end of the STS, we observed decreases in trunk flexion and knee flexion over age. Furthermore, kinematic characteristics that reflect improvements in STS movement are related to better performance of functional skills and decreased level of assistance provided by the caregiver in daily-life mobility of younger children. However, the strength of these associations decreases from 14 months of age onwards.     

Positive Social Pressure and Prosocial Motivation: Evidence from a Large‐Scale Field Experiment on Voter Mobilization

Political scientists are increasingly exploring the psychological underpinnings of voting behavior using field experimental techniques. Research in psychology demonstrates that positive reinforcement—what I describe as positive social pressure—motivates prosocial behavior. A distinctive feature of the current study is the focus on key subgroups of voters, namely unmarried women and minorities. Attention to these voter subgroups allows us to build upon findings reported in previous studies that leave questions about the generalizability of the reported effects of positive social pressure to key demographic subgroups of voters largely unanswered. This article reports the results of a large‐scale randomized field experiment designed to investigate the impact of positive social pressure on voter turnout. The experiment was conducted during the November 2009 gubernatorial election in New Jersey, and the results suggest positive social pressure mobilizes voters. Moreover, the effects appear to be robust across subgroups of voters, including minorities and unmarried women, and both lower‐ and higher‐propensity voters.     

Task-load manipulation in the Symbol Digit Modalities Test: An alternative measure of information processing speed

ObjectiveTo evaluate the utility of an oral fMRI-adapted version of the Symbol Digit Modalities Test (SDMT) to assess information processing speed (IPS) using three different interstimulus intervals (ISI).MethodsNineteen right-handed healthy controls performed the adapted version of the SDMT, consisting of a block design that had a total of 6 control/activation block pairs with 3 different ISIs (1.5, 2 and 2.5 s) presented in two different runs: in ascending and descending orders. The brain activation patterns during different ISIs were assessed by effective functional connectivity analysis based on independent component analysis.ResultsAs expected, all conditions yielded activations in the fronto-parietal networks (FPNs) related to attention processes. Shorter ISIs (1.5 and 2 s) not only yielded greater patterns of connectivity within fronto-parietal and occipital regions such as the FPN and fronto-occipital network (FON), but also recruited more functional networks overall. Task performance at the shortest ISI was negatively correlated with connectivity at the FPN and activity of the pre-supplementary motor area extending to the cingulate gyrus.ConclusionIncreasing IPS demands due to shorter ISIs resulted in an increased level and number of functional networks required, increased connectivity within the FPN and FON, and enhancement of the prefrontal cortex. IPS does not arise from activity of a single b area but from affective information transfer among distant cortical regions of the frontal and parietal cortices. This adapted version of the SDMT may be useful for studying alterations of IPS in clinical and nonclinical populations.     

Ventral encoding of functional affordances: A neural pathway for identifying errors in action

Functional tool usage is a critical aspect of our daily lives. Not only must we know which tools to use for a specific action goal, we must also know how to manipulate those tools in meaningful way to achieve the goal of the action. The purpose of this study was to identify the regions of the brain critical to supporting the process of understanding errors in tool manipulation. Using fMRI, neural activations were recorded while subjects were presented with images demonstrating typical action scenes (screwdriver used on a screw), but with the tool being manipulated either correctly (screwdriver held by handle) or incorrectly (screwdriver held by bit rather than handle). Activations in fMRI for identifying correct over incorrect tool manipulation were seen along the canonical parietofrontal action network, while activations for identifying incorrect over correct tool manipulation were primarily seen at superior temporal areas and insula. We expand our hypotheses about ventral brain networks identifying contextual error to further suggest mechanisms for understanding functional tool actions, which collectively we regard as functional affordances. This proposes a fundamental role for ventral brain areas in functional action understanding.     

An examination of premarital sexual behavior among college students in hong kong

Abstract

This study examined the determinants of Hong Kong Chinese college students' intentions to engage in premarital sexual behavior. Fishbein and Ajzen's (1975) theory of reasoned action (TOFA) and Ajzen's (1985) perceived behavioral control were used as the theoretical framework for our investigation. Two hundred and thirty eight students completed a questionnaire designed to measure constructs of the two theories. Results from the regression analysis: (a) support the applicability of TORA in predicting these students' intentions to engage in premarital sex; (b) suggest that while attitudes toward engaging in premarital sex were more important in predicting male students' intentions, subjective norms were more important for female students; (c) reveal that the additional prediction contributed by the behavioral control components was relatively weak. Other findings were basically consistent with premarital sex research conducted in Western societies. Given the fact that promoting abstinence is one way to stop the transmission of the AIDS virus, both the theoretical and applied implications of our results for health intervention are discussed.     

Busy lifestyles and mammography screening: Time pressure and women’s reattendance likelihood

Time pressure is often cited as a reason for non-attendance at mammography screening, although evidence from other areas of psychology suggests that time pressure can improve performance when barriers such as time pressure provide a challenge. We predicted that time pressure would negatively predict attendance in women whose self-efficacy for overcoming time pressure is low, but positively predict attendance when self-efficacy is high. Time pressure was operationalised as the self-reported number of dependent children and others, and average number of working hours per week. Australian women were surveyed after being invited to attend second or subsequent screenings at a free public screening service, and subsequent attendance monitored until six months after screening was due. The majority (87.5%) attended screening. Women with more dependent children and higher self-efficacy showed greater attendance likelihood, and women with fewer non-child dependants and lower self-efficacy were less likely to attend. Working hours did not predict attendance. Findings provide partial support for the idea that time pressure acts as a challenge for women with high self-efficacy.