Using dynamic walking models to identify factors that contribute to increased risk of falling in older adults

Falls are common in older adults. The most common cause of falls is tripping while walking. Simulation studies demonstrated that older adults may be restricted by lower limb strength and movement speed to regain balance after a trip. This review examines how modeling approaches can be used to determine how different measures predict actual fall risk and what some of the causal mechanisms of fall risk are. Although increased gait variability predicts increased fall risk experimentally, it is not clear which variability measures could best be used, or what magnitude of change corresponded with increased fall risk. With a simulation study we showed that the increase in fall risk with a certain increase in gait variability was greatly influenced by the initial level of variability. Gait variability can therefore not easily be used to predict fall risk. We therefore explored other measures that may be related to fall risk and investigated the relationship between stability measures such as Floquet multipliers and local divergence exponents and actual fall risk in a dynamic walking model. We demonstrated that short-term local divergence exponents were a good early predictor for fall risk. Neuronal noise increases with age. It has however not been fully understood if increased neuronal noise would cause an increased fall risk. With our dynamic walking model we showed that increased neuronal noise caused increased fall risk. Although people who are at increased risk of falling reduce their walking speed it had been questioned whether this slower speed would actually cause a reduced fall risk. With our model we demonstrated that a reduced walking speed caused a reduction in fall risk. This may be due to the decreased kinematic variability as a result of the reduced signal-dependent noise of the smaller muscle forces that are required for slower. These insights may be used in the development of fall prevention programs in order to better identify those at increased risk of falling and to target those factors that influence fall risk most.     

The Mmogo-Method™: Discovering Symbolic Community Interactions

In this article the development and implementation of the Mmogo-Method? is discussed as a culture-sensitive data collection method. The Mmogo-Method? provides opportunities for social researchers to gain a deeper understanding of the cultural symbolism in which social life is embedded and that informs experiences, perceptions and behaviour. In this method, people create their own data by making visual presentations that reflect contextually grounded symbolic meanings. Theoretical underpinnings of social constructionism, symbolic interactionism and community psychology are discussed and applied as the rationale for the development and implementation of the Mmogo-Method?. Examples of research using the Mmogo-Method? are provided to illustrate its value and various different application possibilities. The Mmogo-Method? attempts to produce community-based knowledge that is gathered and disseminated in a coherent way; thereby contributing to the possibility that indigenous knowledge may form part of national and international discussions.     

Disaster recovery experiences of a South African rural farming community

This study explored the bush fire disaster experiences and coping of South African farmers. Participants consisted of seven male farmers (6?=?White Afrikaans-speaking; 1?=?Black Tswana-speaking). Data were collected using semi-structured interviews, nine months after the disaster, and analysed thematically. The findings showed that the farmers’ recovery was characterised by three distinct, transitioning phases. The first period involved resource-maintenance coping and emotion-focused coping. The second time period was characterised by meaning making related strategies. Finally, the third time period was charactirised by anxiety over reoccurrence and resource-maintenance coping. The results also suggest that successful coping is reliant on the individual's ability to adapt coping strategies continually, in a context-appropriate manner.     

Different states in visual working memory: when it guides attention and when it does not

Recent studies have revealed a strong relationship between visual working memory and selective attention, such that attention is biased by what is currently on our mind. However, other data show that not all memorized items influence the deployment of attention, thus calling for a distinction within working memory: whereas active memory items function as an attentional template and directly affect perception, other, accessory items do not. We review recent evidence that items compete for the status of 'attentional template' that contains only one object at a time. Neurophysiological results provide insight into these different memory states by revealing a more intricate organization of working memory than was previously thought.     

The automatic and co-occurring activation of multiple social inferences

People make a variety of automatic inferences when observing others' actions. These include inferences about stable dispositions as well as transitory goal states and social situations. However, models of social inference have rarely considered whether different types of automatic inferences can co-occur. We present three experiments in which participants were incidentally exposed to texts depicting behaviors that afforded inferences about actors' traits and the social situations these actors were experiencing. Results from lexical decision and probe-recognition tasks revealed heightened activation of both trait and situational inferences; furthermore, this co-occurring activation was spontaneous, unconscious, and independent of processing resources or specific impression-formation goals. A fourth experiment extended these findings by showing that when participants were asked to make deliberate attributional judgments of the same set of behaviors, typical goal-directed biases reflecting the selection of either trait or situational interpretations emerged. Implications for social inference processes are discussed.     

Optimal Self‐esteem is Contingent: Intrinsic Versus Extrinsic and Upward Versus Downward Contingencies

We argue that noncontingent, unconditional self‐esteem is not optimal but defensive. We introduce the concept of intrinsic contingency, where self‐esteem is affected by whether one's actions are self‐congruent and conducive to personal growth. Whereas external contingencies, especially social and appearance, were negatively correlated with authenticity, self‐compassion, and personal well‐being, intrinsic contingencies were positively correlated with these measures, and uncorrelated with aggression and self‐esteem instability. Participants with high intrinsic contingency rated higher on measures of psychological adaptiveness than noncontingent participants. In addition, we distinguish upward from downward contingencies, the latter being more harmful in case of external contingencies but not for intrinsic contingencies. We conclude that intrinsic contingency, rather than noncontingency, may reflect true self‐esteem as implied in self‐determination theory. Copyright © 2011 John Wiley & Sons, Ltd.     

Search reaction time for single targets in multiletter stimuli with brief visual displays

The same set of Ss was run In an LT (single late target letter followed an earher multiletter display) and an ET (single early target preceded a later multiletter display) condition. On one-half the trials, the multiletter set included the target. and on the other half, the target was absent. The task of S was to push the “yes” (“no”) button if the target was present (absent), and reaction times were recorded. The most plausible processing model assumed that LT comparisons took place in a verbal-acoustic store and that ET comparisons took place in a visual store. It further assumed that processing within these stores was self-terminating, with rates that differed on “same” and “different” comparisons and which changed as the multiletter set increased. Classes of serial and parallel models that are falsified or supported by the present and similar data are discussed.     

The Process of Growth in Krishna Consciousness and Sacredness in Belgium

The article focuses on the Hare Krishna members in Belgium. The movement owns a temple on the outskirts of a provincial city in the south of the country. Fieldwork was carried out among the ‘temple residents’ (at Radhadesh, the ‘Petite Somme’), those who live in its vicinity, the ‘congregationalists’ in the local centres, and those who are on the way of being initiated. The article focuses on the development members undergo from ‘adepts’ to ‘devotees’, that is from ‘congregationalists’ to becoming full-time ‘temple residents’ in Radhadesh. The question we address concerns the process of members’ growth in Krishna consciousness and sacredness.