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.     

Psychosozialer Versorgungsbedarf bei Arbeitnehmern

Zusammenfassung  Untersuchungen zu Häufigkeit, Verlauf und Ursachen psychischer Erkrankungen bei Arbeitnehmern sind rar. Die Gründe hierfür liegen sowohl auf Seiten der Arbeitsmedizin, die psychosoziale Aspekte wenig berücksichtigt, als auch bei der Psychotherapie, die zu wenig auf die Arbeitssituation eingeht. Die wenigen aussagekräftigen Untersuchungen legen bei Arbeitnehmern eine ähnlich hohe Prävalenz und Behandlungsbedürftigkeit nahe wie in der Allgemeinbevölkerung. Von den Folgen einer störungsinadäquaten Therapie psychischer Erkrankungen sind Arbeitnehmer in besonderem Maße betroffen, da die Erkrankungen nicht nur zu erheblichem persönlichem Leid führen, sondern durch Chronifizierung zu enormen Kosten in der medizinischen Versorgung beitragen. Außerdem sind sie durch krankheitsbedingte Fehlzeiten und (Früh-)Berentungen auch die Ursache weit reichender Produktionsausfälle in der Wirtschaft. Obwohl eine Reihe von Maßnahmen der betrieblichen Gesundheitsförderung zur Besserung der psychischen Befindlichkeit von Arbeitnehmern verfügbar sind, werden sie gegenwärtig noch zu selten eingesetzt und noch weniger evaluiert.

Valence of distractor words increases the effects of irrelevant speech on serial recall

Participants memorized target words in silence or while ignoring neutral or valent (positive or negative) distractor words that could be either possessor-relevant or other-relevant. Distractor words impaired recall performance, but valent distractor words caused more disruption than neutral distractors, and negative distractors caused more disruption than positive distractors. The results are problematic for explanations of the irrelevant speech effect within working memory models that do not specify an explicit role of attention in the maintenance of information for immediate serial recall.     

On doing two things at once: Temporal constraints on actions in language comprehension

In two experiments, we investigated how text comprehension is influenced by the interaction between the properties of actions and the temporal relations specified by adverbs. Participants read short narratives describing a protagonist who performed two actions that involved similar sensorimotor systems (e.g., chopping wood and painting a fence) or different ones (e.g., whistling a melody and painting a fence). The actions were described as simultaneous or successive by means of the temporal adverbs while and after, respectively. Comprehension, both in Spanish and in English, was markedly impaired (longer reading times and lower subjective coherence) for sentences including the adverb while and actions involving the same sensorimotor system. However, when one of the same sensorimotor system actions was described as a mental plan (e.g., chopping wood and thinking of painting a fence), comprehension was equally easy with the adverbs while and after. These results are compatible with a revised version of the indexical hypothesis that specifies how comprehension is guided by syntax and embodied constraints within multiple noninteracting mental spaces.     

Visual kin recognition and family resemblance in chimpanzees (Pan troglodytes)

The male-offspring biased visual kin recognition in chimpanzees (Pan troglodytes) reported by L. A. Parr and F. B. M. de Waal (1999) was replicated with human (Homo sapiens) participants and a principal components analysis (PCA) of pixel maps of the chimpanzee face photos. With the same original materials and methods, both humans and the PCA produced the same asymmetry in kin recognition as found with the chimpanzees. The PCA suggested that the asymmetry was a function of differences in the distribution of global characteristics associated with the framing of the faces in the son and daughter test sets. Eliminating potential framing biases, either by cropping the photos tightly to the faces or by rebalancing the recognition foils, eliminated the asymmetry but not human participants' ability to recognize chimpanzee kin.     

The use of experimenter-given cues by South African fur seals (<Emphasis Type="Italic">Arctocephalus pusillus</Emphasis>)

Dogs can use a variety of experimenter-given cues such as pointing, head direction, and eye direction to locate food hidden under one of several containers. Some authors have proposed that this is a result of the domestication process. In this study we tested four captive fur seals in a two alternative object choice task in which subjects had to use one of the following experimenter-given cues to locate the food: (1) the experimenter pointed and gazed at one of the objects, (2) the experimenter pointed at only one of the objects, (3) the experimenter gazed at only one of the objects, (4) the experimenter glanced at only one of the objects, (5) the experimenter pointed and gazed at one of the objects but was sitting closer to one object than to the other, (6) the experimenter pointed only with the index finger at one of the objects, (7) the experimenter presented a replica of one of the objects. The fur seals were able to use cues which involved a fully exposed arm or a head direction, but failed to use glance only, the index finger pointing and the object replica cues. The results showed that a domestication process was not necessary to develop receptive skills to cues given by an experimenter. Instead, we hypothesize that close interactions with humans prior to testing enabled fur seals to use some gestural cues without formal training. We also analyzed the behavior of the seals depending on the level of difficulty of the task. Behavioral signs of hesitation increased with task difficulty. This suggests that the fur seals were sensitive to task difficulty.     

Coping assessment in adolescents

The aim of this work was to obtain an abridged form of the Adolescent Coping Scale (Spanish version) that included items representative of the various factorial dimensions identified as stable. The scale (80 items) was administered to 800 Argentine adolescents. Factor analyses, principal axes and oblimin solution, were performed. An abridged scale was obtained, consisting of 46 items that were grouped into 11 dimensions: Cognitive Redefinition, Self-Blame, Fatalism, Evasion Through Amusement, Problem-Focused Coping (which includes requests for information and action), Evasion Through Physical Activity, Emotional Support, Emotional Discharge and Somatization, Anxiety, Isolation, and No Action. The reliability coefficients were found to be satisfactory.     

Processing of temporal information: Evidence from eye movements

In two experiments, we recorded eye movements to study how readers monitor temporal order information contained in narrative texts. Participants read short texts containing critical temporal information in the sixth sentence, which could be either consistent or inconsistent with temporal order information given in the second sentence. In Experiment 1, inconsistent sentences yielded more regressions to the second sentence and longer refixations of it. In Experiment 2, this pattern of eye movements was shown only by readers who noticed the inconsistency and were able to report it. Theoretical and methodological implications of the results for research on text comprehension are discussed.