Responses of wild skuas (Catharacta antarctica ssp. lonnbergi) to human cues in cooperative and competitive social contexts.

Many animals respond to and use social cues emitted by other species (e.g., head direction). In the context of human-animal communication, these capacities have been attributed to regular and longstanding exposure to humans. We presented wild brown skuas (Catharacta antarctica ssp. lonnbergi) with two versions of an object-choice paradigm. In the cooperative version (Experiment 1), one human experimenter provided a simple and salient cue indicating which of two containers covered a food reward. The cues administered consisted of touching, looking at, pointing at, or pointing and looking at the container hiding food. In Experiment 1, skuas could thus cooperate with an experimenter by using the cues provided to locate the rewarded container. In the competitive version (Experiment 2), two human experimenters presented a platform with a visible food reward. In six experimental conditions, we varied experimenters' body orientation, head orientation, eye-gaze direction, face occlusion, and mouth occlusion, as well as the platform's location, ensuring that in each case only one experimenter had visual access to the rewarded platform. Here, birds could compete with the experimenters by robbing the human who does not see the food. Skuas failed to use human-given cues spontaneously in Experiment 1, and took the reward regardless of whether the experimenters could see in Experiment 2. Our results contrast with those obtained on other wild birds with pre-experience with humans. Hopefully, our findings will stimulate further research in order to illuminate the potential role of such experience in the capacity to respond to and use human-given cues. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reliability and concurrent validity of the Acti'MET calculator: A new tool to assess physical activity in cardiac rehabilitation.

OBJECTIVE: We created a tool for assessing physical activity (PA), the Acti'MET calculator, to quickly estimate weekly energy expenditure. This study aimed to assess the metrological properties of the tool in cardiac rehabilitation (CR). METHODS: Two examiners evaluated the reliability and concurrent validity of the tool with cardiac patients. The validity of the tool was assessed by comparison with other classical methods for measurement of PA such as the Dijon Physical Activity Score (PAS) and the International Physical Activity Questionnaire (IPAQ) score, the 6-min walk test (6MWT) and the cardiopulmonary maximal exercise test. Correlation was assessed by Pearson or Spearman correlation analysis. RESULTS: For the 36 cardiac patients (mean age 55±11 years, 24 men), inter-rater and intra-rater reliabilities were strong: r=0.87 and r=0.98, respectively, both P<0.0001. We found a strong correlation of the Acti'MET score with the IPAQ score (r=0.88, P<0.0001), moderate correlation with the PAS (r=0.39, P<0.05) and 6MWT (r=0.54, P<0.01), and no correlation with peak power output. CONCLUSION: The Acti'MET calculator is reliable, valid and easy to use for assessing PA in CR. This tool seems to well reflect the weekly PA, unlike the PAS, which evaluates PA on a yearly basis.

Dry-land strength training vs. electrical stimulation in sprint swimming performance.

This study was undertaken to compare the effects of dry-land strength training vs. an electrical stimulation program on swimmers. Twenty-four national-level swimmers were randomly assigned to 3 groups: the dry-land strength training program (S), the electrical stimulation training program (ES), and the control (C) group. The training program lasted 4 weeks. The subjects were evaluated before the training, at the end of the training program, and 4 weeks later. The outcome values ascertained were peak torque during arm extension at different velocities (from -60 to 180°·s(-1)) using an isokinetic dynamometer and performance, stroke rate, and stroke length during a 50-m front crawl. A significant increase in swimming velocity and peak torque was observed for both S and ES at the end of the training and 4 weeks later. Stroke length increased in the S group but not in the ES group. However, no significant differences in swimming velocity between S and ES groups were observed. No significant changes occurred in the C group. Programs combining swimming training with dry-land strength or electrical stimulation programs led to a similar gain in sprint performance and were more efficient than swimming alone.

Effects of a physical training programme on cognitive function and walking efficiency in elderly persons with dementia.

OBJECTIVES: To study the effects of physical stimulation based on walking exercises, equilibrium and endurance on cognitive function and walking efficiency in patients with dementia. METHODS: Randomized controlled trial including 31 subjects suffering from dementia (age: 81.8 +/- 5.3 years). The intervention group (n = 16) benefited from a 15-week physical activity programme involving three 1-hour sessions per week. The control group (n = 15) did not practice any physical activities. Before and after rehabilitation, all subjects were evaluated with the Rapid Evaluation of Cognitive Functions test (ERFC French version) and walking analysis. RESULTS: After the 15 weeks of rehabilitation, the subjects from the intervention group improved their overall ERFC score (p < 0.01), while those in the control group decreased their overall ERFC score. Interactions were also observed between walking parameters and groups (p < 0.01); the intervention group improved walking capacities through heightened walking speed, stride length and a reduction in double limb support time. Lastly, the subjects from the control group presented a reduction in both walking speed and stride length. CONCLUSION: This study shows that a physical activity programme can slow cognitive decline and improve quality of walking in elderly persons suffering from dementia.

Performances of a polymer-cholesteric-liquidcrystal output-coupler in Nd-doped fiber lasers.

The performances and characteristics of a polymer-cholestericliquid-crystal reflector, used as an output coupler in a Nd-doped fiber laser, are presented. We show that a judicious combination of a linear polarizer and a quarter wave plate with the cholesteric coupler allows for a continuous scanning of the output-intensity from zero to a maximum value following the well-known Malus law. The results are shown to be contained in a simple Jones Matrix formalism. The LP-QW-PCLC combination is characterized by a reflection coefficient that can be freely adjusted from 0 to 1 by a simple rotation of the quarter-wave plate.