Does Individual Performance Influence Antipredator Behavioral Strategy Choice in Chameleons?

Animals are under a constant selective pressure to avoid predation. They are often equipped with several anti-predatory behavior strategies based on their morphology, physiology and behavior. Maintaining a suite of behaviors allows animals to choose strategies that may be better equipped for particular environments and types of predators. Chameleons are a particularly interesting model to study the relationship between these adaptations because of how they have specialized to their environment. These animals have adapted traits that are well-suited for a largely arboreal lifestyle, but as a consequence, produce relatively slow locomotion. As a result, they may need to rely on alternative strategies that do not hinge on speed. Chameleons may still choose to flee to avoid predation, but they may also undergo cryptic color changes or behave aggressively. Previous work also suggests that their antipredator strategies vary significantly with body size and habitat type. We examined the functional basis for variation in antipredator behavioral decisions in veiled chameleons (Chamaeleo calyptratus) of small, medium, and large size classes. Individuals underwent a series of mock predation trials and their behaviors were classified into fleeing, crypsis , aggression , or other. We then quantified the performance capacities underlying each strategy by measuring sprint speed and acceleration for fleeing, degree of color change for crypsis, and bite force for aggression. Our results indicate that certain performance capacities across size classes influence which strategy is chosen during mock predation trials. The importance of the functional capacity to perform each behavior in antipredator behavior decision making provides considerable insight into the relationship between behavior, environment, and physiology

Validation of two measures for assessing English vocabulary knowledge on web-based testing platforms: Long-form assessments

The goal of the current work was to develop and validate web-based measures for assessing English vocabulary knowledge. Two existing paper-and-pencil assessments, the Vocabulary Size Test (VST) and the Word Familiarity Test (WordFAM), were modified for web-based administration. In Experiment 1, participants (n = 100) completed the web-based VST. In Experiment 2, participants (n = 100) completed the web-based WordFAM. Results from these experiments confirmed that both tasks (1) could be completed online, (2) showed expected sensitivity to English frequency patterns, and (3) revealed high split-half reliability, suggesting that stable vocabulary assessment could be achieved with fewer test items. Based on the results of Experiments 1 and 2, two “brief” versions of the VST and WordFAM were developed. Each version consisted of approximately half of the items from the full assessment, with novel items presented across the two brief versions of each assessment. In Experiment 3, participants (n = 85) completed one brief version of both the VST and WordFAM at session one, followed by the other brief version of each task at session two. The results showed high test-retest reliability for both the VST (r = 0.68) and WordFAM (r = 0.82). The two brief assessments also showed moderate convergent validity (ranging from r = 0.38 to r = 0.59) indicative of construct validity for each assessment. This work provides open-source vocabulary knowledge assessments with normative data that researchers and clinicians can use to foster high quality data collection in web-based environments

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes