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Abstract When terrestrial organisms locomote in natural settings, they must navigate complex surfaces that vary in incline angles and substrate roughness. Variable surface structures are common in arboreal environments and can be challenging to traverse. This study examines the walking gait of katydids (Tettigoniidae) as they traverse a custom-built platform with varying incline angles (30○, 45○, 60○, 75○, 90○) and substrate roughness (40, 120, and 320 grit sandpaper). Our results show that katydids walk more slowly as the incline angle increases and as katydid mass increases, with a decrease of around 0.3 body lengths per second for every 1○ increase in incline. At steeper inclines and larger sizes, katydids are also less likely to use an alternating tripod gait, opting instead to maintain more limbs in contact with the substrate during walking. Katydids also increased average duty factor when climbing steeper inclines and with increasing body mass. However, substrate roughness did not affect walking speed or gait preference in our trials. These findings provide insights into how environmental factors influence locomotor strategies in katydids and enhance our understanding of effective locomotor strategies in hexapods. 

Over the past two decades of research, increased media consumption in the context of collective traumas has been cross-sectionally and longitudinally linked to negative psychological outcomes. However, little is known about the specific information channels that may drive these patterns of response. The current longitudinal investigation uses a probability-based sample of 5,661 Americans measured at the onset of the COVID-19 pandemic to identify a) distinct patterns of information-channel use (i.e., dimensions) for COVID-related information, b) demographic correlates of these patterns, and c) prospective associations of these information channel dimensions with distress (i.e., worry, global distress, and emotional exhaustion), cognition (e.g., beliefs about the seriousness of COVID-19, response efficacy, and dismissive attitudes), and behavior (e.g., engaging in health-protective behaviors and risk-taking behaviors) 6 mo later. Four distinct information-channel dimensions emerged: journalistic complexity; ideologically focused news; domestically focused news; and nonnews. Results indicate that journalistic complexity was prospectively associated with more emotional exhaustion, belief in the seriousness of the coronavirus, response efficacy, engaging in health-protective behaviors, and less dismissiveness of the pandemic. A reliance on conservative-leaning media was prospectively associated with less psychological distress, taking the pandemic less seriously, and engaging in more risk-taking behaviors. We discuss the implications of this work for the public, policy makers, and future research. 

The COVID-19 (coronavirus disease 2019) pandemic is a collective stressor unfolding over time; yet, rigorous empirical studies addressing its mental health consequences among large probability-based national samples are rare. Between 18 March and 18 April 2020, as illness and death escalated in the United States, we assessed acute stress, depressive symptoms, and direct, community, and media-based exposures to COVID-19 in three consecutive representative samples from the U.S. probability-based nationally representative NORC AmeriSpeak panel across three 10-day periods (total N = 6514). Acute stress and depressive symptoms increased significantly over time as COVID-19 deaths increased across the United States. Preexisting mental and physical health diagnoses, daily COVID-19–related media exposure, conflicting COVID-19 information in media, and secondary stressors were all associated with acute stress and depressive symptoms. Results have implications for targeting public health interventions and risk communication efforts to promote community resilience as the pandemic waxes and wanes over time. 

Abstract DNA nanotechnology allows for the design of programmable DNA-built nanodevices which controllably interact with biological membranes and even mimic the function of natural membrane proteins. Hydrophobic modifications, covalently linked to the DNA, are essential for targeted interfacing of DNA nanostructures with lipid membranes. However, these hydrophobic tags typically induce undesired aggregation eliminating structural control, the primary advantage of DNA nanotechnology. Here, we study the aggregation of cholesterol-modified DNA nanostructures using a combined approach of non-denaturing polyacrylamide gel electrophoresis, dynamic light scattering, confocal microscopy and atomistic molecular dynamics simulations. We show that the aggregation of cholesterol-tagged ssDNA is sequence-dependent, while for assembled DNA constructs, the number and position of the cholesterol tags are the dominating factors. Molecular dynamics simulations of cholesterol-modified ssDNA reveal that the nucleotides wrap around the hydrophobic moiety, shielding it from the environment. Utilizing this behavior, we demonstrate experimentally that the aggregation of cholesterol-modified DNA nanostructures can be controlled by the length of ssDNA overhangs positioned adjacent to the cholesterol. Our easy-to-implement method for tuning cholesterol-mediated aggregation allows for increased control and a closer structure–function relationship of membrane-interfacing DNA constructs — a fundamental prerequisite for employing DNA nanodevices in research and biomedicine.