23 Works

Autonomous Vehicles and the Ethical Tension Between Occupant and Non-Occupant Safety

Jason Borenstein, Joseph Herkert & Keith Miller
Given that the creation and deployment of autonomous vehicles is likely to continue, it is important to explore the ethical responsibilities of designers, manufacturers, operators, and regulators of the technology. We specifically focus on the ethical responsibilities surrounding autonomous vehicles that these stakeholders have to protect the safety of non-occupants, meaning individuals who are around the vehicles while they are operating. The term “non-occupants” includes, but is not limited to, pedestrians and cyclists. We are...

Dimensional analysis of spring-wing systems reveals performance metrics for resonant flapping-wing flight

Nicholas Gravish, James Lynch, Jeff Gau & Simon Sponberg
Flapping-wing insects, birds, and robots are thought to offset the high power cost of oscillatory wing motion by using elastic elements for energy storage and return. Insects possess highly resilient elastic regions in their flight anatomy that may enable high dynamic efficiency. However, recent experiments highlight losses due to damping in the insect thorax that could reduce the benefit of those elastic elements. We performed experiments on, and simulations of a dynamically-scaled robophysical flapping model...

Microtus californicus toothrow and molar .tps files

Jenny McGuire & Daniel Lauer
Aim. This study examines how climate shaped Microtus californicus (Rodentia: Arvicolinae) ecomorphology throughout the Quaternary. It tests three hypotheses: (1) climate corresponds with consistent shape variation in M. californicus dentition; (2) Quaternary warming and drying trends caused M. californicus morphotypes to predictably shift in range through time; (3) Quaternary warming and drying led to predictable changes in tooth morphological variation. Finally, we discuss how shifts in climate-linked morphological variation may affect the potential of M....

Effects of future climate on coral-coral competition

Nicole Johnston, Mark Hay, Valerie Paul & Justin Campbell
As carbon dioxide (CO 2 ) levels increase, coral reefs and other marine systems will be affected by the joint stressors of ocean acidification (OA) and warming. The effects of these two stressors on coral physiology are relatively well studied, but their impact on biotic interactions between corals are poorly understood. While coral-coral interactions are less common on modern reefs, it is important to document the nature of these interactions to better inform restoration strategies...

Environmental stress gradients regulate the relative importance of predator density- and trait-mediated indirect effects in oyster reef communities

Jessica Pruett & Marc Weissburg
Predators affect community structure by influencing prey density and traits, but the importance of these effects often is difficult to predict. We measured the strength of blue crab predator effects on mud crab prey consumption of juvenile oysters across a flow gradient that inflicts both physical and sensory stress to determine how the relative importance of top predator density-mediated indirect effects (DMIEs) and trait-mediated indirect effects (TMIEs) change within systems. Overall, TMIEs dominated in relatively...

The visual arrays task: Visual storage capacity or attention control?

Jessie Martin, Jason Tsukahara, Cody Mashburn, Christopher Draheim, Zach Shipstead, Edward Vogel & Randall Engle
Extant literature suggests that performance on visual arrays tasks reflects limited-capacity storage of visual information. However, there is evidence to suggest that visual arrays task performance also reflects individual differences in controlled processing. The purpose of this paper is to empirically evaluate the degree to which visual arrays tasks are more closely related to memory storage capacity or measures of attention control. To this end, we conducted new analyses on a series of large data...

Data from: Warming alters plant phylogenetic and functional community structure

Juntao Zhu, Yangjian Zhang, Xian Yang, Ning Chen, Shaopeng Li, Pandeng Wang & Lin Jiang
Climate change is known to affect many facets of the Earth’s ecosystems. However, little is known about its impacts on phylogenetic and functional properties of ecological communities. Here we studied the responses of plant communities in an alpine grassland on the Tibetan Plateau to environmental warming across taxonomic, phylogenetic, and functional levels in a six-year multiple-level warming experiment. While low-level warming did not alter either plant species richness or phylogenetic/functional community structure, high-level warming significantly...

Mechanics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

Richard Nuckols, Kota Takahashi, Dominic Farris, Sarai Mizrachi, Raziel Riemer & Gregory Sawicki
Lower-limb wearable robotic devices can improve clinical gait and reduce energetic demand in healthy populations. To help enable real-world use, we sought to examine how assistance should be applied in variable gait conditions and suggest an approach derived from knowledge of human locomotion mechanics to establish a ‘roadmap’ for wearable robot design. We characterized the changes in joint mechanics during walking and running across a range of incline/decline grades and then provide an analysis that...

Backing up into advocacy: The case of smartphone driver distraction

Robert Rosenberger
For the last decade, I’ve been studying the topic of the driving impairment of smartphones. While this began as an exclusively academic project, it has increasingly compelled public engagement. One example of this came in an opinion piece I wrote in 2018 in response to a new traffic law. I take the opportunity here to fill out the academic backstory of this particular op-ed, reflect on how this larger project has evolved to include an...

Data from: Quorum-sensing signaling by chironomid egg masses’ microbiota affects haemagglutinin/protease (HAP) production by Vibrio cholerae

Rotem Sela, Brian Hammer & Malka Halpern
Vibrio cholerae, the causative agent of cholera, is commonly isolated, along with other bacterial species, from chironomid insects (Diptera: Chironomide). Nevertheless, its prevalence in the chironomid egg masses’ microbiota is less than 0.5%. V. cholerae secretes haemagglutinin/protease (HAP) that degrades the gelatinous matrix of chironomid egg masses and prevents hatching. Quorum sensing (QS) activates HAP production in response to accumulation of bacterial autoinducers (AIs). Our aim was to define the impact of chironomid microbiota on...

Data from: Synergistic effects of nitrogen and CO2 enrichment on alpine grassland biomass and community structure

Juntao Zhu, Yangjian Zhang, Xian Yang, Ning Chen & Lin Jiang
Global environmental change is altering Earth’s ecosystems. However, much research has focused on ecosystem-level responses, and we know substantially less about community-level responses to global change stressors. Here we conducted a 6-year field experiment in a high-altitude (4600 m above sea level) alpine grassland on the Tibetan Plateau to explore the effects of nitrogen (N) addition and rising atmospheric CO2 concentration on plant communities. Our results showed that N and CO2 enrichment had synergistic effects...

Species responses to changing precipitation depends on trait plasticity rather than trait means and intraspecific variation

Bingwei Zhang, Yann Hautier, Xingru Tan, Cuihai You, Marc Cadotte, Chengjin Chu, Lin Jiang, Xinghua Sui, Tingting Ren, Xingguo Han & Shiping Chen
1. Trait-based approaches are key to develop mechanistic understanding of differences in plant species performance under environmental change. While mean trait values have been widely used to link functional traits to species performance, the contribution of intraspecific trait variation and trait plasticity remains unclear. Moreover, environmentally induced changes in species biomass is caused by changes in the number of individuals and individual growth rate, both of which should be influenced by trait differences and plasticity....

Breaking a species barrier by enabling hybrid recombination

G. Ozan Bozdag, Jasmine Ono, Jai A. Denton, Emre Karakoc, Neil Hunter, Jun-Yi Leu & Duncan Greig
Hybrid sterility maintains reproductive isolation between species by preventing them from exchanging genetic material. Anti-recombination can contribute to hybrid sterility when different species’ chromosome sequences are too diverged to cross-over efficiently during hybrid meiosis, resulting in chromosome mis-segregation and aneuploidy. The genome sequences of the yeasts Saccharomyces cerevisiae and Saccharomyces paradoxus have diverged by about 12% and their hybrids are sexually sterile: nearly all of their gametes are aneuploid and inviable. Previous methods to increase...

Data from: Diverse and complex muscle spindle afferent firing properties emerge from multiscale muscle mechanics

Kyle Blum, Brian Horslen, Kenneth Campbell, Brian Horslen, Paul Nardelli, Stephen Housley, Timothy Cope & Lena Ting
Despite decades of research, we lack a mechanistic framework capable of predicting how movement-related signals are transformed into the diversity of muscle spindle afferent firing patterns observed experimentally, particularly in naturalistic behaviors. Here, a biophysical model demonstrates that well-known firing characteristics of mammalian muscle spindle Ia afferents – including movement history dependence, and nonlinear scaling with muscle stretch velocity – emerge from first principles of muscle contractile mechanics. Further, mechanical interactions of the muscle spindle...

Category norms with a cross-sectional sample of adults in the United States: Consideration of cohort, age, and historical effects on semantic categories

Nichol Castro, Taylor Curley & Christopher Hertzog
This paper describes normative data for newly collected exemplar responses to 70 semantic categories described in previous norming studies (Battig & Montague, 1969; Van Overschelde, Rawson, & Dunlosky, 2004; Yoon et al., 2004). These categories were presented to 246 Young (18 – 39 years), Middle (40 – 59 years), and Older (60 years and older) English-speaking adults living in the United States who were asked to generate as many category exemplars as possible for each...

Island biogeography of soil bacteria and fungi: similar patterns, but different mechanisms

Shaopeng Li, Pandeng Wang, Yongjian Chen, Maxwell Wilson, Xian Yang, Chao Ma, Jianbo Lu, Xiao-Yong Chen, Jianguo Wu, Wen-Sheng Shu & Lin Jiang
Microbes, similar to plants and animals, exhibit biogeographic patterns. However, in contrast with the considerable knowledge on the island biogeography of higher organisms, we know little about the distribution of microorganisms within and among islands. Here, we explored insular soil bacterial and fungal biogeography and underlying mechanisms, using soil microbiota from a group of land-bridge islands as a model system. Similar to island species-area relationships observed for many macroorganisms, both island-scale bacterial and fungal diversity...

Data from: Experimental demonstration of the importance of keystone communities for maintaining metacommunity biodiversity and ecosystem functioning

Xian Yang, Jiaqi Tan, Kevin Harry Sun & Lin Jiang
As local communities within a metacommunity may differ considerably in their contributions to biodiversity and ecosystem functioning, it has been suggested that conservation priority should be given to disproportionately important local communities (i.e., keystone communities). However, we know little about what characterizes a keystone community. Using laboratory protist microcosms as the model system, we examined how the environmental uniqueness and location of a local community affect its contributions to the metacommunities. We found that the...

Warming effect on ecosystem stability

Quan Quan, Fangyue Zhang, Lin Jiang, Han Y. H. Chen, Jinsong Wang, Fangfang Ma, Bing Song & Shuli Niu
1. Ecosystem stability is essential to its sustainable functions and services to humanity. Although climate warming is projected to vary from 1-5ºC by the end of 21st century, how the temporal stability of plant community biomass production responds to different warming scenarios remains unclear. 2. To fill this knowledge gap, we conducted a 6-year field experiment with three levels of warming treatments (control, + 1.5oC, + 5oC) by using infrared radiators, in an alpine meadow...

Minnesota peat viromes reveal terrestrial and aquatic niche partitioning for local and global viral populations

Anneliek Ter Horst, Christian Santos-Medellín, Jackson Sorensen, Laura Zinke, Rachel Wilson, Eric Johnston, Gareth Trubl, Jennifer Pett-Ridge, Steven Blazewicz, Paul Hanson, Jeffrey Chanton, Christopher Schadt, Joel Kostka & Joanne Emerson
Background: Peatlands are expected to experience sustained yet fluctuating higher temperatures due to climate change, leading to increased microbial activity and greenhouse gas emissions. Despite mounting evidence for viral contributions to these processes in thawing permafrost, little is known about viruses in other peatlands. More generally, soil viral biogeography and its potential drivers are poorly understood at both local and global scales. Here, 87 metagenomes and five viral size-fraction metagenomes (viromes) from a boreal peatland...

Data from: Nanometer-scale structure differences in the myofilament lattice spacing of two cockroach leg muscles correspond to their different functions

Travis Carver Tune, Weikang Ma, Thomas Irving & Simon Sponberg
Muscle is highly organized across multiple length scales. Consequently, small changes in the arrangement of myofilaments can influence macroscopic mechanical function. Two leg muscles of a cockroach, have identical innervation, mass, twitch responses, length-tension curves, and force-velocity relationships. However, during running, one muscle is dissipative (a "brake"), while the other dissipates and produces significant positive mechanical work (bifunctional). Using time resolved x-ray diffraction in intact, contracting muscle, we simultaneously measured the myofilament lattice spacing, packing...

The evolution of virulence in Pseudomonas aeruginosa during chronic wound infection

Jelly Vanderwoude, Derek Fleming, Sheyda Azimi, Urvish Trivedi, Kendra Rumbaugh & Stephen Diggle
Opportunistic pathogens are associated with a number of chronic human infections, yet the evolution of virulence in these organisms during chronic infection remains poorly understood. Here, we tested the evolution of virulence in the human opportunistic pathogen Pseudomonas aeruginosa in a murine chronic wound model using a two-part serial passage and sepsis experiment, and found that virulence evolved in different directions in each line of evolution. We also assessed P. aeruginosa adaptation to a chronic...

Caught in a bottleneck: Habitat loss for woolly mammoths in central North America and the ice-free corridor during the last deglaciation

Yue Wang, Chris Widga, Russell Graham, Jenny McGuire, Warren Porter, David Wårlind & John Williams
The dataset is to describe the habitat structure and bioenergetic characteristics of woolly mammoths (Mammuthus primigenius) in North America during the last deglaciation between 15 and 10 ka. The habitat structure includes fractional woody cover (FWC) and net primary productivity (NPP) for 20 plant functional types (PFTs). NPP is based on the dynamic vegetation model LPJ-GUESS (LPJG). FWC is based on LPJ-GUESS and fossil pollen records in the Neotoma Paleoecology Database. The bioenergetic characteristics of...

Registration Year

  • 2020

Resource Types

  • Dataset
  • Text


  • Georgia Institute of Technology
  • Sun Yat-sen University
  • Institute of Geographic Sciences and Natural Resources Research
  • East China Normal University
  • University of California, Davis
  • Northwestern University
  • National Oceanography Centre
  • Smithsonian Marine Station
  • Lund University
  • Hangzhou Normal University